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PLANTS, SEEDS, AND CURRENTS IN
THE WEST INDIES AND AZORES

PLANTS, SEEDS, AND
CURRENTS IN THE
WEST INDIES AND
AZORES

THE RESULTS OF INVESTIGATIONS CARRIED
OUT IN THOSE REGIONS BETWEEN 1906
AND 1914

BY

H. B. GUPPY, M.B., F.R.S.E.

WITH THREE MAPS AND A FRONTISPIECE

LONDON
WILLIAMS AND NORGATE

14 HENRIETTA STREET, COVENT GARDEN, W.C.

1917

Printed in Great Britain by
Richard Clay & Sons, Limited,
brunswick st., stamford st., s.e.,
and bungay, suffolk.

science;

QK

101

PREFACE

With the exception of the section on the Azores, this work
was practically completed before the war began; and it is now
presented very much as it was written in the pre-war period. Un-
fortunately I greatly under-rated the task involved in the pro-
duction of the fair copy; and for this reason, as well as through
sickness and other causes, there has been considerable delay in its
preparation for the press.

Associated with my observations on seeds and fruits, the results
of which were published in 1912 under the title of Studies in Seeds
and Fruits^ the work embodied in these pages represents about
ten years of my life. The two winters of 1906-8 were spent in
Jamaica, that of 1908-9 mainly in Grenada but also in Tobago
and Trinidad, and that of 1910-11 in the Turks Islands. Subse-
quently two sojourns were made in the Azores, the first from the
middle of February to the end of April 1913, and the second from
the middle of June to the middle of August 1914.

The great lesson that I have learned from the numerous difficult
distribution-problems presented in the West Indian region, is that
one can no longer fight shy of accepting in principle the conclusions
relating to past changes in the arrangement of land and water in
the Caribbean area, which have long been formulated by English
and American geologists and zoologists. The witness of the living
plant is often quite as insistent as the testimony of the rocks. Yet,
although the original holders of such views stood more or less alone
in their advocacy of them forty or fifty years ago, some of them,
like Mr. Lechmere Guppy, who died recently at Port-of-Spain,
lived to see their final justification.

The inclusion of the Azores within my field of investigation
arose from a desire to come in contact with some of the problems
presented by the floras of the Atlantic Islands. In the previous
decade, 1896-1906, I had been brought face to face with problems
offered by the islands of the Pacific. Polynesia and the history
of its plant-stocking had occupied much of my thoughts during a
long period, and I turned to Macaronesia with the hope that as
typified in the Azores this region might bring me once again under
the spell cast by the problems of oceanic distribution. Yet the
outlook was at first far from encouraging, and it was suggested to
me that it was scarcely worth while to take up the study of islands,
concerning which we had long known all that was worth knowing.
However, a re-perusal of Hooker's famous lecture on insular floras
whetted my curiosity, and I soon found that the Macaronesian

vi

PREFACE

islands were rich in distribution-problems almost as fascinating as
those presented by Hawaii and other Polynesian groups.

Yet but few of these problems were directly indicated in the
catalogues of the floras accessible to me; and I realised here, as I
did in the Pacific, that the work of the systematist in framing a
catalogue of a flora represents the means to an end and not the
end itself. In other words, with a list of a flora in our hands we
stand only at the threshold of the study of distribution. Here
also I realised that there is no region so well known that it would
not greatly benefit by a thorough overhaul of all the data from a
generally accepted standpoint of distribution; and the conviction
forced itself upon me that the student of distribution will find his
task nearest-at-hand, not in the discovery of new facts, but in the
elaboration of old ones, and in the adoption of a uniform method
of treatment. The elimination of the introduced plant should be
the first goal of the student of distribution. Yet it is not possible
for him to procure intelligible results, since he employs one method
for the British Islands, another for the Azores, another for New
Zealand, and a fourth for the Hawaiian Islands. The story of the
weed all over the globe is full of significance, but only for the student
of the early history of man.

H. B. GuppY.

" J?05ano," Salcomhe,
South Devon.

Nov. S3, 1916.

LIST OF SOME BOTANICAL AND OTHER
WORKS QUOTED IN THESE PAGES IN CON-
NECTION WITH DISTRIBUTION IN THE
WEST INDIAN REGION AND ELSEWHERE

(Other lists dealing with special subjects are given at the end
of chaps, ii, iii, xi, xiii, xv, xix.)

Catesby, M., Natural History of Carolina, Florida, and the

Bahamas ; i. 1731 ; ii. 1743.
Ernst, A., The New Flora of the Volcanic Island of Krakatau, trans.

by A. C. Seward, Cambridge, 1908.

Rendle!a^B.}^'°'^^ of Jamaica, vol. iii. 19U.

Grisebach, a. H. R., Flora of the British West Indian Islands,
1864.

GuppY, H. B., Dispersal of Plants as illustrated by the Flora of Keeling
Atoll, Journal of the Victoria Institute, London, 1889.

Plant-Dispersal, 1906 (vol. ii. of Observations of a Naturalist
in the Pacific).

Plant-Distribution from an Old Standpoint, Trans, Vict. Inst.,
London, 1907.

Distribution of Plants and Animals, Petermann's Mitteilungen,
1910, heft 2.

Studies in Seeds and Fruits, 1912.
Harshberger, J. W., Phytogeographic Survey of North America
(Engler and Drude's Die Vegetation der Erde, vol. xiii. Leipzig
and New York, 1911).

The Vegetation of South Florida, Travis. W agner Free Institute
of Science of Philadelphia, 1914.
Hart, J. H., Herbarium list. Botanical Department, Trinidad, 1908.
Hemsley, W. B., Reports on the Scientific Results of the Voyage of
H.M.S. Challenger, Botanj^ vol. i. 1885 (reference to this work
is often abbreviated to Chall. Bot.).
Hooker, W. J., The Niger Flora, 1849, including sections by G.

Bentham, J. D. Hooker, and others.
MiLLSPAUGH, C. F., Plantse Utowanae, 1900 (plants collected in the
Antillean cruise of the yacht Utowana).
Plantse Yucatanse, 1903-4.
Flora of the Sand-keys of Florida, 1907.
Praenuncise Bahamenses, 1906-9.

(All publications of the Field Columbian Museum, Chicago.)

vii

viii LIST OF SOME BOTANICAL AND OTHER WORKS

Safford, W. E., Classification of the genus Annona, Contributions
from the United States National Herbarium, vol. 18; Smith-
sonian Institution, Washington, 1914.

(Numerous botanical papers by this author, which are of
great importance both to the botanist and to the student of the
races of man in the tropics of the New World, have appeared
in the last few years in the Journal of the Washington Academy
of Sciences, 1912-15; in the Volta Review, Washington, 1912;
in the Bulletin of the Torrey Botanical Club, 1912 ; in the Journal
of Heredity, Washington, 1915; and in the Smithsonian series
of publications above named.)

ScHARFF, R. F., Distribution and Origin of Life in America, London,
1911.

ScHiMPER, A. F. W., Die Indo-Malayische Strandflora, Jena, 1891.

Spruce, R., Notes of a Botanist on the Amazon and Andes, 1908
(edited by A. R. Wallace).

Urban, L, Symbolic Antillanse, vol. i. 1898-1900; ii. 1900-1901;
iii. 1901-1903; iv. 1903-1911, Leipzig.

CONTENTS

CHAP. PAGB

I WEST INDIAN BEACH-DRIFT 1

II WEST INDIAN DRIFT ON EUROPEAN SHORES ... 20

III THE CURRENTS OF THE ATLANTIC AND THE TRACKS

OF DRIFTING SEEDS AS ILLUSTRATED BY BOTTLE-
DRIFT 46

IV THE SIMILARITY BETWEEN THE WEST INDIAN AND

WEST AFRICAN LITTORAL FLORAS AS EXPLAINED

BY CURRENTS 83

V RHIZOPHORA MANGLE AND THE PLANTS OF THE GREAT

MORASS OF THE BLACK RIVER DISTRICT IN JAMAICA 96

VI THE LARGER FOREIGN DRIFT OF THE TURKS ISLANDS . Ill

VII THE LARGER FOREIGN DRIFT OF THE TURKS ISLANDS

(continued) 138

VIII MISCELLANEOUS PLANTS 166

IX MISCELLANEOUS PLANTS (continued) .... 197

X MISCELLANEOUS PLANTS (contiuucd) .... 225

XI THE GENERAL CHARACTERS AND GEOLOGICAL STRUC-
TURE OF THE TURKS ISLANDS 254

XII THE FLORA OF THE TURKS ISLANDS .... 277

XIII THE CURRENT-CONNECTIONS IN THE SOUTHERN HEMI-

SPHERE 294

XIV DIFFERENTIATION 313

XV DISTRIBUTION 323

XVI THE INFLUENCE OF THE DIVERGENCE OF THE CON-
TINENTS ON THE DISTRIBUTION OF SPHAGNUM AND

CAREX 332

XVII THE AZORES 359

XVIII THE AZORES (coutinucd) 389

XIX THE AZORES (continued) 417

APPENDIX 441

INDEX 505

ix

MAPS AND ILLUSTRATIONS

WEST INDIAN SEEDS AND FRUITS REPRESENTED IN EUROPEAN

BEACH-DRIFT Froutispiece

THE OCEAN CURRENTS To fuce page 46

THE TURKS ISLANDS „ „ 254

THE ISLAND OF PICO, AZORES „ „ 359

xi

PLANTS, SEEDS, AND CURRENTS IN
THE WEST INDIES AND AZORES

CHAPTER I

WEST INDIAN BEACH-DRIFT

The study of the stranded seed and fruit-drift of the West Indian
region, as in the case of my previous investigations in the Pacific
Islands, offered a means of approaching the great problems of plant
distribution. The inquiry was extended over four winters (1906-
1911), and was principally carried out in Jamaica, the Turks Islands,
Trinidad, Tobago, and Grenada. The last winter was spent in the
Turks Islands with the object of studying the seed-drift most fitted
for the traverse across the North Atlantic in the Gulf Stream, since
in those small islands one is able to discriminate with confidence
between the drift of local origin and that brought from outside
regions by the currents.

Generally speaking, the drift has much the same character over
all this region, except perhaps in Trinidad and the adjacent island
of Tobago, where there is added a quantity of strange seeds and fruits
brought by the Equatorial Current from the Amazon and the Orinoco
and from the estuaries and shores of the Guianas and Brazil. It
is also highly probable, as is shown in the discussion of the bottle-
drift data in a later chapter, that West African seed-drift is trans-
ported by the same current to the West Indies ; but there are obvious
difficulties in the way of recognising it, since most of the littoral
plants that constitute the principal sources of the drift are common
to both sides of the tropical Atlantic.

Its Sources. — The seeds and fruits found in the floating drift of
these seas are derived partly from plants growing on the beaches,
partly from plants of the mangrove swamps, and partly from inland
plants growing on river-banks and on the slopes above. They are
to be found in quantities on the beaches, especially in the vicinity
of estuaries. But the scanty materials stranded on the coasts of
Europe, as described in Chapter II., are but the residue of a vast
amount of vegetable debris brought down by rivers to the coast
and washed off the beaches by the currents. By far the greater
mass of these materials must soon find a resting-place amongst the
deposits at the bottom of the sea in the vicinity of their source.

B

2 PLANTS, SEEDS, AND CURRENTS

The Sifting Process. — This sifting out of the less buoyant
materials is well illustrated when we compare the vegetable drift
thrown up on the small islands of the Turks Group with that deposited
on the beaches of the larger islands in the neighbourhood of estuaries,
as in the case of the Orinoco drift piled up on the south side of Trinidad,
or, to take a less conspicuous example, of the drift stranded on the
south coast of Jamaica in the vicinity of the Black River. These
matters will be mentioned in a later page ; but here it may be said
that the foreign drift, which makes up nearly all of the larger materials
stranded on the Turks Islands, presents us with the seeds and fruits
that are most likely to be carried in the Gulf Stream across the
Atlantic. The beach-drift of this small group displays the West
Indian drift in transit at an early stage of the North Atlantic traverse.

If we desired to know what seeds and fruits of the floating drift
of the West Indian seas we ought to find on the shores of Europe,
we must look for them, not on the beaches of the larger islands where
they would be mixed with and sometimes lost among a mass of
vegetable materials of local origin, but on the coast of some low,
scantily vegetated, outlying islet standing well removed from the main
islands. Such an islet would receive on its beaches a sample of the
drift after it has lost all the less buoyant constituents during a
flotation of some weeks in the open ocean. These are just the oppor-
tunities which are offered in the several small islands and islets of
the Turks Group. Here in sample we see the oceanic drift that is
carried swiftly by the Gulf Stream through the Florida Channel and
then past Cape Hatteras eastward to the shores of Europe.

General Description of Drift. — With this object in view I will
at first generally describe West Indian beach-drift, referring in passing
to some of its special characters in particular localities.

In the West Indies, as elsewhere, the local drift is generally pre-
dominant, that is to say, the drift derived from plants growing in the
vicinity, whether at the border of the beaches, or in the coastal and
estuarfne mangrove swamps, or in the interior along the sides of
rivers. It is from the beaches near a large estuary that we can
form the best idea of the nature of the materials that any particular
region supplies to the currents for oceanic transport. If we confined
our attention entirely to the drift brought down by rivers, or to the
materials supplied by shore vegetation, our conception of its general
composition would be incomplete. It is on a beach near an estuary,
where the seeds and fruits derived from the beach plants are mingled
with those from the mangrove vegetation and from the riverside
plants of the interior, that we can learn our lesson concerning local
drift.

Yet this would take no cognisance of the foreign drift, the materials
brought from a distance, often from a continental coast or from some
island hundreds of miles away. This is liable to be masked by the
local drift on a beach near an estuary. It is best sought for and
most easily recognised on some long stretch of beach far from an
estuary, since it is often not difficult there to differentiate between
it and the drift supplied by the beach vegetation. But here again
obstacles may arise. Some knowledge of the flora must be acquired,

WEST INDIAN BEACH-DRIFT

3

and in a large island like Jamaica this is not a light undertaking.
Even with Grisebach's Flora of the British West Indian Islands at my
disposal, a work that bears especially on Jamaican plants, it was
not possible to say with certainty that three of the most interesting
plants represented in Jamaican beach-drift, Carapa guianensis,
Manicaria saccifera, and Sacoglottis amazonica, though not accredited
to the island, did not still survive in some of its extensive coastal
swamps. It will, however, be subsequently shown that in the light
of more recent investigations the probability of their not existing
there is very great.

These are difficulties likely to crop up in the case of all large
tropical islands. Yet the inerusting cirripedes, Serpulce, and other
organisms will frequently aid us in determining whether any par-
ticular fruit or seed is from beyond the sea. It is only the outlying
sand-key, such as occurs in the Turks Islands, that affords the
opportunity of safely differentiating the foreign drift on a beach.
Here after a few weeks spent in examining the local flora there is
little or no trouble in making the discrimination.

The riverside vegetation above the mangroves, the mangrove
formation of the estuary and of the coast swamp, the plants of the
beach and its border, all contribute to the floating drift of these seas.

River- DRIFT above the Mangroves. — A good deal of the materials
brought down by the river, and I have in this sketch the Black River
of Jamaica chiefly in my mind, consists of aquatic plants, such as
Pontederias and Pistias, and of foliage, portions of tree-branches,
etc., which do not count in distribution, and in the case of the floating
plants are soon destroyed by the salt water or dry up when stranded
on the beaches. These aquatic plants form a special feature of the
floating drift of rivers of tropical America, and I have referred to
them in the instance of the Guayas River in Ecuador in my book on
Plant Dispersal (p. 488). Yet the plants of the riverside and of the
wooded slopes of the river-valley above the mangrove-bordered
estuary add a great variety of fruits and seeds to the drift floating
in the stream, as illustrated in the description of the Black River
given near the close of this chapter.

Many of these floating fruits and seeds have little or no effective
value for distribution except along the same river-system. Thus in
the Black River drift occur in numbers the germinating fruits of
Grias cauliflora, the germinating seeds of Symphonia glohidifera, of
Crinum, and of Crudya spicata ; and one may add the seeds of
Fevillea cordifolia, which even when they escape the fate of germina-
tion in the river-drift are far from suited for dispersal over the sea.
It is of importance to remember that through this tendency to germin-
ate when afloat many of the seeds and fruits of the drift of tropical
rivers are rendered useless for purposes of dispersal even across
narrow tracts of sea.

But amongst the fruits and seeds found afloat in West Indian
river-drift, excluding those supplied by the mangroves and their
associates, many others have no effective value for purposes of dis-
tribution. Although the gourds of Crescentia trees and the fruits
of Acrocomia palms are characteristic of this floating drift, the first

4 PLANTS, SEEDS, AND CURRENTS

named carry seeds that have a fleeting vitahty and the second float
only for a few days. Acrocomia fruits, it is true, are represented in
the drift of the Turks Islands, but merely in the form of the empty
*' stones," which, after being freed by the decay of the outer coverings
of the stranded fruit, acquire buoyancy only through the loss of the
seed. Then again both Andira inermis, a tree of the riverside, and
Mammea americana, a tree of the forested slopes of the river-valley,
add their fruits as a rule to the floating drift ; but it is very doubtful
whether their seeds would be fit for germination when the fruits are
stranded on some distant island.

The fruits and seeds carried down by a West Indian river from
the interior to the sea that would be fitted for crossing unharmed a
broad tract of ocean are comparatively few. Taking all the kinds of
seeds and fruits brought down to the sea by the Black River from its
basin above the mangroves, I don't suppose that twenty per cent,
would be capable of reproducing the plant after a traverse of a
hundred miles of ocean. The seeds which are brought down by a
Jamaican river from the interior to the coast in a sound condition
and capable of sustaining without injury the effects of prolonged
flotation in the sea, would include such leguminous seeds as those of
Entada scandens, Mucuna urens, and Dioclea reflexa, all of which
figure in the West Indian drift stranded in a sound condition on the
shores of Europe. Then there would be the " stones " of Spondias
lutea and the long pods of Cassia grandis, which, after they have been
transported by the rivers to the sea, would still be able to carry some
of their seeds unharmed far across the ocean.

Drift supplied by the Mangrove Formation. — We come now
to the vegetation of the mangrove formation as a source of the floating
drift of West Indian seas. We have to distinguish here between
the true mangroves and their associates. Together they form colonies
everywhere, whether on the surface of some newly raised islet or
key, or on the coast, or in the estuaries of the larger islands. Rhizo-
phora mangle, Laguncularia racemosa, and Avicennia nitida are the
mangrove trees proper; and one of their most prominent character-
istics is their viviparous habit, which, however, is less pronounced with
Laguncularia than with the others. The occasional associates of
the mangroves in the larger islands are Anona palustris and Carapa
guianensis. In Trinidad we find also Manicaria saccifera and Saco-
glottis amazonica together with a species of Bactris, a palm that grows
in similar situations. The Manicaria and Sacoglottis trees are con-
spicuous constituents of the estuarine floras of the great rivers of
Venezuela, the Guianas, and Brazil. Though they only just enter
the West Indian region, their fruits are distributed by the currents
far and wide over the Caribbean Sea.

All the above-named trees of the mangrove swamps contribute
to the floating drift of these seas, the true mangroves being repre-
sented in the case of Rhizophora by long seedlings, in the case of
Avicennia by the germinating fruits and seedlings, and in that of
Laguncularia by the fruits, which are often in the germinating con-
dition. Uninjured by flotation in sea-water these seedlings and
germinating fruits are cast ashore, and very soon establish themselves.

WEST INDIAN BEACH-DRIFT

5

On the other hand, with the associates of the mangroves the floating
fruit or seed has many difficulties to contend with that considerably
restrict its capacities for distribution. Thus the seeds of Avona
palustris and of Carapa guianensis are very apt to germinate when
afloat in river-drift ; and my observations indicate that the germinat-
ing seed would soon be killed when it reached the sea-water, though
the dead seed might float a long time and be thrown up in a more
or less empty or unsound condition on some distant shore. So again
with Manicaria saccifera, the seeds do not seem to be able to with-
stand sea-water immersion for a long period, though the fruit with a
decaying or dead seed may be transported by the currents for a great
distance. Sacoglottis amazonica is rather better adapted in these
respects.

Drift supplied by the Plants of the Beach and its Borders. —
In the last place we will deal with the plants of the beach and its
borders that add their buoyant seeds and fruits to the drift of the West
Indian seas. Those which are most generally distributed, being
those which are most characteristic of the drift, are enumerated below.
In point of size the drift derived from beach plants in the West
Indies offers a great contrast to that supplied by the beach vegetation
of the tropical islands of the Indian and Pacific oceans. In the West
Indies we miss the large fruits of Barringtonia speciosa, Cerbera cdol-
lam, Ochrosia parvifloray Heritiera littoralis, Cycas circinalis^ Pandanus,
etc., trees that give character to the vegetation of the beaches of
many an island and many a tract of continental coast in those oceans.
The largest fruits of the common West Indian beach-drift, such as
those of the Manchineel (Hippomane mancinella), Thespesia populnea,
and Ecastaphylliim brownei, are not more than ij inches (37 mm.)
across ; and most of the other plants contribute seeds and seed-like
fruits varying from a sixth to three-quarters of an inch (4-18 mm.)
in size.

The Beach Plants commonly represented in the Floating
and Beach Drift of the West Indies.

(One or two of the plants, like Conocarpus erectus, are perhaps most
characteristic of the borders of the mangrove swamps, but since they
thrive also amongst the vegetation bordering the beach they are here
included.)

Canavalia obtusifolia (seeds).
Chrysobalanus icaco (stones).
Coccoloba uvifera (stone-like fruits).
Colubrina asiatica (seeds).
Conocarpus erectus (achenes).
Ecastaphyllum brownei (legumes).
Guilandina bonducella (seeds).
Hibiscus tiliaceus (seeds).
Hippomane mancinella (stones).
Ipomcea pes-caprce (seeds),
Sccei^ola plumieri (stones).

6 PLANTS, SEEDS, AND CURRENTS

Sophora tomentosa (seeds).

Suriana maritima (seed-like nucules).

Thespesia populnea (seeds liberated by the decaying fruit).
Tournefortia gnaphalodes (pyrenes).
Vigna luteola (seeds).

There are one or two trees typically represented in West Indian
beach-drift which ought to be mentioned, their fruits being carried
long distances by the currents, such as Terminalia katappa and Cassia
fistula. Both have been introduced from the Old World. The last
named is discussed at length on a later page. The first is dealt with
in my book on Plant Dispersal. It is a typical littoral tree of the
tropics in the eastern hemisphere ; and in the West Indies it is tend-
ing to escape from cultivation to find a home on the beach.

Cirripedes, Serpulce, and similar organisms, that have attached
themselves to floating drift, often enable one to distinguish the larger
seeds that have been brought from a distance before being stranded.
Where the plants concerned grow in the neighbourhood it is not easy,
as before remarked, to discriminate between the foreign drift and the
drift of local origin. The difficulties are well exhibited in an island
like Jamaica. The large seeds of Entada scandens are common on
the beaches of the north coast ; but the plant grows in the island,
and one cannot in the absence of incrusting shells of marine organ-
isms determine whether a weather-beaten seed lying on the beach
came originally from some neighbouring coast, such as from Cuba,
or whether it has acquired its weathered appearance from lying
exposed for a long period on the shore. On the other hand, the fruits
of Manicaria saccijera and Sacoglottis amazonica would be rightly
regarded as of foreign origin, since there is little probability of the
plants growing in the island.

The Sorting Influence of the Waves. — The waves often sort
out the finer beach-drift, and deposit it in a line above the larger and
heavier fruits and seeds which are usually mixed up with Sargasso
weed, drift-wood, and similar materials. Small pumice pebbles and
Spirilla shells mark the line of deposition of the smaller seeds and
fruits belonging to such plants as Hibiscus tiliaceusy Ipomoea pes-
caprce, Suriana maritima, Tournefortia gnaphalodes, Vigna luteola,
etc. It is, however, the larger drift that usually claims attention,
the smaller materials being often overlooked.

From my observations at St. Croix, Turks Islands, Grenada,
Tobago, Trinidad, Jamaica, and Colon, it is evident that the beach-
drift displays much the same general characters over the West Indian
region. At the same time in addition to the seeds and fruits that
are found on most of the coasts, whether insular or continental, each
locality often presents some peculiar feature. Thus on the Colon
side of the Panama Isthmus there are to be found on the beaches the
large fruits of Prioria copaifera and empty palm fruits of Astrocaryum,
etc. In Jamaica we find the fruits of Gria^ cauliflora ; and in Trinidad
the ordinary seeds and fruits of the drift are often masked by the
large amount of strange fruits and seeds brought down by the Orinoco
and stranded on its south coast.

WEST INDIAN BEACH-DRIFT

7

Method of Identifying the Constituents of the Driit. — My
previous experience of the seed-drift of the islands of the Pacific and
more especially of the American borders of the ocean, as in Ecuador
and at Panama, had made me familiar with many of the constituents
of West Indian drift. On the other hand, my later West Indian
experiences helped me to identify constituents in the drift on the
Pacific coasts that I had not before recognised. The method em-
ployed was to search for the parent plant. In some cases a long
time passed, as in that of Dioclea reflexa, before success crowned my
efforts. This plant is of particular interest, as it is one of the few
possessing seeds that are transported by the Gulf Stream in a sound
condition to the shores of Europe. Ultimately I tracked it to one of
its homes in the mountains of Grenada, and one of my chief objects
of making a sojourn of some weeks in that locality was to investigate
the conditions that led to its supplying its seeds to the drift.

The same plan was followed in Jamaica whenever I came upon
some new seed or fruit on the beaches. With the aid of my coloured
companions, who were very zealous in helping me to find its source,
it was often not very difficult. Thus it was not long before I found
the parent plants of the Anchovy tree (Grias caulifiora) and of the
large seeds of the Antidote Vine {Fevillea cordifolia) so common on
beaches in the Black River district.

Certain seeds and fruits common in the Jamaican drift eluded
my efforts in this direction, and usually because the plants did not
grow in the island. Two conspicuous offenders in this way were the
fruits of Sacoglottis amazonica and Manicaria saccifera, two of the
most interesting components of West Indian beach-drift. However,
I was introduced to them by the late Mr. Hart of Trinidad. The
source of the fruits of the first named was for a long time unknown,
and Mr. Hart played a prominent part in the inquiry that led to their
identification. Though not Jamaican, both are included in the
Trinidad flora, growing mostly as I learnt in the swamps on the
south side of the island. But as found on the Trinidad beaches the
fruits often display evidence of long flotation in the sea in the marine
organisms incrusting them. They have their chief home in the swamps
of the Amazon and the Orinoco, and many of the fruits found in the
Trinidad and Tobago beach-drift are doubtless thence derived.
It was the presence of these fruits of Manicaria and Sacoglottis on the
beaches of the south coast of Jamaica that long ago led Sir D. Morris
to recognise an element of drift hailing from the Orinoco and the
Amazon, a subject dealt with in connection with Jamaican beach-
drift in a later page.

Orinoco and Amazon Drift distributed over the West
Indian Region. — " Orinoco drift " is a term often on the lips of
residents in Trinidad, Tobago, and Grenada. They apply it to all
the drift brought by the Equatorial Current, much of which must
conie from the Amazon as well as from the shores of Brazil and of the
Guianas. Most of this drift finds its way into the Caribbean Sea
between Barbados and the Spanish Main, either entering the Gulf
of Paria and emerging through the Bocas, or floating through the
passages separating Trinidad, Tobago, and Grenada. As indicated

8 PLANTS, SEEDS, AND CURRENTS

by the bottle-drift data, to be dealt with in a later chapter, most of
the vegetable drift carried by this current would be borne across the
Caribbean Sea in the direction of the coasts of Honduras. The
materials that escaped being stranded on the shores of Central
America or on the south coast of Jamaica, on the Cayman Islands,
and on the south-west shores of Cuba, would be carried through the
Straits of Yucatan into the Gulf of Mexico, some portion being
beached on the shores of that gulf, the remainder ultimately reaching
the Straits of Florida.

Reference will subsequently be made to several bottles that have
accomplished this passage in part, and to others that have done so
in its entirety. Occasionally one of them stranded on the beach tells
the story of the seed-drift lying around it. Thus, a bottle from Ceara
on the north coast of Brazil, which Mr. Savage English mentions as
cast up on Grand Cayman, clearly demonstrates the part played
by the Equatorial Current in carrying drift to the Cayman Islands.
" The quantity of living seed afloat at this western end of the Carib-
bean Sea " (thus he writes in the Kew Bulletin, 1913) " must be
immense, for it is hardly possible to examine more than a few feet of
the windward beaches of Grand Cayman without finding a seed of
some sort ; leguminous, probably, if it is not one from a Manicaria
palm, though there are plenty of others."

The Mode of Distribution of Orinoco and Amazon Drift. —
Although the main track of the Orinoco and Amazon drift is chiefly
restricted to the southern part of the West Indian region, any differ-
entiation that the Equatorial Current might effect in the distribution
of littoral plants, as it pursues its westerly course across the Caribbean
Sea, would be obliterated by time. The usual variation of the winds
between north-east and south-east would often bring about the
deflection of the floating drift ; and we get cases like that of Jamaica,
which receives some of the drift brought by the Equatorial Current
on its southern shores and a quantity of Cuban and Haitian drift
on its northern coasts during the prevalent north-easterly winds.
Over most of the West Indian region outside the direct influence of
the Equatorial Current there is a prevailing north-westerly and
westerly set of the surface waters ; and it is in this manner that the
beaches of the Turks Islands are often piled up with drift from San
Domingo, Porto Rico, and the Leeward Islands.

The Turks Islands and their Suitability for the Study of
Seed-drift. — Though the prevailing winds in the Turks Islands are
easterly, north-westerly winds occur at times in the winter months
when different climatic conditions reign and the routine of the year
is reversed for man, beast, and plant. The lee or protected sides of
the islands for the greater portion of the twelve months now become
the weather sides. At such times, when the sea breaks heavily on
the shores, steamers cannot land either passengers or cargo, and
proceed on their course to Haiti or Jamaica, or run for protection to
the " Hawk's Nest," the name of the anchorage off the southern
extremity of Grand Turk. Boats cannot ply between the islands,
and communication is interrupted for days together when the weather
is bad. Small craft accustomed to beat back from the islands to

WEST INDIAN BEACH-DRIFT

9

leeward now set their sails to the fair wind and accomplish in a few
hours a passage that generally occupies days. At these times the
stranding of drift on the eastern sides of the cays is suspended, and
the drifting seed is beached on the western shores. This is an example
of what must happen over much of the West Indian region when
Nature for short periods breaks through her regime and quite different
climatic conditions assert themselves. It will thus be understood
how time would in the end prevent any marked differentiation in
the distribution of littoral plants in the West Indian region.

For a satisfactory study of the West Indian beach-drift it was neces-
sary to find a place where the local flora could be largely excluded
as a probable source of materials. In Jamaica, for instance, it was
apparent that much of the beach-drift could have been furnished by
the plants of the island ; and often the only indications of a foreign
origin were the signs of long immersion in the sea afforded by in-
crusting Ser puke, Balani, Polyzoa, etc., and by the borings of molluscs.
But most of the stranded seeds did not display these evidences of
a long ocean journey; and in such cases one could rarely be sure of
one's ground.

This was one of the reasons why I selected the Turks Islands at the
south-eastern end of the Bahamas for a more thorough examination
of West Indian seed-drift. Almost all of the larger fruits and seeds
that are stranded on the eastern beaches of the various islands or
cays, making up this little archipelago, belong to plants that are not
only absent from this small group, but are not included in the
Bahamian flora. The flora of the Turks Islands, which I have dealt
with briefly in Chapter XII., is largely littoral in character, almost
entirely Bahamian in composition, and as such displays a combined
West Indian and Florida facies.

Author's Indebtedness to Dr. Millspaugh. — Having the good
fortune to meet Dr. Millspaugh on Grand Turk, I thus acquired more
precise notions of the relation between the stranded drift and the
plants of this archipelago. Dr. Millspaugh very kindly lent me the
manuscript of the Flora of the Bahamas, by Dr. Britton and himself.
From its pages I obtained a general idea of the Bahamian flora, to
which the plants of the Turks Islands belong. This generous loan
of a work before its publication, a work representing the results of
years of exploration and research, was quite spontaneous, and I
shall always take a keen pleasure in recalling the circumstance. Its
perusal enabled me to approach the subject of the relation between
the plants represented in the beach-drift and the plants of the flora
of the Turks Islands with far greater confidence than I should have
otherwise possessed.

But in another way the author is deeply indebted to the labours
of the American botanists. One of the most methodical examinations
hitherto made of the vegetation of the sand-islets of a coral-reef region
was carried out in 1904 by Mr. O. E. Lansing in the sand-keys lying
to the westward of Key West, Florida. He was commissioned by
the Field Columbian Museum of Chicago ; and his collections, com-
prehensive notes, and maps form the subject of a paper on the
Flora of the Sand-Keys of Florida, by Dr. Millspaugh in the publiea-

10 PLANTS, SEEDS, AND CURRENTS

tions of the same institution (Bot. Ser. 1907). A discussion of this
paper is given in Note 7 of the Appendix. I may remark that the
Florida key " is the equivalent of the Bahamian '* cay," and
that both terms will be employed here in their respective associations.

The beach plants of the Turks Islands, which in the smaller cays
occupy much of their surface, are, as a rule, common West Indian
species and are generally distributed through the Bahamas, occurring
also in the Florida keys.

The Stranded Drift of the Turks Islands. — The mangrove
formation, which is still fairly extensive in area on Grand Turk in
spite of the salt-making industry, is very limited in its composition,
and lacks most of the accessory plants that give variety to the great
mangrove formations of the large West Indian Islands. In its
restricted composition and in its constituent trees (Rhizophora mangle^
Laguncularia racemosa, Avicennia nitida, with Conocarpus erectus at
the borders) the mangrove belt of the islands of the Turks Group
approaches very closely that of the Florida Keys. So abundant is
the foreign drift on the beaches of the cays of the Turks Group that
the seeds and fruits of the local mangrove and beach plants scarcely
figure in it. Here we shall be concerned only with the larger stranded
seeds and fruits from other regions. The smaller and local drift is
discussed in Note 2 of the Appendix.

During my sojourn of three months in the Turks Group I visited
all the islands or cays, and collected or recorded about 2000 foreign
seeds or fruits, all of them doubtless derived from the islands to the
southward and eastward, San Domingo, Porto Rico, and the Leeward
Islands. In Note 13 of the Appendix it is shown from the indica-
tions of bottle-drift stranded on the south-eastern Bahamas, and from
the course taken by bottles dropped into the sea in this neighbour-
hood, that the prevailing set of the surface currents in this region
is in a W.N.W. direction, and that the Turks Group lies in the track
of drift on its way in the Antillean Stream from the islands to the
eastward and southward to the Florida Straits, where it gets within
the influence of the Gulf Stream.

The analysis given below illustrates the relative frequency of the
several kinds of seeds and fruits that figure in the beach-drift. As
above remarked the local seed-drift is derived from plants growing
in the vicinity, whether in the mangrove swamps or on the sandy
beaches, the present discussion being almost exclusively restricted
to the seeds and fruits of plants not growing on the islands, the local
materials being largely disguised by the mass of drift from a distance.

There are, however, named in this list the seeds of Guilandina
bonducella, which grows in the larger islands of the Turks Group away
from the iDcach. But since these drift seeds were best represented
on Greater Sand Cay at the southern end of the group, a cay which
does not possess the parent plant but is the first to receive the foreign
drift, it is apparent that they must be included in the list.

Some of the drift is washed into the interior of the cays during
hurricanes, and may be found between the sand-hills a hundred
yards and more from the beach. It will be noticed in the following
table that more than half of the foreign seeds and fruits stranded

WEST INDIAN BEACH-DRIFT 11

on the beaches of the Turks Islands would be able to reproduce the
plant.

Table Showing the Constituents op the larger Drift Stranded on the
Eastern Shores of the Turks Islands, all being of Foreign Origin.

(The numbers illustrate their relative frequency. Leguminous plants are marked
L, and palms P. Further details respecting distribution, station, and other matters
will be found on the pages indicated.)

Fruit (F)

Number

Pages for

or

per

Condition of Seed

further

Seed (S)

Thousand

Details

L. Ecastaphyllum (?)

F

200

Decaying or decayed .

111

Spondias lutea .

F

200

Usually sound ....

111

Hippomane mancinella

F

110

113

Terminalia katappa

F

108

116

L. Entada scandens .

S

100

117

L. Mucuna urens (and an

allied species) .

S

60

120

Fevillea cordifolia .

S

50

5% apparently sound .

124

P. Manicaria saccifera

F

40

2% sound

127

L. Dioclea reflexa .

s

14

130

Sacoglottis amazonica .

F

14

A few fruits with sound

133

L. Guilandina bonducella

s

10

138

L. Hymenaea courbaril .

F

10

Some seeds sound .

140

Carapa guianensis .

Q
O

1 n

lU

10% appear sound

1/11

Mammea americana .

F

6

Germinative capacity

144

Crescentia cujete .

F

4

Dead

145

Crescentia cucurbitina .

F

2

Dead

147

L. Andira inermis

F

3

Germinative capacity

150

L. Cassia grandis .

F

3

A third of the seeds sound

152

L. Cassia fistula

F

2

A sixth of the seeds sound

152

Calophyllum calaba

F

2

Decaying or decayed .

155

Sapindus saponaria

s

2

Not examined ....

156

L. Drepanocarpus lunatus

F

1

159

Omphalea diandra.

s

1

Germinative capacity

159

P. Acrocomia ....

F

1

Fruits empty ....

160

Ipomcea tuberosa .

S

1

161

Mangifera indica .

S

46

164

1000

We find washed up on the weather beaches of the Turks Islands
almost all the larger fruits and seeds that are characteristic of the
beach-drift over the West Indian region ; and they are all the more
mteresting in these islands because, with few exceptions, they are
foreign to the local flora.

Jamaican Beach-drift. — Almost all of them came under my notice
in the beach-drift of the coasts of Jamaica. Amongst the exceptions
are the seeds of Carapa guianensis and the pods of Hymencea courbaril.
The first named, however, were included in a collection of Jamaican
beach-drift sent by Mr. Morris (afterwards Sir D. Morris) to Kew
about thirty years ago, the contents of which are given in the list

12

PLANTS, SEEDS, AND CURRENTS

appended. But this list is only partly illustrative of Jamaican drift,
and principally of the larger fruits and seeds. To supplement it we
should have to add many of the names of the beach plants con-
tributing regularly to West Indian stranded drift which are given
in the list on page 5, such as Canavalia ohtusifolia, Chrysohalanus
icaco, Coccoloba uvifera, Conocarpus erectus, Hippomane mancinellay
Sophora tomentosa, Thespesia populnea, etc. ; and besides there would
be the mangroves (Rhizophora, Laguncularia, Avicennia) already
discussed in this chapter, as well as Mammea americana, Grias
cauliflora, etc. All the seeds and fruits most typical of West Indian
beach-drift may be found on the coasts of Jamaica. But the point
with which we are more immediately concerned here is that almost
all the larger foreign drift stranded on the Turks Islands can be found
on the Jamaican beaches.

List of Seeds and Fruits washed Ashore at the Palisadoes
Plantation on the South Coast of Jamaica, being a Collection

SENT TO KeW by Mr. MoRRIS ABOUT 1884, AND DESCRIBED BY

Mr. Hemsley in Part IV. of his Work on the Botany of the
" Challenger " Expedition (1885).

The localities in which the different seeds and fruits have been
found by me in the West Indian beach-drift are indicated by abbre-
viations explained below. The drift specimens not named by Mr.
Hemsley but since identified are marked *.

Calophyllum calaba. Tur., Jam.
*Sacoglottis amazonica. 2'ur., Jam.^ Trin., Col.

Carapa guianensis. Twr., Trin.

Spondias lutea. Tur., Jam., Trin., Col.
*Dioclea reflexa. Tur., Jam., Trin.

Mucuna urens. Tur., Jam., Trin., Col.

Mucuna sp. Tur., Jam., Trin.

Ecastaphyllum brownei. Jam., Col.

Guilandina bonduc.

Guilandina bonducella. Tur., Jam., Trin.
Cassia fistula. Tur., Trin.
Dimorphandra mora. Trin.
Entada scandens. Tur., Jam., Col.
Fevillea cordifolia. Tur., Jam., Trin.
Ipomoea pes-caprae. Tur., Jam., Trin., Col.
*Ipomoea tuberosa. Tur., Jam.
Omphalea diandra. Tur., Trin.
Juglans sp. Trin.

Manicaria saccifera. Tur., Jam., Trin.
Astrocaryum sp. Trin., Col.

Under their respective headings in a later part of this work will be
found the accounts of the identification by Sir D. Morris and by
Mr. Hemsley of the fruits or seeds of Sacoglottis and of Ipomoea
tuberosa. The seeds of Dioclea reflexa are included in the Morris
collection in the Kew Museum.

WEST INDIAN BEACH-DRIFT

18

Explanation of the abbreviations. — Tur. = Turks Islands ; Trin. =
Trinidad and the adjacent islands of Tobago and Grenada; Jam. =
Jamaica; Col. = Colon.

Note. — Further details concerning the condition in which the seed
and fruits occurred in the drift and other particulars will be found
on the pages shown in the index.

Beach-drift of Trinidad and the Neighbouring Islands of
Tobago and Grenada. — In the same way almost all the larger
fruits and seeds most frequent in the beach-drift of the Turks Islands
came under my notice on the beaches of Trinidad, Tobago, and
Grenada. An important exception existed in the seeds of Entada
scandens, a plant that is not a member of the floras of this part of the
West Indian region, and is seemingly absent from those of the district
of the Amazon and the Orinoco. Together with much strange drift
on these beaches I found the fruits and seeds of Carapa, Cassia,
Crescentia, Dioclea, Fevillea, Hippomane, Mammea, Manicaria,
Omphalea, Mucuna, Sacoglottis, and Spondias named in the Turks
Islands list. Fruits of palms are also frequent, including those of
Astrocaryum and Bactris, the last probably derived from the palms
growing in the coastal swamps of the locality.

But on the Trinidad and Tobago beaches occurs much drift that
is strange to the West Indian region, and is evidently derived from the
Orinoco district as well as from the rivers of the Guianas and from the
valley of the Amazon. Amongst the leguminous seeds are those of
a species of Mucuna, 1 J inches across (its incrusting marine organisms
often telling a story of a long sea-passage), and the seeds of a species
of Guilandina unknown to me from elsewhere. References to the
seeds of these plants will be found later. But there is much of the
strange drift piled on the south coasts of Trinidad that would
not withstand long immersion in the sea. This is certainly true of
a remarkable fruit which, as Prof. Pax informs me, seems to be a
species of Hippocratea ; but several of the other fruits and seeds
have not been identified.

Amongst the unusual objects thrown up on the coasts of Trinidad
are the huge brown embryos, three to four inches long and bare of
coverings, of Dimorphandra mora, a common leguminous forest tree
of British Guiana and also a native of this island. I was not aware
of their identity until I recognised them in the Kew Museum. Accord-
ing to Hemsley the embryo of this tree is one of the largest in the
vegetable kingdom (Chall. Bot., IV., 301). An empty pod was in-
cluded in the Morris collection of Jamaican beach-drift. These
naked seeds are of a very tough, durable nature ; but it seems scarcely
likely that they would retain their vitality after prolonged flotation
in the sea.

Another singular woody fruit, top-shaped, deeply grooved, and 2J
inches in size, is identical with a fruit which is named Juglans jamai-
censis in the drift collection of the Kew Museum, and is perhaps the
one referred to by Hemsley under ^Tuglans with a query in his account
of the Morris collection (Ibid., IV., 303).

Drift on the Colon Beaches. — Much of the larger drift that is

14 PLANTS, SEEDS, AND CURRENTS

common to Trinidad, Tobago, Grenada, the Turks Islands, and
Jamaica was observed by me at Colon on the extreme western border
of the Caribbean Sea. On these beaches occurred the fruits and
seeds of Hippomane mancinella, Manicaria saccifera, Mucuna urenSy
Sacoglottis amazonicay Spondias lutea, etc. Reference has already
been made to one or two of the peculiar features of the beach-drift
on the Colon side of the Panama Isthmus.

The Absentees from the Beach-drift of the Turks Islands. —
It is thus evident that most of the larger foreign drift of the Turks
Islands is to be found on the beaches throughout the West Indian
region. But the beach-drift of this small group does not contain all
the larger fruits and seeds that in one locality and another are charac-
teristic of West Indian drift ; and we shall see that their absence is
significant of the weeding-out or exclusion of the drift least fitted for
the accomplishment of the transatlantic passage, of which the Turks
Islands represent the end of an early stage. For instance, it lacks
the fruits of Grias cauliflora which are so characteristic of Jamaican
beach-drift and are probably confined to that part of the West Indies.
It lacks also the pods of Ecastaphyllum brownei, which form a common
feature in the stranded drift of Jamaica and doubtless also of Cuba,
as well as of the Caribbean side of the Panama Isthmus, as at Colon.
Neither of these drift fruits seem to have been recorded from the
stranded drift on the western shores of Europe, nor are they likely
to be found there ; and their absence from the beaches of the Turks
Islands is an indication of their unfitness for the ocean traverse. Nor
do we find thrown up on the beaches of this outlying West Indian
group several of the strange fruits stranded with much other Orinoco
drift on the south coast of Trinidad, and doubtless not possessing
great floating powers.

Generally speaking (it may be added) I found nearly all the drift
seeds and fruits on the Turks Islands beaches that my previous
experience in other parts of the West Indies led me to expect. An
exception, however, which is concerned with the absence of the empty
fruits of Astrocaryum, a genus of palms, is dealt with on page 181,
but it is highly probable that I overlooked them, since their occur-
rence on the beaches of the Azores implies great capacity for transport
by currents, though in an ineffective state.

Oceanic Drift in Transit represented on the Beaches of
the Turks Islands. — Since in this small group the local flora can
be readily excluded, we are here presented with oceanic drift in
transit. The drift here stranded is something more than a sample
of the material that is for ever being drifted in the Antillean Stream
westward and northward past and through the Bahamas towards
the Florida Straits, where the Gulf Stream concentrates its energy
before proceeding to traverse the North Atlantic. It represents the
residue of all the vegetable debris (fruits, seeds, bark, leaves, branches,
tree-trunks, etc.) brought down to the sea by the rivers, or carried off
by the currents from the shores, of the large islands lying to the
southward and eastward. Since much of this material possesses
limited floating powers, it would go to the bottom in a short time.
After drifting about for weeks or months the mass of vegetable debris,

WEST INDIAN BEACH-DRIFT

15

once very large, now very small, reaches the Turks Islands at the
south-eastern extremity of the Bahamas. Depositing on those small
islands a sample of its contents, it continues its drift westward and
northward towards the last starting-point of the swift current of
the Gulf Stream in the Straits of Florida before it begins the Atlantic
traverse.

How truly the sample represents the seeds likely to be drifted
across the Atlantic is shown in the fact that practically all the seeds
and fruits known to me as having been stranded on the coasts of
Europe occur in the drift of the Turks Islands, making up as much as
a third of the total. A list of them is given in the following chapter.
We are thus able to detect at a glance the larger seeds and fruits
of the drift which are most likely to accomplish the traverse of the
North Atlantic without loss of the germinative capacity. The results
obtained in the Turks Islands therefore fully justified my selection
of this locality for the observation of Nature's method of sifting the
drift of the West Indian region before it gets within the influence
of the Gulf Stream in the Florida Sea.

The Black River of Jamaica as a Source of a Drift. — As an
example of the manner in which rivers convey seeds and fruits to
the sea in the West Indian region, I will take the case of the Black
River, the largest river in Jamaica. Above the mangrove belt of
Rhizophora mangle, Laguncularia racemosa, and Avicennia nitida,
all of them trees that contribute to the floating drift, one passes into
a region where the Anchovy Pear (Grias cauliflora) is the most con-
spicuous tree on the riverside, its large germinating fruits frequently
floating past in the stream. Although in places taller trees closely
line the river, it is the Anchovy Pear with its terminal head of large
leaves, four or five feet long, and its flowers and fruits growing from
the simple straight trunk, that first catches the eye. One of the
loftier trees is the Paki tree (Crescentia cucurbitina), with its gourds
hanging suspended over the water and often to be noticed floating
down the river. A Crinum flourishes at the water's edge, its large
fleshy seeds frequently occurring in the germinating condition in the
floating drift. Here and there, hanging in leafy festoons from the
tree branches as they spread over the water, is the Antidote Vine
(Fevillea cordifolia), which with Grias cauliflora may be regarded as
amongst the most interesting plants at the riverside. Its large fruits,
like cannon-balls, were occasionally to be seen afloat. The Hog
Gum tree {Symphonia globulifera), one of the Guttiferae, grows also
on the banks, its large germinating seeds floating in numbers in the
stream.

Beyond the lower wooded district at the riverside, one passes into
an open savannah-like region, much of which is swamp. It is known
as the Great Morass, and is the home of the alligator. A reed-like
growth of Typha, Papyrus-like Cyperi, and other tall sedges, which
add little or nothing to the floating seed-drift, lines the banks;
whilst clumps of Grias trees decked with Ipomoeas occur at intervals
by the water-side. In this open country, in places where the ground
is rather drier, one notices on or near the banks various trees that are
represented by their fruits or their seeds in the floating drift, such as

16 PLANTS, SEEDS, AND CURRENTS

Paritium {Hibiscus) elatum, Crescentia cujete (Calabash tree), and the
Angeleen tree (Andira inermis). For miles inland this swampy plain
extends. Above Lacovia the hilly country is entered, the banks
steep and the slopes well wooded. Here reappear the Anchovy
Pear tree, the Antidote Vine, the Angeleen tree, and Paritium
elatum ; and amongst other trees occurs Crudya spicata, the large
seeds of which, often as large as those of Entada scandens and possess-
ing the same name of " Cocoon," may be observed floating in numbers
in the germinating condition in the stream. Amongst the tall trees
on the steep slopes grow Cassia grandis, the long pods of which occur
in the floating drift, and a species of Ficus, the fruits of which could
only float for a short time ; whilst Mucuna urenSy a climber on the
trees, adds its seeds to the floating drift.

I have mainly referred to the vegetation that contributes to the
floating drift of fruits and seeds carried by the stream. The clumps
of tall Sabal palms (S. umbraculifera), that dot the surface of the
Great Morass, make little or no addition to the drift, as the fruits
possess but slight buoyancy, and the same may be said of other palms
(Euterpe, etc.). The same remark applies to the climbing aroids
(Syngonium and Philodendron) that often conceal the tree-trunks.

But brief reference need here be made to a multitude of aquatic
and subaquatic plants, Ceratophyllum, Nymphcea, Pontederia, Pota-
mogeton, Sagittaria, Utricularia, etc., that, except in the fourth and
fifth cases, were not represented by their seeds or their fruits in the
floating drift. In the lower part of the river the floating seed-drift
often accumulates amongst the patches of Water Hyacinth {Ponte-
deria), and here may be found the Water Lettuce (Pistia) and
portions of Azolla. In concluding these remarks on the Black River,
I may call attention to the frequency of germinating fruits and seeds
in the floating drift, as already noticed in the cases of Crinum, Crudya,
Grias, and Symphonia.

In the foregoing remarks the Great Morass of the Black River
district is dealt with as a source of river-drift. A detailed description
of it will be found in Chapter V. ; and there also will be found an
account of the Great Morass of Westmoreland in the south-west part
of the island. The Cabarita, one of the larger rivers that drain it,
presents most of the characters of the Black River as regards vegeta-
tion, though on a smaller scale. As will subsequently be shown,
many of the conspicuous features of the Black River Morass are
represented in the portion of the Great Morass of Westmoreland
that extends westward from Savanna-la-mar to Negril, Grias cauli-
flora being especially prominent on the banks of streams in this
part of the island.

The Roaring River Falls, Jamaica. — At these falls on the north
coast of Jamaica there are some fine specimens of the Grias tree,
which grows not only near the brink of the falls, but half-way down
the precipitous slopes of calcareous tufa that form their face. At
the cost of a wetting I clambered down the steep slopes to their base.
Fruits carried over the falls have caught in crevices in their descent,
and there germinating have developed into trees. Below the falls
the Grias trees are associated with tall trees of Bucida buceras and

WEST INDIAN BEACH-DRIFT

17

Crescentia cucurbitina. Prof. Harshber^rer, who visited this, locality,
refers to the Bucida and Grias trees (Phyt. Surv. N. Amer., p. 678).
The " olive tree," as the Jamaicans name Bucida buceras, ifi a charac-
teristic swamp tree of the estuaries on the north side of the island.
Owing to the lack of mature fruits the opportunity of studying this
interesting tree from the standpoint of dispersal was not presented
to me.

Comparison of the Beach-drift on the Pacific and West
Indian Coasts of Tropical America. — A few remarks may here
be made on the small contrast that exists between the beach-drift
on the Pacific coasts of tropical America and on the West Indian
or Caribbean side. As discussed in the case of the Ecuadorian and
Panama beach-drift in my book on Plant Dispersal (p. 498), many of
the familiar mangrove and beach plants occur on both sides of the
continent and add their fruits and seeds to the drift, such as Rhizo-
phora mangle, Laguncularia racemosa, Avicennia nitida, Canavalia
obtusifolia, Co?iocarpus erectus, Ecastaphyllum brownei, Hibiscus
tiliaceus, Hippomane mancinella, Ipomoea pes-caprce, etc. To these
may now be added Sccevola plumieri, a characteristic West Indian
strand shrub that occurs also on the Pacific coasts.

Equally common on the beaches of the West Indies and Colon on
the Atlantic side and of Ecuador and Panama on the Pacific side
are the seeds of Entada scandens and Mucuna urens and the fibrous
" stones " of Spondias lutea. Much of the drift found afloat in the
estuaries on the Pacific coast could be matched in those of the West
Indian region, since many of the estuarine and swamp plants are the
same. If we supplement the account given in my previous work of
the drift carried down to the sea by the Guayaquil River in Ecuador
with the names of two floating fruits not there identified, namely,
the gourds of Crescentia cujete and the fruits of Grias cauliflora, we
emphasise the resemblance between the character of the drift carried
into the Pacific Ocean by the Ecuadorian rivers and of that dis-
charged into the Caribbean Sea by the Black River in Jamaica.
Amongst the beach-drift gathered by me on both sides of the Panama
Isthmus were the large pods of Prioria copaifera, as identified at
Kew. They seem to be quite useless for dispersal by currents,
since the seeds of the fruits examined were always decayed. This is
the type species of a genus which was first described by Grisebach
(p. 215) from a rare Jamaican tree.

There are, however, differences between the drift found on the
Pacific and Atlantic sides. Thus since neither Manicaria saccifera
nor Sacoglottis amazonica occur on the Pacific border of the conti-
nent, their fruits have not been found in the drift. Here the empty
seeds of the Vegetable Ivory palm, Phytelephas macrocarpa, con-
stitute one of the principal features of the floating and stranded drift
of coasts and estuaries in Ecuador, the sound seeds possessing no
floating power. It is remarkable that this palm which abounds on
the banks of the Magdalena River does not contribute to West Indian
drift. We learn from Spruce's Notes of a Botanist on the Amazon
and in the Andes that the Eastern and Western Andes possess in each
case a separate species of the genus,
c

18 PLANTS, SEEDS, AND CURRENTS

Summary

1. After remarking that beach-drift has much the same general
characters over the West Indian region, it is pointed out that its
principal sources are the plants of the beach, of the coastal and
estuarine mangrove swamps, and of the riverside in inland districts

(p.i).

2. Whilst the beaches near an estuary in a large island are the most
suitable localities for the drift in the mass, it is in the low islet lying
far out to sea that we find the best opportunity of investigating the
portion of it that is most fitted for oceanic transport. Such an islet
receives only the residue of a vast amount of vegetable debris which
for the most part soon goes to the bottom (p. 2).

3. The distinction is drawn between local and foreign beach-drift,
the latter which is derived across the sea from other islands being
likely to be masked by the local materials (pp. 2, 3).

4. As illustrating the part taken by rivers above the mangrove-
lined estuary in supplying drift to the beaches, the Black River of
Jamaica is taken as an example; and it is shown that on account
of the tendency to germinate when afloat many of the seeds and fruits
of riverside plants have little or no effective value for over-sea dis-
tribution (p. 3). In others again the floating power is either absent
or slight; whilst there may be cases where the buoyancy is great,
but the seeds have a fleeting vitality and soon decay. The con-
clusion is formed that not one-fifth of the seeds and fruits brought
down by a West Indian river from inland districts to the sea would
be capable of reproducing the plant after a traverse of a hundred
miles of ocean (pp. 4, 5).

5. The mangrove formation as a source of drift is next discussed.
It is shown that whilst the true mangroves (Rhizophora, Laguncu-
laria, Avicennia) are in one form or another well adapted for over-
sea transport, in the case of their associates {Anona, Carapa, Mani-
caria, Sacoglottis, etc.) the floating seed or fruit has many difficulties
to contend with, which considerably restrict their capacities for
effective distribution by currents (pp. 4, 5).

6. Then the plants of the beach-borders are dealt with from the
same standpoint, and a list is given of West Indian beach plants
commonly represented in the drift. It is remarked in passing that
in their much smaller size the fruits of West Indian beach trees offer
a great contrast to those of the trees of the far more luxuriant beach
vegetation of the tropical islands of the Indian and Pacific Oceans
(pp. 5, 6).

7. The difficulty in discriminating between local and foreign drift
is again alluded to, and reference is made to the sorting out by the
waves of the finer and larger components of the beach-drift (p. 6).

8. Whilst fresh emphasis is laid on the uniformity in general
characters of the beach-drift of the West Indian region, it is shown
that each locality may present some peculiar feature (p. 6).

9. The author then refers to his method of identifying the con-
stituents of the drift (pp. 7, 8).

10. The distribution over the West Indian region of the seeds and

WEST INDIAN BEACH-DRIFT

19

fruits broujrht north from the estuaries of the Orinoco, the Guiana
rivers, and the Amazon is diseussed (p. 7).

11. Reasons are given for the bcUef that however uniformly
surface currents seem to act in distributing the seeds and fruits of
httoral plants in this region, Nature in the course of ages breaks
through her regime frequently enough to prevent any marked differ-
entiation in the distribution of littoral plants (p. 8).

12. The author then deals with his selection of the Turks Islands
at the south-eastern extremity of the Bahamas for the methodical
investigation of the drift fruits and seeds best adapted for oceanic
transport, one of the principal reasons being that here it would be
easy to exclude the drift of local origin. The results proved the
correctness of this surmise, since almost all the larger fruits and seeds
in the beach-drift of these islands belong to plants that are strangers
to the Bahamas (p. 8).

13. A detailed account of the drift stranded on the Turks Islands
is given, with a tabulated analysis showing the relative frequency of
the constituents of the foreign fruits and seeds, and the conclusion
is formed that almost all that are characteristic of West Indian drift
have been carried there by the currents (p. 10). In confirmation
of this conclusion a comparison is made with the beach-drift of
other West Indian localities, such as Jamaica (p. 11), Trinidad (p. 13),
etc.

14. The beach-drift of the Turks Islands is thus considered as
representing oceanic drift in transit. After drifting about for weeks
or months the mass of vegetable debris, once very large, now very
small, reaches this group. Depositing on these small islands a
sample of its contents, it continues its passage in the Antillean
Stream towards the Florida Straits, where the Gulf Stream gathers
its energy before commencing its Atlantic traverse. How truly the
sample represents the materials likely to be drifted across the Atlantic
is shown in the fact that one-third of the fruits and seeds that figure
in the foreign drift of the beaches of the Turks Islands have been found
stranded on the coasts of Europe (p. 14).

15. A more detailed description is given of the vegetation of the
Black River as a source of drift (pp. 15, 16); and the chapter is con-
cluded with a comparison of the beach-drift on the Pacific and Carib-
bean sides of tropical America, in which it is shown that although
there is a close resemblance in general composition there are important
differences in details (p. 17).

CHAPTER II

WEST INDIAN DRIFT ON EUROPEAN SHORES

In order to give point and method to my numerous observations
on the dispersal of plants by currents in the West Indian region,
as illustrated by the examination of the beach-drift and by various
buoyancy experiments, I will at first let the discussion centre around
the fact that some of the materials reach the shores of Europe.

The Literature of the Subject. — Although it is not possible
for me to deal exhaustively with the numerous references to the
occurrence of West Indian seeds and fruits on the coasts of Europe
which have been made since De I'Escluse, better known under the
Latinised appellation of Clusius," first figured some of them, in ignor-
ance of their origin, in his Exoticorum Lihri in 1605, the history of the
subject will be found treated with some detail in this chapter. Those
curious in the matter will find an excellent general account of our
knowledge up to the middle of last century in Dr. Gumprecht's
Die Treibproducte der Stromungen in Nordatlantischen Ocean (1854).
His object was to sum up the evidence supplied by the variety of
natural products from tropical regions thrown up on the north-west
coasts of Europe in favour of the extension of the Gulf Stream into
high northern latitudes, a theory that had been vigorously opposed
by Rennell and others. It is difficult for us to realise that such a
necessity ever existed. Yet it did ; and one result was the publica-
tion of this paper in the Zeitschrift fiir Allgemeine Erdkunde on the
drift-materials transported by the North Atlantic currents, in which
almost all the facts then known were gathered together and discussed
with the usual German acumen and thoroughness.

The subject of the West Indian drift on European beaches was
dealt with by numerous writers during the last century in their
treatment of the currents of the North Atlantic. Amongst them may
be mentioned Humboldt in his Voyage aux regions equinoxiales,
Paris, 1807, etc. ; Sartorius von Waltershausen in his Physisch-
geographische Skizze von Island, 1847 ; Schjoth in his work on different
marine phenomena {Om enkelte af Havets Phdnomene, Christiania,
1848); Irminger in his paper on the ocean currents (Zeitsch. fiir
Allgem. Erdk. 1854) ; Fogh in a paper on the Gulf Stream in Tidds-
skrift for populcere Fremstillinger af N aturvidenskaben, Copenhagen,
1857, where he gives a sketch of the history of our acquaintance
with the subject ; Vibe, chief of the Norwegian General Staff Survey,
in his Kusten und Meer Norwegens, published in a supplementary
volume of Petermann's Mittheilungen (1859-61); and Kohl, who in

20

WEST INDIAN DRIFT ON EUROPEAN SHORES 21

his Geschichte des Golfstroms, Bremen, 1868, also deals with some
of the earlier references.

AmontTst those who have specially dealt with the botanical side
of the subject in recent years are Hemsley, Lindman, and Sernander.
The two last named were exclusively concerned with the drift of
the Scandinavian beaches, and their results are given by Sernander
in his work on the distribution-biology " of the Scandinavian
plant- world (Upsala, 1901). The first named reopened the whole
inquiry in his botanical contribution to the reports of the Challenger
Expedition, and in its pages largely guided the investigations of
later students like myself. But it would be unjust if one did not
refer to one of the old veterans who did so much to establish clear
conceptions concerning the nature and source of the foreign seed-
drift on our European coasts. In the foremost place comes Sir
Hans Sloane, who from experience derived from a sojourn of fifteen
months in Jamaica, 1688-9, was enabled to identify the names and
determine the origin of several of the strange seeds and fruits stranded
on the Irish and Scottish coasts and on the islands to the north,
his results being given in the Philosophical Transactions for 1695-7,
and in the account of the natural history of Jamaica, which occupies
most of his work on the West Indies. He naturally came to the
conclusion that these West Indian seeds had been brought by the
" Currents and Seas."

The early Scandinavian References. — It is interesting to
notice how in Scandinavia the crude surmises of the early writers
on the natural history of these regions gave place to the more accurate
determinations of the Linnean school of botanists. In the first
place stands Peter Claussen (Peder Clausson), the Norse writer, who
in his Description of Norway published in 1632, nine years after his
death, refers to the seeds of Entada scandens as " stones floated
on to the coast," both in Scandinavia and the Faroe Islands.
Claussen was merely reiterating the old Norse belief, which found
expression in such names as adder-stones," " eagle-stones," etc.,
that were applied to these drift seeds, a matter mentioned again in
a later page of this chapter. One of the earliest to perceive their
real nature was Olaus Worm, a Danish naturalist of the seventeenth
century, whose Epistolce are quoted by Gumprecht (p. 420). He
determined them to be leguminous, and referred them to two genera
of Indian beans. Amongst the first to recognise their place of origin
was Provost Lucas Jacobsen Debes, who in his Faeroa Reserata or
Faeroe Revealed, published at Copenhagen in 1673, stated his opinion
that the seeds came from the West Indies and were " brought hither
by the Stream." This early reference to the Gulf Stream striking
the north-west shores of Europe may merit the attention of the
geographical student.

But the popular notion as to their inorganic origin long survived,
and it succumbed only to give place to another erroneous idea that
they were the product of marine plant-like organisms, such as the
" aleyonarian sea-shrubs." Thus Pontoppidan, the famous Bishop
of Bergen, in his book on the Natural History of Norway, which was
issued at Copenhagen in 1751, gave the name of Faba marina, or Sea

22 PLANTS, SEEDS, AND CURRENTS

Bean to the stranded seeds of Entada scandens, regarding them as the
products of the " sea-trees " (sea-fans, etc.). These " sea-shrubs "
may attain a considerable size on our coasts. Sloane, who in his return
voyage from the West Indies touched at the Scilly Islands, writes (II.,
347) that on these rocks grows the Frutex marinus, flabelliformis,''
a specimen seen by him having " such dimensions and beauty that
King Charles II. kept it many years, even to his death, for the orna-
ment of his closet."

Sea Bean and Sea Nut are names still applied, as I found, in various
parts of the world to the seeds of Mucuna and Entada when picked
up either afloat in the sea or stranded on the beach; and one hears
at times some singular opinions as to their origin. On one occasion
I had a difficulty in persuading a gentleman, who wore a seed of
Mucuna urens as a charm on his gold chain, that it was not some
spontaneous production of the waves. The appellation of Gulf
Nut, used at times by those who gather these seeds on European
beaches, would be more appropriate.

Gunnerus, Bishop of Drontheim, and Strom, the Norwegian
naturalist, first supplied the materials for the identification of the
tropical elements of Scandinavian beach-drift to the Linnean botan-
ists; and, as Sernander points out (p. 116), it is through the work
of Tonning, a pupil of Linnaeus, that their observations are usually
known to the world (Amosn. Acad., VII). Although seemingly
not acquainted with Sloane's writings, Gunnerus formed independ-
ently the same conclusions respecting the origin of the foreign seeds
and fruits in the drift. His observations were published in the
memoirs of the Drontheim Society (Copenhagen, 1765); and the
results together with the botanical identifications of the plartts were
incorporated by Tonning in his paper. Strom refers to the foreign
drift in his description of the bailiwick of Sondmore, published in
1766, a work quoted by Gumprecht (p. 420). I do not gather that
the matter attracted the special attention of Linnaeus beyond the
fact that in the following volume of the Amcenitates he cites, in
illustration of the ocean's part in seed-distribution, the seeds and
fruits washed up on the coasts of Norway, as specified by Tonning.

The Early Scottish References. — In their quaint descriptions
of the Hebrides, the Orkneys, and the Shetland Islands, the old
authors often give prominence to the foreign drift seeds stranded on
their shores. Under the curious name of Molucca Beans " we find
their virtues described, both real and imaginary. Master James
Wallace, minister of Kirkwall, in A Description of the Isles of Orkney
published in 1693, and his son, Dr. James Wallace, F.R.S., in the
edition of his father's book, which was issued with additions in 1700,
were among the first to direct the attention of British naturalists
to this matter. In 1703 Mr. Martin Martin, a native of the Hebrides,
gave to the world an account of these islands in A Description of
the Western Islands of Scotland, where he dwells especially on the
medicinal virtues of the " Molocca Beans " and on their efficacy
as charms against the " evil eye." Mr. Thomas Pennant in A
Voyage to the Hebrides in 1772 places these nuts commonly called
Molucca Beans " amongst the amulets employed by the islanders.

WEST INDIAN DRIFT ON EUROPEAN SHORES 23

In the foregoing pages I have paid the debt due to many of my
earher predecessors in this Hne of research, and must refer the reader
for a fuller description of many of the works named to the biblio-
graphy at the close of this chapter.

The Original Popular Names in Europe of the West Indian
Drift Seeds and the Superstitions connected with them. —
Reference has already been made to Molucca Beans " as the name
of these seeds in the Hebrides and Orkney groups in the latter part
of the seventeenth century. Its origin is obscure. The younger
Wallace (1700) particularly observes that he did not know the reason
of this name as used by the Orkney islanders; but Sloane in his
Natural History of Jamaica (II., 41), published a few years after,
states that the seeds are called Molucca Beans by the Inhabitants
of Scotland, they supposing them to have come from those islands
by an imaginary North East Passage." Several writers quote in
this connection the Scotia Illustrata of Sir Robert Sibbald, Geographer
Royal to Charles II., a work issued in 1694 ; but he merely includes
Phaseoli Molucani in a catalogue of marine plants and other things
" qua3 in Mari proveniunt " (II., lib. 4, p. 55). The appellation is em-
ployed in dictionaries of the Scottish language in the interpretation of
the vernacular names applied to the foreign seeds of the beach-drift,
a matter alluded to later in this chapter ; but no endeavour to throw
light on the origin of the epithet " Molucca " came under my notice.
It is, however, noteworthy that both Martin and Sibbald in the
works above quoted use the expression " Indian Nuts " or Nux
Indica to distinguish one or more of the Molucca Beans.

Gumprecht (p. 420) gives a number of Scandinavian vulgar names
of these drift seeds, as obtained from the older Norwegian writers,
names which indicate the prevalent superstitious beliefs connected
with their origin " Ormesteen " or Adder- stone, " Losningsteen " or
Solvent-stone, " Buesteen " or Bent-stone, are some of the old Norse
names cited. The first was probably applied to the pale-coloured
marble-like seeds of Guilandina bonducella, and the third to the seeds
of Erythrina on account of their form. The Solvent-stone, according
to Tonning, was the name of the large seed of Entada scandens,
doubtless in indication of some special virtue attributed to it by the
people.

It was around the Entada seeds that superstition often centred.
Debes, the historian of the Faroe Islands, displays some irritation
against Claussen who credited the Faroe islanders with the Norv/egian
belief that one of these seeds " doth bring forth another stone when
it is kept long." " It is very certain " (Debes goes on to explain)
" that these seeds are found here ; but the inhabitants have not that
superstitious opinion of them. Neither is it any stone, but a West
Indian bean, as hath been told me by a very knowing man." Debes
wrote his book about 1670. It was published in Copenhagen in
1673, and the English translation by J.S. (identified in the British
Museum catalogue as John Sterpin) was issued in London in 1676.
We learn from Debes and Claussen that both in the Faroe Islands
and in Norway the seeds of Entada scandens were named " Vette
Nyre." This is translated by Sterpin as " Fairies' Kidneys " ; but

24 PLANTS, SEEDS, AND CURRENTS

Gumprecht (p. 417) turns it into German in the shape of " Fette
Niere," of which " Fat Kidney " would be the EngUsh equivalent.
Both in colour and form these seeds might be compared with kidneys,
and Sterpin's rendering is the one adopted in the pages of Fogh, Vibe,
and Kohl, the name being regarded as the equivalent of the German
" Zauber-Nieren " (magic or fairy kidneys), which becomes intelligible
in the light of the employment of these drift seeds as charms.

It is, therefore, not a matter for surprise that these strange seeds
when picked up on the beaches of north-western Europe have been
used as charms. We have already remarked on their employment
for this purpose. Pennant, as we have seen, in his book on the
Hebrides classifies them among the amulets. But it is to the earlier
work of Martin on the same islands that we are indebted for particu-
lars in this respect. Of the seeds stranded on the island of Harris
he writes : " There is a variety of nuts, called Molluka Beans, some
of which are used as Amulets against Witchcraft or an Evil Eye,
particularly the White one, and upon this account they are Wore
about Childrens Necks, and if any Evil is intended to them, they say
the Nut changes into a black colour. That they did change colour
I found true by my own observation, but cannot be positive as to
the Cause of it." (This white nut is evidently the seed of Guilandina
honducella.) Martin goes on to say that it is called " Virgin Marie's
Nut," and he gives an instance of its effect in removing the spell of
witchcraft from cows which gave blood instead of milk.

Whilst noticing the employment of these drift seeds as charms one
may direct attention to an interesting observation made by Hemsley
in the Annals of Botany for 1892. He refers to a peculiar virtue
which not so long ago the people of the Hebrides ascribed to the
black seeds of Ipomosa tuberosa, one of the most remarkable of the
West Indian seeds thrown up on those islands. He is quoting from
an extract of the journal of Colonel H. W. Fielden, which was sent
with one of these seeds to Kew about 1891. The specimen was
given to this officer by a woman of North Uist, in whose family it
had been kept for a couple of generations. Known amongst the
Roman Catholic inhabitants of Long Island under a Gaelic name
signifying " Mary's Bean," it was believed to ensure easy delivery
when clenched in the hand of a woman in childbirth.

Doubtless the belief in the protective powers of the West Indian
seeds thrown up on their coasts yet lingers with the fisherfolk of
the Scottish islands ; and in the Shetlands, as I have been told, the
wives of the fishermen still make ornaments of them. But these
islanders appreciate these gifts from the waves in another way.
Martin tells us of the medicinal uses to which the Hebrideans and
the people of Mull put the Molucca Beans or Indian Nuts. We are
informed that for the cure of dysentery and similar complaints the
powdered kernels of the black " Molocca " Bean (Entada scandens)
and of the " white Indian Nut " {Guilandina honducella) when drunk
m boiled milk are " by daily experience found to be very effectual."
One would have scarcely expected the seeds of the last named to
be very efficacious ; but Sloane states (IL, 41) that numerous virtues
were ascribed to the seeds of Guilandina bondu£ella in the West

WEST INDIAN DRIFT ON EUROPEAN SHORES 25

Indies, and that their medicinal value was greatly esteemed by
the Turks.

Almost everywhere on the European shores of the Atlantic the
stranded seeds of Entada scandens seem to have been used as snuff-
boxes; and in some places they served as tinder-boxes or match-
boxes. Many of the old authors (Sibbald, Debes, the two Wallaces,
Sloane, etc.) allude to the snuff-boxes improvised from these seeds
on the north-west coasts of Scotland, the Orkney Islands, and the
Faroe Islands ; and it is evident from the condition of seeds sent to
me from the Shetland Islands that the islanders utilised them for
one or other of these purposes. In Scandinavia they were also thus
employed. Thus De Capell Brooke, in his account of his travels
in these regions in 1820, refers to the conversion by the Sea Finns of
the seeds of Entada scandens into snuff-boxes.

According to Martin the black " Molucca Bean was specially
named " Crospunk " in the Hebrides. In Warrack's A Scots Dialect
Dictionary (1911) this name is applied to " the Molucca beans drifted
to the shores of some of the western islands " ; but no etymology
is given. This information was apparently derived from Jamieson's
Etymological Dictionary of the Scottish Language, in which Martin
is quoted as the authority. The suggestion in Jamieson's work
(edit. 1879) that the word " would seem literally to mean in Gaelic
the point of the cross " can scarcely be sustained, since a more probable
origin presents itself in the old Scottish term spunk-box for match-
box or tinder-box. Evidently the large seeds of E^itada scandens
are here implied. We have already noted their use as snuff-boxes,
match-boxes, etc., and the writer has himself found them in use as
match-boxes at the present day in several of the tropical homes of
the plant. Originally the spunk-box was the Hebridean's tinder-box
and afterwards his match-box; and when the West Indian drift
seed served the same purpose he gave it the same name. The prefix
need present no difficulty, since in Gaelic cro is a prefix possessing
among other meanings those of witchcraft and sorcery. (See
Dictionarium Scoio-Celticum, sl Dictionary of the Gaelic Language :
Edinburgh, 1828.) On this view crospunk might signify " the
magician's tinder-box." We have already seen that in the Faroe
Islands nearly two and a half centuries ago the same West Indian
drift seed was known as Fairy's Kidney.

Before discussing the West Indian seed-drift of European beaches
according to the localities in which it has been found, I will give the
list of the seeds and fruits that are most characteristic of it(pp. 26, 27).

It is doubtful whether the seeds of any but the leguminous
plants in the following list would retain their germinative capacity,
which, it may be observed, has been established in the cases of the
Entada, Guilandina, and Mucuna seeds. It would be hopeless to
attempt to raise plants from the Manicaria specimens, and the
result would be uncertain in the case of Sacoglottis and Sapindus.
The prospects of success would be greater with Ipomoea tuberosa.
The seeds of Crescentia gourds would be lifeless, and the fruits of
Astrocaryum would be empty. Dioclea seeds would be sound, and
Erythrina seeds might preserve their vitality.

26 PLANTS, SEEDS, AND CURRENTS

List of the Characteristic West Indian Drift Seeds and Fruits

France
(north
coast)

England
(southern
and south-
western
coast)

Wales
(south
coast)

Ireland
(west
coast)

(west
coast) and
Hebrides

Orkneys

I.

Sacoglottis
amazonica
(Humiriaceae)

+

II.

Sapindus
saponaria
(Sapindacese)

III.

GUILANDINA
BONDUCELLA

(Leoruminosae)

+

+

+

IV.

Entada
scandens
(Leguminosae)

+

+

+

+

+

+

V.

Mttcuna urens
(Leguminosae)

+

+

VI.

MucuNA near
urens

(Leguminosae)

+

+

VII.

DiOCLEA

reflexa
(Leguminosae)

+

VIII.

Erythrina
(Leguminosae)

+

IX.

Ipomcea
tuberosa
(Convolvulaceae)

+

X.

Gourds

{Crescentia ?
Bignoniaceae)

XI.

Manicaria
saccifera
(Palmaceae)

XII.

ASTROCARYUM

(Palmaceae)

1 The details for all the plants in this list

WEST INDIAN DRIFT ON EUROPEAN SHORES 27

FOUND ON THE BkACHBS OP WESTERN EUROPB AND OF THE AZORES.'

Shbt-

LANDS

Faroes

Norway,

SWKDBN,
DENMARK,

and
Baltic
Coasts

Azores

Remarks

+

+

+

+

+

+

+

+

4-

For reasons given in the separate
treatment of the genus it is probable
that some of these records should be
referred to the species below.

+

-f

+

Evidently the type of Mucuna seed
most frequently gathered on the
beaches of Europe. (See above re-
mark.)

+

Probably a few of the Mucuna
records were referred to this species.

+ ?

It is surmised that the Norse name
of Buesteen (G. Bogensteine; E.
Bentstone) was applied to a species
of Erythrina.

+ ?

It may be that the large Convol-
vulaceous seed found by Lindman on
the coast of Norway in 1880 belongs
to this species.

+ ?

In the special treatment of Gourds
found on European beaches it is
shown that they are more likely to
belong to the genus Crescentta than
to that of LcLQtncLTici.

+

will be found by consulting the Index.

28 PLANTS, SEEDS, AND CURRENTS

There have also been recorded from European beaches such
tropical fruits as those of Anacardium occidentale (Cashew-nut),
Arachis hypogcea (Pea-nut), Caryocar nuciferum (Butter-nut of
Guiana), Cassia fistula, Cocos nucifcra, Garcinia mangostana (Mango-
steen), etc., all of which, whether introduced or indigenous, are now
growing in the New World. The extreme probability of their
having been derived from ships in the vicinity is pointed out in
later pages.

The South- West of England. — Respecting the occurrence of
West Indian seeds on the beaches of the south-west of England, the
following remarks may be made. Mr. Hamilton Davey, the author
of The Flora of Cornwall, tells me that he has often found on the
Cornish coast between St. Ives and Newquay large seeds which he
took to be those of Entada scandens, and that he had them sawn through
for the benefit of his students. It is well known that Gulf Stream
drift is not infrequently beached on the north coast of Cornwall.
The Great W^estern Railway Company, in advertising the climatic
attractions which the " Cornish Riviera " derives from the Gulf
Stream, informs the public that " many have been the instances of
West Indian drift cast upon the shores of St. Ives Bay."

I noticed a seed of Mucuna urens from Cornwall in the Kew
Museum. There is also exhibited there a fruit of Sacoglottis amazonica
gathered on the South Devonshire coast by Mrs. Hubbard in Novem-
ber 1887. The find of the Sacoglottis fruit by Mrs. Hubbard had an
important result. The fruit was unknown at Kew, and the requisite
inquiry instituted by Sir D. Morris, Mr. Hillier, and others led to
the identification of this and other fruits of the same plant from the
drift of West Indian beaches, a matter dealt with in the discussion
on Sacoglottis amazonica. Sir D. Morris, when referring to these
drift fruits in Nature for November 21, 1895, gives Mrs. Hubbard's
Devonshire locality as Bigborough Bay. Evidently Bigbury Bay,
a few miles west of Salcombe, is here meant.

On April 28, 1909, I found on the beach at Sewer Mill Cove, near
Salcombe, South Devon, two seeds lying within a few paces of each
other, both in a sound condition, one of Guilandina honducella and
the other of the Mucuna species near M. urens. On January 18,
and April 2, 1912, I came upon solitary seeds of Entada scandens
at Moor Sands and at Sewer Mill Cove, beaches lying east and west
of Salcombe, one of them with the base of a Balanus shell still
attached. Though in both cases the seeds appeared sound, they
possessed rattling broken kernels, and neither of them could have
been germinable. The drift is sometimes carried far up the
English Channel. Thus a Mucuna seed has been picked up at
Portsmouth (Hemsley in Chall. Bot., IV., 291), and in the Kew
Museum there is a seed of the same genus, labelled " near urens,^^
which was found at St. Helens in the Isle of Wight. A seed of
Entada scandens, now in the Kew Museum, was given to me by Miss
M. Moseley, who found it in 1897 on the beach at Vimereux near
Boulogne.

It is noteworthy that my discovery on the south coast of Devon
of seeds of Entada scandens in the middle of January and early in

WEST INDIAN DRIFT ON EUROPEAN SHORES 29

April 1912, corresponds with the driftinjr into these latitudes from
the southern waters of the North Atlantic of large quantities of
Physalia (Portuguese men-of-war) and other pelagic organisms.
Dr. Orton in Nature^ February 27, 1913, observes that during March
and early April 1912, numbers of Physalia were cast on our shores
at various points between Cardigan Bay and Seaford in Sussex,
and that together with Velellce others were washed up at the same
time on the coasts of France. (With respect to the Velellce a French
naturalist is cited.) At the end of March 1912 I noticed " Portu-
guese men-of-war " stranded in quantities on the beaches of South
Devon between Start Point and Bolt Tail. On showing some of
them to persons in the habit of crossing Salcombe Harbour daily,
I learned that these creatures had been recently observed sailing
up the harbour in small fleets. Their condition on the beaches
indicated that whilst some had been beached only for a day or two,
others had been lying there for a week or more. Dr. Orton regards
this extensive incursion into our latitudes of the surface organisms
of southern waters as the result of the almost continuous high
southerly to south-westerly winds in the south-eastern part of the
North Atlantic in the early part of the year.

There was a similar invasion of our seas by southern pelagic organ-
isms in the early part of 1913. Commander Campbell Hepworth,
in a paper in the Geographical Journal (November and December
1914), quotes from Dr. Orton's letter in Nature, and adds on the
authority of Dr. Allen that Physalia occurred on the south coast of
England in February, March, and April 1913. No West Indian
drift seeds were noticed by me on the south coast of Devon in this
connection; but early in January of that year after a long period
of strong south-westerly winds I found an abundance of the horny
skeletons of Velellce on a beach near Salcombe. During the first
two or three days of January 1916 an enormous number of Velellce
were piled up on the beaches of South Devon, east and west of Sal-
combe, in the living state. The spectacle was unique. Commander
Hepworth refers to the occasional presence " especially off the west
coast of Ireland, but seldom off Devon and Cornwall " of lanthina
(Violet Sea-snail) and Velella. However, lanthina often came under
my notice as a boy on the Cornish beaches. The association in this
paper on the Gulf Stream of the indications of the pelagic organism
with those of the thermometer and hydrometer endows it with
special value for the student of dispersal by currents.

On the beaches of South Devon one occasionally finds Pea-nuts
(Arachis hypogcea), half-eaten ears of Maize, Coco-nuts, etc., evidently
thrown over from ships approaching the English Channel, besides
other fruits and seeds, the origin of which is uncertain. Thus on
May 16, 1911, two large Sapotaceous seeds, 2 J inches in length,
were picked up by me on Rickham and Moor Sands beaches near
Salcombe. Dr. Rendle tells me that a specimen sent to him pre-
sumably belonged to Lucuma, the species being doubtful. From
a comparison with seeds in my collection of Lucuma mammosa, the
familiar Mammee-Sapota of the West Indies, it is evident that the
drift seeds do not belong to that species, though similar in size.

30 PLANTS, SEEDS, AND CURRENTS

Then again on November 17, 1914, I found washed up on Rickham
beach a nearly entire fruit of Passiflora and a portion of a second
fruit. The seeds of both were dead. On January 11, 1916, I picked
up on the same beach another entire fruit of the same species of
Passiflora, containing sound seeds from which I am now raising
healthy seedlings. It was lying amongst the dead Velellce that
had been thrown up in such quantities a few days before, and
doubtless arrived with them. The fruits reminded me of the
Water Lemon of Jamaica (P. laurifolia) ; but since Passifloras
are cultivated in England, and some grow almost wild in Ireland
and in the south-west of England, we can scarcely look to the
West Indies for the source of these drift fruits. Further details
will be found given in connection with Passiflora in the Turks
Islands.

The South Coast of Wales. — West Indian drift seeds and fruits
are sometimes carried into the Bristol Channel and stranded on the
Welsh coasts. Several years ago Dr. A. Lloydd-Jones sent to Kew
a seed of Entada scandens, " said to be exactly like one picked up
in Swansea Bay" {Kew Bulletin, 1893, p. 114). On these coasts,
as on the shores of the English Channel, the buoyant portions of
edible tropical fruits thrown over from passing ships must often
be cast up on the beaches, and allusion has above been made to this
point with respect to the south coast of Devon. Thus in the Kew
Museum there is a perfect specimen of a Mango-stone {Mangifera
indica) from the coast of South Wales, which was probably thus
derived. As is shown in a later page, empty Mango-stones are of
common occurrence on West Indian beaches and elsewhere. There
is also in the drift collection of the Kew Museum a fruit from South
Wales which is labelled Caryocar nuciferum, the *' butter-nut " of
British Guiana, sometimes imported into Great Britain.

The West Coast of Ireland. — It is shown in the next chapter
that much of the bottle-drift which reaches the shores of the United
Kingdom from the seas of the West Indies, Florida, and the South-
eastern United States is stranded on the west side of Ireland. This
fact would lead us to expect that the Irish coasts would receive the
bulk of the West Indian seed-drift thrown up on our shores. But
I gather that though often found it has rarely been recorded. The
principal fact usually cited is that given by Sir Hans Sloane in his
book on the West Indies (II., 41) and in his paper in the Philosophical
Transactions (Vol. XIX.), which were written more than two centuries
ago. He there alludes to seeds of the " ash-coloured Nickar " and of
the " Cocoon " found on these coasts. There can be no doubt that the
seeds of Guilandina honducella and Entada scandens are here indicated.
From a drawing made of a plant raised from a seed picked up on
the west coast of Ireland Robert Brown determined the species to
be Guilandina bonduc (Hemsley in Chall. BoL, IV., 277). Since,
however, the seeds of this species are not as a rule buoyant in the
West Indies and are not a frequent constituent of West Indian
beach-drift, it is more probable that the seeds in question belonged
to the allied species, G. honducella, the seeds of which have been
found in almost every European locality where West Indian drift

WEST INDIAN DRIFT ON EUROPEAN SHORES 31

has been observed. For further details on this point Note 9 of the
Appendix should be consulted.

Through the courtesy of Mr. Lloyd Praeger I have received whilst
preparing this work some more particulars about West Indian seeds
on the western sea-borders of Ireland. The following extract is
from a letter of April 29, 1915, written to him by Miss M. C. Knowles
of the National Museum, Dublin : " On p. 133, Irish Naturalist
for 1897, I see Mucuna urens was picked up on the shores of Kilkee
(Co. Clare). Mr. Tomlinson sent me Entada scandens that he had
found on the north coast a short time ago, but he did not give me
the locality. I have found it at White Park Bay (Co. Antrim) on
several occasions."

On September 2, 1915, Miss Knowles wrote to tell me of two
seeds, Entada scandens and Mucuna sp., just brought to her, which
were found by the Rev. Br. S. O'Connell in a cave at Kilkee. They
were sent to me for inspection by the Rev. Br. M. A. Hoban. Both
of them appeared to be sound and germinable. The Mucuna seed
came nearest to those of M. urens. I may add that with the object
of directing interest to this matter I sent in May 1915 to the National
Museum, Dublin, a collection of West Indian drift seeds most likely
to be found on the Irish coasts.

The West Coast of Scotland and the Hebrides. — As already
observed. Sir Robert Sibbald in his Scotia Illustrata (II., lib. 4, p. 55,
1694) includes, without commenting on their origin, Phaseoli Molucani
and Nux Indica in a catalogue of marine plants and other things
" quas in Mari proveniunt." The use of the name Molucca Beans has
been before explained. The Indian Nut, " of which snuff-boxes
are made," is evidently Entada scandens, and is thus regarded by
Sloane, who identifies it in his paper in the Philosophical Transactions
with the Cocoon, which is its native name in Jamaica. Amongst
the West Indian seed-drift stranded on the north-west coasts of
Scotland and on the Hebrides, and described by Sloane in his Voyage
to Jamaica, etc. (II., 41, 186), are represented Guilandina bonducella,
Sacoglottis amazonica, and Manicaria saccifera. The first named
can be at once recognised from his account. As regards the other
two species, the identification of the Manicaria fruits was made by
Plukenet ; whilst the description of the Sacoglottis fruits, as quoted
by me under that head, leaves no room for doubt as to their identity.

We have before referred to the account which Martin gives in
his Description of the Western Islands of Scotland (1703) of the
medicinal uses to which the Hebrideans and the people of Mull put
the Molucca Beans and Indian Nuts washed up on their shores,
and we have dwelt also on his account of the superstitions attached
to them. Amongst the seeds he mentions we can recognise those
of Entada scandens and Guilandina bonducella. He adds (p. 283)
that the Steward of St. Kilda told him that they had found Molucca
Beans in a nest of the Solan Goose, it being the habit of these birds
to carry to their nests many things they find afloat in the sea. This
is interesting in connection with the discovery by Sir William Milner
of large West Indian seeds in the crops of nestling petrels at St.
Kilda, a matter which drew the attention of Darwin, and is treated

32 PLANTS, SEEDS, AND CURRENTS

in Note 59 of my work on Plant Dispersal. Mr. Charles Dixon in
Ibis (1885) refers to Sir W. Milner's observation in the case of the
Fulmar Petrel and speaks of them as Brazilian seeds brought by the
Gulf Stream, adding that he himself found a specimen in the crop
of one of these birds in the same locality. Sir W. Milner, it appears,
procured several of these seeds from the crops of the birds, and
Mr, Dixon says that the natives of the island find them at times*
The reference by Darwin is made in letters to Hooker in 1859 (Life
and Letters, 1888, II., 147-8). He remarks on the curious fact of

petrels at St. Kilda apparently being fed by seeds raised in the
West Indies." Unfortunately the seeds were never identified, and
more than forty years afterwards, when Mr. Hemsley applied to Sir
Joseph Hooker for particulars, too long an interval has elapsed for
the determination of this point. The West Indian drift seeds carried
to our islands that would be most likely to be swallowed by sea-birds
would be those of Guilandina bonducella. When in the Keeling
Islands I was informed by residents that the seeds of this plant,
which grows on the islands, are sometimes found in the stomachs
of sea-birds, such a frigate-birds and boobies.

Pennant in his Voyage to the Hebrides in (I., 266) refers to

" the nuts commonly called Molucca Beans which are frequently
found on the western shores of the Hebrides." He is one of the
first to employ the Linnean designations in naming the seeds stranded
on the Western Islands of Scotland, and his list comprises Dolichos
(Mucuna) urens, Guilandina bonduc, G. bonducella, and Mimosa
(Entada) scandens, all, as was long before pointed out by Sloane,
natives of Jamaica. He adds C. Bauhin's description, derived
from Clusius, of a fifth kind, which is evidently the composite seed
of Ipomoea tuberosa, and special reference to it in this connection
will be made when dealing with that species. There is in the Kew
Museum another drift seed of the same species of Ipomoea from
the Hebrides, which was obtained by Colonel Fielden about 1891.

A well-known Genevese naturalist, Necker de Saussure, made a
long sojourn in the Hebrides between 1806 and 1808. Speaking
of the " American " seeds, Dolichos (Mucuna) urens and Mimosa
(Entada) scandens, which had been thrown up by the waves, he says
that when traversing South Uist he observed them in every cottage
(Voyage en ilcosse et aux lies Hebrides, 1821, III., 22). There are
doubtless numerous references in modern works to the West Indian
seeds transported to these islands. For instance, Mr. C. V. Peel
in his Wild Sport in the Outer Hebrides, 1901, mentions the seeds
of the two species just named as occurring with much other Atlantic
drift on the west coast of North Uist.

The Orkney Islands. — These islands are of special interest in
the story of this investigation, since the stranded " Molucca Beans "
(as they were called), which were figured by the two Wallaces, the
early historians of the group, were in most cases identified by Sloane
with seeds familiar to him in Jamaica (Phil. Trans. 1695-7). Stand-
ing thus on firm ground when he surmised that the seeds had been
brought by the sea from the West Indies, Sloane forestalled by
quite two generations the Norwegian observers of the middle of

WEST INDIAN DRIFT ON EUROPEAN SHORES 33

the eighteenth century. Yet, as before remarked, even Sloane
must in this respect give way in point of priority by at least a
quarter of a century to Debes (1670) and his informant, the " very
knowing man," who regarded the strange seeds stranded on the
Faroe Islands as " brought hither by the Stream " from the West
Indies.

But to return to the Wallaces, I examined the three editions of
this early description of the Orkney Islands that are in the British
Museum library. The first, " A Description of the Isles of Orkney
by Master James Wallace, late minister of Kirkwall, published after
his Death by his Son " was issued at Edinburgh in 1693. It was
written about 1688 at the instigation of Sir Robert Sibbald, Geogra-
pher to Charles II. Under the head of substances cast up by the
sea he alludes (p. 14) to the frequent occurrence of " these pretty
Nuts (named Molluca Beans in the margin) of which they use to
make Snuff-Boxes. There are four sorts of them (he adds) the
figures of which are set down." In the plate under the name of
" Molocca Beans " are figured the seeds of Entada scandenSy a
species of Mucuna, probably M. urens, a species of Erythrina, and
Ipomoea tuber os a.

Though written without any mention of his father's book. An
Account of the Islands of Orkney by James Wallace, M.D., F.R.S.
(London, 1700), is evidently an enlarged edition of the previous
work. With access to Sloane' s paper in the Philosophical Transactions
(1695-7), which his father could not have had, the author thus
writes (p. 36) : " After storms of Westerly Wind, amongst the
Sea- Weed they find commonly in places exposed to the Western
Ocean these Phaseoli that, I know not for what reason, go under
the name of Molucca Beans. The ingenious Doctor Sloan in the
Philosophical Transactions, Number 222, gives a very satisfactory
account, how from the West Indies^ where they commonly grow,
they may be thrown in on Ireland, the Western parts of Scotland,
and Orkney. You have the figures of four different sorts of them."
However, in his plate there is a fifth figure of " another molucca bean "
which is certainly Guilandina bonducella. The drawing of the seed
of Entada scandens is here enlarged to natural size, and in the place
of his father's figure of a Mucuna seed there is a drawing of a Dioclea
seed. The other seed-figures, one of an Erythrina species and the
other of Ipomoea tuberosa, are unchanged.

The third edition, which is entitled " A Description of the Isles of
Orkney by the Rev. James Wallace, reprinted from the edition of
1693 and with additions by the Author's son in the edition of 1700,"
was edited by John Small and published at Edinburgh in 1883.
This work contains both the plates of the seed-drawings of the two
earlier editions. It may here be remarked that an additional reference
to the occurrence of the seeds of Ipomoea tuberosa on the Orkney
beaches at the close of the seventeenth century is made by Petiver,
of which further mention will be made.

The next important reference to seeds of West Indian beach-drift
i on the coasts of these islands is to be found in " An Account of four
i sorts of strange beans, frequently cast on shoar on the Orkney Isles,

D

34 PLANTS, SEEDS, AND CURRENTS

with some conjectures about the way of their being brought thither
from Jamaica, where three sorts of them grow " by Sir Hans Sloane
(Phil. Trans. 1695-7). After referring to the mention of them by
Sibbald and the elder Wallace, he deals with them successively.
The first he identifies with the Jamaican Cocoon," the name given
in that island to the seed of Entada scandens, as known to botanists.
The second, he says, is the Jamaican " Horse-eye bean," which from
his description is evidently the seed of Mucuna urens, a seed that
bears the same popular name in our own time. The third, he says,
is the " ash-coloured Nickar " of Jamaica, called so, as he goes on
to state, from its being " very like a Nickar," such as boys play
with. I may add that *' knicker," " nicker," etc., were forms of
an old English and Scottish name for marbles. Botanists have no
hesitation in recognising here the seeds of Guilandina honducella. It
bears the same common name in the West Indies now. Of the source
of the fourth he states that " authors are silent " ; but although
he remarks that he " had never seen it grow," his reference to it
as described and figured by Clusius, the elder Wallace, and others,
undoubtedly points to its being the seed of Ipomoea tuberosa, as
determined in recent years by Mr. Hemsley, and to which further
allusion will be made. I have not come upon any recent
references to West Indian drift seeds in the Orkney Islands, but one
may note that Mr. Bullock, the naturalist, gathered seeds of Entada
scandens there about a century ago (A. de Capell Brooke in Travels
in Sweden, etc., in 1820, p. 317).

The Shetland Islands. — In connection with the occurrence of
West Indian seed-drift in this archipelago I put myself in communica-
tion with Mr. John Fox, then stationed in that group, and through
his kindness was able to inspect two seeds from the Shetland beaches,
one of Entada scandens, the other of Dioclea reflexa, both of them in
sound condition, which were courteously loaned by Mr. J. Tulloch
of Lerwick. Mr. Fox subsequently sent me two seeds of Entada
scandens, one of the species of Mucuna near M. urens, and a seed of
Ipomoea tuberosa, the last being the species above named as found
on the Orkney beaches, and it is one that is represented in my drift
collections from Jamaica and the southern extremity of the Bahamas.
All these seeds were picked up on the Shetland coasts, and Mr. Fox
tells me that the wives of the fishermen make ornaments of them.
In reply to a letter asking for further information, Mr. Tulloch kindly
furnished me with references to Shetland literature, but added that
he knew of no mention there of Gulf Stream drift. At his suggestion
I wrote to Mr. Peterson, postmaster of Foula, an island at the south-
west corner of the group ; but on doing so I learned that that island
is not suited for retaining drift, and that during a residence of over
fifty years Mr. Peterson had never seen any of the seeds described
to him by me.

The Faroe Islands. — The occurrence of these strange drift
seeds on the Faroe Islands formed a subject of remark for Peter
Claussen in his Description of Norway, which was written at the close
of the sixteenth or the beginning of the seventeenth century; but,
as previously stated, he had no idea of their true nature. Debes,

WEST INDIAN DRIFT ON EUROPEAN SHORES 85

who wrote the preface of his book on these islands in 1670, has been
already mentioned in connection with the drift seeds. It was,
however, with those of Entada scandens as found on the Faroe
beaches that he was especially concerned, and from his description
of them there can be no doubt as to their specific identity.

In 1817 H. C. Lyngbye, a Danish algologist, visited the Faroes,
and in his Tentamen Hydrophytologice Danicce of 1819 he remarks
(p. 60) that he picked up on the shores seeds of Mimosa scandentis
(Entada scandens), Dolichos urentis (Mucuna urens), and Guilandina
honducella. In recent years Ostenfeld and Borgesen have again
directed attention to the West Indian seeds and fruits washed up
on these islands, and they mention those of Cocos, Guilandina, and
Entada scandens as coming under their notice {Botany of the Faeroes,
pp. 116, 812 : Copenhagen, 1901-8).

Iceland and Greenland. — Seeds and fruits and drift-wood
from the New World are stranded on the shores of Iceland and Green-
land, as we learn from the Danish navigator. Admiral von Lowenorn
(1786), and from Barrow (1817), Sartorius von Waltershausen (1847),
Irminger (1854), and others. In his Physical Geography (1873,
p. 206) Laughton quotes from the report of the United Coast Survey
for 1860, to the effect that drift from the West Indian islands is
stranded in very considerable quantities on the south coast of
Iceland, where, " on the beach under Snaefell, trees with their
roots, and scraps of bark, logs of mahogany, and seeds which grow
in Jamaica at the nearest, roll in the surf." We learn from Irminger
(Zeitsch. f. Allg. Erdk., III., 187-90, 1854) that " many kinds of
Mimosas (i. e. seeds) are to be found on the coasts of Norway, Faroes,
Iceland, and Greenland, and also drift-wood." Von Waltershausen
in his work on the physical geography of Iceland (p. 347) refers to,
without naming, the tropical seeds and fruits thrown up with much
drift-timber on the coasts. With respect to Greenland Laughton
(p. 249) quotes Irminger to the effect that " beans of Mexican growth
are often washed up on the Greenland shores " ; and Kohl observes
(p. 160) that in the southern Danish settlements of Greenland on
the shores of Davis Strait every one knows the seeds of Entada
scandens, which are often cast up by the waves.

The Scandinavian Coasts. — The West Indian drift thrown up
on the Norwegian coast has been several times mentioned in previous
pages. Claussen and Worm in the seventeenth century and many
others in the eighteenth century, such as Gunnerus, Pontoppidan,
Strom, Tonning, etc., interested themselves in the matter. In the
early part of the nineteenth century Wahlenberg, the Swedish
naturalist, in his Flora Lapponica (1812, p. 506) referred to the seeds
of Mimosa scandentis {Entada scandens) and Dolichos urentis {Mucuna
urens) as washed up on the north and north-west coasts of Norway.
A few years after, A. de Capell Brooke in the account in his Travels
through Sweden, Norway, and Finmark to the North Cape in 1820
(pp. 295, 317, 318) alluded to the drift from the New World cast up
on the Norwegian coasts. On the Tromsoe and Rost coasts much
timber was found, including baulks of Honduras mahogany. Seeds
of Entada scandens are (he says) thrown up after great storms.

36 PLANTS, SEEDS, AND CURRENTS

Mr. Bullock, the naturalist, who had himself picked them up on the
Orkneys, identified the seeds.

In recent times we have Lindman and Sernander. The last
named deals especially with the subject in his Den Skandinaviska
Vegetationens Spridningsbiologi (Upsala, 1901, p. 116, etc.); and the
results obtained by Lindman and his predecessors, including the
Linnean botanists, are there discussed under the name of " Gulf
Stream products." Lindman made a comprehensive study of the
subject in 1880. It appears that the coasts northward from Sond-
more to Lofoten and Tromsoe receive most of the West Indian seed-
drift. But it reaches as far north as the vicinity of the North Cape,
and may even, as Robert has shown, double that promontory and
enter the White Sea. To the south it extends to the Swedish and
Danish coasts, and it is found on the shores of the Baltic Sea. The
seeds of most frequent occurrence are those of Entada scandens,
Guilandina bonducella, and Mucuna urens. In the first two cases
Lindman procured the germination of the seeds. Those of Entada
scandens have even been found in a subfossil condition in the peat-
bogs of Tjorn on the south-west coast of Sweden, having been
originally stranded in post-glacial times on a beach in that locality.

A word may be said here on the doubling of the North Cape by
West Indian seed-drift. That the seeds reach the extreme north
was long ago mentioned by Wahlenberg in the work quoted above,
^vhere he refers to them as washed up on the Finmark coast. Robert,
the French naturalist, who was in this region in 1835-6, states that
his companions found the seed of Mimosa (Entada) scandens on the
island of Mageroe, on which the North Cape lies. Lottin, he says,
picked up a seed of the same plant near the same promontory in
" Laponie " (Lapland), which would indicate a locality to the east
of the cape. Robert himself found the same seed on the shores of
the White Sea. Gumprecht, Fogh, Vibe, and others allude to these
interesting discoveries, the references to which are given at the close
of the chapter.

Amongst the stranded drift named in Sernander' s list are the fruits
of Anacardium occidentale, Cassia fistula, Cocos nucifera, Garcinia
mangostana (Mangosteen), Lagenaria vulgaris, etc. The Mangosteen
fruit was found by Lindman in 1879 cast up on one of the Lofoten
Islands, and was doubtless thrown over from a ship in the vicinity.
The two first named have not been found since the time of Gunnerus
and Strom in the middle of the eighteenth century ; and, as indicated
in later pages, their West Indian origin as components of Scandina-
vian beach-drift is improbable. Gourds and calabashes, sometimes
" worked," have been known to be stranded from time to time on
the coasts of Norway ever since the days of Gunnerus and Strom.
In the discussion of Crescentia it is stated that there are grounds for
the belief that some of these gourds of Norwegian beach-drift belong
to this genus. Crescentia gourds are in common use in the West
Indies, and form a characteristic feature of the drift on West Indian
beaches, the tree (C. cujete) being a native of that region. Lagenaria
gourds most probably reached the coasts of Norway from passing
vessels. Coco-nuts have been picked up on Norwegian beaches

WEST INDIAN DRIFT ON EUROPEAN SHORES 37

since the middle of the eighteenth century. They were mentioned
by Strom, Tonning, and Linna;us; and Sernander observes that
they are generally more or less injured. When at Trinidad some
years ago the present writer was informed by Dr. Fredholm that in
1885 he found three coco-nuts within a space of a hundred yards
on a beach of one of the Lofoten Islands, evidently derived from a
wrecked or a passing ship.

There must be numerous references in Danish literature to West
Indian seed-drift on the western coasts of Denmark. In Petermann's
Mittheilungen for 1877 (XXIII., 316) mention is made of an interesting
note by Prof. Erslev on the occurrence there of seeds of Entada
scandens and other tropical products which have been brought by
marine currents to the shores of Jutland (see the list of works quoted
at the end of the chapter).

The Azores. — The occurrence of West Indian seeds on the beaches
of the Azores has long been known. Darwin, who was especially
interested in the subject, obtained a number of seeds of Entada
scandens and Mucuna urens from these islands and sent them to
Hooker at Kew, who referred to the matter in his lecture on " Insular
Floras " delivered before the British Association in 1866 (reprint of
1896, pp. 15, 28 ; see also Hemsley's Chall. BoL, IV., 291). Speaking
of the Azores, Hooker remarked that " the large Bean-like seeds of
Entada, a West Indian climber, are thrown up abundantly on the
islands by the Gulf Stream, but never grow into plants, if indeed they
ever germinate on their shores." These seeds were sown at Kew,
and many germinated and grew to be fine plants, showing that
their immersion during a voyage of nearly 3000 miles had not affected
their vitality." (The Mucuna seeds are mentioned by Hemsley
as above quoted.)

During my sojourns on the Azores, especially on the north coasts
of San Miguel and at the western end of Pico, I paid much attention
to this point and obtained the following results. The drift seeds
are familiar to the people of the coast towns and villages, and are
as often picked up whilst floating off the shores by the fishermen
as they are gathered by the children on the scanty beaches. When
the purpose of my visit became known in any coast town or village
I was usually supplied with several specimens of Entada scandens
and of the two species of Mucuna (M. urens and an allied species)
represented in European beach-drift. Other drift seeds and fruits
are often overlooked or disregarded. Amongst them would be
the seeds of Guilandina honducella. On my displaying a specimen
to the people of Magdalena at the west end of Pico they soon brought
me a seed which had been found on the beach. The seeds were
nearly always sound.

I searched several beaches and picked up the following fruits
and seeds : two sound seeds of Sapindus saponaria, one at Magdalena
and the other at Porto Pym (Fayal) ; an empty fruit of Astrocaryum
near Magdalena; and a woody fruit, probably belonging to the
Juglandece, on San Miguel. The more conspicuous seeds of Entada
and Mucuna are soon found on the beaches by the inhabitants.
The seeds of Sapindus saponaria are particularly interesting, since,

88

PLANTS, SEEDS, AND CURRENTS

as far as I know, they have not been recorded from European
beaches. They are characteristic of West Indian beach-drift, and
have been known to germinate in the Bermudas after having been
brought there by the Gulf Stream.

The complete list of West Indian drift seeds and fruits known to
me as stranded on the Azores would be as follows : —

Entada scandens.
Mucuna urems
Mucuna near M. urens.
Guilandina bonducella
Sapindus saponaria.
Astrocaryum {Palmacece).

Note. — Of these the first four have been recorded from European
beaches. As in Europe, of the two kinds of Mucuna seeds that of
the true M. urens is least common, two-thirds of the seeds belonging
to the allied species and one-third to M. urens proper. The
fruit of Juglandeoe, being of doubtful origin, has not been included
in the list.

It is highly probable that these seeds reached the Azores from the
West Indies by the circuitous Gulf Stream route. The intervention
of the Sargasso Sea (20°-35° N. lat. and 40°-70° W. long.), where
there is little or no surface circulation, bars the direct route from the
West Indian region. As indicated by the bottle-drift data dealt
with in Note 12 of the Appendix, this seed-drift must have been at
first carried northward past Cape Hatteras towards the Nova
Scotian and Newfoundland coasts, which would involve a tedious
drifting passage of at least a year's duration.

Amongst the other constituents of Azorean beach-drift are lanthina
shells, Portuguese men-of-war (Physalia), a little dead Sargasso
weed, and pumice, the last often abundant, and as shown in Note 23 in
great part of local origin. The Sargasso question is treated in Note
29 of the Appendix ; but it may be here stated that living specimens
did not come under my notice on the Azores beaches, the dead
fragments, which are well incrusted with polyzoa, having been
derived, not directly from the Sargasso Sea to the south-west, but
by the circuitous route to the northward, past Cape Hatteras, which
is taken by the West Indian seed-drift.

The Canary Islands and Madeira. — The writer has come upon
no record of West Indian seeds stranded on these islands ; but from
the indications of bottle-drift discussed in Notes 27 and 28 of the
Appendix it is evident that seeds from the tropics of the New World
must be at times carried there. Although he spent several days
in examining the north coasts of Teneriffe, no seed-drift that he
could recognise as hailing from the New World came under his
notice. The shores of this island are as a rule not well suited for
catching drift; but there are localities, as in the cases of beaches
east of Orotava and on the east side of Point Hidalgo, where a con-
siderable amount of oceanic drift is cast up, as shown in the abundance
of Spirula shells, Portuguese men-of-war (Physalia), etc. It may

WEST INDIAN DRIFT ON EUROPEAN SHORES 39

be added here that Mr. Samler Brown in his Guide to Madeira
and the Canary Islands (8th edit., 1905) deals with many kindred
matters, but says nothing of the stranding of West Indian seeds.

The Risks of Premature Generalisations on the Dispersal
OF Seeds by the Great Oceanic Currents. — The discussion to
which this chapter has been devoted opens up a number of other
questions; and perhaps the one that will first present itself is that
connected with the path followed by the floating seed in its traverse
of the Atlantic. Without a fairly precise acquaintance with the
working of the currents in this direction it is hazardous to generalise
on the subject, and to indulge in a picturesque description of the
currents at work in distributing seeds.

The floating seed can tell its own story, but in a very imperfect
fashion. It can tell us nothing of its route and often nothing of
the duration of its ocean traverse; and although we should be
usually right in assuming that a tropical seed found on European
beaches came from the West Indies, it would not follow that it grew
in that region. There would be possibilities that it came originally
from the shores of the Spanish Main, or from the estuary of the
Amazon, or even from the mouth of the Niger, before it came within
the influence of the Gulf Stream in the Florida Sea. Nor could we
read its history in its specific name, since the great majority of
tropical seeds transported by the currents belong to littoral and
estuarine plants common to both the African and the American
sides of the tropical Atlantic, and under such circumstances any
discrimination as to source would be hazardous.

The need thus presents itself of looking elsewhere for evidence
to supply what is lacking in the testimony of the drifting seed, and
in our need we appeal in the following chapter to the evidence of
bottle-drift. This is all the more requisite since some of the state-
ments one reads concerning the agency of currents in dispersing seeds
require considerable qualifications and illustrate the necessity of
exact knowledge of the principles regulating the process. Thus in
the English form by Prof. Ainsworth Davis of Pouchet's VUnivers
(1906, p. 394) Dr. Karl Muller in Les Merveilles du Monde Vegetal
is thus quoted : " The great current which springs from the eastern
coast of South America has been known to bear a flotilla of thirteen
species of plants from Brazil and Guiana to the shores of Congo
in Africa. . . . Another grand oceanic current, traversing an immense
space of the torrid zone, constantly transports fruits from the shores
of India, which its waves tumultuously scatter on the rocks of
Brazil."

With regard to these currents it is not apparent what the writer
could have intended, since the great equatorial currents could only
carry materials from the Congo to Brazil, whilst there is no great
oceanic current that constantly transports Indian drift to Brazil.
It is true that a bottle has been known to reach the Brazilian shores
from off the coast of Natal, and that drift from the Indian Ocean
can at times find its way into the South Atlantic in a small branch
of the Agulhas Current that doubles the Cape, instead of being

40 PLANTS, SEEDS, AND CURRENTS

deflected eastward with the main stream; but it would certainly
be erroneous to speak of a grand oceanic current establishing constant
communication between India and Brazil. On a later page attention
is called to a serious blunder by which a bottle is made to reach
India from the tropical Atlantic instead of from the mouth of the
Red Sea, through a confusion between east and west longitude. In
this case fortunately the published record itself supplied the refuta-
tion; but this would not always be possible, especially in cases
where the supposed fact is quoted without the data.

Transport of Mahogany Logs to the Coasts of Greenland,
Iceland, and the North-West of Europe. — It is to be expected
that seed-drift from the tropics of the New World would be some-
times accompanied by trunks of trees from the same region. Gum-
precht (p. 430) mentions that Lowenorn, the Danish admiral, found
logs of mahogany in 1786 on the east coast of Greenland; and he
adds that trunks of the same tree are thrown up on the west coast
near the island of Disco. In the last case the wood was in such good
condition that the Danish governor had a table made of it. I have
already referred to Laughton's quotation from the report of the
United States Coast Survey for 1860 that mahogany logs are rolled
in on the coast of Iceland. Lyngbye avers in his Tentamen Hydro-
phytologice Danicce, 1819, that he saw on the Faroe Islands a portion
of a canoe made of mahogany. Gumprecht (p. 426) and Kohl (p. 159)
refer to Irminger's observation of masses of drift-wood on the west
side of the Faroe Islands. Drift-timber is also cast ashore on the
Shetland Islands,\which may hail from the tropics of the New World.
Mr. Fox sent me a piece of cedar ( ?) which was chopped from a baulk
about twenty-five feet long. It was honeycombed by the borings
of the Teredo, and was stranded on the west coast. We learn from
De Capell Brooke (p. 295) that much timber is beached on the
Norwegian sea border in the Tromsoe district and on Rost, and he
particularises Honduras mahogany. One may note in this connection
Pennant's statement that " part of the mast of the Tilbury man-of-
war, burnt at Jamaica, was taken up on the Western Coast of
Scotland " (A Voyage to the Hebrides in 1772).

Living Turtles carried by the Gulf Stream to the
Hebrides, the Orkneys, and the Shetlands. — This matter has
already been incidentally alluded to. Pennant in his Voyage to
the Hebrides in 1772 observes that " American tortoises, or turtle,
have more than once been taken alive on these coasts, tempest-
driven from their warm seas." Necker de Saussure in his paper in
the BihliotMque Britannique (1809), as quoted by Gumprecht (p. 416),
also mentions the stranding of turtles in connection with his sojourn
in this group. Mr. Peel in his book Wild Sport in the Outer Hebrides,
1901 (p. 3), tells us that young turtles together with West Indian
seed-drift are washed up on the shores of those islands. The Rev.
James Wallace, writing of the Orkney Islands at the close of the
seventeenth century, states that " sometimes they find living Tor-
toises on the shore " (1883 edition, p. 17). Some particulars of the
discovery of one of these turtles in the Shetlands are given by the
Rev. John Brand in his Brief Description of Orkney^ Zetland, etc''

WEST INDIAN DRIFT ON EUROPEAN SHORES 41

(Edinb. 1701, p. 174 of the 1883 edition). It appears that a specimen,
only about a foot in length, was found alive upon the sand in an
ebb " in the parish of Northmevan on the shore of Urie Firth. The
occurrence is characterised as a very rare event. From the remarks
of Mr. Peel and Mr. Brand it would seem that the turtles stranded
on the coasts of the Hebrides and the Shetlands are usually young
specimens. Turtles are often carried north from the Florida
Straits by the Gulf Stream. On one occasion the writer was on
board a steamer, bound north from the Bahamas to Philadelphia,
which, shortly after passing the Hatteras Lightship in 36° N. lat.,
nearly ran down a large turtle. It raised its head as if in astonish-
ment, and as it swept past the ship's side it was noticed that numerous
large Balani had established themselves on its back.

It may be here added that in the London Times for June 19,
1916, allusion is made to a large turtle, weighing nearly a ton, which
was taken alive a few days previously in a net off Scilly. In the
same net was captured a thresher-shark, nearly 12 feet in length, a
species frequenting the seas of temperate latitudes. The turtle, if of
West Indian origin, should have been accompanied by seed-drift
from that region ; but the writer has not since found any drift from
warm seas on the South Devon coast. (September 9, 1916. The
turtle proved to be the Leathery Turtle which breeds in the Danish
West Indies.)

Summary

1. In order to give point and method to the author's observations
on the dispersal of plants by currents in the West Indian region,
as illustrated by the examination of the beach-drift and by various
buoyancy experiments, the discussion is at first allowed to centre
around the fact that some of the materials reach the shores of Europe.

2. The literature of the subject goes back to the time of Clusius,
who first figured some of the fruits and seeds in his Exoticorum
Libri of 1605. Amongst those who interested themselves in the
matter, down to the close of the eighteenth century, were Peter
Claussen, the Norse writer (1632) ; Provost Debes in the case of the
Faroe Islands (1673); Petiver, the laborious compiler of the Gazo-
phylacium Naturce (1695); Sir Hans Sloane (1695-7); the two
Wallaces in the case of the Orkney Islands (1693 and 1700) ; Martin
in that of the Hebrides (1703) ; Pontoppidan, Bishop of Bergen (1751) ;
Gunnerus, Bishop of Trondhjem (1765); Strom, the Norwegian
naturalist (1766); Tonning, the pupil of Linnaeus (1768), and
Pennant in the case of the Hebrides (1790). Amongst the numerous
writers of the nineteenth century who have treated the subject in
more or less detail are Humboldt (1807); Necker de Saussure, who
sojourned in the Hebrides between 1806 and 1808; Sartorius von
Waltershausen in the case of Iceland (1847); Irminger, famous
for his investigations of the currents of the North Atlantic (1854) ;
Gumprecht, whose paper on the drift-products of the North Atlantic
(1854) is invaluable to all students of the subject ; Fogh in his paper
on the Gulf Stream (Copenhagen, 1857) ; Vibe, chief of the Norwegian

42 PLANTS, SEEDS, AND CURRENTS

General Staff Survey (1859-61); and Kohl in his history of the
Gulf Stream (Bremen, 1868). Among those who have specially
dealt with the botanical side of the subject in recent years are Lindman
(1883); Hemsley (1885); and Sernander (1901). The years named
refer to the date of the publication concerned, usually the earliest
when there is more than one (pp. 20-23).

3. Reference is then made to the popular names in Europe of the
West Indian drift seeds and to the superstitions connected with
them. One of the earliest designations was " Molucca Beans," a
name applied in Scotland and in the neighbouring islands (pp. 23-25).

4. A list is given of the twelve characteristic West Indian seeds
and fruits that have been recorded, as far as is known to the writer,
from European beaches and from the Azores, the localities being
tabulated (pp. 26, 27). The plants supplying them are in half the
cases leguminous. Those most frequently represented are Entada
scandens, Mucuna urens, and Guilandina honducella. Amongst the
most interesting are Sacoglottis amazonica and Ipomoea tuberosa
(pp. 26, 27.)

5. The records of West Indian drift seeds and fruits on the eastern
side of the North Atlantic, as far as they are known to the writer,
are then described under the headings of localities : the south-west
of England (p. 28); the south coast of Wales (p. 30); the west
coast of Ireland (p. 30) ; the west coast of Scotland and the Hebrides
(p. 31); the Orkney Islands (p. 32); the Shetland Islands (p. 34);
the Faroe Islands (p. 34) ; Iceland and Greenland (p. 35) ; the Scan-
dinavian coasts (p. 35), mention being made of the doubling of
the North Cape by seeds of Entada scandens (p. 36); the Azores,
four of the six kinds of seeds and fruits found here being recorded
from European beaches (p. 37); the Canary Islands and Madeira,
reference being made to the fact that although the writer has not
come upon any record of the occurrence of West Indian drift on these
islands the indications of bottle-drift point to its probability (p. 38).

6. The risks of premature generalisations on the dispersal of seeds
by the great ocean currents are then dwelt on, and a particular
instance is given. Since the seed itself can tell us little of its track,
the necessity is urged of looking elsewhere for evidence of the modes
of the working of the currents in transporting drift, and the writer
accordingly appeals to the evidence supplied by bottle-drift, a subject
to which the following chapter is devoted (pp. 39, 40).

7. The chapter concludes with remarks on the transport of logs
of mahogany to the coasts of Greenland, Iceland, and North-west
Europe, and on the stranding of living turtles on the shores of the
Hebrides, the Orkneys, and the Shetlands (pp. 40, 41).

BIBLIOGRAPHY

Baxjhin, C, Pinax Theatri Botanici, 1623. (He quotes on p. 405 the work of
Clusius (see below) as regards a drift seed since identified as belonging to
Ipomoea tuberosa.)

Bauhin, J., Historia Plantarum, 1650. (Quoted by Sir D. Morris in connection

with the drift fruits of Sacoglottis amazonica in Nature, January 31, 1889.)
BoRGESKN. See under Warming.

WEST INDIAN DRIFT ON EUROPEAN SHORES 43

Beand, J., A Brief Description of Orkney, Zetland, Pightland-Firth and Caithness :
Edinburgh, 1701. (Included also in Pinkerton's Voyages and Travels, 1809,
iii., 789. Reprinted at Edinburgh in 1883.)

Brooke, A. de Capell, Travels through Sweden, Norway and Finmark to the North
Cape in 1820 : London, 1823.

Claussen, p., a Description of Norway, 1632.

Clusius, C. (De I'Escluse), Exoticorum Libri Decern, 1605. (See Note 2 at the end
of this list.)

Dkbes, L. J., Fseroso og Faeroeske Indbyggeris Beskrivelse : Copenhagen, 1673.
(Another title " Faeroa Rescrata " is employed in the pages of Vibe and Fogh.
An English translation by J. S. (John Sterpin) was issued in London in 1676.)

Erslev, Tropical Drift on the Coast of Jutland, Det Danske Geografiske ; Selskab's
Tidskrift, Nos. 3 and 4, p. 79, 1877; and Petermann's Mittheilungen, xxiii.,
316, 1877.

Fielden, H. W., quoted by Hemsley in Annals of Botany, vi., 1892, concerning a

drift seed of Ipomoea tuberosa in the Hebrides.
FoGH, C, Golfstrommen, Tidskrift f. populcere Fremstillinger af Naturvidenskahen,

Copenhagen, 1857, vol. iv., ser. i. [Quoted at length by Vibe (see below).]

GuMPRECHT, T. E., Die Treibproducte der Stromungen im Nordatlantischen Ocean,
Zeitschrift fiir Allgemeine Erdkunde, No. 18, December 1854.

GuNNERUS, J. C, on Scandinavian drift in Det Trondhjemske Selbskabs Skrifter,
vol. iii. : Copenhagen, 1765.

Hemsley, W. B., Reports of the " Challenger " Expedition, Botany, vol. i., part iv.,
1885.

, Annals of Botany, vol. vi., 1892.

Hepworth, W. W. Campbell, The Gulf Stream, Geographical Journal, November
and December 1914.

Humboldt, F. H. A. von. Voyage aux regions equinoxiales, vol. i. : Paris, 1807, etc.

Irminger, C, on Iceland drift, Zeitschrift fiir Allgemeine Erdkunde, 1854, iii., 187.

JoNSTON, J., Historia naturalis de Arboribus et Fructibus, 1662. (Quoted by Sir
D. Morris in Nature, November 21, 1895.)

Kohl, J. G., Geschichte des Golfstroms und seiner Erforschung : Bremen, 1868.

Laughton, J. K., Physical Geography, 1873.

LiNDMAN, C, Om drifved och andra af hafsstrommar uppkastade naturforemal vid
Norges kuster: Goteborg, 1883. [Quoted at length by Sernander (see below).]

Lyngbye, H. C, Tentamen Hydrophytologiae Danicae, 1819. (In connection with
the Faroe Islands.)

Martin, M., A Description of the Western Islands of Scotland : London, 1703.
(Martin Martin was a native of the Hebrides and took his M.A. degree at Edin-
burgh in 1681. A second edition of his book was issued in London in 1716,
and a reprint of the first edition in Edinburgh in 1884. In a copy of the 1716
edition in the library of the British Museum there are marginal notes by
J. Toland and Lord Molesworth, written about 1720-21. Toland flourished
1670-1722. Martin's work is also included in Pinkerton's Voyages and Travels^
1809, iii., 572.)

Monaco, Prince of. The results of his experiments with floats in the North Atlantic
were published from time to time in the Comptes Rendus de V Academic des
Sciences between 1885 and 1892. Most of them were summed up in vol. cviii.
(1889) ; but he subsequently recovered some more floats, and this led to a further
summary with tabulation of results in vol. cxir. (1892).

Morris, Sir D., on the drift fruits of Sacoglottis amazonica, etc., in Nature, January
31, 1889, and November 21, 1895.

MijLLER, K., Les Merveilles du Monde Vegetal. [Not consulted. The work is quoted
in the English edition of Pouchet's UJJnivers (see below).]

44 PLANTS, SEEDS, AND CURRENTS

Neill, p., a Tour through some of the Islands of Orkney and Shetland : Edinburgh,
1806. [His references to Molucca Beans (pp. 60, 213) contain nothing that is
not given by the Wallaces and others.]

OsTENFELD. See Wabming.

Peel, C. V., Wild Sport in the Outer Hebrides, 1901. (There is a reference on p. Z

to West Indian drift seeds.)
Pennant, T., A Tour in Scotland and a Voyage to the Hebrides in 1772 : London,

1790. (Also included in Pinkerton's Voyages and Travels, 1809, iii., 289.)
Petiver, J., Musei Petiveriani : London, 1695 (octavo).
~ , Gazophyllacii Naturae : London, 1702 (octavo).

, Jacobi Petiveri Opera, Historiam Naturalem Spectantia aut Gazophylaceum :

London, 1764. A large folio work in two volumes containing 1000 figures
of natural history. The contents of all the plates are described with the
exception of the first fifty, the descriptions of which are given in the volume
of 1702.

PoNTOPPiDAN, E., Det forste Forsog paa Norges Naturlige Historic : Copenhagen,
1751. [An English translation was published in London in 1755.]

Pouchet, F. a.. The Universe, translated from the French by J. R. Ains worth Davis,
1906, p. 394. Dr. Karl Miiller in Les Merveilles du Monde Vegetal is quoted.

Robert, E., Voyage en Islande et au Groenland, sous la direction de M. Paul Gai-
mard, Mineralogie et Geologic, part i., p. 131 : Paris, 1840. (Reference is heie
made to the occurrence of seeds of Entada scandens at the North Cape and on
the shores of the White Sea. In this connection Gumprecht (p. 421) quotes
Robert in citing Le Bulletin de la Societe Geologique de France, xiii., 30.)

Saussure, Necker de, Voyage en ^Icosse et aux lies Hebrides, iii., 22 : Paris, 1821.
(With reference to the tropical drift of the Hebrides, Gumprecht (p. 416) quotes
a paper of this naturalist in the Bibliotheque Britannique, Sciences et Arts, 1809,
xlii., 90.)

ScHJdTH, A., Om enkelte af Ha vets Phanomene (On different Marine Phenomena) :
Christiania, 1848. Quoted by Vibe (see below).

Sernander, R., Den Skandinaviska vegetationens spridningsbiologi (The distri-
bution-biology of the Scandinavian plant-world), mit einem deutschen Resume :
Upsala, 1901. (An extensive bibliography is appended.)

SiBBALD, Sir R., Scotia Illustrata sive Prodromus Histories Naturalis Scotise : Edin-
burgh, 1694. (The earliest work known to the writer in which W^est Indian
seeds stranded on the shores of Scotland and of the neighbouring groups of
islands are designated " Molucca Beans.")

Sloane, Sir Hans, Catalogus Plantarum quae in insula Jamaica sponte proveniunt,
1696, p. 214, quoted by Sir D. Morris in Nature, November 21, 1895, and by
Gumprecht (p. 411).

, An Account of four sorts of strange Beans frequently cast on shore on the

Orkney Isles, Philos. Trans., xix., 298, 1695-7.
, A Voyage to the Islands of Madera, Barbados, Jamaica, etc., 1707 and 1725.

(Nearly all the work is occupied with " The Natural History of Jamaica," an

island where he sojourned about fifteen months, 1688-9.)
StrOm, Physisk og Oeconomisk Beskrivelse over Fogderiet Sondmor beliggende i

Bergens Stift i Norge : Soroe, 1766. (Quoted by Gumprecht on p. 420.)

Tabebn^montanus. See Note 2 at the end of this list.

ToNNiNG, Amoenitates Academicce, vii., 477. (A pupil of Linnaeus and the first botanist
who identified the tropical fruits and seeds cast up on Scandinavian beaches.)

Vibe, A., Kiisten und Meer Norwegens, in Petermann's Mittheilungen, Ereangzungs-
band, i., 1859-61.

Wahlenberg, G., Flora Lapponica, p. 506 : Berlin, 1812.

Wallace, Rev. J., A Description of the Isles of Orkney by Master James Wallace,
late Minister of Kirkwall, published after his Death by his Son : Edinburgh,
1693.

WEST INDIAN DRIFT ON EUROPEAN SHORES 45

Wallace, Dr. J., An Account of the Islands of Orkney by James Wallace, M.D.,
F.R.S. : London, 1700. (This writer is the son of the Rev. J. Wallace. The
work is his father's with additions, but without acknowledgment. In 1883
there was published at Edinburgh a reprint of the 1693 edition, edited by J. Small,
which included the materials added by the son in that of 1700.)

Waltershausen, Sabtorius von, Physisch-geographische Skizze von Island, 1847.

Warming, E., and colleagues. Botany of the Faeroes : Copenhagen, 1901-8.

Worm, 0., a Danish naturalist of the seventeenth century whose " Epistolae " are
quoted by Gumprecht (p. 420) in connection with Scandinavian tropical seed-
drift.

Note 1. — Gumprecht (pp. 421, 428-30) gives references in connection with drift-
wood stranded in high latitudes in the North Atlantic to Petherick, Olafsen, Povel-
sen, Crantz, von Lowenorn, de Pauw, Rennell, Irminger, Robert, Barrow, etc.

Note 2. — Though the " Exoticorum Libri " of Clusius are mentioned by old and
modern botanists in association with West Indian drift seeds, he merely described
and figured certain unknown fruits and seeds that had been given to him and sup-
plies no information about them. However, Gumprecht (p. 418) states that they
were also described and figured " in seinen Anmerkungen zu des spanischen Botanikere
Nicolas Monarde Bericht (Exotica, c. 49, p. 335) iiber die Pflanzen Westindiens."
He says the same {ibid.) of a botanical work of Tabernaemontanus, but gives no
reference.

Note 3. — Whilst this work was going through the press I have been able, through
the kindness of Miss U. Warren, to inspect two seeds, evidently sound, of Entada
scandens, which were found near Padstow on the north coast of Cornwall.

CHAPTER III

THE CURRENTS OF THE ATLANTIC AND THE TRACKS OF DRIFTING
SEEDS AS ILLUSTRATED BY BOTTLE-DRIFT

As indicative of the path followed by the drifting seed in its
passage across the Atlantic and of the time occupied in the ocean
traverse, the track of the drifting bottle offers very valuable data.
But it may be at once stated that there is no intention of dealing
here with all the materials which have accumulated in recent years
with reference to this subject. They are merely sampled in these
pages with the special object of throwing light on the interchange
of seed-drift between the Old and the New World. Notwithstanding
these limitations, the materials are quite as much as I can handle;
and any extension of the inquiry would result in the opening up of
the whole subject of bottle-drift, which would lead me far beyond
the limits set for this discussion.

One of the earliest to make a collection of bottle-drift data was
H. Berghaus, who, in 1837, in the first volume of his Allgemeinen
Lctnder und Volkerkunde, published a list of twenty-one bottle-drifts,
and laid down in a chart in his Physikalischen Atlas several interest-
ing examples. I have not had access to these works, and am
indebted to Schott for the reference. Shortly afterwards a chart of
bottle-drifts constructed by Daussy, a Frenchman, is stated to have
been published; but I have not been able to find it. It is men-
tioned by Kohl in his Geschichte des Golfstromes (1868); but the
author's name is given as Dayssy, and one is referred for particulars
to Nouvelles Annates des Voyages (tome Ixxxii., Paris, 1839), where
one finds only a brief notice of the results obtained. Schott (p. 2)
alludes to the missing chart, but he merely quotes Kohl. After
some search I found in Comptes Rendus (tome viii., p. 81, 1839) a
short paper of two and a half pages by M. Daussy, entitled " Sur les
observations de courants faites au moyen de bouteilles jetees a la
mer." He states that he had utilised ninety-seven bottle-drift
observations in his table and chart, which, however, do not accom-
pany his paper. Probably they lie among the unpublished records
of the Academic des Sciences of Paris.

Major Rennell, in his Investigation of the Currents of the Atlantic
Ocean (1832), deals with the subject, and especially with the bottle-
drift from high northern latitudes, many interesting examples being
given. In 1852 Commander Becher published in the Nautical
Magazine, with charts, the data for about 180 bottle-drifts in the
North Atlantic, two-thirds of which had been previously published

46

CURRENTS OF THE ATLANTIC 47

in the same journal for 1843. These results, where suitable, have
been utilised by me. However, most of my materials have been
supplied from the results <]fathcred in recent years by the United
States Hydrographie Offiee in Washington and by the Deutsche
Seewarte in Hamburtr. The first were published on the backs of
the North Atlantic Pilot Charts, while the second were embodied in
Dr. Schott's memoir Die Flaschenposten der Deutschen Seewarte y
1897. By far the most extensive and systematic inquiry ever made
in this direction was that conducted by Albert, Prince of Monaco,
from 1885 to 1887. Floats, specially devised, were employed; but
the mode of presentment of his results and the absence of his chart
have stood in the way of my employing them as much as I could
have wished. As will be seen from the following pages, however,
they have proved of great value.

Whilst my facts for the North Atlantic are mainly derived from
the American Pilot Charts and for the South Atlantic from Dr.
Schott's work, those for the equatorial seas are chiefly derived from
both these sources and to a less degree from the Nautical Magazine.
With great courtesy the U.S. Hydrographic Office supplied me
with a set of four bottle-drift charts, covering the eight months
from October to May 1900-8, and affording the data and tracks
for about 650 bottles. Dr. Schott, whilst preparing his memoir,
had at his disposal the materials for 643 bottle-drifts in the Atlantic,
Indian, and Pacific Oceans. Of these 452 are concerned with the
North Atlantic and 102 with the South Atlantic, forty-three with
the Indian Ocean, and forty-six with the Pacific Ocean. The tracks
for most of the Atlantic bottle-drifts are laid down in his charts.
Thus in the ease of the North Atlantic about three-fourths are thus
laid down. The tracks of all those in the Indian and Pacific Oceans
are represented in separate charts, and some highly interesting data
are given for a few bottles in the belt of the Westerly Winds in high
southern latitudes. But the weak point in the memoir is the deficient
supply of facts relating to the duration of each drift. In this respect
Dr. Schott only samples the subject, referring the reader for the
complete data to the Archiv der Seewarte and the Annalen der Hydro-
graphie. However, sufficient materials are given in his pages for the
elucidation of this part of the inquiry.

With regard to the Prince of Monaco's investigations during three
voyages in the North Atlantic, 1885-7, it may be said that in the
first voyage (1885) 169 floats were dropped into the sea to the north-
west of Corvo in the Azores. In the second (1886) as many as 510
floats were cast over about midway between the Azores and South-
western Europe along a line, 450 miles in length, nearly on the
meridian 17° 40' W. of Greenwich and between the latitudes of
42° 32' and 50° N. In the third voyage 931 floats were thrown over
between the Azores and the Banks of Newfoundland and sixty-five
to the north of those islands, at average intervals in most cases of
1180 metres, along a Hne 700 miles in length. Out of this total of
1675 floats, 226, or 13 J per cent., were recovered. From time to
time, between 1885 and 1892, the results were given to the world in
the Comptes Rendus hebdomadaires des Sciences. Most of them were

48 PLANTS, SEEDS, AND CURRENTS

summed up in Vol. CVIII. (1889) ; but fifty-six floats were afterwards
returned, and this led to a final summary and tabulation of results
in Vol. CXIV. (1892). This final report is said to have been accom-
panied by a chart in which the Prince of Monaco laid down the
tracks of all of the recovered floats. This chart, to my great dis-
appointment, I failed to find. Reference to these very important
investigations has been made in various English journals, such as
Nature and the publications of the Royal Geographical Society.
The Prince himself contributed a general account of his results to
the Proceedings of the Society just named for 1892 in a paper
entitled " A New Chart of the Currents of the North Atlantic."
He read a paper before the British Association in 1892, but it is not
given in the Annual Report. His results will be utilised, as occasion
requires, in the succeeding pages ; but it may be here observed that
these floats were stranded on all the eastern shores of the North
Atlantic from the North Cape to Morocco. About 9 per cent, of the
recoveries were returned from the Canary Islands and about lOJ per
cent, from the West Indies and Central America. The reader will
perhaps be surprised at the large number of these floats that reached
the tropical regions of the New World, and this will prepare him for
much that follows in the succeeding pages of this chapter.

The Value of Bottle-drift Data for the Study of the
Dispersal of Seeds by Currents. — I will not enter here into the
old controversy as to the value of bottle-drifts for the investigation
of currents. Here, as in most other controversial matters, the via
media between wholesale condemnation and uncritical acceptation
may be confidently pursued. We are only now concerned with the
surface-flow, which is all that the currents signify for us in the
transport of floating materials. Although, as the compiler of the
American charts remarks, the individual drifts are but the resultant
effect of all the forces to which the bottle is exposed during its
passage, yet, as he goes on to say, the tracks followed by these float-
ing bottles furnish a fair conception of the drift-currents. When
we look at the American and German charts and notice how uniform
and consistent is the direction taken by bottles cast into the sea
within the limits of well-known currents like the Gulf Stream and the
Main Equatorial Current, it would be idle to cavil at the assumption
that they are transported by these currents. The water-logged
derelict from off Cape Hatteras, the baulk of mahogany from West
Indian waters, the living turtle from the warm latitudes of the New
World, the floating bottle containing the record of its start in Cuban
waters or in Florida seas, the buoyant seed that could only have
grown in the West Indian islands or on the tropical mainland of
America, all tell the same story when they reach the coasts of
Europe.

The Proportion of Recoveries. — Naturally, the proportion of
recoveries among ordinary bottles is small; but much depends on
locality. Dr. Schott especially alludes to this matter (p. 3, etc.).
The proportion may be as high as 10 per cent, in the case of bottles
dropped overboard in the warm latitudes of the middle of the
Atlantic, whence they are borne westward to the West Indies; and

CURRENTS OF THE ATLANTIC 49

when conspicuous, specially devised floats are used, as with the
Prince of Monaco's investigations in the North Atlantic, it may be
as much as 13J per cent. Very few bottles are returned from the
West African coasts, and the same may be said of those thrown
over in high southern latitudes. In the last case the rare recoveries
possess a high interest. Thus out of sixty bottles dropped over-
board by Dr. G. Neumayer during a voyage in 1864 from Australia
to the equatorial Atlantic by Cape Horn, only one was recovered
after a lapse of four years, and that was a bottle that was drifted
from Cape Horn to South-east Australia (Schott, p. 2). A similar
experience is recorded in the London Times for April 17, 1912. Of
forty bottles dropped overboard during a voyage in 1908 from
London to Melbourne by the Cape of Good Hope, only one record
was returned, and that was concerned with a bottle which was
washed up on the coast of Chile, after drifting from a position
lying some hundreds of miles to the south-west of Cape Leeuwin,
Australia.

The Difficulties connected with the Delay in the Recovery
OF the Bottles. — These difficulties prove to be not so great as at
first they seem to be. The belated " finds " become very evident
when one handles numerous data for the same drift-passage ; and at
times the records for a set of bottles dropped over at or near the
same time display internal evidence of critical value. Thus, if the
one that has travelled the longest distance is found first, it is fair to
infer, in the case of transatlantic drifts, that the delay in its recovery
was relatively short. As explained in a later page, in order to
eliminate this disturbing element as much as possible, I have utilised,
when estimating the average drifting-rate for a particular traverse,
only the records for the bottles with the quickest rates up to 20 or 25
per cent, of the total. I have since ascertained that the Prince of
Monaco adopted a similar method in determining the mean velocity
of the " drifts." When they were numerous, he took the average of
the fastest third or fourth. When they were few, he selected the
most rapid example. At times the remark of the finder that the
bottle appeared to have been stranded at the last tide is very service-
able; but the record is particularly valuable when, as occasionally
happens, the bottle has been found afloat.

The Tracks of Bottles thrown Overboard together. —
Interesting results are supplied by the American charts in the cases
of bottles thrown over together off the eastern coasts of the United
States. They may be distributed fanwise, and are then cast ashore
on the coasts of Europe in places far removed from each other, or
they may be recovered on the European side only a few miles apart.
Thus, out of eight bottles thrown together into the sea off Cape
Hatteras from the s.s. New York on March 24, 1906, one was found
on the coast of Scotland, two on the Irish coast, two near Arcachon
on the shores of the Bay of Biscay, one in the Azores, one in the
Bermudas, and one on Grand Turk at the southern end of the
Bahamas. As an example of bottles drifting in company across
the Atlantic, I will take the case specially noted in these charts.
From the s.s. Cherokee two bottles were put overboard together near

E

50 PLANTS, SEEDS, AND CURRENTS

Cape Hatteras on October 26, 1905, and they were recovered on
June 10 and 19, 1907, in the vicinity of Bray Head and Cape Clear
on the south-west shores of Ireland, about fifty miles apart as the
bird flies. A very remarkable instance of this kind is recorded by
Mr. Wood-Jones in the Indian Ocean, though there was here an
unexplained delay in the recovery of one of the bottles. Two bottles,
dispatched on November 15, 1905, from Keeling Atoll, were found
at " exactly the same spot " at Brava on the coast of equatorial
East Africa in 1° 6' N. lat. The first was recovered on May 27,
1906, and the second on July 11, 1907 (Coral and Atolls y pp. 294-5,
1910). It is probable that these two bottles drifted together and
that from some cause the second was overlooked.

But this is the exception and not the rule. Rennell, in his book
on the Atlantic currents, refers to two bottles thrown over from
H.M.S. Newcastle on June 20, 1819, rather over 300 miles south-east
of Cape Cod in localities about twenty miles apart, one of which was
picked up on May 20, 1820, on the north coast of San Jorge in the
Azores, and the other near the island of Aran on the north-west coast
of Ireland on June 2, 1820, the difference in latitude represented by
the divergence of the two tracks being about sixteen degrees. [These
two cases are included by Becher in his list of bottle-drifts in the
Nautical Magazine for 1852 (Nos. 97 and 98), but the positions there
given of the starting-places are about sixty miles apart.] The
separation of bottles thrown over together may be soon effected,
even where there is no reason to suspect the presence of contiguous
currents. Schott (p. 18) alludes in this connection to Hensen's
experiment in Kiel Bay with ten weighted glass globes, which after
twenty-four hours displayed an extreme separation of a German
mile (nearly five English miles). Of course, when the bottles are
dropped overboard in the disputed area between two contrary cur-
rents, as in the case of the Main Equatorial Stream and the Guinea
Current, great divergencies are to be looked for. A striking instance
is mentioned in Note 19 of the Appendix. Of two bottles that were
cast over together in the vicinity of St. Paul's Rocks in the middle
of the Atlantic, one was thrown ashore on the coast of Sierra Leone
and the other on the shores of Nicaragua.

The Divergent Tracks of Derelicts and Casks. — ^Derelicts
display some curiously divergent courses in the North Atlantic.
Reference is made in Notes 15 and 16 of the Appendix to two dere-
licts which commenced their drifting passage within sixty miles of
each other, about 200 or 250 miles north of Cape Hatteras, at the
same season (February and March), but in different years. One was
stranded in the Hebrides and the other on the Panama Isthmus,
after periods of ten and eighteen months respectively. Water-
logged derelicts are especially instructive, since their position at
different stages of their track is often determined by the observations
of passing vessels. In the Nautical Magazine for 1843 (p. 757) and
1852 (p. 672) allusion is made to the drift of some casks of blubber
from the ship William Torr that was wrecked in Davis Straits. As
they were carried eastward and southward towards Ireland and the
north of France they became more and more separated, so that

CURRENTS OF THE ATLANTIC 51

after crossing the 20th meridian of west longitude, a drift probably
of at least 1500 miles, the most northerly and southerly casks were
nine or ten degrees of latitude apart.

The Circulatory Movement of the Surface-waters of the
North Atlantic. — Broadly viewed, to adopt the standpoint of the
Prince of Monaco, this movement has its centre somewhat to the
south-west of the Azores. The circumferential waters, after skirting
the eastern shores of North America, cross the ocean to the shores of
Europe, and then bending south along the African coast, curve west
in the vicinity of the Cape Verde Islands and follow the line of the
North Equatorial Current to the West Indian region. Between the
tracks involved in a very long circuit at the circumference of the
movement and a very short one around its centre several inter-
mediate tracks are possible for drift.

With these preliminary remarks I will at once proceed to deal with
the evidence of the drifting bottle, and it may be here said that it is
with the long outer circuit of the North Atlantic that the tracks of
the bottles laid down in the American and German charts are mainly
concerned. They represent the course followed by West Indian
drift in reaching Europe, and the course that would be afterwards
pursued by the same drift in returning to the West Indian region,
or by European and West African drift in reaching the New World.
A large segment of this circuit did not come within the area covered
by the Prince of Monaco's investigations, namely, that lying between
the West Indies and a line uniting Newfoundland with the Azores.
It is here that the materials supplied by the American charts are
most valuable.

Whether the circuit is accomplished by the same bottle or by
different bottles the indications are the same. Even if it cannot
often be absolutely demonstrated by one example (see Note 15 of the
Appendix), the circuit of the North Atlantic can be illustrated in
piecemeal fashion by the records of two or three examples. Leaving
the warm waters of the West Indian seas, the drifting bottle would
be carried swiftly by the Gulf Stream through the Straits of Florida,
whence it would be borne northward past Cape Hatteras to the
parallels of 40° to 45° south of Cape Race. Then, coursing eastward,
it would, on approaching the 40th meridian of west longitude, come
to a parting of the tracks. Whilst the great bulk of the drift would
continue its easterly course towards the shores of Europe, a portion
would be deflected south to the Azores. Much of this would be
stranded on these islands, but much also would traverse the group,
and after passing well to the westward of the Canaries would come
within the influence of the North Equatorial Current, ultimately
reaching the Bahamas or the Florida coasts, or even the Bermudas.
But our interest lies with the fate of the great mass of the drift.
Continuing its easterly course, but with a northerly trend, most of
it would be spread out fanwise and would be distributed over the
whole length of the western shores of Europe from the North Cape
to Cape St. Vincent, even reaching Morocco. Yet a small portion of
it would keep to the open ocean. Carried south in the Portuguese
Current, it would leave samples of its materials on the beaches of

52 PLANTS, SEEDS, AND CURRENTS

Madeira and the Canary Islands, and after approaching the vicinity
of the Cape Verde Group it would get into the full stream of the
North Equatorial Current, and thus be borne to the West Indian
region. Whilst, as already indicated, the conclusions for the first
portion of this circuit are mainly based on the American charts,
those for the remainder are also founded on the Prince of Monaco's
results. With these introductory remarks I will first deal with the
traverse of the North Atlantic by drift from the American to the
European side of the ocean, and afterwards with the return passage
from European and African waters to the West Indian region.

The Passage of Bottle-drift from the West Indies and the East Coasts
OF North America to the Shores of Europe

TABLE I

The traverse from the West Indies to the shores of Europe

(Compiled from the American, German, and English sources above named. The
columns A, B, C, D, indicate not only the starting-places of the bottles, but also
the track pursued by them in the passage from the New to the Old World. The
circuit of the North Atlantic is also illustrated by those bottles, which, on approach-
ing the shores of Europe, were deflected south, and after passing through the Canary
Islands, were returned to the West Indian region in the North Equatorial Current.)

Locality ^rhere thrown Overboard

A

C

D

Place of Recovery

Region
between
Florida,
Cuba, and
the Bahamas
(21°-27°
N. lat.)

Vicinity of

Cape
Hatteras

N. lat.)

Region
south of
Sable Island
and Cape

Race
(40°-45»
N. lat.)

Region in
mid- Atlantic
lying N.W.
of the
Azores
between
30° and 40"
W. long, and
45° and 50°
N. lat.

Total

Per-
centage

Iceland .
Norway .
Sweden .
Shetland Islands
Orkney Islands .
Scotland and the

Hebrides .
Ireland .
England .
France
Portugal .
Azores
Morocco .
Madeira .
Canary Islands .
West Indies .
Bermuda

1

1

3
2
2

1

-
1
1
1
1

6
7
1

8

9
1

2

1
1

3

10
4
2
2

8
2

2

1

1

3

2
5

8

2

1

1

2
5
1
1

2

12

25
7

20
2

20
3
1
2
3
1

2

4-5

1

1

2

11
23

6-5
18-5

2

18-5
3
1
2
3
1

10

38

36

23

107

100-0

CURRENTS OF THE ATLANTIC 53

The Passage of Bottle-drift from the West Indies and the East Coasts
OF North America to the Shores of Europe (continued)

TABLE II

The results of the researches of the Prince of Monaco

(The specially devised floats employed were deeply immersed and were thus le?s
likely to be directly influenced by the wind than the ordinary bottle as usually em-
ployed. Only the latter part of the traverse from the West Indian region to the
shores of Europe is here illustrated, namely, the portion east and north of a line
drawn from the Azores to the Banks of Newfoundland. Quite two-thirds of the
floats were dropped into the southern half of the area traversed by the Gulf Stream,
using that term in a general sense ; and this explains the large percentage of floats
that were deflected south to the Canaries and ultimately reached the West Indies
in the North Equatorial Current.)

Locality

where thrown Overboard

B

C

(1885)

/-I QQ7\

North-west of

Place of Recovery

the Azores.
(Along a line
stretching

Between the
Banks of New-

the Azores.
(Between

Total

Per-
centage

from 117 to

foundland and

42° 30' and

270 miles

the Azores.

50° N. lat.

N.N.W. of
Corvo, lat.

(Along a line
joining these

and along the
meridian

41°-44° N.,
and long.

two localities.!)

17° 30' W.)

32°-33° W.)

Iceland ....

3

3

1-3

Norway ....

22

22

10

Denmark ....

1

1

0-5

Scotland, Hebrides,

Orkneys, Shetlands

9

9

4

Ireland ....

18

18

8

England ....

2

2

1

France ....

12

24

36

16

Spain and Portugal .

1

12

18

31

14

Azores ....

11

26

37

16-5

Tunis

1

1

0-5

Morocco ....

1

6

7

3

Madeira ....

1

5

6

2-7

Canaries ....

1

14

6

21

9-6

West Indies .

4

13

6

23

10-5

Yucatan ....

1

1

0-5

Bermuda ....

3

1

4

2

18

142

62

222

100-0

The Passage of Bottle-drift from the West Indies and the
East Coasts of North America to the Shores of Europe. — This
traverse is well illustrated in the two tables above, about which a
few explanatory observations may here be made. Three-fourths of
the materials employed in the first table are furnished by the Pilot

* The Prince of Monaco includes in these results a small group of floats (about an
eighth of the total) dropped overboard due north of the Azores between the positions
49*' 31' N. and 29** 7' W. and 48° 68' N. and 26-7 W.

54 PLANTS, SEEDS, AND CURRENTS

Charts of the North Atlantic pubHshed by the United States Hydro-
graphic Office for the eight months October to May 1900-8, the
rest being suppHed by Dr. Schott's memoir Die Flaschenposten der
Deutschen Seewarte (1897), the Nautical Magazine for 1852, and in a
few cases from sundry sources. The second table deals with the
results of the researches of the Prince of Monaco, and have been pre-
pared from his papers in the volumes of the Comptes Rendus from
1885 to 1892.

In the first table there are given the records for 107 bottles that
started from the four regions A, B, C, D in their traverse of the
North Atlantic. Since all the four starting-places lie in the main
track of the drifting bottles from the tropics of the New World to
the shores of Europe, the limits being determined by the data them-
selves, it follows that all the materials in this table may be used to
illustrate the passage of West Indian bottle-drift to the shores of
Europe. But this table tells us more. It tells us of the bottles that
were deflected south when approaching European waters, and were
ultimately returned to the West Indian region in the North Equatorial
Current. In other words, it also illustrates the completion of the
circuit of the North Atlantic. With this last, however, we are not
here specially concerned, except in so far as it informs us of the
distribution of bottle-drift that leaves West Indian waters on its
transatlantic passage.

The course pursued is determined by the Gulf Stream. After
emerging from the Florida Strait, the bottles are borne northward
by this current past Cape Hatteras towards Nova Scotia and New-
foundland, and then eastward with a northerly trend towards Europe,
spreading out in a fan-like fashion after crossing the 40th meridian
of west longitude to the north-west of the Azores. About 18 per
cent, of the bottles dealt with in the table were soon diverted south
and stranded on the Azores, but by far the greater number, amount-
ing to about 75 per cent., were distributed over all the exposed
coasts from the North Cape of Norway to Morocco. The remaining
seven of the hundred bottles, still speaking of them in a proportional
sense, were borne in the Portuguese or North African Current yet
further south. One was beached on Madeira, two on the Canary
Islands, and four came within the influence of the North Equatorial
Current and were ultimately recovered in the Lesser Antilles, the
Bahamas, and the Bermudas. Of those just mentioned as reaching
the West Indian region, one from the middle of the North Atlantic
was picked up in the Turks Islands at the south-east end of the
Bahamas, whilst two from off Cape Hatteras were found respectively
on the island of Anguilla in the Lesser Antilles and on that of Eleu-
thera in the North-west Bahamas, the circuit of the North Atlantic
being almost completed in the last case.

It may here be observed that the fan-like distribution of bottle-
drift from the New World on the coasts of Europe, though naturally
most pronounced when we lay down on a chart the tracks of numbers
of bottles from the same locality covering a period of several years,
is also well exhibited in the case of bottles thrown over together.
This is well exemplified in the case of bottles that begin the ocean

CURRENTS OF THE ATLANTIC

55

traverse in the vicinity of Cape Hattcras. If we take a period of
years, they may be distributed, as shown in the preceding table,
over the whole stretch of seaboard from the north of Norway to
Morocco, which represents a range of about forty degrees of latitude.
These bottles were dropped over not only in different years, but in
different seasons and within an area covered by two degrees of
latitude. One could scarcely expect such a divergence of tracks in
the case of bottles thrown overboard together off the same headland.
Yet it may be large; and in this connection reference may again be
made to the divergence of the eight bottles thrown over together off
Cape Hatteras (see p. 49). Of the five thrown up on the shores of
Europe, the extreme range in latitude was almost eleven and a half
degrees, the northernmost being cast up on the island of Colonsay off
the west coast of Scotland and the southernmost on the shores of the
Bay of Biscay in the vicinity of Arcachon. Yet we have to assume a
much greater divergence for the whole group of bottles, since three of
them were deflected south and were recovered on the Azores, the
Bahamas, and the Bermudas.

Various disturbing influences doubtless affect in different years
and seasons the distribution of drift from the New World in its
traverse of the North Atlantic. But of this we may be assured that
there is no one tract of seaboard on the European side that receives
all its transatlantic drift from the same region of the New World.
The Irish coasts receive drift from all latitudes on the American side
of the North Atlantic between the Caribbean Sea and Davis Strait.
So also the North Cape of Norway receives drift aUke from the
Greenland coasts, from off Cape Hatteras, and from the Florida seas.
For particulars relating to bottle-drift from Davis Strait and the
south end of Greenland reference may be made to the concluding
remarks of Note 27 of the Appendix.

Coming to the Prince of Monaco's results in the second table, it
may be at first observed that they only lend themselves in part for
the discussion of the traverse of the North Atlantic from the New to
the Old World, since they are not concerned with the first half of the
passage from the Florida Straits to a line drawn from the Newfound-
land Banks to the Western Azores, and even with this limitation
their indications mainly apply to the southern portion of the drift
that the Gulf Stream bears eastward towards Europe. But what
we lose in one way we gain in another, since they offer a splendid
illustration of the circulatory movement of the surface-currents of
the North Atlantic, which formed one of the principal objects of this
unrivalled series of investigations. It will be observed that the
results for 1885 and 1886 mainly illustrate this southern divergence
of the drift, which begins to the north-west of the Azores and is
continued until after the 20th meridian of west longitude is crossed.
Of the eighty floats recovered in these two sets of observations, not
one was found north of the coasts of France, and ten of them, or a
proportion of 12 J per cent., were returned to the Prince of Monaco
from the West Indies. This is four times as great as that represented
in Table I. for bottles that in reaching the West Indian region have
practicaUy performed the circuit of the North Atlantic; and it

56 PLANTS, SEEDS, AND CURRENTS

should be noticed that the proportion of bottles stranded on Madeira
and the Canaries is tripled in the case of the Prince of Monaco's
floats thrown over in 1885 and 1886.

The Prince's results for 1887 are most suited for comparison with
those of Table I. But even here it is obvious that if we make a
cross-section of the Gulf Stream drift in mid- Atlantic, these results
are more concerned with the southern half than with the northern
half of the section. Thus the great increase in the proportion of
floats deflected towards warm southern latitudes is here repeated,
about 13 per cent, being carried to Madeira and the Canaries and
about 10 per cent, to the West Indian region. This tendency is well
exhibited in the differences in the two cases between the proportions
of bottles or floats stranded on the European side of the Atlantic in
latitudes north of the French coasts. This proportion in the case of
the results given in Table I. is as much as 51 per cent., whilst for the
results obtained by the Prince of Monaco for 1887 it is barely 39
per cent.

With these exceptions, most of the principal features in the dis-
tribution of transatlantic drift that are illustrated in Table I. are
reproduced in the Prince of Monaco's results. His floats were found
on all coasts of the European side of the North Atlantic from Norway
to Morocco, and they even penetrated into the Mediterranean. It
may be added that the large proportion of the floats recovered in
Norway in the series of experiments made in 1887 is to some extent
counterbalanced by the diminished proportion found on the coasts of
Ireland and Scotland, inclusive of the islands near.

The Passage of Bottle-drift from the European and African
Side of the North Atlantic to the West Indies. — This has
already been demonstrated by implication from the data in the
previous tables that are employed to establish the completion of the
circuit of the North Atlantic by drifting bottles and floats. But we
will here deal with those bottles that commence the ocean traverse
in European or African waters, or in different parts of the track to
the New World; in other words, with those that perform the last
half of the circuit. As before observed, bottle-drift in European
waters is carried south in the Portuguese or North African Current
past Madeira and Canary Islands to the vicinity of the Cape Verde
Group, whence it is borne westward in the North Equatorial Current
to the West Indies. Before discussing this subject I will give the
materials on which my conclusions are based (see table, p. 57).

Although the table largely explains itself, some additional remarks
may here be made; and in the first place I will give a few details
about the places of recovery." Most of the bottles entered in
Column A, under the heading " Bahamas," were recovered at the
south-east end of the Bahamian group, namely, on the Turks, Caicos
and adjacent islands. Out of the twenty-six there recorded, twenty
are thus accounted for. Two were found in the middle of the group
and four at the north-west extremity. Of the twenty bottles found
in the Greater Antilles, as given in Column B, four were stranded on
the south coast of Jamaica and on the small islands near, whilst all
the rest were beached on the coasts of Cuba, Hispaniola and Porto

CURRENTS OF THE ATLANTIC 57

Table Illustrating the Passage of Bottle-Drift from the European
AND African Side of the North Atlantic to the West Indies

There are here shown the places of recovery in the West Indies and on the
American mainland of bottles thrown over in most cases on the eastern side of the
North Atlantic between the south-west of Ireland and the Cape Verde Group and
transported across the ocean in the North Equatorial Current.

(The materials are derived from the bottle-drift charts of the U.S. Hydro -
graphic Office for October to May 1900-8, from Dr. Schott's Die Flaschenposten der
Deutschen Seewarte, 1897, from Commander Becher's papers in the Nautical Magazine
for 1852, from Major Rennell's Investigation of the Currents of the Atlantic Ocean^
1832, etc. ; the two first named being the principal sources.)

' Places of Recovery

A

B

C

D

E

F

m

to eS

Starting place

Bahams

Greatei
Antillei

Lesser
Antillei

w S

« <=>
2

oS

Florida

Total

Remarks

Off the S.-W.
coast of Ireland

1

1

From the
land 260 miles

Off the coasts
of Spain and Por-
tugal

2

2

9

1

14

Within the
region 36°-45°
N. lat., 9°-20°
W. long.

Vicinity of Ma-
deira and the
Canary Islands

6

6

3

2

17

About midway
between the Can-
ary and Cape
Verde Islands

3

4

3

4

1

1

16

Vicinity of the
Cape Verde Is-
lands

7

4

13

5

3

32

Within the
region 11°-19°
N. lat., 21°-
30° W. long.

Mid-Atlantic,
about half-way
between Cape
Verde and the
West Indies

7

4

12

2

25

Between 13°
and 21° N. lat.
and 35° and
50° W. long.

Totals . . .

26

20

40

12

3

4

105

Percentages .

25

19

38

11

3

4

100

Note. — The percentages may be taken as illustrating the distribution of drift carried
by the North Equatorial Current to the tropics of the New World from the European
and African side of the Atlantic.

58 PLANTS, SEEDS, AND CURRENTS

Rico. In the cases of Cuba and Hispaniola they were found in about
the same proportions and equally distributed on both the north and
south sides of the islands. Those mentioned under Column C were
well distributed over the Lesser Antilles north of Barbados and
St. Vincent, and, with the exception of one stranded on the Grena-
dines, never south of those two islands. Of the remainder it may
be said that most of those brought to the shores of Honduras and
Nicaragua were found in the former region, that those carried
through the Straits of Yucatan into the Gulf of Mexico were either
cast up on the coasts of Texas and Louisiana or were hurried along
in the Gulf Stream and deposited on the east coast of Florida.

Taking the bottles starting from the eastern side of the ocean, no
consistent discrimination can be made between the groupings of the
places of recovery and the starting localities. As far as the data go,
they show that almost from every one of the localities bottles may
be transported all over the West Indian islands north of Barbados
and St. Vincent. South of these two islands is the track by which
the drift of the Main Equatorial Current chiefly enters the West
Indian region ; whilst on the north, extending as far as the Bahamas,
lies the area that receives the drift of the North Equatorial Current.
It is with the distribution in the West Indian region of the drift
brought across the North Atlantic by this current from latitudes,
generally speaking, north of the tenth parallel (N. lat.) that the
table above given is exclusively concerned. The concentration of
drift at the south-east end of the Bahamas is remarkable. One-
fifth of all the bottles brought by the North Equatorial Current to
the West Indian islands was stranded on the Turks, Caicos and
neighbouring islands.

The noticeable proportion of bottles stranded on the east coast of
Florida, after being thrown over in the vicinity of the Canary and
Cape Verde Islands, is a feature of the foregoing table. Those that
have crossed the Caribbean Sea, after passing through the islands of
the Lesser Antilles, often strike the coasts of Nicaragua and Hon-
duras; but almost as many pass to the northward through the
Straits of Yucatan, and, if not beached on the north-western shores
of the Gulf of Mexico, enter the Florida Straits and are thrown up,
as in the case of these bottles, on the east coast of Florida. The
story of the bottle-drift cast up at different stages of the long passage
from the African side of the North Atlantic to the Florida seas
clearly indicates the track across the Caribbean Sea and the Gulf of
Mexico; and both the American and German authorities are at one
on this point. At the same time it is evident that occasionally the
Florida waters may be reached by the shorter route through the
Bahamas by the agency of the Antillean Stream, a subject referred
to later on in this chapter and in Note 13 of the Appendix.

It is to be expected that bottles which reach the Florida seas,
after drifting across the North Atlantic from the African side, would
sometimes be caught in the rapid current of the Gulf Stream in the
Florida Straits and be carried northward and eastward to the coasts
of Europe. It is brought out in the previous tables (pp. 52, 53)
that this is not infrequent with bottles dropped overboard in the

CURRENTS OF THE ATLANTIC 59

Florida region; and we have a good example in the case of those
from the African side numbered 206 in Schott's memoir (map ii.,
pp. 9, 23, 26). Starting from a position about 150 miles south-west
of the Cape Verde Islands (lat. 13° 16' N., long. 25° 51' W.) on May 19,
1887, it was recovered at Clifden, on the west coast of Ireland (Co.
Galway), on March 17, 1890. The distance traversed in its passage
in the North Equatorial to the West Indies, and thence to Europe
in the Gulf Stream drift, was computed at 7700 miles by the southern
route through the Lesser Antilles and then across the Caribbean Sea
and the Gulf of Mexico, and at 6300 miles by the more direct northern
passage between the Bahamas and the Greater Antilles. Dr. Schott
gives a facsimile of the paper enclosed in the bottle, duly filled up
and signed by the sender and the finder. It is not possible to deter-
mine which of the two routes in West Indian waters this bottle
pursued; but that drift from the Caribbean Sea may reach the
shores of Europe is indicated by the track of a bottle (No. 110) in
the Nautical Magazine for 1852. It was thrown over about a hundred
miles off the south coast of Jamaica in lat. 16° N. and long. 78° 5' W.,
and was found on the coast of Ireland ; but the time occupied in the
drift is not supplied. Such are some of the principal indications
afforded by bottle-drift of the work that would be performed by the
North Equatorial Current in carrying seed-drift from the Old to the
New W^orld.

However, some curious questions arise in connection with the
debatable region of the Guinea Current. To the southward of the
Cape Verde Group and confined between the parallels of 2° S. and
10° N., and between the meridians of 20° and 32° W., lies a region in
which the bottles become the sport of conflicting currents. Here
the Guinea Current flowing east is interposed between the North and
Main Equatorial Currents flowing west, and, owing to the shifting
boundaries of the several streams, bottles cast over at the same spot
may be carried to opposite sides of the Atlantic. Dr. Schott (pp. 10,
18; map i.) gives the case of two bottles thrown together into the
sea a little north and east of St. Paul's Rocks, one being recovered on
the coast of Sierra Leone and the other on the shores of Nicaragua.
In the same note of the Appendix (Note 19) in which the details of
these remarkable drifts are given, reference is made to the possibility
that under certain conditions seeds may be transported from the
coasts of North Brazil to the shores of Sierra Leone and Liberia in
the counter-current formed at certain seasons by the westward
extension of the Guinea Current. This is probably a rare event, but
a particular example of bottle-drift is mentioned in this connection.
With this exception, no opportunity of American seed-drift reaching
Africa across the tropical latitudes of the North Atlantic is indicated
by the numerous bottle-drift data at my disposal.

The Currents of the South Atlantic. — Before proceeding to
deal with the passage of bottle-drift across the South Atlantic in the
Main and South Equatorial Currents, I will state the view of the
currents in this ocean that is adopted in these pages. It seems
usual to speak in a collective sense of the Southern Equatorial
Current as dividing, when approaching Cape St. Roque, into the

60

PLANTS, SEEDS, AND CURRENTS

Guiana Current, running northward to the West Indies, and the
Brazil Current (the smaller of the two), flowing southward along
the coast of South Brazil. But by some the distinction is made in
mid- Atlantic between the Main Equatorial Current, which is known
as the Guiana Current as it approaches the West Indian region, and
the South Equatorial Current, which is known as the Brazil Current
when it turns to the south of Cape San Roque. This distinction is
accepted in this work, and reasons are adduced in Note 18 of the
Appendix in support of the view that the differentiation already
exists in mid- Atlantic, the island of Ascension being situated within
the northern or main stream and that of St. Helena within the
southern stream. Thus regarded, the Main Equatorial courses
westward from the Gulf of Guinea between the parallels of 2° N. and
10° S., whilst the South Equatorial flows west in the Central Atlantic
between the parallels of 10° and 20° S.

Though these currents are contiguous in mid-ocean, they have
different origins and, of course, different destinations. The Main
Equatorial in its birthplace in the Gulf of Guinea is fed by the
Guinea Current on its north side, and on its south side by the inshore
waters of the South African Current. It proceeds north of Cape
St. Roque to the West Indies, following the trend of the coasts of
North Brazil, the Guianas and Eastern Venezuela, and gathering
drift on its way not only from those shores, but from the Amazon,
the rivers of the Guianas, and the Orinoco. On the other hand, the
South Equatorial Current may be regarded as fed by the off-shore
or outside waters of the South African Current, and probably carries
less African drift. As it crosses the Atlantic it includes St. Helena,
but not Ascension, within its zone. It is then deflected south of
Cape St. Roque and flows down the coast of Brazil, finally gathering
the drift of the Rio de la Plata. Then, blending with the South
Atlantic Connecting Current, its waters make the return journey past
Tristan da Cunha to the South-west African coasts. It should,
however, be noted that some of the waters of the Brazil Current
probably flow southward to unite with those of the West Wind
Drift Current, the easterly surface-current of the "Roaring Forties."
In this manner South American drift would be carried eastward
towards Australia.

The Transport of Bottle-drift in the Main Equatorial
Current. — Having thus described the view of the current system in
the South Atlantic which is adopted in these pages, I will proceed to
deal with the indications of the bottle-drift in the case of the Main
Equatorial Current. Generally speaking, whilst the mass of this
bottle-drift of the North Equatorial Current strikes the West Indies
to the north of Barbados and St. Vincent, most of the drift of the
Main Equatorial Current enters the West Indian region to the south
of those islands. Many of the bottles brought by the southern
current — about 30 per cent. — are stranded on the coasts of Trinidad
and Tobago and on the Venezuelan shores of the Gulf of Paria.
The others are either thrown up on the isles of the Lesser Antilles,
mainly in the south, or pass between them into the Caribbean Sea,
where they mingle with the bottle-drift of the North Equatorial

CURRENTS OF THE ATLANTIC 61

Current, and are subsequently dispersed over the shores of the
Caribbean Sea and of the Gulf of Mexico, reaching in some cases the
coasts of Florida.

As indicated by the data at my disposal, the general distribution
of the bottle-drift of the Main Equatorial Current in the tropics of
the New World is as follows —

Places of Recovery of Sixty Bottles cast Overboard in
THE Main Equatorial Current between the Coast of
North Brazil and the Vicinity of St. Paul's Rocks

(The data are obtained from Schott's memoir in three-fourths of the cases and from
the American charts for the rest)

The Guianas . . . . . .5 per cent.

Trinidad mainly, but including also Tobago

and the neighbouring coast of Venezuela .31
The Lesser Antilles (chiefly in the southern

islands) 26 „

The Greater Antilles (south coasts of Hispaniola,

Cuba, and Jamaica, including the off-lying

Cayman Islands . . . . .13

The Bahamas 2 „

The coasts of Central America (Nicaragua and

Honduras) . . . . . . 7 „

The Gulf of Mexico (chiefly on the western

shores) . . . . . . . 11 „

The coasts of Florida . . . . . 5 „

100

The convergence of the drift towards the limited region comprised
by Trinidad and its vicinity is conspicuous. But the materials
stranded in this locality are probably equalled in amount by those
that are carried swiftly past this region into the Caribbean Sea
through the Trinidad and Grenada passage to be thrown up ulti-
mately on the south coasts of Hispaniola, Cuba and Jamaica, on the
shores of Nicaragua and Honduras, on the western borders of the
Gulf of Mexico, and on the coasts of the Florida seas. If we separate
the bottles at their starting-place into two groups, those belonging
to the St. Paul's Rocks area and those nearer the coast of North
Brazil, we find that the concentration on Trinidad and its vicinity
is least marked in the case of the bottles approaching from the
vicinity of St. Paul's Rocks, the proportion reaching Trinidad from
this region of the Atlantic being only about 20 per cent., as compared
with nearly 40 per cent, in the case of those carried past the shores
of North Brazil.

But although the great mass of the stream of the Main Equatorial
Current passes into the Caribbean Sea, there is a subsidiary branch
which, after skirting the eastern and northern side of the Lesser
Antilles, unites with the North Equatorial Current and ultimately

62 PLANTS, SEEDS, AND CURRENTS

reaches the Bahamas, the north coasts of the Greater Antilles, the
Florida Strait and the Bermudas. This is the so-called " Antillean
Stream " to which Dr. Schott particularly refers (p. 13). About
6 per cent, of the bottles dealt with in the above tabulated results
represent the part played by this subsidiary current in distributing
the drift brought by the Main Equatorial Stream to the West Indian
region. They are those that are stranded on the northernmost islands
of the Lesser Antilles, on the north coasts of Porto Rico and Hispa-
niola, and on the off-lying Bahamas. An interesting example is
afforded in the case of bottle No. 363 in Schott's memoir (p. 13 and
map ii.). It was dropped into the sea about half-way between Cape
St. Roque and St. Paul's Rocks, and was recovered on Rum Cay in
the Bahamas five and a half months afterwards, having accomplished
the passage of 3078 miles at a minimum daily rate of 18*2 miles.
Another interesting illustration is afforded by a bottle which, after
being thrown over about 200 miles off the mouths of the Amazon in
2° 36' N. and 47° 6' W., was picked up near St. Thomas in 18° 27' N.
and 64° 49' W. twenty-eight days afterwards, having been carried
1400 miles at a minimum rate of fifty miles a day (U.S. Chart, North
Atlantic, May 1909, No. 80). The mingling of the drift of the
North and Main Equatorial Currents in the region between the
Bahamas and the Greater Antilles is a point of great interest in the
distribution of seeds by currents.

The South Equatorial and the Brazil Currents. — Being, as
I have shown above, the continuation of the South Equatorial
Current that crosses the South Atlantic about the latitude of St.
Helena, the Brazil Current proceeds southward, following the trend
of the coast, part of its waters reaching the estuary of La Plata, the
greater portion, however, being deflected eastward between the 30th
and 35th parallels, where they join the South Atlantic Connecting
Current that runs eastward to the South African coast. In this way
it is possible for drift to make a complete circuit of the South Atlantic,
since on approaching the South African coast the materials not
stranded would be borne northward in the South African Current,
those in the inshore waters ultimately getting into the Main Equa-
torial Current, and those in the off-shore waters coming within the
influence of the South Equatorial Current. The bottle-drift data at
my disposal for this ocean are scanty, but they illustrate the circular
play of the currents, and they show that whilst extra-tropical South
Africa may supply drift to tropical Brazil, it may receive drift from
the same region. One of the most interesting records of bottle-drift
ever published in this connection is concerned with a bottle that was
thrown into the Indian Ocean off the coast of Natal and was recovered
on the shores of Brazil in lat. 17° 30' S. The bottle just mentioned
must have doubled the Cape, and in its subsequent transport by the
South African and South Equatorial Currents we have an illustration
of the passage of drift from extra-tropical South Africa to tropical
Brazil (further details of this remarkable drift are given a page or
two later).

But to understand how tropical Brazil may in its turn supply
drift to South Africa it will be necessary to examine the working of

CURRENTS OF THE ATLANTIC 63

the Brazilian Current, as exemplified by bottle-drift in the fourth
map and on p. 20 of Schott's memoir. It is not a rapid stream,
its rate being twelve to twenty miles a day, and in consequence it
is liable to a set-back within the tropics during the southern winter
owing to the influence of the prevailing South-east Trade. In this
manner, no doubt, some of its drift is carried back round Cape
St. Roque and mingles with that of the Main Equatorial, an event
which actually occurred in the case of some bottles referred to in
this memoir. But for this occasional set-back, the current would
have a steady flow south. Yet the bottle-drift dealt with by Dr.
Schott in this connection only tells part of the story. Though
many bottles are cast up on the coasts as far south as Montevideo,
we know nothing of those that must have been deflected eastward to
be carried across in the South Atlantic Connecting Current to the
west coasts of South Africa, where in the great majority of cases
they could never be recovered. Their track across the Atlantic
would curve south to about the 40th parallel, and would then be
represented by that laid down by Dr. Schott in his map for a bottle
which, after being cast over in about 41° 30' S. and long. 32° W.,
was recovered near the Cape of Good Hope.

The Current-connections of the South Atlantic with the
Indian and Pacific Oceans, as Illustrated by Bottle-drift. — •
This is a matter of importance, since upon it depends the possibihty
of the intrusion of seed-drift into the South Atlantic from the oceans
on either side of it. Taking, first, the connection with the Indian
Ocean, Dr. Schott gives the tracks of two bottles that doubled the
Capes of Agulhas and Good Hope in their passage westward into the
South Atlantic. One of them, after being dropped overboard less
than a hundred miles south of Port Elizabeth, was cast up on the
west coast of Cape Colony in about lat. 33° S. (maps 4 and 5). The
other accomplished a much longer passage. Having been thrown
into the sea off the coast of Natal in lat. 29° 24' S. and long. 33° E.,
it was carried by the Agulhas Current round the southern extreme of
the continent, whence it passed into the South African Current and
from there into the South Equatorial Current, being ultimately
stranded on the coast of Brazil in lat. 17° 30' S. This involved a
drift of about 4120 miles, a period of 612 days elapsing between the
start and the recovery of the bottle (pp. 19, 27 ; maps iv. and v. ;
track 6).

With regard to the connection between the South Pacific and
South Atlantic Oceans round the Horn, the data at my disposal
indicate that it occasionally occurs. Most of the bottles dropped off
Cape Horn are drifted before the Westerly Winds to Australia — as
illustrated by the tracks of four bottles mentioned by Schott and
others which are specially dealt with in Chapter XIII. In the same
chapter allusion is made to the figurehead of a ship burnt at sea in
these latitudes which was also recovered in Australia. In none of
these cases did the drifting object double the Horn; but Schott
gives the track of a bottle in map vi. which was cast over in about
lat. 54° 20' S., less than a hundred miles off the west coast of Tierra
del Fuego, and drifted in the Cape Horn Current to the Falkland

64 PLANTS, SEEDS, AND CURRENTS

Islands. Had the bottle missed these islands, it would have been
borne north-east in the same current, and, getting within the influence
of the Brazilian Current, as it is deflected eastward, would have
entered the circulation of the South Atlantic.

The Difficulties Connected with the Drifting Rates of
Bottles across the Atlantic. — We come now to the discussion of
the time occupied by the drifting bottles in crossing the Atlantic,
either from the American or from the European and African side of
the ocean. In the charts the average drift per day is calculated up
to the date of the recovery of the bottle. This, as is pointed out by
the compiler of the American charts, must be in most cases less than
the actual drift-rate, since no allowance is made for the time,
probably often considerable, during which the bottle lay undisturbed
on the beach." So also Schott observes (p. 10) that the calculated
velocities are merely minimum values, which could only in the rarest
cases correspond approximately to the true rate. This naturally
introduces an element of great uncertainty; but, if we assume that
20 or 25 per cent, of the bottles were recovered without great delay,
it is likely that we shall obtain an approach to the average drift-rate.
The results here employed have been calculated on this basis. As
before observed, the Prince of Monaco adopted a similar method in
estimating the mean velocity of his floats, usually taking the average
of the fastest fourth or third, except when the data were few, when
he selected the most rapid example.

After handling the data during a long period it is not difficult to
recognise sets of results which possess a critical value. One of these
is given below in connection with five bottles dropped at the same
date into the sea in the vicinity of Cape Hatteras. Here it is not
hard to distinguish between the bottles that were quickly recovered
and those that had been lying a long time on the shore. It rarely
happens that we can exclude the element of uncertainty altogether.
But it is manifest, when the bottle is picked up afloat off a coast by
fishermen, or when the finder remarks that as it lay on the sand it
had all the appearance of having been washed up by the last tide,
that we are on relatively safe ground. Instances of both these
occurrences are mentioned in the following pages. As an example
of the great range of the periods elapsing between the start and the
recovery of the bottles I will cite the case of nine bottles which
crossed the Atlantic from the Florida region to the coasts of Europe.
Since the periods varied between eleven months and three years, it
is obvious that a year and more may be spent by a stranded bottle
before it is found. However, in the case of some of these belated
" finds " one may suspect that there has been a long sojourn in the
still waters of the Sargasso Sea, the notable gathering-place of the
wreckage of the North Atlantic. As in the instance of some bottles
cast up on the Azores, where an interval of several years elapsed,
one may seek here for an explanation of the great delay in the re-
covery. Such a case as is mentioned by Purdy in the Columbian
Navigator for 1839, where a bottle dropped overboard off Madeira in
June 1825 was picked up ten years after on the Turks Islands, may
be placed in this category. The table subjoined is intended to illus-

CURRENTS OF THE ATLANTIC 65

trate the critical value of the data supphed by a number of bottles
cast into the sea at the same place and at the same time.

