Botanical gazette.

i #2 i
z ;

i, XL No. re

THE
BoTANICAL GAZETTE

July, 1906

Editors: JOHN M. COULTER and CHARLES R. BARNES

CONTENTS
On Cretaceous Pityoxyla E. C. Jeffrey and M. A. Chrysler

A Study of the Vegetation of the Mesa Region East
of Pike’s Peak: the Bouteloua Formation H. L. Shantz

Contributions from the Rocky Mountain Herbarium.
Vil Aven Nelson

Briefer Articles
Anthoceros and its Nostoc Colonies Gevrge J. Peirce
Distribution and Habits of Some Common Oaks E. J. Hill

Current Literature

News

The University of Chicago Press
CHICAGO and NEW YORK
William Wesley and Son, Loudon

BOTANICAL GAZETTE

THE

BOTANIGAL GAZE [TE
- —_——cras

EDITORS:

JOHN MERLE COULTER anp CHARLES REID BARNES

VOLUME XLII

JULY— DECEMBER, 1906

WITH THIRTY PLATES AND NINETY-FIVE FIGURES

CHICAGO, ILLINOIS
PUBLISHED BY THE UNIVERSITY OF CHICAGO
1906

va & Pt. wel Gen

IsO7

PRINTED AT
The University of Chicago Press
CHICAGO

TABLE OF CONTENTS.

On Cretaceous Pityoxyla (with plates I and IT)
E. C. Jeffrey and M. A. Chrysler
A study of the vegetation of the mesa region east of
Pike’s Peak: The Bouteloua formation (with

map and thirteen figures) - - H. L. Shaniz 16,

Contributions from the re Movnisin aa
ium. Aven Nelson
The nascent forest of the Siiecni fcach sain goes
tributions to the ecological plant geography of
the Province of New Brunswick. No. 4 (wit
fourteen figures) - - - W. F. Ganong
The development and anatomy of Badavanis pur-
rea. Contributions from the Botanical Labora-
tory of the Johns Hopkins eae No. 5

(with plates IJI-V) -— - Forrest Shreve
On the importance of physiologically sees sn
tions for plants - W. J. V. Osterhout

The mG of the ie sictica Contributions
m the Hull Botanical Laboratory. L

Gwith seven figures) - _- - Heinrich Hasselbring

Differentiation of sex in thallus ee an
porophyte (with plate VI and three figures) Albert Francis Blakeslee

Cobmasiu as a is bari ited, aaa (with

one figure) - -
A new fungus of economic i. ra (with. thre

figures) Ralph E. ae Elizabeth H. Smith
The development a A ees a hee — six
ates - George F. Aikinven
Réle of seed coats in Silas germination, Contrl,

butions from the Hull Botanical meeouss

LXXXV (with four figures) William Crocker
Undescribed plants from Guateinas and othe Cen

CH. # wate,

tral American Republics. XXVIII - John Donnell Smith

g.) Trev. (with four figures) - - - Clayton O. Smith

tributions from the Hull Botanical Laboratory.
LXXXVI ioe nine ei and plates XIII-XV)
Charles J. Chamberlain

PAGE

I

179

48

81

107

127

—
ae
208
215

241

265

292

: 301

321

vi CONTENTS [VOLUME XLI

PAGE
Temperature and toxic action Mog pig -three
cha

rts - Charles Brooks 359
The Sab cies) ates some Cuban Nympacacese (with
plates XVI-XVIII) - - Melville Thiriton Cook 376

The life history of Polysiphonia iplicta. Contri-
utions from the Hull Botanical Laboratory.
LXXXVII (with three Hes and Lene XIX-

XXVIII) - - . + Shigeo Yamanouchi 401
The morphology of the ascocarp aa Se aT
in the many-spored asci of Thecotheus Pelletieri

(with plates XXIX and XXX) -. - - James Bertram Overton 45°
BRIEFER ARTICLES—

Anthoceros and its Nostoc colonies - - - George J. Peirce 55

Distribution and habits of some common oaks E. J, Hil 3

Nereocystis Luetkeana (with one figure) - - Theodore C. Frye 143

Two new species from Northwestern America - J.M. Greenman 146

CURRENT LITERATURE - . - - - 60, 148, 222, 311, 393, 493
For titles of books reviewed see index under |
author’s name and Reviews.
Papers noticed in “Notes for Students” are |
indexed under author’s name and subjects.
NEws - - - -

. e - 79; 160, 239, 319, 49°; 593

DATES OF PUBLICATION

No. 1, July 28; No. 2, August = No. 3, October 2; No. 4; October 233
No. 5, November 30; No. 6, Dec.

ERRATA

Vol. 41: p. 394, legend, for jig. 3, read fig. 4.

16, line 17, for 15°™ read 25°™.

17, line 1, for 15°™ read 25°™,

21, line 3, for 1889™ read 2000.

32, line 11, for (fig. 6) read (jig. 7).

66, line 20, for WEIS MAN read WEISMANN.

141, line 15, add Nov. 15.

164, line 11 from bottom, for concluding read including.

165, line 10, for dioecious read monoecious
308, line 10, for some read deeper colina:

308, line 20, for boullion read bouillon.

312, line 15, for ROBERTSON read ROBINSON.

oF FBS dW Of 20 BY Pe 1

SEEN ee ee nes

The Botanical Gazette

A Aontbly Fournal Embracing all Departments of Botanical Science

Edited by JOHN M. CouULTER and CHARLES R. BARNES, with the assistance of other members of the
botanical staff of the Uaiversiays of Chicago.

Vol. XLII, No. 1 : Issued July 28, 1906

5 CONTENTS

ON CRETACEOUS PITYOXYLA (wirH PLATES I AND m1). £.C. Jeffrey and M. A. Chrysler - I
A STUDY OF THE VEGETATION OF THE MESA REGION EAST OF PIKE’S PEAK:

E BOUTELOUA FORMATION (wirH Map AND SEVEN FIGURES). H.L. Shantz - 16
CONTRIBUTIONS FROM THE ROCKY MOUNTAIN HERBARIUM. VII. Aven Nelson 48
“BRIEFER ARTICLES.

NTHOCEROS AND ITS Nostoc CoLontes. George J. Peirce - =" . i 55
a DISTRIBUTION AND Hasirs oF SomME ComMMoN Oaks. E. J. Hill - - - - - 59
CURRENT LITERATURE.
BOOK REVIEWS - = ‘ ; = = ‘ S 60
EVOLUTION.

a CHEMISTRY OF PLANTS.
4 MINOR NOTIC = = : = 2

- - - - - . - - 62
; NOTES FOR eae - - - - - - . - - - ” 5 : 63
NEWS - it s ‘ i s : a 3 s e = E 79

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VOLUME XLII NUMBER 1

DOTANICAL = GAZETTE

FULY, 1906

ON CRETACEOUS PITYOXYLA.!
Le oe Jirrney AND M. A. CHRYSLER.
(WITH PLATES I AND II)

IN a recent publication Dr. ArrHur Ho.ttck? has described
the discovery of amber in the Raritan formation of the Middle
Cretaceous, at Kreischerville, Staten Island. The amber in ques-
tion occurs in largest quantity “in a stratum or bed, characterized
by layers and closely packed masses of vegetable débris, consisting
of leaves, twigs, and fragments of lignite and charred wood.” Lig-
nite occurring in association with amber at Cape Sable, Magothy
River, Anne Arundel County, Maryland, collected by Professor
A. Brpsrns of the Woman’s College, Baltimore, and of somewhat
similar geological horizon, has recently been determined by Dr. F.

- Kyowrron? of the United States Geological Survey as a new
species of Cupressinoxylon. It appeared desirable to one of us
that the lignites associated with the Kreischerville deposits of amber
should be subjected to microscopic examination, in view of the
possibility that the succiniferous ones might also turn out to belong
to an extinct species of Sequoia (Cupressinoxylon). On communi-
cating with Dr. Hotticx in regard to this possibility, he very kindly
consented to a combined visit to the beds at Kreischerville, for the
purpose of securing authentic specimens of the succiniferous and
other lignites. On April 18, 1905, we examined together the various

* Contributions from the Phanerogamic Laboratories of Harvard University, No. 5.

Amer. Nat. 39:137-145. 1905. Contributions from the New York Botanical
Garden, No. 64. -

3 American amber-producing tree. Science N. S. 3:582-584. figs. 1-4. 18096.

z

2 BOTANICAL GAZETTE [JULY

excavations in the Cretaceous clays at Kreischerville, particularly
that known as the Androvette pit, where the largest quantities of
amber have been found. We were fortunate enough on this occasion
to secure a large quantity of lignites, including several fragments
of some size, showing the amber in situ. On a subsequent visit,
in the following autumn a further supply of material was secured,
including some admirably preserved Pityoxylon from a newly opened
excavation known as the Drummond pit.

The lignites gathered at Kreischerville belong to at least three
genera: Araucarioxylon, Cupressinoxylon, and Pityoxylon. Of
these -only the last proved to be succiniferous. The first two
genera mentioned represent several species and present features
of very considerable interest, but it is not our intention to discuss
them further here. The pityoxyloid lignite containing masses of
amber was found in the form of large pieces from the various
excavations at Kreischerville, as well as in smaller fragments occur-
ring in the amber-bearing strata themselves, at the Androvette
pit, as described by Dr. HotticK (4. c.). The amber enclosed in
lignite appears both in the translucent shining condition and in the

dull ochraceous modification. In the latter state it is particularly —

conspicuous on account of the contrast in color with the black lignite,

and may be made out not only in the form of pockets and nuggets, —
but also as fine yellow threads or streaks corresponding to the normal —
resin passages of the wood. Unfortunately the state of preserva-
tion of most of the succiniferous lignites left something to be desired. — ,
In the Drummond and Androvette pits, however, were found a—
number of partially charred, and, as a consequence, exquisitely pre-_

served Pityoxyla, which were apparently specifically identical with

or at any rate closely allied to the actually succiniferous fragments —
of Pityoxylon. It has been thought advisable to defer the descrip-
tion of the amber-containing lignites until a greater quantity of
material should be accumulated, which might not only be better
preserved, but might also throw some light on the conditions leading —
to the formation of amber. The partially charred lignites belong-_

ing to the genus Pityoxylon Kraus appear, nevertheless, worthy
of immediate investigation, both because they show features of
considerable phylogenetic interest, and because the genus Pity- ;

i

1906 | JEFFREY & CHRYSLER—CRETACEOUS PITYOXYLA 3

oxylon is considered by some paleobotanists not to antedate the
Tertiary.4

The specimens of Pityoxylon, which have served as the material
for the present investigation, consist for the most paft of cylindrical
fragments, which are sometimes as thick as 10°™ and often twice
as long. Most of them however are of smaller size. Where the
pieces are cylindrical they generally include the pith in a good state
of preservation, a feature of some importance in connection with
their diagnosis. It is not possible to state absolutely from the nature
of the specimens whether they represent smaller branches or merely
the core of larger axes from which the external layers have been
burned off. From the ordinarily tylosed condition of the resin
canals, it may be inferred with a strong degree of probability that
the latter supposition is more likely to be correct. Angular frag-
ments showing annual rings with a large radius of curvature permit
a study of the structure of the older wood. Although at least two
different species of fascicles of pine needles and at least as many
species of cone scales of Pinus, all in an admirable condition of
preservation, have been found in association with the Pityoxyla
from the Androvette pit, it has not been possible to distinguish in
these lignites more than one type of wood structure. The material
in this respect presents an interesting parallel to the condition found
by CONWENTZS to exist in the Pityoxyla of the Eocene or early Oligo-
cene, which bear the well-known Baltic amber; for this author
declares that he is unable in the vast variety of fossil succiniferous
woods which have passed under his inspection to diagnose more

than a single species. The absence of clearly marked criteria for

the separation of species on the basis of wood structure is not sur-
prising, since even in the case of living pines it is difficult to do more
than segregate the various species into larger groups or sections
on the characters offered by the wood.

Fig. 1 shows the structural features of a transverse section of
a slightly flattened branch about 5°™ in thickness in its greatest
diameter, and showing more or less distinctly about twenty annual

4Cj. GoTHAN, Zur Anatomie lebender u. fossiler Gymnospermen-Hélzer 88,
Herausgeb. von der Kéniglich Preussischen pcologischen Landesanstalt. und
B ie. pp. 108. Berlin, r905.

5 Monographie der Baltischen Bernsteinbiume. Danzig, 1890.

4 BOTANICAL GAZETTE [yury

rings. It is to be observed from the photograph that the annual
rings are not as strongly marked as they are in pines of the present
day. This feature is due to the less pronounced thickening of the
tracheids of the summer wood. There are no parenchyma cells
present in the wood except those which surround the resin canals.
The rays are strongly marked on account of the resinous character
of their contents, a feature of difference from modern pines, where
as a rule the ray-cells are quite free from the dark brown secretion
which is characteristic of the resiniferous cells in the Cupressineae
and in the genera Cedrus and Tsuga among the Abietineae. The
resin canals show a tendency to become aggregated in clusters. They
may be almost absent in one or more annual rings and correspond-
ingly abundant in others. The resin ducts are surrounded by highly
resiniferous cells and appear not to be confined to any special region
of the annual ring. On the left of the figure is to be seen a resin
canal occluded by tyloses.

Fig. 2 shows a section of the same branch which includes a portion
of the pith. The medullary cells are filled with dark brown contents.
Sclerified cells are quite absent in the pith. To the right of .the
photograph a process passes off from the medulla, which is the pith
of a small branch, in all probability a brachyblast or short shoot.
In the wood immediately adjoining the pith may be seen a number >
of resin canals, closely filled with tyloses. The position of these —
resin canals in relation to the pith is that found among living species
of Pinus, in the hard pines (Scleropitys auct.), in which the resin
canals also abut on the pith, in some cases actually occurring in
the primary wood, in contrast to the soft pines (Malacopitys auct.),
where the resin ducts are somewhat remote from the pith and never
occur in the primary wood. The annual rings are generally less”
well marked in proximity to the medulla than in the more external
part of the wood.

Fig. 3 is a longitudinal radial view of the wood of the same speci-
men illustrated in the two preceding photographs. The section
shows a single vertical and several anastomosing horizontal resin
canals, all quite filled with tyloses. A careful inspection indicates
that the wood is made up of tracheids, which are provided with
a single vertical row of radial bordered pits. :

i i

1906] JEFFREY & CHRYSLER—CRETACEOUS PITVOXYLA 5

Fig. 4 shows the structure of the wood in the same specimen,
as seen in tangential section under a low magnification. The rays
are of the two kinds found in Pityoxylon Kraus, namely, linear and
fusiform.

Fig. 5 shows a tangential view of part of the same section, more
highly magnified. In this view the radial pits of the tracheids may
be seen in profile, and on the left a face view of a few tangential
pits. In some of the rays dark contents may be made out in the
cells, which have partially shrunk away from walls. This is appar-
ently of the same nature as the dark brown material found in the
resin cells of certain living conifers. The interesting fact to be
noted is that the resin occurs equally in the marginal and in the
central cells of the ray. This feature may be clearly distinguished
in two of the rays on the lower left portion of the photograph. In

living pines resin never occurs in the marginal cells of the ray, which,

as is well known, are not true parenchymatous cells, but are of a
tracheary nature. They are in fact variously described as mar-

ginal tracheids, horizontal tracheids, and tracheidal cells.

Fig. 6 shows another portion of the same section as that repre-
sented in fig. 4, on the same scale of magnification as jig. 5. This
figure shows very clearly the occurrence of tangential pits, which

are confined to the autumnal tracheids as in certain living species
of Pinus. In jigs. 5 and 6 may be seen fusiform rays containing

horizontal resin canals occluded by tyloses.
Fig. 7 represents a transverse section, under high power of mag-
nification, of the autumnal wood of a specimen showing annual

rings with a large radius of curvature. The elements are much

larger in this instance, as is the rule in the older wood of the Conif-
erales in general. The tangential pits of the autumnal wood can
be very clearly made out. We have found no specimen of Pity-
oxylon from the Kreischerville deposits in which the tangential

‘pitting of the autumnal tracheids is not a marked feature. Con-

WENTZ has pointed out that this feature is also present in the autumnal
wood of the Baltic amber-producing trees (/..¢., p. 21).

It will be inferred from the above description that the Cretaceous
Pityoxyla just described differ in several features from the woods

.of any modern or even Tertiary species of Pinus. The leafy short-

6 BOTANICAL GAZETTE [JULY

shoots found in intimate association with the Pityoxylon here de-
scribed, which unquestionably belong to the genus Pinus in the
narrower sense, have the double bundle which is characteristic
of the hard pines,® as has been learned by one of us from a micro-
scopic investigation of their structure. They are also provided
with the persistent foliar sheaths, which are a striking feature of
the hard or pitch pines in contrast to the soft pines, which have
deciduous sheaths. All the numerous cone scales found in intimate
association with the wood, illustrated in our figs. 1-7, are equally
characteristic of the hard pines, for they have the thickened apophy-
sis and median umbo, which are unfailing features of that group.
In the case of our Pityoxylon, however, we find universally present
the tangential pits of the autumnal tracheids, which are character-
istic of the existing soft pines.7 STRASBURGER, however, states
that he has found tangential pits to be present in the autumnal
wood of Pinus canariensis and Pinus rigida. Mayr® has also
called attention to the occasional occurrence of tangential pits in
the autumnal wood of one group of the hard pines. This feature
has also not escaped the notice of CoNnWENTz. One of us has
observed the very frequent occurrence of tangential pits in the —
autumnal wood of the cone in various species of hard pines, where —
they are quite absent in the vegetative wood. This is the case, for —
example, in the woody axis of the cone of P. Pinaster, the vegeta~ _
tive wood of which is described by Kraus? as having no tangential |
pits. P. palustris too, although it is a characteristic hard pine, in the
absence of tangential pits from its autumnal wood,*° possesses these —
in great abundance in the.autumnal wood of its cone, in both the |
annual rings present. These two examples will suffice to illustrate —
the fact that tangential autumnal pits, such as are ordinarily absent —
in the wood of hard pines, are generally. present in their cones. It |
may be inferred from the mode of their occurrence that tangential
~ 6 Coutrer and Rose, Synopsis of North American pines based on leaf-anatomy- |
Bot. Gazetre T1:256, 302. 1886.

7 OW, Anatomy of the Coniferales. Amer. Nat. 38:243. 1904. STRAS~
BURGER, Ueber den Bau und die Verrichtungen der Leitungsbahnen in den Pflanzen. —

. Nordamerikas.
° Beitrage zur Kenntniss fossiler Hélzer,

p- 25.
© PENHALLOW, Joc, cit., 204.

1906] JEFFREY & CHRYSLER—CRETACEOUS PITYOXYLA 7

bordered pits in the tracheids of the hard pines are an ancestral
feature. It is accordingly not surprising to find them more com-
monly present in older types of hard pines than those now living.
CONWENTZ in his admirably accurate and thorough account of the
wood of Pinus succinifera notes their invariable presence in this
species, which on account of its denticulate marginal ray-tracheids
must be considered to belong to the hard pines. As has already been
pointed out, the structure of the associated leaf fascicles and cone
scales leads to the conclusion that the Cretaceous Pityoxylon under
discussion belongs also to a hard pine. The mode of occurrence of
the resin canals in the medullary crown, which is illustrated in jig.
2, is also that which is characteristic of the hard pines.

The most reliable feature of difference separating histologically
the hard pines from the soft pines is the occurrence of denticulate
marginal tracheids in the former group. In the soft pines the mar-
ginal tracheids are entirely without denticulations. In our Pity-
oxylon, as has been shown above, marginal tracheids of any kind
are quite absent; so that it is not possible on this feature to diagnose
the affinity of our material with either of the two main groups of
pines still living. It is of interest to note that the Cretaceous Pity-
oxylon under discussion has the general structure of the rays found
in Abies or Pseudolarix, with the wood structure found in Tertiary
and modern species of Pinus. There can be little doubt that in the
peculiar structure of the rays we have to do with an ancestral feature;
for if we take for example a modern species of Pinus, in which the
marginal tracheids are well developed even in the first annual ring,
such as P. palustris, we find the marginal tracheary cells entirely
absent in most of the rays of the two annual rings of the female
cone. It is well known that in many of the modern species of Pinus
the marginal tracheary ray-cells do not appear until the branch
is from one to several years old. The same feature, if one may
judge from CoNweENtTz’ description, was also present to an even
more marked degree in the Baltic amber pines, which are considered
by CoNnWENTz to belong to the early Oligocene or late Eocene.
Another feature of striking resemblance presented by the wood
of the cones only of existing species of Pinus, to the vegetative woods
of Cretaceous Pityoxyla which we have investigated, is the highly

8 BOTANICAL GAZETTE [yULY

resinous character of the ray-cells. This feature may also be well
seen in P. palusiris, already referred to. The contrast in the con-
tents of the ray-cells as they occur in the wood of the cone or of a
vegetative branch is very strongly marked.

It may be inferred that we have overlooked the presence of
tracheary marginal cells in the Cretaceous Pityoxyla, which are
the subject of the present article. This view cannot however be
accepted, as the wood of some of our partially charred specimens
is in a perfect condition of preservation, often not even showing
the spiral striations which are generally found as a feature of deca
in many fossil woods, otherwise well preserved. Moreover, in
shallow rays consisting of a single stratum of cells, which in the
case of modern species of Pinus are composed entirely of tracheids,
the cells are parenchymatous and invariably filled with a dark brown
resinous content, which leaves no doubt as to their histological
nature. The cells on the margins of the rays in our Pityoxylon

are moreover related to the central cells of the rays and to each ©

other by simple pits and not by bordered pits, as is the case with
the marginal tracheids. It is obvious that the ray-structure of
Pinus underwent a great change in the passage from the Mesozoic
to the Tertiary period.

On account of the geographical occurrence of the Pityoxylon,
which has just been described, it is called Pityoxylon statenense.
The diagnosis is as follows:

Transverse —Annual rings narrow, sometimes not clearly marked; wood _
parenchyma absent except in the periphery of the resin canals, which may occur ~

in any part of the annual rings and are often stopped with tyloses; rays highly

resinous; bordered pits present on the tangential walls of the autumnal tracheids; :

tracheids about 25 « in diameter.

Radial.—Radial pits of tracheids about 17 u in diameter, in a single vertical
row, round with a round mouth; pits of the ray-cells about one per tracheid,
round or somewhat elliptical, ro # in diameter; ray-cells all parenchymatous,
very resinous, length from 100 to 120 #; marginal ray tracheids quite absent.

Tangential—Rays of two kinds, linear and fusiform, the latter containing
resin canals which are surrounded with rather thick-walled parenchyma; resin
canals often occluded by tyloses; tangential pits present in the autumn wood.

In addition to the Pityoxylon described above, we have examined

another of the same type, which was secured by Dr, Isaac BowMAN. 3

*

1906] JEFFREY & CHRYSLER—CRETACEOUS PITYOXYLA 9

from a newly exposed section at Third Cliff, Scituate, Mass. Al-
though there is some question as to the exact geological age of the
strata from which it was taken, it is considered desirable to refer
to it at the present time on account of the interesting similarity to
the species discussed above. Dr. Bowman describes‘? the section
from which the material was taken as follows: “The section at Third
Cliff shows yellow clays at the base conformably overlain by yellow
and white sands and succeeded by a bed of bright red sands with
an unconformity at their base. On the eroded edges of the red
and white beds are deposited dark glauconitic and lignitic clays and
sands. The entire series of beds has a total maximum thickness
of 60 or 70 feet and outcrops for half a mile along the cliff face.
Absolutely no erratic material occurs either within the beds them-
selves or along the lines of unconformity.’’ The lignite to be de-
scribed came from the ‘“‘lignitic sands and clays” just mentioned.
The material consisted originally of several laminated and badly
preserved fragments, together with one larger piece, cubical and
about 12°™ in its three dimensions. The better-preserved fragment
has served as the basis of the following description. As the result
of decay and pressure, the lignite has suffered some compression
both in the radial and tangential planes. The stress in the radial
plane has produced a considerable sinuosity in the course of the
wood rays. The annual rings cannot be made out with the naked
eye or even with a pocket lens of some degree of magnification.
Fig. 8 shows a magnified portion of a transverse section of this
wood. The area of the photograph includes parts of two annual
rings. The line of demarcation is very indistinct and runs obliquely
a little above the lower third of the photograph. The rays are very
dark on account of the highly resinous character of their contents.
Two large patches of parenchyma may be seen surrounding two
vertical resin canals. The large amount of resiniferous parenchyma
about the canals is particularly characteristic of this species. There
are no parenchyma cells in the wood other than those surrounding
the resin canals. The annual rings have a very slight radius of
curvature and are somewhat distorted on account of the compression
of the wood, although the elements which compose them are well
11 Science N. S. 22:993-994. 1905.

ite) BOTANICAL GAZETTE [JULY

preserved. The lignite under discussion obviously is part of an
old stem.

Fig. 9 is a radial view of the wood of the Pityoxylon from the
cliffs at Scituate. This view shows the extremely resinous char-
acter of the rays, which doubtless is largely responsible for the good
preservation of the wood, as, unlike the material of Pityoxylon staten-
ense, it has not been charred in any way by fire. The rays are
quite without tracheidal marginal cells and in this respect resemble
those of the first described species, and differ from the ray vege-
tative structure found in any modern species of Pinus.

Fig. 10 shows a tangential view of the wood. The rays are
obviously of two kinds, namely, linear and fusiform. The former
are often very deep, and in this feature present a marked contrast
to the first described species of Pityoxylon. The fusiform rays
are usually occupied by a horizontal resin canal, the lumen of which
is often filled with a dark brown material similar to that found in
the surrounding resiniferous cells of the ray. Tyloses have not been
found either in the horizontal or the vertical resin canals of this species.

Fig. 11 shows a portion of the same section more highly magni-

fied. The highly resinous character of the rays can clearly be made
out. There is one fusiform ray present containing a horizontal —
resin canal, which is filled with a dark brown material similar to |
that found in the ray-cells. It may here be stated that in spite of —

the fact that the cells surrounding the lumina of the horizontal and
vertical resin ducts cannot be descri

walled, nevertheless the ducts are never occupied by tyloses.

Fig. 12 shows another tangential view under considerable magni- :

e fact that in the rays the marginal as
tain the same dark brown resin, as has
the case of the other Cretaceous Pity- :
The wood is so well preserved that there —
can be no question as to the absence of marginal tracheids, such —

fication. This illustrates th
well as the central cells con
already been referred to in
oxylon described above.

as occur in the rays of living species of Pinus and allied genera.
Not only are the marginal cells filled with the same dark resinous
material as the other cells of the tay, but they are related radially

to each other, as well as to the central cells of the ray, above and
below by simple pits. 7

bed accurately as being thick- —

1906] JEFFREY & CHRYSLER~—CRETACEOUS PITYOXYLA Il

This species of Pityoxylon is named Pityoxylon scituatense, from
its place of origin. The diagnosis is as follows:

Transverse.—Annual rings moderately broad, indistinctly marked; resin
ducts present, surrounded by a very deep zone of resiniferous parenchyma,
without tyloses but sometimes filled with dark resinous contents; wood paren-
chyma quite absent; rays very dark and resinous; tracheids averaging 39 u
in diameter.

Radial.—Radial pits of the tracheids in a single row with the very oblique
narrow mouths forming a cross, diameter of the pits about 20 4; pits of the ray-
cells generally one per tracheid with narrow oblique mouth, about ro # in diam-
eter; ray-cells all parenchymatous, average length 340 #, very resinous; marginal
ray-tracheids quite absent.

Tangential.—Rays of two kinds, linear and fusiform, the former often very
deep; fusiform rays containing horizontal resin canals, which are always free
from tyloses although somewhat thin-walled, both kinds of rays very resinous;
tangential pits present in some of the tracheids.

In the two species of Pityoxylon described above, we have to
do with woods which resemble those of the existing pines, but which
nevertheless differ from them in important particulars. The mar-
ginal ray tracheids, which are not only characteristic of Pinus but
of the allied genera Picea, Pseudotsuga, and Larix, are quite absent
in our two species. The question arises whether it is proper to
include them within the genus Pityoxylon, which has recently been
stated not to antedate the Tertiary.‘? There is much to be said
for such a course. In the case of our Pityoxylon statenense there
can be no reasonable doubt that we have to do with the wood
of a fossil species of Pinus, from the abundant occurrence in
intimate association with the lignites of charred remains of cone
scales and leaf fascicles of pines. Any doubt as to the identity of
these scales and foliar shoots has been removed by a study of their
microscopic structure, as well as their external features. Further,
one of us has observed from the study of the cones of living pines
that the features which are characteristic of our fossil woods are
exactly those which are found to be distinctive of the wood struc-
ture of the cones of the living species of Pinus. There can be little
doubt that in the case of the wood of the cones of Pinus palustris,
for example, the general absence of marginal tracheids, the highly
resinous character of the rays, and the abundant presence of tan-

12 GOTHAN, /. ¢., pe 88.

12 BOTANICAL GAZETTE [JULY

: gential autumnal pits, all features of difference from the vegetative
wood structure of existing hard pines, are ancestral characters,
since such characters are wont to linger on in the reproductive axis.
Indeed in no other way can the presence of these features in the wood

=

of the cone be explained. It seems inadvisable to invent a new _

generic name for a fossil wood, which although lacking the marginal
ray tracheids, which are characteristic not only of the wood of living
pines, but of also Pityoxylon as generally defined, is beyond any
reasonable doubt the wood of a Cretaceous pine. We find it diffi-
cult to follow Gorwan (I. c., p. 102) in establishing a new pityoxyloid
genus of fossil woods, Pinuxylon, to which is assigned the ligneous
characters of the living Pinus in the narrower sense. Pityoxylon
Kraus seems rather in need of a wider than a narrower interpre-
tation, if it is to include the wood of Pinus of the Cretaceous as well
as Tertiary times. In the case of our Pityoxylon statenense there
can be no reasonable doubt that we have to do with the wocd of
an extinct Cretaceous pine. It seems on account of its distinctive
archaic features, however, inadvisable to name it under Pinus as
ConwEN7z has rightly done in the case of the Tertiary Pinus suc-

cinijera, which jis practically identical in its wood structure with —
modern hard pines. The retention of the genus Pityoxylon Kraus —

appears, for the present at any rate, absolutely essential in view of
such cases as that presented by our Pityoxylon statenense. The

evidence as to Pityoxylon scituatense is much less clear, as no cone
scales or leaves have been found with it. Since, however, it presents —

the same general features as P. statenense, it may conveniently be
included under the same genus.

There is good reason to believe from recent researches"? that
the genus Pinus in essentially its modern form, so far as the external

features of the female cones go, existed as far back as the Jurassic.
There is even evidence that the two great series of the hard and
soft pines existed at this early period so that the geological extension
of the genus must have been much more remcte. Without con-
sidering the evidence for the existence of Abietineae at earlier geo-

logical periods than the Tertiary, furnished by impressions of the a
13 FLicHe, P. et ZEILLER, R., Florule portlandienne des environs de Boulogne- q

sur-Mer. Bull. Soc. Géol. France IV. 4:787-812. 1904.

et ie AR 2 saps papempeeatene iene.
RE Sen ee pe tf te ee 7 CPE abe Wie DE Taart Bit aati gt Te re oes

Ee
eer rer ere

1906] JEFFREY & CHRYSLER—CRETACEOUS PITYOXYLA 13

foliage, etc., there are now definite records, based on internal struc-
ture, which carry the group far into the past. KNowLron™ has
recently described an abietineous wood from the Jurassic beds of
the Black Hills of Dakota which he calls Pinoxylon dacotense. It is
characterized by the possession of vertical resin canals only, which
are numerous and may occur in any part of the clearly marked annual
rings. The structure of the tracheids and rays is that of the Abiet-
ineae. This author does not mention the presence of marginal ray
tracheids, and in view of the fact that he describes the wood as
admirably preserved, they probably may be considered to be absent
here as in our Cretaceous Pityoxvla.

The Pityoxylon Conwenizianum of GoEPPERT from the ee
boniferous of Waldenburg,'5 which has often been called in question,
has received full confirmation from the description of a similar
type of Pityoxylon, P. chasense, by PENHALLOw'® from the Per-
mian of Kansas. In these two species vertical resin canals are
said to be absent, although the horizontal canals of the fusiform
rays are clearly present. There is, accordingly, every reason to
believe that the Abietineae are a very ancient group in their first
appearance. In fact, they may be traced geologically quite as far
back as the Araucarineae, which it is customary at the present time
to regard as the oldest of the Coniferales. That they are not more
‘numerously represented in the Mesozoic and earlier strata is probably
entirely a matter of antisepsis, since araucarineous remains are
in general much better preserved than are those of the Abietineae,
where they are found imbedded together in the same strata. Men-
tion need not be made here of the Pityoxylon eggense (Witham)
Kraus and Pityoxylon Hollicki Knowlton,*’? since both of these
appear to have been in a bad state of preservation.

The peculiar structure of the wood of Pinus in the Go cconus,
as distinguished from that found in the case of Tertiary and living
pines, probably affords an explanation of the greater vigor of the

14 U. S. Geol. Surv. Ann. Rept. 207: 420-422. 1898-1899.

15 GOEPPERT, Revision meiner Arbeiten.

r6 North American species of Dadoxylon. Trans. Roy. Soc. Canada II. 64:76.
1900.

17 Trans. N. Y. Acad. Sci. 16:134-136.

14 hoes BOTANICAL GAZETTE [JULY

genus ‘under modern conditions. It is generally inferred that genera
which flourish under modern conditions cannot be of very ancient
origin: This generalization, however, cannot be accepted in
the case of Pinus, which, although found actually abundantly
throughout the northern hemisphere in from 80 to gO species, can
be traced in obviously allied genera back to the Carboniferous.

The appearance of marginal ray tracheids about the beginning of —

the Tertiary epoch, with the resulting improvement of water-supply,
in all probability explains why so comparatively large-leaved a conifer
should have been able not only to live on into the modern period,
but to flourish as it never had before. Even at the comparatively
early epoch of the Baltic amber beds (probably Eocene), there were
numerous species present in the somewhat restricted area repre-
sented by that formation.

CONCLUSIONS.

1. The woods of certain pines of the Middle Cretaceous of Staten
Island differed from those of existing pines (a) in the absence of
marginal tracheids in the rays; (6) in the highly resinous nature
of the rays; (c) in the association of characteristic features of the

hard pines, as exemplified by leaf-fascicles, cone-scales, and struc-
ture of the primary wood, with the numerous tangential pits of the —

autumnal wood which are a feature of the living soft pines.
2. These features of difference from modern pines are probably

GP ete AEA DST oo eee ee ee

= esa

- ~ STeie,

to be regarded as ancestral, since they persist clearly and strongly in :

the structure of the wood of the cones of the living species.

3. The appearance of marginal tracheids in the rays of Pinus ©

is comparatively modern and does not in all probability antedate —

the Tertiary. It. probably explains the greater prosperity of the 3

genus in recent times.
4. Another species of Pityoxylon from Scituate, Mass., has

been described, which has the general features of the Pityoxyla of |

Staten Island... It is not possible, however, to refer it definitely te.
Pinus, nor is its geological horizon settled. .
In conclusion we Wish to offer our warm thanks to Dr. HoLLick i

for many kindnegses in the matter of securing material.

HARVARD UNIVERSIry.

BOTANICAL GAZETTE, XLII PLATE I

To replace Plate I, inverted in July number.

PEAT EAL

BOTANICAL GAZETTE, XLII

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JEFFREY & CHRYSLER on PITYOXYLA

BOTANICAL GAZETTE, XLII

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JEFFREY & CHRYSLER on PITYOXYLA

PLATE I

BOTANICAL GAZETTE, XLII PLATE TI

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JEFFREY & CHRYSLER on PITYOXYLA

1906]

JEFFREY & CHRYSLER—CRETACEOUS PITYOXYLA

ARP WP H

EXPLANATION OF PLATES I AND IL.
PLATE I.

Pityoxylon statenense.

. Transverse section of the wood. X20.

Transverse section of the wood near the pith. X 4o.
Radial section. X60.

Tangential section. X60.

Tangential section. x 180.

Tangential section. x 180.

PLATE: HH:

. Transverse section. X 200.

Pityoxylon scituatense.

Transverse section. X60.

- Radial section. X 30.

. Tangential section. 60.
. Tangential section. x 180.
. Tangential section. x 180.

a)

a a eotig

A STUDY OF THE VEGETATION OF THE MESA REGION r
EAST OF PIKE’S PEAK: THE BOUTELOUA FORMA-
TION

I. STRUCTURE OF THE FORMATION.

H. LL: SHANTZ:

(WITH MAP AND SEVEN FIGURES)

THE region under consideration in this study lies at the base
of Pike’s Peak and north and west of Colorado Springs. It is the
portion known as the Mesa and the Garden of the Gods and contains |
3200 to 4ooo hectares (map). While my attention has been confined —
largely to this region, studies have been pushed out in all directions, —
and I have attempted to make myself familiar with the mountain |
and plains conditions of vegetation, as well as that of the area —
under consideration. Especial attention was given to the plains —
which extend eastward from the area first studied. 7:

METHODS. 4

The methods used in the study of the structure and development a

of the vegetation, as well as in the study of the physical factors, are
those used by CLEMENTs' in his ecological studies and need not —
be mentioned here. The exact methods have been supplemented _
by careful field notes and photographs. The greatest care was
exercised in physical factor readings. The soil samples for the
determination of water content were taken with a soil borer, which _
gave a column of soil reaching to a depth of 15°™ and about 2° _
in diameter. :
Relative humidity readings were taken as near as possible to ;

the surface, and also one meter above. A constant record of relative
humidity was obtained by means of the hygrometer at Colorado —
City, and the isolated readings were compared with this record aS
well as with the record of the United States Weather Bureau at ;
Colorado Springs. Temperature readings were taken in the soil

* CLEMENTS, F. S., Research methods in ecology. Univ. Pub. Co., Lincoln,
Neb. 1905.
Botanical

Gazette, vol. 42]

1906] SHANTZ—VEGETATION OF THE MESA Fu

at a depth of 15°™, at the surface of the soil, on the plant, at 10°™
above the soil, and finally 1™ above the surface. A constant record
was taken by means of a thermograph, and the records of the Weather
Bureau were also made use of to check-the results thus obtained.

GARDEN OF THE Go

sonruys ov

SCALE—4CM TO | KM. 33° $0’

Map. ‘

In the measurement of light the writer has used the ordinary
photometric method, but has used the standard derived from the
candle power. Solio paper was exposed to a standard candle for

18 BOTANICAL GAZE?PTE [JULY

15 hours at a distance of 10°. The Hefner-Alteneck lamp burning
acetate of amyl was used as a standard. The diameter of the wick —
was 8™™ and the height of the flame was 40™™. The shade pro-
duced on the Solio paper was used as a standard and copied in per- —
manent colors. Strips of the same sheet of Solio used to make the —
standard were exposed and the time required to produce the standard —
tint recorded. This gave mathematical data and a very simple
means of comparing light intensities. The light at the June solstice —
was about 4.5 seconds. All exposures were made parallel to the
soil surface.
In the diagnosis of the habitat I have given the figures found —
to apply during the time studied. Rainfall, temperature, wind, —
and humidity are averaged for four seasons. The data in water a
content are based on a single season’s work, but on a great many _ : 4
readings. The data on non-available water were obtained by 2 :
taking the soil samples at the time when the plants were dying. —
This water varies not only with the species, but also with the indi- ae
vidual plants. The data as collected were largely at the time of — ay
the dying of Boebera papposa, Salvia lanceolata, Helianthus annuus, —
Verbesina encelioides, and Solanum rostratum, mostly during the :
latter part of the aestival period; and these results are given in
the other diagnoses, since at other times it was impossible unde
natural conditions to obtain such data. Available water is expressed —
- in grams to Ioo grams of dry soil. The duration of each aspect,
as well as many of the factors which are definitely stated, varies from |
year to year. :

eee a”

The species lists are arranged to give an idea of the relative impor-
tance of the species under each heading, the most important species
appearing first. The lists without the species in parentheses are A
for the Mesa region only. Important species of the formation which
do not occur in the Mesa region are included in parentheses. They
will be taken up under the general discussion. In the lists impor-
tant parasitic fungi mcsig ee appear after the species upon which ~
they occur.

Within the formation the following are the terms applied to
the plant associations: consocies, or areas which are dominated by
_ a facies of the formation and which at all periods give the character :

«

1906] SHANTZ—VEGETATION OF THE MESA 19

istic stamp to the vegetation; socéeties, or minor divisions, char-
acterized by principal species and dominant usually over smaller
areas and only during the aspect in which they occur; communi-
ties, or smaller associations, usually of secondary species.

GEOLOGY.

The eastern base of the Rocky Mountains shows a great many
rock systems which are upturned and all come to the surface in or
near this region. Lying on the Archean granite, which forms the
mountains at the west, is found a Cambrian red sandstone, gravel
or lime. The Silurian or Manitou limestone lies next, followed by
the reddish gray quartzite sandstone of the Carboniferpus. East of
this the Garden of the Gods is formed by the great red sandstone out-
crop which is placed in the Permian or in the Triassic—authorities
differ. The Jurassic, which lies next, is followed by the Cretaceous
rock system, represented by the following epochs. The lowest is of
the Dakota—the white sandstone ridge or hogback, and the great.
sandstone ledges. Lying next and buried in most places under.
the talus of the latter is the Benton shale. The most eastern of
the series of hogbacks marks the outcrop of the Niobrara limestone.
The Fort Pierre shale is found in many places east of the lime ridge
and underlies the whole Mesa region. Lying above this is found
the recent Quaternary deposit of gravel of granitic origin.

The sedimentary deposits underlie the entire Great Plains region,
but in most places are covered by the more recent wash from the
mountains. For the geological development and structure of the
Great Plains, as well as for a description of the topography and
climate, the reader is referred to the exceedingly interesting publi-
cation by JoHNson.? The following quotation from this source
(p. 612) gives a very clear idea of the origin of the plains.

The Great Plains are of such vast dimensions it is only in imagination that
they can be regarded as a foot slope to the Rocky Mountains. However, in
the sense that, superficially, ranging down to several hundred feet in depth, they
have been built to a smooth surface by mountain waste, stream-spread to great
distances, they have this character. At the base of the mountains the Plains
mass has a thickness, to sea level, of several thousand feet. It is made up in

2 Jounson, W. D., The high plains and their utilization. Ann. Rept. U. Ss.

- Survey 214: 601-741. 1899-1900.

20 BOTANICAL GAZETTE [JULY

the main of marine-rock sheets with a general inclination eastward, due to broad
regional tilting, in which the plains and mountains have shared together.

But the present surface grade of the Plains is not that of the original tilting.
The surface has undergone a series of transformations. These have all been
accomplished by the eastward-flowing streams from the mountains. In a first
stage the mountain streams, traversing the Plains, cut into the smooth structural
slope, and produced a topography of parallel broad valleys and ridges. In
a second stage they ceased to cut, depositing instead, and refilling the valleys

Fic. 1.—Gully on the east side of the Mesa; alternation between thicket and gra
formation. :

they had excavated, even burying the intervening ridges, to a smooth uppé
surface. The original surface was a product of deformation, the second of @
destructive process of stream erosion, the third a product of stream deposit and
construction, involving the spreading of a waste sheet to great distances and 4
uniform level, and to a depth over the greater valleys often of several hundred feet
In the final and present stage, virtually the same streams have returned to the
earlier destructive habit, and erosion has in large part carried away the high
level plain of stream construction. About midway of the long slope, in the
north-south irregular belt, large uneroded fragments of the smooth constructional :
plain remain. As we have seen above, these fragments constitute the High Plains: _

ba

1906] SHANTZ—VEGETATION OF THE MESA 21

PHYSIOGRAPHY AND SOILS.

The exposure of the Mesa is southeast, the grade being about
18™ to the km. The northwest portion, which is the highest, has an
elevation of 1889™. On the east and south sides of this Mesa the
water has cut deep gullies (fig. 1), which appear older on the south than
on the east, the slope being more gradual and the soil more stable.
The east side of the Mesa is bounded by a low region largely of
clay sand, which slopes gradually to Monument Creek. On the
north side there is a less elevated region which, however, does not
differ markedly from the Mesa itself. On the west side is Camp
Creek, which has cut down into the Fort Pierre clay.

The soil of the Mesa is a gravel mixed with a. limited amount
of clay and humus. The gullies and edges of the Mesa are made
up of Ft. Pierre clay, which is in places mixed to some extent a
the Quaternary gravel which lies above it.

CLIMATE.

Rainjall_—The greatest amount of rain is during the growing
season, the fall and winter, as a rule, receiving very little. As a
result the vegetation is not protected in the least by snow during
winter, nor is there a sufficient amount of water to retard the evapo-
ration from the aerial parts of the plant. There is, as a rule, con-
siderable rain during the summer months from May to September,
but often the rainy season is much shorter, covering, as it did in
1903, only June, July, and August. The rainfall is about 32 to
43°™, but because of the unequal distribution throughout the year,
this affords a rather luxuriant summer growth. This seasonal
variation in rainfall is best illustrated by the following table, which
gives the rainfall in centimeters.

Year | Jan. | Feb. |March| April |. May | June | July | Aug. | Sept.| Oct. Nov. Dec. | Total

TOGT | O.5§ | 6.57 12.07 | 4.67 | 0.52 4 sts. | on one e508 PS-58, | Bees 0.02 | 0.45 tees

1902 | 0.20 | 0.35 | 1.01 | 2.07 | 13.28 | 3.06 | 4.21 | 6.83 | v.40 | 0.38 | 9.05 | 0.55 | 33.20

1903 | 0.15 | 1.77 | 0.93 | 2.41 | 1.57 |12.95 | 1-07 | 6.29 | 1-52 | 0.86 | 2.03 | 0.63 | 32.18

1904 | 0.27 | 0.48 | 0.15 | 0.58 | 10.46 | 9.86 | 7.87 | 6.35 | 5.25 | 9-67 | Trace

There is also a daily variation in rainfall which is of some impor-
tance to the plant. The relative humidity, of course, is much higher
‘during the night than it is during the day, and on this account rain

22 BOTANICAL GAZETTE [JULY

which falls in the afternoon and leaves the ground wet at night
sinks into the soil and does the plant much more good than does}
that which is followed by a clear sky and rapid evaporation.

A study of the rainfall record shows that much more rain falls”
during the afternoon than during the forenoon. During the months —
of May, June, July, and August, 1904, 72 per cent. of the rain fell
in the afternoon; while 71 per cent. of the hours during which rain —
was falling were in the afternoon. The sunshine record (fig. 6) also
makes this plain. :

Relative humidity—A deposit of dew is extremely rare. The
relative humidity therefore seldom reaches 100 per cent. except
during showers. During the day it is generally low, often being |
as low as I per cent.; on account of this, rain or snow is soon evapo- —
rated. The relative humidity is especially low during winter when
there is little rain and when during the day the temperature often
rises to 16°-20° C. The following table gives the relative humid-
ity for each month of the year 1904; and fig. 2 illustrates the dai
variation.

= \ weclze /yoy | Se as E
7, Al we a
SCNSEE EEE
x nena P
~ 6m s blem A b\4m

Fic. 2.—Daily variation in relative humidity.

Jan. | Feb. | Mar. | Apr. May | June | July Aug. | Sept.} Oct. | Nov. Dec.
—— < ——

Masimum. cg G0). Boe} Foo. | eon} 206 04 90 95 | 100 | 100 89 | 100
p aeereeigae ek I 8 6 I Ir 12 9 21 13 12 12 5
verage...... 47 41 42

44.) 58 [Sa st 2 ee gs | oe 1 ee
MES eae BoC! oe”

Wind. —The chief importance of wind is its effect upon the trans- |
piration of the plant and upon the water content of the soil. The

190 6] SHANTZ—VEGETATION OF THE MESA 23

following are the velocities in hm. per hour for the different months
of the year 1904: Jan. 4.6; Feb. 3.3; Mar. 5-7; Apr. 6.09; May
4.7; June 3.7; July 3.5; Aug. 3.2; Sept. a7) <3 ee oe,
4.04; Decug-3.

Temperature-—Extremes in temperature do not occur. The
summer temperature is seldom above 32°C., and the winter tem-
perature is seldom —18°C. The maximum temperature recorded
during the four years 1901-4 was 36°6C., and the minimum for
the same period --28°3C. The following temperatures are for
the year rgo4.

| Jan. | Feb. | Mar. | Apr. | May | June | July | Au. | Sent. | Oct. | Nov. | Dec.
Maximum.| 17.7 21.6 20.5 | 22.8 | 25.5 | 28.3 | 31.6 | 290.4 | 28.3 | 23.3 | 190.3 18.8
Minimum .|—18.3 |—18.3 |—14.4 |—9.4 |—1.1 pag 6.1 7.2 5.5/5.5 i$. 5" | —g008
Mean 42.4 — 2.8 2.2 3-9 7-7") 4251-44507) 28.27) 20-8 1 2903 | 0.4 Sur |e
|

The mean temperature is derived from the daily maximum and
minimum. The daily variation may best be shown by curves from
the thermograph (jig. 3).

JULY 29/904 6

a

ao

+—+—+J

7

f JAN, 12,1904 | \\

aly NM
en ee ee | 6 |am r | | elm

Fic. 3.—Daily variation in temperature:

"4
Seema stasis asta Sosa

A comparison of these curves will show clearly how much greater
is the daily range in winter than in summer. The curve for Jan-
uary 12, 1901, rises higher than the typical winter curve, but is other-
wise normal.

A series of curves showing the variation in temperature between
the soil, soil surface, plant surface, 10°" above the soil surface, and
1™ above will serve to show how different are the conditions of

24 BOTANICAL GAZETTE [JULY

temperature under which the plant lives from those ordinarily
recorded (jig. 4). At the top of the figure is given the sunshine”

SUNLIGHT —
Lew wrensty | | |e] 6] sl asl als |g | w | as] 67
Water Consens | 45% | 374
TEESASEORK . 3 RW Seu ie ais Meee res A “Geen io

er a ee
sf ee \
S44 =
ane Ss
- ee Bie ©
24 et i, Bis ec
res A ty dems =~ Seater N]
= ‘
-, Pe “Ie
wv ‘4 .
4f/ <—s
af VA ge al
"4
Z = AUG, 24 (709
10° SQUTH Slope
AM” Glo0 ’ 7i00 s00 F100 iheo Tkoo ipo Nod 200 3{00 yoo Si00P

Fic. 4.—Variation in temperature at different levels.

record, together with the light intensity for each hour of the day-
The water content was determined twice, as recorded in the figure.
The plant surface temperature record was taken on a mat of :
Bouteloua oligostachya, and the quadrat was situated on a south
slope. :
The extreme conditions at the surface of the soil may account —
to some extent for the dying of the lower stem leaves, so often noted
among perennials as well as annuals. :
Simultaneous readings on north, south, east, and west slopes
give the curves for soil and soil surface temperatures shown in fig. 5:
The water content was recorded twice in each quadrat and is als0
given in the figure; curves of soil temperature are given at the bot
tom of the figure. Some idea of the temperature at the various —
levels may be obtained by comparing these curves with those of ;
jig. 4. The readings shown by figs. 4 and 5 are simultaneous. 14
Light.—The sunshine records taken show 51 to 80 per cent. of
possible sunshine. The difference between possible sunshine for
the forenoon and afternoon is seven to nine hours per month during ;

1906] SHANTZ—VEGETATION OF THE MESA 25
LIGHT. dM | 70
I] iITYS | 7

Eo 2
iw Seconos|E, fi 2
°

SRS eae Meo Siete SAS lee ely

Am ét00 to 800 ty joo ito moo foo 200 300 foo “S00 PM

Fic. 5.—Variation in temperature and light intensity on different slopes.

the period of growth. This is due to the mountains which shorten
the period of illumination for the afternoon. The rains and cloudy

AM PM.
8 Se ee, Sent | hee Ce Bie a4. F

sl et] ee

” - = ase oe es
uy IF < wae a
Zu] et eetene st
ae = = —— > — =

<< = SSS eee

= se = = afevellitte ST os

i) tet ay i
—- —= —

20\ = cummings nee sees Sa asta Pinte Bae
ar ===> => Saas

. oe = ——+— — so mae | 8 jit—

Fic. 6.—Sunshine record.

26 BOTANICAL GAZETTE [JULY a

sky occur most frequently during the afternoon, which on this account
also receives much less sun than does the forenoon. The record
for sunshine for June and July 1904 makes this clear (fig. 6).

The difference in the light received by the east and west slopes, —

together with the resulting differences in temperature, relative

humidity, and water content, is of importance in explaining the |

vegetation of these exposures.

The Bouteloua (grama grass) formation.

This formation occupies practically the whole Mesa region and —
the low land surrounding it. It extends for many miles north, —
south, and east, but no attempt has been made to determine its ©
limits. It seems to be the formation most typical of the high plains

and extends eastward far into western Kansas and Nebraska.

The season of growth may be divided into two periods: the ;
vernal, or in this case the spring and early summer period; and —

the aestival, or late summer and autumn period. Each of these
grand periods may be divided into two periods: the first into the
prevernal and vernal, the second into the aestival and autumnal.

PREVERNAL ASPECT.

Habitat—Physical and available water content very low. Rain- —
fall o.48-2.43°™ (April 1904, 4.68°™); ay. daily, 0.008°™. Rela-—
tive humidity: mean, 44 per cent.; range 1-100 per cent. Wind —
6.09'™ per hour. Temperature: mean 7°2 C.; mean max. 14°4 C.}
mean min. o° C.; range —11°1 to 25° C.; soil, 13°C. Light dura
tion 66 per cent., exposure varied, cover open, soil clay to. gravel.

Duration April.

PRINCIPAL SPECIES: Leucrocrinum montanum Nutt., Townsendia exscap4
(Richards) Porter, Pulsatilla hirsutissima (Pursh) Britton. ;

SECONDARY SPECIES: Cymopterus acaulis (Pursh) Rydb., Phellopterus :

montanus Nutt.

The winter conditions are xerophytic, there being very little
rain and seldom a snow cover. The mean relative humidity is —
low—40 to 50 per cent., and sometimes falling as low as 1 per cent. —
The temperature in winter rarely falls below —18° C. and often rises ;
above 16° C. The records show 56 per cent. of possible sunshine —

1906] SHANTZ—VEGETATION OF THE MESA 27

and the surface of the soil rises to a temperature much higher than
that of the air.

To understand and explain the appearance of the vernal and
prevernal flora it is necessary to take into account the winter
condition. The water content is low at the time of the appearance
of the first flowers. The north slopes have a higher percentage of
water than the other exposures, and although the temperature is
lower it is here that the greatest number of spring flowers are pro-
duced. Only very resistant species seem to be able to survive the
long dry winter and produce flowers in the spring on the south
slopes. The high temperature which the soil of this exposure reaches
during the winter would surely start growth at a period when
such development would be disastrous to the life of the plant.
This probably explains the abundance of the north slope vernal
flora and the paucity of the south slope flora during the same
period.

Before the spring rains have begun, at the end of the long dry
period, this prevernal flora makes its appearance. These plants
are never very abundant on the Mesa proper, but appear in great
numbers on the hillsides. In each case the flowers appear either
without any foliage or with very little.

The most prominent society of this period is the Pulsatilla soci-
ety, characterized by P. hirsutissima. Its distribution within the
region studied is limited to the north slopes and it is never found on
the south slopes. The plants are often very numerous and consti-
tute almost the only growing vegetation of this period; forming a
zone along the north and east slopes of the Mesa which is only inter-
rupted at places of south or southern exposure.

Leucocrinum montanum forms a society which is less exclusive
than’the former and is at the same time less distinct. It reaches
its maximum development on north crests, but may occur in almost
any situation except the south exposure. Over the greater part
of the Mesa L. montanum is mingled with Townsendia exscapa,
and these two plants constitute the only vegetation of the Mesa top
at this period.

Cymopterus acaulis and Phellopterus montanus seldom form
communities. In their distribution they show a marked alternation,

28 BOTANICAL GAZETTE [yuLy

C. acaulis occurring on the slopes and crests, usually in the gravelly
loam, while P. montanus is limited to the clay of the lowland.
The flowers of these species are produced early and are short-
_lived, most of the foliage being produced after the flowers and con-
tinuing during the rainy vernal period, after which the surface parts
disappear and the living parts lie buried until the following spring. —

VERNAL ASPECT. |

Habitat—Physical water: in clay 1 3-17 per cent.; in gravelly”
loam 4.5-9 per cent. Non-available water: in clay 8.5-10 per
cent.; in gravel 1.5-2.5 per cent. Available water: in clay 5.0-_
9-3 to roo of dry soil; in gravel 3.2-7.28, Rainfall 12.7-
27-9°"; ay. daily o.3°™. Relative humidity: mean 54 per cent.;
Tange II-too per cent. Wind 5.33'™ per hour. Temperature:
mean 14:4 (C.; mean max. 20-5 C.; mean min. 6°4 C.; range —2.2 :
—34°4C.; soil 12—25°C.; soil surface to 49°C. Light duration —
67 per cent. Exposure varied, cover open, soil clay to gravel. Dura-
tion May 1 to July rs. : |

PRINCIPAL SPECIES: Senecio oblanceolatus Rydb.,- (Thelesperma _ inter-
medium Rydb.), Yucca glauca Nutt., Kellermannia yuccogena Ell. & Ev., |
Pleospora phragmospora Dur. & Mont., Astragalus Drummondii Doug]., Pent-
stemon angustifolius Pursh, P. secundiflorus Benth., (Opuntia polyacantha Haw.), :
(Carex stenophylla Wahl.), (Puccinia caracena DC.), Astragalus bisulcatus —
(Hook.) Gray, Euphorbia robusta (Engelm.) Small, Uromyces scutellatus
(Schrank) Léy., Echinocereus viridiflorus Engelm., Arenaria Fendleri Gray,
Sophora sericea Nutt., Uromyces hyalinus Pk., (Oreocarya suffruticosa [Torr]
Greene), (Ipomoea leptophylla Torr.). F

SECONDARY SPECIES: Lesquerella montana (Gray) Wats., Tetraneuris :
glabriuscula Rydb., Aragallus Lambertii (Pursh) Greene, (Astragalus mol-
lissimus Torr.), Astragalus crassicarpus Nutt., Lappula occidentalis (Wats-)
Greene, Allium reticulatum Don, Oreocarya thyrsiflora Greene, Euphorbia
glyptosperma Engelm., Hymenopappus cinereus Rydb., Thalesia fasciculata
(Nutt.) Britton, Mertensia linearis Greene, Pentstemon Jamesii Benth., Erio- ;
gonum alatum Torr., Cactus viviparus Nutt., Malvastrum coccineum ( “ ) ;
Gray, Cheiranthus arkansanus (Nutt.) Greene, Anogra coronopifolia (T. & G-)_
Britton, Gaura coccinea Pursh, Euphorbia serpyllifolia Pers., Tradescantia
scopulorum Rose, Thelesperma gracile (Torr.) Gray, Astragalus Shortianus
Nutt., Nothocalais cuspidata (Pursh) Greene, Erigeron pumilus Nutt., E. flagel-
laris Gray, E. glandulosus Porter, E. canus Gray, Carex filifolia Nutt., C. pent
sylvanica Lam., Vicia americana Muhl., Aecidium porosum Pk., Quincula

1906] SHANTZ—VEGETATION OF THE MESA 29

lobata (Torr.) Raf., Leucolene ericoides (Torr.) Greene, Meriolix serrulata
(Nutt.) Walp., Lithospermum linearifolium Goldie, Anogra albicaulis (Pursh)
Britton, Poa longipeduncula Scribn., Salvia lanceolata Willd., Gaura parvi-
flora Dougl., Hedeoma nana (Torr.) Greene, Antennaria imbricata A. Nels.,
Evolvulus pilosus Nutt., Thelesperma intermedium Rydb., Sitanion elymoides
(Torr.) Greene, Oreocarya suffruticosa (Torr.) Greene.

The vernal period, with which the prevernal is sometimes more
or less blended, is ushered in by the spring rains and usually extends
from about the first of May to the middle of July. The water content
is higher at this period than any other, as is also the relative humid-
ity. Extreme temperatures are not recorded, and the conditions for
growth are more favorable than at any other time during the year.

This aspect is marked by the appearance of a great number of
seedlings and by many showy flowering plants. The floral display
is almost entirely of perennial plants. The earliest species generally
appear on the north slopes or north crests, a position protected
from the high temperature and excessive loss of water during the
winter period.

Socteties.

Senecio oblanceolatus society.—This society is by far the most
important of the vernal period. It reaches its maximum develop-
ment in the large gullies on the south side of the Mesa, but the species
is distributed over practically the whole area.

Yucca glauca society (fig. 7).—This species is one of the mcst con-
spicuous plants of the Mesa region and in many places becomes
dominant for this aspect. Since the plant is perennial, it is at all
times one of the most characteristic of this part of the formation.
Species of secondary importance in this society are Senecio
oblanceolatus, Euphorbia robusta, Lesquerella montana, Echinocereus
viridiflorus, and Mertensia linearis. This society is found on the
gravelly soil, often on crests and slopes where the water content is
especially low.

Pentstemon angustijolius society——On crests in the south part
of the Mesa this society reaches its best development. Here the
species dominates areas of many square meters, almost to ‘the exclu-
sion of any other species. The-chief secondary species of this society
are Lesquerella montana and Echinocereus viridiflorus.

30 BOTANICAL GAZETTE [JULY

Euphorbia robusta society——This society occurs on most of the
hilltops and over rather large areas of the north Mesa. E. robusta
is less dominant than the controlling species of the societies already
mentioned. Echinocereus viridiflorus is in point of numbers more
abundant but it is comparatively a very inconspicuous plant. Sen-
ecto oblanceolatus is not dominant in this society, but ranks second
in importance to Euphorbia robusta; the society very naturally

Fic. 7.—Typical Mesa: Bouteloua formation; Yucca glauca society.

grading into the Senecio oblanceolatus society almost imperceptibly.
Secondary species are Lesquerella montana, Vucca glauca, Oreocaryd
thyrsiflora, Aragallus Lambertii, Mertensia linearis, and Erigeron
pumilus. The soil is a coarse, gravelly loam; water content 6-9 per
cent.

Arenaria Fendleri society.—On crests in coarse gravel or gravelly
loam, where the water content is low, this society is found. A:
Fendleri is dominant, but many other species help to make up

bes

1906] SHANTZ—VEGETATION OF THE MESA 31

the society. Among the- more prominent secondary species are
Tetraneuris glabriuscula, Oreocarya thyrsiflora, Hymenopappus
cinereus, Meriolix serrulata, Pentstemon angustifolius, Trades-
cantia scopulorum, and Lithospermum linearis.

Pentstemon secundiflorus society.—No species of this aspect is
more dominant than is P. secundiflorus. On the crests of the east
and north sides of the Mesa it forms an extensive society. Les-
querella montana, Echinocereus viridiflorus, and Evolvulus pilosus
are secondary species.

Astragalus bisulcatus society.—In the clay on the south, east,
and west sides of the Mesa, large clumps of this species are very
conspicuous at this time of the year. Its maximum development
is at the bottom or near the bottom of the hillsides. It usually
occurs alone, but we may also find it associated with Sophora sericea,
Quincula lobata, Lappula occidentalis, Allium reticulatum, Mal-
vasirum coccineum, and Euphorbia glyptosperma.

Astragalus Drummondii society.—This is an especially promi-
nent society on north and west slopes, occupying about the same
relative position as the A. bisulcatus society, but more extensive.

Sophora sericea society.—Although badly affected with Uroymces
hyalinus, this species becomes the dominant plant in the clay draws
of the south Mesa. The chief secondary species associated with
it are Lappula occidentalis, Allium reticulatum, Malvastrum cocci-
neum, and Quincula lobata.

Communities.

Among the secondary species are found a number which form
communities. These are generally of limited extent, but are of
species which are widely scattered throughout the formation. The
following are the more important communities: Tetraneuris glab-
_riuscula, on crests; Lappula occidentalis, in semiruderal situations;
Erigeron flageolaris, at the base of north and west slopes, or on the
north and west sides of clumps of oak which have entered from the
foothill thicket formation; E. glandulosus, on north crests; Carex
filijolia, on portions of the north Mesa and west slopes; Quincula
lobata, in clay; Opuntia polyacantha, either in clay, or on the gravel
crests; Leucolene ericoides, on south crests and slopes and other

52 BOTANICAL GAZETTE [JULY

xerophytic situations; Pentstemon Jamesii, on clay knolls in the
gullies of the south Mesa; Malvastrum coccineum, in semiruderal
situations; Gaura coccinea and Thelesperma gracile, on open coarse
gravel of north Mesa; Poa longipeduncula, on north slopes; Salvia
lanceolata, in semiruderal situations; and Antennaria imbricata,
on northwest and rarely northeast slopes. :

Most of these communities are closed and contain very few if i
any other species belonging to this aspect. Any of the species —
which form societies will also be found to form communities; in
fact some of the societies are merely associations of communities.

General. a.

The chief societies of the Mesa top are the Yucca glauca (fig. 6)|
and the Senecio oblanceolatus societies. These become more or less a
mixed in places on the north Mesa. In many places there is formed ;
a mixed society which varies greatly and can only be regarded as
a society made up by mixing the other societies and by the addition
of widely distributed secondary species. The Mesa top contains —
besides the two prominent societies mentioned above, a society”
marked by Euphorbia robusta. These three societies alternate, |
the last named occurring on the north part, the more open part of
the formation, in gravelly loam, where the water content is from
6-10 per cent. The Yucca glauca society occupies a somewhat more
humid region—the crests and Mesa top, especially where the soil
is a rocky, gravelly loam, with water content from 7-12 per cent. 4
The Senecio oblanceolatus society reaches its maximum development
in the gullies, where the loam has a water content of 10-15 per cent

In addition to these well-marked societies, the following plants
occur in varying numbers over practically the whole Mesa top
Lesquerella montana, Pentstemon angustifolius, Aragallus Lamberti
Astragalus crassicar pus, Oreocarya thyrsiflora, Erigeron pumilus, Eq
canus, Astragalus Shortianus, and Mertensia linearis. Any oF all
of these species may occur in the societies noted above.

The gravel crests with a water content of from 4. 5-9 per cent
are the most xerophytic situations in the formation; and here are
found several societies that alternate. Most of the crests of the
north and east sides of the Mesa are occupied by the Penistemonm

My
(3
a
4
a
©
i

yi
t

i a i i a a

1906] SHANTZ—VEGETATION OF THE MESA 33

secundiflorus society; the crests of the south Mesa by the P. angusti-
jolius society; and the west crests in either situation or on the west
side by the Arenaria Fendleri society. The alternation between
the first two societies is very marked and may be explained partly
by the facts of development. P. secundiflorus occurs on soil that
is less disintegrated, on coarse gravel, or coarse gravelly loam. P.
angustijolius occurs in older gravelly loam, where the water content
is from 2-4 per cent higher; it seems to be more at home on the
plains, while P. secundiflorus thrives best in the foothill region. These
societies also alternate with the Arenaria Fendleri society.

There are in this aspect no well-developed societies on the hill-
sides. The flora of the slopes however, is rather rich and varied.
Practically all of the societies are represented here and one may
also find many of the secondary species. Crest forms are especially
abundant on the south and east slopes.

The alternation between the Astragalus bisulcatus society and
the A. Drummondii society is partly due to the difference in soil.
A. bisulcatus occurs in clay and is best developed on south and west
exposures, usually at the base of the hills. North and west exposures
are the most suitable for A. Drummondii, which likewise occurs
at the base of the hills.

On the lower land surrounding the Mesa the flora is largely
of the Astragalus bisulcatus society and of the Sophora sericea society,
together with the following communities: Lappula occidentalis,
Quincula lobata, Opuntia polyacantha, Malvastrum coccineum, and
Salvia lanceolata. This vegetation is in the Ft. Pierre clay, a heavy
soil with a water content of 13-17 per cent., 8-10 per cent. of which
is not available.

As seen by this arrangement, there is zonation exhibited by
these societies. This, however, is not very well marked, and the
alternation within the zones is much more distinct than the zones
themselves.

The reason for this alternation within the formation is to be found
in the physical nature of the soil. The soil of the Mesa is a gravel,
mixed with a limited amount of humus and silt, or even clay, and
is derived entirely from partly decomposed granite and plant remains.
The soil is pervious and there is consequently very little run-off,

34 BOTANICAL GAZETTE [JUL c

except during very heavy rains. The total water content varies
with the soil composition from 5-14 per cent., and all but 2-4 per”
cent. is available to the plant. The crests are of a much looser
‘soil, almost pure gravel in places, but generally mixed with clay and
silt. The water content here is from 3-4 per cent. lower than on
the Mesa top and the formation is much more open. The clay is
closely packed and a large percentage of water which falls runs off. .
The water content is usually less than 17 per cent. and is often as
low as 13 per cent., while the non—available water seems to vary
with the plant and the slight differences in the amount of foreign’
substances in the clay from 8.5-10 per cent. After a rain the soil
is easily baked to form a hard crust, and when the soil becomes
dry, especially during winter, it cracks open to a considerable
depth.

The preference which certain plants show for north and wes
slopes is easily explained by a glance at the sunshine record for ull :
and July. The morning sun heats the east slopes, and as it rises
higher the south slope is strongly heated. This hastens trans
tion and water loss. The afternoon is cloudy and very likely rainy
The west slope is consequently not strongly illuminated, the soil ' 13
temperature is from 2—5° C. lower than on the east and south slopes
and the water content is from 1.5-5 per cent. higher. It is the leas
xerophytic of any situation in the formation.

AESTIVAL ASPECT.
Habitat.—Physical water: in clay 10-13 per cent.; in gra
2.5-4.5 per cent. Non-available water: in clay 8.5—-10 per cent.
in gravel 1.5-2.5 per cent. Available water: in clay 2.3-3- om
to roo of dry soil; in gravel 1-2.18™ to roo8™. Rainfall 7. SF
10°™; av. daily 0.137°™. Relative sree mean 51 per cent.
Tange g-Ioo per cent. Wind 4.3545" per hour. Tempera
mean 18.8° C.; mean max. 25° C.; mean min. 10.5° C.; range 2-
36.6° C.; soil 18-29° C:; soil sisrhace to 55°C. Light duration
per cent. Exposure eel cover open, soil clay to gravel. D
tion July 15 to September 1s.
Facts: Bouteloua oligostachya (Nutt.) Torr., B. hirsuta Lag., (Andropo!
scoparius Mich.), (A. furcatus Muhl.), (Calamovilia longifolia [Hook.] Hack

ea re eh ee he ee en ee ee

1906] SHANTZ—VEGETATION OF THE MESA 35

Muhlenbergia gracillima Torr., Agropyrum occidentale Scrib., (Koeleria cris-
tata [L.] Pers.).

PRINCIPAL SPECIES: Artemisia frigida Willd., (Thelesperma intermedium
Rydb.), (Schedonnardus paniculatus [Nutt.] Trel.), Gutierrezia Sarothrae
(Pursh) Britt. & Rusby, (Grindelia squarrosa [Pursh] Dunal), Chrysopsis
villosa (Pursh) Nutt., (Eriogonum annuum Nutt.), (Artemisia canadensis
Michx.), Lupinus so Pursh), (Carduus plattensis Rydb.), Aristida
longiseta Steud., Psoralea tenuiflora Pursh., Aecidium psoralea Pk., Boebera
papposa (Vent.) Rydb., Plantago Purshii R. & S., (Selaginella inks Rydb.),
(Eriogonum effusum Nutt.), (Sporobolus cryptandrus [Torr.] Gray), (Eriogonum
annuum Nutt.)

SECONDARY SPECIES: Oreocarya thyrsiflora Greene, Petalostemon oligo-
phyllus (Torr.) Rydb., P. purpureus (Vent.) Rydb., Euphorbia glyptosperma
Engelm., Thelesperma gracile (Torr.) Gray, Gaura coccinea Pursh, Tetra-
neuris glabriuscula Rydb., Malvastrum coccineum (Pursh) Gray, Atheropogon
curtipendulus (Michx.) Fourn., Sideranthus spinulosus (Nutt.) Sweet, Lacini-
aria punctata (Hook.) Kuntze, Eriogonum Jamesii Benth., Munroa squarrosa
(Nutt.) Torr., Euphorbia serpyllifolia Pers., Chenopodium leptophyllum (Moq.)
Nutt., Mentzelia nuda (Pursh) Torr. & Gray, Argemone intermedia Sweet, Phy-
salis comata Rydb., Atriplex argentea Nutt., Potentilla pennsylvanica L., Asclepias
pumila (Gray)Vail, Bouteloua prostrata Lag., Helianthus pumilus Nutt., Sitanion
elymoides Raf., Muhlenbergia gracilis Trin., Artemisia gnaphalodes Nutt., Stipa
comata Trin. & Rupr., Stipa Vaseyi Scrib., Allionia linearis Pursh, Artemisia
canadensis Michx., Leucolene ericoides (Torr.) Greene, Picradeniopsis oppositi-
folia (Nutt.) Rydb., Hedeoma nana (Torr.) Greene, Stipa neo-mexicana (Thurb.)
Scrib., Chenopodium oblongifolium Wats., Anogra coronopifolia (T. & G.)
Britton, Leptilon canadense (L.) Britton, Helianthus annuus L., Andropogon
furcatus Muhl., Solanum rostratum Dunal, Ptiloria ramosa Rydb., Cheno-
podium album L., Helianthus petiolaris Nutt., Quincula lobata (Torr.) Raf.,
Grindelia squarrosa nuda (Wood) Gray, Carduus undulatus Nutt., Carduus
plattensis Rydb., Gaura parviflora Dougl., Potentilla coloradensis Rydb., Eri-
ogonum alatum Torr., Euphorbia stictospora Engelm., Mentzelia decapetala
(Pursh) Urban & Gilg, Andropogon scoparius Michx.

