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UNIVERSITY OF NEBRASKA,

BoTANICAL SURVEY OF NEBRASKA.

Conducted by the Botanical Seminar.

Ai

Preliminary :

The Plan and Scope of the Survey.

LINCOLN, NEBRASKA,
1892.
Published by the Seminar.

Qt.
ITA
N36

A.3T15 13

BOTANICAL SURVEY OF NEBRASKA.

CONDUCTED BY THE

Botanical Seminar of the University.

ADVISORY COMMITTEE:

Hon. Caas. H. Morritu, President of the Board of Regents.
JAMES H. CANFIELD, Chancellor of the University.
CHARLES E. Bessry, Professor of Botany.

MEMBERS OF THE SURVEY:

Jarep G. Smiru, M.A. Roscoge Pounp, M.A. ALBERT F. Woops, M.A.
HerBerRT MarsLanD, B.Sc. Per A. Ryppere, B.Sc. FRED CLEMENTS.

BOTANICAL ADVISOR:

Cuanues I. Bessey, Px.D.

SECRETARY AND TREASURER:

ALBERT F. Woops.

HERBARIUM COMMITTEE:

AuBert F, Woops. Perr A. RyDBERG. FRED CLEMENTS.

EDITORIAL COMMITTEE:

Roscoe Pounb. AuBertr F. Woops. HerBERT MARSLAND.

PRELIMINARY: THE PLAN AND SCOPE OF THE SURVEY.

The object of this, the first publication of the Botanical Survey
of Nebraska, is introductory only. It is intended to serve asa
preface and introduction to the future publications of the Survey.

Although the general plan of the Survey was agreed upon in
June of this year, and no little collecting done in accordance with
it in July and August, the Survey was not formally organized till
August 24. At that time the organization set forth on the pre-
ceding page was effected. As there indicated, the Survey will be
entirely under the control of the Seminar. The Seminar selects
the members and assigns the work, and its members will bear
the entire expense of the Survey. But in the conduct of it they
will be advised and assisted by the gentlemen who have kindly
consented to act as the advisory committee, and in botanical and
scientific matters they will rely largely on the advice and assist-
ance of Dr. Bessey.

In entering upon the Survey, the Seminar is fully aware of the
difficulties which must necessarily beset such an undertaking
when conducted by private means and enterprise. But if there
are difficulties attending the conduct of the Survey by private en-
terprise, there are also undoubted advantages. The members
need never fear to do purely scientific work, they need not spend
their time in strengthening their official rather than their scien-
tific position, and they need not be distracted from more impor-
tant matters by the burden of continually demonstrating to doubt-
ing Thomases the practical nature of their undertaking.

No apology for the undertaking of such a survey is needed.
The changes which are taking place in the flora of the state have
already been noted by Mr. Webber in the preface to his cata-
logue. The rapid settlement of the western portions of the state
is undoubtedly accelerating these changes, and requires that those
regions be examined at once, while the native flora is intact. The

6

number of collectors and persons interested in botany in the state
is increasing, and they demand that the local flora—tor the de-
termination of which, as regards the Anthophytes, two manuals
are required in many parts of the state—be systematically set be-
fore them, and that the lower plants of the state be made access-
ible to them. At present, but a limited number can form any ac-
quaintance with the larger part of the plant life of the state. Mr.
Webber's catalogue and the supplements to it have been of very
great assistance to botanists and collectors in Nebraska. But
they are not enough, and, besides, are far from representing the
whole flora of the state, as is shown by the additions made almost
daily. To continue to add to Mr. Webber’s catalogue in a hap-
hazard way will needlessly and indefinitely postpone the complete
presentation of our flora which is desirable. Systematic botan-
ical exploration of the state will bring such a catalogue much
sooner, make it a far better one, and cannot fail to develop many
things of practical as well as scientific importance.

It would be greatly to the public, interest to have a state Nat-
ural History Survey. But the time when such a survey can be
conducted with puklic funds seems far distant. ‘The next best
thing is a private survey. This the Seminar has undertaken for
the botanical part, believing that the time when such a survey
should be had is at hand.

It is the intention of the Seminar to make a thorough and com-
plete survey of the state, extending over several years and cover-
ing all forms of plant life. Those parts of the state which are
less known will be carefully explored, and, as far as possible, com-
plete collections will be made there. Distinct cases have been
provided in the Herbarium of the University for the Survey Her-
barium, and several collections of fair size and no little impor-
tance have been made already. The plan is to make the Survey
Herbarium a complete representation of the flora of the state, to
indicate there, as far as possible, the distribution of each species,
to determine the floras of the various regions of the state, and to
provide for the botanists of the state a herbarium for the study

7

of the local flora as well_as complete and accurate lists and cata-
logues, and monographs of the more difficult groups. At the close
of the Survey the Herbarium will be presented to the University.
And during the progress of the Survey it will be accessible to
all persons, prepared to use it, who wish to study the plants
of Nebraska or any group of them.

In addition to the reports, catalogues of local floras and mono-
graphs of particular groups, principally of the lower plants, will
be published. Several such monographs are now in preparation,
and more are contemplated. These will make possible a more
thorough acquaintance with the plant life of the state by the pub-
lic generally, and, it is hoped, enable the public schools of the
state to do much which at present they cannot do for lack of the
numerous and expensive books which such work requires. But
the Seminar will aim to make the work of the Survey scientific
rather than popular.

While the Survey is essentially a private undertaking, con-
ducted by a private organization and carried on with private
means, the members of the Seminar recognize that their connec-
tion with the State University, most of them being graduate stu-
dents at that institution, pats them under obligation to the public.
They will endeavor, therefore, to give such practical direction to
the Survey as will be consistent with a purely scientific aim. The
grasses of the state, the trees and woody plants, injurious and
beneficial fungi and their observed effects, and other matters of
interest to Agriculturist and Horticulturist, will receive special
notice. But the bulletins of the Agricultural Experiment Sta-
tion are the place for the most of such work, especially the popu-
lar side of it. The Survey must often treat them on an equality
' with matters of little economic or purely scientific importance.

With no intention of being unduly radical, the Seminar will
endeavor to have the publications of the Survey fully represent
the most recent development of Botany in all directions. The
Survey is intended for scientific purposes, and its publications
for scientific eyes, primarily. Furthermore the Seminar cannot

s

assent to the doctrine that the public are too weak to stand a
draught of modern scientific results, unless strongly diluted with
ancient and untenable ideas, no longer held even by those who
continue to put them off upon others.

UNIVERSITY OF NEBRASKA.

BoraNICAL SURVEY OF NEBRASKA.

Conducted by the Botanical Seminar,

Il.
Report on Collections Made in 1892.

LINCOLN, NEBRASKA, U.S. A.
Published by the Seminar.

1893.
(Distributed April 15, 1893.)

CONTENTS.

1. Flora of the Sand Hill Region of Sheridan and Cherry
counties, and List of Plants Collected on a Journey through the
Sand Hills in July and August, 1892, by Jared G. Smith and
Roscoe Pound.

2. Notes on the Canon Flora of Sioux county, with List of
Plants Collected in July and August, 1892, by A. F. Woods.

3. Miscellaneous Additions to the Flora of the State and New
or Noteworthy Species from Various Localities.

NOTE.

In this report, in addition to full lists of the two principal col-
lections made during the past year, a list is given of all additions
to the reported flora of Nebraska up to January Ist, 1893, as far
as possible. A great deal of material remains to be examined,
and many things which should appear in this report must be de-
ferred for the reason that the publication has already been held
back much longer than was intended.

The thanks of the Seminar are due to the gentlemen who have
collected for the Survey in different parts of the state. Rev. J.
M. Bates, of Valentine, collected many of the species from north-
western Nebraska. Dr. H. Hapeman, of Minden, collected the
algee reported from that place. Mr. D. A. Saunders, of the Bo-
tanical Departmant of the University, collected many of the spe-
cies reported from Lancaster county, and determined most of the
alge. Messrs. W. H. Skinner and A. T. Bell, of the Crete High
School, collected the Hrysiphew reported.

The members of the Seminar wish to remind collectors that no
species can be reported unless a specimen is deposited in the .
herbarium of the Survey.

I

FLORA OF THE Sanp HILL ReGIon or SHERIDAN AND CHERRY COUNTIES AND
List or PLANTS COLLECTED ON A JOURNEY THROUGH THE SAND
HILLs In JuLy anp Auaust, 1892, By JARED G.
SmMitH AND Roscoe Pounp.

On July 6th we started from Alliance, and between the 6th and
Sth we traversed on foot the sand hill region of Sheridan and
Cherry counties, emerging at Johnstown in Brown county. From
Johnstown we went to O’Neill, following, at no great distance, the
Fremont, Elkhorn, & Missouri Valley railroad. We drove across
country from O’Neill to Lincoln, arriving there August 6th.

The greater part of the collecting was done in the sand hills
and in the lake region of Cherry county.

GENERAL FEATURES OF THE REGION TRAVERSED.

The main group of the sand hills of western Nebraska extends
from the 103d meridian, midway between the North Platte and
the Niobrara, eastward to the 98th meridian. It extends south-
ward to the 41st parallel, and has for its northern boundary the
Niobrara. In passing into the sand hills from the old lake basin
around Alliance there is a perceptible fall. One does not go up,
but goes down; and there is a general slope towards the east, in-
dicated by the fact that in the wet valleys the lake or pond is
generally at the eastern end. We met with no exception.

The sand hills are a region free from drainage. The surface
water, instead of flowing off in the river channels, collects in the
valleys and forms countless lakes or ponds without outlet. The
valleys are, as a rule, parallel, and have a general east and west
trend. They are not strictly continuous, being separated by low
ridges or groups of low hills. But the passage is always easy from
one to the next, while getting over the side of the valley is dif-
ficult and sometimes well nigh impossible.

a

6

Between these more or less pa-allel valleys are ranges of hills
of nearly pure sand, rising from one hundred to five or six hun-
dred feet above the center of the valley. In some cases the val-
leys are bounded on north and south by high, steep hills; oftener
the sides rise gradually through a succession of hills of increas-
ing size. The hills bear all manner of fantastic shapes, showing
their formation to be due to winds rather than to water. The
upper slopes are abrupt and the ridge is narrow, and a character-
istic mark is the great pits or craters blown out of their sides or
tops. These “blow-outs” are usually on the southwest face of a
hill, though there are many exceptions.

We came upon two streams. The North Loup rises in a marshy
region in west-central Cherry county around Brush Lake. Where
we first saw it, it was very cold and swift and about as deep as it
was wide (2 to 3 ft.) It flows. constantly and rapidly increasing
in size, through a valley bounded by high, steep sand hills.
Sometimes the valley is broad and level, but as a rule it is narrow,
and often a perfect gorge. The stream has a limestone bottom,
and not far from its source has innumerable falls—some of them
quite large. The Gordon is a clear stream, more sluggish than
the other, but swift compared with streams in the eastern part of
the state. It was quite wide and deep where we came upon it,
and flowed through a wide, swampy valley, bounded by high
sand hills.

In eastern Cherry county there is a region of permanent lakes,
of which the largest, Dad’s Lake, seemed to be about 5 to 6 miles
long and 1 to 1{ miles wide. Beyond this fine body of water
there is a network of lakes, of which Pelican Lake is the largest.
From a hill above this lake twenty-four are visible.

In Sheridan county and western Cherry county the valleys
were, roughly speaking, of two kinds—wet valleys and dry val-
leys. In some seasons valleys are dry that are wet at other times,
but some valleys appear to be permanently dry. They are usu-
ally quite long and the sides are provokingly steep and high.
The wet valleys vary in length from 2 or 3 to 15 miles and are

7

somewhat narrow. Some of them are beautiful as seen from a
hill-top, and some of the best are occupicd by ranches. Between
the valleys in the passes are often a large number of small ponds.

It is commonly said by stockmen and others interested in the
region that the sand hills were entirely bare of vegetation at a
comparatively recent date and have only commenced to be grassed
over since the days of the Indian and the buffalo. This is doubt-
ful. We have accounts of the sand hills written in the early part
of this century which give the salient features of the landscape
about as they appear to-day. Furthermore we have access to col-
lections of plants gathered in the sand hills from 1839 to 1858,
and these collections agree in species and type with those collected
in more recent years. There seems to be neither increase nor
diminution in the number of species. The region is one where
physical conditions may vary greatly in a term of years. We were
told by stockmen who had been in the hills a long time that the
lakes sometimes disappear during periods of drouth, and that one
year acrop of hay may be cut where, the year before, there was a
fine body of water. We saw one case in point. In one valley the
bottom for a long distance was white with the dried remains of a
species of Chara But two or three insignificant ponds remained,
and they were full of the living plant. If one sees the sand hill
region for the first time when bare of vegetation in winter or early
spring or after the drying out of July and August, he may easily
get the idea that they have never been grassed over. When the
freshening up comes after the rains, he may conclude that they
are becoming turfed over for the first time.

FLORA OF THE SAND HILL REGION.

There are, roughly speaking, three floras in the region. The
hills are sparsely covered with the typical sand hill species. The
dry valleys and the upper parts of the wet valleys (farthest from
the lake have a characteristic flora scarcely different from that of
the prairies of eastern Nebraska. It is evidently the prairie flora
of the surrounding regions mixed with a few individuals which

8

have crept down from the hills. The wet valleys, especially around
the lakes, have a flora of their own, and it isin this flora that
there is the most localization of species. The species peculiar to
the sand hills and blow-outs and the prairie species of the dry
valleys are common to the entire region, from the point where we
entered the sand hills east of Alliance to the sand hills near Ne-
ligh in Antelope county. We also found the same sand hill
species—no more and no less—on a sandy bluff near Loretto in
Boone county. The species peculiar to the wet valleys change as
one passes from west to east, only two or three being found
throughout the region. A species is frequently confined to
isolated patches or widely separated lake-basins.

The following species are to be found in every blow-out
throughout the region: Stipa comata, Oryzopsis cuspidata,
edfieldia flexuosa, Tradescantia virginica, EHriogonum anniuwm,
Oenothera serrulata, Prunus pumila, Lathyrus sp. (ornatus?),
Astragalus pictus var. filifoiius, Hymenopappus filifolius. Not
only are these species in every blow-out, but they are on every hill.
Besides these, the most common sand hill inhabitants are: _Andro-
pogon scoparius, A. hallii, Muhlenbergia pungens, Abronia Srag-
rans, Rosa virginiana var. arkansana, R. fendleri, Acerates viridi-
flora, Erigeron divergens, Haplopappus spinulosus, Chrysopsis
villosa, and Laciniaria squarrosa var. intermedia,

Few species are common to all the wet valleys or to all the wet
valleys of a particular locality. The most widely distributed are.
Sisyrinchium angustifolium, Salix longifolia, Glycyrrhiza lepidota
Amorpha fruticosa, Utricularia vulgaris, Lobelia spicata, and
Rudbeckia hirta.

The dry valley flora includes about the same species as the
prairie flora of Lancaster county. In addition there are Haplo-
pappus spinulosus and Cnricus undulatus. Prunus demissa was
found in a very peculiar dry valley in Sheridan county. It is
common on the banks of the North Loup and in wet valleys in
the lake region of eastern Cherry county.

THE PRAIRIE FLORA OF BOX BUTTE COUNTY.

The prairie in Box Butte county was covered with Agropyrun
glaucum and Stipa comata, the former, apparently, predominating
on lower or waste ground, the latter on high ground. Bulbilis
dactyloides was found in small patches, and Oryzopsis cuspidata,
a typical sand hill species, had wandered out along the trail seven
or eight miles from the hills.

The most striking flowers of the prairie were Tradescantia vir-
ginica, Erysimum asperum, Lupinus plattensis, Spiesia lamn-
berti, Astragalus adsurgens, and Thelesperma filifolium, all very
common. Pentstemon albidus, Astragalus mollissimus, and Evi-
geron pumilus were also common near Alliance. As one ap-
proaches the sand hills, these disappear. Monarda citriodora
becomes very common on the prairie, and Phlox douglasti and
Polygala alba on the hill-sides.

Several ofthe typical’sand hill plants had wandered out on
the prairie and were found within a few miles of the Sheridan
county line. Stipa comata Tradescantia virginica, Phlox doug-
last, and Plantago patagonica var. gruphalioides were common
to,the prairies of Box Butte county and the sand hills.

NOTES ON THE FLORA OF BROWN, ROCK, HOLT, AND ANTELOPE
COUNTIES.

We saw only the worst parts of Sheridan and Cherry counties.
But on leaving the lake region, we came at once upon the best
part of Brown county. We left the lake region of Cherry county
through a wet valley over thirty miles in length, in which, for the
last few miles, flows a branch of Plum creek. This valley had
most of the characteristics of the ordinary wet valley, but the soil
was better, and in the last third of the valley it was not so marshy,
and the hills at the sides were not so completelyjof pure sand.
The commonest plant in this valley was Froelichia floridana. Be-
sides a large number of wet valley species, we found as we pro-
gressed the ordinary prairie flora. Soon after entering Brown
county, we came quite suddenly upon a new region. One of the

10

first things that attracted our notice was a small clump of Popu-
lus monilifera on the banks of a small stream. We had not seen
a tree or woody plant larger than a dwarf willow since the day we
started.

The prairie in Brown county was yellow in every direction with
Rudbeckia columnaris and in some fields it had the appearance of
being cultivated. Other common plants were Oenothera serru-
lata, O. rhombipetala, O. albieaulis, and Laciniaria scartosa.

We did not see the best portion of Rock county. The part we
traversed resembled, on a smaller scale, the region at the head of
the North Loup. For the most part we were in wet valleys, full
of small ponds and swamps, and bounded by low sand hills with
occasional blow-outs. Lilia philadelphicum and Lobelia
spicata were common.

We entered Holt county southwest of Stuart, and passed through
low, wet prairies covered with a luxuriant growth of grass. The
whole region is devoted to hay-making, and seems excellently
adapted to it.

In the part of Antelope county we passed through we found
ourselves again in the sand hills. The well known sand hill
species—especially Andropogon hallii—were everywhere. In ad-
dition there were Calamovilfa longifolia and Cycloloma platyphyl-
lum in great abundance.

LIST OF PLANTS COLLECTED, AND NOTES.

(Species designated by a * not previously reported. )
Laciniaria squarrosa (Ti.) Hill var. tutermedia (Lindl.) DC.
Cherry county, July 23. (137) Sand hills throughout the
region.
Laciniavia seariosa (.) Hill,
Cherry county, July 27. Dry valleys, and prairie in Brown
county.
Laciniaria punctata (Hook.) OK.
Dry valleys, wet valley Cherry county, J uly 27,

11

Laciniaria pycnostachya (Michx.) OK.
Wet valley, Cherry county, July 27, also wet valleys, Rock
county, July 30.
Chrysopsis villosa (Pursh) Nutt.
Cherry county, July 27. Sand hills throughout the region.
Haplopappus spinulosus (Pursh) DC.
Sheridan county, July 11. (66) Sand hills throughout
the region.
Solidago speciosa Nutt. var. rigidiuscula Torr. & Gray.
Dry valleys in Sheridan and western Cherry counties.
-lsfer salicifolings Lam.
In canon, Long Pine, July 29. (153)
Erigeron divergens Torr. & Gray.
Cherry county, July 20. (250) Sand hills throughout the
region.
*EHrigeron ramosus (Walt.) BSP. var. beyrichti (Fisch. & Mey. )
Torr. & Gray.
In wet valley near Hannah's ranch, Cherry county, July 27.
(154)
HKrigeron pumilus Nutt.
Box Butte county, July 6. (155)
Antennaria plantaginifolia (L.) Hook.
Cherry county, July 14. (60) Prairies, Box Butte county,
and dry valleys throughout the region.
Rudbeckia augustifolia (DC.) Benth. & Hook.
Dry valleys, western Cherry county.
Rudbeckia columnaris Pursh.
Cherry county, July 14. (146) In wet valleys, central
Cherry county; prairies, Brown county.
Rudbeckia columnaris Pursh var. pulcherrima (DC.) Torr. &
Gray.
LaPorte’s ranch, Cherry county, July 23. (147)
Rudbeckia hirta L.
Sheridan county, July 13. (145) Wet valleys throughout
the region.

Helianthus aus L.

Waste places around a ranch, Cherry county, July 26.

Helianthus petiolaris Nutt.
Box Butte county, July 7. (61)
Helianthus rigidus (Cass.) Desf.

Cherry county, July 26. (71) Sand hills, and dry valleys

throughout the region.
Thelesperma gracile Gray.
Cherry county, July 18. (141) Sand hills, western and
central Cherry county.
Thelesperma filifolium Gray.
Prairies, Box Butte county, July 6. (142)
Hymenopappus filifolius Hook.
Box Butte county, July 7. (59) Sand hills throughout
the region.
Crepis runcinata (James) Torr. & Gray.
In wet valley, Sheridan county, July 9. (152)
Artemisia canadensis Michx.

Brown county, July 29. (65) (Lower leaves sparsely silky

canescent. Farther south than its usual range. S.)
Artemisia ludoviciana Nutt.

Cherry county, July 26. (62) Dry valleys throughout the
region.

*Senecio aureus L. var. borealis Torr. & Gray.

Sand hills, eastern Sheridan county, July 9. (61) (Agrees
with specimens in Herb. Engelm. collected by Hayden,
“Loup Fork, July 24,” 186-, and named by Dr. Gray.
This is much farther south than its usual range, and it is
probably one of the “buffalo disseminated plants.” See
Bot. Gaz. XVII, 321. 8.)

Cnicus undulatus (Nutt.) Gray.

Dry valley, Sheridan county, July 21, (63),

Cnicus undulatus (Nutt.) Gray var. canescens (Nutt. ) Gray.

Prairies, eastern edge of Box Butte county, July 7. (64)
Sand hills throughout the region.

13

Troximon cuspidatum Pursh.

Dry valleys, Sheridan county.
Lactuca ludoviciana (Nutt.) DC.

Wet valley, Cherry county, July 26. (68,70)
Lactuca pulchella (Nutt.) DC.

Cherry county, July 15. (69) Valleys throughout Cherry
county.

Lygodesmia juncea (Pursh) Don.

Cherry county, July 19. (86) Sand hills and blow-outs
throughout the region. (The length of the upper leaves
approaches L. rostrata L. juncea. Gr. But it is 3-5
flowered, corymbosely branched, flowers terminal on the
upper branches. I consider it an intermediate form be-
tween juncea and rostrata. 8S.)

Symphoricarpos occidentalis (R.Br.) Hook.

Cherry county, July 23. (54) Valleys here and there

throughout the region.
Galium trifidum L.
In thicket of Prunus demissa, falls of the North Loup,
Cherry county, July 22. (193)
Specularia perfoliata (L.) A.DC.
Box Butte county, July 7. (211)
Campanula aparinoides Pursh.

Along the North Loup and in wet valleys in the lake region,

Cherry county, July 26. (186)
Lobelia spicata Lam.

Cherry county, July 19. (37) Wet valleys throughout the
region.

Acerates viridiflora (Raf.) Ell.

Cherry county, July 15. (134) Sand hills throughout
the region.

Acerates viridiflora (Raf.) Ell. var. linearis Gr.

Cherry county, July 23. (1348) Sand hills, Cherry
county.

14

Asclepias verticillata L.
Dry valley, Cherry county, July 23. (135)
Asclepias stenophylla Gray.
Sand hills, Sheridan county, July 12, Cherry county, July
23. (136)
Asclepias arenaria Torr.
Cherry countv, July 20. (133) Sand hills, western and
central Cherry county.
Asclepias speciosa Torr.
Cherry county, July 19. (132) Sand hills and dry valleys,
Sheridan county, and western Cherry county.
Asclepias incarnata L.
Wet valleys at head of North Loup and in’ lake region,
Cherry county, July 20, 26. (181)
Apocynum cannabinum L.
Cherry county, July 19. (140) Dry valleys, Sheridan
county and western Cherry county.
Plantago eriopoda Torr.
In wet valley, Sheridan county, July 9. (177)
Plantago patagonica Jacq. var. gnaphalioides (Nutt.) Gray.
Prairies, Box Butte county, July 6. (76) Dry valleys
throughout the region. :
Verbena hastata L. :
Wet valley, Cherry county, July 23. (77)
Verbena stricta Vent.
Valleys here and there in Cherry county. (55)
"erbena bracteosa Michx.
Box Butte county, July 6; Cherry county, July 24. (157)
Wet valleys near the Gordon and in the lake region.
Lycopus sinuatus Ell.
Wet valleys near the Gordon and in the lake region, July 24.
(88)
Koellia virginiana (L.) OK.
Brown county, July 29. (160)

Hedeoma hispida Pursh.
Box Butte county, July 6. (75)
Monarda citriodora Cerv.
Prairie, Box Butte county, July 7. (57)
Stachys palustris L.
Cherry county, July 15. (56) Wet valleys, eastern Sheri-
dan county, and lake region of Cherry county.
Teucrium occidentale Gray.
Valley of Dad’s Lake, July 26.
Utricularia vulgaris L.
Cherry county, July 15. (72) In the Gordon, July 24;
wet valleys throughout the region.
Pentstemon gracilis Nutt.
Wet valleys, western Cherry county, July 14. (173)
Pentstemon albidus Nutt.
Prairies, Box Butte county, July 6. (174)
Pentstemon caeruleus Nutt.
Box Butte county, July 7. (175)
Pentstemon grandiflorus Nutt.
Prairie, Brown county, July 29.
Mimulus glabratus HBK. var. jamesii (Torr. & Gray) Gray.
Margin of cold spring in wet valley at Dye’s ranch, Cherry
county, July 19. (79)
Monnera rotundifolia Michx.
In dried-up pond, Cherry county, July 15. (81)
Veronica peregrina L.
Box Butte county, July 6. Wet valley at head of North
Loup, Cherry county, July 19. (158)
Gratiola virginiana L.
Wet valleys near the head of the North Loup, Cherry county,
July 20. (176)
Physalis mollis Nutt. var. cinerascens Gray.
Dry valley, Sheridan county, July 12. (78) (Apparently
the same as specimens in Herb. Univ. collected by Mr.

16

Rydberg in Scott’s Bluff county. The typical mollis is a
much smaller leaved plant of the Texas-Arizona region. 8.)
Physalis virginiana Mill.
Dry valleys, Sheridan county, July 12. (150)
Physalis lanceolata Michx.
Dry valleys, Sheridan county, July 12. (151)
Lappula redowskii (Hornem.) Greene.
Box Butte county, July 6. (169)
*Krynitzkia jamesii (Torr.) Gray.
Box Butte county, July 7. (170)
Krynitzkia fendleri Gray.
Dry valley, Sheridan county, July 9. (172)
Lithospermum angustifolium Michx.
Box Butte county, July 7. (171)
Lithospermum carolinense (Walt.) McM.
Sheridan county, July 11. (80)
Onosmodium carolinianum (Lam.) DC. var. molle (Michx.) Gray.
Dry valley, Sheridan county, July 9. (58)
Ellisia nyctelea L.
Box Butte county, July 7. (73) (Macrocalyx Trew, does
not seem available, as it- was not applied in a binomial
name. P.)
Phlox douglasii Hook.
Box Butte county, July 7. (74) Sand hills, Sheridan
county, and western Cherry county.
Gilia linearis (Nutt.) Gray.
Box Butte couaty, July 7. (159)
Ipomoea leptophylla Torr.
Brown county, July 29. (82)
Cuscuta arvensis Beyrich ?
On Polygonum sp., not in flower, J oy’s ranch, Sheridan
county, July 10. (205)
Steironema lanceolatum (Walt.), Gray.
Wet valleys, lake region of Cherry county, July 26. (165)

17

Comandra pallida A.DC.
Sand hills, Sheridan county, July 12, western Cherry county,
July 15. (255)
Lupinus plattensis Wats.
Box Butte county, July 7. (51)
Lotus americanus (Nutt.) Bisch.
Cherry county, July 19. (42) Wet valleys at head of
North Loup, and in lake region.
Psoralea campestris Nutt.
Dry valley, Sheridan county, July 9. (45)
Psoralea lanceolata Pursh. :
Sheridan county, July 9. (46) Sand hills and blow outs
throughout the region.
Psoralea incana Nutt.
Box Butte county, July 7. (47)
Psoralea esculenta Pursh.
Dry valleys Sheridan county, July 12. (44)
Amorpha canescens Nutt.
Sheridan county, July 18. (43) Dry valleys throughout
, the region.
Amorpha fruticosa L.
Banks of the North Loup; wet valleys throughout the
region.
Kuhniastera purpurea (Vent.) MacM.
Brown county, July 28. (38) Dry valleys throughout the
region.
Kuhniastera candida (Willd.) OK.
With the preceding. (39)
Kuhniastera villosa (Nutt.) OK.
Sand hills and dry valleys throughout the region.
Astragalus mollissimus Torr.
Box Butte county, July 6. (48)
Astragalus caryocarpus Ker.
Dry valley, Sheridan county, July 13. (50)

Astragalus microlobus Gray.

Box Butte county, July 7. (53)
Astragalus adsurgens Pall.

Box Butte county, July 6. (156)
Spiesia lamberti (Pursh) OK.

Box Butte county, July 6. (41)

Glycyrrhiza lepidota Nutt. ;

Cherry county, July 26. (52) Wet valleys throughout the
region.

Lathyrus sp. (ornatus Nutt?)

Sand hills and blow-outs throughout the region, very com-

mon. In fruit only. (49)
Prunus demissa Walpers.

Dry valley, Sheridan county, July 12; Banks of North Loup,
Cherry county, July 21, Brown county, July 29. Wet
valleys in the lake region. (91)

Geum strictum Ait.
Falls of the North Loup, Cherry county, July 21. (90)
Potentilla arguta Pursh.

Cherry county, July 22. (94) Wet valleys at head of
North Loup and along the Gordon.

* Potentilla pennsylvanica L. var. strigosa Pursh.
Dry valleys, Sheridan county, July 12. (85)
Potentilla norvegica L.

Wet valley, Cherry county, July 21. (86)
Agrimonia eupatoria L.

In canon, Long Pine, July 29. (84)
Rosa fendleri Crepin.

Sheridan county, July 9. (88) Sand hills, Sheridan county,
and western and central Cherry county.

Rosa virginiana Mill. var. arkansana (Porter) Best.

Dry valleys, Sheridan county, July 12, Cherry county, Jul
23. (87) Sand hills throughout Cherry county.

Amelanchier alnifolia Nutt.
In canon, Long Pine, J uly 29.

19

Ammannia coccinea Rottb.
Cherry county, July 26. (89) A peculiar form, found once
in a wet valley in the lake region.

Lythrum alatum L.

Valley of Dad’s Lake, Cherry county, July 26. (162)
Oenothera albicaulis Nutt.

Brown county, July 28. (212)
Oenothera coronopifolia Torr. & Gray.

Box Butte county, July 6. (213)
Oenothera rhombipetala Nutt.

Sheridan county, July 12. (214) Dry valleys and sand
hills throughout the region; prairies, Brown county.

Oenothera serrulata Nutt. .

Sheridan county, July 12. (215) Prairies, Box Butte
county, July 7, Brown county, July 28. Blow-outs and
sand hills throughout the region. In the sand hills it has
a different aspect—low, very woody, spreading, much
branched, flowers dark yellow. On the prairie it is erect,
simple, slightly woody at base only, flowers light yellow.

Gaura coccinea Nutt.
Box Butte county, July 6. (210)
Mamillaria vivipara (Nutt.) Haw.

Cherry county, July 15. (216) Prairies, Box Butte county,

and sand hills and dry valleys throughout the region.
Opuntia rafinesquit Engelm.

Cherry county, July 15. (217) Sand hills throughout the
region.

Opuntia fragilis (Nutt.) Haw.

Joy’s ranch, Sheridan county, July 10. (218) Sand hills,
Sheridan county.

*Cornus pubescens Nutt.

Long Pine, July 29. (183) (Has both appressed and silky
hairs on the same leaves, as in C. baileyi Coulter & Evans,
but the stone is that of C. pubescens. It may possibly be
a hybrid between C. pubescens and C. stolonifera Michxs. )

20

Cicuta virosa L. var. maculata (L.) Coulter & Rose.
Wet valley, LaPorte’s ranch, Cherry county, July 22.
(196)
Euphorbia petaloidea Kngelm.
Sheridan county, July 11. (96) Blow-outs, Sheridan
county, and Western Cherry county.
Euphorbia hexagona Nutt.
Sand hills, Antelope county, August 2, (203)
Croton texensis Muell.
Sand hills, Sheridan county, July 9. (95)
Polygala verticillata L.
Cherry county, July 21. (93) Dry valleys throughout the
region.
Polygala alba Nutt.
Sandy hillsides, eastern Box Butte county, July 7. (184)
Polygala sanguinea L.
Wet valley, Rock county, July 30. (185)
Rhus radicans L.
Banks of the North Loup, July 23. Wet valleys through-
out the region.
Linum sulcatum Riddell.
Prairies, Box Butte county, July 7. (283) Sand hills and
blow-outs, Sheridan county, and western Cherry county.
Oxalis stricta L.
Pullman, Cherry county, July 20. (167)
Malveopsis coccinea (Nutt.) OK.
Box Butte county, July 6. (166)
Cleome serrulata Pursh.
Rock county, July 28. (163) Waste places around ranches
(only) in eastern Cherry county,
Cristatella jamesti Torr. & Gray.
Side of canon, in sandy soil, Brown county, J uly 29. (164)
Lesquerella argentea (Pursh) MacM.
Box Butte county, July 7, (194)

21

Erysimum asperum DC,
Box Butte county, July 7. (195)
Argemone platyceras Link & Otto.
Prairies, Box Butte county, July 7. (161) Sand hills
throughout the region.
Nymphaea advena Solander.
In lake, Hannah’s ranch, Cherry county (lake region), July
27, (168)
Anemone cylindrica Gray.
Dry valley, Cherry county, July 15. (180)
Ranunculus aquatilis L. var. trichophyllus Chaix.
Ponds in wet valleys at the head of the North Loup, July
19, in the North Loup, July 20, in the Gordon, July 24.
(181)
Ranunculus cymbalaria Pursh.

Wet valley, Wilson’s ranch, Sheridan county, July 11.
(182)

Delphinium azureum Michx.
Cherry county, July 23. (179) Dry valleys throughout
the region.
Paronychia jamesi Torr. & Gray.
Sandy hillsides, Box Butte county, July 7. (189)
Silene antirrhina L.
Dry valleys, Cherry county, July 20. (188)
Cerastium nutans Raf.
Prairies, Box Butte county, July 7, wet valleys at the head
of the North Loup, Cherry county, July 20. (187)
Arenaria laterifloru L.
In canon, Long Pine, July 29. (192)
Lychnis drummondiu Wats.
Dry valley, Sheridan county, July 12. (190)
Allionia angustifolia (Nutt.) OK.
Box Butte county, July 6. (148)
Allionia hirsuta Pursh.
Dry valley, Sheridan county, July 12, valley of Pelican Lake,
Cherry county, July 26. (143)

22

Abronia fragrans Nutt.

Sand hills, Sheridan county, July 7-9. (147)
Froelichia floridana (Nutt.) Moq.

Wet valley, Cherry county, July 27. (198)
Cycloloma platyphyllum (Michx.) Mogq.

Dry valley, Cherry county, July 19. (99) Sand hills and

waste places around Neligh, Antelope county, August 2.
Chenopodium leptophyllum Nutt.
Dry valley, Sheridan county, July 9. (97)
Eriogonum annuum Nutt. :

Sheridan county, July 11. (199) Sand hills and blow-outs

throughout the region.
Polygonum emersum (Michx.) Britton.

Cherry county, July 19. (200) Wet valleys throughout

Cherry county.
Polygonum amphibiwm L.
In lake, Hannah’s ranch, lake region of Cherry county,
July 26. (200)
Polygonum hartiwrightti Gray.
Wet valleys, lake region, July 26. (201)
Rumex venosus Pursh.
Box Butte county, July 7, Sheridan county, July 9. (197)
Sand hills throughout Sheridan county.
Rumex persicarioides L.
Antelope county, August 2. (204)
Salix longifolia Muhl.

Sheridan county, July 11. (208) Small pools in passes
between the valleys and in the sand hills throughout the
region.

Salix cordatu Muhl. var. vestita Anders.

Cherry county, July 22, (209) Wet valleys at the head

of the North Loup and in the lake region.
Salix tristis Ait.

Wet valleys, Cherry county and Brown county, July 27.

(280)

23

Habenaria leucophaea (Nutt.) Gray.

Cherry county, July 19. (219) Wet valleys at the head

of the North Loup and in the lake region.
Sisyrinchium angustifolium Mill.

Joy’s ranch, Sheridan county, July 10. (223) Wet val-

leys throughout the region.
Yucca glauca Fraser.

Sheridan county, July 11. (222) Sand hills, Sheridan

county, and western Cherry county.
* Allium reticulatum Fraser.

Sandy hillsides, Box Butte county, July 7; sand hills, west-

ern Sheridan county. (225)
Lalium philadelphicum L.
Wet valleys at the head of the North Loup, July 20; wet
valley, Rock county near Newport, July 30. ( 220)

Juncus bufonius L.

Wet valley, Oxyoke ranch, Sheridan county, July 17. (191)
Juncus marginatus Rostk.

Around lake, Hannah’s ranch, July 27. (237)
Juncus nodosus L.

Valley of Pelican Lake, Cherry county, July 26. (239)
Juncus nodosus L. var. megacephalus Torr.

Valley of Pelican Lake, July 26. (240) Grew near the lake
ina different part of the valley from the preceding, and
in much greater abundance.

* Juncus longistylis Torr. & Gray.

Wet valleys, Sheridan county, July 9. (241)
Juncus balticus Deth.

With the preceding. (242)
Commelina virginica L.

Sides of sand hills around wet valley, Oxyoke ranch, Cherry
county (just beyond Sheridan county line), July 14.
(222)

Tradescantia virginica L.
Prairies, Box Butte county, July 6, (221) Sand hills and

24.

blow-outs throughout the region; one of the commonest
blow-out inhabitants,
Panicum virgatum L.
Dry valley, Cherry county, July 21. (106)
Panicum dichotomum L.
Sheridan county, July 12. (123)
Spartina gracilis Trin.
Wet valley, Sheridan county, July 9. (117)
Spartina cynosuroides (L.) Willd.
Wet valleys at head of North Loup, Cherry county, July 19.
(130)
Andropogon scoparius Michx.
Sand hills throughout the region.
Andropogon hallit Hack.
Antelope county, August 2. (206) Sand hills from eastern
Cherry county eastward.
Alopecurus geniculatus L.
Box Butte county, July 12. (112)
Stipa comata Trin. & Rupr.

Prairies, Box Butte county, July 6. (125) ~ Sand hills

throughout the region.
Oryzopsis cuspidata (Nutt.) Benth.

Box Butte county, July 7. (114) Sand hills, especially
blow outs, Sheridan county and western Cherry county.
(Stipa membranacea Pursh; O. membranacea (Pursh)
Vasey. But as there was already a Stipa membranacea
L.—festuca uniglumis Sol.—Pursh’s name is hardly
available. P. )

Oryzopsis micrantha (Trin. & Rupr.) Thurber.

In canon, Long Pine, July 29. (101)
Muhlenbergia pungens Thurb.

Blow-outs and sand hills throughout the region.
Phleum pratense L.

In canon, Brown county, July 29. (124)
Sporobolus airoides (Steud.) Torr.

Joy’s ranch, Sheridan county, July 10. (128)

25

Sporobolus cryptandrus (Torr.) Gray.
Cherry county, July 21. (107)
Sporobolus cuspidatus (Torr.) Serib.
Cherry county, July 14. (109)
Agrostis hiemalis (Walt.) BSP.
Dry valley, Sheridan county, July 9. (119)
Calamovilfa longifolia (Hook.) Hack.
Antelope county, August 2. (120)
Calamagrostis stricta Trin.
Sheridan county, July 11. (252)
Bouteloua oligostachya (Nutt.) Torr.
Broad fields in the valley of the North Loup, Cherry county,
July 24. (105) These broad places in the valley of the
North Loup are miniature prairies with all the character-
istics of dry valleys. The narrow places in the valley are
wet and marshy.
Bouteloua hirsuta Lag.
Sand hills, valley of the Gordon, July 24.
Bulbilis dactyloides (Nutt.) Raf.
Prairies, Box Butte county, July 7. (113) Dry valleys,
Sheridan county.
Phragmites vulgaris (Lam.) BSP.
Dad’s Lake, July 26.
Munroa squarrosa Torr.
In blow-out near the forks of the North Loup, Cherry
county, July 21. (127)
Koeleria cristata (L.) Pers.
Box Butte county, July 7; Holt county, July 31. (121)
Eatonia obtusata (Michx.) Gray.
Shallow pond, Oxyoke ranch, Sheridan county, July 13.
(110)
Eatonia obtusata (Michx.) Gray var. robusta Vasey.
“Cherry county, July 22. (100)
Catabrosa aquatica (L.) Beauv.
Margins of cold spring in wet valley, Dye’s ranch, Cherry
county, July 19. (104)

26

Eragrostis multiflora (Forsk. ) Aschs.
Brown county, July 28. (102)
Distichlis spicata (Iu.) Greene var. stricta Thurber.
Low prairie, Box Butte county, July 7; wet valley (alkaline )
Sheridan county, July 9. (116)
Poa compressa L.
Sheridan county, July 9. (122)
Redfieldia flexuosa (Thurber) Vasey.
Antelope county, August 1. (207) Blow-outs throughout
the region.
Festuca octoflora Walt.
Box Butte county, July 7. (115)
Festuca ovina L.
Box Butte county, July 7. (111)
Bromus ciliatus L.
Cherry county, July 22. (108)
Agropyrum glaucum (Desf.) R. & S. var. occidentale Vasey
& Scribner.
Box Butte county, July 6. (126)
Hordeum jubatum WL.
Dry valleys, Sheridan county, July G. (118)
Elymus canadensis ML.
Wet valleys at head of North Loup and in central Cherry
county, July 19, 23. (108)
Cyperus aristatus Rottb.
Sheridan county, July 12; Cherry county, July 19. (245)
Wet valleys throughout the region.
Scirpus lacuster L.
Cherry county, July 27. (238) Wet valleys at head of

North Loup and in the lake region Grows very tall,
often twelve feet.

Carex douglasit Boott.
Sheridan county, July 12; valley of Pelican Lake, Cherry
county, July 26. (236)
Typha latifolia L.

Wet valleys along the North Loup, Cherry county, July 20.

27

Sparganium eurycarpum Engelm.
Wet valleys at head of North Loup and near the falls, July
20. (224)
Lemna minor L.
In old channel of the North Loup, Cherry county, July 22.
(272)
Lemna trisulea L.
Wet valleys near the head of the North Loup in small ponds.
July 19; Marsh Lake, July 26. (260)
Alisma plantago L.
Wet valleys near the North Loup, July 20, in the North
fork, July 2.. (283)
Sagittaria variabilis Engelm. var. angustifolia Gray.
In the north fork of the North Loup, July 21. (232)
*Sagittaria variabilis Engelm. var. diversifolia Gray.
Small pond in wet valley, Oxyoke ranch, Sheridan county,
July 13. (235)
Triglochin maritimum L.
Wet valley, Sheridan county, July 9. (226)
Potamogeton natans L.
In lake, Hannah’s ranch, Cherry county, July 27. (228)
Potamogeton pectinatus L.
With the preceding (229)
Potamogeton heterophyllus Schreb. var. graminifolius Gray.
Ponds along the North Loup, Cherry county, July 20.
(234)
*Naias flexilis (Willd.) Rostk & Schm.
With the preceding (231)
Ruppia occidentalis Wats.
Small pond in a wet valley, Sheridan county, July 10.
(230)
Selaginella rupestris (L.) Spreng.
High prairie, Brown county, July 28. (271) *
Marsilia vestita Hook. & Grev.
Small ponds, Box Butte county, July 7. (275)

28

Aspidium thelypteris (L.) Sw.
Wet valleys at the head of the North Loup, July 19; falls of
the North Loup, July 22. (278)
Onoclea sensibilis L.
With the preceding (277)
Cystopteris fragilis (L.) Bernh.
Canons, Long Pine, July 29. (270)
Marchantia polymorpha L.
Banks of tne North Loup at the falls, July 22. (274)
Chara fragilis Desv.
In small lake, Cherry county, July 19. (262)
Chara contraria A. Br.
Ponds in wet valleys, Cherry county, July 17, 18. (263)
*Chara foetida A. Br. var. longibracteata A. Br.
Ponds in wet valleys, Sheridan county, July 12, 13. (264)
Chara coronata A. Br.
In a small lake, Cherry county, July 18. (265)
Simblum rubescens Gerrard.
Sand hills, Cherry county, July 15. (2738)
Aecidium compositarum Mart. var. helianthi Burrill.
On Helianthus rigidus, Cherry county, July 19. (3)
Aecidium compositarum Mart. var. lygodesmiae Webber.
On Lygodesmia juncea, Sheridan county, July 9. (12)
Aecidium compositarum Mart. var. liatridis Webber.
On Laciniaria squarrosa var. intermedia, Sheridan county,
July 13. (6)
Aecidium jamesianum Pk.
On Asclepias speciosa, Cherry county, July 19. (7) On
Asclepias arenaria, Cherry county, July 15. (9)
* Aecidiwm chenopodii-fruticosi DC.
On Chenopodium leptophyllum, Sheridan.county, July 9.
(Does not entirely agree with Ae. ellisii Tracy & Gall.
It agrees well with specimens of Ae. chenopodii-fruti-
cost in Mycotheca Universalis No. 1028. Ae. ellisti and Ae.
chenopodti-fruticosi are not very unlike. Be)

29

Phragmidium subcorticium (Schrank) Wint.
On fosa virginiana var. arkansana, Sheridan county, July
12. (13)
* Phragmidium potentillae (Pers.) Karst.
On Potentilla pennsylvanica var. strigosa, Sheridan county,
July 12. (15)
Gi mnosporangium clavariforme (Jacq.) Rees.
Spermagones on Amelanchier alnifolia, Long Pine, July 29.
5)
Puccinia helianthi Schw.
On Helianthus annuus, Cherry county, July 25. (1)
Puceinia rubigo-vera (DC.) Wint.
On wheat in a small patch near a ranch, Cherry county, July
25. (2)
*Puccinia troximontis Pk.
On Troximon cuspidatum Sheridan county, July 12. (21)
Hardly distinct enough from P. hieracii (Schum.) Mart.
See Ellis N.A.F. no. 1452. P.)
*Puccinia physalidis Pk.
On Physalis virginiana, Sheridan county, July 12. (20)
Paccinia thesii (Desv.) Chaill.
I. On Comandra pallida, Cherry county, July 15. (282)
(Fide Webber in Catalogue, the aecidiwm of ‘this species.
It agrees sufficiently with de. pustulatum Curt. P. )
* Puccinia solidaginis Pk.
On Solidago speciosa var. rigidiuscula, Cherry county, July
15. (18)
Uromyces trifolii (A. & 8.) Wint. f. glycyrrhizae E &. E.
On Glycyrrhiza lepidota, Sheridan county, July 8. (11)
Uromyces fabae ( Pers.) DBy.
On Lathyrus sp. (ornatus?), Cherry county, July 14. (19)
Melampsora farinosa (Pers.) Schroet.
On Sulix tristis, Cherry county, July 27. (22)
Fuoascus prunt Fkl.
On Prunus pumila, Sheridan county, July 12. (24)

30

Septoria prunt Ell.
On Prunus demissa, Cherry county, July 26. (4)
* Septoria lobeliae Pk.
On Lobelia spicata, Cherry county, July 26. (16)
Kellermannia yuccigena BK. & ¥.
On dead leaves of Yucca glauca, Sheridan county, July 11.
(14)
Cercospora teucrii HE. & K.
On Teucrium sp. (occidentale?), Cherry county, July 26.
(10)
Cercospora pentstemonis HK. & K.
On Pentstemon grandiflorus, Brown county, July 29. (281)
Cercospora symphoricarpi E. & E.
On Symphoricarpos occidentalis, Sheridan county, July 11.
(17)
*Ramularia decipiens E. &. E.
On Rumex venosus, Box Butte county, July 7. (25)
Marsonia martini Sace. & Ell.
On Quercus macrocarpa, Long Pine, July 29. (23)
Coleochaete orbicularis Pringsh.
On Lemna trisulca, Cherry county, July 19. (261)
Coleochaete irregularis Pringsh.
On Chara contraria, Cherry county, July 19. (268)
* Bulbochaete mirabilis Wittr.
On Chara foetida var. longibracteatu, Sheridan county, July
12. (267)
*Oedogonium stagnale Kg.
In shallow pond in wet valley, Sheridan county, July 1).
269)
Nostoc commune Vauch.
On the ground and in shallow ponds in a pass between two

wet valleys, Cherry county, July 15. (266) Forms dense
masses of considerable size.

31

IL.

NorvEs ON THE CANON FLORA oF Sioux County, Wit List or PLANts CoL-
LECTED IN JULY AND August, 1892, By A. F. Woops.

Sioux county is the northwest corner county of Nebraska. It
is drained to the northeast by Hat creek with its tributaries, the
Long Branch, Sand, Dry, Sowbelly, Warbonnet, Squaw, and An-
telope. These tributaries radiate trom the principal stream in such
a way as to present the appearance of a fan. The line of the di-
vide between Hat creek valley and the White river couatry be-
gins at the northeast corner of the county and passes southwest,
almost directly towards the southwest corner of the county, to
near Andrews, on the Fremont, Elkhorn and Missouri Valley
railroad. From this point the general trend of the canon coun-
try is slightly northwest. Hat creek basin is several hundred
feet below the level of the table land to the south.

The creeks have their sources in canons, which generally have
the same name asthe creek. In most cases the canons proper
are cut and divided by many smaller side canons, sometimes
very narrow and deep, having a rivulet at the bottom, fed by a
spring at the head of the canon and by smaller springs at the
side.

In nearly all cases the sides of the canons are covered with a
rather dense growth of pine—Pinus ponderosa var. scopulorum.
Juniperus virginiana occurs here also. Higher up, along the
buttes, a prostrate form of Juniperus communis is very common.
Lower down, the monotony of the pine forest is broken by the
general intermingling of Ulmus americana (comparatively large
trees, sometimes two or three feet in diameter), Acer negundo,
Populus monilifera, P. tremuloides, Ostrya virginiana, Hraxi-
nus viridis, Betula occidentalis, and Acer glabrum. The latter
is usually a small tree, but in Squaw canon I found an individ-
ual about four inches in diameter and from fifteen to eighteen
feet high. Purthenocissus quinquefolia and Humulus lupulus
often by twining in and out among the underbrush and trees
make dense jungles, difficult to penetrate.

32

Along the brooks in the wider canons is a dense growth of wil-
low, mostly Salix nigra. Lepargyraea argentea is often seen
along the upper edges of the draws further out in the valley.
Everywhere in the canons is the smooth gooseberry, Ribes owy-
canthoides, which has very large and fine fruit. R. cereum, R.
floridum, and R. awreum are also quite common. Along the up-
per parts of the canons, and in open places, Rhus canadensis
var. trilobata grows in dense patches, and everywhere, on high
and low ground, in shade and in sun, in dry and in damp places,
is Rhus radicans. For some reason, perhaps on account of its
firmer leaves, it does not appear to be as poisonous as the ivy
found in the eastern part of the state. Prunus demissa and
Amelanchier alnifolia are common on the sides of the canons.
Along the sides of the buttes and well up the sides of the
canons is the little Symphoricarpos racemosus var. pauciflorus,
and extending down into the canons is the larger S. occidentalis:

Among the most conspicuous of the herbaceous plants on the
sides and tops of the buttes and canons are Pentstemon glaber,
P. gracilis, Cumpanula rotundifolia, Calochortus nuttallit and C.
gunmsoni, and Zygadenus elegans. All of these extend well
down into the canons. Phacelia circinata and Gilia iberidifolia
are confined to the upper edges of the canons and sides of the
buttes. Here are found a large number of prairie species, ex-
tending down into the valley, or so-called bad land region.
Down in the damper portions of the canons, among many others,
are Habenaria hyperborea, H. bracteata, Coralorrhiza mulli-
flora and C. striata, and Spiranthes romanzoffiana. Pterospora
andromedea is common in the narrower canons, under the pines.

LIST OF PLANTS COLLECTED.

(Species designated by a * not previously reported. )

Eupatorium purpureum L, Squaw canon. (352)
Chrysopsis villosa Nutt. var. hispida Gray. Squaw butte. (346)
Haplopappus nuttallii Torr. & Gray. Squaw butte. (347)

38

Haplopappus spinulosus (Parsh) DC, Squaw eanon. (337)
Solidago missouricnsis Nutt. var. moufana Gray. Squaw canon.
(345)

Townsendia grandiflora Nutt. Squaw butte. (341)

Brigeron glabellus Nutt. var, mollis Gray. Squaw canon. (345)

Erigeron pumilus Natt. Squaw butte. (344)

Rudbeckia angustifolia (DC.) Benth. & Hook. Buttes. . (355)

Rudbeckia columnaris Pursh. Buttes near Squaw canon. (354)

Rudbeckia columnaris Parsh var. puleherrima (DC.) Torr &
Gray. With the preceding. (253)

Helianthus annuus L, Squaw canon. (350)

Helianthus rigidus (Cass) Desyv. Fields around Squaw butte.
(349)

Hymenopappus filifolius Hook. Squaw canon. (855)

Actinella acaulis (Parsh) Nutt. Squaw butte. (840)

Crepis glauca Torr. & Gray. Squaw canon. (353)

Achillea millefolium L. Squaw canon. (343)

Cnicus undulatus (Nutt.) Gray. Bad lands near Squaw butte.
(348)

Lactuea canadensis L. Squaw canon. (359)

Lactuca pulchella (Nutt.) DC. Fields around Squaw canon.
(342)

Lygodesmia juncea (Pursh) Don. In valleys. (356)

Slephanomeria minor DC. Bad lands. (357)

Symphoricarpos occidentalis (R.Br.) Hook. Squaw canon. (312)

Symphoricarpos racemosus Michx. var. panciflorus Robbins
Squaw butte. (417)

Galium aparine L. Squaw canon. (318)

Galium boreale L. Squaw canon. (317)

Galium triflorum Michx. Squaw canon. (316)

Campanula rotundifolia L. ‘ Squaw canon. (820)

Asclepias speciosa Torr. Squaw canon. (366)

Asclepias verticillata L. var. pumila Gray. Squaw canon. (365)

Fraxinus viridis Michx. Squaw canon. (313)

34

Plantago patagonicu Jacq. var. gnaphalioides (Nutt.) Gray.
Lowlands near canons. (329)

Phryma leptostachya L. Squaw canon. (314)

Mentha canadensis L. var. borealis (Michx.) Wood. Squaw
canon. (323)

Vleekia foenicula (Pursh) Raf. Squaw canon. (324)

Aphyllon ludovicianum (Nutt.) Gray. Buttes near Squaw canon.
(335)

Orthocarpus luteus Nutt. Squaw canon. (831)

Veronica americana Schw. In spring, Squaw canon. (315)

Pentstemon glaber Pursh. Buttes near Squaw canon. (33+)

Pentstemon gracilis Nutt. With the preceding. (333)

Physalis lanceolata Michx. Around Squaw canon. (830)

Krynitzkia glomerqta (DC.) Gray. Buttes. (325)

Krynitzkia jamesti (Torr.) Gray. With the preceding. (326)

Phacelia circinala Jacq. Buttes near Squaw canon. (327)

Gilia iberidifolia Benth. Buttes near Squaw canon. (328)

Steironema ciliatum (L.) Raf. Canons, (374)

Pirola secunda L, Squaw and Warbonnet canons. (319)

* Plerospora andromedea Nutt. Squaw and Warbonnet canons,
(309)

Comandra pallida A.DC. Squaw canon. (364)

aida lea Richardson. Upper edges of canons.

Lupinus plattensis Wats. Squaw prairie. (403)

Psoralea incana Nutt. With the preceding. (404)

Psoralea digitata Nutt. Prairies. (405)

Psoralea esculenta Pursh. Prairies. (412)

Psoralea lanceolata Pursh. Squaw butte. (408)

Psoralea tenuiflora Parsh. Squaw butte. (407)

Kuhniastera candida (Willd.) OK. Prairies. (414)

Kuhniastera purpurea (Vent.) MacM. With the preceding.
(402)

Astragalus gracilis Nutt. Squaw butte. (406)

Astragalus hypoglottis L. Squaw butte. (416)

35

Astragalus multiflorus Gray. Bad lands. (413)

Astragalus piclus Gray var. filifolius Gray. Squaw butte.
(415)

Spiesia lamberti (Pursh) OK. Squaw prairie. (401)

Glieyrrhiza lepidota Pursh. Squaw canon. (409)

Prunus demissa Walp. Squaw and Warbonnet canons. (389)

Geum album Gmelin. Squaw canon, (391)

Fragaria vesca L, Squaw canon. (390)

Potentilla arguta Pursh. Squaw canon. (392)

Agrimonia eupatoria L. Common in canons. Hat creek. (383)

Amelanchier aluifolia Nutt. Squaw canon. (394)

Epilobium adenocaulon Haussk. Squaw canon. (321)

Oenothera caespitosa Nutt. Buttes near Squaw canon. (375)

Oenothera serrulata Nutt. With the preceding. (377)

Gaura coccinea Nutt. Squaw butte. (379)

Ribes aurewn Pursh. Warbonnet canon. (398)

Ribes cereum Dougl. Near Warbonnet canon. (397)

Ribes floridum L’Her. Squaw canon. (400)

* Ribes oxycanthoides L. Common in all canons. (396)

Sedum stenopetulum Pursh. Buttes. (367)

Cornus pubescens Nutt. Squaw canon. (387)

Sanicnla marylandica L. var. cauadensis (L.) Torr. Squaw
canon. (385)

Musenium tenuifoliam Nutt. Bad lands. (388)

Osmorrhiza longistylis (Torr.) DC. Squaw canon. (387)

Euphorbia petaloidea Engelm. Buttes. (370)

Euphorbia montana Engelm. Buttes. (372)

Polygala alba Nutt. Prairie about Squaw canon. (411)

Acer glabrum Torr. Squaw canon. (378)

Rhus aromatica Ait. var. trilobata (Nutt.) Gray. Squaw canon.
(399)

Rhus radicans L. Everywhere throughout the region.

Malveopsis coccinea (Nutt.) OK. Squaw butte. (380)

Viola canadensis L, Squaw canon. (376)

Nasturtium officinale R.Br. Squaw canon. (303)

36

Lesquerella argentea (Pursh) MacM. Bad lands. (381)

Argemone platyceras Link & Otto. Squaw canon, (352)

Thalictrum purpurascens L. Squaw canon. (373)

*4etaca spicala L. var. arguta Torr. Squaw canon. (384)

Berberis repens Lindl, Squaw butte. (395)

Paronychia jamesii Torr, & Gray. Squaw canon. (360)

Arenaria franklinii Dougl. Squaw butte. (361)

Allionia hirsuta (Nutt.) Pursh. Squaw canon. (336)

Allionia nyctaginea Michx. vay. oblongifolia Gray. Squaw canon.
(332)

Abronia fragrans Nutt. Prairies near Squaw canon. (371)

Eviogonum annuum Nutt. Buttes and highlands. (368)

Eriogonum flavum Nutt. Buttes. (363)

*Eriogonum jamesti Benth. Bad lands. (362)

Rumex venosus Pursh. Fields and canons. (864)

Humulus lupulus L. Warbonnet canon. (311)

Parielaria pennsylvanica Muhl. Damp places in canons. (322)

Spirauthes romenzoffiana Cham. Squaw canon. (308)

Habenaria bracteata R.Br. Squaw canon. (306)

*Habenaria hyperborea R.Br. Squaw canon. (805)

Coralorrhiza mulliflora Nutt. Warbonnet canon, (307)

*Coralorrhiza striata Lind], Warbonnet canon, (300)

Yucca glauca Fraser. Squaw canon. (304)

Calochortus nutlallii Torr. & Gray. Squaw canon. (301)

Calochortus guinisonii Wats. Squaw canon. (302)

Zygadenus elegans Pursh. Squaw canon. (303)

Disporum trachysperimim (Wats.) Benth. & Hook. Squaw
canon. (310)

Spartina eynosuroides (L.) Willd. Creek banks in canons.
(432)

Phlewm pratense L. Canons, (421)

Oryzopsis cuspidata (Nutt.) Benth. Prairies. (418)

Agrostis asperifolia Trin. Warbonnet canon. (485) Deter-
mined by F. L. Scribner.

algrostis exarata Trin. Canons. (437)

BT

Calamovilfa longifolia (Hook.) Hack. Bad lands. (433)

Calamagrostis stricta Trin. Prairies around canons. (420)

Boutelona oligostachya (Nutt.) Torr. Valleys and bad lanjls
(428)

Bulbilis dactyloides (Nutt.) Raf. Prairies and bad lands. (428)

Koeleria cristata (L.) Pers. Prairies and edge of bad lands.
(424)

Eatonia obtusata (Michx ) Gray. Warbonnet canon. (436)

Distichlis spicata (.) Greene var. stricta Thurber. Ldge of
bad lands. (423)

Panicularia nervata (Willd.) OK. Canons. (427)

Bromus ciliatus L. var. purgans Gray. Canons. (430)

Agropyrum glaucum (Desf.) R. & 8. var. occidentale Vasey &
Scribner. Prairies. (434)

Agropyrum repens (.) Beauv. Common everywhere. (425)

Hordeum jubatum L, Common everywhere. (422

Elymus sitanion Schult. Bad lands. (42!)

Elymus striatus Willd. Canons. (£26)

Botrychium virginianum (L.) Sw. Squaw canon. (444)

Cystopteris fragilis (L.) Bernh. Squaw canon. (43!)

Woodsia oregona Eaton Squaw canon. (440)

Equisetum arvense L. Squaw canon. (+47)

Equisetum levigatum Braun. Squaw cavon. (445)

Equisetum robustum Braun. Squaw canon. (447)

Timmia megapolitana Hedw. Squaw canon, (438)

*Psathyrella fulvipes Mont. Sandy ground, Squaw canon.
(500)

*Deconica bullacea Bull. Squaw canon. (502)

*Psilocybe corneipes Fr. On ground, Squaw canon. (501)

Stropharia semiglobata Batsch. On horse dung, Squaw canon.
(503)

*Inoeybe lanuginosa Bull. On ground, Squaw canon. (504)

*Volvaria viscosa Clements n.sp. Warbonnet canon. (805)

Pileus fleshy, campanulate-convex, smooth, very viscous,

fulvous-ochraceous; stipe prominently bulbous, nearly

88

equal above, solid, smooth, ochraceous; volva ample, lobed,
concolorous; lamellae touching, brown; spores ovoid-
ellipsoid, dilutely flesh colored, with a large locule, 8x5
p. Pileus 6 cm. wide; stipe 6 cm. long, at base 14 cm.
wide, above } cm. Related to V. primulina Cooke &

Massee. C.
*Mycena acuto-conica Clements n.sp. In sand, Squaw canon.
(506)

Pileus slightly membranaceous, persistently conical, acute,
viscous, smooth, bright yellow; stipe long, equal, smooth,
yellowish-brown; lamellae free, linear, deep ochraceous
when dry; spores oblong-eiliptical, 12x7-S mw. Pileus 24
em. wide by 3 cm. high. Stipe 6-7 em. long. Distin-
guished by its persistently conical, bright yellow pileus,
and by the free ochraceous gills. ©.

Aecidinum clematidis DC, On Clematis ligusticifolia. (450)
Aecidium pentstemonis Sechw. On Pentstemon glaber. (455)
*Puccima anachoreta Ell. & Hark. On Calochorlus gunnisonii.
(451)
Puccima menthae Pers. On Monarda fistulosa. (459)
Cronartium asclepiadeum (Willd.) Fr. var. thesii Berk. On
Comandra pallida, (454)
Melampsora farinosa (Pers. ) Schroet. On Salix tristis, (452)
*Helvella infula Schaeff. In sand, Warbonnet canon. (507)
*Helvclla sulcata Afzel. In wet sand, Squaw canon. (508 )
*Septoria argophylla E. & K. On Psoralea incana. (457)
*Septoria grossulariae (Lib.) Westd. On Ribes aurewm. (456)
*Septoria trregularis Pk. On Rhus radicans. (453)
*Septoria podagrariae Lasch. On Osmorrhiza longistylis.
(458)
*Dothidea collecta (Schw.) Ell. On twigs of Celastrus *scan-
dens, Squaw canon. (510)
*Hypoxylon crustaceum (Sow.) Nits.

On twigs, Squaw canon.
(511)

30)

Kil.

MISCELLANEOUS ADDITIONS TO THE FLORA OF THE STATE, AND New or Note-
WORTHY SPECIES From Various LOcALities.

COMPOSITE.
Helenium nudiflovrum Nutt. Lincoln. (512)
VIOLACER,
Viola sagittata Ait. Fremont. (513)

RANUNCULACES.
Caltha palustris L. Norfolk. (514)
SALICACES.
Populus acuminata Rydberg, in Bulletin Torrey Botanical Club
XX., 46. Scotts Bluff county. (515)

(A new poplar, nearly related to the Balm of Gilead, P,
balsamifera, and the Black Cottonwood, P. angustifolia,
but distinguished by its leaves, which are green on both
sides, long petioled, cuneate at the base, and with a long
acumination. R.)

GRAMINEZ.
Paspalum leve Michx. Ashland. (516)
Cinna arundinacea L. Lincoln. (517)

FILICES.

Asplenium filix-foemina (L.) Bernh. Long Pine. (441)
BRYACER.
Physcomitrium hookeri Hampe. Valentine. (518)
AGALICINES.
Panaeolus campanulatus L. On horse dung, Lincoln. (519)
Coprinus granulosus Clements n. sp.

Pileus membranaceous, ovoid-oblong, at length campanulate,
closely radiate-sulcate, furfuraceous, pale yellowish-
brown, umbo prominent, translucent, flavo-fuscous, at first
covered with more or less persistent coarse brown gran-

40

ules; stipe white, hollow, equal, everywhere persistently
pruinose; lamellae ventricose, brown, finally black, touch-
ing, at length free; spores oblong-elliptical, brownish-pur-
ple, 1-2 guttulate, 8-10x5-6 y.
Pileus 24 cm. wide and high. Stipe 3 cm. x + mm.
On wet ground, in greenhouse, Lincoln. (520)
Coprinus lagopides Karst. In flower bed, Lincoln. (521)
Coprinus mycenopsis Karst. At base of stumps, Lincoln. (522)
Psathyra obtusata Fr. On damp ground, Lincoln. (523)
5)

Psathyra subnuda Karst. On wet ground, Lincoln. (524)
Psathyra helobia Kalchbr. On wet earth in greenhouse, Lincoln.
(525)

Psathyra falkii Weinm. On ground, Lincoln. (526)

Psathyra schulzeri Quel. On ground, Ashland. (527)

Psilocybe hebes Fr. On ground, Lincoln. (528)

Psilocybe comta Fr. In grass, Lincoln. (529)

Psilocybe cernua Vahl. In grass, Lincoln. (530)

Psilocybe uda Pers. On muddy ground, Lincoln. (531)

Paxillus chrysophyllus Trog. On pine railroad tie, Lincoln.
(532)

Galera pubescens Gill. On ground, Valentine. (533)

Galera tener Schaeff. In grass, Lincoln. . (534)

Naucoria centunculus Fr. On railroad ties, Lincoln. (535)

Hebeloma latericolor Mont. Wet ground at base of stumps Wa-
bash. (536)

Inocybe tuberosa. Clements n.sp.

Pileus expanded, squamose, flesh y, deep brown; stipe tuber-
ous, equal above, gilvous, lamellae rather few, adnexed,
deep brown; spores obtuse, ovoid-elliptical, apiculate at
one end, l-guttate, 6x4 ».

Pileus 3 cm. wide. Stipe 4 em. long; at base 10 mm, above
7 mm. wide. Related to I insequens Britz. Lincoln.

(537)

41

Pholiota speciosa Clements n.sp.

Pileus fleshy, plano-convex, squamose, umbonate, dirty-
white; stipe fistulose, thick, equal, white; annulus small,
white; gills free, crowded, soot colored; spores umber,
ovoid, 1-2-guttate, 5x34 4, Pileus 4-6 cm. wide; stipe 5
em. long. Related to P. gibberosa Fr.

On ground, in woods, Wabash. (538)

Pholiota praecox Pers. var. minor Batl.

In grass, Lincoln. (439)

Marasmius acicularis B. & C. On dead wood, Valentine. (540)

Marasmius rotula (Scop.) Fr. On tree trunks, among moss,
Elmwood, Lincoln.. (541)

Russula emetica Fr. Ob ground, Milford. (542)

Pleurotus linpidoides Karst. On decaying stumps, Lincoln.

(543)

Tricholoma impolitum Lasch. In wet saw dust, Lincoln.
(544)

Tricholoma favillare Fr. On ground in greenhouse, Lincoln.
(545)

Tricholoma georgu Fr. On ground, Lincoln. (546)
Lepiota avellanea Clements n.sp.

Pileus fleshy, dry, plane, drab-colored, cuticle lacerate
toward the margin, forming appressed brown scales; stipe
somewhat hollow, bulbous, brownish-fibrillose; annulus
small, fleshy, concolorous, fixed, inferior; lamellae remote,
attached to an indistinct collar, cream-colored, becoming
reddish with age; spores irregularly ovate, acute at one
end, 8-10x5-6 y.

Pileus 5 cm. wide, stipe 4 em. long by 8 mm. wide. On
ground in greenhouse, Lincoln. (547)

Lepiota naucina Fr. Damp ground in woods, Elmwood. (548)
Lepiota implana Berk. On ground, Lincoln. (549)
Lepiota boudieri Bres. On ground, Lincoln. (550)

: HYMENOGASTRACEA.
Phlyctospora fusca Corda. Lincoln. (551)

42

UREDINEZ.

Puceinia cladophila Pk. II. and IIT. on Slephanomeria minor,
Scott’s Bluff county. (26)

Puceinia hieracii (Schum.) Mart. On Cnicus undulatus, Scott’s
Bluff county. (27)

Puceinia microsperma B. & C. On Lobelia syphilitica, Lincoln.
(1042) Not previously reported from eastern Nebraska.

Uromyces caryophyllinus (Schrank.) Schroet On Dianthus
sinensis in greenhouse, Lincoln. (1127) Determined
by Dr. Bessey.

PEZIZE.E,

Sclerotinia tuba Batsch? Lincoln. (552)

(As the specimens correspond to the very meager descrip-
tions of S. tuba, I have referred them to that species pro-
visionally. JI append a description of them: Cups in-
fundibuliform, arising from a black sclerotium, 1 cm. in
diameter, soot-black, smooth, thin; stipe long, black, cori-
aceous, striate when dry, 4 cm. by 4-5 mm., gradually

; widening into the cup; asci cylindrical, 8-spored, 200x16

Si p. Cups 24-3 em. wide by 2-25 em. high. C.)

Helotium sulfurellum E. & KE. On dead limbs, Elmwood, Syra-

cuse. (953)

Neotticlla calichvoa Boud. On earth in flower pot, Lincoln, (554)

Lachnea leeticolor Karst. On fallen leaves, Lineoln. (555)

Lachnea fissilis Sace. & Cke. On wet boards in greenhouse,

Lincoln. (556)
Humaria rufilans Fy. On ground with moss. Lincoln, (567)
Peziza sepiatra Cke. On earth in greenhouse, Lincoln, (568)
Peziza vesiculosa Bull, var. minor Sacc. On wet wood in
greenhouse, Lincoln. (564)

Geopyxis carbonaria A. & 5. On damp ground in woods, Lin-
coln. (570)

Geopyxis pallidula C. & P. On wet sand and wood in green-
house, Lincoln. (571)

43

Geopyxis tuberculosa Sace. & Cke. On damp ground in hot-bed,
Lincoln, (572)

SPHAEROPSIDEE.
Septoria verbenae Rob. On Verbena hastuta, Lincoln. (1024)
MELANOONIEE.

Gloeosporium musarum Cke, & Massee. On bananas, Lincoln.
(573)

(G. lagenurium (Pass.) Sacc. var. musarum E. & E., in
Journ. of Mycol. V. 155. The latter described by Ellis
and Everhart in 1889, from specimens collected by me ap-
pears to be the same as G. musarum described, from spec-
imens collected in Australia, ia Grevillea NVI. 3, (1887)
Conidia long-ellipsoid, rounded or sometimes pointed,
74-11x3-4 », As is said by Ellis and Everhart 1. ¢., scarcely
diifers from G. lagenarinm. P.)

DEMATICEA.,

Cercospora brunkii Ell. & Gal. On Pelargonium sp.(cultivated)
Lincoln. (1126) Determined by Dr. Bessey.

DOTHIDIACE®.
Dothidea collecta (Schw.) Ell. On decaying stems, Lincoln. (574)
HYPOCREACE.

Megalonectria caespitosa Speg. On block of wood supporting a
south-Mexican orchid in greenhouse, Lincoln. (1125)
This species was discovered by Spegazini in Brazil on frag-
ments of wood, and does not seem to have been reported
since. The block on which it was growing was an or-
dinary one picked up about the greenhouse, and it seems
probable that the orchid was responsible for the presence

of the fungus.
SPELERIACEA.

Phomatospora berkleyt Sacc. On stems of Sambucus canaden-
sis, Saltillo. (575)

44

Trichosphaeria pulchriseta (Pk.) Ell. On herbaceous stems,
Saltillo. (576)

Hypoxylon perforatim (Schw.) Sace. On twigs of Acer ne-
gundo, Saltillo. (577)

ERYSIPHEA.

Erysiphe cichoracearum DC. OnVerbena bracteosa,Crete (1091) ;
on Ambrosia artemisifolia, Crete (L094); on Tragopogon
porrifolius, Crete. (1099)

Erysiphe communis (Wallr.) Fr. On Oenothera biennis, Crete
(1095); on Thalictrum purpurascens, Crete (1098); on
Amphicarpaea comosa, Crete. (1100)

Erysiphe galeopsidis DC. On Scutellaria lateriflora, Crete.
(1084); on Stachys palustris, Crete. (1085)

Microsphaera elevata Burrill. On Catalpa speciosa, Crete.

(1115)

Microsphaera quercina Schw. On Quercus macrocarpa, Crete.
(Ls |

Microsphaera russellii Clinton. On Ovalis stricta, Crete.
(1114)

Uneinula circinata Pk. On Acer saccharinum, Crete. (1104)

Uncinula necator (Schw.) Burrill. On Vitis riparia, Crete
(1103); on Vitis sp. (cult’d) Crete. (1107)

Phyllactinia suffulta (Reb.) Sacc. On Framxinus viridis, Crete.
(1120)

Sphaerotheca castagnei Lévy. On Bidens frondosa, Lincoln
(1023), Crete (1102); on Bidens levis, Crete. (1113)

CLADOPHORACE.E.
Chaetophora pisiformis (Roth.) Ag. Minden. (578)

ULOTRICHACE,

Conferva affinis Kg. Lincoln. (579)
Microspora abbreviata (Rabh.) Lagerh. Lincoln, (580)

45

DESMIDIACE.E.

Sphaerozosma filiforme Rabh. Minden. (581)

Pleurotaentum nodulosum DBy. Minden. (582)

Cosmarium leve Rabh. var. septentrionale Wolle. Minden.
(583)

Cosmarium granatum Bréb. Minden. (584)

Cosmarium subcrenatum Hantzsch. Minden. (585)

Cosmarium tinctum Rabh. Minden. (586)

Staurastrum crenulatum (Delp.) Naeg. Minden. (587.)

DIATOMACES.

Navicula tabellaria Kg. Minden. (588)
Navicula cuspidata Kg. Minden. (589)
Navicula gibba Kg. Minden. (590)

Navicula viridula Kg. Minden. (591)
Navicula viridula Kg. var. minor Kg. Minden. (593)
Navicula tenela Bréb. Minden. (592)
Stauroneis smithii Grun. Minden. (594)
Pleurosigma kuetzingii Grun. Minden. (595)
Amphiprora alata Ehrb. ‘Minden. (596)
Cymbella turgidula A.Schm. Minden. (597)
Amphora libyca Ehrb. Minden. (598)
Gomphonema olivaceum Ehrb. Minden. (599.)
Gomphonema lagenula Kg. Minden. (600)
Gomphonema intricatum Kg. Minden. (601)
Gomphonema parvulum Kg. Minden. (602)
Nitzschia coarctata Grun. Minden. (603)
Nitzschia gracilis Hantzsch. Minden. (604)
Nitzschia palea (Kg.) W. Sm. Minden. (605)
Suriraya saxonica Auersw. Minden. (606)
Suriraya spiralis Kg. Minden. (607)
Suriraya norvegica Kulenst. Minden. (608)
Suriraya euglypta Ehrb. Minden. (609)
Fragilaria entomon Ehrb. Minden. (610)
Fragilaria capucina Rabh. Minden. (611)

46

Fragilaria mutabilis Grun. Minden. (612)
Eunotia parallela Ehrb. Minden. (613)
Eunotia major Rabh. Minden. (614+)
Cymatopleura elliptica W.Sm. Minden. (615)

PALMELLACE®.
Pediastrum tetras (Ehrb.) Ralfs. Lincoln. (616)
BACTERIACES.

Beggiatoa arachnoidea (Ag.) Rabh. Lincoln. (617)
Leptothrix calcicola Kg. Lincoln. (618)
NOSTOCACER.

Sphaerozyga smithit Thwaites. Lincoln. (619)

Cylindrospermum limnicola Kg. Lincoln. (625)
OSCILLARIACED.

Oscillaria violacea Wallr. Lincoln. (620)

Oseillaria antliaria Juerg. Lincoln. (621)

Oscillaria tenerrima Kg. Lincoln. (622)
CHROOCOCCACES.

Chroococcus rufescens (Bréb.) Naeg. Lincoln. (623)
Gloeocapsa arenaria Rabh. Lincoln. (624)

UNIVERSITY OF NEBRASKA.

BoTaNICAL SURVEY OF NEBRASKA.

Conducted by the Botanical Seminar.

LUT.

REPORT FOR 18938.

LIncoun, NEBRASKA, U.S. A.
Published by the Seminar.
1894.
(Distributed June 18, 1894.)

CONTENTS.

DIME ou Guoinmehe Sica tage a geases eyes ee eeeuahaeY 4
Additions to the Reported Flora of Nebraska made during

1S hee Wee ia tevald caked eee eed ouuwansawad 5
A Revision of the Nomenclature of the Nebraska Polypetale,

by Pi As Ry G bere case ceey ase wae wane aaa siete .... 20
Preliminary List of Botanical Expeditions made in Aietixaska,

by Frederick EH. Clements............0 02. .-2..0005: 39

Bibliography of the Flora of Nebraska, by Roscoe Pound... 43

NOTE.

The principal collections made during the year 1893 were
three. Messrs. Woods and Saunders collected in the Republican
valley from the Colorado line eastward, and also on the Little
Blue. Mr. Rydberg spent the entire summer in the sandhill re-
gion, principally along the Dismal river. Mr. Clements spent
the entire summer in northeastern Nebraska, beginning at Emer-
son, in Dakota county, and collecting along the Missouri and Ni-
obrara to Meadville, in Brown county. The last two collections
were made possible by the United States Department of Agricul-
ture which undertook them jointly with the Survey.

The thanks of the Seminar are also due to Rev. J. M. Bates,
of Valentine, Dr. H. Hapeman, of Minden, and to Mr. C. A.
Turrell, Mr. Chas. Engberg, and Misses Cora F. Smith and
Louise Lee, students in the Department of Botany at the Univer-
sity, for collections or additions to the reported flora.

ADDITIONS TO THE REPorTED Fiona OF NesraskA Mapr Durina
1893.

*Indicates new host only.

*Phytomyxa leguminosarum (Frank) Schroeter.
On Falcata comosa, Cushman. (4044)
On Dalea dalea, Bellevue. (3225)
Lampropedia littoralis (Oerst.) DeToni and Trevisan.
Stagnant water in salt marshes, Lincoln. (3380)
Merismopedia convoluta Breb.
South Bend. (38376)
Scytonema cinerewm Menegh.
Lincoln. (3381)
Scytonema hoffmani Ag.
Lincoln. (8382)
Stigeoclonium tenue Kuetz.
Lincoln. (3377)
Hormiscia flaccida nitens (Menegh.) Hansg.
In Greenhouse, Lincoln. (3378)
Closterium acuminatum Kuetz.
Lincoln. (3383)
Closterium lanceolatum Kuetz.
Lincoln. (3384)
Cosmarium gottlandicum Wittr.
Lincoln. (3385)
Cosmarium ralfsti Breb.
South Bend. (3386)
Staurastrum pseudopachyrinchium Wolle.
South Bend. (3387)
Spirogyra grevilliana (Hass.) Kuetz.
Lincoln. (8379)

6

Spirogyra tenuissima (Hass.) Kuetz.
Lincoln. (3390)
Spirogyra varians (Hass.) Kuetz.
Lincoln. (3391)
Vaucheria aversa Hass.
Lincoln, (3388)
Vaucheria terrestris Lyngb.
Minden. (3389)
Vaucheria tuberosa A. Br.
Saltillo. (3392)
*Peronospora parasitica (Pers.) DeBary.
On Roripa palustris. Bellevue. (3108)
Plasmopara halstedii (Farlow) Berlese & DeToni.
On Silphium perfoliatum, Lincoln. (3178)
Batrachospermum gelatinosum (L.) Woods.
Bellevue. (3393)
Chantransia violacea Kuetz.
Bellevue. (3394)
*Sphaerotheca pannosa (Wallr.) Lev.
On Rosa multiflora (cultivated), Lincoln. (4000)
*Erysiphe cichoracearum DC.
On Helianthus decapetalus, Lincoln. (3168)
Nitschkia tristis (Pers.) E. & E.
On decaying branches, Saltillo. (3249)
Fracchiaea heterogenea Sacce.
On log, Lincoln. (3270)
Coronophora annexa (Nits.) Fkl.
On dead limbs, Saltillo. (3268)
Diatrype albo-pruinosa (Schw.) Cooke.
On dead oak limbs, Saltillo. (3269)
Hypoxylon colliculosum (Schw.) Berk.
On log, Cedar Bluffs. (3274)
Hypoxylon marginatum (Schw.) Berk.
On dead limbs, Saltillo. (3396)

7

Hypoxylon stigmateum Cooke.

On oak, Lincoln. (8271)
Nummularia repanda (Fr.) Nits.

On oak, Saltillo. (3275).
Nummularia bulliardiit Tul.

On dead limbs, Saltillo. (33897)
Chaetomium bostrichodes Zopf.

On rotting cloth, Lincoln. (3398)
Trichosphaeria socia Sace.

On dead limbs, Saltillo. (3240)
Didymosphaeria accedens Sace.

On dead twigs, Saltillo. (3252)
Amphisphaeria pseudo-wmbrina Sace.

On Ostrya ostrya, Cedar Bluffs. (3239)
Valsaria insitiva (Cesati) De Not.

On Gleditsia triacanthos, Saltillo. (38242)
Valsaria foedans (Karst.) Sace.

On decaying twigs, Saltillo. (38394)
Melanomma cupularis Clements, n.sp.

Perithecia generally forming a thin crust, sometimes scat-
tered, superficial, globose, varying to disciform, finally
cupulate, slightly roughened, black, small, 250-300 yp;
ostiolum inconspicuous; asci lacking; spores oblong,
straight, or curved; ends obtuse, tri-septate; end cells trun-
cate-globose, hyaline; interior cells oblong fuscous, uni-
guttate, 25-28x5-6 ». Onstump, Saltillo. (8255)

Pleospora saccardiana Roum.

On Fraxinus viridis, Saltillo. (3243)
Cucurbitaria kelseyi E. & EH.

On dead branches, Cedar Bluffs. (3254)
Ophiobolus fulgidus (C. & P.) Sace.

On dead sunflower stalks, Saltillo. (3251)
Gloniopsis australis (Duby ) Sace.

On oak, Saltillo (38272)

8

Hysterographium variabile (C. & P.) Sace.
On decorticated stump, Saltillo. (3395)
Hysterographium mori (Schw.) Rehm.
On twigs, Saltillo. (3399)
Pezizerivularis Clements, n.sp.
Sessile, carnose, explanate or slightly concave, margin
strongly raised; hymenium umber, without blackish
. brown, minutely verrucose; asci cylindrical, not becom-
ing blue at tip with iodine, 250x20 yw; paraphyses few,
hyaline, granular, 5-6 4; sporidia broadly ellipsoid, mon-
ostichous, with two large guttae (10 yu in diameter), 25-
26x15-16 yp.
On immersed branches in streams, Meadville. (2991)
Discina venosa rabenhorstit Cooke.
On wet branches, Meadville. (2990)
Sarcoscypha coccinea (Jacq.) Fr.
On dead limbs, Lincoln. (3226)
Lachnea theloboloides Alb. & Schw.
On bark, Saltillo. (3266)
Ciboria tabacina Ell. & Holw.
On dead limbs, Saltillo. (4153)
Mollisia cinerea canella Karst.
On dead limbs, South Bend. (8277)
Mollisia stictella Sace. & Speg.
On bark, Saltillo. (3262)
Trichopeziza subochracea (C, & P.) Sace,
On sunflower stalks, Saltillo. (3261)
Cenangium populneum (Pers.) Rehm.
On Quercus rubra, Bellevue. (2996)
Schyzorylon bagnisianum Speg.
On decaying twigs, Saltillo. (2997)
Lecanidion atratum (Hedw.) Rabh.
On decorticated ash trees, Saltillo. (3260)

9

Blitrydium megalosporum Clements, n.sp.
Ascoma patellate, sessile, carbonaceous, black, 4 told mm. ;
dise black, plane, or strongly convex, margin more or less
convex; asci long clavate, nearly sessile, 8-spored, 140-
175x30-40 yw; spores elliptical oblong, brownish yellow,
attenuated both ways but obtusely rounded at the ends,
inequilateral, with 12-15 transverse septa and 5-7 longi-
tudinal interrupted septa, becoming fenestrate muriform,
distichous, not constricted, 50-72x20-25 »; paraphyses
colorless, clavate, furcate above.
On decorticated twigs of Fraxinus viridis Saltillo. (2998)
Puccinia angustata Pk.

On Cyperus esculentus, Kennedy. (3284)

On Scirpus atrovirens, Saltillo. (3296)
*Puccinia caricis (Schum.) Rebent.

On Cyperus houghtonti,, Thomas county. (3317)
* Puccinia helianthi Schw.

On Heliopsis scabra, Bellevue. (3208)
Puccinia lygodesmiae E. & E.

On Lygodesmia juncea, Arapahoe. (2208)
*Puccinia petalostemonis Farlow.

I. and II. on Kuhniastera purpurea, Lincoln. (3360, 3090)
* Puccinia silphii Schw.

On Silphium perfoliatum, Lincoln. (3176)
Puccinia porri (Sow.) Winter.

I. on Allium mutabile, Lincoln. (3353)
*Puccinia pimpincllae (Strauss) Lk.

III. on Peucedanum foeniculaceum, South Bend. (3352)
* Aecidium compositarum Mart.

On Rudbeckia angustifolia, Lincoln. (3096)
* Aecidium clematidis DC.

On Clematis virginiana, Lincoln. (3357)
* Aecidium jamesianum Pk.

On Asclepias tuberosa, Lincoln. (3356)

10

Aecidium phrymae Halst.
On Phryma leptostachya, Thomas county. (3303)

* Aecidium oxalidis Thuem.
On Oxalis stricta, Lincoln. (3363)

Tilletia montana EH. & E.
On Redfieldia flecuosa, Hooker county. (4055)
Tilletia tritic: (Bjerk.) Winter.
On wheat from the Republican valley. (3267) Spores
reticulate.

Phoma pustulata Sace.
On dead maple branches, Saltillo. (3136)

Sphaeropsis gleditschivicola Cooke.
On Gleditsia triacanthos, Saltillo. (8006)
Sphacronema longirostris Clements, n.sp.
Perithecium innate, with a long, stout, cylindrical beak,
breaking through the cortex, black, globose, cespitose 1-
14 mm. diam.; spores fusiform, elongate, slightly curved,
2-nucleate, 20x3 p.
In living branches of Crataegus tomentosa, Saltillo. (3337)

Cytospora hyalosperma Fr.

On Acer negundo., Saltillo. (3008)
Phlyctaena arcuata Berk.

On Datura stramonium, Lincoln. (3014)
* Septoria verbenae Rob.

On Verbena bracteosa, Cushman. (4040)
Melanconium magnum (Grev.) Berk.

On Hicoriasp., Saltillo. (3011)
Trimmatostroma americana Thuem.

On Acer negundo, Saltillo. (38012)
Pestalozzia monorhincha Sace.

On Gileditsia triacanthos, Saltillo. (3007)
Pestalozzia pezizoides DeNot.

On Vitis riparia, Saltillo. (3003)

11

Monilia penicillata HE. & FE.

On rotton pine wood, Kennedy. (83334)

Botrytis (Polyactis) doryphora Pound & Clements, n.sp.

Mycelium white, cobwebby, at length more. compact and
darker; filaments greatly elongated, nearly erect, septate,
sparely branched above; branches arising at right angles
to filament, short, strict, with a large terminal hastate
enlargement also found on short lateral branches; coridia
elliptical, white, in dense capitula, 5x24 p.

On leaves and stems of Pelargonium, Lincoln. (2498)

Arthobotrys superba oligospora (Fres.) Coemans.
On Pleurotus ostreatus, Lincoln. (3010)
Trichothecium obovatum (Berk.) Sace.
' On Cucurbitaria morbosa, Saltillo. (3002)
Diplocladium penicillioides Sace.

On decaying fungi, Lincoln. (3339)
Heterosporium didymosporum Clements, n.sp.

Effuse, dark green; hyphae very long, flexuose, sparingly
branched, fuscous, septate, 200x6 pv, conidia oblong-cylin-
‘drical or obovate, rounded at both ends, rarely aculeate,
olivaceous, 1, rarely 2—-3-septate, strongly constricted at
the septum, 20-25x10-12 yp,

On decaying osage orange, Lincoln. (3335)

=

Helminthosporium macrocarpum caudatum B. & Br.

On dead limbs, Saltillo. (8005)

Tubercularia pircuniae Speg.

On Hickory bark, Saltillo. (4201)

Hymenula fruticola Pound & Clements n.sp.

Sporodochia superficial, ellipsoid or oblong, often confluent,
pale reddish, farinose gelatinous, disposed in lines on the
angles of the capsules; sporophore simple, rarely furcate,
short, 30—45x4 4; spores ellipsoid or ovoid, spherical, hya-
line, 6-8x5-6 p.

On fruits of Salix longifolia, Stevens Creek. (4202)

12

Fusarium luteum Clements, n.sp.

Innate or erumpent, hard, convex or plane, golden yellow
hyphae short, simple, continuous; conidia falcate, curved,
acute at both ends, always 3-septate, hyaline, 32-39x4—5 p.

In decaying wood, Lincoln. (4203)

Fusarium rhizogenum Pound & Clements, n.sp.

Mycelium superficial, 1-2 mm. in diameter, dense, conver,
white, then yellow; filaments densly aggregated, ascend-
ing, septate, sparingly branched; conidia at the ends of
the branches, oblong, rounded at the ends, hyaline, 1-sep-
tate, T0x4 p.

On roots of seedling apple, Lincoln. (3013)

Phlyctospora sclerodermoides Clements, n.sp.

Subterranean, depressed globose, nearly smooth, brown; peri-
dium thick, coriaceous, radicate, gleba firm, chestnut
colored ; spores crowded, globose, brown, covered with more
or less reticulate papilla which are 24-34 » long, involved
in an indefinite hyaline mucuous, 18—25 y in diameter.

Peridium 34 cm. wide by 24 cm. high. In cultivated soil,
Lincoln. (4204)

Lepiota spectabilis Clements, n.sp.

Solitary; pileus carnose, membranaceous, densely covered
with silky fibrillae, or pulverulent, dilutely sulphur colored,
radiately striate or sulcate toward the margin, disc de-
pressed, smooth, yellow, 5 mm. in diameter; stipe slen-
der, strongly incrassate at the base, furnished above with
an annulus with minute scales, glabrous below, concolo-
rous; annulus straw colored, inferior, fixed; lamellae
crowded, narrow, dilutely yellow, remote; spores ovoid
5-6 » diameter, 1—-guttate.

Pileus 2-24 em.; stipe 3-4 cm. long, 3 mm. wide above,
7-8 mm. below. In greenhouse, Lincoln. (3227)

Agaricus haemorrhoidarius Kalch.

On ground, Lincoln. (3228)

13

Flammula alnicola Fr.
On stumps, Lincoln. (4207)
Galera striatula Clements, n.sp.

Pileus membranaceous, campanulate, convex, silky atomace-
ous, soot brown, strongly striate to the umbo, umbo
smooth, glabrous, brown; stipe elongate, equal, white, then
rufescent, glabrous; lamellae free, remote, affixed to a
collar, narrow, ochraceous rubiginous; spores ellipsoid,
eguttulate, 12-15x 7-8 p.

Pileus 14-2 cm.; stipe 9-10 cm. by 2 mm.

On moist ground, Lincoln. (8322)

Psilocybe gillettii Karst.

Franklin. (3159)

Collybia loripes Fr.
Franklin. (3258)

Psathyrella sulcata Clements, n.sp.

Pileus campanulate, at length convex expanded, gray, verg-
ing into black, pellucid, deeply radiately sulcate, umbo
smooth, yellow; stipe smooth, shining, semi-pellucid, slen-
der, fistulose, white above, rufescent below; lamellae
adnexed, slightly ventricose, cinereous, edge black, at
length everywhere brownish black; spores ovate, apiculate
at one end, fuscous, or brownish purple, 8-10x5-6 yp
Pileus 1-24 cm.; stipe 4-6 cm. x 1-2 om.

On ground, Lincoln. (4208)

Coprinus atramentarius (Bull.) Fr.
On ground, Kennedy. (4211)
Coprinus picaceus (Bull.) Fr.

On ground, Hastings. (4206)
Coprinus velox Godey.

On ground, Lincoln. (4209)

Polyporus varius Fr.
On wood, Lincoln. (4210)

14

Poria contigua Fr.
On dead limbs, Lincoln. (3344)
Craterellus sinuosus crispus (Fr.) Massee.
Lincoln. (3343)
Corticium lacteum Fr.
On bark, Lincoln. (3355)

Corticium pellicula Karst.
On bark, Lincoln. (3346)
Corticiuwm roseolum Massee.
On wood, Lincoln. (4198)
Coniophora wmbrina (A, & 8.) Fr.
On bark, Lincoln, (3342)
Nitella translucens (Pers.) Ag.
York. (3370)
Nitella translucens form confervoides Thuill.
York. (3369)
Chara crassicaulis Schleich.
Haigler (3366, 3367), Pine Ridge. (3368)
Chara evoluta Allen.
Sheridan county, part of material reported as C. foetida
longibracteata in 1892 Report. (2654)
Chara sejuncta A. Br.
Minden. (3365)
Pottia truncata Fuern.
Saltillo. (3364)
Hypnum aduncum Hedw.
Decatur. (3351)
Dryopteris cristata (L.) Gray.
South Dismal River, Hooker Co, (4101)
Potamogeton heterophyllus Schreb.
Kennedy. (4101)
Potamogeton interruptus Kit.
Thedford. (4102)

15

Potamogeton perfoliatus richardsonii Arn.
Bennet Lake, Grant county. (4103)
Potamogeton pusillus L.
Thedford. (4104)
Naias guadalupensis (Spreng. ) Morong.
Whitman. (4105)
Sagittaria arifolia J. G. Smith in lit.
Hooker county. (4106)
Paspalum setaceum ciliatifolium (Michx) Vasey.
Mullen. (4107)
Panicum dichotomum villosum Vasey.
Plum Creek. (2913)
Sporobulus filiformis (Thurber) Rydberg. 8. depauperalus
filiformis Thurber, S. gracillimus Scribner.
Thedford. (4108)
Poa fendleriana (Steudel) Vasey.
Thedford. (4109)
Scolochloa festucacea ( Willd.) Lk.
Whitman. (4110)
Agropyrum caninum unilaterale (Cassidy) Vasey.
Grant county. (4114)
Hordeum pusillum Nutt.
Thedford. (4114) Some of the Nebraska specimens named
H. nodosum belong here—perhaps all. (Rydberg).
Elymus macounti Vasey.
Grant county. (4113)
Cyperus houghtonit Torr.
Natick. (4115)
Carex beckit Boott.
Long Pine. (4132)
Carex filiformis lanuginosa (Michx.) B.S. P.
Thedford. (4116)
Carex limosa L.
Kennedy. (4133)

16

Carex pseudocyperus americana Hochst.
Grant county. (4120)
Carex scoparia Schkur.
Thedford. (4117)
Scirpus lacustris occidentalis Watson. .
Thomas and Hooker counties.~ (4121)
Lemna gibba L.
Plummer Ford, Thomas county. (4130)
Lemna perpusilla Torr.
Plummer Ford, Thomas county. (4119)
Heteranthera dubia, (Jacq.) Morong.
Kearney. (4998)
Juncus alpinus insignis, Fries.
Pishelville. (2247)
Leptorchis loesilit (L.) MacM.
Thedford. (4134)
Salix cordata angustifolia (Pursh) Anders.
Thomas and Hooker counties. (4118)
Boehmeria cylindrica (L.) Willd.
Halsey (4122), Fremont (3348), Pishelville (2768), Endi-
cott, (2169)
Polygonum litorale Lk.
Mullen. (4136)
Polygonum punctatum leptostachyum (Meisn.) Small.
Thomas, Hooker, and Grant counties. (4136)
Chenopodium rubrum L.
Grant county. (4129)
Salsola kali tragus Oeder.
Aten (2646), Republican City. (2102) All localities
heretofore given for S. kali should be transferred to the

var. tragus. All material in the Survey Herbarium is to
be referred to the variety.

17

Acnida tamariscina (Nutt.) Gray.

- Thomas county. 4138. This has been confounded with A.
tuberculata Moq. which is common in eastern Nebraska.
(Rydberg. )

Talinum calycinum Engelm.

Specimens collected in Nebraska, probably at Fort Robinson,
by Dr. Wilcox are in the National Herbarium at Wash-
ington. (Rydberg. )

Arenaria michauxti Hook.f.

Franklin. (2089)

Ranunculus multifidus terrestris Gray.

Fremont. (3349)

Ranunculus septentrionalis Poir.

Emerson. (2510)

Sanguinaria canadensis L.
Bellevue. (3116)
Cardamine hirsuta L.
Grand Rapids. (2851)
Lepidium draba L.
Wymore. (3393) Introduced.
Crataegus coccinea L.
Forks of Dismal River, Hooker county. (4128)
Crataegus coccinea macracantha Dudley.
Grand Rapids. (2850)
Geum japonicum Thurber.
Natick. (4123)
Amorpha nana Nutt.
Aten. (2653)
Psoralea cuspidata Pursh.

Grand Rapids. (2946)

Euphorbia heterophylla graminifolia (Michx.) Engelm,

Carns. (27104)

Euphorbia serpens H. B. K.
Lincoln. (3375) ;

18

Hypericum sphaerocarpum Michx.

Richardson county, July 22,1573. In the Aughey Collec-
tion in the herbarium of the University, labeled Lysima-
chia stricta. (Rydberg. )

Didiplis linearis Raf.

Lincoln. (4139)

Ludwigia alternifolia L.
Endicott, (2047)
Stenosiphon virgatus Spach.
Franklin. (2052)
Hippurus vulgaris L.
Whitman. (4124)
Myriophyllum spicatum L.
Grant county. (4131)
Aralia nudicaulis L.
Shaded bluffs of the Missouri throughout northeastern Ne-
braska. (2548)
Sium cicutifolium Gmelin.
Grant county. (4127)
Foeniculum officinale L.
Pishelville. (2754)
Gentiana andrewsit Griseb.
Mullen (4126), Fremont (3350), Minden.
Asclepias jameswi Torr.
Haigler. (2057)
Cuscuta coryli Eng.
On Salix sp., and Aster sp., Hooker county (4125), on
Salix longifolia, Chelsea. (2808)
Gilia inconspicua Doug].
Wabash. (3358)
Lithospermum arvense L.
Lincoln, (4095)

Verbena hastata x stricta Rydberg. (V. paniculata x stricta
Engelm?) Hooker county. (4132)

19

Agastache scrophularifolia (Willd.) OK. !
Bellevue. (3128)
Koellia lancelata (Pursh) OK.
Valleys of Middle Loup and South Dismal. (4133)
Pedicularis lanceolata Michx.
Bellevue. (3123)
' Datura tatula L.
Thedford, escaped. (4140)
Lobelia spicata hirtella Gray.

Thedford (4134). Perhaps the majority of specimens of
L. spicata reported from the state belong to this variety.
(Rydberg).
Aster junceus Ait?
Thedford. (4139)
Aster oblongifolius rigidulus Gray.
Long Pine Canon. (2941)
’ Aster umbellatus pubens Gray.
Halsey. (4135)
Helianthus petiolaris patens (Lehm).
Grant county. (4139)
Helianthus strumosus L.
Long Pine. (2895)
Coreopsis involucrata Nutt.
Endicott. (2080)
Bidens connata comosa Gray,
Lomo. (28944)
Gaillardia aristata Pursh.
Franklin. (2078)
Polypteris hookeriana Gray.
Haigler. (2064)

20

SUMMARY.

Number of species reported in Webber’s Catalogue (1889) . 1890
Additions in Webber’s appendix to his catalogue, (March

LOE) wate yecd one oe NOSE Ngee gawe eee UR Oey _. 482

Additions in Dr. Bessey’s supplement to Webber’s Appendix
(Jane 1892)... cers are onenw argc sire vanes oe res 170 —

Additions in Report of the Survey for 1892 (1893)... 159
Less new hosts only ....... +--+ esse cree eee 13

—— 146
Additions in this Report... ...-......e 0 cee eee eee 197.
Less new hosts only......... 0022-2000: we wii 15

—— 182

Total number of species reported for the state...... 2820

.

A Revision oF THE NOMENCLATURE OF THE NEBRASKA
PoOLYPETALAE.
BY P. A. RYDBERG.*

Herewith I submit an attempt at a revision of the nomen-
clature of the reported Polypetalae of Nebraska, I say an at-
tempt, as I know full well that the list is not perfect. Owing to
the fact that my time has been limited and that the otherwise
very good botanical library of the University lacks some of the
older foreign works in which original descriptions of certain of
our plants are to be found, I have not been able to do the work
as I had wished. The original description of a species is espe-
cially necessary in this work, as American botanists have been in
the habit of citing nomina nuda in the same manner in which
they citenames accompanied by descriptions. Professor Greene’s
reprint of Fraser’s catalogue has saved me from doing as Pro-
fessor MacMillan has done in a number of cases in his Metasper-
mae of the Minnesota valley, namely, accepting nomina nuda,

*Read before the Seminar, February 17, 1894.

21

T have tried to follow as rigidly as possible the Paris Code, the
Rochester Rules of the Botanical Club of the A. A. A. S., and
the amendments male thereto at the Madison meeting, although
I wish to record my strongest protest against one of the latter, as
it introduces some most inelegant nomenclature. In work of this
kind the one indispensible book is, of course, Dr. Kuntze’s
Revisio Generum Plantarum. This book, also, has caused the
most changes in (or rather restorations of) generic names.
Many corrections of the nomenclature of generic names have
been made from the writings of Professor Greene and Dr. Brit-
ton; one (Leptoglottis for Schrankia) I have made myself.
The sources from which I have derived corrections of specific
names are too diverse to be mentioned here. The two books
most often referred to and from which, perhaps, I have had the.
most help are Watson’s Index and MacMillan’s Metaspermae.
At the same time I have found Professor Greene correct in stat-
ing that the former is not exact, and that the latter will be useful
to “those who know how to use ”’ it.

Asa basis I have taken the sixth edition of Gray’s Manual,
as it is most commonly used and-latest published manual, and
have changed those names which do not conform to recent views.
Those not changed may be regarded as in accordance with them
except as to the citation of authors. In the case of our western
species not given in Gray’s Manual, the corrections are made
from Coulter’s Manual of the Rocky Mountain Region. In cases
where the two books disagree and no correction is made, the
name in Gray’s Manual should be regarded as the correct one.
Thus, Coulter has Anemone decapetala* and the genus Vesicaria.
Gray has Anemone caroliniana and Lesquerella. The latter
two should be used.

My list contains 130 names, which is about thirty per cent
of the reported Polypetalae of the state. Not all of these
changes, however, are due to the requirements of correct nomen-

*The true A. decapetala may be found in the southern part of the Rocky Mountain region,
but not in Nebraska. Coulter’s A. decapetala may include both, ©

22

clature, several being required by different limitation of genera
or species. It is quite likely also that some necessary changes
have been overlooked, and, on the other hand, that som2 changes
may not stand.

The first name given is the corrected name, the last one the
name used in the manuals. In many cases I have found it nec-
essary to interpolate either the binomial under which the plant
was first described or such synonyms as will show the derivation
of the several names.

Pulsatilla hirsutissima (Pursh) Britton. Contrib. Herb. Colum-
bia Coll. 23,217 (1891), first published as Clematis hirsutis-
sima Pursh. Fl. Am. Sept..385. (1814)
Anemone patens var. nuttalliana Gray Man. Ed. 5 36. (1867)
Dr. Britton as well as the best European authorities, con-
sider Pulsatilla a genus distinct from Anemone.
Anemone quinquefolia L. Spee. Pl. 541. (1753)
Anemone nemorosa American authors, not Linne.
Anemone canadensis L. Syst. Ed. 12, IIL, app. 231. (1768)
Anemone pennsylvanica L. Mant. II. 247. (1771)
Syndesmon thalictroides (L.) Hoffmansg. Flora XV., part IL,
Intell. Bl. No. IV., 34. (1832)
Anemone thalictroides L. Spec. Pl. 542. (1758)
Anemonella thalictroides Spach. Hist. Veg. VIL. 240. (1839)
This plant has been referred to Thalictrum as well as to
Anemone. It is generally regarded as the type of a dis-
tinct genus, and should have the older generic name—Syn-
desmon.
Ranunculus lacustris Beck & Tracy, Eaton’s Man. Ed. 3,423.
(1822)
Ranunculus multifidus Pursh. Fl. Am. Sept. 736 (1814),
which name is preoceupied by R. multifidus Forskal F.
Egypt, 102. (1755) :
Ranunculus lacustris terrestris (Gray) Mac M., Met., Minn.
Valley 247. (1892)

23

Ranunculus multifidus terrestris Gray Man. Ed. 5,41. (1867)
Ranunculus ovalis Raf. Journ. Bot., 268. (1814)
Ranunculus rhomboideus Goldie Kdinb. Phil. Journ. VI., 329.

(1822)

Ranunculus macountt Britton Contrib. Herb. Columbia Coll. No.

30, 38. (1892) 2

Ranunculus hispidus Hook. Fl. Bor. Am. I., 19. (1830), not

R. hispidus, Michx. Fl. N. Am. I., 321. (1803)

Ranunculus ranunculinus (Nutt. )
Cyrtorrhynca ranunculina Nutt. in Torry & Gray’s Fl. N. Am.

I, 26. (1838)

Ranunculus nuttallii Gray, Proc. Acad. Phil., 56. (1863)
Delphinium carolinianum Walt. Fl. Car., 155. (1788)

Delphinium azureum Michx. Fl. N. Am. L, 314. (1803)
Delphinium urceolatum Jacq. Icon. Pl. Par, I, 101. (1871),

and Collect. L, 153. (1786)

Delphinium exaltatum Ait. Hort. Kew. IL, 244. (1789)
Leontice thalictroides L. Spec. Pl., 312. (1753)
Caulophyllum thalictroides Michx. Fl. N. Am. 1, 205. (1803)

Recent authors are of the opinion that our species is not
different enough from the other species of Leontice to
warrant the establishment of a separate genus.

Castalia tuberosa (Paine) Greene Bull, Torr. Bot. Club XV., 84.
(1888)
Nymphaea tuberosa Paine Cat. Pl. Oneida, 184. (1864)
Nymphaea reniformis DC. Syst. II., 55 (1821), not N. reni-
formis Walt. Fl. Car. 155. (1788)

The genus Castulia was separated from Nymphaea by Salis-
bury in 1805. Ignoring this, Smith in 1808 made the
genus Nuphar, including therein the species left in Nym-
phaea by Salisbury, and used the latter name for those
species for which Salisbury founded Castalia. The next
change must follow:

24

Nymphaea advena Solander in Ait. Hort. Kew. II., 226. (1789)
Nuphar advena Ait. f. Hort. Kew. IIT., 295. (1811)
Neckeria aurea (Michx.) Pfeiffer Bot. Zeit. XV., 649. (1857)
Corydalis aurea Willd. Enum. 740. (1809)
The genus Neckeria was established by Scopoli in 1777,
Corydalis by DeCandolle in 1805.

Neckeria aurea occidentalis (Gray. )

Corydalis aurea occidentalis Gray Pl. Fend.6. (1849)

Neckeria micrantha (Engelm.) MacM. Met. Minn. Vall. 255.
(1892)

Corydalis aurea micrantha Engelm. in Gray Man. Ed. 5, 62,
(1868
Corydalis 7 Gray Man. Ed. 6, 61. (1889)

Neckeria curvisiliqua (Gray).

Corydalis aurea curvisiliqua Gray, Proc. Am. Phil. 57. (1863)
Corydalis curvisiliqua Engelm. Gray Man. Ed. 5, 62. (1868)
Bicuculla cucullaria (1. )
Fumaria cucullaria L. Spec Pl. 699. (1753)
Dicentra*cucullaria DC. Syst. I., 108. (1818)
Bicuculla Adans. was published in 1763, Dicentra Bernh. in
: 1833.

~Biculla canadensis (Goldie).

Corydalis canadensis Goldie Edin. Phil. Journ.V., 330. (1822)
Dicentra canadensis DO. 1.c.

Lepidium incisum Roth Nov. Cat. I., 224 (1797-1806), not L.
imcisum Mv. Riebst. Fl. T. & C. IL, 98 (1808), is, ac-
cording to Dr. Kuntze, Rev. Gen. Pl. L., 35, the same as

Lepidium intermedium Gray Pl. Wright, IL, 15. (1852)

Bursa bursa-pastoris (L.)

Thlaspi bursa-pastoris L. Spec. Pl. 647. (1753)
Capsella bursa-pastoris Moench. Meth. 271.

This isa good illustration of whata strict following of the rules
of the Botanical Club of theA. A. A. 8, will lead to. Bursa-
pastoris is the oldest specific name. It is agreed gener-
ally that the species should not be included in the genus

25

Thlaspi, and the oldest generic name after 1753 is Bursa,
used by Wiggers in 1780. Capsella Med. appeared first
in 1792. Bursa must therefore be the generic name, and
bursa-pastoris the specific name. The amendment to the
Rochester rules made at Madison in striking out a part of
§ ITI. was, in my opinion, not a wise one. The nomencla-
ture which results is often, to say the least, inelegant and
uncouth. Apios apiosand Phragmites phragmites are in
plain English. comparable to “dog dog’’ or “cat cat.”
Bursa bursa-pastoris translated is ‘‘Shepherd’s purse
purse.”

Lesquerella argentea (Pursh) MacM. Met. Minn. Vall. 263.

(1892)

Myagrum argenteum Pursh Pl. Am. 434. (1814)

Alyssum ludovicianum Nutt. Gen. IT., 63. (1818)

Lesquerella ludoviciana Wats. Proc. Am. Acad. A. S. XXIII,
254. (1888)

Coulterina didymocarpa ‘Hook.) OK. Rev. Gen. I, 481. (1891)
Vesicaria didymocarpa Hook. FI. Bor. Am. IL, 48. (1833)
Physaria didymocarpa Gray, Gen. I., 162. (1848)

The name Physaria cannot be used as there is a genus Phys-
arium Persoon (1795) among the fungi which is far
older.

Roripa nasturtium (L.) Rusby Mem. Torr. Bot. Club IIL, no 3,

5. (1893)
Sisymbrium nasturtium L. Spec. Pl. IL, 657. (1753)
Nasturtium officinale R. Br. Hort. Kew. Ed. 2, IV., 110.
(1812)

Roripa Scopoli was published in 1760; Nasturtium Robert
Brown in 1812.

Roripa palustris (L.) Greene Man. Bay Reg. Bot. 21. (1894)

Sisymbrium palustre L. Spec. Pl. 657. (1753)

Nasturtium palustre DC. Syst. IL, 191. (1821)

26

Roripa palustris hispida (Desv. )
Brachylobus hispidus Desv. Journ. TIT., 183. (1814)
Nasturtium palustre hispidum Fisch. & Mey. Ind. Sem.
Petr. IIL.,41. (1838)

Roripa obtusa (Nutt. )

Nasturtium obtusum Nutt. T. & Gr. Fl. L., 74. (1838)
Roripa sessiliflora (Nutt.)

Nasturtium sessiliflorum Nutt. T. & Gr. FLL, 73. (1838)
Roripa curvisiliqua (Nutt. )

Nasturtium curvisiliqua Nutt. Le.

Roripa sinuata (Nutt. )
Nasturtium sinuatum Nutt. 1c.

Roripa armoracia, (L.)
Cochlearia armoracia L. Spee. Pl. 648. (17538)
Nasturtium armoracia Fries Fl. Scand. (18385)

Sisymbrium pinnatum (Walt.) Greene Bull. Cal. Acad. IT.
(1887)
Erysimum pinnatum Walt. Fl. Car. 174. (1788)
Sisymbrium canescens Nutt. Gen. II., 71. (1818)

Stanleya pinnata (Pursh. )
Cleoma pinnata Pursh Fl. Am. 739. (1814)
Stanleya pinnatifida Nutt. Gen. II, 71. (1818)

Arabis brachycarpa (Torr. & Gr.)
Turritis brachycarpa Torr. & Gr. Fl. L, 79. (1838)
Arabis drummondii Gray Man. Ed. 5, 69. (1868) not Graham.
Arabis confinis Wats. Proc. Am. Acad. A. & S. XXIL,.466.

(1887)

Arabis glabra (L.) Weinman Cat. Dorp. 18. (1810) -
Turritis glabra L. Spec. Pl. 666. (1753)
Arabis perfoliata Lam. Dict. I, 219.

Cardamine laciniata (Muhl.) Wood Bot. and Flor. 38. (1861)
Dentaria laciniata Muhl. in Willd. Sp. Pl. IIL, 479. (1800)

Dentaria is included in Cardamine by the best authorities.