Five Bottles put Overboard together from the s.s. "Cherokee" about a

HUKDRED MILES TO THE NORTH OF CaPE HaTTERAS ON DECEMBER 21, 1905

(Results taken from the North Atlantic Pilot Chart for December 1908, published
by the U.S. Hydrographic Office.)

Place of Recovery

Interval in Days

Total Drift in
Nautical Miles

Average Drift in
Miles per Day

103

520

50

168

520

31

West coast of Scotland

(56°30'N.) . . . .

390

3040

7-8

Shetland Islands

466

3210

6-9

Norway, near the North

Cape in lat. 70° 20' N.,

long. 22° 58' E. . . .

416

4250

10-2

Here it is evident that the three bottles with the longest drifts
followed the same track until near the Scottish coast, and that the
one recovered in the north of Norway must have been found soon
after it had been stranded.

The Drifting Rates of Bottles across the Atlantic. — In the
following table (p. 66) I have elaborated most of the data at my dis-
posal that concern the drifting rates of bottles across the North and
the Equatorial Atlantic. The subsequent remarks relate to the
different passages, beginning with the traverse from the Florida
Strait and the neighbouring West Indian waters to the coasts of
Europe. These are the most interesting of the bottle-drift records,
since Europe is here brought into touch with a locality that not only
receives drift from the entire West Indian region, but is also the
recipient of drift transported by the North and Main Equatorial
Currents from tropical Africa, as well as from the coasts of the
Guianas and North Brazil. The traverse of the ocean from the
European and African side to the New World is then dealt with, and
the discussion ends with some general conclusions relating to the
average periods taken by bottle-drift in performing the various
passages and traverses of this ocean.

The Drift-rates from the West Indies to the Coasts of
Europe. — The stages in this traverse of the North Atlantic are indi-
cated in the table given on p. 66, and it has already been established
in a previous table that quite four-fifths of the bottles are stranded
on the Scottish, Irish, English and French coasts. Whilst the
shortest passage was performed in about eleven months, the average
period was about fourteen months. The quickest drift was that of
a bottle which reached the Irish coast from off the north coast of
Hispaniola in 337 days, a passage of 4140 miles (U.S. Pilot Chart,
N. Atlantic, May 1909). It seems unlikely that the traverse from
off Cape Hatteras could be often accomplished by a bottle in less
F

66 PLANTS, SEEDS, AND CURRENTS

^"2

Q ^

o

OS

2 -Sw

5i,

O g

o a
M a

nJ 5. OS

n3 c o w

!-J 00 -is o* §>

S K O

•4-1 o S e

•C ^ O o

• w w

O V O V o

-a ^ ^ 5s B
p ^ ^ -H 5

45

o

2S

= .2

O 6C

Q I

o

'o

05
CO

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MS..

C CO

II

So -13

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a t3

CD IS

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l-H o

-ts •+-!

S3 O 73
O . C

P4 05

b P

2 SO

O

CURRENTS OF THE ATLANTIC

67

1

1

I

See Note 18 of I
Appendix

1

1

1

1

1

Partly estimated

Partly estimated

8-8; 8-7 j

o

<M

16-8; 120: 11-2;
10-6

1

20-0; 19-8

34-2; 28-1; 27-2

19-8

50-0; 43-5; 36-2;
34-2

16-8

1

1

db

12-8

12-6

20-0

20-0

30-0

20-0

40-0

17-0

o

o
CO

o

CO

<N
O

CO

o

<M

CO

o

§

o
o

o

§

00

oo

CO

00

3500

2600

1300

3200

2000

2000

1000

1000

3200

2S00

4000

cc

(M
(M

ce

o

1

1

Vicinity of Madeira and the
Canary Islands

^ a

o o

About half-way between the
Cape Verde Islands and the
West Indies, 13°-19° N. lat.

Vicinity of Ascension Island

Vicinity of St. Paul's Rocks
(0°-7° N. lat.; 22°-32° W.
long.)

Between St. Paul's Rocks
and Cape St. Roque

About half-way between St.
Paul's Rocks and Trinidad

0£E the Amazon estuary

Off the Amazon estuary

Gulf of Guinea

Gulf of Guinea

in the North Equatorial
Current between 10° and
20° N. lat.

To the West Indies in
the direction of Trinidad
in the Main Equatorial
Current

To the coast of Florida
by the Caribbean Sea and
Gulf of Mexico

To the vicinity of Cape
St. Roque in mid-stream

To the West Indies
(Trinidad)

68 PLANTS, SEEDS, AND CURRENTS

than a year, though the shortest period would be rather over ten
months. In Note 16 of the Appendix reference is made to a dereUct
which drifted from Baltimore Bay to the Hebrides in a little over
ten months, but about half the time was spent drifting about within
a small area in mid-ocean. A critical value belongs to a rate of
eight miles which is given by Schott (p. 11, map ii.) for a bottle that,
after bcx^.g thrown into the sea about 350 miles north-east of Cape
Race, was recovered on the Isle of Skye. According to the finder, it
appeared to have been thrown up at the last flood-tide.

The uniformity in the average daily rate of eight to nine miles across
the North Atlantic is remarkable, and this brings us to record that
the average rates computed by the Prince of Monaco for his floats
in the eastern half of this ocean are only half this amount. His
observations, as we have seen, were made on a line drawn from the
Azores to the Banks of Newfoundland, as well as in localities to
the east and north of that line ; and he places the average drifting
rate to the shores of Europe, ranging from Norway to Portugal,
at four to five miles a day. This discrepancy, however, is capable
of explanation, and I imagine that it may be largely discounted.
It is evident that the Prince of Monaco mainly based his rates on
the experiments made between June and July 1887, between New-
foundland and the Azores and to the north of that group. On the
other hand, the data tabulated above for this traverse are supplied
by records that cover a long period of years, and in this manner the
disturbing influences retarding the eastward flow of the surface-
currents during a particular year or season have been eliminated.
To such retarding influences experiments made in the same season
might be exposed. It is noteworthy that in the experiments of the
Prince of Monaco in 1886, when the floats were cast overboard at
distances ranging from 400 to 700 miles from the Portuguese and
French coasts, more rapid velocities were obtained. The five fastest
rates of eleven bottles stranded on the coasts of Portugal and West
Spain gave a mean of 7*15 miles a day. So, again, the mean of the
seven quickest rates for twenty-four bottles recovered on the west
coast of France was 6 67 miles a day. The Prince of Monaco's floats
were as a rule deeply submerged, and were thus much less likely to
be influenced directly by the wind than the ordinary floating bottle.
Yet the retarding effect of contrary winds might be counterbalanced
by the acceleration produced by fair winds.

The Drifting Rates from off the Coasts of Europe to the
West Indies. — In making this traverse bottle-drift seems to travel
at about the same average speed as in the case of that brought to
Europe in the Gulf Stream — namely, eight to nine miles a day, the
time occupied being usually sixteen to seventeen months. But the
rate varies greatly in different portions of the traverse. It is in the
passage south from European latitudes to the region of the North
Equatorial Current that the slowest progress is made. From the
data supplied by a number of bottle-drifts in the American charts
it is evident that the average daily rate for this passage is only
four or five miles. On the other hand, as shown in the table, bottles
starting from the vicinity of the Canary Islands are carried into the

CURRENTS OF THE ATLANTIC 69

North Equatorial Current, and accomplish the traverse to the West
Indies at an average rate of nearly nine miles a day ; whilst farther
south, in the latitude of the Cape Verde Group, the trans-oceanic
passage is performed at an average speed of nearly thirteen miles
a day. These conclusions are confirmed by the results of the Prince
of Monaco's experiments in 1886 opposite the coasts of France and
Portugal along the meridian of 17° 40' W. From this region the
daily drifting rate to the Canary Islands is placed at four and a half
miles and to the West Indies at ten and a half miles. Daussy, whose
paper on bottle-drift in this ocean (Comptes Rendus, 1839, p. 81)
has before been mentioned, places the daily speed of bottles in the
equatorial zone of the North Atlantic at eight to ten miles.

An interesting case is recorded in the table of a bottle which
accomplished the whole of the passage from a point about 260 miles
off the south-west of Ireland to the south-eastern extremity of the
Bahamas in a minimum time of 597 days (U.S. chart, December

1908, bot. 85). The greatest velocity referred to in the table in
connection with the passage in the North Equatorial Current was
attained by a bottle that travelled from mid- Atlantic to the West
Indian region at an average speed of 16-8 miles a day. It per-
formed the passage from 9° 51' N. lat. and 32° W. long, to St. Vincent,
a distance of 1660 miles, within ninety-nine days (U.S. chart, February

1909, bot. 48). It is worth noting that the derelict American schooner
Alma Cummings was drifted at the rate of sixteen miles a day from
a position 600-700 miles west of the Cape Verde Islands to the Panama
Isthmus (see Note 15 of Appendix). A critical value attaches itself
to a bottle that was transported in the North Equatorial Current
from a position south of Cape Verde Group (lat. 14° 1' N. ; long.
25° 2' W.) to the Grenadines in 169 days, which gives a daily rate
of about thirteen miles. There could have been but little loss of
time in its recovery, since it was found afloat off the coast (see
Nautical Magazine for 1852, bot. 42, and 1853, p. 437).

The individuality of the North Equatorial Current is not always
sufficiently recognised. It is something more than the North-east
Trade-drift. Between the parallels of 10° and 20° N. it is illus-
trated by about fifty bottle-tracks in Schott's maps and by nearly
half that number in the American charts examined, as well as by
about a dozen other examples from other sources. The part that
it takes in the circulatory movement of the waters of the north
Atlantic is strikingly exemplified in the results of the Prince of
Monaco's experiments in the temperate latitudes of the north-east
Atlantic, almost a tenth of the floats recovered having been found
in the West Indian region. All the months of the year are repre-
sented in the records at my disposal, and there is not a single instance
of a drift to the eastward in these latitudes (10°-20° N.) in the open
ocean. Always there is a steady flow to the west, with but little
of the " southing " one would expect in a mere trade- wind current.

Drift-Rates from Tropical Africa to Brazil and the West
Indian Region in the Main Equatorial Current. — A much
greater velocity is regularly displayed by the Main Equatorial
Current as it traverses the Atlantic from the Gulf of Guinea to the

70 PLANTS, SEEDS, AND CURRENTS

coasts of North Brazil, thence proceeding northward past the Guianas
to the West Indies. From the Admiralty Sailing Directions , Laugh-
ton's Physical Geography, and other works of reference, it is evident
that very high velocities, even of sixty miles a day, are at times
attained by this current on its way to Cape St. Roque. It is prob-
able, however, that an average rate of twenty to thirty miles is near
the truth. In the latter part of its course, along the coasts of North
Brazil and the Guianas, it nearly doubles its speed, flowing usually
from thirty to fifty miles a day and occasionally as much as seventy
or eighty miles.

The behaviour of the drifting bottle is quite in agreement with the
known great speed of this powerful current. In Note 1 of the
Appendix the data are discussed; and it is shown that whilst in
the slacker water in the vicinity of St. Paul's Rocks and Ascension,
that is, in the northern and southern portions of the current, the
bottles are carried along at a rate of about twenty miles a day, in
the centre of the stream, as it concentrates between St. Paul's Rocks
and Cape St. Roque, an average speed of thirty miles is attained.
From what has been said it would be expected that during the
remainder of the passage along the South American seaboard to
the West Indian region the speed of bottle-drift would respond to the
increase in the velocity of the current as it sweeps past the coasts
of North Brazil and the Guianas. This expectation is fully justified
in the facts given in the note, where a daily rate of between thirty
and fifty miles, and averaging forty miles, is indicated. It may be
inferred from these data that, starting from the Gulf of Guinea, a
bottle would require an average period of twelve weeks to reach
the vicinity of Cape St. Roque and of seventeen weeks to reach
Trinidad. It is, however, not improbable when the current runs
with unusually great speed that the traverse to the Brazilian coast
may be performed in as little as two months.

The Drifting Rate of Bottles from off the Amazon Estuary
TO THE Coast of Florida. — This establishes an interesting connec-
tion, since we already know how long a period is usually required
by bottle-drift for the passage from Florida to the shores of Europe,
namely, fourteen months; and we shall thus be able to determine
the time that would be required for Amazon drift, as typified by the
floating bottle, to reach our coasts. As previously remarked, the
track assigned in both the American and German charts to bottles
that arrive in the Florida seas from latitudes in the tropical Atlantic
south of 10° N. lies across the Caribbean Sea and through the Straits
of Yucatan. The data for three bottles that accomplished this
passage from off the Amazon to Florida waters are supplied in
Note 1 of the Appendix. It is there inferred that this traverse
of 3200 miles would be performed in about six months at the rate
of seventeen miles a day, from which it may be concluded that as
a rule the passage of Amazon drift to Europe would occupy twenty
months.

The Drift-Rates in the Brazil Current. — The Brazil Current
has been before alluded to as an extension of the South Equatorial
Current. Its velocity is usually stated to be from twelve to twenty

CURRENTS OF THE ATLANTIC 71

miles a day, which is greater than that displayed by numerous
bottle-drifts given by Schott, who says that more than ten miles a
day was seldom indicated (pp. 19, 20, map iv.). The longest passage
was that of a bottle which was carried about 1600 miles from opposite
Bahia to the vicinity of Montevideo at a minimum daily rate of
about ten miles. Many of the bottles, however, were stranded on
the coasts further north.

General Results of the Bottle-Drift Data for the Atlantic

AND THEIR APPLICATION TO THE DiSPERSAL OF SeEDS BY CURRENTS.—

In order to draw from the foregoing discussion some conclusions that
may be of practical value in the consideration of the dispersal of
seeds by currents in the Atlantic, I have given below a few general
results relating to the average periods taken by bottle-drift in accom-
plishing the various traverses and passages of this ocean.

Rbsults for the Times occupied by thb Drifting Bottle in crossing
THE Atlantic in Northern and Equatorial Latitudes

(A) From the Florida and neighbouring West Indian

region to the shores of Europe by the Gulf
Stream route.

(B) From off the coasts of Europe to the West

Indies (Lesser Antilles and the Southern
Bahamas) by the Canary and Cape Verde
groups and in the North Equatorial Current.

(C) From the Gulf of Guinea to the West Indies

(South of Barbados) in the Main Equatorial
Current.

(D) From the Gulf of Guinea to the nearest coast

of Brazil in the Main Equatorial Current.

(E) From off the Amazon estuary to Florida by

the Caribbean Sea and the Straits of Yucatan
in the Main Equatorial Current.

(F) From off the Amazon estuary to the shores of

Europe by the Caribbean Sea, the Yucatan
and Florida Straits, and the Gulf Stream
route.

(G) The circuit of the North Atlantic from the

Florida region to the Lesser Antilles and the
Southern Bahamas by the Gulf Stream route
and in the North Equatorial Current. (For
the return to the Florida seas 160 days should
be added for the usual completion of the
route by the Caribbean Sea and the Gulf of
Mexico, and 100 days for its completion by
the short passage through the Northern
Bahamas.)

4000 miles at 9-2 miles a day
in 435 days, or about a
year and two months.

4500 miles at 9 miles a day
in 600 days, or a year and
4| months.

4000 miles at 34 miles a day
in 118 days, or i.*^out 4
months.

2500 miles at 30 miles a day
in 83 days or 12 weeks, but
under exceptionally favour-
able conditions in 60 days.

3200 miles at 17 miles a day
in 188 days, or about 6
months.

7200 miles at 11| miles a day
in 623 days, or about 20
months. Calculated from
results A and E.

8500 miles at about 9 miles
a day in 935 days, or about
2^ years. Calculated from
results A and B.

The first matter in connection with these results that needs further
discussion is the time occupied in the circuit of the North Atlantic.

72 PLANTS, SEEDS, AND CURRENTS

For obvious reasons it would be very difficult to demonstrate this
circuit for any particular bottle. The nearest approach to the
complete record is that of the bottle, already alluded to, which was
picked up on the west coast of Ireland thirty-four months after it
had been cast over to the westward of the Cape Verde Islands. It
is easy to construct the circuit piecemeal fashion. A striking instance
is afforded by two bottles which in one case reached the South-
eastern Bahamas from off the coast of Ireland, and in the other
reached the Irish coast from the South-eastern Bahamas, the track
of the North Equatorial Current being followed in the first case
and the Gulf Stream route in the second case. The data for these
observations are given in Note 20 of the Appendix ; but it may here
be stated that the total period, calculated up to the dates of the
recoveries, amounts to 934 days, and the average drifting rate to
nearly ten miles a day. This period is identical with that given
under G in the above table, though to that period about a hundred
days should be added for the passage from the South-eastern Bahamas
to the Florida seas. . . . Derelicts would probably perform the
circuit of the North Atlantic in a shorter time. Whilst the circuit,
beginning and ending with the Florida seas, would require about
three years for a bottle, it might not require more than two years
for a derelict. The Alma Cummings, when drifting in 553 days from
off Cape Hatteras to the Panama Isthmus, nearly described the
circle; but since the wreck was deflected south to the westward of
the Azores, its passage was somewhat shortened (see Note 15).

The Distribution in the West Indian Region of Seed-drift
Brought by the North and Main Equatorial Currents as
ILLUSTRATED BY BoTTLE-DRiFT. — By following the indications sup-
plied by the floating bottle in this matter we shall be determining
the distribution over the West Indian region of the seed-drift brought
in the North and Main Equatorial Currents. Bottles arriving in
the first-named current strike the South-eastern Bahamas and the
Lesser Antilles, in the last locality usually north of Barbados. Of
those reaching the south-eastern islands of the Bahamas the great
majority are stranded in that neighbourhood; but a few, as is shown
in Note 13, are carried in the prevailing westerly drift-current to the
Florida seas. However, as is indicated in the table on p. 57, only
about 25 per cent, of the bottles brought to the West Indian region
in the North Equatorial Current are beached on the Bahamas.
About 10 per cent, are carried beyond that group and are thrown
up on the north coasts of the Greater Antilles. All the rest strike
the line of the Lesser Antilles, but generally north of Barbados,
and more than half of them are stranded on those islands. The
survivors (about 27 per cent, of the original total) pass between
the islands into the Caribbean Sea. Most of them are stranded on
the south coasts of the Greater Antilles and on the shores of Central
America ; but a few (amounting to about 7 per cent, of the original
total) are carried through the Straits of Yucatan into the Gulf of
Mexico and are ultimately beached on the shores of that gulf and
on the coasts of Florida. Several examples are given in the charts
of bottles that illustrate this circuitous route from the Lesser Antilles

CURRENTS OF THE ATLANTIC 73

across the Caribbean Sea and by the Gulf of Mexico to Florida.
The length of the passage is about 2000 miles, and the indications
are that about 160 days would be required for its accomplishment.

The distribution over the West Indian region of the seed-drift
brought by the Main Equatorial Current is well exemplified by the
disposal of its bottle-drift as described on p. 61. After depositing
5 per cent, of its burden on the shores of the Guianas, it leaves 31 per
cent, on Trinidad and Tobago and on the neighbouring Venezuelan
coasts, and 26 per cent, on the islands of the Lesser Antilles, chiefly
in the south, only 2 per cent, reaching the Bahamas. The remainder
(36 per cent, of the total) breaks through the islands and passes into
the Caribbean Sea, more than half being thrown up on the south
coasts of the Greater Antilles and on the shores of Central America,
whilst the survivors, after passing through the Straits of Yucatan,
are stranded on the shores of the Gulf of Mexico and on the Florida
coasts.

The mingling in the Caribbean Sea of drift brought by the North
and Main Equatorial Currents is well exemplified in the remarks
above made. Whether brought by the one current or by the other,
the drift, after it enters this sea, has the same distribution on the
south coasts of the Greater Antilles, on the shores of Central America
and of the Gulf of Mexico, and on the Florida coasts. But the
mingling of the drift begins off the Atlantic coasts of the Lesser
Antilles and in the southernmost of those islands. In the first case,
the Antillean Stream, referred to on a previous page, commences the
mixing process in its north-westerly course towards the Bahamas.
In the second case, although the island of Barbados usually divides
the main streams of the two equatorial currents, there is not infre-
quently an overlapping of the currents in its vicinity with, as the
result, an intermingling of their drift in the southern islands of the
Lesser Antilles.

The meeting in West Indian waters of seed-drift brought by these
two great equatorial currents from the North and South Atlantic
is a matter of great interest for the student of plant distribution.
It is a subject that attracted the attention of Dr. Schott when dis-
cussing the bottle-drift data of this region (p. 11). The importance
of this fact is obvious. Whilst the North Equatorial Current brings
to the West Indies the sweepings of the Atlantic seaboard of
North America, and of Southern Europe and North-west Africa,
through the respective agencies of the Gulf Stream and of the Portu-
guese or North African Current, the Main Equatorial Current carries
to the same region the sweepings of both sides of the South Atlantic,
from tropical West Africa, South-west Africa, Brazil, and the
Guianas.

The Burden of the Main Equatorial Current. — ^This current
bears westward not only drift from the shores and great rivers of
tropical Africa, but also drift which it has received from the South
African Current. This current has previously swept the shores of
South-west Africa, and has caught up drift brought across by the
South Atlantic Connecting Current from the Brazil Current on the
other side of the ocean, materials derived from the Rio de la Plata

74 PLANTS, SEEDS, AND CURRENTS

and from the shores and estuaries of Brazil south of Cape St. Roque.
The burden carried westward by the Main Equatorial Current must,
indeed, be a motley one. The seed-drift of the rivers of two conti-
nents, including some of the largest rivers of the world, contribute
to its freight. It bears westward towards Brazil drift of the Plate,
the Congo, and the Niger; and as it sweeps northward to the West
Indian region it gathers materials from the Amazon, the rivers of
the Guianas, and the Orinoco.

But the possible sources of seed-drift do not end here, since the
Main Equatorial Current may receive accessions from the Indian
and Pacific Oceans. The Atlantic is not a closed ocean to the south.
It has already been shown that bottle-drift from the east coast of
Africa can double the Cape and reach the shores of Brazil, and
that materials from the Pacific side of Fuegia can double the Horn
and reach the Falkland Islands. In the first case the Indian Ocean
is tapped as a source of seed-drift. In the second case we have
the possibility that the drift from New Zealand and the islands of
the Southern Ocean, after it strikes the coasts of South Chile and the
western shores of Fuegia, may at times double Cape Horn and get
within the influence of the currents of the South Atlantic. (The
bottle-drift of high southern latitudes is dealt with in Chapter XIII.)

The Island of Trinidad as a Centre of Drift Dispersal. —
Next to the Florida Sea, the gathering-place of much of the floating
seed-drift of the West Indian region before beginning its transatlantic
passage in the Gulf Stream, there is no locality so interesting as a
drift-centre as the island of Trinidad. From the standpoint of the
dispersal of plants by currents, it is the connecting centre or junction
of the lines of dispersal that converge from the Atlantic side and
diverge on the West Indian side. As shown by the floating bottles,
it is the Main Equatorial Current that principally piles up drift on
its beaches, drift from tropical West Africa and from the north-east
seaboard of South America, though at times, as indicated below,
drift also reaches it from the North Atlantic through the North
Equatorial Current. Whilst materials from the South American
mainland north of Cape St. Roque doubtless greatly predominate,
including, as they do, the drift of the Amazon, of the rivers of the
Guianas, and of the Orinoco, yet materials from the West African
rivers, the Niger and the Congo, as well as from the shores of the
Gulf of Guinea, must be represented.

The bottle-drift data relating to this locality are worthy of further
remark. It has already been shown that about thirty of every
hundred bottles recovered after being thrown into the Main Equatorial
Current between the coast of North Brazil and St. Paul's Rocks
reached Trinidad. Much of the Amazon drift, as observed below,
is cast up on the shores of this island. Five out of sixteen bottles,
that were recovered after being dropped overboard off the Amazon
estuary, were stranded on Trinidad. Dr. Schott (pp. 12, 14) dwells
on the very large number of records of drift bottles that were returned
to the " Deutsche Seewarte " in Hamburg from the east coast of
this island, almost all of them arriving there from the south-east
and east-south-east, less than 10 per cent, coming from the east or

CURRENTS OF THE ATLANTIC 75

north-east, or from latitudes north of 10° N. within the zone of the
North Equatorial Current. It may be, therefore, truly said that on
the beaches of Trinidad we find sampled all the seed-drift that reaches
the West Indian region, and, in fact, the New World.

The Transport of Amazon Drift to the West Indian and
Florida Regions and Probably also to Europe. — ^The transport
of Amazon drift to the West Indian Islands has long been surmised,
and in this connection we may quote the remark of Sir D. Morris
that the general characters of the drift on the south coast of Jamaica
point to a source in the Orinoco and the Amazon {Nature, January 31,
1889). The vegetable drift brought down in such quantities by the
Amazon soon gets into the rapid stream of the Main Equatorial
Current and is distributed over the West Indian region. " The
waters of the Amazon," writes Laughton in his Physical Geography
(1873, p. 188), " at first set to the north-east, but they soon incline
to the northward, and falling into the strength of the current are
swept away to the north-west." Bates observed Amazon drift,
more particularly the fruits of Manicaria saccifera, which are so
characteristic of West Indian beach-drift, about 400 miles to the
north of the mouth of the estuary {The Naturalist on the River Amazons y
1864, p. 461). The American and German bottle-drift charts clearly
indicate the mode of distribution of such floating fruits and seeds
and the tracks that would usually be followed. I here give the
places of recovery of sixteen bottles thrown into the sea between
200 and 400 miles north and east of the Amazon estuary, the data
being mainly supplied by the American charts. Three were cast
up on the coasts of the Guianas, five on Trinidad, one on the adjacent
island of Tobago, one on the neighbouring Venezuelan shores, three
on the Lesser Antilles (between Grenada and the Virgin Islands),
one on the shores of the Gulf of Honduras, and two on the east
coast of Florida after passing through the Florida Straits. One of
the records relating to the Florida coast should be specially men-
tioned here, since my authority is an old newspaper cutting dating
back, perhaps, to the closing years of last century. A bottle thrown
over from the Prince Eugene on March 11, about 300 miles north-east
of the Amazon estuary, was picked up 279 days afterwards on the
east coast of Florida, in lat. 27° 30' N. The captain was informed
by letter from the Hydrographic Office in Washington that it had
performed a passage of 3320 miles.

In establishing this link by bottle-drift between the estuary of
the Amazon and the Florida seas we indicate the probability of fruits
and seeds of the Amazon drift being transported to the shores of
Western Europe. It is in the neighbourhood of the Florida Straits
that West Indian drift gathers before starting northward on its
rapid journey through the straits towards Cape Hatteras and thence
across the Atlantic. The data enable us to place the period needed
for this long passage from the Amazon to Europe at about twenty
months, allowing six months for the first stage ending with the
Florida Straits, and fourteen months for the Atlantic traverse. It is
on the same grounds — namely, that drift from the Main Equatorial
Current reaches the Florida coasts and that drift from the Florida

7^ PLANTS, SEEDS, AND CURRENTS

Straits is stranded on the shores of Europe, that Dr. Schott (p. 13)
assumes the presence of water from the southern hemisphere in our
northern seas. It is true that no bottle from off the mouths of the
Amazon seems to have been found on the coast of Europe ; but we
have the record of a bottle, referred to on p. 59, that was dropped
into the Caribbean Sea about 100 miles from the south coast of
Jamaica in the direct track of the Main Equatorial Current and was
recovered on the Irish coast. The first part of the passage from the
coast of Brazil would be indicated by the track of a bottle that
reached the Cayman Islands from Ceara, north-west of Cape St.
Roque (Savage English, Kew Bull, 1913, p. 370).

But the demonstration of this link between the Florida Straits
and the Amazon estuary may mean even more, since the Main
Equatorial Current before quitting the Gulf of Guinea would have
gathered drift from the West African coasts and from the estuaries
of the Niger and the Congo. It is therefore not unlikely that even
West African drift might find its way by this circuitous route to the
shores of Europe. The bottle-drift data indicate that if Amazon
drift can reach European waters in twenty months that from the
Congo would require two years. Reference has several times been
made to a bottle which was found on the Irish coast thirty-four
months after it had been thrown over to the westward of the Cape
Verde Islands, having crossed and recrossed the Atlantic in the
North Equatorial Current and in the Gulf Stream. But I possess
no bottle-drift data bearing directly on the possibility of drift being
carried from the Gulf of Guinea and the two great rivers of equatorial
West Africa to the coasts of Europe. There is, however, the ex-
tremely interesting observation of General Sabine, where casks of
palm oil from a ship wrecked on the borders of this gulf are stated
to have been drifted ashore in the following year at the extreme
north of Norway, and there is the case of a bottle thrown over from
the Lady Montague, two and a half leagues north-east of Ascension,
which was found afloat off the coast of Guernsey 295 days afterwards.
There are, however, serious difficulties connected with the first case,
and as regards the second it seems incredible that a bottle could
twice traverse the Atlantic, in equatorial and north temperate lati-
tudes, in less than ten months. Both of these exceptional cases
are dealt with in Notes 25 and 26 of the Appendix.

The Balance of the Account between the Old and the
New World. — It is an error to place an equal value, as De Candolle
does in his Geographie Botanique (pp. 763-4, 1855), on the work of
the Gulf Stream and of the Equatorial Currents in transporting
seeds to the Old World and in carrying them to the New World in
a suitable condition for germination. He considers that the seed-
drift would be carried to the Gulf of Guinea from the tropics of the
New World in that portion of the Gulf Stream that bends south
past Europe and North Africa to the Canary Islands. There is no
support given to this view by the numerous bottle-drift data at my
disposal. All such drift, when it approaches the vicinity of the
Cape Verde Group, is deflected westward and is borne in the North
Equatorial Current to the West Indies. There is no approach to

CURRENTS OF THE ATLANTIC

77

an equal value in the reciprocal exchange of seed-drift between the
tropical regions on the opposite sides of the Atlantic. When we come
to balance the account respecting the interchange of seed-drift
between the Old and the New World, we learn that in the " give-
and-take " process the gift from the New to the Old World would be
slight. All the seeds borne to Europe in the Gulf Stream from the
West Indian region would find uncongenial climatic conditions that
would deprive the gift of any value. But better prospects would
await those that chanced to be diverted south, either in the vicinity
of the Azores, or further east in approaching European waters,
where they would come within the influence of the Portuguese or
North African Current. In both events they might possibly be
stranded on the coasts of tropical Africa to the north of the Cape
Verde Islands; but, as indicated by the bottle-drift, the chances
are that they would not be stranded at all, but would be carried
back to the West Indies in the stream of the North Equatorial
Current.

It is also highly probable that seed-drift from the Atlantic shores
of North America, from Cape Hatteras northward, might be at times
transported to the shores of Europe in the Gulf Stream drift, as is
indicated in the tabulated results for bottle-drift before given.
Such dispersal would be effective for the seeds of a few coast plants
of temperate latitudes; but the seed-drift derived by currents from
such regions is always small in amount and frequently ineffective
for purposes of reproducing the plant. In my book on Plant Dispersal
(pp. 429, 434, 438) it is shown that dispersal by currents is mainly
restricted to warm latitudes. Whilst in the tropics seed-drift is
abundant on the beaches, in the cooler regions of the globe it is
usually very scanty and often masked by other vegetable debris.

Another possible way by which the New World might occasionally
present seed-drift to the Old World is afforded by the already
mentioned westward extension of the Guinea Current at certain
seasons of the year so as to constitute a counter equatorial current
(see Note 19 of the Appendix). Acting as a " backwater " to the
North and Main Equatorial Currents, it would be most effective in
returning African seed-drift to Africa ; but at times, by extending
nearer than usual to the New World, it might pick up a little drift
from the north-east coasts of South America. Then again, as
before suggested, it is probable that some of the drift gathered by
the Brazil Current from the shores and estuaries of Brazil south of
Cape St. Roque, as well as from the Rio de la Plata, might ultimately
find its way by the South Atlantic Connecting Current into the South
African Current and then into the Main Equatorial Current in the
Gulf of Guinea. But whether it would be beached on the South
African side seems imlikely, though there is an example of bottle-
drift which might be instanced in this connection (p. 63).

In the above discussion I have made the most of the possible and
probable chances of the communication of seed-drift from the New
to the Old World. The gifts at most would be unimportant and
casual, and when effective of a belated kind. Not for a moment
could a comparison be made with the large amount of effective

78 PLANTS, SEEDS, AND CURRENTS

seed-drift that must be rushed in a few months across the tropical
Atlantic in the streams of the North and the Main Equatorial Currents.
It is, as we have seen, only in the tropics that currents play an
important part in plant distribution. For ages these two currents
have been bearing their burdens westward direct from the African
shores. Except for the occasional intervention of a counter-equatorial
stream, as before described, there would be no direct return route
from the American shores.

Drift carried by Currents round Cape Horn, Cape Agulhas,
AND THE North Cape. — It is noteworthy that drift has been known
to double all the three great headlands which form the extremes of
the continents of South America, Africa and Europe, towards the
poles. Reference has already been made to this matter in different
connections. Thus on p. 63 it is shown that bottles can be carried
from off the coast of Natal round Cape Agulhas and across the
South Atlantic to tropical Brazil, and from the Pacific side of Tierra
del Fuego to the Falkland Islands. In neither case would the con-
nection appear to be a frequent one; but the transference of seed-
drift from the Indian Ocean to the South Atlantic would probably
be the most effective. With regard to the doubling of the North
Cape it is well known that West Indian seed-drift is carried by the
Gulf Stream to the vicinity of this headland, and in Chapter II. it
is pointed out that it may even double this promontory and reach
the shores of the White Sea. I have no example of this having been
accomplished by bottle-drift ; but that bottles can reach the vicinity
of this cape from the other side of the Atlantic is shown in the U.S.
Pilot Chart for December 1908, in the case of one dropped overboard
off Cape Hatteras.

Summary

1. As indicative of the track followed by the drifting seed and of
the time occupied in the traverse of the Atlantic the behaviour of
the drifting bottle affords very important data (p. 46).

2. After dealing with the sources of the materials employed, the
value of bottle-drift for the study of the dispersal of seeds by currents
is discussed. The small proportion of recoveries is pointed out
(p. 48), and it is shown that the difficulties connected with the
delays in the recovery are not so formidable as they at first seem
(p. 49). The water-logged derelict from off Cape Hatteras, the
baulk of mahogany from West Indian islands, the living turtle from
the warm latitudes of the New World, the floating bottle containing
the record of its start in Cuban waters or in Florida seas, the buoyant
seed that could have grown only in the West Indies or on the tropical
mainland of America, all tell the same story when they are stranded
on our European beaches (p. 48).

3. The treatment of the subject is divided into two parts : in the
first place, the tracks followed ; in the second place, the time occupied
by the drifting bottle; and in order to give method to the inquiry
the accomplishment of the circuit of the North Atlantic is first
dealt with. It is remarked that the circulatory movements of the
currents in this ocean are equally well illustrated, whether the

CURRENTS OF THE ATLANTIC 79

circuit is performed by one bottle or piecemeal by a number of
bottles (p. 51).

4. The traverse from the West Indies and from the south-east
coasts of North America to the shores of Europe in the Gulf Stream
drift is then considered. The fan-shaped distribution of bottle-
drift from the New World is then remarked, since it may be stranded
anywhere on the east side of the North Atlantic between the North
Cape of Norway and the coast of Morocco, reaching even the Canary
Islands. From the results of experiments covering a long period of
years it is inferred that drift may reach any given locality on the
European coasts from all latitudes on the American side of the North
Atlantic between the tropics and the sub-Arctic regions. Thus,
bottle-drift is stranded on the Irish coasts from all latitudes between
the Caribbean Sea and Davis Strait. The results of the extensive
researches conducted with specially devised floats by the Prince of
Monaco in the north-east Atlantic are here utilised (pp. 49-56).

5. Having shown that bottles are carried across the North Atlantic
to Europe from the West Indies in the Gulf Stream drift, the requisite
data are adduced to demonstrate that they can be returned from
European waters to the New World in the tropical latitudes of the
same ocean by the North Equatorial Current. The facts indicate
that from any locality in the Eastern Atlantic between the vicinity
of the Irish coast and that of the Cape Verde Group bottles can be
transported to any part of the West Indian region north of Barbados.
A few of them finally reach the east coast of Florida after traversing
the Lesser Antilles and crossing the Caribbean Sea and the Gulf of
Mexico. This track must have been followed by a bottle that, after
being cast over to the westward of the Cape Verde Islands, was
recovered thirty-four months later on the Irish coast (pp. 56-59).

6. After a short reference to the Guinea Current (p. 59), the
next point of importance touched upon is the passage of bottles
across the tropical Atlantic in the Main Equatorial Current from the
Gulf of Guinea to the coast of Brazil. Guided by the bottle-drift
data, the writer adopts the view that the two equatorial currents
that approach the Brazilian coast north and south of Cape St. Roque
are distinct in their origin, their course, and their destination; and
he distinguishes them by the names, frequently used by other writers,
of the Main and the South Equatorial Currents (pp. 60).

7. It is shown that whilst the mass of the bottle-drift of the North
Equatorial Current strikes the West Indian region north of Barbados,
most of that of the Main Equatorial Current enters the region in
the Trinidad waters to the south of that island. Of a hundred l3ottles
thrown into the last-named current between North Brazil and St.
Paul's Rocks nearly forty would be carried swiftly into the Caribbean
Sea, to be distributed in most cases around its shores ; but sixteen of
them would pass through the Straits of Yucatan into the Gulf of
Mexico, and of these five would reach the Florida seas. Only a few
of them would take the shorter route by the subsidiary Antillean
Stream that flows east of the Lesser Antilles to the Bahamas
(pp. 60-62).

8. The indications of bottle-drift are then used to elucidate the

80 PLANTS, SEEDS, AND CURRENTS

part that would be taken by the South Equatorial Current and its
southward extension, the Brazilian Current, in the distribution of
seed-drift in the South Atlantic; and the same data are employed
to illustrate the current-connections of this ocean with the Indian
and Pacific Oceans. It is shown that bottle-drift can pass from
the Indian Ocean into the South Atlantic round the Cape and may
even reach Brazil, and that it can pass into the same ocean from the
South Pacific round Cape Horn (pp. 62-63).

9. The drifting rate of bottles in crossing the Atlantic is then
treated; and after showing how the disturbing elements connected
with the delay in their recovery may be largely eliminated, a table
of general results is given (p. 66). It is inferred that the average
time occupied in the passage from the West Indian region to Europe
would be about fourteen months at a daily rate of about nine miles,
and it is remarked that the average speed during different stages
of the traverse is not much less. The fact that much slower rates
are indicated by one of the series of the Prince of Monaco's observa-
tions in the North-east Atlantic is explained (p. 68). The return
passage from European waters to the West Indies usually covers a
period of sixteen to seventeen months. But the rate varies in
different parts of the traverse. In the passage south to the vicinity
of the Cape Verde Islands it would be only four or five miles a day ;
whilst in the trans-oceanic passage in the North Equatorial Current
it would be nearly thirteen miles (p. 68).

10. A much greater velocity is attained by bottle-drift in the
swift stream of the Main Equatorial Current — namely, an average
daily speed of thirty miles from the Gulf of Guinea to Brazil
and of forty miles from off the Amazon estuary to Trinidad. About
twelve weeks would generally be occupied in the trans-oceanic
passage from the Gulf of Guinea to Brazil (p. 70). The data furnished
by bottle-drift indicate that Amazon drift, crossing the Caribbean
Sea and the Gulf of Mexico and following the Gulf Stream route,
would arrive in European waters in about twenty months (p. 70).
The average rate of bottle-drift in the Brazil Current does not exceed
ten miles a day (p. 71). It is concluded that the complete circuit
of the North Atlantic (from the Florida seas by the route of the
Gulf Stream, the North Equatorial Current, the Caribbean Sea, and
the Gulf of Mexico) would be accomplished in an average period of
just three years (p. 72). The difficulties in demonstrating the
completion of the circuit by the same bottle are very great. But
it has been almost accomplished by derelicts. The nearest approach
to a complete record is that of the bottle which was picked up on
the west coast of Ireland thirty-four months after it had been cast
into the sea to the westward of the Cape Verde Group (p. 72).

11. Although the indications of the bottle-drift data open up
great possibilities for the distribution of seed-drift in the North and
South Atlantic, each ocean possessing its own independent circulatory
system of currents, it must often happen that the transport of floating
seeds from tropical to temperate latitudes, and vice versa^ has no
effective value. Whilst the North Equatorial Current brings to the
West Indies the sweepings of the Atlantic seaboard of North America,

CURRENTS OF THE ATLANTIC

81

of Southern Europe, and of North-west Africa, the Main Equatorial
carries to the same region the sweepings of both sides of the South
Atlantic. The burden borne westward by the current just named
is, indeed, a motley one. Some of the greatest rivers in the world,
the rivers of two continents, contribute to its freight, the Niger,
the Congo, the Plate, the Amazon, and the Orinoco. Great im-
portance is attached to the fact that the drift of the North and
Main Equatorial Currents mingles in the Caribbean Sea (pp. 73-74).

12. Attention is drawn to the interest that attaches itself to the
island of Trinidad from the standpoint of the dispersal of plants by
currents. It is the great centre of connection between the Old and
the New World and between the South American mainland and the
West Indian islands (p. 74).

13. The probability that Amazon seed-drift reaches the shores of
Europe opens up the possibility of West African seed-drift from the
Congo and the Niger arriving on these coasts by the same circuitous
route — namely, through the West Indies and in the Gulf Stream drift.
This track seems to have been pursued by a bottle which was found
afloat off the coast of Guernsey, after being dropped overboard near
the island of Ascension. Sabine's observation on the transport of
casks of palm oil from the Gulf of Guinea to Hammerfest bears on
this point (pp. 75-76).

14. When we come to balance the account respecting the inter-
change of seed-drift between the Old and the New World, we learn
that in the give-and-take process the gifts from the New to the Old
World would be slight. As a rule they would be unimportant,
ineffective, and casual, and even when effective of a belated kind.
Not for a moment could a comparison be made with the large amount
of effective seed-drift that must be rushed in a few months across
the tropical Atlantic in the streams of the North and Main Equatorial
Currents (p. 76).

15. In conclusion, it is shown that even the North Cape, Cape
Agulhas, and Cape Horn form no insuperable barriers for the passage
of seed-drift (p. 78).

WORKS QUOTED IN CONNECTION WITH BOTTLE-DRIFT
Becher, a. B., in Nautical Magazine for 1843 and 1852.

Berghaus, H., Allgemeinen Lander und Volkerkunde, i., 1837, and Physikalischen
Atlas (Abth. Hydrogr.).

Datjssy, Sur les observations de courants faites au moyen de bouteilles jetees h. la
mer, Comptes Rendus, 1839, viii., 81.

Kohl, J. G., Geschichte des Golfstroms und seiner Erforschung : Bremen, 1868.

Monaco, Prince Albert of, Sur le Gulf Stream: Paris, 1886 (Gauthier-Villars) ;
different papers in Com/ptes Rendus, 1885-92, the final summary and tabulation
of results in tome 114, 1892.

Neumayer, G., Petermann's Geographischen Mittheilungen, 1868.

Page, J., The U.S. Hydrographic Office, National Geographic Magazine, xii., 337 :

New York, 1901.
PuRDY, J., in Columbian Navigator, iii., 31, 1839.
G

82 PLANTS, SEEDS, AND CURRENTS

Rbnnelx,, J., An Investigation of the Currents of the Atlantic Ocean : London, 1832.
Russell, H. C, Journ. Roy. Soe. N.S. Wales, 1894, 1896.

ScHOTT, G., Die Flaschenposten der Deutschen Seewarte, Archiv der Deutschen
Seewartty xx., 1897, Hamburg.

U.S. Hydrographic Office, Washington, Bottle-drift charts on the backs of the
North Atlantic Pilot Charts, October to May, 1900-8.

Wood-Jones, F., Coral and Atolls, London, 1910, pp. 294-6, contains results of
bottle-drift experiments in the Indian Ocean.

CHAPTER IV

THE SIMILARITY BETWEEN THE WEST INDIAN AND WEST AFRICAN
LITTORAL FLORAS AS EXPLAINED BY CURRENTS

The similarity between the West Indian and West African littoral
floras has long occupied the attention of botanists, and particularly
of the late Prof. Schimper. It is a subject that is intimately bound
up with the question of the dispersal of plants by currents; but a
little clearing of the ground is first requisite in order to appreciate
its true significance.

The Discontinuity of Tropical Genera possessing Littoral
Species. — A very noticeable and not infrequent feature in connec-
tion with the littoral trees of the tropics of the Old and New World
is the discontinuous distribution of the genera as far as all the non-
littoral species are concerned. Though the littoral species is in each
case widely distributed in both the western and eastern hemispheres,
the genus is also represented by peculiar species in both worlds, and
in such a manner that we are often left in doubt whether the shore
species has its home in the east or in the west. In all such cases
it is only the littoral species spread by the currents that connects
the two hemispheres. Otherwise the discontinuity would be com-
plete. As examples we may give Chrysobalantis, Entada, Thespesia,
and Ximenia. But this discontinuous distribution raises many
difficulties, whilst it removes others.

Thus, as far as the range of the genus is concerned, the New World
has as much claim as the Old World to be considered the home of
Thespesia populnea, since the six other known species are shared
equally by the two hemispheres. But other genera than those
named above present new points of difficulty. Thus Symphonia
is a genus of twelve or thirteen species, of which nearly all are con-
fined to Madagascar and two occur in Africa. A single estuarine
species, S. globulifera, which connects West Africa with the New World
has apparently no means of crossing the Atlantic. Then we have
Terminalia with a large number of species spread over the tropics
of both hemispheres ; but truly littoral species occur only in the Old
World, and there is no species connecting the two hemispheres.
Then there is Crudya with nearly all its dozen species American.

This discontinuity presents no great difficulties when it affects
genera found in the tropics of both hemispheres which are only
connected together by littoral species that are known to be dispersed

83

84 PLANTS, SEEDS, AND CURRENTS

by currents ; and the same may be said of those genera without littoral
species where there is no connection between America and the Old
World, as in the case of Mammea with six known species, of which
three are restricted to tropical America and three are known only
from Madagascar. Here we are concerned with the original dis-
tribution of the genera in the tropical zone, and the presence or
absence of any link between America and the eastern hemisphere
seems to be a matter of fitness for dispersal by currents. One can
also understand cases like Terminalia, where the absence of any
species linking the two worlds may be concerned with the circum-
stance that the littoral species capable of being spread by the currents
are not found on the West African coast ; but the behaviour of the
genera, Symphonia and Crudya, is not easy to comprehend, since
there we have one genus almost entirely of the Old World with only
a single outpost in America, and another almost entirely American
with a distant representative in the Philippine Islands.

The important lesson to be learned from the discontinuity of
genera in tropical latitudes is that we can only appeal to the currents
in the case of the littoral species, the original distribution of the genus
around the tropical zone being quite another matter. Facts of this
kind go far to limit the sphere of influence of the oceanic current in
determining plant distribution. Currents have done little to con-
fuse the great issues raised by the genera. Whilst they have often
effected the mingling of littoral floras of continents, the main facts
of distribution are largely undisturbed. With these introductory
remarks we will now proceed to discuss the similarity of the West
Indian and West African littoral floras, and in so doing we will take
up again the story of the beach-drift.

An Appeal to the Oceanic Currents. — Perhaps the most im-
portant question raised by the study of West Indian beach-drift is
suggested by the fact that more than half of the plants that con-
tribute to it (beach plants, mangroves and their associates, estuarine
plants, and inland plants that grow at times at the riverside) occur
outside the New World. Almost all of the Old World plants here
concerned have been recorded from West Africa; and there can be
little doubt that the few exceptions, most of which have been
observed on the east side of the continent, will disappear with future
inquiry.

This fact at once leads one to investigate the relation between the
occurrence of these West Indian plants in West Africa and their
suitability for dispersal by oceanic currents. To each of these
plants, as well as to those that are restricted entirely to the New
World, the question has been put, whether or not its fruit or seed,
as the case may be, could be transported without loss of the germina-
tive power in the Main Equatorial Current from West Africa to Brazil.
This, as is shown in Chapter III., is the shortest available route
between the two Worlds for the transference by currents of floating
fruits and seeds. It requires a capacity on the part of the fruit
or seed of floating unharmed from two to three months in sea-
water, and of being able to withstand the ordinary buffeting of the
waves.

WEST INDIAN AND WEST AFRICAN FLORAS 85

The question is put and answered in the table given on p. 86, in the
columns of which are embodied the results of the author's observa-
tions and experiments, as well as literary research, extending over
a period of more than thirty years, and carried out in many localities
both in the Old and the New World. There are not more than three
or four of the fifty-three plants named in the table with which he is
not familiar in their homes, and in all but one he is acquainted
with their fruits and seeds, and has investigated their capacity for
dispersal by currents.

With the exception of the group of small-seeded plants, which,
since they raise other considerations besides those concerned with
currents, are not here dealt with and are discussed in Note 21 of the
Appendix, we have represented in this table the principal littoral,
estuarine, and riverside plants of the West Indies. All offer them-
selves for the application of the test.

Explanatory Notes of the Following Table

(a) The results given in the buoyancy column refer only to the
period during which the seed retains its germinative capacity
whilst afloat. Flotation may continue long after the death of the
seed.

(b) The plants marked ? in the West African column occur in
all probability in West Africa, though in the works of reference at
my disposal that region is not specially particularised, and they
are as a rule merely described as found on all tropical coasts. It
may be assumed that plants like Suriana maritima and Colubrina
asiatica, which are found in the West Indies and in East Africa,
also occur in West Africa, though in the case of the Old World
they are usually only mentioned as existing on all tropical
coasts.

(c) The occurrence of the plants on the Pacific coasts of tropical
America is indicated in the table as far as the data at my disposal
allow. The distribution is often stated in such a general way in
works of reference that it is not possible to learn with certainty
whether or not the plant concerned exists on the Pacific as well as
on the West Indian side of the New World. This is unfortunate,
since the question is one of considerable interest, especially as regards
true littoral plants. It is, however, probable in most of the cases
where no indication is given in the table that the plant also grows
on the Pacific coast.

(d) The list of beach plants restricted to the New World could be
considerably extended if buoyancy data were available; but it is
very doubtful whether any of them would possess seeds or fruits
with great floating powers. One may mention Ernodea litoralis,
Rhachicallis rupestris, and Phyllanthus falcatus. Then there are
plants of Amarantaceous genera, such as Alternanthera and Litho-
phila, as well as different sedges, such as Cyperus brunnem^ etc.,
and grasses, such as Uniola paniculata, Cenchrus tribuloides, etc.

86

PLANTS, SEEDS, AND CURRENTS

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11

88 PLANTS, SEEDS, AND CURRENTS

Tabulated Results of the Preceding Table

Total

Distribution

Fitted for dis-
persal by the

Main Equato-
rial Current

Remarks

New
World
only

Old and

New
Worlds

New
World
only

Old and

New
Worlds

Mangroves and associates
Estuarine plants .

6
6

5

6
1

1

6

The incapacity of
Drepanocarpus is only
inferred.

Plants of inland
wooded districts grow-
ing at times at the river-

12

6

6

1

5

Beach plants ranging
through tropical and
subtropical regions .

16

—

16

—

16

Beach plants confined

LU tllc XNcW VVOIIU aim

West Africa ....

3

3

2

Beach plants confined
to the New World

10

10

3

The number could be
considerably extended,
if buoyancy data were
available. [See previous
Explanatory Note (d).]

53

21

32

5

28

Summary of the above tabulated results.

Of the 53 plants, 32, or 60 per cent., occur in both Worlds, and 33, or 62 per
cent., respond to the current test in their fitness for transport by the Main
Equatorial Current.

Of the 32 plants occurring in both Worlds, 28, or 88 per cent., respond to this
test; but only 24 per cent. (5 out of 21) do so of those confined to the New World,
a proportion that doubtless would be considerably lessened if more buoyancy data
were available.

The plants that are exceptions to the rules.

The three plants that occur on opposite sides of the tropical Atlantic but could
not be floated across the ocean are Andira inermiSf Ecastaphyllum browneiy and
Symphonia globulifera. Possibly a fourth would be Drepanocarpus lunatus.

The five that are restricted to the New World, yet are able to cross the Atlantic
between West Africa and Brazil, are Hippomane mancinella, Morinda royoc,
Sacoglottis amazonica, Sapindus saponaria, and Tournejoriia gnaphalodes.

The Test of Capacity for Dispersal by Currents. — There
are presented in the above table fifty-three West Indian plants of
which thirty-two, or 60 per cent., are found outside the New World,
and in nearly all cases on the shores and in the estuaries of tropical
West Africa. Of these Old World plants all but four, or 88 per cent.,
give an affirmative reply when interrogated as to the fitness of their

WEST INDIAN AND WEST AFRICAN FLORAS 89

fruits and seeds for transport across the Atlantic from the Gulf of
Guinea to South America in the Main Equatorial Current. We
are not concerned just at present with the indications that this test
might yield of a West African origin of many of the West Indian
littoral and estuarine plants. For the moment we will simply
regard this as a proof of capacity for accomplishing the traverse of
the tropical Atlantic. When we regard the twenty-one plants that
are restricted to the New World we find that only five, or 24 per
cent., respond to the test. It should here be repeated that the
list of plants confined to the New World could be considerably
augmented, and that the effect would be to markedly diminish the
proportion of those that respond to the test. With reference to the
five plants that are restricted to the New World, notwithstanding
their capacity for crossing the tropical Atlantic, we shall subse-
quently see that in negativing any reciprocal interchange of littoral,
estuarine and riverside plants between the Old and the New World
they afford a clue to the origin of most of the West Indian plants
of these stations that have been found in the Old World.

(A) Its Application to the Plants in the Mass. — The issue
may thus be stated. Whilst nearly 90 per cent, of the plants that
are common to the West Indies and West Africa possess seeds or
fruits that could be transported by the currents from the Gulf of
Guinea to Brazil, less than one-fourth of those restricted to the
West Indian side possess the same capacity, but have not extended
their range outside the New World. The matter thus resolves itself
into a question of the opportunities offered by the Atlantic currents,
concerning which it has already been brought out in Chapter III.
that whilst the Main Equatorial Current offers a ready and rapid
means of transport for fruits and seeds from West Africa to the
New World, the opportunities of West Africa receiving West Indian
seeds and fruits in a sound condition are small. Reference may here
again be made to the fact that De Candolle in his work on Botanical
Geography (pp. 763-4) places an equal value on the Gulf Stream
and the Equatorial Currents of the Atlantic in the reciprocal exchange
of drift between the opposite tropical regions. This is a serious
error, since the long circuitous route by the Gulf Stream, which
would involve a minimum passage of two years, would for all but a
very few leguminous plants negative any chance of effective dis-
persal. The Brazilian Current would not tap the West Indian region
at all, and the return of any of its seed-drift to tropical Africa would
involve a very lengthy passage and a somewhat complex series of
current connections. The only chance would be that offered by
the Equatorial Counter Current ; but it is shown that the occasions
in which it would extend far enough to the west to tap the New
World as a source of drift would be few, though not altogether
negligible.

(B) Its Application to the Plants according to their
Station. — Having applied this test to the plants in the mass we will
now apply it to them according to their station.

(a) The Mangroves. — In the first place come the mangroves and
their associates, all of which are West African as well as West Indian.

90 PLANTS, SEEDS, AND CURRENTS

The true mangroves comprise Rhizophora mangle, Avicennia nitiday
and Laguncularia racemosa ; whilst their associates at the borders
of the swamp include Anona palustris, Carapa guianensis, and
Drepanocarpus lunatus. With all of them, except the last, con-
cerning which the requisite data are lacking, it is possible that the
Main Equatorial Current could have transported them from the African
coast to the shores of Brazil and the Guianas, but it would be under
varied conditions. Whilst Rhizophora would arrive in the form of
floating seedlings, with Avicennia and Laguncularia the germinating
fruits would be concerned. When pointing out in my book on
Plant Dispersal the obvious risks to which the seedlings and germi-
nating fruits would be exposed during a long ocean passage, I felt
constrained to admit (p. 77) that their capacity for effective dispersal
across an ocean must be postulated.

At that time the position adopted was that America had supplied
West Africa with its mangroves. This I regard now as untenable,
and a later consideration of the current question, as discussed in
Chapter III., has convinced me that an average period of only twelve
weeks would be required for the transport of seed-drift from the Gulf
of Guinea to Brazil, whilst under especially favourable circumstances
this period might be reduced to two months. Though the seedlings
and germinating fruits of the mangroves could scarcely withstand
the wear and tear of an ocean passage of six months, it seems probable
that they would survive a passage of half this duration. With
regard to the floating seeds of plants like Anona palusiris and Carapa
guianensis, which are associated with the mangroves, it is likely
that they could only accomplish an ocean traverse of from two to
four months with sound kernels. For long passages of many months
they would be quite unfitted as far as the preservation of their
effective condition is concerned.

(b) The Estuarine Plants,— ApsiTt from the mangroves and their
associates there are estuarine plants, such as Crudya spicata, Fevillea
cordifolia, Grias cauliflora, Manicaria saccifera, Sacoglottis amazonica,
and Symphonia glohulifera, all of which contribute their seeds or
fruits to the floating drift that is borne seaward and distributed
by the currents. Whilst all the mangroves and their associates are
also West African, five of the six plants just named are confined to
the tropics of the New World. With the exception of Sacoglottis
amazonica there is not one of them, however, that gives promise of
being able to withstand without injury an immersion of months in
the sea, and this oddly enough is not the Old W^orld plant. The
buoyancy of the seeds or fruits may be so great that as with Saco-
glottis amazonica and Manicaria saccifera the fruits have been known
to be stranded on the shores of Europe ; but the indications plainly
show that they would not be in a germinable condition. Yet it is
strange that the plant which is least fitted for oceanic dispersal,
namely, Symphonia globulifera, is the only one of the six that has
been found outside the New World, that is, in West Africa. This
plant is one of the puzzles of distribution, and we shall see its riddle
repeated in one or two other cases mentioned below.

Whilst in Symphonia globulifera we have an estuarine tree growing

WEST INDIAN AND WEST AFRICAN FLORAS 91

on both sides of the tropical Atlantic that could not possibly, as far
as its seeds or its fruits are concerned, have accomplished the ocean
traverse, we have in Sacoglottis amazonica another estuarine tree,
which, although it is restricted to the New World, presents in its
buoyant fruits some capacity for reaching the Old World. In the
first case other influences than those of currents have determined its
distribution. In the second case the determining factors have been
the arrangement of the currents and the insufficiently persistent
vitality of the seeds. Whilst the fruits of Sacoglottis amazonica
could perform the two years' traverse to the African coast by the
Gulf Stream route in the North Atlantic, the seeds would probably
lose their germinative power after six months. Though not im-
possible, the direct route by the Counter Equatorial Current is
largely negatived in this case by the extensive bottle-drift data given
in Chapter III.

(c) Inland Plants growing occasionally at the Riverside. — In con-
nection with West Indian rivers there is another group of plants,
the fruits of which often fall into the stream from the parent plants
growing on the banks beyond the reach of the tide, and are then
carried down to the sea to be distributed far and wide by the currents.
The distinction, however, is a little artificial, since quite half of the
plants would be found at times on the coast ; and there are some, like
Entada scandens, which, though usually growing inland in the West
Indies, are typically littoral in their station in the Pacific islands.
This group can be subdivided into (a) those found in tropical West
Africa, such as the leguminous climbers, Entada scandens^ Mucuna
urens, and Dioclea reflexa, and the trees, Andira inermis and Spondias
lutea ; and (h) those confined to the New World, such as Mammea
americana, Sapindus saponaria, Crescentia cujete, C. cucurbitinay and
the palms Astrocaryum and Acrocomia.

Here there is a certain relation between distribution and fitness
for dispersal by currents. With the exception of those of Sapindus
saponaria, none of the fruits or seeds of the purely New World plants
could accomplish an ocean traverse of two or three months' duration
without loss of the germinative capacity, though capable of floating
for much longer periods in an ineffective state. But even Sapindus
saponaria may not prove to be an exception, since there are indica-
tions dealt with in the special treatment of the plant that it might
be regarded as an Old World species. Of the five plants also at
home in West Africa all but Andira inermis possess seeds or fruits
that could perform in safety the ocean passage from West Africa
to Brazil. In the case of the seeds of the leguminous climbers they
could do very much more, since these seeds retain their germinative
capacity after being carried in the Gulf Stream to the shores of
Europe. Andira inermis presents the same difficulty as Symphonia
globulifera. Though it occurs on both sides of the tropical Atlantic,
it is not able to cross it.

{d) Beach Plants. — We come now to the beach plants, those that
border the beaches and thrive on the sandy tracts in the rear. They
arrange themselves into three groups: the cosmopolitan plants
extending in a general sense over the continental and insular coasts

92

PLANTS, SEEDS, AND CURRENTS

of the tropics and subtropics of both hemispheres, those confined to
the New World and the west coast of Africa, and those entirely
restricted to the New World.

The Cosmopolitan Beach Plants. — In the case of this group we
are dealing with plants that have travelled in most instances prac-
tically around the globe. They include five leguminous species,
Canavalia ohtusifolia, Guilayidina bonduc, G. bonducella, Sophora
tomentosa, and V igna luteola ; two malvaceous species. Hibiscus
tiliaceus and Thespesia populnea ; three convolvulaceous species, if
we include Ipomoea carnosa with /. pes-caprce and /. tuba ; and six
others belonging to as many different orders — namely, Cassytha
filiformis, Colubrina asiatica, Dodoncea viscosa, Sccevola plumieri,
Suriana maritima, and Ximenia americana. There are a few of these
plants that could scarcely be considered as universally distributed
in warm latitudes, but the differences that separate them from the
others are only in degree. Thus both Sccevola plumieri and Vigna
luteola occur on both coasts of the New W^orld and on both coasts
of Africa; but since the first extends to India and Ceylon and the
second exists in Australia, it would be difficult to exclude them.
In giving Ipomoea tuba a very wide distribution I have followed
Urban, and the reasons in the case of /. carnosa are given in the
reference named.

Every one of these fifteen or sixteen widely spread beach plants
has buoyant seeds or fruits (in most cases it is the seed that is con-
cerned) which can float for a long time unharmed in the sea; and
respecting some, such as the two species of Guilandina and Thespesia
populnea, it is known that their seeds can float 'for a year in the
sea without loss of the germinative capacity. A plant has, in fact,
been raised from a Guilandina seed cast ashore on the coast of Ireland.
But there is not a species in this group of beach plants that would
not respond to the test involved in the transport of their seeds or
fruits in a sound condition from West Africa to Brazil in the Main
Equatorial Current, though in the case of Dodoncea viscosa the
minimum limit of flotation-capacity is only just attained.

The Beach Plants restricted to the New World and West Africa. —
When the test above mentioned is applied to the small group of
beach plants that beyond the New World are only known from the
shores of West Africa, we find that two out of the three respond to
it — namely, Chrysobalanus icaco and Conocarpus erectus. The third,
Ecastaphyllum brownei, presents the same problem that was offered
by Andira inermis and Symphonia globulifera amongst the riverside
and estuarine plants. Here we have three plants that grow on the
opposite sides of the tropical Atlantic with to all appearance no
capacity for accomplishing the ocean passage. At first sight it
would seem that the validity of the current hypothesis is here im-
pugned; but in one case, at least, it is likely that quite other con-
siderations arise. Thus Symphonia globulifera, an estuarine tree,
belongs to a genus that is mainly confined to Madagascar, the excep-
tions being two West African species, one of which, as in the present
case, is found in the West Indies. It is obvious that the discon-
tinuous distribution here indicated may not be connected with means

WEST INDIAN AND WEST AFRICAN FLORAS 93

of dispersal at all. A curious question is raised in the case of
Conocarpus erectus, the small seed-like fruits of which possess con-
siderable floating powers. It grows on the Pacific coasts of tropical
America, and its absence from the Pacific islands is remarkable,
since there seems to be no reason, as far as its capacity for dispersal
by currents is concerned, why it should not have reached the eastern
islands of the tropical Pacific. The same difficulty is presented by
the Manchineel tree (Hippomane mancinella)^ a matter which is
referred to below. When dealing in detail with Conocarpus erectus
it will be pointed out that Schimper regarded it as a current-dispersed
plant. On the whole it may be considered that the three beach
plants of tropical America that are only known outside the New
World from the shores of West Africa raise many difficulties.

The Beach Plants confined to the New World. — On the other hand,
when we come to the West Indian beach plants that have not been
found outside the New World we learn that of the ten plants named
in the table the majority do not respond to the test. Whilst most
of them possess fruits or seeds that can only float for a few days or
weeks, in three cases, those of Hippomane mancinella (the Manchineel
tree), Tournefortia gnaphalodes, and Morinda royoc, the floating
capacity covers several months and may extend to a year or more.

To illustrate this point I will take the case of the Manchineel
tree, the fruits of which are one of the most common constituents
of beach-drift in the West Indian region ; and there can be no doubt,
as shown on a later page, that they can float for many months in
the sea with their seeds uninjured. It is a tree that has held its
present area for ages. In the hammocks of the Florida everglades
there have found a sanctuary many West Indian plants that flourished
in the same locality when the hammock-lands represented an ancient
system of keys or low islands that rose from the waters at the time
that the Gulf Stream flowed across the present peninsula of Florida
(Harshberger, p. 230). The Manchineel was one of them. For a
long period currents have afforded considerable opportunities for
the transference of littoral plants from West Africa to the New
World, but very few for a transference from America to Africa.
Yet it may be argued that since the Manchineel grows on the beaches
of the Pacific coast of the New World its fruits could have reached
the Old World across the Pacific. However, the complete traverse
of the ocean would occupy a period of two or three years, a subject
discussed in Chapter XIII. Yet only about half that time would be
required for its fruits to reach the Paumotuan, Tahitian, and Mar-
quesan groups in mid-Pacific, and it is difficult to understand why
the tree has not been recorded from the beaches of the Pacific islands.

It is still more difficult to understand, in the case of the tropical
Atlantic, why, if the Counter Equatorial Current is an effective
agency in seed dispersal, beach plants like the Manchineel, Tourne-
fortia gnaphalodes, and Morinda royoc have not reached West Africa
from the New World, and we may say the same of Sacoglottis amazonica
among the estuarine plants. The time required for this traverse
would be about double that needed for the traverse in the Main
Equatorial Current in the opposite direction, and all these American

94 PLANTS, SEEDS, AND CURRENTS

plants would be able to withstand the six months' passage, as far
as the buoyancy and soundness of their seeds and fruits are con-
cerned. The implication is that the Counter Equatorial Current is
ineffective for this purpose, and if it has not enabled these four
plants to cross the Atlantic and pass the barrier that divides them
from West Africa, it could have offered no opportunity to other
American beach plants, such as Coccoloha uvifera, etc., that are far
less suited for dispersal by currents.

Summary

1. Before dealing with the similarity between the West Indian
and West African littoral floras, a subject intimately bound up with
the dispersal of plants by currents, the ground is cleared by a brief
discussion of the discontinuity of tropical genera, with the object
of showing that whilst we can only appeal to the currents in the
case of the littoral species, the distribution of the genus around the
tropics often raises other issues (pp. 83-84).

2. The important conclusions arrived at in the previous chapter
that the Main Equatorial Current offers a ready and rapid means
of transport for fruits and seeds from tropical West Africa to the
New World, and that the opportunity of their reaching West Africa
in a sound condition from the tropics of the New World is very
shght, are here utilised. Except in the case of the small-seeded
beach plants, where other questions than those of dispersal by
currents are concerned, the test of fitness for transport in the Main
Equatorial Current from West Africa to Brazil is now applied to
the littoral, estuarine and riverside plants of the West Indies. In
answer to the question whether or not they respond to the test,
the following results have been obtained (pp. 84-88).

3. Taking the plants in the mass, nearly 90 per cent, of those found
in the tropics of both the Old and the New World and only 24 per
cent, of those confined to the New W^orld possess seeds or fruits that
would be able to undergo this trial (pp. 89).

4. But this testimony in favour of the currents is not equally
provided by the plants when regarded from their different stations.
Whilst the mangroves with their usual associates and the numerous
cosmopolitan beach plants, all of them typical of both sides of the
Atlantic, respond almost without exception to the test, the majority
of the beach plants restricted to the New World (seven out of ten)
do not comply with it. Similar direct and indirect testimony on
behalf of the currents is supplied by the plants that grow often at
the riverside, especially in the wooded districts above the estuary.
Here the purely New World types are as a rule quite unfitted for
effective oceanic dispersal, while those found on both the American
and the African sides are in most cases adapted for it (pp. 89-94).

5. On the other hand, the evidence of the six estuarine plants points
in the opposite direction, since the only one that occurs outside the
New World is quite unsuited for the ocean traverse, while one of
those that are peculiarly American is well fitted for it (pp. 90-91).

6. It will be therefore observed that although on the whole the

WEST INDIAN AND WEST AFRICAN FLORAS 95

general verdict strongly favours the current hypothesis, there are
some important exceptions. With the mangroves and their asso-
ciated plants, as well as with the cosmopolitan beach plants, the
vote is practically unanimous. With the American beach plants
and with the riverside plants it is a majority vote, whilst with the
estuarine plants the evidence is conflicting and at times apparently
hostile (pp. 89-94).

7. Yet the ultimate tendency of the qualifying cases may not
necessarily be hostile. The implication of the behaviour of such
peculiarly American plants as Sapindus saponariuy Hippomane
mancinella, Morinda royoc, Sacoglottis amazonica, and Tournefortia
gnaphalodes, which possess fruits or seeds well suited for the direct
ocean traverse, may be that the currents have given them no oppor-
tunity of extending their range eastward beyond the New World,
since, as we have seen, the facilities offered by the currents to West
African littoral plants of reaching America are very much greater
than the opportunities supplied to American tropical shore plants of
extending their range to West Africa. But here another difficulty
arises in the case of certain of the littoral plants which border
the beaches on the Pacific coasts of tropical America. It is not
easy to understand why Conocarpus erectus and Hippomane mancinella
that are evidently well fitted for oceanic dispersal, have not reached
some of the easternmost groups of the tropical Pacific through the
agency of the equatorial currents {pp. 93, 94).

8. In the case of plants like Andira inermis, Ecastaphyllum browneiy
and Symphonia glohulifera, which, although existing on both sides
of the tropical Atlantic, have neither fruits nor seeds that could
cross the ocean in a sound condition even by the most direct route,
it is probable that other considerations arise which are concerned
with the original distribution of the genus in both worlds (pp. 92, etc.).

9. Probably the most significant general conclusion in this sum-
mary is given in the third paragraph ; and it is in this connection
essential to remember that if buoyancy data had been available for
several plants not included in the list, the proportion responding to
the test among littoral plants confined to the New World would in
all likelihood have been as low as 15 per cent.

CHAPTER V

lUIIZOPHORA MANGLE AND THE PLANTS OF THE GREAT MORASS OF
THE BLACK RIVER DISTRICT IN JAMAICA

This species of mangrove is so universally spread in the West
Indies that there will be no necessity to name the various localities
in which I found it. My numerous observations on the plant in
Fiji and Ecuador are described at length in my book on Plant
Dispersal. Here I will merely add my West Indian observations,
contrasting them as occasion requires with the results previously
obtained.

On the Period required for the Growth of Rhizophora
Seedlings on the Tree. — Reference will first be made to the length
of time that elapses in different species of Rhizophora between
fertilisation and the fall of the seedling from the tree. In the work
above named (pp. 457, 466) it is stated that whilst Jacquin in the
West Indies placed this period at eleven to twelve months for
Rh. mangle y my own observations in Fiji for the same species gave a
result of eight to nine months. The considerable variation in the
length that the seedling attains on the tree will explain this differ-
ence. For Rh. mucronata in Fiji, I placed the period at about ten
months. These results may now be supplemented by those given
by Kerner in his Natural History of Plants (Oliver's translation,
I., 603) for another Asiatic species, Rh. conjugata. Apparently
quoting Ransonnet, he writes that the hypocotyl reaches its full
length of 30 to 50 cm. in from seven to nine months. With these
results we have now the requisite data for all the three species that
are usually recognised as constituting the genus Rhizophora^ and the
view expressed in my work that a period of nine or ten months is
typical of the genus thus holds good.

On the Ability of Rhizophora Seedlings to withstand
Drying. — It is remarked in my previous work (p. 461) that stranded
Rhizophora seedlings would be able to withstand drying for months,
provided that they were protected by a covering of vegetable drift
or of sand; and an experiment in Fiji is described in which two
stranded seedlings, kept dry in my room for nine weeks, developed
leaves and roots when afterwards planted in the mud of a mangrove
swamp. However, the results of a more recent experiment on
W^est Indian seedlings, which are given below, indicate that under
favourable conditions seedlings can retain their vitality in the dry
state for five months ; and one cannot doubt that, if the experiment
had been conducted under more natural conditions in the tropics,

96

RHIZOPHORA MANGLE

97

the results would have been still more marked. It is well known
that these seedlings readily strike when stranded on a mud-flat, and
my observations show that they do the same on a sandy beach,
though often abortively. The point here investigated is their
capacity of postponing this process.

On the Vitality of Seedlings of Rhizophoba mangle which had been kept
Dry for Five Months after being gathered from the Tree

(They varied in length from 6-6 to 12-3 inches (168-312 mm.), and were detached
from the fruit-case. The experiment was carried out during June and July in
England in a greenhouse, and, therefore, under warm conditions. The measurements
were made from the base of the plumule to the tip of the hypocotyl.)

Dried Seedlings

Increase in Weight | Increase in Length

Five seedlings kept afloat between
4 and 5 weeks in fresh water.
Original length in dry state, 6-6 to
8*9 inches.

17 to 25 per cent.

0-2-0-3 inch(5-7|mm.)

Three seedlings kept afloat be-
tween 4 and 5 weeks in sea -water.
Original length in dry state, 6-6 to
12-3 inches.

10 to 20 per cent.

0-2 inch (5 mm.)

Two seedlings kept afloat between
4 and 5 weeks in sea-water. Original
lengths in dry state, (A) 8-9 inches,
(B) 12 inches.

(A) 54 per cent.

(B) 48 per cent.

(A) 0-6 inch (15 mm.)
(B) 1-0 inch (25-4 mm.)

All the seedlings were much shrunken, wrinkled, and blackish
along their whole length, with the exception of the lower end, which,
for a distance of from one to two inches from the tip of the hypocotyl,
retained a bright green hue and was less withered. Evidently the
seedlings in fresh-water regained only a part of the water that they
held in the living state, and the small increase in length of from
5 to 7 mm. was in the main the result of the swelling process.
Three of them placed in sea- water behaved like those in fresh- water,
and here it is also apparent that little or no actual growth occurred.
However, two of those in sea- water behaved very differently. They
absorbed, relatively speaking, twice or three times as much water,
and increased their length in the one case by 15 mm. and in
the other by 25 mm. The growth was hypocotylar, since the
measurements were made from the base of the plumule to the tip
of the hypocotyl. Rootlets were not developed. No effort was
made to unfold the plumular leaves, nor was there any marked
increase in length of the plumule, such as could be attributed to
growth.

This experiment is interesting from the fact that it supplied its
own " control " in the case of the three seedlings that behaved in
sea-water like those in fresh-water and showed no active growth.
One of the implications is that Rhizophora seedlings, after falling

H

98 PLANTS, SEEDS, AND CURRENTS

into the sea from the tree, may proceed with the hypocotylar growth
whilst afloat, though probably rootlets would not be produced. This
g^o^vth would naturally be more marked than in the case of the
dried seedlings experimented on. We would expect that in ordinary
circumstances the floating Rhizophora seedling, if prematurely
detached, would add some inches to its length.

However, it does not appear that growth is long continued in the
case of fruits, detached in the early stage of germination, which fall
into the sea. Germinating fruits, with the hypocotyl protruding
half an inch or less, may be at times broken off from the tree through
the agencies of storms and animals. Such fruits sink at once, and
it was ascertained by experiment in fresh-water that although the
germinating process was continued for the first five or six days
under water, the protruding portion adding about 3 mm. to its
length, the hypocotylar growth was arrested after a week. Fruits
of full size, but displaying no protrusion of the radicle, made no
attempt to do so whilst lying for a fortnight in fresh-water. The
curious appearance of a Rhizophora fruit in the early germinating
stage, which had been broken off and was lying in the ooze under
the tree, led me to plant a number of such fruits in the mangrove
mud with the hypocotyl in the air, thus reversing the normal position.
Under these unusual conditions fruits with the seedling protruding
between 12 and 18 mm. added from 2 to 3 mm. to the length of the
hypocotyl during the course of three weeks and remained in most
cases quite healthy.

The Proportion of Germinating Fruits of Rhizophora

MANGLE that DISPLAY MORE THAN ONE SeEDLING. In my book

on Plant Dispersal (pp. 449, 466) I deal with the fact that whilst, as
a rule, only one of the four ovules in a fruit of Rhizophora becomes a
seed, occasionally two seeds and even three seeds are developed.
Out of more than 2000 germinating fruits of Rh. mangle examined
in Fiji, mainly in the Rewa delta, about 1 per cent, displayed more
than one hypocotyl. In these cases there were usually two and very
rarely three hypocotyls, the rate of frequency of fruits displaying
three seedhngs not exceeding 1 per 1000. These results apply to
the total number of fruits observed, but there were localities in
which the proportion of fruits bearing more than one seedling
amounted to between 2 and 3 per cent.

These observations were extended in the West Indies in the case
of the same species, about 1000 germinating fruits being examined,
500 of them in the delta of the Black River, Jamaica, and the rest
at St. George's, Grenada. In the locality first named just 2 per
cent, displayed two seedlings, no fruit with three hypocotyls being
noticed. But considerable variation was exhibited by different
trees. Thus, whilst one tree gave a proportion of less than 1 per
cent., another gave a value of 6 per cent. In Grenada. I obtained
quite phenomenal results, the fruits of five trees examined yielding
a proportion of 7J per cent, with two hypocotyls, none with three
being observed. But the proportions varied greatly, the respective
results for the different trees being 16, 11, 7, 3, 1 per cent. The
rate of frequency obtained by Baron von Eggers in the tropics of the

RHIZOPHORA MANGLE

99

New World was very small, namely, 3 per 1000 (Plant Dispersal,
p. 450).

The Length attained on the Tree by Seedlings of Rhizo-
PHORA MANGLE. — In Jamaica, as in Fiji and Ecuador, I found that
the average length attained by seedlings on the tree, the measure-
ments being taken from the base of the plumule, was from nine to
ten inches. In all three regions, when growing in sheltered situations,
they may attain a length half as long again. But it would seem that
this maximum is at times greatly exceeded in the New World. Thus
I found washed ashore on the weather side of Tobago, mingled with
much Orinoco drift, several seedlings sixteen to eighteen inches long,
and in one case twenty-two and a half inches in length. It is quite
possible, however, if these seedlings had been a long time afloat in
the sea, that their hypocotyls may have grown in length, a subject
discussed above.

The Absence of Dimorphism in Rhizophora mangle in
Jamaica and other West Indian Localities. — In different
localities in the West Indies, as in Jamaica, the Turks Islands, and
Grenada, I endeavoured to ascertain if Rhizophora mangle exhibited
the dimorphism displayed by the species in Ecuador. In my book
on Plant Dispersal (pp. 445, 487) it is shown that in Ecuador
there are two forms : the one " mangle chico," ten to fifteen feet
high, growing in the seaward and landward margins of the swamps ;
the other mangle grande," which attains a height of sixty or
eighty feet and composes the interior of the swamp. The last in
some of its characters approaches Rhizophora mucronata, the Asiatic
species. However, after careful inquiry in the Black River and
Savanna-la-mar districts of Jamaica, I could not discover any per-
sistent evidence of dimorphism. Although there was often a con-
siderable contrast in height and size between the Rhizophora trees
fronting the sea and those growing in the midst of the swamp and on
the banks of estuaries, the former frequently only ten or twelve feet
high and the latter attaining heights of sixty or seventy feet, the
floral characters as a rule remained much the same. Only in a few
cases did there seem a tendency to the development of the " mangle
grande " type in the taller trees. It may be that Rhizophora
racemosa (a form of Rh. mangle where the stalk of the inflorescence
branches two or three times), which was long ago differentiated by
botanists, may answer to the " mangle grande " type. The two are
separated in Hooker's Niger Flora. However, the " mangle chico "
is evidently the West Indian form. The plants of the Turks Islands
were all of this type, and, as far as examined, those of Grenada and
Tobago. On the parts of the coast of Porto Rico visited by Dr.
Millspaugh the tree " seldom attains a growth of over ten feet in
height " (Plantce Utowance, Pt. I.). In the West Indies I never
came upon any seedless form of Rhizophora, such as I have described
in the case of the " Selala " of Fiji (Plant Dispersal, p. 443).

On the Influence of Varying Degrees of Salinity on the
Station of Rhizophora mangle. — A promising field of inquiry
would lie in the systematic determination with the hydrometer of
the influence of varying degrees of salinity on the distribution of

i

100 PLANTS, SEEDS, AND CURRENTS

plants in the estuaries and coast swamps of tropical regions. An
investigation on the lines of that pursued by Prof. Harshberger on
the salt-marsh and estuarine plants of the New Jersey coast would
yield valuable results (vide Proc. Amer. Philos. Soc, Sept. 1911).
For such a study the true mangroves of the genus Rhizophora would
offer abundant materials. Though I have made observations on
this subject with reference to species of Rhizophora, and particularly
Rh. mangle^ in different parts of the tropics, they have been discursive
in their nature, and, as will appear, they supply rather hints for
further inquiry than conclusive and determinate results.

In Fiji, where I made a special study of Rhizophora mangle, the
American species, and of Rh. mucronata, the Asiatic species, I found
that whilst they both throve at the coast, only the first named was
also at home in the brackish water of the estuaries. This double
station, in the coast swamp and in the estuary, was displayed by
Rh. mangle in Fiji, in Ecuador, and in Jamaica. In all three localities
I ascertained that the tree could live in the higher parts of an
estuary where the water was at certain states of the tide quite fresh,
and at others brackish or slightly salt. But my data showed that
however well it might adapt itself to fresh- water conditions for some
hours of each day, it would not be able to live in the parts of the
estuary altogether beyond the reach of the sea-water. Typically,
Rh. mangle is a tree of the coast swamp and of the mouth of an
estuary where the sea- water has in a general sense much of its normal
salinity. Its seedlings can be transported by the currents to islets
in the open sea, where they give rise to mangrove colonies, such as
are presented by the Florida sand-keys. If it is able to adapt itself
to the slightly salt or even to the fresh water of the interior of an
estuary, it is only for a portion of the day. Rh. mangle is primarily
a plant of the typical salt-water swamp of the tropical sea border.

Yet its adaptability to less saline conditions invites inquiry. As
stated in my book on Plant Dispersal (p. 442), it extends in Fiji to
the higher reaches of the estuaries, where the density of the water
varies according to the state of the tide between 1*000 and 1*010. Its
behaviour is the same in Ecuador. In the Guayaquil River it grows
forty miles up the estuary, where the water is potable and has a
density of 1*000, except at high water, when it is brackish (Ibid.,
p. 486). In the channels at the back of the city of Guayaquil, to
which the sea-water has freer access, the water at high tide had a
specific gravity of 1*014; and in response to the increased salinity
there was a more typical development of the mangrove formation,
Rh. mangle fronting the water with. Laguncularia racemosa and
Avicennia in the rear. In the case of the Santa Rosa River, which
opens on the Ecuador coast near Puerto Bolivar, Rh. mangle,
though abundant at the coast, failed altogether about ten miles from
the mouth of the estuary, where the water was quite fresh during
nine out of the twelve hours, being salt only in the latter part of the
rising tide.

In the Black River of Jamaica I obtained similar results in the
month of January. In the company of Laguncularia racemosa this
Rhizophora ascends the main channel of the estuary for two and a

RHIZOPHORA MANGLE

101

half or three miles ; and though it thrives where the water has the
density of fresh-water during most of the twenty-four hours, except
towards high tide, when the hydrometer indicated 1*002 and 1*003,
it disappears when the water is permanently fresh. In the Salt
Springs branch of the estuary the same thing occurred. Rhizophora
mangle grew on the banks for the first two or three miles of the
ascent, when the specific gravity of the water varied between 1*000
and 1.003; but it disappeared altogether from the river-ba^iks a
mile or two further up, where the water was permanently fresh.
The mode of its disappearance was remarkable, the trees not only
diminishing in numbers, but very markedly in size. It is thus
described in my journal : *' Whilst ascending from Salt Springs to
the Blue Hole fine specimens of Rhizophora trees, fifty feet high, lined
the banks in places for the first half-mile. After this the trees were
scanty, and became smaller and smaller as we penetrated further into
the Great Morass, until, at about a mile and a half above Salt Springs,
the trees originally fifty feet in height, were reduced to shrubby,
sickly-looking growths, and shortly disappeared."

Probable Infiltration of Sea-water into the Interior of
THE Great Morass of the Black River. — The name of Salt
Springs, which is given to one of the principal branches of the Black
River estuary, would seem to indicate that salt water wells up in
the midst of the Great Morass in which the place thus called lies.
In spite of the name I could learn of no such phenomenon, but it
is not unlikely that sea-water does penetrate for some distance
through the lower portion of the dense mass of plant-growth that
forms the surface of the morass. Beneath the plant-growth lies a
platform of the rag-rock of the district, a limestone seemingly com-
posed in the main of old reef detritus, and not infrequently bared to
view. The Great Morass, the general vegetation of which is described
later in this chapter, extends inland for five or six miles as the crow
flies, and is raised but a few feet above the sea. There is some
ground for holding, as is explained below, that the salt water ascends
much farther up the river along its bottom than is indicated by the
density of the surface-water. But, apart from this, it would be
strange if the sea-soaked mangrove swamps of the coast, which are
physically continuous with the inland swamps of the Great Morass,
did not favour the landward infiltration of sea- water.

In the case of the Machala plains on the coast of Ecuador, where
low-lying districts extending several miles inland constitute the sea
border, I have shown that this takes place on an extensive scale
{Plant Dispersal, p. 485). Here there is continuity in the soil-cap
between the mangrove belt of the coast and the arid plains miles
inland. The rise in level being only a few feet, the e^^ects of the
sea-water infiltration are evident on the surface far from the coast
in a saline efflorescence on the soil. The stages of the infiltration
landward of sea- water are displayed : first, in the mangrove swamps
a mile or two in width daily overflowed by the tide ; second, in the
salt-encrusted mud-flats in their rear, which are overflowed only by
the higher tides, and support plants like Salicornia, Sesuvium, and
Batis maritima ; third, in the vegetated plains still farther behind.

102 PLANTS, SEEDS, AND CURRENTS

which extend for miles inland, and, though sufficiently raised above
sea-level to be above the reach of the tides, are nevertheless soaked
with sea- water, that displays its presence in the salt left by evapora-
tion on the surface of the ground. On these plains, at a distance of
four miles from the coast and probably extending much farther
inland, there flourishes a dry jungle-type of vegetation of the xero-
philous kind, such as Algaroba trees (Prosopis), cactaceous plants,
and several sorts of prickly shrubs.

Those who live near rivers in houses built on alluvial soil know
that when the river is in flood the water rises through the basements
of their dwellings long before the river overflows its banks. This
is well illustrated in the delta of the Mississippi, as at New Orleans,
where the graves have to be erected on the surface of water-soaked
ground. When low-lying districts of alluvial formation front the
sea, the salt water must often be found a short way below the surface
far inland.

It would, therefore, be a matter for surprise if the subsoil water
of the low-lying region of the Great Morass in the Black River
district of Jamaica did not often hold in solution much saline material
at a distance of two or three or more miles from the sea border of
the swamp. But little indication of the infiltration of sea-water in
the subsoil might be offered by the surface-waters of the morass;
and mangroves, thriving away from the coast in a seemingly fresh-
water swamp, may actually have their roots immersed in a salt-
impregnated substratum.

It is not difficult to show, as I have already done, that on the
banks of a river Rhizophora mangle gradually dwindles away, as one
ascends the stream, until it disappears altogether when the water
is permanently fresh. But away from the streams in the midst of
the Great Morass, where the surface water varies in density only
between 1*000 and 1*001, there occur in the Black River delta, a
couple of miles from the coast, isolated belts of tall Rhizophora trees,
fifty or sixty feet high, which seem strangely out of place in the
midst of a dense growth of Typha. I was told by my coloured
companions that these inland belts of Rhizophora are situated around
shallow pools infested by alligators. I could not do more than
examine the margin of one of these belts ; but I remarked the rela-
tive thinness of the leaves of the trees. They would be worth a
careful examination by a resident. It would seem probable that
salt water here wells up through the swamp, or at any rate approaches
the surface.

The Underflow of Sea-water in Estuaries. — An important
factor in influencing the stations of plants in tropical estuaries is to
be found in the circumstance that whilst the surface water, more or
less fresh in character, is running down, there may be an under-
current of sea-water running up. Thus opposite Puna, at the
mouth of the Guayaquil River, I found on one occasion that while
the surface water with a density of 1*010 was running down, my
thermometer, when lowered to a depth of two fathoms and more,
was carried up-stream by a strong undercurrent, which extended to
the bottom at a depth of seven fathoms. Evidently the sea-water

RHIZOPHORA MANGLE

103

was making its way up the estuary beneath the down-flowing fresher
surface water, but the differences in temperature were very sHght.
During the two days that we lay in quarantine off Puna the density
of the surface water ranged between 1-004 and 1-016, being saltest
after the tide had been running up for a while. Some time after
the tide had commenced to flow," the whole mass of the river
water turned up-stream. The result of this delay in the backing of
the water was that the duration of the up-going tide was shorter
than that of the ebbing tide. This contrast increased with the
ascent of the estuary, so that at Guayaquil, forty miles from the
sea, the reversal of the downward current occupied only a short
time.

The undercurrent of sea-water ascending an estuary is a common
feature in the regime of a river, and it is one that must have a
definite relation with the stations of plants growing at the water-
side. With this feature is doubtless to be connected the curious
fact that the water may continue to rise after the ebb has begun at
the surface. It is apparent that in a tidal estuary a multitude of
lines of inquiry offer themselves to an investigator with the
hydrometer.

In some cases, however, valuable indications may be obtained
from differences in temperature. When one finds in an estuary that
the water at the bottom is warmer by some degrees than the water
at the surface, the existence of an undercurrent of sea-water may be
surmised. Suspecting that there was an up-current of sea-water
below the surface fresh- water of the Black River estuary in Jamaica,
I made some observations, at noon in the month of January, in the
main stream between the bridge opposite the town and the junction
of the Salt Springs River, a mile further up, the depth varying from
three to three and a half fathoms. Having first ascertained that the
temperature of the sea was about six degrees (Fahrenheit) warmer
than that of the river, the sea being 80° and the river 74°, I proceeded
to compare the surface and bottom temperatures of the river. A
number of observations made in the part of the estuary above stated
gave closely similar results, which I may sum up in the remark that
whilst the downward surface-current of fresh- water (density I'OOl)
had a temperature of about 74°, the water on the river bottom
showed a temperature of 78° F. Here it was evident that the salt
water was ascending the river beneath descending fresh-water, and
that the influence of the dissolved salts in the sea-water was more
than sufficient to counteract the decrease in density due to its higher
temperature. Within the mouth of the Salt Springs branch of the
estuary the difference between the surface and bottom temperatures
was only two degrees, and a little higher up there was none at all.

The complicated Problems offered in the Thermometric

AND HydROMETRIC INVESTIGATION OF A TiDAL EsTUARY. A multi-
plicity of considerations arise when we regard the influence on plant
stations of the greatly varying conditions of temperature and salinity
in different parts of a tidal estuary; and their complexity deepens
when we contrast the regimes of different seasons. The whole
subject of the economy of an estuary, as revealed by the thermometer

104 PLANTS, SEEDS, AND CURRENTS

and hydrometer, is here opened up, and it presents many very com-
plex problems. It would be futile, however, to speculate now on
the various working values to be assigned to the increase in density
due to the fall in temperature and to the increase arising from dis-
solved saline materials. We will leave the problems offered by this
contest between the elements to the future investigator, and will
content ourselves with the reflection that much light will be thrown
on the conditions which determine the stations of plants in a tidal
estuary by such a systematic employment of the hydrometer and
thermometer as was exhibited in Prof. Harshberger's investigations
on the estuarine plants of the coast of New Jersey.

The Springs of the Black River Morass, as Illustrated by
THOSE OF THE Blue Hole. — It is Hkcly that the numerous springs
of fresh-water which well up in different parts of the Great Morass
supply a large proportion of the water that the Black River dis-
charges into the sea. One of the best known of these springs is the
Blue Hole, which lies, as the bird flies, four or five miles from the
coast, and is reached by way of the Salt Springs tributary, of which
it is one of the main sources. These springs, which are distant about
a mile from the foot of the neighbouring range of hills, issue in a
funnel-shaped, well-like hole about forty feet deep and sixty feet
across. The considerable body of water which here escapes is carried
away in a stream, the channel of which is almost blocked by aquatic
plants, that grow here in great luxuriance. On January 7, 1907, at
noon, the temperature of the Blue Hole was 75'5-76° F. at the
bottom, and 77° at the surface, that of the river below, which received
its waters, being 76-77°.

A rich growth of aquatic and semi-aquatic plants is characteristic
of the large and copious head-springs of rivers in most parts of the
world. Here under comparatively uniform thermal conditions,
where the yearly range of the water-temperature often corresponds
approximately to the limited range of the monthly means of the
air-temperature in the shade, the aquatic plants thrive vigorously
throughout the year. For the whole twelve months it is probable
that the range of temperature of the water in which the vegetation
around the Blue Hole is bathed would be only 75 to 82° F., which is
the usual range of the monthly means of the temperature of the air
in the lowlands on the south side of Jamaica. (See a paper by the
present writer on the temperature of springs in the Journal of the
Royal Meteorological Society, about 1895, and papers on river-
temperature in the Proceedings of the Royal Physical Society of
Edinburgh, 1896.)

The plants grow in greatest profusion in the stream leading
immediately from the Blue Hole. Largely occupying its channel
and often carpeting the bottom are masses of Isnardia palustris,
Hydrocotyle umbellata, Potamogeton plantagineus, etc. There also
flourish here in the shallows Sagittaria lancifolia and a pretty yellow-
flowered Utricularia. Pistia occidentalis fills up little recesses in the
oozy banks, propagating its kind vegetatively with rapidity. In the
river below Ceratophyllum demersum grows in the shallows.

The Vegetation of the Black River District. — This may be

RHIZOPHORA MANGLE 105

conveniently described under three heads : (a) the aquatic and semi-
aquatic plants of the river and the riverside; (/;) the plants of the
Great Morass, a region of swamp traversed by the Black River and
its tributaries ; (c) the plants of the mangrove formation.

(a) The Plants of the River and the Riverside. — Lining the banks
above the mangroves is a tall reed-growth of Cyperacece (Cyperus
elatus, etc.) and Typha angustifolia, with which are associated
Sagittaria lancifolia, which attains a height of four or five feet,
Chrysodium vulgare (the Swamp Fern), a species of Jussicea, Pavonia
corymbosa (a malvaceous shrub). Polygonum glabrum, etc., all of
which grow more or less in the water or in the swampy borders. In
the shallows grow the Water Hyacinth (Pontederia) and Nymphcea
ampla, the last covering the large expanses of water into which the
rivers occasionally broaden out. Amongst the more or less sub-
merged aquatic plants are Utricularia (near U. ohtusa), Potamogeton
plantagineuSy Ceratophyllum demersum, Isnardia palustris, Hydrocotyle
umbellata, etc. Pistias grow scantily in the recesses of the banks of
the main channels, but are especially abundant in the vicinity of the
springs that well up in different localities of the Great Morass, and
nestling amongst them little floating masses of Azolla may be at
times observed.

(h) The Vegetation of the Great Morass in the Black River District. —
This broad, savannah-like region, elevated but a few feet above the
sea, extends some six or seven miles inland to the foot of the moun-
tains. Looking down upon it from the slopes behind, one would
imagine that one was gazing at some arid plain where clumps of tall
palms serve to vary the monotony of a landscape in which Nature
has been niggard in her ways. This notion would receive fresh
colour when we observed the rivers winding through the plain and
the dark green belts of trees that in places marked their courses.
Yet we are not looking at a waste but at a swamp, where the ground
is soaked with water as a sponge, where copious springs well up, and
where the alligator finds a home.

The tall palms are the Thatch Palms (Sabal umbraculifera), and
they grow in the midst of a swamp- jungle largely composed of a
reed-growth of Typha, Cyperacece, and other similar plants. We
should often find no footing in the marshy ground ; and if we wished
to examine the district, we must pole along in a canoe through
narrow channels more or less blocked by vegetation. In one place
we should be traversing an area of several acres occupied only by
Scirpus plantagineuSy growing to a height of three feet, and sugges-
tive in its appearance of an Equisetum. In another place we should
find the surface carpeted with Herpestis monniera. A third locality
would be appropriated by the Swamp Fern {Chrysodium vulgare).
But more often the eye would rest on the tall reed-growth of grasses
{Arundo, etc.) and sedges (Cyperus, etc.) and bulrushes {Typha) that
monopolises most of the surface. Conspicuous amongst the swamp
vegetation are the Pavonia trees, or rather shrubs {P. corymbosa) ;
whilst, strangely enough, Conocarpus erectus, a plant typically
halophilous in its station, is one of the most frequent among the smaller
trees in this fresh- water morass in places where the ground is firmer.

106

PLANTS, SEEDS, AND CURRENTS

Coming to the vegetation of the banks of the Black River, as it
winds through the Great Morass above the mangrove, the most
conspicuous feature is presented by the trees that Hne its sides in
places. This subject is dealt with at length in Chapter I., when dis-
cussing the Black River as a source of drift, and I must refer the
reader to that description for an account of a character of the
Great Morass that was probably much more pronounced before the
arrival of the white man.

(c) The Plants of the Mangrove Formation. — The mangroves of the
Black River district are mostly confined to the lower part of the estuary
and to the part of the Great Morass that lies nearest to the sea.
Whether in the swamps or at the riverside, they do not usually
extend more than two or three miles inland. In both cases they
present the same arrangement, the belt of Rhizophora mangle at the
water-front being backed by a growth of Laguncularia racemosa and
Avicennia nitida. In localities near the coast Batis maritima and
Salicornia flourish on the mud beneath the mangroves. An account
of my observations on Rhizophora mangle in this district will be found
on an earlier page of this chapter.

The Savanna-la-mar District of Jamaica. — This region in-
cludes the Great Morass of Westmoreland, where most of the features
of the Black River Morass are reproduced. I will here give the
results of observations made during my sojourn of a week or two in
the district. One of the most instructive journeys through the low-
lying, swampy regions of Jamaica may be made from Savanna-la-
mar to Negril, a traverse of fifteen or sixteen English miles. For the
first third of the distance, where the mangrove-lined creeks run in
far from the coast, one's attention is mainly occupied with the inland
extension of Rhizophora, Laguncularia, and Avicennia, and with the
large tracts of muddy ground exclusively occupied by Batis maritima.
In the middle third we have left the salt-water swamps behind, and
now traverse a region of fresh-water swamp much like that of the
Great Morass of the Black River district. Here flourish Sabal
umbraculifera, Typha angustifolia, Sagittaria lancifolia, Cyperacece,
and others of the Black River marsh plants. In the last third we
encounter the characteristic vegetation of the lower hills, with
Grias cauliflora growing at the sides of the streams, but we meet
the mangroves again on approaching Negril. Britton, who com-
pares the Great Morass of Westmoreland with the Everglades of
Florida, noted the presence here of Crudya spicata (Harshberger's
Phyt. Surv. N. Amer., p. 678), which, as observed in the first chapter,
is a riverside tree in the Black River Morass.

Among the small rivers that discharge into the sea near Savanna-
la-mar is the Cabarita. Here the mangroves, chiefly represented by
Rhizophora mangle, ascend the stream for about a mile from the sea,
being associated with Grias cauliflora at their upper limit. In the
swampy land bordering the river, where the mangroves fail, flourish
Typha angustifolia, Cyperus elatus (a tall, papyrus-like sedge), and
Arundo saccharoides ; whilst Coix lachryma sometimes covers large
surfaces of wet ground. The banks displayed more than one species
of Polygonum, including P. glabrum, and a species of Commelyna was

RHIZOPHORA MANGLE

107

especially frequent. The Water Hyacinth (Pontederia), Potamogeton
fluitans, and Ceratophyllum demersum grew abundantly in the stream ;
whilst occasional young Pistias and small portions of Azolla were to
be observed on the surface.

I ascended for about 100 yards Bowen's River, a small stream
twenty-five to thirty feet across and infested by alligators, which
lies about three miles east of Savanna-la-mar. Whilst Typha and
Sagittaria grew on the borders. Polygonum glabrum, a pretty blue
Commelyna, and Hydrocotyle umbellata flourished at the margins and
in the shallows. Ceratophyllum demersum grew in dense submerged
masses, and in shallow places near the banks the surface of the
water was covered with Azolla.

The Great Lake at Pondside near Black River. — This is a
large sheet of fresh-water less than a mile in length and ranging, as
I found, between one and a half and two and a half fathoms in depth.
Alligators here find a congenial home. They lay almost submerged
across the path of the canoe, and sank slowly as we approached. For
this reason I could not examine properly the abundant, tall reed-
growth at the margins, my little craft being frail and leaky, whilst
my coloured companion was too much scared to be of use to me.
Nymphcea ampla grew in abundance, for the most part in the shal-
lows; but even in the centre of the lake solitary plants with very
slender stems rose up to the surface from a depth of ten feet. Utri-
cularias, not in flower, were associated with the Nymphaeas; and
Potamogeton plantagineus thrived in all the shallower waters, with
Sagittaria lancifolia at the borders. In marshy places, where springs
rose up on the side of the lake, I noticed the Dumb Cane {Dieffen-
bachia seguine). I visited this lake a few days after the great earth-
quake at Kingston in January 1907, and was told that " the water
rose up in large waves like the sea."

The District of the Salt Lakes near Black River, Jamaica.
— Bordering the sea-coast a few miles to the east of Black River lies
the district known as the Salt Lakes. Here are a number of shallow
salt-water lagoons in the midst of extensive mud-flats and swamps.
A detailed topographical description would be here out of place ; but
one may say that this region of lagoons is backed by the Great
Morass, and that it is fronted by the sea-beach. The lagoons vary
much in size, the largest being known as the Great Salt Lake, which
is nearly a mile in length, and at the time of my visits in January
1907 scarcely a fathom deep, the greatest soundings obtained being
usually four or five feet. Separating the lagoons from the sea is a
low strip of land varying in width between a few yards and a quarter
of a mile. Under ordinary conditions, such as prevailed at the time
of my visits, these lagoons are cut off from direct communication
with the sea. The Great Salt Lake, it is true, has a narrow, tortuous
channel leading to the coast, which is known as the Creek. But at
ordinary times there is no passage here through the beach. How-
ever, in the rainy months, as in May and October, when much of the
Salt Lakes district is submerged by the waters draining coastward
from the Great Morass, the waters force their passage and the Creek
remains open for a while to the sea. But Nature is sometimes slow

108 PLANTS, SEEDS, AND CURRENTS

in giving relief to the submerged region, and the people of the neigh-
bourhood then dig a trench through the beach for carrying off the
surplus water.

It is therefore evident that the hydrographical features of the
district of the Salt Lakes vary greatly in different seasons. Although
the drainage of the waters from the Great Morass is relatively small
for most of the year, it is large in the wet months. After the rains
the lagoons are greatly increased in size and their water is nearly
fresh. During the dry months they shrink considerably and become
very salt, the smaller lagoons being sometimes completely desiccated
or reduced to scanty lakelets only a few inches deep. This alterna-
tion between a state of high salinity and a condition when the water
is almost fresh must have an influence on the distribution of the
vegetation.

When I visited this locality in the middle of January intermediate
conditions prevailed, such as exist probably through the greater half
of the year. Some of the lesser lagoons had dried up, being repre-
sented by expanses of white mud. Others were reduced to ponds a
few inches deep, the water being very warm and very salt. In the
case of a greatly shrunken lagoon nearest to Paroti Point, the density
and temperature of the water at midday were respectively 1'031 and
88° F., the values for the sea at the same time being 1*026 and 79° F.
In the larger and deeper lagoons the contrast between their salinity
and that of the sea was slight. Under similar conditions of tempera-
ture the salinity of the water was 1-028 and that of the sea 1*026.
At first sight the Salt Lakes district would appear to be well fitted
for the salt-pan industry, but the fresh-water from the great inland
swamps, especially after the rains, would probably prevent the
success of such an undertaking.

General Character of the Vegetation of the Salt Lakes
District. — Avicennias among the trees and Salicornias amongst the
lesser plants form the predominant features of the vegetation occupy-
ing the extensive expanses of white mud that give the character to
the district of the Salt Lakes. Then come the mangroves at the
borders of the larger lagoons, and here the same Avicennia {A.
nitida) takes its place with Rhizophora mangle and Laguncularia
raceinosa in the swamp. Around the shores of the Great Salt Lake
the Rhizophoras and the Avicennias are, however, the most frequent,
sometimes the one, sometimes the other, usurping the lake's margins.
All three mangroves thrive in the creek which leads from the beach
to the lake. In the smaller lagoons, w^here the water has been
reduced to a depth of a few inches and has a greater salinity, the
Rhizophoras disappear from the mangrove belt, leaving the Avicen-
nias and Laguncularias in possession of the borders of the partially
desiccated lake. On the expanse of exposed mud-flats Salicornias
and Batis maritima thrive. When the w^ater has evaporated away
and only a shallow depression indicates the original lagoon, the
Laguncularias in their turn disappear, and Avicennias with Salicornias
and Batis maritima alone remain.

Avicennias grow in this district under all the various soil-conditions
that are presented, whether in the salt-water swamp, in the wet salt

RHIZOPHORA MANGLE

109

mud on the margins of the lagoons, in the places removed from the
lagoons where the saline mud dries on the surface in the sun, in the
neutral ground between the sandy beach and the mud-flat where the
soil is loamy and beach plants mingle with those of the mud-flats,
or, lastly, on the borders of the great inland fresh-water swamps,
where they come in touch with the plants of the Great Morass. In
all these stations they have different associates : herding at one time
with Rhizophoras and Laguncularias in the swamps; at another
growing with Salicornias on the soft mud-flats; at another with
Jacquinia armillaris, Conocarpus erectus, etc., where the saline mud
hardens on the surface in the sun ; at another time side by side with
beach plants like Coccoloba uvifera, Dodoncea hurmanni, and Ernodea
littoralis, where the soil is loamy near the beach; and at another
time amidst the tall Sabal palms (*S. umbraculifera) and the CyperacecB
which mark the outskirts of the inland region of fresh- water swamps.
If we except Conocarpus erectus, there is no plant in the Salt Lake
district that displays so much adaptability to the various conditions
as Avicennia nitida.

Conocarpus erectus is similarly associated here with the mangroves
at the borders of the lagoons, with the plants of the exposed mud-
flats, and with those of the sandy beach ; but its powers of adaptation
are not so conspicuous on account of its being much less frequent
than Avicennia nitida. Its adaptability to different stations is
discussed more in detail in the separate treatment of the plant.

Several other plants occur in this district, but they are usually
not common enough to give character to the vegetation. One may
refer, however, to the Silver Thatch palm (Thrinax argentea), sl small
palm, three to nine feet high, which is certainly characteristic of the
neutral ground between the mud-flats and the sandy beach on the
seaward side and the inland swamps in their rear. Portulaca hali-
moides, an interesting little plant with woolly flowers and only two
or three inches high, grows in places on the salt white mud, especially
where the ground, though moist beneath, is baked on the surface by
the sun's heat. Jacquinia armillaris (L.) is a small tree or shrub
that is very common on the saline mud of the flats, growing gregari-
ously and exhaling from its flowers a penetrating odour like that of
bitter almonds. This is J. barbasco of Mez (Das Pflanzenreich,
Theophrastacece, 1903). It is a littoral plant widely spread in the
West Indies. Its hard seeds, which are 5 mm. in length, have no
buoyancy, and are probably dispersed by birds, though the dryish
berry would not seem to be especially attractive.

Summary

1. As supplementing his observations on Rhizophora in the Pacific
islands, the author adduces additional facts from other sources to
confirm his previous conclusion that the lapse of a period of nine or
ten months between fertilisation and the fall of the seedling is typical
of the genus (p. 96).

2. He presents data from his West Indian experiments to show that
Rhizophora seedlings, after detachment from the tree, can at times

110 PLANTS, SEEDS, AND CURRENTS

retain their vitality in the dry condition for five months, an impHca-
tion arising from his results being that the seedlings, when they fall
into the sea, would often continue their hypocotylar growth in length
for an inch or two (pp. 96-98). His observations in the Pacific on
the proportion of germinating fruits of Rhizophora mangle possessing
more than one seedling, and on the extreme length of the hypocotyl,
are here supplemented (pp. 98-99).

3. He was unable to discover in the West Indies any persistent
evidence of the dimorphism observed by him in Rhizophora mangle
in Ecuador, nor did he come upon any seedless form of Rhizophora
corresponding to the " Selala " of Fiji (p. 99).

4. There are next given the results of a number of observations
made in the West Indies, Ecuador and the Pacific islands on the
influence of varying degrees of salinity on the station of Rhizophora
mangle (pp. 99-101).

5. Remarks arc then made on the infiltration of sea- water into the
interior of the Great Morass of the Black River district in Jamaica,
and in this connection is noted the occurrence of colonies of Rhizophora
mangle in the midst of this great swamp (pp. 101-102).

6. The underflow of sea-water up tropical estuaries is regarded as
an important factor in determining the stations of estuarine plants,
and the subject is illustrated by the cases of the Black River in
Jamaica and of the Guayas or Guayaquil River in Ecuador (p. 102).
In this matter Prof. Harshberger's hydrometric and thermometric
observations on the stations of plants in the tidal estuaries of New
Jersey afford instructive lessons for similar investigations in tropical
estuaries (pp. 103-104).

7. Attention is directed to the numerous large fresh-water springs
that well up in the midst of the Black River Morass, and to the rich
growth of aquatic plants at their borders (p. 104).

8. The author then deals at length with the vegetation of the
Black River district, especially of the Great Morass, as well as of the
similar region of swamp around Savanna-la-mar (p. 105). He also
describes the vegetation of the Great Lake at Pondside near the
Black River (p. 107). The physical and botanical features of the
Salt Lakes in the same neighbourhood are treated in detail (p. 107).

CHAPTER VI

THE LARGER FOREIGN DRIFT OF THE TURKS ISLANDS

In Chapter I. special prominence is given to the analysis of the
larger foreign drift of the Turks Islands. It is now proposed to deal
with each plant in the order of frequency of their fruits or seeds in
the stranded drift of this small group, the several plants being treated
often at length, from the standpoint of distribution. This will
afford an opportunity of discussing the various interesting problems
which these plants raise.

ECASTAPHYLLUM (?)

These legumes, which are amongst the most frequent of the fruits
in the larger drift of the Turks Islands, have some of the characters
of those of Ecastaphyllum, but are certainly not those of E. hrownei
(Pers.), a common West Indian littoral small tree or shrub. They are
IJ-lf inch long, broadly oval, compressed, and have a shining
reticulate epidermis. The single seed has thin, pervious coverings ;
but in no case did I come upon one that was sound, all of them being
in various stages of decay.

Spondias lutea, Linn. (Hog Plum)

Few fruits are more frequently represented in the beach-drift of
the West Indies and of the Pacific and Atlantic coasts of tropical
America than those of this tree. It is not, however, the fleshy drupe
but its hard "stone" invested by a thick fibro-suberous covering,
that is here found. These " stones," which are oblong in form and
usually 1-1 J inch in length, float very buoyantly, and in their weather-
beaten condition amongst old drift might be even taken for old
corks rounded by the waves.

The trees grow in open wooded districts, both inland and at the
coast, and not uncommonly they are frequent at the riverside, as
in the case of the Black River in Jamaica, or they grow in numbers
on the slopes of a river valley, as I noticed in Tobago, or they may
be found amongst the vegetation bordering the beach, as I observed
in Grenada and Trinidad. Writing of the tree in Jamaica at the end
of the seventeenth century, Sloane says that it was found every-
where in the lowland woods and in the savannahs (II., 127). In
Jamaica it is associated in the open inland woods with such trees
as Cedrela odorata (Jamaican cedar), Pithecolobium filici folium

111

112

PLANTS, SEEDS, AND CURRENTS

(bastard tamarind), and Swietenia mahogani (mahogany), and in
Cuba it has the same associates in the open forests that grade into
the savannah formation. But in Cuba it also grows in the denser
forests on the slopes of the river valleys (Fernow, etc., quoted by
Harshberger, pp. 675, 676).

The fruit, however, is too coarse to be palatable for man, but it
is much appreciated by pigs, and from this circumstance it derives
its popular name. As the fallen fruits lie on the ground they lose
their fleshy covering; and the air-dried " stones " are so light that
in places where the trees abound they may be seen gathered together
by the strong winds. On a hillside in Tobago during the heavy rains
I noticed that the " stones," which lay in quantities on the ground,
were being gradually washed down the slope into the river below.
The " stone " usually displays four or five cavities, each containing a
seed. The seeds retain their freshness for years in my drift-collection,
and this is evidently true of those in the beach-drift. However
weather-beaten their appearance, it was never difficult to find
" stones " containing some sound seeds in the old drift, whether on
a beach in Jamaica, where the trees are abundant, or on the shores
of the Turks Islands, where they do not grow.

On account of their great buoyancy the " stones " at first appear
well suited for transport across the Atlantic. But the fact that I
had found no record of their occurrence amongst West Indian drift
stranded on European beaches led me to investigate the matter.
As a result, I found that their floating powers were insufficient for
the purpose of an Atlantic traverse in the Gulf Stream drift. In
addition, it proved to be more than doubtful whether the seeds would
retain their germinative powers after a flotation of more than a few
months. I made an experiment on a number of drift specimens
that preserved their sound condition. The indications were that
although about half still floated after seven months in sea-water,
they were sodden through their substance, floated heavily, and had
decaying seeds. The limit of the period during which the germinative
capacity is preserved in a passage across the sea seemed to be two
or three months. Although the " stones " would be unable to
survive the long passage of a year or more that would be involved in
an Atlantic traverse from the West Indies in the Gulf Stream drift,
they would, as far as their buoyancy is concerned, be well able to
perform the passage of two or three months from the West Coast of
Africa to Brazil in the Main Equatorial Current, and the seeds would
probably retain their germinative powers.

In the Turks Islands the " stones " were to be noticed, often in
numbers, on all the cays where the drift was able to gather. They
presented themselves among the drift on almost every beach in the
West Indies that I examined, as on the north and south coasts of
Jamaica, on the north and south sides of Trinidad, in Tobago, and
in Grenada. It is many years since they were identified at Kew
in a collection of seed-drift made by Morris in Jamaica (Chall. Bot,
IV., 299). They are to be observed in the floating drift of rivers,
as in the Black River of Jamaica, or stranded in numbers at their
mouths, as in the case of the White River of the same island. It is

FOREIGN DRIFT OF THE TURKS ISLANDS 113

on the beaches that hne the coast in the neighbourhood of estuaries
that the " stones " of these fruits arc most abundant.

On the Pacific shores of tropical America they would seem to be
equally abundant, whether afloat in the estuaries or cast up on the
beaches. Thus, I found them in the Guayaquil River in Ecuador
and on the beaches of the Ecuadorian coast towards the Peruvian
border. They came under my notice on the beaches at Panama
and afloat in a neighbouring estuary, and it may be added that they
were gathered by me from the beach at Colon on the Atlantic side
of the isthmus.

The distribution of the tree over the greater part of the West
Indian region, as well as on the Pacific and Atlantic borders of tropical
America, derives new interest from the circumstance that the tree
occurs on the tropical coast of West Africa. As before remarked,
the " stones " are fitted for carriage in the Main Equatorial Current
from West Africa to Brazil, and the seeds would probably preserve
their capacity for germination. The diflficulty, however, is that this
tree is not a truly littoral plant. It may grow amongst the trees
bordering a beach ; but it is more at home in an inland station on a
hillside or near a river bank. It is, in fact, the river that as a rule
brings the floating " stones " down to the coast before giving them
over to the agency of the currents.

Although I have gathered a large number of the stranded " stones "
on beaches, I have never found one showing germinating seeds. In
such an event, however, the young plant would certainly fail to
establish itself. The " stones " are so extremely light that, as I have
observed in the Turks Islands, the strong winds are able to blow them
off the beach into the bush behind, where more favourable conditions
might be found, though not in this particular group. Land crabs,
also, that frequent the beach, might often carry them off and bury
them in their burrows.

It is likely that the spread of this tree within the same land area
is assisted by the facility with which it roots when stakes are placed
in the ground. The wood is very light, and it is possible that the
trunk or a branch floating in a river may on stranding be able to
establish itself on the bank. Sloane observes that it " grows easily
by the branch " (II., 127). Under the head of Growiiig Stakes or Live
Fences in Jamaica, this tree is mentioned in association with several
others in Note 31 of the Appendix to my book on Seeds and Fruits.

HiPPOMANE MANCiNELLA, L. (Manchinecl)

Few plants seem to be better fitted for dispersal by currents than
this littoral tree, which is widely spread over the tropics of the New
World, occurring not only throughout the West Indies and on the
Atlantic coasts of the mainland from Mexico to Venezuela, but also
on the Pacific side.

Pax, in his recent memoir on the section of the Euphorbiacece, to
which this plant belongs {Euphorbiacece-Hippomaiiece, Das Pflan-
zenreich, IV., 147, V., 1912), only implies its occurrence on the Pacific
side in the case of Costa Rica ; but doubtless he includes both coasts
I

114 PLANTS, SEEDS, AND CURRENTS

of Mexico in his statement of the general distribution. Harshberger
(p. 229) merely names Mexico, Central, and South America, without
particularising the Pacific coast. However, I found it growing at
Panama by the beach, and in all probability it is common on many
parts of the Pacific coasts of Central America. Grisebach mentions
Panama, but without distinguishing locality. It is a native of most
of the West Indian islands, large and small, from Cuba to Trinidad,
as enumerated by Grisebach and Pax. It extends north to South
Florida and to the adjacent islands of the Bahamas, such as Andros
and Abaco (Millspaugh), and reaches Venezuela to the south. As
Pax suggests, its absence from certain localities may be due to its
extermination on account of its poisonous nature.

A few remarks on its station may now be made. Wherever I
came upon it, as at St. Croix, Tobago, Grenada, and Panama, it was
growing with the trees bordering the beach on sandy soil. Grisebach
only refers to its station in the case of Trinidad, where it grows " on
the sandy sea coast." Pax characterises it as a plant of the coast-
lands and as often growing on rocky ground. Millspaugh says that
it grows in coppices and on scrubland in the Bahamas. In South
Florida, according to Harshberger (p. 230), it grows away from the
coast, being one of the trees of the " hammocks." This is the name
given to isolated patches of vegetation of varying extent that are
scattered as islands in the everglades and pine forests, and are held
to represent an ancient system of sea-washed keys, which existed
during the later Tertiary and received their plants from the Bahamas.
The " hammock," as we learn, is a refuge for nearly all the flowering
plants that are common to the West Indies and the North American
mainland. Though most of the trees and shrubs named by Harsh-
berger grow in the coastal plains of the West Indies, few seem to be
characteristic littoral plants; and for this reason the hammock
scarcely appears to have become a sanctuary for typical strand
plants in any number.

The very poisonous nature of the milk-sap is well known; yet
it is observed by Pax that some men possess an immunity in this
respect. When at Panama I experienced severe pain for several
hours through allowing the sap of the fruits to come in contact with
my bare legs, extensive blistering resulting. It is probable that
there is a substratum of truth in the fable that fatal effects arise from
sleeping under the shade of this tree. The experiment made in the
West Indies by Jacquin, who remained unhurt after standing naked
for some hours under a tree, whilst the rain fell through upon him
(Hooker's edition of the System of Botany of Le Maout and Decaisne,
1873, p. 697) scarcely seems conclusive. The night dew dropping
slowly from the leaves would be much more likely than the rain- wash
to produce injurious effects.

I made the acquaintance of this tree in different islands, as in
St. Croix, Grenada and Tobago. I did not find it in the Turks Islands,
although, according to Dr. Millspaugh, it has been collected there
(see reference in the chapter on the flora of this small group). Its
place is taken on Grand Turk by a small euphorbiaceous tree or
shrub, not unlike it in habit, perhaps a species of Sapium, which has

FOREIGN DRIFT OF THE TURKS ISLANDS 115

the same popular name, and possesses, according to the inhabitants,
the same dangerous quahtics. The absence from the Turks Islands
of the true Manchineel could scarcely be attributed to its extermina-
tion by the islanders in the isolated uninhabited cays. Although it
grows in Key West, off the Florida coast (Pax), we learn from Dr.
Millspaugh's paper before quoted that it was not discovered by
Mr. Lansing during his methodical examination of all the sand keys
lying west of that island. The vegetation there is mainly littoral,
and in many islets it is exclusively so. Several of the keys are little
more than sandbanks, and the question of extermination by man
could not be raised. It would thus appear that although, as shown
below, the fruits of the Manchineel must be amongst the drift first
stranded on new land in this part of the world, the tree is one of the
last to establish itself. I never remember to have come upon a
germinating fruit in the beach-drift of any locality, although examina-
tion always showed that some of the seeds were sound. It may be
that the intervention of certain land crabs is necessary, and that
germination only occurs after the fruit has been stored in their burrows
beyond the reach of the sea. Sloane, in the account of his voyage to
Jamaica (II., pp. 4, 7), throws some light on this point. He says that
goats feed on the fallen fruit greedily, and he was shown trees that
had grown from seeds dropped in their dung.

I come now to discuss more in detail the fitness of these fruits
for dispersal by the currents. (I may add here that the fruits are
illustrated in the memoir of Pax before named.) On account of
the station of the tree by the beach, the fallen fruits, as I had several
opportunities of observing, are liable to be picked up by the waves
and carried out to sea. Should the fresh fruit, which is rather like
a crab-apple in size and appearance, fall at once into the water,
experiments show that it will remain afloat. But more often it loses
its soft outer covering whilst lying on the sandy soil ; and in so doing
its buoyant capacity is greatly increased. The bared fruit gathered
after drying on the ground consists of a hard " stone " deeply grooved
and covered with a thick layer of cork-like, air-bearing tissue. Neither
the " stones " nor the seeds inside have floating power, the buoy-
ancy being due to the investing material. These dry, bared fruits
evidently can float for many months. Some of them kept in sea-
water for five weeks showed no signs of sinking, all of them floating
as buoyantly as when the experiment began. The stone usually
has about six loculi, but not more than half contain sound seeds,
the others being much contracted in size. Locked up within the
woody endocarp, the oily seeds maintain a moist condition for years.
After eight years, the seeds of some fruits gathered by me at Panama
seemed quite fresh; whilst the fruits of the Turks Islands beach
drift, which may in some cases have been lying there for years, as
a rule appeared sound.

It is, therefore, not surprising that the stranded fruits of the
Manchineel came under my notice in nearly every place where the
beach drift was systematically examined. At Panama, in Jamaica,
St. Croix, Tobago, Grenada, Trinidad, and in the Turks Islands these
fruits formed a regular constituent of the drift, and often in numbers.

116 PLANTS, SEEDS, AND CURRENTS

In several cases the tree was growing in the vicinity, but in Jamaica,
though the bared fruits were to be frequently observed on the beaches,
I never came upon the tree, though, according to Grisebach and Pax,
it exists in the island. In the Turks Islands, as before remarked,
the tree does not grow, yet the fruits occurred on almost every beach,
and made up quite 10 per cent, of the larger drift. Wherever in
this locality the drift had been able to gather, some of them were
to be found, whether on Grand Turk and Greater Sand Cay, lying
at the north and south extremes, or at Eastern Cay, the most wind-
ward island of the group. As far as I can ascertain, these fruits have
not been recorded amongst the West Indian drift stranded on the
shores of Europe ; but it seems highly probable that they sometimes
reach those coasts.

Terminalia catappa, L.

Since this tree was originally introduced into the New World,
I need only refer to the fact that its dispersal by currents has long been
known in the tropics of the eastern hemisphere, where it frequents
the coasts, both insular and continental. In the writings of Schimper,
Hemsley, Ernst, and others (including, I may venture to add, my
own), it is frequently referred to in this connection. We learn from
the observations of Treub, Penzig, Ernst, and their associates that
its drupaceous fruits were amongst the first stranded on Krakatau
after the desolation of its surface by the eruption of 1883, and that
its young trees were amongst the earliest to establish themselves
near the beach.

In the warm regions of the New World it is now widely distributed,
a work originally begun by man but since extended by the currents,
especially in those localities, as in the island of Grenada and at
Colon, where it has resumed its littoral station. In Grenada I found
it bordering the beach in the company of Coccoloba uvifera. Hippo-
mane mancinella, and Hibiscus tiliaceus. According to the data given
by Harshberger, in his work on North America (p. 686), it grows
characteristically among the trees lining the beach in the Virgin
Islands in association with Coccoloba uvifera, Hippomane mancinella,
Thespesia populnea, etc.

Its fruits came under my notice in the beach-drift of Jamaica,
Colon, and the Turks Islands. In the last-named locality they are
abundant and occur on almost every beach where drift collects,
always bared of their outer fleshy covering, and nearly always in a
much weathered condition, but in most cases containing a sound
seed. As is well described by Schimper in his Indo-Malayische
Strandflora (p. 170), this drupaceous fruit owes its floating powers
to a thick layer of cork-like buoyant tissue that invests the " stone,"
none of the other materials possessing independent buoyancy.
The subject of the floating capacity of the fruits of the genus is fully
discussed in my work on Plant Dispersal.

Although Grisebach, Hemsley and other authorities agree in regard-
ing this tree as introduced into the New World, it is remarkable
that about a third of the total number of species in the genus, as
indicated in the Index Kewensis (132 in all), are confined to America,

FOREIGN DRIFT OF THE TURKS ISLANDS 117

of which by far the greater number are tropical South American.
But the endemism displayed in oceanic islands in the Indian and
Pacific oceans, as well as in the West Indian islands, is very remark-
able. The Mascarene Islands, Mauritius, the Andaman and Nicobar
groups, the Fijian, Samoan, and Tongan archipelagos, Cuba, Jamaica,
and even the Bahamas (Harshberger, p. 330), all hold one or two
peculiar species of Terminalia. If we were to look for the home of
Terrninalia catappa in a region where the genus is best represented,
we should find it in the New World, particularly in South America.
The New World, we might imagine, ought to have been able to
provide its own wide-ranging littoral species; and it seems strange
that human agency should have had to intervene in the matter.
However, the distribution of the genus presents many problems
that cannot be dealt with here.

Entada scandens, Benth.

This plant is discussed at length in my two books. Plant Dispersal
and Studies in Seeds and Fruits. In the first named it is regarded
from the distribution standpoint. In the second, the germination
process, the various stages in the maturation of the seed, and the
development of its impermeability, are dealt with in much detail.

The great floating powers of the seed have long been known, as
well as its ability to retain its germinative capacity after being
stranded on the European side of the Atlantic. The white, softish,
full-sized moist seeds of the green legume possess no buoyancy. This
capacity is acquired during the shrinking and hardening stage, being
due to the large cavity produced by the bending outwards of the
cotyledons as they dry, the materials of the typical dry seed having
no floating power.

The initial buoyancy of the seeds when recently detached from the
plant is indicated by the results of experiments made in Fiji and
Ecuador (Plant Dispersal, p. 181), from which it is inferred that
quite 50 per cent, sink in sea-water and about 70 per cent, in fresh-
water. In a recent experiment made in Jamaica the proportion of
non-buoyant seeds in freshly gathered material was much smaller,
only 20 per cent, sinking in sea- water and 30 per cent, in fresh- water.
This variation in the initial buoyancy is due to the variation of the
conditions attending the shrinking and drying process, which would
probably be less complete in shady humid forests than in drier,
exposed situations. From curiosity I tested the buoyancy of a
hundred seeds with sound coverings that had been brought by
currents and stranded on the Turks Islands. Of these, all but five
floated in fresh-water and all but one in sea-water, the last named
having from some cause lost its buoyancy. In my previous work
on Seeds and Fruits it is shown that loss of impermeability may in
time be induced through some initial defect in the cuticle.

The seeds form a frequent constituent of beach-drift in the warm
regions of the New World. Amongst localities in which I found them
may be mentioned Ecuador, both sides of the Isthmus of Panama,
Jamaica, and the Turks Islands, but not in Trinidad, Tobago, or

118 PLANTS, SEEDS, AND CURRENTS

Grenada, for reasons given below. In Jamaica I found them at
various places, but only on the north coasts; but since they were
obtained by Morris amongst the stranded drift near Kingston, it is
evident that they may also be thrown up on the south side (ChalL
Bot., IV., 302). In the Turks Islands they were frequent on every
beach that held drift.

The distribution of the plant in the New World is peculiar. It is
found in Jamaica and probably also in Cuba, Haiti, and Porto Rico,
and occurs on both coasts of Central America. But it is absent from
the Bahamas, and though existing in the northern islands of the
Lesser Antilles, as in Guadeloupe, it has not been recorded from the
southern islands and from Trinidad. The implication of the absence
of its seeds from the beach-drift of Trinidad and the adjacent islands
off the Spanish Main is that it is not to be found in the neighbouring
portion of the South American continent, that is to say, in the regions
drained by the Orinoco and the large rivers of the Guianas. In these
continental regions its place, though not its station, is taken by two
or three other species.

Of these, probably the most typical is Entada polystachya, a plant
which I have discussed at length from a particular standpoint in
my Studies in Seeds and Fruits. This species, which has much
smaller non-buoyant seeds, has its home, according to Grisebach, in
the Lesser Antilles from Dominica to Trinidad, as well as on the
adjacent South American mainland, and, strangely enough, also in
Panama. It grows away from the beach and often on trees by
the side of rivers. It is not represented in the beach-drift, its
seeds possessing no floating power, and evidently it could only be
dispersed by currents through the agency of the separate joints
into which the pod breaks up, the buoyancy of which could not be
great.

With regard to the absence of Entada scandens from Trinidad and
the neighbouring islands of Tobago and Grenada, I may say that it
is not represented in Hart's Herbarium List for Trinidad. Mr. Broad-
way, who had an experience covering several years of the flora of
this region of the West Indies, told me that it has not been found
there. The only localities given by Grisebach are Guadeloupe and
Jamaica, but the presence of its seeds in such quantities on the
Turks Islands beaches indicates that it must be at home in San
Domingo and Porto Rico, from which the seeds are in all probability
derived. Its seeds occur in the drift on both sides of the Isthmus
of Panama and on the beaches of Ecuador, and the plants grow in
the woods at the back of the coasts in those regions.

Grisebach, when referring to the station of Entada scandens in
Jamaica, says that it is common in mountain woods; and it was
usually in that station that I found it. But it may survive on trees
beside streams and ditches in districts where the woods have long
since been mostly cleared away for cultivation, as at Moneague. The
greatest altitudes above the sea at which the plant came under my
notice in Jamaica were on the slopes of Mount Diablo at 2000 feet,
at Pallet at nearly 2000 feet, and at New Find near Lumsden at
about 1500 feet — the two last localities being in the mountains at

FOREIGN DRIFT OF THE TURKS ISLANDS 119

the back of St. Anne's. In the Pacific Islands it is a characteristic
plant on the trees lining the beaches and the estuaries.

Two critical facts present themselves in the New World with
reference to the distribution of this plant over the warm region of
the globe. In the first place there is its occurrence on both the
Atlantic and Pacific borders of Central America. As I pointed out
in my work on Plant Dispersal, this does not compel us to assume,
as in the case of the mangrove flora, that the plant's present distribu-
tion in the New World antedates the emergence of the Panama
Isthmus. Frequenting, as it does, not only estuarine regions but
also mountain woods inland, it can be at once perceived that, given
its occurrence in the interior of a region like the Isthmus of Panama,
the seeds of plants growing on the same " divide " could be carried
by rivers to both the Atlantic and Pacific borders. The seeds are
often found in river-drift in different parts of the world. Thus I
found them not only in estuaries on both sides of the Panama Isthmus,
but also in the Guayaquil River in Ecuador, and in the estuaries
of Fiji.

The second critical fact of distribution is that whilst Entada
scandens grows on the West Coast of tropical Africa, it is absent from
the corresponding portions of South America (Venezuela to Brazil)
and from the neighbouring West Indian islands, such as Trinidad
and Tobago. It is certainly strange that seeds, which are trans-
ported in the Gulf Stream drift to Europe in a sound state, have
not been carried by the Main Equatorial Current from the Gulf of
Guinea to the South American mainland. As described in Chapter III.,
this is the direct track of many of the bottles thrown overboard in
this current in mid-Atlantic. Whilst a West Indian seed would
require a year or more to reach the coasts of Europe, it would accom-
plish the passage from West Africa to Brazil in the Main Equatorial
Current in from two to three months. A great deal, of course,
depends on the distribution of the plant on the African coast. If it
does not grow much south of Senegal and the Gambia, its seeds would
be carried across the Atlantic in the North Equatorial Current,
and would not strike the South American mainland. It is pointed
out in Chapter III that bottle-drift from the latitude of Cape Verde
only reaches the Lesser Antilles and the islands north; and it is
not improbable that we have here an explanation of the peculiar
distribution of Entada scandens in the New World. In other words,
its range in tropical America may prove to be determined through
the arrangement of the equatorial currents by its distribution in
tropical West Africa.

It may be that E7itada scandens has not been for many ages a
denizen of the New World. So little does it figure in the floras of
the larger West Indian islands that the American botanical explorers,
so freely quoted in Harshberger's great work, rarely seem to have
recorded it. Yet it probably occurs in all these large islands. It is
almost certain that the numbers of these seeds thrown up on the
beaches of the Turks Islands are derived from Hispaniola, Porto
Rico, and the northern islands of the Lesser Antilles, since the
plant is not represented either in the drift or in the floras of the

120 PLANTS, SEEDS, AND CURRENTS

southernmost islands and of the adjacent continental regions of
South America (Venezuela to Brazil).

Yet a different standpoint may be needed when we come to regard
the distribution of the genus. About a score of species are kno's\Ti,
of which about a fourth are confined to the New World and about
two-thirds to Africa and Madagascar, whilst Burma holds a species of
its own. The indications are that, as a genus, Entada belongs to
the tropics of both the eastern and western hemispheres, and that,
however effective oceanic currents may have been in dispersing
a particular species {E. scandens) around the globe, we must look
elsewhere for the explanation of the range of the genus. In this
respect Entada falls into line with a multitude of tropical genera
shared by the Old and the New World.

A word may be said here respecting the spread of Entada scandens
to the interior of continents, as, for instance, to the Himalayan
region and to the lake district of Africa. It is quite likely that man
has often here played a part, but it is probable that large animals
have also taken a share in the dispersal. We know that camels
and ostriches ^^ill at times swallow almost anything; and although
such creatures would scarcely frequent localities where Entada
scandens is at home, yet it is noteworthy that there is in the Kew
Museum an entire seed of this plant, measuring about 1 J inches across,
which was removed from the caecum of a rhinoceros from Chittagong
that died in the Zoological Gardens of London.

MUCUXA URENS, DC, AND AX ALLIED SPECIES, PROBABLY MUCUNA
ALTISSIMA, DC.

Mucuna seeds of two kinds, not very dissimilar in appearance and
evidently belonging to allied species, make up 6 per cent, of the larger
drift cast up on the beaches of the Turks Islands. Of these about a
third belong to M. urens, DC. and are not to be distinguished from
seeds of the same species collected by me in the Pacific islands (Plant
Dispersal, p. 80, etc.). The plant in flower and fruit, as observed
by me in Jamaica and Tobago, corresponds to De Candolle's descrip-
tion as given by Grisebach ; whilst seeds of the same species gathered
by me on the Panama beaches were thus named at Kew. The seeds
are semi-globose, nearly an inch across (20-24 mm.), and have a
broad raphe, a fifth of an inch (5 mm.) wide, that nearly encircles the
seed. They are typically greyish black or brownish black, but seeds
in the drift may present a lighter hue. The other Mucuna seeds
belong to a type often designated as " near urens " in this work.
There are reasons for the belief that they are the seeds of M. altissimay
DC, a species regarded as confined to the New World, and as such
they are sometimes referred to in these pages ; but, as shown below,
this identification requires confirmation. These seeds are twice as
frequent as those of M. urens on the beaches of the Turks Islands.
They are flatter or more depressed and are rather over an inch in
diameter (20-30 mm.), and they possess a narrower but similarly
encircling raphe (3-4 mm.). In colour they are usually a dark or a
light brown, and when of the lighter hue they sometimes display

FOREIGN DRIFT OF THE TURKS ISLANDS 121

black mottlings. The distinctions, however, especially as regards
the width of the raphe in the two species, sometimes disappear.
One finds at times drift seeds that might be referred to either kind,
and even the seeds of growing Jamaican plants of M. urens were
not always constant in their characters.

Bentham, when describing Mucuna altissima in the Flora Brasi-
liensis (Mart. XV., part 1, p. 169, tab. 46, 1859-62), remarks that the
fruit is unknown; but he figures with a query under this name a
pod with seeds that are very like those designated " near urens "
in these pages. Grisebach (1864) describes the legume and seeds of
this species. The last are stated to be orbicular, compressed, eight to
ten-tenths of an inch in diameter, and almost wholly surrounded by
the raphe, a description, which, except for the smaller size, would
apply to the drift seeds of the " near urens " type. The last are
stated above to be rather over an inch across. The matter, how-
ever, requires further investigation.

Authorities are agreed that Mucuna urens is widely spread in the
tropics of the Old and New World. In the latter it occurs in all the
larger as well as in many of the smaller West Indian islands, and
extends south to Peru and Brazil on the Pacific and Atlantic sea
borders. There has been apparently some uncertainty about the
limits of the species in the Old World, but there is no doubt that it
is found in tropical West Africa as well as in the Pacific islands
(Hawaii, Marquesas, Samoa) and in other regions. Mucuna altis-
sima, to which the seeds of the other kind probably belong, is, accord-
ing to Grisebach, a peculiar American species distributed over the
West Indies and occurring on Central America and in Brazil.

The same two kinds of Mucuna seeds also came under my notice
frequently in the beach-drift of other parts of the West Indies besides
the Turks Islands — namely, in Trinidad, Tobago, Grenada, and in
Jamaica ; and in their association they are evidently very character-
istic of West Indian drift. On the beaches of Tobago and Trinidad,
where they are numerous and often encrusted with Balani, they occur
in nearly equal numbers. As far as I could judge from the Morris
collection of Jamaican beach-drift in the Kew Museum, the same two
sorts of Mucuna seeds are there represented under the name of
M, urens. As occurring in West Indian drift the seeds of both sorts
are usually sound and germinable. They are those that are trans-
ported across the Atlantic to Europe in the Gulf Stream drift. It
may be here stated that Ridley, in 1887, found two seeds of Mucuna
urens, D.C., stranded on Fernando Noronha, off the coast of Brazil
{Journ. Linn. Soc, vol. 27). The plant grows on the mainland;
but it is far more probable that the seeds were brought in the Main
Equatorial Current from the Gulf of Guinea.

Peculiar (as far as my experience goes) to the Trinidad and Tobago
beach-drift are the seeds of another species of Mucuna readily recog-
nised by their larger size (IJ-lJ inch, 31-37 mm.), by their flatter
form, and by the great width of the encircling raphe (9 or 10 mm.).
They are greyish or brownish black, usually sound, and to quite half
of them the shells of marine organisms (annelids, cirripedes, etc.)
are attached, an indication of a previous flotation of months in the

122 PLANTS, SEEDS, AND CURRENTS

sea. Since the drift always reaches these islands from the southward
and eastward, it is likely that these seeds were brought by the
Equatorial Current flowing northward along the coasts of Brazil,
and it is not beyond the limits of possibility that they might even
have been brought over from the African coasts.

It is, however, with the two seeds of the urens " type (Mucuna
urens and M. altissima?) that we are here concerned. Singular
confusion has arisen in the application of the specific name of
pruriens DC. to one of these by older as well as recent botanists,
a name which is really that of a very different species of Mucuna,
a weed of cultivation and quite unsuited for distribution by the
currents. The error seems to date far back, perhaps originating with
the interpretation of a remark made by Forster, one of Cook's
botanists ; but the discussion of the matter is reserved for Note 10
of the Appendix. Both of them came under my notice in a sound
condition amongst the West Indian seeds stranded on the Azores.
As in the beach-drift of the Turks Islands, those of the true urens
type were only half as frequent as those of the other species. It is
probable that the drift seeds of this genus which Darwin received
with other drift from the Azores {Chall. Bot., IV., 291) belonged to
these types. Evidently both kinds are often cast up on European
beaches; but it is noteworthy that of the five specimens from those
beaches which I have handled — namely, from the South of England,
Ireland, and the Shetland Islands, four belong to the " near urens "
kind and one to the true urens type. However, both sorts are to be
found amongst the West Indian drift seeds picked up in the South
of England, as contained in the Kew collection.

Ever since Sloane referred, more than two centuries ago, to the
fact that these Mucuna seeds are frequently thrown up on the Orkney
Islands, they have been frequently observed on European coasts,
and they are often mentioned in this connection in Chapter II. On
the Scandinavian beaches they are very commonly noticed according
to Sernander (pp. 119, 143), and have even been found on the Baltic
shores, being alluded to under the name of M. urens, L., DC. Lind-
man, who is there quoted, mentions the seeds of yet another species
of the genus which have been found on Scandinavian beaches. They
are referred with a query to M. macroceratoides, DC. In the Index
Kewensis, M. macroceratides is accredited to Brazil. It was evi-
dently to M. urens that Lyngbye alluded when he identified some
seeds picked up by him on the Faroe Islands in 1817 as belonging to
Dolichos urentis, a matter already mentioned in Chapter II.

The records of these seeds on European beaches are to be found
scattered through Chapter II. In this place they are briefly given
together. Next to the record of their occurrence in the Faroe Islands
we have that for the Shetland Islands. The specimens sent to me
from that group were of the " near urens " type. Mr. Peel refers
to seeds probably of Mucuna urens as amongst the West Indian seeds
thrown up on the outer Hebrides ; and it cannot be doubted that they
frequently reach the west coasts of Scotland. On the Irish coast
they are regular constituents of the West Indian drift there stranded.
For my information relating to this locality I am mainly indebted

FOREIGN DRIFT OF THE TURKS ISLANDS 123

to Miss Knowles. The only Irish seed inspected by me came nearest
to the true urens type.

On the beaches of the South of England Mucuna seeds are occa-
sionally found. In the Kew Museum there is a specimen named
M. urens from Cornwall, and another specimen from the Isle of
Wight is named near M. urens.''' I found a sound seed of the kind
last mentioned on the south coast of Devonshire, and Hemsley names
Mucuna seeds (doubtless of one or other of these two sorts) as picked
up near Portsmouth (Chall. Bot., IV., 291). Many of these seeds found
on European beaches are quite sound. Lindman procured the
germination at Upsala of seeds of M, urens obtained from the Scan-
dinavian beaches (Scrnander, p. 7); and in this connection it is
important to note that seeds gathered by me from the plant in the
Hawaiian islands germinated and gave rise to healthy plants, after
being kept afloat in sea-wa^er for a year {Plant Dispersal, p. 80).

With regard to the buoyancy of the seeds of these two kinds of
Mucuna, their frequent occurrence in beach-drift and their ability to
cross the Atlantic unharmed are facts of observation above recorded.
In my woik on Plant Dispersal (pp. 80, 81, 531, etc.) I deal more
especially with the seeds of M. urens as found in the Pacific islands.
Though, as above observed, seeds remained afloat after a year in sea-
water and subsequently germinated, it was indicated in my experi-
ments that on account of the liability of the seeds to absorb sea- water
and swell in the warmer parts of the ocean, a large proportion, at
least 50 per cent., would sink in the early part of the transatlantic
passage.

As concerns the station of the plants of Mucuna that are most
frequently represented in West Indian beach-drift, I have only
data for M. urens proper ; but doubtless the plants yielding the seeds
of the other kind are similar in their habits. If, as is not unlikely,
the last mentioned prove to be the seeds of M. altissima, DC, then
we are concerned with a species that grows in mountain-woods in
the West Indies and on the tropical American mainland. This
species came under my notice as a tree-climber around the lake of
the Grand Etang in Grenada, but not in seed. M. urens came under
my notice in Jamaica climbing on the trees of the wooded slopes of
the Black River above Lacovia, and also in the " pen " district
around Moneague in the centre of the island, growing on trees by
the side of ditches. I also found it hanging from the trees on the
banks of Les Coteaux River in Tobago. In such stations the seeds
are very likely to fall into streams and rivers, and they may be
observed amongst the drift stranded at the mouths of rivers, as in
the case of the Black River and of the White River in Jamaica. It
is in this manner that the seeds of this plant are generally brought
within the influence of the ocean currents, being first carried down
by rivers from inland regions to the sea.

However, not all the seeds of Mucuna urens that fall into the rivers
reach the sea, since a number of them sink in fresh-water. I did
not test the relative buoyancy in fresh-water of seeds gathered
directly from the plant ; but the seeds of the beach-drift, though they
all float in sea-water, not infrequently sink in fresh-water. Ten

124 PLANTS, SEEDS, AND CURRENTS

per cent, of the seeds of the Turks Islands beach-drift and 20 per cent,
of the drift seeds of Trinidad and Tobago sank in fresh-water. It
may be added that of the seeds of the alHed species (near urens)
found in the beach-drift of the two locahties just named, all floated
in sea-water, but 20 per cent, of those of the Turks Islands and
9 per cent, of those of Trinidad and Tobago had no buoyancy in
fresh-water. In their buoyant behaviour the seeds of these two
kinds of Mucuna, so common in West Indian beach-drift, illustrate
the fine adjustment, referred to on pages 96 and 181 of my work
on Plant Dispersal, that is not infrequently to be observed with the
seeds of leguminous plants dispersed by currents. This principle
would probably be exemplified in a more marked manner by Mucuna
seeds taken direct from the plant, just as has been already described
in the case of Entada scandens. An obvious implication of the
results of these experiments on the relative buoyancy of such seeds
in salt and fresh water is that a good proportion of those found in
beach-drift must have grown on coast trees, since they could not
have been carried down to the sea from inland districts by a river.

In this connection one may add that of the large Mucuna seeds
of the Trinidad and Tobago beach-drift, which are described without
a specific name on page 121, 50 per cent, sank in fresh- water, although
all floated in the sea.

Fevillea cordifolia, SW. (Antidote Vine)

This plant belongs to a cucurbitaceous genus holding about six
species, all of which are tropical American and West Indian. It is
a climber on high trees, and where a river traverses a wooded region
the fruits often fall into its stream. It has a wide distribution in
the West Indies (Cuba, Jamaica, Hispaniola, Porto Rico, Guadeloupe,
Martinique, Trinidad, etc.), and in tropical America.

As in the case of Grias cauliflora (see p. 211) the discussion of its
means of dispersal raises some critical questions relating to their
connection with the area of distribution. Both are restricted to the
tropics of the New World, and both display a general unfitness for
dispersal by currents — an unfitness not concerned so much with
deficiency in the floating power of the seed {Fevillea) or of the fruit
(Grias) as with the loss of the germinative capacity.

I will at first refer to the mode in which the seeds reach the coast in
Jamaica, and then to their condition in the beach-drift, where they occur
in numbers. The station of the plant as a vine on the trees bordering
the Black River is noticed on page 15. The fruit is heavy, rounded,
and four to five inches in diameter ; and since the plant often grows
on the tree-branches spreading over the water the fruits frequently
fall directly into the river. Only a few ripe fruits were to be seen
on the plants when I examined the Black River in January 1907;
but I learned from one of my boatmen, a native of the district,
that the " ploom-ploom," as he termed it, of the fruits as they fall
into the water is commonly to be heard when ascending the river
in March. However, during my ascents I observed both fruits and
seeds afloat in the drift, the last being very frequent.

FOREIGN DRIFT OF THE TURKS ISLANDS 125

The ripe fruit, which usually contains about ten seeds, floats
when it falls into the water. In course of time it breaks down
whilst still at the surface, the seeds escaping and floating away;
its buoyancy being due not only to the seeds but also to the floating
power of the pericarp. The seeds are flat and round and about
two inches across. They are as buoyant in the moist fresh condition
when just freed from the fruit as they are in the dry condition.
The embryo which forms the kernel has no buoyancy, the seed
owing its floating power to the coverings. On first examining it,
the seed would seem to be structurally well equipped for transport
by marine currents. In the moist fresh state, when the embryo or
kernel fills its cavity, the cotyledons are closely appressed; but the
embryo is imbedded in spongy cellular tissue, especially aeriferous in
its outer part and very buoyant. Outside this tissue is a thin crus-
taceous shell, which is non-buoyant, but the seed possesses an outer
border or edging, 4 to 5 mm. thick, of a brownish suber-like material
which is very buoyant. Thus it is that when, as often happens, an
empty seed splits into two halves in the manner below described, the
two portions float away and occur loose in the drift. In the older seeds
found afloat in the river the inner spongy tissue is drier, brownish,
and increased in buoyancy; whilst the floating power of the seed
is sometimes augmented through an empty space in its interior due to
the shrinkage of the embryo.

But there is a weak place in the seed's structure as far as buoyancy
is concerned, since water is apt to penetrate the suture between the
two halves of the crustaceous shell. This might favour the germina-
tion of a seed floating in a river; but it would be fatal to the ger-
minative capacity of a seed floating in the sea. This explains the
condition of the seeds found afloat in the Black River drift, many of
which must have been a long while out of the influence of the current
and doubtless belonged to the previous fruiting season. They were
very frequent in the river-drift in January, and I examined a
considerable number of them from my canoe, with the following
results —

Sound seeds (one or two germinating) 50 per cent.
Seeds injured by boring animals or by

the nibbling of fish . . . 15 ,,
Seeds empty or with decaying embryo 30 ,, ,,
Seeds represented by the two separated

halves of the shell . . . 5 ,, ,,

100

Thus, excellent as the provision for long flotation at first sight
seems to be, it is really very faulty, and it is doubtful whether
effectual over-sea transport is possible for any distance.

Reference will now be made to the testimony of these seeds as
they lie stranded on the Jamaican beaches after being brought
down by the rivers. I especially studied their condition on the
beaches stretching four or five miles on either side of the mouth of

126 PLANTS, SEEDS, AND CURRENTS

the Black River, where they occur in numbers, and obtained these
results —

Fresh-looking seeds with seemingly

sound kernels . . . .10 per cent.

Seeds with decaying kernels . . 20 ,,

Empty seeds . . . . 45 ,, ,,

Seeds represented by the separate

halves of the shell . . . 25 „

100

By comparing the above results with those before given for the
floating drift of the Black River, we see at a glance that the proportion
with sound kernels or embryos has fallen from 50 to 10 per cent.,
which is by no means a promising sign of fitness for ocean transport.

The seeds came also under my notice on the beaches of other
parts of Jamaica, as at St. Anne's Bay and at the mouth of the
White River, but with unsound kernels or merely as empty shells.
It should be mentioned in this connection that Mr. Hemsley, speaking
of the seeds gathered by Mr. Morris on the sea-shore oft Kingston
in the same island, says that they " look quite sound " (Chall. Bot.,
IV., 302). It may, however, be surmised that, as the seeds were
collected for transmission to Kew, only the soundest specimens
would have been selected. Only the empty seeds came under my
notice on the Trinidad beaches, the plant according to Hart's list
growing on the island.

The next stage in the progress of the seeds in crossing the ocean
would be presented in the stranded drift of one of the outlying
groups of the West Indies, where the plant does not grow, as in the
Turks Islands. To reach these islands the seeds would have to
traverse usually some hundreds of miles of sea in their journey by
the prevailing surface drift- currents from the islands to the eastward
and southward. Now the following was the state in which these
seeds presented themselves to me as they lay stranded on the beaches
of the Turks Islands, and their testimony goes to emphasise their
unfitness for ocean transport.

^ Seeds with seemingly sound kernels 5 per cent.
^ Seeds with kernels of doubtful

soundness . . . . . 15 ,, ,,
Seeds with decaying or decayed

kernels . . . . . 30 ,, ,,
Empty seeds. . . . . 30 ,,
Seeds represented by the separated

halves of the shell . . . 20 ,, ,,

100

Similar indications were offered in the results of flotation experi-
ments conducted in England during the summer on seeds that had

^ It is extremely doubtful whether any of the seeds were germmable.

FOREIGN DRIFT OF THE TURKS ISLANDS 127

been taken from the ripe fruit in Jamaica five months before. Of
four placed in fresh-water one sank in three weeks and displayed
on examination a decaying kernel. One sank in seven weeks, and
failed to germinate when placed under suitable conditions, the
embryo proving to be in a putrid condition. Two remained afloat
after two months, and of these one showed a kernel beginning
to decay, whilst in the other it was quite fresh and sound. Of four
put in sea-water at the same time, one sank in three weeks and
another in six weeks, both losing their kernels by decay when sub-
sequently placed in soil. Of two that floated after a couple of
months immersion, one showed a putrid kernel and the other a kernel
in an earlier stage of decay.

The outcome of all these observations on the seeds of Fevillea
cordifolia is that after they have been freed by the breaking down
of the fruit floating in river-drift they will float for a long time un-
harmed in the fresh-water, some of them ultimately germinating
at the surface. Of the numbers that would not be detained in the
river but would be carried down to the sea, most would soon succumb
to the injurious effects of salt water, and probably none would
preserve their germinative capacity after floating for several weeks
in the sea. A scale of progressive deterioration is indicated by my
observations, beginning with those seeds floating in river-drift
where 50 per cent, are sound, then taking those stranded on the
neighbouring sea-shore where 10 per cent, only are sound, and ending
with some sandy islet a few hundred miles away, where only 5 per
cent, would be regarded as sound. Seeds that behave in this fashion
could never cross an ocean unharmed, though it is quite likely that
the empty crustaceous shell, or its separated halves, would be found
amongst the West Indian drift stranded on the coasts of Europe.

Manicaria saccifera

As it is a little doubtful whether one or more species are included
under this name, it is here used in a general sense. The stranded
fruits of these palms came under my notice in widely removed
localities of the West Indies, as in Jamaica, Tobago, Trinidad, and
the Turks Islands, and I may here add Colon. They have long been
known as occurring in the beach-drift of Barbados and of other
islands of the Lesser Antilles, and in recent years they have been
noticed on the Cayman Islands. Yet with the exception of Trinidad,
none of the West Indian islands are known to possess these palms.
The observant Jamaican native when he picks up on the beach the
" sea coco-nut," as he calls it, will tell you that it has been " brought
by the waves from a distance." So also the Barbadians, who name
it " sea- apple," can have no acquaintance with the palm.

The distribution of these palms is very interesting. Though
recorded from the estuaries of tropical South America, as from the
Amazon, the rivers of the Guianas, and the Orinoco, Trinidad repre-
sents its only known insular habitat. Yet the presence of the drift
fruits in such numbers in the Turks Islands at the south-east ex-
tremity of the Bahamas seems to indicate that the palms grow in

128 PLANTS, SEEDS, AND CURRENTS

the estuaries of the large islands to the southward and eastward,
such as Hispaniola and Porto Rico. However, Urban up to recent
times did not know of their existence in those two islands, since he
refers to their fruits as brought from South America to Porto Rico
by the currents (Symbolce Antillance, IV., 131, 1903-11). Writing
about 1885 Hemsley remarked that it is quite possible that these
palms exist in Jamaica {Chall. Bot., IV., 303) ; but Morris a few years
later wrote that on account of their striking appearance and the
peculiarity of their entire leaves these palms, if they existed in the
island, " could not fail to be noticed " {Nature, January 31, 1889).

Manicaria saccifera is essentially a palm of the Amazon estuary,
its native name being Bussii or Ubussu. Spruce tells us that it
abounds on both banks of the Lower Amazon (Notes of a Botanist,
etc., I., 56). Martius, as quoted by Hemsley (Ibid.), writes that it
is abundant on the banks of the Amazon estuaries, but is not known
from the interior of the continent. Bates observed many of the
fruits afloat in the sea about 400 miles off the mouth of the main
estuary of the Amazon, mingled with much drift brought down by
the river {The Naturalist on the River Amazons, 1864, p. 461). The
Ubussu palm, as he also characterises it, is described by him as growing
on land overflowed by the tide in the estuaries of that great river
{Ibid., pp. 69, 139). These palms play the same role in the Lower
Amazon that is taken by Nipa fruticans in the estuaries of tropical
Asia and Malaya.

According to Sloane's Natural History of Jamaica (II., 186) these
fruits in his time (the close of the seventeenth century) were fre-
quently cast up on the Jamaican beaches, and were amongst the
West Indian drift thrown up by the " Currents and Seas " on " the
north-west islands of Scotland." He refers to Petiver's description
and figure in his Gazophylacium Naturce (tab. 64, fig. 3, p. 6), where
it is mentioned as a fruit " from about Cartagena in America."
Hemsley quotes Sloane in this connection {Chall. Bot., IV., 303),
and reference for further particulars should be made to his pages.

Doubtless the fruits of this palm have since been often found on
European coasts, but seemingly they have rarely been identified.
There is but little ground for believing that the drifting fruits ever
retain the germinative capacity when stranded on the shores of
Europe. I became very familiar with these drift fruits in various
localities of the West Indies, widely removed from each other, and
formed the conclusion that, as far as concerns the disposal of the
species, the floating fruit would be quite ineffective except in the case
of very short sea traverses.

The fruit is one to three lobed, and has an outer almost woody
warty or tuberculate covering, rudely suggestive of some coniferous
fruit, a covering that is soon lost in the drift. Plukenet's description,
as quoted by Hemsley {Ibid.), of the fruit cast up on the coasts of
Barbados — -fructum externo cortice denudatum — is true of the great
majority of the stranded fruits on West Indian beaches, and would
apply to all fruits stranded on the shores of Europe. But at times,
as on Jamaican beaches, and on very rare occasions in the Turks
Islands, one finds a fruit with its " cortex " more or less intact.

FOREIGN DRIFT OF THE TURKS ISLANDS 129

Plukenet states that Sloane showed him specimens obtained from
Jamaica that retained this outer case. I find it difficult to beUeve that
such fruits did not reach Jamaica from some source nearer than
Trinidad and the Orinoco and Amazon regions. I only found the
fruits retaining the " cortex " on the north side of the island, and it
will be pointed out below that it is just on these northern Jamaican
beaches that these drift fruits are most numerous and most likely
to be at all fresh. The foreign drift on the north coast of Jamaica
must be mainly Cuban and Haitian; whilst that on the south coast
would be largely brought by the Equatorial Current from Trinidad
and the adjoining estuary of the Orinoco, as well as from the Amazon
estuaries further south.

On Trinidad, where these palms grow in the swamps, and on the
neighbouring island of Tobago, the entire fruits are frequently found
in the beach-drift, where they are mingled with others that have
lost the outer coverings, and have in some cases come from a great
distance, since not a few are incrusted with Balani and similar
marine organisms.

Within the common casing are usually two or three (at times
only one) globular fruits of the size of a small apple and covered
by a hard thin shell, which is somewhat brittle and more or less
adherent to the indurated skin of the kernel. The albumen lines
a large cavity, as in the coco-nut, and it is to this cavity that the
fruit's buoyancy is entirely due. It is the bared globular fruit that
is characteristic of beach-drift over much of the West Indian region.
Very rarely does one come upon a fruit that is seemingly " germinable,"
and then, as a rule, only in the vicinity of its home. In Jamaica, where
the fruits are more numerous on the northern than on the southern
beaches (probably in the first case largely derived from Cuba or
Haiti, and in the last case cast up by the Equatorial Current), it is
very difficult to find a fruit that could be characterised as sound,
and when one is found it is on the north coast. Around the districts
of Black River and Savanna-la-mar, on the south-west coasts, all
examined had mouldy or unhealthy kernels with embryos gone or
in a decaying state. On the north coast, as around St. Anne's Bay
and its vicinity, I found that about 20 per cent, were rotting inside,
and about 60 per cent, displayed sour-smelling, mouldy kernels and
decaying embryos. The remainder were fairly healthy, but the
embryos were excessively shrunken, and the albumen was usually
hard and dry ; but in a few cases the contents were fresh and relatively
moist and the embryo was healthy, water still remaining in the
seed cavity.

It is noteworthy in this connection that the fruits collected by
Morris amongst the beach-drift off Kingston on the south side of
Jamaica were found at Kew to possess unsound seeds (CkalL Bot.,
IV., 303). This is the rule in Jamaica. On the other hand, in an
island like Trinidad, where the palm is at home in the coast swamps,
fresh fruits are frequent among the stranded drift, 50 per cent, of
those observed by me being sound. However, some of these fresh
fruits may be derived from a source near at hand, namely, the
estuary of the Orinoco. In Tobago, only twenty miles distant from

K

130

PLANTS, SEEDS, AND CURRENTS

Trinidad, the proportion of sound fruits in the beach-drift is nearly
as large. This island is not known to possess the palm, and doubtless
its drift fruits are principally derived from Trinidad and the neigh-
bouring Venezuelan shores. In both islands we also find old dead
drift fruits incrusted with Balani that probably hail from the Amazon.

Of the Manicaria fruits brought by the currents to the beaches
of the Turks Islands not more than 1 or 2 per cent, appeared to be
" germinable." Out of some scores observed I only found one or
two in their cases, all the rest being bared fruits, and possessing in
almost all cases either a mouldy kernel with the embryo more or
less removed by decay, or a hard and dry kernel with the embryo
greatly shrivelled. The stranded fruits occurred on all the larger
islands; but they diminished in frequency towards the south, being
most numerous on Grand Turk in the north, and least common
on Greater Sand Cay in the extreme south, where, however, other
kinds of foreign drift abound. The indications are that these
Manicaria fruits often arrive at the Turk Islands from Hispaniola,
eighty or ninety miles to the southward.

On Grand Cayman, which lies in the track of the Main Equatorial
Current between Cuba and the coast of Honduras, quantities of these
Manicaria fruits are thrown up. Mr. Savage English in his paper
on this island in the Kew Bulletin (1913) remarks that occasionally
perfect fruits are found (such as have been already described in a
previous page from other localities); but no "sea coco-nut" has
ever been known to germinate on Grand Cayman, and " there is not
a tree of it on the island." He attributes the loss of the germinative
capacity to the long flotation in the sea involved in the transit from
Trinidad and South America. In a few cases signs of arrested
germination were observed when the fruits were opened. As indicative
of the source of these fruits, it is stated that a drifting bottle from
off Ceara, to the north-west of Cape St. Roque, was picked up on
the Cayman Islands.

On the whole it may be inferred that the floating fruits of Mani-
caria saccifera, as far as the retention of the germinative capacity
is concerned, possess, in spite of their great floating powers, but a
very limited capacity for distributing the species over wide tracts
of ocean, though able to traverse in an effective condition the narrow
seas dividing the West Indian islands, straits that rarely exceed
sixty miles across and have usually not half that breadth.

DiOCLEA REFLEXA, Hook. f.

This leguminous tree-chmber, which in many respects, as in its
distribution, station, habit, general seed-characters, and dispersal
by currents, presents much the same features as Mucuna urens,
ranges through the tropics of Asia, Africa, and America. From the
data given by various botanical authorities, more especially by
Urban, it is highly probable that all the larger West Indian islands,
and most of the smaller mountainous islands, possess it. Thus, it
is already known from Jamaica, Cuba, Porto Rico, Dominica, St.
Vincent, Tobago, Grenada, and Trinidad. But judging from my

FOREIGN DRIFT OF THE TURKS ISLANDS 131

own experience, and bearing in mind Grisebach's remark that it
is uncommon in Jamaica, it would appear that, widely distributed
as it is over this region, it is rarely frequent. Mucuna urens seems
to be three or four times as common, and this difference, as we shall
see, is reflected in the story of the stranded drift.

In the West Indies it climbs the lofty trees of the inland forests,
and especially favours the river-bank and the lake-side in wooded
districts, so that its seeds are likely to drop into inland waters and
to be carried down to the sea. But it also grows amongst the trees
lining estuaries, though it could not in this region be placed amongst
the typical coastal plants. The locality in which I especially studied
this species was on the forested slopes of the lake and effluent of
the Grand Etang in Grenada at elevations of 1800-2000 feet above
the sea. Doubtless it finds its station on the densely wooded banks
of the great rivers of Venezuela, the Guianas, and tropical Brazil;
but it is not easy to find direct references to its station in those
regions. However, Bentham, ascribes to it a station in woods
near rivers in the Amazon area, and mentions the Rio Negro in this
connection (Flora Brasiliensis of Martius, vol. 15, part 1). In tropical
West Africa it finds its home near the coast and at the riverside
(Hooker's Niger Flora.)

The seeds, though less frequent than those of Mucuna urens,
were found by the writer to be characteristic of beach-drift in Jamaica,
the Turks Islands, Grenada, Tobago, and Trinidad. They are
included in the Morris collection of Jamaican beach-drift in the Kew
Museum. Though those of Mucuna have often been recorded from
the drift stranded on European beaches, I have found no reference
to those of Dioclea reflecca. This is probably due in part to the cir-
cumstance that they have often been regarded as Mucuna seeds,
a confusion which is apparent in some of the older allusions to West
Indian drift on European beaches, and an instance is given below.
Except in size, the diameter being about an inch in both cases, the
appearance of such Dioclea and Mucuna drift seeds is dissimilar.
Whilst the two sorts of Mucuna seeds characteristic of European
beach-drift are orbicular in form, dark-grey in hue, and have a black
raphe nearly encircling them, the typical seed of Dioclea reflecca
shows black mottling on a light-brown ground, is squarish on one
side, and its raphe is limited to two-thirds of its circumference.

That the seeds of Dioclea reflexa are to be included amongst West
Indian drift stranded on European beaches, will be now established,
but they are far less common than those of Mucuna. Probably
at least ten Mucuna seeds are washed ashore for each Dioclea seed.
Although the writer has not found one himself on this side of the
Atlantic, a sound seed of D. reflexa stranded on the Shetland Islands
was sent to him by Mr. J. Tulloch of Lerwick for his inspection.
Then there is the curious circumstance that Dr. James Wallace, in
his enlarged edition (1700) of his father's book on the Orkney Islands
(1693), substitutes a figure of a seed of a Dioclea, most probably
D. reflecca, for one of Mucuna given in the earlier edition, as though
they represented the same seed. Since the seeds of this species
of Dioclea are able to reach the Shetland Islands, it would seem highly

132 PLANTS, SEEDS, AND CURRENTS

probable that they are cast ashore on the Norwegian coasts; but
the name is not included in the list of West Indian seeds and fruits
given by Sernander in his account of the Atlantic drift thrown up
on those shores. However, one may expect to find these drift
seeds also in the temperate latitudes of the South Atlantic. Hemsley
records Mr. Moseley's discovery of the seeds of Dioclea reflexa washed
ashore on Tristan da Cunha {Chall. Bot., IV., 291).

In my book on Seeds and Fruits (p. 103) allusion is made to the
habit of this climber of growing on trees beside streams in the moun-
tain forests of Grenada; and it is there shown how small would be
the percentage of seeds that would be fit for attempting the Atlantic
traverse. On this ground alone we are thus prepared to expect
that the seeds of this plant would not be so frequently observed
among the West Indian seeds thrown ashore on European coasts
as those of Mucuna. Judging from my results in the Turks Islands,
a locality which represents an early stage in the drifting of the seed
across the North Atlantic, the seeds of Dioclea reflexa are rather
less frequent than those of Mucuna urens and much less common
than those of the other species of Mucuna. In the drift of the Trini-
dad and Tobago beaches all three seem to be of equal frequency.
In the Turks Islands the seeds of Dioclea reflexa were generally
distributed in the drift, but were most frequent in the southernmost
island. It is interesting to note that of the seeds of this plant collected
in the beach-drift of this small group, 10 per cent, sank in fresh- water
though buoyant in sea-water. This may be compared with the
results of a similar experiment on the seeds of the same plant in the
beach-drift of Trinidad and Tobago. Here 30 per cent, sank in
fresh- water, though floating in sea- water.

No reference has been made to the occurrence of Dioclea reflexa
on the Pacific side of tropical America, as I possess no data directly
bearing on that point. However, its place is well supplied there
by Dioclea guianensis (Benth.), an allied species mentioned by
Seemann, under the synonym of D. panamensis, as growing by rivers
on both sides of the Panama Isthmus {Bot. Voy. H.M.S. Herald,
p. 109). This species is stated to be a native both of the Guianas
and of Ecuador ; and it is not unlikely that numerous Dioclea seeds,
which I found afloat in the drift of the Guayaquil estuary in Ecuador
and stranded on the beaches near its mouth, belong to this plant.

Doubtless there are several recorded facts illustrating the dis-
tribution of the seeds of Dioclea reflexa by currents in the tropics
of the Old World, but the following will be sufficient for the purpose.
Many years ago they were identified at Kew from collections of drift
seeds made by me on the beaches of Keeling Atoll in the Indian
Ocean and on the coral islets of the Solomon Group in the Pacific,
as well as from another collection of floating drift obtained by
Moseley off the coast of New Guinea {Journ. Vic. Inst., London, 1889 ;
Bot. Chall. Exped., IV., 291, 309, 311).

But there is an allied species of Dioclea, D. violacea, Mart., which
plays a similar role in the tropical Pacific. I was familiar with its
seeds in Hawaii and Fiji, and frequent mention is made of them in
my work on Plant Dispersal. They are commonly brought down by

FOREIGN DRIFT OF THE TURKS ISLANDS 133

the rivers and deposited on beaches in Fiji, and my experiments
showed that they can float for a year and more unharmed in sea-
water. There is, however, a difficulty connected with the distribution
of this species. It seems from Hemsley's reference to it (Bot. Chall.
Exped., IV., 291) to have been first described from Brazil. Yet if
it is so widely distributed by currents in the Pacific, having been
recorded from Hawaii, Fiji, Tahiti, etc., it is strange that it should
only be confined to Brazil in the New World and that its seeds do
not figure in West Indian beach-drift.

Interesting as the genus Dioclea is to the student of distribution,
it only repeats the problems displayed by two other genera of legumi-
nous tree-climbers, Mucuna and Entada, all three of them holding
species possessing seeds capable of wide dispersal by currents, species
that range over the tropics of the globe, and all three of them con-
taining species of more limited range that, certainly in Entada and
probably also in the other two genera, are not adapted for this
mode of dispersal. These three genera thus behave like other
leguminous tropical genera, such as Canavalia, Guilandina, Sophora,
etc., that hold littoral species, found round the tropical zone, plants
possessing buoyant seeds known to be distributed by currents far
and wide over the oceans; whilst they own other species restricted
to smaller areas and not capable of dispersal by the currents. In
neither case could the agency of the current be appealed to in explana-
tion of the distribution of the genera round the tropics. It is only
the species of the estuary and of the beach that offer in the buoyancy
of their seeds the opportunity for the currents. Species that habitu-
ally grow away from the sea-beach on the river-bank as a rule possess
seeds that sink, a fact brought out in my book on Plant Dispersal.
These inland species with their limited range largely make up the
genus, the distribution of which around the world opens up very
different issues.

Sacoglottis amazonica, Mart. (Humiriacece)

This is one of the most interesting of the West Indian drift fruits
that have been found on European beaches. Though characteristic
of West Indian beach-drift, this fruit can scarcely be said to
belong to a West Indian plant, since the small tree to which it belongs
has its home in the Amazon estuary, and is otherwise only known
from the island of Trinidad, where it is of very rare occurrence. It
is, however, highly probable that the tree will be found in the estuary
of the Orinoco, if it has not already there been found. There is
no other fruit or seed amongst the West Indian drift of European
beaches, about which it may be assumed with such confidence that
the original source was one of the great estuaries of the South
American mainland between the Equator and the Gulf of Paria,
most probably the Lower Amazon.

The story of the mystery that long surrounded the parentage of
these drift fruits was told in Nature many years ago (January 31,
1889; November 21, 1895) by Mr. Morris (now Sir Daniel Morris).
Although they had been known for two centuries and more, not only

134 PLANTS, SEEDS, AND CURRENTS

amongst the strange constituents of Jamaican beach-drift but in
European collections of curious seeds and fruits found on our beaches,
it was not until 1889 that the parent plant was discovered. The
subject was re-opened when Morris recognised in a drift fruit picked
up at Bigbury Bay, South Devon, by Mrs. Hubbard in 1887, the same
fruit that he had gathered on Jamaican beaches in 1884. Several
botanists aided in the inquiry, Hillier, Oliver, Stapf, Urban and others ;
but the source was definitely established when Mr. Hart in 1889
sent from Trinidad to Kew some drawings made by Dr. Crueger
in 1861, both botanists that in turn filled the position of Superin-
tendent of the Botanic Gardens of Trinidad.

Much of what follows was written before the author became
acquainted with the fact that Morris had made a comprehensive
investigation of the subject. The present writer had also dug
deeply into the older botanical literature ; but here also he has been
largely forestalled. Almost all that is of importance to the student
of distribution respecting Sacoglottis amazonica was told long ago
by Morris. However, as my investigations have been quite indepen-
dent, and also because my account helps to fill up some of the gaps
in the earlier researches, more especially in the handling of the drift
fruits over a large area of the West Indian region, I venture to give
my results much as they were written out before the papers of Morris
in Nature were consulted.

It is singular that Mr. Hart first introduced me to the parent
plants of these strange drift fruits, with which I had been previously
familiar on the beaches of Jamaica and Colon. Within an hour
of my landing at Port of Spain in Trinidad, in December 1908, I
was in the Botanic Gardens talking to a stranger about my diffi-
culties in finding the parent plants of some of the seeds and fruits
in West Indian beach-drift. He took me into the Herbarium and
showed me some specimens. The stranger was Mr. Hart and the
specimens were those of Sacoglottis amazonica. From him I learned
that the small tree, to which the fruits belonged, grew in the estuaries
of the Orinoco and the Amazon, and that if I wished to see it in its
home I ought to visit those regions, since it was very rarely to be
found on the swampy coasts of Trinidad.

These drift fruits are spread far and wide over the West Indian
region. I found them on the beaches at Colon, in Jamaica, and on
the Turks Islands, Tobago, and Trinidad. There are specimens in
the Kew Museum from Barbados, and Morris refers to one found
afloat off an island between Grenada and St. Vincent. As before
noted they were found by Morris in 1884 on the south coast of Jamaica,
and almost two centuries before, 1688-9, they were observed by
Sloane during his residence on this island to be frequently cast up
on its shores.

Although, as far as I know, not recorded from any island in the
West Indian region except Trinidad, the regular occurrence of its
drift fruits on the beaches of the Turks Islands, at the south-eastern
end of the Bahamas, renders it highly probable that the plant grows
on the large islands to the southward and eastward, such as Porto
Rico and San Domingo, since it is from that direction that much of

FOREIGN DRIFT OF THE TURKS ISLANDS 135

the foreiflfn drift reaches this small group. It is a tree of the Amazon
delta and of the Middle Amazon, growing in woods on the river-
bank. It is accordingly something more than an estuarine tree,
since it extends far up the great river and has been found at Teffe
some distance above the confluences of the Negro and the Madeira
with the main stream. The latest reference I have found to the
distribution of this tree is that given by Stapf in Morris's paper of
1895. We learn from the Index Kewensis that the genus holds
about ten known species, of which nine are Brazilian and one is
found in the Guianas. Probably Sacoglottis amazonica is the only
species that is dispersed by the currents; and it is pointed out in
Chapter IV. that the limitation of this tree to the New World appears
to be entirely a question of the arrangement of the currents, which
would readily transport the fruits in a sound and effective condition
from tropical West Africa to Brazil, but not from the tropics of the
New World to West Africa.

Before dealing with these fruits from the standpoint of their
fitness for dispersal by currents, I will observe that they were charac-
terised by Morris as possessing " ideal qualities " as drift fruits,
their great buoyancy being due, as he points out, to numerous closed
cavities or resin-cysts. The typical drift fruit, as he explains, has
lost the outer fleshy covering of the fresh fruit. He found that two
of the normal five cells of the fruit were usually suppressed. His
account is illustrated by excellent figures of the fruit.

They presented themselves to me in West Indian beach-drift
as oblong woody fruits, about two inches long, and usually two-
seeded. After the detachment of the ripe fruit from the tree, the
outer fleshy covering evidently dries up and forms a dark-brown
skin, which is soon lost in the " wear-and-tear " of the drift, and is
only to be observed with fruits that have not travelled very far from
the parent plant. When stripped of the outer skin the drift fruit
presents a remarkable appearance on account of the rounded
" bulgings " on the surface, which correspond to the empty resin-
cavities beneath. It is in this bared condition as light-coloured
warty ligneous fruits that they generally occur in West Indian
beach-drift, the outer dark skin, two or three millimetres in thickness,
having been lost, as above stated, in the " wear-and-tear " of sea
transport. The two seeds lie in the centre of the fruit. They
occupy long cells two-thirds of the fruit's length, but appear to be
perfectly protected against the penetration of sea-water. Any
weak place in the equipment of the seeds for traversing an ocean
unharmed would be expected rather in the inherent inability of
the seed to retain its germinative capacity for a period sufficiently
long than in any defect in the protection afforded by the fruit-case.

It is only at the extreme south-east corner of the West Indian
region, namely, in the islands of Trinidad and Tobago, that these
drift fruits present themselves on the beaches in a more or less
entire state, that is to say, with the outer skin in a more or less
perfect condition. The bared state, as Morris points out, is the typical
condition of the drift fruit. In Jamaica they are always bared,
and the same may be said of those in the beach- drift of the Turks

136 PLANTS, SEEDS, AND CURRENTS

Islands. On the beaches of the south coast of Trinidad these fruits
are amongst the commonest constituents of the drift, and the seeds
are often fresh. On the south-eastern beaches of Tobago, where
the fruits are common, about a third of them contained sound
healthy seeds. Since the tree is very rare on Trinidad and does
not grow on Tobago, it is obvious that the fruits so characteristic
of their beaches belong to the drift of the Orinoco and the Amazon ;
and it is not surprising that in islands nearest to the true home of
the tree the drift fruits should sometimes retain their outer coverings,
and that the seeds should be often fresh. In the drift of the Turks
Islands only about a fifth possess healthy seeds; but in this small
group the seeds do not seem to be able to retain their sound appearance
for a long time in the drift. However, though usually in scanty
numbers, these drift fruits are to be observed on every beach of
the Turks Islands, where the foreign drift collects in any quantity,
from Grand Turk to Greater Sand Cay, at the extreme ends of the
group.

These fruits float buoyantly for many months. Three fruits
from the Tobago beach-drift were placed in sea-water two years
after their collection, and all still floated buoyantly seven and a half
months later. In two of them the seeds proved to be discoloured
and seemingly dead. In the third they appeared to be fairly sound.
From the results of this experiment as well as from the indications
supplied by the condition of the seeds in the stranded fruits on West
Indian beaches as above described, it would seem that although
the fruits would be able to withstand the immersion of a year and
a half, which would be involved in their transport to the coasts of
Europe, the seeds would probably lose their germinative capacity
after the first six months. The floating power is to be entirely
ascribed to the numerous impervious round empty cavities (3 to 5
mm. across) in the substance of the woody case and to the impermeable
outer surface of the fruit, when deprived of its skin. Neither the
substance of the fruit nor the seeds possess independent buoyancy.

It is apparent that Morris formed a similar estimate of the unfitness
of the seeds for reproducing the plant after a prolonged ocean
traverse. Though impressed with the ideal qualities of the fruit,
as far as buoyancy is concerned, he remarked that there is " no
record that the seeds have germinated after long immersion in salt
water, or that the plant has established itself in a new locality outside
its present area." As regards the last point it may be observed that
it would scarcely be possible to discover such a record in the case
of any large West Indian island, not even for Jamaica. We could
not expect any proof more valuable than that which is supplied by
the very scanty representation of Sacoglottis amazonica on the south-
east coast of Trinidad.

From what has just been said we would expect to find the fruits
of Sacoglottis amazonica on European beaches, though not with
sound seeds; and reference has already been made to a specimen
in the Kew Museum which was picked up in 1887 by Mrs. Hubbard
on the Devonshire coast. But from data given by Sloane in his
Natural History of Jamaica (II., 186) it is apparent that these fruits

FOREIGN DRIFT OF THE TURKS ISLANDS 137

have long been known as constituents of the West Indian drift
brought by the Gulf Stream to the shores of Europe. Although
the parent plant was not known to him, he was able to compare
its fruit with the accounts given by Petiver and others. " This is
frequently cast up " (thus Sloane writes) " on the shores of this island
(Jamaica) by the waves, and is one of those fruits thrown on the north-
west islands of Scotland by the seas." He quotes the description
given in a work thus designated — J. B. Cat. Jam., p. 214, " Fructus
exoticus cinereus, cum lineis et tuberculis duris." He also gives
Petiver' s description of his drawing of the fruit in his Gazophylacium
Naturce (tab. 71, p. 5), " Fructus Jam. ovalis foraminosus," and the
same author's account of " a hard oval fruit, with seed-holes round
its surface, found on the shores of Jamaica," etc. Petiver' s figure
and description, which I found in the 1764 edition of his book (plate
71, p. 7), leave no doubt as to the identity of the fruit mentioned
by Sloane as commonly stranded on the north-west islands of Scot-
land. Probably these fruits were often figured in the works of
the early botanists. Thus one is figured and well described by
Clusius {Exot. Libr., libr. II., cap. 19, p. 45 ; 1605) as sent to him by
Jacobus Plateau, but nothing more is said of its source.