An increase in temperature, a decrease in rainfall and relative
humidity, together with the resulting decrease in water content
of the soil mark the appearance of the aestival period. The per-
centage of water in the soil is for this period 10-13 per cent. for
clay and 2.5-4.5 per cent. for gravel.

This aspect is characterized by the flowering of most of the annual
species and by the predominance of the grasses and composites.
The facies of the formation are the dominant species of this aspect

36 BOTANICAL GAZETTE [JULY

and in consequence the principal species are less conspicuous than _
during the vernal period.

Consocies.

Consocies or areas dominated by the facies of the formation _
will be discussed later, and need only be mentioned here. ae
Bouteloua oligostachya consocies.—This consocies is almost as
extensive as is the formation, for this species is by far the most abun- af
dant of any found in the region studied. A discussion of the con-_
socies is practically a discussion of the typical grama grass formation —
and will be taken up later. The highest development of this con-
socies is on the Mesa top, where the water content of this pericd |
in the gravelly loam is 4-8 per cent. Ff

Bouteloua hirsuta consocies.—This consocies occupies a more —
xerophytic habitat, where the water content is 2. 5-4-5 per cents =
It occurs on the crests and on the north portion of the Mesa in the
gravelly soil. With this plant are generally associated Artemisia —
jrigida, Atheropogon curtipendulus, Aristida longiseta, Bouteloua
oligostachya, Gutierrezia Sarothrae, and many crest species. Condi- —
tions here are the most xerophytic of any situation in the habitat.

Muhlenbergia gracillima consocies.—This consocies is character
istic of the clay flats where it reaches its best development. It is q
hot uncommon to find places which are dominated by this species —
almost to the exclusion of everything else. As a rule, howevel, —
one finds here Bouteloua oligostachya, Schedonnardus paniculatus, —
Artemisia frigida, Gutierrezia Sarothrae, Munroa squarrosa, Boebert t
papposa, Plantago Purshii, Picradeniopsis oppositijolia, Euphorbia
glyptosperma, Argemone intermedia, Atriplex argentea, Agropyrom
occidentale, Malvastrum coccineum, and many other secondary
species. The habitat is xerophytic, in clay or loam where the water
content varies with the soil composition from 17-13 per cent.; the
available water being from 2-3.5%" per roo of dry soil.

Agropyron occidentale consocies.—This is not so important in
Mesa region as it is farther east. It occurs, however, in the cla
and here is usually associated with Muhlenbergia gracillima, Boule
loua oligostachya, B. prostrata, and Atriplex argentea.

i
;
§
a
: -
3
4
}
4

1906] SHANTZ—VEGETATION OF THE MESA 37

Societies.

Artemisia jrigida society—This is by far the most important
society of the region. It occurs at the heads of the gullies and on
the more depressed places of the north Mesa. It is also important
on alluvial fans and areas where there has been a secondary suc-
cession. Where this species is abundant, as a rule it shuts out all
other plants with the exception of the taller species, such as Argemone
intermedia and Stipa Vaseyi. This society can be distinguished
for miles because of the silvery appearance of the plant, which is
so widely distributed over the entire Mesa that it would be considered
a facies of the formation if it were not for the fact that more extended
study shows it to be local in its distribution.

Gutierrezia Sarothrae society—This composite is rather evenly
distributed over the Mesa region, but it can never be said to replace
the grasses which are characteristic of the formation. It does dom-
inate rather large areas, however, particularly in the southern part
of the Mesa, where it is found associated with many of the character-
istic plants of the Mesa top. It does not occur so commonly in
the purer gravel soil as in the clay and gravelly loam.

Chrysopsis villosa society.—This society is of considerable impor-
tance on the north portion of the Mesa, where it occurs in the Bou-
teloua hirsuta consocies.

The Aristida longiseta society is not extensive, but dominates
south and east crests and slopes. The Psoralea tenuiflora society
is extensive, reaching its best development on the hillsides.

The rainy vernal period favors the development of a number of
annuals which come into bloom at this time. The most important
of these is Boebera papposa, which has a very even distribution
throughout the region studied. It occurs as a ruderal plant, usually
from 4-10°™ high and bearing very often only one head. In point of
numbers it probably exceeds all but the facies of the formation.
However, it succeeds best as a ruderal, and in the formation the small
plants may be as numerous as 996 per quadrat and still not be espe-
cially noticeable. Wherever there are open spaces in the formation,
this society is found.

Plantago Purshii also occurs as an important annual in the forma-

38 BOTANICAL GAZETTE [yuLy

tion. It is also successful as a ruderal, but at places within the
formation may become far more numerous than any other species.

Communities.

The following communities also occur: Schedonnardus panicu-
latus, near the mountain and in clay; Atheropogon curtipendulus,
on north slopes; Sideranthus spinulosus, on south slopes and crests;
Atriplex argentea, in ruderal clay; Bouteloua prostrata, in clay south
of the Mesa, also in ruderal or semiruderal habitats; Sitanion ely-
modes, on south slopes; Muhlenbergia gracilis, on north slopes;
Artemisia canadensis, on north and west slopes; Leucolene ericoides,
crests and xerophytic places; Andropogon furcatus, on north Mesa
in gravel; Andropogon scoparius, on gravel crests; Thelesperma
gracile and Gaura coccinea continue from the previous aspect.

Within this area there is one family of Oonopsis joliosa (Gray)
Greene, which is about three years old and has spread to cccupy
Tes a

General.

In considering the aestival aspect as a whole, much is found
that will be discussed under the formation. Zonation during this
aspect is shown as in the preceding aspect. The Mesa top is domi-
nated by the typical formation—Bouteloua oligostachya consocies—
the crests by the B. hirsuta consocies, the hillsides by the typical
formation tending towards the B. hirsuta consocies, and the low
lands surrounding either by the typical formation or by this alter-
nating with the Muhlenbergia gracillima or Andropogon occidentale
consocies.

This zonation is largely due to differences in water content.
The Mesa top and the slopes have nearly the same water content,
there being about 2-3" of available water; the crests have a less
amount, 1-2" ; while at the base, in the clay, the available water
is from 2. 3-3,88™,

The greater part of the Mesa top is occupied by the Bouteloua
oligostachya consocies. Almost any of the other species noted
under this aspect, whether they are primary or secondary, may be —
found associated with B. oligostachya. The most noticeable forms —
found on the Mesa at this time are B. oligostachya, Muhlenbergia

1906] SHANTZ—VEGETATION OF THE MESA 39

gracillima, Bouteloua hirsuta, Artemisia frigida, Gutierrezia Sar-
othrae, Boebera papposa, Oreocarya thyrsiflora, Chrysopsis villosa,
Schedonnardus paniculatus, Petalostemon oligophyllus, P. purpureus,
Psoralea tenuiflora, Theles perma gracile, Gaura coccinea, Euphorbia
gly ptosperma, Atheropogon curtipendulus, Sideranthus spinulosus,
Lacinaria punctata, Eriogonum Jamesii, E. effusum, Asclepias
pumila, Helianthus pumilus, Sitanion elymoides, Artemisia gnaph-
alodes, Castilleia integra, Erigonum alatum, Pentstemon unilateralis,
‘Stipa Vaseyi, and Euphorbia stictos pora.

Besides the typical formation, the north Mesa is occupied by
the Bouteloua hirsuta consocies. In this consocies the following
8roups occur: the Chrysopsis villosa society occupying rather lim-
ited areas, low crests, and south slopes; and the following com-
munities: Sideranthus spinulosus, Artemisia gnaphalodes, Andro-
pogon furcatus, and A. scoparius.

The crests are the most xerophytic and are occupied by the Boute-
loua hirsuta consocies. This may alternate,. however, with the
B. oligostachya consocies. Occurring within the former consocies
are often found the Gutierrezia Sarothae, Chrysopsis villosa, and the
Aristida longiseta societies, as well as the following communities:
Silanion elymoides, Muhlenbergia gracilis, Artemisia gnaphalodes,
Andropogon Scoparius, and Tetraneuris glabriuscula. The following
Plants are also abundant on these crests: Oreocarya thyrsiflora,
Chenopodium leptophyllum, Stipa comata, and S. neo-mexicana.

The hillsides and ‘slopes have usually about the same vegetation
as the Mesa top, but the crest forms may be more abundant.

Passing to the lowlands, the Bouteloua oligostachya consocies
is found alternating with the Muhlenbergia gracillima consocies
and also the Andropogon occidentale consocies. The chief societies
of the Bouteloua oligostachya consocies are the Gutierrezia Sarothrae
and Artemisia jrigida societies. In the Muhlenbergia consocies
are found the Bouteloua prostrata and Atriplex argentea communities.

Marked alternations sometimes occur between secondary species.
Petalostemon oligophyllus occurs on south and east slopes, and P :
burpureus on north and west slopes, where the water content 1s
from 1-2 per cent. higher; Muhlenbergia gracile, Koeleria cristata,
and Poitentilla pennsylvanica are usually found on north slopes;

40 BOTANICAL GAZETTE [yuLy

while Aristida longiseta, Sitanion elymoides, Stipa comata, S. neo-
mexicana, Physalis comata, and Ptilora ramosa are found on south
slopes and crests.

AUTUMNAL ASPECT.

Habitat—Physical water: in clay 8.5-10 per cent.; in gravel
1.5-2.5 per cent. Non-available water: in clay 8.5-10 per cent;
in gravel 1.5-2.5 per cent. Available water: none in surface soil.
Rainfall 1.62-4.03°™; av. daily .006°™. Relative humidity: mean
49 per cent.; range 12-100 per cent. Wind 4.66" per hour. Tem-
perature: mean 11.6°C.; mean max. 18.8°C.; mean min. 2.7°C,
range —5.5°—27.2°C.; soil 18-25°C.; soil surface to 4o°C. Light
duration 60 per cent. Exposure varied, cover open, soil clay to
gravel. Duration September 15 to November 1. :

PRINCIPAL species: Artemisia frigida Willd., Gutierrezia Sarothrae (Pursh)
Britt. & Rusby, (Grindelia squarrosa [Pursh] Dunal), Senecio spartioides Torr.
& Gray, Chrysopsis villosa (Pursh) Nutt., Chrysothamnus graveolens (Nutt)
Greene.

SECONDARY SPECIES: Lacinaria punctata (Hook.) Kuntze, Oreocarya
thyrsifloria Greene, Eriogonum Jamesii Benth., Aster polycephalus Rydb.,

squarrosa (Pursh) Dunal, Leptilon canadense (L.) Britton, Machaeranthera
viscosa Nutt., Chrysothamnus_plattensis Greene, Grindelia squarrosa nuda
(Wood) Gray, Eurotia lanata (Pursh) Mog.

During the month of August the rainfall decreases markedly,
and is only slight during September. The temperature at this time
is as high as at any time during the year, and the result is the rapid
loss of water by the soil. Although there is still 8-10 per cent. of
water in clay and 1.5-2, 5 per cent. in gravel, it is doubtful if there —
is any available water in the surface soil. |

Although many plants continue to bloom, vegetative growth is
practically stopped for all annuals and greatly decreased for peren-
nials. There must still be some available water, but all the annual -
plants which would ordinarily continue to grow and bloom if sup-
plied with only a limited amount of water, have dried up at the

1906] SHANTZ—VEGETATION OF THE MESA 41

beginning of this period. The grasses are dried, and although
they are still a prominent part of the vegetation, they are not a living
part. It is an exceedingly xerophytic time, and the plants which
are found in this aspect appear throughout the vernal and aestival
periods and are now only blooming and ripening their seeds.

Artemisia frigida and Muhlenbergia gracillima continue to occupy
a most important place. Senecio spartioides forms in places an
extensive society; while the Gutierrezia Sarothrae society is even
more noticeable than during the aestival period. Chrysothamnus
graveolens, a large shrubby composite, forms a small society within
this region, but farther east occupies larger areas; it is one of the
most showy plants of this aspect. Aster polycephalus and Machae-
ranthera cichoriacea form rather extensive communities in the more
open parts of the formation. Chrysopsis villosa, Lacinaria punctata,
Oreocarya thyrsiflora, Eriogonum Jamesii, Tetraneuris glabriuscula,
Petalostemon oligophyllus, P. purpureus, Aristida longiseta, Grin-
delia squarrosa, G. squarrosa nuda, Artemisia canadensis, and A.
§naphalodes have continued from the preceding pericd.

The end of this period is not well marked. The plants are dry
and resistant, and although frost kills the plants which have a more
liberal supply of water, some of these species may continue to bloom
as late as December 10. During this late period Senecio oblanceo-
latus, Argemone intermedia, Lesquerella montana, and a number
of other species form rosettes which continue throughout the winter.

Structure of the formation as illustrated by typical quadrats.

Passing now from the aspects to the formation as a whole, the
structure may be illustrated best by a number of permanent quad-
rats. Those species which form mats cannot be well represented
‘n numbers per square meter, and on this account the percentage
of surface covered is given instead. The numbers which are also
Siven for these species indicate single plants or seedlings. An esti-
mate is also given of the total amount of surface covered by plant
growth.

The following quadrat is typical of the Bouteloua oligostachya
“onsocies—the most typical portion of the Bouteloua formation.

42 BOTANICAL GAZETTE [yuLy

Bouteloua oligostachya ....134 22% Senecio spartioides............... 4
Muhlenbergia ee ee 5 7% Sideranthus spinulosus........... 12
Artemisia frigida.......... GO, Poevers. PADDOGA. os. ee ec 81
Senecio oblanceolatus...... 9 PrANCAGD PUM. 8.2. 25 cy eo ee 2
Aristida longiseta.......... I Polygonum aviculare............. I
Astragalus Shortianus...... I Townsendia exscapa............- I
Schedonnardus paniculatus. 1 Cyn. ‘argentewm: 24. 30>. Sens

Chrysopsis villosa.......... Total surface worverell. ...42%

Water content: vernal ne 8-13%; aestival 6-8%; sgucinid 5-6%.
Soil, gravelly loam.

The most important difference in the habitat is in water content,
the other factors being seed the same as given under the aspects
of the formation.

The following quadrats are also typical of the Bouteloua oligos-
tachya consocies, but represent this consocies as modified by the
occurrence within it of societies.

Bouteloua oligostachya ......... 47% Euphorbia stictospora............ 9
Artemisia frigida............... 45576. BOCRETA. DADROSE 5 oy aes sone 5 996

nogra coronopifolia............. ot: Abgpre albicailis e606. 9-36 425 2
Senecio oblanceolatus............ Total surface covered..........- 56%

Water content: vernal period se. aestival 46%; autumnal 3-4%. .
Soil, fine gravelly loam. :

A quadrat within a Gutierrezia Sarothrae society:

Bouteloua oligostachya..... 168 Eriogonum effusum.............. 5
Gutierrezia Sarothrae ...... 22 PMIGUETS, DRTIOONN <6 < ooo) ccs ches 5

eee 10 Malvastrum coccineum..........- ©

Water content: vernal period 4 5%; aestival 4-7%; autumnal 2-4%-
Soil, coarse gravelly loam mixed with lime.

The following quadrat will serve to illustrate a portion interme-
diate between the Bouteloua oligostachya consocies and the Muhlen-
bergia gracillima consocies.

Muhlenbergia gracillima .. 20 33% Boebera peIpea. soa es 36
Bouteloua oligostachya..... 24 12% Atheropogon curtipendulus.......- I
Sideranthus spinulosus..... 3 Aliishia linearis.) 2504 os I

vastrum coccineum..... 5 Echinocereus viridiflorus........-- I
Artemisia a i 2 To = surface covered nage eee et ye

1906] SHANTZ—VEGETATION OF THE MESA 43

Muhlenbergia gracillima consocies—This consocies covers the
greater part of the lower land, particularly that south of the Mesa.
The following quadrat is typical.

Muhlenbergia gracillima....... 46% ~ Boebera ‘papposi.. os 27. 25
Schedonnardus paniculatus...:; 6% Plantago Purshii.::..:...)2..7.0%4 9
Bouteloua oligostachya........ 1% » Senecio oblanceolatits..2). 205.5714 I
Artemisia frigida......... 19 1.5% Hedeoma nanes....5.1.433 ee I
Munroa SQUAFTOSA SS .). sev I Salvia: lancedlate.;.<22 05.2 ~ oe I
Gutierrezia Sarothrae..... 9 Euphorbia glyptosperma........... I
Picradeniopsis oppositifolia 3 otal surface covered........... 56%

Water content: vernal period 9-14%; aestival 7-9%; autumnal 5~-7%.
Soil, loam.

This consocies should also show Opuntia polyacantha, Stipa
Vaseyi, Argemone intermedia, Senecio spartioides, Verbena brac-
‘eosa, Atriplex argentea, Malvastrum coccineum, Astragalus cras-
sicarpus, A. bisulcatus, Sophora sericea, Quinculata lobata, Agropy-
ron occidentale, and many others.

In places M uhlenbergia gracillima is even more dominant
than in the quadrat given above, but as one passes to the higher
ground it gives way gradually to Bouteloua oligostachya.

Bouteloua hirsuta consocies—This consocies is best developed
on the crests and over the north portion of the Mesa. A quadrat
best illustrates the structure.

Bouteloua hirsuta.......... 95 17% Sideranthus spinulosus.......-.-.. 7
Artemisia frigida.......... 4% Oreocarya thyrsiflora...........--- 6

theropogon curtipendulus 1.5% lLacinaria punctata.............--- 4
Aristida longiseta..,....... 4 1% Gaura coctines......--°:--..--«-: 3
Andropogon scoparius...... .5% Euphorbia robusta.......-.------- 2
Bouteloua oligostachya.... . 3% necio MOR‘ CO isk os ts I
Thelesperma gracile 2... 16 tragalus Shortianus........------ I
Echinocereus viridiflorus 8 Pentstemon secundiflorus.......--- I
Senecio oblanceolatus...... 7 Total surface covered......--- '. 32%

Water content: vernal period 4.5-9%; aestival 2.5-4.5%; autumnal 1.5~
2.5%- Soil, coarse gravelly loam. This quadrat also illustrates the structure
of the vernal Euphorbia robusta society.

While Bouteloua hirsuta is predominant in this consocies, many
other species are important. Muhlenbergia gracillima is sometimes
Present; Aristida longiseta and Sitanion elymoides are sometimes

44 BOTANICAL GAZETTE [JULY

very important; Andropogon furcatus, Yucca glauca, Erigeron
pumilus, and E. canus are often present.

The physical conditions of this consocies are not essentially
different from those of the typical formation, except that the looser,
gravelly soil contains less water. It is the most xerophytic of all
the consocies. The following crest quadrat from the south part
of the Mesa also illustrates this consocies.

Bouteloua hirsuta......... 45°. 30%). Artemisia frigila 23 cee Pe 2
Bouteloua ee 34. 3% Senecio oblanceolatus............. 2
Aristida longiseta......... S 36% 5 Gaurd cottifies: -.cF a I
Atheropogon aes 30 <..5% © -Qreocarya: thyrsiflora: 00 Se 6. Tr
Gutierrezia Sarothrae..... 4 Echinocereus viridiflorus........... 1
Senecio spartioides........ 3 Lecanora subfusca ailophana®: cere 20
oo. angustifolius 3 Total a COVETEN es ok 8 23%

usts—a remnant of ie more primitive lichen form
eat content: vernal period 6-10%; aestival re ; autumnal 2.5-4%-
Soil, very coarse gravelly loam.
Societies of the Bouteloua hirsuta consocies: Pentstemon secundi-
florus society found on crests of the north or east part of the Mesa.
The following quadrat is typical:

Pentstemon. secundi- Evolvulus: pilosé..i.c630 6s 0: 2288 7
florus, (81 in bloom).....141 Sideranthus spinulosus..........-- 6
Artemisia frigida.......... 7% Echinocereus viridiflorus.........-- a

Bouteloua hirsuta.......... 65 pattie Was es ek ae 4
squerella montana (seed- Poruiaca oleracea... 5.6 cies I
ng oe a 40 Total surface covered.........-- 24%

Boebera

Water content: vernal period 4.5-9%; aestival 2. 5-4-5%; autumnal 1.57
2.5%. Soil, coarse gravelly loam.
Pentstemon angustijolius society—While Pentstemon angusti-
jolius does not form so dense an association as P. secundiflorus, the —
spikes are much larger, and it is therefore very prominent in certain —
areas. The following quadrat is typical:

Bouteloua hirsuta.......... 17 20% Artemisia canadensis..........--- 2
Pentstemon angustifolius... 14 (5%) Eriogonum Jamesii...........--- ta

Aristida longiseta.......... 1% Thelesperma gracile...........--- I ‘
Chrysopsis villosa.......... 8 Boehers. paptioes <: 55.44 3.06
Allionia linearis........... 5 Euphorbia stictos

Echinocereus viridiflorus.... 2
Gutierrezia Sarothrae 2

ee eee

otal surface covered

1906] SHANTZ—VEGETATION OF THE MESA 45

Water content: vernal period, 6-12%; aestival 4-6%; autumnal 2-4%.
Soil, coarse gravelly loam.

This society belongs to the vernal aspect and alternates markedly
with the above-mentioned society. So distinct is this alternation,
that on adjacent crests these societies may occur with no mixing
of the dominant species. It occupies the south and west crests of
the Mesa. The species is widely distributed over the top of the
Mesa, but seldom becomes dominant.

The following quadrat is taken from a community of Leucolene
ericoides:

Leucolene ericoides.............. 78 Eriogonum Jamesii......----+--- I
Bouteloua hirsuta................ 53 Psoralea tenuiflora........----+++ I
Aristida longiseta................ 13. Allionia linearis.........+--+++-> I
Eriogonum effusum.............. 3. Chenopodium leptophyllum ae aie I

The Agropyron occidentale consocies is not as well developed in
this region as elsewhere, but the following quadrat will show the
structure. This quadrat is taken from a community of Bouteloua
prostaia,

Bouteloua prostrata.............. 352. Salvia lanceolata.....-.--+---++**- 11
Agropyron occidentale............ 216 Polygonum aviculare....- S aicgee 10
Bouteloua Oligostachya........... 47 Picradeniopsis oppositifolia.....-- 9
Boebera an Se 123 Quincula lobata.....-----------° 4
Verbesina encelioides............. 108 Salsola Tragus.....----+--++7+*° 2
Gutierrezia Sarothrae............ 2

3 —
Water content: vernal period 13-17%; aestival 10-1 3%}; autumnal 8.5
10%, Soil, clay.

General discussion.

While the vegetation of the Mesa is typical of the high plains,
it does not show all of the structure that is at once apparent upon
the examination of a larger area. On the Great Plains lying east,
this formation is everywhere in evidence. By far the mest important
species is Bouteloua oligostachya—the dominant species of the forma-
tion. That part of the formation which is mest typical is the B.
oligostachya consocies. This consocies is much more closed and
pute on the great level plateau farther east than it is near the moun-
‘tains. It often covers as much as 60-70 per cent. of the Saag
and is associated with very few primary or secondary species. 41

46 BOTANICAL GAZETTE [yoy

>

the clay flats it often gives way to the M uhlenbergia gracillima or
A gropyron occidentale consocies, and in passing to sandy or gravelly
ridges it is often dominated by the Bouteloua hirsuta, Andropogon
scoparius, or Koeleria cristata consocies. Even on the slopes of
more level sandy areas it alternates with the Calamovilja longt
jolia consocies, and at times with the Andropogon furcatus con-
socies. Although these consocies dominate immense areas, they
are not to be regarded as constituting distinct formations. Boule
loua oligostacyha is prominent everywhere and these are merely
modifications of the Bouteloua formation, or in other words, con
socies of this formation.

To discuss each aspect of this formation would take too much
space, and some idea may be obtained by referring to the lists given
earlier in this paper.

There is a rather marked zonation in regions characterized by
rolling or uneven ground. The hills and ridges are occupied by
Bouteloua hirsuta. Jn this habitat there is a rather marked alternation
with other consocies. Andropogon scoparius often becomes domi-
nant, as does also Koeleria cristata. Here are also found a numbet
of prominent societies, among which the most xerophytic is the
Selaginella densa society. S porobulus crypiandrus and Stipa comata
may also become prominent.

Occupying the sides cf the slopes and the level expanses is the
extensive Bouteloua oligostachya consocies. Alternating with this 1s
found the Andropogon jurcatus and the Calamovilja longifolia con-
socies. This alternation is often very marked, the consocies remain
ing distinct from each other.

It is here that the most important societies of the formation are

found, many of which extend for many miles without interruption-

Among the most prominent of these societies is the Grindelia squar —

rosa society, which extends for many miles east of Limon, Col.
and occurs over less extensive areas in many other parts of the forma
tion. The Schedonnardus paniculatus so
Col., and Goodland, Kans.

of the most prominent so

ciety occurs throughout the |
formation and in many places is very extensive. Between Burlington, —
» the scciety extends for many miles: —
Thelesperma intermedium also occurs in this consocies. It is one —

a Ee ee a

cieties in the formation and is especially e

1906} sHANTZ—VEGETATION OF THE MESA 47

well developed just east of Colorado Springs. The Gutierrezia
Sarothrae society occurs more often near the mountains and bluffs.
Artemisia canadensis is also important in similar locations, while
A. dracunculoides is most abundant farther out on the plains. Opun-
tia polyacantha in most places merely forms small communities or
families, but in many places on the plains these become associated
into an extensive society. This is especially true east and south
of Fountain, Col. O. arborescens is also found in this region and
extends northward to within a few miles of Colorado Springs.

Carex stenophylla, Senecio oblanceolatus, Sophora sericea, Astra-
galus Drummondii, Oreocarya suffruticosa, Eriogonum annuum,
Chrysopsis villosa, Boebera papposa, and Plantago Purshii each
form extensive societies in this consocies. The following s<cieties
are not so extensive, but on account of the prominence of the plants
characterizing them they are very noticeable: Ipomoea leptophylla,
Yucca glauca, Lupinus argenteus, Carduus plattensis, Eriogonum
effusum, Chrysothamnus graveolens, Senecio spartioides, Pentstemon
angustijolius, P. secundiflorus, and Astragalus bisulcatus.

Passing now to the lowlands, the Bouteloua oligostachya ccn-
socies is found with very few primary or secondary species, and
usually alternating with the Muhlenbergia gracillima and the Agro-
byron occidentale consocies. These consocies are sometimes mixed,
but as a rule remain distinct. A gropyron occidentale, a tall slender
8tass, is usually not associated with many other species, and the
mats of Muhlenbergia gracillima also leave little space for the develop-
ment of any but a few of the clay-loving annuals. Astragalus
bisulcatus, Sophora sericea, Boebera papposa, Plantago Purshii, and
Atriplex argentea are among the most important secondary species
of these consocies.

UNIVERSITY oF Missouri,
Columbia, Mo.

CONTRIBUTIONS FROM THE ROCKY MOUNTAIN HER-
BARIUM. VII.

AVEN NELSON.

Cypripedium Knightae, n. sp.—Stem short, 3-7°™ high, sparsely
and coarsely villous, bearing a single pair of nearly opposite leaves
at its summit: leaves oval, generally rounded and obtuse, thickist
4-7°™" long: peduncle glandular-viscid, 3-10°™ long, usually nakec.
rarely with a lanceolate bract near the middle: floral bracts rathe: |
large, elliptic-lanceolate: flowers 2 or 3 in a cluster, dark-purple i.
lower sepals united nearly to the tip, ovate-lanceolate, the two together
no broader than the other sepal: petals similar, a little broader
than the sepals: lip 1o-12™™ long, somewhat shorter than the
sepals and petals, the deeply infolded free margin deep-purple,
the lower part of the sac ochroleucous or greenish-yellow: sterile _

anther elliptic, obtuse, much shorter and smaller than the large
conspicuous stigma.

q
.

xy ? ety (ul

SD ee Pee

is species, in so far as it has been collected, has seemingly passed as C-
jasciculatum Kellogg, Wats. Proc. Am. Acad. 17: 380. That is a very different
thing, as may be seen by referring to the original description, or to Howells’s
Fl. N. W. Am. 632. It is, moreover, of a quite different geographical range. I
have great pleasure in naming this fine species for Miss Harriet Knight, whose
sympathetic interest in all nature and whose intelligent activity in the educa-
tional work of Wyoming is greatly appreciated.

Collections at hand: Miss Knight, Medicine Bow Mts., Wyo., at Coopel —
Hill, July 1905 (type); L. N. Goodding, no. 1201, Uinta Mts., Utah (Dyer Mine), —

June 30, 1902; G. E. Osterhout, Estes Park, Colo., July 1897; and Encamp: |
ment Creek, Sept. 1897. 4

yo

Montia Viae, n. sp. —Annual, with fibrous roots: stems and
petioles weak, suberect, 10-1 5°" high: leaves delicately thin, pale-
green; the radical several, slender-petioled, the short blades from
linear to oval, acute; the single pair of cauline connate and forming
a circular or slightly irregular involucral disk 1o-20™™ broad: raceme
peduncled, with a pair of green bracts at the base of the lower pedr
cels: flowers very small, several: sepals broadly oval, even in fruit

less than 2™™ long: petals 5, spatulate, barely equalling the sepals,
Botanical Gazette, vol. 42] [48

Se Se oe ee

1906] NELSON—ROCKY MOUNTAIN PLANTS 49

very delicate, apparently often wholly wanting: stamens 5, very
short: ovule solitary; the seed smail, oval, slightly compressed
and subcarinate, minutely but distinctly papillose-roughened and
with a waxy conspicuous strophiole.

Most nearly related but very distinct from M. perjoliata (Donn.) Howell,
Erythea 1:38, a plant of the Pacific states. Possibly all of the central Rocky
Mountain specimens named M. perfoliata belong here. The type specimens
were collected by the Misses Dorothy Reed and Vie Willits, June, 1905. Miss
Willits, in whose honor the plant is named, later secured an abundance of fruiting
specimens. Type locality, shady muddy banks, Big Horn, Sheridan Co., Wyo-
ming.

Lesquerella latifolia, n. sp.—/erennial, silvered witha fine
lepidote stellate pubescence throughout: stems numerous, from
among the crowded rosulate crown leaves, decumbent at base, spigad-
ing, 5-15°™ jong: radical leaves suborbicular, oval, or rhombic,

~ sometimes broader than long, from 1-3°™ in diameter; the petioles,

slender, often much longer than the blade; cauline leaves from
broadly obovate to spatulate, all cuneately tapering into a slender
petiole: racemes of showy bright-yellow flowers dense, elongating
in fruit: petals spatulate, g-10™™ long, twice as long as the oblong
sepals: siliques elliptic, very perceptibly stipitate, 5-6™™ long, erect
on §-shaped pedicels of about the same length; style slender, 3-4"™
long; cells about 5-ovuled.

This is based upon Mr. L. N. Goodding’s no. 625, from Karshaw, Meadow
Valley Wash, southern Nevada, Apr. 26, 1902. It has been distributed as L.
montana, a species from which it is as far removed as t> characters as it is geo-
graphically. .

Lesquerella Lunellii, n. sp.—Pale green, modetately and minutely
stellate-pubescent throughout: caudex a mere crown surmounting
the slender tap root: stems few to several, ascending or assurgent,
very slender (almost filiform), 3-15°™ long (including the raceme):
leaves narrowly linear-oblanceolate, 1-2°™ long; the lower tapering
into the slender petioles: raceme at length open and long for the
plant: sepals purplish-green, linear-oblong, subacute, 4-5™™ long:
the spatulate-obovate petals nearly twice as long, the upper half
of the blade a fine purple, shading into the yellow of the lower half
and the claw: silique globose, 4-5™™ in diameter; the slender

50 BOT 1NICAL GAZETTE [yoy

style as long and the gscending or oftea recurved pedicel usually
distinctly longer.

Dr. J. Lunell, of Leeds, N. D., an enthusiastic student of the northwest |
flora, communicated the specimens tome. I have pleasure in naming the species.
in his honor. He writes: ‘‘It grows on high barren hills among rocks. Its
petals are broadly purple-tipped, and the base a bright-yellow.” Collected
at Butte, Benson Co., N. D., June 13, 1905.

Lepidium Zionis, n. sp.—Glabrous perennial, 1~24™ high: stems
several from the crown of a rather thick semi-fleshy vertical root —
decumbent at base but assurgert-erect, each ély branchel”
at sumnut: all the leaves erect, quite entire, thick or subcoriaceous,
acute or apiculate; radical leaves oblong, 2-3°™ long, tapering 10
a sleader petiole as long as the blade; cauline leaves very numerous,
alrsost imbricated, linear-lanceolate, 1 5-25*"™ long: racemes short,

. cfowded: sepals elliptic, scarious margined, half as long as the |
obovate-cuneate white rather conspicuous petals: stanicnis 2: silique |
ovate or elliptic, somewhat keeled, glabrous, not emarginate; the |
style and small stigma one-fourth as long. :

This quite unusual species rests upon but one collection at present, M. E.
Jones’ no. 5411, Richfield, Utah, June x 3, 1894.

Cardamine incana (Gray), n. n.—C. cordifolia incana Gray, Jones”
in Proc. Cal. Acad. Sci. dT. §:620. 1895; C. cardiophylla Rydb.
Bull. Torr. Bot. Club 28: 280. Igor; not C. cardiophylla Greene,
Man. Bot. 19. 1894. -

Euphorbia Aliceae, n. sp.—Perennial from slender horizontal _
rootstocks, glabrous or slightly puberulent, 10-1 5°™ high: stem
branching from the base, the branches spreading-decumbent: leaves
narrowly oblanceolate, short-petioled, sharply serrate, opposite,
more crowded toward the terminal clustered involucres: involucres _
nearly sessile, smail, turbinate, somewhat fimbriate-margined; the :

glands about 4, small, ipi

a ie ee nS

with a caruncle, slightly tuberculate, ashy.

Known as yet only from Hartville, Wyoming, no. 549, collected July 15
1894. Nametin honor of Mrs. Celia Alice N. elson, whose industry as a collector
is responsible for thousands of specimens found in the leading herbaria, although
her name has never appeared on a plant label.

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ve saat ait bes Ee ee Z

1906] ' NELSON—ROCKY MOUNTAIN PLANTS 51

Delphinium Cockerelli, n. sp.—Tawny-pubescent on stems and
in the inflorescence, densely and viscidly so above; the leaves obscurely
pubescent: stems nearly simple or bushy-branched, 6-12 high:
leaves large, often 12-18°™ in diameter, the veins strikingly super-
ficial, about 5-cleft or parted into broadly oblong or oblong-cuneate
divisions, these merely coarsely toothed or incised above the middle:
racemes often several, open, with rather long peduncles and pedicels
and few flowers (5-10) : flowers bright-purple, large (3-4°™ long) : sepals
oblong-lanceolate, acute, about as long as the thick curved spur:
petals small; the upper yellowish-white, concealed within the upper
sepal; the lower purple, with suborbicular blade, cleft and sparsely
hirsute ciliate.

An unusually handsome species, with somewhat the aspect of A. subalpinum
(Gray) A. Nels. Bull. Torr. Bot. Club 27:263. The type was collected by
Mrs. O. St. John, no. go, Baldy Mts., Elizabethtown, N. M., Oct., 1898. It
was communicated to me by Professor Cockerell, who called my attention to
some of its distinguishing characters. C.F. Baker’s no. 325, near Pagosa Peak,

Colo., is also quite typical.

Aconitum lutescens, n. sp.—Root’ small, fusiform-tuberous:
stems slender, simple, erect, only 3-6 high, glabrous nearly to the
inflorescence: leaves 3-5°™ broad; the 5 broadly cuneate divisions
deeply and incisely toothed above the middle: raceme narrow, long
for the plant, rather open; the flowers a pure cream-color, becoming
nearly white or pinkish in drying; rachis and pedicels softly
hirsute-ciliate with straight viscid hairs standing out at right angles.

This Aconitum with its fine cream-colored flowers may best stand as a species.
Collections of it are as follows: Aven N elson, no. 1521 (type), Cummins, Wyo.,
July 1895; T. D. A. Cockerell, no. 87, Beulah, N. M., 1898; W. S. Cooper, no.
274, Estes Park, Colo., July 1904.

Anemone zephyra, n. sp.—Green but sparsely long-pilose: stems
one or more from the thick erect caudex, 7-15°™ high, rather stout:
basal leaves petioled, ternate, the broad petiolulate segments in
turn deeply incised into linear-oblong lobes; involucral leaves sessile,
with linear-oblong lobes: flowers large, 2-3°™ broad, lemon-yellow
or ochroleucous, usually solitary and rather long-pedunculate, some-
times umbellately 2-4-flowered: achenes large, glabrous, obovate,
tapering to a stipe-like base, tipped with the short hooked style.

52 BOTANICAL GAZETTE [JULY

There seems to be no good reason for continuing the name A. marcissiflora
for this plant of the central Rocky Mountains. That Arctic species is white:
flowered, the flowers very closely umbelled in the involucre, and the leaves ar
cleft into many more lobes than ours. The proposed species probably include
all the specimens from the Rocky Mountains of the United States distribute
as A. narcissiflora or A. albomerus (ined.).

Anemone stylosa, n. sp.—Low from a thickened simple ot
branched caudex densely covered with the dead sheathing petioles:
basal leaves pale green, glabrous, biternate, segments 3-parted,
again incised into linear-lanceolate acute lobes; involucral leaves
short-petioled, otherwise quite similar: stems and petioles sparsely
long-pilose, the hairs spreading or refracted: sepals oval or oblong,
purplish red or greenish red: achenes pubescent, with rather long
straight glabrous persistent styles hooked at the tip.

This I take it is the plant referred to A. tetonensis in Syn. Fl. N. A. 1:10
As yet reported only from type locality, Fish Lake, Utah, M. E. Jones, no
5763 and 5764, Aug. 7, 1894.

Clematis plattensis, n. sp.—Stems clustered on the crown of !
thick woody root, 12-18°™ high, terminated by the single stoul
peduncle of nearly equal length in fruit, sparsely short-villous: basal
leaves small, scale-like and entire: foliage proper of about 3 pails
of nearly simply pinnate short- petioled leaves ; pinnae 7-9, the
lowest pair sometimes ternate, all distinctly petiolulate (petiolule
3-10™™ long) and long-villous: achenes long-tailed, hairy-plumose:
flowers not known, presumably much like those of C. Douglasit.

Type from the North Platte Cafion, in eastern Wyoming, Aven Nelson,
no. 8355, July 2, 1901.

Ranunculus Jovis A. Nels. Bull. Torr. Bot. Club 2'7: 201. 1900:

This it turns out is R. digitatus Hook. , an untenable name, as it is antedated
by R. digitatus Willd. R. Jovis will therefore have to stand for Hooker’s plant

Ranunculus platyphyllus (Gray), n. n.—R. orthorhynchus platy |

phyllus Gray, Proc. Am. Acad. 21:377. 1886; R. maximus Greené
Bull. Torr. Bot. Club 14:118. 1887.

rejected.

Saxifraga oregonensis (Raf.) n. n.—Diminutive perennials fro™ )

|

a slender caudex: stems simple, 3-8°™ high, glandular-pubescent the

There seems to be no good reason why Dr. Gray’s name should have bee! _

i

Te

1906] NELSON—ROCKY MOUNTAIN PLANTS 53

leaves small, mostly basal, oblong-spatulate, minutely hispid-ciliate:
flowers few, in a crowded glomerule at summit: calyx minutely
glandular-pubescent, its whole tube adnate to the carpels: petals
broadly obovate-cuneate, truncately rounded at summit, twice as
long as the calyx lobes, distinctly divergently 3—-nerved: the distended
subglobose calyx-tube papillcse-rugose from the pressure upon it by
the numerous brown seeds within.

This is the rare and troublesome little alpine plant of the middle Rocky Moun-
tains which has been referred to S. adscendens L., an arctic plant from which it

Seems to be distinct. The other names which it has also borne are S. petraea

L. and S. controversa Sternb., both of which seem to refer to S. adscendens ie
and are furthermore both encumbered by synonyms through their application
to other very distinct species. Therefore it seems best to take up Rafinesque’s

name, under Ponista (P. oregonensis Raf. Fl. Tellur. 2:66.1836), as there can

be no doubt as to its application to our plants.

SAXIFRAGA SUBAPETALA normalis, n. var.—Very similar to the

Species, but petals evident, elliptic-spatulate, as long as the calyx-

lobes: as in the species the carpels are immersed in a crest-margined
disk which persists at the middle of the mature carpels as an
undulate ridge.

For the description of the species see Erythea 7:169. 1899. This has been

distributed by various collectors either as S. integrifolia or as S. Sierrae, from

both of which it is quite distinct.

Parthenocissus laciniata (Planch.), n. comb.—P. quinquejolia

Jaciniata Planch. in DC. Mon. Phan. 5:449. 1887; P. vitacea

(Knerr) A. S. Hitch., Sp. Fl. Man. 26. 1894.

Prunus ignotus, n. sp.—Shrubby or possibly becoming tree-like:
branches slender, none of them becoming indurated or thorny:
leaves glabrous from the first, simply and sharply serrate: flowers
white, appearing with or after the leaves, solitary or 2-3 in a cluster:

‘calyx turbinate; its lobes entire, glabrous within and nearly so with-

Out: petals obovate: fruit not known.

It is a little singular that no one has reported this in fruit, but the fine speci-
mens distributed by Prof. C. S. Crandall, as P. pennsylvanica, from the banks

“of the Cache la Poudre, near Ft. Collins, Colo., May 1897, cannot well be ignored.

Philadelphus intermedius, n. sp.—A low branching shrub with

‘dark green glabrous aspect: leaves short petiolate or subsessile,

54 BOTANICAL GAZETTE [yory

broadly oval to ovate, rounded at base and either subacute or obtuse
at apex, entire, glabrous or with some scattering ciliate hairs closely
ciliate on the margins with short incurved hairs, 15-25™™ long:
flowers medium size, a 3-flowered cyme from the terminal pair oi
leaves, a pair of flowers in the next pair of leaves, and sometimes
another pair in the axils of the next lower pair of leaves—thus all
the flowers except the terminal one are foliose-bracted: calyx glabrous,
its lobes finely pubescent within: petals oval, about 12™™ long:
stamens 30 or more: styles united for two-thirds of their length, the
free portion as long as the abruptly enlarged stigmatic portion.

This is most nearly allied to P. Lewisii Pursh, from which its smaller siz,
smaller leaves, smaller flowers, and peculiar stigmas distinguish it. In P. Lew
isii the styles are united throughout, the stigmatic portion as long as the style
proper, the stigmatic line being broad and capping the summit of the stigms
and then extending down to the styles in a narrowing line. P. intermedius
seems to be a connecting species between the desert species of Utah and Colorade
and those larger forms of the humid northwest.

Philadelphus nitidus, n. sp.—Slenderly and divaricately branched:
leaves rather few, shining and with glaucous hue on both sides,
nearly glabrous above, minutely appressed strigose below, mostly
narrowly lance-oblong, subacute at both ends, very short petioled,
1-2°" long: flowers generally solitary at the ends of the branchlets:
calyx cleft below the middle, hirsute on the outside, soft pubescent
on the inside of the lobes: petals elliptic, entire, 8-ro™™ long, twice
as long as the calyx lobes: stamens 30-40: styles distinct down t
the ovary: stigmas short, slightly geniculate at junction with filament. _

__ The following collections of this species are at hand: H.N. Wheeler, no. 425
(type), Sapinero, Colo., 1898; C. F. Baker, no. 266, Black Cafion, Colo., June
27, 1901; M. E. Jones, no. 6303, Belknap, Utah, June 28, 1899. ’

LARAMIE, WyomInc. ;

i a lg 7 ee

BRIEFER- ARTICLES

ANTHOCEROS AND ITS NOSTOC COLONIES.

THE association of the liverwort Anthoceros with the blue-green alga,
Nostoc, has long been known and has been studied with considerable
care. The significance and value of this association have been speculated
upon; but, as far as I know, no experiments on the subject have been
reported. The anatomical relations of the two associates have been
studied and described, but I do not know that cultures of Anthoceros
from the spore on sterilized soil have been attempted. I shall here describe
both the culture of Anthoceros, and, at the risk of some repetition of facts
already recorded by others, the anatomical relations of the Nostoc to the
surrounding tissue.

Anthoceros fusijormis Aust., and A. Pearsoni M. A. Howe fruit here
abundantly in May. Their spores can then be collected almost or quite
unmixed and free from the spores of other small plants, and may be kept
air-dry for months. The dry season ordinarily lasts from mid-May to
October, and during this time usually no rain falls. ‘The spores germinate
out of doors soon after the first abundant rain has thoroughy moistened the
soil to a depth of several inches. The natural “‘resting-period” for the
spores is, therefore, four or five months long, but the spores retain their
vitality much longer. They may also be made to germinate in much
shorter time. The ‘“‘resting-period” seems to be, therefore, a matter of
natural conditions rather than of transmitted habit.

The soil on which I grew plants from the spore was brought into the
laboratory from the bank on which these plants, along with other small
archegoniates, grow abundantly during each rainy season. After thor-
ough air-drying, the soil was freed from pebbles, pulverized in a mortar,
and put to a depth of a centimeter or slightly more in crystallizing dishes
of thin white glass. These dishes were about 8°™ in diameter, 3.5°™ in
depth, and were covered by the lids or bottoms of Petri dishes. These
covers do not fit tightly; at the same time that they exclude dust and
maintain the moisture of the air, they permit fair ventilation. The soil
Was invariably moistened from the beginning with boiled distilled water, for

Wished to avoid any accumulations of salts in these undrained cultures
from using our hard tap-water. These covered dishes were now divided
55] [Botanical Gazette, vol. 24

56 BOTANICAL GAZETTE [yuLy

into two lots of equal number, one lot being put aside in the dark for a
few days and the other steam-sterilized for two or three hours on three :
successive days. This sterilization proved thorough so far as blue-green
algae are concerned, since none developed in the dishes. A certain amount
of infection is unavoidable, and a few cultures in each lot had to be thrown
away because of the development of some ‘‘damping-off” fungus. But _
on the whole the plants in my cultures have done quite as well as those _
out of doors. During the growing season now ending they did better than

those out of doors, because November and December were cold and dry.

Eleven or twelve weeks after sowing, the small plants already beat
archegonia and antheridia when the cultures are kept under suitable con-
ditions of illumination. Cultures kept too dark will contain few if any
fruiting plants, though the plants may be normally large. From this
fact, though I have not attempted to support this view by further investi-
gation, one may infer that light acts as a stimulus to the development of
the reproductive organs as V6CcHTING! and KiEBs? have shown to be the
case in certain flowering plants and fresh-water algae.

On comparing the young plants on sterilized and on unsterilized soil
the greater size and more robust appearance of the plants on sterilized soil
is evident. The plants on sterilized soil contained no Nostoc colonies.
The plants on unsterilized soil contained Nostoc colonies, few of them
bore reproductive organs, and they appeared less thrifty. But the young
Anthoceros plants on unsterilized soil were obliged to compete not only
with .each other but with several other sorts also. Without attempting
an exhaustive list of these other plants I may record the presence, in the |
cultures, of prothalli of Gymnogramme tiriangularis, fronds of Fimbri- —
aria Calijornica, two or three small mosses, both protonemal and adult, —
some green algae (especially a small Vaucheria), some blue-green algae i :
(Nostoc, Oscillatoria, Anabaena), chickweed, and grass. Besides these,
which started from spores, seeds, or other resting stages, there were small |
plants which had held over the dry season as CAMPBELLS has described, |
fern prothalli and plants of Fimbriaria and Anthoceros. %

Where young plants of Anthoceros have to compete in small cultures —
with such a number of individuals and of kinds of already fairly estab-
lished plants, it is natural to assume that this amount of competition may

Go ala ie

* VécuTING, H., Ueber den Einfluss des Lichtes auf die Gestaltung und An lage
der Bliithen. Jahrb. Wiss. Bot. 25: 149. 1893. :

2 Kiess, G., Die ‘Bedingungen der Fortpflanzung bei einigen Algen und Pilzen. Hi :
Jena, 1896.

3 CAMPBELL, D. H., Resistance of drought by liverworts. Torreya 4:81. 1904+

ta ae

7 cee &

1906] BRIEFER ARTICLES 57

have much to do with their less thrifty appearance. However, the presence
of Nostoc colonies on the soil does not necessarily imply the infection of
all Anthoceros plants near them. As a matter of fact, a good many
Anthoceros plants free from Nostoc can be found on unsterilized soil.
These look better than those beside them containing Nostoc colonies, and

' as well as those in the dishes of sterilized soil.

Where cultures receive light mainly from the side, as is generally the
case in a laboratory, Anthoceros plants, like fern-prothalli and the thalli
of Fimbriaria, turn up from the surface of the soil, presenting their normally
upper surface toward the window and bearing rhizoids on the shaded
side. These plants necessarily contain fewer Nostoc colonies than those
remaining flat on the soil, for the younger and elevated parts are less acces-
sible to Nostoc filaments. Comparisons of older cultures than those just
described shows that Anthoceros plants containing only one or two algal
colonies are nearly or quite as thrifty as those with none, and are decidedly
more vigorous than those with many.

PRANTL‘ attributed an advantage to Anthoceros from its association
with Nostoc, on the ground that Nostoc might fix the free nitrogen of the
air and contribute its products to the liverwort, but the weight of evidence
seems now to be against the assumption that blue-green algae by and of
themselves add at all to the combined nitrogen in the soil,5 whatever the
results of their association with N-fixing soil bacteria may be. The fact
that, in my cultures at least, Anthoceros does better when free from Nostoc,
removes all ground for PRANTL’s claimed advantage from the association
so common in nature.

On the other hand JANczEwskt’s designation of the Nostoc colonies
as parasitic® is not logically justified by my cultures or by the luxuriance
in growth and by the fertility of these two species of Anthoceros in this
region in ordinarily good seasons. Last year they throve as I never saw
them before. This season has been by no means so favorable, dry weather
having come long before the plants, held back by the cold and dryness of
November and December, could ripen their spores in large numbers.
All T feel inclined to say is that Nostoc certainly does not benefit An-
thoceros, which in fact does better without it.

It is a matter of common observation that many blue-green algae

+Pranti, K., Die Assimilation freien Stickstoffs und der Parasitismus von
Nostoc. Hedwigia 28:135. 1889.

‘ Prerrer, W., Pflanzenphysiologie, 2te Auflage, 1:386-7, 393. 1897.

° JANCZEWsKI, A. DE, Vergleichende Untersuchungen iiber die Entwickelungsge-
schichte des Archegoniums. Bot. Zeit. 377 f. 1872.

58 BOTANICAL GAZETTE (JULY:

thrive best where there are considerable quantities of organic matter.” It.

is conceivable that Nostoc profits from intimate association with green

plants, but to prove the parasitic nature of such association is very diff-

cult. I could not detect that the Nostoc cells, filaments, and colonies
within the thallus of Anthoceros appear healthier, or larger, or grow more
rapidly, than those on the moist earth near by. The cells of this and
many other blue-green algae are so small and the organs of the cell s0
slightly differentiated that differences between cells are by no meats
noticeable. From the evidence at hand it is equally unsafe to say that
Nostoc is or is not parasitic in Anthoceros. 2

Passing now to anatomical considerations, PRANTL’ asserts that the
characteristic development of the thallus cavities and the formation of
internal hairs follows the entrance of Nostoc filaments only, not of any
other small plants. The manner of infection I will not go into, for it
has been repeatedly described.2 The invading filament, if it survive,
gives rise to a colony, spheroidal in form and enclosed in gelatinous mattef
which increases with the growth of the colony. Mechanical pressure,
increasing with the growth of the colony and with the amount of water:
absorbed, is brought to bear against the surrounding cells of the thallus
enlarging the cavity which the Nostoc filament entered through one of
the slime-slits on the surface. Another effect of the increasing pressute
is the compacting of the immediately surrounding tissue. But becaus¢
the Nostoc colony is not homogeneous, being in part cells and in part the
gelatinous product of these cells, the pressure is not equal over all parts
of the surface. The gelatinous matter between the filaments is softer and

more readily penetrated or displaced than the filaments themselves. Ii

small thallus cells lie opposite to and in contact with these gelatinous parts
of a colony, they will necessarily be pushed forward by their neighbors.
As has long been known, chains of cells, constituting the internal hairs
above mentioned, do grow into the colonies and among the filaments of

Nostoc. Other organisms, though they may enter the body of the liver

wort, either do not exert any pressure at all, being smaller than the cavities

they occupy, or form such compact masses that there is no chance for the _

surrounding cells to grow out as chains. :
From this consideration of the structure and mechanics of the Nostot
colony, we are led to see the fallacy of PRanTL’s argument that, becaust

7 See for example KircHner, O., Schizophyceae in Engler & Prantl’s Natiir
898.

liche Pflanzenfamilien. I. 3248.3
8 PRANTL, K.., loc. cit.
9 CAMPBELL, D. H., Mosses and Ferns, Ed. 2,128. New York, 1905.

ll

ee

1906] BRIEFER ARTICLES 59

cavities and hairs do not develop in the familiar way except where Nostoc
colonies are, the liverwort must profit by such associates. It is simply a
matter of mechanics. Where the resistance is less than growth can over-
come (and this is the case between the Nostoc filaments in the gelatinous
mass), the liverwort cells will grow out, forming short hairs. The growing
and swelling colony as a whole will enlarge the cavity in which it lies.
There are other intercellular spaces throughout the thallus, but these are
not enlarged because not occupied. There is no conceivable advantage
in their enlargement.—GEorcE J. Petrce, Stanford University, Cali-
jornia.

DISTRIBUTION AND HABITS OF SOME COMMON OAKS.

SINCE writing the paper under this title, which appeared in the June
number of this journal, I have been in Milwaukee and had the opportunity
of examining the oaks in two herbaria, probably representative of any that
may be found there. In the Public Museum were two specimens labeled
Quercus palustris Du Roi. One had an acorn, and as far as determinable
-by this and the leaf-characters, was Q. ellipsoidalis; it is certainly not what
it is labeled. The other was without fruit, and was doubtless the same
species. In the herbarium of Dr. Lewis SHERMAN, one of the older
residents of Milwaukee and an acquaintance of Dr. LAPHAM, was a speci-
men labeled as above. It had an acorn cup but no nuts. This showed
at least that it was not Q. palustris. All the evidence tends to the con-
clusion that the real pin oak does not occur in the region from which
these specimens were taken.—E. J. Hut, Chicago.

CURRENT LITERATURE.
BOOK REVIEWS. -
Evolution.

A COMPREHENSIVE account of the subject of evolution is at present a matter
of considerable importance, but at the same time must be one of unusual diffi-
culty because of the great activity incited by the work of DE Vries and others”
who have within the last few years undertaken the study of variation, adaptation, —
and heredity by experimental methods. Dr. J. P. Lorsyt has undertaken this
most difficult task by the publication of a volume of lectures upon theories of
descent with special reference to the botanical side of the question. He follows
the method not infrequent among older writers but rare among writers of recent
Scientific works, of beginning at the beginning. He first considers the nature
of knowledge, and the supposed conflict between science and religion, pointing
out that evolution will not explain everything, and that there is no conflict between
religion and science éxcept as either or both attempt to explain dogmatically
the unexplainable. Both science and religion come to the same’ conclusion
when traced to their limit, namely, that there is a fundamental mystery incapable
of investigation because none of the possible alternatives is even conceivable to —
the human mind.

as dominance and blending, atavism, kryptomery, pleiotypy, half races, etc., a :
and one to the inheritance of acquired characters. me

* Lotsy, J. P., Vorlesungen iiber Descendenztheorien mit besonderet Beriick-
sichtigung der botanischen Seite der F rage, gehalten an der Reichsuniversitat 24
Leiden. Erster Teil. 8vo. pp. xii+ 384. pls. 2. figs. 124. Jena: Gustav Fischer.
1906. M 8; geb. M 9.

60

1906] CURRENT LITERATURE 61

Discontinuous variation and mutation are treated in three lectures, and the
six remaining lectures trace the history of the evolution idea from ARISTOTLE to
Darwin, the last lecture being devoted to the life of the latter.

A treatise on contemporaneous science is fraught with the same difficulties
as attend the writing of contemporaneous history. A just estimate of the impor-
tance of the latest developments in either case only becomes possible in the light
of subsequent development, and consequently a book of this kind might be
expected to have a very evanescent value. Lorsy has avoided very much of
this by taking a judicial attitude and treating his subject historically. He has
depended to a very large extent upon quotations from the various scientists whose
views or results he has presented, and this gives the reader something of the
unpleasant sensation always given by a so-called “digest;” but his choice of
quotations is good and his own language is simple and direct, and therefore
easily followed. -

A second volume is promised, in which is to be indicated the work still to
be done, and this will be awaited with much interest, for it will be here that we
may hope to gain more of the personality of the author. The present volume
is exceptionally impersonal, and both gains and loses by this fact. If the second
volume takes on the strength and virility of personal enthusiasm which incites
to investigation, the lack of such qualities in this first volume may not be looked
upon asa disadvantage. But even if it should indicate in the same dispassionate
manner that characterizes this book, the problems awaiting solution, he will
deserve the gratitude of every biologist. While this book can not be said to jill
the need that called it forth, it is gratifying that the first attempt at filling it is
so excellent. As the first comprehensive work dealing with the more recent
phases of evolutionary study it should at once gain a deservedly large circula-
tion.—Grorce H. SHULL.

Chemistry of plants.

THE second volume of CzAPEK’s Biochemie der Pflanzen is a huge one,’
and deepens the impression made by the first volume of the immense labor
which sucha compilation represents, and the equally immense service which the
author has rendered to science in its preparation. For knowledge of the chem-
istry of plants has lagged far behind that of animals, which, under the stimulus
of human relations through medicine, has been under constant investigation
by many students.

his volume is devoted to (x) the proteids and their metabolism in various
plants (bacteria and fungi, mosses, algae, seeds, buds, leaves, roots, pollen
grains) including the formation, absorption, and regeneration of proteids by
various parts and under various conditions; (2) the nitrogenous end produ:
of metabolism, including purin bases, glucosides yielding HCN, and alkaloids;

aay
? CzaPEK, F., Biochemie der Pflanzen. Zweiter Band. 8vo. pp- xii +1027.
Jena: Gustav Fischer. 1905. M 25. 7

62 BOTANICAL GAZETTE [JULY

(3) respiration and its products; (4) coloring matters other than chlorophyll
and its associates; (5) mineral constituents; and (6) substances produced by
stimulation. At the close is an appendix of 21 pages with many supplementary
notes and corrections, bringing the data down to June 1905. A complete index
renders available the rich store of information summarized in the text, and gives
ee a clue to the literature of any substance or the chemistry of any group of
plants.

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and well-printed letter-press at the price.—C, R. B,
Sylloge Fungorum.—Volume XVIII, Part VII of the Supplement of that

monumental work of taxonomic mycology, Saccardo’s Sylloge Fungorum, has — :

eit wdwes. Myxomycetae, Myxobacteriaceae, and Deuteromycetae. The last
group, which constitutes the Fungi I mperfecti of the older volumes, occupies fully

me Grout, A. J., Mosses with hand-lens and microscope, a non-technical hand-
i = the pa rae mosses of the northeastern United States. Part Il.

+ OVO. pp. 167-246. pls. 36-55. jigs. 79-133. B thor,
360 Lenox Road. 1906. $1.25. if ete SE: —— _

ay

1906] CURRENT LITERATURE 63

two-thirds of the present volume. The work concludes with the usual ‘reper-
torium,” index of species, and a complete index of genera in all volumes. The
generic index is printed on differently colored paper. Some suggestions regard-
ing the diagnosis and nomenclature of species printed in the first pages of the
volume aim to bring about some uniformity in the publication of species. As
these rules have been published in several journals, it is unnecessary to repeat
them here-—H. HassELBrinc.

A book for young gardeners.—A booklet prepared by H. D. Hemenway,
the director of the School of Horticulture at Hartford, Conn., will prove helpful
to those interested in home and school gardens. Aside from simple discussion
of the objects and benefits of tillage, the preparation of the soil, and planting
the garden, the booklet furnishes abundant and detailed directions for testing
and saving the seeds of the more common flowers and vegetables, for the planting
of trees, the making of hot-beds, the making of window gardens, and for the
culture of strawberries and other fruits. The directions are clear and give with
sufficient detail the points most useful to the beginner.—H. HassELBRING.

Das Pflanzenreich.—Part 25 of this work has just appeared® and ‘contains a
Presentation of the Juncaceae by the late Dr. Fr. BuCHENAU. The usual full

iscussion of the various structures of the family and its geographical distribu-
tion is followed by a synopsis of the 8 genera, among which the species are dis-
tributed as follows: Distichia (3), Patosia (1), Oxychloe (2), Marsippospermum
(3), Rostkovia (1), Prionium (1), Luzula (61, of which 2 are new), Juncus (209,
ol which 5 are new). The whole presentation is remarkably full in details of forms
and in illustrations, and is of particular interest to American botanists.—J. M. C.

Index Filicum.—The ninth fascicle of CHRISTENSEN’s work has appeared,’
Carrying the references from Polypodium Beddomei to Polystichum aculeatum.

ae genus Polypodium fills the whole fascicle excepting the last page.—

NOTES: FOR STUDENTS.

Plant diseases —Crinton,$ in his report as Botanist of the Connecticut
Experiment Station for 1905, presents interesting notes and illustrations of
several fungous diseases of plants in that state, followed by a more detailed
IN a TS

4In the United States, in Jour. Mycol. 10: 109. 1904.

5’ HEMENWay, H. D., Hints and helps for young gardeners, a treatise designed
for those young in experience as well as youthful gardeners. 8vo. paper. pp. 59-
illustrated. Hartford, Conn.: The Author. 1906. 35 cents.

° ENGLER. A.-Das Pflanzenreich. Heft,25, Juncaceae by FR. BUCHENAU. ae
PP. 284. figs. rar (777). Leipzig: Wilhelm Englemann. 1906. M 14.20.

’ CHRISTENSEN, C., Index Filicum, etc. Fasc. 9. Copenhagen: H. Hagerups
Boghandel. 1906. 35. 6d.

8 Cuinton, G. P., Report of the Botanist. Rept. Conn. Exp. Stat. 1905:
263-330. ‘pls, 7 3-25. figs. 8-9. 1906.

.

64 BOTANICAL GAZETTE [row

account of the downy mildew of the lima bean, due to Phytophthora phaseoli,
and of the downy mildew or blight of the Irish potato, due to Phytophthon
injestans. ‘The two latter diseases are fully described and illustrated, and cita-
tions of the literature of each disease are given.

WHETZEL” gives an illustrated account of the following bean diseases found
in New York state: anthracnose, due to Colletotrichum lindemuthianum; blight,
due to Bacterium phaseoli; and rust, due to Uromyces appendiculatus. Methods
of treatment are also given in each disease.

SHELDON” has just published the results of his study of the ripe rot or mummy
disease of guavas. This disease is similar in many respects to the ripe rot or
bitter rot of apples. It is produced by Glomerella psidii (G. Del.) Sheldon. He
found the ascigerous stage and worked out the life history of the fungus in con-
siderable detail. :

ORTON** has published a brief summary of the present knowledge of the

diseases of the Irish potato in Maryland together with methods of treatment of

these diseases.

application of this remedy is possible. The second disease mentioned is the
summer blight, due to a species of Fusarium which attacks the plant in much
the same manner as does the fusarium Stage of Neocosmospora which causes
the wilt of cotton, etc. The third disease mentioned is the winter blight, due to
the potato-blight fungus, Phytophthora infestans. It occurs only after heavy
fogs, dews, or rains, and hence in California attacks only the winter crop. Spray
ing with Bordeaux mixture is recommended to be applied just after the rains
or dews.

9 WHETZEL, H. H., Some diseases of beans. Bull. N. Y. Cornell Exp. Stat
239:195-214. figs. Ioo-114. 1906.

10 SHELDON, J. L., The ripe rot, or mummy disease of guavas. Bull. W. Ve
Exp. Stat. 104: 299-315. pls. I-4. fig. I. 1906.

*t Norton, J. B. S., Irish potato diseases. Bull. Md. Exp. Stat. 108:63-7?
figs. I-4. 1906.

*? STEVENS, F. L., Report of the Biologist. Rept. N. Car. Exp. Stat. 1904-
PP- 10. 1905.

"$ SmiTH, R. E., Tomato diseases in California. Bull. Calif. Exp. Stat. 1757 |

I-16. figs. I-8. 1906.

-

1 PEC as ane See een

1906] CURRENT LITERATURE 65

RrEp"+ has described three fungous diseases of the cultivated ginseng.
These diseases are not due to the same fungi reported by VAN Hoox’s as causing
ginseng diseases in New York. The first of these is a stem anthracnose due to
Vermicularia dematium. The second is a leaf anthracnose due to Pestalozzia
juneria. These two diseases he finds may be controlled by spraying with the
usual Bordeaux mixture. The third disease described is a wilt due to Neocos-
mospora vasinjecta nivea. This same variety causes a wilt disease of the water-
melon, while the species itself causes a wilt disease of cotton and the cowpea.
REED finds that the wilt never occurs except in association with or following an
attack of the stem anthracnose. In other words, the wilt fungus seems to be able
to gain entrance to the ginseng plant through the lesions on the stem due to this
other stem disease. It is also possible that the wilt fungus enters the plant at
the scar left where the stem of the preceding year fell off. It should be recalle
in this connection that the cotton and cowpea wilt-fungus enters the host through
the roots largely after injury by the nematode worm.—E. MEAD WILCox.

SorAvER’® describes a peculiar disease of Cereus nycticalis Lk. which results
from proliferation of cells of the inner layers of the cortex. This produces on
the stems slightly elevated hygrophanous areas which increase in size until they
occupy a large part of the stem and extend to the wood. These turn brown and
then black and finally collapse, leaving depressed wounds in the stem. On
account of the position of the proliferating cells SoRAUER designates these growths
as “internal intumescences. ” e diseased regions are almost free from starch,
but they are rich in glucose, which the writer regards as the cause of the unusual
growth. This condition is brought about by high temperature and excessive
moisture. When these factors were changed no “‘intumescences” were formed.
—H. Hassererine.

The maturation mitoses.—A critical review of the entire subject of the matu-
ration mitoses in both plants and animals has been prepared by GREGOIRE.*? -
Part I, dealing with stages from the metaphase of the first mitosis in the mother-
cell up to the telophase of the second division, contains 155 pages and 147 text
figures, of which 35 pages and 35 figures relate to sporogenesis in plants, 90
pages and 112 figures to spermatogenesis and oogenesis in animals, and the
remaining 30 pages to a comparative study. The space given to animal mitoses
increases the value of the work to botanists, who are already more or less familiar
with the botanical literature. At the close of the botanical section the conclusion

4 ReeEp, H. S., Three fungous diseases of the cultivated ginseng. Bull. Mo.
Exp. Stat. 69: 41-66. figs. I-9. 1905. :

*S Van Hook, J. M., Diseases of ginseng. Bull. N. Y. Cornell Exp. Stat. 219:
163-186. figs. 18-ga. 1904.

*© SoravER, P., Zeitr. Pflanzenkrankheiten 16:5-10. pl. 2. 1906.

'7 Gr&corrE, Victor, Les resultats acquirés sur les cinéses de maturation dans
les deux régnes. Premier mémoi Revue critique de la littérature. La Cellule
22: 221-346, figs. 147. 1905.

66 BOTANICAL GAZETTE [JULY

is reached that the definitive chromosomes of the first mitosis constitute two
branches which are variously placed with relation to each other. These two
branches are the daughter chromosomes of the first mitosis. During the meta-
phase or anaphase these daughter chromosomes split longitudinally. In the
telophase no complete spirem is formed nor do the nuclei reach the resting
condition, but the chromosomes preserve their individuality so that the longi-
tudinal portions which appeared in the anaphase of the first mitosis become the
daughter chromosomes of the second mitosis. Consequently, the second mitosis
cannot be a reduction division. Whether a reduction takes place at the first
mitosis will be discussed in the second memoir. In the general résumé the
conclusion is reached that in both plants and animals the definitive chromo-
somes of the first mitosis, at the equatorial plate stage, are composed of two
continuous branches. There are two categories of theories as to the significance
of the second mitosis, the one holding it as an equation division and the other
as a reduction division.

In regard to the two constituent branches of the chromosomes of the first
mitosis, there are two possibilities: if they are longitudinal pieces of a segment
of a primary chromosome, the heterotypic division is an equation division; if,
on the other hand, each of the two branches is a complete somatic chromosome,
there is a true reduction in the WEIS MAN sense. The important question is,
How are the chromosomes of the first mitosis formed? This will be the subject
of the second memoir.

The work will be welcomed by cytologists, for the subject matter is well
arranged and conflicting theories are impartially discussed. While the title
indicates only a critical review of the literature, the work is something more,
because so much botanical investigation has been done in the writer’s own lab
oratory, and because even the zoological section has not been written entirely
from the literature, but from the writer’s own preparations and numerous prepa
rations loaned by prominent investigators of animal cytology.—CHarLEs J.
CHAMBERLAIN.

Nova in hybrids.—As has been already noted" in these pages, TSCHERMAK
found a large number of instances in which nova appeared in hybrid beans and

peas, in very definite ratios which were readily related to the ordinary Mende-

lian ratio. These nova were explained by him as characters latent in one of

action of two or more pairs of units, the positive member of some or all but one

of these pairs of units being invisible because of the absence of the other mem

ber of the combination. For example, an albino mouse bred with a brow?

mouse may produce black offspring, because the albino contains a unit which :

8 See Bor. GAZETTE 39: 302. Apr. 1905.
9 See Bor. GazETTE 40: 234. Sept. 1905.

aioe

a

we

4
4
2
4

Fe eee ee ne es ee ee

1906] CURRENT LITERATURE 67

has the power of changing the gray pigment to black, but this pigment-changing
unit will remain invisible so long as the albino is bred only with other albinos.

Under this conception the novum is a compound character formed by the
combination of equivalent units, instead of a hitherto inactive character ren-
dered active by the stimulating effect of a foreign plasma. TscHERMAK?° now
assents to the explanation of CuENoT and Correns as valid in certain cases,
but still maintains that the nova of his Pisum arvense X sativum crosses and others
cannot be so explained, because he found no cases in which the offspring were not
all cryptomeric. TsCHERMAK’s reference to the fact that the mova are fre-
quently of atavistic nature, as lending support to GALToN’s “law of natural inheri-
tance,’’ will scarcely be approved, since the explanation of CUENOT and CORRENS
would bring these into agreement with typical Mendelian hybrids.

BatEson** has likewise adopted the explanation of CUENOT and CORRENS
in the interpretation of mova in sweet peas and stocks which had been pre-
sented’? in the Second Report to the Evolution Committee, as wholly out of
harmony with Mendelian inheritance. These now constitute exceptionally good
examples of characters which can only become manifest when two or more
units act together. The statement is made that most of the five gametically
distinct types which should appear among the white sweet peas and white stocks
of these crosses have been recognized, thus answering satisfactorily, in respect
to these two species, TscHERMAK’s contention that the extracted whites were
still cryptomeric.

he same explanation is clearly valid for the case reported by CasTLE?
in which a white guinea- pig crossed with red gave rise to some black offspring,
while the “extracted” whites from this cross, when crossed with red, produced
no black young—Grorce H. SHULL

Welwitschia—The full paper on Welwitschia mirabilis by Parson has
now appeared,?4 the abstract of last November having been noted in this journal.’s
The region of this strange plant is so difficult of access that Professor PEARSON
is to hes commended for the unusual efforts he has put forth to secure eae
As it happened, fee war in Africa has seriously interfered with his
that he was able to secure material of only one day’s collecting, but he hopes
that when the Siectig becomes more settled he will be able to fill in the gaps.

ts
° TSCHERMAK, E., Die Mendelsche Lehre und die Galtonsche Theorie vom
— Arch: & Rasa Gesells. Biol. 2:663-672. 1905-

** BATESON, W., SAUNDERS, E. R., and Punnett, R. C., Further experiments
on inheritance in sweet peas and stocks: Preliminary account. Proc. Roy.
London B. 77:2 236-238. 1905.

22 See Bor. GazettE 40: sak: 1905.
*3 See Bor. GazeTTE 40: 385. 1905.

74 PEARSON, H. H. W., Some observations on abies mirabilis Hooker.

Phil. Trans, Soc. London B. 198: 265-304. pls. 18-22. 19
*S Bot. GazettE 41:226. 1906.