27

Jacksonia trifoliata Raf. Med. Rep. 352. (1808)
Cleome dodecandra Michx. Fl. Am. IL. 32. (1803) not Linne.
Polanisia graveolens Raf. Journ. Phys. 98. (1819)
Jacksonia trachysperma (Torr. & Gr.) Greene Pittonia IL, 175.
(1891)
Polanisia trachysperma Torr. & Gr. Fl. I., 122. (1838)
C'eome serrulata Pursh. Fl. Am. 441. (1814)
Cleome integrifolia T. & G. Fl. 1, 122. (1838)
Helianthemum majus (L.) B. 8, P. Cat, N. Y. (1888)
Lechea major L. Spec. Pl. 90. (1753)
Helianthemum canadense Michx. Fl. Am. Bor. 1., 308. (1803)
Viola palmata obliqua (Hill) Hitchcock Fl. Ames 487. (1891)
Viola obliqua Hill Hort. Kew. 316. (1768)
Viola cucullata Ait. Hort. Kew. IIL, 288. (1789)
Viola palmata cucullata Gray Bot. Gaz. XI., 254. (1386)
Agrostemma githago L. Spec. Pl. 433. (1753)
Lychnis githago Lam. Encyc. IIT, 643.
This is now generally held distinct from Lychnis,
Arenaria franklinii hookeri (Nutt. )
Arenaria hookeri Nutt. in T. & Gr. Fl. 1, 178. (1838)
Arenaria franklinti minor Hook. & Arn. Bot. Beachy, 326.
(1841)
Anychia canadensis (L.) B. 8. P. Cat., N. ¥. (1858)
Queria canadensis L. Spec. Pl., 90. (1753)
Queria capillacea Nutt. Gen. I., 159. (1818)
Anychia capillacea DC. Prodr. IIL, 369. (1828)
Elodes virginica (L.) Nutt. Gen. IL, 17. (1818)
Hypericum virginicum L. Spec. Pl. Ed. 2, 1104. (1761)
Hypericum campanulatum Walt. Fl. Car., 191. (1788)
Elodes campanulata Pursh Fl., 879. (1814)
Hibiscus laevis Scop. Del. Flor. TIL, 35. (1788)
Hibiscus militaris Cav. Diss., 352. (1790)
Abutilon abutilon (1. )
Sida abutilon L. Spec. Pl., 685: (1753)
Abutilon avicennae Gaertn. Fr. IT, 251. (1800)

28

Malveopsis coccinea (Nutt.) OK. Rev. Gen., 72. (1891)
Malva coccinea Nutt. Fraser’s Cat. (1813)
Malwastrum coccineum Gray Pl. Fend., 21. (1849)
Malveopsis Presl. was published in 1844; Malvastrum Gray
in 1849.
Impatiens biflora Walt. Fl. Car., 219. (1788)
Impatiens fulva Nutt. Gen. I., 146. (1818)
Parthenocissus quinquefolia (L.) Planchon Monogr. Ampelid.
L, 488. (1887)
Hedera quinquefolia L. Spec. Pl., 292. (1753)
Ampelopsis quinquefolia Michx. Fl. I., 160. (1803)
According to Planchon the name Ampelopsis belongs to the
genus Cissus of Gray’s Manuel Ed. 6. No true Cissus
Linne is found in the region of the manual.
- Vitis americana Marsh.
Vitis vinifera americana Marsh. Arb. 166. (1785)
Vitis aestivalis Michx. Fl. IT, 230. (1803)
_ Acer saccharinum L. Spec. Pl. 1055. (1753)
Acer dasycarpum Ebrh. Beitr. TV., 24.
The sugar maple, A. Saccharinwm Wang., which does not
grow in Nebraska, becomes A. saccharum Marsh:
Acer negundo IL. Spee. Pl. 266. (1753)
' Negundo aceroides Moench. Meth. 334.
_ Rhus radicans L. Spec. Pl. 266. (1753)
hus toxicodendron L. Spec. Pl. 1 ¢.
Both are published on the same page, but R. radicans first.
Rhus trilobata Nutt. in Torr. & Gr. Fl. N. A. LT, 219. (1838)
Rhus canadensis trilobata Gray Man. Ed. 6, 119. (1889)
This is a good species.
Lotus americanus (Nutt.) Bisch. Hort. Heid, (1839)
Trigonella americana Nutt. Gen. IL, 120. (1818)
Hosackia purshiana Benth. in Bot. Reg. 1257.
This must be included in the genus Lotus. The. oldest
name is Lotus sericeus Pursh (1814), which, however, is
preoccupied by Lotus sericeus DC. Cat. Mons. (1818)

29

Medicago arabica (L.)
Medicago polymorpha e. arabica L. Spec. Pl. 280. (1753)
Medicago maculata Willd. Sp. Pl. 1412. (1800)
As the plant is nota native of Arabia, Willdenow thought
the name inappropriate. Hence the change.

Psoralea digitata Nutt. Torr. & Gray Fl. N. A. TL, 300. (1838)
Psoralea campestris Nutt. 1. ¢.
The latter is only a form of the former, and scarcely de-
served a varietal name.
Amorpha nana Nutt. Fraser’s Cat. (1813)
Amorpha microphylla Pursh Fl 466. (1814)

There has been an idea generally prevailing that the A.
nana of Fraser’s Catalogue and that of Nuttall’s Genera
are not the same. The causes of this idea seem to have
been that Dr. Gray found in Lambert’s Herbarium under
this name a variety of A. fruticosa (var. angustifolia
Pursh), and that the same variety has been cultivated in
England and figured in the botanical magazines under
this name. Mr. Fraser was a nurseryman, not a botanist,
and Fraser’s Catalogue is known to have been prepared
by Nuttall. It may be that Fraser had both A. nana
and A. fruticosa angustifolia in the nursery and a mis.
take of labels was made or a mistake might even have
been made when the plants were shipped from America to
England. It is evident enough that the A. nana of Fra-
ser’s Catalogue and that of Nuttall’s Genera are the same;
first, because the descriptions agree perfectly; second, be-
cause A. nana in Fraser’s catalogue is said to be “col-
lected near the Mandan towns 1,600 miles up thé Mis-
souri,” which is, as far as I know, far outside of the range
of A. fruticosa angustifolia, but about the center of that of
A. microphylla Pursh,; third, because Nuttall in his Gen-
era expressly says ‘A. nana T. N. (Thomas Nuttall) in
Fraser’s Catal. 1813,” and also says that it is the same as

30

A. microphylla Pursh II., 466. Which should be re-
garded as the strongest evidence—specimens found in a
foreign herbarium and plants sent out from a foreign nurs-
ery on the one hand, or on the other the author’s own
words in print, strenghthened by those of Pursh, who states
that his A. microphylla is the same as A. nana of Fraser’s
Catalogue? The A. nana of Fraser's nursery may be
whatever it please.
Dalea dalea (.) Mac M. Torr. Bull. XTX. (1892)
Psoralea dalea L. Spee. Pl,, 764. (1753)
Dalea alepecuroides Willd. Spec. Pl. IIL, 1336. (1803)
Dalea eneneandra Nutt. Fraser’s Cat. (1813)
Dalea laxiflora Pursh Fl. 741. (1814)
Kuhniastera compacta (Spreng.) OK. Rev. Gen., 192. (1891)
Dalea compacta Spreng. Syst., 327. (1826)
Petalostemon macrostachyus Torr. Ann. Lye., N. Y., 176.

(1828)
Kuhniastera Lam. was founded in 1789, Petalostemon Michx.
in 1808.
Kuhniastera purpurea (Vent.) Mac M. Met. Minn, Vall., 329.
(1892)

Dalea purpurea Vent. Hort. Cels., 40. (1800)
Petalostemon violaceus Michx. Fl. IL, 50. (1803)
Kuhniastera candida (Michx.) OK. Rev. Gen. 192. (1891)
Petalostemon candidus Michx. F\. II., 49. (1803)
Kuhniastera multiflora (Nutt.) OK. Le
ee ad multiflorus Nutt. in Journ. Acad. Philad. VIL,
Kuhniastera villosa (Nutt.) OK. Le.
Petalostemon villosus Nutt. Gen. ITI., 85. (1818)
Astragalus ceramicus Sheldon Minn. Bot. Stud. No. 9, 19.
(189+)
Phaca picta Gray Pl. Fend. 37, (1849)
Astragalus pictus Gray Proc. Am. Acad. VI., 214: (1866),
not A, pictus Steud. (1840), nor A. pictus Boiss (1853)-

31

Astragalus ceramicus longifolius (Pursh)
Psoralea longifolia Pursh Fl. Am. Sept. IL, 741. (1814),
not A. longifolius Lam. Enc. Meth. I., 322. (1783)

The name longifolius, which is the first specific name, can
not be used as a specific name in the genus Astragalus,
but may well be used as a varietal name under A. cerami-
cus. In fact it is the only one to be permitted. Mr.
Sheldon in naming the varieties A. ceramicus jonesii and
A, ceramicus imperfectus violated articles 57 and 58 of
the Paris Code.

Astragalus carolinianus L. Spec. Pl. 757. (1753)
Astragalus canadensis L. l.c., but lower on the page.

Astragalus crassicarpus Nutt. Fraser’s Cat. (1813)
Astragalus caryocarpus Ker. Bot. Reg. IL, 174. (1816)

Astragalus viridis (Nutt. )
Kentrophyta montana Nutt. Torr. & Gray Fl. I., 353. (1838),

not A. montanus L.
Kentrophyta viridis Nutt. le.
Astragalus kentrophyta Gray Proc. Am. Phil., 60. (1863)
Astragalus gilviflorus Sheldon Minn. Bot. Stud. No. 9, 21.
(1894)
Astragalus triphyllus Pursh Fl Am, Sept. IL, 740 (1814),
not A. triphyllus Pallas Astr., 68. (1800)
This species has received two other names, but neither can
be used in the genus Astragalus.
Astragalus spatulatus Sheldon Minn. Bot. Stud. No. 9, 22.
(1894)
Homalobus caespitosus Nutt. in Torr. & Gray Fl. N. A. 1., 352.
(1838)
Astragalus caespitosus Gray Proc. Am. Acad. VI., 230 (1864)
not A. caespitosus Pallas Astr. 70. (1800)
This species has received two other names, both preoccupied.
Spiesia lambertit Pursh OK. Rey. Gen. I., 207. (1891)
Oxytropis lambertii Pursh Fl. 740. (1814)
Spiesia Necker was founded in 1790, Oxytropis DC. in 1802

32

Spiesia lambertii sericea (Nutt. )
Oxytropis sericea Nutt. Torr. & Gray Fl. 1, 339. (1838)
Oxytropis lambertii sericea Gray Coult. Man. 71. (1885)
Spiesia multiceps (Nutt.) OK. Le.
Oxytropis mulliceps Nutt. Torr. & Gray Fl. I., 341. (1838)
Spiesia inflata (Hook. )
Oxytropis arctica inflata Hook. Fl. Bor. Am. I, 146. (1833)
Oxytropis podocarpa Gray Proc. Am. Acad. VI., 234. (1863)
Meibomia canadensis (L.) OK. Rev. Gen. L, 195. (1891)
Hedysarum canadense L. Spec. Pl., 749. (1753)
Desmodium canadense DC. Prodr. I1., 328, (1825)
Meibomia was used by Fabricius in 1763, Desmodium Desv,
was established in 1813.
Meibomia canescens (L.) OK. lc.
Hedysarum canescens L. Spec. Pl. 748. (1753)
Desmodium canescens DO. Prodr. II., 8328. (1825)
Meibomia grandiflora (Walt.) OK. l.c., 196.
Hedysarum grandiflorum Walt. Fl. Car., 185. (1788)
Hedysarum acuminatum Michx. Fl. IL,72. (1803)
Desmodium acuminatum DC, Prodr. IL, 329. (1825)
Meibomia dillenit (Darlingt ) OK. l.c., 195.
Desmodium dillenii Darlington Fl. Cestr. 414. (1837)
Meibomia rigida Ell. OK. Le., 198.
Hedysarum paniculatum L. Spec. Pl, 749. (1753)
Desmodium paniculatum DC. Prodr. II., 329. (1825).
Meibomia illinoensis (Gray) OK. Le.
Desmodium illinoense Gray Proc. Am. Acad. VIII, 289.
(1870) ‘
Lespedeza frutescens ( Willd.) Ell. Sk., 206. (1824)
Hedysarum frutescens Willd. Sp. Pl. IIL, 1193. (1802)
Lespedeza capitata Michx. Fl. Am. II., 71. (1803)
Lathyrus decaphyllus Pursh Fl. Am., 471. (1841)
Lathyrus polymorphus Nutt. Gen. IL, 96. (1818)

83

Faleata comosa (L.) OK. Rev. Gen. I, 182. (1891)

Glycine comosa L. Spec. Pl., 754. (1753)

Glycine monoica L. Spec. Pl. Ed. 2, 1023. (1761)

Amphicarpaea monoica Nutt. Gen, II., 113. (1818)

* Falcata Gmelin was established in 1791, Amphicarpa Ell.
in September, 1818. The latter was changed into Amphi-
carpaea by DeCandolle in 1825. The two latter names
are also antedated by Amphicarpum Raf. (January, 1818).
which is something else.

Falcata pitcheri (T. & Gr.) OK. Le. :

Amphicarpaea pitcheri T. & Gr. Fl. N. A., L, 292. (1838)

Apios apios (L.) McM. Bull. Torr. Bot. Club XIX. (1892)
- Glycine apios L. Spec. Pl. 753. (1753)

Apios tuberosa Moench Meth. 165. (1794)

Phaseolus polystachyus (L.) B.S. P. Cat. N.Y. (1888)

Dolichos polystachyus L. Spec. Pl. 726. (1753)

Phaseolus perennis Walt. Fl. Car. 182. (1788)

Gymnocladus dioicus (L.) Koch Dendr. 1,5. (1869)

-Guilandina dioica L. Spec. Pl. 381. (1753)

Gymnocladus canadensis Lam. Dict. I., 33. (1783)

Acuania tllinoensis (Michx.) OK. Rev. Gen. I., 158. (1891)

Mimosa illinoensis Michx. Fl. IL, 254. (1803)

Acacia brachyloba Willd. Sp. PL VI., 1071. (1805)

Desmanthus brachylobus Benth. Hook. Journ. Bot. VL, 358,

Leptoglottis intsia (Walt. )

Mimosa intsia Walt. Fl. Car. 252. (1788)

Schrankia uncinata Willd. Spec. Pl. IV., 1042. (1805)

Leptoglottis nuttullii DC. Mem. Leg. 451. (125)

The genus Schrankia of Willdenow (1805) is antedated by
Schrankia Med. Uster. N. Annal. I., 42, and used by Moench
in Meth. 263 (1794). As the name Schrankia cannot be
used, the only available generic name is Leptoglottis DC.,
although the generic characters given are not good.

34

Opulaster opulifolius (L.) OK. Rev. Gen. 949. (1891)
Spiraea opulifolia L. Spee. Pl. 489. (1753)
Physocarpus opulifolius Maxim.
Opulaster Med. was established on this species in 1799,
Physocarpus Camp. as a section of Spiraea in 1824. -

Rosa virginiana Miller Dict. (1768)
Rosa blanda Ait. Hort. Kew. IIL, 202. (1789)
Rosa virginiana arkansana (Porter) MacM. Met. Minn. Vall.
304. (1892).
Rosa arkansana Porter Fl. Col. 38. (1874)
Fragaria vesca americana Porter Bull. Torr. Bot. Club XVII,
15. (1890)
Fragaria vesca Auct. Am., not Linne.

The American variety differs somewhat from the European,
especially in its thinner and smoother leaves, but I do
not think sufficiently to justify a new species. Dr. Brit-
ton in Bull. Torr Bot. Club 1892, page 222, makes of it a
species and points out as a distinctive character that the
achenes are superficial, ‘which are scarcely or not at all
imbedded in the ovoid fruit.” But so they are in the
European F#. vesca. DeCandolle and other European bot-
anists use this very character to distinguish F. vesca from
F. elatior and F. virginiana.

Geum canadense Jacq. Hort. Vind. IL., 82. (1772)
Not Geum canadense Murr. Con. Goett. V., 34. (1790)
Geum album Gmelin Syst. IL, 861. (1791)
Potentilia gracilis chrysantha (Lehm. )
Potentilla chrysantha Lehm. Hook. Fl, Bor. Am. I., 193.
(1833), not P. chrysantha Trev., which is older,
Potentilla rigida Nutt. Journ. Acad. Philad. VIL, 20 (1833)

Not P. rigida Wall., which is older.

Potentilla gracilis rigida Wats. Rev. Potentilla 557.

If this is to be regarded as a variety of P. gracilis, which I
believe it should, the varietal name must be chrysantha.,

35

But if it should be raised to the rank of a species, its
name must be P. nuttallit Lehm Ind. Sem. h. Hand. Add.
12 (1852), as the other two are not available as specific
names.
Sanguisorba sanguisorba (L.)
Potcrium sanguisorba L. Spee. Pl. 904. (1753)

The two genera are now united, even by Dr. Gray. But he
chose the latter name. Sanguisorba is found on page 116
of the Species Plantarum, Polerium on page 994.

Agrimonia striata Michx. Fl. Am. 1, 287. (1803)
Ayrimonia eupatoria Auct. Am.
Dr. Britton in Bull. Torr. Bot. Club XVIII, 367 (1891)
has pointed out that our common Agrimonia is not the
A. eupatoria of Europe.

Pirus coronaria iowensis Wood Class Book Rev. Ed.,333. (1868)
Pirus iowensis Bailey Am. Garden XIL, 473. (1891)
Pirus coronaria L. of Gray’s Manual, as far as Nebraska and
other western specimens are concerned.

Crataegus mollis (T. & Gr.) Scheele Linnaea XXI., 569.
(1847)
Crataegus subvillosa Torr. P. R. Rep. IV., 86. (1856)
Crataegus coccinea mollis T. & Gr. FI. I, 465. (1838)
This is generally accepted as a good species.
Ribes rubrum albinervium (Michx.) Mac M. Met. Minn. Vall.,
279. (1892) :
Ribes albinervium Michx. Fl. 1,110. (1803)
Ribes rubrum subglandulosum Maxim Bull. Acad. Pet. 19,
261. (1878) +
Myriophyllum pinnatum (Walt.) B.S. P. Cat, N. ¥. (1888)
Potamogeton pinnatum Walt. Fl Car., 90. (1788)
Myriophyllum scabratum Michx. Fl. IL, 190. (1803)
Callitriche palustris L. Spee. Pl., 4. (1753)
Callitriche verna L. Specs Pl. Ed. 2,6. (1761)

36

Oenothera albicaulis Pursh Fl., 733 (1814), not O. albicaulis
Nutt. Gen. (1818)
Oenothera pinnatifida Nutt. Gen. L., 245. (1818)

As O. albicaulis Nutt. in Fraser’s catalogue is but a nomen.
nudum, it has no standing. Hence O. albicaulis Pursh is
the first published species bearing that name, which should
be restored, though apt to cause some confusion.

Oenothera pallida Lindl. Bot. Reg. 14 t. 1142. (1830)
Oenothera albicaulis Nutt. Gen. I, 245 (1818), which name
‘is preoccupied by the foregoing.
Epilobium angustifolium L, Spec. Pl. 347 (1753) not Lam.
Epilobium spicatum Lam. Fl. France. 1077. (1778)

This is corrected in Gray’s manual, but not in Coulter’s. Dr.
Trelease in his revision of Hpilobium changes it back to
Ei. spicatum, as he believes, as did Lamarck, that H. an-
gustifolium L. is the same as HE. dodonei Vill. * It would
have been strange if Linne had regarded this as the typi-
cal EL. angustifolium, as the species is comparatively rare
in Europe and not found at all in the native land of Linne.
What is most common in Sweden is a narrower leaved
form of EH. angustifolium L., E. spicatum Lam. This is
Linne’s EZ. angustifolium a. It grades into the broader
leaved form which is common here, Linne’s EF. angustt-
folium b, E. angustifolium latum DC. in Prodr. Linne’s
H. angustifolium ¢ is E. dodonet Vill: and HE. angustifo-
lium Lam.

Mentzelia decapetala (Pursh).
Bartonia decapetala Pursh in Sims Bot. Mag. t 1487 (between
1810 and 18138)
Bartonia ornata Pursh Fl. 327, (1814)
Mentzelia ornata T. & Gr. FL
Cactus viviparus Nutt. Gen. I, 295, (1818)
Mamillaria vivipara Haw. Syn. Pl. Succ. Supp. 72.

Cactus mamillaris, the type of the genus Mamillaria, Haw.,

is the first of the two species in Linne’s Species Plantarum .

37

belonging to that section of the genus Cactus L. which
has been regarded by Linne and others as representing
the typical cacti. The name Cacfus should therefore be
retained for this group. The name Mamillaria Haw. is
also, according to Dr. Kuntze, antedated by Mamillaria
Stackh. (1809)
Cactus missouriensis (Sweet) OK. Rev. Gen. IL, 259. (1891)
Mamillaria missourtensis Sweet Hort. Brit. 171. (1827)
Micrampelis lobata (Michx.) Greene Pittonia IT., 128. (1890)
Sicyos lobata Michx. Fl. IL., 217. (1803)
Micrampelis echinata Raf. Med. Repos. N.Y. V., 352. (1808)
Echinocystis lobata T. & Gr. Fl, N. A. I, 542. (1838)
Micrampelis was established some thirty-two years before
Echinocystis.
Osmorrhiza claytonii (Micbx.) B. 8. P. Cat. N. Y. (1888)
Myrrhis claylonti Michx. FI. I., 170. (1803)
Osmorrhiza brevistylis DC. Prodr. TV., 232. (1830)
Osmorrhiza aristata (Thunb. )
Chaerophyllum aristatum Thunb. FI. Japon. 119. (1784)
Osmorrhiza longistylis DC. 1.c.
Adorium tenuifolium (Nutt.) OK. Rev. Gen. 264. (1891)
Musenium tenuifolium Nutt. in Torr. & Gray Fl. I, 642.
(1840)
Adorium Raf. was published in 1825, Musenium T. & Gr.
in 1840.
Adorium divaricatum (Pursh).
Sesili divaricatum Pursh Fl. 732. (1814)
Musenium divaricatum Nutt. le (1840)
Dr. Kuntze writes A. lucidum, his name being based on
Sesili lucidum Nutt. in Fraser’s Catalogue, which is a
mere nomen nudum.

38

Peucedanum graveolens Wats. King’s Rep. V., 128. (1871)
Peucedanum kingii Wats. Proc. Am. Acad. XXII, 474.
(1887)

J. B. Davy, in Erythea IL, 48 (1894), points out that Ben-
tham & Hooker in Gen. Pl. L., 919 (1867), did not give
Anethmum graveolens L. the name Peucedanum graveo-
lens, but only indicated that it should be included in that
genus. The name Peucedanum graveolens was given to
the latter species by Baillon, Hist. d. Pl. VIL, 97 (1880),
some nine years later than the publication of P. graveo-
lens Watson.

Cymopterus acaulis (Pursh)
Selinum acaule Pursh Fl. 732. (1814)
Thapsia glomerata Nutt. Gen. I., 184. (1818)
Cymopterus glomeratus Raf. Journ. Phys. 100. (1819)
* Sanicula canadensis L. Spec. Pl. 235. (1753)
“ Sanicula marilandica canadensis Torr. Fl. U. 8. 302. (1829)

As 8. canadensis and S. marilandica are both on the same
page of the Species Plantarum, but S. canadensis is first,
the latter must keep its name. If one is to be regarded
asa variety of the other, as it generally is, S. marilandica
must take the place of variety; hence

Sanicula canadensis marilandica (L.)
Sanicula marilandica L. Spec. Pl., 235. (1753) °
Deeringia canadensis (.) OK. Rev. Gen., 266.. (1891)
Sison canadense L. Spec. Pl, 252. (1753)
Oryptotaenia canadensis DC, Mem. Umb., 42. (1829)
Deeringia Adanson was published in 1763, Cryptotaenia

DC. in 1829.
Beruiad erecta (Huds.) Coville Bot. Death Vall. Exp., 115.
(1893)

Siwm erectum Hudson Fl. Aug., 103. (1762)
Berula angustifolia Koch in Mert. & Koch Deut. Fl. IL, 455.
(1826)

39

Cicuta virosa maculata Coulter & Rose Rev. N. A. Umbel., 180.
(1888)
Cicuta maculata L. Spee. Pl., 256. (1753)
This is reduced to a variety by Coulter and Rose.
Cornus candidissima Marsh. Arb., 35. (1785)
Cornus stricta Lam, Dict, H., 116 (1786) and
Cornus paniculata L’Her. Corn, 9 t. 5. (1788)

A PretimiInary List or tHe BoranicaL ExpEpitions In Nr-
BRAska, 1803-1893.

BY FREDERICK E, CLEMENTS.

The object of the subjoined list is to furnish easy and ready
reference to botanical field work done within Nebraska as now
bounded, and also to aid in the survey of the stata by showing
in what region work has already been done and by affording
some hint as to the nature and extent of this work, the disposition
of collections, ete. The present list does not pretend to com-
pleteness by any means. It simply purports to be a fairly full
and accurate resume of the present status of our knowledge on
this subject and is published partly for reasons given above and
partly in the hope of obtaining further information through out-
side channels. This preliminary list is intended merely to cata-
logue such botanical excursions as have assumed the proportions
of expeditions and is in no degree a measure of all the field work
done in the state. _

I. Lewrs, Meriwether, and Crarx, William. (1803-1806)
Along the Missouri river from the southeast corner of
the state to the mouth of the Niobrara, with short excur-
sions into the state. Collections made on the outward
journey lost; those made on the return identified by Fred-
erick Pursh and new species described in his Flora Americae
Septentrionalis. (1814)

II.

Til.

IV.

40

Nurrat, Thomas, and Brapsury, John. (1808)
General route, up the Missouri; collected in Nebraska at
the mouth of the Platte, Council Bluffs (old Council Bluffs
on the Nebraska side), Blackbird, and the lower valley of
the L’Eau qui Court.
Collection in possession of the Academy of Natural Sci-
ences of Philadelphia. Descriptions of new species in Fra-
ser’s Catalogue (1813) and Nuttall’s Genera of North Ameri-
can Plants. (1818)

NicotteT, I. N. (1838-39)
Along the Missouri river with extensive excursions into
the eastern part of the state. Collections made by Charles
Geyer and identified by Dr. John Torrey. List in Nicollet’s
Report (1843) ; collection preserved in the Herbarium of Co-
lumbia College, New York.

Fremont, John 0. (1842-44)

(1842) Entered Nebraska at about the point where the
Little Blue leaves the state, followed up that river to its
head, came upon the Platte at Kearney, and followed the
South Platte out of the state.
Extensive collections throughout the valley of the Little
Blue and of the Platte; identified by Dr. John Torrey; some
descriptions published in Torrey & Gray’s Flora of North
America, and list published in Fremont’s Report (1845);
preserved in the Herbarium of Columbia College, New
York.

(1844) Passed’ through the southwest corner of the
state along the Republican. Greater part of the collections
lost.
Stansbury, Howard. (1849)
Entered the state in the southeast corner, followed the
Little Blue, reached the Platte at Kearney, and followed the
North Platte out of the state.
Collections identified by Dr. John Torrey, in the Herba-
rium of Columbia College; list in Stansbury’s report. (1855)

41

VI. Warren, Gouverneur K. (1855-57)
(1855) From the Middle Keya Paha nearly due south
through the Loup valley to Ft. Kearney. A mere military
reconnoisance without important botanical results.
(1856-57) From Sioux City southwestward through the
Elkhorn valley, thence northwest through the Loup valley to
Ft. Laramie. Return through tlie Niobrara valley to the
Missouri.
Collections mostly identified by Dr. George Engelmann
preserved in the Engelmann Herbarium at St. Louis. List
in Warren’s Report. (1858)

VII. Bessy, Charles E. (1887)
Along F. E. & M. V. R. RB. from Long Pine to Ft. Robin-
son. List in Webber’s Catalogue. (1890) Collection in
the Herbarium of the University of Nebraska.

VIII. Bessey, Charles E. (1889)
Followed survey of route of B. & M. R. R. from Alliance
to Pine Ridge. List in Webber’s Catalogue. Collection
in the Herbarium of the University of Nebraska.

IX. Smirn, Jared G. (1889)
From Alliance to Camp Clarke. Collection in the Survey
Herbarium.

X. Wesser, Herbert J. (1889)
In valley of the Dismal river. List in Webber’s Cata-
logue, Collection in the Survey Herbarium.

XI. Wesser, Herbert J. (1889)
Along the bluffs of the Missouri from Rulo to Nebraska
City. List in Webber’s Catalogue. Collection in the Sur-
vey Herbarium.

XII Winuiams, Thomas AW (1891)
In Hat Creek basin and the White River valley. Collec-
tion in Mr. Williams’ herbarium, a few specimens in the
Survey Herbarium. Additions published in Webber’s Ap-
pendix. (1892)

42

XIII. Rypvere, Per A.

From Kearney along B. & M. R. R. to the Colorado line;
thence along Lodge Pole creek and the South Platte to Wy-
oming. Collections in the National Herbarium at Wash-
ington and in the Survey Herbarium. Additions published
in Webber’s Appendix (1892), and Dr. Bessey’s Supple-
ment. (1892)

XIV. Woons, Albert F. (1892)

Hat Creek basin. Collection in the Survey Herbarium.
List in Report of the Survey for 1892.

XV. Smiru, Jared G., and Pounp, Roscoe. (1892)

From Alliance to O’Neill through the sand hills and lake
region; thence to Columbus. Collection in the Survey
Herbarium. List in report of the survey for 1892.

XVI. Ryppera, Per A. (1893)

Sand hills of central Nebraska and Dismal River valley.
Collections in the National Herbarium at Washington and
in the Survey Herbarium. Additions published in this
report.

XVII. Woops, Albert F., and Saunpers, DeAlton. (1893)
From Haigler to Superior along the Republican, thence
to Endicott and Fairbury on the Little Blue. Collection in
the Survey Herbarium. Additions published in this report.

XVIII. Cuements, Frederick E. (1893)

From Emerson along the Missouri and Niobrara to West-
ern Brown county. Collections in the National Herbarium
at Washington and in the Survey Herbarium. Additions
published in this report.

In addition, mention should be made of the collections made
by Rev. J. M. Bates along the Elkhorn and Niobrara between
Ewing and Ft. Robinson, and by Dr. H. Hapeman in Kearney
and Adams counties.

43

BIBLIOGRAPHY OF THE FiLoRA oF NEBRASKA.
BY ROSCOE POUND.

The following list contains such books or articles as deal with
the flora of Nebraska or with the flora of localities within the
state, and such other articles as have to do with collections made
in Nebraska, or describe new species from the state, or are other-
wise of local interest.

A few words seem to be required with reference to Professor
Aughey’s Catalogue and his sketches of the Flora of Nebraska,
enumerated below, as they have deceived many persons in times
past. In the catalogue he enumerates 2,034 species, of which
1,671 are Anthophytes, 49 Pteridophytes, 163 Bryophytes, 90
Alge, and 61 Lichens. No fungi are catalogued. Elsewhere he
states that 2,043 species are known to exist in Nebraska. These,
however, are only estimates. Professor Aughey was primarily a
geologist. His heart was in geological work, and the bulk of
what time he had after the labors of the class room was devoted ©
to it. His herbarium is now in the Herbarium of the University
and shows what he actually accomplished as regards the flora of
the state. It consists of about 500 specimens, representing less
than 200 species, all Anthophytes or Pteridophytes, and almost
all from the south-eastern portion of the state. Very few, there-
fore, of the species reported in the catalogue are represented, and
a comparison has shown (as was noted by Mr. Webber in the in-
introduction to his catalogue) that the list was based almost en-
tirely upon the range of species as given in other books. In
other words, its purpose evidently was to inform the collectors of
the state of what they might expect to find in its borders. At
that early day, with the manifold duties of his chair, then undi-
vided, with no adequate library facilities, few helpers, and a
large unexplored region before him, perhaps nothing more could

44

be expected. At any rate it must be said that subsequent re-
searches have failed to confirm his estimates, and that, though some
of the eastern plants he listed are now beginning to make their way
into the state at a distance of nearly twenty years, his catalogue
is substantially unreliable. It seems necessary to say this because
many species are to be found cited as occurring in Nebraska by
writers who have depended on his catalogue, which in fact have
never been collected in the state.

Aughey, Samuel. Catalogue of the Flora of Nebraska 1875.

Sketches in the Physical Geography and Geology of Ne-
braska (1880). [ Contains: chapter VII. General Flora of Ne-
braska; VIIE. Forest Trees and Shrubs of Nebraska with
Notes on their Distribution; IX. The Wild Fruits of Ne-
braska; X. Wild Grasses. |
See Curley.

Bates, J. M. The Grasses of Northwestern Nebraska. In Re-
port of the Botanist in Rep. Nebr. St. Board of Agr. 1891.
(1892)

Bell, A. T. The Slime Moulds (Myxomycetes) of Crete.

In Publ. Nebr. Acad. Sci. II. (1892)

Berkeley, M. J. Notices of North American Fungi.

Grevillea, 1876, pp. 98 and 141. [Describes two new black
fungi from Nebraska, collected by Hayden. No, 881, and
No. 969.]

Bessey, C. E. Ruppia maritima L. in Nebraska. Am. Nat.,
1886, p. 1052.

Grasses and Forage Plants of Nebraaks, In Rep. Nebr. St.
Agr. Soc., 1886. (1887)

The Hastward Extension of Pinus ponderosa Dougl. var.
scopulornm. Am, Nat., 1887, p. 927.

The Westward Extension of the Black Walnut. Ibid., p. 928.

The Grass-Flora of the Nebraska Plains Am. Nat., 1888, p.
171.

45

Grasses and Forage Plants of Nebraska. Second Report. In
Rep. Nebr. St. Board Agr., 1887. (1888).

Natural Horticultural Regions of Nebraska. In Rep. Nebr.
St. Hort. Soc., 1887-8. * (1888) [Gives a list of the trees
and woody plants of the state and their distribution. |

A few notable weeds of the Nebraska Plains. Am. Nat.,
December, 1888.

Report on the Grasses and Forage Plants of Nebraska. In
Rep. Nebr. St. Board of Agr., 1888. (1889)

Two Big-rooted Plants of the Plains. Am. Nat., 1889, p. 174.

The Flora of the Upper Niobrara. Am. Nat., 1889, p. 537.

Report of the Botanist on the Grasses and Forage Plants of
Nebraska. In Rep. Nebr. St. Board of Agr., 1889. (1890)
[ Contains: Grasses of Central Nebraska by H. J. Webber;
Grasses of Northwestern Nebraska, by H. J. Webber;
Grasses of Box Butte and Cheyenne counties, by J. G.
Smith; List of Grasses Exhibited at State Fair, 1888, show-
ing the distribution of many species. |

The Bearberry in Central Nebraska. Am. Nat., 1891, p. 1130.

The Native Trees of Nebraska. In Nebraska Farmer, 1891,
page 537. [Gives a list with distribution. |

The Native Shrubs of Nebraska. In Nebraska Farmer 1891,
p. 590. [List with distribution. |

Preliminary Report on the Native Trees and Shrubs of Ne-
braska. Bull Agr. Exp. Sta, Nebr., Vol. IV, No. 4.
(1891)

Sixth Annual Report of the Botanist. In Rep. Nebr. St.
Board Agr., 1891. Also in Contrib. Bot. Dept. Univ. Neb.,
n. s., II. (1892) [Contains: Grasses Exhibited at State
Fair, 1891, showing distribution; List of Weeds of Nebraska;
Preliminary List of the Grasses of Nebraska; Grasses of
Northwestern Nebraska, by J. M. Bates; Grasses of South-
western Nebraska. |

46

Second Edition of Webber’s Appendix to the Catalogue of
the Flora of Nebraska, with a Supplementary List of Recently
Reported Species. In Contrib. Bot. Dept., Univ. Neb., n.
s. III. (1892)

Second Report upon the Native Trees and Shrubs of Ne-
braska. In Rep. Neb. Hort. Soc., 1892. Also in Contrib.
Bot. Dept. Univ. Neb., n.s., I. (1892)

Seventh Annual Report of the Botanist. In Rep. Neb. St.
Board Agr., 1592. Also in Contrib. Bot. Dept. Univ. Neb,
n.s, V. (1893) [Contains: List of Weeds of Nebraska;
List of Grasses Exhibited at the State Fair, 1892, showing
distribution; Preliminary Description of the Native and In-
troduced Grasses of Nebraska. |

Botanical Survey of Nebraska.—-Report on Collections Made in
1892. (1893) [Contains Flora of the Sand Hill Region of
Sheridan and Cherry Counties, and List of Plants Collected
on a Journey Through the Sand Hills in July and August,
1892, by J. G. Smith and Roscoe Pound; Notes on the Can-
yon Flora of Sioux County, with List of Plants Collected in
July and August, 1892, by A. F. Woods; Miscellaneous Ad-
ditions to the Flora of the State and New or Noteworthy Spe-
cies from Various Localities. |

Coulter, John M. Manual of the Botany (Phaenogamia and
Pleridophyta) of the Rocky Mountain Region, from New
Mexico to the British Boundary. 1885, [Covers western
Nebraska to the hundredth meridian. |

Curley, Edwin A. Nebraska: its Advantages, Resources, and
Drawbacks, 1876. [Contains chapter XXIV., The Wild
Fruits of Nebraska, by 8S. Aughey, in which is also a sketch
of the “General Botany of Nebraska.” |

Ellis, J. B.,and Everhart, B. M. New Species of Fungi from
Various Localities. Journ. Myc. IV., 97. (1888)

New Species of Hyphomycetous Fungi. Journ. Mye. V., 68.
(1889)

47

New and Rare Species of North American Fungi. Journ.
Mye. V., 145. (1889)

New Species of Fungi from Various Localities. In Proc.
Acad. Nat. Sci. Philad., 1891. [In each of the foregoing
articles new species from Nebraska are described. |

Fremont, John ©. Report of the Exploring Expedition to the
Rocky Mountains in the Year 1842, and to Oregon and
North California in the Years 1843-44. (1845) [ Contains:
Catalogue of Plants Collected by Lieutenant Fremont in his
Expedition to the Rocky Mountains. By John Torrey. |

Gray, Asa. Manual of the Botany of Northern United States,
Including the District East of the Mississippi and North of
North Carolina and Tennessee. Sixth Edition Revised and
Extended Westward to the Hundredth Meridian by Sereno
Watson and John M. Coulter, 1890. [This edition (sixth)
connects with Coulter’s Manual and includes the Flora of
eastern and central Nebraska. |

Morgan, A. P. The Genus Geaster. Am. Nat., 1887, p. 1026.
[ Describes two new species from Nebraska. | :

Nicollet, I. N. Report Intended to Illustrate a Map of the Hy-
drographical Basin of the Upper Mississippi River, 1843.
[Contains: Catalogue of Plants Collected by Mr. Charles
Geyer, under the Direction of Mr. I. N. Nicollet, During his
Exploration of the Region Between the Mississippi and Mis-
souri Rivers, by Professor John Torrey, M.D. (appendix B.) |

Pound, Roscoe. Notes on Fungi of Economic Interest Observed
in Lancaster County During the Summer of 1889. In Bull.
of Agr. Exp. St. Nebr., Vol. I., No. 11, 1889.

Rydberg, P. A. Flora of the High Nebraska Plains. Am.
Nat. 1891, p. 485.

On the American Black Cottonwood. In Bull. Torr. Bot.
Club XX., No. 2. (1893) | Describes a new cottonwood
from Nebraska. |

Schofield, J. R. Notes on the Flora on the Artesian Well. In
Publ. Nebr. Acad. Sci., II (1892) [Gives a list of Algze
found in the artesian well at Lincoln. |

48

Smith, J. G. Some Nebraska Grasses. Bot. Gaz., 1889, p. 231.

The Grasses of Box Butte and Cheyenne counties. In Rep.

Nebr. St. Board of Agr., 1889. (1890) Also in Am. Nat.,
1890, p. 181.

Grasses of the Sand Hills of Northern Nebraska. In Rep.
Nebr. St. Board of Agr., 1892. (1893) Also in Contrib. Bot.
Dept. Univ. Nebr., n. s. V.

Stansbury, Howard. Exploration and Survey of the Valley of
Great Salt Lake of Utah, Including a Reconnoisance of a New
Route Through the Rocky Mountains. 1853. [Pages 18-
52 relate to Nebraska and its prairie flora.

Swezey,G. D. Nebraska Flowering Plants. Doane College
Nat. Hist. Studies, 1. 1891. [List and notes].

Additions to the Flora of Nebraska. In Publ. Nebr. Acad.
Sci., II. 1892. Also in Bull. Torrey, Bot. Club, 1892, p. 94.

Torrey, John. See Fremont, Nicollet.

Warren, G. K. Report on Explorations in Nebraska in 1855-
56-57. In Report of the Secretary of War, 1858. [| Bot-
any by F. V. Hayden, at page 726. |

Watson, Sereno. Pentsiemon haydent. Bot. Gaz., 1891, p. 311.
[Notes the rediscovery of this species in Nebraska,

Williams, T. A. Notes on Nebraska Lichens. Am. Nat., March,
1889.

Notes on the Canyon Flora of Northwest Nebraska. Am.
Nat., 1890, p. 779.

Webber, H. J. A Preliminary Enumeration of the Rusts and
Smuts of Nebraska. In Bull. Agr. Exp. Stn. Nebr., Vol. L.,
No. 11, 1889. | Introduction by Dr. ©. E. Bessey. |

The Fresh Water Alge of the Plains. Am. Nat., 1889, p.
1011.

The Flora of Central Nebraska. Am. Nat., 1889, p. 633, 1890,
p. 76.

The Grasses of Central Nebraska. In Rep. Neb. St. Board
Agr., 1889, (1890)

The Grasses of Northwestern Nebraska. In Rep. Neb. St.
Board Agr., 1889. (1890)

Catalogue of the Flora of Nebraska. In Rep. Neb. St. Board
Agr., 1889. (1890) Also reprinted from the Report by
the University, 1890.

Appendix to Catalogue of the Flora of Nebraska. In Trans,
St. Louis Acad. Sei. VI, 1, 1892.

UNIVERSITY OF NEBRASKA.

BoTANICAL SURVEY OF NEBRASKA.

Conducted by the Botanical Seminar.

LV.
Report on Collections Made in 1894-95.

LINCOLN, NEBRASKA, U. S. A.
Published by the Seminar.
, 1896.
(Distributed January 20, 1896.)

CONTENTS,

New Species of Baae1, 24 cuss cern weanerwe vases semis
Additions to the Reported Flora of the State..............

SUMMALY 2... caxsc cose scar cree soca esee deh een wees eas

NOTE.

The large number of new species of fungi collected in 1894
delayed the publication so long that we have been able to include
in this report a portion of the collections made in 1895. This
report is given over entirely to recording additions to our flora,
and to descriptions of fungi, the space being fully occupied by
them. Work upon the distribution of species of anthophytes in
the state is rapidly approaching completion, but is not yet ripe
for publication.

The Seminar is indebted to Rev. J. M. Bates, Dr. H. Hape-
man, and Messrs. C. L. Shear, M. E. Moore, J. A Warren, and
C. C. Engberg for collections. Many others have assisted by
sending single specimens. Thanks are due also to Dr. N. L.
Britton of Columbia College, New York, for advice and informa-
tion as to nomenclature.

The list of Anthophyta was prepared by P. A. Rydberg, the
algae, except Bacillariaceae by D. A. Saunders, the Bacillaria-
ceae by C. J. Elmore, the fungi by Roscoe Pound and Frederick
E. Clements.

From the amount of material already on hand and undeter-
mined, we feel justified in prophesying a total of four thousand
species in the next two years.

CHAr.es E. Bessey,
Roscoe Pounp,
FREDERICK E. CLEMENTS,
Editorial Committee.
December 23, 1895.

NEW SPECIES OF FUNGL

In the following descriptions of new species, Saccardo’s
Chromotaxia has been faithfully followed. All color-names con-
form to his charts and to the synonymic lists on p. 6ff.

MUCORACEAE.

Thamnidium (Helicostylum) cyanewm Pound and Clements.
Terminal sporangium, sporangiophore, and lateral branches
as in T. glomeratum,; sporangiola borne on the lateral
branches, numerous, 80-50, globose or pear-shaped, nod-
ding on deflexed stalks 100x3-5 pv, without columella, steel-
blue, 35-45 » in diam., 15—-35-spored; spores ellipsoid or
ovate, smooth, blue, in age pale blue, 12-15x8-10 py.
On horse-dung, with Piptocephalis, and Circinella, Lincoln.
(4493)

SPHAERIOIDEAE.

Cytospora celastri Clements.

Perithecia innate, densely aggregated, globulose, ostiole
short, erumpent, shorter than the perithecium; spore-
masses linear, flexuose-contorted, golden-yellow; conidia
hyaline, strongly curved, often semi-circular, obtuse, or
acute, 15—20x1 yp.

In dead stems of Celastrus scandens, Otowanie Woods,
(4742)

MUCEDINACEAE,

Rhinotrichum doliolum Pound and Clements.

Effused, white, compact, velvety, gray, or drab; sporophore
ascending, much branched; filaments hyaline, tortuous,
many septate, 5 4 wide, thickly beset with bottle-shaped
basidia, 7-8x3-4 y, generally opposite, rarely alternate;

6

conidia 2-several on each basidium, borne on short sterig-
mata, hyaline, ovoid-ellipsoid, 3-5x2-3 ps.

Forming a thick crust on the sporangia and stipes of a
slime-mould, bluffs of the Missouri river, Bellevue.
(4881)

Mycogone roseola Pound and Clements.

Broadly effused, covering the entire host with a layer 300-
-500 y thick, at first white, then rosy, or, rarely, pale
brick-red; hyphae hyaline, septate, erect, branched, 3-4
wide; conidia borne on short, lateral, often nodding ped-
icels, 2-celled, 20x15 y, superior locule larger, densely and
beautifully echinulate, globose, pale brick-red, 12-1 5 yp,
inferior locule almost hyaline, or very pale rosy, minutely
and sparingly punctulate, 8-9 y.

Parasitic on an Helvella, H. albipes (?), Meadville, Keya
Paha county. (4748)

DEMATIACEAE.
Helminthosporium phragmidium Pound and Clements.

Broadly effused, velutinous, at first white, then exactly avel-
laneous, 1 em. wide; sporophore very long, with numer-
ous alternately-disposed, lateral branches, multiseptate,
hyaline, 160-300x24—5 yw; conidia solitary, erect, obclavate,
smooth, pale gray, constricted between the septa, 3—7-sep-
tate, 45-70x10-15 yp.

On fragments of wood in the green-house, Lincoln. (4576)

Sporodesmium suffultum Pound and Clements.

Cespitula gregarious, superficial, granular, botryoid, black;
sterile hyphae creeping, fuliginous, branched, torulose;
sporophore erect, unicellular, broad, turgid, hyaline, equal-
ling the conidia in diameter, 25-35x15-20 y; conidia
densely congested, globose, or globose-oblong, rarely ob-
long, opaque, brown-fuscous, irregularly and densely poly-
gono-areolate, or nearly radiately septate, very rarely
muriform, 25-35x25 p.

7

On decorticated branches of Populus monilifera, Memphis.
(4578)

STILBAOEAE.

Trichurus Clements and Shear nov. gen.

As in Slysanus, but the capitulum densely beset with long
strict bristles.

Trichurus cylindricus Clements and Shear.

Solitary or gregarious; stipe simple, or sometimes two aris-
ing from the black base, attenuate above within the capit-
ulum, strict, erect, broad, glabrous, black, opaque, com-
posed of indistinct hyphae 24 » wide, $-24 mm. long,
35-85 y thick; capitula elongate, linear or clavate-cylin-
drical, equal, or sometimes attenuate towards the apex,
gray-fuscous, #-24 mm. long, 18-30 y thick, densely be-
set with acute, rectilinear, fuscous, few-septate, simple,
or rarely 2-3-fureate bristles, 60-120x2 #; hyphae brown-
ish-fuscous, short, pseudo-verticillately, or ramosely
branched; conidia catenulate, oblong-elliptical, smooth,
slightly glaucous, 8-9x3 yp.

On decaying seeds of Cucurbita maxima, in the laboratory,
Lincoln. (4744)

TUBERCULARIACEAE.

Fusarium hymenula Pound and Clements.

Sporodochia minute, ~,—}mm., gregarious, orbicular, or ob-
long, disciform, without white-tomentose, within at first
dilutely amber-colored, then black, margin slightly ele-
vated, flexuous, white; sporophore long, 2—-4—verticillately
branched, branches short, ascending, or erect, appressed,
35-40x2 »; conidia oblong, wider toward either end,
simple, rounded, straight, hyaline, 10-12x3-4 yp.

On dead leaves of Heliathus, Wabash. An Hymenula, with
verticillately-branched sporophore. (4258)

8

Volutella gilva albo-pilosa Pound and Clements.

On dead leaves of Ulmus fulva, Weeping Water. (4546)

According to Sacc. Fung. Ital., Fig. 728, the specimens in
the Survey collection are specifically distinct from V.
gilva. In Syll. Fung., Saccardo unites with V. gilva V.
intricata Karst., from which the specimens in hand differ
only in the atro-olivaceous, or nearly black sporodochium,
covered by the longer, inextricably interwoven, white
hairs.

HELVELLACEAE.
Helwella grisea Clements.

Pileus appressed, persistently bilobed, or sub-reniform,
scarcely inflated, reticulated beneath with numerous anas-
tomosing veins, pallid, hymenium pale brownish-gray;
stipe concolorous, or scarcely paler, glabrous, at first
longitudinally sulcate, then strongly lacunose-sulcate;
asci cylindrical, 8-spored, 200—250x15 yp; sporidia broadly
elliptical, monostichous, 1-guttate, 18x10 4; paraphyses

' filiform, septate, hyaline, 4 4 wide.

Pileus 1-2 cm. high, 1-24 cm. wide; stipe 14-3 cm. x 4-5
mm.

On the ground, with Conocephalus conicus, Hazel Creek
canyons, Brown county. Related to H. palustris Peck,
and to H. palescens Schaeff., but distinguished by the
color and the persistently saddle-shaped pileus.

Helvella suleata minor Clements. |

Pileus 2-3 mm., rarely 8 mm. wide, 2-5 mm. high; stipe
2-3 mm., rarely 10 mm. high, 14-34 mm. wide; sporidia
15x10 ws

On shady ground, Otowanie Woods, Lancaster county.

PEZIZACEAE.

Peziza brunneo-vinosa Clements.
Ascomata caespitose, sessile, at first cupuliform, at length
applanate, often exactly disciform and immarginate, mar-

9

gin irregular, hardly lobed, 5-12 mm. in diameter; hy.
menium deep brown-wine-color, beneath paler, or orchra-
-ceous; asci cylindrical, not turning blue with iodine, 250-
300x12-14 yw; sporidia ellipsoid, smooth, 2-guttate, 16-
20x10 #; paraphyses broadly linear, septate, fuliginous
above.

‘On sand in canyons of the Niobrara river, Keya Paha
counties.

Peziza paraphysata Clements.

Ascoma orbicular, applanate, margin deflexed, carnose, be-
neath fusco-ochraceous, hymenium chestnut-colored, 1-2
em. in diameter; asci cylindrical, 8-spored, elongate, not
turning blue with iodine, 325-350x18 yw; sporidia broadly
ellipsoid, obliquely monostichous, 2-guttate, smooth, 20x
15 w; paraphyses septate, broadly clavate above, densely
filled with brown granules, 5 wide, clavate apex 50-60 p,
long by 10-124 yp wide. ,

On the ground and on fragments of wood, Meadville, Keya
Paha county. Closely related to Discina orbicularis
Peck.

Peziza (Plicaria) vinacea Clements.

Ascoma concave, or scutellate, at length applanate, carnose,
sessile, margin repand-flexuous, surface of the hymenium
uneven, at first orange-vinous, then vinous-brick-colored,
beneath even, glabrous, paler, 7-15 mm. in diam.; asci
cylindrical, 8-spored, trunculate, turning blue throughout
with iodine, 225—250x12-13 w; sporidia elliptical, eguttu-
late, monostichous, hyaline, smooth, 16-20x10-12 y; par-
aphyses broadly filiform, scarcely incrassate at the apex,
granular, 5 » wide.

On damp ground in shady woods, Wabash.

Galactinia viridi-tincta Clements.

Ascoma hemispherical, cupulate, sessile, milky, without gray-

ish-tomentose, or minutely verrucose, light-olivaceous,

10

hymenium brownish-olivaceous, flesh turning green wher
wounded, milk grayish-green, 5-10 mm. wide; asci cylin-
drical, turning blue with iodine, 250-300x12-14 ; spor-
idia ellipsoid, 1-2-guttate, irregularly disposed, smooth,
15x18 ~; paraphyses linear, scarcely, or not at all, incras-
sate, multiseptae, hyaline, 5-7 p» wide.

On shady ground, Otowanie Woods, Lancaster county.

Barlaea constellatio minuta Clements.

Ascomata generally immarginate, convex, aurantiaceous,
rarely reddening with age, 4-4 mm., rarely as much as 1
mm., in diam.

On wet ground, Rock Creek, Keya Paha county.

HAumaria clausa Clements.

Ascomata caespitose, carnose, subglobose, or nearly hemis-.
pherical, mouth somewhat hysteriform, gaping slightly,
pruinulose, drab, #-2 mm., wide; asci clavate, 8-spored,
250x385 »; sporidia iarge, oblong, smooth, hyaline, egut-
tulate, 32-37x124-16y; paraphyses densely packed, fili-.
form, scarcely incracsate above.

On moist ground, Otowanie Woods, Lancaster county.

Humaria phycophila Clements.

Ascomata very minute, sessile, scutellate. at length con-
vex, gregarious, margin entire; hymenium incarnate, or
miniate-aurantiaceous, paler without, 300-500, in diam.;
asci clavate-cylindrical, obliquely operculate, 8-spored,
not turning blue with iodine, 60-67x9-15yu; sporidia
elliptical, obliquely monostichous, or often distichous,
slightly truncate at both ends, generally 1-guttate, smooth,
hyaline, 10-11, rarely 124, by 6-74 4; paraphyses filiform,
furcate above, stuffed with orange granules, strongly re-
curved at the apex, 1-2 w in diam

Among filaments of Lyngbya on moist ground, Beatrice. A
true Humaria, though in some degree related to
Ascophanus.

11

’

Humaria subcrenulata Clements.

Ascoma carnose, with a very short, thick, hy pogaeous.
stipe, at first globose, then hemispherical, or sometimes
almost concave, margin slightly incurved, subcrenulate,.
ochroleucous, or ochraceous, 2--5 mm. wide; asci narrowly
cylindrical, stipitate, 200x10y; sporidia ellipsoid, hyaline,
smooth, eguttulate, 124-15x8-10 y#; paraphyses scarcely
equalling the asci, filiform, septate, granular, 3 wide.

Among mosses on sandy ground, Rock Creek, Keya Paha
county; canyons of Hazel Creek, Brown county.

Humaria tofacea Clements.

Ascoma sessile, carnose, concave, naked, grayish-drab, scarcely
margined, or the margin strongly depressed, 2—3 cm. wide;.
asci cylindrical, not turning blue with iodine, 200x10-12
#3 sporidia ellipsoid, smooth, eguttulate, monostichous,
15x8—9 ; paraphyses filiform, 24 » wide.

On fragments of the wood of Pinus ponderosa, canyons of
the Niobrara river, Keya Paha county.

Sarcoscypha roseo-tincta Clements.

Ascomata caespitose, cupuliform, at length often concave,
carnose, without beautifully papillate-tomentose, with
densely agglutinated cells, 20-25 yw in diam., white, mar-
gin tomentose-ciliate-crenate, sordescent in age; hyme-
nium creamy-ochraceous; stipe broad, rarely 1—-3-lacunose,
tomentose-papillate, expanded above into the cup, rosy,
or rosy-tinged; asci cylindrical, 8-spored, not turning blue
with iodine, 125x8-10 yw; sporidia ellipsoid, hyaline, mon-
ostichous, 2-guttate, 10x5 4; paraphyses linear, stuffed
with 1-2-seriate oil-drops above, 24 » wide.

On horse-dung, Otowanie Woods, Lancaster county.

Sepultaria Cooke Myc. 259, 1879, Lachnea Fr. Syst. Myc. 2:77,
1822; not Lachnaea L. Sp. Pl. Ed. 1, 560, 1753 (Lachnea
Sp. Pl. Ed. IL, 514). Fries cites Lachnum Retz. Flor.
Scand. Prod. 329, 1797, as a synonym of Lachnea. Lach-

12

num agaricinum Retz., however, is Dasyscypha virginea
(Batsch) Fekl.; hence Lachnum Retz. must stand for the
Friesian genus Dasyscypha. In consequence, Sepultaria
Cooke is the oldest admissible name, for Luchnea Fr.
Kuntze, Rev. Gen. Pl. 868 takes up Scutellinia Cooke, in
accordance with his rule of species. majority, a principle
not sanctioned by American botanists.
Sepultaria (Husepultaria) aspera Clements.

Ascoma broadly cupulate, partly subterranean, waxy-carnose,
covered with short, thick, flexuous, smoky-brown, 38-6-
celled hairs, 80-200x12-15 yu, chestnut-colored, margin
irregularly 3-4-lobed; hymenium bay-chestnut-colored ;
asci cylindrical, not turning blue with iodine, 200x124-15
#; sporidia fusoid-elliptical, 2-3 guttate, hyaline, monosti-
chous, very prominently tuberculate-verrucose, 25x124 py;
paraphyses entirely fusco-olivaceous, clavulate, 7-8 yu
wide.

Ascoma 3 cm. high, 2 em. wide.

On shady ground, bluffs of the Missouri river, Bellevue.
Related to 8. fusicarpa (Ger.) Cooke, but easily dis-
tinguished by the lobed margin, sparse hairs, and tuber-
culate spores.

Sepultaria (Husepultaria) aurantia Clements.

Ascoma subhypogaeous, hemispherical-cupulate, without
fuscous-brown, densely covered with very long, septate,
concolorous hairs, 500-600x10 4; hymenium bright or-
ange, 5-7 mm. wide; asci narrowly cylindrical, long-
stipitate, not turning blue with iodine, 250x8-10 4; spo-
ridia ellipsoid, smooth, monostichous, 1—-guttate, 16—18x8-
9 4; paraphyses filiform, filled with orange granules, 2h yu
wide.

On the ground among dead leaves, bluffs of the Missouri
river, Bellevue. Related to S. lapidaria Cooke; the form
and color of the cup are that of S. hemisphaerica (Wigg. )
Cooke.

18

Sepultaria (Husepultaria) grisea Clements.

Ascomata subterranean, gregarious, often crowded, hemis-
spherical-cupulate, without sparsely covered with septate,
flexuous hairs, pale brown, or isabel-colored below, hyaline
toward the apex, 150—400x6—7 py, brown-ochraceous, hy-
menium gray, 3-4 mm. wide; asci broadly cylindrical,
8-spored, 200x15—-20 4; sporidia gllipsoid, smooth, 1—2—
guttate, monostichous, 20—25x124-15 4; paraphyses grad-
ually but strongly clavate, 7-8 » wide above.

Among mosses on wet sand, Rock Creek canyon, Keya Paha
county.

Sepultaria (Scutellinia) bryophila Clements.

Ascomata gregarious, hemispherical, then deeply scutellate,
margin and external surface furnished with septate, brown,
obtuse or acuminate hairs, 250-400x8-10 w#, hymenium
concave, gray, with a pale but distinct rosy tint, 1-2 mm.
wide; asci cylindrical, 8-spored, 250-300x12-14 »; spo-
ridia elliptical, hyaline, smooth, minutely 2-guttulate,
16-20x10-12 »; paraphyses guttulate, filiform, 3-4
wide.

On sandy ground among mosses, Rock Creek Canyon, Keya
Paha county. Related to Sepultaria cretea (Cooke).

Sepultaria (Scutellinia) pediseta Clements.

Ascomata gregarious, or caespitose, at first hemispherical,
scarcely open, then scutellate, without tomentose-tubercu-
late, the tubercules pale vellow, composed of agglutin-
ated cells 20-25 » in diam.; bristles sparse, very long,
strict, strongly attenuate, pale brown, 9-10-septate, 450—
500x18 p» at the base, 5 » at the apex, arising singly from
the tubercules; hymenium bright orange, paler without,
3-5 mm. in diam.; asci cylindrical, not turning blue with
iodine, 175x10 y; sporidia ellipsoid, smooth, monostich-
ous, 15x8 »; paraphyses scarcely broader above, 5 » wide
at the apex, slightly green-tinted.

14

On horse dung, Otowanie Woods, Lancaster county. Re-
lated to S. dalmeniensis (Cooke).

Sepultaria (Scutellinia) pseudocrenulata Clements.

Ascomata deeply concave, carnose; hymenium exactly drab,
paler without, furnished with short, septate, nearly hyaline
hairs, 80-100 » long, margin crenulate with fasciculate
hairs, 5 mm. wide; asci cylindrical, 8-spored, 200-225x
12-15 y; sporidia ellipsoid, smooth, hyaline, monostichous,
18x10 #; paraphyses filiform, scarcely incrassate above.

On rich, shady ground among filaments of Lyngbya, Oto-
wanie Woods, Lancaster county. Related to S. laxwmanni
(Weinm).

Sepultaria (Scutellinia) punicea Clements.

Ascomata subgregarious, superficial, or slightly innate, ‘at
first hemispherical, closed, then narrowly open, mouth
densely beset with bristles, without furnished with very
dense, brown, septate, acute bristles, 300-400x16-20 yp;
hymenium bright miniate, 4-2 mm. in diam.; asci cylin-
drical, 225-230x10-14 y; sporidia elliptical, smooth, hya-
line, monostichous, 10-12x7-9 y; paraphyses filiform-clay-
ulate, densely filled with orange granules.

On wet, decaying wood, bluffs of the Missouri River, Otoe
county.

Sepultaria (Scutellinia) pygmaea Clements.

Ascomata very minute, 3-? mm., rarely 1 mm. in diam.,
gregarious, carnose, scutellate; hymenium gray or fuscous,
margin and external surface furnished with very strict
brown, septate, acute, or often truncate hairs, 175-250x124
#3 asci cylindrical, 125-150x9-10 yp; sporidia ellipsoid,
smooth, 12x7 “4; paraphyses exceptionally numerous,
filiform.

On rich ground among filaments of Lyngbya, Otowanie
woods, Lancaster county. Related to S. bryophila.

15

Sepultaria (Scutellinia) rubro-purpurea Clements.

Ascomata at first urceolate, then cupulate, very rarely some-
what scutellate, without brownish-fuliginous, very densely
covered with rigid, concolorous, many-septate hairs,
rounded at the apex, 150-200x8-10 yw, margin scarcely
distinctly ciliate, hymenium bright red-purple, 3-5 mm.
in diam. ; asci cylindrical, turning bright green with iodine,
250x15-18 4; sporidia ellipsoid, verrucose, 2-guttate,
monostichous, 23—-25x124 u; paraphyses septate, red-pur-
ple, 3-4 w wide, abruptly incrassate above, 7 » wide.

On the sandy banks of a brook, Hazel Creek Canyons, BrowD
county. Related to S. cubensis (Berk.).

Pseudohelotium isabellinum Clements.

Ascoma cupulate, stipitate, margin thick, often flexuous;
hymenium concave, isabel-colored, or pale fulvous, paler
beneath, puberulent with short hairs, 25-40x8-10 w, 4-2
mm. in diam.; stipe short, 4-4 mm.; asci cylindrical, not
turning blue with iodine, 75-95x6-7 y, sporida oblong,
monostichous, 7-124x5 4; paraphyses densely filled with
large oil-drops.

On wet twigs, Rock Creek, Keya Paha county.

Mollisia lilacina Clements.

Ascomata gregarious, sessile, disciform, lilac cr pale livid,
testaceous when dry, paler beneath, margin elevated,
white-crenulate, 4-1 mm. in diam.; asci small, clavate,
stipitate, 30-40x3-4 yw; sporidia cylindrical, straight or
curved, 1-3-guttate, or spuviously septate, distichous or
monostichous, 7-10x14-2 #4; paraphyses cylindrical, gran-
ular, 2 # wide.

On bark of Ulmus americana, Wabash; on decaying twigs,
Bellevue, Beatrice, Nebraska City.

Trichopeziza candida Clements.

Ascomata caespitose, sessile, waxy, tenacious, broadly in-

fundibuliform, or scutellate, pure white within and with-

16

out, disk becoming cinereous in age, exterior very densely
covered with long, hyaline hairs roughened with minute,
crowded granules, margin beautifully ciliate, crispate-
lobate, incurved; asci clavulate, somewhat acute at the
apex, 75—-100x5-8 y; sporidia lacking.

On bark and twigs of Tilia americana, Wabash. Possibly
Trichopeziza tiliae (Peck) Sace.

Phaeopezia elaeodes Clements.

Ascoma hemispherical-cupulate, rarely scutellate, waxy
sessile, beautifully verrucose without, brownish-black;
hymenium exactly olivaceous, margin often irregular,
flexuous; asci cylindrical, truncate, 8-spored, 200—-300x15.
-18 »; sporidia monostichous, spherical, with a large oil-
drop, 8 » in diam. densely concentrically verruculose,
fuscous, 12-15 » in diam.; paraphyses linear, many-sep-
tate, 5-6 mw wide.

Ascoma 8-20 mm. wide, 5-13 mm. high.

On wet, sandy banks, Hazel Creek Canyons, Brown county,

Phaeopezia vinacea Clements.

Ascoma at first broadly cupulate or concave, then applanate,
sessile, carnose, without pale brownish-verrucose, blackish-
vinous; hymenium vinous, 5-10 mm.’ indiam.; asci cylin-
drical, turning blue with iodine, obtuse or truncate,
250-300x12-15 ; sporidia elliptical, pale fuscous, echi-
nate, prominately 1-guttate, monostichous, 15-18x10 y;
paraphyses linear, fuscous above, scarcely incrassate, 3 «
wide.

On damp, shady ground, Otowanie Woods, Lancaster county.

BULGARIACEAE.

Orbilia atropurpurea Clements.
Ascomata superficial, crowded, sessile, gelatinous when wet,
corneous when dry, concave, or applanate, dark purple,
exciple dense, fuscous, 2-5 mm. in diam.; asci elongate,

17

narrowly cylindrical, not turning blue with iodine, 150-
160x8-10 mw: sporidia hyaline, granular, occasionally
spuriously 1-septate, broadly fusoid, somewhat obtuse at
both ends, crowded, monostichous, 20-25x5-6 w; paraphy-
ses filiform, narrow, 1 » wide, abové broadened into a
minute clava.

On dead wood, Hazel Creek Canyon, Brown county.

AGARICACEAE,

Mastocephalus carneo-annulutus Clements.

Pileus campanulate, carnose, exstriate, pellicle incarnate,
densely fibrillose-silky; free ends of the fibrils aggluti-
nated, pileus hence covered with appressed, granular,
atro-incarnate scales; umbo scarcely distinct, slightly de-
pressed, brick-red-incarnate, tomentose, or broken into
minute scales; stipe white, fistulose, shining, silky, in-
crassate at the base, equal above; annulus fixed, superior
or inferior, white, erect, appressed to the stipe; limb ab-
ruptly spreading, beautifully margined with incarnate,
34 mm. wide; lamellae adnexed to a collar, pure white,
slightly crowded; spores hyaline, 1-2-guttate, fusoid-
ellipsoid, strongly apiculate at one end, 10-124x4-5 yp,

Pileus 3 cm. wide, 2 cm. high; stipe 4 cm. long, 5 mm. wide
above, 10 mm. below.

Or shady ground, Otowanie Woods; Wabash, Bellevue.
Related to M. rhodocephalus (Berk) OK.

Mastocephalus incarnatus Clements.

Subcaespitose; pileus thin, slightly carnose, conical, at
length campanulate, rarely convex, slightly silky, pale in-
carnate, with darker scales, margin striate; umbo distinct, .
becoming black; stipe stuffed, slender, equal, glabrous,
very rarely silky, pallid, or somewhat rosy; annulus
median, or superior, fixed, erect, white; lamellae remote,
subdistant, scarcely ventricose, white; spores minute,

18

ovate-ellipsoid, uniguttate, apiculate at one end, 5-6x3 yp.

Pileus 2-4 cm. wide, 14-3 cm. high; stipe 3-6 em. long, 2-
5 mm. thick.

On the ground, among leaves, Wabash, Otowanie Woods.

Mastocephalus repandus Clements.

Pileus convex-repand, carnose, covered with minute, crowded,
granular scales, incarnate-ochraceous; umbo distinct; stipe
graceful, hollow, equal, minutely floccose-farinaceous,
white above, pinkish-ochraceous below; annulus white,
superior; lamellae free, white, ventricose; spores ellipsoid
or globose, 5-7x5

Pileus 13-18 mm. wide; stipe 2-3 em. long, 1-14 mm.

wide.
On rich earth, Lincoln. Related to M. cristatus (Alb. &
Schw.) OK.

Mastocephalus sulphurinus Clements.

Pileus campanulate, then convex, subcarnose, pellicle sul-
phur-yellow, silky, torn into crowded, oblong, or elongate
scales, margin distinctly striate-plicate, floccose; umbo dis-
tinct, elevated, glabrous, or scarcely rimose, incarnate-brick-
colored; stipe graceful, fistulose, pruinose, strongly bulb-
ous at the base, yellow-floccose, above incrassate, shining,
isabel-colored; annulus superior, fixed, laerate, sulphur-
yellow; lamellae, touching the collar, linear, crowded,
nearly white, or pale straw-colored; spores ovate-éllipsoid,
uniguttate, 7-9x4-5 yu.

Pileus 14-3 cm. wide; stipe 4 cm. long, 3-4 mm. wide above,
6-7 mm. below.

On the ground, Lincoln.

_ Clitocybe megalospora Clements.

Pileus plano-convex, subcarnose, even, glabrous, yellow-
orchraceous, darker at the center. margin thin; stipe
graceful, fistulose, glabrous, becoming white; lamellae
white, distant, short-decurrent, pale yellow; spores large,

19

hyaline, with a large oil drop 10 »% in diam., ovoid, or
slightly limoniform, 17-18x10-12 p.

Pileus 3 cm. wide; stipe 7 cm. long, 2 mm. thick.

On wet earth, Saltillo.

Collybia discipes Clements.

Pileus -convex, at length explanate, subcarnose, even, glab_
‘rous, striate at the margin, grayish-drab; umbo wide,
darker, grayish-brown; stipe cartilaginous, stuffed, glab-
rous, shining, white, arising from a hypogaeous disk;
lamellae free, remote, crowded, ventricose, 4-6 wide, pale
orchraceous; cystidia exactly cyathiform or sometimes
flask-shaped, 2-3 cuspidate at the apex, 45-53 y long, 20 p
wide at the base, 10 y at the apex; spores ellipsoid, or ovate,
granular within, 5-6x3-4 yp.

Pileus 5 cm. wide; stipe 34 em long, 5 mm. wide.

On damp ground, Beatrice.

Collybia umbrina Clements.

Pileus convex, carnose, umbonate, brown, glabrous, exstri-
ate, very viscid, dotted with thin, black lines; umbo black;
stipe very long, attenuate above, carnose, stuffed, glabrous,
longitudinally striate towards the apex, radicate, white,
becoming fuscous below; lamellae adnate, broad, distant,
unequal, white; spores large, irregularly limoniform, with
large oil-drop 10 yw in diam., 12-13x17-18 yp.

Pileus 4 cm. wide; stipe 25 cm. long, 5 mm. wide above, 10
mm. below. :

On decaying twigs buried in the ground, Bellevue. Perhaps
but a variety of C. radicata Rehl.

Collybia velutina Clements.
ileus convex, or plane, carnose-cartilaginous, even, covered
with a dense, brown-fulvous tomentum, reddish-chestnut-
colored; stipe fistulose, cartilaginous, equal, densely
clothed with a silky, fulvous-ochraceous tomentum; lamel-

20

lae adnexed, narrow, unequal, crowded, ochraceous; spores
ellipsoid, 7-8x5 p.
Pileus 1-3 em. wide; stipe 3-5 em. long, 14-3 mm. -thick.
On decaying logs, Bellevue.
Lactarius villosus Clements.

Pileus at first convex, margin involute, beset with the fibrils
of the veil, then explanate-umbilicate, rarely infundibuli-
form, spongy-carnose, often irregular, silky-villose, with
long, innate, agglutinated fibrils, disk often minutely to-
mentose-areolate, at first white, then strongly tinged with
orange; stipe short, thick, often excentric, attenuated
downwards, solid, tomentose, white; lamellae adnexed,
decurrent when the pileus is infundibuliform, linear, very
crowded, white, then tinged with ochracrous; milk co-
pious, very pungent, white, immutable; spores irregularly
ellipsoid, or ovoid, uniguttate, echinulate, 5-6x4-5 yp;
cystidia numerous, rugose, lanceolate, 25-30x5 yp.

Pileus 6-12 cm. wide; stipe 14-24 cm. long and thick.

On sandy ground, Hazel Creek Canyons, Brown county.

Warasmius albo-marginatus Clements.
Pileus minute, solitary, membranaceous, convex, glabrous,

sulcate, purple, paler at the margin; stipe shining, glab-
rous, equal, lemon-yellow; lamellae few, ‘7-8, adnate,
white; basidia 12-14x6-7 y; spores (?) 5x2-3 yp, ovoid.

Pileus 14 mm. wide; stipe 1 em. long, 4mm. thick.

On the ground in shady woods, Beatrice.

Marasmius fulviceps Clements.

Pileus convex-campanulate, then convex, or almost applanate,
membranaceous, strongly radiate-sulcate, rugose, glab-
rous, umbonate, fulvo-ferruginous; stipe graceful, with a
medulla, flexuose, spirally twisted above, entirely smooth,
shining, dark-brown, paler at the apex; lamellae adnexed
to a collar around the stipe, with connecting veins, dis-
tant, 15-20, edge flexuous, dark-ochroleucous; spores
hyaline, fusoid, 18-20x5 p.

21

Pileus 5-15 mm. wide; stipe 4-6 cm. long, 4-1 mm. thick.
On dead leaves, Bellevue. Related to Mf. schweinfurthianus
P. Henn.

Marasmius hirtipes Clements.

Pileus plano-convex, membranaceous, scarcely umbilicate,
slightly radiate-suleate, glabrous, fulvous; stipe elongated,
filiform, hollow, clothed with spreading, white or fulvous
hairs, dark-rufous; lamellae somewhat numerous, adnate,
linear, white, or dilutely yellow; spores ellipsoid, minutely:
2-guttulate, 7x4 .

Pileus 3-7 mm.; stipe 83-8 cm. long, 4-3 mm. thick.

Marasmius papillosus Clements.

Pileus conico-papillate, then campanulate, or even explanate,
membranaceous, striate, glabrous, cream-colored, or och-
raceous; stipe graceful, equal, cartilaginous, pruinose
above, densely lanate below, dirty-white, or cream-colored;
lamellae few, adnexed, white; spores ellipsoid, 6x4 p.

Pileus 2-6 mm. wide; stipe 14-3 cm. long, 4-1 mm. thick.

On decaying logs, Beatrice.

Orcella depressa Clements.

Pileus plano-convex, or depressed in the center, sub-mem-
branaceous, glabrous, even, ochraceous, centre darker;
stipe short, solid, glabrous, white, incrassate toward either
end; lamellae decurrent, subdistant, light cinnamon-
colored; spores irregularly ellipsoid, pale rosy, 8—10x4-5 pz.

Pileus 2-14 cm. wide; stipe 14-24 cm. long, 2 mm. thick.

On fallen leaves, Bellevue.

Nolanea atro-cyanea Clements.

Pileus membranaceous, campanulate, glabrous, or minutely
verrucose, papillate-umbonate, striate-lacerate at the mar-
gin, prussian blue; stipe graceful, equal, cartilaginous,
glabrous, bright blue, or slightly tinged with sea-green;
lamellae receding slightly, narrow, subdistant, cream-

22

colored; spores globose, or ellipsoid, 3—7-angular or apic-
ulate, uniguttate, rosy, 5—7x7-9 p.

Pileus 1-3 mm. wide; stipe 1 cm. long, 4-1 mm. thick.

On the ground in woods, Bellevue.

Under the Rochester Rules, Nolanea Fr. seems to be avail-
able, notwithstanding the prior Nolana L.

Hebeloma flavum Clements.

Pileus persistently campanulate, fleshy, viscid, covered with
nearly concentric, fulvous, scales 2 mm. wide, margin in-
curved, appendiculate, bright yellow; stipe thick, solid,
short, curved, densely beset with concentric, floccose, ful-
vous scales, except at the base, yellow; lamellae sub-
sinuate, with a decurrent tooth, slightly crowded, drab;
spores ovoid, ochroleucous, 7—8x4 yp.

Pileus 5-6 cm. wide; stipe 3-5 cm. long, 3-2 em. thick.

On ground, Bellevue.

Galera pulchra Clements.

Pileus conical, broad, membranaceous, striate-sulcate to the
middle, minutely and densely silky-tomentose; umbo dis-
tinct, ochraceous, cream-colored; stipe elongated, cartilagi-
nous, graceful, attenuate, fistulose, characteristically longi-
tudinally lineate striate-pruinose, cream-colored; lamellae
adnexed, narrow, linear, slightly crowded, ochraceous,
spores sublimoniform, fulvous, eguttate, 15—-16x9-10 yp.

Pileus 24 cm. wide, 2 cm. high; stipe 7-8 cm. long, 2 mm.
thick.

On rich, wet ground, Otowanie Woods.

Gomphos caesius Clements.

Pileus at first campanulate-convex, then explanate, carnose,
even, glabrous, not viscid, or obsoletely so, margin invo-
lute, dark eye-blue-violet, at length spotted with brown;
flesh eye-blue, immutable; stipe fibrous-carnose, solid,
with an exactly turbinate bulb, which in age becomes
nearly globose, margin of bulb and base of stipe violet,

23

stipe violet above, ochroleucous below, with a false annu-
lus composed of the fulvous fibrils of the cortina just
beneath the apex; cortina cobwebby, pale eye-blue; lam-
ellae adnate, with a decurrent tooth subdistant, at first
white, then cinnamon-colored, never violet; spores
brownish-fulvous, verrucose, subelliptical, or globose, 8—
10x7-8 yp.

Pileus 4-8 cm. wide; stipe 1-5 em. long, 1-14 em. thick;
bulb 3-4 em. high, 4 cm. wide.

On ground in woods, bluffs of the Missouri river, Bellevue.
Related to G. glaucopus (Schaff.) OK.

Clarkeinda plana Clements.

Pileus carnose, applanate, exactly plane, even, glabrous,
ochraceous, or slightly fulvous; stipe short, stout, solid,
attenuate above, fibrillose-aquamulose, becoming fulvous;
volva ample, adpressed, membranaceous; lamellae free,
ventricose, crowded, black-cinnamon-colored; spores short-
ellipsoid, or globose, uniguttate, purple-fulvous, 4—-6x
5-6 py.

Pileus 7 cm. wide; stipe 3 cm. high, 2 em. thick.

On manured ground, Meadville, Keya Paha county.

Gymnochilus nom. nov.

Psathyra Fr. (1821), not Psathura Commerson, Juss. Gen.
(1789).

Gymnochilus roseolus Clements.

Pileus hemispherical or convex, membranaceous, glabrous,
or minutely micaceous, irregular regulose, vinous when
wet, incarnate when dry; stipe tall, fragile, fistulose, shin-
ing, glabrous, apex beset with a few large, farinaceous
granules; lamellae slightly remote, purplish-cinnamon-
colored; spores ellipsoid, dark-purple, 12-13x7-8 y.

Pileus 1-24 cm. wide; stipe 4—8 cm. long, 2 mm. thick.

On ground, bluffs of the Missouri river, Bellevue.

24

ADDITIONS TO THE REPORTED FLORA OF THE
STATE.
[* Indicates new host only.]
PHYTOMYXINEAE.

* Phytomyxa leguminosarum (Frank) Schroet.
On Astragalus carolinianus, Bellevue. (4251)
On Cassia chamaecrista, Bellevue. (4247)
On Meibomia grandiflora, Bellevue. (4248)

NOSTOCACEAE.

Nodularia paludosa Wolle.
In Salt Lake, Lincoln. (4501)

PALMELLACEAE,

Haematococcus lacustris (Girod) Rost.
On horse droppings, Lincoln (4499), in irrigation ditch,
Rock Creek, Keya Paha county. (4500)

DESMIDIACEAE.

Disphinctium notabile (Breb.) Hansg.
Glen Rock. (4502)

BACILLARIACEAE,

* Amphiprora conspicua Grey.
Lincoln. (4587)
Amphora ovalis Kuetz.
Plattsmouth. (4588)
Amphora ovalis affinis (Kuetz.) V. H.

Lincoln. (4589)
Amphora ovalis gracilis (Ehr.) V. H.

Talmage; fossil, Mullen. (4590)
Amphora ovalis pediculus (Kuetz.) V. H.
Peru, Salem, Fairbury, Humboidt, Bellevue, Auburn, Platts-
mouth, Sheridan county; Weeping Water. (4591)

25

Amphora salina borealis (Kuetz.) Elmore.
Amphora borealis Kuetz. Bacill. 108. (1844)
Amphora salina minor V. H. Syn 57. (1880)
Fairbury. (4592.)
Bacillaria paradoxa (Gmel.) Grun. Crete. (4759)
Campylodiscus campylodiscus (Ehr.) Elmore..
Surirella campylodiscus Ehr. Verb. 424. (1843)
Campylodiscus ehrenbergii Ralfs, Pritchard Inf. 802. (1861)
Talmage, Fairbury, Brock, Lincoln, Auburn, Arago, Brown-
ville, Weeping Water, Ashland. (4593)
‘Cocconeis placentula Ehr.
Holt county, Bellevue; fossil, Mullen. (4594)

Cyclotella meneghiniana Kuetz.
Lincoln, Weeping Water, Talmage. (4595)
Cymbella fusidiwm (Ehr.) Elmore.
Cocconema fusidium Ehr. Inf. 26. (1838)
Cymbella affinis Kuetz. Bacill. 80. (1844)
Humboldt. (4596)

Cymbella cuspidata Kuetz.
Bellevue; fossil, Mullen. (4597)

Cymbella inequalis (Ehr.) Elmore.
Navicula inequatis Ehr. Inf. 184. (1838)
Cymbella ehrenbergii Kuetz. Bacill. 79. (1844)
Holt county, Weeping Water, Talmage; fossil, Mullen.
(4598 )
Cymbella levis Naeg.
Fossil, Mullen. (4599)
Cymbella cistula (Hempr.) Kirchn.
Fossil, Mullen. (4600)
Cystopleura gibba ventricosa (Kuetz.) Grun.
Rulo, Georgetown, Peru, Arago, Humboldt, Tecumseh,
Bellevue, Plattsmouth, Cherry county, Holt county.
(4601)

26

Cystopleura gibberula (Ehr.) Kuntze.
Talmage. (4602)

Cystopleura musculus constricta (Breb.) V. H.
Sheridan county. (4603)
Cystopleura turgida verlagus (Kuetz.) Grun.
Fossil, central Nebraska. (4604)
Cystopleura turgida westermannii (Ebr.) Grun.
Fossil, central Nebraska. (4605)
Denticula elegans Kuetz.
Fossil, Mullen. (4606)
Diatoma vulgare Bory.
Fossil, central Nebraska. (4607)
Encyonema caespitosum auerswaldii (Rabenh.) V. H.
Fossil, Mullen. (4608)
Encyonema prostratum (Berk.) Ralfs.
Fairbury. (4609)
Eunotia formica Ehr.
Fossil, Mullen. (4610)
Fragilaria consiruens venter Grun
Fossil, central Nebraska, Mullen. (4611)
Fragilaria elliptica Schum.
Fossil, central Nebraska, Mullen. (4612)
Fragilaria virescens Ralfs.
Fossil, Mullen. (4613)
Frustulia bohemica (Ehr.) Rabenh.
Sheridan and Cherry counties. (4614)
Gomphonema acuminatum Ebr.
Bellevue. (4615)
Gomphonema gracile Ehr.
Fossil, Mullen. (4616)
Gomphonema micropus Kuetz.
Lincoln. (4617)
Gomphonema montanum Schum.
Auburn, fossil, contral Nebraska, (4618)

27

Gomphonema montanum commutatum Grun.
Talmage, Weeping Water. (4619)
Gomphonema montanum subclavatum Grun.
Bratton, Talmage; fossil, Mullen. (4620)
Gomponema rostellatum lanceolatum V. H.
Talmage. (4621)
Gomphonema turris Ebr.
Talmage. (4622)
Hantzschia amphioxys (Ehr.) Grun.
Lincoln, Talmage, Weeping Water, Sheridan, Cherry aad
Holt counties; fossil Mullen, central Nebraska. (4623),
Hantzschia elongata (Hantzsch) Grun.
Talmage, Holt county; fossil, Mullen. (4624)
Homoeocladia filiformis W. Sm.
Fairbury. (4625)
Melosira distans (Ehr.) Kuetz.
Bellevue; fossil, central Nebraska, Mullen. (4626)
Navicula ambigua Ebr.
Talmage, Tecumseh, Humboldt, Brownville, Weeping Water
Sheridan county. (4627)
Navicula atomoides Grun.
Falls City, Talmage, Fairbury, Humboldt, Bellvue, Auburn
(4628 )
Navicula atomis (Kuetz.) Grun.
Humboldt, Talmage, Peru. (4629)
Navicula bacilliformis Grun.
Fossil, Mullen. (4630)
Navicula bahusiensis Grun.
Fairbury. (46381)
Nawicula cocconetformis Greg.
Humboldt. (4632)
Navicula cryptocephala veneta (Kuetz.) Rabenh.
Brock, Talmage, Peru, Pawnee City, Humboldt, Julian
Falls City, Rulo, Dawson, Salem, Aspinwall, Fairbury,
Tecumseh, Auburn, Weeping Water, Ashland. (4633)

28

Navicula cuspidata Kuetz.
Lincoln, Talmage. (4634)
Navicula decurrens Kuetz.
Talmage. (4635)
Navicula dicephala hr.
Fairbury. (4636)
Navicula digitato-radiata cyprinus (W. Sm.) V. H.
Talmage. (4637)
Navicula elliptica minutissima Grun.
Talmage. (4638)
Navicula falaisensis Grun.
Fairbury. (4639)
Navicula fasciata Lagerst.
Talmage. (4640)
Navicula inflata Kuetz.
Lincoln, Fairbury. (4642)
Navicula iridis Ehr.
Auburn; fossil, central Nebraska. (4643)
Navicula iridis affinis (Ehr.) V. H.
Talmage, Auburn; fossil, Mullen. (4644)
Navicula iridis amphigomphus (Ehr.) V. H.
Fossil, central Nebraska, Mullen. (4645)
Navicula iridis dubia (Ehr.) V. H.
Lincoln, Talmage. (4647)
Navicula levissima Kuetz.
Sheridan county. (4646)
Navicula liburnica Grun.
Lincoln. (4648)
Navicula limosa Kuetz.
Cook, Talmage. (4649)
Navicula macilenta Ebr. Inf. 183. 1838.
Navicula oblonga Kuetz. Bacill. 97. 1844.
Talmage; fossil, central Nebraska, Mullen. ( 4650)
Navicula mesolepta Ehr.
Lincoln, Auburn, (4651)

29

Navicula mesolepta therones (Ehr.) V. H.
Talmage. (4652)
Navicula mutica goeppertiana (Bleisch) Cl. & Grun.
Talmage, Rulo. (4653)
Navicula parallelistriata Pant.
Fossil, Mullen. (4654)
Navicula parva (Ehr.) Elmore.
Stauroptera parva Ehr. Verb 135. 1843.
Navicula stawroptera Grun. Wien Verhandl. 1860:516. 1860:
Fossil, Mullen, (4655)
Navicula parva parva (Grun.) Elmore.
Navicula stauroptera parva Gran.
Talmage, Julian, Arago. (4656)
Navicula peregrina (Ehr.) Kuetz.

Lincoln. (4657)
Navicula placentula (Ehr.) Kuetz.

Fossil, Mullen. (4658)
Navicula placentula tumida (W. Sm.) Elmore.
Navicula tumida W. Sm. Brit. Diat. 1:52. 1853.
Navicula anglica Ralfs, Pritch. Inf. 900. 1861.
Fossil, Mullen. (4659)
Navicula pupula Kuetz.
Nebraska City, Talmage; fossil, central Nebraska, Mullen.
(4660)
Navicula pygmaea Kuetz.
Talmage, Salem, Humboldt, Weeping Water. (4661)
Navicula radiosa Kuetz.
Bellevue. (4662)
Navicula rhyncocephala amphiceros (Kuetz.) Grun.
Talmage, Humboldt. (4663)
Navicula rostrata Ebr.
Talmage; fossil, central Nebraska, (4664)
Navicula saugerii Des.

Salem. (4665)

30

Navicula subcapitata paucistriata V. H.
Bellevue. (4666)
Naviciula viridis commutata Grun.
Lincoln. (4667)
Navicula viridis sublinearis Grun.
Auburn. (4668)
Nitzschia acicularis (Kuetz.) W. Sm.
Julian, Rulo, Lincoln, Salem, Fairbury, Humboldt, Talmage,

Arago, Weeping Water, Ashland, Cherry county. (4669)

Nilzschia amphibia Grun.

Talmage, St. Deroin, Fairbury, Humboldt, Auburn, Weep-

ing Water, Ashland; fossil, Mullen. (4670)

Nitzschia communis obtusa Grun.

Lincoln (4671)
Nitzschia debilis (Arnott & Ryl.) Grun.

Talmage, Brownville, Weeping Water, Lincoln (4672)
Nitzschia fasciculata Grun.

Auburn. (4673)
Nitzschia frauenfeldii Grun.

Lincoln, Weeping Water. (4674)
Nitzschia frustulum (Kuetz.) Grun.

Salem, Holt county. (4675)
Nitzschia hungarica Grun.

Lincoln, Salem, Auburn, Talmage, Fairbury. (4676)
Nitzschia intermedia Hantzsch.

Dawsons, Salem, Peru. (4677)
Nitzschia lanceolata W. Sm.

Lincoln. (4678)
Nitzschia linearis tenuis (W. Sm.) Grun.

Humboldt, Fairbury, Weeping Water. (4679)
Nitzschia obtusa nana Grun.

Fairbury. (4680)
Nitzschia obtusa scapelliformis Grun.

Talmage. (4681)

31

Nitzschia palea debilis (Kuetz.) Grun.

Holt County. (4682)

Nitzschia palea fonticola Grun.

Talmage, Brock, Tecumseh, Pawnee City, Humboldt, Daw-
son, Aspinwall, St. Deroin, Fairbury, Bellevue, Weeping
Water, Sheridan County, Cherry County. (4683)

Nitzschia palea tenutrostris V. H.
Talmage. (4684)
Nitzschia sigma (Kuetz.) W. Sm.
Sheridan County. Julian, Auburn, Ashland. (4685)
Nitzschia sigma diminuta V. H.
Talmage. (4686)
Nilzschia sigma intercedens Grun.
Talmage. (4687)
Nitzschia sigma lamprocarpa (Ehr.) Elmore.
Navicula lamprocarpa Ehr., Kuetz., Bacill. 22. 1844.
Nitzschid sigma rigida (Kuetz.) Grun., Kasp. Alg. 119. 1878.
Fairbury, Auburn, Lincoln. (4688)
Nitzschia sigma rigidula Grun.
Lincoln. (4689)
Nitzschia sigma subcapitata Rabenh.
Talmage. (4690)
Nitzschia stagnorum Rabenh.
Talmage. (4691)
Nitzschia subtilis (Kuetz.?) Grun.
Arago, Julian, Talmage, Lincoln. (4692)
Nitzschia subtilis paleacea Grun.
Humboldt, Weeping Water, Talmage.
Nitzschia tryblionella Hantzsch.

Fairbury, Lincoln. (4730)

Nitzschia tryblionella levidensis (W. Sm.) Grun.

Talmage, Nemaha City, Cherry county, Auburn, Weeping
Water, Lincoln, (4700)

Nitzschia tryblionella salinarwm Grun.

82

Fairbury. (4712)
Nilzschia vitrea recta (Hantzsch.) V. H.
Arago, Peru. (4729)

Odontidium pinnatum (Ehrb.) Kuetz. Bacil. 44. 1844.
Fragilaria pinnata Ebrb. Verbreit. 127. 1843
Dimeregramma mutabile Pritchard Infus. 790. 1845.
Odontidium mutabile W. Sm. Brit. Diat. 2:17. 1853.

Odontidium pinnatum intermedium (Grun.) Elmore.

Fragilaria mutablis intermedia Grun. Verb. Wien. Zool. Bot-
Ges. 12, pl. 7,79. 1862.
Bellevue. (4701)
Opephora pacifica (Grun.) Petit.
Fossil, Mullen, (4713)
Pleurosigma thuringicum (Kuetz.) Elmore.
Navicula thuringica Kuetz. Bacil. 102. 1844.
Navicula angulata Queck. Pract. Treat. on the Microse. 438-
1848. ‘
Pleurosigma angulatum W. Sm. Ann. Nat. Hist. 1853:7. 1853.

Pleurosigma thuringicum elongatum (W. Sm.) Elmore.
Pleurosiyma elongatum W. Sm Brit. Diat. 1:64 1853.
Pleurosigma angulatum elongatum V. H. Syn. 115. 1880.

Pleurosigma thuringicum elongatum forma fallax Grun.

Lincoln. (4721)

Pleurosigma obscurum W. Sm.

Julian, Ashland, Lincoln. : (4702)

Pleurosigma scalproides Rabenh.

Talmage. (4728)
Pleurosigma spencerii nodiferum Grun.
Talmage, Peru. (4705)

Pseudoeunotia lunaris (Ebr.) Grun.

Peru, Bellevue, Auburn, Talmage; fossil, Mullen. (4720)

Rhotconeis trinodis inflata Schultze.

Auburn, Arago, Talmage, Weeping Water; fossil, Mullen.
(4711)

38

Stauroneis anceps producta Lagerst.
Weeping Water. (4703)
Stauroneis gracilis W. Sm.
Plattsmouth. (4722)
Stauroneis heufleriana Grun.
Holt county. (4710)
Suriraya elegans Ebr.
Holt county. (4709)
Suriraya ovalis Breb.
Talmage, Cherry county. (4727)
Suriraya ovalis minuta (Breb.) V. H.
Talmage, Julian, Salem, Fairbury. (4719)
Suriraya ovalis pinnata (W. Sm.) V. H.
Cook, Auburn, Salem, Fairbury, Arago, Talmage, Weeping
Water. (4714)
Suriraya splendida (Ehr.) Kuetz.
Talmage. (4726)
Synedra affinis Kuetz.
Holt county. (4708)
Synedra affinis delicatula Grun.
Weeping Water. (4723)
Synedra affinis tabulata (Ag.\ V. H.
Lincoln. (4715)
Synedra capitata Ehr.
Bellevue; fossil, central Nebraska, Mullen. (4724)
Synedra famelica minuscula Grun. :
Fossil, central Nebraska, Mullen. (4725)
Synedra radians Kuetz.
Fossil, Mullen. (4706)
Synedra rumpens Kuetz.
Talmage. (4707)
Synedra tenwissima Kuetz. Bacil. 68. 1844.
Synedra acus Kuetz. |. c.
Frustulia tenwissima Kuetz. Syn. Diat. 24. 1834.

84

Synedra tenuissima angustissima (Grun.) Elmore.
Synedra acus angustissima Grun. in V. H. Syn. 151. 1880.
Weeping Water. (4716)
Synedra tenuissima delicatissima (W. Sm.) Elmore.
Synedra delicatissima W. Sm. Brit. Diat. 1:72. 1853.
Synedra acus delicatissima Grun. in VH. Syn. 151. 1880.
Tecumseh, Cherry county. °(4718)
Synedra ulna amphirhynchus (Ehbr.) Grun.
Talmage; fossil, Mullen. (4731)
Synedra ulna danica (Kuetz.) VH.
Fairbury, Holt couuty. (4717)
Synedra ulna oxyrhynchus (Kuetz.) VH.
Fossil, Mullen. (4732)
Synedra ulna vitrea (Bory) VH.
Arago. (4733)
Synedra vaucheriae Kuetz.
Lincoln. (4735)
Tabellaria fenestrata (Lyngb.) Kuetz.
Fossil, Mullen. (4734)

ZYGNEMACEAE.
Spirogyra jugalis (Dillw.) Kuetz.
In ponds, Lincoln. (4504)
MUCORACEAE.

Circinella umbellata Van. Tieg. & Le M. ~
On horse dung, Lincoln, (4495)
Piptocephalis freseniana De Bary & Wor.
On horse dung, with the preceding, Lincoln. (4494)

PERONOSPORACEAE,
*Albugo candida (Pers.) 8. F. Gray.
On Lepidium sativum, Lincoln. (4447)
ULOTRICHIACEAE.

Conferva tenerrima Kuetz..
In tank in the zoological laboratory, Lincoln. (4496)

35

SPHAERIACEAE.

Eutypella scoparia (Ell.) Sace.
On dead twigs of Ulmus, Weeping Water. (4434)
Diaporthe tuberculosa ( Ell.) Sace.
On stems of Amelanchier canadensis, Weeping Water.
(4435)
Diaporthe claviceps Ell. & Tver.
On twigs of Ostrya virginiana, Weeping Water. (4430)
Valsa toici (Schw.) Ell. & Ever.
On dead stems of Rhus radicans, Weeping Water. (4484)
Ohleria modesta Fk.
On decorticated branches of Ulmus, Lincoln. (4433)
Melanomma alpinum Speg.
On decorticated wood of Rhamnus lanceolata, Weeping
Water. (4581)
Sporormia minima Auersw.
On horse dung, Lincoln. (4487)
Massaria conspurcata (Wallr.) Sace.
On dead branches of Prunus americana, Lincoln. (4432)
Massaria vomitoria B. & C.
On fallen twigs of Amelanchier canadensis, Weeping Water.
(4485)
HYPOCREACEAE.

Cordyceps militaris (L.) Lk.
In the larva of a butterfly, Bellevue, (4411)

HYSTERIACEAE,

Hysterium pulicare lenticulare Fr.
On the bark of Ulmus fulva, Lincoln, (4423)
Hysterographium elongatum (Wahlen.) Corda.
On decaying wood of Rhamnus lanceolata, Weeping Water.
(4583)
Hysterographium kansense Ell. & Ever.
On bark of Quercus macrocarpa, Weeping Water. (4429)

36

Hysterographium rousselii (De Not.) Sace.
On decorticated wood, Bellevue. (4422)
Hysterographium syringae (Schw.) Sace.
On dead wood, Brownville. (4497)

UREDINEAE.

Uromyces plumbarius Peck.
On Oenothera biennis, Crete. (4358)
Aecidium allenti Clinton.
On Lepargyraea argentea, Valentine. (4396)
Aecidium anisotomes Reichardt.
On leaves and fruits of Peucedanum foeniculaceum, Weeping
Water. (4395)

SPHAERIOIDEAE.

Phyllosticta gentianicola (DC.) Fr.

On Gentiana andrewsti, Ewing. (4482)
Macrophoma ricint (Cke.) Berl. & Vogl.

On Ricinus communis (dead stalks) Lincoln. (4884)
Cytospora ambiens Sace.

On twigs of Ulnus, Weeping Water. (4583)
Cytosporu ampelopsidis C. Mass.

In stems of Parthenocissus quinquefolius, Lincoln. (4498)
Cytospora cincta Sace.

In twigs of Prunus cerasus, Lincoln. (4450)
Sphaeropsis albescens Ell. & Ever.

On dead twigs of Acer negundo, Lincoln. (4428)
Diplodia maydts (Berk.) Sace.

On old stalks of Zea mays, Weeping Water. (4483)
Chaetomella atra Fekl.

On dead stems of Allionia nyctaginea, Lincoln. (4545)
Septoria chenopodii West.

On Chenopodium album, Valentine. (4449)

If the forms found on Chenopodium album described as

Septoria chenopodu, S. atriplicis, and S. weslendorpit are

37

to be regarded as distinct, the specimens reported should
be referred to S. atriplicis; but there seems to be no
sufficient reason for distinguishing them. See Syl.
Fung. 10: 380, Farlow & Seymour, Host Index 2:89.
If the several forms are united as one species, the name
S. chenopodii has priority.
Septoria helianthi Ell. & Kell.
On leaves of Helianthus annuus, Lincoln. (4369)
Rhabdospora helianthicola (Cke. & Hark.) Sace.
On stems of Helianthus annuus, Lincoln. (4365)

NECTRIOIDEAE.

Cyphina lanuginosa (Peck) Sace.
On dead leaves, Beatrice. (4417)

EXCIPULACEAE.

Dinemasporium graminum Lev.
In stems of Zea mays, Beatrice. (4415)
Dinemasporium strigosum leptosporum Sacc.
On stems of Heliathus, Lincoln. (4399)

MELANCONIEAE.

Gloeosporium tuberculoides Sace.

On dying leaves of Acer saccharinum, McCook. (4454)
Marsonia juglandis (Lib.) Sace.

On Juglans nigra, Saltillo. (4328)

MUCEDINACEAE,

Monilia fumosa Sacc. ?

On decaying seedlings of Cucurbita maxima in the labora-
tory, Lincoln. (4586)

Alysidium fasciculatum (Grev.) Pound & Clements, nom. nov.
Acrospermum fasciculatum Grev. Fl. Edin, 469. 1824
Oidium fasciculatum Berk., Smith’s Engl. Flor. 5 : 849.

1836.

38

Oospora fasciculata Sacc. & Vogl. Sace. Syl. Fung. 4: 11.
1886.

On lemon peel, Lincoln. (4388)

Alysidium Kunze. Myk. Heft. 1: 11, 1817 must be used
instead of Oospora Wallr. Fl. Crypt. Ger. 2 : 182, 18338;
the name adopted by Saccardo. Alysidiwm was founded
for A. fuluum Kunze.=Oospara fulva Sace. & Vogl. 1. «.
Moreover, Bonorden, Handb. 35, 1851, took up Alysidium
and described several species, one a Torula, but the rest
placed in Oospora by Saccardo. Even those who would
oppose a year limit of fifty years to the rule of priority,
must restore the name Alysidium. The saprophytic spe-
cies were generally included with the parasitic ones in
Oidium until 1886, and neither Oospora nor Alysidium
were in general use. But the latter having been adopted
in 1851 by Bonorden cannot be called obsolete. Acros-
permum Nees 1816 was founded on Oidiwm monilioides
and was applied to this genus by Persoon in 1822,

Rhopalomyces elegans Corda. ,
On decaying pericarps and growing seedlings of Beta alba,
Lincoln. (4503)

Sterigmatocystis variabilis (Gasp.) Sace.

On bread, Lincoln. (4506)
Rhinotrichum corticioides Cooke.

On wood, Saltillo. (4309)
Trichothecium sublutescens (Peck) Sace.

On bark of Populus monilifera, Lincoln. (4488)
Jacobuschella alba (Bon.) OK.

On decaying Plewrotus, Lincoln. (4585)

DEMATIAOEAE.

Cladosporium grumosum (Pers.) Lk.

On ferns in greenhouse, Plattsmouth. . (4359)
Cladosporium atrum Lk.

On decaying water-melon rind, Lincoln, (4489)

39

Diplosporium cookei (Sace.) OK.

On rotten wood, Endicott. (4316)
Heterosporium allii sisyrinchii Speg.

On leaves of Iris versicolor, Peru. (4555)
Heterosporium variabile Cooke.

In the sap of living trees of Ulmus fulva, Peru. (4547)
Clasterosporium hirudo Sace.

On decaying wood, Saltillo. (4323)
Septonema atrum Sace.

On dead branches of Ulmus, Weeping Water. (4580)
Septonema toruloideum Cke. & Ell.

On an insect-gall, Franklin, (4319)
Sporoschisma mirabile B. & Br.

On rotten wood, Bellevue. (4315)
Coniothecium effusum Corda.

On decorticated twigs of Populus monilifera, Memphis.

(4577)

Macrosporium caudatum Cke. & Ell.

On leaves of Ficus elastica, Lincoln. (4516)
Macrosporiwm fasciculatwm Cke. & Ell.

On pods of the cultivated bean, Kennedy. (4481)
Macrosporium inquinans Cke. & Ell.

On sun-flower stalks, Lincoln. (4360)
Macrosporium maydis Cke. & Ell.

On leaves of Zea mays, Lincoln. (4404)
Speira toruloides Corda.

On decorticated wood of Rhamnus lanceolata, Weeping

Water. (4582)

Helicosporium vegetum Nees.

On decaying oak twigs, Brownville. (4486)

STILBACEAE.

Shlbum fasciculatum B. & Br.
On Dianthus sinensis, Lincoln. (38321)

40

Isaria candida Schw.

On decaying wood, Ewing. (4517)
Stysanus stemonites (Pers. ) Corda.

On horse-dung in culture jar, Lincoln. (4521)
Graphium stilboideuwm Corda.

On sawdust in culture jar, Lincoln. (4566)

TUBERCULARIACEAE.

Knyaria fatiscens (Schw.) OK.

On twigs of Prunus americana, Wabash. (4264)
Fusarium nucicola Karst. & Har.

On nuts of Juglans nigra, and on acorn cups of Quercus

macrocarpa, Otowanie Woods. (4456)

Fusarium salmonicolor B. & C.

On sunflower stalks, Beatrice. (4325)
Fusarium sarcochroum (Besm.) Sace.

On fruits of Acer saccharinum, Lincoln. (4448)
Fusarium tenuissimum (Peck.) Sace.

On sunflower stalks, Beatrice. (4310)

HELVELLACEAE.

Helvella crispa (Scop.) Fr.
In shady places, Bellevue. (4421)
Helvella elastica Bull.
In sandy canyons, Long Pine. (4407)
Helvella macropus (Pers. ) Karst.
On sandy ground, Hazel Creek Canyons, Brown county.
(4531)
Helvella pezizoides Afz.
On sandy ground, Meadville. (4479)
Geoglossum nigritum Pers.
Canyons of the Niobrara River, Brown county. (4475)
Geoglossum ophioglossoides (L.) Sace.
On shady ground, Bellevue. (4420)

41

PEZIZACEAE.

Peziza atro-vinosa Ger. & Cke.

On rich ground, Meadville, Keya Paha county. (4539)
Peziza badia Pers.

On ground, Weeping Water, Bellevue. (4455)
Peziza sepiatra Cooke. (?)

On wet, decaying wood, Niobrara river. (4555)
Pyronema omphalodes Bull.

On wet, ploughed ground, Lincoln. (4468)
Barlaea constellatio B. & Br.

On ground among mosses, Rock Creek, Keya Paha county,

Bellevue. (4469)

Sarcoscypha floccosa Schw.

On wet, dead twigs, Bellevue, Lincoln. (4543)

Sepultaria cretea (Cooke. ) Clements.
Lachnea cretea Cooke.

On sandy ground, Hazel Creek Canyons, Brown county.
(4548)

Sepultaria livida (Schum.) Clements.
Lachnea livida Schum.

On sandy ground, Hazel Creek canyons, Brown county.
(4458)

Sepultaria setosa (Nees) Clements.
Lachnea setosa Nees.
On wood among mosses, Meadville. (4544)

Sepultaria umbrarum (Fr.) Clements.
Lachnea umbrarum Fr.
On wet ground Otowanie woods. (4556)

Sepultaria umbrata (Fr.) Clements.
Lachnea umbrata Fr.
On wet wood, canyon of the Niobrara river, Brown county.

(4588)

42

Helotium citrinum (Hedw.) Fr.

On wet, decaying wood, Mead’s ranch, Brown county; Rock

creek, Keya Paha county. (4455) (4409)

Helotium conformatum Karst.

On dead wood, Long Pine. (4269)
Helotium parile languidum Karst.

On stems of Helianthus, Wabash. (4263)
Helotium rhizogenum Ell. & Ever.

On corticated branches of Prunus, Bellevue. (4259)
Pseudohelotium hyalinum (Pers.) FkL

On decorticated wood, Wabash. (4270)
Molissia cinerea luteola Sacc.

On decorticated branches of Prunus, Wabash. (4260)

ASCOBOLACEAE.

Ascophanus aurora (Cr.) Boud.
On cow-dung, Wabash. (4478)
Lasiobolus equinus (Mull.) Karst.
On horse-dung, Lincoln. (4401)

DERMATEACEAE.

Cenangium crataegi Schw.

On living branches of Crataegus tomentosa, with the pycni-
dial stage, Sphaeronema longirostre Clements, Saltillo.
(4398)

Cenangium populneum carpini (Rehm) Clements.
Cenangium carpint Rehm.
On corticated wood, Lincoln. (4402)

STICTACEAE,

Propolis faginea (Schrad.) Karst.

On dead stumps of Quercus macrocarpa, Bellevue. (4267)
Stictis mollis Pers.

On fallen twigs, Otowanie woods; Mead’s Ranch. (4418)

43

PATELLARIAOEHAE.,

Hysteropatella elliptica (Fr.) Rehm.

On the bark of Ulmus americana, Lincoln. (4410)
Hysteropatella prostii (Desm.) Rehm.

On decorticated wood, Beatrice. (4556)

AGARICACEAE,

Amanita muscaria L.

On wooded bluffs of the Missouri river, Bellevue. (4230)
Pseudofarinaceus speciosior Batt.

On the ground, Bellevue. (4557)
Mastocephalus cristatus (Alb. & Schw.) OK.

In shaded places, Otowanie woods. (4058)
Tricholoma patulum Fr.

On the ground among dead leaves, Otowanie woods. (4559)
Tricholoma virgatum Fr.

In woods, Bellevue. (4237)
Collybia dryophila Bull.

On decaying leaves and manure, in densely shaded places,

Otowanie woods. (4560)

Collybia radicata Relh.

In shady woods, Wabash. (4561)
Mycena iris Berk.

On the ground among twigs, Otowanie woods. (4562)
Russula emetica Fr.

In shady woods, Bellevue, Lincoln, Milford, Beatrice. (542)
Marasmius coniatus B. & Br. “

Among dead leaves, Wabash. (4465)
Marasmius rotula microcephalus Sace.

On dead trunks and leaves, Wabash. (4256)
Volvaria bombycina (Pers.) Fr.

On a living tree, Lincoln. (4229)
Eccilia tristis Bres.

Among grass in woods, Wabash. (4558)

44

Pholiota gibberosa Fr. ?
In woods, Wabash. (4255) -

Naucoria semiorbicularis Bull.

In grass, University campus, Lincoln. (4999)
Galera bryorum Pers.

On mossy banks, Bellevue. (4234)
Gomphos callisteus (Fr.) OK.

On the ground, Bellevue. (4563)
Stropharia merdaria Fr.

On horse dung, Meadville, Keya Paha county. (5000)
Stropharia stercoraria Fr.

In manured places in woods, Bellevue. (4235)
Gymnochilus flavo-griseus (Berk.) Clements.

Psathyra flavo-grisea Berk.

Among dead leaves, Bellevue. (4236)
Coprinus filiformis B. & Br.

On wet straw in culture-jar, Lincoln. (4564)
Coprinus floccosus (DC.) Fr.

On twigs and ground in woods, Bellevue. (4232)
Coprinus ovatus (Schaeff.) Fr.

On wet earth, Saltillo. (4238)
Panaeolus papilionaceus Fr.

In manured places, Lincoln. (4228)

POLY PORACEAE.

Boletus chrysenteron Fr.
On the ground in shady woods, Bellevue. (5025)
Boletus edulis Bull.
On the ground in woods, Bellevue. (5026)
Boletus subtomentosus L.
In leaf-mould, Otowanie woods. (4565) Pileus olivaceous
when young, brick-red, and densely silky in age; flesh
becoming blue when cut.

45

THELEPHORACEAE.

Peniophora flavido-alba Cooke.
On decaying bark, Lincoln. (4408)

ALISMACEAE.

Sagittaria longiloba Engelm.
Minden. (4505)

LEMNACEAE,

Wolffia brasiliensis Weddell.
Bellevue. (4507)

GRAMINEAE.

Poa refleca Vasey & Scribner.
Norfolk. (4520)
Chamaeraphis verticilluta (L.) Porter.
Washington county. (4508) Fremont. (4523)

CYPERACEAE.

Scirpus pauciflorus Light.

Fremont. (4528)
Fuirena squarrosa Michx.

‘Fremont island, Dodge county. (4509)
Carex granularis Muhl.

Platte river, near Fremont. (4514)
Carex lupulina Muhl.

Fremont. (4510)

CRUCIFERAE.

Cardamine bulbosa (Schreb.) B.S. P.
Fremont. (4515)

Thiaspr arvense L.
Fremont. (4512)

CARYOPHYLLACEAE.

Alsine media L.
Fremont. (4511)

46

CISTACEAE,
Lechea stricta Legett.
Adams county. (4527)

VITACEAE.
Vitis cinerea Engelm.
Peru. (4530)
Ampelopsis cordata Michx.
Peru. (4532)
CHENOPODIACEAE.

Chenopodium urbicum L.
Cherry county. (4513)
AMARANTHACEAE.
Amaranthus torreyi (Gray) Wats.
Thomas county (4524), Hooker county (4535)
Acnida tamariscina dehiscens Uline and Bray.
Lincoln (4518), Wahoo (4534)
ROSACEAE.
Rosa engelmantt Wats.
Sowbelly Canyon, Sioux county. (4526)
PAPILIONACEAE.
Astragalus lotiflorus nebraskensis Bates Am. Nat. 29 : 670,
1895.
Long Pine. (4749) Clay county. (4750)
Astragalus giganteus (Pall.) Sheld.
North Platte. (4751)
Psoralea collina, Rydberg Flor. Nebr. 16 : 54, 1895.
Fort Robinson (Dr. Bessey, 1887), Scott’s Bluff county.
(50)
Kuhnistera candida diffusa, Rydberg Flor. Nebr. 16 : 59, 1895.
Deuel county. (58)
Lathyrus ornatus flavescens, Rydberg Flor. Nebr. 16 : 64, 1895.
Dodge, Kearney, and Cherry counties.
Lathyrus ornatus incanus, Smith & Rydberg, Flor. Nebr. 16:

64, 1895.
Sheridan county (49); Fort Robinson (Dr. Bessey, 1887).

47

GROSSULARIACEAE.

Ribes aureum chrysococcus, Rydberg Flor. Nebr. 16 : 71, 1895.
Scott’s Bluff, Banner, and Cherry counties. (106, 1601)

ONAGRACEAE,

Oenothera fremontii, Wats.
Bloomington. (4737)

Oenothera serrulata spinulata, Torr. & Gr.
Lancaster county. (4519) Fairbury. (4536)

ARALIACEAE.
Panax quinquefolia L.

Bellevue. (4522)

UMBELLIFERAE.
Daucus carota L.

Nebraska City. (4525)
Eryngium yuccaefolium Michx.
Richardson county. (4529)
LOBELIACEAE.
Lobelia cardinalis L.