In the remarks just made I have briefly given the results of my
examination of the older literature relating to the strange drift
fruits of Sacoglottis amazonica, both on West Indian and European
beaches. Since they were written, I have enjoyed the privilege
of reading the papers of Sir D. Morris, who, with the assistance of
Mr. E. G. Baker, made a more extensive inquiry in this direction,
though I am not clear whether either of them noticed Sloane' s re-
cognition of these fruits as thrown up on the north-west islands of
Scotland. My references to the older literature may now be supple-
mented from these sources. The description and figure given by
Clusius in his work of 1605 were reproduced by J. Bauhin in 1680
ill his Historia Plantarum (tom. i., libr. 3, cap. cxi., fig. 1). One of
the earlier allusions to this drift fruit is that of Johannes Jonston,
who described it in his Historia Naturalis de Arhorihus et Fructibus
(p. 102), a work published in 1662. It was mentioned by Sloane
as early as 1696 in his Catalogus Plantarum (p. 214); and here one
may find an explanation of a reference of his in the preceding para-
graph, J. B. apparently indicating J. Bauhin. Its discovery by Mr.
E. G. Baker in the Sloane Collection in the British Museum, under
label No. 1656, was of much assistance to Sir D. Morris in clearing
up the mystery surrounding the origin of these drift fruits.

CHAPTER VII

THE LARGER FOREIGN DRIFT OF THE TURKS ISLANDS (continued)
GUILANDINA BONDUCELLA, L.

Since this plant and its seeds are discussed at length in my books
on Plant Dispersal and on Seeds and Fruits, it is only necessary to
repeat here that the seeds are able to float for years unharmed in
the sea and that they retain their germinative capacity after being
stranded on the shores of Europe. For the last two centuries and
more it has been known that the seeds of this plant are frequently
cast up on European beaches. This subject is dealt with in Chapter
II. ; but it may be here observed that the writer himself found a
seed, apparently sound, in April 1909, on a beach near Salcombe in
South Devon. For many years and in several parts of the tropical
zone, he has been familiar with this littoral shrub. Here, however,
his remarks will be chiefly restricted to the results of his observations
in the West Indian region.

As a coast plant it is generally distributed in the West Indies from
Jamaica to Trinidad. It occurs as frequently on small as on large
islands ; and noteworthy amongst the former are the Cayman Islands
where it was found by Millspaugh (Plantce Utowance). In Jamaica
it came under my notice on the borders of nearly every beach ex-
amined on the north and south coasts. It also came under my
observation on St. Croix, Grenada, the Turks Islands, etc., as well
as on the Colombian coast near Cartagena. Its seeds form a regular
constituent of West Indian beach-drift, and came especially under
my notice in this connection in Jamaica and the Turks Islands.

This plant was observed by me only on Grand Turk, the northern-
most of the Turks Islands; yet its seeds occur in the drift of the
other islands of this small group under circumstances indicating that
they formed a part of the general drift brought to these islands from
the southward and eastward. Though not very frequent, a circum-
stance probably due to their often being covered over by the heaped-
up larger drift materials, a few of the seeds came under my notice
on all the Turks Islands where drift had accumulated in any
quantity on the beaches. On Grand Turk it thrives in places away
from the beach in dry, rocky situations, especially in the northern
part; and it only came down to the coast in places where the usual
inland vegetation reached the beach. Since the seeds are regularly
brought to this small group from outside regions by the currents,
the limited occurrence of the plant is remarkable. There is evidently

138

FOREIGN DRIFT OF THE TURKS ISLANDS 139

some influence that inhibits the estabhshment of Guilandina bonducella
as a Uttoral plant in these islands. As I found a few seedUngs on
the beaches of Grand Turk, it is apparent that the excluding cause
comes into operation after this stage. It may be that goats and
other animals browse on the young plants, since the soft prickles
that grow on the stems and on the under surface of the foliage could
offer no protection, though when they harden in the older plants
such protection would be afforded.

It is probable that the same cause which prevents this plant from
assuming its characteristic littoral station on the Turks Islands has
operated throughout the Bahamas, an archipelago to which this
small group geographically belongs. I did not find it included in
the manuscript of Britton's and Millspaugh's Flora of the Bahamas,
its place in those islands being taken by the allied species, Guilandina
bonduc, which grows in coastal thickets. Neither species was recorded
by Lansing in his thorough examination of the Florida keys (west
of Key West). It is also apparent that although the seeds must
often be stranded on the Bermudian islands, where several West
Indian shore plants have found a home, the plant has not succeeded
in establishing itself there, since General Lefroy's remark that it
has only once been found {Chall. Bot., IL, 30, 129) would scarcely
justify us in considering it a successful colonist. On account of its
cosmopolitan distribution as a littoral plant in warm latitudes we
are apt to infer that it could make its home everywhere; but the
foregoing negative facts of its distribution will prevent us from
forming such a conclusion.

In my book on Plant Dispersal (p. 192) it is stated that almost
without exception the seeds of littoral plants of Ccesalpinia bonducella
(Guilandina bonducella) in Fiji floated both in sea- water and in fresh-
water, whilst in Hawaii the seeds of the same species growing inland
all sank. (On consulting my Fijian note-books I find that out of
forty-seven seeds from three different coast localities all floated in
fresh- water.) I made some additional observations on these two
points in the W^est Indies, that is to say, on the relative buoyancy of
the seeds in fresh and salt water, and on the influence of an inland
station on the floating capacity. With regard to the first point it
may here be said that out of sixty-eight seeds obtained from plants
growing by the beach at Savanna-la-mar in Jamaica 75 per cent,
floated in fresh- water and 84 per cent, in sea- water. Of eighty seeds
from plants growing by the beach near St. George's in Grenada
95 per cent, floated in fresh-water and 98 in sea-water. Out of
fourteen seeds collected from the beach-drift near Seville in Jamaica
all floated in sea- water, but only twelve or 86 per cent, in fresh-water.
It is thus evident that in the West Indies not quite all of the seeds
of littoral plants float in sea- water, and that of those that are buoyant
in sea- water not quite all float in fresh- water. We should represent
a rough average result if we said that of a hundred seeds of plants
growing by the beach ninety float in sea- water and eighty in fresh-
water.

Concerning the effect of an inland station on the buoyancy of the
seeds I found that of a hundred seeds gathered from plants growing

140 PLANTS, SEEDS, AND CURRENTS

half a mile from the beach in Grand Turk all floated in sea- water and
fresh-water. It appears, then, that an inland station does not
deprive the seeds of their buoyancy in the Turks Islands, though
in the case of plants growing inland on the old lava-fields of Hawaii
this effect was produced.

There seems at one time to have been a trade in the seeds of
G. bonducella and G. bonduc between the New and the Old World.
Sloane makes the curious observation (Nat. Hist. Jam., II., 41) that
those of the grey-seeded " Nicker " plant (G. bonducella) were much
esteemed for their medicinal virtues by the Turks. Respecting those
of the yellow-seeded " Nicker " plant {G. bonduc) of the West Indies
he writes that " the seeds are brought very plentifully into Europe
for making buttons " {Ibid.).

I am indebted to Prof. Ewart for the record of the occurrence of
two stranded seeds of Guilandina bonducella on the shores of South
Austraha. They were found by Miss M. O'Dowd in 1912. He
considers that they may have been transported there from the
Queensland coast. They, however, did not prove to be germinable.
As far as the current connections are concerned, it seems to me
more likely that if brought from a distance these seeds must have
hailed originally from Tropical East Africa or Madagascar. In that
case they would have been carried by the Agulhas Stream within
the influence of the West Wind Drift Current, and then across the
Indian Ocean to Australia. This source is distinctly indicated by
the tracks of bottle-drift reaching the Great Australian Bight, a
subject discussed in Chapter XIII.

Hymen^a

Amongst the characteristic fruits of the Turks Islands drift occur
two kinds of ligneous indehiscent legumes, of which one kind was
identified by Prof. Pax as the fruit of Hymencea courbaril, the West
Indian Locust-tree, whilst the other he considered to belong to an
allied species of the same genus. These drift pods often occur entire
with sound seeds ; whilst at other times some or all of the seeds are
decayed.

Hymencea courbaril is a tall tree found over much of the West
Indies and on the Central and South American mainland from
Panama to the Guianas. As concerning its insular distribution, the
fact that it occurs in Cuba, Jamaica, Porto Rico, Antigua, Dominica,
St. Lucia, Trinidad, etc., indicates its wide range. It grows both in
inland plains and in river valleys. In Jamaica it flourishes in all
parts of the island and especially up the valley of the Black River
(Fruits, etc., of Jamaica, by E. J. Wortley, Kingston, 1906). The
legumes of this tree, as they occur in the drift of the Turks Islands,
are broad, flat, 5 or 6 inches long, and contain about six seeds
in a dry fibrous pulp that fills the fruit cavity. The seeds possess
no buoyancy, and could only be transported across tracts of sea by
the floating pod, which seems stout enough (the thickness of the
walls being 3 to 4 mm.) to withstand the wear-and-tear of a passage
across the Atlantic, though it is doubtful whether it would retain

FOREIGN DRIFT OF THE TURKS ISLANDS 141

its buoyancy for the many months that would be occupied in the
traverse.

The other pods, which are about 4 inches long and roundish rather
than flat in section, hold about four seeds, enclosed in a similar dry
pulp, of which some float and others sink in sea- water. The remarks
above made concerning the fitness for being transported across the
ocean apply also to these fruits. As far as I know no Hymencea
pods have been recorded amongst West Indian drift on European
coasts.

Carapa guianensis, Aubl.

Carapa as a littoral genus is linked with Rhizophora not only in
its present distribution but probably also in its past associations.
Carapa, like Rhizophora, with which it is often associated in coastal
swamp regions, has only a few species, the first-named possessing
only five or six and the last three or four. In both cases the genus
is mainly of the Old World, lending a species to the American conti-
nent which holds it in common with the African West Coast. In
both genera, therefore, the presumption is that the origin is Asiatic.

Many critical questions of great importance are raised when we
come to discuss the distribution of these two genera, questions, I
may add, that were ably put by Schimper years ago in his study of
the Indo-Malayan coast flora. Both, as already indicated, are littoral
genera, frequenting in the case of Rhizophora coastal and estuarine
swamps exclusively, and in that of Carapa both the swamp and the
dry beach. In both cases there are two species that divide the
warm regions of the globe between them in the same peculiar fashion,
one appropriating America and the West Coast of Africa, the other
monopolising the rest of the tropical zone from the East Coast of
Africa eastward to the Western Pacific. In the instance of Rhizo-
phora there are not wanting localities where the Old World species
(Rh. mucronata) and the New World species (Rh. mangle) meet, as
in Fiji, a matter discussed at length in my work on Plant Dispersal.
As far as I can ascertain the two species of Carapa that hold the
Tropics between them never meet on common ground, C. guianensis
making its home in the warm regions of the New World and on the
tropical coasts of West Africa, and C. moluccensis ranging from
the Zambesi eastward to distant Fiji. [There is no need to raise
the question here whether C. moluccensis. Lam., is distinct from
C. ohovata, BL, another Asiatic form, since the distribution is much
the same, and the student of dispersal cannot distinguish between
the seeds of the two forms (see Chall. Bot., IV., 290).]

Carapa guianensis is one of the features in the estuarine vegetation
of the large rivers of Brazil, the Guianas, and Venezuela, and occupies
a similar station in the adjacent West Indian island of Trinidad.
Its occurrence in the Orinoco estuary accounts for the presence of
so many of its seeds amongst the Orinoco drift on the south coast
of Trinidad. The tree is abundant in the Lower Amazon, as at
Para, and Spruce speaks of it as " met with all the way up the
Amazon " {Botanist on the Amazon, etc., edited by Wallace, 1908,
I., 480). I have not found, however, any reference to its occurrence

142 PLANTS, SEEDS, AND CURRENTS

on the Pacific side of tropical America, and in that respect the com-
parison with Rhizophora mangle is incomplete.

With the two species of Carapa that between them cover the tropics
of the globe the writer is familiar, having studied the trees together
with their fruits and seeds in Fiji and in Trinidad, and having gathered
their seeds from the floating river-drift and the stranded beach-drift
of various parts of the world, as on the south coast of Java, in the
Keeling Islands, in Fiji, and in the West Indies. Though it does
not seem that Treub found stranded Carapa seeds on the beaches
of the devastated island of Krakatau, when he visited it in 1886,
nearly three years after the great eruption, those of C. moluccensis
were observed by Penzig in 1897 ; and when Ernst and other botanists
examined this locality in 1906 they found Carapa trees established.
The species was referred by them to C. ohovata ; but there can be
little doubt that the trees grew from such stranded seeds as were
previously observed by Penzig, the two forms not being distinguish-
able by their seeds {vide Treub and Penzig in Annates du jardin
hotanique de Buitenzorg, 1888 and 1902, and Ernst's New Flora of
Krakatau, 1908).

Carapa seeds were frequently noticed by me in the floating drift
of the Rewa estuary in Fiji, and often in a germinating condition.
They must form a feature in the drift of the estuary of the Orinoco,
since many more drift seeds are piled up on the southern coasts of
Trinidad than could have been derived from the trees in the coast
districts of that island. We cannot doubt that they are equally
abundant in the floating drift of the Amazon and of the rivers of
the Guianas.

But the grave perils that threaten the floating and the stranded
Carapa seeds lessen their effective value for oceanic dispersal. In
the first place, there is the tendency to germinate when afloat in an
estuary before the sea passage begins. Then there is the tendency
to germinate prematurely after being stranded on the beach at the
completion of a long sea traverse. This, I especially noticed, in the
Keeling Islands, where after a drifting passage of at least 700 miles
the seeds often sprouted on the beach, the protruding portions either
falling a prey to the crabs or being withered up in the sun. Then
there is the danger from the attack of boring molluscs and other
marine creatures during the ocean passage. This presented itself as
a very real risk in the case of seeds of Carapa moluccensis that I
found stranded in the Keeling Islands and on the south coast of
West Java. Here the empty cavity was often occupied by the tubes
of the Teredo. As a result of these repressive influences Carapa
moluccensis seems never to have been able to establish itself on the
Keeling Islands. Yet it may be remarked that the tendency to rapid
germination on the part of a stranded seed, whilst usually leading
to fatal results on an exposed sandy beach, would be a direct advan-
tage on the muddy shores of a mangrove-fringed coast, where the
germinating seed could at once strike into the mud in the shade of
the trees.

With respect to the occurrence of the seeds of Carapa guianensis
in the beach-drift of the West Indian region, the following remarks

FOREIGN DRIFT OF THE TURKS ISLANDS 143

may be made. They were included in the drift collection made by
Morris on the south coast of Jamaica (Chall. Bot., IV., 299), but
nothing is said as to their condition. As the plant is not known
from this island, the seeds were probably brought by the Equatorial
Current in its passage across the Caribbean Sea. The seeds often
came under my notice on the beaches of Trinidad, where the tree
is at home. On the south coast very few of them were in a sound,
fresh condition, many of them showing evidence of prolonged flota-
tion in the sea in the incrusting shells of cirripedes and of other
marine organisms, whilst others had been probably brought down
by the Orinoco, since they were in a germinating but dried-up con-
dition. On the north coast, as at Grande Riviere, they were more or
less fresh, and had evidently been recently brought down by the
river. They were frequent on the east coast of Tobago, often
incrusted by cirripedes ; but as far as I know the plant is not found
in the island. In the Turks Islands they mostly came under my
notice on the east side of Grand Turk, half of them being empty,
whilst not more than one in ten possessed sound seeds.

Of the four West Indian localities above mentioned which dis-
played the fruits of Carapa guianensis in the beach-drift — namely,
Jamaica, Trinidad, Tobago, and Turks Islands, only the second as
far as I know owns the parent plant. But from the regular occur-
rence of the seeds in the drift of the Turks Islands, where the tree
certainly does not grow, it may be inferred that the species is at
home in the islands to the southward and eastward (San Domingo,
Porto Rico, etc.), from which the drift seems to be largely derived.
According to the writings of Grisebach, Hemsley, Spruce, and
Schimper, the tree grows on the mainland at the coasts and in the
estuaries of Central America, Venezuela, the Guianas, and Brazil.

The fact that Carapa guianensis also grows on the coast of Sene-
gambia in West Africa raises the issue as to the seed's capacity of
crossing the Atlantic in a germinable state. Although the seeds
will evidently float for many months in the sea, from the indications
above given it is doubtful whether they would retain their germina-
tive powers for so long a period. The risks, as I have shown, are
great and numerous. It is especially questionable whether the seeds
would withstand a sea passage of more than two or three months,
or, in other words, whether for the purpose of effective dispersal
they are fit for much more than distribution by the currents over
the islands of the Caribbean Sea. This would quite exclude the
possibility of their being able to reach in a sound state the tropical
coasts of West Africa from the New World by the Gulf Stream
route, which even by the way of the Azores would occupy twelve
months and more. But, as we have seen, Carapa is mainly an Old
World genus, the New World being presumably the recipient rather
than the distributor. In that event it is quite possible that the
seeds could accomplish the much shorter ocean passage, occupying
only three or four months, in the stream of the Main Equatorial
Current from the Gulf of Guinea to the coast of Brazil, a subject
discussed in Chapter III. The fact that seeds of Carapa moluccensis
are often cast up in the fresh condition on the shores of Keeling

144 PLANTS, SEEDS, AND CURRENTS

Atoll, after a drifting voyage of at least 700 miles and a passage that
would require at least seven or eight weeks, renders this route across
the Atlantic possible for the seeds of Carapa guianensis.

MaMMEA AMERICANA, L.

This well-known West Indian tree belongs to a small genus which
has a remarkable discontinuous distribution. It holds six known
species, of which three are tropical American and three are peculiar
to Madagascar (Index Kewensis). In belonging to a genus of this
description Mammea americana resembles several other trees that
are referred to in this work in connection with drift. These dis-
continuous tropical genera have a great importance.

According to Grisebach and Urban this tree, which is confined to
the New World, ranges from Cuba and Jamaica to Brazil, and is
widely distributed in the greater and smaller West Indian Islands.
It grows in the lower mountain forests of Jamaica, the locality where
I made its acquaintance, and it is as a West Indian forest tree that
it finds its natural station (see also Harshberger's work, p. 688,
concerning its station in the islands of St. Thomas and St. John).

The large russet-coloured drupes, four to six inches across, con-
tain usually two or three large " stones," each consisting of a fibro-
ligneous endocarp encasing the seed. Inside the tough skin of the
fruit is a firm fleshy pulp. The fresh " stones " have no buoyancy;
but since the pericarp is buoyant, it is probable that the fruit would
float at first, though not for long, as the soft coverings would soon
decay. The " stones " evidently acquire their floating power when
drying on the ground after being freed from the fruit, the buoyancy
being due partly to the dried endocarp and partly to the unfilled
space arising from the shrinking of the seed. Though edible in a
general sense for man, the fruits are more appreciated by animals.
In Jamaica, according to Sloane, wild swine feed upon them. When
dried after removal from the fruit the " stones " have a rough, pitted
exterior; but as they occur in the beach-drift, after undergoing the
wear-and-tear of sea transport, their surface is usually smooth and
marked by interlacing fibres which give them a peculiar appearance.
In this condition the " stones " are generally two and a half to three
inches long and ovoid in shape.

I found the " stones " in the beach-drift on the north coast of
Jamaica (as at St. Anne's), on the south-east coast of Tobago, on
the south coast of Trinidad, and on the Turks Islands. In the
group of islands last named they form a regular constituent of the
beach-drift, and came under my notice wherever the drift had
collected in any quantity, as on Grand Turk, Cotton Cay, Salt Cay,
and Greater Sand Cay ; but I rarely observed more than two or three
on each beach. In all the four West Indian localities above men-
tioned, the " stones " of the beach-drift gave little promise of being
effective agents in the dispersal of the species by currents. Usually
in half the cases the seed had decayed away; whilst in the rest,
though the seed appeared sound, its hard consistence and dead-
looking aspect on section did not indicate the retention of the germin-

FOREIGN DRIFT OF THE TURKS ISLANDS 145

ative capacity. It is thus evident that the tree possesses but little
fitness for effective trans-oceanic dispersal by currents; and it may
be inferred that if the fruits, in the shape of the " stones," ever
reached the shores of Europe, which is unlikely, they would either
be empty or would contain decaying seeds.

But we may go further and observe that it is more than doubtful
whether the agency of the currents could be appealed to for an
explanation of the distribution of this tree over a large part of the
tropics of the New World. The reason of its representation in the
drift is probably to be found in its station on the forested slopes
of river valleys, from which the bared " stones " of the fruits could
be swept down into the rivers during torrential rains. If at times
they are carried by the sea currents in a sound state from one island
to another, the coast would offer a most unsuitable station for the
establishment of a typical tree of the inland forests. It is possible
that man has aided in its dispersal, since the edible fruit is appre-
ciated by natives; but the main factor is, I think, to be looked for
in the past, when the area of its distribution had not been broken
up in the great changes which have resulted in the detachment of
the large West Indian islands from the South American mainland,
a matter referred to on other pages of this work.

In his account of the Cayman Islands, Mr. Savage English (Kezv
Bulletin, 1913) tells us that the fruits of this tree are occasionally
thrown up on Grand Cayman " in a more or less eatable condition " ;
and he thinks that the tree may ultimately be introduced by the
currents. However, it is already included in the flora of the Cayman
Islands (Urban, Symholce Antillance, IV., 412); and if brought from
a distance the drift fruits in question doubtless came from the
neighbouring shores of Cuba and Jamaica.

Gourds and Calabashes of the genus Crescentia

In my work on Plant Dispersal (p. 570) it is observed that gourds
and calabashes of Cucurbitaceous plants are frequently brought
down to the sea in tropical regions and are thus likely to be dis-
persed by the currents. Floating in the estuaries and stranded
on the beaches, the gourds of a Cucurhita came often under my
notice in Fiji; and their suitability for dispersing the species was
established in one case, where seeds from a fruit that had been
floating for at least two months in sea-water germinated in a few
days.

Gourds, usually small in size, w^ere frequently observed by the
writer afloat in the drift of the estuary of the Guayas in Ecuador,
as well as stranded on the neighbouring beaches. Some of them
were cucurbitaceous; but others were the wild fruits of Crescentia
cujete, the Calabash tree, which belongs to quite a different family,
the Bignoniacece. It was not until some years afterwards that he
recognised these Crescentia fruits amongst his Ecuadorian drift-
collections, having in the interval become acquainted with the tree
in the W^est Indies. However, although the writer was not aware
of it, they had long before been identified as gourds of Crescentia

L

146 PLANTS, SEEDS, AND CURRENTS

cujete in a collection of Ecuadorian drift fruits and seeds which he
had sent on his return to England to the Kew Museum.

Gourds of sorts have long been known to be thrown up on the
coasts of Europe. They are usually referred to as belonging to
Lagenaria vulgaris (Cucurbita lagenaria), the calabash gourd of the
Old World, and were long ago familiar to Scandinavian naturalists
amongst the foreign drift cast up on their shores. Sernander deals
with this subject on p. 119 of his work on the Distribution-Biology
of the Scandinavian Plant-World (Upsala, 1901), and Hemsley refers
to it in his Report on the Botany of the Challenger Expedition
(IV., 277). These gourds of the Norwegian beach-drift were first
described by Tonning, a pupil of Linnaeus. Found by Strom and
Gunnerus in the eighteenth century and by Lindman in recent
times, they have been in all cases referred to Lagenaria vulgaris.
According to Sernander, the gourds stranded on Scandinavian
beaches are usually " worked " calabashes ; but he alludes to one
that was not carved in this fashion, which contained several seeds.

It is highly probable, however, that some of the gourds and cala-
bashes recorded from the Scandinavian beach-drift were fruits of
Crescentia cujete w^hich had been brought in the Gulf Stream drift
from the West Indies. By all the authors they are placed amongst
the Gulf Stream materials heaped up on those coasts and associated
with tropical seeds, such as those of Entada scandens and Mucuna
urens, which are recognised as commonly brought by the currents
to the Scandinavian shores from the West Indies. It will be shown
below that gourds and calabashes of the genus Crescentia are very
typical of West Indian beach-drift. The reason why their real
character has been overlooked in the case of those found in European
beach-drift may be found in the circumstance that unless one is
familiar with the fruits in their homes, it is necessary to break open
the gourd to identify the genus, and the discoverer of such a stranded
fruit on a beach in Europe would probably be loth to spoil his
specimen.

Crescentia includes five species all confined to the tropical regions
of the New World. The most familiar species is C. cujete, the Cala-
bash tree, which is distributed over the West Indies, and on the
American mainland from Mexico to Brazil. One would be inclined
to think that man in the past must have assisted in its distribution,
since its gourds are extensively employed as water vessels; but it is
noteworthy that another species, C. cucurbitina, L., which is referred
to below, has a range almost as wide, notwithstanding that its fruits
seem to be of little use to man. The Calabash tree thrives in Bermuda
with all the appearance of being indigenous ; but Rein had grounds
for suspecting that it had been introduced, and accordingly Hemsley
does not include it in the indigenous Bermudian flora (Chall. Bot.,
II., 9, 55). The gourds of this tree are those most usually found in
West Indian beach-drift. However, another species of Crescentia,
C. cucurbitina, as above named, is not infrequently represented in
the drift of this region. The tree, according to Grisebach, is dis-
tributed over the West Indies from Cuba and Jamaica to Trinidad,
and reaches the Spanish Main in Venezuela. Urban, who employs

FOREIGN DRIFT OF THE TURKS ISLANDS 147

for this species the synonym, Enallagma cucurhitina (BailL), adds
Panama to the hst of locahties (Symb. AntilL, IV., 567).

Gourds of Crescentia, more especially of C. cujete and C. cucurhitina^
characterised the beach-drift examined by me in Jamaica, Turks
Islands, and Trinidad. These three localities are sufficiently removed
from each other to justify the inference that Crescentia gourds are
generally characteristic of West Indian beach-drift. Numbers of
fruits both from the living plant and from the drift were examined
by me, and all of them belonged to this genus ; and the implication
arises that the gourds and calabashes carried by the currents from
the New World to the shores of Europe would be fruits of Crescentia.
The mode in which these fruits get within the influence of the currents
is well illustrated in the Black River district of Jamaica. Both the
trees named grow there at the riverside above the mangrove forma-
tion. Their fruits form regular constituents of the floating drift,
and are carried down to the sea in numbers, many of them being
subsequently cast up on the beaches in the vicinity of the estuary.

The next matter to be dealt with concerns the station of these
two species of Crescentia. The Calabash tree, C. cujete, occurs both
wild and cultivated in Jamaica ; but the natives distinguish the wild
trees at a glance by their smaller fruits and by other characters.
Grisebach supplies no station for the species; but Hemsley after
giving its general distribution states that it grows commonly in swampy
and marshy places (Chall. Bot., II., 55). It was in such stations that
I usually found the wild tree in Jamaica; but it also grows there in
the open woods of the lower levels. It came under my notice most
typically as a tree of the interior of the Great Morass of the Black
River district in this island, where it is associated at the riverside
amongst other trees with Grias cauliflora (Anchovy Pear tree). Both
Grias cauliflora and the Calabash tree, in bearing flowers and fruits
on their trunks, exhibit the same feature of " cauliflory." Sloane,
writing of the Calabash tree in Jamaica near the close of the seven-
teenth century, says that " it grows everywhere in the Savannas
and woods of Jamaica and the Caribes " (II., 173) ; but he makes no
reference to its being cultivated. Urban, speaking of its general
station in the West Indies, states that it grows in woods and is also
cultivated (Symb. Ant., IV., 567). That the tree can thrive in dry
stations is illustrated in the Virgin Islands, where it is associated
with Cactacece and other xerophilous plants (Harshberger's Phytogeog.
N. Amer., p. 687).

Crescentia cujete is readily propagated from shoots; and it is on
its powers of vegetative reproduction that the Jamaican cultivator
seems to rely, the seeds according to common report being useless
for the purpose. The fleeting vitality of the seeds is pointed out
below. Crescentia cucurhitina, the other species represented in West
Indian beach and river drift, is the " Paki " of the Jamaican. It
w^as observed by me as a tall tree growing on the banks of the Black
River above the mangroves, and also in wet ground near the coast
below the Roaring River Falls on the north side of the island.
Grisebach gives its station in Jamaica as the dry rocky coast. This
is rather puzzling, since it is essentially a tree that favours moist

148 PLANTS, SEEDS, AND CURRENTS

localities. Urban, alluding to its station in the West Indies {Ibid.,
IV., 567), states that it grows in marshy places, both inland and
at the coast.

The suitability of the fruits of these two trees for dispersal by
currents was especially studied during a sojourn at Black River in
Jamaica. That they could be thus transported across wide tracts
of sea soon became evident, and the point to be determined was
whether after being stranded on some distant shore they were likely
to contain germinable seeds.

The fresh gourd of Crescentia cujete is filled with a white spongy
pulp containing numerous seeds. After detachment of the fruit the
pulp soon begins to soften and blacken; and a process almost of
liquefaction sets in, which seems usually to involve the vitality of
the embryos of the inclosed seeds, unless conditions favouring rapid
germination intervene. As the fruit dries on the ground, its contents
ultimately dry up, and all that represents the original white pulp and
its seeds is a loose, rounded, blackened mass, about one and a half
inches across, in which the seeds may be observed either empty or
with embryos evidently dead, if not actually decaying. This is the
condition in which the fruits of the Calabash tree generally are
found in the Jamaican beach-drift, and anything less likely to
assist dispersal by currents, as far as the propagation of the species
is concerned, could scarcely be imagined. In these gourds of the
shore-drift, when the embryos of the seeds have not disappeared,
they are usually blackened, friable, and dead; whilst only in a few
cases are there any signs of vitality ; and even then the discoloured
appearance and general condition give but little promise of any
capacity for germination.

The gourds of Crescentia cujete, as found in the beach-drift of the
Black River district, were generally small, three to four inches across,
globose, much weathered by exposure, and in half of them the shell was
cracked. They were evidently derived from the trees growing wild
in the Great Morass by the riverside, and had been washed up on the
beaches after having been carried down to the sea. They came
under my notice on the beaches near the mouths of rivers in other
parts of Jamaica, as near the White River on the north coast. On
the beaches of the Black River district they were four times as
frequent as those of the Paki tree (C. cucurhitina). Their shells also
are thicker (2 mm. as against 1 mm.), and the fruits generally seem
better fitted for withstanding the buffeting involved in sea transport.

The fresh gourds of Crescentia cujete float in water, and in this
state they are not uncommon in the floating drift of the Black River ;
but their buoyancy is principally due to the spongy air-bearing pulp
and to the impermeability of the shell, the specific gravity of the
last being near that of fresh-water. The fruit acquires increased
buoyancy after the pulpy contents have broken down and dried
up into a small rounded mass, leaving the greater portion of its
cavity empty, such being its condition in the beach-drift. The fresh
moist seeds, 9 or 10 mm. long, have an initial buoyancy, a capacity
which they owe entirely to the fact that the embryo but loosely
fills the cavity within its horny coverings. When dry they at the

FOREIGN DRIFT OF THE TURKS ISLANDS 149

most float for only a day or two. Under any circumstances, how-
ever, the seed with its transient vitality, is quite negligible as an
independent agent in current-dispersal.

The fruit of the Paki (C. cucurhitina), which displays on its surface
numerous pin-point pits, is ovoid or oblong, three to four inches long,
with a blunt terminal point, its cavity being filled with a white, spongy
pulp containing numerous non-buoyant seeds, 16 or 17 mm. across,
and thus much larger than those of the Calabash tree (C. cujete).
The seed contains a reddish embryo within a loose, white, mem-
branous, sac-like covering; but as compared with the seeds of the
Calabash tree those of the Paki are poorly protected, shrink greatly
on drying, and are still more perishable in their nature. The fresh
fruit floats, and was not uncommon in the drift of the Black River.
As with the gourd of the Calabash tree its buoyancy is due to the
air-bearing pulp and to the waterproof shell. Here also the pulp
of the mature fruit soon undergoes a softening and blackening
process; and here again the pulp and seeds ultimately dry up and
cake into a loose, blackened, rounded mass occupying but little
space in the fruit cavity, the seeds being dead and their embryos
blackened and often friable. The Paki gourds thus appear to be
even less fitted for the distribution of the tree through the agency
of the currents than those of the other species. But apart from the
condition of the seeds the gourd itself is less able to withstand the
*' wear-and-tear " of oceanic dispersal, since the shell is thinner
(1 mm.) and more brittle than that of the fruit of the Calabash tree.
The fruits are also less frequent in the beach-drift of the Black River
coast than those of C. cujete. Their form, their pin-hole pits, and
their blunt terminal point, as well as their large seeds, readily dis-
tinguish them from the other gourds in the drift. They are described
by Miers in the Transactions of the Linnean Society, Vol. XXVI., 1870.

In the Turks Islands I found these two gourds to be regular con-
stituents of the larger foreign drift of the beaches, as on Grand
Turk, Cotton Cay, Greater Sand Cay, etc. Those of the Calabash
tree were rather more frequent than those of C. cucurbitina in the
proportion of three to two. Most of the former were the smaller
fruits of the wild tree ; but I also found one or two large calabashes
six or seven inches across, doubtless the fruit of the cultivated tree.
With both species the stranded gourds were much weathered and often
cracked ; and all that w^ere examined contained the usual dried-up,
blackened, loose mass of pulp and dead seeds. A good proportion,
however, had entire shells (perhaps half of them), and could have
continued their ocean traverse.

Since the plants do not grow in the Turks Islands, which derive
their foreign beach-drift from the islands to the southward and
eastward, we have here the completion of the first stage in crossing
the Atlantic. It is highly probable that some of these floating
gourds, more especially those of C cujete, are included at times
amongst the West Indian drift stranded on the shores of Europe.
But their seeds would be always dead ; and it could be only in local
distribution, as in inter-island dispersal, that currents could aid in
the spread of the species. The occasional presence of a solitary

150 PLANTS, SEEDS, AND CURRENTS

wild specimen of the Calabash tree amongst the vegetation bordering
the beaches on the Black River coast may be thus explained, the
parent gourd having been brought down by the river. My Jamaican
companions at once recognised them as wild, self-sown trees.

Andira inermis, Kth. (Angeleen tree)

This tree belongs to a genus of the Leguminosce, comprising about
twenty species, all of which are confined to the tropical regions of
the New World, with the exception of this species, which, according
to Grisebach, Oliver, and others, also occurs in Senegambia on the
West Coast of Africa. We learn from Grisebach that the Angeleen
tree is distributed over the greater part of the West Indies from
Cuba and Jamaica to Trinidad, and that it extends from Mexico
along the Spanish Main to Guiana.

Generally speaking it is a tree of the lower forests, but with a de-
cided inclination, determined by the buoyancy of its fruits, to gather
at the riverside. This preference for a station along the river banks
is remarked by Grisebach for the tree in Jamaica ; and it was in such
localities that I observed it in that island. The places in which it
was more particularly studied by me in Jamaica were along the
banks of the Black River above the mangroves, extending to the
foothills of the central range, and in the hilly country at the back
of St. Anne's. Its station by the riverside is the only fact connected
with its range that can be brought into relation with its occurrence
on the West Coast of Africa ; but this does not carry us very far.
Although the river could bring the fruits within the influence of the
ocean currents, there seems to be but little chance of their ever
being stranded on the African coast with their seeds in a germinable
condition. Since the genus is American, the New World must
have supplied the opposite coast of Africa with this American tree ;
and that could only happen now along the circuitous Gulf Stream
route. That a pod stranded on the eastern shores of the Atlantic
could contain a germinable seed, will appear from the following
discussion to be most improbable.

The fruit is a leguminous, indehiscent, one-seeded pod, about one and
a half inches long, ovoid-globose in form, with (in the dry state) a loose-
textured, fibro-ligneous husk 2*5 to 3 mm. thick. In the fresh con-
dition, when it is moist and semi-fleshy, it has but little buoyancy,
either sinking at once or floating only for a day or two; and thus
the pods form no feature in the Black River drift, though the tree
commonly grows on the banks with its branches overhanging the
stream. In the dry state they are evidently much more buoyant;
but the indications of my observations are that except in inter-
island dispersal in the West Indian region the fruits would rarely
contain a germinable seed when distributed by the currents. The
stranded pods did not come under my notice in the Jamaican beach-
drift ; but I gathered them in small numbers from amongst the foreign
drift thrown up on the beaches of different islands of the Turks
Group. Such drift fruits sometimes contained a seed; but it was
hard, discoloured, and evidently unfit for germination. Since the

FOREIGN DRIFT OF THE TURKS ISLANDS 151

seed had no buoyancy, the pod must have owed its floatinjr power
to the hght, loose-textured husk. There is httle to show that the
dry fruit would remain watertight for any length of time when
immersed in sea- water. The only protection the seed itself possesses
against the influence of sea- water is a thin permeable skin; and I
think that the death of the seed of the floating fruit would soon be
brought about through this cause. The pods probably reached the
Turks Islands after a week or two's drift from the neighbouring
coasts of San Domingo.

For the reasons just given it would seem futile to look to the currents
for the explanation of the existence of this tree on both sides of the
tropical Atlantic. We have seen that since the West African region
must have borrowed this species from the New World, we are debarred
from appealing to the agency of the Equatorial Current in transport-
ing seeds and fruits from the Gulf of Guinea to the American conti-
nent. There remain only the possibilities of its reaching West Africa
by the westward extension of the Guinea Current or with the Gulf
Stream drift after it has crossed the North Atlantic. As shown in
Chapter III., the first route receives but scant support from the
evidence of bottle-drift, and the time required (at least six months)
would negative its practicability for the effective dispersal of this
tree. The objections would be still greater if we appealed to the
second route, which would involve an ocean passage of about two
years. In addition it is most unlikely, if plants like Sacoglottis
amazonica and Hippomane mancinella, which are so much better
fitted for the Atlantic traverse, have failed to get away from America,
that a plant with the limited fitness for dispersal by currents
possessed by Andira inermis should be able to do so.

Thus the currents fail to account for the occurrence of this tree
on the coast of West Africa. But it is just possible that the light,
empty pod might occur at times amongst European beach-drift, as
it would probably continue to float long after it had ceased to be
watertight. The great difficulty lies with the ill-protected seed.
Under natural circumstances its germinative capacity would soon
be lost, since the thin coats offer no protection against excessive
shrinkage, and it would seem likely that ordinary air-drying would
soon deprive it of vitality.

Birds also fail us, since only a fruit-pigeon could carry such a
large fruit, and that would only be possible between neighbouring
islands or between adjacent insular and continental coasts. The
difficulties here raised resemble in some points those presented in
the case of the fruits of Chrysohalanus icaco, a plant also found on
both sides of the tropical Atlantic (see p. 193). But there is this
important difference in station. With the species of Chrysohalanus
the tree. is essentially littoral, and thus the currents when carrying
the fruits to a distant coast would be bearing them to a suitable
station. With Andira inermis, however, the stranded fruits would
lie in most uncongenial conditions, conditions very different from
those which the tree favours in inland districts, as in the humid
forests of Porto Rico (Harshberger, pp. 685, 688) or by the riverside
in Jamaica.

152 PLANTS, SEEDS, AND CURRENTS

Cassia fistula, L., and Cassia grandis, L.

The pods of these two trees, which are often two feet long in the
entire state, are characteristic of the foreign drift on the beaches of
the Turks Islands, though in a fragmentary condition. I found
them on the beaches of all the larger cays, such as Grand Turk,
Cotton Cay, Salt Cay, and Greater Sand Cay. Portions of the same
two fruits also came under my notice amongst the beach-drift of
Trinidad and Tobago. The association of the pods of these two
trees in the beach-drift of the West Indian region in localities so far
removed from each other is worthy of remark. Those of Cassia
■fistula were also recorded by Morris from the stranded drift in
Jamaica (ChalL Bot., IV., 301). We must therefore regard these
singular fruits as regular constituents of West Indian beach-drift.
Their occurrence in this connection on the Turks Islands is specially
interesting, since the trees do not grow in those islands, and the pods
could only have been brought by the currents from the large islands
to the southward and eastward. On these beaches the pods of
Cassia grandis are more frequent than those of C. fistula.

Since Nature associates these two trees in the drift, we will deal
with them together. Cassia grandis is indigenous in tropical
America and in the larger West Indian islands (Grisebach). It is
one of the several species of the genus that represent the remains of
the original Antillean flora of the great Caribbean land-mass now in
large part beneath the sea (Harshberger, Phytogr, N, Amer., p. 307).
But Cassia fistula is usually regarded as introduced to America from
its home in the Old World, although the matter is still one for dis-
cussion. However, from the facts given by Sloane, to be subse-
quently noticed, there seems little room for doubt that with Cassia
fistula in the West Indies we are concerned with an introduced tree.
De Candolle held with Sloane that it was brought by the Spaniards
to America (Geogr. Bot., p. 772) ; and both Bentham and Grisebach
regarded it as naturalised in the tropics of the New World. A good
deal of interest attaches itself to this point, since the pods of Cassia
fistula are amongst those found on the coasts of Europe with other
West Indian drift.

But before proceeding further in this discussion I will refer to the
condition of the fruits of these two trees as presented on the Turks
Islands beaches. The seeds, it should be remarked, have no buoyancy,
being transported in the compartments of the buoyant pod ; but the
long fruits break up in time in the floating drift, and though sea- water
then penetrates some of the compartments, the fragments still float,
being kept up by the air confined in the other chambers and by the
buoyancy of the tissues forming the fruit. It is in this fragmentary
state that these pods usually occur in the Turks Islands beach-drift,
and also in that of other West Indian islands, the portions varying
from four to ten inches in length and being as a rule much " weathered."
The smooth pods of Cassia fistula are, however, much better fitted
for ocean transport than those of C. grandis^ which have a rougher
exterior and possess two lateral ribs that are very apt to be torn
away in the drift, thus exposing the seed-chambers along more or

FOREIGN DRIFT OF THE TURKS ISLANDS 153

less of the fruit's length. Yet most of the seeds are too large to fall
out of the pod at first; but the waves would soon complete the
process of destruction, and the floating pod, with long rents in its
sides, would probably not survive more than a month or two's
buffeting in the currents. Only the pods of C. fistula would be able
to withstand the " wear-and-tear " involved in the passage across
the Atlantic to the shores of Europe. It is, therefore, at first sight
not surprising that they alone have been found stranded on European
beaches.

But before dealing with this matter, I will refer to the condition of
the seeds in the fruits thrown up on the beaches of the Turks Islands,
which represent the end of an early stage in the transatlantic
voyage. Most of the seeds of these two species of Cassia are im-
permeable to water, and they would withstand for a long time the
effects of the penetration of sea- water into the floating fruit, which
takes place sooner or later when the long pods, as generally happens,
break in two. Those that are permeable would quickly swell up and
lose their germinative capacities; whilst in time a number of the
impermeable seeds would be also unable to retain their impervious
character under the warm, moist conditions of the drift in tropical
seas, and they, too, would swell up and become useless for propagat-
ing purposes. But a good proportion of the seeds would be able for
long periods to resist the penetration of sea-water, and transported
in the floating fragments of the pod they would retain their sound
state when stranded on some distant coast. Of the seeds found in
the fragments of the pods of C. fistula and C. grandis on the beaches
of the Turks Islands, between 20 and 40 per cent, were generally
hard, entire, and quite sound on section; the rest had lost their
germinative powers, having swelled up after the sea-water had
penetrated the drifting fruit.

The fragments of the pods of these two trees that are stranded on
the Turks Islands could at the most have only drifted a few hundred
miles, and seeing that more than half of their seeds have been killed
by the penetration of sea-water, it seems unlikely that many sound
seeds would be found in the pods of Cassia fistula that have been
picked up on European beaches. I am assuming here that such
fruits hail from the New World, which at first appears reasonable,
since they are associated in the European beach-drift with seeds of
Entada, Guilandina, Mucuna, etc., that undoubtedly come from the
American side of the Atlantic.

It would seem, however, that the records of the stranding of the
fruits of C. fistula on the European side are not numerous. Accord-
ing to Sernander (p. 117) they were found on the Norwegian coasts
by Strom and Gunnerus, who flourished about the middle of the
eighteenth century. Lindman in recent years has confirmed the
identification of the species (Sernander, Ibid.). In this matter
Hemsley (Chall. Bot., IV., 277) quotes Tonning, a pupil of Linnaeus,
through whom the observations of Strom and Gunnerus, as Sernander
points out (p. 116), are usually known in the scientific world.
Nothing, however, is said by Sernander as to the condition of the
pods and of the seeds when gathered on the Scandinavian beaches.

154 PLANTS, SEEDS, AND CURRENTS

Much depends on these points, since fruits that were entire and
showed but Httle signs of long exposure to the sea could scarcely
have accomplished the passage from the New World.

It is interesting to note the fact referred to by Hemsley (ChalL
Bot.y IV., 278, 301) that Martins raised plants from seeds of Cassia
fistula cast ashore in the pod at Montpellier in the south of France.
Hemsley cites this case as one of the instances where plants have
been raised in Europe from seeds that have traversed the Atlantic.
On this view the pod must have been carried through the Straits of
Gibraltar into the Mediterranean after its ocean traverse. Here,
again, much would depend on the condition of the stranded fruit
when determining its probable source. It would seem safer, indeed,
to look for a source much nearer home than the American side of the
Atlantic ; for instance, in Egypt, where the tree has long been widely
spread, since such pods might have been brought down to the sea in
the Nile drift. At all events, the observations of Martins at Mont-
pellier and of myself in the Turks Islands indicate that the pods of
Cassia fistula can carry sound seeds across considerable tracts of
sea; but the data at my disposal, whilst indicating the possibility
that the pods can be transported from the New World to the shores
of Europe by the currents, leave the question as to the condition of
the seeds unanswered. There is a lack of information concerning
the actual facts recorded, and for this reason a suspension of judgment
may be necessary.

It should be remarked that whilst the pods of Cassia fistula are
characteristic of West Indian beach-drift, there seems to be but
little mention of their occurrence in the drift of tropical beaches in
the Old World. Let us take, for instance, the Indian Archipelago
in its most comprehensive sense as including the whole region between
south-eastern Asia and Australia. This region is regarded as one of
the principal homes of the tree, and yet its fruits seem rarely to have
attracted the notice of observers of the drift. Thus they are not
named in Gaudichaud's description of the drift of the Molucca Sea
as quoted by Hemsley (Ckall. Bot., IV., 279). Schimper does not
mention them in his account of the drift of the Java Sea and of the
coasts of Java (p. 160). In my own paper on the drift of Keeling
Atoll and of the south coast of Java no reference is made to them ;
and the same remark applies to the writings of Treub, Penzig, and
Ernst on the new Krakatau vegetation, and to Moseley's account of
the drift observed by the Challenger Expedition off the coast of New
Guinea, as given by Hemsley {Ibid., IV., 285). It is possible that
such fruits may have been at times regarded in the same light as
the empty mango stones so frequent in tropical beach-drift, but this
seems hardly likely.

The divergence in opinion relating to the claim of Cassia fistula to
be ranked as an indigenous American tree is illustrated by Hemsley.
Whilst in one place he includes it amongst those plants certainly or
probably dispersed by currents, in another place, when dealing with
Jamaican beach-drift, he writes that it doubtless owes its present
wide area to man rather than to any other agency (Chall. Bot., I., 43;
IV., 301). It is odd that its pods are a feature of tropical beach-drift

FOREIGN DRIFT OF THE TURKS ISLANDS 155

in the New World rather than in the Old World; and it would
almost seem that Nature in the form of the Gulf Stream drift,
stranded on the shores of Europe, makes a silent protest against our
viewing this tree as a stranger in America.

There is, however, a way out of the difficulty. It is possible that
Cassia fistula may have been the gift of Africa to America through
the agency either of the Main or of the North Equatorial Current
before the discovery of the New World, but in the earlier period of
the European colonisation of West Africa. In the first case the
floating pods could have been transported in two or three months
from the Gulf of Guinea to Brazil, and no doubt many of the seeds
would still be sound. In the second case, where the agency of the
North Equatorial Current is appealed to, the floating pods could
have been carried in six or seven months from the vicinity of the
Cape Verde Islands to one of the Lesser Antilles, and perhaps a few
of their seeds would still be germinable. The intervention of the
aborigines of the New World would be required ; but one can imagine
that the discovery of such a singular fruit on the beach might tempt
one of the more curious among the natives to plant its seeds. The
tree must have been long established on the West Coast of Africa and
on the Cape Verde Group. In those two localities in the middle of
last century it was beginning to grow wild (Schmidt's Cap Verdische
Flora, 1852).

Though it is feasible that Cassia fistula may have been introduced
into South America by the currents, assisted, as just suggested, by
the subsequent intervention of the aborigines, it can hardly be
doubted that the early Spaniards were the agents in establishing it
in the West Indies. Sloane in his book on Jamaica (II., 42) quotes
Martyr to the effect that it was planted in Hispaniola, Cuba, and
Jamaica by the Spaniards. Sloane was writing of his experiences
in the latter part of the seventeenth century, when, as he indicates,
there was a trade to Europe from the New World in the fruits of
this tree, the Brazilian fruits being regarded as superior to those
from Egypt. In 1688-9, during his sojourn in Jamaica, the tree
was frequently to be met with around houses and on the sites of
plantations during the Spanish time. He takes the similar history of
the Tamarind (Tamarindus indica), which, having been first planted
at Acapulco by the Spaniards, was in his time widely spread over the
West Indies. The case of the Tamarind appears to be decisive in
this matter.

Calophyllum calaba, Jacq.

This West Indian and South American tree, with which I made
my first acquaintance in the forests of Mount Diavolo in Jamaica,
calls for only a few remarks. It contributes scantily to West Indian
beach-drift ; but it cannot be compared, either in its station or in the
buoyancy of its fruits, with Calophyllurn inophyllum, the well-known
current-dispersed tree of the coral atoll and of the coral-girt shores
of the Pacific.

Calophyllum calaba, the familiar Santa Maria tree of the West
Indies, is a conspicuous feature of the wet forests of Jamaica and

156 PLANTS, SEEDS, AND CURRENTS

Cuba. It would only be found near the beach when forested hill-
slopes descend directly to the coast. In Jamaica it is certainly not
a littoral tree, and this is also the view of Grisebach. However,
Descourtilz, as quoted by Hemsley (Chall. Bot., IV., 298), and
Schimper (Ind. Mai, Strand Flora, pp. 108, 182) speak of it as a
West Indian strand tree.

I found a few of the small globular fruits amongst the beach-drift
of the north and south shores of Jamaica, some of them empty and
some of them bearing sound seeds. Fruits with sound seeds were
picked up by Morris on the south coast of the island (Hemsley,
Ibid.). The manner in which its buoyant fruits could reach the sea
is indicated in the station of the tree on the banks of a branch of
the Spanish River in the mountain forest zone of eastern Jamaica
(Forrest Shreve in Harshberger's Phytogr. N. Amer., p. 679). I
collected a few of the fruits amongst the foreign drift of the beaches
of the Turks Islands, but they were either empty or contained a
greatly shrunken dead seed.

If this was a typical strand tree in the West Indies, with its fruits
dispersed far and wide by the currents, we should expect it to play
the part taken by Calophyllum inophyllum in the Pacific, as above
referred to. We should expect to see it establishing itself on the
sandy islets thrown up in coral-reef regions, as on the Florida sand-
keys, and to find it included amongst the indigenous flora of a group
like the Bermudas. Dr. Millspaugh does not mention it in the case
of the Florida keys so systematically examined by Mr. Lansing;
whilst it is admitted to be an introduced plant in the Bermudas,
and apparently it belongs also to the foreign plants of the Bahamas
(Chall. Bot., II., 21 ; IV., 298).

Hemsley regards it as dispersed by the currents {Ibid., I., 42) ; and
this is the opinion also of Schimper, who couples C. inophyllum and
C. calaba together as possessing a well-developed floating apparatus
in the shell of the fruit (p. 182). But whilst Nature has emphatically
demonstrated that the first is dispersed by currents far and wide
over the insular and continental coasts of the Indian and Pacific
Oceans, she gives no consistent indications of the same kind for the
second. In Jamaica and Cuba, C. calaba is essentially a tree of the
inland forests, and its fruits make a very poor show in the beach-
drift. Although it is possible that the currents might carry the sound
fruits to a distant shore, it is scarcely likely that a tree accustomed
to the humid conditions of an inland forest would be able to establish
itself on a beach. However, the germinative capacity of the seeds
appeared to be soon lost ; and in an experiment on the buoyancy of
the dry fruits I found that whilst they all floated for two or three
weeks, those that floated for a longer period had rotting seeds. I
would imagine that, as compared with the Pacific species, the fruit-
shell is more pervious to water in prolonged flotation.

Sapindus saponaria, L. (Soap-berry)

This is an American tree usually described as confined to Florida,
the West Indies, and Venezuela. A specimen obtained by Forster

FOREIGN DRIFT OF THE TURKS ISLANDS 157

from Easter Island about 1773 was regarded by Seemann in his
Flora Vitiensis (p. 47) as belonging to this speeies; and there would
seem to be some reason for believing that the species is indigenous
in the Marquesan and Tahitian Groups, in the floras of which it is
included by Drake del Castillo in his work on those islands. Both
Hawaii and Fiji have each a peculiar species; but I would refer the
reader to my book on Plant Dispersal (pp. 325, 332) for an account
of the difficulties connected with the distribution of the genus, and
to Hemsley's remarks in the Botany of the Challenger Expedition
(IV., 304) for an authoritative discussion of this point. If, as Hemsley
observes, there are two or three Asiatic species closely allied to
Sapindus saponaria, it may be that we are here concerned with one
variable plant that ranges through the warm latitudes of the globe.
In any case we are here dealing with a plant that is well worth
studying from the standpoint of dispersal.

Although, as stated below, the seeds of Sapindus saponaria have
been found in the stranded drift of Jamaica, the Turks Islands, the
Bermudas, and the Azores, it does not seem to be a littoral tree in the
ordinary sense. Schimper (Ind. Mai. Strand Flora, p. Ill) remarks
that it ought to be a strand plant in the New World ; but Grisebach
gives no particulars as to its station, and I did not observe it amongst
the shore vegetation in Jamaica. Writing of the tree in Jamaica,
Sloane observes (II., 132) that it grew in his time in all the " lowland
or Savanna woods " of the island. It is, indeed, a tree of the open
woods; and this is also the station assigned to it by Millspaugh in
the case of the island of Cozumel, off the coast of Yucatan (Plantce
JJtowance), From such a station its seeds would at times get into
river-drift and be carried to the sea. In those seemingly rare
localities, where as an intruder from the inland districts the Soap-
berry tree grows by the beach, the dispersal of its buoyant seeds by
currents would be facilitated. This would be the case in Florida,
where, as Prof. Harshberger tells me, the plant grows on the sandy
beaches of the peninsula.

An interesting record of the occurrence of the seeds of this tree in
beach-drift is that described by Hemsley, on the authority of J. M.
Jones, in the case of the Bermudas (Chall. Bot., II., 27; IV., 304).
The plant is rare in those islands, having been first raised from seed
washed up on the southern shores in 1841. It must thus be viewed
only as a recent addition to the Bermudian flora ; but the important
point is that the seed preserved its germinative powers after a period
of flotation in the sea that must have covered several weeks, if not
months, though man's aid was necessary to secure the establishment
of the species. A few seeds came under my notice amongst the drift
stranded at Paroti Point on the south coast of Jamaica. Though
the tree is common in the island, this was the only locality in which
I found the seeds in the beach-drift. The seeds examined had sound
kernels and floated in sea-water. I picked up two others amongst
the stranded drift on Greater Sand Cay, the southernmost island of
the Turks Group; but they were afterwards mislaid, so that their
soundness was not tested. Though occurring in scanty numbers,
the seeds of Sapindus saponaria may, I think, be claimed as one of

158 PLANTS, SEEDS, AND CURRENTS

the normal constituents of West Indian beach-drift. I found no
reference to their occurrence in European beach-drift ; but, as stated
below, they came under my notice amongst the foreign drift of the
Azores.

The modes of dispersal now merit our attention. Although the
fleshy pericarp of the fruits might attract birds, the seeds in their
hard shells being apparently well able to withstand transport in a
pigeon's crop without injury, there is no evidence at my disposal
that frugivorous birds distribute the seeds. On the other hand, the
indications of West Indian beach-drift and the stranding of the seeds
in a germinable condition on the shores of Bermuda point unmis-
takably to the agency of the currents. Hemsley's view that the
seeds are dispersed by the currents (Chall. Bot., I., 43, 48; II., 27;
IV., 304) is thus well founded, and the behaviour of the seeds under
experiment in part confirms his opinion.

The seeds are black, round, 10 or 11 mm. in diameter, and
have a hard, impervious shell about 1 mm. thick. The buoyancy
is of the type characteristic of convolvulaceous seeds, neither the
shell nor the kernel possessing any floating power of themselves, the
buoyancy arising from the fact that the kernel incompletely fills
the seed-cavity. When, however, the cavity is entirely occupied, the
seed sinks. Thus it happened that in my experiments in Jamaica
about half of the seeds sank at once in sea- water, and about three-
fourths of them sank in fresh-water. Of those that floated in sea-
water about half floated after a month's immersion, and 20 or 25
per cent, after six to seven weeks, some of the last being sound,
whilst in others it was evident that water was beginning to penetrate
the coverings. The weak spot in the hard shell is in the " scar,"
the umbilical aperture previously closed tending to become patent
after prolonged immersion. Water finds its way slowly into the
interior, the hard shell softens so that it can be readily cut with a
knife, the kernel decays, and the seed sinks. When several seeds
are kept in the same vessel the water has to be changed frequently,
as the rotting kernels of the seeds that are absorbing water turn it
putrid.

I would imagine that few seeds would display sound kernels after
more than two months in sea-water. This period, however, might
be sufficient for the transport of some of the seeds in a sound con-
dition to Bermuda from the Florida Strait; but it would be in-
sufficient for their passage to the Azores, for which several months
would be necessary (see Notes 12 and 14 of the Appendix). Though,
as far as I know, the seeds have not been found on European beaches,
their occurrence on the beaches of the Western Azores points, in
spite of the results of my experiments, to this possibility. I picked
up two seeds, both seemingly sound, one at Porto Pym in Fayal, and
the other near Magdalena at the west end of Pico. But even the
presence of these drift seeds in the Azores is inconsistent with the
indications of the experiments. Additional investigations are needed
before one can credit these seeds with the capacity of reaching isolated
islands like Easter Island through the agency of the currents.

FOREIGN DRIFT OF THE TURKS ISLANDS 159

Drepanocarpus lunatus, Mey.

This shrub grows in maritime swamps in the tropics of the New
World and of the West Coast of Africa, being in both regions often
associated with the mangroves, and especially on the African side,
where, as we learn from Dr. Vogel's journal (Hooker's Niger Flora,
1849), it is frequent at the coasts and in the estuaries. According
to Grisebach it is found on the mainland of the New World from
Mexico to Brazil, and he records it from the West Indian islands of
Haiti, St. Lucia, and St. Vincent. In West Africa it thrives on the
Guinea Coast and in Senegal.

With the exception of a solitary empty pod that came under my
notice on one of the beaches of the Turks Islands, I never found the
fruit represented in West Indian drift, nor was it represented in the
collection of Jamaican beach-drift made by Morris. It is therefore
probable that neither the fruits nor the seeds are suited for effective
dispersal by currents. Yet the opposite inference might be drawn
from the fact that out of about fifteen known species of the genus
only one occurs outside the New World, namely Drepanocarpus
lunatus, and that is held in common between West Africa and
America. De Candolle considered that this littoral species might be
spread by the currents, but gives no data. In his Geographie Botanique
(1855, circa p. 780) he viewed it as an American plant naturalised
in West Africa ; and with it he links Ecastaphyllum brownei, another
littoral plant that is both West Indian and West African, yet is
unsuited for trans-oceanic dispersal by currents (see p. 207). This
seems to be an unsatisfactory explanation. If valid, we should have
to apply it to other littoral plants, e. g. Symphonia globulifera,
which present precisely the same difficulty (see p. 243).

Omphalea diandra, L.

The seeds of this euphorbiaceous plant must be regarded as typical
of West Indian beach-drift. They are black, semi-globose, one to
one and a half inches across, and possess a hard, crustaceous shell.
Whilst scantily represented in the Turks Islands drift, they are
characteristic of the Trinidad beaches ; and they are included in the
collection of drift made by Morris on the coast of Jamaica (Chall.
Bot., IV., 302). But though about half of those collected by me on
the West Indian beaches contained kernels, the others being often
more or less empty, it is uncertain whether any of them would
retain their germinative capacity after prolonged flotation in sea- water,
the oily kernel being liable to a degenerative change that destroys
its viability after being kept for a year or two. The kernel removed
from its impervious hard shell floats in water, its buoyancy being
due mainly to the lightness of the albumen, but partly also to a
shrinkage-cavity between the cotyledons. It is thus apparent that
the seeds, which must often be carried down by rivers to the sea,
could be transported by the currents for considerable distances ; but
it is very doubtful whether this would aid the oversea dispersal of a
riverside inland plant such as Omphalea diandra undoubtedly is.

160 PLANTS, SEEDS, AND CURRENTS

I am not acquainted with the parent plant; but Hemsley states
that it cHmbs on trees on river banks in Central and South America
and in the West Indies (Chall. Bot., IV., 302). Pax, in the Pflanzen-
reich monograph on the Hippomanece (IV., 147, 1912), to which the
genus is referred, states that the distribution of this species extends
from the Antilles and Central America to Peru and Brazil. It is
found in the Amazon region, and here one may note Spruce's observa-
tion of its frequency amongst the riverside vegetation of one of the
tributaries of the Maranon branch of the Amazon on the lower
eastern slopes of the Ecuadorian Andes (Kew Bulletin, 1909, p. 216).

Omphalea triandra, another species, which is dealt with on p. 226,
contributes to local beach-drift in the West Indies. Although the
seeds float and illustrate the same type of buoyancy, they lack the
hard crustaceous shell of those of O. diandra, and are in this respect
less fitted for prolonged transport by currents.

ACROCOMIA

The empty " stones " of this genus of palms are common in
Jamaican beach-drift, and also came under my notice on the beaches
of Trinidad, Tobago, and Grenada, being doubtless in the main
derived from trees growing in the interior of the respective islands.
They may be regarded as characteristic of West Indian beach-drift,
though they are very scantily represented in the foreign drift of the
Turks Islands. Yet it is not easy to explain at first sight their
occurrence on beaches, since the palms especially affect savannas
and open woodlands, and seem to have no special preference for the
vicinity of rivers, by which the fruits could be conveyed to the coast.
However, that they are thus carried down to the sea is very evident.
(I have not distinguished here between the fruits of the two most
common species of the genus, A. lasiospatha and A. sclerocarpa).

The moist mature fruits sink in sea-water, but they acquire
buoyancy in the drying process. However, experiment shows that
the dry fruits will sink in a few days or in a week or so, the outer
brittle shell being deficient at the base, which is imperfectly pro-
tected against the penetration of water by the small perianth. The
history of these fruits in West Indian drift is similar to that of
Aleurites moluccana in the drift of the Pacific islands, as described in
my book on Plant Dispersal (p. 419). The fallen fruits, having
become light and buoyant in the drying process, are washed into the
rivers and thus transported to the coast, where they are often
stranded on the beaches. Whilst lying there exposed to the sun and
rain, they are in time deprived of their outer coverings. The hard
black " stones," about an inch across, which are thus exposed, soon
lose their seeds through decay, and it is in this condition that they
usually occur in the beach-drift. The seeded " stone " has no
buoyancy either in the moist or the dry fruit. It is only when it
is set free by the removal of its coverings on the beach, and when
it has lost its seed by decay, that it is able to float. Each empty
*' stone " has three lateral perforations, two of which are closed at
the bottom, but one is more or less patent. However, the sea- water

FOREIGN DRIFT OF THE TURKS ISLANDS 161

is unable to displace the air within, and the " stone " thus becomes
buoyant.

Ipomcea tuberosa, L.

Much interest is attached to these West Indian drift seeds or
fruits, since they remained for nearly three centuries without a
botanical name, though often mentioned by the earlier botanists
and other contemporary writers as figuring amongst the foreign
drift stranded on the Orkney Islands and the Hebrides. Clusius
(1605), C. Bauhin (1623), Sloane (1695), Petiver (1702), the two
Wallaces in their descriptions of the Orkneys (1693-1700), and
Pennant in the account of his tour in the Hebrides (1772), all refer
to them, but not one of them was acquainted with their source,
although some, like Sloane, make correct surmises. They were
content to describe and sometimes rudely figure them. Petiver' s
use of the name " Faba Orcadensis," though very appropriate in a
popular sense, since the earliest recorded drift specimens came from
that group, served rather to increase the mystery, which was not
solved until Hemsley identified them with Ipomcea tuberosa, L., in
his paper in the Annals of Botany for 1892 (Vol. VI.). Superstition
played its part in the story of these strange-looking gifts from the
sea; and, as we have seen in Chapter II., the women of the Hebrides
are stated to have sought relief during the pains of childbirth by
clenching one of them in the hand.

These fruits or seeds (their particular designation being uncertain))
are about an inch across, depressed-globose in shape, yet slightly
squarish in outline. The ebony-black hue, the hard, bony, polished
shell, the four-lobed, or rather four-grooved, upper surface, and the
large scar underneath, are characters that distinguish them from all
other drift seeds and fruits. Grisebach states that Ipomoea tuberosa
is distributed over the West Indian islands and occurs on the tropical
American mainland (Mexico to Guiana), as well as in tropical Africa
and the East Indies. Hemsley in the paper above named remarks
that although it is usually regarded as a native of tropical Asia,
Africa, and America, its Old W^orld form was separated by Mr. C. B.
Clarke under the name of /. kentrocaulos. "It is not " (he writes)

essentially a shore plant, but rather a climber of lofty trees." Nor-
mally there are four separable seeds as in typical Ipomoeas, but
they are closely compressed and form a spheroid. Not infrequently,
according to Hemsley, only one seed is developed, which " assumes
the size and nearly the shape of the four seeds combined," and
adapts itself to the size and shape of the seed-vessel, the original
complement of four seeds being indicated by four furrows. It may
happen, as in the case of one of the typical drift specimens examined
by me, that there is an appearance of two cells, each containing an
embryo. Here we seem to be concerned with a fruit rather than
with a seed. There is evidently much to be learned about the con-
ditions under which this abnormal development takes place. It
may be added that Grisebach makes no allusion to it in the descrip-
tion he gives of the species, and that seeds gathered by me from living
plants in Jamaica displayed no such peculiarity.

M

162

PLANTS, SEEDS, AND CURRENTS

A remarkable feature is that only these abnormal seeds or fruits
show capacity for dispersal by currents, the ordinary separate seeds
from Jamaican plants exhibiting little or no buoyancy. The current-
dispersed seeds, as we learn from Hemsley, are " not uncommonly
met with in the drift of the Caribbean Sea, and are sometimes carried
far up into the North Atlantic by the Mexican Gulf Stream." How-
ever, only two specimens came under my notice on West Indian
beaches, one in Jamaica and the other in the Turks Islands. They
are represented in the Kew Museum in the Morris collection of
Jamaican seed-drift made in 1884 ; but they were not mentioned by
Hemsley in his account of the seeds and fruits there contained which
is given in his report on the botanical results of the Challenger
Expedition (IV., 284, 298, 1885). Some years passed before he
identified them as the seeds of Ipojncea iuberosa.

The botanical name, however, was not kno"v\Ti to me until early in
1913, when Dr. Rendle very kindly came to my aid and referred me
to Mr. Hemsley's identification. Shortly afterwards I saw them
under this name in the Kew Museum, a note on the label stating that
they are frequently washed up on the coasts of Cuba and South
America. The interesting feature in the story of these West Indian
drift seeds is their occurrence on European beaches. In 1908 Mr. J.
Fox sent one to me from the Shetland coasts, together with seeds
•of Entada scandens and Mucuna ; and there is one in the Kew
Museum which was obtained by Colonel Fielden in the Hebrides in
1891. Doubtless these seeds have also been gathered amongst the
Atlantic drift on the shores of Scandinavia ; but Sernander makes no
allusion to them in his account of the foreign seeds and fruits washed
up on those beaches. However, it is possible that some large drift
seeds discovered there by Lindman in 1880, which were referred to
the Convolvulacece but had otherwise defied determination, may
belong to this species.

It came as a surprise to me, whilst looking up some of the early
references to Gulf Stream drift in the British Museum library, that
these seeds had long been known to the older botanists and to the
early writers on the Orkney Islands. In their nameless condition
.they were almost forgotten until Hemsley ■s\Tote his paper in the
Annals of Botany, The historical side of the subject did not, how-
■ ever, come within the scope of his paper; and this must be my
•excuse for dealing here with a matter that could have been handled
by him in a far more authoritative and complete fashion. The list
of references now given is not at all exhaustive, but it will serve my
purpose.

Clusius, in his Exoticorum Lihri (libr. II., cap. xvi., p. 41, fig. 9),
published in 1605, described and figured without further comment
these fruits amongst some which had been given to him by Jacobus
Garetus. C. Bauhin, in his Pinax Theatri Botanici (p. 405), printed
in 1623, merely cites the description of Clusius. With the aid of
Clusius, Sloane was able to identify the fruit with one of those
figured by the Rev. J. Wallace in his book on the Orkney Isles
(issued in 1693) amongst other " strange beans " frequently cast
up on those islands (Philos. Trans., Vol. XIX., p. 398, 1695-7);

FOREIGN DRIFT OF THE TURKS ISLANDS 163

and he also identified it with others he had often seen in collections
of rare fruits. Though, as he says, authors were silent as to its
source, and he himself had " never seen it grow," he rightly sur-
mised that the sea had brought it to the Orkneys from the West
Indies. The peculiar form of the fruit often tempted the old authors
to make a drawing of it. Though the figures are rude, they are
accompanied by good descriptions.

J. Petiver, F.R.S., a contemporary of Sloane, described and
figured the fruit in his Gazophylacium Naturce, a remarkable work
containing 1000 illustrations of objects of natural history, and pub-
lished with varying form and title from 1695 to 1764. Under the
name of Faba Orcadensis, he describes it as " nigra, polita, tetra-
sulcata, hilo magno," and, like Sloane, he refers to Clusius in this
connection. Like Sloane, also, he alludes to its being figured in
Wallace's account of the Orkney Isles, though in this case it is the
son's enlarged book that is concerned. " My ingenious friend,
Mr. James Wallace, Physician " (thus Petiver writes), " hath figured
this in his Description of the Orckney Isles ^ p. 14, from whose shoars
Mr. Will. Clerk brought it me. Father Kamel hath also sent me
the same from the Philippine Isles." [Petiver's description of the
fruit is given in a small octavo volume published in 1702, p. 54;
whilst the figure it concerns is to be found in a large folio volume
(table 34, fig. 10) issued in 1764, the contents of the first fifty tables
being described in the smaller volume. It is ill-figured, but well
described.]

It is evidently to this fruit that Pennant alludes in his account of
his Voyage to the Hebrides in 1772, which has been already quoted
(see p. 32). After naming four kinds of " Molucca Beans " thrown
up on this group, he says that " the fifth is a seed called by Bauhin
""fructus exot: orbicularis sulcis nervisque quatuor,^ whose place is
unknown." He appears to have had access to Sloane's account of
the West Indian drift seeds on the Orkney Islands ; but there is no
reference to it. C. Bauhin's Pinax Theatri Botanici (1623, p. 405) is
evidently the work quoted by him ; but Bauhin, as previously stated,
had merely quoted the earlier work of Clusius.

This discussion may be concluded with a few remarks on the
nature and cause of the buoyancy of these " composite " seeds, as
one might term them. Of the three specimens obtained from the
beach-drift of Jamaica, the Turks Islands, and the Shetlands, all
floated in sea-water, but two, including the Shetland seed, sank in
fresh-water. In other words, all were specifically lighter than sea-
water, but two were heavier than fresh-water. This behaviour,
interpreted in the light of a somewhat extended acquaintance with
the subject of the flotation of fruits and seeds where the average
specific weight happens to be near that of sea-water, indicates that
a large proportion of these " composite " seeds produced by the
plant would not possess buoyancy in any sense. As in the case of
convolvulaceous seeds generally, the floating power is to be ascribed
entirely to the cavities produced by the shrinking of the albumen
and embryo during the hardening stage, the separate parts having
no independent floating capacity.

164 PLANTS, SEEDS, AND CURRENTS

A section of one of the seeds disclosed traces of two cells, each
holding an embryo and displaying a large shrinkage- cavity.

Mangifera indica (Mango)

The empty fibro-membranous " stones " of this fruit are common
on the beaches of the Turks Islands and in West Indian beach-drift
generally. I would imagine that those washed ashore on the Turks
Islands were drifted there from San Domingo or were thrown over-
board from passing vessels. Numerous small craft hailing from San
Domingo and other islands trade in fruit in these seas. These
materials are found all over the tropics on the beaches of countries
where the Mango is cultivated. No doubt they often occur on other
coasts derived from rubbish thrown over by passing ships. Prof.
Ewart tells me that they are cast ashore on the south coasts of
Australia; and in Chapter II. reference is made to one that was
stranded on the coast of South Wales.

Miscellaneous Materials in the Beach-drift of the Turks

Islands

Amongst these materials may be specially noticed large spines or
prickles, pumice, floating corals, and electric-light bulbs, the second
and third named deriving special interest from their suitability for
carrying small seeds in their cells or crevices.

The large Prickles of Zanthoxylum. — These large spines or prickles,
which are rather frequent in the drift, are conical in form, and are
apparently detached from the trunks of two species of Zanthoxylum,
a genus including different West Indian trees. The largest prickles
have a diameter at the base of two to two and a half inches, and
belong perhaps to Z. clata-Herculis, the " Prickly Yellow " of the
Jamaican. The smallest kind has a basal diameter of one and a half
inch. These prickles would be able to withstand the transatlantic
passage, and ought to be found amongst the West Indian drift
stranded on European beaches. They are figured by Sloane (Vol. II.,
table 172), though not in connection with drift, under the name of
Euonymus affinis, a tree which, he says, is very common in Jamaica.

Pumice. — The stranded pumice usually consists of small, rounded
pebbles, a quarter to a half inch across, which commonly occur
amongst the smaller drift sorted out by the waves above the line of
the heavier and larger drift. Occasionally one finds large fragments,
as in the case of one washed ashore on the east coast of Grand Turk,
which was seven and a half inches long and weighed one and one-
eighth pound. It was well rounded, and was partially incrusted
with large Serpulid tubes, 5 to C mm. in diameter, and with other
marine organisms. Evidently it had been a year or more afloat, and
might well have been transported from the other side of the Atlantic.

Floating Corals. — Fragments of floating corals stranded on the
beaches of Grand Turk and of the other cays, as well as on the shores
of the neighbouring Caicos Islands, are well known to the residents,
and are termed " floating stones." Occasionally they are picked up

FOREIGN DRIFT OF THE TURKS ISLANDS 165

at sea from boats sailing between the islands. They range from five
or six inches to a couple of feet across, and all apparently belong to
the same kind of Ma^andrine massive coral with large convolutions.
I picked up some small specimens on the beach, and examined others
of large size which a resident had placed in his garden. The largest
measured by me was 17 x 14 x 5 inches in size. It floated when
placed in fresh-water, and probably weighed forty or fifty pounds.
I was informed that larger specimens have been found. Most of the
floating corals examined by me floated in fresh-water as well as in
sea- water ; but in one case the coral floated only in sea- water. Many
years ago floating corals of the same character were examined by me
on Keeling Atoll in the Indian Ocean, and a description of them was
given in a paper contributed to the Scottish Geographical Magazine
for 1889. Reference may be made in this connection to Coral and
Atolls, by Wood-Jones, 1910.

Electric-light Bulbs. — Amongst the " odds and ends " cast up on the
beaches of the Turks Islands are electric-light bulbs. I found three
or four of these stout glass globes, which were all quite intact and
would seemingly float for years. Mr. Savage English alludes, in his
paper on Grand Cayman in the Kew Bulletin (1913), to the occur-
rence of these bulbs amongst the " jetsam " of that island. Doubt-
less they are discarded and thrown over from vessels. They are
quite watertight, and suggest useful floats for current investigation,
as they are very conspicuous on a beach.

CHAPTER VIII

MISCELLANEOUS PLANTS

In this chapter numerous other West Indian Httoral plants, which
are not dealt with in the preceding chapter, are discussed from the
standpoint of dispersal. The object has been to treat in this manner
all the plants mentioned in the table given in Chapter IV., in which
the relation existing among West Indian littoral plants between
their distribution outside the New World and their capacity for
dispersal by currents is illustrated. The small-seeded shore plants,
which raise other considerations, are dealt with in Note 21 of the
Appendix.

Acacia farnesiana, Willd.

This plant came under my notice in different parts of the tropics,
and I made a special study of its station and modes of dispersal in
Hawaii and Jamaica. One may begin the discussion of this widely
spread small tree or shrub with remarking that there is some diverg-
ence of opinion as to its distribution as an indigenous plant. De
CandoUe in his Geographie Botanique (pp. 770, 792) viewed it as of
American origin and as naturalised in Asia and Africa. Bentham
observed that, whilst it was difficult to determine where it was
indigenous, it had the appearance of being so in Western America
from Texas to Northern Chile, in tropical South Africa, and in
Northern Australia, but not in India (Trans. Linn. Soc. XXX., 502).
Baron von Mueller speaks of it as native of Southern Asia and the
warm parts of Australia, and as growing spontaneously in tropical
and subtropical America (Select Extra-Tropical Plants, 1880). The
general opinion, however, leans towards an American origin; but
at present we will accept three facts concerned with its distribution,
as stated by Bentham : (a) that it is widely spread over the tropical
and subtropical regions of the New and the Old World ; (h) that it
has been generally cultivated for the perfume of its flowers; and
(c) that it has been frequently established as an escape from cultiva-
tion. Further consideration of the matter may throw light on the
plant's origin, but since we are dealing with a favourite tropical
cultivated plant which also grows wild in nearly all warm countries
(Hemsley, Bot. Chall. Exped., IV., 148), the initial difficulties are
apparent. It is, however, possible that we may obtain some clue
by regarding the outposts of its distribution, as in the case of its
occurrence on oceanic islands.

Let us commence with the islands of the Pacific. Wherever this

166

MISCELLANEOUS PLANTS

167

plant is found in these archipelagos, whether in Hawaii, Tahiti, the
Marquesas, Raro tonga, Samoa, Tonga, Fiji, etc., the botanist refuses
it a place in the indigenous flora. Its absence from the native floras
of these islands would be readily understood, if it was not at home
on the western borders of the Pacific, that is to say, in the regions
comprising South-eastern Asia, Malaya, and North Australia, whence
the Polynesian plants have been in great part derived. Yet it would
be quite consistent if America was the home of the plant, since
except in the very distant past there have been very few connections
between the American and Polynesian floras. The indications
would seem to be, as inferred by Hillebrand in the case of Hawaii,
that the tree was introduced by the early Europeans into the Pacific
islands.

With the issue thus a little narrowed we will now discuss its dis-
tribution more in detail; but numerous difficult questions at once
present themselves. Why should this particular species of Acacia,
we may ask, wander round the tropics of the globe, when hundreds
of others remain restricted to their homes, principally in Australia
and South America? Hemsley, writing about thirty years ago,
remarked that of the three hundred Australian Acacias, this is the
only non-endemic species (Chall. Bot., IV., 148). Found over most
of the warm regions of the globe, it so often impresses the bota,nist
with the appearance of being indigenous that, as we have seen,
various regions have been assigned as its home. Long ago Willde-
now placed its home in the West Indies and particularly in San
Domingo (quoted by Schmidt in his Cap Verdische Flora). How-
ever, it will be apparent from its behaviour in the Hawaiian Islands,
as described later on, that the plant soon adapts itself to a new
locality and spreads rapidly. The tendency on the part of many
introduced plants to become thoroughly naturalised in a short space
of time is well illustrated in this case, and the modern botanist
with a larger experience of such cases is better able to discriminate
in such matters.

But a further difficulty would present itself in the variety of stations
selected by the plant. Though they would be all consistent with
the behaviour of a xerophilous plant, their variety would tend to
complicate the problem concerned with the home of the species.
It is equally at home in the arid plains of the elevated interior of
Mexico, at the margin of the sea beaches in the West Indian Islands,
and amongst the trees in the loamy soil bordering the mangrove belt
in Jamaica and elsewhere. It may cover the low-lying plains of
the sea border with an impenetrable bush as on the Gulf margins
of Texas, or it may with other trees fringe the dry beds of streams
in the prairies of the same region. Such is its behaviour in the
New World as indicated by Harshberger and others, but the variety
of its stations might be illustrated from other parts of the globe.

Its littoral habit may be first dealt with. Though more typical
of the belt of trees that immediately border the sandy beach, it
accompanies certain of these trees when they grow at the edge of a
coastal or estuarine swamp. In Java, according to Schimper (Ind,
Mai. Strand Flora, pp. 67, 122), it is an essential constituent of the

168 PLANTS, SEEDS, AND CURRENTS

Nipa formation, a brackish-water swamp association predominantly
characterised by Nipa fruticans and stretching inland in the rear
of the coastal mangroves. But it is confined to the drier ground,
and herds with Cerhera odollam and some other characteristic beach
trees of the Barringtonia formation that are equally at home at the
beach margin and at the swamp border. In Jamaica I observed it
growing in the loamy soil behind the mangrove belt in the company
of several other plants, such as Coccoloba uvifera, Conocarpus erectuSy
Guilandina bonducella, Hibiscus tiliaceus, and Thespesia populnea,
that are often associated with it at the margin of the beach. When,
as in Jamaica, it appears on the beach, it will usually be found also
occupying the low district in the rear. But its behaviour in Jamaica
supplies another clue. When one reflects that in the society of the
Mesquite {Prosopis juliflora), Cactacece, Yuccas, etc., it thrives in
the scrub of the extensive Liguanea plains in the interior (Harsh-
berger, p. 678), the suspicion arises that Acacia farnesiana, being
primarily a xerophyte, only presents itself in this island as an intruder
on the beach.

We obtain the same clue when we glance over the other parts of
the West Indies. Millspaugh found it growing inland on St. Thomas,
as well as on the seashore of Porto Rico, and also at Santiago de
Cuba (Plantce Utowance). In the case of Inagua, one of the Bahamas,
Harshberger found it associated with Opuntia and Phyllanthus in
the low thickets of the strand, and in the same company it came
under my notice in the interior of Grand Turk. As in Jamaica,
the chaparral formation, a more or less impenetrable scrub of Acacias
(including A. farnesiana), Prosopis juliflora, Cactacece, Yuccas, etc.,
covers the arid plains of the interior of Hispaniola, an island in
which W^illdenow was inclined to look for the home of the plant we
are now discussing. But it is not in the islands that the chaparral
is best developed, but on the mainland, as in the arid interior of
Mexico, Texas, and the Californian Peninsula as described by Harsh-
berger. Here amidst a motley group of xerophytes, in which
CactacecB, Yuccas and Acacias are conspicuous, the plant we are
now concerned with is at home; and the ever-prevailing Mesquite
(Prosopis juliflora) is its frequent associate. When this scrub
descends from the elevated tablelands of Mexico to the plains that
border the Gulf and extend along the shores of Texas, Acacia fame-
siana accompanies it to the sea-coast. In such situations its claims
to be ranked as a strand plant would be no greater than those of
the numerous other xerophytes of the chaparral scrub that descend
with it to the coast.

If the matter ended here there would be little difficulty in deciding
the point at issue. But not uncommonly in the West Indian region
and in other parts of the world Acacia farnesiana, as already remarked,
discards its associates of the chaparral and takes its place amongst
the characteristic littoral trees. Having explained how the plant
reaches the coast from the inland regions we have now to ascertain
why it remains there. In the answer to this question we may per-
haps find a key to its wide distribution over the globe. It associates
with quite difterent plants in the arid regions of America, Africa,

MISCELLANEOUS PLANTS

169

and Australia. How comes it, we may ask, that the xerophytes
with which it grows in those three continents are confined in the
main to their respective regions whilst this plant occurs in all of
them ? What advantage can this species possess over all the hundreds
of Australian Acacias that have never wandered far from their
home? It is not merely that it is able to adapt itself to a littoral
station; for most xerophilous Acacias could do that; but it is able
to maintain itself there. A shore station gives it some special
advantage over the numerous xerophytic plants of the arid inland
regions. They come and go on the strands of all the continents,
but Acacia farnesiana remains. Why is that ?

It is a matter of dispersal. The number of plants that are dis-
persed by currents, as I have shown in the eighth chapter of my
work on Plant Dispersal^ must be very small indeed, almost infini-
tesimal in relation to the totality of species in the plant world.
From a somewhat extensive acquaintance with the buoyant capacities
of seeds and fruits I feel on safe ground in assuming that nearly all
the species of the chaparral scrub that reach the coast, as on the
Gulf shores of Texas and Mexico, possess no means of effective
dispersal by the currents. They may hold their own in places by
force of numbers, but they cannot extend their range along the
coast to localities where the chaparral is absent. In this respect
Acacia farnesiana possesses a great advantage, as I found in Hawaii,
since its indehiscent pods can float for a month unharmed in sea-
water. Its maintenance at the coast does not depend on recruits
from the inland scrub. It is ensured by the distribution of its
fruits by the currents. Though the seeds themselves sink, they
are buoyed up by the pod.

A reference may here be made to my experiments in Hawaii, as
the details are not given in my previous work, where only the results
are stated. The moist green pods either sink at once in sea-water,
or float heavily and sink in a few days. They are entirely filled
with a kind of pith, the seeds having not yet accomplished their
hardening and shrinking stage. When the pod is ready to fall from
the tree, it is blackened and more or less air-dried, and the seeds
rattle freely inside. Its prolonged buoyancy is due to the cavities
produced by the shrinking of the seeds and the drying up of the
pith. Of five of these dry pods placed in sea-water, one sank in
sixteen days, the next in twenty- three days, and the others in from
thirty-two to thirty-six days, the cause of the sinking arising from
the decomposition of the pith and the gaping of the valves pro-
duced by the penetration of sea-water. This is far, however, from
the type of buoyancy one associates with fitness for trans-oceanic
dispersal by currents ; but it is well adapted for inter-island dispersal
in an archipelago and for extension along a continental sea border.

The behaviour of the plant in the Hawaiian Islands is very sugges-
tive. Regarded by Hillebrand as of early introduction it has spread
over all the islands, and in places forms extensive coastal thickets.
Cattle spread the seeds over an island, and they may often be seen
germinating in their dung; but the currents accomplish the inter-
island dispersal. On some parts of Oahu, where the shrub grows

170 PLANTS, SEEDS, AND CURRENTS

abundantly near the sea, the pods are washed up in great quantities-
on the beaches, and the freed seeds are to be seen germinating in
numbers, the seedhngs striking into the sand. It occurs as a char-
acteristic beach shrub around the coasts of Hawaii, Oahu, etc., and
has been spread by the cattle far inland. Hibiscus tiliaceus is its
frequent associate. Spreading up some of the valleys of Oahu
Acacia farnesiana forms extensive thickets impenetrable for cattle,
typical chaparral scrub but of recent growth. This matter is dealt
with at length in my work on Plant Dispersal,

The occurrence of Acacia farnesiana in oceanic islands needs a
little further consideration. One may suspect that this shrub or
small tree was introduced by man into islands when they lie far
from the continents, since its capacity for dispersal by the currents
would probably be limited to traverses of tracts of sea not more
than 400 or 500 miles across. Cambage ascertained that the seeds
preserved their germinative power after an immersion of five or
six months in sea-water (Journ. Proc. Roy. Soc. N. S. Wales, XLIX.,
1915, p. 94). But since the seeds had no buoyancy, he appealed
to the pods. On finding, however, that a single pod sank in a few
days, he inferred that the seeds might be carried for very long
distances in drift-w^ood or pumice. This means of dispersal, how-
ever, would be at the disposal of all the species of Acacia that happen
to grow near the beach, and would not of itself be sufficient to explain
the exceptional range of the species in question. He does not
introduce the agency of man, an agency that would at once give
the plant a great advantage over other Acacias not so favoured.

One can scarcely doubt that this plant was introduced by Euro-
peans at an early date into the Cape Verde Islands and Madeira,
either from the West Coast of Africa or from Southern Europe where
it has long been cultivated. It was collected by George Forster
on St. Jago in 1778 (1779?), and was regarded by Schmidt in the
middle of the last century as truly indigenous in the group {Flora
der Cap Verdischen Inseln, 1852, pp. 38, 342). Welwitsch, who was
in the islands about that time, refers to it as subspontaneous
(Catalogus Herbarii Gorgonii, by Prof. Coutinho, 1914-15). It also
seems to have been introduced into Fernando Noronha, though it
is now behaving as an indigenous plant. The thorny Acacia bushes
that were described by Moseley as abundant on the shore during
the visit of the Challenger about 1874 (Chall. Bot., III., 11) were
probably of this species. Ridley, who found Acacia farnesiana
growing in thickets in the interior of Fernando Noronha in 1887,
regarded it as having been introduced (Journ. Linn. Soc. Bot., vol.
27). In 1836 an Acacia was collected by Darmn on Keeling Atoll,
which was referred to this species {Chall. Bot., IV., 113). During my
sojourn on the atoll in 1888 I did not observe that it formed a feature
of the indigenous flora. It was probably one of the numerous plants
introduced in the early days of the occupation of the islands.

Of the several authorities on the floras of the oceanic islands of
the tropical Pacific, not one includes this species amongst the indi-
genous plants, that is to say, the plants found in the islands at the
time of their discovery. Mann and Hillebrand for Hawaii, Seemann

MISCELLANEOUS PLANTS

171

and Home for Fiji, Hemsley and Burkill for Tonga, Reinecke for
Samoa, Cheeseman for Rarotonga, Jouan and Drake del Castillo
for the Tahitian Group, the Marquesas, and the Paumotus, all in one
way or another disclaim the plant. Many of them do not mention
it. Seemann, however, remarks that in his time (1860) it was
strictly confined to the gardens of white residents in Fiji. Hille-
brand, as we have seen, regards it as a plant of early introduction
in the Hawaiian Islands. Since he does not include it in his list of
plants introduced by the natives in prehistoric times (p. xvi.), we
may suppose that he places it amongst " several species of Acacia
(that) might well claim a place " amongst plants introduced since
the time of Captain Cook. If this was the case. Acacia farnesiana
must have quickly become established, since in Hillebrand's time
(1851-71) it was " spread over all the islands." Cheeseman, also,
made a list of plants probably introduced into Rarotonga by the
natives prior to the arrival of the white man ; but this plant does
not figure in the list. From these data, I think that it is fair to
assume that botanists do not credit Acacia farnesiana with a pre-
European existence in the Pacific islands. (With the exception of
the writings of Jouan and Mann, which are quoted by Hemsley
(Chall. Bat., IV., 148), all the works of the other authorities named
are given at the beginning of my work on Plant Dispersal.)

It would be possible to extend this discussion very considerably;
but I have gone far enough to show the probability of this plant being
indigenous in the New World. Bentham would place South Africa
and Australia in the same category. However, Cambage included
this plant in his recent studies of the history of the Australian
Acacias, as indicated by their seedlings, and he looks rather to
America for the home of the plant (Ibid., p. 97). This will remind
us that there is another way of approaching the problem. Not the
least valuable outcome of the studies of Andrews of the adaptation i
of plant-forms to the special conditions of Australia will be the
sidelight often thrown on problems of this kind. The following
considerations respecting this plant have suggested themselves after
a perusal of his recent paper on the Leguminosce (Journ. Proc. Roy.
Soc. N. S. Wales, Vol. XL VIII., 1914). From his discussion of the
Australian Acacias I would infer that although Acacia farnesiana
is at home in Northern Australia, it does not display the special
Australian impress which attains its maximum expression in the
development of the phyllode, a character of Acacias amongst which
the plant we are discussing finds no place. The section, Gummiferce,
to which it belongs, seems to have obtained no secure footing in
Australia (p. 395) ; and the other types of the series, of which it forms
one, are endemic in America, in Africa, or in Asia (p. 392). We
could, therefore, scarcely regard Acacia farnesiana as a gift of
Australia to the littoral flora of the tropical zone. We have pointed
out the probability that either directly or indirectly Australia origin-
ally supplied species of Sccevola, Dodoncea, and Cassytha, that frequent
the shores of the Old and the New World in warm latitudes ; but the
same, it would seem, cannot be said for Acacia.

I may conclude this discussion with the remark that Acacia

172 PLANTS, SEEDS, AND CURRENTS

Jarnesiana has here been taken as a sample of a small group of
cosmopolitan tropical and subtropical plants, including such as
Hibiscus tiliaceus and Thespesia populnea, which, though often
differing greatly in other particulars, are linked together by the
difficulties which their distribution presents. Equally at home at
the coast and inland, and all capable, though to a varying degree,
of dispersal by currents, there is always more than a suspicion that
man has assisted for ages either directly or indirectly in their dis-
tribution. Over all of them hangs a doubt as to their birthplace,
since they behave as indigenous plants over most of the warm regions
of the globe. In their present range they seem to be quite inde-
pendent of the development centre of the genus. If the botanist
places the plant concerned in one hemisphere, the errant species
presents itself as to all appearance an indigenous plant in the other.
The student of distribution quarrels with all of them in one region
or another, since they figure too frequently as disturbing factors in
his speculations on the history of a flora.

Both Hibiscus tiliaceus and Thespesia populnea are treated in a
later page, but with less detail as the writer hopes to take up the
further study of the story of their travels around the globe. Their
history is bound up with that of aboriginal peoples, and they raise
somewhat different issues than does the species of Acacia with which
we have been concerned. The names of Hibiscus tiliaceus and
Thespesia populnea are part and parcel of the native languages
around the tropics, and we can almost detect a linguistic affinity
between those of the New and the Old World. On the other hand,
Acacia farnesiana is a nameless plant, as the philologist would
express it, around the tropics of the globe. It has names, it is true,
but not names that belong to the language of the aborigines in whose
country it may now grow. It has been a great traveller, but its
story is bound up rather with the continents than with islands,
rather with early civilisations than with states of barbarism. From
the circumstance that it has been identified with the " Small Acacia "
of Dioscorides, and has been even supposed by some to have been
represented by its flowers in Egyptian tombs (Von Mueller, Extr.
Trap. Plants ; De Candolle, Geogr. Bat.), we may have to face quite
other issues.

Ambrosia crithmifolia, DC. (A. hispida, P.)

This composite beach plant ranges all over the West Indies,
including the Bahamas and the Florida keys and the continental
shores of the Caribbean Sea. Growing prostrate on the sand with
its flowering spikes rising six to twelve inches in the air, it gives a
peculiar aspect to the surface, reminding one a little, as regards the
foliage effects, of an English sand-dune covered with Matricarias.
When it carpets extensive tracts of sandy plains bordering the sea,
the aromatic fragrance of the plant is often borne far to seaward
by the wind blowing off the shore.

Detached from the parent plants the small dry fruits, enclosed in
the persistent involucre, occur in numbers in the sand of beaches.

MISCELLANEOUS PLANTS 173

* from which they could readily be swept off by the waves and carried

away in the currents. However, my experiments in the Turks
Islands indicate that they possess limited floating powers. Picked
up by the waves, and washed off the beach, they would sink in
from two to four days. Prolonged drying for a year and more
adds but little to their buoyancy, half of them sinking in two days,
whilst the few remaining afloat after a week are only floated up by
adherent air-bubbles. The achene removed from the involucre has
initial buoyancy, but sinks within four days. Though unsuited for
direct distribution by the currents over broad tracts of sea, these
small fruits might be carried great distances in the crevices of a
drifting log. They would readily be washed with the sand into the
crevices of timber temporarily stranded on a coast.

The achene shut up in the dry involucre would not be likely to
tempt sea-birds, and the fruits do not attach themselves to plumage.
The achene is 2-5 to 3 mm. in length. The length of the fruit with
the persistent involucre is 4 mm.

The genus holds fifteen known species, of which all but one are
confined to the New World. The exception is a widely spread
Mediterranean shore plant {Ambrosia maritima, L.) which extends
to the coast of Senegal. Certain of the species range far and wide as
waste plants and weeds in the American continent and in the West
Indies. Some North American species frequent estuarine marshes,
whilst others prefer the sand-prairies of the interior and the borders
of salt swamps in inland regions (Harshberger) .

I found Ambrosia crithmifolia thriving on six of the ten cays of the
Turks Islands, and reference to it in this connection will be found in
the chapter on the flora of these islands. Mr. Lansing's observations
on the Florida sand-keys, where he found it growing on five of the
nineteen keys examined, indicate that it is one of the earlier plants
to occupy land newly gained by accretion from the waves. Yet the
fact that it has not been observed in Bermuda, which has received so
many West Indian strand plants, militates against the efficacy of the
currents in transporting it across broad tracts of ocean.

Anacardium occidentale, L. (Cashew-nut)

The nuts of this West Indian tree, which is only indigenous in the
New World, do not form a feature in the beach-drift of these regions.
On one occasion I found a solitary decaying nut on a Jamaican
beach; but that alone could not entitle it to be regarded as a drift
fruit. Yet it is interesting to note that Gunnerus, who lived in the
middle of the eighteenth century, found this fruit on the Norwegian
coast; but Sernander in his book on the Dispersal-Biology of the
Scandinavian flora (p. 117) tells us that it has not been found since.
Hemsley, who quotes Linnaeus on this point, says that the seed was
in a living condition, and he places the fruit among those certainly
or probably distributed by currents (ChallBoL, I., 43; IV., 278, 305).

This Norwegian drift fruit has puzzled me much, since Linnaeus
gives no other particulars concerning it. The large fleshy peduncle
could not possibly be here concerned, unless it was thrown over

174 PLANTS, SEEDS, AND CURRENTS

from some vessel near the Norwegian coast; whilst it is scarcely
likely that the heavy nut when fresh could have much buoyancy.
This is indicated in one of my experiments. I placed in sea-water
some sound nuts which had been gathered rather over a year. After
a few days the pericarp began to soften, and in ten days all the nuts
were at the bottom of the vessel, a week being the average flotation
period. Empty nuts are much lighter and might float longer.

Anona palustris, L.

The genus Anona, or, as it is now usually written, Annona, has
been fortunate in its latest monographer, Dr. W. E. Safford, who
has recently published in volume 18 of the Contributions from the
United States National Herbarium for 1914 a classification of the
genus. Here we are mainly concerned with the littoral and estuarine
tree above named ; but from the distribution standpoint it cannot be
treated without some reference to a few of the general features of
the genus to which it belongs.

" The genus Annona " (writes Dr. Safford, p. 4) is confined
almost exclusively to tropical and subtropical America. At an early
date, however, certain species were introduced into the warmer
regions of the Old World for the sake of their edible fruits, and
were described as distinct. In addition to these there are a few
species endemic in tropical Africa." The author gives no numerical
account of the distribution of the genus in his paper. Failing this,
a general statement of the results for about 120 species named in
the Index Kewensis may be given. Here about 100 species are
exclusively American. Of the balance most are tropical African,
and the rest occur in Madagascar, the Mascarene Islands, Ceylon,
China, and Malaya, with one species, A. palustris, both American and
African, the only species common to the Old and the New Worlds.
Some emendation is, however, here required respecting the few
Asiatic species named in the Index Kewensis, since Dr. Safford
informs me that " there is no endemic Anona in Asia. . . ." The
manner in which the edible species, the Sops, the Custard Apples,
the Cherimoya, etc., have been spread over the world by man, not
only in recent times but by the early European navigators, suggest
that human agency may have been effective in this direction, even
in prehistoric times. (Dr. Safford tells me, in a letter since received,
that " certain economic species were introduced into India at a
very early date.")

It is a significant fact that the only species which links together
the Old and the New Worlds, the cultivated species being excluded,
is one of the plants of the mangrove association, namely, Anona
palustris, a tree that finds its home in estuaries and in coastal swamps.
As far as I can ascertain there is no other species that could be
regarded as a littoral plant. There are one or two species like
A. paludosa, Aubl., that grow in marshy situations at the coast,
but they also occur inland. Nor are there any plants that are
exclusively confined to the vegetation bordering the sandy beaches.
Where such plants grow in sandy plains at the coast they belong

MISCELLANEOUS PLANTS 175

i

to an association of inland xerophilous plants that in places descend
to the sea-border. We would therefore expect that Anona would
illustrate the principle exemplified by many tropical genera, such as
Barringtonia, Calophyllum, Clerodendron^ Cordia, Guettarday Morinda,
Sccevola, Terminalia, etc., that where a genus comprises both coast
and inland species only the coast species possess seeds or seed-vessels
adapted for effective dispersal by currents. This principle, which
is laid down in the second chapter of my book on Plant Dispersal,
might be considerably extended now, and the indications especially
concerning Anona will be stated below. But a few remarks on the
station characteristics of the genus are first required, as well as some
preliminary observations on its means of dispersal.

The capacity of the genus for adapting itself to very different
stations is remarkable. Some species are at home in the humid
conditions of the dense mountain forests ; others thrive in the drier
conditions of the open- wooded districts ; others grow in the savannas
and grassy plains; others are found in the sandy plains near the
coast, and others in the desert rocky regions in the company of
xerophjrtic Cactacece, Agaves, and Acacias. A few live in inland
and coastal marshy districts, and one is the associate of the man-
groves at the borders of estuaries and in the swamps at the sea-coast.
Probably the xerophytic habit is most typical of the Anonas of our
own day; but as indicative of a tendency to resume, what I would
regard as the primeval habit and station of the genus, these plants
even in their driest stations tend to gather along the streams, and
where the conditions are too arid for permanent streams they may
be found in the dry rocky beds of the channels that serve as water-
courses only during the rains. I would consider that the genus was
primarily a denizen of wet forests in warm latitudes, and that it has
often become adapted to drier climates during the differentiation
of climate in later ages.

The modes of dispersal of these plants may be now discussed.
The question is at once raised when we contrast the distribution of
Anona palustris, the only species common to the eastern and western
hemispheres, with other species that are restricted to one or other
of the two hemispheres. Dr. Safford in a letter to Prof. Harshberger,
which is given below, strikes a true note regarding this tree when
he writes : "If it were birds that distributed the seeds, why would
not the more attractive species be just as widely dispersed? The
^ seeds may possibly be borne by currents." The answer to this
query is indicated below, and it would seem, as far as these data
can guide us, that although birds and other creatures may be effec-
tive agents in local dispersal, the currents come into play when
broad tracts of ocean have to be crossed. That Anona seeds are
swallowed by fruit-eating birds of the pigeon family is stated by
Gosse in his Birds of Jamaica (pp. 308, 315; 1847). Both the Pea
Dove (Zenaida amabilis) and the White-belly Pigeon (Peristera
jamaicensis) feed upon them. Parrots no doubt feed on the fruits,
though I don't know whether they would swallow the seeds. One
of the Mexican species is named " the little custard apple of the
parrots " (Safford, p. 55). Pigs, iguanas and alligators are also

176 PLANTS, SEEDS, AND CURRENTS

stated to be partial to these fruits, one species {Anoyja palustris)
being kno\\Ti in Jamaica as the AlUgator Apple.

Since none of the Anona seeds examined by me are impervious to
water, it is unlikely that they would be able to withstand the injurious
effect of the digestive fluids of birds for more than a few hours. It
is quite possible that a pigeon might transport them unharmed
across a strait two hundred miles in width, but that would be the
limit. We must look for other agencies, therefore, to explain the
case or cases where broad tracts of ocean have presumably been
traversed by the species ; and when the fruit of such a plant is inedible
and the species is not likely to have been spread by man we must
appeal to the currents. If in addition to these features we find that
the plant concerned is a denizen of coast swamps and is associated
with mangroves that are well known to be distributed by currents,
then the presumption in favour of the current hypothesis becomes
very strong, and we would expect to find that the seeds of all other
species, where the question of oversea transport is scarcely raised,
would be ill-fitted for crossing an ocean in a current. It is not a
matter of fruit-buoyancy, since the floating fruit would soon break
dowTi, as is illustrated in the case of that of Anona palustris in a
later page, and the fate of the species would be ultimately determined
by the behaviour of the liberated seeds.

What, therefore, we may ask, is the behaviour of seeds of Anona,
when their buoyancy is tested? The answer to this question is
indicated on p. 177; and though the seeds of only five species have
been experimented upon, the data go to show that Anona comes
into line with many other tropical genera where only the littoral
species are adapted for dispersal by currents.

It will be learned from the results tabulated on p. 177 that it is only
the littoral species with inedible fruits and seeds capable of floating
a long time in sea- water that occurs outside the New World, namely,
on the coast of tropical West Africa. This species, Anona palustris
(syn. A. glabra), deserves a special discussion.

We may best begin with Dr. Safford's letter to Prof. Harshberger,
which is given on p. 155 of the latter s paper on the vegetation of
South Florida (Trans. Wagner Free Institute of Science, Philadelphia,
October 1914) : " A letter of query directed to Dr. W. E. Sa^ford,
who has monographed the genus Annona, as to the means of dis-
tribution of the custard-apple, elicited the following information under
date of August 20, 1912 ' —

" Dear Sir,

" I have the honour to acknowledge the receipt of your
recent letter in which you ask suggestions as to how the swamp-
apple, Annona glabra, is dispersed. This is a question which has
perplexed me. The associations of this plant are with species of
so-called mangroves of wide distribution. This species itself occurs
on both sides of tropical America, the Galapagos Islands, and the
West Coast of Africa. It would be interesting to find out whether
detached branches take root readily in the mud. The wood is so
light, it is called corkwood, and the roots are used for corks and

MISCELLANEOUS PLANTS

177

Remarks

The spongy tissue
is the only part
of the fresh seed
that possesses
independent
buoyancy

Ditto

Ditto

Ditto
Ditto

Amount of Spongy
Buoyant Tissue lining
the Seed-sheU

Scanty. Mostly
at the hilar end

Scanty

More scanty than
with Anona
muricata

Scanty

Well developed

Buoyancy of Seeds

Moist, fresh seeds
sink. Seeds dried

for six months
float from two to
four days

Seeds dried for six ;
months sink in a
day or two

Seeds dried for six
months sink in a
day or two

Seeds dried for six \
months sink in
a day

Fresh seeds float
for weeks and
months

Fruit Edible
or Inedible
for Man i

Edible

Edible

Edible

Edible

Inedible

Station, etc.

Coast

Wild. Not
cultivated.

Muddy
shores of
estuaries and
borders of
mangrove
swamps

Inland

Wild in
woods. Also
cultivated

Wild. Also
cultivated

Wild in for-
ests, thickets,

and dry
plains. Also
cultivated

Wild. Also
cultivated

Distribution

Tropical
America

Tropical
America

Tropical
America

Tropical
America

Pacific and
Atlantic

coasts of
tropical

America and

coasts of
tropical

West Africa

Species

Anona muricata,
L. (Sour Sop)

Anona reticulata,
L. (Custard Apple)

Anona squamosa,
L. (Sweet Sop)

Anona cherimolia,
Lam. (Cherimoya)

Anona palustris, L.
syn. A. glabra, L.
(Alligator Apple,

Swamp „

Monkey

Pond „

Custard

of South Florida)

r3 .

£S

« o

N

178 PLANTS, SEEDS, AND CURRENTS

floats for nets. An experiment might be made by breaking off
limbs or roots, and after soaking them for a time in salt water plant
them in mud. I cannot find that their fruits are any more buoyant
than other Annonas. If it were birds that distributed the seeds,
why would not the more attractive species be just as widely dis-
persed? The seeds may possibly be borne by currents. They say
that the fruit is eaten by aquatic lizards, or iguanas of the Bahamas.
I wonder if they are carried from island to island. ..." (It may
be noted here that according to Fawcett and Rendle in their work
on the Jamaican flora the light wood is used for corks, floats, etc.,
nothing being said of the roots. — H. B. G.)

The ground covered by this extremely suggestive letter will be
traversed in the following discussion respecting Anona palustris.

The distribution of this plant in the New World extends on the
Atlantic side from South Florida and the Bahamas over the Greater
and Lesser Antilles to the South American mainland. On the
Pacific side it is at home on the coasts of Central America, the Gala-
pagos Islands, and on the coast of Ecuador, its southerly extension
beyond the Peruvian borders being prevented by the aridity of the
climatic conditions, which bring the mangroves and their associated
plants to a halt in this region. On the West Coast of Africa it grows
on the coasts and estuaries of Senegambia and in the Niger region.

Its station is at the borders of the mangroves, and it is at home
on the muddy banks of estuaries. I found it to be one of the most
frequent trees on the banks of the Guayas estuary in Ecuador, where
they were overflowed at high water. Here it was associated with
Rhizophora mangle, Hibiscus tiliaceus, and other trees. It is a
constituent of the mangrove formation on the coasts of the Virgin
Islands in the West Indies and of the island of New Providence in the
Bahamas (Harshberger's Phytogr. Surv. N. Amer., pp. 687, 690-1).
It does not appear to be frequent now in Jamaica. I did not come
upon it myself in the Black River district, though in the recent
volume on the Flora of Jamaica by Fawcett and Rendle, where only
two localities are given, this is one of them. A fruit was brought
to me from the north side of the island.

But one of the most interesting localities where Anona palustris
occurs is in South Florida, where, as we are told by Prof. Harshberger,
from whose memoir on the region the following details are taken,
this tree offers one of the most remarkable formations. In these
low-lying levels it occurs thirty to forty miles from the sea in an
area which has been for ages undergoing a transition from its con-
dition of submergence beneath the Gulf Stream in later Tertiary
times to one of marsh and swamp, and finally of dry land. The
greatest development in this region is a forest of "an almost pure
growth " of this tree, which, varied by an occasional cypress {Taxo-
dium distichum), forms a band usually two to three miles in breadth
for a distance of about thirty miles along the south and south-east
shores of Lake Okeechobee, passing on its southern side into the
marsh formation of the Everglades. Two or three of the islands
in this lake support a dense growth of this tree. In some places

MISCELLANEOUS PLANTS

179

the Anona trees, when within a distance of five or six miles from the
coast, blend with an outer zone of cypress swamp. In other places
where they approach the coast they are associated with Rhizophora
mangle. In others, again, they largely form hammocks, or groups
of trees, that rise up like islands in the midst of the marsh vegeta-
tion of the Everglades. One of the characteristic developments of
the tree occurs in the Banana Holes, which are shallow depressions
or sinks, in which water often collects, where flourish a variety of
other plants, Chrysohalanus icaco, Cladium, Phragmites, Sabal, Sagit-
taria, Salix, Typha, etc.

From what has been said it would thus appear that in South
Florida this tree has many associates of a very different kind, and
we may regard its behaviour there as the story of a tree of the man-
• grove formation that has been endeavouring for ages to gain for itself
an inland station.

As regards the modes of dispersal of Anona palustris it is likely,
as suggested by Prof. Harshberger (p. 116), that the seeds are locally
distributed by frugivorous birds. He also adopts the suggestion of
Dr. Safford that it is distributed by its light, corky wood, fragments
of the tree being carried by water. Observation and experiment
will show whether this last mode of dispersal is effectual. However,
a very effective method of dispersal came under my notice in the
Guayas estuary in Ecuador, a method described ten years ago in
my book on Plant Dispersal (pp. 488-9). Very frequent in the
floating drift of the river off Guayaquil were the seeds of this tree,
often in a germinating condition. The seeds were liberated by the
decay of the floating fruit, which was also common in the river-drift.
They occurred commonly amongst the materials afloat in the Gulf
of Guayaquil, ten to twenty miles off the mouth of the estuary,
and were washed up on the beaches thirty miles to the south. Ex-
periments showed that the seeds will float in sea-water until they
rot and decay — one experiment covering eleven weeks, none of the
seeds sinking, though several had become putrid. Seeds from
Ecuadorian and Jamaican trees behaved in the same way.

The tendency of the seeds to germinate whilst afloat in rivers
raises an objection against their fitness for dispersal by currents,
since sea-water would probably kill the germinating seed. Here a
good deal depends on whether the small embryo has begun its growth
within the albumen before the seed reaches the sea. In the resting
condition the embryo is only about one-sixth of the length of the
nucleus of the albumen, which is about 11 mm. long, and the cotyledons
are minute. Considerable growth of the cotyledons takes place
within the seed at the expense of the albumen before the tip of the
radicle protrudes; and ultimately the cotyledons occupy almost
the length and breadth of the seed nucleus. It is therefore apparent
that a great deal depends on whether the embryo has passed beyond
the resting-stage before the seed reaches the open sea. When the
embryo is about one-third of the length of the nucleus, the tip of
the radicle, which abuts against the pervious hilar end of the seed,
has for its sole protection a thin membranous layer of albumen.
In the resting seed, the embryo is better protected by the albumen

180 PLANTS, SEEDS, AND CURRENTS

for an oversea traverse; yet even here the impervious outer skin
is deficient at the hilar or radicular end of the seed.

A curious feature in the buoyant behaviour of the seeds of Anona
palustris is that they are, like other seeds of the genus, permeable to
water and air. When dry they behave hygroscopically and vary in
weight 2 or 3 per cent, according to the humidity of the surrounding
air. Fresh and moist from the fruit they owe their floating powers
entirely to the layer of cellular tissue lining the seed-shell, no other
part of the fresh seed possessing independent buoyancy. An exami-
nation of seeds that had been afloat some weeks showed that until
they became water-logged or saturated with water, there was no
soaking of water into the seed substance, but rather a vital process
of absorption of water, such as occurs in seeds imbedded in the
ripe fruit. Seeds that had been afloat for three weeks, after being
placed in a dry state in the water, were found to have taken up w^ater
only to the extent that it occurs in seeds in the fruit, the interior
of the seed being fairly dry. Sufficient moisture had been absorbed
to restore the normal moist condition of the seed as it lies in the
fruit, and the embryo had resumed its original full outlines. There
were no signs of saturation.

A point of importance is concerned with the degree of salinity
that the floating seeds of Anona palustris will withstand without
injur}^ to their powers of germination. In the river Guayas the
germinating seeds were floating unharmed in brackish water that
at high water had a density of about 1-003. From the association
of this tree with the mangroves, the germinating fruits and seeds of
which are not affected by sea-water, it is probable that its seeds
can germinate in brackish water, though it is not likely that they
would do so in pure sea-water. Nor do 1 think that the Anona
trees would thrive in pure sea-water. The muddy banks of the Guayas
estuary, on which they flourish, are overflowed by brackish w^ater
at high tide. But more observations on this point are needed.
These trees grow in brackish water in the Bahamas (Harshberger,
p. 691); and it is apparent that on the South Florida coasts, where
they are associated in the swamps with the mangroves, the water
must at least be brackish. But they are only halophilous by force
of circumstances. Their great development in the inland regions
of South Florida has taken place around fresh-water lakes, and
such conditions are evidently the most congenial for their growth.

A singular point arises as to the practical bearing of these observa-
tions and experiments on the occurrence of Anona palustris on both
sides of the tropical Atlantic. It is just possible that the seeds
could safely traverse the Atlantic in the Main Equatorial Current
from the Gulf of Guinea to Brazil, a passage which would require
a period of two or three months, this being the only available trans-
atlantic route for seeds of their floating capacity. Yet Anona is
now almost exclusively an American genus, and if there has been
an interchange America has the first claim to be considered the
giver. But this would compel us to suppose either that the seeds
had been able to withstand the six to eight months' passage involved
in the Counter Equatorial Current, or that they could accomplish

MISCELLANEOUS PLANTS

181

unharmed the long trans-oceanic passage of about two years from
the West Indian region in the Gulf Stream drift to the West Coast of
Africa. We are here presented, therefore, with a dilemma such as
was offered by Chrysobalanus icaco, one that could be evaded only
by postulating a common centre of dispersion in high northern
latitudes in a warmer geological age. This postulate seems the
more probable, since, as Dr. Safford informs me, Anona senegalensis,
a typical shrub or tree, that extends from the East to the West Coast
of Africa, is apparently most closely related to certain species
growing on the plains of Southern Brazil and Paraguay " (letter
cited).

A word may here be said on the synonymy of this species. Dr.
Safford conclusively shows (p. 14) that the two plants to which
Linnjeus originally applied the specific names of glabra and palustris
belong to one species. But it is possible that under the same specific
type may be also included Anona klainii, Pierre, of the West Coast
of Africa, w^hich is at all events " very closely allied to A. palustris,
if not identical with it." Dr. Safford, whose work has here been
quoted (pp. 5, 15) tells me that the seeds of the two cannot be dis-
tinguished. I would point out that whilst on p. 15 this author
speaks of these two species as on the West Coast of Africa, he alludes
to them on p. 5 as on the eastern coast of the continent. That the
West Coast is the true habitat is, however, indicated in his letter to
me. Prof. Urban, as he shows, formed the same opinion of the
close affinity of the two forms.

In conclusion, reference may be made to a curious abnormality
frequent in the seeds of another species of Anona {A. muricata).
Here the cotyledons are separated by a thin sheet or film of the
endosperm, about half a millimetre in thickness, which occupies
the length and breadth of the seed-kernel with the exception of a
deep notch in its base for the hypocotyl. It is best examined after
the embryo has begun to grow, and is about half the length of the
seed.

ASTROCARYUM

Empty fruits of different species of this genus of palms were
identified at Kew amongst my beach-drift collections from the Pacific
and Atlantic sides of the Panama Isthmus. They were also included
among the Morris collection of Jamaican beach-drift (Chall. Bot.,
IV., 304). I found them occasionally on the Trinidad coasts ; but
they did not come under my notice on the beaches of the Turks
Islands. However, since I came upon a typical specimen on the
coast of Pico in the Azores, it would seem likely that they would
reach the shores of Europe. The drift fruits are always empty.
They are rather like miniature coco-nuts, and are usually about
IJ inch or 31 mm. in length.

AVICENNIA NITIDA, Jacq.

This mangrove is found all over the West Indies and along the
continental coasts and estuaries of the warm regions of the New

182 PLANTS, SEEDS, AND CURRENTS

World, as well as on those of the West Coast of Africa. There will
be no necessity to discuss here the station of this tree in the outer
zone of the mangrove swamp, and I will limit my remarks here
to the part played by the young seedlings, on being freed from the
fruit coverings, in distributing the plant.

In my book on Plant Dispersal (p. 489) mention is made of the
abundance of these seedlings in the lower course of the Guayaquil
River in Ecuador, and of their being carried out to sea and stranded
in numbers on the coasts near the estuary. Germination com-
mences on the tree, and it is in this condition that the fruit
usually falls into the water of an estuary. There it floats, and
the seedling soon frees itself from its envelopes and floats away.
The germinating fruits were to be observed in numbers thrown up
on the beaches of Jamaica, Trinidad, Tobago, etc. It is important
to note in this connection that sea-water is not injurious either to
the germinating fruit or to the freed seedling, and that the seedling
could be transported for considerable distances unharmed in the
sea. It has been shown by Dr. Millspaugh that with the two ether
mangroves, Rhizophora mangle and Laguncularia racemosa, Avicennia
nitida is one of the earliest plants to establish itself on the Florida
sand-keys. All three mangroves have made their home in the
Bermudas.

The germinating fruit and the freed seedling might retain their
vitality a considerable time after being stranded on a beach. In
Jamaica I took five fruits on the point of falling from the tree.
They were on the eve of rupturing, and I inferred from the con-
dition of other fruits in the same stage that each of them contained
a dark-green, well-developed seedling. They were allowed to dry
in a room, with occasional exposure in the sun, for twenty-five days,
during which period three of them opened. They were then placed
in fresh- water, and within a week two of them were growing healthily,
notwithstanding that they had lost just 50 per cent, of their weight
in the drying process.

Avicennia seedlings offer the only means of the dispersal of the
plant by currents, and although considerable tracts of ocean might
be safely crossed in this manner, it is not at all probable that they
could accomplish unharmed the long transatlantic passage in Gulf
Stream drift from the New to the Old World. On the other hand,,
they seem sufficiently hardy to survive the much shorter passage
of from two and a half to three months in the Main Equatorial Current
from the west coast of Africa to Brazil. Avicennia is regarded as
an Asiatic genus, and according to this view the borrowing of its
species from the Old W^orld by way of the West Coast of Africa would
be quite consistent. As regards the time occupied in the traverse
in the Main Equatorial Current, it would be similar to that taken
up in the passage from the Florida region to the Bermudas, namely,,
two to three months, a passage that Avicennia seedlings must have
once safely performed previous to the establishment of this mangrove
on those islands. (See Note 14 of the Appendix respecting Bermuda
bottle-drift.)

MISCELLANEOUS PLANTS

18S

BORRICHIA ARBORESCENS, DC.

This is a maritime Composite shrub, usually two to three feet high,
which is very typical of the warm regions of the New World. It
belongs to a genus exclusively American and comprising only two
allied species, of which the present one ranges over the West Indies
and tropical continental America, whilst the second (B. frutescenSr
DC.) grows in the Southern United States and in Mexico, both species
being indigenous seaside plants in Bermuda (Chall. Bot., II., 45).
Although we are only concerned here with the wide-ranging species,
it is highly probable that the results of my observations on the
dispersal capacities will apply to both.

This shrub commonly frequents rocky stations at the coast, but
it also grows on sandy beaches and on the dunes in their rear. It
often presents in the same locality two forms, one with glabrous
foliage and the other with leaves covered by a silvery down; but
both kinds of leaves may occur on the same individual. The writer
specially studied the plant from the dispersal standpoint in Jamaica
and in the Turks Islands. Its most critical habitat is in the Florida
sand-keys, where we see in operation the earliest stage of plant-
stocking in these regions, so well observed by Mr. Lansing andi
described by Dr. Millspaugh {Field Columbian Museum, publ. 118,.
Bot. Ser., 1907). After the mangroves it takes a place amongst the
first seven or eight strand plants that occupy the newly formed
islets in these seas.

The next critical habitat is Bermuda, since the question of the
fitness of the fruits for transport by currents across broad tracts
of sea is at once raised. The achenes, including the short crown,
are from 4 to 5 mm. long; but there are no hairs nor any means of
attaching the fruits to plumage. Looking to the currents for a
possible explanation of the wide range of the plant, I tested the
buoyancy of the fruits both in Jamaica and in the Turks Islands.
In my Jamaica experiments they sank after soaking in sea-water
for a day or two. In those made in the Turks Islands on the plants
of that group, the fruits floated on the average six or seven days,
the limit being ten days ; but in a later experiment in England on
fruits of the same set, which had been kept for fifteen months, they
floated on the average nine or ten days, the limit being seventeen
days. In such experiments it is requisite to select the achenes
very carefully, since from insects and other causes it is often not
easy to find achenes with sound seeds.

In the light of these results it is evident that the original fruits
could not have reached Bermuda by their own floating powers,
a passage, as shown in Note 14 of the Appendix, that would usually
occupy nearly three months. Nor can we appeal to the agency of
sea-birds, since the dry fruits would not be likely to be swallowed by
them, whilst, as already remarked, they do not adhere to plumage.
We are thus driven to conjectures. It may be suggested that the
achenes were accidentally introduced into the Bermudas with the
salt brought from the Turks Islands in the seventeenth century.
In those times there was a regular trade between the two groups in

184 PLANTS, SEEDS, AND CURRENTS

this article, as shown by the report of Mr. F. H. Watkins on the salt
industry of the Turks Islands (Colonial Reports, MiscelL, No. 56, 1908).
As the plant thrives around the creeks and ponds that supply the
salt-pans on Grand Turk, it is not improbable that the original
achenes might have been contained in salt shipped to Bermuda.
But against this view there is the fact that the plant was cultivated
before 1699 in England at Hampton Court from Bermudian sources
(Chall. Bot., II., 45). On the whole it would seem most likely that
the original fruits were transported to the Bermudas buoyed up
in the miscellaneous Gulf Stream drift that is stranded there in
quantities.

Cakile

My remarks on this genus will be mainly directed to the question
of dispersal. The history of the investigation of the genus is sym-
bolical of the history of its specific differentiation as a single wide-
ranging variable type. At first, when the known forms were few,
the genus was often regarded as monotypic, or as holding only one
species with fixed geographical varieties in the Old and New Worlds
and typified in Cakile maritima, the well-known European form.
In the next stage each side of the North Atlantic was credited with
a solitary species. As the inquiry proceeded, more particularly
after Asa Gray had separated the two common American plants
from the European C. maritimay the balance of distribution was
transferred to the American side of the Atlantic. In that direction
the later investigations have in the main advanced ; and whatever
view we take of the limits of the species it cannot be gainsaid that
the genus is preponderantly American.

There is, however, a disconcerting lack of agreement amongst
later investigators as to the limits of the species. Most of the diffi-
culties seem to be due to the different results obtained from the use
of the leaf and fruit characters in the distinction of forms. Having
encountered such difficulties. Dr. Millspaugh made a discriminative
study of the fruits and seeds of the specimens in the principal herbaria
of the United States and defined the relations of the American
plants with those across the Atlantic, the results being published
under the title of Plantce JJtowance (Part I. a) by the Field Columbian
^Museum (Chicago, 1900). He distinguished ten species, eight being
American and two European, no species occurring as an indigenous
plant on both sides of the Atlantic. In the Index Kewensis, including
the supplements up to 1910, ten species are enumerated, of which
.seven are exclusively American; but only six of the species given
iby Millspaugh are named. The more recent investigators, including
iSchulz in Urban's Symholce Antillance (1903), seem to have laboured
towards the reduction of the species, and I note that Fawcett and
Ren die in their Jamaican Flora (1914) speak only of four species
in the genus.

However, these differences of opinion concerning the limits of
the species do not affect the distribution of the genus, which may be
regarded as restricted, with the exception of a representation in
the region of the Great Lakes of North America, to the western

MISCELLANEOUS PLANTS

185

and eastern sea-borders of the North Atlantic in tropical and tem-
perate latitudes and including the West Indian and Caribbean
region ; but the genus on the eastern side of the ocean does not seem
to extend south of Madeira and North Morocco. A curious feature
of the distribution is that the genus is not represented by indigenous
species on the Pacific shores of the American continent. Harshberger
gives no locality on those coasts; and Millspaugh regards the only
species which he locates on the Pacific side (C. edentula at Berkeley,
California) as introduced.

The uncertainty about the limits of the species does not make my
task an easy one. I have made the acquaintance in their homes
with three of the species in four different regions, namely, in the
south of England, in the Azores, in the West Indies, and on the Pacific
Coast of North America. The West Indian species, with which I
was familiar in Jamaica and in the Turks Islands is Cakile cequalis
(L'Her.), which has been united by Sehulz with two other species
(named after Cuba and San Domingo) in C. lanceolata. The fusion
somewhat extends the range of C. cequalis, which already had the
reputation of being the most characteristic and widest spread of
the Antillean species. Thus extended, the range covers the Greater
and Lesser Antilles, including the Bahamas and the Florida keys,
and reaches to the Bermudas. It comprises also the continental
coasts of the Mexican Gulf and the Caribbean Sea, past Yucatan to
Colombia. It is the species of the Turks Islands; but, except in
one island, it is there uncommon. I only noticed it on Greater
Sand Cay, where it was represented by a single clump, and on Grand
Turk, where it grows in abundance. Since it was found on Grand
Turk by Hjalmarsson in 1858, more than half a century before my
visit, it .would seem that it has long since attained the limit of its
colonising powers in the Turks Islands, its scanty distribution over
the group being probably due to the havoc executed by the breakers
of those tempestuous seas on the shores of most of the islands. In
Jamaica I observed it on the north coast and west end of the island,
at White River, St. Anne's Bay, Dry Harbour, and Negril; but
localities on the south coast are given by Fawcett and Rendle.

The species of the Azores is confined to one locality, Porto Pym
on Fayal. It is regarded by Millspaugh as introduced and as belong-
ing to Cakile edentula (Bigel.) ; but Trelease views it as referable
to C. americana (Nutt.). From Lowe's description of a common
species in Madeira under the name of C. maritima, it would seem to
be similar to the Azorean plant. Further particulars concerning this
matter will be found in Chapters XVII. and XIX. under the Azores.
The species observed by me in 1896 on the Golden Gate beach at
San Francisco was probably the same species that, as we learn from
Millspaugh, has been introduced into San Francisco Bay (C. edentula).
There seems to be no indigenous species on the Pacific coasts of the
New World ; and this disposes of the statement in my work on Plant
Dispersal (pp. 431, 432) that the genus is represented by indigenous
species on both sides of North America. My observations on Cakile
maritima, the common European species, are given in the work just
named. The few notes since made on the coasts of South Devon

186 PLANTS, SEEDS, AND CURRENTS

and Cornwall are concerned with its transient occupation of the
beaches in places usually within reach of the wash of the waves at
the higher tides. A few individuals occupy a beach for a season
or two, then disappear, and two or three or more years elapse before
the species again gets a footing.

An interesting feature in the distribution of the American plants
is the occurrence of two Atlantic coast species (C. americana and
C. edentula) on the shores of the Great Lakes. Here in the society
of other beach plants of the same Atlantic beaches, such as Lathyrus
maritimus, Euphorbia polygonifolia, Psamma arenaria, etc., these
maritime species have found a home on the borders of inland fresh-
water lakes. This invasion of what is now the interior of a continent
is regarded by Harshberger (p. 222) as having taken place during
the post-glacial submergence of these regions. Such a change of
station throws some suspicion on the determining influence of the
halophilous inclination when it is so readily thrown off. In this
connection one is inclined to recall Kearney's discovery that the
amount of salt in sea-beaches is a negligible quantity, and to ask
oneself what constant character in the organisation of Cakile plants
we can associate with the double station on a sea-beach and on the
shores of a fresh-water lake. (For comment on Kearney's discovery
see Harshberger in Proc. Amer. Philos. Soc, 1909.)

That the currents are active dispersers of these plants may be
inferred from their frequent occurrence in isolated islands, as exem-
plified below in the case of Cakile lanceolata, though from facts to
be subsequently given it may be doubted whether the most buoyant
fruits could safely cross a tract of sea more than 300 or 400 miles
in width. The difficulties likely to be encountered before a footing
can be obtained on an island in the open sea have already been
mentioned in the case of the Turks Islands. But they are also
illustrated in the case of the Florida sand-keys which are for the
most part curving sand-banks, raised three or four feet above the
sea. Although Mr. Lansing noted the occurrence of Cakile fusi-
formis on twelve of the nineteen keys examined by him, the species
was as a rule merely represented by a few scattered clumps, and
in only two or three instances was it fairly frequent. Always it
formed the outposts of the sand- vegetation on the weather side of
the key. But Cakile may experience the same difficulties on Euro-
pean beaches in obtaining a footing beyond the reach of the waves
in stormy weather. What the waves give, they can also remove,
was the lesson taught to me by Cakile on English beaches.

On a long beach on the north coast of Cornwall it would be typically
represented by solitary clumps of C. maritima lying far apart and
all below the highest line of drift. They are derived from stranded
fruits that have germinated in the drift, of which results may be
seen in the numerous seedlings growing in the midst of the rubbish
heaped up by the waves. It is in the upcast wrack of the Norwegian
beaches that this species of Cakile flowers and fruits (Semander,
p. 123).

Cakile lanceolata is the West Indian species most characteristic
of small isolated island-groups. Thus it occurs in the Cayman

MISCELLANEOUS PLANTS

18T

Islands, on the Alacran Shoals, and in the Bermudas. That the
Bermudas received their representatives of the genus through the
currents is the opinion both of Hemsley and Millspaugh. Though
its capacity for dispersal by this agency is variable, as is shown in
the table below, it is significant that the species which has made its
home in Bermuda is the plant that may exhibit the greatest buoyancy
in its fruits. Yet in this there is a difficulty, since the drifting
passage from the West Indies to Bermuda would occupy ten or
twelve weeks (see Note 14 of the Appendix); whereas my experi-
ments indicate that under the most favourable conditions the fruits
of C. lanceolata would on the average float for only three or four weeks.

A similar point is raised by the occurrence of Cakile maritima, the
European species, in Iceland. It is shown in my experiments that
its fruits are not suited for crossing a tract of sea much over 100
miles in width, whilst the Faroe Islands, the nearest land to the
eastward in the direction from which they must have come, are
almost 250 miles away, and a drifting passage against the prevailing
winds and currents is involved. It would be easier for fruits of
West Indian species of Cakile to reach Iceland in the Gulf Stream
drift so often cast up on its shores than for those of C maritima to
traverse the distance that separates it from Europe, provided that
the fruits possessed in both cases the floating power. But the passage
from the West Indies would occupy many months, and the unfavour-
able climatic conditions would in themselves inhibit the establish-
ment of a West Indian plant. A clue may be offered when we
regard the associates of C. maritima on the Icelandic beaches, namely,
Armeria maritima, Glaux maritima, Lathyrus maritimus, Matricaria
maritima, Mertensia maritima and Silene maritima (see Babington
in Journ. Linn. Soc, XI., 1871). From the data for five out of these
six associates given in my book on Plant Dispersal, it is to be inferred
that only two of the plants, Lathyrus maritimus and Matricaria
maritima, would have reached Iceland by the currents. In the case
of Mertensia maritima, about which I possess no data, dispersal by
currents would seem most unlikely. Three or four of the associates,
which occur on both sides of the Atlantic and extend into Arctic
latitudes, raise quite other questions than those of dispersal. On
the whole I am inclined to hold that the Icelandic strand flora, in
which the genus Cakile takes a part, mainly reflects the effects of
past changes in circumpolar distribution and is but little concerned
with the currents.

Taking the case of Cakile lanceolata as representing both potentially
and actually the limits of possibilities for the dispersal of the genus
by currents, we may, I think, accept the conclusion, which is war-
ranted by the facts given below, that currents may effectually dis-
tribute the plants along continental coasts and between islands
100 to 200 miles apart. Currents will not explain the existence of
the genus on both sides of the North Atlantic. We must look for
the explanation in a common centre of dispersion of the genus in
Arctic latitudes when warmer climatic conditions there prevailed.
In other words, we must appeal to the theory advocated by Dyer
which is discussed in Chapter XV.

188 PLANTS, SEEDS, AND CURRENTS

Coming to the mode of dispersal of this genus by the currents
it may be at once observed that it is the upper article or joint of the
fruit that is alone concerned. It is deciduous and readily detached
from the dry fruit, whilst the lower joint remains firmly fixed to the
stalk on the plant. The buoyancy arises from the development
of spongy air-bearing tissue in the upper article, which is very light
when dry and buoys up the enclosed seed which itself sinks in sea-
water. As shown in the subjoined table, the floating capacity will
usually allow the seeds to be carried between 150 and 200 miles.
Flotation in sea-water, as indicated by my experiments on the fruits
of C. lanceolata and C, maritima does not affect the germinative
capacity of the seed, nor in fact does prolonged immersion after the
fruits have sunk afl;ect it. Martins found that germination took
place after fruits of C. maritima had been in sea- water for forty-five
days, though it is more than doubtful, as is brought out in Note 4
of the Appendix, whether they floated for more than a fraction of
this period. In my experiments germination occurred with fruits
of C. lanceolata that after floating for a week had lain for several
days at the bottom of the vessel. The lesson of the experiment
of Martins is that a submersion of forty-five days in sea-water will
not destroy the germinative capacity of the seeds of Cakile.

The restricted floating capacity arises from a weak point in the
buoyancy equipment. The suture between the lateral halves of
the joint is exposed in the face of the articulation at its base; and
it is here that the water ultimately penetrates into the interior and
deprives the article of its floating power. In old weathered fruits
this suture becomes more or less patent in the face of the articulation
and there is a slit-like opening. From this cause the buoyancy of
the joints is not always constant, as is shown in the different behaviour
of those of Cakile lanceolata obtained from Jamaica and the Turks
Islands.

Nevertheless, although the buoyancy as a rule is limited, there is
abundant evidence in the beach-drift of different regions that the
currents are effective agents in dispersing the fruits over limited
tracts of sea. I found the joints of Cakile to be characteristic con-
stituents of the smaller beach-drift in the south-west of England
(Cornwall and Devon), in Jamaica, and in the Turks Islands. Ser-
nander also alludes to them as occurring plentifully amongst the
Scandinavian beach-drift (pp. 122, 156, etc.). In all these localities
several of the stranded fruits were observed to be in a germinating
condition, and not infrequently seedlings were to be noticed growing
among the stranded drift- materials.

One may here direct attention to the very interesting suggestion
made by Dr. Millspaugh that the differentiation of the species of
Cakile is a response to the requirements of dispersal by currents.
" The evolution for floatage " (he writes) " seems to have reached
its height in the new species growing upon the Alacran Shoals "
(C. alacranensis of Millspaugh). Here there is a great development
of spongy tissue in the upper joint ; and it is argued that " the
species-generating force in the genus seems to have been the develop-
ment of the fruit for disseminating the plants." Prolonged investiga-

MISCELLANEOUS PLANTS

189

tion and an abundance of fresh materials would be needed before
one could discuss this important point.

In the table subjoined are incorporated the results of the author's
flotation experiments on the upper joints of different species of
Cakile from several regions. It may be inferred from the data
there given that the floating powers may vary considerably even in
the same species. In two of the columns the results are applied to
the transport by currents. A drifting rate of fourteen miles a day, or
one hundred miles a week, is taken as representing the usual distance
that would be covered under favourable conditions.

Cakile Flotation Experiments

Results of experiments by the author on the floating capacity in sea-water of the
upper joints of the fruits of different species of Cakile. (See explanation above
given.)

Species of Cakile

Locality of
Collection

Flotation Period
in Days

Capacity for
Transport by Ciu:-
rents stated in
miles at the rate

of 14 miles a
day, or 100 miles
a week

Age of the Fruits
when collected

Aver-
age

Maxi-
mum

Aver-
age

Maxi-
mum

C. maritima .

Cornwall

7

10

100

140

Recent

Cornwall

7

9

100

130

Seven months

Devonshire

7

10

100

140

Recent

C. lanceolata

Jamaica

25

35

350

500

Recent

Turks Islands

3

5

40

70

Recent

Turks Islands

5

7

70

100

Fifteen months

C. edentula .

Azores

9

12

130

170

Recent

The number of fruits experimented on ranged from six to fifteen. The term " re-
cent " is applied to fruits that were experimented on at periods varying from a few
weeks to two or three months after they had been gathered in the dry state from the
plant.

Additional Experiments.

The buoyancy in sea-water was also tested in the case of some fruits (upper joints)
of the following species very kindly sent to the author by Dr. Millspaugh. As they
had been collected several years before, and since only three fruits could be used in
each experiment, it seemed best to separate the results from those given above. The
maximum results obtained for the flotation period were as follows —

Cakile americana from Lake Michigan 5 days.
C. edentula from Lake Michigan 12 days.
C. alacranensis from the Alacran Shoals 20 days.
C. fusiformis from Dog Key, Mississippi 21 days.

Canavalia obtusifolia, DC.

This creeping or climbing plant has established itself on the beaches
of the warm regions of the globe, for instance, on the Pacific and Atlan-
tic coasts of tropical America, on both the east and west shores of

190 PLANTS, SEEDS, AND CURRENTS

tropical Africa, in the islands of the Indian Ocean, in the Malayan
Islands, and in Polynesia. With the exception of the African
coasts, which I have not visited, it came under my notice in all
the above regions. It ranks with Ipomoea pes-caprce as one of the
most ubiquitous of tropical strand plants.

Yet, in spite of its world-wide distribution in tropical regions and
of the fact established by observation and experiment that the seeds
are dispersed by currents, the seeds present a strange fickleness
of behaviour under the test of experiment. The plant has been
discussed in detail in my book on Plant Dispersal; but I will here
allude to the results of buoyancy experiments given in that work
(p. 579). Of freshly gathered seeds placed in sea-water in Fiji
only 10 per cent, as a rule floated after three months. Of seeds
which had been kept for three years 50 per cent, floated after eleven
weeks. In an experiment on recently collected seeds in Jamaica
40 per cent, floated after a month. The explanation of this behaviour
is that on the average only 70 per cent, of the seeds are impervious
to water, a result obtained from more recent experiments and re-
corded in the author's Studies in Seeds and Fruits (p. 94). But the
proportion of impermeable seeds varies considerably, being sometimes
more and sometimes less ; and at any rate the impervious seeds can
float for long periods. The impermeable seeds retain their germinative
capacity for a long time. Prof. Ewart found that seeds, sixteen
years old, were able to germinate, though sulphuric acid was required
to start the process {Ibid., p. 96).

The seeds were commonly observed by me in the drift of the
Fijian beaches and also on the coast of Ecuador, as well as on both
sides of the Isthmus of Panama, the plants being usually noticed
in the vicinity. I found them afloat in the drift of the Rewa estuary
in Fiji, and they were collected by Moseley amongst a number of
other floating fruits and seeds off the coast of New Guinea (Chall.
Bot., IV., 291 ). Though neither the seeds nor the plants were observed
by Treub on the shores of Krakatau three years after the great
eruption of 1883, the plant was found established by Penzig in 1897
and by Ernst and others afterwards. I came upon the seeds in
the beach-drift of different parts of the Jamaican coast, and they
were obtained by Morris from the beaches on the south side of the
island (Chall., Bot. IV., 291). They also came under my notice on
the beaches of St. Croix, Tobago, and other islands.

The plant is universally distributed in the West Indies, and there
were few beaches visited by me that did not display it. It occurs
all round Jamaica, and I found it on nearly every beach examined
on the north, south, and west sides of the island. It was rarely
observed growing away from the coast. However, in Tobago I
noticed it a mile inland and about 250 feet above the sea. In the
Turks group it is very rare, and was only remarked on two of the
ten islands — namely, on Salt Cay on the east side, where a fair-sized
colony was thriving on the beach, and on Grand Turk, where it was
represented only by a solitary seedling growing in the beach-drift
and evidently derived from a seed thrown up by the waves. Accord-
ing to Millspaugh it was recorded by Lansing from seven of the nine-

MISCELLANEOUS PLANTS

191

teen sand-keys lying west of Key West off the Florida coast ; but in
all but two cases it was only represented by a single colony. The
plant grows commonly on the Bermudian beaches.

It would be unnecessary to give all the data relating to the wide
distribution of this shore plant in the warm regions of the New
World; but a reference to a few localities which have particular
interest may here be made. In the first place, its occurrence on the
Pacific coast is not usually stated. However, I found it on the
Ecuador coast at Puerto Bolivar and on the beach at Panama.
Then, again, Harshberger includes it among the strand plants of
the delta of the Mississippi and of the Louisiana coast {Phyt. Surv.
N. A., pp. 215, 444). In some localities it grows in great profusion.
Thus Millspaugh at Santurce, Porto Rico, found it growing on sandy
fields near the sea " in great quantity, massing the surface of many
acres " (Planter Utowance). Amongst interesting insular localities
may be mentioned Fernando Noronha. Though it was not recorded
by Hemsley amongst the collections made by Moseley during the
voyage of the Challenger (1873-76), Ridley observed it growing
plentifully in 1887 (Journ Linn. Soc., vol. 27).

It may be remarked in connection with the statement now and
then made that the floating pods assist in the dispersal of the species,
that this would not happen under normal conditions. The pod
dehisces on the plant and often discharges its seeds with some force,
a habit common with legumes, where the valves develop a spiral
twist when drying. A detached fruit which I had placed in the sun in
Tobago burst with an explosion like that of a pistol and threw the
seeds ten to twelve feet away. Should an unopened pod be torn
from the parent plant and carried off by the waves, the attachment
of the valves would soon be loosened and the seeds would soon be
liberated and float away.

Cassytha filiformis, Linn.

CaSSYTHA AMERICANA, NCCS

Since Bentham unites the wide-ranging American form Cassytha
americana with the widely distributed Old World form C. filiformis,
we have here a species spread over the warm regions of the globe,
in Asia, Africa, America, and Australia, but chiefly, as Hemsley
remarks, in maritime districts (Chall. Bot., IV., 185). It is one of the
Dodder Laurels, a tropical genus holding at least fifteen or sixteen
species, of which two-thirds are Australian. It is noteworthy that
this species has been recorded from almost every group of the tropical
Pacific, from the Paumotu Archipelago and Tahiti to Fiji and north-
ward to Hawaii. When I met with it in the West Indies I renewed
acquaintance with a plant with which I had already been very familiar
in Hawaii and Fiji, the results of my numerous observations in the
Pacific being given in my previous book on plant dispersal in those
regions.

In Hawaii this parasite is occasionally found growing on the beach
plants, but it prefers the lower open-wooded region and especially
the surface of old lava-flows near the coast. In Fiji it is typically

192 PLANTS, SEEDS, AND CURRENTS

a shore plant, but it habitually extends far inland in the savannah-
like plains on the dry sides of the islands. It is, however, as a littoral
plant that it seems to be most frequently mentioned in the Old
World. In the Malay Peninsula, as we learn from Ridley, it is com-
mon in open sandy country near the sea (Trans. Linn. Soc. Bot.,
III., 267 ; 1888-94). On the numerous coral islands of the Java Sea
it grows very luxuriantly, covering the woody and herbaceous
plants wdth a felt-like coat (Schimper's Plant Geogr., p. 341, and
Ind. Mai. Strand Flora, p. 188). It is stated below that after the
eruption Cassytha filiformis established itself among the strand
plants of Krakatau. As Prof. Scott Elliot tells me by letter, it
crawls over the low bushes and covers the surface of coastal sand-
dunes in Madagascar. In the West Indies this plant occupies
similar stations. Whilst it is characteristic of the savannahs and
lower w^oods of Jamaica, it is also found at the coast. Millspaugh
observed it trailing over the beach sand-dunes on Cayman Brae
and in similar situations on Porto Rico {Plant. Utow.). In the
Bahamas it grows over the shore plants and is found in the thicket
formation inland (Harshberger's Phyt. Surv. N. Amer., pp. 691,
693-4). In South Florida it is a plant of the coastal dunes and
of the east-coast pinelands (Harshberger, Trans. W agner Inst. 1914,
pp. 70, 92, 93). Over the West Indian Islands this parasite is
widely distributed, and it ranges in the New World from South
Florida and Mexico to Brazil.

In the Pacific Islands I found that its small fruits, whether from
coast or inland plants, were able to float unharmed in sea-water
for months. On the other hand, fruits obtained by me from the
moist lower woods of Jamaica displayed no buoyancy, even after
being kept for years, the unfilled space in the fruit-cavity to which
the floating power is due being absent in this case. The floating
capacity is probably as a rule developed in stations where xeroph}i:es
thrive, as on the coast and in savannahs.

From its frequent station at the coast, and from its occurrence
in small coral islands, it cannot be doubted that the currents take
advantage of the buoyancy of the fruits to disperse the plant. As
long ago pointed out by Schimper frugivorous birds would also aid
in the distribution, the fruits in the moist condition being likely
to attract birds. In fact, fruits have been found in the crops of
pigeons shot in the Pacific Islands (Hemslej^ Chall. Bot., I., 46).
Whether birds or currents first carried the fruits to Krakatau after
the eruption of 1883 is not known. It appears, however, that
the plant was first recognised there in 1897, and that in 1906 it was
w^ell established amongst the strand vegetation (Ernst's Nezv Flora
of Krakatau).

It seems highly probable that this plant is a gift from the Old
to the New World through the agency of the currents. In this
respect the behaviour of the genus is closely similar to that of Sccevola
as described under the shore plants of that genus. Like Sccevola
the genus is predominantly Australian, eleven out of the sixteen
known species being peculiar to that region. Of the remainder,
three are peculiar to Africa, one is common to Ceylon and Borneo,

MISCELLANEOUS PLANTS

193

and lastly there is the cosmopolitan species we have been discussing.
Fawcett and Rendle, from whose work on the flora of Jamaica these
facts of distribution are taken, follow Bentham in regarding Cassytha
filiformis and C. americana as one species. The parallel between
Cassytha and Sccevola becomes still closer when we reflect that the
only species recorded from the New World is in each case the only
species that is common to the western and eastern hemispheres,
namely, C. filiformis and Sc. plumieri. A somewhat similar parallel
is offered by Dodoncea, another Australian genus, which is dealt
with under the head of D. viscosa.

In their suitability for being dispersed by frugivorous birds there
is another point of resemblance between the genera Cassytha and
Sccevola. In neither genus, however, could we often appeal to this
agency for trans-oceanic dispersal. In this respect I have somewhat
changed the point of view adopted in my previous work (p. 71).

Chrysobalanus icaco, L. (Coco Plum)

This shrub has a special interest, because it is not only widely
distributed in the tropics of the New World but also grows in West
Africa. It has an edible fruit, and its occurrence on the opposite
sides of the Atlantic raises much the same questions that are raised
by the Hog Plum, Spondias lutea, which has the same distribution.
Both have the reputation of possessing edible fruits, which, however, are
not very palatable in the raw state except to animals. With both
there is a suspicion that the aborigines may have aided their dispersal,
and in both the agency of the currents has been invoked. The
efficacy of the last agency is more assured in the case of the Hog
Plum, which is discussed at length in Chapter VI. ; but for the Coco
Plum the ground is not so certain, as is explained below. However,
it should be remarked that two eminent botanists, De Candolle and
Hemsley, basing their inference on general considerations, regard
the plant as dispersed by the currents, though the first named
looks upon the interference of man as equally probable {Geographic
Botanique, pp. 784, 792; Chall. Bot., I., 43; IV., 279).

From the data given by various authorities it is apparent that
Chrysobalanus icaco ranges in the New World from South Florida
and the Bahamas through the West Indian region to Trinidad, and
from Mexico through Central America by way of Venezuela to Brazil.
It evidently grows on all the larger West Indian islands and on most
of the Lesser Antilles. In the New World the species may be viewed
as possessing two forms, an inland form restricted to that hemisphere
and a coast form found also in tropical West Africa. The inland plant,
originally differentiated as C. pellocarpus, Mey., frequents moist
woods; whilst the coast plant is a typical shrub of the vegetation
lining the beach. (I have here followed Fawcett and Rendle in
their union of the two species in their Jamaican flora. This was the
view of De Candolle, and the exigencies of distribution long since
compelled me to support his opinion.)

We must therefore expect to find very different stations assigned
to this shrub. This is illustrated in Jamaica, where, according to
o

194 PLANTS, SEEDS, AND CURRENTS

Fawcett and Rendle, it may be found on the seashore and inland
at elevations up to 3000 feet. Disregarding its inland stations, I
will here refer to my observations on its occurrence at the coast
on this island and to those of others in the West Indies and in West
Africa. It is instructive to notice its associates, and they are suf-
ficiently varied to cause reflection. At Falmouth (Jamaica) it grew
on the drier ground of the coast flats behind the Batis-Salicornia-
Sesuvium association of the muddy borders of the mangrove belt,
and in the company of Guilandina bonducella, Coccoloba uvifera,
and Borrichia arhorescens. On the south side of the island, to the
east of the Black River and opposite the Salt Lakes, it grew on a
strip of sea-beach fronting the inland marshes in the society of a
Pancratium, and served as the host of a conspicuous yellow-coloured
Loranth (Phoradendron), In the Virgin Islands it is found amongst
the trees bordering the beach, such as Coccoloba uvifera, Hippomane
manciiiella, and Thespesia populnea ; and in the Bahamas it grows
on Watling Island behind the Tournefortia-Suriana association in
the company of Genipa clusiifolia and Coccoloba uvifera (Harshberger,
Phyt. Surv. N. Amer., pp. 686, 690). On the beaches of South
Florida and on the dunes in their rear Coccoloba uvifera^ the Seaside
Grape, is still the constant associate of the Coco Plum, Chrysohalanus
icaco, an association on which light may be thrown when we deal
with the plant first named (Harshberger, t ide infra).

But it is apparent that Chrysobalanus icaco is also a characteristic
plant of the great fresh-water morass of the Everglades in the heart
of South Florida. There it thrives in the patches of forest, known
as the " hammocks,'' that rise up in the midst of the swamps and
serve as sanctuaries for the West Indian vegetation that ages since,
when the region of the Everglades was submerged beneath the
Gulf Stream, occupied low islands rising up in a shallow sea. It is
at home also in this swampy interior at the edge of the cypress
swamps and at the borders of streams. In the company of such
typical West Indian littoral and estuarine plants as Hippomane
mancinella (Manchineel) and Anona palustris, Chrysobalanus icaco
has been for ages a denizen of the Everglades (Harshberger in Trans,
Wagner Inst., Philadelphia, 1914, pp. 67, 70, 135, 172; and Phyt.
Surv. N. Amer., 1911, pp. 230, 698).

In the tropics of the African West Coast, where the Coco Plum
is stated to be very common, it figures as a characteristic littoral
plant. Writing of the coast near the mouth of the River Nun, Dr.
Vogel observed in his journal that " the strand is clothed with
jungle close to the sea, consisting of Chrysobalanus icaco and Ecasta-
phyllum brozcnei,'' the last named being also a West Indian littoral
shrub (W. J. Hooker's Niger Flora, 1849, pp. 35, 336).

In the dispersal of this species both birds and currents have played
a part. Although its fruit would attract pigeons and birds of similar
habit, we could only appeal to such an agency in the case of inter-
island dispersal. The protection of the relatively thin-walled stone
would of itself be insufficient to enable the seed to withstand with-
out injury a sojourn of several hours in a bird's crop, and this
unfitness would be emphasised by the imperfectly filled hole at

MISCELLANEOUS PLANTS

195

one end of the stone, which in time would admit the gastric
fluids.

My observations on the suitabiUty of the fruits for transport by
currents were made in Jamaica on coast plants. The drupaceous
fruits are about an inch long, have a crustaceous fleshy covering,
and enclose a prominently ribbed stone (nearly as large as the entire
fruit), the walls of which are about 2 mm. thick. Inside is a single
seed which does not quite fill the cavity, and it is to this empty
space that the buoyancy of the dry fruit is due. But the seeds
often fail in a large number of fruits. In one locality I found that
only 10 per cent, were seeded. In the case of more or less empty
fruits there will usually be found the remains of two seeds, and
investigation showed that each of the two ovules, forming the ovular
complement of the genus, had developed into seeds, which, after
attaining a size of 3 or 4 mm., aborted and shrivelled up. Such empty
fruits, though useless for purposes of dispersal, are readily transported
by the currents

The fruits in the form of the dry more or less bared stones rarely
occur in the Jamaican beach-drift, and when found are usually
empty. It was in this condition that I found most of the fruits
in the beach-drift of the Black River coast and of the coast near the
White River on the north side of the island. The fresh fruit floats
at first ; but I should not imagine that it would float for a long time,
unless the failure of both seeds had resulted in an empty seed-cavity.
The dried stones as they lie under the plants are much more buoyant.
Four of these selected stones, which had been gathered a few months,
were placed in sea-water After two months they were all afloat,
and of two cut open one proved to have a sound seed and the other
a rotting seed. I should greatly doubt, however, whether the
currents, where a period of flotation exceeding two or three months
is involved, would prove to be effective agents for the dispersal
across an ocean of any sound fruits. A canal, which at one end of
the stone leads into the seed-cavity, is merely filled with soft tissue
that would in time permit the penetration of sea- water, thus bringing
about the death of the seed.

As regards dispersal by currents, the absence of this plant from
such a well-examined group of islands as the Bermudas is significant,
since so many West Indian strand plants have been carried there
through this agency. Nor can we appeal to the presence in the
Bermudas of its constant West Indian associate, Coccoloba uvifera,
since its indigenous character is doubtful, a matter referred to when
dealing with that plant. It is highly improbable that fruits with a
sound seed could ever cross the North Atlantic with the Gulf Stream
drift, though one might expect to find occasionally on the shores
of Europe an empty stone or one with the seed decayed. Nor could
the fruits withstand the six or eight months' immersion involved in
a passage to West Africa in the Counter Equatorial Current, even
if such a traverse was feasible. The chances that the currents could
carry the stone with a sound seed from the New World to tropical
West Africa may be thus ruled out. On the other hand, a capacity
of floating in the sea for two or three months without injury to the

196 PLANTS, SEEDS, AND CURRENTS

seed would just bring these fruits within the scope of the agency
of the Main Equatorial Current as a carrier of drift from West Africa
to Brazil. Though the greater number would probably not survive
this test, the few that did so would find on the first sandy coast
congenial conditions for establishing the plant. Its spread over the
West Indian region through the influence of the same swift current
would naturally follow. But before considering the possibility
that the New World has derived this species from West Africa, a
few remarks may be made on the distribution of the genus.

There can be no doubt that the genus is preponderantly American,
whatever view we may take of the limitations of the species. Of the nine
species given in the Index Kewensis, five are peculiar to the New World,
three to the Old World (mainly Africa), and one is common to both
worlds. By some the species are regarded as fewer, but the American
preponderance remains. There is thus a basis of support for De Can-
dolle's original contention {Geogr. Bot., pp. 784, 792) that the species
common to both worlds, Chrysohalanus icaco, is American in origin.
On the other hand, this plant was regarded by J. D. Hooker and
Bentham as " possibly introduced " into America from Africa
(W. J. Hooker's Niger Flora, p. 336). We are thus on the horns
of a dilemma. If De Candolle is right, and certainly the ancient
story of the plant in the Florida Everglades gives support to his
view, it could not have been a gift from America to the Old World
under the present arrangement of the Atlantic currents. If Hooker
and Bentham are right, we can appeal to the currents, but we have
to face the facts that the genus is predominantly American and that
the plant in dispute has been for ages a denizen of the Everglades.
Then we have the singular feature, which Chrysohalanus holds in
common with several tropical genera existing in both worlds, a
feature indicated in the fact that the only species linking the western
and eastern hemispheres together are littoral plants that could
only cross the Atlantic by the agency of the currents in its narrowest
portion between Africa and Brazil, the implication being that Africa
would here figure as the giver and not as the recipient. The easiest
way out of this disconcerting situation may be to adopt the view that
we are not primarily concerned with means of dispersal, and that
the original centre of dispersion of the genus lay in the north. In
other words, the hypothesis advocated by Dyer may remove most
of our difficulties.

CHAPTER IX

MISCELLANEOUS PLANTS (continued)

CoccoLOBA uviFERA, L. (Seaside Grape)

This is one of the most familiar of the trees growing by the sea-
shore in the West Indies. It is able to adapt itself to a variety
of stations at the coast. Thus, it often grows among the trees and
shrubs lining the sandy beach, when it is associated with Chrysoba-
lanics icaco, Ecastaphyllum hrownei, Guilandina honducella, Suriana
maritima, Thespesia populnea, etc. But it is almost as much at home
on a low, rocky coast in the company of the Seven-year Apple (Genipa
clusiifolia), and may not infrequently be found in the mangrove-
border association, growing either with Conocarpus erectus on the
flanks of the Laguncularia fringe or with Avicennia on the mud-flats
bordering salt-water lagoons. Where low, sandy plains lie behind
the beaches, it may extend some distance inland.

It belongs to a genus peculiar to the tropics of the New World
and holding a large number of species, 140 and more, that find their
principal station in the mountain forests and on the open-wooded
plains of the West Indies, Central America, and tropical South
America. This shore tree, which varies greatly in size, is spread
over the West Indian region, ranging from South Florida and the
Bahamas to Trinidad, and extends along the eastern borders of the
continent from Central America to Venezuela, the Guianas, and Brazil.
It grows in the Bermudas, and, although it now behaves as an in-
digenous plant on the sandy and rocky coasts (Harshberger, p. 703),
it was marked in a list of plants furnished by the Hon. J. H. Darrell
about forty years ago to the Governor, Sir J. H. Lefroy, as from the
West Indies (Hemsley in ChalL Bot, I., 61). Unlike many other West
Indian littoral trees and shrubs it has not been recorded, as far as
I know, either from the Pacific coasts of America or from the West
Coast of Africa. Fawcett and Rendle, the most recent authorities,
restrict it to the eastern side of the New World, and I may add that
when examining the shore vegetation on both sides of the Panama
Isthmus, I noticed it only on the north side, as at Colon.

As a rule where the plant grows it is found in abundance. In the
West Indies I studied it as a shore tree at St. Croix, in numerous
places around the coasts of Jamaica, in the Turks Islands, on Grenada
and on Tobago. It was observed by Millspaugh in the Cayman
Islands (Plantce JJtowance), and its occurrence there is suggestive;

197

198 PLANTS, SEEDS, AND CURRENTS

but it would seem to belong to a late stage in the plant-stocking of
isolated small islands. From the circumstance that Mr. Lansing
recorded it from only one of the Florida sand-keys and regarded it
as introduced, it would not appear to be one of the early plants that
establish themselves on newly formed islets in these seas.

In my notes I have only recorded it from four of the islands of the
Turks Group, namely, on Grand Turk, Long Cay, Cotton Cay, and
Salt Cay; but where found it is usually abundant. Amongst other
localities on Grand Turk it grows in quantity in the interior of the
low-lying level region of the southern half of the island, where on
a sandy soil it is associated with shrubs or small trees, as the case
may be, of Bontia daphnoides, Dodoncea viscosa. Euphorbia vaginulatay
Sophora tomentosa, etc. : but here, as in other parts of the island,
it extends in places to the beach. It thrives on the edge of the rocky
plateau of Long Cay on the leeward side, where it is associated with
Genipa clusiifolia, the Seven-year Apple. In Cotton Cay it grows in
dense thickets on the rocky surface of the wind-swept eastern ex-
tremity of the island, the Seven-year Apple growing under its lee;
but the constant exposure to the strong trade-wind has compelled
it to assume a semi-prostrate, straggling habit of growth. Its be-
haviour in the Turks Islands closely corresponds with that in the
rest of the Bahamian region, where it grows not only on the sandy
and rocky shores, but on the dry plains in their rear, and is often
associated in coastal thickets with Genipa clusiifolia (Harshberger,
Millspaugh, etc.).

The fruits are of regular occurrence amongst the smaller drift of
beaches wherever the plants grow on the coast ; and not infrequently
they may be found germinating in the drift washed up by the waves,
together with seedlings derived from the stranded fruits. The
fallen fruits lie in numbers under the trees lining the beach, and they
could be easily swept off by the waves at the higher tides. They
germinate in numbers on the ground beneath the trees, and numerous
seedlings are to be seen striking into the sandy soil. This inclination
to rapid germination on the soil would militate against the chances
of effective dispersal by currents, since seeds that germinate easily
would, as a rule, be imperfectly protected against the penetration
of sea-water, and in many cases these fruits, when swept off the
beaches by the waves, would be in the early stage of germination.

We come now to the methods of dispersal. The purplish, fleshy
fruits, 15-20 mm. long, at once suggest the agency of frugivorous
birds; and it is in this fashion that Hemsley considers the over-
seas dispersal of the plant may be explained {Chall. Bot. Intro., p. 49).
In this connection it is noteworthy that Coccoloha laurifolia, one
of the species that come next to C. uvifera amongst the West Indian
species with wide ranges, is known in Florida as the Pigeon Plum
(Fawcett and Rendle). Pigeons would probably be effective agents
of local dispersal or of inter-island distribution across narrow tracts
of sea; but it is very doubtful whether they would be effective
for long ocean traverses that could not be accomplished by a bird
in a few hours. The defects in structure that unfit the fruit for
prolonged flotation in the sea, as below described, would also render

MISCELLANEOUS PLANTS

199

it less able to withstand the injurious influence of the digestive
fluids of a bird for many hours.

Though in appearance drupaceous, the fruit is described by-
botanists as a nut whoUy enclosed in the fleshy accrescent perianth.
When the fleshy covering has been removed, the nut is seen to con-
sist of a hard shell containing a kernel enclosing an embryo with
foliaceous cotyledons in a ruminate albumen. From the history of
such a structure alone, one would be inclined to doubt the imper-
meability of the seed-vessel. In this case the nut has a thin crustace-
ous shell with an outer membranous skin, the shell being wanting
at the lower end of the fruit, which seems to be a character of the
family. The gap in the shell is filled up with softer tissue almost
like a plug; and it is here that the place of weakness as regards
impermeability to fluids lies.

Neither the entire fruit in its moist, fleshy coverings, nor the
freshly removed nut have any floating power; but after the fruit
has dried up on the ground it acquires buoyancy. It is in this con-
dition, with the withered outer coverings more or less removed by
insects and other agencies, that one fiAds these fruits under the trees,
the floating power being largely due to the fibro-membranous
covering investing the shell, and to its association with spongy cellular
tissue at the lower end. In Jamaica I made three experiments in
sea- water on the dried fruits gathered from under the trees in different
localities. In the first experiment half remained afloat after nine
days. In the two others 50 and 60 per cent, were floating after a fort-
night's immersion. The respective extreme limits of the floating
capacity in the three experiments were two weeks, four weeks, and
seven weeks. But water had always penetrated into the seed-cavity
of the sunken fruits, and as the fruits soon turned the sea-water
putrid, it had to be changed daily, results far from indicating any
special fitness of the fruits for prolonged transport by the currents.
On the whole I would infer that the penetration of sea-water would
in the course of a few days or weeks render these fruits quite un-
suited for effectual distribution over the ocean, and that although
they would float for a few weeks the germinative capacity would be
lost, as a rule, in a week or two.

A practical inference from these results is that Coccoloha uvifera
could scarcely have reached the Bermudas with the aid of the currents.
The same objection on structural grounds must be raised to the view
that the fruits could withstand the influence of the digestive juices
of a bird during its passage across 800 miles of sea by the shortest
route to the Bermudas from the Bahamas. The view of the residents
that the tree has been introduced in later years is probably correct.

From the foregoing remarks it would appear that a stretch of
from 100 to 200 miles of sea would be all that either the bird or the
current could accomplish in aiding the disposal of Coccoloha uvifera.
Yet the defects of the fruit that limit its capabilities for dispersal
are generic characters. It is, therefore, scarcely likely that any inland
species could be better adapted for distribution by birds, whilst in its
station alone it would lack opportunities for distribution by currents.
We could not go far wrong if we argued that in Coccoloha uvifera

200 PLANTS, SEEDS, AND CURRENTS

we see at their best the capacities of the genus for dispersal. Yet
measured by the geographical range they have produced effects in
some inland species (species that could have owed but little to cur-
rents) which give the inland plants a rank near that of C. uvifera.
Thus, in Jamaica, out of nineteen species enumerated by Fawcett
and Rendle eight have been recorded from outside the island. Four
of them, excluding C. uvifera, are inland, and often mountain, species
that have a distribution in the West Indies nearly as wide as the
species just named, and three of the four reach the South American
continent. It is, therefore, apparent that currents have not endowed
C. uvifera with a much greater range than is possessed by some
inland species that could owe nothing to currents; and it is quite
likely that currents have not been the principal agent in its dispersal.

CoLUBRiNA ASIATICA, Brongn.

This littoral shrub is discussed at length in my book on Plant
Dispersal, and I have there dwelt on the suitability of its buoyant
seeds for dispersal by currents and on their occurrence in river- and
beach-drift in the Pacific islands. It is distributed over the warm
regions of the Old World including the African East Coast; but
I have found no reference to its occurrence on the West Coast.
Grisebach gives it as a West Indian plant, but for Jamaica only.
It should, however, be at once observed that not one of the several
other authorities consulted (Hemsley, Urban, etc.) mentions it as
occurring in the West Indies or in the New World, so that we seem
to have here the same difficulty that, as shown in a subsequent page,
is presented by Thespesia popubiea.

I found it in fruit growing abundantly beside a beach at Dry
Harbour on the north coast of Jamaica, where it was associated with
such characteristic strand trees and shrubs as Coccoloba uvifera,
Conocarpus erectus, Guilandina bonducella, and Suriana maritima,
and it was the most frequent of them all. The seeds are indistin-
guishable from those of the plant in the islands of the Pacific and
display similar floating powers.

It may be that the difficulty lies in the species being very rare
in the tropics of America. The genus, which consists of twelve to
fifteen known species, is mainly American, a fact that in itself should
cause us to hesitate in excluding it from the New World, an opinion
expressed by the writer in his book on Plant Dispersal (p. 563) before
he visited the West Indies. As tested by him in Fiji, the seeds of this
species float unharmed in sea-water for many months, and they
are even better fitted for dispersal by currents than those of many
other littoral plants. There are, at least, two West Indian species,
Coluhrina ferruginosa and C. reclinata, that are widely spread in that
region and may be found occasionally in littoral stations (Grisebach,
Urban, Millspaugh).

We may add that Coluhrina asiatica figures amongst the later
accessions to the flora of Krakatau, its seeds being derived from the
neighbouring coasts, where it thrives (Ernst).

MISCELLANEOUS PLANTS

201

CONOCARPUS ERECTUS, L.

This small tree, which finds its most characteristic station at the
drier borders of mangrove swamps, has the distribution of the
American mangrove formation, occurring on the Atlantic and Pacific
shores of the New World and on the West Coast of Africa. Though
not one of the mangroves, it is a constant associate of those plants
and ranges with them throughout the West Indian region, reaching
north to South Florida on the Atlantic side and to Lower California
on the Pacific side, and following the mainland south to Ecuador
on the west and to South Brazil on the east. Its occurrence on the
Pacific coasts of tropical America is noted by Hemsley (Chall. Bot.,
II., 32). It was observed by myself on the coasts near Panama,
and also on the shores of Ecuador, where it was also noticed by
Baron von Eggers. In my book on Plant Dispersal I omitted, on
page 488, to include it amongst the vegetation of the beach of Jambeli
Island off the Ecuadorian coast. Millspaugh (Plantce Utowance)
and Harshberger (Phyt. Surv. N. America) give it two localities in
Lower California, and the former adds Acapulco on the Pacific coast
of Mexico. Its ability to establish itself on isolated island groups
is shown by its existence on the Alacran Shoals and the Cayman
Islands (Millspaugh), and particularly by its occurrence in the
Bermudas and in the Galapagos Islands.

Grisebach includes the Marianne Islands (Ladrones) in his list of
localities. Its occurrence there, though far from impossible, is
scarcely probable, since it has not been found on any of the archi-
pelagos in the Pacific excepting the Galapagos Islands. Dr. Rendle
suggests that there may have been a misreading of the locality,
since there is in the Herbarium of the British Museum an old specimen
from Menzies labelled " Marias I", San Bias," off the west coast of
Mexico (letter cited).

This species is a most variable one, a behaviour which is evidently
in response to the different stations in which it is able to thrive,
since, as shown below, though most typically at home on the borders
of the mangrove it can accommodate itself to almost every kind
of station that a coast can offer. It presents all gradations between
a prostrate trailing shrub and a moderate-sized tree, usually exhibit-
ing itself as a shrubby tree seven to ten feet high. Grisebach gives
three varieties, and Millspaugh makes five {Plant. JJtow.) ; but doubtless
there are more. The prostrate forms generally grow on rocks.

All West Indians know the Button-tree, as they call it. In Ber-
muda it is termed Button-wood and also Wild Mulberry, from the
changing colour of its fruits, first white, then reddish, and then
brown. But its singular roundish fruits are much more like the
cones of the Alder. In fact, Alnus maritimum was one of its earliest
botanical names, and Alder-tree is still one of its West Indian names.
Grisebach also gives, as another of its appellations, Zaragoza Mangrove,
I suppose from some place on the shores of the Spanish Main. I was
familiar with it in a number of places, wherever, in fact, the man-
groves came under my observation, as on St. Croix, Jamaica, Turks
Islands, Trinidad, Colon, Panama, and the coast of Ecuador, etc.

202 PLANTS, SEEDS, AND CURRENTS

Though not a mangrove, it nearly always accompanies the forma-
tion; yet it can accommodate itself to the dry, sandy beach or to
the dunes behind, to a muddy flat, and even to a rocky shore. Its
various stations are well illustrated in Jamaica, where it occurs all
round the island; but rarely can one dissociate it altogether from
the surroundings of a mangrove swamp; and in most cases where
it grows on a sandy beach fronting the coast a mangrove swamp lies
in the rear of the beach. Though in Jamaica and in other islands
it may be found growing on a typical dry, sandy beach and on a
rocky coast, it is around the mangrove borders immediately skirting
the Avicennia and Laguncularia trees, which form the margin of
the formation, that it finds its most typical station. In this con-
nection it often skirts a mangrove swamp on the land side, and
when it is found on the seaward side it is usually growing on a thin
strip of sandy beach thrown up by the waves. It is often mixed up
with Laguncularias and Avicennias on the exposed muddy shores
of lagoons communicating with the sea. Quite remarkable is its
frequency in the Black River Morass. Here, though it seemed to
prefer drier ground, it might be observed two miles inland associated
with Typhas and tall sedges. Its variety in coastal stations is well
illustrated in Harshberger's work. But it is to its association with
the outer mangrove gro^vth of Avicennia nitida and Laguncularia
racemosa that he chiefly refers, as in the case of Cuba, the Virgin
Islands area, the Bahamas, and the Californian Peninsula, the
designation of " Conocarpus-mangrove formation " being employed.
Yet he speaks of its growing, either prostrate or in dwarfed con-
dition, on coastal rocks in Bermuda and in the Bahamas; whilst
in the locality first named it forms thickets on the dunes.

All its capacities for different stations are displayed in the Turks
Islands, and in fact they are all illustrated on Grand Turk; but
the destruction of much of the original extensive mangrove formation
on the two largest islands, Grand Turk and Salt Cay, has often given
prominence to stations away from the mangroves. However, in
the first-named island it is still to be seen associated with Lagun-
cularias on the land side of the swamps. On the rocky surface of
Long Cay it thrives in association with Borrichia arborescens ; but
it adapts itself to the great wind-pressure, to which it is there com-
monly exposed, by adopting a semi-prostrate habit, like several of
the shrubs (Tournefortia, Suriana, etc.) on these windward cays.
Here it clambers over the rocks, and is not more than one or two feet
in height. This is evidently the variety " procumbens " of Jacquin,
as given by Grisebach. It thrives on the weather side of Salt Cay,
both at the borders of the beach and on the dunes behind in the
company of Tournefortia gnaphalodes and Suriana maritima. It
may be one of the prevailing small trees or shrubs in the half-stony,
half-sandy interior of an island like Cotton Cay, where it is in the
company of the Turk's-head Cactus ; but even here it may be sur-
mised that its original station was around the central lagoon with the
mangroves that have since disappeared. This plant is one of the
marginal associates of the mangrove belt that are able by their greater
adaptability to survive the destruction of the mangroves at the

MISCELLANEOUS PLANTS

203

hands of man. Its capacity in this respect is cxempHfied on Gibbs
Cay, where it grows on the dry sandy slopes of the island. On half
of the cays that form the Turks Group, namely, on Round Cay,
Penniston Cay, Pear Cay, Eastern Cay, and Greater Sand Cay, the
plant was not observed.

The observations made by Mr. Lansing (and described by Dr.
Millspaugh) on the Florida sand-keys west of Key West, are of
interest in this connection, since the method of stocking newly
formed islands is there illustrated. Out of nineteen keys examined,
five displayed the plant; and it appears that where it is conspicu-
ously absent from a group of the keys, as in the Tortugas, this is
to be attributed to the fact that they lack the mangroves with which
this tree is usually associated. Yet it is rarely in great quantity on
any of these Florida sand-keys. Four out of the five possessing it
displayed only one or two moderate-sized colonies, and it was only
in the fifth that it was well represented. The station was nearly
always the same, namely, at the back of the vegetation of the exposed
sandy part of the islet and bordering the Avicennias that fringed the
great colonies of Rhizophoras.

Although it would be wrong, as Schimper also observes (p. 64),
to number Conocarpus erectus with the mangroves, it would be equally
wrong to place it with the typical trees and shrubs that line the
sandy beach. From the standpoint of station it comes between
the two ; but in the matter of its distribution it has the range of the
mangroves and accompanies them almost everywhere. When I
first met with this plant on the coasts of Ecuador and Panama,
its double station appeared very puzzling. But I found that this
was recognised by Baron von Eggers, who, whilst studying the
Ecuadorian strand plants, placed Conocarpus erectus in different
localities in the mangrove formation and in the sandy-beach flora.
This is the dilemma in which the plant frequently places the botanist,
and it is one from which he can free himself by investigating the
stages of the plant-stocking of newly formed islets in these seas.
Such an inquiry has been accomplished in the case of the Florida
sand-keys by Mr. Lansing and Dr. Millspaugh. The last-named
botanist makes a special association for this locality of the plants
of the mangrove borders, including Avicennia nitida, Laguncularia
racemosa, Conocarpus erectus^ etc. ; and he shows how in the case
of a young Rhizophora colony, recently established on a newly formed
sand-key, Conocarpus erectus may take the place of the usual Lagun-
cularia fringe.

The small scale-like achenes, which are gathered together in a
rounded cone-like fruit-head, readily become detached when the
head dries. They average about 4 mm. across and possess great
floating power. Although Schimper did not test their buoyant
capacity, he rightly postulated it from their structure (Ind. Mai.
Strand Flora, pp. 170, 180), which he compares with that of I'er-
minalia fruits of the same family. Within the thin, impervious, shell-
like outer skin there is an extensive development of spongy air-
bearing tissue, and within this is the seed protected by a hardened
layer of the endocarp. No part of the fruit or seed has any floating

204 PLANTS, SEEDS, AND CURRENTS

power, except the spongy tissue. A number of the achenes were
placed in sea- water in Jamaica, and after two months they all floated
buoyantly and contained in some cases sound seeds. Evidently
they could float for a long period, and could certainly be carried by
the Equatorial Current across the Atlantic from West Africa to
Brazil.

But there is an important point to notice in this connection.
Although the plant fruits abundantly it oftens matures scarcely
any seed. One may examine a number of the achenes and find neither
seed nor stone, or at all events only in a few cases, as in a sample
from the Turks Islands, where only 3 or 4 per cent, contained a seed.
This was remarked by Schimper (p. 171), and he quotes Bentham
and Hooker to the effect that this is a frequent phenomenon. But
I should imagine that it rarely happens that one meets with the
experience of Schimper, who found every fruit examined to be seed-
less. Thus, whilst writing these lines, I have examined a sample
of fruits from Jamaica, and find about 10 per cent, seeded. As a
set-off against this defect in seeding one must place the abundant
fruiting of the plant. Taking the average number of fruit-heads on
a panicle at fifteen, and the average number of achenes per head
at thirty-three or thirty-four, then each panicle would contain 500
achenes and, taking the proportion of seeded fruits at 4 per cent.,
twenty seeds. Each small tree must develop a large number of
these panicles in a season. Suppose we place them at fifty, which
is probably below rather than above the average, then each plant
would mature a thousand seeds, which I imagine would be as many
as an ordinary Terminalia tree would mature in a single season.

Schimper undoubtedly regarded this plant as dispersed by the
currents, and the same position was taken by Hemsley in his discus-
sion of the Bermudian flora (Chall. Bot.^ I., 48). Millspaugh, however,
in his paper on the Florida sand-keys, regarded it as probably distri-
buted by birds. I think, however, that a good case has been made
for the currents. It may be noted in conclusion that there is every
reason for believing that it is truly indigenous, and that it reached
Bermuda with other West Indian plants characterised by Mills-
paugh as belonging to the association of the mangrove border.
Hemsley recognises this plant as probably one of the four that can
be identified from the description of Jourdan, who accompanied
the expedition of Sir George Sommers that was wrecked on the
Bermudas in 1609. It is noteworthy that three out of these four
early Bermudian plants, namely the Prickly Pear {Opuntia), the
Juniper (J. hermudiana), and the Palmito {Sabal hlackhurniana) had
evidently been established there through the agency of frugivorous
birds (Chall. BoL, I., 49; II., 3).

Crudya spicata, W.

In its range the leguminous genus Crudya presents most of the
difficulties offered by Chrysohalanus (p. 193). Out of fourteen
known species all are American with the exception of one African

MISCELLANEOUS PLANTS

205

and one Philippine species, the most important difference between
the two genera being that Crudya, unUke the other genus, has no
species common to both the American and African sides of the
tropical Atlantic. This difference is associated with the fact that
when we compare the two species of these genera that are most
likely to be dispersed by the currents, Chrysobalanus icaco of the
seashore and Crudya spicata of the fresh-water morass of the lower
levels, the only one that could perform an ocean traverse through
the agency of its floating fruits or seeds is Chrysobalanus icacOy the
West African shore plant. But even here the traverse of the ocean
is restricted by the limited floating capacities of the fruit to the
passage in the Main Equatorial Current from the Gulf of Guinea to
Brazil.

The distribution in the West Indies of the trees of the genus
Crudya, as indicated by Grisebach, is very interesting and provokes
inquiry. Three species are named, of which two are described as
frequenting swampy districts ; whilst the station of the third is not
mentioned. All occur in the Guianas, one of them (the species
under consideration) being found also in Jamaica and the other two
also in Trinidad.

It is with the species at home both in Jamaica and Guiana, namely,
Crudya spicata, that we are specially concerned, though it is highly
probable that the general features of its behaviour will be reproduced
by the other two species. This tree raises all the questions presented
hy Symphonia globulif era {p. 24!S) and Grias cauliflora (p. 211). It
is especially comparable with the first named, since both occur in
Guiana. All three plants are trees of the riverside. In all three
cases the trees add their fruits or seeds to the floating river-drift,
and in all three cases the floating fruit or seed is usually found in
the germinating condition. In not one of these three trees do the
means of dispersal explain the presence of the same, or, as in the
case of Grias, of closely allied species in the large West Indian islands
and in the South American mainland. All three species are in the
same sense " difficult " plants. They are all of the greatest signifi-
cance to the student of distribution, and in all of them he is forced
to admit that " means of dispersal " do not explain " range."

Crudya spicata, according to Grisebach, flourishes in the great
morass of Westmoreland in Jamaica, and Britton has more recently
referred to it in the same locality (Harshberger, p. 678). I found it
in that district on the banks of the Cabarita River in association
with Grias cauliflora. It also came under my notice on the banks
of the Black River near Lacovia. The flat ligneous legume, which
is about 3 J inches long and tardily dehiscent, contains one or two
large seeds which possess only thin, pervious, membranous coverings
that afford no protection against drying and but little against the
penetration of water. The pods are to be seen afloat in the river-
drift as well as the seeds ; the last owing their buoyancy to a large
central cavity between the flat cotyledons, the embryo itself having
no floating power. When the seeds occur in the floating drift, they
look rather like those of Entada scandens, and the Black River people
give them the same name of " Cacoon "; but they are readily dis-

206 PLANTS, SEEDS, AND CURRENTS

tinguished by their soft coverings. The floating pods are much
less frequent.