68 BOTANICAL GAZETTE [jury

The plant is of such unusual interest that his results deserve rather ful
statement.

resembles that described for Ephedra and Gnetum; and at dehiscence thre
nuclei are found in the pollen grain, one of which, probably prothallial, disap
pears before shedding. The single megaspore mother cell forms the usu:
linear tetrad, the innermost spore functioning. In the germination of the meg
spore there is abundant free nuclear division, and a strong growth of the sé
towards the micropyle and into the chalazal region. The formation of
walls occurs throughout the embryo sac, the cells thus formed often being mul
nucleate. Each peripheral cell towards the micropyle, containing two to fin
nuclei, produces a tubular outgrowth which penetrates the nucellar cap like
pollen tube. As this tube advances the nuclei pass into it, and the in
traversed before pollination occurs is considerable. These free nuclei are s
and hence the condition is that of Gnetum. These tube-forming cells have bee
taken for archegonium initials, but it is evident that the tube is only an e
of the prothallium containing free sexual nuclei; and hence PEARSON r
calls it the “ prothallial tube.”’ This is a most satisfactory disposition of a trou
Some structure; and we find that in the act of fertilization Welwitschia is
more specialized than is Gnetum. :

It is to be regretted that the first stages of embryo-formation were not s
by the material, for the current statements in reference to it are as obscure
meaningless as have been those in reference to the so-called “archegonium
tials.”—J, M. C. .

Mendelism in agriculture —No other single scientific proposition has
so much interest from agriculturists and breeders as MENDEL’s laws of

sixteen pairs of characters in wheat, five in rye, thirteen in barley, and
in oats. A short section is devoted to the technic of crossing, and another
the importance of establishing stations and properly equipping them for ca’
ing on such investigations, ee

76 TSCHERMAK, E., Die Kreuzung im Dienste der Pflanzenziichtung.
Deutsche Landw. Gesells. 20: 325-338. 1905. :

- 1906] CURRENI LITERATURE 69

HALsTED?’ has also issued a bulletin which gives a good general discussion
of Mendelism as exemplified by cooperative experiments in the breeding of
corn. In 1904 ‘Black Mexican” sweet corn was crossed with nearly a full
list of the commercial varieties of sweet corn, and the hybrid ears thus obtained
were sent to a number of volunteer observers in different parts of the state, who
returned samples and notes which are incorporated into this bulletin. The
presentation is simple and easily understood, but several unfortunate typo-
graphical errors are likely to prove confusing, as when on p- 15 in the table show-
ing what may be expected in the second generation of a cross between large
grained flint black, and small grained sweet white, the fourth category (large
sweet white) is weighted with the ae 9 instead of 3; and again, when on p. 21,
line 7, “‘white” is used for “ dark.’

An improper emphasis is laid upon the difficulty of fivelig the dominant
form from traces of the recessive. Thus, he says that after nineteen genera-
tions of selection there will still be one recessive grain in each four hundred,
adding that “this underlying rule,” which appears to hold more or less closely,
helps to indicate how difficult it is to eradicate entirely any characteristic
that has been introduced in breeding.” He seems -to have overlooked the
importance of VitMorIN’s principle of isolation, by which it requires only one
more generation to obtain pure extracted dominants than extracted recessives,
So that after the third generation he need never have another recessive grain
appear.—GEorRGE H. SHULL

Inheritance in Shirley poppies—Prarson and his associates, with the aid
of a number of volunteer observers, have presented a second paper?® on inher-
itance in the Shirley poppy. Some of the questions that were left open in the
earlier report?® have been settled. Thus, it was assumed that Shirley poppies
both self- and cross-fertilize, and the discussions were based upon that assump-
tion. It is now found that when flowers are enclosed in bags of bolting-cloth
or oiled paper, almost no fertilization takes place. Fifty bagged flowers pro-
duced seeds in only four, and these gave rise to nine plants. The conclusion
is reached, therefore, that seeds taken from unprotected capsules are essen-
tially the result of cross-fertilization; and the correlation of offspring with each
other and with their antecedents should be the same as in other populations
in which self-fertilization does not occur, as in animals and man. Although
the correlation found is somewhat lower than the average for animals, a number
of modifying factors are pointed out which would tend to lessen the correla-

27 HALSTED, B. D., Bre eeding sweet comn—cooperative tests. N. J. Agr. Exp.
Sta. Bull. ae pp- 30. pls. 4, figs. 8. March 19

RSON, K., et al., Cooperative investigations in plants. . On inheritance
n the Shirley poppy. - eres Memoir. Biometrika 4: 394-426. 1 = (colored). 1906.
29 Pearson, K., et al., Cooperative investigation in plants. I. On inheritance

n the Shirley Poppy. aan 2:56-I00, 1902.

70 BOTANICAL GAZETTE [yu LY

tion, and the opinion is expressed that there is no reason to believe that
strength of inheritance is any different in Shirley poppies from that in anim

Another gain is seen in the recognition of the entire plant as the here
unit, instead of the separate flowers, the latter view having been maint
in the earlier paper.

The characters used were the number of stigmatic bands, number of
and petaloid stamens, color of petals, presence of a margin, presence of a
spot and its color, and wrinkling of the petals. Each of these characters '
divided into a number of categories designated in a manner that makes
personal equation a very esha factor, e. g. with reference to the presence ¢
basal spot, the classes are ‘none, none i slight, slight, slight to well-defin
well-defined, well-defined to large, large.” The observers found these ca
gories very difficult to separate, and think there is no evidence of allelomo

of Shirley poppies could awe be expected to show evidences of allelomorp
characters.—GEorGE H. SHuL

Drying of seedlings and sporelings——RaseE finds that germinated sé
and spores resist drying more or less well.3° With advancing germinative s
and exhaustion of reserve food the resistance to drying diminishes.
will withstand much longer drying in the air than in a sulfuric acid desicca
The separated hypocotyl of a seedling always dies upon being fully dried 0
The cotyledons are more resistant than the plumule, and of the latter the grow
point and the axillary buds are more resistant than the leaves. The separates
and dried portions of the seedling, if they are yet alive, are as vigorous in repro
ducing as the separated portions of the fresh seedling. In spite of the defective
storage and marked shrinkage, the seedling of the unripe seed will withsta
drying nearly as well as the seedling of the ripe seed. Seedlings of xeroph.

are more resistant to drying than those of hydrophytes. The presence of th

ssio
of related species show no relation in their power to withstand ‘efi Watet
free chemical reagents, as alcohol and benzene, act more harmfully on germin
dried seedlings than on ungerminated dried seeds. The germinated dried

in the air or in a sulfuric acid desiccator. Germinated spores of ferns and
worts withstand but little drying. The power of plants to withstand dry
depends mainly upon the peculiar properties of their protoplasm.—Ww. Crock!

3° RABE, FRANz, Ueber die Austrock gsfahigkeit gekeimt Samen und Spore
Flora 95: 253-324. 1905.

1906] CURRENT LITERATURE “es

Anatomy of Cyperaceae.—The comparative anatomy of the Cyperaceae has
been studied by PLowMan,3" and as usual the chief interest centers in the
stem. Amphivasal bundles are found throughout the rhizomes of all large-leaved
species and at the nodes of aerial stems; elsewhere the bundles are collateral.
The amphivasal bundles arise through the introduction into the node of the
numerous leaf-trace bundles, and are independent of the branching of the stem.
Hence the leaf is to be regarded as the dominant factor in the development of
the stelar characteristics of the family and probably of the other monocoty-
ledonous families. The course of the bundles in the rhizome approaches the

“palm type,” but in the culm the leaf-trace bundles pass down as cortical bundles
through one internode and then fuse with the bundles of the central cylinder
by a ring-like amphivasal plexus. The seedling and in some cases the floral
axis show a simple tubular stele, which is to be regarded as the primitive condi-
tion, in contrast with the medullary and amphivasal bundles occurring in many
parts of the plant. A cambium is present in the bundles at the nodes of Scirpus
cyperinus and other species. These features indicate that the Cyperaceae
is one of the more primitive groups of monocotyledons, though showing signs
of specialization and reduction, accompanied by a high degree of anatomical
unity. The view which derives the monocotyledons from an essentially dicoty-
ledonous ancestry receives further support. The author proposes a division
of the family into ‘‘Amphivasae’”’ and “‘Centrivasae;” he also gives a key to
the genera, based on anatomical characters. The paper is accompanied by a
number of excellent photomicrographs.—M. A. CHRYSLER.

Origin of Cycadaceae.—WorspDELL3? has published a résumé of his views
as to the origin of the Cycads from the Pteridosperms, with full bibliography.
The part dealing with the origin of axial structures is of greatest interest; and the
thesis is that the Medullosan ancestry is clear. It is claimed that the coty-
ledonary node and the axis of the strobilus are the two principal regions for
revealing ancestral characters. Much stress is laid upon Matrte’s discovery
of polystely in the cotyledonary node of Encephalartos Barteri; and also upon
the very irregular orientation of the bundles of the peduncle of Stangeria.
According to the author’s view, the endarch cylinder of Lyginondedron and of
the Cycads is of polystelic origin, coming from Medullosan ancestors, each

constituent bundle being the homologue of the single bundle of the monostelic
_ Heterangium. The endarch condition arises from the degeneration of the

internal vascular tissues. Numerous illustrations are given, intended to show
how the various vascular structures of both Pteridosperms and Cycads suggest
this view and are most easily explained by it. The whole presentation is

3* PLlowMaN, A, B., The comparative Se and phylogeny of the Cyper-

_ aceae. Annals of Bota 20:1-33. pls. I-2. t

32 WorDSELL, W. C., The structure and origin of the Cycadaceae. Annals of

_ Botany 20:129-159. figs. 17. 1906.

72 BOTANICAL GAZETTE [yor

particularly valuable in ea scattered data together in compact forsiay a
thoug Say may va to their interpretation

w term of sdaasdestion is introduced i “‘Cycadophyta,”
istinad: Pciipetia (Cycadofilices), Bennettitales, and Cycadales.
author also discredits somewhat the value : = ontogeny of the vascular s
tures as indicating their phylogeny.—J.

Osmosis and osmotic pressure—A revolutionary paper upon the n
of osmosis and osmotic pressure, has: been published by KaHLENBERG,33

‘is, he claims, no such ae as a strictly semipermeable membrane, since
movement in the reverse direction always occurs, though it is often insigni
or practically negligible. The force concerned in osmotic processes
merely in the specific ities between the solvent and the solutes, but p
in their relation to the ee whether it be called “‘potential ene
solution,” ‘‘internal pressure,” or (as KAHLENBERG prefers) “chemical a
In measuring osmotic ficbaiities ie which he devised a new apparatus i TT

the liquids is absolutely essential—a factor not previously reckoned with;

a general rule, solutes conform to the behavior of gases, however closely some
water may do this. The r deserves the closest attention from every phi
ologist; yet the hes evidence against KAHLENBERG’s conclusions must 1
be forgotten.—C. R. B

The vitality of buried seeds.—Duvet gives a preliminary account of e2
ments on the vitality of buried seeds,34+ of some of the common economic Pp
and weeds of the United States, representing rog species, 84 genera, and 34
lies. In December, 1902, eight to twelve lots of each species of seeds”
buried at three depths: 15-20, 46-56, go-105 °™. A sample of each is to
taken up at sh te periods and tested for vitality along with controls 5!
in a dry pl

Tests is a date show the following results. In some cases none of eith
controls on the buried seeds grow. Among these are: Axyris amaranth
Bursa bursa-pastoris, Polygonum pennsylvanicum, P. persicaria, P. sca

33 KAHLENBERG. L., On the nature of the process of osmosis and osmotic
sure, with observations concerning dialysis. . Journ. Phys. Chem. 10:141-209-
Published also in Trans. Wis. Acad. 15:209-272. 19¢ r

34 DuvEL, J. ss T., Vitality of buried seeds. Bureau Plant Indy Bul
pp. 22. pls. 3. 190

be published later. However, he represents a single cell at the “‘spore pole

1906] CURRENT LITERATURE 73

A second group, among which are the common cereals and various other plants,
as Lactuca sativa, Helianthus annuus, Asparagus officinalis, Pinus virginiana,
Robinia pseudacacia, either all decayed before germinating or germinated and
then all decayed before being examined. A third group, which includes our
more noxious weeds, retained their vitality to a considerable degree. The

_ deeper the seeds were buried the better they retained their vitality. Vitality is

best preserved, even in weed seeds, when they are carefully harvested and
stored in a dry and comparatively cool place—W. CROCKER.

Prothallia and sporelings of Botrychium.—BrUCHMANN?5 has been inves-
tigating Botrychium Lunaria. Since this species has no means of vegetative
multiplication, like the adventitious shoots of Ophioglossum vulgatum, every
sporophyte must have come from a gametophyte. The prothallia are hard
to find because they are very small (1-2™™ long and o.5-1™™ wide),-and the
sporelings grow for several years before they reach the surface of the soil. The

_ prothallia are found at a depth of 1-3°™. In form and general character the

prothallium of B. Lunaria resembles that of B. virginianum, except that it is

‘much smaller. BrucHMANN succeeded in germinating the spores and his

results agree with those of CAMPBELL, who got the two and three-cell stage in
Ophioglossum vulgatum. Further work upon this aspect of the problem will

of the prothallium and regards this as the first cell of the prothallium, represent-
ing the protonema stage. Nearly every prothallium bears an embryo and some

prothallia have two. The first division of the embryo is transverse. Growth

is very slow, the sporeling being three years old before it reaches the surface.
One plate and considerable attention in the text is devoted to the anatomy of
the mature plant.—CHartEs J. CHAMBERLAIN.

Spermatozoids of Cycas revoluta.—MrvyakeE*® studied the living sperma-

tozoids at the island of Oshima (28° 30’ N) in September, and in southern Japan

(31° 35 N) from the beginning to the middle of October. The diameter of
the spermatozoids varies from 180 to 210“. The two spermatozoids are sur-
rounded by a delicate membrane, but it could not be determined with certainty
whether the membrane belongs to the spermatozoid or is merely the Haut-
schicht of the protoplasm of the pollen tube. For observing the movements
the spermatozoids were placed in a 10 per cent. cane sugar solution. The move-
ments often continued for one to three hours; and in one case for six hours and
forty minutes, and in another case for five hours and thirty minutes. In some
cases the spermatozoids were shot out suddenly from the pollen tube, which
seems to be the method that occurs under natural conditions. The forward
movement is always accompanied by a rotation from left to right about the

33 BRUCHMANN, H., Ueber das Prothallium und die Sporenpflanze von Botry-
06.

_ chium Lunaria Sw. Flora 96: 203-230. pls. 1-2. 19

3° Miyake, Ueber die Seema von ee revoluta. Ber. Deutsch. Bot.

Gesell. 24: 78-83. pl. 6. 1906.

74 BOTANICAL GAZETTE 7

i
axis. In some cases the forward movement was found to be at the rate 0
o.7™™ per second. MIYAKE agrees with WEBBER that the liquid in the arche
gonial chamber at the time of fertilization comes from the pollen tube and no
from the archegonium.—CHarLEs J. CHAMBERLAIN.

Heterostyly and gynodioecism.—Inheritance of dimorphism has been inves
tigated by RAuNKIARS7 in Primula, Menyanthes, Pulmonaria, Fagop “um,
Knautia, and Thymus. In all heterostylic aes studied he finds that
long-styled and short-styled forms occur in about equal numbers regard
of the character of the environment. In gynodioecious species, on the 0
hand, he finds considerable variation in the proportions of the two forms
different localities. The results of breeding are in close accord with those
C :

e
angiate plants of eae vulgaris produced 65 be cent. pistillate plants

beckvatetic and dolichostylic x dolichostylic 0 only 4.3 per cent. brachy
Investigation covering several generations is needed to determine the
of the pre-parental ancestry, and until this is done, any speculation as t
hereditary nature of the forms of a dimorphic species can be of little v
GrorGE H. SHULL.

Development of spores of Helminthostachys—Brrr3® has _ investi
the development of the spores of H. zeylanica, his material being fertile
preserved in spirit. CARprrrF,4° and afterwards STEVENS,‘! had

of the plasmodium-like tapetal eee in Botrychium; and BEER finds
same phenomena in Helminthostachys. His observations extend, hov
to the specific work of the el plasmodium in spore-formation. The ¢
served facts are that during the period of exospore growth the tapetal p

odium shows more or less complete disappearance of starch, gradual
nution of the finely vacuolar cytoplasm, and richly chromatic nuclei which
show irregularities of outline. The conclusion is that the tapetal plasmo
is the center of metabolic activities in which a substance is elaborated from
raw materials contained in the a igre is employed, directly or indi
in the growth of the spore wall.—J. M

37 RAUNKIAR, C., Sur la transmission par hérédité dans les — hét
phes. Bull. Acad. Roy. Sci. et Let., Denmark, pp. 31-39, 1906.

38 See Bot. GAZETTE 39: 304. 1905. and 41: 302. 1906.

39 BEER, RUDOLF, On the development of the spores of Helminthostachys
Janica. Annals of Botany 20:177-186. pls. II-12. 1906.

4° Bot, GAZETTE 29: 340-347. pl. 9. 1905.

4" Annals of Botany 19:—. —. 1905.

1906] CURRENT LITERATURE 45

Seedlings of Piperales —In continuing his work on the structure of the seed-
lings of certain Piperales, Hrt1+? has published results dealing chiefly with
several species of Peperomia. The transition phenomena are described in
detail; that is (in brief), the arrangement of the vascular tissues in the cotyle-
donary or primary node, the transition region between root and stem, where the
earliest tissues of the vascular system arise. The conclusion in reference to
the primitive or reduced character of Peperomia is confirmatory of JoHNSON’s
view that it is a reduced genus, the determining factor in reduction possibly
being the epiphytic habit of many forms. It is also suggested that these tran-
sition phenomena may not be such important phylogenetic criteria as has been
assumed by some investigators, since they do not seem to be sufficiently rigid
to withstand the influence of varying conditions.—J. M. C.

Antipodal cells —In a long article LorscHER‘ discusses the structure and
function of the antipodal cells of angiosperms. On the basis of their anatomy
and physiology he finds three types of antipodals: (1) those remaining as naked
protoplasts or free cells and functioning in the resorption of the nucellus (Orchid-
aceae, Cruciferae, Geraniaceae; Linaceae, Papilionaceae, Primulaceae, Pol-
emoniaceae, and Scrophulariaceae); (2) those well differentiated and forming
a roundish cell-complex which serves to transform the foodstuffs which are
brought to the embryo-sac (Gramineae, Araceae, Ranunculaceae, Mimosaceae,
Cesalpinaceae, and in combination with the third type, predominant in Lili-
aceae, Iridaceae, Zingiberaceae, Borraginaceae, and Solanaceae); (3) those,
singly or together, having an elongated form and functioning principally as
haustoria (most Rubiaceae).—CHARLES J. CHAMBERLAIN.

Mechanics of secretion This problem has been attacked by LEPESCHKIN,
who finds44 that from “unicellular” plants (Pilobolus, Mucor, Phycomyces,
and Vaucheria are so called), as well as from the epidermal structures of green
plants, secretion is to be referred to the unlike permeability for solutes of the
plasma membrane in the absorbing and secreting regions of the structure. The
process of secretion and the influence of external agents upon it agree com-
pletely with the mathematical formulae for the energy involved, based upon
the current theories of osmotic pressure. The permeability of the membrane
is easily altered by external and internal influences. Whether this is character-
istic of all semipermeable membranes or only of plasmatic membranes remains
to be determined. The research adds some facts but leaves much yet to be ex-
plained regarding the subject.—C. R. B

4? Hitz, T. G., On the ES of certain Piperales. Annals of Botany
20:160-175. pl. Io. 1906.
43 LorscHer, P. Konrap, Ueber den Bau und die Funktion der Antipoden in

Ko
der PR te Flora 94:213-262. pls. I-2. 1905.

SCH
aactcttie der Pflanzen. Beihefte Bot, Cent. 19:409-452- 1906.

76 BOTANICAL GAZETTE

(yu

Pollen grains of Picea.—Po.ttocxk4’ has described variations observed
the pollen grain structures of Picea excelsa, chiefly in reference to the so-call
ahaa cells. The usual number of these cells reported for the Abietine
is two, but PoLtock finds the variation in Picea to range from one to thr
ae one as.the number in the majority of cases. This is an interesting sitt
tion, as these cells have been reported thus far for the conifers only among tt
more easy Abietineae and Podocarpeae, and it shows that even here th
are in a very fluctuating condition. The condition among the Arauca ne
recently announced by THomson, is interpreted as representing a still grea
multiplication of prothallial cells, an interpretation that is probably jus
That among the conifers all stages in the elimination of this tissue are represen
seems evident.—J. M.-C

Sclerotinia on Forsythia.—OsTERWALDER*® has described a disease of s

from. those date. causing a wilting of the twigs alone. Sclerotia are f

the typical apothecia of Sclerotinia. Spores or mycelium grown the
-produced the disease anew when placed on the floral parts. Although
conidiophores occurred on some of the withered flowers, the author was
to show that these were not connected with the Sclerotinia, thereby sue
the view that Sclerotinia Libertiana has no conidial form.—H. Hasse

A sterile Bryonia hybrid.—In studying the development of the sex org
of a sterile hybrid of Bryonia alba and B. dioica, TIscHLER47 comes to the ¢
clusions that the absolute sterility has nothing to do with the tetrad form
because the megaspore series shows the normal tetrads, and that while
are irregularities i in the formation of pollen there are also cases in which no!

bining culture methods and cytotogy—Cxar.Es J. CHAMBERLAIN

Photosynthesis.—UsHER and PRIESTLEY have contributed strong suppor
the theory of BAEYER that formaldehyde is the first product of photolysis of C'

4s Pottocx, James B., Variations in the pollen ago of Picea excelsa.
Nat. 40:253-286. pl. 1. 1906.
4° OSTERWALDER, A., Die Sclerotienkrankheit bei den paren
Pflanzenkr. 15:321-329. pl 5. 1905. :
47 TISCHLER, G., Ueber die Entwicklung der Sesnanewaaine bei einem st
Pimiefieressry Ber. Deutsch. Bot. Gesell. 24:83-06. pl. 7. 1906.

E1906] CURRENT LITERATURE 77

4 They find+* an enzyme in spermatophytes and pteridophytes generally, which
| decomposes H,O, energetically, with the evolution of O,. When this enz zyme
4 is destroyed or its action inhibited, the chlorophyll is quickly destroyed and the
| plant bleached. They also demonstrated the formation of formaldehyde (when
_ its prompt condensation was prevented) in the immediate vicinity of the chloro-
_ plasts. The usual condensation of the HCOH is due, they hold, to the proto-
a plasmic stroma of the chloroplast and not to an enzyme; yet the experiment on
4 which they rely is not conclusive on this point.—C. R. B

Seeds of Euphorbiaceae —A study of the development of the seeds of numer-
_ ous genera and species of Euphorbiaceae has given SCHWEIGER#? the following
results: The obturator, a tissue which serves for the conduction and nutrition

_ to the seed. The tip of the nucellus is often much elongated, and until fertili-
4 zation is effected is often in direct connection with the obturator. The caruncle
‘ belongs to the seed, is developed from the outer integument, and serves to
_ Separate the seed from the placenta.—CHarLEs J. CHAMBERLAIN.

q Zygospores of Mucor.—According to HaMaxkErs° the production of zygo-
Spores of Mucor stolonifer, with proper conditions of moisture and temperature,
_ is dependent only upon the nature of the substratum. The atmosphere should
_ be saturated with moisture and the temperature about 70° F. The substratum
_ used is corn muffin bread, which the baker makes after the following formula:
corn meal, 16 pounds; flour, 3 pounds; lard, 3 pounds; salt, } pound; eggs,
_ 48; sweet milk, 3 gallons; baking powder, 18 ounces. In a large proportion of
_ cultures zygospores appear in five to seven days.—CHARLES J. CHAMBERLAIN.

Germination of pollen—Josr has succeeded in germinating the pollen
grains of various grasses,5' which have heretofore proved refractory, by growing
_ them under conditions where they can obtain water very slowly from the medium

by which it is held. Thus, a starch paste made with only one or two parts of
water proved useful; and also parchment. paper soaked with a sugar solution.

tag pollen grains of certain Compositae have also ont to the latter treatment,
ut none of the Cichoriaceae or Umbelliferae —C. R. B

on

4 Usuer, F. L., and Prrestiey, J. H., A study of the mechanism of carbon
_ assimilation in green ‘phe, Proc. Roy. Soc. London B. 77: 369-376. 1906.

ScH R, JOSEPH, Beitrige zur Kenntniss der Samenentwickelung der
’ Sirah ec on 94: 339-379. 1905.
a S° HAMAKER, J. I., A culture medium for the zygospores of Mucor peso
Becience N. S. 23:710. 1906.
. he oe L., Zur Physiologie des Pollens. Ber. Deutsch. Bot. Gesells. 23:504-
15.

78 _ BOTANICAL GAZETTE [yory

Dry rot.— Butters? describes the destruction of pine paving blocks in
Birmingham, England, by Lentinus lepideus Fr. This fungus produces a dry ©
rot which in its microscopic and chemical aspects resembles the destruction — |

hadromal is left behind. The ravages of the fungus were somewhat chec ed
by a dipping in creosote which the blocks had received before being laid down. 4
—H. HAssSELBRING a

Self-digestion of endosperm—Ponp summarizes’; the literature on this 4
point, and finds no clear proof that the amylaceous endosperm of grasses or '
the horny endosperm of palms is capable of self-digestion, though this has been —
claimed by authors and the claim has been accepted hitherto. He himself care- —
fully tested this point in the seed of the date, Phoenix dactylifera, and finds” 4
its endosperm incapable of self-digestion—C. R. B.

Formation of chlorophyll.—According to PaLiapIN this is a process of a
oxidation, dependent upon the presence of sugar solutions of low concentration =

and is not inhibited by concentrations of even 30-50 per cent. sugar in detached
leaves of Vicia Faba.—C. R. B.

Caprification—Lonco has been investigating the fig and caprifig, and in _
advance of the full memoir with illustrations has published a brief preliminary —
announcement.5s As the differences from previous accounts are those of detail —
rather than fundamental in character, a review will be deferred until the appear-
ance of the full paper—J. M. C

Anatomy of Epigaea.—The histology of the stem and leaf are described
ina paper by ANDREws.5° The most noteworthy point is the occurrence of
glandular hairs on the lateral pan iN the suggestion is made that these
aid in absorption of food.—M. A. Cur

5? BULLER, A. H. REGINALD, The destruction of wooden paving blocks by the
fungus Lentinus lepideus Fr. Jour. Economic Biol. 1: 1-12. pls I-2. 1905.

53 POND, R. H., soe Soe of the date endosperm for self- -digestion. Annals
of Bot. 20: be

54 ISSATCHENKO, ‘: , Sur les preneice de la formation de chlorophylle. Résumé
Bull. Jard. Imp. Bot. St. Petersb. 6:27. 1906.

55 Lonco, B., Ricerche sul fico e ie caprifico. Rend. Accad. Lincei 15:3737
377- 1906.

56 ANDREWS, * M., Die Anatomie von Epigaea repens L. Beih. Bot. Cent. 19+
314-320 pls. 6-8. 1905.

NEWS.

Dr. W. W. Row Leg, Cornell University, has been advanced to a full pro-
sees of botany.

R. C. F. HEGELMAIER, professor of botany at the University of Tiibingen,
ae died at the age of 72 years.

Proressor L. M. Unperwoop, Columbia University, has received the
degree of doctor of laws from Syracuse University.

Dr. Franz BucHENAU, the well-known monographer of Junaceae, died at
Bremen, April 23, at the age of seventy-five years.

THE GeRMAN Boranicat Soctety has offered a a of tooo marks for a
monograph on polymorphism in the algae.—ScrENCE

Dr. D. T. MacDovcat has been elected a foreign member of Hollandsche
Matschappij van Wetenschappen, the Dutch Academy of Sciences.

PROFEssoR Bruce Fink, the lichenologist, of Iowa College, has resigned to
accept a professorship of biology in Miami University, Oxford, Ohio.

R. FRIEDRICH CzaPEK, of Prague, has been appointed professor of botany
and oe of the botanic garden and institute of the University of Czernowitz.

PRoFEssoR GEORGE MACLOsKIE, Princeton University, has retired from
active service, having been appointed Professor Emeritus. He has been in
charge of the botany of that institution since 1875.

BoTANICAL APPOINTMENTS confirmed recently by the trustees of the Ohio
State University are as follows: Rospert F. RIGGS, assistant professor;
FREDA DETMERS, instructor; and L. A. HAwxnns, fellow.

PRrorrssor Conway MacMitran has resigned the professorship of botany
at the University of Minnesota and will devote his attention to business. The
Position is to be filled by promotion from the present staff.

Proressor D. H. Scort’s presidential address before the Royal Microscopical
Society, entitled “Life and Work of Bernard Renault,” is published in Jour.
Roy. Micr. Soc. 1906: 129-145, with an excellent portrait.

Howarp S. Rep, instructor in botany at the University of Missouri, has
resigned his position to accept an appointment in the Bureau of Soils, United
States ibaa og: of Agriculture. H. L. SHANtTz has been appointed to
succeed him

79

80 BOTANICAL GAZETTE [rory

THE EIGHTH annual session of the biological station of the University of
Montana will be held at Flathead Lake from July 11 to August 16. This sta
combines the advantages of lake, plain, and mountain. Botany is in charge
Tuomas A. Bonser, of the Spokane high school.

His ASsociaTEs on the faculty of Brown University lately presented to P. o- 4
fessor W. WHITMAN BaILEy a loving-cup, in token of their esteem for him per-
sonally and in commemoration of his twenty-nine years of active service, from
which he retires this year. Ata meeting of the trustees at Commencement h
was appointed Professor Emeritus.

Mrs. J. H. ScHarrner, of Columbus, Ohio, died recently after a brief illn
This is not only a sad loss of a devoted companion to Professor SCHAFFNER, bu
a botanist of promise and ability has passed away. Mrs. SCHAFFNER had pu
lished little, perhaps only one paper, over her own name, but a piece of com
pleted cytological work will soon appear as a posthumous paper.

IN THE Generalversammlungs-H eft closing volume 23 of Ber. Deutsch. Bot
Gesells., the following biographical sketches are published: WiLHELM SCHWACKE,
by TH. Lorsener; Epuarp TAnct, by G. HABERLANDT; JOHANN ANTON
Scuipt, by E. Prirzer; Orro Wtnscue, by J. ABRoMEIT; FEDERICO DEL:
PINO, by O. Penzic; Lo ERrrera (with portrait), by E. pe WiLpDEMAN.

AT THE REQUEST of some members of the American Medical Association
HERMANN VON SCHRENK made a pathological exhibit at the recent meeting
this association in Boston. The exhibit showed types of some diseases of ple
and some of the conditions producing these diseases. The manner of infec
and spread of disease, the symptoms and causes, the methods of treatment 2
of investigation were illustrated. The time for securing the material was extreme-
ly limited, but nevertheless the exhibit occasioned much surprise to the medi
men, though it showed but partially the work which plant pathologists ha
accomplished.

publication accompanying the title pages of the volume. On p. vi, line
for June 30 read July 7.

Editors: JOHN M. COULTER and CHARLES R. BARNES __

CONTENTS _

- The Nascent Forest of the Miscou Beach nc: Plain’ : WR

iologically Balanced Solutions for Pl

The Botanical Gazette

A Monthly Fournal ele all ide olan’ of Botanical Science

dited by JoHN M. CouLTER and CHARLES R. BARNES, with the assistance of other members of the
otanical stall of the Universige of Chicago,
ol, XLII, No. 2 Issued August 30, 1906

CONTENTS

-HE NASCENT FOREST OF THE MISCOU BEACH PLAIN. ConTRIBUTIONS TO THE
EcoLoGicaL PLANT GEOGRAPHY OF THE PROVINCE OF NEW BRUNSWICK. No. 4 (WITH
FOURTEEN FIGURES). W.F. Ganong - - - - 81

i E DEVELOPMENT AND ANATOMY OF SARRACENIA PURPUREA. CoNTRIBUTIONS

: FROM THE BOTANICAL LABORATORY OF THE JOHNS HopkKINS UNIVERSITY. No. 5

(WITH PLATES III-V). forrest Shreve - - “107

THE IMPORTANCE OF PHYSIOLOGICALLY BALANCED SOLUTIONS FOR
PLANTS. W. /. V. Osterhout ‘ 127

HE APPRESSORIA OF THE geo Leeiane okt i CONTRIBUTIONS FROM THE HULL
BOTANICAL ied LXXXIV (WITH SEVEN FIGURES). Heinrich Hasselbring 135

RIE FER ARTICLE.

NEREOCYSTIS ack: (WITH ONE FIGURE). Theodore C. Frye

: “the

Two New Species rrom NORTHWESTERN AMERICA, J. M/. Greenman - : - 146
URRENT LITERATURE,

MRR eG Se ee Se ee se - 148

PLANT RESPONSE

_ MINOR NOTICES - ee og) DCRR hes ele me eaemiin ome we Chae Tee

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VOLUME XLII NUMBER 2

BOTANICAL. GAzetTes

AUGUST, 1906

THE NASCENT FOREST OF THE MISCOU BEACH PLAIN.
CONTRIBUTIONS TO THE ECOLOGICAL PLANT GEOGRAPHY
OF THE PROVINCE OF NEW BRUNSWICK, NO. 4.?
W. F. GANONG.
- (WITH FOURTEEN FIGURES)

THE extreme northeastern angle of the Province of New Bruns-

wick, as the accompanying map will show, is formed by the island
of Miscou. The northwestern margin of this island is an extensive
sandy beach plain, growing rapidly by action of the sea, locally
called Grande Plaine. On this plain there is developing a forest
which exhibits every stage of formation from the salt plants of the
open sea beach to the heterogeneous vegetation of the mixed wocds.
The conditions are unusual and the phenomena of proportional
interest. In August 1905 I was able to give the place some two
weeks of observational study, with results which follow.
; In all such studies as this the ccrrect identification of the plants
Is of first importance, and identification is becoming a matter of
such difficulty that only a professional systematist is competent
authority. Accordingly I have sent all cf my collecticns, including
a specimen of every plant I found at Grande Plaine, to Professor
M. L. Fernatp, of the Gray Herbarium of Harvard University,
who has been so kind as to determine their identity, and, as well,
to give me the names they should bear in accordance with the recom-
mendations of the Vienna Congress. I wish here to express my
indebtedness to him and my best thanks for this invaluable aid.
Such is the origin of the nomenclature of this paper.

"No. 3 is in the Bor. Gazerre 36:1617186, 280-302, 349-367, 429-455- 1903-

81

82 BOTANICAL GAZETTE [auGuUST

As to previcus literature of this particular subject, there is
none. In 1886 Dr. G. U. Hay made a collection of Miscou plants
for the Geological Survey of Canada, but no account of them
was ever published, and no other botanist has heretofore been on
the island. In many respects, however, as the reader will observe,
the vegetation of this beach plain resembles closely the vegetation

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Fic. 1.—Outline map of part of the Gulf of St. Lawrence, to show the geographical
position of Miscou Island. S

of the sand beaches and dunes of Lake Michigan as described in
Cow Les’s well-known memoir,? and many of the conclusions of
that work are also applicable here. :
Grande Plaine extends along the west side of Miscou. Begi®
ning on the south at Eel Brook, (see the accompanying map, fig. 2)

2 Bor. GAZETTE 27:95-157, 167-202, 281-308, 361-391. 1899.

1906]

GANONG—NASCENT FOREST OF MISCOU. BEACH

8

a

ro]

where it is but a few yards wide, it rapidly broadens northward
until it reaches some half a mile across, and then narrows

again towards its northern
end, which is also the
northernmost point of the
island. Though nearly
level as a whole, it is by
no means flat, for it is com-
posed of a series of ap-
proximately concentric dune
beaches, which, two or three
in number at Eel Brook, in-
crease to over forty opposite’
Lac Frye. In height these
dune beaches vary from
two to five or six or even
seven feet (0.6-2™) and in
breadth from eight or ten
up to forty or fifty paces.
At its widest part, which
comprises some thirty or
more of the beaches, new
ones are plainly being
rapidly added, while at its
northern end the entire
plain is being washed away
by the sea, which is cutting
sharply across the ends of
the old beaches. About
two-fifths cf the plain, in-
cluding the older parts next
the upland, are forested;
about two-fifths, including
all the outer and newer
parts, are open, clothed only

by the waving beach grass ;

ii
Bay Chaleur ee
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fii! sea 8 eS > \
in Priyt td a — = S
brett En SES
itty SSE
fn arya ota = =
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yt napogeegs = SS
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1! ty oe ge ET.
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hte gilts Pepa Ee:
Tr aes SBI= Sie os
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wnt eae Sv SS
vu ye - oe = = :
iyi saQOOSUS > °* ° "Grande
il Baw= SS Plaine
v1 hse Soe
rp beg’ Ut I; =a SE =
pitt UP S E =.
Ad SS oo hob
Try gh oa ae =
ith ly peg i a aan by
4 epee = as =
enisi pea .
ayy (oS
tt ee
up 2seSs
ray : Vie ite ,
Ure | ee
rh Yess = =
I yg Ye er
4g B23 %
'"R/! bo et Sala
it fie +f = 2 =
1, 149), ej ea Je
Hs eae
Biiey sae
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hy hi QTASS plain Hy.
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wh Ft
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hy ;
My Scale —
el Brook Is mile = inch

Fic, 2.—Map of Grande Plaine, Miscou Island; from an amateur survey by the author; dotted boundaries are only

the intermediate zone, a small one-fifth of the area of the plain, is

f@ approximate; the heavier dotted line outside the swales represents approximately a line of higher dune beaches

84 BOTANICAL GAZETTE [AUGUST

transition zone where the forest is pushing its advance into the cpen
ground. The mode of formation of this remarkable plain, invcly-
ing the anomaly of extensive land-building on a sinking coast, I
have described somewhat fully elsewhere. Briefly, the facts are
these. As the result of peculiarities of the topography, wind,
and tides of this region, there is formed on the shallow north-
western side of Miscou a kind of great eddy in which all movable
materials, sand and gravel from the wear of the rapidly crumbling
adjacent coasts, as well as driftwood, waterweeds, and cther
flotsam, often from a great distance, tend to collect, and thence
are driven ashore by the prevailing westerly winds. Formerly the
island extended farther north than now, carrying with it both eddy
and plain; but the general subsidence actively in progress in this
region has carried its low northerly end beneath the sea, thus fcrcing
the eddy and the accompanying plain-building gradually southward.
The northern end of Grande Plaine today is being rapidly washed
away (compare map), to be redeposited farther south, and the plain
as a whole is thus rolling by its outer margin southward along the
coast. The subsidence of the land has produced another effect
upon the plain, and one of considerable consequence to its vege
tation, namely, its inner and older part averages somewhat lower,
that is, less above sea-level, than the outer and newer part, thus lead-
ing to a settling of water towards the older inner parts, and a rela-
tively higher water-table in them. That we have here a beach plain,
instead of a series of lofty sand dunes, is the result of the fact, app@™
ently, that the dry sand of the beach is blown ashore no faster than
the beach grass can fix it. At both the northern and southern ends
of the plain, however, there is some approach to a building of
true, though low, dunes.

My brief study of the vegetation of Grande Plaine was entirely

observational, not at all instrumental, nor do any metecrologic#l

or other exact physical data for this region exist. Grande Plame —

lies at sea-level in latitude 48°, beside a shallow sea, warm in summer

but frozen over in winter. The summer climate is rema

equable, of a temperature most comfortable for man, with no fogs

and but little cloudy weather. The rainfall must be not far from
3 Bull. Nat. Hist. Soc. N. B. No. 24:453. 1906.

i ee

el Sinlg

rkably —

eee

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 85

45 inches. Heavy winds from the west prevail in summer. The
soil is of pure quartz sand derived from the wear of the gray carbon-
iferous sandstones of the region, this sand having, of course, the
usual relations to water-supply, mineral nutrients, etc. No other
special factors with a bearing upon the vegetation appear to be
prominent.

We turn now to consider the vegetation. Although it presents
every gradation from humble herbs of the open beach to the densest
woods, nevertheless the eye becomes accustomed to recognize, and
the speech to designate, certain definite vegetational regions. These
represent the modes or climaxes, as it were, in the vegetation curve
—the parts which exhibit a distinctive character in the physiog-
nomy of the whole. They are the following: (1) the new beach,
(2) the grass plain, (3) the swales, (4) the sandy woods, (5) the
closed woods.

THE NEW BEACH.

The characteristic open, or new, beach of Grande Plaine, the
kind which best illustrates the mode of growth of the plain, is to
be found opposite its middle and broadest part; for towards the
northern and southern ends its structure is modified by local condi-
tions of erosion and dune-building. Outside of all is a broad sloping
inter-tidal beach of pure sand without vegetation (fig. 3). Above
It is the narrow band between ordinary and extreme high tides,
from which the drying sand is being driven landward by the winds;
it is also vegetationless, or with but stragglers from the upper beach.
Finally, there is that broad shelf, very well shown in the accom-
Panying photograph (fig. 4), reached only by the very highest tides,
Composed of fine quartz sand, intermixed with some gravel and
occasional flat cobbles; it is covered with scattered driftwood among
and over which the dry sand is being forever driven, shifted, and
piled, Thus the new beach offers a barren habitat to plants, for
it has a mineral-poor soil, drenched often by salt, forever shifting,
and exposed to the unbroken force of frequent heavy winds. The
vegetation is plainly responsive to these conditions. It is extremely
Scanty, the plants growing widely isolated, while many square
yards do not show any vegetation at all. Thus competition among
the plants seems not to exist, and the struggle is wholly with the

86

BOTANICAL GAZETTE

[AUGUST

physical environment. The mest characteristic plant by far is
the small, radiate-decumbent, succulent, annual saltwcrt, Sadsola

~

Sandy Woods Closed Woods: Upland

Swale

4

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Kali, which occurs but rarely and for the most part i

d the distribution of its

in, an

:

the line AB is true level, and may be taken to represent approximately the position of the water-table.

.

Fic. 3.—Idealized section and map to show the mode of formation of the beach pla
vegetation;

n the lee of

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 87

some shelter, such as a hollow or large piece of driftwood. Next
in abundance, though but scarce, is the little fleshy, rosette-like,
annual sea rocket, Cakile edentula (C. americana). Third in abun-
dance is the low halo-rosette, perennial sea lungwort, Mertensia
maritima, here seemingly growing as an annual, also mostly in
places of some shelter. Rarely, and then only in a sheltered position,
occur tiny radiate-creeping plants of the beach pea, Lathyrus mari-
timus, growing apparently only as an annual, and sometimes show-
ing a marked difference in the windward-creeping and leeward-

Fic. 4.—Typical open, or new, beach, looking north; among the driftwood occur
Scattered tufts of saltwort and beach grass.

creeping shocts on the same plant, the former being much shorter
and smaller-leaved. Even rarer is the radiate-creeping, small-
leaved, halo-scurfy annual, Aériplex patula hastata. Here and
there, however, especially in sheltered places, arise the tufted culms
. the beach grass, Ammophila arenaria, the characteristic sand-
binding perennial of the dune beaches next to be considered, here
seemingly growing from seed. I was able to find no other plants
on the new beach. Thus we see that this vegetation is distinctly
adjusted to the physical conditions, for it is of great paucity, of small
and slow growth, annually renewed, closely ground-appressed, and
Strongly xerophytic.

88 BOTANICAL GAZETTE [AUGUSI

THE GRASS PLAIN.

Inside the line of open beach begins the sand plain, composed
of a great number of approximately parallel dune beaches, forming -
smoothly swelling ridges and hollows of elevations and breadths
already described. Every dune beach, I believe, originates with
a core of driftwood. As the tidal beach is built outwards by the
addition of sand, driftwood continues to collect on its uppermost
part, until finally some unusual combination of great winds with
high tides sweeps it up beyond reach of further disturbance. Then
the driving sand from the beach is caught among it; the beach
grass gains a foothold in the sheltered places, spreads, and checks
the further movement of this sand. Then more sand is driven
shoreward, and it grows into a low dune which is fixed by the beach
grass as fast as it rises. The limit is reached only when a new line
of driftwood has been formed outside and begins to stop the sand
for its own growth. The resultant dune beach offers severe condi-
tions for plant life, for its surface is swept, especially on the summit
and windward slope, by heavy winds; it is heated intensely by the
sun; it is readily movable; and it forms a soil extremely poor in
mineral nutrients.4 It lacks the salt of the newer beaches, however,
for this is soon removed by the rain; and it possesses an ample
supply of moisture a foot or two beneath the surface, for the supply
brought by the rain drains but slowly away, owing to the low gradient
of the water-table. These conditions, especially at their extreme
on the summits and windward slopes of the beach dunes, are endured
by practically but a single plant—the herbaceous-perennial, sub-
terranean-creeping, xero-culmed, deep-rooting beach grass, Amm0-
phila arenaria, which occurs, without any competitor whatevel,
in open scattered tussocks, only partially covering the ground, 4s
well shown in fig. 5, and in closer view in figs. 6 and 7. It happens
that this grass is of considerable economic value to the neighbor
ing farmers, who cut it and haul it for hay, and whose cattle graz€
upon it; its destruction in this way causes an irregular exposure
of the outer beaches, permitting them to be irregularly cut by the
wind. It is for this reason, I have no doubt, the newer outer beaches

4 As indicated by KEARNEY’s recent studies: Bot. GAZETTE 37:426-436
1904.

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 89

are so much more irregular in their various characters than the
older inner beaches, which antedate the advent cf man.

But while the beach grass has no competiter, it affords a shelter,
especially behind its tussocks, permitting the growth of a number
of other plants, which, however, form but an insignificant part of
the entire vegetation, and which are widely separated from one
another. Most important of these, perhaps, is the beach sedge
Carex silicea, which grows in scattered tussocks here and_ there
among the beach grass, and it is indeed the only other plant which

ers a ‘ ae “xCe
Fic. 5.—Ty pical grass plain, looking north; practically no plant visible except
the beac h grass.

seems at home in this situation. The remainder of the plants, all
sparsely or rarely represented, are obviously stragglers from the
most diverse hal bitats, many of them quite unexpected residents
in such a situation. Thus, dwarfed saltwort strays in from the
beach, and the beach pea is here somewhat more flourishing than
on the open beach. Then there are greatly dwarfed individuals
of certain ubiquitous. forms able to endure a wide range of physical
conditions, such as the dandelion, Taraxacum officinale, w hich extends
in sheltered spots even to the outer margin of the plain; the’ Canada
thistle, Cnicus a vensis; the sow thistle, Sonchus arvensis; the

90 BOTANICAL GAZETTE [avousr

field sorrel, Rumex Acetosella, in dwarfed-rcsette, very red forn
the evening primrose, Oenothera biennis; and the moonwort, Bor y-
chium ternatum intermedium. There are also some forms usually
characteristic of rather a dry habitat, such as the pearly everlas
Anaphalis margaritacea, and a western yarrow, Achillea lanulo:
In addition there are cthers, generally in more sheltered spots al
also greatly dwarfed, which usually prefer a moister habitat, su
as the two western roses, Rosa acicularis (R. Sayi, R. Engelmans
and Rosa lucida; a western viclet, Viola adunca; a stitchwort, Sh
laria longipes laeta; a silver weed, Potentilla Anserina conc
the stellate false Solomon’s seal, Smilacina stellata; and on
the vetches, Vicia Cracca.s The great diversity of natural b
of these plants, their scanty and irregular occurrence, and
dwarfed size and rosette-forming tendency all unite to show |
none of them are here at home. Obviously they are the ones V IC
of all the many kinds which must be brought to this plain by natural
modes of dissemination, are sufficiently tolerant physiologic
be able to germinate under, and then to withstand, these extren
physical conditions, eking out here a starved and precarious.
ence. The conditions for germination upon the sand must
extremely severe, and it is very likely that other kinds of ple
could exist here as adults, could their seeds develop; and |
it is probable that the individuals which do exist on the plain
those whose seeds happened to fall in especially favorable
or became properly buried by the moving sand. Else why 4
they so few? The universal dwarfing is due in all likelihood n¢
to the heat and dryness of the surface, nor to any salt conteél
in the soil, and certainly not to a scarcity of soil water, but to
the paucity of mineral nutrients in the sand. This is in harmony
with another feature they mostly show in common—very
and, I think, much-branching roots. The fact that they* com

5 The following Grande Plaine plants appear to be new to the flora of New B

wick: Achillea lanulosa, Viola adunca, Rosa acicularis, Stellaria longipes laeta,
Potentilla Anserina concolor. Certain others are new in name, the species having

form to the rules of the Vienna Congress, but in these cases the names of Gray’ s Mow
ual, 6th edition, have been given in brackets

1906] GANONG—NASCENT FOREST OF MISCOU BEACH QI

from such a diversity of natural habitats, and yet live in this peculiar
situation upon an equal footing, shows how far we are from under-
standing the real bases of physiological adaptation, and further
shows that in the study of the physiological life-histories of plants
lies the most important and attractive field for the ecologist of the
near future.

So much for the expcsed parts of the dune beaches. But in
addition they offer, upon their inner or leeward slopes and in the
hollows, situations more sheltered, not so much from the sun, since

Fic. 6.—Typical hollow between outer dune beaches; the tall grass is all beach
grass, but the small plants among it are the common strawberry.

their average course is nearly north and south, but from the westerly
winds. The older inner dune beaches also are protected to some
extent by the newer outer ones, as well as by their slightly lower
average level. The difference between leeward slope and hollow is not
simply one of degree of shelter, however, but also of physical condi-
tions, for the hollow is much nearer the source of water supply,
the free table of which is not over a foot or two beneath the surface.
In consequence of these differences we can recognize three distinct
phases of vegetation: first, a larger development on the leeward

92 BOTANICAL GAZETTE [avcust

slopes of plants which are small and rare on the outer slopes; seco id,
a distinctive vegetation of the hollows; and, third, a distincdll
vegetation of the inner slopes. 4

As to the first phase, it is enough to note that several plants,

and scattered on the outer slopes, become larger, frequent,
even patch-forming on the inner; and this is true also in less deg
of other species. The beach grass persists in all situations. :

The second phase is the vegetation of the hollows. The very
first plant to appear in this situation, and that too near the o ter
beaches, is always, strangely enough, the common wild strawbe
Fragaria virginiana, apparently of normal size and form,
ingly quite at home, and spreading abundantly by runners, so
it forms considerable patches. The appearance of the nas

appreciable density, such that they afford a cover to the ground, ’
turf-forming grasses, of which the first is the red fescue, Festi

of course, is one of the most tolerant, and hence ubiquitous, her
of our flora, and its situation here is partially explained by the nea
ness of the abundant water supply. Yet it is surprising to
it taking so important a part in a vegetation in so peculiar a posi

The third phase of this vegetation is that characteristic of
sheltered slopes. First of such plants to appear, and the mo
common and characteristic, is the dwarf creeping juniper, J unip-
erus Sabina procumbens, of which single plants originate just below
the beach dune crests, and creep radiating, more to leeward than
to windward, in a close dense mat covering many square feet. A
young plant es shown in fig. 7, in characteristic form and positigis .
On the inner beaches these plants occur upon the outer as
as the inner slopes, and the shelter of the mats thus formed affords
in reality the principal starting-point for the development of other
plants which lead gradually to the development of the forest, as
will be noted under the transition vegetation. In a similar situation,
but independently, arise patches of two other characteristic
plants, a bright-green, leathery-leaved, tufted shrub, the wax berry,

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 93

Myrica carolinensis, which comes to form dense discoid (sometimes
almost fairy-ring like) masses on the crests and inner slopes; and
the less frequent, low, dense-tufted, white-hairy shrub, Hudsonia
tomentosa, in irregular close patches. All of these plants are pro-
nounced xerophytes, which amply explains their ability to live in
this situation, and even their preference for the somewhat drier
upper slopes of the dune beaches. Their xerophilism, in common
with that of many other evergreen sand plants, is, as I guess it, an

Fic. 7.—Typical upper inner slope of a dune beach; the grass is beach grass, but
6
in the center is a typical plant of dwarf creeping juniper.

adaptation to he physiological dryness which results when, as
must often be the case in spring and fall, the ground. water is of
low temperature and hence slowly absorbed, while the leaves are
€xposed to high transpiration conditions from the bright sun, heat
reflected from the sand, and high winds.® The juniper, while
perfectly at home here, apparently is so only through coincidence,
for its original habitat is seemingly dry rocky hills. But the other

° This principle, which from its discoverers we may call the Kra~mMan-GOEBEL

Drincinia
Principle, seems to me dese srving of much more recognition than our students are

in
nclined to give it. At least it calls for careful experimental investigation.

94 BOTANICAL GAZETTE [auoust

two, the waxberry and the Hudsonia, are characteristic of just this
situation, in and to which they have apparently been adaptively
developed. Towards the inner dune beaches another low shrub
comes in on the slopes, though dwarfed and not abundant, the
common blueberry, Vaccinium pennsylvanicum; it is evidently
not here at home, but its somewhat xerophytic habit permits it to
exist. As these various plants grow older and extend their patches,
they run together more or less, sometimes two, sometimes three,
and even all four. Later others are added to them, initiating the
juniper mats and the woods carpet, later to be considered.

The contrast between the vegetation of the outer and the shel-
tered slopes of the dune beaches comes out with striking clearness
a few hundred yards north of Eel Brook, where it happens the entire
plain is very narrow, and slopes in both directions from a central
higher crest. Outside of this can be seen only the beach grass and
its accompanying forms as listed above, while inside the various
xerophytic shrubs show to great perfection.

THE SWALES.

Between the cpen grass plain and the woods occurs a transition
zene marked not only by an intermediate vegetation but also by
distinctive physical features as well. First of all it is characterized
by the presence of several great turf-carpeted and tree-bordered

swales, morpholcgically hollows between the dune beaches which

here spread much farther apart than usual. They are well show?
in figs. 8, 10, 11. They are best developed in the widest part of the
plain, hardly cccurring towards its southern or northern ends, and
outside cf them runs a line of higher dune beaches, which indeed
can be traced through most or all the length of the plain (jig. 2).
The swales are narrow southward, but broaden northward, deepening
as they go, until in some cases they dip beneath the water-table
(thus exhibiting pools), after which they rapidly narrow and ms¢
to disappear northward. Again, the trees of this zone, occurring
always along the slopes of the dune beaches, do not exhibit a trans’
tion of size and age to those of the sandy woods, but are alway>
so much smaller and younger as to be sharply marked off from them,
the case shown in fig. ro being very exceptional, and that of 7+ 8

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 95

more typical. Again, the transition from the broad swales to the
beaches of the sandy woods is most abrupt, for the latter are regular,
narrow, close together with scarcely any hollows between, and
also exhibit a curious barrenness on their summits in marked con-
trast to the better-clothed summits farther out (compare jigs.

and 13). Unfortunately the full importance of these features did
not strike me in time for a study of them on the ground, but such
data as I possess in notes and maps lead me to believe that the swales
are much newer in origin than the beaches immediately inside them,
and that they mark the transition from an older series of beaches
which formed part of the original Grande Plaine extending far to

Fic. 8.—Typical transition zone, looking north; showing a swale on the right,
with its sharp line of transition to the woods; the trees are all white spruce.

the north of the present island, and a newer series formed by the
rolling of the plain down the coast, as described earlier in this paper.
All the facts I possess both as to geography and vegetation are con-
sistent with this view.”

Aside from the question of age, the swale zone differs physically
from the grass plain by its greater shelter from the west winds, its
lower level and greater nearness to the water-table, a probable
increase of mineral nutrients derived from decaying driftwood and
diffusion from the upland, and some slight accumulation of humus.

ee ede Fay ee ee

7 And it is sustained by the tradition of the residents who say that the plain has
been built out from the edge of the woods almost within the memory i. men still
living. I have discussed’ the subject more fully in Bull. Nat. Hist. Soc. N. B. No.
24:456. 1906

96 BOTANICAL GAZETTE [aucusr

The vegetation consists broadly of a higher development of the
vegetation of the inner grass plain—the scanty turf of the hollows”
becoming the broad expanse of meadow turf of the swales, and—
the juniper mats extending greatly with the addition of many young —
nn
white spruces. So distinct are the turf of the swales and the juniper —
mats, with their trees, from one another, that there result glades
and vistas of park-like and charming aspect, as shown especially —
well in jig. 8. 3
First in importance are the juniper mats, for they inaugurate
the woods. These mats, composed either of large radiating patches
of this plant, or else variously united and combined with pate
of waxberry, Hudsonia, and blueberry, extend greatly in diamete
covering the crests as well as the slopes of the dune beaches,
thus form a woody net in the shelter of which several other form
mostly markedly dwarfed, gain foothold. A typical example
shown in fig. 9. Some of the plants of the grass plain persis
especially the beach grass, pearly everlasting, and yarrow. 1
new forms which appear are, first of all, the common crowberry, #
peirum nigrum, and the rock cranberry, Vaccinium Vitis-Idaea mt
fcllowed closely by the three-toothed cinquefoil, Potentilla triden
all of them plants characteristic of dry upland rocky situations
Less frequent are the little gentian, Gentiana Amarella acuta, and
the large cranberry, Vaccinium macrocarpon, plants belonging |
moist places. And when the mats are especially well developed
there come in, as shown in fig. g, the reindeer lichen, Cladomia —
rangifera, and a brown moss which I take to be the Aulacomnium
palustre (so much more highly developed in the woods), another
curious mixture of xerophytic and hydrophytic forms. We have
therefore upon these juniper mats a very heterogeneous assem
blage of forms drawn from diverse natural habitats all the babs
from rocky hills to bogs. They do not exist here, therefore, ™
virtue of adaptation to this position, but plainly represent thos
forms of the flora of this region whose adaptations happen to ;
these conditions, or whose range of physiological toleration happe*
to be great enough to permit endurance of the conditions here. ©
these matters we shall know more in the future, but their mention
helps to emphasize how large an element of accident or incident

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 07

there is in adaptation, and how likely it is that adaptation will
ultimately prove to be a matter of the loose and large rather than
of the exact and minute.

Finally, it is in this same situation, upon the upper slopes of
the dune beaches, and usually, but not always, on the juniper
mats, that the characteristic trees of the zone, the white spruce,
Picea alba, develop. Standing in open formation, they do not
interfere with one another’s growth, and in consequence become,

q : ‘
BS Pan ie ae A nen

Pre 9.—Typical large juniper mat on a slope and crest of a dune beach, with a
number of associated plants noted in the text; looking south.

except for wind effects, symmetrical in outline and clothed to the
ground. They cccupy that situation no doubt for the same reason
that the shrubs do, as a compromise between the greater wetness
of the hollows and the greater dryness of the beach summits. This
habit of growing thus upon the slopes, and not on summits or hol-
lows, has a most important effect upon the physiognomy of the
vegetation in this zone; for to it is due the openness of the swales,
with their regular borders of trees, and as well the openness of the
beach summits in the sandy woods later to be noticed. Toward
the sea the spruces are small and dense, and often show, as in fig. 11,

98 BOTANICAL GAZETTE [AUGUST

pronounced wind effects. In places many seedling trees may be
found, though the distribution of these is curiously irregular. In
one place only did I find any other tree, and that was a single speci-
men of the prince’s pine, Pinus Banksiana.

If it be asked why the white spruce is the first tree to develop
on these plains instead of some other of those growing on the upland
near by, I can only say that an answer must wait until we know
something about the physiology of the white spruce and of other
trees of the vicinity.

We turn next to the swales, those long open hollows carpeted
by a close turf, and bordered by spruces. The general appearance

Fic. 10.—Highly developed swale, looking south; on the left is the edge of _
sandy woods with old trees, and on the right a line of much younger trees, here muc
larger than usual.

of the turf is well shown on the right in fig. 8, and extremely well
in jig. 10, which shows perhaps the best-developed of all the swales.
The turf is a good deal modified in vegetation by the grazing of
cattle and horses, yet its general characters show plainly enough
Originating in the outer hollows with the strawberry, as alrea®y
noted, the real turf begins with the red fescue grass, Festuca rubra
(Ff. ovina rubra), which soon drives out the strawberry. To this, * Z
becomes compact in the inner hollows, other grasses are rapidly
added, especially the June grass, Poa pratensis, and then the brow?
top, Agrostis alba. After these comes a rush, Juncus Vaseyi, 2
the little sedge, Carex Oederi. Very likely, also, there are other

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 99

grasses which, owing to my imperfect knowledge of those -groups,
I overlooked. On and among these plants occur others, among
which I have collected the following: the eyebright, Euphrasia
americana (E. officinalis); the bugle weed, Lycopus uniflorus (L.
virginianus); a tiny everlasting, Antennaria neodioica; a pearlwort,
Sagina procumbens; the plantain, Plantago major; the two common
cinquefoils, Potentilla norvegica and Anserina; the fall dandelion,
Leontodon autumnale; and the white clover, Trijolium repens.
These forms, in commen with the grasses, are all greatly dwarfed

Fic. 11.—An outer swale, looking north; in the center clumps of blue flag; on
the slope on the left white spruce and waxberry; on the right is a low depression with

a thicket of poplar (the white spruce among it, being on ee elevation).

and derived from diverse habitats, and are evidently a collection
of heterogeneous stragglers from the neighborhood, held together
by no stronger bond than ability to eke out existence in this inhos-
pitable position. The majority belong to somewhat moist places,

and they find an ample supply of water; for the water- table even
in the driest summer is within a foot of the surface, and of the
sweetest water. E vidently it is not dryness which stunts the forms,
but most likely, as I believe, paucity of mineral nutrients. The
turf represents the first closed formation we have met with, and

I0o BOTANICAL GAZETTE [AUGUST

competition may therefore determine some of its minor features,
but to these I gave no attention,

The turf reaches its climax in the open swales like those shown
by fig. ro. In the woods it disappears, as will be noted under the
next section; but towards the lower levels, especially towards the
pools of standing water, it gives way gradually, by definite steps,
to an assemblage cf true swamp plants. The very first of these
to appear in the lcwer places in the swales is always the common
blue flag, Iris versicolor, and characteristic scattered clumrs of
this plant may be seen in the fcreground in fig. 11, in the distance

farshy swale, looking south; in the center a permanent pool with
margin ‘saibea’ oN cattle; behind it are cat-tails and rushes, and back of them a thicket
of poplar; on both right and left is sweet gale, and in the foreground is the blue flag-

on the swale in jig. 8, and cn the left margin of the swale in jig. 12
Next follows always the sweet gale, Myrica Gale, and after that
low bushes of the balsam poplar, Populus balsamijfera, a plant which
forms very dense thickets and grows larger as the situation is more
sheltered. Finally the pools of standing water are reached, and
on their margin cccur cat-tails, rushes, and mare’s tail, Hippuris
vulgaris, with some other forms which I have not attempted. esp&
cially to study. The plants may be variously combined according
to local circumstances, but a very typical arrangement is shown in
fig. 12. It is plain that we are dealing here simply with an ordinary

r:
a

1906] GANONG—NASCENT FOREST OF MISCOU BEACH IOI

swamp, offering nothing peculiar unless it be the small size of
some of the plants, notably the poplar. But these places develop
yet farther in time, and there come in after the poplar three willows:
Salix balsamijera, S. lucida, and S. candida, forming very dense
thickets, and apparently under congenial conditions. Finally comes
in the alder, which appears to be mostly a form of the green alder,
Alnus mollis, giving us the culmination of the swale thickets.

THE SANDY WOODS.

Inside the swale zone, through almost the whole length of the
plain, extends a narrow zone, only some four or five dune beaches

Fic. 13.—Typical sandy woods, just inside the swales, looking north; in the cen-
ter a dune beach, bearing scanty beach grass and reindeer lichen, while on the slopes
are small juniper mats with white spruces.

wide, of remarkable sandy woods, whose characters are well shown
by fig. 13. Their most striking feature is perhaps the relative bare-
ness of the tops of the beaches, which remain far more clear of vege-
tation than do most of the beaches outside of them; and this bare-
ness, in conjunction with the presence of trees on the slopes and in
the hollows, gives rise to curious vistas as shown by the photograph.
The bareness must have some physical basis, but I was not able
to discover it. These dune beaches, further, are very narrow, low,
and regular, with hardly any true hollows between, so that the turf

102 BOTANICAL GAZETTE

earlier given, that there is an abrupt physical difference be
the beaches of these woods and those outside, a difference w
I feel sure, is one of age. The position of the zone would in

mineral supply, and shelter than the zone outside, with wh
large size of the trees is in agreement. But the bigness of
makes the barrenness of the beaches all the harder to expla

mats in the slopes and hollows with their well-grown white spt
The mats, however, are no longer entirely creeping, for the j

send up numerous erect shoots. With them persist seve
plants from the transition zone, especially the rock cranbet
three-toothed cinquefoil, the pearly everlasting, and a few
But in addition new forms come in, especially and characte
the bearberry, Arctostaphylos Uva-ursi, a rocky-hill plant, here

carpet which we may best consider under the next section.
themselves are of moderate size, rarely if ever over 20 feet in

A fact of interest about the juniper mats, applying also to
degree to the forest mat which succeeds it in the closed woods,
its very slight hold upon existence on the sand, for where
cross and disturb it, the entire mat dies and soon disappears.
instability shows forcibly how hard are the conditions of life in
situation, and how narrow the margin between success and fail

THE CLOSED WOODS.

The climax of the sand-plain vegetation is reached in the ¢
though dwarfed mixed woods extending between the sandy woods
the upland. A typical view of the clcsed wocds is shown by iis.

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 103

Physically the situation is much more protected than the zones out-
side of it, and, lying at a still lower level, it has a moister soil. The
soil, however, is still of sand, though it contains some humus from
the decaying vegetation and must derive some mineral matter by
diffusion and drainage from the upland. Very likely also the sand
is shallower here than farther out (fig. 2), and hence some influence
of the minerals of the underlying soil may be felt, while in places
an appreciable enriching of the soil must result from the decay of

Fic. 14.—Typical closed woods, chiefly of white spruce, but with some deciduous
trees in the background; the closed forest carpet shows in the glade of the left fore-
ground.

the bodies of the walrus, formerly slain here in great numbers, as
manifest by their semi-fossil bones.’ These additional sources
of mineral nutrients, however, by no means furnish a supply sufficient
for the proper growth of the woods, for in every feature they exhibit
marked depauperation as compared with the same species on v3
neighboring upland.

In relation to the preceding zone, the closed woods consist essen-

® Described more fully in a note in Bull. Nat. Hist. Soc. N. B. No. 24:462. 1906.

104 BOTANICAL GAZETTE

opment, both in number and size, of the white spruce trees, to which
are added some deciduous trees and shrubs. And where the hollows a
dip lower than usual, and towards the upland in places, this forest
merges to alder and cedar swamp. 4

We consider first the woods carpet. Morphologically it is a —
direct development of the juniper mats of the outer zones, though —
but little juniper, aside from occasional erect shoots, is left. With
it persist some of its earlier associates, the rock cranberry, three-
leaved cinquefoil, some grasses, the bearberry, and the reindeer
lichen, varying in their respective development according to situa- 3
tion. To these are now added dwarf plants of the bunchberry, —
Cornus canadensis, the twin flower, Linnaea borealis americana, —
Pyrola chlorantha, the pipsissewa, Chimaphila umbellata, and an —
abundant brown moss, which has been identified for me by Mr.
A. J. Grout as Aulacomnium palustre, a typical swamp moss.
Upon this carpet develop a few larger forms, especially the abundant
wild sarsaparilla, Aralia -nudicaulis, the gooseberry, Ribes oxy-
acanthoides, the dwarf raspberry, Rubus triflorus, with others less
conspicuous.

We consider next the trees of these woods. First in importance
and size, far surpassing all others in both respects, is the white spruce:
It attains a height of perhaps 7.5™, a diameter near the groun
of perhaps 45°™, and it exhibits over 100 annual rings, though per-
haps some may be much older than those I counted, which were
cut by the residents for wood. The next to appear is the balsam
fir, Abies balsamea, becoming somewhat abundant and character-
ized by a spruce-like arrangement of its leaves all around the stems-
Then follow the red maple, Acer rubrum, the aspen, Populus trem-
uloides, the paper birch, Betula alba papyrifera (in very small trees
however), and the mountain ash, Pyrus americana; while the
common undershrubs are the red dogwood, Cornus stolonijera,
and the black alder, Ilex verticillata. There are probably scme
others, but these I believe are all that are notable.

In especially low places, such as in certain hollows, and at the
contact of plain and upland, the conditions verge towards those of

Te SSE eS a Tete me) | ia tote Rage ab tere rea ana pal LS SORE Se Renee ora)

PG eee Se ee Oe ee ee

ee ee ee ee Ms Ser

1906] GANONG—NASCENT FOREST OF MISCOU BEACH 105

a swamp, and swamp plants appear—the iris, the sweet gale, some
mints, species of Galium, and the dewberry; while the spruce gives
way to the white cedar, Thuja occidentalis, and the alder beccmes
abundant, forming a dense jungle. But this is of less interest than
the vegetation of the outer zones, and hence I gave it little study.

Thus it appears that these woods present no features, size of
the plants alone excepted, markedly different from those of woods
preponderatingly coniferous in the neighboring upland, and they are
evidently tending towards the typical woods of this region—the mixed
coniferous-deciduous forest.

We have thus another illustration of that principle so important
in physiognomic ecology, that vegetation, no matter under what
immediate physical conditions it may be, is always tending towards

a climax type, determined primarily by climate.

CONCLUSION.

In this paper I have tried to state the facts about the vegetation
of a somewhat remarkable place, adding thereto some ecological
comment whose chief value is to illustrate our ignorance of that
subject. As I understand it, such descriptions as this aims
to be may have three values. First, they can present to all who
have interest in such matters a series of pictures, as vivid and real-
istic as possible, of the vegetation of special places, and they are
the more valuable according as they are the more clearly and attract-
ively written and the more aptly illustrated. Second, they should
help to supply information, badly needed by all of our manuals,
about the natural habitats of the common or important species
of plants. Third, they can form storehouses of facts about vege-
tation upon which the future student can draw as the advance of
physiological ecology gradually makes possible an understanding
of the principles underlying physiognomic ecology. Such descrip-
tive work can be done to profit by the student whcse work is perforce
confined to his summer vacations, if he but bring to it time and
care enough; but he should be content to describe well and to leave
interpretation to the field physiologist yet to come. Speculation
cannot of itself advance knowledge, and it can bring a subject into
disrepute. It is only, I believe, through field physiology, the study

106 BOTANICAL GAZETTE [Aveust

in field laboratories of fundamental plant-dynamics, that ecologica
knowledge can really be advanced. And the dynamical problems,
as I see them, fall under these heads, in the order of importance
(a) physiological life-histories of species, (b) physics and chemistry —
of the soil, (c) nature of plant-competition, (d) a better correlation —
of meteorological data with physiological phenomena. :

SMITH COLLEGE,
Northampton, Mass.

THE DEVELOPMENT AND ANATOMY OF SARRACENIA
PURPUREA.* oe
CONTRIBUTIONS FROM THE BOTANICAL LABORATORY OF THE
JOHNS HOPKINS UNIVERSITY. No. 5.
FORREST SHREVE.
(WITH PLATES III-V)

THE work of which the results are here given was undertaken at
the suggestion of Dr. D. S. JoHnson, and has been carried out at the
Biological Laboratory of the Johns Hopkins University. I wish
here to express my thanks to Dr. JoHNson for much advice and
helpful criticism in connection with this work, and to express to
Professor Witu1am K. Brooks my appreciation of his interest and
encouragement, I also wish to thank my fellow-student Mr. SAMUEL
RITTENHOUSE for his kindness in gathering material for me during
my absence from Baltimore.

The material worked upon was obtained mainly at Glenburnie,
Maryland, near Baltimore. Most of it was fixed in the field; and
of several killing reagents tried 1 per cent. chrom-acetic and Carnoy’s
mixture were the most satisfactory. Preparations mere made by
ordinary paraffin method and stained with the Flemming triple stain
or with cyanin and erythrosin.

DEVELOPMENT OF THE FLOWER.

The earliest stage observed in the development of the flower was
in material gathered August 30. There are then to be seen the
primordia of the three bracts, the five sepals, and the five petals,
which have apparently arisen in the order named. Lying just
within the edges of the petals are the staminal primordia, as yet mere
papillae, and within them is a flat surface with slight elevation at
the center. A somewhat later stage than the last shows progress in
the development of the stamens, which now appear as ten groups of
protuberances lying in the position before noted (fig. 2). Each

« Dissertation submitted to the Board of University Studies of the Johns Hopkins

University for the degree of Doctor of Philosophy.
a] . [Botanical Gazette, vol. 42

108 BOTANICAL GAZETTE [Auaust.

group arises from a base which is distinct from the bases of the adjo
ing groups, and is made up of the primordia of five to eight stamens.
There is no suggestion of a pairing of the groups nor of their falling
in two whorls. Upon the central flat surface has arisen the ovary, ‘
which at its base is pentagonal in outline, and at its apex is s

to give rise to the placentae are upon the sides of the pentagon, whi
shows each placenta to be made up of the edges of two carpellary
leaves (figs. 2, 14).

MICROSPORANGIUM AND MICROSPORE.

destined to give rise to filament and anther. The latter portion —
bears approximately the same outline in cross section as do the q
mature anthers. The location of the archesporium is indicated at
first only by the slightly greater size of the nuclei in the region of 4
the four microsporangia (fig. 4), but soon comes to be more sharply
defined by the concentric arrangement of cells in the region of the —
future parietal cells. The archesporium is at this earliest recog
nizable stage about six cells in cross section, but grows rapidly to
about twelve ce'ls in diameter (fig. 5). Development proceeds in —
the autumn to the differentiation of the endothecium, the two OF
three parietal layers, and the pollen mother cells. There is yet 20
distinction of definitive sporogenous cells and tapetum. In thi
condition the stamens pass the winter.