Franklin. (4739)
CAMPANULACEAE.

Specularia leptocarpa Gr.
Fairbury. (4740)

PRIMULACEAE.
Anagallis arvensis L.
Fairbury. (4738)

ASCLEPIADACEAE,

Ampelanus albidus (Nutt.) Britt.
Auburn. (4533)
POLEMONIACEAE.
Phlox kelseyi Britt.
Sioux county. (4554)

48

BORAGINACEAE,

Cynoglossum officinale L.
Weeping Water. (4537)

Mertensia paniculata (Ait.) Don.
Sheridan county. (4553)

VERBENACEAE.

Verbena stricta x bracteosa.
Fremont. (4538) Kearney. (4552)
Verbena bracteosa x urticifolia.
Tecumseh. (4540)
COMPOSITAE.

Vernonia marginata (Torr.) Britt.
Fremont. (4551)
Vernonia baldwinit Torr.
Bertrand, Phelps county. (4541)
Helianthus hirsutus trachyphyllus Torr. & Gr.
Bellevue. (4550)
Hymenopappus flavescens Gray.
Fairbury. (4542)
Mieracium wmbellatum UL.
Squaw canyon, Sioux county. (4549)

SUMMARY.
Previously 16 ported. (3.155 Gs whys aed gaearae Kea wines
In this report: '
INGW SpOClesys wise Soaks eucua ate gba bet Seas 55
Other additions ¢ yvcea raw ce awe sees aye ele eed on sn wes 323
Wotal iss seca ar ag Meee ae week Ts Gbvewe dane 378
Less new hosts only.... 02... . cee cee eee eee 2

=

UNIVERSITY OF NEBRASKA
BOTANICAL SURVEY OF NEBRASKA

Conducted by the Botanical S

V.

Report on Recent Collections

Studies in the Vegetation of the State, T.

SEEN

LINCOLN, NEBRASKA
PUBLISHED BY THE SEMINAR
1901
(Distributed March 30, 1901)

base ———— dae

=a
—_— Iw

»

REPORT

ON

RECENT COLLECTIONS

STUDIES

IN THE

VEGETATION OF THE STATE, I.

dacob North & Co., General Printers, Lincoln

TABLE OF CONTENTS

NOLOGY asses iasediens Sassen E Saad aor: Ha eaten 4
Report on Recent Collections. ............. 20000 ee eee 5
New Species of Fungi............ 0... cece eee eee eee 5
Additions to the Reported Flora of the State........... 12
The Prairie-grass Formation in Region I............... 29

Introduction eich eee ke eee wage ea eae yes 29
Discussion of Ecological Factors. ............. 000s eee 32
Ecological Factors.......... ce cee cee ee cee eee eens 38

Temperature and Atmosphere...............--+-0-- 38

Water-content voi soe accecag agate souadeawe eae wees 43

Light Intensity. ......... 0... cece eee ene eee 46
Enumeration of Species in the Formation............. 51
Structure of the Formation..................... 0008) 54
Elements of the Prevernal Floral Aspect............... 57
Elements of the Early Vernal Floral Aspect........... 60
Elements of the Late Vernal Floral Aspect............ 66
Elements of the Early Estival Floral Aspect............ 71
Elements of the Late Estival Floral Aspect........... 81
Elements of the Serotinal and Floral Aspect........... 86
Quadrat: LIStSieec sigs vst eos esas Ria ald aed We VAS ose OER 95
Legend, sacisew caine saa ewe Ales 4s ERs Ree a wis 126
Map of the Formation............. 0.0... cece eee opp. 126
Quad rat: Maps joi ais ena acawda pe ote elke B56 Cae Se gia eR En 127

Phenologi¢al Reé@ord..< ss ciessavssseassesncseesas caus 187

NOTE

The necessary precursor of all phytogeographical investi-
gation is accurate and thorough acquaintance with the flora
of the territory in question. Hence the reports of the Survey
hitherto have been devoted chiefly to bare lists of additions
and the results of collections in the various parts of the
State. Much that has been published in this way stands
in need of revision, and the catalogue of species, now ten
years old, requires complete overhauling, in the light of the
subsequent development of the science and of more com-
plete data as to the distributional boundaries of species. If
the Seminar can command the means therefor, it is hoped
that a descriptive catalogue of the flora of the State may
be issued soon as one of the publications of the Survey. But
all this work is preliminary to the study of the vegetation, the
foundation of which has been laid during the past sixteen
years; and study of the vegetation as such has been looked
forward to as the ultimate purpose of the Survey.

Under the direction of the Seminar, Mr. J. J. Thornber
has been engaged for some years past in the investigation
of the prairie-grass formation in the best known and most
accessible region of the State. The results of his work are
given chief place in this report.

In the list of additions to the reported flora, Messrs. Pound
and Clements have identified the fungi, Mr. C. J. Elmore
the diatoms, and Messrs. J. L. Sheldon, G. G. Hedgecock, and
A. A. Hunter have assisted in various groups. The thanks
ef the Seminar are due to Rev. J. M. Bates and to Messrs.
M. E. Moore, of Springview, and J. P. Anderson, of Lamoni,
Towa, for collections. Above all, however, the Seminar is
indebted to Mr. G. W. Holdrege, without whose generous
assistance adequate investigation in an area as extensive as
Nebraska would have been impossible.

CHARLES E. BESSEY,

Roscor Pounp,

Freperic E. CLEMENTS,
March 12, 1901. Editorial Committee.

NEW SPECIES OF FUNGI

All color-terms used below conform to the charts and syn-
onymic lists in Saccardo’s Chromotaxia.

SPORODESMIACEAE

Septonema isthmiuwm Pound and Clements.

Caespituli thin, broadly effused, very dark; sporophore
obsolete; chains of conidia simple, 90-150 » long, very
often with a hyaline, simple or 1—2-septate terminal
conidium, conidia sooty brown, clavate-cylindrical,
strcight, or rarely slightly curved, 3-7-septate, con-
stricted at the partitions, connected by a short, nar-
row isthmus 3-4 » wide, cells with a single large
gutta, 35-70x10z.

On dead twigs of Smilax hispida, Wabash. (4597)

EXCIPULACEAE

Scaphidium Clements nov. gen.

Apopycnidium oblong or linear- -disciform, at length
hysterioid, waxy-membranaceous, dark brown; basidia
simple; sporidia uniseptate, hyaline, fusoid. Cor-
responds to Sporonema in the Hyalodidymae.

Scaphidium boutelouae Clements.

Apopycnidia minute, grouped in lines, upon indistinct
brownish spots, innate-erumpent, dark brown, mem-
branaceous, or waxy-membranaceous, linear, hyster-
ioid, glabrous, 100 » in diameter; basidia simple,
very short, hyaline, 10x2 »; sporidia hyaline, solitary,
uniseptate, sigmatoid, 25x34 pz.

On leaves of Bouteloua hirsuta, Simeon. (12100)

a

6 REPORT ON RECENT COLLECTIONS
HYPODERMIACEAE

Graphyllium Clements nov. gen.

Hysterothecium innate, then erumpent, linear, simple,
membranaceous-plectenchymatous, black; asci ovoid
or cylindrical-clavate, 8-spored; spores brown, ellipti-
cal to oblong, with transverse and longitudinal septa,
but not muriform; paraphyses simple or branched,
septate, forming an epithecium.

Graphyllium chloes Clements.

Hysterothecia minute, sparse or gregarious, sometimes
lineate, innate, at length erumpent, glabrous, elon-
gate-elliptical or linear, membranaceous, composed of
irregularly polygonal cells, 5x6 », lips thin, gaping
at maturity, black, 30-50 » wide by 100-300 » long;
asci 8-spored, of two forms, ovoid-clavate, 60x15 », or
cylindrical-clavate, 90-110x12 », stipitate, not blue
with iodin; paraphyses few, septate, simple or ramose,
hyaline, globose above, 2-3 » wide; spores distichous
or irregularly monostichous, brown or yellow-brown,
oblong or ovate-oblong, obtusely rounded at the ends,
3-, very rarely 4-, septate, at maturity the two mid-
dle loculi divided longitudinally, the others also
sometimes, smooth, somewhat compressed, distinctly
constricted at the septa, tre second loculus usually
inflated, 20-22x8-10 ».

On stems of Aristida purpurea and Bouteloua oligosta-
chya, Long Pine. (12101)

PEZIZACEAE

Peziza (Plicaria) elaeodes Clements.

Ascoma small, sessile, convexo-explanate, the margin
elevated, thick, smooth, olivaceous within and with-
out, 1-13 cm. wide; asci 8-spored, cylindrical, scarcely
stipitate, filled below with a dense, olivaceous pro-
toplasm, blue with iodin, 250x15_; paraphyses

NEW SPECIES OF FUNGI a

broadly linear, slightly clavulate, nearly colorless;
spores ellipsoid, asperate, becoming olivaceous, apic-
ulate both ways, 25x10 p.

On twigs of Juniperus scopulorum, Mead’s spring,
Brown county. (12102)

Peziza (Plicaria) roseo-lilacina Clements.

Ascoma sessile, waxy-carnose, persistently concave-
cupuliform, smooth, ochroleucous, margin often ir-
regularly lobed, hymenium rose-lilac, 1-14 cm. wide;
asci 8-spored, cylindrical, apex light blue with iodin,
300x15 »; paraphyses linear, scarcely incrassate above,
densely filled with lilac granules, apex 6-7 »; spores
monostichous, ovoid-ellipsoid, smooth, 1—2-guttate,
17-18x10 p.

On wet sandy ground among mosses, Barney creek,
Kkeya Paha county. (12103)

Humaria silvosa Clements.

Ascoma minute, sessile, sparse or gregarious, at first
hemispherical, closed, then open, margined, entire,
concave, saffron-luteous, }-1 mm. wide; asci 4-spored,
irregular, stipitate, truncate above, inoperculate, blue
with iodin, 150x18 »; paraphyses linear, long-clavate,
clava 30x7-8 », simple, filled with large pale luteous
granules, 5 » wide; spores ellipsoid, obtuse both ways,
straight or obliquely monostichous, with 2-3 large
guttae, 25x12 p.

On wet mossy banks, Dry Branch, Humboldt. (12104)

Pelodiscus Clements nov. gen.

Ascoma minute, superficial, sessile, carnose, cupulate,
at length disciform or explanate, pilose without, but
not ciliate at the margin; asci cylindrical, 4—8-spored,
paraphysate; spores ellipsoid or oblong, hyaline.

Pelodiscus agrees with Humaria and Scutellinia in hay-
ing the ascoma superficial, while in Sepultaria and in
Sarcosphaera it is at first hypogaeous. It agrees with
Sepultaria in being simply tomentose or lanose with-

8 REPORT ON RECENT COLLECTIONS

out, in which it differs from the smooth Humaria and
the ciliate-tomentose Scutellinia.
Pelodiscus miniatus Clements.

Ascoma carnose, single, or in groups of two or three,
miniate, margin naked, sparsely clothed without, the
base excepted, with very short, continuous, flexuous,
pale dark yellow pila, 70-80x10 », hymenium concave
or plane, exactly circular, miniate, 1-2 mm. wide,
4-1 mm. high; asci 8-spored, clavate, not blue with
iodin, 250x15 »; paraphyses septate, with a large red-
orange clava, 9-12 », filled with a red protoplasm
which turns a deep blue with iodin; spores straight or
obliquely monostichous, elliptical, four often some-
what abortive and diverse, beautifully papillate, the
papillae 2-3 » high, hyaline, 26-28x12-14 p.

On stercorate mud, Beal’s slough, Otowanie woods.
(12105)

Pelodiscus piliseta Clements.

Ascoma carnose, applanate, rarely concave, margin en-
tire, naked, luteo-fulvous, pila pointed, strict, sparse,
brown, 2-3-septate, attenuate at the base, 300-400x25
#, hymenium bright luteo-fulvous, 1 cm. wide; asci
8-spored, cylindrical, not blue with iodin, 250x25 x;
paraphyses septate, clavate, 4-5 », clava 8 » wide,
nearly colorless; spores large, broadly elliptical,
densely filled with polygonal granules, indistinctly
crenulate or verrucose, obliquely monostichous, 30x
16-18 p.

On wet wood, Barney creek, Keya Paha county.
(12106)

Sepultaria gigantea Clements

Ascoma cupulate-hemispherical, 3-8 cm. wide and high,
hypogaeous, gregarious, opening widely, subcoriace-
ous, margin contorted, entire, strongly lacunose at
base, brown-ochraceous, densely clothed with septate,
flexuous, fuligineous pila, 250-700x17 », hymenium

NEW SPECIES OF FUNGI 9

ochroleucous; asci 8-spored, elongate, stipitate, not
blue with iodin, 350x15 »; paraphyses linear, apex
fuscescent, scarcely incrassate, 7 » wide; spores
straight or obliquely monostichous, fusoid-elliptical,
bi- or multi-guttate, strongly tuberculate, 30-35x
13-15 pb.

In rich soil beneath leaves, Otowanie woods. (12107)

ASCOBOLACEAE

Ascobolus stercorarius retispora Clements.

Ascoma at first luteo-olivaceous, then brown, plane,
limicolous; margin none; spore densely and minutely
reticulate, elongate-elliptical 12—13x20-22..

Related to Ascobolus stercorarius nudus (Kickx) Boud.

On stercorate mud, Otowanie woods. (12108)

Ascophanus isabellinus Clements.

Ascoma humicolous, carnose, at first nearly doliiform,
then convex or explanate, naked, white, then isabel-
colored, 1-3 mm.; asci broad, 8-spored, stipitate, blue
with iodin, 250x30-40 »; paraphyses of two sorts,
linear, much exceeding the asci, and clavate, only
slightly longer than the asci, 3 » wide; spores dis-
tichous, elliptical, hyaline, smooth, with a thick,
lamellose wall 2-34 » wide, 27-30x12-13 z.

On stercorate mud, Otowanie woods. (12109)

AGARICACEAE

Volvaria concinna Clements.

Pileus submembranaceous, expanded, not at all or only
slightly umbonate, smooth, pale avellaneous, 4-14 cm.
wide; stipe graceful, concolorous, 1-2 mm. x 4-1}
cm.; volva minute, strictly adpressed, limb obso-
lescent; lamellae free, rose-colored; spores ovate-el-
lipsoid, granular or guttate, smooth, rosy, 8-11x5-7 yp;
cystidia lacking.

10 REPORT ON RECENT COLLECTIONS

On moist shaded ground and on flooded banks, Nemaha
river, Humboldt, 1897; Marysville, Kansas, 1896.
(12110)

Volvaria submyochrous Clements.

Pileus subcarnose, convex, almost plane, scarcely um-
bonate, silky, shining, umbo densely covered with
larger silky fibrils, becoming innate toward the
strongly striate margin, pale avellaneo-murinous, 3-4
cm. wide; stipe carnose, equal, solid, white, shining,
farinose at the apex, 5 mm.x 3-4 cm.; volva small,
hirsute, 2-3-fid, concolorous; lamellae free, remote,
subconfertous, ventricose, at first flesh-colored, then
isabel-colored; spores ellipsoid, uniguttate, smooth,
6-Tx4 p.

On wet earth in a basement, University Campus, Lin-
eoln. (12111)

Pluteolus glutinosus Clements.

Pileus membranaceous, conico-campanulate, then ex-
planate and repand, glabrous, umbonate, thickly cov-
ered with a tenacious mucilage, margin striate to the
middle, at length split, gray-stramineous, fuscescent
toward the margin, 13-2 cm. wide; stipe graceful,
hollow, shining, equal, densely fibrillose-pulverulent,
pale ochroleucous, white-striate toward the apex,
3 mm.x 5-10 cm.; lamellae free, distant, ventricose,
brown; spcres ovate or ovate-ellipsoid, smooth, amber,
13-16x10-12 p.

Among stercorate leaves, Otowanie woods. (12112)

Naucoria striata Clements and Shear.

Pileus carnose, convex, at length explanate or repand,
glabrous, glutinous, ochroleucous, paler toward the
margin, gregarious, 3-6 cm.; stipe broad, equal or sub-
incrassate at the base, sometimes compressed, solid
or medullate in age, fibrous, beautifully lineate from
the apex to the middle, silky-fibrillose or squamose,
above shining, pale cremeous, below fuscescent, 138-15

NEW SPECIES OF FUNGI 11

mm.x4-7 cm.; lamellae free, somewhat crowded,
ventricose, at first pale umber, then ferruginous,
spores ovoid, smooth, ferruginous, 7-8x5 #.

On rich ground, Lincoln. (12113)

Cortinarius squarrosus Clements.

Pileus carnose, campanulate, at length convex, dry,
scarcely umbonate, markedly squarrose at the center
with umber, fibrillose-fasciculate scales, densely cov-
ered toward the margin with subsquarrose fibrils, um-
ber or umber-ochroleucous, 24-3 cm.; stipe hollow,
fibrose-carnose, flexuous, subequal, subsquarrose with
fulvous-umber fibrillose scales, 5 mm. x 3-4 cm.; lam-
ellae slightly adnexed, ventricose, somewhat crowded,
fulvous or umber; fibrils of the veil umber, fugacious;
spores irregularly ellipsoid, smooth, eguttate, 12x6 ».

Among grasses in the woods, Little Blue river, Endicott.
A small form of this species has the pileus and stipe
paler and the stipe scarcely squarrose; pileus 12 mm.
wide, stipe 2mm.x16 mm. (12114)

12 BEPORT ON RECENT COLLECTIONS

ADDITIONS TO THE REPORTED FLORA OF THE
STATE

[ * Indicates new host only, ]
CHROOCOCCACEAE

Chroococcus minor (Kuetz.) Naeg.
In aquarium, Lincoln. (12115)
Gomphosphaeria aponina Kuetz.
In aquaria, Lincoln. (12116)

NOSTOCACEAE

Nostoc linkia (Roth) Born.

In ponds, South Bend. (12117)
Nostoc macrosporum Menegh.

On pots in greenhouse, Lincoln. (12118)
Nostoc sphaericum Vaucher.

On soil in greenhouse, Lincoln. (12119)
Nostoc verrucosum Vaucher.

In culture in greenhouse, Lincoln. (12120)
‘Anabaena hallensis (Jancz.) Born. and Flah.

In aquaria, Lincoln. (12121)
Nodularia harveyana Thuret.

In ponds and running water, South Pend. (12122)

OSCILLATORIACEAB

Lyngbya confervoides C. Ag.

In culture from salt basin, Lincoln. (12123)
Lyngbya major Menegh.

In aquaria, Lincoln. (12124)
Lyngbya semiplena J. Ag.

In pond, South Bend. (12125)

ADDITIONS TO REPORTED FLORA

Lyngbya spirulinoides Gomont.

On moist earth, Lincoln. (12126)
Vaginaria chthonoplastes (Hofman-Bang).

On moist saline earth, Lincoln. (12127)
Vaginaria oligothrix (Kuetz.) OK.

On wet soil, Lincoln. (12128)
Vaginaria paludosa (Kuetz.) OK.

On wet soil in greenhouse, Lincoln. (12129)
Oscillatoria amphibia Ag.

In Salt creek; in cultures, Lincoln. (12130)
Oscillatoria chalybea Mertens.

In stagnant water, Waverly. (12131)
Oscillatoria chlorina Kuetzing.

In culture in greenhouse, Lincoln. (12132)
Osctllatoria curviceps Ag.

On moist soil, greenhouse, Lincoln. (12133)
Oscillatoria formosa Bory.

In culture in greenhouse, Lincoln. (12134)
Oscillatoria geminata Menegh.

In aquaria, Lincoln. (12135)
Phormidium ambiguum Gomont.

In aquaria, Lincoln. (12136)
Phormidium corium (Ag.) Gomont.

In ponds, South Bend; Long Pine. (121387)
Phormidium fragile (Menegh.) Gomont.

In aquaria, Lincoln. (12138)
Phormidium laminosum (Ag.) Gomont.

In running water in greenhouse, Lincoln, (12139)
Phormidium subuliforme Gomont.

In aquaria, Lincoln. (12140)
Phormidium tenue (Menegh.) Gomont.

On boards of mill-dam, Milford. (12141)
Phormidium uncinatum (Ag.) Gomont.

In aquaria, Lincoln. (12142)

13

14. REPORT ON RECENT COLLECTIONS

Schizothria tinctoria (Ag.) Gomont.

On Cladophora, Fisher’s Lake, Glen Rock.

Spirulina major Kuetzing.

In Salt creek, Lincoln. (12144)
Spirulina subtilissima Kuetzing.

In Salt creek, Lincoln. (12145)

SCYTONEMATACEAE

Scytonema cincinnatum (Kuetz.) Thur.

In ponds, Nebraska City. (12146)
Scytonema ocellatum Lyng.

On pots in greenhouse, Lincoln. (12147)

BACTERIACEAE

Spirillum sanguineum (Ehrenb.) Cohn.

In a culture of algae, Lincoln. (12148)
Spirochaete plicatilis Ehrenb.

In cultures of algae, Lincoln. (12149)
Bacterium lactis Lister. '

In sour milk, Talmage. (12150)

DESMIDIACEAE

Cosmarium margaritiferum Menegh.
In tank, Salem. (12151)

BACILLARIACEAB

Achnanthes affinis Grun.
Fairbury. (12152)
Achnanthes hungarica Grun.
Fossil, Mulien. (12153)
Amphipleura pellucida (Ehbr.) Kuetz.
Arago, Weeping Water. (12154)
Cymbella bengalensis De Toni.
Wahoo. (12155)

(12143)

ADDITIONS TO REPORTED FLORA 15

Cymbella lanceolata (Ehr.) Kirchn.

Fossil, Mullen. (12156)
Cymbella levis Naeg.

Fossil, Mullen. (12157)
Cymatopleura solea (Breb.) W. Sm.

Rulo, Talmage, Brock, Plattsmouth, Nemaha City,

Weeping Waier, Fairbury, Lincoln. (12158)

Cystopleura oceilata (Ehr.) Kuntze.

Fossil, Mullen. (12159)
Eunotia arcus Ebr.

Fossil, Greeley county, Mullen. (12160°
Eunotia diodon Ehr.

Fossil, Mullen. (12161) é
Fragilaria construens (Ebr.) Grun.

Fossil, Mullen, Thedford, Wheeler county. (12162)
Frustulia vulgaris (Thwaites) De Toni.

Brock, Peru, Julian, Talmage. (12163)
Gomphonema eriense Grun.

Long Pine. (12164)
Gomphonema herculaneum Ebr.

Fossil, Mullen. (12165)
Gomphonema insigne Greg.

Crete. (12166)
Gomphonema vibrio Ehr.

Fossil, Mullen, Greeley county. (12167)
Navicula appendiculata (Ag.) Kuetz.

Brock. (12168)
Navicula bacillum Ebr.

Auburn. (12169)
Navicula braunti Grun.

Talmage. (12170)
Navicula cincta (Ehr.) Kuetz.

Talmage, Nemaha City, Arbor. (12171)
Navicula crucicula (W. Sm.) Donkin.

Arbor. (12172)

16 REPORT ON RECENT COLLECTIONS

Navicula elliptica Kuetz.
Holt county, Johnson, Long Pine; fossil, Mullen.
(12173)
Navicula gigas (Ehr.) Kuetz.
Fossil, Mullen. (12174)
Navicula hungarica Grun.
Fossil, Mullen. (12175)
Navicula legumen Ebr.
Brock, Auburn; fossil, Mullen. (12176) .
Navicula menisculus Schum.
Long Pine. (12177)
Navicula minuscula Grun.
Nebraska City, Peru. (12178)
Navicula mormonorum De Toni.
Auburn. (12179)
Navicula nobilis (Ehr.) Kuetz.
Fossil, Mullen. (12180)
Navicula reinhardtii Grun.
Long Pine, Fairbury. (12181)
Navicula rhynchocephala Kuetz.
Fairbury. (12182)
Nitzschia balatonis Grun.
Lincoln. (12183)
Niteschia dissipata (Kuetz.) Grun.
Long Pine. (12184)
Nitzeschia obtusa W. Sm.
Fossil, Mullen. (12185)
Niteschia sinuata (W. Sm.) Grun.
Fossil, Mullen. (12186)
Niteschia spectabilis (Ehr.) Ralfs.
Holt county; fossil, Mullen. (12187)
Pleurosigma eciotoense Sulliv.
Crete. (12188)
Rhoicosphenia curvata (Kuetz.) Grun.
Brock. (12189)

ADDITIONS TO REPORTED FLORA 17

Rhoiconeis rhomboides Elmore.
Arago, Fairbury, Brock, Long Pine. (12190)
Stauroneis acuta W. Sm.
Brock. (12191)
Stauroncis bicapitata Elmore.
Holt county. (12192)
Synedra bicurvata Biene.
Talmage, Johnson. (12193)
Stauroneis minutissima Lagerst.
Fossil, Mullen. (12194)
Tetracyclus lacustris Ralfs.
Fossil, Greeley county. (12195)

ZYGNEMATACEAE

Spirogyra nitida Dillw.
In Fisher’s Lake, Glen Rock. (12196)

MUCORACEAH

Hydrogera oedipus (Mont.) O. K.
On horse dung, Little Salt creek. (14595)

HYDROGASTRACEAE

Protosiphon botryoides (Kuetz.) Klebs.
On wet earth in greenhouse, and in fields, Lincoln.

(123802)
PERONOSPORACEAE

Peronospora trifoliorwm De Bary.
On Astragalus canadensis, Long Pine. (12027)

ULOTRICHIACEAE

Conferva tenerrima rhypophila (Ikuetz.) Hansg.
In tanks, Peru, Salem, Talmage, Dawson, Brock.
(12197)
Hormiscia rivularis (Kuetz.) De Toni.
In creek, Arbor; Lincoln. (12198)
Hormiscia subtilis variabilis Kuetz.
on tanks, Talmage, Auburn, Salem. (12199)

18 REPORT ON RECENT COLLECTIONS

Microthamnion kuetzingianum Naeg.
In trough, Peru. (12200)
Stigeoclonium longipilum minus Hansg.
In trough, Brock. (12201)

CHROOLEPIDACEAE

Trentepohlia umbrina Kuetz.
On bark of Ulmus americana, Georgetown. (12202)

SPHAERIOIDACEAE

Phoma nebulosa (Pers.) Mont.

On Urtica gracilis, Valentine. (12038)
Phyllosticta api Halsted.

On Apium petroselinum, Kearney. (12204)
Phyllosticta iridis E. & E.

On Rhus toxicodendron, Long Pine. (4658)
Cytospora negundinis E. & E.

On Acer negundo, Atkinson. (12087)
Septoria aurea E. & E.

On Ribes aureum. (12€5)
Septoria avenae Frank.

On Avena striata, Long Pine. (12205)
Septoria caricis Pass.

On Carex pennsylvanica, Merriman. (12050).
Septoria lycopersicit Speg.

On Solanum lycopersicum, Pawnee. (12839)
Septoria menispermi E. & H.

On Menispermum canadense, wing. (4661)
Septoria pachyspora E. & H.

On Xanthoxylum americanum, Kennedy. (12086)
Septoria pctroselini apii B. & C.

On Apium petrosclinum, Kearney. (4724)
Septoria steironematis TE. & E.

On Stcironema ciliatum, Kennedy. (4672)
Camarosporium compositarum (C. & Harkn.)

On Artemisia frigida, Atkinson. (12049)

ADDITIONS TO REPORTED FLORA 19)

LEPTOSTROMATACEAE

* Discosia artocreas (Tode) Fr.
On leaflets of Gleditsia triacanthos, Brownville. (4590)

EXCIPULACEAE

Dinemasporium decipiens De Not. & Sace.
On decorticated twigs of Acer negundo, Lincoln.
(4793)
* Dinemasporium graminum Lev.
On Sporobolus vaginiflorus, Lincoln. (12206)

MELANCONIACEAB

Cylindrosporium tradescantiae Ell. & Kell.

On Tradescantia virginica, Inman. (12207)
Cylindrosporium padi Karst.

On Prunus denvissa, Valentine. (4654)

Didymosporium corticola Schw.
On Rhus toxicodendron, Long Pine. (4658)

MUCEDINACEAR

Sterigmatocystis candida Sacc.

In human ear, Lincoln. (12208)
Streptothrix abictina Peck.

On decorticated wood, Lincoln. (12210)

SPORODESMIACEAB

Alternaria tenuis Nees.
On Calamagrostis confinis, Poa pratensis, Long Pine.
(947, 12218)
Cercospora cleomes Ell. & Halst.
On Cleome serrulata, Ewing. (4660)
Cercospora desmodu Ell. & Kell.
On Meibomia paniculata, Long Pine. (12083)
Cercospora effusa Ell. & Ev.
On Lobelia syphilitica, Long Pine. (12025)

20 REPORT ON RECENT COLLECTIONS

Cercospora tuberosa Ell. & Kell.
On Apios apios, Long Pine. (12024)
Fusicladium depressum B. & Br.
On Sium cicutifolium, Kennedy. (12211)
Heterosporium gracile (Wallr.) Sace.
On Iris pumila, Long Pine. (936)
Coniosporium miserrimum Karst.
Leng Pine. (12209)
Stigmina clavulata (C. & Harkn.) Pound & Clements,
Valentine. (12212)

STILBACEAE

Coremium bicolor (Web.) Pound & Clements.
On dung in culture, Lincoln. (4593)

ERYSIBACEAE

* Sphaerotheca humuli (DC.) Burrill.

On Rosa arkansana, Rosa sp. (cult.), Geum canadense.
Lincoln. (12218, 122193)

On Iris versicolor, Otoe county. (12077)

Sphaerotheca humuli fuliginea (Schlecht.) Salmon.

On Leptilon canadense, Lincoln (12221); Verbena
urticifolia, Otoe county. (12076)

* Podosphaera oxyconthae (DC.) De Bary.

On Prunus besseyi, Long Pine. (4630)

* Microsphacra alni (DC.) Wint.
Juglans nigra, Lincoln. (12215)
* Hrysibe cichoracearwm DC.

On Scutellaria laterifiora, Atkinson (12031); Aster
paniculatus (1047), Helianthus rigidus (12227),
Helianthus grosse-serratus (12230), Lappula virgin-
ica (12228), Parictaria pennsylvanica (12229),
Plantago rugellii (1225), Lincoln.

* Erysibe graminis DC.
On Poa pratensis, Lincoln. (1221)

ADDITIONS TO REPORTED FLORA 21

* Erysibe polygoni DC.

On Polygonum aviculare (12238) and P. erectum
(12241), Faleata pitcheri (12242), Pisum sativum
(12240), Rumex salicifolius (12237), Lotus ameri-
canus (12239), Lincoln; Solanum carolinense, Cass
county (12078).

SPHAERIACEAE

Calosphaeria barbirostris (Dufour) Ell. & Ev.

On dead wood of Quercus, Weeping Water. (4701)
Eutypella stellulata (Fr.) Sace.

On dead twigs of Ulmus, Lincoln. (4709)
Leptosphaeria culmicola (Fr.) Karst.

On Elymus canadensis, Kennedy. (12089)
Leptosphaeria doliolum (Pers.) Ell. & Ev.

On Helianthus maximiliani. (12088)
Pleospora andropogonis Niessl.

On Muhlenbergia racemosa, Kennedy. (12217)
Pleospora permunda Cooke. ,

On Asclepias syriaca, Johnstown. (12090)

HYPOCREACEAE

Nectria epichloe Speg.

On Chrysopogon avenaceus, Long Pine. (12084).
Claviceps nigricans Tul.

On Eleocharis glaucescens, Lincoln. (1264)

DOTHIDIACEAE

* Phyllachora graminis (Pers.) Fckl.

On Sporobolus cuspidatus, Long Pine. (12220)
Dothidea muhlenbergiae Ell.

On Muhlenbergia racemosa, Ewing. (12047)

MOLLISIACEAE

Mollisia sublividula (Nyl.) Karst.
On old wood, Barney creek, Keya Paha county. (12222)

22 REPORT ON RECENT COLLECTIONS

Lachnum agaricinum Retz.
On wet wood, Dry Branch. (12285)

ASCOBOLACEAE

Ascobolus stercorarius (Bull.) Rehm.
On horse dung in greenhouse, Lincoln. (12223)
Ascobolus atrofuscus Phill. & Plow.
On wet sand~ ground in the North Platte river, Gering.
(12224)
Ascophanus carneus difformis Karst.
On manure in greenhouse, Lincoln. (12226)

PEZIZACEAD

Plicaria sepiatra (Cooke) Rehm.
On wet, decaying wood and on ground among mosses,
Niobrara river, Keya Paha county. (12231)
Barlaca constellatio humosa (Fuckel) Clements.
Crouania humosa Fuckel.
On ground, Mead’s Spring, Brown county. (12243)
Humaria salmonicolor B. & Br.
On wet earth, Lincoln. (4706)
Neottiella ollarigs (Fr.) Clements.
Humaria ollaris Fr.
‘On leafy ground, Otowanie woods. (12244)
Scutellinia stercorea (Pers.) Cooke.
On horse dung, Lincoln. (4597)
Scutellinia pu'cherrima (Cr.) Cooke.
On muddy creek banks, Otowanie woods, Lincoln.
(12284)

UDREDINACEABR

* Uromyces appendiculatus (Pers.) Lk.
On Phaselous vulgaris, Experiment Station (12245), on
Aptos apios, Kirkland (12062)

ADDITIONS TO REPORTED FLORA 23

Uromyces peckianus Far.
On subterranean stems of Distichlis maritima, Alliance.
(12043)
Uromyces rosicola E. & E.
On Rosa sp. Crawford. (12266)
* Uromyces trifolii (A. & S. ) Wint.
On Trifolium repens, Experiment Station. (12246)
Puccinia asparagi D.C.
On Asparagus officinalis, Peru (12251), Lincoln
(12029), Purdum (12248), Atkinson (12019)
* Puccinia asteris Duby.
On Aster multifiorus, Merriman (12249), on A. panicu-
latus, Experiment Station (12247)
Puccinia batesiana Arthur.
On Heliopsis scabra, Long Pine. (12023)
* Puccinia caricis (Schum.) Reb.
On Carex stricta, Long Pine (12250), on Carex lazi-
flora blanda, Long Pine (12253)
Puccinia eleocharidis Arthur.
On Eleocharis glaucescens, Long Pine. (12254)
* Puccinia emaculata Schw.
On Eragrostis pectinacea, Experiment Station. (12260)
Puccinia gentianae Lk.
On Gentiana puberula, Lincoln. (12261)
Puccinia heterospora B. & C.
On Abutilon abutilon, Peru (12259), Nebraska City
(12264)
Puccinia kuhniae Schw.
On Kuhnia eupatorioides, Lincoln. (12252)
* Puccinia nigrescens Pk.
On Salvia pitcheri, Lincoln. (12258)
* Puccinia obtecta Pk.
On Scirpus pungens, Chadron. (12255)
* Puccinia polygoni Pers.
On Polygonum convolvulus, Peru (12256), Experiment
Station (12257)

24 REPORT ON RECENT COLLECTIONS

* Puccinia pruni Pers.
On Prunus besscyi, Experiment Station (12262), on P.
serotina, Experiment Station (12263)
* Puccinia solidaginis Pk.
On Solidago nemoralis, Wood Lake. (12265)
Melampsoreila cerastii (Pers.) Schultz.
On Cerastium vulgatum, Long Pine. (12267)
Peridermium cerebrum Pk.
On Pinus scopulorum, Long Pine. (12268)
Uredo gaurina (Pk.) Sace.
On Gaura biennis, Lincoln (12270), on G. parviflora,
Lincoln (12271)
* ‘Aecidium compositarum Mart.
On Aster paniculatus, Peru (12272), A. levis, Peru
(12273), A. multifiorus, Peru (12274), Solidago rig-
ida, Lincoln (12275), S. serotina, Lincoln (12276),
S. missouriensis, Belmont (12277), Hrigeron phila-
delphicus, Peru (12278)
Aecidium compositarum santhii Burrill.
On Xanthium canadense, Peru. (12279)
Aecidium dracontii Selm.
On Arisaema dracontium, Peru. (12280).
‘Aecidium gaurae E. & E.
On Geura parviflora, Peru. (12281)
* Aecidium polemonii Pk.
On Phlox divaricata, Cedar creek. (12282)
* Aecidium punctatum Pers.
On Anemone caroliniana, Lincoln. (12283)

USTILAGINACEAE

Burrillia pustulata Setch.
On Sagittaria latifolia. (12269)

LABOULBENIACEAE

Laboulbenia brachini Thaxter.
On Brachinus kansanus, South Bend. (4720),

ADDITIONS TO REPORTED FLOEA 2h

Laboulbenia elongata Thaxter.
On Platynus sp. (4722)
Laboulbenia galeritae Thaxter.
On Galerita janus (4719) and G. nigropes. (4718)
Leaboulbenia variabilis Thaxter.
On Chlaenius pennsylvanicus (4715), prasinus (4716),
sericeus (4717), and solitarius (4714)

CLAVARIACEAR

Clavaria subtilis Pers.
On acorn cups, Naponee. (4708)

POLYPORACEAB

Trametes sepium Berk.
On decaying oak, Lincoln. (4710)

AGARICACEAE

Tricholoma melaleucum Fr.

On ground in woods, Lincoln. (12286)
Tricholoma personatum Fr.

On ground in Otowanie woods. (12287)
Pleurotus petaloides Bull.

Lincoln. (12288)
Volvaria parvula Weinm.

On wet ground, Lincoln. (12289)
Annularia levis Krombh.

On ground among grasses, Lincoln. (12290)
Agaricus silvaticus Schaeff.

On ground in Otowanie woods. (12291)
Hypholoma candolleanum Fr.

On wet earth, Lincoln; on ground in Otowanie woods.

(12292)

Panaeolus phalaenarum Fr.

On horse dung, Lincoln. (12293)
Panaeolus solidipes Peck.

On dung, Otowanie woods. (12294)

26 REPORT ON RECENT COLLECTIGNS
NIDULARIACEAB

Cyathus rufipes BE. & B.
On dung, Kennedy. (12295)

RICCIACEAB

Riccia crystallina L.

On ground, Wymore. (12296)
Sphaerocarpus terrestris Smith.

On ground, Wymore. (12297)

JUNGERMANNIACEAR .

Aneura pinguis (L.) Dum.
On ground, Peru. (12298)

BRYACEAR

Barbula subulata Beauv.
Long Pine. (6697)
Encalyptra ciliata Hedw.
Long Pine. (6684)
Leskea obscura Hedw.
Franklin county. (6687)
Polytrichum commune L.
Franklin county. (6683)
Webera cruda Schimp.
Long Pine. (6688)

LILIACEAB

Lilium umbellatum Pursh.
Watt’s Lake, Cherry county. (12015))

GRAMINACEAB

Bromus hordeaceus L.
Long Pine. (12057)

Bromus tectorum L.
Minden. (12299)

ADDITIONS TO REPORTED FLORA

CYPERACEAB

Cares fusca All.

Kirkwood, Rock county. (12055).
Scirpus campestris Britton.

Long Pine.

CRUCIFERACEAD

Sisymbrium altissimum L.
Ewing. (12012)
VIOLACEAR

Viola tenella Muhl.
Stella. (12300)

ERICACEAB
Pirola elliptica Nutt.
Long Pine. (12001)

CAPRIFOLIACEAB

Viburnum prunifolium L.
Johnson. (12301)

THE PRAIRIE-GRASS FORMATION IN REGION I
By Joun J. THORNBER

INTRODUCTION

During the last three years the writer has carried on several
lines of phytoseographical investigation about Nebraska
City, Neb., with a view of bringing results together ultimately
and presenting them to the Faculty of the University of Ne-
braska as a thesis for the degree of master of arts. On
account of school duties, the work has not been pursued as
vigorously at all times, particularly during late spring and
autumn, as was desirable. When circumstances were favor-
able, however, all possible naste, consistent with a proper
degree of accuracy, was made.

The pieces of apparatus needed were designed largely as
necessity dictated, and, as is generally the case under similar
circumstances, a desirable degree of accuracy was not always
obtained by their use. It is gratifying to know that now we
may expect greater precision in determining physical factors,
from the excellent and inexpensive apparatus designed by
Dr. Clements and Mr. Hedgecock of the University.

To Dr. Clements in particular the writer is deeply indebted
for the invaluable assistance rendered from time to time,
for the many personal conferences, and for the timely sug-
gestions ever freely given. More than this, Dr. Clements has
furnished niany invaluable outlines for extended research,
and under his supervision alone what is now presented was
made possible. The “Phytogeography of Nebraska,” by Drs.
Pound and Clements, was also a valuable incentive to the
work. To Mr. E.R. Yundt, of the Nebraska City high school,
the writer is indebted for the accurate topographical survey

30 STUDIES IN THE VEGETATION OF THE STATE

of the prairie on which the formational work was conducted.
Mr. Frank Zimmerer has rendered invaluable assistance in
photography and map-finishing in water colors, and also
along other lines.

Throughout this treatise, the metric system of measures,
the Fahrenheit thermometer scale, and the nomenclature
based upon Britton and Brown’s “Illustrated Flora” are
used. The author-citation is not considered imperative here,
and accordingly is omitted.

Before any work of importance can be accomplished in
phytogeography, the physiography of the region as well as the
flora must be adequately in hand. This is especially empha-
sized in the study of the formation, where it will be discussed
to some extent. The work of becoming acquainted with the
flora and the physiography of the country about Nebraska
City was begun in the autumn of 1897 and continued through-
out the following year. During this time, also, a complete col-
lection of the plants was made and deposited with the botan-
ical department of the University of Nebraska. The pheno-
logical notes taken during this year were not considered
extensive enough to be of importance; this leaves the pheno-
logical records for 1899 and 1900, which were made as ac-
curate and complete as conditions would permit.

The more important lines of investigation, with brief ex-
planatory notes, are here given:

I. Physical factors.
1. Physical data consisting of,

a. Soil temperature at a depth of ten centimeters.

b. Psychrometer readings (wet and dry bulb ther-
mometers) at surface of ground and one meter
above.

c. Meteorological conditions as to amount and di-
rection of wind, amount and seasonal distri-
bution of precipitation and sky conditions,
whether clear, overcast, or cloudy.

d. Determination of physical ~water-content.

INTRODUCTION 31

e. Determination of light-intensity.
II. Vegetation-forms of the flora, including accessory bio-
logical characters.
1. Classification of the flora according to vegetation-
forms.
2. The study of rosettes and rosette-forming plants.
3. The study of buds with especial reference to protec-
tion.
4, Observations concerning seed-production and dissemi-
nation.
. The study of the pollination of plants,
. The preparation of a complete phenological record
for each species to include the following:
Earliest appearance of leaves.
. Earliest appearance of flowers.
Maximum flowering period.
. Length of flowering period.
Earliest maturation.
Period of maturation.
. Dying of parts of herbs, and leaf-fall of trees.
%. Observations upon various other phenomena, as foli-
age movements, etc., falling under accessory biolog-
ical characters.
III. Ecological relations.
1. The classification of the flora into habitat-groups.
IV. The study of the formation, summing up all the previous
lines of investigation.

o> Or

Qmse Asa os

32 STUDIES IN THE VEGETATION OF THE STATE

DISCUSSION OF ECOLOGICAL FACTORS

With the exception of light and physical water-content
factors, observations were taken daily, except Sunday,
throughout the period of active vegetative growth, from
March 20 to December 7, 1900, in the four locations, prairie
or I, thicket or II, open woodlands or III, and deep wood-
lands or IV. Observations were taken between 5:00 and
6:00 p.m. from March 20 to May 5, beginning with location I
and ending with IV; between 6:00 and 7:00 p.m. from May 5
to September 7; between 5:00 and 6:00 p.m. from September
8 to October 26. After the latter date conditions were noted
daily from 4:00 to 5:00 p.m. During a considerable portion
of the time the psychrometer readings were taken at the
surface and one meter above the surface of the ground. Be-
ginning with July 1 the psychrometer data in the first col-
umn represent conditions at the earth’s surface, and those
in the second column conditions at the height of one meter.
In all cases soil temperatures were taken ten centimeters
below the surface.

The direction of the wind, indicated in the factor record
by the letters N., 8., E., W., N. E., N. W., 8. E., S. W., ete,
and amount of wind are at best approximations, as no ane
mometer was used. The sky condition for. each day is in-
dicated by the characters SS 1, signifying few or no clouds;
SS 4, half overcast; Cl 2, mostly overcast; and Cl 1, entirely
overcast.

Relative precipitation factors were obtained by measuring
the rainfall in a vessel partially sunk in the ground, the
amount being indicated in each case in centimeters. The
physical water-content was determined from samples of soil,
taken to a depth of six to ten cm., collected semi-weekly and
placed in air-tight tin boxes of known weight. These were

DISCUSSION OF ECOLOGICAL FACTORS 33

carefully weighed, the contents dried in an oven, and again
weighed. The loss in weight represents the physical water-
content.

To obtain light factors in the four locations, strips of
“Solio” paper were ruled lightly with a violet lead and ex-
posed to the sun’s rays until the lines entirely disappeared,
the time required in each instance being noted. Observations
were made on clear days between 12:00 and 2:30 p.m. In
determining light factors, there are many difficulties to be
overcome before even fairly accurate results may be expected.
The angle of inclination of the sensitized paper to the sun’s
rays is not always the same, the sky is not uniformly clear
even though cloudless, and, disregarding deflection, reflec-
tion, and absorption, the amount of light received on a given
surface varies as the sine of the angle of elevafion. Accord-
ingly, paper exposed in woodland or thicket for a given
period will receive much more than one-half of the total
amount of light during the first half of the exposure. As
stated heretofore, these difficulties are already being antici-
pated.

A careful examination of the ecological factors found in
another part will reveal many interesting relations, the more
important of which are here noted. Atmospheric and soil
temperatures, humidity, physical water-content, light ratios,
and, in fact, most other ecological factors are minimum in
the four locations during the spring and autumn months
and become maximum only during the summer months. The
air temperature of the prairie formation is from .5°-10°
higher than corresponding temperatures in deep woodlands,
from .2°-3.5° higher than temperatures in open woodlands,
and from .5°-10° higher than corresponding temperatures
in dense thickets. If for the time we consider prairie con-
ditions normal, we shall conclude that these differences are
due to the controlling woody plants in locations II, III, and
IV, since where the trees are less controlling, as in III,
temperature differences are accordingly reduced. Tem-

3

34 STUDIES IN THE VEGETATION OF THE STATE

perature differences between the prairie formation on the
one hand and thicket and deep woodland formations on the
other range from .2°-5° during the early spring months,
and from 2°-12° 15° during the summer months.

Soil temperatures are invariably higher in I than in II,
If], or IV. During the spring and autumn these differ-
ences range from 2°-5°, while in midsummer it is not un-
common for the soil temperature of the prairie to range
12°-20° higher than corresponding temperatures in thickets
and woodlands. Soil temperatures of location I show great-
est variations, 10°-20° in twenty-four hours being not infre-
quent. Similar temperatures in woodlands and thickets are
relatively stable, the changes being gradual and of a less
degree. It is also to be noted that soil temperatures taken
at a number of stations in the same formation show little
variation if conditions are similar. Immediately after a
heavy precipitation, temperatures of the soil in all forma-
tions are observed to have approached almcst a common
degree.

Psychrometer data indicate the least amount of atmos-
pheric humidity in the prairie formation and the greatest
amount in thickets and deep woodlands; in this relation,
as would be expected, open woodlands are intermediate. As
a rule, the wet-bulb thermometer registered .2°-3° lower
at a height of one meter than at the earth’s surface, thus
indicating a greater evaporation of the water particles from
the bulb and hence less humidity in the atmosphere at this
height. The dry-bulb thermometer recorded in most cases a
temperature of .2°-2.5° higher one meter above than at the
earth’s surface. These conditions are found to be true, in
general, for the various formations, and they explain to a
considerable extent the habits of certain plants of our flora,
which tend to develop mesophytic leaves near the ground
and xerophytic leaves above. It goes without saying that,
when the atmosphere is laden with moisture, little or no
difference is observed between the wet- and dry-bulb ther-

DISCUSSION OF ECOLOGICAL FACTORS 35:

mometers, and that conditions of humidity at the earth’s
surface are essentially those one meter above.

The physical water-content of the soil is least in location
I, greatest in II and IV, and intermediate in III. These
conditions in a general way hold good throughout the active
growing period. Immediately after a heavy precipitation,
the water-content of the soil, theoretically at least, is the
same for all locations, but the direct exposure of the sun’s
rays, combined with the greater atmospheric movements in
I, produce a much more rapid evaporation than is possible in
wooded formations. Accordingly, variations of the physical
water-content of the prairie formation are more abrupt than
in any other, assuming of course that the soil composition is
the same throughout. During certain portions of May and
June, 1900, the physical water-content of location I ranged
from 3-9 per cent; at other times in June, July, and
August, this soil contained 25 per cent and even 35 per cent
of water for a short time. Locations II and IV maintained
18-26 per cent of water in the soil for the greater portion
of the year. Immediately after precipitation, 30-38 per cent
of soil water is not uncommon in woodlands; this is reduced
to 9-14 per cent during the drier parts of the year.

Since the amount of light on a given surface varies as the
sine of the angle of elevation, light conditions in the prairie
formation are minimum in early spring and autumn, and
maximum during midsummer. For each day, there is also
a maximum of light (12:00 M.) and two minima (morning
and evening). As a result of the foliage, the light relations
in locations II, III, and IV are just the reverse of those in
location I, viz., maximum light obtaining in the spring and
autumn, and minimum light during midsummer. From the
above, it follows that the amounts of light in the four loca-
tions are nearest equal in early spring, before the foliation
of the woody plants, and in autumn after the leaves have
fallen. This can readily be seen by a comparison of light
ratios given below, which are taken from the ecological fac-

36 STUDIES IN THE VEGETATION OF THE STATE

tors. The relative amount of light in each of the above loca-
tions on March 31 may be expressed by the following ratios:
(Light amount) I : (Light amount) II :: 1 : 1.583
(Light amount) I : (Light amount) III :: 1 : 1.250
(Light amount) I : (Light amount) IV :: 1 : 1.500
On June 6 the light relations between the four locations
were as indicated:
(Light amount) 1 : (Light amount) II :: 1: 220
(Light amount) I : (Light amount) III :: 1: 5
(Light amount) I : (Light amount) IV ::1: 32
The following light ratios obtained September 8 and Novem-
ber 3, respectively :
(Light amount)

(Light amount)
(Light amount)

: (Light amount) II :: 1 100
: (Light amount) III :: 1: 4
: (Light amount) IV :: 1: 12
a ad
sock

(Light amount) : (Light amount) II 2

(Light amount) : (Light amount) III >: 13

(Light amount) I : (Light amount) IV ::1: 2.6

In every location results clearly indicate more light at
the height of one meter than at the earth’s surface. It is
more than likely that considerable error will be found in
thicket and deep woodland factors owing to the length of
time required to sufficiently blacken the paper, but, after
allowing for all possible error, the facts remain materially
unchanged.

The thicket formation from which the light factors were
obtained is a veritable jungle of Xanthorylum, Corylus,
Cornus, and Prunus, sparingly interspersed with Ulmus,
Robinia, Gleditsia, and Crataegus. Rhus glabra and Ribes
gracile with Menispermum as a climber are common along
its borders, and in many places it is overgrown with Vitis,
Parthenocissus, and Smilax. It is worth while to note the
species of herbaceous plants growing in this thicket, also
their flowering period. Viola obliqua, V. scabriuscula, Ery-
thronium albidum, Bicuculla cucullaria, Carex grisea, C.

i |

DISCUSSION OF ECOLOGICAL FACTORS 37

laxiflora, Phlox divaricata, Hydrophyllum virginicum, Wash-
ingtonia longistylis, Ranunculus abortivus, and a few other
species of lesser importance make up the entire list of herba-
ceous bloomers, and these, with the exception of Geum cana-
dense, have completed anthesis before June 1. Plants grow-
ing in dense woodlands are compelled, as is evidenced by the
specialization and adaptation of parts, to blossom before the
dense foliage of the upper woody layers appears, in order to
secure a good exposure to light and heat. Upon examining
these plants, we find seven, Viola obliqua, V. scabriuscula,
Carex grisea, C. laxiflora, Phlox divaricata, Ranunculus
abortivus, and Geum canadense, are rosette formers, two,
Erythronium and Bicuculla, produce bulbs, and one, Wash-
éngtonia, develops thickened fleshy roots. These adaptations
enable plants to gain an early start in the spring when maxi-
mum light obtains in woodlands. Similar conditions are
found in location IV, but not to the same extent, since here
the struggle for light is not so desperate, and a larger number
of species are enabled to secure favorable conditions,

38 STUDIES IN THE VEGETATION OF THE STATE

ECOLOGICAL FACTORS
TEMPERATURE AND ATMOSPHERE

{Owing to the length of the complete record, it is given only for a few days im each month.}
I—Prarrig. II1—Deep Taroxet. [I—Oren Woopuanp. IV—Derp t'orsst.

DATE HOUR a Z AIR TEMP. WET BULB. REL. HUM. SorL MBLETEOROL.
“] PM 8 surF.| 1m. | surr.| 1. |sury.| 1a. | T2™?-| sxy. | winp. woes
Mar. 20/5-G:00| ¢ [93° |..... 32° |SS1..|N. Wl]......
“ 2) «lay 821° es 32° “ CS sass a
ae 46 fo} oe “oe
«Sof lay Bte [oor ae foe [owe [ott
«ool oe Py igge fi! 33° «TS Well.
an] lyr 52.991. 127! 33° “ Poet (aaa
“9y) + frarple foo... 33° “ HE Nweoes
at 21 “ce IV 59° siyhbevalia 83° “oe Cam ree
46 Z ae I es wares 88° at eS seme bok
“ce “se fo} ° ae “s
te 99) ae Tir les hie 36° es a) een
« 99) « lryig5.5el.. -! 35° “ “
et Sap ee TT IBOF es age {Cl1..|......
“ 23 “ at 50° ee 34° an ane
“ « |rtri50e | o... 40° anh Meee
“ 93l o+ Iry 49.59/00... 40° an ee
ee ee ne sep oe
“4) oe Tariaze foo! 36° “ «
o 9A “ec TO 41° si ad 38° ity “cc it
i) a oa 36° “ “ “
Apr. 2} « | T 60.59]... 59° 1SS1..1S.w
Qt Lar |59.96] 2277 Be vas
“ “ 59.69). .... ° “ “
alow drvie (20 Bee cae | at Eee
ae oa a a ee 53° 188%.) NEL Joos...
. E “ pes 58.1° ee 46° oak bala ee
“oe °o “ “
«toe leviege (002 nee ee oe
«aloe Trig [007 55° 1SS1..] SB. 1222!
«aloe Ta i55° foe! 46° “ an ee
Ti 0081 51.79)“ roe een
ir cn aay oe 48° “« Cian eee
“ 5] oo TT |eg.2e}. oo! 60° “ ef
“ 6 Tiriese fo... 52° “ ca poe
« 5] o trrrles. ze}. 2! 55° “ a ra
“ 6 “« lrwleae foo... 54° “ Te rl
se oicamie Vie Sar f(a eie “Wsgat ft
“6! lile7.se.. 22! gh ee aces | ees
“ 6 . TIT 68° athe i ae, ae Ra SOIR
Oo rr
«oo TT lez.pel a | Sensmrl enema
“c q “ Ir 67.5°|..... 56° ae od Ooo
“e q “oe TIT 66.1° ae 61° Peer eee a ea
aie U “oe TV 64 ge ee 54° PP Gabe ee eka
* i : PP Tecaulenatin
7) tar bee |. eas] [Nooo
“af oe lTisge fo 2 7? 64° ee
“ 2 Tv 65° |... 62° “ cme ec

DISCUSSION OF ECOLOGICAL FACTORS

ECOLOGICAL FACTORS—Continued

TEMPERATURE AND ATMOSPHERE

I—Pramin. [l—Dgur Turcxer. I1—Orzn Woopianp. IV—Drxp Forrsr

39

DATE HOUR “ Pa AIR TEMP. WET BULB. | REL. HUM soIL MBTEOROL.

Of Pp .
Ms 8 surr| 1m. | svar) 1x. |svar| in. |7™P-| oxy. |win.|

May 3/5-G:00] 7 SS %.IN. W.|......
“a 3 “ Il “a CC area aatt
2 eee eo Pre
Ae EE SS 1..| N.E. ]......
“oa oe fay ale ae eee
oe 4 oe TIL ac OO Peete
“Al TV S £6 Jeseeee
“ 516-6:30] I Ss3.| E. [12cm
oo 6 oe Il “ss “ce “a
wo&® “NT “ “a “
ry 5 “a Iv “ “ “ce
“a 7 “ I 7 sc “ 4% com.
“a 7 “ce Il ae oe ce
“oe 7 “o TI oe “ as
aod «Ty iy “c “ “a

June 1/6-6:40| I SS1..J Nv ]......
“oe 1 “a I ae So Veet ees
“ 1 “6 TIT ee Pepa
eo «© iv 2 ee teresa
Qh 88 I oA ane oer
“ 2 oe II 5 es SST paverevats
“ 2 a6 I i CL oer
«glow ly “ ian etal
«ogo TT ane eee Pee
re gee TT “f gan orion
«gt fe TTT ae eee Coie
«glo ity se $8 A caueca oe
ieee 1 a i 1 B.E. fo...
we 2B oS aI oe ae Peer
“By ft (TTT yi See) oihigietelarers
meee +) aaa |" He aveora sta
«“ 6“ TI HO late ass 16cm
cn] ce 8 8 He liacotes i.
« 6 [TT Bl thane "
ee *) nee | A's Oe Miseceresen can
oo o« Ty SS 4/5.) N.W.) .5 em.
“ 7 “ It oe oo “

ar 7 ‘(TIT “ec “ “
yf “« Ty “ “ oe

Juty 2I6-7:00! I 88 | 3. |83cm.
ae 2 oe TW ‘ “ce ae
“ag « lO “ “ “
“w 9 « IV “ “ “
oe gfo« [I SS Leslee ies yl severees
ee | oa 8 | WE Crees pocac
“3700 (OT SS Lacests eenadte
“BR « TV BO Norte aces be acsanece

40 STUDIES IN THE VEGETATION OF THE STATE
ECOLOGICAL FACTORS—Continued
TEMPERATURE AND ATMOSPHERE
I—Prarmm. [l—Deer Tucker. I1I—Orzn Woopitanp. IV—Dezxp Forxst
nour |4y| AM TEMP: | WET BULB. | REL. HUM. | 201 METEOROL. ase
PATE: EM 8 2 sunF.| 1m. | sonr.| 1. |scre.| 1m. | TEM?) ary. | winp. 7
July 5\G-7:00] J |88.1° 38° 171° «169° 43 | 38 | 90° |SS iy. S. |......
BT aT 180° (80.5°170.5°170° 62 | 60 | 76° BG ee oe ioe
« B) «* WyTT}87° «188° 169° 168° 40 | 35 | 86° BS Se Tee rans
« 5 [py {85.9°186° 170° |69.8°| 45 | 45 | 78° se ame Eee
a «| I |91.7°191.7°|76° |75° 48 | 45 | 94° |SS1. ae
« 6) “ lyr {89° {89° {76° |76° 55 | 55 | 79.8° af ss
« 6 “ iprT}90° 191° {75° |74.3°} 50 | 45 | 90° ee s
« 6 “ ITV {90° 191° {75° |75° 50 | 47 | 82.5° = ee eee
so J] «eT TT 182° 182° =«163.9°/64° 36 | 36 | 90° *f ING. davsces
«UT TIT |78.2°179° = 65.9°164° 53 | 43 | 76° et aan Cerrar e
« T) TTTT|79.9°/80° 63° }62° 38 | 35 | 89° re HO) Ragharesens
“FT ITV 78.8°179° |64.2°/63° 43 | 40 | 79° ss (O leawe ee
Aug. 1/6-7:30) I |85° |85.5°/73° (/71.9°| 56 | 62 | 90° - a ee
meee ( “© TTT 182° = |81,7°|72.8°|72.3°| 65 | 64 | 75° re OF Nas avectis
«DFT “(err ]83° (83.9°/73° /71.8°) 62 | 55 | 80.19)“ page osc
eee | ‘« ITV {82° {82° |73° |72° 65 | 62 | 77° “ ame Pere
«216-7 :00] I |88° (88.1°/71° |(68.1°] 43 | 35 | 90° sf ae ee
ce 2 | TT 182.6°183° = /72.2°171° 62 | 55 | 77° Se Nay Syara aes
se 2) * TTT 85° = |85.5°/70.1°/69° 47 | 43 | 83° ef oun Coe
« 21 «ITv 83° (182.8°/70° (70° | 52 | 52 | 78° ae eee ere
en Bl ee I |88° /87.8°|72° |71.9°] 46 | 46 | 91° if S.E. |......
« 3} 0 J IT $80.2°183.7°/70.2°|71.9°| 61 | 56 | 76° ae HE er aenchs
3] 0“ [TTT 85° = (85.6°/73° |71.3°] 56 | 51 | 84° ee ame rire
3} |TV {84° [85° |72°—«/70.8°| 56 | 50 | 79° . i
«4 | I 187°) 187°) 175.5°|74° 59 | 54 | 89° “e ie
4) © | TT (83.4°184° 174.3°/74° 66 | 63 | 76° “ ee
«Al ITTT184.6°185.2°/74.2°/73.9°] 63 | 60 | 83.49) « ee Rees
“4 ITV 184.19184° 174° (173° 63 | 59 | 79° e he eareere’
«6 « | T (87° = 187.3°173° 172.19 51 | 48 | 90° es aan ener ie
“6 | TT /83.4°]84° /73..79}73° 62 | 59 | TT° sf ae
6) {TIT |85.9°/85.5°173.2°172° 55 | 52 | 86° sf ane era
« 6)“ ITV 184.2°/85° 172° (172° 56 | 53 | 79° ae tm ile chars
«7 | Ty 88° «[e6e ((72.49/72.1°) 46 | 51 | 90° “ ON" Wererersegs
«FU « 1IT 188° (82° =|73.2°172.1°) 62 | 62 | 77° i oe UW aceas
« T| « JTIT}85° 185° «(73° «172° | 56 | 53 |} 81° a SOD eraussavers
« GT ** ITV 185.4°185.4°173° 172.1°| 56 | 53 | 82° ut ane ee
Sept.11/5-6:00! I {71° |71.2°164.19/64.1°] 68 | 68 | 78° ISS 4.) N. 3.5cem
“« Ul) |IT}70° =|70° = 166.4°}65° 81 | 77 | 73° we bh ae
“4 ‘© 1TIT}70.4°|70.4°165° 165° 15 | 75 | 73° - ef ai
er 1d, “ITV 170° |70° |66° |65° 81 | 77 | 76° ee sa
** 1215-6:30) I |71° |71.7°|63.9°/62.5°] 68 | 61 | 77° |SS1 8.
*e 12)" IT 67° 166.5°164° [63° 85 | 82 | 71° of ss
12) «= |TTTJ68° «68° 64° 63° 81 | 76 | 76° as ts
« 12) «|TV 167.5°|67.5°|64° 163.89] 83 | 80 | 70.59 «* es
‘* 1315-6:00! I 184° 184.5°/72.4°|72.2°] 57 | 56 | 83° Ge Be rote
13; «* =| IE ]80° 181° |70.99/70.4°| 64 | 60 | 72.5° " Be Ne igcaices
“| 13)“ 1HIT181.5°182° |71.5°|71° 61 | 58 | 80° ae ME | cares
« 13/ « [Tv |so° |80.8°170.8°/70.3°] 64 | 60 | 73° “ [Pt

I—Paratnrms. I]—Dexr Tuicxer. Il—Orzy Woopianp. I1V—Daunr Forast

DISCUSSION OF ECOLOGICAL FACTORS

ECOLOGICAL FACTORS—Continued

TEMPERATURE AND ATMOSPIERE

41

DATE HOUR 4% AIR TEMP. WET BULB. REL. HUM. SOIL METEOROL. ue oa
BM 8 surr.| 1. | sury.| 1a. [sure Im. | T™?-| axy. | winp. :
Sept.14/5-6:00] I |78° |78.2°/66.3°/66° | 53 | 53 | 76° [SS 4.) S.B. | 20cm
“ 14 59 73° i “ “
ri 14 56 75° “cs “ os
“ 14 59 72° ae “ “oe
“15 50 | 74° |SS1..] N. |......
16 Ne f(a Ve a ca ea
“15 BT 1722 1 88 lens
"15 8 lan pee ee eee
Oct. 1 85 | 67° |SS\%| E. | T.
“ 1 90 66° “cc its “
“ce 1 89 68° iy “ oe
“ 1 90 66° “ “ os
“ 2
“ee 2
a 2
“a 2
oe 4
“ 4
i 4
“ee 4
“ 5
“oe 5
“ 5
“ 5
« 6
“ 6
“ 6
“ 6
Nov. 1
“ 1
“ 1
“ Bi
ow Q
“ 2
oc Q
“ 2
ow 63
oe 3
“ 3
os 3
4
4
4
4
5
5
5)
5

42 STUDIES IN THE VEGETATION OF THE STATR

ECOLOGICAL FACTORS—Concluded

TEMPERATURE AND ATMOSPHERE
I—Prarmrs. —Dszpr Toicxer. Ul—Orzsx Woopranp. [V—Drzp Forzssr

; wégatta AIR TEMP. | WET BULB. | REL. HUM. | |, METEOROL.
DATE. | "O07 155 tidied PRECIP,
™ 1Q8) surr.| lm. | surr.| 1m. /sumr.| 1m. “| SKY. | WIND.

sere [OS foceeel CD foes. | OF JOO WH] IN. Joo ceee

STATA IAARAABWA
<ESHSRRH
i
co}
ew
wo
ce}

3
8
oO
ma
mM
x
v4

DISCUSSION OF ECOLOGICAL FACTORS

PHYSICAL WATER-CONTENT

I—Prarrm. [l—Deep Tuicxer. Ul—Orzn Woopianp. IV—Dzrp Forest

43

A ToT, WATEER- PER
DATE TDN aioe Pegeging. | CONTENT OENT

I 18.715 g 14.220 g 4.495 g 24
II 23.570 16.975 6.595 28
OI 20.330 13.490 6.840 34
IV 21.125 14.150 6.975 33

I 17.590 14.800 3.790 22
II 17.645 12,250 5.395 31
Ill 16.945 12.585 4.360 26
IV 20.535 14.915 5.620 27
I 22.790 17.870 4.920 22
II 17.395 11.000 6.395 BY
Il 22.360 16.570 5.790 26
IV 21.205 15.855 5.350 25
I 13.975 12.015 1.960 14
II 19.960 14.600 5.3 0 | 27
I 15.930 12.220 3.715 23
IV 19.455 18.485 5.970 31
I 23.715 18.795 4.920 21
II 18.605 12.375 6.230 33
UI 24.835 17.525 7.310 29
IV 19.850 13.030 €.820 34
I 17.470 15.840 1.630 9
II 19.045 14.935 4.110 22
It 23.170 17.625 6.545 24
IV 18.220 13.945 4,275 23
I 20.7:0 17.890 2.830 14
TI 24.115 16.085 8.030 33
It 21.635 16.435 5.200 24
IV 22.285 15.145 7.150 32
I 18.040 16.550 1.490 8
II 19.585 15.585 4.000 21
Ill | 17.010 13.600 3.410 20
IV 19.145 14.065 5.080 27
I 16.845 16.745 0.100 1
II 18.365 15.665 2.700 15
In 17.865 15.183 2.682 15
IV 17.970 15.580 2.390 13
I 15.365 14.525 0.840 5
sag 14,665 11.515 3.150 4
Im 14.365 13.020 1.345 9
IV 16.965 14.385 2.580 15
I 23.740 17.390 6.350 27
I 21.445 13.835 7.615 36
In 24.085 16.335 7.150 32
IV 24,420 16.275 8.150 33
I 18,720 15.270 3.450 18
Il 19.475 12.645 6.830 35
i 21.115 15.265 5.850 28
IV 21,245 15.855 5.390 2

44

I—Prarriz. I—Dsgep Toioxer. [l—Orsn Woopianp. I1V—Dzep Forusr

STUDIES IN THE VEGETATION OF THE STATE

PHYSICAL WATER-CONTENT—Continued

DATE ron | wsicur | pavina | oowrenr | cuwr

August I 19.615 14,935 g 4.680 g 24
a II 21.415 ? 16.545 4,870 23
te TI | 24.185 18.685 5.500 23
s IV 21.635 15.445 6.190 29
= I 19.020 13.530 5.490 21
a II 22.925 15.185 7.740 34
“ III | 21.360 15.380 5.980 28
ui IV 20.305 13.435 6.870 34
“e I 22.085 18.015 4.070 19
. i 21.770 15.070 6.700 31
a Ill | 21.725 15.150 6.570 30
IV 24.130 17.220 6.910 29
September I 18.600 15.300 3.300 18
ee 22 II 25.045 17.765 7.280 29

_ 19.325 13.835 5.490 28
19.715 13.035 6.680 34

sf 19.700 14.150 5.550 28

< 22.315 16.070 6.245 28

ee 19.755 15.665 4.090 21

ss 24,225 17.815 6.410 26

ae 21.070 16.010 5.060 24
23.295 15.895 7.400 32

ue 23.710 17.970 5.740 24

e 22.375 15.365 7.010 31
October 18.790 15.420 3.370 18
“ 20.095 14.215 5.880 29

oe 18.400 15.400 3.000 16
1 18.475 14.985 3.490 19

ss 17.545 14.515 3.030 WW

o 21.915 16.665 5.250 24
we 19.155 15.965 3.190 1T

ne 17.160 14.030 3.130 18
17.760 14.030 3.730 21

7 20.865 16.535 4.330 21
ies 17.830 14.900 2.930 16
cf 20.485 15.165 5.320 26
November 24,265 18.285 5.980 25
os 23.910 16.860 7.050 29

a 21.415 14.465 6.950 32

mn 28.060 20.820 7.240 26

“ 23.405 17.815 5.590 23
se 26.115 18.925 7.190 28
os 22.585 16.665 5.920 26
ae 21.930 15.600 6.330 29
es 18,680 15.380 3.300 18
ay 21,795 16.645 5.150 24
7 25.360 20.230 5.130 20
ss 22.780 16.630 6.150 at

I—Prarriz. [—Derr Turcxer. U1—Opran Woopianp. IV—Drep Forzst

DISCUSSION OF ECOLOGICAL FACTORS

PHYSICAL WATER-CONTENT—Concluded

45

LOCA- 1G) WATER- PER
DATE hind earane hig oe CONTENT CENT
December 1............ I | 19.%65g | 15.475 g | 4.200g | 2
A eae momen IE | 25.345 20.115 5.740 22
Oh ieee. III | 26.135 20.065 6.070 23
b> AS ec teniceenan IV | 23.305 16.805 6.500 28
Se op ee I | 21.490 16.820 4.600 21
aE Re TI | 23.315 17.535 5.780 25
ME Bawetanaatine TIE | 22.585 17.315 5.270 23
am ene IV | 22.945 17.485 5.460 24

46 STUDIES IN THE VEGETATION OF THE STAT
LIGHT INTENSITY
I—Prarrrse. U—Dzer Taricxer. Ul—Orzen Wooptanp. IV—Derep Forusr
DATE HOURS: | LOOK” SKY CONDITION ieceonaan( | | aanrse
P.M. TION IN SECONDS
rch : I Clear 60 100 '
Mar é II “ 95 62
“ : Til “ 15 80
rr) : IV se 90 ee
April : I Rather hazy 80
vf : II ae 150 40
“ : 1 “a 90 66
“ F IV as 120 50
May : I Clear 50 111
“ A II ee 480 12
as : Til es 160 37
“ P IV ee 420 14
June : I es 48 125
ie : II ss 3900t 1.5
Ke : Tit sf 180 33
“ : IV as 1380 4
ae 2 I *¢ 45 133
ee : iI es 10800 0.5
ee : It sf 240 25
ee : IV “s 1500 4
July : I se 47 128
7 : II sg 11700 0.5
ae ‘ ong #6 210 28
ie : IV as 1020 6
te : I “ 50-45 111
: II ee 11700-11400 0.5
se : Tit ne 270-240 23
us 2 IV iy 1200-1020 0.5
August 20...... 1:00 I ss 53-49 111
as 20s iaseni 1:10 It te 10800-9300 0.5
a 20 ieee 1:20 III se 360-315 16
se 20...... 1:30 IV ss 1350-1110 4
September 8...... 1:00 I Slightly Cloudy 60-53 100
ee Bete 1:10 II ss 6600-6000 0.9
ee Bains 1:20 Til ae 240-210 25
es Sieeues 1:30 IV ss 720-720 8
October 13...... 1:00 I Clear 46-44 133
ce 13......{ 1:10 II “ 600-480 10
1:20 IIt ss 110-90 55
1:30 IV et 347-300 16
1:00 I as 48-48 125
1:10 II ge 140-80 50
1:20 II oe 90-8 ) 66
1:30 IV ae 180-180 33

* For comparison the light on the prairie for March 31 is taken as 100.
7 At the eud of 65 minutes the lines were still visible.

DISCUSSION OF ECOLOGICAL FACTORS 47

The influence of the more important ecological factors upon
the prairie formation is briefly discussed in the following
pages. The prairie upon which the formational work was
conducted lies about three miles west by south of Nebraska
City, along the Burlington railroad. It measures 800 meters
on a side and has an elevation of 305 meters above sea-level.
The highest point is located south of the center on the most
important ridge called, for convenience, Great ridge. This
elevation, which is an extension of higher land lying to the
south, passes north and northeast through the formation,
dividing it into two unequal portions, and terminates
abruptly in the northeast corner of the prairie. In its course
it gradually decreases in altitude and gives off to the north-
west and east secondary ridges of note. The lowest point,
exclusive of the creek-bed, is northwest from the center in
the meadow formation. The difference of elevation between
the highest and lowest points is, by actual measurements, 24
meters.

On the south of this prairie lies the regular section road,
beyond which are cultivated fields; to the east and west also
are culture formations, and a pasture and railroad
bounds the north. A hedge of Torylon pomiferum (osage
orange) forms a dividing line on the east between prairie and
field for 400 meters, and for the same distance on the north
between prairie and pasture. This hedge serves as a basis
for woodland species to gain access to the prairie. —

The surface as a whole gradually inclines to the north
and is rolling, a character due entirely to the erosive action
of water. The slopes of the south are more gradual than
those of the north; likewise those of the east are less abrupt.
than those of the west. South Table creek: flows through:
the northern half of the prairie, cutting off perhaps ten or
twelve hectares from the main body. It enters midway on
the west, meanders east by northeast, and leaves at the north-
east corner. The banks of this creek in many places are
steep, ranging from six to twelve meters high, and generally

48 STUDIES IN THE VEGETATION OF THE STATE

covered with a thicket-like growth of Rhus, Corylus, Cornus,
and, lower down, Salix, scattered here and there with a few
large specimens of Populus. Several ravines of lesser im-
portance flow into this creek from either side. Through the
eastern and the western borders of this prairie, wide draws
pass from the south, tend northward, and empty into Table
creck.* The draw on the west broadens out, as it approaches
the creek, and loses itself, thus giving rise to a typical
meadow formation. On the east, the swale-like draw lies
at the foot of Great ridge and makes possible the one wet
meadow formation, which is in extent 400 x 100 meters. Im-
mediately after excessive precipitation, large volumes of
water from the surrounding region pass through these draws.

The above description, with a careful study of the contour
map, conveys a fairly accurate idea of the prairie formation
under discussion. The extreme diversity of elevation, the
various waterways, and the direction and degree of the nu-
merous slopes and exposures exert a pronounced influence
upon the other controlling physical factors, viz., light, soil
and air temperatures, and water-content. Since physio-
graphical factors, indirectly, produce favorable conditions
for one species and unfavorable conditions for another by
influencing the other physical factors, they are largely con-
trolling in the migration and distribution of species in a
prairie formation, as will be pointed out from time to time.
It can readily be seen that the ecological factors of light, soil
and air temperatures, and water-content exert a far greater
' influence upon this formation than all other physical and
biological factors combined. The crests and southern ex-
posures of ridges maintain maximum soil and atmospheric
temperatures and light, while other slopes, northern and
eastern or western, maintain respectively minimum and
medium temperature and light conditions. Northern slopes
never receive maximum heat and light from the sun; they are

* Table creek for the most part is enclosed for pasture, as the map indicates, and hence
will not appear in the discussion hereafter.

DISCUSSION OF ECOLOGICAL FACTORS 49

the last to recover from a state of winter; their conditions
favoring growth are retarded more by north winds and ac-
celerated less by south winds than those of any other ex-
posure. It is not surprising, then, that we find their pre-
vernal and vernal bloomers 7-17 days behind those of
southern exposures. The soil of crests and steep, exposed
slopes of ridges contains the least amount of water-content
on account of excessive drainage and evaporation; that of
draws and meadow formations the largest amount. Other
things being equal, northern exposures lead all others in
water-content. The more extensive vegetative covering of
the meadow formations as compared with that of the ridges
will undoubtedly exert some infiuence upon soil temperatures
and water-content.

The soil about Nebraska City is largely of glacial origin
overlaid with a rich deposit of loess. It is very porous, dark-
gray in color, and of a light, pulverulent, uniform texture,
particularly rich in organic matter and potash. The general
physical properties of the soil correspond with the character-
istics of sandy loam. Porous soil, especially when sandy,
has a great capacity for water and air. The water falling
upon the surface will largely be absorbed, the water-content
of the soil will be accordingly increased, thus reacting upon
the floral covering, and erosion will be reduced to a minimum.
It is estimated that at least 90 per cent of all water falling
upon this soil is absorbed.

Through the courtesy of J. Sterling Morton, under whose
direction the work was carried on, we are permitted to pub-
lish the following chemical analysis of soil collected about
Nebraska City, made in 1873 by Charles A. Goessmann, Pro-
fessor of Chemistry, Massachusetts Agricultural College.
“The soil lost, when kept over dry calcium chloride, 1.6 per
cent of water; it absorbed, in an air saturated with moisture
at 56° F., 5.04 per cent of moisture; when dried at 212°F.,
it lost 4.05 per cent of moisture; upon being calcined, it lost

4

50 STUDIES IN THE VEGETATION OF THE STATE

18.08 per cent of its weight, consisting mainly of water and
organic matter.

“One thousand parts of the soil treated with 2,000 parts
water produced a solution which left, at 212° to 220° F., a
residue equal to 1.184 parts, which consisted of .414 parts
of ash constituents and .770 parts of organic and volatile
matter.

“One thousand parts of the soil, being treated with hydro-
chlorie acid of 1.12 specific gravity, produced a solution
which contained as follows:

DOtASSOy 34 Hasire eee die eee seni 2.3259 parts
OG ae easier Sees eag ate oreheka Gua sew ares 0.2647 parts
LMC yp tena eea Sole Rea hives 6.4283 parts
MOGNCSIA,. 6. ae gees eval sega ee sea eis 2.7237 parts
Sesquioxide of iron, with traces of

Manganese oxide.............. 44.8332 parts
ATM IANA: 5: 4:6 sree eves a) eae eae 1.4875 parts
Phosphoric acid................... 0.6660 parts
Sulphuric acid.................06. 0.5792 parts

“Quantitative analytical determinations of nitric acid,
ammonia, and organic matter (humus) have not been carried
out.”

ENUMERATION OF SPECIES 51

ENUMERATION OF SPECIES IN THE FORMATION

ELEMENTS PROPER TO THE PRAIRIE FORMATION

Acerates viridifiora ivesii.
A. viridiflora linearis.
Agrostis hiemalis.
Allionia nyctaginea ovata.
Amorpha canescens.
Andropogon furcatus.

A. scoparius.

Androsace occidentalis.
Anemone caroliniana.

A. cylindrica.

Antennaria campestris.
Artemisia gnaphalodes.
Asclepias obtusifolia.

A. syriaca.

A. tuberosa.

A. verticillata.

Aster multiflorus.

A. oblongifolius.

A. sericeus.

Astragalus crassicarpus.
Baptisia bracteata.
Bouteloua curtipendula.
Brauneria pallida.

Carex meadii.

C. pennsylvanica.
Ceanothus ovatus.
Comandra umbellata.
Coreopsis palmata.
Delphinium carolinianum.

Eatonia obtusata.
Eragrostis pectinacea.
Erigeron ramosus.
Euphorbia corollata,
Gentiana puberula.
Helianthus maximiliani,
H. scaberrimus.
Hieracium longipilum.
Koeleria cristata.
Kuhnistera candida.

K. purpurea.

Kuhnia eupatoroides.
Lespedeza capitata.
Laciniaria scariosa.

L. squarrosa.

Linum sulcatum.
Lithospermum canescens.
L. angustifolium.
Meibomia illinoensis.
Mesadenia tuberosa,
Nabalus asper.
Onosmodium molle.
Oxalis violacea.
Panicum depauperatum.
P. pubescens.

P. scribnerianum.

Phlox pilosa.

Physalis heterophylla.

P. virginiana var.

52 STUDIES IN THE VEGETATION OF THE STATE

Polygala verticillata.
Psoralea argophylla.
P. esculenta.

P. tenuiflora.

Rosa arkansana.
Ruellia ciliosa.

Salix humilis.
Senecio plattensis.

S. integerrimus.
Silphium laciniatum.

Sisyrinchium angustifolium.

Solidago memoralis.
8. rigida.

8. rigidiuscula.

S. rupestris.
Sporobolus asper.
S. heterolepis.
Stipa spartea.
Verbena stricta.
Vernonia gigantea.
V. fasciculata.
Viola pedatifida.

, ELEMENTS PECULIAR TO RAVINE, MEADOW, AND SWAMP

Anemone canadensis.
Apocynum cannabinum.
Asclepias incarnata.

A. sullivantii.

Aster paniculatus.
Baptisia leucantha.
Calamagrotis canadensis.
Carex cephaloidea.

C. festucacea.

C. stricta.

C. vulpinoidea.
Chrysopogon avenaceus.
Cicuta maculata.
Cuscuta paradoxa.
Eleocharis palustris.
Elymus canadensis.
Equisetum arvense.

E. laevigatum.
Euthamia graminifolia.
Falcata pitcheri.
Galium tinctorum.
Gyrostachys cernua.

Habenaria bracteata.
H. leucophaea.
Helenium autumnale.
Helianthus giganteus.
H. grosse-serratus.
Juncus tenuis.
Laciniaria pycnostachya,
Lilium canadense.
Lobelia spicata hirtella.
Lycopus americanus.
Lythrum alatum.
Mentha canadensis.
Mublenbergia racemosa.
Panicum virgatum.
Phalaris arundinacea.
Physalis longifolia.
Polygonum emersum.
Oxalis stricta.

Rumex altissimus.
Salix fluviatilis.
Scirpus atrovirens.
Scutellaria laterifiora.

ENUMERATION OF SPECIES

8. parvula.

Silphium integrifolium.
Solidago canadensis.
Spartina cynosuroides.
Steironema ciliatum.
Teucrium occidentale.
Thalictrum purpurascens.

Tradescantia virginiana.
Tripsacum dactyloides,
Verbena hastata.

Vicia americana.

Viola obliqua.

Zizia aurea.

ELEMENTS DERIVED FROM THICKETS AND WOODLANDS

Acalypha virginica,
Aster azureus,

A. levis.

Astragalus carolinianus.
Carduus altissimus.
Cornus asperifolius.
Corylus americana.
Fraxinus lanceolata.
Helianthus tuberosus.
Heliopsis scabra.
Lactuca canadensis.

Meibomia canadensis.
Monarda fistulosa.
Quercus macrocarpa,
Ratibida pinnata,
Rhus glabra.

KR. radicans.
Sambucus canadensis,
Silene stellata.
Silphium perfoliatum.
Teucrium canadense.

ADVENTITIOUS ELEMENTS AND OTHER RUDERAL SPECIES

Acnida tamariscina.
Agrostis alba.
Amaranthus graecizans,
A. torreyi.

Ambrosia trifida.
Cassia chamaecrista.
Chaetochloa viridis.

C. glauca.
Chenopodium album.
Convolvulus sepium.
Euphorbia glyptosperma.
EB. maculata.

E. nutans.

Helianthus annuus.

Iva xanthifolia.

Lactuca canadensis.

L. ludoviciana.

L. pulchella.

Onagra biennis.

Panicum capillare.
Phleum pratense.
Plantago major.

P. rugellii.

Poa pratensis,
Polygonum pennsylvanicum.
Potentilla monspeliensis.
Rumex crispus.

Solanum carolinense.
Trifolium pratense.

T. repens.

54 STUDIES IN THE VEGETATION OF THE STATH

STRUCTURE OF THE FORMATION

Within the limits of this prairie one hundred and eighty-
eight species are noted, of which eighty are elements proper
to the prairie formation, fifty-seven are peculiar to ravine,
meadow, and swamp, twenty-one are elements derived from
woodlands and thickets, and thirty are adventitious or rud-
eral species. When the diversity of the formation is consid-
ered, the facies are relatively few in number. Andropogon
scoparius is the important facies on the slopes and crests of
ridges and is always accompanied by A. furcatus, which
ranks next in importance. Throughout its entire range An-
dropogon scoparius resorts to the “bunch” habit but once or
twice, viz., on steep, exposed, gravelly slopes to the west and
southwest of Great ridge. Everywhere else it plays the role
of a “sod-former,” giving rise to a closed formation. Toward
the foot of ridges and in low prairie, Andropogon scoparius
and A. furcatus become of equal importance. Bouteloua curti-
pendula and Kocleria cristata are also facies. I*requently
Bouteloua does not blossom, in which case it is likely to be
confused with Andropogon. Stipa spartea becomes a
facies in but one location in low prairies, where for a few hec-
tares it is almost exclusive. In the meadow formation, Andro-
pogon furcatus attains its maximum in size and numbers. In
some stationsit becomesthesole facies; again it shares equally
with two tall-growing meadow grasses, Chrysopogon avena-
ceus and Panicum virgatum. Panicum is controlling in the
wetter parts of the formation, in the beds of draws, etc. Spar-
tina cynosuroides occurs in meadow formations sparingly
scattered throughout, never in numbers sufficient to rank as
an important facies. In the wet meadow formation Hlcocharis
palustris covers the ground with a dense carpet-like layer
during May and June. This is soon hidden from view by the

STRUCTURE OF THE FORMATION 55

taller-growing Carez stricta and C. cephaloidca, and later by
Spartina cynosuroides which frequently attains a height of
three meters.

The distribution, alternation,” and zonation of some of the
more important species are worthy of note. Comandra um-
bellata commonly occupies crests and exposed slopes of
ridges, where it often numbers 2,000 to the quadrat. Coman-
dra is not continuous, however; it disappears entirely for a
time, reappearing in greater numbers than before. Coreopsis
palmata and Aster multiflorus inhabit crests of ridges and
high prairies. These two species occur in copious, definite
patches, which frequently alternate. The individuals of a
patch are most numerous toward the center, frequently 2,500
to the five-meter quadrat, and gradually diminish in size
and number as the margins are approached. The above spe-
cies are rarely found in controlling numbers in the same quad-
rat; the one or the other ranks as copious 1, the remaining
ones being subordinate. Aster multiflorus also frequents
meadows, ‘where it forms rather definite patches of robust in-
dividuals. Alternation of species is beautifully shown in the
case of Kuhnistera purpurea and K. candida. The explana-
tion is evident. The former species is much more of a xero-
phyte and almost invariably grows on crests of ridges and
abrupt or exposed slopes. About midway up the ridge, these
two species are of equal importance, while a little lower down
the white-flowered form will have almost completely displaced
K. purpurea. Kuhnistera candida is a taller-growing plant
and possesses a greater leaf surface than K. purpurea. Ac-
. cordingly, it is not as well adapted to xerophytic conditions.
The distribution of the blazing-stars is also largely dictated
by the water-content, and if these plants were as abundant as
Kuhnistera, conditions at least as striking would obtain.
Laciniaria squarrosa is found on crests of high ridges, a typi-

*Alternation is here used in the sense in which it has been employed by Dr. Clements, f.e.,
to apply to succession in space of species and formations, though alternation of species is
alone concerned in this place. The term “succession” is applied by the same authority to the
phenomenon of succession in time.

56 STUDIES IN THE VEGETATION OF THE STATE

cai xerophyte reduced in size of leaf surface. JL. scariosa
frequents low prairies and extends about half way up the
ridges, while L. pycnostachya is a tall species, invariably in-
habiting meadow formations. Baptisia bracteata and B. leu-
cantha arrange themselves in concentric zones, ten to thirty
meters wide, about draws and meadows and about ridges.
The taller, glabrous form, B. leucantha, always occupies the
moister zone, and it is seldom that one finds individuals of the
one species within the zone of the other. B. bracteata is fre-
quently found half way up the slopes. Hrigeron ramosus
finds the most favorable conditions on the tops of ridges and
southern exposures. Huphorbia corollata is a gregario-copi-
ous plant, found mostly on ridges and slopes. It gradually
diminishes in numbers as the foot of the ridge is approached,
and hardly occurs at all in meadow formations.

Certain thicket and open woodland species have established
themselves in the prairie and meadow formation. Among
these are Aster azureus and A. levis, two gregario-copious,
rosette-forming species, which thrive abundantly in low prai-
ries. Corylus americana has gained a foothold at several lo-
cations in the formation, particularly near the creek and
hedges. This species takes up its characteristic thicket
growth, which makes possible the migration of such woodland
forms as Ratibida pinnata, Silene stellata, Acalypha virgin-
ica, Helianthus tuberosus, Monarda fistulosa, and Heliopsis
scabra. The invasion of Corylus in a prairie formation clear-
ly demonstrates its superiority of occupation over the prairie
species. With Corylus also are found a few specimens of
Sanbucus canadensis, Cornus asperifolia, Rhus glabra, Quer-
cus macrocarpa, and Fraxinus lanceolata.

Of the ruderal species the aianthous Cassia chamaecrista
is the most conspicuous during its flowering period, as well as
the most important in numbers. To the south along the sec-
tion road, Cassia has pushed into the prairie formation twen-
ty-five to thirty-five meters, and in many places the prin-
cipal and secondary species have been crowded out; even the
facies are subordinated, and to find them one has to look be-

STRUCTURE OF THE FORMATION 57

low the dense mass of yellow and green. In the vicinity of
old stock yards, Cassia immediately takes full possession of
the denuded areas. Helianthus annuus and Ambrosia trifida
attain considerable prominence along the wet meadow for-
mation and in roadside ditches. Parts of the wet meadow
formation from which the grass is cut several times during
the year afford suitable location for such plants as Plantago
major, P. rugellii, Trifolium pratense, T. repens, and Poa
pratensis. Helianthus grosse-serratus and H. giganteus,
though not ruderal species, have found home-like conditions
on the banks of a ditch extending the entire length of the wet
meadow formation.

SPECIES OF THE PREVERNAL FLORAL ASPECT

Principal Species
Carex pennsylvanica. Antennaria campestris.

Secondary Species

Androsace occidentalis. Salix humilis.
Anemone caroliniana. S. fluviatilis.
Equisetum arvense. Corylus americana.

THE PREVERNAL FLORAL ASPECT

The earliest prevernal bloomers of the prairie formation
appear on the southern slopes of the higher ridges during the
first or second week in April. Of the four species proper to
the formation, one, Carex pennsylvanica, not infrequently
ranks as a facies, and the others, Anemone caroliniana, An-
tennaria campestris, and Androsace occidentalis, occur as
copious or gregarious species. Carer pennsylvanica is a xero-
phyte, forming patches or mats several meters in extent on
slopes or crests of ridges; toward the middle of April these
patches are rendered noticeable by the yellow and purple
of the numerous small spikes. Carex pennsylvanica also oc-
cur in low meadows, where if grows with reduced numbers,
and blossoms about a week later, for which reason it never as-

58 STUDIES IN THE VEGETATION OF THE STATS

sumes.the same importance as in the higher situations. This
early spring sedge is perennial by virtue of its rootstalks and
stolons. The flowers of C. pennsylvanica are proterogynous,
macrobiostigmatous, and allogamous. The stigmas are borne
below the longistaminate anthers, and if xenogamy fails geit-
onogamy may thus obtain.

The blue and white ddisy-like flower of Anemone carolint-
ana appear with or soon after the first yellow spikes of Carex
pennsylvanica, and when abundant they present a striking
contrast with the faintly green sward. A. caroliniana is also
a xerophyte and a frequenter of southern slopes and crests ;
its bulbous root explains its prevernal appearance. The pol-
len is protected by the corolla-like sepals, which open at 8:30
A.M. and close at 4:30 P.M., remairing closed on cloudy days.
Fertilization is allo-autogamous. If allogamy is not secured
by visiting insects, which are by no means abundant at this
time, autogamy is sure to result with the closing of the flower
parts, as the anthers are brought in direct contact with the
stigmas. Last year, flowers excluded from all insects were
fertilized, and matured seeds.

Andresace occidentalis is in all respects one of the smallest
and most inconspicuous of our flowering plants. Androsace
appears on high ridges about one week before Anemone, and
were it not for the massing of its individuals, the plant might
easily pass unnoticed. Although Androsace is hapaxanthous,
it is wonderfully stable in the formation, since it occupies the
same ridge year after year. So far as observed, the plant has
no direct means of dissemination, hence its infrequent
distribution but copious numbers. The plants begin growth
in the autumn, forming a very smal] but closed rosette, which
passes the winter in excellent condition, and, during the
first warm days of spring, sends up a slender stalk bearing
a cluster of flowers. The inconspicuous, gamopetalous corol-
las are constricted immediately above the point of attach-
ment of stamens to the corolla, which serves to keep
the pollen dry. In case allogamy fails, it would seem that

STRUCTURE OF THE FORMATION 59

mychogamy might insure autogamy. Nevertheless it is to be
observed that only a small percentage of ovaries is fertilized.

Antennaria campestris, the one mat-forming species of our
prairies, is a frequenter of high and low prairies and mead-
ows, though, from a standpoint of numbers, finding its most
favorable conditions in the low prairies. The prairie everlast-
ing appears with the other prevernal bloomers, being from ten
days to two weeks earlier on southern than on northern ex-
posures. The plant is stoloniferous, which character ren-
ders it highly gregarious; this latter habit, together with its
white woolly apearance, makes it one of the most conspicuous
elements of the prevernal aspect. Anthesis in this species, as
in other prevernal bloomers, is closely followed by matura-
tion. The elongation of the scape is simultaneous with the
spreading of the pappus, which causes the achene to become
free from the receptacle. The general distribution of the
species over the prairie is evidence of the perfect dissemina-
tion secured through the agency of the wind. The above spe-
cies, though beginning to blossom during the prevernal pe-
riod, mostly continue during the early vernal, and frequently
appear more prominent during the vernal than the prevernal
aspect. This is especially the case with Antennaria, since the
mats are more prominent during the period of maturation
than during anthesis,

The other prevernal bloomers need only bare mention. A
few bluish-gray cones of Hquisetum arvense are found dotted
here and there in the meadow formations during the latter
half of the prevernal period. Salix humilis, a xerophilous
woody shrub, one to two meters in height, occurs at one sta-
tion in the prairie. Its short catkins of dioecious flowers are
observed on the first or second day of April; these flowers
are frequented by bees and flies which undoubtedly
assist in pollen transfer. The swamp willow, Salix fluviatilis,
is found in the meadow formation near the creek, especially
in those parts flooded during the spring time. It is to be
looked upon as an intruder. The swamp willow is about two

60 STUDIES IN THE VEGETATION OF THE STATE

weeks later then the prairie willow, S. humilis. The distri-
bution of Corylus americana, the hazel nut, has already been
given. The flowers of this species are anemophilous and ac-
cordingly allog2mous; the copious, powdery pollen is pro-
duced in pendulous aments, protection being afforded by the
expanded bracts. It is well known that blue jays, crows,
and squirrels look after the dissemination of the hazel nut.
A blue jay will easily crowd four to eight of these nuts in his
throat and thus carry them from one place to another.

ELEMENTS OF THE EARLY VERNAL FLORAL ASPECT

Facies (Wet Meadow Formation)

Carex stricta. Eleocharis palustris.
Carex cephaloidea.

Principal Species

Comandra umbellata. Carex vulpinoidea (wet mea-
Baptisia bracteata, dow).
Secondary Species

Astragalus crassicarpus. Scutellaria parvula.
Carex festucacea. Senecio integerrimus.
Carex meadii. S. plattensis.
Fragaria virginiana. Sisyrinchium angustifolium.
Lithospermum angusti- Vicia americana.

folium. Viola obliqua.
Lithospermum canescens. Viola pedatifida.

DISCUSSION OF THE EARLY VERNAL FLORAL ASPECT

The facies of the prairie formation do not contribute to
the general aspect and need not be considered now. The
sedge meadow facies are Carex stricta, C. vulpinoidea, and
Bleocharis palustris. Carex stricta alternates with Spartina
cynosuroidcs in the sedge meadow formation, occupying the
wetter portions, where, with. C. vulpinoidea, it forms a close,

STRUCTURE OF THE FORMATION 61

permanent sod, which resists largely the encroachment of
other species. The lower purple spikes contrast with the
upper yellow staminate ones and form a conspicuous element
of the aspect. The copious pollen of the much exserted sta-
mens is cither transferred by means of the wind (xenogamy),
or showered down upon the receptive stigmas, which are
proterogynous and macrobiostigmatous, in such masses as to
color them yellow. In the latter case geitonogamy results.
Eleocharis palustris is a hydrophytic rootstalk plant, by
means of which it occupies a considerable area of the wet
meadow formation, over which it forms a dense carpet-like
covering. This plant is inconspicuous in every respect and
soon hidden from view by the taller sedges. Carex vulpinoidea
does not form definite patches, but is dispersed through the
wet meadow formation. It is at least two weeks later than
C. stricta; its dull-colored spikes do not contribute to the
general aspect, even though the plant is later and more robust.
Carex cephaloidea occupies the margins of the wet meadow
formation at a few stations, but at no place is it prominent.
Comandra umbeliata is the one copious species in the early
vernal aspect of the prairie formation. Its general distribu-
tion has already been given. Comandra is a small, rather in-
conspicuous, pale green plant with umbels of greenish-white,
odorless flowers, and were it not for the aggregation of its
individuals and its blossoming at a time when the floral cov-
ering is almost destitute of color, it would produce little ef-
fect in the fioral aspect. As it is, the bastard toad-flax is lost
sight of before it has completed anthesis. Comandra is per-
ennial by means of rootstalks, a fact which explains its habit
of growing in patches. It is a typical xerophyte. In four-
teen quadrats, including various exposures of Great ridge,
its numbers range between 400 and 1,900 individuals, the
average being 1,000 per quadrat. It is the most abundant of
the principal species within the limits of its distribution. The
anthers, at least, of the newly opened flowers are frequently
in contact with tke stigmas by inflection of the filaments, the

62 STUDIES IN THE VEGETATION. OF THE STATE

pistils elongating as they become older. Very few ovaries be-
come fertilized.

The large bright blue blossoms of Viola pedatifida appear
about a week later than those of V. obliqua, and, when min-
gled with the yellow of Lithospermum and of Carex meadit,
give a typical vernal effect. Viola pedatifida is one of
the most evenly distributed of our prairie species. It is found
on all of the slopes, crests of ridges, and to some extent in
the meadow formations. The greatest number found in any
quadrat is forty-two, and the average for seventeen quadrats,
for all except northern exposures, is twenty individuals. On
northern slopes two to twelve plants were growing in each
quadrat examined. Viola pedatifida, V. obliqua, and others
of the genus have developed short, thick, fleshy rootstalks, by
virtue of which they are enabled to secure an early start in
the spring. I have not observed that rosettes of Viola pass the
winter months. Viola pedatifida is chasmo-cleistogamous,
but so far as observed few chasmogamous flowers are fertile.
The cleistogamous flowers are usually developed later and
are quite productive. The chasmogamous fiowers are herko-
gamous, and inclined so as to receive no water upon the
pollen. The bright colored petals are folded and bearded,
apparently to protect the pollen. Dissemination is brought
about in the various violets by the closing together of the
walls of the valves of the ovary in drying.

Oxalis violacca frequents low prairies and meadows, where
it forms circular, carpet-like patches of green and rose 2-4
meters in diameter. Ovxalis has also established itself along
southern exposures of hedges, growing profusely in dense
carpets 15-25 meters in extent. The wood sorrel is perennial
by means of a scaly bulb, which explains its early appearance.
It is one of our prettiest vernal bloomers, appearing at a time
when the floral covering is sparse. Its flowers are hemeran-
thous and usually ephemeral, opening at 7:30 a.M., and clos-
ing at 5:30 p.M., remaining closed on cloudy days. The flower
pedicels are refiexed before and after anthesis. The filaments

STRUCTURE OF THE FORMATION 63

and styles are reciprocally of two lengths (heterodistyly),
xenogamy alone being possible.

Carex meadii frequents low prairies and meadows. Its in-
dividuals are somewhat aggregated on account of rootstalk
propagation. Its bluish green leaves and large, yellow stam-
inate spikes appear where there is little else to relieve the
monotone left by winter. Carex mceadii does not occur widely
distributed, nor does it exceed copious 4 in abundance. ‘The
copious pollen of the exserted stamens is borne above the pis-
tillate spikes, and matures before the stigmas are receptive
(proterandry). Allogamy, consisting of xenogamy or geito-
nogamy, results. Sisyrinchium angustifolium, a grass-like
plant in appearance, occurs typically in low prairies, but is
also found in meadows. Its “bunch” habit, causing the small
blue and white flowers to be aggregated, renders it conspicu-
ous, especially since it appears before the facies play any
part in the aspect. The flowers of Sisyrinchium are herko-
gamous, the stigmas projecting beyond and alternating with
the extrorse anthers, and hemeranthous, opening at 8 A.M.
and closing at 5:30 p.m. They remain closed on cloudy days.
It is to be noted that almost every ovary is fertile. Senecio
integerrimus is conspicuous on account of being represented
in the formation by one individual.

Senecio plattensis is met rarely in the low prairies. Its
numerous bright yellow heads, especially when the individu-
als are semi-aggregated, as is usually the case, are conspicu-
ous objects of the early vernal period. Wind dissemination
obtains by means of the copious pappus. Both Senccio plat-
tensis and S. integerrimus produce open rosettes through
the agency of which these plants secure greater recognition on
account of blossoming earlier.

Fragaria virginiana haunts low prairies and meadows,
where, on account of numerous runners, it forms rather defi-
nite patches, of which two or three are observed in the forma-
tion. Fragaria forms open rosettes, the inner silky leaves of
which are covered over with the broad stipules of the outer

G4 STUDIES IN THE VEGETATION OF THE STATD

leaves, thus passing the winter unharmed. The perfect
rosette conditions explains the appearance of the clusters of
white flowers during the last week of April. Dissemination
is secured through animal agency, by virtue of the color and
taste of the fruit. Lithospermum canescens is sparsely dis-
tributed over the entire prairie, most abundantly, however,
in low prairies, where it averages one or two individuals per
quadrat. The throat of its hypocrateriform corolla is par-
tially closed by projecting folds or sinuses. The nectar-bear-
ing flowers are heterodistylous, the stamens and stigmas being
separated by nearly the length of the corolla tube, xenogamy
always resulting. <A visiting insect carries pollen from the
high stamens of one plant to the high stigma of another, and
from the low stamens to the low stigmas. Dioecism practic-
ally obtains, with the advantage that no plant is unfruitful.
Lithospermum angustifolium has about the same distribu-
tion as the above species, but it occurs only now and then, and
is a rare plant in the formation. In L. angustifolium the tube
of the nectariferous corolla is much elongated, at least in
earlier flowers, and its throat is entirely closed with the prom-
inent appendages. The pollen is thus well protected from
insect enemies and excessive moisture. Allogamy results,
but the means are not clear. The later cleistoramous flowers
of this species are much more fertile than the earlier chasmo-
gamous ones. These two species, even with sparse numbers,
brighten the prairie with their shades of yellow and give a de-
cided tone to the aspect. Of the two plants, L. canescens is
the more conspicuous on account of its bright colors and its
almost leafiess, compactly flowered racemes. The flowers of
LL. canescens are also very fragrant. Both of the puccoons
are perennial by deep, thick roots, from which the stems
sprout up very early in the spring. Plants of L. angusti-
felitwm frequently pass the winter in the rosette condition.
The most striking plant of the vernal aspect is Baptisia
bracteata, which begins blossoming during the first week in
May and continues for about twenty days. Itsmassiveracemes

STRUCTURE OF THE FORMATION 65

of showy, cream-colored flowers, too heavy to be sustained
by the plant, are strewn over eastern, western, and southern
slopes, sometimes extending almost to the crests of ridges.
It is normally a low prairie species, as is shown by its distri-
bution. As to duration, it is perennial, and its average is
about one individual for three or four quadrats. The strong
papilionaceous corolla admirably protects the pollen from
rain and admits of fertilization by means of bumble bees only.
As the bee’s head is thrust far into the flower to reach the
nectar, the keel and wings of the corolla are forced down, thus
uncovering the incurved stamens and styles, and bringing the
anthers and hairy stigma into direct contact with the abdo-
men of the bee. Since the bee has no means of determining
whether nectar is present, except by trying, the flowers are
visited many times during the day and thus allogamy is se-
cured. Upon examination, I found the abdomens of several
bees colored yellow with the abundant pollen masses. Astrag-
alus crassicarpus is found at only one station in the prairie,
viz., on the western slopes of Great ridge near the south side.
It is a low prairie species tending toward xerophilous condi-
tions. The purplish blue racemes of the ground plum appear
at a time when there is little else in the floral covering, hence
the important part they play. The low, reclining stems
spread from the perennial, woody root in all directions, a
single individual frequently occupying considerable space.
Vicia americana is a rootstalk plant and finds its favorite
liaunts in meadows near streams and woodlands. This plant
grows at a few locations in the meadow formation near the
creek, where it occupies rather definite patches. Its climbing
habit renders all the more conspicuous the numerous showy
racemes of purplish and light blue flowers, so that a patch
may be recognized at a distance of twenty to forty meters.
During the month of May, Vicia dominates the floral aspect
within its limited range. Patches of Vicia are the favorite
resorts of bumble bees, fertilization being accomplished as

§

66° STUDIES IN THE VEGETATION OF THE STATE

for Baptisia. Carex festucacea frequents meadows, where it
occurs as a secondary species. It adds little to the floral
aspect. Allogamy is secured in pollination by means of pro-
terogynous stigmas. Scutellaria parvula, a small herb, per-
ennial by means of tuberous rootstalks, occurs rarely in the
meadows. Scutellaria is scarcely noticeable, owing to the
denser meadow facies which soon overtop it. Viola obliqua
is a hydrophyte, occurring as a secondary species in the sedge
meadow, and meadow formations. Its flowers are chasmo-
cleistogamous, the cleistogamous ones being abundantly
fertile.

ELEMENTS OF THE LATE VERNAL FLORAL ASPECT

Facies

Koeleria cristata. Stipa spartea.
Panicum scribnerianum.

Principal Species
Ceanothus ovatus.

Secondary Species

Agrostis hiemalis. Panicum depauperatum
Allionia nyctaginea P. pubescens.

ovata. Phlox pilosa.
Anemone canadensis Physalis virginiana var.
Asclepias obtysifolia. Psoralea esculenta.
Calamagrostis canaden- Rosa arkansana.

sis. Rumex altissimus.
Delphinium carolinianum. R. crispus.
Eatonia obtusata. Tradescantia virginiana.
Galium tinctorum. Trifolium pratense.
Juncus tenuis. T. repens.
Onosmodium moile. Tripsacum dactyloides.

Oxalig stricta. Zizia aurea.

STRUCTURE OF THE FORMATION 67
THE LATE VERNAL ASPECT

Many of the plants of the early vernal period continue
throughout the late vernal aspect, so that this division is one
for convenience rather than otherwise. The facies of the
prairie formation are represented by three sod formers,
Panicum scribnerianum, Stipa spartea, and Koeleria cristata,
all of which occur throughout the prairie, but only in locali-
ties become of sufficient importance to rank as facies. Koe-
leria is most abundant on the higher slopes and crests of
ridges, Stipa and Panicum in the lower prairies and mead-
ows. Panicum averages twenty to twenty-five bunches per
quadrat, Stipa from five to fifteen, and Koeleria, when pres-
ent, twenty to twenty-five. Panicum is the first of the vernal
facies to blossom, closely followed by Koeleria and Stipa. The
fiowers of all are anemophilous and belong to the Longistam-
ineae; as would be expected, the stigmas are plumose and
exserted. Ceanothus ovatus is a xerophytic shrub occupying
the exposed tops of the various ridges. Where most abun-
dant, it controls to a considerable extent the numbers of the
secondary species. Ceanothus cccurs in every count made
upon the crest of Great ridge, ranging from three to twenty-
nine individuals to the quadrat. When we remember that a
singie shrub of redroot contains from five to sixty woody
stems, some of which are branched, we get some idea of the
dominating influence it exerts. During May and the early
part of June, the crest of Great ridge is white with the in-
numerable panicled flowers of this plant. Two xerophytes,
Panicum pubescens and P. depauperatuwm, occur as small,
tufted perennials on Great ridge and some exposed slopes.
P. pubescens is the less abundant and is easily recognized by
its villous appearance and its smaller spikelets. Panicum de-
pauperatum is frequent, averaging about six bunches per
quadrat throughout its range. Neither of these grasses con-
tributes anything of note to the vegetative covering. Hatonia

68 STUDIES IN THE VEGETATION OF THE STATB

obtusata occurs only sparsely and infrequently on the ridge,
and also on the low prairies.

Rosa arkansana is a low bush two to five decimeters in
height, frequenting high prairies and slopes. At times it
tends to become gregario-copious; at other times its individ-
uals are scattered rather evenly over the formation. The rose
averages twelve to fifteen individuals to the quadrat, which
number may be doubled under more xerophytic conditions, or
reduced to one or two plants in meadows. The prairie rose
begins anthesis during the late vernal period and continues
throughout the estival aspect. Its large pink or white frag-
rant blossoms are among the more conspicuous objects of the
early summer aspect, especially when slightly raised above
the surrounding prairie, as is the case when the plant grows
on slopes. The flowers open at 5:30 a.M., lasting for one or
two days. One of the most deceptive of the prairie species,
so far as numbers are concerned, is Physalis virginiana. On
a walk over the prairie, even with careful examination, one
seldom sees more than half a dozen individuals; however, the
plant is found in almost every quadrat throughout meadow
and prairie formation, sparsely, or more rarely as subcopious
2. It is needless to say the groundcherry adds nothing to the
tone of the aspect. The plants are small, one or two deci-
meters high, and perennial by fleshy rootstalks. Allionia
nyctaginea ovata was discovered at only one station, viz., on
Great ridge. In duration, it is a perennial. The flowers are
nyctanthous, opening at 4:30 P.M., and closing at 9:00 a.M.,
and ephemeral, except on cloudy days. If allogamy is not
secured through the agency of “night flyers,” the much ex-
serted filaments and style become refiexed, frequently de-
scribing one or two complete circles and bringing anthers and
stigmas together. Autogamy may thus obtain. Asclepias
obtusifolia is a solitary plant occurring only rarely on the
higher prairies throughout its distribution. Its many-flow-
ered, mostly solitary umbel of greenish-purple blossoms is
raised above the surrounding vegetation by means of a long

STRUCTURE OF THE FORMATION 69.

peduncle. The plant is a perennial. Only a few specimens
of Onosmodium molle were found within the prairie. Unless
several stems grow from the perennial root, as is usually the
case, these shaggy plants with greenish white clustered flow-
ers pass unnoticed.

Psoralea esculenta is noted as a sparse plant on the slopes
of Great ridge and to a limited extent on low prairies. The
plant body, which is clothed with white villous hairs, hardly
contrasts with its densely flowered spikes of grayish-blue
flowers. This peculiarity, with the solitary habit of the
plant and the overtopping facies, renders it quite obscure.
P. esculenta is perennial by means of large tubers. During
July the stem becomes freed from the caudex and rolls about
over the prairies, thus disseminating the seeds. Delphinium
carolinianum is recorded at one location in rather low prai-
ries. The appearance of the slender, showy racemes of white
flowers indicates the close of the vernal and the beginning of
the estival period. The individuals are not numerous enough
to contribute to the general aspect. From various observa-
tions made, the bumble bee appears to attend to pollination,
which is in general similar to that of Baptisia bracteata.
When ripe the follicles open at the top, thus allowing the
seeds to scatter gradually. Tuberous clustered roots render
the larkspur perennial. Agrostis hiemalis occurs only now
and then in meadows, especially where the formation is some-
what open. Unless abundant, the fine, hair-like bunches are
hardly noticeable. The plant is perennial by means of rosette-
like tufts of crowded linear leaves which pass the winter
nicely. During early summer the lax panicles containing the
ripened seeds are rolled about by the wind.

Galium tinctorum is a weak stemmed, much branching,
rootstalk plant frequenting wet meadows and ravines, where
it forms a layer beneath the tall facies. At times Galium
becomes controlling in small areas, in which case it develops
an almost impenetrable carpet. This bedstraw is of little
prominence in the formation from any standpoint. Anemone

79 STUDIES IN THE VEGETATION OF THE STATE

canadensis is a perennial mesophyte, occurring at a few sta-
tions in draws and ravines, and having the same distribution
as Galium tinetorum. Toward the middle of May the large
white blossoms of Anemone begin to appear and continue for
about a month. Phlox pilosa is a perennial mesophyte found
sparsely in meadows. Its cymes of bright pink or purple
fragrant blossoms, with now and then a white flowered indi-
vidual, lend a decided tone to the floral aspect. The hypo-
crateriform corolla is nectar-bearing and the stamens are un-
equally inserted upon its tubes above the style. If allogamy
is not secured through insect visitors, autogamy may result
from pollen falling upon the receptive stigmas. On account
of its grass-like leaves, Phlox practically disappears with the
close of anthesis. Yradescantia virginiana is noted only
sparsely at a few stations in the meadow formation. These
plants develop from perennial roots, and during the vernal
period produce bunches of showy blue, pink, or purplish flow-
ers. On account of its semblance to the facies, the plant dis-
appears with the close of anthesis. Another pleiocyclic spe-
cies occurring with sparse or subcopious abundance through-
out meadow formations is Zizia aurea. This plant begins blos-
soming about the middle of May and continues for a month,
varying the aspect with yellow here and there.

Tripsacum dactyloides is found at one of two stations
along the margins of the sedge meadow, becoming occasion-
ally quite controlling. Its coarse leaves and stems, together
with its monoecious flowers, easily distinguish it from any
other grass in the prairie. The flowers are proterandrous
and xenogamous, the long, roughened stigmas appearing
after the stamens. In maturation the upper spikes ripen
first and with that portion of the rhachis drop off, and thus
are carried away with the first flood. Yripsacum is peren-
nial with very thick, woody rootstalks,

Calamagrostis canadensis is a hydrophilous, rootstalk
pleiocyclic growing in small clumps in the wet meadow.
During the flowering period these clumps are especially con-

STRUCTURE OF THE FORMATION G1

spicuous on account of the plumose stigmas and the much
exserted anthers.