Quite 80 per cent, of the seeds afloat in the Black River drift were
in a germinating condition, a result not to be surprised at when we
reflect on the unprotected state of the seed. The germinating seeds
when carried down to the sea would soon be destroyed by the salt
water; whilst the few that had not begun to germinate would, on
account of their unprotected character, meet the same fate. The
buoyant capacity would, of course, be limited under any condition,
and the tendency of the seeds to germinate afloat would render them
quite ineffective for purposes of dispersal by currents. I did not
learn how the seeds liberated themselves from the pod, whether
on the tree or in the river. But it seems probable that in the last
case the pod takes up water, and that this leads to its rupture through
the swelling of the seeds. This appears to be indicated by the fact
that the seeds afloat in the river are too large for the pod as it grows
on the tree. The germinating seeds are thrown up in numbers on
the beaches near the Black River estuary, and shrivel up in the sun.
The pods were not to be found in the beach-drift, and evidently they
do not reach the sea.

Seeds of a species of Crudya are brought down by the Orinoco and
deposited in the germinating state with much other drift on the south
shore of Trinidad.

Some matters have still to be investigated relating to Crudya
spicata; but enough has been said to show that it possesses no
effective means for overseas dispersal. We cannot look there for
an explanation of its range.

DODON.«A VISCOSA, L.

This plant is discussed at length in my work on Plant Dispersal
(p. 338, etc.). Here, as there, Bentham is followed in the inclusion
within this species of nearly all the extra-Australian forms. In the
West Indies I renewed my acquaintance with this cosmopolitan plant,
more especially in Jamaica and the Turks Islands. The form that
I experimented on in Jamaica was Dodoncea hurmanni, DC. ; but,
as Grisebach observes, both this form and that of D. viscosa proper
grow on the seashore in that island. Since they occupy the same
stations and accompany each other over most of the warm portions
of the globe, both as littoral and inland plants, the facts of distribu-
tion would in this respect go to support Bentham's view of the com-
prehensive nature of the species.

The form above named grows in Jamaica among the vegetation
bordering the beach and on the drier mud-flats and behind the
mangrove fringe of the salt-water lagoons in the Black River district,
where it is associated with Conocarpus erectus, Coccoloha uvifera,
etc. Millspaugh speaks of Dodoncea viscosa growing on the sandy
beach at Grand Cayman (Plantce UtowancB), and Harshberger mentions
it as a dune plant in Bermuda (p. 703).

The dark round seeds, 2-5 to 3 mm. in diameter, float in sea-
water, their buoyancy being due to the unfilled space in the seed-

MISCELLANEOUS PLANTS

207

cavity, neither coats nor kernel having independent floating power.
Of some tested in Jamaica half were afloat after six and a half weeks
in sea-water, most of them with sound kernels. Schimper found
that seeds of D. viscosa floated from ten to sixty days (p. 165).

In the Turks Islands this plant only came under my notice on
Grand Turk. There, in the company of Sophora tomentosa and of
plants peculiar to this region, it thrives in the sandy interior of the
southern part of the island, but does not appear on the beach.

Dodoncea offers in its distribution much the same problem that
is presented by Cassytha and Sccevola as discussed in other pages of
this work. Here we have three genera, in great part Australian,
which are, however, represented over the warm regions of the globe
by one or two species typically littoral in their habit, but able in
the case of those of the first two genera to accompany xerophytic
plants far inland. Here we have a clue to distribution, which if
thoroughly investigated might lead to rich results, though it would
require many years of travel and research. It can only be said here
that my later inquiries in the West Indies go to confirm the general
inference given on page 341 of my previous work, namely, that in
the case of Dodoncea viscosa currents alone could not account for its
distribution in oceanic islands like Hawaii, and that if we placed
the agencies of dispersal in their order of effectiveness they would
be, first, granivorous birds, then the currents, and lastly man.

It may here be observed that this plant was found established
on Krakatau in 1906, more than twenty years after the great eruption.
It was also noticed on the neighbouring coast of Sumatra (Ernst,
pp. 17, 40). As one of the plants of the old dunes it is found near
the coast all over New Zealand, and has also reached the Chatham
Islands (Cockayne's Report on the Dune Areas of New Zealand, 1911,
pp. 30, 33).

ECASTAPHYLLUM BROWNEI, PcrS.

This small leguminous shore tree, which is not only widely dis-
tributed in the tropics on the American side of the Atlantic, but
occurs also on the West Coast of Africa, is one of the commonest
plants bordering the beach in these regions. It extends from
South Florida through the West Indies to Southern Brazil, and is
found on both the Atlantic and Pacific shores of Central America.
It is one of the plants that De Candolle regarded as at home in
America, but as naturalised in Africa. In West Africa, however,
it behaves as an indigenous tree; and when we read in Dr. Vogel's
journal quoted in Hooker's Niger Flora, that with Chrysohalanus
icaco it forms the jungle that clothes the strand near the mouth of
the River Nun, we are reading of the association of two typical West
Indian shore trees or shrubs in tropical West Africa. Both of them
were viewed by De Candolle as American plants naturalised in Africa
(Giogr. Botan., p. 792) ; yet both of them would be quite unfitted,
as regards their fruits, to accomplish in an effective state the long
drift involved in the passage from the American to the African con-
tinent by the Gulf Stream route. The only Atlantic traverse avail-

208 PLANTS, SEEDS, AND CURRENTS

able for them would be the shortest, namely, from the West African
coast to Brazil in the Main Equatorial Current.

I was familiar with this shore tree in different places, and especially
in Jamaica and at Colon; and its pods were a frequent constituent
of the drift on the beaches of those localities. The pods were amongst
the collection of beach-drift made by Morris in Jamaica, their seeds
appearing quite sound (Chall. Bot., IV., 300). When, however, we
examine their capacity for trans-oceanic dispersal by currents, we
find it insufficient. They are too fragile for withstanding the buffet-
ing involved in dispersal by ocean currents for more than a few weeks ;
and they soon begin to decay and to admit water, against which the
thin coverings of the enclosed seed could afford no protection. The
currents have been effective agents in establishing many of the West
Indian plants in Bermuda ; but this tree is not one of them. This
is very suggestive, because almost all of them are well suited for
dispersal by currents ; and the inference is that, though the currents
could carry these pods unharmed from island to island in the West
Indies, they have not been able to carry them in this condition to
the Bermudas. The agency of the drifting log could scarcely be
invoked, since, as we shall see, the question is not so much one of
buoyancy as of the inability of the pod to preserve the seed from
injury through the penetration of sea- water, and this danger would
still threaten a pod in the crevice of a drifting log. It is significant
that these pods did not come under my notice in the stranded drift
of the Turks Islands ; nor does the plant grow in the group.

The legume is a single-seeded, flat, somewhat oblique, oblong pod,
about an inch in length. It floats buoyantly in the dry state; but
it owes its buoyancy entirely to the air-bearing tissue in the walls
of the pericarp, the seed possessing no floating power and filling
the seed-cavity. But for purposes of prolonged oceanic transport
the pod is too fragile, and is not sufficiently impervious to water,
the thin seed-coverings also offering no protection against sea- water.
In appearance the pod does not seem much better fitted for with-
standing prolonged sea- water flotation than the dried pod of Pisum
sativum. Under the quiet conditions of two experiments made in
Jamaica, the pods showed no tendency to sink after a month's
flotation, but in some cases water had penetrated and the seed was
decaying, and there was little to indicate that the seed would retain
its germinative capacity after the pod had been exposed for more
than a few weeks to the " rough-and-tumble " of oceanic transport.

Erythrina

Reference may first be made to the supposed seeds of this genus
thrown up on the Orkney Islands and on the coasts of Scandinavia,
which are referred to in Chapter II. (pp. 23, 26). The Orkney drift
seed figured by the elder Wallace is evidently an Erythrina seed, and
the " Bent-stones " (Buesteen) of the early describers of Scandinavian
foreign drift may probably be placed here. Tonning, a pupil of
Linnaeus, includes Piscidia erythrina amongst the plants contributing
to the Scandinavian drift (Amoenitates Academicce , VII., 477, as quoted

MISCELLANEOUS PLANTS

209

by Hemsley in Chall. Dot., TV. ,278), and Gumprecht, employing the
same reference in page 420 of his paper, observes that Tonning
referred the Scandinavian " Buesteen " to Piscidia erythrina. This
leguminous tree, as shown below, is not at all likely to have furnished
the Bent-stone " seeds of the Scandinavian beach-drift; and it is
noteworthy that Sernander, the most recent writer on this subject,
who was doubtless guided by Lindman, excludes it from his list of
Tonning' s identifications.

Piscidia erythrina, L., is a West Indian tree, the seeds of which,
as described in Grisebach's work, are one-third of an inch long,
black, sub-compressed, and transversely oblong. They evidently
would not be described as *' Bent-stones " or "Curved-stones";
and it is very unlikely that they possess buoyancy. Though the
tree is common in the West Indies, its seeds have never been
recorded from the beach-drift.

There is, however, abundant evidence to show that the seeds of
littoral species of Erythrina, to which the name of Bent-stone would
apply, are dispersed by currents in the Indian and Pacific Oceans,
and I have dealt at length with the matter in my book on Plant
Dispersal (pp. 141, 435, 437-8, 489, 577). In those regions they
figure in stranded beach-drift and in the floating drift of rivers. In
the West Indies the species with buoyant seeds do not seem common
enough to enable them to figure in the beach-drift. But on the
South American mainland, as illustrated in the case of the estuaries
and beaches of Ecuador (Ibid., p. 489), Erythrina seeds are abundant
in floating and stranded drift, and may be observed miles out at sea
off the river mouths. A systematic inquiry into the buoyancy of
the seeds of the New World species of the genus is needed. I experi-
mented on those of Erythrina velutina and E. corallodendron, neither
of which are littoral species. In the first case most of the seeds have
buoyant kernels, two-thirds floating in fresh-water and nine-tenths
in sea-water. Of four seeds that floated in sea-water three were
afloat after a month. The seeds of Erythrina corallodendron displayed
no floating power and possess non-buoyant kernels.

Genipa clusiifolia, Gr. (Seven-year Apple)

This remarkable maritime shrub, which attains a height of from
four to six feet in the Turks Islands, has a Hmited distribution, being
restricted according to the authorities to Cuba, the Bahamas, and
South Florida, though its presence in Hispaniola would seem probable.
Although it is well distributed over the Bahamian region, extending
to the extreme south-easterly sub-groups, the Inaguas, the Caicos
Islands, and the Turks Islands, it has not been recorded from Ber-
muda. Its absence from the Florida sand-keys west of Key West
is of interest, since it grows on the Florida coast ; whilst this and the
other negative features of its range go to suggest a small capacity
for dispersal by currents. It belongs to a genus that is confined
to the warm regions of the New World.

Yet there is much to attract the student of dispersal in the " Seven-
year Apple," the name by which it is known aU over the Bahamian
p

210 PLANTS, SEEDS, AND CURRENTS

region. The origin of the name is obscure, and it promises to remain
in obscurity, since Catesby, who was in these islands about 1725,
remarks in his work on the natural history of this region (I., 59) :
" I know not for what Reason the Inhabitants of the Bahama Islands
call it the Seven Years Apple." In this connection it should be noted
that in January and February 1911, during my sojourn in the Turks
Islands, it was in flower and unripe fruit. Catesby states that it
ripens its fruit in seven or eight months. One may notice that the
name of " Seven-year Vine " is according to Grisebach applied in
the West Indies to Ipomoea tuherosa, a widely distributed plant with
an inedible tuber, dealt with in Chapter VI.

I found Genipa clusiifolia growing on four of the ten islands of the
Turks Group, namely. Grand Turk, Long Cay, Cotton Cay, and
Greater Sand Cay. On Grand Turk individual plants grew amongst
the rock masses at the foot of the bluff that rises in the rear of the
broad beach at the southern extremity of the island. It also grew
on rocky ground in the interior of the island in different localities,
as on the low hills around the North Wells; but I never noticed it
growing in colonies, as in some of the smaller cays. It composed
great thickets on the rocky surface of Long Cay on the lee or south-
west side, being associated with Coccoloha uvifera ; and it extended
to the edge of the low cliffs that form the border of the island. On
the eastern or weather end of Cotton Cay a few plants were associated
under similar soil conditions with dense thickets of Coccoloha uvifera
and a quantity of Phyllanthus falcatus. It occurred probably on
other parts of this island. On Greater Sand Cay it was one of the
most characteristic plants, especially in the northern half, growing
in colonies over the sandy and rocky surface, but not coming down
to the beaches. In all these localities the plant in the early part of
1911 was in flower and unripe fruit, the fruiting stage being most
pronounced.

This plant is truly littoral in its station. In Cuba, as remarked
by Grisebach, it grows on maritime rocks. Millspaugh writes that
it occurred on coastal rocks on all the Bahamian islands visited
(Proenunc. Baham.). Harshberger includes it in the Bahamian
strand formation, assigning it a station not only on the coastal
rocks, but also on the sandy ridges and mounds behind the Tourne-
fortia-Suriana association. He writes that it is an element of the
sandy strand formaton of South Florida (Trans. Wagner Inst. Phila-
delphia, Oct. 1914, p. 70; Phyt. Surv. N. America, pp. 690, 692).

The fruit is an egg-shaped berry, 2^ to 3 inches long, yellowish and
hard in the unripe condition, but reddening as it approaches maturity.
When ripe, as Catesby tells us, it is pulpy and has the consistence of
a mellow pear. (The fruits at the time of my visit to the Turks
Islands were full-sized, but still hard.) It possesses a thick rind
and a large number of dark-brown, flat crustaceous seeds, one-fifth of
an inch (5 mm.) long and lying horizontally in a relatively scanty
pulp. It is a curious fact that I never observed either withered
fruits on the plant or fallen fruits on the ground. It is probable
that they are much appreciated by the large iguanas found on some
of the cays ; and it is noteworthy that the two islands most frequented

MISCELLANEOUS PLANTS

211

by these reptiles, Long Cay and Greater Sand Cay, were the two on
whieh the plant was observed growin^r in greatest abundanee.

To my surprise the fruits approaehing maturity, though still hard,
floated buoyantly, the floating power lying in the thick rind or
pericarp, which is protected by a tough skin. Four of them were
placed in sea-water, where they floated for three weeks, when they
began to rot and the seeds commenced to fall out and sank. If we
allow for the fruits floating in fragments a few days longer, it is prob-
able that a month would represent the limit of the floating capacity.
One such fragment I found washed up on the beach of Grand Turk.
However, the hard fruits could only be torn off from the plant during
hurricanes. The mature soft fruit, if it did not sink at once, would
break up afloat in a few days. The plant seems to be quite useless,
and could owe but little directly to human agency in its dispersal.
However, the present islanders carry the living iguanas from island
to island for purposes of food, a practice probably followed by the
Caribs, and any of the hard seeds in the stomachs of these reptiles
would thus be distributed.

Grias cauliflora (Anchovy Pear tree)

Known as the Anchovy Pear tree, Grias cauliflora is one of the
most picturesque trees in the river scenery of Jamaica; and from
many points of view it is amongst the most interesting, its " cauli-
flory " at once attracting attention. The genus was originally
established by Linnaeus from this Jamaican tree, as first described
under its popular name by Sloane in his book on the natural history
of that island (Vol. II., p. 123, etc. ; table 216). Unfortunately Miers,
when he wrote his monograph on the Lecythidacece (Trans. Linn.
Soc, XXX., 1875), to which the genus belongs, was not acquainted
with the fruit. Yet the fruit, as will be shown, plays an important
part in the distribution of Grias cauliflora along the same river
system.

In Jamaica it grows, as Sloane observes, by the riverside. It may
be noticed both on the banks and in the shallows and even on the
slopes of waterfalls. As observed by me, it thrives on the banks of
the Black River and of the Cabarita River above the mangroves
and on the sides of streams in the district south-east of Negril, as
well as in similar stations on the north side of the island. At the
Roaring River Falls it grows not only at the brink of the falls, but
in the wash below them, as well as half-way down their face, where
the fruits have caught in the crevices of the calcareous tufa en-
crusting the declivities. Harshberger (p. 678), when in this locality,
noted that the trees grew directly in the water, their seeds having
germinated in the tufa. It may here be remarked that Sloane's
statement that the Spaniards used to eat the pickled fruits as a
substitute for mangoes may perhaps supply an explanation of the
popular name of the tree. The mature fruits would be singularly
unfitted for food, and doubtless the young fruits were thus employed.

Grisebach gives Jamaica as its only habitat in the West Indies,
and mentions no other West Indian species. I have not been able

212 PLANTS, SEEDS, AND CURRENTS

to find a reference to it in any other island, though Sloane states that
it grows all over the West Indies. From the fact that the fruits,
which possess considerable floating powers, are significantly absent
from the drift heaped up on the beaches of the Turks Islands, it
would seem that the tree does not grow in the islands which are
the source of much of this drift, namely, San Domingo, Porto Rico,
and the neighbouring Leeward Islands. Whilst the fruits are
characteristic of the drift of the Jamaican beaches, being thrown
back on the coast after being brought down by the rivers, as in the
vicinity of the mouths of the Black River, the Cabarita, and the
White River, they did not come under my notice in the beach-drift
of Grenada, Tobago, and Trinidad. They would, therefore, appear
to be unrepresented in the drift of the Orinoco and the Amazon,
since it is stranded in quantity on those islands ; and one may note in
passing that Hart does not mention the tree in his " Herbarium List "
of the Trinidad flora. It is, however, shown below that the same tree
evidently exists on the upper reaches of the Guayas River in Ecuador,
and that an unidentified species of the genus grows in quantities near
rivers on the lower eastern slopes of the Ecuadorian Andes.

Whilst its limited distribution in the West Indies may be partly
due to the little power of preserving the germinative capacity of the
seed in the floating fruit, a matter discussed below, it is evident that
questions quite apart from those relating to means of dispersal are
here raised. According to the Index Kewensis (up to 1905) the genus
holds four species referred respectively to Peru, Panama, the West
Indies, and Guiana. But a mere list of species with their habitats
conveys no notion of the role plants of this genus play in tropical
South America. It would appear that these trees are especially
at home on the lower slopes of the Equatorial Andes on the Pacific
and Atlantic sides, as well as along the upper reaches of the rivers in
that region. Spruce found Grias trees in the Chimborazo forests
extending up to 3500 feet above the sea (Notes of a Botanist on the
Amazon and Andes, II., 286 ; 1908). Mr. A. R. WaUace, who edited
Spruce's book nearly half a century after the traveller returned from
South America, subsequently sent to the Kew Bulletin (1909, p. 216)
some additional notes made by Spruce on the riverside vegetation
of the Upper Amazon. We there learn that a species of Grias almost
entirely composed the forest in places on the Pastasa River, a tribu-
tary of the Maranon branch of the Amazon, on the lower eastern slopes
of the Ecuadorian Andes. The specific identity was not determined
in these cases ; but I may add that on comparing some of my Jamaican
specimens of the fruit of Grias cauliflora with fruits gathered by me
some years before from the floating drift of the Guayaquil River in
Ecuador, the two kinds could not be distinguished from each other.
These floating fruits formed a feature in the drift of this Ecuadorian
estuary, and evidently were derived from the upper reaches of the
river. Specimens of them sent by me to the Kew Museum have been
labelled Grias cauliflora by those in charge.

Looking at the foregoing facts of distribution, it seems fair to
assume that this genus was once far more widely spread over the
West Indies than it is at present. It is doubtless a remnant of a

MISCELLANEOUS PLANTS

213

flora that once held the region, now occupied by the Caribbean Sea,
which united the Greater Antilles with Central and South America
{vide Harshberger, p. 307). From the data given below with respect
to the fruits of Grias cauliflora, it would seem that the genus is quite
unsuited for dispersal by marine currents.

The fruits readily get into the floating drift of rivers, on the banks
of which the tree so often finds its station. They are elliptical,
3 to 3 J inches long, possess eight prominent ribs, and contain a fleshy
though tough seed, IJ to 2 inches in length, which is merely, as in
Barringtonia, sl gigantic hypocotyl, the cotyledons being absent or
inconspicuous. The buoyancy of the fruit is entirely due to the
husky fibro-ligneous pericarp and to its air-bearing tissue, the seed
sinking in water. But though the fruit can evidently float for
months, it is far from impervious to water. It soon loses in the
floating river-drift the outer thin skin of the living fruit, and water
enters freely into the seed-cavity, the membranes investing the seed
affording little or no protection. As a result, the floating fruits
soon begin to germinate in river-drift. Thus, in one of my ascents
of the Black River in January, I estimated that 50 per cent, of the
floating fruits were germinating, showing roots up to three inches in
length. Forty per cent, had been so long in the water that the seed
had disappeared through decay or was in a decaying condition, and
there can be little doubt that most of these had originally germinated.
Ten per cent, had more or less fresh seeds that had not yet begun to
sprout. When the floating fruit reaches the coast, the sea-water
kills the seed, whether or not in the germinating state.

Although when stranded on a sea-coast these buoyant fruits would
either be empty or would carry a dead or decaying seed, it cannot
be doubted that if the trees were at all frequent on the large island
of Hispaniola, about 100 miles away, their fruits would be washed
up on the beaches of the Turks Islands. Their absence from the
drift of these islands indicates the absence or rarity of the tree on
Hispaniola, as well as on Porto Rico and in the neighbouring Lesser
Antilles, islands which collectively represent the main source of the
foreign beach-drift of the Turks Islands. This implication goes to
support the view that Grias cauliflora occupies a very restricted area
in the West Indies, an area which it has been unable to extend
through the agency of the currents. The species would thus appear
to be on the road to extinction in the West Indian region.

Yet the fruits, useless as they are for the purposes of oversea
distribution, are frequent on the beaches for several miles east and
west of the Black River estuary in Jamaica. They are also to be
found amongst the shore-drift near estuaries on other parts of the
coast of this island, wherever the tree thrives at the riverside.
Thus, they were noticed near the mouth of the Cabarita River at
the south-west corner of the island and near the estuary of the White
River on the north side. As they lie on the beaches several still show
the protruding rootlets of the germinating seed, but in a shrivelled
state. Several also are empty, or display a seed far decayed.

But when, as not infrequently happens, the seed is still entire, it
undergoes a very curious change as it lies within the fruit on the

214 PLANTS, SEEDS, AND CURRENTS

beach fully exposed to the sun and weather. The tough, fleshy-
seed of the living fruit here dries up and hardens until it has the
consistence and appearance of a stone, a change affecting both the
seed that has germinated and the seed that has not. In this new
state, however, the seed retains the normal amount of hygroscopic
water, such as we would look for in dead vegetable substances of the
same nature. As is pointed out in my book on Seeds and Fruits
(p. 232), it loses about 12 per cent, of water when exposed to a tem-
perature of 100° C, and there is no indication of its having assumed
the characters of inorganic substances.

On some beaches most of the stranded fruits contained these hard,
stone-like seeds. Thus, on a beach in the Black River district about
25 per cent, possessed either no seeds or seeds far advanced in decay,
the rest having dead seeds that had experienced the stony induration
above described. Placed in a collection of fossil fruits from some
clay formation, one of these oblong, indurated seeds of Grias cauliflora
might pass as a fossil fruit, particularly when a longitudinal section
had been made so as to expose the central axis in relief. At all events,
they might be readily fossilised in ordinary fresh-water deposits,
and it is quite likely that some puzzling organic forms in the old plant-
beds may be petrified seeds which, as in the Barringtonice and
Lecythidece, are merely greatly enlarged hypocotyls.

Hibiscus elatus, Sw. (Paritium elatum, G. Don) and Hibiscus
TiLiACEus, L. (Paritium tiliaceum, A. Juss.)

At some future time I may publish my notes on the different
species of the Hihiscece from the distribution standpoint, a subject
already partially dealt with in my work on Plant Dispersal. Here
I will endeavour to bring my methods to bear on the elucidation
of the causes of the great difference in range between these two
allied species, one (H. elatus) confined to a relatively small area in
the New World, the other (H. tiliaceus) occurring all around the
tropical zone. Hibiscus tiliaceus is a species with which I have
long been familiar in many parts of its range — on the Atlantic and
Pacific sides of America, in various Pacific islands, in the Malayan
region, and in the Keeling Islands in the Indian Ocean.

On making the acquaintance of Hibiscus elatus in Jamaica I recog-
nised that it gave me an opportunity of comparing two allied species
(both of them placed under Paritium) of widely different ranges, and
I asked myself whether this great contrast in range could be asso-
ciated with differences in behaviour, as regards station, means of
dispersal, etc., or whether, assuming the intervention of man, it was
connected with the utility of one tree and the uselessness of the
other. Obviously here was an opportunity of making a flank attack
on the problems concerned with //. tiliaceus. It soon appeared,
however, that the determining factor was concerned neither with
man nor with means of dispersal, but with differences of station, and
that the same point was raised, to which my attention had been
drawn in various genera in the Pacific islands, namely, that in a genus
possessing littoral and inland species, the first had often very wide

MISCELLANEOUS PLANTS

215

ranges and the second very restricted ones (Plant Dispersal, Chaps.
XIV., XV.).

In Jamaica, like H. tiliaceus its sister species, //. elatus is known
as the Mahoe; but although when of small size it might easily be
taken for the other species without close inspection, it is typically
a much more imposing tree. Whilst that of H. tiliaceus is usually
from ten to fifteen feet in height, that of H. elatus is large and spread-
ing and often between thirty and forty feet high. It is also dis-
tinguished by its larger flowers, its hairy seeds, and by its deciduous
involucel and calyx, the loss of which gives the fruits a very
characteristic appearance on the tree. Its distribution in the West
Indies is evidently restricted, Grisebach giving only Jamaica and
Cuba.

But its station is of peculiar interest, since in the comparison of
the two species from the standpoint of distribution it seems to offer
the only determining difference that one can connect with the great
contrast between the ranges of the two trees. In Cuba its habit
is evidently hygrophilous, since Harshberger quotes Fernow (p. 677)
as including it amongst the characteristic trees of the wet " forests
on the weather slopes of the island, where " the atmosphere is nearly
saturated with moisture." Here it is associated with Calophyllum
calaba, a tall tree common in the mountain forests of the West Indies.
Grisebach merely states that in Jamaica it frequents the lower hills
and plains of the interior districts. I found it growing in young wood
in the Moneague district about a thousand feet above the sea and
within the zone of heavy rainfall. It came under my notice on the
banks of the Black River above Lacovia, where the river traverses
the foot-hills, the slopes being well wooded to the waterside with tall
trees of Cassia, Ficus, etc. It also extends for some distance on the
river border below Lacovia, where the river traverses the Great
Morass, a region of fresh-water swamps, where it accompanies on
the riverside Grias cauliflora, the Anchovy Pear tree.

In Jamaica this is not a tree that finds a station amongst the
strand flora or with the xerophilous plants of the dry coastal plains.
In these respects it differs fundamentally from Hibiscus tiliaceus,
growing as it does under much moister atmospheric conditions in
upland regions and descending along the riverside where the wooded
hill-slopes reach the lowlands. It is probable that 'the station at
the riverside is connected with the buoyancy in sea-water of the
seeds, a principle enunciated in my previous work. The seeds, as I
found, are able to float unharmed for at least several weeks, though
their floating capacity is probably less than that of the seeds of
tiliaceus, where my experiments, as well as those of Schimper
(Ind. Mai. Strand Flora, p. 165), indicate a floating capacity of from
four to six months and more.

Hibiscus elatus yields the celebrated Cuba bast, and is cultivated
for that commodity. In this respect it offers another point of resem-
blance to H. tiliaceus, which in its bast was one of the most useful
trees for the Pacific islander, supplying the materials for cordage,
nets, native cloth, etc. Since both possess seeds that could be
dispersed by currents, and since both would be regarded as useful

216 PLANTS, SEEDS, AND CURRENTS

trees, it would not appear that either man or the currents would of
themselves alone determine the great difference in range. I have
shown in my previous work that capacity for dispersal by currents
is not of itself sufficient to give a plant a wide range. Behind this
capacity must lie a littoral station, and behind that again a xerophilous
habit. Whilst H. tiliaceus is to be placed with the xerophytes of
the sea border and of the dry inland plains, H. elatus associates with
the hygrophytes of the wet woods of the interior. Though both
may be found at the riverside, the first is confined to estuaries
within tidal influence, whilst the last frequents the higher reaches
where the river traverses wooded districts and where mixture with
salt water would not be expected to occur.

These two allied species further illustrate the principle, already
alluded to, that whilst coast plants are often spread over a wide area
of the globe, inland plants of the same genus are restricted to a
limited region. Mere capacity for dispersal by currents would not
bring this about unless it concurred with a littoral station. The
seeds of Hibiscus elatus, after being carried down by a river from
the interior of an island to the sea, would find no suitable station
when stranded by the currents on some neighbouring coast. It is
the station at the coast that enables the seeds of H. tiliaceus to
establish the plant when transported to another shore.

I come now to deal more especially with Hibiscus tiliaceus. This
is one of the " problem " plants of distribution, which, like Acacia
farnesiana, Thespesia populnea, etc., are found all round the tropics
and are as a rule littoral in station. With this tree, as with Thespesia
populnea, it is the littoral station that determines the effectiveness
of the currents in dispersing the seeds. But other agencies of dispersal
cannot be excluded, such as the influence of man, and, for local dis-
tribution, the intervention of birds and other animals. Many details
of its station, distribution, and dispersal in the Pacific are given
in my book on Plant Dispersal. Here I will mainly confine my
remarks to its behaviour in the West Indies.

This was one of the plants in which De Candolle took special
interest. In his work on geographical botany (p. 769), whilst recog-
nising man's agency in its dispersal, he suspects that currents were
originally effective agents in its distribution, and perhaps at a very
ancient date. Not knowing whether it was most common in the
east or in the west, that is, in the tropics of the Indian Archipelago
or in those of America, he does not at first assign it a home in either
hemisphere. However, in a later page (p. 792) he places it with
Acacia farnesiana amongst plants spread by the currents, but prob-
ably American and naturalised in Asia and Africa. I scarcely think
that a purely American origin can be sustained. It doubtless attained
its present distribution ages ago, and may have witnessed the emerg-
ence of primeval man around the tropics of the globe. Under such
circumstances speculations as to its home seem futile.

Though found in coast regions in all tropical latitudes, on both
sides of the American and African continents, in Indo-Malaya, in
Australia, and Polynesia, it seems to be less frequent in the New
World ; but this is a matter that requires further investigation. It is

MISCELLANEOUS PLANTS

217

distributed over the West Indian region, extending into subtropical
latitudes on the Atlantic coasts of both North and South America.
It grows on both sides of Central America, exists in the Galapagos
Islands, and was observed by both Baron von Eggers and myself on
the seashore and on the banks of estuaries in Ecuador. It was not
observed by me in the Turks Islands, and apparently forms no feature
either of the Bahamian or of the Bermudian flora. The plants in
the Bermudas are stated to have been raised from seed washed
ashore by the currents about three-quarters of a centurv ago (Chall.
Bot., II., 128a).

In Ecuador and in the West Indies it presented to me the same
variety of stations at or near the coast that it displayed in the Pacific
islands. Wherever it grows, it is as much at home on the borders
of mangrove swamps and on the banks of estuaries as it is among
the trees lining the beach.

It is impossible to deal here with most of the points raised by the
consideration of Hibiscus tiliaceus in the New World, a subject to be
discussed at some future time. But here I may say that both in the
Pacific islands and in the West Indies, as well as in Ecuador, there
always seemed to me to be something refractory about its behaviour
under the test of experiment and observation. The frequent diffi-
culty in obtaining sound seeds, the difficulty in procuring their
germination after prolonged flotation in sea-water, the variety of
station, the inability to discover whether natives ever really did
aid in the spread of the tree, its capacity for vegetative reproduction,
the uncertainty about the agency of birds in its dispersal — these and
other considerations often blocked the way when I was on the eve
of obtaining a clear issue on some point connected with its distribution.

Ipom(ea carnosa, R. Br.

This is an exceedingly interesting beach plant which, according to
some authorities, is found over the warm regions of the globe, whilst
others would limit its distribution chiefly to the New World with
a representation in the Mediterranean and in a few island groups like
the Hawaiian Islands and the Azores. When its synonym is freed
from confusion, it is highly probable that in its range it will be found
to rival the well-known shore species, Ipomoea pes-caprce, with which
it is not infrequently associated on tropical beaches, though very
far behind it in its frequency. Following Urban and Millspaugh,
etc., who have most recently dealt with the plant, the following are
amongst its numerous sjoionyms : Batatas acetoscefolia (Choisy),
B. littoralis (Choisy), Convolvulus acetoscefolius (Vahl), C. littoralis
(L. Syst.), C. repens (Sw.), Ipomoea acetoscefolia (R. and S.), /. arenaria
(R. and S.), and 7. carnosa (R. Br.). It has been confused with Con-
volvulus soldanella^ which may explain how that species has been
sometimes accredited to the tropics of the Old World. It has not
always been separated from Ipomoea pes-caprce, since Seemann
includes /. carnosa (R. Br.) amongst its synonyms.

Even the more limited conception of its distribution suggests
that a plant which could reach islands in the middle of the Atlantic

218 PLANTS, SEEDS, AND CURRENTS

and Pacific Oceans might do a great deal more. Though, as is
observed below, it is tenacious of locality, there are evidently some
deterrent influences which restrict its dispersal, influences, however,
that are not concerned with unfitness for dispersal by currents, since
my experiments show that in their ability to float unharmed for
many months in the sea its seeds are not inferior to those of Ipomcea
pes-caprce, one of the most typical beach plants of the tropics.

Let us look at some of the features of its distribution. In North
America, according to the data supplied by Harshberger, it grows
on the shores of the Mississippi delta, on the Louisiana beaches in
association with Ipomoea pes-caprce, and around the coast lagoons
near La Paz in Lower California. In the West Indies, as we learn
from Grisebach, Hart, Millspaugh, and others, it grows on the
beaches of Jamaica, the Cayman Islands, Porto Rico, and Trinidad ;
and it has long been known from the Guianas and Brazil. It is also
a Mediterranean plant, and it has been found also in the Azores
as well as in the Hawaiian Islands in the centre of the Pacific.

Until recently it was only known from one locality in the Azores,
namely, Porto Pym in Fayal, where it was observed by Watson in
1842, by Brown in 1894, and by myself in 1913 and 1914. However,
during my stay on Pico I found it thriving on a beach just south
of Magdalena at the western end of the island. In Hillebrand's
Flora of the Hawaiian Islands it is only recorded from Niihau, an
island at the extreme north-west of the group, where it was collected
by Remy half a century or more ago.

Its behaviour in the Cayman Islands is characteristic. Mr. Savage
English in his account of Grand Cayman (Kew Bulletin^ No. 10, 1913)
refers to a small colony which had established itself on the shore
in one locality, presumably after the hurricane of 1903, adding that
it was new to the islanders. However, Dr. Millspaugh, who visited
the Cayman Islands in February 1899, found it on the beach at Spot
Bay in Grand Cayman, as well as on Cayman Brae (Plant. Utow., I.,
85). The plant is evidently tenacious of locality, since it still grows
in the Azores in the same locality where it was first noticed more
than seventy years ago. Unlike its companion beach plant, Ipomoea
pes-caprce, its stem is mostly buried in the sand, only the leaved
and flowering shoots usually showing, a feature described in detail
by Dr. Millspaugh. When I visited Porto Pym on March 12, 1913,
only a few young leaf-shoots were showing above the sand. A month
later they were much more numerous. On July 21, 1914, it was
flowering abundantly and in early fruit; whilst numbers of the
previous year's seeds bared of their hairy covering lay on the sand.
On August 12 many of the capsules had matured and were opening,
displaying their hairy seeds.

To test their buoyancy, a number of the hairy seeds of the same
year and of the bared seeds of the previous year were put in sea- water
a few weeks after collection. After three months 20 per cent, of
the hairy seeds and all of the bared seeds remained afloat, and
after seventeen months 10 per cent, of the hairy seeds and 90 per
cent, of the bared seeds were still floating. The survivors germinated
freely, and from them I raised plants. If the currents are responsible

MISCELLANEOUS PLANTS

219

for the existence of this plant in the Azores, the seeds must have come
in the Gulf Stream drift in the company of the other West Indian
seeds thrown up on these islands. It is true that the Mediterranean
shores would offer a much nearer source ; but the current connections
do not allow us to appeal to that region. It is, however, possible,
as implied by Dr. Millspaugh in the case of Cakile edentula, its com-
panion on the beach of Porto Pym, that it may have been introduced
with ballast. But the same suspicion would fall on the other beach
plants of this little bay, Polygonum maritirnum, Salsola kali. Euphorbia
peplis, etc. That West Indian seeds are sometimes stranded there
is indicated by my finding on the same beach a seed of Sapindus
saponaria apparently in a sound condition.

IpOMCEA PES-CAPR.T:, Sw.

Since this wide-ranging tropical beach plant has been discussed
in detail in my book on Plant Dispersal in the Pacific, I will restrict
my remarks mainly to its occurrence in the West Indian region.
The circumstance that it came under my notice in Jamaica, Turks
Islands, St. Croix, Grenada, and Tobago, as well as at Colon, suffi-
ciently illustrates its general distribution over this area. From the
data supplied by Grisebach, Millspaugh, Harshberger, etc., it is
apparent that all the larger islands and most of the smaller ones
possess this species. Excluding the small sand-keys, a few hundred
yards across, I would imagine that this plant has established itself
on every small island where there are beaches. Numbers of beaches
were visited by me on the north, south, and west coasts of Jamaica,
and the species was noticed on nearly all of them. However, certain
restricting influences seem in places to affect its distribution. Thus,
Mr. Lansing found it on only four of the nineteen Florida sand-keys
examined by him, which contrasts with the prevalence there of
such beach plants as Cakile fusiformis. Euphorbia buxifolia, and
Suriana maritima that occur on most or on nearly all of them.

In the West Indies this plant did not present itself to me far away
from the beach, as it did in the dry inland plains of Vanua Levu,
in Fiji, where it attained a maximum height of 1300 feet above the
sea. The other botanists, whose works are at my disposal, say nothing
of its inland extension in this region. In the Turks Islands it usually
grows over the sandy and rocky surfaces of the smaller cays, which
are often only one or two hundred yards across and display sea-
drift thrown up by the breakers in the centre. In Gibb Cay, however,
which is of greater height, the plants had climbed the sandy slopes
to an elevation of nearly fifty feet. On the larger cays they thrive
on the dunes behind the beach; but although the conditions in the
interior of the islands seem very favourable for their inland exten-
sion, I possess no record of their occurrence far from the beach.

As in other parts of the tropics, the seeds are often to be found in
stranded beach-drift; and there can be no doubt that the currents
are effective agents in dispersing the buoyant seeds over these
seas, since a good proportion can float unharmed for six months and
more. They came under my notice on the beaches of Jamaica,

220 PLANTS, SEEDS, AND CURRENTS

Tobago, etc. ; and, as in the Turks Islands and elsewhere, seedlings
that had raised themselves from stranded seeds were observed grow-
ing in the beach-drift.

I have been obliged to omit, on account of the limits of space, a
very long note of many pages on the distribution of this plant in the
warm latitudes of the globe as compared with Convolvulus soldanella,
which takes its place on the beaches of temperate latitudes. As a
rule, Ipomoea pes-caprcB monopolises the coasts between the 30th
parallels of north and south latitude, whilst Convolvulus soldanella
holds the shores of the temperate zones beyond those latitudes in
both the north and south hemispheres, though in the New World
wide gaps may separate the two species. As far as I know at present,
the ranges of the two species only overlap in Australia. It has long
been known from the observations of Cheeseman that the two plants
meet in the neighbouring Kermadec Group (lat. 31° 30' S.), and it
would, therefore, be expected that the two plants would overlap on
the eastern coasts of Australia. Mr. Maiden very kindly looked up
the matter in my interests, and the conclusion he formed was that

the two species overlap in northern New South Wales and in
southern Queensland for at least 300 miles." Looking at the data
which he supplied me it would be fair to conclude that the over-
lapping takes place between the 25th and the 32nd parallels, Ipomoea
pes-caprce reaching south to 32° S. and Convolvulus soldanella extend-
ing north to 25° S. New Zealand, a home of C. soldanella, is well
outside the zone of /. pes-caprce and does not possess it. Prof. Ewart
also supphed me with some valuable information on this point.

The comparison has opened up so many problems of distribution
in different parts of the world that it would take more space than can
be allotted in these pages to deal satisfactorily with the subject.
When I have filled up the numerous lacunce in my research, I hope
to publish it in the form of a paper. A short discussion of the ques-
tion is given in my previous work on Plant Dispersal in Note 49 of the
Appendix.

Ipomcea tuba, Don.

According to the various authorities at my disposal this plant is
confined to the warm latitudes of the New World, where it is widely
distributed, as in South Florida, the Bahamas, the Greater and
Lesser Antilles, reaching south to the Guianas and Brazil. Urban
regards it as almost cosmopolitan in the warm regions of the globe
(Symh. Antill., IV., 513) ; but he seems nearly alone in holding this
view. Though not known from the Bermudas, it was found both
by Moseley and Ridley on the small Fernando Noronha group lying
about 200 miles off Cape St. Roque (ChalL Bot, III., 19 ; Journ. Linn.
Soc. Bot., vol. 27).

Particulars as to its station are often lacking; but it is evidently
as a rule a maritime plant, and in the manuscript of the Bahamian
flora lent to me by Dr. Millspaugh it is described as a denizen of
sandy shores in that archipelago; but I do not gather that it ever
intrudes on the beach after the fashion of Ipomcea pes-caprce. Thus

MISCELLANEOUS PLANTS

221

in the Florida sand-keys it grows with other littoral plants away
from the beach. In the Turks Islands it thrives on both rocky and
sandy slopes behind the beach. Dr. Millspaugh, in his paper on the
Florida sand-keys, refers to its " often high location on many rocky
Antillean islands." In another paper (Plantce JJtowance) he alludes
to it as growing over low bushes on the shores of Cayman Brae.

The same American botanist shows that this plant, which is
referred to under the synonym of Calonyction album (House), grew
always towards the centre of the sandy interior of the low islets
forming the Florida sand-keys, removed alike from the mangrove
border on the lee side and the beach on the weather side. Of
nineteen islets examined, it was only found on four.

It was only observed by me on three of the ten islands of the
Turks Group, but never on the largest islands. On Gibbs Cay it
grew in quantity over the sandy slopes and summit at a height of
thirty to sixty feet above the sea, but not on the beach. On Pear
Cay, where there is but little beach, it occupied much of the rocky
surface, twenty to thirty-five feet above the sea. On Eastern Cay
it did not grow on the extensive low sandy flats bordering the sea,
but on its stony slopes fifty to sixty feet above the sea-level.

The seeds are well suited for dispersal by currents. Of ten placed
in sea- water in the Turks Islands all were afloat after forty-five days,
the kernels being sound and quite dry. In a later experiment in
England on seeds that had been gathered for fifteen months, 90 per
cent, remained afloat after ten weeks, and from their condition they
would evidently have floated unharmed for a considerably longer
period.

Laguncularia racemosa, G.

This West African mangrove tree, which finds its most character-
istic station, with Avicennia nitida, on the landward side of the
mangrove swamp, is generally distributed in the West Indies, and
has accompanied the other two mangroves, Rhizophora mangle and
Avicennia nitida, in their extension to the Bermudas. It grows on
the Atlantic side of the American mainland from Florida by way of
Mexico and Venezuela to Rio de Janeiro (Schimper, p. 66), and also
on the Pacific side on the Panama, Ecuadorian and Lower Californian
coasts (Harshberger).

The tree is dealt with in my book on Plant Dispersal, and here I
will chiefly endeavour to supplement those remarks. It will be
unnecessary to name the localities in which I noticed it, since it came
under my notice wherever I examined the mangrove formation, as
in Jamaica, Turks Islands, St. Croix, Grenada, Tobago, Trinidad,
Colon, and Panama. According to Millspaugh it grows on ten of the
fourteen Florida sand-keys that support mangroves, and is evidently
one of the first plants to stock the emerging islet.

Laguncularia racemosa is as a rule merely semi- viviparous. Only
in rare instances does one find the radicle protruding from the fruit
on the tree. Generally the dark green embryo does not effect more
on the plant than the rupture of the thin seed-coats, the protrusion
of the hypocotyl taking place shortly after the fruit has dropped

222 PLANTS, SEEDS, AND CURRENTS

from the plant, either on the mud or in the water. The enormous
number of seedhngs, only three or four inches high, that are at
times to be noticed under the trees affords evidence of this partial
vivipary. They are sometimes crowded together in thousands so as
to almost form a turf, and the waste must be tremendous. Should
the buoyant fruits drop into the water, whether into a river or into
the sea, they quickly proceed with the germinating process, and can
be carried in this condition for a great distance. Germinating fruits
of Lagimcularia are frequent in the floating drift of the estuary of
the Guayaquil River in Ecuador, and I noticed them in a healthy
state twenty miles out at sea with the protruding hypocotyl be-
tween 3 and 12 mm. in length. In another locality, about three
miles off the coast of Ecuador, I estimated that 90 per cent, of the
floating Laguncularia fruits were germinating. The stranded fruits
of L. racemosa were frequently found by me on the beaches of
Jamaica, Tobago, Trinidad, etc., and they were nearly all germinating.

The capacity of proceeding with the germinating process in sea-
water has been already implied, and fruits in this condition can be
transported far by the currents, more especially since fish do not
nibble at the protruding seedling. It is not likely that any floating
fruits could remain for more than a week or two in the sea without
showing the radicle; and it is quite possible that the germinating
fruits would survive the passage of two and a half or three months
in the Equatorial Current from the West Coast of Africa to the shores
of Brazil. That the New World derived its species of Laguncularia
from the West Coast of Africa before the emergence of the Panama
Isthmus seems probable.

The fruits can withstand drying when detached from the tree in
the entire condition. Five green non-germinating fruits were placed
in sea-water in Jamaica after being allowed to dry in the air for
nearly two weeks. A fortnight afterwards three were germinating
healthily afloat.

Comparison of the Shape and Dimensions op the Fruits op Laguncularia
racemosa of the West Indian Region and of the Panama Isthmus with
THOSE of the Laguncularia of the Estuary op the Guayaquil River and

OF THE neighbouring COASTS OF ECUADOR.

Form, etc.

Length

Breadth

Laguncularia racemosa
of the West Indies, etc.

Broadens out into
shoulders near the top.
Ribs and wings more promi-
nent.

17 mm.

8 to 9 mm.

Laguncularia of Ecua-
dor.

Becomes narrower near
the top. Ribs and wings
less prominent.

18 to 19 mm.

6 to 7 mm.

In my book on Plant Dispersal (p. 498) reference is made to the
circumstance that the Laguncularia tree of the Guayaquil estuary
and of the neighbouring coast swamps of Ecuador has a fruit differ-

MISCELLANEOUS PLANTS

223

ing somewhat in form from that of the Laguncularia (L. racemosa)
found on both coasts of the Panama Isthmus, and, I may here add,
in the West Indies generally. Whether the difference is specific is
doubtful. The fruit of the Ecuadorian tree is more symmetrical,
longer and narrower, and does not broaden out into two shoulders
near the top as in the case of the typical L. racemosa.

LiMNANTHEMUM IIUMBOLDTIANUM, Gr.

This aquatic plant is distributed over the warm regions of the
American mainland and in the West Indies. As observed in Jamaica
it was equally at home on the exposed muddy borders of ponds and
in the water. The moist seeds are globose, hairless, smooth, and
1-5 mm. in diameter. In the wet state about sixty-three seeds go to
a grain ; but in the dry state at least double that number would be
required to make up that weight. On account of their oily surface
the seeds float on the surface of a pond by throwing off the water,
but when completely submerged they sink. They would thus be
able to float for a long time in dry weather, and this would aid their
early germination; but the raindrops would soon sink them. The
seeds of our English species behave in a similar way, but here the
flotation is assisted by a marginal fringe of hairs. These seeds are
oval, flat, 4 to 5 mm. long, and have an oily surface, which
enables them to repel the water ; but they can be sunk by dropping
water on them. I observed the germinating process in both the
English and West Indian species. Germination usually takes place
in the case of sunken seeds, since from one cause or another the
floating seed would soon be sent to the bottom in a pond. After
the process is well advanced the seedling floats up and continues its
growth at the surface.

The general subject of the distribution of the genus is discussed
in my work on Plant Dispersal. I have been familiar with these
plants in England, Fiji, and Jamaica, and have formed the conclusion
that in the tropics aboriginal man has often unintentionally assisted
in their dispersal. He cultivates many of his edible tubers (Colocasia,
Alocasia, etc.) at the borders of ponds and ditches where Limnan-
themums thrive.

LUFFA ACUTANGULA, Roxb,

This is an introduced Asiatic species to which I refer here merely
in connection with the slight floating power of its seeds. The seeds,
as tested in the well-dried condition in Jamaica, sink in a day or two.
Seeds of another cultivated introduced species were experimented
on in Fiji, and found to sink after a few days in sea- water. The
interest of these results lies in the circumstance that the seed of
Lujfa insularum, A. Gray (a maritime form of L. cylindrica), which
grows in the Pacific islands on the shore and in the plains behind,
are able to float in sea-water unharmed for months, and are doubt-
less often dispersed by currents. This subject is dealt with on p. 426
of my book on Plant Dispersal. This bears on the question of the
connection between seed-buoyancy and a littoral station.

224 PLANTS, SEEDS, AND CURRENTS

The Turk's-head Cactus (Melocactus communis) of Turks

Islands

This plant, which figures on the farthing stamps issued in recent
years for this colony, has a fancied resemblance to a man wearing a
fez, and has given its popular name to the islands. It is still abundant
on Eastern Cay and Cotton Cay, and, though now infrequent, was
originally common on Grand Turk. The Rev. J. H. Pusey, for
many years a Baptist minister in these islands, says in his handbook
{Jamaica, 1897) that it lasts a great number of years without the
support of any earth whatever." Small specimens brought by me
to England proved their capacity of surviving several weeks in a
packing-case. At present there is a risk of this interesting plant
being exterminated. I met a planter from the Caicos Islands in
1911 who was taking several cases of them to the United States to
test the market for their sale. This cactus is usually designated in
general literature as Melocactus communis, DC, a species found
also in Jamaica, Haiti, Antigua, etc. But in Britton's and Mill-
spaugh's manuscript of the Bahamian flora it was regarded under
the name of Cactus bahamensis as a plant restricted to the southern
Bahamas (the Inaguas, Turks Islands, Caicos Islands, etc.).

The small red juicy fruits, about 16 mm. long, contain minute
black seeds rather over a millimetre in length, and well suited for
dispersal by frugivorous birds. Another smaller cactus of similar
habit of growth, which I take to be Mamillaria simplex, is associated
with it on Grand Turk. It possesses seeds of the same size. The
seeds of the common Opuntia tuna measure 5 mm. across.

CHAPTER X

MISCELLANEOUS PLANTS (continued)

MORINDA ROYOC, L.

According to the data supplied by Grisebach, Hemsley, and
Millspaugh this plant has a wide distribution in the warm regions of
the New World, principally at or near the coast, or, as Hemsley
puts it, " usually growing in maritime districts " (Chall. Bot., II., 38).
The following are the insular and continental localities given : Ber-
mudas, Florida, Bahamas, Cuba, Isle of Pines, Cayman Islands,
Jamaica, Haiti, Honduras, and Panama.

I was only familiar with it in Jamaica, where it was noticed in
different localities near the beach on the north coast. Grisebach
states that it was found by all collectors along the sea-coast of that
island. But here it may also grow inland. Thus it was observed
by me at the roadside a mile or two at the back of St. Anne's, and
600 or 700 feet above the sea. In South Florida, according to
Harshberger, it is an inland plant of the " banana holes " and of the
"hammocks" (Trans. Wagner Inst., Oct. 1914). Millspaugh says
that it occupies scrublands and pine-barrens in the Bahamas {Prcenunc.
Baham.), and doubtless it often grows a considerable distance from
the coast. According to the same botanist, it is known as " rhubarb "
in the Caymans and in the Bahamas. In the first-named islands it
is employed medicinally in the place of that drug, and it furnishes a
yellow dye. In its use as a dye plant it resembles Morinda citrifolia
in the Old World, which has long served this purpose in the East.

Its usual maritime station also links it with Morinda citrifolia,
but there are other important similarities from the standpoint of
dispersal. The Asiatic plant and the genus as a whole are dealt
with from this point of view in my work on Plant Dispersal. It is
there remarked that though the fruit of M. citrifolia soon decays
when afloat, the woody, hard pyrenes possess great buoyancy, which
they owe to a large bladder-like cavity, probably, according to
Schimper, a modified seed-chamber. Though the pyrenes of M.
royoc are smaller, they have the same characters and behave in the
same way, their great floating capacity being connected with pre-
cisely the same structure. Some of them which I placed in sea-
water were all afloat and sound after five weeks, and gave promise
of floating unharmed for many months. It is probably to this
floating capacity of the pyrenes that the species owes its station at
the sea-coast; and in this respect it is to be placed in the same
Q 225

226 PLANTS, SEEDS, AND CURRENTS

category as M. citrifolia, the pyrenes of which are often dispersed by
currents.

It is shown in my previous work that the fleshy fruits of this
genus must often attract birds, and that the pyrenes could be readily
transported by frugivorous birds across tracts of ocean. Nearly all
of the fifty known species are inland plants ; and the indications are
that only the littoral plants possess buoyant pyrenes, the bladder-
like cavity being either absent or but slightly developed in the
pyrenes of inland species. From its range over the warm regions of
the globe Morinda is a very interesting genus for the student of
distribution. Very noteworthy is it that quite 60 per cent, of the
species are confined to islands, large and small, in Malaya and in the
Indian and Pacific Oceans.

Though this is predominantly an Old World genus, not more than
15 per cent, of the species being restricted to America, the peculiar
New World species have originated in several localities, as in Mexico,
Guatemala, Yucatan, Panama, Venezuela, Haiti, and Cuba. Nearly
all these localities are given in the Index Kewensis. Urban has
described a new species from Haiti under the name of M. buchii
(Symb. AntilL, I., 481) ; and Dr. Greenman has in recent years dis-
tinguished a new species, M. yucatanensis, which had been previously
referred to M. royoc. It is found in brushlands and forests in the
interior of Yucatan (Publication 126, Botanical Series of the Field
Columbian Museum, Chicago, 1907). Nothing, however, is said of
the distinctive structure of the pyrenes. The plant is known in
Yucatan under the Mayan name of " Joyoc (Hoyoc). If, as seems
probable, this is a plant of the Royoc series, then we might here be
presented with the case of a derivation of an inland species from a
littoral species, a subject generally discussed in my book on Plant
Dispersal.

As regards the history of the American representatives of Morinda^
I venture to hold, in spite of the numerical superiority of the genus
in the Old World, that, like many other genera common to the
western and eastern hemispheres, it originally spread from a common
centre in high northern latitudes during one of the warm geological
periods in those regions.

Omphalea triandra, L.

This tree, the " cobnut " of Jamaica, is interesting from the stand-
point of dispersal by currents, since its seeds float buoyantly and
occur occasionally in the drift on Jamaican beaches. The tree
grows in hills behind St. Anne's in that island, and it was in this
neighbourhood that I found the seeds on the iDeaches. The seeds
are globose, about an inch in size, brown-coloured, and not unlike
chestnuts in look. The buoyancy arises from a large internal cavity
and also from the independent floating power of the kernel, portions
of the albumen floating in water. The brown covering is seemingly
waterproof, and no doubt the seeds would float for some time. It
is, however, very doubtful whether they could find their way to a
suitable inland station when stranded on a coast. Since the seeds

MISCELLANEOUS PLANTS

227

of Omphalea diaiidra owe their floatiiifr power to the same causes,
it is probable that this type of buoyaney is characteristie of the
^enus (sec p. 159). According to Grisebach and Pax {Pflanzenreich,
IV., 147, v.), Omphalea triandra has been found in Jamaica, Haiti,
and the Guianas.

SciEVOLA Plumieri (Vahl) and Sc. Kcenigii (Vahl)

One of the most characteristic of the littoral plants of the West
Indies is Scawola Plumieri, It is especially interesting from the
standpoint of distribution, since, as in the case of other genera
represented by littoral plants in this region, such as Rhizophora
(p. 141), Tournefortia (p. 247), and Carapa (p. 141), it divides- with a
sister species the tropical shores of the world. In this case, however,
there has been unfortunately some confusion between the two
species, Sccevola Plumieri of the beaches of tropical America and
tropical Africa, and Sc. Koenigii of the beaches of tropical Asia, Aus-
tralia, and Polynesia, a subject discussed in Note 5 of the Appendix.
But the matter has been cleared up by Krause in his recent mono-
graph on the GoodeniacecB {Das Pflanzenreich, IV., 277; 1912). The
confusion in the synonymy quite obscured the issues raised in the
matter of their areas of distribution. Now, as far as littoral plants
are concerned, Sccevola comes into line with the other three genera
above referred to. It puts much the same questions and raises
much the same issues ; yet the differences that occur are in themselves
full of suggestion for the future investigator.

These two species, as I have said, occupy between them the
beaches of the warm regions of the globe, both insular and conti-
nental. As limited by Krause on pp. 18, 120, 121 of his memoir,
Sccevola Plumieri occupies the shores of the West Indian islands
and the eastern coasts of the American mainland from Florida by
way of the Bay of Honduras to the shores of Brazil, reaching as far
south as Rio de Janeiro. It extends northward to Bermuda. He
does not give any station on the Pacific coast of America; but
Grisebach and Hemsley record it from the Galapagos Islands (Flora
Brit. West Ind.; Chall. Bot., IV., 161); and according to Baron von
Eggers it is one of the " West Indian strand plants " that make up
the " sand-flora " of the coasts of Ecuador (Deutsche Geogr. Blatter,
heft 4, band 17, Bremen, 1894). Harshberger also gives La Paz
(lat. 24° N.) on the coast of Lower California as a habitat (Phytogr.
Surv. N. America, p. 639). Krause does not give many localities
for the West Indian side of Central America; but the Caribbean
shores of Mexico may here be mentioned as indicated by Britton
and Millspaugh in the manuscript of their Flora of the Bahamas,
and the last named speciall}^ records it for the shores of Yucatan,
near Progreso (Plantce Utowance, pt. I.). It is also implied by
Grisebach as existing on the Caribbean coasts.

According to Krause, Sccevola Plumieri ranges along the West
African coast from Senegal to Benguela, or through nearly thirty
degrees of latitude (16° N. lat. to 13° S. lat), and along the whole
coast of East Africa from Somaliland to the Cape. Further east-

228 PLANTS, SEEDS, AND CURRENTS

ward it intrudes into the area of Sccevola Koenigii, attaining its limits
in this direction in Southern India, Ceylon, and Mauritius; and at
times both species are recorded from the same limited area, as in
Mauritius.

Generally speaking, the domain of Sccevola Koenigii begins where
that of Sc. Plumieri ends. It is not recorded either from the Pacific
side of America, or from the East Coast of Africa, which in a general
sense represent the limits of the area appropriated by its sister species.
But between those continental coasts it ranges through the tropical
zone, and sometimes extends beyond. Thus we find it on the
beaches of the Pacific islands from Rarotonga to Hawaii and from
New Caledonia to Liu-Kiu, in the northern part of Australia, in
New Guinea and throughout Malaya, in South-eastern Asia, and in
the islands of the Indian Ocean. It finally reaches its westward
limits on the Malabar coast, in the Seychelles, and in Madagascar,
but apparently not reaching the East Coast of Africa.

It has already been said that these two interesting species of
Sccevola, in dividing the coasts of the warm regions of the globe
between them, raise the same issues as those presented by Carapa,
Rhizophora, and Tournefortia, where in each case two sister species
similarly divide the world; but there are important differences.
Although one of the two littoral plants of each genus is widely
spread in the New World, it is confined there in the case of Tourne-
fortia. With Carapa and Rhizophora the American shore plant
extends to the African West Coast, but is not found on the east side
of that continent; whilst the American Rhizophora meets the
Asiatic species in the Pacific islands, as in Fiji.

Before going further something may be said of the genus to which
the two littoral species of Sccevola, which are here compared, belong.
Of eighty-three species recognised by Krause, fifty-eight, or 70 per
cent., are confined to the Australian region. The rest are nearly
equally divided between the Malayan region (including New Guinea)
and the Pacific islands, excepting the two shore species with which
we are specially concerned.

Looking at the facts of distribution relating to the Goodeniacece
given in this monograph, one becomes conscious, as regards Sccevola,
that one is dealing with a modification of a geographical type rather
than with a genus as usually understood, since it is pointed out by
Krause (p. 14) that of the thirteen genera in the family ten are confined
to Australia and Tasmania, and that of the total of 291 species only
twenty-seven, or 9 per cent., are found outside this region, the bulk
of the species being restricted to the western half of Australia. It
is of importance to note that of these twenty-seven species all but
two species belong to Sccevola, a very significant indication that
this genus has been especially favoured in its means of dispersal.

Sccevola, therefore, is not only in the main an Australian genus, but
it belongs to a family that is also chiefly Australian. It is a member
of a family that thrives where the physical conditions often deter-
mine the xerophilous habit in plants, and, as I have before observed,
this habit is the first requisite for a littoral station. It is, therefore,
in this connection of special interest to refer to the remark of Krause

MISCELLANEOUS PLANTS

229

(p. 19) that SccBVola as a genus has a characteristic incHnation for a
littoral life (" neigung fiir das Litorallebcn "). This inclination is
well illustrated in the circumstance that many of the Australian
species are equally at home in arid inland districts and at the coast,
though very few are exclusively littoral in their station. The
adoption of a station at the coast does not necessarily involve a
wide range for a plant, the acquirement of buoyant qualities by the
fruit or by the seed being as a rule needed for a wide distribution.
In other words, the littoral plant must be suited for dispersal by
currents to ensure a wide range. Thus it may be safely assumed
that the five other species of Scoevola named by Krause (p. 19) as
the most typical strand plants have but slight capacity for dis-
tribution by currents, since they are all confined to Australia, and
four of them are only known from West Australia. The origin of
buoyancy in seeds is dealt with in detail in my book on Plant
Dispersal, Buoyancy whether of seed or fruit is quite accidental as
far as adaptation to dispersal is concerned. It is just as likely to
be developed in inland plants, especially where dry conditions pre-
vail ; and it is shown that in such cases, where the plants are xero-
phytes, they tend to gather at the coast. But it is only the littoral
station that determines its utility for dispersal, since it brings the
plant with buoyant seeds or fruits within the influence of the currents.

In many strand floras there is an element composed of local
inland xerophilous plants, which, being at home in the neighbouring
dry districts of the interior, encroach' in places on the beach, but
through lack of fitness for dispersal by currents do not accompany
the other beach plants with buoyant seeds or fruits that extend
their ranges across the sea far beyond that particular locality. With
the exception of Scoevola Koenigii, it is probable that nearly all the
Australian species of the genus that find their homes more or less
frequently on the beach belong to this category. The littoral flora
is liable to receive numerous accessions from the inland flora, where
the conditions of the interior favour the growth of xerophilous
plants. This I found to be especially the case in the Turks Islands,
where the plants growing away from the beaches are mostly xero-
phytes. So also on the Chilian beaches I found that the strand flora
contained numerous intruders from the neighbouring dry inland
regions {Plant Dispersal, p. 478). Schimper lays stress on the
inclusion in the Indo-Malayan strand flora (p. 197) of colonists from
sandy or stony places inland. Harshberger tells us how the numerous
xerophytes of the chaparral scrub of the arid interior of Mexico and
Texas descend to the plains that border the sea and extend along the
shores of the Gulf of Mexico (p. 660, etc.).

I have here gone far enough to indicate the nature of the problems
opened up when we recognise in Sccevola a genus eminently suited
for supplying strand species. We are now in a better position to
understand how the genus has come to furnish two of the limited
number of strand plants that are cosmopolitan, or semi-cosmopolitan,
in the warm regions of the globe, a considerable proportion when
we reflect that even including the plants of the mangrove formation
the total number would probably not exceed fifty.

230 PLANTS, SEEDS, AND CURRENTS

Before dealing vnth the means of dispersal of the wide-ranging
littoral species, Sccevola Plumieri and Sc. Koenigii, reference may be
made to the genus in this connection. When in the Pacific the
writer formed the opinion that the inland species, though not fitted
for dispersal by currents, were well suited on account of their fleshy
drupes for dispersal by birds, his observations and experiments
indicating that onty a littoral station was associated, as in the case
of Sc. Koenigii, with the capacity for distribution by currents (Plant
Dispersal, p. 135, etc.). In this way, it was held, the range of such
a shore species was enormously extended as compared with the
inland species, nearly all of which were restricted to a particular
group of islands or were confined to small areas.

Krause (p. 14) deals with the subject; but his inferences were
based entirely on the structural characters of the fruits. He con-
siders that the fruits of Sccevola are adapted for two methods of
dispersal — one by birds and other animals when the fruit has a fleshy
covering and a hard endocarp, the other by currents where the
endocarp has a cork-like outer layer suggestive of buoyancy in the
fruit. In illustration of dispersal by currents he takes four West
Australian species of dune plants growing on and near the coast, as
well as Sccevola Kcenigii, the widely ranging strand plant of the Old
World ; but no results of experiments are given and none are referred
to, since they did not come within the scope of the work. Amongst
examples of dispersal by birds he mentions the strand plant of the
New World and of both the African coasts, Sccevola Plumieri, for
the fruits of which only dispersal by birds seemed possible, the
agency of the currents being excluded. I formed the same opinion
on first examining these fruits in the West Indies, but experiments
showed that they are also well fitted for distribution by the currents.

The two modes of dispersal of the fruits of Sccevola have long been
established by Schimper, myself, and other students of distribution.
They may be combined in the same species, as with the two world-
ranging beach plants Sc. Koenigii and Sc. Plumieri, the juicy exocarp
attracting the bird, and the buoyant stone fitting the fruit for trans-
port by the currents. Schimper first apportioned their true values
to these two capacities in the same species when in the case of Sc.
Koenigii, in his book on the Indo-Malayan strand flora (p. 156), he
regarded the fruits as fitted for dispersal over long distances by the
currents and for short distances by birds. The fruit is specially
described and figured in his work (p. 172).

Yet it is evident from the treatment of Sccevola by Krause in this
monograph that the greater number of the species have dry or hard
fruits that would not be especially attractive for birds. In this
connection it is very significant that the two sections, Sarcocarpcea
and Xerocarpcea, which derive their names respectively from the
fleshy and from the dry character of the fruits, include in the case
of the first named the species that are established in localities farthest
away from the Australian home of the genus, and in the case of the
second named nearly all the species of the genus that are confined
to Australia. The section Sarcocarpcea includes not only the inland
species that have established themselves through the agency of

MISCELLANEOUS PLANTS

231

birds in distant islands of the tropical Pacific, as in Hawaii and Fiji,
but the two world-ranging shore plants, Sccevola Koenigii and Sc.
Plumieri, which owe their wide dispersion mainly to the currents,
but also to some extent to birds. The great increase in the range
due to the capacity for dispersal by currents is well illustrated by
these two strand species of Sccevola, there being but little probability
that other species of the genus possess fruits capable of floating
unharmed for long periods in the sea.

It is not likely that the buoyancy which Krause assumes on
structural grounds for the fruits of four littoral Australian species
of Sccevola can be very marked, since none of them are known from
outside regions and three are confined to West Australia. Yet the
principle involved may be correct, and we may have here reproduced
the behaviour of Terminalia, as described by Schimper in his book
on the Indo-Malayan strand flora (p. 180). In this genus, although
the fruits of several inland species possessed floating powers asso-
ciated with buoyant tissue in their coverings, the fruits with by far
the greatest floating capacity and with the greatest development of
buoyant tissue were those of Terminalia katappa, the only character-
istic shore species and the one most widely spread.

I will now deal more especially with the American and African
shore plant, Sccevola Plumieri, contrasting it as regards its modes of
dispersal with the Asiatic and Pacific littoral species. Sc. Koenigii.
Having been for many years familiar with the Asiatic species, in
Java, Polynesia and the Keeling Islands, I have been at length able
to compare its behaviour with its sister species of the Atlantic
region. This was accomplished in the Turks Islands at the south-
east end of the Bahamas, where I enjoyed abundant opportunities of
studying the plant.

As regards its distribution in the West Indian region the data
show that Sccevola Plumieri is spread over the Bahamas and the
Greater and Lesser Antilles; but apparently it is absent from
Trinidad. It extends north to South Florida and reaches Bermuda.
In the Florida sand-keys it does not seem to be at all frequent, since
Mr. Lansing found it on only four of the nineteen keys examined,
and in only one of them did it exist in any quantity. The shrub, it
may be added, is much less hardy than that of Sc. Koenigii, and it
evidently has greater difficulty in establishing itself on a fresh coast.
It is noteworthy in this respect that in March 1895 Dr. Millspaugh
found only a single individual on the Alacran Shoals {Plantce
Utowance).

In the Turks Islands, where it attains usually a height of from two
to two and a half feet, it is known as the Ink-berry plant, on account
of its black, juicy fruits of the size of a large cherry. Its distribution
in this small group is irregular and varies from year to year, a result
due to the destructive action of hurricanes in the smaller keys or
cays, and to its being much appreciated by cattle and goats in the
larger islands, the whole plant being often devoured. I was informed
by a resident that it thrives only on beaches to which animals cannot
get access. Compared with the more woody plants of the beaches,
such as Tournefortia gnaphalodes and Suriana maritima, these more

232 PLANTS, SEEDS, AND CURRENTS

or less fleshy shrubs cannot withstand the hurricanes and gales.
They are not able, as in the cases of the two plants just named, to
maintain their position by at first growing prone and sending down
secondary rootlets into the sand. On the southernmost and most
exposed island of the group, Greater Sand Cay, an island that is
wind-swept to a degree not easily realised without a sojourn in these
tempestuous seas, and one that is often breached by the breakers
in several places during storms, this plant was scarcely represented
when I visited it in March 1911. A few young plants grew on the
weather side, and there were some seedlings growing amongst the
stranded drift. The presence of a few goats on the island may
partly explain this ; but, as shown below, the much hardier bushes
of Suriana maritima have suffered severely in recent storms, and
much of the vegetation growing on the beaches was swept away
under the combined influence of wave and wind during the last
hurricane.

On Grand Turk, the largest island of the group, the plant was
common in places on both coasts. It was thriving on Gibbs Cay,
ascending the sandy slopes some twenty or thirty feet; but I did
not observe it on Round Cay. On the rocky islands of Long Cay,
Pear Cay, and Penniston Cay, where beaches are absent or scanty, it
did not come under my notice at all ; and the same may be said for
Eastern Cay. On Cotton Cay I did not see it; but only a portion
of its coast was examined. On Salt Cay it did not often present
itself; but I found it flourishing near its southern extremity. On
Greater Sand Cay, as already observed, it barely existed. This
completes the list of the islands of this small group.

We come now to discuss the dispersal of this plant by birds and
by currents, and in these respects we will compare it with Sccevola
Kcenigii. There is no doubt that the fruits of both plants can be
distributed by birds as well as by the currents ; but, as has already
been pointed out, whilst the bird would be an effective agent in
local dispersal, as from island to island within the same group, it
is to the current that we must look for the agency concerned in
distribution over the breadth of an ocean. The importance of the
bird in the case of Sccevola Plumieri is emphasised by Dr. Millspaugh
in his paper on the Florida keys, where he remarks that " the black,
pulpy fruits of this plant form a very attractive food for land birds ;
it thus becomes scattered far throughout the Antillean region "
(p. 240). This is also the opinion of Krause, who would exclude the
possibility of current agency altogether (p. 14). However, neither
Millspaugh nor Krause refer to the results of any flotation experi-
ments, and the former was surprised when I showed him in the Turks
Islands a cup of sea- water in which the " stones " of Sccevola Plumieri
had been floating for several weeks. The bird for local distribution
and the current for oceanic transport : this was the conclusion
formed concerning Sccevola Kcenigii by Schimper and myself. It
applies also, as my West Indian results indicate, to Sccevola Plumieri.

In both cases the fruits, or rather their stones," are able to
float in sea-water for months, and in that of Sccevola Kcenigii for a
year or more, the seeds remaining fresh and, when tested, retaining

MISCELLANEOUS PLANTS

233

their germinative capacity. Yet, strange to say, the fruits of these
sister species, so similar in station and in habit, exhibit very different
types of buoyancy. In both cases the maintenance of the floating
powers depends on the " stone " ; but there the similarity ends. In
both plants the fresh drupe floats in sea-water, and the buoyant
stone is freed in a few days by the decay of the fruit. This, however,
is not the usual course of events in nature, since the fallen drupe
generally loses its soft parts whilst lying on the sand beneath the
bush, and it is the more or less dry stone that is swept into the sea.
The stones form a regular constituent of the smaller beach-drift in
the different parts of the tropics where the two plants grow.

I will first take the West Indian species, Sc, Plumieri. Should
the fresh black drupes get into the sea, experiment shows that they
will sink in two days, the buoyant stone, on being freed from the
decaying fruit, soon floating to the top. But, as just remarked, it
is the more or less bared stone that is usually picked up by the wave
from the beach. These stones, ovoid in form, prominently tubercled
on the surface, and 9 or 10 mm. in length, do not possess buoyant
tissue of any sort, neither the hard material of the stone nor the seed
within possessing any floating power. The outer cork-like covering,
which, as described below, endows the stones of Sc. Koenigii with
buoyancy, is not here represented. The floating capacity of the
stone of Sc. Plumieri is due to the circumstance that only one of its
two cells holds a seed. The empty cell, which is water-tight and
usually contains the seed envelopes, gives floating power to the
stone. This can be proved in different ways. The most striking
proof is this. If we take a buoyant stone and remove the portion
containing the empty seed-cavity, it sinks at once. But if we
remove the portion holding the seed, it floats still more buoyantly,
almost like a piece of cork. It does not follow that the two-celled
stones of this plant never have both cells filled with a seed. My
observations, however, indicate that stones with one cell empty
predominate. In fact, two-seeded stones very rarely came under
my notice.

Though it is usually the bared stone of Sccevola Koenigii that is
picked up by the waves as it lies on the beach, the fresh drupe may
at times be carried off by the sea. In that case it floats buoyantly,
and when after a few days' immersion it loses its white, fleshy cover-
ing, the stone remains at the surface. As studied in the homes of
the plant by Schimper (p. 172) and myself, the cause of the buoyancy
lies in a layer of cork-like, air-bearing tissue investing the stone
proper. If this covering is removed the stone sinks, neither the
hard material composing it nor the seeds possessing any floating
power ; and I may add that the two cells of the stone in each case
hold a seed, so that the question of buoyancy of the type presented
in the instance of Sc. Plumieri is not raised. It may be remarked
that the stone proper of Sc. Koenigii is much smaller than that of
the West Indian species, being rounded, about 5 mm. across, and
slightly tubercled.

The stones of the drupes of these two species of Sccevola represent
two quite different types of buoyant fruits, types that are described

234 PLANTS, SEEDS, AND CURRENTS

in Chapter XII. of my book on Plant Dispersal. Those of Sc. Koenigii,
which are described and figured by Schimper in his work on the
Indo-Malayan strand flora (p. 172, pi. vii.), belong to a type that
includes many of the characteristic littoral plants of the Indian and
Pacific Oceans, the buoyant tissue forming part of the fruit- coverings.
Since the question of adaptation was raised by Schimper in their
case I termed them the " adaptive " group, though not myself in
agreement with him on that point.

However, the interesting thing is that the type of buoyancy
represented by the stones of Sc. Plumieri is offered by plants where
this question of adaptation could not be raised. It corresponds
with the Premna type, which is discussed at length on pp. 112 and
561 of my book above quoted. The behaviour of the small drupes
of a littoral species of the genus is exactly that of the West Indian
Sccevola Plumieri, The Premna drupes floated at first, but the
buoyant stones are soon freed by the decay of the soft parts. Neither
the seeds nor the substance of the stone are buoyant, the stone
deriving its floating power from the fact that three of its four cells
are usually empty. The importance of the bearing on the question
of adaptation to dispersal by currents of the contrast presented by
the two shore species of Sccevola is obvious. If the buoyant quality
is accidental in its origin in one species, it is not reasonable to assume
that it is adaptive in the other.

The results of my experiments on the floating powers of the stones
of the drupes of these two species of Sccevola now require a few
remarks. As long ago as 1888 I tested the buoyancy of those of
Sc. Koenigii on Keeling Atoll, the results being given in my paper on
the plants of that locality which was published in the journal of the
Victoria Institute of London in 1889. Ripe fruits gathered from
the plant continued to float buoyantly after fifty days' immersion in
sea- water, losing during the early days of their flotation their white
fleshy covering. Subsequently three of the stones were sown out by
Dr. Treub at Buitenzorg, and out of the six seeds that they contained
five germinated in the course of the next two months. Twenty-one
months afterwards I put in sea-water in England two fruits gathered
on Keeling Atoll. Both floated after a year's immersion, the seeds
proving to be quite sound (see Plant Dispersal, p. 531, and Note to
the Keeling Atoll paper).

My first experiments on the fruits of Sccevola Plumieri were carried
out in the Turks Islands in 1911, the average result being that about
70 per cent, remained afloat after sixty-three days in sea-water.
The stones that had lost their soft coverings whilst lying under the
bushes on the beach sand were the most buoyant. About 60 per
cent, of the fresh stones and about 80 per cent, of the old dry stones
floated after six weeks. In all cases the seeds of the floating stones
proved to be sound and healthy at the close of the experiments.
It was ascertained that the sinking was due to water penetrating the
empty cell, the cell containing the seed being usually quite dry.
In later experiments made in England on stones that had been
collected ten months and still possessed sound moist seeds, I found
that 66 or 67 per cent, floated after eighteen weeks in sea-water.

MISCELLANEOUS PLANTS

235

But only half of the survivors proved to have been quite impervious
to water. In the other half, water had begun to penetrate into the
empty cavity as well as into the cavity containing the seed ; and as
they all sank in fresh-water the limits of their floating powers had
evidently been nearly reached. The upshot of the experiments was
that only a third of the stones were in a sound germinable condition
after eighteen weeks' flotation in sea- water ; and I would imagine that
a period of five to six months would represent their flotation capacity.

On the whole the results of experiments on the capacity for dis-
persal by currents possessed by Sccevola Plumieri and Sc. Kosnigii
go to show that although in both cases the stones will float unharmed
for months in the sea, the advantage is certainly on the side of the
plant last named. We would expect that floating capacity dependent
on the existence of buoyant tissue in the fruit-coverings would be
more effective than when determined by the failure of seeds and the
resulting empty cavity. Whilst the stones of Sccevola Koenigii will
float in sea- water for a year or more, those of Sc. Plumieri will on the
average float in a sound condition for only four or five months.
Those of the first-named species could very well be drifted across an
ocean as broad as the North Atlantic; but this would not be prac-
ticable for those of Sc. Plumieri, their floating powers only allowing
them to reach Bermuda from the Florida coasts, the transatlantic
traverse, occupying twelve months and more, being impracticable.
But although the transference of Sc. Plumieri from the New World
to West Africa by the only available route in the Gulf Stream drift
would be impossible, the passage from tropical West Africa to Brazil
in the Main Equatorial Current would be quite within the floating
capacity of its fruits, since, as shown in Chapter III., it could be
performed in three months. I have not here referred to the possi-
bility of a passage to West Africa in the Counter Equatorial Current,
since there is little to indicate that it is an available route for seed
dispersal.

When, therefore, we discuss from the standpoint of dispersal by
currents the question whether Sccevola Plumieri has reached the
West Coast of Africa from America, or the Atlantic coasts of America
from Africa, we have to exclude the long easterly passage in the
Gulf Stream drift in preference for the westerly passage in the swift
Main Equatorial Current from the Gulf of Guinea to the coasts of
Brazil. From the standpoint of distribution a consideration of the
same question leads to the same results. There is no probability
that the American region could have received this plant from across
the Pacific. Although Australia is the home of the genus. Sc.
Plumieri does not occur there, or, in fact, anywhere in that region
of the globe. We have, therefore, to choose between America as
the birthplace of the species or America as its recipient from the
African West Coast. Although in the Index Kewensis America is
credited with two endemic species of Sccevola, one in Trinidad and
the other in Central America, these are both disregarded by Krause,
who includes the species of the second locality {Sc. cumana) amongst
his doubtful species (p. 168). No species of the genus is mentioned
in Hart's list of the Trinidad flora. There is, therefore, little reason

236 PLANTS, SEEDS, AND CURRENTS

for supposing on the grounds of the distribution of the genus that
America is the birthplace of this species. All the indications favour
the view that it has received it from the shores of the nearest portion
of Africa.

In the case of Sccevola Plumieri another difficulty presents itself
in connecting its ranges on the East and West Coasts of Africa.
Though it reaches the Cape or its vicinity on the east side of the
continent, there seems to be a gap of about twenty degrees of lati-
tude on the west side between the Cape and Benguela, where, accord-
ing to the data supplied by Krause, it is next found. Probably
future records will bridge over this broad gap; and we can only
suppose that the species originally found its way north along the
African West Coast through the combined agencies of birds and of
inshore northerly currents. That it reached this coast from the
eastern side of the continent is very probable. This involves the
doubling of the southern extremity of Africa ; but it has been shown
in Chapter III. that this has been performed by bottle-drift.

Tabulated Results of the Comparison op Scjevola Plumieri, Vahl,

AND Sc^VOLA K(ENIGII, VaHL.

Scaevola Plumieri

Scaevola Kcenigii

Distribution.

Pacific coast of tropical
America and the Galapagos
Islands.

East coasts of tropical
America from Florida to Rio
de Janeiro, including the West
Indies and Bermuda.

West Coast of tropical Africa
from Senegal to Benguela.

East Coast of tropical Africa
from Somaliland southward
and extending to the Cape. It
reaches eastward to Southern
India, Ceylon, and Mauritius.

Islands of the Indian Ocean
extending westward to the
Malabar coast, the Seychelles
and Madagascar, but not re-
corded from the east coast of
Africa.

South-eastern Asia, extend-
ing north to the Liu-Kiu
Islands and eastward through
Malaya to New Guinea and the
northern coasts of Australia.

Islands of the tropical Pacific
as far east as the Low Archi-
pelago and as far north as the
Hawaiian Islands.

Characters of
fruit.

Black juicy drupe. Stone
ovoid, markedly tubercled, 9
to 10 mm. long, no covering
of buoyant tissue, two-celled,
one cell empty.

White fleshy drupe. Stone
roundish, slightly tubercled,
5 mm. across, possessing an
outer covering of cork-like
buoyant tissue, two -celled,
both cells holding a seed.

Buoyancy of
fruits in sea-water.

Stones float for four or five
months with seeds sound.

Stones float for twelve
months and more with seeds
sound.

Cause of the
floating capacity.

Buoyancy of stone is en-
tirely due to the empty cell.

Floating power of stone is
entirely due to the buoyant
tissue investing it.

Agents of dis-
persal.

Currents across tracts of
ocean.

Frugivorous birds for local
dispersal.

Currents across oceans.
Frugivorous birds for local
dispersal.

MISCELLANEOUS PLANTS

237

SOPHORA TOMENTOSA, L.

This littoral shrub, which ranges over the warm parts of the globe,
is discussed at length in my book on Plant Dispersal. My remarks
here will be accordingly restricted to some supplementary observa-
tions made in the West Indian region. Though widely distributed
in the West Indies and extending to South Florida and Bermuda
and along the Caribbean shores of Central America to Brazil, it does
not appear to be of frequent occurrence. Whilst typically at home
on a san^y beach, it may also grow on rocky shores, as occasionally
happens in Jamaica and, according to Harshberger's work (p. 674),
also in Cuba.

The plant came under my notice more particularly on the north
coast of Jamaica, in the Turks Islands, and on the Colon beaches.
In the Turks Group it only came under observation in one island,
namely, on Grand Turk; and there it was frequent in the interior
of the low, sandy southern third of the island, where it grew in the
company of Coccoloba uvifera, Dodoncea viscosa, and other plants,
but was never observed amongst the vegetation immediately border-
ing the beach. The beach conditions are, however, reproduced in
the plains of the interior, where the plant thrives at distances never
exceeding half a mile from the beach. It appears to have a difficulty
in establishing itself on low, sandy islets in these seas on which many
characteristic shore shrubs find a home. Thus, Mr. Lansing did not
record it on the Florida sand-keys, of the vegetation of which he
made a most methodical investigation. As illustrating its transient
sojourn on small isolated island groups one may refer to a note on
this subject by Mr. Savage English in the Kew Bulletin for 1913.
He refers to a solitary specimen on the shore of Grand Cayman which
was washed away in the hurricane of 1912.

In the district of St. Anne's on the north side of Jamaica I had
an opportunity of observing the influence of an inland station on the
buoyancy and size of the seeds. The seeds of the strand plant, as
is shown in my previous work, are able to float in sea-water un-
harmed for several months, and even after twelve months' immersion.
It is also established in its pages that with the seeds or fruits of
typical beach plants like Ipomoea pes-caprcE, Sccevola Koenigii, etc.,
the buoyant capacity is as a rule maintained when the plants have
extended inland several miles from the coast. This conclusion is
generally supported by the behaviour of Sophora tomentosa in
Jamaica; but at the same time it was elicited that although the
seeds of the inland plants floated in sea- water as long as those of the
beach plants they did not do so in the same proportion, a greater
number of them sinking during the experiment — a result, however,
that is to be connected with the moister climatic conditions of the
inland station.

I found the plants well established at the roadside and on the hill-
slopes just below " Sussex," which lies at the back of St. Anne's
about two miles inland and about 700 feet above the sea. Their
seeds were compared with those of shore plants growing at the
St. Anne's coast on Priory Islet. The estate known as " Sussex "

238 PLANTS, SEEDS, AND CURRENTS

lies a little below the zone of heavy rainfall ; but the climatic con-
ditions there are far more humid than on the coast beneath. This
distinction is important, because it is bound up with different degrees
of shrinkage of the coast and inland seeds, and with the consequent
different degrees of impermeability. As indicated below, the coast
seeds are smaller and lighter, contrasts which my observations on
seed-impermeability enable me to connect with a greater degree of
imperviousness resulting from more complete shrinkage of the seed-
coats. The coast seeds were 5-5 to 6 mm. in size and averaged
1-3 grains in weight; whilst the inland seeds measured 6-5 to 7 mm.
and had an average weight of 2 grains.

The difference in behaviour is at once shown in an experiment
in sea-water commenced by me in Jamaica, continued there by
Mrs. H. B. Warde after I had left for England, and concluded by
me on my return to the island about half a year afterwards. Of the
coast seeds, 95 per cent, were afloat after seven and a half months,
and no more sank when the experiment was extended to nine months,
the seeds being still hard and sound. Of the inland seeds some
began to swell and sink after two months; but 60 per cent, were
afloat, and hard and sound, after seven and a half months. Some
of the sunken inland seeds germinated in the sea- water and plants
were raised from them. In another sea- water experiment carried
out by me in Jamaica the contrast in behaviour was greater. After
a month all the coast seeds were afloat in their normal state; but
several of the inland seeds began to swell in a few days, some of
them germinating in the sea-water, and only 10 per cent, remained
afloat in a hard, sound condition after a month. In a third sea-
water experiment conducted in England in the same year, under
warm conditions imitating those of the tropics, all the coast seeds
were afloat and normal after four months, whilst 69 per cent, of the
inland seeds alone floated ; the rest, having absorbed water, swelled
and sank. All the seeds employed in these experiments were of the
previous season's gro\\i:h. It appeared in the course of this inquiry
that the " scar " was the place of weakness in the inland seeds as
regards the penetration of water.

The seeds experimented upon were gathered from the well-dried
pods hanging on the coast and inland trees at the end of March 1907.
In both localities the previous year's pods were hanging in bunches
from the trees. In neither locality were the trees then in flower;
and whilst the coast plants were leafless, the inland trees displayed
abundant foliage, a contrast connected with the prevalence of more
humid conditions in the inland station.

The bearing of these Jamaican experiments may be thus stated.
My experiments in the Pacific on the influence of an inland station
on the buoyancy of the seeds or fruits of typical shore plants were
concerned with plants that had extended miles inland in dry districts
where plants of the xerophilous habit prevailed. Here in Jamaica
we had typical shore j^lants invading the fringe of the lower forest
zone, where more humid conditions determined the hygrophilous
habit. The results obtained in Fiji and those obtained in Jamaica
are therefore in one sense not strictly comparable. In the first

MISCELLANEOUS PLANTS

239

case, the xerophyte of the beach found conditions suited for xero-
philous plants in the dry inland districts ; whilst the fruits matured
and the seeds underwent the shrinking and hardening process under
somewhat similar circumstances in both stations. In the second
case, the xerophyte of the beach was placed under different climatic
and soil conditions in the lower forest zone. The fruits matured
and the seeds hardened in a moister climate, and we have seen
how the whole plant responded, since the inland plants were in
full leaf in the spring whilst those on the beach were leafless.

The conclusion to be drawn from these experiments is, that whilst
the buoyancy of the seeds of littoral plants is retained when the same
plants grow inland, whether in moist or dry conditions, it is less
persistent when the inland plants grow in the humid conditions of
the lower woods than with those growing in plains or open-wooded
districts where drier xerophytic conditions prevail. The buoyancy
is retained, therefore, when the xerophytic conditions of the coast
are preserved in inland plains. It tends to disappear under the
moist conditions of the inland forests. We have here indicated
how it comes about that in a genus holding both littoral and inland
species the seeds or fruits of the former float and of the latter sink.
This is illustrated in the case of Sophora in the Pacific islands, where
the seeds of the wide-ranging shore species, S. tomentosa, float, and
those of the inland species, as exemplified by S. chrysophylla of the
Hawaiian forests, sink.

It is probable that Sophora tetraptera, a tree of New Zealand and
South Chile, which grows at the coast but also grows inland, would
display buoyant seeds only when growing at or near the coast.
In an experiment on the seeds of the tree that I collected on the Chilian
coast it was found that half of the seeds floated in sea- water after
seven months' immersion. Two of them placed in soil germinated
and produced healthy plants. This is an extension of an experiment
described on p. 580 of my work on Plant Dispersal.

A word may here be said about the source of Sophora tomentosa in
the New World. As far as the currents are concerned, it is far more
likely that its floating seeds reached Brazil by the short route in
the Main Equatorial Current from the Gulf of Guinea than that they
were carried in the Gulf Stream drift from the West Indies to Africa.
Yet the genus holding some thirty species is spread over the warmer
regions of both hemispheres. North America has its own species
that flourish in the prairie districts, in the North Mexican highlands,
and in the Rocky Mountains (Harshberger's Phyt. Surv. N, America).

SURIANA MARITIMA, L.

This shrub, the sole species of the genus, is one of the most widely
spread of tropical strand plants. It occurs in the Pacific islands,
on the northern coasts of Australia, in Malaya, in the islands of the
Indian Ocean, on the shores of the Asiatic mainland, on the East
Coast of Africa, but not, as far as I know, on the West Coast of that
continent, though its occurrence there is extremely probable. In
the New World it is widely spread over the West Indies, occurring

240 PLANTS, SEEDS, AND CURRENTS

even on such isolated groups as the Cayman Islands and the Alacran
Shoals (Millspaugh). It is also a Bermudian plant. On the American
mainland it is found on the coasts of South Florida and on the shores
of the Gulf of Mexico. I have no record of its occurrence on the
Pacific coasts of that continent, but it ought to grow there.

There are, however, some curious gaps in the distribution of a
plant that Nature evidently intended to be universal on tropical
shores. For instance, its distribution in the Pacific is freak-like.
It has been recorded from Tonga, but not from Fiji or Samoa. Yet
it occurs in the Melanesian archipelagoes of the Western Pacific.
Though found in the Tahitian Group and in the Paumotu Islands,
it has not been observed in Hawaii. We have here, it would seem,
an outcast in the plant world, friendless, without kith or kin, and
claimed by nobody, since botanists are undecided in what order to
place it. It would be futile to seek for its home. It is probably
coeval with man in the tropics, and he has evidently been its greatest
foe.

Its suitability for firewood no doubt explains its otherwise unac-
countable absence from some of the Pacific archipelagoes. One
of the first things a Pacific islander does, when he lands on an unin-
habited shore, is to gather fuel for cooking his yams or his taro-
roots ; and if, as often happens on coral islands, fishing parties make
a sojourn there of some weeks, the wood of this shrub would be
burned in quantities. This inimical influence would not be an affair
of to-day but of the ages. It goes to explain why the plant was
not recorded by botanists from Keeling Atoll before my visit in 1888
{vide Keeling Atoll paper), since long before the white man's occupa-
tion of the islands they had probably been visited from time to
time by Bugis traders.

Though typically a plant of the borders of the sandy beach and
of the sand-dune, it may also grow on coastal rocks as in Bermuda
and in the Bahamas (Harshberger). I came upon this shrub growing
on the north coast of Jamaica at St. Anne's, and at Dry Harbour
and on the south coast at Paroti Point. But it was in the Turks
Islands at the south-east end of the Bahamas that I paid especial
attention to it. However, before proceeding to reter to its occurrence
in that small group I will notice its distribution in the sand-keys
of Florida, as observed by Mr. Lansing and described by Dr.
Millspaugh. Out of nineteen keys examined westward of Key West
this plant was noted in all but two; but usually it was infrequent
and represented by only one or two small colonies growing in its
natural station on the sandy soil to the rear of the mangrove belt.
Only in four keys was it at all frequent, and in two of these it occupied
most of the surface of the islet. In the past, no doubt, man did much
to disturb the distribution of this plant in the Florida keys by
utilising it for firewood

In the Turks Islands, though a characteristic strand plant, it as
a rule presents itself in the rear-line of the beach vegetation when
any arrangement can be detected. But it is equally at home on
the sand-dunes behind the beach ; and in the smaller cays, when
sand has been spread over the island, it also occupies the interior

MISCELLANEOUS PLANTS

241

in association with other plants from the beach. It grows, often
in abundance, on nearly all the islands; but it did not come under
my notice either on Round Cay or on Eastern Cay. Its absence
from the last-named island, which is the most weatherly of the group,
may be partly due to its use for firewood by visiting parties, either
from Grand Turk or from passing schooners, since it thrives on the
neighbouring Pear Cay, which from the difficulty of landing is much
less frequently visited. But it maybe that hurricanes have assisted
in its banishment from this cay, as is illustrated by the destruction
executed amongst its numbers on Greater Sand Cay, as noticed below.
On Pear Cay it displayed a singular adaptation to the wind-pressure,
the trunk and primary branches being prone and rooting in the sand,
whilst the leafy branches alone rose erect three or four feet into the
air. On Greater Sand Cay I found it fairly well distributed in
February 1911; but my boatmen told me that before the last
hurricane of 1908 it was much more frequent — a statement confirmed
by the number of dead prostrate trunks still to be seen on the surface
over the island, the material being utilised for firewood by small
sailing craft trading in these seas. The shrub is frequent around
the coasts of Grand Turk, and in places where the beach vegetation
borders on the mangrove belt one may sometimes see a curious
intermingling of the plants of the two formations, Suriana maritima
with other beach plants growing amongst the mangroves. Though
preferring a sandy soil, where it grows in colonies, the plant also
grows well on rocky ground, but only as individuals.

On the Turks Islands there is evidently from some cause or another
great loss of seeds. In two localities I found that 95 per cent, of
the seeds or seed-like fruits gathered from the plants were empty,
whilst of those picked up from the sand beneath the bushes 30 to
40 per cent, had sound kernels. The seeds, which are about 3J mm.
long and broadly conical, have a dark wrinkled hairy skin, which,
however, they soon lose in the beach-drift, and then they are about
3 mm. in size and have a smooth reddish surface. In appearance
they look a little like grape-seeds, and no doubt their hardness
might fit them for dispersal in the stomachs of birds; but their
great floating powers offer a much readier explanation of the world-
wide distribution of the species. Dr. Millspaugh regards the seeds
as dispersed through the medium of the feet of sea-birds; but the
currents aided by the drifting log and floating pumice have doubtless
done most of the work of distribution. There is nothing in the
character of the dryish fruits on the plant to attract frugivorous
birds.

Hemsley in his list of plants dispersed by oceanic currents includes
this species {Chall. Bot, L, 42, 48); and Schimper, who especially
investigated the buoyancy of the seeds, came to the same conclusion.
I may add that the term " nucule *' is applied to the seed-like fruits ;
but they are for purposes of distribution " seeds," and I will follow
Schimper in this respect. They lie in numbers on the sand near the
shrubs; and in the Turks Islands they are prominent amongst the
small drift derived from local plants and sorted out on the beach by
wind and wave. In this fine drift the seed-like fruits of Suriana

242 PLANTS, SEEDS, AND CURRENTS

maritima are associated with the pyrenes of Tournefortia gnaphalodes,
the seeds of Iporncea, the " stones " of Sccevola Plumieri, and well-
rounded small pumice pebbles, 5 to 12 mm. in size.

These seeds, as I have said, could readih^ be carried in the crevices
of floating logs, or in the cavities of floating pumice, such as is
stranded on the beaches of tropical regions all over the world. But
it is on their great floating powers, which fit them for dispersal by-
currents, that we must mainly rely. .Neither the kernel nor its
hard covering has any buoyancy, the floating power arising, as also
ascertained by Schimper (p. 163), from the unfilled space in the seed-
cavity. In my paper on the plants of Keeling iVtoll I refer to some
experiments there made which only indicated a capacity of floating
between two and six days in sea- water ; but as the seeds are described
as rather soft, it is evident that they were immature. Schimper in
an experiment made at Bonn (p. 165) kept the seeds afloat in salt-
water for nearly five months (143 days) ; and my experiments in
Jamaica and the Turks Islands point in the same direction. Thus
in Jamaica some seeds which had been floating in sea- water for seven
weeks were quite sound at the close of the experiment. In the
Turks Islands I placed sixty seeds in sea-water and after nine weeks
forty-five were floating buoyantly, and would evidently have floated
for a much longer period. Of the seeds that sank nearly all were
empty; whilst of those that remained afloat nearly all had dry
sound kernels and dry cavities.

SwiETENiA MAHAGONi, Jacq. (Mahogany)

In one's inability to explain its mode of dispersal over the West
Indian area and the mainland of tropical America, this tree must be
typical of many other trees of the forests of this region. Having
made a special study of the fruit in Jamaica, the results of whicifi
are given in my work on Seeds and Fruits, I here give a few remarks
on the plant from the standpoint of dispersal.

Belonging to a genus of only three or four species that are restricted
to the tropics of the New World, this tree does not raise awkward
questions, such as are presented by genera common to the eastern
and western hemispheres. Yet queries almost as difficult to answer
are implied in its occurrence in the larger West Indian islands.
Its distribution in South Florida, Mexico, Central America, and Peru
may be a matter of the continuity of the land-surface, and there is
much, as far as the plants of the Greater Antilles are concerned,
to support the contention of the geologist that with those large islands
in past ages distribution was also a matter of the continuity of the
land-surface. The occurrence of the Mahogany tree in the Greater
Antilles and in most of the larger islands of the Bahamas suggests
questions that are concerned with former continental connections
rather than wdth means of dispersal.

The large winged seeds, two and a quarter inches in length, that
are freed by the dehiscence of the capsule, are quite unfitted for
transport by the currents. In experiments they can float a week
or two; but they absorb sea-water and become sodden and dead,

MISCELLANEOUS PLANTS

243

and they arc much too fragile for transport over the sea. It is
possible that strong winds might carry the seeds some distance ;
but experiment showed that this would not be greater than 100
feet in a moderate gale.

Symphonia globulifera (L. fiL)
(syn. Moronobea coccinea, Aubl. Mart.)

This West African tree of Upper and Lower Guinea is found in
the New World in Jamaica, Dominica, Trinidad, Guiana, North
Brazil, Panama, etc. Its station is by the riverside in mountain
woods, and in the swampy ground bordering estuaries, but above
the mangrove formation. In Jamaica I observed it flourishing at
the waterside on the banks of the Black River estuary ; and accord-
ing to Forrest Shreve, as quoted by Harshberger (p. 679), it grows
in the forests of the Blue Mountain Range, forming with Calophyllum
calaba and other trees closed arches over the rivers. The genus
has a remarkable distribution, though it may be in part explained
by our better acquaintance with the floras of some localities than
of others. Of its dozen or more known species nearly all are peculiar
to Madagascar; but two are West African, and one of these, S.
globulifera, is the widely spread New World species that we are now
considering.

Its germinating seeds occurred in abundance in the floating drift
of the Black River estuary. In Jamaica it is known as " Hog- gum "
or " Boar-wood." Its softish, baccate fruits, which have a yellow
juice, are one- and- a- half to one-and-three-quarters of an inch long, and
hold from one to three seeds, one to one-and-a-quarter inch in length,
which are at first fleshy and afterwards tough and flexible. The
mature seeds, when freed by the decay or breaking down of the fruit,
are not in any way protected by their coverings against drying
or against the penetration of water; and when removed from the
fruit they shrink greatly. Their readiness to germinate, whilst
afloat in the Black River, is thus explained ; and I may state that
quite 95 per cent, of the seeds there observed were germinating.

The seed presents the structure characteristic of several other
genera of the Guttiferce, a structure also illustrated in the Barringtonice.
There is a central axis separated from the outer thick portion by
a thin layer of vascular tissue (Mirbel's membrane), which becomes
wavy or crumpled in the drying seed. The cotyledons are either
absent or are represented by minute scales, the seed being, therefore,
merely an enlarged hypocotyl.

When we reflect on the unprotected condition of the fruit and its
seeds, on the fleeting vitality of the seeds, on their readiness to
germinate when afloat in river-drift, and on the fate that must
await them when they reach the sea, it is not possible to find an
explanation of the plant's distribution on the opposite sides of the
Atlantic in dispersal by currents; and it would be equally futile
to look to the agency of birds. We may even go further and hold
that the seeds are not even suited for inter-island dispersal by either
agency in the West Indian region. Taking the arrangement of

244

PLANTS, SEEDS, AND CURRENTS

land and sea as it is at present, the distribution of this tree offers
one of the most difficult problems dealt with in these pages.

Thespesia populnea, Corr.

This tree has presented itself to me as a littoral plant in several
parts of the tropical zone, namely, in Hawaii, Fiji, the Solomon
Islands, Keeling Atoll, and in different islands of the West Indies.
Its distribution over the tropics of the Old World and its mode of
dispersal by currents are discussed in my book on Plant Dispersal ;
but I did not there regard it as belonging to the New World, being
guided in this matter by Bentham, who in his Flora Ausiraliensis
regards it as introduced into America. However, there can be
little doubt that it behaves in the West Indies as an indigenous
plant ; and, considering its great capacity for dispersal by currents,
there seems in the light of more recent investigations but small
reason for the refusal of its proper place in the flora of the New
World. " Quod credere vix possum " is Urban' s opinion concernmg
the belief of botanists that it has been introduced into America {Symb.
AntilL, IV., 401). If the distribution of the genus given in the Index
Kewensis offers a clue, the New World can almost make an equal
claim to be the home of this tree. Of the seven other species there
named, three are peculiar to Mexico, the West Indies, and Brazil,
respectively ; one is only found in Africa ; and three are confined to
Malaya. It is, however, quite possible that in some distant age
the tree reached the New World from tropical West Africa, where
it is now at home, since the seeds could have been readily carried
across to Brazil in the Main Equatorial Current.

It is distributed over the Greater and Lesser Antilles and is found
in Trinidad (Hart). I especially observed it in St. Croix, Jamaica,
Grenada, Tobago, and the Turks Islands. In order to prove that
it behaves as an indigenous shore tree in the West Indies it is of
importance to name its associates. I found it thriving at the beach
border on St. Croix in the company of such characteristic littoral
trees and shrubs, as Coccoloba uiifera, Guilandina honducella, and
Hippomane mancinella. Harshberger states that on St. Croix and
the Virgin Islands it is one of the Coccoloha-Hippomarie association,
the formation of trees and shrubs that immediatelv lines the beaches
(p. 686).

Grisebach speaks of it as growing along the sea-coast of Jamaica,
and I made notes of its associates in different localities on the shores
of that island. On the beaches of the Black River district it was
associated with Coccoloba uiifera, Ecastaphyllum brozvnei, and
Guilandina bonducella. In the Savanna-la-mar district a mangrove
fringe often skirts the low sandy shores, and on the beach behind
it this tree thrives in the society of Guilandina bonducella, Coccoloba
uvifera, and Conocarpus erectus, one of the most typical strand
shrubs of the West Indies. It is associated with the same three
plants on the borders of the beaches on the north side of the island,
as at St. Anne's Bay and at White River, and to them we may
add Sophora tomentosa, another characteristic beach shrub. With
Coccoloba ucifera it is one of the commonest of the plants bordering

MISCELLANEOUS PLANTS

245

the beaches along the east coast of Tobago ; and in the company
of the same plant together with Guilandina bonducella and Hippo-
mane mancinella it grows at the margin of the beach south of St.
George's Harbour in Grenada.

There can, therefore, be but little doubt that Thespesia populnea
behaves like an indigenous strand plant in the West Indies. If
its exclusion from the proper flora of the New World is based on the
assumption that the genus has its home in the eastern hemisphere,
then we should have to exclude such a typical West Indian beach
plant as Scccvola Plumieri and such representative West Indian
swamp plants as Rhizophora mangle and Carapa guianensis.

Against the view that it is truly American are to be urged the
facts that the tree has not established itself amongst the new vegeta-
tion of the Florida sand-keys and is regarded as introduced into
Bermuda {ChalL Bot., II., 22). It is, however, widely spread over the
Pacific, occurring in some of the most remote islands; and it is
difficult to imagine how a characteristic shore tree that is of no great
use to man and is exceptionally suited for dispersal by currents
could owe its wide distribution, except in a secondary sense, to
human agency.

In the Turks Islands the tree gave me the impression of being
indigenous, though now it could merely be viewed in the light of
a survival, since it came under my notice only in the northern part
of the island of Grand Turk. Here it grows gregariously inland
on one side of the hollow known as the North Wells, but it also grows
on the borders of the neighbouring coast. I should imagine that
originally the tree thrived around the lagoons on the beach behind
the mangroves, as it often does in the Pacific. In Grand Turk and
Salt Cay the salt industry has led to the destruction of most of the
original vegetation on the lagoon shores, and Thespesia populnea
was probably involved in this clearance.

In the West Indies one not uncommonly finds Nature engaged in
distributing this plant. The dried baccate capsules and the seeds
are not infrequent in beach-drift, the fruits liberating by their decay
the buoyant seeds, which are readily swept off by the waves. In
some localities in Jamaica I noticed seedlings growing freely in the
stranded drift.

It is strange that notwithstanding its capacity for dispersal by
currents this tree is stated by Lefroy to have been introduced by
man into the Bermudas {Chall. Bot., II., 22). In this matter it is in
the same category as Hibiscus tiliaceus, which, as before pointed out,
is not included in the indigenous flora. In many respects, as in
its general distribution as a littoral tree in the warm regions of the
globe, in its fitness for dispersal by currents, and in the wide preva-
lence of the same native name in the Pacific islands, it raises the same
issues as Hibiscus tiliaceus ; but there is this difference, that it is
not of such great use to man, at least among the Pacific islanders,
and the uncertainty whether it owes much to human agency in its
distribution, a matter to which Hemsley refers {Chall. Bot., IV., 235),
is for this reason more pronounced than with the other tree.

Since I did not deal connectedly with this tree in my previous

246 PLANTS, SEEDS, AND CURRENTS

work on the Pacific, I will go briefly over the ground there traversed
as regards its distribution and modes of dispersal, supplementing
my remarks with additional observations and reflections and directing
them towards the elucidation of the problem connected with the
intervention of man. It resembles Hibiscus tiliaceus closely in its
general distribution, accompanying it as a common seashore tree
throughout the archipelagos of the tropical Pacific, in North Australia,
in Indo-Malaya, in the islands of the Indian Ocean, on both coasts
of Africa, and in the West Indies ; but, as far as I know, only Hibiscus
tiliaceus has been recorded from the Pacific coasts of America,
though it is very probable that Thespesia populnea also grows there.

The testimony of botanists in the Pacific islands as to its claim
to be indigenous, that is to say, to have existed there at the time of
their discovery in the eighteenth century is practically unanimous.
It was found during Cook's voyages by Banks and Solander in the
Society Islands and by Forster in Easter Island (Seemann, p. 18) ;
whilst Hillebrand, the authority for the Hawaiian Islands, places it
with the plants that were introduced by the natives in prehistoric
times. Hemsley, Burkill, and Reinecke in the case of the Tongan
and Samoan floras, Cheeseman as concerning Rarotonga, and
Seemann in respect of Fiji, include the tree amongst the indigenous
plants without any comment.

If as Hillebrand claims, and his opinion is always weighty, the
Polynesians have carried these seeds about with them during their
oceanic migrations, what, we may ask, were the inducements for them
to do so ? Though like Hibiscus tiliaceus the tree yields bast fibres
which are used for cordage in other parts of the world, it does not
seem, according to Cheeseman, Hillebrand, Reinecke, Seemann,
etc., that the Polynesians and Fijians utilised it for this purpose.
In fact, it was for the durability and hardness of its timber that the
Fijians, Rarotongans, and Samoans chiefly prized it. Hillebrand,
however, finds sufficient explanation of its wide distribution in the
Pacific in the veneration paid by the Tahitians and other islanders
to the tree.

I am inclined to consider that the Pacific islanders may have
assisted in the distribution of this tree, but not to the extent in which
they aided the dispersal of its frequent associate on the seashore,
Hibiscus tiliaceus. But whatever was accomplished in this direction
by man was probably carried out ages ago. Oliver, in his Flora
of Tropical Africa (1868-77), considered it as probably distributed
through cultivation. It is worth noting that another species of
the genus, Thespesia danis, from east tropical Africa was held sacred
in the Galla country (Hooker's Icon. Plant, ser. iii., Vol. IV.). Though
doubtless its presence on isolated oceanic islands in the Pacific is
usually due to currents, I am inclined to hold that in the case of
Easter Island, where it was found by Forster in 1773, during Cook's
second voyage, its existence should be attributed to man.

We pass on to advocate the claims of the currents in explaining
the wide range of this coast tree. Hemsley, though regarding it as
introduced into the New World, ascribes to currents a share in its
distribution {Chall. Bot., I., 42; IV., 125, 235). My first experiment

MISCELLANEOUS PLANTS

247

on its fitness for dispersal by this agency was made in the Solomon
Islands in 1883. Since that time I have tested the capacity in the
Keeling Islands, in Hawaii, Fiji, and other localities (Solomon
Islands, 1887, p. 305; Journ. Vict. Inst. London, 1889; Plant
Dispersal, 1906, p. 531), all the experiments giving the same indica-
tions and culminating in one where, after floating a year in sea- water,
a see^ -germinated and developed into a plant. The dried fruits,
which lie in numbers under the trees, are, as already observed, very
likely to be swept off the beach by the waves. They float, but in
time break down, thus liberating the buoyant seeds on which the
dispersal by currents eventually depends. In the West Indies the
dried fruits, seeds, and seedlings produced from stranded seeds are
characteristic of the beach-drift, and the same may be said of the
Hawaiian Islands. In the Solomon Group I found that this was
one of the early plants that established themselves on the low sandy
islets of the coral reefs (Chall. Bot., IV., 309). In the Marquesas,
according to Jouan, it is only found on the seashores in places to
which the waves could have conveyed the seeds (Ibid., IV., 125).
In my Victoria Institute paper above quoted good reasons are given
for the belief that the Keeling Islands possessed the tree at the
time of their first occupation by white men about 1825, and that
they received it with many other of their shore plants through the
instrumentality of the currents.

The indications of the foregoing discussion are that whilst, as
with Hibiscus tiliaceus, man and the currents have each played their
part in distributing the species, the currents have perhaps had a
rather more important share in the process than in the case of
Hibiscus tiliaceus. However, I hope at some future time to discuss
the distribution and dispersal of Thespesia populnea in greater
detail.

TOURNEFORTIA GNAPHALODES, R. Br., and TOURNEFORTIA ARGENTEA,

Linn. f.

The distribution of these widely spread littoral species of Tourne-
fortia raises several of the questions presented by the two shore
species of Sccevola before dealt with. Sc. Plumieri and Sc. Kcenigii.
One of them, T. gnaphalodes, is found over the West Indies including
the Bahamas, in South Florida and the adjacent keys, in Bermuda,
and on the coasts of Mexico and Yucatan, but not apparently on
the Pacific coasts of the New World. The other, T. argentea, is
spread over most of the continental and insular coasts of the Indian
and Pacific Oceans in warm latitudes. It has also extended from
the East African to the West African coast, being found on the
shores of Lower Guinea (Oliver's and Dyer's Flora of Tropical Africa,
Vol. IV., sect 2, p. 29). Unlike Sccevola, however, the two species
never meet, being separated from each other by the breadths of the
Atlantic and Pacific Oceans. We have here also a New W'orld
and an Old W^orld species dividing the tropical beaches of the globe
between them, but the American species of Tournefortia is appro,
priated by the New W^orld, whilst the American species of Sccevola

248 PLANTS, SEEDS, AND CURRENTS

occurs on both coasts of Africa. We are thus face to face with
problems of a different nature.

This is seemingly not such a well-defined genus as Sccevola. It
holds more than 120 species, distributed over the tropics and sub-
tropics of the globe; and since the New World possesses its own
peculiar species, it may be inferred that Tournefortia gnaphalodes
could have had an independent origin on this continent. Hemsley
states that there are several littoral species. One of these, as
I infer, is T. sarmentosa, Lam., which extends from the Philippines to
North Australia and occurs also in Mauritius and in the Seychelles
(Bot. Chall, IV., 168).

Like the two shore species of Sccevola, those of Tournefortia possess
fruits endowed with great floating powers, and are thus well fitted
for dispersal by currents. However, they differ from the Sccevola
plants in that the fruits of both species exhibit the same type of
buoyancy. There is a much greater resemblance, both in habit
and general appearance, between the two shore species of Tournefortia
than in the case of the other two plants. Covered with hairs, which
give them a silver-grey hue, these shrubs form a conspicuous feature
in the shore landscape, their height ranging usually up to five or
six feet, but much reduced in exposed situations.

I will now deal more in detail with these two species of Tournefortia
from the standpoint of dispersal by currents. Both of them possess
dry drupaceous fruits, measuring about seven millimetres in the
case of T. gnaphalodes and somewhat less in the case of 2\ argentea.
When naturally dried, these fruits separate with a little pressure into
two hemispherical pyrenes, and it is in this condition, but bared of
their outer dark skin, that they usually occur in the old drift of beaches.
Each pyrene displays a suber-like exocarp, in which lies imbedded a
small two-celled stone, each cell usually containing a seed. Deprived
of its outer covering the stone sinks.

[Particulars relating to T. argentea will be found in Schimper's
work on the Indo-Malayan strand flora (p. 174), in my Plant Dispersal
(p. 108, etc.), and in my paper on Keeling Atoll in the Journal of the
Victoria Institute (1889)].

A familiarity with both species in their homes enables me to treat
them together here. The fruits of both plants, entire and in halves,
are of common occurrence in the smaller drift of beaches on which
they grow. They cover the sand in quantities beneath the bushes,
and the strong winds scatter them over the beach. So frequent were
they on some of the beaches of the Turks Islands that they were
to be noticed in every handful of sand. Under the shrubs they are
apt to germinate, as was often indicated on Grand Turk by the
shrivelled projecting radicles that had withered up before they could
establish themselves in the sand. I noticed both on Keeling Atoll
and on Grand Turk that the pyrenes are at times mixed with the sand
washed into the crevices of stranded logs. This matter is especially
discussed in my paper on Keeling Atoll ; and it is there shown that
floating pumice must also often assist dispersal in the same manner.
But although drifting logs and floating pumice often aid dispersal,
they do not determine it, since the buoyant fruits of these two

MISCELLANEOUS PLANTS

249

species of Tournefortia are of themselves able to cross the broadest
ocean.

Whilst my first sea-water flotation experiments, carried out on
Keeling Atoll and in the Turks Islands, were limited in duration,
they established the great buoyancy of the fruits of both species of
Tournefortia, none of them sinking during a period of forty days in
the case of T. argentea and of sixty days in that of T. gnaphalodes.
In a subsequent experiment made in England four fruits of T. argentea
that had been gathered twenty-one months were placed in sea-
water, all of them floating and displaying sound seeds after a year's
immersion. In the same way I made a later experiment in England
on fruits of T. gnaphalodes collected twelve months before. All
remained afloat and retained sound seeds after six months in sea-
water. They were sown out, and after a couple of months several
germinated and produced healthy seedlings. The delay in the
subsequent germination conveys a warning against expecting quick
results when testing the germinative capacity of seeds after prolonged
flotation in sea- water. There was also delay in the case of the fruits
of T. argentea which had been forty days afloat in sea-water on
Keeling Atoll. Dr. Treub, Director of the Botanic Gardens of
Buitenzorg, Java, sowed seven of them in one of his houses, and
all germinated in the course of two months ( Journ. Vict. Inst. Lond.
1889).

However, the dispersal of the fruits of Tournefortia by currents
is not always so simple as it appears to be. In the case of T. gnapha-
lodes it was necessary to employ a good number of fruits in my
experiments, since about half of them had no seeds, the contracted
seed-cavities indicating their early failure. Another influence that
goes towards reducing the number of fruits effective for dispersal
is the tendency of the fallen fruits of this plant to germinate unsuc-
cessfully on the sand beneath the shrub, a matter already mentioned.
It is thus likely that a large number of the fruits swept off a beach
by the waves and carried off by the currents may be ineffective for
purposes of dispersal.

With reference to the distribution of Tournefortia gnaphalodes
in the ten islands of the Turks Group, it may be said that the plant
came under my notice on all of them except Cotton Cay ; but it is
highly probable that it occurs on that island also, as my examination
of it was incomplete. In the two largest islands of Grand Turk and
Salt Cay it grows in quantity, both on the edge of the beaches and
on the sand}^ belts in the rear. On Grand Turk it grows around the
greater portion of the island, and is especially abundant along the
length of the weather or east side. But it thrives almost as well
on the rocky surfaces of small cays, such as Penniston, Long, and
Pear Cays, where sandy beaches are either scanty or absent. Whilst
it grows over the surface of such small rocky cays, which are from fifty
to a hundred yards in width and from twenty-five to thirty-five feet
in height, it rarely strays far from the vicinity of the beach in the
larger islands, and does not usually climb far up their slopes. How-
ever, it grows on the sandy top of Round Cay, which, though forty-
five feet in height, is the smallest of the islands. In islands, like

250 PLANTS, SEEDS, AND CURRENTS

Pear Cay and Eastern Cay, which are exposed to the full force of the
strong winds, the main stem lies prone and roots in the sand, only the
primary branches rising erect into the air (see Note 3 of the Appendix).

From Mr. Lansing's methodical examination of the Florida sand-
keys west of Key West, we are able to form an idea of the relative
abundance of Tournefortia gnaphalodes in comparison with the other
plants, the flora being almost entirely littoral and in many respects
identical with the shore flora of the Turks Islands. Of the nineteen
keys described, those occupied alone by mangrove colonies being
excluded, nine possessed this plant, which, though nowhere abundant,
is evidently fairly well distributed over this region. Yet, although
better represented than Sccevola Plumieri, which was found on only
four of the keys, in no single key did it form a predominant feature
of the vegetation. In five cases it was either scanty or very scanty,
and in the other keys it grew in moderate amount.

From the data given by Grisebach, Harshberger, Millspaugh,
Urban, and others, it is evident that the currents have distributed
Tournefortia gnaphalodes all over the West Indian islands, both large
and small, from Cuba, Jamaica, and the Bahamas to Barbados
and St. Vincent. I have no information relating to its occurrence
on the mainland of South America; but its ability to establish
itself on the most isolated islands is indicated by its existence on
Grand Cayman and the Alacran Shoals (Millspaugh). Though most
characteristic of the vegetation bordering the sandy beaches, it is
frequently to be found on a rocky shore of calcareous formation.
It is a plant that prefers coasts fully exposed to wind and wave,
and I have shown in Note 3 of the Appendix how well it adapts its
growth to the wind-pressure. Dr. Millspaugh, who had an extensive
acquaintance with it in the West Indies, states that it prefers a
station " on the beach line facing the open sea " {Plant. Utow.).
In this respect it resembles T. argentea its sister species of the Pacific
islands, both plants on account of their hardy nature being amongst
the first shrubs to establish themselves on a newly formed coral-sand
key.

Some of the results of the foregoing comparison of these two
shore species of Tournefortia are tabulated in the table on p. 251.

ViGNA LUTEOLA, Bcuth.

In my volume on Plant Dispersal I deal with Vigna lutea, A. Gray,
a common strand species in the tropics of both hemispheres, but,
as it would appear, most characteristic of the Old World. I was
familiar with it amongst the beach plants of Hawaii and Fiji. Its
small seeds, 5 or 6 mm. long, were frequent in the beach-drift of those
groups, and also in the floating drift of Fijian rivers. Experiments
showed that they can float for months unharmed in sea- water.

Widely spread in the warm parts of the New World is a sister
species, Vigna luteola, Benth. In its littoral station, in its general
habit, and in the buoyancy of its seeds, its behaviour is similar to
the other species. It has a very wide distribution in the New World.
According to Hemsley and Grisebach, it ranges from Carolina and

MISCELLANEOUS PLANTS

251

Texas to Peru and Chile on the Paeific side and as far south as Buenos
Ay res on the Atlantic side ; and in the Old World, as we learn also
from Hemsley (Bot. Chall. Exped., II., 29) as well as from Oliver
(Flora of Tropical Africa, IT., 206), it is found on both coasts of Africa
and in Australia. It is widely dispersed in the West Indies. Grise-
bach gives Jamaica, Antigua, Dominica, and St. Vincent as its
homes. Millspaugh (Plant Utow., I., 53) gives Porto Rico, Jamaica
(Port Antonio), and the Cayman Islands. In Jamaica I noticed it
at Port Antonio, St. Anne's Bay, and at Black River. It is not

Tabitlated Results of the Comparison of T ournefortia GNARHALOBESy R. Br.,

AND T OURNEFORTIA ARGENTEA, Linn. f.

Tournefortia gnaphalodes

Tournefortia argentea

Main facts of
distribution.

American shores of the
tropical and subtropical At-
lantic, including the West
Indies, South Florida, and the
Bermudas.

Tropical, continental, and in-
sular shores of the Indian and
Pacific Oceans, excluding the
Pacific coast of America ; also
on coast of tropical West
Africa.

Fruit-characters.

Dry drupaceous fruit, about
7 mm., separating into two
hemispherical pyrenes, each
pyrene displaying a small
two-celled stone (a seed in
each cell) imbedded in a cork-
like exocarp.

Similar to the other species,
except that the fruit is rather
smaller.

Buoyancy of
fruits in sea-water.

Float for months with seeds
unharmed, none of them sink-
ing.

Float for months without
injury to the seed, none of
them sinking.

Cause of the
floating capacity.

The buoyancy is due to the
cork-like exocarp, the stone
having no independent float-
ing power.

The same as with the other
species.

Probable home
of the species be-
fore buoyancy was
acquired.

In the tropics of the New
World.

In the tropics of the Old
World.

Subsidiary dis-
persal agencies.

Birds, drift-wood and pum-
ice.

Birds, drift-wood and pum-
ice.

mentioned in Hart's " Herbarium List " for Trinidad ; but I found it
on the south coast of that island. It is also included in the Bermudian
flora.

Hemsley says that it frequents brackish marshes on the seashore,
and Grisebach states that it is common in Jamaica in this station.
At Port Antonio I found it thriving in wet places on the beach.
At St. Anne's Bay it grew on the beach ; and at Black River it was
scrambling over the reeds and other vegetation within the mouth
of the estuary. On Porto Rico, Millspaugh described it as " rising
free among high reeds and grasses " (Ihid.). In Trinidad I found

252 PLANTS, SEEDS, AND CURRENTS

it on the beach. In the delta of the Mississippi it grows in great
luxuriance, giving its character and name to the plant-association
that clothes the higher portions of the alluvial banks between the
" passes " or mouths of that river : here, clambering amongst the
canes of Phragmites communis it forms an almost impenetrable
thicket (Harshberger, Phyt. Survey, N. America, pp. 216, 444,
under Vigna glabra, a synonym).

The seeds of Vigna luteola, which are rather smaller than those
of V. Intea, float for a long time in sea- water. Some, which had been
seven weeks afloat in one of my experiments, germinated freely
afterwards. They help to form the smaller drift of beaches, as I
noticed at Trinidad. Amongst the floating drift of the estuary of
the Guayas River in Ecuador, I collected a number of sound seeds
of a species of Vigna, apparently those of V. luteola.

The cause of the floating capacity of the seeds of both Vigna lutea
and V. luteola lies in a large central cavity between the cotyledons,
the materials composing the seed having no independent buoyancy,
a matter dealt with for the first species in my previous book (p. 106).
The genus holds about fifty known species, spread over the warm
regions of the Old and New World ; and it would be important to
determine whether it follows the rule laid down in my earlier work,
that when a genus possesses both littoral and inland species only
the seeds or fruits of the shore species float. In the case of the
Hawaiian representatives of the genus the possibility was there
pointed out (p. 139) that the two endemic inland species were de-
rived from the coast species (F. lutea). The genus, it may be added,
offers many interesting problems for the consideration of the student
of distribution.

XlMENIA AIMERICANA, L.

The ^^Titer made the acquaintance of this shrub or tree amongst
the littoral plants of Fiji, where its means of dispersal were investi-
gated, the results being given in his previous work on the Pacific.
Like the species of Sccei ola and Cassytha that figure in the strand
floras all round the tropics, it can be dispersed in two ways, by birds
and by currents. Its drupaceous fruits are known to be distributed
by fruit-pigeons {Chall. Bot., L, 46); whilst the stones are able, as
I ascertained, to float in sea-water for months. But since the fruits
were rarely represented in the beach-drift, it was assumed that bird
agency has been predominant in the Pacific {Plant Dispersal, p. 113).

Although, as Hemsley observes (Chall. Bot., IV., 132), it is a mari-
time shrub throughout the tropics of both hemispheres, it may
extend inland — a behaviour which it most frequently exhibits in the
New World. It has been recorded from Tahiti, Samoa, Tonga,
Fiji, from the islands of the Western Pacific, from North Australia,
Malaya, both coasts of Africa, and both coasts of the New World.
Its usual place among the trees and shrubs lining the beaches of the
Old W^orld seems often to be abandoned, as just remarked, for an
inland station in the tropics of America. Though it is frequent
in the interior of South Florida, it has not established itself amongst
the characteristic littoral vegetation of the coasts or of the sand-keys.

MISCELLANEOUS PLANTS

253

Whilst it is a plant of the beach and of the dunes on the coasts of
Cuba (Harshberger, p. 673), it seems to be most characteristic of
inland districts in Jamaica, occurring, as we learn from the work
of Fawcett and Rendle, at heights of from 2000 to 3000 feet. See-
mann, however, observes that it is common on the sea-beach on the
Pacific side of the Panama Isthmus (Bot. Voy. H.M.S. Herald).
Whilst its range is said to cover the region between South Florida
and Buenos Ayres, its distribution seems to be fitful in the West
Indies, and I find no reference to it in my notebooks.

It would seem that in the New as in the Old World the fruit-
eating pigeons have taken a more active part in its dispersal than
the currents. Reference may here be made to the fact that this
is one of the plants that established themselves on Verlaten Island
after the complete destruction of its vegetation by the great eruption
of the neighbouring island of Krakatau in 1883. It was found there
by Ernst and his party in 1906 (Ernst's New Flora of Krakatau,
p. 37).

The distribution of the species of Ximenia, only five being known,
is suggestive of a genus that owes its representation in both the
New and the Old World to its original dispersion from a common
centre in high northern latitudes in an age when warm climatic
conditions prevailed in those regions. It seems difficult to look for
any other satisfactory explanation in the case of a genus which has
one species that is found round the tropical zone, a second confined
to Mexico, a third to Brazil, a fourth to South Africa, and a fifth
to New Caledonia. Yet alternative explanations are possible,
though not necessarily hostile to Dyer's hypothesis, even though we
cannot regard them with approval. Thus, one may regard all the
localised species as derivatives of the plant that ranges round the
tropical zone. From this point of view it might be supposed that
Ximenia americana, in dropping species, so to speak, in different
parts of its range, has played on a large scale the role of a highly
variable polymorphous species in the Pacific archipelagos. Here
a solitary species, the sole representative of its genus and ranging
over the tropical Pacific, becomes ultimately in each group of islands
the parent of a number of peculiar species, the same process being
also exemplified in the individual groups (Plant Dispersal, p. 333,
etc.). Nevertheless, such an explanation would not account for the
original occurrence of the parent species in the ocean-severed regions
of the tropics. Either we must regard it as having travelled from
its birthplace in the tropics around the globe through the agency
of birds and currents, or we must view it as having been originally
spread over the diverging land-masses of the globe from a common
centre in the north.

CHAPTER XI

THE GENERAL CHARACTERS AND GEOLOGICAL STRUCTURE OF THE

TURKS ISLANDS ^

The Turks Islands, well known on account of the salt industry
that has been long established there, are situated on one of the level
summits of a great submarine mountain range rising up from depths
of 2000 fathoms and over. The long and narrow bank on which the
ten islands lie is about thirty-seven miles long, as limited by the
100-fathom line. The depth of water covering the bank does not
generally exceed ten or eleven fathoms, and is often only three or
four fathoms; and so rapid is the submarine slope that, if limited
by the fifteen-fathom line, the bank would possess much the same
dimensions.

Geographically this group forms the south-eastern extreme of the
Bahamas. Botanically it belongs to the Bahamian region, and
geologically its structure is that of the same archipelago, the familiar
aeolian formation of the Bahamas here prevailing. The islands or
cays are low in elevation, none of them reaching 100 feet in height,
the highest (Eastern Cay) being ninety-six feet, whilst the lowest
(Long Cay and Penniston Cays) do not exceed thirty feet. They are
usually long and narrow, and vary in length from five and a half
miles in the case of Grand Turk to less than 200 yards in that of
Round Cay.

The general characters of this small group are those of the numerous
islands of the great archipelago of the Bahamas, all of which rise
from banks that are covered by a few fathoms of water. These
banks are the flat summits of a lofty range of submarine mountains
which terminate abruptly near the surface. Rising from the ocean's
depths of 2000 fathoms and more at the eastern end, the banks are
separated at the western extremity from the Florida coasts by
depths of about 400 fathoms. The 100-fathom line surrounds the
islands and reefs of the Little Bahama Bank, and a similar line
includes those of the Great Bahama Bank, with intervening depths
of less than 300 fathoms, the isolation of the banks increasing as we
go east, depths of 1000 to 2000 fathoms dividing those from which

^ This chapter was mainly written nearly four years ago, when the author was
only acquainted with the monograph of A. Agassiz on the Bahamas. Since it has
been in type he has enjoyed the privilege of communication with Dr. Vaughan, who
has recently investigated the western Bahamas. His conclusions are of great
importance ; but the writer has been obliged to deal with them in Note 39 of the
Appendix.

254

\30
12-

Turks Islands

{Adapted from Admiralty Chart 1266)

Heights in feet thus (40)
Soundings in fathoms thus 40,
When no bottom was found, thus ^fd

Scale of Sea Miles

707

765

367

140

^vJ^'t

Grand "nirkilWle^,^ TURKS ISLANDS

lesser Sand

Entrance to
Hawks Nest JncJtS'

(62) yrt/fli*^.*'* l^r* 7

d^mst<in <%'(30)a

,£ast

9

(96)

ijrjoo

8\

*^^ ./,^ r ^

810^^'^

A2j U

}120

903

* ; ^tfr<»<rfpr Sca^d fay (40)

i/

14:

617 'M.
180

..<4 .tesi « ^®\...^

16

-""•••...<*;./ 12 ■

MOUCHOIR
® BANK

77

Jcani.Bal4oIainewi Go. .tail?

STRUCTURE OF THE TURKS ISLANDS 255

the eastern islands rise. All the islands are of moderate elevation,
Cat Island displaying the greatest height of about 400 feet ; but their
average height would not amount to half this elevation, and large
areas of some islands are not removed many feet above the sea.

Whilst viewed orographically the Bahamian banks are connected
at their western end with the Florida region and project at their
eastern end into the ocean's depths, they present a similar relation
with the Greater Antilles. This connection becomes more and more
dissevered as we proceed from west to east, depths of rather under
300 fathoms dividing the Great Bahama Bank from the north coast
of Cuba, whilst depths of 2000 fathoms and over separate the eastern
banks, on which the Turks and Caicos Islands lie, from the north
coast of Hispaniola. Trending eastward from the Turks Bank is the
line of the Mouchoir, Silver, and Navidad Shoals, which are sur-
rounded on the north, east, and south sides by depths of 2000 to
3000 fathoms. On the north side of the Bahamian archipelago the
submarine slopes descend to depths of 2000 fathoms a few miles
from the shore.

Some curious considerations offer themselves when we reflect on
the present and past conditions of the Bahamas, of which the Turks
Islands form a part, considerations that have a bearing on the
origin of the geological structure and of the floral characters of the
whole region. It may be that in Miocene times, when the Florida
peninsula was under the waves, the Bahamas were the Laccadives
and the Maldives of the coral-reef region of the Atlantic. Dana in
his Corals and Coral Islands (p. 213) gives vent to a suspicion of this
kind ; but he did not follow it up, and contented himself with noting
the analogy between the eastern and western ranges of land on the
Great Bahama Bank and the opposite sides of the Maldive Group.
However, the coral reef makes a peremptory demand to be called
as a witness in this connection, and for this reason. Only in coral-
reef regions could we find the conditions that have produced an
archipelago, several hundred miles in length, consisting of relatively
low islands that are entirely composed of reef debris and calcareous
aeolian rocks. In a geographical sense the analogy with the above-
named archipelagos of atolls in the Indian Ocean is closer than
would at first appear. The Laccadives would represent the western
portion of the Bahamas, where the islands come into relation with
the adjacent continent, and the Maldives would stand for the free
oceanic eastern portion that protrudes into the ocean's depths.

In the Bahamas we have an archipelago possessing hundreds of
islands, large and small; and yet along its length of 600 miles and
more there is not an island that is more than 400 feet above the sea,
the majority of them not exceeding half this elevation. Several of
the eastern islands rise from banks that are the flattened tops of
submarine mountains starting up some 12,000 feet above the ocean's
floor. Yet there is relatively little difference in the elevation of the
islands, and we find this small range in height along the length of
the archipelago. We have here the anomaly that so exercised
Darwin's mind in the case of the lines of living atolls in the Indian
and Pacific Oceans ; that is, a lofty range of submarine mountains,

256 PLANTS, SEEDS, AND CURRENTS

rising from the ocean's depths, which along a length of several
hundred miles exhibit a line of peaks that in all cases end abruptly
at or near the ocean's surface. The implication is that atolls origin-
ally crowned the summits of these submerged peaks in Bahamian
seas, atolls long since overwhelmed by the shifting sand-dune, the
work of which is presented in the aeolian sandstone of our own day.
But, as in the line of atolls formed by the Laccadive and Maldive
archipelagos, there is a " continental " end, where the Bahamian
archipelago abuts on the adjacent continent, and an "oceanic" end,
where it projects into the ocean's depths.

The standpoint adopted with regard to the problems offered by the
Bahamas would, I think, largely depend on whether the investigator
was familiar with the western or continental " portion or with the
eastern or " oceanic "' portion. The points of view might differ
materially. Politically as well as geographically the western area
is by far the most important ; and from the time of Catesby, nearly
200 years ago, to that of A. Agassiz in our own day, the experience
of the west has largely coloured the views of the majority of investi-
gators. Agassiz, it is true, made a general examination of the
archipelago; but his acquaintance with the west principally deter-
mined his views. On the other hand, the present writer's experience
was limited to a three months' sojourn in the Turks Islands at the
extreme eastern end of the archipelago, during which period he made
a fairly detailed examination of all the islands of the little group.
He may thus claim to be an exponent of the " oceanic " standpoint.

Much mystery surrounds the history of the Bahamas. The view
that there are atolls buried beneath the aiolian deposits does not
involve any change of level, since the sand-dune could have effected
all that we see at present without the assistance of a movement of
upheaval. When, as with the Turks Islands Bank, the original
bank was long and narrow, the atoll form of reef would be replaced
by a reef of similar shape. But on a broad platform, like that pre-
sented by the neighbouring Caicos Bank, a typical atoll might have
been formed, of which we may discern the remains now in the broken
margin of islands and in the extensive flats in the interior of the
bank that are now covered by only a few feet of water. However
this may be, all that we see at present could have been produced at
the existing sea-level. Different periods of upheaval and subsidence
of the Bahamian area have been postulated by geologists and
zoologists; but, without entering into matters that are mainly
inferential, I will at once proceed to refer to the account of these
islands given by A. Agassiz in his Recoimaissance of the Bahamas
(Bull. Mus. Comp. Zool. Harvard, 1894), a work from the hand of one
of the foremost investigators of our time.

A. Agassiz on the Formation of the Bahamas. — After remark-
ing that the islands of the Bahamas are from end to end all of aeolian
origin, he thus proceeds —

" They were formed at a time when the banks up to the ten-fathom
line must have been one huge irregularly shaped mass of low land,
the coral sand beaches of which supplied the material that must
have built up the successive ranges of low hills which we still find in

STRUCTURE OF THE TURKS ISLANDS 257

New Providence, and which are so characteristic of all the ridges of
the islands of the group. After the formation of the islands came
an extensive gradual subsidence, which can be estimated at about
300 feet, and during this subsidence the sea has little by little worn
away the a:iolian hills, leaving only here and there narrow strips of
land in the shape of the present islands."

Before I proceed to give in detail the results of my observations
in the Turks Islands some discussion of the views of Agassiz is
necessary. He considers that the disintegration of the original land-
surface is still in progress; but this would be under present-day
conditions, which would be quite other than those which prevailed
when the land was being broken up during the movement of sub-
sidence, and could not safely be employed in illustration of it. In
this connection he regards the strips of land on the Caicos and Turks
Banks as representing the last stages in the process of destruction,
the original condition of those banks being exemplified in the neigh-
bouring large island of Great Inagua, where the whole area of the
bank is occupied by land ; whilst the intermediate stage is presented
in the island of Andros. Another point is that this investigator
lays no stress on the operation of reclaiming agencies at the present
time. Here and there a bight or a cove may have been filled in;
but the prevailing tendency in our own day, as in the past, is (he
holds) one of destruction. However, as he himself shows, a large
portion of the island of Grand Turk has been reclaimed by coral-
growth at the present sea-level; and in general terms he describes
the islands of the Turks Group as formed in part of aeolian rock and
in part of shore coral-rock.

Then again, when he describes the Bahamas as representing the
results of the breaking up, during a movement of subsidence amount-
ing to 300 feet, of one huge mass of low land, he could have had in
his mind only the western portion of the archipelago. The banks
from which the eastern islands rise must have been isolated through
the ages. So rapidly do they plunge down into the great depths
dividing them that an upheaval of 300 feet would add but little to
their size, and would be far from establishing any connection between
them.

Let us take the adjoining banks from which the Turks and Caicos
Islands rise. They are united under the sea by a " col " covered by
about 250 fathoms of water, and lying a few miles to the south of
them. This " col " is the head of a deep submarine valley, running
north between the two banks along their whole length, which is at
least about 1500 fathoms deep opposite Grand Turk and about 2000
fathoms where it debouches on the ocean's floor. A subsidence of
300 feet (fifty fathoms) could not have effected the separation of
these two banks, seeing that the " col " was some 1200 feet under
the sea before it commenced. Moreover, isolated as the two banks
are from each other, this " col " is in relatively shallow water as
compared with the ocean depths around them. The great hollow
that separates them on the south from Hispaniola is 2000 fathoms
and more in depth. Similar depths of 2000 fathoms isolate the
Caicos Bank from the neighbouring island of Mariguana, and prob-
s

258 PLANTS, SEEDS, AND CURRENTS

ably also from Great Inagua. To the north of the two banks lies
the open ocean with a depth of 2000 to 3000 fathoms.

No soundings in which bottom was obtained are given in the
Admiralty chart (1266) for the seas dividing the three great banks
stretching south-east from the Turks Islands, namely, Mouchoir,
Silver, and Navidad Banks; but it is not improbable that they are
connected by deeply submerged " necks." Except probably on the
Turks Island side these three great banks rise up from the ocean
depths around them. The trench separating them from Hispaniola
is 2000 fathoms deep, whilst to the north is the open sea, where
soundings of 3000 fathoms have been obtained. To the east this
line of banks plunges down in a few miles to depths of over 2000
fathoms, which increase as we go eastward some forty miles towards
the Brownson Deep, where depths of 4000 to 4500 fathoms occur.
From what has been said above it is apparent that the eastern
extremity of the Bahamian area, including the Caicos and Turks
Banks with the islands rising from them and the Mouchoir, Silver,
and Navidad Banks that carry no islands, has been isolated from the
rest of the region by deep-sea conditions through the ages. As we
proceed westward the connecting seas become shallower and the
banks and islands larger; but the process is gradual, and even
immediately west of the Caicos Bank depths of 1200 to 1800 fathoms
separate banks and their islands.

I come now to the reasons assigned by A. Agassiz for assuming a
subsidence of 300 feet. They are based on the existence of " ocean-
holes " in the banks. These holes have been sounded to a depth of
thirty-four fathoms (204 feet); and it is to be supposed that in
estimating the total depression at 300 feet he allowed for the depth
of water covering the banks. He considers that they were formed
in the aeolian rocks, before the subsidence, by the same agencies that
produce the present caverns, sinks, blow-holes, etc., in the aeolian
sandstone of the hills. We learn from his maps that these " ocean-
holes " may pierce the banks to a depth of 200 feet and may be 200
yards or so in width. I venture to think that this evidence in sup-
port of a depression of 300 feet is a little hypothetical. In any case,
the decision must lie with the student of land forms and submarine
contours, the interpretation of which has become an important
branch of geological science in recent years.

The subject of these " blue " or ocean " holes has evidently
received much attention from American geologists. Dr. Vaughan
has recently procured additional information concerning them in the
North-west Bahamas, and he writes that " on the assumption that
these holes were subaerially formed, parts of Andros must have once
stood 192 feet higher than now." Similar but smaller holes, as he
states, exist in the Miami coast region of Florida. They penetrate
to a depth of over thirty-five feet a rock floor of oolite lying ten feet
below low tide, and are regarded as " indicating the presence of
solution wells " in that formation {Year Book of the Carnegie Institu-
tion of Washington for 1914 and 1915, No. 13, pp. 227-33; No. 14,
p. 231).

This subject raises another important point. An implication of

STRUCTURE OF THE TURKS ISLANDS 259

the theory of Agassiz is that the foundations of the scoHan sandstone
would He far beneath the surfaee of the sea. I find no reference in
his pages to the exposure of any base-rock in this region, and his
views would expressly exclude the idea of the existence of a founda-
tion of " reef-rock " at or above the sea-level. In the case of the
same aiolian formation in the Bermudas, Professors Heilprin and
Rice lay stress on the exposure of a foundation of reef-rock; but
Agassiz rejects their interpretation. Naturally, if, as I hold, the
jEolian deposits of the Bahamas were formed with the sea at its
present level there would be a base-rock composed of coral-reef
debris ; and it ought to be exposed during the retreating tide, where
cliffs front the sea. But a little reflection will show that situations
favouring its exposure would be usually inaccessible on account of
the breakers and the rollers ever dashing against the base of the
sea-cliffs. Such an examination would be hazardous in the Turks
Islands, for the sea is rarely sufficiently quiet on the weather coasts
of the islands where these sea-cliffs exist. In those places where
the cliffs lie a little inland, being cut off from the sea by the growth
of a fringing reef, extensive beaches with the sand piled up against
the foot of the cliffs would effectually prevent observation. The
most favourable localities would exist where a line of cliff washed by
the waves abuts on a beach. Even these do not always permit one's
approach ; but I found such an accessible spot in the Turks Islands,
and there was exposed, underlying the geolian sandstone, a reef-rock
containing large fragments of corals.

There are two points connected with these seolian sandstones to
which A. Agassiz makes no allusion. The first is that this formation
seems to be peculiar to the Bahamian and Bermudian regions.
Calcareous sandstones, formed by the consolidation of wind-blown
sand derived from coral-reef beaches and composing entire islands,
are unknown in the great coral-reef regions of the Indian and Pacific
Oceans. The second point is concerned with the conditions under
which these aeolian rocks were formed. Their absence, more or less
complete, from other great coral-reef areas would seem to imply
that unusual conditions, mainly climatic, prevailed during their
formation in the Bahamas and in the Bermudas. Both these
matters are dealt with at the close of the chapter.

The Author's Observations on the Geological Characters
OF the Turks Islands. — The results are given here exactly in the
form in which they were written before the author had read the
memoir of A. Agassiz on the Bahamas. The remarks suggested by
the perusal of that work have since been intercalated. The sojourn
of the American naturalist in this group probably did not cover
more than a week or two ; but he seems to have visited all the islands,
including those that are most isolated, such as Eastern Cay and
Greater Sand Cay. Though few details are given by Agassiz, it will
be seen that the results obtained by the present writer are in general
agreement with his conclusion that the islands are formed in part of
^olian sandstone and in part of shore coral-rock. However, the
distinction has to be made between the work of the past and of the
present in describing the formation of these islands. Whilst the

260 PLANTS, SEEDS, AND CURRENTS

extensive low sandy tracts, overlying old reef-rock, belong to the
present, the " nuclei " of seolian sandstone, around which they have
been formed, belong to the past, a past when probably almost the
whole of the Turks Bank was occupied by land of ^olian formation,
four-fifths of which have disappeared at the hands of the marine
and aerial eroding agencies.

All the ten islands or cays are composed either entirely or in part
of the seolian sandstone, the gro"wth in size in later times by the
development of low land around " nuclei " of the aeolian rock being
chiefly characteristic of the larger islands.

The Molian Sandstone. — This is a white calcareous sandstone of
the Bahamian oolitic type. Whilst on the exposed surface the
materials are often cemented into a hard crust, which is some
inches thick and possesses an almost flinty fracture, they are usually
loosely compacted beneath, so that the rock readily breaks down
between the fingers. The crust, however, is generally broken up
into slabs, as explained below, thus exposing the less consolidated
rock which, readily disintegrating, has furnished much of the loose
sand that occurs on the surface of the interior of the larger islands.
It is as a semi-compacted sandstone that the rock typically presents
itself ; but in the smaller low flat cays it is the hard crust that attracts
most notice, and one might imagine that one was dealing in the
mass with a hard, honeycombed limestone, if the attention was
confined only to the surface characters. It is in the face of the line
of bluffs on the east side of Grand Turk and in the coast cliffs of the
other large cays that this formation is best exposed; but one may
find good exposures at times in the smallest of the islands when they
possess any elevation, as on Round Cay.

This formation sometimes offers itself in thick beds of loosely
compacted sandstone composed of usually well-rounded grains
varying from 0-5 to 1-5 mm. in size. At other times the rock is made
of finer materials, between 0-3 and 0-5 mm. in size and rather more
consolidated. Such finer sandstones often display a laminated
structure, the layers being usually horizontal; but they are occa-
sionally inclined, in which case cross-bedding may at times be
observed. The hard crust exhibits scattered grains in a compact
matrix, and has the appearance of a consolidated calcareous ooze;
but, as is shown below, it has a very different history. All these
rocks dissolve readily in acid, leaving scarcely any residue.

Nowhere did I find any marine shells or other marine remains in
the aeolian rocks. However, on the sandy slopes of Gibb Cay I
found gathered together on a ledge great numbers of old Bulimoid
shells of a large species of land-mollusc. Whether they had been
freed by the disintegration of the sandstone from which the loose
sand was derived, or whether they represented a molluscan fauna
that had subsisted on vegetation which had been destroyed by the
goats, I could not determine. The first explanation seems to be
most probable, since A. Agassiz (p. 20) remarks that land-shells
similar to those now living on the islands occur in the seolian rocks
of the Bahamas.

We come now to the consideration of the hard surface-crust of the

STRUCTURE OF THE TURKS ISLANDS 261

aeolian sandstone, a discussion that will lead up to the treatment of
the causes of the consolidation of the rock in the mass. The harden-
ing process of the crust extends to a depth varying usually from
three to twelve inches. When, as often happens on the lesser cays,
large level surfaces of the hard crust are fully exposed to the sun's
heat, the rock becomes fissured in all directions, and the ground
looks as if it had been irregularly paved. With the continuation
of the Assuring process and the constant widening of the cracks
through the weathering agencies, the ground is ultimately strewn
with slabs of all sizes that generally vary in thickness between three
and twelve inches and lie in confusion around. All over these
islands we find in the interior and even at the coast, both on level
ground and on the tops of the more barren ridges, this slabby broken
ground in all stages of disruption. The hard crust separates readily
in large slabs from the underlying loose sandstone. On Penniston
Cay, a low flat island only thirty feet in height, the hard surface
crust is in places so much honeycombed and broken up that walking
is difficult. In other places, again, we have large slabby undulating
surfaces only in the early stage of the disrupting process, and looking
more like the top of a lava flow. This hard crust of the a:olian
sandstone has often been described. Alluding to this sandstone,
A. Agassiz remarks that it is " covered with a hard ringing crust
when exposed to the action of the sea or the rains." In this con-
nection we can here appropriately introduce the fact that it is to
his celebrated father, L. Agassiz, that we are indebted for the clue
to the nature of the hardening process that affects the surface of
the rock.

The Observations of L. Agassiz on the Salt Key Bank. —
But the observations of the elder Agassiz, which were published
about half a century ago in the first volume of the Bulletin of the
Museum of Comparative Zoology, go further, since they also throw
light on the conditions under which the consolidation of the mass
of the formation takes place. They were made on the keys or low
islands of the Salt Key Bank, which lies between the Great Bahama
Bank and the coasts of Florida and Cuba. After describing the
oolitic rock (as he terms it) formed by the consolidation of the
calcareous sand of the high dunes gathered by the wind, he alludes
to its being very hard and to its ringing under the hammer, the
weathered surface being implied. But the clue is afforded in his
reference to thin layers of very hard compact limestone, alter-
nating with the oolitic beds, which have no doubt been formed in
the same manner as the coating of the pot-holes."

These pot-holes are described as of two kinds, those of recent and
those of ancient origin. The first, lying near the water's edge, are
" mostly clean excavations," being either empty or containing a
little loose sand or pebbles. The second, ordinarily beyond the
reach of the tides and the waves, have often been " graduafly filled
with materials identical with those of the older (oolitic) deposits."
They are " generally lined with coatings of solid, compact, and hard
limestone, varying from a thin layer to a deposit of several inches
in thickness. ... It is plain from their structure that these coatings

262

PLANTS, SEEDS, AND CURRENTS

are a sub-aerial formation, increasing: by the successive accumula-
tions of limestone particles left upon the older rock by the evapora-
tion of water thrown upon the Key when the ocean is so violently
agitated as to dash over the whole Key. Frequently the hollow of
these coated pot-holes is further filled with consolidated oolite; or
thin layers of fine-grained oolite alternate with a coat of compact
limestone, throughout the excavation, which has often been filled
in this way up to the general level of the surrounding surface. ..."
The structure and the mode of filling of these ancient pot-holes are,
as Agassiz goes on to say, distinctly exhibited in the cases of those
that have been partially cleared out by the action of storms.

The account of the keys of the Salt Key Bank is given in full by
Dana in his Corals and Coral Iskvids (1872 p. 213,). The elder
Agassiz supplies an illuminating description of the history of the
formation of these aeolian rocks on these islands. The bank, covered
by from four to six fathoms of w^ater, is formed of the " oolitic "
grains of coral materials mingled with broken shells. Its margin
is encircled in some places by rocky ridges and in others edged by
sand-dunes. " A close examination and comparison of the different
Keys show that these different formations are in fact linked together,
and represent various stages of the accumulation, consolidation, and
cementation of the same materials." That the aeolian rocks have
been formed by the consolidation of the sand-dunes, he has no
doubt. The sand composing them " must have been blown up by
the ^^dnd, and accumulated in the form of high dunes before it
became consolidated." This dune-sand is still loose, but, as on
Salt Key, it shows " here and there a tendency to incrustation at
the surface." Then in the case of another key, where the aeolian
sandstone prevails, he says : " It is evident that what is beginning
on Salt Key has here been completed." All this, it should be noted,
has been accomplished with the sea at its present level, a matter
that is dealt with again below. Different localities have their
individual lessons, and I may here remark that though sand-dunes
occur in places near the coasts of the larger islands of the Turks
Group, they very rarely exhibit a tendency to surface-consolidation.

The Basement of the ^Eolian Sandstone. — For reasons before
explained, underlying rocks of a character different from that of the
aeolian rock are rarely exposed. It has already been observed that
the claim made by Professors Heilprin and Rice for the existence of a
basement of old reef-rock in the Bermudas is disallowed by A. Agassiz,
who regards it as the effect of the action of the sea in cementing the
strata together and destroying their aeolian structure. But the
weightiest evidence against him is supplied by his father in the case
of the islands of the Salt Key Bank. Their foundation is not aeolian
sandstone, but " a conglomeration of coarser oolitic grains, rounded
fragments of corals, or broken shells, and even larger pieces of a
variety of corals and conchs, all the species being those now found
living on the Bank." Stratification is displayed, the beds dipping
towards the sea at an angle of about seven degrees. This founda-
tion never rises above the level of high- water. It is, as the present
writer will show, but a coarse kind of the " beach-rock " that is

STRUCTURE OF THE TURKS ISLANDS 263

exposed between the tide-marks on the sandy islets of coral-reef
regions all round the tropies, and forms the basement of the islet.
Upon this foundation are heaped up by the waves, as is described
by L. Agassiz, masses of sand, broken shells, and fragments of
corals, which in their turn are covered by the finer sand driven by
the wind and forming sand-dunes. He does not refer to any ex-
posure of an actual contact of the asolian rock with its foundations ;
but we may infer that they would be the materials heaped up by the
waves, but more or less consolidated and cemented, and passing
downward below the high-water level into the basement rock,
similarly composed of sand, broken shells, and coral debris, that
constitutes the foundation of the islands.

It was only in one locality in the Turks Islands that I found a
good contact-exposure of the rocks underlying the a^olian sandstone.
This was on the east coast of Greater Sand Cay near its southern
end. Here, about two or three feet above the high-water level, the
a^olian rock sometimes passed down into a coral-rag, composed of
large fragments of massive corals imbedded in a matrix of compacted
coarse sand, and at other times into an ordinary coarse beach sand-
rock such as is described below.

"Beach sand-rock " came under my notice in different islands of
the Turks Group, as on Grand Turk and Salt Cay. It is character-
istic of low coral islands all over the tropical Pacific, and doubtless
is common enough in the Bahamas. It is well described by Dana
in his Corals and Coral Islands (1872, pp. 152, 184), and I have dealt
with it in my Geology of the Solomon Islands (1887, p. 84). It is a very
coarse white sand-rock, and is stratified, the beds dipping seaward
with the slope of the beach at an angle usually of seven or eight
degrees. It is composed of coral and shell debris; but many
characters distinguish it from the aeolian sandstone or drift sand-rock,
notably the larger proportion of coral debris, the coarseness of the
constituents, and their great irregularity in size. Sometimes the
materials forming the beach sand-rock are imperfectly consolidated.
At others they are firmly cemented into a hard rock with a metallic
ring; and when, as is not infrequent, large fragments of corals and
dead shells are enclosed in the hard matrix it might be termed a
coral-rag, though reef-rock would perhaps be a more appropriate
name. The typical rock is exposed between the tide-marks. But
it is a formation that is only exposed by the removal of the overlying
loose sands by the waves. Wherever exposed, it is always in process
of destruction through the action of the sea. I have never seen it
in process of formation. The conditions under which the stratifica-
tion and consolidation take place are obscure. Evidently, whether
as sand-rock or reef-rock, it forms the platform on which islands and
islets are thrown up by the waves ; and it would be on such a
foundation that the subsequently produced seolian deposits would
be based.

The upshot of the foregoing remarks would appear to be this. If
there has been an extensive subsidence of 300 feet in the Bahamian
region since the formation of the aeolian sandstone, as is assumed by
A. Agassiz, the foundations of the seolian rock ought to lie far beneath

264 PLANTS, SEEDS, AND CURRENTS

the waves. As far as the Turks Islands suppHed direct evidence on
this point, it was to the effect that the a^oUan rocks passed downward
into consoHdated reef debris, consisting of coarse sand, dead shells,
and coral fragments, which had been thrown up on reef-rock at the
present sea-level. The same inference is to be drawn from the
observations of L. Agassiz on the islands of the Salt Key Bank.

The Evidence supplied by Charts of Recent Changes in
Level in the Bahamas. — Fortunately this matter has received
considerable attention in one way or another. Looking at the
evidence supplied by the examination of old maps, particularly that
obtained by Mr. Tiilinghast which is mentioned below, and having
regard to the unimportant changes that occurred between the
careful survey of 1834 and the time of his visit in 1893, A. Agassiz
concludes that " we are warranted in assuming that the configura-
tion of the Bahamas, as we now know them, does not differ materially
from that of the F<^* de los Liicayos as they were first discovered by
Columbus." From this we may infer that during a period of 400
years no great change has occurred in the relations between land and
sea in this region.

Mr. Tiilinghast carried out his investigations with the idea that
" an examination of old maps " might reveal a change in the con-
dition of the Mouchoir, Silver, and Xavidad Banks since the time of
the discovery of the Bahamas " which might be of importance in the
disputed question of the landfall of Columbus." As a result he
formed the conclusion, after examining a large number of old charts
going back to the beginning of the sixteenth century, that " they
throw more light on the condition of the cartography of the West
Indies than on any physical change among the islands " (see yotes
on the Historical Hydrography of the Handkerchief Shoal {Mouchoir
Bank) in the Bahamas, in the " Library of Harvard University,
Bibliographical Contributions," No. 14, 1881).

In this connection A. Agassiz lays stress on the difficulties sur-
rounding such investigations, and notably the rarity of actual sur-
veys of these regions. He points out (p. i4) that in the chart of the
first survey of these three banks at the south-east end of the Bahamas,
that of Count de Chastenet-Puysegur (1784-7), only shoals and
banks are dra^\Ti. This is interesting as sho^^'ing that the three
banks (Mouchoir, Silver, Navidad) bore no islands then as they bear
no island now. Their stationary condition during the last 200
years is also indicated by the fact that their shoals and rocks were
as dangerous to the navigator in the early part of the eighteenth
century as they are now. The site of a wTcck, named " Plate
Wreck," is marked in some of the old charts on one or other of
these three banks. Thus it is shown in one of the maps given by
Catesbv in his work on the natural history of Carolina, Florida, and
the Bahamas (Vol. I., 1731).

In the British Museum library I came upon an old chart of the
Turks Islands, which is not included in Tiilinghast' s extensive list
of the early maps of this region. It describes itself as constructed
from " a survey made in 1753 by the sloops VAigle and V Emeraude
by order of the French Governor of Hispaniola with improvements

STRUCTURE OF THE TURKS ISLANDS 265

from observations made in 1770 in the Sir Edward Hawkey King's
Schooner." Further details are given in Note 32 of the Appendix;
but I may say here that it represents the results of a regular survey,
the three main positions being fixed by astronomical observations,
the error in longitude being about forty minutes and the errors in
latitude not exceeding two miles. But, as will be noticed below,
when discussing the effects of the reclaiming process in these islands,
the period for comparison is very limited, since the latest Admiralty
chart of this group is mainly based on the survey of 1830. It is,
however, permissible to infer on grounds given in the Note that
there has been extensive shoaling between the islands since the
French survey, though the depths on the open bank clear of the
islands experienced but slight change in the interval between the
middle of the eighteenth and the middle of the nineteenth century.
Lesser Sand Cay, a sandy islet lying between Cotton Cay and Grand
Turk, on which plants obtain at times a scanty hold, evidently did
not exist at the time of the French survey.

The Degradation of the ^Eolian Sandstone in the Turks
Islands. — Just as L. Agassiz in the case of the geolian rocks of the
islands of the Salt Key Bank lays stress on the extensive disintegra-
tion they are experiencing at the hands of the atmospheric and
marine agencies, so we may lay emphasis on the same process of
destruction in the Turks Islands. If Nature busied herself in pro-
ducing these deposits ages ago, she is not doing so now. There is
nothing about these formations that is modern. For ages they have
been exposed to great degradation ; but, as we shall see. Nature by
setting up a reclaiming process is now doing her best to save the
pieces. In those localities where there is no protecting beach, as in
the case of the smaller rocky cays and of some of the headlands of
the larger islands, the full force of the breakers of the open ocean
is spent in the destruction of the seolian sandstone. Long narrow
rocky islands, such as Long Cay and Penniston Cay, where there is
no protection against the breakers, have already been cleft through
near their extremities. Toney Rock, which lies near Eastern Cay
and receives the whole brunt of the breakers, represents the last
stage in the process of destruction. When a beach protects the
coast, the atmospheric agencies are active in degrading the cliff-
faces that once were buffeted by the waves. The bluffs, so con-
spicuous on the eastern side of Grand Turk, are from this cause in
full retreat landwards.

The Modern Process of Reclamation of Land from the Sea
IN THE Turks Islands. — As already observed, A. Agassiz lays no
stress on reclaiming agencies in the Bahamas. L. Agassiz, who
rightly includes the Salt Key Bank in the Bahamian region, refers
to the " very instructive combination of the phenomena of building
and destruction " in its shoals and keys. In the Turks Islands
there exists, side by side with the process of degradation of the
original land-surface of geolian rock, a process of renovation that
will ultimately prevail. It is unfortunate that a comparison of the
old French chart of 1753 with that in present use covers too short a
period to be of much service to us. The Admiralty chart (No. 1441)

266 PLANTS, SEEDS, AND CURRENTS

of the Turks Islands is based on Captain Owen's survey of 1830,
with additions to 1845 and corrections to 1898; whilst the French
chart is emended from observations made in 1770 in an English
survey ; so that the period for comparison is limited to sixty years.
However, as will be shown below, the changes that can be estab-
lished are all on the side of " gain." The reclaiming process is
indicated : —

(a) By the shoali?ig of the Bank. — Whether we referred to the
French chart or to the later chart, we should be equally correct in
saying that the bank from which the Turks Islands rise is covered
by from ten to eleven fathoms of water in the deeper parts. But
more than eighty years have elapsed since the last survey, and it is
evident that the whole bank is shoaling through the growth of coral
and the accumulation of reef debris. Sandbanks are forming in
the shallows and are endeavouring to give rise to new islands. One
such islet, known as Lesser Sand Cay, lies half-way between Grand
Turk and Cotton Cay. Though well exposed at low-water, it is
ever shifting its site and changing its form. At times vegetation,
derived from drift seeds, begins to appear on its surface ; but before
long this is washed away by the waves. When I knew it in the early
part of 1911, it was a bare bank of sand not 100 yards in length.
Yet in time a permanent islet will be established, and a century
hence it will be well stocked with littoral plants.

(b) By the throwing up of Protective Beaches and Sandbanks around
and between the nuclei of jEolian Sandstone. — Yet Nature has other
ways of reclaiming land from the sea on the bank. After the waves
have been battering for ages one of these islands of seolian sand-
stone, she often sets herself to work to save the pieces through the
growth of corals and the heaping up of sand and other reef debris.
Let us take the case of Greater Sand Cay, which is about one and a
half miles in length and elevated some forty feet above the sea.
We can read its history as we approach it from the northward. In
the distance it appears as a group of four islets. But as we get
nearer low connecting strips of land rise above the horizon, and we
discover that the four islets, as they seemed, form the hummocks,
or low, mound-like hills, of a single island. The hummocks are
made of the a^olian sandstone, and the low necks that unite them
are banks of sand. Here it is evident that a long strip of land of
aeolian rock was first broken up by the action of the sea. But in
later times, whilst the waves were wearing away the islets, the water
was shoaling around. Ultimately the energy of the waves was
chiefly occupied in throwing up protecting beaches and in joining
the islets by sandbanks. In this way the remains of the original
island have been preserved, and doubtless the present island will
continue to increase in extent. The process of joining up the islets
has evidently been in operation in relatively recent times. In the
French chart (1753-70) the northern third is represented as separated
from the rest of the island by a channel 250 or 300 yards wide and
two feet deep. The extensive shoal or patch of reef that runs north
from this island seems to be in much the same condition now as it
was a century and a half ago, except that there appears to have

STRUCTURE OF THE TURKS ISLANDS 267

been a northward extension of a few hundred yards since that
date.

The original length of Greater Sand Cay is indicated by the shoal,
from which some rocky points protrude a few feet above the sea,
that stretches nearly two miles to the north of the island. Originally
there was a long narrow island, quite three miles in length, of which
the northern half has been swept away; whilst the southern was
broken up into fragments that have since been joined together by
the reclaiming agency of the waves. This process of reclamation
will continue, and a low sandy tract will occupy the place of the
shoal extending to the north ; while the island will add to its breadth
on its western side. The process of preserving the remains of the
original island is, however, not yet completed at the southern
extremity, where the geolian rocks form a steep promontory that is
still exposed to the full force of the breakers in the open ocean.

The opposing forces of destruction and reclamation are in opera-
tion all over the Turks Group, Where the tendency to protective-
beach formation is slight, as with Long Cay, we see a long strip of
aeolian rock being broken into fragments by the waves. We see in
Pear Cay and in Eastern Cay two islands that were once one, but
are now separated by a rock-studded channel, half a mile in width,
that has been the scene of more than one of the shipwrecks in this
locality. Pear Cay seems likely to disappear altogether in the
course of time. Eastern Cay, however, has since doubled its extent
by the formation of a broad sandy tract on its west side ; and while
the breakers are ever pounding away against the precipitous cliffs
of jeolian sandstone on the eastern side, the waves are ever adding
to its area on the west.

The Composite Structure of the Larger Islands of the
Turks Group. — In the larger islands the process is a little more
complex. The extension of sandy flats from different " nuclei " of
seolian rock here led to the enclosure of mangrove-fringed lagoons,
which are now in various stages of silting up and of being cut off from
the sea. Thus the lower levels of these islands are sandy where
they have been heaped up by the waves, and loamy where they
have been reclaimed by the silting of the lagoon.

We will begin with Grand Turk, an island about five and a half
miles long and averaging rather over a mile in breadth. A ridge of
seolian sandstone runs along the eastern border of the island, attain-
ing a height of seventy feet along much of its length, the greatest
elevation being seventy-five feet. In addition there are low hills
and rising ground of lesser elevation in the north-west, south-west,
and centre of the island. But the greater portion of its surface is
raised only a few feet above the sea, being no higher than the waves
could have elevated it. Two large lagoons, the North and South
Creeks, originally penetrated nearly to the centre of the island.
Both were lined by a dense growth of mangroves, which are now
almost entirely confined to the South Creek; and both occupied
depressions that were below the sea-level.

The ridge and lesser elevations of Grand Turk once formed islands
of seolian sandstone representing a large land-mass of the same

268 PLANTS, SEEDS, AND CURRENTS

formation that had been broken up by the waves. The growth of
coral and the heaping up of reef debris led to the development of
extensive sandy flats which reconnected the islands and enclosed the
lagoons. The reclaiming agency of the mangroves regained large
loamy tracts at the borders of the lagoons ; whilst the sandy tracts
were ever increasing by accretion through the materials heaped up
by the waves. One of these methods of reclamation is well displayed
at the southern end of the island, which, according to the residents,
has extended considerably in recent years through the formation of
successive lines of sandbanks. It is strange that the significance of
the great recovery of land from the sea that is involved in the
building-up of Grand Turk did not present itself to A. Agassiz,
since he states that whilst the eastern border of the island is formed
by " a narrow ridge of feolian hills," the breadth of the island in its
centre consists of " flats " formed by the recent growth of shore
coral-rock Indeed, everything that is of importance to man on
Grand Turk, and particularly its salt-pan industry, is due to the fact
that it has been largely reclaimed from the sea.

A word may be said about the two lagoons of Grand Turk. The
South Creek was doubtless originally far more patent than it is at
present. It is covered during the higher part of the tide; but at
low-water it is exposed, and extensive mud-flats monopolise its
area. Salt-rakers have been busy here for over two centuries, and
have evidently largely transformed this part of the interior of the
island. It is likely that the " salinas " or salt-ponds represent the
original extension of the South Creek into the centre of the length
of Grand Turk. The North Creek is a clear sheet of water about
one and three-quarter miles long and 600 to 700 yards broad. It is
credited with a depth of four fathoms in the Admiralty chart, and
is now nearly silted up at its mouth. These matters are also referred
to in the remarks on the topography of the island in Chapter XII.
The delineation of the two creeks in the Admiralty chart (No. 1441),
which dates back to 1830 and 1845, is puzzling. The details of the
interior of the island are given in a large-scale map (three inches to
a mile) based on a survey executed in 1902-4 by J. F. Osborn (Colonial
Surveyor) and on the Admiralty chart just mentioned. The depths
of the sea around, that are given in this map, are merely taken from
the soundings in the chart.

Salt Cay reproduces all the features of Grand Turk, and it has had
the same history Though about three miles in length and about
one and a half miles in breadth, its surface is for the most part
elevated only a few feet above the sea, the low ridges and hummocks
of fEolian sandstone, that rise in places to heights of sixty feet, having
served as " nuclei " for the growth of extensive low flats of coral and
reef debris. Here also there were lagoons communicating with the
sea, their shores lined by mangroves that have been almost entirely
cleared by the labours of the salt-rakers, who, in making their
" salinas," have transformed the interior of the island. Apart from
the salt-ponds and the shallow ponds scattered about, a large creek,
still communicating with the sea on the south-east coast and bor-
dered in 1911 in one or two places by mangroves, recalls the original

STRUCTURE OF THE TURKS ISLANDS 269

condition of the island when large lagoons occupied its interior.
Whilst a region of sand-dunes lies behind the beach at the north end
of the island, illustrating the constructive action of the waves and
of the winds, extensive bare rocky surfaces in the interior represent
the work of the coral reef. The same features are presented by
Cotton Cay. Here again islets of seolian sandstone, now existing as
elevations, thirty to forty feet high, at its two extremities, have
been joined by the reclaiming agencies of the waves and of coral-
reef growth ; but the lagoons have long since been cut off from the
sea, and are now represented by shallow ponds in the centre of the
island.

No Recent Change of Level in the Turks Islands. — Of
changes in level, whether of elevation or of subsidence, I found no
evidence in this region. No old erosion lines came under my notice,
except in one or two places where it was apparent that they had
been merely cut off from the sea by the intervention of a beach or of
a reef-flat. That the level of the sea has remained much the same
for a long period is indicated by the circumstance that the platform
of reef-rock and ordinary beach-sandstone, on which the acolian
sandstone reposes, has been formed with the sea at its existing
level.

Probable Destruction in Great Part of the Original
Islands of the Turks Group. — There must have been great
destruction of the original islands of seolian sandstone before the
modern process of reclamation was made possible by the shoaling
of the great bank from which the present islands rise. The low hills
and ridges of the larger islands and the small rocky cays are but the
scanty remains of what may have been two or three large islands of
seolian rock that occupied almost all the bank. At a uniform depth
of nine or ten fathoms the bank extends seven or eight miles eastward
of Eastern and Pear Cays, and then plunges down into the depths.
All this submerged area was once covered by land of seolian forma-
tion. The same may be said of the two long tongues that extend
north and south from the opposite extremities of the group at a
depth of about ten fathoms for about seven miles in each case. The
same is also true of the inter-island tracts of shallower water. All
this land has disappeared.

The same has been inferred by A. Agassiz for the whole
Bahamian Region. — All the questions raised by the consideration
of the Turks Islands are issues raised in connection with the seolian
rocks of the Bahamas as a whole. The original much greater extent
of the land-surface of seolian rocks, which has been postulated by
me in the case of the Turks Islands, was assumed twenty years ago
by A. Agassiz for the whole of the Bahamian archipelago. Before
the last subsidence of 300 feet, which, as he infers, affected the whole
region (a point on which the present writer, as already shown, is not
in agreement with him), the present banks were occupied, as he
holds, by " one huge irregularly shaped mass of low land." How-
ever, as I have pointed out, several of the eastern banks are now
separated by passages 1000 to 2000 fathoms deep. We cannot,
therefore, postulate for that period a continuous land-surface over

270 PLANTS, SEEDS, AND CURRENTS

the area occupied by the present archipelago ; but, judging from the
size of the larger banks, several of the islands must have been as
large as an ordinary English county. In addition to the original
islands of seolian formation, of which fragments still remain, there
were several others, of which no trace now remains beyond the
submerged bank that has been generally worn down to the lower
limit of breaker-action, except where it displays a few " rocks awash."
Probably none of the islands exceeded 500 feet in elevation, and
their average height must have been less than half this amount.
Their entire surfaces were covered by wind-blown sand; and, in
fact, their entire thickness was the work of the drifting dune. The
compacted seolian formations, of which they are now composed from
top to bottom, plainly tell the story of the building up of these
islands; and there is little to indicate that there was any covering
of vegetation of any extent.

The History of the Bahamas is the History of the Sand-
dune. — These large islands were built up under the sway of the
shifting sand-dune, and must have offered a spectacle not to be
found on the same scale in any insular territory in the present era,
not even in the great coral-reef regions of the Indian and Pacific
Oceans, These unusual formations, unusual in the sense just
defined, required unusual conditions; and we have now to ask
ourselves what exceptional conditions offered the opportunity for
the dominion of the dune.

They must have been the conditions that prevail on the sea-board
of those great continental masses where the dune holds its sway.
At the present time the most insignificant sandbank in coral seas
becomes the home of the mangrove, and numerous other plants
establish themselves as the bank emerges from the waves. We do
not read in our own day of islands in coral seas that are swept clean
by ever-shifting sand-dunes. The Turks Islands lie in a region of
storms and gales ; and if ever strong winds could restore the original
sterility of these islands we might look for their work here. Yet,
what do we find ? In an island like Salt Cay, where the sand-dunes
are well developed in places, they make but little effort to overrun
the surface. The conditions of the present are confessedly not
those of the past ; and in what, we may ask, has been the change ?

Before answering this question, let us picture to ourselves the con-
ditions that once prevailed over insular land-areas, fifty to a hundred
miles across, where the drifting sands reigned supreme, conditions
that, as above remarked, are now only found on the sea-board of
great continents. The coast regions of Peru are the home of the
shifting sand-hill, or " medano," so graphically described by Dr. von
Tschudi in his Travels in Peru (London, 1847, p. 243). A fine light
yellow drift-sand here covers hill and dale, and when driven by
violent winds the medanos pass rapidly over the sandy plains. The
smaller ones, though moving quickly forward before the larger ones,
are soon overtaken and overwhelmed by them. At one time they
cover the plain. At another they move across its breadth in rows.
The whole face of the landscape may in this manner be transformed
in a few days, and the traveller who had previously lost his way

STRUCTURE OF THE TURKS ISLANDS 271

amidst a labyrinth of sand-hills may on his return traverse a clean-
swept plain where not a single medano obstructs his view. Though
the sand is not formed of calcareous materials, but is derived from
the disintegration of andesitic rocks, the lesson will be the same.

In February 1904 I spent several days in examining the medanos
of the Ancon coast-region north of Callao. Since the details are
given in Note 34 of the Appendix, I will confine myself here to a
few general remarks. Sand covers the broad plains and the lower
hill-slopes and completely hides the crests of hill-spurs, 400 feet in
height, as they descend to the coast. At the time of my visit these
crescentic mounds, usually six to ten feet high and twenty-five to
thirty feet across, formed a line, or rather a column, of two or three
irregularly abreast traversing a sandy waste of hill and plain for a
distance of from four to five miles, and crossing ridges and spurs
300 or 400 feet in height. I watched them as they came into being
near the beach and as they died away miles inland a few hundred
feet up the slopes of the main range in their fruitless endeavour to
scale the mountains. I spent hours in watching them dribbling
over the sharp crest of a mountain-spur that descends to the coast
immediately south of Ancon. They had reached the crest after a
climb of about 350 feet from the beach below, and as I sat on the
ridge-top observing them, they peppered my face with their finer
sand with each fresh gust of wind. The sand usually formed a con-
tinuous slide during the descent of the steeper northern slopes of
the ridge, the medanos shaping again when the sand reached the
plain; but where there was a gentler gradient they re-fojmed half-
way down the slopes. During my sojourn the prevailing winds were
light, and, as measured by me, the medanos moved forward only a
few inches a day ; but before a fresh wind they would advance yards
daily. Before a gale they would move rapidly across the plains, and
a strong wind blowing athwart their line of advance would in the
course of a day or two level them with the ground. Von Tschudi
also describes medanos with immovable bases formed around blocks
of rocks that are scattered about the plain. While the sand is heaped
up by the wind on one side, 'it descends on the other; and there is
nothing permanent about this type of medano but its site and its
conical shape. The moving medano, however, is the great distributor
of sand over the arid wastes of the sea-board of Peru. Sterility
reigned over the sand-covered plains and hill-slopes of Ancon. Only
occasionally one came upon patches of a little bromeliaceous
"tumble-weed" {Tillandsia), which, however, became more frequent
as the plains approached the foot of the mountains.

But, to return to the large islands of the Bahamas, as they origin-
ally were, covered with and built up by drifting sand, with little or
no vegetation to compete with the dominion of the sand-dune, the
conditions of the present are confessedly not those of the past, and
in what, we may again ask, has been the change ? I would suggest
with some diffidence that the climatic regime which now prevails
on the sea-borders of North Chile and Peru once existed in the
Bahamian region. Just as the cold waters of the Humboldt or
Peruvian Current determine the relative sterility of that continental

272 PLANTS, SEEDS, AND CURRENTS

sea-border by causing the precipitation of the moisture carried by
the prevalent south-west winds before they reach the land, so in
the past a cold current from the north swept along the northern
shores of the Bahamas and cut off the moisture carried by the north-
east trade-winds. From this point of view the seolian formation of
the Bahamas represents the New World's response in ancient times
to the influences producing arid sea-borders in w^arm latitudes (cold
currents and drying winds), but in a region of calcareous sands and
under insular conditions, an association of circumstances not repeated
on the same scale in any other part of the globe.

At present, as Commander Campbell Hepworth informs me, the
influence of the Labrador or Arctic Current as a surface-stream may
be traced along the shores of the United States as far as the Florida
Straits during most of the year. But how little do we know of the
arrangement of the surface-currents in earlier times ; and what, we
may also ask, would be the behaviour of the Arctic Current if
the great Equatorial Current, from which the Gulf Stream takes its
rise, flowed in mass, as it probably once did, across the site of the
present Panama Isthmus into the Pacific? The effect of the
emergence of this isthmus was the birth of the Gulf Stream, and the
effect of the Gulf Stream was the dissipation to a large extent in
tropical latitudes of the cold current from the north, so that the
Bahamian region would no longer come under its influence. Before
the change we had here the same association of aridity with a cold
current that exists on the sea-border of Peru and also on the sea-
borders of South California and North Mexico, where the moisture-
laden \Wnds, by passing over the cool waters of the Californian
Current, become drying wdnds when striking the continent and
produce the aridity of its sea-border. In the cases of the South
African Current and the w^est coast of South Africa and of the West
Australian Current and Western Australia we seem to have the
same association of conditions. [For further particulars of the
writer's views on the influence of the Humboldt Current on the
climate of the Pacific border of South x\merica reference should be
made to pp. 490-6 and 500 of his work on Plant Dispersal (1905)].

I may add that the association of the birth of the Gulf Stream
with the elevation of the Panama Isthmus is by no means a new
idea. The various rearrangements of the land-areas in the tropics
of the New World adopted by some botanists, zoologists and geolo-
gists often involve the shutting off of the Gulf Stream from the
North Atlantic. However much Darwin's great authority may have
weighted the scale against them, the " extensionists " have obtained
results in these tropical regions that call for a re-valuation of their
testimony.

The Standpoint of the Extensionists. — Reference may again
be made to the relations between the western Bahamas and
the adjacent islands of the Greater Antilles. Though depths of 2000
fathoms divide the eastern Bahamas from Hispaniola, much shallower
submarine connections exist between the Great Bahama Bank and
Cuba, and the possibility of a Cuban land-connection in times that
are past cannot be ignored. This leads one to refer to an alternative

STRUCTURE OF THE TURKS ISLANDS 273

explanation of things Bahamian," which, although based mainly on
zoological evidence, makes a serious claim on some of the geological
testimony that the " anti-extensionist " is wont to regard as peculiarly
his own.

The remarkable similarity in geological structure between the
Bermudas and the Bahamas is rightly emphasised by Scharff in his
Distribution and Origin of Life in America (1911, p. 185); and he is
justified in doing so, since the peculiar aeolian formation of these two
regions cannot be matched on the same scale in any insular region of
the globe. Should the same formation exist in Florida, the point
would acquire yet more importance. Laying stress on the zoological
argument that we are not concerned here with land-areas stocked
with " waifs and strays," but with ancient land-surfaces possessing
faunas often peculiar in their character, he advocates the hypothesis
that in Tertiary times the Bahamas and the Bermudas were included
in a land-area that joined together the Greater Antilles and was
connected with Florida (p. 186, and maps facing pp. 280, 294).

He points out (pp. 288-9) that although displaying affinities with
neighbouring regions, the Bahamas possess reptilian, amphibian and
molluscan faunas that are often largely their own. In this connection
Dr. Scharff could have also summoned to his aid the witness of the
plants. In the tropical Pacific, low islands, like those of the Bahamas,
would have been stocked through the agencies of birds and currents
with cosmopolitan and wide-ranging plants, and would have dis-
played little or no endemic element. On the other hand, the plants
of the Bahamas, as shown in Chapter XII., exhibit a marked Bahamian
impress ; and present characters that could only have been developed
during ages of isolation from other regions.