The elongated parietal cells do not contribute to the tapetum,
but it is made up entirely from the isodiametric cells of the arche-
sporium. The outer outline of the tapetal layer is continuous,
the inner is irregular only to an extent which makes it in some places
two cells in thickness and in other places three. The cells of the
tapetum do not wander among the definitive sporogenous cells
Shortly after the differentiation of the tapetum, and before the pollen
mother cells are in the synapsis stage, the tapetal nuclei divide once
by mitosis, and so far as observed once only. At the time of tetrad
division the tapetal nuclei are enlarged, the chromatin is granular
and scattered, and the nucleoli are large. At the time of the forma

2

1906] SHREVE—SARRACENIA PURPUREA 109

tion of the walls of the pollen grain the cytoplasm of the tapetal cells
becomes much vacuolated and the nuclei lose their chromatin;
but at no time does the layer become broken. The parietal layers
at the time of the tetrad division are three to five in number, the
endothecium is thickened on its inner and lateral walls, and the
epidermis is undifferentiated. The thickening of the endothecium
walls takes places very late—simultaneously with the division of
the pollen grain nucleus—the cells for some time previous to this
being filled with starch.

Dehiscence is by means of two longitudinal slits, each of which
opens two pollen sacs of the anther. A deep crease runs between
each pair of pollen sacs upon the two sides of the anther, penetrating
to the point at which the two microsporangia lic nearest each other
(fig. 13). At this point is a group of small cells reaching from one
microsporangium to the other, the walls of which are thrown into
creases and folds, and fail to thicken in the further development of
the anther, as do the neighboring cells.

The pollen mother cells apparently lie in the synapsis stage for
several days. At their first division it is possible to count the chro-
mosomes, the reduced number being twelve and their form short
and blunt (fig. 8).

The tetrad division is simultaneous, there being no formation of
wall after the first division. After a short period of adherence in
tetrads the pollen grains round off and acquire the coats. The
mature pollen grain is marked with cight meridional grooves so as
to resemble a muskmelon. Beneath the grooves the intine is several
times thicker than between the grooves (jig. 11). While the pollen
grain is yet within the anther the nuclear division takes place which
gives rise to tube and generative nuclei (fig. 12). In this condition
the grains are shed, the stamens nearest the ovary opening first, and
the outer ones successively.

OVULE AND MEGASPORE.

The placental outgrowths which arise from the flat sides of the
Ovary, at the point of juncture of the edges of the carpellary leaves,
grow inward almost to the center of the ovary, and these I shall
designate as the “main placental outgrowths” (fig. 14). Each

II0 BOTANICAL GAZETTE [avoust

main placental outgrowth sends out two lateral outgrowths so as to
resemble in cross section a letter T, in which the arms have been
bent downward. Each pair of adjoining lateral outgrowths
closely appressed and directed backward toward the angles of the
ovary. In the lower part of the ovary the adjacent lateral out-
growths fuse, but do not extend to the bottom, and in the upper part
they do not reach the wall of the ovary as do the main placental —
outgrowths. Upon the edges of the lateral outgrowths and upon —
the surfaces lying next the main outgrowths are borne the ovules
(fig. 15). The ovules at the base and top of the ovary lie ea

the intermediate ones having intermediate positions according :
their place in the ovary.

The summits of the carpellary leaves broaden and coalesce, and
grow out in a direction radial to the axis of the flower, so that while
their basal parts form the capsule and the stalk of the style, the tips
form the umbrella of the style (fig. 3). The tip of each carpellary
leaf organizes a very definite growing-point (fig. 28), and the portion
between the tips nearly keeps pace in growth. Upon the ventral
surface of each tip, just before it completes its growth, is formed the
protuberance which bears the stigmatic surface. F

The appearance of the primordia of the ovules upon the placentae —
takes place from the point opposite the angle of the ovary wall,
where the adajcent lateral outgrowths meet, successively toward —
the angle formed by the lateral outgrowth and the main outgrowth
(fig. 19). In vertical direction the development proceeds from the —

epidermal cells and the accompanying anticlinal division of the
epidermal cells, as is commonly the case. When the ovule first —
protrudes from the placenta there is no suggestion of a sporogenous
cell. At this stage of development the winter rest intervenes. The
first suggestion of a sporogenous cell comes with the enlargement of
a single subepidermal cell, which is the megaspore mother cell (fig. 1)- :
In three cases out of many hundreds examined there were two mother —
cells lying side by side. There is no tapetal cell. The bending by
which the ovule becomes anatropous begins at once, and is quite

1906] SHREVE—SARRACENIA PURPUREA III

marked by the time of the appearance of the mother cell. Both
transverse and longitudinal sections (figs. 16 and 17) show a double
layer of cells at the sides of the mother cell, and median longitudinal
sections show approximately five rows of cells in the ovule, exclusive
of the epidermis.

The integument is single, its development beginning by periclinal

_ divisions of subepidermal cells upon the convex side of the bending -

ovule, and continuing as a ring which grows rapidly on the side
where it began first and slowly on the opposite side, which lies next
the raphe. The rapid growth of the ovule is accomplished largely
by the chalazal end. By the time of the first division of the mother
cell the bending of the ovule is completed, the integument has grown
so as nearly to close the micropyle, and the mother cell has increased
in size and encroached upon the nucellar tissue so as to lie next the
epidermal cells over the entire distal end (fig. 20).

The difference in the time of appearance of the ovules upon the
different parts of the placenta causes a difference in the degree to
which the integuments develop (fig. 19), and also a difference in
the maturation of the mother cell, and the germination of the mega-
spore in ovules in the different parts of the placenta, a difference
which long remains evident.

At the first division of the mother cell it was not found possible
to count the number of chromosomes. The division is followed by
the formation of a wall (fig. 20), and in about half the cases observed
both the daughter cells again divide to form the normal linear
tetrad of megaspores (jig. 23). In the remaining cases the micro-
pylar daughter cell fails to divide, resulting in a series of three mega-
spores (fig. 21); and much less frequently the micropylar daughter
cell divides by a wall parallel or nearly parallel to the long axis of
the nucellus (fig. 22). In any casc it is the chalazal megaspore which
functions, the micropylar ones being appressed to the layer of nucellus
and absorbed. The maturation of the megaspore is coincident
with the tetrad division of the microspore mother cells.

EMBRYO SAC.

Such has been the elongation of the ovule by the time the megaspore
matures that the nucellus is lengthened five or six times its diameter,

zi2 BOTANICAL GAZETTE

bata made up of slightly elongated cells five or six rows thick in
median section. The integument, about five cells thick, has n 7
grown well beyond the tip of the nucellus, and its lips have beco:
somewhat appressed to form the long micropyle. The cells in
innermost layer in the integument show active division in the dir
tion of the greatest length of the nucellus, and by their dense pm 0
plasm and large nuclei stand out aceeeiag ae as a definite laye
which I shall designate as the “columnar tissue.’
After the disappearance of the megaspore sister cells the defail

integument. The chalazal end is pointed, occupies at this time
median position in the nucellus, and is apparently active in
degeneration of the nucellar tissue, in accommodation to its 0

sion. The daughter nuclei take places at opposite ends of the
embryo sac (fig. 24), and quickly undergo the second (fig. 25) 4
third divisions in the normal manner.

The mature embryo sac is typical in every respect. It is elonga
to four or five times its width, the sides lie next the columnar ti
and the base continues to be pointed and median. The synergl
lie side by side and the egg protrudes a little way below them, n
the center of the sac. The cytoplasm of the synergidae is de
and stains heavily with the Flemming triple; that of the egg is greath
vacuolated. The antipodals lie well together in the conical bi
of the sac (jig. 26). The polar nuclei meet midway between
ends of the sac, and after their fusion the endosperm nucleus ¢
tinues to occupy this position (fig. 26). After the fusion of the po

the remaining basal portion of the nucellus. In this activit
antipodals do not take part. The base of the sac remains p
but from being median now comes to lie against the columnar |
at one side of the nucellus by means of the absorption of the nut
tissue which lay between its previous position and the colu
tissue. The further enlargement of the sac is accompanied
pushing downward of the base between the nucellus and co!

1906] SHREVE—SARRACENIA PURPUREA 113

_ tissue, and in some preparations the antipodals would seem to have
been pushed to one side (fig. 27). The columnar layer now shows
its maximum development, being made up of deep, much-flattened
_ cells with darkly staining cytoplasm. The function of these cells
is no doubt that of secreting and passing over to the sac sugars or
other elaborated foodstuffs.

POLLINATION AND POLLEN TUBES.

Pollination takes place, near Baltimore, during the first week in
May. In the mature style of Sarracenia at the time of pollination
the umbrella is a pale green color. Its internal structure is leaf-like
_ without a definite palisade, but with abundant intercellular spaces
4 and stomata numerous upon the upper surface and few upon the
4 lower. Long unbranched unicellular hairs cover the lower surface
_ so thickly as to form a tomentum in which considerable pollen is
caught at the time of shedding. There are also upon both sides of
the umbrella multicellular glands of spheroidal shape projecting
slightly above the level of the epidermis. Running from the five
stigmatic surfaces toward the center of the umbrella are heavy veins
~ which comprise both vascular and conducting tissue.

_ The union of the carpels in the formation of the stalk of the
style is such as to leave at its center a pentagonal cavity which in the
mature flower connects the interior of the capsule with the external
air. An cxamination of the veins of the umbrella two weeks before
pollination will show the conducting tissue as a cylindrical strand
about ten cells in diameter. The cells are much elongated, with
pointed ends, or many cells of this description have divided trans-

versely to two or four cells. The cytoplasm is dense, the nuclei are
large, elongated, often three times as wide as long, binucleolate, and
poor in chromatin. At the time of the passage of the pollen tubes
the conducting strand has become enlarged to more than twice its
_ previous diameter at the expense of the surrounding tissue, and the

cells have become still more elongated. The cytoplasm is much vacu-
-Olated, the nuclei are attenuate at the ends and devoid of nucleoli
(78s. 32, 33), and there are large intercellular spaces. The vascular
tissue of the veins lies beneath the conducting tissue and is continuous
‘ with the vascular tissue of the stylar stalk.

II4 BOTANICAL GAZETTE

‘Two weeks before pollination transverse sections of the stz
the style show five strands of heavy-walled cells running from th
angles of the central cavity half way to the periphery (jig. 34).
tissue which these cells represent in cross section is four to six
thick and runs the entire length of the stalk, being in the me
line of the carpels. About the time of pollination these i
cells are found to split into two layers, which separate in such a mé

(jig. 35). The surface layer of cells on the interior of the
becomes detached and undergoes partial degeneration. The
conducting canals thus formed are continuous with the condu .
tissue of the veins of the umbrella above, and open below midw
between the main placental outgrowths.

The stigmatic surface is richly provided with long, curt he:
walled outgrowths of epidermal cells (fig. 31), which serve to ¢
pollen and hold it. Pollen was found to be present in abund
on all stigmas examined. There is no definite sprouting- PS
the grains, but the tubes grow more commonly from the meridio
grooves. The pollen tubes grow between the cells of the stig

of the conducting tissue along the vein of the umbrella and do’
the stalk of the style (fig. 30).

The generative nucleus was not seen in any case to have div
before the sprouting of the pollen tube, and the earliest positio
which it was seen to have divided was in a tube which had n
reached the center of the umbrella. The tube nucleus is spheri
and precedes the generative nuclei. The latter are alike in form
elongated and curved or often bent twice in serpentine ma
The distance of the nuclei from the end of the tube is four t
times the diameter of the tube. The cytoplasm is dense in the
end and around the nuclei (fig. 36).

When the pollen tubes enter the cavity of the ovary i
five conducting tubes of the stalk, they are directly above the
juncture of the two adjacent lateral placental outgrowths.
course of the pollen tubes is at first a downward one bety
outgrowths, and later an outward one radial to the axis of

ae en

i oat i le ad

1906] SHREVE—SARRACENIA PURPUREA 115

_ (fig. 30). In this manner the edges of the placentae are reached

after a course in the ovary which, for the tubes growing to the lower-
most ovules, is as much as 6 to 8™™, and lies entirely outside the

_ tissue of the plant in an ovary the cavity of which has direct com-

_ munication with the external air. The epidermal cells of the placental

Wee

surfaces between which the pollen tubes pass are densely filled with

_ cytoplasm; beneath them lie three layers of flattened cells of similar
contents. Thin transverse walls are formed in the tubes near the
_ stigmatic surface (fig. 37), and far down in the ovary, near the
_ ovules, plugs are not infrequent in the tubes, being three to six times
_ the diameter of the tube in length.

The distance traversed by the pollen tubes which reach the lower-

~ most ovules in flowers of average size, is about 4°". Provision for

the nutrition of the tube during its growth and passage is perhaps
made in part by the photosynthetic activity of the umbrella. Pre-
vious to pollination the epidermal, subepidermal, and some deeper
cells of the umbrella are filled with densely-staining, finely granular
contents. In fresh material of the same age the contents of these

_ cells fail to react to tests for sugar made with Fehling’s solution, a-
_ naphthol and thymol, as well as to tests for starch. Similar contents
_ fill the epidermal cells of the stalk of the style. The ‘course of the

tubes as far as their entrance to the ovary is doubtless through a

_ Strong solution of sugars. Below the point of entrance to the ovary
_ the passage between the placental walls is probably through a film
_ of sugary solution held there by capillarity and supplied with mate-
als from the epidermal cells of the placental walls, which after
pollination are highly vacuolated, in marked contrast to their con-
dition before pollination.

FERTILIZATION.

The fusion of the male and female nuclei in fertilization is pre-

ceded by the division of the endosperm nucleus in nearly all the
embryo sacs. Fertilization takes place, then, in all ovules at nearly
_ the same time irrespective of a difference in the development of the
a endosperm due to the position of the ovule upon the placenta. As

to the length of time intervening between pollination and fertiliza-

_ tion Tam unable to give any exact data. A visit on May 24 to plants

116 BOTANICAL GAZETTE [AucusT

growing in the open found the anthers nearest the ovary to have
shed their pollen. Material collected at the same locality two days —
later was found to show fertilization. The time of pollination of —
the particular flowers gathered and fixed may have been as much —

as five days before gathering, but was probably not earlier.

The thin-walled slender pollen tubes may be found in abundance —
about the mouths of the micropyles, often forming considerable —

masses. The cells which line the micropyle are heavy-walled and
of such darkly-staining contents that it is difficult to observe the
pollen tube within the micropyle, and indeed the entrance of the
tip of the tube, with the nuclei, was not observed. The synergidae
become appressed to the wall of the sac. The end of the tube upon
entrance to the sac becomes expanded and pushes downward to
one side of the egg. The generative nuclei have lost the elongated
shape they were seen to have while passing down the style and have

become spherical. Fusion of the first generative nucleus shows 10 —

special peculiarities (fig. 38).
ENDOSPERM. .

The fusion of the polar nuclei is quickly followed by division.
The first wall in the endosperm is transverse to the length of the sac

and divides it into equal halves (fig. 39). The daughter nuclei —

divide in like manner (fig. 40), as do also the grandaughter nude),
giving rise to an endosperm of eight cells in linear series, in which
the walls are all transverse, although not uncommonly somewhat
oblique (fig. 41). Subsequent divisions are less regular, and by thé
time the fertilized egg has divided the endosperm contains approx

mately 150 cells, its base having used up the nucellus either com™ :

pletely or all but a half dozen cells (fig. 42). At this time the endo

sperm cells are highly vacuolated and the laying down of food has

not begun.

The relative rate of development of the endosperm in ovules upo? —

different parts of the same placenta is the same as was noted with

regard to the integuments. An ovule at the point of juncture of 4
the adjacent lateral placental outgrowths may have an eight-celled .

endosperm at the same time that the endosperm nucleus has not

yet divided in an ovule upon the edge of the placenta nearest the

main placental outgrowth.

Te

Shia

Peng etre ae Tee

é

1906] SHREVE—SARRACENIA PURPUREA i ee

EMBRYO.

The first division of the fertilized egg is in a direction parallel
with the length of the sac. The two-celled embryo (fig. 43), at first
oval, becomes gradually elongated, divisions following in the same
plane as the first, but not in a manner in which it has been possible
to discover any regularity. After the embryo has attained a length
of five to seven cells, there is a lateral division of the terminal cell
(7g. 44), the beginning of the embryo proper. The suspensor is

. usually curved, though not always to so great an extent as shown

in the figure. I have been unable by lack of material to observe
Stages in the development of the embryo immediately following the
transverse division of the terminal cell.

In material of June 25 the embryo proper is found to have reached
a size of approximately 250 cells, with ellipsoidal form (fig. 45).
Dermatogen and periblem are well-defined, but no procambial cells
have as yet appeared. The endosperm has by this time increased
greatly in diameter, encroaching upon the tissue of the integuments.
The endosperm cells have become well-stored with aleurone except
in the central portion of the micropylar end—the region destined
to be occupied by the full-sized embryo of the mature seed. In
embryos as large as that shown in fig. 45 the suspensor is surrounded
by endosperm cells in which aleurone has been laid down; the
embryo proper is surrounded by cells of highly vacuolated contents.

SEED AND SEEDLING.

Material gathered during the last week of July exhibits seeds
Which are practically mature. The embryo has grown to an elon-
gated ellipsoidal form, the cotyledons being about one-third the
length of the whole (fig. 46). Elongated procambium cells stretch
from the basal end of the embryo to the region of the stem growing-
point. Stomata are not formed in the embryo until the time of
germination. A few endosperm cells at the sides and cotyledonary
end of the embryo are free of aleurone, as they remain in the mature
seed.

The surface layer of cells of the integument forms the seed coat.
Its cells become irregular on their external surface and the walls
are greatly thickened, with conspicuous pores in the lateral and
basal walls, but none in the walls forming the surface of the seed

118 BOTANICAL GAZETTE [avoust

(jig. 47). The inner cells of the integument are all disorganized 7
by the growth of the endosperm and reduced to a layer of the remain- 4
ing walls of flattened cells. The raphe of the ovule develops into 4 —
wing upon one side of the seed, as seen in fig. 47. In the mature q
seed there is a coating of wax upon the surface which renders them —
unwettable, a condition in which they remain for several weeks —
after they have been placed in wet moss. 7 7

Provision for the shedding of the seed is made by a deep furrow
surrounding the raphe just at its junction with the placenta (jig. 48).
The dehiscence of the capsule is loculicidal and is provided for by —
a deep suture upon the external surface of the capsule wall ata
point where the wall is traversed by a heavy vascular bundle. Dehis- 4
cence takes place late in September or early in October, the seeds —
are scattered gradually during many weeks by chance shaking of 4
the scape by wind or animals. The old flower, with umbrella and a
sepals still persisting, is often found side by side with the bloom of 4
the following year. q

On germination the seed is elevated above the soil or moss by 4
growth of the hypocotyl, which is sharply bent and is the first part
of the seedling to protrude. The tips of the cotyledons remain for 4
some time in the seed, functioning as haustoria for the removal of the 4
stored food of the endosperm. The tips of the cotyledons are active q
in the removal of the endosperm both at their ends and along tell
sides (fig. 49). The cotyledons expand to liguliform leaves about
1°™ long (jig. 50), and persist until about the time of the formation
of the third epicotyledonary leaf. The cotyledons develop stomata a
_ during the process of germination and the epidermal and subepr
dermal layers of isodiametric cells bear chlorophyll.

DEVELOPMENT OF LEAVES.

The stem growing-point of Sarracenia is massive and acutely
dome-shaped in the seedling (fig. 57). There is a definite layer of
dermatogen and a common group of initials for periblem and plerome
The first epicotyledonary leaf arises opposite the interval betwee?
‘the cotyledons. It is finger-shaped with a somewhat broadened
base. On reaching a length about twice its diameter there beg!?>
a rapid lateral outgrowth of the tissue of an 0-shaped area on the

SS Sei 3 = i iat

1906] SHREVE—SARRACENIA PURPUREA I19g

side of the leaf rudiment which faces the growing-point, giving rise
to a pit which is destined to become the cavity of the pitchered leaf
(jig. 52). The basal part of the 0-shaped outgrowth now begins
to grow upward, in which it is accompanied at the same rate by the
upper portion of the 0, which at the same time carries forward the
apical growth of the leaf (fig. 53). The cavity of the pitcher thus
grows in depth by the upward growth of the tissue by which it is
surrounded, The bottom of the cavity is subsequently elevated
to some extent by the further growth of the tissue beneath it, but
there is no sinking of the bottom of the cavity, considered as a possi-
bility by ZrppeRER.? The entire carly development of the leaf
resembles closely that which has been described for Darlingtonia
californica by GOEBEL.3

The first epicotyledonary leaf reaches its maximum size at a
length of about 2.5°™, and is slender in form, the cavity reaching
well down toward its base, and the wing being but slightly developed.
At the summit it is hooded in such a manner as to resemble the
mature leaf of S. variolaris. The walls of the pitchers of the seedling
are six to eight cells in thickness, with open mesophyll, chlorophyll in
all the cells, and stomata over the entire external epidermis. There
are two principal strands of vascular tissue, one in the base of the
wing and one on the opposite side of the pitcher, with smaller anas-
tomosing strands between these. In the throat, of the pitcher all
the epidermal cells are produced into long projecting points; lower
in the pitcher occasional epidermal cells, smaller than the others,
give rise to long heavy-walled hairs, while in the bottom of the
pitcher the epidermal and first layer of subepidermal cells are small
and heavy-walled.

While each leaf of the young plant is passing through its period
of most active growth, the internode between it and the next lower
leaf is also elongating rapidly. A young leaf appears for this reason
to arise from the petiole of the leaf below it (fig. 5z). The relative
elongation of the internodes is far greater in the seedling than in the
adult plant.

The growth of a single plant from seedling to adult was not fol-

Beitrag zur Kenntniss der Sarraceniacees: Inaug. Diss. Erlangen. 1885.

3 Pflanzenbiologische Schilderungen II. 5:73-02- pls. 19-29. 1893-

120 BOTANICAL GAZETTE [avoust

lowed, but evidence points to the time requisite for the seedling to”
reach blooming age as being five or six years. Seeds of the crop ol
1go1, which in October of that year were placed in sphagnum in ¢
loosely covered glass vessel, germinated in July 1902, and now, after —
33 months, have no pitchers measuring over 2™™ in diameter. The —

kept would make it inadvisable, however, to draw from them any
general conclusions as to the rate of growth in the scedlings under
natural conditions. The great number of intermediate stages in
growth between the seedling and adult which may be observed in a ~
single locality at any one season would also argue for the slowness —
of the plant in reaching adult size.

The stem growing-point of the adult plant is more broadly dome
shaped than that of the seedling, but is identical with it in the mode
of origin of the dermatogen, periblem, and plerome. The earliest
primordium of the leaf is likewise more massive than in the seedling,
but essentially similar. Its form is conical, with a broadly semi-
circular base embracing the growing-point. Near the summit, upon
the side toward the growing point, is developed the narrow pit which
is destined to form the cavity of the pitcher, its origin being due
wholly to a difference in the rate of growth of the tissue at the bottom
of the pit and that forming its sides (fig. 54). BArtLon‘ in a brie
note on the development of a Sarracenia (species not mentioned)
has described this early stage and called attention to its similarity
to an early stage in the development of peltate leaves, averring that
“La membrane qui tapisse intérieurement l’urne n’est autre chose
que l’épiderme supérieur de la feuille.”” This may be an entirely ‘
superficial analogy, or it may be a hint as to the ultimate origin
such a markedly modified leaf. Gorset (/. c.) has figured the early
leaf primordium of S. Drummondii, which is essentially like that
S. purpurea.

With the continued growth of the leaf rudiment the pit becon
deeper, and its mouth becomes vertically elongated, although remain-
ing very narrow. At stages somewhat earlier than that shown ™
fig. 55, the sides of the mouth of the pit have come together, clos-
ing it completely. Fig. 55 represents a leaf primordium in which

4 (Note on the development of leaf of Sarracenia) Adansonia 9: 380. 1879-

1906] SHREVE—SARRACENIA PURPUREA 121

the wing is just beginning to appear. Figs. 56-61 represent cross
sections of the primordium at this age in the places indicated in
fig. 55..

In older leaves, such as are represented in fig. 62, the base of the
leaf primordium is stoutly crescentic in cross section. Through the
groove at the inner side of the leaf base the next younger leaf appears
(jigs. 55 and 62). The groove becomes narrower and more shallow
as we pass up the leaf and ends just short of the bottom of the cavity
of the pitcher (fig. 62). Above the end of the groove there is a short
portion of the young leaf which is circular in cross section, above
which in turn the narrow flattened outgrowth of the wing has become
More conspicuous. The wing rudiment ends rather abruptly at a
point where retardation of growth in diameter indicates the line of
demarcation between the pitcher and cover. The cavity of the pitcher
at this stage reaches as far as the upper end of the circular portion
of the base.

There have been many suggestions as to the homology of the parts
of the pitchered leaf of Sarracenia. A view held by many is that
the pitchered portion of the leaf is derived from the primordium of
the petiole and the cover from the primordium of the lamina. Gokr-
BEL (/. c.) points out that since there can be no distinction in the very
young leaf of primordia of petiole and lamina there can be no line
drawn as to what portions of the pitchered leaf “represent” these
Structures.

The anatomy of the mature leaf was first worked out by VoGL;°
it has more recently been reviewed by GoEBEL (/. c.), and minor
contributions have been made by ScHIMPER® (1882) and ZIPPERER
(/. c.). The first leaf rudiments unfolded in the spring are aborted
(fg. 62), consisting of the sheathing base surmounted by the minute
retarded primordium of pitcher and cover. These are usually
three in number, and may occur in plants which do not bloom, as
well as in those which do. In the latter case the aborted leaves are
those just above the one to which-the flower appears to be axillary.

5 Die Blatter der Sarracenia purpurea. Sitzungsb. Wiener Akad. Wiss. Math.-
Naturw. 50: 281-301. pls. 2. 1864.

°Notizen iiber insectfressende Pflanzen. Bot. Zeit. 40:225-234, 241-248.
Pl. 4 (figs. I~3). 1882.

122 BOTANICAL GAZETTE [Aucusr

The axillary buds of Sarracenia are commonly very small and
consist of growing-point and the primordium of a single leaf, com-
pletely covered and protected by the sheathing leaf base. An
occasional axillary bud develops, the first two leaves being opposite
and on the opposite sides of a line connecting the growing-point
of the bud with the center of the shoot. There is thus brought
about a branching of the rhizome, which by frequent repetition gives
rise to large clusters of individuals.

The anatomy of the rhizome of S. purpurea has been described
by ZIPPERER in sufficient detail, since it presents no unusual fatures.
He has also given a correct account of the growing-point of the root
and the development of the vascular tissue of the root: the growing-
point being of the type in which the cap and three tissue layers are
all derived from a common group of initials; the early order of
vascular bundles being triarch.

Root hairs are few upon the roots of plants growing in a saturated
substratum in the open, but are abundant in seedlings grown in
highly saturated sphagnum, and in adult plants in the open which
are growing in a substratum merely moist. Mycorhiza has not been
observed in S. purpurea in the vicinity of Baltimore, although fungal
threads have been found covering the root of seedlings grown under
the conditions previously mentioned and penetrating the epidermis.
MacDoveat’ (1899) has described penetration of the epidermis
by hyphae in adult plants without committing himself as to their
mycorhizal nature.

SUMMARY.

1. The flowers of Sarracenia purpurea are axillary, perfect,
hypogynous, and radially symmetrical. The stamens are seventy —
to eighty in number and arise in ten groups. There are four micro- —
sporangia. There is a double layer of binucleate tapetal cells,
derived from the primary archesporium. There are three to five
parietal layers. The tetrad division is simultaneous; the micro-
spore nucleus divides before the dehiscence of the anthers. The
reduced number of chromosomes is twelve.

2. In the ovule there is a single archesporial cell, which is the
megaspore mother cell. There is no tapetal cell. The ovule is

7 Symbiotic saprophytism. Annals of Botany 13:1-47. 1899.

1906] SHREVE—SARRACENIA PURPUREA . 123

anatropous and there is a single integument. The megaspore mother
cell divides to a linear series of four megaspores, or after the first
division the micropylar nucleus may fail to divide or may Ve by
a wall longitudinal to the ovule.

3. The chalazal megaspore is functional, and develops a typical
eight-celled embryo sac. The polar nuclei fuse and the endosperm
may become two to eight-celled before the complete fusion of male
and female nuclei in fertilization.

4. The pollen tube grows through a definite conducting tissuc
in the upper expanded portion of the style, through schizogenic
canals in the stalk of the style and between the placental outgrowths
in the ovary. The generative nucleus divides before the tube has
passed into the stalk of the ovary. Fertilization presents no pecul-
iarities.

5. The embryo is elongated and straight, with cotyledons. The
storage tissue is endosperm filled with aleurone. The seed coat is
the external layer of the integument. The cotyledons function as
haustoria in germination and survive as chlorophyl-bearing leaves.

6. The first epicotyledonary leaf is pitchered and arises from a finger-
like primordium in which a cavity is developed by unequal aati

THE Woman’s COLLEGE OF BALTIMORE,

Baltimore, Md.

EXPLANATION OF PLATES III-V.

Abbreviations used: ant, antipodal; arsp, archesporium; br, bract; cav,
cavity; col t, columnar tissue; con c, conducting canal; con s, conducting strand;
con t, conducting tissue; cot, cotyledons; cov, cover; cp, carpel; der, dermatogen;
d s, dehiscing slit; e, egg; em, embryo; en n, endosperm nucleus; ¢ s, embryo
BAG, GER, endosperm; f n, female nucleus; g , generative nucleus; im, integu-
ment; int i, integument initials; J,.leaf; 1 p 0, lateral placental outgrowth; meg

megaspore mother cell; meg sc, megaspore sister cell; mic mc, microspore
testes cell; micsp, ha, ascent mn, male nucleus; m p 0, main placental
outgrowth; uc, nucellus; ovary; par c, parietal cells; pet, petals; pn,
polar nuclei; pi, initials of :sscstibee and plerome; pro c, procambium cells;
Sc, seed coat; sep, sepal; st, stamen; stg s, stigmatic surface; stk, stalk of
Style; sus, suspensor; syn, synergid; tap c, tapetal cells; im, tube nucleus; um,
umbrella of the style; w, wing.

All figures are camera drawings fom microtome sections except jigs. 29, 30,
5°; 55, and 62, which are from free-hand drawings.

124 BOTANICAL GAZETTE [AUGUST —

PLATE III,

Fic. 1. Vertical section of young flower bud. x 30.

Fic. 2. Transverse section of young flower bud of same age asin fig. 1; dotted —
outline represents position of carpel tips in higher sections. X 30.

1G. 3. Vertical section of older flower bud. X 30.

Fic. 4. Transverse section of young stamen. X 232.

Fic. 5. Transverse section of single microsporangium of older stamen. X232.

Fic. 6, Tranverse section of portion of microsporangium and wall in micro-
ae ae cell stage. > 400.

G. 7. Transverse section of portion of microsporangium and wall with

Paes mother cells in synapsis. 232.

Fic. 8. Transverse section of mircosporangium and portion of wall; pollen
mother cells in mitosis. 400.

Fic. 9. Pollen mother cells in metaphase of first mitosis. > 400.

Fic. 10. Tetrads of ot xX 400

Fic. 11. Pollen . 400.

Fic. 12. Pollen eas after division of nucleus. x 400.

Fic. 13. Transverse section of mature seo X 20.

Fic. 14. Transverse section of young ovary.

Fic. 15. Transverse section through middle fs ae mature ovary. %7-

7. Trans

Fic. 18. Longitudinal section of ovule with megaspore mother cell and integ-
ument. 232. 5

Fic. 19. Transverse section of single lateral placental outgrowth, showing
difference in rate of development of integument on different parts of the placenta;
somewhat diagrammatic. > 40.

PLATE IV.

Fic. 20. First maturation division of megaspore mother cell. > 400

Fic Linear series of three megaspores, arising by failure of nical
daughter cell to divide. x 400.

22. Tetrad of megaspores in which the micropylar daughter cell has

Fic
divided longitudinally. 400

Fic. 23. Longitudinal section of ovule, with tetrad of eticuede chalazal
one enlarging and encroaching on single layer of nucellus. x1

Fic. 24. Longitudinal section of portion of ovule showing le embry?
sac, nucellus, and columnar tissue. X 232.

Fic. 25. Longitudinal section of portion of ovule showing four-celled embry°
SAC. XxX 232.

Fic. 26. Longitudinal section of portion of ovule showing fully developed
embryo sac.

FIG. 27. Lomsindian section of portion of ovule — embryo sac after
fusion of polar nuclei; antipodals pushed to one side. 232

BOTANICAL GAZETTE, XLII

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BOTANICAL GAZETTE, XLII

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1906] SHREVE—SARRACENIA PURPUREA 125

Fic. 28. Growing point of tip of carpel in umbrella, horizontal section. > 4o.

Fie. ste Stylar umbrella viewed from above; in outline. x 4.

Fic. 30. Ovary and style to show the course of pollen tube indicated by
dotted om somewhat diagrammatic. x2

Fic. 31. Longitudinal section of stigma surface with sprouting pollen
grains, X 120.

Fic. 32. Longitudinal section of conducting strand in umbrella of style
eo conducting and vascular tissue. X 40.

33- Transverse section of upper surface of umbrella of style showing
ncaa. and vascular tissue and glandular epidermis. X 120.
1G. 34. Transverse section of stalk of style before pollination. X 20.

Fic. 35. Transverse section of stalk of style at time of pollination. X20.

Fic. 36. Tip of pollen tube from conducting tissue of umbrella; optical
section. X 400.

Fic. 37. Cross wall in tube near stigmatic surface. X 400.

PLATE V.

Fic. 38. Longitudinal section of upper end of embryo sac showing fusion
of male and female nuclei. 400.

Fic. 39. Longitudinal section of embryo sac showing two-celled endosperm,
columnar tissue, and remains of nucellus. x 120.

Fic. 40. Longitudinal section of embryo sac showing four-celled endosperm.
X 120,

Fic. 41. Longitudinal section of portion of ovule showing eight-celled endo-
ages Sere integument. X 40.

G. 42. Longitudinal section of seed through the wing showing multicel-
lular pa oe and two-celled embryo. X20.

Fic. 43. Two-celled embryo. X 232.

Fic. 44. Young embryo with suspensor. % 400.

Fic. 45. Older embryo with suspensor. 232.

Fic. 46. Longitudinal section of embryo from mature’ seed. X 120

Fic. 47. Tranverse section of men seed cutting the embryo through the
cotyledons; detail partially filled in. X4o.

Fic. 48. Longitudinal section aie the hilum of nearly mature seed.

Fic. 49. Longitudinal section of germinating seed, with cotyledons; hee
Coat has been removed; portion beyond the dotted line is that from which
aleurone has not yet been removed. X20

Fic. 50. Seedling with cotyledons a three aacoasmnoede pate p eee

Fic. 51. Vertical section through growing-point of seedling.

FIG. 52. Median vertical section through primordium of oa pare
donary = X 232.

Fic. 53. Median vertical section through portion of primordium of first epi-
cotyledonary leaf in later stage of development. X 232.

126 BOTANICAL GAZETTE [AUGUST

Fic. 54. Vertical section through growing point and young leaves in adult
plant. X20.

Fic. 55. Surface view of primordium of leaf seen from the side, next younger
leaf also showing; dotted outline marks cavity of leaf. 3.

Fic. 56. Transverse section of leaf in jig. 55 at 56. X20.

Fic. 57. Transverse section of leaf in fig. 55 at 57. X20:

Fic. 58. Transverse section of leaf in fig. 55 at 58. X20. :

Fic. 59. Transverse section of leaf in fig. 55 at 59. X20.

Fic. 60. Transverse section of leaf in fig. 55 at 60. X20. |

Fic. 61. Transverse section of leaf in fig. 55 at Or.

Fic. 62. Later stages of young leaves; eS shown pees outline. X1

ON THE IMPORTANCE OF PHYSIOLOGICALLY
BALANCED SOLUTIONS FOR PLANTS.’
I. MARINE PLANTS.

W.cJ. V.OSteR nour.

RINGER demonstrated that animal tissues live longer in a solution
of NaCl to which a small amount of KCl and CaCl, is added than
in a solution of NaCl alone. Various explanations of this fact were
given by different investigators, all of whom, however, agreed upon
the essential point that KCl and CaCl, are essential for the mainte-
nance of life.

HowELt assumed that CaCl, is the stimulus for the heart beat,
while NaC] is an indifferent substance, necessary only for the mainte-
nance of osmotic pressure. Similarly RrNGER concluded that Ca is
the stimulus for the systole, while K is necessary for the diastole of
the heart beat.

HERgstT made experiments on the influence of the composition of
the sea water on sea urchin eggs, eliminating in each successive
experiment a different constituent of the sea water. He found that
the eggs would not develop in any solution which did not contain
all the salts of the sea water. From this he concluded that each of
the salts found in sea water is necessary for the development of the
egg. Loe called this view in question as the result of his experiments
on Fundulus. He found that this marine fish cannot live in a pure
NaCl solution of the same osmotic pressure as the sea water, but that
it can live indefinitely in a mixture of NaCl, KCl, and CaCl,, in the
same proportions in which these salts are contained in sea water.
The fish can also live indefinitely in distilled water. This proves
that it does not need any of the three salts mentioned for the mainte-
nance of its life, and that the Ca and K are only required to overcome
the poisonous effects which would be produced by the NaCl if it
alone were present in the solution (at the above mentioned concen-
tration).

I wish here to express my sincere thanks to Professor Logs, who kindly placed
the facilities of his laboratory at my disposal and assisted me in every way during
these investigations. ‘

ae {Botanical Gazette, vol. 42

128 BOTANICAL GAZETTE [AUGUST

It is noteworthy that the Ca and K, which are added to inhibit —
the toxic effect of NaCl, are themselves poisonous at the concentra- —
tion at which they are here employed. F

These antagonistic effects of Ca and K toward a pure NaCl solu- —
tion were illustrated still more strikingly in experiments on the egg 4
of Fundulus. The newly fertilized eggs of this fish develop equally 4
well in sea water and in distilled water, but die in a pure m/2 NaCl 4
solution without forming an embryo. If, however, a small but defi- 7
nite amount of a salt with a bivalent kation, even of such poisonous —
salts as BaCl,, ZnSO,, and Pb(CH,-COO),, is added, the eggs will 4
produce embryos. From these and similar observations LoEB Was
led to formulate his conception of the necessity of physiologically 4
balanced salt solutions, in which are inhibited or counteracted the —
toxic effects which each constituent would have if it alone were a
present in the solution. a

The blood, the sea water, and to a large extent RINGER’S solution, —
are such physiologically balanced salt solutions. The observations
of HERsst, as well as those of RINGER, are easily explained on this —
basis. The fact that the elimination of any one constituent from —
the sea water makes the solution unfit to sustain life does not prove
that the eliminated substance is needed by the animal for any purpose —
other than to counteract the poisonous action of some other constlt
uent of the solution. =

Botanists have not thus far made use of these conclusions, for the —
obvious reason that facts similar to those mentioned above have ne
been observed in plants. I have recently made a number of expel
ments which show that there exist in plants phenomena similar to
those observed by Lors on Fundulus and other marine animals.

The species of marine plants chosen for investigation may be
divided into two groups: -

Group 1 comprises plants which can live a long time in distilled
water. It includes the following: BLUE-GREEN ALGAE, Lyngby
aestuarii; GREEN ALGAE, Enteromorpha Hopkirkii; FLOWERING
PLANTS, Ruppia maritima. Gg

Group 2 is composed of plants which quickly die in distilled 4
water. It includes the following: GREEN ALGAE, Enteromorph@ 4
intestinalis; BRowN ALGAE, Ectocarpus confervoides; RED ALGAEs 4

1906] OSTERHOUT—BALANCED SOLUTIONS 129

Ptilota filicina, Pterosiphonia bipinnata, Iridaea laminarioides,
Sarcophyllis pygmea, Nitophyllum multilobum, Porphyra naiadum,
Porphyra perforata, Gelidium sp., Gymnogongrus linearis, Gigartina
mammillosa.?

If plants of either group be placed in a solution of pure sodium
chlorid (isotonic with sea water), they die in a short time. This
might be attributed to the lack of certain salts which are necessary
for their metabolism, rather than to the toxicity of the sodium chlorid.
In the case of the plants of Group 1 there can be no doubt on this
point, for these plants live a long time in distilled water. If we add
pure sodium chlorid to the distilled water it kills them in a very
short time. An inspection of the tables will show that. these plants
in their behavior toward sodium chlorid and other salts, closely
agree with those of Group 2, which can live but a short time in dis-
tilled water. Sodium chlorid is certainly toxic to the first group,
and there can be little doubt that it is so to the second group as
well.

The plants of the first group were found in a ditch in a salt marsh
through which the tide ebbs and flows; there is always a foot or
So of water even at low tide. The salt content of the water fluctuates
around a mean of approximately 2.3 per cent.

The plants of the second group were collected at the entrance to
San Francisco Bay, where the salt content of the water fluctuates
about a mean which is probably not far from 2.7 per cent. The
only exceptions are Enteromorpha intestinalis and Ectocarpus con-
jervoides, which came from wharves in the bay, where the mean salt
content is about 2.3 per cent.

All the plants used in the experiments were transferred from the
sea water directly to distilled water. After rinsing in this they were
Placed in glass dishes, each containing 2c0°° of the solution to be
tested. The dishes were then covered with glass plates to exclude
dust and check evaporation. Only a small amount of material was
Placed in each dish. The temperature during the experiments did
not vary far from 18° C.

Artificial sea water was prepared} according to VAN ’t Horr’s

? The determinations were kindly made by Professor SETCHELL.

’ The water used was distilled in glass only and the first part of the distillate
rejected. The purity of each salt was carefully tested before using.

130 BOTANICAL GAZETTE [Avcust

formula‘ as follows: 1ooo°* NaCl, 3m/8; 78°° MgCl,, 3m/8; 38°
MgsSO,, 3m/8; 22°° KCl, 3m/8; 10°° CaCl,, 3m/8.° .

This closely approximates the bay water. The plants thrive
almost as well in it as in sea water, especially when a very little |
NaHCO, or KHCO, is added to produce a neutral or faintly alka-
line reaction.

A series of solutions was tried, beginning with pure NaCl 3m/8
and adding to it in turn MgCl,, KCl, and CaCl,, either singly or in
combination, in the proportions given above. These salts were also —
used in pure solutions of the same concentration at which they exist
in the artificial sea water described above. :

It should be said that little difficulty was experienced in deter- —
mining the death point with sufficient precision. The color reactions 4
and the microscopic appearance of the cells allowed this to be done :
with sufficient accuracy, so that the results were not in doubt on this
account. ,

The results of the experiments are set forth in the tables. The
figures represent the average of four parallel series carried on simul-
taneously. A control series was also carried on in which each solu-
tion was made faintly alkaline by the addition of NaHCO,, KHCO,,
or Ca(OH),. This had a beneficial effect during the first ime or
three days of the experiment, but the final results were practically
the same as in the other series.

From a consideration of the results for Group 1 we may draw
the following conclusions.

1. The plants die much sooner in a pure sodium chlorid solutio
(isotonic with sea water) than in distilled water. The poisonous
effect of the NaCl largely disappears if we add a little CaCl, (10°
CaCl, 3m/8 to tooo®* NaCl 3m/8); in this mixture the plants jive
nearly as long is in distilled water. Addition of KCI to this m&®
ture enables them to live longer than in distilled water. F urther
addition of MgCl, and MgSO, enables them to live practically *
long as in sea water. 4

4 Van’t Horr, J. H., Physical chemistry in the service of the sciences I10f- Univ. ja |
of Chicago Press, 1903.

s This corresponds approximately to the proportion of Ca in the sea wate? of
the bay.

1906] OSTERHOUT—BALANCED SOLUTIONS 131

TABLE I.

DURATION OF LIFE IN Days.

GrouPpr . Group 2
CULTURE SOLUTION. ‘
Lyngbya | EBtero-| Ruppia | Prilota | Thonn | laminar
aestuarll | Hopkirkii | Meme fuicina | bipinnata | ioides
Sea aii om 2.9%) > 95 150+ 150+ II 24h 24
at ap se
© NaCl ee,
m8 g l ac :
ae MgSO, " go 150+ | 150+ | 10} 244 23
goo"! KG ie
TO: Cate: a
Distilled water......... 30 30 80 I 3 2b
‘hap Wael guia ees 32+ 36 85 24 9} 10
NaCl 3m/8 22 15 23 1} 3k 4
1000 cc NaCl zs 6<- 2 6
OG ape ee ; ; ;
tooo “ NaCl a“
4 ep eS fe 35 32 88 34 10 9
To: 5 CaCl. es
1000 NaCl a 6
MgCl, 6 29 23 45 2 6-
10: - Cats bie
tooo NaCl big
“* MgCl, i 25 133 30 2 4 4
Cl “ce
tooo “* NaCl bi 4 5
a EY > 23 134 23 I
1000 * NaCl : 2 I 2 2
78 “ MgCl, “ce 228 134 5 4
1000 * Dist. H,O 6 I I 2 24
7 Mgtts ef ois | Oh as
1000 “ Dist. H,O © > 1 2 2
38 “ MgSO, {} 7h | 13 .
1000 “ Dist. H,O 6 I 15 3
223 KC} ae ; igs 134 5 5
1000 “ Dist. HO 2 2
10 “ CaCl, nag et t 26+ 123 58 4 5

132 BOTANICAL GAZETTE [AUGUST

TABLE II.
DurRaATION OF LiFE In Days. GROUP 2.
3 Fe | 3 | :
42) |= | 65 = le
s2| 88|22|22|.8|22|- | 22! ag
CULTURE SOLUTION. Boi es | fe | Fs] es] 5S | 5 | 25 a g
A jeje [2 |e. |e |O |o 49
| airy pees peau mene
Sea water (total salt 2.7%)... .. 240 | 25 rr | 44 | 6 | 21 33+. 11.
Artificial sea water: |
I ¢ NaCl 3m/8 |
we Mae
38 “ MgSO agate artnet 220 | 20 | 74 | 44 | 6 |20 |33+]10 | 98
ae RCI - |
0° (CaCl es |
Distilled water. 4.) 23. aes ales =) 34) 8 | 241-24 | 38 | 16 | 23 | 33
Wap Wale re oS ee nie) 24 | 32| 33 | 23] 441 53 | 42 | 3t
Natt 40/8... MP kt ET eR 5 fs | tts
rooo ¢¢ NaCl 4 6
a2. KCl ener ee Os) & + 64) 44) § [144 133+} 9
1o “ CaCl, “c
¥o00'"* Dist: HO : |
22 “ KCl a (a4 ee rs 4% 4 1g 44 3 3 4 | 3

2. The pure solution of each of the salts added to inhibit the
poisonous effects of NaCl is itself poisonous at the concentration
at which it exists after its addition, since the plants die in such a solu-
tion much sooner than in distilled water.6 A mixture of solutions
which are individually poisonous produces a medium in which the
plants live indefinitely.

That the plants die so quickly in solutions containing a single salt
might be attributed to the fact that the osmotic pressure of some
of these solutions is much lower than that of sea water. This suP-.
position is disproved by the fact that in general the plants live longe
in tap water than in any solution containing but a single salt, although
the tap water has a lower osmotic pressure than that of any solu-
tion used in the experiments. (The plants of Group 1 live longet
in distilled water also. The tap water is to be regarded as a phy si:

6 This statement does not apply in all cases to CaCl,, which is the least toxic of
the salts employed and for some forms quite harmless in dilute solutions.

1906] OSTERHOUT—BALANCED SOLUTIONS — 133

ologically balanced solution; this will be more fully discussed in
the second portion of the paper.)

3- The poisonous effect of NaCl is inhibited little or not at all
by KCl or MgCl, added singly.

4. The combination NaCl+KCl+CaCl, is superior to NaCl+
MgCl,+CaCl,, but the latter is better than NaCl+ MgCl, +KCl.

5- These effects must be due to the metal ions, since the anion
is in nearly all cases the same.

The plants of Group 2 agree with those of Group 1 except in their
behavior toward distilled water.

Essentially similar results were obtained from the study of fresh
water algae and other plants, the details of which will be given in
the second part of this paper.

These results agree in striking fashion with those obtained from
the study of marine? and freshwater animals®.

The combination NaCl+KC1+CaCl, (in the same proportions
as in sea water) seems to be quite generally beneficial for —
and plants.

We may in conclusion briefly consider the effects of concentrated
solutions. A series of experiments were made on LEnteromorpha
Hopkirkii in which the plants were placed in dishes with a very little
sea water. This quickly evaporated, so that the plants became
covered with salt crystals in 24 to 48 hours. In this condition some
of them remained alive for about 1 50 days. This means that Entero-
morpha plants which remain alive only 15 days in 3m/8 NaCl solu-
tion can live rs0 days in an NaCl solution of 10 to 12 times higher
concentration, provided the other salts of the sea water are present
in the solution (at corresponding concentration) to inhibit the toxic
effect of NaCl. Experiments on Lyngbya, Ptilota, and Pterosiphonia
Save essentially the same results.

In view of these results, and others of a similar character shortly
to be published, it appears certain that physiologically balanced salt
solutions have the same fundamental importance for plants as for
animals,

7 Los, Pfliiger’s Archiv 107:252. 1905, and the literature there cited.

8 Ostwatp, a Archiv 106:568. 1905. Univ. of California Publications,
P pias 2:163. 1905.

134 BOTANICAL GAZETTE [AUGUST

RESULTS.

1. Each of the salts of the sea water is poisonous where it alone
is present in solution.

2. In a mixture of these salts (in the proper proportions) the
toxic effects are mutually counteracted. The mixture so formed is
a physiologically balanced solution.

3- Such physiologically balanced solutions have the same funda-
mental importance for plants as for animals.

THE UNIVERSITY OF CALIFORNIA,
Berkeley.

eae Sy Sea ee

THE APPRESSORIA OF THE ANTHRACNOSES.
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY.
LXXXIV.

HEINRICH HASSELBRING.
(WITH SEVEN FIGURES)

In describing a number of new plant diseases in 1883 FRANK'
gave an account of peculiar spore-like organs produced by the germ
tubes of spores of the bean anthracnose. He showed further that
these organs acted as holdfasts, by means of which the fungus
was firmly attached to its host during the early phase of develop-
ment. In the same paper he described analogous organs of Fusi-
cladium Tremulae and Polystigma rubrum, Almost simultaneously
Fiscu? described the holdfasts of Polystigma, but he did not at all
recognize their true significance. He regarded them as ‘‘secondary
spores”? which served in the distribution of the fungus, since the
ascospores are embedded in slime when ejected, and are therefore
not suited for dissemination by the wind. FRanx first recognized
he true nature of these bodies, and gave to all organs of this
class the name appressoria or adhesion organs. Later MEYER*
again described and figured the adhesion organs of Polystigma,
but added no new observations. In 1886 Dre Bary‘ first showed
that the complex adhesion organs of Sclerotinia were produced as
the result of a mechanical stimulus, but BtscENS made the most
complete study from a physiological standpoint. He showed that
the germ tubes of many parasitic fungi produce adhesion organs of

* FRANK, B., Ueber einige neue und weniger bekannte Pflanzenkrankheiten.
Ber. Deutsch, Bot. Gesells. 1:29-34, 58-63. 1883; Landw. Jahrb. 12:511-530-
pls. 3. 1883.

ue Fiscu, C.. Beitrage zur Entwickelungsgeschichte einiger Ascomyceten. Bot.
Zeit. 40:851-870. pls. 2. 1882.

_ °Mever, B., Untersuchungen iiber die Entwickelung einiger parasitischer
Pilze bei Saprophytischer Ernahrung. Landw. Jarhb. 17:915-945. pls. 4. 1

_ *De Bary, A., Ueber einige Sclerotinien und Sclerotinien-krankheiten. Bot.
Zeit. 44:377 et seq. 1886.

* BUscEn, M., Ueber einige Eigenschaften der Keimlinge parasitischer Pilze.
Bot. Zeit. 51:53. 1893.

5]

13 [Botanical Gazette, vol. 42

136 BOTANICAL GAZETTE © [AUGUST

various forms, and that their formation is due to a mechanical stimu-
lus resulting from contact of the germ tube with some solid body.

These accounts seem to have escaped entirely the notice of Amer-

ican writers on the bitter rot, as is indicated by the many speculations
and by the curious interpretations of the characteristic adhesion
organs of the bitter-rot fungus and of other anthracnoses. The
first economic account of the bitter rot appears in the Report of the
chief of the Section of Vegetable Pathology for 1887.° Here the
formation and germination of the appressoria are described. They
are regarded as secondary spores, but no particular function is

attributed to them. Excellent figures are also given on plate 3 of

the Report of 18907. In 1891 Miss E. A. Sourawortu® published
the most complete account of the fungus up to that time. Regarding
the ‘“‘secondary spores” Miss SouTHWoRTH says: ‘‘ What the con-
ditions were that decided their appearance could not be determined.
They were produced both in nutritive media and water, but seemed
to be especially numerous where the ends of the hyphae came in
contact with some hard substance like the cover-glass, and in two
cases the addition of an extra drop of nutritive medium had the effect
of stopping their formation.” As to their function nothing is said,
except that they are regarded as resting spores. (See mole, P. 142.)
In 1892 HALSTED published a short account of the secondary spores of
anthracnoses.° He extends the list of anthracnoses which produce
these organs to twenty-five species, including members of both
Gloeosporium and Colletotrichum. Axtwoop'? describes the Pro
duction of “resting spores” by the bitter-rot fungus, but from his
- figures and description it is impossible to determine whether he had
before him the bodies in question. Other writers have followed
these investigators in their interpretation of the peculiar adhesion

6 ScrrBNER, F. Lamson, Bitter rot of apples. Rep. Sect. Vegt. Path. U- S. Dept-
Agr. 1887: 348-350.
GatLoway, B. T., Ripe rot of grapes and apples. Idem. 1890:408

8 SourHwortH, E. A., Ripe rot of grapes and apples. Journ. Myc- 6: 164-
173. pl. I. 1891.

o HatsteD, B. D., The secondary spores in anthracnoses. N. J.- Agr. Exp-
Sta. Rep. 1892: 303.

ro ALwoop, W. B., Ripe or bitter rot of apples. Agr. Exp. Sta. Va. Bull. 49-
1894.

1906] HASSELBRING—APPRESSORIA OF ANTHRACNOSES 137

organs of Gloeosporium. CLINTON'' regards them as chlamyd-
ospores, They are also briefly described by Von SCHRENK and
SPAULDING"? who add Gloeos porium cactorum to the list of anthrac-
noses producing them. In order to clear up the uncertainty
expressed in the literature regarding these organs, the following
experiments and observations on the appressoria of Gloeosporium
jructigenum are here recorded.
FORMATION OF APPRESSORIA.

As has been said, DE Bary and BiscEen have shown that the
stimulus of mechanical contact is the cause of the formation of
adhesion organs. Regarding the adhesion organs of Gloeosporium
Miss SourHWorTH mentions the fact that they are especially
numerous where a hypha comes into contact with some hard object
like the cover glass. Hatsrep finds that a rich nutrient medium
produces only a meager supply of “special cells,” while pure water
increases their production. In neither case were these suggestions
further investigated. Other writers had suggested in a general
way that “unfavorable conditions” and starvation of mycelium
Cause the formation of the special cells.

Spores were sown in convex drops of water on slides kept in a
moist chamber. Under these conditions the spores germinate
Tapidly, but their behavior varies
according to their position in the
drops. Those which sink to the
bottom of the drop form a short
germ tube, which enlarges into a
found or pear- shaped disc when
: comes into contact with the

ass, :
hs developed into complete adhe, ctv med
sign Orpan ie. i hk P: " germinating in water on glass slides.
-is a brown
Spore-like body, having a thick wall which is perforated on its lower
appressed surface with a very distinct germ pore. The adhesion
Se raiias G. P., Apple rots in Illinois. Univ. of Ill. Agr. Exp. Sta. Bull. o-

bls. 10

B SCHRENK and SPAULDING, The bitter rot of apples. U. S. Dept. Agr.
we Plant Industry Bull. 44. pls. 9. 1903.

=

138 BOTANICAL GAZETTE [AUGUST

organs are so firmly fixed to the slide that they are not easily washed
off by a jet of water. Other spores remain floating in the drops of
water, being held by the surface film. These also germinate readily,
but they never form adhesion discs while the germ tubes remain
free in the water. Other spores were sown in drops of water
placed on the surface of apples. These behaved in the same way
as those on slides. Spores in hanging drops produced mostly mycelia,
since very few germ tubes came into contact with the glass. The
experiment was then varied by substituting beet infusion for the
drops of water. The result was striking. The germ tubes pro
duced no appressoria, but grew out into long hyphae, regardless
of the fact that they were often in contact with the surface of the
glass or with the cuticle of the apple. When sown in nutrient media
of any kind, solid or liquid, the spores of Gloeosporium germinate
and form mycelia directly.

These experiments show that the formation of appressoria |S
induced by a contact stimulus, but in the presence of abundant
nutrient material the germ tube loses its power to react to contact
stimuli, and the formation of appressoria is inhibited. If this were
not the case, the mycelium would react to the contact of evéty
obstacle, such as cell walls or starch grains, which it met in its course
through the tissues, and growth would thus be made practically
impossible. This is illustrated by the behavior of spores in weak
beet infusion. Here the germ tube shows a tendency to form esi
appressorium, but before this is well formed it grows out again
into a mycelial hypha, which immediately repeats the process. In
old agar cultures which have been exhausted, the hyphae form 4
series of thick-walled cells of the nature of appressoria. These do
not have the normal shape, but assume fantastically lobed forms, 5°
closely crowded that they resemble sclerotia-like masses. The
exhaustion of the nutrient material in the agar and the contact
with the glass or other solid particles no doubt leads to the formation
of these masses. ;

GERMINATION OF THE APPRESSORIA.
: A : : ith
The appressoria germinate readily on a slide when covered ee
nutrient solution. The germ tube always emerges from the pe

1906] HASSELBRING—APPRESSORIA OF ANTHRACNOSES 139

on the surface appressed to the glass. By its vigorous growth it
tilts the body to one side (fig. 2).

The process of penetration was observed by sowing spores on
berries of Berberis Thunbergii, which are readily infected by the
fungus, although some other species seem to be
immune. From the pore on the lower flattened side
of the adhesion disc, a slender tube protrudes and
dissolves an arrow channel in the wax covering the
cuticle, Although at first very slender, the hypha
soon becomes larger and dissolves large cavities in
the wax (figs. 3, 4). The fact that these cavities
are more extensive than is necessary for the accom-
modation of the germ tube would seem to indicate
that a solvent is secreted in sufficient quantities
to accumulate on the outside of the infecting hypha.
Finally the cell wall is perforated and the
mycelium branches freely within the cells, at
the same time sending hyphae into the neigh-
boring cells. +The penetration of the germ tube
through the cuticle of the apple has frequently
been observed, although it has not been pos-
sible to follow the mycelium farther, probably
on account of the early collapse of the cells and the consequent

Fic. 2.—Germi-
nating appressoria.

Fic. 3. Fic. a :
Fics. 3, 4.—Infecting hyphae penetrating the cuticle
of berries of Berberis Thunbergit.
Mpa diet of débris. The channel in this case is very narrow
ut well defined, Contrary to former supposition no previous Injury

140 BOTANICAL GAZETTE [AUGUST

or puncture of the fruit is necessary. This is further demonstrated
by the number of infections occurring in apples. In some cases
100 to 200 infections were found on single apples, and recently
Scott's reports the enormous number of 1,000 to 1,200 infections

on single fruits. It is not likely that these represent previous —

mechanical injury to the fruits.
APPRESSORIA IN RELATION TO DISSEMINATION.

The behavior of the appressoria of the bitter-rot fungus under
natural conditions is of interest from a biological standpoint. The
spores of this fungus are imbedded in a gelatinous substance, which
causes them to stick together in waxy masses when dry. By reason
of this condition the spores cannot be distributed by wind. 50
far as known they are entirely dependent for their dissemination
upon rain, although it is probable that insects take an active part
in carrying the spores from tree to tree. Each season the first ge™
eral infection of apples by the bitter rot is due to rain washing the
spores from the limb cankers, in which the fungus hibernates, 1
the apples below. This is plainly shown by the observation that
on a tree the infected apples are distributed within an area that
can be circumscribed by a cone having its apex at the canker, the
source of infection. Furthermore, drops of rainwater, collected
from badly infected trees, usually contain numerous spores of the
bitter-rot fungus. é

Since the rain, at least in many cases, is the chief factor in dis-
tributing the bitter-rot spores, it is of interest to determine the effect
of wetting and drying on the spores, and also the relative vitality
of the spores and the appressoria. It should be stated, that while
the spores are imbedded in their mucilaginous covering, they retain
their vitality for a long time, but not during the entire winter,
as has often been reported. In the latitude of Southern Tilinols,
spores remaining on apples under the trees either germinate** seg
perish long before spring. Spores taken from time to time from
a diseased apple, which was kept dry in the laboratory from August
until January, showed a large percentage of germination as late a>
Nov. 29, but later rapidly lost their vitality.

ott, W. M., The control of apple bitter rot.. U. S. Dept. Agr. Bu
Industry Bull. 93. pls. 8. 1906.
14 See also CLINTON, /. ¢.

r. Pl

Pee a Ret ee ee

1906} HASSEL BRING—AI PRESSORIA OF ANTHRACNOSES I4t

To test the resistance of spores to drying after being freed from
the surrounding mucilage by washing, a quantity of spores was
shaken up with water and then spread out on glass slides which
were allowed to dry. After remaining dry 14 hours, few spores
germinated when again placed in water; after 24 hours, none ger-
minated. At different times during the summer spores were shaken
up in water and sprayed on filter paper, apples, and glass slides, but
it was impossible to cause them to germinate after having been
dried 24~30 hours.

That the appressoria are more resistant is shown by the following
experiment. Appressoria were produced by sowing spores in drops
of water on slides
which were kept in a sc...
moist chamber until jf ge
the following day. {|
The slides were then

allowed to d SHA. \
ry, all f |
a submerge fos Seis

d spores

Fie Fics. 5, 6.—Natural appressoria
formed on the surface of apples.

Fic. 7.—Section showing relation
of adhesion organ to cuticle of apple.

having produced appressoria.
The germination of the appres-
soria was tested from time to
time by covering a slide with
sugar-beet infusion. The ap-
inesulanl pressoria germinated, though
= arty, as late as Dec. 11, when the last slide was used.

oe the hot summer weather the bitter-rot spores germinate
bate is vis In 12-24 hours the appressoria are formed. Under
diately . itons the germ tube is extremely short, since it imme-
ret 2 ss to the formation of an adhesion-disc. From this
sabes sa nea and more resistant organ the infecting hypha dis-
any chils e into the fruit. In badly infected trees the appressoria

€ found in great numbers adhering to the surface of the

142 BOTANICAL GAZETTE [AUGUST

apples. Such naturally formed appressoria are shown in jigs. 5, 6,
while in fig. 7 a single adhesion organ is shown in section.

CONCLUSIONS.

The spore-like organs formed by the germ tubes of the anthrac-
noses are adhesion organs, by means of which the fungus is attached
to the surface of its host during the early stages of infection. They
are not suited for dissemination and therefore are not to be regarded
as spores. The adhesion discs are formed as a result of stimuli
from mechanical contact acting on the germ tubes. When growing
in nutrient media the germ tubes lose their power of reacting to
contact stimuli by the formation of appressoria. Under natural
conditions the appressoria are formed as soon as the germ tube
emerges from the spore.

Notr.—In the same year ATKINSON describes these bodies for a species of
Colletotrichum (C. Gossypii)'5 and suggests that their production in unfavorable
conditions seems to favor the notion that they are resting bodies.

1s ATKINSON, G. F., Anthracnoses of cotton. Journ. Mycol. 6:173-8. pls. 2. 2, 1891.

THE UNIVERSITY OF CHICAGO.

BRIEFER ARTICLES.

NEREOCYSTIS LUETKEANA.
(WITH ONE FIGURE)

This giant kelp is one of the most common, and certainly one of the
most striking algae of the shores of northwest America. Its cylindrical,
hollow stalks, as much as 21™ long, gradually widening from a diameter
of 1°™ below to 10°™ above, surmounted by a bulb as much as 20°
in diameter and provided with a crown of leaf-like fronds 3-9™ long; its
habitat on submerged rocks over which it forms brown patches acres in
extent, a warning to fishermen and pilots, and so dense that only with great
difficulty can one get a rowboat through them; its presence everywhere
in still waters and stranded along shores, torn loose and transported by
Waves and wind, attract the attention of every casual traveler along north
Pacific shores. Two things concerning this plant at once impress the
botanist, viz.: its remarkably rapid growth and its manner of solving the
Problems of life.

1. Growth.—We have here a plant 15-21™ long,’ reported to reach a
length of over go™,? but probably erroneously; MACMILLAN? mentions 80
feet. Harveys states that it is growing at all seasons; fishermen and
pilots, however, say that it disappears in winter. I knew the June condi-
tion of these plants, and I had accurately located several beds of them
hear the Marine Station of the University of Washington at Friday Har-
bor, Wash., during the summers of 1904 and 1905. On March 10, 1906,
I made another trip to these beds with a view to determining whether or
hot this gigantic plant is anannual. The fishermen are partly right. Except
for stragglers here and there, the kelps are gone; while those remaining
were nearly all decayed and loose, with their fronds mostly torn away.
Where the plants were floating freely, the remaining ones were yet in fair
Condition as to decay, as salt water prevents rapid bacterial action; but
it required considerable searching to find a dozen good specimens.

Drifting over the reefs one can see, through a glass-bottomed bucket,
on the bottom 3 to 9™ below, young plants of Nereocystis 1.25 to 2.5™

" SAUNDERs, Algae of Harriman Alaska Expedition. Proc. Wash. Acad. Sci. 3:431-

* ENGLER & PRANTL, Die natiirlichen Pflanzenfamilien 12: 259.

$ Bull. Torr. Bot. Club 26: 273-299. 1899.

*Sea mosses 87,

143] [Botanical Gazette, vol. 42

144 BOTANICAL GAZETTE [AUGUST

long, with bulbs 12 to 38™™ in diameter, and fronds 30 to go°™ long. It
seems that they do not reach the surface the first year, but remain out of
reach of waves, pushing rapidly up in the second season only to die when
winter overtakes them. A growth of about 18™ in the second year, between
the middle of March and the first of June, a period of about 70 days, re-
quires on the average a growth of over 25° a day. The probability is
that it is even greater, for March is cool on Puget Sound, so the growth
would occur chiefly in the latter part of this period. In proof of this

Fic. 1.—Nereocystis Luetkeana.

belief is the fact that the ground was frozen during the whole week succeed-
ing the time of observation; in fact, it was the coldest weather of the whole
winter. Then too, another trip on May 10, 1906, but to a different bed,
revealed none over 6™ long; so it is evident that they had 9g to 15™ ol
stretching before them for the next month. Twenty-five centimeters
day is about 0.175™™ per minute, which is between one-third and one
fourth as rapid as that reported for the bamboo,’ and far above iit ol
ordinary plants. One hardly expects prolonged rapid growth in the
latitude of Puget Sound, but Nereocystis certainly furnishes an example
of it.
5 STRASBURGER eft. al., A text book of botany, English edition, 231- 1993-

per

1906] BRIEFER ARTICLES 145

2. Lije relation.—The shore just below low tide to a depth of 6™ is
taken up by shorter, broad algae, mostly brown, many green, a few red;
limited up shore by the grinding wave-washed rocks as the tide level
varies, and by the baking heat of a summer sun during low spring-tides;
limited downwards by the decreasing sunlight; we find on this strip the
battle ground of the green and brown algae, species against species. Nereo-
cystis, with its tough, flexible, cattle-whip-like stalk 12 to 21™ long, rises
from the bottom in the deeper waters, a veritable Esau, surrendering to
the Jacobs the coveted strip and wresting from the undesired, compara-
tively unoccupied territory beyond, a highly successful existence. The
stalk is firmly anchored to the rocks below by holdfasts covering an area
as Much as 30°™ in diameter. So strong and tough is the stalk, and so
firm the attachment, that often a pull of several hundred pounds is neces-
sary to loosen the plant; and then the stalk more often than the holdfast
gives way; but a large plant, avoiding quiet waters, needs a firm hold,
and one occasionally finds the plants washed ashore with holdfasts dragging
rocks as much as 20°™ in diameter, The admonition to “build upon a
rock” holds for N: ereocystis, and the rock must be a big one; those which
“build upon sand” are washed away before they reach the adult stage.
This is one of the reasons why it grows upon reefs.

Algae love moving water, but few can afford it. Moving water facili-
tates gas exchange by carrying away that ladened with evolved and lacking
In desired gases, and by not depositing suspended materials like quiet
water. A layer of beach washings over a plant absorbs sunlight, one of
the scarcer commodities of marine algae, any diminution of which only
those most favorably located can afford. Nereocystis, by its firm anchorage
and long stalks, surmounted by a bunch of tough blades 3 to 9™ long but
harrow for their length, rides easily in flowing water, and chooses for its
home the rocky, clean-swept, tide-washed promontories, where the current
keeps its blades horizontal.

elow 6™ the brown algae rapidly decrease, and dredging in Puget
Sound shows that below 12™ they are exceptional. They need light. It
is well known too, that the decrease in light downward in water is rapid.
This makes the surface the most desirable location. But shore forms, at
the surface at high tide, are stranded high and dry at low tide; and those
at the surface at low tide are covered at high tide, the depth depending
“pon the difference between high and low tide. This constant change in
Water level is one of the greatest difficulties with which, seaweeds have to
‘ontend. We see at once that marine algae have a very serious problem,
to steer clear of the Scylla of darkness on the one hand, and, on the other,

146 BOTANICAL GAZETTE [AUGUST

at a very short bow-shot’s distance, the Charybdis of tide-line destruction
by wave and sun. Nereocystis has solved the problem by the floating
dock. Its holdfast at the smaller end of the stalk serves as the anchor,
fastened far enough off shore to prevent stranding at low tide; its hollow
bulb, surmounting the larger, hollow end of the stalk is the float; attached
to the bulb are the leaves, constantly at the surface, supple, tough, safe in
storm, current, and varying tide. However, it has minor troubles, since
in creating for its own fronds an excellent environment it has created also
an excellent habitat for other forms as well. It is not uncommon to see
the bulbs and stalks densely covered with delicate red and green algae,
and hydroids and bryozoa. Rising from unoccupied territory, and creating
for its fronds one of the best habitats among marine algae, N ereoc ystis
Luetkeana challenges the respect of the botanist and the lover of nature
THEODORE C. FRYE, State University, Seatile, Washington.

TWO NEW SPECIES FROM NORTHWESTERN AMERICA.

Miss Epira M. Farr of Philadelphia has recently submitted to the
writer a small collection of plants for identification. The collection was
made in the mountainous regions of Alberta and British Columbia, chiefly
in the vicinity of Banff, Lake Louise, Field, etc., during the summers
of 1904 and 1905. Among other interesting rarities there are two which
the writer has been unable to place satisfactorily in any described spea®
These are characterized as follows:

Castilleja purpurascens Greenman, n. sp.—Perennial, more OF less
purplish throughout: stems erect or nearly so, 1 to 3°™ high, usually
several from a multicipital caudex, glabrous or puberulent below, villous
above: leaves sessile, subamplexicaul, linear to narrowly lanceolate, 1-5
to 4.5°™ long, 1 to-7™™ broad, usually attenuate and acute, entire and
undivided or occasionally 3-cleft near the apex, glabrous or the uppet egecrl
what villous-pubescent, 3-nerved; the lowermost leaves much reduced:
inflorescence terminating the stem in a subcapitate raceme, later elongating
to about 7°™ in length, villous-pubescent; bracts ovate-lanceolate to oblong-
ovate, 2 to 2.5°™ long, usually entire, occasionally cleft: calyx 1-5 —s 2.50
long, and as well as the bracts varying in color from a deep purp's""
to’ scarlet and rarely to yellow tinged with red or pink, about equally
divided before and behind, externally villous with glandular hairs ie
mixed; the lateral divisions 2-lobed, lobes obtuse: corolla 2 to 3 lon: .
galea about one-half as long as the corolla-tube, green or greenish-yerr™
on the glandular puberulent back, with scarlet or magenta ©

1906] BRIEFER ARTICLES 147

margins, conspicuously exserted beyond the calyx and floral bracts; lip
usually dark green, 3-lobed, about one-fourth the length of the galea,
commonly protruding through the anterior fissure of the calyx: mature
capsule oblong, 7 to 8™™ long, abruptly acuminate or subapiculate, strongly
compressed laterally, glabrous: seeds about 1.5™™ long, yellowish-brown.

- British CoLumBia: near Field, at an altitude of about 1200™, 7 June, 1905,
Miss Edith"M. Farr, nos. 567, 568 (type), 569, 570, 571, 572, 573, 574 (form
with yellowish inflorescence slightly tinged with red or pink), 575, 576. Type
in hb. Field Museum and hb. Univ. of Penn.