Rumez crispus and R, altissimus occur sparsely, the one
within the wet meadow, the other about its margins. Both
Species owe their very early start in the spring to their thick-
ened perennial roots, as the loose rosettes formed by these
plants do not withstand the winter. The numerous, green,
inconspicuous, pendulous flowers of these docks are polyg-
amo-monoecious and anemophilous; geitonogamy and xenog-
amy accordingly result. The least movement of the plant
envelops the flowers with a cloud of pollen. The three valves
or wings, which are commonly grain-bearing, enable the
achene to float, which explains the distribution of these plants
along water ways. If these valves are removed, the achenes
sink. The remaining species of the vernal aspect need only
brief mention. Juncus tenuis frequents a few places in the
wet meadow, as a rather inconspicuous, grass-like perennial.
Ovalis stricta forms an interrupted layer below the tall facies,
in parts of the wet meadow and meadow formations. During
the fall Oxalis forms small, compact mats, which, in protected
situations, pass the winter in good condition. The yellow
flowered oxalis is one of the first plants to begin growth in
the spring. Trifolium pratense and T. repens are growing
in the drier portions of the wet meadow. 1. pratense forms
open rosettes which, with protection, frequently withstand
the hardships of winter.

ELEMENTS OF THE EARLY ESTIVAL FLORAL ASPECT

Facies
Same as for vernal aspect.

Principal Specves

Amorpha canescens. Kuhnistera candida,
Ceanothus ovatus.* K. purpurea.
Coreopsis palmata. Meibomia illinoensis,

Erigeron ramosus.
* Extending into this aspect from the vernal.

72 STUDIES IN THE VEGETATION OF THE STATE

Secondary Species

Acerates viridiflora ivesii. Lilium canadense.

A. viridiflora linearis. Lythrum alatum.
‘Agrostis alba. Mesadenia tuberosa.
Anemone cylindrica. Oxalis stricta.*
Amaranthus graecizans.; Phalaris arundinacea.
Apocynum cannabinum. Phleum pratense.
Asclepias sullivantii. Physalis heterophylla,
A. syriaca. Physalis longifolia.

A. tuberosa. Plantago major.

A. verticillata. P. rugellii.

Astragalus carolinianus. Polygala verticillata.
Baptisia leucantha. Potentilla monspeliensis.
Brauneria pallida. Psoralea argophylla.
Chaetochloa viridis. P. tenuiflora.

C. glauca. Rosa arkansana.*
Chenopodium album. Ruellia ciliosa.
Convolvulus sepium. Scirpus atrovirens.
Equisetum laevigatum. Solanum carolinense.
Euphorbia glyptosperma. Steironema ciliatum.
E. nutans. Teucrium occidentale.
KE. maculata. T. canadense.
Habenaria leucophaea. Thalictrum purpurascens.
Lactuca pulchella. Verbena stricta.

The estival period begins about the tenth of June, and is
characterized by the rapid diminution of the vernal bloomers
rather than by the addition of the important estival flowers.
The physical factors are changing rapidly and in most cases
approaching their maximum. The floral covering accord-
ingly undergoes a complete change. The white flowers of
Ceanothus ovatus continue on the ridges in maximum num-
bers, but the white-rayed flowers of the more frequent and
equally abundant Hrigeron ramosus render them of second-
ary prominence. Bright yellow patches of Coreopsis palmata
"+ Extending into this aspect from the verna

STRUCTURE OF THE FORMATION 73

are found on every ridge and slope. Before these flowers have
reached their maximum numbers, three other showy bloomers,
Amorpha canescens, Kuhnistera purpurea, and K. candida
are added, and the estiva) aspect attains its maximum in color
and complexity.

No new facies appear during the early estival aspect.
Frigeron ramosus occurs principally on ridges and slopes
where it averages 15-18 individuals to the quadrat, also to
some extent in low prairies and meadows. In the latter situ-
ation it occurs sparsely, and its flowers are not conspicuous
owing to the denser facies. The flea-bane is dicyclic and
forms mcderately close rosettes, which secure for it an early
start in the spring and a nearly uniform distribution. Wind
dissemination is brought about by means of the pappus.
Kuhnistera candida, K. purpurea, and Amorpha canescens
are both frequent and copious, occurring in varying numbers
in every quadrat. The abundance of Kuhnistera candida, K.
purpurea, Amorpha canescens, and Coreopsis palmata in
quadrats I-X XII is as follows:

QUADRAT.| LOCATION. | EXPOSURE. | K, CANDIDA. |K. PURPUREA. es cae ©. PALMATA.
I Low ..... West .... 643 28 AD) ieee eayenae
If Crest Ridge. 7 51 128 1416
Ill “4 CEs Viale ae 12 150 138 593
IV |Low..... North TID) | [ais cians eo) Chisaeeoka se
Vv Se Samniend West 81 3 ee eerreecnrice rs
VI ere Hast ..... 190 49 Bin Vaiveeercas
VII | Ridge....| North... 10 1032 23 1100
VIIL | Crest ....| Ridge... 10 176 10 375
Ix Ridge 14.|8. E...... 225 476 42 5
x Byer cs Sagas 482 360 8 | resae divers
XI Crest South .. 4 163 134 129
XII ee .| Ridge.. 5 425 | 326 900
XII | Ridge 14.|8.E...... 169 10 495 125
XIV ie el North az.|ex sexeades 575 OO™ | iswteseeecnisis
XV ee ee 115 75 92 86
XVI es West 32 116 325 206
XVII | Base..... fs 20 19 J42° oluitoenucaee
XVIII | Crest a [INE Wee staves 4 34 500 190
XIX | Base..... GE nina 356 8 88 137
XX _ | Crest North. 9 18 3 1100
XXI as N.W..... 7 119 26 178
XXII | Base..... North 45 16 180 7

TA STUDIES IN THE VEGETATION OF THE STATE

Kuhnistera candida ranges from 150-600 individuals to the
five-meter square in the low prairies, averaging 250-275, and
from 4-45 individuals on the ridges and exposed slopes. In-
dividuals of K. purpurea number 150 to 1,000 to the quadrat
in the higher prairies about Great ridge and 5-50 in the low
prairies. The average of the plant under normal conditions
is about 350 to the quadrat. The prairie clovers are peren-
nial, so that their distribution in the formation is rather per-
manent and dictated perhaps wholly by the water-content,
since conditions frequently obtain where the two species oc-
cur in equal numbers. The showy white or purple flowers of
these species are arranged in compact cylindrical spikes; an-
thesis begins from below, extending upward over a zone of
about one centimeter daily. The Kuhnisteras have proter-
androus, pollen flowers, the stamens of which become exserted
during the morning hours (5:00-7:00 a.M.) and disappear
very soon, while the styles elongate in the afternoon or on the
following morning. Allogamy, xenogamous or geitonoga-
mous, obtains through insect agency. The orange anthers of
K. purpurea produce copious masses of globose, roughened
pollen cells covered with a yellowish viscin. On high prairies
Amorpha canescens ranges from 125-500 individuals per
quadrat, averaging perhaps 300, while on low prairies from
12-50 plants are counted in the five-meter plot. Its abun-
dance is sparse to subcopious in meadows. The leadplant or
shoestring is a low undershrub controlling by virtue of its
deep-seated, woody roots, which eminently fit it for xerophy-
tic conditions. The leaves and stem of this plant are lead-
colored, and when the terminal, clustered blue racemes ap-
pear it becomes one of the most conspicuous plants in the
aspect. The flowers are proterogynous and accordingly allo-
gamous. The yellow anthers with red filaments are exserted
during the early morning hours and by noon have mostly dis-
appeared.

‘creopsis palmata occurs in definite patches on Great
ridge, ranging from 200-1,400 individuals per quadrat, the

STRUCTURE OF THE FORMATION 15

number depending largely upon the location of the quadrat
within the Coreopsis patch. During June these masses of
yellow-rayed bloomers contrast sharply with the other mostly
white and blue flowers. The plants are perennial; root prop-
agation obtains, hence the patches. Brauneria pallida is a
xerophyte with thick, black rocts and rigid stems and leaves.
It invariably occurs on high prairies and ridges, where it
averages 25-30 individuals to the quadrat. Brauneria begins
blossoming during the first week of June and continues for
over a month. The spreading rose rays surround a cone of
brown and altogether produce a pretty effect. These flowers
are easily recognized at a distance of fifty meters. Acerates
viridifiora linearis and A. viridiflora ivesit are two typical
xerophytes of Great ridge. Both are perennial, solitary
plants, recognized only with difficulty in the floral covering
on account of the uniform color of flowers and leaves. Their
follicles containing comose seeds mature September 1.
Anemone cylindrica is neither frequent nor abundant, oc-
curring only at a few stations on Great ridge. It is a per-
ennial xerophyte. The few greenish-white, unattractive
flowers appear during the first or second week of June, last-
ing for a few days only. The ragged heads are common on the
prairies during July and August, the woolly achenes of which
are carried by gophers to their burrows.

The tuberous-rooted Indian plantain, Mesadenia tuberosa,
is a rare plant in the low prairies. The stems are at least one
meter high and terminate with a showy, white corymb easily
distinguishable for 200 meters. Verbena stricta occurs oc-
casionally in low prairies and meadows. Its hairy, rigid
stems, bearing terminal racemes of blue flowers, grow from
perennial roots. The curved salver-form corolla includes the
didynamous stamens which exceed the style (herkogamy).
When the insect, usually one of the Hymenoptera, is securing
the nectar, he is quite sure to leave pollen of some other ver-
vain flowers upon the stigma, allogamy resulting. It is to be
noted that V. stricta is rather abundant in a pasture of two

16 STUDIES IN THE VEGETATION OF THE STAT

years’ duration, joining the above meadow formation. The
same is likewise true for V. hastata and Vernonia gigantea,
all three of which possess a bitter juice, rendering them dis-
tasteful to stock. Polygala verticillata is a frequent, but
sparse, inconspicuous annual of low prairies and meadows.
It adds nothing to the floral covering nor to the aspect.
Ruellia ciliosa is a low, hairy perennial occurring sparsely at
a few stations in low prairies, where it aggregates in loose
patches. The beautiful lilac-colored flowers are ephemeral,
opening during the night and falling away by 12:00 mM. They
scarcely contribute to the floral aspect on account of the
taller facies. Flowers of Ruellia ciliosa are funnel-form,
with a long tube, at the base of which is secreted the nectar.
The period of anthesis lasts for sixty days. Psoralea argo-
phylla is a low, branching perennial of moist prairies, where
it assumes a gregarious habit. Its characteristic white stems
and leaves render patches of this plant conspicuous objects
of the aspect. On high prairies it is usually loosely inter-
spersed throughout and hence never noticeable. The small,
blue flowers do not add to the plant. After maturation, the
plant becomes freed from the caudex and rolls about on the
prairies as a tumble-weed. Psoralea tenuiflora is found at a
few stations in low prairies and meadows. It is a rather
tall, diffusely branched perennial, conspicuous on account
of its many small spikes of blue flowers, which continue for a
month or more.

Asclepias verticillata occurs as a subcopious plant through-
out low prairies and meadows. Its individuals are hardly
distinguishable from the facies until the small umbels of
white flowers appear. The small milkweed is perennial.
Maturation begins during the latter part of August, at which
time the follicles burst, setting free the comose seeds. Ascle-
pias tuberosa is a rare plant in the low prairies. Its mostly
clustered stems proceed from thickened perennial roots and
terminate with conspicuous, orange-red umbels which are
among the brightest objeci.. of the aspect. It is to be noted

STRUCTURE OF THE FORMATION we

that very few of the ovaries become fertile. Maturation be-
gins September 1, dissemination occurring as for A. verticil-
lata. Asclepias syriaca and A. sullivantii are frequenters of
low prairies, meadows, and draws, where they occur only
rarely; the latter species prefers the wetter situations. A.
syriaca also grows in cultivated fields, wastes, and along bor-
ders of thickets. The tall, leafy stems, bearing numerous
umbels of purplish flowers, are striking objects in the forma-
tion. These flowers continue for twenty-five to thirty days,
during which time they are visited frequently by the red-
brown milkweed butterfly (Danais archippus). Dissemina-
tion is the same as for other milkweeds.

The distribution of Baptisia leucantha has already been
indicated. The plant is found but sparsely in low prairies
and meadows; nevertheless it is a conspicuous element of the
floral aspect. The erect stems develop from a perennial root
and are crowned with a long, loosely flowered raceme of
cream-colored flowers, which continue during June, After
anthesis these plants give the appearance of miniature trees
scattered throughout the formation. Tertilization obtains
through the agency of bumble bees and is in all respects as
for B. bracteata. The inflated pods mature during the latter
part of July, but give no clue to methods of dissemination.
Meibomia illinoensis, a tall, rigid, branching perennial, one to
two meters high, abounds at a few stations in the low prairies,
meadows, and draws. It ordinarily averages 25-60 individu-
als to the five-meter plot; however, in one quadrat 672 plants
were enumerated. In this particular case, Meibomia has be-
come a controlling element in the formation, either crowding
out or subordinating the secondary species. The long raceme
of light blue flowers is especially noticeable during the
morning hours. The easily separable loments are bristly
uncinate-pubescent, and adhere to any surface with which
they come in contact. Lythrum alatum inhabits ravines,
draws, and wet meadows. It usually grows in definite
crowded patches, in which few secondary species are found,

78 STUDIES IN THE VEGETATION OF THE STATE

and hence the greater prominence it derives. Its period of
anthesis lasts about sixty days, during which time its numer-.
ous purple flowers give a characteristic coloring to the
patches. The flowers are heterodistylous and accordingly
xenogamous; the insect, in securing nectar from the base of

the calyx tube, carries the pollen from the long stamens to

the long pistil, etc. Steironema ciliatum occurs in draws
with Lythrum alatwm and at one or two stations in the

meadows. It isa rootstalk plant, by means of which it forms
rather definite patches. Steironema is not abundant enough
to be of importance. Teucrium occidentale and T. canadense
are inhabitants of low meadows and draws, in which situa-

tions their individuals become aggregated. T’. occidentale is

also sparsely scattered through the sedge meadow formation.

The two species frequently grow in the same patch, the type
specimens of each, however, being recognized at a glance.

Neither species is abundant enough to add materially to the
formation or the aspect.

Habenaria Icucophaea, Thalictrum purpurascens, and
Inalium canadense are frequenters of low meadows and ravines
where they occur sparsely. The showy spikes of white frag-
rant fiowers of Habenaria are conspicuous objects in the
vegetation, though never abundant enough to give color to
the aspect. Xenogamy or geitonogamy results from insect
pollination. The nectar is secreted in large quantities in the
very elongated spur of the lip. The insect, in order to reach
the nectar, (of necessity an insect with a long proboscis)
brings his head or proboscis in contact with a viscid disc,
to which are attached the two pairs of pollinia. These pol-
linia adhering to the head parts are thus torn away from the
flower and stand a good chance of coming in contact with
the broad stigmatic surfaces of the succeeding flowers, to
which they readily adhere if the stigmas are receptive, i. e.,
covered with very adhesive viscin. The above is practically
what obtained when these flowers were exposed to “night
flyers.” On account of the resemblance to the facies, the

STRUCTURE OF THE FORMATION 79

leafy plants are scarcely observed after flowering. The white
fringed orchis is perennial by means of thick, fibrous roots.
Habenaria bracteata is a rare, inconspicuous plant found
only once in the meadows. Thalictrum purpurascens is a
leafy, tall-growing perennial, the numerous male plants of
which are especially prominent in the aspect during anthesis.
At this time the staminate racemes are one mass of yellow,
linear anthers, which give off a cloud of “pollen dust” at the
least movement. The flowers are anemophilous and dio-
ecious, xenogamy alone being possible. By far the mest
showy flower in the entire prairie is Lilium canadense. Its
erect, leafy stems are about one meter high and terminate
with a single large, nodding blossom, bright orange in color
and beautifully spotted with brown. The lily is perennial
by means of scaly bulbs developed from a short, stout root-
stalk. Equisetum laevigatum is one of the two fernworts of
meadows, H. arvense being the other. HH. laevigatum occurs
at two stations in the low meadows, and ranges from 44-260
individuals to the quadrat. Its dark green, jointed stems are
hardly to be distinguished from the coarser facies. Hquise-
tum is a perennial with deep-seated rootstalks, from which
frequently many stems develop.

Scirpus atrovirens and Phalaris arwndinacea are hydro-
philous species of the wet meadow. Scirpus develops short
rootstalks, by virtue of which it forms dense clumps a few
meters in extent. The dark green foliage and the brown
umbels render the clumps of this species prominent in mead-
ows. The flowers are proterogynous, allogamy being the pre-
ferred method of pollination. Phalaris is a tall-growing per-
ennial grass, forming rather indefinite bunches of several
dozen individuals. Anthesis takes place during June and is
immediately followed by maturation. The seeds are soon
thrashed out of the dry panicles with the wind. Scirpus
atrovirens and Phalaris arundinacea are almost invariably
associated with Cicuta maculata, Asclepias incarnata, and
Lythrum alatum. Apocynum cannabinum occurs sparsely

80 STUDIES IN THE VEGETATION OF THE STATE

in meadows and swamps. Its clusters of white flowers ap-
pear about June 1 and continue for forty days. The Indian
hemp is a perennial with deep, thick roots, from which propa-
gation results; hence its tendency to form clumps. Dry,
grassy banks of streams are the favored haunts of A. cannabi-
num. Dissemination is as for the milkweeds. Physalis longi-
folia is a tall, bushy perennial inhabiting mostly the Carex
facies of the wet meadow. It averages four to ten individu-
als per quadrat.

The remaining plants of the early estival fioral aspect are of
importance principally because of their presence. They
neither add to the aspect nor the floral covering. With per-
haps one exception, Physalis heterophylla, which occurs
rarely throughout the prairie, all are ruderal or adventitious
species. Agrostis alba, Phleum pratense, and Poa pratensis
form a zone a few meters in width on the west of the wet
meadow. Plantago major and P. rugellii occur in the drier
parts of the wet meadow. They are perennial plants with
short, thick rootstalks, forming open rosettes which “freeze
out” during the winter. The flowers of these plantains are
aianthous, anemophilous, proterogynous, and xenogamous.
The long, exserted stamens appear several days after the
stigmas. Potentilla monspeliensis is a dicyclic herb growing
below the tall, wet meadow facies. It forms open rosettes,
the inner leaves of which are protected with the broad stip-
ules and bases of the outer ones.

During excessive precipitation, soil from neighboring cul-
ture formations is transported to parts of the sedge meadow.
These deposits are soon covered over with a dense growth
consisting of such ruderals as Solanum carolinense, Lactuca
pulchella, Chaetochloa viridis, C. glauca, Chenopodium al-
bum, Amaranthus graecizans, and Convolvulus sepium. The
common tumbling weed, Amaranthus graecizans, and also
the following spurges, Euphorbia glyptosperma, E. nutans,
and H#. maculata, grow abundantly on the mounds in the

STRUCTURE OF THE FORMATION &1

prairie made by the pouched gopher. After some time the
encroaching facies again claim the ground.

ELEMENTS OF THE LATE ESTIVAL FLORAL ASPECT
Facies

Bouteloua curtipendula.
Principal Species

Euphorbia corollata. Kuhnistera purpurea.
Kuhnistera candida. Meibomia illinoensis.
Secondary Species
Amaranthus torreyi. Mentha canadensis.
Asclepias incarnata. Meibomia canadensis,
A. verticillata. Polygonum pennsylvanicum.
Astragalus carolinianus. Panicum capillare.
Cassia chamaecrista. Ratibida pinnata.
Cicuta maculata. Silphium laciniatum.
Convolvulus sepium. S. integrifolium.
Elymus canadensis. S. perfoliatum.
Heliopsis scabra. Solidago rupestris.
Hieracium longipilum. Scutellaria lateriflora.
Laciniaria squarrosa. Teucrium canadense.
Lactuca canadensis. T. occidentale.
L. ludoviciana. Verbena hastata.
Lespedeza capitata. V. stricta.
Linum sulcatum. Vernonia fasciculata.
Lycopus americanus. V. gigantea.

Lythrum alatum.

The late estival floral aspect is set off here in order to
note more accurately the gradual changes in the floral cov-
ering. It is not considered an aspect complete in itself but
rather a division of one. Like the late vernal aspect, it is
a period of transition. Bouteloua curtipendula is the only
new facies, and its distribution has already been noted.
Kuhnistera purpurea, K. candida, and Meibomia illinoensis,

6

82 STUDIES IN THE VEGETATION OF THE STATE

respectively, continue in diminishing numbers in the higher
prairies, the low prairies, and the meadows, and pass out
entirely with the advent of the serotinal period. The grayish-
white plants of Amorpha canescens are still conspicuous ob-
jects on ridges, though long past anthesis. They give the
floral covering a “ragged” appearance. Ceanothus ovatus
is represented now by a mass of low, leafy bushes, abundant
on ridges and scattered here and there on the higher slopes.
The white flowers of Hrigeron ramosus and the bright yel-
low of Corcopsis palmata have disappeared entirely from
the formation, and their places have been taken by the taller
and more prominent Huphorbia corollata, the flat-topped
flower clusters of which are conspicuous on every ridge and
slope. Others that lend coloring to the aspect are Laciniaria
squarrosa on ridges, Solidago rupestris in high and low prai-
ries, Silphium laciniatum in low prairies and meadows, S.
integrifolium and Vernonia gigantea in low meadows, and
Cassia chamaccrista in locations heretofore given.

Euphorbia corollata occurs, with two exceptions, in every
quadrat from JI-XXII. It averages 50 individuals to the
five-meter square, though in several instances more than
twice that number have been counted. H. corollata is prom-
inent in this formation, not alone on account of its size, over-
topping as it does all other species within its patch, but also
because of its advantageous distribution and gregario-copi-
ous disposition. The strict stems are about one meter high,
clothed with bright green leaves and crowned with large,
white, flat-topped umbels. This milk spurge is an aianthous
bloomer; its flowers appear about the middle of June, in-
creasing in numbers until August 1, after which time they
gradually diminish. The stems and leaves are not eaten by
stock on account of the milky juice they contain, a property
which gives the plant a decided advantage in pastures. The
plant is perennial by means of long rootstalks.

Laciniaria squarrosa is a xerophyte of the crest of Great
ridge, occurring rather infrequently. It ranges from 6-55

STRUCTURE OF THH FORMATION 83

individuals to the quadrat with an average of 18 (subcop. 1).

The short spikes of bright purple flowers render the plant

prominent in the late floral aspect. Dissemination is by

means of the plumose pappus. Solidago rupestris frequents
low prairies and especially slopes; it is found to some extent
in xerophilous situations. The individuals of this species,

in the various quadrats examined, range from 2-275, with

an average of 45. The plants are copio-gregarious in the

lower prairies, frequently forming patches 1-3 meters in

extent, while in the more xerophilous situations they are

often loosely dispersed throughout. S. rupestris forms rather
open rosettes, which tend toward the closed type; it is also

a rootstalk plant, which partially explains its gregarious

habit. S. rupestris is among the earliest of the goldenrods

to blossom and the only estival one in the formation. Its

bright yellow flower clusters, especially when aggregated,

are among the more conspicuous objects of the aspect. The.
achenes are modified for wind dissemination. Linum sul-

catum is a small, slender annual occurring frequently but
sparsely throughout the prairie, its average for sixteen quad-
rats for all conditions being five individuals. It is interesting

to note that in quadrats XXI and XXII (see map) both

with northern exposures, Linum averages 40 individuals,
(subcop. 1). The bright yellow ephemeral corollas open at
4:00 a.M., and fall off between 10:00 and 11:00 a.m. Dis-

semination results from the capsules splitting open from
above when dry, thus scattering the seeds.

Hieracium longipilum is a sparse or subcopious perennial
of low prairies. The plant is not abundant enough to be of
importance to the covering. Hieracium forms rather close
rosettes, the leaves of which are densely covered with brown-
ish, bristly hairs 1-2 cm. long. Silphium laciniatum is a
tall, coarse perennial growing sparsely in low prairies and
to some extent on the crest of Great ridge. It is a promi-
nent feature of the formation on account of its extreme size
(2 meters) and the large, yellow flowers. Its laciniate leaves

84 STUDIES IN THE VEGETATION OF THE STATE

are arranged with reference to morning and evening light.
Lespedeza capitata is a strict, silky-canescent perennial oc-
curring infrequently in low prairies and meadows. In quad-
rats I, II, and IV of low prairies and meadows it averages
55 individuals, while in quadrats XXII, XXIV, XXV, and
XXVII of low meadows it averages but three. When abun-
dant it becomes rather a prominent factor in the floral cover-
ing on account of its size, color, and aggregation of plants.
The capitate clusters of small flowers do not add to the prom-
inence of the plant in the aspect. JL. capitata is also an in-
habitant of high, dry prairies and bluffs along the Missouri
river.

Silphium integrifolium and Vernonia gigantea are two
tall, leafy perennials of low meadows and edges of sloughs.
In such situations the iron-weed ranges from 15-65 individ-
uals per quadrat and the rosin-weed from 15-100. Silphiwm
frequently grows in dense impenetrable clumps which empha-
size all the more its prominence. These two species form
a zone about 30 meters wide in the wet meadow, and similar
zones in other parts of the formation. In these zones Sil-
phium invariably occupies the inside, next to, but never in-
vading, the Spartina facies, while Vernonia begins about the
middle and extends in diminishing numbers to the outside,
where it ends in scattered bunches. During July and Au-
gust these zones are prominent features in the formation,
from the masses of yellow flowers of Silphium within, and the
purple flowers of Vernonia without, the two colors blending
at the center. V. gigantea occurs abundantly in low pastures,
frequently in company with V. fasciculata.

Two hydrophytes, Cicuta maculata and Asclepias incar-
nata, occur sparsely in the sedge meadow. The large, leafy,
robust individuals of C. maculata tend to grow in groups;
its numerous white-flowered umbels continue during July
and are in striking contrast with the rose-purple of the
swamp milkweed. Both plants are perennials, the water
hemlock developing fleshy tuber-like roots. Another inhab-

STRUCTURE OF THE FORMATION 85

itant of the sedge meadow, though not a hydrophyte, is Ver-
nonia fasciculata, a plant growing mostly throughout the
Carex facies. A few plants of Lycopus americanus, Mentha
canadensis, and Scutellaria lateriflora are also scattered
through this formation. The taller, overtopping facies ren-
der them hardly discernible. All are perennial amphibious
plants, by means of suckers or stolons.

Ratibida pinnata, Lactuca canadensis, Meibomia cana-
densis, Heliopsis scabra, Silphium perfoliatum, and As-
tragalus carolinianus are typically frequenters of thickets,
open woodlands, and grassy banks of streams. With the ex-
ception of Lactuca canadensis, which is a dicyclic, all are
pleiocyclic herbs. Ratibida pinnata occurs at but a few sta-
tions in the prairies near the creek. Under such conditions
it hardly ever blossoms and is of no consequence in the forma-
tion. <A few individuals of Lactuca canadensis are found in
the sedge meadow and in low prairies. The wide dissemina-
tion of the achenes of the wild lettuce explains its presence.
L. canadensis and L. ludoviciana develop rosettes, the leaves
of which are mostly killed during the winter months. Jfei-
bomia canadensis is found near the creek or hedges, where
it forms rather dense clumps of individuals. During anthe-
sis these clumps are especially prominent on account of the
crowded, terminal racemes of purple flowers. Heliopsis
scabra occurs at a few stations in the meadows. It has the
appearance of a small sunflower. The square stems and
connate leaves of Silphium perfokatum render individuals
of this species noticeable in any formation. A few straggling
plants of the square-stemmed rosin-weed are found in the
meadows. Astragalus carolinianus also grows in meadows.
Its large racemes of greenish-white flowers are rendered less
noticeable on account of the many other brighter colored
forms. Astragalus is one of the first plants to begin growth
in the spring, in spite of its late flowering period.

The remaining six species, Amaranthus torreyi, Convol-
amlus sepium, Cassia chamaecrista, Lactuca ludoviciana,

86 STUDIES IN THE VEGETATION OF THE STATE

Panicum capillare, and Polygonum pennsylvanicum are
adventitious or ruderal elements. With one exception, Convol-
vulus sepium, which is perennial by rootstalks, all are hapa-
xanthous herbs, Lactuca ludoviciana being dicyclic. Con-
volvulus sepium is an inhabitant of the meadows, where it
averages about 30 to the quadrat. The large, white flowers
of the bindweed are conspicuous objects among the facies,
the vines being mostly hidden from view. Amaranthus tor-
reyi and Polygonum pennsylvanicum occur sparsely in the
wet meadow. Panicum capillare grows on the mounds of
the pouched gopher. With the close of maturation, the glo-
bose panicle becomes free and rolls about over the prairies.
Cassia chamaecrista is undoubtedly an intruder from the
section road. It is also found in quantity along the eastern
margins of the wet meadow. During maturation the pods
split open, thus exposing the seeds for dissemination.

ELEMENTS OF THE SEROTINAL FLORAL ASPECT

Facies
Andropogon scoparius. Elymus canadensis.
A. furcatus, Panicum virgatum.
Bouteloua curtipendula. Spartina cynosuroides. :

Chrysopogon avenaceus.
Principal Species
Aster multiflorus. Helianthus seaberrimus.

Secondary Species

Aster levis. Carduus altissimus.

A. azureus. Cuscuta paradoxa.

A. paniculatus. Euthamia graminifolia.
A. oblongifolius. Lespedeza capitata.

A. sericeus. Laciniaria pycnostachyae
Artemisia gnaphalodes. L. scariosa.

Ambrosia trifida. Lygodesmia juncea.

Acalypha virginica, Muhlenbergia racemosa.

STRUCTURE OF THE FORMATION 87

Monarda fistulosa. H. tuberosus.
Nabalus asper. Helenium autumnale,
Polygonum emersum. Kuhnia eupatorioides.
Eragrostis pectinacea. Solidago rigida.
Falcata pitcheri. S. rigidiuscula.
Gentiana puberula. S. nemoralis.
Gyrostachys cernua. S. canadensis.
Helianthus maximiliani., Sporobolus asper.

H. annuus. S. heterolepis.

H. grosse-serratus. Vernonia fasciculata.
H. giganteus. V. gigantea.

The serotinal period begins during the last days of July
and continues with a gradual diminution of bloomers until
the close of the flowering season. Its arrival is made known
by the blossoming of such species as Solidago rigida and S.
nemoralis in the high prairies and S. canadensis and Lacin-
taria pycnostachya in the meadows. New species continue
to be added until the 15th of September, Aster azurcus, A.
levis, and Solidago rigidiuscula being among the last. After
September 10, the decrease of bloomers in the aspect is very
noticeable, the field being left entirely to the asters, golden-
rods, blazing stars, sunflowers, and ironweeds. These au-
tumnal bloomers secure the same recognition in the floral
covering as the vernal bloomers, by analogous means, i. e.,
’ appearing late in the year rather than early, when there is
little else of prominence in the floral covering. During the
early serotinal period the vegetative layer is extremely com-
plicated, since many of the estival flowers persist for a time,
besides sporadic aianthous bloomers. Of the forty-seven
bloomers of the period, twenty-eight are species of the Com-
positae. Accordingly, the aspect from beginning to end is
preeminently a composite one, the yellow of the goldenrods
and sunflowers being varied with the blue and white of the
asters and the purple of the blazing stars and ironweeds. It
is interesting to note that one-half of the serotinal species

88 STUDIES IN THE VEGETATION OF THE STATE

secure wind dissemination directly by means of rolling pani-
cles, pappus modifications, etc.

The distribution of the facies having been taken up in the
structure of the formation needs no further comment here.
It should be noted, however, that in the higher prairies the
Andropogons form a low, scanty herbaceous covering with
only here and therea culm. In the meadows, on the contrary,
the forked heads of Andropogon furcatus, the close panicles
of Chrysopogon avenaceus, and the bearded spikes of Hlymus
canadensis* control the aspect. The large, purplish pani-
cles of Panicum virgatum are observed toward the center of
draws and in moist parts of meadows. Since these are all
tall grasses and generally closely aggregated, there is little
to be seen of the few, mostly over-topped, secondary species;
with one exception, Hlymus canadensis, these grasses are
rootstalk formers and all are pleiocyclic. The Andropogons
and Chysopogon enjoy, at least to some extent, dissemination
by means of the wind. Spartina cynosuroides is controlling
only in parts of the wet meadow where its tall, coarse culms
(14-3 meters) are noticeable on account of their size. The
slough grass is perennial with thick, scaly rootstalks.

Aster multiflorus is present, with two exceptions, in every
quadrat from I-XXVII; 275-300 is perhaps a fair average,
but not infrequently as many as 2,000 individuals may be
enumerated within the five-meter square. The dense, white
flowered aster is normally a xerophyte, but it also occurs
in low prairies and meadows and with nearly the same abun-
dance as in the higher situations; in the latter, however,
the patches are usually of greater extent and the individuals
more hirsute and reduced in size and leaf surface. As would
be expected, the patches are hardly at all noticeable until
anthesis, when they give to the floral covering a character-
istic white color for almost two months. Aster multiflorus
is perennial by rootstalks and also develops small, rather
closed rosettes.

*Elymus canadensis is an eatival bloomer referred to this place for convenience.

STRUCTURE OF THE FORMATION 89

Helianthus scaberrimus is a gregario-copious or subcopious
xerophyte of Great ridge. It grows mostly in patches of con-
siderable extent, though frequently occurring sparsely for
some distance, especially in low prairies. The rigid, scabrous
stems, often much reduced on the ridge, attain a height of 3-
14 meters and terminate with a few long-pedunculate, con-
spicuous, yellow and purple heads, about the middle of July,
and continue until October 1, during a portion of which time
patches of these plants contrast sharply with the surrounding
floral covering. Helianthus maximiliani grows at a few places
along the slopes of the ridge; the individuals are usually low,
gregarious, and grayish-canescent. The dwarf, few-flowered
plants of this species growing in xerophytic conditions are
in striking contrast with the tall, robust, many-flowered in-
dividuals of more favorable circumstances. H. maaximiliant
and H. scaberrimus are perennial by thickened rootstalks.

Of the three xerophytic goldenrods, Solidago rigida, S.
rigidiuscula, and S. nemoralis, all frequenters of the ridge,
the first is the most frequent and also the most abundant,
occurring in eighteen out of twenty-six quadrats with an
average of 12-15; the second is found in nine quadrats out
of twenty-six with an average of five individuals; the third,
S. nemoralis, is found at only a few stations on the ridge
and northern slopes near the creek. Solidago rigida is dis-
tributed rather evenly throughout its range and during its
flowering period. The rigid, coarse stems, crowned with a
dense, yellow corymb, are conspicuous objects of ridges and
slopes. The bitter juice of the stem prevents the plant from
being eaten, and hence we find this species one of the com-
monest of the “pasture weeds.” <A few leaves at the base of
the stem usually remain green through the winter, which
means, perhaps, the beginning of a rosette. The most showy
goldenrod in the prairies is S. rigidiuscula; its terminal ob-
long heads, usually 5-20 from one root, appear with the last
flowers of the serotinal period and continue for a month or
more, during which time they are the most showy of the gold-

90 STUDIES IN THE VEGETATION OF THE STATE

enrods of high prairies and bluffs. Solidago nemoralis, the
least of our goldenrods, is one of the most beautiful; the
ashen-gray plants are gregario-copious, a few to several hun-
dred yccurring in a patch. The dull purplish stems termi-
nate with large, one-sided, sparsely branched panicles, which
render groups of this plant very noticeable. It goes without
saying that the goldenrods are perennial. The latter plant,
S. nemoralis, also develops closed rosettes from near the
base of the old stem, which present the appearance of a rudi-
mentary mat. Aster oblongifolius and A. sericeus are xero-
phytes of Great ridge; the latter species, A. sericeus, is con-
spicuous in the formation throughout its period of growth
on account of its silvery white, silky pubescence, and,
though the two species enjoy the same distribution, fre-
quence, and abundance, A. oblongifolius is rarely seen except
during anthesis. The flowers of both species are large (2-3
em. broad) with numerous violet-purple or light blue
rays surrounding a disc of yellow, and are in striking
contrast with the sear brown or greenish brown prairie
facies. The individuals of both species tend to become loosely
aggregated; both are perennial and frequently form small
closed rosettes.

Other xerophytes or species with xerophilous tendencies
are Laciniaria scariosa, Kuhnia eupatorioides, Lygodesmia
juncea, Sporobolus asper, 8. heterolepis, and Eragrostis pec-
tinacea. Laciniaria scariosa is a xerophilous species of Great
ridge, with a very strong tendency to grow in low prairies,
where it becomes more robust and abundant. In the thirteen
quadrats, representing varied conditions, in which the plant
occurs, it maintains an average of seven individuals; how-
ever, in certain locations of the low prairies fifty plants have
been counted within the five-meter square. The hemispheric
heads of rose-purple flowers are produced on long, strict ra-
cemes, and so far as coloring the aspect is concerned this
plant ranks equally with the asters and goldenrods. The
blazing stars are perennial by means of tubers. Kuhnia

STRUCTURE OF THE FORMATION 91

eupatorioides inhabits high prairies and to some extent mead-
ows; it is, however, of a xerophytic tendency. Kuhnia occurs
in seventeen quadrats out of twenty-seven for all locations,
with an average of five individuals. When seen from a dis-
tance, especially upon ridges, the plant has a characteristic
bush-like appearance, owing to the numerous leafy stems
proceeding from the same perennial root. The greenish,
terminal flower clusters are of secondary note in the aspect;
nevertheless the abundant whitish pappus renders the plant
prominent during maturation. Lygodesmia juncea is an in-
conspicuous xerophilous perennial of Great ridge, occurring
only rarely. It belongs properly to the summer aspect. On
account of its wiry stems and linear leaves the plant is rarely
seen among the facies. Sporobolus asper and S. heterolepis
are two pleiocyclic grasses sparsely distributed over Great
ridge, neither one being abundant enough, however, to add
to the floral covering. It is interesting to note that a xero-
phyte like Sporobolus asper should have obtained a foothold
along the southern border of the wet meadow and become
almost controlling for fifty meters or more in extent. Hra-
grostis pectinacea also is found on Great ridge, but more
especially on the lower slopes; in addition to this it is a fre-
quenter of roadsides. It grows in definite bunches which
are not recognized until the large purplish panicles appear.
The plant is never abundant enough to add color to the as-
pect. During maturation the panicles become free and roll
about as for Panicum capillare, thus dispersing their seeds.
Gentiana puberula is a rare and infrequent inhabitant of
low prairies. Its rather short, leafy stems, mostly clustered
from perennial roots, produce, during September and October,
the few large, bright blue flowers. Gentiana puberula, Aster
sericeus, A. oblongifolius, and Solidago rigidiuscula are
among the last bloomers of the year. From various observa-
tions made, the flowers of Gentiana are undoubtedly proter-
_, androus, insect pollination obtaining. Artemisia gnapha-
lodes is normally a xerophyte; its stem and leaves are covered

92 STUDIES IN THE VEGETATION OF THE STATE

over with a dense, woolly coat, thus greatly reducing evapora-
tion. However, in this formation the species is growing in
the meadows near the sloughs. The white tomentose char-
acter renders the patches prominent in the floral covering.
The mugwort is pleiocyclic, root propagation obtaining.
Nabalus asper is an infrequent plant of low prairies and
meadows. The erect stem, bearing the numerous heads of in-
conspicuous flowers, proceeds from a tuber. Seedlings of this
plant pass the winter in a rosette condition.
Gyrostachys cernua is a frequenter of meadows and draws
where it occurs sparsely. It has practically the same distri-
bution and abundance as Liliwm canadense, Habenaria leu-
cophaea, and Lobelia spicata hirtella. The small spikes of
white flowers are seen only with difficulty, since they appear
at a time when the facies equal or overtop them. It is curi-
ous to note that some individuals of this species have been
found on the crest of Great ridge, others in the wet meadows.
This orchis, as for Habenaria leucophaea, is perennial with
fleshy-fibrous roots. Huthamia graminifolia is found in
draws near the south end of the prairie. The grassy-leaved
stems are not easily recognizable until the flat-topped, yel-
low flower cluster appears. The plants are perennial by long
rootstalks. Laciniuria pycnostachya occurs in meadows as
a sparse to subcopious plant. Its tall, erect stems, usually
in clusters of two to five, terminate with a showy, purple
spike (20-40 cm. long) which easily makes the plant the
most striking of its time. Where a number of the plants are
found together the facies is tinged purplish. The stems are
clothed with grass-like leaves, the surfaces of which are ar-
ranged for the milder light of morning and evening. The
plants are perennial as in L. scariosa. Solidago canadensis
is an inhabitant of edges of woodlands, meadows, and draws
—the latter especially: where erosion is taking place. As
rapidly as the facies are dislodged, S. canadensis, Helianthus
grosse-serratus, and H. giganteus push in and oceupy the
apace. When growing in draws, S. canadensis forms rather

STRUCTURE OF THE FORMATION 93

small but definite patches. The yellow flowers of these three
species in draws, and of the goldenrod in meadows, color the
autumnal meadow aspect. S. canadensis is perennial with
rootstalks, and is also a rosette former. Helianthus grosse-
serratus and H. giganteus are frequenters of banks of
streams, draws, ditches, etc. It has already been stated that
these two flowers occupy almost completely the banks of a
ditch extending the length of the sedge meadow; in this loca-
tion, however, H. annuus grows with them, all three giving a
bright yellow to the eastern margin of the slough. H. grosse-
serratus and H. giganteus are perennial by fleshy roots and
rootstalks.

Helenium autumnale and Polygonum emersum are two
hydrophilous inhabitants of low wet meadows. Helenium
is pleiocyclic and occurs sparsely at a few locations in the
sedge meadow. In the meadows P. emersum is diffused
through the facies, as a sparse or subcopious plant, never at-
taining much size, nor blossoming, while in the sedge
meadow it forms a dense clump or patch from which all
other species are excluded, and which during anthesis be-
comes scarlet from the many flower spikes. Polygonum
persicaria is perennial with horizontal, creeping rootstalks.
Aster paniculatus is a low meadow inhabitant frequently
growing in hydrophilous situations. It is found in four
quadrats out of six in the sedge meadow, with an average of
ten (subcopious 2). When growing in meadows proper or
on the banks of streams it often forms patches or clumps
which become conspicuous objects during September and
October from the many panicles of white-rayed flowers. In
the wet meadow the flowers are hardly noticeable on account
of the taller facies. The tall white aster is perennial by
means of rootstalks. The remaining species, Aster levis, A.
azureus, Ambrosia trifida, Carduus altissimus, Helianthus
annuus, H. tuberosus, Muhlenbergia racemosa, Acalypha
virginica, Cuscuta paradoxa, and Falcata pitcheri are ele-
ments of woodlands and thickets, or adventitious and ruderal

94 STUDIES IN THB VEGETATION OF THE STATE

species occurring only occasionally in the formation. Aster
levis and A. azurcus are woodland elements growing in prai-
ries and meadows adjacent to woody formations. These two
woodland asters occur sparsely to subcopiously in thirteen
out of twenty-seven quadrats representing important physi-
ographical variations. In other meadows, I have counted
400 individuals of each of these species in one quadrat. The
numerous light blue flower heads appear about the middle of
September and stand in marked contrast with the withering
facies. Both species are pleiocyclic, and rosette formers,
with generally several stems proceeding from the same peren-
nial root. Ambrosia trifida is a robust annual forming her-
baceous thickets in draws, ditches, and along roadsides. The
great ragweed is one of the worst roadside ruderals, since it
adapts itself to almost all conditions, though preferring
rather moist land. Its diclinic, anemophilous flowers produce
copious, powdery pollen masses which are protected by the
inverted saucer-shaped involucres. Carduus altissimus is a
tall, branched thicket and woodland species occurring rarely
in the wet meadow; it is a pleiocyclic herb and forms closed
rosettes. Helianthus annuus is prominent on account of its
extreme size by virtue of which it often becomes controlling
in the floral covering. Its distribution has been indicated
heretofore. The Jerusalem artichoke, Helianthus tuberosus,
and the horsemint, Monarda jistulosa, grow in thickets of
Corylus within the prairie, and also along the creek. Both are
pieiocyclic woodland species, perennial by rootstalks, the
former also with tubers and fleshy rootstalks. Muhlenbergia
racemosa, a frequenter of banks of streams and edges of wood-
lands, grows rather commonly in the low meadows. It is
also perennial by means of rootstalks. Acalypha virginica
is a small annual of deep woodlands found at a few stations in
the low meadows where it forms patches of rather robust in-
dividuals; it is not abundant enough, however, to be of im-
portance in the formation. Cuscuta paradoxa forms an in-
terrupted layer in the sunflower patches on the east of the

STRUCTURE OF THE FORMATION 95

wet meadow. The masses of yellowish stems are often ebun-
dant enough to be noticeable, and frequently to become con-
trolling for a short distance, in which case they cover over or
drag down many of the plants within their reach. The whit-
ish flowers are arranged in glomerate, ropy masses about the
stems to which the parasite has grafted itself. The occur-
rence of Cuscuta, like that of other parasites, is dependent
upon the distribution of its host. Falcata pitcheri is a pleio-
cyclic woodland twiner growing in the eroded beds of a few
draws near the creek. On account of the location, the short
racemes of blue flowers do not influence the aspect.

QuapraT I*—June 29, 1900

PRAIRIE FORMATION: EASTERN EXPOSURE: ESTIVAL FLORAL

ASPECT
Kuhnistera candida, 2, 1, 1, 1, 1, 1, 1, 2, 4,1, 1,1, 1, 1,1,
2,1, 4, 1, 1, 3, 2, 2, 1, 3,3, 1,1,1,1,1,1,1, 2,1, 1,1,
1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, di, 3, 1, 2, 1, i 1,
il, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 1, 1, 1, 1, 1, 1,
2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 3, 1 2, 1, 3, 1, 1,
Pe (igs PG Ft Pi Pes (ps (Pe Ls ie Pa et Wes De a Ds nd ae
2, 1, 1, 3, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1,
1, 1, 1, 1, 1, 2, 1, 1, 3, 1, 1, 1, 1, 1, 2; 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 3, 2, 1, 2, 5, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1,
1, 1,1,1,1, 2, 2,1, 2, 2, 2,1, 1,1, 1,1, 1, 2, 1, 1,1, 2,
1, 2, 3, 2, 3, 1, 1, 2, 2,3, 1, 1,1, 4, 2,1, 1, 2, 1,1, 1,1,
Sy 1, 2, 1, 1, 1, 4, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1,
2, 1, 1, 1, 1, 3, 3, 1, 1, Ay 1, 4, 3, 1, 2, 1, 1, 1, 1, 1, 1, 1,
4, 2,1, 2, 2, 2, 2,1, 2,1, 2, 1, 3, 1, 1, 2, 2, 1, 2, 1, 3, 1,
1, 1, 1, 2, 1, 2, 3, 3, 2, 1, 1, 2, 8, 1, 2, 2, 1, 1, 1, 1, 2, 1,
4, 4,4, 1,4, 4,1, 4, 1g 2, 2, 25 1p Ty Tp dy dy 85 Dy ty dy
1, 2, 1, 1, 1, 2, 2, 1, oy 1, 1, dy 1, 1, 3, 2, 1, 1, 2, 3, 1, 1,
1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, ie A 2, 1, Ain 1, i, he 1,
1,1,1,1,1,1,1,1,1, 1, 2, 2, 1, 2,1, 1,1, 1, 1, 3,1,1,

4In Quadrat I the number of stems from one root is indicated bye1ch number. To save
space this enumeration has been omitted in the remaining quadrat lists.

STUDIES IN THE VEGETATION OF THE STATE

~ eR Be RR RR RR em

resent n nnd ad

eee RG IR RS ey ORS Lae tay

area t nin adiaa

Bs Gaia NG can ee tate ae ae ee ues
MAA AANA HANAN
Bee ek ROSS ties cghe tee ged Frey es
AAA MANNA A AA
eee tee tae eee ie ee a ae
ANA AA AANA OA
KR KR KR LR ORO Nn NR KR oHR SN
aA HENAN AAA
Borah cde ve whl GEE eset ae eG nae
nate aad aad aaa
Be deta eae as a had 10 fae) aah A
ee i eS
Bin fab cide vies tothe Hien,” eee terse Tage GAR
AAA N TMNT ANAS
ee cer es eg ae AR eee egies ey
aa faei ate aa
aati oti ata ad ad
i. en
atid adtat aia
Ati eiiadtadaadaad
dee att te diad
ads aaa oae aa
Sita aaa aa
test aoe atidadad
aaa iat at fade
aneaidtan tt daad
i
Sor a Vets TR, TU eee eral ee ee ie
asian ian ieee ee ee |

.(cop. 1) 324
. (cop. 1) 249

1,

Antennaria campestris (five mats)......

Aster multifiorus....

n

n

n

n

n

n

n

n

Lespedeza capitata, 2

-(cop. 4) 90
. (cop. 4)

nn Nm,
nN nN He
nn nN KR e

nn nN NF

nan nxn an *

nan nN KN
ey

na nN HO

Cassia chamaecrista .

57

Amorpha canescens, 3,

3, 1,3, 4, 2, 2, 1, 2,

22 Bisses

.(subcop, 1) 40

Kuhnistera purpurea, 4, 1, 1, 1, 4, 1, 2, 4, 2, 1, 5, 1, 4, 1,

.(subcop.1) 28

pO se Bs ei PF

Koeleria cristata (bunches).........

.(subeop. 1) 20

15
13

.(subcop. 2) 10
. (subcop. 2)

...(subcop. 2)
...(subcop. 2)

Physalis virginiana var...........

Vernonia gigantea.....

Sisyrinchium angustifolium (bunches)...

Polygala verticillata......

7
6
5
5
4
3
2

(sparse)
(sparse)
. (Sparse)
(sparse )
(sparse)

. (subcop. 2)

Asclepias verticillata........
Anemone cylindrica, 1, 1..

Meibomia illinoensis, 1, 1, 1,1, 2.....
Viola pedatifida....

Panicum scribnerianum (bunches).....
Kuhnia eupatorioides, 8, 6, 1,1, 1........

STRUCTURE OF THE FORMATION

Aster levis, 2).3.0. 004.98 chs ese sen ea wen ne bebe
Baptisia bracteata............. 0. cece ee eee ee
Lithospermum canescens............... eee
Lactuca ludoviciana.............ceeecec eens
Psoralea argophylla................000- Mats
Facies :—
Andropogon scoparius.
A. furcatus.

QuaprRaAT IJ

(sparse)
(sparse)
(sparse)
(sparse)
(sparse)

PRAIRIE FORMATION : CREST OF RIDGE: ESTIVAL ASPECT

97

Re bb bv

Aster multiflorus.......... 0.0... cece eee eee (cop. 1)1995
Coreopsis palmata............. 0... cee eee ee (cop. 1)1416
Comandra umbellata.................00 cee (cop. 1) 402
Amorpha CanesCeDS......... 0... eee eee eee (cop. 3) 128
Kuhnistera purpurea ............. 00sec eee (cop. 4) 51
Antennaria campestris (two mats)....... (subgreg. 1) 37
Ceanothus OVatus...... 0.00. cece cee eee (subcop. 1) 29
Solidago rigida.......... 0... cee ee eee eee (subcop. 1) 28
Brauneria pallida............- 0... eee eee (subcop. 1) 21
Laciniaria scariosa ....... 6. ce cece eee (subcop. 1) 21
Panicum scribnerianum (bunches)........ (subcop. 1) 20
Viola pedatifida.......... ce eee eee eee eee (subeop. 1) 18
Koeleria cristata (bunches).............. (subcop. 2) 8
Aster oblongifolius............... 0. eee (subcop. 2) 7
Kuhnistera candida...............eee0ee (subcop. 2) 7
Rosa arkansana..... 2... cece eee eee (subcop. 2) 7
Euphorbia corollata.................08. (greg-cop. 2) 6
Physalis virginiana var...............06. (subcop. 2) 6
Carex pennsylvanica (bunches)............. (sparse) 5
Stipa spartea (bunches).............. eee uee (sparse) 4
Panicum depauperatum (bunches)........... (sparse) 3
Aste? SCTICCUB. (6649s ed eee HSE w MESES CSAS (sparse) 2
Baptisia bracteata ........... 0. eee ee eee eee (sparse) 2
Erigeron raMOsus........ cee ee eee eee eee (sparse) 2
Ruellia -ciiosanc seas ein. cl eeietiacie wats (sparse) 2

98 STUDIES IN THE VEGETATION OF THE STATE

Kuhnia eupatorioides ............ cess eeeees (sparse) 1
Lactuca ludoviciand..... ccc ece reece ecees (sparse) 1
Psoralea esculenta........ceeecsscececeeees (sparse) 1
Facies :—
Andropogon scoparius.
A. fureatus.
Bouteloua curtipendula.
QuapraT IIT
PRAIRIE FORMATION: ESTIVAL ASPECT: CREST OF RIDGE
Aster multiflorus..... 0... ccc cece eee ee eees (cop. 1)1925
Comandra umbellata........ 0... cece eee eee (cop. 1) 1460
Coreopsis palmata.......... ccc cece cee eee eee (cop. 1) 593
Kuhnistera purpurea........... cee ee ee eee (cop. 2) 150
AMOPpha CANESCENS... cece e eee eee ee eee (cop. 3) 1388
Solidago rupestrig...............--000- (greg-cop. 4) 54
Euphorbia corollata ............... 20005 (greg-cop.4) 51
Brauneria pallida........ 0... cece e eee ee (subcop. 1) 48
Oa SPRANSANA cis yaaewKeeie exe Ke Wee's (subcop. 1) 23
Viola pedatifida......... cee cee cee eens (subcop. 1) 17
Erigeron ramoOsus.......... ec eee e eee eee (subcop. 1) 16
Koeleria cristata (bunches).............. (subcop. 2) 12
Kuhnistera candida..............0c cece (subcop. 2) 12
Panicum scribnerianum (bunches)......... (subcop. 2) 10
Helianthus scaberrimus .............00055 (subcop. 2) 8
Cassia chamaecrista........ ccc cee ee eee (subcop. 2) 7
Stipa spartea (bunches}.............02 00 aes (sparse) 5
Bouteloua curtipendula (bunches)........... (sparse) 4
Sisyrinchium angustifolium................. (sparse) 3
Astragalus carolinianus........ LaaraeNon es (sparse) 2
Ceanothus Ovatus..... ccc cece cece cee eee (sparse) 2
Laciniaria SqUaTTOSA ..... 6. cee eee eee ee ees (sparse) 2
Panicum depauperatum (bunches)........... (sparse) 2
Physalis virginiana var................ee eee (sparse) 2
Solidago rigida........... Rowman whe whe eo (sparse) 2

STRUCTURE OF THE FORMATION 99

LAGIMMSPIA SCATIOSS «1405 endo esd cad eden ee ne (sparse) 1
Facies :-—

Andropogon scoparius.

A. furcatus.

QuapRAT IV,

PRAIRIE FORMATION : NORTHERN EXPOSURE NEAR BASE OF RIDGE:
LATE ESTIVAL FLORAL ASPECT

Aster multiflorus........... ccc cece cece eee (cop. 1)1325
Antennaria campestris (four mats)......... (greg. 1) 262
Kuhnistera candida ............c cece cece eees (cop. 3) 115
Meibomia illinoensigs.......... 2.0.0 e eee eeee (cop. 4) 87
Vernonia gigantea........... cee ee eee greg-cop. 4) 61
Equisetum laevigatum................-6- (subcop. 1) 44
Viola pedatifida........... 0... ee eee eee (subcop. 1) 42
Helianthus scaberrimus.................- (subcop. 1) 36
ASte? LEVIS sie wakeaa wale naa as ea cee ee Rs (subcop. 1) 25
Panicum scribnerianum.................. (subcop. 1) 25
PO@ PPALCDSIS: sisi, esaed oa eine a eis wel sliate (subcop. 1) 24
Brigeron ramosus...........eee cece scene (subcop. 1) 21
Kuhnia eupatorioides.................0.- (subcop, 1) 19
Lespedeza capitata............. ee ee ee eee (subeop. 1) 18
Scutellaria parvula............0. se ee eee (subcop. 2) 138
Panicum virgatum........... cece e ee ee eee (subcop. 2) 12
Physalis virginiana var...............065 (subeop. 2) 12
Solidago rigida........ 0. cee cee eee ee eens (subcop. 2) 12
Solidago rupestris.......... 0. cece eee ees (greg-cop. 2) 11
Muhlenbergia racemosa............eeeee- (subeop. 2) 9
AStel AZULEUSs 4 6s. caine Sei awiws wee es (subcop. 2) 8
Anemone Cylindrica........ 0. cece eee eee ees (sparse) 5
Asclepias verticillata............se eee e eee (sparse) 5
Bouteloua curtipendula (bunches)........... (sparse) 3
Euphorbia glyptosperma........-....s+eeee- (sparse) 3
Amorpha CaneSCens..... 60... eee cere cee eees (sparse) 2
Buphorbia nutans: ses <s0s.0secewer cana se re's (sparse) 2
Silphium integrifolium.............-++.++5-- (sparse) 2

100 STUDIES IN THE VEGETATION OF THE STATE

Allionia nyctaginea ovata.......... eee eee (sparse)

Corned asperifolldvacncvseuwesens+exeeeeecas (sparse)

Fragaria virginiana ..... 0... cece ee cee (sparse)

Polygala verticillata ..... 6... eee cee eee (sparse)

Vicia AMETICANA ©... eee ee tee eee (sparse)
Facies :—

Andropogon furcatus.
A. scoparius.

ele

QUADRAT V
PRAIRIE FORMATION : WESTERN EXPOSURE: LATE ESTIVAL FLORAL
ASPECT
Aster multiflorus.......... 0... cece eee eee eee (cop. 1) 2275
Meibomia illinoensis.............. 0.0. e eee (cop. 1) 672
Antennaria campestris (eight mats)........ greg. 1) 350
Kuhbnistera candida.................-.-- eee (cop. 3) 118
Equisetum laevigatum.................00 08s (cop. 4) 70
Lespedeza capitata...... 0... cece eee eee (cop. 4) 57
Silphium integrifolium...................... (cop. 4) 50
POA PLAlensis: «5.4.5 Sekekwe eulad oekewy oY (subcop. 1) 24
Panicum scribnerianum (bunches)........ (subcop. 1) 22
Vernonia gigantea.................. (sub-greg-cop. 1) 18
Asclepias verticillata................240. (subcop. 1) 16
Helianthus scaberrimus.................. (subcop. 2) 15
Viola pedatifida............... 2... cee eee (subcop. 2) 15
Bouteloua curtipendula (bunches)........ (subeop. 2) 12
Solidago rigida....... 0... 0... ce ee eee eee (subcop. 2) 9
Kuhnia eupatorioides.................00. (subcop. 2) 8
ASter l6visinacseiises is chvace qe ts Rowe e wars AWS (subcop.2) 7
Polygala verticillata.................0005 (subcop. 2) 7
Solidago rupestris..........-.. 0... e cane (greg-cop. 2) 6
ASLGE AZUPCUS 49.20 c bie sa widns waned aweeoes (sparse) 5
Linum sulcatum.... 2... 0... ccc ccc eee (sparse) 5
Beubellaria. Parva css ia oasiees dus ee sce Gea ae (sparse) 4
Heliopsis scabra..... 0... ccc cece cece eee ee (sparse) 3
Kuhnistera purpurea................ 0000 aee (sparse) 3

STRUCTURE OF THE FORMATION

Lithospermum canescens.................... (sparse )
Amorpha canescens...........0. 0000 cee ee (sparse)
Anemone cylindrica.............cceeseeeeee (sparse)
Coreopsis palmata..............00.0. cece ee (sparse)
EVI Gero: TAMUSUB. vss wk gcd aw ssceedorwae ss (sparse)
Physalis virginiana var.................000. (sparse )
Acalypha, VIPQMWGds oo .e ad es cow kas kenweens (sparse)
Astragalus carolinianus................0... (sparse)
Euphorbia glyptosperma.................005 (sparse)
Meibomia canadensis...................0005 (sparse)
Trifolium pratense...........00e cee c ee eeeee (sparse)
Facies :-—

Andropogon furcatus.
A. scoparius.
Panicum virgatum.

101

et et he bo Ob bo bo WS gg

QuaDRAT VI
PRAIRIE FORMATION : EASTERN EXPOSURE: LATE ESTIVAL FLORAL
ASPECT
Antennaria campestris (nine mats).......... (greg. 1) 322
Solidago rupestris.................-005- (greg-cop. 1) 273
Kuhnistera candida.......... 0. cece ee ee eee (cop. 2) 190
Aster multiflorus....... 0.0... cece eee ee eee (cop. 3) 105
Kuhnistera purpurea................000s (subcop.1) 49
Panicum scribnerianum (bunches)........ (subcop. 1) 25
Viola pedatifida........ ccc cece ee eee eee (subcop. 1) 21
Rosa arkansana........ eee (subcop. 1) 17
Euphorbia corollata........... 0... e eee (subcop. 2) 14
Physalis virginiana var...............44. (subcop. 2) 12
Solidago rigida........ cee ccc ee eee eee (subcop. 2) 10
Panicum depauperatum.............0000: (subeop. 2) 9
Brauneria pallida.......... 0... ee eee eee (subcop. 2) 8
Bouteloua curtipendula (bunches)........ (subeop. 2) 7
Erigeron TAMOSUS.......... eee eee eee eee (subcop. 2) 6
Kuhnia eupatorioides ..... 0.0.0. eee e eee (subcop.2) 6
Linum sulcatum............. cece eee eee (subeop. 2) 6

102 STUDIES IN THE VEGETATION OF THE STATE

Stipa spartea (buncheS)...........eeeeee (subeop.2) 6
Amorpha CaneSCeDs....... 00 eee cece eee eeee (sparse) 3
Vernonia gigantea... ... 0... cece cece ee eee (sparse) 3
AStOPr leViS) .c.e waren ewes oom Gare eS (sparse) I
Baptisia bracteata ............ Shree lg BW “ae wa (sparse) 1
Laciniaria SCari0sa..... 6... cece ec eee eee (sparse) 1
Lithospermum caneScens ............02 eens (sparse) 1
Meibomia illinoensis........... cee ee eee eee (sparse) 1
Polygala verticillata..... 0... ccc eee eens (sparse) 1
Ruellia ciliosa... 2... cc eee eee eee eet (sparse) 1
Facies :—

Andropogon furcatus.
A. scoparius.

QuapDRaT VII

PRAIRIE FORMATION: NORTHERN EXPOSURE: LATE ESTIVAL
FLORAL ASPECT

Comandra umbellata.......... 0. cece eee eee (cop. 1) 1650
Antennaria campestris (fourteen mats)...... (greg. 1)1250
Coreopsis palmata....... cece eee e eee ee eee (cop. 1)1100
Kuhnistera purpurea......... cece ee ee eee (cop. 1) 1032
Helianthus scaberrimus ............00ceeeees (cop.4) 83
Solidapo nemoralis. «.4«6.00 senses eevee anes (greg. 4) 71
Brauneria: pallida... <4.450448Geeseeeuahees ess (cop. 4) 63
Laciniaria squarrosa........... cece ccc e cece (cop.4) 55
Aste? 16VIS) oscu ase dee ee nena sd eae (cop.4) 55
Euphorbia corollata........... 00.000 cues (subcop. 1) 39
PanicWm VIP Gat s vice ven cna deeds eed saas (subcop.1) 29
Bouteloua curtipendula (bunches)........ (subcop. 1) 28
Amorpha CanesCenS...........ece eee ee ees (subcop. 1) 23
Laciniaria scariosa ......... 0... cece eee (subcop. 1) 23
Viola, pedauiGa, : sees ss was see es cea hess (subcop. 1) 21
Aster SePiCeUS.. 0.2... . cece cece e eee eee (subcop. 1) 19
ASLEP DUUPEDS I sii5 ie Wns a eure eos eed eee (subcop. 1) 18
Koeleria cristata (bunches).............. (subcop, 2) 12

JOSH, UPKONSUR Ay pk woe kes ene ear ew ewan sx (subcop. 2) 11

STRUCTURED OF THD FORMATION

Kuhnistera candida.............. 0.000 eee (subcop. 2)
Stipa spartea (bunches)................000- (sparse)
Panicum depauperatum (bunches)........... (sparse)
Tae SICA UI. hos ae nok eee de aww eam a eS (sparse)
Psoralea esculenta.......... cece cece cece eee (sparse)
Sisyrinchium angustifolium................. (sparse)
Acerates viridiflora ivesii...............000. (sparse)
CeanbThis) OVADUS A ows.a ac yerae kes ea paves es (sparse)
Facies :—

Andropogon furcatus.
A. scoparius.

QuapraT VIII

Prd bNw bh waes

PRAIRIE FORMATION : SOUTHEAST EXPOSURE: ON GREAT RIDGE:

LATE ESTIVAL ASPECT

Comandra umbellata............ cece ee wees (cop. 1) 850
Coreopsis palmata......... 0. cece eee eee eee (cop. 1) 375
Brigeron raMOsus........ cece cece cece ence (cop. 1) 281
Kuhnistera purpurea........ cece eee eee eee (cop. 2) 176
Aster multiflorus ....... 0. cece eee eee ence eee (cop.4) 74
Solidago rigida.. 2... ccc ee eee tees (subcop. 1) 46
Brauneria pallida. ...... ccc cere eee eee (subcop.1) 34
Laciniaria SQ(UuUarrosa ....... cece eee recess (subeop.1) 28
Viola pedatifida..... 0... cc cee cree ee eenee (subcop.1) 18
Euphorbia corollata............0e eee eee (greg-cop. 2) 15
ASLEEP LEVIS pieced diarrhoea eae ae ieat (subcop. 2) 14
Antennaria campeStris..........260e eee (subgreg. 2) 11
ASter SCPICCUS. 0... ee eee ee ee eee eens (subcop. 2) 11
Rosa arkansana...... cece c eee cece eee ees (subcop. 2) 11
Amorpha CaneSCeNs..... 22. eee e eee ee eee (subcop. 2) 10
Kuhnistera candida. .........ee cece ee eeee (subeop. 2) 10
Stipa spartea (bunchesS)..........++++e+5- (subcop. 2) 9
Laciniaria sCariosa ........ eee ee eee eens (subcop. 2) 7
Solidago nemoralis ......-..+eeeeeeereee (subgreg.2) 7
Koeleria cristata (bunches)........-.+--- (subcop. 2) 6

D

Physalis virginiana Var......---.eeeeeeerees (sparse)

104 STUDIES IN THE VEGETATION OF THE STATE

Helianthus scaberrimus ................000. (sparse)
Panicum depauperatum (bunches)........... (sparse)
Bouteloua curtipendula (bunches)........... (sparse)
Solidago rupestris.......... cece eee ee eee (vix-greg. )
Panicum scribnerianum (bunches)........... (sparse)
Polygala verticillata...........0e sees e cece (sparse)
Solidago rigidiuscula.............. eee e eens (sparse)
Stipa spartea (bunches)...........eeeeeeeee (sparse)
Anemone Cylindrica...... 0... cece ee ee ee eee (sparse )
Linum sulcatum.......... cece cece ec eee (sparse)
Lithospermum CanescenS....... 6. .e eee e renee (sparse)
Facies :—

Andropogon scoparius.
A. furcatus.
Carex pennsylvanica.

Quaprat IX

PRAIRIE FORMATION: HALF WAY BETWEEN FOOT AND CREST
RIDGE : SOUTHEASTERN EXPOSURE: ESTIVAL FLORAL ASPECT

OF

Kuhnistera purpurea...............eeeeeees (cop. 1) 476
Comandra umbellata....... 0.0.0. cece eee eee (cop. 1) 408
Helianthus scaberrimus ................-0085 (cop. 1) 365
Kuhnistera candida..........0...eceeeeeeees (cop. 1) 225
Solidago rupestris................ 0.000. (greg-cop. 1) 204
Aster multiflorus.......... 0... cee ee eee eee (cop. 2) 175
Antennaria campestris (three mats)......... (greg. 4) 62
Amorpha CaneSceDS......... 0. eee ee ee eee (subcop. 1) 42
Viola pedatifida............. cece ee eee eee (subcop.1) 30
Brauneria pallida........... 0.0... cece eee (subcop. 1) 28
Physalis virginiana var.......... cece e eee (subcop. 1) 17
Rosa arkansana...... 0... cece eee eee (subcop. 1) 16
Erigeron ramosus ....... 0... ee eee eee eee (subcop. 2) 14
Stipa spartea (bunches)............-...6. (subcop. 2) 12
Aster? JeViSssec ci caseee ee HenGetewrada ease (subcop. 2) 10
Euphorbia corollata...........0.004 (subgreg-cop. 2) 8

Panicum depauperatum (bunches)........ (subcop. 2)

STRUCTURE OF THH FORMATION

BOlMMaGO TS! oes ls bedi eae ew eNeaes (subcop. 2)
Solidago rigidiuscula..................... (subcop. 2)
Asclepias obtusifolia..................0.. (subcop. 2)
Stipa spartea (bunches)................. (subcop. 2)
Corecpeis palmate ss cccccanneiaanes se eos ome (sparse)
Kuhnia eupatorioides ................0.. 000. (sparse )
Laciniaria squarrosa.................00000, (sparse)
Panicum scribnerianum (bunches)........... (sparse)
Linum sulcatum........... 0... ccc ccc ee cence (sparse)
Aster oblongifolius...............c cece eeee (sparse)
Baptisia bracteata ........... cece ee cece eee (sparse)
AStePr AZUPEUS. 6... ect ee eee eeee (sparse)
Facies :—

Bouteloua curtipendula.
Andropogon scoparius.
A. furcatus.

QuapRaT X

PRAIRIE FORMATION: AT BASE OF GREAT RIDGE: EASTERN
POSURE: ESTIVAL ASPECT

Kuhnistera candida............. ccc ee eee eee (cop. 1)
Kuhnistera purpurea............ cece eee eee (cop. 1)
Antennaria campestris (seven mats)......... greg. 1)
Erigeron raMoOsus.......... cece cece cree eee (cop. 3)
Comandra umbellata........... 0... cece eee (cop. 4)
Solidago rupestris..............00ee ee: (greg-cop. 3)
Aster multiflorus..... 2... 00... cece eee eee eee (cop. 4)
Euphorbia corollata...............4. (subgreg-cop. 1)
Rosa arkansana...... cece cece eee cee aes .(subcop. 1)
Brauneria pallida. ........... 00. cece eee (subcop. 1)
Panicum scribnerianum (bunches)........ (subcop. 1)
Viola pedatifida ......... 0. cc eee eee eee (subcop. 2)
Amorpha CaneSCens..........ce eee ee eeee (subcop. 2)
Bouteloua curtipendula (bunches) ........ (subcop. 2)
Stipa spartea (bunches).................. (subcop. 2)
Aster oblongifolius ............. 00sec eee (subcop. 2)

105

el od RS]

106 STUDIES IN THE VEGETATION OF THE STATD

Physalis virginiana Var .........-. seers ewes (sparse)
Solidago rigida........ cess eee cee eee renee (sparse)
Linum sulcatum ........- cece cece ee rece eee (sparse)
Baptisia bracteata ..... 0. cece eee e cence ceee (sparse)
Cassia chamaccrista....... cece eee ee eee eee (sparse)
Kuhnia eupatorioides .......... 00. c cece eee (sparse)
Psoralea esculenta........ cece cece cence eees (sparse)
Helianthus scaberrimus...............00000- (sparse )
Meibomia illinoensis........... 0. eee eee ees (sparse)
Facies :— ‘

Andropogon scoparius.

A. furcatus.

QuapRaT XI

het mt bo bo bo bs oo Ot ot

PRAIRIE FORMATION : NEAR CREST OF GREAT RIDGE: EASTERN EX-

POSURE: LATE ESTIVAL FLORAL ASPECT

Comandra umbellata.......... eee e eee cece (cop. 1)1750
Aster multiflorus......... 0c cece ee eee eens (cop. 1) 625
Helianthus scaberrimus ......... 0... eee wees (cop. 1) 550
Kuhnistera purpurea....... cece cece eee eens (cop. 2) 163
Amorpha CANeSCENS....... cece ee cee eee eee (cop. 8) 134
Coreopsis palmata...... ccc cece eee eee eee (cop. 3) 129
Antennaria campestris (one mat)............ (greg. 4) 89
Panicum scribnerianum (bunches)......... (subecop.1) 29
Viola pedatifida........ 0... cece cece ee eee (subecop. 1) 28
Euphorbia corollata ............0000. (subgreg-cop.1) 25
Panicum depauperatum (bunches)......... (subcop. 1) 23
Solidago rupestris.............00000. (subgreg-cop. 1) 20
Rosa arkansana ........ ccc eee cece cece eee (subecop.1) 17
Bouteloua eurtipendula (bunches)........ (subcop. 2) 12
Brauneria pallida....... 0.0... cee eee eee (subcop. 2) 12
Erigeron ramosus....... 0... cece eee cece (subcop.2) 6
Solidago rigida....... cc cece cece eens (subeop. 2) 6
Stipa spartea (bunches)...............-. (subcop. 2) 6
Ceanothie Gyatus. «2.65.6 sssee ee suewee een (sparse) 5
LaCimaria SCATIO“N 2.46. ckae Wes eee vnc eas (sparse) 5

STRUCTURE OF THE FORMATION

Kuhnistera candida..............c.cceeeeee (sparse)
Chenopodium album .................00000- (sparse)
Physalis virginiana var................000-- (sparse)
Psoralea esculenta............cceccaccceeees (sparse)

Facies :-—

Andropogon scoparius.
A. furcatus.
Carex pennsylvanica.

QuapRaT XII

107

ar

PRAIRIE FORMATION: CREST OF RIDGE: LATH ESTIVAL FLORAL

ASPECT
Antennaria campestris..................04. (greg. 1)1950
Comandra umbellata............. 00 cece ee eee (cop. 1) 1900
Coreopsis: palmate... )i2e6asexasseewsarek ware (cop. 1) 900
Kuhnistera purpurea....-.......2sceenseceee (cop. 1) 425
Amorpha CaneSCens......... 00. e cece eee ees (cop. 1) 326
Euphorbia corollata................0005 (greg-cop. 4) 90
Aster MOMIAMOTUS .. 0.056 cba e des debt aioaees (cop.4) 175
Brauneria pallida............ ccc cee eee (subcop. 1) 45
Viola pedatifida................... 00200. (subcop. 1) 34
Panicum scribnerianum (bunches)......... (subcop.1) 29
Bouteloua curtipendula (bunches)........ (subcop. 1) 25
Stipa spartea (bunches)................. (subcop. 1) 17
Solidago rigida.............. 0... eee eee (subcop. 2) 15
PN) wl (2) 4 E: (subcop. 2) 12
Erigeron ramosus......... 0c eee eee eee eee (subcop. 2) 11
Panicum depauperatum (bunches)........ (subcop. 2) 9
Laciniaria scariosa......... 0. cece cece eee (subcop. 2) 6
Laciniaria squarrosa....... 6. eee e eee (subcop. 2) 6
Kuhnistera candida..... 0.0... ccc ee cee eee (sparse) 5
Linum sulcatum.......... cece eee ee eee (sparse) 3
Acerates viridiflora linearis. ............0.0005 (sparse) 2
Lithospermum Canescens....... 0... cece ee ene (sparse) 1
Physalis virginiana Var........0eseceeeeeaes (sparse) 1

108 STUDIES IN THE VEGETATION OF THE STATE

Psoralea esculenta..........seeceeeeeeeneees (sparse)
Solidago rigidiuscula ...........sseee seer eee (sparse)
Facies :-—

Andropogon scoparius.
A. furcatus.

QuapDrRAT XITI

PRAIRIE FORMATION: TOWARDS BASE OF RIDGE: SOUTHEASTERN

EXPOSURE: LATE ESTIVAL FLORAL ASPECT

Amorpha Canescens....- sees eee eee e ee ee eee (cop. 1) 425
Aster multiflorus.... 0.0.0... cece ee ee eee eens (cop. 2) 178
Kuhnistera candida. ........ 0. ccc cece ee eens (cop. 2) 169
Solidago rupestris.........- see eee eee eee (greg-cop.) 75
Meibomia illinoensis ......... 6. e eee eeeees (subcop.1) 25
Panicum scribnerianum (bunches)......... (subeop.1) 25
Euphorbia corollata ...........------ (subgreg-cop.1) 22
Viola pedatifida.......... 0. cee cee eee (subcop. 1) 21
Stipa spartea (bunches)..............006. (subcop. 2) 14
Asclepias verticillata ......... 0.0 e ee eeee (subcop. 2) 12
Kuhnistera purpurea....... 2.0... eee eens (subcop. 2) 10
Erigeron ramosus.......-.. ee cece eee eens (subcop. 2) 6
Linum sulcatum ............. eee ee eee ee (subcop. 2) 6
Brauneria pallida........ cc cece eee ee eee ees (sparse) 5
Acerates viridiflora ivesii..... 0.0.0.0... 00000 (sparse) 4
Physalis virginiana var.............0.-ee cere (sparse) 4
Solidago rigidiuscula...................006. (sparse) 4
Fragaria virginiana ..............0 cece eens (sparse) 3
Hieracium longipilum ....................6- (sparse) 3
Laciniaria scariosa....... 6. cece eee eee (sparse) 3
Baptisia bracteata....... 0... cee eee eee (sparse) 2
Apocynum cannabinum................000 ee (sparse) 1
Carduus altissimus................c eee wees (sparse) 1
Kuhnia eupatorioides ..................2-- (sparse) 1
Silphium laciniatum.....6¢0s002s008skeeee ss (sparse) 1

STRUCTURE OF THB FORMATION 109

Facies :— .
Andropogon scoparius.
A. furcatus.

Bouteloua curtipendula.

QUADRAT XIV

PRAIRIE FORMATION: NORTHEAST EXPOSURE: HALF WAY UP
RIDGE: LATE ESTIVAL FLORAL ASPECT

Comandra umbellata............0 ccc eee ees (cop. 1)1275
Kuhnistera purpurea........... cece eee e eens (cop. 1) 575
Aster multiflorus..... 00... cc cece eee eee eee (cop. 1) 275
Coreopsis palmata......... 0... cece cece ee eeee (cop. 3) 125
AMorpha CamesCens,.. cys 2c asecenees tes ears (cop. 4) 90
Euphorbia corollata................000. (greg-cop. 4) 86
Solidago rupestris......... 0.0.0 .e ee eaee (greg-cop. 4) 51
Amorpha CanesCens ....... 0... ee eee eee (subcop.1) 44
Brauneria pallida. ... 0... .. cece ee eee eee (subcop.1) 29
Aster 1@vi8 «psa: sessessues sh Ga Shih ah Sid. hike alot (subcop.1) 20
Equisetum laevigatum...............0000- (subcop.1) 19
Rosa arkansana........... cee eee ee ee eee (subcop. 1) 16
Cassia chamaecrista.......... ccs cece ee eee (subcop. 2) 15
Viola pedatifida.......... 00... cece ee eee (subcop. 2) 12
Antennaria campestris (bunches)........ (subgreg. 2) 10
Bouteloua curtipendula (bunches)......... (subcop.2) 10
Erigeron raMoOsus.... 2.2... cece ee eee ee eee (subcop. 2) 10
Linum sulcatum..............cc cece ee eee (subcop. 2) 9
Kuhnia eupatorioides ............. cece ease (sparse) 5
Laciniaria sCariosa..... 6... cece ee eee eee (sparse) 5
Koeleria cristata (bunches)..............455 (sparse) 4
Nabalus aspe? ..cccscesaiesoceedaie ecg ees (sparse) 4
Sisyrinchium angustifolium (bunches)....... (sparse) 3
Solidago Vigida..ccsccseenciscneas sewed aees (sparse) 3
Carduus altissimus........... 0. 0c eee eee eee (sparse) 2
Lithospermum CaneSCemS.......... eee eeee (sparse) 2
Solidago rigidiuscula.............e cee eeeees (sparse) 2
Vernonia gigantea.............. eee eee sees (sparse) 2
Ambrosia trifida..... 6... ccc eee eee eee (sparse) 1

110 STUDIES IN THE YEGETATION OF THE STATE

Lactuca ludoviciana ......... ccc eee e cece eees (sparse) 1
Polygala verticillata........ cc cee eee cee e ees (sparse) 1
Facies :—

Andropogon scoparius.
A. furcatus.
Panicum scribnerianum.

QUADRAT XV

PRAIRIE FORMATION: NORTHEAST EXPOSURE: HALF WAY UP
RIDGE: LATE ESTIVAL ASPECT

Antennaria campestris (estimated).......... (greg. 1) 2050
Comandra umbellata............eeees Soca (cop. 1) 375
Cassia chamaecrista........ cece cee ee eee (cop. 3) 140
Kuhbnistera candida ........... cece ee eee eee (cop. 3) 115
Aster multiflorus ..... 0.0... cece eee eee eee (cop. 3) 105
Amorpha CaneScens ...... 02. see eee ee eee eee (cop.4) 92
Coreopsis palmata ....... ec ccc cece eee nee (cop.4) 86
Kuhnistera purpurea .............06- Stee caty ass (cop.4) 75
Euphorbia corollata ................- (subgreg-cop.1) 39
Brauneria pallida ........... cece ee cee ees (subcop.1) 27
Rosa arkansana ........ cece eee eee eee .(subcop.1) 26
Solidago rupestris .................. (subgreg-cop.1) 24
Helianthus scaberrimuy ...............005 (subcop.1) 21
Poldsee Rielle... ess genet wees pea gees (subcop.1) 17
ViUla PSGAifids: c50c ere a iiaesse eae e ee .(subcop.1) 17
HErigeron ramOsus ......... cee eee eee eee (sparse) 5
Gentiana puberula ......... 0. cc cece cee eeeee (sparse) 4
Acerates viridiflora ivesii...........0 0 cee eens (sparse) 3
Panicum depauperatum (bunches)........... (sparse) 3
Polygala verticillata ............cc cee eeeees (sparse) 3
Lactuca ludoviciana..............2.005 .... (sparse) 2
Physalis virginiana var............... nea aies (sparse) 2
Aster 1eViS sa cigs eam ues eeu eeeen eae odes (sparse) 1
Baptisia bracteata ....... 0... cece cece cece (sparse) 1
Kuhnia eupatorioides ..............85 eee (sparse) 1

STRUCTURE OF THE FORMATION

TACINIAPIA SCAPIOST 6.0.06 coe sae bn os See es (sparse)
Lin SUCATORY casseas cinevasteee valves aries (sparse )
Facies :—

Andropogon scoparius.
A. furcatus.
Panicum scribnerianum.

QuUADRAT XVI

PRAIRIE FORMATION : WESTERN EXPOSURE: HALF WAY UP BIDGE:

LATE ESTIVAL ASPECT

Comandra umbellata ............ cece eee eee (cop. 1)
Amorpha C&Nescens ......... cece eee (cop. 1)
Aster multiflorus 1.0... 0.0... ce cece eens (cop. 1)
Coreopsis palmata ....... 0... 0 cece eee eee (cop. 1)
Kuhnistera purpurea ............. eee eee eee (cop. 3)
‘Euphorbia corollata ........... 0... eee eee eee (cop. 4)
Antennaria campestris (1 mat)............. (greg. 4)
Brauneria pallida ............. cess eeees (subcop. 1)
Kuhnistera candida ..............0.ee005 (subcop. 1)
Solidago rigidiuscula .................06. (subcop. 1)
Koeleria cristata (bunches) .............. (subcop. 2)
Cassia chamaecrista .........0.- 2 cece eee (subcop. 2)
Panicum scribnerianum (bunches) ........ (subcop. 2)
Linum sulcatum ......... 0... cece eee ees (subcop. 2)
Laciniaria scariosa ............ee eee .--(subcop. 2)
Panicum depauperatum (bunches). ee ee (sparse)
Bouteloua curtipendula (bunches)........... (sparse)
Erigeron rAMOSUS «0... eee cece teens (sparse)
Viola pedatifida....... 0... cc cece eee eee eee (sparse)
Rosa arkansana ......-c.c cere cv ecenecesens (sparse)
Solidago rupestris .........0. cece cece ee eeee (sparse)
Acerates viridiflora ivesii.........e eee e ee ees (sparse)
Kuhnia eupatorioides..........0e cece eee eee _. (sparse)

Physalis virginiana Var .......-.seeeeeeeeeee (sparse)

550
325
275
206
116
87
51
33
32

10

el a OO So eS )

112 STUDIES IN THE VEGETATION OF THE STATE

Facies :—
Andropogon scoparius.
A. furcatus.

QUADRAT XVII

PRAIRIE FORMATION : EXPOSURE WESTERN, ABRUPT SLOPE: LATE
ESTIVAL FLORAL ASPECT

Antennaria campestris (14 mats)............ (greg. 1) 1750
Comandra umbellata ...........-.essee eens (cop. 1) 1450
Aster niultiflornd g4ci.c..¢0002seaneccannanes (cop.1) 575
AmMorpha CANESCENS .. 6... eee eee eee eee (cop. 3) 142
Kuhnistera candida............0.ce eevee (subcop.1) 20
Kuhnistera purpurea ...........ec cece eee (subcop.1) 19
Bouteloua curtipendula (bunches)......... (subcop.2) 12
Stipa spartea (bunches)..............+40. (subcop.2) 12
Erigeron ramosus .......0. ss cece ee ee eae (subeop. 2) 10
Panicum scribnerianum (bunches) ........ (subcop.2) 9
Rosa arkansana ....... 00. c cece eee ee eens (subcop.2) 6
Laciniaria scariosa.......... cee eee eee eee (sparse) 4
Panicum depauperatum (bunches)........... (sparse) 4
Koeleria cristata (bunches)................. (sparse) 3
Ambrosia trifida ......... cece eee ee ee cee eee (sparse) 2
Viola pedatifida ...... 0... cc cece cee eee aes (sparse) 2
Acerates viridiflora ivesii.............--.20.- (sparse) 1
Agrostis hiemalis .......... 0c. cece cee cece (sparse) 1
Astragalus crassicarpus .........- cece eee (sparse) 1
Euphorbia corollata ..... 0... cece eee eee (sparse) 1
Genhana puberwla ics. ose seus es wees ee aces (sparse) 1
Linum sulcatum ........... cece eee eee (sparse) 1
Psoralea argophylla ....... 0... cee ee eee ee ee (sparse) 1
Solidago rigidiuscula ........... ccc eee ee eee (sparse) 1
Vernonia Cisamted: vx x oe vaie eRe ee ae aanewee (sparse) 1
Facies :—

Andropogon scoparius.
A. furcatus.

8

STRUCTURE OF THE FORMATION 113
QUADRAT XVIII

: \
PRAIRIE FORMATION : NORTHWEST EXPOSURE: MIDWAY BETWHEN
CREST AND FOOT OF RIDGE: LATE ESTIVAL ASPECT

Comandra umbellata.............. 0.000 ee «. (cop. 1) 1900
Antennaria campestris..............0..00065 (cop. 1) 929
Amorpha Canescems.......... 000. ee ene (cop. 1) 500
Coreopsis palmata........... 00.00 eee eee eee (cop. 2) 190
Euphorbia corollata .................00- (greg-cop.3) 110
Brauneria pallida....... 0... 0... cece eens (subcop.1) 49
Kuhnistera purpurea...............0500. (subcop. 1) 34
AStEM levis: che by sr weysnses os eee Hoe (subcop. 1) 28
Aster multiflorus..................00 00 (subcop. 1) 28
Panicum scribnerianum (bunches)......... (subeop. 1) 25
Viola pedatifida.............. 0.0.0 e eee (subcop. 1) 25
Laciniaria squarrosa......... cece ee eee (subcop. 2) 12
Laciniaria scariosa............... eee eee ee (subcop. 2) 11
Rosa arkansana.......... 0 cece ee cee eee (subcop. 2) 11
Solidago nemoralis.................505. (sub-greg. 2) 8
Erigeron ramosus..... 6... 0s eee eee eee ee (subcop.2) 6
Helianthus scaberrimus ...........-.---+--- (sparse) 5
Panicum depauperatum (bunches)........... (sparse) 5
Kuhnistera candida........... 00 cee eee eee (sparse) 4
Linum suleatum......... 0.06 cece eee ees (sparse) 4
Bouteloua curtipendula (bunches)........... (sparse) 2
Kuhnia eupatorioides ...........6.eeee eee (sparse) 1
Panicum pubescens. ........ 0s secre creer eee (sparse) 1
Vernonia gigantea. .......eeeeee escent eee (sparse) 1
Facies :—

Andropogon scoparius.
A. furcatus.

114 STUDIES IN THE VEGETATION OF THE STATE

QUADRAT XIX

PRAIRIE FORMATION: TOWARD FOOT OF RIDGE: NORTHWEST EX-

POSURE: LATE ESTIVAL FLORAL ASPECT

Antennaria campestris (twelve mats)........ (greg. 1)
Comandra umbellata....... 0... cee eee eee (cop. 1)
Kuhnistera candida.......... 00. cece eee eee (cop. 1)
Coreopsis palmata.... 6... cece cee eee eee eee (cop. 3)
Euphorbia corollata .................00. greg-cop. 3)
Carex pennsylvanica (bunches).............. (cop. 4)
Amorpha CaneSCeDS....... 6. cece eee eee eee (cop. 4)
Brauneria pallida............ 0. eee eee eee (subcop. 1)
Bouteloua curtipendula (bunches)........ (subcop. 2)
Hrigeron ramosus ....... ee eee ee eee eee (subcop. 2)
Panicum scribnerianum (bunches)......... (subcop. 2)
Rosa arkansana@......... cc cece eee eee (subcop. 2)
Kuhnistera purpurea.......... 00. c eee ane (subcop. 2)
Solidago rigidiuscula.................... (subcop. 2)
Viola pedatifida....... 0... 0. . cece cee ees (subcop. 2)
Aster AZULCUS. 2.6... eee eee (subcop. 2)
Laciniaria scariosa ......... 0... c cece eee (subcop. 2)
Panicum depauperatum (bunches) ........... (sparse)
Linum sulcatum........... 00.00. c eee eee es (sparse)
Lithospermum canescens...............00008 (Sparse)
STEER EVIE Cavin ul sand eeehauern peared ees (sparse)
Kuhnia eupatorioides ...................... (sparse)
MOlMagG PMMA so iueaus ase hah aadonaawepaek (sparse)
Acerates viridiflora ivesii.................0.. (sparse)
Sisyrinchium angustifolium (bunches)........ (sparse)
Solidago rupestris.............cccceeeeeeees (sparse)
Facies :—
Andropogon scoparius,
A. furcatus.

Koeleria cristata,

855
450
356
13T
135
100

88

10

BR BE DDN WP PEP OTRM AN Aw ©

STRUCTURE OF THE FORMATION

QuapDRAT XX

PRAIRIE FORMATION : NORTHERN EXPOSURE: ON CREST OF RIDGE:

LATE ESTIVAL FLORAL ASPECT

Coreopsis palmata........... 0.0. c cee eee eee (cop. 1)1100
Comandea palidass .¢i0icawekiiduseddioeaaes (cop. 1) 1050
Antennaria campestris (four mats).......... (greg. 1) 237
Brainerd Palitdevedweavweeoves secre wos (cop. 4) 60
Aster multiflorus........... 0.0.00. c ee ee eee (cop. 4) 56
Buphorbia corollata...............00000% (greg-cop. 4) 50
Laciniaria scariosa ......... 00.00 eee e eee (subcop. 1) 33
Erigeron ramosus...........00ceee cence (subeop. 1) 24
Kuhnistera purpurea................005- (subcop. 1) 18
Silphium laciniatum..................... (subecop. 2) 13
Solidago rigida.......... 0... cc ce eee eee (subcop. 2) 13
Kuhnistera candida................-...-- (subcop. 2) 9
Bouteloua curtipendula (bunches)........ (subcop. 2) 8
Rosa arkansana..... ccc cece eee eee eee ees (sparse) 5
Stipa spartea (bunches)................-2.5 (sparse) 5
Viola pedatiiida,..:. asa cockewswnardiaies ees (sparse) 5
Panicum depauperatum (bunches)........... (sparse) 4
Amorpha CamescensS....... 02. c eee eee eee ees (sparse) 3
Ceanothus OvatusS....... 0.00. cece eee ee eens (sparse) 3
Acerates viridiflora ivesii................... (sparse) 1
Amaranthus graecizans..............0.0008- (sparse) 1
Eatonia obtusata (bunches)................. (sparse) 1
Dimi SU Catt iosg esccce oeccen ie aig.) ee eee ekigce ates (sparse) 1
Lithospermum canescens. ..........000.e eee (sparse) 1
Facies :—

Andropogon scoparius.
A. furcatus.
Koeleria cristata.

116 STUDIES IN THE VEGETATION OF THE STATE
QUADRAT XXI

PRAIRIE FORMATION : NORTHWEST EXPOSURE: MIDWAY BETWEEN
FOOT AND CREST OF RIDGE: LATE ESTIVAL FLORAL ASPECT

‘Antennaria campestris (seven mats)........ (greg. 2) 185.
Coreopsis palmata.......... Liptarsdevessawelenp. 2) we
Comandra umbellata...................024-. (cop. 2) 150
FEMS eny PUL PUTNEE on ov one arin ace mew weaiee (cop. 3) 119
Brauneria pallida.............. 0.0.00. (cop. 3) 117
Euphorbia corollata.................... (greg-cop. 3) 107
Linum sulcatum.... 1.0.0... cece eee (cop. 4) 63
Erigeron ramosus......... 00.0 c ee eee ee eee (subcop. 1) 32
Amorpha canescens. .... 0.6... 0c eee ee eee (subcop. 1) 26
Koeleria cristata (bunches).............. (subcop. 1) 16
Solidago rigida.......... 0.00. e cee eens (subcop. 2) 13
Laciniaria squarrosa ..... 6... 6c ee ees (subcop. 2) 12
Aster multiflorus...................00085 (subeop. 2) 10
Stipa spartea (bunches).................. (subcop.2) 8
Kuhnistera candida...................06. (subcop. 2) 7
Panicum depauperatum (bunches)........... (sparse) 5
Wile, Peds ncaa saan ausmna counties (sparse) 5
Sisyrinchium angustifolium (bunches)....... (sparse) 4
Acerates viridiflora linearis ................. (sparse) 3
Solidago nemoralis....................00. (vix-greg.) 3
Aster AZUTCUs' scccciiesanene en eae eee sans (sparse) 1
Lithospermum canescens..............-..26- (sparse) 1
Physalis virginiana var.................000e (sparse) 1
Polygala verticillata............. cece eee eee (sparse) 1
Facies :-—

Andropogon scoparius.
A. furcatus.
Bouteloua curtipendula,

STRUCTURE OF THE FORMATION

QUADRAT XXII

117

PRAIRIE FORMATION : NORTHWEST EXPOSURE: AT FOOT OF RIDGB:

‘LATE ESTIVAL FLORAL ASPECT

Antennaria campestris (twenty mats)........ (greg. 1) 1300
Comandra umbellata................ce cee eee (cop. 1) 850
ASTEY MMA PUR < 65464 o 345-4 Se dalchmaweneaars (cop. 1) 625
Amorpha canescens........... 0.00 cece cece ee (cop. 2) 180
Kuhnistera candida..................000% (subcop.1) 45
Linum sulcatum................ cee ee eeee (subcop. 1) 37
PEITIPErON TAMOSUS sss ce ae pee eeegee es (subcop.1) 23
Rosa arkansana............cccccceeeeeee (subcop. 1) 18
Kuhnistera purpurea..................00. (subcop.1) 16
Solidago rupestris................000085 (greg-cop.2) 138
Viola pedatifida........... 00... ce cee ee (subcop. 2) 12
Polygala verticillata..................0.0. (subcop. 2) 10
Agrostis hiemalis.................0--0005 (subcop. 2) 7
Coreopsis palmata................0 ee eae (subcop. 2) 7
Panicum scribnerianum (bunches)......... (subecop.2) 7
Psoralea argophylla........... 0.000 e eae (subcop.2) 7
Euphorbia corollata................600. (greg-cop. 2) 6
Helianthus scaberrimus .........-...-.0000- (sparse) 5
Brauneria pallida......... 0... ccc ee eens (sparse) 4
Hieracium longipilum...................... (sparse) 4
Panicum pubescens (buncheS)............... (sparse) 4
Anemone cylindrica............... 0c eee eee (sparse) 3
Kuhnia eupatorioides ...................00. (sparse) 3
Vernonia fasciculata. ...... 0... cece eee e eee (sparse) 3
EKatonia obtusata (bunches)................. (sparse) 2
Lespedeza capitata........... 02. cece ee eee (sparse) 2
AStér AZULeCUS: oa ser wg Gets saeiaeee Geek eas (sparse) 1
Koeleria cristata (bunch)................... (sparse) 1
Laciniaria scariosa .... 6... cece cee tenes (sparse) 1

1

Solidago rigida ......... 0. cee cee eee eee ee (sparse)

118 STUDIES IN THE VEGETATION OF THE STATE

Facies :—
Andropogon scoparius.
A. furcatus.

QuapRaT XXIII

MEADOW FORMATION: NORTHERN EXPOSURE: LATE ESTIVAL

FLORAL ASPECT

Chaetochloa glauca. ....... 6. cee cee eee eee (cop. 3) 125
Teucrium occidentale. ............-20-56- (subcop. 1) 37
Convolvulus sepium ...........ee ee eee eee (subcop. 1) 36
Vernonia gigantea....... 0... 2. cee cece eee (subcop. 1) 33
Amorpha Canescens........ 6.2 eee cece eee (subcop. 1) 21
Acalypha virginica. ........6e ee eee eee eee (subcop. 2) 138
Panicum scribnerianum (bunches)......... (subcop. 2) 18
Euphorbia glyptosperma ..............06. (subcop.2) 11
Thalictrum purpurascens...............-. (subeop. 2) 8
Asclepias verticillata................0000- (subcop.2) 6
Kuhnia eupatorioides ................000- (subcop. 2) 6
Oxalis stricta... o.6244 .¢200.saw es eee eens (subcop. 2) 6
Kuhnistera candida.............. 0.0.0 ee eee (sparse) 4
Viola obliqua...... 0... cece ee eens (sparse) 4
Lespedeza capitata.......... cece eee ee eee (sparse) 3
Polygonum emersum......... 2. ccc ee eee ees (sparse) 3
Rosa arkansana....... 2... ee eee eee cee eee (sparse) 3
Aster AZUFCUS. 2... ccc eee es (sparse) 2
Heliopsis scabra ....... 00... eee eee ee eee (sparse) 2
AsclepiaS Syriaca... 2... 2. eee eee eee eee (sparse) 1
Aster multiflorus. ...... 2.2... ccc eee eee eee (sparse) 1
Euphorbia corollata............0 ee cece ee (vix-greg.) 1
Laciniaria scariosa ............ 0.02 cee eens (sparse) 1
Physalis virginiana var............. 0 cece eee (sparse) 1
Solanum carolinense.............. 00. e eee eee (sparse) Il
Solute TiPidh «cso sreedeckeeeeduerourwuies (sparse) 1
Facies :—

Andropogon furcatus.
A. scoparius.

STRUCTURB OF THE FORMATION

Panicum virgatum.
Chrysopogon avenaceus.
Elymus canadensis.

119

144
15
54
48
31
13
12
10

f—)

QUADRAT XXIV
MEADOW FORMATION: OPEN EXPOSURE: LATE ESTIVAL ASPECT
Asclepias verticillata........ 0. eee c eee (cop. 2)
Antennaria campestris (four mats).......... (greg. 4)
Polygonum emersum......... 0. cee eee eee eee (cop. 4)
Kuhnistera candida.............. 0. eee eee (subcop. 1)
Convolvulus sepium .................006. (subcop. 1)
Kuhnia eupatorioides .................04. (subcop. 2)
Anemone canadensis.............---- (subgreg-cop. 2)
Panicum scribnerianum (bunches)......... (subcop. 2)
Vernonia gigantea............--..0-- (subgreg-cop. 2)
Aster paniculatus.... 0.0.0.0... ccc eee eee (subcop. 2)
Kuhnistera purpurea............. 02 ee eee (subcop. 2)
Aster multiflorus....... 0... 0. ce cece ee eee (subcop. 2)
Amorpha CaneSCensS....... 0.06. eee eee (subcop. 2)
OXAlIS RUN Cldi Sia esos cies eiaiean ene eeoreeis (subcop. 2)
Polygala verticillata .......... 0.02.0 e eee (subcop. 2)
ASter aZzUreuS.. 2. ssse0ecoaaie Sasa ww oe Rass (sparse)
Euphorbia glyptosperma..............+-+-5 (sparse )
Lactuca pulchella ..... 0... ccc eee eee (sparse)
Physalis virginiana var.... 2.0.0... eee eee (sparse)
Solidago rigida....... 0... cece ee ee eee (sparse)
Lespedeza capitata........ cece cece ees (sparse)
Aster léVi8 202 cies eaaw se ene oe eee oes Reels Boe (sparse)
Fragaria virginiana .......... cece eee eee (sparse)
Heliopsig scabra...... 0... cee cee eee eee eee (sparse)
Lactuca ludoviciana. ....... 6. cece eee eens (sparse)
Apocynum cannabinum.............. eee eee (sparse)
Meibomia illimoensis............ 0.00 cece cues (sparse)
Monarda fistulosa....... 00.0 eee cece eects (sparse)

Silphium perfoliatum...........0.. cee ee eeee (sparse)

ee ee DDN HY WEP ERTAMAAARMANIMWS

120 STUDIES IN THE VEGHTATION OF THE STATE

Viola pedatifida.... 0... 0. sec e eee ec ence eae (Sparse)

Facies :—
Andropogon furcatus.
Andropogon scoparius.
Panicum virgatum.
Chrysopogon avenaceus.
Elymus canadensis.

1

79
64
54
29
29

QUADRAT XXV
MEADOW FORMATION: OPEN EXPOSURE: LATE ESTIVAL ASPECT
Asclepias verticillata.... 0.0.0... cee eee eee (cop. 4)
Anemone canademsiS....... 00. c eee ences (greg-cop. 4)
Antennaria campestris (three mats)......... (greg. 4)
Aster multiflorus......... 0. cece eee ee eee (subcop. 1)
Panicum scribnerianum (bunches)......... (subcop. 1)
Salix fluviatilis..... 0.0.0... ce cece ee eee (subcop. 1)
Kuhnistera candida................00000. (subcop. 1)
Meibomia illinoensis...................4. (subcop. 1)
Oxalis Strictars ss suc aio ceeds ede wale Bie Bales (subcop. 1)
Euphorbia glyptosperma ................. (subcop. 1)
Polygonum. emersum........... 2. ce eee (subcop. 1)
ASter AZULGUS o.oo ce aS ea aaa eda ee TO (subcop. 2)
Fragaria virginiana..............0e eee eee (subcop. 2)
Helianthus scaberrimus ..................(subcop. 2)
Silphium integrifolium................... (subcop. 2)
Amorpha canescens............ ccc eee eee (subcop. 2)
VORnONia, BIGANTCRs wees cu keane ade wa cess (greg-cop. 2)
Aster LOVIS! .s36na.o bet aaisieewde nse seys ....(subcop. 2)
Laciniaria pycnostachya...............64. (subcop. 2)
Apocynum cannabinum................... (subcop. 2)
Kuhnia eupatorioides ................000. (subcop. 2)
Aster paniculatus. ........0.... 000 cece e ees (subcop. 2)
Polygala, vertivillate. sux svsaneascaee eves os (subcop. 2)
Lespedeza capitata..... 0... cece eee eee (subcop. 2)

Baptisia, leucantha.... 0. ciewa rst ee ene eae (sparse)

STRUCTURE OF THE FORMATION

Physalis virginiana var..................... (sparse)
Kuhnistera purpurea....................00. (sparse )
Silphium perfoliatum.....................0. (sparse)
FICHOpRis BCADTE cd cuss deans cena wa vis eonaee (sparse)
DOS: CIADPE. ok sous oa eaawenaoaaes sewn saaee -. (sparse)
HORA AER NRNTA 52 cndenconsouaGkeeabes aouas (sparse)
BOMMAVOVTIDIN 24-3tu ax ae eer eee va ew ouees (sparse)
Facies :—

Andropogon furcatus.
A. scoparius.
Panicum virgatum.
Elymus canadensis.

QuADRAT XXVI

121

Meow Ss wwe

MEADOW FORMATION: OPEN EXPOSURE: LATE ESTIVAL FLORAL

ASPECT
Antennaria campestris (fourteen mats)...... (greg. 1) 2500
Comandra umbellata.....................0.. (cop. 1) 320
Equisetum laevigatum................. 0.0005 (cop. 1) 260
Kuhnistera candida....................0. (subcop. 1) 45
Panicum scribnerianum (bunches) er ea (subcop. 1) 35
Aster multifiorus............. 00.000. e eee (subcop. 1) 20
Kuhnistera purpurea......... 0.60.00 eee (subcop. 1) 20
Helianthus scaberrimus ...........-...55- (subcop.1) 19
Bouteloua curtipendula (bunches)........ (subecop. 2) 14
Euphorbia corollata ................. (subgreg-cop. 2) 14
Amorpha canescens..............000 20 eee (subcop. 2) 8
Linum sulcatum ....... 0... cece ee eee (sparse) 5
Viole peqgidacsoca esky seewussewarieouys (sparse) 5
Coreopsis palmata......... 0... cc cee eee eee (sparse) 4
ASlet AVUTCUG 56th hea eo alte Genes eee pee (sparse) 3
Laciniaria pycnostachya .................04. (sparse) 3
Vernonia gigantea........... 0 cece eee eee eee (sparse) 3
Kuhnia eupatorioides ..................000. (sparse) 2

Anemone CyliNdriCs. :ceceysuenisvidansre wees (sparse)

—_

122 STUDIES IN THE VEGETATION OF THE STATE

ed dad

Meitomia Ulinoensis i... ca.ccaa sacra eases (sparse)

Rosa arkansana..... 02.0. cece cence cece eeeee (sparse)

Silphium laciniatum...................0000. (sparse)

Solidago rigidiuscula..................00005 (sparse)
Facies :—

Andropogon scoparius.
Andropogon furcatus.
Chrysopogon avenaceus.

QUADRAT XXVII

Sl ol |

MEADOW FORMATION: OPEN EXPOSURE: LATE ESTIVAL ASPECT

Antennaria campestris (twelve mats)........ (greg. 1) 475
Aster multiflorus........ 0... cece cece eee eee (cop. 1) 435
Helianthus scaberrimus .............. 0000005 (cop.4) 70
Euphorbia corollata ..............045 (subgreg-cop.1) 49
Kuhnistera candida..................000. (subcop. 1) 42
Asclepias verticillata ......... 0.0.0.0 eee (subcop. 1) 28
Viola pedatifida ..... 0.2.0... ccc eee eee (subcop. 2) 12
Panicum scribnerianum (hanehes) sch gatas sti (subcop. 2) 11
Erigeron ramosus ........ 6.0.00 cece eee (subcop.2) 8
Physalis virginiana, var... cs iceyaccae ences (subcop. 2) 8
Amorpha Canescens............0.ce cece ee (subcop. 2) 6
Convolvulus sepium.............0...000 ee (subcop. 2) 6
Kuhnia eupatorioides .................... (subcop. 2) 6
Polyeala yerticillaten vs o00s64005so01G44k ena. (sparse) 5
PONdAeO TSA cee ea sdaw ek dee ee wee eee eae (sparse) 5
Anemone cylindrica... .24053seues enw ue aes (sparse) 4
Laciniaria pycnostachya .................0.. (sparse) 4
ACP CVS Scanner vedas wayne gasuae eee ease (sparse) 38
ANSLEY WANES. eeesipos ks cede dteencidygiaes (sparse) 2
Kuhnistera purpurea........ pe esa an Sate (sparse) 2
Lespedeza. capitata.ssccxsanan se evs vie sdacae (sparse) 2
Lactuca ludoviciana.................0000 eee (sparse) 1
Meibomia illinoensis....................0005 (sparse) 1
Silphium perfoliatum....................... (sparse) 1

STRUCTURE OF THE FORMATION 123

Vernonia gigantea...... 0... . eee eee eee eee (sparse) 1
PAP AMVC R sacs tin aaa bd ea aed mle ans ele ee (sparse) 1
Facies :—

Andropogon scoparius.
A. furcatus.
Panicum virgatum.

QuapDRAT XXVIII

WET MEADOW FORMATION: LATE ESTIVAL FLORAL ASPECT

Rumex CVISPUS! accede ates wade a bea (sparse) 5
Phalaris arundinacea (bunches)............. (sparse) 4
Aster paniculatus.......... cece eee ee eee (sparse) 3
Cicuta maculata........ 0... eee eee eee eee (sparse) 2

Facies :—
Poa pratensis.
Calamagrostis canadensis.
Carex vulpinoidea.
Eleocharis palustris.
Carex cephaloidea.

QUADRAT X XIX

WET MEADOW FORMATION: LATE ESTIVAL FLORAL ASPECT
Physalis longifolia............-. 0c eee eee (subcop. 1) 34
Lactuca canadensis............ 00sec eee (subcop. 2) 10
Aster paniculatus.............. ee cece eee (subcop. 2) 6
Plantago rugelilit........ccsweseeys eae swaes (subcop. 2) 6
Phleum pratense .....-....0 cece cee eceenees (sparse) 5
Heliopsis scabra...... 6... cece eee eee eens (sparse) 4
Asclepias SyTiaCa.. 6... cece eee (sparse) 1
Carduus altissimus.........ccescccae reece (sparse) 1

Facies :-—

Carex stricta.

C. vulpinoidea.

C. cephaloidea.

Poa pratensis. _
Eleocharis palustris.

124 STUDIES IN THE VEGETATION OF THE STATE
QuapRAaT XXX

WET MEADOW FORMATION: LATE ESTIVAL ASPECT

Oxalis stricta... ccc cee cece een eee ees (cop. 3) 116
Asclepias verticillata..........00cecceneeeeee (cop. 4) 57
Lactuca ludoviciana............. 00. cece ee (subcop.1) 27
Teucrium occidentale.................000. (subcop. 1) 19
Aster paniculatus ee eR ae nr aera rene (subcop.1) 16
Cicuta maculata ........ cee eee ee eee (subcop. 2) 15
Heliopsis scabra....... ec cece cece ences (subcop. 2) 14
Onagra bienniS......... 00... e ce ee eee (subeop, 2) 11
Potentilla monspeliensis................5. (subcop. 2) 8
Aster multiflorus..... 0... cee cece eee ee (sparse) 5
Vernonia fasciculata............ ce cece eee es (sparse) 2
Carduus altissimus.........0. 00. cece eee eee (sparse) 1
Aya. SANUNIONG) oc gee can eu Qe Re ewe reeks (sparse) “1
Plantago rugellii........ eee cee eee eee (sparse) 1
Facies :—

Spartina cynosuroides.
Poa pratensis.
Eleocharis palustris,

QuapDRaT XXXII

WET MEADOW FORMATION: LATE ESTIVYAL FLORAL ASPECT

Vernonia fasciculata................0000. (subcop. 2)
Apocynum cannabinum................00005 (sparse)
Facies :-—

Carex vulpinoidea.
Carex cephaloidea.
Carex stricta.
Spartina cynosuroides.
Eleocharis palustris,

STRUCTURE OF THE FORMATION 125

QUADRAT XXXII

WET MEADOW FORMATION: LATE ESTIVAL FLORAL ASPECT ~*

Phalaris arundinacea .................005 (subcop. 2)
ABLEY PANICUIBING ss nnswesesaxsuacceae vce’ (subcop. 2)
Lythrum alatum............ 0.00000 ceca (subcop. 2)
Cicuta maculata...... 2... eee cee eee (subcop. 2)
Vernonia fasciculata............. 0c eee (subcop. 2)
Lycopus americanus.............000cee eee (subcop. 2)
Polygonum pennsylvanicum............... (subcop, 2)
Potentilla monspeliensis...............00005 (sparse)
Rumex Crispus. ..... 0... eee cece ewes (sparse)
Scutellaria lateriflora................ 0. eae (sparse)
Tya, xanthifoia, os wane cies a eens eee ee es (sparse)
Facies :-—

Spartina cynosuroides.

Carex cephaloidea.
Carex vulpinoidea.
Carex stricta.

QUADRAT XX XIII

WET MEADOW FORMATION: LATE ESTIVAL FLORAL ASPECT

Vernonia fasciculata.............. cc eee eens (sparse)
Rumex CTISPUS. «0... eee ee eee eee ee eee ee (sparse)
Facies :—

Eleocharis palustris.
Poa pratensis.
Carex vulpinoidea.
Carex cephaloidea.
Carex stricta.

14
12
12
10

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4
2

126 STUDIES IN THE VEGETATION OF THE STATB

LEGEND
4» =Antennaria campestris.
. =Aster multiflorus.
a =A. levis.
a’ =A. azureus.
we =A. paniculatus.
x — Amorpha canescens.
e, =Asclepias verticillata.
3% Anemone canadensis.
A * =Apocynum cannabinum.
BE =Bouteloua curtipendula.
x =Baptisia bracteata,

=B. leucantha.
=Brauneria pallida.
=Cicuta maculata.
=Coreopsis palmata.
=Ceanothus ovatus.
=Equisetum laevigatum.
=Erigeron ramosus.
=Gentiana puberula.
=Helianthus scaberrimus.
==Heliopsis scabra.
=Kuhnistera candida.
=K. purpurea.
=Kuhnia eupatorioides.
=Koeleria cristata.
=Lespedeza capitata.
=Laciniaria squarrosa.
=L. scariosa.

=L. pycnostachya.
=Lactuca ludoviciana.
=Meibomia illinoensis.
=Onagra biennis.
=Polygonum emersum.
=Panicum scribnerianum.
=Rosa arkansana.
=Silphium laciniatum.
=S. integrifolium.
=Solidago rigidiuscula.
=S., rigida.

=8. rupestris.

=S. nemoralis.

=Stipa spartea.

=Salix fluviatilis.
=Teucrium occidentale.
=Vernonia gigantea.
=Viola pedatifida.