Note added August 2, 1916. — It will be shown in one of the last
notes of the Appendix that according to Dr. Vaughan and other
American geologists the similarity in geological structure between
the Bermudas and the Bahamas extends to the aeolian origin and
calcareous character of the deposits, but not to their mechanical
condition. A reply will there be made to the query concerning the
occurrence of this formation in Florida.

Summary

1. The low islands of the Turks Group, which belong geographic-
ally and botanically to the Bahamas, possess the geological features
so characteristic of that archipelago. They are composed in their
higher parts of aeolian sandstone, which is made of consolidated
calcareous drift-sand, and in their lower parts of coral-reef debris
thrown up under the existing conditions of sea-level. They possess
all the other general characters of the Bahamian Islands, which are
situated on banks that at the eastern extremity of the archipelago
rise from the ocean's depths and at the western end have shallower
connections with the North American continent and the island of
Cuba.

2. It is pointed out that only in coral-reef regions could we look
for the conditions that have produced a great archipelago with such

T

274 PLANTS, SEEDS, AND CURRENTS

uniformity in characters as found in the Bahamas; and it is urged
that the coral atoll makes a peremptory demand to be called as a
witness in this connection. It is suggested that the Bahamas were
in ages past the Laccadives and Maldives of the Atlantic. The
implication is that atolls originally crowned the summits of the
ranges of submarine mountains that are now represented by the
banks of the Bahamian seas, atolls long since overwhelmed by the
shifting sand-dune, the work of which is presented in the a^olian
sandstone of our own day. But, as in the linear grouping of atolls,
formed by the Laccadive and Maldive archipelagos, there is a " con-
tinental " end, where the Bahamian archipelago abuts on the adjacent
continent, and an " oceanic " end, where it projects into the ocean's
depths; and it is hinted that the standpoint adopted concerning
Bahamian problems largely depends on whether the investigator
was familiar with the continental or the oceanic portion (pp. 255-6).

3. Then follows a discussion of the views of Alexander Agassiz
on the formation of the Bahamas. The present writer's detailed
examination of the Turks Islands, during a sojourn of three months
in the group, enables him to approach the problems from the
"oceanic" standpoint; but, although at one with the eminent
American investigator as regards the leading structural features of
the group, he ventures to differ from him on some points of inter-
pretation. Thus, there can be little doubt that the existing Bahamas
are the remains of great tracts of low land of asolian formation that
have been in great part destroyed by the waves; but the writer
holds that the degradation occurred under the present conditions of
sea-level, and not during a subsidence of 300 feet as is assumed by
Agassiz. Then, again, the writer emphasises the great work of the
reclaiming agencies under present conditions, a matter on which
Agassiz lays little stress. Amongst other incidental points of differ-
ence are objections that he does not attach sufficient importance to
the isolation of the eastern islands by the ocean's depths, and that
the foundations of the aeolian formation lie near the existing sea-
level, and not far beneath the waves as is implied by his subsidence
hypothesis (pp. 256-9).

4. The author then gives the results of his observations on the
Turks Islands. The formation of the geolian sandstone is first
discussed, and the absence of marine remains is pointed out. In
this connection the results obtained by Louis Agassiz on the Salt
Key Bank are utilised. It is remarked that if Nature busied herself
ages since in producing the seolian rocks, she is now activeh^ engaged
in their destruction. Yet there is a process of reclamation at work
that will ultimately prevail, and new land has been, and is being,
formed around the remnants of the early islands. Disconnected
islets of aeolian rock, that are the fragments of a large island, have
been, and are being, joined together again into one island by the
growi;h of coral reefs and the formation of sandbanks. In this
manner the destructive action of the waves has often been stayed ;
and in the larger islands, while the more elevated " nuclei " of geolian
sandstone belong to the past, the low tracts of land that have been
formed around them belong to the present (pp. 259-262).

STRUCTURE OF THE TURKS ISLANDS 275

5. The question of the foundations of the acolian rock is then
dealt with, and the reply is that in the Turks Islands the acolian
sandstone passes down into consolidated reef debris, consisting of
coarse sand, dead shells, and coral fragments, which have been
thrown up on reef rock under the existing conditions of sea-level
(pp. 262-4).

6. Whilst discussing the modern process of reclamation in the
Turks Group, the structure of the islands is treated in detail ; and it
is shown that in the case of the larger islands, where lagoons have
been usually enclosed during the development of the new land, the
mangroves have been an important reclaiming agency (pp. 265-9).

7. The comparison of old and recent charts of the Turks Islands,
and of the Bahamas generally, does not often yield definite results;
but we may quote the conclusion of Alexander Agassiz, who paid
considerable attention to the matter, that the configuration of the
Bahamas has not been materially changed since their discovery by
Columbus, a conclusion that involves the implication that during a
period of 400 years no great change has occurred in the relations
between land and sea in this region (pp. 264-5).

8. All the questions raised by the consideration of the Turks
Islands are issues raised in connection with the Bahamas as a whole.
The original much greater extent of the land of acolian origin, which
is postulated by the author in the case of the Turks Islands, was
assumed twenty years ago by A. Agassiz for the whole Bahamian
region. Although we cannot assume that in distant ages a con-
tinuous land-surface occupied the area of the existing archipelago,
it is probable that several of the islands were as large as an average
English county and that their maximum elevation did not exceed
500 feet. They were completely covered by wind-blown sand, and
in fact their entire thickness was the work of the drifting dune,
there being little to indicate that there was any covering of vegetation
of any extent (pp. 269-270).

9. The history of the Bahamas is the history of the sand-dune.
The original islands must have offered a spectacle not to be found
on the same scale in any insular territory in the present era, not
even in the great coral-reef regions of the Indian and Pacific Oceans.
These unusual formations require unusual conditions, and the author
looks for them in the conditions that prevail on the sea-board of a
great continent where the dune holds its sway. The conditions of the
present in the Bahamian region are confessedly not those of the past ;
and in what, we may ask, has been the change (pp. 270-1) ?

10. Before answering this question, the author describes the sand-
wastes on the sea-board of Peru, where the shifting sand-hill reigns
supreme, and here he draws in part on his own experiences. He then
replies to the query above put, and suggests that just as the cold
waters of the Peruvian Current determine the aridity of the sea-
boards of North Chile and Peru, so in ancient times a southward
extension of the Arctic or Labrador Current would have produced
similar effects on the Bahamas (pp. 271-2).

11. Not to be ignored, however, is the view of the " extensionist "
school based on zoological evidence that the Bahamas and the

276 PLANTS, SEEDS, AND CURRENTS

Bermudas were in later Tertiary times included in a land-area that
extended to Florida and united the Greater Antilles. It indicates
that the last word has not been said in this matter (pp. 272-3).

12. Some conclusions arising from the recent work of American
geologists in the western Bahamas with additional remarks on the
question of the " ocean-holes " will be found in one of the last notes
of the Appendix.

LIST OF SOME OF THE WORKS QUOTED IN THIS CHAPTER

Aqassiz, a., a ReconDaissance of the Bahamas, Bull. Mus. Comp. Zool. : Harvard,
Vol. XXVI., 1894.

Agassiz, L., The Bahamas and Salt Key Bank, Bull. Mus. Comp. Zool., Vol. I.
Quoted at length by Dana in the work below named.

Dana, J. D., Corals and Coral Islands, 1872.

TiLLiNGHAST, W. H., Notes on the Historical Hydrography of the Handkerchief
Shoal (Mouchoir Carre) in the Bahamas, Library of Harvard University, Biblio-
graphical Contributions, No. 14, 1881.

Vaughan, T. W., Geological Investigations in South Florida and the Bahamas, Year
Book of the Carnegie Institution of Washington, Nos. 13 and 14, 1914, 1915.

Watkins, F. H., Turks and Caicos Islands, Report on the Salt Industry, Colonial
Reports — Miscellaneous, No. 56, 1908.

Old Chart of Turks Islands, from a survey made in 1753 by the sloops UAigle
and U Emeraude, by order of the French Governor of Hispaniola, with improve-
ments from observations made in 1770 in the Sir Edward Hawke, King's
Schooner : Laurie and Whittle, 53, Fleet Street, London, 1794.

CHAPTER XII

THE FLORA OF THE TURKS ISLANDS

We come now to an account of the flora of the Turks Islands.
The vegetation is generally sparse and may be described as " scrub,"
the soil being sandy and loamy and containing usually but little
humus. Different " cultivations " have been from time to time
carried on in the larger cays, especially on Grand Turk. But the
cultivated plants are few that will thrive in a sandy and often saline
soil, and, except for the clearances of the mangroves bordering the
lagoons and creeks in the construction of salt-pans, the botanist
will not find great difficulty in restoring much of the indigenous
flora of the large inhabited islands. In this he will be assisted by
the examination of the smaller uninhabited cays, and it is to these
smaller islands that my remarks will at first apply. Though goats
have been allowed to run wild on most of them at one time and another,
this practice had been largely discontinued at the time of my visit
in 1911. Their presence might account for small-seeded weeds like
Portulaca oleracea, etc., and might explain to some extent the scarcity
of fleshy beach plants like Sccevola plumieri on the lesser cays ;
but otherwise I should not imagine that through their agency the
original features of the flora, as presented in the smaller islands,
have been much obscured.

In an extract from the Annual Register of 1764 given by Com-
missioner Watkins in his report on the history of the salt industry
of these islands, we read that they are " sandy and barren with very
little, if any, fresh- water, without any vegetables except low shrubs,
or any animals except lizards, guanas, and land-crabs." Though
this reference was made more than a century after the Bermudian
salt-rakers began to visit the group, it was not until about 1678 that
they commenced systematic salt-raking during their annual sojourns
from March to November. It is a testimony to the obdurate nature
of the soil and to the difficulty of Nature's task in stocking these
islands with plants that so little has been effected since they were
first occupied by Europeans. Of course, in the larger inhabited
islands of Grand Turk and Salt Cay man has done something to
alleviate these conditions. But still their soil is not fit for raising
much else than sweet potatoes, guinea corn, and plants that thrive
in poor ground. For their fruits and vegetables the Turks Islanders
are almost entirely dependent on outside supplies. Yet, notwith-
standing the provision of government-ponds and tanks to hold the
rain-water, great inconvenience is often experienced during the dry

277

278 PLANTS, SEEDS, AND CURRENTS

hot season. In the not infrequent droughts cattle die in numbers,
and the gardens of the inhabitants lose most of their plants.

My principal object being to study the process of stocking the
small islands of these seas with plants, I was content to largely
limit my observations to such an inquiry. But it was also necessary
to obtain some acquaintance with the more extensive flora of the
largest island (Grand Turk) ; and though there are gaps in my
knowledge of its plants my remarks will, I trust, enable the reader
to form some idea of the peculiarities of its flora and of the general
facies of the vegetation. Dr. Millspaugh, who studied the plants
of this group with the eye of a systematist of great experience in
these regions, will be able to give a far more authoritative and com-
plete account. I looked at matters not with the discriminative
eye of the systematist, but from the standpoint of dispersal. This
position was rendered comparatively easy in the case of the plants
of the smaller cays, since they were largely stocked with wide-
spread strand plants that had long been familiar to me in tropical
regions.

The flora of the smaller cays is, as I have just said, chiefly a strand
flora. Characteristic West Indian littoral plants have often taken
charge of these small islands. In my description I will begin with
the smallest uninhabited cays that are formed almost exclusively
of seolian sandstone with but little beach or fore-shore. Next I
will take those larger in size, where low-lying, littoral tracts have been
added to the nucleus of geolian rocks, and will then pass on to the
large inhabited islands where man has exercised a greater disturbing
influence.

Pear Cay, which derived its name from the abundance of Prickly
Pear, is, according to the chart, about forty feet high and about
600 yards long. It is entirely formed of seolian rock; and, since it
possesses scarcely any beach, landing is not practicable when the
sea is rough. Much of the lower levels are strewn with sand supplied
by the disintegration of the sandstone, and here flourish Tournefortia
gnaphalodes, Siiriana maritima, Ipomcea pes-caprcE, Sesuvium portu-
lacastrum, and Corchorus hirsutus with a little Heliotropium curas-
savicum. I have referred in Note 3 of the Appendix to the manner
in which the species of Tournefortia, Suriana, and Corchorus adapt
themselves to the wind-pressure in this wind-swept cay, and I need
not particularise it here. On the upper portion there is little or
no sand and the rocky ground is almost exclusively occupied by
Ipomoea tuba, which largely conceals the broken slabs of sandstone
that lie about. In addition there was a Cyperus (C. hrunneust)^
which is common on all the small cays.

The Cactuses of the genus Opuntia, that occur here and on most
of the small cays and larger islands, are not differentiated in my
description. They form a feature of all the islands, and include
two common species, Opuntia tuna, the Prickly Pear, which is the
most frequent, and another with very long spines, locally known
as " Dildo," perhaps 0. triacantha, Haw.

Penniston Cay is a long flat strip of seolian sandstone, twenty-
five or thirty feet high. According to the Admiralty chart it would

THE FLORA OF THE TURKS ISLANDS 279

be about 800 yards long and a cable (200 yards) broad; but these
dimensions appear to me rather excessive. Its surface, which is
largely of bare rock, much honeycombed in some places and slabby
in others, is scantily vegetated. Having no beach worth mentioning
it receives the full brunt of the breakers, which have forced a passage
near its southern end where there is a natural arch. In rough
weather the seas deposit drift in the middle of its breadth. The
principal plants growing on it were Tournefortia gnaphalodes, Borri-
chia arborescens, Suriana maritima, Portulaca oleracea, Sesuvium
(two species), and a little Euphorbia buxifolia. On the lee side in
its southern portion there was a large patch of Opuntia, where Frigate-
birds were nesting in numbers.

Long Cay, like Penniston Cay, is a long and narrow flat strip of
seolian sandstone, raised twenty-five or thirty feet above the sea
and possessing one or two small beaches. It, however, receives the
full force of the breakers on its north-eastern side, and portions of
the original island now form islets at its extremities. As delineated
in the Admiralty chart its length would be about a mile and its
maximum breadth about 400 yards. However, I paced its width
in the broadest portion and did not make it much over 120 yards.
The surface is mainly of bare rock, covered, however, with sand
thinly in places.

Though much of its area had no covering of vegetation there
were considerable portions occupied by plants, especially on the lee
or south-western side, where there were extensive thickets, four
to six feet high, of the Seven-year Apple {Genipa clusiifolia), both in
fruit and in flower, mingled in places at the seaward margin with
Coccoloba uvifera. Next in frequency, growing semi-prostrate,
or clambering over the rocks, was a variety of Conocarpus erectus.
This is probably the form " procumbens " of Jacquin; but its
occurrence is chiefly limited to the weather or eastern extremity
of the island, to which the epithet " wind-swept " fitly applies; and
doubtless it is a station variety. Millspaugh found this form in the
Bermudas and on the coasts of Yucatan, and describes it in his
Plantce XJtowance (Field Columb. Mus. publ.). Borrichia arborescens
should also be reckoned as one of the most frequent of the plants
on this cay. Most of the common beach plants of these islands are
here represented, sometimes on the rocky portions, sometimes on
the sandy parts, such as Tournefortia gnaphalodes, Suriana maritima,
Ipomoea pes-caprce, Euphorbia buxifolia, Sesuvium portulacastrum,
etc. But Sccevola plumieri, which never came under my notice
on these small wind-swept cays, was not observed. Where a thin
covering of sand lies on the rock, the surface is almost carpeted with
Ambrosia crithmifolia associated with Cyperus brunneus. Near the
north-west end of the island Rhachicallis rupestris forms an extensive
patch of scrub one and a half to two feet in height. We learn from
Dr. Millspaugh (Prcenunc. Baham.) that this plant grows on maritime
rocks throughout the Bahamas and is " often the only vegetation
on many of the sea-washed islets."

We now pass from our description of the small rocky cays of seolian
sandstone possessing but little beach, and swept over a large portion

280 PLANTS, SEEDS, AND CURRENTS

of their surfaces by the sea in stormy weather, to the other small
uninhabited cays where the waves have thrown up more or less
extensive tracts of low-lying land fronted by beaches around a nucleus
of seolian sandstone. Here the strand plants that mainly stock these
small cays find congenial conditions on the sandy tracts behind the
beaches as well as on the seolian rocks of the higher levels. The
cays concerned include Eastern Cay, Greater Sand Cay, and Gibb
Cay, with Round Cay adjacent to it. Both as regards the stage in the
history of island formation and as concerns the conditions for plant
growth, they present an intermediate state between the small rocky
cays above described and the large inhabited islands to be sub-
sequently noticed. Here, as in Eastern Cay, the Turk's-head Cactus
(Melocactus communis) first appears, which is, or was, more at home
in the large islands. Here also, as in Gibb Cay, are found plants,
like the Burnt-bush {Euphorbia vaginulata) and Phyllanthus, that
abound on the large cays, as on Grand Turk.

Eastern Cay, as delineated in the chart, is about 1800 yards
long and has a maximum breadth of nearly 800 yards. On its north-
west side there is a broad sandy plain elevated a few feet above the
sea and running back between 400 and 500 yards to a stony ridge,
which attains an elevation of ninety- six feet and forms the backbone
of the island. Near the ridge the sandy plain gradually rises until
it reaches half-way up its slopes. Characteristic littoral plants
such as Tournefortia gnaphalodes, Euphorbia buxifolia, Ipomcea
pes-capra3, Sesuvium portulacastrum, Portulaca oleracea, and Borrichia
arhorescens grow at the border of the sandy beaches and on the ground
in their rear on both sides of the island. Apart from the plants
growing on the beaches the three most conspicuous features of the
vegetation of the island are (1) the abundance of Ambrosia crithmifolia
which covers the sandy plains and the lower sandy slopes on both
sides of the island with a dense carpet, (2) the frequency of Borrichia
arhorescens which mainly occupies the upper stony slopes, (3) the
prevalence of the Turk's-head Cactus {Melocactus communis), which,
though growing on the lower sandy slopes is most abundant in the
higher part of the island.

Cor chorus hirsutus is also common on the lower levels, growing
semi-prostrate on the sandy plains and associated in places with
Sesuvium. I noticed two or three fair-sized colonies of Ipomcea
tuba on the stony ground fifty or sixty feet above the sea. Cactuses
of the Opuntia type are common in the island, especially at and near
the summit. During my two visits I failed to find either Suriana
maritima or Genipa clusiifolia or Sccevola plumieri.

Gibb Cay, which is about 700 yards long, 200 yards broad, and
about sixty feet high, is almost surrounded by beaches, and has sand
strewn nearly all over its surface. Much of this sand is evidently
derived from the disintegration of the seolian sandstone which is more
friable than usual. The beach plants, which include Tournefortia
gnaphalodes, Sccevola plumieri, Suriana maritima, Conocarpus erectus.
Euphorbia buxifolia, Sesuvium portulacastrum, Ipomoea pes-caprce,
and the tall reed-grass, Uniola paniculata, extend with the usual
exception of the first named some distance up the slopes and reach

THE FLORA OF THE TURKS ISLANDS 281

often the higher levels. Leaving the beach behind we find Ipomoea
tuba growing nearly all over the undulating sandy summit, but
with numerous associates, sometimes Ipomoea pes-caprce. Ambrosia
crithmifolia and Sesuvium, at other times Phyllanthus epiphyllanthus.
Euphorbia vaginulata^ and Borrichia arborescens. The steep sandy
slopes are preferred by Sccevola plumieri. The Cyperus of the other
smaller cays also occurs, and I noticed an amarantaccous herb by
the beach. Goats and other animals have often been kept on this
island, and no doubt have affected the relative prevalence of the
different plants.

Round Cay is an islet lying about two cables or 400 yards from
Gibb Cay, of which it doubtless originally formed a part. It is
composed of the same friable aeolian sandstone, the disintegration
of which has supplied the sand that covers its surface. Its length
is about 150 yards or so, and its height forty- five or fifty feet. On
its flat summit thrive Tournefortia gnaphalodes, Sesuvium portulacas-
trum, and Euphorbia vaginulata, with a little Euphorbia buxifolia
and Portulaca oleracea. Cyperacece and grasses are common.

Greater Sand Cay, the most isolated island of the Turks Group,
is of especial interest to the student of the dispersal of plants in this
region. In sailing amongst the other islands one is in more or less
protected waters, but to accomplish the six and a half miles that
separate this island from Salt Cay the open ocean has to be traversed.
As a result one may have to wait for days and weeks before suitable
weather presents itself for reaching it, and on arrival it is not always
easy to land, whilst there is always a risk of being detained there
for some days by bad weather. The author spent two days on the
island. Dr. Millspaugh, who visited it a few weeks afterwards,
had difficulty in landing, the boat being turned over on top of him.
It would seem that we were amongst the first to investigate its
flora. This island is the first to catch the drift from the large West
Indian islands to the southward and eastward, and quantities of
seeds and fruits are stranded on the beach on its eastern side. Isolated
as it is, the disturbing influence of man and animals cannot be excluded.
Fishing-parties make a sojourn of a week or two, once or twice
during most summers. The small sailing craft of these seas anchor
occasionally on its west side to procure firewood, etc. Goats, again,
have been kept on the island, one or two being still there when I
visited it in March 1911.

The island is about one and a half miles long, 500 or 600 yards in
maximum breadth, and forty or fifty feet high. It is principally
made up of two main masses of geolian sandstone, connected by a
low neck of sand raised ten to fifteen feet above the usual high-
water level, but breached by the sea during the hurricanes. Each
of these principal portions is again subdivided, the two parts being
connected by a low sandy neck which is also breached in stormy
weather. During hurricanes the three necks are washed clean by
the breakers and largely stripped of their plants. At such times the
four nuclei of aeolian sandstone are isolated by the waves. Greater
Sand Cay is in truth one of the most wind-swept and sea-swept
islands of these regions, and it is exposed to the whole force of

282 PLANTS, SEEDS, AND CURRENTS

the breakers of the open ocean. Plants with difficulty establish
themselves on the beaches and on the necks, being liable to be swept
away in the storms. When they take refuge on the more elevated
portions of the island they are exposed to the violence of the hurri-
canes. Numbers of dead prostrated trunks of Suriana maritima
lay on the surface over the island during my visit, the victims mainly
of the last hurricane two or three years before.

Yet, with the exception of the low connecting sandy tracts, where
plant growth is scanty or almost absent, the surface is fairly well
vegetated. Owing mainly to the extensive disintegration of the
aeolian sandstone the surface of the more elevated portions is largely
covered with sand which is not less than seven or eight feet in depth
in places, and thus affords a good burrowing ground for the large
iguanas which abound. But the vegetation is what is termed of
the scrub kind. If we were to give a brief description of the plant-
arrangement we should say that the sandy soil is carpeted with
Ambrosia crithmifolia, Cyperi, and coarse creeping grasses {Cenchrus
echinatus^ etc.), whilst clumps of Suriana maritima and thickets of
Genipa clusiifolia frequently dot the surface. Borrichia arhorescens
also grows in numerous colonies on the sandy portions and as indi-
vidual plants where the ground is rocky, as on the southern headland.
Cactuses of the Opuntia type abound, but the Turk's-head Cactus
did not come under my observation.

All the above-named plants come down to the beach in places;
but the most characteristic beach plants are Tournefortia gnaphalodes
and Euphorbia buxifolia, species that seem able to hold their own
on the most exposed beaches in these islands. Other typical beach
plants such as Sccevola plumieri, Ipomoea pes-caprce, and Cakile
lanceolata appear to be not so well adapted in this respect. The
two first-named species were only represented by a few young plants
growing amidst the beach- drift and a little above it on the east
side of the principal isthmus. Of Cakile lanceolata I only found
a solitary clump in the same locality. When the seas break across
the low sandy necks during heavy weather most of the beach plants
that have obtained a temporary footing are washed away. Sesuvium
portulacastrum, a plant that is usually characteristic of beaches in
this group, only presented itself in a solitary patch on the eastern
beach. TJniola paniculata was scantily established on the lee or
western side of the island.

Cotton Cay. — Coming to the larger inhabited islands I will first
allude to Cotton Cay. There is a house on the island, but it is not
permanently occupied. However, sheep roam over most of its area,
and " cultivations " of different kinds have been from time to time
established and abandoned. I was not therefore disposed to take a
special interest in this Cay, and limited my examination to a traverse
across its centre and to a visit to the wind-swept eastern extremity
where the original vegetation promised to be least disturbed. The
island is about one and one-third miles long, 700 yards broad, and
about forty feet high in the " rises " of aeolian sandstone. But much
of its area is low, the surface being in places rocky and around the
two small central lagoons loamy and sandy. These lagoons are

THE FLORA OF THE TURKS ISLANDS 283

merely shallow ponds, which seem to have shrunk considerably in
modern times.

Conocarpus erectus was by far the most frequent constituent of
the bush in the interior of the island, and the Turk's-head Cactus
(Melocactus communis) was there not uncommon. Batis maritima
and Salicornia ambigua covered the muddy borders of one of the
lagoons that I passed near. On the beach on the south side were
observed Suriana maritima, Borrichia arborescenSy Ambrosia crithmi-
folia, and Ipomoea pes-caprce. On the rocky eastern extremity
were dense thickets of Coccoloba uvifera, the plants, owing to the
exposure to the strong trade-winds, growing semi-prostrate or low
and straggling. Here also Phyllanthus was common, and a few
specimens of Genipa clusiifolia found shelter from the wind in the
Coccoloba thickets.

Salt Cay, the second largest island, is triangular in form, about
three miles long and about one and one-third mile in greatest breadth.
It reproduces the physical features of Grand Turk. With the
exception of an elevated ridge of seolian rock, sixty feet in height,
near its northern border and an isolated hill of the same height
and composition towards its centre, most of it is raised only a few
feet above the sea; and in the areas occupied by several lagoons
and ponds, now shut off from the sea, its level must be below that
of the ocean. There are extensive beaches backed by sand-dunes on
the north, but bare rocky surfaces prevail over most of the rest of
the island except around the lagoons where the ground is loamy or
sandy. The salt industry has been pursued here with greater
energy than in Grand Turk, and no doubt the establishment of
salt-pans has quite changed the character of the vegetation in the
interior. The mangroves have been nearly banished ; but in places
around a large creek that communicates with the sea on the south-
east side Rhizophora mangle, Avicennia nitida, and Laguncularia
racemosa still survive, with extensive Salicornia colonies on the
bordering mud-flats.

Strand plants exist in profusion on the north and north-east
sides of the island, both at the borders of the beaches and on the
sandy dunes behind. Here flourish Suriana maritima, Tournefortia
gnaphalodes, Conocarpus erectus, Euphorbia buxifolia. Ambrosia
crithmifolia, and Ipomoea pes-caprce. Sccevola plumieri is scanty
in the island, but I found a fairly extensive colony on the beach
near the southern point. A solitary patch of Canavalia obtusifolia
was observed in the middle of the east coast. In the interior
occur plants characteristic of Grand Turk, such as the Burnt-bush
{Euphorbia vaginulata), Phyllanthus, etc.

Grand Turk. — The flora of Grand Turk, the largest island of
this small group, was first systematically examined by J. A. Hjalmars^
son, who spent a fortnight there in 1858, as I learned from Dr.
Millspaugh's manuscript, on his return from a botanical expedition
in Haiti. Various new species from the interior of this island were
described by Grisebach from Hjalmarsson's collections in his book
on the West Indian flora. Their number has been increased in later
years through the investigations of American botanists; but most

284 PLANTS, SEEDS, AND CURRENTS

of them exist on the adjacent islands of the Caicos Group and of
the two Inaguas; and I should imagine that the south-eastern
extremity of the Bahamian archipelago, consisting of the Turks,
Caicos, and Inagua islands, will prove to be a subdivision of the
floral region of the Bahamas. For years botanists from the United
States have worked this region, and an authoritative discussion
from the pens of Britton, Millspaugh, and others is to be expected,
if it has not already been published.

Generally speaking the flora of Grand Turk may be regarded as
displaying a Bahamian impress in its interior and a West Indian
impress at the coast. In other words, we can distinguish between
the inland plants that give character to the larger islands of the group
as a part of the Bahamian floral region and the strand plants, often
monopolising the smaller cays, that are not only widely spread in
the tropics of the New World, but are in not a few cases dispersed
over the shores of the warm regions of the globe. Whilst the system-
atist will be mainly attracted by the Bahamian facies and by the
more specialised local features of the flora, the student of dispersal
will be mainly interested in the plants of the strand. If the group
consisted only of the small wind-swept and sea-swept cays a few
hundred yards in length, its flora would have been almost entirely
littoral and its general facies would be West Indian. It is the non-
littoral vegetation of a large cay like Grand Turk that gives it its
Bahamian impress and its still more localised characteristics.

The topography of Grand Turk is also described in the chapter
on the geology of the group. Here I will deal with it afresh, since it
is necessary to bring into prominence features of more special interest
in connection with the flora. The island is about five-and-a-half
miles long and one to one-and-a-half miles broad, and attains a
maximum height of about seventy-flve feet. But much of its area,
especially in the southern half, is raised only a few feet above the
sea; and there are extensive portions below the sea-level that are
occupied by the salt-ponds and the creeks which represent lagoons
that once penetrated to the heart of the island.

Two creeks communicating with the sea penetrate the north and
south portions of the island. Both of them were doubtless at one
time well lined by mangroves, which, however, have been largely
cleared away from the North Creek, w^hilst in the South Creek they
are still well displayed. North Creek, though nearly silted up at
its mouth, is a clear sheet of water, about one-and-three-quarter
miles long and 600 yards wide. South Creek is much smaller; but
doubtless it originally extended much farther into the island, as
indicated by the " Great Salina " and other salt-ponds which reach
to the centre of the island's length. The dams and other works
carried out in connection with the salt industry have greatly changed
the surface-conditions of the central part of Grand Turk; but it
seems probable that originally South Creek extended as a chain
of lagoons to the Town Pond in the middle of the island, and that
the two creeks were only separated at their heads by a neck, not
over a quarter of a mile broad, which is now represented by the
low ridge dividing the Town Pond from the head of North Creek.

THE FLORA OF THE TURKS ISLANDS 285

Perhaps the most singular surface-feature of Grand Turk is the
ridge of low hills of seolian sandstone, usually elevated fifty or sixty
feet above the sea, that runs along the eastern border, completely
obscuring, as the Rev. J. H. Pusey remarks in his handbook of the
group, the eastern coast from the town or western shore. There
are, however, other elevated portions or rises," as in the north-
west, south-west, and central districts of the island.

The ground is occupied by open scrub all over the island, except
in the parts where old or present attempts at cultivation have exer-
cised disturbing influences, or where cattle have introduced new
plants when brought to the island. Much of the surface, however,
still illustrates the original condition of the open scrub vegetation
that clothed it at the time of the first occupation by Europeans.
The soil is loamy and sandy in the flats or lower levels, sandy on the
gentle slopes of the hills, and rocky on the crests of the hills and on
their steeper sides. The glaring whiteness of the sandy and loamy
surface of the plains is often but partially relieved by the scrub
that grows upon it. The soil is calcareous all over the island, and
the proportion of humus is usually small.

The Vegetation of Grand Turk. — I will deal in the first place
with the plants of the sandy plains, then with those of the rocky
upland districts and of other rocky localities, and lastly with the
strand vegetation.

1. The Plants of the Sandy Plains. — The scrub vegetation of
the sandy plains and of the gentler hill-slopes in the interior of the
island extends to the summit of the hills when the surface is sandy.
Euphorbiaceous and Composite shrubs, with bushes of Lantana
involucrata, and a pretty heath-like rubiaceous shrub, Borrera
thymifolia, often form the greater part of the scrub. The Com-
posite plants include Baccharis dioica and, as I was informed by
Dr. Millspaugh, species of Pluchea. Amongst the Euphorbiacece
the Burnt-bush (Euphorbia vaginulata) is the most conspicuous;
but Croton hjalmarssonii, the Fire-shrub, and a Phyllanthus, probably
P. epiphyllanthus, grow in quantities. Where the plains merge into
the loamy flats bordering the salt-ponds and creeks Statice bahamensis
thrives. The type of scrub vegetation as displayed on Grand Turk
has a very peculiar aspect when the Burnt-bush abounds. Its
dark hue, inconspicuous leaves, and black glands give this plant a
sombre appearance, so that one might almost imagine that a fire
had scorched the ground. If it were not for the variety afforded by
the Borrera heath, the Lantana bushes, and the pretty Statice, the
scrub of this island would present a very gloomy aspect in places
where the Burnt-bush predominates.

Although some of these scrub plants, like the Baccharis, the
Phyllanthus, and the Lantana range widely in the West Indian
region, several of them are purely Bahamian; and it is remarkable
that this scrub flora of Grand Turk derives its special impress from
species first described from this island, though but few of them
have proved to be restricted to it. Thus, Euphorbia vaginulata,
Croton hjalmarssonii, Borrera thymifolia, and Statice bahamensis
were first described by Grisebach from specimens obtained by

286

PLANTS, SEEDS, AND CURRENTS

Hjalmarsson in the Turks Islands in 1858. Yet the first has since
been gathered by Nash and Taylor (1904) in the two neighbouring
islands of the Inaguas; the second by Britton, Millspaugh, and
Hitchcock on Great Guana Cay and Fortune Island towards the
middle of the Bahamas; whilst Borrera thymifolia and Statice
hahamensis have probably been since found in the adjacent islands.
It is, however, noteworthy that Dr. Millspaugh has described a new
species of Euphorbia (E. lecheoides) from the sandy scrub-land of
Grand Turk and Great Inagua (Prcenunc. Baham.). It would
therefore seem that the endemism which the Turks Islands appeared
at first to display in the scrub plants of the sandy plains is often
shared with the adjacent islands, the Inaguas and probably also
the Caicos Islands.

Quite a character is given to the scrub vegetation of the plains
in the southern part of Grand Turk by the strand plants that long
ago deserted the beach and permanently established themselves
inland. Here thrive amongst the ordinary scrub such typical
shore shrubs and small trees as Dodoncea viscosa, Sophora tomentosa,
and Coccoloba iivifera, of which only the last appears occasionally
at the border of the beaches. It is not the occurrence of these
plants in the sandy inland plains but the desertion of the shore that
is difficult to understand. However, this matter will be mentioned
again. Here one may notice that the Barbadoes Olive {Bontia
daphnoides), which has probably been introduced, is one of the
shrubs that are frequent in these southern plains.

Another littoral plant frequent on the sandy soil of the interior,
especially on the elevated northern end of the island, is Corchorus
hirsutus. Borrichia arhorescens, also a typical plant of the strand,
often thrives at the foot of the hill-slopes, where they come down
to the creeks and salt-ponds or descend to the beach. A small
shrubby tree, known locally as the Manchineel, is also frequent on
the lower slopes of the ridge bordering North Creek. It has the
habit of the true Manchineel {Hippomane mancinella) and also several
of the seed and fruit characters ; but its fruit is almost pyriform with
pointed apex, and differs in other respects from the depressed globose
fruit of the genuine species. The Manchineel proper, such as often
came under my notice in other parts of the West Indies, did not
present itself to me either on Grand Turk or in any of the other
islands of this small group, though its fruits are one of the commonest
constituents of the stranded drift. Dr. Millspaugh characterises
it as a scrub-land plant widely spread in the Bahamas, including
Grand Turk, where it was collected by Nash and Taylor in 1904
(Prcenunc. Baham., I.). It is noteworthy that the Manchineel fruit
of the Bahamas is described by Catesby as " shaped like a pear or
rather a fig " (Nat. Hist. Carolina, Florida, and the Bahama Islands,
II., 95, 1743). He saw very few of the trees and observed " none
growing on the Sea-Shore." He attributes to them the usual
qualities of the Manchineel proper; but it is evident that as in the
case of the Grand Turk plant we are here dealing with quite another
tree.

2. The Plants of the Rocky Slopes and Ridges in the Interior of Grand

THE FLORA OF THE TURKS ISLANDS 287

Turk. — We are still concerned with scrub, but with scrub of a very
different character from that found on the sandy plains, and with
scrub that is in some localities almost arborescent. Many of the
plants were strange to me. Probably the hilly district near the
North Wells is most typical in these respects, and here the botanist
would find his most interesting specimens. Here plants of the Cactus
kind flourish, particularly Opuntia tuna and another species of the
genus with very long spines, known as " Dildo." In such localities
the Turk's-head Cactus (Melocactus) is at home, though now infre-
quent, together with a smaller Cactus of similar form, perhaps a
kind of Mamillaria. A species of Echites clambers over the rocks,
and the Seven-year Apple (Geniya clusiifolia) grows sporadically
on the stony crests of the ridges. The plant last named is also
found amongst the detached rock-masses at the base of the bluffs
facing the beach on the south-east coast. A fan-palm, perhaps a
species of Thrinax, once grew as I was told in the north part of the
island. Millspaugh in his Prcenuncice Bahamenses names several
Bahamian plants of the Bubiacece collected by Nash and Taylor
in the scrub of this island, such as Catesbcea campanulata, C. foliosa,
Bandia aculeata, Guettarda krugii, etc. ; and he describes a new species
of the EuphorbiacecBy Argythamnia argentea, which had been only
found in the scrub-land of Grand Turk. Harshberger in his general
work (p. 694) refers to a shrubby Pithecolobium, ten to fifteen feet
high, as growing on this island.

Spiny Acacia trees and shrubs, including Acacia farnesiana, A.
acuifera, and one or two other species, grow in places, as on the lower
ground of the North Wells district. Acacia farnesiana may have
been introduced by cattle. A. acuifera was first described by
Bentham from Hjalmarsson's collections in the Turks Islands.
I gathered from Dr. Millspaugh's manuscript that it is peculiar to
the Bahamas, being found also on the islands adjacent to the Turks
Group, namely, the Caicos Islands and the two Inaguas. Here and
there amidst the rocks of the ridges thrives Guilandina bonducella,
which on Grand Turk has practically abandoned its customary
station amongst the vegetation bordering the beach. Thespesia
populnea is another plant that has to a great extent deserted its
littoral station on Grand Turk. One side of the North Wells hollow
is bordered by a copse of these trees situated about a third of a
mile from the beach, where they are still scantily represented.

I have now gone far enough to illustrate the general character
of the flora of the sandy plains and rocky slopes and ridges in the
interior of Grand Turk. We find here plants that the Bahamas
hold in common with other West Indian localities, plants that are
widely spread over the Bahamas but are confined to that archipelago,
plants restricted to the extreme south-eastern islands (the Caicos
and Turks Islands and the Inaguas) and held in common by them,
and plants found only in the Turks Islands, as represented by Grand
Turk. Though the endemism of the Grand Turk plants is probably
not very great, it is sufficient to convince us that we are concerned
here with ancient conditions of isolation.

3. The Strand Plants of Grand Turk. — We are concerned here with

288 PLANTS, SEEDS, AND CURRENTS

plants, most of which the writer was famiUar with in the West Indies
and in other parts of the tropics. The question of endemism is not
here raised, as all of them occur outside the Bahamian area. But
two points require a preliminary notice. In the first place, as already
remarked, a number of the plants have largely deserted the beach,
though they are typical shore species in other regions. In the
second place, the littoral flora often receives accessions from the
scrub of the interior. The shore plants that are rare on the beach
and are found thriving in the scrub of the interior are Coccoloba
uvifera, Dodoncea viscosa, Guilandina bonducella, and Sophora
tomentosa, and to these may be added Thespesia populnea, as it grows
around the North Wells. When they appear at the beach-border
it is only as representatives of the seaward extension of the plants
of the plains and of the hill-slopes. Of the characteristic plants
of the interior that at times establish themselves on the beach,
Euphorbia vaginulata^ the Burnt-bush, is the most conspicuous.
But amongst the other plants of the scrub of the inland plains that
are not infrequently to be observed mingled with the true beach
plants on the sandy tracts that lie in the rear of the beach are Borrera
thymifolia, Lantana involucrata, and Phyllanthus epiphyllanthus.
Whether the typical shore plant penetrates into the plains or whether
the characteristic plant of the inland scrub intrudes on the beach,
it is merely a matter of xerophytes seeking another suitable station.
The influences that tend to keep apart the xerophytes of the plains
and the xerophytes of the beach are concerned rather with the plant's
capacity for dispersal than with differences in station.

The beach that extends for miles along the eastern border of the
island affords excellent opportunities for the study of the arrange-
ment of the strand plants. A sandy, dune-like tract, usually about
fifty yards in breadth, separates it as a rule from the line of bluffs
of seolian sandstone that runs along the length of Grand Turk. At
times, however, the bluffs advance to the beach-margin; and again,
as in the south, they may recede 100 yards or more inland. Al-
though it is often easy to detect a method in the arrangement of
the plants of the beach and of the dune-belt behind, the plants
mingle together as one approaches the bluffs, and at the foot of these
cliffs they grow side by side with the scrub plants of the inland plains.

Walking inshore from the high-water level we first meet with
Ipomoea pes-caprce and Sesuvium portulacastrum, which soon give
place to clumps of Euphorbia buxifolia and Cakile lanceolata. A few
paces back, where the beach proper joins the duny sand tract, we
notice that the foremost mounds are held by the silver-grey shrubs
of Tournefortia gnaphalodes and the bright-green plants of Sccevola
plumieri. Dark clumps of Suriana maritima with its broom-like
habit cover the mounds behind, and the ground we tread upon is
carpeted with Ambrosia crithmifolia. Such is the usual order in
which the plants present themselves as we walk in from the beach;
but they all m.ingle together as we cross the rolling, sandy tract
towards the inland bluffs, at the foot of which they intermingle
with the scrub vegetation of the interior as before described, and
make but scanty efforts to ascend the sandy and rocky slopes.

THE FLORA OF THE TURKS ISLANDS 289

One may notice here an interesting plant which, though not
strictly a shore plant, is most at home when clambering over the
shrubs in the broad, rolling, sandy belt that lies behind the beach
at the south end of the island. This is Passiflora pectinata, which
was first described by Grisebach from Hjalmarsson's collections
on Grand Turk. It is apparently restricted to the Bahamas. Though
at first sight the fruits of Passiflora would not appear suitable for
distribution by currents, it is evident that they can be carried short
distances, and reference is made in Chapter II. to their occurrence
amongst the beach-drift on the south coast of England in different
years. However, the seeds have no buoyancy except when air-
bubbles adhere to them in the dry state, or when the nucleus is decaying
or has decayed. But the fruits would not long endure the " rough-
and-tumble " of an ocean traverse. They owe their floating power
to the buoyancy of the thick rind, which is covered by a tough skin.
It is also possible that birds might aid in the oversea transport
of the seeds, which are sufficiently protected by their crustaceous
shells to be able to withstand a passage in a bird's stomach or in-
testines. In this connection it is noteworthy that Mr. Savage
English remarks in the case of the island of Grand Cayman that
" Passiflora cuprea, L. (a Bahamian, Cuban, and probably also a
Jamaican species), has apparently been brought by a bird within
the last few years, and is certainly being rapidly spread (in the island)
by this means " (Kew Bulletin, 1913, p. 368).

The Mangroves of Grand Turk. — In the development of the salt
industry, which has been established here since the seventeenth
century, there has been a great clearance of the mangroves. Whilst
in the case of Salt Cay the mangroves have been from this cause
nearly banished from the island, there is a considerable remnant in
Grand Turk of the extensive mangrove belt that must have originally
lined all the creeks and lagoons. It is well represented in South
Creek ; but most of the mangroves there appeared of recent growth,
and I was told that up to late times there have been large clearances
made here. But the mangrove belt soon grows again. However,
in 1911 its appearance in South Creek gave one an idea of its original
condition. Near its mouth South Creek is fringed by a dense belt
of Rhizophora mangle backed on the landward side by Laguncularia
racemosa, Avicennia nitida, and occasionally Conocarpus erectus.
However, isolated patches of mangrove here extend into the heart
of the island on the shores of shallow lakelets, which no doubt at
times are in communication with South Creek. In North Creek
at the opposite end of the island mangrove is very scanty. There
are patches of Rhizophora and Avicennia at its mouth, with some
Avicennia trees on the west shore and one or two at the head. Lagun-
cularia is very rare at North Creek. I only saw one tree.

A curious mingling of mangroves with the beach flora and with
plants of inland plains is to be noticed occasionally on Grand Turk,
where the sea-beach and the lagoon borders meet at the foot of a
slope. Here Rhizophora mangle, Laguncularia racemosa, Avicennia
nitida, Suriana maritima, Coccoloba uvifera, Borrichia arborescens,
and Euphorbia vaginulata grow together on the loamy mud-flat,
u

290 PLANTS, SEEDS, AND CURRENTS

Halophytes grow in abundance on the muddy shores of the creeks
and salt-ponds of Grand Turk. The most frequent are Batis mari-
tima, Salicornia ambigua, and a species of Sesuvium, with a species
of Suceda in places, and Borrichia arhorescens at the landward border
of the flats.

The Introduced Plants of Grand Turk. — I need only refer here
to the plants of waste ground which the white man has spread over
the tropics, such as Argemone mexicana, Datura stramonium, Ricinus
communis, and Vinca rosea. One of the first things to attract the
notice of the stranger when he lands at the town is an extensive
bank of Calotropis procera on the sea-front.

Endemism and Isolation in the Turks Islands. — The data at my
disposal only allow of a brief reference to this subject and in a
tentative fashion. The bathymetrical surroundings of the Turks
Islands are discussed in the chapter on the geology of this small
group. It is highly probable that as a unit in the great Bahamian
archipelago the Turks Bank has always maintained its isolated
condition. North and south the submarine slopes descend to depths
of 2000 fathoms and over. The broad trench dividing the Turks
Bank from the Caicos Bank on the west must be about 1500 fathoms
deep opposite the two banks ; but they are connected to the south-
ward by a " col " covered by 1500 feet (250 fathoms) of water. Yet
this is the only evidence of a former possible connection with existing
land-surfaces, since away to the eastward stretch three submerged
banks which, except on the Turks Group side, are surrounded by the
ocean's depths. In these respects the isolation of the Turks Islands
is typical of the eastern Bahamas, where the banks on which the
islands rise may be separated by depths of 1000 to 2000 fathoms.
Endemism ought, therefore, to be well displayed in the Bahamian
archipelago, more especially in the east ; but it would be kept in
check by the monotony of the climatic, geological, and soil con-
ditions. It is exhibited in the plants, the land-molluscs, and the
reptiles, but with a special Bahamian impress. Several of the
plants first described from the Turks Islands have been found in
the neighbouring islands, and it seems likely that the leading feature
of the endemism of this small group is that which it shares with the
Caicos Islands and the two Inaguas. There has been constant
intercourse between them for the last two centuries and more, and
it may be that the aborigines during earlier periods aided in bringing
about the mingling of their respective floras.

The Flora of the Turks Islands from the Standpoint of Dispersal. —
The plants fall conveniently into two groups, those of the shore and
those of the inland scrub. The former are not only found over the
West Indian region, but often also in the Old World. The latter
are all plants of the New World, some occurring also in the other
West Indian islands, others widely spread over the Bahamas and
confined to that archipelago, others confined to, but held in common
by, the Turks and Caicos Islands and the two Inaguas, and a few
restricted to the Turks Group.

The shore plants found in the Old World include —
Avicennia nitida (Currents).

THE FLORA OF THE TURKS ISLANDS 291

Canavalia obtusifolia (Currents).
Cenchrus echinatus (Birds, in plumage).
Conocarpus erectus (Currents).
Cor chorus hirsutus (Drifting logs and man).
Dodoncea viscosa (Currents, man, etc.).
Guilandina bonducella (Currents).

Jleliotr opium curassavicum (Floating logs, pumice, man).

Ipomoea pes-caprce (Currents).

Laguncularia racemosa (Currents).

Portulaca oleracea (Floating logs, pumice, man).

Khizophora mangle (Currents).

Sccevola plumieri (Currents and frugivorous birds).
Sesuvium portulacastrum (Floating logs, pumice, man).
Sophora tomentosa (Currents).
Suriana maritima (Currents and floating logs).
Thespesia populnea (Currents and man).

The shore plants confined to the New World, and as a rule widely-
spread over the West Indies, include —

Ambrosia crithmifolia (Drifting logs and man).

Batis maritima (Currents and man).

Borrichia arborescens (Drifting logs and man).

Cakile lanceolata (Currents for a few hundred miles).

Coccoloba uvifera (Currents and frugivorous birds for distances
not exceeding 200 miles).

Cyperus brunneus (Birds, per pedes et intestina, Millspaugh).

Ernodea littoralis (Frugivorous birds; capacity for dispersal
by currents not tested).

Euphorbia buxifolia (Attached to feet of birds, Millspaugh;
probably also drifting logs and man).

Genipa clusiifolia (Currents to a small extent, iguanas, frugivor-
ous birds, and man).

Ipomoea tuba (Currents. It is regarded by Urban as also an
Old World plant).

Rhachicallis maritima (Means of dispersal unknown, but pro-
bably not by currents).

Salicornia ambigua (Currents, feet of birds, man. By some
regarded as a form of S. fruticosa, an Old World species).

Tournefortia gnaphalodes (Currents).

Uniola paniculata (Regarded by Millspaugh as dispersed by
currents; but no experiments have been made, and pro-
longed floating powers seem unlikely).

(Most of these plants are specially discussed in other pages of this
work. Some of the small seeded species are dealt with in Note 21
of the Appendix, and others like Batis maritima in my work on
Plant Dispersal.)

The association of considerable powers of dispersal by currents
with existence in the Old World is especially noteworthy. Three-
fourths of the littoral shore plants that occur not only all over the

292 PLANTS, SEEDS, AND CURRENTS

West Indian region but also in the Old World possess this capacity,
the others being mostly small-seeded plants, where the seeds are
non-buoyant. In the case of the shore plants confined to the New-
World there are only four that could be transported over great
distances by the direct agency of the currents, namely, lyomoea tuba,
Salicornia ambigua, Batis maritima, and Tournefortia gnaphalodes ;
and it is remarkable that in the first two plants their restriction to
the New World is disputed, their fitness for trans-oceanic dispersal
making a silent appeal against the narrower view of their range.
For the other plants we have to invoke a variety of agencies, such
as birds in different ways, floating logs, pumice, and man.

Of the capacity for dispersal by currents possessed by the plants
of the scrub in the interior of the islands I have very few direct data.
The few that were in immature seed gave little promise of such a
capacity ; but from my extended experience of the buoyant behaviour
of seeds it may be inferred that as in other localities the inland plants
have in the mass been brought here by other means. Neither the
grasses nor the sedges would, it is probable, have been aided in this
way, and doubtless they have often been brought by birds. It is
most likely that frugivorous birds would account for the presence
of Lantana involucrata, Melocactus communis, and Pithecolobium ;
whilst the small seeds or seed-like fruits of the other plants are
probably indebted for their presence here to granivorous birds.
The species of Compositce (Baccharis dioica and Pluchea) may possibly
have been aided by the strong winds, their fruits being provided
with a pappus. I have no data relating to the genus Phyllanihus,
of which two species (P. epiphyllanthus, L., and P. niruriy L.) are
known from the islands (Millspaugh's Prcenunc. Baham.).

(Particulars of the works quoted in this chapter will be found in
the fist of references at the beginning of this volume.)

Summary

1. The vegetation of the Turks Islands, apart from the littoral
plants, is generally sparse and of the scrub type, the soil being
usually sandy.

2. Beginning with the smaller cays, they are described as mainly
occupied by West Indian strand plants, the true scrub-land species
presenting themselves in the larger islands. Amongst the islands.
Greater Sand Cay is regarded as of special interest, since it is the
first to catch the floating drift and illustrates a stage in the plant-
stocking intermediate between that indicated in the small cay a
few hundred yards in length and that exemplified in Grand Turk,
which is five to six miles long (p. 278).

3. After referring to the work of American botanists (p. 283), the
plants of Grand Turk are dealt with more in detail. Its flora derives
its Bahamian impress from the plants of the inland scrub, and its
general West Indian impress chieflv from the plants of the strand
(p. 284).

4. Having described the topography of the island (p. 284), the author
deals with the scrub vegetation, first of the inland sandy plains

THE FLORA OF THE TURKS ISLANDS 293

(p. 285) and then of the rocky upland and the rocky lower levels (p.'286).
It is, however, shown that in the southern end of the island quite
a character is given to the vegetation of the sandy plains by the
abundance of a number of shore shrubs that have largely deserted
the beach (p. 286).

5. As far as the data at the writer's disposal enable him to form an
opinion, they indicate in the case of the inland scrub flora that whilst
some species occur in other parts of the West Indies, others are
restricted to the Bahamas as a whole. Some, again, are confined
to the Turks Islands with the neighbouring Caieos and Inagua
groups, and, lastly, a few are peculiar to the Turks Islands (p. 287).

6. With regard to the strand plants of Grand Turk, it is remarked
that the question of endemism is not here raised, since practically
all of them occur outside the Bahamas and not infrequently also in
the Old World, a conclusion which applies to the true littoral flora
of the Turks Group as a whole (p. 288). Whilst not a few of the shore
plants invade the inland plains, some of them having almost deserted
the beach, the plants of the inland scrub may in their turn intrude
on the beach, mingling there with the characteristic strand flora.
Here the xerophytes of the plain and the xerophytes of the strand
experience little difiiculty in exchanging their stations, the influences
that tend to keep them apart being more concerned with fitness
for dispersal by currents than with station (p. 288). The general
arrangement of the plants on the beach-border is then described
(p. 288).

7. After mentioning the occurrence of a peculiar Bahamian species
of Passiflora in the dune district behind the beach (p. 289), the halo-
phytes of the muddy shores of the creeks and lagoons are named
(p. 290).

8. The mangroves, which once formed extensive swamps on
Grand Turk, Cotton Cay, and Salt Cay, and are still fairly represented
on Grand Turk, are described. The clearings connected with the
establishment of the salt-ponds have almost banished them from
the other islands (p. 289).

9. It is argued that the endemism favoured by the great depths
between and around the Bahamian islands would be checked by
the monotonous character of the climate, geological structure, and
soil conditions over the archipelago (p. 290).

10. With regard to the means employed by Nature in stocking
the Turks Islands, it is observed that two-thirds of the littoral plants
that are found in the Old World could have been directly brought
there by the currents. For the shore plants confined to the New
World, we have usually to appeal to the bird, to the drifting log,
and to man. In the case of the inland scrub plants birds are probably
the chief agents of distribution.

CHAPTER XIII

THE CURRENT-CONNECTIONS IN THE SOUTHERN HEMISPHERE

In this chapter are discussed the current-connections between the
three great land-masses of the southern hemisphere, South America,
Africa, and AustraUa. The matter is scarcely germane to the subject
proper of this work; but, in the light of my own consideration of
the problems involved, I will briefly state the results obtained from
the bottle-drift data supplied by Schott's memoir and from other
sources.

The Relationship between the Southern Floras. — It is
well known that there is a very interesting relationship between the
floras of these three widely separated regions, a subject which has
occupied the attention of Hooker, Grisebach, Engler, Drude, Schimper,
Hemsley, and many others. One of the most important of recent
contributions to the literature of the matter, though more concerned
with animals than with plants, is Mr. Hedley's paper on the palaeo-
geographical relations of Antarctica (Proc. Linn. Soc. Lond., June
6, 1912).

A common source in the northern hemisphere would explain the
presence in these land-masses of the south of several of the genera,
such as Fagus, Podocarpus, Araucaria, etc. ; and here we are simply
assuming that the same principle which has been at work in recent
times within the lives of existing species of Sphagnum and Carex
(see Chapter XVI.) operated also in past ages. Birds would explain
the occurrence of the same species of Accena, Cotula, Nertera, Uncinia,
etc., in the extra-tropical portions of these areas ; and currents would
account for the existence of the same littoral plants, such as Sophora
ietraptera. Convolvulus soldanella, and perhaps Sicyos angulatus,
in regions separated by thousands of miles of ocean. It would,
however, be in the tropics that the currents would be most effective
in accounting for the occurrence of the same species of shore plants
on the opposite sides of the oceans.

The Drift round the Globe in High Southern Latitudes. —
Before dealing with the current-connections of the southern hemi-
sphere I will refer to one of the most interesting phenomena concerned
with the currents of the globe, namely, the drifting round the earth
in high southern latitudes of bottles and wreckage. The subject
is one that could be treated in great detail. Here, however, it
will be only dealt with in an illustrative fashion, and the leading
considerations that arise will be presented in a general way, thus
introducing the discussion that follows.

294

CURRENT-CONNECTIONS IN S. HEMISPHERE 295

On the southern and south-eastern coasts of AustraUa, and even on
the north-east shores of the island continent, there are stranded bottles
and wreckage from off Cape Horn and from the vicinity of the islands
of the Southern Ocean lying north of Kerguelen, such as the Crozets,
St. Paul's, and Amsterdam. Roughly speaking, between the parallels
of 40° and 60° S. lat. the never-failing westerly winds establish a
surface current around the globe, known as the West Wind Drift
Current. Of some sixteen bottles referred to in Schott's memoir
which performed long passages of from 3500 to 8500 miles in these
latitudes, all took an easterly course before the winds of the Roaring
Forties. There is not an exception; and the same remark applies
to numerous bottles in Australian waters south of the 40th parallel,
for the particulars of which we are indebted to Russell, whose " cur-
rent papers " in the Journal of the Royal Society of New South
Wales for 1894 and 1896 are utilised by Schott.

The average minimum drift-rate up to the dates of the recovery
of the bottles is eight to nine miles a day. The quickest rate is
concerned with one that covered the distance of about 4500 miles
between a locality to the north of Kerguelen and its place of arrival
in New Zealand at a speed of at least 10-6 miles a day. If in order
to allow for the delay in the recovery we take the average daily rate
at ten miles, then a bottle drifting round the globe, so as to clear
Cape Horn, would accomplish the circuit of about 12,000 miles in
rather over three years. At this speed a bottle starting from off
the Horn would reach South-eastern Australia in about two and a
third years, a passage of about 8500 miles. Two mentioned by Schott
actually accomplished this traverse, the minimum daily rates up
to the dates of recovery in South-east Australia being 8 and 9-2
miles. One, referred to by Page, even extended its drift around
the east coast of Australia to Cape York, performing a passage of
some 10,500 miles in nearly three years at a minimum rate of about
ten miles a day, one of the longest drifts known.

But the important point is that during the easterly drift across
the Southern Ocean there is a continuous slant to the northward.
Drift always decreases its latitude during long passages in the belt
of the " brave west winds " ; and its general course from off Cape
Horn towards Australia would be about E. by N. and from New
Zealand eastward about E. J N. Thus it is that bottles and wreckage
from off the Horn in about lat. 57° S., from the vicinity of the Crozets
and northward of Kerguelen in lat. 44°-46° S., and from the seas
to the south-west of Cape Leeuwin in lat. 42° S., in all cases cross
the 40th parallel before reaching Australia. The same northward
deflection is to be noticed in drifts across the Pacific in high latitudes,
but the amount is less, the displacement being from two to five
degrees of latitude.

Schott (p. 22) emphasises this northerly slant of the drift in the
Southern Ocean. The result is that Fuegian drift reaches the south
coasts of Australia and the north extremity of New Zealand, which
lie fifteen to twenty degrees further north. Of four bottles cast
overboard off Cape Horn, three of which are referred to by Schott
and one by Page, one reached South-west Australia in the vicinity

296 PLANTS, SEEDS, AND CURRENTS

of Albany, two reached South-east Australia to the eastward of
Melbourne, and one, already mentioned, rounded the south-east
corner of the island continent and reached Cape York, the most
northerly point of Queensland. The figurehead of the Blue Jacket^
a ship that was burned between the Falkland Islands and Cape
Horn in lat. 53° S. and 60° W. in March 1869, was recovered at the
beginning of 1872 at Fremantle in West Australia. This is the only
drift record " at my disposal that illustrates the branching north
from the West Wind Drift Current, as it approaches Cape Leeuwin,
of the West Australian Current. It is quoted by Schott (p. 23)
from the Melbourne Argus for March 28, 1872.

FuEGiAN Drift. — If it were possible for Fuegian drift to be
carried round the earth and back to the western side of South America,
it would strike the coast about twenty degrees north of its original
starting-place. A bottle commencing its voyage round the globe
from Cape Horn would under these conditions be ultimately stranded
on the shores of the same continent somewhere between Valdivia
and Valparaiso. If practicable, this passage of about 15,000 miles at
an average speed of ten miles a day would occupy about four years.
However, Russell's numerous observations in Australian waters
demonstrate its impracticability. Fuegian drift after brushing
past the coasts of South-eastern Australia and Tasmania would,
if it escaped stranding on the north end of New Zealand, be carried
to the north-east for a short distance. It would then come within
the influence of currents setting to the westward and northward
that would sweep it back on the coasts of Queensland, of which an
actual instance has before been given as supplied by Mr. Page.
The westerly set of the currents between Fiji and the Kermadec
Islands would effectually block the passage of Fuegian drift across
the Pacific, and it would similarly prevent the passage eastward to
South America of any Australian drift. This point is well illustrated
in one of Schott's bottle-drift charts (Table 6).

It is apparent from the tracks of bottles laid down in Schott's
charts that whilst Fuegia could distribute drift to South Africa, the
Crozets, St. Paul, and Amsterdam Islands, the southern coasts of
Australia, Tasmania, and the northern extreme of New Zealand,
it could do little more, since the rest of the materials would be swept
back to the Queensland coasts. On rare occasions by making an
unusually wide detour some Fuegian drift might be stranded on Nor-
folk Island and New Caledonia before it was turned back by the
Southern Equatorial Current ; but that would be the extent of its
invasion of the Pacific Ocean.

The only drift that could reach Fuegia from the west would be
derived, as will subsequently be shown, from the southern end of
New Zealand, from the Antarctic islands lying south of it, from
Kerguelen and the islands to the south of it, from the distant South
Shetland and South Orkney Islands, and from the coasts of the
Antarctic continent adjacent to the two groups just named. None
of the drift from the vicinity of Cape Horn could ever return to the
South American continent ; and if any floating objects ever performed
the circuit of the globe in these high latitudes it would be south

CURRENT-CONNECTIONS IN S. HEMISPHERE 297

of the 60th parallel. The bearing of these considerations on the
distribution of littoral plants in the Southern Ocean will be sub-
sequently discussed.

The Current-Connections of Australia. — I will now deal
separately with the current-connections of the great land-masses
of the southern hemisphere as far as they throw light on the distri-
bution of littoral plants in those regions; and in the first place I
will take Australia. The island continent is peculiarly situated
in these respects. Whilst from its tropical north-west shores it
would distribute drift across the Indian Ocean to the East African
coasts, on its south-west border and along the whole length of its
southern coasts it would receive drift, occasionally from South Africa,
but more usually from Fuegia and the intervening islands of the
Southern Ocean. From its south-eastern coasts it would supply
materials to the northern end of New Zealand ; whilst on its middle-
east and north-east coasts would be stranded drift from the islands
of the tropical South Pacific and from Equatorial South America.
The only materials it could receive from New Zealand would be
derived from the vicinity of the North Cape. Such drift, as is shown
below, would be thrown up on the coasts of Queensland, where it
might even be associated, as previously implied, with drift brought
from Fuegia by the West Wind Current.

Dealing first with the eastern coasts of Australia, the data in
Schott's memoir indicate that we are more especially concerned with
the shores of Queensland along its length and with the transporting
agency of the South Equatorial Current. Bottles have been re-
covered on the Queensland coasts not only from the region between
and including Fiji, Tonga, and Norfolk Island, but from off the
distant coast of Ecuador on the other side of the Pacific; and it
may be safely assumed that the eastern archipelagos of the South
Pacific, the Marquesan, Paumotuan, and Tahitian groups, which
lie athwart the track of the trans-Pacific traverse, would also supply
drift to the Queensland coasts.

The principal data, on which the remarks just made are based,
may here be given. A bottle cast overboard about 250 miles from
the coast of Ecuador in lat. 3° 52' S. and long. 85° 38' W. was recovered
966 days afterwards near Cooktown in North Queensland, the
traverse of 7620 miles, as estimated by Schott, having been accom-
phshed at a minimum rate of 7-9 miles a day (Schott, pp. 24, 27,
Chart 6, No. 33). The same traverse was in part accomplished in
mid-ocean by three bottles mentioned by Schott (p. 24, Chart 6,
Nos. 6, 7, 40), which were found in the Paumotus after covering
distances of from 1600 to 2100 miles, having been dropped overboard
in the Eastern Pacific between the parallels of 10° and 12° S. These
bottles, being outside the swiftest part of the current, gave a drifting
rate of only five miles a day. An interesting traverse in mid-ocean,
but more to the north and near the axis of greatest velocity of the
South Equatorial Current, is mentioned by Page. Here a bottle,
dropped overboard on January 23, 1897, in lat. 4°N. and 168° W.
was found on the Gilbert Islands forty-two days afterwards, having
drifted 1100 miles at the rate of twenty-six miles a day, the fastest

298 PLANTS, SEEDS, AND CURRENTS

record for its distance known from this part of the Pacific. Had
this bottle pursued an uninterrupted course, it would probably,
after traversing the Solomon and Lousiade Archipelagos, have been
stranded on Cape York Peninsula. The last part of the ocean-
crossing was effected by four bottles which reached the coasts of
South Queensland and those of New South Wales, just across the
border, from the region of the Western Pacific comprised between
the Fijian and Tongan Groups and Norfolk Island (Schott, p. 24,
Chart 6, Nos. 8, 9, 18, 25).

The evidence afforded by the nine bottle-drifts above dealt with
is clear and consistent. All tell the same story and indicate in no
doubtful manner the probability of drift seeds from tropical South
America reaching the tropical and subtropical shores of Eastern
Australia. The extent to which the distribution of littoral plants
in these two widely separated areas responds to the influence of the
South Equatorial Current will be subsequently noticed. But the
east coast of Australia has other possible current-connections which
have been before mentioned. It is evident from the data supplied
by Russell and Schott that the branch of the West Wind Drift
Current which proceeds through Bass Straits on its way towards
the North Cape of New Zealand is deflected to the northward and
westward, sometimes before and sometimes after passing that head-
land; and the bottle-drift tracks indicate that materials washed
off the North Cape would be stranded in the vicinity of Brisbane. It
would thus appear that the coasts of Queensland would be the recipient
of drift from the extreme north of New Zealand. It would also, as
shown by the stranding of the bottle from Cape Horn on the Cape
York Peninsula, receive Fuegian drift.

Coming to the southern sea-borders of Australia, we have already
referred to the fact that bottle-drift and wreckage from Fuegia,
from the Crozets, and from the islands north of Kerguelen may be
thrown up on these shores. But the south coasts of Australia may
also at times receive drift from South Africa. A bottle cast over
about seventy miles south-east of Cape Agulhas was recovered on
the coasts of the Great Australian Bight (Schott, Map 5, No. 31).
The tropical north-west sea-borders of the island continent have
doubtless received many of their littoral plants from the neighbouring
Malayan region through the agency of the currents. They would,
as is shown on a later page, distribute drift through the South
Equatorial Current to the coasts of tropical and extra-tropical
East Africa. It is possible that materials would be also received
from the branch of the West Wind Drift Current proceeding north
from Cape Leeuwin, which is known as the West Australian Current.
But from the standpoint of distribution any seed-drift from high
latitudes on the Southern Ocean would be ineffective in those warm
regions. It is, however, likely that seed-drift from this source
would be effective on the coasts of extra-tropical Western Australia,
and we have already seen, in the case of the stranding near Fre-
mantle of the figurehead of a ship burned at sea between Cape
Horn and the Falkland Islands, that drift may reach those shores
from the southern extreme of South America.

CURRENT-CONNECTIONS IN S. HEMISPHERE 299

New Zealand as a Receiver and Distributor of Drift. —
This subject has already been several times mentioned in this chapter.
Whilst its north-west shores would receive drift from Southern
Australia and Tasmania, they would also receive the tailings of
drift from Fuegia and the islands of the Southern Ocean (north
of Kerguelen) that had slipped past the Australian and Tasmanian
coasts. On its south-west shores would be stranded materials
from Kerguelen and the islands south of it, and perhaps also some
occasional drift from the islands (South Shetlands and South Orkneys)
and the adjacent coasts of the Antarctic continent south of the
Horn.

Russell, as quoted by Schott (p. 23), gives a number of examples
to show that bottles thrown over south of the 40th parallel between
Tasmania and New Zealand arrive in almost every case at the western
shores of New Zealand. Some longer drifts, as supplied by
Schott in his charts (5 and 6) and as mentioned in his text, are worth
remarking. Thus, a bottle (No. 17) thrown over to the S.S.W. of
Cape Leeuwin in about lat. 41° 30' was stranded close to the North
Cape. Another (mentioned by Russell) thrown into the sea more
to the south-west in about lat. 46° S. and long. 103° E. was recovered
on the south-east coast of New Zealand, after doubling the South
Cape. A third (No. 21) from a position about 200 miles north-east
of Kerguelen and near the 46th parallel was beached at the entrance
to Cook Straits.

That the southern extremity of New Zealand may receive drift
from higher latitudes is indicated by the record of a cask which is
noted by Schott on p. 23. Derived from the whaler Ely, which
was lost on the Macdonald Islands to the south of Kerguelen in
about lat. 53° S., it was ultimately found on the Chatham Islands,
a period of 510 days having passed since the loss of the ship. As
a distributor of drift to the Pacific coasts of extra-tropical South
America, New Zealand plays an important part, a matter that is
discussed below. The possibility of drift washed off its northern
extremity being carried to Queensland has already been noticed.

South America and its Current-Connections. — The circum-
stance that South America reaches south to the 56th parallel, whilst
New Zealand extends to about the 47th and Africa only to the 35th,
has been a determining feature in plant distribution in this part
of the globe. To this factor in the dispersal of plants by currents
must be added another determining influence due to the northern
slant of the easterly drift in the higher southern latitudes. For
this reason Australian drift could never be carried to corresponding
latitudes on the Pacific side of South America ; and, as we have seen,
its traverse of the Pacific Ocean would under any circumstances
be impossible on account of the working of the currents to the north
of New Zealand as interpreted by the bottle-drift data.

On the other hand, materials from the southern end of New Zealand
and from the Antarctic islands to the south of it would be stranded
on the shores of South Chile between Valdivia and the island' of
Chiloe, 40°-43°S. The course that such drift would take is ex-
emplified by the track of a bottle, which, after being cast overboard

300 PLANTS, SEEDS, AND CURRENTS

in the middle of the South Pacific in about lat 46° S. and long. 135° W.,
was picked up on Chiloe (Schott, p. 22, Map 6, No. 38). Materials
from the islands south of New Zealand, such as Auckland and Mac-
quarie Islands, from Kerguelen and the islands south of it, and
from perhaps the distant South Orkney and South Shetland Islands
and the neighbouring shores of Antarctica, would be beached further
south on the coasts of Fuegia and on the islands reaching north
from Cape Pillar to the 50th parallel. A very interesting drift-
record was published in the London Times for April 17, 1912. A
bottle thrown over by Captain Wilkes of the Tyser Line nearly a
thousand miles east of Kerguelen (lat. 51° 38' S. and long. 96° 15' E.)
on November 17, 1908, was recovered about three years afterwards
by Maurice Deffarges on the coast of South Chile in lat. 49° 42' S.
and long. 74° 25' W.

Doubtless drift materials brought from high southern latitudes
by the " west wind drift current " to these shores of South America
would sometimes be carried north by the Humboldt or Peruvian
Current and distributed along the Pacific coasts. It is also possible
that such drift might ultimately be carried past the Galapagos
Islands into the stream of the South Equatorial Current and in this
manner be returned to the north-east coasts of Australia. But
since at least six years would be taken up in the double traverse
from New Zealand to South America and back to Australia, it is
for several reasons doubtful whether as far as seeds are concerned
it would be of any effective value.

One must not ignore the possibility of seed-drift being carried
round the Horn from the west to the east side of Tierra del Fuego.
Not all of that part of the great " west wind drift current " which
strikes the west coast of South America south of the 37th parallel
is deflected north in the Peruvian Current. It gives rise south of
the 50th parallel to a small stream that doubling Cape Horn joins
the Antarctic Current, which proceeding northward meets the
Brazilian Current off the estuary of the Plate. Schott lays down
the track in Map 6 of a bottle which, after being dropped overboard
off the west coast of Fuegia in about lat. 54° S. was recovered in
the Falkland Islands (see p. 22 of his text).

The probability of tropical South America supplying tropical
North-east Australia with littoral plants through the agency of
the South Equatorial Current will be subsequently discussed. On
its eastern tropical coasts South America would receive drift from
tropical West Africa through the Main Equatorial Current, as ex-
plained in Chapter III. ; whilst the South Atlantic Connecting Current
would carry materials from its extra-tropical eastern shores to South
Africa. The fact that drift can double the Horn in the Antarctic
Current and be transferred from the west coasts of Fuegia to the
eastern side of the continent is noticed in the same chapter. But
it is as a distributor of drift to Southern Australia, Northern New
Zealand, the islands to the north of Kerguelen, and occasionally
to South Africa that Fuegia plays the most important role.

Africa and its Current-Connections. — The last of these
southern continental land-masses to be here dealt with is Africa.

CURRENT-CONNECTIONS IN S. HEMISPHERE 301

Its opposite shores display the same reciprocity in the exchange
of drift that is exhibited by South America. Whilst on the west
the tropical borders would distribute drift to the New World through
the agencies of the equatorial currents, those on the east would be
the recipients of drift from tropical North-west Australia and from
Malaya. So also the western extra-tropical coasts would receive
drift from high latitudes in South America, and the corresponding
eastern coasts would distribute it to the southern borders of Australia.

The part taken by the equatorial currents of the Atlantic in trans-
porting drift to America is dealt with elsewhere (Chapter III.). We
are here principally concerned with the materials transported from
the Gulf of Guinea to the coast of Brazil by the Main Equatorial
Current, the time occupied in the passage being only three months.
The western shores of South Africa would receive drift from extra-
tropical South America that had been brought within the influence
of the South Atlantic Connecting Current by the Brazilian Stream
from the north and by the Antarctic Current from the Horn. The
course taken would be that followed by a bottle dropped overboard
in the middle of the South Atlantic in about lat. 42° S. and long.
32° W., which was stranded near the Cape of Good Hope (Schott,
Table 4, No. 97). The indications of bottle-drift data are that drift
could not be carried direct from the tropics of the New World to
those of West Africa in the Counter Equatorial Current, except
under exceptional circumstances (Chapter III.).

To the eastern coasts of Africa, from the equator southward,
tropical drift would be brought across the Indian Ocean by the
South Equatorial Current from Malaya and North-west Australia;
and its destination on the African coast would depend on whether
it took the direct course north of Madagascar, or passed south to
get within the influence of the Mozambique and Agulhas Current.
It is also highly probable that the West Australian Current, which
represents the northern offshoot of the West Wind Drift Current
of the Roaring Forties, would after striking the south-west corner
of Australia carry with it not only West Australian drift-materials,
but also South African drift, which, brought by it within the influence
of the South Equatorial Current, would be ultimately returned to
the continent from which it hailed. It is even possible that Fuegian
drift may be carried into the West Australian Current and thence
into the Equatorial Current, finally reaching tropical East Africa
in the company of South African, Australian, and Malayan drift.
During its traverse of the Indian Ocean this equatorial stream would
deposit samples of its gatherings from four continents on Keeling
Atoll, the Chagos Islands, the Seychelles, the Mascarene Islands,
and Madagascar.

Let us look a little more closely into the play of the currents in
the Indian Ocean from the equator southward, as exemplified by the
tale of the drifting bottle. It is suggestively illustrated in Schott's
maps and in his text; and by adding a few other data we shall
obtain a fair representation of the work of the currents in distributing
drift in these seas. However, to quote from the American bottle-
drift charts for the North Atlantic, it should be noted that the in-

302 PLANTS, SEEDS, AND CURRENTS

dividual drifts as laid down upon the chart, do not necessarily represent
the actual surface currents of the ocean, but the resultant effect of
all the forces to which the bottle was exposed during its drift."

The bottle-drifts of the Indian Ocean are grouped by Schott into
(a) those of the region of the monsoon currents, that is, north of
5°-10° S. lat. ; (b) those of the belt of the South-east Trade between
10° and 30° S. ; (c) and those of the region of the Roaring Forties
or " braven Westwinde." It would appear from his chart and his
remarks (pp. 20-22) that the northern part of the Malayan region
is more likely to receive drift from the westward than to distribute
it in that direction. Thus we should expect to find drift on the
beaches of the west side of Sumatra and of the Malay Peninsula
from Southern India and Ceylon and from the shores of the Arabian
Sea. On the other hand, the bottle-drift data also indicate that
drift may at times be carried from the west coast of Sumatra to the
Maldives and even to the shores of Equatorial Africa. This direct
communication between North-west Malaya and the African east
coast under the equator is exemplified by a bottle thrown over in
about lat. 2° N. some 400 miles west of Sumatra, which was recovered
160 days afterwards under the equator on the East African coast,
having crossed the Indian Ocean at a minimum rate of 18-7 miles
a day, the distance covered being about 3000 miles (Schott, p. 21,
quoted from the American Pilot Chart for June 1895).

In the case of Southern Malaya, meaning thereby the islands east
of Java that face Australia, there would be a regular supply of drift
to the East African coasts through the South Equatorial or South-
east Trade Current. This is illustrated in part by the track of a
bottle which was cast over about mid-way between the island of
Sumbawa and North-west Australia in about 15° S. and long. 116° E.
and was recovered in the Chagos Islands (Schott, Table 5, No. 23).
Its track represents the first half of the passage taken by drift in
crossing the Indian Ocean from the seas between the Malayan
Islands and North-west Australia. The course followed by the
bottle lies close to Keeling Atoll, and thus enables us to appeal to
a witness who particularly interested himself in these matters during
his sojourn in this part of the world, viz. Mr. Wood- Jones. As a
spectator of the actual start in these Malayo-Australian waters of
Malayan drift on its passage across the Indian Ocean to Equatorial
Africa he thus writes in his Coral and Atolls (p. 295) : " During a
stay of a fortnight in October 1906, in a ship lying on cable ground
some twenty miles south of Sumbawa, the current flowed constantly
westward at the rate of about one and a half knots ; and the waters
were carrying all sorts of drift wrack in their stream."

But Wood- Jones aids us still further in this matter. By adding
experiment to observation he enables us to complete the traverse
across the Indian Ocean which was performed in part by the bottle
above alluded to. He had especially in his mind the subject of the
transport in the South-east Trade Current of Malayan drift, whether
plant or animal, to Keeling Atoll; and, as already indicated, the
track of the bottle cast over be ween Sumbawa and North-west Australia
is laid down by Schott as passing close to Keeling Atoll on the way

CURRENT-CONNECTIONS IN S. HEMISPHERE 303

to the Chagos Islands. It was from this atoll that Wood-Jones
made numerous experiments with bottles, the results of which are
specially important in this connection. Although only two were
recovered, both were found on " exactly the same spot " at a place
called Ras Day at Brava (1° 6' N; 44° 2' E.) in Italian Somaliland.
Both of them, strange to relate, were dispatched on the same day,
November 15, 1905, and in both cases the record was returned by
the same person. Captain Piazza, Resident of Brava. The first
was found on May 27, 1906, an interval of 193 days, which gives a
daily drift of not less than seventeen miles over a distance of about
3300 miles. The second was not recovered until July 11, 1907,
the cause of the great delay being not explained. Wood- Jones
(p. 295) considers that drift would require from forty to sixty days to
reach Keeling Atoll from the Malayan Islands to the eastward.
By piecing the data together we may assume that the whole traverse
from south of Sumbawa to Equatorial Africa would be accomplished
in not more than eight months, the distance being about 4500 miles.

As an agent in carrying drift from tropical Africa to Malaya the
Indian Counter Current, which courses eastward along equatorial
latitudes, seems to be ineffective. It is scarcely illustrated in Schott's
maps, and, as in the Atlantic and Pacific Oceans, we may be permitted
to doubt whether any purely compensating current could, except
on very rare occasions, transport drift across an ocean. In the case
of this particular counter-current floating materials would be driven
out of its influence, southward during the north-east monsoon and
northward in the south-west monsoon.

Summing up the effective current-connections between Africa and
Malaya, as far as they are reflected in bottle-drift, we may infer that
Malaya is the giver and Africa the recipient. But it would seem that
whether it came from Sumatra or from the islands east of Java,
Malayan drift reaching East Africa would be mostly gathered under
the equator. This was the opinion also formed by Wood-Jones
when he reflected on the two facts (a) that crocodiles and large
snakes have been stranded alive amongst the Malayan vegetable
drift that is regularly floated to Keeling Atoll, and (b) that bottles
thrown into the sea by him from this atoll had been stranded at
Brava on the coast of Equatorial Africa. " I would dearly love "
(he writes on p. 294) " to examine the coast-line of Italian Somaliland
in the region of Ras Day (Brava) to see if there was not some waif
that had succeeded in making a new home there, and that could
clearly tell of a Malayan or an Australian origin. I do not doubt
that some such colonist would certainly be found — some typical
Asiatic or Australian intruder on the African fauna and flora."

In the westerly traverse of the Indian Ocean in equatorial latitudes
by Malayan drift much would depend on the season of the year.
The bottles dispatched from Keeling Atoll by Wood-Jones in Novem-
ber were impelled westward during the period of the north-east
monsoon which probably came to their assistance when the South-
east Trade failed. Had they been sent off in May, they would,
when near the Line in mid-ocean, have been diverted north towards
India, and when the south-west monsoon gave place a few months

304 PLANTS, SEEDS, AND CURRENTS

later to the north-east monsoon they would have been carried to
the south-west, and might have been the sport of the currents for
years. This seems to have been the fate of a bottle cast over in
May in lat. 6° S. to the south-east of the Seychelles, which was
recovered two and a quarter years after in the Chagos Islands, 800
miles to the eastward (Schott, p. 21, Map 5, No. 8). So again the
bottle before mentioned which was found on the shores of Equatorial
Africa 160 days after it had been dropped into the sea in 2° N. lat.,
some 400 miles west of Sumatra, began its passage in January, that
is, in the height of the north-east monsoon. Had it started in July
during the height of the south-west monsoon, it would have been
carried back to Northern Sumatra or the Malay Peninsula, as is
well brought out in Schott's map in the case of other bottles.

The general effect of the alternating influence of the surface drift
currents set up in the equatorial waters of the Indian Ocean by the
monsoons would be to restrict the arrival on the coasts of Equatorial
Africa of drift from Malaya and North-west Australia to the half
of the year corresponding to the period of the north-east monsoon.
In the other half of the year, if it did not become the sport of the
currents between Ceylon and Madagascar, it might be stranded
almost anywhere on the shores of the northern half of the Indian
Ocean.

This leads us to consider the current-connections of the east side
of Africa with Western Australia, and in so doing we shall be compelled
to cover old ground. Here the South Equatorial Current, or the
South-east Trade Drift, is the direct transporting agency, and Africa
thus figures as the recipient. The track that seeds from the tropical
coasts of North-west Australia would take is indicated (a) by the
bottle, already alluded to, that after being dropped into the sea
about half-way between Sumbawa and the opposite Australian shores
passed close to Keeling Atoll and was stranded on the Chagos Islands,
(b) by the two bottles before mentioned that were carried from
Keeling Atoll to Brava on the African coast in 1° N. lat. Such
seed-drift would presumably, therefore, reach Equatorial Africa.
It would be derived from the adjacent coasts of North-west Australia
and Malaya and from the shores of the Arafura Sea.

But drift from Western Australia in the vicinity of and to the
south of the North-west Cape would also come within the influence
of the South-east Trade Current. With the same northerly slant
that is exhibited in the track of the drift from the Timor and Arafura
Seas, it would arrive at a point in mid-ocean — about the 15th parallel
of south latitude and the 75th meridian of east longitude — where
it would have to choose between a course lying north of Madagascar
bringing it to the vicinity of Zanzibar, and a course south of Madagascar
bringing it into the Natal Current and resulting in most cases in its
being stranded on the shores of Cape Colony. The probable deter-
mining cause would lie in the indirect influence of the monsoons
some degrees further north, the northern course being taken during
the south-west monsoon and the southern course in the north-east
monsoon.

The sequence of events is clearly shown in No. 5 of Schott's charts.

CURRENT-CONNECTIONS IN S. HEMISPHERE 305

A bottle (No. 37) , which was dropped over in about lat. 16° S. and
long. 98° E., nearly 1000 miles north-west of the North-west Cape
of Australia, was recovered on the south-east side of Madagascar.
Presumably it represents the course taken by drift from the vicinity
of this corner of Australia. After a drift westward of about 1100
miles, it crossed in about lat. 15° S. and near the 80th meridian
of east longitude the starting-place of two bottles (18 and 38 of
Schott's Chart 5, and mentioned on p. 22) only 120 miles east and
west of each other, one of which was stranded on the African coast
immediately north of Zanzibar, whilst the other was thrown up on
the south-east shores of Madagascar. Schott lays down the tracks
of bottles from the southern end of Madagascar and its vicinity,
which, after getting into the Natal Current, were beached on the
south coast of Cape Colony east of Cape Agulhas. We thus perceive
how seed-drift from Western Australia may be distributed on the
East Coast of Africa from Zanzibar to the southern extreme of the
continent.

But as regards Australia, Africa may be a giver as well as a re-
ceiver. Drift from the southern extreme may be carried by the
Agulhas Current into the West Wind Drift Current and thus to the
south coasts of Australia. Of this a suggestive example is afforded
by a bottle, thrown overboard about seventy miles south-east of
Cape Agulhas, which was stranded on the shores of the Great Aus-
tralian Bight (Schott, Map 5, No. 31). However, the Agulhas
Current has a subsidiary branch that doubles the Cape, and as
indicated by the bottle-drift data (see p. 63), may bear drift from
the shores of Natal and from the south-east coasts of Cape Colony
to the African West Coasts. Though the event is probably infrequent,,
seeds could be transferred in this way from the east to the west
side of the continent. It is even possible that drift from Western
Australia, after traversing the Indian Ocean to the south of Mada-
gascar might in this manner reach the South-west Coast of Africa.

It is likely that drift in its passage from South Africa towards
Australia may at times perform the circuit of the Indian Ocean.
South African drift, after crossing the ocean in the West Wind
Current, may be carried north in the West Australian branch of
the current into the South-east Trade belt, and thence across the
ocean to Africa, thus completing the circuit of the Indian Ocean.
Wood- Jones (p. 295) refers to a bottle " launched in Mauritius " that
is said to have reached Keeling Atoll. No other data are given;
but he is quite justified in assuming that it " almost certainly came
to the atoll from the eastward, after completing an enormous circuit
of the Indian Ocean." This bottle would have followed the track,
above indicated, to the south of Madagascar and towards the southern
extreme of Africa, subsequently crossing the Indian Ocean in the
belt of the Roaring Forties, and turning north in the West Australian
Current to meet the South Equatorial Current (South-east Trade
Drift) that flows past Keeling Atoll. It would have accomplished
about 10,000 miles in about three years.

The Influence of the Current-Connections in the Southern
Hemisphere on the Distribution of Littoral and Estuarine

306 PLANTS, SEEDS, AND CURRENTS

Plants. — Seed-drift travels west in tropical latitudes and east in
temperate latitudes, from which it follows that whilst in the temperate
latitudes of the southern hemisphere we look to the west for the
source of the littoral and estuarine plants that are dispersed by
currents, in the tropics we look to the east. On account of the
usual slant of the trans-oceanic traverses of the drifting bottles
there is, however, generally a marked shifting of the latitude either
to the north or to the south. But, apart from this, the general
effect would be that in the tropics we should look for West African
affinities on the eastern shores of South America, for South American
affinities on the coasts of Malaya and Australia, and for Malayan
and Australian affinities in East Africa. So also in temperate
latitudes we should look for South American relations in South
Africa, Australia, and New Zealand; for South African affinities
in Australia ; and for Australian and New Zealand relations in South
America.

Although the general principle, just enunciated, still applies,
some important modifications are necessitated on account of the
usual northward and southward slant of the currents, as evidenced
by bottle-drift. Except within the narrow limits of the equatorial
Atlantic the shifting in the latitude generally amounts to several
degrees. We have seen that Fuegian drift when it reaches Australia
has diminished its latitude by about twenty degrees. On the other
hand, New Zealand drift when crossing the Pacific to South America
is deflected only four or five degrees to the north. Bottles from off
the equatorial coasts of South America would strike the shores of
North-east Australia a dozen degrees farther south. This southerly
slant of drift in the South Equatorial Current is continued right
cross the Pacific, and may be even greater than is just indicated. A
bottle thrown into the sea on the 10th parallel of south latitude in
the meridian of the Galapagos Islands would be stranded on the
east coast of Australia on about the 30th parallel of latitude. The
effect of this slant, as already shown, is the throwing back of East
Australian drift on the shores of that island continent, so that
Australia is in this manner unable to contribute drift to South
America. The only drift that could reach South America from these
longitudes would be from higher latitudes, namely, from the southern
end of New Zealand and the Antarctic islands to the southward.

In the southern tropics of the Indian Ocean drift carried along
in the South-east Trade or South Equatorial Current is inclined
to the north, so that bottles dropped into the sea about the
16th parallel of south latitude between Java and North-west Australia
would be beached on the East African coast under the equator.
It is remarkable, as shown by the tracks of bottles laid down in
Schott's Chart 5, that drift from the southern extreme of Africa,
which is carried by the Agulhas Current into the West Wind Current,
is transported across the Indian Ocean without much change of
latitude, being ultimately thrown up on the south coasts of Australia.

In applying, therefore, to the southern hemisphere the principle
that in the case of littoral and other plants dispersed by currents we
should in temperate latitudes look to the west for their source and

CURRENT-CONNECTIONS IN S. HEMISPHERE 307

in the tropics look to the east, we have often to make a correetion
for change in latitude. The problem, when re-stated, would be as
follows. In the tropics of the Pacific we should expect to find plants
of Equatorial South America in Melanesia and North-east Australia ;
in those of the Indian Ocean plants of Malaya and North-west
Australia on the equatorial coasts of East Africa; and in those
of the Atlantic, West African plants on the shores of Brazil and of
the Guianas. In the temperate latitudes we should look for Fuegian
plants in Cape Colony, Southern Australia, and the northern end of
New Zealand ; for South African plants in Southern Australia ; and
for plants of the south part of New Zealand in South Chile. We should
not look for Australian littoral plants in South America. We will
now deal more in detail with these matters : —

(A) As illustrated in Temperate Latitudes, — When the same littoral
plants occur in the cooler latitudes of two of these southern land-
masses we are guided by the currents in determining which of the
two is the source. Thus, there are two littoral plants, Sophora
tetraptera and Convolvulus soldanella, which occur alike in New
Zealand and South Chile. This singular distribution is one of the
mysteries of the Southern Ocean. Both of them possess buoyant
seeds capable of dispersal over an ocean by the currents. Thus,
according to my experiments on the seeds of Sophora tetraptera,
which I gathered on the Chilian coast, half of them remained afloat
after seven months in sea-water and retained their germinative
capacity. From results for the seeds of Convolvulus soldanella, which
are given in my book on Plant Dispersal (p. 542), it appears that 30
per cent, remained afloat after eighteen months in sea-water and
subsequently germinated when sown out. Both of these plants
are confined to the west side of temperate South America. Since
they occur in latitudes north of 42° S. {Ibid., pp. 476-9) they would
come within the influence of the northward flowing Peruvian Current
and would have no opportunity of doubling Cape Horn. They are
found just in those South Chilian latitudes which, as before remarked,
would receive New Zealand drift; and we can have no hesitation
in regarding them as introduced into South America from New
Zealand by the currents. (Both of these plants are treated in detail
in my book on Plant Dispersal. The experiments on iS". tetraptera
were continued after the publication of the earlier work.)

Yet on the part of Sophora tetraptera there has been an effort to
recross the Pacific in warmer latitudes. Not only does it grow in
the Juan Fernandez Islands, whither the seeds were probably brought
from the southward by the Peruvian Current, but it has been found
on Easter Island (lat. 27° S.) in the open ocean. In this last case
it would seem that the seeds, after being carried north in the Peruvian
Current, came within the influence of the South Equatorial Current.
It is not a plant of the tropics, and Easter Island seems to be the
northerly limit of its effective dispersal by currents.

The data indicate the little likelihood of seeds from the temperate
or extra-tropical western shores of South America being able to
arrive in similar latitudes on the Australian side of the Pacific in an
effective condition. Even if the current-connections permitted the

308 PLANTS, SEEDS, AND CURRENTS

transport, it is doubtful whether either the seeds of Convolvulus
soldanella or those of Sophora tetraptera would be able to withstand
the three-and-a-half years' immersion in sea-water that would be
involved in the passage. Effective dispersal of temperate shore
plants by the currents in the Southern Ocean could only be brought
about by the easterly drift in the latitudes of the Roaring Forties.
Very instructive is the caution given to mariners in the Admiralty
chart of the west coast of South America (No. 786). It warns the
navigator against an easterly current setting directly on the coast
between the latitudes of 37° and 50° S. At the southern limit, as
we have seen, would be stranded drift from the seas around Kerguelen
and from the islands south of New Zealand. Towards the northern
imit would be found drift from the southern part of New Zealand.

(B) As illustrated in Tropical Latitudes. — As I have observed in my
previous work, dispersal by currents in tropical seas is a far more
effective agency than in temperate regions. The westerly set of
the equatorial currents is responsible for much that is held in common
among the rank and luxuriant vegetation of coasts and estuaries
in warm latitudes. The principle of looking to the east has an
important application when we are concerned with the existence
of practically the same littoral and estuarine flora on the opposite
sides of the same ocean, as in the cases of the Atlantic and Indian
Oceans. Thus, in the tropical Atlantic we should speak, not of
American plants in West Africa, but of West African plants in
America. So again in the Indian Ocean it is tropical East Africa that
derives its littoral flora from Malaya and North-west Australia.
It would be incorrect to speak of East African plants in Malaya.
The position adopted by Mr. Wood- Jones as regards the dispersal
by currents of tropical plants in the Indian Ocean has been already
stated. His bottle-drift experiments led him to look for Malayan
and Australian intruders in the African flora, or, in other words,
to look to the east and not to the west in order to explain the influence
of the currents on distribution.

In the case of the Pacific it would be useless, for reasons before
given, to seek for tropical Australian plants on the west coast of
equatorial South America. Whatever similarities exist in the
littoral floras of these two regions would result from the transport
of seeds of South American plants westward across the ocean in the
South Equatorial Current. On account, however, of the great
breadth of the Pacific Ocean and the numerous perils to which the
floating seed would be exposed in an ocean traverse of from 7000
to 8000 miles, the Asiatic littoral plants hold the field in tropical
Australia. If we exclude the cosmopolitan beach and estuarine
plants, such as Ipomoea pes-caprce and Entada scandens, that occur
round the tropical zone, it is only occasionally, as with the American
species of Rhizophora (Rh. mangle) in Fiji, that we can find direct
evidence of the extension westward across the Pacific of the estuarine
and coast plants of the west side of equatorial South America.
Island groups in the track of the currents, that would be adapted
to serve as stepping-stones for the westward extension of the South
American mangrove flora, are few.

CURRENT-CONNECTIONS IN S. HEMISPHERE 309

Tropical littoral plants, both strand and estuarine, divide the
warm latitudes of the globe into two great regions, the New World
region including both sides of America and also West Africa, and
the Old World region excluding West Africa and including Poly-
nesia. Whilst several beach plants range through both regions,
more are restricted to only one. Amongst the mangroves and
their associates, the genera Rhizophora, Avicennia and Carapa
occur in both regions, but represented by different species; whilst
Brugiera and Lumnitzera are confined to that of the Old World
and Laguncularia to that of the New World. The contrast between
the two regions is best shown in the mangrove flora, and nowhere
is this better displayed than on the opposite sides of tropical Africa,
all the plants concerned being known to be dispersed by currents.

Looking at the current- connections between Australia and New
Zealand on the one side and South America on the other, we may
infer that whereas New Zealand in its relation with South America
appears both as a giver and a recipient, Australia would receive
South American plants but could make no return. In New Zealand
there is a singular reciprocal relation, the northern island receiving
littoral plants from Fuegia and the southern island returning shore
plants to South America, some nine or ten degrees north of the
Straits of Magellan. It is remarkable that concerning the general
relations of the faunas and floras of these ocean-parted regions of
the southern hemisphere Mr. Hedley arrives at a very similar con-
clusion in his discussion of " the community of austral life " given in his
paper on the palseographic relations of Antarctica (Proc. Linn. Soc.
Lond., June 1912, p. 88), the chief point of difference being that he
considers the transference to have taken place by way of the Ant-
arctic continent. " Whereas New Zealand " (thus he writes) " in its
relation with South America, via Antarctica, appears both as a giver
and a receiver, Australia, on the contrary, seems to have made no
return to South America, but to have received all and given nothing."
It is not without significance that if the questions of the relations
between the faunas and floras of these ocean-parted regions had
been entirely one of currents, Mr. Hedley could not have employed
different language.

One may conclude this chapter with the remark that as far as
the currents are concerned many of the same principles would
apply, with limitations, to the northern hemisphere. Thus we
have in the north the same rule, with the same implications, that
drift travels east in temperate and west in tropical latitudes. This
is abundantly illustrated for the North Atlantic in Chapters III
and IV, and it would also be true of the North Pacific Ocean.

Summary

1. The matter of the current-connections of the southern hemi-
sphere is dealt with here only in so far as it can throw light on the
dispersal of seeds in the Southern Ocean, and the operations of
the currents are discussed only in so far as they are reflected in the
track of the drifting bottle, itself " the resultant effect of all the

310 PLANTS, SEEDS, AND CURRENTS

forces to which the bottle was exposed during its drift." Even in
this respect the field of inquiry is restricted, since it is chiefly littoral
and estuarine plants that are distributed by currents.

2. The author at first refers to one of the most interesting of these
phenomena, namely, the drifting of bottles and wreckage round
the greater part of the globe before the westerly winds in relatively
high latitudes. However, since the easterly drift across the Southern
Ocean displays a continuous northerly slant, the circuit could not
be accomplished by the same bottle unless it started some distance
to the south of the Horn, that is, beyond the 60th parallel as from
the South Shetland Islands. Fuegian drift would be largely inter-
cepted by Australia, Tasmania, and the northern part of New Zealand ;
whilst the tailings that slipped past the North Cape would be thrown
back on the Queensland coasts through the westerly set of the
currents. Drift from the southern extreme of New Zealand would
be stranded on the shores of South Chile, and only drift from the
southernmost of the Antarctic islands would be likely to clear the
Horn. The uninterrupted circuit of the globe in these high latitudes
would take up rather over three years (pp. 294-6).

3. The current-connections of the great land-masses of the south
are then separately dealt with, and Australia is first discussed.
Whilst from its tropical north-west shores it would distribute drift
across the Indian Ocean to the coasts of tropical East Africa and from
its extra-tropical western shores to Cape Colony, it would receive
along the whole length of its southern coasts drift from Fuegia and
the intervening islands of the Southern Ocean, as well as from South
Africa. From its south-eastern coasts it would supply materials
to the north end of New Zealand ; whilst on its middle-east and north-
east coasts would be stranded drift from the islands of the tropical
South Pacific and from equatorial South America. The only materials
it would receive from New Zealand would be derived from the vicinity
of the North Cape : through the westerly set of the currents between
that headland and Fiji they would be carried to the Queensland
coasts, and the same currents would effectively block the passage
of Australian drift across the Pacific (pp. 297-8).

4. In the case of New Zealand a curious reciprocal relation is
noticed. Whilst its northern end would receive drift from Tasmania,
from the south coasts of Australia, and tailings from Fuegia and the
intervening islands of the Southern Ocean north of Kerguelen, its
southern end would distribute drift to South Chile. Drift from the
vicinity of the North Cape would be carried back to the coasts of
Queensland; whilst its south-west coasts would receive drift from
Kerguelen and the islands south of it, as well as from the distant
South Orkney and South Shetland Islands and from the shores of
the Antarctic continent adjacent to them (p. 299).

5. South America is then dealt with. Whilst, as above explained,
it could receive nothing from Australia, there would be stranded on
its shores south of the 40th parallel drift from the south end of New
Zealand as well as from the islands in the higher latitudes to the
westward as named in the preceding paragraph. Drift from its
equatorial Pacific coasts would reach North-west Australia through

CURRENT-CONNECTIONS IN S. HEMISPHERE 311

the agency of the South Equatorial Current. To its tropical Atlantic
coasts the Main Equatorial Current would bring drift from tropical
West Africa ; whilst in the stream of the South Atlantic Connecting
Current would be carried materials from its extra-tropical shores to
South Africa (pp. 299-300).

6. With regard to Africa it is shown that its opposite coasts
display the same reciprocity in the exchange of drift that is exhibited
by South America. Whilst the tropical borders on the west would
distribute drift to the New World through the agencies of the equa-
torial currents, those on the east would be the recipients of drift
from tropical North-west Australia and from Malaya. So also the
western extra-tropical coasts would receive drift from high latitudes
in South America, and the corresponding eastern coasts would supply
it to the southern borders of Australia. The connections across the
Indian Ocean with Malaya and Australia are then discussed. In
the first case it is shown that Malaya is the giver and Africa the
recipient, the drift being transported in the South-east Trade Current
to equatorial East Africa. The general effect of the alternating
influence of the monsoons would be to restrict the arrival of Malayan
drift to the period of the north-east monsoon. In the other half of
the year it might be stranded almost anywhere on the shores of the-
northern half of the Indian Ocean. As regards Australia, it is shown
that whilst drift from its north-west shores would reach tropical!
East Africa, drift from its extra-tropical western coasts might reach
Cape Colony. But as concerns Australia, Africa may be the giver
as well as the receiver, since South African drift may arrive on the
south coasts of Australia by the way of the Agulhas and West Wind
Drift Currents (pp. 300-305).

7. In applying these principles to the distribution of littoral and
estuarine plants in the southern hemisphere it is observed that
seed-drift travels west in tropical latitudes and east in temperate
latitudes. Whilst in the temperate zone we look to the west for
the source of plants that are dispersed by currents, in the tropics
we look to the east. In the tropics we look for South American
plants in North-east Australia, for Malayan and Australian plants
in East Africa, and for West African plants on the shores of
Brazil and of the Guianas. In the temperate zone we look for
Fuegian plants in South Africa, Southern Australia, and the
northern end of New Zealand; for South African plants in
Southern Australia; and for plants of southern New Zealand in
South Chile. Though there is often a marked change in latitude,
the rule holds good that for the source of the elements common
to littoral and estuarine floras on both sides of an ocean we must,
as far as the agency of the current is concerned, look to the east
in the tropics and to the west in the temperate zone (p. 306).

8. In illustration of these principles in the temperate zone the
instances of Convolvulus solda7iella and Sophora tetraptera are taken.
In the tropics, it is shown that whilst in the Indian and Atlantic
Oceans the littoral and estuarine floras on the opposite sides are
closely similar, the fusion has been retarded in the Pacific on account
of the great width of the ocean and the paucity of suitable stepping-

312 PLANTS, SEEDS, AND CURRENTS

stones in the form of islands that would support a mangrove flora
(pp. 307-309).

9. The inference that New Zealand in its relation with South America
figures both as giver and receiver, whilst Australia merely receives
South American plants and makes no return, though here concerned
only with coastal plants, is the identical conclusion framed by Mr.
Hedley with respect to the general relations between the faunas and
.floras of these ocean-parted lands (p. 309).

LIST OF THE PRINCIPAL WORKS QUOTED

GUPPY, H. B., Observations of a Naturalist in the Pacific, Vol. II., Plant-Dispersal,
1906.

Hedley, C, The Palseographical Relations of Antarctica, Proc. Linn. Soc.
London, 1911-12.

Paqb, J., on the bottle-drift observations of the U.S.A. Hydrographic Office,
National Geographic Magazine, Vol. XH., 1901, New York.

Russell, H. C, Current papers in Journ. Roy. Soc. N.S.W., 1894 and 1896. (Quoted
in these pages from Schott's memoir.)

ScHOTT, G., Die Flaschenposten der Deutschen Seewarte, Archiv der Deutschtn
Seewarte, XX., 1897.

Wood-Jones, F., Coral and Atolls, 1910, p. 294.

CHAPTER XIV

DIFFERENTIATION

The author approached the study of plant-distribution through
his investigations into the agencies of dispersal, the results of which
are given in his book on Plant Dispersal. At first inclined to attach
undue importance to these agencies, the effect of his special inquiries
concerning littoral plants and insular floras, he came to learn that,
however efficacious they might be in stocking islands with their
plants, they acquired a diminished significance in continental regions.
We are there brought face to face with problems concerned with
past changes in the history of climate, with the relations of land and
sea in the lapsed geological ages, and with those mysterious revolu-
tions in plant-forms that have affected the whole world. It was the
behaviour of the polymorphous or highly variable species in the
Pacific islands, differentiating as it does in every group, that first
drew his attention towards the real meaning of distribution, a matter
discussed in the work above named.

The Differentiation Theory and its Limitations. — The view
that the history of our globe, as far as secondary causes are in opera-
tion, is essentially the history of the differentiation of primitive
world-ranging generalised types in response to the differentiation of
their conditions, is far from being a novel one. It has been indepen-
dently acquired by a number of investigators; and, indeed, many
lines of inquiry affecting the great groups of animals as well as plants
converge towards this conclusion. It does not, however, attempt to
explain the origin of types, nor does it account for evolutionary
progress, processes which are considered to be under the sway of
other influences that are not at present within our field of cognition.
It is concerned only with the response of organisms to the demands
of their environment, and all that seems purposive in the animal and
plant worlds, all that is bound up with the great scheme of progres-
sive evolution, is viewed much as the old naturalists were wont to
regard it.

The Author's Association with the Theory. — In the last
chapter of his Plant Dispersal, which was published in 1906, the
theory is referred to in different connections. Thus the loss of the
viviparous habit, that is assumed to have been characteristic of
primitive plants under uniform climatic conditions, and the conse-
quent development of the rest-period of the seed, are ascribed to
the differentiation of climate and to the resulting seasonal variation.
But attention is especially paid to the concurrent differentiation of

313

314 PLANTS, SEEDS, AND CURRENTS

climate, bird, and plant, the range of the bird being largely controlled
by the climate, and the range of the plant being mainly dependent
on the bird. In all cases there was the conception of a primal
world, where uniformity of conditions prevailed, and of primitive
generalised types that in their differentiation responded through the
ages to the diversification of their conditions. These views were
considerably extended in a paper on " Plant-Distribution from an
Old Standpoint," read before the Victoria Institute of London in
April 1907, when it was contended that the differentiation theory
presents us with a good working hypothesis for the age of the flower-
ing plants. They were further emphasised and enlarged in a paper
on " The Distribution of Plants and Animals " in Petermann's
Mitteilungen for 1910 (Heft II.). The paper was produced in a
German translation by one of his staff through the courtesy of the
editor ; and although printed in a somewhat abbreviated form there
was no impairment of the general line of the argument.

But in all these statements of his views the author failed to recog-
nise that although the differentiation theory explained the diversity
of forms, there was much in distribution that it did not of itself
account for. What was lacking was the proper appreciation of the
part played by the arrangement of the continents in determining
during secular variations of climate plant- distribution. The de-
ficiency he has endeavoured here to supply; and whilst devoting
this chapter to the discussion of the differentiation theory, he will
deal with distribution as an expression of the geographical and
climatic conditions just mentioned in the chapter succeeding it.

Statement of the Theory. — Natural families, as at present
recognised, seem to fall into two groups, the primitive and the
derivative, the first world-ranging and the second restricted in their
area. The primitive family as differentiation proceeds may give
rise to {a) zonal families, as in the case of the two closely related
families, the PrimulacecB of temperate latitudes and the Myrsinacece
of the tropical zone; (h) continental families, where they are
restricted to a continent, as in the cases of the Tropceolacece and
SarraceniacecB to America; and regional families that are confined
to a more circumscribed region, as in the case of the Goodeniaceoe to
Australia and its vicinity.

That differentiation and decrease of range go together is a prin-
ciple that seems to prevail through the whole plant-world. It is
seen in its last stages in the role of the polymorphous or highly
variable species, which, whilst giving birth to varieties and local
races in different parts of its range, still covers most of the area of
the genus or sub-genus, as the case may be. It is seen even in the
behaviour of the variety so produced ; and thus the process goes on
until, as in Hawaii, different valleys and hill-tops may possess their
own peculiar forms. But this is a subject that has been already
discussed by the author in his work on the Pacific. Here he wishes
to emphasise the point that the behaviour of a polymorphous species
represents, though on a far smaller scale, the behaviour of the primi-
tive generalised family types that once ranged the globe. The
successive stages in the differentiation of a world-ranging family

DIFFERENTIATION

315

type are regarded as a response to the stages in the differentiation
of the conditions.

Although there are still primitive families, like the CompositcBy the
Cyperacece, etc., that occupy most of the globe, there are others
where differentiation has proceeded so far that tho original family
type is lost. The lost type is then only represented in the characters
that join together a number of families in a great plant-group, which,
though they hold the world between them, respectively characterise
different regions of it. There are several such alliances, and some
are referred to in this connection in the author's Victoria Institute
paper. Reference has already been made to the closely related
families of the Primulacece and the Myrsinacece that between them
range the globe, the first in the temperate regions and the second in
the tropics. A similar example is offered by the Geranial alliance,
of which the two oldest families, the Germiiacece and the Oxalidacece,
divide the world between them, the first being most characteristic
of the temperate zones and the last of the warmer regions of the
globe. The great Scitamineous alliance illustrates the same prin-
ciple in the warm regions of the world. Though there is no general-
ised type now known, we find it represented in the characters common
to the four closely connected families that range over warm lati-
tudes : the Zingiberacece mainly in the Old World, the Cannacece and
Marantacece mainly in America, and the Musacece fairly well shared
between both hemispheres.

But the recognition of this principle is not always easy, especially
in those cases where, as in the Pandanacece, we have a family restricted
to the tropics of the Old World with no very near relations in the
New World. Though kindred families are not altogether wanting,
it would be justifiable to presume that the families originally asso-
ciated with it disappeared long since in the differentiating process.
Where special influences have been at work rapidly disguising the
characters of the primitive family, as in the case of the alliance of
the insectivorous families, Sarraceniacece, Nepenthacece and Droseracece,
it would seem that a wide gap must separate them from families of
the same parentage that never acquired this habit. It would not
appear that we could establish any direct connection between the
cosmopolitan Droseracece as the mother family and the closely
related American Sarraceniacece and Asiatic Nepenthacece as the
offspring.

In the family, in the tribe, in the genus, in the species, and in the
variety and local race, we see the same principle at work; and to
illustrate it we will draw nearly all our examples from the same
plant-type. We see it in the fact that the Geraniacece which has
given its name to an alliance of families, still holds most of the area
of the primitive world-ranging type. We see it in the behaviour of
the tribes within the family. Here the tribe Geranice, which comes
nearest to the primitive form, has by far the greatest range, covering
as it does nearly the entire area of the family. We see it in the
genera of this tribe, where Geranium^ the most primitive of all, the
genus that lies farthest back in the line of descent, is the genus most
widely distributed, occupying as it does nearly the range of the tribe.

316 PLANTS, SEEDS, AND CURRENTS

We see it again in the species within a genus ; but in a large genus
Hke Geranium, which holds about 270 known species and has been
subdivided by Knuth in his monograph in the Pflanzenreich series
into thirty sections, we are restricted by the plan of that work to an
appeal to the sections. Small genera are best suited to illustrate
the principle, and in my book on the Pacific it is discussed in the case
of Dodoncea, Metrosideros, and several others. However, its opera-
tion within the sections of Geranium is often clearly exhibited. In
such cases the parent species, or the type around which the other
species group themselves, is highly variable, and has the largest
range, covering the whole or the greater part of the area held by the
section.

Lastly, we see this principle at work within the limits of a species,
and it is especially well exhibited in the varieties and local races of
some of the species of Geranium, Thus, there are species which,
whilst possessing a number of local varieties or races, have a parent
form that includes within its range all the homes of the varieties and
races. The behaviour of G. mexicanum, as indicated in Knuth's
monograph, is very typical. It has the range of the section Mexicana,
to which it belongs, all the other species of the section being confined
to limited areas. It has a number of local forms, all of which group
themselves around a variety that has the range of the species.

Antiquity and Change. — There is not infrequently an obsession
in these matters that time goes with change; and we are now and
then apt to look upon some highly differentiated and rare plant-
organism as far more ancient than some simple plant-type that
abounds around us. This is a dangerous view to hold respecting
family types, concerning which it can be contended with much better
reason that the contrast is merely a matter of varying rates of differ-
entiation. The scores of American genera of flowering plants that
have remained unchanged since Cretaceous and early Tertiary times
show clearly enough that antiquity by no means connotes change.
The only valid explanation of the fact that in one continent a family
may be more differentiated than in another, that is to say, that it
is farther from the family type, is to be found in the more rapid
operation of the process.

Whilst we should expect to find a primitive family represented on
all the larger continental tracts, the absence of some of the derivative
families springing from the primitive type is often to be looked for.
The differentiation theory takes the world as it is. If we find an
explanation of the almost exclusive possession by South America of
the Tropceolacece (one of the Geranial alliance) in the relative isola-
tion of that continent, it would surely be inconsistent to postulate, as
Knuth does (p. 38), a connection between South America and South
Africa in order to account for the occurrence of Geraniacece in both
continents. We must begin with the universal distribution of the
primitive parent type of all the families of the alliance, and allow the
extent of the differentiation to be determined by the arrangement
of the land-masses and their internal conditions. The earlier stages
of the process of change would be on similar lines, whilst the later
changes would diverge widely.

DIFFERENTIATION

317

The Australian Flora. — To illustrate the argument reference
may be made to the Australian flora, where we find world-ranging
families with a speeial Australian impress, such as the Leguminosce
and the Proteacecc, associated with families of later development and
of purely Australian origin which represent, as in the Goodeniacece, a
regional modification of a primitive widely distributed family type,
the modification of which has been so extensive that the connections
with the other descendants of the same family type in other parts
of the world have been lost in the differentiation process. After I
had elaborated this argument in some detail for this chapter I found
that the whole matter had been treated on similar lines, but on a far
more extensive scale, by Mr. E. C. Andrews. Working in Australia,
with abundant material at his disposal and with the willing aid of
some of the foremost of Australian botanists, he has endeavoured to
co-ordinate the evolution of the Australian flora with the develop-
ment of the physical conditions, and it is with his papers on this
subject that I will now deal.

Mr. Andrews had for years devoted himself as a geologist to
unravelling the history of Australia as a land-mass, and he found in
the development of the present land-forms and in the conditions in
which they were produced a key to the various stages in the building
up of the island continent. Whilst thus engaged, his attention was
drawn to a remarkable relation existing in New South Wales between
the arrangement of the purely Australian and extra-Australian
plants and the physical, geological and climatic features of the region.
This led him to reflect on the manner in which the Australian flora
as a whole had responded to the different stages in the development
of the continent, and he was induced to look to the Myrtacece and
Leguminosce as orders especially well fitted for the investigation of
this subject.

In December 1913 his paper on " The Development of the Natural
Order Myrtaeeae" was issued in the Proceedings of the Linnean
Society of New South Wales. For him in this paper the predominant
influence in plant-evolution has been neither Time, nor Heredity,
nor Variation, nor Selection, but geographical environment. The
evolution of floras represents the response of plant-life to variations
in climatic and soil conditions during ages of changing geographical
surroundings. Taking the position that cosmopolitan and genial
climates at different geological periods tended to produce cosmopoli-
tan or widely ranging floras, whilst variation in climate in the past
tended to produce differentiated and localised floras, he applies this
view to the differentiation of the Myrtacece from deduced generalised
primitive forms of the Cretaceous age. It is argued that at this
period the family, responding to the relatively uniform conditions of
a mild and moist climate that prevailed over much of the globe, had
a much wider range than it now has, and that it then covered the
tropics as well as a large part of the present temperate regions.

The manner in which the primitive types differentiated in response
to the differentiation of climatic and other conditions since the late
Mesozoic is then indicated. The early types would become more
and more restricted to the regions that preserved their original

318 PLANTS, SEEDS, AND CURRENTS

environment, that is to say, to the present tropical latitudes. With
the marked diversity of conditions characterising the later periods,
local differentiation of the floras took place in such regions as
Australia and South America, which became more or less isolated
from neighbouring tropical areas. The Myrtacece underwent
divergent transformations." The fleshy-fruited forms, which, as
it is presumed, were nearest to the original types, became character-
istic of the warm regions of the globe. Their characters were those
common to the numerous genera to which they have given rise, the
Eugenias, the Myrtles, the Psidiums, etc. The capsular-fruited
forms mark a later adaptation of the fleshy-fruited types to less
genial conditions, to poverty of soil and to aridity of climate. They
are for the most part Australia's response to the influences working
out the differentiation of the Myrtacece, and we see them now in the
genera Bceckia, Melaleuca, Eucalyptus, etc. In the successive differ-
entiation of tribe and genus Australia, he holds, has played a great
part in the history of the Myrtacece,

There has been no attempt here to summarise a paper which
bristles with so many points that it is difficult to handle it. But not
the least important part of it is that in which Mr. Andrews throws
down the challenge with regard to the older determinations of
Eucalyptus in the Cretaceous and Tertiary formations of the northern
hemisphere. After pointing out that the history of Eucalyptus is
conveyed in the two kinds of leaves which characterise the genus,
the earlier opposite leaves telling a story of the warm genial climates
that prevailed during the Cretaceous and Tertiary periods, and the
later alternate leaves with twisted stalks one of subsequent adapta-
tion to the harsher and more arid conditions of Australia, he observes
that "it is exactly the later more or less xerophytic and unstable
form which has always been reported as existing in the Cretaceous
and Tertiary beds of the northern hemisphere, beds strongly sugges-
tive of moist, genial climates." Mr. Deane's paper on the " Tertiary
Flora of Australia " (Proc. Linn. Soc. N.S.W., 1900) is quoted in
this connection, and we are referred to Mr. Cambage's presidential
address before the Royal Society of New South Wales in 1913.

We have to face this objection, which, until it is sufficiently
answered, will weigh heavily against our belief in the fossilised
Eucalyptus leaves of the north. Yet it would not be antecedently-
improbable that Eucalyptus should repeat the story of two hemi-
spheres, whether in the east and the west or in the north and the
south, which is told in varying forms by Liriodendron, Liquidambar,
Persea, Sassafras, Libocedrus, Sequoia, and other plants. When one
reflects, as Wallace and many others insist, that ancient and once
widespread groups may in our time maintain themselves only in a
few widely separated localities, it is not easy for the west and the
north to abandon their ancient claim to Eucalyptus.

In the following year (1914) Mr. Andrews issued a paper written
on the same lines concerning the Leguminosce, a paper read before
Section E of the British Association in August of that year and
before the Royal Society of New South Wales in the following Novem-
ber, and here as in his paper on the Myrtacece he expresses his great

DIFFERENTIATION

319

indebtedness to Mr. R. H. Cambagc. Like the Myrtacece, the
Leguminosce arc regarded as descended from a few uniform primary
types widely diffused through the world in Cretaceous times and
differentiating in later geological ages in response to the differentia-
tion of conditions. We have here in geological time the same asso-
ciated processes of differentiation of conditions and of differentiation
of types. The Upper Cretaceous period, when the primary type
had a wide range over the globe, was characterised by low-lying
lands and by a mild, moist and genial climate extending from
the tropics to the polar regions. Progressive differentiation of
climate in later geological times, when high mountains, large con-
tinents, and great deserts came into existence, found a response in
the dififerentiation of the types, many of them responding in the
present temperate latitudes to the changes in their environment by
the development of large and important groups of xerophytes, the
evolution taking place along divergent lines in different regions.

In discussing the principles of distribution he lays stress on the
probable great age in Australia of the " pantropical " genera and
on the relative youth of the endemic genera. It is shown that in
Australia the plants which respond to the xerophytic conditions
that prevail there, such as the Eucalypti and the phyllodineous
Acacice^ have only in recent geological times assumed their present
leaf -forms. They represent Australia's response in the differentia-
tion of plant-types that were originally widely spread in the tropics ;
and the more recent development of such generic forms in compari-
son with their parent pantropical types illustrates a principle that
has long been recognised as a corollary of the theory of differentia-
tion. If the theory is true, this is its natural consequence ; and the
principle involved, namely, that antiquity does not connote change,
has been already discussed in an earlier page of this chapter.

Mr. Andrews returns to the attack on those who would deny to
Australia the right to the sole possession of Eucalyptus. " The
evidence " (he says) " is overwhelming against the probability of any
dicotyledonous genus which is endemic in Australasia having existed
in any other continent in either Cretaceous or Tertiary time." He
maintains, and this is a strong point, that if xerophytic types, like
those of Eucalyptus^ the phyllodineous Acacias, Banksia, etc., had
gained access to the waste areas of the other southern land-masses,
and particularly South Africa, they would have found a congenial
home. His general position as regards Australia may be thus
summed up. He would hold that whilst the endemic vegetation of
Australia has been developed within its limits as the result of its
special conditions, the source of its affinities with South Africa and
South America must as a rule be looked for in the common home
of the type in the tropics. Differentiation of types in response to
differentiation of conditions is evidently, to use my own language,
the bed-rock of the views advocated by Mr. Andrews. To employ
his own words : " Traced backward far enough, geographical environ-
ment appears to be the key to evolution."

The Natural Order and Darwinian Evolution. — It follows
from the foregoing remarks that no plant-groups, in the sense of the

320 PLANTS, SEEDS, AND CURRENTS

great orders, could have been produced on the evolutionary lines
implied in the Darwinian theory. To lay down, as the evolutionist
does, that the order of development begins with the variety, varieties
diverging into species, species into genera, and genera into natural
orders, is to reverse the method followed in nature, since it implies
that the simpler, least mutable, and least adaptive characters that
distinguish the great orders are the last developed. This could
never have been. Nature has ever worked from the simple to the
complex, from the general to the particular. Had she followed the
lines laid down by the Darwinian school of evolutionists, there
would be no systematic botany. All would be confusion. There
would be no distribution in the sense in which the term is generally
understood, and the plant- world would be a world of monstrosities.

In the differentiation of a generalised type by which natural
orders break up into tribes, the tribes into genera, and the genera
into species, our systematists have symbolised the process of pro-
gressive differentiation of conditions which has taken place in the
physical world, and this is the result we should expect in a world
where adaptivity reigns supreme. Though we signify our approval
of these systems by our daily use of them, we employ language and
adopt lines of reasoning that are utterly opposed to all that these
systems of classification stand for. In these respects our practice
and our theory are as far asunder as the poles — our practice good,
our theories indifferent.

There lies beside me a very useful little book, written by a botanist
of authority and intended for the use of students. In keeping with
the teaching of the day, it is there explained how in the evolutionary
process the natural order is built up by the varieties diverging into
species, the species into genera, and the genera into groups of genera
or orders, the species being taken as the unit of origin. Yet if we
put this theory into practice in our plant-systems it would spell
chaos. No typical natural order could be produced by such a
method of evolution. The usual process of change in the plant-
world, as in the physical world, has been from the general to the
particular, and we should be quite as illogical in reversing the process
for the plant as we should for its conditions.

Let the reader take a natural order and endeavour to build it up
from one of its own species on the lines suggested by the evolutionist.
With the goal before him of the generalised type of the systematist,
his theory would desert him at the start. What he would attain,
if he persisted in his plan, would be something very different from
our natural orders, a highly specialised type of organism nearing its
extinction. In these respects our practice belies our theory. Were
it not so, our studies of the plant- world would be profitless indeed.

Yet it is not to be supposed that such a process is not in active
operation in nature. Unfortunately for the systematist it is, and
all the oddities in the plant-world are to be placed to its credit.
But the point emphasised is that this is not the process that has
given its impress to the plant-forms of the globe. We live in a
differentiating rather than in a specialising world; and although
speciahsation is common enough, it is very far from being the prin-

DIFFERENTIATION

321

cipal determining cause of the diversification of plant-forms. Let
us look a little further into this matter. Nature displays in the
island and in the continent the two influences of specialisation and
differentiation at work. We should look rather for specialised
genera in islands and for differentiated genera in continents. In
the first instance we have illustrated the Darwinian view, where a
species becomes so modified that it is given a generic rank; but
there is much evidence to show that this is a road which leads to
extinction, the specialised genus having, as a rule, a limited range
and a limited duration. In the case of the differentiated genus of
a continent we have a broad range and a promise of eternity. It is
of such that the plant- world was mainly formed in the past, is largely
composed in the present, and will be made in the future. Specialised
genera may figure conspicuously in localities; but their corpses
strew the path that nature has chiefly followed in the development
of the plant- world.

The great trouble is that we give the same value to products of
very different origin and of very different standing ; the one transient
and limited in range, the other permanent and wide-ranging ; the one
representing nature's failures and the other her successes in stocking
the world with its plants. Whilst specialisation means extinction,
differentiation means a permanence of floral types that will hold the
world as long as there are conditions for plant-life. Take, for
instance, the monstrosities of the Tree Lobelias of Hawaii, of which
some half a dozen genera have been developed in that group. They
were born there and they will die there, and they have been unable to
extend their range. These specialised genera make no effort to
conquer the globe; yet we place them in a list of campanulaceous
genera side by side with such a world-ranging primitive genus as
Campanula.

It would seem that monographers of orders may create their own
difficulties by not recognising this difference between specialised and
differentiated genera in a family. All their difficulties begin when
they try to bring them into line. The specialised genera should be
set apart and treated independently.

Summary

1. The general nature and limitations of the differentiation theory
are briefly discussed, and the author's connection with it is described.
Stress is laid on his failure to recognise in his previous writings that
although it explains the diversity of plant-forms there is much in
distribution that it will not account for, distribution being also an
expression of the influence of the arrangement of the continents
during secular fluctuations of climate. The two subjects are accord-
ingly individualised and treated separately, under the heads of
Differentiation and Distribution, in this and the following chapter.

2. The differentiation of a world-ranging generalised family type
is regarded as a response to the differentiation of originally uniform
conditions. The existing families are viewed as primitive and widely
distributed and derivative and relatively localised. It is considered

Y

322 PLANTS, SEEDS, AND CURRENTS

that in the derivative famihes the process of differentiation has often
proceeded so far that the original family type is lost, being only now
represented in the characters uniting in one great plant-group a
number of families, which, although they hold the world between
them, respectively characterise different portions of it. In the
family, in the tribe, in the genus, in the species, in the variety, and
in the local race, we see the same principle at work, the process
being illustrated in its last stage in the role of the polymorphous or
highly variable species (pp. 313-14).

3. Whilst we should expect to find a primitive family represented
in all the continents, the absence of some of the derivative families
is often to be looked for. To illustrate the argument we may take
the flora of Australia, where there are world-ranging families, bearing
a special Australian impress, associated with families of later develop-
ment and of Australian origin, which represent an extensive regional
modification of a primitive world-ranging type that has been lost in
the differentiating process (pp. 315-16).

4. In this connection attention is drawn to recent papers by
Mr. E. C. Andrews on the development of the Myrtacece and Legumi-
nosce with special reference to Australia. Adopting the view that
the evolution of floras represents the response of plant-life to its
physical environment during ages of changing geographical sur-
roundings, he applies it to the differentiation of these two families
from wide-ranging primitive forms of the Cretaceous period when
relatively uniform climatic conditions prevailed. He challenges the
correctness of the older determinations of Eucalyptus remains in the
Cretaceous and Tertiary deposits of the northern hemisphere, and
claims the genus as Australian-born (pp. 317-19).

5. With this digression the author goes on to show that if the
differentiation hypothesis is correct no natural order could have
been developed on the lines implied in the Darwinian theory, which,
as interpreted in recent works, begins with the variety and termi-
nates with the order, a process that reverses the usual method of
nature (pp. 319-20).

6. Yet such a process, as is there implied, is common enough in
the plant- world; but it accounts not for natural orders, but for all
the oddities of plant-forms. It is here termed a specialising process
in contrast with that of differentiation ; but it is the differentiating
process that has been the principal determining cause of diversifica-
tion in plants (p. 320).

CHAPTER XV

DISTRIBUTION

The differentiation theory could of itself explain distribution only
where a continuous land-area not affected by unstable climatic
conditions is concerned. As our globe presents itself, three factors
control and direct the operations of the differentiating agencies :
(1) the divergence of the land-masses from the north; (2) the secular
fluctuations of climate; (3) the barriers lying athwart the line of
march of migrating plants.

(1) The Divergence of the Land-masses. — Although the differ-
entiation theory explains the diversity of plant-forms, it does not of
itself account for their present distribution. It might do so if this
were a comparatively orderly world with stable climatic conditions,
and if the plants had differentiated in situ over a continuous land-
surface. But a uniformly constituted plant-world of this descrip-
tion does not exist, since differentiation is intensified as one recedes
from the northern polar area, until in the southern lands of South
America, South Africa, and Australia it displays its most pronounced
effects. That floras become more and more dissimilar with distance
from the pole is the result of the continuity of the land-masses in the
north and their disseverment by broad oceans in the south. In
other words, the continuity of the floras of the north and their dis-
continuity in the south represent the response of the plant-world
to the arrangement of the great land-masses.

(2) The Secular Fluctuations of Climate. — If the first factor
alone prevailed, distribution would not be such a very complex
matter, since we could express it as the effect of the differentiating
process controlled by the divergence from a common centre in the
north of the great land-masses of the Old and the New World. But
in so doing we should be ignoring a very important disturbing factor,
namely, the secular climatic changes. During much of geological
time there have been fluctuating conditions of climate which have
produced a series of advances and retreats to and from the north
polar area of the plants of the warm regions of the globe, regions
that have ever been the great home of plant-life.

At a time when a genial climate prevailed over the northern or
land hemisphere the plants now represented in type in the warm
latitudes occupied the regions beyond the Arctic circle. When this
period gave place to cooler conditions the retreat to the south began ;
and the plants, as the diverging continents pulled them more and
more asunder, became more and more distinct from each other as a

323

324 PLANTS, SEEDS, AND CURRENTS

result of the varying differentiating influences of the hemispheres of
the east and the west. When the warm conditions returned, the
plants advancing northward met again in the common gathering-
ground around the pole, but modified by their different experiences
in southern regions lying oceans apart. There they mingled together,
the eastern and the western floras ; and when with the next climatic
change they began again to retreat to their ancient home in the
warm latitudes of the south, the east had borrowed from the west
and the west from the east. The secular climatic changes have,
therefore, tended in this way to mix together the floras of the
globe.

(3) The Barriers athwart the Course of Migrating Plants.
— But another factor has intervened to disturb the effect of the
influence of the divergence of the land-masses and of the secular
fluctuations of climate on the operation of the differentiating agencies.
The contrast between the plants of the eastern and western hemi-
spheres may be, and has been, intensified in an irregular fashion by
the presence in one and the absence from the other of obstacles in
the line of retreat. During their sojourn in the north a huge Hima-
layan range, or a large Mediterranean sea, or a great Sahara desert,
may have been developed and lie athwart their line of march; or a
lofty Cordillera, running with the meridian almost from pole to pole,
may aid the migration between the north and the south. But
always there will have been the great preponderance of land in the
north, and always those two great diverging land-masses of the east
and the west, ocean-parted in the south and meeting in the north.
Thus the distribution of plants may now be expressed as the effect
of the operation of the differentiating agencies under the control and
direction exercised by the divergence of the land-areas from the
north and by secular fluctuations of climate, the resulting migration
of plants to and from the north being checked or aided in different
degrees by the surface-configuration of the continents.

The Views of Sir W. T. Thiselton-Dyer. — How the author
came to recognise that distribution is something more than the
work of the differentiating and dispersing agencies is stated in a
later page. But it should be at once observed that the controlling
influences, as above described, are those which Thiselton-Dyer has
for years emphasised in his writings on distribution. Hooker's and
Bentham's well-known views on the spread of the Scandinavian
flora over much of the globe acquired increased significance in the
author's mind when employed by Thiselton-Dyer in his essay in
Darwin and Modern Science, as illustrating a general principle applic-
able to plant-distribution in geological time.

Distribution, a Problem of the Northern Hemisphere. — In
the following pages the present author has endeavoured to give in
his own words the views stated by Thiselton-Dyer in this essay. In
the tropics, which have ever been the great home or " the area of
preservation " of plant-life, the continents are separated by broad
oceans. In the extreme north, where a permanent home has been
rendered impossible through climatic conditions, the continents meet.
With the land mostly in the north and the sea mainly in the south.

DISTRIBUTION

325

with huge land-masses radiating southward and wide oceans stretch-
ing northward, distribution becomes chiefly a problem of the north.
We cannot get over this fact by raising problems in the south. They
could only be subsidiary. The increasing differentiation of floras
with distance from the Arctic pole leave us no choice in the matter.
It cannot, therefore, be a subject for surprise that of the great land-
masses of the south each tells its own story, and that the discontinuity
between genera and species, so frequent in the south, diminishes as
we approach the Arctic area.

Any theory of distribution will have to explain the abandonment
of share in the struggle on the part of whole groups of plants and
animals that found a sanctuary long ago in the southern lands of
South America, South Africa, and Australia. It will have to face
the fact that these three extremities of the great land-masses diverging
from their common centre in the north have become for plants and
animals cul-de -Sacs, as Thiselton-Dyer terms them, from which
there is no escape. It will have to explain why South America,
South Africa, and Australia have become the abodes of lost causes,
of causes that have been fought for and lost in the north.

The Zoological Standpoint. — Zoologists have often appealed
to the hypothesis of a north polar centre of dispersal in explanation
of their difficulties. Dr. Scharff, in his recent work on The Distribu-
tion and Origin of Life in America (pp. 23, 427), refers in this connec-
tion to the views of Allen, Dahl, Haacke, Tristram, and Wilser, only
to reject them as untenable. " There have been " (he contends)
" scores of great centres of dispersal in the world, and from them
streamed forth new forms in every available direction. Northern
animals advanced southward and southern forms northward, aided,
no doubt, by the ever-changing conditions of climate and the gradual
evolution of oceans and continents."

Yet, if we allow for the occurrence of subsidiary centres, it can
be scarcely said that these views are radically inconsistent with
those advocated in these pages. Standing by themselves they can
hardly do other than make the investigation of distribution a study
of tangled results which may lead us anywhere. The method of
reconstructing the land-surface from the facts of distribution is the
least promising of all the modes of attacking the problem. The
opposite plan is here followed. The very thoroughness of Dr.
Scharff' s work appears to me to emphasise the hopelessness of ever
solving problems of distribution by taking up the ends of the tangled
skein. We must begin with a few general and simple premises that
are beyond dispute, and work forward. Working backward seems
to be the method least likely to evoke order out of the reigning chaos,
and for one among many reasons that we do not yet know the real
significance of many of the lesser facts of distribution, being often
utterly at variance with one another in our interpretation of them.

The Geological Standpoint. — Let us for the moment forget
much about distribution, and start with the fact that there existed
in Tertiary times in the Arctic regions a subtropical climate and a
subtropical vegetation. Let us add to this the second fact that this
vegetation is not to be found within the Arctic Circle now, but in

326 PLANTS, SEEDS, AND CURRENTS

southern regions separated by broad oceans from each other. Let
us connect with these two facts a third, that this migration south
has been associated with a secular change from warm to cold climatic
conditions. The conclusion to which they inevitably lead is rejected
by Dr. Scharff in the case of animals (p. 428) mainly on account of
the absence of geological evidence. But we have the geological
records on our side for the plants ; and if we hold the belief that the
great change both in climate and in flora which has come over the
north since Tertiary times has been repeated in the earlier ages of
the world's history, we stand on much safer ground than if we were
to assume that we are here face to face with a change unprecedented
in the story of our planet. We are not concerned with the north
polar regions as an evolutionary centre, but as the great mixing
ground through the ages of the plants of the eastern and western
hemispheres.

Discontinuous Distribution. — Let us glance at the facts of
discontinuous distribution. Whether we take a genus (A) which,
although represented in the Tertiary deposits of the common meeting
ground of the continents in the north, is now divided by the oceans
in the south, or a genus (B) that is now hopelessly sundered and
isolated in tropical regions and has, as far as is yet known, left no
trace of its original existence in the north, or a genus (C) that is now
restricted in the main to the continents of the temperate latitudes
of the south, the lesson is the same. For discontinuity forms the
essence of the problem, the error lying in treating extreme cases, like
that of Ravenala, as things apart that require a special explanation.
Such cases raise not side-issues, but the main question, the whole
history of distribution being concerned with the effects of discon-
tinuity increasing with distance from the north polar area.

The simplest cases of discontinuous distribution are those illus-
trated by such genera as QuercuSy Fagus, Acer, Juglans, Tilia, etc.,
all represented in the Tertiary deposits of the extreme north, and
now found on both sides of the great oceans to the south, reaching
in some instances, as in that of Fagus, New Zealand and Fuegia.
Less simple cases are those so frequently illustrated among tropical
genera where the geological record, as at present known to us, is
silent as to their original occurrence in the north. But it is legitimate
to assume that the same principle has been at work here, and to
infer with Thiselton-Dyer in his Philadelphia address that during
the warm periods of the Miocene and earlier ages purely tropical
types would have extended north to latitudes where the interchange
between the Old and the New World would not be impracticable.
The behaviour of Ravenala, which is represented by only two known
species, one in Madagascar and the other in tropical South America,
is repeated, though in a less striking degree, by numbers of tropical
genera. We have, for example, J'hespesia (Malvacece), mainly
American and Malayan, and Mammea {Guttiferce), equally shared by
the New World and Madagascar. Then there are Chrysohalanus
(Rosacece) and Critdya (Leguminosce), which are chiefly American,
two genera that are only known in the Old World from Africa and
Malaya. Then there is Desmanthus, a leguminous genus, of which

DISTRIBUTION

327

only one of the ten species occurs outside the New World, namely,
in Madagascar. The number of genera mainly American which have
one or two solitary representatives in the Old World is remarkable.
Several remarkable cases of discontinuity could be cited from the
tropics of the Old World. For instance, Canarina (Campanulacece)
holds three species, found respectively in the Canary Islands, tropical
Africa, and the Moluccas.

Whether in the family, in the tribe, or in the genus, discontinuous
distribution is a familiar feature in the plant-world of the southern
hemisphere. A very ancient history is implied in the representation
of the Proteacece by different genera in Australia, South Africa, and
South America. Students of fossil botany are persistent in claiming
a home for the family in Europe and North America in Cretaceous
and Eocene times; but Thiselton-Dyer, with much to gain from
such a valuable witness on behalf of his views, does not accept the
evidence. As an example of a tribe we may quote his reference to
the MutisiacecB, a tribe of the Compositce, characteristically southern
in its distribution in South America, South Africa, and Australia.
For the genera we may cite Libi^ocedrus and Podocarpus of the
Coniferce. Both of them are indicated amongst the fossil Tertiary
remains of Northern Europe and North America, the first-named even
in Spitzbergen; and both reach extreme southern lands — in the
case of Podocarpus, Southern Chile, South Africa, and New Zealand,
and in that of Librocedrus, New Zealand and Chile.

In the foregoing remarks I have very inadequately illustrated the
important subject of discontinuous distribution. Many of these
genera are now restricted to tropical regions, and the geological record,
as so far interpreted, tells no story of a sojourn in the north. But
many of the genera of trees now confined to temperate latitudes of
North America and Eurasia grew in Miocene times within the Arctic
Circle, and the implication is that in the case of the dissevered
tropical genera they also long ages ago were denizens of the north.
The history of Sequoia, now restricted to California and its vicinity,
but growing in Tertiary times in Arctic latitudes around the pole, is
the story of a genus that has failed. So also there may have been a
similar failure with some of the tropical genera that are now found in
only one of the two hemispheres, either in the Old or in the New World.

The Centrifugal Dispersion from the North during the
LAST Ice Age. — The associated processes of centrifugal dispersion
from the north and of differentiation with distance from the pole are
well described by Prof. Harshberger in his Phytogeographic Survey of
North America (p. 181) ; but he limits its operation to the last of the
great migrations that was connected with the Glacial Period. As
the herd of glacial plants moved south from the far north into each
one of the continental masses, America, Europe and Asia, they were
subjected (thus he writes) to a great variety of conditions, the
outcome being great differentiation of form and the development of new
species.'' This dispersion from the north during the last great Ice
Age has been the theme of Darwin, Asa Gray, Bentham, Hooker,
and many other eminent men of science, a fact to which allusion will
again be made at the close of the chapter.

328 PLANTS, SEEDS, AND CURRENTS

Application of the same Principle to Geological Time. — It
is, however, the feature of the theory advocated by Thiselton-Dyer
that this process of differentiation during the centrifugal dispersion
of plants from the north has affected not merely one migration from
the polar area, but those of all geological periods during which the
land-masses have preserved the main characters of their present
arrangement. Thus he would extend it to the Mesozoic Conifers,
and even suggests it in the case of the Glossopteris flora of Permo-
Carboniferous times. There is this to be said, however, in this last
connection, that we here open up questions relating to the Antarctic
continent, which Seward, in his recent monograph on the fossil
plants collected during the recent expeditions, believes to have been
the centre of the differentiation of the Glossopteris flora (see Brit.
Mus. publications, 1914). But the occurrence of this flora in the
Upper Palgeozoic beds of Russia and Siberia has been established,
and there is something to be said in supjDort of Thiselton-Dyer's
contention in his Philadelphia address that an economy of hypo-
thesis is best served by assuming a northern origin and a dispersal
southward than by calling into existence a vast territory from the
Indian Ocean."

The Views of some Australian Naturalists. — A view, which
is the very opposite of that advocated by Thiselton-Dyer is held by
some Australian naturalists, who consider that " the community of
austral life is explicable only by former radiation along land-routes
from the south polar regions." Hedley, whose important paper on
the palaeographical relations of Antarctica is here quoted (Linn. Soc.
Lond., June 1912), calls as witnesses two genera, Fagus and Aran-
carta, the distribution of which in the past and in the present is
usually regarded as indicating their home in the north. Fagus and
Araucaria, however, cannot be treated together in this connection,
the first named belonging to the age of the Angiosperms, the second
to the Mesozoic Conifers. Though Antarctica apparently does not
share in the history of the plant-world since the appearance of the
Dicotyledons in force in the Upper Cretaceous age, it took a part in
the earlier periods, and whilst prevented from figuring in the history
of the Angiosperms, it may have preserved a record of world-ranging
Conifers.

Let us take the case of Araucaria. In his Philadelphia address
Thiselton-Dyer observes that if we go back to the Jurassic age, and
turn to ConifersE, the structures of which lend themselves to recog-
nition in the fossil state, " we find in Araucaria, a genus now repre-
sented by a few species in both divisions of the southern hemisphere,
abundant evidence that it was once widely dispersed in the northern."
In this connection one may remark that four species of Araucaria
are included in Knowlton's list (quoted by Harshberger, p. 176) of
Cretaceous and Tertiary plants of North America known up to 1898.
In the case of Fagus it will be sufficient to note that eleven species
are referred to it in the list of fossil North American plants just
mentioned. But the linking together of this genus with Araucaria
in support of the Antarctic hypothesis raises another point. One
might admit the presence of a Mesozoic flora of Conifers in the

DISTRIBUTION

829

Antarctic continent without committing oneself to the view that
Antarctica was a Tertiary abode of the flowerinfr plants. Before
quitting this subject it may be added that Mr. Hedley's treatment
of the matter is mainly zoological, and that his arguments can only
be fairly met in their complete form by one who is similarly skilled
as a zoological investigator.

Re-statement of the Views of Sir W. T. Thiselton-Dyer. —
The position adopted by him in his contribution to Darwin and
Modern Science may be again stated before we bring this chapter to
a conclusion. He contends that by postulating the permanency of
the general configuration of the earth's surface, and by assuming
that fluctuating conditions of climate have supplied an effective
means of propulsion from the north, a continuous and progressive
dispersal of species from the land-centre in the north polar regions
is inevitable. One may extend these remarks and say that if it can
be shown, as undoubtedly the general trend of the facts of distribu-
tion does show, that the divergence of plant-types responds to the
divergence of the great land-masses from the north and that dis-
similarity is intensified with distance from that pole, any evidence
for a Tertiary Antarctic centre for the flowering plants would be
discounted in advance. On this view the plant-types most differ-
entiated would be those that had met most rarely in the common
gathering ground of the north ; that is, those of the tropics and of
the southern hemisphere.

It was the recognition by Bentham and Hooker of the continuous
southward migration of the Scandinavian flora over a great part of
the globe that supplied the key for this interpretation of distribu-
tion ; and it was, as Thiselton-Dyer remarks, from the geological
researches of Heer that it received early powerful support as a general
explanation of the geographical distribution of plants. Long ago,
as is again shown, Asa Gray held that the preservation of fragments
of the Cretaceous flora in Asia and America had its explanation in
their having had a common source in the north. As shaped and
promulgated in Darwin and Modern Science this theory removes
more difficulties from the path of the student of distribution than
any previous hypothesis. But it does even more, since in clearing
the road it opens a field of investigation which will take many years
to explore. How distribution may appear when regarded from this
standpoint is exemplified in the comparative study of Carex and
Sphagnum in the next chapter.

Summary

1. The differentiation theory could of itself explain distribution
only where a continuous land- area not affected by unstable climatic
conditions is concerned. As our globe presents itself, three factors
control and direct the operation of the differentiating agencies : the
divergence of the land-masses from the north, the secular fluctua-
tions of climate, and the barriers lying athwart the line of march of
migrating plants. The effect of the first is seen in the increasing
differentiation of floras with distance from the pole, that of the

330

PLANTS, SEEDS, AND CURRENTS

second in the migration of plants to and from the common meeting
ground of the eastern and western floras in the north, and that of
the third in its isolating influence varying in degree on the South
American, South African, South Asian, and Australian floras
(pp. 323-4).

2. The views of Thiselton-Dyer are here adopted. They embody
those of Bentham, Hooker, and Asa Gray in a general principle
applicable to plant-distribution in geological time. From this
standpoint distribution becomes a problem of the northern hemi-
sphere, and we cannot get over this fact by raising problems in the
south (pp. 324-5).

3. After remarking that zoologists have often appealed to the
hypothesis of a north polar centre of dispersal, it is observed that
the method of reconstructing the land-surface from the facts of
distribution is the least promising of all modes of attacking the
problem. The geological record is on the side of the views adopted
in this chapter ; and if we hold that the great change in climate and
in flora which has come over the north since Tertiary times has been
repeated in the earlier ages of the earth's history, we stand on much
safer ground than if we assume that we are here face to face \^'ith a
change unprecedented in the story of our planet (pp. 325-6).

4. It is obserA'ed that discontinuous distribution, which is then
briefly dealt with, is the essence of the problem ; and it is remarked
that the error lies in regarding extreme cases, like that of RaieiiaUiy
as requiring special explanation (pp. 326-7).

5. The important feature of centrifugal dispersion from the north
is again alluded to, in order to emphasise the point that the south-
ward migration generally recognised as resulting from the last glacial
period illustrates a principle that has been in operation through the
ages. The opposing view, which is supported by some Australian
naturalists and has been very ably advocated mainly on zoological
grounds by Hedley, is then discussed. It holds that the community
of austral forms of life is the result of radiation along former land-
routes from the south polar region (pp. 328-9).

6. A restatement of the position adopted by Thiselton-Dyer is
then given, and it is urged that his views remove more difficulties in
the study of distribution than any previous hypothesis (p. 329).

LIST OF SOME OF THE WORKS QUOTED IN THIS AND IN THE
PRECEDING CHAPTER

Akdbews, E. C, The Development of the Natural Order Myrtaceae, Proc. Linn. Soc.
N.S. Wales, December 1913.
The Development and Distribution of the Natural Order Leguminosae, Journ. Proc.
Boy. Soc. y.S. Wales, November 1914.

Cambage, R. H., Presidential Address, Roy. Soc. X.S. Wales, 1913.
Acacia Seedlings, Proc. Boy. Soc. N.S. Wales, July 1915.

Dyeb, W. T. Thiseltox-, Geographical Distribution of Plants, Seward's Darwin and
Modern Science, 1909.
On the supposed Tertiary Antarctic Continent, Journ. Acad. Sat. Sci. Philadelphia,
XV., ser. 2, 1912.

DISTRIBUTION

331

GuppY, H. B., see list at the commencement of this volume.

Hakshberqer, J. W., Phytogeographic Survey of North America: Leipzig and New
York, 1911.

Hedley, C, The Palaeographical Relations of Antarctica, Proc. Linn. Soc.
Lond., 1911-12.

ScHARFF, R. F., Distribution and Origin of Life in America, 1911.
Seward, A. C, Antarctic Fossil Plants, Brit. Antarc. Exped., 1910 : Nat. Hist. Rep.,
Briiish Museum {Nat. Hist.), 1914.

CHAPTER XVI

THE INFLUENCE OF THE DIVERGENCE OF THE CONTINENTS ON THE
DISTRIBUTION OF SPHAGNUM AND CAREX

The predominance of Sphagnum on the middle slopes of Pico and
on the higher parts of San Miguel and Terceira in the Azores first
directed my attention to the distribution of Peat-mosses. Whilst
subsequently studying the matter in Warnstorf's recent monograph
on the Sphagnacece (Das Pfianzenreich, 1911), I became much im-
pressed with the fact that the Sphagnum floras of the eastern and
western hemispheres became more and more unlike as one receded
from the Arctic regions. This led me to realise that I had completely
ignored in my previous inquiries one of the most important factors
in shaping distribution, namely, that concerned with the divergence
of the two great land-masses of the globe from the north polar
area.

From the Peat-mosses I turned to the Carices, another world-
ranging group of plants, and from them received the same reply.
It came as a surprise to me that two groups, so far removed from
each other in the scale of plant-life and differing so greatly in their
capacities for dispersal, should respond in the same way to the
arrangement of the two great land-masses of the Old and the New
Worlds. It was a relief to learn that some months had not been spent
in vain in the comparison of dissimilar things. From the stand-
point of distribution their behaviour proved to be the same, the
differences being only in degree. But perhaps the most welcome
revelation of all was that many of the difficulties associated with the
distribution of the higher plants, such as concern insular floras and
the floras of South America, Africa, and Australia, reappeared,
though in a less intense form, in the distribution of the humble Peat-
mosses. Such uniformity of behaviour, independent as it is of degree
of organisation and of dispersing capacity, deeply impressed me,
and led to my reading over again Dyer's essay in Darwin and Modern
Science on the geographical distribution of plants, the result of which
is shown in the preceding chapter.

Both Sphagnum and Carex respond to the same Law but in
DIFFERENT DEGREES. — From the tabulated results for Sphagnum
and Carex given below, a few general inferences may be drawn. In
the first place, both groups of plants respond to the law involved
in the increase of dissimilarity between the east and the west as
one recedes from the Arctic regions, their differentiation intensifying
with the divergence of the land-masses from the north. Another

332

DISTRIBUTION OF SPHAGNUM AND CAREX 333

Table Illustrating the Effect of the Divergence of the Land-masses
FROM THE North Polar Area on the Distribution op Sphagnum and
Cakkx.

(The limits of the regions employed are as follows : — As Arctic and Subarctic are
included Scandinavia, North Russia, Siberia, Canada, Labrador, and lands north ; as
Temperate, the rest of Europe and Mediterranean Africa, extra-tropical mainland of
Asia excluding Japan, North America between Canada and the subtropical region
next described; as subtropical North American, Georgia, Florida, the Gulf States, and
Mexico; as South American, the mainland only, Central America and the West
Indies being excluded ; as African, aAl except the Mediterranean province; and as
Australian, also New Zealand and Tasmania.)

Regions

Percentage o
occurring
the East a
Hemisphc

Sphagnum

f Species
in both
nd West
res

Carex

Data and Remarks
(The denominator of the fraction
equals the total number of species in
that region. The numerator equals
the number occurring in both hemi-
spheres)

A

East and West
Hemispheres

Arctic

100

80

S. 22: C. 42

22 53

Subarctic

89

29

S. 46: C. 60
52 211

Temperate lati-
tudes

59

11

S. 51 : C. 54

87 502

South America,
Africa, Australia

2

4

S. 3 : C. 6
180 175

Africa and Australia
= East Hemisphere

B

West
Hemisphere

Arctic and Sub-
arctic

90

52

S. 46 : C. 102
51 195

Temperate lati-
tudes

70

24

S. 52: C. 54
74 221

Subtropical North
America with
Mexico

34

11

S. 12: C. 7

35 62

South American
mainland

3(5)

8(16)

S. 3 : C. 6
110 79

South America is here
compared as before
with Africa ; but if the
Eurasian species are
included, the percen-
tages would be in-
creased as indicated
by the figures in
parentheses.

C
West
Hemisphere

Arctic

93

42
45

Carex only

Subarctic

40

60
150

Temperate lati-
tudes

24

54
221

Subtropical North
America with
Mexico

11

7

62

South American
mainland

8(16)

6

79

Note. — The cases are very few where the species do not occur in corresponding latitudes in the
two hemispheres. Since some of the species occur in more than one zone, the same species may
figure more than once in the results for the northern hemisphere. In the southern hemisphere
Africa and Australia together represent the eastern hemisphere. The South American results
refer only to the southern liemisphere. If those held in common with Eurasia were added, the
percentage would be increased as shown above.

334 PLANTS, SEEDS, AND CURRENTS

important principle is probably concerned in the fact that the
more lowly organised Sphagna do not respond to the law to the same
extent as the Carices. It may be that this arises from the greater
capacity for dispersal of the spores of Sphagnum than the fruits of
Car ex ; but all such advantages would, I think, be discounted in the
run of the ages. If we look at the table we notice that the northern
hemisphere is almost large enough for the complete differentiation
of Carex, but it is too small for Sphagnum ; and it would seem that
the lower plants need a larger area for evoking the full effects of
the differentiating process than the higher plants. It might even
happen that the world is not large enough for a particular group of
plants, and that a chaotic confusion of affinities in a geographical
sense would arise which would disappear in a world twice the size.
This involves the principle that lowly organised plants would be
less plastic than higher plants in the same area, or, in other words,
they would respond less to changes of conditions. The point that
our world may not be large enough for the lower plants should not
be forgotten, and some interesting deductions could be drawn
from it.

It will be seen from these pages that free use has been made of
the materials supplied by Warnstorf and Kiikenthal in their mono-
graphs in the Pflanzenreich on the Sphagnacece and the Caricoidece,
Buried deeply in the mass of data contained in this splendid series
of publications there lies the romance of plant-distribution, which
the diligent student can unearth, should he possess the inclination
and the patience. If any success attends my efforts to present as
illustrating real living problems the facts so laboriously collated by
the German investigators, I shall have paid back a little of my debt
to the authors of these monographs.

Explanation of the Table. — Though the table is mainly self-
explanatory, it should be remarked that the materials as arranged
in the monographs do not always lend themselves for precisely the
same treatment, which explains the varying treatment in the columns.
In the first place (A) all the species of North America and Eurasia
are dealt with, excluding those of the subtropical and tropical
zones. In the second and third places (B and C) only those of the
west hemisphere are utilised.

The insular factor comes so much into operation in the northern
tropics, and there are so many disturbing influences affecting a
comparison between the tropical mainlands of the east and the west
in the northern hemisphere, that, except in the mainland of North
America, the warm latitudes have been disregarded. Islands, large
and small, introduce the effects of isolation in a way not presented
by a continent; and the disturbing influences of the insular factor
are again referred to in a later page of this chapter. The necessity
of excluding the island from this table is well exemplified in the case
of Sphagnum. If we were to include Japan in the Eurasian region
and the Malagasy province in Africa, we should find that half of the
endemic Eurasian species (thirty-three in all) did not extend outside
Japan, and that one-third of the African endemic species (forty-
seven in all) are restricted to Madagascar and the Mascarene Islands.

DISTRIBUTION OF SPHAGNUM AND CAREX 335

The general principle that the farther the continents recede from
the north the fewer are the species common to the east and the west
is strengthened by including in the table South America as repre-
sentative of the west hemisphere and Africa and Australia with New
Zealand as representatives of the east. But numerous other con-
siderations arise; and in fact the subsequent discussion is mainly
occupied with the distribution of Sphagnum and Carex in the southern
hemisphere. Here, since the source of these floras is one of the
principal points dealt with, the islands are often permitted to tell
their story.

Comparison of the East and West Hemispheres in the North.
— It is legitimate, in a sense, to compare the endemism of the large
land-masses of the southern hemisphere. South America, Africa,
and Australia, since they are widely separated and independently
situated; but it would be worse than useless to contrast the great
land-masses of the north in their entirety, diverging as they do from
a common centre in the polar area. I will take the case of Sphagnum.
In the combined area of the North American and Eurasian land-
masses there are, excluding the islands, 110 species, of which fifty-
three are found in both hemispheres. A little consideration will
show that the mere statement that 48 per cent, of the North
American and Eurasian species are held in common, however true
it may be, becomes pointless after an analysis of the details of distri-
bution. Thus, of the fifty-three species held in common, forty-six are
Arctic and Subarctic species, and twenty-two are practically circum-
polar. Since, therefore, the species held in common between
Eurasia and North America mostly congregate in the north, we
would expect that the species held separately by these two great
land-masses would gather in the south. This is indeed the case.
Of thirty-nine species confined to North America, only two are found
in Subarctic latitudes. The rest belong to the south, being especially
numerous in the Southern United States. Warnstorf, who had no
theory to support, is emphatic on this point. Whilst, as he says
(p. 38), there is great agreement between the species of the Arctic,
Subarctic, Atlantic, and Pacific regions of North America and
Europe, in the Southern States of the Union and in tropical America
endemism prevails. The rule in North America that the species
it holds in common with Eurasia belong to the north, whilst those
peculiarly its own belong to the south, is also illustrated in Eurasia.
Of the seventeen species restricted to that continent only one is
found in the cold latitudes of the north.

It would be equally futile in the case of the Carices to employ any
common value when contrasting the endemism of Eurasia and North
America. This is sufficiently illustrated in the fact that the number
of species which North America shares with Eurasia gradually
decreases from 93 per cent, in the Arctic latitudes to as little as
11 per cent, in the Southern United States and in Mexico.

The Connections of the South American Sphagnum and Carex
Floras. — The parallelism between Sphagnum and Carex is strikingly
illustrated in the case of the connections of South America with the
rest of the globe. In both genera the predominance of North

336 PLANTS, SEEDS, AND CURRENTS

American species tells a story of the stream from the north; and,
since nearly all of them are also Eurasian, we find a noticeable pro-
portion of Old World forms amongst the species migrating south.
In both there is a connection with Africa of the slightest kind. In
both also there is apparently an Australian and a New Zealand
connection.

The links of South America with the outside world, as exemplified
by the Peat-mosses and the Carices, are here tabulated in a general
way. There are about 110 species of Sphagnum and rather over eighty
species of Carex known from this continent, of which in the first case
eleven species and in the second case twenty-nine species occur
outside it. Since the same species is usually recorded from more
than one region, the totals here given exceed the number of species
concerned.

The Distribution of the non-Endemic South American Species of

SpHAoyvM ^^W) AND Carex

Sphagnum

Carex

North America

18

Eurasia

6

Sphagnum — 6 in Europe, 4 in Asia.
Carex — 10 in Europe, 11 in Asia.

Central America

5

11

Australia and New
Zealand

2

Africa

1

1

The Sphagnum species occurs in
Central Africa. The Carex species
occurs in South Africa.

The facilities offered to migration from the north to the south by the
great mountainous backbone of the western world and the results aris-
ing have often supplied themes to the botanist. An almost unbroken
chain of mountains and highlands, connecting Arctic and Antarctic
lands, is to be found in the American continent, and there alone on
our globe. The only break of importance in this great continuous
mountain chain lies, writes Harshberger (p. 191), in the Isthmus of
Panama, where there is a distance of about 300 miles occupied by
rugged forest-clad hills, between the lofty peaks of Veragua and the
northern extremity of the Andes in New Granada. We should
accordingly expect, as this writer proceeds to say, that this great chain
would form the most effective agent in aiding the southward migra-
tion of the Arctic and north temperate vegetation. In other words,
the plants of the north would have often followed this route south-
ward along the lofty mountains and elevated uplands ; and " we
do find," as the same author continues, " not only that a large number
of northern genera and many species are scattered along this route,
but at the end of the long journey, in Southern Chili and Fuegia,
they are found in numbers sufficient to form an element in the

DISTRIBUTION OF SPHAGNUM AND CAREX 337

flora of those countries." Doubtless birds have played the principal
part in the dissemination of species along this route ; but the high-
lands of the Greater Antilles evidently serve as halting-places in the
track of migratory birds across the Caribbean Sea. In his descrip-
tion of the dispersal of Uncinia by birds, which is quoted in Note 37
of the Appendix, Morris states that migratory birds on their way
north and south between North and South America rest on the high-
lands of Jamaica at elevations of 5000 to 6000 feet above the sea;
and so exhausted are they that they can be caught with the hands
{Nature, December 16, 1886).

The Stream of Plants from the Far North down the Andes
TO Cape Horn. — The stream of species from high northern latitudes
in North America down the Andes to Cape Horn is well illustrated
both by Sphagnum and Car ex. They are all species that are distributed
round the pole in the Arctic and Subarctic regions, both of America
and Eurasia. Half of the species of Sphagnum and a third of the
species of Carex that have been found south of the Straits of Magellan,
that is, in Fuegia, are thence derived. Whilst the main stream from
the north follows the line of the Andes, the outside regions have caught
the eddies ; and, as in the case of Sphagnum in South Brazil, where
only 3 per cent, of the species occur outside South America, the
endemism is intense. Some of the principal conclusions here drawn
with reference to the southward trend of Sphagnum and Carex in
South America are exemplified in the following table ; but naturally
there is much that can be substantiated only by reference to the
original memoirs of Warnstorf and Kiikenthal.

Table illustbatinq the Concentration in the Southern Part of South
America of Arctic and Subarctic Species of Sphagnum and Carex
that are both Eurasian and North American

Total number of
known Species

The North American and Eurasian Species

Number and Per-
centage

Distribution in the North

Sphagnum

Carex

Sphagnum
6=6%

Carex

Sphagnum

Carex

South America

110

81

11 = 14%

Five species
are Arctic
and Sub-
arctic and

one is
Temperate

Eight
species are
Arctic and
Subarctic
and three
are Tem-
perate

Andes only

25

51

4=16%

11=22%

Patagonian
Andes and
Fuegia

8

30

4=50%

11=37%

(A) As illustrated by Sphagnum. — Let us begin with the South
American species of Sphagnum. Out of about 110 species, at present
known, only six have been found outside the New World. They are
S. fimbriatum, plumulosum, mexicanum, pulchricoma, torreyanum,
and medium ; and of these five are Arctic and Subarctic species,
found in all cases both in Eurasia and North America. Four of them
reach the Patagonian Andes, and three extend across the Magellan
z

338 PLANTS, SEEDS, AND CURRENTS

Straits into Fuegia. They may, like S. medium, follow the great
mountainous backbone of the New World from the Arctic Sea to
Cape Horn. This species after extending through the length of North
America, from Alaska southward, reappears in the larger West
Indian islands, and then travels along the Columbian, Bolivian, and
Peruvian Andes at elevations of 10,000 to 11,000 feet, finally reaching
Patagonia and Fuegia. Others, like S. fimbriatum, plumulosum,
and torreyanum, may skip the tropical regions, and after leaving
North America reappear in the Chilian and Patagonian Andes, or
not present themselves again until they arrive in Tierra del Fuego.
Some, like S. mexicanum, though they may not reach farther than
the tropics of South America, exhibit a behaviour very suggestive
of their future discovery far south. At home near the sea-level in
Subarctic latitudes, this species attains an elevation of from 3000 to
3500 feet in the West Indies and Central America, and altitudes of
from 7000 to 10,000 feet in the Equatorial Andes.

(B) As illustrated by Carex. — All that has been said respecting the
streaming of species of Sphagnum down the Andes from high northern
latitudes can be paralleled in the case of Carex, Thirteen of the
eighty-one species described as South American occur outside the
New World. Of these eight are Arctic and Subarctic plants that
are found in all cases in those latitudes, not only in North America,
but also in Eurasia. All of the eight have reached Patagonia and
Southern Chile, and six have crossed the Magellan Straits into
Fuegia; and it will be seen from the table that, as in the case of
Sphagnum, these species from the far north form a considerable
proportion of the Carex flora of Antarctic South America. Some,
vlike C. macloviana, may travel with relatively little interruption from
the shores of the Arctic Sea down the line of the Rocky Mountains
to the Mexican highlands, where this species has been found at an
altitude of 14,000 feet, and then along the Bolivian and Chilian Andes
to Fuegia. Others, like C. goodenoughii, may extend in North
America as far south as Colorado, reappearing in the southern tropics
in Bolivia, before proceeding down the Chilian and Patagonian Andes.
Some, like C. capitata, range southward from the North- West Terri-
tory down the Rocky Mountains, next appearing in Central America,
and following the Argentinian and Patagonian Andes into Fuegia.
But others, like C. microglochin, C. magellanica, and C. canescens,
display great gaps in their passage south from high northern latitudes
to the Fuegian islands, since they skip the tropics altogether and
after following the Rocky Mountains to Colorado next appear in
Patagonia and South Chile. The streaming southward is equally
well illustrated by species confined only to the New World. Thus
C. gayana, after following the whole trend of the Rocky Mountains
from Canada to New Mexico, reappears in the Chilian Andes at
elevations of 8000 to 10,000 feet before it crosses the Magellan Straits
and enters Fuegia. Notwithstanding the gaps, which doubtless will
in some cases be filled up by the future investigator, we have here
suggestively illustrated the streaming of the Carices down the great
backbone of the New World from the shores of the Arctic Sea to
Cape Horn.

DISTRIBUTION OF SPHAGNUM AND CAREX 339

The Connections between South America and the Australian
Region. — This discussion of the route followed by both Sphagnum
and Carex in reaching Antarctic South America from high northern
latitudes raises the question in both cases of the Australian and New
Zealand connections with Fuegia and the Southern Andine region.
In both some of the species have established themselves either in
Australia or in New Zealand ; and the point at issue is the significance
of this fact.

We will first take the case of Sphagnum. Two species that have
reached Fuegia from Arctic and Subarctic latitudes, namely, S. medium
and S. fimbriatum, are also found in South-east Australia and in New
Zealand. There are no other connections between these two regions
as respects Sphagnum, and it might at first appear that one region
had received its species from the other. But a glance at the distribu-
tion of both species makes it clear that just as they have traversed
the whole length of the New World from Alaska to the Straits of
Magellan and beyond, so they have reached Australia from its own
side of the globe, or, in other words, from high latitudes in Asia
by way of the Himalayas, in which last-named area they both
exist.

It can be similarly shown in the case of the Carices that four out
of the six species, which the Australian and New Zealand regions hold
in common with the southern part of South America (South Chile,
Patagonia, and Fuegia), must have been derived from the same side
of the globe by the way of Central and South-eastern Asia. The
occurrence of these four species (C. canescens, oederi, pseudo-cyperuSy
pumila) in Kashmir, Turkestan, South China, etc., renders needless
any appeal to South America as their possible source. It can also
be claimed for South America that the first three of the four species
named were derived overland from the north. Although they have
not been recorded from the tropics of the New World all three are
characteristic of temperate latitudes in North America; and in
postulating for them a southern route by the way of the Mexican
highlands and the Equatorial Andes, we should be merely assuming
that they have done that which has already been shown to have
been accomplished by C. macloviana and other Arctic species. An
objection might be raised in the ease of C. oederi, which is represented
by a variety peculiar to New Zealand, South Africa, and extra-
tropical South America ; but this is met in the subsequent discussion.

The Case of Carex pumila. — Yet, although the evidence is
sufficiently convincing that South America did not receive these three
species of Carex across the Southern Ocean from the Australian and
New Zealand region, in the case of the fourth species, C. pumila^
there is a distinct suggestion that it performed the ocean traverse
from New Zealand to Southern Chile. This Carex has only been
recorded in the New World from Chile; whilst it has an extensive
range in Eastern Asia from Manchuria to Formosa and Hongkong,
whence its extension to Queensland and over the eastern portion
of the Australian continent to Tasmania, and thence to New Zealand,
could be readily assumed. Since, therefore, it would be highly
improbable from the facts of distribution just given that Carex

340 PLANTS, SEEDS, AND CURRENTS

pumila reached the AustraHan and New Zealand region from Chile,
there is good foundation for the view that it is a gift from either
Australia or New Zealand, preferably the latter, to South America.
Accepting that inference, the fact that it has been recorded only
from the western side of the continent, namely, from Chile, clearly
indicates the route taken in its ocean passage, that is, from the
west, which is under the circumstances the only route rendered
practicable by the winds, the birds, and the currents.

The indications supplied by Car ex pumila derive fresh interest
from those offered in the cases of the two other species, C. darwinii
and C. trifida, which, with the four before named, make up the six
species held in common between southern South America and the
Australian and New Zealand region. These two Carices have been
found nowhere else on the globe than in the southern extreme of
the American continent, in New Zealand, and in the islands near
and to the south of it. Presumably there has here been some com-
munication between these two widely separated regions; and the
question that at once presents itself is whether South America
supplied these two species to the New Zealand region, or whether
it received them from that source. In either case it must be assumed
that the sea-bird that transported the seed followed the westerly
winds in its ocean traverse. This being granted, the case of C. darwinii
raises a curious point. Since this species is well distributed over
the Southern Andine region and in Fuegia, and since it occurs only
in the Chatham Islands in the New Zealand and Australian region,
the seed must have been carried eastward from Cape Horn. This
route involves an ocean passage tT\^ce as great as that which would
be implied in the passage westward against the westerty winds from
Cape Horn to the Chatham Islands. But it would be assisted by
the several islands in the Southern Ocean that serve as resting-
places for the sea-birds that are ever flying round the globe in the
latitudes of the Roaring Forties. The evidence of the other species,
Carex trifida, is indeterminate, since it is well distributed in South
Chile and the Falklands Islands in the one region, and in New Zealand
and the neighbouring Antarctic Islands in the other.

The direct Sphagnum and Carex Coxnectioxs between Fuegia
AND THE New Zealand and Australian Region. — From the above
remarks it may be inferred that the parallel already traced between
Sphagnum and Carex may be further extended to the species common
to the southern extreme of South America and the Australian and
New Zealand region. But the parallel is not complete. Whilst
it has been shown that the two species of Sphagnum common to
these widely separated regions must have been derived in each case
from northern latitudes on the same side of the globe, South American
from North America and Australian from Asia, this applies to only
three of the six Carices common to the two regions. In the case of
the others a communication across the Southern Ocean is implied,
in one species from Australia or New Zealand to Chile, in another
from Fuegia to the New Zealand area, whilst in the third there is
nothing to indicate which region was the giver and which was the
recipient.

DISTRIBUTION OF SPHAGNUM AND CAREX 341

The South American and African Connection. — Before leaving
the subject of South America reference may be made to another
point of similarity between Sphagnum and Carex, which concerns
the scanty connection with Africa in the sense below defined. With
both genera the two continents hold but a single species in common,
namely, Sphagnum pulchricoma and Carex cederi. The first named,
which is characteristic of the Southern United States and of tropical
South America, has only been recorded from one locality outside the
New World, namely, in the Lake District of Central Africa. The
second is a typical North American and Eurasian species of Carex
that has extended south as far as Tasmania and New Zealand and
South Africa in one hemisphere, and as far as Patagonia in the other,
being represented in all three regions by the same peculiar variety.
For reasons to be now given it is held that this variety originated
independently in South America and New Zealand, but was supplied
from Patagonia to South Africa. Concerning the parent species
there is no necessity to appeal to any transference across the Southern
Ocean between extra-tropical South America and the Australian
and New Zealand region, since the two regions could have derived
it from northern latitudes on their own sides of the globe, the species
being widely distributed in North America and in Northern and
Central Asia. As regards its occurrence in South Africa, however,
the indications are that this region received the variety across the
ocean from Patagonia, as it is not recorded from any part of the
African continent except from the high mountains of Basutoland, a
matter dealt with in a later page. Reference will also be made
below to the significance of the existence of the New World species
of Sphagnum {S. pulchricoma) in Central Africa.

The African Peat-mosses and Carices. — This brings us to the
discussion of the representation of the Peat-mosses and Carices in
the African continent ; and here again the behaviour of the two genera,
offers a striking parallel, since they illustrate in a similar way that
remarkable isolation which Africa so often exhibits in its flora as
well as in its fauna. By Africa, we mean Africa with the Mediter-
ranean Littoral excluded. This Mediterranean province of the
European region receives from Europe species of Sphagnum and
Carex that as a rule have failed to penetrate farther south. Thus
species of Sphagnum, like S. rufescens and S. turgidulum, which are
widely distributed over Europe, cross the Mediterranean only to
reach Tunis and Algeria. However, although the great majority
of the European Carices have been compelled to halt in North Africa
after crossing the Mediterranean, a few have penetrated to the south
of the continent.

The Check to the Southward Advance of the Carices into
Africa. — Just as in the New World the Carices from the north have
been ever pressing south, so in the Old World the northern Carices
have been ever endeavouring to reach the interior of Africa; but
they have in nearly all cases been rolled back by the obstacles
presented by the Atlas ranges and the sandy wastes of the Sahara
and of Libya. Not more than 13 per cent, of the European species
of Carex that have established themselves in the southern region

342 PLANTS, SEEDS, AND CURRENTS

bordering the Mediterranean have been able to penetrate the con-
tinent and to reach South Africa, the oases of the Desert and the
northern slopes of the Atlas representing as a rule their southernmost
outposts. Thus of about thirty European Carices that have spread
to North Africa only four (C. divisa, vulpina, extensa, acutiformis)
have reached South Africa by travelling along the length of the con-
tinent. There is no prospect with any of the four species that South
Africa received them across the Southern Ocean, either from South
America or from Australia and New Zealand, since they have not
been found there as indigenous plants. All the others, including
species like C. yendula, sylvatica, pseudo-cyperus, vesicaria, halleriana,
and diluta, have either been checked on the Mediterranean border,
or have come to a standstill on the slopes of the Atlas, or have made
their last halt in the Libyan oases.

The Isolation of Africa. — The isolation of Africa, excluding the
Mediterranean province which belongs botanically to Europe, is
well displayed in the behaviour of the genera Sphagnum and Carex,
Though, considering the great area concerned, the representation is
poor, Africa holding about 9 per cent, of the known species of
Sphagnum and only 4 per cent, of the Carices, yet the species are fairly
well distributed. Thus in both cases about half are found in the
tropical portion of the continent, and about a third in the southern
part. The degree of endemism displayed is also very similar, since
both groups of plants are represented by thirty-one species, and of
these six extend outside the continent in the case of Sphagnum and
seven with the Carices.

In the following table Africa is compared with the other two great
land-masses of the southern hemisphere. South America and Australia,
as regards the proportion of its Sphagnum and Carex floras that is
not confined to the continent. As far as South America is concerned,

Comparison in the case of South America, Africa, and Australia, of the
Proportions of non-Endemic Species, that is, of Species extending
outside these Regions

Sphagnum

Carex

Total

Extending out-
side the region

Total

Extending out-
side the region

Islands excluded as
below named

Number

Percentage

Number

Percentage

South
America

110

11

10

81

29

36

Falkland Is., Juan
Fernandez, Gala-
pagos, etc.

Africa

31

6

19

31

7

23

Madagascar, Masca-
rene and Atlantic
Is., etc.

Australia

24

11

46

28

19

68

Tasmania, New Zea-
land, etc.

DISTRIBUTION OF SPHAGNUM AND CAREX 348

these results can only be considered as approximate ; but it is prob-
able that the effect of future discoveries will be to make the endemism
yet more pronounced. The figures, as far as they go, indicate that
the intensity of the endemism is greatest in Africa for the Carices
and in South America for the Peat-mosses. But by taking other-
matters into consideration Africa gives promise of standing first also-
with Sphagnmn. Thus, whilst the species connecting both South
America and Australia with the outer world often range over much
of the globe, most of the African Peat-mosses that extend beyond
the limits of the region, as here defined, do not reach farther than
Madagascar and the Mascarene Islands. Africa owns not one of the
ten or a dozen world-ranging species of Sphagnum, These facts
distinguish the continent in a conspicuous manner from both South
America and Australia.

The Necessity of excluding the Insular Element when

COMPARING THE SpHAGNUM AND CaREX FlORAS OF CONTINENTAL

Regions. — The insular element is removed from this table. The
island by the intensity of its endemism is always a disturbing influ-
ence in discussions regarding the floras of continental regions. The
effect of linking New Zealand with Australia, Madagascar with Africa^
and Japan with Eastern Asia, is to produce results quite out of pro-
portion to the size of the disturbing area. It has already been pointed
out in the case of Sphagnum that if we included Japan in Asia and^
the Malagasy province in Africa half of the known Eurasian species
would be recorded only from Japan, and one-third of the species
peculiar to Africa would be found only in Madagascar and the
Mascarene Islands. So also with the African Carices peculiar to
that region, their number would be increased from twenty-five to
forty if we added those restricted to the Malagasy province. As
shown in the table for the Australian region given on a later page^
the effect of adding the New Zealand Carices to those of Australia
would be to double the number of species. To have employed the*
combined results for Australia, Tasmania, and New Zealand, in
making the above comparison with South America and Africa,
would have caused a drop in the percentage of non-endemic species,
from forty-six to nineteen in the case of Sphagnum and from sixty-
eight to thirty-four in the case of Car ex.

Then it should be remembered that with oceanic archipelagos,
like the Azores, it may make a great difference in the connections
of a whole continental flora if we link them to a continent with which
they have little in common (see Note 22 of the Appendix). The
insular factor, in truth, raises considerations other than those specially
dealt with in this chapter. It may, however, be remarked that both
Sphagna and Carices respond in a similar way to the isolating influ-
ences at play in oceanic islands. We find peculiar species of both
genera associated on islands in all the oceans, as in the Azores and
St. Helena in the Atlantic, in Bourbon in the Indian Ocean, and in
Hawaii in the North Pacific.

We will now look a little closer into the behaviour of the genera
Sphagnum and Carex in Africa, more especially as regards the con-
nections established by the non-endemic species with regions outside

344 PLANTS, SEEDS, AND CURRENTS

the continent, North Africa being regarded as European in a floral
sense. These are indicated in the table below given.

The Distribution of the non-Endemic African Species op Sphaokvm (6)

AND Cahex (7)

Sphagnum

Carex

North Africa

4

Included in the European floral region.

Eurasia

- i 6

For Carex, Europe, 5 ; Asia 6.

North America

1

1

South America

1 i 1

Australia and New
Zealand

2

For Carex, Australia, 1 ; New Zea-
land, 1.

Madagascar and the
Mascarene Islands

5

1

For Sphagnum, Madagascar, 3; and
Mascarene Is., 4.

Amsterdam Island

1

Tenerifie

1

The outside Connections of the African Peat-mosses. — The
Sphagnum connections beyond the continent first claim our attention.
Of thirty-one species recorded from Africa, as geographically here
defined, only six form connections with the outside world, four- fifths
of the species being endemic. Of the six concerned, four merely link
the continent with Madagascar and the Mascarene Islands (Bourbon,
Mauritius, and Rodriguez) ; one of them, S. pappeanum, occurs
on Bourbon and Rodriguez, on Teneriffe, and on Amsterdam, an
island in the centre of the Indian Ocean; whilst the sixth, S. pul-
chricoma, is a characteristic North and South American species that
has only been recorded in Africa from the Tanganyika district.
The limited nature of the external connections of the African
jSphagnum flora is thus apparent ; and it serves to emphasise the view
that Africa stands first among all the great continents as respects the
isolation of its Peat-mosses as well as of its Carices.

It is noteworthy that eighteen of the thirty-one African species
of Sphagnum belong to the subsection Subsecunda, the largest and
most differentiated of all the ten subsections of the genus and holding
one-third of the species. Though it has active centres of differen-
tiation in all the great continents and is more uniformly spread over
the world than the other subsections, these centres are not connected
by world-ranging species. Not one of the ten species of Sphagnum
possessing the widest ranges belongs to the subsection Subsecunda,
and not one of them is African. This isolation of Africa must be
associated with the circumstance that the majority of its species
belong to a subsection that is practically closed to the outside world.
A further implication of this fact will be noticed below. It will be

DISTRIBUTION OF SPHAGNUM AND CAREX 345

sufficient here to restate our present position that in its Umited con-
nections Africa offers a great contrast with South America and
Australia, which are in both cases Hnked by a number of species with
the great land-masses of the north. Africa, it would seem, is a lonely-
continent as far as the Peat-mosses are concerned.

The outside Connections of the African Carices. — Coming
to the African Carices^ we find that although the proportion of those
that extend beyond the limits of the continent, as here defined, is
about the same as in Sphagnum, the genus is brought by the con-
nections of its outside species more in touch with the rest of the
world. The seven species concerned, Carex divisa, vulpina, cernuay
extensa, oederi, acutiformis, boryana, are, with the exception of the last,
wide-ranging Eurasian species that in one or two cases include
Australia and sometimes even North and South America in their
range. The only special connection is that of C. horyanay which
extends merely to Madagascar and the Mascarene Islands.

But in one respect the African Carices repeat in a remarkable way
the behaviour of the Peat-mosses. In view of its isolation one would
have expected Africa to be the home of the older types of these
genera. But the contrary seems to be the case. Just as with
Sphagnum nearly 60 per cent, of the African species belong, as
already shown, to the largest and most vigorous subsection of the
genus, so with Carex more than half of the species belong to the
youngest, most vigorous, and most generally distributed of all the
four subgenera, namely, Eucarex, a subgenus holding two-thirds of
all the known species of Carex, 800 in all. It is remarkable that
Primocarex, the oldest subgenus, almost fails in Africa. It would
thus seem that the invasion of Africa by the Carices and the Peat-
mosses took place during the later stages in the history of the two
genera, and that the occupation of the continent has been followed
by a period of isolation extending to our own times. This similarity
in behaviour on the part of two groups of plants so divergent in
character is a fact of importance.