The suite of specimens here cited shows considerable variation in color and

to some extent variation in foliage, but all have the same habit and technical
characters of the flower. The species apparently has its nearest affinity with
Castilleja Elmeri Fernald, from which it differs in being glabrous or essentially
so below, in having a more slender inflorescence, narrower floral bracts, and a
more conspicuously exserted corolla with a somewhat longer galea. The pur-
plish cast of the entire plant with the galea extending well beyond the crimson
°r purplish bracts and calyx renders this an attractive species and easily dis-
tinguished among its numerous allies.
_ Senecio (§AuRer) Farriae Greenman, n. sp.—An herbaceous peren-
Malt to r,sdm high: stem erect or ascending, branching from near the
base, glabrous except for a persistent white tomentum in the leaf axils;
branches few, relatively long and terminated by a single head: basal
leaves ovate to slightly obovate, the blade 1 to 3°™ long, 1 to r.5°™ broad,
rounded at the apex, crenate-serrate to subentire, contracted at the base
into a narrowly winged petiole equaling or exceeding the blade, glabrous
or nearly so; the lower stem leaves sublyrate or more or less irregularly
Pinnatifid, the upper reduced to entire bracts: heads about 1°™ high,
radiate: involucre campanulate, slightly calyculate, tomentulose at the
base; bracts of the involucre usually 21, linear-lanceolate, about 8"™
long, nearly or quite equaling the flowers of the disk, acute, reddish tipped:
ray-flowers 12 to 14; rays orange-yellow; disk-flowers numerous.

ALBERTA: near Banff, altitude 1500™, 8 June, 1904, Miss Edith M. Farr.
Type in hb. Uniy. of Penn., fragment and photograph in hb. Field Museum.—

. M, GREENMAN, Field Museum of Natural History, Chicago.

CURRENT LITERATURE,
BOOK REVIEWS.
Plant response.

No suBJECT is more fascinating than the responses of plants to stimuli; and.
though the mechanisms involved are often much simpler than in the case of
animals, no subject is more difficult. Papers dealing with limited topics in this
field are constantly appearing; one feels some surprise at seeing a large volume
of new researches dealing with the matter in the most fundamental fashion.
The surprise is increased when it is seen that the author is one whose name 1s
new in the literature of plant physiology and whose nation is fond rather of
speculative philosophy than of scientific observation. Professor JAGADIS CHUN-
DER Bose of Presidency College, Calcutta, published in 1902 a volume on Response
in the living and non-living, in which he pointed out many parallels between the
“irritability” of organisms and of other bodies. But this volume seems not 10
have attracted general attention among physiologists; and some of those who
read it were inclined to discount the parallelism as one suggested rather by
philosophic bias than scientific induction. ;

On opening this new work? the plant physiologist will be inclined to think
it some volume on muscle-response in animals, the numerous graphs being quite

muscle,

animal physiology and in the methods of research in vogue for pulse and edi
L ep wh Py Se fea corde

detecting before unsuspected (or at least unre

responses in plants. d
But he has done much more than merely apply the existing apparatus 4"
methods. He has employed new methods and has devised new and ingenious
apparatus for automatically recording responses. For example, there ae
described many clever minor adaptations of the optic lever and various electri¢

evices; and among the major ones may be enumerated the kuochangee
io

‘ ‘ : wee §yo-

« Bose, J. G., Plant response as a means of physiological investigation- Co.

pp. 781. figs. 278. London, New York, and Bombay: Longmans, Green,
1906.

148

1906] CURRENT LITERATURE 149

balanced so as to record the average rate of growth as a straight horizontal
line, any fluctuation, even the slightest, showing as deviation from this horizontal
line; and the magnetically controlled heliotropic recorder, utilizing the optic
lever yet avoiding the use of light within the plant chamber, except that which
is the stimulus. .

One striking feature of all the apparatus, aside from its ingenuity, is the
high magnification which it permits. This is at once an advantage and a
danger; but consistent results, if critically controlled, ought to guard against
_ Serious error.

The book is not without errors, both of reasoning and fact, into which the
author has fallen by reason of some unfamiliarity with his materials. No one
could justify himself in accepting as established all the deductions from the vast
number of experiments detailed in the book; they must be verified sooner or
later by other observers. To our knowledge some have already been repeated
(some of those, for instance, on the variation in electric potential resulting from
stimulation, in Dr. HarPER’s laboratory at the University of Wisconsin) with
concordant results. But whatever the future may show as to the accuracy of
details, this book may be acclaimed as a path-breaking one; for it shows a method
of attack and a refinement of instrumentation for the study of the phenomena
of irritable reactions in plants that are sure to be of the utmost service. It is
rather remarkable, indeed, that we have had so few recording instruments in
the service of plant physiology, and that we have been content, for example, with
magnifications of 10 or 20 times in the auxanometer, where Bose finds 1,000 or
€ven 10,000 practicable with his crescograph. .

The fundamental thesis of the book is that the underlying response to stimuli
isalike in plants and animals; is alike in all plants and in all parts, with all stimuli;
and is universal. This response, however diverse its modes of expression, con-
sists of two very simple and well-defined factors, contraction and expansion;
the former the direct effect of stimulation, the latter the indirect. Mechanical
response is always by a concavity of the more excited side and may or may et
ccur; electrical response can always be detected; growth is merely a multiple
Tesponse; at death (near 60° C. for phanerogams) a sudden and irreversible
molecular change takes place, attended by an excitatory contraction. The
Phenomena of fatigue, of staircase response when the organ is at first sluggish,
of tetanus, of the polar effects of electric currents, of variation in electric poten-
tial, of transmission of stimuli, and of rhythmic responses—all can be demon-
strated in plants as in animals, giving evidence in greater detail of the essential
unity. With this Bose is more impressed and on it he lays more stress than the
casé demands; for it is by no means so novel an idea to botanists as to most
zoologists.

Of all the fifty chapters in the book none are so unsatisfactory as those on
the ascent of sap, constituting. part V. Bose holds that he has demonstrated
the ascent of water to be due to the physiological activity of living cells whose
Suctional response is coordinated by the passage from point to point of an exci-

15° BOTANICAL GAZETTE [AUGUST

tatory reaction which drives water in one direction.? But some of his reasoning ~
is radically defective, the chapters are full of assumptions, and his experiments
are inconclusive. Indeed, he hardly seems to know how difficult a problem he
is attacking, and he goes at it with the naiveté of a novice. Such work really
tends to prejudice one against the whole book; and caution is necessary, for
there are other weak spots. In spite of these, the suggestiveness, the ingenuity,
and the enormous labor displayed impel us to give this a most cordial
reception. And we shall await with much interest a promised volume on the
electrophysiology of plants.—C. R. B.

MINOR NOTICES.

N. Am. Uredineae.—The second: part of Hotway’s photomicrographs of
plant rusts has just appeared, having been delayed several months by a printer's
strike. The general character and purpose of this publication were described
in this journal*+ upon the appearance of the first part. The present part con-
tinues the genus Puccinia through eleven host families, ending with Rosaceae.
The photogravure plates carry out fully the promise of the first part—J. M. C.

Schneider’s Handbuch.—The fifth part of the Jllustriertes Handbuch der
Laubholzkunde’ concludes Drupaceae and includes Pomaceae, and ends the first
volume. There are 128 text figures, and a volume index of genera.—J. M. ©

NOTES FOR STUDENTS.

The ascent of water.—After GopDLEWSKI’s interesting theory of the relay-
pump action of the medullary rays in lifting water seemed to have been completely
overthrown by STRASBURGER,® who found water still ascending for weeks after
treatment calculated to kill living cells, the participation of living cells in lifting
water found a champion on theoretical grounds in SCHWENDENER.? But Ever.
FERS hardly dared more than to suggest that they might be. of importance

2 See in this connection reviews of other recent papers below.

3 Hotway, E. W. D., North American Uredineae, Vol. I. part II. 4to. pp- ie
pls. 11-23. Minneapolis, 1906. $2.00.

4 Bor. GAZETTE 40:459. 1905.

5 SCHNEIDER, CAMILLO Kart, Illustriertes Handbuch der Laubholzkunde-
Fiinfte Lieferung. Jena: Gustav Fischer. 1906. M

6 STRASBURGER, E., Ueber den Bau und die Verrichtungen der Leitungsbahnes
in den Pflanzen. Histologische Beitrige 3. Jena, 1891. Ueber das Saftsteige”-
Histologische Beitrage 5. Jena, 1893. _

7 SCHWENDENER, S., Zur Kritik der neuesten Untersuchungen iiber das Saftsteige™-
Sitzb. Berliner Akad. 44:911-946. 1892. Gesammelte Unters. 1: 256-297- Raoett®
Ausfiihrungen iiber die durch Saugung bewirkte Wasserbewegung in der Jamin —
Ketten. Sitzb. Berliner Akad. 45:835-846. 1893. Gesammelte Unters. 7°

15- 1898

8 PreFFER, W., Pflanzenphysiologie 1: 203. 1897.

1906] CURRENT LITERATURE I51

the maintenance of normal conditions in the conducting tissues. Then UrspruNG
5b

rallied to the support of SCHWENDENER with experimental work, and in a paper

published two years ago® contended that the living cells, either by maintaining
the conducting system in condition or by actually lifting, had an important share
in the ascent of water. His experiments were carried out on small plants mainly,
and he ventured no generalization.

In a more recent paper’® he reviews critically the direct and incidental experi-
ments of others on this subject, replies to objections raised against his earlier
paper; and details further experiments intended to ascertain the precise rdle of
living cells. The author adopts a rather hypercritical attitude toward previous
results, as is well illustrated by this reasoning regarding girdling: ‘‘If at the
base girdling 14m Jong is borne without injury, it does not signify that this would
be the case also at the apex; and if girdling 14™ long does not interrupt the
conduction of water, it is not proved that this would not occur with girdling one
or two meters long. Hence it follows that the bark (Rinde) must be entirely
temoved if one wishes to form a judgment as to its share in the ascent of sap;
and even then one can at most only recognize that it may be dispensed with—
not that under ordinary conditions it takes no part in the ascent of sap.”

By liberal discounts Ursprunc arrives at the conclusion that all previous
researches on this point speak in favor of the participation of living cells in rais-
mg water. Even the experiments of SrRASBURGER, which have been interpreted
as flatl¢ contradictory to such an idea, are counted as offset by his finding that
the leaves die after one actually kills 10° of the stem. For, according to UrR-
SPRUNG, the cooperation of living cells throughout the entire length of the plant
1S Necessary; but a small fraction of the conducting system suffices to supply
Water if in this region the wood cells are living; whereas the whole is inadequate
to furnish enough water when they are killed. These living cells do not merely
keep the conducting tissues in good condition; they ‘cooperate in the production
of the lifting force,” and the component which they furnish is of great significance
i comparison with the “purely physical.’’ A notable exception is the beech, in
Whose older parts the cells of the bark are without influence, “‘and even in the
youngest parts such interaction is insignificant.” It is hard to conceive how
the living cells in the bark, being outside the water paths, can participate in the
work of raising water, and harder still to imagine that they do so in certain plants
and not in others,

STEINBRINCK attacks the problem from the ‘purely physical” side,** and

— As, Untersuchungen iiber die Beteiligung lebender Zellen am Saft-
- Beihefte Bot. Cent. 18:145-158. 1904.
Mice Die Beteiligung lebender Zellen am Saftsteigen. Jahrb.
* 42:503-544.- 1906,
*t STEINBRINCK, C. Untersuchung iiber die Kohiasion strémender Flussigkeiten
5 Wi

. te auf das Saftsteigeproblem der Baume. Jahrb. Wiss. Bot. 42:579-
5+ 1906,

152 BOTANICAL GAZETTE [AUGUST

seeks to extend our knowledge of hydrodynamics. He examined the cohesion
of water by means of the supersiphon, i.e., a siphon whose legs are so long
as to permit the use of columns of liquid too high to be raised by atmospheric
pressure, to which (STEINBRINCK thinks erroneously'?) the action of the common
siphon is ascribed. e attempted to ascertain the cohesion of water under
various conditions, and met sometimes with such capricious behavior of his
apparatus that, more than ever by this experience, he is convinced of the necessity
for much more extended physical knowledge before the problem of the ascent
of sap can be solved. The reinvestigation of the tension of gases in fern and
other sporangia (which he finds nearly at atmospheric pressure) and of their
disappearance when the sporangia are wetted, shows that these phenomena do
not fall in with any known physical laws; and as these structures plainly contain
only dead cells the problem cannot be obscured by dragging in “vital activities”
and remains at present inexplicable. How much more caution, then, is neede
in the more complex problem of sap movement!

STEINBRINCK finds that a water filament 2™™ thick, moving at the rate of
2m per second, bears a pull of four atmospheres, its tensile strength increasing
with diminishing size and rate of flow. Such filaments bear even violent shaking,

0° to 35° C.). By ingenious experiments he shows that cohesion may act through
membranes, such as the partitions that interrupt the tracheae. As for therobjec-
tion to the cohesion theory on account of the Jamin-chain condition, he suggests
caution on account of deficient physical knowledge, enforcing this by citing the
case of gas absorption in the opening sporangia already alluded to. He does
not deny the participation of living cells, but can form no conception of the
manner in which they act.

Ewart, recognizing that water is a liquid of definite viscosity and that the
channels through which it moves are small, thereby offering great resistance, has
endeavored to ascertain the amount of this resistance in definite cases, and the
possible means by which is generated the force necessary to raise water at the
required rate.t3 He finds that the flow of water through open vessels is in accord
with PotsEUILLE’s formula deduced from flow through rigid tubes; hence
velocity is proportional to the pressure and to the square of the radius of the
tube, and inversely proportional to the length of tube and viscosity of the liquid.
The total resistance in erect stems corresponds to a head of water 6 to 33 (for
shrubs and small trees) or 5 to 7 (for large trees) times the height of the plant.
Hence, in the tallest trees, the pressure required may be as much as 100 atme®
pheres. The maximal osmotic suction of leaves in an elm 187 high was 2-3

12 STEINBRINCK, C. Ueber dynamische Wirkung innere Spannungsdifferen2™
etc. Flora 93:127-254. 1904.

13 Ewart, A. J., The ascent of water in trees.
B. 198: 41-85. 1905.

Phil. Trans. Roy. Soc- London

1906] CURRENT LITERATURE 153

atmospheres, with a total resistance to flow in the trunk of 1o-12A. ‘“‘It appears,
therefore,” concludes Ewart, “that to maintain flow, a pumping action of some
kind or other must be exercised in the wood, for which the presence of active
living cells is essential... . . There is no known means by which these cells
can directly pump water in a definite direction. . .. . It is suggested that the
wood parenchyma cells, by the excretion and reabsorption of dissolved materials,
may bring into play surface tension forces within the vessels of sufficient aggre-
gate intensity to maintain a steady upward flow, and to keep the water of the
Jamin’s chains in the vessel in a mobile condition, ready to flow to wherever
Suction is exercised.”

But STEINBRINCK declares himself (J. c.) unable to form any conception of
how such an action can be produced, and LARMOR objects'+ on purely mechani-
cal grounds, saying: “If the osmotic gradient, assisted by capillary pull at the
leaf orifices, is insufficient to direct a current of transpiration upward, capillary
alterations inside the vessels, arising from vitally controlled emission and absorp-
tion of material from the walls cannot be invoked to assist.” He suggests that
osmotic changes in the vessels, of peristaltic character, might do; but he appar-
ently does not know that osmotic phenomena do not occur in sap vessels. As
a physicist, he inquires whether there is a sufficient stock of energy in the stems
for the pumping work required; and he renews the eminently plausible suggestion
that the work is done where the external energy is received, viz., in the leaves.

It cannot be said that these researches have solved the problem of water
Movement. But each in its own way has added something to our knowledge.
The more hopeful lines seem to be in determining physical factors and studying -
more closely the dynamics of the question.—C. R. B.

Gymnosporangium galls.—The anatomical changes induced by Gymno-
Sporangium clavariaeforme and G. juniperinum on the twigs and teaves of their
host, Juniperus communis, have been investigated by L RE'S with the
following main results. The mycelium of G. clavariaeforme inhabits the cortex
and phloem regions, but does not penetrate into the wood. The cells of the
Cortex are multiplied and enlarged so that all lacunae. are obliterated, resulting
'n @ general hypertrophy of this region. The formation of collenchymatous
Ussue is almost entirely suppressed. In the phloem region the medullary rays
undergo the most marked transformation. Not only do the rays themselves
become More numerous, but the cells composing them are also greatly increased
'n number, so that this tissue is likely to make up about one-half the volume of
the bast region. The sieve tubes, parenchyma, and bast fibers retain their
"normal succession, but owing to the great increase in parenchyma from the rays
and from the increased volume of the bast parenchyma, the course of the sieve
BRR pee
‘ “4 Larmor, J., Note on the mechanics of the ascent of sap in trees. Proc. Roy.
Soc. B. 76: 460-3. 1905.
*S LAMARLIERE, L. GENEAU DE, Sur les mycocécidies des Gymnosporangium.
Sc. Nat. Bot. IX, 2:313-350. pls. 8-12. 1905.

Ann.

154 BOTANICAL GAZETTE [AUGUST

tubes and bast fibers becomes distorted and irregular. The cambium ring also
is broken and irregular from the fact that uniform differentiation into phloem and
xylem no longer occurs. In the wood the medullary rays undergo transformation
as in the phloem, becoming irregular masses of parenchymatous storage tissue.
he wood is also considerably enlarged. :

In G. juniperinum the changes are similar but less marked, the greatest
changes in the medullary rays being near the periphery. The sieve tubes are
mostly suppressed and the xylem is somewhat reduced. In the leaves the chief
change induced by this fungus is the transformation of the spongy parenchyma
into palisade-like tissue. The observations of this writer agree in detail with
the more extensive account of WOERNLE, wh llent paper on the anatomical
changes induced by both the European and American species of Gymnospo-
rangium is nowhere cited or referred to in the article.

As a general result of the effects of the fungus on its host, LAMARLIERE points
out the tendency toward “parenchymatization,” i. e., a tendency of the cells
to remain in their more undifferentiated form, a phenomenon from which he
draws a parallel to tuber formation—H. HAssELBRING.

Dioecism among Mucorales.—In continuation of his studies of dioecism
among the Mucorales, BLAKESLEE?® has recently investigated the extent to which
differentiation of sex occurs in the spores from germ-sporangia obtained from zyg0-
spores. The principal results contained in the paper are as follows. The germ-
sporangia of the | pecies Sporodinia grandis and Mucor I (undescribed)
contain but a single kind of spores, which produce mycelia again capable of form-
ing zygospores. With the heterothallic species the case is different. Here spores
in the germ-sporangium may be either all (+) or all (—), or (+) and (—) may
be mixed. Of the species tested, Mucor mucedo produces all (+) or all os
spores in its germ-sporangia, showing that a segregation of sex takes place at
some period previous to the formation of spores. In Phycom-yces nilens, howevet,
(+) and (—) spores are mixed in the same germ-sporangium, together with
others that show a tendency to produce a homothallic strain. The mycelia of
the homothallic strain are characterized by the production of irregular contorted
growths to-which the writer gives the name. pseudophores. The production of
sporangia on these mycelia is very limited. The spores from them show a Segre”
gation into (+) and (—), and others reproducing the homothallic strain.

The reading of this paper is made somewhat difficult partly through lack of
clearness in style, which is as essential in scientific exposition as is accuracy i
investigation, and partly through the loose use of terms introduced by the author
himself. The terms heterothallic and homothallic as used in the earlier papers
on zygospore-formation apply to the condition of sexual differentiation of
individuals within a species, strain, or form, being equivalent to dioecious a
monoecious. While it is possible to speak of a heterothallic species or TA :
ah ioe ae ucorineae. Annales

Py Rs |

16 BLAKESLEE, A. F., Zygospore germinations in the M
Mycol. 4: 1-28. 1906.

1906] CURRENT LITERATURE 155

is difficult to see how this conception can be applied to individual mycelia or to
Spores, or even to the process of germination, as is done repeatedly by the author.
Perhaps the introduction of new terms is superfluous in this case, for the idea is
well expressed by the older terms dioecious and monoecious. These are used
in reference to algae, where the condition thus designated exists.—H. HAsset-
BRING.

Fixation of nitrogen.—The Agricultural Research Association, a Scottish
society which has its station at Glasterberry near Aberdeen, has published in its
Report for 1905 a paper by the Director of Research, THomMAs JAMIESON,'? Chev.
Fr., F. I. C., which is supposed to overthrow the current knowledge as to the
fixation of nitrogen by the root tubercle organisms and to prove that plants of
many sorts utilize the nitrogen of the air directly by means of the hairs with which
the leaves are furnished. The laudations with which this pretended “‘research”’
was received at the annual meeting by men even more ignorant of the subject
than the “director of research,” are really worthy of a place in comic literature,
were it not for its serious side in giving local currency at least to foolish notions.

The “research” itself is its own condemnation, and shows the ‘‘director”’
to be as ignorant of chemistry as of the physiology and anatomy of plants. Here
1S a serious society in Scotland, spending money for that which is not bread,
lauding an imposture as a wonderful discovery, publishing a report with twelve
colored plates illustrating the ‘‘albumen generators” imagined by a man who does
not know the difference between surface hairs and the spiral tracheae of ‘Holly
laurifolia”! Further it summarizes the previous ‘‘leading results” of this same
“director; ” among which we note the discovery that there is “‘an aperture in
root hairs by which the absorption of insoluble matter is explained;”” and that
the “feathery structures in the flowers of cereals and grasses are not essential
Parts of the pistil but serve to drive out the anthers to the air”!

_ Yet we can hardly bring a railing accusation against the misled members of
this society when our own postoffice department has had recently to deny the
use of the mails, to prevent our own people from being swindled, to a rascal
Who is advertising “vineless potatoes,” that produce a large crop of tubers when
Planted in wet sawdust and watered with “potatine” at $4.50 per! Truly, some
botanical training might save the farmer from his foolish as well as his knavish
friends.—C. R. B. .

Corky celltayers in monocotyledons.—MULLER describes® in detail the

cutinized membranes in the root and stem of Convallaria majalis, viz., epiblem
“overing the root-cap, intercutis of greater or less thickness in the cortex of root
WR wer ne ee

; *7 JAMIESON, THomas, Report for rg05 to Agricultural Research Association.
vO. pp. 8r. 1905.

di ® Mttter, Hewrrcy, Ueber die Metacutisierung der Wurzelspitze und iiber
ms © segaen Scheiden in den Aehren der Monocotyledonen. Bot. Zeit. 64:53-84-
+ J+ 1906

156 BOTANICAL GAZETTE [AUGUST

and rhizome, endodermis, and epidermis. The microchemical reactions for
each of these layers are given. A process called ‘“‘metacutinization” is des-
cribed, which involves all the outer cells of a root-tip, and occurs at the end of the
growing season. Four stages in the development of the endodermis are dis-
tinguished, following KRorMER, viz., embryonic, primary (characterized by
presence of CASPARY’s points), secondary, and tertiary (showing suberization
and lignification of a large part of the wall). The endodermis of the root does
not usually pass through more than the first two stages. The writer brings
together the information available concerning the presence or absence of an
endodermis in monocotyledonous stems, and a survey of the tables shows that
in about 60 per cent of the species an endodermis is present in the underground
stem, while only in Medeola and Scindapsis has an endodermis been reported
for the aerial stem. The relation of the starch sheath of aerial stems to the
endodermis of rhizomes was also studied, and the writer failed to establish an
actual continuity between the two layers. The function of the endodermis is
said to be the transfer of water and food between the central cylinder and the
cortex, and the increasing cutinization is associated with the necessity for check-
ing the movement of solutes in the radial direction —M. A. CHRYSLER.

Items of taxonomic interest.—H. D. House (Muhlenbergia 1: 127-131. 1906)
publishes several changes in the nomenclature of Orchidaceae, and describes 4
new Californian species of Dichondra—A. A. HELLER (idem 134) publishes @
new Californian species of Ribes.—Under the editorship of Icn. URBAN (Engler's
Bot. Jahrb. 3'7:373-462. pl. 9. 1906) a fascicle of 18 contributions describing
new Andean plants has been published, among which the following new genera
appear: Orchidotypus (Orchidaceae), by F. KrAnziin; Laccopetalum (Ranun-

culaceae), by E. Ursricu; Belonanthus and Stangea (Valerianaceae), by P.
Pricer (idem,

has described 2 new genera from Madagascar: Cloiselia (Compositae) and
Stenandriopsis (Acanthaceae).—R. M. Harper (Bull. Torr. Bot. Club 33-229"
245. 1906) has described new species from the coastal plain of Georgia under
Sporobolus and Nymphaea.—W. H. BLANcHaRD (Rhodora 8:95-98. 1906) has
described two new species of Rubus from New England, both of them high black-
berries—A. ZAHLBRUCKNER (Ber. Deutsch. Bot. Gesell. 24: 141-146. ft. 10.
1996) has described a new genus (Lindauopsis) of parasites in the hymenium of
lichens.—R. SCHLECHTER (Bot. Jahrb. 39: 161-274. figs. 13-23- 1906), in com
pleting his account of New Caledonian plants, describes the following new engine
Menepetalum (Celastraceae), Acropogon (Sterculiaceae), Memecylantus
Pachydiscus (Caprifoliaceae).—J. M. C.

Double fertilization in Carpinus.—In 1893 Miss BENSON published her oe
paper on the embryology of the Amentiferae. This is now followed by a seco®!

1906] CURRENT LITERATURE 157

paper,*® dealing especially with the behavior of the pollen tube in connection with
double fertilization in Carpinus Betula. As the previous paper pointed out, this
form is chalazogamic, and usually has several embryo sacs, which develop caeca
that penetrate deeply into the chalazal region. The course of the pollen tu
varies considerably, but usually it enters the embryo sac at the base of the caecum.
Premature arrival of a pollen tube results in more or less branching and coiling
about the sacs; and belated pollen tubes also occur, long after fertilization has
been accomplished. The polar fusion nucleus is in the caecum, and as the
pollen tube passes it one of the male cells (probably the one farthest from the
tip) is discharged through a small spur-branch, the other one being discharged
upon the arrival of the tip in proximity to the egg. Sometimes the spur-branch,
containing a male cell, develops sufficiently to discharge it for the fertilization of
the egg of an adjacent embryo sac, in this case triple fusion not occurring. The
paper also presents a somewhat elaborate comparison of Carpinus and Casua-
rina, as the basis of a suggestion that the latter genus should be regarded as a
subfamily of Betulaceae.—J. M. C.

Dust spray vs. liquid—CranDALL”° reports the results of a very thorough
study of the comparative merits of the dust spray and the ordinary liquid Bor-
deaux mixture against the scab and sooty blotch of apple and the codling moth
and curculio of apple. The dust spray cost about 52 per cent less than the
liquid spray and there was further gain in the reduced weight of material to be
transported about in the orchard. On the contrary there seemed to be no differ-
ence in the thoroughness of application under similar conditions, and the work-
men were unanimous in considering the liquid spray the least disagreeable one
to apply. And then as to the final and most important test, that of efficiency,

RANDALL says, in conclusion, “The results of the experiments are sufficiently
decisive to warrant the conclusion that dust spray is absolutely ineffective as a
Preventive of injury from prevailing orchard fungi, and that it is considerably
less efficient as an insect remedy than is the liquid method of applying arsenites. .
—E. Meap Wiicox.

Nature of starch.—In a recent article, FIscHER?! scouts the idea suggested
y CzarEK? that starch may be a mixture of colloidal and crystalline materials,
Saying that so far as he knows there is not the slightest evidence for such a belief.

buti ° BENSON, Marcarer, SANDAY, ELIzABETH, and BERRIDGE, Emity, Contri-
Uutions to the embryology of the Amentiferae. Part II. Carpinus Betula. Trans.
inn. Soc. London Bot. II. 7: 37-44. pl. 6. 1906.
a. C. S., Spraying apples. Relative merits of liquid and dust appli-
- Bull. Ii. Exp. Stat. 106: 205-242. pl. I-9. figs. I-5- 1906.
*« Fischer, Huco, Ueber die colloidale Natur des Stirkekérner und ihr Ver-
halten 8egen Farbstoffe. Beihefte Bot. Cent. 181: 409-432. 1905-
*? Czapex, F., Biochemie der Pflanzen I. Jena 1904.

158 BOTANICAL GAZETTE [Aucust

He does not refer to the work of KRAEMER?3 or of MAQUENNE and Rovx,?4 who
independently and from very different standpoints have found evidence of such
a mixture. Since starch shows seven characteristic colloidal properties and
only two crystalline properties he concludes that it is a colloid.

The author discusses at length the theories of staining with anilin colors,
dismisses as wrong the adsorption theory, and concludes that, while in some
cases, as in the staining of proteids, the reaction may be largely chemical, in most
cases the taking up of the color is by solution, dyes not soluble in water being:
soluble in starch. He further concludes that the solution is a liquid and not a
solid solution, the colloidal starch in the swollen grains being in a liquid state.—

Heterospory in Sphenophyllum.—This genus has been regarded as strictly
homosporous, but THopAy?5 now describes and figures a section through the
strobilus of 5. Dawsoni which shows two adjacent sporangia, one of them con-
taining spores of uniform size, the other containing fewer and larger spores,
among which are seen numerous very small aborted ones. These contrasting
sporangia certainly suggest heterospory, but the largest of the supposed mega-
spores has only about 1.5 times the diameter of the spores of the other sporan-
gium. It will be remembered that in Calamostachys Casheana the megaspores
are only three times as large as the microspores, and this was felt to be a remark
ably small difference.—J. M. C.

Proteid metabolism in the ripening barley grain.—The first section of a papet
to consist of three has been presented by ScCHJERNING.?° A short notice to call
the attention of physiologists is appropriate here, but the reliability of the methods
and conclusions must remain unconsidered. The author finds that spectes,
variety, or type per se do not affect the chemical composition of the dry matter of
the grain so far as the nitrogenous and mineral constituents are concerned.
the grain develops to maturity there is a constant tendency toward equilibrium
between the nitrogenous constituents, which is established at maturity and which
is not disturbed during subsequent storage except in the case of certain albu-
mins.—RAYMOND H. Ponp.

23 KRAEMER, HENRY, The structure of the starch grain. Bot. GAZETTE. 34:
341. 1902. :

24 MAQUENNE et Rovx, Sur la constitution, la saccharification et la rétrograd
ation des empois de fécule. Comptes Rendus Acad. Sci. Paris 140: 130371308. cai

2s THopay, D., On a suggestion of heterospory in Sphenoph yllum Dawson
New Phytol. §:91-93. figs. 14. 1906.

26 SCHJERNING, H., On the protein substances of barley, in the grain itself and
during the brewing processes: First section: On the formation and transformation
of protein substances during the growth, ripening, and storage of barley. Compt-
Rend. Lab. Carlsberg 6: 229-305. 1906

1906] CURRENT LITERATURE 159

Lolium-fungus and smut.—In a short paper FREEMAN?’ points out the proba-
bility of relationship between the fungus of Lolium temulentum and the smuts.
Partly by reason of the facts discovered by Mappox, and later independently
discovered by BREFELD and by HeEckE, that the loose smut of wheat and the
smut of barley can infect the young ovary directly, and that these grains, appar-
ently normal, produce smutted plants, he is led to the belief that the Lolium-
fungus is a smut. The behavior and appearance of the smut-mycelium in these
mbryos is very similar to that of the Lolium-fungus, and strongly suggests a
relationship between that fungus and the smuts.—H. HAsSELBRING.

Contributions from Gray herbarium.?*—In the most recent contribution
of this series, RoBinson has published some hee of his studies in the Eupa-
torieae. There is a revision of Piquieria species being recognized, 4 de-
scribed as new, and a new sub-genus (Erythradenia) oN eN also a revision
of Ophryosporus, 17 species being recognized. Under the genus Helogyne its
Synonyms are discussed, and its 4 species described (one of them is new). A
fourth part of the contribution gives diagnoses and synonymy of Eupatorieae
and of certain other Compositae which have been classed with them, among
which appear descriptions of 6 new species of Eupatorium.—J. M. C. :

N. Am. Characeae.—RoBINsoN?? has published a synopsis of the North
American species of Chareae, one of the two subfamilies of Characeae. Of the
four genera making up this subfamily, only Chara has been collected in North
America. Within the range assigned, 50 species are described as belonging to
this genus, 16 of which are characterized as new. —jJ. MC:

Assimilation of free nitrogen by fungi. From a discussion of = results of

than bacteria. The article is useful in that it brings together all the l‘ierature
telating to this subject.—-H. HassELBRING.
arate nen

*7 FREEMAN, E. M., The affinities of the fungus of Lolium temulentum L. Annales
Mycol. 4: 32-34. 1906.

7° Ropinson, B. L., Studies in the Eupatorieae. Contributions from the Gray
Herbarium of Harvard University. N.S. No. 32. Proc. Amer. Acad. 42:1-48. 1906.

*° RoBINson, C. B., The Chareae of North America. Bull. N. Y. Bot. Gard.
4°244-308. 1906

HEINZE, BERTHOLD, Sind Pilze imstande den elementaren Stickstoff der Luft

2U verarbeiten und den Boden an Gesamtstickstoff anzureichern? Annales Mycol.
4: 41-63. 1906.

NEWS.

THE UNIVERSITY OF VERMONT has conferred the degree of doctor of science
on Mr. C. G. Princie, keeper of the herbarium of the university —SCcIENCE.

. Henry S. Conarp, professor-elect of biology in Randolph-Macon
College, has resigned to accept an appointment as professor of botany in Iowa
College, at Grinnell, to succeed Professor Frnx.

Proressor R. B. WYLIE, professor of biology in Morningside College, has
been appointed assistant professor of botany in the University of Iowa, where he
is to have especial charge of the work in plant morphology.

THE APPROPRIATION for the Department of Agriculture for the fiscal year
beginning July 1, 1906, aggregates $9,932,940. Among the items of interest 0
botanists are the following: Bureau of Plant Industry, $1,024,740; Forest Ser-
vice, $1,017,500; Agricultural Experiment Stations, $974,860; Division of
Publications, $248,520; Bureau of Soils, $221,460; Biological Survey, $52,0;
Library, $25,880.

For Two YEARS the State Weather Service of Maryland has been carrying
on a Botanical Survey of the State under the direction of Dr. FORREST SHREVF,
Johns Hopkins University. During the present summer two parties are 1?
the field: one under Dr. SHREVE, working in the Appalachian valley; and ~
under Mr. FREDERICK H. Biopcerr, Maryland Agricultural College, working
in the Blue Ridge region.

Tue Orrice of Experiment Stations of the United States Department of
Agriculture has undertaken the preparation of a complete list of the books written
by agricultural college and experiment station men in the United States. As a
heritage from the Paris and St. Louis expositions the Office has a set of about
two hundred books by experiment station men. A list of these and of a few
others by the same authors has been prepared, and assistance is requested 1m
completing the list. The Office desires to get copies of such books as are not
now in its collection, so far as this is possible.

--THE Association internationale des botanistes decided last year at Ven
to form an international organization to advance the interests of agriculture as
horticulture by the selection, introduction, and distribution of plants Ue

84 rue de Grenelle, where it is expected to organize for this purpose @ ge

section of the Association and to devise means for attaining promptly te

in view. M. Patipre L. pe Vitmorin is organizing this meeting, which pee

promise of being successful, inasmuch as the cooperation of many savants prae

ticiens and botanical gardens is already assured.
160

No. 3

September, 1906

NRC NECA

Editors: JOHN M. COULTER and CHARLES R. BARNES _

wipe

CONTENTS |

Differentiation of Sex in

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Che Botanical Gazette

A Montbly Journal aan all Departments of Botanical Science
_ Edited by JoHN M. CouLTER and CHARLES R. , with the cake of other members of the
botanical staf of the Pnivesaity of Chic
i Vol, XLII, No. 3

Issued October 2, 1906

ot ~ ee!
a

CONTENTS — |

: DIFFERENTIATION OF SEX IN THALLUS GAMETOPHYTE AND SroROPmIYTE,
4 (WITH PLATE VI AND THREE FIGURES). Albert Francis Blakeslee -

- I61

4 A STUDY OF THE VEGETATION OF THE MESA REGION EAST OF PIKE’S PEAK:

f THE BOUTELOUA FORMATION. II. DEVELOPMENT OF THE FORMATION (WITH

; SIX FIGURES). AH, LZ. Shantz - op See eee ee ee:

; CORTINARIUS AS A MYCORHIZA-PRODUCING isheh Sdeditt ONE Revae Oa «

a Kauffman : - - -208
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VOLUME XLII NUMBER 3

BOTANICAL Gaver

SEPTEMBER, 1906

DIFFERENTIATION OF SEX IN THALLUS GAMETO-
PHYTE AND SPOROPHYTE.*

ALBERT FRANCIS BLAKESLEE

(WITH PLATE VI AND THREE FIGURES)

IN a recent article (5) the writer has given a somewhat detailed
account of zvygospore germinations in certain species of the Mucorineae.
The purpose of the present paper is to point out the bearing which
the investigations already made in this group may have upon the
questions of sexuality in other forms. Some of the problems for
research which the facts observed in the mucors would suggest will
be indicated, and it is hoped that in forms in which an alternation of
generations occurs the distinction between differentiation of sex in
the gametophyte and that in the sporophyte will be more clearly
drawn than has been done previously. The various grades of differ-
entiation in the gametes themselves or in the gametophyte and
sporophyte will not be discussed. The subject for consideration
rather will be the sexual condition in the plant as a whole.

According to the sexual character of their thalli, the species of
the Mucorineae have been divided (2-6) into two main groups,
homothallic and heterothallic—designations which correspond in the
main to the terms hermaphroditic and dioecious respectively. In a_
homothallic species the thalli are all sexually equivalent, while in a
heterothallic species the thalli are of two different kinds, which have
been provisionally designated by the symbols (+) and (—). The
sexual character of the (+) and (—) mycelia remains constant when

* This paper was written while working under a grant as research assistant of
the Carnegie Institution, to whom the writer wishes to express his indebtedness for
the opportunities for research afforded him.

161

162 BOTANICAL GAZETTE [SEPTEMBER

they are grown separately in pure cultures. Thus the opposite
strains of Phycomyces and Mucor Mucedo have been cultivated by
means of sporangiospores to respectively 107 and 106 non-sexual
generations without apparent change in their sexual behavior. This
differentiation into (+) and (—) mycelia, which are capable of
retaining their respective characters apparently for an indefinite num-
ber of vegetative generations, renders the heterothallic mucors as
striking an example of dioecism as is to be found in the plant kingdom.

In those heterothallic species investigated in which a difference
in vegetative growth is apparent, the (+) strain is the more luxuriant.
In higher forms when a difference in size exists between the two
sexes, the female is usually the larger. In such heterothallic forms
the zygote develops entirely from the female thallus, and it would not
seem unnatural that the thallus which supplies nourishment for the
formation of the reproductive bodies should have a greater develop-
ment than the thallus which produces only the comparatively small
male gametes. The zygote of the heterothallic mucors, on the other
hand, is formed by the union of morphologically equal gametes cut
off from similar branches of the sexually opposite thalli. The zygo-
spore is suspended midway between the (+) and (—) thalli which
take equal share in supplying the nutriment for its development.
The difference which sometimes exists in vegetative luxuriance
between the two strains is independent therefore of the demands of

the reproductive bodies, and is to be connected in some way with

the primary sexual differentiation into the two opposite strains.
There are no heterothallic species as yet known in which a con
stant difference between the size of the two gametes has been observed.
Two genera from the homothallic group are heterogamic, and in
these forms the smaller gamete may be assumed to be male and the
larger female. If it were found that a (+) test strain would show
a reaction with the male, while the (—) strain showed a reaction
with the female branch, one would have evidence for considering the
(+) strain female and the (—) strain male. Unfortunately, attemp's
to hybridize test (+) and (—) heterothallic strains with these hetero
gamic forms have been as yet entirely unsuccessful. It is to be
‘hoped that other heterogamic forms may be discovered which will
lend themselves more readily to experiments in hybridization. That

{Se Aa ee ere Oe Ca eis be

1906] BLAKESLEE—DIFFERENTIATION OF SEX 163

as yet it has not been possible to substitute the terms male and female
for (+) and (—), or vice versa, does not in the least detract from the
conclusion, however, that the differentiation is a sexual one.

Forms characterized by gametes equal in size have been commonly
classified as isogamous. The term, it need hardly be pointed out,
can have only a morphological application among the mucors. Sex-
ually the two gametes which unite have diametrically opposite char-
acters. The mutual indifference of two mycelia of the same sex,
and the active sexual reaction between mycelia of opposite sex which
leads to the formation of zygospores when the mycelia are of the same
species, and to the formation of imperfect hybrids when they are of
two different species, indicate that the isogamy is by no means
physiological. The classical researches of BERTHOLD (1) have shown
that among the morphologically equivalent motile gametes of certain
species of Ectocarpus there is a physiological differentiation into
gametes which are attractive and those which are attracted, and a
similar condition is met with among the Conjugatae. In the mucors
the sexes seem to be equally attractive. If in other zygophytic forms
the gametes are ever physiologically equivalent, their union can
scarcely be considered a sexual process in the usual acceptation of
the term.

The physiological differences which exist between the sexually
opposite thalli of heterothallic mucors reaches morphological expres-
sion in those instances in which the (+) in comparison with the (—)
strain is characterized by a greater vegetative luxuriance. Although
the heterothallic forms are morphologically all isogamous, the sexual
differentiation which they exhibit into two distinct races cannot be
considered a lower grade of sexuality than the differentiation shown
in the morphologically unequal gametes of the heterogamic species.
Heterogamic forms are found only in the homothallic group. It
Would seem most reasonable to suppose that the isogamous homo-
thallic forms were the more primitive, and had given rise on the one
hand to heterogamic forms by a differentiation of the individual
gametes, and on the other hand to heterothallic forms by a differen-
tiation of the individual thalli. The partial transformation of the
heterothallic species Phycomyces into a homothallic form which has
been accomplished might, however, suggest the possibility of a deri-

164 BOTANICAL GAZETTE [SEPTEMBER

vation of the homothallic forms from the heterothallic group. There
are seven species known to be homothallic, among which three are
heterogamic, while sixteen are known to be heterothallic. In all prob-
ability the large majority of the species which produce zygospores are
heterothallic, yet the sexual character in but a small proportion of
the mucors has been definitely determined, and it is unknown whether
in this group species may not exist in which sexuality is entirely
lacking. The writer has as yet no theories to offer as to the origin
of sexuality in the group.

The fact that zygospores when germinating in a proper nutrient
medium may give rise directly to a mycelium has led botanists to
discard the idea of an alternation of generations comparable to that
in higher plants, which was formerly seen in the succession from
mycelia bearing sexually formed zygospores to germ tubes producing
non-sexual sporangiospores which complete the cycle by the forma-
tion again of sexual mycelia. The cytological history of the forma-
tion and germination of the zygospores is at present too little known,
and the writer would not care to be responsible for advocating as
yet a too close homology between the conditions seen in the mucors
_ and in the mosses for example, although the branching out of the
germ tube under special conditions to form a mycelium might be
considered of no great significance, since paralleled by the capacity
of the moss sporophyte to give rise directly to a protonema. ie
gross analogy, however, between the germination of the zygote
mucors and that in the mosses is much more obvious than betwee?
the conditions in the mosses and those in the flowering plants oF in
animals (9), and is sufficiently close to justify one in concluding the
mucors in a general comparison of the varying grades of sexual
differentiation in the plant kingdom. In the accompanying dia-
grams and in the ensuing discussion, therefore, the same terminology
will be applied to the mycelium and to the germ tube that has been
found advisable for the gametophyte and sporophyte of forms ’
which it is at present orthodox to speak of an alternation °
generations. :

The terms dioecious, monoecious, and hermaphroditic have been
used to designate varying grades of sexual differentiation, and hav°
been applied to both gametophyte and sporophyte. Dioecism among

1906] BLAKESLEE—DIFFERENTIATION OF SEX 165

the bryophytes has been understood to signify the existence of two
kinds of gametophytes, male and female, and the condition in the
sporophyte has been disregarded; while among the flowering plants
the usage is changed and dioecism has had reference solely to the
sporophyte. An inspection of the accompanying diagrams will show
that a plant which is monoecious as regards its sporophyte may be
either monoecious or dioecious as regards its gametophyte; and on
the other hand a plant dioecious in its gametophyte stage may be
either monoecious or dioecious in its sporophyte stage. The first
case is illustrated by the ferns, which are all dioecious in the sporo-
phyte though having both conditions in the gametophyte; and the
second case is illustrated by the flowering plants, whose sporophytes
are either monoecious or dioecious, but whose gametophytes are
always dioecious. In flowering plants and in ferns, one of the two
generations is characterized by only a single sexual condition, and
attention has accordingly been directed to the other generation in
which both sexual conditions are present. That this inaccuracy in
the terminology has been allowed to stand so long unchallenged is
probably due to the tacit assumption that the condition in the ferns
is typical for all the archegoniates. Up to the present time, however,
the sexual condition in the sporophyte of forms below the ferns has
never, so far as the writer is aware, been a subject of investigation
or even of discussion. |

The terms hermaphroditic, monoecious, and dioecious have estab-
lished themselves in use, and have their place as technical designa-
tions in systematic botany of the flowering plants. As applied to
the cryptogams, they have always been unsatisfactory, since the terms
hermaphroditic and monoecious are used in descriptive botany to
indicate whether the male and female sporophylls are produced in
bisexual or unisexual flowers. In the cryptogams the terms lose
their distinction with the passing out of use of the word flower.
The greater or less local separation of the sexual organs or of the
male and female sporophylls on a single individual is of little signifi-
cance in comparison with the separation of the sexes on two entirely
distinct individuals. Whether in Achlya, for example, the antheridia
arise from the stalk which bears the oogonium as in A. racemosa, or
are produced from separate special branches as in A. prolifera, is a

166 BOTANICAL GAZETTE [SEPTEMBER

detail of somewhat minor importance. The sexual differentiation
on a single mycelium in the latter species may be perhaps a fore-
runner of heterothallism, yet in each species the thallus as a whole
is bisexual.

Rather than attempt to restrict the terms monoecious and dioecious
to either the gametophytic or sporophytic stage, it has seemed best
for the purposes of general discussion in the present article to avoid
the ambiguity of the expressions now in use by applying a separate
set of terms to designate the sexual condition in the gametophyte
and sporophyte respectively. Whether or not the precision thereby
gained will compensate for the disadvantages of adding new words
to an already overburdened vocabulary of technical expressions
must rest with botanists whose interest in the subjects of sexuality
embraces all the groups of the plant kingdom.

Homothallic and heterothallic are terms already explained, which
the writer has used to designate the species of the mucors charac-
terized respectively by thalli sexually all alike, or by thalli sexually
of two different kinds. Homothallic and heterothallic forms, there-
fore, have bisexual and unisexual thalli respectively, and the terms.
accordingly would correspond to the expressions monoecious and
dioecious. Without changing the etymological significance, the mean-
ing of the words homothallic and heterothallic may be appropriately
extended to include a description of the degree of sexual differentia-
tion in the prothallus or gametophyte of the archegoniates and
spermatophytes, as well as in the thallus of the thallophytes.

Homophytic and heterophytic are offered as equivalents in the
sporophyte of the terms monoecious and dioecious. Although the
“plant” in the common acceptation of the word is the sporophyte
in the higher forms, the condition is reversed in the bryophytes.
The words homophytic and heterophytic, therefore, as designations
for the sporophyte are etymologically not above reproach, but will
suffice in lieu of a more cumbersome combination. The terminology
suggested has reference to the sexual differentiation as such. as
accompanying morphological differences are to be considered a5
secondary sexual characters and are not included in the classifica
tion.

It will now be possible to examine the sexual condition in the

PEATE WI

MUCORINEAE | BRYOPHYTES PTERIDOPHYTES PHANEROGAMS
SPORODINIA PHYSCOMITRIUM POLYPODIUM.
fp Slade ce eS
- HomosPoRANGIC -Homosporancic (¢) HomosporANcic
HomosPoric Homosporic
| Homopnytic : Homopuyric Homopnytic
HoMOTHALLIC Be Homoraatsic $8 Homornaric
PHYCOMYCES MARCHANTIA SELAGINELLA ies LILIUM
; HomosPoRANGIC HoMOSPORANGIC HETEROSPORANGIC @) HETEROSPORANGIC
: HETEROSPORIC HETEROSPORIC HETEROSPORIC Wie HETEROSPORIC
me. Homopnytic
OPHYTIC
HoMopuHytic HoMopuHytic
\ |
Sods | Be SSX
HETEROTHALLIC # Hererornariic aS) PS $ Hererornarzic 3 RB 394.9 HErERoTHArric
Z Bs) j
MUCOR MUCEDO | | | POPULUS ;
HETEROSPORANGIC | -HETEROSPORANGIC Ae
_ HETEROSPORIC | (3) HETEROSPORIC (9)
_ HETEROpPHYTIC | 3b HETEROPHYTIC , Q

1906] BLAKESLEE—DIFFERENTIATION OF SEX 167

groups represented in the accompanying diagrams. In all the figures
the gametophyte has been shaded with parallel lines, the antheridia
and zygotes with cross-hatching; while the sporophyte and the spor-
angia have been left unshaded. The drawings are entirely diagram-
matic, and no attempt has been made, therefore, to preserve the
relative proportions of the parts figured. As has been already
explained, the Mucorineae have been included in this scheme for the
purpose of comparison, and the germ tube has been thus homologized
with the sporophyte. The mucors then as represented in the first
column in the diagram are the only group outlined in which all the
three main types of sexual differentiation are as yet known.

In Sporodinia grandis, which may be taken as representative of
the homothallic group, the mycelium (gametophyte), the germ tube
(sporophyte), and the germ sporangia are all alike bisexual. The
two opposed gametes, and perhaps the branches from which they
are cut off, may not unreasonably be considered unisexual and of
Opposite sex. It has not been found possible as yet, however, to
confirm this assumption experimentally. In the terminology adopted
the species is to be considered homothallic, homophytic, homosporic,
and homosporangic. The same condition is found in the “monoe-
cious”? mosses represented by Physcomitrium pyriforme, and in the
homosporous ferns represented by Polypodium. The sporangium
of the latter is represented as a side branch, since in the ferns, as
also in the flowering plants, the sporangia are not simple terminations
of unbranched sporophytes of limited growth, as in the bryophytes,
but are borne on the sporophylls of a sporophyte more or less highly
developed.

If the sexual character of the thallus be preserved, the spores and
the sporophyte producing them must be also bisexual. There can

only one type therefore of homothallic forms. Of heterothallic
forms, on the contrary, two types are possible—namely, those with
bisexual sporophytes, i, e., homophytic, and those with unisexual
Sporophytes, 7. ¢., heterophytic. These two types are represented
by Phycomyces nitens and Mucor Mucedo respectively.

In the heterothallic species Phycomyces it will be convenient for
the purposes of the present paper to neglect those instances in
which the germination follows the Mucor Mucedo type, as well as the

168 BOTANICAL GAZETTE [SEPTEMBER

occasional formation of homothallic spores in the germ sporangia,
and to consider as typical the condition shown in the diagram. For .
a more detailed account of the zygospore germination in Phycomyces,
as well as for the characters of the homothallic form into which this
heterothallic species has been transformed, one must refer to the
paper on zygospore germinations already cited. In the type, per-
haps somewhat arbitrarily selected for discussion, the germinations
are mixed—both male and female spores being produced in a single
germ sporangium. The mycelia in this species are unisexual, the
zygospores and germ tubes are bisexual, and the spores in the germ
sporangia are unisexual, If the germ tube be forced to form a
mycelium without the intervention of sporangiospores, a bisexual,
7. e., homothallic, mycelium results, which may produce typical
homothallic zygospores. Phycomyces as discussed, therefore, is
heterothallic, homophytic, heterosporic, and homosporangic.

In the bryophytes, Marchantia polymorpha is the only form which
has been investigated in regard to the sexual condition of its sporo-
phyte (cf. p. 170). Its gametophyte shows a differentiation into male
and female thalli, and the germination of the zygote produces a
sporophyte which bears a sporangium containing both male and
female spores. Marchantia, therefore, like Phycomyces is hetero-
thallic, homophytic, heterosporic, and homosporangic.

Selaginella, as a representative of the heterosporous ferns, follows
in the main the Phycomyces type. It differs from Phycomyces and
Marchantia, however, in that it is heterosporangic—the male and
female spores being separated in microsporangia and macrosporangia.
The spores themselves, moreover, are morphologically of two kinds,
the female or macrospores being conspicuously larger than the male
or microspores. This morphological differentiation of the spores
and sporangia is known only in the heterosporous ferns and in the
flowering plants, and is accompanied by a reduction in the size of
the gametophyte. Among the homosporous ferns, prothalli are often
found with only archegonia or antheridia, and investigators have
been able to suppress the formation of one or the other in certain
species where archegonia and antheridia occur normally side by side
on the same prothallus, The writer is aware, however, of no form

1906] BLAKESLEE—DIFFERENTIATION OF SEX 169

among the homosporous ferns which investigators have shown to
be strictly heterothallic.

In the monoecious and hermaphroditic phanerogams, illustrated
by Lilium, the condition is essentially the same as in Selaginella,
with a differentiation into macrospores and microspores, and like
the latter species the type may be described as heterothallic, homo-
phytic, heterosporic, and heterosporangic.

The homophytic division of the heterothallic group illustrated by
Phycomyces is the only one of the three types et has representatives
in all the orders outlined.

Mucor Mucedo represents the heterophytic division of the hetero-
thallic group. In contrast to Phycomyces, the zygospores of this
heterothallic species furnish pure germinations, but the spores are
unisexual; and while the germ tube and the sporangiospores produced
from one zygospore are male, those produced from another may be
female. There are, therefore, two different kinds of germ tubes,
of sporangiospores, and of sporangia, as well as two different kinds
of mycelia. These elements in this species show no more recog-
nizable morphological differences than its mycelia, although the
sexual differentiation seems to be as marked as in forms in which
such a morphological differentiation exists throughout the whole
plant. Mucor Mucedo is heterothallic, heterophytic, heterosporic,
and heterosporangic.

Since Marchantia is the only heterothallic form among the bryo-
phytes the sexual character of whose sporophyte has been investi-
gated, it is as yet unknown whether any forms of the mosses and
liverworts exist corresponding to the Mucor Mucedo type.

No heterophytic forms are known at present among the hetero-
thallic pteridophytes, and it will be impossible to say whether they ever
existed in geologic times. The non-appearance of one reproductive
form on a given sporophyte cannot be taken at once as proof that the
species is heterophytic. It not infrequently happens, for example, that
one finds only microsporangia on a single individual of Selaginella.
Such instances may be compared to the suppression of the organs
of one sex on the prothalli of homothallic ferns, and may equally be
explained by assuming that the conditions necessary for the forma-
tion of the two reproductive bodies do not always coincide.

170 BOTANICAL GAZETTE [SEPTEMBER

The “dioecious” phanerogams, represented by the heterophytic
form Populus, follow closely the Mucor Mucedo type. They differ
from Mucor Mucedo in that the sexual differentiation has reached
a morphological expression, and the sex of the thalli, spores, and
sporangia is at once distinguishable. In general the male and female
sporophytes are alike in appearance, but in the sporophytes of some
forms the sexes are easily distinguished. Perhaps the best known
example among the common trees is the Lombardy poplar (Populus
pyramidalis), which in male specimens has been widely cultivated
for the sake of its pyramidal form. The female trees have a spread-
ing habit of growth and are seldom to be found in cultivation.

In the diagram three squares are left blank. In the flowering
plants heterothallism has become fixed and no forms of the Sporo-
dinia type exist. There is no reason apparent why heterophytic
forms should not occur among the heterothallic pteridophytes. The
fact remains that all the existing heterothallic species are homophytc.
The blank squares in the phanerogams and pteridophytes must there-
fore remain unfilled, Little is known about the sexual differentiation
in the bryophytes, and it must rest with future research, therefore,
to determine whether or not they possess heterophytic representatives
in the heterothallic group.

In light of the conditions found in the Mucorineae, the hetero-
thallic bryophytes, as already pointed out by the writer (/. ¢., P- 25),
offer a most interesting field for investigation. Accordingly nee
tion was directed to the heterothallic form Marchantia polymorpha,
which, according to the unpublished observations of NOLL as reporte
by ScHULTZE (17), retains the unisexual character of the individual
thalli when propagated vegetatively by gemmae.

During the last November, Marchantia was found in fruit and
sowings were made from individual sporangia, and the young plants
resulting from their germination were isolated and transplanted 1
such a manner that at fructification it would be possible to determine
the sex of the individual spores from which they were derived. While
the present paper was largely in manuscript, the writer learned of
unpublished observations made by Nott on this same species. Pro-
fessor Nott, to whom the writer is greatly indebted for the inform
tion communicated, has cultivated Marchantia by means of gemmat

1906] BLAKESLEE—DIFFERENTIATION OF SEX 171

for over thirty generations of both male and female strains, without
having been able to change the sexual character of the thalli by sub-
jecting them to varying conditions of growth. The form is therefore
strictly heterothallic. Moreover, in a single instance a sporangium
was made to discharge its spores on a pot of earth, and male and
female fructifications were obtained from the mixed growth of thalli
resulting from their germination. Marchantia is therefore homo-
phytic, and it now becomes possible to fill out in the diagram one of
the two squares which in the bryophytes had been left blank pending
the fructification of the young thalli which the writer had obtained
from isolated spore germinations.?

In Phycomyces, with which Marchantia is to be compared, there
seems to be no definite relation between the number of male to female
spores formed in a germ sporangium, and it may even happen that
all the spores are of the same sex. Moreover, it is not infrequently
the case that in a small per cent. of the spores in a germ sporangium
the segregation into male and female has not been completed.
These bisexual spores produce homothallic mycelia. Cultures from
individual spores will be necessary to determine for Marchantia
the proportion of male to female spores in a single sporangium, and
to ascertain if, in addition to the normally unisexual spores, bisexual
spores are ever formed, as is the case in Phycomyces.

The bisexual germ tube of Phycomyces may be cut and forced to
branch out to a homothallic mycelium. The observations of Nott
and of the writer have shown Marchantia to be homophytic. Its
sporophyte as a whole, therefore, must be bisexual, and every cell
formed before-the determination of the sex of the spores, if brought
to develop into a new plant, should theoretically produce homothallic
individuals. PRrincsHErm (16), STAHL (18), and CoRRENS (10),
among others, have obtained protonemata from the sporophytes of
mosses. -No one, however, seems to have succeeded in obtaining
Tegeneration from the sporophyte of liverworts. The writer has
experimented with mature sporophytes of Fegatella and with sporo-
phytes of Marchantia of various ages, but has been unable to secure
any growth from them.

? While the present paper is in press, 12 thalli have so far produced seater
out of a total of rx '3 which were obtained from as many spo res from a single spo
gium. Of these nine are male and three are female.

172 BOTANICAL GAZETTE [SEPTEMBER

In the investigation of the typical germinations of Phycomyces,
it has been shown that the determination of sex does not occur in
the zygote, but that an interval in the form of a germ tube is inter-
polated between the zygote and the germ sporangium where the
segregation of sex finally occurs. The essential difference between
Phycomyces and Marchantia lies in the fact that in the former the
interval is a single-celled multinucleate structure arising from a
multinucleate zygospore, while in the latter the interval is made up of
many uninucleate cells arising from a uninucleate oospore. In Mar-
chantia-the segregation of sex undoubtedly takes place at some point
in the maturation of the sporangium. If the archesporium and the
spore mother cells prove capable of germinating, and it be possible
in the thalli which result to recognize the presence of both sexes
when the plants are homothallic, one may be in a position to deter-
mine the exact point where the segregation of sex occurs and to
discover what relation if any the segregation may have to the reduc-
tion division or to other nuclear phenomena.

The predominance of organs of a single sex on the prothallus of
the ferns due to conditions of growth and the similar phenomenon
in the sporophyte of Selaginella may lead to the non-appearance of
the other sex. Such a suppression of sex, however, is not to YF
confused with sex determination. By cultivating fern prothalli
under unfavorable conditions of nutriment, PRANTL (15) Was able
to confine the production of sexual organs to antheridia. The
archegonia demand a prothallus furnished with meristematic tissue,
and consequently on a poorly nourished prothallus which has de-
veloped no meristem only antheridia can be formed. If prothalli
which are producing exclusively antheridia be removed from a culture
medium containing no available nitrogen, to a medium in which
available nitrogen is present in sufficient amount, meristematic
tissue is developed upon which archegonia are formed. KLEBS
(12), moreover, has shown that by reducing the amount of light to
which they are exposed prothalli may be brought to a prolonged
vegetative growth, and thus the formation of both antheridia and
archegonia may be suppressed. Professor KLEBS has informe
the writer that when the amount of light is increased to a certal”
extent, antheridia alone are produced from these sterile prothalli,

1906] BLAKESLEE—DIFFERENTIATION OF SEX 173

but that to obtain archegonia, they must be exposed to a still greater
illumination. BucHTIEN (7) has shown that in Equisetum external
conditions have a similar influence upon the apparent sex of the
prothalli.

As yet attempts to influence arbitrarily the sex in unisexual plants
have entirely failed. Even though it remain impossible to change
the sex in the thalli of Marchantia, it may be found that, by experi-
menting on the sporophyte where we must assume the sex is unsegre-
gated, one may-be in a position to bring about the exclusive pro-
duction of either male or female spores in a given sporangium. Such
a result if accomplished would be analogous to the suppression of
one set of sexual organs on the prothalli of ferns.

The behavior of the gametophyte of homothallic ferns and that
of the sporophyte of such heterophytic flowering plants as Melan-
drium album (19) shows that, abnormally in certain forms and nor-
mally in others, only one sex may make its appearance. The con-
clusion suggested by an assemblage of facts, especially from the
animal kingdom, is generally accepted that in so-called unisexual
forms one sex is dominant and finds expression in the formation of
gametes or spores of the given sex, while the opposite sex exists in
a latent condition. However probable such a conclusion may appear
for the majority of forms investigated, it must be admitted as at
least a possibility that in certain plants or in certain stages a single
Sex May exist in a pure condition. The fact that besides the occa-
sional production of unisexual germ tubes the zygote of Phycomyces
gives rise typically to germ tubes in which the differentiation of sex
has not taken place is proof neither for nor against the purity of the
male and female thalli, and suggests that the not infrequent occur-
rence among heterophytic flowering plants of individuals with male
and female flowers is as much an indication that both pure and
mixed conditions may exist in the sporophyte of these plants as a
Proof that in heterophytic plants the opposite sex always exists in
a latent condition. The germinations of the zygotes of Phycomyces
and Marchantia suggest the possibility that the sex may be pure in
the gametophyte while mixed in the sporophyte. The observations
On unisexual plants, however, have been as yet confined almost
entirely to the sporophytic stage, and little is known as to how strict

174 BOTANICAL GAZETTE [SEPTEMBER

the differentiation of sex actually is in plants in the gametophytic
stage.

Unless the gametes contain both sexes, parthenogenesis in homo-
thallic forms should give rise to unisexual individuals—the male
gamete to male and the female gamete to female individuals. So
far as the writer is aware, no investigations have been undertaken
with a view to confirm this assumption experimentally. Attempts
made by the writer to determine the sexual character in the gametes
of homothallic mucors by means of their germination before or after
their transformation to azygospores have not as yet been successful.
In the higher plants, parthenogenesis in the sense of the develop-
ment of an individual from a sperm or egg cell with the reduced
number of chromosomes is, so far as the writer is aware, not definitely
known to occur. The sex in the apogamous seeds of Taraxacum
for example, however, must contain male characters if the plants
produced from them develop stamens, as seems regularly to be the
case.

What the essential difference between sex actually is, is as yet
beyond conjecture, and the significance of sex in organic develop-
ment is at present a subject of conflicting discussion. It is to be
hoped that a further study, especially of lower forms, where the
gametes are more closely connected with the vegetative portions
and the zygotes formed by their union more accessible to manipu-
lation, may lead to a better understanding of some of the funda-
mental problems of sexuality. The present brief article is no place
for any detailed discussion of sexuality in the various groups of
plants. For a short general presentation of the subject, the
reader may refer to the recent work of KisTER (13) and to the litera-
ture therein cited. It seems not out of place, however, to S4Y .
few words in regard to the thallic differentiation in the lower crypto
gams, where the subject has received little attention. :

Unisexual and bisexual forms occur throughout the plant king-
dom, and are often to be found in the same genera. This sex
differentiation seems to have no relation to the stage of phylogenetic
development.. Thus while in higher animals the unisexual con®
tion predominates, in higher plants the monoecious, ?. ¢- homophyt;
condition is the more common. Again, the majority of the ferns

OP ee Re Te,

1906] BLAKESLEY—DIFFERENTIATION OF SEX 175

are homothallic, while the majority of the mucors investigated are
heterothallic. Both conditions, therefore, may be expected a priori
in any group under investigation, whatever may be its phylogenetic
rank.

In groups in which sexuality is present, in both fungi and algae,
there are many forms for which the sexual spores have been but
rarely found or are entirely unknown. The absence of-sexual repro-
duction may be due (1) to constitutional sterility, (2) to conditions
of growth unfavorable to the production of sexual organs, or (3) to
the fact that the form is heterothallic and thalli of both sexes have
not been found together. In the last case the apparent sterility
would not be due to a lack but rather to an excess of sexuality which
separates the male and female individuals. Even in heterothallic
species, neutral races have been found to exist, and the conditions
within which sexual reproduction is possible are frequently very
limited.

A morphological investigation may suffice to show that the male
and female organs are borne on the same thallus, and the form in
question can then be at once classified as homothallic. A hetero-
thallic condition, on the other hand, can never be recognized by a
morphological investigation alone. The appearance of but one set
of sexual Organs on an individual form studied under the microscope
may be due either to dichogamy or to suppression of the other sex
brought about by conditions of growth, as well as to a unisexual
character of the thalli. Carefully conducted cultures are therefore
essential to a determination of the sexual character of forms inves-
tigated. A few examples may be briefly given to illustrate the neces-
sity of employing the cultural method in a study of even well-known
orms. Many other examples equally as appropriate will suggest
themselves to the reader.

In the mosses the leafy shoots arise from an inconspicuous pro-
tonema, and if certain shoots bear only antheridia and others only
archegonia, a cursory investigation would lead one to consider the
forms heterothallic, especially if the antheridial and archegonial
“plants” differ in appearance. Funaria hygrometrica, for example,
'S classified as monoecious by LIMPRICHT (14) and CorRRENS (10),
yet CAMPBELL (8, p. 187) says “‘Funaria is strictly dioecious.” The

176 BOTANICAL GAZETTE [SEPTEMBER

term here is perhaps used in reference to the constant separation of
the sexual organs on different shoots without regard to their ultimate
connection on the protonema; yet the latter is as an essential part
of the plant as the leafy axis, and if the species is in fact homothallic
it is not to be called dioecious. Such forms as Funaria offer an
interesting field for regeneration experiments to determine if pro-
tonemata developed from antheridial and archegonial shoots differ
at all in sexual character.

Among the algae, Spirogyra, to mention a simple example, is a
familiar genus in which homothallic species are known to occur,
and in which heterothallism is strongly to be suspected for certain
species from a mere morphological investigation. In fig. 7, which is
taken from STRASBURGER’S textbook, is represented Spirogyra longata.
It seems in this type to be 4
matter of indifference whether
the two conjugating cells come
from the same or from different

filaments are bisexual and the
species is therefore homothallic.
In Debarya, represented in fig: 2»
the zygospores are formed, as 10
the heterothallic mucors, midway
between the two thalli, between
which no differences are apparent:
In the most common form °
conjugation, however, which is represented in fig. 3, one filament
seems to be receptive, since it contains all the zygotes formed be-
tween two conjugating filaments and has therefore been considered
female. Though rather improbable, it is yet imaginable that a fila-
ment which acts as female toward one thread might function %*
male toward another. Theoretically it would not be a difficult task
to determine by cultivation the sexual character of any form je

producing zygospores.

Fic. 1 Fic, 2 Fic. 3
Spirogyra Debarya Spirogyra

The Saprolegniaceae form sexually one of the most interesting -

groups among the fungi. In Achlya racemosa the i
branches are borne from the stalk of the oogonium, in A. polya

threads. Obviously here the

1906] BLAKESLEL—DIFFERENTIATION OF SEX 297

they arise fom differentiated branches which are only distantly con-
nected with the hyphae which bear the oogonia, and in Saprolegnia
dioica and S. anisospora we have forms which have been described
as dioecious. Cultural investigation alone can determine whether
these latter forms are in fact heterothallic. It is perhaps significant
that in this group forms have been found which have remained
sterile under cultivation (cj. HoRN, 11. p. 232). It is not improbable
that they may represent unmated strains of heterothallic species.

Of especial interest will be an investigation for the possible occur-
rence of two sexual races in groups such as the desmids, the flagel-
lates, and the infusoria, where the whole vegetative organism func-
tions directly as the gamete.

Among the cryptogams, with the exception of the mucors and Mar-
chantia, the sexual relations of the offspring from a single zygote in
heterothallic forms, the zygotes of which give rise to more than a
single individual, have never been investigated. The condition in
the bryophytes has been already discussed under Marchantia. In
the thallophytes writers see an alternation of generations variously
expressed or suggested in the interpolation of carpospores between
the fertilized zygote and the young plant. Whether in the hetero-
thallic oedogoniums, to mention but a single example, the four
Carpozoospores formed at the germination of the oospore are always
all of the same sex, like the germ spores in Mucor Mucedo, or may
be some male and some female, like the germ spores in Phycomyces,
can be decided only by an investigation of the individual thalli
which they produce. If species in the Saprolegniaceae and Per-
Onosporeaceae are found to be_heterothallic, these forms will
likewise furnish a fruitful field for investigation.

The discussion in the foregoing pages is based for the most part
upon investigations done or already in progress in the Botanical
Institute in Halle. The writer wishes to express his grateful appre-
ciation to Professor Kies for the facilities of the laboratory and
for his unfailing sympathy in the researches undertaken.

Paris, April, 1906.

N

a

baal

©

BOTANICAL GAZETTE [SEPTEMBER

LITERATURE CITED

1. BERTHOLD, G., Die geschlechtl. Fortpflanzung der eigentlichen Phaeosporeen.

Mitt. Zool. Stat..Neapel 2: 401-412. 1881.

. Brakester, A. F., Zygospore formation a sexual process. Science N. S.

19:864-866. 1904.

Sexual reproduction in the Mucorineae. Proc. Am. Acad. 40:205~

319. pls. 1-4. 1904.

Two conidia-bearing fungi, Cunninghamella and Thamnocephalis.

Bot. Gazette 40:161-170. pl. 6. 1905.

Zygospore aes in the Mucorineae. Annales Mycologici

4:1-28. pl.r.

Zygospores mee sexual strains in the common bread mould, Rhizopus

nigricans. Science N. S. 24: 118-12

. Bucutien, O., Saiki dachickitn des Prothallium yon Equisetum.

Bibliotheca Hater inn 8: 18

. CampBett, D. H., Mosses and ens. 18

. CHAMBERLAIN, C. J., Alternation of Gncralions in animals from a botanical

standpoint. Bot.Gazette 39:137-144. 1905.

. CorRENS, C. ha phates iiber die Vermehrung der Laubmoose. PP:

472. fig. 187. Jena. 1899.

. Horn, L. ces teeertielie Entwickelungsinderungen bei Achlya polyandra.

Anoales Mycologici 2: 208-241. 1904

. Kress, G., Ueber den Einfuss des lchtes auf die Fortpflanzung der

Gewichse. Biol. Centralbl. 13:641-656. 1893.

. Kiser, E., Vermehrung und Sexualitit bei den Pflanzen. Aus Natut

Geisteswelt 112:1-114. fig. 38. Leipzig, 1906.

. Liwpricut, K. G., Die Laubmoose. Rabenhorst’s. Kryptogamen-Flora
2

. Pranti, K., Beobachtungen iiber die Ernahrung der Ferapenthaly und
die Varttelouy der Sexualorgane. Bot.-Zeit. 14:nos. 46 and 47. 1°
. PrincsHerm, N., Ueber Sprossung der Moosfriichte. Jahrb. Wiss. Bot.
pe Sh oe 1878.

: beaters. O., Zur Frage von den geschlechtsbildenden Ursachen. Archiv.
Mikr. Aiet Entwickel. 63:197-257. 1903

. STAHL, E., Ueber kiinstlich hervorgerufene Aiceeisaneh an. ae
Soaipenhies der Laubmoose. Bot. Zeit. 34: 689-695. 1579- ss
- STRASBURGER, E., Versuche mit didcischen Pflanzen. Biol. Centralbl. 29:
nos. 20-24. 1900.

eS

A STUDY OF THE VEGETATION OF THE MESA REGION
EAST OF PIKE’S PEAK: THE BOUTELOUA FOR-
MATION.

Il. DEVELOPMENT OF THE FORMATION.
H. L. SHANTZ.
(WITH SIX FIGURES)
IN an earlier paper™ the writer has discussed the structure of the

Bouteloua formation, and to this publication the reader is referred

for general introductory matter. Space will not permit the inclusion

_ here of lists of species in the formations of minor importance, which

_. have to do with the development of this formation. The foothill

age ee Aen tee Nt pe ee ae Gee ee

thicket formation, the plains ruderal formation, and the plains bank
formation are each made up of many species. Only the facies and a
few of the more important principal species can be mentioned.
Invasion by formations.
FOOTHILL THICKET FORMATION.