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STUDIES IN THE VEGETATION OF THE STATE

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“ Rees we Ye Se ve S00 3 yea ee Dr)
Ber ty < Soe? it Se No fo oa vu ed rae oe
Path + steered SO O9e od? ett tg) eee Se mA
- O+ + “a god oU00 4 gro ates vee Yeu tay sarod
et +S 63S oe) to ye ¥® So were © Oe L vas uo Pte
Greer tte a ee, 0 OO oto & 2 fee 9 You YS Oey
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: Soe Go A 0? wee? OUgY e@
<<»: tbe 2 | ESeesey o Yo, oh Bette See
© + EA o Oyo, oO de vou Bevo “ee,
: Paes 2 8 . 0 of Ue wed oer Bo
ce +90 < Ven wee © 2 om oft, 0° ofiars
ae ob eles ened oe ort eg Seige
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+ + + too > U StS) eo *% eu mite vege
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re ratg gees ute we, sfu,8 Uo FOKe oo
‘i es 2 0 ONS ok
po 2 pnke aa

STUDIES IN THE VEGETATION OF THE STATE

130

et toh) Ue be Op POL TET
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To aN hy ONTe ST See + +58
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SO et? ee SENS tot eee tual Baw so, =e a3 OOS Le oe
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AE yO Othe BS Wott Bo ES O< yo? FOR UE > Vek UO. Sa, F ‘Ona e!
HE ot a on et + et Fo ee tg ty" Bee ok KR RTC se se SASS OF

XII

STRUCTURE OF THE FORMATION

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SA: p< 2 ean 2Eo1 3< TUT AT SO
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XVI

STUDIES IN THE VEGETATION OF THE STATE

XVII

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Bi SEEe 3° y Petar ies : RPE NL KOE
Tey hte Age re . <r & a .
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SAE Seo tS

132 132

Bd

XVIII

STRUCTURE OF THE FORMATION

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XXII

STUDIES IN THE VEGETATION OF THE STATB

134

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| SES ie Se 44 SE CEN erat ot) ein Ogee Re PF ag

STRUCTURE OF THE FORMATION

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fe aegh e is o Sohne % WD op ts
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a ee pe Oo nen wo a

186

STUDIES IN THE VEGETATION OF THE STATE

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XXXIII
Vv' |
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Vv
Vv ad

STRUCTUBE OF THE FORMATION

PHENOLOGICAL RECORD OF SPECIES GROWING IN
PRAIRIE FORMATION

137

a { ‘

gel, (a. [ak

#8 | Pe | alya ious

OO |eies
, eel ae Hal | Hiss

z ee | HS | d8| G3 | eS | eas

Slee |e sa? | ae

Acalypha virginica ........... 1899}..... 6-26| 7-20) 60 | 9-11] 30].....
Acalypha virginica ........... 1900 | 4-28) 6-28] 8-1 | 70 | 8-27} 40 |10-12
Acerates viridiflora ivesii..... 1900 ]..... 6-13| 6-23] 16 | 9-5 |..... 9-5
Acerates viridiflora linearis... | 1900|.....] 6-13] 6-29) 16].....].... -| 9-5
Agrostis alba................. 1899]..... 6-15} 6-21) 48 | 7-25].....).... i
Agrostis alba...............5. 1900} 4-4 | 6-21) 6-1 | 25].....}..... 7-25
Agrostis hiemalis............. 1899]..... 6-4 | 6-10} 20] 6-26] 15].....
Agrostis hiemalis............. 1900} 3-26] 5-19] 5-24] 21) 6-6 | 20] 621
Allionia nyctaginea ovata..... OOO cd aceica ae See pared [eases 4 es ere
Amaranthus graecizans....... 1899]..... 6-10] 7-17} 60 7-17} 60].....
Amaranthus graecizans....... 1900} 4-23) 5-17} 6-6 | 120 | 6-9 | 125 | 7-20
Amaranthus torreyi .......... 1899}..... G28 | sesacsiel e's osceilachastel stented [354 25%
Amaranthus torreyi .......... 1900| 4-14] 6-21) 8-19) 78 | 85 | 60] 9-10
Ambrosia trifida.............. 1899]..... 7-29] 8-22) 35] 9-9 | 221].....
Ambrosia trifida.............. 1900} 4-5 | 8-4 | 824) 35/91 | 28) 9-25
Amorpha canescens .......... .1899}..... 6-19} 7-5 | 21 | 8-5 | 30] 9-29
Amorpha canescens .......... 1900 | 4-30} 6-18] 6-28] 21 | 7-25) 25] 9-20
Andropogon furcatus......... 1899]..... 7-25| 8-5 | 30] 8-16) 26]..... :
Andropogon furcatus......... 1900] 4-21} 7-23] 8-20) 40 | 8-25) 35) 927
Andropogon scoparius . ... | 1900} 4-21} 7-20} 8-20] 45 | 8-20] 30 | .9-17
Anemone canadensis... 1899}..... §-22| 5-30} 38] 7-15) 25].....
Anemone canadensis... 1900} 4-10] 5-11] 5-25] 30] 6-21; 25] 7-30
Anemone caroliniana. . 1899} 4-8 | 4-24] 4-27) 15].....)...../.....
Anemone caroliniana. . ... 11900] 4-5 | 414] 4-25) 30 | 5-5 |..... 6-6
Anemone cylindrica .......... 1899]..... 6-12] 6-24) 18 | 8-14] 20].....
Anemone cylindrica .......... 1900| 4-4 | 6-11] 6-16) 11] 7-10] 15} 7-25
Antennaria campestris........ 1899}..... 4-20; 5-1 | 25] 5-17) 28]..... ‘
Antennaria campestris........ 1900} 4-5 | 4-17| 4-28) 18) 55 | 10] 5-15
Apocynum cannabinum ...... 1899]..... 5-30| 6-25) 60).....}.....1 ree
Apocynum cannabinum ...... 1900} 4-23| 5-30] 6-21; 40] 820; 45] 910
Artemisia gnaphalodes........ 1900 | 4-12; 8-14} 9-10} 40] 9-20) 30 | 10-20
Asclepias incarnata........... 1899]..... 7-10| 7-28} 45 | 9-4 | 25].....
Asclepias incarnata........... 1900 | 5-7 | 7-2 | 7-16} 45 9-1 | 28} 980
Asclepias obtusifolia.......... 1900}..... 5-30| 6-8 | 12] 8-1 | 25] 7-19
Asclepias sullivantii.......... |1900]..... 6-13] 6-23; 22] 85 | 25] 9-15
Asclepias syriaca............. 1899]..... 6-14} 6-26] 44 | 8-25) 25].....
Asclepias syriaca............. 1909 | 4-27 6-23; 30; 9-5 | 25] 9-25
Asclepias tuberosa............ 1899}..... 6-18} 6-26} 35 ].....4.....]. sean
Asclepias tuberosa...........- 1900 | 4-29] 6-13] 6-25) 34 | 829! 30] 9-15
Asclepias verticillata ......... 1899)..... 6-23; 7-5 | 60] 8-12) 45].....
Asclepias verticillata ......... 1900 | 4-17] 6-16] 6-27; 50] 8-27] 35 }10-1
Aster azureus ..............6- 1899{..... 9-13} 9-25; 30/103 |.....[. mae?
Aster Azureus ........--s0seee 1900 | 3-27}. 9-17/10-2 | 40 |10-10| 25 [11-1
Aster levis 2.0.2.0... cece cece eee 1899]..... 9-16} 9-27) 28 | 9-29} 20].....
Aster levis ........... eee eee 1900} 3-27 9-17 |10-2 40 |10-10} 25 |11-5
Aster multiflorus............. | 1899|.....} 8-14] 9-25) 60) 9-22) 40].....
Aster multiflorus.......:..... [19001 41 | 8-24| 9-29; 70 | 9-20| 45 [1025

1388 STUDIES IN THE VEGETATION OF THE STATE

PHENOLOGICAL RECORD OF SPECIES GROWING IN
PRAIRIE FORMATION —Continued

ee a be

‘ a q Ada
a8 | ie | ae gs 28 | 38 | aed
22) 98 | aE | 28 | 2a | we |2o8
20/43] #3) 28) ee] 62 | Sey
ola a" pas ae ee ieee

Aster oblongifolius ........... 1899]..... 9220 5a | seven oie sale|ineaa ale cect
Aster oblongifolius ........... 1900}.....) 9-10} 9-25] 35 |.....].....J.....
Aster paniculatus............. 1899)..... 9-7 | 9-23; 45 |10-10} 29 ].....
Aster paniculatus............. 1900} 3-31] 9-10}10-2 | 40 /10-15! 40 | 10-30
Aster sericeus.........../.... | 1899]..... 9-7 | 9-20} 29.} 9-25].....}.....
Aster sericeus.......... ... | 1900} 4-8 | 8-27] 9-15} 40 | 9-20] 40 | 10-25
Astragalus carolinianus. 1899}..... 7-10) 7-18} 20 | 8-5 18 Fsewes
Astragalus carolinianns....... | 1900} 3-24} 7-6 | 7-20} 40 | 9-1 25 | 9-10
Astragalus crassicarpus....... 1900). 226 sdswes ol ev eae ees 6-30} 30{ 8-10
Baptisia bracteata............ 1899]..... §-14} 5-22} 18 | 9-4 |.....).....
Baptisia bracteata............ 1900} 4-16] 5-4 | 5-12] 16 | 8-20] 20] 7-16
Baptisia leucantha............ 1899]..... 6-17| 6-26] 16 | 9-4 |.....].....
Baptisia leucantha............ 1900} 4-15] 6-23] 6-11] 27 ] 7-25] 15] 830
Bouteloua curtipendula....... 1899|..... 7-5 | 7-13] 24 ].....].....,.....
Bouteloua curtipendula....... 1900 | 4-24] 6-27| 8-1 40 | 8-25; 35 110-10
Brauneria pallida............. 1899)..... 6-18] 6-26} 40} 85 | 24).....
Brauneria pallida..:.......... 1900} 4-14] 6-8 | 6-22; 35 | 7-10] -5 | 7-25
Calamagrostis canadensis..... 1899}.....]..... C37) EF eee eee carters (eae
Calamagrostis canadensis..... LOI ]..... 6-4 | 6-11] 15} 6-21} 10] 7-1
Carduus altissimus ........... 1 46} 9-4 | 29].....
Carduus altissimus ........... 40 | 8-30} 33 | 10-10
Carex cephaloidea............ 14 | 5-31} 25 | 6-25
Carex festucacea............. 30 } 6-10).....J.....
Carex festucacea............. 20 | 5-30} 30 | 6-25
Carex meadii ................ 14 | 5-30] 21 ].....
Carex meadii................. 20 | 5-20; 12] 69
Carex pennsylvanica 12 | 5-20) 20].....
Carex pennsylvanica ; 11 | 5-16; 25) 526
Carex stricta............. es 24 | 5-20; 10] 6-19
Carex vulpinoidea............ 20 | 6-19} 25 ].....
Carex vulpinoidea............ 20 | 6-4 30 | 6-30
Cassia chamaecrista 58 | 8-16] 40].....
Cassia chamaecrista 65 | 8-14] 40] 9-10
Ceanothus ovatus............. 6-15} 22 | 10-10
Chastochloa glauca........... 60 | 7-17) 60].....
Chaetochloa glauca........... q 80 | 6-28) 70| 8-1
Chaetochloa Viridis........... 70 | 7-17} 50].....
Chaetochloa viridis ........... 120 | 6-25) 95 | 8-25
Chenopodium album 90 | 7-5] 60].....
Chenopodium album 125 | 6-20} 120 } 10-30
Chrysopogon avenaceus....... 1899}..... 8-21; 9-1 30 | 9-4 25 |.....
Chrysopogon avenaceus....... 1900 | 5-5 | 8-15] 9-1 35 | 94 | 22 {10-15
Cicuta maculata.............. ‘OT 3519-6 | 25].....
Cicuta maculata.............. 35 | 8-25] 35 | 9-30
Comandra umbellata 26 | 6-27).....].....
Comandra umbellata 31 25 | 6-10
Convolvulus sepium ...... a 10. Piss ccs| ess esas
Convolvulus sepium .......... 90 | 7-25] 45 |10-25

STRUCTURE OF THE FORMATION

PHENOLOGICAL RECORD OF SPECIES GROWING IN
PRAIRIE FORMATION— Continued

139

a}, a pe
Be Eg | q Ag
#9 ag = ag |]ua Pn
eAn| 2 | so] Sd |] 22 | OS [due
gas) Be | ee | 2 1 Be | gh |Sc8
ms = a5 a we Oh |e
# (283! Fa | ke gS | 58 | 5 | 92s
mb {8 ie} a <>) Au

Coreopsis palmata............
Coreopsis palmata............
Cornus asperifolia............
Cornus asperifolia............
Corylus americana............
Corylus americana............
Cuscuta paradoxa ............
Cuscuta paradoxa ............
Delphinium carolinianum.....
Delphinium carolinianum.....
Eatonia obtusata..............
Eatonia obtusata .............
Eleocharis palustris...........
Eleocharis palustris...........
Elymus canadensis ...........
Elymus canadensis ...........
Eragrostis pectinacea.........
Eragrostis pectinacea.........
Erigeron ramosus ............
Erigeron ramosus ............
Euphorbia corollata ..........
Euphorbia corollata ..........
Euphorbia glyptosperma......
Euphorbia nutans ............
Euphorbia nutans ............
Falcata pitcheri ..............
Falcata pitcheri ..............
Fragaria virginiana...........
Fragaria virginiana...........
Fraxinus lanceolata ..........
Fraxinus lanceolata ..........
Galium tinctorum............
Gaura biennis,................
Gaura biennis................
Gentiana puberula............
Gentiana puberula............
Habenaria bracteata..........
Habenaria leucophaea ........
Helenium autumnale.........
Helianthus annuus ...........
Helianthus annuus ...........
Helianthus grosse-serratus.....
Helianthus grosse-serratus....
Helianthus maximiliani.......
Helianthus maximiliani.......
Helianthus scaberrimus.......
Helianthus scaberrimus.......

140 STUDIES IN THE VEGETATION OF THE STATE

PHENOLOGICAL RECORD OF SPECIES GROWING IN
PRAIRIE FORMATION— Continued

—2 a {¢,

w/a} a@ | A ja

SE | we | de | So | 88 | oe loos

352) 32 | 2) 22 | Fe | oe |ec8

fla] ° | 2° | 28) BF | Be ae

Helianthus tuberosus......... 1€99]..... 8-8 | 8-21] 48}; 91 |.....
Helianthus tuberosus......... 19UU | 4-6 | 8-7 | 8-27! 45] 9-1 | 35 |10-15
Heliopsis scabra.............. 1899}|..... 7-13| 7-28} 75} 8-1 ]...../.....
Heliopsis scabra.............. 1900 | 4-21] 6-29] 7-14} 70 | 7-29] 60 |10-10
Hieracium longipilum ........ 1899 ]..... 7-27) 8-8 20 | 8-14) 20].....
Hieracium longipilum ........ 1900} 4-14] 7-10{ 7-25! 40] 7-29] 25] 8-27
Iva xanthifolia............... 1899 ]..... 8-16) 9-1 30 | 9-4 TE fecias
Iva xanthifolia . 1900} 4-5 | 8-15] 9-5 | 35] 9-2 | 25] 9-15
Juncus tenuis. Sees | OOO I ease arai begs aaves Ihave aera [econ 6-241 40 ].....
Juncus tenuis................. 1900 | .4-16] 5-20) 5-25] 128 | 6-1 | 120] 7-1
Koeleria cristata.............. B99 Fis cs heaeed 5-20); 25] 6-10] 20].....
Koeleria cristata.............. 1900} 4-10] 5-22} 5-27; 10] 6-8 |..... 6-19
Kuhnia eupatorioides,......... 1899 ]..... 8-16) 9-4 | 38] 9-4 | 26]....,
Kuhnia eupatorioides.......... 1900] 5-5 | 7-14] 8-21] 79 | 8-20} 40 ]101
Kuhnistera candida........... 1899|..... 6-26} 7-5 28 | 8-14} 25].....
Kuhnistera candida........... 1900} 4-23] 6-18) 6-29} 23 | 7-15| 30] 8-15
Kuhnistera purpurea......... 1899]..... 6-26; 7-5 | 28 | 8-14] 25].....
Kuhnistera purpurea......... 1900 | 4-23] 6-22/ 6-30} 35 | 7-20] 33] 890
Laciniaria pycnostachya...... 1899].....}..... Bab [a | ctv whee Peseta
Laciniaria pycnostachya...... 1900 | 5-12] 7-20] 8-10] 30] 8-28] 30] 9-95
Laciniaria scariosa............ 1899]..... 8-14] 9-4 35 | 9-15] 20].....
Laciniaria scariosa............ 1900} 4-24] 8-11] 9-1 38 | 9-15] 25 | 10-15
Laciniaria squarrosa.......... 1899}..... 8-5 | 8-20} 25 | 9-10).....].....
Laciniaria squarrosa.......... 1900]..... 7-10] 7-25] 38 | 8-20; 30] 9-15
Lactuca canadensis........... 1899]..... 7-22) 8-8 45 | 8-16; 40].....
Lactuca canadensis........... 1900 | 3-26] 6-29] 7-15] 60] 7-20] 60] 9-16
Lactuca Indoviciana.......... 1899]..... 7-9 | 7-30) 50} 7-30]...../.....
Lactuca ludoviciana.......... 1900 | 3-26] 6-16] 7-10} 50 | 6-25! 60] 8-20
Lactuca pulchella......... we 45 | 7-5 35 |.....
Lactuca pulchella...... me 45 | 6-27] 35] 8-15
Lespedeza capitata eat 25 | 9-11] 20].....
Lespedeza capitata 40 | 8-27} 30 | 9-25
Lilium canadense............. 12!) ss sieclveas ewces
Lilium canadense......... faeusls a eres eee 8-1
Linum sulcatum.............. 45 | 7-19! 38].....
Linum sulcatum.............. 60 | 7-14} 40] 9-15
Lithospermum angustifolium.. | 1899]..... 5-7 | 5-13) 18] 6-10] 35 ]..... :
Lithospermum angustifolium..|1900| 4-12] 4-22] 5-2 | 18/61 | 30] 81
Lithospermum canescens...... 1899}..... 5-2 | 5-6 28 Nicixa taatae sl wares
Lithospermum canescens...... 1909} 4-14} 427] 55 23 | 6-15} 25] 81
Lobelia spicata hirtella..... as. {1900]..... 6-25 | 7-9 20 ciexarcllas's all aoe
Lycopus americanus.......... 1899]..... 7-12] 7-28} 58 | 8-25) 35 ].....
Lycopus americanus.......... 1900] 4-12; 6-28] 7-14] 55 | 8-20] 38 |10-20
Lythrum alatum,............. 1899]..... 6-17| 6-30} 60/85 |] 40/].....
Lythrum alatum.............. .|1900]..... 6-14] 6-23} 55 | 7-5 40 | 8-15
Meibomia canadensis ......... 1899]..... 7-14) 7-25} 35] 8-16] 28 ].....
Meibomia canadensis......... 1900| 5-5 | 7-25; 86 | 35] 828] 30] 9.25

STRUCTURE OF THE FORMATION

PHENOLOGICAL RECORD OF SPECIES GROWING IN
PRAIRIE FORMATION—Continued

141

wo KF 12
geia | #8 {a3
ag 2 ae se Be lye log
g23| 88 | 2o | aS | #2 | o8 | Bes
Qa>| OF Ag ee Qs Sa 4 Al

§ /ER2| Ge | 8 | gh) Fo | be | oes

mp la a |e |/4 [a [a [a
Meibomia illinoensis.......... 1899 ]..... 7-13} 7-25) 30] 8-14} 25 ].....
Meibomia illinoensis.......... 1900} 4-27) 6-22] 7-2 45 | 7-16; 40] 8-1
Mentha canadensis............ 1899}..... 7-10} 7-28] 70 | 8-25} 45)].....
Mentha canadensis............ 1900 | 4-12] 7-6 | 8-10] 75 | 8-10) 55 |10-L
Mesadenia tuberosa........... 1899]..... 6-23| 7-5 | 37] 8-5 |.....].....
Mesadenia tuberosa........... 1900} 4-7 | 6-18} 6-29; 25 | 7-20; 20] 7-28
Monarda fistulosa............. 1899}..... 7-15| 8-1 45 | 8-20} 30].....
Muhlenbergia racemosa....... 1899]..... 7-7 | 8-10] 68 | 9-1 80 fakes
Mublenbergia racemosa....... 1900} 4-18} 7-20] 8-25) 70 | 8-20} 40 | 10-10
Nabalus asper..............5. 8-14] 8-22; 28] 9-1 | 25].....
Nabalus asper................ 8-22} 30 | 8-27} 25 | 9-30
Onagra biennis..............05 8.5 45) 9-4 |] 30].....
Onagra biennis................ 7-22} 90} 8-5 60 | 10-1
Oxalis stricta...........0...65 5-22} 6516-9 | 60].....
Oxalis stricta................- 5-22] 80 | 6-15} 70 |10-20
Oxalis violacea......... BERT | 28 fase | conceals cas
Oxalis violacea....... 5-5 | 35 | 5-25) 25] 6-25
Panicum capillare...... 2 8-15} 40 | 8-25] 30].....
Panicum capillare............ 7-15| 55 | 7-20} 45] 9-10
Panicum depauperatum....... 1899].....J..... BQO aasveia le escore| oad veallle artes =
Panicum depauperatum....... 1900} 4-12} 5-19] 5-25; 12] 6-10; 20] 6-19
Panicum pubescens........... 1899]..... 6-5 | 6-12] 20 | 6-20].....].....
Panicum pubescens........... 1900 | 4-14} 5-22; 5-28} 18} 6-15} 25 | 8-15
Panicum scribnerianum ...... 1899]..... 5-22) 5-30]..... 6-8 |..... eaters
Panicum scribnerianum ...... 1900| 4-7 | 5-16) 5-26} 20) 6-25] 25 | 17-25
Panicum virgatum............ 1899 }..... 7-26| 8-8 | 25 | 8-25] 32].....
Panicum virgatum............ 1900 | 4-29] 7-24] 8-3 | 30 | 8-20} 25 |10-1
Phalaris arundinacea......... 1900}..... 5-30} 6-6 | 10] 6-10} 8] 6-18
Phleum pratense.............. 1899]..... 6-14} 6-19] 28 | 7-17} 18].....
Phleum pratense.............. 1900 | 3-24] 6-8 | 6-20] 26 | 7-7 | 30] 8-15
Phlox pilosa............00 000 1899]..... 5-26| 5-31) 31 | 6-25} 25 ].....
Phlox pilosa..........0.0.e006 1900 | 4-14] 5-17] 5-25) 35 | 6-25} 385 | 8-1
Physalis heterophylla......... 1899)..... G10) sc cxailccucafaprat sl aaade Peers
Physalis heteropnylla......... |1900| 4-28] 6-2 | 6-8 | 45) 8-1 | 3010-1
Physalis longifolia.... 1899|..... 6-26] 7-10} 45} 9-4 | 23 ].....
Physalis longifolia....... . | 1900] 4-28] 6-5 | 6-22}; 85 | 8-10) 60 | 10-20
Physalis virginiana var....... 1899|..... 6-8 | 6-15] 25 | 7-19].....).....
Physalis virginiana var....... 1900} 4-25} 5-23} 6-2 | 25 | 7-19]..... 7-25
Plantago major............... 1899 ].....]....- 6-26 |iss eal, corns feaecsle cess
Plantago major............066 1900) 3-23} 6-9 | 6-27) 70} 7-16) 45] 85
Plantago rugellii............. 1899]..... 6-5 | 6-30].....).....).....[. 008.
Plantago rugellii............. 1900] 2-23} 6-5 | 7-5 | 60} 7-1 | 45) 9-1
Poa pratensis...........+2+00 1899|..... 5-16} 5-24; 34/6-5 | 21].....
Poa pratensis...........0. eee 1900 | 3-12] 5-9 | 5-25} 30) 6-1 | 20] 6-15
Polygala verticillata.......... 1899]..... 6-21] 7-17} 60} 8-5 |.....}.....
Polygala verticillata.......... 900]..... 6-11] 6-29; 100 | 6-29) 90/].....
Polygonum emersum......... 1899].....}..... 7228 loos loa alleawes | yanes
Polygonum emersam......... 1900} 4-25) 7-20] 8-8 | 55 | 8-15].....].....

142 STUDIES IN THE VEGETATION OF THE STATE

PHENOLOGICAL RECORD OF SPECIES GROWING IN
PRAIRIE FORMATION—Continued

n 8 Be

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BES Se] 8 | sg] ge Sa aos

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Polygonum pennsylvanicum .. | 1899]..... 6-10] 6-26} 20 | 7-10] 20].....
Polygonum pennsylvanicum .. |1900}..... 6-5 | 7-5 95 | 7-1 90 | 9-20
Potentilla monspeliensis ...... 1899]..... 5-30; 6-15] 45] 7-5 | 30].....

Potentilla monspeliensis ...... 1900 | 3-24} 6-1 | 6-22} 70] 7-10} 60 {10-1
Psoralea argophylla........... 1899}..... 6-19] 6-26) 25 |.....).....4000..
Psoralea argophylla........... 1900; 5-8 | 6-2 | 6-18) 37 | 8-2 30 | 7-15
Psoralea esculenta............ 1900} 5-1 | 5-17] 5-22} 151] 6-10} 10] 619
Ps :ralea tenuiflora............ 1900}..... 5-30] 6-6 | 25 ].....f.......00..
Quercus macrocarpa.......... 1839 | 4-28] 4-28] 5-8 14 | 9-5 | 20 | 10-28
Quercus macrocarpa.......... 1900] 4-26} 5-2 | 5-8 | 13 | 8-27] 25 |10-15
Katibida pinnata.............. 1899|..... 7-13| 7-28} 45 | 8-25] 20].....
Ratibida pinnata.............. 1900} 4-14} 6-23) 7-20} 45 | 8-16] 30] 9-15
* hus glubra...s ss ccs s cee ceen j 20 | 8-25} 30] 9-29
Rhus glabra........... 24 | 8-1 25 | 9-25
Rous radicans................ | 1899].....] 6-L | 6-10]..... 9-25]}..... 9-22
hus radicans 12 | 8-20} 25 | 9.25
Rosa arkansana 40 | 8-10} 30 /10-10

R: sa arkansana............... 19U0 | 4-12} 5-20} 5-30] 60 | 8-15} 35 110-1
Ruellia ciliosa................ 1y00}..... 6-26] 7-13] 60] 8-15] 45] 9.30
Rumex altissimus............. 1899}..... 5-11} 5-30] 50 | 6-8 34 feo...
Rumex altissimus............. 1900} 5-26] 5-8 | 5-25] 30 | 6-7 26 | 7-10
Rumex crispus ............... 18y9|..... 5-29] 6-10; 44] 6-17] B0].....
Rumex crispus ............... 190U | 3-24) 0-24] 5-30} 36 | 6-12 40 | 6-29

Sambucus canadensis......... 1899] 5-1 | 6-15} 6-24] 30] 7-28} 30 |10-1
Sambucus canadensis......... 1900} 4-10} 6-9 | 6-22] 48 | 8-1 30 | 10-15
Salix fluviatilis............... 11899] 5-3 [53 15-7 |... fo... [0.0/0
Salix fluviatilis ss 40 | 10-15
Saiix humilis................. 20 | 9-29

Sa.ix huinilis............0..0. 15 | 10-1
Scirpus atrovirens............ 1899]..... 6-9 | 6-19} 20] 7-10] 20].....
Scirpus atrovirens............ 1900] 4-7 | 5-30] 6-11] 20] 6-16] 18] 8-14
Scutellaria laterifiora......... 1899]}..... 7-24} 8-8 45 | 9-7 30 |.....
Scutellaria lateriflora......... 1900] 4-15] 7-15] 8-15] 50] 9-1 35 | 10-10
Scutellaria parvula........... 190U}..... 5-10! 5-20] 30 | 6-1 20 | 6-27
Senecio plattensis............. 1899]..... 5-17| 5-22; 45 |] 6-10}.....4.....
Senecio plattensis............. 1900] 3-27} 5-5 | 3-10} 31 | 5-.3} 25] 611
Senecio integerrimus.......... TO0O lec sas Poseetll Ce acwtle aes 5-20} 20 |.....
Silene stellata................ 1BAY]..... 7-2 | 7-10} 26] 8-1 QU Vedas
Silene stellata................ 1900] 4-11] 6-25) 7-4 15 | 8-5 20 | 915
Silphiam integrifolium........ 1899 ]..... 7-7 | 7-296] 45 | 9-7 23 lacie
Silphium integrifolium........ 1900 | 4-7 | 6-28] 7-25] 601] 8-18] 35 | 9.30
Silphium laciniatum.......... 1899]..... 7-17| 7-26] 34] 8-16].....].....
Silphium laciniatum.......... i900} 4-14] 6-27] 7-19] 55 | 8-18] 30] 9-20
Silphium perfoliatum......... 1839]..... 7-17) 7-29} 32} 8-16} 30].....
Silphium perfoiiatum......... 19.0} 4-14) 7-7 | 7-25] 38 | 8-29] 30 | 10-20
Sisyrinchium angustifolium...|1899] ....| 5-8 | 5-13} 2516-10] 20].....
Sisyrinchium angustifolium... | 1.00] 4-14] 4-29] 5-5 | 25 | 5-20] 15] 67

STRUCTURE OF THE FORMATION

143

PHENOLOGICAL RECORD OF SPECIES GROWING N
PRAIRIE FORMATION —Concluded

aE a ee

. ga | 4 f# |lAd
ee | 4 | at} so| Be | oe (ots
Ba6| pe | gf | cB | az BlBoR
236| 22 | He | te | £8 | 38 Sak
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Solanum carolinense.......... 1899}..... 6-14] 6-26] 44] 825/ 25 ].....
Solanum carolinense.......... 1900} 5-3 | 61 | 6-26; 45 | 8-18] 30 {10-10
Solidago canadensis........... 1899]..... 8-16] 9-1 46 | 9-20] 30}.....
Solidago canadensis........... 1¥00} 4-7 | 8-4 | 8-25] 45 | 9-10] 35 |10-15
Solidago nemoralis............ 1900]..... 8-3 | 8-23] 40] 9-10} 30 | 10-10
Solidago rigida ............... 1899]..... 8-5 | 8-16) 55 | 9-15].....).....
Solidago rigida ............... 1900} 4-4 | 8-2 | 8-30} 56 | 9-10} 30 |10-10
Solidago rigidiuscula.......... 1900 | 4-14] 9-15) 9-25] 30 |10-1 25 | 10-25
Solidago rupestris............. 1899}..... 7-20] 7-29] 30 | 9-7 OBE ils. suai sve

Solidago rupestris............. 1900 | 3-27] 7-10] 7-23] 40 | 8-20} 25 | 10-1
Spartina cynosuroides......... 1899]..... 7-25| 8- 6] 45 |.....).....].....

Spartina cynosuroides......... 1900} 4-21] 7-5 | 8-10) 40 | 8-20] 25 |10-1
Sporobolus asper............+ 1899]..... 8-9 | 8-20] 30 | 9-1 25 |. aes
Sporobolus asper............-+ 1900} 4-28] 8-20] 9-1 25 | 9-5 | 25 | 10-10
Sporobolus heterolepis........ 1900 |vcsncfesces 8-23]..... 8-30] 20 ].....
Steironema ciliatum .......... 1899]..... 6-19) 6-26] 38 | 5-15].....].....

Steironema ciliatum .......... 1900} 4-14) 6-15} «-25] 30 | 7-25] 30] 9-41
Stipa spartea ..............005 18J)9]}..... 5-25] 5-30} 10] 6-l0} 10].....
Stipa spartea ................. 1900] 4-5 | 5-24] 5-28} 10];611{ 10] 6-19
Teucrium canadense.......... 1899]..... 6-24] 7-7 | 36] 7-29] 30 ].....
Teucrium canadense.......... 190 | 4-15] 6-17] 6-27} 60 | 7-25] 40] 9-10
Teucrium occidentale......... 1900 | 4-15] 6-18] 7-5 60 | 7-25] 40] 9-10
Thalictrum purpurascens..... 1899)..... 6-6 | 6-19] %4 | 7-30] 15].....
Thalictrum purpurascens..... 1900} 4-10] 6-5 | 6-11} 22 | 7-25] 251] 8-25
Tradescantia virginiana....... 1899 |..... 5-23; 5-30} 14] 619] 12).....
Tradescantia virginiana....... 1900 | 4-16] 5-11] 5-18] 17 | 6-5 12} 619
Trifolium pratense. ..... .... 199 | ascns se 5-24] €-15| 95 | 6-20] 90].....
Trifolium pratense............ 1900 | 3-12} 5-15; 6-1 | 120 | 6-¢ $0 | 10-30
Trifolium repens.............. 1899]..... 5-13| 5-31] 60] 6-L0} 50] ....
Trifolium repens.............. 1900} 3-12] 5-10] 6-1 70 | 625) 58 | 10-30
Vernonia fasciculata.......... a Ks o)2 eee (eee 8-10; 35 | 8-22) 30].....
Vernonia fasciculata.......... 1900 | 427] 7-10} 8-5 35 | 9-1 30 | 10-15
Vernonia gigantea............ 1899|..... 7-10| 7-28} 45 | 8-16} 30 ].....

Vernonia gigantea............ 1900) 4-25] 7-4 | 8-1 45 | 8-15] 35 |10-1
Verbena hastata.............. 1899]..... 7-12) 7-25} 50] 8-10].... Jo...
Verbena hastata.............. 1900} 4-12} 6-29] 7-9 | 50 | 8-25] 40 |10-15
Verbena stricta............... 1899]..... 6-14} 7-10] 65 | 7-31) 30 ].....

Verbena stricta............... 1900] 4-6 | 611} 7-4 | 60] 81 40 | 9-1
Vicia americana.............. 1899 }..... 5-10} 5-22; 25 |] 6-10] 25 ].....

Vicia americana.............. 1900; 47 | 5-4 | 5-"%] 30] 6-10} 22] 7-1
Viola obliqua................. 1899]..... 4-23; 5-1) 16} 5-30! 40] ....
Viola obliqua................. 1900 | 3-24] 4-18} 4-_.} 28 | 5-19} 30] 625
Viola pedatifida............... 1399]..... 5-1 | 5-8 14 | 530] 30].....
Viola pedatifida............... 1900} 4-14] 4-27] 55 | 18] 5-25] 35] 6-27
Zizia aurea. ..........2. 000 1900} 4-14] 5-14] 5-24] 28 | 7-5 30} 8 3

] %y
hh

UNIVERSITY -OF

= NEBRASKA 20>
BOTANICAL SURVEY: OF: NEBRASKA

x

-LINCOLN, NEBRASKA ”
PUBLISHED BY THE. SEMINAR
1902.

~ADistributed October 31, 1902)

STUDIES

IN THE

VEGETATION OF THE STATE, IT.

Wooprvurr-CoLLins PRINTING Co.,
LINCOLN, NEBRASKA

THE RELATION OF THE WATER CONTENT OF THE
SOIL TO CERTAIN PLANTS, PRINCIPALLY
MESOPHYTES

By GErorGE G. HepGcock
INTRODUCTION*

A plant is either modified, or destroyed by its environment
whenever this is changed even in the slightest degree, and,
since the physical conditions vary constantly, a plant must
be an adaptive organism in order to meet all these require-
ments. Being originally an aquatic structure, in order to
become an intense xerophyte, it must have undergone a long
series of small changes in function and structure as it passed
over from the one type to the other. The mesophyte pos-
sesses a structure which prevents it from thriving in ex-
treme conditions of dryness or moisture. In periods of
drought it may adapt itself in a certain degree to dry condi-
tions, but lacking either a sufficient store of moisture in its
tissues or the means of conserving what it has, it perishes
long before the true xerophyte.

The mesophyte, since it grows in a substratum of soil, is
necessarily affected by the water content of the soil, and by
the varying conditions of soil moisture. In times of drought
it is quite noticeable that plants of one species die sooner
than others of a different species, and certain individuals
perish sooner than others of the same species, although
growing in the same soil plot. The observation of these
differences in the drought resistance of plants led to the ser-
ies of experiments the results of which are given in this pa-
per. Although the study has been made from an ecological

*Accepted by the Faculty of the University of Nebraska as a thesis
for the degree of Master of Arts, June, 1901.

6 STUDIES IN THE VEGETATION OF THE STATE

standpoint, it is difficult to decide whether the results are of
most importance to plant physiology or to plant pathology,
since both are concerned either directly or indirectly in the
problems involved. The whole question of resistance to
drought is intimately connected with the ability of proto-
plasm to withstand the effects of unfavorable stimuli. Fur-
thermore the problem resolves itself into inquiries as to the
proper amount of light, heat, water, etc., necessary for the
natural development of the plant. When a plant does not
receive the stimuli necessary for its growth and maturity, it
soon passes over into a condition which may or may not be
pathological, but which directly concerns the plant pathol-
ogist, as well as the plant physiologist. The former is con-
cerned with conditions which lower the vitality of the plant,
the latter, with those which are necessary to growth and
maturity. Itis hardly possible to draw the line between
health and disease, or to establish the proper amount of
light, heat, moisture, etc., requisite for a healthy plant,
since the quantity of each may vary not only with the inher-
ent nature of the species, but also with its adaptability.
When a mesophyte dies from drought, there is always some
water remaining in the soil which is not available for the
use of the plant. This has been called ‘‘non-available”’
water, in distinction to the physiological water of the soil
which is available for the needs of the plant. There are so
many factors and combinations of factors, both physical and
biological, that may vary the limit of the amount of non-avail-
able soil water that only a few of ti.ese can be considered in
one series of experiments. The work that has been done is
included in the following outline. No attempt will be made
to enter into a complete discussion of any one topic, for that
would require the results of many years of investigation.
The following outline contains the subjects investigated:

I. Water in Different Soils.

1. Physical Water..
2. Physiological Water.
3. Non-available Water.

WATER IN SOILS 7

Ii. The Relative Amount of the Water in the Plant and
in the Soils.

1. The amount of water in healthy plants, and in
the soil in which they grow.

2. The amount of water in plants and in the soil
when they are wilting under measured physi-
cal conditions.

3. The amount of water in plants at or near the
death point when dying from drought, and the
corresponding amount of non-available water
in the soil.

TW. The Limit of Physiological Water, (non-available
water). How affected?

By increased heat and light.

By increased humidity.

By decreased humidity.

By decreased light.

By lowered temperature.

By high temperature.

By different soils.

How varied in different species and individuals?

IV. Drowehit Effects. The Manner in Which Mesophytic

Herbs Die from Drought.

I. WATER IN DIFFERENT SOILS.
A. METHODS OF EXPERIMENTATION, ETC.

1. Soils. The soils used in the investigation were brick
clay, quartz sand not quite pure, loam, loess or subsoil,
saline soil from the saline lands near Lincoln, and humus
consisting largely of leaf mold. The mechanical analyses
of these six soils have been appended to this paper in the
form received from the assistant agriculturist of the Nebraska
Experiment Station, to whom they were sent for analysis.
The experiments in attempting to grow plants in the native
saline soil proved the futility of such efforts. Only salt-
basin plants thrived in it, then only when slightly diluted
with loam. The results noted in the summary appended are
from a soil consisting of one part saline mixed with three
parts of loam. All soils were sifted with a screen possess-

OT Sx OV 28 NS

8 STUDIES IN THE VEGETATION OF THE STATE

ing a quarter inch mesh. In experiments in the plant-house,
the suils were usually looser than found in nature. It was
impossible during the length of time used for experimenta-
tion to measure the degree of hardness, yet this must de-
termine to a greater or less degree the extent and course of
the rootlets of the plant. Such being the case, the hard
soil may limit the extent of a plant’s roots and become an
direct factor in times of drought because it may thus hasten
the death of the plant by limiting its ability to secure water.
In order to roughly estimate the condition of the soil, it has
been indicated in the summary of results as loose, medium,
and hard in density. In case of plants grown for experi-
mentation, the soil being loose at first, most of them had an
opportunity to become well rooted before it became hard,
and as a result the hardness of the soil is not considered as
a factor affecting the death of the plants to an appreciable
degree.

2. Water in Soils. Since the amount of water a soil may
hold is measured by the space between the particles of soil,
the water capacity was determined for each of the six soils
used by a simple experiment which is described under Phys-
ical Water. The amount of physical water present in the
soil was determined by taking samples from the pots with
a tubular soil sampler. These were weighed at once to pre-
vent error from evaporation, and subjected to a heat of
212° F. for about 24 hours; then the per cent was determined
from the loss in weight. The evaporation of slight amounts
of volatile organic water was not taken into consideration in
the results. The amount of’ water in the soil not available
for the plant was found in the same way as the physical
water, except that it was determined when the plant was
near the death point, as evinced by the condition of the
organs of the plant. The exact time when a plant can no
longer get water from the soil is difficult to decide, but the
rule followed in most cases was to take the soil sample at
the time the youngest leaves of the plant wilted strongly,
though in many cases the plant was actually dead at the time of
the estimate. This will account for most of the irregularities

WATER IN SOILS 9

shown in the results. The physiological water was finally
determined by deducting the per cent of non-available water
from the per cent of physical water in the soil at the time
the process of drying out began. The plants were grown
for experimentation in three and four inch porous pots. In
order to control the evaporation, the three inch pots were
set in soil and kept there during the whole time of exper-
imentation. In order to prevent too rapid loss of water, the
four inch pots were placed inside painted pots, during the
period of drought to which they were subjected in determin-
ing the non-available water. All soil samples were taken
from the soil in the lower part of the pot, in the vicinity of
the roots, the upper part of the soil being discarded, as it
contained very few roots. Owing to the great number of
pots used in experiments it was impossible to keep a daily
record of the physical water in the soilof each. In the
comparative plots, soil samples were taken from one pot in
each condition, and tbe water in the others estimated from
this record. The non-available water was always determined
by taking a soil sample from each pot used in the experi-
ment.

3. Water in Plants. In determing the amount of water in
plants, the plant was carefully removed from the soil, the
small particles of soil adhering to the roots were shaken off
where possible, and the plant quickly weighed. It was then
subjected to a heat of 212° EF. ina drying oven from 8 to 24
hours, depending upon the size of the plant. The per cent
of moisture was then determined from the loss in weight.
All weights both of plants and soil samples were made with
a laboratory balance sensitive to one milligram.

4. Physical Conditions. In order to grow plants under dif-
ferent physical conditions, four plant cases with glass panes
overhead and in the sides were constructed and placed in
the south windows of the laboratory. One of these had a
connection with the outside air and by this means was kept
at a lower temperature must of the time, the exception
being the last week of the experiment. This case is desig-
nated as Case I. The light, though less intense than that in

10 STUDIES IN THE VEGETATION OF THE STATE

the plant house, was nearly equal in intensity to that of
Case III and Case IV. The soil moisture was kept at a good
growing per cent, usually at from 12 to 25 per cent. physical
water. Case II had the direct sunlight shut out. This re-
duced the light to less than one-hundredth of that of full
noon-day sunlight. Other factors were kept near the nor-
mal. Case III was intended to be a xerophytic chamber but
usually it was nearer normal than otherwise. Case IV was
regulated so that the air was almost constantly humid. The
soil likewise was kept wet, generally with from 20 to 30 per
cent of soil water. In another window, in the air of the
laboratory, was a plot designated as Lab. in the records.
The air of this plot during the time of experimentatiun was
almost constantly deficient in moisture. The averages of
temperatures in Case II, Case III, Case [V, and Lab. were
about equal.

In the plant-house, plants were grown under five measured
sets of physical factors. Those grown under the full light
are designated in the species lists as P. H. These were
kept in good growing condition with a soil moisture of from
12 to 25 per cent of physical water. P.I, P. IL, P. III and
P. IV were four plots under essentially the same air condi-
tions as the P. H. plot, except that the first two were shaded.
P.Iand P. III were kept at a high per cent of physical soil
water, 20 to 35 per cent, but P. If and P. [IV were kept ata
low per cent.

5. Temperature and Humidity. Air temperatures were taken
with a psychrometer in the plant-house and with stationary
wet and dry bulb thermometers in the plant cases. The
relative humidity was calculated from these readings. The
maximum and minimum thermometer was used for record-
ing the extremes of temperature in the plant-house. Soil
thermometers were kept constantly in one pot in each plot.
Readings of all factors were taken three times daily, morn-
ing, noon, and evening, at or near 8 A. M., 12M, and 4 P. M.
For convenience in comparing the records with those of the
local U. S. Weather Bureau all temperatures are given in

Fahrenheit.

WATER IN SOILS 11

6. Light. The intensity of the light was estimated three
times daily in each plot until a ratio was established for each
plot. This ratio varies somewhat, being relatively greater
indoors on cloudy than on sunny days. The method used in
estimating light is the photographic method. Strips of
solio paper pasted together in a ribbon are placed on rollers
in an instrument invented by the author. The ribbon may
be exposed any number of seconds by means of a shutter in
the bux which contains it, and then rolled back in the dark
until needed for making the estimation. Solio paper if ex-
posed in full sunlight at noon during a series of increasing
periods of time as 2, 3, 4, 5 seconds, will print a series of
colors changing from a light pink for the shortest exposures
to a rich red brown for an exposure of 15 seconds. Sucha
series of colors printed at meridian noon is taken for a daily
or local standard, and the colors obtained by time exposures
in each locality were matched with those of the standard.
From this the per cent of light at the time of the exposure
was estimated. The daily standard of sunlight varies dur-
ing the year with the sine of the angle of the sun’s elevation.
Some day of the year must be taken asa fixed standard.
June 22 being the time of maximum light is taken in this
treatise as the fixed standard, and the light at meridian noon
for that day is called 100. In figuring light intensities by
this method, it was necessary to estimate each by the
light standard of June 22, in order to compare the light of
different days in different plots with each other. This was
done as follows: Suppose observations of light are taken
February 20, morning, noon, andevening. The noon expos-
ure is one of full sunlight, and its per cent of the fixed stand-
ard, June 22, is calculated as follows: From the astronomi-
cal tables of elevations for Lincoln prepared by Professor
Swezey, the angles of elevations are as follows:

June 22, angle 72.6°
Feb. 20, angle 38.4°
Turning to trigonometric tables for natural sines the
sines of these angles are:
For 72.6° .9542
38.4° 6211

12 STUDIES IN THE VEGETATION OF THE STATE

The ratio of the sines obtained by dividing the latter by
the former is 65, that is, the light intensity on February 20
is 65 per cent of that of June 22. Again if the exposure
taken for 15 seconds in the morning of February 20 equals
in color that of 7 seconds at noon the same day, its intensity
is 7s of 65 per cent or 30.3 per cent. This method of
measuring light is not without error, but until we know
more of the nature and effect of the sun’s rays, it is an ap-
proximate method of measuring those rays which are most
stimulating to the chlorophyll of the plant.

The present investigation was suggested by Dr Clements,
under whose direction it has been carried out. The writer
is greatly indebted to Dr. Bessey and Dr. Clements for help
given in the course of experimentation.

B. RESULTS OF INVESTIGATION

The results of the series of experiments carried on in the
laboratory and the plant house from December, 1900, to June,
1901, are here considered in nearly the same order as that
of the outline given in the introduction. With these data
are incorporated the observations made in the fields near
Lincoln during a short period of excessive dryness in the
month of August, 1900.

1. Water Capacity of Soiis.

The water capacity of different soils varies directly with
their porosity, tbat is, with the air spaces they contain. This
is dependent upon the fineness of the soil particles. How-
ever, this is a subject that cannot be fully discussed ina
treatise of this nature. In order to know the comparative
amount of water, each of the six soils used in experimenta-
tion was subjected to the following experiment. Pulver-
ized soil of each kind, namely, sand, saline, loam, clay, loess
and humus, was placed in a drying oven at a temperature of
250° F. for 48 hours. Measured quantities of each were
weighed and placed in flat crystallizing dishes of approxi-

WATER IN SOILS 13

mately the same size. Distilled water was then slowly ad-
ded to each to the point of apparent savuration. The humus
probably was not thoroughly saturated owing to the resist-
ance of the numerous capillary air spaces contained in the
organic matter. The dishes were placed in similar physical
conditions and the water allowed to evaporate from the soil,
in order to determine the daily rate of evaporation. After
continuing the process for several days the soils were again
dried in an oven under the same conditions as before except
that they were not pulverized. The experiment of evapora-
tion was now repeated, using the hard soils, with the excep-
tion that this time they were allowed to become air dry. The
first experiment was performed in the laboratory under dry
conditions, the second under more moist conditions in the
plant house. The following tables give the data obtained:

Water Capacity of Soils (in per cent of weight)

SOIL LOOSE HARD
San jn duewlooste beens ted eeaeion Gas Beers eeees 125 12.0
TGOAI sc 5.2. cov aschater bebo warns bee Seema Sasha eae eee 39 9 33.6
Sahne:...345. vee eese-s od. as hme Seaeaeitdee 2 Mame A apes 40.8 38.6
CHA G ecciasics otiaaceecce encase aw eele Wiel Kerccans an waNing 32 5 27.6
WiQ GSS soo asin roto tionties sisi a paceainaes eee vie Bevo lene 37.1 303
UMS i sche wisest ois. seul eve seRnee aie aes rear Ma aoe 33.6? 28.7?

Shrinkage of Loose Soils on Becoming Hard as Indicated by the
Difference in Bulk.

SOIL LOOSE HARD SHRINKAGE
Sands csvcads pane ggeata ue teauiers 510 c.c 500 c.c. 20%
WoO athe ce eye seateeinn e atte F sieees 510 cc, 460 c.c. 9.8%
Dalin®s:, «arses sen ess sens sales 600 c.c. 555 c.c. 75%
Clay..... SERRE tees e224 SNES 600 ce. 540 c.c. 10.0%
H0C88 0 23 cides gaauwe see sesaa yes 600 c.c. 552 cc. 8.0%
FMM). oc aie nog ee be ss 4 aanee dees 600 c.c. 585 c.c. 4.2%

14 STUDIES IN THE VEGETATION OF THE STATE

Per Cent. of Space Occupied by Water in Soils.

SOIL LOOSE HARD
Banded oy ties gue cadet AGA ee 27.1% 25.8%
TLOD seis vn oie cca d voted een a: “Sane R 60 8% 55 8%
DARING ca tut ia ene y's ede Lea moe OTA 59.2% 58 2%
O1By ico irocam dh ee eas ones 5 HE RNREERIE ORES 48.6% 46 2%
VOG8S 4 sideman asy Seeker a gs Ame eee. Kisses: 56 9% 50.5%
Hamuss 22s. asanses fiveceksdaantnd sania 44.9%? 39.0%?

It will be seen from the above tables that the water ca-
pacity of both loose and hard soil in order of the amount
contained is as follows: saline, loam, loess, humus, clay,
sand, when estimated by the comparative weights. If the
water capacity is estimated by the per cent of space occu-
pied, the series is as follows in loose soil: loam, saline,
loess, clay, humus, sand. The order of shrinkage in be-
coming hard is slightly different being as follows: clay,
loam, loess, saline, humus, sand.

The loss of water from the loose soil by evaporation, given
in grams for each period of 24 hours, and for the final 6 days
is given below.

Evaporation of Water from Loose Soils.

SOIL NET WT | 24 HRS. | 24 HRs. | 24 uRs. | 6 DAYS
DONC oe Se caiveak eaaeans 941.7 61.8 46.4 18.8 7.0
OAM vec.52edoavrsarnatacies 3 454 6 46.7 87.3 33.4 154.8
Sali: css seco Sue e eaves 497.4 770 46.0 410 144.5
CLAY! vies 05% soia oe oes wae 604 0 49.5 45.5 37.0 141.0
DOOS8t jc csics sess eaes ace 677.5 55.0 33.5 31.5 169 0
Humus................. 529.6 55.1 33.0 80.0 156.0

The evaporation from hard soil for each 24 hours is given
in the following table. There is also given in square cen-
timeters the amount of surface exposed to the air by each
dish of soil. The number at the head of each column is the
date of each daily evaporation.

WATER IN SOILS 15

Evaporation of Water from Hard Soils.

SOIL SURFACE & os afr Pr or
Sand....... 176.7 cm. 73 49 21 HA 0
Loam...... 167.4 ** 78 78 43 23 2
saline...... 179.1‘ 88 87 58 24 11
Clay ...... 167.7 “ 75 76 47 18 5
Loess ...... 167.4 “ 77 82 47 18 8
Humus. ...| 167.4 “ 80 vi 49 30 15

PE 23 26 27 os 25
Sand............. 0 0 0 0 0 0
LO am «ies cece 5 13 8 5 0 0
Saline. 3 21 16 8 3 0
CLAY esas power eee 3 14 6 6 2 0
Loess... ......0005 1 19 13 16 0 0
Humus...... 5 28 19 21 5 2

May 23 and 24 were cloudy days, the latter being very
humid, as a result of which the weight of the clay and loess
increased. When each soil became air dry it was heated in an
oven for 24 hours at 250° C. The sand when air dry contained
no measurable amount of water. The other soils coutained
water as follows: loam 4 grams, loess 7 grams, saline 3
grams, clay 6 grams, humus 5 grams. The sand lost its
water most rapidly; the humus retained moisture most
tenaciously.

From the foregoing data it is easily inferred that sandy
soils lose water by evaporation more rapidly than clay soils
and for this reason a plant must die more quickly in a sandy
soil than in one containing an excess of clay. Since the
plant is directly dependent upon the soil for its water sup-
ply, in times of drought the tenacity with which a soil holds
water is a matter of utmost importance in the economy of
the plant. The quality at once becomes of the greatest sig-
nificance in the consideration of the factors which control
the limit of water available for the use of the plant.

16 STUDIES IN THE VEGETATION OF THE STATE

Soils in nature always overlie strata of other kinds, and
the water contained in them tends to settle by gravity to the
stratum below. The rate of percolation depends upon the
capillarity of the soil, and upon the impeding action of the
hygroscopic water; probably upon even more obscure fact-
ors such as are involved in the varying chemical composi-
tion of the soil solutions.

According to Briggs* “The water contained in the soil in
regard to the manner in which it is retained may be consid-
ered to be of three kinds, gravitation water, capillary water
and hygroscopic water. Gravitation water is that portion
which is in excess of the amount which the soil is able to
retain under existing conditions, and is consequently free to
drain away. The capillary water is that part which would
be retained in the capillary spaces under these conditions,
and which is capable of movement through capillary action.
The hygroscopic water is that found on the surface of the
grains, which is not capable of movement through the action
of gravity or capillarity.

“The maximum amount of water which a given soil may
contain depends upon the resultant effect of two forces—
gravitation and surface tension. The force due to gravity
is proportional to the mass of the liquid considered and is
always directed vertically downward. In other words, it is
the weight of the liquid. This mass of liquid would there-
fore leave the soil if unopposed by the action of some other
force, the vertical component of which is acting along the
same line as the force of gravity but must be equal to it and
in opposite direction.”’

From this it may be readily deduced that in sandy soils
the amount of gravitation water is at a maximum, and capil-
lary water as well as hygroscopic water would be at a min-
imum. The clays, being the finest grained, hold the maxi-
mum amount of capillary and hygroscopic water, but here
the gravitation water would be ata minimum. The other
soils in quality vary between clay and sand.

*Briggs, Lyman J., Bull. 10, U. S. Dept. of Agr. Division of Soils, p.
6, 1897.

WATER IN SOILS 17

2. Physical Water in Soils.

The term physical water is used in this discussion to des-
ignate the water a soil may retain at any time. This is limited
only by the water capacity. The maximum amount of
physical water occurs in streams, lakes, etc. The minimum
amount is found in epiphytic or xerophytic situations. The
per cent of physical water in the soil is not a factor of abso-
lute value, since only the water available for the use of the
plant can be a stimulus to its growth.

A plant growing in saline soil requires a higher per cent
of physical water in order to live. This is illustrated by the
data gathered from plants growing on the salt-bottoms near
Lincoln. Helianthus annuus and Panicum crus-galli were
found dying in a saline soil with 14.9 per cent of physical
water present, while in loam they begin to die only when
the physical water drops to less than 10 per cent. Plants
can grow well in sandy soil with even less than 5 per cent
and in pure sand do not begin to die until the water content
falls below 2 per cent. The whole matter seems to hinge
upon the ability of the plant to take the capillary and hy-
groscopic water from the soil. This is dependent upon the
vigor of the plant as well as upon the density of the soil so-
lution. The imbibition of water by the roots of the plant
is greatly retarded in soils which contain chemicals detri-
mental to the assimilatory processes of the plant. The salt
marsh plants such as Atriplex argentea seem able to take in
a soil solution of greater salinity than is capable of absorp-
tion by ordinary plants. The leaves of Atriplex often con-
tain crystals of sodium chloride. May it not be that this is
formed asa bye-product and servesas a means of elimination
of the injurious substances in the soil? Atriplex grows
and thrives where a common ruderal plant would die from
the effect of the saline soil.

The welfare of the plant is dependent directly upon the
amount of nutriment if may obtain from the soil solution
and use in its economy. The soil solution may be so dilute
in hydrophytic situations that it is necessary for the plant

18 STUDIES IN THE VEGETATION OF THE STATE

to absorb a much larger amount of water in order to obtain
sufficient nutriment. On the other hand in times of drought
the soil solution may be too concentrated to be available for
the use of the plant. In alkaline and saline soils this takes
place with a much higher per cent of physical water present.

3. Physiological Water in Soils.

The term physiological water designates that portion of
the physical water available for the use of the plant. This
being the case it varies directly with the amount of physical
water on the one hand, and on the other it islimited only by
the plant’s ability to draw water from the soil. This is
varied by the physical factors which affect the vigor of the
plant. The plant prefers an optimum of heat, light, etc.
This optimum varies with different species. If a plant is
subjected to a stimulus which is greater or less than the op-
timum it must either adapt itself to the new condition by a
slight change in its protoplasm and later in its structure,
or, failing to adapt its structure, it becomes less vigorous.
in the latter case it can, in times of drought, draw less
water from the soil before it dies. Asaresult the amount
of physiological water in the soil is less in this case than in
the former. The different causes of the variation of the
limit of physiological water will be discussed more fully in
the chapter on that subject.

4. Non-dAvailable Water in Soiis.

The amount of non-available water in soils, as has been
indicated in the previous discussion, is varied widely by the
porosity and composition of the soil. Nearly all the water
in sand is available for the use of the plant, but the evapor-
ation and gravitation from soils of this nature is much more
rapid; as a consequence the amount which the plant can use
is much less than it may obtain from a soil containing clay
mixed with sand or loam. The finer particles of the clay
hold the water so tenaciously thatit is much longer in losing
its water content. In times of drought this gives the plant
in the clay soil a longer lease of life.

WATER IN SOILS 19

In an experiment with five species of plants growing in
six different soils, the plants were allowed to wilt excessively
under very dry conditions for two consecutive days. The
amount of water in each soil was determined at the time of
wilting and at the close of the second day of wilting. Tho
average of tbe results from five species is as follows:

Water in Wilting Plants and in the Soils.

SOIL PLANT
SOIL WATER WATER
% %

DAD Oe 52.4 case eannaneanie wind sat esites wabeoae 0 43 72.6
TOBIN «cia ois. cn dulnganenar es sedis waeely Gr lke: 11.00 16.9
Saline ce, awuy vrgoncwgmartareieke a aoe S44 14.00 81.5
Clay sak, Seesaciave« wewwkodsarszeaieeen 8.50 yar
LOGS8 jesse ccetack tice sewins dean oe eeuns 9 70 80.6
OMS, os a4.4 5 atveievansasenecns OL AEA AG AS. LSP eas 11.20 74.5

The plants used were Helianthus annuus, a cultivated va-
riety, Hordeum vulgare, Phaseolus vulgaris, Ricinus communis,
and Zea mays. Although the limit of non -available water
was not quite reached by these plants, the amount of water
that they were getting was below the amount requisite for
growth. If we arrange the soils in order of the per cents of
water they contained at the time of wilting the series is as
follows: saline, humus, loam, loess, clay, and sand, the
last being the lowest.

The following table gives the average amount of physio-
logical water used by the plants, and evaporated from the
soil during the period of drought, and the corresponding
loss of water frora the tissues of the plant:

Water Loss in Plants and Sotl during Drought.

s L F PLANT
SOIL LOSS OF SOIL OSS 0. N

WATER % WATER %
10.2 17.1
14.4 13.4
10.6 7.2
10.0 11.7

9.0 87
17.2 14.6

20 STUDIES IN THE VEGETATION OF THE STATE

It seems almost impossible to determine when plants are
wilting in the same degre, that is, when they have lost an
equal per cent of water from their weight. Until there is
some accurate way of determining this, the results obtained
are mere approximations. The whole subject of plant water
isa very complicated one since the water content of the
plant is varied by so many factors.

The amount of water in the soil non-available for plants
in time of drought appears to be affected by the same physi-
cal conditions that tend to vary the amount of water in the
plant, with the exception that in the soil the variation is
more uniform. The tenacity with which the protoplasm of
the plant may retain water probably varies not only in spe-
cies but also inindividuals depending primarily upon devices
protective against evaporation, and secondarily upon the
vigor of the plant. In times of drought, if the process of
evaporation be a slow one, the amount of water is increased
since the plant has a longer time to adapt itself to the
changed condition. On the other hand, a rapid evaporation
hastens the death of the plant and tends to raise the limit.
The physical factors which increase evaporation are in-
creased heat and light, decreased humidity, and winds. The
amount of non-available water is increased by shade, humid
conditions and abundant physical water. The effect of shade
upon plant structures is quite noticeable. Down to acertain
point of light diminution the size of the leaves is increased,
but beyond this point the effect is to decrease the size; at
the same time the root system is retarded in its development.

As a result shade conditions affect directly the ability of
the plant to exist in times of drought, and directly increase
the amount of non-available water. Humid conditions also
tend to increase the size of the leaves and at the same time
to retard the development of the root system, the effect be-
ing almost identical with that of shade.

WATER CONTENT OF PLANT AND SOIL 21

I. THE RELATIVE AMOUNT OF WATER IN THE
PLANT AND IN THE SOIL.

1. The Amount of Water in Healthy Plants and in the Soil
in Which They Grow.

Most plants contain a relatively high per cent of water in
their tissues. Hydrophytes,. as a rule, are the most watery
and xerophytes the least so; yet in the latter case there are
exceptions among succulents. Mesophytes, as other plants,
vary in water content according to the per cent of woodiness
or of succulency. Seedlings contain a higher per cent than
plants nearer to maturity. The per cent of water usually
decreases gradually until maturity is reached, then rapidly
to the minimum of the death point.

There are several physical conditions, which may affect
the water-retaining power of the plant. Among these are
varying humidity and soil moisture, excessive or deficient
light, poor food supply, injurious chemicals in the soil, and
injurious gases in the air or soil. Varying soil composition
does not seem to affect the water content of the plant unless
it causes a lack of food or water, or unless there are present
substances which act as poisons to protoplasm.

The following table gives the per cent of water in seedling
plants and in the soil at the same time. The plants were
three weeks old and were under the most favorable condi-
tions in the plant-house during the month of May. The
amount of light received by these plants was considerably
less than that received by plants under natural conditions.
(For record of physical factors see Comparative rlot III.)

22 STUDIES IN THE VEGETATION OF THE STATE

The Water Content of Seedlings.

SOIL PLANT
PLANT Som WATER, % | WATER, %
1S ca acearamaanens Sand 83 90.4
Phaseolus vulgaris eat Oe oni
Saline 299 90.0
Clay 169 89.5
Loess 12.4 89 6
Humus 19.0 90.0
‘i HWUS, oo ccecceveeee Sand 12.9 94.7
Helianthus an:iw osu ang os
Saline 20.5 93 6
Clay 164 87.6
Loess 199 93.9
Humus 29.1 90.2
um v POs eck eevee ede a 5% Sand 119 89.2
ates ve Loam 291 91.3
Saline 295 88.4
Clay 18.2 93 6
Loess 18.7 86.4
Humus 28 9 85.7
AVETAGES.. 66. eee eee eee Sand 11.0 91.4
Loam 261 91 2
Saline 26 6 90.6
Clay 17.3 90 1
Loess 17.0 90.0
Humus 25.6 89.6

In obtaining the data in the preceding table, it was noted
that Phaseolus and Helianthus plants were more uniform
in size and vigor than those of Hordeum. The following
table gives the per cent. of water in seedlings at the age of
five weeks, plants of the same species being used, and the
experiment being conducted in the plant cases. The fol-
lowing is the record of physical factors:

Physical Record Averages.

CASE TEMPERATURE | RELATIVE MAXIMUM SOIL

AIR, SOIL HUMIDITY LIGHT MOISTURE
| eT ee eee 61° 58° 64% 110% 18.1%
Tuvceinenaiowes ts 74° 66° 72% 0.5% 145%
Tis, sauce eae 76° 70° 55% 12.0 14.7%

LV acinaoswiunias ds "7° «71° 77% 12.0 16.4%

WATER CONTENT OF PLANT AND SOIL 23

Water in Plants, (in Per Cent of Weight.)
1. Phaseolus vulgaris.

LOESS LOAM SAND
one Water in Water in Water in
Soil, Plant | Soil, Plant | Soil, Plant
Dog beh Rhea cieieatcten nie Ae OA hs Ln, stele 15.5 78.7 17.1 84.7 1.1 80.4
TY sgh daactna sereadens owls Sa diate a ceas 14.4 92.4 18.7 95.4 0.7 897
DT se ieaseicie- Sarees a seaila nase seen heed 11.9 904 17.7 92.0 0.6 81.7
LV op cweinexegna Gangs Se. £5 a6u Rees 186 90.3 21.8 91.0 1.3 85.2
17.1 79.5? | 1.1 85.27
18.7 932 0.7 91.8
17.7 94.8 06 925
21.8 924 1.8 889
3. Hordeum vulgare.
Lp capices eine wal eee kaso e es 15.5 80.0 17.1 83.0 1.1 81.5
Lie ssansedti®, cies gareaauescen? 14.4 .... is7... hs rere
WUE suid do yetracavlucca weaabnansaielnd ofa 11.9 88.8 17.7 908 06 875
UME Lh a Soh cea olsls tala uhance Ashi, 18.6 861 21.8 864 1.8 88.1
Averages.
De eagei Awe ad KAY BRR shee Eee 15.5 76.3 17.1 82.4 1.1 857
Le see gesc ecu commana Sawer e4 14.4 928 18.7 943 07 907
MLD oS dnd dastrodit dens tegihaguviemuiene os 11.9 89.0 17.7 92.5 0.7 87.2
DV ior Ae it ap seca gaurd 2 2A 18.6 89.6 21.6 90.2 1.3 87.4

Totals of all Cases.

15.1 86.7 | 18.8 89.8 | 0.9 87.7

In the preceding table, the plants in Case I had been slight-
ly injured by cold a few days before the determination was
made. The plants in sand in two of the cases apparently
did not have sufficient water for full turgidity.

Seedlings of the same species have approximately an
equal per cent. of water. The most healthy and most vig-
orously growing seedling may not have the highest per cent
of water; in fact the reverse is usually true. The effects of
different soils upon the water content of plants is not very
marked in the case of seedlings. The effect upon older plants

24 STUDIES IN THE VEGETATION OF THE STATE

may be greater. Turgid plants growing in sand have the
highest per cent. of water. This must be due to the lack
of nutrient salts in quartz sand. The plants in this soil
grew the slowest and were the least vigorous in appearance.
Those growing in humus were by far the most vigorous in
size and appearance, yet had the lowest per cent of water.
The series of soils taken in order of plant vigor from the
highest to the lowest is as follows: humus, loess, clay,
saline, loam, sand. The fact that parasitic fungi attacked
the roots of the plants to a greater extent in some soils than
in others slightly vitiates the results obtained. The plants
of Zea in Case II were attacked by Fusarium but the results
from the diseased plants were not included in the table.
One thing is strongly indicated, namely, that the plant which
is most vigorous does not necessarily contain the most water.
In fact, the least vigorous plants were the most watery, for
example, those growing in the shade in Case II.

2. The Amount of Water in Plants Wilting Strongly under
Measured Physical Conditions, and the Corresponding Amount in
the Soil.

The cause of the wilting or drooping of the aerial portions
of the plant is the lack of cell turgidity due to a loss of
water. When the protuplasm loses water, it ceases to exert
a pressure upon the cell-walls and gradually shrinks in bulk
allowing the whole superstructure of the softer portions of
the plant to collapse. Any physical factor that increases
the evaporation from the leaves to such an extent that the
roots cannot furnish a compensatory supply is certain to
bring about this condition. Plants growing in natural con-
ditions often wilt considerably during the hotter and dryer
portion of the day and recover their turgidity during the
cooler and moister hours of the night. Most plants seem
able to withstand a succession of such experiences without
serious injury if timely rains intervene.

Although many observations were made upon the relative
amount of water in wilting plants and in the soils in which
they grow, but one experiment was conducted with this end

WATER CONTENT OF PLANT AND SOIL 25

in view. This was carried on with the plants in Compara-
tive Plot III. The following data were obtained from five
species of plants growing in six kinds of soil.

Water Content of Healthy and Wilting Plants, and Water in
Soil at the Time of Wilting.

Helianthus annuus.

Physical Condition at the Time of Wilting.'

Air-teM Peralurers siete cvsaweradensedviewae GurgdowewAaadcsawes Yee 90°
Relative humidity ...15 seesaverrsesceeeuewneda vets cage vee caneeetans 44%
Soil temperaturers ...ccteneeasees tira nia whee Gagretecssin raed seas 104°
Maximum Jig bts so. kage shew ale PE eed d aise Duis Fhe Hated gehenOe ee 35%
Saiz. WATER IN SOIL, | IN WILTING IN TURGID
% PLANT, % PLANT, %
0.4 78.8 94.7
11.6 87.6 92.2
15.1 85.4 93.6
9.1 84.9 87.6
10.9 81.5 93.9
11.5 79.2 90.2

Hordeum vulgare.

Physical Conditions at the Time of Wilting.

Air temiperature: «sce ec eaeedes ev aees at eae te eae ae dals 100°
Relative Wun bys co: Ga. 's Sascepienis aneee “a oes evlocgpemoaeanld Oe eae Fo aGuee 47%
Soil, tem POratUre’ : 2 v.a22%. wee edetnctnaracstaleca Grenada cacayeualaanere Gusielo-acb-a areca paleies 106°
Maximum light...............-0005. nih ntosbce avi tiontatea a de avg dh echosam nd means 35°
WATER IN SOIL,| IN WILTING IN TURGID
5OnL % PLANT, % PLANT, %
0.4 70.0 89 2
9.8 52.0 91.3
9.8 82.2 88.4
6.4 69 8 93.3
8.1 79.4 86.4
11.3 69.1 88.8

26 STUDIES IN THE VEGETATION OF THE STATE

Phaseolus vulgaris.
Physical Conditions at the Time of Wilting.

Air temperature........ 0. cece ee cence ee cee eet ete ene ents 100°
Relative humidity..i0sa ccecseesceee dase esa quae ae pees eeu e ew ee 48%
Soil temperature........ cece cece eee ee teeter ees 104°
Maximum light........ cee cece seen ence e teen eet e eee e senate eaees 35%
s0Kd. WATER IN SOIL, | IN WILTING IN TURG1D
% PLANT, % PLANT, %
04 78 0 90.4
10.6 80.5 90.1
17.2 80.0 90 0
8.5 78.9 89 5
8.4 85 6 89 6
9.3 81.0 90.0

Ricinus communis.

Physical Conditions at the Time of Wilting.

Air temperaturcisssingcackiee MuserieeerecenedEs teas Kauaa ee es 100°
Relative huMidityssscsscwssewkoseeeeriy Kees raed oar deme wnasee Pees 46%
Soil temperature: «20s caren dead veivaid ees weds et sades eee eeNeNES 106°
Maxnnum light....0.. ssigoccamsegae deus wens seess paness ; ema Y .. 85%
— WATER IN SOIL.| IN WILTING IN TURGID
% PLANT, % PLANT, %

05 63 2 84.4
103 82.5 84.4
12.0 76.5 84.4
92 80 6 84.4
78 743 84.4
12.1 79.7 84.4
Zea mays.
Physical Conditions at the Time of Wilting.
Ain Cem peratures se. cistanh Aeewiatewee vey e a4 58d ad Gaewuniuageoule ees 100°
Relative: MUMIGty: saccades salavcuee senso See wtcns anos Sgeaned warren ve 47%
Soil temiperaturen vec ic ccsucpaaasas tae Gess cad aeutauenweramancnns 106°

Maximunt light: sacucu.osniaienisasen ds mata Rereeaeaaeen hos 35%

WATER CONTENT OF PLANT AND SOIL 27

son: WATER IN SOIL,| IN WILTING IN TURGID

% PLANT, % PLANT, %
Sand wncd sidceangaas 0.4 72.2 92.0
08M... cas weniadsagwls sys 12.5 81.7 92.0
Salin@s 2s s2scasies vewss a 16.8 83.4 93.0
Clay ces. ceases ees 9.4 75.0 92.0
LOSS) 33-024.c4 windeay oes 131 82.4 92.5
Humus........... ects 11.0 83 5 92.0

Average of Results.
Physical Conditions at the Time of Wilting.

Alf CEMpPCratunescisic cae cra rowel ote aad HeshewMe wa TEES eens 98°
Relative. HUM iaete ir gsc00 Pe reoeeeae es eee pase der wee eyeed SEA 47%
Oil Lemiperatune las cack Rae: ee eee sie eeaids uadeamhaes seeee es 105°
Maximum lightens svyeees: «sing as Wap oles eae cua eGadnaweNs eee eer Oat 35%

(Number of plants, 60.)

sori, WATER IN SOIL, | IN WILTING IN TURGID

% PLANT, % PLANT, %
Sano wae ae oben 0.43 72 6 90.2
LOAM 6554 cseaisdcutarg tanec 11.0 76.9 90.0
Saline’ 6 s4%¢ 444 5 emiewen 14.2 81.5 89.7
Clayiccdvesceciaad gpa 8.5 777 89.4
LO@SSi.4 sos cha ee sauna 9.7 80 6 89 3
FAUMUS 3 see econ aauee 11.2 74.5 89 1

If from these data the soils are arranged according to the
amount of water they contained at the time the plants were
wilting, they make the following series from the highest to
the lowest per cent: saline, humus, loam, loess, clay,
sand.

The following table indicates the average time the plants
in each soil were subjected to drought, the average per cent
of water lost from each soil, and the average per cent of
water lost from the plants if based on the amount found in
turgid plants.

28 STUDIES IN THE VEGETATION OF THE STATE

Per Cent of Water Loss un Plants and Soils,

TIME IN WATER Loss | WATER LOSS
cor DRYING OUT. OF SOIL. OF PLANT.
6.0 days 10.2 W711
6.2 14.4 138 4
6.8 10.6 2
6.0 10.0 det
5.2 9.0 8.7
6.0 17.2 14.6
6.0 11.9 121

The table above is not accurate as to the time of drying
out given for sand, or as to its water loss, because the plants
in sand were watered in order to keep them alive until! they
would die under the same temperature conditions as those
in the other soils.

The great difference which these results show in the com-
parative amounts of water in the soil and in the plant at the
time of wilting call for an explanation which at the best
must be more or less theoretical. We may assume that the
difference of 8 per cent. between the sand and the clay is due
solely to a difference in capillarity and surface tension, and
to the presence of a greater amount of hygroscopic water in
the clay. This explanation may account for the greater
portion of the difference between clay and sand. It will not
however explain why the plant wilts at a higher per cent.
of soit water in loam, humus and saline soils.

The sand used was quartz sand and contained only
a trace of soluble salts. On the other hand, the saline
soil had the highest per cent. of soluble matter. May
it not be possible that the concentration of these salts
as the soil gradually loses water is a factor that plays a very
important part in checking the interchange which takes
place between the solutions in the protoplasm of the root
hairs, and the soil solution? There is no doubt that the in-
creasing capillarity and hygroscopicity of the finer soils
impedes this important process, either causing it to cease,
or bringing about an actual transfer of solutions from the
protoplasm of the plant to the soil solution. In the case of

WATER CONTENT OF PLANT AND SOIL 29

saline and alkaline soils, the root hairs, being strongly acid in
their nature, must suffer from the increasing alkalinity of
the soil. This isa fertile field for investigation and it is
hoped that these problems will soon be taken up and solved
by the plant physiologist.

In mesophytes when wilting, the amount of water lost by
the soil nearly equals the amount lost by the plant. It might
be inferred that a plant ceases entirely to take water from
the soil the moment wilting begins, and from this time on
it simply undergoes evaporation. However, it can hardly
be true that the plant ceases entirely to take water from
the soil until it has lost much from its own weight. The
facts in the matter may be obtained by a simple epxeriment.
If several plants be taken atthe time when they begin to
lose turgidity and part of them uprooted, and their roots care-
fully sealed with wax or cocoa butter, these should lose
water more rapidly, if it be true that plants in the soil do
not cease to absorb water when they begin to wilt. Both
should lose weight equally if the plants in the soil are not
obtaining water, and finally, if the sealed plants should lose
water more slowly than those in the soil it would be positive
proof that the soil is actually taking water from the proto-
plasm of the roots.

The plant absorbs very little water from the soil after
it is wilting excessively. From the very nature of the root
hairs, it is quite certain that they perish soon after the
plant begins to suffer from drought. This is indicated by
observations to the effeet that the roots of many annuals die
before the stem and that they commence to lose water about
the time the leaves die. Should it be found out later that
this is certainly the case, the effect will be to increase the
estimates of the limit of the non-available water and conse-
quently to diminish those of the available water. This being
the case the tables at the close of this treatise will need
revising, but the general results and conclusions of the work
will remain unchanged.

30 STUDIES IN EHE VEGETATION OF THE STATE

3. Observations upon the Water Content of Plants Dying from
Drought and the Corresponding Water Content of the Soil.

The relative amount of water in plants dying from drought
is usually varied by the same causes that vary the amount
of water in the healthy plant. This varies with the natural
woodiness or succulency of the plant and is greatly modified
by the physical conditions under which the plant develops.
The discussion of the wilting plant in the previous chapter
might be made to include the dying plant, for there can be
no definite line of demarcation between the two conditions.
The wilting is but the beginning of disturbances of function
in the plant which if continued result in its death. Owing
to the difficulty of examining the roots of the plant at every
stage of the process of wilting and dying, it is almost impos-
sible to tell when a plant ceases to obtain water from the
soil, and actually begins to die. So long as this is the case
there will be an uncertainty about the results obtained in
estimating non-available soil water. The plant must cer-
tainly live for some time after it ceases to take water from
the soil. The length of this period depends directly upon
the store of water in the plant and its ability to hoard it.
The ordinary mesophyte seems to be deficient in both re-
gards, yet in a number of species studied, such plants lived
even after the roots had died, that is, until the soil appar-
ently aided the roots in extracting water from the resistant
living cells of the stems. This happened usually under
conditions where the evaporation of water took place very
slowly, and the death of the plant was prolonged.

Grasses when turgid contain a lower per cent of water
than many other herbaceous plants, and when dying they
show a still greater proportionate difference. It was impos-
sible to experiment along all lines, and the data given here
are from observations made at various times in connection
with the other lines of experimentation. A grass containing
15 per cent of water or less is dead almost beyond a doubt;
with from 15 to 20 per cent its condition is uncertain and it
is doubtful if it could be revived; above 20 per cent, life
usually remains in most grasses. A_ succulent plant

WATER CONTENT OF PLANT AND SOIL 31

apparently dies with a much higher per cent of water than
a woody one, although its death usually takes place more
slowly. The roots of Coleus and Nasturtium die before the
stems, but after the root is dead and dry the plants will not
recover although there may be 50 per cent of water remain-
ing in the stems. Lobelia syphilitica usually begins dying at
50 to 70 per cent and is usually dead at 40 per cent.

The following results indicate the difference between some
rosette plants of hydrophytic tendencies in the amount of
water in the soil and plant when the plant is dying, and the

amount in rosettes of xerophytic tendencies. The plants
were grown in loam in the plant house.

Lobelia syphilitica.

PHYSIOLOGICAL |NON-AVAILABLE WATER IN

PHYSICAL CONDITIONS

WATER IN SOIL,

%

WATER IN SOIL,

DYING PLANT,
0

In Sun, Wet Soil........ 15-30 11.4 57.9
In Shade, Wet Soil .. ... 15-30 11.5 44.1
In Sun, Dry Soil ....... 8-15 1038 52.0
In Shade, Dry Soil..... 8-15 Wy 68.1

Average with Six Species of Xerophytic Tendencies.

In Sun, Wet Soil........ 15-30 8.6 39.0
In Shade, Wet Soil...... 15-30 6.1 33 8
In Sun, Dry Soil ... ... 8-15 6.9 314
In Shade, Dry Soil...... 8-15 66 39 0

From this and similar results obtained, it was found
that hydrophytism tends to make a plant more sensitive to
excessive water loss, so much so that it dies with a greater
per cent of water in its tissues than in the soil. The hy-
drophytic plant usually has more water in its tissues when
turgid and itis to be expected that it might die witha
slightly greater relative per cent of water, both in the plant
and in the soil. Other variations of the water in dying
plants will be discussed under the next section. The fol-
lowing tables give resuJts from three species, one of xerophy-
tic tendencies, one of hydrophytic tendencies, and a meso-
phytic grass, all grown in loam in the plant house.

82 STUDIES IN THE VEGETATION OF THE STATE

Variable Water Content in Plants and Soil.
Atriplex argentea (stem stage).
(xerophytic. )

PHYSIOLOGICAL | NON-AVAILABLE WATER IN

TIME IN DYING WATER IN SOIL, | WATER IN SOIL, | DYING PLANT,
%o fo %o
B4.Day gsc cca vas 6554558 13.2 4.1 26 1 dead
13 Days............... 10.4 4.2 27.1 dead
11 Days... scccceccevves 10.0 8.9 35.6 dying

Eclipta alba (flowering stage. )
(hydrophytic. )

LC DAYS en. 25 cow eaaes 2.6 6.5 37.0 dead
8 Days............66- 15 0 7.6 43.0 deaa
DD DAY ores cctreeearerainaw 20.0 V4 50 0 dying
1 0 Bf ae ne ee 15.0 88 50.8 dying

Elymus canadensis (bunches. )
(mesophy tic. )
15.5 4.8 15.2 dead
15.0 5.1 21.6 dying
10.0 5.8 23 8 dead
2.0 5.6 26.5 dying

The data given in the preceding table were obtained from
plants thought to be dying, the determination being made
at a time when all the plant’s aerial organs appeared to be
either dying or dead. The per cent of water ina dying
plant as well as in a living growing plant varied with the
vegetative stage and ageof the plant, depending on whether
it is a seedling, a rosette, a stem, or a fruiting plant. The
first in the series has the highest and the last the lowest
per cent of water. Again the amount of water in a dying
plant may depend upon the variation of the nature of the
tissues in different species, ranging from succulents with the
greatest per cent of water in their tissues to woody plants
containing the least.

The following table indicates the effect of different physi-
cal stimuli during the lifetime of the plant upon the relative

WATER CONTENT OF PLANT AND SOIL 33

per cent of water in the plant at the time of dying. They
are taken from Comparative Plot II (See record of average
physical factors for this plot). These are the averages
from 36 pots of Zea mays and Phaseolus vulgaris.

Effect of Physical Stimuli.
NON-AVAILABLE WATER IN DYING

WATER IN SOIL. PLANT.

Case I. (Reduced temperature).

LG MUO Y Bras ese Ses Soe sg aes isis mb sian dlecs wares 5.7 40.4

Phaseolus vulgaris.... ....... 0.2.0.5 5.9 46.1
Case II. (Intense shade).

LOG MAY Svcs 2auis seeded Seka aes 8.4 54.6

Phaseolus vulgaris. Wanapea Gee om eanaunar a hone 8.8 56.7
Casz 1II. (Low to normal humidity).

LCM NAY Ss ics sree Vee Cie saa a ait ese ws 8 4.5 48.0

Phaseolus vulgurts......... .....00.- 5.9 31.9*
Case IV. (High Se

ZOO MAYS. ws. Saeseden se x ese teas 5.6 53.3

Ph. seolus vulga 18 ......... 000000000 5.8 60.5

*Partly diseased

In determining the water in dying plants, great care was
taken to have the plants near the death point, and this being
the case the variations in the results from different condi-
tions may be ascribed partly to differences in plant vigor,
and partly toa change in the structure due to adaptation.
The intense shade in Case II. was without doubt the cause
of the high limit of soil water and the high per cent. of wa-
ter in the dying plants. The plants inthis case were greatly
elongated in length. They were etiolated and lacked in
fibro-vascular tissues. As soon as they were deprived of a
water supply in the soil, they collapsed. The results from
Case IV. indicate that high humidity has a tendency to pro-
duce the same effect on the limit as shade, but to a less de-
gree,

C. NON-AVAILABLE WATER IN SOILS; HOW VARIED.

1. Effect of Increased Heat (and Light).

In the consideration of the effects of heat, light must be in-
cluded, because it was inseparably connected with the high

34 STUDIES IN THE VEGETATION OF THE STAT

temperatures of the plant house during the last few days of
experimentation. Yet in summing up the results it can
hardly be claimed that the light in the plant house at any
time was too intense for the best development uf the plants.
The maximum amount of light was slightly over 40 per
cent of the standard of June 22. The temperature
however was high, the average maximum for the last twelve
days was 100° for the air, and 101° for the soi]. Plants dy-
ing under these conditions had a higher limit of physiologi-
cal water and of plant water than plants dying under cooler
conditions with less light. The following table gives the
results from Comparative Plot III. from plants grown in the
plant house during May, 1901, in loam, loess and sand.

Comparative Plot Il. (Increased heat and light).
Physical factors during the drought period.

Average maximum heat.........6. cess cee eee cece tee cee eens 100°
Average minimum humidity..............-.- adi yale caren aieaks uate’ 51%
Average maximum soil temperature..........-26. chee seen eee ee 101°
Average maximum light.......... 0... eee ee eee eee een ae 38%

Phaseolus vulgaris,

BOLE NON-AVAILABLE WATER IN
WATER. DYING PLANT.
TeO Bui fetes pales ccs ome ist anttnn es 8.7 53 0
OCSSi.meerersc.” se scaouns os wNeneos 8.7 53.8
Sand: capsewev eiyeeeseee ye Son aes 0.26 38.8
Helianthus annuus.
BQ AMT) 5. sce acaioceloneiaionecad GA aaa 11.2 61.4
TEGO SS tis weir act aheemarciatas & Geeseos bale esa ale 10.2 55.2
DADO ssaciie aceatainwGs Badr Gos ere we 0.2 449

Hordeum vulgare.

vag
ro)
D
wa
a
S © 9
wre
a
Ss
a

WATER CONTENT OF PLANT AND SOIL 35

Ricinus communis.

SOIL NON-AVAILABLE WATER IN

WATER DYING PLANT
0a oswanaice saves seca. aye aa es 9.1 61.0
Loessssexceawee eens. vite -vadsoaeate 109 49.6
BANG g ceneuyeasenco ue hk a niet Supenonehteane: 0 44 24.3

Zea mays.
TOs genoa ss) sean seen 10.1 10.4
OOSS neu ewatien Tyee dead ane ok 9.3 56.1
Sands) veccass org vere seek newer es 0.41 58 2
Average for Five Species.

Oa ssuiowadwateauta than. Macatee’ 96 61.0
LOSS ix siciaccrmioitcaisy seed eiad aa eee yaeG,% 9.6 528
Dan Gl eacacvan ineioren Po Neat ante rae lene 0.32 43 8

The plants named in the following tables were grown in
the plant house under a lower average temperature and less
intense light than those of the previous plot, and the re-
sults are given for comparison.

Comparative Plot Il.
Physical record while plants were dying.

Average maximum temperature....... 2...) eee cece eee teens 94°
Average minimum humidity.......... 0.0... e ccc ec eee eee ees 46 %
Average maximum soil temperature.... 2... ek cee eee ees 90. °.
Average maximum light....... 1... cece eee cece n nee cee nae 13.23%

Phaseolus vulgaris.

NON-AVAILABLE WATER IN
SOIL WATER IN SOIL, DYING PLANT
% fo
DOaMh cca 0 aeisccheaduseend ed een Sao 62 27.2
L088 oe. 50.3 adiscsinaicnwvnna.e a oeneage: ober 5.8 22.3
AN sies crnsatnlelietaee aera, seo ves 4ilaee 0.45 29.6

Helianthus annuus.

48
OCS 9 s.2 esc areviptevechtaae aki eteeees 7.8 49.2
; 0.78 31.8

36 STUDIES IN THE VEGETATION OF THE STATE

Hordeum sativum.

NON- AVAILABLE WATER IN
SOIL WATER IN SOIL, DYING PLANT

% %

OAT epg cias Silt he tel sae ne Lathes 3.5 43.7

LIOCRS races iehauatin'ny weer deals pares) ohm 2.6 23.5

DAD jelous, sk wes s SER eas 5 Ae UR 0.46 27.0

Ricinus communis

LOOM icles eect rdes os trbonekes omens 5.9 17.8

TRG OSB sates wees sh becielad & eeavalicareeaatinisdetinsis 6.4 291

DBI 3 ioccc eae cake oad Gee Mieamineaaengs 1.0 30 9

Zea mays

LoOd! ys ss aaeierte iodo nataedie ess oes 3.7 29.8

TOOBS is reed steers cies ib died hace sre acd ecdeans das 4.7 33.9

SaNdainswie accoueamweciaee «hen eae 06 49.8

Averages

TL0aih: 2 + ainswcrnin guesses ses bee seas cee 5.0 28.7

TiOOSS's: cickstsags ob 8 ths ch ee Ped Shades 53 29.6

ON! cscs cece Sanus: wid dasa peat dace 0.65 39.8

Average Increase in Plot LI.

LOG w.2 ese es d4 a4 pre eee 4.6 82.3

LeS8iis5 5 pe hab dekw es man koe ed 4.6 23.2

DANGs 4s coce (os chen OG deeaatiensneveas 0.3* 4.0

*Decrease,

Owing to the lower per cent. of water in the plants in Plot
IL., it is difficult to get accurate comparisons with those of
Plot III. and to make definite conclusions from the results.
If the non-available water in each case could have been de-
termined at the time when the plants of the same species
had approximately the same amount of water in their tiss-
ues, the comparisons might have been made with a greater
degree of accuracy. It certainly can be said that the com-
parison of the results indicate that temperatures even

WATER CONTENT OF PLANT AND SOIL 37

slightly above normal at the time of dying increase consid-
erably the amount of non-available water.

Obervations and determinations of water content were
conducted with plants of Syntherisma sanguinale in the plant
house during a period lasting from March 25 to May 3.
The results of these observations are separated into two
groups, 19 were made before April 5, and 19 afterward.
The results will now be compared.

Physical factors, March 25 to April 15,

Average air temperature.................

gaatent: atieaie gente lsersae 71°
Average relative humidity........ 000.0. cece cece cece e cece eens 67%
Average soil temperature.......... 0.0... cece cece eee cee 72°
Average maximum light......... 0.00 cece cece eee e eens 12.01%
Physical factors, April 15 to May 8.
Average air temperature... .. 0.6.6 eee cece eee ee cence eee eeee 76°
Average relaiive humidity.........0. 0.00. c cece ee eee e eee ee eens 66%
Average soil temperature... ......... 0.0 c eee cece cece eee eee 80°
Average maximum light ........... 0. cece eee eee eee eee 24.8%
Syntherisma sanguinale.
PLANT
LIMIT ek
Average of 19 plants, Mar. 25 to Apr. 15..... 6.1 40.1
Average of 19 plants, Apr. 15 to May 3....... 5.1 40.1

In the same way the observations on Chaetochloa viridis
are separated into two groups, eight taken before April
14, and eight after April 14, the physical factors being quite
the same as before.

Chaetochioa viridis.

PLANT
LIMIT aR

Average of 8 plants, Apr. 3 to Apr. 14........ 7.0 38.8

Average of 8 plants, Apr. 14 to Apr. 30....... 6.1 25.7

38 STUDIES IN THE VEGETATION OF THE STATE

It may be well to give the results from two other grasses
in addition to the previous ones, the physical conditions be-
ing similar.

Panicum crus-galli.

PLANT
LIMIT Set
Average of 5 plants, Apr. 5 to Apr. 17........ 6.6 29.3
Average of 5 plants, Apr. 17 to Apr. 29...... 6.2 33.1
Chaetochloa glauca.
Average of 6 plants, Mar. 9to Apr. 1........ 7.5 29.8
Average of 6 plants, Apr. 1 to Apr. 29........ 71 26.2

The results from these grasses indicate that the increase
of light and heat was favorable to the plants, mcreasing
their ability to take water from the soil. The winte condi-
tions of the plant house were shade conditions, and as the
light increased the plants became more and more vigorous;
the heat increased at a more rapid ratio than the light, but
in case of the grasses did not become excessive while the
plants were dying, the physical conditions being similar to
those of Comparative plot IT.

EFFECT OF TEMPERATURE BELOW THE NORMAL.

Since the normal or optimum temperature may vary with
the habitat of the plant, the results obtained by growing
plants of different habitat under a certain range of temper-
ature fluctuations are apt to vary with different plants. Case
Icontained plants of three species, viz.,Zea mays, Phaseolus
vulgaris, and Hordeum vulgare, grown in loam, loess and sand,
at a temperature usually varying from 5° to 20° below that of
the other cases. The following results from Case I and
Case ITI, will show the effects of a slightly lowered temper-
ature as compared with those of the normal in raising or
lowering the limit of physiological water. The averages are
taken from thirty plants in each case.

WATER CONTENT OF PLANT AND SOIL 39

PHYSICAL FACTORS CASE I CASE III
Average temperature ......... 0. cece cece ees 610 76°
Average humidity..... 2.0 22. ...... eee. 64% 55%
Average soil temperature. ................06. 58° 70°
Average soil moisture........0. 0... eee eee eee 151% 14.7%
Average maximum light.................... 11.0% 12.0%
Results.

Average limit of physiclogical water......... 54% 4.8%
Average water of dying plants. .. .......... 34.7% 30.4%

The colder air retarded somewhat the growth of plants in
Case I, and its effect was to increase the average of non-
available water to the extent of 0.6 per cent. The plants in
Case I were longer in dying than those in Case III because
in the lower temperature the evaporation took place more
slowly. The average time of dying in Case I was 19 days,
in Case III 25 days. The slower evaporation of water tended
to allow the plant more time for adaptation, lowering the
physiological water limit and counteracting the effect of the
cooler temperature. This being taken into consideration the
difference in the average from the two plants would be the
more significant if it were not so small. The difference
caused by the cold was not noticeable in the case of barley and
oats, but was quite striking in the case of corn and beans.
This bears out observations of farmers to the effect that the
small grains grow well during a cool spring, but corn is re-
tarded.

3. Effect of Increased or Decreased Humidity, when excessive.

The plants grown under the conditions of case IV, were
constantly in a humid air, even when the soil was deprived of
water in the determination of the physiological water. They
grew taller than those in the other cases. The leaves were
slightly larger, and the root system less extended than those
of the plants in the Cases I and III where the air was less
humid. Comparing the results with those from Case III,
the case with the normal conditions, the effect of the in-
creased humidity is readily seen.

40 STUDIES IN THE VEGETATION OF THE STATE

PHYSICAL FACTORS CASE IV CASE III
Average temperature.................0 eee eee v7 76°
Avernge humidity... 2.0.0.0... ccc cece eee eee 71% 55%
Average soil temperature 71° 70°
Average soil moisture... ..............00055 16 4% 14.7%
Average maximum light................ ais 120 12.0

Results sass wag were es cee eouloe, solace des

Average limit of physiological water........ 6.4 48
Average water in dying plants............... 47.2 30.4

From this experiment it is proven that humid air tends to
increase the size of the leaves, and to diminish the root sys-
tem of the plant. The plant begins to adapt itself tu living
in such conditions, but in such a way that when the soil
dries out even with the air humidity unchanged, it is unable
to draw as much water from the soil as a plant growing
and dying in less humid atmosphere. The difference in non-
availabe water, 1.8 per cent., is quite marked.

The effect of suddenly transferring plants raised in a
moist atmosphere to a dry one was shown by taking two col-
lections of potted plants raised in the plant house and trans-
ferring one of them to the xerophytic conditions of a dry
laboratory, leaving the other in nearly similar conditions of
light and heat in the more moist plant house. The follow-
ing data show the effect of true xerophytic conditions on
plants raised in a more humid atmosphere.

Comparative Physical Record of Plant House and Laboratory.

Average air temperature, planthouse......... ...... 00.0.0... cae 71°
Average air temperature, laboratory..............0.cccccc cece aces 72°
Average relative humidity, planthouse.....................0.-0000. 62%
Average relative humidity, laboratory. ..........0..00..0. ccc eee 38%
Average soil temperature, planthouse...............0....-006 cee ee 68°
Average soil temperature, laboratory..........0....000.0 cececeeeee 67°
Average maximum light, planthouse..................0..0c0cceeee 10.5%

Average maximum light, laboratory........... 0.0.0. c ccc cecec cece 20.5%

LIMIT OF PHYSIOLOGICAL WATER 41
PLANTHOUSE. LABORATORY.
© 3 Oo) 8
2 e || 3 E
a a | s a
8 a bo a pS
sa | §2 3 | §2
SE | 34 se | aS
Z = z =
Ambrosia artemisiifolia.............. 3.4 27.8 12.4 65.7
Ambrosia artemisiifolia.............. 03 24.4 0.3 15.0
Atriplex argentea..............0..6. 4.1 26.0 7.3 200
Atriplex argentea................04. 4.3 27.1 8.9 35 6
Cassia marilandica ................. 4.4 18.0 7.0 55.4
Chaetochloa viridis....... .......... 46 18.8 5.1 13.8
Chaetochloa Viridis.................. 5.2 21.9 5.6 15.4
Elymus canadensis... ............-. 53 18.6 5.8 23 8
Elymus canadensis........ ........- 5.6 26.5 72 23.7
Euphorbia marginata............... 4.3 50.9 6.7 46.1
Grindelia squarrosa.............0085 6.8 45.9 8.8 44.2
Gaura parviflora............. cece eee 4.8 29.9 6.5 13.0
Helianthus annuus.................. 7.8 33.8 5.5 18.2
Helianthus annuus... ............. 7.5 19.8 8.2 27.9
Hordeum jubatum,................. 5.8 22.0 67 28.7
Hordeum jubatum............... .. 5.3 42.2 3.6 12.4
Lob lia syphilitica........00 ....... 8.3 42.6 100 40.2
Leptilum canadense ...............- 6.1 17.1 9.7 14.3
Nasturtium officinalis............... 3.4 62.5 4.3 19.4
Oxalis strictas sjeeewia casing ep cans 4.8 11.1 6.5 13.0
Oxalis strictansscecesvveie seas a aarces 7.9 17.4 8.8 22.2
Panicum crus-galli...............0- 6 2 31.6 6.8 25.0
Panicum crus-galli,. ...........-08. 5.5 25.2 6.8 25.2
PB. prolifera: o.c.60s ec occas sees 9.7 42.9 6.9 37.6
P. virgatum.........-0ccccneee eee 10.0 505 13.6 42.7
Py WaltOllciae ens cu raed aeons sie 6.5 25.4 7.5 33.7
Plantago purshii.................66- 5.8 22.2 8.8 16.1
By, TUES ioe sles gieccies he genders eda 4.5 34.7 6.2 37.6
Sporobolus vaginiflorus...... ...... 34 13.0 4.1 16.3
Syntherisma sanguinalis............ 6.6 37.3 7.3 27.7
Gaura biennis................ eee eee 5.9 28.3 5.4 13.7
Chaetochloa glauca.............008- 76 35.5 7.2 16.7
Sonchus arvensis.............0 eee eee 5.1 27.8 7.7 33 2
Verbena hastata.............0. eee 34 17.2 6.0 12.5
Verbena hastata............. ee ee, 0.3 26.7 0.3 10.5
Verbena urticifolia...............06 6.5 12.5 5.7 39.0
Average, 27 species...............4 5.4 28.6 6.8 27.2

42 STUDIES IN THE VEGETATION OF THE STATE

When a plant is suddenly transferred from moist condi-
tions to xerophytic, the rapid change prevents the plant from
adapting itself at all to its conditions, and death takes place
quickly. This was especially true of the two plots for which
data are just given. The plants in the laboratory were all
dead by the time the first in the plant house began to die,
the average time of drying up was twice as long for the plant
house. The difference in the averages is quite pronounced.
The plants transferred to the xerophytic laboratory died at
an increase of 1.4 per cent in the limit. This indicates
that periods of drought following quickly after moist weather
and good growing conditions may injure plants more
quickly in the fields than a more gradual change from wet
to dry weather.

4. The Effect of Increased or Decreased Soil Moisture during
the Growing Period.

If a xerophyte is placed under the conditions of a meso-
phyte, or if the latter is placed under semi-hydrophytic con-
ditions, in either case the plant must adapt itself to the new
conditions or become unhealthy and die. Such a plant can
rarely fully adapt itself in one generation but manages to
exist and reproduce itself though in a condition of lowered
vitality. The same thing is true where the order is reversed
and the hydrophyte and mesophyte are put under the effect
of a lower per cent of soil moisture than that to which they
are accustomed. :

The following data were taken from plants growing in the
plant house in the same physical conditions, with the
exception of a difference in the water content of the soil.
The results indicate the effect of increasing the water in
the soil beyond the amount to which the plant has been
accustomed. Most of these plants are mesophytes but
several have xerophytic tendencies. The latter show the
greatest differences.

LIMIT OF PHYSIOLOGICAL WATER 43

NORMAL SOIL EXCESSIVE SOIL
zs WATER. WATER.

ice a 7 _ 2] oe 33
8H |sH| 2 || Sala] &
ws {Sal o™ ll ma] Sa]

wa | Soe w= | ioe |
Lu] Ea lt ol] Sal Se [7 ww
2Blaxlua SSlasled
ge | 22 (28 | 22] 28/24

6) ro)

a le te a le
Acnida tamariscina. ............... 14.0 | 8.6 | 44.4 || 20.0 | 182] 48.6
Ambrosia artemisiifolia............. 102) 5.2 |174 || 16.0 | 33.7 | 32.5
Aster cordifolius. .................. 5.0 | 6.9 | 328 || 15.0] 7.2] 85.6
Gaura parviflora ................... 5.1, 7.4 | 37.5 || 150, 9.8) 30.6
Gaura parviflora ............. ..0.. 6.6 | 5.2 | 19.2 || 15.0] 9.1 | 46.8
Gaura biennis..................000. 84] 7.8 | 52.5 |} 15.0] 9.0] 346
Iva frutescens.................0.02. 63/67 | 39.2 || 140] 838/ 84.3
Lactuca scariola.................0. 8.6] 9.6 | 44.2 || 16.1 | 11.1 | 63.4
Rumex acetosella................05. 8.2 | 8.4 | 394 || 180] 11.2] 387.9
Rumex acetosella.............000005 100] 64 | 86.2 || 15.5 | 12.2 | 32.6
Sonchus arvensis....... ... ....... 5.6 | 5.4 | 27.8 |} 15.0] 8.0] 43.1
Verbena stricta............ cece eee 105] 57 | 234 | 17.3] 64] 265
VOT ABS oo ce ice haa Alas ea laches OA 8.2 | 6.9 | 384.6 || 16.9] 95) 37.9

The plants grown in the excessively moist soil did not de-
velop a root system so vigorous or so extensive as those
grown in the dryer soil. The leaves were a lighter green,
and the growth of the plant was less rapid. The general
effect of excessive soil water was similar to that of a humid
atmosphere on a plant which is growing in a soil containing
abundant but not excessive soil moisture.

In comparison with the previous results, in the following
table are given some data obtained by growing plants of
hydrophytic tendencies under the same conditions of light
and air in which the former were grown.

44 STUDIES IN THE VEGETATION OF THE STATE

DRY TO MOIST SOIL VERY WET SOIL

2 |2 2 |2

sf ex | wf ese | 2

Zu jee] s Ze|ae|s
a2) 55/53 | 22/53] 53
Ss (86 |2ao | @B | ee | sa

<q [4 |F 4 j2 |E
Lobelia syphilitica............ 5.7 7.7 | 68.1 12.0 | 11.4 | 57.9
Lobelia syphilitica............ 20 | 10.3 | 52.0 120 | 11.5 | 44.0
Sium cicutifolium......... .. 6.0 8.2 | 860 160 8.5 | 55.5
Sium cicutifolium............. 7.0 8.8 | 514 15 0 9.0 | 45.8
Sagittaria latifolia............ 80 | 13.2 | 52.3 14.0 | 21.4 | 45.2
Sagittaria latifolia............ 6.0 | 11.0 | 46.0 21.0 | 144 | 35.0
IAVOCTAGE a6: cae s bine onan ee eae 6.1 9.7 | 50.9 15.0 | 12.7 | 47.2

Of the plants in the foregoing table, those in the wet soil
were by far the more vigorous, since this is their natural
substratum. Those in the dry soil had adapted themselves
partially to the conditions by reducing the size of their
leaves, and increasing the relative amount of their root
systems. Sagittaria, being nearer a true hydrophyte,
varied the most. All plants showed more or less adaptation
to the dryer conditions. The striking difference of 30 per
cent in the limit of available water shows to what extent this
adaptation had taken place.

5. The Effect of Decreased Light on Non-available Water in
Soils.

Plants were grown in the shade in wet soil in the plot
designated as P-I in the planthouse, and in dry soil in plot
P-II in the same locality. The average maximum light of
these plots was only 1.5 per cent of the standard at noon
June 22. Another shade plot was that of Case II in the lab-
oratory. This had a maximum average of only 0.5 per cent
but the average for the whole period of daylight was only
about one tenth of the light in the shade plots in the plant-
house.

LIMIT OF PHYSIOLOGICAL WATER 45

In the plant house the effect of shade was to increase the
size of the leaves of the plant. This was especially the case
with rosettes of Ranunculus sceleratus, Gaura biennis and G.
parviflora,

The leaves of the shade rosettes not only had larger blades
and longer petioles but they were elevated to a greater angle
with the surface soil. It is hard toaccount for this fact. It
may be due to the stimulus of decreased light causing the
leaves to stretch towards the source of light. It undoubt-
edly increases evaporation from the leaves, thus hastening
the transfer of soil nutrients through the plant. A study of
the comparative anatomy of sun and shade leaves belonging
to the same species, would no doubt show essential differ-
ences in the arrangement of the mesoplyll, in the thickness
of the epidermal covering and in the comparative number of
stomata per unit of leaf surface. The leaves of Ranunculus
sceleratus were modified to a greater degree than those of the
other plants.

The following table indicates the effect of shade in raising
the limit of available water in the soil. The shade plants
show an increase of 0.8 per cent of non-available water in
the dry soil and of 1.3in the wet. The plants are put in two
groups; those grownindry loam, plot P-II, and those in
wet, plot P-I. The amount of available water in the for-
mer varied from 0 to 10 per cent, in the latter from 10 to 380
per cent.

46 STUDIES IN THE VEGETATION OF THE STATE

Plants in Dry Soil Plot P-IT.

IN SUN IN SHADE

2 | eis

wanes B ees a

PLANT Ss = A 3 pi B
Be | Sys 20 | Bae
fa | 32 | 53 | 53
SE SA se EL

A e Z =
Aster cordifolius.................00- 7.2 35.6 8.4 36.0
Gaura parviflora.............00600- 7.4 29.4 7.4 37.5
Gaura parviflura..... ...........06. 6.4 35.5 5 2 19.2
Soncbhus arvensis..............-.008 8.0 43.1 9.9 45.3
Iva frutescens...........-..2e cece 6.7 39.2 74 23.5
Sium cicutifolium .................. 8.8 61.4 8.5 56.5
Lobelia syphilitica...... ........... V7 52.0 10.4 68.1
AVG AB Cle. 3350. (ese Geers anarcocine ele neg 7.4 40.9 8.2 40.7

Plants in Wet Soil Plot P-I.

Aster cordifolius.................005 7.2 35.6 84 45.8
Gaura biennis ..................... 9.4 34.6 11.0 44.2
Ambrosia artemisiifolia............. 5.7 19.2 8.7 32.5
Gaura parviflora ................... 9.3 39.1 9.9 30 0
Thalictrum purpurascens.... ...... 8.1 24.1 9.6 32.7
Sium cicutifolium.... ...........0.. 82 36.0 9.0 45.8
Lobelia syphilitica.................. 11.5 44.1 11.9 57.1
AV OTARG iscsi ain pee tucteamour syle wake de 6.4 30.4 9.7 41.1

Comparison of Plants Grown under Normal Conditions with those
Grown under Shade Conditions.
(Plant Cases. )

Case III (Normal).
Physical Record.

Average air temperature... .. 2... cece ete cece eee eeeeee 76°
Average relative humidity .............cccccccceccceeeeecnateeees 55%
Average soil temperature..........0. 0. cc cece cece e nce ence eens 70°
Average soil moisture......... HOI Wit antics Geena digsede a seatciate ae rae wEOS 14.7%
Average maximum light ......... 0... cece cece ese e cece en eees 12.0%
RESULTS NON-AVATLABLE © PLantt

Average 9 plants... 6.560 :csscvovewewase bedi ea 4.8% 80.4%

LIMIT OF PHYSIOLOGICAL WATER 47

Case II (Deficient in light, other conditions normal. )
Physical Record.

Average air temperature. ......... 00. c ccc cece cece eee ceeeeseeees 74°
Average relative humidity. ..............000.0 cece cee ceueeeeeuees 72%
Average soil temperature..... 0... cece cece cece ene naar eeeee 66°
Average soil MOiStUrE.. 1... cece cee recente eene eaten 14.6%
Average maximum light......... 0... c cece cece cece eee e nese enes 0.5%
mst aera
Avyorage:9 plants... cccaccwave gece ee ad wean ewe 9.0% 41.5%

These give the wide difference of 4.2 per cent in the
amount of water non-available for the use of the plant. Such
intense shade brought about a pathological condition in Case
IL.

The plants in plots P-I and P-I] were under precisely
the same physical conditions excepting that of soil water.
They received several times more light than those in the
shade in Case II. The latter were ina diseased condition
and would never have borne fruit had they been permitted
to live. The former adapted themselves in a greater or less
degree to their conditions and showed every indication of
fruiting had they been allowed to continue their existence.

It cannot be definitely determined when a plant ceases to
be able to adapt itself to its conditions, that is, just when a
plant passes from a normal to a pathological condition. If
a plant is changed from a sunny situation into one of con-
stant shade there can be little doubt that it suffers from the
effects for a time, and during this period must be in a path-
ological condition. If the shade is not too intense it may so
adapt itself to its conditions as to be able to perpetuate its
species even wheu its condition is not one of health.

When one plant is unable to witharaw as much water
from the soil during drought as another of the same spceies
situated under different air or light conditions, it cannot be
safely maintained that this is because the one in the less
favorable condition has adapted itself to its new habitat by
a change of structure. Although it has a modified structure,

48 STUDIES IN THE VEGETATION OF THE STATE

its protoplasm may not be able to function properly, and as-
similation may be so hindered by a lack of proper protoplas-
mic stimuli that the plant is unable to get and use as much
food as it could in a more favorable habitat. It is no doubt
true, that after several generations a plant may fully adapt
itself to such a change, and then its higher limit of non-
available water mav be due to certain changes in the func-
tion and structures of the organs of the plant.

6. Lffects of Soil Texture and Composition on the Limit of
Available Water.

Before entering into a discussion of this subject, a summary
will be given of all the results of experimentation which
bear directly upon this problem. Since the plants compar-
ed grew under similar physical conditions in each in-
stance where the different soils are compared, it is not con-
sidered necessary to give with any table the data for the
physical factors.

The following averages are from five species, viz:
Helianthus annuus, Hordeum vulgare, Phaseolus vulgaris, Ricinus
communis, and Zea mays, all grown in the plant house.

Comparative Plot ITT.
Average of Thirty Pots.

SOIL NON-AVAILABLE WATER IN

WATER, % PLANT, %
Sand iy aidereiinn SG) abl anaaaueeai cee 0.31 43.8
CN ayes eciat’ wapialgue lin Bor sewasaiacne sanded 8.6 51.3
TO CBB i ine, cataract le aor ease oie. 9.2 62.7
TOOT vecatag ck Senin aisle ad entneueveme 9.5 548
AUNUS oe rewencss saae xeon. see 10.7 48.4
DBINE: siete’ Sn Ra ane dane ek Soha -ataoks 14.0 57.4

LIMIT OF PHYSIOLOGICAL WATER 49

Comparative Plot LI.

Three species, Phaseolus vulgaris, Hordeum vulgare, and Zea
mays, grown in the plant cases under four different combin-
ations of physical factors.

Sih NON-AVAILABLE WATER IN
WATER PLANT
THOOB8 35 4 sis crate sehen bee Rie Oe 8.4 41.7
DSO ADM ccc dg wisinneldtcntaicdaasivemaeaars 8.4 45.1
ADs rdw ivialioutaias drs ceenreetanp countess y 0.49 59.2
Comparative Plot I
(Thirteen species grown im the planthouse. )
NON-AVAILABLE WATER IN
Sor WATER PLANT
WSO OSS. aisle qeg dion 2a hia gud oeaticandohuandc views 5.9 30.1
OGM 3 betas daw t po aucioseudis MGA tes 5.5? 31.6
Sab acacocu eatin rnanen A e Sane? 0.65 32.1
Plot P-1.

Below are given the results obtained from thirteen species
grown in the plant house under similiar conditions except soil.

NON-AVAILABLE WATER IN
Bore WATER PLANT
ClO ys 23.22 saacdcesnakwiet eek ea poses 7.3 35.2
LOAM) 54,05 bcc ticouradane ead-sa eae 8.5 41.1
DANG 2 eccisattogelenten Pesee wea sosiae 0.8 29.6
General Average for All Plots.
NON-AVAILABLE WATER IN
Sonu WATER PLANT
AN a chid asGcd os ede SARI e SSS 2H 0.5 42.1
TAOCS Bi. ais acs vasewiad aaa aac SOOT 7.8 41.6
CIB Ysa aaic-etenmicacte pee de wmanemean heats 19 438.4
Loam ...... 80 43.1
Humus 10.7 48.4
Saline: ss snsuedud v's sang wigan areas cl 14.0 57.4

50 STUDIES IN THE VEGETATION OF THE STATE

From the foregoing tables it is easy to determine the
relative positions of loose soils used in a scale of limits. If
placed in order of the highest to the lowest, the order is
saline, humus, loam, clay, loess, sand.

Sand lowers the limit of available water. All the results
from sand averaged 0.3 per cent, it being air dry when the
plant was near the death point. The sand used did not con-
tain sufficient silt to hold much hygroscopic water, for it con-
tained less than one per cent of silt. The presence of sand
in the soil has a direct effect in lowering the limit as was
shown by plants in a few pots which had sand mixed with
either loam or clay. It must not be supposed, however,
that because a plant assisted by evaporation and gravity
might take water out of sand to less than one per cent when
it leaves eight per cent in loam under the same conditions,
that sand is a better soil in which to grow plants in a dry
climate. Sand being so porous evaporates water very read-
ily, the rate of evaporation decreasing with a decrease in
the size of the grains. For this reason it evaporates water
more rapidly than other soils. It also allows water to pass
rapidly through it by gravitation to the stratum beneath,
since the forces of capillarity and surface tension are not
sufficient to retain the water as in other finer soils. The
soil which absorbs water most quickly loses it by evapor-
ation and gravitation most rapidly. It also loses the nu-
trient soil solutions rapidly by leaching.