In the case of Carex the limitation of the species to the continent
often seems to be unaccountably abrupt. Thus, there are four
species (C. echinochlo'e, boryana, longipedunculata, and simensis,
that are evidently distributed over the highlands of tropical Africa
from the Cameroons to Abyssinia and have been found on Ruwenzori
and Kilimanjaro at altitudes of 7000 to 10,000 feet. Though they
extend practically to the eastern and western limits of the continent
only one of them, C. boryana, passes beyond them ; but it does not
travel farther than Madagascar and the Mascarene Islands. In two
of the islands just named. Bourbon and Mauritius, this species meets
C. brunnea, one of the most widely distributed of the Carices in warm
latitudes. Ranging far and wide over Asia, it reaches Australia
across the Malayan region, and finally establishes itself on the Hawaiian
Islands in mid-Pacific. Yet there is no record of C. brunnea from the
African mainland. There must be some important principle in-
volved in the circumstance that Carices find it so difficult to enter
the African continent, and so difficult, when there, to leave it.

Sources of South African Carices and Peat-mosses. — An

346 PLANTS, SEEDS, AND CURRENTS

interesting question presents itself in connection with the sources of
the Peat-mosses and Carices of South Africa, since there are two
alternatives. Their ancestors may have come from the north, over-
land across the continent, or they may have traversed the Southern
Ocean in their passage from either the South American or the
Australian region. Here an appeal must be made to the connections
of species outside the continent.

(A) The Carices. — In the case of Carex the question has been
already raised and answered "v\dth respect to four species, C. divisa,
vulpina, extensa, and acutiformis, which are European species that
having reached North Africa extended their range to the southern
part of the continent, not one of them having been found either
in South America or in the Australian region. Neither of the two
other species concerned, C. cernua and C. cederi, gives a decisive reply.
Thus the first named is a wide-ranging species, which, in the form
of a fairly well-distributed special variety has obtained a slight
hold in Australia in a single locality in New South Wales, a some-
what better footing in New Caledonia, and a secure establishment
in South Africa. Here the indications are indeterminate; but the
scale turns against the trans-oceanic hypothesis, since it seems more
feasible that Asia served as the common focus of dispersal. The
testimony of the second species, C. oederi, is also uncertain. Found in
North America, Europe, and Asia, this Carex is represented by a
special variety, cataractce, in different localities in South Chile and
Patagonia, in a single localitj^ in South Africa (Basutoland), and in
various localities in Tasmania and in the Alps of New Zealand. Here
it would seem most likely that whilst South Africa derived the variety
across the ocean from Patagonia, the species reached Chile overland
from North America, and Tasmania from Central Asia, and that it
underwent the same varietal change in both those southern regions.

The conclusions to be formed from the outside connections of the
six South African species of Carex here concerned, are that four only
could have been derived overland from Europe, that one of them
probably hailed across the South Atlantic from Patagonia, and that
the sixth was perhaps Asiatic in origin. On the whole, it would
appear that South Africa has mainly derived its Carices overland
from the northern hemisphere.

(B) The Peat-mosses. — The South African Peat-mosses tell the
same story. Of the five species found outside the continent none
occur in either South America or in the Australian and New Zealand
region. Evidently South Africa has been stocked with its species
of Sphagnum from the north. Of these five species Madagascar
and the Mascarene Islands hold all. One of them, S. pappeanum^
which occurs on the mountains of East Africa, as on Ruwenzori,
has a most remarkable distribution. Outside the continent it has
been recorded only from the islands of Teneriffe, Bourbon, Rodriguez,
and Amsterdam.

The Mystery of Sphagnum pulchricoma. — Before quitting
this subject allusion should be made to the solitary Sphagnum con-
nection between the continent of Africa and the New World. This
is the more strange, since Africa, if we exclude the Mediterranean

DISTRIBUTION OF SPHAGNUM AND CAREX 347

Littoral, has no connection through the Peat-mosses with either
Europe or Asia. The species concerned is S. pulchricoma, which is
widely spread in America (United States, Equatorial Andes, Brazil,
Paraguay, etc.), and occurs also on the west side of Lake Tanganyika
in Central Africa. With the exception of its single African habitat
it is, as far as is known, exclusively a New World species.
Evidently before full weight can be attached to its sporadic
occurrence in Africa, the matter would require further elucidation.

Sphagnum and Carex in Australia and New Zealand. — There
is a good deal of parallelism between the behaviour of Sphagnum

Distribution of the Australian, Tasmanian, and New Zealand

Species of Carex and Sphagnum

Endemic
Species

Distribution of the non
Endemic Species

Species common to
Australia, Tasmania,
and New Zealand

Total number
of Species

Number

Percentage

Asia

Europe

North America

South America i

Africa (south)

Japan j

Australia, Tasmania,
New Zealand

Austraha, Tasmania

Australia, New
Zealand

Tasmania, New-
Zealand

Cajrex : —

Australia .

28

9

32

15

5

5

3

1

13

7

1

3

Tasmania .

9

5

3

2

3

1

5

7

1

1

New Zealand with
the islands .

42

27

64

10

6

6

5

1

9

7

3

1

New Zealand alone

41

24

59

10

6

6

4

1

9

7

3

1

Combined region .

61

40

66

18

8

8

6

2

15

Sphagxim: —

Australia .

24

13

54

6

5

5

1

6

3

2

Tasmania .

12

5

42

2

2

2

2

3

2

New Zealand with
the islands .

19

11

58

5

5

5

1

5

3

New Zealand alone

17

9

53

5

5

5

1

5

3

Combined region .

42

34

81

8

7

7

2

8

The above table illustrates three of the main features of the Carex and Sphagnum
floras of the Australian and New Zealand region —

(1) The degree of endemism ;

(2) The distribution of the non-endemic species outside the area concerned ;

(3) The connections between Australia, Tasmania and New Zealand, that is to

say, the number of species they have in common.

The southern part of South America.

348 PLANTS, SEEDS, AND CURRENTS

and Carex in the region of Australia and New Zealand, and there are
also some instructive differences. The principal features are shown
in the table given above. If we first take the combined region we
notice that whilst only 7 per cent, (three out of forty-two) of the
species of Sphagnum occur in both Australia and New Zealand, with
Carex 18 per cent, (eleven out of sixty-one) are recorded from both
regions. This would seem to indicate that Sphagnum has yielded
more than Carex to the differentiating influences; but the opposite
tendency is brought out in the table as respects New Zealand, where
Carex would appear to have a slight advantage in this respect. There
is little, therefore, to be gained by dwelling on this point.

In the case of New Zealand it makes no material difference whether
we include or omit the islands lying to the east and south (Chatham,
Antipodes, Campbell, Auckland, etc.). It should, however, be noted
that, as far as is shown in Kiikenthal's monograph, these off-lying
islands, as a rule, contain no species of Carex which does not exist
in New Zealand, the only exception being the Chatham Islands,
which alone in this region hold the Fuegian Carex darwinii. These
out-lying islands, therefore, are not known to possess any peculiar
species of Carex. It is different with Sphagnum, since Antipodes
Island and the Chatham Islands hold in each case a peculiar species
of the genus. In one or two cases the New Zealand Carices have
spread to Norfolk and Lord Howe Islands, thus indicating a tendency
to extend to Australia.

The column that is devoted to Japan in the table is merely in-
tended to emphasise the Asiatic connection. It is brought out in
the text that both Japan and Australia derive most of the species
held in common by them from the Himalayan region.

The Geographical Coxnectioxs of the Australiax axd New
Zealaxd Peat-mosses axd Carices. — But the difference between
Sphagnum and Carex in the Australian and New Zealand region is
only one of degree, since the geographical connections are closely
similar. Whilst with Sphagnum all of the eight species found outside
the region are Asiatic, seven being European, and seven North
American, with Carex eighteen of the twenty-one non-endemic
species are Asiatic, eight are European, and eight North American.
There is seemingly in both cases a connection between the Peat-
mosses and Carices of this region and those of the southern extremity
of South America. There is only a very slight connection with South
Africa in the case of Carex and none for Sphagnum. For genera so
unlike there is, therefore, at first sight a close correspondence between
their relations outside the Australian and New Zealand region, a
correspondence which is not lessened by an examination of the details.
Before discussing the predominant Asiatic connections, a feature
common to both genera, I will deal with the South American and
South African relations.

In the first place there is the South American connection, apparent
or real. As already shown in the case of Sphagnum, the two
Australian and New Zealand species {S. medium, -fimhriatum) which
occur in Fuegia are widely spread Eurasian and North American
species that could have reached their present homes in the south

DISTRIBUTION OF SPHAGNUM AND CAREX 34^

from Asia and North America, the postulate of a traverse of the
Southern Ocean being quite unnecessary. It has also been before
pointed out that of the six species of Carex, which Australia and
New Zealand possess in common with the southern part of South
America, four could have been derived from Central and South-
eastern Asia, and that the question of a South American origin
could only be raised concerning two species, C. darwinii and C. trifida.
Whilst it is highly probable, as previously shown, that the Chatham
Islands, its only locality in that region, received the first species from
Fuegia, the evidence respecting the second is indeterminate.

The connection between the Australian and New Zealand region
and South Africa is not illustrated by Sphagnum, and it affects only
two species of Carex (C. cernua and C. oederi); but it has already
been indicated that the evidence, though not decisive, tells more
against than in favour of a trans-oceanic connection, since the
original forms of both species could have reached the Australian and
New Zealand region from Asia.

The Asiatic Connections of the Australian and New Zealand
Region. — By far the most important are the Asiatic connections
of this region. As before remarked, all the species of Sphagnum
and nearly all the Carices that occur outside its limits are found in
Asia. There is no special connection with either Europe or North
America which is not also Asiatic, all the species so concerned being
widely distributed in the northern hemisphere. Asia, therefore,
represents the immediate source of the Australian and New Zealand
species of Sphagnum and Carex, since derivation from southern
South America and from South Africa is altogether excluded for the
Peat-mosses and for all but 3 or 4 per cent, (two or three out of
sixty-one) of the Carices.

When we examine the matter more closely, we find that all of the
outside species of Sphagnum and that fifteen of the twenty-one out-
side species of Carex occur in Japan, a fact that merely indicates a
common centre of dispersion in Central Asia for the representatives
of the genera reaching Japan and the Australian and New Zealand
region. Of the Himalayan region as the centre of departure from
which the same species has often travelled north-east to Japan and
south-east to Malaya and Australia, more will be said. The route
is determined in each case from the distribution of the species of
Sphagnum and Carex that are concerned. In the case of Sphagnum
there are four species — S. fimbriatum, papillosum, cymbifolium,
medium — that have found their way to either Australia or New
Zealand from South-eastern and Central Asia. All of them are
spread far and wide over the northern hemisphere in North America
and in Eurasia, and all have spread from the same Asiatic centre to
Japan as well as to the Australian and New Zealand region. The
two first named, however, present great gaps between their occur-
rence in the Himalayas and Burma and in New Zealand. The third
shows a similar hiatus between Southern China and New South
Wales, and the fourth between the Bhutan Himalayas and the Blue
Mountains in South-east Australia. But these gaps can be filled
up by other species that reach Japan and Malaya from the Himalayan

350 PLANTS, SEEDS, AND CURRENTS

region, but fall just short of Australia. Thus Sphagnum junghuh-
nianum is a Himalayan species that has arrived at Japan to the
north-east and at New Guinea to the south-east after halting in the
last case on the mountains of Java and Celebes. (On account of
its convenience the term " Malaya " is applied in this chapter to all
the region between South-eastern Asia and Australia.)

Bridging over the Gap in Malaya by the Carices. — The more
numerous data supplied by Carex enable us to bridge over the gap
usually presented by Spliagnuvi in the Malayan region, since one-
third of the eighteen Asiatic species found in the Australian and
New Zealand region are there represented. If we look at the twelve
Carices that jump over the Malayan Archipelago, we find that eight
are wide-ranging North American and Eurasian species; and, as
indicative of their capacity to reach as far as they can get, we notice
that all but one have traversed Eastern Asia and reached Japan,
four or five of these being recorded from the Himalayas.

The six Australian and New Zealand Carices that fill up the gap
in Malaya (C. rara, indica, rafflesiana, maculata, hreviculmis, brunnea)
are purely Asiatic, none being recorded from either Europe or North
America. They are most at home as denizens of warm latitudes in
southern and south-eastern Asia ; but they also illustrate in the case of
three of them (C. rara, brevicidmis, brunnea) how the same species of
Carex from a centre in the Himalayan region can reach Japan in the
north-east and Australia in the south-east. The distribution of C. indica
is illustrative of the track pursued by one of these Himalayan species
in reaching Australia. We can connect its habitat in Sikkim and
in Northern Australia with records from Assam, the Malay Peninsula,
Borneo, Java, and New Guinea. The case of C. breviculmis is also
interesting and suggestive. From an altitude of 10,000 feet in the
North-west Himalayas it passes across Assam to Tonkin and appears
on Mount Scratchley in New Guinea at an elevation of 12,200 feet
before making its way south to South-eastern Australia and New
Zealand.

These half a dozen Carices that halt in the Malayan region on their
way to Australia from South-eastern Asia include, as has been said,
three Himalayan species ; and in this connection it should be noted
that several other Himalayan Carices accompany them as far as the
highlands of Sumatra, Java, and Borneo, but no farther. I have
made from Kiikenthal's monograph a list of fourteen purely Asiatic
species (ten Himalayan and four from Southern India and Assam)
that have had their passage to the south-east arrested in Malaya.
They were, however, more successful in their passage to the north-
east, since half of them have reached Japan. But the point to be
specially noted here is that the Carices from the Himalayan heights
select similar great altitudes in Malaya. Thus C. filicina and C.
fusiformis, which have been recorded from elevations of 8000 to
12,000 feet in the Himalayas, have been collected on Mount Kinabalu
in Borneo at altitudes of from 9500 to 11,500 feet. So again,
C. teres, which occurs on the Sikkim Himalayas at an elevation of
8000 to 9000 feet, has been gathered on the slopes of the volcanic
mountain of Papandayan in Java.

DISTRIBUTION OF SPHAGNUM AND CAREX 351

Comparison of the Sphagnum and Carex Floras of Australia
AND New Zealand. — These remarks on the combined Australian
and New Zealand region may be supplemented by a reference to
the separate Sphagnum and Carex floras of the two subregions, as
exemplified in the table before given. As respects Sphagnum^
Australia and New Zealand when contrasted present much the same
degree of endemism. With Carex, however, the New Zealand
endemism is much more pronounced. As might be expected, the
Asiatic connections of the Australian Carices are more evident than
in the case of those of New Zealand; whilst the South American
connections are more apparent in New Zealand. But it will be
brought out below that these South American relations, as indicated
in the table, cannot be taken at their face- value, either for Australia
or New Zealand.

The Asiatic Connections of the New Zealand Carices. —
Of the ten New Zealand species displaying Asiatic connections, seven
are also known from Australia, viz. C. pyrenaica, stellulata, gaudi-
chaudiana, breviculmis, brownii, pseudocyperus, and pumila. Three
of these, the first, second, and sixth, are wide-ranging North American
and Eurasian species. The others are purely Asiatic, except the
last (C. pumila), which, though spread over Eastern Asia from
Manchuria to Hongkong, occurs sporadically in the New World in
Chile. It is discussed on p. 339. One of the most interesting of
these seven Carices is C. breviculmis. It is the only one of them that
breaks its journey from South-eastern Asia to Australia by halting,
as already observed, on Mount Scratchley in New Guinea at an
altitude of 12,200 feet above the sea.

Of the three Asiatic New Zealand species which have not yet been
found in Australia, Carex diandra, C. lagopina, and C. oederi, the last
named is recorded from Tasmania; and it seems not unlikely that
one or more of them will be discovered in the highlands of Eastern
Australia. All of them seem to pass from Southern Asia to Australia
without halting in the Malayan region; but one may expect that
some future explorer of the peaks of Sumatra, Java, and Borneo
will aid in filling up this gap. Of the three, perhaps C. lagopina
is the most interesting. This Arctic and Alpine species of North
America and Eurasia is a characteristic sedge of the Southern Alps
of New Zealand. The nearest Asiatic locality from which it has
been recorded lies in the Khasia Hills of Assam. No question of a
South American origin arises, since New Zealand exhibits its only
known habitat in the southern hemisphere. Carex diandra has a
similar distribution in the northern hemisphere; but it does not
occur in such high latitudes. It exists in both the North and South
Islands of New Zealand ; but there are great gaps separating it from
the Eastern Himalayas and Japan, its nearest recorded habitats.
Carex oederi is another North American and Eurasian species, which,
however, as already noticed, has a special variety (var. cataractce)
peculiar to New Zealand, Tasmania, South Africa, and extra-tropical
South America. The wide gaps separating New Zealand from the
nearest Asiatic habitats of the parent species in Kashmir and Japan
seem at first sight to point to a derivation across the Southern Ocean,

352 PLANTS, SEEDS, AND CURRENTS

a view supported by the distribution of the special varietj^ above
mentioned ; but this subject is further noticed in the next paragraph.

The South American Connections of New Zealand and
Australian Carices. — With regard to the apparently greater con-
nection with South America which is displayed by the New Zealand
Carices as contrasted with those of Australia, there is this to be said.
Of the five New Zealand species concerned, two, C. yseudocyperus
and C, pumila, are Queensland plants, which are found, the first in
Kashmir and the second in South China, so that it is scarcely requisite
to look to the southern part of South America for their source. Of
the other three species, C. darzvinii, trifida, and cederi, it has already
been said that the question of derivation from South America is
only imminent with respect to the first two, since they are found
nowhere else than in the New Zealand region and in the southern
part of South America. Whilst with C. trifida the evidence is in-
decisive, the probability is that the Chatham Islands received C.
dar-dcinii from Fuegia. The special variety of C. oederi, which has
often been mentioned as occurring in New Zealand, South Africa,
and southern South America, lends support at first sight to the
trans-oceanic hypothesis; but it is shoA\Ti that if put at all the
question should be narrowed down to the issue whether New Zealand
or South America is its original home, and preference is given to the
view that each of these regions derived the parent form from the
northern hemisphere, a corresponding varietal modification subse-
quently taking place in each region.

However, to be on the side of safety we assume that two of
the fifteen New Zealand species which are found outside that region
could have been derived from Fuegia. It is different with the three
species (C. canescens, pseudocy perns, and pinnila) that apparently
connect Australia ^^^th southern South America. It has above been
shown that the two last named probably reached Queensland from
Asia. As respecting C. canescens, the direct South American con-
nection is also excluded. It has been found in the mountains of
South-eastern Australia, though not in New Zealand. Like C. lago-
pina it is an Arctic and an Alpine species of the northern hemisphere,
both in America and Eurasia. Just as Fuegia received it from the
north by the way of the Chilian and Argentine Andes, so Australia
has received it either from Japan, or from the highlands of Kashmir,
where it has been found at an altitude of 12,000 feet. Looking
at all the facts concerned with the streaming of Carices to Australia
from Asia, it would be hazardous to assume that the mountains of
New South Wales and Victoria received Carex canescens across the
breadth of the South Pacific Ocean. On the whole, we may infer
that whilst New Zealand has derived two of its Carices from South
America, Australia has received none.

Similar Role of a Sphagnal Subsection in the Australian
and New Zealand Region and in Africa. — A supplementary
remark may here be made on a curious point of resemblance between
Africa and the Australian and New Zealand region. It has already
been noticed in the case of the African species of Sphagnum that the
isolation of the continent is to be associated with the fact that the

DISTRIBUTION OF SPHAGNUM AND CAREX 353

majority of species belong to the subsection Suhsecunda, which
possesses no world-ranging species. But this is not only a closed
subsection for Africa, it is the same for Australia and New Zealand.
Although it holds one-fourth of the Australian and New Zealand
species, they are all confined to the region, the species connecting
it with the outside world belonging to other subsections.

The Behaviour of Sphagnum and Carex and the Theory of
Differentiation. — If I were to endeavour to show how the be-
haviour of the Carices and the Peat-mosses, as discussed in this
chapter, fits in with the general theory of differentiation adopted in
the two preceding chapters, it would be, as briefly expressed, some-
what to this effect. The Carices represent one of the results of the
differentiation of a generalised cyperaceous type originally spread
over the globe; whilst the Cyperi represent another result. These
two genera largely compose the family, the second being as character-
istic of w^arm latitudes as the first is of the cool regions of the north.
Whilst the distribution of Carex has been mainly determined by the
divergence of the land-masses from the north and by the secular
changes of climate, that of Cyperus has been affected to a much less
degree by these influences. While the tide of the Carices has ebbed
and flowed in the north, the Cyperi could have reached the common
focus of dispersal in the Arctic polar area only when exceptionally
warm conditions reigned at the pole. Cyperus ought to represent
to some extent the attitude of relative passivity adopted by typical
plant-groups in the tropics. Its efforts to penetrate the cooler
regions of the globe have not been very successful ; whilst its sister
genus, Carex, has only been able to reach the temperate regions of
the south by halting on the tops of the mountains during its traverse
of the tropics.

It is the same with Sphagnum, since it is at home in the moors
of the north and occurs at high altitudes on the mountains of the
tropics. But there is evidence, as we learn from Ule as quoted by
Warnstorf (p. 33), that these plants are adapting themselves to a
low-level station in the tropics in the coast-plains of South Brazil,
We seem to know but little of the evolutionary history of a genus
which was raised by the elder Schimper to the rank of a separate
family; and it would be useless to evoke a differentiating process
that would involve the common origin from a generalised type of
the Peat-mosses, the Mosses proper, and the Liverworts.

One great lesson supplied by the striking parallelism of two plant-
types so widely divergent as Carex and Sphagnum is that time has
long since discounted any especial advantage which the one might
possess over the other as regards facilities for dispersal. In both
cases their distribution has been largely determined by the arrange-
ment of the land-masses and by the alternations of climate. Yet
such a parallelism would acquire but little importance, if it was
merely concerned with these two plant-groups. It indicates a
principle enunciated by Dyer as affecting a host of other plants of
the north, plants that are often strangely contrasted in almost every-
thing but their response to the principle of distribution so well
illustrated in the behaviour of Carex and Sphagnum.

A A

354 PLANTS, SEEDS, AND CURRENTS

The last great lesson it presents is shown in the support it gives
to the views of Bentham and Hooker on plant-distribution. It is
not easy to be original in any field where they have laboured. Though
the ground has been " pegged out " by them and others, the " claims "
are often still un worked.

Supplementary Note on the means of dispersal of the Carices and
the Peat-mosses : —

The Distribution of the Carices by Birds. — It will have been
noticed in the previous discussion that it has been assumed that species
of Carex and Sphagnum can follow along the length of the continents
from the north polar regions to Fuegia, South Africa, and Australia.
In the case of Carex it is well known that the hard seed-like fruits
occur in birds' stomachs, and it has been shown that the smaller
fruits can be carried in dried mud adherent to their feet and legs;
but the question arises whether birds do actually travel along the
routes that have been taken by these plants. It has before been
observed that certain South African Carices must have been derived
from the northern hemisphere, the possibility of their having come
across the ocean from South America, or even from Australia, being
excluded by their absence from those regions. This offers a critical
case, and to some extent we are able to meet it.

Thus, three instances have lately been recorded of swallows
captured in Natal and in the Orange Free State, which had been
" ringed " in Great Britain (Staffordshire and Ayrshire) nineteen,
nine, and four months previously (Scotsman, November 8, 1913;
Times, March 12, 1915). In the Times of the same date reference
is made to a Sandwich tern, " ringed " in England in July, which
was found on the Ivory Coast, West Africa, in the following February.
Then we have the numerous examples of storks marked in East
Prussia and the neighbouring provinces which were recovered in the
Transvaal, Natal, Basutoland, and Cape Colony. I am quoting here
from a paper by A. L. Thomson, who discusses in the Proceedings of
the Royal Physical Society of Edinburgh for March 1911, the results
of the German and Hungarian inquiries. Doubtless these facts could
he largely increased; but they are sufficient to show that birds do
:actually make periodical migrations from Europe to South Africa.

The Distribution of the Peat-mosses by the Winds. — It is
not unlikely that the spores of Sphagnum would be sometimes carried
in the dried mud adhering to migratory birds; but here the wind
presents itself as probably a more effective agent. This being so,
we are at once met with the question whether islands like the Hawaiian
tthat lie in mid-ocean some 2000 miles from the nearest continental
(Hoast, would have received their Sphagna through this agency. The
subject of the transport of seeds and spores by wind is discussed at
length by Mr. Lloyd Praeger in a recent paper in the Proceedings of
the Royal Irish Academy (1911), and I have dealt with it in this work in
connection with the Azores (Chap. XIX). Here it may be stated that,
as indicated by his experiments on the falling rate of seeds, even
the dust-like seeds of orchids could not be carried to Hawaii by a
wind moving fifty miles an hour unless they were raised at the start

DISTRIBUTION OF SPHAGNUM AND CAREX 355

to an altitude of fifteen or twenty miles. Although, therefore, this
would exclude all the flowering plants,even those with plumed seeds,
the matter assumes a different aspeet in the case of the spores of
cryptogams. Small as it is, the orchid seed may fall fifty times as
fast through the air as the spore of a mushroom ; and an initial eleva-
tion of at most 3000 feet would be needed for a successful traverse
by a mushroom spore of 2000 miles of ocean before a wind blowing
with a force of fifty miles an hour. This is the maximum altitude ;
but the average elevation required, as indicated by Buller's falling
rates given in the table in Chap. XIX, would be only half this amount.
Though I have no direct data for the Peat-mosses it is not probable
that their spores would require an initial elevation exceeding the
average height of a lofty mountain-range like that of the Andes, up
the slopes of which the ascending currents of air would be able to
carry cryptogamic spores to a suitable starting-level several thousands
of feet above the sea. (If the spores of Polytrichum could serve us as
a guide, the falling rates of which are given in the same table, the
initial altitude requisite for Sphagnum would not far exceed 1000
feet.) The occurrence of these up-draughts on the sides of high
mountains is well known, and the matter is dealt with afterwards.
In this manner the spores of cryptogams would be brought within
the influence of the upper air-currents and distributed far and
wide.

Summary

1. On finding that the Sphagnum floras of the eastern and western
hemispheres become more and more differentiated as one recedes
from the north polar region, the author turned to the Carices and
received the same reply. It was at the same time discovered that
in their distribution both genera reproduce many of the problems
which the plant-world presents in the case of islands and in the
floras of the great land-masses of the southern hemisphere. It also
appeared from the behaviour of Sphagnum that the lower plants
require a larger area than the higher plants for evoking the full
effects of the differentiating process, and that in this respect our globe
may not be large enough for lowly organised plants (pp. 332-4).

2. A table is given illustrating the effect of the divergence of the
land-masses from the north on the distribution of Sphagnum and
Carex. A comparison is then made of their behaviour in the North
American and Eurasian land-masses, and it is shown for both genera
that whilst the species common to both gather in the north, those
separately held congregate in the south. Thus it is indicated for
Sphagnum that 87 per cent, of the species common to both North
America and Eurasia are Arctic and Subarctic species. Of the
species separately held very few are found north of the temperate
zone. Thus in both the east and the west only 5 or 6 per cent, of
the species confined to the respective hemispheres occur in Arctic
or Subarctic latitudes. The Carices tell the same story in both
hemispheres, the proportion of species which North America holds
in common with Eurasia being 93 per cent, in the Arctic regions,
40 per cent, in the Subarctic regions, 24 per cent, in temperate lati-

356 PLANTS, SEEDS, AND CURRENTS

tudes, and 11 per cent, in the southern portion of the continent
(pp. 333-5).

3. The paralleUsm between Sphagnmn and Carex is strikingly
illustrated in the connections of South America with the rest of the
globe. In both genera there is the streaming of species from the cold
latitudes of the north along the line of the Rocky Mountains, across
the highlands of Central America, and down the Andes, reaching to
Fuegia (pp. 335-8).

4. The connections of South America with the Australian and
New Zealand region may thus be summarised. With both genera a
few of the species, that have reached the Southern Andes and Fuegia
from high northern latitudes have been found also either in Australia
or in New Zealand or in both. But whilst the two species of Sphag-
num concerned must have been received by each region from northern
latitudes on the same side of the globe, this can only be inferred for
three of the six Carices involved. The other three species probably
crossed the Southern Ocean, one from Fuegia to New Zealand and
another from Australia or New Zealand to Chile, the data for the
third being insufficient for the purpose of distinguishing between the
giver and the recipient (pp. 339-40).

5. The Carex and Sphagnmn connections between South America
and Africa are of the slightest. A single South American Sphagnum,
found also in North America, occurs in Central Africa; whilst a
single Carex, also North American and Eurasian, connects South
America with South Africa (pp. 341).

6. The African Sphagnum and Carex floras are then discussed;
and here again the behaviour of the two genera offers a striking
parallel, since they illustrate in a similar way that remarkable isola-
tion which iVfrica so often exhibits both in its flora and in its fauna.
Whilst the European species of Sphagnum have crossed the Mediter-
ranean only to reach Tunis and Algeria, the Carices from the north
have in nearly all cases been rolled back by the obstacles presented
by the Atlas and the Sahara, only a few penetrating to the south of
the continent (pp. 341-2).

7. Both genera display a like degree of endemism in Africa, ex-
clusive of the Mediterranean province, only about 20 per cent,
of their species occurring outside the continent. But in the case
of the Peat-mosses (Sphagnum) this cannot be taken at its face-
value. Whilst the Sphagna connecting South America and the
Australian region with the outer world range over much of the globe,
most of the African Peat-mosses that extend beyond the continent,
as here defined, do not reach further than Madagascar and the
Mascarene Islands. Africa possesses only one other link with the
other continents in a solitary North and South American species
that has apparently a limited distribution in the Lake District. As
far as the Peat-mosses are concerned, Africa compared with South
America and Australia is a lonely continent. As regards the African
Carices, although the proportion of species found outside the region
is about the same as in Sphagnum, the continent is brought more
in touch with the outer world by its connections, nearly all the species
concerned being wide-ranging Eurasian species that may in rare cases

DISTRIBUTION OF SPHAGNUM AND CAREX 357

include Australia and even North and South America in their range
(pp. 342-4).

8. With both Sphagnum and Carex more than half of the African
species belong to the youngest, most vigorous, and largest of the sub-
divisions of the two genera. Primocarex, the oldest subgenus of the
Carices and the nearest to the parent-type, fails altogether in Africa.
The facts indicate that the invasion of Africa by the Carices and the
Peat-mosses took place during the later stages of the differentiation
of those genera, and has since been followed by a period of isolation
extending down to the present time (pp. 344-5).

9. The sources of the Peat-mosses and Carices of the southern
part of the African continent are then considered, and it is concluded
that South Africa has derived all its Sphagna and most of its Carices
from regions north, it being shown that one of the last named was
probably brought across the ocean from Patagonia (pp. 345-6).

10. The parallelism between Sphagnum and Carex presented in
Africa and South America is also displayed in the Australian and
New Zealand region, the differences in the behaviour being only in
degree. Taking first the combined area and its connections with
South America, we find that the Sphagna concerned and most of the
Carices could have been derived from northern regions on the same
side of the globe (p. 347). The connection with South Africa is not
illustrated by Sphagnum and very doubtfully by two species of
Carex also found in Asia, which is probably their source (p. 349).
By far the most important are the Asiatic connections, which are
treated in detail ; but it may be here observed that all the Sphagna
and nearly all the Carices which are found outside the limits of the
combined area occur in Asia. There is no connection either with
Europe or North America that is not also Asiatic, all the species so
concerned being widely distributed in the northern hemisphere.
It is shown that derivation from South Africa and South America
is altogether excluded for the Peat-mosses and for all but 3 or 4
per cent, of the Carices, New Zealand having received two species
from South America and Australia none. Asia, therefore, repre-
sents the immediate source of the Australian and New Zealand
Sphagna and Carices (pp. 349-50).

11. The Sphagnum and Carex floras of Australia and New Zealand
are then compared ; and it is elicited that whilst the degree of endem-
ism in each region is apparently similar in the case of Sphagnum,
it is much more pronounced amongst the New Zealand Carices,
The respective connections are then discussed (pp. 351-2).

12. The similarity in the role played by a Sphagnal subsection
(Suhsecunda) in the African and Australian regions is noted
(p. 352).

13. An endeavour is then made to show that the general behaviour
of the Carices and the Peat-mosses is in agreement with the views
of distribution adopted in the two preceding chapters. The close
parallelism between genera so unlike in their rank, so remote from
each other in their histories, and so different in their modes of dis-
persal, is a pregnant fact in distribution. It indicates a principle
affecting a host of other plants of the north that are often strangely

358 PLANTS, SEEDS, AND CURRENTS

contrasted in everything but in their compliance with the laws of
distribution so well illustrated by Carex and Sphagnum (pp. 353-4).

14. Amongst subsidiary matters mentioned in connection with the
Carices and the Peat-mosses are those related to the insular factor
(p. 343) and the modes of dispersal (p. 354). The insular factor raises
other considerations than those specially dealt with in this chapter,
but it is observed in passing that both genera respond in like fashion
to the differentiating influences that are often intensified in oceanic
islands.

Note. — With reference to trans-oceanic dispersal in high southern
latitudes reference should be made to Note 37 of the Appendix,
where the distribution of Uncinia, a genus allied to Carex, is dealt
with.

3r 30°

27' 26° 25- 24- 23"

, Corvo(2548ft.)

Glares (3007 ft)

^ Graciosa. (1349 ft.)

(SSSonr^-^ ^anJorffe(3498fl)
(1613ft.)

lC:^^^SanMiguel (3570 ft.)

O Santa Maria, (18 70 ft)

27 * 26° 25" 24°

From the Admiralty Chart, No. 1855, based on the suruey of Captain Vidal in 1844, with small corrections to September 1913 as there stated. There is, houieoer, a more recent correction of 1914, the height of Pico Topo being given as 3357 feet instead of 5367 feet as in previous Charts.

Amongst the adaptations and additions made by the author are the inset plan of the Azores, the deletion of numerous soundings, the insertion of the approximate positions of the six fresh-uiater lakes, and several approximate elevations.
NOTE.—Hydrographically Pico and Fayal are one, since an upheaval of 300 feet would join them. Thus viewed, they are isolated by great depths from the other islands, by depths of 1000 fathoms from Florea and Corvo, of 700 fathoms from San Jorge, and of 1200 fathoms from San Miguel.
Whilst soundings of 900 fathoms are obtained about five miles off their southern aide, they are connected with the Azore Bank to the south-west by a ridge covered by a maximum depth of 300 to 400 fathoms.

JotD 3 artJuilomfn^ & Co. , ESiliT

CHAPTER XVII

THE AZORES

•B"„.t/aTo^t dle^^ptionV the those

Ir? forthe author's detailed account of his observations m the

^''it'i; not at all easy to obtain a general notion of the original flora
of these isla'ndr Much as has befn written ^^rea^lan^^^^
it is difficult to procure many data concerning the ;?^^f ^^^f^^^^fj^^^^

the mode of occurrence, and the f '^'T HochstetterWatso^^
exceDt from the earUer writings of Seubert, Hochstetter, vvatson

Ket Z others, the later works ^-"8. '"^^^Jf /^Ts^^^^^^^
catalogues of the species. Yet it is on the labours of the syste'natisU
that we rely for all safe progress m these ^^he mono^^^^^

of Seubert in 1844, of Watson in 1870, and f Trelease m 1897, torm
landmarks in the history of the investigation t^e fl°ra But
many have laboured to supply the materials, and her^ GodZ J
mention Guthnick, the Hochstetters (^^t^er and j>n) Godman,
Hunt C S. Brown, Sampaio, Carreiro, Machado, and Cha.ves.

The Ai^THOR's Sojourns in ™k Gboot -During his two
to the Azores, from the middle of February to the end of ApriU913
and from the middle of June to the middle of Augi^st 1914 the^^^^^^^
was nrincinallv engaged in investigating the altitudmal ranges oi
The pC:^ After fa^iUarising himlelf with the flora d^
of about three weeks on San Miguel, when he ascended the pnnc^P^
mountains of the island and enjoyed the '""^ p"n{^

extended to him by the officials of the Mumcipal Ito^seum at P^U
Delgada, of consulting the herbarium he v'sited P^o and remained
on its great mountain from the second week of March to the second
week of April 1913. During his second sojourn in the §^0"?^^
he stayed on the island of Pico from the end of June to t^^^
week of August, a period of six weeks, of which tbe first to»r were
passed on the mountain, and the last two "} the district of Caes o
lico and Praynha do Norte, lying off 'ts stopes. Jhe on^^^^^^^
island examined botanically was Terceira ; but this Jjit was conhned
to a single ascent of Santa Barbara, 'ts prmc pal summit. His
intention to spend some time on San Jorge, the only one of the larger

360 PLANTS, SEEDS, AND CURRENTS

islands of the group of which the botany is httle known, was frustrated
by the outbreak of the war.

His Ascents of the Cone of Pico. — Two ascents were made of
the summit of Pico, 7613 feet above the sea, namely, on April 1, 1913,
and on July 16, 1914 ; whilst several ascents to altitudes of between
5000 and 6000 feet were accomplished during both visits on the north,
east, south, and west sides of the peak, as well as numbers of excursions
on the lower slopes. A few words may be said here on the best
plan of exploring the mountain. The usual route to the summit
from Magdalena by the Serra, past the Lomba (5000 feet above the
sea), and up the south-west side of the cone, is the worst that could
be chosen by the botanist, since it does not bring him into contact
with the upper woods and provides insufficient opportunities of
examining the upland moors. The constant employment of this
route has been unfortunate for the botanical exploration of the
mountain, and largely explains how it came about that it was left
for the author to be the first to discover one of the most interesting
plants in the Azorean flora, in the form of Arceuthobium oxycedri^
a parasite on the Junipers all around the mountain. It also accounts
for the fact that certain plants, such as the Laurestinus (Viburnum
iinus), Hydrocotyle vulgaris, etc., which are rarely to be observed
along this route, were never accredited to Pico until his visit.

All routes to the peak from the west and south sides meet near the
Lomba, a prominent hill situated at the south-west angle of the foot
of the cone proper. It is from this corner that the easiest ascent
to the summit is made. But the top of the mountain can also be
reached from the east side. Though more difficult, this ascent was
effected, as I was told, by a man of San Joao many years ago.

For the botanist the best plan is to examine the southern slopes
from San Mattheus, the western slopes from Magdalena, and the
northern slopes from Bandeiras and Caes-o-Pico; whilst the easiest
way to explore the eastern, and especially the south-eastern slopes,
where the upper w^oods attain their greatest development, is to
avail oneself of a house used for cheese-making which is situated
about 2500 feet above the sea between Caes-o-Pico and San Joao.
The shortest route to the summit is from San Mattheus, and it is
one that does not involve a night spent on the mountain. By
starting in the early morning the traveller can reach home the same
evening after a prolonged stay on the top. Parties of young men
of San Mattheus make the ascent during the short summer nights,
and after viewing the sunrise return to their homes in time for their
day's work.

Though summer is naturally the most appropriate season, much
can be done by the botanist on Pico in the winter months, since the
woods are composed of evergreen shrubs and trees, and the usual
lower snow-limit encroaches but slightly on the wood-zone. But
in the winter half of the year, especially when snow lies on the peak,
it is difficult to procure guides to take one to the top. The bitterly
cold north winds, the heavy rains, and the prevailing cloud-cap,
are the chief obstacles at this season. I had to wait for several
days before I was able to induce my man to complete the last two

THE AZORES

361

thousand feet on April 1. Without informing him of my intention
to seize the first opportunity when we were exploring the lower
slopes of gaining the summit, I coaxed him on this occasion to an
altitude of 6000 feet, and the weather proving fine I completed the
ascent with the man following very unwillingly behind, the snow
offering but little difficulty.

It is the lack of warm clothes that mainly accounts for this un-
willingness on the part of the Pico islanders to make the ascent
in winter. Captain Boid observes in the work quoted below that
in winter the peak is " positively inaccessible on account of the
snow." This is incorrect. Occasionally in mid- winter a man is
sent up by a doctor to procure ice for some sick patient in the coast
towns and villages, but he generally returns with a tale of woe that
for a long time prevents others from attempting the venture. As a
fact, the ascent can often be made in winter ; but both the mountain
and the weather have to be carefully watched, the greatest danger
to guard against being the dense driving mists, when, as so often
happens, clouds gather on the higher slopes. Progress then becomes
impossible, and shepherds who have been tending their sheep have
perished from exposure.

I have never heard of any visitor to Pico making the ascent before
the month of May. Godman attempted it about the second week
of May after waiting for some days, but the weather prevented his
succeeding (Natural History of the Azores, p. 15). Though the Bullars
ascended on May \2 {A Winter in the Azores), that month is usually
regarded as too early in the year. Indeed, Boid, who was in this
locality in May 1831, states that he was prevented from ascending
the peak as he was informed that " the road to the summit was quite
inaccessible until June " (see his Description of the Azores).

Sketch 'of the Botanical Investigation of the Azores. —
Apparently, long 'before any systematic investigation "of the flora
of the Azores, several of its characteristic plants were introduced
into the gardens of Europe, more particularly those of Portugal
and England. In southern Portugal Myrica fay a is now " almost
indigenous " in the mountains of Algarve and in other localities,
and must have been brought from the Azores long ago, a matter
referred to in a later page. We learn from Alton's Hortus Kewensis
(1789) that this tree, with other plants from these islands, was
introduced in the Kew Gardens through the agency of Francis Masson
in 1777 and 1778. Although Masson was one of the first English
visitors to the Azores to display an active interest in the flora, a
paper by him in the Philosophical Transactions for 1778 on the
island of San Miguel contains but little botanical information. In
the middle of July 1775 George Forster took several excursions on
the island of Fayal during a stay of four or five days made by the
Resolution under Captain Cook. He gathered a small collection,
mainly consisting of weeds of cultivation and of other plants intro-
duced by man, the list of which is given in the Commentationes
Societatis Regice Scientiarum Gottingensis for 1787 (Vol. IX.). Further
reference will be made to this list when dealing with the introduced
plants. It is given in Note 33 of the Appendix.

362 PLANTS, SEEDS, AND CURRENTS

On April 24, 1838, there reached San Miguel a party of scientific
men, which included Guthnick, a native of Berne, Hochstetter and
his son Charles, and Gygax, a Swiss mineralogist. From the account
which Seubert gives in the preface of his Flora Azorica it appears
that Guthnick, after forming the project of investigating the little-
known flora of this group, received the advice of De Candolle, and
that the Hochstetters were his associates in the botanical exploration.
The party afterwards visited Terceira and Fayal, and here they parted,
the Hochstetters proceeding to Flores and Corvo in a vessel placed
at their disposal by Mr. Dabney, the American Consul-general,
whilst Guthnick during their absence returned to Europe. The
Hochstetters subsequently visited Pico and ascended the mountain,
and left the islands in August. I have not been able to discover
whether Guthnick published an account of his visit to the islands.
Some of his descriptions of new Azorean species are given in Seubert's
work. Among the botanical papers accredited to him in the Royal
Society Catalogue of Scientific Papers none are concerned with the
Azores. As regards the Hochstetters, it may be said that their
collections and notes formed the basis of Seubert's Flora Azorica
(1844). They worked out the zones of vegetation on the great
cone of Pico ; and it is to their labours that the scientific world was
first indebted for an accurate knowledge of the Azorean native
flora. Some of their principal results were first published in a sketch
of the flora entitled " Ubersicht der Flora der azorischen Inseln " by
Seubert and Hochstetter, which is given in Wiegmann's Archiv fur
Naturgeschichte, Berlin, 1843, a paper mentioned but not consulted
by either Watson or Trelease. It contains a large coloured plate
illustrating the zones of vegetation on the cone of Pico, the plants
characteristic of each zone being named. But the bulk of the work
of the Hochstetters was incorporated in Seubert's Flora Azorica,
which was issued in the following year, a work which held the field
until Watson's monograph appeared in 1870 in Godman's Natural
History of the Azores, and one that still stands foremost as an account
of the native flora.

H. C. Watson was the next botanist to visit the group. His stay
in the islands covered four months, from May to September 1842,
during which time he occupied a cabin in H.M.S. Styx, then engaged
in the survey of the archipelago. The exigencies of the survey
rendered the conditions by no means favourable for his purpose;
but he obtained collections from Corvo, Flores, Fayal, and Pico.
His examination of the mountain of Pico was restricted to an ascent
of the summit with the surveying party from the ship, and to two
other excursions on the lower slopes; but he expressly states that
the conditions did not allow him to obtain exact information con-
cerning the vertical range of the plants on the mountain. This
regret was expressed in a paper in the botanical publication below
named for 1843; and it is a pity that in his memoir in Godman's
work, published many years after, he depreciates the work of his
predecessors in this respect. In his criticism (p. 114) of Seubert's
Flora Azorica he gives as an instance of the " guesses that might
prove only erroneous records " the " alleged ranges of altitudes at

THE AZORES

363

which various of the species are stated to occur; but" (he continues)
*' it is asserted here with some confidence that the stated altitudes
must too often have been merely rough guesses by somebody not
sufficiently informed about the true heights of hills and places in the
Isles." Seubert's data were supplied by Hochstetter and his son,
and were by no means guesses. As shown in my notes on the Azorean
plants in Chapter XIX., they conform as a rule very closely with my
own independent observations, the methods of obtaining the altitudes
being there stated.

The results of Watson's investigations were first given in the
London Journal of Botany, 1843-7, and finally in 1870 in the botanical
section of Godman's general work. In the last case they were
greatly extended by a large amount of materials supplied chiefly
by collections made in 1844-8 by Mr. Carew Hunt, British Consul for
the Azores, and to a less extent by those made by Godman in 1865. It
may be added here that the Journal of the Royal Geographical Society
for 1845 contains a paper on the islands of San Miguel and Santa
Maria by Mr. Hunt. There is, however, not much in it of botanical
interest.

In 1857 there visited these islands Drouet and Morelet, two French
zoologists, and Hartung, a German geologist, of whom the two first
specially interested themselves in the botany of the group. Drouet
and Morelet were more or less associated in their travels, and they
remained in the islands from April to September. Morelet accom-
plished the ascent of Pico and made valuable observations on the
vertical distribution of the plants. Drouet attempted the same
ascent ; but his strength failed him, and he turned back when about
half-way up the mountain. Morelet published his notes in his
lies Agores (UHistoire Naturelle) in 1860. Drouet was rather more
ambitious, since he published in 1866 a list of the plants of these
islands in his Catalogue de la Flore des lies Agores. But, as Watson
points out (p. 119), his enumeration suffers from defects that were
to be expected in a work written by one whose chief speciality was
zoological. Yet with Drouet' s book in his hands the botanist
visiting these islands for the first time would be well provided, and
the mistakes arising from lack of familiarity with synonyms and
" name-changes " would be more than counterbalanced by the
valuable notes relating to the plants. Hartung, whose work on
the geology of the islands (Die Azoren, Leipzig, 1860) has long been
the principal authority on the subject, remained in the group until
the end of August. He seems to have made but a short examination
of Pico, and, though he visited all the islands, San Miguel and Terceira
occupied most of his attention. His book is chiefly of interest to
us from the observations it contains on the ancient trunks of Juniper
buried in the volcanic tuffs of San Miguel. He devotes about forty
pages to the flora, but he depends entirely on Seubert and Watson,
and in his comparison of the Azorean, Madeiran, and Canarian floras
he relies principally on Heer. It does not appear that he made many
observations on the living plants.

Excluding the Portuguese investigators, to be subsequently
referred to, the next person to interest himself in the vegetation of

^64 PLANTS, SEEDS, AND CURRENTS

the Azores was Godman, who, although his special mission was
concerned with zoology, made extensive plant collections during
his stay in the group, March to May 1865. These materials were in
part worked up by Watson in his monograph in Godman' s book on
the natural history of the islands. In 1894 Mr. C. S. Brown made
considerable collections, chiefly on Fayal, Pico, and San Miguel.
They were utilised by Trelease in the work to be immediately men-
tioned. Three months in the summer of 1894 and a shorter period
in 1896 were occupied by Trelease, Director of the Missouri Botanical
Garden, in making collections in these islands. They were worked
up by him and the results incorporated with those of his predecessors
in his Botanical Observations in the Azores, published in 1897 in the
Eighth Report of the Missouri Botanical Garden. The general
remarks are limited ; but as a catalogue of the plants this monograph
is the most complete and authoritative of the works on the Azorean
flora that have been published up to the date of my wTiting. In
March 1909, G. C. Druce made a brief stay on San Miguel, which
supplied materials for short papers in the Journal of Botany for
January 1911, and in the Chemist and Druggist.

The last to be mentioned, but not the least important of the in-
vestigators of the Azorean flora, are those resident Portuguese
gentlemen who in bygone and in recent times made numerous private
collections and built up the herbarium in the Municipal Museum
at Ponta Delgada. Much of the work of Dr. Bruno T. Carreiro,
Dr. C. Machado, Dr. J. A. N. Sampaio, and others is utilised by
Trelease in his monograph; but there must be many whose labours
have contributed to our knowledge of the plants of these islands,
though their names are no longer remembered. An account of those
of the earlier Portuguese residents, who in the long years since the
occupation of the islands have paid attention to the plants, would
come fitly from the pen of a Portuguese botanist. In 1852 there
was published at Lisbon a list of plants introduced into the Botanic
Garden of the Medical School of that city from various parts of the
world, the authors of which were B. A. Gomes and C. M. F. da Beirao
(Catalogus Plantarum Horti Botanici Medico- Chirurgicce Scholce
Olisiponensis). Azorean plants are here included. In conclusion
one may observe that in addition to his special studies on the general
zoology and fossil diatoms of the group. Colonel F. A. Chaves, the
head of the Meteorological Service of the Azores, has done much
not only in collecting flowering plants, but in assisting botanists
visiting the islands.

The Heights of the Azores. — The great volcanic cone of Pico,
7613 feet in altitude, is by far the highest mountain in the group,
none of the other islands attaining half its height. There are eight
other islands, and it is very remarkable that the three largest and
most elevated of them have practically the same elevation, San
Miguel 3570 feet, Terceira 3500 feet, and San Jorge 3498 feet ; whilst
the two islands next in size, Fayal and Flores, are not much lower,
their respective heights being 3351 and 3087 feet. This is a physical
feature of importance, since Pico loses the advantage of its much
greater elevation on account of the predominance of lava and cinders

THE AZORES

365

in its upper portion ; and for purposes of comparison, as concerning
the average soil-conditions suitable for vegetation, we may regard
only its lower 4000 or 4500 feet. Taking the whole island of Pico,
the same rule applies, since with the exception of the peak none of
the other mountains exceed 3500 feet in height. It is true that
Pico Topo, lying behind Lagens, is credited in the Admiralty chart
and in the accompanying " Sailing Directions " with an altitude
of 5357 feet; but there is an error here, the true elevation, as the
writer ascertained by aneroid, being about 3300 feet. This mistake
doubtless dates back to the time of the survey of the archipelago
by Captain Vidal, 1842-4. The author spent some days in the
vicinity of this mountain, which does not exceed the average height
of the peaks of this part of the island, the great cone towering far
above them all. He learned from Colonel Chaves that up to 1914
the Admiralty chart of the island was the only available map. (In
the latest issue of this chart (No. 1855) the correction has since
been made, the height of Pico Topo being there reduced to 3357 feet,
as indicated in the map of the island accompanying this work.)

Comparison of the Conditions of Forest-Growth in the
Azores, Madeira, and the Canaries. — From what has been said
above we should be safe in assuming that the soil- conditions for
typical forest growth in the Azores, as a whole, cease usually at
altitudes between 3000 and 4000 feet. It would seem from the early
accounts of Madeira that the original forests must have extended
nearly to the summit of the island, and we will take their average
limits as between 5000 and 6000 feet. In the Canaries, as illustrated
by Teneriffe, this limit would be generally about 7000 feet. After
applying to these values for the three Macaronesian groups the
correction for the difference in latitude and for the associated differ-
ences in climate, we should expect to find in the Azores only the
Canarian forest vegetation of between 2000 and 5000 feet, or, in
other words, the evergreen shrubs and trees of the Laurel-belt. We
could scarcely look for more, since the higher Pine-belt of Teneriffe
could not exist on the lava and cinders of the higher levels of the
cone of Pico ; whilst the lower Canarian coast-belt with all its strange
African plants would be unrepresented for want of the warm climatic
conditions. In Madeira, intermediate in latitude and in climate
between the other two groups, we should expect to find an inter-
mediate condition of things. The lower African zone, so well de-
veloped in the Canary Islands and absent from the Azores, ought to
be considerably restricted in Madeira; and, since this island barely
emerges from the cloud-belt, its forest vegetation of the Canarian
type might be expected, subject to soil-conditions, to reach the
summit. In this correlation of the three floras, the writer, as far
as the Azores and the Canaries are concerned, was long ago fore-
stalled by Hochstetter and Morelet. Its significance will be made
more apparent in a later page.

The General Profile of the Cone of Pico. — The characteristic
appearance of the great cone of Pico is that of a mountain rising
with easy slopes for its lower two-thirds, and then ascending pre-
cipitously to the summit. Except on the southern side it rises

366 PLANTS, SEEDS, AND CURRENTS

gently up to between 2000 and 2500 feet; after which there is a
steeper gradient to between 4500 and 5000 feet ; and then it ascends
rapidly to the top. Yet it would be difficult to find a lofty volcanic
mountain rising from the sea with such a steep slope as is presented
by the great mountain on its south side. It attains its maximum
elevation of 7613 feet at a distance of 2*42 geographical miles from
the coast, which represents an average angle of slope of about 27°.
Mr. Samler Brown rightly says in his guide-book to these islands
(edit. 1905, p. 7) that it rises more abruptly from the sea than the
Peak of Teneriffe. Taking the shortest distance from the coast
at seven and a half miles and the altitude at 12,180 feet, the Peak
of Teneriffe rises from the sea on its north side at an average angle
of about 15°.

There is some excuse for those who have coasted along the south
side of the island of Pico, or who have lived for weeks, as I have done,
on the south coast under the shadow of the peak, if at times they
carry away the exaggerated impression of a great cone rising in
places almost sheer from the sea. There lies before me a chart of
the Azores by Wm. Heather, dated 1822, drawn, revised, and cor-
rected by J. W. Norie, hydrographer. In a profile sketch of the
peak, bearing E. 3° S. by compass, the mountain is represented as
pinnacle-formed and rising from the sea to its summit at an angle
of about 60°. This, of course, is very far from being the case, as
may be seen from the profile sketches given in the Admiralty chart
from Captain Vidal's survey in 1842-4. Yet, as will now be shown,
there is a tremendous drop in a limited region on the southern
slopes.

The Bluffs of the Ribiera Grande. — Due south of the peak
and opposite the coast villages of Praynha do Sud and Terra do Pao,
the mountain in its lower half drops about 3000 feet in a thousand
yards, giving rise for a mile or tw^o to a line of huge bluffs, the pre-
cipitous faces of which are deeply scored by gorges and gulleys
forming dry river-beds, the largest of them being known as the Ribiera
Grande. Their steep sides, carved out into spurs and buttresses,
are usually well wooded, except in the gulleys and gorges, and they
terminate abruptly in the low and narrow strip of coast on which
the two villages lie. These bluffs constitute the most precipitous
portion of the lower slopes of the mountain and present one of its
chief spectacular features. The winding paths used by the shepherds
tending their sheep ascend what looks from a distance like an im-
possible precipice. Yet with a guide the ascent, though tedious,
is not difficult. Tiny white specks, which dot the upper declivities,
mark the sheep, and bring home to the climber the great height of
the bluffs.

Above the higher edge of the bluffs the steep upper slopes of the
mountain are streaked by " slides " of boulders and loose blocks
of lava, where no vegetation obtains a hold, localities that m}^ guides
were very un%\illing to approach. Not infrequently a huge boulder
is set in motion, and rolling down the slide it leaps over the upper
edge of the bluffs, and bounding down their precipitous sides at
tremendous speed, ultimately plunges into some field or garden at

I

THE AZORES

367

their base and comes to rest. To the people of the coast villages,
especially of that of Terra do Pao, which lies immediately beneath
the bluffs, the bombardment by boulders is a matter to be reckoned
with. They pointed out some to me which they declared had come
from the upper slopes of the peak. One of them was about three feet
high, and I was told that this size may be much exceeded. These rock-
masses, after leaping and bounding for at least 4000 or 5000 feet
down the steep mountain sides, sometimes come crashing down
into the precincts of the village in the middle of the night.

The Extent of the Vegetation on the Mountain of Pico. —
The impression formed at a distance that the lower two-thirds of
the mountain are vegetated and that the lava slopes of the upper
third are barren, is verified only in a relative sense when the observer
ascends the mountain. Godman (p. 15) remarks that " in winter
the extreme cone is frequently covered with a thin layer of snow,
and is destitute of vegetation with the exception of a few lichens."
Ogilvie-Grant, speaking of the Magdalena side of the mountain,
states that on the higher slopes " desolation and lava covered with
grey lichen and moss hold undisputed sway " {Nov. ZooL^ Jan. 1905).
Impressions of this kind are often acquired by those who have not
made the complete ascent.

The lower slopes are generally well vegetated up to altitudes of
4500 to 5000 feet, moor and grass land predominating in their higher
levels, that is, above 2000 feet. Woods are well developed in places,
the lower woods on the western side and the upper woods on the
south-eastern side. On the north-west side there is an almost
continuous band of wood, which extends from the vicinity of Ban-
deiras, about 400 feet above the sea, right up the mountain slopes
to over 5000 feet, where the trees and shrubs are dwarfed. The
woods are essentially formed by evergreen shrubs and trees; but
on account of the persistent agency of the woodcutter through
centuries the trees, except when specially preserved, rarely exceed
twenty feet in height, and are usually not more than fifteen or sixteen
feet. Dwarfing of the trees and shrubs begins as a rule at about
4000 feet as the effect of deficient soil and of exposure to the prevailing
strong winds; but it is likely that in the early times forests of
considerable height existed at this altitude.

Above the level of 5000 feet the sparse vegetation of the pre-
cipitous upper third of the mountain presents a great contrast to
the grassy and wooded slopes below. On the crumbling lava and
on the beds of cinders and coarse ashes that form the surface plants
for the most part obtain a scanty hold. It is true, however, that
dwarfed trees and shrubs climb the steep slopes for a few hundred
feet, the scrub failing at levels short of 6000 feet; but above that
height vegetation is sparse, and the plants become scarcer and scarcer
as one nears the summit, about half a dozen species reaching in
much diminished numbers the terminal crater and its small cone.

The Zones of Vegetation on the Mountain of Pico. — When
the writer visited Pico with the object of determining the altitudinal
arrangement of the plants, he was only acquainted with Watson's
and Trelease's monographs, issued respectively in 1870 and 1897.

368 PLANTS, SEEDS, AND CURRENTS

In the first-named work the subject is hardly mentioned, whilst
in the second it is not alluded to. After he had made his study,
he was surprised to find that excellent accounts of the vertical
distribution of plants on the mountain are to be found in the witings
of Hochstetter (1843), Seubert (1844), and Morelet (1860), and that
Drouet (1866) gave many details of importance. However, it is
to the Hochstetters that we are most indebted for information on
the subject. It was with mingled feelings of satisfaction and dis-
appointment that the writer discovered that his main results were
in close agreement with those of the German investigators and of
their later French fellow- workers in this field.

In the vertical range of the plants there are few material differences
between the writer's results and those of the previous investigators.
In the actual arrangement of the zones the differences are also few,
and in the main the suggested zones either confirm or amplify the
writer's own arrangement.

The zones on Pico, as first described in the conjoint paper by the
elder Hochstetter and Seubert in Wiegmann's ^rcAii; (1843), were as
follows : —

I. The cultivated or Mediterranean zone, extending from the coast
to an altitude of 1500 feet and characterised by Mediterranean and
European cultivated plants, weeds, and shore plants.

II. The Canarian zone, or belt of the Laurel woods, extending
from 1500 to 2500 feet.

III. The Azorean zone, or region of shrubs, 2500 to 4500 feet,
where many of the species peculiar to the Azores occur.

IV. The bush or scrub region, 4500 to 5000 feet.

V. The peak region, above 5000 feet to the summit (7600) feet.

There are one or two conspicuous defects in this arrangement.
In the first place, the Canarian zone extends considerably above
2500 feet. Then, any scheme that ignores the vegetation of the
upland moors, so prominent a feature on the slopes of the mountain,
between 2000 and 4000 feet, would be incomplete. The data, again,
scarcely justify our regarding the region between 2500 and 4500
feet as characterised principally by shrubs, or as being the special
home of peculiar Azorean plants. The coast, the lower woods,
and the upland moors, all present some of these endemic plants,
which number only about thirty in all, several of them having been
not yet recorded from Pico.

In Seubert's Flora Azorica, published in the following year (1844),
zones II. and III. are named respectively, the regions of the lower
and the upper mountain woods, a correction which makes the arrange-
ment closely similar to the one independently adopted by the present
writer, the characteristic plants of each zone being in close correspond-
ence. Here again, however, the belt of the upland moors is not
recognised. The arrangement, as given by Seubert, is based on
Hochstetter' s notes, and is as below given.

I. Region of cultivation, coast to 1500 feet.

II. Lower mountain woods, 1500 to 2500 feet.

THE AZORES

36^

III. Upper mountain woods, 2500 to 4500 feet.

IV. Region of bushes, 4500 to 5200 feet.

V. Highest zone, above 5200 feet, mostly lava, etc.

Morelet, in his work on the natural history of the Azores (1860),
adopts three zones of vegetation for the islands generally, namely : —

I. The zone of cultivation to 500 metres (1640 feet).

II. The middle zone, or the zone of woods, extending up to 1500
metres (4920 feet), and corresponding in the laurels and other ever-
green trees and shrubs to the laurel-belt of the Canary Islands.

III. The superior zone, 1500 metres to the summit. Here the trees
and shrubs become less vigorous and give place to the pastures and
the heaths. Only represented on Pico.

This is a good arrangement, though it is an error to place the
pastures in the third zone, the upland moors, to which he evidently
refers, belonging to his second zone.

The Zones of Vegetation on the Mountain of Pico as De-
termined BY THE Author. — We now come to the zones adopted
by the writer. As regards their limits there is a very close similarity
with those framed by Seubert from the notes of the Hochstetters
and given in his Flora Azorica. They were determined under the
belief that the present writer was the first to make this inquiry, and
their close correspondence with those adopted by Seubert enables
him to tread on firm ground in this matter. Before the occupation
of the islands the lower woods must have usually extended to the
coast, as they do now in places. Since it is with the native flora
and the original condition of the island that we are here concerned,
the region of cultivation is omitted and the belt of the upland moors
has been added. The list of plants, below given as most character-
istic of each zone, include all those named for the same zone by
Seubert and Hochstetter, with the addition of others.

I. The Lower Woods or the Faya zone, extending from the coast
to between 2000 and 2500 feet above the sea. The most abundant trees
are Myricafaya, Erica azorica, and Laurus canariensis (Persea azorica).
Next in order of frequency come Ilex perado, Rhamnus latifolius,
Persea indica, and Picconia excelsa, the last two being now rare.
Taxus baccata, at present almost extinct, found its home in the higher
levels of this zone. The most characteristic shrubs in their order
of frequency would be Myrsine africana, Vaccinium cylindraceum,
Hypericum foliosum, and Viburnum tinus, Hedera canariensis and
a species of Smilax represent the climbers, and Rubus fruticosus
occurs in the undergrowth. Osmunda regalis is the most conspicuous
of the ferns. Doubtless in the original forests this zone was divided
into two sub- zones by the distribution of the two laurels, Laurus
canarieiisis {Persea azorica) characterising the upper half and Persea
indica the lower half.

II. The Upper Woods or the Juniper zone, between 2000 and 4500
feet for the woods proper and from 4500 to 5500 feet for the scrub.
There is often a neutral area between 2000 and 3000 feet, where

B B

370 PLANTS, SEEDS, AND CURRENTS

the plants of the Faya and Juniper zones intermingle ; but as a rule
the Juniper begins where the Faya ends. The three most distinctive
trees and shrubs of this zone are in their order of frequency, Juniperus
oxycedrus (var. brevifolia), Daphne laureola, and Euphorbia stygiana,
the Tree-Euphorbia. But Erica azorica (Tree-Heath), Laurus
canariensisy Myrsine africana, Ilex perado, and Vaccinium cylin-
draceum, all of the lower woods, are here also abundant ; and charac-
teristic among the ferns are Dicksonia culcita and Acrostichum
squamosum, with Woodwardia radicans on the sides of the gulleys.
A common parasite on the Juniper trees is Arceuthobium oxycedri.
In the original forests Taxus baccaia thrived in the lower levels of
this zone.

III. The Calluna, Menziesia, and Thymus zone, 5500 feet to the
summit (7600 feet), the cone proper. Mats of Calluna vulgaris and
of Thymus serpyllum (var. angustifoliu^) and tufts of Menziesia
polifolia predominate on these scantily vegetated steep slopes of
lava and cinders. Polygala vulgaris also occurs with one or two
grasses, such as Agrostis castellana.

There is a close agreement between my predecessors and myself
as to the five plants that exist in the higher levels of the peak. All
of us, Hochstetter in 1838, Watson in 1842, Morelet in 1857, and the
writer in 1913 and 1914, record the Ling {Calluna vulgaris) and the
Thyme, and three of us the Polygala, the Menziesia, and the Agrostis.
The strangest reference is to the Polygala, which owes its occurrence
at this elevation to the protection it finds in the beds of Ling. A
solitary specimen was found by Watson in this locality (Lond. Journ.
Bot., II., 394) ; but the plant is frequent enough to be regarded as
one of the characteristic terminal species, and as such it was rightly
viewed by Seubert and Hochstetter.

Though the number of terminal species does not seem to have
increased in the interval between 1838 and 1914, it is likely that the
Ling, the Thyme, and the Menziesia have considerably extended
the area occupied by them on the level shoulder on the south side
of the mountain between 6500 and 7000 feet above the sea. With
the exception of Polygala vulgaris, all the plants of the highest levels
on Pico are widely distributed over the group. They are not neces-
sarily summit plants, but have found a home in the highest levels
because they alone of the plants of the lower levels, more especially
of the moors, have been able to establish themselves there. Polygala
vulgaris has been only found on the island of Pico, where it was collected
on and near the summit of the great mountain by Hochstetter in 1838,
by Watson in 1842, and by myself in 1914 ; but as below observed
I found it also on the moors below, as well as in those of the lake
district to the eastward. Agrostis castellana, as we learn from
Trelease, is a polymorphous Spanish species that is widely distributed
in the Azores, being the most abundant of the native grasses. It is
important to note that all the plants that have reached the top of
the great cone of Pico have climbed the slopes from the moors below.
There is no peculiar summit flora.

IV. The Upland Moors, 2000 to 4000 feet. This zone has been
formed at the expense of the Juniper zone around much of the moun-

THE AZORES

371

tain. Though doubtless greatly extended by the destruction of
the forests since the discovery of the islands, the moors have probably
always formed a conspicuous feature of the mountain of Pico around
the base of the steep-sided central cone. Without differentiating
here between the drier and wetter areas, the most striking features
are the bracken (Pteris aquilina), the large tussocks of Polytrichum,
and the beds of Sphagnum, Their general characters are often
those of a Devonshire moor, as on Dartmoor; and most of the
characteristic species exist in both regions. Amongst the most
frequent flowering plants are Anagallis tenella, Calluna vulgariSy
ErythrcEa massoni, Hydrocotyle vulgaris, Luzula purpureo-splendens,
Lysimachia nemorum (var. azorica), Menziesia polifolia, Poly gala
vulgaris, Potentilla tormentilla, Sibthorpia europcea, Thymus serpyllum
(var. angustifolius), Viola palustris, and among the sedges, Carex
flava. Lycopodium selago is common, and Blechnum spicant also
occurs. Water-holes exist in the more boggy ground, and around
the edges and in the water of these pools grow Callitriche aquatica,
Carex stellulata, Littorella lacustris, Peplis portula, Potamogeton
polygonifolius, Scirpus fluitans, S. multicaulis, etc.

The Prevailing Climatic Conditions on the Upper Slopes
OF THE Mountain of Pico. — With regard to this point it may be
stated that the cloud-belt or rainy zone, 2000 to 5000 feet, corresponds
roughly to the Juniper zone and to the belt of the upland moors.
The " region of clouds," as Watson terms it, is suggestively described
by him as the region of boreal and marsh plants (Lond. Journ. Bot.,
II., 394). With reference to the higher levels between 6000 feet and
the summit (7600 feet), although the nature of the surface of crum-
bling lava and cinders would primarily determine the type of plants
adapted for growing on steep slopes of this character, the choice
would be further restricted to plants capable of withstanding in
such an exposed situation the relatively dry atmosphere, the fierce
rays of the sun in summer, the frost and snow of winter, and the
stormy winds that buffet these heights during much of the year.

Whilst the rainfall would be much less on the high levels than in
the cloud-invested Juniper zone and upland moors below, its de-
ficiency would be partly compensated for by the heavy dews. The
amount of sunshine must be considerably greater here than in the
zones of the woods below. The mere concealment of the peak by
clouds, when viewed from the coast, by no means always implies
that the summit is cloud-capt. Not infrequently, when the writer
had reached the upper limit of the cloud-belt through a driving
w^et mist, he found the upper third of the mountain exposed under
a clear sky to the full glare of the sun and rising out of a billowy
sea of clouds of dazzling whiteness, like an island in the midst of
Arctic snows.

Although the daily range of temperature would be greater, it is
very probable that the monthly means of the temperature of the air
in the shade on the higher slopes of the mountain would approximate
those for the elevated region of Dartmoor in the south-west of England,
between 1500 and 2000 feet above the sea, a range, let us suppose, of
from 33° in January to about 58° Fahr. in July. Snow comes and

372

PLANTS, SEEDS, AND CURRENTS

goes on the peak at intervals during the winter and may He for
some time ; but it is rarely of any great depth except in the drifts.
As a rule it disappears finally during May. Godman (p. 10) speaks
of the sno^w top of Pico peeping out from the clouds in the last
week of April (1865). The statement of Captain Bold (pp. 307-9)
that snow lies on the mountain nearly eight months of the year
gives an exaggerated notion of the permanency of the snow-cap on
Pico. Watson observes that snow may lie under the shade of rocks,
and (one may add) in cracks and fissures, until May, but no longer.
He states that six weeks before his ascent on July 1 Mr. Dabney
had sent a party up to procure snow for a sick friend, " and they
got some {Lond. Journ. Bot., II., 39-4).

The lower limit of the snow is generally about 4000 feet ; and in
this connection it should be noted that on the summits of the other
large islands, all of which reach a height of about 3500 feet above
the sea, snow rarely lies. It is always winter for the people of the
Western Azores, whilst Pico wears its white cap. During the -^Titer's
stay on the mountain, from the second week of March to the second
week of April 1913, snow fell on at least three occasions, and for
most of the time the peak was white ^\\\.h. it. Different ascents
were made up the snow-covered slopes, and in one of them (April 1)
he gained the summit.

General Account of the Vegetation of the Mountain of
Pico. — Coming to a general account of the vegetation of this great
volcanic cone, and reversing the customary order of description, we
will imagine a botanist who, after alighting on the top of the mountain,
descends to the coast. Upon the summit, not only at the borders of
the small crater, but also on the sides of its little cone (200 feet in
height), he would observe in the crevices of the bare lava surfaces
small stunted gro\^i:hs, only a few inches high, of Calluna vulgaris
and Menziesia poIifoUa, with small patches of Thymus serpyllum
(var. angustifoUu-s), and here and there a tuft of Agrostis castellana.
Proceeding to descend the lava slopes on the south side he would
very soon notice specimens of Polygala vulgaris growing for protection
in the patches of Ling {Calluna vulgaris). He quickly reaches the
shoulder of the mountain, a more or less level stretch of lava and

lapilli," 6500 to 7000 feet above the sea, where the Ling and the
Thyme grow in dense mat-like beds, almost carpeting the surface
in places, the first named only a few inches high and scarcely higher
than the Thyme beds. In the middle of July the Ling shows only
the evidence of the last season's flowering and fruiting, whilst the
Thyme beds present a mass of bloom. It is on this shoulder of the
mountain that St. Dabeoc's Heath {Menziesia polifolia) is most
abundant, and flowers copiously in July.

[The above description applies to the plants of the summit as
observed by the ^\Titer in the middle of July. When he ascended
to the top on April 1 of the previous year, the peak was largely covered
with snow ; but the beds of Ling and Thyme were easily recognised,
the former plant displaying the bleached sepals of the last season's
flowering and the latter retaining in abundance the empty fruiting
calices.]

THE AZORES

878

From the edge of the shoulder one looks down a precipitous slope
of lava-flows, loose stones, and ashes, covered in places by large
patches of the Ling, Thyme, and St. Dabeoc's Heath. One instinc-
tively treads on the mats of Ling and Thyme, since they give a
firmer foothold during the steep descent. There are few other
flowering plants, except the half a dozen above named, that grow on
these arid slopes above 6000 feet.

Very rarely one comes upon some straggler from the woods below
growing from seeds dropped by birds in the crevices of a bare lava-
cliff. Situated far above the ordinary upper limit of the rain-belt,
exposed to the frosts of winter, and unprotected against the in-
tensity of the sun's rays in summer, such a plant has a hard struggle
to hold its own. It was under such conditions, at an altitude of
6300 feet, that the writer found in the middle of July a few scattered
individuals of the Azorean Holly (Ilex per ado). Though they were
scarcely over a foot in height, their thick woody stocks indicated
that they had been established for some years. They were in bloom ;
and it was interesting to notice how the axillary flowers were protected
against the scorching heat of the sun's rays by the raising of the leaves,
which had assumed the vertical position and lay with appressed
faces close to the stem. The expanding terminal leaf-buds were
shielded by the same device ; but more often than not it had proved
to be ineffectual, and the buds were blackened and dead.

Our botanist has now descended to an altitude of about 6000 feet.
Before he gets off the steep upper-third of the mountain on to the
wooded and grassy slopes of gentler gradient below, he has yet to
clamber down another thousand or fifteen hundred feet over old
lava-flows, beds of cinders, and loose stones and boulders that when
displaced bound for hundreds of feet down the mountain's side.
But, as he descends, the conditions become a little more favourable
for plant growth. For a minute or two a driving mist envelopes
him and shuts all out from view. He has been in a wisp of cloud
and is approaching the upper limit of the rain-belt.

Should he descend on the western side he will make but few
additions to his list of plants, until, at a level of about 5500 feet,
he comes upon the outposts of the woods in the form of stunted
bushes of the Tree-Heath (Erica azorica). On the eastern slopes
of the mountain, where for some reason more humid conditions
prevail, as soon as he passes below 6000 feet he will find that the
beds of Ling (Calluna vulgaris) afford protection to a variety of
different plants. On these wind-swept slopes the Ling beds are
only four or five inches high ; and in them nestle dwarfed specimens
of Jiiniperus oxycedrus, flowering and fruiting, though not over
six inches in height, as freely as the trees of ten and twelve feet in
the woods below. On exposed peaks in this group, as may be
observed on the summits of San Miguel, Terceira, etc., one often
finds a dense spreading growth of stunted Junipers rising only two
feet from the ground, a feature also observed and well described by
Watson (p. 224); but nowhere did the present writer notice the
dwarfing process so pronounced as in the case of these tiny Junipers
fruiting in the Ling beds on the bleak heights of the great mountain

374 PLANTS, SEEDS, AND CURRENTS

of Pico. Amongst the other flowering plants that find a sanctuary
in these Calluna beds at altitudes of 5000 to 6000 feet are delicate
herbaceous plants, like Polygala vulgaris, Erythrcea massoni, and
Lysimachia neynorum, and a hardy plant like Vaccinium cylindraceum,
which, however, instead of growing nine or ten feet high, as in the
woods, is here reduced to five or six inches. Of the ferns and lycopods
that are able to hold their own at these high levels of 5000 to 6000
feet, Blechnum spicant takes refuge in the Ling beds, whilst Ly co-
podium selago seeks a shelter in the hollows of the lava.

The impression one forms while descending these steep lava
slopes of the upper-third of the mountain is that many of the plants
characteristic of the lower levels would reach the summit, if the
soil- conditions allowed it. This was also the opinion of Morelet,
the French zoologist, who ascribed the penury of the higher levels
to the nature of the surface and to the steep angle of the slopes.
The repressive influence of the fierce winds that blow around these
heights during much of the year would be mainly found in the dwarf-
ing of the trees and shrubs. That several of the plants which are
at home in the upper woods between 2000 and 4000 feet can grow
at levels between 5000 and 6000 feet is sho^vn in their readiness to
seek shelter at these heights in the small craters and gulches, in
the broken-down lava caverns, and in the numerous fissures, cracks,
and holes. Here we find the Tree-Euphorbia {E. stygiana), the
Azorean Holly (Ilex per ado), Daphne laureola, Myrsine africana,
Laurus canariensis, etc., species that are not to be seen on the wind-
swept slopes near-by; whilst the Juniper and Vaccinium may be
observed growing four or five feet high in a pit and only four or five
inches high when exposed at its borders.

But apart from these sanctuaries on the higher slopes for the more
adventurous plants of the woods below, stunted specimens of the
Tree-Heath (Erica azorica), which form the outposts of the woods,
sometimes ascend, as already observed, the lower slopes of the steep
upper-third of the mountain to between 5500 and 6000 feet. When
we get off these steep slopes at a level of from 4500 to 5000 feet,
the soil-conditions become more favourable. Here the Tree-Heath
begins to assert its arborescent habit, and it is associated with Juniper
trees of fair size, the Juniper growing well on suitable ground at
these altitudes.

We now enter the cloud-belt, or rainy zone, which in its limits
of 2000 to 5000 feet rudely corresponds to the upper mountain
woods. Amongst the trees. Erica azorica is often predominant,
attaining its greatest development in the middle of the belt and grow-
ing, when left undisturbed, to a height of fifteen, eighteen, and even
twenty feet ; while in the open woodland bushes of Calluna vulgaris
may be nearly as abundant. It is between 3000 and 4000 feet that
the upper woods display their best growth, and this is well seen
on the south-east slopes of the mountain. Although on account
of the woodcutter's destructive influence, exercised through cen-
turies, the wood is small, the height of the trees not usually exceeding
fifteen or sixteen feet, several of them when left alone can attain,
as below shown, twice this height. Among the other characteristic

THE AZORES

375

trees and shrubs of the upper woods are Laurus canariensis, Myrsine
africana, Ilex perado, Daphne laureola, Vaccinium cylindraceum,
etc. ; and here thrive as soHtary specimens, or in twos and threes^
the Tree-Euphorbias (E. stygiana).

Indications of the prevailing humidity in the upper woods are
displayed in the filmy ferns (Hymenophyllum tunbridgense) growing
on the trunks of the large Junipers and Tree-Heaths. In the rank
undergrowth flourish ferns like Dicksonia culcita, Acrostichum
squamosum, and the Bracken (Pteris aquilina), lycopods like Lycopo-
dium complanatum, and flowering plants, such as the beautiful
Euphrasia gratidiflora and Carices, among which we may mention
Carex stellulata. Woodwardia radicans is conspicuous amongst the I
ferns that drape the sides of the gulleys; and clothing the moist
and shady banks of the small stream-channels are the fronds of
Trichomanes speciosum. Covering the walls of the lava caverns are
SelaffinellcB and Hepaticce.

When long undisturbed these upper mountain woods form dense
thickets difficult to penetrate. Here thrives on the branches and
trunks of the Juniper trees the Loranth, Arceuthobium oxycedri,
a parasite that grows commonly on these trees all round the slopes
of this mountain at elevations of from 2000 to 4000 feet. One little
plant not yet mentioned is Sibthorpia europcea. It abounds in shady
spots.

One of the most interesting of the plants in the upper woods is
Daphne laureola, which is usually restricted to levels between 3500^
and 4500 feet. In the woods and thickets it displays a loose strag-
gling habit; but when, as on the northern side of the mountain^
it grows exposed on the moors near their upper limits, it presents
itself as rounded dense bushes three or four feet in height. Yet it
is a plant that even here seeks protection, and it selects the dips-
and hollows of the moors and gives a singular appearance to the.'
landscape.

Numerous small craters and gulches in the zone of the upper
woods afford refuge to plants that under ordinary circumstances
are confined to the lower woods. The vegetation of the small craters
on the slopes of this mountain is often especially luxuriant. When,
as sometimes happens, the crater or gulch is inaccessible, the plants
attain unusual heights, protected against injury from men and
animals. Here in a limited space, at altitudes of about 3500 feet,
one may observe nearly all the trees and shrubs of the slopes of Pico
from the coast up to 5000 feet, not only those of the upper woods,
but such as Myrica faya, Rhamnus latifolius, and Viburnum tinus,
that are ordinarily restricted to the lower woods. In these refuges
the Tree-Euphorbias are especially at home, and there flourish
here many herbaceous plants of both wood zones, such as Euphrasia
grandiflora, a tall Verbascum, Sanicula azorica, and species of
Habenaria.

The dominant trees of the lower woods, that is, below 2000 feet^
are Myrica faya, Erica azorica, and Laurus canariensis. The
dominant shrub is Myrsine africana. But Rhamnus latifolius,
Vaccinium cylindraceum, and Ilex perado are also frequent. The

S76 PLANTS, SEEDS, AND CURRENTS

Laurestinus (Viburnum tinus) is absent in some places and fairly-
represented in others. The " Pao branco " (Picconia excelsa) is
now very rare, its timber being much appreciated by the islanders.
However, single trees may occasionally be noticed in the woods;
but as a rule it finds a refuge in some inaccessible gulch or small
crater. Osmunda regalis may be observed at levels exceeding 1000
feet in moist surroundings at the margin of the woods. Amongst
the tree-climbers are a Smilax and Hedera canariensis, the undergrowth
being generally formed by species of Rubus, Myrsine africana, the
Ivy just named, and Pteris aquilina. In the open districts Calluna
vulgaris is abundant.

But the lower woods are essentially the zone of the Faya tree,
and here, as in the case of nearly all the most conspicuous features
an the vertical distribution of plants on this mountain, we have the
corroborative testimony of the Hochstetters. Just as the Junipers
are restricted to the upper woods, so Myrica faya is characteristic
of the woods below, and rarely extends much above 2000 feet, except
when it finds shelter in some gulch or small crater as before described.
The trees of the lower woods that reach the coast are mainly the
Faya and the Tree-Heath (Erica azorica). Two plants range through
the whole height of the mountain, Calluna vulgaris and the narrow-
leaved variety of Thymus serpyllum. They grow not only on the
old lava-flows as they reach the coast, but also on the lava surface
of the summit, and on various kinds of soil, both rich and poor, in
the intervening levels.

The Vegetation of the Upland Moors of the Mountain of
Pico. — There remains for consideration the vegetation of the upland
moors, which are generally confined between the levels of 2000 and
4000 feet. The moors form a belt around the greater part of the
mountain, but are crossed at intervals by broad strips of woodland.
Lying as they do within the rainy zone, their conditions are nearly
as moist as those of the upper woods, and they largely usurp their
place. They are used as pasture-land for cattle, the lower portions
being under private ownership, while the upper parts marked off
by a high wall, usually about 3000 feet above the sea, are known as
the Baldios or Common-lands. These upland moors, which doubt-
less have been greatly extended by deforestation since the colonisa-
tion of the group, are characteristic of all the larger islands. In their
general features and in the association of their plants they often
display, as already observed, a striking resemblance to Dartmoor.

Their surfaces on the slopes of this mountain are often marked by
linear copses of the Tree-Heath, which present a variety of strange
patterns, that look from a distance like huge hieroglyphs on a light
green ground. Two objects have here been served. In availing
himself of the natural growth of the trees, the land-owner has so
trimmed and directed the growth of the original copse, that at the
expense of as little ground as possible he obtains shade for his cattle
in summer and shelter from the cold winds in %vinter. In the other
case, whilst clearing his land he has preserved the heath trees,
when they are frequent, near his boundary lines, and has allowed
them to propagate themselves only on the borders of his property,

THE AZORES

377

the result being that his land is partially enclosed in a living
tree-fence.

Except on the south side, where the mountain rises steeply from
the coast to its summit, these upland moors have generally an easy
slope. The bracken (Pteris aquilina) and the tussock of Polytrichum
give a character to their rolling grassy surfaces. It is pleasant to
tread their springy turf after the rough descent of the precipitous
and scantily vegetated lava slopes above; and, if it is summer,
the multitude of herbaceous plants in bloom will delight the eye.
One may on the western side distinguish between the boggy lower
areas, where Sphagna flourish, and the relatively drier upper levels,
where Peat-mosses do not live ; but more often this differentiation
is not to be made, and one may stumble on a bed or a pocket of
Sphagnum without much warning.

On the drier ground thrive Erythrcea massoni, Lysimachia nemorum
(var. azorica), Luzula purpureo-splendens, Menziesia polifolia, Poly gala
vulgaris, Potentilla tormentilla, and Thymus serpyllum (var. angusti-
folius). Calluna vulgaris forms an occasional scrub, whilst Sibthorpia
europcea conceals with its foliage the shady side of pits and holes,
though with the species of Lysimachia it is almost as common in
the wetter areas. Terrestrial orchids {Serapias, Habenaria) are not
infrequent, and the turf is dotted with single tufts of Lycopodium
selago, while Blechnujn spicant grows in the higher levels.

The wetter areas, when of any size, are essentially Sphagnum
moors, and the Polytrichum tussocks are here more numerous and
larger, and measure one and a half to two feet high and two to three
feet across, the Peat-mosses being often closely associated with them
in their growth. Anagallis tenella, Hydrocotyle vulgaris, and Viola
palustris grow in great abundance, and among the Carices, Carex
flava is the most common and sometimes almost monopolises the
ground. It may be doubted whether the Bog Pimpernel (Anagallis
tenella) exists in greater profusion in any part of its range than on
the island of Pico. The WTiter has walked for miles on the mountain
moors to the east of the peak, treading on its flowers at nearly every
step. In the tussocks, or rather hummocks, of Polytrichum, almost
all the flowering plants of the wet moor in turn find a home; but
Hydrocotyle vulgaris is most frequently to be noticed growing in their
midst. The tussocks, by becoming confluent, form in places dense
beds nearly appropriating the ground. This is to be observed at
altitudes of 5000 feet on the north side of the mountain, where the
moor vegetation begins to ascend its steep upper-third.

The Sphagnum growth is in some localities very extensive, as on
the south-west side of the mountain between the Serra Gorda and San
Mattheus. For one and a half or two miles from the Serra the soil
is stoneless and peaty, and Sphagna form dense growths, a foot
high or more, around the bases of the shrubs of Erica azorica that here
clothe the surface. The bushes, in fact, seem to grow out of Sphag-
num tussocks. The signification of this association is not very
obvious. Tansley in his Types of British Vegetation (1911, p. 235)
describes similar growths of Sphagna around the bases of bushes and
on the stools of Phragmites in the fen formation of East Norfolk,

378 PLANTS, SEEDS, AND CURRENTS

and he considers that the acids secreted by the Peat-mosses would
be neutraUsed by the alkahne ground- waters. In the coastal swamps
of the Carolina region a large fern, Woodwardia virginica, grows out
of low Sphagnum tussocks which are surrounded by standing water
(Harshberger's Phyt. Surv. N. Amer., p. 441). The Pico locality,
it should be noted, lies in the midst of a district of basic lavas, rather
over 2000 feet above the sea. In midsummer its surface is but
slightly moist, and large masses of dead Peat-mosses are seen. In
winter the ground would doubtless be very wet.

Here and there water collects in depressions of the boggy ground
on these upland moors. Around the edges of the pools grow Littorella
lacustris, PepUs portula, Carex stellulata, and Scirpus multicaulis,
the last in proliferous condition. In the water thrive Callitriche
aquatica, Potamogeton polygonifolius, and Scirpus fluitans. Watson,
in his paper in the London Journal of Botany for 1843, gives a list
of the plants growing in and around some of these pools on the upland
moors which he passed on his way to the summit. They include
Callitriche verna, Carex stellulata, Peplis portula, Potamogeton natans
(subsequently referred to P. polygonifolius), Scirpus fluitans, and
Sc. savii. Further remarks on the aquatic and sub-aquatic plants
of the island of Pico will be found in the following chapter.

The Secondary Cones on the Slopes of the great Mountain
OF Pico. — Reference has more than once been made to the craters
of these numerous small cones as sanctuaries for plant life. They
vary usually from 50 to 250 feet in height, and as far as could be
gathered show no signs of volcanic heat, their interior as well as
their exterior slopes being either grassy or wooded. Many of them
are situated in the upland moors or in the zone of the upper woods,
that is to say, at elevations of from 2000 to 5000 feet above the sea.
In some instances the craters are inaccessible, and in one case, where
a narrow gap led into the crater, the interior was once used as a
corral for cattle. I ascended many of them, and the vegetation of
their outer slopes depends on whether they rise up in the moors
or in the woods. Their craters are usually dry, and only in the case
of the smallest cones do they hold shallow ponds, the abode of aquatic
plants. In one such crater pool Potamogeton polygonifolius grew
in the water and Scirpus multicaulis at its sides, there being a growth
of Sphagnum at its border. (In the case of the numerous crater
lakelets, that occur off the great mountain in the eastern part of
the island, a few remarks will be made later on in this chapter.)
Some of the cones are very regular in form, and one may mention
in this connection the Cabeza Norte, which lies at the foot of the
cone proper on its W.N.W. side about 4000 feet above the sea.
It has a height of 200 feet, and its crater, which is remarkably
symmetrical in shape, is 500 feet across and is as deep as the hill is
high. Its interior is partly clothed with shrubs, mostly Erica
azorica, with a little Ilex perado.

The Lake District of the Island of Pico. — This region is
separated from the eastern slopes of the great mountain by a broad
saddle, or elevated plain, which is raised not less than 2000 feet
above the sea. The plain is dotted with small volcanic cones, and

THE AZORES

37^

is in part grassy and in part boggy, cattle grazing here in numbers.
To the east of it Hes the mountainous eastern part of the island,
with which I became acquainted as far as Santo Amaro on the north
coast and Ribeiras on the south coast. The general level of this
upland region is 2500 to 2800 feet, and from it rise abruptly several
isolated peaks, the highest having an altitude of about 3500 feet.
Numerous large mountain lakes lie interspersed among the peaks
at elevations of 2500 to 2900 feet. They are evidently shallow, and
are usually 300 to 500 yards in length. With the exception of the
" Lagoa Rosada," not one of them could be regarded as occupying
old crater cavities. They are : —

1. The " Lagoa das Teixas," behind San Roque.

2. The " Lagoa Paul," at the foot of Pico Topo.

3. The Lagoa Caiado," lying W.S.W. of Praynha do Norte.

4. The " Lagoa Rosada," in the Caldeira de Santa Barbara dis-

trict.

5. The " Lagoa do Ilheo," behind Santo Amaro.

6. The " Lagoa Negra," behind Santo Amaro.

The peaks are mostly bare of trees and shrubs, and on their steep
slopes sheep browse in numbers. The only one of them that I
ascended was Pico Topo, which lies behind Lagens, and proved to
have an altitude of only about 3300 feet instead of 5357 feet as stated
in the Admiralty chart. It is a long, ridge-shaped, hog-backed
mountain, which rises precipitously from the coast on the southern
and eastern sides, but is elevated only about 700 feet above the plains
on its north side.

Very moist conditions prevail in the elevated plains between the
mountains amongst which the lakes lie. In this upland region,
2500 to 2800 feet above the sea, there are extensive wet moors, where
Sphagnum, Polytrichuin, Carices, Anagallis tenella, Hydrocotyle
vulgaris, etc., thrive, as well as large areas covered with wood and
bush, where the Juniper is at home, and where filmy ferns (Hymeno-
phyllum and Trichomanes) abound. The humidity of this region
affords a great contrast to the relatively dry conditions prevailing
at similar altitudes on the slopes of the great cone of Pico. Even
in fine August weather the grass and herbage in the trails remained
wet during most of the day, and one's boots and leggings quickly
became soaked through even late in the morning. It is the land of
the Juniper and of the plants of the boggy moor ; and though drier
bracken moors are frequent, where, besides Pteris aquilina, there
grow Calluna vulgaris, Erythrcea massoni, the Azorean variety of
Lysimachia nemorum, Lycopodium selago, Polygala vulgaris, Potentilla
tormentilla, etc., it is to the two first-named features that the lake region
between the mountains owes its most conspicuous characters.

In the woods the Junipers attain a much larger size than on the
slopes of the great mountain of Pico, their height being often fifteen
or sixteen feet, and their diameter fifteen to eighteen or even twenty
inches. Here the Loranth, Arceuthobium oxycedri, flourishes in
places on the Junipers. The other components of the bush are the
Tree-Heath {Erica azorica), the Tree-Euphorbia {E. stygiana),

380 PLANTS, SEEDS, AND CURRENTS

Laurus canariensis, Myrsine africana, the common species of Smilax,
Vaccinium cylindraceum, etc., and among the ferns, Acrostichum
squamosum^ Dicksonia culcita, and Osmunda regalis, and we may
here add Lycopodium complanatum. The Vacciniums come next
to the Junipers in frequency, and grow so rankly that they may
reach a height of from twelve to fifteen feet, thus becoming arbores-
cent. At one time Taxus haccata flourished in this region, and its
name is still preserved in the name of the lake behind San Roque,

Lagoa das Teixas " ; but it is rare in that locality now, and seems
mainly to survive in the gulleys, about 2000 feet above the sea, on
the mountain slopes behind that village. I come now to the descrip-
tion of the lakes.

The Lagoa das Teixas (Lake of the Yews), located as just stated,
is a shallow lake, 350 to 400 yards in length, and half that in breadth.
It is elevated about 2500 feet above the sea. It is also known as
the Lagoa do Capitao Alexandre, after a former governor of the island
and o\^TLer of the property. The shallows are largely occupied by
Potamogeton polygonifoHus, which covers no small part of its surface.
A broad margin of Scirpus fluitans, so dense in growth that one can
walk upon it, skirts the water's edge. Outside this is a boggy belt
where thrive Sphagnum, Scirpus multicaulis, Carex flava, Hydrocotyle
vulgaris, Anagallis tenella, etc. Flourishing in places on the south
and west sides, and mainly covering the soppy marginal flats, is
the large form of Littorella lacustris, with long cylindrical leaves
measuring six to nine inches.

The Lagoa do Caiado lies, as the crow flies, about three miles
^y.S.W. from Praynha do Norte, in the district known as the Serra
da Praynha. Elevated about 2600 feet above the sea, it is about
500 yards long and 400 yards broad. Like the Lagoa das Teixas,
it occupies a shallow basin between the hills and cannot be very
deep. At its north-east end the banks holding back the waters
are so low that apparently it would not be very difficult to make
a cutting and drain its waters down the mountain sides. Sphagnum
thrives in the boggy margins, and here grow Carices, such as Carex
flava, Scirpus multicaulis, Anagallis tenella, Hydrocotyle vulgaris,
etc., whilst Peplis portula is common at its muddy edges. Littorella
lacustris and Isoetes azorica flourish at the borders, both displaying
two forms, the dwarfed form of the mud-flat and the large, long-
leaved form of the watery mud or of the deeper water. Some of
the deep-water plants of Isoetes, that w^ere washed up on the banks,
had leaves eighteen to twenty inches in length. (Further details
relating to the mode of occurrence of these two interesting plants
are given a few pages later.) Potamogeton polygonifoHus covers
extensive areas of the shallows of this lake. In one or two places,
where the bush gro'w'th of the surrounding district descends to its
borders, Osmunda regalis may be observed close to the water's
edge.

The Lagoa Paul, lying just under Pico Topo on its north-west
side, was dry when I visited it on July 30, 1914. When full of water
it would be smaller than the Caiado Lake. On the surface of the
exposed mud-flats, which were still moist, grew in quantity the

THE AZORES

381

dwarfed forms of the species of Isoetes and Litiorella above named ;
the latter formed almost a turf.

The Lagoa Rosada, or the Rosy Lake, is situated in the middle of
the island between Ribeiras and Praynha do Norte and near the
Caldeira de Santa Barbara, indicated in the chart. Elevated about
2950 feet above the sea, it occupies the bottom of a broad basin,
which may possibly be of crateral origin, and it is the only one of
the large mountain lakes that could be so regarded. It is oval in
shape, and is between 200 and 250 yards long, and from 100 to 150
yards broad. Viewed from the slopes above in the late afternoon,
its waters had a beautiful inky-blue hue, so that Lagoa Coerulea "
seemed a more appropriate name. Besides Potamogeton polygoni-
folius, the two forms of Isoetes azorica and Littorella lacustris here
thrived.

Lying close together in a level district on the top of the mountains
behind Santo Amaro, and elevated between 2800 and 2900 feet above
the sea, are the Lagoa do Ilheo (Lake of the Isles) and the Lagoa
Negra, or the Black Lake. The Lake of the Isles is about the size
of the Caiado Lake, if not larger. It contains two islands, and is
half-covered by the Potamogeton so common in these mountain
lakes; whilst a tall form of Scirpus palustris, two feet in height, is
not uncommon in the shallows. The Lagoa Negra is about 300
yards in length and oval in shape. Here were to be seen the species
of Potamogeton, Littorella, and Isoetes above named.

A number of small, circular, shallow lakelets, twenty-five to fifty
yards across, fill the bottom of the craters of the numerous small cones
dotted about this elevated lake region. Occasionally in midsummer
they are almost dried up, when the still moist muddy surface may be
covered by a turf of Scirpus fluitans, which doubtless resumes its
usual aquatic habit when the lakelet refills in the rainy season.
More often they are appropriated by the ubiquitous Potamogeton
polygonifolius, or, when the surface is clear, plants of Isoetes azorica
and Littorella lacustris in their two forms thrive in their waters and
at their borders. It may be here added that almost all the aquatic
and sub-aquatic plants previously mentioned in connection with
the island of Pico flourish in one or other of the numerous small
crater lakes of the island. Sphagnum often growing at their borders.

In the vegetation around the large lakes of this region one can
sometimes recognise a succession of formations. Whilst the Potamo-
geton before named occupies the shallows, Scirpus fluitans monopo-
lises the soppy ground at the lake's border, and outside this is a
broad belt of Sphagnum, where Scirpus multicaulis, Carex flava,
Anagallis tenella, and Hydrocotyle vulgaris thrive.

With regard to the occurrence of Littorella lacustris and Isoetes
azorica in this region of the mountain lakes, some further remarks
may here be made. Both display two forms, a dwarfed form on
the exposed mud-flats, and a large form with long cylindrical leaves
growing in the deeper water, as in the case of Isoetes, or where the
water just covers the ooze at the lake's margin, as with Littorella.
Whilst the dwarfed plants of Littorella lacustris were well in flower
at the end of July, the large plants were only showing the flower-

382 PLANTS, SEEDS, AND CURRENTS

buds ; the latter possess cylindrical leaves, six to nine inches long, which
lie prostrate in the water, and are not erect, as has been sometimes
described. It was evident that the floating growths of Potamogeton
polygonifolius were inimical to the growth of the large forms of
Littorella and Isoetes. They are rapidly extending in the ponds, and
not improbably will ultimately exterminate the last-named plant.

The Uplands of the Island of San Miguel. — The great upward
extension of the cultivated zone, and the large intermingling of
foreign trees and shrubs with the indigenous trees and shrubs of
the lower slopes up to 2000 feet, will cause our interest to be mainly
centred on the upland regions as best illustrated in the mountainous
eastern portion of this island. It may, however, be observed that
on the lower slopes of San Miguel, as far as they are still held by the
indigenous flora, occur the characteristic trees and shrubs of the
lower woods of Pico, such as Erica azorica, Laurus canariensis,
Myrica faya, Myrsine africana. Viburnum tinus, etc., the last named
being more generally distributed over the island than it is on Pico.

Without further remark I will proceed with my notes on the
ascents of the Pico da Vara Range in the eastern part of San Miguel,
a range that culminates at an altitude of 3570 feet in the peak of
that name, the highest point of the island. My ascents were made
in the latter part of February ; but it is evident from Drouet's account
of the vegetation of the higher slopes of the range in May, that
except for the plants in bloom my notes will give a fair idea of the
general characters of the larger vegetation in that weather-beaten
region.

Pico da Vara, the highest peak of the range, rises abruptly about
600 feet at the eastern extremity of a long, flat-topped, wind-swept
ridge that forms the mountainous backbone of the eastern part of
San Miguel, and attains a general level of about 3000 feet above
the sea. It is a cloud-begirt, wind-buffeted region of heavy rainfall,
and it receives the full force of the Atlantic gales. One may walk
for three miles along the flat crest of this ridge from its western
end without changing one's level more than 200 feet. The soil
there is derived from the prevailing coarse, andesitic, pumiceous
tuffs; but the materials are only partially disintegrated, so that
one crunches underfoot the loose, sodden, pumice gravel that strews
the surface. On the crest of this mountainous backbone occur
stunted growths of Juniperus oxycedrus and Laurus canariensis
(Laurel), mingled with Myrsine africana, Vaccinium cylindraceum,
and the Culcita fern (Dicks onia culcita) ; and in response to the
prevailing moist conditions there are tussocky growths of Polytrichum.
At the western end of the range, where the ridge broadens out into
a kind of table-land, the surface is in places boggy, and in the pools
grow Potamogeton polygonifolius and Callitriche aquatica, with
Sphagnum and J uncus at the borders.

But the stunted growths of the Juniper and the Laurel largely
monopolise the higher slopes of this mountain ridge, the Laurel
reaching to the top of the ridge and the Juniper extending to the
summit of the eastern peak. In this wind-swept region their height
is usually between two and three feet; but where the exposure is

THE AZORES

383

greatest the Juniper grows semi-prostrate on the ground. Besides
the Juniper, Dicksonia culcita also reaches the very top of the island,
being accompanied by dwarfed growths of Myrsine africana and
V accinium cylindraceum.

Yet this is but a winter view of the vegetation of the higher levels
of the Pico da Vara Range. In summer, when picnicking parties
from the Furnas Valley ascend these mountains, herbaceous plants
in abundant bloom adorn the slopes; and, if the weather is fine,
there would be little in these breezy heights, with a magnificent
panorama at one's feet and a clear sky overhead, to suggest that
any risks would attend an ascent in winter. But the little stone
crosses on the top of the ridge tell another story. Shepherds, over-
taken by the blizzard in mid- winter, have lain down and died ; and
under conditions that were certainly elemental the writer had an
experience on these storm-swept levels of the influences that have
oppressed the Junipers and Laurels through the ages. He was
overtaken by a succession of squalls from the north-west. For
nearly an hour, enveloped in the clouds and without any shelter,
he was exposed to a pitiless storm of wind and rain. Subsequently,
on reaching the summit of the peak, he found Sibthorpia europcea in
foliage in the shelter of a small pit, the sides of which were lined by
Liverworts (Hepaticce) ; but with the exception of the narrow-leaved
variety of Thymus serpyllum, in leaf only, there was little else in
the lesser vegetation of these heights to remind one of the summer
dress of the slopes of Pico da Vara.

Judging from Drouet's reference to his ascent of this range, the
general extent of the larger vegetation at the top was much the same
in 1857 as it was in 1913. But the tale of the pumice-strewn soil
of the upper slopes is fairly clear. The interval that has elapsed
since the great eruption of the Furnas Valley in 1630, when, according
to Walker, all the vegetation in the eastern part of the island was
overwhelmed by ashes and covered to a depth of many feet, has not
been long enough for the restoration of the original forests on these
mountain slopes. The struggle of the plants to regain their own
has been rendered still more difficult by the repressive influence of
the winds on these stormy heights.

Ascent of Santa Barbara, the highest Mountain of Terceira,
3500 Feet above the Sea. — My ascent was made from Angra in
the middle of April. Although the zone of cultivation extends up
to about a thousand feet, that does not represent the limits of man's
destruction of the original forests, since on the higher slopes, where
doubtless these forests once grew, scrub is »now only to be found.
The scrub is formed chiefly of Juniper and Calluna vulgaris (Ling),
with Myrsine africana in places. The Ling occupies the lower
slopes below 2200 feet where the ground is dry and the soil poor and
stony, and it is accompanied by Thymus serpyllum in its dense-
growing, trailing, narrow-leaved Azorean form. The Juniper
predominates on the higher slopes, where the ground is wet and often
t)Oggyj a^nd where Sphagnum and Polytrichum thrive. The higher
parts of this mountain are much wind-swept and often cloud-invested,
and on account of the clouds, rain, and wind I was unable to make

384 PLANTS, SEEDS, AND CURRENTS

a long stay on the summit. But the ascent is by no means an inter-
esting experience for the botanist, since his thoughts are more Ukely
to dwell on the lost forests than on the surviving vegetation.

The Characteristic Coast Plants of the Azores. — Though
my experience was mainly confined to the island of Pico, it can be
supplemented by notes made on Fayal and San Miguel. The coasts
of the islands of the Azores are mostly rock-bound and often pre-
cipitous, beaches of any size being, as a rule, infrequent. The most
typical plants include the following, which are more or less generally
distributed over the group — Beta maritima : Crithmum maritimum ;
Euphorbia azorica, regarded by some as a variety of the South Euro-
pean E. pi?iea, L. ; Euphorbia peplis ; Hyoscyamus alhus ; Juncus
acutus ; Plantago coronopus ; Polygonuju maritimum ; Salsola kali ;
Silene maritima ; Spergularia marina, probably far more ^Wdely
distributed in the group than is admitted by later authors ; and
Statice limonium.

One of the most interesting localities for beach plants that I came
upon was the sandy beach of Porto Pym, in Fayal. In their order
of frequency the plants were Ipomcea carnosa, R. Br., Salsola kali,
Euphorbia peplis, Cakile edentula, and Polygonum maritimum. Some
of them, such as the species of Ipomcea and Cakile, are kno\^Ti to have
been gro^^ing on this beach for more than seventy years, having
been found there by Watson in 1842, and collected since by other
botanists, as by C. S. Bro^^Ti in 1894. It is probable that Cakile
edentula was originally introduced vriih. ballast, a matter discussed
in the general treatment of that plant.

The most frequent plant on the rocky coasts of Pico is Euphorbia
azorica ; hut Plantago coronopus and Juncus acutus are also common.
On the sandy beaches grow in places Polygonum maritimum, often
in association %^-ith Hyoscyamus alhus ; whilst Salsola kali occurs
scantily. Silene maritima and Spergularia marina grow both on
the sand and on the rocks, and sometimes in sandy pockets in the
lava rock. Crithmum maritimum (Samphire) is found here and there
on the rocks, as at Praynha do Norte ; but it is much appreciated
by the inhabitants for eating with fish, and it is likely that its relative
scarcity on the Pico coasts is due to this cause. On the beach just
south of Magdalena I found Ipomcea carnosa, previously only kno\sTi
in this group from the island of Fayal.

On the rocky coast at San Mattheus and at Magdalena there
exists a peculiar plant, concerning the identity of which I am in
doubt. It is a very fleshy plant, of which uimamed specimens
from San Jorge in the herbarium of the Ponta Delgada Museum
are enclosed in a Mesembryanthemum cover, having been collected in
1905 and 1908, or ten or twelve years after Trelease's visit. The
plants grow prostrate on the lava rocks, and have purplish terminal
flowers. They exist in quantity on the rocky flat close to a windmill
just north of the iovra of Magdalena. The species comes nearest
to Mesembryanthemum ; but it has a four-valved capsule that dehisces
loculicidally, leaving the axis in the centre of the fruit. The seeds
have the appearance of Stellaria seeds, and are round, blackish,
scrobiculate or warty, about a millimetre across, and have an embry o

THE AZORES

385

curved around a mealy albumen. In another cover in the herbarium
were specimens of quite another plant, labelled Tetragonia expansa,
from the Azores, the island not being named. I find no reference
to any of these plants in the pages of either Watson or Trelease.

Another Azorean shore plant is Solidago sempervirens, an American
littoral species, which, as we learn from Seubert, extends inland to
a height of 1000 feet above the sea. Campanula vidalii, which is
peculiar to the Azores and occurs principally on the sea-cliffs and
coast rocks of Flores, is specially discussed in the notes on Azorean
plants at the end of Chapter XIX.

Summary

1. During his two sojourns in this group the writer was principally"
engaged in investigating the altitudinal ranges of the indigenous
plants; and with this object the vegetation of the great cone of
Pico, by far the loftiest mountain in the archipelago, was especially
studied. His ascents, and the best methods to be followed in examin-
ing the higher slopes of the mountain, are first described (pp. 359-61).

2. A sketch of the history of the botanical investigation of the
Azores is next given. This exploration, which commenced with a
small collection of dried plants made on Fayal in 1775 by George
Forster, one of Cook's naturalists, and with collections of living
plants made for Kew Gardens by Masson a year or two later, has
since been carried out by a number of botanists and naturalists of
various nationalities — American, English, French, German, Portuguese,
and Swiss. We may mention here Guthnick and the Hochstetters
in 1838; Watson in 1842; Carew Hunt during 1844-8; Drouet
(zoologist), Morelet (zoologist), and Hartung (geologist), all in 1857;.
Godman (zoologist) in 1865; Brown in 1894; Trelease in 1894 and
1896 ; and last, but by no means least, resident Portuguese botanists^
such as Carreiro, Machado, and Sampaio. The works that form
landmarks in the investigation of the flora are those of Seubert
(1844), Drouet (1866), Watson (1870), and Trelease (1897) (pp. 361-4).

3. Before dealing specially with the vegetation of Pico, allusion
is made to the heights of the islands of the Azores (p. 364). This leads
one to compare the conditions for forest growth in this group with
those in the Canaries and in Madeira, a comparison that supplies
an opportunity of forecasting the correlation of the three floras,
and leads us to look for in the Azores only the evergreen shrubs and
trees of the Canarian Laurel woods (p. 365).

4. The general profile of the great mountain of Pico is then described
(p. 366) ; and in this connection the bluffs of the Ribiera Grande
are mentioned as presenting one of its principal spectacular features
(p. 366).

5. After disposing of the not uncommon error that the higher
slopes of the cone are barren, the author deals with the extent of
the vegetation on the mountain. The lower slopes are generally
well vegetated up to 4500 or 5000 feet, moor and grass land pre-
dominating in their higher levels between 2000 and 4000 feet. But
woods are well developed in places, the lower woods on the western

c c

S86 PLANTS, SEEDS, AND CURRENTS

•side and the upper woods on the south-eastern side. They are
essentially formed of evergreen shrubs and trees; but on account
of the persistent agency of the woodcutter through centuries the
trees, except when specially preserved, rarely exceed twenty feet
in height, and are usually not more than fifteen or sixteen feet.
Dwarfing begins, as a rule, at about 4000 feet, as the effect of deficient
soil and of exposure to strong \vinds. Above 5000 feet are the
sparsely-vegetated, precipitous lava slopes of the cone proper;
'but in spite of the conditions five or six kinds of plants, usually as
stunted and creeping growths, reach the summit (p. 367).

6. The writer then comes to his special study, the zones of vegeta-
tion on the great mountain of Pico. This subject is not dealt with in
the later works on the flora, which are almost exclusively devoted
to the systematic treatment of the plants, and were the only sources
of information accessible to him at the time of his visits. The
result was that after he had completed his study he found that in
the main he had long before been anticipated by the earlier German
and French investigators, particularly by the Hochstetters (p. 368).
The zones of vegetation adopted by the writer for this mountain do
not differ very materially from those of his predecessors. They are
as follows : —

I. The Lower Woods, or the Faya zone, Myrica faya being one
of the most characteristic of the trees. The zone extends usually
from the coast up to 2000 feet. Besides the Faya, the other trees
peculiar to the zone are Rhamnus latifolius, Persea (Laurus) indicaj
and Picconia excelsa. Among the trees that are abundant in both
the Upper Woods and the Lower Woods are Ilex perado, Erica azorica,
and Laurus canariensis. Of the shrubs the Laurestinus {Viburnum
tinus) is restricted to the zone ; whilst Vaccinium cyliiidraceum and
Myrsine africana, abundant here, are equally common in the Upper
Woods.

II. The Upper Woods, or the Juniper zone. Juniperus oxycedrus
(var. brevifolia). Daphne laureola, and Euphorbia stygiana are the
most distinctive of the trees and shrubs ; whilst Erica azorica. Ilex
perado, Laurus canariensis, Myrsine africana, and Vaccinium
cylindraceum are as characteristic of this as they are of the zone
below. Taxus baccata, now almost extinct, thrived originally in
the lower levels of the Upper Woods and in the higher levels of the
Lower Woods. The Loranth, Arceuthobium oxycedri, is a frequent
parasite on the Juniper trees. This zone extends usually from 2000
to 4500 feet, but is continued as a scrub up to 5500 feet.

III. The highest zone of the cone proper, 5500 to 7600 feet. All
•the plants growing on these scantily vegetated, steep, lava slopes
"have climbed up from the lower levels, principally from the moors,
as described below. They include Calluna vulgaris, Menziesia
polifolia, Thymus serpyllum (var. angustifolius), Polygala vulgaris,
and Agrostis castellana, all of which reach the summit.

IV. The zone of the Upland Moors, 2000 to 4000 feet, which has
l)een formed at the expense of the Upper Woods around much of
the mountains. Here we find many of the features of a Devonshire
moor, as on Dartmoor. The most striking general features are the

THE AZORES

387

Bracken (Pteris aquilina), the large tussocks of Polytrichum^ and the
beds of Sphagnum. Among the most frequent flowering plants
are Anagallis tenella, Calluna vulgaris, Carex flava, Erythrcea massoni,
Hydrocotyle vulgaris, Luzula purpurea- splendens, Lysimachia nemorum
(var. azorica), Menziesia poUfolia, Poly gala vulgaris, Potentilla
torrneniilla, Sihthorpia europcea. Thymus serpyllum (var. angustifolius),
and Viola palustris. In and around the pools grow Callitriche
aquatica, Carex stellulata, Littorella lacustris, Peplis portula, Pota-
mogeton polygonifolius, Scirpus fluitans, S. multicaulis, etc. (pp. 368-71).

7. After discussing the prevailing climatic conditions on the upper
slopes of the great mountain (p. 371), the writer gives a general
account of its vegetation, commencing at the summit; but only
some of the special features can be here alluded to. Thus it is noted
(p. 373) that occasional stragglers from the upper woods reach far
up the mountain, stunted specimens of Ilex perado having been
observed at 6300 feet. Then it is remarked that on the scantily-
vegetated lava slopes, between 5000 and 6000 feet, a number of
herbaceous plants find a sanctuary in the beds of Ling {Calluna vulga-
ris), and that even the Juniper, as dwarfed specimens only six inches
high, finds protection there (p. 373). The prevalence of filmy ferns '
such as Hymenophyllum tunhridgense, on the tree-trunks of the upper
woods indicates the humidity of the conditions in that zone, the
limits of which roughly correspond to those of the rainy belt (p. 375).
Two plants range through the whole height of the mountain, namely,
Calluna vulgaris and the narrow-leaved variety of Thymus serpyllum
(p. 376). Special reference is made to the unusual development
of Sphagnum on the south-west side (p. 377).

8. The manner in which small craters and gulleys on the higher
slopes serve as refuges for plants of the lower slopes is then treated.
In this way plants of the lower woods find a home in the upper
woods, and plants of the upper woods in the slopes above (pp. 374-5).

9. The mountain-lake district of the island of Pico is next de-
scribed. Here several lakes occur at altitudes of 2500 to 3000 feet
in the midst of a region of extensive wet moors and of large areas
covered with wood and bush. Very moist conditions prevail in
the woods, and here the Junipers attain their largest size, the compo-
nent trees being those of the upper woods of the great cone. Yews
(Taxus baccata) were once frequent in this locality, but are now
rare. The lakes are described in detail ; and in the account of the
vegetation growing in and around them the frequent association of
Littorella lacustris with a species of Isoetes is noticed (pp. 379-82).

10. Some remarks are then made on the vegetation of the island
of San Miguel. On the lower slopes, so far as they are still held by
the indigenous flora, occur the characteristic trees and shrubs of
the lower woods of the mountain of Pico. The writer describes
his ascent in winter of Pico da Vara, the summit of the island, and
he observes that stunted growths of Juniper and Laurel (Laurus
canariensis) largely monopolise the higher levels of this mountain
ridge (pp. 382-3). A short account is given of his ascent of Santa
Barbara, the highest summit of Terceira, an ascent that is deprived
of much of its interest through the destruction of the forests (p. 383).

388 PLANTS, SEEDS, AND CURRENTS

11. Then follows a short discussion of the seashore plants of the
Azores, of which the most characteristic seem to be — Crithmum
maritimum, Euphorbia azorica (perhaps a form of E. pinea of South
Europe), Euphorbia peplis, Hyoscyamus albus, Juncus acutus.
Polygonum maritimum, Salsola kali, Silene maritima, and Spergularia
marina (p. 384).^

12. Under the head of " The Wells of Pico," in Note 36 of the
Appendix, the extensive soakage seaward of underground waters is
noticed; and evidence is adduced to show that this is a common
phenomenon in large islands, and that sometimes fresh-water thus
derived issues as submarine springs off the coast. On the great
cone of Pico there are no permanent streams and no springs, the
poorer inhabitants of the coast towns and villages mainly depending
on the slightly brackish water of wells sunk in the rubble behind
the beaches. Off the cone, in the eastern part of the island, perennial
springs occasionally exist high up the slopes of the mountains.

^ Frankenia pulverulenta is also an Azorean shore plant which, however,
rarely came under my notice.

CHAPTER XVIII

THE AZORES {continued)

The Proportion of Native or Indigenous Plants in the
Azores. — In these pages we are concerned only with the native
flora, and it may at once be remarked that it was in all probability
extremely limited. The matter of the introduced plants cannot
therefore be dealt with here in any detail; but, from what follows,
it will be evident that in restricting the field of discussion to the
native plants, we assume a very great reduction in the size of the
present flora, a flora which has often been erroneously described
in general references to the archipelago as in the mass indigenous.
The very opposite is, indeed, the case; and if we wish to obtain
a sense of proportion in this respect we cannot do better than go
back to the writings of the earlier botanists interested in the flora,
those who, like Seubert and Hochstetter, employed only the truly
indigenous plants to characterise their zones of vegetation above
the region of cultivation.

The islands have been colonised for more than four centuries,
and during that period multitudes of species have been introduced,
either by accident or by intention. Without discrimination, it
would be possible to make an extensive collection at the present
time that would include hardly any of the native flowering plants,
and the same could have been done a century or two ago. In fact,
a small collection of about twenty-seven species, gathered by George
Forster on Fayal in 1775, was almost entirely composed of plants
that had been introduced since the discovery of the islands (see
Note 33 of the Appendix). Trelease, the most authoritative of
recent investigators of the flora from the standpoint of the systematist,
finds no difficulty in seeing how " most of the existing species may
have been introduced by ordinary means, largely through human
agency, since the discovery of the islands " (p. 67) ; and one cannot
be many weeks in the group without recognising the correctness of
this opinion. Watson's total of 439 flowering plants is increased
in Trelease's pages to about 560; but I should imagine that the
original flora did not comprise 200 species, and that the plants which •
gave their impress to the vegetation did not amount to a hundred.

Watson makes but little effort, as he himself admits, to distinguish
the introduced plants in his catalogue. His position with regard
to alien plants is not easy to appreciate now. The old Forbesian
hypothesis of a great continental extension of Europe westward
would, if applied to the Azores, scarcely raise the question of intro-
duced plants. Watson was aware of this, and although taking a

389

390 PLANTS, SEEDS AND CURRENTS

neutral attitude in the matter he adopted the implication as regards
alien plants. He considered that all " recorded constituents " of
the Azorean flora should be taken into our " statistical reckonings "
(p. 264), and he made a numerical analysis (p. 272) without any
further differentiation than one based on geographical considerations.
The results were used by Godman, with no comment on the pre-
dominant proportion of alien plants, in his concluding general remarks
on the natural history of the islands (pp. 332, 334), and, as is noted
below, by other writers on insular floras.

The effect has been unfortunate, since these writers have treated
Watson's catalogue of 439 plants as a list of native plants. He him-
self remarks (p. 262) that his catalogue includes many species that
have been introduced into the Azores; but evidently it did not fall
within the scope of his work, as he viewed it, to discriminate to any
extent between the natives and the aliens among the plants. To
take one instance, Watson's list includes about two dozen species
in all of Medicago, Trifolium, and Lotus, of which the majority must
have been introduced since the discovery of the islands; yet there
is nothing to indicate it. Then again, of the fifty-one grasses named
he only particularises three as possibly introduced. So also of the
six species of Geranium and Erodium, almost all of them common
ruderal species, of the sixteen species of Labiatce, which include many
roadside and waste plants spread by cultivation, and of such familiar
world-ranging weeds as Oxalis corniculata, Plantago major, P. lanceo-
lata, Rumex crispus, etc., nothing is said of their alien origin.

The outcome of this will now be shown. When Godman in his
book on the group (p. 342) compared the proportion of peculiar
Azorean plants with those for birds, insects, and land-molluscs,
he was employing Watson's entire list of plants as though all were
natives of the islands. Then again there was little in Watson's
work to guide Wallace in discriminating between native and foreign
flowering plants, when he made an analysis in his Island Life of the
439 Azorean species based on their capacity for dispersal. Yet
he was fully sensible of the difficulty involved. There can be "
(he writes, edit. 1892, p. 260) " little doubt that the truly indigenous
flora of the islands is far more scanty than the number of plants
recorded would imply, because a large but unknown proportion of
the species are certainly importations, voluntarily or involuntarily,
by man. ... It is almost impossible now to separate them, and Mr.
Watson has not attempted to do so." He goes on to say that even
if only half of the species are truly indigenous there would remain
a wonderfully rich and varied flora to have been carried by the
various means of dispersal. But apart from this, the danger of
treating all the plants in Watson's list as native plants has not always
been avoided. Thus, in comparing the endemic element in insular
floras, Watson's total for the Azores has been sometimes utilised as
if it were composed entirely of native plants. This is the case in
a list given in the Introduction to the Botany of the Challenger Expedition
(p. 33). Then again in works of reference the same thing is done.
Thus in the article on the Azores in the 9th edition of the Encyclo-
pcedia Britannica, which was written before 1875, all the 478 flowering
plants, ferns, and lycopods, etc., of Watson's list are characterised

THE AZORES

391

as " generally considered as indigenous." Yet Watson's attitude
reflected the prevailing opinion among botanists in this matter.
Hooker, in his famous lecture on Insular Floras in 1866, a lecture
which has formed the foundation of all later studies of these floras,
would almost seem to imply that the 350 species of flowering plants
then known were all natives.

It is not easy for us now to grasp the pre-Darwinian conception,
current in the middle of last century. It was the period of change
between two eras, and it was left to Trelease in recent years to
recognise the limited character of the true native flora of this group*
The flowering plants designated by him as introduced since the
occupation of the islands, including weeds, escapes, casuals, etc.,,
number in all nearly 200; but even Trelease omits to mark as alien
to the native flora a considerable number of species, such as Lamium
purpureum, Stachys arvensis, Oxalis corniculata, Geranium molle,
G. rohertianum, G. dissectum, Galium aparine, etc., amounting pro-
bably to almost another hundred, which must be regarded as having
been introduced since the discovery of the archipelago.

One way of testing this matter, as suggested to me by Mr. Hemsley,
is to take the case of the New Zealand flora, where the introduced
plants have been carefully discriminated by Cheeseman. This,
however, would probably develop into a much larger undertaking
than I could begin now, since numbers of collateral questions would
arise, and the area of comparison would certainly require to be greatly
extended as the inquiry proceeded. Unless some abler worker takes
up the subject, I hope to begin the task some day. It would be
important to eliminate the agency of man, direct and indirect,
from every flora, and to apply the same method to all. Such an
inquiry might be almost as ruthless in its effects on the British flora,
as it would undoubtedly be in the case of that of the Azores. As
applied to the group just named, the term " native flora " denotes
the plants in the islands before their occupation by man. It has
in practice a widely different meaning in the case of the British
Isles, and includes a host of ruderal plants. Yet if a weed had been
present here for half a million years, it would still be a weed and never
a part of the native flora.

Whatever the antiquity of the weed, its differentiation from the
native plants of a flora, or, in other words, the disentanglement of man's
influence in the history of the plant- world, becomes the first requisite
for the proper study of distribution. Whether a region was first
occupied by man 400 or 400,000 years ago matters little. The weed
of to-day is the weed of prehistoric ages, and its story is bound up
with the story of man on this globe. Results, both unexpected and
important, would be the outcome of such an investigation.

Probable Composition and General Characters of the.
Original Forests of the Azores. — Although he did not see his
way to assist us in the differentiation of the weeds, Watson (p. 268)
gives some valuable suggestions that enable us to form a mental
picture of most of the general characters of the dense woods that
covered these islands at the time of their discovery. We may here
emphasise his opinion that evergreen shrubs and trees, with ferns
and mosses, formed the principal feature of the vegetation, and that

392 PLANTS, SEEDS, AND CURRENTS

" a close forest of evergreens must have formerly covered the ground."
After a few weeks in the islands the present writer found himself
unconsciously restoring the evergreen woods that once predominated
in the group. All the trees and shrubs indicated by Watson as
composing the original forests are named below, with one exception,
Myrtus communis, the indigenous character of which has not always
been admitted. Four others have been added in my account,
namely, the species of Taxus, Euphorbia, Smilax, and Rhamnus, of
which the first has been recognised by Trelease and others as originally
native, whilst the other three are peculiar Macaronesian species
(Macaronesia comprising the Azores, Madeira, and the Canaries)
that are held by Watson as well as by Trelease as truly indigenous
Azorean plants. All were evergreens, even Prunus lusitanica.

Amongst the trees, Erica azorica, Laurus canariensis, Myrica faya,
and Juniperus oxycedrus (var. brevifolia), would have been most
frequent. Ilex per ado would have been well represented, together
with Picconia excelsa and Taxus baccata. Rhamnus latifolius, a
sub-evergreen, doubtless took its share, together with Prunus
lusitanica, the latter being now only known from San Miguel. The
Tree-Euphorbia (E. stygiana) was probably more frequent than it
is at present. Among the evergreen shrubs, Myrsine africana, it
is likely, took a leading part ; Vaccinium cylindraceum was abundant ;
and whilst Daphne laureola flourished in the upper woods, Hypericum
Joliosum was common in the lower woods. The Laurestinus shrub
{Viburnum tinus) was well represented in places; and climbers like
Smilax canariensis and Hedera canariensis were conspicuous. One
cannot, however, pursue this subject here, and reference will now be
made to another feature of the original evergreen forest, of which
mention has not yet been made.

The Large Size of the Trees in the Original Forests. — One
can scarcely be surprised that authors, judging the past from the
present, should write depreciatingly of the original forests of the
Azores. Godman (p. 4) characterises them as " underwood " ; and
Watson (p. 268), when alluding to their features, speaks of the
*' frutescent and sub-arborescent " species, and of the " shrubs and
small trees," of which they were composed. Hartung, who spent
four months as a geologist in these islands in 1857, takes the same
view in his book; but he depended mainly on Watson and Seubert
for his botanical information, and made but few original observations
except in the case of the buried Junipers. He was anxious to labour
the point that the plants which are trees in the Canaries and Madeira
become shrubs in the Azores; and he even rejected the adverse
testimony of his buried Juniper trees, a subject discussed in a later
page. A juster appreciation is given in Seubert's work, which is
based on the observations of the Hochstetters, where it is stated
that plants such as Erica azorica, Laurus canariensis, and Myrica
faya, which form bushes in the higher zones, grow as true trees in
the lower woods.

Deforestation at the hands of the woodcutters has been in progress
for centuries, and in no localities more than in the woods bordering
the roads or tracks, where only young trees grow. Visitors following
the ordinary routes would thus only see young wood ; and the trees

THE AZORES

393

growing in the woods farther back, often rendered difficult of access
by a dense growth of brambles, would not come under their observation.
This matter is discussed later ; and it will be sufficient to point out
here that in an ordinary traverse of the woods the trees would not
be seen at their best. This is illustrated in Watson's conception
of Myrica faya as a dense bush (p. 224); whereas, when allowed
to grow undisturbed it becomes a tree of respectable size, thirty-five
to forty feet high.

Yet it is abundantly evident from the old Portuguese and other
authorities of the sixteenth century quoted by Walker, such as
Fructuoso, Cordeiro, and Linschoten, that the islands were once
heavily timbered. In the middle of that century, according to
Fructuoso, there were dense and lofty woods of Cedars (Juniperus),
Fayas {Myrica faya), and Laurels (Laurus canariensis) on the slopes
of the valley of the Furnas in San Miguel. Linschoten was resident
in the group in the latter part of the sixteenth century. I have
consulted his account as given by Purchas (edition of 1905). Writing
of Tereeira, he says that " the island hath great store and excellent
kinds of wood, especially Cedar (Juniper) trees, which grow there in
so great numbers that they make Scutes, Carts, and other grosse
workes thereof." Of Pico he writes that it had " great store of wood,
as Cedars and all other kinds, and also the costly wood Teixo (Taxus
haccata). There they build many Carvels and small Ships; and
from thence, by reason of the abundance of wood, they serve the
other Islands with wood." It cannot, therefore, be doubted that
Pico, as Walker observes (p. 84), was " at one time densely covered
with timber of large size."

In the early history of the Azores the timber of the Juniper trees,
the " cedro " of the islanders, was extensively employed in building
the churches. Walker (p. 252) quotes an early Portuguese authority
to the effect that Tereeira, when first discovered, was densely wooded
with heavy timber, all the old churches and other buildings being
roofed with " cedar " wood. Tradition has it that the immense
beams even now in the roof of the cathedral at Angra were cut from
trees that flourished as late as 1570. According to the same authority,
the " last authentic record " of these " magnificent " Azorean Cedars
being still in a flourishing condition relates to their use to repair
a church at Villa Franca, in San Miguel, which was much damaged
by the earthquake of 1630. In the church at Magdalena, on the
island of Pico, which is said to have been built in 1710, a good deal
of Cedar has been employed in the chancel, but it is now often gilded
over. I learned from the priest that according to popular belief
the wood came from Pico. It would seem from Walker's pages
that most of the old timber trees in the group had disappeared before
the close of the seventeenth century.

Large Trunks of Trees buried in the Ashes of Ancient
Volcanic Eruptions. — The trunks of trees overwhelmed in the
early volcanic eruptions give similar testimony of the large size of
the trees of the original forests. Frequent reference has been made
by wTiters to their occurrence in the island of San Miguel. " From
the boles occasionally unearthed at the Seven Cities and Furnas "
(thus writes Walker, p. 25) " there is little doubt that these splendid

394 PLANTS, SEEDS, AND CURRENTS

trees, on its first discovery, inhabited a high belt of country extending
east and west along the island." But very large trunks of other
existing species of trees are also found buried in the volcanic tuffs
of this island. Thus Walker (pp. 219, 220) refers to trunks of the
Tree-Heath (Erica azorica) and of the Faya {Myrica faya) of giant
proportions, which have been exposed in a state of lignite (?) in the
ravines of San Miguel. So again, Carew Hunt, for years British
Consul in the Azores and the principal source of Watson's later
collections, when %mting of San Miguel in the Journal of the Royal
Geographical Society for 1845, states that there had been found in
the tuffs trunks of the Faya, Juniper, and Tree-Heath, the Juniper
with stems three feet in diameter.

Most of the data concerning these buried trees relate to the Juniper
or " cedar." "V^lien at Furnas in 1857, Drouet was shown an enor-
mous semi-carbonised ( ?) trunk of Juniper oxycedrus, which mdicated
that formerly the trees attained a far greater size than they do to-day.
It may here be said that this statement about the carbonisation
of the wood is probably incorrect. In a letter to me Colonel Chaves
emphatically denies the assertion of Walker, as above quoted, that
buried trees in a state of lignite have been unearthed in San Miguel.
The most important observations on these buried trees are, as he
points out, those of Hartung, who says nothing about such a condition
of the wood. It may be here apposite to give the results obtained
by the German geologist as stated in his Die Azoren, Leipzig, 1860.
He describes large trunks of the Juniper, that still grows on the
island, as buried beneath great thicknesses of volcanic materials
(blocks of tuff, pumice, and lava) heaped up during the later eruptions
in the regions of Sete Cidades and the Furnas Valley in San Miguel
(pp. 168, 200). In the Furnas Valley the thickness of the overlying
material is stated to be about 400 feet, the date of the last eruption
in that locality being 1660. The buried trunks of Juniper of the Sete
Cidades are characterised as " machtige Baumstamme " ; and the
diameters of two of them are given as two and an eighth and one
and a half feet. In this connection Colonel Chaves \ATites to me
saying that the biggest trunk of " cedar " (Juniper) found in the
Azores is the trunk still remaining in the Grotta do Inferno at Sete
Cidades. When referring to the Azorean Juniper, Trelease (p. 169)
remarks that " large logs, apparently of this species, occur deeply
buried under secondary volcanic debris in the Grotta do Inferno
of the great crater kno^Mi as Sete Cidades."

I am indebted to Miss S. Bro^^*n, of " Brown's Hotel," Ponta
Delgada, for some particulars relating to the buried " cedars " of
Furnas, where she long resided -^ith her father and brother. These
buried trees were not uncommonly to be seen in the Furnas Valley ;
but her father would never believe that trees of the large size indi-
cated by the logs existed there, until he found the stump of one of
these buried " cedars " sho\\-ing the bases of the roots. It was
found at a place called Alegria, at the north-eastern end of the
valley. In a little sketch kindly supplied to me by his son, who
was present at the time, this tree-stump is described as forty to
forty-six inches high, \\^th. a diameter of twenty-four inches at its
upper end, which apparently (as far as the sketch indicates) projected

THE AZORES

395

originally about two feet above the ground. Miss Brown was good
enough to send me a picture frame, made from one of these " cedar "
logs, which her father had purchased. I sent it to the Kew Museum,
and received through the kindness of Sir D. Prain the following
report by Mr. Boodle, who examined the wood with care : " The
wood appears to be that of a species of Juniperus, perhaps the same
species as the block of wood in the Kew Museum, also dug up in
the Azores. According to a label on this block. Masters states that
Senor Henriques showed that this wood is identical with that of
Juniperus hrevifolia^ In his letter to the author Sir D. Prain
says : " I am prepared to accept his verdict as at any rate definite
proof that the wood cannot be identified with anything but that of
a Juniper."

These buried Juniper trees have been also found in other islands
of the group. When at Horta I was told by Mr. Keating that up
to recent times the trunks were often dug up on Flores, and were
used for building the small sailing craft trading between the islands.
Writing of Terceira, Walker (p. 253) states that in various parts of
the island " are occasionally found immense cedar trees embedded
in deep ravines and valleys, still in perfect preservation." An
unearthed log sometimes proved to be a godsend to the islanders,
who promptly cut it up for firewood.

The whole subject of these buried trees of the Azores requires
systematic investigation; but there can be little doubt that the
group possessed an abundance of excellent native timber in the
early centuries of its occupation, and that it has none now. We
would be unable in our days to find any native trees large enough
to supply timber for the beams of the roofs of churches. Men,
goats, and cattle have been active agents in deforesting these islands
for four hundred years and more. Except when specially preserved,
it would be difficult to find on Pico trees more than twenty feet
high and more than thirty years old at the present day; and
the same remark would apply to the native trees of the other islands.

The Greatest Size attained by Existing Trees on the
Azores. — Facts of the kind just given led me to inquire into the
maximum size that the existing trees can acquire when unhindered
in their growth ; and it will be seen from the data to be now given
that they can attain quite respectable dimensions, although falling
far short of those indicated for the trees of the original forests. I
took up the matter on the island of Pico. Land is there valued for
the wood upon it, and it is profitable for the owner to leave his land
undisturbed for many years. The great demand for wood for firing
and other purposes usually prevents this being done; but in two
of these " preserves " at the back of Magdalena opportunities were
afforded me of investigating the subject. Here the larger wood
was made up entirely of Myrica faya, Laurus canariensis, and Erica
azorica. The two first-named trees commonly attained a height of
from thirty-five to forty feet and a diameter of from twelve to fifteen
inches, and those of Erica azorica a height of twenty-five feet and
a diameter of eleven or twelve inches. The Faya trees occasionally
exceeded forty feet, the maximum being fifty feet. In the gardens
around Ponta Delgada they grow to a height of from thirty-five to

396 PLANTS, SEEDS, AND CURRENTS

forty feet. The Erica trees evidently need the protection of a wood
to attain their maximum size. Though a few of them in these pre-
serves must have measured between thirty and thirty-five feet, it was
apparent from the number of leaning and fallen trees that this was
their limit.

It does not seem, however, that the present Juniper trees anywhere
approach the size attributed to the " cedros " of the original forests.
On Pico a height of fifteen or sixteen feet and a diameter of fifteen
to eighteen inches (in very rare cases twenty inches) represent my
maximum measurements. Rarely does the Azorean Juniper grow
straight, the trunk being twisted and bent. It is likely that the
finest specimens exist on the uplands of San Jorge. Judging from
a photograph kindly taken in my interest by Colonel Chaves, they
might there attain a height of eighteen or twenty feet. Mr. Ogilvie-
Grant mentions the *' grand old Juniper trees " in the higher levels
of the same island (Novitates Zoologicce, XII., 1905).

The Causes of the Destruction of the Original Forests. —
That the volcanic eruptions of early times played an important part
in the destruction of forests in the Azores is highly probable. The
old timber trees, as before described, are now found buried beneath
their ejectamenta. In the early part of the occupation by man,
namel}^, in the fifteenth and sixteenth centuries, the devastation
of the forests from this cause must have been tremendous, and it is
likely that the older outbreaks produced similar results. Since
pumiceous tuffs strew the surface of San Miguel and are often exposed
in sections a hundred feet in thickness, both in the high and in the
low levels, we cannot help reflecting that the land-surface at such
times must have been largely deprived of its covering of vegetation.
The outbreak that occurred in the valley of Furnas in 1630 well
illustrates what must have often taken place before. For three
days and nights the ashes fell over all the island of San Miguel,
covering the surface to a depth ranging from seven to twenty feet,
and in many places destroying all the vegetation (Walker, pp. 61,
214). Even greater desolation must have resulted from the eruption
of 1445, when the highest eminence of the island at its western end
was destroyed, leaving the great crater of the Seven Cities as its
mark {Ibid., pp. 51, 57, etc.). The adjacent seas were covered with
fields of floating pumice and immense trunks of trees, through which
Cabral, the Portuguese navigator, made his way when approaching
the island. It is probable that in the relatively recent activity of the
volcanic forces in the Azores we have an explanation of the curious
fact referred to in a later page of this chapter, that of the three
Macaronesian groups, the Azorean, the Madeiran, and the Canarian,
it is the group that is farthest from the mainland, namely, the Azores,
that displays the least evidence of differentiation in its flora.

Yet it is likely that the plant world would have of itself regained
much of its hold on the Azores, if it had not been for the arrival
of the European. Man and his animals have completed the destruc-
tion of the original forests. In fact. Colonel Chaves, whose opinion
would carry the greatest weight, seeks for the exclusive factor in
the disappearance of the forests in the destruction made by the
inhabitants for constructions, fire, and exportation " (letter cited).

THE AZORES

397

The islands were discovered between 1432 (Santa Maria) and 1452
(Flores), and the early settlers displayed much energy in clearing
the forests. Goats, hogs, and cattle were soon introduced, and they
doubtless effectively assisted man in " the rapid and total extinction
of these grand denizens of the forest, and with them probably of
interesting plant and insect life " (Walker, p. 25). It is stated
that as early as 1526 the coasts of San Miguel were all under cultiva-
tion, and that sixteen parishes and six villages had been founded.
According to the Traveller'' s Guide to MichaeVs, by F. S. Mayor (pp. 18,
19, Ponta Delgada, 1911), from which the facts just quoted have been
taken, the earliest cultivation was of cereals and sugar-cane, the latter
succumbing in 1560 to disease. From 1520 to 1640 great quantities
of the Woad plant (Isatis tinctoria) were raised and exported ; and,
as we learn from the same authority, flax was cultivated between
1750 and 1764. In Linschoten's time (about 1589) the inhabitants
of San Jorge, as they do at present, chiefly raised cattle and conveyed
their produce to the islands near (see Purchas). One can imagine
the extensive importation of weeds that must have been involved
in the endeavours of the earlier colonists to develop the resources
of the group.

In the course of time, so rapidly was the clearing of the woods
effected in the more populous islands, like San Miguel and Terceira,
that they began to look to the other islands for their timber. Thus
Flores supplied Terceira with " cedars," and Pico seems to have been
from the earliest days of the occupation a source of timber for the
neighbouring islands. Some of the most valuable woods were sent
to Portugal in these early times. Thus Dr. Webster, whose descrip-
tions of St. Michael was published in 1821, states that considerable
quantities of " the wood of Pico," apparently a species of yew,
were formerly sent to Lisbon, where it was manufactured into work-
tables, desks, etc.

Whilst the earlier colonists despoiled their timber forests for
erecting their houses, churches, and for similar purposes, they also
employed the timber for firewood. Linschoten writes that in his
day, namely, in the latter part of the sixteenth century, the wood
of the " cedar " (Juniper) " is the commonest wood that they use
to burne in those Countries, whereby it is the wood that with them
is least esteemed, by reason of the great quantity thereof " (Purchas,
vol. 18, p. 366). This practice has continued down to more recent
times. The Bullars state that the " small stunted cedars " were
so common on Flores in their time (1839) that their wood was used
for heating the ovens, the pleasant smell from the cedar smoke
of the cottage fires being noticeable outside the houses. In Pico
at the present day the wood of the Juniper is extensively employed
for the staves and bottoms of the milk buckets.

The need of fuel through the centuries and the requirements for
fruit-boxes in later times have sealed the fate of the original forests.
The demands of the fruit-trade were so great that at the time of
which Walker wrote, about 1880, trees fifty years old were seldom
met 'with on San Miguel. Those demands have passed away with
the trade; but the need for fuel is of course insistent. Pico has
been for generations the principal source of fuel for the neighbouring

398 PLANTS, SEEDS, AND CURRENTS

island of Fayal. At present a regular trade in Pico firewood exists
between Horta and the towns and villages on the Pico side of the
straits. There is but little attempt in the way of re-foresting the
island of Fayal. Writing of a time so long ago as 1839 the Bullars
remarked that " to such an extent has this short-sighted destruction
been carried in Fayal that, with ample room for plantations, the
principal supply of fuel is derived from Pico " (II., 8).

Firewood is the eternal question with these people ; but it is only
used for cooking their food, the foliage serving as fodder, the leafy
branches as litter in their stables, and the branches of the Ling
(Calluna vulgaris) and the Tree-Heath {Erica azorica) as brushwood.
The procuring of these materials seems to be one of the principal
occupations of their lives. On the lower slopes of the great mountain
of Pico one meets all through the year a constant string of men,
women, and bullock-drawn carts carrying loads of Erica azorica^
Calluna vulgaris^ Myrica faya, Laurus canariensis, Ilex perado, etc.,
the foliage of the last-named plant being cut in quantity for mule
fodder. Withal, there is no attempt at renovation of the sources
of supply. The land is allowed to remain undisturbed for several
years, and the owner makes considerable profit by selling it with
the wood standing, receiving it back when the wood is all felled.
Faya trees attain a diameter of five or six inches in from eight to
ten years, so that the growth of one of the most abundant and most
useful of the trees can scarcely be said to be very rapid.

The lower wooded slopes of the mountain of Pico reaching to the
government lands, 3000 to 4000 feet above the sea, are all private
property. Low walls of loose lava blocks separate the different
ownerships, the poor man having a small patch and the rich man
a large one. These properties are handed down from parents to
children, and the rights are rigidly observed. They may remain
in the same family for generations. A bequest of a small patch of
woodland for some poor widow is as much a necessity of her existence
as a dwelling, and willing hands help her to bring the faggots down
the mountain side, if she is old and feeble. A large amount of the
carrying is done by the women, whilst the men do the felling. Coal
at my time was only used by some of the better-class Picoese. The
poorer people of the larger coast towns, like Magdalena, usually
purchased their wood off the land from the owner, felled it themselves
and carried it home, about six dollars' worth lasting them a year.

The Affinities of the Native Flora of the Azores. — The
characteristic flowering plants of the woods, of the moors, of the
ponds and lakes, and of the coast, exhibit in a progressive scale a
gradually extending connection with the outer world. This is well
brought out in the tables following these remarks. Whilst the shrubs
and trees of the woods are for the most part non-European, and
either exist in the other two Macaronesian groups (the Canaries
and Madeira) or are represented there by closely related species,
the plants of the upland moors and of the ponds and lakes are nearly
all European species, that rarely occur either in the Canaries or in
Madeira. The shore plants on their part are fairly well distributed,
both in Europe and in the other two groups; and nearly half of
them are also North American. The North American connections

THE AZORES

399

of the native flora are almost all of them European species; and,
as might be expected from what has been said above, they are least
evident with the plants of the woods and most pronounced amongst
those of the sea-border and of the ponds and lakes.

The restrictions of most of the characteristic plants of the woods
to the Macaronesian islands, the extension of nearly all those of
the upland moors to Europe, and the common dispersion on both
sides of the Atlantic of the plants of the seashore and of the ponds
and lakes, illustrate a principle of wide application to insular floras —
a principle, however, that is often best exemplified in tropical regions.
The varying degrees of isolation thus implied reflect, as will be shown
later on, the differences in the histories of the dispersing agencies
in stocking with their plants the woods, the moors, the ponds and
lakes, and the seashores. The currents have been for ages unceas-
ingly at work, directly and indirectly, in carrying seeds from one
coast to another; and as a rule in tropical latitudes the specific
connections kept up between the shore floras of different regions
can be mainly ascribed to their influence. In a similar manner
migrant waterfowl have sustained the connections of the plants
of the river, the lake, and the pond, over great areas of the globe.
In a like fashion, though to a less extent, birds of the grouse family
have kept the plants of the mountain moors of distant regions in
touch with each other. On the other hand, the dispersing activities
of forest-frequenting birds, as far as oceanic islands are concerned,
have been more and more restricted in the course of ages. The bird
finally comes to stay, and both plant and bird differentiate together.

The foregoing subject is dealt with in the penultimate chapter
of my book on Plant Dispersal ; but it is one, the importance of
which was long since recognised by Godman in his work on these
islands (p. 339). The principles involved have been unable to find
their full expression in the islands of the Azores by reason largely
of the lesser antiquity of those islands as compared with such an
ancient group as that of the Hawaiian Islands in mid-Pacific. There,
the impress of a far greater antiquity lies on the flora, and where
species have been difierentiated in the Azores genera have been
developed in Hawaii. As shown in the work above named, it is
on the forested mountain slopes of the Hawaiian Islands that most
of the peculiar genera and peculiar species, both of plants and birds,
are to be found. Here the agencies of trans-oceanic dispersal have long
since ceased to act. A later suspension of these agencies is indicated
by the plants of the mountain moor, which are generically connected
with regions on both sides of the Pacific, but are usually specifically
distinct. Yet, unless within recent times, there has been no suspen-
sion in the activity of migrant waterfowl as seed-carriers to the
Hawaiian group, and as a result we find in the waters and at the
sides of ponds and rivers plants that are widely distributed over the
world. Lastly, there are the beaches, where, through the action
of the currents in the run of the ages, we find several of the littoral
plants characteristic of the tropical shores of Malaya, continental
Asia, Africa, and America. We thus perceive that the Azorean
and Hawaiian floras exhibit the same progressive scale of connections
with the outer world, which are least with the plants of the woods.

400 PLANTS, SEEDS, AND CURRENTS

freer with the plants of the upland moor, and more or less unrestricted
with the aquatic plants and with the plants of the seashore.

Though the contrasts in the differentiation of the Azorean and
Hawaiian floras are largely bound up with the differences in the
antiquity of the two archipelagos, the much greater isolation of the
Hawaiian group, which lies some 2000 miles from the nearest main-
land, has doubtless had a potent influence. Yet antiquity alone may
largely counteract the effects of contiguity to a continent. The
Canaries, for example, are evidently of much greater age than the
Azores, and to this circumstance we might attribute the fact that
as many as 30 per cent, of their native plants are peculiar, whilst
only 10 per cent, are endemic in the Azores. Yet only fifty-five
miles of open sea separate the Canaries from the African coast,
whilst about 800 miles intervene between the Azores and the nearest
mainland, the coast of Portugal. So w^ith the Galapagos Islands,
which are removed about 500 miles from the coast of Ecuador, half
of the native plants are endemic. It is therefore evident that an
influence more potent than that concerned with distance from the
mainland may affect the endemism of some insular floras. Presum-
ably this is often that of antiquity.

Before proceeding with the discussion of the affinities of the native
flora of the Azores, I will give in tabulated form the distribution
of the most characteristic plants grouped according to their station.
The affinities of the individual groups will then be dealt with, and
this will be followed by a comparison of the Azorean, Madeiran, and
Canarian floras, as far as it can be focussed in a contrast of the vegeta-
tion of the Peak of Teneriffe and of the great mountain of Pico.

distbibution op characteristic native flowering plants of the
Azores outside the Group

I

Plants of the Woods

Canaries

Madeira

Africa

Europe

North
America

Eemarks

Hypericum foliosum
(Ait.)

Probably allied to a
species of Madeira,
H. grandifolium. (See
Watson.)

Ilex perado (Ait.)

+ ?

+

Allied to a Canarian
species, if not in the
group (Watson).

Rhamnus latifolius
(Herit.)

+

Lowe is the authority
for its Madeiran habitat.

Prunus lusitanica (L. )

+

+

+

Rubus f ruticosus (L. )

+

+

+

+

A segregate species
usually named discolor
by English botanists
(Watson). (SeeTrelease.)

THE AZORES 401

Plants of the Woods (cont.)

Canaries •

Madeira

Africa

Europe

North
America

Remarks

Hedera canariensis
(Willd.)

+

+ ?

Near H. helix (Wat-
son).

Arceuthobium oxy-
cedri (M.B.)

+

+

+

The authorities for its
distribution are the In-
dex Kewensis and Arc-
angeli's Flora Italiana.

Viburnum tinus (L.)

+

+

Trelease describes the
Azorean form as a
variety of F. tinus under
the name of suhcordatum.

Vaccinium cylindra-
ceum (Sm.)

Closely allied to a
Madeiran species V.
maderense. (See Wat-
son.)

Erica azorica
(Hochst.)

Picconia excelsa
(DC.)

+

+

Notelcea excelsa (Webb)
is a second name.

Myrsine africana (L.)

+

Widely distributed in
Africa and Central Asia.

Daphne laureola (L.)

+

+

Laurus canariensis
(Webb)

+

+

The Persea azorica of
Seubert.

Persea indica (Spr.)

+

+

Laurus indica in
Lowe's work.

Euphorbia mellifera
(Ait.)

+

+

The Azorean variety
is Stygiana (Watson).

Smilax

Trelease divides the
Canariensis of Watson
into Excelsa, L., and
Divaricata, Sol.

Myrica faya (Ait.)

+

+

Juniperus brevifolia
(Hochst.), a var. of
J. oxycedrus (L.)

+

+

+

+

Seubert's view that
J. brevifolia stands to
J. oxycedrus as J. nana
to J. communis is
adopted. The distri-
bution given is that of
J. oxycedrus.

Taxus baccata (L.)

+

+

+

+

Lowe is the authority
for its being Madeiran.

D D

402 PLANTS, SEEDS, AND CURRENTS

Distribution of Characteristic Native Flowering Plants op the
Azores outside the Group {cont.)

II

Plants of the Upland Moors

Canaries

Madeira

Africa

Europe

North
America

Remarlcs

\

Viola palustris (L.) |

+

Polygala vulgaris (L. ) j

+

i

Potentilla tormen-
tilla (Wats.)

+

+

Hydrocotyle vulgaris
(L.)

+

Calluna vulgaris (S.)

+

+

+

Menziesia polifolia j
(Sm.)

+

1
1

Erythraea massoni
(Sw.)

Connected by some
with a Canarian species.

Sibthorpia europaea
(L.)

+

Occurs in the Abys-
sinian highlands
(Hooker's Marocco, p.
422).

Thymus serpyllum
(L.), var. angusti-
folius (Bois.)

+

+

+

The distribution re-
fers to the species.

Lysimachia nemo-
rum (L.)

+

The separation of L.
azorica (Hornem.) is not
here adopted.

Though regarded as
distinct species by both
Watson and Trelease,
they are united in the
Index Kewensis and by
Seubert as well as by
Pax and Knuth in the
Pflanzenreich.

Anagallis tenella (L.)

+

+

Luzula purpureo-
splendens (Seub.)

Carex flava (L.)

+

+

+

Also Asiatic.

THE AZORES

403

Distribution of Characteristic Native Flowering Plants op the
Azores outside the Group {cont.)

Ill

Plants of the Ponds and Lakes

Canaries

Madeira

1

Africa

Europe

Nortli
America

Remarks

Callitriche aquatica
(L.)

+

+

+

+

World-wide.

Peplis portula (L.)

+

+

Littorella lacustris
(L.)

+

Potamogeton poly-
gonifolius (Pourr.)

+

+

+

Also Asiatic.

Scirpus palustris (L.)

+

+

+

+

Also Asiatic.

Scirpus multicaulis
(Sm.)

+

Scirpus fluitans (L.)

+

Scirpus savii (S. and
M.)

+

+

Watson is here fol-
lowed. Ball gives it as
on the Great Atlas.

Carex stellulata
(Good.)

+

+

Also Asiatic, Aus-
tralian, etc.

404 PLANTS, SEEDS, AND CURRENTS

Distribution of Characteristic Native Flowering Plants of the
Azores outside the Group {cont.)

IV

Plants of the Sea-coasts

Canaries

Madeira

Africa

1

Europe |

North
America

Remarks

Cakile edentula
(Bigel.)

4- f

_i_
1

For Madeira see page
185. Probably intro-
duced into Azores in
ballast.

Silene maritima (B.
and H. Handbook)

+

+

+

Spergularia marina
(Watson)

+

+

+

Also Asiatic.

Mesembryanthe-
mum ?

See page 384.

Crithmum mariti-
mum (L.)

+

+

+

Solidago sempervi-
rens (L.)

+

Also indigenous in
Bermuda.

Campanula vidalii
(Watson)

See page 427.

Erythrsea maritima
(Pers.)

Ipomoea carnosa (R.
Br.)

+

+

Occurs also in the
Hawaiian Islands.

Hvoscyamus albus
^(L.)

+

+

+

Plantago coronopus
(L.)

1

+ +

Salsola kali (L.)

+

+

1

Also Asiatic.

Beta maritima (L.)

+

+

, +

+

Polygonum mariti-
mum \Li.)

+

+

1

; +

1

+

+

Euphorbia azorica
(Hochst.)

+ ?

In De Candolle's Pro-
dromus regarded as a
variety of E. pinea,
L,, which occurs in
South Europe, North
Africa, and Madeira.

Euphorbia peplis (L.)

+

+

Juncus acutus (L.)

+

+

+

+

Note. — With one or two exceptions the African localities are North African, though
several of the plants have a wider distribution in the continent.

THE AZORES

405

Summary of the results given for the characteristic plants of the
Azores in the foregoing tables.

Macaronesian
exclusively

African

European

North American

Remarks

Total

Peculiar
to Azores

Plants of the woods
(total 20)

12

3

7

7

2

Two of the peculiar
Azorean species are
closely allied to Ma-
deiran species.

Plants of the upland
moors (total 13)

2

2

4

11

3

Plants of the ponds
and lakes (total 9)

0

0

5

9

4

Plants of the sea-
coast (total 15)

1

1

7

13

6

The species of Cakile
and the doubtful species
of Mesembryanthemum
are not included.

Note. — Macaronesia is here taken as comprising the Azores, the Madeiras, and the
Canaries. The total under this head includes not only the Azorean plants occurring
in the Canaries and Madeira (one or both), but also the peculiar Azorean plants
which are indicated in the next column.

With one exception the African localities are North African, though several of the
plants have a wider distribution in the continent.

(A) The Affinities of the Characteristic Plants of the Woods. — Although
the ancestors of the non-European species were in all probability
originally derived from Europe, they doubtless belong to an early
period in the plant- stocking of the group, the connection with their
home having been long since broken off. But this rupture has only
affected the majority of the plants, about a third of those named
in the foregoing list being European species. Three of them, Daphne
laureola. Viburnum tinus, and Juniperus oxycedrus, grow on the slopes
of the Great Atlas at altitudes of 4000 to 6500 feet (Ball), whilst Taxus
haccata is at home in the mountains of Algeria (Arcangeli).

The possibility thus presents itself that the Azores derived some
of their European plants by way of the mountains of North-west
Africa. But there is reason for the belief that the other two Maca-
ronesian groups, the Canaries and the Madeiras, have received
similar accessions to their floras from the Atlas Mountains. Thus,
to take the Canarian forest flora, we have in Daphne gnidium a
European species that is associated on the slopes of the Great Atlas
with Daphne laureola, and in Viburnum rigidum a species which
from its resemblance to the Azorean variety of V, tinus might be
by some regarded as possessing the same parentage (see on this
point Trelease, p. 118). Then again the Canarian flora owns in

406 PLANTS, SEEDS, AND CURRENTS

Juniperus oxycedrus a Great Atlas tree. Not more than 250 miles
separate the western extreme of the Atlas Mountains from the Canary-
Islands, and it would be strange if the woods of that archipelago
had not received important accessions from that elevated region.
Much of what has been said of the Canarian forest flora would apply-
also to Madeira. In this case the Yew (Taxus haccata) and the
Juniper (J. oxycedrus) could have found their nearest source in the
Western Atlas.

As regards the possibility of the Azorean woods having received
some of their European species from North-west Africa as well as
from South-wTst Europe, one may be prepared for much when we
reflect on the very singular African connection displayed by one
of the most predominant of the shrubs, namely, Myrsine africana.
It is a native and often a mountain plant of Inter-tropical and South
Africa, Arabia, and Central Asia. It is not even at home in Madeira
and the Canary Islands, its nearest known habitats being in Angola
and Abyssinia. Its small berries are well suited for dispersal by
frugivorous birds; but its isolated occurrence in the Azores is one
of the puzzles of the flora.

But by far the most important feature in the affinities of the
characteristic plants of the Azorean woods is indicated in the fact
that, whilst mainly non-European, they are largely Canarian and
Madeiran. We are not so much concerned here with statistical
results, such as are presented at the end of the previous table, but
with the fact that vdth. one exception, that of Myrsine africana,
all the trees and shrubs that are most abundant are either Canarian
or Madeiran, or are presented in one or both of those two groups
by closely allied or similar species. They are Canarian in a special
sense, since they are for the most part confined to the middle zone
or Laurel belt of Teneriffe, which lies between the levels of 2000 and
5000 feet. That their general facies was Canarian was recognised
by the ™ter when exploring the Azorean woods, after a previous
acquaintance on Teneriffe vdth. the woods situated between 2000
and 3000 feet above the sea in the Laguna and Taganana districts.
In these Canarian woods flourish the same two Laurels, Laurus
canariensis and Persea indica, the same species of Myrica (M. faya),
a similar Tree-Heath (Erica arhorea), a Holly closely allied to or
identical with the Azorean Ilex {I. perado), allied species of Rhamnus,
Vaccinium, and Viburnum, and among the climbers the same species
of Hedera and Smilax. Excluding the special Canarian element,
the list given by Christ of the characteristic trees and shrubs of the
Laurel woods of Teneriffe might in most respects pass for one of
those of the Azorean woods on the slopes of the great cone of Pico ;
but this is a subject that will be again noticed when we compare
the zones of vegetation on the slopes of these two great volcanic
mountains.

The Madeiran aspect of the Azorean woods is seen in many ways.
Here again, after excluding the special Madeiran element, the principal
indigenous trees and shrubs named by Lowe for the lower woods
and for the Laurel and Heath zone, 2500 to 5500 feet above the sea,
include many of those that give character to the Azorean woods.

THE AZORES

407

Here in the lower woods are Myrica faya, Ehamnus latifolius (now very
rare), and Euphorbia mellifera, as well as a representative species
of Hypericum (H. grandifolium). In the upper woods grow Laurus
canariensis, Persea indica, Ilex perado, Picconia excelsa (now very
rare), a representative Tree-Heath {Erica arhorea), and a species
of Vaccinium (V. maderense) closely allied to the Azorean species.
The thickets of Tree-Heath and of Vaccinium, in which thrive the
two Madeiran Hollies {Ilex perado and /. azevinho), must together
with the Laurels and the Fay as often give an appearance very
Azorean to the remains of the original Madeiran woods. We will
now proceed to discuss briefly the affinities of the other groups of
characteristic Azorean flowering plants.

(B) The Affinities of the Characteristic Plants of the Upland Moors, —
Of the thirteen plants named in the list eleven are European and two
are endemic. There is no African or North American connection
that is not also European. There are seemingly hardly any of these
plants in the Canaries and not many in Madeira; and when we
reflect that only Thymus serpyllum appears to be represented on
the Great Atlas range, namely, on the higher slopes, we are driven
to the conclusion that the Azores derived their moor plants from
Southern Europe.

(C) The Affinities of the Characteristic Plants of the Ponds and
Lakes. — The conclusion formed for the plants of the moors applies^
here with greater force. All the species are European, and this;
disposes of any special connection either with Africa or North
America. Then, again, few of them have been found either in Madeira
or in the Canaries. We must therefore look to South-western Europe
for the source of the Azorean aquatic and subaquatic plants.

(D) The Affinities of the Characteristic Plants of the Sea-coast. —
Here, though predominantly European, the species are well repre-
sented in North America as well as in the Canaries and Madeira,
though, if we exclude Cakile edentula, which was probably introduced
in ballast, the only North American species that is non-European:
is Solidago sempervirens. The case of Campanula vidalii probably
raises other issues. As concerns Euphorbia azorica it would be safer
to give it a varietal value than to regard it as a distinct species.

A Comparison of the Zones of Vegetation on the Great
Cone of Pico with those on the Peak of Teneriffe and on thk
Island of Madeira. — The contrasts between the zones of vegetation
in the Azores and the Canary Islands can be focussed in a comparison
between the great mountain of Pico and the Peak of Teneriffe.
The differences between the zones on Teneriffe are so striking that
all observers agree fairly well in their accounts of them, whether
in the case of Von Buch in the early part of last century or in that
of Christ in the latter part of it ; and since the present writer made
acquaintance with the plants of the lower two zones during a short
visit to the island in the month of February, he is able to approach
the subject with some confidence.

The lowest zone on Teneriffe, the region below the clouds (as
Christ designates it), reaches up to 2000 or 2500 feet. It is the
African zone with all its strange-looking plants, the region of steppe

408 PLANTS, SEEDS, AND CURRENTS

vegetation. On its rocky slopes bushes prevail. Here we see the
Cactoid Euphorbias, the curious rubiaceous Plocama pendula with
the habit of a Casuarina, many shrubby Compositce, such as Kleinia
neriifolia, as well as several kinds of boragineous plants of the genus
JEchium and a score of species of Statice. Here the Canarian palm
^PhcBuix canariensis) is at home; but probably next to the Cactoid
Euphorbias the Dragon-trees (Draccena draco, dealt with in Note 31
-of the Appendix) gave most character to the larger vegetation in the
early days. Amongst the most conspicuous and interesting of the
lesser plants are the fleshy-leaved Crassulacece. On the steep slopes
of the barrancos and on the faces of the lofty coast-cliffs they present
themselves often as large flat rosettes that may measure as much as
twelve or even fifteen inches across. Nowhere else in the world,
writes Hemsley in his account of Christ's investigations, is there
such a concentration of this class of plants, no fewer than fifty-two
species having been enumerated by Christ, mostly belonging to the
genus Sempercivum.

Then follows, between 2000 and 5000 feet, the region of clouds
and of rains, the zone of the Laurel forests, where we notice several
Azorean trees and shrubs, such as Laurus canariensis and Persea
indica among the Laurels, as well as Myrica faya, Picconia excelsa,
a simflar Tree-Heath (Erica arborea), and the same or allied or
representative species of Ilex, Rhamnus, Smilax, Viburnum, and
Vaccinium, Amongst the several trees and shrubs that are not
found in the Azores are the two Laurels, Oreodaphne fcetens and
Phoebe barbusana, a species of Arbutus, and a species of the American
genus, Clethra. The American elements in the Canarian flora will
be again alluded to.

Above the Laurel woods we enter the Pine belt, which is most
characteristic of the levels between 5000 and 6500 feet. This was
also the zone of the Jumper, now, as Christ remarks, almost exter-
minated on Teneriffe. It is highly probable that the Juniper
{Juniperus oxycedrus) was once associated with the Pine (Pinus
canariensis) in considerable quantity; but the value placed on its
timber, not only by the colonists but also by the aborigines, has
resulted, according to Christ and others, in its practical extinction.
However, scattered individuals still exist in the upper portion of
the Pine belt; but it is extremely probable that it had originally
much the same range as the Pine. It would seem that it still
•exists at altitudes of about 4000 feet on Palma, another island of
the group, and that it once grew near the summit of one of the highest
peaks of the island, the Pico del Cedro, which rises 7470 feet above
the sea (see Bolle as quoted by Christ, and Samler Brown's Guide
to the Canary Islands, 1905, pp. 1, 10). We might expect that the
original vertical range of Juniperus oxycedrus on Teneriffe was
about a thousand feet higher than it is on the slopes of the Great
Atlas, about three degrees farther north, where it was placed by
Hooker and Ball (p. 433) at 4000 to 6500 feet.

Beyond the Pine belt is a belt covered with the " codeso " (Adeno-
carpus viscosus), a leguminous shrub that extends to about 7000 feet.
This plant then gives place on the pumice-stone plains of the Canadas

THE AZORES

409

to the " retama " (Spartocytisus nuhigenus), a broom, which with
occasional herbs reaches to nearly 11,000 feet. So characteristic
is the broom of this elevated region that the pumice plains are known
as the Llano de la Retama."

Before contrasting the zones on Teneriffe with those on Madeira
and in the Azores, we will first determine what we ought to expect,
having regard to the difference in latitude (Teneriffe, 28° 17' N. ;
Madeira, 32° 44'; Pico, 38° 28') and the associated differences in
climate. From the data given below it will be apparent that in
response to the cooler climatic conditions we should expect in the
case of Pico no African zone, and in its place the extension of the
Laurel woods to the coast. In the case of Madeira we should look
for intermediate features in the vertical range of the zones. The
African zone would be considerably restricted, and the lost ground
would be occupied by the Laurel woods in their descent towards
the coast.

Taking the rate of change of the mean temperature at rather over
three degrees, Fahrenheit, for each thousand feet, the difference in
the annual mean temperature near the sea-level at Teneriffe and
Pico, which is about seven or eight degrees (69-61), would represent
some 2000 or 2500 feet. From this it follows that the warm climatic
conditions that prevail below 2000 or 2500 feet on Teneriffe, or, in
other words, those of the African zone, would not exist on Pico;
whilst the Laurel woods, which succeed the African zone on Teneriffe,
would on Pico descend to the coast. In the case of Madeira, where
the mean annual temperature near the sea-level (about 66° F.) is
some three or four degrees lower than at Teneriffe, the corresponding
difference in altitude would be 1000 or 1200 feet. As the result,
the upper limit of the African zone in Madeira, instead of lying
2000 or 2500 feet above the sea, as on Teneriffe, would only attain
half that elevation on the Madeiran slopes, and the Laurel woods
would descend to a similar extent.

When we come to the facts, and compare in the first place the
zones of vegetation on Teneriffe and on Pico, the results may soon
be stated. Pico owns no African zone. Where the cultivator has
allowed it, its lower woods so Canarian in their character, in their
Laurels, their Fayas, and their Tree-Heaths, instead of lying some
2000 or 2500 feet up the slopes, as on Teneriffe, descend to the vicinity
of the coast. So also its upper woods, where the Azorean repre-
sentatives of the Canarian Juniper (J. oxycedrus) give character to
the vegetation, indicate a similar downward displacement of some
2000 feet or more, as compared with the elevation of the original
Juniper zone on Teneriffe. The Canarian Juniper zone evidently
lay above 4000 feet ; whilst the Azorean zone of Junipers descends
to 2000 feet.

But there is no belt of Pines on Pico. It cannot be argued that
the suitable soil-conditions and the requisite elevation for the genus
would not be found on the barren slopes of lava and cinders on the
higher levels of the mountain, since from the association on Teneriffe
of the Canarian Pine with Juniperus oxycedrus it is apparent that
the place of the Pine on Pico would be at elevations 2000 or 2500

410 PLANTS, SEEDS, AND CURRENTS

feet lower than on Teneriffe, that is to say, between 2500 and 4500
feet above the sea. Here, usually under good soil-conditions, the
Juniper is at home on Pico, but there are no Pines. The absence
of the Pine from Pico, and from the Azores as a group, is a very
pregnant fact in the history of the plant-stocking of the archipelago.
A brief comparison of the summit vegetation of the great volcanic
mountains of Teneriffe and of Pico, as well as of Madeira, will follow
the description of the zones of vegetation on the last-named island.

In the case of Madeira, sufficient materials for the comparison of
its zones of vegetation are supplied by Lowe. The lowest or tropical
zone, corresponding to the African zone on Teneriffe, extends accord-
ing to this authority only 700 feet up the slopes. He names it the
Cactus and Banana zone, and names among its indigenous plants
Draccena draco and Euphorbia piscatoria (the Dragon Tree and arbores-
cent Euphorbia of the lowest Canarian zone), with species of Semper-
vivum, and the sapotaceous tree, Sideroxylon mermulana ; but we
may infer that both in its extent and its characters the lowest
Madeiran zone is a poor representative of the Canarian zone. From
the data given by Lowe we can infer that the woods which originally
clothed the slopes of Madeira from five or six hundred feet above the
sea to within a few hundred feet of the summit, the altitude of which
is about 6100 feet, were in the main the representatives of the Laurel
woods of Teneriffe, which there exist at levels of 2000 to 5000 feet.
In their lower levels flourished, as in the Azores, the Faya tree {Myrica
faya), and in the upper levels the Azorean Laurels Laurus indica and
L, canariensis), all characteristic of the Canarian woods. They were
associated with the Tree-Heath (Erica arhorea) of Teneriffe, Rhamnus
glandulosa of the same island, the Tree-Euphorbia (E. mellifera),
and Picconia excclsa of the woods of Pico and Teneriffe, besides
shrubby species of Hypericum and Vaccinium, representing pre-
dominant plants of the Azorean and Canarian woods. But a feature
of the Madeiran as well as of the Canarian woods, a feature not
possessed by those of the Azores, is the presence of shrubs and trees
of the American genera, Clethra, Cedronella, and Bystropogon, etc.,
to the significance of which allusion will subsequently be made.

There was originally a Junipet zone in the higher levels of the
Madeira woods, such as there was once on Teneriffe, and such as
exists now on Pico. Though now nearly exterminated on account
of the value set on its timber, Juniperus oxycedrus, as Mr. Johnson
tells us (EncycL Brit. 9th edit. XV., 180), was formerly abundant,
and grew to a height of forty or fifty feet. Its lower limit was pro-
bably intermediate between that of the Juniper zone on Pico (2000
feet), and on Teneriffe (4000 feet), so that probably it would have
flourished at levels above 3000 feet. Walker, in his book on the
Azores, speaks of this Juniper as growing to a stately size in the
mountain fastnesses of Madeira. Indigenous Pines are absent from
Madeira as well as from the Azores, and the same difficult question
is here raised. Since Pinus pinaster has been extensively planted
on the Madeiran slopes, the absence of the genus cannot be due to
unsuitable conditions.

It is remarkable that whilst the woods of Pico, Madeira, and

THE AZORES

411

Teneriffe possess many features in eommon, the plants that have
found a home on their summits differ greatly. We have seen that
the plants which have reached the summit of the great cone of Pico,
the Heather (Calluna vulgaris), the Heath (Menziesia polifolia), the
Thyme (a variety of Thymus serpyllum), the grasses, etc., have all
climbed up from the moors below. This would have been impossible
either on Teneriffe or Madeira, on account of the absence of moors
of this description. Yet in the queer little gathering of half a dozen
native plants, which Lowe describes as having found a refuge on
the rocky crags of the summit of Madeira, there is a small effort
in this direction. After removing from his list Cerastium tetrandrum
(Curt.), as probably an introduced weed, there remain Arenaria
serpyllifolia, Erica cinerea, Viola paradoxa, Armeria maderensis,
and Avena marginata, the three last being first described by Lowe
as peculiar to the island. Coming to the scanty vegetation of the
high levels of Teneriffe, it is to be again observed, that apart from
the perennial herbs (Arahis alhida, etc.) it is the Retama broom
(Spartocytisus nubigenus) that gives a character to the pumice-stone
plains of the Canadas between 7000 and 9000 feet above the sea,
a leafless shrub that climbs the steep lava slopes of the terminal
cone to a height of 11,000 feet. The history of the Retama in this
elevated area is implied in a remark of Hooker, that its Moorish
name has come to be used by botanists for a small group of brooms,
containing a few nearly allied species, that are widely spread through-
out the region extending from Spain to the Canary Islands (Marocco
and the Great Atlas, p. 27). A Violet, known as Viola teydensis and
peculiar to the peak, clings to the soil at the upper edge of the Llano
de la Retama, as the pumice-stone plains are called. Above this
level, pyrites Johnson {Encycl. Brit. 9th edit. IV., 797), there is nothing
but a little lichen.

We have remarked that the peculiar feature of the summit vegeta-
tion of the great cone of Pico, as compared with the Peak of Teneriffe
and with Madeira, is that it is all derived from the moors below.
This brings us to another distinctive feature in the zones of Pico.
The wet and dry moors, which are so conspicuous around the middle
levels of the mountain of Pico, having been formed at the expense
of the upper woods or the Juniper zone, seem scarcely represented
on Teneriffe and Madeira, hardly any of their characteristic plants
being there present. This contrast is well reflected in the differences
in the Sphagnum floras of the three groups, as brought out in Warn-
storf's monograph on the Sphagnacece {Das Pflanzenreich, 1911).
Whilst in the Azores there are nine known species of Peat-mosses, of
which two are peculiar to the group, there seems to be in each case
only a single wide-ranging species in Madeira and the Canaries, a
fact that points to prevailing unfavourable conditions for the develop-
ment of Sphagnum moors in those islands.

The Plant-Stocking of the Macaronesian Islands. — But to
return to our general comparison of the floras of the Macaronesian
islands, there is a wider outlook of the question, such as Hooker
presented in his Lecture on Insular Floras (1866), and in his discussion
of the Canarian flora in his later work on Marocco (1878), and such

412 PLANTS, SEEDS, AND CURRENTS

as Christ offered some years after in his contribution to Engler's
Botanische Jahrbucher (1885). According to Christ, the oldest
constituents of the Macaronesian floras, such as occur in the Canaries
and to a less degree in Madeira, are the African plants, as examples
of which the Cactoid Euphorbias and the Dragon-trees (Draccena
draco) are amongst the first to attract the stranger's eye, when he
first visits these islands. Then followed the invasion by Asiatic
plants, now typefied by genera like Phoebe and Visnea, that are
identical with or closely allied to genera now existing in the warm
regions of Asia. Most of the peculiar Canarian genera appear to
be connected with these early African and Asiatic invasions.

Since the American elements of the Canarian and Madeiran floras
seem as a rule to retain their original generic characters, we may
give third place to the invasion of American plants. They include
Clethra arborea, a beautiful ericaceous tree, the labiate shrubs of
Cedronella and Bystropogon, and species of the umbelliferous genus
Bowlesia, genera that in the aggregate are now most typical of the
warmer latitudes of South America and of the Andine region. The
special difficulties concerned with the origin of these American
elements of the Canarian and Madeiran floras are recognised by both
Hooker and Christ, and both of them find an explanation in the
transatlantic carriage of the seeds of the parent plants. Hooker
wTites that " we can but hazard the assumption that at some very
distant date these genera existed in more eastern parts of South
America, from whence seeds were transported across the ocean "
(Marocco, p. 420). Christ appeals at once to the agency of the Gulf
Stream. However, no evidence of the fitness of these plant genera
for distribution by currents is produced, and I may say here, having
had a long experience of the buoyant capacities of seeds and fruits,
that the future experimenter will most probably find that the agency
of the currents cannot be invoked. It is possible that the problem
may assume quite another complexion, seeing that two of the genera
concerned, Clethra and Cedronella, exist in Eastern Asia, as in Malaya
and Japan. It may be that the American elements of the Macaronesian
floras may require the same general explanation that is apparently
demanded by the almost cosmopolitan connections that linked the
Canaries and Madeira in the earlier stages of their floral history
with the warmer regions of the globe. I refer to the original diffusion
of the same plant-types around the tropics.

However this may be, the Azores w^ere but little affected by the
early invasions of Macaronesia by Asiatic, African, and American
genera. Their floral history begins with the subsequent invasion
of the same region by South European and Mediterranean genera,
that now give character to the Laurel woods of the three Macaronesian
groups. But even this invasion must have taken place at a period
remote from the present. Although there has been no generic
dissociation, several of the trees and shrubs are not to be found
outside Macaronesia, and we should often look in vain in their
original European home for the parent stocks. Yet, as is shown
by Hooker and Christ, " the same plants, or their congeners or
close allies, are found abundantly fossil in the Tertiary strata of

THE AZORES

413

many parts of Europe " (Hooker's Lecture, p. 26). Let me give
an example, which is typical of much. If there is one tree that is
characteristic of these Laurel woods of the Macaronesian islands,
it is Laurus canariensis . Although it is now confined to these islands,
it grew in South Europe in Upper Tertiary times. It was to this
and its associated plants that Hooker was alluding when he wrote
that the vegetation of Europe has undergone a complete revolution
within the lifetime of species that now so forcibly arrest our attention
in the forests of the Canaries, Madeira, and the Azores. These
species, he continues, are living witnesses of that period, when trees,
now characteristic of Asia and America, formed the forests of the
European continents.

The last stage in the history of the indigenous flora of the Macaro-
nesian islands is that represented by species that still exist in Europe
and North Africa. It may be said to be still in progress and includes
the minority of the trees and shrubs of the Laurel woods, and in
the Azores, in particular, the plants of the upland moors.

Presumably, therefore, the Canary Islands and Madeira, especially
the former, hold the wrecks of many floras. To the exclusion of
the Azores, they possess a number of strange genera and peculiar
species, that tells us of the ages which preceded the period indicated
by the non-European trees and shrubs that are common to the
Laurel woods of all three groups. The waves of African, Asiatic,
and American plants that have in successive ages passed over this
portion of the globe, left their wash on the Canarian and Madeiran
groups before the Azorean islands became available for plant-stocking.
Whilst the Azores possess no genus of their own, and relatively
few peculiar species that are beyond suspicion, the Canaries hold
some ten or twelve genera that are all their own, besides a number
of genera, of which they share exclusive possession with Madeira.
It is difficult to separate Madeira from the Canaries in the sense
that we can detach the Azores ; but the contrasts in the floral history
of this region may be sufficiently illustrated by the circumstance,
that, whilst quite one-third of the Canarian species are peculiar,
the proportion amongst the Azorean plants would not exceed a
tenth.

To the student of distribution the Azorean flora offers but few
"problem" plants; whilst the other two groups, particularly the
Canarian, present a host of difficulties of this kind. It is possible
that important episodes in the history of the Azorean flora may have
their only witnesses in Campanula vidalii and Myrsine africana, of
which the first is peculiar to the group, while the second is an Asiatic
and African plant that has been found neither in the Canaries nor
in Madeira. But it would be idle to speculate on their stories now.
I would rather close this chapter with the reflection that whilst in
the Canaries and Madeira quite other questions are often raised
than those concerned with existing means of dispersal, questions
that might carry us far back in geological time, with the Azores
questions dealing with existing modes of dispersal are imminent.
When Wallace expressed the opinion in his Island Life and in his
Darwinism that the plant-stocking of the Azores could be attributed

414 PLANTS, SEEDS, AND CURRENTS

to existing means of dispersal, he was in the main correct, the great
mass of the plants being European species. The characteristic plants
of the Laurel woods, being often peculiar to Macaronesia, do not
come into this category ; but it will be convenient to deal with their
dispersal here. To the subject of the agencies of seed-dispersal
in connection with the Azores, the next chapter will be largely
devoted.

Summary

1. In dealing with the proportion of indigenous Azorean plants,
it is first pointed out that the native flora was in all probability
extremely limited. Although it is likely that the total number of
the alien and native plants would now approach 600, it is held that
whilst the original flora did not comprise 200 species, the plants
that gave character to the vegetation did not amount to 100. Multi-
tudes of plants have been introduced, both intentionally and un-
intentionally, during the period of almost five centuries that has
elapsed since the discovery of the group. Stress is laid on the im-
portance of eliminating the effects of man's agency from every
flora, and it is observed that such an inquiry would be almost as
ruthless in its effects on the British flora as it undoubtedly would
be in the case of the flora of the Azores (pp. 389-91).

2. The original forests of these islands were composed of ever-
green shrubs and trees. Among the trees were Tree-Heaths (Erica),
Laurels (Lauriis and Per sea), Fayas (Myrica), Hollies (Ilex), Tree-
Euphorbias, Junipers, Yews (Taxus), species of Rhavinus, Picconia,
etc. Among the shrubs were species of Daphne, Vaccinium, and
Viburnum (Laurestinus), and Myrsine africana (p. 391).

3. The prevailing impression that the original forests were similar
to the present scrub growth is shown to be an error. There is
abundant evidence that the islands were heavily timbered when
first discovered, and that the destruction of the native woods, with
their large trees, which has been in operation for centuries, has reduced
the woods to their present condition. The process is still actively
continued, and it is evident that for generations the visitor has
formed his impressions of the native trees from " young wood."
The trees attain a respectable size when preserved; but ages of
unhindered gro'v\i:h would be required for the development of the
timber forests that would supply materials, as in the early days,
for erecting churches and building small ships (pp. 392-8).