This formation extends along the eastern base of the mountains
and down along the ridges and gullies far out on the plains. It
forms a distinct zone at the base of the mountains (fig. 8) and here
occurs in its best developed form. In most places under natural
conditions there seems to be an ecotone, a place of equal aggressive-
hess, between this formation and the Bouteloua formation.

Facies: Cercocarpus parvifolius H. & A., Rhus trilobata Nutt., Quercus
nhovo-mexicana (DC.) Rydb., Q. utahensis (DC.) Rydb., Q. Gambellii Nutt.

Principat Spectes: Rubus deliciosus James, Holodiscus dumosus (Nutt.)
Heller, Ribes cereum Dougl., R. leptanthum Gray, R. pumilum Nutt.

In addition to those named there are about one hundred principal and second-
ary species.

This formation and the Bouteloua formation seldom mix, because
where the shrubs grow the facies of the grass formation cannot exist.
Nearer the mountains and along the hillsides they alternate sharply.

While the climatic and soil conditions are identical, the differ-

* Bor. Gazette 42:16-47. 1906. :

179} (Botanical Gazette, vol. 42

180 BOTANICAL GAZETTE [SEPTEMBER

ence in cover causes great difference in physical factors. Simulta-

neous physical factor readings show very clearly these differences.
The following is a typical set:

Aug. 3, 1904, 10:45 a. m.

TEMPERATURE REL. HUMIDITY :
Biss ie ____| WATER
Licut poarch
~ Soil Plant a m cm rr TEN
S. - od cm ™ oy = I
oil surface | surface gs
Ope ki 6s 24° Bote| aa? 29°6 | 2874 | 40% 32°70 | 3 ¥
Thicket (Quercus)| 180s 18° 30° | 28°2 | 27°2 | 26°8 | 42% | 39% | 9-3A

: ee

So es ; A . -hya and
Fic. 8.—Zonation at Palmer Park; frontal zone of Bouteloua oligostachya 0”
ee : - hase: OF
Artemisia frigida; zone near base of the bluff Andropogon furcatus; he base
the bluff the foothill thicket (Quercus); the bluff showing pine formation (P. s¢
lorum).

rope

apart.

These conditions existed on the same exposures and 6™
Arle-

The open quadrat was dominated by Bouteloua oli gostachya an
mista frigida; while the shaded quadrat contained Quercus utahe?

Sande

1515,

1906] SHANTZ—VEGETATION OF THE MESA 181

Coleosanthus umbellatus, Oryzopsis micrantha, Elymus condensatus,
Filix jragilis, and Bryum argenteum. The thicket was rather open,
as may be seen at once by the light readings, the ratio of which is
3y: This ratio often becomes ,';, but is usually less for the greater
part of the formation.

Along the ridges north and east of Colorado Springs there is certain
evidence that the thicket formation is slowly pushing its way out
into the grass formation. Of the shrubs Cercocarpus parvijolius
seems best adapted for this invasion, and it is several miles in advance
of any of the other dominant species (jig. g). Nearer the mountains

a ee RE ae ele ae tele

_ Fic. 9-—Cercocarpus parvifolius invading the Bouteloua formation; pine forma-
tion on the horizon

evidence is also found of the invasion of the grass formation by the
thicket formation. This invasion, however, is not rapid. As soon
as the young shrub is established or has grown to sufficient size to
Produce shade, the grass formation gives way rapidly to species

182 BOTANICAL GAZETTE [SEPTEMBER

of the thicket formation. Among the first species to appear in the
shade of these advancing shrubs are Calochortus Gunnisonit, Mer-
tensia linearis, and Stipa neo-mexicana. Later, when the habitat
has been rendered less xerophytic and when the other facies have
entered, Coleosanthus umbellatus, Oryzopsis micrantha, Elymus con-
densatus, Selaginella rupestris Fendleri, Filix fragilis, and a number
of other species appear. .

- Under perfectly natural conditions and without the intervention
of herbivora, the thicket would undoubtedly replace the greater part
of the grass near the mountains, but, as is seen later, the thicket is
slowly giving way and the grass formation is advancing.

PLAINS RUDERAL FORMATION.

Factes: Stipa Vaseyi Scribn., Puccinia Stipae Arth., Boebera pappos@
(Vent.) Rydb., Helianthus petiolaris Nutt., Puccinia Helianthi Schw., Thelesperma
intermedium Rydb., Verbena bracteosa Michx., Amaranthus blitoides S. Wats.

PRINCIPAL SPECIES: Salvia lanceolata Willd., Lappula occidentalis (Wats.)
Greene, Polygonum aviculare L., Erysiphe Polygoni DC., Munroa squarrosa
(Nutt.) Torr., Salsola Tragus L., Euphorbia glyptosperma Engelm.., Malvastrum
coccineum (Pursh) Gray, Puccinia Malvastri Pk., Vicia americana, Aecidium
porosum Pk., Solanum rostratum Dunal, Helianthus annuus L., Cleome serrulata
Pursh, Schedonnardus paniculatus (Nutt.) Trelease, Atriplex argentea Nutt.,
Senecio spartioides Torr. & Gray, Verbesina encelioides (Cav.) Gray; Helianthus
petiolaris Nutt., Puccinia Helianthi Schw., Picradeniopsis oppositifolia (Nutt.)
Rydb. :

The secondary species of this formation are very numerous.

The physical factors of this formation are practically the same
as those given for the Bouteloua formation. The conditions of
water content are such that the most common ruderals, easter and
European species, cannot thrive to the best advantage. Many
native plants behave as ruderals and this name is applied to the
formation. This formation represents many different stages in be
succession which will result ultimately in the grass formation, and 1s
always invaded by the plants of the grass formation. Only @ 7°
of the ruderal species succeed in the grass formation. The most
important of these is Boebera papposa, occurring everywhere through
out the formation and sometimes very abundant. It is much better
developed in a ruderal position and is regarded as a part of the
ruderal formation. Stipa Vaseyi, another native plant, succeeds

best in ruderal positions, but is often found as part of the formation-

1906] SHANTZ—VEGETATION OF THE MESA 183

The species of the ruderal formation are almost entirely native
plants which readily invade any area from which the vegetative
covering has been removed. Of the true ruderals, Salsola Tragus
pushes its way into the formation proper. Here it occurs as dwarfed
plants which seldom branch, and which die during the aestival period.
Leptilon canadense, which occurs only here and there in the ruderal
formation, also occurs throughout the grass formation. The plants
are usually reduced to 1o™ in height.

PLAINS BANK FORMATION.

Whenever a ditch is made through the grass or other formations,
or where the grass formation is irrigated, the bank formation comes
in. It matters not what kind of soil, the presence of an abundance
of water enables this formation to succeed. © This, however, is not
true invasion, and comes about only as a result of changed condi-
tions which make the existence of the grass formation impossible.
Good examples of the coming in of the bank formation may be found
in irrigated meadows and in small areas where irrigation ditches or
reservoirs have leaked. :

A study of this formation is of the greatest interest, for it is along
this formation that the eastern species find their way into the region.
The reason is obvious, for here they find suitable conditions of water
supply. As a result, it is here that the vegetation is made up of the
most widely distributed species.

The mountain species find in this formation the cool temperature
that enables them to exist away from their natural habitats. These
species pass down along the brook banks, while the eastern species
Pass up along these same banks. The result is a varied flora.

The radical difference in water content between this formation
and the Bouteloua formation does not permit of direct invasion.
The following species, however, may occur in either formation:
Erigeron flagellaris, A gropyron occidentale, Helianthus annuus, HH.
petiolaris. ;

The facies of the bank formation varies greatly with the age of
the formation. In the ultimate stage they are as follows:

Populus deltoides Marsh., P. angustifolia James, P. acuminata Rydb.,
Salix spp., Prunus melanocarpa (A. Nels.) Rydb., P. americana Marsh., Rosa Sayi

184 BOTANICAL GAZETTE [SEPTEMBER

Schwein., Ribes aureum Pursh, Clematis ligusticifolia Nutt., Symphoricarpos
occidentalis Hook., Rhus trilobata Nutt. :

In an earlier stage this formation is found best developed in
the irrigated meadows where Poa pratensis L., Eragrostis alba L.,
Juncus balticus Willd., Heleocharis palustris (L.) R. & S., and
Medicago sativa L. may rank as facies.

~* ~ . “ ‘ ; 4st the Routelou4
Fig. 10.—Floor of the pine formation (P. scopulorum) covered with the Boute!

formation (B. oligostachya, Koeleria cristata, and Artemisia canadensis).

Xanthium commune and Melilotus alba are among the very a
plants to enter on a newly formed ditch bank. In this formation
are found many of the common species which occur in mesophyti¢
situations in the eastern part of the United States.

PINE FORMATIONS.

. 2 - formations
As CLEMENTS? has pointed out, there are two pine format |
ang

near the base of the mountain range, the “foothill woodland

2 Univ. Neb. Studies 4: no. 4. 1904.

1906} SHANTZ—VEGETATION OF THE MESA 185

the ‘“‘pine.”” The first has as facies Pinus edulis Engelm. and
Juniperus monosperma (Engelm.) Sarg.; and. as principal species,
Stipa Scribneri Vasey. The second has as facies Pinus scopulorum
(Engelm.) Lem. and P. flex:lis James.; and as principal species,
Arctostaphylos Uva-ursi (L.) Spreng.

Fic. 11.—Pinus scopulorum invading the Bouteloua formation.

In the zone at the base of the mountains lies the foothill woodland
formation, while just above is the pine formation. Each of these
‘ormations is invading the Bouteloua formation, and the one which
lies higher on the mountains, the pine formation, is the more successful.

A consocies of this formation dominated by Pinus scopulorum has
pushed its way eastward far into Nebraska’ and carries with it many
Of the principal and secondary species. P. flexilis drops out before
the foothills are reached. Near Eastonville, Colo., this formation

* Pound and Crements, Phytogeegraphy of Nebraska, 2d ed., Lincoln, Neb.,
1900, p. 336.

186 BOTANICAL GAZETTE [SEPTEMBER

may be seen meeting the Boutcloua formation. All along this ridge
the thicket formation has dropped out and the pines advance alone.
The forest is not dense, and while many of the principal and secondary
species are found on its floor, plants are also found which belong to
the grass formation and which are able to survive in this location.
In fact, the grass formation is found here in places dominating the
floor of the pine formation—a true mixing of the formations (fig. 10).
This mixing may be due to a certain extent to the entrance of the
dominant species of the grass formation, but it is more likely to be
the result of the gradual advance of the pines into the grass forma-
tion. This is shown very clearly in places where the young pines
are several meters in advance of the older trees (fig. 11). This inva-
sion may be observed along the ridge leading eastward from Palmer
Lake and on which is found the so-called “black forest.” Here
the pines and the grasses mix and there are no shrubs present (jig- 1 0).
The principal species, Arctostaphylos Uva-ursi, is also pushing out
into the grass formation. A short distance west of Pring, Colo.,
this pine formation may be seen rapidly advancing along an old
roadbed.

An entirely different condition may be observed eleven miles
east of Colorado Springs. Here the pine formation is also advancing,
but it is accompanied or rather preceded by the thicket formation.
The advance of these two formations is favored by the cutting back
of the gullies, forming steep hillsides, which offer the most favorable
conditions for the growth of these two invading formations.

In many places the thicket, pine, and grass formations are found
to meet and mix equally, the grasses forming the floor between the
shrubs, and the pine scattered throughout. These three important
formations are not only found meeting here on equal terms, but 4
remnant of an older formation, or at least one which gives evidence
of greater age, is also found. This is the foothill woodland. Jun
perus monosperma is scattered here and there and isolated trees of
this species are often found which seem to be very old. _ Still stronger
evidence is found in the fact that here, many miles removed rom
its fellows, is a very large and apparently very old Pinus edulls.
Erosion has removed the soil from the base of the tree, exposing "
roots, and it is certainly much older than any of the other trees

|

1906] SHANTZ—VEGETATION OF THE MESA 187

in this region. It is the only tree which supports a rich lichen
flora.

Four important formations are found meeting and mixing here:
the oldest, the foothill woodland, which has almost disappeared;
the pine formation, which is slowly advancing; the thicket forma-
tion, which is also gradually advancing; and the grass formation,
which gives way as the others advance. The thicket formation at
this point entirely lacks the oaks, which fact is probably due to
grazing.

In another part of the grass formation there is evidence of a slight
advance of the foothill woodland. Young trees of Juniperus mono-
sperma have established themselves in a few places on the mesa.
In other places Stipa Scribneri is entering the plains region along
with the thicket formation. The preponderance of evidence, how-
ever, seems to be in favor of a recession of this formation, and there
is good reason to believe that it was at one time more extensive than
at present.

Many species which seem to be most at home in the mountain
formations also push down into the Bouteloua formation. Among
these may be noted Achillea lanosa, extending down the draws,
Geranium caespitosum, Gilia pinnatifida, G. aggregata, Campanula
petiolata, and many other species,

Succession.
PRIMARY SUCCESSION.
On rock.

What the primary succession has been in this region cannot be
determined. The succession on rock undoubtedly began with the
lichen. On the most exposed rocks of the lime ridge Staurothele
wmbrina and Lecanora previgna are practically the only lichens
found. On the other rocks the lichens are much more mixed and
there seems to be good evidence of the accepted succession for
lichens: first the crustose; then the more foliose forms like Lecanora
rubina and L. rubina opaca; and finally Parmelia conspersa. On
the mesa, where the rocks range from 5%" in diameter to coarse
Sravel, Parmelia conspersa is the most important lichen, although

‘™odina oreina and Lecanora calcarea are also common. Placo-

188 BOTANICAL GAZETTE [SEPTEMBER

dium elegans, which is also common on rock, seems to require pro-
tection and is probably one of the later species to appear. The
same may be said of Lecanora subjusca allophana, one of the impor-
tant lichens, which succeeds best in crevices.

The rock lichens occurring within this region belong to the
primitive lichen formation.

Factes: Parmelia conspersa (Ehrh.) Ach., Rinodina oreina (Ach.) Mass.

PRINcIPAL spEctEs: Lecanora calcarea (L. )Sommerf., L. subfusca allophana
Ach., L. previgna (Ach.) Nyl., L. rubina (Vill.) Ach., L. rubina opaca Ach.,
Placodium elegans (Link) DC., Buellia petraea montagnaei Tuck., Lecanora
previgna revertens Tuck., L. xanthophana dealbata Tuck., Staurothele umbrina
(Wahl.) Tuck.

SECONDARY SPECIES: Placodium cerinum (Hedw.) Naeg. & Hepp., Aceto-
spora chlorophana (Wahl.) Ach., Biatora crenata dealbata Tuck., Heppia
Despreauxii (Mont.) Tuck., Placodium vitellinum (Ehrb.) Naeg. & Hepp.,
Umbilicaria rugifera.

This formation occurs on all exposed rocks, with the possible
exception of the Permian, which in most places disintegrates too
rapidly to support a lichen flora. With the exception of the last
four species, all of the species occur on exposed surfaces. The last
four and Placodium elegans prefer shaded or at least somewhat Pro
tected situations, Throughout the mesa this formation has been
almost completely replaced by the Bouteloua formation. On hills
and more exposed rocky situations it is sometimes as important as
the grass formation with which it alternates. With the more comr
plete disintegration of the rocks this formation will entirely disappe™

On alluvium.

Uncertain as is our knowledge of the primary succession on rock,
it is much more certain than our knowledge of the primary succe>
sion on alluvium. A careful study of the formation, and in partic:
ular those places which are least covered with vegetation, seems to
aid in forming an idea of this primary succession.

Near Eastonville, in the region lying between the Bouteloua
formation and the invading pine formation, an open area is being
invaded by the following species: Potentilla coloradensis, Thermops®
rhombijolia, Erigeron glandulosa, Paronychia Jamesii; followed by
Arenaria Fendleri, Muhlenbergia gracilis, Bouteloua oliogostachy4,

1906] SHANTZ—VEGETATION OF THE MESA 189

Gutierrezia Sarothrae, Artemisia canadensis, and Tetraneuris glabriu-
scula, Thisis probably the best example of primary succession found
by the writer. The absence of ruderal species is especially noticeable.

On the mesa the Andropogon scoparius consocies seems to be
most primitive. In places not yet covered with vegetation, where
the alluvium is nearest what it seems to have been originally, this
grass is most abundant and together with Eviocoma cuspidata is
the first to disappear in passing from this exceedingly open association
to the more stable or closed Bouteloua formation. Eriognum alatum,
E. Jamesii, Tetraneuris glabriuscula, and Machaeranthera cicho-
raced are generally present; but since they extend into the true
Bouteloua formation they are probably not as much a part of the
primitive association as the plants mentioned above.

The lime ridge vegetation is probably primitive, as shown by the
following quadrat:

Lesquerella alpina. . . . . s2 Ofreocaryathyrsiflora . . . . 3
Gutierrezia Sarothrae . 2. 5 Gaura coccinea . $f tahoe
Lithospermum linearis . 4 Machaeranthera cicluccaton eee

Total sites covered, 5 to6 %.
At some distance from this, a quadrat shows the sn do

Lesquerellaalping. . |. 31 Eriogonum Jamesii 3
Grindelia squarrosa - . . 4 Tg Boebera papposa- 3
Hedeoma nana ' 13 Lithospermum linearis. :
Gaura coccinea. 62 leo BS pelnola 2 raeaie J
Bouteloua ligostachya. oe Gos Ge a 2
Aristida lon ngiseta wo Vo a erat teres I
Stipa Vase aeyh

: > : ; 3
Total surface covered, 7 to 8%.
The entrance of Bouteloua is already noted, as is Aristida long-
isela. A more distant point will show the following a

Bouteloua Oligostachya .. .. . $4 Lithospermum linearis 6

theropogon curtipendulus . . 28 Aristida longiseta 3
Grindelia squarrosa 5 wt; . 16 Eriogonum Jamesii 4
Boebera papposa 57. Pentstemon angustifolis I
Malvastrum coccineum 7 Salvia linearis . _
Lesquerella MDA Ge ee Stipa Vaseyi *
Helianthus annuus... (|, 4.48 Salsa. Trae :
Gutierrezia Sarothrae . . . 13 Artemisia frigida 3

Chenopodium leptophyllum . . to Evolvulus pilosa .

Total surface covered, 18 to 20%.

Igo BOTANICAL GAZETTE [SEPTEMBER

- These quadrats are all on steep slopes where the soil is more or
less broken. The first quadrat is in pure disintegrated limestone;
some gravel has been washed into the second quadrat; while the
third is a mixture of gravel, clay, and lime. The difference in soil
is of no importance in this connection; since in other places the same
succession occurs on the pure disintegrated limestone. In the first
quadrat the water content varies from 19 to 6%; in quadrat 3 it
varies from 19 to 2%; while in the second quadrat the per cent. of
water is intermediate. As one passes from the first quadrat to the
second and then to the third, the facies of the Bouteloua formation are
found making their appearance; in fact, the flora, aside from a few
ruderal species and Lesquerella alpina, is decidedly of the Bouteloua
formation.

The native species, which are referred to as ruderal, show the great-
est ability to occupy new ground and they are the most important 1m
secondary succession. It seems reasonable to suppose - that they
were also very active in invading the newly formed alluvium, and
that, if any of the existing species have taken part in the primary
succession, these plants are to be sought among the native ruderals.
This can be more clearly understood after a consideration of sec
ondary succession.

SECONDARY SUCCESSION.

The repeated changes which have taken place in the formation
of the great plains have manifestly been accompanied by changes
in vegetation. What these changes have been can only be inferred
from the changes which are now taking place wherever, in the pre?
of erosion, there is a cutting away or deposition of material, These
successions in a certain sense are primary, but will be discussed
under secondary successions.

Biotic agencies.
There are so many chances for observing secondary successions
that the experimental denuded quadrat was not deemed necessat»
although several of these are now under observation. There 47
many trails which lead through the Bouteloua formation where the
ground has been but slightly disturbed (fig. 12). The travel has
simply worn off and killed the original vegetation. After having

1906] SHANTZ—VEGETATION OF THE MESA IgI

been in use for a longer or shorter time they are generally aban-
doned. The soil is hard, in fact has never been broken, but since
there is no vegetation, an opportunity is afforded for the entrance of
new plants. These trails have not been used in wet weather, and
they are therefore never cut up and no loose soil is formed. The
succession here is first ruderals like Boebera papposa, Amaranthus
‘blitoides, or Verbena bracteosa. These seem to be most successful

Fic. 12.—Trail invaded by Boebera papposa; Bouteloua formation at the sides.

mvaders of such trails. The grasses of the formation come in slowly,

Muhlenber gia gracillima generally in advance of, or with Schedon-
nardus paniculatus, Sitanion elymoides, Athero pogon curtipendulus,
and ultimately Bouteloua oligostachya, It is not an uncommon thing
to find these old trails only distinguishable by the depression of
Surlace and completely covered by the Muhlenbergia gracillima
Consocies. Where the same trail leads through the purer growth of
Boutelowa oligostachya, it is not so rapidly covered, and when it
pésses through the Bouteloua hirsuta consocies it remains open for a
Stl longer period,

Ig2 BOTANICAL GAZETTE [SEPTEMBER

The mesa road was originally of the type just mentioned. During
wet weather the road would be cut up to a certain extent and drivers
would then turn to one side in order to escape the rough road. The
new path has always been formed on the southwest side. This road
has been in constant use for several years with the result that plants
have been destroyed continually on one side, and have invaded the
old roadways from the other. These old roadways show a great
many stages in succession.

The road is left in a somewhat roughened condition and the
most important species to enter is Stipa Vaseyi. It thrives best in
newer situations and disappears gradually as on* passes back from
the well-formed frontal zone. The stable condition which it brings
about is not favorable for the growth of the seedlings and it dies out
after ten to fifteen years. Aside from the entrance of the annual
ruderals Boebera papposa, Amaranthus blitoides, and Verbena brac-
teosa, it represents the first stage in the succession which will result
ultimately in the Bouteloua oligostachya formation.

The species which ultimately take possession are usually deter-
mined by the adjacent formation. Where Muhlenbergia gracillima
is dominant it usually appears much in advance of Bouteloua
oligostachya; but where the latter is dominant, it is usually in advance.
Stipa Vaseyi, the first perennial to appear, is usually accompanied
by the annuals Boebera papposa, Salvia lanceolata, P olygonum
aviculare, Amaranthus blitoides, and a number of other species.
The grasses enter in about the following order: Schedonnardus
paniculatus followed by Sitanion elymoides and Aristida longiseld,
and ultimately by Muhlenbergia gracillima and Bouteloua oligostachy4.
With these grasses there appear many annual ruderals and also io
following: Senecio s partioides, Gutierrezia Sarothrae, Artemisia frigid,
Carduus undulatus, C. plattensis, and Pentstemon angustifolius.

A transect of the mesa road will give more detailed information
regarding the sucessions found here (see transect). This transect 1S
one meter wide. In the plot each division represents one meter, 22
the most important species in each square meter is placed at the left,
and the other species in order of their importance are added to the
right.

1906} SHANTZ—VEGETATION OF THE MESA 193

34 [2M BiG 2
a4 * ‘
a: M Bl Afl iG A, Atheropogon curtipendulus
258 1554 M\ Af| |@ Aa, Atriplex argentea
6M B HAY: G\Ss Ab, Amaranthus blitoides
M BS Bo AF &'C S/ Ss Ad, Astragalus Drummondii
? |
| 1M £ ov Pp Ad TAN EVA t Aj, Artemisia frigida
! ISP SuiSsiG B St Cul Me Al, Aristida longiseta
t ISP G |Ss| Ad Af Me ulSo| Va ya
| [SASvB1G IA SL ALC. ees a
a Bo Sv BISIIE y M Bh, Bouteloua hirsuta
it Bol SviSUSs C1 Al Bo, Bouteloua oligostachya
os oF ~ *
SH IS/ 8 SviSs. 57M | St |SoSer C, Calamovilfa’longifolia
cod i =
= é : ~ [ V iSe Pa\St vd Ss\Te Ca, Cycloloma atriplicifolium
rs
" r r ar Ae OMe: _ Va\ a C Se Cl, Chenopodium lepidophyllum
be vive ~) Ka is
3 vl (SelB iSZ| Ss ALE Vall Cu, ee undulatus
3} PSV A 5S Sol Ad. Ci Ss Val S Ee, Eriogonum effusum
' | vi B Bol SA Se C1 | l G, Gutierrezia Sarothrae
of psuict Va,S/ L |PalTe I, Iva xanthifolia
z ca Advll Vv L, Lappula occidentalis
SLI@SviaS _|SiISs :
3 B Mc, Malvastrum coccineum
< aes 2, |_5, Y |PalS Se Pa. Pol a
= ‘ v BSI Va a, Polygonum aviculare
Sv B 1S/ Sc \Mb iCall |e S, Sideranthus spinuiosus
Sc, Sporobolus cryptandrus
Se, Sitanion elymoides
SI, Salvia linearis
So, Senecio oblanceolatus
g Sp, Schedonnardus paniculatus
& ! | Ss, Senecio spartioides
= 8 St, Salsola Tragus
| ;
ate 8 a Str, Solanum triflorum
B 3 = Ss Sv, Stipa Vaseyi
patent | S'Ss\Aa
} Bo! | Me Te, Townsendia exscapa
§ o| 15 S & Ss Tg, Tetraneuris glabriuscula
& a o : Y Ss Ty |Te Va, Vicia americana
3 oO] | YS |als Vb,jVerbena bracteosa
~ { \ { i - “
= dt 8 LM d G|S |Ee Y, Yucca glauca
: AME 81S 73 \Te|be TRANSECT OF MESA ROAD
Cah [50 | MQ |BAA s
Se

194 BOTANICAL GAZETTE [SEPTEMBER

This transect is typical of the greater part of the road. Near
Gleneyrie Machaeranthera cichoracea appears in abundance in
the frontal zone. At the lower end of the mesa road is found
considerable variation. Cleome serrulata forms the frontal zone,
and with this Boebera papposa, Xanthium commune, Polygonum
aviculare, Verbena bracteosa, Munroa squarrosa, Amaranthus bli-
toides, Solanum rostratum, Chenopodium album, and Malvasirum
coccineum. Just back of this, on a portion of the old roadway, is
Stipa Vaseyi, with Boebera papposa, Euphorbia dentata, Chenopo-
dium leptophyllum, Ambrosia artemisifolia, Sophora sericea, Poly-
gonum aviculare, Schedonnardus paniculatus, Bouteloua oligostachya,
Muhlenbergia gracillima, Artemisia frigida, Xanthium commune,
Carduus undulatus, Iva xanthijolia, Asclepias pumila, and Salvia
lanceolata. The advance on the graded graveled part is made
almost entirely by annuals, Boebera papposa, Verbena bracteosa,
Amaranthus blitoides, or in rare cases Solanum rostratum is most
important, while other species are generally present in reduced
numbers. The soil in these cases has been packed down and Stipa
Vaseyi does not enter.

The old mesa road is not followed by the new in all places. In
the lower end of the mesa it turns to one side. Here through the
original formation, it was only a path. It had been worn down
and when abandoned the soil, through the agency of frost and rain,
had loosened and fallen in at the sides, This road is now revege
tated with Stipa Vaseyi, which is in many places replaced by Muh-
lenbergia gracillima and Bouteloua oligostachya. In one place this
vegetation is practically identical with the formation.

The successions on trails vary considerably in different parts of
the region. As one travels from Colorado Springs to Palmer Lake
changes are soon noted. A short distance above Colorado Spnng
Boebera papposa becomes less abundant and the first species 10
invade the roadway is Plantago Purshii. Above Monument 5!?¢
Vaseyi drops out as an invader, and the principal species which enter
are Polygonum aviculare, Lappula occidentalis, Verbena bracteosa,
Amaranthus blitoides, A. retroflexus, Salvia lanceolata, and Ramet
acetosella. Below Monument a short distance the following SY“
cession was noted: +The advancing zone was made up of Lepidiu™

1906] SHANTZ—VEGETATION OF THE MESA 195

apetalum,Polygonum aviculare, Artemisia frigida, A. canadensis,
Verbena bracteosa, and Plantago Purshii; while farther back were
found Bouteloua oligostachya, Schedonnardus paniculatus, Chrysop-
sis villosa, Arenaria Fendleri, Gilia aggregata, G. pinnatifida, Senecio
oblanceolatus, Gutierrezia Sarothrae, Koeleria cristata, and Sitanion
elymoides; followed by the Bouteloua formation in which Bouteloua
oligostachya, Stipa comata, and Arenaria Fendleri were most
important,

The stages of a succession which converts a denuded trail into
the Bouteloua formation are not marked. First there is, as a rule, the
entry of many annual ruderal species (fig 12). This in many cases is
followed by Stipa Vaseyi, followed by Schedonnardus paniculatus,
Sitanion elymoides, and Aristida longiseta, as well as many other
secondary species of the formation, and these in turn by the facies
of the grass formation. In some places Stipa Vaseyi does not enter
and here may be found many other species. Among the more
important are Schedonnardus paniculatus, Gutierrezia Sarothrae,
Chrysopsis villosa, Artemisia frigida, A. canadensis, and many
other species, followed by the facies of the grass formation.

Near Cheyenne Mountain a number of abandoned corrals show
the following as the most important invading species: Schedon-
nardus paniculatus, Artemisia canadensis, Solidago sp., Artemisia
jrigida, A, gnaphalodes, and a number of secondary species—
Petalostemon purpureus, Thelesperma gracile, Chrysopsis villosa,
Pulsatilla hirsutissima, Lacinaria punctata, Sporobolus cryptandrus,
Aristida longiseta, Bouteloua hirsuta, Aragallus Lambertii, and the
Tuderals Boebera papposa and Euphorbia glyptos perma,

A denuded quadrat showed during the third summer Artemisia
canadensis, Geranium caes pitosum, Pulsatilla hirsutissima, Chrysopsts
villosa, and Artemisia Iudoviciana. A second corral showed
Artemisia canadensis and A. jrigida as the chief invaders, with many
other species coming in, of which those most important are Schedon-
nardus paniculatus, Bouteloua oligostachya, and Koeleria cristata.
The early stages of these successions vary greatly. In the study
of a large number the following plants are found to enter first:
Boebera pap posa, in the mesa region and adjacent areas; northward
toward Palmer Lake, Plantago Purshii or Polygonum aviculare;

196 BOTANICAL GAZETTE [SEPTEMBER

and farther east Picradeniospsis oppositijolia, sometimes accom-
panied by Malvasirum coccineum, :

A number of graded roads have been built very recently and
these show only the very first vegetation, a ruderal annual vegeta-
tion. The boulevard, which runs from Colorado Springs to
Manitou, is an older road of this type, having been built for about
thirteen or fourteen years. The first permanent succession on this
road within the Bouteloua formation was Stipa Vaseyi, which is
now giving way to Muhlenbergia gracillima and Bouteloua oligo-
stachya, Many other species came in, among which the more
important are Sitanion elymoides, Aristida longiseta, Schedonnardus
paniculatus, Helianthus annuus, Quincula lobata, Astragalus bisul-
catus, Sophora sericea, Grindelia squarrosa, with other plants from
the formation, as well as ruderal species.

One of the transects of this road deserves special mention. There
is a cut here of about 2™, and the road runs north and south. The
differences in the east and west sides are due entirely to the differences
in exposure, and to its effect upon temperature and water content.
The west side, which receives the most light, has first a distinct zone
of Petalostemon oligophyllus, back of which there is a mixed zone of
Boebera papposa and Xanthium commune; this is followed on the
bank by Stipa Vaseyi, and this in turn by a crest zone largely of
annuals. The east side shows first a zone of Xanthium commune
followed by Stipa Vaseyi, mixed with Schedonnardus paniculatus,
Boebera papposa, Psoralea tenuiflora, etc.; and this is followed on
the steep unstable soil by annuals. Back of the annuals is the
Bouteloua formation in which Muhlenbergia gracillima predom-
inates.

There is a great deal of variation in the species which first appear:
Almost any one of the species cited under the ruderal formation
may dominate in certain places, but the more or less typical examples
mentioned above should serve to give an idea of the succession on
roads.

Reservoirs are generally built where only one side needs to be
dammed. The outer slope of the dam is invaded in the same Way .
road would be. An interesting exception is found at Palmers
reservoirs. The large reservoir, which was built in 1902, had by

1906] SHANTZ—VEGETATION OF THE MESA 197

1904 covered the bank chiefly with Stanleya glauca and Mentzelia
decapetala. A great deal of the soil of this bank was hauled in from
the lime ridge region, and with it, the seeds of Stanleya glauca were
carried in. In one of the other reservoirs, which is several years
older, Medicago sativa was predominant. Normally, Boebera
papposa, Stipa Vaseyi, and other ruderals would be expected to
appear first.

A new reservoir constructed on the mesa in 1904 showed during
1905 the following species: Boebera papposa, Salsola Tragus, Senecio
spartioides, Artemisia frigida, Senecio oblanceolatus, Argemone inter-
media, Menizelia nuda, Polygonum aviculare, P. Douglasii, Euphor-
bia robusta, Yucca glauca, Chenopodium album, Gaura coccinea,
Cleome serrulata, Petalostemon purpureus, Amaranthus blitiodes, and
A, retroflexus.

In building roads and reservoirs it often happens that several
meters of surface soil and all the vegetation is removed. Succession
is different here from the places already mentioned. The annual
ruderals.do not appear in such great numbers. Among the species
which enter are Argemone intermedia, Mentzelia ornata, Petalostemon
oligophyllus, P. purpureus, Sitanion elymoides, Aristida longiseta,
Munroa squarrosa, and other common hillside plants, since the soil
here is usually gravel.

Broken areas.

Here and there on the plains are found areas which have been
plowed and planted, but have been abandoned because of the scanty
water supply. The succession of plants here is much the same as
on graded roads, but is usually more uniform. An abandoned
garden patch showed the following year the facies Anogra albicaulis,
with Chenopodium album and Helianthus annuus as the principal
species. An area on top of the mesa showed almost a pure stand of
Boebera Papposa; while still another showed Schedonnardus panic-
wlatus. Artemisia frigida sometimes enters denuded areas and
dominates the early stages of the succession. During 1904 a tract
was seeded with Lolium perenne; the following summer it showed
Boebera papposa and Verbena bracteosa, as well as Polygonum
aviculare, Salsola Tragus, Artemisia frigida, Lolium perenne,

198 BOTANICAL GAZETTE [SEPTEMBER

Solanum triflorum, Senecio oblanceolatus, and S. spartioides; also a
very few young plants of Yucca glauca, Argemone intermedia,
Carduus undulatus, and Tetraneuris glabriuscula.

The usual flora on the hills of the prairie dog is Anogra coronopi-
jolia, Malvastrum coccineum, Munroa squarrosa, Amaranthus
blitoides, Picradeniopsis oppositifolia, Boebera papposa, and Arle-
misia frigida. Muhlenbergia~ gracillima is the most effective in
reclaiming the old deserted hills. In fact, in looking over a deserted
dog town the location of the old dog hills can be determined at once
from the fact that although the surrounding vegetation is dominated
by Bouteloua oligostachya, the location of the old hills is marked by
a community of Muhlenbergia gracillima.

Near Pring, Colo., an abandoned field showed the first year
Helianthus petiolaris, with a less amount of Boebera papposd,
Malvastrum coccineum, Solanum rostratum, Lappula occidentalis,
Verbena bracteosa, and a very few plants of Artemisa frigida,
Atheropogon curtipendulus, Schedonnardus paniculatus, Carduus
undulatus, and Eriogonum annuum. Here are found three very
distinct sets in the succession. First, annual species, followed by 4
group of ruderal species, and this in turn by perennials from the
Bouteloua formation. In another place Thelesperma intermedium
was the first species to enter. Near Falcon, Col., an abandoned
field showed after two years Helianthus petiolaris and also Munroa
squarrosa, Lappula occidentalis, Chaetochloa viridis, Plantage
Purshii, Amaranthus retroflecus, and Ptiloria ramosa. In some
places Bouteloua oligostachya was entering. Another field which
had been abandoned for about eight years showed 5S porobolus
cryptandrus, Aristida longiseta, Schedonnardus paniculatus, Cenchrus
tribuloides, as well as Senecio oblanceolatus and Munroa squarros’s
a few annuals, the more important of which were H elianthus
petiolaris, Verbena bracteosa, and Cryptanthe ramosissima. Into this
area Bouteloua oligostachya was pushing its way and had in places
near the edge of the field almost replaced the other species.

Several miles west and south of Fountain, Col., a most interesting
stage of succession is shown. The surrounding vegetation is of the
Bouteloua oligostachya consocies with very few primary and secondary
species. An area which had been broken and abandoned showed

1906] SHANTZ—VEGETATION OF THE MESA 199

the Muhlenbergia gracillima consocies almost entirely replacing the
earlier stages of the succession. A very little Boebera papposa and
Schedonnardus paniculatus remained, while about an equal amount
of Bouteloua oligostachya was invading and will after a number
of years replace the Muhlenbergia.

As long as the ants are alive, they remove all vegetation for some
distance around their hills. In low places Cleome serrulata may
form a semicircular zone on the lower side of this denunded area.
Helianthus annuus, H. petiolaris, Stipa Vaseyi, and many other
species may also be found in this situation. The most common plant
to develop in this area is Munroa squarrosa, which often forms a
perfect zone.

Erosion.

The dry soil is easily washed away by heavy rains. This forms
loose soil at the base of the hills and also leaves broken places from
which the soil is removed. On the hillsides there are often produced
natural terraces, each of which ends in a broken edge. During the
rains these terraces are cut back and new soil is exposed. These
places may be occupied by Boebera papposa, Salsola Tragus, or other
annuals, but generally Stipa Vaseyi is the invading species. Here
it serves to bind the soil and prepare the way for Muhlenbergia
gracillima and Bouteloua oligostachya.

In the low draws there is generally a hollow washed out below
the terrace, and as a result of the falling in of the soil when dry there
is found both loose and undisturbed soil. These places are marked
by a growth of Sti pa Vaseyi, with Boebera papposa, Solanum ros-
tratum, and often Salvia lanceolata, Helianthus annuus, Verbena
bracteosa, Salsola Tragus, Xanthium commune, and Leptilon cana-
dense. Places such as this are very much like the ordinary draw
where more or less of the soil which was washed down from the hills
is deposited. Conditions here are also almost the same as in the
alluvial fans which are formed at the bases of all the ravines, whether
they be small or large. Here new soil is deposited during every heavy
rain, and as a result the slow growing grasses such as Bouteloua
oligostachya and Muhlenbergia gracillima cannot thrive. Stipa
Vaseyi is the most successful plant of such habitats. It marks the

200 BOTANICAL GAZETTE [SEPTEMBER

dry water courses and also all of the alluvial fans. Succession
here is practically the same as on any ruderal area. In addition to
Stipa Vaseyi there is usually found Boebera papposa, Salvia lanceo-
lata, and in some cases Xanthium commune and Cleome serrulata.
When the soil has become more stable Stipa Vaseyi slowly gives
way. Artemisia frigida is now one of the first species to appear, and
is often dominant after Stipa Vaseyi has disappeared entirely. This

Me riol lix

IG. 13.—Blow-out; the prominent plants are Muhlenbergia gracilis,
serrulata, re emisia canadensis, and Andropogon scoparius; Calamov alfa longifolia
in the background.
is followed by Muhlenbergia gracillima, and after a number of yea"
this is replaced in turn by Bouteloua oligostachya.

On dry sandy ridges blow-outs are often found (fig. 13):
succession here is usually Polygonella articulata, Cycloloma airipiicr
jolium, Carex sp., Muhlenbergia gracilis, Sporobolus cry plandrus,
Artemisia canadensis, Thelesperma gracile, Eriogonum annuum,
Meriolix serrulata, Chrysopsis villosa, and Andropogon scopar ws.

The

1906] SHANTZ—VEGETATION OF THE MESA 201

The most important plant occupying the alluvium deposited by
permanent streams is Melilotus alba. Species of minor importance
are Juncus bujonius and Riccia crystallina.

ANOMALOUS SUCCESSION.

When biotic or physical agencies bring about sufficient change
in the habitat, the result is an anomalous succession. The change
of habitat may be gradual and yet the effect on the succession be
such as will change entirely the ultimate formation. We may also
have the succession interfered with in such a way as to hasten the
ultimate formation, to cause it to become more stable in a shorter
time, or to retard the succession or reduce it to a more primitive
condition.

Due to grazing.

The influence of grazing is very clearly seen by comparing fenced
areas with those that have not been protected from grazing animals.
Cattle, and to a less extent horses, are the only animals that have
grazed within this region in recent years.

Near the lower end of the mesa is Colorado City, the old territorial
capital of Colorado and known as one of the oldest towns in the state.
For fifty years it has been the custom to have a herd boy drive the
cattle out on the adjacent areas to graze each day and bring them
back each night. Colorado Springs, a more recent city, also sends
its herds out on the same area. It will be well, at first, to see what
effect this has had upon the Bouteloua formation. In those parts of |
the formation where grazing has not played a part the formation is
very open, while in the grazed portions it is more closed. In the
open formations many species appear with the grasses, while in
the more closed formation these species are almost entirely absent.
A typical quadrat from the south mesa which has been grazed shows
the following species:

Muhlenbe

tgia gracillima . 23 33% Sideranthus spinulosus 3
Bouteloua oligostachya. . 24 12 Wi Weeut rack ‘concuieues 5
“ropegon curtipendulus 1 Townsendia exscapa . . 2
a GS 2 Echinocereus viridiflorus . I
Boebera Papposa. . . 36

Total surface covered, 45 to 50%.

202 BOTANICAL GAZETTE [SEPTEMBER

In some of the draws the preponderance of Muhlenbergia gracil-
lima is even more marked. Near the above quadrat, in a portion
protected from grazing, a quadrat would show:

Bouteloua oligostachya : 18 % Artemisia frigida . .
Muhlenbergia gracillima. 2.5 Artemisia gnaphalodes
Aristida longiseta. . . 4.5 Gutierrezia Sarothrae

Chrysopsis villosa .
Thelesperma gracile .
Echinocereus viridiflorus.
Opuntia polyacantha .
Euphorbia robusta

Sitanion elymoides
Eriogonum alatum
Pentstemon angustifolius .
Carex pennsylvanica .

rw PO CO
mre NF ND OH eS

Total surface covered, 27%.

In a portion of the mesa which has been grazed, but not to such
an extent as the first quadrat given, is found:
Bouteloua oligostachya. . . 22% Artemisiafrigida . . - - - 570°

uhlenbergia gracillima z

It cannot be stated positively that this condition is entirely due
to grazing. It seems likely, however, that grazing would favor the
development of grasses and tend to destroy the other plants, partic:
ularly the dicotyledons. There is a very noticeable difference >
adjacent areas when one is protected from grazing. The prepot
derance of Bouteloua oligostachya and Muhlenbergia gracillima, and
the paucity of higher spermatophytes in the grazed area is the chie
difference. This seems to be the exact condition which would come
about by natural succession and the grazing in this case hastens this
succession. The more primitive parts of the formation and those
which have not been grazed are much alike. Grazing, when es
too severe, favors the development of the facies of the formator:

Still another condition due to grazing should be considered.
Near Colorado City, and particularly in the region lying ba
Colorado City and Colorado Springs, the grazing has been very
severe. The result here has been first to drive out most plants pei
than the grasses, and ultimately even to destroy Bouleloua oliga-
stachya and Muhlenbergia gracillima to a great extent. A few seh
such as Astragalus bisulcatus, Chrysothamnus graveolens, se"
squarrosa, and others which are not touched by grazing an?
still survive; but the character, aside from a few of these asoneagt
now almost entirely marked by annuals. The successioP

1906| SHANTZ—VEGETATION OF THE MESA 203

scene practically that which follows on a denuded area. Salvia line-
aris, Atriplex argentea, and Bouteloua prostrata are here the principal
species. With these are found many of the ruderal plants as well as
ah following important perennials: A gropyron occidentale, Astragalus
bisulcatus , Sophora sericea, Vicia americana, and a very little Bouteloua
oligostachya, Quincula lobata, and Phyllopterus montanus.

The effect is to delay the succession or to cause it to return to a
more primitive condition. The grazing does not change the Boute-
loua formation into another formation, since grasses seem to be
especially adapted to these conditions.

he effect of grazing is very different on the thicket formation. -
Wherever cattle are allowed to crop the thicket formation very closely,
the facies are completely killed. This is the most noticeable in the
ci aa oaks, which are killed by the entire loss of chlorenchyma
oe attacked by cattle before any of the other facies

of the thicket formation.
oo Honat the region shows that on the mesa near Colorado
the ar a formation has been replaced almost entirely by
parvifolia sy tenes Only scattered bushes of Cercocarpus
a ee sia sptaaaa are found and these much reduced in
SE a aes lies in the fact that this portion has been
City. >The ro an the part which is farther removed from Colorado
aiid the ans lacie of the old thicket can be seen in many places,
nee Sp m : le succession which have produced a grass forma-
plant growth . : icket formation may be traced. There is a scanty
ne, > er these shrubs. When they are killed outright
come in in - vas plant invasion, and as a result the ruderals
Sli st ance. Chenopodium album may be one of the
destroyed oop ae at this time, especially if the cattle have
the shrubs have be e under vegetation. At other places where
Same as the tear ising down the succession may be much the
formation. As a ; . uccession and result in the typical Bouteloua
The result here is ne e the shrubs are gradually reduced in size.
the shrubs are eat = the grasses slowly encroach upon the area as
the: derek is ower, and as the clump becomes more open
S. neo-mexicana, A - Saree: Agropyron occidentale, Stipa comata,
, Atheropogon curtipendulus come in slowly; Coleo-

204 BOTANICAL GAZETTE ° [SEPTEMBER

santhus umbellatus and Chenopodium Fremontii disappear. When
the shrub ultimately dies and breaks up, there is a very small ruderal
place in which the succession is identical with that already described
for denuded places. Grazing changes the thicket formation to a
grass formation, and the more rapid the change the more nearly it
approaches the ordinary ruderal successions.

Due to drainage.

Drainage is not an important factor, but it seems best to consider
here those changes which result when an irrigated area is left without
irrigation, a ditch abandoned, or the water of a stream turned aside
causing the bed to become dry.

Examples of the first case mentioned are not found excepting
where, because of lack of attention, the water does not flow evenly
over a meadow. The succession here is gradual, forms like Erigeron
flagellaris, Vicia americana, and Astragalus hypoglottis taking the
place of the more hydrophytic grasses and rushes. If the change of
habitat is abrupt, most of the species die and a ruderal. succession
follows. When the change is very gradual, the species mentioned
above, together with Agropyron occidentale, take the place of the
rushes. Bouteloua oligostachya often appears in this stage of the
succession, but Muhlenbergia gracillima is one of the last to appeal

In abandoned ditches a mixed formation is generally found. »
this habitat the following species of the mesophytic bank formation
may continue for a long time: Clematis ligusticijolia, Xanthium
commune, Symphoricarpos occidentale, Stachys palustris, Erigeron
flagellaris, and Vicia americana. The last two species are elements
of the Bouteloua formation and are able to adapt themselves to Les
change of habitat. Of the grasses of the Bouteloua formation,
Bouteloua oligostachya and A gropyron occidentale are the first to enter.
They appear much earlier than Muhlenbergia gracillima, and thrive
even better in these transformed ditches than in the Bouteloua for-
mation proper.

There is only one example of the effect of a change in
water course. This is not complete, but enough water
taken from Camp Creek to cause it to be dry for a greater P
year. The first and most noticeable effect has been the

the natural
has beet
art of the
death of

1906] SHANTZ—VEGETATION OF THE MESA 205,

the trees, Populus angustifolia and P. deltoides. This condition has
obtained for only about three years, and the effect thus far has been
destructive. The bank species, with the exception of those that
are able to exist in more xerophytic habitat, have died, and aside
from the entrance of a very few ruderals there has been no marked
succession as yet.

Due to irrigation.

The changes produced by irrigation are complete and varied.
Where a ditch passes through the Bouteloua formation in places
where there is seepage, the first stages of the succession which lead to
the irrigated meadow formation arefound. The effect here is usually
the better development of A gropyron occidentale, and at the same
time the disappearance of Muhlenbergia gracillima. Bouteloua
oligostachya also grows more rank than where not irrigated. This
Succession is exceedingly variable, probably because of the variable
water supply, and the stage of the succession is an index to the amount
of water added. In some places the meadow flora is reduced largely
to rushes and other hydrophytic plants, while in other places Boute-
lowa oligostachya, Erigeron flagellaris, Vicia americana, and Astraga-
lus hypoglottis are most important.

n the bank formation the conditions are varied. Between
the water and the xerophytic formation through which the stream
or ditch runs, there are all gradations from hydrophytic to xerophytic.
But to divide this formation in regard to water content of the soil
Would not be practicable. Another condition makes the formation
more complex, In the ditch formation, there is, besides the invasion
of the mesophytic and hydrophytic plants, the entrance of the ruderal.
When the ditch is first made the ruderal formation makes its appear-
ance. At almost the same time thé mesophytes and hydrophytes

hag The ruderal formation always tends towards self destruc-
Bee Here the result is that the outer portion of the ditch is ulti-
te 4

on th Occupied by the characteristic Bouteloua formation, while

I : inner the more mesophytic bank species become established.

ra os ultimate bank formation the line of separation from the grass
‘mation is very distinct.

" Many of the irrigation ditches a condition prevails which

206. BOTANICAL GAZETTE [SEPTEMBER

prevents the development of the ultimate stage of the succession.
Each year the bottom of the ditch fills up with silt which is removed
to the bank the following spring. This forms a new soil for the
entrance of ruderal species, and as a result the bank returns to a
somewhat primitive condition.

Another factor of importance here is the fact that during the winter
the ditch is empty the greater part of the time. This condition is
detrimental to the success of the species of the ultimate formation.
The result is that along these irrigation ditches are found various
stages of anomalous successions, which are checked repeatedly, or
even turned back by the reversion to more primitive conditions. The
successions are interrupted again and again, and this may account to
a great extent for the variable character of the bank formation.

° General discussion.

After careful study it is at once apparent that all parts of the
formation are not of the same age. The secondary successions
throw much light upon the structure as well as upon the development
of the formation. These exhibit rather well-marked stages. The
first is a ruderal consocies; the second, a society of the formation;
while the ultimate stage is a consocies of the formation. All of these
successions lead undoubtedly to the Bouteloua formation.

The successive deposition and erosion which has produ
Great Plains does not differ markedly from that which may
noted at the present time. The vegetation on new deposits of
passes through the typical succession leading from the ruderal to
the grass formation. Near the mountains the cutting back of the
gullies results in the establishment of the thicket formation, which .
preceded usually by the entrance of many of the secondary species
of the thicket and grass formation. The pine formation is usually
mixed with the thicket formation. When this cutting back of -
gullies exposes rocks of a sufficient degree of stability, the primitive
lichen formation precedes all others.

In many places gullies are cut back which are reclaimed at we
by the grass formation. The thicket and pine formations do es
enter. In these places the Andropogon scoparius consocies usually
becomes established.

ced the
be
soil

a

1906] SHANTZ—VEGETATION OF THE MESA 207

The elevated dry ridges are occupied by the Selaginella densa
formation in which Paronychia Jamesii is a prominent species.
This evidently represents a younger stage in a succession which will
give ultimately the Bouteloua formation. Among the most important
invading species are Stipa comata, Koeloeria cristata, and Bouteloua
hirsuta,

If these ridges are sandy, blow-outs often occur which result
when reclaimed in the Calamovilfa longifolia consocies (fig. 13). This
consocies thrives much better when not grazed. Grazing changes it
to the Bouteloua consocies. a

The Andropogon scoparius evidently represents an earlier stage
in the formation than the Andropogon furcatus or Bouteloua oligo-
stachya consocies. It occurs on the hillsides and also is found as an
early stage in the succession on denuded xerophytic areas. The
Study of secondary succession would lead also to the belief that
Muhlenbergia gracillima is only a stage, for here it is replaced
repeatedly by Bouteloua oligostachya.

The societies of the formation are, without exception, dominated
by species which are among the first to invade new areas. Their
Presence in the formation is largely due to historical reasons. To
this may be added the fact that the consocies which represent the
earlier stages, as for example the Bouteloua hirsuta consocies, have
by far the greater number of societies.

The Bouteloua oligostachya consocies represents the ultimate
Stage of the grass formation and is by far the most widely distributed
of any of the consocies of the formation.

This study of the Bouteloua formation was suggested by Pro-
fessor FREDERIC E. CLEMENTs, under whose direction it has been
carried on. To him and also to Professor Cuas. E, Brssey the
Writer wishes to express his thanks for many helpful suggestions
and criticisms. Thanks are also due to the following persons:
Professor F, D. HEaLp, for advice and criticism; Professor Wm.
STRIEBY, for generously giving me use of his laboratory for the
determination of water content; and to Professor F. H. Loun, for
meteorological data.

UNIVERSITY oF Missourt, CoLuMBIA. |

ad

CORTINARIUS AS A MYCORHIZA-PRODUCING FUNGUS’
C. H. KAUFFMAN.
(WITH ONE FIGURE)

THE study of the mycorhiza problems has received a new impetus
during the last six years by the appearance of extensive papers by
MacDovueat (1), STAHL (2), TUBEUF (3), HILTNER (4), and MULLER
(5). Considerable evidence has been adduced showing that in the
case of the endotrophic mycorhiza the organisms concerned act as
purveyors of nitrogen to the symbiont or host with whose roots they
are connected (6-7); furthermore, the organisms in some of these
cases have been quite exhaustively studied (8-9). On the other
hand, the fungi which cause the ectotrophic mycorhiza have not
been investigated except in a very few cases.

It is a noticeable fact as one looks over the literature, that the
larger part of the work hitherto attempted has been done on a basis
of several unknown quantities. One of these is the identity of the
fungus which causes the ectotrophic mycorhiza. The earlier writers
speak of the fungus as if it were a single species or genus. It was
thought for quite a time that the ectotrophic mycorhiza of European
trees was due in all cases to the tubers or truffles. WORONIN (10), 10
1885, showed that this cannot be true for Finland, where the tubers
are not found, but where nevertheless the mycorhiza are abundant.
KaMIENSKI(11) also found no truffles in the regions where he studied
the mycorhiza of Monotropa. ReEEs (12) was at first inclined t0
think that Elaphomyces was the cause of the mycorhiza of almost §
the trees he examined; later, he himself found mycelium of mycorhiza
which differed in structure from that of Elaphomyces.

The fungi whose fruiting forms have been definitely reported
as belonging to mycorhizal mycelium are comparatively few. Mac-
DovuGaL (1) gives a list of mycorhizal fungi whose identity has
been reported. The list is as follows: Fusisporium, Eurotium
Pythium, Nectria, Celtidia, Elaphomyces, Geaster, Boletus, Tn-
choloma, Lactarius, and Cortinarius. Of the non-mycelioid aie

* Contribution 89 from the Botanical Department of the University of Michiga®
’ Botanical Gazette, vol. 42] &

1906] KAUFFMAN—A MYCORHIZA-PRODUCING FUNGUS 209

which are known, Phytomyxa leguminosarum and Frankia are of
course the most prominent. It will be seen that the list is remarkably
small, especially if we remember that only one or two species is
referred to in each case. As we are only concerned with ectotrophic
forms, the first four can be omitted in the discussion, and if we con-
sider the evidence on which the symbiotic connection of the remainder
is based, we find the actual list even smaller.

In the case of the Boleti, WoRONIN (10), after declaring the tubers
out of the question, says: “‘Vielleicht gehért die hiesige Mycorhiza
einem anderen, ebenfalls unterirdischen Pilze an, dies will ich nicht
bestreiten, bin aber vielmehr geneigt anzunehmen, dass die oben
angefiihrten Boleten mit der Mycorhizen zusammenhingen.” It
seems that WorontNn himself was not very certain of the connection.
Elaphomyces was very exhaustively studied by REES (11), who
showed that it is undoubtedly connected with the pines in localities
Where the truffle occurs. Two species of Geaster, G. fimbriatus
and G. jornicatus, were shown by Noack (13) to be attached to the
roots of the spruce and pine.

When we come to a consideration of the agarics our knowl-
edge is meager indeed. Only one investigator, Noack (13), in
1889, has concerned himself with them. He found that five species
of this group were apparently mycorhiza-producers on the forest
trees of the locality where he made his observations. Two were
Tricholomas; one a Lactarius; and three were Cortinarii. He
merely makes the bare statement that they are connected with the
rootlets by their mycelial strands, which he could easily make out.
It is very probable that his observations are correct.

It seems to be appreciated that we need some investigation to
determine what fungus we are dealing with, so that problems which
have to do with the physiological side of mycorhiza may be under-
taken more intelligently; for it is just as likely that knowledge con-
cerning the fungus and its life history may lead to an understanding
of the relation of the two organisms as a knowledge of the tree would.
It seemed worth while, therefore, to report the identity of any such
mycorhizal fungi whenever the evidence seemed sufficient to make
It acceptable.

230 BOTANICAL GAZETTE [SEPTEMBER

OBSERVATIONS ON Cortinarius rubipes, sp. nov.’

In a previous paper (14) I pointed out that the members of the
genus Cortinarius were so constantly found in limited areas, and
some species in such close proximity to certain trees, that it seemed
likely that there was some connection. This last summer an effort
was made to find out to what extent this might be true. The season
was wet during the early summer, and although one finds few
Cortinarii as a rule before August, several did occur, and one of

Fic. 1.—Cortinarius rubipes, sp. noy.—Left hand sporophores show the mar if
rootlets and humus with strands of mycelium projecting above; right hand indiv ae
shows the roots with the short mycorhizal branches and the mycelial strands which
are attached to the base of the stipe-—Photographed by the writer.

these proved to be favorable for my purpose. It not only showed
beautifully its connection with the tree roots, but turned out to be
an undescribed species of Cortinarius.

It was found July 4, 1905, on the south slope of a smal
along the Huron River, near Ann Arbor, in a layer of humus ee
forest leaves. This species, as is indeed true of some other fleshy
fungi, is characterized by its brick-red mycelial strands and ag
By removing the surface soil it was possible to see the brick-re*
strands. intertwining with the rootlets apparently in all directions:

For description in full, see 8th Report Mich. Acad. Sci. 1906.

] ravine
d

1906] KAUFFMAN—A MYCORHIZA-PRODUCING FUNGUS Bis

But it was soon found that the reddish network extended along
definite paths. Beginning with a tiny rootlet, the fungus was fol-
lowed to a rather large root, apparently growing from a hickory.
On examination, however, it was found that the mycorhiza-bearing
root passed the hickory, and that all the roots of the hickory examined
were devoid of a colored mycorhizal fungus. On the other hand,
the root in question was now easily traced to a clump of red oaks,
of second year growth, which were distant at least 544" from the
starting point. Besides the hickory, the roots of a Crataegus which
crossed the oak roots were likewise devoid of the fungus in question.

The red strands were attached only to the small rootlets, and
where the roots extended below the black soil into the yellow subsoil
the mycorhiza gradually disappeared, facts which were known to
FRANK, STAHL, and others. The leaf mold along with the remains
of last year’s leaves forms a thin covering beneath which the young
buttons of the fungus are started.

About twenty paces down the slope, another troop of the same
species of Cortinarius was found. These came up only 30°" away
from a fine young sugar maple and close to one of its main roots.
Expecting that they were probably attached to the roots of an oak a
short distance away, I dug down carefully and found to my surprise
that the strands which were very luxuriant here were attached to the
rootlets of the sugar maple; even the small roots growing directly
from the base of the trunk were thickly beset by the strands. The
Sporophores were loosened and the attachment of the strands followed
from the stipe to the rootlets and thence to the tree. Several days
later on visiting the same hill, two more sporophores were found on
the north slope of the hill, again with the characteristic strands, and
connected with a red oak.

T had to leave Ann Arbor at this time, and not until I came back
in September did I have any further opportunity to make observa-
tions. On October 30 the slope was dug over for a considerable
‘rea around the original habitat of the Cortinarius in question.
The roots of the same maple were found to be hung with the reddish
Strands in all directions, just as luxuriant apparently as in the early
Summer. Here, also, other roots crossing or intertwining with the
maple roots—with one exception—were not affected by the fungus.

212 BOTANICAL GAZETTE [SEPTEMBER,

An ash, basswood, and white oak were examined, but. no trace of
the fungus found. About 272™ from the sugar maple, it was found
that some of the strands were apparently attached to a different
root. Following this up to a clump of red oaks about 54°™ away,
I was again surprised to find that the oak roots in this case were not
connected with the fungus at all, but that the root which was followed’
—which did not have the appearance of an oak root—belonged to
a large Celastrus scandens which wound around one of the oaks. . It
was clear that we had another symbiont connected with the fungus.

DISCUSSION

It may be well here to call attention to the following points which
have been brought out: (a) that Cortinarius rubipes (for so we will
call it) is connected with three forest symbionts belonging to different
families; (6) that it is apparently selective in the sense that the
specific character of the symbiont does not necessarily attract It;
(c) that one of the symbionts is a maple. ie

Noack (12), who has been the only investigator of the agarics
as producers of mycorhiza, thinks he has connected Tricholoma
terreum with both beech and fir, and Lactarius piperatus with beech
and oak. My own observations seem to show that it is undoubtedly
a fact that one fungus may be attached to trees of very different
families. In the case of Celastrus scandens no fruit bodies were
seen, but there can hardly be a doubt that it was the mycelium of
the same species.

It is rather unexpected to find that the same tree species a
exposed to the fungus does not always become associated with it.
It is evident that the mycorhizal fungus may attach itself to ey
different hosts, dependent for its initial attachment on certain env
ronmental factors. :

The maples of Europe are reported as seldom forming mycorhiza
(2). The roots of the sugar maple mentioned above were carefully
examined with a lens, and also under the microscope, and mycor ie
seemed to be everywhere abundant on the smaller rootlets. How
generally they occur on our maples is not known, as hardly any work
has been done in this line in our country.

With regard to the kind of mycorhiza involved, there is of coufs®

‘Ig06} KAUFFMAN—A MYCORHIZA-PRODUCING FUNGUS 213

no uncertainty. Some of the strands and the connected rootlets were
fixed and imbedded, and sections were made to determine the more
intimate relations of the two organs. When stained rather deeply
by fuchsin and gentian-violet the connection could be easily made
out. It is clearly a true ectotrophic mycorhiza. There is a close-
lying layer of parallel hyphae which surrounds the rootlet, and,-in all
but the youngest rootlets, branches of this layer penetrate the root
and form a close intercellular tissue exactly as figured by FRANK (13).
The cells of the root at this time seem to contain little protoplasm
and occasionally hyphal threads are seen to cross the cells of the
cortical layer farther in. In the youngest roots no intercellular
tissue appears to be present.

It would seem that there must be some close physiological rela-
tion; FRANK indeed thought he had demonstrated it. At the present
time, however, nothing definite is agreed upon. To attempt in
Some measure to solve this question, experiments are now under way
With the mycelium of the above-mentioned mushroom. One fact
may have some bearing on the problem; the species of the genus
Cortinarius develop relatively slowly. The writer has never been
able to bring buttons into the house and develop them there, as is
possible with Amanitas and Volvaria. For some reason they seem
to have lost the vigor necessary to this end. It may be that the
explanation of this is found in that a part of their food supply is cut
off, and that the tree really supplies some of the necessaries for the
full development of the sporophore.

Let it not be supposed that all Cortinarii are mycorhiza-formers,
at least normally. Cortinarius armillatus, for example, although
very partial to Tsuga canadensis, is usually found among rotten
logs or leaf-mold near this tree, and is probably a saprophyte; on
the other hand, it has been found growing out of a cleft at the base of
One of these hemlock trees. It seems quite likely, however, that a
good many Cortinarii are in symbiotic connection in the manner of
the one described in this paper. During several seasons’ observations,
T have found C. squammulosus, C. bolaris, and C. cinnabarinus again
and again in places which would indicate some relation to one kind
of tree. C. cinnabarinus seems to prefer the oak, the other two the
beech. Noack (12) has shown the connection of Cortinarius callisteus

214 BOTANICAL GAZETTE [SEPTEMBER

with the beech, C. caerulescens with the beech, and C. julmineus with
the oak. Others will no doubt be added to the list as soon as
observers enter this interesting field.

bt

UNIVERSITY OF MicHIGAN, ANN ARBOR.

LITERATURE CITED.

. Macpoveat, D. T., Symbiotic saprophytism. Annals of Botany 13:1.1899-

2. Stan, E., Der Sinn der Mycorhizenbildung. Jahrb. Wiss. Bot. 34:539-

nA nr w

ee

©

a
N

1900.
. TuBeur, K., Beitrige zur Mycorhizafrage. Naturwiss. Zeitsch. Land.

Sonteies 1: Feb. Le
Hittner, L. , Beitrage der Mycorhizafrage. Idem 1:Jan. 1

993:
. Métrer, P. E., Uber das Verhiltniss der Bergkiefer zur Fichte in den

Jutlandischen Heideculturen. Idem 1r:Aug. & Oct. 1

. HELLRIEGEL H. & Wirrarts H., Untersuchungen iiber aie “Stickstoflernah-

rung. Ber. Deutsch. Bot. Gesells. '7:138 and footnote. 1889.
Nosse & Hitrner, Die endotrophe Mycorhiza von Podocarpus und ihre
physiologische Bedeutung. Landwirts. Versuchsst. 51. 1899

. Arxinson, G. F., Contribution to the biology of the organism causing

leguminous tubercles. Bot. Gaz. 18:157, 226, 257. 1893; and litera
ture quoted.

. SHIBATA, K., Se Studien iiber die Endotrophen Mycorhizen.

Jahrb. Wiss. Bot. 37:6

1g02.
. Worontn, M., Uber fie Pilzwuel von B. Frank. Ber. Deutsch. Bot.

Gesells. 3:205. 188

5:
. Rees, M., Uber Elaphomyces und sonstige Wurzelpilze. . Ber. Deutsch..
1885.

Bot. Gesells. 3:294. A
—— Uber den Parasitismus von Elaphomyces granulatus. Bot. Zelt-

38: 729. 1880. :
. Noack, Uber Mycorhizenbildende Pilze. Bot. Zeit. 4'7:389. 1889.
E>:

RANK, B., Ber. Deutsch. Bot. Gesells. 3: pl. ro.
KaurrMan, C. H., Bull. Torr. Bot. Club 32: 301. 1905.

A NEW FUNGUS OF EGONOMIC IMPORTANCE.
Ratpu E. SMitH AND ELIZABETH H. SMITH.
(WITH THREE FIGURES)

AMONG the subjects of investigation by the California Agricul-
tural Experiment Station, that of a destructive rotting of lemons
Occurring in southern California is one of the most important.
The cause and means of control of this rot have been a complete
mystery to the handlers of lemons, and the fact that the trouble has
been found to be due to a fungus representing not only a new species,
but a well-defined new genus, makes the case one of peculiar interest.

The rot in question has been called the “brown rot,” distinguish-
ing it from the “blue mould,” or Penicillium rot, the commonest
form of Citrus decay. The latter has been known since time imme-
morial, but with the best class of lemon shippers is not usually a great
pest. Lemons affected by Penicillium are almost invariably those
which have become bruised in handling or subjected to improper
conditions. With fruit properly handled, cases of blue mould are
only occasional, In these the affected lemon decays and becomes
covered with the dusty fungus, finally collapsing into a slimy mass,
without infecting the other fruit, even though they be covered with
the spores, A Penicillium-affected lemon in the midst of a box
does not usually infect the other fruit about it in the least when
Proper conditions are maintained.

Within the past few years a new and much more serious form
of Tot has been detected by the lemon growers and shippers. In
lemons which had been picked, washed, and stored for curing, it
Was found that a rot ‘developed which spread rapidly by contact
through the fruit, soon involving the entire box if left undisturbed.
4 @ppearance the affected lemons are characteristic and easily
distinguished from those affected by blue mould, though the latter
Pei follows rapidly on the other and soon covers the decaying
nase - Particularly characteristic is the odor of lemons affected by

wn rot, a peculiar rancid smell by which an experienced person
can detect one affected lemon in a large amount of fruit. This
415] Botanical Gazette, vol. 42[

216 BOTANICAL GAZETTE [SEPTEMBER

odor has, in fact, come to be the infallible test for brown rot in the
lemon curing houses, readily distinguishing the trouble from all
other forms of decay. The rapid spread in the box by contact,
and the appearance of affected fruit, are also very characteristic,
though the latter is soon disguised by Penicillium, and the former
feature is even more true with a rot caused by Sclerotinia.

When brown rot first appeared in the packing houses, search
was made in the orchard to locate the origin of the trouble, with the
result that even upon the tree affected lemons could be found. This
was only the case during the wet season, which, in fact, is the only
time when the rot is troublesome.

It is not the purpose of the present article to describe this trouble
at length, but simply to place on record a description of the fungus
and sufficient characterization of its effects to serve to identify this
form of lemon decay. Lemons affected on the tree show a brownish,
discolored area on the side or end, free from any mould or appear
ance of fungus, and without any decided softening of the rind, but
gradually spreading and soon involving the whole lemon. The
fruit keeps its size, shape, and solidity, even when totally affected,
before which time it usually drops to the ground. The orchard
occurrence is not generally abundant except in wet, warm spring
weather or under like conditions. Affected lemons have 4 peculiar
characteristic odor, and are readily identified by one familiar with
the disease.

Lemons are usually picked quite green, washed in a machine
consisting of a tank of water with revolving brushes, and then stored
in boxes for several weeks to cure. At times of abundant prev®
lence of rot, great loss is experienced in such stored fruit. In get
apparently sound when put away, affected spots develop 0? indi-
viduals here and there in the boxes. These are soon involved,
and also all those which lie in contact with them. These 2g"
spread the trouble, and an extremely virulent decay results. Lemons
affected in this way have the appearance above described, except
that a rather delicate, white mycelium develops on the surface and
grows from lemon to lemon, causing the contact infection. The
trouble never spreads in the mass of stored fruit except by actual
contact of the healthy lemon with an affected spot. When 4 large

1906] SMITH—A NEW FUNGUS 217

amount of fruit becomes affected the characteristic odor is very
pronounced, Penicillium follows rapidly and covers the affected
lemons,

With reference particularly to the cause of the trouble, the fungus,
which comes out on affected fruit in moist air and spreads from

consists of a sterile mycelium, composed of large
mostly continuous filaments. If an affected lemon be
ch Water for several hours, this mycelium develops more
tee upon the surface, forming a slimy, Saprolegnia-like growth.

Negus quickly reaches the fibrous core of the lemon, bits of

which soaked in water are soon surrounded with a luxuriant growth

218 BOTANICAL GAZETTE [SEPTEMBER

On dry or simply moist media (gelatin, bread, etc.) little or no
growth can be obtained. In dilute prune juice the fungus grows

Fic. 2.—Mycelium with sporangia, from moist soil.

with extreme vigor, form-
ing a luxuriant mycelium
of very large, branching,
continuous filaments
(fig. 1). Such growths
are entirely sterile or
nearly so. Occasionally
there are produced a few
large, ovate, terminal
conidia or sporangia, of
the phycomycete type,
which germinate directly
in water or form swarm-
spores. Numerous cul-
tures in various liquid
media have developed
nothing but the mycel-
jum and occasionalspores
of this kind. This fun-
gus is nearly sterile under
such conditions, and en-

-tirely so on affecte

lemons in the air, though
with extreme vegetative
vigor. Cultures of pieces
of affected lemon in pure
water, kept for a long
time, usually develop
nothing but mycelium,
though occasionally
conidia or sporangia are

roduced to some extent.
Bits of this sterile ™Y

° ce
celium placed on’ sound lemons in a moist chamber See
infection and characteristic rot, Lemons soaked in water, 9

1906] SMITH—A NEW FUNGUS 219

which a sterile culture of the fungus has been mixed, also become
infected,
Affected lemons placed on moist soil (as in nature by falling
from the tree) produce a visible mycelium upon the surface and make
such ground highly infectious to sound fruit laid upon the surface.
In soil thus inoculated the characteristic spore stage of the fungus
has been found. This is also readily produced on wet filter paper

Fic. 3.—Stages in development of swarmspores from sporangia.

in the bottom of a moist chamber containing an affected lemon.
Upon an extremely delicate, fine, septate, branching mycelium,
very numerous, terminal sporangia are produced (fig. 2), much as
in Pythium under similar conditions. These sporangia differ,
however, from’ those of the latter genus, in producing swarmspores
by direct internal division, behaving in this respect like those of
Phytophthora, which they also resemble in appearance (fig. 3).
The appended description gives further details. These swarm-

220 BOTANICAL GAZETTE [SEPTEMBER

spores are extremely infectious to sound, green fruit in all stages
of development.

Lemons on the tree become infected during the rainy winter and
spring months, almost entirely on the lower part of the trees (which
are allowed to branch close to the ground), and in the wettest part
of the orchard. The fungus at all times shows a very decided
moisture requirement for its development. Infection takes place
by swarmspores from the soil, both on the tree and in the washing
tank, in the latter case by the orchard dirt, dust, leaves, and other
sediment which accumulates in the water.