The finer soils like the clays hold water the most tena-
ciously. This quality tends to raise the limit of water by
increasing the hygroscopic water. In such scils the forces
of capillarity and surface tension as they are designated by
soil physicists may be arrayed against the forces of solution
operating in the root hairs of the plants, and tend to negate
the latter. If it be maintained that the great difference be-
tween the limit of the fine clayey soils and the coarse sandy
soils is due solely to the relative increase of these two forces
in the former, the limit of von-available water in saline,
humus, loam and loess should have been lower than that of
clay soil and higher than that of sand, for these soils contained

LIMIT OF PHYSIOLOGICAL WATER 51

less silt and clay. Hence these were more porous than clay
and the forces of capillarity and surface tension in them
must have been less powerful. Since the limit of these soils
is higher than that of clay there is evidently another disturb-
ing factor, especially in the case of the saline and humus soils.
This must be attributed largely to the increased amount of
electrolytes or soluble salts in the soil. The following table
of ratios includes a comparison of the soils taking the per
cent in loess as a basis and calling this1.00 in each column.
Itmay be seen that the per cent of soluble salts varies ap-
proximately with the increased amount of non-available wa-
ter. The variation of the other soil qualities shows no uni-
formity, when compared with each other or with the non-
available water.

Table of Comparative Ratios.

oa

& n 3 So ni
S = |3 |e |8e/2
au(2| 2/2, (28)8
SOIL Eo © nluws,| 22
fel o | a as leel as
SE) 2 | 8 |} #3 |sa|s8
A n ia i@) ioe} >
Ca eee 4} 624 | 1382 12
100 100 100 100 100 100
101 133 107 33 106 163
104 125 100 75 104 293
137 183 57 221 90 415
179 417 104 88 114 147

After much effort to combine these ratios to get a common
ratio which would correspond to that of the non-available
soil water, it was found that the ratios of soil solution were
the only ones that compared directly with those of the non-
available water. It was found that if the per cent of so-
lution be taken as a basis, and the square root extracted and
multiplied by 20, a set of ratios or numbers were obtained

52 STUDIES IN THE VEGETATION OF THE STATE

which coincided approximately with the per cent of the non-
available water in each soil. The following are the ratios:

a 8 ©
SOIL ee | 8 | & q 3 a
a | 4 | ) =) x a
| |
% of Non-available Water....... | 0 | 7.8 | 7.9 | 8.0 | 10.7 | 12.0
20V% of Soluble Salts...........)...... 70 | 801 781 9.4 | 141

The amount of soluble salts in the sand was so low that
the chemist did not determine it. It was very low,
posssibly not much greater than that of the tap water used
in watering the plants growing in it. This being the case
the same rule would hold as for the other soils, viz., the per
cent of non-available water in the soils increased as the square
root of the per cent of the soluble salts. Since the per cent of
soluble salts in the soil increases directly as the per cent
of water in the soil decreases, the increasing density of the
soil solution would tend to reduce the amount of available
food for the plant, and since the supply of watery foods for
it varies with difference in density existing between the sol-
utions in the protoplasm of the root-hairs and that of those
in the soilthe protoplasm would take less water from the soil
solution just at the time the plant needed a greater water
supply. The fact that evaporation from the plant is aiways
excessive in times of drought wouid hasten the result. On
the other hand the rapid evaporation from the leaves, when
a plant is losing more water than it is getting would tend to
concentrate the solutions in the plant and increase their os-
motic efficiency in taking in water from the soil solutions.
These questions are of great interest and importance and
should be investigated thoroughly with reference to the plant
in its relation to the soil.

The observations made inthe field during August 1900,
brought out a fact of considerable importance, viz., that her-
baceous plants growing in hard soils could not root as deeply
as those growing in loose soils. Plants are enabled to grow
rapidly only when they can develop large and vigorous root

«

LIMIT OF PHYSIOLOGICAL WATER 53

systems which may supply them with the nutriment necessary
for rapid growth. In hard soil a plant is hindered in the
development of its roots even from the beginning. As a re-
sult it does not grow so large as a plant in looser soil because
it does not have the means to absorb water nor can it draw
from such a large and varied soil area. Asa result, in
periods of drought, it is first to die.

The limit of physiological water for various plants in the
field was determined for both hard and loose soils. The
average results give a slightly higher limit for plants in
hard soils. The results for the herbaceous plants when
averaged give 5.9 per cent as a limit in hard soils, and 5.2
for loose soils. Ten species of grasses have an average limit
of 6.8 per cent in hard, 6.4 per cent in loose soil. These
results may be slightly inaccurate because the soils compared
were from different localities and probably differed slightly in
composition and porosity. The plants were taken from sim-
ilar conditions of heat, light, and physiography.

The soils used in the comparative plots were of a loose
texture, care being taken in filling the pots not to pack the
soil, which was allowed to settle and become denser by grav-
ity. The time of experimentation was short, being less than
two months, and noneof the soil became hard. This enabled
each of the plants to root throughout the pot, and added
much to the accuracy of the results.

7. The Recovery of Plants from Drought Effects.

When a plant has suffered from loss of water by wilting
badly, it may be revived by watering it. One box of potted
plants in the plant house, grown under nearly normal condi-
tions, was allowed to dry until the plants were wilted badly,
in fact were dying, for excessive wilting is but the condi-
tion preliminary to death. Water was then sprinkled upon
the soil in sufficient quantity to make it moist enough either
to fully or to partially revive the plants. Again the plants
were allowed to dry out, this time tothe death point. Deter
minations of non-available water in these pots showed that

54 STUDIES IN THE VEGETATION OF THE STATE

the plants had never fully recovered from the first drought,
for they were unable to withdraw as much water from the
soil as similar plants which had been allowed to die without
reviving them. The increase of the limit ranged from 2 to
7 per cent, varying possibly with the amount of injury done
to the finer roots and root-hairs of the plants. The results
indicate that in such instances the root -hairs are probably
destroyea

The following tables of data show the effects of wilting
on some of the plants in Comparative Plot ITI. Under the
heading “Wilting Plant’ is given first the amount of water
in the plant at the time it wilted badly from drought, second
the per cent of water in the soil at the same time, and under
the heading “Dying Plant,” first the amount of water in
the dying plant, second that in the soilat the same time,
taken when the plant was dying after having been partially
revived from the first excessive wilting. In the last in-
stance the plants were revived by adding water to the soil.,.
care being taken not to wet the leaves of the plant.

LIMIT OF PHYSIOLOGICAL WATER 55

Average Physical Conditions.

Air teM peratures cs csweswaveytiecas oedeeasiw es tae see ereewNa es o4 98°
Relative: Humidity ices pac cadas cedodduna oo doceeses vadngedeaet ee 47%
Soil tem PSratuT er iwy sca vs axasasye wauioscinew masa onl waa loneaden ween a wales 105°
Light: (MAXIMUM)... ciesescod a enews eeee Gade a Teo Redes see aeededs 35%

Phaseolus vulgaris.

WILTING PLANT DYING PLANT
SOIL a P

q » qd w

B a ‘h iE

= iv S a

e | 8 Sus
SANG acasciouts Gas. a Sayeead kuhvereiesorees 17.2 80 0 19.8 53.7
Naat incal cea divoeuaden wri rnmnies 8.5 739 86 51.8
UGS 5.5 oatscc rie alanis ws BNO 93 810 11.0 32.1
WOCBSixcislaytsecds usted aera awe 84 85.6 8.7 52.8

Helianthus annuus
LOAN 5 jatzisadcaed.4.3.2-Sh Gade seston e 11.6 87.6 11.2 61.4
DBlING sich én. naag.b soa ueadanacneinde 16.1 85.4 127 59.0
GHEY seca eter ease narration warn as 91 84.9 9.3 60 8
LOG8S icici eau ae evant Wea 109 815 10.2 55.2
BUMiS cede ewes aawnae gees 14.5 79.2 11.8 59 6
Ricinus communis

DAG es o.oo: suas ok sales ea ee nee 12.0 76.5 12.4 60 0
CHAS 3 cera evakow arneralals Wales cess nctiors 9.8 80 6 108 55.9
LGOBS ihc ececen ys wrod ead aeons ok 78 74.3 10.9 49.6
WMS ao caidas aah ed 12.1 79°7 123 61.9

These plants were subjected to more severe drought than
those first mentioned in this chapter. In each case the limit
of physiological water was noticeably increased and the
plants died in a per cent of soil water equal to or greater
than the soil contained at the first period of excessive wilting.
The limit at which they died was higher than the limit at
which they die when not revived at any time during the
period of drought.

56 STUDIES IN THE VEGETATION OF THE STATE

The fact that after being revived the plants could not

reduce the physiological water to as low a limit as before
indicates that the absorptive system of the plant had
suffered serious injury before they were revived. it must
be that the root-nairs and even the finer roots had been killed.
If this be the case in nature, a temporary shower could not
furnish the plant with sufficient water to grow new root-
hairs, and the plant would continue to die in spite of the
slight addition to the soil moisture.
‘ From the results it might be inferred also that in times of
drought a shower might beof absolute harm. In some local-
ities in the West many farmers believe that in times of
drought a small shower not sufficient to “wet down the soil’’
is an injury to the crop. But this can hardly be true since
the shower checks the rapid loss of water from the plant by
evaporation and enables it to live longer and may be the
cause of prolonging its life until heavier rains fall.

8. The Limit of Physiological Water; Variations in Different
Genera and Species.

The notes from experimentation indicate in a general way
variations in the limit of physiological water corresponding
to the natural habitat of the plant. The limit for meso-
phytes for loamy soils falls generally between 5 to 11 per
cent.

Mesophytes with xerophytic tendencies may drop below
this general average in their limit while, those bordering
on hydrophytes in their habitat may have a limit even
higher than this. By arranging the limits ina descending
series commencing with amphibious plants, or those that
root in mud, and passing through the mesophytes to
xerophytes, the amount of non-available soil water in loam
decreases from 20 per cent for some amphibious plants to an
air dry soil as a limit for intense xerophytes.

Fleshy plants have lower limits than woody ones. Nas-
turtiwum and Coleus, although not true succulents, retain
water so tenaciously in their stems that the soil becomes
almost air dry before they die.

LIMIT OF PHYSIOLOGICAL WATER 57

The following table gives the limit for several typical plants
ranging from amphibious plants to mesophytes of xerophytic
tendencies.

Table of General Variation.

PHYSIOLOGICAL WATER IN
PLANT WATER, DYING PLANT,
% %
Potamogeton lonchites................. 248 32.8
Echinodorus cordifolius................ 19.6 48.5
Sagittaria latifolia............ 02.0... 15.6 44.6
Ranunculus sceleratus................. 10.5 57.1
Lobelia syphilitica................. ie 10.3 30.1
Panicum walteri................0..0005 8.7 27.2
Eclipta: alibais. 2tcciis' iow ensasave waaee ace 7.5 45.1
Helianthus annuus..................00 6.5 36.5
Ambrosia artemisiifolia.. .............. 5.4 24.3
Atriplex argenteas. os ssewieaie caeee 42 26.6
Nasturtium officinale.................. 3.7 33.4
Coleus bluméi........ 2.0.0... eee 3.0 70.0

Thus we see that not on'y do plants of different genera
vary in their limit but also species of the same genus.

Some instances of specific variation are given in the fol-
lowing table.

Table of Specific Variation.

PHYSIOLOGICAL | WATER IN
LANE WATER, LIMIT | DYING PLANT
Panicum walteri..............0.ee eevee 8.7 27.2
P. proliferum ........ 0... eee eee eee 7.8 39.4
P. scribnerianum.................0000% 7.3 27.8
PCRus-Calli. enavateusgts quneeua vases 7.2 35.6
Be WIT PAtUM peisc oe pada ew ae Hoon ee eee 6.8 23.0:
Plantago major..............e cee eee ee 77 25.8
PoTUgelilssccsusvassciaavenactogeesrges 5.9 27.0
P. elongata............. LRsterpaae wins See 5.8 22.2
Ei DUYSHILscaieig: atamad Samakiadew ans ss 5.5 41.0
Rumex crispus............00 ee cece eens 8.3 35 4
R. acetosella..... 00... . ccc eee eee ees 6.6 34.8
Sporobolus longifolius................ 5.8 20.9
S. VAGINIMOLUB: wee cc ceccacevonewaters ss 4.4 18.9

58 STUDIES IN THE VEGETATION OF THE STATE

The few results obtained from hylophytes or plants of the
woods, and poophytes or plants of the meadow and prairie,
indicate that the former have a higher limit than the latter.
The plant house, it should be remembered, approached nearer
to hylophytic conditions, and this favored shade-loving
plants. Sun-loving plants on the other hand by being placed
under the semi-shade conditions of the plant house tended
towards a higher limit than if under more natural condi-
tions. The following table gives the results obtained with

violets.

NON-AVAIL- WATER IN
PLANT ABLE WATER DYING PLANT

Viola scabriuscula..................05. 9.0
Wee ODUQUAS seaeice,acacacke'¥ 2:0 facdeavtitvivaueiossleia ed.des 8.9 39 7
Vi. pedatitida., 2.0. was pakenwuumns ea nee 7.5 2

The first species grows in protected places, the second in
both sunny and shady localities, and the last in the open
prairies. These data as well as others indicate that the
limit of hylophytes will average higher than that of poo-
phytes. Since shade has the effect of raising the limit of
available water it is to be expected that in the structural
differences between poophytes and hylophytes the latter have
shade adaptations which are of such a nature as will lessen
the ability of the plant to withstand drought.

D. DROUGHT EFFECTS. THE MANNER IN WHICH MANY
PLANTS, PRINCIPALLY MESOPHYTES, DIE.

The plants studied were principally herbs of both monocy-
clic and dicyclic types. The behavior of the two types in
times of droughtis slightly different. Certain drought effects
are common to all plants. In general, if the epidermal cov-
ering of the plant is uninjured at the beginning, death takes
place more slowly and the order in which the different or-
gans suffer loss of water is quite constant. If any portion of
the plant has suffered mechanical or structural injury, this

DROUGHT EFFECTS 59

order may be changed since the injured member loses water
more rapidly than any other part of the plant and, as a re-
sult, is almost certain to die first. Ifa leaf has been injured
by having the epidermis broken by the force of the wind or
by the impact of hail, if it has been punctured by sucking
insects or lacerated by biting insects, it commences to die
from the point of injury, as soon as the plant fails to obtain
sufficient water to keep its tissues turgid. The stem may be
similarly affected by such injuries. The rootis often in-
jured by insects, and even more frequently by the filaments
of parasitic fungi. Plants suffering from root injuries are
almost certain to die from the root upwards.

When the plant is healthy and vigorous, and has not re-
ceived any mechanical injuries, the growing point in stems
and rosettes is the last part to die, because the meristem
cells hold their vitality more tenaciously than other cells
and are able to live to the last. In succulent plants they
even seem to be able to draw upon the neighboring cells for
water. This may be the casein all plants. When the period
of drought is prolonged but not intense, the roots of fibrous-
rooted plants commonly die before the stem, but after all or
most of the leaves have perished. This is the way many
monocyclic herbs die; Atriplex argentea, Phaseolus vulgaris,
Euphorbia marginata, Ambrosia artemisiifolia are good ex-
amples; Phaseolus, Coleus, Gaura, Amorosia and a number
of other plants partially adapt themselves to slow drovght
by dropping their leaves, the oldest first. In this way they
check rapid evaporation and soon reduce it toa minimum.

Dicyclic herbs often have more or less fleshy roots which
hold water tenaciously in times of drought; especially is
this the case when the plant is inthe rosette stage. The
leaves during this period of the plant’s existence die much
sooner than the roots.

When a herbaceous plant sends up a stem preparatory
to flowering, the growing point of the stem holds water in
its cells tenaciously, and where the plant has not suffered
from physical injury, the leaves die first, the root next,
then gradually the stem dries out and last of all the young

60 STUDIES IN THE VEGETATION OF THE STATE

cells of the growing point perish. But when the plant has
reached the flowering stage, the last part of the plant to die
is the immature fruit, the order of dying for the other organs
being the same as before.

Plants which propagate by means of bulbs and tubers often
suffer drought with only a temporary injury. Sagittaria
latifolia continues its existence principally by means of tubers.
One of the first things a saggitaria plant acomplishes after
two or three leaves appear is to send out an underground
shoot or stolon which forms at its terminus a bulb.
These bulbs are usually mature long before the plant pro-
duces flowers and fruit, and when a young plant suffers from
a period of drought all the reserve energy of the leaves is
apparently transferred to the tuber which matures as the
other parts of the plant die. Bulbous plants behave ina
similar way: a young bulb is formed which matures as the
other portions of the plant dry up from loss of water. Bulbs
and tubers are very resistent to the effects of dry soil and
may retain their vitality for months under conditions of
most severe drought.

Woody plants like trees and shrubs usually have roots
which penetrate the earth toa great depth. When such
plants die from drought, the root is the last portion of the
plant to die. The same appears to be true in case of most
pleiocyclic herbs, having either fibrous roots or a woody tap
root.

In case of death from sudden drought , such as occurred
with the plants placed in the xerophytic atmosphere of the
laboratory, in some monocyclic herbs the root was the last
organ to die. The excessive evaporation from the leaves
hastened the death of the stem and growing point. Drought
rarely takes place so suddenly in nature.

The root seems by far the most adaptable part of the plant,
and the leaves stand next inorder. Plants growing in dryer
soil usually have proportionately larger root systems, pro-
viding the degree of dryness does not become so excessive
as to prevent the development of the plant. In the case of
mesophytes in nearly every instance noted, excessive water in

CONCLUSION AND SUMMARY 61

the soil retarded the formation of the root system. This of
course is to be expected for there must be a most intimate
connection between the root and the medium in which it
grows. The very existence of the plant is dependent upon
its food supply as received from the air and soil and circu-
lated through the tissues by means of water received through
the roots. Under varying conditions of soil moistures such
as those in which the mesophyte finds itself it can not be too
conservative in the modification of its root system, and the
meager observations made indicate that our ruderal meso-
phytes have a root system which is varied directly with the
conditions of soil moisture and food supply. This is a most
interesting and fascinating subject for future investigation.

II. CONCLUSION AND SUMMARY.
A. WATER IN PLANTS AND SOILS.

1. Water in Soils.

The amount of physical water in soils varies directly with
their water-retaining capacity and the chief known factors
affecting the water capacity are gravity, capillarity, and
surface tension acting within the soil, and evaporation acting
upon the surface of the soil.

The amount of physiological water in soils varies directly
with the amount of physical water held in the soil and in-
versely with the amount of hygroscopic water. The adapt-
ability and vigor of the plant varies its power to draw water
frum the soil. The kind, quality, and texture of the soil and
the density of the soil solution are important variants in
determining the limit of physiological water.

The amount of water in the soil non-available for the use
of the plant is dependent directly upon the ability of the
plant to withdraw water from the soil. The ability of the
plant is measured by its inherent nature as manifested in the
form of protective structures, by its adaptability to its chang-
ing life conditions, and by the vigor of its protoplasm. Soil
composition and soil texture affect directly the ability of the

62 STUDIES IN THE VEGETATION OF THE STATE

plant to withdraw water from the soil. The vigor of the
plant is lessened by light, heat, temperature and moisture
effects which vary too widely from the optimum necessary
for the plant, and such physical factors are indirect causes
in increasing or decreasing the amount of non-available
water in the soil. The limit of physiological water varies
directly with the square root of the per cent of soluble salts
in the soil.

2. Water in Plants.

The per cent of water in the tissues of the plant is usually
the greatest in seedlings, and decreases gradually as the
plant grows older. The individual plants containing the
highest per cent of water are not necessarily the healthiest,
since the most vigorous growing plants contain a lower per
cent than less thrifty ones. Shade plants and plants grown
under humid conditions have a relatively high per cent of
water, due probably to a poor development of the fibrovascu-
lar system. Plants grown in different soils indicate the fol-
lowing series beginning with the soil bearing plants of
the highest water content, viz., sand, loam, saline, clay,
loess, humus. The most watery plants were more often
attacked by fungous plants than those less watery.

Mesophytes apparently lose water when first wilting in
almost the same ratio by weight as the soil. This may
indicate that the plant gets little or no water from the soil
after it begins to wilt excessively, and that the root system
is already beginning to die at the extremities. Hydro-
phytes probably lose weight more rapidly than the soil.
Xerophytes lose weight very slowly when subjected to
drought, and some may retain most of the water in their
tissues even after the substratum is air dry. The tenacity
with which the water in soils resist the absorbent action of
the root hairs of the plant varies in different soils. The
soils of experimentation arranged in order of their resist-
ance from the highest to the lowest are: saline, humus,
loam, loess, clay, sand, The chief probable factors of vari-

CONCLUSION AND SUMMARY 63

ation are capillarity, surface tension , and varying concen-
tration of the soil solution.

The per cent of water in dying plants varies not unly with
the species, but also with the individual. Seedlings die
with a greater per cent of water in their tissue than older
plants, and they usually leave an increased amount of non-
available water in the soil. Mature plants when dying con-
tain the minimum per cent of water. Shade plants as well
as those grown in humid air die with a higher per cent of
water in both soil and plant. Dryness of atmosphere
modifies the growing plant so that it may live on a slightly
lower per cent of water in the soil. Rosette plants of xero-
phytic tendencies contain less water in their tissues when
dying than rosettes of hydrophytic tendencies, and also
may die ata lower per cent of soil moisture. The same
observation was made with regard to plants of both groups
with immature stems.

B. NON-AVAILABLE WATER IN SOILS.

Heat (and light) below or above the optimum for the plant
affect it unfavorably, decreasing its ability to withdraw
water from the soil during drought, increasing the non-
available water.

Increased relative humidity of the air, when high, in-
creases the size of the leaves and retards the development
of the root system. Transferring a plant froma humid or
moist atmosphere suddenly into a comparatively dry one
hastens the death of the plant, especially when the soil at
the same time is deprived of its water supply. In both the
former and the latter case the plant dies ata higher limit
of non-available water. Excessive soil moisture during
the growth of a mesophytic plant tends tu retard develop-
ment of the root system and to raise the limit of non-avail-
able water. Where mesophytes of strong hydrophytic ten-
dencies or where hydrophytes are placed in both dry and
wet soils the plants seem able to adapt themselves partially
to their new soil conditions and die at a lower limit of soil

64 STUDIES IN THE VEGETATION OF THE STATE

moisture than under normal conditions. Such plants reduce
the size of their leaves when grown in dry soil.

The influence of shade upon plants accustomed to full sun-
light is such that they die at a higher limit in times of
drought. This fact was shown by the results from both
plant house and fields. It cannot be decided as to whether
any of the plants in the experiment had fully adapted them-
selves to shade conditions and whether the consequent
change in function and structure was the cause of the in-
creased amount of non-available water inthe soil. Since the
change of habitat was unfavorable to the plants, there is
the possibility that most of them were still suffering from
the lack of sufficient light stimuli and the protoplasm as a
consequence was unable to function normally. Since shade
plants contain a higher per cent of water in their tissues,
it is possible that the lessened density of the solutions in the
protoplasm of the root hairs lowers the ability of the plant
to take water from the soil solution. This tends to raise the
limit of non-available water.

The limit of physiological water is varied by several fac-
tors involved in the composition and texture of thesoil. The
great difference in the limit of sand and clay might be attrib-
uted to the increasing negative effect of capillarity and sur-
face tension in the latter This would tend to reduce the
absorption of water by the root hairs. In case of humus, loess,
saline and loam soil there are very evidently other disturbing
factors. In these soils a very important factor must be that
of the variable density of the soil solution. Diosmotic inter-
change, aside from other forces, varies directly with the
difference in density between the soil solution and the solu-
tion in the protoplasm of the root hairs; asa result the plant
may obtain less and less water from the soilas it dries out.
Finally the solution in the soil may become so concentrated
that it actually extracts water from the roots of the plant.

Plants wilting excessively from drought when slightly re-
vived by watering are not able before they die to remove as
much water from the soil as plants dying without ever hav-
ing been revived. Thisis apparently due to the loss of the

CONCLUSION AND SUMMARY 65

root hairs in times of excessive wilting. In nature a shower
which revives the plant but does not furnish sufficient water
to the soil for its growth will not enable it to push out new
root hairs, and as aresult only permits the plant to live
longer by retarding excessive evaporation.

The ability of plants to take water from the soil varies in
an ascending scale from hydrophytes, through mesophytes,
to xerophytes The limit of available water for a plant, in
a general way, coincides with the physical conditions of its
habitat. This being the case we have variations not only
among genera but also among species, and even among indi-
viduals, depending upon the physical conditions under which
the plant has grown and upon tendencies inherited from its
ancestral forms. The relative activity of the protoplasm is
a very important factor in determining the amount of water
that a plant may abstract from the soil in times of drought.

C. DROUGHT EFFECTS.

Herbaceous plants, both annuals and biennials when
affected by slow drought usually die in the following man-
ner. The older leaves of the plant perish first in order of
their age, the younger leaves living to the last; the finer
roots die first, then the coarser roots, finally the stem and last
of all the growing point of the stem, or if the plant is flower-
ing, the immature fruit. If a plant of either type has suf-
fered a structural injury, it is very apt to die from the point
of injury, since it loses water more rapidly at this point.

Trees and shrubs and pleiocyclic herbs lose their aerial
organs first, the roots being usually the last part of the
plant to die. Bulbous and tuberous plants although imma-
ture form bulbs or tubers rapidly when caused to die by
drought. Propagation has become the favorite means of
continuing the existence of these plants.

The structure of the protoplasm of; the meristem cells in
the growing point of the stems and in the immature fruits of
herbaceous plants, as well as in others, must be of such
chemical and physical nature as will enable these cells by

66 STUDIES IN THE VEGETATION OF THE STATE

osmotic action or otherwise to take up and retain the watery
solutions from older and less vigorous cells. Unless some
action of this sort takes place the growing point of the stem
would always die first, and not last.

SPECIES LISTS

AND

SPECIES SHEETS

SPECIES LISTS—NON-AVAILABLE WATER 69

SPECIES LISTS—NON-AVAILABLE WATER.

At the close of this explanatory chapter are two lists of
species, the first giving the average results from plants
grown under the full light in the plant house, and the sec-
ond a list of results from plants in the fields about Lincoln.
In growing a large number of plants, except in the compar-
ative plots, it was impossible to keep the soil equally moist
in all the pots, the amount of water in the soil averaging
from 10 to 25 per cent. Asa result some of the pots with
smaller plants maintained a higher per cent of soil moisture
than others with larger plants. The conditions of air and
soil temperature were quite uniform. Some of the results
obtained from a few plants are placed in the ‘‘Species Sheets”’
immediately following the ‘‘Species Lists’. Hereare given
the results of work from both plant house and laboratory.
These results vary as might be expected, since the plants
are grown in different physical conditions as regards soil,
air, temperature and light. One slight source of variation
is the injuries received by many plants from the punctures
of small insects infecting the plant house; another is that
caused by parasiticroot fungi. The average results of plant
house and laboratory plants is somewhat higher than that
for plants in their natural habitat, yet not so great as might
be expected, when the greater humidity, the deficient light
of the plant house and the effects of the injuries from insects
and parasites are taken into consideration. The plants in
the field are also subject to injuries from insects and fungi,
and in addition are more apt to suffer mechanical injuries
from the wind. Where the results seemed to depart widely
from the limit of plants of similar habitat but different
species, the error was directly traceable to the mechanical
or structural injuries received by the plants before or dur-

70 STUDIES IN THE VEGETATION OF THE STATE

ing the period of drought from one of the sources indicated
above. Such results were omitted in the general average
for each species.

It may be well to question the accuracy of the results
obtained in calculating the limit of physiological water,
where the water in the dying plant was less than 20 per
cent in grasses and less than 25 per cent in other plants,
since it is probable that most plants have ceased to obtain
any water from the soil by the time there is less than 30 to
50 per cent of water in their tissues. This isa problem
for further investigation since the results indicate that there
is a variation in the amount of water in the plant when it
dies, not only in different species, but also in the different
plants even if taken at the same age. Such variation is
probably caused by differences in the structure of plants
growing under different physical corditions. The whole
matter is also inseparably connected with the vigor of the
plant and its adaptability to its surroundings.

SPECIES LISTS—NON-AVAILABLE WATER 71

LIST OF SPECIES.
(Average results obtained under Plant House conditions,
plants growing and dying in loam under similar physical
conditions. )

=| ’
a WATER IN PLANTS a
25 Bg
NAME z 9
pa) ge ee ee
Ee | & 3 6| 28
E A = Z
Abutilon abutilon Gaertn.............. 5.6 83.380 |......... 1
Acnida tamariscina (Nutt.) Wood...... 4 25.1 91.0 5
Alsine media Le... . eee cece eee eee 7.9 29.9 85 0 3
Althaea officinalis L.. .. ......... 0... 7.5 50:0 bien gs. ants 1
Amaranthus hybridus L............... 7.5 TD Neg eaqse avers 2
Ambrosia artemisifolia L............. 5.4 24.3 80.0 23
Ambrosia trifida L..... ............0.. 6.4 BO. Mevcvaeare anges 4
Andropogon provincialis Lam.......... 6.3 St Fy ne eee 1
Asclepias syriaca L......... eee eee eee 8.4 260 Wiwawnesvae 1
Asparagus officinalis L................. 7.0 63:3 | gee ennee 1
Aster cordifolius L................008. 6.9 82:8 |vsaawexare 4
‘Aster paniculatus Lam................. 8.8 PSOE Wecscs satya ive 2
Atriplex argentea Nutt... ........... 4.2 26:65 Woes vests 4
Avena Sativa L........ cece eee 6.2 40.1 90.0 11
Beta vulgaris L. (Sugar beet)........... 5.9 87.7 91.0 11
Bidens frondosa L .......... ...e ee eee 7.8 39.2 84.0 8
Bouteloua curtipendula (Michx) Torr ..| 4.6 G40 ‘Wirgn giagaes 1
Brauneria pallida (Nutt.) Britton ..... 6.6 B36 Vcasie dace 1
Brassica nigra (L.) Koch............... 6.6 TES Pes cisarvane: 1
Brassica oleracea L.............0. 00005 58 BBL Weegee as 2
Capnoides aureum (Willd.) Kuntze..... 7.7 42.9 87.0 4
Cardamine hirsuta L................. 6.0 21.9 72.0? 2
Carduus altissimus L........ ......... 6.5 TO deeded jeace 1
Carex straminea Willd............ ... 6.4 16.6 fees 1
Carex vulpinvidea Michx.............. 7.5 B05 j..... oe. 2
Cassia chamaecrista L............ .... 6.4 WS Wssdnes cas 3
Cassia marilandicaL ...............06 7.0 BO.) | Wien aten 8
Cenchrus tribuloides L..............- 6.6 25.6 ane culecks 5
Chaetochloa glauca (L.) Scribn......... 7.5 31.3 82.0 15
Chaetochloa italica (L.) Scribn......... 6.8 B44 dh vee ciutd 2
Chaetochloa viridis (L.) Scribn......... 5.3 36.7 78.0 21
Chrysopogon avenaceus (Michx.) Benth] 8.8 460 |......... 2
Coleus blumei'Benth.................6- 3.0 MOO fiacirsastovasscs 1,
Cucumis sativus L..............00.0 eee 10.8?) 18.6 |......... 1
Cucurbita maxima Duchesne........... 69 BOLT Miriea eons 4
Cyperus aristatus Rottb................ 7.2 | dead |......... 1
Draba caroliniana Walt.............. 7.8 HORT lh oacticaeatat 2
Echinodorus cordifolius (L.) Griseb....| 19.6 48.5 87.6 2
Eclipta alba (L.) Hassk.....-.......... 7.5 45.1 87.6 4
Elymus canadensis L... .... ......5.- 5.9 180 80.0 11

72 STUDIES IN THE VEGETATION OF THE STATE

LIST OF SPECIES.— Continued.

a WATERIN PLANTS | @
as oo
o4 fy 2
nea oo
NAME as b I
4 fo a
By % & ae

z

=k F a | Ba

a Qa Bi z
Elymus virginicus L...........0. 0... 5.6 283T Weuiseuis late 1
Erigeron ramosus (Walt.) B.S. P...... 71 20:2 laxaioabien » 2
Eupatorium ageratoides L.. ........... 6.5 23.0: jxamwam ass 1
Eragrostis purshii Schrad.............. 7.6 16.0 80.0 1
Buphorkia dentata Michx.............. 10.7 80:0. | Wrditucsrir ae 1
Euphorbia marginata Pursh........... 5.8 B90 Pesce vies « 3
Euphorbia obtusata Pursh.............. 6.3 SOE Wosetecsid aaa 1
Fragaria virginina Duchesne.... .......] 6.4 23.1 77.0 2
Faleata comosa (L.) Kuntze............ 6.9 BOnd- [seein caase 1
Galium aparine L..............-..0065 10.6 42.6 72.1 4
Gaura biennis L..... ...........- ceeeed 5.9 31.8 84.1 9
Gaura parviflora Dougl................ 6.5 30.6 80.0 7
Geum canadense Jacq.. ............0005 80 Pe a Pere 7
Grindelia squarrosa (Pursh.) Dunal... .| 6.8 45.9 83.8 6
Helianthus annuus L. var. ?........... 6.4 28.2 80.6 4
Helianthus annuus L.. ...... ........ 6.5 36.5 89.9 19
Helianthus rigidus Desf................ 8.3? | 20.0 88.0 a
Hordeum jubatum L....... eee 6.7 28.7 85.5 10
Hordeum vulgare L........... 0.22... 6.8 87.5 90.0 27
Ipomoea purpurea Roth............... 4.1 Cel an erence 2
Iva frutescens L. 2.1... ee eee 7.0 44.7 61.5? 10
Laciniaia scariosa (L.) Hill .. ........ 9.0?} 498 |..... 0... 1
Lactuca sativa L.. 2.2... eee eee eee 8.5 27.5 92.0 6
Lactuca seariola L. ...............000- 9.6 44.2 88.2 9
Lactuca pulchella (Pursh.) D.C.... ...] 9.0 oe re 2
Lepachys columnaris (Pursh.) T. &G..| 7.2 39.2 70.0 3
Lepidium apetalum Willd......... .... 68 27.8 76.5 7
Leptilum canadense (L ) Britton........] 6.6 26.38. |eecencres 6
Lobelia syphilitica L...... 2.0... cee ee 10.3 30.0 86.0 9
Lotus americanus (Nutt.) Bisch........ 9.62} 20.0 |......... 2
Lycopersicum eseulentum Mill......... 5.3 > a era 1
onarda fistulosa L............6. 2. eee 6.7 34.9 82.6 4
Nasturtium officinale R. Br............ 3.7 33.4 91.3 7
Nicotiana tabacum L...... .. ......0. 4.6 BL.0 Leeeveees 1
Onagra biennis (L.) Scop...........6005 6.9 35.6 82.0 9
Oryza Sativarli, sussa cues 5 oeuea sa sews 7.0 18.9 62.5? 9
Oxalis stricta L............ 0. cece eee 6.2 40.0 81.3 12
Panicum capillare L................005 8.27] 838 |......... 1
Panicum crus-galli L.............-005- 7.2 35.6 76.0 18
Panicum proliferum Lam......... .... 78 39.4 85.0 3
Panicum scribnerianum Nash.......... 7.8 27.7 83.9 2
Panicum virgatum L..............0000- 6.8 28.0) leveessaas 4
Panicum walteri Pursh................ 8.7 27.2 81.4 4
Pastinaca sativa L.......... cee eee eee 4.3? | dead |......... 1
Penstemon cobaea Nutt............00. 8.83 | 32.2 3

SPECIES LISTS—NON-AVAILABLE WATER 73

LIST OF SPECIES.—Concluded.

fa WATER IN PLANTS \
oR Bo
ed Bg
NAME fs 5 y eo
as g 5 ES
g z, a) 4 Sa
BE A fl zZ
Phaseolus vulgaris L ...............00. 7.9 44.1 90.4 36
Physalis heterophylla L................ 6.8 Oi Sa eee 1
Physalis virginiana Mill............... 8.8 ALB bcicamee 2
Pisum sativum L.................. .| 74 43.7 89.8 10
Plantago elongata Pursh... .......... 58 22H cmateacendts B
Plantago major L...................00 V7 25 8 88.5 3
Plantago purshii R. & S.......... sets | SD +1 Gt a ere ee 1
Plantago rugelii Dec................... 0.9 27.0 84.0 13
Poa pratensis Dens ccc scccwas coe ceed vis 6.9 B97 beware eee 5
Potamogeton lonchites................. 24.8 32.8 86.9 1
Portulaca oleracea L. ................. 8.62 GIO ts snisyorecda » 3
Potentilla arguta Pursh ............... 8.4 31.3 78.8 3
Potentilla monspeliensis L............. 7.3 29.1 71.4 4
Psoralea floribunda Nutt............... 7.3 48.3 83.8 1
Quercus macrocarpa Michx............ 6.6 18.9 75.5 1
Ranunculus abortivus L................ 6.5 26 1 87.1 4
Ranunculus sceleratus L............... 10.5 57.1 89.3 2
Raphanus sativus L........ ........... 6.9 39.2 93.5 19
Ricinus communis L................ 4. 65 21.3 84.8 5
Roripa sinuata (Nutt.) Hitchcock....... 8.9 BB.2 0 |... ee. 2
Rumex acetosella L................... 66 34.8 80.6 8
Rumex ecrispus: lows i dice cewrea sete v 08s 8.3 35 4 80.8 11
Sagittaria latifolia Willd............... 15.6 44.6 93.2 4
Secale cereale L. 1... 1 eee e eee ee ee eee 6.1 27.6 83.3 2
Sium cicutifolium J. F. Gmel........... 8.7 40.9) Ji........ 4
Solanum nigrum L....... ............ 5.6 QB |sceapeaueres 5
Sonchus arvensis L .................465 5.1 HES”. Nkhaemernn « 5
Sporobolus longifolium (Torr.) Wood..| 5.8 20 9 65.2? 5
Sporobolus vaginiflorus (Torr.) Vasey..| 4.4 AB ees aad 4
Steironema ciliatum (L.) Raf .......... 7.9 25.7 80.2 2
Strophostyles helvola (J..) Britton...... 5.1 a a eee re ee 1
Syntherisma sanguinalis (L.) Nash..... 6.6 37.3 81.5 38
Thalictrum purpurascens L............ 8.1 BAM! is scggiatideiers 2
Thelesperma gracile (Torr.)...... ..... 6.7 48.3 |... 3
Trifolium pratense L................4. 5.8 8056 lasewmeies 2
Trifolium repens L.................065 8.11 | 20.4 73.2 2
Triticum vulgare Vill.................. 6.0 24.4 80.5 10
Verbena bracteosa Michx.............. 6.7 SlsO™ | aan ektrs 1
Verbena hastata L. ............2..0085 6.5 19.5 [osessedas 38
Verbena stricta Vent.................- 6.8 29:6 la scamea-ss 8
Verbena urticifolia L.. ............... 6.97? | 24.0 J......... 4
Vernonia baldwinii Torr............... 6.0 Die Ke! Ulloa stones 3
Vicia taba Liss. ucsecgen tem aeeesan eta o 7.0 82.4 90.5 5
Viola obliqua Hill..................004. 8.9 59.7 82.5 1
Viola pedatifida Don ..... .......... 7.5 12.9 80.0 1
Viola scabriuscula (T. & G.) Schwein... | 9.0 2687 ls siacaunsen’y s 5
Zea mays L. (sugar corn).............> 6.0 58.7 90.7 3
Zea mays L. (yellow dent)............. 5.9 39.0 89.1 27
743

74

STUDIES IN THE VEGETATION OF THE STATE

LIST OF SPECIES.
(List obtained from plants in fields about Lincoln during

a dry period, August, 1900.)

VATIONS

fy

LIMIT OF PHYSIOLOGICAL WATER 6

SPECIES aa

. : °

os, | Boke | sauine | char 2 &

Amaranthus graecizans.......... 60 dhiaswese devs caemeliassas- 4
A. retroflexus...........6.0-000% BiG | | ecwaaind versa tasldeion ees 4
Atriplex argentea................ 5.0 |......0. T4D) enscc seeds 7
Chaetochloa viridis............. 5.6 BL08 Ul uses Seieey 5.7 12
Chaetochloa italica.............. DiS: lsernadamsla saveeenfieowuce ad 4
Chenopodium album............ Bl [vases eeten/ secs eal aie ave 4
Distichlis spicata.............-..).....006 DG. faececarn seeps anaiieuapave 2
Eragrostis major ............... 5.0 OHO i sredetngs | ta aii 1
kuphorbia maculata............- 5.3 60° loses eis] eecevers 4
HonUlansc.ciatuiraee se esata: Eel abies eee 6.0 lsavawace|as voces 1
Ey S@rpens saseeccereieres cy sass 5.8 $6 | asnewssllose ana 5
Grindelia squarrosa .............]. soot] BLO [asa sesitcoe alll eae ccare 2
Helianthus annuus............... 56 7.6 D6 Ae Pe saccns 9
Leptilum canadense.............]........ ann peeeeiieeee reeperes 1
OXAlis Strict. icc. cece connie d | ewer ives G08 bes searecaua its fovet wage 1
Panicum capillare............... 6.0 O22) i) Genel maes 6
Pe CPUS “Ca cacecca-5.ssarssneveonnvescinarers’|anadwrans Got ewiesesiag | ie gcteces 6
Po VAT Batu. cdcewassvgde onde wae B.6) vcs cs ienl eesoats ids lwe sales 1
Pod, pratensis... cue ee de san geen g wigaedlve cs ee dl vada ba 9.5? 2
Polygonum aviculare............|.......- 5.0 las esa velvavenes 4
P. Cam pOruiiw:.«:.c'.csanseneuat sdllasuauaislleee ax acd 16:4: sexes s 1
Portulaca oleracea...............)...00008 8:8 [eens tapenade. 2
Sorghum vulgare... ............ 6.1 Gel | bass pede |taacneas 3
Syntherisma sanguinalis,. ......]........ Glendora oreimahenbiaeiore 6 9
Verbena hastata.............-..-]occe eee DG |raseiges|sseons'e 1
Total observations from field... 102
Total observations from planthouse.... 743
LOtal ooci casos divans Sule eet soesene 845

SPECIES LISTS—NON-AVAILABLE WATER 75

EXPLANATION OF THE DATA IN THE FOLLOWING
SPECIES SHEETS AND COMPARATIVE PLOTS.

1. “Date.’? This is the date of final weighing of the
plant, wilting or dead.

2. ‘‘Locality,’’?Under sub-heading ‘‘A’’ is the locality
where the plant was grown.

Under “B”’ the locality where the drying took
place.

The following abbreviations are used for different
localities where plants were grown:

“P.-H.’’? Normal conditions, Plant House.

“P.-I.’ Wet, Shade, es a

“Pp.-II.’’ Dry, Shade, ”’ a2 2

“P.-IIL’’? Wet, Sun, ad 3

“Pp.-IV.”? Dry, Sun, es

“C.-I.’? Cool plant case.

“©.-IL.”’? Shade, ” a

“C.-IIL.’’? Normal, ” a

“C.-IV.”’ Humus, ” a

‘‘hiab.’? Xerophytic conditions, laboratory.

3. “Plant Stage’’ is the stage of growth of the plant
at the time the period of drying began. ‘‘Ros.’’ in-
dicates the rosette stage, ‘‘Fl’’ the flowering stage,
and “St.’? the stem forming period, while ‘‘Sdl.”
indicates the immature seedling condition.

4 “Time’’. This column gives the number of days it
took the plant to reach the limit of available soil
waiter.

5. “Soil Water.’’? Under ‘‘a’’ of this heading is the
per cent of availale water in the soil, and under‘‘b’’
is the per cent of non-available water in the soil.

6. ‘‘Plant Water.’’ In column ‘‘a’’ is the per cent of
water in the plant at or near the limit of available
water. In column ‘‘b’’ is the per cent of water in a
healthy plant of about the same age grown under
similar conditions.

7. The letter ‘‘e’’? placed before a per cent indicates
that the per cent was not determined by weight, but
by estimation.

76 STUDIES IN THE VEGETATION OF THE STATE
SPECIES SHEETS.

Phaseolus vulgaris L.

LOOALITY SOIL SOIL WATER | PLANT WATER
PLANT| TIME
DATE STAGE | DYING
a b a b a b a b
4-26. | P-H. | P-H. | Loe. | Ls. | Sdl. |26 da. 4.8 6.3 | 17.6 |e90.4
4-29, ve ie “ ce = 28 * 6.8 5.3 | 26.92 | 90.4
4-22. ad or Lm. uf ue Q1 8 3.4 6.7 | 29.2 | 904
4-27. e ve = us ic 26 * 4.3 58/853 | 90.4
4-26. os nis Sd. .P oe 25 * 2.3 0.5 | 14.8 | 90.4
4-29. " mt es a os 28 * 2.3 0.4 | 44.8 | 90.4
COMPARATIVE PLOT II.

5- 6. |C-I. |C-I. | Loe. | Ls. | Sdl. |26 da.| 12.3; 88 | 56.3 |e90.4
4-30. |C-IL. |C-IT. ai ee 120 =‘ 6.1] 13.8 | 54.6 | 92.3
4-26. |C-IIL.|C-II1. - ~ eo HG 9 ee 14.4 8.5 | 39.7 | 90.4
4-23. |C-IV. |C-IV. ee My Me TG: 138| 12.0 | 63.6 | 92.3
4.26. | Lab. | Lab. ne se oe VLE “ES 4.2 7.9 | 55.7 | 87.2
5- 9. |C-I. |C-1. Lm. Ls. | Sdl. |29 da.| 15.2 9.1 | 70.0 {290.4
5: 4. JC-II. |C-IL. es = ss 24 ‘* 10.0] 12.3) 65.0 | 93.2
4-26. |C-ILL. |C-IIL * a et 16“ 131 8.9 | 86.4 | 92.0
4-27. |C-IV. |C-IV ne ae s 26 “| 20.38} 111] 716 | 92.44
5- 4. | Lab. | Lab ae ate = 24 “ 6.3 9.1) 74.2 | 90.0
5- 3 IC-I. [C-L. Sd. Ls. Sdl. /23 da.) 3.1 0.3 | 12.0 /e90.4
5- 1. JC-IL. |C-IT vk " - a1: “8 4.2 0.3 | 60.7 | 93.2
4.26. |C-1IL. |C-III. " ne aN 16“ 5.3 0.4 8.7 | 92.0
4.30. |C-IV. |C-IV. i is ee i9 * 5.7 0.5 | 46.3 | 88.9
4.29. | Lab. | Lab. - ee a 138° 2.3 0.5 | 48.8 ba

SPECIES SHEETS

Hordeum vulgare L,

77

LOCALITY SOIL SOIL WATER |PLANT WATER

DATE PLANT | TIMB
STAGE | DYING

a b a b a b a bd
5- 9. 1C-I. |C-L. Loe.} Ls. | Sdl. {29 da.| 7.6 | 8.9 | 21.5 | 79.72
4-24. |C-II. |C-II. Me ae * 8 “ | 8.1 | 11.9 | 8.3 |e85.0
4-30. |C-1II. |C-IIL. |“ . “414 “ | 4.6 | 7.8 | 52.0 | 88.8
5- 6. |C-IV. |C-IV. | « ue se 726 | 9.2 | 9.2 | 81.5 | 86.1
4.29. | Lab. | Lab. |‘ m © /138 "| 9.2 | 9.0 | 80.5 | 91.3
5- 9.)C-I. |C-I. |Lm. | Ls. | Sdl. |29 da.| 11.1 | 6.0 | 81.4 | 83.0
4.27. |C-II. |C-II. ~ ns i pe 4.0 | 16.6 | 11.5 |e85.0
4-30. |C-IIL. |C-IlI.| ‘ ‘ “114 “| 8.0 | 9.9 | 49.0 | 90.8
5 -6. |C-IV. |C-IV.| “ i 126“ | 12.0 9.9 | 32.2 | 86.4
4-29. | Lab. | Lab. os ss «1138 ** | 11.9 7.4 | 47.9 | 91.8
4-30. |C-I. |C-1. Sd. Ls. | Sdl. /14 da.) 2.9 0.22| 26.0 | 91.5
4-24. |C-1I. |C-I. ce ae ai 8 “| 10] 05 | 6.8 |e85.
4-25. |C-1II. |C-IIL.| ‘* i a 9 | 5.5 | 0.2 | 5.2 | 87.5
5. 1. |C-IV. |C-IV. | “ ae ce 21 | 6.0 | 0.2 | 20.8 | 88.1
4-30. | Lab. | Lab. | “ oy “114 | 2.6 | 0.46) 47.7 | 91.8

Zea mays L. (Yellow Dent Corn.).
(COMPARATIVE PLOT II.)

LOCALITY SO1L SOIL WATER |PLANT WATER

DATE PLANT | TIME :
STAGE | DYING

a b a bd a b a b
4.27.| P-H. | P-H. | Loe. | Ls. | Sdl. |16 da.} 6.5 | 4.6 | 34.9 | 93.3
6-26. |“ = ‘ “715 6.3 4.8 | 33.0 | 93.3
4.29. |C-I, |C-LI. He “ Be EQ 9.0 90 | 43.3 | 78.7?
4-30. |C-II. |C-IL. ae sf “120 “ | 6.0 | 11.8 | 60.3 | 92.4
4-30. |C-III. |C-L1I. |‘ “ “120 «| 16.4 | 65 | 48.4 | 90.4
5- 8. |C-IV. |C-IV. * ig 123 | 12.6 7.1 | 57.9 } 90.8
4-27. |Lab. |Lab. ts SS “117 “| 9.8 | 8.8 | 41.4 | 92.38
4-27.| P-H. | P-H. | Lm. | Ls. | Sdl |16 da.} 7.0 | 3.1 | 11.8 | 933
4.27.1 + ie m we « 116 * 5.9 4.2 | 47.3 | 933
5-9. |C-L. |C-I. ae “ 129 | 16.7 ) 7.6 | 41.5 | 84.7
4-30. |C-1I. |C-II. x ee «120 | 9.2 | 12.7 | 50.4 | 95.4
4.29. |C-II1. |C-III. | ‘“ e «119 «| 14.6 | 6.1 | 48.2 | 92.0
5- 3. |C-1V. |C-IV a “123 | 12.6 | 8.8 | 59.9 | 91.9
4-27. |Lab. |Lab. ee ee “117, | 8.5 | 7.2 | 89.1 | 91.8
4-30. | P-H. | P-H. | Sd. Ls. | Sdl. |29 da.| 3.8 | 0.6 | 562.8 | 93.3
4-30. |“ of ae a «129 | 3.8 | 0.6 | 86.8 | 93.3
4-25. |C-I. |C-I. He ae “116 “ | 2.8 | 0.45) 36.3 | 80.4
4-26. |C-II. |C-II. o a “« 116 “| 56 | 0.1 | 53.3 | 89.7
4-27. |C-III. |C-IIl. | * a clay s6 | 5.8 | 0.4 | 22.5 | 81.7
5- 1, |C-IV. |C-IV a es «21 | 5.9 | 0.3 | 42.2 | 85.2
5- 2. Lab. [Lab. se ee ie 192) Sb AT 0.3 | 29.5 | 91.3

78 STUDIES IN THE VEGETATION OF THE STATE

COMPARATIVE PLOT NO. III.

Sand.

HEALTHY PL’T | WILTING PL'NT| DYING PLANT
TIME IN
PLANTS DYING

SOIL |PLANT SOIL |PLANT SOIL |PLANC
Phaseolus............ 13 da. 8.3 | 90.4 0.42 | 78.0 | 0.26 | 38.8
Helianthus.......... 9“ 8.7 | 94.7 0.41 | 78.8 | 0.2 44.9
Hordeum. .......... ie 11.9 | 89.2 0.41 | 70.0 | 0.81 | 53.0
Ricinus............6- 16“ 11.5 | 854 0.5 63.2 | 0.44 | 24.3
LAO Diss occdnieseracwia ik tie Eo 129 | 93.0 0.4 72.2 | 0.41 | 58.2
Average ...... 0.045. 15‘ 10.6 | 90.5 0.43 «| 72.4 ' 0.382 | 48.8

Loam
Phaseolus. .......... 17 da. 24.4 | 90.1 |10.6 805 | 8&7 53.0
Helianthus .......... yt 23.8 | 922 |11.6 87.6 | 11.2 61.4
Hordeum... ......... 18.“ 29.7 | 913 9.8 52.0 | 8.7 39.4
RICIMUB ais cogeieerdicccuss 1 237 | 84.4 | 10.3 82.5 | 91 610
Li iss otras — eaves eavaecians 12 “ 24.9 | 93.0 | 12.5 81.7 | 101 60.4
Average ...... ..+-+ 1a * 25.3 | 90.2 | 10.9 76.8 | 9.5 54.8

Saline
Phaseolus............ 17 da. 28.9 | 90.0 |17.2 800 | 19.8 53.7
Helianthus.......... i ™ 26.3 | 986 |151 85.4 | 12.7 59.0
Hordeum....... .... 19 “ 29.5 | 838.4 98 82.2 |119 53.4
Ricinus.............. a 28.4 | 844 | 12.0 76.5 | 12.4 60.0
LRB, o 6 deed dese newer 12 ** 20.5 | 920 {168 83.4 | 13.8 61.0
Average ............ 14 “ 24.7 | 88.7 | 14.2 81.5 | 14.0 57.4

Clay.
Phaseolus............ 13 da. 169 | 89.5 8.5 78.9 | 85 61.8
Helianthus... ........ 9 Fa 21.0 | 87.6 9.1 84.9 | 9.3 60 3
Hordeum ........... 14 “ 18.2 | 938.3 6.4 69.3 | 7.1 42.2
Ricinus.............. Ad: 20.0 | 84.4 9.2 80.6 | 10.3 65.9
BS bc usesate ee Reso iy is 16.4 | 92.0 9.4 75.0 | 7.9 48.0
Average............. 12 «* 18.5 | 89.4 8.5 77.7 | 8.6 61.7

Loess
Phaseolus ..... ..... 17 da. 12.4 | 89.6 8.4 85.6 | 8.7 52 3
Helianthus .......... Ti, 18.0 | 93.9 |10.9 815 | 10.3 55.2
Hordeum............ LR & 187 | 864 8.1 94) 71 50.1
Ricinus.............. 10 “ 24.7 | 84.4 7.8 74.3 | 10.9 48.6
CAsccuae Kae tele es 12" 199 | 920 |13.1 82.4 | 9.3 56.1
AVELALO. ees 2888 18“ 18.7 | 89.3 |10.1 80.9 | 92 52.7

_ Hummus
Phaseolus ........... 17 da. 19.0 | 900 9.3 81.0 | 11.0 32.1
Helianthus...... ... a 25.38 | 90.2 | 11.5 79.2 {11.8 59.7
Hordeum........ ... 17“ 28.9 | 88.8 | 11.3 69.1 | 9.8 30.6
Ricinus.......... ... 10 ‘' 24.7 | 84.4 112.1 79.7 | 12.8 61.9
LOS ss i awaa aeaans ve li ‘“ 29.1 | 92.0 | 11.9 63.5 | 9.1 58.0
Average............. 13 25.4 | 89.1 | 11.2 74.5 | 10.7 48.4

SPECIES SHEETS

MECHANICAL ANALYSIS OF SOILS.

79

By Mr. A. T. Wiancko, Assistant Agriculturist, Agricultural
Experiment Station, University of Nebraska.

soIL SOIL SOIL SOIL SOIL som
No.1 No, 2 NO. 3 No. 4 no, 5 Nv.6
INGREDIENTS

SAND LOAM SALINE CLAY LoEss | HUMUS
Coarse Gravel....| 18.85 | 0.20 O67 Voossasmas 1.27 3.88
Fine Gravel ...... 18.04 1.82 1.35 0.77 1.23 7.58
Coarse Sand...... 21.46 | 3.12 2.08 1.62 1.76 8.84
Medium Sand ....| 3644] 7.30 3.60 2.88 7.18 18.30
Fine Sand........ 5.92 | 1.24 8.26 0.76 9.63 7.27
Very Fine Sand...| 2.88 | 9.06 14.53 10.88 15.98 13.00
Silbcs secre v sence ba 0.34 | 50.21 27.12 28 09 24.13 17.37
Fine Silt.......... 0.15 | 11.18 20.47 7.96 24.16 10.65
Cla Viste ings tels'é'e's 0.08 | 9.34 20.68 39.92 15.10 4.82
Water*........... 0.60 | 3.20 2.92 2.80 2.91 2.03
Volatile Matter...) 0.383 | 8.2 4,12 4.58 2.80 14.42
Loss or Gainf..... -0.51 | -1.62 $2.62 -1.94 73.24 71.138
Soluble Salts ..... ceeeeeee| 0.1519 0.5092 0.1574 0.1282 | 0.2193

*Water in air dry soil.

toss or gain in handling.

THE DEVELOPMENT AND STRUCTURE
OF VEGETATION

THE WOODRUFF-COLLINS PRINTING COMPANY.
LINCOLN, NEBRASKA.

THE DEVELOPMENT AND STRUCTURE OF
VEGETATION.*

FREDERIC EH. CLEMENTS.

Vegetation exhibits certain phenomena which are char-
acteristic manifestations of the forces which lie at its found-
ation. Such phenomena are peculiar to it, and are entirely
distinct from those primary activities of the individual that
are termed functions. This conception will be clearer if we
consider vegetation as an entity, the changes and structures
of which are in accord with certain basal principles in much
the same fashion that the functions and structures of plants
correspond to definite laws. But the fundamental phe-
nomena of plants as individuals, and of plants united ina
complex termed vegetation are altogether different concepts.
Thus, functions are properties of individuals, and are funda-
mental for them alone. They are rhythmic or progressive
changes in the individual, and are characteristic of vege-
tation only in as much as it is a complex of such indi-

*Read before the Botanical Society of America at the Denver
meeting, August 1901.

Nots. The principles here enunciated constitute at once the work-
ing basis and the conclusions of a special investigation into the phy-
logeny and structure of vegetation begun in 1897. These studies have
been pursued in the grassland and woodland formations of Nebraska,
and throughout the formations of the Rocky Mountains of Colorado.
Certain of these principles, association, invasion and zonation, have
long been recognized, but no systematic consideration of them has
been attempted heretofore. The principle of succession is more recent,
and is not so well developed, while alternation is herein defined and
analysed for the first time (Cfr. note, Rep. Bot. Surv. Nebr. 5:55 1901).
These principles were first formulated in their present relation early
in 1898 as working hypotheses, and have been subjected to constant
test in the field since that time. Their confirmation has been repeated
and conclusive, and they are now submitted as a definite and logical
basis for research in the development and structure of vegetation.
The present paper is intended to constitute the general portion of a
detailed report dealing with the physical factors of the prairie for-
mation in Nebraska, and with the structural expression of such factors.
The special portion will appear in a later report of the Survey, while
the application of the principles to mountain formations will be made
in a forthcoming volume upon the vegetation of the Rocky Mountains
of Colorado.

6 DEVELOPMENT AND STRUCTURE OF VEGETATION

viduals. Tho latter exhibits within itself peculiar changes,
likewise rhythmic and progressive. These changes consti-
tute or produce the fundamental phenomena of vegetation.

From the nature of this primary dependence upon envir-
onment, vegetation is essentially dynamic, but, on account
of its marked reaction upon the habitat, it exhibits a con-
stant tendency to become static. Its characteristic phe-
nomena, then, are manifestations of change, in which each
successive stage is less dynamic and correspondingly more
static. The physical and biological factors which constitute
a habitat are so diverse and their interaction so complicated
that complete stasis is never attained, though forest and
grassland sometimes closely approximate this condition.
Even in such formations, however, the facies alone are
static, the subordinate species being in constant readjust-
ment to slowly intensifying conditions. Furthermore, in all
formations, whether they have attained a degree of stasis
by progressive changes or not, there is still a seasonal
rhythm of appearance, reproduction and decadence, which
remains always and essentially dynamic. Finally, the phe-
nomena of vegetation illustrate this primary distinction be-
tween the dynamic and the static. Invasion and succession
are completely dynamic in their operation, i. e., develop-
mental, while association, zonation and alternation are re-
latively static, i. e., structural. The further consideration
of the dynamics of vegetation will, in consequence, be found
under invasion, and, especially, under succession.

The fundamental phenomena of vegetation are associ-
ation, invasion, succession, zonation and alternation. Of
these, association represents the stage to which vegetation
has been brought by the cumulative changes of the past.
It corresponds essentially to the historical fact in vege-
tation. Invasion and succession are dynamic forces ro phe-
nomena which are at work modifying the present facts of
association. They are initiated by physical factors, and are
wrought out by the interaction of physical and biological
factors. Hence, they are representative of the physical fact

INTRODUCTION va

in vegetation. Zonation and alternation, on the other hand,
are static phenomena, characteristic of the vegetative cover-
ing as it is and will be when it becomes more and more
static. Thus, the relation of plants to the surface of the
globe finds its basal expression in the one great principle or
phenomenon of association, for which indeed vegetation is
but another name. In its dynamic aspect, developmentally,
association is controlled by two laws, that of invasion and of
succession, while in its static aspect, structurally, it con-
forms to the laws of zonation and of alternation.

In the analysis of vegetation. it is imperative that the
twofold nature of its origin be kept clearly in mind. Just
as a species of today is the result of accumulated ancestral
facts modified to a certain degree by existing physical
factors, so a particular vegetation of the present time, indeed
all vegetation, is the result of a complex physical fact, the
habitat or environment, acting upon a biological or histor-
ical fact, the antecedent vegetation. Since the basis of
vegetation is twofold, physical and historical, the principles
manifested in it must correspond to the one or the other.

ln the following treatment, the fundamental facts of vege-
tation are considered separately in a somewhat detailed and
systematic manner. The arrangement under each is the
same. The conception of each principle and its relation to
the others are first discussed; then the consideration of
causes, categories. manifestations and results follows in the
logical order. A shori statement of the historical develop-
ment of each subject is given in the proper place. Because
of its bearing upon the origin and modification of formations,
the neglected doctrine, polyphylesis, is considered in con-
nection with invasion.

ASSOCIATION

The principle of association is the fundamental law of
vegetation. Indeed, association is vegetation, for the indi-
vidual passes into vegetation, strictly speaking, at the
moment when other individuals of the same kind or of
different kinds become grouped with it. It is then (and the
same statement necessarily holds for vegetation) the coming
together and the staying together of individuals and, ulti-
mately, of species. A concrete instance will illustrate this
fact. In the development of the blowout formation of the
Nebraska sandhills (Redfieldia-Muhlenbergia-anemodium), as-
sociation begins only when the first plant of Redfieldia fea-
uosa is joined by other plants that have sprung from it, or
have wandered in over the margin of the blowout. Hence-
forth, however dynamic the blowout may remain, or how-
ever static it may become, association is a settled character-
istic of it until some new and overwhelming physical cat-
astrophe shall destroy the associated individuals. It will
readily be seen that association does not depend upon par-
ticular individuals, for these pass and others take their
place, but that it does depend essentially upon number of
individuals.

Association involves the idea of the relation of
plants to the soil, as well as that of plants to each other.
It is synonymous with vegetation only when the two re-
lations are represented, since there may be association such
as that of a parasite with its host, which does not constitute
vegetation. But it will be seen that the relation of the para-
site to the host is practically identical with the relation of
the plant to the soil or stratum, and the two concepts men-
tioned above become merged. From this it follows that
association results in vegetation only when the two ideas
are distinct. The concept of association contains a fact that
is everywhere significant of vegetation, namely, the likeness
or unlikeness of the individuals which are associated. In
the case of parasite and host, this unlikeness is marked; in
vegetation, all degrees of similarity obtain. As will be evi-
dent when the causes which lead to association are con-

10 ASSOCIATION

sidered, alternate similarity and dissimilarity of the consti-
tuent individuals or species is subordinate asa feature of
vegetation only to the primary fact of association.

In considering the causes which produce association, it is
necessary to callin evidence the primary facts of the ontogeny
of concrete examples of the working of this principle. These
facts are so bound upin the nature of vegetal organisms
that they are the veriest axioms. Reproduction gives rise
immediately to potential, and ultimately, in the great major-
ity of cases, to actual association. The degree and perman-
ence of the association are then determined by the immobility
of the individuals as expressed in terms of attachment to
each other or to the stratum, such as sheath, thallus, haus-
toria, huldfasts, rhizoids, roots, etc. The range of immob-
ility is very great. In terrestial plants, mobility is confined
almost entirely to the period when the individual lies dor-
mant in the seed, spore or propagative part, which is alone
mobile. In aquatic spermatophytes, the same is true of all
attached forms, while free floating plants such as Lemna are
mobile ina high degree, especially during the vegetative
period. Among the algae and hydrophilous fungi, attached
forms are mobile only in the spore or propagative condition,
while the motile forms of the plancton typify the extreme
development of mobility. The immediate result of repro-
duction in an immobile species is to produce association of
like individuals, while in the case of a mobile species repro-
duction may or may not lead immediately to association.
We may lay down the general principle that immobility
tends to maintain the association of the individuals of the
same generation, i. e., the association of like forms, while
mobilty tends to separate the similar individuals of one
generation and to bring unlike forms together. With the
mobile algae, separation of the members of each generation
is the rule, unless the individuals come to be associated in a
thallus, or are grouped in contact with the substratum.
Flowering plants that are relatively immobile, especially in
the seed state, drop their seeds beneath and about the
parent plants, and in consequence dense association of the

CAUSES 11

new plants is the rule. In very many cases, however, this
primitive tendency is largely or completely negatived by the
presence of special dissemination contrivances, which are
nearly, if not quite, as effective for many terrestrial plants,
as the free floating habit is for algae. From this point, the
whole question of mobility belongs to migration, just as the
adjustment between the parent plants and their offspring,
or between plants established and the mobile plants to be
established belongs to occupation.

If association were determined by reproduction and im-
mobility alone, it would exhibit areas dissimilar in the mass
of individuals, as well as areas dissimilar in the kinds of in-
dividuals. Some areas would be occupied by plants of a
single species, others by plants of several or many species.
This tendency of association to show differences is, however,
greatly emphasized by the fact that vegetation is funda-
mentally attached to and dependent upon a surface that ex-
hibits the most extreme physical differences. For this
reason, new differences in association appear, due not only
to the morphological differentiation of vegetation forms, but
also to the changes in the degree and manner of association
produced directly by the different habitats. Association
might then be defined asa grouping together of plant in-
dividuals, of parents and progeny, which is initiated by re-
production and immobility, and determined by environment.
It isa resultant of differences and similarities. In conse-
quence, association in its largest expression, vegetation, is
essentially heterogeneous, while in those areas which possess
physical or biological definiteness, habitats and vegetation
centers, it is relatively homogeneous. This fundamental
peculiarity has given us the concept of the formation, an
area of vegetation, or a particular association, which is
homogeneous within itself, and at the same time essentially
different from contiguous areas, though falling into a phy-
logenetic series with some and a biological series with
others. From its nature, the plant formation is to be con-
sidered the logical unit of vegetation, though it is not, of
course, the simplest example of association.

12 ASSOCIATION

The term formation was proposed by Grisebach in 1838;
he defined the concept as follows: ‘‘Ich méchte eine Gruppe
von Pflanzen, die einen abgeschlossenen physiognomischen
Charakter traegt. wie eine Wiese, ein Wald, etc., eine pfian-
zengeographische Formation nennen. Sie wird bald durch
eine einzige gesellige Art, bald durch einen Complex von
vorherrschenden Arten derselben Familie charakterisiert,
bald zeigt sie ein Aggregat von Arten, die, mannigfaltig
in ihrer Organisation, doch eine gemeinsame Higenthuem-
lichkeit haben, wie die Alpentriften fast nur aus perennier-
enden Kriautern bestehen.’’ Before Grisebach’s time,
several writers had perceived the essential correspondence
between habitat and vegetation, though they did not recog-
nize the fundamental importance of this relation. Linné
mentioned a few generalized stations in Flora Lapponica (1787)
and Flora Suecica (1745), but in the Philosophia Botanica (1751:
265) be not only distinguished the following twenty-five hab-
itats, but also characterised each briefly and listed the prin-
cipal genera: mare, littora, fontes, fluvii, ripae, lacus, stagna,
paludes, cespitosae, inundata, uliginosa, alpes, rupes, montes,
campi, sylvae, nemora, prata (a. fertilia, b. exsucca, c.
humidiuscula), pascua, arva, agri, versurae, culta, fimeta,
ruderatae, In addition, he arranged stations in four groups
with respect to the kind of soil, viz., humus, arena, (mobilis,
farinacea, vulgaris, sabulosa), argilla, creta.

Hedenbere ({754:73) recognized twenty-four stations,
naming them after the specific names of characteristic
species, and classifying them in five groups as follows:
Aquaticae; (1) Marinae (2) Maritimae (8) Lacustres (4)
Palustres (5) Inundatae (6) Uliginosae (7) Caespitosae;
Alpinae, (8) Aetherea (9) Occlusae; Umbrosae, (10) Nemo-
rosae (11) Sylvaticae; Campestres, (12) Arvenses (13)
Cultae (14) Ruderales (15) Pratenses (16) Arenariae (17)
Argillaceae (18) Cretaceae; Montanae, (19) Glabretosae
(20) Collinae (21) Rupestres; Parasiticae (22) Arboreae
(23) Herbaeeae (24) Radicales. Each station is described
briefly, and the vegetation usually characterised in a few
words, e. g.,;‘‘10. Nemorosae. Loca Nemorum sub arboribus

THE FORMATION 13

frondosis, humo laxa, frondibus per hyemem tecta, aestate
foliis obumbrata. Plantae fragiles, florentes vere ante
frondescentiam.’’ Finally, the species of the Swedish flora
are grouped under their proper stations.

Humboldt (807:57) recognized formations only in-
cidentally, as in the following: ‘‘Les bruyéres, cette
association de V’erica vulgaris, de Verica tetralix, des lichen
temadophila et haematomma se répandent depuis l’éxtremité
ja plus septentrionale du Jutland, par le Holstein et le Lune-
bourg jusqu’au 52 degré de latitude.’? Mirbel (1815 :583)
in his monumental Terminologie Methodique, characterised
briefly forty-two stations, indicating a few typical species in
each, and grouped them as follows: Terrestres, arenariae,
saxatiles, ruderales, argillosae, cretaceae, graniticae.
oleraceae, hortenses, vineales, agrestes, arvenses, pratenses,
sylvaticae, umbrosae, campestres, collinae, montanae
(alpestres, alpinae), glaciales, hyperboreae, salinae, littor-
ales, maritimae; Aquaticae, marinae, lacustres, fontinales,
fluviatiles, submersae, emersae, fluitantes, natantes, pal-
ustres, uliginosae, torfaceae; Amphibiae; Epiphytae; Para-
siticae, epirhizae, corticales, epixyloneae, epiphyllae; Sub-
terraneae, interraneae, cavernariae. That De Candolle (1820:
25, 29) clearly understood the importance of stations is
shown by his statement: ‘‘L’étude des stations est, pour
ainsi dire, la topographie, et celle des habitations la géo-
graphie botanique,’’ and also by his classes of stations.
Schouw (1824:153) proposed an arrangement of stations that
was far in advance of his time, and exhibits much of funda-
mental value at the present time. He was the first to dis-
tinguish clearly a number of formations (Bestunde), and to
apply definite names to them, such as ericetum, rhododen-
dretum, coryletum, pinetum, palmetum, etc. Meyen (1836)
merely adopted Schouw’s system, without adding anything
of especial importance to it. Grisebach’s recognition of
the station as a biological unit, the formation, made a per-
manent place for this concept in phytogeography, and the
study of vegetation with reference to its constituent for-
mations became more and more freauent. A. DeCandolle

14 ASSOCIATION

(1855) ignores formations and treats only incidentally of
stations: this is explained by the fact that he wrote of
botanical geography, considering the treatment of stations
to belong to botanical topography. With the work of
Kerner (1863), Grisebach (1872), Engler (1879), Hult (1881,1885),
Goeze (1882), Beck (1884), Drude (1889) and Warming (1889),
the recognition and delimitation of formations came to con-
stitute the foundation of vegetational research. a relation
which the work of the last decade has greatly emphasized.
At the present time, the formation stands in precisely the
same relation to vegetation, and hence to phytogeography,
that the species does to the flora, and to taxonomy. In con-
seauence, the primary lines of research are the same for
each, and the foundations of phytogeography must be laid
upon the development, structure and classification of for-
mations in the same thorough way that the superstructure
of taxonomy has been built upon the development, structure
and classification of species.

Since the present paper deals with vegetation as a whole,
the development of formations will be treated under succes-
sion, the structure of formations under zonation and alter-
nation, while their classification will be found under associ-
ation and succession.

In endeavoring to analyse the causes of association, it
must be kept clearly in mind that the concrete examples
from which all generalisations must be drawn are often in
very different stages of development, and are of correspond-
ingly different ages. For this reason, it has seemed best
to consider the primary relations of association in general in
this place, leaving the treatment of the effects of invasion,
succession, alternation, and zonation to be taken up under
these topics.

Various categories of association may be distinguished
according to the dominant physical factor concerned, or the
point of view taken. These will fall into two series, as we
consider the relation of plant to plant with reference to some
object or characteristic, or the grouping of plants together
in response to some dominant factor. Im the first series

KINDS OF ASSOCIATION 15

may be placed association with reference to substratum, to
the ground (occupation), and to migration: in the second be-
long light and water content association. Itshould be noted
that these are all actual associations in nature, and not con-
cepts such as the vegetation form, within which plants from
widely different associations may be classified. Naturally,
it does not follow that it is not logical or valuable to group
together those plants, such as hydrophytes, sciophytes,
hysterophytes, etc., which have a common relation to some
factor, but belong to different formations.

Stratum association (associatio stratalis). Plants mani-
fest independent or dependent association with reference to
the stratum to which they are attached and from which they
derive food or support. Independent association
(associatio contigua) is exhibited by those holophytic species
of a formation which are entirely independent of each other
with respect to mechanical support or nutrition. It is
characteristic of the greater number of the constituent
species of formations. Dependent association
(associatio mutua) is manifested in the relation between host
and parasite, stratum and epiphyte, support andliane. The
idea here involved has long been recognized. Humboldt
(1806) included lianes as one of his eighteen vegetation
forms. DeCandolle (1820:32) distinguished parasites and
false parasites, the latter growing on dead plants, or
attached to living plants, Schouw (1823 : 159) made a much
more miunte division, in which plantae parasiticae radicantes
correspond to parasites, plantae parasiticae superficiales to
epiphytes, and plantae epyphytae spuriae, plantae epizoae, etc.,
to saprophytes. Meyen (1836:70) followed Schouw in the
main, but established the group epiphytes to include lichens,
and epiphytes in the present acceptation ofthe term. Drude
(1890 : 64, 68), recognized the four groups, arranging them
among vegetation forms. Warming (895) distinguished six
kinds of association, parasitism, helotism, mutualism,

1 Clements, F. E. A System of Nomenclature for Phytogeography
Engler 31:b1 1902.

16 ASSOCIATION

epiphytes, lianes and commensalism. Commensalism cor-
responds to the primary principle of association which has
given rise to vegetation. Homogeneous commensalism is the
term applied to social exclusive plants, in which the patch
is composed of a single species, Such association is
extremely rare in nature, and, if the most minute forms be
considered, probably never occurs. On the other hand,
heterogeneous commensalism, in which individuals of more
than one species are present, is everywhere typical of vege-
tation. Warming regards saprophytism merely as a special-
ised kind of parasitism, an opinion that may well be
defended. Helotism, however, is alsoa mere modification of
parasitism, if it is not indeed parasitism pure and simple.
Mutualism is an altogether vague concept, including para-
sites, epiphytes, and endophytes of doubtful physiological
relation. Pound and Clements (18°8:101) treated lianes,
parasites and saprophytes as vegetation forms, relating
herbaceous creepers and twiners to the lianes, and dividing
the fungi and lichens into nine groups. Whatever the value
of these divisions may be from the standpoint of vegetation
forms, they represent the same relation between plant and
nutritive stratum, and with respect to association should
be merged in one group. To Schimper (1898:208) belongs
the credit of having been the first to perceive the essential
similarity of all such groups from the standpoint of associ-
ation. He terms these, plant societies (Genossenschaften),
retaining the four groups already established, lianae,
epiphyta, saprophyta and parasiticae. It is evident that
dependent association comprises extremely divergent forms,
from the slightly clinging herb, such as Galium, to the most
intense parasite. The distinction, however, is a clear one,
if restricted to that relation between plants, in which one
acts as a mechanical support or stratum, or as a nutritive
host for the other.

Ground association (associatio terrena). The first
division of formations into open and closed seems to have
been made by Engler and Drude(1893 : 55). Open formations
were detined as those having incomplete stability and

GROUND ASSOCIATION 17

heterogeneous composition, while closed formations have a
definite uniform stamp. Willkomm (1896:29) made use of
the same distinction in classifying the plant formations of
Spain, and Pound and Clements (1898 : 321, 405) related the
concept more closely to association. What is true of for-
mations is equally true of vegetation, so that association may
be regarded as open or closed with reference to the density
and thoroughness with which the plants occupy the ground.
In open association (associatio aperta), the ground is
slightly or partially occupied, readily permitting the entrance
of new plants without the displacement of those already
present. Such an arrangement 1s characteristic of the early
stages of a formation, or of a succession of formations. 1tpro-
duces unstable open formations (sporadophytia),' which arise,
usually after denudation, in sandhills, blowouts, gravel slides,
dunes, flood plains, burned areas, etc. Inclosed associ-
ation (associatio clausa ), occupation of the ground is com-
plete, and the invasion of new species can occur only through
displacement. Closed association results in stable, closed
formations (pycnophytia), such as forest, thicket, meadow and
prairie. As open association characterizes the early stages
of a succession of formations. so closed association is
peculiar to the later or last stages of all such successions. In
short, open formations represent certain phases of the
dynamic condition of vegetation, while closed formations
correspond to the relatively final static conditions of vege-
tation. It is a fundamental principle of association that
every succession from denudation, or from newly formed
soils begins with open formations, and ends with a closed
formation. The causes leading up to open and closed associ-
ation are intimately connected with development, and will
be considered under invasion and succession.

Species guild association (associatio peregrina). Drude
(1885) has distinguished a kind of association peculiar to in-
vasion, in which there is a successive or concomitant
movement of certain species of a formation into another

1Clements, F. E. A System of Nomenclature for Phytogeography
Engler 81:b1 1902.

18 ASSOCIATION

formation or region, resulting in species guilds' (Artengen-
ossenschafien). The association in this case is largely one of
community of origin or area, and of concomitance of
migration. It is especially characteristic of areas adjacent
to formational and regional limits. As itis a direct result
of invasion, the species guild will be more fully considered
under this principle.

Light association (association luminalis.) Schouw (1823:
$66) divided plants into three groups upon the basis of light
intensity in the habitats, using the terms plantae aphotistae,
subterranean or darkness plants, plantae umbrosae, shade
plants and plantae apricae, light or sunshine plants. Kabsch
(1865: 111) distinguished two classes, light plants and night
plants, i. e., subterranean, dividing the former into sun and
shade plants. Warming ({895: 15) designated sun plants as
heliophilous, and shade plants as heliophobous. Pound and
Clements ({900:166) applied the term photophilous to sun
plants and sciophilous to shade plants, while Clements (1902:
166) has made a threefold division which corresponds
essentially to Schouw’s, namely, heliophyta, sciophyta and
scotophyta.

The constituent species of formations show two funda-
mentally different groupings with respect to light In the
one case, the individuals are on the same level, or nearly so,
in such a way that each has direct access to sunlight. Such
an arrangement is characteristic of most grassland and her-
baceous formations. In the case of desert formations,
there is often considerable difference in the height of the
plants, but the distance between them is so great as to ad-
mit of direct illumination of all. This arrangement may be
termed coordinate association (associatio superior),?
In forests, thickets, and many herbaceous wastes, the
height and density of certain species enable them to domin-
ate the formation. In a dense forest, the trees receive

tPound and Clements. The Phytogeography of Nebraska 2 ed. 175

LIGHT ASSOCIATION 19

practically all the light incident upon the formation, and the
shrubs, herbs, fungi and algae of lower habit and inferior
position must adapt themselves to the diffuse light which
passes through or between the leaves. The same is equally
true of dense thickets and wastes, except that the vertical
distance is less, and the diffuseness of the light is corres-
pondingly modified. In these formations, the dominant
trees, shrubs or herbs, the facies, constitute a primary or
superior layer. The degree of subordinate associ-
ation (associatio inferior), as a result of which inferior layers
will arise, will be entirely determined by the density of the
facies. In open woodlands, which are really mixed for-
mations of woodland and grassland, the intervals, and
usually the spaces beneath the trees, also, are covered with
poophytes, showing an absence of subordination due to
light. This is the prevailing condition in the pine formation
(Pinus ponderosa-xerohylium) of the ridges and foothills of
western Nebraska. When, however, the trees’ stand
sufficiently close that their shadows meet or overlap through-
out the day, the increasing diffuseness begins to cause modi-
fication and rearrangement of the individuals. By photo-
metric methods, the light ina forest is found to be least
diffuse just below the facies, while the diffuseness increases
markedly in passing to the ground. The taller stronger
individuals are consequently in a position to assimilate more
vigorously, and to become still taller and stronger as a
result. Just as these have taken up a position inferior to
that of the facies, so the shorter or weaker species must come
to occupy a still more subordinate position. This results,
not only because the light is primarily weaker nearer the
ground, but also because the taller plants interpose as a
second screen. The complete working out of this arrange-
ment with reference to light produces typical subordinate
association, which finds its characteristic expression in the
layering of forests and thickets. Layers tend to appear as
soon as open woodland or thicket begins to pass into denser
conditions,and,up to a certain point,at which they disappear,
they become the more numerous and the more marked, the

20 ASSOCIATION

denser the forest. In the Otowanie Woods (Quercus-Hicoria
hylium), layering usually begins at a light value of .1 (1=
normal sunshine in the open). Thornber' has found the
same value to obtain in the thickets of the Missouri bluffs.
In these, again, layers disappear at a value of .005, the
extreme diffuseness making assimilation impossible except
for occasional mosses and algae. A number of herbaceous
plants are present in the spring, but these are all prevernal
or vernal bloomers, which are safely past flowering before
shade conditions become extreme. Inthe Fraxinus-Catalpa-
alsium, all inferior holophytic vegetation disappears between
the light value of .004 and that of .003. The spruce-pine
formation (Picea-Pinus-hylium) of the Rocky Mountains, with
a light value of .01, usually contains but a few scattered
herbs, mostly evergreen: in some cases there are no subord.
inate plants, other than mosses and hysterophytes. The
lodge-pole pine formation (Pinus murrayana-hylium) with
light values often less than .005, is nearly or quite destitute
of all but hysterophytic undergrowth. Such extremely
dense formations are examples of coordinate association
merely, since the formation is reduced to a single superior
layer, in which the individuals of the facies bear the same
spatial relation to incident light. In layered formations, in
addition to the subordinate relation of other species to the
facies, there is, of course, a kind of coordinate association
manifested in each layer.

Water content association (associatio aqualis). De
Candolfe (1820:14) summarized the characteristics of water
plants and dry land plants, without, however, recognising
them as two distinct groups. Schouw (1823:157) was the
first to give definite expression to the value of the moisture
content of the soil in the grouping of plants. He established
three groups: (1) swamp plants (plantae paludosae) including
also slime plants (plantae lmosae), which he regarded as
passing readily into aquatic plans (plantae emersae); (2)
“plants which grow in moist meadows’’ (plantae uliginosae,

1Thornber, J. J. The Prairiegrass Formation in Regi -
Bot. Surv. Neb. 5:36, 46 1901 ek: aa

WATER CONTENT ASSOCIATION 21

but also termed Bruchpflanzen!; (3) ‘‘plants that love a dry
soil (plantae soli aridi). In distinguishing plants with respect
tomedium, Schouw divided water plants into plantae vera
aquaticae s. planitae submersae, which he termed Hydrophyta,
and plantae aquaticae spuriae sive plantae emersae. The groups,
plantae marinae and plantae aquae dulcis, are based upon the
chemical properties of the water, and the second group is
further analysed into plantae lacustres, fluviales, fontanae,
stagnariae, etc. Species growing in saline situations are
represented by strand plants (plantae littoralis v. maritimae),
while, in arranging plants according to the chemical nature
of the soil, salt plants are designated as plantae salinae,
Halophyta. Meyen (1836:50), though in. the main following
Schouw very closely, includes all aquatic plants under
Hydrophya. To Thurmann (1849) belongs the great credit of
perceiving, at a time when the chemical nature of the soil
was thought to determine the character of the vegetation,
that the physical properties really control the water content,
and are hence of the first importance. He divided soils into
two classes; eugeogenous, those that disintegrate readily and
completely , and hence are water-retaining, and dysgeogenous,
those that strongly resist weathering and decomposition,
and in consequence lose water readily. Plants growing on
eugeogenous soils were termed hygrophilous, and those in
dysgeogenous soils, xerophilous, while those which seem to
grow indifferently in either were called ubiquitous. Thur-
mann understood clearly that it was the degree of decompo-
sition and aggregation, and not the chemical nature of the
rocks, which determined the last group, as so-called
silicious species were found to grow on calcareous soils when
these were loose, and calcareous species on silicious soils
that had become compact. A. De Candolle (1855:423), with-
‘ out attempting a grouping of plants with reference to water
content, which lay outside his field of botanical geography,
none the less clearly noticed this fundamental difference
in soils, as the following will show: ‘‘Ily a des minéraux
quise réduisent plus ou moins facilement en terre ou en
sable, et qui offrent des conditions de ténacité particuliéres:

22 ASSOCIATION

come current. Ascherson (1883:784), in a consideration of De
Candolle’s groups, first employed the word xerophyta, as a
substitute for xerophilae. Wiesner (1889:79) made use cf the
terms, hydrophyta, hygrophyta, and xerophyta, including
halophyta in the latter.

Warming (1895:116) gave a great impetus to the investi-
gation of the ecological aspects of phytogeography by
making the fundamental water content classes the basis of
his entire treatise. He considered salt plants to be distinct
from xerophytes, establishing in all four types of vegetation.

“I, Die Hydrophytenvegetation. Diese ist eine extreme
Vegetation, deren Pflanzen entweder ganz oder grészenteils
von Wasser umgeben sind oder in einem sehr wasserreichen
Boden wachsen (der Prozentgehalt an Wasser betragt ver-
muthlich mehr als 80.)

Il. Die Xerophytenvegetation ist das entgegengesetzte
Extrem, dessen Pflanzen auf Felsboden oder, jedenfalls
wihrend eines langeren Zeitraumes im Jahre, in wasserar-
mem Boden und in trockner Luft wachsen. Der Wasserge-
halt kann gewisz, wenn er am geringsten ist, unter 10% be-
tragen.

Ill. Die Halophytenvegetation schliesst sich morpholo-
gisch an die vorige nahe an, verdient aber, fir sich auf-
gestellt zu werden, eine Meinung, die unter anderem durch
Stahl’s Untersuchungen bekraftigt wird. Sieist eine sehr
extreme Vegetation, die an Salzboden gebunden ist und
deren morphologische Higenthiimlichkeiten ebenfalls durch

die Regulierung ‘der Transpiration verursacht zu sein
scheinen.

IV. Die Mesophytenvegetation umfasst die Vereine, die
an Boden und Luft von mittlerer Feuchtigkeit angepasst
sind, an einen Boden, der sich auch in dem Salzgehalte nicht
auszeichnet. Die Pflanzen sind in morphologischer und in
anatomischer Hinsicht nicht besonders extrem ausgeprigt.”’

Pound and Clements (1898:94), rejecting the term meso-
phytes, established six groups, the first three, hydrophytes,
xerophytes and halophytes, corresponding to Warming’s,
while the last three, hylophytes, poophytes and ruderal plants

WATER CONTENT ASSOCIATION 23

(aletophytes), were formed by dividing the mesophytes,
largely upon the basis of light association. Schimper (1898:
3) merged halophytes in xerophytes as only one of several
subdivisions of the latter, and termed mesophytes tropophytes,
on account of the alternation of wet and dry conditions dur-
ing their period of growth. In postulating the dictum, ‘Eis
muss zwischen physikalischer und phvsiolog-
ischer Trockenheit, bezw. Feuchtigkeit unter-
scheiden werden; letztere allein kommt fiir das Pflanzen-
leben, also auch fiir die Pflanzengeographie, in Betracht,”’
Schimper placed the study of vegetation upon a new basis.
Pound and Clements (1900:169) followed the division into the
three fundamental groups, hydrophytes, mesophytes and
xerophytes, retaining hylophytes, poophytes and aleto-
phytes as subdivisions of mesophytes.

Warming’s great contribution to ecology liesin his full
recognition of the inherent value of water content associ-
ation as its basis, and in making a logical and systematic
treatise out of the scattered results of many workers. The
exceeding timeliness of his work made it practically certain
that his views would influence the general character of
ecological research for a long time to come. The weak
points in his system were the treatment of humic acid (bog)
plants under hydrophytes, and the separation of halophytes
from xerophytes as a coordinate group. This by no means
indicates that Warming failed to see the contradiction in-
volved in the occurrence of xerophytes in apparently hydro-
phytic situations, or to appreciate the many points of simil-
arity between xerophytes and halophytes. On the contrary,
he has summed up (176) in what was for that time a very
lucid manner, the status of the relation of swamp xerophytes
to their habitat. It remained, however, for Schimper to
perceive the essential similarity of this relation, as deter-
mined by Johansen for bog plants, with that found in crymo-
phytes by Kihlmann (1890) and Goebel (1894), and in halo-
phytes by himself (1890,1891), and to give expression to the
fundamental law of habitats, namely, that it is the physio-

24 ASSOCIATION

logical water content, and not the physical, which deter-
mines the impress of the plant and of the formation.
Accepting the easily demonstrable fact that an excess of
salts or acid in the soil water, as wellas cold, tends greatly
to diminish the available water of the soil, i. e., the physio-
logical water content, it is at once seen why saline, bog and
arctic plants are as truly xerophytic as those that grow on
rocks or in desert sands. An anomalous case, which, how-
ever, physical factor records have explained fully, is pre-
sented by many plants growing in alpine gravel slides,
strands, blowouts, sandbars, etc., in which the water con-
tent is considerable, but the water loss excessive, on account
of extreme heat or reduced air pressure. The effect of these
conditions is to produce a plant xerophytic as to its aerial
parts, and mesophytic or even hydrophytic as to subter-
ranean parts. Such plants may from their twofold nature
be termed dissophytes (dissophyta, Svccds, double, durov,
7é, plant): they are especially characteristic of dysgeogenous
soils in alpine regions where transpiration reaches a
maximum, but are doubtless to be found in all gravel and
sand habitats with high water content. With these correc-
tions, the concept of water content association, which owes
much to both Warming and Schimper, but is largely to be
credited to Thurmann, becomes completely and fundamentally
applicable to all vegetation.

The discrepancies in Warming’s arrangement which have
just been mentioned have led to several attempts to rest a
fundamental distinction of groups upon some other factor
than that of water content. The most satisfactory of these
are the developmental classifications, such as those of Hult,
Graebner, Meigen and Cowles (termed physiographic by the
latter), and the nutrition content classification of Graebner.
Both classifications are valuable, especially the develop-
mental, because they furnish other view points of the many
relations of formations, but they have in no wise the funda-
mental value of the classification based upon water content.
The naturalisation and stabilisation of invading species by

WATER CONTENT ASSOCIATION 25

which the developmental series is established are determined
in the first degree by the physiological water content of the
habitat, while a careful study of the nutrient content groups
of Graebner will suffice to show that these depend in the
first place upon water, and only in a secondary degree upon
nutrition values,

Up to the present time, the general character of the
habitat, together with the gross appearance of the plant
itself, has been thought sufficient to determine the proper
position of a plant or a formation in the water content
classification. Such a method is adequate, however, only
for plants and formations which bear a distinct impress.
For an accurate classification into the three categories,
hydrophytes, mesophytes and xerophytes, it is mneces-
sary to make exact determinations of the normal
physical and physiological water of the habitat, and to sup-
plement this, in some degree at least, by histological studies.
Except in the case of saline, acid and frozen soils, the
physical water content alone will be a fairly accurate index,
especially in habitats of similar soil composition. For an
exact and comprehensive classification, however, and par-
ticularly in comparative work, the physiological water con-
tent must constitute the sole criterion. The physical water
content is readily obtained by taking soil samples from day
to day, or from time to time throughout the growing season. *
These samples are taken from the desired depth, usually
from the layers in which the root activities are greatest, in
so far as this may be determined, placed in air tight cans
and weighed as soon as possible. The cans are then opened
and oven-dried at a temperature of 40°C for three days,
though the time is much !ess for porous gravels and sands,
and is sometimes greater for the most compact clays. When
thoroughly dried, the samples are again weighed, the diff-
erence between the two weights giving the total amount of
water in the soil, i. e., the physical water. Having deter-
mined the latter, a second soil sample is taken at a time

a

1Pound and Clements l.c. 2 ed. 167 1900

26 ASSOCIATION

when the species to be investigated is completely wilted,
and the amount of water present is determined as before.
This is the non-available water. The physiological water
content is then obtained by subtracting the amount of
non-available water from the physical water content. The
one drawback to this method is the difficulty of causing the
plant to wilt in nature. This can be done only by cutting
the soil in such a way as to destroy the capillarity, and by
covering it in such a way during times of precipitation that
there is no access of moisture. A more feasible method is
to transfer the plant in its own soil to the planthouse, where
the physical factors may be accurately controlled, but this
can be used only in the case of relatively small plants. As
the absorptive power varies widely in different individuals
of the same plant, it is imperative that water content ex-
periments be conducted only with normal healthy plants at
the time of maturity. Some preliminary work in the
accurate investigation of the water content of different
habitats has been done by two of the writer’s pupils: Thorn-
ber (1901) has investigated the comparative water content
values of woodland and prairies, while Hedgcock ({902) has
made a special study of the physiological water of various
soils. The present characterisation of many plants and
formations as hydrophytic, mesophytic or xerophytic must
be regarded as largely tentative, and the final classification
will be possible only after the thorough quantitative investi-
gation of their habitats.*

The relation to water content association of the concept
underlying the groups, hylophytes, poophytes and aleto-
phytes, established by Pound and Clements in 1898, is a com-
plex one. This idea, which Schimper ({898:173) recognized
later in the same year in the corresponding divisions,
Geholz, Grasflur and Wiiste, is a valid one; though involving
~~ 1'The methods and instruments employed in the exact quantitative
determination of water content, as well as humidity, temperature,
light, wind, etc., in the various formations of Nebraska and Colorado
are treated in detail in a paper entitled, ‘‘The Physical Factors in

Ecology.’’ This paper was presented before the Botanical Society of
America at its Denver meeting in 1901, and will soon be published.

WATER CONTENT ASSOCIATION 27

light association in a certain degree in hylophytes and
poophytes, it really represents the fundamental zonation of
vegetation with reference to water, in which the first zone,
the ocean (hydrophytes), has been ignored. The proper
series, then, is ocean, forest, grassland and desert, corres-
ponding exactly to hydrophytes, mesophytes and xerophytes,
in which mesophytes, largely because of differences of
water content and humidity, but also on account of light,
break up into hylophytes (forest) and poophytes (grassland).
The same concept is thus seen to underly both series, the
apparent difference in the two arising simply from the fact
that the one, ocean, forest, grassland and desert represents
the fundamental structure of vegetation, while the other,
hydrophytes, hylophytes, poophytes and xerophytes,
emphasizes the causative factors.

From the above, it follows that Schimper’s so-called cli-
matic formations, forest, grassland and desert, are merely a
somewhat incomplete expression of water content associ-
ation. As to the validity of his division of all formations
into climatic and edaphic, there is alsoroom for grave
doubt. While there can be no question of the existence of
great formations, or series of formations, which bear a dis-
tinctive impress, yet one may well hesitate to apply the
term climatic to them. The conditions which have to do
with the water supply ofa plant are of so much more import-
ance in determining its character than those which regulate
the water loss, that all plants, and consequently the form-
ations which they constitute, are primarily influenced by
soil, i. e., they are edaphic. In the ultimate analysis, how-
ever, species and formations owe their peculiar impress to
a certain constant relation between the mean of climatic
conditions and the mean of edaphic ones. This relation be-
tween the soil and the atmosphere must be as constant in
the case of an extensive formation as in that of a restricted
one; otherwise, the formation will change character. The
difference between the two formations, other than a different

ig F. E. Schimper’s Pflanzengeographie Science 9:747

28 ASSOCIATION

relation between soil and climate, is merely one of extent,
arising out of the fact that a certain correspondence of soil
and climate prevails over a larger or smaller area, as the
case may be. Truly edaphic formations are possible only
where the soil moisture is so great as to make water loss
entirely negligible as a factor capable of producing xero-
phytic modification or a tendency toward it. This is the
case only in hydrophytic situations, Hydrophytic species
are cosmopolitan; they are much the same the world over, in
a very moist orin a very dry climate, in heat or in cold.
Water loss is normally never great enough to seriously
threaten the water supply. With mesophytes and xero-
phytes, it is very different. Here there is constantly a limit
to the water supply, and the production of mesophytic or
xerophytic vegetation depends upon the nearness with which
the water loss approaches the water supply. Hydrophytic
formations might, then, be regarded as truly edaphic, ina
sense, though mesophytic and xerophytic formations cannot
properly be called climatic. Any distinction at all on such
grounds is at present gratuitous. As is true of all funda-
mental problems in phytogeography, it must await the
general employment of quantitative methods. While our
knowledge of soil factors is in an extremely elementary con-
dition, we have no exact understanding whatsoever of the
sum of physical factors, which we term climate. According
to Schimper’s idea, as well as in the general opinion,
edaphic or soil factors are thought to vary greatly, while
climatic ones are thought to be constant over vast areas.
The investigations of the author during the last five years
indicate conclusively that this is erroneous, and that soil
factors are relatively less variable and climatic ones more
variable, as would be expected. The whole question awaits
the labors of many investigators through terms of years.

1751
1754

1805
1806
1815
1820
1823
1836
1843

1849

1855
1863
1865

1872
1873

1874

29

» BIBLIOGRAPHY

Linné, C. von
Hedenberg, A.

Humboldt, A. von

Brisseau-Mirbel, C. F.
De Candolle, A. P.
Schouw, J. F.

Meyen, F. J. F.
Grisebach, A.

Thurmann, J.

De Candolle, A.
Kerner, A.
Kabsch, W.

Grisebach, A.
Le Grand, A.

Contejean, C.

De Candolle, A.

Philosophia Botanica.

Stationes Plantarum Amoen.
Acad. 4:64.

Essai sur la Géographie des
Plantes.

Ideen zu einer Physiognomik
der Gewachse.

Elémens de Physiologie Végé-
tale, et de Botanique.

Essai Elémentaire de Géog-
raphie Botanique.

Grundziige einer allegemeinen
Pflanzengeographie.

Grundriss der Pflanzengeog-
raphie

Bericht tiber die Leistungen
in der Pflanzengeographie

Essai de phytostatique appli-
quée a la chaine duJura et
aux contrées voisines

Géographie Botanique Rais-
onée

Pflanzenleben der Donau-
lander

Das Pflanzenleben der Erde

Die Vegetation der Erde

Statistique Botanique de
Ferez Ann. Soc. Agr. Loire
17 :290

De influence du terrain sur
la végétation Ann. Nat. Sci.
5 :20 :266

Constitution dans le regne
végétal de groupes physio-
logiques applicables & la
géographie ancienne et
moderne Arch. Sci. Phys.
Nat. 1874:5

30

1879
1882
1883

1885

1886

1888
1889

1889

1890

1891

1892

1893

1895

ASSOCIATION

Engler, A.
Goeze, E.

Ascherson, P.

Drude, O.

Kerner, A.
Drude, O.

Wiesner, J.
Drude, O.

Schimper, A.F. W.

Kihlmann, A. O.
Schimper, A. F. W
Goebel, K.
MacMillan, C.

Warming, E.
Engler & Drude

Warming, E.

Versuch einer Entwicklungs-
geschichte der Pflanzenwelt

Pflanzengeographie

Von der Verbreitung der
Pflanzen Leunis Synopsis
1:724.

Die Vertheilung und Zusam-
mensetzung dstlicher Pflan-
zengenossenchaften in der
Umgebung von Dresden
Isis

Die systematische und geog-
raphische Anordnung der
Phanerogamen Schenck
Handbuch 8 :487

Pflanzenleben

Uber die Principien in der
Unterscheidung von Vege-
tationsformationen Engler
11:21

Biologie der Pflanzen

Handbuch der Pflanzengeog-
raphie

Uber Schutzmittel des Laubes
gegen Transpiration Mon-
atsb. Akad. Berl. 7

Pflanzenbiologische Studien
aus Russisch-Lappland

Die indo-malayische Strand-
flora

Pflanzenbiologische Schilder-
ungen IT

The Metaspermae of the
Minnesota Valley

Lagoa Santa

Die Vegetation der Erde
Engler 17 :b55

Plantesamfund

1896

1898

1900

1901

1902

BIBLIOGRAPHY 31

Drude, O.

Willkomm, M.

Pound & Clements

Schimper, A. F. W.

Graebner, P.

Nilsson, N. H.

Delpino, F.

Pound & Clements

Cowles, H. C

Clements, F’. E.

Deutschlands Pflanzengeog-
raphie

Grundziige der Pflanzenver-
breitung auf der Iberischen
Halbinsel

The Phytogeography of Neb-
raska

Pflanzengeographie auf physi-
ologischer Grundlage

Gliederung der Westpreussis-
chen Vegetationsformation-
en Schrift. Nat. Ges. Dan-
zig 9:48

Hiniges tiber die Biologie der
schwedischen Sumpfpfian-
zen Bot. Cent. 76:9

Studi di geografia bvutanica
secondo un nuovo indirizzo
Mem. R. Acc. Sci. 5:7 :329

The Phytogeography of Neb-
raska 2 ed.

The Physiographic Ecology
of Chicago and Vicinity
Bot. Gaz. 31:78

A System of Nomenclature
for Phytogeography Engler
31 :b1

32

INVASION

By invasion (Goeze 1882:109) is understood the movement
of plants from an area of a certain character into one of a
different character, and their colonization in the latter.
This movement may concern an individual, a species or a
group of species. From the nature of invasion, which con-
tains the double idea of going into and taking possession of,
it usually operates between contiguous formations, but it
also takes place between formational zones and patches.
More rarely and less noticeably, there may be invasion into
aremote vegetation, as a result of long carriage by wind,
water, birds, railroads or vessels. Movement or migration,
however, represents but one of the two ideas involved in in-
vasion. Migration merely carries the spore, seed or pro-
pagule into the area to be invaded. In ecesis,* the spores
or seeds germinate and grow, after more or less adjustment
and, in case the latter becomes sufficiently complete, the new
plants reproduce and finally become established. With all
terrestrial plants, invasion is possible only when migration
is followed by ecesis, because of the inherent differences of
formations or of areas of the same formation. In the case
of surface floating forms, such as Lemnaceae, and of the
plancton, ecesis is of much less importance, on account of
the uniformity of the medium and the lack of attachment,
and migration is often practically synonymous with invasion.

MIGRATION

Migration has been sometimes used loosely as a synonym
for invasion, but it is here employed in its proper sense of
removal or departure, i. e. movement, and is contrasted with
ecesis, the making of a home, the two ideas being combined
in invasion, which is a moving into and a taking possession
of. An analysis of migration reveals the presence of four
factors, mobility, agency, proximity and topography. Not
all of these are present in every instance of migration, as
for example in the simple elongation of a rootstalk, but in
the great majority of cases each plays its proper part.

1From the Greek, oixjovs, the act of coming to be at home, henc
adjustment to the habitat, olkos.

MIGRATION 33

Mobility represents the inherent capacity of a plant for mi-
gration, and in its highest expression, motility, is in itself
productive of movement. As a general rule, however,
modifications for securing mobility are ineffective in the
absence of proper agents, and the effective operation of the
two will be profoundly influenced by distance and topo-
graphy.

The historical development of the concept of migration
has been extremely fragmentary, although its recognition
dates back to the beginning of phytogeography. The need
for a systematic consideration of the subject has been
obscured by the greater interest taken in the origin and
naturalization of cultivated plants. Linné (1745:2) first
mentioned migration briefly as follows: ‘‘Migrarunt ad
floram nostram ab Exteris regionibus multae plantae, quae
suas in Suecia fixere sedes ad littora praesertim & oras
maritimas’’. Inthe Philosophia Botanica (1752:86), he has
made an excellent analysis of dissemination, distinguishing
wind-distributed parts (Volitantia) as pappose, comate,
winged and inflated, mechanically propelled seeds (Eilasticae)
as contractile, mucronate, fibrillar and creeping, and finally,
parts with devices to secure attachment as those having
hamate calyx, pericarp or seeds. He indicated, moreover,
that animals distribute seeds by deglutition and mastication,
while streams, seas, tides, lakes and rains all aid in dissem-
ination. Humboldt (1805:22) was apparently the first to em-
ploy the terms migration and mobility, but he did this only
incidentally in connection with the enforced migration of
cultivated plants. Mirbel (1815:348) treated briefly of dis-
Semination by elasticity of the pericarp and by winds,
water, birds, mammals and man, drawing the larger
number of his illustrations from Linné. He also
made a detailed classification of seeds and fruits
(593,796) according to their form and surface. DeCandolle
(1820:45) recognized the primary importance of natural
barriers (barriéres) in gradual migration, considering at some
length the obstructive effect of large bodies of water,
deserts, mountain ranges and radically different vegetation,

34 INVASION

and he pointed out that plants are able to pass barriers to a
greater or less degree by reason of natural or artificial
means of transport, such as water, winds, animals and man.
Link (1820:263) observed the descent of alpine plants into
river valleys, pointing out the agency of mountain streams,
and indicating also the activity of ocean currents in bring-
ing about transportation, Schouw’s silence in regard to mi-
gration would be inexplicable in view of the fact that his
book is largely a treatise on distribution, were it not for a
chance statement (1823:182) in which he speaks of “Die An-
hanger der Migrationstheorie’’, and a note (184) in which he
says: ‘‘Diese Theorie ist in der nevesten Zeit von Mannern
als DeCandolle, Link, und von Buch vertheidigt worden’’.
Meyen ({836:39) considered briefly the currents of the air and
ocean as transportive agents, but added little of importance
to Link’s account. DeCandolle (1832:595) considered the
natural dissemination of seeds under the following heads:
fruits pseudospermes (achenes, etc.) in which the fructification
plays a special part by the elongation of the peduncle,
the opening of the involucre or the swelling of the re-
ceptacle, or the fruit is itself pappose, barbed, etc.;
fruits charnus (fleshy fruits); fruits capsulaires, and des plantes
hypocarpogées. Henfrey (1852:50) has discussed the agents
of dissemination in an interesting manner, though he did
not contribute any new matter, with the exception ofa short
treatment of barriers. A. DeCandolle ({855:613) considered
the causes of transport ina most minute though somewhat
unsystematic fashion. His book is a mine of details,
especially in regard to cultivated species. He was the first
to point out that, as a rule, barriers are obstacles to natura-
lization rather than to migration. Darwin (1859:624) brought
forward in a chapter on the means of dispersal a large
number of experiments and observations relating to the
transport of seeds by ocean currents, birds and other
animals. Kabsch (865:543) did not attempt a consideration
of all transportive agents, but he gave particular attention
to the action of water currents and of glaciers.

MIGRATION 35

Hildebrand (1873) brought together the results of various
observers in a treatise on dissemination, which is still the
most extensive and the most important in this field. He
divided distributive agents into winds, water, animals,
dessication, and developmental features which effect distri-
bution, such as turgescence, growth and motility, making
a minute analysis of the contrivances under each. He
classified contrivances for wind distribution as: (a) small-
ness and lightness, (b) winged structures, (c) hairy and
feathery modifications of the seed, fruit, style, peduncle,
rhachis or glumes. Adaptations for water distribution are
relatively few, consisting mostly of air-containing tissues or
organs. Animal-distributed parts are divided into: (a)
fleshy fruits, (b) hooked fruits and (c) glandular fruits. The
author furthermore discussed the significance of the lack of
useless modifications, the distribution of dissemination con-
trivances in the various groups and their influence upon mi-
gration. Grisebach (1877:4) established a fundamental law
of barriers as follows: ‘‘La loi supréme servant de base a
l’établissement persistant de flores naturelles, doit done étre
reconnue dans les barriéres qui enont entravé ‘ou complete-
ment empéché le mélange,’ and he illustrated its application
briefly ina few general cases. He considered the general
facts of migration of arctic-alpine plants and of forest and
steppe plants, but more with reference to the interchange of
species between regions than with respect to the methods
and agents‘in dispersion. Comber (874:248) endeavored to
relate modifications for dissemination, such as coma, pappus,
spines, etc. to the geographical area of the species of the
British fiora, but, while this method deserves a more
thorough trial, his results are too conflicting to be of much
value.

An extremely important contribution to the subject is that
of Engler (1879), but as this work deals with invasion as a
whole rather than with either of its parts, migration or
ecesis, consideration of it will be reserved for another place.
Goeze (1882:96) grouped migration agents in two classes, the
one including the various aqueous agents, currents, streams,

36 INVASION

rains, etc., and the other comprising winds, animals and
man. Hult ({886:b/) andeavored to show that moss spores
and, in consequence, the spores of all cryptogams are not
disseminated by the wind over great stretches. His evi-
dence, however, is drawn entirely from distribution, with
little regard to the unique importance of ecesis, and hence
it affords no real support to his contention. He has made
much of the fact that the mosses which invade a denuded
area are mostly drawn from neighboring formations, but
this signifies merely that the wind carries the greater
number of spores a short distance rather than a long one.
Huth (1887) wrote a comprehensive treatise upon houked
and retrorsely barbed fruits, enumerating the examples in a
long list of families and indicating their relation to distribu-
tive agents. Dingler (1889 :331) investigated the comparative
transportability of wind-distributed seeds'and fruits, as de-
termined by their velocity in falling. Asa result of his ex-
periments, he made the following division of disseminules:
(1) dustlike, Micrococcus, spores, Lycoperdon; (2) grainlike,
Papaver, Sibbaldia; (8) bladder-inflated, Astragalus, Ostrya.
(4) filifurm, Bromeliaceae; (5) disciform, Iris, Ulmus; (6) con-
vex-disciform, Ptelea; (7) parachute-like, Taraxacum, Vale-
riana, Asclepias, Salix, Dryas, Puisatilla; (8) winged-turbin-
iform, Rumex; (9) elongate-lamelliform, Ailanthus, Tecoma;
(10) elongate-lamelliform, seed at the side, Bignonia; (11)
elongate-lamelliform, seed at the end, Frawxinus; (12) elon-
gate-lamelliform, seed at end but one side also weighted,
Acer, Pinus. Wiesner (1889:105) summarized briefly but
somewhat comprehensively the subject of migration, while
Drude ($890:100) touched it in a more general way.

Kerner (1892:791) has furnished an account of dissemin-
ination which rivals that of Hildebrand. The wealth of de-
tail especially is something extraordinary. Disseminules
are grouped under two main heads: offshoots, and fruits
and seeds, though the author recognizes that whole plants
are sometimes distributed. Under offshoots are considered
mycelia, protonemata, roots, root-stalks, runners, hormo-
gones, zoogonidia, soredia, gemmae, buds, etc., while their

MIGRATION 37

dispersal is treated with respect to motility, growth, water,
wind, expulsive mechanisms, animals and man. Under
fruits and seeds, there is recognized a large class of sling-
fruits in which propulsion is effected by turgidity, dessi-
cation, torsion or elasticity, and a small group of creeping
and hopping fruits. With respect to agents, Kerner treats
of dissemination by water, including drainage, by water and
wind, and by wind alone, distinguishing under the latter,
rolling and flying fruits, which are flattened, winged, comate
or parachute-like. Migration by the agency of animals is
by means of deglutition, concealment, or attachment, the
latter occurring by means of mud, water, mucilage, gland-
ular hairs or barbed processes. Attention is also given to
the elongation of peduncles and to other contrivances by
which seeds are placed in a position to be more effectively
influenced by distributive agents. Excellent monographs
of the dissemination contrivances in particular families have
been made by Dammer (1893:260) for Polygonaceae and by
Buchwald (1895 :494) for Leguminosae. Pound & Clements (1898:
153) grouped contrivances for wind distribution in four
classes; (1) comate and pappose seeds; (2) winged seeds;
(8) winged fruits; (4) tumbleweeds. Water distribution is
by streams or by surface drainage, while dissemination by
means of animals occurs by deglutition, carriage or attach-
ment. Schimper (1898:32) has simply considered the general
relation of wind and water to dissemination.

Mobility (mobilitas) denotes potentiality of migration as
represented by modifications for this purpose. It corres-
ponds, in a sense, to dissemination, though seed production
also enters into it. Its most perfect expression is found in
those plants which are themselves motile, Bacteriaceae,
Oscillatoria, Volvocaceae, and Bacillariaceae, or possess motile
propagules, such as most Phycophyta. On the other hand it
is entirely undeveloped in many plants with heavy un-
Specialized seeds and fruits. Between these two extremes
lie by far the greater number of plants, exhibiting the most
various degrees of mobility, from the motile though almost
immobile offshoots of many Liliaceae to the immotile but very

38 INVASION

mobile spores of fungi. It is thus seen that motility plays
a relatively small part in migration, being practically absent
in terrestrial forms, and that it bears a very uncertain re-
lation to mobility. In analysing the latter, contrivances for
dissemination are seen to determine primarily the degree of
mobility, while the number of seeds produced will have an
important effect in increasing or decreasing it. A third
factor of considerable importance is also involved, namely,
position with reference to the distributive agent, but any
exact knowledge of its importance must await systematic
experiment somewhat after the methods of Dingler, but
with air-currents, etc., of known velocity and direction.
The time is not distant when by such methods it will be
possible to establish a coefficient of mobility, derived from
terms of position, weight, resistant surface, and trajectory
for definite wind velocities or for particular propulsive
mechanisms.

Plants exhibit considerable diversity with reference to the
part or organ modified, or at least utilized, for dissemination.
This modification, though usually affecting the particular
product of reproduction, may, in fact, operate on any part
of the plant and in certain cases, upon the entire plant itself.
In the majority of plants characterized by alternation of
generations, the same individual may be disseminated in one
generation by a reproductive body, and in the other by a
propagative one, as is the case in the oogones and conidia of
Peronospora, the spores and gemmae of Marchantia, the fruits
and runners of Fragaria, etc. Special modifications have,
as a rule, been developed in direct connection with spores
and seeds, and mobility reaches its highest expression in
these. It is, on the other hand, greatly restricted in off-
shoots and plant bodies, at least in terrestrial forms, though
it will now and then attain a marked development in these,
as shown by the rosettes of Sempervivum and the tumbling
plants of Cycloloma. For the sake of convenience, in analys-
ing migration, all plants may be arranged in the following
groups with reference to the organ or part distributed,

MIGRATION 39

1, Spore-distributed, sporostrotes' (Sporostrotae, o7opd,
7 Spore, otpwrds, 7, dv, strewn.) This includes all plants
possessing structures which go by the name of spore, such
as the acinetes of Nostoc and Protococcus, the zoogonidia of
Ulothrix, Ectocarpus, etc., the conidia, ascospores and basid-
iospores of fungi, the tetraspores of red seaweeds, and the
gemmae and spores proper of liverworts, mosses and ferns.
These are almost always without especial contrivances for
dissemination, but their extreme minuteness results in great
mobility.