4. The decrease in size of the timber is well illustrated in the case
of the large size of the original Juniper trees as compared with the
stunted crooked Junipers of our own times. Amongst the trunks
of large trees that have been unearthed from the ashes and other
materials thrown out during the early volcanic eruptions are the
logs of this Juniper, which must have attained in those times the
usual large dimensions of the species (J. oxycedrus). As we learn
from the old writers, the value placed on its timber led to the de-
struction of this fine tree. Although volcanic eruptions must have
played their part in the destruction of the original forests, the agency
of man and animals has been the most effective. As the source of

THE AZORES

415

fuel, land has long been as much valued for the wood that grows upon
it, as for the food raised from it (pp. 393-5).

5. The affinities of the native flora are then discussed, and it is
show^n that the characteristic plants of the woods, the moors, the
ponds and lakes, and the seashore, exhibit a gradually extending
scale of connections with the outer world, the connections being
least with the plants of the woods and greatest with those of the
seashore, the varying degree of isolation thus implied reflecting
the differences in the history of the dispersing agencies. It is pointed
out that this principle is of wide application to insular floras, although,
on account of their lesser antiquity, it has been unable to find its
full expression in the islands of the Azores. Though geographical
isolation often counts for much in the differentiation of oceanic
floras, it is shown that antiquity may largely counteract the effects
of contiguity to a continent. The example is taken of the Canaries,
a group probably far more ancient than that of the Azores. Although
only some fifty miles from the nearest mainland as compared with
800 miles in the case of the Azores, the Canaries hold a flora that
is far more differentiated, the proportion of peculiar species being
at least three times as great (pp. 398-400).

6. After tabulating the distribution of the characteristic plants
of the Azores according to their station, the writer shows how they
illustrate the progressive widening of the connections with the outer
world. With the plants of the woods the most conspicuous features
are these. Whilst mainly non-European, they are largely Canarian
and Madeiran, that is to say, Macaronesian, On the other hand,
the affinities of the plants of the upland moors and of those of the
ponds and lakes are very markedly European, there being no American
connection that is not also European. In the case of the plants
of the seashore, though predominantly European, we get the first
indications of independent and direct connections with the American
side of the Atlantic. Though the affinities of the flora are pre-
eminently European, a possible derivation of European plants by
the way of the mountains of North-west Africa is suggested in some
cases (pp. 400-407).

7. The author then contrasts the zones of vegetation on the great
cone of Pico as representing the Azores, on the Peak of Teneriffe
as representative of the Canaries, and on Madeira. After describing
those of Teneriffe, he discusses the differences that we ought to
expect in the cases of Madeira and the Azores from the differences
in latitude and the associated differences in climate. It is then
inferred that the extensive lower zone (the African zone) of Teneriffe
would be much restricted in Madeira, and absent altogether in the
Azores, whilst the Laurel woods, which have many features in common
in afl three groups and he from 2000 to 2500 feet above the sea
on Teneriffe, would descend to about 1000 feet above the sea in
Madeira, and, when permitted by the cultivator, would descend to
the coast in the Azores. All these predictions are then shown to
be substantially reaUsed, but the reader is referred to the text for
the particulars (pp. 407-10).

8. It is also brought out in this comparison that the Junipers

416 PLANTS, SEEDS, AND CURRENTS

of the upper woods of Pico, which descend to about 2000 feet above
the sea, were originally well represented in the higher levels of Madeira
(probably above 3000 feet), and also on Teneriffe, at elevations
of 5000 to 7000 feet, where they corresponded in their vertical range
with the belt of Pinus canariensis, the pines being unrepresented
either in Madeira or in the Azores (pp. 409-10).

9. A comparison is then made of the summit plants of Pico,
Madeira, and Teneriffe, and it is shown that they have little in common,
those of Pico being derived from the moors below, these upland
moors with their plants being in a general sense unrepresented on
either Madeira or Teneriffe (p. 411).

10. The chapter then closes with a short comparison of the histories
of the plant-stocking of the three Macaronesian groups. Whilst
with the Canaries, and to a less extent with Madeira, there were
early invasions of African, American, and Asiatic plants, they made
but little mark on the Azores. The Azorean flora appears not to
have shared in such revolutionary changes, and its history begins
with the later invasion in Upper Tertiary times from Southern Europe
and the Mediterranean region of plants that in their descendants
now give character to the Laurel woods of all three Macaronesian
groups. The parent stocks have since been driven from their
European home, and the Laurel woods of Macaronesia are all that
remains of a period when trees now characteristic of Asia and America
formed the forests of our continent (Hooker). The last invasion
of Macaronesia, which has extended down to recent times, is indi-
cated by those plants that still exist in South Europe and North
Africa. It is represented by the minority of the plants of the
w^oods, and particularly in the Azores by the plants of the moors
(pp. 411-13).

11. In the case of the Canarian flora, which is made up of the wrecks
of many floras, questions quite other than those concerned with
existing means of dispersal are mainly raised. With the Azorean
flora, however, which has shared only in the later revolutionary
changes of the plant world in this region, the means of dispersal
will figure prominently in any inquiry into its history; and to this
subject the next chapter is largely devoted (pp. 413-14).

CHAPTER XIX

THE AZORES {contiuued)

The Relation between the Differentiating Influences and the Dispersing
Agencies. — Before referring to the modes of dispersal of the plants
of different stations, I will briefly indicate how we may interpret
the relation between the differentiating influences and the dispersing
agencies. Though the specific divergence of most of the plants
of the woods of the Azorean islands indicates a breaking of the link
established by frugivorous birds with their European home, there-
is an important minority, as before remarked, made up of plants
specifically identical with those of Europe, which testify that a
connection has sometimes been maintained down to recent times^
The majority include plants of the genera Hedera, Ilecc, LauruSy,
Myrica, Rhamnus, Smilax, Vaccinium, etc., and the minority com-
prise species of Daphne, Juniperus, Viburnum, etc. But even with
the minority there are signs of the rupture of the connection with
the continent. Thus Juniperus oxycedrus has developed an Azorean
variety (var. brevifolia) which has puzzled the botanist, and Viburnum
tinus has developed an Azorean form (var. subcordata) which according
to Trelease seems to be nearer to a Canarian species than to the
parent species of the neighbouring continent. Looking at these
facts we may regard the connection between the plants of the woods;
of the Azores and those of Europe as either broken or breaking.
But the connection has been kept up with Madeira and the Canaries,
and it would seem that in recent times the activities of frugivorous
birds as dispersing agents have been mainly restricted to the Macaro-
nesian region. It is very different, however, with the plants of the
mountain moors and with the aquatic and subaquatic plants, where
the community with European species leads one to infer that the
connection by birds has been usually continued down to recent times.

The Modes of Dispersal of the Plants of the Azores. — Generally
speaking, the prevailing shrubs, trees, and climbers of the woods are
known to be dispersed, or are regarded as likely to be dispersed, by
frugivorous birds, such as those of the genera Daphne, Hedera, Ilex,
Juniperus, Laurus, Myrica, Rhamnus, Smilax, Taxus, etc. ; whilst
the plants of the dry and wet upland moors of the genera Anagallis,
Calluna, Carex, Hydrocotyle, Menziesia, Polygala, Potentilla, Thymus,
etc., as well as those of the waters and of the borders of ponds of
the genera Callitriche, Littorella, Peplis, Potamogeton, Scirpus, etc.,
possess small and often minute seeds or seed-like fruits, for the
dispersal of which we must look to birds of other habits. The seeds
E E 417

418 PLANTS, SEEDS, AND CURRENTS

of plants of the shores would be distributed directly by currents,
as with Crithmum and Ipomoea, or indirectly in the crevices of drifting
-logs, as with the small-seeded Silene and Spergularia, or by sea-
birds through adhering to their feet and legs, as with Plantago and
J uncus, or carried in their stomachs, as with Polygonum. Very
few of the truly native plants of the Azores are fitted for attachment
by hooks or similar appendages to birds, the Azorean Sanicula
standing very much alone in this respect. It is a genus that has
found its way in this manner to several oceanic islands besides the
Azores, such as Madeira, the Canary Islands, Juan Fernandez,
-Hawaii, etc. The number of small-seeded flowering plants that
jmust be lumped together under the head of those distributed in
mud adhering to birds is large. This " limbo " of the student of
dispersal, to which he assigns a multitude of plants, is not altogether
satisfactory; but for the oceanic island we are left but little choice,
since only the spores of cryptogams, as is shown below, are adapted
for transport by winds over broad tracts of ocean, and not even the
minute seeds of Juncus or the yet smaller seeds of Orchids could
avail themselves of this agency. We come now to deal more in
detail with the modes of dispersal of Azorean plants according to
their stations, and will begin with those of the woods.

1. The Modes of Dispersal of the Plants of the Woods. — As already
observed, most of them would be dispersed by frugivorous birds,
such as pigeons. The specific or varietal differentiation of the
majority of them within the Macaronesian region indicates, as we
have seen, a breaking of the link with their original European home ;
and it is remarkable that this divergence corresponds with sub-
specific differentiation in the Macaronesian islands of the European
wood-pigeon, Columha palumbus, whilst the rock-pigeon, Columba
iivia, has developed an Azorean variety (Hartert and Ogilvie-Grant,
Godman). The Canarian wood-pigeons, as we learn from Lord
Lilford's book on birds (1893, p. 70), and the Azorean pigeons,
according to Drouet, feed largely on the fruits of Persea {Laurus)
indica. Pigeons are credited with a liking for the fruits of other
genera of plants found in the woods of the Azores, such as Ilex and
Hedera. Doubtless the pigeons of Macaronesia are also partial
to the fruits of Myrica faya, the hard stones of which would be
probably ejected unharmed. The other genera of the woods, such
as Daphne, Juniperus, Picconia, Rhamnus, Smilax, Taxus, Vaccinium,
Viburnum, etc., would be distributed by frugivorous birds. It
'may be added that stragglers may have played an important part
in this process, and that we are not restricted in this respect to birds
i:hat regularly visit the islands. In this manner the missel-thrush
^may have introduced the first seeds of the Yew (Taxus baccata) into
'the group, a matter dealt with in the remarks on that plant in a
later page of this chapter.

2. The Modes of Dispersal of the Plants of the Upland Moors. —
Though we have here again to appeal to the bird, the indications
are often largely conjectural. The plants concerned have for the
most part either dry small seed-like fruits or minute seeds. The
following is a series of measurements of some of the seeds stated

THE AZORES

419

in the order of their size — J uncus ^ 0-33 mm. ; Calluna vulgaris,
Menziesia polifolia, Sibthorpia europcea, all 0-5 mm. ; Thymus serpyllum

0- 66 mm.; Anagallis tenella, 0-75 mm.; Lysimachia nemorum, 1-0-

1- 3 mm. ; Luzula, 1-3 mm. ; Potentilla tormentilla, 1-8 mm.

The seeds of Juncus were found by Darwin and others in dried
mud adhering to birds. (I do not find many references to Juncus
in my notes, but species such as bufonius, effusus, capitatus, etc.,
are characteristic of the Azorean flora.) Probably the seeds of plants,
like Anagallis tenella, that grow in boggy ground would be transported
in the same way. But one could scarcely appeal to such an agency
in the case of plants of dry moors, such as Calluna vulgaris and Men-
ziesia polifolia. Yet many birds frequent such moors, even gulls
and curlews in certain seasons, and it is possible that the minute
seeds of Calluna might become entangled in their plumage, when,
as often happens, they make their nests of heather.

Except with Luzula and Juncus, the seeds of but few of the Azorean
moor plants would, according to my observations, emit mucus
when placed in water, or become slimy when moistened, a property
that enables seeds to adhere firmly to plumage on drying. But the
quality is a variable one, even with the same species, as is indicated
by their behaviour in my later experiments in England on the seeds
of Luzula campestris, L. pilosa, and L. sylvatica, and of species of
Juncus, a subject also dealt with in my previous work on the Pacific
Islands (p. 567). It is highly probable that a bird brushing past
such plants in wet weather would carry off on its feathers a number
of the wet seeds of Luzula and Juncus, and that they would adhere
firmly to its plumage when dry. The cause of this tendency to
become slimy and sticky when wetted is described by Buchenau
in the cases of the seeds of Luzula and Juncus in his monograph on
the Juncacece (Pflanzenreich, 1906, pp. 25, 30). It is well exhibited,
he says, in the case of a species of Luzula peculiar to the Canary
Islands. At least five of the nine European species of Juncus
found in the Azores display this property in their seeds, and several
of the species most widely distributed over the world are known to
exhibit it. The aid thus given to dispersal in the case of plants
of many different genera was emphasised in my book on Plant
Dispersal (p. 567); but it had long before been recognised by Kerner
and others, and Buchenau also lays stress on the part which animals
would thus play in the distribution of species of Luzula and Juncus.
As they brush past the plants in wet autumn weather they would
carry away either on their fur or on their plumage the sticky seeds
from the open capsules.

Yet we are in the case of these small-seeded plants often brought
into contact with problems that raise other questions than those of
modes of dispersal. Let us take the three plants with seeds half
a millimetre in size, Calluna vulgaris, Menziesia polifolia, and
Sibthorpia europcea. Calluna has a solitary species which is mainly
European, though it has obtained a hold on the Atlantic side of North
America. Menziesia has half a dozen species found in Europe,
Asia, and North America, but although one at least is common to
the eastern and western hemispheres, M. polifolia is confined to

420 PLANTS, SEEDS, AND CURRENTS

Western Europe and the Azores. Sibihorpia holds a similar number
of species which live in the Andes, in the mountains of Mexico, in
Europe, in Africa, and in Nepaul. The Canary group has its own
species, and Sibthorpia europcea not only extends to the Azores,
but is found in the mountains of the Cameroons and in the Abyssinian
Alps.

3. The Modes of Dispersal of the Aquatic and Subaquatic Plants. —
It may be observ^ed that in most cases these Azorean plants possess
minute seeds or very small seed-like fruits, such as we find in Peplis
portula, Littorella lacustris, Callitriche aquatica, and Scirpus fiuitans,
which could have been transported to the group in mud adhering
to birds. The small fruits of the common Potamogeton {P. poly-
gonifolius) are 2-3 mm. in size and float in quantities on the surface
of the ponds and lakes in the latter part of the summer. They
would be readily swallowed by wild ducks and other waterfowl,
and I have sho^\^l in my book on Plant Dispersal (pp. 369, 513), not
only that the fruits of Potamogetons are to be found in the stomachs
of these birds, but that they germinate much more readily after
passing through a bird's digestive canal. This Potamogeton figures
on the island of Pico as an aggressive species that is gradually taking
possession of the mountain lakes and ponds and is ousting such
plants as Littorella lacustris and Isoetes lacustris {I. azorica, D.)
from the shallows. Doubtless it is a more recent arrival than the
two species just mentioned. As to the spores of Isoetes it may be
remarked that they were most probably brought in dried mud adhering
to the feet of birds of aquatic habits. The seed-like fruits of the
cyperaceous species that line the water's edge, Carex flava, Scirpus
multicaulis, S. palustris, etc., were, it is likely, originally transported
in the stomachs of w^aterfowl. Wild ducks, as has been shown
in the work above quoted (p. 513), swallow the hard nutlets of
Cyperacece in quantities, and these fruits readily germinate after
being removed from the stomach and intestines. The fruits of
Scirpus palustris sink, but those of Carex flaia buoyed up by the
utricle float for six months and more, and form a constituent of the
floating drift of ponds.

4. The Modes of Dispersal of the Coast Plants. — The littoral flora
of the Azores is scanty owing to the coast being usually rock-bound.
We might have expected as in tropical regions that the currents
would have been important agents in stocking these shores with
their plants, but, unless we include the intermediate agency of the
drifting log, they have not taken a prominent part. In this respect
the littoral flora of the Azores behaves like the shore floras of temper-
ate latitudes (see Plant Dispersal, p. 33). The foHowing are the
results of the ^Titer's observations on the capacity of the seeds or
fruits for direct transport by currents.

When the data are supplied by old experiments and observations
to be found recorded in the writer's previous book on Plant Dispersal
they are marked O.

Beta maritima. — The nutlets sink in sea-water, but enclosed in
the perianth, whether fresh or dry, they may float for two or three
days (O).

THE AZORES

421

Cdkile edentula. — The upper joints of the fruits float for nine
or ten days. Probably introduced in ballast from America (see p. 189).

Crithmum maritimum. — The original flotation experiments in
sea-water covered ten months, 95 per cent, of the carpels remaining
afloat (O). They were subsequently extended to thirteen months,
when 90 per cent, remained afloat, a few of which germinated in
soil two months later.

Euphorbia azorica. — The seeds float in sea-water from one to two
weeks, but the water soon penetrates their coats. In the case
of E. peplis he has no data; but the floating powers are probably
limited.

Hyoscyamus albus. — The seeds sink.

Ipomcea carnosa. — The seeds float unharmed in sea- water for twelve
months and more and germinate afterwards (see p. 218).
Juncus acutus. — The seeds sink.
Plantago coronopus. — The seeds sink.

Polygonum maritimum. — The nutlets sink in sea-water, but en-
closed in the perianth they float three or four days. The entire
plant, or branches of it, would float five or six days when carried off
a beach by the waves (O).

Salsola kali. — Enclosed in the perianth the fruit floats in sea- water
for a few days, but when detached it sinks. Portions of the plant
bearing mature fruits float at first, but sink within ten days (O).

Samolus valerandi. — The seeds sink (O).

Silene maritima. — Seeds sink (O).

Solidago sempervirens. — No data, but prolonged buoyancy is
unlikely.

Spergularia marina. — Seeds sink (O).

Of the fifteen shore plants above named only two, Crithmum
maritimum and Ipomcea carnosa, can be regarded as adapted for
transport by currents to the Azores. Nearly half of them have
small seeds, namely, the species of Hyoscyamus, Ju7icus, Plantago,
Samolus, Silene, and Spergularia. It is not unlikely that the seeds
of the Hyoscyamus, Silene, and Spergularia, are carried in the crevices
of drifting logs. But sea-birds are also able to assist in the distri-
bution of these small seeds. Gulls, for instance, often make their
nests on the faces of cliffs in the midst of a dense growth of Sea-
Campion (Silene maritima) ; and it would be surprising if they did
not aid in the distribution of this plant. Still more likely would
this be with Plantago coronopus, which grows on the rock-ledges
where these sea-birds nest. Here the seeds emit mucus and become
sticky when wetted, and they would adhere firmly to a bird's plu-
mage when dry. The small seeds of Samolus valerandi have been
found in mud adherent to birds; and the frequent growth of the
plant in wet places by the sea would afford opportunities of this
occurring (Kerner). The prickly pointed leaves of Salsola kali would
enable bits of the plant carrying fruits to catch in feathers as readily
as they do in one's clothes. Many granivorous birds are fond of
Polygonum nutlets, which are often found entire in their stomachs ;
and doubtless birds frequenting beaches would swallow the seeds

422 PLANTS, SEEDS, AND CURRENTS

of Polygonum maritimum. The seeds of J uncus acutus, like those
of other species of the genus referred to on a previous page, would
probably become sticky when wet, and would thus adhere firmly
to a bird's plumage.

The Efficacy of the Wind in the Oversea Dispersal of Seeds. — Much
has been written, but few actual facts have been recorded relating
to this subject. Mr. Wallace in his Darwinism (1889) made a
strenuous appeal for the paramount influence of \™ds over birds
in transporting small seeds like those of Sagina and Orchis over tracts
of ocean 1000 miles in width. " For each single seed carried away
by external attachment to the feet or feathers of a bird, countless
millions (he says) are probably carried away by violent ^\inds; and
the chance of conveyance to a great distance and in a definite direction
must be many times greater by the latter mode than by the former "
(p. 373). He based his opinion upon the careful comparison of the
size of a number of small seeds with those of quartz grains, -^^th of
an inch across, found in deep-sea deposits 700 miles from land and
regarded by Sir John Murray as distributed by the winds.

There seems to be no question about the fitness of cryptogamic
spores for dispersion by mnds across broad tracts of sea. It is
concerning the seeds of flowering plants that doubts would be raised.
The great contrast in weight between the lightest of small seeds, as
in those of orchids, and the average weight of a mushroom spore
(orchids, 8000-15,000 seeds to a grain, Wallace and Kerner; mush-
room spores, probably some hundreds of thousands to a grain) at
once indicates problems of a very different nature. With regard
to species of flowering plants represented in the Azores, the following
measurements of size and weight were obtained by the author w4th
the exception of those for Sagina procumbens which are supplied by
Wallace in the work above named.

Sagina procumbens, -^hj of an inch, ^^^00 ^ grain.
J uncus communis, ,, ,, -5W0

Erica azonca, ^ „ „

Calluna vulgaris, „ „

Sibthorpia europcea, -^^ ,, ,, two

Menziesia polifolia, ,, ,, ttu-q

Thymus serpyllum, ^ „ „ ^

Lysimachia nemorum, ,, ,,

Cotyledon umbilicus, -7^

5

Note. — The relation between size and weight varies with the form
of the seed. Thus the rounded seeds of Thymus are much heavier
for their size than the oblong somewhat flattened seeds of Calluna.

Yet minute as the seeds of many widely distributed flowering
plants may be, Wallace gave no weight to a very important factor
in the continuous action of gravity, which seems to nullify any fitness
such seeds might appear to possess for transport by the wands across
a broad tract of ocean. All that follows, relating to this factor,
is based either directly or indirectly on materials supplied by Mr.

THE AZORES

423

Lloyd Pracger in his botanical memoir published in the reports of
the Clare Island Survey in 1911 (Proc. Roy. Irish Acad.). The appli-
cation of his data to the Azorean flora is my own, and possibly the
author may pardon me for making such a free use of his work ; but
it will best express the measure of my indebtedness.

The contrast in weight between the smallest seeds of flowering
plants and the spores of cryptogams, reflects the difference between
inefficient and efficient dispersal by winds over great distances.
Mere reduction in size, writes Lloyd Praeger (p. 79), is not carried
far enough in the flowering plants to produce efficient dispersal by
winds. With their seeds we can detect a certain amount of relation
in their responses to the action of gravity between their size and
falling rates ; but quite another order of things presents itself in the
case' of cryptogamic spores. Small and light as it is, the seed of an
orchid falls through the air at least fifty times as fast as the spore
of an ordinary mushroom. Here I have taken the average terminal
velocity of an orchid seed at one foot per second and of a mushroom
spore at 6 mm. a second. It will be seen below that according
to the data given in Prof. Buffer's British Association paper (1909,
p. 675) the average falling rate for hymenomycetous spores would
probably be much less; but in order not to overstate the contrast
the most rapid rate has been chosen. This comparison will serve
to illustrate the remark in Lloyd Praeger's paper (p. 70) that the
behaviour of small particles falling in air differs from that of larger
bodies, inasmuch as with continual reduction in size the impelling
force of gravity becomes rapidly smaller in comparison with the
decrease of resistance offered by the air, so that very small velocities
result.

At the close of Chapter XVI. this matter is briefly mentioned in
connection with the Peat-mosses. Here it is treated more at length
with reference to the Azorean flora. It would appear from the
numerous experiments of Lloyd Praeger on the falling rate of seeds,
using the term " seed " in a general sense as implying in the words
of this writer the unit of dispersal, that except in the case of plumed
seeds of the lightest weights, such as those of Typha and Epilobivm,
we could not appeal to the winds for the transport of even the smallest
seeds of flowering plants, this agency being only available for the
spores of cryptogams.

To postulate the effects of gravity, as indicated by the falling
rate of seeds and spores, an initial altitude at the starting-place must
be assumed. If the wind has been effective in stocking the Azores
with plants we must regard Southern Europe as the starting-place,
since that is the source of the great majority of the small-seeded
flowering plants. Taking the distance of this group from the nearest
coasts of Portugal at about 800 miles, I have below given the minimum
initial elevation that would be required for seeds and spores to reach
the Azores with a favourable wind blowing with the force of a strong
gale at fifty miles an hour. The falling rates of the spores are taken
from some of the results obtained by Prof. Zeleny and Mr.
McKeehan, as well as by Prof. Buffer, which are given in the
British Association Report for 1909 (pp. 408, 675) and in Nature

424 PLANTS, SEEDS, AND CURRENTS

for October 14, 1909, those for the seeds being supplied by Mr.
Lloyd Praeger's report in the Clare Island Survey (Proc. Roy. Irish
Acad., XXXI., 1911). All the plants indicated under the various
headings are with the exception of Typha latifolia represented in
the present flora of the Azores.

Tablb illttstbating the Falling Rates of Spores and Seeds and the Initial
Elevatiok that they woitld require if transported by the Wind from
THE Uplands of Portugal to the Azores, a Distance of about 800 Meles.
(Seb above for explanatory remarks.)

Falling Rate.

Minimum Initial Elevation with
favoiirable wind blowing fifty
miles an liour. (Elevations
approximate.)

Hymenomycetes (mush-
rooms in a general
sense).

0'3 to 6 mm. per second
(B.).

57 to 1130 feet.

Lycoperdon (puS-ball).

0*46 mm. per second
(Z. and M.).

86 feet.

Polytrichum.

2'28 mm. per second
(Z. and M.).

430 feet.

Lycopodium.

Ill mm. per second
(Z. and 31.).

3300 feet.

Typha latifolia (plumed
seed).

12 feet in 34 seconds.

20,000 feet or 3^ miles.

Epilobium (plumed seed).

12 feet in 20 seconds.

35,000 feet or 5| miles.

Sonchus oleraceus,
Senecio vulgaris
(both plumed seeds).

12 feet in 12-7 and 12-8

seconds.

54,000 feet or nearly 9
miles.

Habenaria (orchid).

12 feet in 12 seconds.

58,000 feet or 9J miles.

Carduus pycnocephalus
(plumed seed).

12 feet in 5 seconds.

138,000 feet or 22^ miles.

Sagina procumbens.

: 12 feet in 3*5 seconds.

197,000 feet or 32 miles.

Juncus.

12 feet in 3 seconds.

230,000 feet or 38 mUes.

We may infer from the data just given, assuming that the argument
is valid, that whilst there would be no difficulty in postulating the
requisite initial uplift for cryptogamic spores we could not do so
for the seeds of Juncus and Sagina yrocumhens, however small they
may be. But the difficulty is not so great as it at first seems for those
seeds that require an initial elevation of from six to ten miles, as
in the case of Epilobium, Senecio, Sonchus, and Habenaria, Typha
being excluded as it is not found in the Azores. If the wind blew
with the extreme maximum force of a hurricane, say, at 100 miles
an hour, the lift requisite for the seeds would be halved and the
passage to the islands would be accomplished in eight hours. Under

THE AZORES

425

such conditions Epilobium would only require an initial elevation
of about 17,500 feet. Senecio vulgaris and Sonchus oleraceus would
require about 27,000 feet, and Hahenaria about 29,000 feet. I am
not assuming that any of these flowering plants were introduced
into the Azores by the winds. In fact, there is good reason for
holding that in the case of the plants with plumed seeds they were
introduced as weeds. But it is quite possible that Epilobium seeds
might be carried across a tract of ocean, a few hundred miles broad,
if they began the passage high up a mountain's side.

The up-draught that occurs on the slopes of lofty mountains
would soon carry the spores of cryptogams to levels several thousands
of feet above the sea. These ascending currents, according to
Whymper, Humboldt, and others, transport insects up to levels
of from 15,000 to 19,000 feet on the Andes, and, as the writer himself
observed, to the summit of Mauna Loa in Hawaii, about 13,600 feet
above the sea (Plant Dispersal, p. 585). As discussed in the work
just quoted, they form an important factor in the climatic regime
of mountain regions, and as such they are treated by Samler Brown
in the case of the Peak of Teneriffe in his Guide to the Canary Islands
(1905, pp. 624-^29).

The most pertinent example of oversea transport of seeds by the
winds that can be quoted in this connection is that given by Warming
in his writings on Greenland and the Faroe Islands, and referred to
by Sernander in his work on Scandinavian vegetation. Here large
quantities of plant debris, mostly fruits of Calluna vulgaris mixed
with blossoms of Erica tetralix, were, during a gale in February 1881,
blown across the Cattegat from the Swedish coast to the eastern
shores of Jutland, a distance of 110-120 kilometres. But if we wish
to believe that the islands of the Azores were originally stocked with
Calluna vulgaris in this manner, we are concerned with transport
over a tract of ocean thirteen times as broad as the Cattegat. It
is not possible to deal further with these matters here, and the reader
may be referred for a general discussion of the subject of the wind
as a transporting agency to Lloyd Praeger's pages and to Ernst's
New Flora of Krakatau.

Notes on the Plants of the Azores

These notes may be prefaced with the remark that there is in
general a close agreement between the ranges of the altitudes obtained
by myself on Pico and those ascertained for the same mountain by
Hochstetter, with whose work I was at that time quite unacquainted.
Watson (p. 114) writes in a depreciatory tone of the " alleged ranges
of altitudes " given in Seubert's Flora, and ignores them altogether.
They were all derived from Hochstetter, and are in my opinion
generally to be relied on. They are often given in the following
notes, some of them being taken from the paper by Seubert and
Hochstetter in Wiegmann's Archiv.

Acrostickum squamosum, Sw. — Grows on Pico at altitudes of 2000
to 5000 feet. Hochstetter, 2500 to 5000 feet.

Anagallis tenella, L. — It is singular that a plant so abundant

426 PLANTS, SEEDS, AND CURRENTS

in the wet moors of the uplands of the island of Pico, should, as far
as its previous identification by Drouet is concerned, have been
regarded with a little suspicion by Watson (p. 213). With Arceutho-
hium oxycedri and Hydrocotyle vulgaris it escaped the notice of the
Hochstetters. Drouet recorded it from Pico and Santa Maria.
Trelease found it on Flores, and it can scarcely be doubted that it
will prove to be abundant on San Jorge. It flowers abundantly
in July, and grows at altitudes of 2000 to 4000 feet. The results of
my observations on a peculiar habit of gro^\i:h of the plant in England
are given in Note 24 of the Appendix.

Arceuthohium oxycedri, M.B. — The name of this genus is a compound
of two Greek words, and signifies " living on the Juniper," Juniperus
oxycedrus serving as the host for this parasite in South Europe.
The writer was the first to record this plant from the Azores. It
first came under his notice in March 1913, growing plentifully upon
the trunks and branches of the Junipers (J. oxycedrus, var. brevifolia)
on the Bandeiras or north-west slopes of the great mountain of Pico
at altitudes of 2500 to 2800 feet, its brownish-yellow or gamboge hue
making it a striking object on the dark-coloured trees. During this
season it did not come under my notice on the southern slopes of
the mountain ; and had it not been for a chance ascent above Ban-
deiras I should have left Pico, like the Hochstetters, without being
aware of its existence. On sending the specimens to Kew, the
Assistant-Director, Mr. A. W. Hill, wTote to me saying : " We are very
interested in your discovery on the slopes of Pico. The parasite
proves to be Arceuthohium oxycedri, M. Bieb. We have no specimen
of this from the Azores, nor can we find any record of its having
been found there previously." In the summer of the following year
I came upon it growing frequently on the Junipers at elevations
of 3000 to 4000 feet on the south-east and east slopes of the mountain.
It also came under my notice off the mountain, growing on the
Junipers in the vicinity of the Lagoa das Teixas which is situated
at an altitude of 2500 feet at the back of San Roque. Here its growth
was more luxuriant than on the cone.

The species has a wide distribution in South Europe, and, as in
the Index Kewensis, is generally credited also to North America;
but Mr. Hemsley in a letter to me wTites that it would be worth while
looking into the question of the specific identity of the North American
plant commonly referred to Oxycedri. Ten species are enumerated
in the Index Kewensis, of which eight are confined to North America
and one to the Himalayas, whilst the species under consideration
is the only one common to Europe and North America. Sir D.
Brandis in his Indian Trees states that A. oxycedri grows in the Hima-
layan region on Juniperus macropoda at elevations of 9000 to 11,000
feet. According to Arcangeli's Flora Italiana, Arceuthohium
oxycedri ranges in South Europe from Spain to Servia, and occurs
also in North Africa, the Taurus, and Persia. Harshberger, in his
work on the Phytogeography of North America (pp. 555, 556, 608),
mentions three species, all growing on Pines, one in the Southern
Rocky Mountains at elevations of 8000 to 10,500 feet, and the two
others in the Colorado and Californian regions. Urban (VII., 205)

THE AZORES

427

describes a new species from an altitude of 4000 feet in the mountains
of San Dominf]fo in the West Indies.

The mode of dispersal of the genus Arceuthohium is illustrated in
the cases of A. oxycedri and A. occidentale as described by T. Johnson
and G. J. Peirce in the Annals of Botany (Vols. II. 1888, XIX. 1905),
The seeds are discharged explosively," and are about a millimetre
in size. Their flight may cover a distance of fifteen to twenty feet,
and on account of their viscid exterior they adhere firmly to sub-
stances, the attachment holding for many months or even for a
year. It is thus likely that birds actively disseminate the species,
carrying the seeds firmly adhering to their plumage. In this respect
Arceuthohium resembles Luzula, which is mentioned in this connection
in an earlier page of this chapter, and it is noteworthy that the two
genera have a similar distribution.

Cakile edentula. Big. — See p. 384.

Calluna vulgaris, S. — Begins to flower at the end of July. Grows
at all elevations on Pico from the coast to the top of the peak.

Campanula vidalii, W. — This plant is peculiar to the Azores. It
was first gathered by Captain Vidal in 1842 from " an insulated
rock " off the coast of Flores. Watson subsequently made an un-
successful search for it on the main island (p. 188). Afterwards
(1844-48) Mr. Carew Hunt found it " very locally on the coasts of
San Miguel and Santa Maria," and it was from one of these islands
that it was introduced into English gardens (Ibid.). It is one of
the most beautiful plants of the Azores, is stout and shrub-like,
attains a height of two feet, and has milk-white flowers, one to one-
and-a-half inches long, the corolla being constricted in the middle.
Trelease, who visited the group in 1894 and 1896, speaks of it as then
occurring " on cliffs and detritus by the seashore and on outlying
rocks around the entire island of Flores " (p. 128). He alludes to
the impression in the islands that it occurs in cultivation only outside
Flores and was originally derived from that island. However, in
1909 Druce found it on the cliff-side at Capellas on the north-west
coast of San Miguel {Journal of Botany, 1911), and the present writer
came upon it there on the same cliff-side in 1913. As regards its
habitats in the group, it should be borne in mind that when it was
first collected by Captain Vidal amd Mr. Carew Hunt, 1842-48, the
islands of San Miguel and Santa Maria were as much entitled as that
of Flores to be considered the proper habitats of the species, since
in all three cases the indications went to show that it was a scarce
coast plant. Where observed by Mr. Druce and myself on the cliffs
of San Miguel it was growing in its natural station. Both Dr.
Carreiro and himself regarded it as truly indigenous in that locality.
It did not come under my notice on Pico, but it may grow on San
Jorge, and I am inclined to consider that it was originally widely
distributed over the Azores and is on the road to extermination.
It seeds profusely and germination takes place readily as the
seeds lie on the soil. Like Watson, I raised plants in my garden
from Azores seeds ; but on the coast of South Devon they are much
injured by the severer frosts when kept out of doors during the
winter, but few surviving.

428 PLANTS, SEEDS, AND CURRENTS

Questions of modes of dispersal seem hardly pertinent in the case
of a plant that like this species is restricted to a single group of
islands. The seeds are smooth, 0-75 mm. long, and they sink in
sea-water. They appear as well fitted for wide dispersal as those
of a multitude of small-seeded plants with great ranges. The history
of this species probably carries us back to an early stage in the plant-
stocking of the Azores. Watson writes (p. 189) that each group of
Atlantic islands (Azores, Madeira, Canaries, Cape Verdes) has its
peculiar Campanula, the Madeiran and Canarian plants affording
technical characters for generic distinction, whilst that of the Azores
is " a true Campanula, though with the habit of a shrubby Semper-
vivum,'' A clue to the parentage of the Azorean species may perhaps
be found in the form of the first leaves. Whilst the typical leaves
are long, lanceolate-spathulate, and serrate, the cotyledons are entire,
broad, and almost deltoid. The first leaf is similarly broad,
but subcordate at the base, and fringed with long hyaline
hairs. The serrations begin to develop in the second leaf, which
is ovate in form. The transparent hairs disappear after the fourth
leaf, which is broadly oval and deeply notched. The succeeding
leaves rapidly assume the characteristic lanceolate-spathulate form
which is acquired in the sixth or seventh leaf.

Daphne laureola, L. — The " Trovisco " of the Azoreans. Only
recorded from Pico. Though Seubert, whose notes were supplied
by the Hochstetters (1838), mentions no other island, Drouet who
visited the group in 1857 was assured that there was formerly much
of it in the valley of Furnas, San Miguel. It is highly probable
that it grows on San Jorge. I found it in flower-bud in the end of
March and beginning of April 1913, and in early green fruit in the
first half of July 1914. Evidently it flowers in May. Grows on
Pico at levels between 3000 and 5000 feet. According to Hochstetter
it is found at elevations of 3000 to 4000 feet. Watson observed it
" probably between 4000 and 5000 feet " {Lond. Journ. Bot, 1843).

Dicksonia culcita, Herit. — On Pico it grows at altitudes of 2000
to 4500 feet. Hochstetter places it in the zone of the upper mountain
woods, 2500 to 4500 feet. In San Miguel it reaches the tops of two of
the principal mountains, Pico da Vara, 3570 feet, the highest peak
in the island, and Agua de Pao, 3070 feet.

Erica azorica, Hochst. — Flowers in May and June. When men
or cattle brush against the branches in June dense clouds of pollen
are given off. Fruits in July and August. Ranges in altitude on
Pico from the coast to 6000 feet, but it is much dwarfed in the higher
levels^ namely, above 4500 feet. Seubert, quoting Hochstetter,
states that it ascends this mountain to above 6000 feet.

Euphorbia azorica, Hochst. — Commencing to flower in the middle
of March 1913.

Euphorbia mellifera, Ait. (= E. stygiana). — Recorded from all
islands except Graciosa, San Jorge, Terceira, and Santa Maria, but
doubtless it exists or did exist there. According to Seubert it grows
in the mountain ravines of Fayal and Flores at elevations of 2000
to 3000 feet. On Pico it grows usually between 3000 and 4000 feet.
Often grows sporadically, when it may attain a height of eleven or

THE AZORES

429

twelve feet; but sometimes gregariously, when it is usually three
to six feet high and may form thicket-like growths.

Iledera canariensis, W. — Fruits in winter as with our English
speeies. Observed in mature black fruit in February and up to the
end of March. The fruits had all fallen by the end of June. Evi-
dently, therefore, as with our Ivy, they fall in April and May. On
Pico it may reach as high as 3500 feet, but it is most characteristic
of the Faya zone, that is, below 2500 feet.

Hypericum foliosum, Ait. — Flowers in June and July. The
empty fruits remain on the plant during the winter and spring.
Plants in full bloom in June may still carry the old fruits of
the previous year. Typical of the lower woods, that is, below
2000 feet.

Hydrocotyle vulgaris, L. — First recorded from the group by Trelease
from Flores in 1894. I found it in 1914 to be one of the most abun-
dant plants on the moist upland moors of Pico, 2000 to 4000 feet above
the sea. Doubtless it also grows on San Jorge.

Ilex per ado, Ait. — The Azevinho" of the Azoreans ; but the word
is so clipped that it sounds like " Azvi." The time of flowering
depends on the altitude. Thus in the lower levels this usually occurs
in April and May, as in Madeira (Lowe) ; but in the high levels in
June and July. According to Seubert it is in flower in the mountains
in June when it is in mature fruit in the gardens. However, on
Pico it was frequently to be observed bearing ripe red fruit at the
latter end of March, and on one occasion I found the same tree in
early flower and mature fruit. It is equally characteristic of the
upper and lower wood zones of Pico between 1000 and 5000 feet.
According to Seubert and Hochstetter it grows in the higher levels
of all the islands, and on Pico at 4000 to 5000 feet. The genus,
though so widely distributed over the world, seems rarely to occur
in oceanic islands. It would appear that the distribution of the
primitive family type over the Pacific took places ages since, and
that with the breaking up of the connections through the failure
of the dispersing agencies differentiation has been induced. Thus,
although no species of Ilex is known from the islands of the tropical
Pacific, they possess in Byronia another genus of the family which
they share exclusively with Australia, Hawaii holding one species,
Tahiti another, whilst Australia claims a third.

Ipomoea carnosa, R. Br. — See p. 218.

Isoetes azorica, D. — This species was first catalogued by Watson
as /. lacustris. Since the genus was once regarded as monotypic
and later as holding a few species, whilst at the present it is credited
with more than fifty species, there is room for the view that the
larger conception of the specific value may be the most correct.
The plant was first found by Watson on Corvo in 1842. After more
than half a century (1894-6) it was rediscovered there by Trelease,
whilst his son found it on Flores. The present writer discovered
it in the lake district of Pico in 1914. In all probabihty it grows
on San Jorge. That curious association of Isoetes with Littorella
at the borders of a pond or lake, which has so often been remarked
in other parts of the world, is to be observed on Pico. There are

430 PLANTS, SEEDS, AND CURRENTS

some points of resemblance between two types of plant life, otherwise
so widely divergent from each other, notably the similarity in general
appearance between the aquatic long-leaved forms. From the
standpoint of dispersal one inference seems permissible, namely,
that the two plants reached the Azores in a similar manner. From
this arises the implication that the Isoetes spores were not brought by
the winds, but, like the small seed-like fruits of Littorella, in mud
adhering to aquatic fowl.

Juniperus oiycedrus (var. brevifoUa, Hochst.). — The " Cedro "
of the islanders. We learn from Seubert and Drouet that this tree
was especially frequent on Flores where the largest individuals
occurred. It would seem that it matures its fruit in the autumn.
But the data at my disposal do not decide this point. Aiton in his
Hortus Kewensis speaks of J. oxycedrus as " the bro-sMi-berried
Juniper,'' and this name would apply also to the Azorean variety,
the ripe fruits rarely colouring and then only to a slight extent. On
Pico in March, June, and July, full-sized fruits were often abundant.
On the higher slopes of Pico da Vara (San Miguel) fruits were scanty
on February 23. Evidently the fruits often remain on the trees
during the -winter, probably those that fail to mature by the autumn.
In this respect one may note that Sernander (pp. 321, 328, etc.)
places Juniperus communis amongst the numerous Scandinavian
plants that are most actively dispersed in the winter on account of
the fruits remaining on the tree. Strange to say, the greatest display
of fruit in the case of the Azorean Jmiiper was exhibited on April 1
on the snow-covered upper slopes of Pico at an altitude of 5200 feet.
Two old trees, about ten feet high and standing all alone, were
simply laden with full-sized fruit carrying mature seeds and in some
cases slightly coloured.

The vertical range of the Azorean Juniper on the slopes of Pico
was placed by the Hochstetters at 2500 to 5000 feet. This fairly
represents the usual limits. But in the dwarfed semi-prostrate
condition I found it scrambling up the lava slopes on the eastern
side to nearly 6000 feet ; whilst it would be more correct to place the
lower average limit at 2000 feet, though it may occur sporadically
as low as 1200 or 1300 feet. Off the mountain the Juniper is
most at home in the lake district of Pico. There, at altitudes
of 2500 or 2600 feet, it attains a greater size and exists in larger
quantity than on the slopes of the cone where it is to be found best
represented in the upper woods of the eastern slopes about 4000
feet up.

There has been much discussion as to the relation of the Azorean
Juniper to Juniperus oxycedrus of South Europe. But Seubert
and Hochstetter designated it as a variety of the European species
under the name of " brevifolia." There seems a great deal to support
the view of Seubert that it stands to J. oxycedrus as J. nana does
to J. communis. Let us take the case of the last named. Scott
Elliot in Botany of To-day (1910, p. 94), wTites as follows in this
connection. " In the lowland districts this is a large shrub or small
tree, which is occasionally thirty feet high. But in the mountains
it becomes a dwarf form (J. na?ia), which is seldom one foot high.

THE AZORES

431

If one cultivates J. nana in the lowlands, as has been done both in
the Berlin and in the Zurich botanical gardens, it changes into
Juniperus communis. This has been tried both with seeds and by
transplanting a mature specimen (Kirchner)." Baron von Mueller
in his Select Extra-Tropical Plants (p. 170) writes that under favour-
able circumstances J. communis may attain a height of nearly fifty
feet.

The behaviour of J, oxycedrus is much the same. In South Europe
it rarely exceeds the dimensions of a bush, five or six feet high.
Yet Hooker in his book on Marocco (p. 252) refers to the occurrence
at an altitude of about 3500 feet on the slopes of the Great Atlas
of "an old weather-beaten trunk measuring about five and a half
feet in circumference and seemingly of high antiquity." In Madeira,
as we are told by Mr. J. Y. Johnson (Encycl. Brit. 9th edit., XV., 180),
J. oxycedrus was formerly abundant and grew to a height of forty
or fifty feet. It is, therefore, highly probable that under the favour-
able conditions for forest growth which evidently prevailed in the
Azores at the time of their discovery, the present Juniper trees, which
do not usually exceed ten or eleven feet high, may have attained
the great dimensions attributed in the pages of the historians of
the group to the " cedros " of the original forests.

But the points we are most concerned with here are the shortening
of the leaves in the present Azorean Junipers and the validity of
regarding this feature as a specific distinction. The matter is thus
stated by Watson (p. 224) : " The leaves (of the Azorean plants)
are wide and blunt in comparison with those of the South European
Oxycedrus^ and only half their length." From somewhat limited
materials at his disposal he formed the opinion that the Azorean
Juniper seems a wider divergence from the European Oxycedrus
than are the Junipers of Madeira and the Canaries, the transition,
however, being slight from the Azorean to the Madeiran form and
from this again to the Canarian form. However, it stands as a peculiar
Azorean species in the Index Kewensis, and Prof. Parlatore takes
the same view in De Candolle's Prodromus. The same view is
taken, according to Trelease, by Antoine in his Kupressineengattungen.

I will now give my own observations. On Pico I found that
there were two forms of the plant connected by intermediate stages,
the one with short obtusely pointed leaves tending to lie close to
the stem, and near the " brevifolia " type, the other with long almost
linear acutely pointed leaves tending to spread away from the stem,
and near the " oxycedrus " type. As regards the position and relative
length and breadth of the leaves these are also the characters, as
indicated by a figure after Warming given in Schimper's Plant
Geography (p. 36), which distinguish J. nana from the ordinary
type of J. communis.

On the wind-swept upper slopes of Pico da Vara in San Miguel,
where the plants are much dwarfed, I found the short-leaved type
prevailing. In the Carreiro herbarium in the Municipal Library
at Ponta Delgada there are short-leaved specimens from Pico de
Vara and long-leaved specimens from Siete Cidades. On the slopes
of Pico I often found the two forms associated in the same locality

432

PLANTS, SEEDS, AND CURRENTS

together vriih the intermediate forms. Subjoined are some measure-
ments of leaves made on dried specimens.

Long-leaved form from Pico, length and breadth of leaf, 9-9-5 x 1 -5 mm.
Intermediate „ „ „ „ 7*5x2 „

Short-leaved „ „ „ „ 5-5x2

Short-leaved ,, Pico da Vara, San Miguel 5*5-6 x 2

Schimper (Ibid.) refers to Warming's view that the tendency of the
leaves of the form nafia of J. communis to be appressed to the stem
as compared with those of the common form, where they stand apart
from it, illustrates a method of protection against transpiration.
My data indicate that the appression and shortening of the leaves
is most characteristic in the Azores of the dwarfed plants on ^^^nd-
swept mountains. The most typical forms of the long-leaved or
Oiycedrus type on Pico grew in relatively sheltered situations,
whilst the plants found in exposed localities at altitudes of 5000
feet and over belonged for the most part to the intermediate and
short-leaved types. Vie^ving the " brevifolia " variety as an adapta-
tion to the inclement climatic conditions of the higher levels of the
Azores, it is quite likely that the typical long-leaved, or Oxycedrus
type, largely disappeared \s4th the destruction of the timber forests
that originally clothed the lower slopes of the islands.

Laurus canariensis, Webb (= Persea azorica, Seubert). — The
" Louro " or " Loro " of the Azoreans and Canarians. Flowers
profusely in the Azores. According to the observations of the Hoch-
stetters and of Drouet it is in full bloom in May, but, as I found on
Pico and San Miguel, in 1913, the process may begin in March. It
is in green fruit in July, and probably matures its fruit in August.
The Hochstetters restrict it to the lower mountain woods of Pico
between 1000 and 2500 feet ; but I found it to be also abundant
in the upper mountain woods, which extend to 4500 feet. Its usual
range on Pico is 1000 to 4000 feet, but it may extend to nearly 5000
feet. In the upper levels it is much dwarfed, the tree attaining its
greatest size in the lower levels (1000 to 2000 feet). On San Miguel
it occurs as a stunted gro^\i:h at an elevation of 3000 feet.

Littorella lacustris, L. — First recorded by Watson from Corvo in
1842, but not again collected in the group until 1914, when I found
it in abundance on Pico. That it exists on San Jorge is highly
probable.

Lysimachia nemonim, L. — Under the name of L. azorica, Hornem.,
this was at first regarded as a distinct species, and it was so viewed
by Watson, though he speaks of it as nearly allied to L. nemorum.
However, the two are united in the Index Kewensis as well as in the
monograph by Pax and Knuth on the Primulacece in the Pflanzenreich
series (1905). During the last half of March 1913, on the slopes
of Pico, I found it in leaf and fruit, but rarely in flower. In June
and July of the follo-w-ing year it was abundantly in flower. It is
one of the most characteristic plants of the upland moors of Pico,
2000 to 4000 feet ; but when it finds protection in the beds of Heather
(Calluna) it may extend far up the steep lava slopes of the mountain,
even to 5600 feet. Seubert, who, it may be remarked referred it to

THE AZORES

438

the Linnean species, adopts Hochstetter's altitudes of 1000 to 3000
feet.

Menziesia polifolia, Sm. — In the first week of April on the slopes
of Pico it merely carried the last year's dried fruits with seeds. In
June and July it was in abundant bloom. Though it occurs in the
greatest profusion on the scantily vegetated lava slopes of the central
cone, extending from 5000 feet to the summit, it is also a characteristic
plant of the higher levels of the upland moors 3000 to 4000 feet and
may reach down to 2500 feet. Hochstetter refers it to the highest
zone on Pico, namely, above 5000 feet, and it is certainly most typical
of those levels. Though probably distributed over nearly all the
islands from Terceira westward, it has apparently not been recorded
from either San Miguel or Santa Maria, the two easternmost and
best-explored islands of the group.

Myrica faya. — Flowers according to Seubert in May and June,
On Pico it ripens its fruits at end of July and in August. Trelease
in his list of localities names all the islands except Terceira and San
Jorge. I found it on the first named, and recognised it on the steep
slopes of San Jorge from the steamer's deck. It is one of the most
characteristic trees of the lower woods of the Azores, and Seubert
remarks (following Hochstetter) that it occurs on all the islands
up to 2000 feet. This, as I found, is the usual upper limit both on
Pico and on San Miguel, and where it extends three or four hundred
feet higher it no longer forms a conspicuous feature of the vegetation.
At times one may find it growing in the bottom of a deep gulch
higher up the slopes of Pico. Thus I noticed it growing under these
conditions at an altitude of 3300 feet, where it had found protection
from the prevailing strong winds at these heights. My guide was
much surprised, and on his pointing out to me the usual upper
limit of the tree I found it to be about 2000 feet above the sea. It
descends to the coast, where it may be seen on old lava-flows and on
steep declivities. The island of Fayal is said to have derived its
name from this tree ; but there is a coast village of the name at the
south-east corner of San Miguel; and a town, river, headland^
and islet on the north-east coast of Madeira are thus called. The
Azores were occupied by the Portuguese about thirty years after
the occupation of Madeira in 1420, and the connection between the
tree-name and the place-name is by no means free from doubt.

In Lacerda's Portuguese and English Dictionary (1871) " Faia
or " Faya " is the proper name for the Beech, and " Faial " is
" a place where beech trees grow, or a plantation of beech trees."
Prof. Henriques, who very courteously replied to my queries in the
matter, tells me that Fagus sylvatica is not met wuth in Portugal,
It is, however, curious that George Forster, who visited the island
of Fayal in the Resolution in 1775, speaks of the " great quantities
of beeches called faya," naming the genus Fagus {Voyage round the
World, 1777, II., 581-604). In Portugal, as Prof. Henriques in«
forms me, Myrica faya is known as " Faia das ilhas," or " Faia of
the Isles."

This brings me to remark that this tree has long been established
in different parts of Portugal. Indeed, Dr. Christ in his paper on

F F

^4 PLANTS, SEEDS, AND CURRENTS

the Canarian flora (Engler's Jahrbucher, bd. VI., 1885) apparently
implies that it is indigenous in the Portuguese mountains. Prof.
Henriques, who tells me that possibly we might to-day consider it
as almost indigenous in the mountains of Algarve, the southern pro-
vince of Portugal, gave me Brotero's reference to it in the Flora
Insitanica : " Hab. quasi spontanea in pineto regione circa Leiria,
Cintra, etc., ex insula Fayal et aliis Azoricis advecta." B. A. Gomes
and Da S. Beirao in their catalogue of the plants in the botanic
garden of the medical school of Lisbon (1852) speak of Myrica faya
as the " Faya of the Isles " and under its habitat name Madeira,
the Azores, and Algarve in Portugal. Here " Faya " is also given
as the name of two European species of Poplar, Populus alba,
the Faya branca " or " White Poplar," and P. tremula {nigra,
H.B.G.), the " Faya preta " or Black Poplar." They also speak
of " Samoco " as another Portuguese name of Myrica faya, a name
also supplied to me by Prof. Henriques; but I can find nothing
about its significance.

Myrsine africana, L. — The " Tamujo," or " Tamucho," or "Tamuzo"
of the Azoreans, the final vowel being dropped in the vernacular.
The early Portuguese colonists evidently gave it the name of plants
of similar appearance in their home-land. In Portuguese and Spanish
dictionaries the name is applied to Rhamnus lycioides, but Prof,
Henriques tells me that in Portugal it is given to Securinega huxifolia.
The earlier botanists regarded the plant as a species of Buxus, and
its appearance might suggest it.

Watson and Trelease refer it to the variety retusa of De Candolle ;
but this variety is not differentiated by Mez in his work on the
Myrsinacece (Pflanzenreich, 1902). It flowers in April and May
(Seubert). Evidently the shrub bears the ripening fruit through
the winter. In the Furnas Valley at the end of February I found
it in nearly mature fruit. Druce, who visited this locality in March,
speaks of the plant's copious berries covered with bloom {Journ.
Bot., Jan. 1911). On Pico in the latter half of March it was fre-
quently observed by me in mature fruit. At the end of June and
the beginning of July it carried only immature green fruit. These
shrubs begin to appear on Pico about 600 or 700 feet above the sea.
Though abundant in the Faya zone, that is, below 2000 or 2500 feet,
it extends in quantity considerably higher, as far, in fact, as the upper
woods go, namely, to 4000 or 4500 feet; and in a dwarfed form it
ascends in places the steep lava slopes of the central cone, the extreme
altitude noted being 5200 feet. Hochstetter's observations gave
similar results, since he places it in the lower and upper woods ranging
between 1500 and 4500 feet. It grows in a stunted form on the
summits of the principal mountains of San Miguel, the highest of
which rises to nearly 3600 feet.

Osmunda regalis, L. — Recorded in Trelease's pages from Corvo,
Flores, Fayal, Terceira, and San Miguel. I found it characteristic
of Pico ; but although seemingly Seubert did not include this island
in his list of localities, this fern is named (p. 6) amongst the plants
characterising the lower mountain woods of Pico. It was in these
woods at altitudes ranging from 1200 to 2500 feet that this fern

THE AZORES

435

often came under my notice, both on the great mountain and in the
lake district to the east of it. In all probability Osmunda also
grows on San Jorge.

Per sea indica, Spr. ( = Laurus indica of Lowe's Madeiran flora). —
The " Vinatico " of the Azores and Madeira. Evidently exists or
did exist in nearly all the islands of the Azores ; but there is a doubt
about its nativity. Scubert, who was dependent on the Hochstetters
for his information, does not mention it ; and Watson remarks that
as seen by himself in Fayal and Flores the tree had a questionable
claim to be considered indigenous. However, Drouet refers to entire
woods of it in the other islands. Trelease gives no opinion on the
matter; but the symbol used indicates that he regarded it as indi-
genous. Yet, considering that the tree is entirely confined to the
Macaronesian islands, it would not be a subject for surprise if it was
indigenous in the Azores as well as in Madeira and the Canaries.
We have seen that a number of peculiar Macaronesian species {Ilex,
RhamnuSy Picconia, Laurus, Myrica, etc.) give a common character
to the w^oods of all the three groups and the exclusion of this handsome
tree from the list can on this ground scarcely be justified. I found
it growing commonly in colonies in the woods at the back of Magda-
lena, Pico, two miles inland, and 600 to 800 feet above the sea. The
trees, fifty feet in height, were in early fruit in the latter part of March,
whilst great numbers of the previous year's seeds lay germinating
on the ground beneath the trees, often forming seedlings five or six
inches high. Solitary trees are to be noticed in the gardens. As
elsewhere observed, the fruits are a favourite food of Azorean and
Canarian pigeons.

Picconia excelsa, DC. ( = Notelcea excelsa, Webb). — The " Pao
braneo " of the Azores and Madeira, and the " Palo bianco " of the
Canaries. Seubert states that this tree flowers in May. I found it
on Pico in flower in April. It probably exists or did exist on all the
islands; but its hard timber is much appreciated by the Azoreans,
and on the mountain of Pico it only escapes destruction by taking
refuge in some inaccessible gulch or small crater. I only came
upon three or four solitary trees in the woods of the great mountain
of Pico at altitudes of 1000 to 2000 feet. They are said to be more
frequent off the mountain, as on the slopes above Lagens. Seubert,
whose work is concerned with the Azorean flora in the first half of
last century, alludes to this tree as a constituent of the lower mountain
woods of Pico, that is, below 2500 feet, and as occurring in nearly
all the islands at elevations of 2000 to 3000 feet (Hochstetter), though
rather uncommon. Drouet remarked that in his time (1857) it
was more frequent on Santa Maria than elsewhere. In some islands,
as in San Miguel, where it used to be planted with the Faya for the
protection of the Orange trees (Seubert), it was, however, truly
native (Hunt quoted by Watson). Lowe states that it is very
rare in Madeira, growing to a height of forty to sixty feet, one or
two trees together. It there flowers, February to July. Fruits,
August to September.

Polygala vulgaris, L. — It is remarkable that this plant has only been
found in the Azores on the island of Pico. Since it was collected

436 PLANTS, SEEDS, AND CURRENTS

there by the Hochstetters in 1838 no other botanist has discovered
it in any of the other islands. Its vertical distribution on the great
mountain is stated in Seubert's work, from information supplied
by Hochstetter, to range from 4000 feet almost to the summit.
However, I found it at lower levels. It is a characteristic plant of
the upland moors and of the grassy intervals in the open woodlands
between 3000 and 4000 feet, and it grows under the same conditions
off the mountain in the lake district to the eastward at an altitude
of 2500 feet. On the exposed higher slopes of the great cone, amongst
the ashes and the old lava-flows, it seeks the protection of the beds
of Calluna vulgaris, and in this manner reaches almost to the summit.
Details of its occurrence in these high levels are given on previous
pages. It in all probability grows on the uplands of San Jorge.

Rhamniis latifolia, L'Her. — The " Sanguinho " of the Azoreans,
a name suggested by the reddish hue of the wood. This small tree,
which behaves in winter as a sub-evergreen, apparently retaining
its summer foliage in the mild winter, attains a height usually of
ten to fifteen feet, at times reaching twenty feet. It flowers in May
and June, and matures its fruit in July and August. In Seubert's
work it is stated to be common in the woods of all the islands, extend-
ing up to nearly 3000 feet, and in the zones of vegetation on Pico,
which he gives (p. 6) from the notes of the Hochstetters, he places
it in the lower- woods zone, that is, below 2500 feet. This corresponds
w^ith my own observations on the mountain, where I found it most
typical of the lower woods below 2000 feet, but frequently reaching
to 3000 feet. It shows itself shortly after one passes the cultivated
zone in the ascent of the mountain, namely, at 1000 feet. The
island of Pico is not mentioned in Trelease's list of localities, which
include Flores, Fayal, San Miguel, and Santa Maria; but, as has
just been implied, it was found there by the Hochstetters as far back
as 1838. Lowe, writing in the middle of last century, indicates that
in Madeira it was then apparently extinct as a wild plant.

Sibthorpia europcea, L. — Distributed over the group. Common in
the upland moors of Pico between 2000 and 4000 feet and extending
at times to nearly 5000 feet. Hochstetter gives it an altitude of
about 4000 feet on Pico. It occurs on the summit of Pico da Vara,
the highest point of San Miguel, 3570 feet above the sea. On Pico
it was in flower and fruit in July, the flowers examined having five
calyx segments. Several years ago I kept some English plants
under observation in South Devon. Both out of doors and under
cover most of the fruits failed to mature, and only a few dehisced,
behaviour which seems to indicate the northern limit of the climatic
conditions suitable for the species.

Taxns baccata, L. — The " Teixo " of the Azoreans. Watson re-
marks that he had no confirmation of its existence in the mountains
of these islands, alluding to a report to that effect mentioned by
Seubert. However, Drouet refers to it as growing in 1857 on Flores,
but beginning to be rare, the w^ood being much valued by cabinet-
makers. Trelease, who visited the group forty years later, writes
that it " formerly occurred in workable size on Corvo and Flores,
whence it was exported as a source of royal revenue. Now seemingly

THE AZORES

437

exterminated." However, it still exists in the island of Pico. In
1914 I came upon a few young trees in the woods at the back of
Caes-o-Pico at an altitude of nearly 2000 feet, and was informed that
more grew on the sides of gulleys in the mountains behind San
Roque, which lies a little more to the east. The Pico islanders are
familiar with the tree by reputation, though as it has long been
very scarce, but few could have seen it growing in the woods. In
fact, the tree was first described to me on the other side of the island
by men who knew it only by reputation as supplying good timber
for houses. At Praynha do Norte I was told that up to recent times
the wood of the " Teixo " was to be seen in a few of the oldest houses.
As already remarked a lake in the mountains behind San Roque is
still known by some as the " Lagoa das Teixas " (Taxus), though
the tree must be almost extinct there now. According to Walker
the old Portuguese historians of the group of the sixteenth century,
and Linschoten at its latter end, described the Teixo as abundant
on Pico. Linschoten especially noticed that this Pico tree was
known for its " excellent and princely wood." Coming down to
later times, Dr. Webster in his Description of the Island of St. Michael,
Boston, 1821, writes that " the wood of Pico appears to be a species
of yew. Considerable quantities were formerly sent to Lisbon,
where it was manufactured into work-tables, desks, etc." (p. 214).

Lowe includes Taxus baccata amongst the indigenous trees of
Madeira ; but it is characterised by him in the middle of last century
as being very rare.

As regards the dispersal of this tree by birds, reference is made in
an article in the Times on Bird Gardeners (October 16, 1915) to the
distribution of the fruits of churchyard Yews in Breconshire by
missel-thrushes, which drop the undigested seeds on rocky crags
a thousand feet up the mountain slopes, where young Yews sub-
sequently spring up. These birds, according to Ogilvie-Grant
(Novit. Zool., XII., Jan. 1905), are very rare stragglers in the Azores.

Vaccinium cylindraceum, Sm. — The " Romano " or Romani " of
the Azoreans. Flowers in May and June. Begins to form fruit
in the latter half of July and matures it in August. Seubert, relying
on Hochstetter, gives its vertical range on Pico as 1000 to 5000 feet.
This exactly corresponds with my observations. Above 4000 feet,
when it ascends the scantily vegetated precipitous lava slopes, it
becomes stunted ; and at the highest levels observed, 5000 to 5200
feet, it found shelter in the Calluna beds, where it was only a few
inches high. In the woods it often attains a height of nine or ten
feet, and when particularly luxuriant in its growth, as in the humid
plains of the lake district, it may reach fifteen feet ; but it is then
almost straggling in its habit.

Viburnum tinus, L. — The Laurestinus of our gardens. In England
it flowers in midsummer and midwinter, and evidently it fruits
twice in the year, namely, at the end of summer and in April. Arcan-
geli states that it flowers in the Mediterranean region in January
and August. In the Azores according to the observations of Drouet
and myself it flowers in April and May, showing the early flower-
buds at the end of February and in March. It ripens its fruits in

438 PLANTS, SEEDS, AND CURRENTS

the end of June and in July. But since on the higher slopes of the
mountain of Agua do Pao (San Miguel) it presented itself in mature
fruit as well as in early flower-bud at the end of February, it would
seem that there may be a second flowering in the early winter,
though I fancy that this is exceptional. Trelease apparently found
the plant in fruit in summer.

Seubert, relying on Hochstetter, states that it occurs in the moun-
tain woods of the Azores between 1000 and 2000 feet. This corre-
sponds with the results of my observations on Pico, where it ranges
from levels of 700 or 800 feet, where the cultivated zone gives place
to the lower woods, up to 2000 feet. On the slopes of Agua do
Pao in San Miguel it ascended to 2500 feet, but in the condition of
scrub. As Seubert observes it is rather uncommon in the group,
but I may add that it is frequent in places. Seubert (1844) gives
Fayal and San Miguel. Watson (1870) adds Flores and Corvo.
Trelease adds Santa Maria, and I have added Pico. When San
Jorge is better known botanically, the existence there of this shrub
will probably be established. On Pico it seems to be far from
abundant. Only at times one comes upon it in the wooded region
at the western end of the island; but it is fairly frequent in the
vicinity of Cabeza Grande. On the south side, corresponding to
the great mountain, it may perhaps be rather more frequent ; but
it is never generally distributed. My notes contain no reference to
it either on the other slopes of the mountain or in the lake district
to the eastward.

Its leaves are subcordate and broader and more obtuse than
European specimens; and Trelease distinguishes it as an Azorean
variety, subcordatum, remarking that it is apparently more closely
related to the Canarian V. rigidum than to V. tinus of the Mediter-
ranean region. Probably the Canarian species is a derivative of
that species (H.B.G.).

Summary

1. Before dealing with the modes of dispersal of the plants of
the Azores, it is observed that whilst the connection between the
plants of the woods of this group and those of Europe is either broken
or breaking, it is still kept up with Madeira and the Canaries. In
the case of the plants of the mountain moors and of those of the
ponds and lakes the connection with Europe has been sustained
down to recent times (p. 417).

2. The plants of the woods would in most cases be dispersed by
frugivorous birds, such as pigeons ; and it is remarked that the break-

• ing of the link with their European home, as indicated by their specific
or varietal differentiation, corresponds with the subspecific or varietal
differentiation of the pigeons of the Macaronesian islands (p. 418).

3. The minute seeds or small seed-like fruits of the plants of the
upland moors would probably be transported in mud adhering to
birds' feet or in their plumage. The capacity possessed by Luzula
and Juncus seeds of sticking firmly to a bird's feathers after being
wetted is observed; but it is remarked that these small-seeded
plants often raise other questions than those of dispersal (p. 419).

THE AZORES

439

4. In the case of the aquatic and subaquatic plants it is shown that
whilst those with small seeds, such as Peplis, Littorella, etc., would
be dispersed by waterfowl that would be likely to carry dried mud
on their feet and legs, others like Potamogeton, Carex, Scirpus, etc.,
possess small fruits that are known to be swallowed and ejected
unharmed by waterfowl (p. 420).

5. As in temperate latitudes, currents have not taken a prominent
part in stocking the seashore plants of the Azores with their plants^
unless we include the intermediate agency of the drifting log; andi
appeal is made to a variety of other dispersing agents (p. 420).

6. In regard to the strenuous appeal of Wallace for the paramount
influence of winds over birds in transporting small seeds like those
of Sagina and Orchis over tracts of ocean 1000 miles in width, it is
remarked that although there seems to be no question about the
fitness of the spores of cryptogams for dispersion by winds across
the ocean it is concerning the seeds of flowering plants that doubts
would be raised. In this connection the results of the experiments
of Lloyd Praeger on the falling rates of seeds are utilised to show that
the great contrast in weight between the smallest seeds of flowering
plants and the spores of cryptogams reflects the difference between
inefficient and efficient dispersal by winds over great distances.
Though so minute in size and so light in weight, the seed of an orchid
falls through the air at least fifty times as fast as an ordinary mush-
room spore. To counteract the effects of gravity, as measured by
the falling rates of seeds and spores, an initial elevation at the starting-
place must be assumed ; and it is shown that before a wind blowing,
at the speed of fifty miles an hour, the initial altitude requisite for
a spore or seed to reach the Azores from the European sea-borders^
would be only a few hundred feet for a mushroom spore and nearly
ten miles for an orchid seed. It is shown, however, that with
" plumed seeds," such as those of Typha and Epilohium, the difficulty
is not quite so great; but even here an initial elevation of 20,000
feet would be required in the first case and of 35,000 feet in the second
case to reach the Azores. It is urged that the up-draught on the
slopes of lofty mountains would provide the initial altitude for
cryptogamic spores and perhaps also for plumed seeds of the types
above named. But this would be impossible both for the seeds of
orchids and for the pappus-fruits of Composite plants, like Senecio
and Sonchus, where initial elevations of nine or ten miles would be
needed (p. 422).

7. The last part of the chapter is devoted to notes on the plants
of the Azores (p. 425).

LIST OF WORKS DEALING WITH THE PLANTS OF THE AZORES OR
QUOTED IN THE DISCUSSION IN THIS AND THE TWO PRECEDING
CHAPTERS

(See also list of works on Azorean botany in Trelease's paper below mentioned.)

Ball, J., The Mountain Flora of the Great Atlas, given in Hooker's book on Marocco

below named.
Beirao, C. M. F. da S. See under Gomes.
BoiD, Description of the Azores : London, 1835.

440 PLANTS, SEEDS, AND CURRENTS

Bullab' H Winter in the Azores : London, 1841.

Cardot, J., The Mosses of the Azores, Eighth Annual Report of the Missouri Botanical

Garden : St. Louis, 1897.
Chaves, F. A., Gisements de Diatomees fossiles k Furnas (He de S. Miguel), Bull.

de la Sac. Portug. des Set. Nat., II., 1909 : Lisbonne.
-Christ, D. H., Vegetation und Flora der Canarischen Inseln, Engler's Botanische

Jahrbucher, VI., 1885.
, Spicilegium Canariense, Engler's Botanische Jahrbucher, IX., 1887-8.

-Droitet, H., Catalogue de la flore des lies Agores : Paris, 1866.
JDruce, G. C., Plants of the Azores, Journal of Botany, January 1911, and in The
Chemist and Druggist about the same year.

^FoBSTER, G., Plantse Atlanticae ex insulis Madeirse, S'i Jacobi, Adscensionis, S*^
Helen ae, et Fayal reportatae, Commentationes Societatis Regice Scientiarum Gotting-
ensis, Vol. IX., 1787 : Gottingae, 1789.

GoDMAN, F. DU C, Natural History of the Azores : London, 1870. (The botanical

section is by Watson.)
Gomes, B. A., and C. M. F. da S. Beirao, Catalogus Plantarum Horti Botanici Medico-

Chirurgicae Scholae Olisiponensis : Olisipone, 1852. (List of plants introduced

from various parts of the world.)
GUPPY, H. B., Notes on the Native Plants of the Azores, Bulletin, Roy. Bot. Gard.

Kew, 1914.

HARTrNG, G., Die Azoren : Leipzig, 1860. (Descriptive of the geology of the islands ;

but about forty pages are devoted to the flora, the materials mainly derived

from Seubert, Hochstetter, and Watson.)
Hemsley, W. B. a few remarks on the Azores in a discussion of the floras of the

Canary and Cape Verde groups, Science Progress, II., 379, 1894.
Hochstetter, C. See under Seubert.

Hooker, J. D., Insular Floras, Brit. Assoc., 1866; Marocco and Great Atlas, 1878.
Hunt, Caeew, Descriptions of the islands of St. Mary and St. Michael in the Azores,
Journ. Roy. Geogr. Sac., XV., 258, 1845. (Botanical remarks are scanty.)

Linschoten, J. H. VAN. An account of his sojourn in the Azores, about 1589, is
given in " Purchas, His Pilgrimes," edit. 1905, Vol. XVIII., derived from the
original account of his voyages.

Lowe, R. T., A Manual Flora of Madeira, 1857.

Masson, F., Account of San Miguel, Philos. Trans., 1778.
Mayob, F. S., Traveller's Guide to St. Michael's, Ponta Delgada, 1911.
Mobelet, a., lies Agores, L'Histoire Naturelle : Paris, 1860. (Contains valuable
remarks on the flora.)

Seubebt, M., and C. Hochstettee, Ubersicht der Flora der azorischen Inseln, Wieg-
mann's Archiv fur Xaturgeschichte, Jahrg. IX., band i. : Berlin, 1843.
J'lora Azorica, by Seubert, from the collections and notes " Hochstetteri patris et
filii": Bonn, 1844.

Trelease, W., Botanical Observations on the Azores, Eighth Annual Report of the
Missouri Botanical Garden : St. Louis, 1897.

Walker, W. F., The Azores, 1886.

Wallace, A. R. Discussions of the Azorean flora from the standpoint of dispersal

in his works on Island Life, 1880, and Darwinism, 1889.
Warnstorf, C, Sphagnaceae, Pflanzenreich, heft 51 : Leipzig, 1911.
Watson, H. C, Botany of the Azores. See Godman above. Also earlier papers

in the London Journal of Botany, Vols. II., 1843; III., 1844; VI., 1847.
Webster, J. W., Description of the Island of St. Michael, etc. : Boston, 1821 (mainly

geological).

APPENDIX

List of Notes

Note 1. The time occupied by bottle-drift in the traverse in the
Main Equatorial Current from the Gulf of Guinea to the
coast of Brazil and to the West Indies.
2. The local beach-drift of the Turks Islands.
„ 3. The effects of wind-pressure on some of the shrubs of the

more exposed cays of the Turks Islands.
„ 4. On the experiments of Prof. Ch. Martins on the effects
of sea-water immersion on the fruits of Cakile maritima.
5. The synonymy of Sccevola plumieri, Vahl, and Sccevola
koenigii, Vahl.

„ 6. The strand plants of Teneriffe and of the north-east corner
of Grand Canary.

„ 7a. The plant- stocking of islets in the Florida Sea.

„ 7b. a comparison of the vegetation of sand-islets in the coral-
reef regions of the West Indies, and of the Pacific and
Indian Oceans.
8. The lake of the Grand Etang in Grenada.

^, 9. Guilandina honduc and other species.

10. Mucuna pruriens, DC.

11. The relation between the floras of Ascension and St. Helena

and the currents.
^, 12. Bottle-drift on the Azores.
„ 13. Bottle-drift in the Turks Islands.

14. Bottle-drift on the Bermudas.

15. The circuit of the North Atlantic accomplished by bottle-

drift.

16. Traverse of the North Atlantic by the derelict W. L, White.

17. Mr. Lloyd Praeger's experiments on seed-buoyancy.

„ 18. The differentiation of the Main and South Equatorial

Currents in mid-Atlantic.
„ 19. The Guinea Current.

„ 20. Bottle-drift from the South-east Bahama seas to the coast
of Ireland and back.

21. On some small-seeded West Indian littoral plants.

22. The Azores and their African connections as illustrated

by Sphagnum.

23. Pumice on the beaches of the Azores.
„ 24. Trailing growth of Anagallis tenella.

25. Sabine's record of the drifting of casks of palm oil from the
Gulf of Guinea to Hammerfest.

441

442

APPENDIX

26. A bottle-drift from Ascension to Guernsey.

27. Bottle-drift on the Canary Islands.

28. Bottle-drift on Madeira.

„ 29. Sargasso or Gulf weed in Azorean beach-drift.

30. Iguanas, snakes, and alligators in the Turks Islands.

31. Draccena draco (Dragon-tree).

32. A comparison of the old and later charts of the Turks

Islands.

33. Plants collected by George Forster in Fayal.

,, 34. Observations on the medanos or moving sand-hills of the

Ancon coast region in Peru.
„ 35. Bottle-drift in high latitudes of the North Atlantic.

36. The wells of Pico in the Azores.

37. Uncinia,

„ 38. The fruiting behaviour of Atriplex portulacoides, L., at

Salcombe, South Devon.
„ 39. Recent observations in the western Bahamas by Dr.
Vaughan and other American geologists.

Note 1 (p. 70).

The time occupied by bottle- drift in the traverse in the Main
Equatorial Current from the Gulf of Guinea to the coast of Brazil
and to the West Indies.

Since the data for bottle-drift at my disposal only apply to the
traverse west of St. Paul's Rocks and Ascension, it will be necessary
to supply the deficiency from an authoritative nautical publication.
In so doing we shall be able to compare results obtained by the
navigator with those supplied by the floating bottle.

It is highly probable that the drifting bottle in the first half of
the passage would travel eastward at a greater rate than twenty
miles a day, which is the average rate to the west of St. Paul's Rocks.
This is directly indicated in the Admiralty publication, the Africa
Pilot (Part I., p. 52, London, 1907), where we find the following
statement : " The Equatorial Current appears to attain its greatest
volume and velocity during the season of the northern summer.
From the African coast to about the 15th degree of west longitude,
the maximum strength, sixty miles a day, has been observed in
May and June, and during this period its direction is more regular,
being west (true). Westward of that meridian, at successive later
periods, or between July and October, it is probably subject to
irregularities in strength, depending on the winds."

This current is regarded in the pages of the work above named
as commencing in the neighbourhood of Anno Bom in the Gulf
of Guinea. From this locality to the West Indies (Trinidad and the
neighbouring islands) the distance along the track of the current
would be about 4000 miles. We can allow for the increased velocity
in the first third of the traverse from the Gulf of Guinea to the West
Indies by assuming an average drifting-rate of thirty miles a day
for a bottle over the whole distance. This gives a result of 133

APPENDIX

443

days, the estimate employed in my table being 118 days. It may
be remarked that Laughton gives the average velocity of the current
as twenty to thirty miles a day {Physical Geography, 1873, p. 187).
A considerably shorter time would be occupied by the current in
carrying a bottle from the Gulf of Guinea (Anno Bom Island) to the
coast of Brazil (Cape St. Roque), a passage of about 2500 miles. At
the average rate of thirty miles a day it would require twelve weeks,
which is the estimate accepted in this work.

We will proceed now with the discussion of the bottle-drift materials
employed in this treatment of the Main Equatorial Current. The
data may be arranged in the following groups : (a) those supplied
by the bottles thrown into the sea in the vicinity of Ascension, which
lies within the current but near its southern border; (b) those data
concerning bottles thrown into the northern portion of the current
in the vicinity of St. Paul's Rocks ; (c) those of bottles thrown into
the centre of the stream between St. Paul's Rocks and Cape St.
Roque ; (d and e) those of bottles thrown overboard off the Amazon
estuary.

(a) The Ascension Area. — Probably the slackest portion of the
current is near its southern border in the vicinity of Ascension.
In the case of three bottles thrown overboard on successive days
in February from a ship on the course between St. Helena and
Ascension the following minimum daily rates are supplied by Schott
(pp. 14, 27; Maps I. and IV.) :—

(1) 11-3 miles from a position half-way between these two islands

to Paranahiba on the coast of North Brazil.

(2) 11-7 miles from about 200 miles south-east of Ascension to

the Lesser Antilles (Grenadines).

(3) 18-1 miles from a position fifty or sixty miles south-east of

Ascension to Jamaica (Morant Bay).

Since the swiftest rate is afforded by the bottle that made by far
the longest passage (4017 miles), it is fair to conclude that there
was not the delay in its recovery that there was in the other two cases,
and probably nineteen or twenty miles a day would represent the
speed of its passage to the West Indies. It may be added that a
bottle dropped into the sea about 100 miles north-west of Ascension
in January 1822, which was picked up on Trinidad, gives a minimum
daily drifting rate of 15-6 miles (No. 45, Nautical Magazine, 1852).

(b) The St. PauVs Rocks Area. — Just as Ascension lies a little
within the southern border of the current, so St. Paul's Rocks lie
just within its northern border. There are, in the first place, at my
disposal data for thirteen bottles dropped over in mid-Atlantic
between the meridians of 22° and 32° W. and the parallels of 5° N.
and 2° S., most of the materials being supplied by the American
charts. Of these, nine were stranded on the West Indian islands
between Trinidad and Martinique (inclusive), giving rates during
passages of from 1900 to 2400 miles of 20, 19-8 17-2, 16, 16, and 14-4
miles a day in the six most rapid cases. The two greatest velocities
apply to bottles that were thrown over in March and November,

444

APPENDIX

the first being especially important, since the bottle was found by-
fishermen afloat off the island of St. Lucia, and the element of un-
certainty that attends most records of bottle-drift is thus removed
(Schott, p. 16). Of the other four bottles, one was stranded at
Cayenne in French Guiana, and three broke through the line of
islands of the Lesser Antilles, one of them reaching Porto Rico;
whilst the other two after crossing the Caribbean Sea entered the
Gulf of Mexico, one of them being stranded at Vera Cruz, and the
other ultimately arriving at the Florida keys. The last mentioned,
which was thrown over in the St. Paul's Rocks area in March, per-
formed a passage of nearly 4000 miles, its minimum daily drift rate
being computed in the American chart at 18-4 miles.

Dr. Schott (p. 16) gives an interesting series of records which con-
firm these results. Of three bottles dropped into the sea on different
days in January between 0° and 7° N. lat. and 27° and 31° W. long.,
that is to say, in the neighbourhood of St. Paul's Rocks, all were
found in the following May on different parts of the coast of Trinidad,
the respective daily rates indicated being 17-7, 17-1, and 17-0 miles.

(c) The Region between St. Paul's Rocks and Cape St. Roque. — If
bottles thrown into this current in mid-Atlantic near its northern
and southern borders are carried to the West Indies at the rate of
nineteen or twenty miles a day, it is likely that in the centre of the
stream they would attain a greater velocity. Dr. Schott (p. 16)
gives the rates for seven bottles placed in the sea during February,
March, and April, between St. Paul's Rocks and Cape St. Roque,
or a little to the eastward, namely, between the parallels 0° and 7° S.
and the meridians 27° and 32° W. They were all recovered on Trini-
dad and the adjacent island of Tobago, four of them giving minimum
daily rates exceeding twenty miles, the greatest being 27-2 miles.
We may take them as indicating an average velocity of at least
twenty-five miles during this part of the passage, and if we allow
for the speeding up " of the current on approaching the Brazilian
coast it is probable that the average velocity of the thread of the
current in the latter half of its traverse to the West Indies would
be nearer thirty miles a day.

(d) Off the Amazon Estuary and thence to the West Indies. — Accord-
ing to the known behaviour of this powerful current, its speed in-
creases greatly after passing Cape St. Roque, and we should expect
that bottles cast into the sea off the mouths of the Amazon would
be transported to the West Indies at a rate of from thirty to fifty
miles a day. The data for nine bottles, mostly derived from the
American charts, are here employed. They were thrown over in
March, April, and May of different years at a distance of from 200
to 300 miles from the mouths of the Amazon. As indicated by the
dates of their recovery on Trinidad and Tobago three of them per-
formed the passage of from 900 to 1100 miles at minimum daily
rates of 43-5, 36-1, and thirty-four miles. But the greatest velocity
recorded for a bottle thrown into the sea in this locality was attained
by one that was recovered on the Virgin Islands twenty-eight days
after its start, having accomplished a drift of 1400 miles at fifty miles
a day. This bottle was cast over with two others on the same day

APPENDIX

445

and in the same locality, about 200 miles off the Amazon estuary,
its two associates being afterwards stranded on Trinidad, the mini-
mum daily rates recorded being 43-5 and 36-1 miles (U.S. Chart
for the N. Atlantic, May 1909). The behaviour of these three bottles
is most instructive. Evidently there was considerable delay in
their recovery on Trinidad, and very little delay in the case of the
one that reached the Virgin Islands. We should probably, therefore,
not go far wrong if we assumed that in the last part of its oceanic
passage along the coasts of North Brazil and the Guianas the Main
Equatorial Current carries bottle-drift to the West Indian region
at the average rate of forty miles a day.

(e) Ojf the Amazon Estuary and thence to the Florida Coasts. — With
reference to the time occupied by drift in the passage from the
vicinity of the Amazon estuary to the Florida seas the following
data may be employed. The track assigned in both the American
and German maps to bottles that arrive on the coasts of
Florida from latitudes in the tropical Atlantic south of 10°
N. lies across the Caribbean Sea and through the Straits of
Yucatan. This is well illustrated by the drift of two bottles that
were dropped into the sea on the same day of April within twenty-
five miles of each other and about 130 or 140 miles off the coast of
French Guiana, the details of which are given in the U.S. North
Atlantic chart for May 1909. One was recovered in the Gulf of
Honduras 111 days afterwards, the distance of 1920 miles being
covered at a minimum rate of 17-3 miles a day (not 27-3 miles as
stated in error in the chart). The other was found on the east coast
of Florida north of the Straits in lat. 26° 56' N. Up to the date of
recovery 182 days had passed and the minimum rate over a distance
of 2640 miles is placed at 14-5 miles a day. Very remarkable is
it that a third bottle thrown over on the following day from the same
ship in lat. 10° N., and about six degrees east of Trinidad was recovered
143 days afterwards in the same place on the Florida coast, the
estimated minimum rate over a distance of 2400 miles being 16-8
miles a day. Since the bottle was recovered thirty-eight days before
the other, which was found in the same locality, it is probable that
it was picked up with but little delay.

Another record from this part of the Atlantic, though evidently
a belated one, concerns a bottle thrown over from the Prince Eugene
in March, about 300 miles north-east of the mouths of the Amazon.
It has already been mentioned in Chapter III. It was found on the
east coast of Florida in lat. 27° 30' N. 279 days afterwards, and
therefore farther north than the two bottles above referred to,
and like them it had been carried through the Florida Strait. The
distance as determined by the U.S. Hydrographic Office is 3320
miles, and the rate about twelve miles a day. From the foregoing
data it may be fairly assumed that an average daily rate of seventeen
miles between the Amazon coasts and the shores of Florida is not
an excessive estimate for bottle-drift. Taking the distance at 3200
miles, it would be covered in 188 days or about six months.

Doubtless the track taken by these bottles across the Caribbean
Sea and the Gulf of Mexico was also followed by a bottle, already

446

APPENDIX

referred to, which reached the Florida keys from the St. Paul's
Rocks area, travelling at a rate of not less than 18*4 miles a day.

Note 2 (p. 10).
The local beach-drift of the Turks Islands,

The beach-drift derived from strand plants growing on the Turks
Islands is often disguised by the mass of the foreign drift. But in
the islands where there are mangrove swamps, as on Grand Turk,
the germinating fruits and seedlings of the trees composing them,
Rhizophora mangle, Avicennia nitida, and Lagu7icularia racemosa,
are not infrequently thrown up on the beaches on the weather coasts.
Although it is safest to assume that most of them are of local origin,
some of the seedlings of Rhizophora mangle that I observed had all
the appearance of having been long afloat ; and it is likely that they
came with the foreign drift. Several of the stranded Rhizophora
seedlings, which had been more or less covered over with the Sargasso
weed that is heaped up in quantities on these beaches, had established
themselves firmly in the sand by rootlets three or four inches long.

The larger local drift other than that derived from the mangroves
is represented by the fruits of Coccoloha uvifera. However, much
of the local beach-drift is made up of the small seeds and seed vessels
of plants growing in the vicinity, such as Ipomoea pes-caprce, Sccevola
plumieri, Suriana maritima, Tournefortia gnaphalodes, etc. This
fine drift is sometimes sifted out by the waves and deposited higher
up the beach away from the heavier large foreign drift, where it is
generally associated with small rounded pumice pebbles 5 to 12 mm.
across.

Note 3 (p. 278).

The effects of wind-pressure on some of the shrubs of the more
exposed cays of the Turks Islands.

These effects are well exhibited in the two small wind-swept
islands of Pear Cay and Eastern Cay on the weather or eastern
borders of the group. The trade winds seem to blow home with
greater force on the weather cays, and it is here that the frequent
gales and the occasional hurricanes seem to expend much of their
repressive influence on the vegetation. The adaptive habit of growth
is strikingly shown in the cases of Corchorus hirsutus, Suriana mari-
tima, and Tournefortia gnaphalodes. They all at first bend prone
with the wind, the trunks and prostrate branches rooting in the sand,
held down firmly by rootlets several inches long, the subsequent
behaviour varying in the different plants.

In the case of Corchorus hirsutus the plant was prostrate along its
entire length, its leafy branches spreading out like a fan on the sand
and rooting freely and firmly, the whole measuring from ten to fifteen
feet instead of three or four feet, the usual height of the erect indi-
vidual. In such wind-swept stations it made no effort to assume the
upright position. On the other hand, with the shrubs of Tournefortia
and Suriana the erect habit ultimately asserted itself, the leafy

APPENDIX

447

branches rising into the air and conceaUng the original prostrate
growth. With Tournefortia gnaphalodes the main trunk branched
low down close to the ground, the primary branches lying prone
for a distance of two and a half or three feet and rooting firmly in
the sand; whilst from them sprang the secondary branches, which,
lying prostrate at first, finally arose erect and developed leafy stems
two or three feet in height. With Suriana maritima the secondary
leafy branches were upright and three or four feet high; but the
main stem and primary branches for a distance of two and a half or
three feet were prone and firmly held by their rootlets in the sandy
soil.

Note 4 (p. 188).

On the experiments of Prof, Ch. Martins on the effects of sea-water
immersion on the fruits of Cakile maritima (Bull. Soc. Botanique
de France, tome IV., p. 324 : Paris, 1857).

These experiments were made on the seeds and fruits of a large
number of plants with the object of determining the persistence
of the germinative capacity after long immersion in the sea ; but, as
I point out in my book on Plant Dispersal (p. 539), an objection
previously made by Thuret and Hemsley (Ibid.), the investigator often
leaves us in doubt, when speaking of the floating capacities, whether
he is referring to the initial or to the sustained buoyancy. His
remarks on some of the fruits, including those of Cakile maritima^
might lead one to suppose that germination occurred after forty-
five days' flotation in sea- water ; but it may be that only immersion
is implied, since he placed in the same category the fruits of Beta
vulgaris, Eryngium maritimum, Pancratium maritimum, Ricinus
communis, Salsola kali, etc., which, according to the observations
of Thuret and myself, sink in a few days. Lloyd Praeger places the
limit for Salsola kali at five and a half days (see Note 17).

Note 5 (p. 227).

On the synonymy of Sccevola plumieri, Vahl, and Sccevola
kcenigii, Vahl.

Before making the acquaintance of Sccevola plumieri in the West
Indies I was led by the occasional application of the name Sc. lobelia
to both plants to infer that they were forms of one species ; and Sc.
kcenigii was therefore credited in my book on Plant Dispersal with
a distribution over the tropics of the globe. Schimper in his Indo-
malayische Strandflora (p. 130) was led into a similar error, since he
states that Sc. plumieri is distributed over most tropical and sub-
tropical coasts of both hemispheres.

The exceedingly puzzling synonymy has been in recent years
made clear in the monograph of the Goodeniacece by Krause (Das
Pflanzenreich, IV., 277, 1912). The two plants, as was evident
to me when I first met Sc. plumieri in the West Indies, are quite
distinct, and could not be mistaken by any one with both before him.
The German author, who refers them to different subgroups of the

448

APPENDIX

genus, points out (p. 18) that the confusion of the two species has
frequently given rise to very inaccurate accounts of their distribution.
The difficulty seems to have arisen in connection with the early
use of the specific name of lobelia as imposed by Linnaeus. Krause
in re-examining the whole question must have experienced some
difficulty in the process of selection, and it is not surprising that there
is an omission here and there. Thus I found Sc. kcenigii to be in
1888 a characteristic plant of Keeling Atoll, where it had been pre-
viously collected by Darwin in 1836, the list of his plants being deter-
mined by Henslow {Ann. Nat. Hist., I., 337, 1838; Chall. Bot., IV.,
113; Journ. Vict. Inst, London, 1889).

Note 6 (p. 407).

The strand plants of Teneriffe and of the north-east corner of Grand

Canary,

I examined the strand vegetation at various places on the coast
of Teneriffe, namely, between S. Juan de la Rambla and Orotava,
at Punta Hidalgo and in its vicinity, at Taganana and Armasiga,
between Santa Crux and S. Andres, and to the south of Santa Cruz.
The shore was mostly rock-bound, the beaches being generally few
and scanty, so that the littoral plants as a rule were those that find
their home on coastal rocks and on sea-cliffs as well as on the beaches.
However, the beach flora was well developed on the sandy isthmus
connecting La Isleta with the north-east corner of Grand Canary.
But a much more extended acquaintance with the group would
be required before one could venture to discuss the shore flora of
the Canary Islands as a whole. Here there is merely offered a con-
tribution to the subject from the standpoint of dispersal.

In addition to several plants familiar on our English beaches,
such as Atriplex portulacoides. Beta maritima, Crithmum maritimiim.
Euphorbia par alias, etc., there were a number of others, that either
do not extend north of Southern Europe and the Mediterranean
region or are confined to this and other Atlantic archipelagos (Azores,
Cape Verde Islands), such as Frankenia ericifolia, F. pulverulenta,
Mesembryanthemum crystallinum, M. nodiflorum, Zygophyllum, etc.
Then there was the local element, which we should expect to find
in all strand floras where the inland plants come down to the coast.
Thus in places those strange-looking shrubs, the cactoid Euphorbia
(E. canariensis) and Plocama pendula, which so often give a character
to the barren hill-slopes of basic tuffs and lavas that descend steeply
to the sea-border, come down to the coastal rocks, where they associate
with typical shore plants like Crithmum maritimum and Zygophyllum,

Amongst other strand plants of Teneriffe may be mentioned a
Statice and a stout fleshy yellow umbellifer unknown to me. Both
grow on the coastal rocks and ascend the precipitous lava slopes for
100 or 200 feet or more. The umbellifer is remarkable on account
of the greenish-yellow hue of the whole plant, its leaves being deeply
cut into three cuneate lobes indented on their upper border. I
may remark that in addition to the ordinary form of Crithmum mari-

APPENDIX

449

timum, where the separate carpels arc about 6 mm. long and about
4 mm. broad, there is a variety with longer and relatively narrower
fruits (9 or 10 mm. long, 4 mm. broad), which seems to be confined
to lava rocks at the coast, and does not like the usual form grow
also on the beach.

The locality in which I found the strand flora most developed
was on the west side of the low sandy isthmus which connects La
Isleta with the north-east corner of Grand Canary. Euphorbia^
paralias was the most frequent of the beach plants and extended
inland for some hundreds of yards over the dunes. Amongst other-
plants growing on the sandy shore were Atriplex portulacoides,
Frankenia, Heliotr opium, Mesemhryanthemum crystallinum, M.
nodiflorum, Zygophyllum, etc. The last named also grew along the
upper drift line where the beach was shingly and on the rocks border-
ing the beach at La Isleta.

A few remarks on the modes of dispersal of some of these plants
may here be made. We cannot exclude human agency in the case
of the two species of Mesemhryanthemum, which were extensively
cultivated in the group in the eighteenth century for the extraction of
soda, according to Samler Brown's Guide to the Canary Islands (1905,
d,^). These two plants grow also on the Salvages (Lowe's Florulce
Salvagicce Tentamen, 1869), and were employed in making barilla
(soda) by men engaged in the trade, who often visited the islands for
that purpose (Ibid.). The dispersal of the carpels of Crithmum
maritimum across the sea by the currents and locally by the winds
is discussed in my book on Plant Dispersal (p. 542). It is there
remarked that they are very buoyant and can float for several
months in sea- water. They are so light that a strong wind blows
them along the beach and up the faces of the sea-cliffs. (More
recent experiments showed that the carpels in some cases germin-
ated after floating for thirteen months in sea-water.)

I experimented on the fruits of a species of Zygophyllum that
flourished on the beach of the low isthmus connecting La Isleta
with the north-east corner of Grand Canary. It is probably Z.
fontanesii, a littoral plant found also in the Cape Verde Group (Schmidt
and Coutinho) and on the Atlantic coast of Morocco (Hooker, p. 339).
From the results of the experiments below given it may be inferred
that the species tested has but a limited capacity for dispersal by
currents. It might, however, accomplish a sea-passage of from
100 to 200 miles. This would be quite sufficient for its derivation
in the case of the Canary Islands from the neighbouring African
coast and for its distribution over that group.

The dry cocci of this species of Zygophyllum are 7 to 8 mm. long.
They possess a solitary crustaceous seed (2-5 mm. in length) in the
midst of spongy air-bearing tissue, and are so light in weight that
like the carpels of Crithmum maritimum they are blown about on
the beach by the winds. They would have possessed similar great
floating powers, did they not tend to gape at the inner angle. As
it is, the sea-water soon penetrates through the opening, and in
consequence they float for only eight or ten days. The seed itself
sinks.

G G

450

APPENDIX

From experiments made on the fruits of Atriplex portulacoides
growing at Salcombe in South Devon (see Note 38 of the Appendix),
it was evident that whilst the seed-hke fruit sinks it can float when
surrounded by the perianth between two and four weeks, buoyed up
doubtless by air-bubbles. It thus might easily have been carried
by the sea to the Canary Islands from the adjacent continental
coasts. On the other hand, in the case of Beta maritima, which occurs
in Madeira and in the Azores as well as in the Canaries, the direct
action of the currents must be excluded, since the buoyancy of the
•fruit is limited to a day or two (Plant Dispersal, p. 542). Three
other of the shore plants of this group. Euphorbia paralias and the
two species of Frankenia, niay here be noticed from the standpoint
of dispersal. The seeds of the first named float for a long time
unharmed in sea-water (Ibid., p. 543) ; whilst the very small seeds of
Frankenia are probably distributed by birds.

Note 7a (p. 10).
The plant-stocking of islets in the Florida Sea.

One of the most methodical series of observations on the stocking
of islets in coral-reef regions with plants are those made by Mr.
Lansing (junior) in 1904 on the sand-keys of Florida to the westward
of Key West. He had been commissioned by the Field Columbian
Museum of Chicago to carry out this inquiry. He collected speci-
mens of everything he saw, noting carefully the plant arrangement
an each islet, and laying down his results on maps made on the spot.
His collections, together with his comprehensive notes and maps,
supplied materials for a detailed consideration of the flora of these
islets in a paper by Dr. Millspaugh published by the Museum in 1907.
" As was to be expected " (to quote from this paper), " this archi-
pelago proves to be vegetated with only the usual broad strand
species common to similar situations on the Antillean islands in
general." In discussing the results Dr. Millspaugh brought to bear
an experience derived from a wide field of study of insular and
strand formations in the Antillean region. The value of this paper
for us lies in its illustrating the process of plant-stocking in the case
of newly formed low islets in the West Indies.

These sand-keys vary greatly in size, the smaller being usually
from thirty to a hundred yards long, whilst the larger may measure
.a mile or more. Their elevation is generally two to four feet ; but it
may be as low as one foot and as high as nine feet. Of the nineteen
keys examined only three exceeded four feet. The numerous small
keys, consisting exclusively of mangrove colonies, are not specially
dealt with in this paper. They, however, represent the earliest stage
in the plant-stocking process. My remarks here will be mainly
restricted to a consideration of these results from the standpoint
supplied by my observations and experiments on the coral islets of
the Indian and Pacific Oceans, as well as by those on the small cays
of the Turks Group in the West Indies. In so doing I shall as a rule
be following Dr. Millspaugh' s guidance, though in my own fashion.

APPENDIX

451

Different stages in the process are readily distinguished. It
begins with the partial emergence of a bank of coral sand, which
under the influence of the currents gradually acquires a more or less
curved or crescentie form, its convexity facing the currents. For
convenience we will take a medium-sized key and will designate the
convex side of the bank as its weather margin. Whilst the bank is
still washed over by the seas in places, various floating seeds and
fruits, as well as seedlings, are cast up on its surface, those of the
mangroves, more particularly the seedlings of Rhizophora mangle,
establishing themselves under the shelter of the bank on its lee side.
Islets may remain in the condition of a mangrove colony for some
time. But as the exposed surface increases in extent typical beach
plants begin to establish themselves. The seeds of some are brought
by sea-fowl; but, as will be shown later on, the currents probably
do most of the work. One of the first to establish themselves on the
bank on the weather side is Sesuvium portulacastrum, and it is this
plant that Dr. Millspaugh places at the head of his list illustrating
the sequence of appearance of the most characteristic beach plants
on these keys. This is followed in the order fixed by this authority
by Cakile fusiformis. Euphorbia buxifolia, Cenchrus trihuloideSy
Cyperus hrunneus, JJniola paniculata, Andropogon glomeratus,
Suriana maritima, Tournefortia gnaphalodes, Borrichia arhorescens,
Iva imbricata, and Ambrosia hispida (A. crithmifolia).

Two strand plants not sufficiently frequent on these keys to be
included in the most representative plants, but amongst the first to
establish themselves through the aid of the currents, not only on
West Indian beaches, but also on new islets in the Indian and Pacific
Oceans, are Canavalia obtusifolia and Ipomcea pes-caprce. Their
place in the above list would be with the plants immediately following
Sesuvium portulacastrum. Another of the early plants would be
Sccevola plumieri, though it only grows on a few of the keys.

By the time that the sandy surface is well stocked with beach
plants the mangrove colony on the concave side of the bank has
increased extensively, and we notice that though in great mass of
Rhizophora mangle, two other mangroves, namely, Avicennia nitida
and Laguncularia racemosa, have established themselves on the
border facing the sandbank, where they are associated with Cono-
carpus erectus. The mud-flat in the neutral zone between the beach
plants and the mangroves is ultimately occupied by Salicornia
ambigua, Batis maritima, and Sesuvium portulacastrum.

We now approach the completed stage in the history of such a
key, a condition which it is likely to preserve, provided man does
not intervene, as long as the present relation between land and
water prevails. Be the islet small or large, a limit to its growth at
the borders is reached in the deeper water, both on the weather side,
where the waves cease to heap up the sand, and on the lee side,
where the Rhizophora colony no longer extends seaward. Through
the reclaiming agency of the mangrove, the area of the swamp is
much reduced and the beach plants advance on the new surface.
The islet loses its crescentie form, and in the final stage it is mainly
appropriated by the beach plants, amongst which Suriana maritima

452

APPENDIX

often predominates in the interior with shrubs like Tournefortia
gnaphalodes on its weather border, and beyond them, reaching to
the w^ash-Hne of the sea, Euphorbia buxifolia, Cakile fmiformis,
Sesuvium portulacastrum, Ipomoea pes-caprce, etc.

In those cases where the original sand-keys lie close together and
are only separated by shallow channels the mangroves lead to their
ultimate union. Cases are cited in this paper where two keys>
separated at the time the islets were charted by the U.S. Hydro-
graphic Survey, were found by Mr. Lansing to be joined together.
Writing of the Marquesas Group of these Florida sand-keys. Dr.
Millspaugh says that through the growth of the mangroves and the
upwashing of the light coral sand by the waves all the keys will in
course of time unite to form a solid island embracing the whole
group. It is, however, instructive to note that this growth of islands,
whether singly or in combination, takes place under the conditions
of the present sea-level. We get no indication in this paper of the
formation of the seolian sandstone which has so long puzzled the
geologist both in the Bermudas and in the Bahamas. The con-
ditions for its development are not presented in the history of these
Florida sand-keys.

With reference to the means of dispersal through which these
keys received their plants. Dr. Millspaugh holds that the balance is
on the side of the bird, and he appeals mainly to the medium of the
feet of sea-birds. However, I have endeavoured to adjust our views
in the remarks made below on the probable mode of dispersal of the
nineteen plants he names as most typical of these keys, to which I
have added four which deserve a place in this treatment of the
subject of dispersal, namely, Ipomoea tuba {= Calonyction album),
Ipomoea pes-caprce, Canavalia obtusifolia, and Sccevola plumieri. A
grouping of the plants according to their probable mode of reaching
the Florida sand-keys is here presented. For particulars reference
should be made to other pages of this work, to my book on Plant
Dispersal, to my paper on Keeling Atoll, and to Dr. Millspaugh' s
paper.

(A) Plants brought by the currents, the seeds, fruits, seedlings, etc.,
being able to float long enough to reach these sand-keys : Avicennia
nitida, Batis maritima, Cakile fusiformis, Canavalia obtusifolia,
Conocarpus erectus, Ipomoea pes-caprce, Ipomoea tuba, Laguncularia
racemosa, Rhizophora mangle, Salicornia ambigua, Suriana maritima,
Tournefortia gnaphalodes.

(B) Plants brought by currents and frugivorous birds : Sccevola
plumieri.

(C) Plants brought through the adherence of their fruits to birds'
plumage : Cenchrus tribuloides. Euphorbia buxifolia ( Millspaugh' s
authority).

(D) Plants with small seed-like fruits that possess sufficient float-
ing powder to enable them to be brought by currents from neighbour-
ing coasts, but which could also have been transported in the crevices
of drifting logs : Ambrosia crithmifolia, Borrichia arborescens.

(E) Plants with small seeds or seed-like fruits, all non-buoyant.

APPENDIX

453

brought by drifting logs or attached to the feet of sea-birds : Cyperus
hrunneus, Dondia linearis, Iva imbricata, Sesuvium portulacastrum.

(F) Plants, like Uniola paniculata and Andropogon glomeratus,
that may have been brought, as Millspaugh suggests, by currents
( Uniola), or through the agency of birds {Andropogon), but concerning
which observation is needed.

Only the most characteristic plants are here dealt with. Quite
half of the twenty-three plants above named would owe their pres-
ence on the Florida sand-keys to the direct agency of currents. In
the case of a quarter, the agency of the drifting log could be appealed
to. Though one may be too much inclined to fall back on the
drifting log in cases of difficulty, its intervention is much more than
a mere possibility. On Keeling Atoll I found a stranded log honey-
combed by the Teredo, the empty burrows of which were filled by
sand, with which many of the small pyrenes of Tournefortia argentea
and other small seeds were mixed. With a high tide and a heavy
sea this log could have been swept off the beach and carried seaward.
Birds might have aided in the case of the remainder. Frugivorous
birds probably played a small part, since, if we except Sccevola
plumieri, but few of the plants would possess fruits that would
attract them. However, the plant just named was more probably
brought by currents. But one or two of the plants not named in
the list, such as Ernodea litoralis, might have been brought here in
this way. Dr. Millspaugh informed me that the seeds of Euphorbia
huxifolia become adhesive when moistened. So it has been placed
in the group with Cenchrus tribuloides. The attachment of the
prickly fruits of Cenchrus to one's clothes will be familiar to all who
have sojourned in the tropics, one of the American names of the
species above named being " claw-grass."

Of the plants in the first group some would be dispersed through
the floating seedling, as in the case of the species of Rhizophora and
Avicennia, and also of Batis and Salicornia, though with the last two
plants the seeds (Batis) and the detached seed-bearing joints (Sali-
cornia) possess independent buoyancy. The dispersal by currents
of Salicornia peruviana, S. herbacea, Batis maritima, etc., is dealt
with in my work on Plant Dispersal.

Note 7b (p. 5).

A comparison of the vegetation of sand-islets in the coral-reef regions
of the West Indies, and of the Pacific and Indian Oceans.

For this purpose the results of Mr. Lansing's observations on the
Florida sand-keys will be utilised, as given in Dr. Millspaugh' s
paper. Although the present writer has no acquaintance with the
Florida sand-keys, he formed a close acquaintance with nearly all
their characteristic plants on the shores of the Turks Islands. On
Keeling Atoll and on North Keeling Island, on the south coasts of
Java, in the Solomon Islands, and in Fiji, he became familiar with

454

APPENDIX

the plants with which currents and birds stock the newly formed
islets thrown up on the reefs of those seas. His first study in the
plant- stocking process of such islets was made in the Solomon
Islands in 1882-3, the particulars of which are given in his work on
those islands and in the Appendix of Mr. Hemsley's volume on the
botany of the Challenger expedition. Although the following remarks
mainly apply to the region of the Western Pacific, it might in most
respects apply to islets in the Indian Ocean, such as are presented on
Keeling Atoll and in the small island of North Keeling to the north
of it, many of the plants being the same.

There are some points of similarity as well as great points of con-
trast between the vegetation of reef-islets in the Western Pacific and
in the Florida seas. In appearance there is a great contrast, since
the large trees, often with handsome flowers and large fruits (Barring-
tonia speciosUf Calophyllum inophyllum, Cerbera odollam, Guettarda
speciosa, Hernandia peltata, Ochrosia, Pa7idanus, etc.), that line the
beach in a Pacific islet are not to be found on islets in West Indian
waters, where the vegetation bordering the beach is formed of shrubs
and small trees of a very different character. Then, again, we miss
in the Florida sand-keys the tall trees of Canarium, Eugenia, and
Ficus (banyans) that occur in the interior of islets in the Western
Pacific — islets only a few hundred yards in length and heaped up but
two or three feet above the waves. These trees represent the work
of the fruit-pigeons, an agency ever in operation in these seas.

The similarity is greatest in the case of the plants creeping on the
sand, and with the shrubs and small trees with their climbers that
form the outposts of the beach vegetation. Canavalia obtusifolia,
Ipomoea pes-caprce, Sesuvium portulacastrum, and Suriana maritima
occur alike on the Florida sand-keys and on the coral islets of the
Indian and Pacific Oceans. But representative species of the same
genus may play the same role in the different regions. On the
Florida sand-keys and in the Turks Islands bushes of Sccevola plumieri
and Tournefortia gnaphalodes give the same character to the sand-
dunes bordering the beach that is displayed by Sccevola koenigii and
Tournefortia argentea on Keeling Atoll and in the islets of the Western
Pacific.

The differences also extend to the composition of the mangrove
colonies formed on the lee side of the islets. Of the three mangroves,
Bhizophora mangle, Avicennia nitida, and Laguncularia racemosa, on
a Florida sand-key, only the first might be found in the Pacific islet,
though its place would more probably be taken by the Asiatic species,
Rhizophora mucronata. The species of Laguncularia would be repre-
sented in the Pacific by a species of Lumnitzera, an allied genus. The
genus Avicennia would not be present.

If we except the agency of the fruit-pigeon in the Western Pacific,
the currents would seem to be more effective in that region than in
the Florida seas. Practically all the large trees lining the beach in
the Pacific islets owe their presence there to the currents, whilst the
fruit-pigeon has stocked the interior.

APPENDIX

455

Note 8 (p. 131).
The lake of the Grand Etang in Grenada,

Situated in the centre of the island at an elevation of 1800 feet,
this lake is 500 or 600 yards in length, and, as I ascertained by sound-
ing in February 1909, rather under three fathoms in maximum
depth. Since its depth is placed at fourteen feet in the eleventh,
volume of the Encyclopcedia Britannica (ninth edition), a volume
issued in 1880, it is apparent that there has not been much change
in depth in a period of at least thirty years. Exaggerated notions
prevail with regard to the depth, size, and even altitude of this
mountain lake. Although it shallowness has long been known, I
came upon, during my sojourn in the island, many coloured people
who believed it to be unfathomable. Its circumference would
measure barely a mile, yet the lake has been described as over two
miles round and " no less than 3200 feet above the sea " {Stanford's
Compend. Geogr., A. Keane, West Indies, 1901, p. 409).

Its aquatic and subaquatic vegetation calls for a few remarks.
Whilst a water-lily (Nymphcea ampla) occupies the shallows, a dense
swampy belt of tall sedges, chiefly Cladium jamaicense, forms the
borders. Arborescent aroids (Montrichardia arborescens), five or six
feet in height, spring up in the midst of the Cladium belt, which is
fringed at the water's edge by an equisetum-like Scirpus (either planta--
gineus or constrictus). Sclerias of more than one species grow in
abundance among the low trees at the border of the lake; and
clambering over the branches of these trees Dioclea reflexa is fre-
quently to be observed, with occasionally a Mucuna that comes near
M. altissima, DC, as described in Grisebach's pages. [Specimens of
the Cladium from this locality in the herbarium of the Botanic
Garden in Grenada are named CI. jamaicense, Cr., on the authority
of Prof. Urban. In the same collection the Nymphcea from the same
lake is named A^. ampla, DC]

It is considered by Prof. Harrison that the lake of the Grand
Etang probably occupies the place of a former crater. Its shallow
depth, however, is not in favour of this view. If an accurate survey
of the upland region of the island were made it would show that this
shallow lake occupies the expanded head of a valley open to the
north; and as far as the surface configuration is concerned I doubt
if it would be at all suggestive of a crateral origin. I would imagine
that the denuding agencies have re-shaped the central mountainous
portion of the island to such an extent that the present valleys and
mountain profiles have little or no relation with those of the era of
volcanic activity.

The overflow water is carried away by an effluent on the north
side, which, according to the level of the lake, varies between seven
and fourteen feet in breadth and between ten and thirty inches in
depth. If this channel was deepened to the extent of twelve or four-
teen feet the lake would be emptied. During heavy rains the level
of the lake will rise a foot in the course of a night. Thus during one
night of my sojourn, when 2*60 inches of rain feU at the rest-house

456

APPENDIX

near by, the lake's level rose eleven inches. On account of the large
amount of sediment that must be carried into the basin by the
numerous small streams and rivulets that empty into it, the lake is
evidently gradually filling up. Most of these materials are deposited
in the basin, and I should fancy that in a few centuries the lake will
have disappeared. This result will be brought about not merely
through the silting process in the basin, but through the deepening
of the channel of the effluent by its own erosion.

During three days in the middle of February, when the tempera-
ture of the air in the shade at the lake-side ranged between 65*5°
and 73'0° F., that of the water of the lake's surface ranged from
71-8° to 73-7° F., and that of the effluent 71*5° to 72-8° F.

Note 9 (pp. 13, 87, 92).

Guilandina honduc and other species.

Guilandina honduc, though fairly well distributed, is not nearly so
•common in the West Indies as G. honducella. Though both are
httoral species, G. honduc seems to be the species that is most at
home inland. But the questions raised by these two plants, that
often travel around the tropics of the world together, are much
more complex in the New World than in most other regions. Yet
•even in the Pacific islands, as I have shown in my work on Plant
Dispersal, they give rise to several difficulties; but the tendency to
differentiation that they there display is much more marked in the
American continent, and there is ground for the belief that the two
types will admit of being broken up into several smaller specific or
subspecific groups. Urban in his Symholoe Antillance (II., 270-6),
though he does not separate them from the Csesalpinias, describes
eight or nine peculiar West Indian species of the Guilandina type,
usually with yellow or orange-coloured seeds, and mostly from Cuba.
But island groups like the Bahamas, and even the Caymans, may
possess their own peculiar forms, and Millspaugh has described a
new shore species from the last-named locality that stands nearest
to G. honducella (Plantce Utowance).

My inference in the Pacific that seed-buoyancy in Guilandina
goes with station rather than with species, plants of the beach
having buoyant seeds and those from inland seeds that sink, would
not seem to be of general application in the West Indies. Thus on
the beaches of St. Croix I found Guilandina honduc associated with
G. honducella, but only the last had buoyant seeds. Indeed, my
data seem to indicate that in the West Indies seed-buoyancy in
Guilandina goes with species rather than with station. When in
Grenada I tested the buoyancy of the seeds of G. melanosperma, a
variety of G. honduc with black seeds, from Antigua; but they all
sank in sea- water. The lack of buoyancy of the seeds of this species
in the West Indies may be predicated from their rarity in beach-
drift. An indication in the same direction for the genus is afforded
by the fact that in the case of an inland species, apparently un-
described, that I found in the woods on the lower slopes of Mount

APPENDIX

457

Diablo in the heart of Jamaica and 1500 or 1600 feet above the sea,
33 per cent, of the seeds floated in sea-water. All these facts and
inferences for Guilandina in the West Indies invite further inquiry
into the relation between seed-buoyancy and station. Guilandina
bonducella, true to its behaviour in the tropics of the Old World,
possesses typically buoyant seeds. The difficulty of connecting a
littoral station with seed-buoyancy is concerned with G. honduc and
the inland species of the genus.

A few remarks on the station of Guilandina honduc in the West
Indies may here be added. Sloane, writing of the plants of Jamaica
in the latter part of the seventeenth century (Nat. Hist. Jam., II.,
41), states that the Nicker plant with yellow seeds {G. honduc) grew
everywhere in the Jamaican savannahs. I found it associated with
G. bonducella on the beaches of St. Croix; and the two species are
characteristic littoral plants in the Virgin Islands (Harshberger,
Phyt. N. Amer., p. 686). It grows, according to Grisebach, on the
sandy seashore of Antigua.

I raised some young plants of perhaps an undescribed species
from chocolate-brown Guilandina seeds gathered from amongst the
Orinoco drift washed up on the south coast of Trinidad. The seeds
are ovoid but rather compressed, and measure 27 x 20 x 14 mm.,
and float buoyantly. The plants, when eight inches high, had
prickly stems. The leaflets, in three or four pairs, were three to
four inches long, lanceolate or ovato-lanceolate, with a rounded,
rather oblique base, and a long tapering aristate apex.

The species, above mentioned as growing as a stout climber in
young wood 1500 or 1600 feet above the sea on Mount Diablo in
Jamaica, may perhaps be one of Urban' s Cuban species. It was
neither in flower nor in fruit, the seeds (yellow, oblong, 23 x 15 mm.)
of the previous season lying on the ground. The leaflets, in five or
six pairs, were two to three inches long, oblong or obovate, rounded
or subcordate at the slightly oblique base, with usually a tapering
apex terminating in a hair-line point. No stipules observed.

Note 10 (p. 122).

Mucuna pruriens, DC.

The use of the name Mucuna pruriens, DC, as applied to a species
with large globoid seeds, an inch across, which occur in West Indian
beach-drift and are washed up on the shores of Europe, has led to
some confusion. It is not clear how the confusion arose; but two
species have been thus confounded, M. pruriens, DC, an annual and
a weed of cultivation which has been spread by man all around the
tropics, and M. urens, DC, a stout-stemmed, woody climber that
grows on high trees at the borders of forests in the New and in the
Old World and is found also at the coast. The first is known as the
Cow-itch plant, and, as I observed in the West Indies, is common in
land once cultivated, as in abandoned sugar-cane fields. The plant
is a great nuisance when the pods dry and the covering of stinging
hairs comes off. In Tobago it was credited with keeping Indian

458

APPENDIX

coolies out of the island. The second is known in the West and
East Indies as the Horse-eye and Donkey-eye plant, from the peculiar
appearance of the seeds. Its pods have also a covering of stinging
hairs ; but, as the writer knows from a personal experience of both
plants, the irritation produced from this cause is much less than
with the Cow-itch.

It is not often that we can recognise the confusion between the
two species as clearly as we can in the case of a reference to Mucuna
pruriens in the System of Botany, by Le Maout and Decaisne (Engl,
edit., 1873, p. 373). We there read that it is an Indian annual called
Cow-itch, the seed being " called Donkey's Eye, from the large,
pupil-like areola of the testa." Here we have the true M. pruriens
credited with the seeds of M. urens, the seeds of the two species
being, as will be shown below, utterly different in appearance. An
rrror in the reverse direction is sometimes found. Thus Hillebrand,
in his book on the flora of the Hawaiian Islands, after describing the
true M. urens observes that it is " well known as the Cow-itch plant "
and is a native of the West Indies and of tropical America. The
true M. pruriens, which is a pest both for man and beast in old
clearings and abandoned cultivations, is the plant, it may be here
repeated, that is known as Cow-itch.

In his Report on the Botany of the Challenger Expedition (I., 43;
IV., 141, 277, 299) Hemsley applies the name of Mucuna pruriens,
DC, to the Mucuna seeds found in West Indian beach-drift and
washed up on the coasts of Europe. The seed which at the end of
the seventeenth century Sloane recognised amongst the stranded
seeds (Molucca beans) of the Orkney Islands as the " Horse-eye
bean " familiar to him in Jamaica (Phil Trans., XIX., 398, 1695-7)
is identified in this report (IV., 277) as M. pruriens. The two species
are there mentioned under the name of M. pruriens, DC, on
different pages. In the one case, we have a plant " commonly
cultivated and now almost cosmopolitan in the tropics " (IV., 141).
In the other case, it is a plant the seeds of which were found by
Morris in Jamaican beach-drift, and they are described as " some-
times washed ashore on the western coast of Europe " (IV., 299).
As is remarked below, the seeds of M. pruriens proper do not occur
in beach-drift and possess no floating powers.

Yet as a result of the confusion, which probably dates back to the
early part of last century, botanists must have often experienced the
same difficulties. For instance, Ernst in his account of the new
flora of Krakatau (1908, pp. 36, 37, 41, 46) mentions M. pruriens
DC, as amongst the new vegetation that has established itself since
the great eruption on the coasts of the neighbouring island of Ver-
laten, where it climbs on the strand trees. Schimper makes no
reference to such a species in his work on the Indo-Malayan strand
flora, and we can only conjecture that it was not the annual species,
the weed of cultivation, to which this specific name was originally
applied.

It would seem that botanists have been misled by the lack of any
description of the seed of Mucuna pruriens in the works most acces-
sible to them, De Candolle's Prodromus (tome II., 1825) and Grise-

APPENDIX

459

bach's Flora of the British West Indian Islands (1864). Yet, as
pointed out by Sagot, when writing in the Bulletin de la Societe
Botanique de France in 1875 (XXII., 292), the seed was very accu-
rately described by Jacquin in his work on American plants in the
middle of the eighteenth century. It was also described and figured
by Bentham a hundred years after in the Flora Brasiliensis of
Martius (Vol. XV., part 1, p. 169, tab. 46, 1859-62). Both these
works are quoted by Grisebach in connection with the plant, and his
lack of reference to the seed seems unaccountable. Perhaps the
reason may lie in the same doubt that first suggested itself to Sagot ;
that is to say, whether two plants, like M. urens and M. pruriens,
that are associated in the same genus by their floral characters,
would possess seeds so different. Grisebach, with Jacquin's and
Bentham' s volumes by his side, says nothing of the seed of either
species.

The difference in appearance between the large, globoid, iron-grey
seeds of Mucuna urens and the small, sub-reniform, mottled brown,
shining seeds of M. pruriens is well brought out in Bentham's figures.
The first are thick-shelled, an inch across, and nearly surrounded by
the black raphe. The second, which the present writer compares
with ordinary Phaseolus seeds and Sagot with small haricots, are
relatively thin-shelled, barely half an inch in length, and possess a
large scar but no circular raphe. The seeds of M. urens, again,
possess great buoyancy. Those of M. pruriens, as my experiments
indicate, possess none. The first are distributed unharmed by the
ocean currents. The second have evidently been dispersed by man
along trade routes. The first are characteristic of beach-drift in the
West Indies and elsewhere. The second have never been recorded
from beach-drift, nor are they at all likely to occur there.

For a long while I clung to the use of the name of Mucuna pruriens
as applied to a species with seeds of the M. urens type, since its
employment was backed by high authorities. However, when I
included seeds of this type under the name in a collection of West
Indian drift sent to the Natural History Museum in 1912, Dr. Rendle
kindly pointed out that they were not those of M. pruriens, which
were much smaller and more oblong in form, and that they were
probably those of M. urens. This decided the matter. In the
treatment of the drift seeds of Mucuna in other parts of this work
it is pointed out that there are two kinds of seeds of the urens type
dispersed by currents; and the specific name of " pruriens " was in
the above-named collection applied by me to the seeds which are
now designated in these pages as " near urens, seeds that may be
those of M, altissima, DC, a matter discussed on p. 120.

Note 11 (p. 60).

The relation between the floras of Ascension and St. Helena and the

currents.

As we learn from Hemsley {Chall. Bot., III., 32-4), we have no
positive proof that more than two of the flowering plants of Ascen-

460

APPENDIX

sion are really indigenous, namely, Hedyotis adscensionis and Euphorbia
origanoides, both of which are endemic. The first is more nearly
related to African and Asiatic species than it is to the St. Helena,
H. arbor ea. The second has its nearest ally in E. trinervia from the
Guinea coast, there being no indigenous species of Euphorbia in
St. Helena. Current-borne seeds could only reach Ascension through
the agency of the Main Equatorial Current, which would carry drift
to it from tropical Africa and from the extra-tropical southern
part of the continent, the South African Current here coming into
play.

St. Helena, lying as it does in the track of the South Equatorial
Current, which is fed by the off-shore waters of the South African
Current, would not receive any African drift except from the southern
extremity of the continent ; but through the intermediate agency of
the South Atlantic Connecting Current it would be the recipient of
drift from the South American region gathered by the Brazil Current
between Cape St. Roque and the River Plate. It would be quite
cut off by the currents from Ascension and could receive no drift
from the north, Dr. White's contention that the flora and fauna
arrived from the north in the direction of the Cape Verde Islands
being quite untenable (quoted by Scharff, p. 388). If the currents
have been concerned in stocking the island, they would have brought
to it seeds from South Brazil and the River Plate as well as from
the Cape. It is noteworthy that whilst Hooker finds the most
characteristic affinities of the flora in southern extra-tropical Africa,
Hemsley, following Bentham, points to equal or closer affinities
between its arboreous Compositae and South American types (Ibid.,

m., 59).

Though there is no evidence that the plants concerned are dis-
tributed by the currents, it is remarkable that this agency, if effec-
tive, might possibly explain in both Ascension and St. Helena the
affinities determined by the botanists. Yet from the endemism of
the genera with South American affinities, it may be inferred in the
case of St. Helena that whilst the South American connection is
largely a thing of the past, that with South Africa has been main-
tained up to relatively recent times. (The system of currents pre-
vailing in the South Atlantic is discussed in Chapter III. and Note 18.)

Note 12 (pp. 51-55).

Bottle-drift on the Azores,

The answer to the question as to the source of the vegetable drift
stranded on the Azores is plainly given in the results tabulated below
for bottle-drift. All the seeds stranded there must come from the
west, namely, from the coasts of the New World between Newfound-
land and the West Indies. Nothing comes from the eastward, and
it will subsequently be shown that bottles dropped into the sea in
the vicinity of this group either display the same easterly drift or are
carried south into the North Equatorial Current, ultimately reaching
the West Indies. This conclusion applies to all seasons of the year,

APPENDIX

461

the lack of data in the American charts for the summer months
being supplied in Schott's memoir.

All of the twenty-seven bottles dealt with in this table came from
the region between Sable Island off the Nova Scotian coast and
Cuba, but the number for each locality is no indication of relative
frequency, since most of the experiments were begun in the north.
It is noteworthy that none of these bottles approach the group from
the southward, all from the quarter between West and North-north-
west— a fact brought out in the cases of those dropped into the sea in
mid-ocean to the westward of the islands. To the southward and
westward lies a debateable region from which, according to the
compiler of the American charts, but few bottles are ever recovered,
though " crossed by numerous sailing and steamship routes and
within which in all probability are cast as many bottle papers as in
other portions of the ocean." This region lies between the main
drifts of the Gulf Stream and North Equatorial Current, and, accord-
ing to the same authority, is confined between 25° and 40° N. lat.
and 30° and 60° W. long. But even if we curtail these limits a little,
since bottles can reach the Azores from the same parallel a few
hundred miles to the west, the fact remains that in this part of the
central Atlantic there is interposed between the Azores and the
New World to the south-west the vast area of the Sargasso Sea,
covering some 120,000 square miles, where, as Laughton (p. 221)
observes, collects a very large proportion of the drift or wreckage
which floats about the Atlantic. This may explain why four and even
six years may elapse before some of the bottles are recovered on the
Azores. Indeed, the progress of drift to the Azores seems to be
never rapid. Of the rates given for nineteen bottles not one reaches
ten miles a day. Though those drifted there from the vicinity of
Cape Hatteras seem to travel at the same speed as those that are
carried to Europe from the same locality, the passage from the
Nova Scotian region is very tedious, bottles taking rather longer for
the drift from that region than they do from Cape Hatteras, although
the distance is much less.

The fate of other bottles thrown into the sea in the vicinity of the
Azores, between 60 and 150 miles east and west of the group, is
illustrated in Dr. Schott's paper. Of four, one was recovered on the
coast of Norway, and the others, after being carried south, were
transported by the North Equatorial Current to the West Indies,
being found on the Bahamas, on one of the northern islands of the
Lesser Antilles, and on the north-west coast of Cuba.

It would seem, therefore, that whilst the islands of the Azores can
only receive drift from the coasts of North America and from the
West Indies, they can supply it to the coasts of Europe and to the
West Indian region.

The Prince of Monaco's observations in 1885 and 1887 to the
N.N.W. and N.W. of the Azores at distances of 200 to 800 miles,
largely confirm the results above given, in the case of bottles thrown
overboard 200 to 750 miles W. and N.N.W. of the group. Of eleven
floats that reached there from distances between 280 and 460 miles
N.N.W. of the islands, the three most rapid drifts gives a mean of

462

APPENDIX

6*9 miles a day (7*7, 7*3, 5*7). Of twenty-six floats thrown over be-
tween the Azores and the Great Bank of Newfoundland, the five
most rapid drifts give a mean daily rate of 5*3 miles.

Tablb Illustrating the Localities from which Bottlb-dbift
reaches the azores

(The averages for the time occupied in the drift and for the daily rate are estimated
from the shortest periods elapsing between the dates of the start and recovery of the
bottle, as given in the last column. Most of the data are from the American charts,
the remainder are from Schott's memoir, but all the daily rates are based on the
former, the details of the references being given on p. 47).

Number

of
Bottles

Distance

Averages

Shortest
Drifts in Miles
per Day

Starting-place

in

Nautical
Miles

Days

Miles per
Day

South of Cape Sable and Sable
Island between 38° and 43° N.
lat

8

1500

294

5-1

5-6; 4-5 (A)

Off Cape Hatteras within a
radius of 300 or 350 miles .

8

2400

273

8-8

9-9; 7-7 (B)

Off the E. coast of Florida .

1

Off the N.W. coast of Cuba

1

3180

435

7-3

To the westward of the Azores,
200-750 miles W.-N.N.W. .

9

400

71

5-6

6-4; 4-8 (C)

27

(A) Drift-rates for 6 bottles.

(B) „ „ „ 8 „

(C) „ „ „ 5 „

Note 13 (pp. 56-58).
Bottle-drift in the Turks Islands,

The Turks Islands, with the neighbouring Caicos Islands and the
two Inaguas, have received a large amount of bottle-drift. We
learn from the Rev. J. H. Pusey's Handbook (1897) of these islands
that bottles are " constantly being picked up by the natives."
During my sojourn in the Turks Group in 1911 I found that the
coloured people had lost their interest in returning the enclosed
records, since no money was forthcoming. Fortunately plenty of
material is at my disposal for determining the directions from which
bottle-drift reaches this region, and also the direction it takes when
it passes the islands to places beyond. Below will be found data for
thirty-three bottles which were recovered in these islands, and for
forty bottles which were dropped into the sea in the middle of the
channel between the Turks Islands and the Hispaniola coast.

We see there that three bottles reached here from the vicinity of
the Azores; one from off the south-west of Ireland; one from off

APPENDIX

463

Lisbon; fourteen from the region included in the Madeira, Canary,
and Cape Verde Groups; two from mid- Atlantic to the eastward;
eight from a few hundred miles N.-E.N.E. of the Turks Islands;
three from between Bermuda and the Bahamas; and one from off
Cape Hatteras. But this list of localities should be supplemented
from the data supplied by bottles that passed between the Turks,
Caicos, and Inagua Islands and were recovered on the Bahamas
farther west, as well as on the north coast of Cuba. The Bahamian
islands receive bottle-drift not only from the localities above named,
but also from the eastern side of the Lesser Antilles and from the
shores of the Guianas and North Brazil. The Antillean Current,
referred to in Chapter III., would be instrumental in this direction,
and a good instance is there mentioned of a bottle which was stranded
in the middle Bahamas after being thrown into the Main Equatorial
Current between St. Paul's Rocks and Cape St. Roque.

All the bottles that reach the south-eastern Bahamas from the ,
eastern side of the North Atlantic have followed the track of the
North Equatorial Current to the West Indies; and where, as often
happens, they have started as far south as the Cape Verde Islands,
they cross the Atlantic well south of the 20th parallel and arrive at
the Turks Group after brushing the coasts of the northern islands of
the Lesser Antilles. A glance at the map will show that in the last
case the drift approaches the Turks Islands from E.S.E., and that
these islands receive the drift which in the Antillean Current has
traversed the Lesser Antilles between Porto Rico and Guadeloupe.
The tracks of several bottles, as laid down in the American charts,
directly indicate that much drift from the south-east, which would
otherwise have arrived at the south-eastern end of the Bahamas,
has been intercepted by Porto Rico, the Virgin Islands, St. Thomas,
and other islands in that region.

Just as suggestive of the prevailing direction taken by drift, when
traversing the south-eastern Bahamas, are the results given a page
or two later for a large number of bottles dropped into the sea between
the Turks Islands and Hispaniola. Out of forty all were carried to
the westward, and nearly all entered the passage between Cuba and
the Bahamas leading to the Florida Strait. Though most of them
were stranded on the way, usually on the Cuban side, three passed
through and reached the straits. Of these, two got no farther and
were beached on the coast of Cuba; but one was caught in the
swift current of the Gulf Stream, and after a drift across the Atlantic
was recovered 337 days afterwards on the west coast of Ireland.
This westward trend of the bottle-drift after passing between
the Turks Islands and Hispaniola is the effect of the Antillean
Stream.

The conclusion to be drawn from all these bottle-drift data is very
significant of the direction of the drift traversing the south-eastern
Bahamas. There is a prevailing set in a W.N.W. direction towards
the Florida Strait; but although much of the drift is stranded on
the way a certain proportion reaches the straits, and some of it gets
within the influence of the Gulf Stream. The indications are, there-
fore, that the Turks Islands lie in the track of drift on its way in the

464

APPENDIX

Antillean Stream to the Florida Strait from regions to the eastward
and southward.

But in the winter months, when the North-east Trade blows freshest
and is often very northerly, these islands are also the recipient of
drift from the northward and eastward, probably mostly material
that would otherwise have passed to the eastward of the Turks
Group, but is thrown back on the beaches by the strong " northers "
that are not infrequent in this season. During the winter bottle-
drift may even arrive at these islands from the vicinity of Bermuda.
Dr. Schott (p. 13) in this connection observes that the N.W. direction
of the drift in the seas between the Bahamian and Bermudian Islands
is not always illustrated by the bottle -drift, and he gives a case where
a bottle thrown over early in February about 150 miles S.S.W. of
the Bermudas was recovered on the Turks Group forty-nine days
later, the distance covered being 542 miles.

I will first give the data concerning bottles stranded on the islands
forming the south-eastern extremity of the Bahamas, namely, the
Turks and Caicos Islands and the two Inaguas. They are mainly
supplied in the American charts and in Dr. Schott's paper; but a
few are taken from the Nautical Magazine for 1852. The following
is a grouping of the materials according to their starting-places.

Sources of bottle-drift found on the south-eastern islands of the

Bahamas,

A. Vicinity of the Azores within a radius of 400

miles

B. Off the south-west coast of Ireland, 260

miles distant

C. Off the coast of Portugal, near Lisbon, 50

miles from land

D. In the vicinity of Madeira and the Canary

Islands within a radius of 160 miles .

E. About 120 miles off Cape Blanco and half-

way between the Canary and Cape Verde
Islands

F. In the vicinity of the Cape Verde Islands

within a radius of 250 miles to the north,
south, and west

G. In mid-ocean, 1000 to 1500 miles E.-E.S.E.

of the Turks Islands

H. Between 100 and 350 miles N.-E.N.E. of

the Turks Islands between December and
March

I. Between Bermuda and the Bahamas during

January and February

J. Off Cape Hatteras

3 bottles (9 %)
1 „ (3 %)

1 » (3 %)
(18 %)

(3 %)

7 „ (21 %)

2 „ (6 %)

(25 %)

3 „ (9 %)
1 . (3 %)

33

(100 %)

APPENDIX

465

The above list, as already implied, does not exhaust the sources
of the bottle-drift stranded on the south-eastern Bahamas. On
the islands of the same group, farther to the north-west, have been
recovered bottles dropped into the sea off the east side of the Lesser
Antilles and off the coasts of the Guianas and of North Brazil,
which, as they were borne along in the Antillean Stream, must have
passed between the Turks, Caicos, and Inagua Islands, to reach their
destinations.

The subjoined notes refer to the results above given : —

A. The average distance by Madeira and the Cape Verde Islands
route would be about 4200 miles, the greatest daily rate indicated
being 7-2 miles.

B. Recovered after 597 days, giving a minimum daily rate of 8-5
miles over a distance of 5100 miles (see Note 20).

C. D, E, F. Except in two cases only the tracks on the chart are given.
In one of them a belated drift of only 3-5 miles a day was indicated.
In the other, which is given in Purdy's Columbian Navigator for
1839, a bottle from off Madeira was found ten years afterw^ards
on the Turks Islands.

G. The fastest daily rate up to the time of recovery was 5-3
miles.

H, I. All were stranded during the winter months, a season when
the Trade may blow strongly for long spells from the north. The
number of bottles thrown over a few hundred miles to the northward
and eastward give an excessive idea of the relative frequency of
drift from this quarter, since the captains of one or two ships seem
to have been especially interested in this point. At this season,
also, drift may arrive from the vicinity of the Bermudas.

J. Recovered after 309 days. It probably accompUshed a short
circuit of the North Atlantic by being deflected south in the neigh-
bourhood of the Azores. Several bottles thrown over at the same
time reached the shores of Europe (see p. 49).

Equally suggestive, as significant of the direction pursued by
floating drift in this region, are the indications of bottles dropped
overboard in the seas between the south-eastern Bahamas and His-
paniola. In the American charts are given the data for forty bottles
thrown over between October and May just half-way between the
Turks Islands and the coast of Hispaniola in or about 20° 30' N. and
71° 30' W., and about forty miles S.S.W. of the Turks Group. They
were mostly cast over from the S.S. New York in 1906; but some
were thrown over from the S.S. Cherokee in 1905, besides one or
two from other vessels. There was evidently a special reason for
selecting this locality, which on account of the number of bottles
thrown over there, probably some hundreds, if we allow for the non-
recoveries, must be nearly un ique in the West Indian region. Doubt-
less it was concerned with the investigation of the Antillean Stream,
which is the current that traverses this region on its way northward
and westward towards the Florida Strait. The results of these
experiments are now given.

H H

466

APPENDIX

>Places of recovery of forty bottles cast overboard about half-way
between the Turks Islands and the adjacent coast of Hispaniola.

A. North coast of Cuba 29 bottles

B. Middle and north-west Bahamas . . . 7 ,,

C. Jamaica and the Cayman Islands . . . 2

D. Yucatan 1

E. Ireland 1 „

40

A. Most of them were stranded on the north-east coasts of Cuba,
but two or three were carried farther and thrown ashore on the Cuban
side of the Florida Straits. The average daily drift rate indicated
was not over eight or nine miles.

B. The average drift was five or six miles a day.

D. Stranded on or near Cozumel Island : daily drift 9-6 miles.

E. Recovered on the coast of County Mayo 337 days afterwards,
giving a daily drift rate over 4140 miles of 12-3 miles (see Note 20).

Note 14 (p. 49-54).
The bottle-drift of the Bermudas.

(Materials mainly supplied by the American charts, but also by the papers of
Dr. Schott and the Prince of Monaco.)

As regards its relation to the circulatory system of currents in
the North Atlantic, Bermuda may be viewed as situated near the
inner end of an eccentric spiral, of which the outer end may be
considered as represented by the Gulf Stream, as it rushes through
the Florida Strait, and the terminal portion as represented by
the Antillean Stream curving northward and eastward from the
region dividing it from the Bahamas. On the face of things, there-
fore, we should expect that these islands would receive much and
impart but little.

I have at my disposal the records of about forty bottles, recovered
on these islands, which ought to supply sufficient materials for a
preliminary inquiry into the subject; but it will be necessary to
make at first a brief reference to the implications involved in such
an investigation. As regards the Bermudian fauna and flora opinion
seems to fluctuate between two schools of thought : the older school
typified in the views of Wallace, Hemsley, and others, who consider
that the islands have been stocked through the agencies of birds and
currents, and the newer school typified in the views of Dr. Scharff
and others, who see in the Bermudian indigenous plants and animals
the remains of an ancient fauna and flora which this region received
when joined to the North American continent ( Scharff' s Distribution
and Origin of Life in America, pp. 183-95).

As far as the starting-places indicate, bottle-drift may reach the
Bermudas from all points of the compass. Bottles have arrived there

APPENDIX

467

from off the Nova Scotian coast due north of the group (one) ; from
between the Azores and the Great Bank of Newfoundland (three) ; from
the Eastern Atlantic opposite the Bay of Biscay in about longitude 18°
W. (two) ; from the Eastern Atlantic in the latitude of the Canary
Islands, but about 800 miles further west (one) ; from mid- Atlantic
between the parallels of 20°-23° N. and the meridians of 40°-50' W.,
within the northern border of the North Equatorial Current (three) ;
from Florida coasts and from Cuban seas (three); from off the
continental coasts to the westward in the region of Cape Hatteras
(fifteen); and from a number of directions all around the group
in the case of bottles dropped overboard in the vicinity. The possibi-
lities of Bermuda as a gathering-place for drift are great when we
regard the area of the region indicated by the starting-places of the
bottles that have been thrown up on its shores. Such a region
would comprise the breadth of the North Atlantic from coast to
coast between the 20th and 50th parallels of latitude. Although
the possible starting-place might lie anywhere at the borders of this
region, the point of approach would be nearly always from the w^est,
the range varying usually between north-west and south-west.

This brings one to remark that the Bermudas occupy a singular
position with regard to the two principal currents that could supply
them with drift — the Gulf Stream from the New World and the North
Equatorial Current from the old World. It receives what is played
off from the borders of one current and what is brought to it by a
connecting stream from the other.

As regards the Gulf Stream, it receives the " tailings " of the current
as it proceeds northward to Cape Hatteras and is gradually deflected
eastward towards Europe. This is well shown when we compare
the daily rates of bottle- drift reaching Bermuda from the Cape
Hatteras region with those for bottles reaching Europe from the same
locality. Thrown overboard within a radius of 250 or 300 miles
from Cape Hatteras, which would include the main stream of the
current, bottles are carried to Europe, a passage of over 3000 miles,
at an average rate of eight to nine miles a day, whilst the passage
of 500 or 600 miles to Bermuda is accomplished at an average rate
of rather over five miles a day. The American charts supply data
for fifteen bottles that reached Bermuda from the Hatteras region.
The quickest minimum rate of 5-4 miles a day was attained in two
cases, whilst the three bottles next in speed gave rates of 5-3, 5-3,
and 5-1 miles. The consistency in the five fastest rates enable one to
largely eliminate the effects of delay in the recovery of the bottles.
The contrast between the slow drifting rate to Bermuda and the fast
drifting rate to Europe is well illustrated by a set of five bottles that
were thrown over together from the S.S. Cherokee about a hundred
miles north of Cape Hatteras, the particulars of which are given
in Chapter III. Two bottles recovered on the Bermudas gave
minimum daily rates of 3-1 and five miles, whilst those picked up on
the Scottish coast, on the Shetlands, and near the North Cape of
Norway, gave minimum rates of 7-8, 6-9, and 10-2 miles respectively.
The playing off of drift from the outer border of the Gulf Stream
towards the Bermudas is probably continued as the current heads

468

APPENDIX

towards Nova Scotia after passing Hatteras. That the process
begins soon after the current emerges from the Florida Strait is
indicated below.

West Indian vegetable-drift, as is well known, is thrown up on
the Bermudas in quantity; but the indications of bottle-drift are
that it would be usually belated. Vegetable- drift reaching the
islands from this region would hail from the seas between South
Florida, Cuba, and the Bahamas and from the coasts around. In
most cases, however, there would seem to be great delay, and it
is evident from the behaviour of bottle- drift that it may be carried
around the North Atlantic before it is stranded on the Bermudian
coasts. There is the case of a bottle that was recovered in Bermuda
nearly three and a half years after it had been dropped into the
sea, in February 1902, between Key West and the Cuban coast
(Amer. chart, Febr. 1909). There is another case of a bottle that
after being dropped over near Key West, in October 1901, was picked
up on Bermuda five and three-quarter years afterwards (Amer.
chart, Oct. 1908). Then we have a bottle which was found on Ber-
muda 466 days after it had been cast into the sea about 200 miles
to the northward of Great Abaco (N.W. Bahamas), though the direct
passage across the sea was barely 600 miles (Amer. chart, Febr.
1909). But that the passage of West Indian drift to these islands
may at times be fairly rapid is illustrated by a bottle that was re-
covered in Bermuda seventy-three days after it had been cast over-
board in the northern part of the Florida Strait, the passage of 900
miles having been accomplished at a minimum daily rate of rather
over twelve miles (Amer. chart, Nov. 1908). The behaviour of
this bottle indicates that the tailing off of drift from the Gulf Stream
towards Bermuda may begin soon after the current issues from the
Florida Strait.

From the data above given, as far as they go, it may be inferred that
West Indian seed-drift may reach the Bermudas in the following
ways. It may be deflected eastward from the Gulf Stream soon
after the current issues from the Florida Strait, when the passage
would occupy two or three months. This deflection may not take
place until the current passes Cape Hatteras, when the time occupied
would be five or six months. The drift may be carried past the
Bermudas in the Gulf Stream and accomplish the circuit of the
North Atlantic, returning in the North Equatorial Current, which
would cover three years. Drift from the north-west Bahamas would
probably only reach Bermuda by getting within the influence of
the Gulf Stream farther north, a tedious process that is illustrated
by one of the bottles.

With the North Equatorial Current, the carrier of drift from the
Old W^orld, the Bermudas are connected by means of the Antillean
Stream (see Chapter III.), as is explained by Schott (p. 13). But
probably they would only receive in this way the drift in the slack
waters of the North Equatorial Current north of the 20th parallel.
In the American chart (May 1909) the track is given of a bottle,
thrown over in mid- Atlantic" in lat. 22° 54' N. and long. 39° 42' W.,
which accomplished a passage computed at 2430 miles at the mini-

APPENDIX

469

mum rate of 7-8 miles a day. In the same charts, but for December
1908, there is a track of a belated bottle which reached Bermuda
from a position about 600 miles further west on the 22nd parallel.
In both these cases allowance is made for the northward curve of
the Antillean Stream towards Bermuda, which the bottles approach
from the south-west. The same plan is followed by Schott in laying
down the tracks of bottles reaching Bermuda after traversing the
Atlantic in the North Equatorial Current, though he gives the
Antillean curve a greater sweep and makes them approach the
islands from the west. According to this chart one such bottle
which was thrown into the sea about the 28th parallel and about
800 miles west of the Canaries was picked up at sea nearly 200 miles
N.E. of Bermuda.

But two bottles have been stranded on these islands which were
cast into the sea in the eastern Atlantic only 400 or 450 miles north-
west of Cape Finisterre. On their way south in the Portuguese
or North African Current they would pass near Madeira and the
Canary Islands before coming within the influence of the North
Equatorial Current, and the whole passage of about 4300 miles
would probably occupy about two years. No details are given
either by Dr. Schott or by the Prince of Monaco, from whose pages
these two records are taken ; but from the data for similar traverses
given in Chapter III. we should probably be not far wrong, if, after
allowing for the delay in reaching and leaving the North Equatorial
Current, we placed it at about six miles a day. In Dr. Schott' s
example we can determine the approximate position of the starting-
place (46° N. 19° W.) from his map; but in that of the Prince of
Monaco we can only say that it was one of a large number of floats
that were dropped over in 1886 along the 18th meridian of west
longitude and between the parallels of 42° 30' and 50° N.

Still more interesting are the records of three floats thrown over
in the Prince of Monaco's observations of 1887 between the Azores
and the Great Bank of Newfoundland, as well as to the north of
that group. They form 2 per cent, of the recoveries, and taking
the Prince's general estimate of such drifts at 6-4 miles a day, the
passage of about 5000 miles implied would occupy about twenty-six
months, and would almost involve the circuit of the North Atlantic
by way of the Portuguese and North Equatorial Currents. An
approach yet nearer to the completion of this circuit is concerned
with a bottle thrown over about 130 miles to the south-east of Cape
Sable (Nova Scotia) and recovered in Bermuda 1602 days afterwards.
In the American chart (Dec. 1908) the passage is computed at
5880 miles, which gives a minimum rate of only 3-7 miles a day, and
the compiler characterises it as " almost completing the circuit
of the ocean." It is noteworthy that although this bottle was
cast over about 580 miles north of Bermuda, its passage to those
islands involved a distance tenfold in amount. This well iUustrates
the peculiar position of Bermuda with regard to the currents of the
North Atlantic. It is in the track of none of them, yet at the end
of all of them.

This brings one to notice another feature in the relation of these

470

APPENDIX

islands to the North Atlantic currents. Whilst they may receive
drift from all round this ocean, they do not figure often as distributors
of drift to distant regions. The records of bottle-drift at my disposal
for the North Atlantic number some hundreds; but there is only
one record of any distant region having received drift from the
vicinity of the Bermudas. They give nothing to the adjacent
coasts of America only a few hundred miles away. Bottles thrown
into the sea -^-ithin a day's steaming from their shores usually find
their way back to the islands sooner or later, even if years elapse.
I have the records of seven bottles dropped in the seas around
Bermuda, to the north, south-east, south-west, west, and north-west,
at distances ranging between 200 and 350 miles. Five out of them
were recovered on the islands ; but only in one case is a rapid passage
indicated; and here a bottle was recovered twenty-five days after
it had been dropped overboard about 300 miles to the south-east
of the group. Of the other four, one from 240 miles to the north
was found seven months afterwards ; another from 300 miles W.N. W.
was picked up also after seven months; another from 350 miles to
the west was recovered after nearly six months; and the last from
200 miles to the south-west was not found on the islands until two
years had passed. It does not, therefore, seem easy for drift to
leave the Bermudas, since at most if it obtained an offing it would
be caught in the baffling play of the currents around the islands and
would be returned after an interval perhaps of months or years.
The behaviour of bottle-drift in Bermudian waters was evidently
a source of difficulty with Schott, who remarks (p. 13) on the numerous
examples from this region concerning which it is scarcely possible
to determine their tracks.

Yet under certain conditions it might be possible for the Bermudas
to establish a connection \y\th. the Bahamas. But apparently it
would be only in the winter months, when the North-east Trade
blows freshest and blows home in these seas, that such a connection
would be practicable — a matter mentioned in the treatment of the
bottle-drift of the Turks Islands in Note 13. Schott (p. 13) gives
an instance of a bottle, which, dropped over about 150 miles S.S.W.
of Bermuda, early in February, was picked up on the Turks Islands,
at the extremity of the Bahamas, forty-nine days later. He quotes
the ship's log to the effect that at the time of the start the conditions
of wind and current were unfavourable for any drifting passage to the
Turks Islands ; but with this exception we know nothing of the actual
conditions experienced by the bottle in this remarkable drift. The
possibility, however, of the passage of drift from Bermudian seas to the
Bahamas is illustrated in the preceding note on the Turks Islands.
It is there shoT\Ti that many bottles reach the south-east Bahamas
during the winter months from the northward and eastward, the
longest drift being accomplished by bottles from within 300 miles
of Bermuda. Here I may mention the tracks of five others, referred
to in the American charts for the \^'inter months from November
to March, where the bottles reached San Domingo and the central
and north-west Bahamas from about half-way between Bermuda
and the Bahamas.

APPENDIX

471

Occasionally, again, a bottle breaks away altogether from the
eddies of the Bermudian seas and reaches the opposite coasts of
the Atlantic ; but it starts from the Gulf Stream side of the islands
200 miles to the westward, and would represent the track not of
Bermudian but of West Indian and American drift. Thus in the
American chart for February 1909 the track is given of a bottle
that was recovered on the Orkney Islands fourteen months after
it had been thrown over about 200 miles W.N.W. of Bermuda.

Viewing the group as the recipient rather than as the distributor
of drift, it is curious to notice how many localities on the opposite
coasts of the North Atlantic would supply it with these materials.
Though well outside the tropics, it figures as regards vegetation
mainly as an outlier of tropical lands to the south and west. It is
in that direction that we must chiefly look for results of effective
dispersal by currents. The current that brings it seed-drift from
that quarter would derive it from Cuban and Florida seas, as well
as from the continental shores brushed by it as far north as Cape
Hatteras ; but for the most part the Cuban and Florida drift would
be alone effective. The currents that brought bottle-drift from a
few hundred miles off Cape Finisterre sweep past the coasts of Morocco
and the islands of Madeira and the Canaries, and would doubtless
bring seed-drift from those localities, which, however, would be
mostly ineffective for the purpose of dispersal, since a passage of
one and a half and two years would be involved. Strange but
useless gifts might arrive from the shores of Nova Scotia and New-
foundland after a circuit of the North Atlantic covering about three
years.

The Bermudas would be practically cut off from South America
and from the regions from which the Main Equatorial Current
derives its drift. I have no record of any bottle reaching these-
islands from equatorial regions or from the South Atlantic. There
is, however, a possible connection through the Antillean Stream;-
but the drift which that current supplies to Bermuda would be
the drift it receives at its eastern border from the northern portion
of the North Equatorial Current, and not the drift that its main
stream at times brings to the Bahamas from the coasts and rivers
of the Guianas and Brazil. Bottle-drift from the South American
localities just named may, as we have seen in Chapter III., reach
the Florida seas ; but I have found no record of its having ever been
recovered on the Bermudas. Still, the possibility remains.

Note 15 (p. 51).

The circuit of the North Atlantic accomplished by drift.

It would not be possible in the case of bottle-drift to be absolutely
certain that one and the same bottle had accomplished this circuit,
since evidence such as is supplied by derelicts of the position at
different stages of the passage would not be forthcoming. The
chances, however, of its having happened often are very great.
Its antecedent possibility is proved over and over again in piece-

472

APPENDIX

meal fashion in the bottle-drift charts. For instance, the traverse
from the West Indies to the coasts of Europe by the Gulf Stream
route and back again in the North Equatorial Current in tropical
latitudes is there many times illustrated. Several bottles have
performed the greater part of the circuit. Thus, one from the Cape
Verde Islands which reached the coast of Ireland must have taken
the West Indian route (see p. 59). Then, again, we get cases of this
Itind. Bottles have been found on the Turks Islands from off the
Irish coast, and on the west coast of Ireland from the vicinity of the
Turks Islands (Note 20) ; the route in the first case being by the Cape
Terde Islands and the North Equatorial Current, and in the second
by the Straits of Florida and the Gulf Stream. An assumption that
the circuit of the North Atlantic has been almost accomplished is
justified where bottles have been thro'VMi over in the vicinity of the
Nova Scotian coast and are found four years after on a Bermudian
beach (see Note 14).

The circulatory movement of the waters in the North Atlantic
was established by the Prince of Monaco's extensive experiments,
as discussed in Chapter III.; but since his field of observation did
not extend to the western part of the ocean his conclusion was mainly
based on the drifting of his floats from positions north-west and east
of the Azores to the West Indies, the western portion of the circuit
being assumed, according to common knowledge, to be the work
of the Gulf Stream. The nearest approach to the completion of
the circuit by a single float was displayed in three cases, where his
floats thrown over to the north-west of the Azores were subsequently
recovered on the Bermudas.

The principal delay in the circuit of the North Atlantic would
take place in the eastern portion of the ocean in the passage south
from European waters to the zone of the North Equatorial Current
in the vicinity of the Cape Verde Islands. This is indicated in the
table in Chapter III. dealing with the drifting rates of bottles ; and
it is well brought out in the circular drift of the derelict Alma
Cummings from off Cape Hatteras to Panama, where drifting
rates of sixteen or seventeen miles a day characterised the Atlantic
traverses in the Gulf Stream and in the North Equatorial Current
and a rate of only four miles a day in the passage of the intervening
zone (Schott). The track of the Alma Cummings is described
by Schott (p. 13, map 1) from materials given in the Nautical
Magazine for 1896. Since its positions were fixed during its passage
and the date of its beaching on the coast of the Panama Isthmus
was known, the estimate that it accomplished a passage of 5320
jniles at the average rate of ten miles a day is well founded.

Note 16 (p. 50).

Traverse of the North Atlantic by the derelict " W. L. White.''

An interesting record is supplied in the case of the dereUct schooner
W. L. White, which was drifted to the Hebrides from Baltimore

APPENDIX

473

Bay (about 240 miles north of Cape Hatteras) in rather over ten
months (315 days). Dr. Schott, who gives the data in his memoir
(p. 10, map 1), obtained them from the supplementary pilot chart
of the North Atlantic for February 1889 (U.S. Hydr. Office). From
the several positions determined during its passage it is apparent
that about five months were occupied in drifting about within an
area a few hundred miles across to the eastward of Newfoundland.
Had it not been for this interruption the traverse of the ocean would
have been accomplished within six months. After the first two
months the vessel was water-logged and was entirely under the
influence of the current. In the first half of the traverse, before
the decks were awash, the average daily rate was sixteen miles;
but the last 550 miles were covered at ten miles a day. The general
track of the derelict may be placed at about 3200 miles, which gives
an average daily rate of ten miles on her course from Baltimore
Bay (March 13, 1888) to the Hebrides (Jan. 23, 1889).

Note 17 (p. 447)
Mr. Lloyd Praegefs experiment on seed-huoyancy.

In a paper entitled " The Buoyancy of the Seeds of some Britannic
Plants," which was published in the Scientific Proceedings of the
Royal Dublin Society for 1913, Mr. Lloyd Praeger gives the results
of by far the most extensive series of experiments hitherto made
in this inquiry. He gives his own results for 786 species of flowering
plants, and supplementing them with those obtained by others
for plants not experimented on by himself he supplies the data for
just 900 British plants. I may be pardoned for adding that the
results, to use the author's own words, fully bear out the conclusion
formed by me as the outcome of an earlier series of experiments that
" the buoyant-seeded plants in our flora are in the main inhabitants
of either riverside or seashore " (p. 49).

This investigator also improved on the methods of his predecessors
as far as direct experiment is concerned. The discrepancies between
his own results and mine may be due, as he remarks, partly to the
variable behaviour of the plants themselves and partly to different
conditions of experiment. Of the first kind he gives some striking
examples. His results also support the conclusion first formed by
Darwin, and confirmed by those who followed him, that the great
majority of seeds possess little or no floating power, probably not
less than 90 per cent.

Unfortunately space does not allow me to do more here than to
refer to these very important investigations; but I may remark
that my results were also based on prolonged observations on the
floating seed-drift of ponds and rivers. A combination of the two
methods may remove some of the difficulties. Any young naturalist
eager to take the subject up would find opened up for him a very
interesting field of inquiry, and a very good guide in the paper of
Mr. Lloyd Praeger.

474

APPENDIX

Note 18 (p. 60).

The differentiation of the Main and South Equatorial Currents in

mid-Atlantic,

I will here deal with the indications that in mid- Atlantic the Main
Equatorial and South Equatorial Currents can be differentiated,
and that they are separate but contiguous currents. They are
afforded by six bottles that were dropped into the sea at different
times in the vicinity of the island of Ascension, the data for which,
supplied in five cases by Schott and in one case from the Nautical
Magazine, are given in the table below. They were cast over in
three cases on the north side of Ascension and in the other three
on the south side at distances varying between 50 and 350 miles
from the island. The southernmost, thrown over in 11° 38' S.
lat., was stranded on the coast of North Brazil (2° 40' S. lat.) ; the
others being recovered in three cases on Trinidad, one on the Grena-
dines, and one on the south-east coast of Jamaica. All these bottles,
even the southernmost, were borne along in the Main Equatorial
Current, none of them being carried south of Cape St. Roque. The
first three were solitary bottles that were thrown over in different
months and different years. The last three were thrown over on
three successive days from a ship proceeding north-west on the
track between St. Helena and Ascension, and they require particular
attention in this connection.

The first thrown over about half-way between the two islands in
lat, 11° 38' S. was stranded at Paranahiba on the north coast of
Brazil in lat. 2° 40' S. The second starting from a position nearer
Ascension in lat. 10° 4' S., reached the Grenadines in the Lesser
Antilles in lat. 12° 42' N. The third cast over in lat. 8° 39' S. and
about fifty miles south-east of Ascension was recovered near Morant
Bay on the south-east coast of Jamaica in lat. 17° 56' N. The
implication is that bottles thrown over in the Main Equatorial
Current in the vicinity of Ascension reach the West Indies; whilst
those thrown into the same current half-way between St. Helena
and Ascension reach the coast of Brazil north of Cape St. Roque,
which divides the Main and South Equatorial Currents. From this
we should expect that if from the same ship bottles had been cast
over near St. Helena they would have been carried south when
approaching Cape St. Roque in the southern current. From this
point of view Ascension would be regarded as within the zone of
the Main Equatorial Current and St. Helena as in the track of the
South Equatorial Current.

This is what was meant by the differentiation of these two equatorial
currents in mid-Atlantic, the drift of the main stream ultimately
getting into the Guiana Current and that of the southern stream
into the Brazilian Current. This distinction acquires importance
when we come to consider the current connections of Ascension and
St. Helena. From this standpoint they would be quite isolated
as far as direct communication by currents is concerned. Such
a view is supported by data supplied by a bottle which after being

APPENDIX

475

thrown into the Indian Ocean off the coast of Natal was recovered
at Alcobaco in Brazil in lat. 17° 30' S. It was held by Dr. Schott
(pp. 19, 27, map 4) that the track of this bottle probably lay near
St. Helena. Fuller details of this interesting drift have been given
on p. 63.

Data relating to Bottles thrown over in the vicinity of Ascension
(7° 56' S. Lat. ; 14° 22' W. Long.)

Starting-place

Time when

Place of
Recovery

No.

Distance in

S.
Lat.

W.
Long.

thrown over-
board

of

days

Miles and
Daily Rate

Remarks

1

2

3° 30'

6° 2'

15° 0'
15° 6'

May
January

Trinidad
Trinidad

—
192

3000 at
15 6 per
day

4017 at

18-1 per

day
3264 at

11-7 per

day
1977 at

11-3 per

day

Schott, map 2, No.
318; position ap-
proximate

Nautical Magazine,
1852, No. 45

3
4

5

r 30'

8* 39'
10^4'

13° 0'
13° 50'
11° 55'

September

February 23,
1875

[February 22,
1875

Trinidad

Jamaica
(Morant
Bay)
Grenadines

222
280

Schott, map 3, No.
333 ; position ap-
proximate
Schott, p. 27, map
1, No. 302

Schott, p. 27, map
1, No. 301

6

11° 38'

9° 5'

February 21,
1875

Paranahiba,
N. Brazil,
lat. 2° 40' S.

175

i

Schott, p. 27, No. 3

i

Note. — Nos. 6, 5, 4, were dropped over from the ship Schwan on three successive
days.

Note 19 (p. 59).

The Guinea Current,

In the region between 2° S. and 10° N. lat. and 20° and 32° W. long.,
where the Guinea Current flows east between the North and Main
Equatorial Currents, lies an area of conflicting streams, a subject
which is discussed in detail by Dr. Schott (p. 17). A bottle thrown
over in its centre in May would be cast up on the coasts of Africa;
whilst if dropped over in October it would be carried to the West
Indies. The effect of the shifting boundaries of these currents is
well illustrated in the vicinity of St. Paul's Rocks in the south-west
corner of this region. Here in certain months of the year it would be
difficult to predict whether the bottle would drift to the east or to
the west. A striking example is supplied by Schott in the case of
two bottles thrown overboard together on February 24, 1893, in
lat. 1° 44' N. and long. 27° 16' W. (pp. 10, 18, map 1). One was
recovered on the coast of Sierra Leone on September 8 of the same
year, and the other on the Nicaraguan coast on March 8 of the following
year.

The Guinea Current must often carry back to the African coasts

476

APPENDIX

drift that it has captured from the two equatorial currents. This
would be especially the case, as pointed out by Schott (p. 17), with
the drift of the southern current. But the important feature is
that the Guinea Current during the northern summer extends much
farther west than in winter. During a portion of the year this current
is restricted mainly to the eastern half of the Atlantic ; but it may
at other times extend to the vicinity of the South American and
West Indian region and assume the role of a true counter-equatorial
stream. The extension westward and the withdrawal eastward of
this current greatly affects the drifting direction of bottles thrown
overboard in the area above described. Schott carefully worked
out this point, and from his results, elaborated on page 17 of
his memoir, it appears that we have the real explanation why bottles
dropped into the sea in this area at the same place in different seasons
arrive in one case at the American and in another at the African side
of the ocean.

Whilst the varying behaviour of the bottles as indicated by Schott
would limit the extension and retreat of the Guinea Current within
the meridians 22° and 32° W., the actual extension westward may
be much greater. We learn from the Admiralty publication {Africa
Pilot, Part I., 1907, p. 49), that its western limit can be traced at
all seasons of the year as far as the 23rd meridian (W. long.), but that
in the summer and autumn months an easterly current extends as
far west as the 53rd meridian. " This is probably " (as the writer
proceeds to remark) " an expansion of the Guinea Current proper,
or a counter-equatorial current." Laughton (p. 225) is representative
of those who treat the counter-equatorial current as a thing apart
from, the Guinea current. It may be that the difference in view
is only concerned with a difference in names. The Admiralty view
that the first is a summer and autumn extension of the second is
directly stated in Captain Jackson's Winds and Currents (p. 26,
1904).

It is in its character as a counter-equatorial stream that the Guinea
Current attracts the interest of the student of the trans-oceanic
distribution of seeds in this part of the Atlantic. We are wont to
consider that through the agencies of the two equatorial streams
Africa figures only as the giver and the West Indian and tropical
American region as the recipient in the process of distribution of
seeds by currents in these warm latitudes. But here we have pre-
sented the possibility of a reversal of the operation, when Africa
becomes the borrower from the New World. On account of the
great predominance of the westerly drift currents in these seas the
indications of the floating bottle would as a rule illustrate only
the transference of drift from the African to the American side of the
Atlantic. But occasionally the track of a bottle from the American
to the African side breaks through this routine. Thus in Schott's
first map there is the course laid down of a bottle (No. 425) which
was recovered on the coast of Sierra Leone after being cast overboard
in March about 270 miles N.E. of Cape St. Roque, and less than a
hundred miles north of the island of Fernando Noronha, the approxi-
mate position being in about 2° S. lat. and 32° W. long. Its track

APPENDIX

47T

has the appearance of lying athwart the stream of the South Equa-
torial Current; but since the 32nd meridian in March represents
the westerly limit from which, according to Schott's tabulated
results (p. 17), bottle-drift reaches the African coast, we have here
evidently the result of the extended Guinea Current acting as a
true counter-current across the breadth of the Atlantic. At such a
time the counter-stream might readily capture some of the vegetable
drift washed off the coasts of North Brazil.

There is thus a possibility that at certain seasons seeds may be
transported from this part of the South American sea-border to
the shores of Sierra Leone and Liberia. It is here that the South
American and African continents make the nearest approach, only
about 1550 miles separating Cape St. Roque from the nearest point
of Africa. It is only a possibility, and, although the event may be
of very rare occurrence, it cannot be ignored.

Note 20 (p. 72).

Bottle-drift from the South-east Bahama seas to the coast of Ireland

and hack.

The following two bottles performed between them the circuit
of the North Atlantic, the track of the first being by the Straits of
Florida and the Gulf Stream route, that of the second by the North
African and North Equatorial Currents.

(a) Thrown over in April 1906, in the channel between the Turks
Islands and the Haitian coast. Recovered 337 days afterwards
on the west coast of Ireland (lat. 53° 45' N.), having covered 4140
miles at the minimum rate of 12*3 miles a day (see Note 13). The
details are given under Bottle 59 in the U.S. chart of the North
Atlantic for May 1909.

(6) Thrown over in January 1900, about 260 miles to the west
of the south-west coast of Ireland in lat. 51° 15' N. and long. 17°
16' W. Recovered after 597 days on the Caicos Islands at the
south-eastern end of the Bahamas, having covered 5100 miles at
the minimum daily rate of 8*5 miles. The details are supplied in
the U.S. chart of the North Atlantic for December 1908.

Note 21 (p. 85).

On some small-seeded West Indian littoral plants.

Brief reference may here first be made to the group of four small-
seeded littoral West Indian plants, Sesuvium portulacastrum, Portu-
laca oleracea, Herpestis monniera, and Heliotr opium curassavicum,
that are generally distributed in the tropical and subtropical regions
of the globe — the two first being characteristic of the sandy beach,
the third of marshy ground, and the last often of saline mud around
lagoons. In all cases the seeds possess little or no buoyancy, and
doubtless much of the cosmopolitan range of each of these plants
is due to the agency of the drifting log bearing the seeds in its crevices.

478

APPENDIX

to the unintentional assistance of aboriginal man in his long canoe
voyages, and to birds. They came under my notice on almost every
coast I visited in warm regions, whether insular or continental. To
discuss the various interesting points raised by these plants would
be to travel beyond the limits assigned to this work. Not the
least important is the presence in some regions side by side with
these cosmopolitan plants of peculiar species of the genus. Thus,
both the Hawaiian and West Indian Islands have in each case
peculiar species of Portulaca. That men and animals have been
active factors in the dissemination of some of these plants in inland
regions is very evident. Thus, Portulaca oleracea is not only a plant
of the sandy beach, but it grows in waste ground away from the sea.
There was a story told, I believe, by the late Sir Joseph Hooker,
relating to a botanist, who, on landing on one of the uninhabited
islands of the Southern Ocean that had never been explored, fell
on the sand with his face in the midst of a patch of Portulaca oleracea.

The above list could be much extended if we added plants not
quite so widely spread. Thus, to take the case of Cor chorus hirsutus^
a typical West Indian shore shrub, also found on the east coast
of Africa and in Australia. Its seeds are about 1*5 mm. in size,
and the species owes its wide distribution over the warm regions
of the globe doubtless to a variety of agencies human and otherwise.
Then there are the salt-loving herbaceous plants that are widely
distributed in the New World growing on the mud-flats bordering
lagoons and coastal swamps, such as Salicornia ambigua and Batis
maritima. Although, as is shown in my book on Plant Dispersal
in the cases of other species of Salicornia and in that of Batis maritima^
these plants are especially well fitted for dispersal by currents,
since the seeds germinate in sea-water and the floating seedlings
there thrive, it is obvious that considerations other than those
concerning means of dispersal are here presented to us. Salicornia
is a genus distributed over the greater part of the globe, and Batis,
which holds only a single species, is restricted to the New World.
Batis maritima has been recently introduced into the Hawaiian
Islands, having been first found by Hillebrand in a small island off
Honolulu in 1859, and no doubt its introduction was due to human
agency.

Note 22 (p. 343).

The Azores and their African connections as illustrated by Sphagnum,

One of the most useful features in Warnstorf's monograph on the
Sphagnacece is a list of all the known species of Sphagnum grouped
according to the floral regions. It often happens that the student
of distribution has to make such a list for himself; but here he finds
reference made easy; and the amount of time thus saved is very
considerable. But the method has its disadvantages, since much
explanatory material is needed to safeguard the student against
pitfalls ; and perhaps it would be wisest in the absence of such matter
to employ such a list with caution when drawing general inferences.
A case in point is represented in this work. At the end of the list

APPENDIX

479

of African species (p. 35) it is pointed out that the majority of them
are endemic, the only exceptions being ten species that are there
named. But unless the student goes through the whole list, there
is nothing to indicate, what is actually the fact, that seven of these
species are not known from the African continent at all, and only come
into the list as components of the Sphagnum flora of the Azores,
a group of islands placed here under Africa. All the seven species
range widely over the globe, and their inclusion as African would
thoroughly change the character of the Sphagnum flora of the con-
tinent, especially as concerning its external connections, Africa
being almost a closed region as far as the Peat-mosses are concerned.
With respect to Sphagnum, the Azores are plainly a part of the
European region, there being no African affinity, and no North
American connections except such as are also European.

Note 23 (p. 38).

Pumice on the beaches of the Azores.

Pumice is washed up in quantities on Azorean beaches, but
doubtless it is almost all of local origin. On the north coast of San
Miguel it is very abundant, being evidently brought down in the rainy
season by streams from the inland districts. Pumice-tuffs often
predominate in the interior, and as a result of their disintegration
pumice is strewn over great areas of the surface. The pumice is
evidently andesitic, being naturally darkish in colour but presenting
a light-coloured, weathered exterior. The fragments are as a rule
very buoyant when freshly removed from the tuffs, and no doubt
would float for years. (In one of my experiments in the Solomon
Islands, referred to in my book on the geology of that group, andesitic
pumice pebbles originally gathered in the tow-net at sea remained
afloat after two and three-quarter years.) In time, however, pumice
lying exposed on the surface in wet localities loses its buoyancy.
Thus I found that after being exposed for a long period on the scantily
vegetated higher slopes of Pico da Vara in San Miguel, where the
rainfall is great, the pumice fragments had become sodden and
no longer floated. On the shores of Lake Furnas in the centre of
the island they may be seen in a well-rounded state, due to attrition
during prolonged flotation in its waters. In that state they are
carried down by the effluent streams to the sea. It is therefore
necessary to remember that pumice may begin its trans-oceanic
voyage in a well-worn condition.

Note 24 (p. 377).

Trailing growth of Anagallis tenella.

A singular variation in growth was displayed in an experiment
made in South Devon some years ago. The typical plants are
usually described as possessing creeping stems a few inches long
(three or four inches). However, in the spring of 1906 I noticed

480

APPENDIX

growing in a large pot containing a shrub some young plants of this
species. I had been in the habit of mixing Sphagnum with soil
for potting purposes, and evidently the plant had been introduced
in this way in the previous autumn. As the soil-conditions were
very much drier than those of the boggy ground in which the species
normally grows, I resolved to note their effect on the young plants
in question.

During the summer of 1906 they developed a trailing habit, the
main stems, seven inches long with secondary leafy shoots two inches
in length, hanging over the sides of the pot. Through the winter
they remained in the same leafy state, and in the spring rapid growth
took place, so that by July 1907 the main stems were seventeen
inches in length (three inches in the pot and fourteen inches hanging
over), the secondary shoots or branches being proportionately long.
Flowering now occurred, and the pot draped all around with the
hanging stems formed quite a pretty spectacle. It remained thus
until the autumn, when I went abroad and the experiment ended.
The experiment was repeated in November 1912, when I put some
other plants in an ordinary pot of soil and kept them in the same
conditions as before. After flowering in midsummer the plants
began to trail over the sides of the pot, producing stems about six
inches long. When in the Azores, I watched carefully on the moors
for evidence of this trailing habit, but only found a tendency in this
direction in the case of plants growing in drier conditions on the sides
of banks.

The leaves in these experiments were much larger than with the
typical growth, 7x6 mm. instead of 3 x 2*5 mm. The usual
winter leaf of the normal plant is particularly small, 2 to 3 mm.;
whilst the summer leaf is as a rule markedly larger; but I found
that this is only indirectly due to the season. In November of two
different years I noticed that the typical small leaves were produced
when the plant lay flat on the oozy mud or on a level patch of boggy
ground, which would be usual in winter. In places, however, where
the plants were creeping over loose-growing Sphagnum or clambering
over stocks of Carices, under circumstances where the lower leaf-
surfaces were freely exposed to the air, the size of the leaf was
increased to between 4 and 6 mm.

The interesting point in these observations is that the plants in
the first experiment assumed the habit of growth of Anagallis filifor-
mis (Ch. and Schl.), where the stems attain a length of eight inches
(20 cm.). This is a peculiar extra-tropical South American species
growing in sandy and moist places in South Brazil (Primulacece by
Pax and Knuth, Pflanzenreich, 1905). Although at first regarded
as a distinct species of the Tenella group of the genus, it is viewed
in De Candolle's Prodromus as only a variety of Anagallis tenella ;
and it is noteworthy that the species just named is not known either
from South or from North America. The essential differences are
slight, and are chiefly concerned with the degree of woolliness of the
filaments and with the extent of the adhesion in their lower part.
The stamens of the flowers were especially examined only in the
second experiment, and displayed the characters of those of A.

APPENDIX

481

tenella. In this species, as we learn from Pax and Knuth, the fila-
ments are woolly along most of their length, and they unite to form
a free tube one-third of their length. In A. filiforrnis the filaments
are only woolly below their middle, and their cohesion concerns
but a fourth or fifth of their length.

Should any botanist in South Brazil be kind enough to send me
specimens of Anagallis filiformis both in flower and in mature seed,
I could try the effect of growing the plant under the conditions of
an English peat-bog.

Note 25 (p. 76).

Sabine's record of the drifting of casks of palm oil from the
Gulf of Guinea to Hammerfest.

Sir Edward Sabine in one of the notes appended to his English
edition of Humboldt's Kosmos (Vol. I., note 373, p. 454, 1846) gives
particulars of a remarkable case of drift from the Gulf of Guinea to
the vicinity of the North Cape, which naturally attracted the attention
of Gumprecht, Fogh, Vibe, and others who have written on the
subject. As evidence that portions of the cargoes of vessels wrecked
on the coast of West Africa may reach Norway after making a double
traverse of the Atlantic in the Main Equatorial Current to the West
Indies and in the Gulf Stream to Europe, Sabine writes as follows :
" Such an instance occurred when the Editor was at Hammerfest,
near the North Cape of Europe, in 1823; casks of palm oil were
thrown on shore belonging to a vessel which had been wrecked at
Cape Lopez, on the African coast, near the Equator, under circum-
stances which made her loss the subject of discussion when the
Editor was in that quarter of the globe, the year preceding his
visit to Hammerfest." The matter is also mentioned by Lady
Sabine in her translation of Humboldt's Ansichten der Natur (Vol. I.,
p. 161, 1849).

I have not found any fuller details of this wonderful drift, which
is properly characterised by Gumprecht as the most interesting
recorded fact, and by Fogh as sufficiently marvellous. These casks
would have taken the course by the West Indies indicated by Sabine,
and the only question arising in this respect is whether they reached the
starting-place of the Gulf Stream in the Florida seas by way of the
Caribbean Sea and the Gulf of Mexico, or in the Antillean Current
skirting the northern and eastern shores of the Lesser Antilles.
From the evidence given in Chapter III. the former course is most
probable. The circumstance that not a single cask only but " casks "
are stated to have been washed ashore at the same place, and appar-
ently about the same time, after a drifting passage of from 10,000
to 11,000 miles, discloses the first point for criticism. For reasons
given in Chapter III. it is highly improbable that casks could keep
together during a double traverse of the ocean, for which a period
of at least two years would be needed.

According to the tables given in Chapter III. the time occupied
would be about twenty-six months by the Caribbean Sea route and
about twenty-four months by the Antillean Stream route. Com-

482

APPENDIX

mander Campbell Hepworth's estimate for the first route, as quoted
below, is at least thirty months. But Sabine's record would seem
to suggest a period of only about a year, which involves an average
drifting rate of from twenty-seven to thirty miles a day for the whole
distance. Much depends, however, on the exact dates. If the
interval between his visit to West Africa in 1822 and his sojourn
at Hammerfest in 1823 covered the period between the early part
of one year and the latter part of the other year, the objection against
the excessive drifting rate would be to some degree removed. There
remains, however, the question of the identity of the casks.

In this difficulty I applied to Commander Campbell Hepworth,
Marine Superintendent of the Meteorological Office, one of our
leading authorities in matters connected with the Gulf Stream, and
he very kindly gave me the following reply : " It is possible that
casks of oil could be preserved long enough to drift to the north of
Norway, but they would be so covered with barnacles, etc., that
they w^ould be unrecognisable. By a somewhat careful calculation
I find that the drift would occupy at least 900 days, say, two and a
half years." Then he proceeded to point out that the track would
follow the course in the Equatorial Current via the Gulf of Mexico
to the Strait of Florida, and subsequently northward and eastward
to the Grand Banks, then through the Iceland-Faroe Channel to
the north coast of Norway. I may add here that the possibility
of this drift is increased by the behaviour of a bottle mentioned in
the follomng note, which thrown into the sea close to the island of
Ascension was recovered afloat off the coasts of Guernsey ; but here
a difficulty also arises, though it is concerned not with the identity
of the drifting object, but with a possible confusion of dates, the
genuineness of the actual drift being viewed as outside dispute.

Note 26 (p. 76).

A bottle-drift from Ascension to Guernsey.

Major Rennell in his work on the Currents of the Atlantic, and
Commander Becher in the Nautical Magazine for 1852 and 1854,
refer to a bottle which on October 15, 1820, was thrown overboard
about two and a half leagues north-east of Ascension from the Ameri-
can vessel Lady Montague. It was picked up afloat off the western
coasts of Guernsey on August 6, 1821, after an interval of 295 days.
On these points both authors agree, and Rennell adds that notice
was sent to the Admiralty. He rightly terms it "a remarkable
instance," and assigns to it the route via the Caribbean Sea and by the
Gulf Stream. But here we meet the same difficulty that was pre-
sented by Sabine's casks of palm oil referred to in the previous
note. To accomplish this passage of some 9000 miles between these
dates a drifting rate of about thirty miles a day is needed. In this
connection it is possible that there has been some confusion in the
dates. Rennell refers incidentally to a record of the Pique, as though
there was another similar record; and whilst the starting-point
given by him is in 7° 55' S. and 14° 23' W., the position assigned

APPENDIX

483

in the Nautical Magazine for 1852 is 7° 7' S. and 8° 6' W., which is
quite inconsistent with the statement associated that the bottle
was cast over two and a half leagues north-east of Ascension. It
is unfortunate that, as with Sabine's remarkable case of drift, there
is here the suspicion of a doubt, which in neither case, however,
affects the possibihty of the passage, though in the one it is concerned
with the identity of the casks and in the other with the dates assigned
for the start and recovery of the bottle.

Note 27 (p. 38).
Bottle-drift on the Canary Islands.