The writers have given much consideration to the generic rela-
tions of this fungus, particularly as to whether it is sufficiently dis-
tinct from Pythium and from Dr Bary’s Pythiopsis. It is remark-
able for the connection which it presents between the Phycomycetes
of this nature. While similar to Pythium in habit, except as to
its peculiar parasitism on the lemon, this species is definitely excluded
from that genus by its internal formation of swarmspores. We
have felt considerable hesitancy in separating this form from Pythi-
opsis, on account of the similarity in swarmspore formation; the
latter, however, being founded on a species of such different habit,
an entomophthorous form of the Saprolegnieae, and being prac
tically unknown save from the original description, we feel justified
in proposing a new genus for our species. It is particularly of
interest as being more exactly intermediate between the Sapro
legnieae and Peronosporeae than either Pythium or Pythiops's,
and also forming a close transition from Pythium to Phytophthora,
having the swarmspore formation and something of the parasitic
tendency of the latter. In brief, Pythiacystis has the soil habit
of Pythium, the aquatic habit of the same and of the Saproleg:
nieae (including Pythiopsis) except for its usual sterility under
such conditions, the sporangia formation of Pythium, the swat
spore formation of Pythiopsis and Phytophthora, and parasitic
activity intermediate between Pythium and Phytophthora.

No indication of sexual reproduction has been observed
large amount of material and numerous cultures examined.

An Experiment Station bulletin on the nature and control of
this fungus will be issued in due time.

in the

1906] SMITH—A NEW FUNGUS 221

Pythiacystis Smith & Smith, n. gen.

Parasitic on living plants, or saprophytic with abundant moisture.
Fertile mycelium delicate, septate, with numerous, terminal, sym-
podially developed sporangia. Aquatic mycelium typically sterile,
with occasional conidia or sporangia. Filaments very large and
vigorous, continuous, much branched.

Sporangia typically rounded or ovate, dividing internally into
biciliate swarmspores which immediately become motile and emerge
from a terminal opening,

Conidia similar to sporangia, germinating directly by a germ
tube.

Sexual reproduction not observed.

Differs from Pythium in mode of swarmspore formation, and from Pythiopsis
in habit. Closely intermediate between Saprolegnieae and Peronosporeae.

Pythiacystis citrophthora Smith & Sm’ 4, n. sp.—Parasitic on
lemons, and occasionally other Citrus fruits, .ausing decay of green
fruit on the tree and in the storehouse. Mycelium in affected
fruit sterile, inhabiting rind and fibrous portions. Internal, except
in moist air, Mycelium in water or nutrient liquids very vigorous,
usually sterile, or occasionally with conidia or sporangia. Fruiting
Stage found typically in moist soil, in contact with affected fruit.
Sporangia ovate or lemon-shaped, sometimes rounded, considerably
elongated, or double, with terminal protuberance; 20X30 to 60
X90H, AV. 35X50 4. Produced in great abundance under favorable
conditions, In water dividing quickly by internal division into
5 to 40 (usually about 30) swarmspores, which are immediately
set free and discharged through a terminal pore.

Swarmspores 10 to 16 w in diameter, at first elongated, becoming
rounded ; with two lateral cilia 30 to 40m in length, Actively
motile when discharged, soon coming to rest and germinating.

Fungus abundant in winter and spring in southern California lemon orchards
and packing houses, causing serious losses.

UNtverstry oF CALIFORNIA, BERKELEY.

Bonin} OLEERATURE.
BOOK REVIEWS.
American fossil cycads.*

SINCE 1898 Dr. WIELAND has been investigating the wonderful American
display of fossil cycadean forms, usually referred to now as the Bennettitales.
The investigation has demanded an unusual amount of patience and hard work
in making the necessary collections and sections. The student of living plants
has no adequate conception of the labor involved in obtaining valuable results
from sectioning fossil material. The result of all this work now appears m .

ulky memoir published by the Carnegie Institution. It is a veritable mine of
information in reference to Bennettitales, a mine that will be worked by botan-
ists for a long time to come. To present the results here would be to write
another book. They are not essentially new, but they are so much more com-
plete and more finely illustrated than ever before that the student of gymno-
sperms must always consult this volume. ‘

The contents may be outlined by giving the chapter headings as follows:
discoveries and collections, preservation and external characters, on the methods
of section cutting, trunk structure, foliage, ovulate cones, bisporangiate -
young fructifications, existing and fossil cycads* compared, fern ancestry 4m
angiosperm analogies.

The author is to be congratulated upon the amount of good work t
accomplished and upon the fine and permanent form in which it has ap
Morphologists can now lay hold of this material as they never could before,
organize it for general use.—J. M. C. ”

MINOR NOTICES.

Reproduction.—Under the title “multiplication and sexuality in p
KtstEr’ has published some expanded lectures which were given 1D anu
and February of this year and constituted ‘‘an advance course for east
Vegetative multiplication is first considered in the higher plants, then ™ pi
lower. Sexual reproduction is treated historically, and then taken uP from ' =m
standpoint of its evolution, the lower forms being treated first. The gene

ne-
problems discussed are: sexual affinity, hybridization, polyspermy, eee
and

hat he has

and

”
ants,

sis, apogamy, apospory, and distribution of sexes. ‘The book closes W? h
on theories of reproduction and sexuality. It is a convenient, compact,
reliable compendium of the subject—CHartEs J. CHAMBERLAIN.
t WIELAND, G. R., American fossil cycads. pp. 296. pls. 50- figs. 138. Oe
Institution. 1906. —
2 Kister, Ernst, Vermehrung und Sexualitit bei den Pflanzen. 8vo.
figs. 38. Leipzig: B. C. Teubner. 1906.

222

p. vit 12%

1906] CURRENT LITERATURE 223

Leaflets on Philippine botany.—Under this title A. D. E. ELMER proposes
to issue in serial form articles on Philippine plants, both scientific and economic,
printed in English, Latin, German, or French. This publication will appear at
irregular intervals, at a subscription price of 1? cents per page, and may be obtained
by addressing the editor at Manila. The first issue is a paper of 41 pages entitled
Philippine Rubiaceae, by the editor, containing 150 species, of which 45 are new,
representing 42 genera.—J. M. C.

Das Pflanzenreich.*— Part 26 contains the Droseraceae by L. Diets. Dro-
sophyllum, Dionaea, and Aldrovanda are regarded as monotypic genera; while
Drosera is credited with 84 species, 5 of which are new. A very full discussion
of structure and range precedes the synopsis—J. M. C

Pflanzenfamilien.s—Part 224 includes the completion of the Spiridentaceae,
the Lepyrodontaceae, and the Pleurophascaceae, and a portion of the Necke-
raceae, all by V. F. Brorwervus. Part 225 continues the Ascolichenes by A.
ZAHLBRUCKNER.—J. M. C. :

NOTES. FOR STUDENTS.

contents of a Vaucheria filament, but later found that it was possible to observe
the contents in situ. He saw the ultramicroscopic particles of plasma and
chlorophyll, the former white and blue, the latter red and green—colors whose
significance is unknown as yet for lack of sufficient physical investigation of
the instrument. He watched the collision of plasma particles with structureless
oil drops and their recoil, and the like collisions of chlorophyll particles and
their disappearance in the oil, in which the number of red and green chlorophyll
Sranules steadily increased. This appears to be actually the formation of a
colloidal solution of chlorophyll in oil—an oleosol.

or stellate flecks of chlorophyll particles are distributed through the stroma,
OBE. Structure is like that of the protoplasm; there is no indication of the
Uticn of chlorophyll in oil droplets lying in the stroma—a widely accepted
ion,

SEnciER, A., Das Pflanzenreich. 26 Heft. Droseraceae von L. Drets. pp-
730. figs. 40 (286), map 1. Leipzig: Wilhelm Engelmann. 1906. M 6.80.

4 ENGLER, A. und Prantt, K., Die natiirlichen Pflanzenfamilien. Lieferungen
224 and 225. Leipzig: Wilhelm Engelmann. 1906.
. §GarpuxKov, N., Untersuchungen mit Hilfe des Ultramikroskopes nach Seiden-
topf. Ber. Deutsch. Bot. Gesells. 24:107-112, 155-157. 1906.

224 BOTANICAL GAZETTE [SEPTEMBER

The nucleus of Tradescantia appears to have a structure like protoplasm,
but much more compact.

Bending movements of Oscillaria are accompanied by wave-like movements
of particles in the cells; and the longitudinal movements by a streaming of par-
ticles on the surface in a direction opposite to that of the motion of the filament.
These particles pass off into the water when they reach the end of the filament.

Ultramicroscopic organisms in figure-of-8 forms, and colonies in form like
certain flagellates, similar to the organisms already described by RAE HLMANN,

to be, but is probably initiated by a complex motion of the siren
particles (ultramicrons) of the protoplasm, whose structure seems identi
with that of colloidal solutions as determined by ZsicMonpy with the instrument.
The first movement, indeed, may be what has long been known as the Brownian
movement, once so carefully distinguished from the ‘‘vital’? ones as “purely
physical.”

In plasmolysis GatpuKov has seen the protoplasmic particles move from
the periphery toward the center of the cell, changing shape at the same time
from round to vermicular, while in the chloroplast simultaneously the vermicular
chlorophyll particles creep out upon the surface. In Flagellatae there is :
vigorous movement of particles in the ‘em of the cilia and’ below the mout
opening, before the gross movements begi .

Whereas in chlorophyllose cells ms cell wall i is optically empty (leer), i
one to see the cell contents clearly, the wall of bacteria and fungi has so scr
a structure that nothing can be seen through it. Yet the purple bacteria pine
also work photosynthesis have a wall optically empty. These facts are we ce
to be related to the necessity for transparence to light in photosynthetic cells.
[Bae ae | 8

Araucarieae.—A. C. Sewarp and Srpitte O. Forp have published vad
results of a study of the Araucarieae.© The two living genera representine
the group, Agathis and Araucaria, have long stood somewhat stiflly apart
other Coniferales, not only on account of the known facts in reference t re
but chiefly, perhaps, on account of lack of knowledge. The authors mee
shalled our knowledge of extinct and living forms in this memoir; and us
opinions may differ as to their conclusions, there can be only one opinion 4 as
the value of the work. The subject is presented under ms following © cal
distribution, generic diagnosis, seedlings, stem anatomy, roots, leaves, ”
traces, reproductive shoots, fossil Araucarieae, and phylogenetic consider but
and conclusion, The details are too numerous to be included in 4 a reviews
the conclusions are too important to be passed over lightly.

xtinct
6 Sewarp, A. C. and Forp, SrsttiE, O., The Araucarieae, recent _
Phil. Trans. Roy. Soc. London. B. 198 : 305-411. pls. 23-24. figs- 28. 1900.

1906] CURRENT LITERATURE 225

In general, the memoir is a contention that the recent brilliant work which
has knit together cycads and Filicales has developed the too sweeping conclusion
that all gymnosperms have the same phylogenetic connection; that the old view
suggesting a connection between conifers and lycopods deserves more attention
than it has been receiving; and that at least the Araucarieae strongly suggest
a lycopod origin. It is urged upon paleobotanical evidence that the Arauca-
rieae are the most primitive of Coniferales, certainly more primitive than the
Abietineae; and that this testimony from history is supported by numerous
evidences of relatively primitive structures still exhibited by Agathis and Arau-
caria. The difficult question of the Cordaitales, which seem to combine char-
acters of Cycadales and Coniferales and so necessitate a common phylogeny,
is disposed of by minimizing their resemblances to the latter, at least to the
Araucarieae. It must be remarked that the authors repeatedly emphasize the
fact that they are dealing only with the Araucarieae, and that it does not affect
their main contention whether the other Coniferales are related to a filicinean
ancestry through the Cordaitales or not. In developing the differences between
the Araucarieae and other Coniferales, they have been so impressed by their
importance that they have suggested a group Arawucariales, coordinate with
Coniferales, Cycadales, etc. For this group, at least, they claim a lycopo
ancestry, through some such form as Lepidocarpon, emphasizing the seed-like
sporangia recently described by Scort in that genus.

The authors are to be congratulated upon a very fair statement of their
case, a statement which dodges none of the difficulties, and which really does not
claim very much more than that an almost abandoned hypothesis must not be
neglected.

A very interesting appendix to this memoir may be obtained by reading the
report’? of two recent meetings of the Linnean Society, at which various views
as to the origin of gymnosperms were presented and combated by English
students of the group.—J. M. C.

Items of taxonomic interest.—N. L. Britron (Bull. N. Y. Bot. Gard.
4°115-127, 137-143. 1906) describes new species of Bahama plants under
Coccolobis, Caesalpinia, Canavalia, Hibiscus, Heliotropium (2), Lantana (2),

estrum, Stemmodontia, Anastraphia, Marsilea, Dondia, Cassia, Maytenus, My-
roxylon, Opuntia, Limnanthemum, Metastelma, Aster—W. H. BLANCHARD (Tor-
reya 6:147-149. 1906) has described 2 new species of Rubus (dewberries) from
New England—H. D. House (idem 150) has described a new Convolvul
from Georgia—H. A. GLEASON (Bull. Torr. Bot. Club 33:387-396. 1906)
has revised the pedunculate species of Trillium, defining 19 species, 3 of which
are new.—H. D. House (Rhodora 8:117-122. 1906) has described the violets
and violet hybrids of the District of Columbia and vicinity, recognizing 26 species,
and describing 8 new hybrids.—M. L. FERNALD (idem 126-130) has described
new species of Cyperus (2) and Eleocharis from Eastern North America.

7 New Phytol. 5:68-76, 141-148. 1906.

226 BOTANICAL GAZETTE [SEPTEMBER

—E. B. Copetanp (Philippine Jour. Sci. 1:143-166. pls. 28. 1906) has described
47 new species and 2 new genera (Acrosorus and Thayeria) of Philippine ferns.
—SPENCER LE M. Moore (Jour. Botany 44:217-224. 1906) has described 2 new
genera of Acanthaceae from Madagascar, Melittacanthus and Amphiestes.—BUNz0
Hayata (Jour. Linn. Soc. Bot. 37:330. pl. 16. 1906) has described a new
genus (Taiwania) of conifers from the Island of Formosa, belonging to the
Taxodieae and nearest to Cunninghamia.—Epira M. Farr (Ottawa Nat.
20:105-111. 1906) has described new species from the Canadian Rockies and
Selkirks under Pachystima (4), Arnica, Hieracium, Dryas, and Ranunculus.—

. Starr (Kew Bulletin 1906 : 204) has published a new genus (Diandrolyra) of
grasses whose native country is unknown.— O. E. Jenntncs (Annals Carnegie
Mus. 3 : 480-485. 1906) has published new species under Kneiffia and Tbidium
(Spiranthes) from Pennsylvania—V. F. BrorHerus (Hedwigia 45 :271- 1906)
has described a new genus (Uleobryum) of Pottiaceae from Peru.—F. LAMSON~
ScriBNER (Rhodora 8 : 137-146. 1906) has included in a newly named genus
(Sphenopholis) the grasses that have been referred for many years to Eatonia
Raf., recognizing 7 species —W. H. BLANCHARD (idem 146-157) has described 5
new blackberries (Rubus) from Maine.—R. SCHLECHTER (Engler’s Bot. Jahrb.
38 : 137-143. 1906) has described two new African genera (A frothismia and
Oxygyne) of Burmanniaceae—J. C. AnTHuR and F. D. Kern (Bull. Torr. Bot.
Club 33 : 403-438. 1906), in a revision of the N. Am. species of Peridermium,

f

Japanese Experiment Station Bulletin.—A new departure in experiment
station publications had been inaugurated by Professor HozaI of the Imperial
Central Agricultural Experiment Station of ‘Tokio. In order to make the results
of work carried on in the experiment stations of Japan accessible to investigators
of other countries, a periodical Bulletin will be issued in which all work that
may be of general interest will be published. The experimental system of Japan
comprises 47 stations, whose work will in large part become available to the world
through the publication of this Bulletin, printed partly in English and partly
in German. The first number® contains 11 articles, some of which are briefly
noted here to show the scope of the publication. S. Macnrtpa reports ‘
influence of dilute solutions (0.3%) of Ca and Mg salts on the putrefactive
action of bacteria. The rate of putrefaction was determined by the quantity
of NH, formed in urine and in-pepton solutions to which the salts had been
added. It was found that the Ca-salts retard putrefaction, while Mg
favor the process.

Several articles of agronomic interest are given by G. DAIKUH.
correction of an unfavorable ratio of lime to magnesia, also on the lime factor

ARA on the

8 The Bulletin of the Imperial Central Agricultural Experiment Station, Jap"™
Vol. I. No. 1. pp. 94. pls. 13. Nishigahara, Tokio. December 1995.

*

1906] CURRENT LITERATURE 227

for the tobacco plant, and on the application of magnesia in the form of mag-
nesium sulfate for the rice plant. UvyEDA gives an extended account of a new
phytopathological bacterium (Bacillus Nicotianae) which produces a serious

isease known as stem-rot and black-leg of tobacco. Horr gives an account
of a smut on the cultivated bamboo. The fungus attacks the young internodes
of growing branches, and as it may infect these at any time during the growing
season, whole forests of bamboo often become infected. As the bamboo fur-
nishes material for building as well as for household utensils and fences, the
damage thus caused is considerable. The fungus is referred to Ustilago Shir-
aiana P. Henn.—H. HassE.srine.

Respiratory enzymes.—PALLADIN announces his adherence to the theory
of Bacn and Cuopat, that normal respiration depends upon the presence of
x) oxidizable substance and 2) two enzymes, whose mixture was formerly desig-
nated oxidase, @) oxygenase, which has, attached to various radicals, the char-
acteristic peroxid or hydroperoxid group O'O or O'OH and serves to transfer
O., and b) peroxydase, which is a catalyser and renders active the oxygenase.
When oxidative processes do not occur it is because one or two of the three are
wanting. The less stable oxygenases, and those which with water quickly become
hydroperoxids, are used up promptly, giving rise to some of the respiratory
CO.; so that often tests do not show any “oxidase” present in plant parts;
but the peroxidases, which are very stable, can always be foun

rom his researches PaLLaptn concludes? that the cieeiionie of one or
the other enzyme is connected with the stage of development of the plant. For
anaerobic respiration prevails in embryonal organs and in lower plants, which
alone are capable of anaerobic life. In the embryonal stage oxygenase is at a
minimum, increasing with the passage into active life, and diminishing in organs
which have ceased to gr

Miss PRIS ahi '© working under PALLADIN’s direction, finds in frozen
onions and their sap no oxygenase, but xydases whose quantity increases
with respiratory activity, if H.O. be siotied ee continues to do so even when
respiration falls. Katalase, however, is present in the sap after the freezing.

These researches are more and more justifying the opinion that the origin of

Somer lt CO, is very complex, and that more than one catalyser is taking
n the dissociation.—C. B

Ancient history of ferns.—ArBER* has tech together the recent develop-

ment of knowledge in reference to the history of ferns in a short paper that brings

9 PALLADIN, W., Bildung der verschiedenen Atmungsenzyme in Abhangigkeit

oe Entwicklungstadium des Pflanzen. Ber. Deutsch. Bot. Gesells. 24:97-107.

Igo

pie to cae Bo T., Bildung der ae in verletzten Zwiebeln von
tum Cepa. Ber. Deutsch. Bot. Gesells. 24:134-141. 1906.

ARBER, E. A. ae On the past history of pee Annals of Botany 20:
215-2 a2. 1906.

228 BOTANICAL GAZETTE [SEPTEMBER

the important facts well in view, however opinions may differ as to some of the
conclusions. It is shown that the fern-like Cycadofilices, later called Pterido-
sperms, were a dominant group of the Carboniferous; but that the evidence for
the existence of ferns in the modern sense is at present very uncertain. For
any Carboniferous fern-like plants that may prove to be true ferns the author
suggests the name Primofilices, since to distinguish among them definite euspor-
angiate and leptosporangiate habits is impossible. In fact, all the so-called
“*fructifications” of Paleozoic ‘“‘marattiaceous ferns’? may prove to be the
microsporangiate structures of Pteridosperms. Until this is determined, the
existence of eusporangiate ferns in the Paleozoic as a dominant group must
remain uncertain. This also means that the old question as to whether the
eusporangiate or the leptosporangiate type of ferns is the more primitive has
lost its apparently sure answer from history. In fact, while the author gets
sure evidence of leptosporangiate ferns in the Permian, he does not find similar
satisfactory evidence of eusporangiate ferns until the Tertiary; although in both
cases he recognizes the possible Paleozoic occurrence. As to the water ferns,
the evidence of their existence does not become clear until the Tertiary. The
claims for them in the Paleozoic are so much in conflict with all morphological
testimony that they have never seemed to be very serious. The general con-
clusion in reference to the ferns seems to be that while Pteridosperms are @
dominant group in the Paleozoic; and the Cycadophyta are one of the dominating
groups of the Mesozoic; there is no evidence at present of the dominance of ag
fern group except that of the leptosporangiates in the Mesozoic and continuing
into the present flora.—J. M. C.

natans, and of Lewis" on R. crystallina. The spore mother cells are at first
separated by extremely delicate membranes in which no cellulose could be wee
onstrated, and upon them secundary and tertiary thickening layers are deposite

No nutri-
-nucleated
nsistS

bridging the space between the priinary wall and the tertiary layer.

tive material was found between the isolated mother cells, and no non

reticular resting nucleus was found. The large deep-staining nucleolus ©

of a number of deeply chromatic granules embedded in a faintly staining — :

A long and well-marked spirem thread occurs in the prophase of eae!

of the mother cell. The reduced number of chromosomes is 7 oF 8: oii
12 BEER, RupotF, On the development of the spores of Riccia glauca- el

of Botany 20:275~291. pls. 21-22. 1906.

?3 Bot. GAZETTE 37:161-177. 1904.

14 Bot. GAZETTE 41: 109-138. 1906.

1906] CURRENT LITERATURE 229

phase a nuinber of chromatic bodies (presumably derivatives of the chromo-
somes) are distributed on the linin fibers, and subsequently aggregate to form
the lobular nucleolus of the resting nucleus. The first spore wall is cuticularized

of three regions. The endospore (pectose and cellulose) is formed late, and
is often separated from the second wall by a thin band of dark material.—J. M. C.

Postelsia.'S—-Four years ago the first volume under this title appeared,"
containing seven papers by members of the Minnesota Seaside Station on the
coast of Vancouver. The present volume is printed in the same handsome
Style, and also contains seven papers as follows: Observations on plant distri-
bution in Renfrew district of Vancouver Island (pp. 1-132. pls. rrr), by C. OQ.
RosENDAHL; The Conifers of Vancouver Island (pp. 133-212. pls. 12-15), by
F. K. Burrers; Hepaticae of Vancouver Island (pp. 213-235), by ALEXANDER
W. Evans; Some western Helvellineae (pp. 236-244), by D. S. Hone; Ren-
frewia parvula, a new kelp from Vancouver Island (pp. 245-274. pls. 16-19),
by Rogert F. Griccs ; A study of the tide-pools on the west coast of Vancouver
Island (Pp. 275-304, pls. 20-25), by IsABEL HENKEL; Some geological features
of the Minnesota Seaside Station (pp. 305-347. pls. 26-33), by C. W. Hatt.

The paper on plant distribution reaches the conclusion that the pterido-
Phytes are poor in species for so moist a region, that the gymnosperms constitute
the great mass of the vegetation, and that the monocotyledons are more impor-
tant than the dicotyledons. The paper on conifers contains very interesting
observations, treats Picea, Tsuga, and Pseudotsuga as sections under Abies,
and organizes a key to the northwestern genera on the basis of foliage. Ren-
jrewia is a new genus of kelps nearest to Laminaria and Cymathere.—J. M. C.

Synapsis and reduction.—From a study of the pollen mother cells of Acer
platanoides, Salomonia biflora, Ginkgo biloba, and Botrychium obliquum Car-
DIFF draws the following conclusions.*7 Synapsis is a constant morphological
character of the mother cell, and the unilateral position of the synaptic knot is
Probably due to gravity. Previous to synapsis the chromatin is in two or more
threads which arrange themselves in pairs, longitudinally, and finally fuse during
Synapsis, but there is not a complete mingling of chromatin substance in the
chromatic thread. The thread splits longitudinally in the first mitosis, probably
along the line of previous fusion. The chromosomes are of different sizes and
do not behave alike at the first mitosis.

Te .
a The year book of the Minnesota Seaside Station. 1906.. pp- 364. pls. 33.
ned from Josephine E, Tilden, Univ. Minn., Minneapolis. $2.25.

'© Bor. Gazette 34:468. 1902. :

Carpirr, I. D., A study of reduction and synapsis. Bull. Torr. Bot. Club
33'271-306. pis. 12-15. 1906.

230 BOTANICAL GAZETTE [SEPTEMBER

It is probable that at fertilization there is a nuclear but not a chromatin
fusion, and that the paternal and maternal chromatin retain their identity through-
out the sporophytic phase, finally fusing, in so far as they fuse at all, during
synapsis. If this be true, the two important phenomena of fertilization—stim-
ulus to growth and intermingling of ancestral characters—are widely separated,
the stimulus to growth occurring when the nuclei fuse, and the mingling of
characters being delayed until synapsis—CHARLES J. CHAMBERLAIN.

Nutrition of the gymnosperm egg.—Miss Stopes and Fuyu*® have been
investigating the nutritive relations of the surrounding tissues to the egg in gym-
nosperms. As is well known, about the “central cell,” and later about the egg,
there is organized usually a very distinct jacket of nutritive cells, whose inner
walls are conspicuously thickened and pitted. The authors find that the delicate
walls of the endosperm cells are pitted in the same way; and that the large pits of
the jacket cell-walls are closed by a membrane perforated only by plasmodes-
men. This latter fact is the most interesting one of the paper, for it precludes
the old notion of nuclear migration or of any transfer of solid material from
the jacket cells to the egg. The jacket cells are regarded as glandular, secreting
substances for the digestion of the starch and proteid granules stored in the endo-
sperm. The statement is made in the summary that the jacket cells “are
considered the phylogenetic homologues of the angiospermic antipodals,” @
statement evidently based upon their similar function —J. M. C.

Ecological survey of Northern Michigan.—Under the direction of C. C-
Apams there has been published"? the report of an ecological survey conducted
by the University Museum of the University of Michigan in 1904. The regions
selected were Porcupine Mountains in Ontonagon County, on the south
of Lake Superior, and Isle Royale, an island near the Canadian shore. Especially
significant i is the report by A. G. RuTHVEN on the relation of the plants

animals of these regions to their environment. Lines of survey were run @

the region examined, in such a way as to include examples of all the repent
habitats. These habitats were then examined in as much detail as per-
mitted, and special attention was given to the relations of the nae to its
environment. In this study attention was directed particularly to the forces
and conditions composing the environment, in order that the dominant forces
might be clearly recognized. The results are too numerous and detailed me
mention, but the work is unique and extremely suggestive —J. M. C.

Ecology of algae.—FritscH?° has made a statement of some of the problems

8 Stopes, M. C. and Fuju, K., The nutritive relations of the ieee ear
eih. t. Cen pl.t

to the archegonia in gymnosperms. B Bo tralb. 20:1-24- sata
t9 An ecological survey in Northern Michigan. Prepared under the ici
of CHas. C. ApAms. Publ. in Rep. State Geol. Survey for 1905. pp- 133- #85: 27 17”

2° Fritscu, F. E., Problems in aquatic biology, with special reference t0
study of algal periodicity. New Phytol. 5:149-169. 1

1906] CURRENT LITERATURE 237

connected with the study of algal ecology, and has suggested some means towards
their solution. The first problem considered is the determination of what shall
constitute a formation, and the contrast with terrestrial formations is made.
Suggestions are made as to the significant unit and examples are given. Chief
attention, however, is given to algal periodicity, the seasonal: variations of algae
being much greater than those of terrestrial plants. ‘In most cases in an aquatic
flora a number of dominant forms succeed one another in the course of a year,
and after their period of prevalence is past they disappear either suddenly or
gradually.” Periodicity of algae is either seasonal or irregular, and the factors
concerned in both of these cases are discussed. In illustration of his statements,
the author discusses the algal flora of a particular pond. e paper is a distinct
stimulus to the study of pond life in an effective way,—]. M. ©.

Decay of timber.—Following the lines of investigation laid down by Hartic
in his Zersetzungserscheinungen des Holzes, BULLER?" has contributed a further
study on the subject of the decay of timber caused by the higher fungi. The
form studied is the common Polyporus squamosus, which is found on many
Species of broad-leaved trees. Like other forms of this class, the fungus gains
entrance to the tree through wound surfaces. The mycelium progresses more
rapidly in a longitudinal direction in the wood, so that the decayed region extends
many feet up and down the trunk and principal branches, while advancing only
a few inches in a radial direction. The yphae penetrate into all the wood
cells. The decaying wood is lighter in color than the sound wood. In the

sound wood.—H. HassELBRrnc.

Pogamy in Dasylirion.—Went and BLAAuw?”? have described apogamy in
Dasylirion acrotrichum, in the case of plants in cultivation in the Utrecht Botan-
teal Garden. This Mexican species is dioecious, and no staminate plants exist
in the garden, thus precluding the possibility of fertilization. A certain number
of fruits matured sufficiently to attract attention, and an examination of the

development, in some cases completely filling the sac. Dasylirion is thus added
to the very few illustrations of endosperm-formation without fertilization. In
these endosperm-containing sacs no embryos were found, but in some others a
8roup of cells was discovered in the usual position of the egg-apparatus, which
the authors seem justified, judging from the figures, in regarding as a young
embryo. The position would suggest a case of parthenogenesis, but there is room
for doubt, and the authors prefer to speak of it as a case of apogamy.—J. M. C.
Seth ica A. H. Recmatp, The biology of Polyporus squamosus. Huds., a
oying fungus. Jour. Econ. Biol. 1: 101-138. pls. 5-9. 1906.
ou —— F. E..F, - an Biaauw, A. H., A case of apogamy with Dasylirion
m Zucc. Recueil Tray. Bot. Néerland. no. 3. pp. 12. pls. 5. 1905.

232 BOTANICAL GAZETTE [SEPTEMBER

Photosynthesis by carotin.—Kount?3 shows by new experiments that the
secondary maximum in the curve of photosynthesis, as drawn by ENGELMANN,
is due to carotin. He eliminates the possible error in this determination (made
by an improvement of the bacterial method), showing that the bacteria are in no-
wise affected by the F-rays alone. But when algae are illuminated only by rays
absorbed by carotin, the movement of the bacteria begins, indicating evolution
of O.. He also shows that though O, is necessary to the formation of chlorophyll,

in excess, since they can use the O, set free in photosynthesis. Of etiolin Koxt
can find no trace, and he holds it certain that neither carotin nor xanthophyll
(the latter probably a transformation product of the former) can be antecedents
of chlorophyll. Whatever gives rise to it is probably colorless.—C. R. B.

less and less toxic as it approaches the flowering period and finally becomes
entirely harmless. The toxic principle has not yet been determined for these
species, but is probably delphinine and some other related alkaloids. Other
poisonous plants mentioned are species of Zygadenus, Cicuta, Lupinus, and
Hymenoxys. The last plant is not strictly poisonous, but forms after being
eaten a rubbery mass that may prove injurious. The bulletin contains a use
bibliography of the literature of plants poisonous to cattle on the range-~™
Meap WILCox.

Ecology in the Philippines.—It is a matter of no small interest to pee
the first extended ecological study of a region of the Philippines. WHITFORD $
account of the vegetation of the Lamao forest reserve introduces us to 4 tropical
region, where the details of plant ecology are new and fascinating, and . —
the problems must be peculiarly complex. The Lamao forest reserve 15 7 ef,
province of Bataan (Luzon), on the east slope of a group of volcanic peaks know®
as Mount Mariveles. After the introductory statements as to geology and ar
ography, climate, and soil, the vegetation is discussed at length under six soso
tions: Strand, Bambusa-Parkia, Anisoptera-Strombosia, Dipterocarpus-Shore®
Shorea-Plectronia, and Eugenia-Vaccinium. The half-tone plates are numerous
and present most interesting views of tropical vegetation.—J. M. C

t.
23 Kont, F. G., Die assimilatorische Funktion des Karotins. Ber. Deutsch. Bo
Gesells. 24:222-229. 1906. S
ta.
s , 24GLover, G. H., Larkspur and other poisonous plants. Bull. Col. Exp-
113:1-24. pls. 1-8. 1906.
5 WuITForD, H. N., The vegetation of the Lamao forest

2 reserve- Philippiné
Jour. Sci. 1:373-431, 637-679. map and pls. 1-45. 1906.

1906] CURRENT LITERATURE 233

Azotobacter.—Stoxiasa and his assistants have been cultivating <Azoto-
bacter chroococcum and Radiobacter sp. to determine the fixation of nitrogen and
the fermentative respiratory activity.2°° They do not confirm BrtyERINcK’s
assertion that Radiobacter fixes free N, nor that Azotobacter in company there-
with fixes more N than in pure culture. They conceive the fermentation of the
mannits and of glucose by Azotobacter to be wrought by glycolytic enzymes
which split them into lactic, acetic, and formic acids and alcohol. By the decom-
position of these, CO, and Hz are produced, the former at greater rate than in
any organisms previously known. Thus 18™ of Azotobacter, dry weight, pro-
duces on an average 1.38™ CO, in 24 hours. The H, is believed to have an
important réle in the fixation of N—C. R. B

Subalpine scrub in New Zealand.—CocKAYNE”’ has named the distinct zone of
plants on many New Zealand mountains between the limit of the forest and the
subalpine meadow the “subalpine scrub.” On Mount Fyffe this formation
differs from the typical one in the paucity of species and in the great domination
of Cassinia albida, a species peculiar to that locality, in places being almost a
pure formation. Ranunculus lobulatus, another local species, is the principal
plant beneath the scrub. _ Some of the shrubs are strongly xerophytic; and the
author thinks that the amount of xerophylly observed in many New Zealand
plants is by no means a measure of their adaptation to present environment,
but rather a survival from previous more xerophytic conditions.—J. M

Monoecism of Funaria hygrometrica.—BoopLE*® has Seishin to settle
the contradictory statements in reference to the distribution of the male and
female organs of this species. It seems that bryological works describe it as
Monoecious; and that certain general textbooks speak of it as dioecious. It
turns out that the bryologists are right, as might have been expected. ‘The
male axis bears a terminal male flower, and produces a lateral branch (inno-
vation) which forms a terminal female flower. The female branch may be
inserted at different levels, sometimes high up, sometimes basally; it usually

as a tuberous base bearing a tuft of rhizoids, and if torn away appears like an
independent plant.”—J. M. C.

Color of algae.—GatpuKov exposed the blue-green plates of. Phormidium
and the red Porphyra to the spectrum of a strong electric light.2? In ten hours
under all the green to violet rays the color had become yellow to brown-yellow,

TOKLASA, J., et al., Ueber die chemischen Vorginge bei der Assimilation des
Ste Stickstoffes durch Azotobacter und Radiobacter. Ber. Deutsch. Bot.
Gesells. 24:22-32. 1906.

*7 CockaynE, L., Notes on the subalpine scrub of Mount Fyffe. Trans. N. Z.
Inst. 38: 361-374. 1906.

38 Boopieg, L. A., The monoecism of Funaria hygrometrica Sibth. Annals of
Botany 20: 293-299. 1906.

*? GatDuKov, N., Die komplementiire chromatische Adaptation bei Porphyra
und Phormidium. Ber. Deutsch. Bot. Gesells. 24:1-5. 1906.

254 BOTANICAL GAZETTE [SEPTEMBER

remaining blue-green under the red to yellow rays. Porphyra remained red
in the green-violet, but became green in the red-yellow. The pigments thus
become of the complementary color to the incident light, and change in a time
inversely proportional to the intensity of the light. The same change, but much
slower, had been observed by the author in nature, and he considers this com-
plementary chromatic adaptation the chief factor in determining the color of
algae.—C. R. B.

Pollen tubes of Cucurbitaceae.—Kirkwoop*° has been studying the behavior
of the pollen tubes of Melothria pendula, Micrampelis lobata, and Cyclanthera
explodens. He has noted that the time elapsing between pollination and the
arrival of the tube at the embryo sac in these species is 26, 19, and 41 boas
respectively. The tubes pass chiefly over the surface of the conducting pete
lining the stylar canal and covering the “placental lobes,” and this is rich in
starch. The suggestion is made that the tube is directed by “nutritive sub-
stances secreted by the conducting tissue,” and that it “comes. under the influence
of a stronger stimulant emanating from the ovule,” and “the source of this
stimulus may be the endosperm nucleus.” —J. M. C

Morphology of Phyllocladus.—Miss Roper Tsons* has obtained some glimpses
of Podocarpus from cultivated species and five collections of P. alpinus secured
in New Zealand by Dr. Cockayne during 1902, 1903, and 1904. It is disap”

pointing to learn that no critical stages were fixed, and that we are still - z
= st to ea

Taxaceae.—J. M.

Parichnos in recent plants.—Hri13? has reached the conclusion that P&P
ichnos, a name given by BERTRAND to the strand of thin-walled parce
tissue accompanying the leaf trace in a species of Lepidodendron, is a
among living species of Lycopodium and Isoetes by certain mucilage cana
The tissue to which the name was given is simply an early developmental se
of the canal. In recent plants parichnos is restricted chiefly to the sporophy
as, for example, in Isoetes Hysirix, where two canals run longitudin
side of the sporangium, but do not extend into the cortex of the stem, aS
case in fossil forms.—J. M. C

3° Kirkwoop, JosepH Epwarp, The pollen tube in some of the Cucurbitacea®
Bull. Torr. Bot. Club 33:327-342. pls. 16-17. 1906.

3* ROBERTSON, AGNES, Some points in the morphology of P: hyllocladus
Hook. Annals of Botany 20:259-265. pls. 17-18. 1906. poe ol

alpinus

3 Hit, F. G., On the presence of a parichnos in recent plants.
Botany 20:267-273. pls. 19-20. 1906.

1906] CURRENT LITERATURE 235

Spore formation in Botrychium.—-The development of the spores and the
behavior of the tapetum in Botrychium virginianum are described by STEVENS.34
Carorrr had already published an essentially identical account of the tapetum.34
STEVENS’S term fapetal plasmodium seems to be a suggestive and convenient
name for the peculiar tapetal mass as it appears in Botrychium and many other
pteridophytes. The behavior of the kinoplasm and trophoplasm during the
formation of spores from the mother cell indicates that these two plasms are
interchangeable, each being able to become transformed into the other.—CHARLES
J. CHAMBERL

Dichotomous leaves in Cycas.—SEWARD®5 has called attention to the dichot-
omous leaves of C. Micholitzii, a subterranean-stemmed species from Annam.
Most of the pinnae are repeatedly dichotomous, but the terminal pinnae are
simple and similar to those of other species of the genus. It seems that dichot-
omous pinnae in the cycads were first noted by Moore in the Australian Macro-
zamia heteromera. The author suggests the possibility that the usual simple
pinnate type of the cycadean leaf “may be the result of reduction from an older
type characterized by the more primitive dichotomous habit.”—J. M. C.

Diatomin.—Kout was incited by the papers of Moxiscu?® and Tswerrs?
to reinvestigate the coloring matter of diatoms,3® having denied in his work on
carotin the existence of a special pigment, ‘“‘diatomin.” He now finds that
his conclusion was correct as regards any special “diatomin; ” but the pigment

absorption spectrum as in higher slain being ae pre esent. "The leucocyan
of MouiscH he does not find. The yellowish or brownish hue of the diatoms
is due to the prevalence of carotin as compared with the higher plants.—C. R, B
Germination in Ophioglossum.—The difficulty and the desirability of secur-
ing the germination of the spores of the pteriodophytes with tuberous gameto-
phytes are well known. CAMPBELL announces (Annals Bot. 20: 321) in a brief
note that he has secured germination in certain Javanese species of Ophioglossum.
In every case the characteristic endophytic fungus was present beyond the
three-celled stage. In one case a gametophyte of thirteen cells was found; but
no stage between this and mature gametophytes were secured.—J. M. C.
BR ee ee

33 STEVENS, W. pore formation in Botrychium virginianum. Annals of
Bot. 19: dae nh — 1906.
*#Carprrr, I. D., The development of the sporangium of Botrychium. Bor.

Gazerre A ioe "pl. 9. 1905.
8s SEWARD, A. C., Notes on Cycads. Proc. Cambridge Phil.-Soc. 13: 293-302.
1906.

3° Mouiscn, H., Bot. Zeit. 63": 131-162. 1905.
37 Tswetr, M., ibid. 273-278.
* Kout, F. G., Die Farbstoffe der Diatomeen-Chromatophoren. Ber. Deutsch.
Bot. Gesells. 24:124-134. 1906

236 BOTANICAL GAZETTE [SEPTEMBER

Cytology of Entomophthoraceae.—One species of Empusa and four of
Entomophthora have been studied by Riddle.s> In Entomophthora the division Is
more or less typically mitotic. During prophase the chromosomes are formed by

s
chlamydospore. Cytological conditions indicate that Entomophthora is a more
highly developed genus than Empusa.—CuHartes J. CHAMBERLAIN.

Lime and sphagna.—As a result of cultures PAvt, in a preliminary paper,”
confirms the older and still prevalent idea that the sphagna are very sensitive
to the presence of CaCO, in the water in which they grow, and controverts the
pronouncements of WEBER and of GRAEBNER. Sphagnum rubellum se
sensitive, bearing less than 77™s CaCO, per liter (i. e., 0.0077%); while S.
recurvum, least sensitive, bears less than 3128, S. rubellum changes its beautiful
red to a blue, indicating an alkaline reaction, the more clearly the higher the
lime content of the solution —C. R. B.

Julianiaceae.—Under this name Hemsiry4™ has established a new family
of Mexican plants, known at present to contain two genera (Juliania and Ortho-
pterygium) and five species. Its closest relationships are said to be with the Ans-
cardiaceae and Cupuliferae; but the final judgment of the author places it m
linear arrangement between Juglandaceae and Cupuliferae. “The ener
separation of the sexes and the very great diversity of the floral structure of ms
sexes, associated with pinnate leaves, offers a combination of characters Pr
ably without a parallel.”—J. M. C.

Fossombronia.—Humparey has described? in detail the germination of ra
spores and the development of the sex organs of a Californian species, F. feed ;
the first investigation of any member of the genus since LEITGEB’S, aides e
years ago. No striking anomalies appear. No centrosome was observ re
any stage of nuclear division; blepharoplasts seem to appear de nove, ee
Nebenkérper likewise, forming the middle piece of the sperm. The
are of the pyramidal form described by IkENo in Marchantia, with n0
between the pair.—cC. R. B. z

39 RippE, Lincoin W., Contributions to the cytology of the Entomophthoraces*;
preliminary communication. Rhodora 8:67-68. 1906 h. Bot
4° Paut, H., Zur Kalkfeindlichkeitsfrage der Torfmoose. Ber. Deutsc™
Gesells. .24:148-154. 1906. P ‘.

4* HemsLey, W. Bortinc, On the Julianiaceae, a new natural order of pla”
Abstract. Read before Royal Society, London, June 28, 1906.

42 Humpurey, H. B., The development of Fossombronia longiseta
of Botany 20:83-108. pls. 5-6. 1906.

Aust. Annals

1906] CURRENT LITERATURE 237

Anatomy of the Araliaceae.—VANn TreGHEM* has published the results of a
very extended anatomical study of the Araliaceae as a basis for their classifica-
tion. He is convinced that he has discovered anatomical characters that are of
great service in this way, and he applies them in establishing groups of genera,
in making diagnoses of genera more precise, and in clearing up the positions of a
number of critical species. The following six new genera are characterized:
Bonmierella, Mesopanax, Plerandropsis, Octotheca, Strobilopanax, Schizomeryta.
pa C.

Germination among palms.—Gatin‘*+ has published an extended study
of germination among palms, having included in his researches 58 species, repre-
senting 33 genera. The first and far the larger part of the paper deals with
what are called “anatomical’’ studies, and one conclusion that is reached, among
several others, is that the “cotyledon,” so far as palms are concerned, is a single
leaf and not a phylogenetic coalescence of two leaves. The second part deals
with the chemistry of germination.—J. M. C.

Water relations of the coconut.—The anatomy of the root and leaf of this
palm, as well as the conditions affecting the entrance and passage of water through
the plant, have been investigated by CopELAND.45 Maximum transpiration is
found to favor maximum yield of fruit. Wind and intense sunlight accelerate
transpiration. The roots should be abundantly supplied with water, pte
an excess is injurious. Irrigation is altogether practical—Raymonp H.

Fossil roots of Sequoia.—LicnieR*® has identified the roots called aa
culites reticulatus as those of Sequoia, or of some allied form as Taxodium.
The material studied is from the Stephanian of Grand’ Croix, and its distinguish-
ing feature is the reticulated cortical parenchyma. Comparing it with roots of
similar structure in living plants, the conclusion is reached that it most nearly
resembles the structure observed in the root of Sequoia gigantea. —J. M. C.

N. Am. Vernonieae.—G1Eason‘? has published a revision of the North
American species of Vernonieae. Seventeen genera are characterized, two of
which (Eremosis and Orthopappus) are new. The species number 143, of which
28 are new. The large genus is Vernonia, with 99 species, 25 of which are new;
and the new genus Eremosis includes 1 5 Fee 13 of which have heretofore
a usually to Vernonia.—J. M. C

43 VAN TIEGHEM, PH., Recherches anatomiques sur la classification des Araliacées.

Ann. Sci. Nat. Bot. IX. 4:1-208. figs. 54. 1906.

44 Gatin, C., Recherches sur la ae des palmiers. Ann. Sci. Nat. Bot.
IX. 3:191~-315. pls. rr. figs. 58. 1906

45 COPELAND, E. B., On the water relations of the coconut palm. Philippine
Jour. Sci. 1: 6-57. pls. 3. 1906.
4° Licnter, O. » Radiculites ape radicelle fossile de Séquoinée. Bull. Soc.
France IV. 6:193-201. figs. 5. 19
*7 GLEason, H. A., A revision oF oe North American Vernonieae. Bull. N. Y.
Bot. Gard. 4:144-243. 1906,

Bot.

238 BOTANICAL GAZETTE [SEPTEMBER

Apical meristems of monocotyl roots.—Daisy G. Scorr*® has investigated
the root tips of Alisma, Butomus, Vallisneria, Ruppia, Zostera, Naias, Strati-
otes, and Limnocharis. Her results support Dr BARy’s statement in reference
to the roots of monocotyledons in general, namely that there are three distinct
groups of initials, one giving rise to calyptrogen, another to dermatogen and pet
iblem, and the third to plerome.—J. M. C

Megaspores of Lepidostrobus.—Mrs.°D. H. Scott? has found that certain
megaspores referred to Kipston’s Triletes belong to Lepidostrobus foliaceus,
heretofore regarded as homosporous. They are peculiar in bearing a cOnepiot
ous appendage, said to be suggestive of the so-called ‘swimming apparatus
of Azolla. Many of these spores were found, and they are spoken of as “fairly
common objects.”—J. M. C.

N. Am. Hydnaceae.—BANKER®° has published a revision of the pileate forms
of Hydnaceae found in North America north of Panama, and including the adja-
cent islands. A few resupinate forms are included, but in general they ate
excluded, awaiting an examination of the Berkeley types. Ten genera are pre
sented, two of them being new (Leaia and Grandinioides), and of the 63 species
10 are new.—J. M. C.

Fossil germinating spores.—Scotts! has announced the discovery of ger

minating spores in a sporangium of Stauropteris Oldhamia. The discovery ®
important, for it has been in doubt whether this species should be regarded as
a fern or a pteridosperm. The germination is distinctly fern-like, and confirms
the anatomical resemblance of this species to the Botryopterideae.—J. M. C.

Apple scab. LAWRENCE:? reports further studies of the apple scab in Wash-
ington. In a comparative test-of the relative effects of the dust spray ore
and the ordinary liquid Bordeaux it was found that the liquid was twelve times
as effective as the dust spray. This is in accord with the results secured by
CRANDALL‘S in Illinois—E. Mreap WItcox.

48 Scott, Datsy G., The apical meristems of the roots of certain aquatic mon®
cotyledons. New Phytol. 5:119-129. pl. 9. 1906.

49 Scott, Rina, On the .megaspore of Lepidostrobus foliaceus. New
5:116-19. pl. 8. figs. 24-25. 1906.

s° BANKER, H. J., Acontribution to a revision of the North American Hydnaceat:
Mem. Torr. Bot. Club 12: 99-1094. 6

Phytol.

st Scort, D. H., The occurrence of germinating spores in Stauroplerts Oldha
6

New Phytol. §:170-172. 1906.
52? LAWRENCE, W. H., Apple scab in Eastern Washington. B
Sta. 75:1-14. 1906. pli-
53 CRANDALL, C. S., Spraying apples. Relative merits of liquid en oe i
cations. Bull. Ill. Exp. Sta. 106:205-242. pls. 1-9. figs. I-5- 1906. :
Bot. GAZETTE 42:157. 1906. .

ull. Wash. Exp:

NEWS.

Dr. H. A. GLEAson has been appointed instructor in botany in the University
of Tlinois.

F. S. Earve has retired from the directorship of the Estacién Agronémica
Central de Cuba.

Dr. A. A. Lawson, Stanford University, has been advanced to an assistant
professorship in botany.

C. B. Crarke, the well-known English systematist, died at Kew August 25,
at the age of seventy-four years.

Dr. J. N. Rosr, United States National Museum, left August 1 for his
sixth collecting trip in Mexico, being especially interested in the Cacti.

PROFESSOR CHARLES FLAHAUT, Montpellier, has been elected an honorary
member of the Zoological and Botanical Society of Vienna.—ScIENCE.

Mr. Joun G. Haut, Harvard University, has been appointed assistant in
plant pathology in the North Carolina Agricultural Experiment Station.

DuRING 1904 the additions to the Kew Herbarium were as follows: 8000
sheets presented by ninety persons and institutions; 4000 sheets purchased.

Proressor C. R. Barnes, Dr. C. J. CHAMBERLAIN, and Dr. W. J. G. Lawn,
University of Chicago, have spent the month of September in botanical work
in Mexico.

Dr. H. C. Cowzes, University of Chicago, will spend the autumn and early
Winter in Florida, studying the everglades under a grant from the Carnegie
Institution.

Dr. A. F. BraKestrr has been appointed instructor in cryptogamic botan
in Harvard University for the ensuing year, and will also give instruction in
Radcliffe College. He has recently returned from two years study at Naples
and Halle.

IN COMMEMORATION of the twenty-fifth anniversary of its foundation, Sep-
tember 31907, the German Botanical Society proposes to publish a Festschri/t
of ahout 300 pages and 20 plates; and distinguished specialists, whether mem-

FS or not, are asked to offer MSS. before January 1, 1997, to the Secretary,
Professor Dr, C. MULter.

THE DEATH or H. MarsHALL Warp, professor of botany at Cambridge
University, is announced as having occurred August 26. He succeeded Profes-
sor C. C. Basincton at Cambridge in 1895, and died at the age of fifty-two years.
His work on plant diseases is well known, and the splendid new botanical building,
which was the result of his tireless activity, had only been occupied for two years.

239

_ 240 BOTANICAL GAZETTE [SEPTEMBER

Tureme in Leipzig, will be published, beginning with the twentieth volume, by
C. Hernricu of Dresden. It will continue under the same editors, Drs. OSCAR
Untworm of Berlin and F. G. Kont of Marburg, and with the same two
sections. The indefinite size of the parts enables the- editors to promise pub-
lication with the utmost promptness.

Tue Commirree on “Applied Botany” of the International Association
of Botanists met in Paris August 25-27, fourteen members being present. Tn
addition to the customary addresses, it was decided to appoint a botanist to make
a tour of the world to investigate and report upon the “resources of applied
botany,” the report to be made at the general meeting of the Association in 1908.
It was estimated that 20,000 francs would be needed for this purpose, and the
selection of a suitably trained botanist was left in the hands of a committee. It
was decided to raise the money from various governments and public estab-

THE Bethejte zum Botanischen Centralblatt, heretofore published by GEORG
b

diseases and to attempt to secure international legislation in reference to ng

A TIMELY MOVEMENT has been started in New Zealand to preserve the “Ric
carton Bush.” ‘This fact is of great interest to botanists in general, for this
“Bush” is the only remaining portion of a vast forest that once covered the
region, and is the last piece of forest of its kind in the world. It is near the
city of Christchurch, and a list of its species shows a combination of rare | ge
that exists in no other place. The dominant tree is Podocarpus dayne
and other large trees are P. totarra, P. spicatus, Elaeocarpus deniatus, and
Hookerianus. If this forest were destroyed, it would be a distinct loss to botani
science, which for years to come wil! need the material it can supply. 5S
government of New Zealand has voted £1500 toward its acquisition, and t a
is still some £5000 to raise. It is to be hoped that nothing will interfere W’
‘ the success of this movement. Those interested in it may communicate

r. L. Cockayne, Ollivier’s Road, Christchurch, N. Z.

CONTENTS —

The Development of Agaricus cal r |
Réle of Seed Coats in Delayed Germination

VOLUME XLII . NUMBER 4

BOTANICAL GAZETTE

OCTOBER, 1906

THE DEVELOPMENT OF AGARICUS CAMPESTRIS.*
Gro. F. ATKINSON.
(WITH PLATES VII-XI1)

IN some respects the history of the study of the Hymeniales does
not present the same progress which can be seen in the other groups
of fungi, or indeed in nearly all other groups of plants. The earliest
period, that of the study and classification of species and genera,
presents in the main the same aspects which have been characteristic
of the early study of all plants; but the progress made up to the present
time is not in proportion to the time and energy expended, due to
certain difficulties, some inherent in the nature of the plants them-
selves, and others due to the lack of an adequate knowledge of their
anatomy and development.

The second period, that of the study of the morphology and
development, began more than half a century ago. It is true that in
the early part of the 19th century, nearly a century ago, quite an
elaborate theory of the development of the Hymeniales, especially
the Agaricaceae, was evolved by NEES von EsENBECK.’ But his
theory, embellished as it is with his philosophical ideas of the evolu-
tion and metamorphosis of these plants from the puffballs and truf-
fles; in which he was evidently influenced by the philosophy expressed
in the Vorwort of GorTHE’s Farbenlehre, that in a book dealing with

* Contribution from the Department of Botany of Cornell University. No. 110.
Paper presented before Section G, of the A. A. A. S., at the New Orleans meeting.

* Das System der Pilze und Schwimme, ein Versuch von Dr. C. O. NEES VON
ESENBECK, I-XXXVI, 1-329, 44 plates, Wiirzburg, 1816. See also NEES VON EsEN-
BECK, Plantarum Mycetoidarum in Hort. Bonn. obs. evolutio. Nov. Act. Natur. Curios,
16: pars 1, 1832, for development of Agaricus volvaceus.

241

242 BOTANICAL GAZETTE [OCTOBER

natural phenomena the writer should make use of a lively imagina-
tion in order to make it real to the reader; and especially because
there is such lack of definiteness as to the forms studied, though it
is quite evident he refers more especially to species of Amanita, pre
sents little that is helpful to the present discussion.

At that early period it was an important forward step to show, as
___Durrocnet? did in 1834) that the large fungi were only the fruit
bodies of thé plants then known as “Byssus,” which spread usually
underground or in the substance of organic bodies; and for TROG*
in 1837 to recognize the two different parts in the life history, the
vegetative stage or mycelium and the fruiting stage or carpophore,
and that this is the product of germinating spores; though MICHEL
had stated as early as 17294 that the fruit bodies of some fungi did
not come immediately from the seed (spores), but the seeds first pt
duce a large root which grows for several years in the ground, and
then gives rise to the fruit body (referring to Polyporus tuberaster).
But during the early and middle portion of the 19th century the work
on the morphology and anatomy of these plants, and the descriptions
and illustrations of species, was far in advance of the work on develop-
ment and the organization of the parts of the fruit body. Unfortu:
nately the study of the morphology and development of the Hymeniales
has not kept pace with the same studies in other groups of plants.
J. Scumrrz’ studied the very early stages of five different spre
While the work appears to be very carefully done for that early time,
it does not meet modern requirements; and while his results perhaps
in the main are not far out of the way for the species.studied (Ce
tharellus sinuosus, C. tubaeformis, Cortinarius bulliardi (Pers.) Fi
Coprinus niveus, Hydnum imbricatum), it will be seen later he ge
led into a mistake in formulating a general law, based on — 2s
species, to apply to the development of all the pileate fungl.

2 Mém. 2:173. 1834.

3 Ueber das Wachsthum der Schwimme, Flora 20:609. 1837-
4 Nova plantarum genera 134. 1729.

und Entwickeluns

5 Mycologische Beobachtungen, als Beitrage zur Lebens- ape nomyecetel

geschichte einiger Schwimme aus der Klasse der Gastromyceten un :
Linnaea 16: 141-215. pls. 6-7. 1842. See especially the part Il, Ueber cor
neuer Theile bei den Hymenomyceten, vorzugsweise den Pileaten. Idem 1

1906] ATKINSON—AGARICUS CAMPESTRIS 243

BoNoRDEN® deals briefly with the anatomical structure of the
genera recognized by Fries in his Epicrisis. He does not discuss
the differentiation of the parts in the young fruit body, but describes
somewhat in detail the different forms of the universal veil, its mode
of dehiscence, and its relation to the partial veil and the pileus in
certain species of Lepiota (pp. 178-181). He says, very briefly (p. 8):
“From the mycelium rises the fruit body of the fungus (stroma,
thallus), either naked from the first or enclosed in an envelop (velum,
volva). The latter consists always of very much elongated cells,
tubes, which are like the tissue of the mycelium, and has therefore ,
always a structure very different from that of the fruit body of the
fungus; it is to be regarded as a continuation of the mycelium, The
envelop is ruptured by the further growth of the pileus and is thrown
off, but sometimes remains a part of the same and forms the epidermis
of the pileus, on which account this is so different in structure in the
case of the gastromycetes and pileated fungi from the other parts
of the fungus.”

H. Horrman contributed at that time some important work on
‘the anatomy and morphology, and as early as 1856 gave a very
brief account of the origin of the hymenium of A garicus campestris.”
In speaking of his studies of the developmental history of the lamellae
in very different types (J. c. , P. 145) he cites three extremes: Agaricus
carneo-tomentosus (Panus torulosus), where they arise at the apex of
the young fruit body; Agaricus campestris, where they originate
deeper in the interior and develop laterally; and Hymenogaster
klotzschii, where they remain concealed in the interior of the fungus.
In describing the development of Agaricus campestris (p. 145) he
Says (I give a free translation): “It begins, as BULLIARD has already
very well represented (Champ. d. France. pl. 514, fig. L. 1791-1809),
in the form of small spheres which for a part rest upon thick mycelium
Strands, This stroma is formed as in the former case [A garicus
carneo-tomentosus, the stroma of which, he says, at first quite homo-
8eneous, is formed out of felted filamentous cells]. Gradually the
same takes on an elongate form; the interior cells grow in a perpen-

© Handbuch der Allgemeine Mycologie 147-196. 1851.

ag ’ Pollinarien und Spermatien bei Agaricus. Bot. Zeit. 14:137-148, 153-163.
+ 5. 1856.

244 BOTANICAL GAZETTE [OCTOBER

dicular direction, the upper ones grow laterally, and then bend
abruptly downward; the ends of these cells abjoint a parenchyma
which forms the beginning of the lamellae; the under surface of these
young lamellae is somewhat even and has no longer any connection
with the stroma tissue lying close beneath, which later sinks down as
a ring. The hymenial layer opens here round about at the side.”

A few years later® he describes the development of a number of
additional forms, all of which were gymnocarp except one, Maras-
mius oreades, and he remarks (p. 401) that this peculiarity of the
internal origin of the hymenium is characteristic of many other
Agaricaceae, as was shown in his larger work? which appeared in
the following year.

The work of HorrMann was followed by DEBary’s'® study of
the development of several species of Agaricaceae and Gastromycetes,
by Hartic’s study of Agaricus melleus,** by BREFELD’s studies 00
species of Coprinus,?? and by the incomplete study of a large number
of Agaricaceae by Fayop*3 nearly twenty years ago, which was the
last serious attempt (which I have as yet seen) at a study of the
development of the Agaricaceae. Even these few studies do not agree
in the account of development which they give of the same or related
species. Furthermore, they are very incomplete and unsatisfactory,
owing either to the methods employed (freehand sections by the earher
students), or in the scanty material at hand, which did not provide
sufficient numbers of the early stages of development or a sufficiently
full series of stages.

The difficulties in method are now overcome, bu
culties, those of obtaining sufficient material in all stages of

ment, are still serious in the great number of species. This is
e und Anatomie der

t the other diffi-
develop-
because

ERMANN HOFFMANN, Beitrige zur Entwickelungsgeschicht
Agaricineen. Bot. Zeit. 18: 389-395, 397-404. pls. 13-14. 1860. oer
9 Icones Analyticae Fungorum, Abbildungen und Beschreibungen vo? Pilzer
besonderer Riicksicht auf Anatomie und Entwickelungsgeschichte 1-195: pls. I
1861

: P
© Morphologie und Physiologie der Pilze, Flechten und Myxomyceten
66.

‘t Wichtige Krankheiten der Waldbaume, etc. 25. 1874-

‘2 Unters. a. d. Gesammtgebiet d. Mycol. 3:13-122- pls. I-9- 1877- VIL.

+3 Prodrome d’une histoire naturelle des Agaricinées. Ann. Sci. Nat. Bot.
9:181-411. pis. 6-7. 18809.

1906] ATKINSON—AGARICUS CAMPESTRIS 245

of the fact that at present few species have been cultivated artificially
(exceptfin the genus Coprinus by BREFELD, /. c.) so as to obtain the
stages df development, and because the feral species nearly all pass
their early and critical stages of development within the substratum
and therefore are difficult to find, and at the same time it is often
difficult to be certain to what species they appertain. These difh-
culties have probably played an important part in discouraging the
further study of development of the Agaricaceae.

It is rather surprising, however, that even in the present time we
do not have a sufficiently clear, full, and accurate account of the
development of the fruit body of Agaricus campestris, especially the
origin and differentiation of the various parts of the plant. This
is the more so because this species is so common and of such wide
distribution, but especially because it has been cultivated for so
many years under conditions in which large numbers of carpophores
in all conceivable stages of development are so easily obtained. Per-
haps the very commonness and richness of the material has been
the chief reason of its having been passed by.

Having given some attention to the study of the Agaricaceae for
several years, especially as to their economic and biologic significance,
as well as to the recognition of species and genera, the need of studies
of development has been brought very forcibly to my attention, and
I have been obtaining material for this study in several different
genera, The meager and conflicting accounts which we have of the
development of Agaricus campestris, as well as the ease with which
material can be obtained, has led me to deal with this species first.

DeBary" says the fruit body of many Agaricaceae (Agaricus
campestris, A, praecox, Coprinus micaceus and relatives) is in its
early youth a body interwoven out of delicate, dense, and uniform

yphae. At a very early stage, through differentiation of the original
homogeneous weft, the principal parts of the fruit body are outlined
and limited. On the interior of the upper part of the body a small
and narrow air space of the form of a horizontal ring arises through
the separation of the tissue elements. The portion which lies above
becomes the pileus, the tissue present surrounded by it and below it

s ** Morphologie und Physiologie der Pilze, Flechten und Myxomyceten 68. 1866.
ipzig.

246 BOTANICAL GAZETTE [OCTOBER

becomes the stem. The tissue on the outside of it corresponds to
the edge of the pileus, but its hyphae continue without interruption
or change into the outer surface of the stem below.

In 1874 R. Hartic,'5 in his study of the development of Agaricus
melleus, says that “the investigation of the earliest condition of the
fruit body of Agaricus melleus shows that here, as well as in the
Agaricaceae not provided with a veil, the pileus arises through a
superficial annular furrow which in the beginning is completely open
to the outside, and that later through growth of the marginal hyphae
of the pileus and of the stem the annular furrow becomes covered
over with a hyphal layer, the veil.” He further says that if one
compares his fig. 20 (which shows the veil covering the hymenial
tract) with DeBary’s fig. 26 (1. c.) of the young Agaricus campestris,
“it appears from the agreement of the two figures that the con-
jecture is justified that also by this last fruit body in the region of the
hymenial tract a subsequent growing together of the hyphae of the
pileus and stem has taken place.’’ Longitudinal sections of the
young fruit body of A garicus campestris at this stage do give the sug:
gestion that the veil originates as Hartic described for Agaricus
melleus. DEBary evidently did not study the very young stages of
Agaricus campestris, for all his figures of longitudinal sections show
the veil covering the hymenial area. It seems that without reinves-
tigating the question he adopted Harric’s suggestion that the
development in Agaricus campestris followed the same course as that
described by Harrie for Agaricus melleus, In his later work?* he
says in reference to those forms with a “marginal veil” (velum
partiale of Fries): “Up to the first formation of the pileus 0? the
summit of the stipe-primordium the phenomena are the same a
essential points as in the gymnocarpous forms” (referring 2 his
figures of Collybia dryophila, p. 55). “The young pileus is entirely
delimited from the stipe by a transverse annular furrow runmns
along its future hymenial surface, But then the superficial hyP
layers of the stipe and of the young pileus send out numerous branches
toward one another from the edges of the furrow; these unite into

15 Wichtige Krankheiten der Waldbaume, etc. 25. pl. 106. 1874-

*6.Comparative morphology and biology of the fungi, etc. 289-29°
English edition.

1887-

rt
a
:
&
i

1906] ATKINSON—AGARICUS CAMPESTRIS 247

a close weft, the marginal veil, which bridges over the furrow and
closes it on the outside” (referring to figure of Agaricus melleus
copied from Hartic), To be certain that DeBary here refers also
to Agaricus campestris I quote also from page 291: ‘‘ Most marginal
veils are formed in the same way as that of Agaricus melleus, and
jig. 132 of A. campestris will serve to illustrate these remarks.” Fig.
132 is reproduced from his original work in 1866. In addition, on
page 295 he says: ‘The account given above of the development of
the species which are furnished with a marginal veil is founded,
wherever it departs from my former statements, chiefly upon the
facts discovered by Hartic and BREFELD;” and on page 297, after
discussing the different types of development in the Agaricaceae and
his former statements, he says: “So far as these statements related
to Coprinus they have been shown by BREFELD’s researches to be
incorrect; my own did not pay sufficient regard to the earliest stages
of development. I will not even maintain that they are quite correct
for Agaricus campestris, . . . . but readily allow that the facts in the
case are always the same as in A. melleus, and that the first extension
of the marginal veil over the hymenial surface which was originally
exposed had there also been overlooked.”

GOEBEL"? says: “These veil-formations are connected with the
entire growth of the fructification; the species with a naked pileus
are by their nature gymnocarpous.” In speaking of the young fructifi-
cations of A garicus campestris, he says: “These are at first pear-shaped
bodies composed of young uniform hyphae, and each of these bodies
is a rudimentary stipe, from the upper part of which the pileus will
be developed. At an early period the hyphal tissue gives way in
such a manner as to form an annular air cavity beneath the summit
of the stalk, this cavity enlarges with the growth of the whole body,
its upper wall forming the under side of the pileus, from which the
radial hymenial lamellae grow in downward direction and fill up
the cavity.” His account thus supports DEBary’s earlier account,
but the evidence presented in illustrations is not sufficiently con-
vincing in view of the controverted nature of the question and espe-
cially in view of the fact that gross anatomy and freehand sections

. Outlines of classification and special morphology of plants 132-134. 1887.
English edition.

248 BOTANICAL GAZETTE [ocTOBER

do not show the early stages of organization and differentiation, and
GoEBEL’s figures (jig. 89, J. c.) of the section of the young fruit bodies
are made after the young pileus is differeatiated from the stipe. No
evidence is given that this text book account is the result of original
investigation, and it is more likely that GorBet here is relying on
the early account given by DEBary, and the still earlier one given
by HorrMann cited above.

In a similar way, in describing the early stages of development
of Agaricus campestris,7® I have followed DEBary’s later account
as follows (p. 7): “At the same time a veil is formed over the gills
by threads which grow from the stem upward to the side of the but-
ton, and from the side of the button down toward the stem to meet
them. This covers up the gills at an early period.” Aside from
the extensive work of Fayop in 1880,'® little work seems to have
been done on the development of the young sporocarps of the Agar
caceae since the publication of DEBary’s work in 1887.

In January r905 an excellent opportunity presented itse
obtaining material in the required stages of development. Cultures
had been made in boxes in the greenhouse of the commercial variety
of Agaricus campestris known as Columbia, sold by the Pure Culture
Spawn Company of Missouri, In many cases large numbers of
young carpophores were formed at the surface of the substratum
which were clean and in excellent condition for study. Preliminary
examinations were made by freehand sections, and by staining a
order to determine the age and size of the fruit bodies which shoul
be prepared. In fruit bodies about 1™™ in diameter there don no
evidence of a superficial annular furrow nor of any internal differen
tiation, Fruit bodies, therefore, from 1™™ to 4™™ were selected,
fixed in chromo-acetic acid, imbedded in paraffin, microtomed, 4”
stained, some in acid fuchsin and some in methyl blue.

The youngest stage is the primordium of the carpophore, 4 —

tricately
of

lf for

geneous body composed of slender uniform dense hyphae, 1” “
interwoven, and surrounded by a very thin layer of hyphae
*8 Studies in American fungi, mushrooms, edible, poisonous, et» eae
Ithaca, N. Y., 1900; 2d ed. 1901; and New York 1903.

19 Prodrome d’une histoire naturelle des Agaricinées. Ann. Sci.
Q9:181-411. pls. 6-7. 1889.

Nat. Bot. VII.

1906] ATKINSON—AGARICUS CAMPESTRIS 240

looser and less dense arrangement. This layer is the “universal
veil.” It is quite distinct in the young stages of these cultivated
varieties, continues to increase in extent until the parts of the fruit
body are differentiated and the young pileus and stem are manifest
by external differences in form. Then it ceases to grow and is torn
apart into white floccose patches on the pileus, as will be seen later.
In the very young primordia then there is no evidence of a differen-
tiation into stem and pileus in any of the many individuals which I
have examined, As the primordia become slightly larger and older,
but still before there is any evidence on the outside of an annular
furrow or of any differentiation into pileus and stipe, longitudinal
sections which are stained show two small deeply stained internal
areas near the upper end of the young fruit body and some distance
in from the surface. The hyphae here are not yet differentiated,
but are richer in protoplasm, showing the origin of a new and special
center of growth. This area is an annular one within the fruit body.
Very soon afterward this area increases somewhat in extent and
many hyphae begin to grow from the upper portion of this area
downward. This is the primordial layer of the hymenium. It first
arises when the tissue of the fruit body is homogeneous and compact
except for the loose thin envelop. The hyphae which grow downward
at this early stage are quite characteristic, They are slender and
terete, tapering out into a long slender point. This enables them
to pierce between the other hyphae of the compact fruit body. In
fact at this time there are similar hyphae in the more central and
upper portions, where the stem and pileus are to be differentiated,
but in no other place at this time is there a definite center of growth
which indicates the organization of any special part. ‘These hyphae,
partly at least, provide for intercalary growth of the young fruit body.
Soon after the hyphae in the primordial layer of the hymenium begin
to grow downward, there is a cessation of growth just below this
— which results in the rupture and separation of the hyphae at this
point in a corresponding internal annular area, forming the well
known “gill cavity,” which at first is very minute.

_ This annular primordium of the hymenium marks the differentia-
tion of the primordium of the fruit body into the primordium of the
pileus and that of the stem and veil, the latter being the tissue of

250 BOTANICAL GAZETTE [OCTOBER

the young fruit body external to the hymenial primordium and con-
tinuous with what is to be the margin of the pileus above and with
the undifferentiated stem surface below. The downward growing
hyphae now take on a different form. They are still slender, but are
even and blunt and are very densely crowded side by side, are very
rich in protoplasm compared with the hyphae of the rest of the young
carpophore and consequently take a deep stain.

This first growth takes place on the under side of the young
pileus primordium. The vegetative activity in this region of the
young pileus is very great, and is very soon extended outward on
the periphery or margin of the young pileus, as shown by the very
rapid radial growth of the hyphae at the margin of the pileus, but
still some distance in from the surface. This radial growth is also
accompanied by a very strong hyponastic growth, so that the threads
curve downward, and soon it is so strong that the margin of the pileus
is strongly incurved, the hyponastic growth appearing to be stronger
at the margin and near it than further inward.

At the same time the primordium of the marginal veil increases
by intercalary growth. In the participation of the hyphae at the
margin of the pileus in the formation of the veil, they seem to show
a greater activity in growth so far as the density of the growth and
richness in protoplasm is concerned; while the larger portion toward
‘the stem, also increasing by intercalary. growth, becomes looser by
the rapid elongation of its elements and their partial separation,
thus forming numerous small air spaces. This seems to have big
important bearing on the supply of fresh air to the young forming
hymenium where the air spaces become continually larger, and the
first air space formed underneath the annular primordium © the
hymenium not only gives place for the development of the latter but
also provides aeration. Thus while the veil serves the purpose ©
protection to the young hymenium, its structure is such as to provide
aeration also, After the differentiation of the hymenial primordium,
the lateral growth of the pileus is accentuated so that it ie
broader than the stem portion, and now is formed the external ann
furrow. Very soon after the hymenial primordium is O ue fe
the tissue of the pileus primordium, or end of the fruit body, ee
on a deeper stain in an area extending inward and some depth belo

1906] ATKINSON—AGARICUS CAMPESTRIS 251

the surface, showing that the pileus primordium is becoming definitely
organized through the central portion (fig. 4), also sometimes seen
in freehand sections in older stages as a compact area (fig. T5).