2. Seed-distributed, spermatostrotes (Spermatostrotae,
onépya, 76, seed). This group comprises all flowering plants
in which the seed is the part modified or at least dissemin-
ated. The mobility of seeds is relatively small, except in
the case of minute, winged or comate seeds.

3. Fruit-distributed, carpostrotes (Carpostrotae, xapwés, 6,
fruit). The modifications of the fruit for distribution exceed
in number and variety all other modifications of this sort.
All achenes, perigynia, utricles, etc., properly belong here.

4, Offshoot-distributed, thallostrotes (Thallostrotae, Oaddds,
6, shoot). To this class are referred those plants, almost ex-
clusively cormophytes. which produce lateral, branch-like
propagules, such as root-sprouts, rhizomes, runners, stolons,
rosettes, etc. Migration with such plants is extremely slow,
but correspondingly effective, since it is almost invariably
followed by ecesis.

5. Plant-distributed, phytostrotes (Phytostrotae, putov, rd,
plant). This group includes all plancton and surface forms,
whether motile or non-motile, and those terrestrial plants in
which the whole plant, or at least the aerial part, is dis-
tributed, as in tumbleweeds and in many grasses.

Any investigation of migration to be exact must confine
itself to fixed forms, and for these the degree of perfection

‘Throughout the present paper, Greek or Latin equivalents have
been proposed for practically all terms, because of the conviction that
a uniform international nomenciature is as imperative and as certain
for phytogeography, as it has beenfor taxonomy. The English form,
however, is given precedence, since it alone will suffice for the majority
of English-speaking botanists.

40 INVASION

shown by dissemination contrivances corresponds almost
exactly to the degree of mobility, Because of the difficulty
of ascertaining the effect of ecesis, it is impossible to deter-
mine the actual effectiveness in nature of different modifi-
cations, and the best that can be done at present is to regard
mobility, together with the occurrence and forcefulness of
distributive agents, as an approximate measure of migration.
The general accuracy of such a measure will be more or less
evident from the following. Of 118 species common to the
foothill and sandhill regions of Nebraska, regions. which are
sufficiently diverse to indicate that these common species
must have entered either one by migration from the other,
83 exhibit modifications for dissemination. while 8 others,
though without special contrivances, are readily distributed
by water, and 4 more are mobile because of minuteness of
spore or seed. Some degree of mobility is present in 73 per
cent of the species common to these regions, while of the
total number of species in which the mode of migration is
evident, viz. 95, 66 per cent are wind-distributed, 20 per
cent animal-distributed, and 14 per cent are water-distributed.
It need hardly be noted that this accords fully with the
prevalence and forcefulness of winds in these regions. Of
the species peculiar to the foothill region, many are doubt-
less indigenous, though a majority have come from the
montane regions to the westward. The number of mobile
species is 121, or 60 per cent of the entire number, while the
number of wind-distributed onesis 85, or 70 per cent of
those that are mobile. Among the 25 species found in the
widely separated wooded bluff and foothill regions, 2 only,
Amorpha nanaand Roripa nasturtium, are relatively immobile,
but the minute seeds of the latter, however, are readily dis-
tributed, and the former is altogether infrequent.

The following groups of plants may be distinguished ac-
cording to the character of the contrivance by which dis-
semination is secured.

1. Saccate, saccospores (Saccosporae, cdxxos,6,8ack, oropd, 4,
seed, fruit). Here are to be placed a variety of fruits, all
of which agree, however, in having a membranous envelope,

MIGRATION 41

or an impervious, air-containing pericarp. In Ostrya, Phy-
salis, Staphylea, the modification is for wind-distribution,
while in Carex, Nymphaea, etc., it is for water-transport.

2. Winged, pterospores (Pterosporae, arepov, 76, wing).
This group includes all winged, margined, and flattened
fruits and seeds, such as are foundin Acer, Betula, Rumex,
many Umbelliferae, Graminaceae, ete.

3. Comate, comospores (Comosporae, xéuy, 4, the hair of
the head). To this group belong those fruits and seeds with
long silky hairs, Gossypiwm, Anemone, Asclepias, etc., and
those with straight capillary hairs or bristles not confined
to one end, Typha, Salix, etc.

4. Parachute, petasospores (Petasosporae, réracos, 7, Sun-
shade, umbel). The highly developed members of this
group, Taraxacum, Lactuca, and other Liguliforae are con-
nected through Senecio and Eriophorum with the preceding.
These represent the highest development of mobility at-
tained by special modification.

5. Chaffy-pappose, carphospores (Carphosporae, xdpdos, 76,
scale, husk of fruit). In this group are placed those achenes
with a more or less scaly or chaffy pappus with slight
mobility, as in Rudbeckia, Brauneria, Helianthus, etc.

6. Plumed, lophospores (Lophosporae, Addos, 6, crest,
plume). In the fruits of this class, the style is the part
usually modified into a long plumose organ, possessing a

high degree of mobility as in Pulsatilla, Sieversia and
Clematis.

7. Awned, acospores (Acosporae, éxy, #, point). These
are almost exclusively grasses, in which the awns serve for
distribution by wind, water or animals, and even, according
to Kerner, by hygroscopic creeping movements. The
mobility in many cases is great.

8. Spiny, centrospores (Centrosporae, xévrpov, 70, spur,
spine). This group contains a few representatives which
possess a moderate degree of mobility by attachment, as in
Tribulus and Cenchrus.

9. Hooked, oncospores (Oncosporae, 6’yxos, 6, hook, barb).
The members of this group are extremely numerous, and

42 INVASION

the degree of mobility as a rule is very high. All exhibit in
common the development of hooks or barbs, by which they
are disseminated in consequence of attachment, though the
number, size and disposition of the hooks vary exceedingly.

10. Viscid, gloeospores (Gloeosporae,* yAows, 6, a sticky,
clammy stuff). In these. the inflorescence is more or less
covered with a viscid substance, as in species of Silene, or
the fruit is beset with glandular hairs, as in Cerastium,
Salvia, ete.

11. Fleshy, sarcospores (Sarcosporae, cépf, capxes, 4, flesh,
pulp of fruit). These are intended for dissemination by
deglutition, largely by birds; the effectiveness of the modifi-
cation depends in a large degree upon the resistance of the
seed envelope to digestion. The mobility varies greatly,
but the area over which migration may be effected is large.

12. Nut-fruited, creatospores (Creatosporae, xpéas, atos, Td,
meat). This group includes those plants with nut fruits,
which are carried away and secreted by animals for food.

18. Flagellate, mastigospores (Mastigosporae, pdoré, syos, 7,
lash). These are plants with ciliate or flagellate propa-
gative cells, i.e. zoogonidia, as in Protococcus, Ulothria,
Oedogoninm, Ectocarpus, etc., or with plant bodies similarly
motile, Bacteriaceae and Volvocaceae.

The position on the plant of the organ to be disseminated,
i.e., its exposure to the distributing agent, plays a consider-
able part in determining the degree of mobility. In the
majority of plants, the position of the inflorescence itself re-
sults in maximum exposure, but in a large number of forms
special modifications have been developed for placing the
spores or seeds in a more favorable position. In both cases,
there are often present also devices for bringing about the
abscission of the seed or fruit. lt is moreover self-evident
that the height of the inflorescence above ground or above
the surrounding vegetation is likewise of considerable im-
portance in increasing the trajectory. It is yet too early
to make a complete classification of contrivances for
placing disseminules in the most favorable exposure, but the
following will serve as a basis for future arrangements.

MIGRATION 43

1. In all operculate Discomycetes, and especially in the
Ascobolaceae, where the asci project above the hymenium,
the spores are raised above the surface by tensions within
the apothecium. This might be regarded as dissemination
by expulsion, if it were not for the fact that the spores fall
back into the cup. unless carried away by the wind.

2. In Gasteromycetes and in certain Hepaticae. the spores
are not only elevated slightly above the sporophore by the
expanding capillitium or by the mass of elaters, but they
are also held apart in such a way that the wind blows them
out much more readily.

3. In Bryophyta, the sporophore regularly dehisces by a
slit, or is provided with a peristome. Both structures are
for the purpose of sifting the spores out into the wind: by
reason of their hygroscopicity, they also insure that the
spores will not be shaken out in wet weather.

4. Ina few grasses, such as Stipa and Aristida, the twist-
ing and interwining of the awns lift the floret out of the
glumes, and at the same time constitute a contrivance
readily blown away by the wind or carried by attachment.

5. In certain Compositae, the involucral scales are reflexed
at maturity, and at the same time the disk becomes more or
less convex, serving to loosen the achenes. This result is
also secured in certain species by the drying and spreading
of the pappus hairs.

6. The scapose Liguliflorae, Taraxacum, Agoseris, etc., are
characterized by the elongation of the scape after anthesis,
with the result that the head is raised toa considerable
height by the time the achenes are mature.

7. Carpotropic movements, though primarily for another
purpose, often serve to bring seeds and fruits into a better
position for dissemination.

The relation of spore or seed-production to mobility is
obvious in the case of mobile species: in the case of im-
mobile ones, it is just as evident that it has no effect, though
it may still have considerable influence in increasing mi-
gration. In the case of two species with equally effective
dissemination contrivances, the cne with the largest seed-

44 INVASION

production will be the more mobile. On the basis of the re-
lation of seeds to flower, two groups of plants may be dis-
tinguished’, one, Polyanthae, in which the flowers are many
and the seeds few or single, as in Compositae, and the other,
Polyspermatae, Portulaca, Yucca, etc., in which the number
of seeds to each flower is large. So far as the actual number
of seeds produced is concerned, polyanthous plants may not
differ from polyspermatous ones, but, as a rule, they are
much more highly specialised for dissemination and are
more mobile. The number of fertile seeds is also much
greater, a fact which is of great importance in ecesis, and
which, taken in connection with mobility, partially explains
the supremacy of the composites. Among the fungi and
algae, the amount of spore-production in a large degree de-
termines the mobility, since these forms are intrinsically
permobile.

In the last analysis, however, the possibility of migration
depends upon the action of distributive agents: in the
absence of these, even the most perfect contrivance is value-
less, while their presence brings about the distribution of
the most immobile form. In short, migration depends much
more upon such agents than upon mobility, however perfect
the latter may be. It is, moreover, evident that the amount
and extent of migration will be determined primarily by vhe
permanence and forcefulness of the agent. as indicated by
its ability to bring about transportation. Finally, as will
be shown later, the direction and rapidity of migration de-
pend directly upon the direction and intensity of the agent.

Migration results when spores, seeds, fruits, offshoots, or
plants are moved out of their home by water, wind, animals,
man, gravity, glaciers, growth, or mechanical propulsion.
Corresponding to these agents, there may be recognized the
following groups.

1. Water, hydrochores (Hydrochorae, i8wp, i8aros, ro, S8po-,
water, xwpéw, spread abroad). These comprise all plants
distributed exclusively by water, whether the latter acts as
ocean currents, tides, streams, or surfacerun-off. In the

1Pound and Clements Phytogeography of Nebraska 84 1898.

MIGRATION 45

case of streams and run-off, especially, mobility plays little
part, provided the disseminules are impervious, or little
subject to injury by water. Motile plants, or those with
motile cells, which belong entirely to this group, may be
distinguished as autochores (Autochorae, airds, self), which
correspond closely to mastigospores.

2. Wind, anemochores (Anemochorae, y'veuos, wind). This
group’ includes the majority of all permobile terrestrial
plants, i.e. those in which modifications for increasing sur-
face have been carried to the extreme, or those which are
already permobile by reason of the minuteness of the spore
or seed. Saccate, winged, comate, parachute, pappose,
plumed, and, to a certain extent, awned seeds and fruits re-
present the various types o* modifications for wind-distri-
bution.

3, Animals, zoochores (Zoochorae, é6ov,70, animal). Among
terrestrial plants, dissemination by attachment represents
essentially the same degree of specialisation as is found in
wind-distributed plants. The three types of contrivances
for this purpose are found in spinose, hooked, and glandular
fruits. Dissemination by deglutition and by earriage, either
intentional or unintentional, though of less value, play a
striking part on account of the great distance to which the
seeds may be carried. Dissemination by deglutition is
characteristic of sarcospores, and distribution by carriage
of creatospores.

4. Man, brotochores (Brotochorae, Bporos, 6, a mortal man).
Dissemination by man has practically no connection with
mobility. It operates through great distances and over im-
mense areas as well as near at hand. It may be intentional,
as in the case of cultivated species, or unintentional, as in
thousands of native or exotic species. No other dissemin-
ating agent is comparable with man in respect to universal
and obvious migration.

5. Gravity, clitochores (Clitochorae, xXéros, ro, slope). The
members of this group are.exclusively colline, montane, and
alpine plants, growing on rocks, cliffs, and gravel-slides
(talus), etc., in which the seeds reach lower positions merely

46 INVASION

by falling or more frequently, by the breaking away and
rolling down of rock or soil masses and particles. Dissem-
ination by this method is relatively insignificant, though it
plays an important part in the rock fields and gravel slides
of mountain regions, particularly in the case of immobile
species.

6, Glaciers, crystallochores (Crystallochorae, xptvotaAXos, 6,
clear ice). At the present time, transport by glaciers is of
slight importance, because of the restriction of the latter to
alpine and polar regions, where the fiora is poorly developed.
In the consideration of migrations during the glacial epoch,
however, it plays an important point.

7. Growth, blastochores (Blastochorae, Bdéorn, 7, growth).
The mobility of species disseminated by offshoots is ex-
tremely slight, and the annual movement relatively insigni-
cant. The certainty of migration and of ecesis, is, however,
so great, and the presence of offshoots so generally the rule
in terrestrial plants that growth plays an important part in
migration, especially within formations.

8. Propulsion, bolochores (Solochorae, Body, 4, a throw).
Like growth, dissemination by mechanical propulsion,
though operating through insignificant distances, exerts an
important effect in consequence of its cumulative action.
The number of plants, however, with contrivances for pro-
pulsion is very much smaller than the number of blasto-
chores. All bolochorous species agree in having modifi-
cations by means of which a tension is established. At
maturity,this tension suddenly overcomes the resistance of
sporangium or fruit, and throws the enclosed spores or seeds
to some distance from the parent plant. In accordance with
the manner in which the tension is produced, sling-fruits
may be classified as follows.

(a) Hygroscopicity, pladoboles (Pladobolae, zAd8os,0, mois-
ture,-0dos, thrown). These include the ferns with annulate
sporangia, in which the expansion of the annulus by the
absorption of moisture, bursts the sporangium more or less
suddenly, though the actual propulsion of the spores seems
to come later as a result of dessication.

MIGRATION 47

(b) Turgescence, edoboles (Oedobolae, offos, ro, swelling),
Dissemination by turgescence is highly developed in
Pilobolus and in Discomycetes, though in the latter turgescence
results rather in placing the spores in a position to be
readily carried by the wind. Impatiens and Ovxalis furnish
familiar examples of fruits which dehisce in consequence of
increased turgidity.

(c) Dessication, xerioboles (Xeriobolae, énpia, 4, dryness).
The number of fruits which dehisce upon drying is very
large, but only a small portion of these expel their seeds
forcibly. Geranium, Viola, Erysimum, and Lotus illustrate
the different ways in which dessicatiou effects the sudden
splitting of fruits.

(d) Resilience, tonoboles (Tonobolae, rovos, o, a stretching
or tension). In some plants, especially composites, labiates
and borages, the achenes or nutlets are so placed in the per-
sistent calyx or involucre that the latter serves as a sort of
mortar for projection, when the stem of the plant is bent to
one side by any force, such as the wind or an animal. It
will be noticed that two separate agents are actually con-
cerned in dissemination of this sort.

Frequently, two or more agents will act upon the same
disseminule, usually in succession. The possibility of such
combinations in nature is large, but actual cases seem to be
infrequent, except where the activities of man enter into the
question. Some parts, moreover, such as awned inflor-
escences, are carried almost equally well by wind or animals,
and may often be disseminated by the cooperation of these
two agents. The wind also often bluws seeds and fruits into
streams by which they are carried away, but here again,
parts adapted to wind-dissemination are injured as a
tule by immersion in water, and the number of plants
capable of being scattered’ by the successive action of wind
and water is small.

In the present state of our knowledge of migration, it is
impossible to establish any definite correspondence between
dissemination-contrivance, agent, and habitat. As a general
rule, plants growing in or near the water, in so far as they

48 INVASION

are modified for this purpose at all, are adapted to water-
carriage. Species which grow in exposed grassy or barren
habitats are for the most part anemochores, while those that
are found in the shelter of forests and thickets are usually
zoochorous, though the taller trees and shrubs, being ex-
posed to the upper air-currents, are generally wind-distri-
buted. There is then a fair degree of correspondence, in
as much as most hydrophytes are hydrochorous, most hylo-
phytes, zoochorous, and the majority of poophytes and
xerophytes, anemochorous. Definite conclusions can be
reached, however, only by the statistical study of represent-
ative formations.

With respect to their activity, agents may be distinguished
as constant, as in the case of currents, streams, winds,
slope, growth, and propulsion, or intermittent, animals and
man. In the former, the direction is more or less determin-
ate, and migration takes place year by year, i.e., it is con-
tinuous, while in the latter dissemination is largely an
accidental affair, indeterminate in direction, and recurring
only at indefinite intervals. The effective conversion of
migration into invasion is greatest when the movement is
continuous, and least when it is discontinuous, since, in the
latter, species are usually carried not only out of their par-
ticular habitat but even far beyond their geographical area,
and the migration, instead of being an annual one with the
possibility of gradual adjustment, may not recur for several
years, or may, indeed, never take place again. The rapidity
of migration is greatest in the case of intermittent agents,
while the distance of migration is variable, being great
chiefly in the case of man, ocean-currents and wind, and
slight when the movement is due to slope, growth or pro-
pulsion. Disregarding the great distances over which arti-
ficial transport may operate, seeds may be carried half way
across the continent in a week by strong-flying birds, while
the possibilities of migration by growth or expulsion are
limited to a few inches, or, at most, toa few feet per year.
This slowness, however, is more than counterbalanced by

MIGRATION 49

the enormously greater number of disseminules, and their
much greater chance of becoming established.

The direction of migration is indeterminate, except in the
case of those distributive agents which act constantly in the
same direction. The general ‘tendency is, of course, for-
ward, the lines of movement radiating in all directions from
the parent area. This is well illustrated by the operation
of winds which blow from any auarter. In the case of the
constant winds, migration takes a more or less definite
direction, the latter being determined toa large degree by
the fruiting period of any particular species. In this con-
nection, it must be kept clearly in mind that the position of
new areas with reference to the original home of a species
does not necessarily indicate the direction of migration, as
the disseminules may have been carried to numerous other
places in which ecesis was impossible. The local distri-
bution of zoochorous species is of necessity indeterminate,
though distant migration follows the pathways of migratory
birds and animals. In so far as dissemination by man takes
place along great commercial routes, or along highways, it
is determinate. In ponds, lakes and other bodies of stand-
ing water, migration may occur in all directions, but in
ocean currents, streams, etc., the movement is determinate,
except in the case of motile species. The dissemination of
plants by slopes, glaciers, etc., is local and definite, while
propulsion is in the highest degree indeterminate. Migra-
tion by growth is equally indefinite, with the exception that
hydrotropism and chemotropism result in a radiate move-
ment away from the mass, while propulsion throws seeds in-
differently into or away from the species-mass. From the
above, it will be seen that distant migration may take place
by means of water, wind, animals or man, and, since all
these agents act in a more or less definite direction over
great distances, that it will be in some degree determinate.
On the other hand, local migration will as regularly be in-
determinate, except in the case of streams and slopes. The
direction of migration then is controlled by these distribu-
tive agents, and the limit of migration is determined by the

50 INVASION

intensity and duration of the agent, as well as by the
character of the space through which the latter operates.
ECESIS.

By the term ecesis is designated the series of phenomena
exhibited by an invading disseminule, from the time it
enters a new formation until it becomes thoroughly estab-
lished there Ina word, ecesis is the adjustment of a plant
to a new habitat. It comprises the whole process covered
more or less incompletely by acclimatisation, naturalisation,
accomodation, ete. Itis the decisive factor in invasion, in
as much as migration is entirely ineffective without it, and is
of great value in indicating the presence and direction of
migration in a great dumber of species where the dissem-
inule is too minute to be detected, or too little specialised to
be recognisable.

Humboldt (1805:21) touches the subject of ecesis only in-
cidentally in speaking of the lack of sufficient flexibility in
any known species of phanerogams to enable it to accomo-
date itself to all latitudes and altitudes. DeCandolle (1820:
54) deals with naturalisation in a very general way, and
cites several instances of its operation in adventive species.
Henfrey ({852:51) speaks of the inability of alpine plants to
accomodate themselves completely to lowland conditions, in
which, however, they often persist in consequence of con-
tinuous migration. A. DeCandolle ({855:623) considers
naturalisation at length, but almost wholly with reference
to results, so that his excellent discussion belongs almost
entirely to distribution. He gives a comprehensive though
summary account of the obstacles to naturalisation, treats of
the latter at small and great distances, and concludes with
an account of the origin of cultivated species. Darwin
(1859), in his chapter on the struggle for existence, discusses
with more or less detail the biological conditions under
which ecesis takes place in an invaded formation. He
argues for a wide range of adaptability in most organisms,
on account of their power of acclimatisation, though he does
not produce any evidence of this from the plant kingdom.
Grisebach (1872 :215, 264) pays especial attention to the inter-

ECESIS 51

change of arctic and alpine plants, and formulates the funda-
mental law of barriers, viz.,: ‘‘les plantes endemiques
augmentent en raisun des obstacles qui s’opposent & leur ex-
tension.’? Nageli ($874:109) lays down an exact procedure
for investigating the struggle for existence. His most im-
portant conclusion is that a stronger plant rarely drives the
weaker one out entirely, but that their numerical relation is
an expression of the ratio between their capabilities for
existence. Engler (1879: XI) recognizes that the viability of
seeds differs widely, and that the chances of ecesis depend
directly upon the length of time necessary for migration.
He connects ecesis directly with distribution in the principle
that ‘‘Allmélig verbreiten sich die Formen eines Formen-
kreises soweit Bodenverhialtnisse, klimatische Verhiltnisse,
und Concurrenz anderer Planzen es gestatten.’’ Warming
(1895:351), in connection with commensalism and succession,
summarizes in a comprehensive manner the effect of occupa-
tion upon ecesis. Schimper ({898:55) treats acclimatisation
briefly, taking into consideration adjustment to temperature
alone.

The relation of migration to ecesis is a most intimate
one: the latter depends in a large measure upon the time,
direction, rapidity, distance and amount of migration. In
addition, there is an essential alternation between the two,
in as much as migration is followed by ecesis, and the latter
then establishes a new centre from which further migration
is possible, and so on. The time of year in which fruits
mature and distributive agents act has a marked influence
upon the establishment of a species. Disseminules designed
to pass through a resting period are often brought into con-
ditions where they germinate at once, and in which they
perish because of unfavorable physical factors, or because
competing species are too far advanced. On the other hand,
spores and propagules designed for immediate germination
may be scattered abroad at a time when conditions make
growth impossible. The direction of movement is decisive
in that the seed or spore is carried into a habitat sufficiently
like that of the parent to secure establishment, or into one

62 INVASION

so dissimilar that germination is impossible, or at least is
not followed by growth and reproduction. The rapidity and
distance of migration have little influence, except upon the
less resistant disseminules, conidia, gemmae, etc. Finally,
the amount of migration, i. e., the number of migrants, is of
the very greatest importance, affecting directly the chances
that vigorous disseminules will be carried into places where
ecesis is possible.

Normally, ecesis consists of three essential processes,
germination, growth and reproduction. This is the rule
among terrestrial plants, in which migration regularly takes
place by means of a resting part. In free aquatic forms,
however, the growing plant or part is usually disseminated,
and ecesis consists merely in being able to continue growth
and to insure reproduction. Here establishment is practi-
cally certain, on account of the slight differences in aquatic
habitats, excepting of course the extremes, fresh water and
salt water. The ease indeed with which migration and
ecesis are effected in the water often makes it impossible to
speak properly of invasion in this connection, since aquatics
are to such a large extent cosmopolitan. In dissemination
by offshoots, the conditions are somewhat similar, Here
also, ecesis comprises the sequence of growth and repro-
duction, and invasion, in the sense of passing from one
habitat to another, is of rare occurrence, as the offshoot
grows regularly under the same conditions as the parent
plant. The adjustment of growing plants and parts is so
slight, and their establishment so certain on account of their
inability to migrate into very remote or different habitats,
that they may be ignored in the following discussion.

In accordance with the above, it would be possible to.
distinguish three groups of terrestrial plants, (1) those
migrants which germinate and disappear, (2) those which
germinate and grow but never reproduce, (3), those which
reproduce, either by propagation or generation, or both.
Such a classification has little value, however, since the
same species may behave in all three fashions, depending
upon the habitat to which it has migrated, and since

ECESIS 53

invasion does not occur unless the plant actually takes pos-
session, i.e., reproduces. From the latter statement, it
follows that invasion occurs only when a species migrates to
a new place, in which it germinates, matures and reproduces;
maintainance by annual invasion simply, in which the plants
of each year disappear completely, cannot then be regarded
as invasion proper. On the other hand, though such
instances are rare, it is not necessary that the invaders pro-
duce fruit, provided they are able to maintain themselves, or
to increase by propagation. Furthermore, if a plant germi-
nate,grow and reproduce, it is relatively immaterial whether it
persist for a few years or for many, since, as we shall see
under Succession, the plants of one invasion are displaced
by those of the next, the interval between invasions increas-
ing with the stabilisation.

The germination of seed or spore is determined by its
viability and by the nature of the habitat. Viability depends
upon the structural characters of fruit, seed-coat and endos-
perm, and to a degree upon the nature of the protoplasm or
embryo. The first three affect the last directly, by protect-
ing the embryo against dryness, against injury due to carri-
age by water or by deglutition and, probably in some cases,
against excessive heat or cold. Hegelmeier (1873), Lohde
(1874), Bachmann ({881),and particularly Marloth (1883 : 225),
have investigated the structure of seed-coats. The latter
established the following groups, which are summarized
here somewhat fully because of their bearing upon ecesis:
(1) seed-coats without protective elements, endosperm
absent or rudimentary, Epilobium, Impatiens, Parnassia, Sag-
ittaria, etc.; (2) protective elements lacking or few, endo-
sperm highly developed with thick-walled cells, Liliaceae,
Primulaceae, Rubiaceae, etc.; (8) protective cells present in
the seed-coats, endosperm little or none, Boraginaceae, Cras-
sulaceae, Cruciferae, Labiatae, Papilionaceae, etc.; (4) protec-
tive elements present, Asclepias, Campanula, Gentiana, Silene,
Sawifraga, ete. (5) protective cells present, endosperm thick-
walled, Euonymus, Helianthemum, Ribes. The protective cells
are of various kinds: (1) epidermal cells strongly cuticular-

54 INVASION

ized, Caryophyllaceae, Crassulaceae, Fumariaceae, Saxifragaceae;
(2) parenchyma thick-walled, several-layered, Aesculus, Cas-
tanea, Fagus; (8) parenchyma cells with the inner or radial
walls thickened, Campanula, Erythraea, Gentiana; (4) epider-
mal cells cup-shaped, thick-walled, Cruciferae, Ribes, Vacci-
nium; (5) parenchyma with thickened, cellulose walls,
Geranium, Viburnum; (6) a single row of stone-cells, Labiatae;
(7) tissue of stune-cells, Hippuris, Naias, Potamogeton; (8)
elongate stone-cells, Coniferae, Cupuliferae, Euphorbia, Linum,
‘Malva, Viola; (9) short columnar thick-walled branched cells,
Cucurbitaceae, Datura, Hypericum; (10) prosenchyma with
cellulose walls, Clematis; (11) prosenchyma with lignified
walls, Fraxvinus, Rhamnus, Ranunculus. The seed-coats have
a certain influence in determining germination at the proper
time, in as much as they make it difficult for the seed to ger-
minate under the stimulus of a quantity of warmth and
moisture insufficient to support the seedling. The effect of
the endosperm, as well as that of other food-supply in the
seed, upon germination and the establishment of the seed.
ling is obvious.

The behavior of seed or spore with respect to germina-
tion depends in a large degree upon the character of the
protoplasm or embryo, though in just what way is at pres-
ent a matter of conjecture. It is evident that many seeds
are not viable because fertilisation has not been effected,
and in consequence no embryo has developed. This is the
usual explanation of the low germinating power of the seed
of some species, especially polyspermatous ones. But even
in viable seeds the behavior is always more or less irregular.
The seeds of some species will grow immediately after ripen-
ing, while others germinate only after a resting period of
uncertain duration. The same is true of spores. Even in
the case of seeds from the same parent, under apparently
similar conditions, while the majority will germinate the
first year, some will lie dormant for one or more years.
The precise reason why many seeds and spores germinate
more readily after being frozen is equally obscure. The
period of time for which disseminules may remain viable is

ECESIS 55

extremely diverse, though, as would be expected, it is much
longer as a rule for seeds than for spores. The greater
vitality of seeds in the case of ruderal plants suggests that
this diversity may be due simply to variation in the vigor of
the embryos. It would seem that under proper conditions
seeds may retain their viability for an indefinite period.

The influence of habitat upon germination is of primary
importance, though the manner in which its influence is ex-
erted is by no means as evident as might be supposed. In
the case of seeds sown in the planthouse, it is almost uni-
versally the case that germination is less than in nature,
notwithstanding the fact that temperature and moisture
appear to be optimum. In nature, the seeds of the species
may be carried into a number of different formations, any
one or all of which may present conditions unfavorable to
germination. With respect to probability of germination,
habitats are of two sorts, those which are denuded and those
which bear vegetation. It is impossible to lay down general
propositions with respect to either group, since germination
will vary with the character of the invading species, the
annual distribution of heat and moisture in the habitat, etc.
Ina general way, however, it may be stated that the chances
for germination are greater in vegetation than in denuded
areas, chiefly because the latter are usually xerophytic. On
the other hand, the lack of competition in the denuded area
tends to make ultimate establishment much more certain.
Here, as elsewhere when exact statistical results are desired,
the use of the quadrat, and especially of the permanent
quadrat, is necessary to determine the comparative germina-
tion of the invading species in relation to denudation and
vegetation.

The seedling once established by germination, the prob-
ability of its growing and maturing will depend upon its
habitat form, plasticity and vegetation-form. Even though
it may germinate under opposite conditions, a typical hylo-
phyte, such as Impatiens for example, will not thrive in an
open meadow, nor will characteristic poophytes, such as
most grasses, grow in deep shade. In the same way,

56 INVASION

xerophytes do not adapt themselves to hydrophytic habitats,
nor hydrophytes to xerophytic conditions. Many meso-
phytes, however, possess to a certain degree the ability to
adjust themselves to somewhat xerophytic or hydrophytic
situations, while woodland plants often invade either forest
or meadow. This capability for adjustment, i.e., plasticity,
is greatest in intermediate species, those that grow in
habitats not characterised by great excess or deficiency of
some factor, and it is least in forms highly specialised in
respect to water-content, shade, etc. It may then be estab-
lished as a fundamental rule that ecesis is determined very
largely by the essential physical similarity of the old and the
new habitat, except in the case of plastic forms, which admit of
a wider range of accomodation. The plasticity of a plant is
not necessarily indicated by structural modification, though
such adjustment is usually typical of plastic species, but it
may sometimes arise from a functional adaptation, which for
some reason does not produce concomitant structural
changes. The former explains such various habitat forms
of the same species as are found in Galium boreale, Gentiana
acuta, etc., and the latter the morphological constancy of
plants like Chamaenerium, which grow in very diverse
habitats. ;

The vegetation form of the invading species is often of
the greatest importance in determining whether it will
become established. The vegetation form represents those
modifications, which, produced in the original home by com-
petition,i.e., the struggle for existence, are primarily of value
in securing and maintaining a foot hold. These comprise
all structures by means of which the plant occupies a defi-
nite space in the air, through which the necessary light and
heat reach it, and in the soil, from which it draws its food
supply. These structures are all organs of duration or of
perennation, such as root, rootstalk, bulb, tuber, woody
stem, etc., which find their greatest development among
trees and shrubs, and their least among annual herbs. But
while the invaders are aided in securing possession by the
proper vegetation form, the occupation of the plant already

BARRIERS 57

in possession is increased by the same means, and the out-
come is then largely determined by other factors. To avoid
repetition, the bearing of occupation upon invasion will be
considered under succession.

BARRIERS.

DeCandolle (1820:45) seems to have been the first to use
the term barrier and to distinguish the various kinds, though
Hedenberg (1754:67) clearly saw that stations of one kind
were insurmountable obstacles to plants belonging to a very
different type. DeCandolle points out that the natural
barriers to continuous invasion (‘‘transport de proche en
proche’) are: (1) seas, which decrease invasion almost in
inverse proportion to their extent; (2) deserts; (3) mountain
ranges, which are less absolute on account of passes, valleys,
etc.; (4) vegetation, marshes being barriers to dry land
plants, forests to those that fear the shade, etc. Henfrey
{{852:56) discusses the effect of geological and climatic bar-
riers, and recognizes that man and animals often place a
limit upon the spread of plants. A. DeCandolle (1855 :70, 207)
treats of climatic barriers at considerable length, while
Darwin (1859) discusses topographical barriers in a more
general way. Grisebach (1872:4), in discussing the effect of
barriers upon the constitution of vegetation, lays down the
fundamental rule that: ‘La loi supréme servant de base &
l’établissement persistant de flores naturelles, doit donc étre
Teconnue dans les barriéres qui en ont entravé ou compléte-
ment empéché le mélange.’’ Pound and Clements (1898: 18)
distinguish the physiographical barriers in invasion as
obstructive, i. e., barriers, and conductive, agencies for
migration.

Any feature of the topography, whether physical or
biological, that restricts or prevents invasion, is a barrier.
Such features are usually permanent and produce permanent
barriers, though the latter may often be temporary, existing
for a few years only, or even for a single season. In this
last: case, however, they are as a rule recurrent. Barriers
may furthermore be distinguished as complete or incomplete
With respect to the thoroughness with which they limit

58 INVASION

invasion. Finally, the consideration of this subject gains
clearness, if it be recognized that there are barriers to migra-
tion as well as to ecesis, and if we distinguish barriers as
physical or biological with reference to the character of the
feature concerned.

Physical barriers (obices physicae) are those in
which limitation is produced by some marked physiographic
feature, such as the ocean or some other large body of water,
large rivers, mountain ranges and deserts (including ice and
snow-fields). All of these are effective by virtue of their
dominant physical factors: hence they are barriers to the
ecesis of species coming from very different habitats, but
they act as conductors for species from similar vegetation,
especially in the case of water-currents. A body of
water, representing maximum water-content, is a barrier to
mesophytic and xerophytic species, but a conductor for
hydrophytic ones: deserts set a limit to the spread of meso-
phytic and hydrophytic plants, while they offer conditions
favorable to the invasion of xerophytes; and ahigh mountain
range, because of the reduction of temperature, restricts the
extension of macrothermal and mesothermal plants. A
mountain range, unlike other physical barriers, is also an
obstacle to migration, in as much as natural distributive
agents rarely act through it or over it.

Biological barriers (obices bioticae) include vegeta-
tion, man and animals, and plant parasites. The limiting
effect of vegetation is exhibited in two ways. In the first
place, a formation acts as a barrier to the ecesis of species
invading it from the formations of another type, on account
of the physical differences of the habitats: whether such a
barrier be complete or partial will depend upon the degree
of dissimilarity existing between the formations. Hylo-
phytes are unable to invade a prairie, though open thicket
plants may do so to a certain degree. In the same way, a
forest formation on account of its diffuse light is a barrier to
poophytes, and a swamp because of the amount and char-
acter of the water-content sets a limit to both hylophytes
and poophytes. Formations, such as forests, thickets, etc.,
sometimes act also as direct obstacles to migration, as in the

BARRIERS 59.

case of tumble- weeds and other anemochores, clinochores, etc.
A marked effect of vegetation in decreasing invasion arises
from the closed association typical of stable formations and of
social exclusive species. In these, the occupation is so thor-
ough and the struggle for existence so intense that the inva-
ders, though fitted to grow under the physical factors present,
are unable to compete with the species in possession for the
requisite amount of some necessary factor. Closed associa-
tions usually act as complete barriers, while open ones
restrict invasion in direct proportion to the degree of occu-
pation. To this fact may be traced a fundamental law of
succession, viz., the number of stages ina succession is deter-
mined largely by the increasing difficulty of invasion as the
habitat becomes stabilized. Man and animals affect migra-
tion directly, though not obviously, by the destruction of
disseminules. They operate as a pronounced barrier to
ecesis wherever they alter conditions in such a way as to
make them unfavorable to invading species, or when, by
direct action upon the latter, such as grazing, tramping, par-
asitism, etc., they turn the scale in the struggle for existence.
The absence of insects adapted to insure fertilisation is some-
times a serious barrier to the establishment uf adventicious
or introduced plants. The presence of parasitic fungi, in so
far as they destroy the seeds of plants, acts as an obstacle
to migration, and restricts or prevents ecesis in so far as the
fungi destroy the invaders, or place them at a disadvantage
in. the struggle for existence.

Physical barriers are typically permanent in character,
while biological ones are either permanent or temporary,
depending upon the permanence of the formation and the
constancy of the physical factors which determine it. A
Stable formation, such as a forest,or meadow, which acts as
adecided barrier to invasion from adjacent vegetation, may
disappear completely, as a result of a land-slide, flood or
burn, or through the activity of man, and may leave an area
into which invaders crowd from every point. Often, with-
out undergoing marked change, a formation which has pre-
sented conditions unfavorable to the ecesis of species of
mesophytic character, may by reason of a temporary change

60 INVASION

in climate become sufficiently modified to permit the inva-
sion of mesophytes. On the other hand, a meadow ceases
to be a barrier to prairie xerophytes during a period of
unusually dry years. A peculiar example of the modifica-
tion of a barrier is afforded by the defoliation of aspen
forests in the mountains, as a result of which poophytes
have been enabled to invade them. Nearly all xerophytie
stretches of sand and gravel, dunes, blow-outs, gravel-slides,
etc,, and even prairies to a certain degree, exhibit a recur-
rent seasonal change in spring, as a result of which the hot
dry surface becomes sufficiently moist to permit the germi-
nation and growth of invaders, which are entirely barred out
during the remainder of the year. In an absolute sense, no
barrier is complete, since the coldest as well as the dryest
portions of the earth’s surface are capable, at times at least,
of supporting the lowest types of vegetation. Relatively,
however, in connection with the natural spread of terrestrial
plants, it is possible to distinguish partial barriers from
complete ones. Such a distinction is of importance in the
consideration of invasions from a definite region, as it is
only in this restricted sense that complete barriers have pro-
duced endemism.

Distance, though hardly to be considered a barrier in the
strict sense of the word, unquestionably plays an important
part in determining the amount of invasion. The effect of
distance is best seen in the case of migration, as it influences
ecesis only in those rare cases where viability is affected,
The importance of distance, or to take the converse, of prox-
imity, is readily ascertained by the study of any succession
from denudation. It has been established that the contig-
uous vegetation furnishes 75-90% of the constituent species
of the initial formation, and in mountainous regions, where
ruderal plants are extremely rare, the percentage is even
higher. The reason for this is to be found not only in the
fact that the adjacent species have a much shorter distance
to go and hence will be carried in much greater quantity, but
also in that the species of the formations beyond must pass

BARRIERS 61

through or over the adjacent ones. In the latter case, the
number of disseminules is relatively small on account of the
distance, while invasion through the intermediate vegeta-
tion, if not entirely impossible, is extremely slow, so that
plants coming in by this route reach the denuded area only
to find it already occupied. It is as yet impossible to give a
definite numerical value to proximity in the various invasions
that mark any particular succession. This will not be
feasible until a satisfactory method has been found for deter-
mining a coefficient of mobility, but, this once done, it will
be a relatively simple matter, not merely to trace the exact
evolution of any succession of formations, but actually to
ascertain from the adjacent vegetation the probable consti-
tution of a particular future stage.

From what has been said, it follows that the primary
effect of barriers upon vegetation is obstruction. Where the
barrier is in the pathway of migration, however, it causes
deflection of the migrant as a rule, and sets up migration in
a new direction. This is often the case when the strong
winds of the plains carry disseminules towards the moun-
tains and, being unable to cross the range, drop them at the
base, or, being deflected, carry themaway at right angles to
the original direction. The same thing happens when
resistant fruits and seeds borne by the wind fall into streams
of water or into ocean currents. The direction of migration
is changed, und what is normally a barrier serves as an

agent of dissemination.
ENDEMISM.

Wildenow (1811:98) supposed that each great mountain
range had its own peculiar species, which had wandered
down into valleys and lowlands and had produced a corres-
ponding flora. Upon this basis, wholly erroneous as it was,
he established a floral region to correspond to each principal
mountain range. Brisseau-Mirbel (1815: 582) defined indigenous
plants as those which are natural to the soil in which they
grow, and exotics as those not natural to the country inhabit-
ated; but apparently he referred only to cultivated plants.
DeCandolle (820:51) used indigenous in the sense of native

62 INVASION

to contrast with introduced, and employed the word aborigi-
nal to denote peculiar plants. The latter, as he has shown,
are due to barriers, and are of primary importance for the
limitation of floral regions, of which he distinguished twenty.
With respect to distribution, he distinguished endemic genera
and families, composed of species growing in a single
country, and sporadic genera, which are distributed over the
entire world. Schouw (823 :505) extended the use of peculiar
species in the recognition of regions, and laid down the fol-
lowing rules: ‘‘Um ein pflanzengeographisches Reich zu
bilden verlange ich von einem Theile der Erdoberfliche; 1.
dass wenigstens die Hialfte der bekannten Arten diesem
Erdtheile eigenthtimlich gehdre; 2. dass wenigstens 4 der
Gattungen entweder vollig eigenthtimlich sey oder doch
wenigstens in dem Erdtheile ein so entschiedenes Maximum
habe, dass die in anderen Erdtheilen vorkommenden Arten
nur als Reprisentanten zu betrachten sind. 38. Dass einzelne
Pfianzenfamilien gleichfalls entweder diesem Erdtheile
eigenthiimlich seyen, oder wenigstens ein entschiedenes
Maximum dort haben. Doch dirfte man wohl, selbst wo das
letztere Requisit fehlt, den Erdtheil als ein besonderes
Reich ansehen, wenn die Verschiedenheiten der Gattungen
bedeutend sind.’’ Fenzl ({833:19) proposed to replace the
word sporadic, because of its use in migration, by polydemic,
and suggested the term pandemic for truly cosmopolitan
species. Meyen (1836: 160), while he recognized the value of
Schouw’s statistical method, emphasized more particularly
the importance of physiognomy, i. e. mass, habit and dis-
tribution, in determining the divisions of vegetation, a
method already employed by Treviranus (1802:85), but with-
out success on account of the rudimentary development of
the subject.

A. DeCandolle (1855:476) rejected the terms endemic and
sporadic for reasons which do not seem very valid. He
brought together in the chapters on the delimitation and
area of species an enormous mass of facts, many of which
have a direct bearing upon endemism. Darwin (1859: 66) con-
sidered at some length the proportion of endemic species in

ENDEMISM 63

oceanic islands, in which the sea is a very obvious barrier to
migration. Kabsch (1865:551) defined endemic plants as
follows: ‘‘Es sind endemische Arten, welche da wo sie heut
noch gefunden werden, auch entstanden, und aus Mangel an
giinstigen Umstinden nicht im Stande gewesen sind, sich
weiter zu verbreiten’’. He treated the endemism of oceanic
islands in considerable detail and proposed the following
rules for the determination of endemic species: ‘‘Hndemisch
im strengsten Sinne des Wortes werden wir eine Pflanzenart
fiir einen Florenbezirk nennen:

(1) Wenn die Pflanze nur in einem bestimmten Floren-
bezirk und in keinem anderen vorkommt.

(2) Wenn die Pfianze zwar in mehreren Bezirken besteht,
in diesem einen aber ihre hervorragendste Verbreitung
findet, und dasselbst auch die grésste Zahl ihrer ihr
zunachst stehenden Verwandten hat’’;

Kabsch was the first to perceive that endemism is, from the
standpoint of phylogeny, relative and not absolute, a fact
expressed in the following postulate: ‘‘Scheilt es wahrschein-
lich zu sein, dass die Mannigfaltigkeit, die Gestaltenfiille der
Pfianzendecke unserer Erde von der Natur hauptsachlichst
nur vermége der Wanderungfahigkeit der Pflanzen hervorge-
bracht worden, so dass man behavpten kann, die Ureltern
aller gegenwartigen Pflanzenformen seien vor langerer oder
kirzerer Zeit naturalisirte Arten gewesen, aus denen dann
erst, sei es durch geschlechtliche Vermischung, sei es durch
stufenweise Umbildung im Sinne der Transmutationslehre
die Typen enstanden, die wir jetzt fiir endemisch halten
miissen.’’ Grisebach (1872:267) recognized the fundamental
relation between barriers and endemism, expressing it in the
law that, ‘““Les plantes endemiques augmentent en raison des
obstacles qui s’opposent a leur extension’’. His account of
endemism in the vegetation of oceanic islands is by far the
most exhaustive that has been made.

Engler (1879) handled the related subjects of endemism and
invasion in such a comprehensive and detailed fashion that
his work will for a long time stand unrivalled in these fields}
It practically amounts to a handbook of these subjects and is

64 INVASION

so extensive that any summary of it is impossible within the
limits of this paper. In his ‘“‘Leitende Ideen’’, Engler laid
down the following principles with reference to endemism:
“19, Aus 17 and 18 geht hervor dass in Landern von hohem
Alter, namentlich in gebirgigen Gegenden, deren Vegetation
seit langem nicht durch geologische Ereignisse volisténdig
vernichtet wurde, ein reicher Endemismus herrschen muss. ’’
“20. Endemische Formen koénnen aber auch in verhilt-
nissmassig jungen Gebieten reichlich auftreten, wenn
namlich diese Gebiete, wie die asiatischen Steppen, die
amerikanischen Prarien, oder die siidamerikanischen Pam-
pas, durch ihre Beschaffenheit nur einer beschrinkten Zahl
von Vegetationformen die néthigen HExistenzbedingungen
gewabren’’.

21. Der Unterschied zwischen alten und neuen Florenge-
bieten mit reichem Endemismus besteht gewohnilich darin,
dass in den alteren Gebieten die Artenzahl der Gattungen
eine geringere, in den neueren die Artenzahl einzelner
Gattungen gewohnlich eine sehr grosse ist.’’

Buchenau (1881:124), in dealing with the distribution of
the Juncacene, has summarized the causes of endemism in the
following brief but excellent statement: ‘‘Der Endemismus
beruht nicht allein auf der Fahigkeit irgend eines Floren-
gebietes, neue Formen hervorzubringen, sondern auch auf
der (activen oder passiven) Unmdglichkeit fir die erzeugten
Formen sich weiter zu verbreiten. Ein reiches Entsteh-
ungsgebiet kann daher ausgepragten Endemismus zeigen,
wenn seine Erzeugnisse entweder unfahig zu weiten Wande-
rungen sind, oder wenn es von uniibersteiglichen Natur-
schranken umgeben ist: der Endemismus wird dagegen ver-
wischt erscheinen, wennes den entstandenen Arten mdglich
ist, sich tiber weite Flache auszubreiten.’’ Drude (1890: 124)
has distinguished endemic plants as corresponding, when the
original continuous area of a variable species has been inter -
rupted in such a way as to form several smaller areas occu-
pied by subspeeies or new species, and as relict, when a
species originally of extensive distribution is able to main-
tain itself in a limited area only, on account of changeg

ENDEMISM 65

conditions of life. It is quite possible that relict endemics,
through the earlier invasions of the original species, may be
found in a place in which the latter did not arise: in conse-
quence, there are endemics which have arisen in their
present area, and those which have migrated to it. The
latter may often be further modified, and would then fall in
the first class. The author has further pointed out that the
concept of endemism varies with the size of the area, and
that it is inapplicable to political divisions, except when
these have natural limits. Delpino ({898:356) emphasized
the primary importance of endemism in regional limitation,
and considered the relative meaning of endemism in groups
of various rank and in regions of different extent. Pound
and Clements (1900:53) extended the concept of endemism to
cover vegetation, in such a way that one may distinguish
vegetation elements, e. g., endemic formations, as well as
floral elements.

Since its first use by DeCandolle, the term endemic has been
employed quite consistently by phytogeographers with the
meaning of ‘‘peculiar to a certain region.’’ Some confusion,
however, has arisen from the fact that a few authors have
made it more or less synonymous with indigenous and auto-
chthonous, while others have regarded it as an antonym of
exotic. In its proper sense, endemic refers to distribution,
and not to origin. Its exact opposite will be found then in
Fenzl’s term polydemic, dwelling in several regions. Indi-
genous (autochthonous) and exotic, on the contrary, denote
origin, and are antonyms, indigenous signifying native, and
exotic, foreign. As Drude has shown, endemic plants may
be either indigenous, as in the case of those species that
have never moved out of the original habitat, or exotic, as
in the much rarer instances where a polydemic species has
disappeared from its original home and from all regions into
which it has migrated except one. It is understood that not
all indigenous or exotic species are endemic. The proportion
of endemic to polydemic species is a variable and somewhat
artificial one, depending upon the size of the divisions
employed.

66 INVASION

The primary causes of endemism are two, lack of migra-
tion and presence of barriers. Since distributive agents are
practically universal, lack of migration corresponds essenti-
ally to immobility, a fact which decreases the difficulty of
ascertaining the immediate causes of endemism in any par-
ticular species. Hither immobility or a barrier may pro-
duce endemism; extremely immobile plants, for example,
liliaceous species propagating almost wholly by underground
parts, are as a rule endemic, while alpine plants and those
of oceanic islands are endemic in the highest degree, re-
gardiess of their mobility. When the two conditions act
concomitantly upon a species, endemism is almost inevit-
able. It cannot be supposed, however, that immobility or
natural barriers alone, or the concomitance of the two, must
invariably give rise to endemic species; the most immobile
plant may be carried into another region by unusual or acci-
dental agencies, or the most formidable barrier to migration
may be overcome by the intensity of an agent or through
the action of man. HEndemism is also brought about by the
modification of species: new or nascent species are as a rule
endemic. Whether they will remain endemic or not will de-
pend upon the perfection of their contrivances for dissemin-
ation and upon the presence of barriers to migration or
ecesis. Finally, as Drude was the first to point out, the dis-
appearance of a polydemic species in all regions but one,
owing to the struggle for existence or to changed physical
conditions, will result in endemism.

Endemism is readily recognized by methods of distribu-
tional statistics, applied to areas limited by natural barriers
to migration or ecesis. For political areas, it has no signi-
ficance whatever, unless the boundaries of these coincide
with barriers. It determines in the first degree the validity
of regions, though the latter are often recognized also by
the presence of barriers and by the character of the vege-
tation. Hndemism may occur in areas of vegetation of any
rank from a formation to a zone. Comparisons to be of
value, however, can be instituted only between areas of the
same order, i. e. between two or more formations, two or

ENDEMISM 67

more regions, provinces, etc. In the same way, taxonomic
groups of the same rank should be used in such compari-
sons, i. e., species should be contrasted with species, genera
with genera, and families with families, except when it is
desired to obtain some measure of the age of the vegetation
by the differentiation of the endemic phyla within it. There
will be seen to exist a fundamental correspondence between
the rank of the floral division and the taxonomic group,
though the apparent exceptions to this are still too numer-
ous to warrant its expression ina general law. Asa rule,
however, formations most frequently show endemic habitat
forms and species, more rarely endemic genera; regions and
provinces commonly exhibit endemic species and genera,
rarely endemic families, while zones and hemispheres con-
tain endemic orders as well as families. This correspon-
dence is readily seen to depend primarily upon the fact that
increased differentiation in the taxonomic sense is a con-
comitant of the increased invasion of endemic species,
measured in terms of distance and difference in habitat.

1t is too early to decide satisfactorily whether it is proper
to speak of formations as endemic. At first thought, it
would seem that all formations, with the exception of
ruderal ones, were endemic, but a study of almost any trans-
ition area between regions would seem to point to the
opposite conclusion, viz. that no formations are properly
endemic. It is equally impossible at present to distinguish
different types of endemics, such as relictae, etc., as any
such classification must await the elaboration of a method
for determining the phylogeny of a natural group of species
by an investigation of theircomparative differentiation in
connection with their migration in all directions from the
vegetation centre into new habitats. In short, it will not be
possible to make a thorough study of endemism and to
postulate its laws until modern methods of research ‘have
been extended to a much larger portion of the vegetation of
the globe. The final task of phytogeography is the division
of the earth’s vegetation into natural areas. It will be at
once evident that most plants cannot properly be called

68 INVASION

endemic until the natural regions in which they are found

have been accurately defined, a work which has barely be-

gun. In the much simpler matter of distribution, upon

which the accuracy of statistical methods depends directly,

there are few regions sufficiently well known at the present

time to yield anything like permanent results.
POLYGENESIS.

Before Darwin, the question of the origin of species at
two or more places on the earth’s surface, either simultan-
eously or successively, was merely one of single or multiple
creation, and the answer was usually determined by the bias
for or against migration. In the Crigin of Species, the ques-
tion was summarily dismissed, and migration was invoked to
explain all the phenomena of distribution. With rare ex-
ceptions, this has been the position of most botanists since
Darwin. DeCandolle (1820:52), without insisting upon the
creation of new species at a single center, seems to have
been of this opinion, as the following will indicate: “Si lon
réfiéchit maintenant a l’action perpetuelle des quatre causes
de transport de graines que je viens d’ indiquer, les eaux,
les vents, les animaux et l’homme, on trouvera, je pense,
qu’ elles sont bien suffisantes pour expliquer ce petit nombre
de végétaux qu’on retrouve semblables dans les continens
divers.’’ Schouw (1824 :{22), as an opponent of what he termed
the migration theory, must have favored the view that
species were created at two or more centres, though he
failed to express himself definitely, as the following will
show: ‘‘Ob diese Pflanzen in beiden Theilen der Erde ihre
urspriingliche Heimath haben oder nicht, ist in pflanzen-
geographischer Hinsicht gleichgiiltig.’”” Henfrey (1852:47),
discussed briefly the ‘‘opinion that species were created in
different places, at different centres, either simultaneously
or at different epochs, ‘’ but dismissed it as unsatisfactory
because of the possibility of diffusion. A, DeCandolle (1855:
1114) considered the single or multiple origin of species
merely with reference to the number of individuals of each
species originally created, reaching the conclusion that both
methods were probably to be found in nature. Darwin

POLYGENESIS 69

($859 619) rejected unconditionally the idea of polygenesis,
and sought to explain all distribution by migration, though
he admitted that this was difficult in many cases. He ex-
pressed his ideas on this subject in the following statement:
“It is also obvious that the individuals of the same species,
though now inhabiting distant and isolated regions, must
have proceeded from one spot, where their parents were
first produced: for, as has been explained, it is incredible
that individuals identically the same should have been pro-
duced from varents specifically distinct. We are thus
brought to the question, which has been largely discussed
by naturalists, namely, whether species have been created
at one or more points of the earth’s surface. Undoubtedly
there are many cases of extreme difficulty in understanding
how the same species could possibly have migrated from
some one point to the several distant and isolated points
where now found. Nevertheless, the simplicity of the view
that each species was first produced within a single region
captivates the mind. He who rejects it rejects the vera
causa of ordinary generation with subsequent migration, and
calls in the agency of a miracle.’’ Palacky (1864, Just ’89:
169) was apparently the first, after the publication of Dar-
win’s theory, to lend support to the doctrine of polygenesis,
but his work, unfortunately, is not accessible.

Kabsch (1865:552) has asserted most emphatically his
opinion that species have single centres of creation and that
they proceed from a single individual. In this connection
he has made the following statements: ‘Sede Art besitzt nur
einen Punkt auf der Erde, wo sie entstanden und von dem aus
siesich weiter verbreitet hat:es giebt nicht zwei Punkte auf
der Erde in einiger Entfernung von einander und hat es zu
keiner Zeit gegeben, wo die oft so d4usserst zarten und fir
unser Auge zum Theil noch verborgenen oder nicht erkann-
ten Lebensbedingungen, welche auf die Umbildung der
Pflanzen wirken, sich so vollkommen gleich gewesen waren,
dass dieselbe Pflanzenform an verschiedenen Punkten
zugleich hatte entstehen kénnen. Aehnliche Verhdltnisse
sind jedoch jetzt und noch mehr in friiheren Erdepochen

70 INVASION

zahlreich vorhanden gewesen; aber Aehnliches vermochte nur
Aehnliches, nie vollkommen Gleiches hervorzubringen.

: . hat die Natur uns ein untrigliches Zeugniss
aufbewahrt, dass sie selbst an verhiltnissmassig einander
nahe gelegenen Orten unter einem Klima, dass fiir unser
Wahrnehmungsvermigen wenigstens vollkommen gleichar-
tig genannt werden muss, niemals vermochte gleiche,
sondern immer nur 4hnliche Pflanzenformen zu schaffen,
dass somit unsere urspriingliche Annahme, dass _ jede
Pflanzenart nur von einem Individuum ausgegangen, eine
nicht wegzuleugnende Begriindung besitzt.”’

Nageli (1873:189) seems to have had some idea of both
polygenesis and polyphylesis, but the fact that he was not
dealing primarily with such questions makes it difficult to
decide just how clearly he perceived these relations: ‘'2.
Hine Pflanzenform A ist tiber ein grosses Gebiet verbreitet.
Innerhalb dieses Gebietes findet sich cénobitisch mit A die
verwandte Form B auf verschiedenen Standorten, welche
ihrer Lage nach eine Kinwanderung hoéchst unwahrscheinlich
und selbst unmdglich erscheinen lassen. . . . Wennes
nun sicher ist, dass die cénobitischen verwandten Formen
nicht durch spitere Wanderung zusammen gekommen sind,
so ergiebt sich die fernere Frage, ob der in ihren Merkmalen
ausgesprochene Abstand zwischen ihnen wé&hrend ihrer
Geselligkeit unverindert geblieben ist, oder ob er sich
geandert hat. Die Aenderung gestattet wieder eine dop-
pelte Moglichkeit: entweder ist der Abstand grésser oder
kleiner geworden. Entweder divergiren die beiden Formen
und miissen somit in friiherer oder spaiterer Vergangenheit
von einem gemeinsamen Ursprung ausgegangen sein, oder
die beiden Formen convergiren und werden in friherer oder
spaterer Zukunft zuasammenfliessen. (201) Hine Pflanzenform
bildet Varietaten von denen nicht nur eine sondern zwei
sich als existenzfahig erweisen, und nach zwei entgeg-
engesetzten Richtungen hin die Mutterform an Stirke
tbertreffen . . . Diese zweite Art der Speciesbildung,
die man die didymogenetische nennen kann, ist von der
ersten, der monogenetischen, nicht streng geschieden’’.

POLYGENESIS 71

Engler (1879: 318) was the first to deal concretely with the
question of multiple origin by extending his observations to
species and varieties. His conclusions seem to make the
existence of polyphylesis (as he termed it) as certain as is
possible without direct experiment. His argument is as fol-
lows: ‘‘Kann das, was man gewohnlich Art, Gattung,
Familie nennt, nur an einer Stelle oder auch an zwei Stellen
der Erde und dann selbstverstaindlich an mehreren entstehen?

Das gewisse aussere Verhiltnisse an verschiedenen
Orten eine Pflanze in gleicher Weise umgestalten kénnen
wissen wir. Es haben zwar keineswegs die fusseren
Verhialtnisse, unter denen gewohnlich eine bestimmte Var-
ietit b existiert, sofort die Umwandlung einer andern
Varietait @ derselben Art in die Varietaét b zur Folge: aber
diese Umwandlung kann bei den Descendenten und zwar an
verschiedenen Stellen eintreten. NNehmen wir nun an, eine
Art A habe in der Natur im Laufe der Zeit ein grésseres
Verbreitungsareal gewonnen, so ist es nach Obigem méglich
dass dieselbe an zwei von einander entfernten Stellen m und
nm, welche annaherend gleiche Bedingungen gewiahren,
dieselbe Varietéat a erzeugt. Praktisch haben wir solche
Falle ganz besonders bei Hochgebirgspflanzen wo sehr oft
das Areal der hdheren Regionen Raum bietet fiir die
Varietiten, welche sich aus einer Art entwickeln, dass die
gréssere Areal der nachst tieferen Region einnimmt.
Somit kénnen also schliesslich Gattungsgruppen in entfern-
teren Gebieten entstehen, welche doch zu einander in einer
gewissen verwandtschaftlichen Beziehung stehen.
Nach diesen Erwagungen stehe ich nun nicht an, mich zur
Lehre von der Einheit des Ausgangspunktes einer Gattung
zu bekennen, jedoch eben nur der natiirlichen Gattungen’’.
Drude (1886:200) accepted the doctrine of the multiple
origin of major groups, but he did not extend it to species
and varieties. Finally, Delpino (1898:6) has expressed him-
self very definitely against the multiple origin of species:
“Per ogni specie stabilmente concretata e fissa io credo
doversi ammettere un centro di formazione ed uno soltanto.
E veramente, considerando l’infinita fluttuazione delle forme

i

72 INVASION

organiche, ammettere che la stessa identica species possa
essersi attuata e concretata in tempi diversi, e in due o pit
luoghi distinti, é tale improbabilité che confina coll’ assurdo.
Se ogni specie deve ritenersi come il prodotto d’un immenso
numero di fenomeni antecedenti, eome l’effero di una quasi
infinita quantitd di adattamenti ad un ambiente infinitamente
mutevole, come pué un cosifattamente complicato prodotto
essersi ripetuto e manifestato due o pit volte, in due o pit
tempi distinti, in dueo pid luoghi separati? Una cotal
congettura accettata da Grisebach e da altri, é per me
assurda. Io mi ribello contro essa’’.

The idea of polyphylesis, as advanced by Engler, contains
two distinct concepts: (1) that a species may arise in two
different places or at two different times from the same
species, and (2) that a genus or higher group may arise at
different places or times by the convergence of two or more
lines of origin. It is here proposed to restrict polyphylesis,
as its meaning would indicate, to the second concept, and to
employ for the first the term polygenesis, first suggested
by Huxley in the sense of polyphylesis. The term polyphy-
lesis is extended, however, to cover the origin of those
species which arise at different places or times from the
convergence of two or more different species, a logical exten-
sion of the idea underlying polyphyletic genera, though it
may seem at first thought tobe absurd. Polygenesis may be
formally defined as the origin of one species from another
species at two or more distinct places on the earth’s surface,
at the same time or at different times, or its origin in the
same place at different times. Polyphylesis, on the
contrary, is the origin of one species from two or more dif-
ferent species at different places, at the same time or at
different times. It is evident that what is true of species in
this connection will hold equally well of genera and higher
groups. Opposed to polygenesis is monogenesis, in which a
species arises but once from another species; with polyphy-
lesis is to be contrasted monophylesis, in which the species
arises from a single other species. It will be noticed at
once that these two concepts are closely related. The

POLYGENESIS 73

following diagrams will serve to make the above distinctions

more evident:

I, Polygenesis II. Polyphylesis IIL. Monogenesis
(Monophylesis)

a { 8 @ @Q

y n
™ m™m x ¢ ae P
|.

a a c a b c!
In I, a species A, becomes scattered over a large area in a

series of places, m . . . m=, with the same physical factors,

in any or all of which may arise the new species a. In II,
a species with xerophytic tendency, 4, and one with meso-
phytic tendency. B, in the course of migration find them-
selves respectively in a more mesophytic habitat, m, and a
more xerophytic one, x, in which either may give rise to the
new form, c, which is more or less intermediate between A
and B, Ia III, the method of origin is of the simplest type,
in which a species is modified directly into another one, or
is split up into several.

In affirming the probability of a polygenetic origin of
species, there is no intention of asserting that all species
originate in this way. It seems evident that a very large
number of species of restricted range are certainly mono-
genetic, at least as far as origin in space is concerned: it is
possible that any species may arise at two or more distinct
times. Polygenesis can occur readily only in species of
more or less extensive area, in which recur instances of the
same or similar habitat. The relative frequence and

74 INVASION

importance of the two methods can hardly be conjectured as
yet, but origin by monogenesis would seem to be the rule.

The arguments adduced by Engler in support of poly-
genesis are in themselves conclusive, but the investigations
of the past decade have brought to light additional proofs,
especially from the experimental side. In determining the
physical factors of prairie and mountain formations, and
especially by methods of experimental ecology, the author
has found that habitats are much less complex than they are
ordinarily thought to be, since water-content and humidity,
and to a less degree light, constitute the only factors which
produce direct modification. In addition, it has been ascer-
tained that the minimum difference of water-content, hu-
midity or light, necessary to produce a distinguishable
morphological adjustment, is much greater than the unit
differences recorded by the instruments. In short, the
differences of habitats, asascertained by thermograph, psy-
chrometer and photometer, are much greater than their
efficient differences, and, with respect to their ability to pro-
duce modification , habitats fall into relatively few categories.
A striking illustration of this is seen in the superfi-
cially very different habitats, desert, strand, alkali plain,
alpine moor, and arctic tundra. all of which are capable of
producing the same type of xerophyte. It follows from this
that many more or less plastic species of extensive
geographical area will find themselves in similar or identical
situations, measured in terms of efficient differences, and
will be modified in the same way in two or more of these.
In mountain regions, where interruption of the surface and
consequent alternation are great, the mutual invasion of con-
tiguous formations is of freauent occurrence, often resulting
in habitat forms.' The spots in which these nascent species,
such as Galium boreale hylocolum, Aster levis lochmocolus, etc.,
are found, are often so related to the area of the parent
species as to demonstrate conclusively that these forms are
the result of polygenesis and not of migration. Naturally,

1Clements, F. E. A System of Nomenclature for Phytogeography.
Engler 31:b 17 1902.

POLYGENESIS 75

what is true of a small area will hold equally well of a large
region, and the recurrence of the same habitat form may be
accepted as conclusive proof of polygenesis. The most
convincing evidences of multiple origin, however, are to be
found in what De Vries has called ‘‘mutations’’. It makes
little difference whether we accept mutations in the exact
sense of this author, or regard them as forms characterised
by latent variability. The evidence is conclusive that the
same form may arise in nature or in cultivation, in Holland
or in America, not merely once, but several or many times.
In the presence of such confirmation, it is unnecessary to
accumulate proofs. Polygenesis throws a new light upon
many difficult problems of invasion and distribution, and, as
a working principle, admits of repeated tests in the field.
It obviates, moreover, the almost insuperable difficulties in
the way of explaining the ‘distribution of many polygenetic
species on the basis of migration alone.

In 1898, the author first advanced a tentative hypothesis
to the effect that a species homogeneous morphologically
may arise from two distinct though related species: during
subsequent years of formational study, the conviction has
grown in regard to the probability of such a method of
origin. Since the appearance of Engler’s work, a polyphy-
letic origin for certain genera has been very generally ac-
cepted by botanists, but all have ignored the fact that the
polyphylesis of genera carries with it the admission of such
origin for species, since the former are merely groups of the
latter. I cannot, however,agree with Engler, that polyphylet-
ic genera, and hence species also, are necessarily wanatural.
If the convergence of the lines of polyphylesis has been
great, resulting in essential morphological harmony, the
genus is a natural one, even though the ancestral phyla may
be recognizable. If, on the other hand, the convergence is
more or less imperfect, resulting in sub-groups of species
more nearly related within the groups than between them,
the genus can hardly be termed natural. This condition
may, however, prevail ina monophyletic genus with mani-

76 INVASION

fest divergence, and still not be an indication that it is arti. :
ficial. S
Darwin (1859 :186), in speaking of convergence, says: “Tf
two species belonging to two distinct though allied genera,
had both produced a large number of new and divergent
forms, it is conceivable that these might approach each
other so closely that they would have all to be classified
under the same genus: and thus the descendants of two dis-
tinct genera would converge into one.’? The application of
this statement to species would at once show the possibility
of polyphylesis in the latter, and a further examination of
the matter will demonstrate its probability. Itis perfectly
evident that a species may be split into two or more forms
by varying the conditions, let us say of water-content, and
that the descendants of these forms may again be changed
into the parent type by reversing the process. This has, in
fact, been done experimentally. Since it is admittedly im-
possible to draw any absolute line between forms, varieties
and species, it is at once clear that two distinct though re-
lated species, especially if they are plastic, may be caused
to converge in such a way that the variants may constitute
anew and homogeneous species. This may be illustrated
by a concrete case at present under investigation. Kuhn-
istera purpurea differs from K. candida in being smaller, in
having fewer, smaller and more narrow leaflets, and a
globoid spike of purple flowers in place of an elongated one
of white flowers; in a word, it is more xerophytic. This
conclusion is completely corroborated by its occurrence.
On dozens of slopes examined, Kuhnistera purpurea has never
been found mingling with K. candida on lower slopes, except
where an accident of the surface has resulted in a local de-
crease of water-content. The experiment as conducted is a
simple one, consisting merely in sowing seed of each in the
zone of the other, and in growing K. purpurea under con-
trolled mesophytic conditions, and K. candida under simil-
arly measured xerophytic conditions in the plant house.
While the polyphyletic origin of species is in a fair way to
be decided by experiment, it receives support from several

KINDS OF INVASION 77

well-known phenomena. The striking similarity in the
plant body of families taxonomically so distinct as the
Cactaceae, Stapeliaceae, and Euphorbiaceae, or Cyperaceae and
Juncaceae, indicates that a vegetation form may be polyphy-
letic. On the other hand, the local appearance of zygo-
morphy, of symphysis, and of aphanisis in the floral types of
phylogenetically distinct families is a proof of the operation
of convergence in reproductive characters. To be sure, the
convergence is never so great as to produce more than
superficial similarity, but this is because the groups are
markedly different in so many fundamental characters: the
same tendency in closely related species would easily result
in identity. As in the case of polygenesis, the relatively
small number of typically distinct habitats makes it clear
that two different species of wide distribution, bearing to
each ‘other the relations of xerophyte to mesophyte, of
hydrophyte to mesophyte, or of poophyte to hylophyte,
might often find themselves in reciprocal situations, with the
result that they would give rise to the same new form. The
final proof of the polyphylesis of species is afforded by the
experiments of De Vries in mutation. De Vries found that
Oenothera nanella arose from O. Lamarckiana, O. laevifolia, and
0. scintillans: Oenothera scintillans arose from O. lata and
0. Lamarckiana; Oenothera rubrinervis from O. Lamarckiana,
0. laevifolia, O. lata, O. oblonga, O. nanella and O. scintillans,
etc. Whatever may be the rank assigned to these mutations,
whether form, variety or species, there can be no question of
their polyphyletic origin, nor, in consequence of the con-
nection of mutations with variations through such incon-
stant forms as O. scintillans, O. elliptica and O. sublinearis, of
the possibility of polyphylesis in any two distinct though
related species or genera.
KINDS OF INVASION.

With respect to the frequency of migration, we may dis-
tinguish invasion as continuous (invasio continua), or
intermittent (invasio infrequens). Continuous invasion,
which is indeed usually mutual, occurs between contiguous
formations of more or less similar character, in which there

48 INVASION

is an annual movement from one into the other, and at the
same time a forward movement through each, result-
ing from the invaders established the preceding year. By
far the greater amount of invasion is of thissort, as may
readily be seen from the fact that migration varies inversely
as the distance, and ecesis may decrease even more rapidly
than the distance increases. The significant feature of con-
tinuous invasion is that an outpost may be reinforced every
year, thus making probable the establishment of new
outposts from this as a centre, and the ultimate extension of
the species over a wide area. Thecomparatively short dis-
tance and the regular alternation of migration and ecesis
render invasion of this sort very effective. An excellent
illustration of this is seen in transition areas and regions,
which are due directly to continuous and usually to mutual
invasion. Intermittent invasion results commonly from
distant carriage, though it may occur very rarely between
dissimilar adjacent formations, when a temporary swing in
the physical factors makes ecesis possible for atime. It is
characterised by the fact that the succession of factors
which have brought about the invasion is more or less acci-
dental, and may never recur. Intermittent invasion is
relatively rare, and from the small number of disseminules
affected, it is of little importance in modifying vegetation
quantitatively. On the other hand, since a species may often
be carried farfrom its geographical area, it is frequently of
great significance in distribution.

When the movement of invaders into a formation is so
great that the original occupants are finally driven out, the
invasion may be termed complete (invasio perfecta). Such
invasion is found regularly in thecase of many ruderal for-
mations, and is typical of the later stages of many suc-
cessions. Jt isordinarily the result of continuous invasion.
If the number of invaders is sufficiently small that they may
be adopted into the formation without radically changing the
latter, the invasion is partial (invasio imperfecta). Thisis
doubtless true ofthe greater number of invasions, though

KINDS OF INVASION 79

these are regularly much less striking and important than
instances of complete invasion.

The permanence of invasion depends upon the success at-
tending ecesis, and upon the stability of the formation. It
has already been noticed that under certain conditions
plants may germinate and grow, and, if they are perennials,
even become established, and still ecesis be so imperfect.
that reproduction is impossible. Others may find the con-
ditions sufficiently favorable for propagation, but unfavor-
able for the formation of flowers and fruits. Finally, there
are plants which seem to be perfectly established for a few
years, only to disappear completely. The latter are ex-
amples of temporary invasion (invasio temporalis).
It is necessary to draw clearly the line between complete
and partial invasion in this connection. The former is tem-
porary in the initial or intermediate stages of nearly all suc-
cessions, as compared with the ultimate stages, though it is
in a large degree permanent in comparison with the partial
invasion of species which are able to maintain themselves
fora few years. In a sense, there is a real distinction be-
tween the two, inasmuch as a particular stage of succession
is permanent as long as the habitat remains essentially the
same: a critical study of the species of such stages shows,
however, that they manifest very different degrees of per-
manence. Species which invade stable vegetation tempor-
arily have been termed adventive by A. DeCandolle (1855:
643). Permanent invasion (invasio diutina) occurs
when a species becomes permanently established in a more
or less stable formation. It is characteristic of the great
majority of invaders found in the grassland and forest stages
of successions.

Plants which have arisen within a formation or have been
a constituent part of it since its origin are indigenous
(species indigenae). Contrasted with these are the species
which have invaded the formation since it received its dis-
tinctive impress: these are derived (species derivatae sew
advenae). The determination of the indigenous and derived
species of a formation or larger division is of the utmost im-

80 INVASION

portance, as it enables us to retrace the steps by which the
formation has reached its present structure, and to recon-
struct formations long since disappeared. To render it less
difficult, it is necessary to scrutinize the derived elements
closely, first, because it is easiest to recognize the indigenous
species by eliminating the derived, and second, because this
analysis will show that not all derived species have entered
the formation at the same time and from the same sources.
Watson (1847:63) distinguished plants as colonist, alien, den-
‘izen and native, the last corresponding to indigenous.
Colonists are weeds of fields and wastes, rarely found out-
side of places modified by man; aliens are plants which,
though now more or less established, have been certainly
or presumably introduced from foreign counries, while den-
izens are species which maintain themselves as though in-
digenous, but are suspected of being introduced. A. De-
Candolle (1855:643) made the following division: (1) advent-
ive, of foreign origin, but only temporarily established; (2)
naturalized, established but certainly of foreign origin; (3)
probably foreign; (4) possibly foreign; (5) indigenous, of
undoubted native origin. Pound and Clements (1900:52) dis-
tinguished regional elements as proper (indigenous), de-
rived, and adventicious. Neither of these three groupings
gives perfectly definite and consistent divisions, and for this
reason the following arrangement is proposed. With res-
pect to their original formation or region, species are
either indigenous, native. or derived, foreign. Derived
species may be termed vicine (species vicinae), when they
are fully established invaders from adjacent formations or
regions, and adventicious (species adventiciae), when they
have come from distant formations and have succeeded in
establishing themselves. Finally, those derived species
which are unable to establish themselves permanently are
adventive (species adventivae).
THE MANNER OF INVASION.

Since the ecesis of invaders depends in large measure up-
on the occupation of the plants in possession, the method
and degree of invasion will be determined by the presence

THE MANNER OF INVASION 81

or absence of vegetation. Areas without vegetation are
either originally naked (areae nudae) or denuded (areae
denudatae), while vegetation with respect to the degree of
occupation is open (sporadophytia), or closed (pycnophytia).
Each type of area presents different conditions to invaders,
largely with respect to the factors determining ecesis.
Naked habitats, rocks, talus, gravel-slides and dunes, while
they offer ample opportunity for invasion on account of
the lack of occupation, are really invaded with the greatest
difficulty, not only because they contain originally few or no
disseminules, but also because of their xerophytic character
and the difficulty of obtaining a foothold, on account of the
extreme density or instability of the soil. Denuded habitats,
blowouts, sanddraws, ponds, flood plains, wastes, fields and
burns, usually afford maximum opportunity for invasion.
They invariably contain a large number of disseminules
ready to spring up as soon as the original vegetation is des-
troyed; the surface, moreover, is usually such as to catch
disseminules and to offer them optimum conditions of mois-
ture and nutrition. Open formations are readily invaded,
though the increased occupation renders entrance more
difficult than it is in denuded areas. Closed formations, on
the other hand, are characterised by a minimum of in-
vasion, partly because invaders from different formations
find unfavorable conditions in them, but chiefly because the
occupation of the inhabitants is so complete that invaders
are unable to establish themselves.

Invasion takes place by the penetration of single individ-
uals or groups of individuals. This will depend in the first
place upon the character of the disseminule. It is evident
that, no matter how numerous the achenes may be, the
invasion of those anemochorous species with comate or
winged seeds or one-seeded fruits will be of the first type,
while all species in which the disseminule is a several or
many-seeded fruit or plant, as in hooked fruits, tumble-
weeds, etc., will tend to pruduce a group of invaders.
Occasionally of course, the accidents of migration will bring
together a few one-seeded disseminules into a group, or will

82 INVASION

scatter the seeds of a many-seeded fruit, but these constitute
relatively rare exceptions. This distinction in the matter of
invasion is of value in studying the relative rapidity of the
latter, and the establishment of new centres, but it is of
greatest importance in explaining the historical arrange-
ment of species in a formation, and hence has a direct
bearing upon alternation. It is entirely independent of the
number of invaders, which, as we have seen, depends upon
seed-production, mobility, distance, occupation, etc., but is
based solely upon mode of arrangement, and will be found
to underlie the primary tyves of abundance, copious and
gregarious. In this connection, it should also be noted that
the contingencies of migration, especially the concomitant
action in the same direction of two or more distributive
agencies, often results in the penetration of a group of indi-
viduals belonging to two or more species. This may well be
termed mass invasion (invasio solida): it is character-
istic of transition areas or regions and, along valleys or
other natural routes for migration, it gives rise to species
guilds (Artengenossenschaften, Drude). The movement of
species guilds constitutes one of the most complex and inter-
esting problems in the whole field of invasion, the solution
of which can be attempted only after the thorough analysis
of the simpler invasions between formations. A better
understanding of the meaning of invasion by species guilds
is imperative for the natural limitation of regions, as at
present such groups constitute alien associations in many
regions otherwise homogeneous.

The invasion of a formation may occur at three different
levels: (1) at the level of the favies, (2) below the facies, (8)
above the facies, depending directly upon the relative
height of invaders and occupants. The invasion level is an
extremely simple matter to determine, except in the case of
woody plants, such as shrubs and trees, which attain their
average height oniy after many years. Its importance is
fundamental: the level at which invasion occurs not only
determines the immediate constitution of the formation,
whether its impress shall still be given by the occupants, or

THE MANNER OF INVASION 83

by the invaders or by both together, but it also decides the
whole future of the formation, i. e. whether the invaders or
occupants shall persist unmodified or modified. The prob-
lem is an extremely complex one, but the careful analysis of
invasion at each level throws a flood of light upon it The
entrance of invaders of the same general height as the facies
of a formation results regularly in mixed formations. This
is well illustrated by the structure of the transition areas
between two formations of the same category, i. e. forests,
meadows, etc. It is seldom, however, that the facies and
invaders are so equally matched in height and other qualities
that they remain in equilibrium for a long period: one or the
other has a slight advantage in height, or the one suffers
shading or crowding better than the other, is longer-lived
or faster-gruwing, with the result that invader yields to
occupant, or occupant to invader. It is a well known fact
that many mixed formations represent intermediate stages
of development.

Invasion at a level different from that of the facies is in-
evitably followed by modification. If the invasion takes
place below the facies, the invaders will be exterminated
gradually, or slowly assimilated. In either case, there is
little structural change in the formation, and its stability 1s
affected slightly or not at all. If the invaders overtop the
facies in anv considerable number, the entire formation
undergoes partial or cumplete modification, or in extreme
cases it disappears, as is typically the case in succession. A

. peculiar variation of invasion at a level above the facies is
seen where woody plants invade grassland, when the trees
or shrubs become more or less uniformly scattered in an
Open woodland or open thicket. Here the grassland takes
on an altogether different appearance superficially, though
itis usually unchanged, except beneath and about the in-
vaders, where either adaptation or extermination results.
Finally, it should be borne in mind that the invasion of a
particular formation, especially in the case of layered
thickets and forests, often takes place at two levels, at the
height of the facies and below the facies.

84 INVASION

The investigation of invasion furnishes the basis for all
developmental and structural study of vegetation. Obser-
vational methods, though of great value in indicating the
causes, direction, rapidity, amount and results of invasion,
are in themselves insufficient, and must at present be sup-
plemented and in time replaced by experimental methods.
For this purpose, the writer has extended the application of
the quadrat, the use of which was first suggested by Pound
and Clements (1898:59) for the accurate determination of abund-
ance. In this connection, the quadrat is now used experi-
mentally to follow in an exact and minute manner the
changes produced by invasion. The permanent quadrat
makes it possible to revord from year to year the incidental
invasions on any one spot, or the changes of a succession as
the latter passes from one stage to another. Ifa quadrat
list showing the annual increase or decrease in abundance
of each species is all that is desired, the list quadrat, which
is five meters square, is sufficient. A permanent record of
the exact changes in a quadrat area is of much greater
value, however; such a record is obtained by the use of the
chart quadrat. The size of the latter depends upon the
character of the vegetation: in open formations, and in
forests and thickets without dense undergrowth, the chart
quadrat should be two meters square, but in closed vege-
tation the accurate plotting of a quadrat is an arduous task,
and the area best adapted to this work is a meter square.
The permanent record of a chart quadrat is made upon centi-
meter plotting paper, the scale being one centimeter to each
decimeter, and a close-focus photograph is also made of each
quadrat charted. In practice, chart quadrats have been
made permanent by driving a properly labelled stake at the
north east curner of the quadrat.

An invaluable aid to the study of invasion and succession
is the experimental or denuded quadrat. A chart quadrat
is staked out and plotted in the usual way, and a photograph
is made of it. The area is then completely denuded, especial
care being taken to remove all perennial parts. Such de-
nuded quadrats are then charted and photographed each

THE MANNER OF INVASION 85

succeeding year or season, until the area has again become
stabilised. Denuded quadrats are of great value in deter-
mining the comparative mobility and ecesis of the species of
a formation or patch, and they are indispensable for the re-
construction of the early stages of a succession.

A device known as the migration circle is employed to
study the amount, direction, and rapidity of movement away
from any particular group of individuals, which is essenti-
ally a miniature vegetation centre. The circle is used in
place of the quadrat, because it is probable that migration
will operate in all directions. The migration circle, like the
quadrat, may be either temporary or permanent: the latter,
which gives by far the more valuable results, is secured by
driving a properly labelled stake in the midst of the par-
ticular plant group, and recording the radius of the area.
The size of the circle varies with the height and mobility of
the species studied; the most satisfactory circles are those
with one, five or ten-meter radius. The twenty-five meter
circle is useful at the margin of denuded areas and in very
open vegetation, but the area enclosed is so large as to make
it impracticable in closed formations. The choice ofa circle
depends upon the size of the nucleus of individuals taken as
a center and upon the distance between two or more
adjacent centers. Because of the large area to be cleared,
it has not been found feasible to use denuded circles with a
radius larger than one meter. The value of a denuded circle
ten meters in radius for the comparative investigation of
migration and ecesis would be so great, however, that its
use is certain, as experimental methods in the field come to
be recognized as more and more imperative.

86

1745
1751
1802
1805

1811

1815

1819

1820

1823

1832
1833

1836

1843

1847

1848

1852
1855

INVASION
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Grisebach, A. Die Vegetation der Erde

Nageli, C. Das gesellschaftliches Entste-
hen neuer Species Bot.
Mitth. 3:365

Engler, A. Versuch einer Entwicklungs-
geschichte der Pflanzenwelt

Drude, O. Die systematische und geog-
raphische Anordnung der
Phanerogamen

Delpino. F. Studi di geografia botanica
secondo un nuovo indirizzo
Mem. R. Accad. Sci. V.
7 :829

DeVries, H. Die Mutationstheorie

91
SUCCESSION.

In tracing the ‘historical development of the principle of
succession, a difficulty constantly arises because of an un-
avoidable tendency to interpret the statements of earlier
authors in the light of later knowledge. Previous to 1880,
relatively few observations of the operation of this principle
had been made, and these were more or less incidental, ex-
cept in the case of some writers upon forestry, who made
no endeavor to connect the process with phytogeography.
The first recorded mention of succession seems to have been
that of Biberg ($749:78), who indicated in a very general way
the changes of vegetation on rocks from the initial lichens
to the ultimate forest. DeCandolle (1820:27), in discussing
the struggle for existence, spoke of the cultures of the dunes
of the ‘‘Landes’’, in which the rapidly growing Genista,
after having served as a ‘‘cover’’ for seedlings of Pinus, was
finally driven out by the latter. The first use of the term
succession was by Steenstrup in studying the changes of the
forest vegetation of Zealand (fide Grisebach (1844:16). Berg
(1844) studied the successive modifications of the deciduous
forests of the Harz in connection with their gradual disap-
pearance ‘before the pines. Humboldt (1850:10) evidently
recognized the presence of succession in vegetation, though
he mentioned it but incidentally: ‘‘All sea coasts afford evi-
dence of the hundreds, or even thousands of years, which
must pass before the moving sand can yield a firm basis for
the roots of herbaceous plants in those hot and rainless
regions where neither Lecideae nor other lichens can grow.’”’
‘In northern regions, the absence of plants is compensated
for by the covering of Baeomyces roseus, Cenomyce rangiferin-
us, Lecidea muscorum, Lecidea icmadophila, and other crypto-
gamia which are spread over the earth and which may be
said to prepare the way for the growth of grasses and other
herbaceous plants. In the tropical world, where mosses and
lichens are only observed to abound in shady places, some
few oily plants supply the place of the lowly lichen’’(125).

92 SUCCESSION

‘Thus one organic tissue rises, like strata, over the other
and as the human race in its development must pass through
definite stages of civilisation, so also is the gradual distri-
bution of plants dependent upon definite physical laws. In
spots where lofty forest trees now rear their towering sum-
mits, the sole covering of the barren rock was once the
tender lichen: the long and immeasurable interval was filled
up by the growth of grasses, herbaceous plants and shrubs.’’

(214)
Henfrey (1852:56) has dealt briefly with the changes in
vegetation due to the influence of man: “It is certain that

the appropriate stations of many plants would be de-
stroyed with the removal of forests, and new conditions of
soil created for the habitation of immigrants from other
regions. But the modification of the surface so as to alter
the physical condition of the soil, is by far the most im-
portant change brought about in reclaiming land for culti-
vation. The banking out of the sea changes by degrees the
vegetation of its shores: bare sand-dunes, where scarcely a
plant could maintain a precarious footing, are by degrees
covered by vegetation: sandy inland wastes are rescued from
the heath and firs, and made to contribute at first by Con-
iferous woods, such as the larch and when the soil has be-
come by degrees enriched, by the plants requiring a better
nourishment, to the general stock of wealth; and in these
changes many species are destroyed, while others naturally
making their way into a fitting station, or brought unde-
signedly by the hand of man, grow up and displace the orig-
inal inhabitants.”’ Vaupell (185!:12) confirmed the earlier
observations of Steenstrup on the Danish forest in general,
but determined the succession to be Pinus, Quercus, Betula,
Fagus. A. DeCandolle (1855:472) cited the observations of
de la Malle (1848) and Maguy (1850) upon the succession of
different forest formations in France and Germany, but he
failed to perceive the essential identity of this phenomenon
with what takes place when a forest is cut or burned down,
for he mentions the latter only to insist upon the difference
between the two. He further held the erroneous idea that

HISTORICAL 98

such changes were peculiar to social species, and hence con-
cerned only a few plants and only certain localities or
countries. Hoffmann (1856:189) found the raspberry to be
the first invader in burns in the Ural Mountains: this was
followed successively by the service-berry, alder, birch, and
other deciduous trees, and these were finally replaced by the
pines and other conifers. Hilf was apparently the first to
call attention to a general law of succession in burns or cut-
tings, viz., that the second growth 1s always of genera dif-
ferent from those found in the original vegetation. Stossner
(1859), according to Drude (1902:15), described in a detailed
manner the conversion of a fallow field covered with blue
and yellow pansies into a mountain meadow.

Middendorff (1864:641) recognized the wide occurrence
of succession (‘‘Wechselfolge’’), but considered the uulike-
ness of the different stages which had been noted by Hill to
be exceptional to the general rule. ‘Hs traf sich gerade,
dass, wo ich im Bereiche der grossen Urwaldungen Gelegen-
heit hatte altere Brandstatten und das Emvporschiessen
neuen Waldes auf ihnen zu beobachten, ich fast ausschliess-
lich die friiheren Nadelholzarten von Neuem dieselben
Flecken bedecken sah. Kiefern, Liarchen, siberische
Edeltannen sah ich in schénstem Schlusse, nicht selten in
véllig ungemischten Bestanden als schlanken Stangenwald
aus der Asche ihrer Vater hervorgehen, und das selbst dort,
wo in den umliegenden Waldern Birken sich gern einges-
prengt zeigten.

‘‘Betrachten wir also die Sache naher, so ergibt sich, dass
keineswegs die jetzt vielberufene Wechselwirthschaft der
Natur in Betreff der Waldungen vorwaltend herrscht, son-
dern vielmehr dass Gegentheil. Wie sollte dem auch anders
sein? Findet man denn nicht sogar dieselben Graser und
Blumen, findet der Botaniker uicht seine Seltenheiten stets
an demselben Orte wieder? Hs liegt keineswegs in der
Natur der Dinge, dass ein solcher Wechsel der Baumarten
stattfinden mtsse. Hine jede Baumart macht gewisse
Anspriiche an den Boden, den Untergrund, die Feuchtigkeit,
an Licht, an den Schutz, sowohl vor Wind und Wetter als

94 SUCCESSION

vor Sonnenschein, vor tiberwuchernden Pflanzen und ‘der-
gleichen mehr. Hine jede Baumart gedeiht und vermehrt
sich, alle anderen verdrangend, bis zur Alleinherrschaft,
dort wo sie ihr eigenthiimlichen Ansprtiche am best zu
befriedigen vermag.

‘Will ich etwa damit sagen dass dort wo jetzt Urwilder
stehen, auch schon seit Jahrtausenden stets dieselben
Baumarten in regelmiassig auf einander folgenden Genera-
tionen sich ausgeséiet haben, aufgewachsen sind, alterten,
vermoderten, wiederum aufwuchsen? Wenn es sich darum
behandelt, eine Regel aufzustellen, so diirfte, glaube ich,
diess allerdings im Urzustande die Regel sein, namich fir
Nord-Asien und Nord-Europa. Wie erklaren sich aber dann
die hiufigen Ausnahmen, die man beobachtet? Ich schreibe
sie vorztiglich dem Eingriffe des Menschen in das Getriebe
der Natur zu.”’

Kabsch (1865 :75) pointed out the primary réle of lichens
in the origination of succession on rock surfaces: ‘‘Die
Flechten sind die wahren Pioniere der Vegetation, sie
graben sich in den weichen Kalk wie in den hiartesten
Basalt, zersetzen das Gestein und mischen die befreiten
Bestandtheile desselben mit ihren eigenen Zersetzungs-
produkten, um so in der Vereinigung von organischem und
unorganischem Material die Méglichkeit zum Gedeihen einer
hodheren Pflanzenvegetation vorzubereiten.’’ Engler (1879: IX)
has written a comprehensive treatise upon the great suc-
cessions of the past, but these can, of course, be painted
only in the large, and have in consequence only a remote
connection with the changes of present successions. Hult
(1881, 1885) was the first to investigate succession in a sys-
tematic fashion, and to him also belongs the credit of having
laid down the general principles upon which the develop-
mental study of formations must be based. He recognized
the fundamental fact that most formations are merely tran-
sition stages to a few ultimate formations. He has traced
the developmental history of each type of intermediate
formation through its successive stages in his region, and
has studied the substitution of facies in the ultimate forests.

HISTORICAL 95

In 1887, Hult investigated the invasion and substitution of
one formatiou by another in the alpine regions of Lapp-
mark. He found that in the dryer places Cladineta and
Alectorieta finally replaced all other associations, while in
moist places grass and herbaceous formations passed into
formations of dwarf shrubs, the universal rule being a
transition from hygrophilous to more or less xerophilous
conditions.

Treub (1888), after the destructive eruption of Krakatau in
1883, found that Cyanophyceae were the first plants to appear
on the new soil: these were followed by an exclusive vege-
tation of ferns, in which a few phanerogams, especially
composites, began to appear by the third year. Senft (1888)
traced the development of vegetation on naked xerophytic
slopes of the Hérselbergen. The pioneers were lichens,
especially Parmelia, followed soon by mosses, Hypnum, Bar-
bula, and after a few years by Festuca ovina, which appeared
first in the rock clefts and then spread into a thick sod.
The next invaders were all grasses, Koeleria cristata, Briza,
Melica, and Brachypodiwm, which almost entirely replaced
Festuca in three years: the grasses were then invaded,
though not completely replaced, by herbs, Helianthemum,
Verbascum, Lactuca scariola, Agrimonia eupatoria, Anemone,
Gentiana, etc., and by a few shrubs, Juniperus communis,
Viburnum lantana, and Crataegus. Later appeared Ligustrum,
Cornus and Rhamnus, and still later, Cotoneaster, Crataegus,
Prunus and Rosa, forming a thicket twelve years after the
inception of the succession. The last stage was a forest of
Sorbus, Corylus. Fagus, Alnus, Tilia and Acer. Krassnoff
(1883, 1886) found that forest clearings in the Altai were
recovered partly by persistent forest plants, and partly by
invading steppe plants, Paeonia, Bupleurum, Aconitum, Chamae-
nerium, Delphinium, Geraniwm, Thalictrum, etc. In certain
places where fire had destroyed the forest growth, the
ground was still covered after a lapse of many years with a
tall herbaceous growth of Helleborus, Aconitum, Thatlictrum,
Paeonia, Pedicularis and Rosa. It seems highly improbable,

96 SUCCESSION

however, that this is an ultimate formation, as Krassnoff
and Warming indicate.

Fliche (1888) investigated the behavior of forest plant-
ations in lower Burgundy, and reached the following con-
clusions, many of which are of general application. The
original plantations, chiefly birch and exotic cultivated
species, were overgrown by the indigenous oaks and beeches,
except on poor ground. Shrubs, bushes and most herbs
disappear as the growth of the trees renders the light more
and more diffuse, In new plantings, the grasses and field
weeds disappear the first year, and are replaced by the
weeds of fallow fields. The latter are overgrown the very
next year by bushes, with which shrubs soon associate
themselves, until finally the invading trees drive out all but
a few shade-loving species. Migration into these areas is
chiefly by birds and winds, the latter bringing by far the
larger number of seeds, though the former are really more
effective because of the greater chance of ecesis. The de-
finitive ecesis of a species is independent of its mobility, as
is seen by the tact that the immobile Fagales completely re-
place the very mobile birches and pines. From his work,
the author derives two general rules of reforestation, which
also hold in large part for similar natural successions,
‘‘Hrstlich ist es fehlerhaft, Moose und Gestripp (Juniperus,
Genista, Prunus,) auf gleiche Stufe zu stellen mit den Acker-
unkraéutern und darum auszurotten: beide verbessern den
Boden, bereiten ihn fiir den Wald vor, fordern die Keimung
der Samen, und schiitzen, wie an mehreren Beispielen
gezeigt wird, die aufschiessenden Baumchen: sind diese
erstarkt, so verschwindet das Gestriipp von selbst; das
Moos aber leistet noch weitere Dienste. Sodann gedeiht
der Wald dann am besten und regeneriert sich auch ohne
Zuthun des Menschen von selbst, wenn er die Arten, und in
dem Verhaltnis enthalt, wie sie in der jeweiligen Gegend
emnheimisch, und eben den beziiglichen Wachstumsbeding-
ungen am besten angepasst sind; und eben dieses Verhilt-
niss stellt sich in einem sich selbst tiberlassenen Walde
immer wieder her.”’

HISTORICAL 97

Douglas (1889) used the term succession in combating the
then prevalent idea, that, when a forest is once destroyed, a
similar forest could never again be established on the same
spot. He pointed out that the period necessary fur such re-
establishment would depend largely upon the mobility of
the trees concerned, but that it was finally to be determined
by the persistence of the species. Warming (1890) found in
the marshy regions along the east coast of the North Sea
that Zostera filtered out and retained the fine particles of soil
in the deeper water, resulting in the formation of mud
banks, while algae and Salicornia herbacea filled the same
office in shallow water. As the ground became higher and
dryer, Glyceria replaced Salicornia, and was accompanied by
Triglochin, Suaeda, Plantago, Glaux, Atriplex, etc.; this vege-
tation was then in its turn driven out by Juncus, Hordeum,
Festuca, Lepturus, Armeria, Artemisia, etc. Kithlmann (1890)
studied the gradual drying up and disappearance of the
Sphagnum swamps, a phenomenon of frequent occurrence in
Russian Lapland. Sphagnum is slowly replaced by the more
xerophytic mosses and by lichens. The earlier fruticulose
forms are followed by a crust of Lecanora tartarica, in which
grow feebly Empetrum, Ledum, and Vaccinium myrtillus. The
succession is then closed, except where the lichen crust is
destroyed by some accidental agency. Kihlmann further
found that young dense growths of birch, in which no con-
iferous seedlings appeared, arose where the forests of red
fir had been burned off, and he concluded that this was due
to the difference in the time necessary for the ripening of
their seeds. The fact that the formation was still young
and dense would seem simply to indicate that the fir had
not yet found the proper conditions for invasion, conditions
which sooner or later must occur.

Kerner (1890 : 267,895), without paying attention to par-
ticular formations, summed up ina graphic though some-
what general way certain main facts of succession.
“This mechanical retention and storage of dust by
rock-plants and of mud by aquatic plants is of the
greatest importance in determining the development of the

89 SUCCESSION

earth’s covering of vegetation. The first settlers on the
bare ground are crustaceous lichens, minute mosses and
algae. On the substratum prepared by them larger lichens,
mosses and algae are able to gain a footing. The dead fila-
ments, stems and leaves pertaining to this second gener-
ation arrest dust in the air and mud in the water, and thus
prepare a soft bed for the germs of a third generation, which
on rocks consists of grasses, composites, pinks and other
small herbs, and in water of pond weeds, water-crowfoots,
hornwort and various plants of the kind. The second gener-
ation is produced in greater abundance than the first, and
the third developes more luxuriantly than the second. The
third may be followed by a fourth, fifth and sixth. Atall
times and in all places, we see younger generations displac-
ing the older and building upon the foundations laid by their
predecessors. The first settlers have a hard fight with un-
compromising elements to seize possession of the lifeless
ground. Years go by before a second generation is enabled
to develop in greater luxuriance upon the earth prepared by
the first occupiers; but there is no cessation in the produc-
tive and regulative effects of vegetable life, and its energy
and aptitude in the work result in the erection of its green
edifices over wider and wider areas. New germs are estab-
lished upon the smouldered dust of dead races, and others
on the plant forms adapted to the altered substratum, and
so, for hundreds and thousands of years, the changes go on,
until at length the tops of forest trees wave above a black
and deep soil, the battlefield of a number of bygone gener-
ations. At least three successive series of settlers may thus
be traced upon every spot, and not infrequently the number
is four or five. Now, if each of these groups corresponds to
a particular community, which isas a matter of fact the
case, the phenomenon described must produce the same im-
pression as though the communities became transformed in-
to one another in the course of time. It is therefore neces-
sary to recognize the existence of the incipient and decadent
stages as well as that of predominance. In the incipient
stage, relics of the community which previously occupied

HISTORICAL 99

the same spot are still to be found, and in the stage of de-
cadence the first pioneers of the community that is to suc-
ceed make their appearance.”’

Korschinsky (1891:473) opposed the view that modifications
of vegetation were entirely dependent upon changed
‘hysico-geographical”’ relations, and brought forward the
development of the oak forests of middle Russia as evidence
in support of this view. He concluded “dass die Hichen-
wilder des mittleren Russlands, welche in Gestalt eines
ununterbrochenen Grenzstriches das Steppengebiet von dem
der Coniferenwialder trennen, auf besagtem Wege entstanden
sind, d. h. dass sie inmitten der freien Wiesensteppen
anfangs in Gestalt strauchartigen Hichengehdlzes hervor-
wuchsen, letzteres sodann mehr und mebr um sich griff und zu
jungen Hichenwaldchen wurde, um sich schliesslich in com-
pacte Waldungen umzubilden, dass also diese Hichenwalder
alle die Stadien durchliefen, wie wir sie jetzt auch noch an
verschiedenen Punkten des Steppengebietes zu beobachten
Gelegenheit haben. Hieraus aber folgt, dass dort, wo wir
jetzt Hichenwalder oder deren Spuren vorfinden, zu einer
fritheren Zeit Steppen existiert haben, die folglich etwas
weiter gegen Norden erstreckten, als wir es jetzt sehen.
Jedoch kénnen die Veriainderungen der Vegetation auch
ganz selbststandig, abgesehen von allen klimatischen Hin-
fliissen erfolgen, indem sie ausschliesslich durch die Lebens-
eigenschaften der concurrierenden Formen, durch das
Erscheinen never Hindringlinge, tiberhaupt durch die
socialen Bedingungen der Pflanzenwelt an
und ftir sich herbeigeftihrt werden.”’ Warming (1891)
traced the building of dunes on the Danish coast and the
development of vegetation upon them. The mobile dunes
begin simply as heaps of sand formed by tides, waves and
wind, the particles of which are as a rule less than one third
of a millimeter in diameter. The further growth of such
dunes is made possible by sandbinders, Psamma arenaria,
Elymus arenarius, Carex arenaria, Agropyrum junceum, Alsine
peploides, etc. The last two are found only on the lower
dunes, and are sooner or later driven out by Psamma and

100 SUCCESSION

Elymus, which are especially adapted to the building of high
dunes, because of their ability to push up through a cover of
sand. Other plants, algae, lichens and mosses, and low-
growing spermatophytes, find their way in among the shoots
of Elymus and Psamma, and, as the sand becomes more and
more fixed, slowly conquer the intervening spaces. The dune
gradually becomes more stable, and is finally spread with a
thick low gray-green cover, before which the two original
sand-binders disappear. Finally, the stable dune may pass
over into a stable Calluna heath. Sernander (1892:9) has
made the following observations in regard to the invasion
of the pine in Scandinavia: “Auf entblésstem Boden
entsteht bekanntlich rasch eine bunte Ansiedlung einer
Menge verschiedenartiger Pflanzenformen. Bald vereinigen
sich diese zu einer geschlossenen Decke und damit ist ein
verhingnisvoller Kampf zwischen den verschiedenen Ansied-
lern eingetreten. Sie ringen mit einander um Licht, Raum
und Nahrung; grosse Massen unterliegen mehr oder weniger
rasch, wahrend eine verhaltnismassig geringe Anzahl sich
tber die Leichen der Besiegten ausbreitet. Aus diesem
riicksichtslosen Kampf geht eine im Verhialtnis zu der mehr
zufallig zusammengekommenen Ansiedlung nach bestim-
mten Gesetzen gebildete Pflanzengesellschaft; d. h. eine
geschlossene Pflanzenformation hervor. Damit hat aber
die Entwicklung nicht aufgehért. Die relative Gleichge-
wichtslage, in welche die die Formation zusammensetzenden
Elemente jetzt gekommen zu sein scheinen, ist selten eine
dauernde. Nicht nur dass gewisse Mitglieder der Gesell-
schaft sich noch immer auf Kosten anderer ausbreiten,
sondern auch neuen Ansiedlern aus der Nachbarschaft
gelingt es, festen Fuss unter den dlteren auf dem Platze zu
fassen, und nun fangt zwischen diesen ein mehr oder
weniger heftiger Streit an. Die Entwicklung der Vege-
tation schlagt neue Wege ein, und gewisse relative Ruhe-
stadien wahrend dieser Entwicklung zeigen sich als dis-
tinkte Formationen, deren gegenseitige Folge einen der
wichtigsten und nachstliegenden Gegenstinde der modernen
biologischen Pflanzengeographie ausmacht. Schliesslich

HISTORICAL 101

muss jedoch ein wirkliches Gleichgewicht eintreten. Man
halt dieses Gleichgewicht fiir erreicht wenn sich die tiber-
lebenden Pflanzenformen in bestimmten Proportionen ver-
jingen und keine neuen Elemente weiter eindringen kénnen.
Die sogenannte Schlussformation ist nunmehr gebildet.’’

Krause (1892, 893) studied the origin of the heaths and
meadows of northern Germany, reaching the conclusion that
the former had for the most part arisen from forests by
reason of cultural changes, while the latter also had resulted
from changes wrought by man in swamp and moor. Fla-
hault and Combres (1894) found Arthrocnemum macrostachyum
to be the pioneer on the low saline alluvium at the mouth of
the Rhone. Afterwards, Salicornia, Atriplex and Aeluropus
established themselves and were in their turn finally dis-
placed by a very different vegetation consisting of Juniperus
and Pinus. Wojeikow (1894) gave a very complete summary
of the way in which man affects vegetation, considering
especially the results of those activities which destroy plant
coverings and consequently initiate succession.

Warming has not only contributed very largely to the
investigation of succession, but he has also made (1895) the
first comprehensive summary of the many scattered results
obtained in this field. He has considered the changes of
vegetation under three heads, which correspond closely to
different types of succession: ‘(1) Neuer Boden (2) Durch
langsamer Verinderungen auf bewachsenem Boden hervor-
gerufene Vegetationsverdnderungen. (3) Vegetationsver-
anderungen ohne Veranderungen im Klima oder im Boden.”’
The following statement constitutes the first attempt to
deduce from various sources the general rules underlying
the principle of succession. ‘‘Hs ist schwierig, schon jetzt
etwas Allgemeines tiber die auf einem neuen Boden auf-
tretende Vegetation zu sagen, weil es dariiber wenige
eingehende Untersuchungen giebt: jedoch scheint folgendes
aus diesen hervorzugehen (vgl. Hult, Grevillius, u. a.).

1. Die erste Vegetation ist offen. Es vergeht immer einige
Zeit, bevor sich eine zusammenhingende Vegetationsdecke

102 SUCCESSION

bildet. Die Individuen stehen anfangs sehr zerstreut, aber
allmahlich wird ihre Menge grosser.
2. Die Artenzahl ist anfangs gering, wichst jedoch und ist
nach Verlauf einer gewissen Zeit grosser als spater, indem
viele Arten anfanglich einen giinstigen Platz finden, aber
spiter verdringt werden, wenn sich die Decke schliesst und
sich tyrannischere Arten eingefunden haben. Verschiedene
Teile des neubewachsenen Geldndes werden sich oft sehr
ungleichartig mit Pflanzen bedecken. Allmahlich wird die
Vegetation gleichartige und artenarmer,
8. Sehr oft werden ein-und zweijahrige Arten zuerst viel
zahlreicher als spater sein, indem sie auf dem offenen
Gelainde giinstigere Bedingungen finden als auf dem bedeck-
ten: viele werden der Unkrautflora der Gegend angehoren.
Darauf werden die mehrjahrigen Krauter oder die Holz-
pfianzen iiberwiegen.
4. Die zuerst einwandernden Arten werden die sein, welche
in der Nahe vorkommen und die besten Mittel fiir die
Verbreitung durch Wind oder Végel haben. Die Gerdll-
halden der Alpen werden zuerst von Arten mit fliegenden
Samen besiedelt (Kerner). Wird in Norwegen ein Nadel-
wald zerstért, so wandern zuerst Birken und VPappel
(leichter fliegende Friichte und Samen) nebst Sorbus (Beeren)
ein (Blytt, Hult).
5. Handelt es sich um die Hinwanderung von Baumen, so
werden die Lichtbaume oft vor den Schatten ertragenden
erscheinen; das Umgekehrte kann nicht stattfinden.
6. Die Ausbildung zu ausgeprigten Vereinen geht allmih-
lich vor sich. Die ersten, miteinander gemischten Individuen
gehdren in Wirklichkeit zu verschiedenen natiirlichen Ver-
einen, die sich erst nach und nach auf die passendsten
Standorte vertheilen. Man kann demnach von Anfangs-.
Ubergangs-, und Schlussvereinen sprechen’’.
Graebner (1895:500) has made a careful study of the origin
of the heath formation in northern Germany. In the devel-
opment of the heath upon the litoral dunes, the strand
plants are replaced to some degree by annual sandbinders,
Jasione, Eriophila, and Spergula, between which appear Aira,

HISTORICAL 1038

Arabis, Solidago and Chrysanthemum. In the protection of the
individuals of these species develop colonies of lichens,
Cladonia, Cetraria islandica, Baeomyces roseus, etc. and mosses,
Bryum argenteum, Dicranum scoparium, Ceratodon purpureus,
etc., while here and there spring up little plantlets of
Calluna and Empetrum. During rainy seasons, a tenacious
crust of algae, largely Cyanophyceae, covers the sand every-
where; this crust serves to hold the sand particles together,
and upon dying produces the first humus. The mosses also
play an important part in fixing the sand, in as much as
many species, when more or less covered by the blowing
sand particles, send up new shoots, forming a tuft. The
lichens especially are humus builders. Finally, in a locality
modified in the way above, the seedlings of flowering plants
are able to maintain themselves in large quantity. Calluna
and Hmpetrum enter more and more abundantly, Jasione,
Leucanthemumn and Solidago decrease in number, while
Hypnum schrebert spreads steadily and covers the moist
places with a thick turf. In a similarly detailed fashion,
Graebner has traced the development of the heath moor and,
more generally, the modification of forest, and heath moor
into heath, as well as the changes exhibited by the latter,
especially under culture. Greviflius (1895) investigated the
vegetation of the islets of the Hjelmar sea, which Callmé had
studied in 1886. He found 215 species in place of the 115
observed by the latter. These were more uniformly dis-
tributed over the island, and the vegetation had become
much more closed. The typical structure of the vegetation
was as follows: (1) a strand-zone of grasses and sedges, (2)
a zone of shrubs, mostly Saliz, below which grew small
strand plants, (3) a central nucleus of dense young forest,
mostly of Letula verrucosa, Populus tremula, and Alnus gluti-
nosa. Pines were found sparingly on a few of the islands.
Meigen (1896:212) found that, in the vineyards of Saxony,
which had been destroyed to exterminate the Phylloxera,
78% of the invaders of the first year were annual, 13%
biennial, ruderal plants, 18% were perennials, while none
were woody plants. The changes of the second year con-

104 SUCCESSION

sisted in the disappearance of some of these, but especially
in the entrance of new invaders. Of the former, the annuals
were the first to disappear, while of the latter, perennials
were in the majority. After six years, vegetation was still
largely ruderal. From his work, Meigen has deduced the
following conclusions: ‘‘Bei gleichen oder wenig verschie-
denen climatischen Verhaltnissen hangt die Folge der For-
mationen in erster Linie von der Bodenbeschaffenheit ab.
Zunichst kommt es also darauf an, festzustellen, was fir
verschiedene Standorte innerhalb des zu untersuchenden
Gebietes vorkommen, wobei sich eine Gliederung der Stand-
orte ergeben muss aus der physikalischen und chemischen
Beschaffenheit, sowie aus ihren Beziehungen zu Warme,
Licht und Feuchtigkeit, also den Faktoren, die vor allen den
Charakter der Vegetation bestimmen. Dann ist auszugehen
von einem véllig von Pflanzen und Vegetation freien Boden
und nun zu ermitteln, welche Formationen sich hier auf den
verschiedenen Standorten ansiedeln. Auf festem Fels, auf
losem Sand, in stehendem Wasser, in Bachen und Fliissen,
iiberall finden wir besondere Gemeinschaften, die in ihren
Gliedern und ihrer Gesamtheit fiir den besonderen Standort
auch besonders organisiert sind. Jede dieser Hinzelforma-
tionen muss dann fir sich weiter verfolgt werden, es sind
die Anderungen zu untersuchen, die sie erleidet und die
schliesslich zur Herstellung einer Folgeformation fihren.
Daraus ergeben sich dann Reiben von Formationen, die
unter sich aufs engste zusammenhingen, weil jede folgende
sich aus der vorhergehenden entwickelt hat. So wird man
endlich zu einer Formation gelangen, die nun, sich selbst
tiberlassen, keine Anderung mehr unterliegt, also die
Schlussformation der Reihe bildet, womit das Gleichge-
wicht an dem betreffenden Standort hergestellt ist. Nun
sind die gegenseitigen Beziehungen dieser Formationsreihen
zu bestimmen. Daraus wird sich dann ergeben, ob die
Schlussformation einer Reihe durch Bertthrung mit Forma-
tionen aus andern Reihen noch weitere Verinderungen
erleiden kann. Es kann auch eine Formation Schluss-
formation mehrerer Reihen sein, so dass diese convergieren,

HISTORICAL 105

wihrend andere parallel neben einander laufen. Auch
schon vor Ausbildung einer Schlussformation trifft nicht
selten eine Reihe mit einer anderen zusammen und geht in
deren Richtung weiter.’