From what has been said in Chapters II. and III. it will be gathered
that the Canary Group lies in the track of that portion of the seed-
drift of the Gulf Stream which, after passing north of the Azores
and approaching the European sea-border, is deflected south in the
Portuguese or North African Current. Losing much of its materials
on the shores of South-western Europe and on the coast of Morocco,
the bulk of the residue traverses the Canaries, and continuing south
turns westward near the latitude of the Cape Verde Group, finally
reaching the West Indian region in the North Equatorial Current.
All the records supplied by bottles and floats would therefore be
expected to come from the north and north-west. The data to be
now given indicate that this is actually the case, there being no
records from the south. (The materials are supplied from the Ameri-
can charts, the Prince of Monaco's papers. Dr. Schott's monograph,
the Nautical Magazine, etc.)

Of the twenty-eight bottle-drift records at my disposal, one came
from the vicinity of Cape Sable (Nova Scotia), sixteen from the
region between the Azores and the Banks of Newfoundland, one
from off Cape Farewell (Greenland), and ten from the seas north of
the Canaries, between the meridians of 13° and 18° W., and at dis-
tances ranging from 500 to 1200 miles north of the group (37°-49° N).
Though there is no record of a bottle or float from West Indian
waters, several of the floats dropped over by the Prince of Monaco
between the Azores and the Banks of Newfoundland must have
begun their drifting passage in the middle of the track pursued by
West Indian seeds across the North Atlantic ; and doubtless instances
of stranding on the Canaries would have been forthcoming with
more extensive data at one's disposal.

The daily rate of the drift from the North-west Atlantic to these
islands is evidently small. Of 996 floats thrown over in 1887 by
the Prince of Monaco between the Azores and the Great Bank of
Newfoundland (including sixty-five from positions to the north of
the Azores), 142 were recovered, and of these fourteen (10 per cent.)
were found on the Canary Islands. The mean daily drift of the
five recovered in the shortest time is placed by him at 5*32 miles.
If we place the average distance traversed at about 2000 miles,
about a year (376 days) would be covered in the passage. A period
of only six months between the times of the start and recovery is

484

APPENDIX

implied in the Nautical Magazine for 1852 in the case of a bottle
(No. 102) thrown over in November 1835 about forty miles south
of Cape Sable (Nova Scotia), and picked up in May 1836 on the island
of Fuerte Ventura (Canaries). The distance traversed would not be
less than 3600 miles, which gives a daily rate of about twenty miles,
an estimate that is very excessive for the traverse of this part of
the North Atlantic, and it is likely that there has been a printer's
error here, as affecting the dates.

One of the most interesting of the records for the Canary Islands
is given by Rennell in his work on the Currents of the Atlantic.
When in command of H.M.S. Hekia in lat. 58° 13' N. and long.
46° 55' W., about 140 miles S.W. of Cape Farewell (Greenland),
Captain Parry threw over a bottle, which rather over two years
afterwards (June 16, 1819, to July 29, 1821) was recovered on
Teneriffe. This is evidently the " enigmatical drift " (rathselhafte
Trift) to which Dr. Schott, quoting the Physical Atlas of Berghaus
(1837), alludes in his paper (p. 1). It does not, however, appear
to be quite so mysterious when we reflect that four bottles thrown
over by Captains Parry and Ross in Davis Strait, 1818 to 1821,
between 59° and 65° 40' N. lat., w^ere found between eight and fourteen
months afterwards floating off and stranded upon the coasts of North-
west Ireland, West Scotland, and the Outer Hebrides. All of them
must have got into the main track of the Gulf Stream, and we have
seen in the earlier chapters of this work that Gulf Stream drift may
be stranded anywhere on the coasts of Europe between the North
Cape of Norway and Morocco, and that no inconsiderable portion
of it may be returned by the way of Madeira and the Canaries to
the West Indies. If, therefore, drift can reach the Irish and Scottish
coasts from Davis Strait, the passage of drift from Cape Farewell to
Teneriffe would be quite probable (see Note 35).

Note 28 (p. 38).

The bottle-drift of Madeira.

All that has been said in the previous note of the Canary Islands
might be expected to apply to the neighbouring islands of Madeira,
which lies in the course of the same North African or Portuguese
Current — a current representing the southerly deflection of the great
North Atlantic easterly surface-currents that bear the Gulf Stream
seed-drift to Europe. Like the larger islands of the Canaries, Madeira
is ill-adapted for receiving and holding bottle-drift, and the records
are scanty. But they are sufficient to show that we have here the
same story of drift from the North-west Atlantic and from the seas
in European latitudes to the north of the island, none coming from
the south.

The Prince of Monaco gives six records for floats that were reco^ ered
in Madeira after being dropped overboard in 1885 and 1887 in the
region between the Azores and the Banks of Newfoundland. In
the American charts there is the record of a bottle (October 1908,
No. 4) which reached Madeira from a position about 400 miles due

APPENDIX

485

north of the large islands of the Western Azores. With reference
to bottles arriving from European latitudes to the north of Madeira,
Schott gives a record (No. 24, map 2) and the American charts
give another (March 1909, No. 98). Here the bottles reached the
island after being cast over 300 to 360 miles N.N.E. The average
daily rate for this part of the Atlantic would be about five miles.
It is highly probable that West Indian drift after traversing the
Atlantic in the Gulf Stream track is at times diverted to Madeira ;
but the records of bottle-drift at my disposal are too scanty to afford
a direct indication of this fact.

Note 29 (p. 38).
Sargasso or Gulf weed in Azorean beach-drift.

The Sargasso weed is only represented by scattered fragments
more or less incrusted with polyzoa. Gulf weed seems to be rarely
carried eastward of the group except in this condition. Captain
Ostboe of the fruit- steamer Fix, who had accomplished about eighty
voyages between London and Hamburg and the Azores, told the
writer that he had never seen living patches of Sargasso, such as
are met with a few hundred miles to the south-west of the islands.
Authorities vary somewhat in placing the north-east limit of the
Sargasso Sea. All, however, place it to the southward and west-
ward of the group, and if we regard the nearest approach as 250
or 300 miles south-west of Flores we shall probably be near the
limit. It is possible that during south-west gales the living weed
may reach the islands, but I found no fragment that did not indicate
a prolonged flotation of months in the dead state. The south-east
trend of the currents would under ordinary circumstances only
permit its approach from the north-west far beyond the area where
the living weed is found.

It would, indeed, appear probable that the fragments of dead
Sargasso which reach the Azores have accompanied the drifting
West Indian seeds in their circuitous passage from the Florida seas
past Cape Hatteras, as described in Chapter III. Sargasso weed
seems to possess a fugitive vitality outside its usual waters.
Rennell in his work on the Currents of the Atlantic Ocean (p. 183)
refers to the observations of Lieutenant Evans, who contrasts the
great masses of living weed that were met with in the Gulf of Mexico
with the old brown patches of the weed covered with " barnacles "
observed in the Florida Stream.

Walker in his book on the Azores (p. 47) speaks of quantities of
Sargasso weed being washed ashore at certain seasons of the year
on Graciosa, the islanders employing it for fertihsing the land. It
is likely that this is not the true Sargasso, but another weed altogether.
The people of Magdalena at the west end of Pico, give the name,
as the present writer ascertained, to quite another sea-weed that
was washed up in abundance during the heavy north-west gales
that prevailed during his sojourn there in March. Like the Graciosa
men they use it for enriching the soil. They are familiar with the

486

APPENDIX

true Sargasso, but they call it " Plante do Golfe " (Gulf weed). The
other weed evidently grows around the coasts, and is torn off by the
breakers in heavy weather. In this connection it may be noted that
fragments of true Sargasso have been found on the coasts of Cornwall
and on the Shetland beaches, probably in the dead state.

Note 30 (p. 210).
Iguanas, snakes, and alligators, in the Turks Islands,

It is probable, that iguanas, snakes, and alHgators were all of them
frequent in these islands before their occupation by white men.
The iguanas have been exterminated on all but two or three of the
islands. The snakes are now confined to a single cay. The alligators
have disappeared, and as their presence would not have been welcome
on such small islands they were doubtless effectually destroyed.
There can be no difficulty in explaining the existence of snakes and
alligators on these islands, since San Domingo lies only about a
hundred miles distant from the southernmost cay.

Large snakes and crocodiles are known to have been transported
alive across far broader tracts of sea. For instance, they have
reached Keeling Atoll that lies 700 miles from land in the Indian
Ocean. When on the atoll in 1888 I was told of three or four living
snakes and of a living crocodile that had been stranded there on
drift-wood some years before. (See my paper on Keeling Atoll in the
Journal of the Victoria Institute of London, 1889.) That this attempt
on the part of nature to re-stock the atoll with snakes and crocodiles
is always going on is evidenced by the remarks of Wood- Jones, who
was on the Keeling Islands in 1905. He refers to the preservation
in the Governor's house of the skulls of two crocodiles that had been
shot on the atoll after arriving in this fashion. Many snakes must
have reached the islands since my visit, clinging as he says, to floating
drift. " There are several instances " (he writes) " of large snakes
having been killed in the atoll, and others have been picked upon
the beach " (Coral and Atolls, 1910, p. 295).

There must be several records of this kind relating to the West Indian
region. Purdy in The Columbian Navigator (1839, III., 31) makes
the following interesting note : " Some years back a very large cedar
came on shore at Sable or Sandy Bay (St. Vincent), bringing with it
a large female hoa constrictor, which took to the neighbouring wood,
and when shot, some days after, was found to contain many young
ones, nearly ready to escape; and which, but for the destruction
of the old one, would have taken up their abode in the woods."
I may add that large snakes of this description exist on the island
of Tobago about 100 miles away; but it would seem most likely
that it arrived at St. Vincent with Orinoco drift, and in that case
the distance traversed in the swift equatorial current would have
been about 300 miles.

The following notes are taken from my journal in the Turks Islands.
Although the large iguanas evidently once existed on all the islands
of this small group, they seem now (1911) to be principally, if not

APPENDIX

487

entirely, restricted to the uninhabited islands of Long Cay and Greater
Sand Cay. In the last named they are particularly abundant, in
spite of the fact that numbers are captured by fishing parties of the
coloured natives from Salt Cay and Grand Turk that from time to
time make a brief sojourn there. The fruits of Genipa clusiifolia
(Seven-year Apple) are evidently appreciated by these reptiles;
and it is remarked, when dealing with this plant, that the two islands
now frequented by them are just those where the Seven-year Apple
grows in greatest quantity. Reference has already been made
(p. 277) to the allusion to the iguanas of the Turks Islands in the
Annual Register of 1764 (Watkins). As a change from salt-pork,
we are told that the flesh of these creatures was much prized by the
early Bermudian salt-rakers. Iguanas formed a staple article of
diet of Bahamians in Catesby's time, about 1725 (II., 64) ; and they
are still appreciated by the coloured people of the Turks Islands.
We brought back with us to Grand Turk from Greater Sand Cay
a number of iguanas alive in a sack; and I learned that they are
often transported to Grand Turk and Salt Cay from the islands in
which they abound. Not improbably the Caribs did the same
when carrying provisions for their voyages ; and it is not unlikely
that they intentionally stocked with these reptiles some of the
isolated cays of the Bahamian seas which served as resting-places
during their passages.

The existence of a large snake on Eastern Cay was reported to
me by several persons famiHar with that island; but it did not
come under my notice during my two visits in February 1911.
Alligators are not now known to exist in the group ; but about two
years before my stay there a dead aUigator was found on a beach
in Cotton Cay partially buried in the sand. The postmaster, Mr.
Lea Smith, whose brother had made the discovery, informed me that
it was probably washed ashore in a dead or dying condition. These
reptiles would even now find congenial surroundings in the mangrove
swamps of South Creek in Grand Turk ; and it is more than probable
that they originally infested these islands, having been exterminated
by the inhabitants.

Note 31 (p. 408).
Draccena draco (Dragon-tree).

This interesting tree, which is confined to the Canaries, the Madeiras,
and the Cape Verde Islands, though in the last two nearly or quite
extinct, specially attracted my attention on Teneriffe, as I had been
previously familiar with Draccena aurea, the peculiar Hawaiian
species, which is the only representative of the genus in Polynesia.
Of the forty species distributed over the warmer parts of the Old
World, these two on account of their restricted range are amongst
the first to draw the attention of the student of distribution.

Whilst still well represented in the Canaries, favouring, as Dr.
Christ remarks, the steep sides of the rocky ravines and gorges as
they descend to the coast, it seems to be almost extinct in Madeira.
In fact, it is stated that Webb a couple of generations ago saw the

488

APPENDIX

last Madeiran plant. Yet Lowe in his Manual of the Madeiran
flora (1857) includes it amongst the very rare indigenous plants.
In the Cape Verde Islands it was recorded only from St. Antonio,
but as a cultivated plant, by Schmidt in the middle of last century
(Flora der Cap Verdischen Inseln, 1852). However, Hemsley in
Science Progress for 1894 (Vol. II.) states that it is still said to exist
here and there in the mountains of St. Antonio and St. Nicolas.
But it is not named by Prof. Coutinho in the list of the plants
of the islands in his Catalogus Herbarii Gorgonei Universitatis
Olisiponensis, Lisbon, 1914-15. It may be added that although
the tree is not a native of the Azores, it is to be occasionally observed
in gardens as on Pico and on San Miguel.

In addition to the numerous solitary specimens of the Dragon-
tree planted in and near towns on Teneriffe, I came upon it in 1906
growing wild on the Taganana coast near the north-east extremity
of the island. Here in the company of the cactoid Euphorbia {E.
canariensis) it grows on the faces of rocky declivities in inaccessible
parts of the precipitous slopes of the Roque de las Animas, a pinnacle
mountain rising 1400 or 1500 feet above the sea. Though growing
singly, there were several trees scattered about on the mountain-side
in situations suggestive of dispersal of the seeds by birds. Its station
may be compared with that of the Hawaiian DraccEua aurea, which
is not uncommon in the open wooded districts up to 3000 feet, but
grows in a variety of situations. Thus, I found it once in the broken-
down caverns of an old lava-flow frequented by pigeons that doubtless
brought the seeds.

Hillebrand gives no affinities for the Hawaiian species; but Sir
Joseph Hooker has some very suggestive reflections on Draccena
draco in one of the appendices of his book on Marocco and the Great
AtlaSy where the Canarian flora is discussed (pp. 410, 417). It has,
he says, " only one near ally, D. ombet, which is confined to Abyssinia,
Southern Arabia, and the intervening island of Socotra." He suggests
the hypothesis that at a very remote period this Draccena, together
with the tropical trees of Myrsinece, Lauriiiece, etc., that belong to
the Canarian flora, flourished in the area included in North-west
Africa and its adjacent islands, and that they have been expelled
from the continent by altered conditions of climate. In this connec-
tion he also links with the Draccena the Sapotacece of Madeira and
the Cape Verde Islands, plants that in the islands of the Pacific and
elsewhere raise much the same issues. This explanation seems very
probable as concerning Draccena draco, but it could not be applied
to the Hawaiian plant.

Let us look for a moment at the modes of dispersal possessed by
Dracsenas generally. Though in the cases of the Canarian and
Hawaiian species the seeds even after prolonged drying possess no
buoyancy, being in this respect doubtless typical of the genus,
the berries would readily attract birds. The seeds of Dracsenas
are indeed well fitted for withstanding a transport in a bird's stomach,
the small embryo being protected by a very tough albumen. But
whether they could be thus carried unharmed across the 3000 to
4000 miles of ocean that intervene between the eastern borders of Asia

APPENDIX

489

and the Hawaiian Islands is another matter. Yet in Hawaii, Draccena
aurea shares this difficulty with several other trees, such as Sider-
oxylan (Sapotacece) and Elceocarpus, that are known in other localities
to be locally dispersed by pigeons {Plant Dispersal^ pp. 372-4, 377).

One point that should be remembered in connection with the survival
of species of Draccena on islands is the tenacity of life displayed by
D. draco in the Canaries. That the tree would make a vigorous
effort to contest extinction is indicated not only by the manner of
its growth, but also by its capacity of vegetative reproduction.
Not only can it be raised from cuttings ; but it seems highly probable
that if the tree was greatly injured by the wind, so that it lay in
fragments on the ground, it would sometimes be able to reproduce
itself from the tops of the branches. An experiment by Mr. Bain
in this direction is recorded in the ninth edition of the Encyclopedia
Britannica (XII., 236). After the top of a Draccena draco, which
had been slowly separated from the stem, had been suspended some
months in a bushy covering, it protruded roots, and subsequently
established itself when lowered into the soil.

Note 32 (p. 265).
A comparison of the old and later charts of the Turks Islands,

Here are compared a French chart of 1753 and the British Admiralty
chart mainly based on the survey of 1830. The French chart, which
is in the British Museum library, describes itself as " from a survey
made in 1753 by the sloops L'Aigle and VEmeraude by order of the
French Governor of Hispaniola with improvements from observations
made in 1770 in the Sir Edward Hawke, King's Schooner." It was
published in 1794 by Laurie and Whittle, 53 Fleet Street, London ; and
is drawn on a scale of three inches to four miles. The Admiralty
chart (No. 1441) is based on Captain Owen's survey of 1830 with
additions to 1845 and large corrections in 1864-5 and 1898, the scale
being much the same as in the French chart.

The names of the larger islands in the French chart are those in
present use. Thus we have Grand Turk, Cotton Island, Salt Key,
and Sand Key ; but the last, which is now known by the inhabitants
as Greater Sand Key, is there stated to be " sometimes called Foul
Key or Seal Key." The names of the smaller islands are all different
from those in the Admiralty chart which are those now employed in
the group. Thus Long Key is there named PeUcan's Island, Pear
Key is Bird's Island, Eastern Key is Breeches Island, and Toney
Rock to the south of Eastern Key is called The Centry. Gibb Key
and Round Key are named The Twins. However, the small eastern
islands are only rudely indicated in the French chart, and Penniston
Key is omitted altogether — an evident error, since it could not be of
recent origin.

For nautical surveys in those times and in those seas, this early
French chart may be regarded as fairly complete. Three fixed posi-
tions were obtained by astronomical observation, the latitude and
longitude for the south-west corner of Grand Turk, and the latitude

490

APPENDIX

for the middle of Salt Cay and the middle of Greater Sand Cay.
The error in the longitude, as compared mth the Admiralty chart,
is about forty minutes on the minus side, and that of the latitude
ranges from almost nothing to two miles. Except in the case of
Grand Turk, the dimensions of the larger islands as given in both
charts do not differ greatly — the length of Grand Turk in the French
chart being three and three-quarter miles instead of nearly five and
a half miles as in the later chart. Unfortunately the period for the
valid comparison of the two charts is limited to only sixty years,
namely, between 1770 and 1830, since the additions are not dis-
criminated in either case.

The soundings in the French chart, though far fewer than in the
Admiralty chart, are fairly well distributed over the bank. The
comparison, as far as it goes, indicates that the maximum depths
over the bank were the same at the time of the French survey as
they were during the English survey. But the depths were more
uniform; and evidently the numerous shoals that now exist in
different localities between the islands, as between Grand Turk and
Cotton Cay, were not charted by the early surveyors. The limits of
the bank are imperfectly determined in the French chart ; but one
or two areas lend themselves for comparison. All the area of the
bank lying south and east of a line drawn from Greater Sand Cay
through Salt and Cotton Cays to Pear Cay, and thence north-east to
the edge of the bank, displays a uniform depth in the French chart
of nine or ten fathoms. This is in a general sense the depth-condition
exhibited in the Admiralty chart over the greater part of this area,
except amongst the cays between Salt Cay and Toney Ruck. Here
soundings of seven and eight fathoms prevail towards the edge of
the bank, and further in amongst the cays numerous shoal patches
covered by less than three fathoms of water exist, the prevailing
intervening depths being about five fathoms.

Considerable changes seem also to have occurred in the area
between Cotton Cay and Grand Turk. Here the sea is so beset with
shoals and reefs that, as I know from my own experience, navigation
at night is dangerous. In the French chart it is credited with a
uniform depth of three and four fathoms, three in the northern half
and four in the southern half of the area. In the Admiralty chart,
although maximum depths of three fathoms in the northern third
and of four and five fathoms in the southern two-thirds are indicated,
numerous shoals, often with rocks awash, are also marked. Reef-
growth has evidently been active in these waters since the time of
the French survey, and it is probable that Lesser Sand Cay, a con-
spicuous sandbank midway between Grand Turk and Cotton Cay,
on which vegetation at times gains a hold, did not then exist.

With reference to the changes in the islands indicated by a com-
parison of the two charts, the most noticeable one is the filling up
of a channel two feet deep, which in 1753-70 cut off the northern
third of Greater Sand Cay. In Captain Owen's chart the island
appears to consist of two parts connected by sandbanks that are
covered at high-water. But it may be that this was its condition
in 1898, when the last important additions were made. At the

APPENDIX

491

present time, as I was informed, the neck of sand south of Beacon
Hill is sometimes breached by the seas during stormy weather. In
1911 the islet off the north-east side was separated by a narrow,
shallow passage nearly exposed at low-water.

A puzzling feature in connection with Grand Turk is that the
North Creek is represented in the Admiralty chart as cut off from
the sea to the north by a tract of low land half a mile broad. This
seems inexplicable. The present condition is well brought out in a
map of the island made in 1902-4 by J. F. Osborn, Colonial Sur-
veyor, where it is shown that the North Creek approaches within
about 300 yards of the sea, with which it once communicated by a
broad passage, 200 yards across, that is now more or less silted up.

In connection with Greater Sand Cay there is a note in the old
French chart to the following effect : " Upon this Bluff (the southern
end of the island) the French, after the late Peace, erected a Sea
Mark, which they were soon after obliged to demolish." This may
perhaps explain a reference to this island in the West India Pilot,
Part III., p. 370, 1909, where it is stated that *'the remains of some
remarkably solid masonry on the cay are similar to those which may
be seen at Cape Isabella on Santo Domingo-Haiti."

Note 33 (p. 361).

Plants collected by George Forster in Fayal (Azores) in 1775.

(Commentationes Societatis Regies Scientiarum Gottingensis, Vol. IX.,
1787. The paper is entitled " Plantae Atlanticse ex insulis Madeirae,
St. Jacobi, Adscensionis, St. Helenae, et Fayal reportatse." The
species are stated to be all Linnean. A indicates that the species
has not since been recorded from Fayal but from other islands of the
group. F indicates that it has since been found by Watson, Brown,
and others on Fayal.)

F. Verbena officinalis.
F. Cyperus esculentus.

Cyperus compressus.
F. Milium lendigerum (= Gastridium lendigerum, B.).
F. Polycarpon tetraphyllum.
F. Schergerdia arvensis ( = Sherardia arvensis).

Borago officinalis.
F. Physalis peruviana.
F. Solanum pseudo-capsicum.

Nerium oleander.

Gentiana centaurium ( = Erythrsea ramosissima, Pers. I K).^
A. Erica scoparia.^
F. Reseda luteola.

^ It seems likely that Erythrcea centaurium, Pers., is here meant. It is now common
over the group, including Fayal, and was found by Hochstetter as far back as 1838.

* Trelease suggests that the true Erica scoparia, L., which was found on the island
off Villa Franca (San Miguel) by Hochstetter, was merely a form of Erica azorica,
the common Tree-Heath of the islands. This, however, appears unlikely, since
Hochstetter himself differentiated the Azorean species.

492

APPENDIX

F. Mentha rotundifolia.
F. Mentha pulegium.

Malva mauritiana ? ^
F. Spartium junceum.
F. Vicia sativa.
A. Ornithopus perpusillus.
F. Trifohum arvense.
F. Lotus angustissimus.
A. Hypericum perforatum.
F. Hypericum humifusum.
F. Crepis virens.

Hypocharis radiata ( = Hypochoeris radicata).^

Carthamus tinctorius (Safflower).
F. Gnaphahum luteo-album.
F. Pteris aquilina.
F. Asplenium marinum.

Lycopodium plumosum.

These plants were collected during a stay of four or five days in
July 1775, made by the Resolution under Captain Cook. Of the
thirty species above named, three-fourths are included in Watson's
catalogue. This proportion would be considerably increased if we
dealt with the species of Gentiana, Malva, and Hypochoeris, as indi-
cated in the footnotes, and considered that the Safflower and the
Oleander as cultivated plants would have been excluded by Watson
altogether.

W^ith the exception of the two ferns and the lycopod there is
hardly a plant in this list that could be regarded as having been
present in the Azores before the discovery of the group in the first
half of the fifteenth century. Of the flowering plants two-thirds
are weeds of cultivated and waste places, many of w^hich are known
to have been spread through man's agency over much of the world.
Others, such as the species of Physalis, Solanu7n, and Spartium, as
well as Cyperus esculentus, are stated by Watson and Trelease to
have been introduced, or are labelled as weeds without comment,
and most of them are well known to be plants, as in the first three
cases, that have often been introduced by man, either intentionally
or accidentally, in other parts of the world. The Safflower and the
Oleander, as above indicated, are not included by Watson and
Trelease in their lists of plants, either indigenous or introduced.
They may be observed in the small cottage gardens and ornamental
gardens of our own time.

The above list is useful as showing that many of the plants that
do not belong to the Azorean flora were introduced long ago. Most
of them, it is true, were observed by Hochstetter in 1838, but for
the plants it concerns this list carries us sixty-three years further
back. Within a year or two of each other, George Forster (1775) was

^ Malva nicceensis, All., collected by Watson and Godman only in Fayal, was in
the first place named by the former 31. rotundifolia.

* Possibly Hypochoeris glabra, L., which much resembles H. radicata, L. (B. and
H.), and has been since found on Fayal and other islands.

APPENDIX

493

collecting the weeds and Francis Masson (1777-8) was enriching the
gardens at Kew with the indigenous trees and shrubs of these islands
(Aiton's Hortus Kewensis, 1789). Yet if man's interest is more
attracted by the second, the history of our race is intimately bound
up with the first, and weeds offer from this standpoint almost virgin
ground for the investigator.

Note 34.

Observations on the medanos or moving sand-hills of the Ancon
coast region in Peru. (General remarks on this subject will be
found on p. 271).

The following observations were made in February 1894 in the
Ancon district north of Callao. Broad, sandy, and almost barren
plains extend inland from the shores of Ancon Bay for about three
miles to the foot of the mountains, rising in that distance 200 to 300
feet, the sand on the plains being only a foot or two in depth. A
sand-covered spur of the mountains descends to the coast on the
south side of the Ancon plains, having an elevation opposite the
town of 400 feet. Immediately south of the spur is a large sandy
beach, the Playa Mayor, more than a mile in length, which was the
starting-place of a line of medanos that at the time of my visit took
an oblique north-easterly course before the prevailing south-west
winds of four and a half to five miles to the base of the inland range
of mountains. The whole of the region here concerned up to an
elevation of 500 feet was only a sandy waste, where a tumble-weed
of the genus Tillandsia alone found a home.

As tj^pically displayed, these sand-hills are crescentic in form,
twenty-five to thirty feet across, and six to ten feet high, the con-
cavity being in front. That they are ever advancing was indicated
by the way in which they lay astride the beaten tracks. I observed
these medanos after they had reached in irregular order the top of
the spur overlooking the Ancon plains. One was perched on the
crest at an elevation of 200 feet above the beach, another on the
crest at 300 feet, and a third at 360 feet. Before a light wind with
a force of about three the sand was steadily moving across the crest,
the heavier particles along the surface and the lighter blown through
the air. In ten minutes, sand of the weight of 108 grains was blown
into the mouth of a round tube, an inch in diameter, that had been
placed on the surface. I felt a light rain of sand on my face as I
sat watching, and when the wind freshened for a few moments my
face was " peppered " with sand. All the sand of the surface was
in motion on the crest, both on the medanos and in the spaces
between them. I noticed that after the medanos had crossed the
ridge they re-formed in an irregular fashion on the descending
slopes, unless the descent was steep, when the sand formed a con-
tinuous slide. On reaching the plains, 200 to 350 feet below, the
medanos resumed their typical shape and gathered into line, or
rather into column, for the traverse of the plains. Arranged two
or three irregularly abreast in a column about 100 paces in width.

494

APPENDIX

the medanos crossed the plains obhquely in the same north-easterly
direction for about three miles to the foot of the mountains, ascend-
ing the lower slopes about 500 feet, and here the sandy area termi-
nated. In their traverse of the plains this column of medanos
crossed two hill ranges that rose 100 and 150 feet above the plains.

By careful measurements on three medanos I ascertained that in
five days they had advanced about a foot, the prevailing winds
being light and from the south-west. From time to time slides take
place down the steep face of the concavity, the sand caking a little
on the surface and forming layers, a half to an inch thick, that
slide to the bottom. Impelled by fresh winds, the medanos may
move yards daily, and when driven by violent winds, as we learn
from Dr. von Tschudi, the medanos pass rapidly over the plains.
Strewn over the ground all over the medano region is a much coarser
sand that could be moved only by strong winds. It is arranged in
wavelets about two feet apart and one to three inches high, and
remains at rest when the lighter medano sand is moving briskly
along.

Mbastjrements of the Sand -grains in the Region of Medanos (moving
Sand-dunes) in the Ancon Coast-district op Peru.

Finest
Material aver-
aging 2 mm.

in size

Medium
Material aver-
aging "3 ram.

Coarse
Material aver-
aging "5 mm.

Extra-coarse
Material aver-
aging 1-2 mm.

Sand blown through the
air a foot above the ground.

95%

5%

Sand blown along the
sarface of the ground.

80%

20%

Sand of a typical meda-
no four miles from the
starting-place above the
beach.

56%

44-5%

0-5%

Sand of a typical meda-
no one mile from the
starting-place above the
beach.

41%

58%

1-0%

Drift sand blown up the
hill-slopes 30 feet above
the beach just mentioned.

11%

69%

20%

Sand from the wavelets
spread over the medano
plains.

100 %

Note. — The prevailing winds were light with an average force of three.

The sand is derived from the disintegration of andesitic rocks. It
is composed in their order of frequency of grains of felspar, magnetite,
semi-vitreous volcanic rocks, pyroxene, quartz, brown mica, horn-

APPENDIX

495

blende, etc., calcareous particles being either absent or very scanty.
The magnetite mostly gathers among the finest materials, being
there especially frequent in the sand blown along the ground and in
the medanos that have travelled four miles from their starting-place,
the proportion making up 25 or 30 per cent, of the total. It is also
well represented amongst the finest materials of the sand blown
through the air. The grains of magnetite are always smaller than
those of the felspar. Thus in the case of the sand blown through
the air the magnetite grains average 0'12 mm. in size and the felspar
grains as much as 0*23 mm. The beach sand from between the tide-
marks has the same composition as the sand of the medanos and of
the plains.

It is interesting to notice how the fine materials are appropriated
by the medano as it proceeds inland from the coast. In the beach
sand blown up the hill-slopes, but below the place where the first
medano shapes itself, there is only 11 per cent, of fine materials.
When the medanos have travelled a mile inland the proportion is
about 40 per cent., and when they have extended four miles from
the starting-place it is 55 per cent. Except when composed of
softer calcareous materials, as in the case of the aeolian deposits of
the Bahamas, " the ordinary drifted sands of seaside dunes show
little rounding " (see Grenville Cole's Practical Geology, 1898, p. 189).
This is especially true of the dunes or medanos of the Ancon district.
The sand-grains of the medanos four miles from the beach were
most affected by attrition; but even they could only be described
as sub-rounded. The sand-grains of the medanos a mile from the
starting-place and the sand blown through the air were still less
rounded, and could be only termed sub-angular. The extra-coarse
sand of the wavelets or ripplets spread over the surface of the medano
plains, however, displayed the effects of attrition in a marked degree,
the angles of the grains being well rounded.

Note 35 (pp. 55, 484).

Bottle-drift in high latitudes of the North Atlantic.

The tracks are given in the American charts for several bottles
thrown into the sea between Newfoundland and Greenland which
were cast up on the coasts of Ireland, Scotland, and Norway, reach-
ing even to the North Cape, the velocity of the swiftest being eight
to nine miles a day. One, however, dropped over about 100 miles
south-east of Cape Race, was recovered on the south coast of Iceland
sixty-seven days afterwards, the distance of 1950 miles having been
accomplished at a minimum daily rate of twenty-nine miles (see
No. 95 in the U.S. Pilot Chart of the North Atlantic for November
1908). The most northerly traverse of the North Atlantic that is
illustrated in the American bottle-drift charts is one marked 109 in
the U.S. chart just named. Here a bottle drifted from a position
about 300 miles south-east of Cape Farewell to the North Cape of
Norway. However, through a printer's error, the daily rate is given
as 34-6 miles instead of 3*46 miles. But bottle-drift from off the

496

APPENDIX

southern end of Greenland is just as likely to be carried south in its
traverse of the Atlantic. Rennell mentions a bottle that was re-
covered on Teneriffe rather over two years after it had been cast
over from H.M.S. Hekla (Captain Parry) on June 16, 1819, in a
position about 140 miles south-west of Cape Farewell. This is
evidently the " highly remarkable and even enigmatical drift " to
which Dr. Schott refers on the first page of his memoir, though he
here quotes from the Physical Atlas of Berghaus. However, in the
light of facts to be now given the track of this bottle loses a little of
its remarkable character.

Rennell gives the records of four bottles thrown over in Davis
Strait in 1818 and 1821 by Captains Parry and Ross, the northern-
most in lat. 65° 40'. After periods of from eight to fourteen months
they were recovered on the coast of Donegal (two cases), the west
coast of Scotland, and the Hebrides. Two of them dropped over
within two days of each other and about three degrees of latitude
apart (62° 5' and 59° 8') were found afloat within a fortnight of each
other, thirteen and a half and fourteen months afterwards, off the
Donegal coast and off the Isle of Staffa (W. Scotland).

Note 36 (p. 388).

The wells of Pico in the Azores.

Just as on San Miguel and other large islands of the group, there
are no permanent rivers and but few surface streams on Pico ; but as
the frequent occurrence of the local name of "Ribiera" indicates,
there are numbers of torrent-beds and watercourses, which, although
they carry off the water after heavy rains, are dry during most of
the year. One of the sights of the great cone of Pico is the deep
gorge of the Ribiera Grande, which has been scooped out of the
precipitous mountain-side to the east of San Mattheus, the slopes
rising up from the coast to a height of 3000 feet within half a mile.
It is probable that at the time of their discovery, when the islands
of the Azores were densely wooded, the streams were more permanent
in their character. Generally speaking, on the island of Pico at the
present day the only surface water is the standing water of the
upland swamps and of the mountain lakes and ponds. I did not
come upon any thermal springs on this island, nor does there appear
to be any stream of a permanent character partially fed by hot
springs, such as we find in the case of a stream draining the Furnas
Valley in San Miguel, which empties into the sea at the village of
Ribiera Quente.

The condition of things on the island of Pico is probably to some
degree typical of the other large islands of the group, excepting
perhaps San Jorge. There are no springs on the great mountain,
and apparently but few in the eastern part of the island. Yet fresh
water oozes into the sea all around the coasts. Those of the peasants
of the coast villages, who are too poor to build a covered rain-tank
of masonry, obtain their water supply from wells sunk in the rubble
of large and small blocks of lava immediately behind the beach.

APPENDIX

497

Probably most of the water issues at the coast between the tide-
marks, and it is here that women hving far from a well often wash
their linen.

The seaward soakage of the underground waters is a frequent
phenomenon around the shores of lofty volcanic islands, or of high
volcanoes rising like that of Etna near the sea. Often the water
gathers in subterranean streams which emerge at the coast and in
the depths beyond, as I have described in the case of Hawaii and
Etna in the first volume of my Observations of a Naturalist in the
Pacific (p. 38). In Pico, as above observed, it displays itself chiefly
in the oozing of fresh- water between the tide-levels on the beaches.

At times the seaward soakage of underground waters gives rise to
a number of subterranean streams of fresh-water that well up in the
sea off the coasts of large islands. Mr. Samler Brown in his Guide
to Madeira and the Canary Islands (1905, e, 22; i, 2) refers to the
streams of fresh- water that rise up in the sea near the coasts of those
islands. In La Palma, for instance, much of the rainfall on the
wooded slopes of the mountains " filters through into the sea at
short distances from the coast-line." My readers will recall Hum-
boldt's reference to the occurrence, a few miles off the Gulf of Xagua
on the south coast of Cuba, of very extensive fresh-water springs,
from which ships can water (Lady Sabine's translation of Ansichten
der Natur, I., 161). But submarine springs may exist along con-
tinental coasts, even where there is no great elevation. Thus Dr.
Scharff in his book on The Origin of Life in America (1911, p. 169)
quotes Prof. Shaler to the effect that along the coasts of Florida
there arise from beneath the sea a number of submarine springs.

But to return to the subject of the coast wells of Pico, it may be
observed that the water is always a little brackish. As with those
of San Mattheus, Magdalena, Caes-o-Pico, Praynha do Norte, and other
places at the sea-border, the wells have sometimes to be sunk to a
depth of fifteen to twenty feet, the level of the water being that of
the sea. But their water is in summer much cooler than that of the
sea. At 5 p.m. on July 28, when the temperature of the well-water
at Praynha do Norte was 60° Fahr., that of the sea was 72*5°. Per-
manent springs, as I have said, are only to be found off the great
mountain, and they are few in number. However, the coast village
of Santo Amaro is supplied with water by a spring which issues on
the mountain slopes about 2000 feet above the sea, its temperature
at 3 p.m. on August 3 being 54° Fahr., or about ten degrees cooler
than the mean temperature of the air in the shade at that altitude.

A similar spring is said to exist far up the mountain-side behind
Caes-o-Pico ; but it is not utiHsed by the villagers. At the head of
a gully, some 500 or 600 feet above this place, there is a water-
source which has been protected by masonry; but it seems to be
only used for washing clothes. Here the water is derived from the
drippings of cliff-faces on either side, the line of underground soakage
being cut across by the gully, a circumstance which shows that in
this eastern part of the island there is a large amount of fresh-water
available. But lack of funds is the great obstacle, though a little
enterprise, like that displayed by the inhabitants of Santo Amaro,

K K

498

APPENDIX

might provide several other of the coast villages with good water
from the mountains. Dripping-cliffs, in particular, ought to be
fairly common; and, since they afford a substitute for permanent
springs, they might readily be utilised for this purpose.

Note 37 (p. 358).
Uncinia.

It has been shown in Chapter XVI. that a few species of Car ex
have probably crossed the Southern Ocean between the southern
portion of South America and the Australian and New Zealand
region. Considerable light is thrown on the possibility of this
oceanic traverse by the distribution in high southern latitudes of
another genus of the Caricoidece, namely, Uncinia, which is essentially
a genus of these latitudes, since four-fifths of its species are there
confined.

The twenty-four species recognised in Kiikenthal's monograph on
the Caricoidece {Pflanzenreich, 1909) are chiefly divided between the
two widely sundered regions centering in the southern extreme of
South America and in New Zealand. The two regions, however, are
connected by a single species {U. macrolepis) found both in the
southern island of New Zealand and in Fuegia; and they are in-
directly linked together by the association in the intervening islands
of Amsterdam and St. Paul of a New Zealand species, U. compacta,
and a Fuegian species, U. brevicaulis (see Hemsley's Chall. Bot., III.,
159, 267).

The species are about equally divided between the two regions.
South America holding twelve and New Zealand thirteen species.
Of the South American species six are confined to the southern
portion extending from South Chile to Fuegia; two are spread over
much of the continent and reach in one case Central America; one
{U. jamaicensis) is confined to the tropical and subtropical portions
of South America and to Central America and the West Indies,
occurring often at high altitudes ; one is peculiar to Juan Fernandez ;
and the last two are Antarctic species, extending in one case to the
islands of Tristan da Cunha, St. Paul, and Amsterdam, and in the
other to the South Island of New Zealand. Of the New Zealand
species seven are restricted to that region and to the neighbouring
small islands (Stewart, Antipodes, Chatham, etc.); and six extend
to regions outside, namely, four to Australia and Tasmania, one to
Hawaii, and one to Antarctic South America. This does not exhaust
the limits of dispersal from the New Zealand centre, since among the
species it has lent to Australia one has reached New Guinea and
another Amsterdam and Kerguelen Islands.

Two significant facts of distribution are here disclosed. In the
first place, as regards the New Zealand group of plants Australia has
no species of its own, every species occurring outside New Zealand
and the small islands near being a New Zealand species, even in such
distant localities as New Guinea and Hawaii. In the same way the
southern part of South America is still the abode of ten out of the

APPENDIX

499

twelve species found in that continent. The other fact is the absence
of Uncinia from South Africa and from the African continent gener-
ally. One might have looked for a representative on Table Mountain
of a genus that has found a home on the isolated oceanic islands of
Tristan da Cunha and St. Paul, etc., on either side of the continent.

Yet the absence of Uncinia from South Africa is quite consistent
with the usual behaviour of plants common to the southern part of
South America and the Australian and New Zealand region. Hemsley
gives a long list of plants (Chall. Bot.y I., 52) illustrating the relation-
ship of these two regions. A large number of flowering plants
belonging to about ninety-three genera are included, the grasses
being excluded. The mode of presentation does not admit of one's
giving a precise numerical value to the results ; but it would appear
that not over one-tenth of the species common to the South American
and to the Australian and New Zealand regions occur in Africa. The
indications of the cyperaceous species in this list alone are very
suggestive. Out of a dozen species, belonging to six genera, all
either occur both in South America (mainly in the south) and in the
Australian and New Zealand region, or they are represented there
by closely related forms; but only two of them are also found in
South Africa. When dealing with Carex in Chapter XVI., it was
pointed out that of twenty-one Australasian species found outside
that region six occur in South America and only one in South Africa.

It has already been remarked that the South American and New
Zealand centres of Uncinia are still in touch with each other, since
they hold a species in common and since species from the two centres
meet in the intervening islands. The point we are now concerned
with is the direction in which the inter-communication takes place;
in other words, the direction in which species of Uncinia would be
likely to travel around high southern latitudes. The latitudes in-
volved correspond approximately with the zone of the Westerly
Winds, the belt of the Roaring Forties. Those who, like the writer,
have performed the voyage before the strong Westerlies from the
Cape to Australia in a sailing vessel and have watched the sea-birds
following in the ship's wake for weeks together will be in a position
to appreciate the influences at present determining the part taken
by the bird in distributing seeds in these latitudes. These sea-birds
travel around the globe in the belt of the Westerlies, and a case has
been recorded where a Cape Pigeon {Daption capensis), marked by a
ribbon around its neck, followed a ship for 5000 miles on its way
home from Australia by Cape Horn (Coppinger's Cruise of the Alert,
p. 18). Ever since 1888, when a letter of mine appeared in Nature
(May 10) concerning this matter, I have held the view that South
America has been a funnel from the Fuegian tip of which plants
have through the ages been detached and carried ever eastward
through the agencies of the westerly winds, the west-wind drift-
current, and sea-birds. The efficacy of the sea-bird in these lati-
tudes was brought home to me a few years before that date, when in
1881 I found a seed, apparently sound, in the stomach of a Cape
Pigeon caught by one of my mess-mates 550 miles east of Tristan da
Cunha (Nature, XXVI., 12; ChalL Bot., I., 45; IV., 313).

500

APPENDIX

It is to the sea-bird that we are obhged to appeal in the case of
Uncinia, the hooked fruits of which, as is observed below, are well
fitted for attachment to a bird's plumage. Yet Sir Joseph Hooker
in the case of the flora of Kerguelen, whilst admitting that the winds
which blow, as he remarks, from Fuegia to Kerguelen almost through-
out the year, are the most powerful natural agents for distributing
cryptogamic spores, rejects the agency of the bird. He finds it
difficult to imagine how seeds could adhere to birds in their flight of
4000 miles across a rough ocean, which is the traverse here implied
(Phil. Trans. Roy. Soc, Vol. 168, 1879; see also Hemsley in
Chall. Bot., I., 51). Yet the later observations of Moseley, Kidder,
and others well illustrate how from their nesting habits in the islands
of the Southern Ocean, such as Kerguelen, Tristan da Cunha, etc.,
albatrosses, petrels, and other sea-birds would be very likely to
transport seeds in their plumage, a subject discussed in my work on
Plant Dispersal (p. 276, etc.). This would certainly apply to the
case of Accena^ one of the most typical genera of these regions,
the fruits of which, as Moseley observes, stick like burrs to
feathers.

Observation has shown that the hooked fruits of Uncinia may be
as firmly entangled in a bird's plumage as those of Accena. Morris, in
a paper in Nature (Dec. 16, 1886) on the dispersal of plants by
birds, takes the fruits of Uncinia jamaicensis to illustrate dispersal
in a bird's feathers. This species, which has a wide distribution in
Central America and in tropical and subtropical South America,
grows on the highlands of Jamaica at altitudes of 5000 to 6000 feet.
Migratory birds, as he states, on their way north and south between
North and South America rest on these Jamaican uplands, and so
exhausted are they that they have been easily caught with the
hands. In two cases he found small migratory birds on these moun-
tains, which were so completely entangled in the hooks of Uncinias
that they were unable to escape. Large birds, he says, would break
away ; but not without carrying off in their plumage a number of
the fruits. The exserted hooked " rachilla " of the fruit is, he says,
excellently adapted for catching firmly in plumage.

Assuming that birds have thus distributed Uncinias over the
Southern Ocean, there can be no hesitation in considering that their
flight must nearly always have been east before the westerly winds.
Under these circumstances one could scarcely look for any very
definite arrangement of these and other plants concerned, since
Fuegia would be ever supplying them to New Zealand and the
intervening islands, and New Zealand would be ever returning them
to Fuegia. Yet such an arrangement can be to a small extent
detected. Hemsley, though he does not accept the implication,
writes that " numerically there is a preponderance of Fuegian forms
represented in Kerguelen and the other islands under consideration
(Marion, Crozets, Heard), as opposed to what may be termed New
Zealand forms " (Chall. Bot., III., 253). The endemic species of these
islands, he adds, " exhibit, perhaps, a closer affinity with Fuegian
than with New Zealand species." Yet, notwithstanding, he con-
siders that " with all the facts before us there does not seem to be a

APPENDIX

501

special affinity between the floras of Kerguelen, etc., and Fuegia, as
distinguished from the flora of the zone generally."

Perhaps fresh light may be cast on this matter if we regard the
story of the differentiation of the genus within itself as indicated in
Kiikenthal's pages. Of the two subgenera recognised by Clarke and
himself, Pseudo-Carex and Eu-Uncinia, the first holds only a single
species, Uncinia kingii, which is confined to Fuegia and from its near
approach to Carex supplies a connecting link between the two genera
(Kiikenthal, pp. 25, 66, 109; Hemsley, Chall. Bot., I., 31). Carex
microglochin, which belongs according to Kiikenthal (pp. 11, 26) to
Primocarex, the oldest of the four subgenera of Carex, is the species
to which it is most closely related. It is an arctic-alpine plant of
Eurasia and North America, and is associated with Uncinia kingii in
Fuegia. The second subgenus, Eu-Uncinia, holds the other twenty-
three species. It was subdivided by Clarke, and his opinion is adopted
by Kukenthal, into two sections, Platyandrce and Stenandrce, the
distribution of which offers the critical point in this discussion.
The first holds six species, all of which are South American, one of
them reaching the islands of Tristan da Cunha, Amsterdam, and
St. Paul. The second section, Stenandrce, holds seventeen species,
or about three-fourths of the species of the genus. Four of them
are exclusively South American (South Chile and Fuegia). One
(U. macrolepis) is common to Fuegia and the South Island of New
Zealand. The rest belong to the New Zealand centre, seven being
endemic, the others spreading to Tasmania, Australia, Amsterdam,
and Kerguelen, and even to New Guinea and Hawaii.

The situation thus revealed is this. Although the species of the
genus are about equally shared between the two centres. South
America and New Zealand, South America holds both subgenera and
both the sections of the subgenus, Eu-Uncinia. On the other hand,
the New Zealand centre holds only one subgenus and only one of its
two sections, namely, Stenandra: ; but it claims the majority of its
species. The upshot of the discussion is that whilst South America
was the original differentiating ground of the genus, New Zealand
has been the principal centre of " formative power " in later times,
the single section, which the last-named region holds, being the
most vigorous and productive of the Uncinias. Some of the general
arguments that would assign to Eu-Carex, the subgenus comprising
two-thirds of the known species of Carex (793 in all), the last place in
the development-scale of the genus (see Kukenthal, pp. 11, 25, 26),
could be applied to the section Stenandrce in the case of Uncinia,
both of them holding the bulk of the species and displaying in their
development of new forms as well as in their great range the highest
degree of virility.

Note 38 (p. 450).

The fruiting behaviour of Atriplex portulacoides, L., at Salcombe,

South Devon.

This plant came under my notice only in one locality in the Sal-
combe district, namely, on the shore of Blanksmill Creek, where it

502

APPENDIX

formed in 1906 a single patch a few feet across. The following notes
were made on it in that year.

Jan. 17, in full leaf ; some stems bearing immature fruits. June 30,
beginning to flower. Aug, 31, flowering copiously, also in early fruit.
Oct. 5, foliage still abundant; in seed; but the nuts are soft and
whitish and the albumen is creamy and not set, whilst the fully
formed dark-green embryo seems almost escaping through the
delicate membranous fruit-covering. Nov. 9, abundant healthy
green foliage and abundant green fruit; the fruit still soft, but the
green embryo has grown at the expense of the creamy albumen,
though still within the fruit-coverings.

Evidently the plant this year has been on the eve of vivipary.
The albumen never hardened and there was no rest period. Since
the plant appears to be most at home in the warmer climes of the
Mediterranean, it would almost seem that in the northern part of
its range it may endeavour to counteract the effects of colder climatic
conditions by dispensing with the rest period of the seed. From this
point of view the vivipary of the mangroves in the tropics might be
regarded as due to their endeavour to accommodate themselves to
climatic conditions cooler than those that once prevailed in those
regions.

Note 39 (Chapter XI).
On recent obseitations in the Western Bahamas by Dr. Vaughan.

The writer is deeply indebted to Dr. Vaughan of the U.S. Geo-
logical Survey for his great courtesy in sending him some of his
papers on the Bahamas and in replying to his numerous queries
on the subject ; but unfortunately his letter came too late to enable
its contents to be utilised in Chapter XI, which is concerned with
the geology of the Turks Islands. The remarks below refer to
points raised in that chapter under the pages indicated.

The oolitic character of the grains of the ceolian formation or cal-
careous sandstone of the Bahamas (p. 260). — In the first place,
it should be noted that L. Agassiz, in his paper on the Salt Key
Bank, long since remarked the occurrence of oolitic grains in the
fine sand of the bank, which is covered b}- four or five fathoms of
water. Dr. Vaughan has watched the gro^^iih of oolitic grains in
the shoal-water muds of the Bahamian seas, muds that " only
need induration to become oolitic limestones." The precipitation
of the carbonate of lime is attributed to denitrifying bacteria, which,
as sho^vn by Drew and Kellerman, exist in enormous quantities in
the surface ooze of the Florida and Bahamian shoals. These oolitic
grains ultimately form the beaches and the dunes and the more or
less compacted aeolian rock.

Comparison of the ceolian formation of the Bahamas and the
Bermudas (p. 273). — According to Dr. Vaughan, although both
are calcareous, the mechanical conditions of the Bemiudian and
Bahamian formations are very different. Whilst in the first case
the deposits are composed of broken-up shells, tests of foraminifera,
and occasional coral fragments, in the second case through chemical

APPENDIX

503

precipitation in sea- water these materials have formed " nuclei '*
for the development of oolitic grains.

The foundations of the ceolian rock or wind-blown oolite of the
Bahamas (p. 262). — In reply to a question put by the writer, Dr.
Vaughan states that in the western islands the wind-blown oolite
rests on a foundation of marine oolite, and that in no instance did
he find " really coral reef rock interbedded with the oolitic rocks."
He adds that " after the (submarine) formation of the oolite, prob-
ably during a period of uplift, considerable quantities of material
were blown up by the wind and formed the dunes." These wind-
blown materials gave rise to the more or less compacted seolian
rocks ; and it would seem to the present writer that a critical point
of first importance would lie in the determination by borings and
other methods of the relation of the level of the base of the wind-
blown rock with reference to that of the sea. According to his
view the junction of the wind-blown with the marine oolite would
be found at or about the present sea-level; but if, as held by A.
Agassiz, there has been a subsidence of 300 feet since the formation
of the islands, it would be found far below that level.

The non-existence in South Florida of the calcareous ceolian oolite
of the Bahamas (p. 273). — It is a very significant fact that, as
Dr. Vaughan has informed the writer, this formation does not exist
in South Florida. Yet the islands of the neighbouring Bahamas
from end to end of the great archipelago are composed of this forma-
tion. There are extensive areas underlain by the marine oolite in
South Florida, but no wind-blown oolite is known. The sands
strewn over the interior of the peninsula, as well as those of the coast
dunes, are mainly siliceous.

The ocean-holes of the Bahama Banks (p. 258). — ^Dr. Vaughan
tells me that A. Agassiz was undoubtedly correct in his inference
of a considerable subsidence, which was based on the occurrence
of these holes in the banks. With much diffidence I would suggest
that their preservation during the ages that have since elapsed
presents a difficulty, since it is not easy to perceive why they were
not obliterated during the great destruction of the land-surface
that, according to Agassiz, accompanied the submergence and by
the accumulation of debris and the growth of marine organisms in
later times. These ocean-holes are described as representing blow-
holes, sinks, caverns, canons, etc., in the original land-surface.
Some of the smaller holes may have vertical sides with a sheer drop
of ten fathoms and more, and one might imagine that the same
submarine influences that produced them are still preserving their
patency.

A suggestion of the present writer for the comparison of the behaviour
of sand-dunes of different mineral composition. — It may be that
we cannot strictly compare the movement of sand in dunes formed
of calcareous oolitic grains with that of sand in dunes derived from
the disintegration of volcanic rocks, such as has been described in
Note 34 of this Appendix on the moving sand-hills of the Ancon
plains of Peru. A comparison of the two kinds of moving sand-
hills on the lines adopted in that note may be suggested. In the

504

APPENDIX

case of calcareous sand-dunes formed of oolitic grains, as in the
Bahamas, we might obtain some interesting results, and it may be
that under present conditions the behaviour of the calcareous sand-
hills of the Bahamas would be very different from that of the medanos
or moving sand-hills formed of volcanic rocks in Peru. In the
case of the Bahama deposits we ought to know in what way the
oolitic grains of the seolian rock differ as regards form and external
markings from those of the beach sand and from those of the mud
on the submerged banks. The effects of attrition ought to be very
pronounced in the case of the grains of the wind-blown rock. Much
depends on the answer to the query whether such effects of attrition
display themselves ; and in this and in other connections concerned
with these aeolian rocks of the Bahamas we must be prepared for
surprises.

(In addition to the papers of Dr. Vaughan, named at the end of
Chapter XI, may be mentioned a very interesting note comparing
the formation of the Floridian and Bahamian oolites in the Journal
of the Washington Academy of Sciences, May 19, 1913. The origin
of these oolites is also discussed in papers of more recent date on
the Floridian Plateau and on shoal-water samples from Murray
Island (Australia), the Bahamas, and Florida, in publications 133
and 213 of the Carnegie Institution of Washington, as well as in a
paper on the geology of the Bahamas and Southern Florida in the
Yearbook of the same institution for 1914.)

GENERAL INDEX

NoTi. — Several subjects are worked up in this index, which, on account of the
plan of the book, could not be treated connectedly in the text ; for example, the
sources of bottle-drift thrown upon the Irish coast and on the Carribean shores
of Central America.

Except where several references of importance are given, the figures in larger
type indicate the pages where the subject is treated at length, or where the most
important points are discussed.

Acacia, 167, 168, 171; A. acuifera, 287;

A. farnesiana, 166, 287
Aoaena, 294, 500
Acer, 326

Acrocomia, 3, 4, 11, 86, 91, 160
Acrostichum squamosum, 370, 375, 380,
425

Adder-stones, name of stranded West

Indian seeds, 21, 23
Adenocarpus viscosus, 408
iEohan rocks, in the Turks Islands and

Bahamas generally, 254-276, 452, 502-

504

Africa ; Carex and Sphagnum floras, 332-
358, 341-347, 356; current-connec-
tions, 294-312, 300-305, 311, 475-
477, 478 ; Uncinia, 499

West ; comparison of littoral flora

with that of the West Indies, 83-95,
141, 194, 207; bottle-drift, 49-53, 59,
67-71, 76-81, 475-477. See Sierra
Leone.

East ; bottle-drift, 50, 300-305

North ; bottle-drift on coast of

Morocco, 51, 52, 53

South ; bottle-drift, 63, 77

Agassiz, A. ; on the formation of the

Bahamas, 254-261, 269, 274-276, 503;

on the early maps of the group, 264,

276

L. ; on the Salt Key Bank, 261, 274,

276, 502
Agrostis castellana, 370, 372, 386
Agua do Pao, a mountain in San Miguel,

Azores, 438
Alton, 361, 493

Alacran Shoals, plants, 187, 188, 201, 231,
240, 250

Albatross ; in seed-distribution, 500
Alcyonarian sea-shrubs, in the Scilly
Islands and Norway, 21

605

Alder, name of Conocarpus erectus in the

West Indies, 201
Aleurites moluccana, 160
Algaroba, 102

Algarve (Portugal), introduction of

Myrica faya, 434
Allen, E. J., Physahse on EngUsh beaches,

29

J. A., on distribution, 325

Alligators, 102, 105, 107, 175; drifted to

the Turks Islands, 487. See Crocodiles.
"Alma Cummings " (derelict), its track,

69, 72, 472
Alnus maritimum (Conocarpus erectus),

201

Alternanthera, 85
AmarantacesB, 85

Amazon; seed-drift, 7, 8, 13, 19, 39, 74,
75, 81, 128, 129, 142 ; bottle-drift from
off the estuary, 62, 67, 70, 71, 74, 75, 80,
444, 445 ; plants chiefly of the estuary,
7, 128, 131, 133, 135, 141, 160, 212

Ambrosia crithmifoHa (A. hispida), 87,
172, 279-283, 288, 291, 451, 452

America, Central; recipient of seed-drift
by the North and Main Equatorial cur-
rents, 8, 72, 73 ; seed-drift on opposite
coasts, 17, 19; bottle-drift from off the
shores of Europe, 48, 53, 57 ; from the
vicinity of the Canary and Cape Verde
Islands, 57, 58; from between St.
Paul's Rocks and the coast of Brazil,
50, 61 ; from off the Amazon estuary,
75; from between Hispaniola and the
Turks Islands, 466; dereUct from off
Cape Hatteras, 50, 472

North ; bottle-drift to Europe, 52-

55, 66, 68; Carex and Sphagnum
floras, 332-358

South; current-connections, 294-

312, 297, 299, 310; Carex and Sphag-

506

GENERAL INDEX

num floras, 332-358, 335-341, 356;

Uncinia, 498-501
American genera in Macaronesia, 408,

410, 412, 413, 416
Amsterdam Island; Sphagnum and

Uncinia, 344, 346, 498. 501
Amulets, West Indian drift-seeds as, 22,

24

Anacardium occidentale (Cashew-nut),

28, 36, 173
Anagallis filiformis, 480, 481
tenella, 371, 377. 379-381, 387.

402, 417, 419, 425, 479
Anchovy Pear. See Grias cauliflora.
Ancon (Peru). See Medanos.
Andira inermis (Anseleen-tree), 4, 11, 16,

86, 88, 91, 92, 957 150
Andrews, E. C, on the Australian flora,

171, 317-319, 322, 330
Andropogon glomeratus, 451, 453
Angeleen-tree* See Andira inermis.
Annual Register, 277, 487
Anona, 174^181; A. cherimolia, 177; A.

glabra, 181; A. klainii, 181; A. muri-

cata (Sour Sop), 177, 181 ; A. palustris,

4, 5, 18, 86, 90, 174-181, 194; A.

reticulata (Custard Apple), 177; A.

senesalensis, 181 ; A. squamosa (Sweet

Sop)T 177

Antarctica, as a centre of dispersion, 309.
328, 330

Antarctic latitudes (Southern Ocean);

seed-distribution bv sea-birds, 294.

498-501 ; Carex and Sphagnum, 337-

340, 348, 349; Uncinia, 498-501;

bottle-drift, wreckasre. and currents,

295, 296, 299, 300, 306, 310
Antidote Vine. See FeviUea cordifoUa.
Antillean Stream, 10. 14, 19, 58, 62, 73,

79, 463-469, 471, 481
Antilles, Greater; bottle-drift, 56, 57, 61,

72, 73, 442-445
Lesser; bottle-drift. 57, 58, 60,

61, 62, 69. 71-75. 442-445
Antipodes Island, 348, 498
Antoine, 431

Aquatic plants ; in Jamaica. 16, 104-107 ;

in Azores, 371, 378-382, 387, 403, 405,

407, 417, 420, 439
Arabis albida, 411

Arachis hvpogaea; in European beach

drift, 28^, 29
Araucaria, 294, 328
Arbutus, 408
Arcangeli, 405, 426, 437
Arceuthobium oxrcedri, 360, 370, 375,

379, 386, 401, '426; distribution of

genus, 426
Arctic latitudes, bottle-drift, 484, 495
Arenaria serpyllifolia, 411
Argemone mexicana, 290
Argythamnia argentea, 287
Aridity and cold currents, 271, 272, 275

Armeria ; maderensis, 411 ; maritima, 187

Aroids ; cUmbing, 16 ; arborescent, 455

Arundo saccharoides, 105, 106

Ascension Island ; bottle-drift and posi-
tion as regards currents, 60, 67, 70, 76,
81, 443, 460, 474, 475, 482, 483 ; flora,
459, 460

Asplenium marinum, 492

Astrocarvum, 6, 12-14. 25-27, 37, 38,
86, 9i: 181

Atlantic, currents and bottle-drift, 46-82,
475-^77; drift-rates, 65-71; general
results, 71

Xorth; currents and bottle-drift,

46-59; circulatory movements, 51,
54, 55, 71, 72, 80, 471; bottle-drift in
high latitudes, 484, 495; general
results, 71. ^€6 Gulf Stream, North
Equatorial, Guinea, and Counter
Equatorial Currents.

South; current -system. 59, 60, 62;

bottle-drifts, 59-64,' 67, 69, 70, 71;
current -connect ions with Indian and
Pacific Oceans, 63. See Main Equa-
torial, Brazilian, Guinea, and Counter
Equatorial Currents and Amazon
bottle-drift.

Atlas, Great ; plants in the Azores, 405,
408

Atriplex portulacoides, 448-450, 501

Australia : current -connections and bottle-
drift, 49, 60, 63, 140, 294-312, 297,
309, 310; diferentiation of flora, 228,
229, 317-319; Carex and Sphagnum,
332-358, 347-352, 357 ; Sc^vola, 227-
236; Acacias, 167, 171,319; MyrtaceaB,
317; Leguminosae, 318; Eucalyptus,
318, 319; Uncinia, 498-501; as a
source of wide-ransing littoral plants,
171, 192, 207, 228,^229; drift-seeds in
South Australia, 140, 164." See under
West AustraUan Current.

Avena marginata, 411

Avicennia (genus), 309, 454

nitidari81; distribution, 86, 181,

454 ; as a constituent of the mangrove
formation, 4. 10, 15, 90. 100, 106, 108,
109, 202, 203, 283, 289, 290, 452;
represented in stranded beach-drift
and floating estuarine drift. 10, 12, 15,
17, 182. 446; mode of dispersal, 4, 18,
86, 90, 182, 451, 452; effect of drying
on serminating fruit, 182; viviparous
habit, 4, 182

Azevinho. See Ilex perado and I.
azevinho.

AzoUa, 16, 105, 107

Azores :

Author's sojourn, 359; his ascents of
Pico, 360; history of botanical
investigation, 361, 385; heights of
the islands, 364; conditions for
forest -growth compared with those

GENERAL INDEX

507

Azores {continued) —

of Madeira and the Canaries, 366,
385; profile of the mountain of Pico,
365; bluffs of Ribiera grande, 366;
extent of vegetation on Pico, 367,
385 ; the zones of vegetation on Pico,
367, 386; their comparison with
those of Teneriffe and Madeira, 407-
411, 415; prevailing climatic con-
ditions of Pico, 371 ; snow on the
mountain, 372; general account of
the vegetation of Pico, 372, 387;
the summit-plants of Pico, and their
comparison with those of Teneriffe
and Madeira, 370, 372-374, 386, 411,
416 ; vegetation of the upland moors
of Pico, 376, 386; secondary cones
of Pico, 378 ; wells of Pico, 388, 496 ;
lake-district of Pico, 378, 387 ; sanc-
tuaries for plants on Pico, 374, 375,
387 ; extensive Sphagnum region on
Pico, 377.

Bottle-drift on the Azores, 49-55, 64,
68, 460

Firewood in the Azores, 397, 398
Notes on Azorean plants, 425; plants
collected by Forster on Fayal, 491 ;
coast plants of Azores, 218, 219, 384,
388; uplands of San Miguel, 382,
387 ; Terceira, 383, 387 ; species of
Sphagnum in the Azores, 343, 478;
Sargasso weed on Azorean beaches,
485; list of works on the plants of
the Azores, 439
Proportion of native plants of Azores,
389, 414; characters of the original
forests, 391, 414, and the large size
of the trees, 392, 414; large trunks
buried in volcanic ashes, 393, 414;
maximum size of existing trees, 395,
414; causes of the destruction of
the original forests, 396, 414; affini-
tiesof the native flora, 398-411, 415;
distribution of characteristic native
plants, 400; plant-stocking of the
Macaronesian Islands, 411, 416;
derivation of some plants from the
Great Atlas, 405; relation between
the differentiating and dispersing
agencies, 399, 417, 438; modes of
dispersal of Azorean plants, 417, of
those of the woods, 418, 438, of
aquatic and subaquatic plants, 420,
439; of coast plants, 420, 439;
of the plants of the moors, 418,
438; the efficacy of winds in
plant -dispersal, 422, 439; early
cultivated plants of the Azores,
397.

Pumice on the beaches of the Azores,
479

West Indian seeds carried to the
Azores, 27, 37, 122, 158, 181

Babington, on Iceland beach-plants,
187

Baccharis dioica, 285, 292
Bactris, 4, 13

Bahamas, including the extreme south-
eastern islands (Turks, Caicos, etc.) :

Bottle-drift stranded on the islands,
49, 51, 54, 56-58, 61, 62, 64, 71-73,
79, 462^65, 470, 471, 477.

Bottles dropped overboard in their
vicinity or passing near them " en
route," 14, 72, 463, 465, 466, 468,
477. See Turks Islands.

Climate, Aridity of, in past ages; 271,
272 275.

Flora,' 11 7, 168, 192, 198, 202, 210, 224,
225, 284, 290. See Turks Islands
flora.

Geology, 254-276 {see Turks Islands),
502-504; Bahama Banks, 254, 255;
former land connections, 272, 273;
evidence of change in old charts, 264,
275

Bahia, bottle-drift, 71
Bain, on Dracaena draco, 489
Baker, E. G., on Sacoglottis amazonica,
137

Ball, J., on plants of the Great Atlas,

405, 408, 439
Baltic coasts. West Indian seeds, 36
Barbados olive, 286

Barringtonia, 5, 168, 175, 213, 214, 243,
454

Barrow, on drift-wood stranded in high
northern latitudes, 35, 45

Batatas acetossefolia, 217

Bates, H. W., on Amazon drift, 75, 128

Batis maritima, 101, 106, 108, 283, 290-
292, 451-453, 478

Bauhin, C, on the seeds of Ipomcea
tuberosa, 32, 42, 161-163

J., on the fruits of Sacoglottis

amazonica, 42, 137

Beach-drift, West Indian; sources, 1, 3,
18; sorting process and fine drift, 6,
241 ; general description and char-
acters, 2, 6, 18 ; list of plants supplying
it, 5, 6; contrasted with West Indian,
Indian Ocean, and tropical Pacific
beach-drift, 5, 18; selection of the
Turks Islands for the study of its
oceanic transport, 8, 14, 19; compari-
son of beach-drift on the Pacific and
West Indian coasts of tropical America,
17, 19. See also under Jamaica,
Trinidad, Turks Islands.

Beach plants of AVest Indies and West
Africa compared, 87, 88, 91-95

of West Indies. See under Littoral

plants.

sand-rock, 263

Becher, A. B., on bottle-drifts in the
North Atlantic, 46, 50, 57, 66, 81

508

GENERAL INDEX

Beirfto, C. M. F. da, concerning plants
from the Azores, 364, 434, 439^'

Bentham, on plant -distribution, 324, 327,
329, 330. 354; Acacia farnesiana, 166,
171; Cassytha, 191. 193; Chrysobala-
nus icaco, 196; Dioclea reflexa, 131;
Dodonaea viscosa, 206; Mucuna, 121,
459; St, Helena flora, 460; Thespesia
populnea, 244

Bent -stone. See Buesteen.

Berghaus, H,, on bottle-drift, 46, 81

Bermuda; its stranded bottle-drift, 49,
51-54, 62, 65, 466-471; its relation
to the currents, 466-471 ; West Indian
seed-drift on its shores, 38, 139, 158,
468 ; flora, 146, 204, 466 ; geology, 259,
273, 502; supposai continental con-
nection. 466

Beta maritima, 384, 404, 420, 447, 448,
450

vulgaris = Beta maritima.

Bibliographies, or lists of works quoted :
botanical works, at the beginning of
volume; West Indian seed-drift on
European shores, 42; bottle-drift, 81;
geology of the Turks Islands and
Bahamas, 276; current -connections in
southern hemisphere, 312; concerning
plant -distribution, 330 ; plants of the
Azores, 439

Bigbury Bay (South Devon); West
Indian seed -drift, 28, 134

Birds; as seed-dispersers, 32. 175, 192,
198, 252, 291, 294. 354, 418-422. 435,
437, 450, 4.54, 489, 499. 500 ; sea-birds,
32, 294. 421, 499, 500; pigeons, 175,
192, 198, 252, 418, 435,^454, 489;
parrots, 175; wild ducks, 420

and Currents associated in seed-
dispersal, 192, 230, 232, 252

micrration to Africa. 354; to the

West Indies, 500

Biscav, Bay of; stranded bottle-drift
49,52-56. (At least two -thirds of the
bottles included in the tables as re-
covered on the coasts of France and
Spain would be placed under this head. )

Black River. See Jamaica.

Blechnum spicant, 371, 374, 377

Blue Hole. See Jamaica.

" Blue Jacket," figurehead washed ashore
at Fremantle, 296, 298

Boa constrictor, stranded on St. Vincent,
486

Boid, on the ascent of Pico, 361, 372, 439
Bolle, on Junipems oxyeedrus in the

Canaries, 408
Bontia daphnoides (Barbados oUve), 198,

286

Boobies, swallowing seeds of Guilandina

bonduceUa, 32
Boodle' on the character of the timber

of a buried Azorean tree, 395

Borago officinalis, 491

Borgesen, on West Indian seeds stranded
on the Faroe Islands, 35, 42

Borrera thymifolia, 285, 2S6, 288

Borrichia arborescens, 87, 183, 194, 202,
279-283. 286, 289-291, 451, 452

Bottle-drift :

Chapter dealing with, 46-82; drifting
rate=, 6-l:-71 ; summarv, 78; tables,
52, 53, 57, 61, 65, 66, 67, 71, 462, 464,
466, 475; history of the investiga-
tion and sources of materials, 46,
47 ; the value of bottle-drift data,
48 ; proportion of recoveries, 48, and
the associated difficulties, 49 ; tracks
of bottles thrown over together,
49; divergent tracks of derelictfi
and casks, 50
Illustration by bottle-drift of the
distribution by the equatorial cur-
rents of seed-drift over the West
Indies, 72 ; the burden of the Main
Equatorial current, 73; the island
of Trinidad as a centre of seed-drift
dispersal, 74 ; the transport of
Amazon drift to the West Indies,
Florida, and Europe, 75 ; the balance
of the account between the Old and
the New World, 76; drift carried
by currents round Cape Horn, Cape
Agulhas, and the North Cape, 78
Surface-circulation of the North At-
lantic, 51 ; the passage of bottle-
drift from the West Indies to
Europe, 52, and from Europe and
North-West Africa to the West
Indies, 58
The currents of the South Atlantic, 59 ;
the transport of bottle-drift in the
Main Equatorial Current, 60 ; the
South Equatorial and the Brazil
currents, 62; the current -connec-
tions of the South Atlantic with the
Indian and Pacific Oceans as indi-
cated by bottle-drift, 63
The difficulties connected with the
drift -rates of bottles across the
Atlantic, 64; the drift -rates from
the West Indies to Europe, 65, 66;
from Europe to the West Indies,
66, 67, 68; from tropical Africa to
Brazil and the West Indies, 67, 69;
from ofi the Amazon estuary to
Florida, 70, and in the Brazd current,
70 ; general results for the Atlantic,
71

See Africa, Amazon, America, Ant-
arctic latitudes, Antilles (Greater and
Lesser), Antillean Stream, Arctic
latitudes. Ascension, Atlantic, Aus-
tralia, Azores, Bahamas, Bermuda,
etc.

Boulogne, West Indian drift -seed, 28

GENERAL INDEX

509

Bourbon, Island of ; Carex and Sphag-
num, 343-346
Bowlesia, 412

Bracken. See Pteris aquilina.

Brand, J., on turtles stranded on the

Shetland Islands, 40, 42
Brandis, D,, on Arceuthobium oxycedri,

426

Brazil, bottle-drift, 8, 61, 63, 69-71, 76,
474, 475

Brazilian Current, 60, 62, 63, 70, 80, 89

Britton, N. L., on Bahamian and Jamai-
can plants, 9, 106, 205, 284

Broadway, W. E., on Entada scandens
in the West Indies, 118

Brooke, A. de Capell, on West Indian
seeds and mahogany baulks cast on
the Norwegian and Orkney coasts, 25,
34, 35, 40, 43

Brotero, on Myrica faya in Portugal, 434

Brown, A. Samler ; no reference to West
Indian seed-drift on the Canaries, 39 ;
comparison of the slopes of the cones
of Pico and Teneriffe, 366; Juniperus
oxycedrus on Palma, Canaries, 408 ;
ascending air-currents on the Peak of
Teneriffe, 425 ; Mesembryanthemum in
Canaries, 449; submarine freshwater
springs off the Canaries, 497

C. S., on Azorean plants, 218, 359,

364, 384, 385

R., on a Guilandina seed on the

Irish coast, 30

Miss S., on the buried Junipers of

the Azores, 394

Brownson Deep, 258

Bruguiera, 309

Buch, Von, on the zones of vegetation of

Teneriffe, 407
Buchenau, on the means of dispersal of

Juncus and Luzula, 419
Bucida buceras, 16, 17
Buesteen (Bent-stone), 23, 27, 208, 209
Bulimoid shells in aeolian rock in the

Turks Islands, 260
BuUar, H.\, on the Azores, 361, 397,

J. / 398, 440

BuUer, A. H., on the falling rate of

spores, 355, 423
Bullock, on seeds of Entada scandens on

Orkney and Norwegian beaches, 34, 36
Buoyancy of seeds and seed-vessels ;

comparison of behaviour in fresh water

and sea-water, 117, 123, 124, 132, 139;

investigations of Lloyd Praeger, 473
Results of experiments ; West Indian

littoral and estuarine plants, 86, 87 ;

species of Anona, 177; Cakile, 189;

Scsevola, 236; Tournefortia, 251.

Other results, 123, 169, 173, 174, 180,

183, 190, 192, 199, 204, 207-209, 218,

221, 223, 225, 237-239, 242, 247, 421,

428, 447, 449, 450, 456-458. (For

the principles involved, see under
Littoral plants and in my previous
work on Plant-Dispersal.)
Burkill, I. H., concerning Acacia farnesi-
ana, 171, and Thespesia populnea,
246

Burnt-bush. See Euphorbia vaginulata.
Bussu palm, Manicaria saccifera, 128
Butter-nut. See Caryocar nuciferum.
Button-tree. See Conocarpus erectus.
Byronia, 429
Bystropogon, 410, 412

Cabarita River. See Jamaica.
Cabeza Norte (Pico, Azores), 378
Cabral, the Portuguese navigator, 396
Cacoon, 205. See Cocoon.
Cactaceae, 168
Cactus. See Opuntia.
Csesalpinia, 456. See under Guilandina.
bonducella, 139f See Guilandina

bonducella.
Caicos Islands ; bottle-drift, 56, 462-465,

477; flora, 224, 284, 286, 287, 290;

banks on which they lie, 255-258, 290.

See Turks Islands and Bahamas.
Cakile, 87, 184^189, 219, 282, 288, 291,

384, 404, 407, 421, 427, 451, 452
Calabash. See Crescentia.
Calabash-tree. See Crescentia cujete.
Californian current and climate, 272
Callitriche in the Azores, 371, 378, 382,

387, 402, 417, 420
Calluna vulgaris (Ling); in the Azores,

370-374, 376, 377, 379, 383, 386, 387,

398, 402, 411, 427 ; means of dispersal,

417, 419, 422, 425
Calonyction album, 221, 452; synonym

of Ipomoea tuba, q. v.
Calophyllum, 175; C. calaba, 11, 12, 155,

215; C. inophyUum, 155, 156, 454
Calotropis procera, 290
Cambage, R. H. ; on Acacia farnesiana

and other Australian plants, 170, 171,

318, 319, 330
Campanula, in the North Atlantic islands,

428

vidalii, 385, 404, 407, 413, 427,

428

Canadas (Teneriffe), 408, 411
Canarina, 327
Canarium, 454

Canary Islands ; stranded bottle-drift,
48, 52-54, 56, 69, 483, 484; bottles
cast overboard in the vicinity, 57, 66,
67, 68; West Indian seed-drift, 38;
shore plants, 448 ; flora compared with
those of the Azores and Madeira, 365,
368, 369, 385, 398-416; history of
the plant-stocking, 411-413, 416. See
Teneriffe.

Canavalia, 133; C. obtusifolia, 5, 12, 17,
87, 92, 189, 283, 291, 451, 452, 454

510

GENERAL INDEX

Candolle, A. de, 76, 89, 120, 152, 159, 166,

172, 193, 196, 207, 216, 362, 480
Cannaceae, 315

Cape of Good Hope and Cape Agulhas ;
doubling the southern extreme of
Africa by seed and bottle-drift, 39, 62,
63, 78, 81

Cape Horn, doubled by bottle-drift, 63,
78, 81

Cape-pigeon (Daption capensis), as a seed-

disperser, 499
Cape Race. S.'e under Newfoundland

bottle-drift.
Vf-rde Islands ; bottles dropped over

in vicinity, 57^ 6/, 69; Acacia farnesi-

ana, 170; Cassia fistula, 155
Carapa, 141, 228, 309 ; C. guianensis, 3-5,

11-13, 18, 86, 90, 141; C. moluccensis

and C. obovata, 141-143
Cardot, J., the Mosses of the Azores, 440
Carex compared with Sphagnum :

Influence of the divergence of the
continents on their distribution,
332-358; both respond to the same
law, 332; comparison of the East
and West Hemispheres in the north,
335; connections of the South
American Carex and Sphagnum
floras, 335 ; the stream of arctic and
subarctic species down the Andes
to Cape Horn, 337; the Carex
and Sphagnum connections between
South America, Africa, and the
Australian and New Zealand region,
339; the isolation of Africa, 341,
342 ; the outside connections and
sources of the African Peat-mosses
and Carices, 344-346; Sphagnum
and Carex in Australia and New
Zealand, with their Asiatic and South
American connections and the bridg-
ing over of the gap in Malaya, 347-
353; the insular factor, 343; the
distribution of the Carices by birds
and of the Peat-mosses by winds,
354; summary, 355. See also Mrica,
South America, Australia, etc.
Carex acutiformis, 342, 345, 346; brun-

nea, 345, 350 ; breviculmis, 350, 351 ;

canescens, 338, 339, 352 ; cernua, 345,

346, 349; darwinii, 340, 349, 352;

divisa, 342, 345, 346; extensa, 342,

345, 346; flava {see note below), 371,
380, 381, 387, 402, 420 (included here
amongst the subaquatic plants, though
it is also abundant in the wet moors) ;
lagopina, 351, 352; macloviana, 338,
339; microglochin, 338, 501; oederi
{see note below), 339, 341, 345, 346,
349, 351, 352; cederi, var. cataractae,

346, 351; pseudo-cyperus, 339, 342,
351, 352 ; pumila, 339, 340, 351, 352 ;
steUulata, 351, 371, 375, 378, 387, 403

(its fruits float for a year and more
and occur in the floating drift of ponds ;
the plant's name should be associated
with Carex flava on p. 420); trifida,
340, 349, 352 ; vulpina, 342, 345, 346.
(Single references to many other species
will be found on pp. 338-352.)

Note. — Carex cederi, regarded by
Bentham and Hooker as a form of the
Linnean species, C. flava, is separated
by Kiikenthal. Both are European
and North American; but C. cederi,
in the form of var. cataractse, extends
to the southern hemisphere (Chile,
Patagonia, South Africa, Tasmania,
New Zealand).
Caribbean Sea; traversed by bottle-
drift and seed-drift brought by the
equatorial currents from off the West
African coasts, the Amazon estuary,
Brazil, the Guianas, the Orinoco, etc.,
58-61, 73, 75, 444, 445; bottle-drift
from the Caribbean Sea to Europe, 59,
76 ; minghng in this sea of drift brought
by the north and main equatorial
currents from African and South
American waters, 62, 73
Carreiro, Bruno T., on the Azorean flora,

359, 364, 385, 427
Carthamus tinctorius (Safflower), 492
Caryocar nuciferum (Butter-nut), 28, 30
Cashew-nut. See Anacardium occiden-
tale.

Casks, drifted by currents, 50, 76, 81, 299,
481

Cassia fistula, 6, 11-13, 28, 36, 162; C.

grandis, 4, 11, 13, 16, 152
Cassytha, 171, 207; C. filiformis ( =

americana), 87, 92, 191
Castillo, Drake del; on Pacific Island

plants, 157, 171
Catesbcea, 287

Gates by, M. ; on Genipa clusiifolia, 210 ;
on the Manchineel of the Bahamas,
286 ; on the iguanas of the Bahamas,
487

Cattegat, fruits of Calluna vulgaris, etc,

blown across, 425
Cattle, spreading the seeds of Acacia

farnesiana, 169, and those of Pithe-

colobium saman (Morris in " Nature,"

March 15, 1888).
Cauliflory, 147, 211

Cayman Islands; seed-drift and bottle-
drift brought by the equatorial currents,
8, 61, 76, 130, 145; electric-light bulbs,
165; Guilandina, 138, 456; Cakile,
186; Cassytha, 192; Coccoloba uvi-
fera, 197; Conocarpus erectus, 201;
Ipomoea carnosa, 218, and I. tuba, 221 ;
Mammea americana, 145; Morinda
royoc, 225 ; Sophora tomentosa, 237 ;
Suriana maritima, 240; Tournefortia

GENERAL INDEX

511

gnaphalodes, 250 ; Vigna luteola, 251 ;
Paseiflora ciiprea, 289; Dodonaea vis-
cosa, 206

Ceara (Brazil), bottle-drift, 8, 76, 130
Cedar, Cedro. See Juniperus oxycedrus.
Cedrela odorata, 111
Cedronella, 410, 412

Cenchrus echinatus, 282, 291 ; C. tribu-

loides, 85, 451-i53
Cerastium tetrandrum, 411
Ceratophyllum demersura, 16, 104, 105,

107

Cerbera odollam, 5, 168, 454
Chaparral scrub, 168, 169, 229
Charms, West Indian drift-seeds as, 22, 24
Chastenet-Puysegur, De; old chart of

some Bahama shoals, 264
Chatham Islands ; Carex and Sphagnum,

348, 349, 352; Uncinia, 498; cask

drifted from the Macdonald Islands,

299

Chaves, F. A., concerning the Azores,

359, 364, 365, 394, 396, 440
Cheeseman, T. F., 171, 220, 246; on New

Zealand weeds, 391
"Cherokee," s.s. ; bottles thrown ov^er-

board from, 49, 65, 465, 467
Chile, North; influence of Humboldt

Current on climate, 271, 272, 275
Chimborazo forests, 212
Christ, D. H., on the Canarian flora, 406-

408, 412, 440, 487
Chrysobalanus, 83, 181, 193-196, 204,

326; Chr. pellocarpus, 193
icaco (Coco-plum), 5, 12, 87, 92,

151, 179, 181, 193, 197, 205, 207
Chrysodium vulgare (Swamp Fern), 105
Cladium, 179, 455

Clarke, C. B., on Ipomoea kentrocaulos,
161

Claussen, P., on West Indian seeds on
Scandinavian beaches, 21, 23, 34, 35,
41, 43

Claw-grass, 453

Clerk, W., on a West Indian seed from

the Orkneys, 163
Clerodendron, 175
Clethra, 408, 410, 412
Climate, aridity and cold currents, 271,

272, 275

Clusius (De I'Escluse), concerning West
Indian drift seeds, 20, 32, 41, 43, 45,
137, 161, 162

Coccoloba, 197-200; C. laurifolia, 198

uvifera (Seaside-grape); general

treatment, 197-200; distribution, 87,
197; station, 109, 116, 168, 194, 197,
198, 200, 206, 210, 237, 244, 279, 283,
286, 288, 289 ; means of dispersal, 87,
94, 195, 198-200, 291 ; fruits in beach -
drift, 5, 12, 198, 446

Cockayne, on Dodonaea viscosa in Isew
Zealand, 207

Cocoon, 16, 30, 31, 34. See Entada

scandens.
Coco-plum. See Chrysobalanus icaco.
Cocos nucifera (Coco-nut), 28, 29, 35-37
Codeso (Adenocarpus viscosus), 408
Coix lachryma, 106
Cole, Grenville, on dune sand, 495
Colon, beach drift, 6, 13, 14
Colubrina, 200; C. asiatica, 5, 85, 87,

92, 200

Columba livia, in Azores, 418; C.

palumbus, 418
"Columbian Navigator." See Purdy.
Commelyna, 106, 107
CompositaB, dispersal by winds, 424, 426,

439

Congo, a source of seed-drift for the New
World, 39, 74, 81

Conifers, Mesozoic, 328

Conocarpus erectus (Button-tree) ; general
treatment, 201; variety, 202, 279;
distribution, 87, 95, 201 ; station, 5, 10,
105, 109, 168, 197, 200, 201-203, 206,
244, 279, 280, 283, 289, 451, 452; dis-
persal by currents, 87, 92, 93, 95, 203,
204, 291, 452 ; in beach-drift, 5, 12, 17

Convolvulus acetosaefolius, 217; C. sol-
danella, 217, 220, 294, 307, 308, 311

Coppinger, Dr., on the long flight of the
Cape-pigeon, 499

Corals; floating, 164

Corchorus hirsutus, 278, 280, 286, 291,
446, 478

Cordeiro, old writer on the Azores, 393
Cordia, 175

Cornwall ; West Indian seeds on beaches,
28, 45, 123; Cakile, 186, 188

Cotula; dispersal by sea-birds, 294

Cotyledon umbilicus, 422

Coutinho, A. X. P., Cape Verde plants,
170, 449, 488

Cow-itch (Mucuna pruriens), 457, 458

Cozumel Island (Yucatan), bottle-drift,
466

Crantz, on drift-wood in high northern

latitudes, 45
Crassulacese, in Canary Islands, 408
Crepis virens, 492

Crescentia, 145-150; gourds probably
carried to European shores, 25, 26, 36,
146

cucurbitina (Paki), 3, 11, 13, 15-17,

86, 91, 145-150
cujete (Calabash-tree), 3, 11, 13,

15-17, 86, 91, 145-150
Crmum, 3, 15, 16

Crithnum maritimum, 384, 388, 404, 418,

421, 448, 449
Crocodiles, stranded on Keeling Atoll,

303, 486. See Alligators.
Crospunk, the Hebrides name for Entada

scandens, 25
Croton hjalmarssonii, 286

512

GENERAL INDEX

Crudya, 83, 84, 204, 206, 326 ; Cr. spicata,

3, 16, 86, 90, 106, 204
Crueger, Dr., on Sacoglottis amazonica,

134

Cryptogams. See Spores.

Chiba; seed-drift brought by the equa-
torial currents, 8 ; bottle-drift, 52, 56,
58, 61, 463, 466; forest-trees, 112, 117,
215; submarine fresh-water springs,
497

Gucurbita, 145 ; C. lagenaria, 146
^ulcita fern. See Dicksonia culcita.
Currents, as illustrated by bottle-drift.
See under Bottle-drift, Atlantic, Aus-
tralia, Equatorial Currents, Gulf
Stream, Indian Ocean, Pacific Ocean,

(cold) and aridity, 271, 272, 275

Gycas circinalis, 5

Cyperacese, 105, 106, 109, 353

Cyperus, 15, 353; C. brunneus, 85, 278-
281, 291, 451, 453; C. compressus,
491 ; C. elatus, 105, 106 ; C. esculentus,
491, 492

Dabney, American Consul-general in the

Azores, 362, 372
Dahl, F., on the arctic centre of dispersal,

325

Dana, J. D., Bahamian geology, 255, 262,
263, 276

Daphne; dispersal by birds, 417, 418;

D. gnidium, 405
laureola, 370, 374, 375, 386, 392,

401, 405, 428
Daption capensis (Cape-pigeon), 499
Darrell, J. H., on Bermudian plants,

197

Dartmoor vegetation, compared with that
of the moors of Pico, 371, 376, 386

Darwin, C. ; petrels of St. Kilda swallow-
ing West Indian drift -seeds, 32 ; West
Indian drift-seeds on the Azores, 37,
122; plants of Keeling Atoll, 170, 448;
coral reef theory, 255; dispersal of
plants from the north, 327 ; Darwinian
evolution, 319, 322

Datura stramonium, 290

Daussy, on bottle-drift, 46, 69, 81

Davey, F. Hamilton, on seeds of Entada
scandens on the Cornish coast, 28

Davis, Ainsworth, quotation cited con-
cerning currents, 39

Strait; bottle-drift, 55, 79, 484,

496; casks from a wrecked ship, 50.
See Greenland.

Dayssy. See Daussy.

Deane, H., on the Tertiary flora of
Australia, 318

Debes, L. J., on the occurrence in the
Faroe Islands of the seeds of Entada
scandens, 21, 23, 33, 34, 41, 43

Decaisne, J., on Mucuna pruriens, 458

DefEarges, M., bottle-drift on the Cftiilian

coast, 300
De I'Escluse, 20. See Clusius.
Denmark; West Indian seeds on the

coast, 27, 36, 37 ; bottle-drift, 63
Derelicts and currents, 48, 50, 68, 69, 72,

472, 473

Descourtik, on Calophyllum calaba, 156
Desmanthus, 326

Deutsche Seewarte, bottle-drift, 47, 64,
66, 74, etc. See under Schott.

Devonshire; seeds and fruits from the
West Indies and elsewhere in the
beach-drift, 28-30, 123, 134; pelagic
organisms stranded, 29; Cakile mari-
tima, 185, 188

Dicksonia culcita, 370, 375, 380, 382,
383, 428

Dieffenbachia seguine (Dumb-cane), 107
Differentiation theory, 313-322, 323, 329
" Difficult " plants. See Problem plants.
Dildo, name of a species of Opuntia, 278,
287

Dimorphandra mora, seeds in beach-
drift, 12, 13

Dioclea, 133; D. guianensis, D. pana-
mensis, D. violacea, 132; D. reflexa,
4, 7, 11-13, 25, 26, 33, 34, 86, 91, 130,
455

Dioscorides, on the small Acacia, 172
Distribution ; its controlling factors, 323-

330 ; discontinuity, 83, 94, 326, 330.
Dixon, C, on Brazilian drift seeds in the

Fulmar petrel, 32
Dodon^a, 171, 193

viscosa, 86, 92, 109, 198, 206, 237,

286, 288, 291; variety, D. burmanni,
109, 206

Dolichos urens (= Mucuna urens), 32, 35
Dondia, 453

Donkey-eye bean (Mucuna urens), 458
Dracaena aurea, 487-489 ; D. ombet, 488

draco (Dragon-tree), 408, 410, 412,

487

Drepanocarpus lunatus, 11, 86, 88, 90,
159

Drew, on denitrifying bacteria, 502
Drift-wood, in high latitudes in the North

Atlantic, 35, 40, 45
Dripping cliffs in the Azores, 497, 498
Droseraceae, 315

Drouet, H., on the Azorean flora, 359,
363, 368, 382, 383, 385, 394, 418, 428,
432, 435-437, 440

Druce, G. C, on Campanula vidalii, 427;
on other Azorean plants, 364, 434, 440

Drude, O., on southern floras, 294

Ducks, Wild, as seed-dispersers, 420

Dumb-cane, 107

Dwarfing of trees and shrubs; in the
Azores, 367, 373, 374, 382, 386, 387,
428-432, 437; in the Turks Islands,
202, 279, 283, 446

GENERAL INDEX

518

Dyer, W. T. Thisolton; theory of centre
of dispersion in the north, 323-330,
332; evidence supporting it in this
work, Anona, 181, Chrysobalanus, 181,
196, Cakile, 187, Morinda, 226, Ximenia,
263, Carex and Sphagnum, 353

Eagle-stones, Norse name for West Indian

drift seeds, 21
Easter Island plants, 156, 246
Ecastaphyllum in Turks Islands drift,

genus doubtful, 111
brow-nei, 5, 11, 12, 14, 17, 87, 88,

92, 95, 159, 194, 197, 207, 244
Echites, 287
Echium, 408
Ecuador :

Beach-drift, 17, 145, 182, 190, 209;
beach flora, 191, 203, 227; infiltra-
tion of sea-water landward, 101 ;
Rhizophora, 99

Guayas or Guayaquil River; floating
drift in the estuary, 3, 17, 145, 179,
182, 209, 212, 222, 252; vegetation
of estuary, 99, 178, 180, 222;
salinity, 100, 180 ; underflow of sea-
water in the estuary, 102
Eggers, von, on West Indian plants, etc.,

98, 201, 203, 217, 227
Elaeocarpus, 489

Electric-light bulbs in beach-drift, 165

ElUot, G. Scott; on Cassytha fiUformis,
192 ; on Juniper growth, 430

" Ely " (whaler), drift of a cask, 299

EnaUagma cucurbitina, 147

England; bottle-drift, 52, 53; West
Indian drift seeds, 26, 28, 45, 123, 134

Engler, A., southern floras, 294

English, T. M. Savage; seed, bottle, and
other drift on the Cayman Islands, 8,
76, 130, 145, 165; Ipomoea acetosse-
folia, 218; Sophora tomentosa, 237;
Passiflora cuprea, 289

Entada, 83, 118, 120, 133; E. poly-
stachya, 118

scandens seeds (Cocoon); general

treatment, 86, 91, 117; in West Indian
beach-drift, 4, 6, 11-13, 17, 117, 118;
in European beach-drift, 22-28, 30-36,
42, 45 ; in Azorean beach-drift, 37, 38 ;
in river-drift, 4, 119; drift seeds used
as snuff-boxes in Europe, 25, as tinder-
boxes in the Hebrides, 25, and for
medicinal purposes, 24; superstitions
concerning the drift seeds in Europe
and the popular names given to them,
21-25

Epilobium ; dispersal by winds, 423—425,
439

Equatorial currents of the Atlantic :
Counter Equatorial, 59, 77, 89, 91, 93,
94, 235, 301, 476. See under Guinea
current.
L L

Main Equatorial; differentiated from
the South Equatorial, 60, 79, 474;
indications of bottle-drift, 8, 58, 59-
62, 67, 69-76, 79, 80, 442-446; as
a carrier of seed-drift, 7, 8, 72-78,
81, 84-89, 94; bearing Amazon
bottle and seed drift to the West
Indies, 7, 8, 70, 75, 76, 81, 444-446;
carries to the West Indies the sweep-
ings of both sides of the South
Atlantic, 73, 74, 81; mingling of
its drift with that of the North
Equatorial in the Caribbean Sea, 62,
73, 81

North Equatorial; indications of
bottle-drift, 51-60, 57-59, 67, 69,
71, 72, 73-76, 79, 80

South Equatorial; 59, 60, 62, 80, 474.
See above under the main current.
Equatorial currents of the Indian Ocean ;

indications of bottle-drift, 301-307,

311

Equatorial currents of the Pacific Ocean ;
indications of bottle-drift, 297, 298,
310

Erica arborea, Canarian and Madeiran

Tree-Heath, 406-408, 410
azorica, Azorean Tree- Heath, 369,

370, 373-379, 382, 386, 392, 394-396,

398, 401, 422, 428
cinerea, 411; E. scoparia, 491;

E. tetraUx, 425
Ernodea littoralis, 85, 291, 453
Ernst, A., on the re-stocking of Krakatau,

116, 142, 154, 190, 207, 425, 458
Erodium, 390

Erslev, on tropical seeds on the Jutland

coast, 37, 43
Eryngium maritimum, 447
Erythraea centaurium, 491 ; E. maritima,

404; E. massoni, 371, 374, 377, 379,

387, 402 ; E. ramosissima, 491
Erythrina, seeds in European drift, 23,

25-27, 33, 208 {see Buesteen, the

Norse name); E. corallodendron, 209;

E. velutina, 209
Estuaries; plants, 86, 88, 90, 94 {see

Mangroves); salinity and its influence

on station, 99-104, 110, 180; under-

flow of sea-water, 102, 110
Etna, subterranean and submarine

streams, 497
Eucalyptus, the question of its Australian

origin, 318, 319, 322
Eucarex, 345
Eugenia, 318, 454

Euphorbia azorica, 384, 388, 404, 407,

421, 428. See E. pinea.
buxifolia, 86, 279-283, 288, 291, 451,

452

canariensis (Cactoid Euphorbia)

408, 412, 448
lecheoides, 286

514

GENERAL INDEX

Euphorbia mellifera (Tree- Euphorbia),
401, 407, 410, 428. See E. stygiana,
its Azorean form.

origanoides, 460

parahas, 448-450

peplis, 219, 384, 388, 404, 421

pinea, 384, 388, 404. See E.

azorica.

• piscatoria, 410

polygonifolia, 186

stygiana (Tree-Euphorbia), Azorean

variety of E. mellifera {see above), 370,
374, 375, 379, 386, 392, 401, 428

trinervia, 460

vaginulata (Burnt-bush), 198, 280,

281, 283, 285, 288, 289
Euphrasia grandiflora, 375
Europe :

Bottle-drift, 46-82 ; from West Indies
to Europe, 52-55, 59, 65-68, 71, 76,
79, 80; to the West Indies from
Europe, 56-59, 66, 68-69, 71, 79,
80; from the African side of the
Atlantic to Europe, 59, 76; from
ofE the Amazon estuary, 70, 71, 75;
from Ascension, 76, 482

West Indian seeds and fruits on
European beaches, 20-45; baulks
of mahogany washed ashore, 35, 40,
42, 48, 78
Euterpe, 16

Evans, Lieut., on Sargasso weed in the
Florida Stream, 485

Ewart, A. J. ; on seeds of Guilandina
bonducella and Mango stones washed
ashore on south coasts of Australia,
140, 164; on the seeds of Canavalia
obtusifolia, 190; on Convolvulus sol-
daneUa in Australia, 220

" Extensionists," their views, 272, 273,
275

Faba marina, name of Entada seandens,21

orcadensis, name of Ipomoea tube-

rosa, 161, 163

Fagus, 294, 326, 328, 433

Fairies' Kidneys, a Norse name for the
stranded seeds of Entada scandens, 23,
25. See Vette Nyre.

Falkland Islands, bottle-drift, 63, 74, 78

Families of plants; grouped into Primi-
tive and Derivative families, 314-316,
321 ; their evolution, 319, 322

Farewell, Cape, Greenland, bottle-drift
from the vicinity found on Teneriffe,
483, 484, 496, and near the North Cape
of Norway, 495

Faroe Islands, West Indian seeds
stranded, 21, 23, 25, 27, 34, 122;
drift-wood, 40 ; current-connection
with Iceland, 187

Fawcett, W., on Jamaican plants, 178,
185, 193, 194, 197, 198, 200, 253

Faya, name of Myrica faya, q.v., 433, 434

zone, on Pico, 369, 386

Fayal, origin of name, 433, 434
Fernando Noronha; drift seeds, 121;

Acacia farnesiana, 170; Canavalia

obtusifoHa, 191 ; Ipomoea tuba, 220
Fernow, on Cuban trees, 112, 215
Ferns. See Acrostichum, Asplenium,

Dicksonia, Hymenophyllum, Osmunda,

Pteris, Trichomanes, etc.
Fevillea cordifolia (Antidote Vine), 3, 7,

11, 12, 13, 15, 16, 86, 90, 124
Ficus, 454

Field Columbian Museum, 9, etc.
Fielden, H. W., on a drift seed in the

Hebrides, 24, 32, 43, 162
Fiji, 142, 146, 191 ; Rhizophora, 96-100
Finmark, West Indian drift seeds, 35, 36
Fire-shrub, 285
Firewood, in Azores, 397, 398
Flores, Azores, junipers, 395, 397
Florida region :

Bottle-drift; stranded in this region,
51, 57, 58, 61, 67, 70-73, 75, 79, 444,
445, 463, 466; dropped overboard
in this region, 52, 54, 58, 59, 65, 66,
71, 75, 467, 468, 471
Flora, 93, 106, 114, 178, 179, 192, 194,

210, 220, 225, 252
Geology, 258, 503
Sand-keys, plants. See Lansing.
Seed -drift from the Amazon and
Orinoco, 7

Fogh, C, West Indian drift on European

beaches, 20, 36, 41, 43, 481
Forbesian hypothesis, extension of

Europe, 389
Forster, G. ; plants of Fayal, 361, 385,

389, 433, 440, 491; plants of Easter

Island, 156, 246, and of Cape Verde

Islands, 170
Foula Island (Shetlands), absence of

West Indian seed-drift, 34
Fox, J., West Indian seeds, etc., in the

Shetland Islands, 34, 40, 162
France; West Indian seeds stranded,

26, 28; bottle-drift, 52, 53, 68. See

Biscay.
Frankenia, 388, 448-450
Fredholm, stranded coco-nuts on the

Lofoten Islands, 37
Frigate-bird, seed -dispersal, 32, 279
Fructuoso, on the original woods of the

Azores, 393
Fuegia ; Carex and Sphagnum, 337-341,

352; Uncinia, 498-501; bottle-drift

and its bearing on dispersal of seed-

drift, 63, 74, 78, 294-312, 294-296,

301, 306, 310
Fulmar Petrel, swallowing West Indian

drift seeds, 32
Furnas Valley (Azores), 496 ; trees buried

in volcanic ashes, 383, 394

GENERAL INDEX

515

Galapagos Islands, their plants, 176, 201,

227, 236, 400
Garcinia mangostana (Mangosteen), fruit

on Scandinavian coast, 28, 36
Gastridium lendigcrum, 491
Genipa clusiifolia (Seven-year Apple), 87,

194, 197, 198, 209, 279-283, 287, 291,

487

Gentiana centaurium, 491
Geraniaceae, 315, 316
Geranium, 315; weeds in Azores, 390,
391

Glacial period and plant distribution,

326, 327
Glaux maritima, 187
Glossopteris flora, 328
Gnaphalium luteo -album, 492
Goats; destructive of young plants in

the Turks Islands, 139, 231, 232, 277,

281 ; dispersers of Manchineel seeds,

115

Godman, F. du C. ; on the Azorean flora,
359, 362, 364, 367, 385, 390, 392, 399,
440 ; on the snow-cap of Pico, 367, 372

Gomes, B. A., concerning plants from
the Azores, 364, 434, 440

Goodeniaceae, as an Australian family,
227, 228, 314, 317

Gosse, P. H., on Jamaican pigeons and
Anona dispersal, 175

Gourds, in Scandinavian beach-drift, 36,
146. For general details see under
Crescentia, 145, etc.

Grand Canary, strand plants, 448

Grant, Ogilvie ; on the vegetation of the
higher slopes of Pico, 367; on the
Juniper trees of San Jorge, 396; on
the Azorean pigeons, 418; on missel-
thrushes in the Azores, 437

Gray, Asa; Cakile, 184; plant -distribu-
tion, 327, 329, 330

Great Lakes of North America, shore
plants, 186

Greenland, West Indian seeds and logs
of mahogany, 35, 40, 42. 8ee Davis
Strait and Cape Farewell for bottle-
drift, etc.

Greenman, Dr., on a new species of

Morinda, 226
Grenada; beach plants, 116, 245;

stranded seed -drift, 6, 13; Grand

Etang, the lake and its plants, 131,

455
Grias, 212, 213

cauliflora (Anchovy Pear), 3, 6, 7,

12, 14-17, 86, 90, 106, 124, 147, 205,
211

Grisebach, A. H. R. ; on West Indian
plants, 114, 116, 118, 121, 143-147,
150, 152, 156, 157, 161, 201, 202, 205,
210, 211, 218, 225, 227, 250, 251, 285,
294, 457^59

Guayas or Guayaquil River. See Ecuador,

Guernsey, bottle-drift from Ascension, 76,
81, 482

Guettarda, 175, 287, 454

Guianas; distribution of estuarine drift,
13, 19, 74; bottle-drift, 61, 73-75;
Carapa, 141, 142

Guilandina (genus), 133; seed buoyancy
and an inland station, 456

bonduc (Yellow Nicker), 12, 32, 87,

92, 140, 456

bonducoUa (Grey Nicker) :

Distribution and dispersal by currents,

87, 92, 138, 139, 291
General treatment, 138
Seeds ; in beach drift, West Indian, 5,
10-12, European, 23-28, 30-36,
Azorean, 37, 38, and Australian, 140 ;
drift seeds used medicinally and as
charms, 24; swallowed by sea-birds,
32 ; trade in the seeds, 140 ; buoy-
ancy, 87, 139, 456, 457
Station, 138, 194, 197, 200, 244, 245,
287, 288

melanosperma, 456

species not identified ; seeds in

Trinidad beach-drift, 13, 457; plant
in Jamaican forests, 457

Guinea Current, 59, 77, 475

GuK of; bottle-drift, 67, 71, 74, 76,

80, 81 ; casks drifted to Norway, 481

GuM Nut, name of West Indian seeds on
European beaches, 22

Stream ; early reference to it as a

seed-carrier, 21, 33 ; ancient course
across Florida, 93; bearing West
Indian seeds, 1, 7, 20, 21, 26, 29, 33,
37, 89 ; the indications of bottle-drift,
51-55, 58, 65, 66, 68, 71-81, 466-^71,
482-484

Weed. See Sargasso.

Gulls, Sea, as seed-dispersers, 421

Gumprecht, T. E. ; on drift -products of
the currents in the North Atlantic, 20,
36, 40, 41, 43, 45, 481; old Scandi-
navian names of stranded West Indian
seeds, 23, 209

Gunnerus, J. C, on the tropical seed-
drift of the Scandinavian coasts, 22,
35, 36, 41, 43, 146, 153, 173

Guthnick, the Azorean flora, 359, 362,
385

Gygax, a Swiss mineralogist who visited
the Azores, 362

Haacke, W., polar origin of faunas, 325
Habenaria, 375, 377 ; capacity for wind

dispersal, 424, 425
Haiti. See Hispaniola.
Halophytes, 478 ; Turks Islands, 290
Hammerfest, drifting of casks from the

Gulf of Guinea, 481
Hammocks of the Florida vegetation, 93,

114, 225

516

GENERAL INDEX

Harrison, Prof., on the lake of the Grand
Etang in Grenada, 455

Harshberger, J. W., 331 ; Ambrosia in
North America, 173; Anona palustris
in South Florida, 175-179; Arceutho-
bium in North America, 426; Wood-
wardia growing in Sphagnum tussocks,
378; Bahamas, 192; Bermuda, 206;
Cuba, 215, 253; Florida, 114, 157, 175-
179, 194, 210, 225; Jamaica, 17, 168,
211, 243; Turks Islands, 287; Virgin
Islands, 116, 244, 457; other West
Indian islands, 119, 151, 202, 250;
Lower CaUfornia, 201, 218, 227;
Mississippi delta and Louisiana coast,
191, 218, 252; Texas and Mexico, 167,
168, 229; southern migration of North
American plants, 336; the sunken
Caribbean lands, 152, 213 ; centrifugal
dispersion from the north, 327; salt-
marsh and estuarine plants of New
Jersey, 100, 104, 110

Hart, J. H. ; Herbarium List of the
Trinidad flora, 118, 212, 251; Saco-
glottis amazonica, 7, 134; Entada
scandens, 118; Fevillea cordifolia, 126;
Grias cauliflora, 212 ; Ipomoea carnosa,
218; Thespesia populnea, 244; Vigna
luteola, 251

Hartert, E., on the pigeons of the Azores,
418

Hartung, G., 363, 385, 440; buried
Juniper trees, 392, 394

Hatteras, Cape; bottles thrown over in
its vicinity, 49, 50, 52, 54, 55, 65, 66,
78, 467, 468; derelicts from this
neighbourhood, 50, 72, 472, 473;
turtle carried past in the Gulf Stream,
41

Hawaii ; Acacia farnesiana, 167, 169-171 ;
Ipomoea carnosa, 218; Cassytha fili-
formis, 191 ; Carex and Sphagnum,
343, 345; Dracaena aurea, 487-489;
transport of spores only by winds to
this group, 354, 355; ascending air-
currents on Mauna Loa, 425; sub-
marine streams of fresh water, 497;
Azorean and Hawaiian floras compared,
399, 400

Heather, W., old chart of the Azores, 366
Hebrides; stranded West Indian seeds,
22-26, 31, 32, 122; derehcts, 50, 68,
472, bottle-drift, 52, 53, and turtles,
40^2

Hedera, dispersed by birds, 417, 418
canariensis ; in Azores, 369, 376,

392, 401, 429; in Canaries, 406
Hedley, C, palseographical relations of

Antarctica, 294, 309, 312, 328, 330, 331
Hedyotis adscensionis, 460
Heer, 0., 329, 363

Heilprin, A., seolian rocks in Bermuda,
259, 262

"Hekla," H.M.S., bottle-drift in high

northern latitudes, 484, 496
Heliotropium, 449 ; H. curassavicum, 278,

291, 477

Hemsley, W. B., 43, 294, 440; West
Indian beach-drift, 12, 13, 126, 128,
143; West Indian seeds on European
beaches, 21, 24, 42, 146, 153, 154, and
on Azorean shores, 37; dispersal by
currents, 158, 187, 193, 204, 447, and
by birds, 198, 252; Arceuthobium,
426 ; Bermudian flora, 466 ; Ascension
and St. Helena floras, 459, 460;
Ipomoea tuberosa, 24, 161, 162; Sem-
pervivum in Canary Islands, 408;
Mucuna pruriens, 458; Weeds, 391;
Uncinia, 498-501 ; miscellaneous plants,
116, 147, 156, 157, 160, 167, 171, 201,
225, 227, 246, 250, 251, 488

Henriques, Prof., buried Juniper trees in
the Azores, 395; Myrica faya in Por-
tugal, 433, 434; the popular Azorean
name of Myrsine africana, 434

Hensen, experiments on currents in Kiel
Bay, 50

Henslow, J. S., plants of Keeling Atoll,
448

Hepaticge, in Azores, 375, 383

Hepworth, W. W. Campbell; southern
pelagic organisms stranded in the
south of England, 29; Labrador Cur-
rent, 272; Sabine's casks of palm oil,
482; Gulf Stream, 43

Heritiera littoraUs, 5

Hernandia peltata, 454

Herpestis moimiera, in the West Indies,
105, 477

Hibiscus elatus, 16, 214

tiliaceus, 5, 6, 17, 87, 92, 116, 168,

170, 172, 178, 214, 245-247

Hill, A. W., Arceuthobium oxycedri in
the Azores, 426

Hillebrand, W., Acacia farnesiana in
Hawaii, 167-171; other Hawaiian
plants, 218, 246, 458, 478, 488

Hillier, J. M., Sacoglottis amazonica, 28,
134

Hippocratea, in Trinidad beach-drift, 13

Hippomane mancineUa (Manchineel) ;
beach-drift, 5, 11-14, 17, 115; dis-
tribution, 87, 88, 93, 113, 114; dis-
persal by currents, 87, 88, 93, 95, 113,
115; station, 93, 114, 194, 244, 245;
doubtful identity of the tree in the
Bahamas, including Turks Islands, 286

Hispaniola (San Domingo and Haiti);
bottle-drift, 56, 58, 61, 62, 65, 462,
463, 465, 477; Acacia farnesiana, 167,
168; old masonry on coast, 491

Hjalmarsson, J. A., flora of Grand Turk,
185, 283, 286

Hoban, M. A., West Indian seeds on
Irish coast, 31

GENERAL INDEX

517

Hochstetter, C. (father and son) ; on the
Azorean flora, 359, 362, 363, 365, 370,
376, 385, 389, 392, 428, 440, 491, 492;
zones of vegetation of Pico, 368, 376 ;
vertical ranges of plants, 362, 363, 376,
425, 428-430, 432-438

Hog-Gum tree. See Symphonia globuli-
fera.

Hog-Plum. See Spondias lutea
Hollies. See Ilex.

Honduras; bottle-drift, 57, 58, 61, 75.
See Central America, Nicaragua, and
Yucatan.

Hooker, J. D. ; dispersal of plants from
the north, 324, 327, 329, 330, 354;
southern floras, 294 ; plant-stocking of
the Macaronesian islands, 411, 412;
insular floras, 440; Kerguelen, 500;
St. Helena, 460; West Indian drift
seeds on the Azores, 37; Dracaena
draco, 488; Chrysobalanus icaco, 196;
Conocarpus erectus, 204; Portulaca
oleracea, 478; St. Kilda petrels and
drift seeds, 32

W. J., Niger flora, 99, 131, 194, 196

Horn, Cape; bottles and figurehead
drifting from off the Horn to Australia,
49, 63, 295, 296, 298; doubling of the
Horn by bottle-drift and probably
seed-drift, 63, 74, 78, 81, 300

Home, J., Fijian plant, 171

Horse-eye Bean (Mucuna urens), 34,
458

Hubbard, Mrs., fruit of Sacoglottis

amazonica on the coast of Devonshire,

28, 134, 136
Humboldt, F. H. A. von; West Indian

seed-drift in Europe, 20, 41, 43;

ascending air-currents in the Andes,

425 ; submarine springs off Cuba, 497
or Peruvian Current, influence on

the climate of North Chile and Peru,

271, 272, 275
Hunt, Carew; plants of the Azores, 359,

363, 385, 427, 435, 440 ; trees buried in

volcanic ashes, 394
Hydrocotyle umbellata, in Jamaica, 104,

105, 107

vulgaris, in Azores, 360, 371, 377,

379-381, 387, 402, 417, 429
Hymenaea courbaril (Locust-tree); pods

in the foreign drift of the Turks Islands,

11, 140

Hymenomycetes. See Mushrooms.
Hymenophyllum tunbridgense, in Azores,

375, 379, 387
Hyoscyamus albus, in Azores, 384, 388,

404, 421

Hypericum, 410; H. fohosum, 369, 392,
400, 429; H. grandifolium, 400, 407;
H. humifusum, 492; H. perforatum,
492

Hypochoeris radicata, 492

lanthina shells on English, 29, and
Azorean beaches, 38

Iceland ; stranded West Indian seeds and
mahogany logs, 35, 40, 42; stranded
bottle-drift, 52, 53, 495; shore-plants,
187; current-connections, 187

Iguanas ; in the Turks Islands, 486, 487 ;
as seed-dispersers, 175, 178, 210, 211,
291

Ilex, 406, 408, 417, 418, 429; I. azevinho,
407

perado, 369, 370, 373-375, 378, 386,

387, 392, 398, 400, 406, 407, 429; at
great altitude in Azores, 373

Inagua Islands (Bahamas); plants, 168,
284, 286, 287, 290 ; bottle-drift, 464

Indian Nuts, old name in Scotland for
West Indian drift seeds, 23, 24, 31

Ocean ; its traverse by seed -drift as

illustrated by bottle-drift, 47, 50, 297,
298, 301-305, 306-308, 311; passage
into South Atlantic by bottle-drift, 62,
63, 74, 80

Ink-berry. See Scsevola plumieri.

Insular factor in distribution, 334, 343,
358

Ipomcea acetosaefolia, 217

carnosa, 87, 92, 217, 384, 404, 421

kentrocaulos, 161

pes-caprae ; general treatment, 219 ;

seeds in beach-drift, 5, 6, 12, 17, 219,
242, 446 ; dispersal by currents, 87, 92,
219, 291 ; distribution of the species,
87, 217, 218, 219; on the Turks
Islands, 278-283, 288, and the Florida
sand-keys, 451, 452, 454; compared
with Convolvulus soldanella as regards
range, 220

tuba, 87, 92, 220, 280, 281, 291,

292, 452

tuberosa ; general treatment, 161 ;

popular name, 210; seeds in West
Indian beach-drift, 11, 12, 162, and in
European beach-drift, 24-27, 32-34,
161-163, being used as charms in the
Hebrides, 24

Ireland :

Stranded West Indian seeds, 26, 30,
122

Stranded bottles; one from the
vicinity of the Cape Verde Islands,
59, 72, 76; one from the channel
between the south-eastern Bahamas
and Hispaniola, 65, 72, 466, 477;
one from the Caribbean Sea to the
south of Jamaica, 59, 76; three
from the seas between Cuba,
Florida, and the Bahamas, 52;
seven from the vicinity of Cape
Hatteras, 49, 52; one from a posi-
tion to the south-east of Cape Cod,
50 ; ten from the seas south of Nova
Scotia and NeAvfoundland, 52; two

518

GENERAL INDEX

Ireland : Stranded bottles (continued) —
from Davis Strait, 484, 496 ; twenty-
three from mid-Atlantic to the
north-west of the Azores, 52, 53;
range of the sources of Irish bottle-
drift from the New World, 55, 79
A bottle reaching the Bahamas from
the vicinity of the Irish coast, 57,
66, 69, 72, 79, 464, 465, 477
Irminger, C. ; currents, drift-wood, and
drift-seeds in the North Atlantic, 20,
35, 40, 41, 43, 45
Isatis tinctoria (Woad), early cultivation

in the Azores, 397
Islands. See Insular factor.
Islets, Coral-reef; plant -stocking in the
West Indies and Pacific Ocean com-
pared, 453, 454
Isnardia palustris, 104, 105
Isoetes in the Azores, 380-382, 387, 420,
429

Iva imbricata, 451, 453

Jackson, Capt., on the Guinea Current,
476

Jacquin, Von, Rhizophora mangle, 96;

Hippomane mancineUa, 114; Mucuna

pruriens, 459
Jacquinia armillaris, 86, 109
Jamaica :

Rhizophora mangle, 98-101

Black River district; infiltration of
sea-water into the Great Morass, 101 ;
underflow of sea-water up the
estuary, 102; springs of the Great
Morass (Blue Hole), 104; vegetation
of the river, riverside, and Great
Morass, 104-106; Great Lake at
Pondside, 107; Salt Lakes district
and the vegetation, 107-109, 206

Savanna-la-mar district ; vegetation,
106; Cabarita River, 106; Bowen's
River, 107

Vegetation, bordering the beaches, 244 ;
of the woods, 16, 111, 118, 144, 155,
160, 226, 243; of rivers, ponds,
mangrove-swamps, 15-17, 104-109;
of the Blue Hole spring, 104 ; of the
Roaring River Falls, 16, 147, 211

Migrating birds on the highlands, 500

Beach-drift, 3, 6-9, 11, 12, 129;
seed -drift brought by the Main
Equatorial Current, 8, 129

Bottle-drift; brought by the North
Equatorial Current, 56, 57; by the
Main Equatorial Current, 61; and
from the vicinity of Ascension, 474,
475

Japan; Sphagnum, 334, 343, 349; Carex,
349

Johnson, J. Y. ; the Juniper in Madeira,
410, 431 ; plants of the Peak of Tene-
riffe, 411

Johnson, T., Arceuthobium, 427

Jones, F. Wood, 82, 312 ; bottle-drift as
illustrating plant -dispersal in the Indian
Ocean, 50, 302, 303, 305, 308 ; snakes
and crocodiles drifted to Keeling Atoll,
303, 486; floating corals, 165

J. M., Sapindus saponaria in Ber-
muda, 157

Jonston, J., 43; early allusion to the
drift fruits of Sacoglottis amazonica,
137

Jouan, H. ; on Tahitian and Marquesan

plants, 171, 247
Jourdan, S., early reference to Bermudian

plants, 204
Juan Fernandez, Uncinia, 498
Juglandese; fruit in Azorean beach-drift,

37, 38

Juglans; fruit in West Indian beach-
drift, 12, 13; distribution of the genus,
326

Juncus, 382; capacities for dispersal by
birds and winds, 418, 419, 422, 424

acutus, in Azores, 384, 388, 404,

421, 422

Juniper, Bro -berried ; J. oxycedrus,
430

zone in the Macaronesian islands and

on the Great Atlas, See under J.
oxycedrus.

Juniperus bermudiana, 204; J. brevi-
folia (see J. oxycedrus) ; J. com-
munis, 401, 430; J. macropoda, 426 ;
J. nana, 401, 430

oxycedrus (Cedro, Cedar) ; Azorean

variety, brevifoHa, 430 :

Affinities of the Azorean tree, 401,
430-432

Dwarfing, 373, 374, 382, 383, 387;
large size in the original forests, 392,
396; trees buried in volcanic ashes,
363, 393-395 ; use of the wood, 393,
397

Juniper-zone; on Pico, 369, 370, 371,
373-375, 386, 430; on Teneriffe,
Madeira, and the Great Atlas, 408-
410, 415, 416

Jumpers of the Lake District of Pico,
379, 387; of San Miguel, 382; of
Terceira, 383

Source in the Great Atlas, 405, 406;
dispersal by birds, 417, 418 ; the host
of Arceuthobium, 370, 375, 379, 386,
426; fruiting, 373, 430
Jussisea, 105

Jutland coast, stranded West Indian
seeds, 37

Kamel, Father, mentioned by Petiver, 163
Keane, A., the lake of the Grand Etang,
455

Kearney, T. H., the salt in sea-beaches
and halophily, 186

GENERAL INDEX

519

Keating, P., buried Juniper trees in
Flores, 395

Keeling AtoU; plants, 170, 240, 247, 248,
448; beach-drift, 132, 142, 143; vege-
table drift, snakes, and crocodiles from
Malaya, 302, 303, 486; bottle-drift
indications, 50, 303-305; stranded log
carrying seeds, 453; floating corals,
105; frigate-birds and boobies and
seed -dispersal, 32

Islands. See above.

Island, North, 453

Keller man, K. F., on denitrifying bac-
teria, 502

Kerguelen; bottle-drift and its indica-
tions, 295-300, 310; a habitat of
Uncinia, 498-501

Kermadec Islands, 220

Kerner, 96, 419

Kidder, Dr., seed dispersal in the Southern

Ocean, 500
Kilkee (Ireland), stranded West Indian

seeds, 31
Kleinia neriifolia, 408
Knowles, Miss M. C, stranded West

Indian seeds on the Irish coast, 31,

123

Knowlton, F. H., Cretaceous and Ter-
tiary plants of North America, 328

Knuth, R., Lysimachia, 432; AnagaUis,
480, 481

Kohl, J. G., on the vegetable drift trans-
ported in the Gulf Stream to Green-
land, Faroe Islands, and Europe, 20,
35, 40, 41, 43, 81

Krakatau, its re-stocking with plants,
116, 142, 190, 192, 200, 207, 253,
458

Krause, K., on Scaevola, 227-232, 235,

236, 447, 448
Kiikenthal, G., on Carex, 334r-358; on

Uncinia, 498-501

" L'Aigle," \ French sloops in the West
" L'Emeraud," / Indies in 1753 ; 264, 489
Labrador Current and chmate, 272
Laccadives, compared with the Bahamas,

255, 256, 274
Ladrones, 201

"Lady Montague" (American ship),
bottle-drift, 76, 482

Lagenaria vulgaris, gourds on Scandi-
navian beaches, 36, 146

Lagoas, in Pico. See Lakes of Pico.

Laguncularia, 309

racemosa; general treatment,

221; distribution, 86, 221; com-
parison of the West Indian and
Ecuadorian plants, 222; vivipary, 4,
221, 222 ; fruits in river-drift, 222, and
in beach-drift, 4, 12, 17, 222, 446;
plant as a constituent of the mangrove-
formation, 4, 10, 15, 100, 106, 108, 109,

202, 203, 283, 289, 454; dispersal by
currents, 4, 18, 86, 90, 222, 291, 462;
Florida sand -keys, 182, 451, 452
Lakes of Pico; Caiado, Das Teixas, Do
Ilheo, Negra, Paul, Rosada, 379-381,
437

Lamium purpureum, 391

Lansing, O. E,, on the vegetation of the
Florida sand-keys, 9, 115, 139, 156, 173,
183, 186, 190, 198, 203, 219, 231, 240,
250, 450

Lantana involucrata, 285, 288, 292

La Palma, Canary Islands, 497

Lapland, stranded seed of Entada
scandens, 36

Lathyrus maritimus, 186, 187

Laughton, J. K., 43; West Indian and
Mexican seeds and logs of mahogany
on the shores of Greenland and Ice-
land, 35, 40 ; Main Equatorial Current,
70, 443; Counter Equatorial Current,
476; Sargasso Sea, 461; waters of
Amazon estuary, 75

Laurel-woods of Macaronesian Islands,
365, 368, 369, 386, 393, 401, 406-410,
412-416. See Laurus, L. canariensis,
Persea indica, Oreodaphne foetens,
Phoebe barbusana.

Laurestinus. See Viburnum tinus.

Laurus, 417

canariensis (Persea azorica); in

Macaronesia, 401, 413; Pico, 369, 370,
374, 375, 380, 386, 387, 392, 393,
432; San Miguel, 382, 432; TenerifEe,
406, 408; Madeira, 407, 410; size of
existing trees in the Azores, 392, 395;
used for fuel, 398

indica. See Persea indica.

Leathery Turtle, caught off Scilly, 41

Lecythidacese, 211, 214

Lefroy, J. H., on Bermudian plants, 139,
197, 245

Leguminosae; behaviour of genera hold-
ing littoral species, 133; Andrews
on the development of the family,
318

Le Maout and Decaisne, Mucuna pruriens,
458

Librocedrus, 318, 327

Lilford, Lord; on the food of Canarian

wood-pigeons, 418
Limnanthemum humboldtianum, 223
Lindman, C, on Scandinavian beach-drift

from the West Indies, 21, 27, 36, 42,

43, 122, 123, 146, 153, 162
Ling. See Calluna vulgaris.
Liimaeus, 22, 37, 173, 448
Linschoten, J. H. van; on the forest-trees

of the Azores in the sixteenth century,

393, 397, 437, 440
Liquidambar, 318
Liriodendron, 318
Lithophila, 85

520

GENERAL INDEX

Littoral floras, West Indian and West
African compared, 83-95, 86; tropics
of the Old and New World compared
309, 453, 454
Littoral plants :

(a) Genera holding both littoral and
inland species; Anona, 175; Bar-
ringtonia, 175; Calophyllum, 156,
175; Canavalia, 133; Chryso-
balanus, 196; Clerodendron, 175;
CJoccoloba, 197; Colubrina, 200;
Cordia, 175; Erythrina, 208;
Guettarda, 175; Guilandina, 133,
456; Hibiscus, 214; Luffa, 223;
Morinda, 175, 226; Portulaca,
478; Scsevola, 175, 230; Sophora,
133, 237-239; Terminalia, 116,
175, 231; Tournefortia, 248. For
a discussion of the subject, see
chapters xiv, xv, xvi, of my book
on Plant -Dispersal, a list of genera
being given on p. 134.
(6) The relation between a littoral
station, buoyancy of seeds and
fruits, and dispersal by currents,
139, 140, 169, 216, 223, 229, 238,
239, 456, 457

(c) The relation between a littoral

station and xerophily, 169, 175,
216, 229, 239, 288, 293. Set
pp. 32, 39, 201, 515, of Plant-
Dispersal.

(d) The extension of inland plants to
the coast, 229, 288, 293, 448 {see
p. 131 of Plant-Dispersal); and
the extension of littoral plants
inland, 219, 227, 237-239, 288,
293. See under Littoral plants
in index of Plant-Dispersal for
further data.

(e) Littoral plants as parents of inland

species, 226, 456, 478. See Plant-
Dispersal, pp. 133-170.

(/) Littoral plants of the same genus
dividing the tropical world between
them, 227, 228; Carapa, 141, 228;
Rhizophora, 141, 228; Scsevola,
227, 247 ; Tournefortia, 228, 247

{g) Littoral plants where both frugi-
vorous birds and marine currents
disperse the species; Cassytha,
192; Scsevola, 230, 232; Ximenia,
252

(h) Littoral plants of the Azores, 384,
404; Jamaica, 106, 244; Teneriffe,
448; Turks Islands, 290, 291;
West Indies, 86, 87
LittoreUa lacustris in the Azores, 371,

378, 380, 381, 387, 403, 417, 420, 429,

432

Lloyd- Jones, A., Entada scandens seed

in Swansea Bay, 30
Locust-tree. See Hymenaea courbaril.

Logs, drifting; transporting seeds, 248,

291, 418, 421
Lomba, an eminence on the upper slope

of Pico, 360
Loranths, See Arceuthobium and Phora-

dendron.

Lord Howe Island, possessing New

Zealand Car ices, 348
Loro (Louro), Laurus canariensis, 432
Losningsteen, Norse name of Entada

scandens, 23
Lottin, seed of Entada scandens found

near the North Cape, 36
Lotus, 390 ; L. angustissimus, 492
Louisiana; stranded bottle-drift, 58;

shore plants, 191, 218
Lowe, R. T. ; Madeiran flora, 185, 406,

407, 410, 411, 435-437, 440; the

Salvages, 449
Lowenorn, Von; drift-wood in high

northern latitudes, 35, 40, 45
Lucuma, 29; L. mammosa, 29
Luffa, 223

Lumnitzera, 309, 454

Luzula, means of dispersal, 419, 427

purpureo-splendens, 371, 377, 387,

402

Lycoperdon (Puff-ball), falling rate of

spores, 424
Lycopodium; falling rate of spores, 424;

L. selago, 371, 374, 377, 379; L. com-

planatum, 375, 380; L. plumosum,

492

Lyngbye, H. C, West Indian seeds and
drift-wood in the Faroe Islands, 35, 40,
43, 122

Lysimachia nemorum, var. azorica, 371,
374, 377, 379, 387, 402, 419, 422, 432

Macaronesian Islands (Azores, Canaries,
Madeira); floras compared, 365, 385,
396, 398-416; plants of the woods,
406, 407, 415; zones of vegetation,
407-411, 415, 416; summit vegetation,
411, 416; history of their plant-stock-
ing, 411-414, 416; American elements,
412; comparison of climate and con-
ditions, 365, 409 ; the dispersing agency
and subsequent differentiation of the
pigeons, 418; the Campanulas, 428;
Juniperus oxycedrus, 431, 432

Machado, C, Portuguese botanist, 359,
364, 385

McKeehan, L. A., falling rates of spores,
423

Madagascar; bottle and seed-drift and
their tracks, 301, 304, 305; Sphag-
num and Carex, 334, 343-346

Madeira :

Bottle-drift; recovered on the island,
52, 53, 54, 484, 485; dropped into
the sea in the vicinity, 56, 67, 67,
464, 465

GENERAL INDEX

521

Madeira (continued) —

Flora compared with those of the
Azores and the Canaries (Teneriffe),
365, 385, 398^16, 406-411. See
under Macaronesian Islands for the
details of the comparison.
West Indian seed-drift, 38
Magdalena River, 17
Mahogany logs, transported by currents
to Greenland, Iceland, and North -
West Europe, 35, 40, 42, 48, 78

canoe made of ; stranded on the

Faroe Islands, 40
Maiden, J. H.. on the overlapping of the
ranges of Ipomoea pes-caprae and Con-
volvulus soldanella in eastern Australia,
220

Maize, half-eaten cobs in beach-drift of

South Devon, 29
Malagasy province, Sphagnum and Carex,

334, 343-346
Maldives, compared with the Bahamas,

255, 256, 274
Malva; M. mauritiana, 492; M. nicseen-

sis, 492
Mamillaria, 224, 287

Mammea, 84, 144, 326; M. americana,

4, 11-13, 87, 91, 144
Manchineel. See Hippomane mancinella.
Mangifera indica (Mango); "stones" in

beach-drift, 11, 30, 164
Mangle grande and Mangle chico (Rhizo-

phora mangle), 99
Mangosteen (Garcinia mangostana), in

European beach-drift, 28, 36
Mangroves :

Dispersal by currents, 86, 90, 94, 96,
451, 452

Mangrove-formation; West Indies, 4,
18; Turks Islands, 10, 289; Jamaica,
15, 106, 108-110; Florida sand-keys,
450; West Indian and West African
compared, 86, 89, 90; Asiatic and
and American compared, 309, 454

Mangrove fruits and seedlings in beach-
drift, 4, 10, 12, 15, 17, 18, 446, 451,
452

Stocking of islets with mangroves, 451
Vivipary of mangroves, 4, 502
(Further details will be found under

Avicennia, Rhizophora, and Lagun-

cularia)

Manicaria saccifera, 3-8, 11-14, 17, 25,

26, 31, 75, 86, 90, 127
Marm, H., Hawaiian flora, 170
Marantaceae, 315
Marianne Islands, 201
Marias Islands, 201

Martin, M., on the West Indian seed-drift
of the Hebrides and Mull, 22-25, 31,
41, 43

Martins, Ch. ; effects of sea-water immer-
sion on seeds, 188, 447 ; a pod of Cassia

fistula washed up in the south of

France, 154
Martius, on Manicaria saccifera, 128
Martyr, Cassia fistula in the West Indies,

155

Mary's Bean or Virgin Mary's Nut, names

of stranded West Indian seeds in the

Hebrides, 24
Mascarene Islands, Sphagnum and Carex,

334, 343-346
Masson, F., Azorean plants, 361, 385, 440,

493

Masters, on buried Juniper trunks from

the Azores, 395
Matricaria maritima, 187
Mauritius, Carex and Sphagnum, 344—346
Mayor, F. S., earliest cultivated plants

in the Azores, 397, 440
Medanos, moving sand-dunes in Peru,

270, 271, 493-495, 503, 504
Medicago, 390

Mediterranean, bottle-drift from the

Atlantic, 53, 56
Melocactus communis (Turk's-head Cac-
tus), 202, 224, 280, 283, 287, 292
Mentha; M. pulegium, 492; M. rotundi-

folia, 492
Menzies, Conocarpus erectus, 201
Menziesia, distribution, 419
polifolia (St. Dabeoc's Heath), 370-

373, 377, 386, 387, 402, 411, 433;

means of dispersal, 417, 419, 422
Mertensia maritima, 187
Mesembryanthemum ; a doubtful species

in the Azores, 384, 404 ; M. crystallinum

and M. nodiflorum in the Canaries and

Salvages, 448, 449
Mes quite (Prosopis juliflora), 168
Mexico, Gulf of; bottle-drift and its

indications, 57, 58, 61, 67, 71-73, 79,

444, 445

Miers, J., on Crescentia cucurbitina, 149;
on Grias cauliflora, 211

Milium lendigerum, 491

Millspaugh, C. F. ; author's indebtedness,
9 ; Cakile, 184-189 ; Conocarpus erectus,
201, 203; Ipomoea carnosa, 217-219;
Alacran Shoals, 187, 188, 201, 231,
240, 250; Cayman Islands, 138, 192,
197, 201, 206, 221, 225, 240, 250, 251,
456; Florida sand-keys, 115, 156, 182,
183, 203, 204, 231, 232, 450-453;
Turks Islands, 278-287, 291; Porto
Rico, 99, 168, 192; Jamaica and Cuba,
168, 251 ; Bahamas, 114, 210, 220, 225;
Yucatan, 157, 227

Milner, Sir W., West Indian drift seeds
in the crops of petrels at St. Kilda,
31, 32

Mimosa scandens, 32, 35

Missel- thrush, as a disperser of Juniper

seeds, 437
Mississippi delta, vegetation, 218, 252

522

GENERAL INDEX

Molesworth, Lord; marginal notes in
Martin's book on the Hebrides, 43

Molucca Beans, old name in Scotland
and the islands for West Indian drift
seeds, 22-25, 31-33, 42, 163, 458

Monaco, Prince of, investigations with
floats in the North Atlantic, 43, 47,
49, 51, 52, 53-56, 64, 68, 79-81, 461,
466, 469, 472, 483, 484

Monarde, N., old Spanish botanist, 45

Montevideo, bottle-drift, 71

Montrichardia arborescens, 455

Morelet, A., on the Azorean flora, 363,
365, 368-370, 374, 385, 440

Morinda, 175, 226; M. royoc, 87, 88, 93,
95, 225

Morocco, stranded bottle-drift, 51, 52, 53

Moronobea coccinea, synonym in part for
Symphonia globulif era, q. v.

Morris, Sir D. ; Jamaican beach seed-
drift, 7, 11, 12, 75, 112, 118, 128, 152,
190, 458; Sacoglottis amazonica, 28,
43, 133-137 ; dispersal of Uncinia, 337,
500 ; Orinoco and Amazon drift, 7, 75

Moseley, Miss M., a seed of Entada
scandens near Boulogne, 28

■ Prof. ; seed-drift off the coast of

New Guinea, 132, 155, 190; Fernando
Noronha, 170, 191, 220; dispersal in
the Southern Ocean, 500

Mouchoir Shoal, 255, 258, 264

Mountains, ascending air-currents, 355,
425, 439

Mucuna ; problems of the distribution of
the genus, 133; unidentified species in
the Trinidad beach-drift, 13, 121, 124

altissima, 120-123, 455, 459

pruriens, 122, 457-459

urens ; general discussion, 120 ;

station, 16, 87, 91, 123; seeds in West
Indian beach-drift, 11-14, 17, 121,
131 ; seeds in European beach-drift, 4,
22, 25-28, 26, 31-36, 122, 123, 131;
seeds in Azorean beach-drift, 37, 38;
dispersal by currents, 87, 123 ; species
confused with M. pruriens, 122, 457-
459

near M. urens, 87, 120; seeds in

West Indian beach-drift, 11-13, 121,
131 ; seeds in European beach-drift,
26-28, 34, 122, 123, 131, and in
Azorean beach-drift, 37, 38

Mueller, Baron F. von; on Acacia farne-
siana, 166, 172; on Juniperus com-
munis, 431

Miiller, K., currents and plant -dispersal
in the southern hemisphere, 39, 43

Mull, stranded West Indian seeds, 24, 31

Murray, Sir J., quoted by Wallace, 422

Musacese, 315

Mushrooms, falling rates of spores and
dispersal by winds, 355, 423, 424, 439
Mutisiaceae, 327

Myrica faya; in Azores, 369, 375, 376,
382, 386, 392-395, 398, 401, 433, 435;
in Canaries, 406, 408; in Madeira, 406,
407, 410; means of dispersal, 417, 418;
long established in Portugal, 361, 433,
434 ; origin of the name, Faya, 433

Myrsinaceae, 314, 315

Myrsme africana, 369, 370, 374-376, 380,
382, 383, 386, 392, 401, 406, 413,
434

Myrtacese, Andrews on the development

of the order, 317
Myrtus communis, 392

Nash, G. v., plants in the Inaguas and

in the Turks Islands, 286, 287
Natal, bottle-drift from off the coast to

Brazil, 62, 63
Natural Order. See Family.
Nautical Magazine, bottle-drift data, 46,

50, 54, 57, 66, 69, 443, 464, 474, 482-

484, etc.
Navidad Shoal, 255, 258, 264
Neill, P., Molucca beans, 43
Nepenthacese, 315
Nerium oleander, 491, 492
Nertera, 294

Neumayer, G., bottle-drift in high

southern latitudes, 49, 81
" Newcastle," H.M.S., bottle-drift in

North Atlantic, 50
Newfoundland, bottles thrown overboard

south of this region, 52, 53, 55, 66, 68
" New York," s.s., bottle-drift, 49, 465
New Zealand; Sphagnum and Car ex,

332-358, 347-352, 357 ; Uncinia, 498-

501 ; bottle-drift and current-coimec-

tions, 294^312, 299, 309-312
Nicaragua, bottle-drift, 50, 57-59, 61,

475

Nicker (Nickar), West Indian name of
Guilandina seeds, 30, 34, 140, 457

Niger ; probability of its seed-drift reach-
ing not only Brazil and the West Indies
but also Europe, 74, 81 ; flora, 99, 131,
159, 194, 196, 207

Niihau (Hawaiian Islands), Ipomoea
carnosa, 218

Nipa fruticans, 128, 168

Norfolk Island, possessing New Zealand
Carices, 348; current-cormections, 297,
298

North Cape (Norway) ; West Indian seeds
stranded on and doubling the cape, 36,
78, 81 ; stranded bottle-drift, 54, 55, 65,
495

Norway; stranded West Indian seeds,
21-23, 27, 35, 36, 78, 81, 173; stranded
bottle-drift, 52, 53, 65, 495; Cakile in
beach-drift, 186, 188; casks from the
Gulf of Guinea, 76, 81, 481 ; mahogany
baulks from the West Indies, 40

Notelaea excelsa. See Picconia excelsa.

GENERAL INDEX

523

Nova Scotia, bottles thrown overboard

south of this locality, 52, 06
Nymphaea ampla; in Jamaica, 16, 105,

107 ; in Grenada, 465

Ocean-holes, in the Bahamas, 258, 276,
503

Ochrosia, 5, 454

O'Connell, S., West Indian seeds on Irish
coast, 31

O'Dowd, Miss, seeds of Guilandina bondu-
cella on the shores of South Australia,
140

Olafsen, drift-wood in high northern lati-
tudes, 45
Oleander, 491, 492

" Olive " tree (Bucida buceras), 16, 17

Oliver, D., 134, 150, 251

Omphalea; O. diandra, 11-13, 159, 227;

O. triandra, 160, 226
Oolitic structure, in the seolian sandstone

of the Bahamas, 260-262, 502-504
Opuntias, 168, 204, 224, 278-280, 282, 287
Orchids; falling rate of seeds and their

dispersal by winds, 354, 355, 422-425,

439. See Habenaria and Serapias.
Oreodaphne foetens, 408
Orinoco seed -drift and its distribution

over the West Indian region, 6, 7, 8,

13, 19, 74, 75, 81, 129, 141, 486
Orkney Islands; stranded West Indian

seeds, 22, 25, 26, 32, 122, 162, 163,

458; stranded bottle-drift, 52, 53, 471;

stranded turtle, 40
Ormesteen (Adder -stone), old Norse name

of the drift seed of Guilandina bondu-

cella, 23
Ornithopus perpusillus, 492
Orton, Dr., pelagic organisms on English

Osborn, j! F., map of Grand Turk, 268,
491

Osmunda regalis, in Azores, 369, 376,
380, 434

Ostboe, Sargasso weed in the vicinity of

the Azores, 485
Ostenfeld, West Indian seeds on the

Faroe Islands, 35, 44
Owen, Captain; survey of the Turks

Islands, 489, 490
Oxalidacese, 315

Oxalis corniculata, in the Azores, 390,
391

Pacific Ocean :

Beach-drift of the tropical Pacific and
of the West Indies compared, 5

Bottle-drift, seed-drift, and the cur-
rents; number of bottles, 47; con-
nection round the Horn with the
South Atlantic, 63, 74, 300; across
the South Pacific from New Zealand
and Antarctic Islands, 295, 299, 300,

Pacific Ocean [continued) —

306-310; across the tropical Pacific
from equatorial America, 297, 298,
306, 310

Vegetation of coral-reef islets in the
West Indies and in the Pacific
Ocean compared, 453, 454
Page, J. ; bottle-drift observations of the

U.S.A. Hydrographic Office, 81, 312;

a remarkable drift from off Cape Horn

to Queensland, 295, 296 ; an interesting

drift in the tropical Pacific, 297
Paki, Jamaican name of Crescentia cucur-

bitina, q. v.
Palma (Canaries), Juniperus oxycedrus,

408

Panama Isthmus ; plants, 132, 191 ;

beach-drift, 6, 14, 17 ; derelict stranded

from Cape Hatteras, 72
Pancratium, 194, 447
Pandanacese, 315; Pandanus, 5, 454
Pantropical genera, 319
Pao branco, Azorean name of Picconia

excelsa, q. v.
Paritium, synonym in part for Hibiscus.

See under H. elatus, H. tiliaceus.
Parlatore, Prof., on Juniperus brevifolia,

431

Parrots, in connection with the dispersal

of Anona seeds, 175
Parry, Captain, bottle-drift in high

northern latitudes, 484, 496
Passiflora; fruits in beach-drift in South

Devon, 30, 289; P. pectinata, 289;

P. cuprea, 289 ; modes of dispersal, 289
Pauw, De, on drift-wood in high northern

latitudes, 45
Pavonia corymbosa, 105
Pax, F., Hippocratea, 13; Hippomane

mancineUa, 113-115; Hymensea, 140;

Omphalea, 160, 227; Lysimachia ne-

morum, 432 ; Anagallis filiformis, 480,

481

Pea -nut. See Arachis hypogoea.

Peel, C. v., on West Indian seeds and
turtles thrown up on the Outer Heb-
rides, 32, 40, 44, 122

Peirce, G. J., dispersal of Arceuthobium,
427

Pelagic organisms of warm latitudes on

English beaches, 29
Permant, T. ; West Indian seeds and other

drift stranded on the Hebrides, 22, 24,

32, 40, 41, 44, 161, 163
Penzig, 0., the new Krakatau flora, 116,

142, 154, 190
Peplis portula, in the Azores, 371, 378,

380, 387, 403, 417, 420
Persea, 318

azorica. See Laurus canariensis.

indica (Laurus indica), 369, 386,

401, 406-408, 435; dispersed by

pigeons, 418

524

GENERAL INDEX

Peru; medanos or moving sand-dunes,
270, 271, 493

Peruvian (Humboldt) Current, its in-
fluence on climate, 271, 272, 275

Peterson, P., respecting Foula in the
Shetlands, 34

Petherick, on drift-wood in high northern
latitudes, 45

Petiver, J. ; West Indian seeds on Euro-
pean beaches, 41, 44 ; Ipomoea tuberosa,
33, 161, 163 ; Manicaria eaccifera, 128 ;
Sacoglottis amazonica, 137

Petrels; West Indian drift seeds in their
crops, 31, 32; as seed-dispersers in the
Southern Ocean, 500

Philodendron, 16

PhcBbe, 412 ; P. barbusana, 408

Phoenix canariensis, 408

Phoradendron, 194

Phragmites, 179, 252, 377

Phyllanthus, 168 ; P. epiphyllanthus, 280,
281, 283, 285, 288, 292; P. falcatus, 85,
210

Physalia (Portuguese man-of-war), in
beach-drift; south of England, 29;
Azores and Canaries, 38

Physalis peruviana, 491

Phytelephas macrocarpa (Vegetable
Ivory), 17

Piazza, Captain; bottle-drift on east

coast of Africa, 303
Picconia excelsa (Notelsea excelsa), 369,

376, 386, 392, 401, 407, 408, 410, 418,

435

Pico (island and mountain of). See

under Azores.
da Vara, San Miguel, 382, 383, 430-

432

Topo, corrected altitude of, 365, 379

Pigeons, as seed-dispersers. See under
Birds.

Pigs, agents in dispersing seeds, 112, 144,
175, 243

Pines, in the Macaronesian islands, 408-
410

Pinus canariensis, 408, 409

" Pique," H.M.S., bottle-drift from Ascen-
sion, 482

Piscidia erythrina, 208, 209

Pistias, 3, 16, 104, 105, 107

Pithecolobium ; represented in Turks
Islands, 287, 292; P. filicifolium. 111

Plantago ; mode of dispersal, 418, 421 ;
PL coronopus, 384, 404, 421; PI.
lanceolata, 390 ; PI major, 390

Plate River (La Plata), estuary of, con-
cerning the distribution of its seed-
drift, 62, 73, 74, 81

Plocama pendula, 408, 448

Pluchea, 285, 292

Plukenet, on Manicaria saccifera, 31, 128,
129

Podocarpus, 294, 327

Polycarpon tetraphyUum, 491

Polygala vulgaris, on Pico, 370, 371, 372,

374, 377, 379, 386, 387, 402, 417, 435
Polygonum; dispersal by birds, 418, 421 ;

P. glabrum, 105-107; P. maritimum,

219, 384, 388, 404, 421
Polymorphous species, 313, 314, 322
Polytrichum, growths of, in the Azores,

371, 377, 379, 382, 383, 387; faUing

rate of spores and their dispersal by

winds, 424
Pontederia (Water Hyacinth), 3, 16, 105,

107

Pontoppidan, E., on the West Indian
seeds of Scandinavian beaches, 21, 35,
41, 44

Populus (Poplar), Portuguese names, 434
Porto Pym (Azores), beach plants, 218,
219, 384

Rico, stranded bottle-drift, 56, 58,

62

Portsmouth (England), West Indian seed
stranded, 28

Portugal; stranded bottle-drift, 52, 53,
68; bottles cast into the sea off the
coast, 57, 66

Portuguese Current, 54, 56

Portulaca ; P. halimoides, 109 ; P. oieracea
277, 279-281, 291, 477, 478; peculiar
species in islands, 478

Potamogeton ; fruits in floating river and
pond -drift, 16, 420; dispersal by water-
fowl, 417, 420; P. fluitans, 107; P.
natans, 378 ; P. plantagineus, 104, 105,
107; P. polygonifolius, 371, 378, 380-
382, 387, 403, 420

PotentiUa tormentilla, 371, 377, 379, 387,
402, 417, 419

Pouchet, F. A., currents in the southern
hemisphere, 39, 44

Povelsen, on drift-wood in high northern
latitudes, 45

Praeger, R. Lloyd ; West Indian seeds on
the Irish coasts, 31; falling rates of
seeds in connection with dispersal by
winds, 354, 422-425, 439; seed-
buoyancy, 447, 473

Prain, Sir D., on the wood of buried
Juniper trees in the Azores, 395

Premna, type of buoyancy in " stones "
of drupaceous fruits, 234

Prickles in beach-drift, 164

Prickly Pear. See Opuntia.

Prickly- Yellow (Zanthoxylum), prickles
in beach-drift, 164

Primocarex, 345, 357, 501

Primulacese, 314, 315

" Prince Eugene," s.s., bottle-drift from
off the Amazon to Florida, 75, 445

Prioria copaifera, fruits in beach-drift,
6, 17

Problem plants. See Acacia farnesiana.
Campanula vidalii, Chrysobalanus icaco.

GENERAL INDEX

525

Colubrina asiatica, Crudya spicata,
Grias cauliflora, Hibiscus tiliaceus,
Hippomane mancinella, Myrsine afri-
cana, Symphonia globulifera, Thespesia
popubiea

Prosopis, 102, 168

Proteaceae, 317, 327

Prunus lusitanica, 392, 400

Psamma arenaria, 186

Pteris aquilina (Bracken), 371, 375-377,
379, 387, 492

Pufi-ball (Lycoperdon), 424

Pumice, in the interior of San Miguel,
382, 383, 479; in beach-drift, 6, 164,
242, 248, 446, 479; as seed-carriers
across seas, 248, 291.

Purdy, J., in " Columbian Navigator,"
81; bottle-drift, 64, 465; boa-con-
strictor transported across the sea, 486

Pusey, J. H. ; Turk's-head Cactus, 224 ;
Grand Turk, 285 ; bottle-drift in Turks
Islands, 462.

Quercus, 326

Race, Cape; bottle-drift. See under

Newfoundland.
Randia aculeata, 287
Ravenala, 326

Rein, Dr., on the Calabash-tree in Ber-
muda, 146
Reinecke, F., Samoan flora, 171, 246
Remy, Niihau, Hawaii, 218
Rendle, Dr. :
Conocarpus erectus and its alleged
occurrence in the Pacific islands, 201
Foreign seeds in European beach-drift ;
Ipomoea tuberosa, 162; Lucuma,
species, 29
On Jamaican plants, 178, 184, 185,

193, 194, 197, 198, 200, 253
The use of the name, Mucuna pru-
riens, 459

Rennell, J. ; currents of the North
Atlantic, 20, 82; bottle-drift of high
northern latitudes, 46, 50, 57, 66, 484,
496; drift of a bottle from Ascension
to Guernsey, 482 ; Sargasso weed, 485 ;
drift-wood, 45

Reseda luteola, 491

Retama(Spartocytisus nubigenus),409,41 1

Rhachicallis rupestris, 85, 279, 291 (Rh.
maritima is a synonym)

Rhanmus, 406, 408, 417, 418 ; Rh. glandu-
losa, 410; Rh. latifoUus, 369, 375,386,
400, 407, 436; Rh. lycioides, 434

Rhinoceros, seed of Entada scandens
found in its caecum, 120

Rhizophora; distribution, 141, 228, 309;
period required for the growth of seed-
lings on the tree, 96, 109; Rh. conju-
gata, 96; Rh. mucronata, 96, 99, 100,
141 J Rh. racemosa, 99

Rhizophora mangle :

Distribution, 86, 141, 228, 308; dis-
persal by currents, 4, 86, 90, 291;
seedlings in beach-drift, 4, 12, 17,
446

Period required for the growth of the
seedling on the tree, 96 ; on its ability
to withstand drying, 96; on the
proportion of germinating fruits with
more than one seedling, 98; the
absence of dimorphism in the West
Indies, 99, 110; the length attained
by the seedlings on the tree, 99 ; the
influence of varying degrees of salinity
on the station, 99; colonies in the
midst of the Black River Morass, 102.
In Jamaica, 15, 106, 108-110; Turks
Islands, 10, 283, 289; Ecuador, 178;
Florida sand-keys, 451-454

Ribiera Grande blufls, Pico, 366, 496

Rice, Prof., Bermudian seolian rocks, 259

Ricinus communis, 290, 447

Ridley, H. N., plants of Fernando No-
ronha, 121, 170, 191, 220; Cassytha
filiformis in the Malay Peninsula, 192

Rio de la Plata. See Plate River.

• Negro, 131

Rivers ; as sources of seed-drift, 2, 3, 18,
etc. ; germination of floating fruits and
seeds in river-drift, 3, 5, 15, 16, 18,
125, 127, 205, 213, 243; temperature
of head-springs, 104. See Black River
under Jamaica, Guayas River under
Ecuador, Amazon, Orinoco, etc., and
Estuaries.

Robert, E., on the stranding of seeds of
Entada scandens near the North Cape
and in the White Sea, 36, 44; drift-
wood in high northern latitudes, 45

Rodriguez Island, Sphagnum plants, 344,
346

Romano, or Romani, Azorean name of
Vaccinium cylindraceum, 437

Ross, Captain; bottle-drift in Davis
Strait, 484, 496

Rubus species in Azores, 369, 376, 400.

Ruderal plants. See Weeds.

Rumex, 390

Russell, H. C. ; bottle-drift in Australian
waters, 295, 299, 312

Sabal; S. umbraculifera in Jamaica, 16,
105, 106, 109; S. palmetto of South
Florida, 179 ; S. blackburniana of Ber-
muda, 204

Sabine, Sir E., on the drifting of casks
from the Gulf of Guinea to the north
of Norway, 76, 81, 481, 482

Lady, 497

Sable Island and Cape Sable. See under

Nova Scotia.
Sacoglottis amazonica, 3-7, 11-14, 17,

25-28, 31, 86-88, 90, 91, 93, 95, 133,

526

GENERAL INDEX

For its representation in European
beach-drift, see pages 26, 133-137.
Safflower, 492

SafEord, W. E., on the genus Anona, 174-
181

Sagina procumbens, the possibility of its

dispersal by winds, 422, 424, 439
Sagittaria; S. lancifolia of Jamaica, 16,

104-107, and of South Florida, 179
Sagot, M. P., on Mucuna pruriens, 459
St. Croix, 6 ; shore plants, 244, 456, 457
St. Dabeoc's Heath. See Menziesia
polifolia.

St. Helena ; position with reference to the
equatorial currents and the indications
of bottle-drift, 60, 443, 474, 475, 531;
the flora and the currents, 459, 460 ; en-
demic species of Carex and Sphagnum,
343

St. KHda, 31, 32

St. Michael's, Azores (San Miguel), 382,

387, 393, 396, 397
St. Paul, Southern Ocean, Uncinia, 498,

501

St. Paul's Rocks, Equatorial Atlantic,
bottle-drift from their vicinity, 50, 59,
61, 67, 70, 443, 444, 475

Salcombe, South Devon, stranded West
Indian seeds with other seed-drift and
pelagic organisms, 28, 29, 30

SaHcornia ; in Jamaica and Ecuador, 101,
106, 108, 109; S. ambigua in Turks
Islands, 283, 290-292, and in the
Florida sand-keys, 451-453; distribu-
tion and mode of dispersal of the genus,
452, 453, 478

Salinity of estuaries. See Estuaries.

SaUx, 179

Salsola kali; in the Azores, 219, 384, 388,
404, 421 ; fitness for dispersal by cur-
rents and birds, 421, 447

Salt Key Bank, L. Agassiz on the, 261

Lakes district. See under Jamaica.

Salt-rakers, in the Turks Islands, 277, 487

Salvages, Mesembryanthemum, 449

Samolus valerandi, Azores, 421

Sampaiao, J. A. N., Portuguese botanist
in the Azores, 359, 364, 385

Sand-dunes, 503. See under Medanos.

San Domingo. See Hispaniola.

Sand-keys ; Florida, vegetation and plant
stocking, 450-453, comparison of vege-
tation of sand-islets in West Indies and
tropical Pacific, 453

Sanguinho, Azorean name of Rhamnus
latifolius, 436

Sanicula azorica, 375, 418

San Jorge (Azores), 364, 397, 427-^9,
432-438 ; Juniper trees, 396

Miguel (Azores); flora, 382, 387;

original forests and their destruction,
393, 396, 397; buried Juniper trees,
393-395

Santa Barbara, Terceira; vegetation,
383, 387

Maria, West Indian name of Calo-

phyUum calaba, q. v.

Rosa River, Ecuador, 100

Sapindus saponaria, 11, 25, 26, 37, 87,

88, 91, 95, 156, 219
Sapium, 114

Sapotacea ; seeds stranded on the Devon-
shire coast, 29; represented in the
floras of Madeira, Cape Verde Islands,
and Hawaii, 410, 488, 489

Sargasso Sea, 38, 64, 461, 485

Weed; in the Gulf of Mexico

and the Florida Stream, 485; in the
beach-drift of the West Indies, 6, of the
Turks Islands, 446, of the Azores, 38,
485, of Cornwall and Shetlands, 486

Sarraceniacese, 314, 315

Sassafras, 318

Saussure, Necker de, 44; stranded West
Indian seeds and turtles in the Hebrides,
32, 40, 41

Savaima-la-mar, Jamaica, vegetation,
106

Sceevola, 171, 175, 192, 193, 207, 227,
447; Sc. koenigii, 227, 447, 454; Sc.
lobelia. 447, 448; Sc. plumieri, 5, 17,
86, 92, 227-236, 242, 277-283, 288,
291, 446, 447, 451^54

Scandinavia; West Indian seed-drift,
21, 23, 25, 27, 35, 78, 81, 122, 146,
153, 162, 173, 208; stranded bottle-
drift, 52, 53, 65, 495

Scharff, R. F., 331, 460, 497; similarity
in the structure of the Bermudas and
the Bahamas, 273; origin of the Ber-
mudian flora and fauna, 466; on the
North polar area as a dispersion-centre,
325

Schimper, A. F. W., 294; Indo-Malayan
strand plants, 141, 157, 167, 192, 229,
458 ; littoral plants of tropical America,
143, 156, 203, 204, 447 ; buoyancy of
seeds and fruits and dispersal by cur-
rents, 93, 116, 156, 203, 207, 225, 231,
234, 242, 248; foUage of Juniperus
nana, 431, 432

Schjoth, A., West Indian seed-drift on
European beaches, 20, 44

Schmidt, J. A., on plants of the Cape
Verde Islands, 155, 167, 170, 488

Schott, G., on bottle-drifts and their
indications in the Atlantic, Indian,
and Pacific Oceans; Atlantic, 46-82;
Southern, Indian, and Pacific Oceans,
294-312; data relating to particular
regions and locaHties and utilised in
the Notes of the Appendix as given
in the list on page 441, viz. on the
Equatorial Atlantic Currents, Azores,
Bermudas, Canaries, Madeira, Turks
Group, etc.; derelicts, 472, 473

GENERAL INDEX

527

Schulz, on Cakile, 185

" Schwan," s.s., bottle-drift, 475

Scilly Islands; sca-fans, 22; capture of

a Leathery Turtle, 41.
Scirpus, 417; S. constrictus, 455; S.

fluitans and S, multicaulis, 371, 378,

380, 381, 387, 403, 420; S. palustris,

381, 403, 420; S. plantagineus, 105,
455; S. savii, 378, 403

Scitamineae, 315
Soleria, 455

Scotland and the Hebrides; stranded

West Indian seeds, 22-27, 31, 122;

bottle-drift stranded, 49, 52, 53, 65,

68. See also Hebrides.
Sea-apple (Manicaria saccifera), 127
Sea-bean (Entada scandens), 21, 22
Sea-birds, as seed-dispersers. See Birds,

Gulls, Petrels, Frigate-birds, Boobies.
Sea-coconut (Manicaria saccifera), 127
Sea Finns, West Indian drift seeds, 25
Sea-nut, West Indian drift seeds, 22
Sea-side grape, Coccoloba uvifera, q. v.
Securinega buxifolia, 434
Seeds ; falling rates, 354, 355, 422-425,

439; mucosity, 419, 421, 427; hypo-

cotylar, 213, 214, 243
Seemann, B., Dioclea panamensis, 132;

Acacia farnesiana, 171; Thespesia

populnea, 246; Ximenia americana,

253

Selaginellse, 375

Selala, the seedless Rhizophora of Fiji,
99, 110

Semper vivum, in the Canaries, 408, and

Madeira, 410
Senecio, capacity for dispersal by winds,

425, 439
Sequoia, 318, 327
Serapias, 377

Sernander, R., West Indian seeds and
fruits on the Scandinavian coast, 21,
36, 37, 42, 44, 122, 146, 153, 173
dispersal of Juniperus communis, 430 ;

Sesuvium, 101, 279,280, 290; S. portula-
castrum, 278-281, 288, 291, 451^54,
477

Sete Cidades, Azores, 394, 396
Seubert, M. ; on the flora of the Azores,
359, 362, 363, 368-370, 385, 389, 392,
428-438, 440 ; zones of vegetation on
Pico, 368; reliability of the altitudes,
362, 363, 425
Seven-year apple. See Genipa clusii-
folia, 210

Seven-year vine, Ipomcea tuberosa, 210
Seward, A. C, on the Glossopteris flora,
328, 331

Shaler, Prof., submarine springs off

Florida coast, 497
Sherardia arvensis, 491
Shetland Islands; West Indian seeds

stranded, 22, 24, 27, 34, 122; also

turtles and drift-wood, 40-42 ; stranded
bottle-drift, 52, 53, 65

Shreve, Forrest, the forests of eastern
Jamaica, 156, 243

Sibbald, Sir R., West Indian seeds on the
beaches of Scotland and of the islands,
23, 31, 33, 44

Sibthorpia, 420 ; S. europea in the Azores,
371, 375, 383, 387, 402, 420 , 436; on
its fitness for dispersal, 419, 422

Sicyos angulatus, 294

Sideroxylon, in Hawaii, 489; S. mermu-
lana, in Madeira, 410

Sierra Leone; bottle-drift from the
vicinity of St. Paul's Rocks, 50, 59,
475, and from off the north coast of
Brazil, 59, 476

Silene maritima ; in Iceland, 187; in the
Azores, 384, 388, 404, 421; capacity
for dispersal by currents and sea-birds,
418, 421

SUver Bank, 255, 258, 264

" Sir Edward Hawke," King's Schooner,
265, 489

Skye, Isle of; bottle-drift, 68

Sloane, Sir H. ; West Indian seeds on the
Irish and Scottish coasts and on the
Hebrides and the Orkneys, 21-24, 30-
34, 41, 44, 122, 128, 136, 137. Re-
marks on some Jamaican plants,
Spondias lutea, 111, 113; Hippomane
mancinella, 115; Mammea americana,
144; Crescentia cujete, 147; Cassia
fistula, 152, 155; Sapindus saponaria,
157; Grias cauliflora, 211; Guilan-
dina, 457. References to the drift
fruits of Manicaria saccifera, 128, etc.,
Sacoglottis amazonica, 136, 137, and
Ipomcea tuberosa, 161-163, the prickles
of Zanthoxylum, 164, and the sea-fans
of the Scilly Islands, 22

Smilax; in the Azores, 369, 376, 380,
392, 401; in the Canaries, 401, 406,
408 ; modes of dispersal, 417, 418

Smith, Lea, stranded alligator in the
Turks Islands, 487

Snakes, transported by currents to islands.
Keeling Atoll, St. Vincent, Turks
Islands, 303, 486, 487

Snuff-boxes, seeds of Entada scandens
from European beaches thus used, 25,
33

Soap-berry. See Sapindus saponaria.
Solan Goose, Molucca beans found in its

nest, 31
Solanum pseudo-capsicum, 491
Solidago semper virens, 385, 404, 421
Solomon Islands, Dioclea reflexa, 132
Solvent-stone, signification of old Norse

name for the stranded seeds of Entada

scandens, 23
Sonchus oleraceus, capacity for dispersal

by winds, 424, 425, 439

528

GENERAL INDEX

Sophora, 133, 239 ; S. chrysophylla, 239 ;

S. tetraptera, 239, 294, 307, 308, 311;

S. tomentosa, 6, 12, 87, 92, 198, 207,

237, 244, 286, 288, 291
Spain; stranded bottle-drift, 53, 68;

bottles thrown overboard off the coasts,

57, 66

Spartium juneeum, 492
Spartocytisus nubigenus (Retama), 409,
411

Spergularia marina, 384, 388, 404, 418,
421

Sphagnum. See under Carex compared
with Sphagnum, as indexed under
Carex, 332-358. The principal species
there referred to are : cymbifolium,
349; fimbriatum, 337-339, 348, 349;
junghuhnianum, 350; medium, 337-
339, 348, 349; mexicanum, 337, 338;
papillosum, 349; pappeanum, 344,
346; plumulosum, 337, 338; pulchri-
coma, 337, 341, 344, 346; rufescens,
341; torreyanum, 337, 338; turgi-
dulum, 341.
Spirula, shells in beach-drift, 6, 38
Spondias lutea (Hog-Plum), 4, 11-14,

17, 87, 91, 111, 193
Spores, faUing rates of, 355, 422-425, 439
Springs; probable sea-water springs in
the Black River Morass, 101, 102;
fresh-water springs in the same morass,
104; submarine springs, 497; springs
on Pico, 496, 497
Spruce, R. ; Carapa guianensis, 141, 143 ;
Grias, 212; Manicaria saccifera, 128;
Omphalea diandra, 160; Phytelephas,
17

Spunk-box, origin of the Hebridean name

for Entada scandens, 25
Stachys arvensis, 391
Stapf, Dr., Sacoglottis amazonica, 134,

135

Statice; numerous Canarian species,

408, 448; S. bahamensis, 285, 286;

S. limonium, 384
SteriUty and cold currents. See Climate.
Sterpin, J., translator of the book of

Debes on the Faroe Islands, 23
Stewart Island, Uncinia, 498
Storks, migrating from Europe to South

Africa, 354
Strom, Norwegian naturalist of the

eighteenth century, on the tropical

seeds in Scandinavian beach-drift, 22,

35-37, 41, 44, 146, 153
Suseda, 290

Subsecunda, Sphagnum subsection, simi-
lar behaviour in Africa and Australia,
344, 353, 357

Sugar-cane, early cultivation in the Azores,
397

Suriana maritima; general treatment,
239; in the Turks Islands, 278-283,

288, 289, 291; in the Florida sand-
keys, 451, 452; influence of wind-pres-
sure on its growth, 446, 447; repre-
sented in beach seed-drift, 6, 241, 242;
distribution, 85, 87, 92

Swallows, migration from Great Britain
to South Africa, 354

Sweden ; stranding of West Indian seeds,
27, 36, and bottle-drift, 52

Swietenia mahogani, 242; its associates
in the open forests of Jamaica and
Cuba, 111, 112. See under Mahogany.

Symphonia, 83, 84; S. globuUfera (Hog-
gum); general treatment, 243; de-
tails, 3, 15, 16, 83, 86, 88, 90-92, 95,
159, 205

Syngonium, 16

Tabernsemontanus, 44, 45
Tamarind, 155

Tamujo (Tamucho), name in Azores of

Myrsine africana, 434
Tansley, A. G., Sphagnum tussocks, 377
Taxus baccata (Teixo), in the Azores,

369, 370, 380, 386, 387, 392, 393, 401,

405, 406, 417, 418, 436
Taylor, N., plants of Grand Turk, 286,

287

Teneriffe; flora and zones of vegetation
compared with those of Pico (Azores)
and Madeira, 406-411, 415; summit
plants, 411 ; shore plants, 448; Sphag-
num, 344, 346 ; ascending air-currents,
425; climate compared with that of
Pico and Madeira, 409; angle of the
mountain's slope, 366; Dragon-tree,
487; beach-drift, 38 ; bottle-drift from
Greenland waters, 484, 496

Terceira; Santa Barbara ascent, 383,
387; original forests, 393; buried
Junipers, 395

Termmalia, 83, 84, 116, 175, 204, 231;
T. katappa, 6, 11, 116

Tetragonia expansa, in Azores, 385

Texas, the chaparral scrub, 167-169,
229; bottle-drift stranded, 58. See
under Mexico, Gulf of, for other
data.

Thespesia, 83, 326; T. populnea, general
treatment, 244 ; compared with Acacia
farnesiana and Hibiscus tiliaceus, 172;
seeds and capsules in beach-drift, 5,
6, 12; references to station, etc., 87,
92, 116, 168, 194, 197, 200, 287, 288,
291 ; T. danis, 246

Thomson, A. L., migration of storks, 354

Thrinax, 109, 287

Thuret, G., floating capacities of seeds,
447

Thymus serpyUum, var. angustifoUus of
the Azores, 370-373, 376, 377, 383,
386, 387, 402, 407, 411; concerning
its dispersal, 417, 419, 422

GENERAL INDEX

529

Tierra del Fuego. See Fuegia and Cape
Horn.

" Tilbury," H.M.S., long drift of mast, 40
Tilia, 326

Tillandsia, tumble-weed in Peru, 271,
493

Tillinghast, W. H., on old maps of the
Bahamas, 264, 276

"Times"; capture of a Leathery Turtle
off Scilly, 41 ; bottle-drift in the
Southern Ocean, 49, 300

Tobago; beach-drift, 6, 13, 121, 129;
beach-trees, 245 ; stranded bottle-drift,
60, 61, 73, 75

Toland, J., marginal notes in a copy of
Martin's book on the Hebrides, 43

Tomlinson, seed of Entada scandens on
the Irish coast, 31

Tonning, West Indian seeds on Scandi-
navian coasts, 22, 23, 35, 37, 44, 146,
153, 208, 209

Tournefortia, 248; T. argentea, 247-
251, 453, 454 ; T. sarmentosa, 248

gnaphalodes; general treatment,

247-251; in the Turks Islands, 202,
278-283, 288, 291, 292 ; on the Florida
sand-keys, 451-454; distribution and
dispersal, 87, 88, 93, 95, 228; repre-
sented in beach-drift, 6, 242 ; influence
of wind-pressure on growth, 446,
447

Tree-Euphorbias. See Euphorbia sty-
giana.

Tree-Heaths. See Erica arborea and E.

azorica.
Tree-Lobelias, 321

Trelease, W., on the Azorean flora, 364,
385, 440; proportion of indigenous
plants, 389, 391 ; re-discovery of
Isoetes, 429; on Campanula vidalii,
427; on other plants, 185, 359, 362,
389, 392, 431, 433-438, 491, 492

Treub, M., the re-stocking of Krakatau
with plants, 116, 142, 154; experiments
at Buitenzorg on Scaevola kcenigii,
234, and Tournefortia argentea, 249

Trichomanes speciosum, in Azores, 375,
379

Trifolium, 390 ; T. arvense, 492

Trinidad Island (West Indies); beach-
drift, 6, 13, 121, 129, 130, 131, 136,
143 ; as a centre for receiving and dis-
tributing seed-drift, 74, 81 ; the home
of Manicaria saccifera, 129, and Saco-
glottis amazonica, 133-136; stranded
bottle-drift, 60, 61, 67, 70, 73, 74, 75,
80, 442-445, 474, 475

Tristan da Cunha; stranded seeds of
Dioclea reflexa, 132; the habitat of
Uncinia, 498-501

Tristram, H. B., on a north polar centre
of dispersion, 325

Tropseolace«, 314, 316
M M

Trovisco, Azorean name of Daphne

laureola, 428
Tschudi, J. J. von, on the medanos or

moving sand-hills of Peru, 270, 271,

494

TuUoch, J., West Indian seeds from the

Shetland coasts, 34, 131
Tumble-weed, in sandy plains of Peru,

271, 493

Tunis, stranding of bottle-drift from the

Atlantic, 53
Turk's-head cactus. See Melocactus com-
munis.
Turks Islands :

Bottle-drift; stranded on the islands,
49, 54^57, 58, 64, 462-465; bottles
dropped overboard in the vicinity
of the islands, 465, 477 ; connection
with Bermuda, 470
Iguanas, alligators, and snakes, 486
Stranded seed-drift ; suitability of the
islands for the study of oceanic seed-
drift in transit, 2, 8, 14, 19; list of
plants supplying the foreign seed-
drift, 10, 11; the materials of the
local seed-drift, 446
The flora; general description, 277-
293 ; the separate islands. Pear Cay,

278, Penniston Cay, 278, Long Cay,

279, Gibb Cay, 280, Eastern Cay, 280,
Round Cay, 281, Greater Sand Cay,
281, Cotton Cay, 282, Salt Cay, 283,
289, Grand Turk, 283-290 ; dispersal
agencies, 290; influence of wind-
pressure on plant-growth, 446.

The geology and general characters,
254-276. See summary of results on
p. 273.

Turtles, carried by the currents from West

Indian waters to north-west Europe,

40, 42, 48, 78
Typha ; in Jamaica, 15, 105-107;

capacity for dispersal by winds, 423

424, 439

Ubussu palm (Manicaria saccifera), 128
Ule, E., Sphagnum in South Brazil,
353

UmbeUiferse, unidentified shore plant of

Teneriffe, 448
Uncinia, 294, 358, 498-501; dispersal by

birds, 337, 500; U. compacta, 498;

U. brevicaulis, 498; U. jamaicensis,

500; U. kingii, 501; U. macrolepis,

498, 501

Underground waters, soakage seaward in

volcanic islands, 497
Uniola paniculata, 85, 280, 282, 291, 451,

453

United States Hydrographic Office, charts
of bottle-drift tracks in the North
Atlantic, 47, 54, 66, 75, 82, 466-471,
etc. See under J. Page.

530

GENERAL INDEX

Urban, I., references to West Indian
plants in his Symbolse Antillanae, 92,
128, 134, 144-148, 181, 184, 217, 220,
226, 244, 250, 426, 455-457

Utricularia, in Jamaica, 16, 104, 105, 107

Vaccinium; in the Canaries, 406, 408;
in Madeira, 407, 410; dispersal by
birds, 418; V. cylindraceum, in the
Azores, 369, 370, 374, 375, 380, 382,
383, 386, 392, 401, 437

Vaughan, T. W. ; on the formation of
the Western Bahamas, 254, 276, 504;
the seolian rocks of the Bahamas and
Bermudas compared, 273, 502 ; ocean-
holes, 258, 503. A bulky volume by
this author on reef-corals and their
associated phenomena is now (October
1916) being pubhshed by the Carnegie
Institution of Washington.

Vegetable-Ivory palm (Phytelephas), 17

VeleUae, washed up on the south coast of
England, 29

Venezuela; bottle-drift brought by the
Main Equatorial Current, 60, 61, 73, 75

Verbascum, in Azores, 375

Verbena officinaHs, 491

Vette NjTC (Fairy kidneys), old Norse
name for the stranded seeds of Entada
scandens, 23, 25

Vibe, A., West Indian seed-drift in Scan-
dmavia, 20, 36, 41, 44

Viburnum; in the Canaries, 405, 406,
408, 438; mode of dispersal, 418; V.
tinus, in the Azores, 360, 369, 375,
376, 382, 386, 392, 401, 405, 437

Vicia sativa, 492

Vidal, Captain; survey of the Azores,
365, 366; discoverer of Campanula
vidalii, 427

Vigna, 252 ; V. lutea, 250, 252 ; V. luteola,
6, 87, 92, 250

Vinca rosea, 290

Viola; palustris, 371, 377, 387, 402;

paradoxa, 411 ; teydensis, 411
Virgin Islands, shore plants, 116, 244,

457

Mary's Nut, Hebridean name of

stranded West Indian seeds, 24
Visnea, 412

Vogel, Dr., on the shore vegetation of
African west coast, 159, 194, 207

Wahlenberg, G., West Indian seeds
stranded in northern Scandinavia, 35,
36, 44

Wales, stranding of West Indian seeds
and fruits, 26, 30

Walker, W. F., on the Azores, 440; the
original forests and the trees buried in
volcanic ashes, 393-397, 437; " sar-
igasso " weed washed up on the islands,
485; the MadeVtan juniper, 410

Wallace, A. R., the Azorean flora from
the standpoint of dispersal, 390, 413,
440 ; dispersal of seeds by winds, 422,
439; plant-stocking of Bermuda, 466;
survival of ancient groups of plants, 318

Wallace, Rev. J.,\onWest Indian seeds,

Wallace, Dr. J., / etc., thrown up on
the Orkney Islands, 22, 23, 33, 40, 41,
44, 131, 161-163

Waltershausen, S. von, on West Indian
seeds and drift-timber stranded on
Iceland, 20, 35, 41, 45

Warde, Mrs. H. B., 238

Warming, E., 45; seeds blown across the
Cattegat, 425; foUage of Juniperus
nana and J. communis, 431, 432

Warnstorf, C, Sphagnaceae, 333-358,
411, 440 ; the connections of the Azorean
Sphagna, 478

Warren, Miss U. ; seeds of Entada scan-
dens on the north coast of Cornwall, 45

Water-hyacinth. See Pontederia.

Watkins, F. H., on the first salt-rakers
and the original condition of the Turks
Islands, 184, 276, 277, 487

Watson, H. C, on the Azorean flora, 359,
362, 385, 394, 440 ; the total number
of plants and the introduced element,
389-391 ; the vertical distribution of
Hochstetter and Seubert criticised,
362, 363, 425 ; summit plants of Pico,
370; aquatic plants, 378; character
and composition of the original forests,
391-393 ; beach plants of Porto Pym,
384 ; Campanula vidahi and the Maca-
ronesian Campanulas, 427, 428; dis-
covery of Isoetes azorica, 429, and
Littorella lacustris, 432; the Azorean
Juniper, 431 ; other references to plants
218, 364, 371, 434-436, 438, 492; the
snow on Pico, 372

Webb, P. B., on Dracaena draco in
Madeira, 487

Webster, J. W., on the Yew of Pico, 397,
437, 440

Weeds, their significance, 391, 493
Wells of Pico, 497

Welwitsch, on Acacia farnesiana in the
Cape Verde Islands, 170

West Austrahan Current; influence on
the cHmate, 272; its probable role in
seed dispersal, 301

Indies; West Indian and West

African strand-floras compared, 83-
95; West Indian seeds on European
beaches, 20-45; bottle-drift from the
West Indies to Europe, 52, and from
Europe to the West Indies, 57. See
the summary on p. 78 for a guide to
the general bottle-drift results for the
West Indies, also under Bahamas,
Caribbean Sea, Greater and Lesser
Antilles.

GENERAL INDEX

531

Westmoreland Morass (Jamaica), ve^yeta-
tion, 16, 106

West- Wind Drift Current and the indica-
tions of bottle-drift, 60, 295-300, 305-
312

White, Dr., on the source of the flora of
St. Helena, 460

Sea, West Indian seed-drift on its

shores, 36, 78
Whymper, ascending air-currents on the

Andes, 425
Wiegmann's Archiv fur Naturgeschichte

362, 368, 425
Wight, Isle of; stranding of a West

Indian seed, 28
Wilkes, Captain, bottle-drift in the

Southern Ocean, 49, 300
WiUdenow, on the West Indian home of

Acacia farnesiana, 167, 168
"William Torr," wrecked in Davis

Strait ; drift of casks, 50
Wilser, L., on the north polar centre of

dispersal, 325
Wind; dispersal of seeds and spores,
354, 422^25, 439; seeds of the maho-
gany tree carried by the wind, 243;
ascending air-currents on mountains
as seed and spore carriers, 425, 439;
effects of wind -pressure on shrubs in
the Turks Islands, 446.
" W. L. White," derelict schooner, drifted

across the North Atlantic, 472
Woad (Isatis tinctoria), early cultivation
m the Azores, 397

Woodwardia; W. radicans, 370, 375-
W. virginica, 378 '

Worm, 0., an old Danish naturalist; on
Scandinavian tropical seed-drift, 21,
35, 45 *

Wortley, E. J., on Hymensea courbaril
in Jamaica, 140

Xerophily and a littoral station, 228, 229,
238, 239. For further references see
Littoral plants (c); and for a discus-
sion of xerophily as a product of latec
geological ages, due to the progressive
differentiation of climate, see p. 319.

Ximenia, 83, 253 ; X. americana, 87, 92,

Yew, in the Azores, 397, 437. See Taxus
baccata.

Yucatan, bottle-drift stranded, 53, 466.

See Central America, Honduras,

Nicaragua.
— — - Strait, traversed by drift brought

by the equatorial currents, 58, 70-72
Yuccas, 168

Zanthoxylum, prickles in beach-drift,
164

Zaragoza mangrove (Conocarpus erectus),
201

Zeleny, J., on the falling rates of spores,
Zingiberaceae, 315

Zygophyllum, in the Canaries, 448, 449

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Library Bureau Cat, no. 1137