Pound & Clements (1898: 216, 259) traced the development
of the blowout formation and of waste formations on denuded
areas. They distinguished formations as primitive or
recent with respect to origin; the latter alone are to be con-
sidered in the study of existing successions. Recent
formations arise by nascence, asin the case of areas desti-
tute of a floral covering, or by modification, when a patch or
formation is changed by the invasion of other species.
Cowles’ work (1899:95) on the dune vegetation of Lake
Michigan, modelled after Warming’s studies on the Den-
mark coast, was the first special account of succession to be
published in this country. The author has classified dunes
as embryonic, wandering and established, and has followed
the detailed development of vegetation in each of these.
His conclusions form an excellent résumé of the stages in
dune successions. Wifsson ($899: 89) followed in a detailed
manner the development of vegetation on the cliffs and in
the swamps of middle Sweden. The cliff succession is
especially interesting on account of the full treatment of the
lichen stages. Cowles (1901:73) has applied his methods of
successional research to the study of river-valleys and shore-
lines with very instructive results, and he has summed up
his investigations in a developmental classification of much
value. Whitford (1901:289) has made a study of the forests of
northern Michigan along the same lines. Weber (1901 , 1902)
has made further contributions to the developmental history
of moor and forest, Graebner (1902) to the phylogeny of the
heath vegetation and Clements (1902) to the succession of
talus formations.

Succession is the phenomenon in which a series of in-
vasions occurs in the same spot. It is important, however,
to distinguish clearly between succession and invasion, for,
while the one is the direct result of the other, not all in-
vasion produces succession. The number of invaders must

106 SUCCESSION

be large enough, or their effect must be sufficiently modify-
ing or controlling to bring about the gradual decrease or
disappearance of the original occupants, or a succession will
not be established. Partial or temporary invasion can
never initiate «a succession unless the reaction of the in-
vaders upon the habitat is very great. Complete and per-
manent invasion, on the other hand, regularly produces suc-
cessions, except in the rare cases where a stable formation
entirely replaces a less stable one without the intervention
of other stages Succession depends in the first degree up-
on invasion in such quantity and of such character that the
reaction of the invaders upon the habitat will prepare the
way for further invasion. The characteristic presence of
stages in a succession, which normally correspond to form-
ations, is due to the peculiar operation of invasion with re-
action. In the case of adenuded habitat, for example, mi-
gration from adjacent formations is constantly taking place,
but only a small number of migrants especially adapted to
somewhat extreme conditions are able to become established
in it. These reach a maximum development in size or
number, and, in so doing, react upon the habitat in sucha
way that more and more of the dormant disseminules pre-
sent, as well as those constantly coming into it, find the con-
ditions favorable for germination and growth. The latter,
as they in turn attain their maximum, cause the gradual dis-
appearance of the species of the first stage, and at the same
time prepare the way for the individuals of the succeeding
formation. It is at present impossible to determine to what
degree this substitution is due to the struggle for existence
between the individuals of each species and between the
somewhat similar species of each stage, and to what degree
it arises out of the physical reaction.

It is evident that geological succession is but a larger ex-
pression of the same phenomenon, dealing with infinitely
greater periods of time, and produced by physical changes
of such intensity as to give each geological stage its peculiar
stamp. If, however, the geological record were sufficiently
complete, we should find unquestionably that these great

PRIMARY SUCCESSIONS 107

successions merely represent the stable termini of many
series of smaller changes, such as are found everywhere in
recent or existing vegetation.

The fundamental causes of succession are invasion and
reaction, but the initial causes of a particular succession are
to be sought in the physical or biological disturbances of a
habitat or formation. With reference to the initial cause,
we may distinguish normal succession (successio nor-
malis), which begins with nudation, and ends in stabilis-
ation, and anomalous succession (successio anomala),
in which the facies of an ultimate stage of a normal suc-
cession are replaced by other species, or in which the direc-
tion of movement “is radically changed. The former is of
universal occurrence and recurrence; the latter operates up-
on relatively few ultimate formations. In the origin of
normal successions, nudation may be brought about by the
production of new soils or habitats, or by the destruction of
the formation which already occupies a habitat. Ina few
cases, the wav in which the habitat arises or becomes
denuded is not decisive as to the vegetation that is developed
upon it, but as a rule the cause of nudation plays as import-
ant a part in the development of a succession as does the
reaction exerted by the invaders. The importance of this
fact has been insisted upon under invasion. New soils pre-
sent extreme vonditions for ecesis, possess few or no dormant
disseminules, and, in consequence, their successions take
place slowly and exhibit many stages. Denuded soils asa
rule offer optimum conditions for ecesis, as a result of the
action of the previous succession, dormant seeds and pro-
pagules are abundant. and the revegetation of such habitats
takes place rapidly and shows few stages. The former may
be termed primary succession (successio primitiva),
the latter, secondary succession (successio secuta).

PRIMARY SUCCESSIONS

These arise on newly formed soils, or upon surfaces ex-
posed for the first time, which have in consequence never
borne vegetation before. In general they are character-
istic of mountain regions, where weathering is the rule,

108 SUCCESSION

and of lowlands and shores, where sedimentation or ele-
vation constantly occur. The principal physical phenomena
which bring about the formation of new soils are: (1) ele-
vation , (2) volcanic action, (3) weathering, with or with-
out transport.

1. Succession through elevation. EHlevation was
of very frequent occurrence during the earlier, more plastic
conditions of the earth, and the successions arising as a
result of it must have been important features of the vege-
tation of geological periods. Today, elevation is of much
less importance in changing physiography, and its operation
is confined to volcanic islands, coral reefs and islets, and to
rare movements or displacements in sea coasts, lake beds,
shore lines, etc. There has been no investigation of the de-
velopment of vegetation on islands that are rising, or have
recently been elevated, probably because of the slow growth
of coral reefs and the rare appearance of volcanic islands.
On coral reefs, the first vegetation is invariably marine, but
as the reef rises higher above the surf line and the tide, the
vegetation passes into a xerophytic terrestrial type adapted
to an impervious rock soil, and ultimately becomes meso-
phytic. In volcanic islands, unless they are mere rocks
over which the waves rush, the succession must always be-
gin with a xerophytic rock formation. The best known ex-
ample of a rising coast line is found in Norway and Sweden,
where the southeastern coast is rising at the rate of five or
six feet acentury. There can be little question that such
changes of level will produce marked changes in vegetation,
but the modification will be so gradual as to be scarcely
perceptible in a single generation. It is probable that the
forests of the Atlantic coastal plains are the ultimate stages
of successions initiated at the time of the final elevation of
the sea bottom along the coast line.

2. Succession through volcanic action. The
deposition of vulcanic ashes, and flows of lava are relatively
infrequent at present, occurring only in the immediate
vicinity of active volcanoes, chiefly in or near the tropics.
Successions of this sort are in consequence not only rare,

PRIMARY SUCCESSIONS 109

but they are also relatively inaccessible to investigaturs.
They have been studied in a few cases, for example, those
of Krakatoa by Treub, but this study has been confined to
the general features of revegetation. Ash fields and lava
‘beds are widely different in compactness, but they agree in
having a low water and nutrition content. The pioneer
plants in both will be intense xerophytes, but the soil
differences will determine that these shall be sandbinders
in the former, and rock-weathering plants in the latter.
Practically all primary successions start on soils produced
by weathering: this is also true of coral or volcanic islets
and of lava beds, for no terrestrial vegetation can secure a
foothold upon them until the surface of the rock has been
to some extent decomposed or disintegrated. Weathering,
as is well known, consists of two processes, disintegration
and decomposition, which usually operate successively,
though they are sometimes concomitant. Disintegration
usually precedes, especially in rock masses, and, unless it
is soon followed by decomposition, results in dysgeogenous
soils. Decomposition often goes hand in hand with disinte-
gration, or it takes place so ravidly and perfectly that it
alone seems to be present. In either case, the resulting
soil is eugeogenous. The relation of decomposition to dis-
integration determines the size and compactness of the soil
particles, and upon the latter depend the porosity, capillarity
and hygroscopicity of the soil. These control in large degree
the character of the first vegetation to appear on the soil.
Another point of fundamental value in determining re-
vegetation is the disposition of the weathered rock. If it
remains in situ, it will evidently differ in respect to compact-
ness, homogeneity, nutrition content, water content, dissem-
inules, etc., from weathered material which has been trans-
ported. Anessential difference also arises from the fact that
arock may be weathered a long distance from the place
where the decomposed particles are finally deposited, and
in the midst of a vegetation very different from that found
in the region of deposit. The disposition of the weathered
material affords in consequence a satisfactory basis for the

110 SUCCESSION

arrangement of primary successions. The following classifi-
cation is proposed, based upon the soil groups established
by Merrill (£897 : 300).

3. Successionin residuary soils. Residuary
soils are always sedentary, i. e., they are formed in situ.
They show certain differences dependent upon the rock from
which they originate, which may be mixed crystalline shale,
sandstone or limestone, but the thoroughness of decomposi-
tion causes these differences to be comparatively small.
Residuary soils are typically eugeogenous: their successions
in consequence usually begin with mesophytes, and consist
of a few stages. The soluble salt content is comparatively
low, since all soluble matters are readily leached out. Suc-
cessions in these soils are especially characteristic of shale,
sandstone and limestone ledges or banks. Cumulose depos-
its, like residuary ones, are sedentary in character, but, as
they are produced by the accumulation of organic matter,
they will be considered under reactions of vegetation upon
habitat.

4. Succession in colluvial soils. Colluvial de-
posits owe their aggregation solely or chiefly to the action
of gravity. They are the immediate result of the disinte-
gration of cliffs, ledges and mountain sides, decomposition
appearing later as a secondary factor. The masses and
particles arising from disintegration are extremely variable
in size, but they agree as a rule in their angular shape. The
typical example of the colluvial deposit is the talus, which
may origiaate from any kind of rock, and contains pieces of
all sizes. Gravel slides differ from ordinary talus in being
composed of more uniform particles, which are worn round
by slipping down the slope in response to gravity and sur-
face wash. Boulder fields are to be regarded as talus pro-
duced by weathering under the infiuence of joints,resulting
in huge boulders which become more and more rounded under
the action of water and gravity. This statement applies to
those fields which are in connection with some cliff that is
weathering in this fashion: otherwise, boulder fields are of
aqueous or glacial origin. The character of the successions

PRIMARY SUCCESSIONS 111

in talus will depend upon the kind of rock in the latter. If
the rock is igneous or metamorphic , decomposition will be
slow, and the soil will be dysgeogenous. Successions on
such talus consist of many stages, and the formations are
for a long time open and xerophytic. In talus formed from
sedimentary rocks, especially shales, limestones, and calcar-
eous sandstones, decomposition is much more rapid, and the
successions are simpler and more mesophytic.

5. Succession in alluvial soils. Alluvial soils
are fluvial when laid down by streams and rivers, and litoral
when washed up by the waves or tides. They are formed
when any obstacle retards the movement of the water, de-
creasing its carrying power, and causing the deposit of part
or allof its load. They consist of more or less rounded,
finely comminuted particles, mingled with organic matter
and detritus. Alluvial deposits are especially frequent at the
mouth of streams and rivers, on their terraces and flood
plains, and along silting banks as compared with the erosion
banks of meanders. The filling of ponds by the erosion due
to surface drainage, and of lakes by the deposition of the
loads of streams that enter them, results in the formation of
new alluvium. A similar phenomenon occurs along coasts,
where bays and inlets are slowly converted into marshes in
consequence of being shallowed by the material washed in
by the waves and tides. Such paludal deposits are invari-
ably salt water or brackish. Contrasted with these, which
are uniformly black in consequence of the large amount of
organic matter present, are the sandbars and _ beaches,
which, though due to the same agents, are light grey or
white in color, because of the constant leaching by the
waves. Two kinds of alluvial deposits may accordingly be
distinguished: (1) those black with organic matter, and
little disturbed by water, and (2) those of a light color,
which are constantly swept by the waves. The successions
corresponding to these are radically different. In the first,
the pioneer vegetation is hydrophytic. consisting largely of
amphibious plants. The pioneer stages retard the move-
ment of the water more aud more, and correspondingly

112 SUCCESSION

hasten the deposition of its load. The marsh bed slowly
rises in consequence, and finally the marsh begins to dry
out, passing first into a wet meadow, and then into a meadow
of the normal type. A ‘notable exception to this sequence
occurs when the swamp contains organic matter or salts in
excess, in which case the vegetation consists indefinitely of
swamp xerophytes, or halophytes. The first vegetation on
freshwater sandbars is xerophytic, or, properly, dissophytic,
unless they remain water-swept, and the ultimate stages of
their successions are mesophytic woodlands composed of
water-loving genera, Populus, Salix, etc. It seems certain,
however, that these will finally give way to longer-lived
hardwoods. Maritime sandbars and beaches are always
saline, and their successions run their short course of
development entirely within the group of halophytes, unless
the retreat of the sea, or freshwater floods change the char-
acter of the soil. The chemical action of underground
waters also produces new soils, which might be classed as
alluvial. These soils are essentially rock deposits, traver-
tine, silicious sinter, etc., made by iron and hme springs,
and by geysers, and they must be changed by decomposition
into soils proper to be comparable with alluvial soils.

6. Succession in aeolian soils. The only wind-
borne soils of geological importance at the present time are
those which form dunes, both inland and coastal. Aeolian
deposits consist largely of rounded sand particles, which
are of almost uniform size in any particular dune, but vary
greatly in dunes of different ages. The reaction of the
pioneers on dunes plays an important part in building the
latter, but the immense dunes of inland deserts, which are
entirely destitute of vegetation, seem to indicate that its
value has been overestimated. The first stagesin dune suc-
cessions are dissophytic, i. e., the plants grow in a soil of
medium or high water content, but in an atmosphere that is
extremely xerophytic. The ultimate stages vary widely in
accordance with the region in which they occur: they may be
xerophytic heaths, or mesopbytic meadows and forests. Be-
cause of their striking character and economic significance,

SECONDARY SUCCESSIONS 118

dunes have received much attention, with the result that
their successions are the most thoroughly known of all.
Prairie and steppe formations are probably to be regarded
as the ultimate stages of successions established on wind-
borne loess, and it is possible that the same is true of sand-
hill vegetation in the prairie province.

7%. Succession in glacial soils. The formation of
glacial deposits is at present confined to alpine and arctic
regions. Recent successions in such soils are localised in
these regions, and are in consequence relatively unimport-
ant. There can be little question, however, that the thor-
ough investigation of succession in and near the moraines of
existing glaciers will throw much light upon the successions
of the glacial period. Moraines, drumlins, eskars and allu-
vial cones represent the various kinds of glacial deposits.
They agree in being heterogeneous in composition, and are
covered today with ultimate stages of vegetation, except in
the immediate vicinity of glaciers.

SECONDARY SUCCESSIONS

Generally speaking, all successions on denuded soils are
secondary. When vegetation is completely removed by
excessive erosion, it is an open question whether the result-
ing habitat is to be regarded as newor denuded. Erosion
is rarely so extreme and so rapid, however, as to produce
such a condition, even when it results from cultivation or
deforestation. It is, moreover, especially characteristic of
newly formed soils, and, in studying succession in eroded
habitats, it is fundamentally important to determine
whether erosion has produced denudation, or has operated
upon a new soil. The great majority of secondary success-
ions owe their origin to floods, animals, or the activities of
man, and they agree in occurring upon decomposed soils of
medium water content, which contain considerable organic
matter. and a large number of dormant migrants. These
successions consist of relatively few stages, and are rarely
of extreme character.
8. Succession in erodedsoils. Eroded soils show
considerable differences, as they arise in consequence of

114 SUCCESSION

erosion by water, or by wind, though the initial stages of
revegetation derive their character more from the aggrega-
tion of the soil than from the nature of the erosive agent.
Eroded soils are as a rule xerophytic. In the case of eros-
ion by water, dysgeogenous soils are readily worn away in
consequence of their lack of cohesion, as in sanddraws, etc.,
while eugeogenous soils are easily eroded only on slopes,
as in the case of ravines, hillsides, etc. In the former,
the extreme porosity and slight capillarity of the sand and
gravel result in alow water content: in the finer soils, the
water content is also low, on account of the excessive run-
off, due to compactness of the particles and to the slope.
The erosive action of winds upon soils bearing vegetation
is not very general: it is found to some extent in more or less
established dunes, and exists in a marked degree in buttes,
mushroom rocks and blowouts. The first two are regularly
xerophytic, the last as a rule, dissophytic. The early
stages of successions in eroded soils are composed of
xerophytes. In loose soils, these are forms capable of
binding the soil particles together, thus preventing wash, and
increasing the accumulation of fine particles, especially of
organic matter. In compact soils, the effect is much the
same: the pioneers not only decrease erosion, but at the
same time also increase the water content by retarding the
movement of the run-off.

9. Succession in flooded soils. The universal
response of vegetation to floods is found in the amphibious
plant, which is aplastic form capable of adjustment to very
different water contents. Floods are confined largely to
river basins and coasts: in hilly and mountainous regions,
where the slope is great, any considerable accumulation of
flood waters is now impossible, although of freauent oc-
currence when land forms were more plastic.

In all streams that have become graded, the fall is in-
sufficient to carry off the surplus water in the spring when
snows are melting rapidly, or at times of unusual precipit-
ation. These waters (accumulate, and, overflowing the
banks, spread out over the lowlands, resulting in the form-

SECONDARY SUCCESSIONS 115

ation of a well-defined flood plain. This is a periodical
occurrence with mature streams, and it occurs more or less
regularly with ail that are not torrent-like in character.
The effect of the overflow is to destroy or to place ata dis-
advantage those plants of the flood plain that are not hydro-
phytes. At the same time, a thin layer of fresh silt is
deposited upon the valley floor of sand or alluvium. Flood-
ing is most frequent and of longest duration near the banks
of the stream. It extends more or less uniformly over the
flood plain, and disappears gradually or abruptly as the
latter rises into the bench above. Floods destroy vegetation
and make a place for secondary successions by drowning out
mesephytic species, by washing away the aquatic forms of
ponds and pools, and by the erosion of banks and sandbars.
They affect the amphibious vegetation of swamp and shore
vo a certain extent, but, unless the period of flooding is long,
they tend to emphasize such formations rather than to de-
stroy them. The stillwater formations of many cutoff and
oxbow lakes owe their origion to a river which cuts across
a meander in time of flood. This result is more often
attained by the alternate silting and erosion of a meander-
ing river by which it cuts across a bend in its channel. The
usual successions in flooded lands are short as a rule: am-
phibious algae, liverworts and mosses soon give way to
ruderal plants, and these in turn to the original mesophytes
of meadows, or dissophytes of sandbars. In the case of
ponds and pools, the process of washing-out or silting-up
merely removes or destroys the vegetation, without
effectively modifying the habitat, and the secondary suc-
cessions that follow are extremely short.

10. Succession by subsidence. Subsidence is a
factor of the most profound importance in changing vege-
tation. It operates over vast areas through immense
periods of time. For these reasons, the changes are so slow
as to be almost imperceptible, and the resulting successions
can be studied only in the geological record. Extensive
subsidence is confined today to coastal plains, as in Green-
land, the south Atlantic coast, and the region of the Missis-

116 SUCCESSION

sippi delta, where its effects are merged with the paludation
of tidal rivers, and the wave and tide erosion of the sea
shore. Such successions are unique in as much as the
denuding force operates very slowly instead of quickly, and
the first pioneers of the new vegetation appear before the
original formation has been destroyed. In all cases, the
succession is from mesophytic or halophytic formations to
paludose, and, finally, marine vegetation. In small areas of
subsidence, such as shore slips along lakes and streams,
sink holes and sunken bogs, the succession is usually both
short and simple, mesophytes giving place to amphibious
and ultimately to aquatic forms.

11. Succession in landslips. lLandslips occur
only in montane and hilly regions, and here they are
merely of local importance. In many respects, they are not
unlike talus: they show essential differences, however, in
that they are not sorted by gravity, and in that they destroy
vegetation almost instantly. The succession arises as a
rale, not upon the original soil, but upon that of the land-
slip, and, as pointed out elsewhere, might well be regarded
as primary.

12. Succession in drained, or dried soils.
In geological times, the subsidence of barriers must often
have produced drainage and drying-out, just as elevation
frequently resulted in flooding and lake formation. At the
present time, the drying-out of lakes and ponds is the result
of artificial drainage, or of climatic changes. The former
will be considered under successions brought about by the
agency of man. Climatic changes when general operate so
slowly that the stages of such successions are perceptible
only when recorded in strata. More locally, climate swings
back and forth through a period of years, with the result
that in dry years the swamps and ponds of wetter seasons
are dried out, and the vegetation destroyed or changed. If
the process be gradual, the succession passes from hydro-
phytic through amphibious to mesophytic, and, in dry
regions, xerophytic conditions: when the process of drying
out occurs rapidly, as in a single summer, the original for-

SECONDARY SUCCESSIONS 117

mation is destroyed, and the new vegetation consists largely
of ruderal plants. A peculiar effect of climate occurs in
regions with poor drainage, where the result of intense
evaporation is to produce alkaline basins and salt lakes, in
which the succession becomes more and more open, and is
finally represented by a few stabilized halophytes, or dis-
appears completely.

13. Succession by animal agency. Succes-
sions of this class are altogether of secondary importance,
the instances in which animals produce denudation being
relatively few. Such are the heaps of dirt thrown up by
prairie dogs, and uther burrowing animals, upon which
ruderal plants are first established, to be finally crowded out
by the species of the original formation. Buffalo wallows
farnish examples of similar successions in which the initial
stages are subruderal, while overstocking and overgrazing
frequently produce the same result with ruderal plants.

14. Succession by human agency. The activ-
ities of man in changing the surface of the earth are so
diverse that it is impossible to fit the resulting successions
in a natural system. While man does not exactly make new
soils, he exposes soils in various operations, mining, irri-
gation, railroad building, etc. He destroys vegetation by
fires, lumbering, cultivation and drainage, and, if he cannot
control climate, he at least modifies its natural effects by
irrigation and the conservation of moisture. The oper-
ations of man extend from sea coasts and swampy lowlands
through mesophytic forests and prairies to the driest up-
lands andinlands. Since the adjacent formations determine
in large degree the course and constitution of a succession,
it will be seen that the effects of any particular activity up-
on vegetation will differ greatly in different regions. For
convenience, all classes of successions arising from the
presence and activity of man will be considered in this
place, though, as indicated above, some might well be
regarded as producing primary successions, while others
Produce anomalous ones.

118 SUCCESSION

(a) Succession in burned areas. It will suffice
merely to point out that ‘“‘burns’’ may arise naturally
through lightning, volcanic cinders, lava flows, etc., but the
chances are so slight that these causes may be ignored.
The causes of fires are legion, and, as they have little or no
effect upon results, they need not be considered. From
their nature, fires are of little significance in open veget-
ation, deserts, polar barrens, alpine fields etc., since the
area of the burn can never be large. In closed formations,
the extent of fires is limited only by the area of the veget-
ation, and the effect of wind, rain and other forces. Forest
fires usually occur during the resting period, except in the
case of coniferous forests. In grassland, the living parts
are underground during autumnu and winter, when prairie
fires commonly occur. As a consequence, the repeated
annual burning of meadow or prairie does not result in
denudation and subsequent succession. On the contrary, it
acts in part as a stabilising agent, in as much as it injures
the typical vegetation forms of grassland much less than it
does the woody invaders. All formations with perennial
parts above ground,, viz. thicket, open woodland, and forest,
are seriously injured by fire. A severe general fire de-
stroys the vegetation completely: a local fire destroys the
formation in restricted areas, while a slight or superficial
burn removes the undergrowth and hastens the disappear-
ance of the weaker trees. In the latter case, while the pri-
mary layer of the forest remains the same, succession takes
place in the herbaceous and shrubby layers. These succes-
sions are peculiar in that they are composed almost wholly
of the proper species of the forest, and that they are very
short, showing only a few poorly defined stages. A local
fire initiates a succession in which the pioneers are derived
largely from the original formation, particularly when the
latter encloses the burned area more or less completely.
The constitution of the intermediate and ultimate stages
will depend in a larger degree still upon the size and
position of the burn. When a particular formation is de-
stroyed wholly or in large part, the first stages of the new

SECONDARY SUCCESSIONS 119

vegetation are made up by invaders from the adjacent form-
ations. In the most perfect types of succession, this dis-
similarity between the new and the old vegetation continues
to the last stage, in which the reappearance of the facies
precedes that of the subordinate layers. In many forest
successions, however, the general physical similarity of the
ultimate stages permits the early reappearance of the her-
baceous and shrubby species, and the final stages affect the
facies alone. Successions in burned areas operate usually
within the water content groups. The reconstruction of a
mesophytic forest takes place by means of mesophytes; of
the rarer xerophytic and hydrophytic forests, through
xerophytes and hydrophytes respectively. Thisis due to
the fact that the alteration of the soil is slight, except
where the burning of the vegetation permits the entrance of
erosion, aS on mountain slopes.

(b) Succession in lumbered areas. Com-
mercial lumbering, especially where practised for wood-
pulp as well as for timber, results in complete or nearly
complete destruction of the vegetation by removal and the
change from diffuse light to sunlight, or by the action of
erosion upon the exposed surface. In the first place, short
mesophytic successions will result: in the second, the suc-
cessions will be long and complex, passing through de-
creasingly xerophytic conditions to a stable mesophytic
forest. Where a forest is cut over for certain species alone,
the undisturbed trees soon take full possession, though the
causes effective in the beginning will ultimately restore the
original facies in many instances. Such successions are
anomalous, and will be treated under that head.

(c) Suecession by cultivation. The clearing
of forests and the ‘“‘breaking’’ of grassland for cultivation
destroy the original vegetation: the temporary or permanent
abandonment of cultivated fields then permits the entrance
of ruderal species, which are the pioneers of new suc-
cessions. This phenomenon takes place annually in fields
after harvest, resulting in the secondary formations of
Warming, in which practically the same species reappear

120 SUCCESSION

year after year. In fields that lie fallow for several years,
or are permanently abandoned, the first ruderal plants are
displaced by new-comers, or certain of them become domin-
ant at the expense of others. In a few years, these are
crowded out by invaders from the adjacent formations, and
the field is ultimately reclaimed by the original vegetation,
unless this has entirely disappeared from the region. The
number of stages depends chiefly upon whether the final
formation is to be grassland or woodland. Other activities
of man, such as the construction of buildings, roads, rail-
ways, canals, etc., remove the native vegetation, and make
room for the rapid development of ruderal formations. In
and about. cities, where the original formations have en-
tirely disappeared, the chance for succession is remote, and
the initial ruderal stages become more or less stabilised.
Elsewhere the usual successions are established, and the
ruderal formation finally gives way to the dominant type.
In mountain and desert regions, where ruderal plants are
rare or lacking, their place is taken by subruderal forms,
species of the native vegetation capable of rapid movement
in them. These, like ruderal plants, are gradually replaced
by other native species of less mobility, but of greater per-
sistence, resulting in a short succession operating often
within a single formation. From the nature of cultivated
plants, succession after cultivation generally operates with-
in the mesophytic series.

(a4) Succession by drainage. Successions of
this kind show much the same stages as are found in those
due to flooding. They proceed from aquatic or swamp for-
mations to mesophytic termini, either grassland or wood-
land. When drainage takes place rapidly and completely,
the pioneer stages are usually xerophytic: cases of this sort,
however, are infrequent.

(e) Succession by irrigation. Irrigation pro-
duces short successions of peculiar stamp along the courses
of irrigating canals and ditches, and in the vicinity of
reservoirs. These are recent, as a rule, and are usually
found in the midst of cultivated lands, so that their complete

ANOMALOUS SUCCESSIONS 121

history is still a matter of conjecture. The original xero-
phytes are forced out not only by the disturbance of the
soil, but also by its increased water content. A few of them
often thrive under the new conditions, and, together with
the usual ruderal plants and a large number of lowland
mesophytes and zmphibious forms derived from the bunks
of the parent stream, constitute a heterogeneous association.
This is doubtless to be regarded as an initial stage of a suc-
cession, but it is an open question whether the succession
will early be stabilised as a new formation, or whether the
original vegetation will sooner or later be reestablished
under somewhat mesophytic conditions. From the number
of mesophytes and from the behaviorof valleys, it seems
certain that the banks of such canals will ultimately be
occupied by a formation more mesophytic than hydrophytic,
into which some of the surrounding xerophytes of plastic
nature have been adopted.

Anomalous successions are those in which the physical
change in the habitat is relatively slight, resulting in a dis-
placement of the ultimate stage, or the disturbance of the
usual sequence, merely, instead of the destruction and re-
construction of a formation, or the gradual development of
a new series of stages on new soil. In nature, the ultimate
grass or forest stage of a normal succession is often re-
placed by a similar formation, especially if the facies be few
or single. It is evident that certain trees naturally replace
others in the last stages of a forest succession, without
making the latter anomalous. The last occurs only when a
normal stage is replaced by one belonging properly to an
entirely different succession, as when a coniferous forest re-
places a deciduous one in a hardwood region. The presence
and development of such successions can be determined only
atter the normal types are known. The interpolation of a
foreign stage in a natural succession, or a change of direc-
tion, by which a succession that is mesotropic again becomes
hydropbytic, is easily explained when it is the result of
artificial agents, as is often the case. In nature, anomalous

122 SUCCESSION

successions are commonly the result of a slow backward and
forward swing of climatic conditions.

A normal succession will regularly be perfect (successio
perfecta) ; it passes in the usual sequence from initial to ulti-
mate conditions, without interruption or omission. Imper-
fect succession (successio imperfecta) results when one or more
of the ordinary stages is omitted anywhere in the course,
and a later stage appears before its turn. It will occur at
any time when a new or denuded habitat becomes so sur-
rounded by other vegetation that the formations which
usually furnish the next invaders are unable to do so, or
when the abundance and mobility of certain species enable
them to take possession before their proper turn, and to the
exclusion of the regular stage. Incomplete successions are
of great significance, in as much as they indicate that the
stages of a succession are often due more to biological than
to physical causes, the proximity and mobility of the
adjacent species being more determinative than the physical
factors. Subalpine gravel slides regularly pass through
the rosette, mat, turf, thicket, woodland and forest stages:
occasiunally, however, they pass immediately from the
rosette, or mat condition to an aspen thicket which repre-
sents the next to the last stage. Such successions are by
no means infrequent in hilly and montane regions: in
regions physiographically more mature or stable, perfect
successions are almost invariably the rule.

It may be stated asa general principle that vegetation
moves constantly and gradually toward stabilisation.
Each successive stage modifies the physical factors, and
dominates the habitat more and more, in such a way that
the latter seems to respond to the formation rather than
this to the habitat. The more advanced the succession, i.
e., the degree of stabilisation, the greater the climatic or
physiographic change necessary to disturb it, with the re-
sult that such disturbances are much more frequent in the
earlier stages than in the later development. Constant,
gradual movement toward a stable formation is characteris-
tic of continuous succession (successio continua). Contrasted

KINDS 123

with this is intermittent succession (successio intermissa), in
which the succession swings for atime in one direction, from
xerophytic to mesophytic for example, and then moves in
the opposite direction, often passing through the same
stages. This phenomenon usually is characteristic only of
the less stable stages, and is generally produced by a
climatic swing, in which a series of hot or dry years is
followed by one of cold or wet years, or the reverse. The
same effect upon a vast scale is produced by alternate eie-
vation and subsidence, but these operate through such great
periods of time that one can not trace, but can only conjec-
ture their effects. A normal continuous succession fre-
quently changes its direction of movement, or its type, in
transitiun regions or in areas where the outposts of a new
flora are rapidly advancing, as in wide mesophytic valleys
that run down into or traverse plains. Here the change is
often sudden, and grass and desert formations are replaced
by thickets and forests, resulting in abrupt succession
(successio abrupta). Species guilds are typical examples of
this. More rarely, a stage foreign to the succession will be
interpolated, replacing a normal stage, or slipping in be-
tween two such, though finally disappearing before the next
regular formation. This may be distinguished as inter-
polated succession (successio interpolata).

The apparent terminus of all stabilisation is the forest,
on account of the thoroughness with which it controls the
habitat. A close examination of vegetation, however, will
show that its stable terms are dependent in the first degree
upon the character of the region in which the formation is
indigenous. It is obviously impossible that successions in
desert lands, in polar barrens, or upon alpine stretches
should terminate in forest stages. In these, grassland must
be the ultimate condition, except in those extreme habitats.
alpine and polar, where mosses and lichens represent the
highest type of existing vegetation. Forests are ultimate
for all successions in habitats belonging to a region
generally wooded, while grassland represents the terminus

124 SUCCESSION

of prairie and plains successions as well as of many arctic-
alpine ones.
CAUSES AND REACTIONS.

The initial cause of a succession must be sought ina
physical change in the habitat: its continuance depends up-
on the reaction which each stage of vegetation exerts upon
the physical factors which constitute the habitat. A single
exception to this is found in anomalous successions, where
the change of formation often hinges upon the appearance
of remote or foreign disseminules. The causes which initi-
ate successions have already been considered: they may be
summarised as follows: (1) weathering, (2) erosion, (3) ele-
vation, (4) subsidence, (5) climatic changes, (6) artificial
changes. The effect of succeeding stages of vegetation up-
on a new or denuded habitat usually finds expression ina
change of the habitat with respect to a particular factor,
and in a definite direction. Often, there is a primary re-
action, and one or more secondary ones, which are corol-
laries of it. Rarely, there are two or more coordinate re-
actions. The general ways in which vegetation reacts upon
the habitat are the following: (1) by preventing weathering;
(2) by binding aeolian soils; (3) by reducing run-off and pre-
venting erosion; (4) by filling with silt, and plant remains;
(5) by enriching the soil; (6) by exhausting the soil; (7) by
accumulating humus; (8) by modifying atmospheric factors.
The direction of the movement of a succession is the im-
mediate result of its reaction. From the fundamental
nature of vegetation, it must be expressed in terms of water
content. The reaction is often so great that the habitat
undergoes a profound change in the course of the suc-
cession, changing from hydrophytic to mesophytic or
xerophytic, or the reverse. This is characteristic of newly
formed or exposed soils. Such successions are xerotropic
(énpés, Ary, tpords turning), mesotropic, or hydrotropic, ac-
cording to the ultimate condition of the habitat. When the
reaction is less marked, the type of habitat does not change
materially, and the successions are zerostatic, (orariuds
stopping) mesostatic, or hydrostatic, depending upon the

REACTIONS 125

water content. Such conditions obtain for the most part
only in denuded habitats.

(1) Succession by preventing weathering.
Reactions of this nature occur especially in alpine and boreal
regions, in the earlier stages of lichen-moss successions.
They are typical of igneous and metamorphic rocks in which
disintegration regularly precedes decomposition. The
influence of the vegetation is best seen in the lichen stages,
where the crustose forms make a compact layer, which dim-
inishes the effect of the atmospheric factors producing disin-
tegration. In alpine regions especially, this protection is so
perfect that the crustose lichens may almost be regarded as
the last stage of a succession. There are no recorded ob-
servations which bear upon this point, but it seems certain
that the pioneer rock lichens, Lecanora, Lecidea, Biatora,
Buellia and Acarospora, cover alpine rocks for decades, if not
for centuries. Ultimately, however, the slow decomposition
of the rock surface beneath the thallus has its effect. Tiny
furrows and pockets are formed, in which water accumulates
to carry on its ceaseless work, and the compact crustose
covering is finally ruptured, permitting the entrance of
foliose forms. The latter, like the mosses, doubtless pro-
tect rock surfaces, especially those of the softer rocks, in a
slight degree against the influence of weathering, but this
is more than offset by their activity in hastening decompo-
sition, and thus preparing a field for invasion. Rocks and
boulders (petria, petrodia, phellia) furnish the best examples
of this reaction: cliffs (cremnia) usually have a lichen cover-
ing on their faces, while the forces which produce disinte-
gration operate from above or below.

(2) Succession by binding aeolian soils.
Dunes (thinia) are classic examples of the reaction of
pioneer vegetation upon habitats of wind-borne sand. The
initial formations in such places consist exclusively of sand-
binders. plants with masses of fibrous roots, and usually
also with strong rootstalks, long, erect leaves and a
vigorous apical growth. They are almost exclusively per-
ennial grasses and sedges, possessing the unique property

126 SUCCESSION

of pushing up rapidly through a covering of sand. They
react by fixing the sand with their roots, thus preventing
its blowing about, and also by catching the shifting particles
among their culms and leaves, forming a tiny area of
stabilisation, in which the next generation can establish a
foothold. The gradual accumulation of vegetable detritus
serves also to enrich the soil, and makes possible the advent
of species requiring better nourishment. Blowouts
(anemodia) are almost exact duplicates of dunes in so far as
the steps of revegetation are concerned: while one is a
hollow, and the other a hill, in both the reaction operates
upon a wind-swept slope. Sandhills (amathia) and deserts
(eremia) show similar though less marked reactions, except
where they exhibit tynical inland dunes. Sandbinders,
while usually classed as xerophytic or halophytic, are in
reality dissophytes. Their roots grow more or less super-
ficially in moist sand, and are morphologically mesophytic,
while their leaves bear the stamp of xerophytes. The
direction of movement in successions of this kind is
normally from xerophytes to mesophytes, i. e., it is
mesotropic. In sandhills and deserts, the succession oper-
ates wholly within the xerophytic (dissophytic) series.
Along sea coasts, the mesophytic terminus is regularly
forest, except where forests are remote, when it is grass-
land.

(3) Succession by reducing run-off, and
preventing erosion. All bare or denuded habitats
that have an appreciable slope are subject to erosion by
surface water. The rapidity and degree of erosion depend
upon the amount of rainfall, the inclination of the slope, and
the structure of the surface soil. Regions of excessive
rainfall, even where the slope is slight, show great though
somewhat uniform erosion: hill and mountain are deeply
eroded even when the rainfallis small. Sloves consisting of
compact eugeogenous soils, notwithstanding the marked
adhesion of the particles, are much eroded where the rain-
fali is great, on account of the excessive run-off. Porous
dysgeogenous soils, on the contrary, absorb most of the

REACTIONS 127

rainfall; the run off is small and erosion slight, except
where the slope is great, a rare condition on account of the
imperfect cohesion of the particles. In compact soils, the
plants of the initial formations not merely break the impact
of the rain-drops, but, what is much more important, they
delay the downward movement of the water, and produce
numberless tiny streams. The delayed water is largely
absorbed by the soil, and the reduction of the run-off pre-
vents the formation of rills of sufficient size to cause
erosion. As in dunes, such plants are usually perennial
grasses, though composites are frequent: the root system is,
however, more deeply seated, and a main or tap root is often
present. On sand and gravel sloves, the loose texture of
the soil results generally in the production of sandbinaers
with fibrous roots. Unlike dunes, such slopes exhibit a
large number of mats and rosettes with tap roots, which are
effective in preventing the slipping or washing of the sand,
and run little danger of being covered, as is the case with
dune-formers. In both instances, each pioneer plant serves
asa center of comparative stabilisation for the establish-
ment of its own offspring, and of such invaders as find their
way in. From the nature of these, slopes almost invariably
pass through grassland stages before finding their termini
in thickets or forests. Bad lands (hydrotribia) furnish the
most striking examples of eroded habitats. The rainfall in
the bad lands of Nebraska and South Dakota is small (300
mm.); yet the steepness of the slope and the compactness of
the soil render erosion so extreme, that it is all but im-
possible for plants to obtain a foothold. Their reaction is
practically negligible, and the vegetation passes the pioneer
stages only in the relatively stable valleys. Mountain
slopes (ancia), and ridges and hills (Jophia) are readily eroded
in new or denuded areas. This is especially true of hill and
mountain regions, which have been stripped of their forest
or thicket cover by fires, lumbering, cultivation or grazing.
Where the erosion is slight, the resulting succession may
show initial xerophytic stages, or it may be completely
mesostatic. Excessively eroded habitats are xerostatic, as

128 SUCCESSION

in the case of bad lands, or, more frequently, they are
mesotropic, passing first through a long series of xerophytic
formatiuns. Sandbars (cheradia, syrtidia) should be con-
sidered here, though they are eroded by currents and
waves, and not by run-off. They are fixed and built up by
sand-binding grasses and sedges, usually of a hydrophytic
nature, and pass ultimately into mesophytic forest.

(4) Succession by filling with silt, and
plant remains. All aquatic habitats into which silt,
wash, or other detritus is borne by streams, currents, floods,
waves or tides are slowly shallowed by the action of the
water plants present. These not only check the movement
of the water, thus greatly decreasing its carrying power,
and causing the deposition of a part or all of its load, but
they also retain and fix the particles deposited. In accord-
ance with the rule, each plant becomes the center of a
stabilising area, which rises faster than the rest of the
floor, producing the well-known hummocks of lagoons and
swamps. All aquatics produce this reaction. It is more
pronounced in submerged and amphibious forms than in
floating ones, and it takes place more rapidly with greatly
branched or dissected plants than with others. In pools
(tiphia) and lakes (limnia), debouching streams and surface
waters deposit their loads in consequence of the check ex-
erted by the still water and the marginal vegetation, and
delta-like marshes are quickly built up by filling. Springs
(crenia) likewise form marshes where they gush forth in
sands, the removal of which is impeded by vegetation.
The flood plains and deltas of rivers show a similar reaction.
The heavily-laden flood waters are checked by the vege-
tation of meadows and marshes, and deposit most of their
load. The banks of streams (ochthia) and of ditches
(taphria) are often built up in the same fashion by the action
of the marginal vegetation upon the current. The pre-
sence of marginal vegetation often determines the checking
or deflecting of the current in such a way as to initiate
meanders, while natural levees owe their origin to it, in
part at least. Along low sea coasts, waves and tides hasten

REACTIONS 129

the deposit of river-borne detritus, causing the water to
spread over the lowlands and form swamps. They often
throw back also the sediment that has been deposited in the
sea, the marsh vegetation acting asa filter in both cases.
Successions of the kind indicated above are regularly meso-
tropic. Where the soil is sandy, and the filling-up process
sufficiently great, or where salts or humus occur in excess,
xerophytic formations result. In certain cases, these suc-
cessions appear to be permanently hydrostatic, changing
merely from floating or submerged to amphibious con-
ditions, but this is probably due to the slowness of the re-
action. As a rule, the accumulation of plant remains is
relatively slight, and plays an unimportant part in the re-
action. In peat bogs and other extensive swamps, the
amount of organic matter is excessive, and plays an import-
ant réle in the building up of the swamp bed. Its greatest
reaction, however, results frum its partial decomposition
under water. This process sets free a number of so-called
humous acids, which inhibit the absorption of water, and
cause the development of xerophytes in what are apparently
hydrophytic habitats.

(5) Succession by enriching the _ soil.
This reaction occurs to some degree in the great majority
of all successions. The relatively insignificant lichens and
mosses produce this result upon the most barren rocks,
while the higher forms of later stages, grasses, herbs,
shrubs, and trees, exhibit it in marked progression. The
reaction consists chiefly in the incorporation of the decom-
posed remains of each generation and each stage in the soil.
A very important part is played by the mechanical and
chemical action of the roots in breaking up the soil
particles, and in changing them into soluble substances.
Mycorrhizae, bacterial nodules and especially soil bacteria
play a large part in increasing the nutrition content of the
soil, but the extent to which they are effective in succession
iscompletely unknown. The changes in the color, texture
and food value of the soil in passing from the initial to
ultimate stages of a normal succession are well-known, and

130 SUCCESSION

have led many to think them the efficient reactions of such
successions. It seems almost certain, however, that this is
merely a concomitant, and that, even in anomalous succes-
sions where facies replace each other without obvious
reasons, the reactions are concerned more with water con-
tent, light and humidity than with the food content of the
soil.

(6) Succession by exhausting the soil.
This is a reaction not at all understood as yet in nature. A
number of phenomena, such as the “‘fairy rings’’ of mush-
rooms and other fungi, the peripheral growth and central
decay of lichens, Lecanora, Placodium, Parmela, and of mat-
forming grasses, such as Muhlenbergia, and the circular
advance of the rootstalk plants, indicate that certain plants
at least withdraw much of the available supply of some
essential soil element, and are forced to move away from
the exhausted area. It is probable that the constant shift-
ing of the individuals of a formation year after year, a
phenomenon to be discussed under alternation, has some
connection with this. It will be impossible to establish such
a relation, however, until the facts are exactly determined
by the method of quadrat statistics. So far as native for-
mations are concerned, there cannot be the slightest ques-
tion that prairies and forests have existed over the same
area for centuries without impoverishing the soil in the
least degree, a conclusion which is even more certain for
the open vegetation of deserts and plains. With culture
formations, the case is quite different. The exhaustion of
the soil by continuous or intensive cultivation is a matter of
common experience in all lands settled for a long period.
Calcium, phosphorus, and nitrogen compounds especially
are used up by crops, and must be supplied artificially. The
reason for this difference in reaction between native and
culture formations seems evident. In harvesting, not
merely the grain, but the stems and leaves, and in gardening
often the root also, are removed, so that the plant makes
little or no return to the soil. In nature, annual plants re-
turn to the ground every year all the solid matter of routs,

REACTIONS 131

stems, leaves and fruits, with the exception of the relatively
small number of seeds that germinate. ‘Perennial herbs
return everything but the persistent underground parts:
shrubs and trees replace annually an immense amount of
material used in leaves and fruits, and sooner or later by
the gradual decay of the individuals, or by the destruction
of the whole formation, they restore all that they have
taken from the soil. This balance is further maintained to
an important degree by the activity of the roots, which take
from the deep-seated layers of the soil the crude materials
necessary for the formation of leaves and fruits. Upon the
fall and decay of these, their materials are incorporated
with the upper layers of the formation floor, from which
they may be absorbed by the undergrowth, or find their way
again into the layers permeated by the tree roots. From
the universal occurrence of weeds in cultivated regions, the
pioneers in impoverished or exhausted fields are uniformly
ruderal plants. As is well-known, the seed production and
ecesis of these forms are such that they take pussession
quickly and completely, while their demands upon the soil
are of such a nature that the most sterile field can rapidly
be covered by a vigorous growth of weeds. As indicated
elsewhere, ruderal formations ultimately yield to the native
vegetation, though in regions so completely given over to
culture that native formations are lacking or remote, it is
probable that successions reach their final stage within the
group of ruderal plants.

(7) Succession by the accumulation of
humus. Thisis the characteristic reaction of peat bogs,
and cypress swamps (oyilia), in which the accumulation of
vegetable matter is enormous. The plant remains decom-
pose slowly and incompletely under the water, giving rise
to the various humic acids. These possess remarkable
antiseptic qualities, and have an injurious effect upon pro-
toplasm. Like alkalies, they hinder the absorption of
water by the root hairs, though this is also due in part to poor
aeration, and in consequence call forth xerophytic modifi-
cations. The same tendency exists in practically all inland

132 SUCCESSION

marshes and swamps, but the quantity of decomposing
vegetation in many is not great enough to produce an
efficient reaction. The characteristic plants of peat bogs
and humus swamps are xerophytes, which possess a super-
ficial root system: structurally, they are almost identical
with dissophytes. The occurrence of xerophytes in situ-
ations typically hydrophytic is no longer a puzzling contra-
diction of the unique value of water content in the control
of vegetation. It is readily explained by the reduction of
the available water, and by the lack of proper aeration in
the presence of humic acids. Formations of this type
usually start as freshwater swamps. The succession is con-
sequently xerotropic, but no thorough study of its stages
has as yet been made.

(8) Succession by modifying atmospherie
factors. All layered furmations, forests, thickets, many
meadows and wastes, etc., show reactions of this nature, and
are in fact largely or exclusively determined by them. The
reaction is a complex one, though it is clear that light is
the most efficient of the modified factors, and that humidity,
temperature, and wind, while strongly affected, play subord-
inate parts. In normal successions, the effect of shade,
i. e., diffuse light, enters with the appearance of bushes or
shrubs, and becomes more and more pronounced in the
ultimate forest stages. The reaction is exerted chiefly by
the facies, but the effect of this is to cause increasing
diffuseness in each successively lower layer, in direct ratio
with the increased branching and leaf expansion of the
plants in the layer just above. In the ultimate stage of
many forests, especially where the facies are reduced to
one, the reaction of the primary layer is so intense as to
preclude all undergrowth. Anomalous successions often
owe their origin to the fact that certain trees react in such
a way as to cause conditions in which they produce seedlings
with increasing difficulty, and thus offer a field favorable to
the ecesis of those species capable of enduring the dense
shade. Successions of this kind are almost invariably

LAWS 133

mesostatic, as it is altogether exceptional that layered for-
mations are either xerophytic or hydrophytic.
LAWS OF SUCCESSION.

The investigation of succession has so far been neither
sufficiently thorough nor systematic to permit the postu-
lation of definite laws. Enough has been done, however, to
warrant the formulation of a number of rules, which apply
to the successions studied, and afford a convenient method
for the critical investigation of all successions upon the
basis of initial causes, and reactions. Warming has already
brought together a few such rules, and an attempt is here
made to reduce the phenomena of succession, including its
causes and effects, toa tentative system. At present it is
difficult to make a thoroughly satisfactory classification of
such rules, and they are here arranged in general conform-
ity with the procedure in succession.

I. Causation. The initial cause of a succession is the for-
mation or appearance of a new habitat, or the efficient
change of an existing one.

I. Reaction. Hach stage reacts upon the habitat in such
a way aS to produce physical conditions more or less
unfavorable to its permanence, but advantageous to
the invaders of the next stage.

I. Proximity and Mobility.

(1) The pioneers of @ suceession are those species
nearest at hand that are the most mobile.

(2) The number of migrants from any formation into a
habitat varies inversely as the square of the dis-
tance.

(3) The pioneer species are regularly derived from
different formations, as the latter nearly always con-
tain permobile species capable of effective ecesis.

(4) The plants of the initial stages are normally algae
and fungi, with minute spores, composites and
grasses, which possess permobile fruits, or ruderal
plants, on account of their great seed production.

IV. Ecesis.

(1) All the migrants into a new, denuded, or greatly

134

(2)

(3)

(4)

(5)

(6)

(7)

SUCCESSION

modified habitat are sorted by ecesis into three
groups: (1) those that are unable to germinate or
grow, and soon die; (2) those that grow normally
under the conditions present; (3) those that pass
through one or more of the earlier stages in a dor-
mant state to appear at a later stage of the suc-
cession.

Wherever ruderal vegetation is present, it con-
tributes a large number of the pioneer species of
each succession, on account of the thorough ecesis.
In other regions, this part is played by subruderal
native species.

Annuals and biennials are characteristic of the early
stages of secondary successions, on acount of their
great seed production and ready ecesis.

In layered formations, heliophytes appear before
sciophytes: they ultimately yield to the latter, ex-
cept where they are able to maintain a position in
the primary layer.

Excessive seed production and slight mobility lead
to the imperfect ecesis of individuals in dense stands,
and in consequence usually produce great instability.
Each pioneer produces about itself a tiny area of
ecesis and stabilisation for its own offspring, for the
disseminules of its fellows, or of invaders.

Species propagating by offshoots, or producing re-
latively immobile disseminules in small number,
usually show effective ecesis, as the offspring appear
within the area of the reaction of the parent forms.

V. Stabilisation.

(1)
(2)

Stabilisation is the universal tendency of vegetation.
The ultimate stage of a succession is determined by
the dominant vegetation of the region. Lichen for-
mations are often ultimate in polar and niveal zones:
grassland is the final vegetation for plains and alpine
stretches, and for much prairie, while forest is the
last stage for mesophytic midlands and lowlands, as
well as for subalpine regions.

(3)

(4)

(5)

LAWS 135

Grassland or forest is the usual terminus of a suc-
cession: they predominate in lands physiographically
mature.
The limit of a succession is determined in large part
by the progressive increase in occupation, which
makes the entrance of invaders more and more diffi-
cult.
Stabilisation proceeds radiately from the pioneer
Jants or masses. The movement of offshoots is
awav from the parent mass, and the chances of ecesis
are greatest near its edges, in a narrow area in which
the reaction is still felt, and the occupation is not
exclusive.

VI. General Laws.

(1)

(2)
(3)

(4)

(5)

The stages, or formations, of a succession are dis-
tinguished as initial (prodophytia), intermediate
(ptenophytia), and ultimate (aiphytia).

Initial formations are open, ultimate formations are
closed.

The number of species is small in the initial stages.
It attains a maximum in intermediate stages, and
again decreases in the ultimate formation, on ac-
count of the dominance of a few species.

The normal sequence of vegetation forms in suc-
cession is: (1) algae, fungi, mosses; (2) annuals and
biennials; (8) perennial herbs; (4) bushes and
shrubs; (5) trees.

The number of svecies and of individuals in each
stage increases constantly up to a maximum, after
which it gradually decreases before the forms of the
next stage. The interval between two maxima is
occupied by a mixed formation.

(6) A secondary succession does not begin with the in-

(7)

itial stage of the primary one which it replaces, but
usually at a much later stage

At present, successions are generally mesotropic,
grassland and forest being the ultimate stages,
though many are xerostatic or hydrostatic. If

136 SUCCESSION

erosion continue until the sea level is reached, the
ultimate vegetation of the globe will be hydrophytic.
Should the heat of the sun decrease greatly before
this time, the last vegetation will be xerophytic, i. e.
crymophytic.

(8) The operation of succession was essentially the same
during the geological past as it is today: from the
nature of their vegetation forms, the record deals
largely with the ultimate stages of such successions.

CLASSIFICATION AND NOMENCLATURE.

New or denuded habitats arise the world over by the oper-
ation of the same or similar causes, and they are revegetated
in consequence of the same reactions. Similar habitats
produce similar successions. The vegetation forms and
their sequence are usually identical, and the genera are fre-
quently the same, or corresponding im regions not entirely
unrelated. The species are derived from the adjacent
vegetation, and, except in alpine and coast regions, are
normally different. The primary groups of successions are
determined by essential identity of habitat or cause, e. g.,
aeolian successions, erosion successions, burn successions,
etc. When they have been more generally investigated, it
will be possible to distinguish subordinate groups of suc-
cessions, in which the degree of relationship is indicated
by the similarity of vegetation forms, the number of
common genera, etc. For example, burn successions in the
Ural and in the Rocky mountains show almost complete
similarity in the matter of vegetation forms, and their se-
quence, and have the majority of their genera in common.
A natural classification of successions will divide them first
of all into normal and anomalous. The former fall into two
classes, primary and secondary, and these are subdivided in-
to a number of groups, based upon the cause which initiates
the succession.

The need of short distinctive names of international value
for plant formations is obvious: it has become imperative
that successions also should be distinguished critically, and
designated clearly. From the very nature of the case, it is

CLASSIFICATION AND NOMENCLATURE 137

impossible to designate each formation or succession by a
single Greek or Latin term, as habitats of the same char-
acter will show in different parts of the world a vegetation
taxonomically very different. It may some day be possible
to use a binomial or trinomial for this purpose, somewhat
after the fashion of taxonomy, in which the habitat name
will represent the generic idea as applied to formations, and
a term drawn from the floristic impress the specific idea.
Such an attempt would be futile or valueless at the present
time: it could not possibly meet with success until there is
more uniformity in the concept of the formation, and until
there has been much accurate and thorough investigation of
actual formations, a task as yet barely begun. At present, it
seems most feasible as well as scientific, to designate all for-
mations occupying similar habitats by a name drawn from the
character of the latter, such as a meadow formation, poium, a
a forest formation, hylium, a desert formation, eremium, ete.
A particular formation is best designated by using the
generic name of one or two of its most important species in
conjunction with its habitat term, as Spartina-Elymus-poium,
Picea-Pinus-hylium, Cereus-Yucca-eremium, etc. Apparently
a somewhat similar nomenclature is adapted to successions.
The cause which produces a new habitat may well furnish
the basis for the name of the general groups of successions,
as pyrium (literally, a place or a habitat burned over), a
burn succession, tribium, an erosion succession, etc. A burn
succession consists of a sequence of certain formations in
one part of the world, and of a series of quite different ones,
floristically, in another. A particular burn succession
should be designated by using the names of a characteristic
facies of the initial and ultimate stages in connection with
the general term, e. g., Bryum-Picea-pyrium, etc. A tri-
nomial constructed in this way represents the desirable
mean between definition and brevity. Greater definiteness
is possible only at the expense of brevity, while to shorten
the name would entirely destroy its precision. The follow-

‘Clements, F. E. A System of Nomenclature for Phytogeography.
Engler 31:b5 1902.

138 SUCCESSION

ing classification of successions is proposed, based upon the
plan outlined above. The termination -iwm (-cov) has been
used throughout in the construction of names for suc-
cessions, largely for reasons of euphony. If it should be-
come desirable to distinguish the names of formations and
successions by the termination, the locative suffix -on(-ov)
should be used for the latter. Theterms given below would
then be hypson, rhyson, hedon, sphyron, prochoson, pnoon,
pagon, tribon, cluson, repon, olisthon, xerasion, theron, broton,
pyron, ecballon, camnon, ocheton, ardon.
I. Normal successions: cyriodochae (xivpus, regular, dox%, 7,
succession)
a. Primary successions: protodochae (zpéros, first, pri-
mary)
1. By elevation: hypsium (tos, ro, height, elevation,
-elov, place)
2. By voleanic action: rhysium (fvois, 7, flowing, es-
pecially of fire)
3. In residuary soils: hedium (éos, ro, a sitting, base)
4. In colluvial soils: sphyrium (c¢upov, ré, ankle, talus)
5. In alluvial soils: prochosium (zpéxwos, 7, a deposition
of mud)
6. In aeolian soils: pnoium (voy, 4, blowing, blast)
7. In glacial soils: pagium (zéyos, 6, that which becomes
solid, i. e., a glacier)
b. Secondary successions: hepodochae (éra, to follow)
8. In eroded soils: tribium (tpBw, wear or rub away)
9. In flooded soils: clusium (xAvois, 6, a drenching, flood-
ing)
10. By subsidence: repium (fére, incline downwards,
sink)
11. In landslips: olisthium (é6dc@0s, 6, slip)
12. In drained and dried out soils: xerasium (fypacm, 9,
drought)
13. By animal agencies: therium (@yp, 6, wild animal)
14, By human agency: brotium (8pords, 6, a mortal)
a. Burns: pyrium (zip, 7é, fire)
b. Lumbering: ecballium (éfdAd\w, cut down forests)

CLASSIFICATION AND NOMENCLATURE 139

c. Cultivation: camnium (xépve, cultivate)

d. Drainage: ochetium (éxerés, 6, drain)

e. Irrigation: ardium (dpsw, irrigate)
II. Anomalous successions: xenodochae (éé0s, strange, un-

usual)
The following series will illustrate the application of this

system of nomenclature to particular successions, and their
stages, or formations.

Thliaspi-Picea-sphyrium : pennycress-spruce talus succession
Thlaspi-Eriogonum-chalicium: pennycress-eriogonum gravel slide

formation

Elymus-Gilia-chalicodium : wildrye-gilia half gravel slide for-
mation

Quercus-Holodiscus-lochmodium : oak-fringewood dry thicket for-
mation

Pinus-xerohylium : pine dry forest formation
Picea-Pseudotsuga-hylium : spruce-balsam forest formation

Bryum-Picea-pytium : moss-spruce burn succession
Bryum-telmatium : moss meadow formation
Aster-Chamaenerium-poium : aster-fireweed meadow formation
Deschampsia-Carex-poium : hairgrass-sedge meadow formation
Salix-Betula-helolochmium : willow-birch meadow thicket for-

mation
Populus-hylium : aspen forest formation
Picea-hylium : spruce forest formation
Lecanora-Carex-hedium ; lichen-carex residuary succession
Lecanora-Gyrophora-petrium : crustose lichen rock formation
Parmelia-Cetraria-chalicium : foliose lichen gravel slide for-
mation

Paronychia-Silene-chalicodium : nailwort-campion gravel slide
formation

Carex-Campanula-coryphium : sedge-bluebell alpine meadow for-
mation

Eragrostis-Helianthus-xerasium : eragrostis-sunflower drainage

succession
Eragrostis - Polygonum - telmatium : eragrostis - heartsease wet
meadow formation —
Helianthus-Ambrosia-chledium : sunflower-ragweed waste for-
mation
INVESTIGATION OF SUCCESSION.

The study of succession must proceed along two funda-
mental lines of inquiry. It is necessary to investigate

140 SUCCESSION

quantitatively the physical factors of the initial stages, and
the reactions produced by the subsequent stages. This
should be done by automatie instruments for humidity,
light, temperature and wind, in order that a continuous
record may be obtained. Water content and precipitation
readings are taken daily or even less frequently, while soil
properties, and physiographic factors, altitude, slope, sur-
face and exposure, are determined once forall. It is equally
needful to determine the development and structure of
each stage with particular reference to the adjacent for-
mations, to the stage that has just preceeded, and the one
that is to follow. For this, the use of the permanent
quadrat is imperative, as the sequence and structure of the
stages can be understood only by a minute study of the
shifting and rearrangement of the individuals. In the ex-
amination of successions, since cause and effect are so
intimately connected in each reaction, it is especially im-
portant that general and superficial observations upon
structure and sequence be replaced by precise records, and
that vague conjectures as to causes and reactions be sup-
planted by the accurate determination of the physical fact-
ors which underly them.

The period of time through which a primary succession
operates is usually too great to make its complete study
possible within a single lifetime. Secondary successions
run their course much more quickly, and a decade will some-
times suffice for stabilisation, though even here the period
is normally longer. The longest and most complex suc-
cession, however, may be accurately studied in a region,
where several examples of the same succession occur in
different stages of development. In the same region, the
physical factors of one example of a particular succession
are essentially identical with those of another example in
the same stage. If one is in an initial stage, and the other
in an intermediate condition, the development of the former
makes it possible to reestablish more or less completely the
life history of the latter. The same connection may be

BIBLIOGRAPHY 141

made between intermediate and ultimate stages, and it is
thus possible to determine with considerable accuracy and
within a few years the sequence of stages in a succession
that requires a century or more for its complete develop-
ment. In the Roeky mountains, gravel slides (talus slopes)
are remarkably frequent. They occur in all stages of de-
velopment, and the alternating slides of different ages fur-
nish an almost perfect record of this succession. This
method lacks the absolute finality which can be obtained by
following a succession in one spot from its inception to final
stabilisation, but it is alone feasible for long successions, i.
e., those extending over a score or more of years. When it
comes to be universally recognized asa plain duty for each
investigator to leave an exact and complete record in
quadrat maps and quadrat photographs of the stages
studied by him, it will be a simple task for the botanists of
one generation to finish the investigation of the successions
begun by their predecessors.
BIBLIOGRAPHY
1749 Biberg, I. J. Oeconomia Naturae. Amoen.
Acad. 4:1
1820 De Candolle, A. P. Essai Elémentaire de Géogra-
phie Botanique 27
1842 Steenstrup, J. Geognostisk-geologisk-Under-
sdgelse i det nordlige
Sjalland
1844 Berg, EH. v. Das Verdringen der Laub-
wilder durch die Fichte
und Kiefer. Grisebach
Berichte 1844 : 15

1850 Humboldt, A. v. Views of Nature 125, 213

1851 Vaupell, C. De Nordsjaellandske
Skovmoser

1852 Henfrey, A. The Vegetation of Europe 67

1855 De Candolle, A. Géographie Botaniaue Rais-
onnée 743

1856 Hofmann Der nordliche Ural und das

Kistengebirge Pae-Choi

142

1858
1859

1863
1864
1865
1871

1879
1881

1884
1885

1887

1888

1889

Hill
Stossner, A.

Kerner, A.

Middendorff, A.
Kabsch, W.
Miller, P. E.
Engler, A.
Hult, R.

Gronlund, C.

Hult, R.

Callmé, A.

Treub, M.

Senft, F.
Krassnoff, A.

Fliche, M. P.

Tanfiljew, G.

SUCCESSION

Reise in Sibirien

Vegetationsverhaltnisse von
Annaberg und Umgebung

Das Pflanzenleben der Donau-
lander

Die Gewiachse Sibiriens

Das Pfianzenleben der Erde

Bjargfyrren (Pinus montana)
Tidskr. pop. Fremst.

Versuch einer LEntwick-
lungsgeschichte der Pflan-
zenwelt

Forsok till analytisk behand-
lung af formationerna
Medd. Soc. Fenn. 8

Plantevaxten paa Island.
Nat. For. Festschr. 1884-90

Blekinges vegetation. Just
85 : 812

Die alpinen Pflanzenforma-
tionen des ndrdlichstens
Finnlands. Engler 11 : b6l1

Om de nybildade Hjelmar-
déarnes vegetation. Bihang
Sv. Vet. Akad. Handl. XII

Notice sur la nouvelle flore
de Krakatau. Ann. Jard.
Buit. 7

Der Erdboden. Just °88: 45

Bemerkungen iiber die Vege-
tation des Altai. Engler
9:53

Un reboisement, étude bot-
anique et forestiére.
Engler 11: 104

Uber die Sumpfe des Gouv.
Petersburgs. Engler 24:68

1890

1891

1892

1893

BIBLIOGRAPHY 143

Douglas, R.

Warming, E.

Kihlmann, A. C.

Klinge, J.

Kerner, A.
Korschinsky, S.

Warming, E.

Weber, C.

Krause, E. H. L.
Blytt, A.

Sernander, R.

Grevillus, A. Y.

Krause, EB. H. L.

Succession of Forest Growth.
Gard. Chron. ’89: 10. Just
89: 172

Fra Vesterhavskystens Mars-
kegne. Vid. Medd. Foren.
1890

Pflanzenbiologisch Studien
aus Russisch-Lappland

Uber den Einfivss der
mittleren Windrichtung auf
das Verwachsen der
Gewisser. Engler 11 : 264

Pfianzenleben. 1: 267, 4: 895

Uber die Entstehung und das
Schicksal der Hichenwalder
in mittleren Russland.
Engler 13: 471

De psammofile Vegetationer
in Danmark. Vid. Medd.
Foren.

Uber die Zusammensetzung
des natiirlichen Graslandes.
Engler 16: b56

Die Heide. Engler 14: 515

Uber zwei Kalktuffbildungen
in Gudbrandsdalen. Engler
16: bl

Die EBinwanderung der Fichte
in Scandinavien. Engler
15:1

Om vegetationens utveckling
pa de nybildade Hjelmar-
oarne. Bot. Cent. Beih.
5: 36

Beitrag zur Geschichte der
Wiesenflora in ;Norddeut-
schland. Engler 15: 387

144

1894

1895

1896

- 1897

Stebler, F. G. &
Schroter, C.

Wojeikow

Flahault, C. &
Combres, P.

Weber, C.

Warming, E.

Graebner, P.

Meigen, F.

Grevillius, A. Y.

Nilsson, A.

Meigen, F.

MacMillan, C.

Merrill, G. P.

SUCCESSION

Beitrage zur Kenntniss der
Matten und Weiden der
Schweiz. Engler 17: b17

Die Einwirkung des Mens-
chen auf die Natur. Engler
24: 69

Sur la flore de la Camargue-
Bull. Soc. Bot. Fr. 41: 37

Uber Verainderungen in der
Vegetation der Hochmoore
unter dem Hinfiusse der
Cultur. Engler 23: b15

Plantesamfund, Grundtrok af
den oekologiske Plante-
geografi. 352, 363, 370

Studien itiber die norddeut-
schen Heide. Engler 30:500

Beobachtungen iiber For-
mationsfolge bei Freyburg
a. d. Unstrut. Deut. Bot.
Monat. 13

Die erste Pflanzenansiedelung
auf den Reblausherde. ib.

Studier dfver vegetationens
sammansattning. Sver.
Geol. Unders. 144.

Om ortrika barrskogar. Tids.
Skog. 93

Die Besiedlung der Reblaus-
herde in der Provinz Sach-
sen. Engler 21: 212

On the Formation of Circular
Muskeag in Tamarack
Swamps. Torr. Bull. 23:
500

Rocks, Rock-weathering and
Soils. |

1898

1899

1900

1901

1902

BIBLIOGRAPHY 145

Pound, R. &
Clements, F. E.

Graebner, P.

Cowles, H. C.

Nilsson, A.

Gerhardt, J.

Meigen, F.

Cowles, H. C.

Elmore, C. J.

Whitford, H. N.

Weber. C. A.

Clements, F. E.

The Phytogeography of Ne-
braska.

Uber die Bildung natiirlichen
Vegetationsformationen in

norddeutschen Flachlande.
Bot. Cent. 77: 212

The Ecological Relations of
the Sanddunes of Lake
Michigan. Bot. Gaz. 27: 95

Nagra drag ur de svenska
vaxtamhiallenas utveck-
lingshistoria. Bot. Cent.
1900: 370

Handbuch des _ deutschen
Diinenbaues.

Beobachtungen itiber Forma-
tionsfolge im Kaiserstuhl.
Deut. Bot. Monat. 18: 145

The Physiographic Ecology
of Chicago and Vicinity.
Bot. Gaz. 31: 73

Flora of a Dried-up Millpond.
Proc. Nebr. Acad. Sci.
7: 29,69

The Genetic Development of
the Forests of Northern
Michigan. Bot. Gaz. 31: 289

Uber die Erhaltung von
Mooren und Heiden Nord-
deutschlands in Naturzu-
stande. Abh. Nat. Ver.
Bremen 15: 263

‘Herbaria Formationum Colo-

radensium,

A System of Nomenclature
for Phytogeography.
Engler 31: bl

146

Drude, O.

Graebner, P.
Weber, C. A.

SUCCESSION

Der Hercynische Florenbe-
zirk

Die Heide Norddeutschlands.

Uber die Vegetation und
Entstehung des Hochmoores
von Augstumal.

ZONATION

The recognition of vegetation zones dates from Tourne-
fort (1717), who found that, while the plauts of Armenia
occupied the foot of Mount Ararat, the vegetation of the
slopes above contained many species of southern Europe:
still higher appeared a flora similar to that of Sweden, and
on the summit grew arctic plants, such as those of Lapland.
Linné (1751) generalised this idea in the dictum, ‘‘Plante
diversee indicant altitudinem perpendicularem terre.’’ Ratmond
(1801) studied the vegetation of the Pyrenees, and estab-
lished the characteristic zones. A forest belt of Quercus
robur occurred on the lowermost slopes. This was bordered
by a zone of Fagus silvatica, and this in turn by Abies taxifolia,
and Taxus communis, which were replaced above by Pinus
silvestris and P. mugho. Above the forest ran a border of
thickets, consisting of Rhododendron, Daphne, Salix, etc., and
beyond these, reaching to the snow cap, lay a zone of herbs
and lichens, Gentiana, Primula, Saaxifraga, etc. Humboldt
and Bonpland ({805:37) employed the word region to designate
the zones of mountains, restricting zone to the vegetation
belts determined by latitude: they were not entirely consist-
ent in their use of these terms, however. The results of
their study of the vegetation of the Andes were graphically
represented upon a chart of Chimborazo and Cotopaxi, in
which were indicated the regions, the principal species of
each and the variations of temperature, pressure and
humidity. Schouw (1823:169) followed Humboldt and Bon-
pland in the use of zone and region, and further distinguished
the former as zones of latitude, and zones of longitude. A,
De Candolle (1855:248) discussed at length the question of
the upper and lower limits of mountain plants, first consid-
ering in a general way the influence of humidity, air and
soil temperatures, exposure, pressure, soil composition, ete. ,
and then in a more detailed manner the distribution of the

148 ZONATION

representative species. His conclusion was that tempera-
ture is the principal cause of zonation upon mountains, and
that dryness and insolation are secondary causes. Kabsch
(1855:303) distinguished twelve zones of vegetation, corres-
ponding exactly to the temperature zones of the earth, and
recognised eight regions in altitude, designatng them accord-
ing to the type of vegetation. Engler (1879:334) used the
term zone for the primary divisions of provinces: these do
not correspond to vegetation zones, but represent zonally
disposed regions or districts for the most part. Grisebach
(1872:129) established continental zones upon the busis of
dominant trees. Kéoppen (4884:215) laid down the principle
that the influence of temperature upon vegetation is best
measured by the length of the period in which the tempera-
ture lies between certain limits. On this basis, he proposed
the following zones: 1, tropical zone, temperature above
20° C. for all months; 2, subtropical zones, above 20° ©. for
4-11 months; 3, temperate zones, a, constantly temperate, b,
suramers hot, c, summers temperate, winters cold; 4, cold
zones, temperate for 1-4 months, the other months cold; 5,
polar zones, below 10° ©. for all months. Drude (1887:3)
characterised and charted the following zones of vegetation:
1, nordliche glacial zone; 2, nérdliche winterkalte zone; 8,
nérdliche sommerheisse zone; 4, tropen zone; 5, stidliche
sommerheisse und gemassigte zone; 6, siidliche kalte zone.

Raunkiaer (1889) noted the zonal arrangement of subform-
ations in the dune valleys of Jutland, where, in passing
from the dry margin of the valley to the moist center, the
following plants appear in zones: Calluna vulgaris, Erica
tetraliz, Myrica gale, and Aira uliginosa. Magnin (1893:241,303)
gave a new trend to the study of zones by his thorough
investigation of the zonation of the Jura lakes. He found
that the majority of these lakes regularly show the same
series of zones: 1, a litoral zone of amphibivus plants,
Phragmites, Scirpus; 2, an interior zone of floating plants,
Nuphar; 8, a central zone of floating or somewhat submerged
plants, Potamogeton; 4, a center of clear water, where Cera-
tophyllum, Naias, Chara, Nitella, etc., grow submerged.

HISTORICAL 149

Each zone was named from its facies, giving the series,
caricetum, phragmitetum, scirpetum, nupharetum, potamogetone-
tum, and charetum. He discussed the influence of the
general physical conditions of the lakes and of the structure
of the various species upon zonation, but in such general
terms that he was unable to give them definite expression.
MacMillan (1896:500) studied the zonation of the sphagnum
moors of Minnesota, and expressed his results in an impor-
tant generalisation. ‘‘It would seem that there are two
principal types of plant arrangement in their habitats.
These are: (1) Zonal and (2) Azonal. The first is connected
either with environmental conditions as a principal factor,
as in the case of the zonal distribution upon dome-shaped
islands, upon roches moutonnées, and on a larger scale upon
mountain peaks and isolated ranges, along lake or ocean
strand, and surrounding moors, or it may depend more
particularly upon the character and habits of life of the
plants themselves, as, for instance, in the case of the
“‘fairy-ring’’ fungus. The matter may be summed up ina
sentence. Generaliy, when there is well-marked radial symmetry
in the topographic feature upon which a group of plants is dis-
tributed, zonal arrangement is the response of the plant population
to these symmetric physiognomic conditions, but when the topo-
graphic feature is devoid of such well-marked radial symmetry
the plants dispose themselves according to the azonal type.
Talus-heaps, flat extended meadows, highly irregular hills,
shallow marshy ponds, and other such localities may serve
as illustrations of asymmetrical habitats. A variety of
conditions determines whether the distribution upon a given
area be zonal or azonal. And it is worthy of note that the
same formation may in one case arise by zonal, in another
by azonal distribution’. In a later paper, (1897:949), Mac-
Millan classified an extensive series of shore formations as
zonal and azonal, including in the latter talus, boulder, rock
and humus shores, in which there is often a mure or less
rudimentary zonation. Clements (1897:968) described the
lateral zones of subruderal plants, which border the old
trails of the Great Plains. Pound and Clements (1898:220)

150 ZONATION

pointed out that bilateral symmetry in the habitat was an
important cause of zonation, and insisted upon the funda-
mental nature of zonation, as a universal feature of vegeta-
tion. Clements (1902:b19) distinguished three types of
tepographical symmetry, viz., radial, bilateral, and unilat-
eral, to which correspond radial, bilateral and unilateral

zonation.

As the historical summary shows, the concept of zonation
is the oldest in phytogeography. Notwithstanding this, it
has never been clearly defined, nor has there been any
detailed investigation of the phenomenon itself, or of the
causes which produce it. Zones are so common, and often
so clearly marked, that they invite study, but no serious
attempt has heretofore been made to analyse zonation, or to
formulate a definite method of investigating it. Zonation
is the practically universai response of plants to the quanti-
tative distribution of physical factors in nature. In almost
all habitats, one or more of the physical factors present
decreases gradually in passing away from the point of great-
est intensity. The result is that the plants of the habitat
arrange themselves in belts about this point, their position
being determined by their relation to the factor concerned.
Close investigation will show that there is hardly a forma-
tion that is entirely without zonation, though in many cases
the zones are incomplete or obscure for various reasons.
Zonation is as characteristic of vegetation as a whole as it
is of its unit, the formation, a fact long ago recognised in
temperature zones. A continental climate, however, often
results in the interruption of these, with the consequence
that these belts of vegetation are not always continuous.

CAUSES OF ZONATION

The causes that produce zones are either biological, or
physical: the first have to do with some characteristic of
the plant, the second with the physical features of the
habitat. Biological causes arise from the method of growth,
from the manner of dissemination, or from the reaction of
the species upon the habitat. The formation of circles as a

CAUSES OF ZONATION 151

result of radial ¢rowth is a well-known occurrence with
certain plants, bui it is much more common than is supposed.
In the case of agarics, this phenomenon has long been
known under the name of ‘‘fairy-rings’’. It is found in a
large number of moulds, and is characteristic of early stages
of the mycelium of the powdery mildews. It occurs in
nearly all maculicole fungi, and is exhibited by certain
xylogenous fungi, such as Hysterographium. Among the
foliose lichens, it is a common occurrence with the rock
forms of Parmelia, Placodium, Physcia, and Lecanora, and with
the earth forms of Parmelia and Peltigera. The thalloid
liverworts show a similar’ radial growth. The flowering
plants, and many mosses also, furnish good examples of
this sort of growth in those species which simulate the
form of the mycelium or thallus. These are the species
that form mats, turfs, or carpets. Alpine mat formers,
such as Silene acaulis, Paronychia pulvinata, Arenaria
sajanesis, etc., are typical examples. Xerophytic, turf-form-
ing species of Muhlenbergia, Sporobolus, Bouteloua, Festuca,
Poa, and other grasses form striking ring-like mats, while
creeping species of Huphorbia, Portulaca, Amarantus, etc.,
produce circular areas. Rosettes, bunch-grasses, and many
ordinary rootstalk plants spread rapidly by runners and
rhizomes. The direction of growth is often indeterminate
in these also, and is in consequence more or less bilateral or
unilateral. Growth results in zonation only when the older
central portions of the individual or mass die away, leaving
an ever-widening belt of younger plauts or parts. This
phenomenon is doubtless due in part to the greater age of
the central portion, but seems to arise chiefly from the de-
mands made by the young and actively growing parts upon
the water of the soil. There may possibly be an exhaustion
of nutritive content, as in the case of the fungi, but this
seems improbable for the reason that young plants of the
same and other species thrive in these areas. It must not
be inferred that these miniature growth zones increase in
size until they pass into the zones of formations. Growth
contributes its share to the production of these, but there is

152 ZONATION

no genetic connection between a tiny plant zone, and a zone
of vegetation.

Radial, and bilateral growth play an important part in
formational zones in so far as they are related to migration.
The growth of the runner or rhizome itself is a very
effective means of dissemination, while the seeding of the
plants thus carried away from the central mass is most
effective at the edge of the newly occupied area. This
holds with equal force for plants with a mycelium or a
thallus. The circular area becomes larger year by year:
sooner or later, the younger, more vigorous, and more com-
pletely occupied circumference passes into a more or less
complete zone. This will result from the reaction of the
central individuals upon the habitat, so that they are readily
displaced by invaders, or from their increasing senility and
dying out, or from the invasion of forms which seed more
abundantly and successfully. This result will only be the
more marked if the radiating migrants reach a belt of
ground especially favorable to their ecesis. In this connec-
tion, it must be carefully noted that vegetation pressure,
before which weaker plants are generally supposed to flee,
or bv which they are thought to be forced out into less de-
sirable situations, is little more than a fanciful term for
radial growth and migration. It has been shown under in-
vasion that disseminules move into vegetation masses, as
well as away from them, the outward movement alone being
conspicuous, because it is only at the margin and beyond
that they find the necessary water, light and room for
growth.

Certain reactions of plants upon habitats produce zon-
ation. The zones of fungi are doubtless caused by the ex-
haustion of the organic matter present, while in lichens,
and mosses, the decrease in nutritive content has something
to do with the disappearance of the central mass. In the
mats of flowering plants, the connection is much less
certain. The reaction of a forest, or thicket, or even of a
tall herbaceous layer is an extremely important factor in the
production of zonation. The factor chiefly concerned here

CAUSES OF ZONATION 153

is light. Its intensity is greatest at the edge of the for-
mation, and just below the primary layer: the light becomes
increasingly diffuse toward the center of the forest, and
toward the ground. In response to this, both lateral and
vertical zones appear. The former are more or less in-
complete. and are only in part due to differences in illumin-
ation. The vertical zones or layers are characteristic of
forest and thickets, and are caused directly by differences
in light intensity.

The physical causes of zonation are by far the most im-
portant. They arise from differences in temperature,
water, and light. In the large, temperature differences are
the most important, producing the great zones of vege-
tation. In a particular region or habitat, variations of
water content and humidity are controlling, while light, as
shown above, is imporant in the reactions of forest and
thicket. Physical factors produce zonation in a habitat or
a series of habitats, when there is either a gradual and
cumulative, or an abrupt change in their intensity.
Gradual, slight changes are typical of single habitats,
abrupt, marked changes of a series of habitats. This modi-
fication of a decisive factor tends to operate in all directions
from the place of greatest intensity, producing a character-
istic symmetry of the habitat with reference to the factor
concerned. If the area of greatest amount is linear, the
shading-out will take place in two directions, and the sym-
metry will be bilateral, a condition well illustrated by
rivers. On the other hand. a central intense area will shade
out in all directions, giving rise to radial symmetry, as in
ponds, lakes, etc. The essential connection between these
is evident where a stream broadens into a lake, or the latter
is the source of a stream, where a mountain ridge breaks up
into isolated peaks, or where a peninsula or landspit is cut
into islands. The line that connects the points of accumu-
lated or abrupt change in the symmetry is a stress line or
ecotone (oixos, 6, habitat, révos, 6, stress). Hcotones are well-
marked between formations, particularly where the medium
changes: they are less distinct within formations. It is

154 ZONATION

obvicus that an ecotone separates two different series of
zones in the one case, and merely two distinct zones in the
other.

The physical symmetry of a habitat depends upon the dis-
tribution of water in it, and thisis profoundly affected by
the soil and the physiography. The influence of precipi-
tation is slight or lacking, as it is nearly uniform through-
out the habitat: the effects of wind and humidity are more
localised. Differences of soil rarely obtain within a single
habitat, though often occurring in a zoned series. The
strikingly zonal structure or arrangement of habitats is
nearly always due to differences in water content produced
by physiographic factors, slope, exposure, surface and
altitude. The effect of these upon water content and hu-
midity is obvious. Wherever appreciable physiographic
differences occur, there will be central areas of excess and
deficiency in water content, between which there is a
symmetrical modification of this factor. Peaks are typical
examples of areas oft deficiency, lakes and oceans of areas of
excess. When these areas are extreme and close to each
other, the resulting zonation will be marked; when they are
moderate, particularly if they are widely separated, the
zones produced are obscure. Asymmetry of a habitat or a
region practically does not exist. Central areas of excess
and deficiency may be very large and in consequence fail to
seem symmetrical, or the space between them so great that
the symmetry is not conspicuous, but they are everywhere
present, acting as foci for the intervening areas.

The response of vegetation to habitat is so intimate that
physiographic symmetry everywhere produces vegetational
symmetry, which finds its ready expression in plant zones.
The reaction of vegetation upon habitat causes biological
symmetry, typical of growth zones and light zones. From
these facts, it is clear that zonation will be regularly char-
acteristic of the vegetative covering. The zonal arrange-
ment of formations is usually very evident: the zones of a
formation are often obscured, or, where the latter occupies
a uniform central area of excess or deficiency, they are

KINDS OF ZONATION 155

rudimentary or Jacking, as in shallow ponds. Zones are
frequently imperfect, though rarely entirely absent, in new
soils, such as talus. They are rendered obscure in several
ways. In the initial stages of a succession, as well as in
the transitions between the various stages, the plant popu-
lation is so scattered, so transient, or so dense as to res-
pond not at all to a degree of symmetry which produces
marked zonation in later formations. The alternation of
conspicuous species not only causes great interruption of
zones, but often also completely conceals the zonation of
other species, such as the grasses, which though of more
importance in the formation, have a lower habit of growth.
Furthermore, the ecotones of one factor may run at right
angles to those of anuther, and the resulting series of zones
mutually obscure each other. Finally, such a physiogra-
phic feature as a hill may have its symmetry interrupted by
ridges or ravines, which deflect the zones downward or up-
ward, or cause them to disappear altogether, while the
shallows or depths of a pond or lake may have the same
effect. An entire absence of zones, i. e. azonation, is ex-
ceptional in vegetation. Almost all cases that seem to ex-
hibit it may be shown by careful examination to arise in
one of the several ways indicated above.

Two kinds of zonation are distinguished with reference to
the direction in which the controlling factor changes.
When this is horizontal, as with water content and tem-
perature, zonation will be lateral: when it is vertical, as in
the case of light, the zonation is vertical. There exists an
intimate connection between the two in forests, where the
secondary layer of small trees and shrubs is continuous with
a belt of trees and shrubs around the central nucleus, and
the lower layers of bushes and herbaceous plants with
similar zones still further out. This connection doubtless
arises from the fact that conditions are unfavorable to the
facies, outside of the nucleus as well as beneath it. Floris-
tically, each layer and its corresvonding zone are distinct,
as the one consists of shade, the other of sun species.
Lateral zonation is radial when the habitat or physiographie

156 ZONATION

feature is more or less circular in form, and it is bilateral,
when the latter is elengated or linear. Vertical zonation
is unilateral.

Radial zonation is regularly characteristic of elevations
and depressions. From the form of the earth, it reaches
its largest expression in the girdles of vegetation corres-
ponding to the zones of temperature. The zones of
mountain peaks are likewise due largely to temperature,
though humidity is a very important factor also. Mountain
zones are normally quite perfect. The zonation of islands,
hills, etc., is due to water content. In the former, the
zones are usually quite regular and complete; in the latter,
they are often incomplete or obscured. Prairies and
steppes are not zoned as units, but are complexes of more
or less zonal hills and ridges. Ponds, lakes and seas
regularly exhibit complete zones, except in those shallow
ponds where the depth is so slight that what is ordinarily a
marginal zone is able to extend over the entire bottom. The
line between an elevation and a depression, i. e., the edge
ot the water level, is the most sharply defined of all
ecotones. It separates two series of zones, each of which
constitutes a formation. One of these is regularly hydro-
phytic, the other is usually mesophytic. The line between
the two can rarely be drawn at the water’s edge, as this is
not a constant, owing to waves, tides, or periodical rise and
fall. There is in consequence a more or less variable trans-
ition zone of amphibious plants, which are, however, to be
referred to the hydrophytic formation. Nearly all forest
formations serve as a center about which are arranged
several somewhat complete zones. As arule, these merge
into a single heterugeneous zone of thickets.

Bilateral zonation differs from radial only in as much as it
deals with linear elevations and depressions instead of
circular ones. Wiih this difference, the zones of ranges and
ridges correspond exactly to those of peaks and hills, while
the same relation is evident between the zones of streams,
and of lakes and ponds. The ecotones are identical except
as to form: they are linear in the one, and circular in the

KINDS OF ZONATION 157

other. Incompleteness is more frequently found in bilateral
zonation, though this is a question of distance or extent,
rather than one of symmetry.

Vertical zonation is peculiar in that there is no primary
ecotone present, on either side of which zones arrange them-
selves with reference to the factor concerned. This arises
from the fact that the controlling factor is light, which im-
pinges upon the habitat in such manner as to shade out in
but one direction, i. e., downward. Vertical zones appear in
bodies of water, on account of the absorption of light by the
water. In a general way, it is possible to distinguish
bottom, plancton, and surface zones, consisting almost
wholly of algae. There is little question that minor zones
exist, especially in lakes and seas, but these await further
investigation. The must characteristic vertical zones occur
in forests, where the primary layer of trees acts as a screen.
The density of this screen determines the number of zones
found beneath it. In extreme cases the foliage is so deuse
that the light beneath is insufficient even for mosses and
lichens. As a rule, however. there will be one or more
zones present. Jn an ordinary deciduous forest, the layers
below the facies are five or six in number: (1) a secondary
layer of small trees and shrubs; (2) a tertiary layer of
bushes; (3) an upper herbaceous layer of tal! herbs; (4) a
middle herbaceous layer; (5) a lower herbaceous layer; (6) a
ground layer of mosses, lichens, other fungi and algae.
The upper layers are often discontinuous. the lower ones
‘are more and more continuous. As aforest becomes denser,
its layers disappear from the upper downward, the ground
layer always being the last to disappear because of its
ability to grow in very diffuse light. A vertically zoned
formation sbows a complex series of reactions. The pri-
mary layer determines the amount of heat, light, water,
wind, etc., for the subordinate layers in general. Hach of
these layers then further determines the amount for those
-below it, the ground layer being subject in some degree to
the control of every layer above it. This accounts probably
for the definiteness and permanence of this layer. The

158 ZONATION

degree to which the lower layers influence the upper by re-
acting upon the habitat is not known. It is evident that
this influence must be considerable by virtue of their con-
trol of the water supply in the upper soil strata, by virtue
of their transpiration, their decomposition, etc.

The ecotone between two formations is never a sharp line,
butit isan area of varying width. The edge of this area
which is contiguous to one formation marks the limit for
species of the other. Both formations disappear in this
transition zone, but in opposite directions. The over-
lapping which produces such zones arises from the fact that
the physical factors tend to approach each other at the line
of contact between formations, and that many species are
more or less adjustable to conditions not tco dissimilar.

As a fundamental expression of progressive change in the
amount of heat and water, zoaation is the most important
feature of vegetation. It constitutes the sole basis for the
division of continental as well as insular vegetation. The
continent of North America furnishes striking proof of the
truth of this. Conforming to the gradual decrease of
temperature and water content northward, three primary
belts of vegetation stretch across the continent from east to
west. These are forest, grassland, and polar desert. The
first is further divided into the secondary zones of broad-
leaved evergreen, deciduous, and needle-leaved forests. At
right angles to this temperature-water symmetry lies a
symmetry due to humidity alone, in accordance with which
forest belts touch the oceans, but give way in the interior to
grasslands, and these to deserts. It is at once evident that
the mutual interruption of these two series of zones has pro-
duced the primary features of North American vegetation,
i. e., tropical forests where heat and water are excessive,
deserts where either is unusually deficicnt, grassland when
one is low, the other moderate, and deciduous and conifer-
ous forests, where the water content is at least moderate,
and the temperature not too low. Such a simple yet funda-
mental division has been modified, however, by the disturb-
ing effect which three continental mountain systems have

CONTINENTAL ZONES 159:

had upon humidity, and upon temperature symmetry. The
two are intimately interwoven. The lowering of tempera-
ture due to altitude produces the precipitation of the wind-
borne moisture upon those slopes which look toward the
quarter from which the prevailing winds blow. A mountain
range thus makes an abrupt change in the symmetry, and
renders impossible the gradual change from forest to grass-
land and desert. The Appalachian system is not sufficiently
high to produce a pronounced effect, and forests extend far
beyond it into the interior before passing into prairies and
plains. On the other hand, the influence of the Rocky
mountains and the Sierra Nevada is very marked. The
latter rise to a great height relatively near the coast, and
condense upon their western slopes nearly all of the
moisture brought from the Pacific. The Rocky mountains
have the same effect upon the much drier winds that blow
from the east, and the two systems in consequence enclose a
parched desert. This series of major zones thus becomes,
starting at the east, forest, grassland, desert, and forest, in-
stead of the more symmetrical series, forest, grassland,
desert, grassland, forest, which would prevail were it not
for these barriers. This actual series of major zones under-
goes further interruption by the action of these mountain
systems in deflecting northern isotherms far to the south.
This action is greatest in the high ranges, the Rocky
mountains and the Sierras, and least in the lower Appala-
chians. Its result is to carry the polar deserts uf the north
far southward along the crests of the mountains, and to ex-
tend the boreal coniferous forests much further south along
their slopes. In the Appalachians, this means no more than
the extension of along tongue of conifers into the mass of
deciduous forests, and the occassional appearance of an iso-
lated peak. In the western ranges, it produces two svym-
metrical series of minor mountain zones, forest, alpine
grassland or desert, and forest, to say nothing of the foot-
hill and timber liue zones of thicket.

There seems to be no good reason for distinguishing the
zones of mountains as regions. The term itself is inappli-

160 ZONATION

cable, as it has no reference to zonation, and is used much
more frequently as a term of general application. Its use
tends to obscure also the essential identity of the so-called
vertical zones of mountains with the major continental
zones, an identity which can not be insisted upon too
strongly. For the sake of clearness, it is important to dis-
tinguish all belts of vegetation as zones, though it is evi-
dent that these are not all of the same rank. The following
division of the vegetation of North America is based upon
the fundamental principles of continental symmetry, and
the community of continental and mountain zones.
I. Polar-niveal zone—zona polari-nivalis
II. Arctic-alpine zone—zona arctici-alpina.

Arctic province—provincia arctica.

Alpine province—provincia alpina.
IIL. Boreal-subalpine zone—zona boreali-subalpina.

Alaska province—provincia alaskana.

Cordilleran province—provincia cordillerana.

Ontaria province—province ontariensis.
IV. Temperate zone—zona temperata.

Atlantic province—provincia atlantica.

Appalachian province—provincia appalachiana.

Nebraska province—provincia nebraskensis.

Utah province—provincia utahensis.

Coast province—provincia litoralis.

Pacific province—provincia pacifica.
V. Subtropical zone—zona subtropicalis.

Florida province—provincia fioridana.

Mexican province—provincia mexicana.
VI. Tropical zone—zona tropicalis.

Antilles province—provincia antilleana.

Andean province—provincia andeana.
“ The investigation of zones rests upon the instrumental
study of the factors of ecotones, and upon the quadrat ex-
amination of contiguous zones and of the transition area be-
tween them. As the methods are essentially the same as
for alternation, their detail will be found under the dis-
cussion of this principle.

1717

1751
1791
1801

1805

1813

1823

1836
~ 1855
1865

1874

1879

1883

1884

1887
1889

ZONATION 161

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Tournefort, J. P.
Linné, C. v.

Swartz, O.
Ramond, L. F. E.

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ZONATION

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163
ALTERNATION.

The term alternation is used to designate that phenom-
enon of vegetation, in which a formation recurs at different
places in a region, or a species at separate points in a for-
mation. Although it is afundamental feature of vegetation,
it has not been recognized heretofore, and has no history as
a concept. A degree of historical interest attaches, how-
ever, to one or two ideas that contain something of this
principle. Schouw (1823:68), in dealing with the geograph-
ical areas of species, distinguished them’as interrupted or
continuous, interrupted distribution containing, at least by
inference, some idea of alternation. In his concept of substi-
tution (221), Schouw has expressed a kind of alternation
found in related species or genera, which occur in different
regions. Meyen (1836:89) adopted the ideas of Schouw in
regard to interrupted areas, and definitised them in such a
way that interruption comes to be identical with the
simplest type of alternation, i. e., that in which a given
species recurs in separated but similar stations. A. De
Candolle (1855:472) spoke incidentally of sparse plants, which
“changent un peu de place, par une loi générale d’alter-
nance’, but he did not carry the idea further. In the
vicarious or representative forms of Drude (1890:124) and
others, there is a hint of this principle, but it was not
elaborated. Thornber (1901:55) discussed the general fea-
tures of the alternation of species in the prairie grass for-
mation. Jaccard (1901:547), in his statistical studies of
Alpine vegetation, has laid especial stress upon the floristic
diversity of different examples of the same formation. He
has sought to use this as an index of the physical character
of the habitat, however, and has not developed it further.

Alternation is the response of vegetation to the hetero-
geneity of the surface of the earth. It is in sharp contrast
to zouation in as muchas it is directly caused by asymmetry
in the topography. In consequence, it deals with the sub-
divisions of zones, arising from physical differences within
the symmetrical area. It deals with vegetation areas of

164 ALTERNATION

every rank below that of, major zone, with the habitat and
geographical areas of species, and in a certain way, with the
correspondence of vicarious genera. The breaking up of
vegetation into formations is a striking example of alter-
nation. The same phenomenon occurs in every formation,
producing associations and minor plant groups, and every-
where giving variation to its surface and structure. The
essential idea involved in this prixciple is the recurrence of
like formations, asscciations, or groups, which are more or
less separated by formations, associations, or groups differ-
ing from them. It is an exact expression of the primary
law of association that heterogeneity of structure varies
directly as the extent and complexity of the habitat, or the
series of habitats. Vegetation is made up of what are
superficially homogeneous formations, but upon analysis
these are seen to contain associations. The latter, though
more uniform than formations, break up into groups, each
of which still shows a characteristic heterogeneity arising
from the varying number and arrangement of its constituent
species,

The primary cause of alternation is physical asymmetry,
which is everywhere present within the symmetrical areas
which produce zoues. This is influenced so strongly, how-
ever, by migration and plant competition (phyteris') that
the consideration of this subject will gain in clearness, if
these are treated as separate causes. The essenital relation
between them must not be lost sight of however. Migration
carries disseminules into all, or only some of the different
areas of a formation, or into different formations, with little
respect to the physical nature of these. The physical char-
acter of these asymmetrical areas determines that some of
these plants shall be established in one series of places, and
some in another, while the competition between the indi-
viduals in the various areas determines the numerical value
of each species as well as its persistence. These three
causes are invariably present in the production of alternat-

1From the Greek: uréy, 76, plant; epts, ios, he competition.

CAUSES 165

ing areas, and originally, i. e., in new or denuded soils, the
sequence is constant, viz., migration, ecesis in asymmetrical
areas, and competition.

With respect to the different portions of an asymmetrical
area, migration will have one of three effects: (1) it will
carry disseminules into both favorable and unfavorable
areas: (2) into favorable ones only, or (3) into unfavorable
ones alone. From the radial nature of migration, the first
case is far the most frequent: it is typical of sporostrotes,
and the highly specialized spermatostrotes and carpostrotes.
The effect of migration is uniform here, and alternation
arises in consequence of the selective power of ecesis. It
is evident that migration does not have even an indirect
effect, when the disseminules are carried into none but un-
favorable situations. Where the movement is into favor-
able places alone, alternation is the immediate result. The
intermittent operation of migration, and the presence of
barriers are responsible for the absence of plants in situ-
ations favorable to them, and in consequence bring about a
certain alternation between corresponding species.

The selective operation of physical factors upon the dis-
seminules carried into the different parts of an asymmet-
rical area is the usual cause of alternation. Asymmetry
alone is universal within the more conspicuous structures
termed zones, down to the smallest areas which a group of
plants can occupy. The difference between contiguous
areas, particularly within the same habitat, is often small.
It sometimes seems inefficient in the initial stages of a suc-
cession when a single species is present, but even in
extreme cases its effect will be recognisable in the size and
density of the individuals. Asymmetry is clearly evident
in vegetation where two symmetrical series cross each
other, or when a symmetry is interrupted by barrier-like
elevations or depressions. Within formations, it arises
from differences, often very slight, in slope, exposure, ele-
vation, from irregularities of surface, differences in soil
structure, or composition, in the amount of cover, and in the

166 ALTERNATION

reactions of the living plants. At the last point, it isin
direct, connection with piant-competition.

Much uncertainty, as well as diversity of opinion, seems
still to exist in regard to the precise nature of the compe-
tition between plants that occupy the same area. It has
long been admitted that the phrase, ‘‘struggle for ex-
istence’’, is true cf this relation only in the most figurative
sense, but the feeling still prevails that, since plants live in
associations, there must be something mysterious and vital-
istic in their relation. Noone has been able to discover
anything of this nature, but nevertheless the impresssion
remains. Such a direct relation exists only between para-
sites, epiphytes and lianes, and the plants which serve to
nourish or support them. In the case of plants growing on
the same stratum, actual competition between plant and
plant does not occur. One individual can affect another
only in as much as it changes the physical factors that in-
fluence the latter. Competition is a question of the reaction
of a plant upon the physical factors which encompass it, and
of the effect of these modified factors upon the adjacent
plants. In the exact sense, two plants do not compete with
each other as long as the water content and nutrition, the
heat and light are in excess of the needs of both. The
moment, however, that the roots of one enter the area from
which the other draws its water supply, or the foliage of
one begins to overshade the leaves of the other, the reaction
of the former modifies unfavorably the factors controlling
the latter, and competition is at once initiated. The same
relation exists throughout the process: the stronger, taller,
the more branched, or the better rooted plant reacts upon
the habitat, and the latter immediately exerts an unfavor-
able effect upon the weaker, shorter, less branched or more
poorly rooted plant. This action of plant upon habitat and
of habitat upon plant is cumulative, however. An increase
in the leaf surface of a plant not merely reduces the amount
of light and heat available for the plant near it or beneath
it, but it also renders necessary the absorption of more
water and other nutritive material, and correspondingly de-

COMPETITION 167

creases the amount available. The inevitable result is that
the successful individual prospers more and more, while the
less successful one loses ground in the same degree. Asa
consequence, the latter disappears entirely, or it is handi-
capped to such an extent that it fails to produce seeds, or
these are reduced in number or vitality.

Competition in vegetation furnishes few instances as
simple as the above, but this will serve to make clear the
simplest case of ordinary competition, i. e., that in which
the individuals belong tu a single species. The various in-
dividuals of one species which grow together in a patch
shuw relatively slight differences, in height, width, leaf
expanse or root surface. Still, sume will have the largest
surfaces for the impact of water, heat and light. while
others will have the smallest: the majority, perhaps, will
occupy different places between the extremes. The former
will receive more than their share of one or more factors.
The reaction thus produced will operate upon the plants
subject to it inversely as the amount of surface impinged
upon. The usual expression of such competition is seen in
the great variation in height, branching, etc., of the
different individuals, and in the inability of many to pro-
duce flowers. This is particularly true of annuals, and of
perennials of the same generation. In the competition be-
tween parents and offspring of the same perennial species,
the former usually have so much the advantage that the
younger plants are often unable to thrive or even germin-
ate, and disappear, leaving a free space beneath and about
the stronger parents. This illustrates the primary law of
competition, viz., that this is closest when the individuals
are most similar. Similar individuals make nearly the
same demands upon the habitat, and adjust themselves least
readily to their mutual reactions. The more unlike plants
are, the greater the difference in their needs, and some are
able to adjust themselves to the reactions of others with
little or no disadvantage.

In accordance with the above principles, the competition
is closer between species of like form than between those

168 ALTERNATION

that are dissimilar. This similarity must be one of vege-
tation or habitat form, not one of systematic position. The
latter is in fact of no significance, except where there isa
certain correspondence between the two. Leaf, stem and
root characters determine the outcome, and those species
most alike in these features will be in close competition,
regardless of their taxonomic similarity or dissimilarity.
This is as conclusive of the competition between the species
of the same genus, as it is between those belonging to
genera of widely separated families. From this may be
deduced a second principle of competition viz., the closeness
of the competition between the individuals of different
species varies directly with their similarity in vegetation or
habitat form. This principle is of primary importance in
the competition which arises between occupants and in-
vaders in the different stages of succession. Those invad-
ing species that show the greatest resemblance to occupants
in leaf, stem and root form experience the greatest difficulty
in establishing themselves. The species, on the contrary,
which are so unlike the occupants that they come in at a
clear advantage or disadvantage, establish themselves
readily, in the one case as a result of the reaction, in the
other by taking a subordinate position. This principle lies
at the base of the changes in succession which give a
peculiar stamp to each stage. A reaction sufficient to bring
about the disappearance of one stage can be produced only
by the entrance of invaders so different in form as to
materially or entirely change the impress of the formation.
Stabilisation results when the entrance of invaders of such
form as to exert an efficient reaction is no longer possible.
qo forests, while many vegetation forms can still enter, none
of these produce a reaction sufficient to place the trees at a
disadvantage, and the ultimate forest stage, though it may
change in composition, can not be displaced by another.

it is obvious that the vegetation forms and habitat forms
of associated species are of fundamental importance in de-
termining the course and result of competition. Identity of
vegetation form regularly produces close competition, and

COMPETITION 169

the consequent numerical reduction or disappearance of one
or more species. Dissimilarity, on the other hand, tends
to eliminate competition, and to preserve the advantage of
the superior form. Species of trees compete sharply with
each other when found together: the same is true uf shrubs,
of rosettes, etc. The relation of the shrubs to the trees, or
of the rosettes to the shrubs of a formation is one of sub-
ordination rather than of competition. The matter of
height and width often enters here also to such a degree
that the tallest herbs compete with the bushes and shrubs,
and rosettes with mats or grasses. The amount and dispo-
sition of the leaf surface are decisive factors in the compe-
tition between species of the same vegetation form, in so far
as this is governed by light. In those plants in which the
leaves are usually erect, notably the grasses and sedges, the
competition between the aerial parts is relatively slight,
and the result is determined by the reactions of the under-
ground stems and roots.

The position of the competing individuals is of the
greatest importance. The distance between the plants
affects directly the degree of competition while their
arrangement, whether in groups according to species or
singly, exerts a marked influence by determining that the
contest shall be between like forms, or unlike forms,
Position is controlled primarily by the relation existing be-
tween seed-production and dissemination. It is of course
influenced in large measure by the initial position taken by
the invaders into a nudate area, but this is itself a result of
the same phenomena. The individuals of species with great
seed-production and little or no mobility usually occur in
dense stands. In these. the competition is fierce, for the
two reasons of similarity and density, and the result is that
the plants fall far below the normal in height and width.
This is an extreme example of the group arrangement.
When the seed-production is small, the mobility may be
great or little without seriously affecting the result. The
individuals of a species of this kind will be scattered among
those of other species, and the closeness of competition will

170 ALTERNATION

depend largely upon the similarity existing between the
two. The arrangement in such cases is sparse. A species
with great seed-production and great mobility usually shows
both kinds of arrangement, the position of the individuals,
and the competition between them varying accordingly.
This is due to the intermittent action of distributing agents,
making it possible for the seeds to fall directly to the
ground during the times that winds, etc., are absent. The
three types of arrangement indicated above are termed
gregarious, copious, and gregario-copious. They furnish
the basis for the investigation of abundance,’ which deals
essentially with the number and arrangement of the indi-
viduals of competing species. The effect of distance, i. e.,
the interval between individuals, upon competition is funda-
mental. The competition increases as the interval dimin-
ishes, and the reverse.

The view here advanced, i. e., that competition is purely
physical in nature, renders untenable the current concep-
tions of vegetation pressure, occupation, etc. Masses of
vegetation are thought to force the weaker species toward
the edge, thus initiating an outward or forward pressure.
As has been shown above, no such phenomenon occurs in
vegetation. This movement is nothing but simple migra-
tion, followed by ecesis, and has no counection with
‘‘weaker’’ species, or the development of a vital pressure.
The direction taken by the migrating disseminules is
essentially indeterminate. Migration seems to be outward,
or away from the mass, merely because the ecesis is greater
at the edge, where the increased dissimilarity between
plant forms diminishes the competition. The actual move-
ment is outward, but it takes place through the normal
operation of competition. In this connection, it should be
pointed out that the common view that plants require room
is inexact, if not erroneous. This is difficult of proof, as it
is impossible to distinguish room as such from the factors
normally present, light, heat, water and nutrient salts, but
it seems obvious that the available amounts of these will

1Pound and Clements. Phytogeography of Nebraska 2 ed. 59 1900

COMPETITION 171

determine the space occupied by a plant, irrespective of
the room adjacent plants may allow it. The explanation of.
competition upon physical grounds likewise invalidates the
view that plants possess spheres of influence, other than
the areas within which they exert a demonstrable reaction
upon the physical factors present.

Competition plays a very important role in alternation.
It produces minor examples of alternation in the physical
units of an asymmetrical series. Its greatest influence,
however, is exerted in modifying the effects of asymmetry.
The reaction of occupants emphasizes, or reduces the effect
of asymmetry, and has a corresponding action upon alter-
nation. This result of competition is typical of succession,
in which the sequence of stages arises from the interaction
of occupant and invader.

Alternation involves two ideas, viz., the alternation of
different species or formations with each other, and the
alternation of uhe same species or formation in similar but
separate situations. This is the evident result of asym-
metry, in response to which contiguous areas are dissimilar
and remvute ones often similar. Individuals of the same
species, or examples of the same formation may be said to
alternate between two or more similar situations, while
different species, or formations are said to alternate with
each other, occurring of course in situations different in
character. From the nature of alternation, the two phe-
nomena are invariably found together.

It is possible to distinguish three kinds of alternation: (1)
ofa formation, association, layer, facies or species in similar
situations; (2) of similar or corresponding formations,
species, etc., in similar situations; (3) of facies and other
species with respect to number. The last two are merely
variations of the first, arising out of slight differences in
the physical factors of the alternating areas, the adjacent
flora, or the course of competition. For this reason, they
are not sharply set off, and it is undesirable to distinguish
them by actualterms. Thealternation of different examples
of the same formation is a significant feature of greatly

172 ALTERNATION

diversified areas. such as mountains. It is naturally much
less characteristic of lands physiographically more uniform.
A xerophytic formation will alternate from ridge to ridge,
a mesophytic formation between the intermediate valleys:
aquatic vegetation will alternate from pond to pond, or
stream to stream. The appearance of new or denuded soils
upon which successions establish themselves is the most im-
portant cause of the alternation of formations. The
weathering of rocks in different areas of the same region
produces in each a sequence of similar or identical form-
ations. The same statement is true in general of other
causes of succession, such as erosion, flooding, burning,
cultivation, etc.. wherever they operate upon areas
physically similar and surrounded by the same type of
vegetation. The areascf more or Jess heterogeneous for-
mations characterized by major physical differences are
occupied by associations. In an extensive formation, the
same association alternates from one to another of these
areas that are similar. When the formation is interrupted
and occurs here and there in separate examples, an associ-
ation often alternates from one to another of these. An
association regularly derives its character from the fact that
one or more of the facies of the formation is more intimately
connected with certain areas of the latter than with others.
This explains why the alternation of associations and facies
are usuallv identical. Layers sometimes alternate between
different examples of the same forest or thicket formation,
when they are suppressed in some by the diffuseness of the
light.

The alternation of species is a typical feature of formations:
it is absent only in those rare cases where the latter consist
of a single species. The areas of a habitat which show
winor physical, or historical (i. e., competitive) differences
are occupied by groups of individuals belonging to one or
more species responsive to these differences. Each of these
groups will recur in all areas essentially similar, the in-
tervals being occupied of course by slightly different
groups. Such groups are constituted by gregarious or

KINDS 173

copious species of restricted adjustability. Sparse plants
likewise alternate, but they necessarily play a much less
conspicuous part. In habitats not too heterogeneous, a
large number of species are sufficiently adjustable to the
slight differences that they occur throughout the formation.
Often, to be sure, they show a characteristic response, ex-
pressed in the size or number. This is illustrated by the
facies and many of the principal species of the prairie for-
mation. Festuca, Koelera, Panicum, and Andropogon occur
throughout, except in the moist ravines which are prac-
tically meadows. Astragalus, Psoralea, Erigeron and Aster
grow everywhere on slopes and crests, but they are much
more abundant in certain situations. Other plants,
Lomatium, Meriolix, Anemone, Pentstemon, etc., recur in sim-
ilar or identical situations upon different hills. Lomatiwm
alternates between sandy or sandstone crests, Meriolix and
Pentstemon occur together upon dry upper slopes, while
Anemone alternates between dry slopes and crests.

Owing to the accidents of migration and competition,
similar areas within a habitat are not occupied by the same
species, or group of species. A species found in one area
will be replaced in another by a different one of the same,
ora different genus. The controlling factors of the area
render imperative an essential ideutity of vegetation and
habitat form, though in systematic position the plants may
be very diverse. Such genera and species may be termed
corresponding. The relation between such plants is essen-
tially alternation: it should, perhaps, be distinguished from
alternation proper as corresponsive. The prairie formation
furnishes a good example of this on exposed sandy crests,
upon which Lomatium, Comandra and Pentstemon alternate.
Formations exhibit a similar correspondence.

All species that alternate show a variation in abundance
from one area to another. Frequently, the difference is
slight, and may be ignored, except in determining abund-
ance. Very often, however, the variation is so great that a
facies may be reduced, numerically, to the rank of a prin-
cipal species, or one of the latter to a secondary species,

174 ALTERNATION

This phenomenon is distinguished as numerical alternation.
It arises from the fact that the similar areas are sufficiently
different to affect the abundance, without producing com-
plete suppression. It is probable that this result is due
almost entirely to competition. Astragalus crassicarpus
grows on all the slopes of the prairie formation, but on some
it has the abundance of a facies, while on others it is repre-
sented by a few scattered individuals This difference is
much more striking in separate examples of the same for-
mation, particularly when a normal facies is reduced to the
numerical value of a secondary species This is a matter of
great importance in the study of formations, for it has
doubtless often resulted in mistaking an association for a
formation.

Alternation furnishes the logical basis for what may be
called comparative phytogeography. The latter is of much
broader scope than the old subject of geographical distri-
bution, for it treats not only of the distribution of for-
mations and associations as well as of species, but it also
seeks to‘explain this by means of principles drawn from the
relation between habitat and vegetation. Jaccard (1901:547)
has given a fruitful trend to distributional studies. When.
the latter come to be fully based upon physical factor inves-
tigations, and upon the effects of migration and competition
as shown ‘in alternation, the comparative study of for-
mations will represent the highest type of phytogeographi-
cal*activity.

The investigation of the physical factors which produce
alternation concerns itself primarily with the conditions in
the nucleus of the alternating areas, except in those cases
where the areas are rather sharply delimited by an ecotone.
Here, as ‘elsewhere, the water content, and the physiogra-
phic factors which modify it, seem to be of greatest import-
ance, though’humidity doubtless has a more important effect
than is ordinarily ascribed to it. In layered formations,
light is of course the controlling factor. The influence of
migration is best determined by the use of the migration
circle described under invasion. The effects of competition

BIBLIOGRAPHY 175

and of the shifting brought about by physical changes from
year to year are measured and recorded by means of per-
manent quadrats, and quadrat photographs. These methods
are held to be indispensable to the scientific investigation
of alternation, as well as invasion, succession, and zonation.
The wealth of detail connected with the description, plaeing
and operation of physical factors instruments, with the form
of records and curves, and the application of the various
quadrat and photographic methods, has made it necessary
to refer these to another paper.

BIBLIOGRAPHY

1823 Schouw, J. P. Grundziige einer allgemeinen
Pflanzengeographie

1836 Meyen, F. J. F Grundrisz der Pfianzengeo-
graphie

1855 DeCandolle, A. Géographie Botanique Rais-
onnée

1874 Niageli, C. Verdingung der Pflanzenfor-

men durch ihre Mitbewer-
ber. Sitzungber. Akad.
Wiss. Miéinchen 3:205

1890 Drude, O. Handbuch der Pflanzengeo-
graphie
1901 Thornber, J. J. The Prairiegrass Formation

in Region I. Rep. Bot.
Surv. Nebr. 5:55

1901 Jaccard, P. Etude Comparative de la Dis-
tribution Florale dans une
portion des Alpes et du
Jura. Bull. Soc. Vaud.
87 :547