In the very early stage of the hymenial primordium the under
surface is even, but very soon the outlines of the gills begin to form
by the more rapid downward growth in radial lines. Very soon
after the young gills begin to form, the surface of the stem is differen-
tiated, This occurs in such a way as to show that the surface of
the stem portion of the young fruit body does not become the surface
of the stem except at its extreme lower portion, which probably cor-
responds to the bulb even when a bulb is not manifest as a thicker
portion of the stem. From a point at the junction of the original
annular primordium of the hymenium, or the junction of the young
stem with the pileus at the inner end of the gills, and then extending
obliquely downward and outward, the hyphae take on more active
intercalary growth and a richer content of protoplasm. This marks
the origin of the cortex of the stem, and distinguishes it very sharply
from the elements of the veil and from the internal tissue of the stem
which is to be the medulla by a deeper color in stained preparations;
also in fresh freehand sections it is usually very clearly seen with the
unaided eye asa whitish more compact area which shows well in
- ordinary photographs at this stage.

This study shows very clearly that the hymenium in Agaricus
campestris is endogeneous in its origin, as HorrMann described so
early as 1856 (J. c.), and that DeBary’s first account of the develop-
ment of this species ia 1866 was correct so far as it went; but he did
hot succeed in obtaining for study carpophores sufficiently young to
enable him to speak with certainty after Hartic had thrown doubt
on his conclusions as a result of his study of Agaricus melleus.

Not only is the hymenium endogenous in its origin, but the differen-
tiation of the stipe and pileus is simultaneous; that is, the initial
Stages of the stipe and pileus as distinct structures are organized and
made evident in longitudinal sections by the origin of the hymenial
Primordium, In all the sections that I have examined of this species
at this Stage, there is no evidence of differentiation of the pileus
from the stem before the earliest evidence of the hymenial. primor-
dium. We should not conclude, however, this mode of development

252 BOTANICAL GAZETTE [oCTOBER

is necessarily to be found in other plants until they have been studied,
though it is probable that it is true for at least some of the other
species of Agaricus (Psalliota). FAavop found that usually the pri-
mordium of the pileus was organized in the apex of the homogeneous
young carpophore before the appearance of the primordium of the
hymenium, and this seems to be true in certain species of Hypholoma
studied by one of my students. In fact Fayop asserts that this can
be accepted as a general law. The primordium of the pileus is the
first to appear in the organization of the parts of the carpophore
from its primordium. It is shown by the area of hyphae composing
it taking on a deeper stain in sections. It is in the form of an inverted
bow] convex above, concave below, and Agaricus rubellus (Psalliota
rubella) is one of the forms which he studied. The only exceptions
which he admits are the coriaceous forms like Lentinus (I. ¢., p. 296):
In this respect these cultivated forms of Agaricus campestris show
also an exception to this rule, and the primordium of the pileus is to
be regarded as diffuse in the primordium of the carpophore, as he
suggests for the coriaceous forms.

The question of the simultaneous organization of the pileus an A
stipe from a young homogeneous fruit body is an interesting one in
view of the different theories held by some of the earlier students.
Thus Fries”? said: “Omnia organa simul, nulla subevolutione nova
successive explicantur. Ommes extremitates ipsius Fungi explicatt
jam in aetate juvenili adsunt,” 7. e., ‘all organs are unfolded simul-
taneously, none by new successive development. All parts (or
extremities) of the unfolded fungus itself are already present the
young stage.” He thus believed that in the very young fruit body
the organs or parts, though rudimentary and invisible, were all present,
their manifestation and expression was a matter of unfolding.

This interesting conception is shown also in another place (I. ¢ 40),
where he expresses his view of the general mode of growth oe
fungi as compared with that of the algae as follows: “Fung! 1? geal:
plerumque directiones a centro, quod junius, sese expandunt, :
“Fungi, though young, expand from the center in almost all ee
tions.” All the parts being present, the growth in the center P™
them outward, as they enlarged, into their respective positions, W

20 E. Fries, Systema orbis vegetabilis, part 1, 40, 43-

1906] ATKINSON—AGARICUS CAMPESTRIS 253

the growth in the case of the algae was at the periphery—“ explicantur
ita, ut extremitates semper sint juniores”’ (J. c. 53).

Then as to the relative time, or priority of the shaping of the
different parts, Fries says (1. c. 44): “ Pileus v. c. in Agarico formatus
est prius quam stipes pronascitur. Stipes enim pilei, cum quo con-
tiguus, prolongatio et receptaculi pars,” 7. e., “the pileus, for example,
in Agaricus is formed before the stipe is produced. The stipe cer-
tainly is a prolongation of the pileus with which it is contiguous, and
part of the receptacle.”

J. Scumirz?! in his Mycologische Beobachtungen, as a result of
the study of several forms, holds an entirely different view. He
agrees that according to his own observations in many cases all parts
of the fungus are formed and present in a very young stage. But
he cannot understand, nor believe, that these parts are formed at
once, that is, simultaneously with the origin of the fruit body as if
by the touch of a fairy wand (“wie durch einen Zauberschlag,”
p. 174). That at certain young stages all parts are to be considered
present and yet invisible he regards as belonging to the domain of
pure speculation, a hypothesis suited to a philosophical mode of
Tepresentation or idealization, and not corresponding to reality.
SCHMITZ gives an account of his studies on Cantharellus sinuosus,
C. tubaeformis, Agaricus bulliardi Pers. (=Cortinarius bulliardt
[Pers.] Fr.), Coprinus niveus, and Hydnum repandum, and believes
he is justified in formulating for the pileate fungi a law of develop-
ment as follows: “1st, that a successive formation of single parts
or organs takes place; 2d, that this appearance of new parts rises
upward just as gradually as in the case of the higher plants,
in such a way that the higher standing parts naturally come to
view later than the lower parts, that the matrix or hypothallus
appears before the stipe, the stipe before the pileus, and the
pileus before the hymenium.??_ In Agaricus (Crepidotus) variabilis

2t Ueber die Bildung neuer Theile bei den Hymenomyceten, vorzugsweise den
Pileaten. Linnaea 16:168-179. 1842.

ees “Ich glaube also, dass man bei der Pileaten als Gesetz aufstellen darf, dass 1)
“ine successive Bildung der einzelen Theile oder Organe vor sich gehe; 2) dass dieses
Hervortreten der neuen Theile ebenso graduell aufwirts steige, wie bei den héhern
Pflanzen, so naimlich, dass die héherstehenden wesentlichen spater als die untern zum
Vorschein kommen, also die Matrix vor dem Stipes, dieser vor dem Pileus und der
letztere (an und fiir sich) vor dem Hymenium auftrete.”

264 BOTANICAL GAZETTE [ocroBER

OERSTED?’ says that the stem is produced first, and afterward the
pileus.

In the forms of Agaricus campestris studied here, as I have shown,
the young homogeneous fruit body (figs. 1, 2) shows no differentia-
tion into parts (except the rudimentary universal veil), and it is to
be considered as the primordium of the carpophore, It is not 4
stem, nor is it a pileus, there is no differentiation to show even the
rudiments or primordia of stem or pileus; there is no more active
growth manifest in one place than in another, and no separate group
of hyphae with richer protoplasmic content which gives a differen-
tial stain. It cannot therefore be considered as a rudimentary stem,
as GOEBEL (/, c, 132-138) has suggested. It is true we might speak
of a stem end and a pileus end, but the application of these terms to
the portions of the carpophore primordium which are later to be
organized into pileus and stem primordia does not predicate their
existence before organization takes place. But soon the differentia
tion takes place by the appearance of the primordium of the hymenium,
which at once delimits also the primordia of pileus, stipe, and ame:
ginal veil (figs. 3-5). This condition answers well to the conception
of Fries that all parts are present in the young stage, though he
conceived them to be present in the still younger stages, which we
find is not the case,

DECANDOLLE* says that in the case of Agaricus the upper A gs
or pileus develops before the lower part, or stipe. Without critical
study of the very young stages one might be led to this conclusion
by an examination of certain large pileate short-stemmed is
and perhaps DECANDOLLE examined such plants. According to
Fayop (I. c. 279-280) the pileus is differentiated first, the hymemum

23 OERSTED, A. S.: Iagttagelser anstillede i Lébet af Vinteren 1863-64, som cast
ledet til Opdagelsen af de hidtil ukjendte Befrugtningsorganer hos Blapsvampen®
Oversigt over det Kongelige danske Videnskabernes Selskabs Forhandlinget, P- a
pls. I-2. 1865. Copenhagen.

See translation, Observations made in the course of the winter 0
have led to the discovery of the hitherto unknown organs of fructification in the ¢
cini by A. S. OERSTED. Quart. Jour. Microscop. Sci. 8: 18-26. 1868. o

24 “Dans plusieurs, tels que les Agarics, la partie supérieure, qu’on ore”
chapeau, parait développée avant l’inférieure, qu’on a comparée & une tige 0 fs
pédoncle; l’inverse semble avoir lieu dans les Clavaires qui paraissent on
en haut.” Organographie végétale 1:384. 1827.

£ 1863-64, which

1906] ATKINSON—AGARICUS CAMPESTRIS 255

and stipe later, and it is interesting to note that W. G. SmirH?s in
his study of Coprinus radiatus says that the cells of the pileus and the
hairs which form the veil are the first to appear (/. c. 62), but his
study does not seem to have been exact, and a comparison of such
a form as Coprinus with Agaricus. (Psalliota) is not pertinent at
present except as it bears on the attempt of some to formulate a
general law of growth. oy

If we.now turn to the law formulated by Scumrrz for the order
of succession of the different parts of the pileate fungi, we see that
A garicus campesiris does not conform to it, but that it is more in
accordance with the idea expressed in the first sentence quoted from
Friks, that all parts of the fungus unfold simultaneously. This
must not, however, be taken wholly to support Fries’ conception
of the young sporocarp nor his idea of central growth. While it is
likely that a number of other fungi.will be found to agree with A gari-
cus campestris in the mode of organization of the parts of the plant
from the primordium of the sporocarp, it is certain that no law of
Organization and succession of the parts can be formulated which
will hold good of all the pileate fungi. There are probably some,
as suggested above, in which the pileus and stipe primordia are
organized before the primordium of the hymenium, and many others
probably in which the stem is partially or quite well organized before
there is even a primordium of the pileus, in which case the develop-
ment would be in conformity with Scurrz’s law given above. This
is very likely the case with certain long, slender-stemmed species of
Marasmius, of such plants as Polyporus lucidus Leys. (Ganoderma
lucida), and others. But we must wait until the different types have
been carefully studied from the very young stages in microtome
sections,

Fayop (I. c.), who studied a large number of Agaricaceae, formu-
lates the general law that the pileus is organized first within the young
Primordium as a pileogenous layer (couche piléogéne), which arises
by internal differentiation, marked by the more rapid growth of the
hyphal elements and their richer content in protoplasm. This layer
1S in the form of a shallow inverted bowl, convex above, concave
below. This is surrounded on the sides and above by a thin layer

5 Reproduction in Coprinus radiatus. Grevillea 4:53-65. pls. 54-61. 1875.

256 BOTANICAL GAZETTE [ocroBER

which he calls the primordial cuticle (cuticle primordiale), From
his description the primordial cuticle varies in character and probably
in structure also, and it is difficult to accept his conception of a pri-
mordial cuticle as a homologous structure in the large series of forms
to which he applies the term. For example, he recognizes three
main types in the development of the Agaricaceae: rst, the gymno-
carpous forms; 2d, the angiocarpous forms; 3d, the endocarpous
forms, and the primordial cuticle is present in all except in a very
few of the gymnocarpous forms. In the gymnocarpous forms the
primordial cuticle consists generally of a more dense layer of tissue
underneath which the pileogenous layer is formed. The margin of
this becomes the border of the pileus, and as it extends laterally it
dislocates at this point the primordial cuticle, so that the primordium
of the hymenium which now arises is of exogenous origin, thus giving
rise to the gymnocarpous type. Examples are Panus stipticus,
Cantharellus cibarius, Marasmius rotula, Collybia racemosa, etc.
Thus while DeBary believed the pileus in the gymnocarpous forms
originated exogenously, Fayop holds that it originates endogenously;
but in discussing farther certain other forms he admits that the pileus is
formed in the manner indicated by DeBary, and he states that the
discussion which he has raised here is more in regard to a principle
than fact, and he would not have raised the question at all had it
not been for the fact that his study of the angiocarpous forms had
shown him the importance of the pileogenous layer.
In many of the angiocarpous forms the primordial
seem from his own description to be a different structure
it is in the gymnocarpous forms, for he says: “The hyphae which
emanate from the pileogenous layer do not reach the surface of the
primordium. Asa consequence the primordial cuticle, which acquires
here a very considerable thickness, preserves its integrity and con
tinues to increase up to the time of the formation of the jamellae
and stipe, that is, up to the second period of development.” ss
he recognizes the primordial cuticle as identical with the univers?
veil, and he would call it general veil (voile général), although it é
often formed in some cases by parts also of the subjacent tissu :
the primordium, were it not for the fact that he wishes to plat :
in the same category as the non-integral element of the primordium

cuticle would
from what

1906] ATKINSON—AGARICUS CAMPESTRIS 257

in the gymnocarpous forms which he considers a primordial
cuticle.

The angiocarpous forms he further divides into two types, sub-
angiocarpous and angiocarpous. In the subangiocarpous type the
universal ‘veil (cuticule primordiale), being continuous over the pileus
and stem, forms the veil which is known as the “ partial veil” or
“marginal veil” of authors. He says (p. 286) it is probably charac-
teristic of Flammula, Inocybe, Dermocybe, Hygrocybe, Psalliota,
Lepiota, Psathyrella, Coprinus, and most of the Tricholomae. In
the true angiocarpous types there is a cuticle of the pileus which is
organized underneath the primordial cuticle or universal veil, so that
at maturity the universal veil separates and forms floccose patches,
or a volva, or may disappear by gelatinization. As examples he
cites Agrocybe (Pholiota praecox, Naucoria semiorbicularis, etc.),
Pholiotina (Pholiota blattaria, P. togularis, etc.), Rozites Karsten
(Pholiota caperata), Nemataloma Karsten, some species of Panaeolus,
Telamonia, and probably Locellina and Chitonia; the volva in the
last three genera he considers to be only a very thick universal veil.

In the endocarpous forms the primordium of the fruit body is
differentiated on the interior of a primitive bulb which he calls the
primordial bulb (bulbe primordial), to which belong the greater num-
ber of species of Amanita, Volvaria, and some species of Phlegmacium.
Since this type does not concern us here it will not be in place to
discuss it,

From the foregoing it is seen that Fayop places Psalliota (which
includes A garicus campestris) in his type of subangiocarpous forms.
Among these forms he studied A garicus rubellus Gillet (Psalliota
rubella). While he does not describe the development of this species
(his discussions of development are in the form of general conclusions),
he says that it belongs to the subangiocarpous type, and his jig. 4,
pl. 7, shows the primordial cuticle to consist of rather loose radiating
threads connected on the sides where it extends down over the lamellae
and stipe with the thicker portion covering the stem. Although
Fayop placed A garicus campestris also in his subangiocarpous type,
a study of these cultivated forms shows that it would belong to his
true angiocarpous type because of the free universal veil entirely
independent of the marginal veil, the universal veil eventually sepa-

258 BOTANICAL GAZETTE [OCTOBER

rating into floccose patches on the surface of the pileus as in Roziles
caperata (Pers.) Karsten (Pholiota caperata Pers.).
During the later period of growth and the beginning of elongation
of the plant, the marginal veil increases in thickness and extent. It
_is entirely free from the lamellae, the hymenial cavity being quite
distinct from the first and becoming greater by the expansion of the
pileus and marginal veil, and also by the elongation of the portion
of the stem above its attachment. The increase in the surface extent
of the marginal veil is considerable and results in throwing the uppet
surface into radiate folds which are quite noticeable, especially in
the well developed individuals. In the young primordium at the
time of the organization of the parts of the carpophore the marginal
veil is attached over a large part of the outer surface of the stem
primordium, the lower end, perhaps that portion which corresponds
to the bulb in other species, being free. It thus remains attached
over the stem surface for a considerable period during growth, 4s
the period of elongation advances, the veil begins to separate from
the stem at the lower end and is gradually torn off and upward as
the pileus expands and the stem elongates. The tension of the con-
necting fibers can very easily be seen between the stem and the under
surface of the veil, and is well shown in fig. 20. It therefore forms
a sheath over the stem except a short section of the lower end, and
the portion above the marginal veil which is elongating. 1
sheath is loosened from below upward except at the upper point at
attachment to the stem. The outer margin of the veil is attached
to the rounded and thick margin of the pileus, and being of consider-
able thickness in these cultivated forms the lower edge of the veil 15
separated first from the outer surface of the pileus margin (fig. e
and the inner upper edge is separated last from the inner surface 0
the pileus margin. The margin of the veil is therefore furrowed (figs.
18, 19). A thick marginal veil of this type is called a “ double veil,
a type which is very characteristic of certain other species of Agaricus
where it is more highly developed, especially in Agaricus _
where the lower portion of the veil splits radially. It is very stl le
in Agaricus rodmani Pk., where the forking of the veil extends coma
to the stem.*° In Agaricus placomyces Pk. the veil is often similar to
26 See jig. 17, ATKINSON, Studies of American fungi, mushrooms, edible, poiso™”
ous, etc. 1900, Igor, Ithaca; 1903, New York.

1906] ATKINSON—AGARICUS CAMPESTRIS 259

that of Agaricus arvensis (figs. 21, 22 in Studies Am. fungi, etc.),
while in Agaricus silvicola and others the lower half of the marginal
veil is often separated into patches (l. c. fig. 20). In the pasture
or field forms of Agaricus campestris the marginal veil is thinner,
but even here its double character is often manifest (fig. 7, /. c.).

The growth of the pileus which at first is strongly hyponastic
becomes less so as the pileus expands. The upper surface gradually
ceases to grow and the extension of the underlying part often tears
the pileus cuticle into fibrous scales. The growth of the pileus
gradually becomes epinastic, as the lower area and the hymenophore
with the gills now grow more rapidly than the middle and upper
portions, This causes the pileus to become plane, or in old speci-
mens the margin itself becomes upturned. This peculiarity in the
growth of the Agaricaceae during the period of elongation was sup-
posed by some of the earlier botanists?? to be due to the influence
of light, for it was thought by them to be necessary that the hymenium
should be turned up to the light. We now know that light is not
necessary for the growth and ripening of many species. This partial
eversion of the pileus in many species unquestionably serves a useful
purpose in providing for the wider distribution of the spores, for
they are more easily caught by currents of air as they leave the
hymenium,

The order in which elongation of the different parts takes
place is thus different from the order of their initiation in the young
primordium, As has been shown in these cultivated forms of A gari-
cus campestris, the organization of the primordia of pileus, stem,
hymenium, and marginal veil is practically simultaneous by the
appearance of the hymenial primordium as an internal annular area;
while the organization of the parts gradually proceeds and is also
simultaneous to a certain degree. But the period of elongation of
the parts after they have become organized, while overlapping to a
certain extent, follows in succession. The marginal veil completes
its period of elongation first, then the stem, followed by the pileus,
and finally the hymenium.

_ One striking feature of the hymenium of these cultivated forms
is that, so far as I have examined (the varieties Columbia, Alaska,

27 See NEES VON ESENBECK, Das System der Pilze und Schwamme 179-187. 1816.

260 BOTANICAL GAZETTE [OCTOBER

Bohemia, and others), the basidia are two-spored. I have several
times observed this fact in the cultivated mushroom. The illustra-
tion of the hymenium of Agaricus campestris which I have used on
two former occasions?® was made from a cultivated variety. GOE-
BEL’s fig. go? shows only two spores on the basidium of Agaricus
campestris, and this was probably also made from a cultivated variety.
I have on the other hand several times observed that in case of the
normal field or pasture form of Agaricus campestris there are four
spores on a basidium. The nuclear phenomena in the formation
of the spores have not yet been thoroughly worked out in the two
spored forms of Agaricus campestris, but studies of C. E. LewIs
carried on in my laboratory seem to show that the normal number
of four nuclei are first formed in the basidium, and that two of them
degenerate. This has been very. clearly shown by him to be the
case in a new species of Amanita, A. bisporigera Atkinson.*° Nor
has it been shown how the two-spored forms of A garicus campestris
arise from the normal four-spored feral plant, or whether normal
two-spored forms exist as constant types ia the field under natural
conditions of environment, I have found a two-spored Agaricus
resembling in some respects certain of the cultivated forms of
Agaricus campestris growing spontaneously in the open, On one
occasion it was found in June about young trees in a lawn which had
been mulched with horse manure. On another occasion the same
species was found on the hillside of a wooded ravine (Cascadill F
gorge) on the campus of Cornell University.

If there are two-spored forms of Agaricus campestris existing under
natural conditions of environment which are constant and which
present also other characters even slightly different, it would indi-
cate that Agaricus campestris either is or recently has been passing
through a mutating period, and that these forms are elementary
species. Were the two-spored basidia the only differentiating char-
acter, such a form might in the sense of DeVrres** be reg@ oa

28 Studies and illustrations of mushrooms. I. Cornell Univ. Agr. Exp. Si®
Bull. 168. fig. 189. 1897; and Studies of Am. fungi, etc. (/.)

29 Outlines of classification and special morphology, Eng: ed., 1887.

3° Lewis, C. E., The development of the spores in Amanita bisporigera
Bor. Gaz. 41: 348-352. 1906.

3¢ Species and varieties, their origin by mutation. 1905.

Atkinson.

re rT?

1906] ATKINSON—AGARICUS CAMPESTRIS 261

a variety, for it would seem that the four-spored quality or character
is latent, since four nuclei are probably formed in the basidium in
the normal manner but only two of them function. With regard to
the cultivated forms of Agaricus campestris they probably represent
also mutations either from Agaricus campestris or from some other
species which has been confounded with it. Whether they are to
be considered elementary species or varieties or retrograde varieties
would depend upon their constancy or inconstancy, their stability
or instability. They may be horticultural or domesticated varieties.
Nevertheless it would seem that they have arisen by mutation. It
is interesting to note in this connection that, whether species or
varieties, if they have arisen by mutation their chances of becoming
constant may be greater than in the case of plants which are well
known to reproduce sexually. It is generally believed that the
Agaricaceae are not reproduced by the cooperation of sexual organs.
If,this is true, and if there is no process similar to fertilization, muta-
tions of these plants would escape one of the operations in nature
against the constancy of new mutants in species capable of cross

fertilization, Some students regard the fusion of the two primary

nuclei in the basidium as an act of fertilization, but from what we

know of the origin of these two nuclei the possibility of cross fertili-

zation of individuals at this epoch of development is excluded, though
it cannot at present be regarded as impossible at an earlier stage in
their ontogeny. Of course the earlier ideas of fertilization in the
Agaricaceae held in the time of BULLIARD,3? who called the cystidia
spermatic vessels and thought they squirted their juices on the seeds
(Spores) thus bringing about fertilization, or by Corpa33 who regarded
the cystidia as pollinaria and thought fertilization was brought about
by the exudation of their fluid content to which the spores became
attached and fertilized, are now unthinkable, as well as the notion
of W. G. SurrH34 as late as 1875, who believed that filaments growing
out from the cystidia came in contact with the spores and fertilized

32 BULLIARD, Histoire des champignons de la France 1: 39-66. 1791.

33 CorDA, Berich. Ises. 6:40. 1834; also Icones 3:44. 1839. See also H. Horr-
eae eta und Spermatien bei Agaricus. Bot. Zeit. 14:137-148, 153-163-

34 Situ, W. G., Reproduction in Coprinus radiatus. Grevillea 4:53-65. pls..
54-61. 1875. :

262 BOTANICAL GAZETTE [OCTOBER

them, and that hybrids between species were very commonly found
where cystidia and spores from adjacent species fell to the ground,
commingled, and brought about cross fertilization. But the last
word may not yet have been said with reference to the possibility of
a fertilization prior to or during the early stages of the organization
of the primordium of the carpophore, like that proposed by OERSTED
(l. c.) for Agaricus (Crepidotus) variabilis, or in some closely related
manner.

However, the propagation of forms by spawn which is not obtained
from the spores, as is practiced by DuccGar,35 would seem to be
equivalent to vegetative propagation or budding, and thus might be
of advantage in maintaining constancy in varieties, since they would
not be subject to cross fertilization, though it is still a question if
fertilization and cross fertilization take place in the Agaricaceae.
If it does not, or if some process equivalent to it, especially cross fer-
tilization, does not take place, the Agaricaceae, and in fact the
Hymeniales, would be especially free from the production of hybrids,
and the constancy of species or varieties arising by mutation would
be correspondingly favored. In a numberof species there are indica-"
tions that mutation is now going on, or that these species have recently
passed through a period of mutation, and some of these apparent
mutants appear to be quite constant, On the other hand, there ar
many species which show great fluctuating variability due to varying
conditions of food supply, moisture, substratum, etc.

CoRNELL UNIVERSITY,
t x.

DESCRIPTION OF PLATES VII-XI.
Photomicrographs with Zeiss microscope except fig. II; plate holder
from object on slide; photomicrographs and photographs by the author.
PLATE VII.

360™

. m
Fic. 1. Young carpophore, var. Alaska, undifferentiated; oc. 2, obj. 16°"

Fic. 2. Same as fig. 1, but with oc. 4, obj. 16™™. aia tek

Fic. 3. Young carpophore, var. Columbia, with primordium of hymenium
earliest stages of endogenous origin; oc. 2, obj. 16™™.

35 Duccar, B. M., The principles of mushroom growing and mushroom? ne
making. U.S. Dept. of Agr., Bureau of Plant Industry, Bull. 85. PP- go. Ps:
1905.

1906] ATKINSON—AGARICUS CAMPESTRIS 263

Fic. 4. Young carpophore, var. Alaska, with endogenous primordium of
hymenium a little more advanced than in fig. 3; anyones veil distinct as a loose
definite layer of tissue surrounding the carpophore; oc. 2, obj. 16™™.

Fic. 5. Young carpophore, var. Columbia, Bae ee endogenous primordium
of hymenium a little more advanced than in fig. 4; universal Mas as a very thin
layer; oc. 2; obj. 16™

PLATE VIII,

Fic. 6. From young carpophore, var. Columbia; at stage when gill slit is
just forming, showing sharp-pointed threads of primordium of hymenium pro
jecting downward; also shows at the right the thin layer of universal veil; about
same gee as fig. 7, but not with Zeiss microscope.

1G. 7. Same object as fig. 6, but showing only the gill slit and primordium
of bismacicn:

Fic. 8. Same as figs. 6, 7, but more highly magnified; oc. 6, obj. 3™™.

PLATE IX.

Fic. 9. Young carpophore, var. Alaska, showing endogenous primordium of
hymenium on le side, about the same stage as fig. 4, but higher magnification;
9c. 4, obj. 1

FIG. to. a carpophore, var. Alaska, with endogenous primordium
more advanced, showing definite and clear opening, the descending threads of
the primordium of the lamellae, loose tissue of the inner veil, and primordium
of stem cortex, outlined as an oblique area of younger threads rich in fee
extending from opening obliquely downward and outward; oc. 6, 0

1G. 11. Portion of young carpophore, var. Columbia, yi gill slit;
young lamellae in longitudinal section, inner veil of more open loose tissue;
shows also how primordium of hymenium continues in its development as mar-
gin of pileus continues to grow; cortex of stem well-formed, showing as a more
Compact tissue over the surface to which the veil is attached; oc. 4, obj. 16™™.

Fic. 12. Portion of young carpophore same age as fig. rz and from same
plant, but cut somewhat obliquely so that a number of gills are shown in eo
Section, otherwise as in fig. 11, but with less magnification; oc. 2, obj. 16™™

PLATE X.

Fic 13. Cluster of young carpophore, var. Columbia; numerous very young
ones, several in the large button stage, showing the small white patches of the
universal veil on the brown cuticle of the pileus.

Fic. 14. Another cluster of young carpophores, 1 var. Columbia, showing nu-
merous very small ones, and several of the small button stage, the universal veil
Separated into a few large white thin patches; rhizomorphs in the substratum.

PLATE XI.
Fic. 15. Longitudinal section of young carpophores magnified twice the real
length, showi ing endogenous primordium of hymenium, gill slits, veil, and the
primordium of cortex of stems.

264 BOTANICAL GAZETTE [ocroBE

Fic. 16. Real size; young carpophores, var. Columbia, showing r rhizomorphs,
the expanding young pileus and universal veil separated into patches; it is very
distinct in the two plants where the universal veil is stretched between the two
caps; at the right a few in longitudinal section.

Fic. 17. Young carpophore, var. Columbia, about half grown, real he:
showing a few white patches of universal veil on the pileus, about midway of
the short stem showing a ring which is the lower part of the double ring; in
this case separated from the upper part and remaining on the stem as a distinct
ring as in Agaricus rodmani; upper portion of the veil still attached from stem
to margin of pileus which is as yet close against the stem.

PLATE XI. é

Fic. 18. Cluster of mature carpophores of A cam pestets; cult.

showing patches of universal veil on pileus.

1G. 19. Mature and nearly mature plants, var. Columbia, showing ¢

veil which forms a sterile margin on the edge of the pileus anda thick ring W

or corrugated on the upper surface and the edge distinctiy double.

Fic. 20. Slightly younger stage, also lower part of double veil as | Dn

away from the outer surface of margin of pileus; upper part of double veil
attached to margin of pileus.

The material was selected and fixed in chromo-acetic acid by myself,

I am under many obligations to Dr. CHARLES E. Lewis, who then took

material, carried it into paraffin, sectioned, and stained it. :

AGARICUS

ATKINSON

BOTANICAL GAZETTE, XLII PLATE Vill

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ROLE OF SEED COATS IN DELAYED GERMINATION.
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY.

WILLIAM CROCKER.
(WITH FOUR FIGURES)
I. Historical.

Ir is well known that in many species of plants not all the seeds
of a given crop germinate promptly after being subjected to so-called
germination conditions; instead they germinate at irregular inter-
vals through a period of weeks, months, or even years. It happens
in many species that none of the seeds of a crop will germinate until
they have been subjected to germinative conditions for a year or
more, and that in these cases of marked delay germination is dis-
tributed through a further period of greater or less length.

Delayed germination is well illustrated in the results of the
researches of NoBBE and HANLEIN (8, a, b). Table I shows their

observations on thirty-one species of common weeds, They began
With 4oo seeds of each species and continued their experiments 1,173
days,

Krenitz (4) found marked distribution in the germination of
crops of the beech, white fir, ash, hornbean, and pine; and WINKLER
(15) in sowings of Euphorbia cyparissias, E. exigua, Cuscuta, etc.
WIESNER (14) found that the seeds of Viscum album germinate only
sparingly in the fall after ripening, but readily the following spring.
Kuntze (6) in reviewing the literature on germination mentions a
large number of cases of delayed germination. The hawthorn, he
states, will grow only after being in the ground one to three years.

One of the most interesting cases of delayed germination is that
of the cocklebur (Xanthium) reported by ARTHUR (Ty. ac found
that the two seeds in the bur are not the exact counterparts of each
other, but can be distinguished readily by their form and position in
the bur. One seed, which he terms the upper because it is borne
nearer the apical end of the bur, is convex on the outer face and con-
265] [Botanical Gazette, vol. 42

TABLE I.
ArtER NoBBE AND HANLEIN; 400 SEEDS OF EACH SPECIES.

Name/No. of seeds germinated on day 54:6 7 8 9 | 10] 16 | 36] 72|r45 \35x| 519 | 714 | 874 | 1082 | 1173 | Total | Per ct.

1 Aquilegia vulgaris ...............|.- Me ke Sa de eo 3 . TG ie GN Be AR ae aries | ee eo 0.75
2 Campanula rotundifolia OL SE aa A oid ig 8 A, a a rl Be ee al Be voleitob 122) to Tey 58 | 14.50
3 Campanula persicifolia........... OR |e She 3 8 |14| 112 | 56] 1 wT. 8 2 8 2 6 | 232 | 58.00
ampanula Trachelium.......... aS UR Pe ak Re, PS Ss ee aR ats ae A ate ae re oe I 0.25

5 Chaerophyllum temulum......... ee Ati Bs, OE) ea ar ee > pagar a : : i: 3 3 0.75
nopodium album............. ee fe ie le ha) 2 1/19/53| 27 ; ai) 30 aol 33 oe. Wagae

Z Capsella Bursa-pastoris.......... A Oe Re ye ee ee gue aa J: Poet Ba eG we ect. 24. IO ri ae poten tea As
Chelidonium majus..........++.+} +. Fe Nia he Se ds i bin ee Ae ol oes 4 S| oe ee Pe ees 3 | go i} geil rose: | 48.78

9 Digitalis purpurea...........--.. go Oo. as \x02 $47} 150 124)..7 1s. sore, ts. | test | ‘ecalyed | 387-90. 75
1o Hypericum hirsutum............. bisat- I 4 F213) 1421 58) «. rear |: Pe rete ee ie he ere
{1 Ficum mMontanum..........|.; meas 4a 6 1 Gar) 171 4G). : : Bers oy vas a oeeee ee oe
12 Hypericum perforatum .......... wa Shoes TA el tee | tO 1-289 ie I Toil Sars 58 | 14.5°
3 fie MIOMIADG cy vee ae re ee S174 Ga tae | Bt P30! BBY ale. (6 eee ia | os) nest | decatyed | 997: 09-45
14 Lithospermum arvense........... ¥2 | 32°30 1-sa } f8°)) & | 521 42) 28 |: ean re | 22 6 | rest | decalyed | 344 | 86.00
15 Lysimachia vulgaris............. aa SEARS a | as Sy Sal | Oa Ma re Me eg Bee 7 Mesa Pass ot aes I 0.25
16 OSUTUS TOIDIMUS ay iach. as bs fs ALTO P100 HerOe TON 2] eh [|r TPpeae Pe 21 347>. 1280.75
cpeaus cornirulata. fs css ace ess a ae EN age <i Sak let A A Re eg Ce eS gage 2 , I 3.00

oo Peoaver Argemone:,..:....5-.-:|.> ait S&S Gs far6 | 76; 8) 34 1 30)TS | 44201 87 z 336 | 84.00
= Peoaver dublum 22... .....-.. .. | 2] 216 | 169 ee ee a ae es 388 | 97.00
See spicetan sv a es ob cae fee pee Te ‘s chee eae we a A OF 1s 6.06
- ap lai Be Se eae rer FN eget Real | ta SI os Fee ee ee re 6 ESE nae are I I 0.25
Oe mings Wiedia... ik ss. 48) 3 4 Bee et eas 1 elegy 9 I 6 2 43 tones
23 Polygonum persicaris Paras Goel. B38 | els Silecec. Hig sf See Reiter re dart S5e arses
24 Me SSUES ts sk. a ice ates ee ae Cooes ye (eo pain Rings SP safe Way aleve ieaeaivad ican app Oo 0.00
an Owns argentea. 2 cies.) +286] SER he Soe OF hO) Ga see S13 3 3 2 7 | 301 75.25
26 Scrophularia nodosa.............|. ri. Sh Oe) 90 faz) 4754 pct a Be 7 sake ls 99 Tee eS oes
OP 1 mine! Gipestte 0.6565. vst. i oh ts at iia aces a ee ay ely) Gecaiyed |... |. 3. fe) 0.00
Oe Lialaspl aryense. 5646s oe : Me Ue We era Beton arial TTA) ES Se) B87 gala lere
29 Verbascum nigrum ..............|- eh A SOT Ferrel On cert | areal po Ses Pee Aad a Te) .00
30 Veronica Beccabunga...........-|- ph SS Sg Tels ot) et Ome eg me | TOS |. Aah evapie 83. | 45.75
31 Veronica officinalis .............5|. BSG soar 41% foeenbegt tes cel cer rest | decalyed | 396 | 99.00

99%

ALLAZVI IVOINVLO

waag0.LI0}

1906] CROCKER—DELAYED GERMINATION 267

cave on the inner. The lower seed, lying nearer the base of the bur,
is concave on the outer face and convex on the inner, ARTHUR
found that plantings of burs of the cocklebur (mainly Xanthium
canadense) in a garden bed resulted in
the germination of all the lower seeds
in the first year after ripening, and
of only a very small per cent. of the
upper seeds, The second year a
teat majority of the upper seeds
grew. A few of the upper ones, how-
ever, grew in the third and fourth years.

MAasTERMAN (7) claims that both
seeds grow the first year after they
are planted. His methods, however,
Were not at all adapted for detecting
whether the two seeds of the bur have
markedly different germinative char-
acters. Both Arruur’s work and
the experimental results of this paper Fic. 1.—Cocklebur cut away to
show that such differences in the ger- show upper and lower (dimorphic)
minative characters undoubtedly exist. —

Delayed germination was found by Nopse and HANLEIN to be
due in many cases to the impermeability of the seed coat to water.
As to the seeds listed in Table I, however, they say that in every
case the seeds absorbed the water readily and yet lay in the germi-
nator in a saturated condition for long periods, either not germinating
at all or scattering their germination over a long period. They main-
tain that in cases where water is admitted the growth after long
“Xposure to germinative conditions must be due to some change going
on within the embryo during the period of rest. WINKLER (15),
WIESNER (14), Krenirz (4), and Prerrer (9) expressed similar
views,

ARTHUR found that both seeds of the cocklebur take up water
Teadily while in the bur. The bur, therefore, does not account for
the delay. He also believes that the extremely delicate seed coats
‘re in no way different in the two seeds and that the structure of the
Seeds, therefore, offers no explanation of their germinative difference.

268 BOTANICAL GAZETTE [OCTOBER

He suggests that enzymes are produced readily in the lower seeds
and that, therefore, they have foods at hand to begin their growth
immediately; whereas the upper seeds are able to develop digestive
ferments only after a long period of rest, and hence their germina-
tion is delayed one or more years. This theory has its experimental
basis in the fact that if both sorts of seeds are exposed to germinative
conditions for some time the lower ones show much reducing sugar,
while the upper ones have only a trace. My interest in this problem
was aroused by ArrHur’s paper on the cocklebur, and the work
was begun for the purpose of testing this enzyme theory and deter-
mining definitely the cause of the delayed germination of the upper
seed,
II. Materials and methods.

Most of the germinative tests reported in this paper were made
between moist filter papers, but in all these cases corresponding tests
with very similar results were made in fine quartz sand and in garden
soil. For Avena fatua, Iris, and cocklebur seeds in the bur, all tests
were made in sand and garden soil on account of the great liability
of these structures to be attacked by fungi.

Five species of cocklebur were used: Xanthium canadense Mill.,
X. echinatum Murr., X. glabratum (DC.) Britton, X. glandulijerum
Greene, and X. speciosum Kearney. In each species similar
conditions gave similar results whether the seeds were in the bur or
removed from it; but for convenience in handling and accuracy of the
records the seeds were generally removed from the bur. For testing
increased oxygen pressures the soaked seeds were allowed to rest 0m
the walls of flasks containing oxygen or (in the checks) air. Germ
native tests at high temperatures were made in ordinary paraffin ovens
regulated to the desired temperature. The effect of temperature 07
the rate of diffusion of oxygen through the seed coats of the cocklebur
was determined in a large water bath (such as is used in chemical
laboratories for determining solubility, etc.) regulated to 0.01".

The seeds used were collected when thoroughly ripe from various
parts of the United States and Europe,’ stored in a dry room, 4?
used in experimentation within six months after collected. since
a year of dry storage and the region from which the seeds were

«Iam indebted to M. P. Dreuponné for collections from Belgium.

1906] CROCKER—DELAYED GERMINATION 269

gathered gave no marked germinative variations in the species used,
the time of storage and the region in which they were collected need
no further consideration. A seed was considered germinated when
root hairs appeared, except in Xanthium and Iris, where late develop-
ment of root hairs made this test worthless and the lengthening of
the radicle 5™™ was considered the criterion of germination.

- III. Experiments.
I, COCKLEBUR.

Effect of enzymes——When work was begun on the seeds of the

cocklebur, ARTHUR’s enzyme theory was adopted as a working hypo-
thesis, on the supposition that it would involve a study of the differ-
ence in the development and action of the enzymes in the two seeds.
As WaucH (13), STONE (10), and THompson (11) were able to
increase markedly the germination of old seeds by soaking them in
solutions of various enzymes, it was thought that perhaps the upper
seeds of the cocklebur could be made to germinate without delay
by merely soaking them in solutions of pepsin, or plant trypsin, or
in filtered extracts from the germinated lower seeds. Experiments
in this line gave only negative results, but led to the discovery that
high temperatures cause the immediate germination of some of the
upper seeds, The enzyme theory was abandoned after failures to
detect any differences in the digestive activities of extracts of the
upper and lower seeds, At this point the results showed that the
difference in the germinative characters of the two seeds had other
causes; hence a new line of experiments was begun.
; Effect of high temperatures.—High temperatures bring about the
immediate germination of the upper seeds of X. echinatum. Table
II shows the results of temperature experiments with this species.
Results were similar whether soil or filter paper was used for germi-
nators and whether the seeds were in the burs or removed from
them,

As Table IT shows, the lower seeds of X. echinatum germinate .
readily at 22-24° but even more readily at 32-34°. The upper seeds
do not germinate at all at 22-24°, but respond readily at 32-34°.
The lowest temperature at which any considerable per cent. of the
upper seeds grow is at 33°, and the similar point for the lower seeds

270 BOTANICAL GAZETTE [OCTOBER

TABLE II (X. echinatum).

PER CENT. GERMINATED AFTER
Temp. °C, SEEDS
1 day 2 days 5 days 8 days
Zoe 5, Gaara Sea upper ° fe) ° oO
lower 3 31 87 99
5 Var Pe upper 8 55 99 99
lower 23 100 100 100

is 23°. In X. canadense, X. glabratum, and X. speciosum the upper
seeds germinate only sparingly at a constant temperature of 35°, but
to a considerably larger per cent. at a temperature fluctuating between
25 and 40°. The lower seeds of X. canadense germinate readily at
18-21°, while the lower seeds of X. glabratum have a minimum
germinative temperature of about 23°. The highest minimum ger-
minative temperature yet reported, 15.6-18.5°, is recorded by
DeETMER (2) for the cucumber and watermelon.

From the above data it may be seen that in the cocklebur there
are remarkably high minimum germinative temperatures. *-
echinatum, the least remarkable of the four species studied in this
respect, has this critical temperature 15° higher in the upper seed and
5° higher in the lower one than that of the watermelon and cucumber.

Effect of wounding. —In removing seeds from the burs the knife
often clipped off a small portion of the distal ends of the cotyledons.
It was observed that the upper seeds so wounded begin a marked
growth in the wounded region even at the temperature of 20-22°..
The growth gradually moves down the cotyledons until it reaches.
the radicle. This reverses the normal method of germination. Nor-
mally the radicle first pushes out, sets itself in the ground, and lifts.
the cotyledons above the soil, after which they begin their growth.
When the upper seeds are wounded at the radicle end, either by a
slight cut or a pin prick, germination takes place in the normal way-
This observation suggested complete removal of the seed coat.

Effect of removing the seed coat,—After the seeds have been soaked
six hours the extremely delicate seed coats can be removed, without
the least injury to the embryo, by merely pinching the seed between.
thumb and finger. The coat-free upper and lower seeds of any one of
the four species studied germinate with almost equal readiness at ay

1906] CROCKER—DELAYED GERMINATION . 271
point within their temperature limits, and the two seeds have almost
identical temperature limits. Table III shows the relative speed of

TABLE III.
X. canadense; COATS REMOVED; TEMP. 18-22°.

PER CENT. GERMINATED AFTER

SEEDS
3 days | 4 days 6 days | 9 days
Uppers ce 47 75 84 100
EOWEt ces: 51 vies 89 pice

germination of the upper and lower seeds of X. canadense at 18-22°.
The minimum germinative temperature for the upper and lower
seeds of this species with the seed coats removed is about 18°. The
same point for other species mentioned is 2~3° higher. Each seed
of Xanthium has then two minimum germinative temperatures: one
with the seed coat intact, and a lower one with the seed coat removed.
In the upper seeds these two temperatures differ by fifteen or more
degrees and in the lower ones by two or more degrees. Table IV
gives the approximate germinative minimum temperatures for each

TABLE IV.
MINIMUM GERMINATIVE TEMPERATURES.

i ini . °C. coats | Minimum temp. °C,
a Seeds re Besson coats removed
X. canadense......... 2. be fluctuating 25-41
ower 2I
X. echinatum.. . upper 32-33 19-20
A ae lower 23 19-20
me Pabratum: 205 sc tte fluctuating 25-41 -
ower
X. speciosum Sia sae byt sie fluctuating 25-41 oe
ower 22

of the four species with seed coats intact and seed coats removed.
It is evident from the results so far given that ARTHUR’S statement
that the difference between the two seeds does not lie external to the
embryo, but in the embryos themselves, is entirely wrong. He over-
looked the real point of difference, the seed coats, because of their
aS delicacy and because of the ease with which they admit
ater,

272 BOTANICAL GAZETTE [OCTOBER

Effect of increased oxygen pressures.—Since the delay is secured
by the seed coat, it must exclude either water or oxygen. As ARTHUR
states, both seeds seem to take up water with equal readiness. I found
that in eighteen hours of soaking, the upper seeds of X. canadense im-
bibed 51 per cent. of their dry weight, wliile the lower ones imbibed 62
per cent. In the same time the upper seeds of X. echinatum imbibed
48 per cent. and the lower ones 47 per cent. The difference then
in water imbibition will not serve to explain the difference in the
germinative characters of the two seeds.

It was found best in testing increased oxygen pressures to soak
the seeds 12-18 hours and then allow them to stick to the walls of a
flask or bottle containing the oxygen or (in the check) air. After
being thus treated and kept at 21-23° for six days, the upper seeds
of X. canadense gave too per cent. of germination in pure oxygen
and o per cent. in air. The growth in the seeds germinated in oxygen
at these relatively low temperatures does not take place in the normal
way. It begins in the distal
region of the cotyledons and
works down toward the
radicle, as was described
for seeds wounded at the
distal end of the cotyledons.
This peculiarity seems 10
be related to the structural
character of the seed coat.

The seed coat consists
of three distinct layers

Fic. 2.—Cross section of the seed coat of (fig. 2). The outer layer con-
Xanthium, showing the three layers. sists of shell-like cell walls

which are more and more
collapsed as the inner portion of the layer is-approached. This layer
is traversed by several groups of tracheae which are parallel with
the long axis of the seed. The middle layer is very dense, apparently
consisting of collapsed cell walls and staining very deeply with saf
franin, The inner layer consists of 1-5 layers of cells containing
protoplasm and nuclei. Each layer is thickest at the radicle end
and gradually becomes thinner toward the distal end of the cotyledons.

1906] CROCKER—DELAYED GERMINATION 273

The measurements of the three layers are approximately as follows:
the outer layer, at the radicle end 100 », at the distal end 20 #; the
middle layer, at the radicle end 15 p», at the distal end 8 »; the inner
layer, at the radicle end 30, at the distal end 4. The middle
layer is somewhat thicker in the upper than in the lower seed. In
both seeds it is less dense at the distal end. It seems probable that
the denser middle layer is only partly permeable to oxygen, less so
in the upper than in the lower seed, and less so at the distal than at
the radicle end. This accounts for the increased oxygen pressure
initiating the growth at the distal end.

Gaseous exchanges in res piration—The two sets of experiments on
the gaseous exchanges of the seeds in respiration throw some light
on the effect of the seed coats, The first set, reported in Table V,
a. of the oxygen taken up with the seed coats removed
esha up with the seed coats intact. Only the ratios can be
1 eagle ere, for different weights of seeds were used in the four

eterminations. These measurements were made with
eudiometers,

r TABLE V.
ABs ue
ORPTION OF OXYGEN; SEED COATS INTACT AND REMOVED; TEMP. 23°. [>
Cc. OF OXYGEN
Ratio oF I to IT
SEEps UsEp ee TAKEN UP AFTER
‘., 6 hrs. | 22 hrs.| 6 hrs. | 22 hrs.
wi —_———
er seeds, Au. Canadensis removed I gis: 142.6
Low : intact II 1.6 6. 1.6 1.8
€r seeds, X. echinatum............. removed I | 12.2 :
Upper intact II AE p
re eS glanduliferum.......... removed I ae it.6 é
U : intact II 2.1 ha ea a.
Pper seeds, X. SCnMathiy oe ts ape removed I | 9.4 4
intact II 4.8 Gag]. 2b 28

Pic - % indicates, the lower seeds at 23° take up 1.6 to 1.7
Coats intact . ne gen with the seed coats removed as with the seed
oxygen ‘tia, <. ile the upper seeds take up 2 to 2.4 times as much
ratios are pp Ne seed coats removed as with them intact. The
between ti Pe ly much smaller than would obtain in the soil or
of the eud; ter papers, for the coats of the seeds lying on the walls

lometer, though in a theoretically saturated atmosphere,

274 BOTANICAL GAZETTE. [OCTOBER

became relatively dry. As is found by actual measurement, oxygen
diffuses through the relatively dry seed coats much more rapidly
than through those saturated with water. This is indicated again
by the fact that the soaked upper seeds of X. echinatum germinate
readily at 25-27° when resting on the walls of corked bottles ‘con-
taining air, while in soil or between saturated filter papers a tempera-
ture of 33° is necessary for any considerable germination, The
upper seeds of every species with seed coats intact can be most
easily germinated by allowing the seeds to lie on the walls of corked
bottles of such size that a good oxygen supply is given. In this
condition the relatively dry coats allow the passage of considerably
more oxygen, hence germination comes about at lower temperatures.

The second set of experiments on gaseous exchange is for the
purpose of determining why high temperatures bring about the ger-
mination of the upper seeds with the seed coats intact. It imme-
diately suggests itself that this may be due to one or both of two
things: the amount of oxygen diffusing through the seed coat may
rise with the rising temperature, or the amount of carbon dioxide
evolved may become greater in proportion to the amount of oxygen
consumed as the temperature rises.

It is seen in the 6-hour 50-minute column, as well as in the 12
hour column of Table VI, that the seeds with the coats intact at
19°, whether upper or lower, take up less than half as much oxyge?
as is taken up by the seeds at 33°. This indicates that the diffusion
of oxgyen through the seed coats is much slower at 19° than at cog
This conclusion, however, needs more direct evidence. Especially
is this apparent when it is remembered that 19° is slightly below
the minimum germinative temperature, even with the coats removed,
and that the amount of oxygen consumed, therefore, may not repre-
sent the full amount that can diffuse through the coats at 19°, PFO
vided the consumption on the inside is complete.

The apparatus in jig. 3 was used for determining accurately the
effect of high temperatures on the rate of diffusion of oxygen through
the seed coats. S is a storage bottle for potassium pyrogallate; j, #
flask from which the oxygen is to be absorbed by potassium pyrogallate;
t, a seed coat fastened on the end of a glass tube; w, a vial of wate?
from which a thread reaches the seed coat to keep it wet; ¢, 4 capil

- 1906] CROCKER—DELAVED GERMINATION 275

lary tube sealed at the upper end with wax; c’, a small graduated
tube by which the rate of diffusion of oxygen is to be ascertained; and
a,anair chamber, After s is furnished with 300°° potassium pyro-
gallate the whole apparatus, excepting pinchcock 1 and the portions
of tubes c and c’, is immersed in a water bath regulated to the desired
temperature within .or°, After the apparatus has had sufficient
time to attain the temperature of the bath, pinchcocks 1 and 2 are
loosened; the plugged end of c filed off; and the pryogallate forced
into f. Now c is resealed

and the pinchcocks reclamped; ee

a drop of water is allowed to 1
enter the graduated tube c’; .
and the rate of diffusion of

the oxygen is read by the rate

of the movement of the drop

in tube c’. The same seed :
Coat can be used repeatedly
at temperatures to be com-
pared. Numerous measure-
ments made in this way
Showed the rate of diffusion
1.4 t0 1.6 as fast at 33° as
at 19°,?

The amount of CO;
evolved is considered the best
measure for the amount of
respiration occurring. It is
evident from the measurements
recorded above, that if the ratio CO,:O, remains constant with the
"ise In the available oxygen due to the rise in temperature, the amount
of carbon dioxide evolved will increase from 1 to 1.4-1.6 as the
temperature rises from 19° to 33° with the seed coats intact. If it
happens, however, that the ratio CO,:O, rises in value along with
the rise in the rate of the diffusion of oxygen, then the increase in
respiration with this rise in temperature will be still more marked.

Vics
Ma tat
Hhiy,

—
ries

Q

ii

TELA

Hliiyl

(RUBS
t

Fic. 3.—Apparatus for testing permeability
of seed coats of cocklebur to oxygen. For
description see text.

: When the coat was allowed to dry somewhat the rate of diffusion was also
Sreatly increased.

276 BOTANICAL GAZETTE [OCTOBER

This involves the necessity of making a study of the respiratory
ratios at 19° and at 33°, both with the coats intact and removed.

Table VI shows the effect of high temperatures on the respiratory
ratios when the seed coats are intact. In this experiment equal
weights (2.688") of seeds of X. echinatum were used in each case.
The results are therefore comparable in every way. It is seen that
at 33°, up to the 6-hour 50-minute reading the respiratory ratio for
both upper and lower seeds is 1. After this reading the ratio falls
rapidly, reaching at the 12-hour reading 0.82 in the case of the lower
seeds and 0.87 in the case of the upper ones. It was observed that
soon after the 6-hour 50-minute reading the radicles began breaking
through the seed coats. In a large number of experiments at a3
the respiratory ratio always fell rapidly after the radicles broke the
seed coat. At 19°, with the seed coats intact, the respiratory ratio
is 0.6 in the lower seeds and 0.64 in the upper ones. Many measure-
ments at 33° with seed coats removed showed a respiratory ratio of
o.7—-0.8 in both the upper and lower seeds, while numerous measure
ments at 19° with seed coats removed always gave a respiratory ratio
of about 0.6.

- The facts may be summarily stated thus: the respiratory ratio
with the seed coats removed is about 0.6 at 19° and o.7-0.8 at
33°; with the seed coats intact it is 0.6 at 19° and 1.0 at 33°. From
these results two conclusions are plain: the respiratory ratio rises
considerably (from 0.6 to 0.8) with a rise in temperature from 19°
to 33° under the free oxygen supply secured by the removal of the
seed coats; but it rises much more (from 0.6 to 1.0) with the same

TABLE VI.
X. echinatum—sEED COATS INTACT; 119 UPPER SEEDS; 88 LOWER; 2.68 GM.
Cc. INTERCHANGE OF GASES AFTER

ot ad

Sreps bb oe 4 hrs. so min. 6 hrs. 50 min. to hrs. ais:
| COs
o, | co, | £2] 0, |co,| £2} 0, | co. | 22} 0. | C%|-o,-
O, O: —
Lona ET SR 82

WCE (es a sie a es 33 3313-3} 1. +4-914-9 11 7-9 6.5 .83 9.9 | 8-3 ‘
Upper’. 2.44.; So 17.9148! fea las le &. | §-3] .88 7-15-9 ws
Lower 2205 19 1.8i1.1 | .61 4.0) 2-4 6
Upper. esc22k- 19 r.5 1-04} .63 $5421
gare ones

1906] CROCKER—DELAYVED GERMINATION 277

rise in temperature when the oxygen supply is diminished by the
presence of the seed coats.

This rise in the respiratory ratios with the rise in temperature
is measured for the entire seed (more than 95 per cent. of which is
storage material) and not for the actively growing radicle. It is
probable that for the radicle the respiratory ratio rises far above
1. This becomes more evident when it is remembered that at 33°
the radicle grows first, as is normal; but that at 22°, in increased
oxygen pressures, though it be five atmospheres, the growth of the
cotyledons first takes place. Here, too, it should be recalled that
the seed coat is much thicker and more dense over the radicle than
over the cotyledons,

From the data of this section two effects of a rise in temperature
are evident. It increases the rate of diffusion of oxygen through
the seed coats; and it increases the respiratory ratio somewhat
with the seed coats removed and markedly with the seed coats intact.
If CO, be taken as the criterion, it is possible from the data above
to calculate quantitatively the increase in respiration with a rise in
temperature from 19° to 33°, when the seed coats are intact. The
crease in the rate of diffusion of oxygen (if there were no increase
in the ratio CO,:O,) equals an increase in respiration from 1 to
1.5 (the average of 1.4-1.6). But the increase in the respiratory
ratio is from 0.6 at 19° to t.0 at 33°. This then increases the res-
Piration from 6 units to 10 units. When the two facts that indicate
an increase in respiration are considered together, it is evident that
a rise in temperature from 19° to 33° with the coats intact causes a
tise in the amount of respiration from 0.6 to 1.5; or from 1 unit to
2.5 units, ‘

It is evident from Table V that the seed coats of the lower seeds,
as well as those of the upper, greatly restrict the amount of oxgyen
used by the seeds, and that this restriction, though considerable, is
hot markedly greater in the upper seeds than in the lower ones.

X. echinatum this rather slight difference in the rate of diffusion
of oxygen through the seed coats of the upper and lower seeds is
yet sufficient to give the upper seeds a minimum germinative tem-
perature of 32° with seed. coats intact, and the lowers 22°; while
both seeds with the seed coats removed have a minimum germinative

278 BOTANICAL GAZETTE [OCTOBER

temperature of 19°. Since the difference of the two seed coats in
the matter of oxygen diffusion is rather slight, it is not remarkable
that the structural difference is not radical. This slight difference,
however, is sufficient to raise the minimum germinative temperature
and secure the delay of the upper seed.

Growth of upper seeds—It is now obvious how the delay of the
upper seeds is secured. But why do they grow at all in nature?
This comes about by a partial disintegration of the seed coats, which
is clearly shown by a change in appearance from shiny brown to a
dull black or in some cases to colorless, and results in the admission
of more oxygen. The length of the delay depends upon the ability
of the seed coat protected by the surrounding bur to resist the factors
of disintegration in the soil. The portion of the bur covering the
lower seed decays within a few months after burial, while the portion
covering the upper seed is always far more persistent. A variation
in the persistence of the portion of the bur covering the upper ‘seed,
as well as the variation in the ability of the seed coat to resist the
factors of disintegration independent of the bur, gives considerable
variation in the length of delay of the upper seed. These facts
show why only a few of the upper seeds grow the first year after
ripening, the vast majority the second year, and a few not until the
third and fourth year.

Table VII shows the effect of a period in the ground upon the
seed coats and upon the vitality of the embryos of the upper seeds of
X,._canadense. Burs produced in 1904 were gathered in November
of that year and stored in the laboratory until March 1905. At this
time half these burs were buried and the other half kept in the labora-
tory. In November 1905 the upper seeds of 1904 burs stored in the
laboratory, of 1904 burs buried eight months, and of 1905 burs
gathered from the same patch, were removed and put to germinate.
At 28-33°, with coats intact as Table VII shows, upper seeds of 1904
buried eight months gave 96 per cent, germination, upper seeds of
1904 stored in the laboratory gave o per cent., and upper seeds of
1905 gave 3 per cent. As shown in the same table, similar seeds
with the coats removed in a germinator at 18-22° (near the minimum
germinative temperature with the seed coats broken) gave in UpPtT

seeds of 1905 prompt germination, in upper seeds of 1904 stored

1906| CROCKER—DELAYVED GERMINATION 279

TABLE VU.
X. canadense; UPPER SEEDS.
PER CENT. GERMINATED AFTER
SEEDS Coats | TEMP |

| 3 days 6 days 33 days
Aires pint Pathered oc. nie iv cig os: on | 28-33 ° > 3
1904 stored in laboratory 1 yr....... on | 28-33 9° S es
1904 in lab. 4 mos., buried 8 mos.... on | 28-33 44 96
POOR TUSL patncred oi oe ae off 18-22 48 100 100
1904 stored in lab. 1 yr.:.......... off | 18-22 20 42 100
1904 in lab. 4 mos., buried 8 mos. | off | 18-22 Oo] 4 94

in the laboratory less prompt germination, in upper seeds of 1904
buried eight months much less prompt germination. From this
table two things are evident. A period in the ground causes a partial
disintegration of the seed coats which lowers the germinative mini-
mum temperature with the seed coats intact. This accounts for the
results in Table VII with the temperature at 28-33° and the coats
intact. The vitality (if we mean by vitality the readiness with which
seeds will germinate at a given temperature) of the embryos falls
somewhat with a year of dry storage and markedly with eight months
in the ground.
2. AXYRIS AMARANTHOIDES.

L. R. Watpron of the North Dakota Agricultural College informed
me that Axyris amaranthoides bears two kinds of seeds. One grows
soon after being subjected to germinative conditions and the other
fails to grow under similar conditions. The former, which is flattened
and winged (fig. 4, a) he designated as a; the latter, which is almost
spherical (fig. 4, b), as 6, From material
kindly furnished by him I have found that
the distal portions of the branches bear
entirely form a, and the proximal portions
entirely form 6; while the intermediate zone
bears both forms even within the same seed
oh fos! es is either one form or the 5, —Dim eae

g no intergrading. Seeds seeds of Axyris amaran-
of form a and 6 are about equal in number. “24s. =
It is found that form 0 fails to grow because the seed coat is only
very slowly permeable to water, Form a soaked in water at 2 tek

280 BOTANICAL GAZETTE [OCTOBER

absorbed after 24 hours 39 per cent. of dry weight, after 48 hours 70
per cent. Form 6 absorbed after 24 hours 4 per cent., after 48
hours 5 per cent., after 120 hours 6.5 per cent., and after 174
hours 9.5 per cent. After 174 hours soaking, 2 per cent. of form
b had swollen up and germinated. At 23° with seed coats broken,
as shown in Table IX, form b germinates much more readily than
form a with seed coats intact, and somewhat more readily than form
a with seed coats broken. It is evident from these tests that the
embryo of form } is more vigorous than the embryos of form 4.

It should be pointed out that the embryo of form 6 has an ideal
storage condition, The water-excluding seed coat keeps it dry as
it lies buried in the ground with the temperature relatively low.
With the partial disintegration of the coat comes the admission of
water and the growth of the embryo. The length of the delay in
germination thus secured will vary greatly with water and tempera-
ture conditions, and with the different individuals of form 6. It is
probable that it will amount to many years in some cases.

In Axyris, as in the cocklebur, the same plant bears two sorts of
seeds, One sort grows rapidly in nature and the other only after
a considerable delay. Unlike the cocklebur, the seeds are not paired,
and the delay is secured by the seed coat shutting out water rather
than oxygen.

3. ABUTILON AVICENNAE AND CHENOPODIUM ALBUM.

Agriculturists claim that the seeds of Abutilon Avicennae lie in
meadows and pastures for twenty years without growing, but upon
breaking the soil grow in great abundance. When these seeds are
soaked in water for forty-eight hours about 13 per cent. swell up,
while the embryos of 87 per cent. remain extremely dry and can be
pulverized. After weeks of soaking only a small per cent. additional
will swell, a few at a time. For the relative per cent. of germination
of these seeds with seed coats intact and seed coats broken see Table
IX.

In Ci heno podium album, mentioned in the NoBBE-HANLEIN table,
about 16 per cent. of a crop of seeds swell up after twenty-four hours
soaking. By continual soaking the remaining seeds gradually swell
a few at a time, but much more readily than is the case with Abutilon.

1906] CROCKER—DELAYVED GERMINATION 281

Contrary to NopBe AND HANLErIN’s conclusion, the distributed germi-
nation shown by this species is secured by the slowness with which
water penetrates the seed coats.

While in Axyris and Xanthium delayed or distributed germina-
tion is secured by peculiar seed coat characters of one form of the
dimorphic seeds, in Abutilon Avicennae and Chenopodium album
the distributed germination is secured by a variation in the seed
coat characters of similar seeds.

4. IRIs.

Dr. C. J. CHAMBERLAIN informed ‘me that he had never succeeded
in germinating seeds of various species of Iris, although he had often
attempted it in order to have root tips for cytological purposes. The
bulk of the seed consists of the horny endosperm with food stored
on the walls as hemicellulose. On one side of the endosperm is a
cylindrical cavity in which the embryo is borne. The cavity is
covered by a cap, thus entirely closing in the embryo, When the
seed is dry, the embryo only partially fills the cavity, but after twenty-
four hours soaking it completely fills it. In this condition, however,
the seeds will lie for weeks without germinating. If now the caps
are removed and the seeds still kept in the water, the embryo pro-
trudes 3~-7™™ within an hour. Seeds with caps removed germinate
very readily, while those with caps intact do not germinate at all.
For the effect of removing the cap in Iris sibirica and I, Pseudacorus,
pie Table IX. Increased oxygen pressure and high temperatures
with the caps intact did not cause germination. With the caps
‘moved, the most successful germination was secured by using
Sterilized sand as a germinator at 28-33°.

The amount of moisture absorbed by the embryo within the
miting wall of the endosperm is not sufficient to permit growth to
egin. By taking away this limit to water absorption by removal
of the cap or a portion of the endosperm in the region of the embryo, *
absorption is resumed and growth soon begins. Judging from a
umber of observations, it appears that in nature long soaking and
“¢companying disintegration lead to the loosening of the cap, or
more frequently to the decay of the endosperm at one side of the
embryo,

li

282 BOTANICAL GAZETTE [OCTOBER

TABLE VIII.
: | PER CENT. GERMINATED AFTER
SPECIES ages 4 | Coats
2 days | 3 days | 5 days | 9 days | 38 days
Plantago major... 3.2... 28-33 | entire 20 28 44 54 60
Se broken 50 81 92 96 96
18-22 | entire ° ° ° ° °
broken fe) ° ° ° °
Plantaso Rugelli.: 2208 28-33 | entire 2 2 9 15 38
re broken gI 98 08 98 98
18-22 | entire ° fe) fe) fe) °
broken ° ° oO 72 12
Uhlaspi arvense 2.02. 6.3... 28-33 | entire 32 38 AI 41 41
4 roken 94 100 100 100 | I00
18-22 | entire fe) fe) ° fe)
oken 48 75 86 93 96

I was obliged to abandon work on these seeds, for on account of
handling them I had repeated and severe attacks of dermatitis from
contact with the syrupy covering of the endosperm. The symptoms
were identical with those of Rhus poisoning.

5. THE Noppe-HANLEIN TABLE.

Beside Chenopodium album, I have studied the following seeds
mentioned in the Noppe-HANLEIN table: Aquilegia vulgaris, Cap-
sella Bursa- pastoris, Lysimachia vulgaris, Plantago major, P. Rugelii,
and Thlaspi arvense. It was found, in agreement with NoBBE and
HANLEW, that all these seeds absorb water readily.

In Aquilegia vulgaris NopsE and HANLEIN obtained a germina-
tion of only 0.75 per cent. after sixteen days, and no more during
the remaining three years. In all tests at 23° I found over 5° pe
cent. germinating within thirty days. None generally germinated
short of sixteen days because of the rudimentary state of the embryo.
Breaking the seed coats cut down the percentage of germination by
allowing infection by fungi which the slow growing embryos were
unable to resist.

Table VIII shows the germination of seeds of Plantago major,
P._Rugelii, and Thlaspi arvense at 18-22° and 28-33° with seed
intact and seed coats broken. It is seen that with seed coats broken
and with favorable temperatures over 95 per cent. germinate 17

every case. These results should be compared with Table I, in which

Tg06] CROCKER—DELAYED GERMINATION 283

Nosse and HANLEIN show the germination of only 0.25 per cent.
of P, major, 10.75 per cent. of P. media, and 21.75 per cent. of
Thlaspi arvense after 1,173 days. In the last species the germination
is late in that period.

From Table VIII several important facts are evident. The tem-
perature of 18-22° is below the minimum germinative temperature
of seeds of P. major with seed coats intact or broken, and below that
of P. Rugelii and Thlaspi arvense with seed coats intact. It is very
near the germination minimum of P. Rugelii with seed coats broken
and well above that of Thlaspi arvense in similar condition. A very
marked increase in germination is secured by rupturing the coats
even when the most favorable temperatures are used, High tem-
peratures, then, will overcome only in part the seed coat effects.
High temperatures are more efficient in overcoming the seed coat
effects in P. major than in P. Rugelii.

In Table IX a similar effect of rupturing the seed coat is shown
for Capsella Bursa- pastoris, Lysimachia vulgaris, and Euphorbia
Cyparissias, It should be mentioned that the region and extent

TABLE: IX.
TEMP. 18—-22° EXCEPT FOR IRIS, WHICH WAS 28-33°.
PER CENT. GERMINATED AFTER
SPECIES Coats
1 day | 3 days| 6 days | 14 days | 20 days | 30 days

Abutilon Aviceniae. 33. G3], entire ° 13 13 13 13 13
broken 48 98 98 98 98 98
mvend ths 66 ee entire © ° 8 8 8 8
broken ° 4 92 96 96 96
Capsella Bursa-pastoris...... entire fe) 8 14 15 15 AD
Ch ; broken fo) 80 oo 100 100 100
e enopodium album........ .| entire ° Io 16 16 16 16
: broken ° 80 100 100 100 100
Euphorbia Cyparissias ....... entire ° ° 2 20 20 20
* : broken fa) 20 84 84 84 84
Lysimachia Wilgatie. (20 entire ° ° ° ° ° °
: broken ° 44 64 64 64
Axyris amaranthoides A...... entire ° 76 92 94 96 96
: broken 14 100 100 100 100 100
A. amaranthoides B......__. entire ° ° ° ° ° °
si ae roken Be OO 4 TOG £00 < |) 100%") 00
Tris ec cap on ° ° ° fs) ° )
- cap off ° 6 18 98 8
Tris Pseudacorus.,......-... a on ° ° & ° a
cap off ° 14 4. 32 et 4 OF. 1-97

Ce retest aus

284 BOTANICAL GAZETTE [OCTOBER

of the rupture makes no difference so long as the embryo is not
injured.

Nosse and HANLEIN make no mention of the temperature main-
tained in the course of their experiments and seem unconscious of
the fact that the temperature plays an important part. Judging from
the results in Table VIII as compared with their results in Table I,
they must have run their germinators at relatively low temperatures.
These investigators, as well as WINKLER, were likewise entirely
unaware of the effect of the seed coats upon germination.

6. AVENA FATUA.,

Avena jatua has some germinative characters which are inter-
esting and which show that the seed coat characters just described
for other seeds appear in the grasses. Table IX shows that at 18-22”,
8 per cent. grow with seed coats entire and 96 per cent. with coats
broken. At 33°, 50-60 per cent. grow with coats entire and 97 per
cent. with the coats broken. This seed coat character probably dis-
tributes the germination of a given crop over a period of years. It
probably accounts for the claim of farmers that these grains will lie in
pastures and meadows for twelve to fifteen years and then grow
abundantly when land is plowed. WaALpRoN (12) believes this idea
is wrong, but it is easy to see how his vitality tests might be entirely
misleading, for the seed coat character just described was not taken
- into account.

7. HAWTHORNS.

I found, as. is popularly believed, that no hawthorn seeds will
grow immediately after ripening. The seeds of various species were
tested by removal of seed coats and subjection to high temperatures
and high oxygen pressures; but none of these conditions sufficed to
cause germination. Seeds that lay in the soil for a year or more
germinated to some extent; while seeds stored in the dry for a similar
period did not germinate at all, although the tests were made with
naked embryos as well as with seeds bearing the coats. It is evi-
dent, therefore, that the change that must precede germination is
in the embryo itself rather than in the seed coat; but it is also more OF
less a matter of disintegration, as is true in seeds whose germination
is delayed by seed coats.

1906] CROCKER—DELAYED GERMINATION 285

IV. General considerations.

Two statements of ARTHUR concerning the cocklebur need special
consideration. He says: ‘Seeds in the bur retain their germinative
power, when kept in a dry room, for two years or more; but seeds
removed from the bur dry out within a few days and will no longer
grow. Seeds removed from the bur and placed in a germinator retain
their bright polished appearance as long as they are alive; when dead
they turn dull and lusterless.” I find that the seeds retain their
vitality fully as well when removed from the bur and allowed to dry
as when in the bur. In fact, a dry cool place is the best for storage
of these seeds whether in or out of the bur, as is true for most seeds.
The seeds removed from the bur and kept in a dry place retain their
vitality much more than five years. I found the condition of the
seed coat no indicator of the vitality of the embryo. The coat through
disintegration loses its luster and turns black or sometimes colorless,
which means that more oxygen is admitted and that the minimum
germinative temperature of the seed has fallen. It is not surprising
that ARTHUR drew these conclusions, for his work gave him no idea
of the germinative conditions of the upper seeds or of the significance
of the seed coat,

As Duvet (3@) states, seeds retain their vitality longest in condi-
tions that permit of least respiration. KoLKwiTz (5) has shown that
respiration is extremely slight in dry seeds at low temperatures.
The embryos of seeds whose germination is delayed by coats that
exclude oxygen, such as Abutilon, Axyris, and Chenopodium, are
kept very dry by the coats. As they lie in the ground they are like-
wise relatively cool. In nature, in short, they have the most favor-
able storage conditions up to the time when the coats, through partial
decay or long exposure to water, admit moisture and germination
begins. It is not wonderful that such seeds lie in the ground twenty
'o twenty-five years and yet retain their vitality. While the reduction
in the oxygen admitted to the upper seed of the cocklebur cuts down
the respiration considerably, it does it to no such extent as does the
exclusion of water. The coats that exclude water are undoubtedly
much better ada pted to securing a long delay than are the coats that
merely exclude oxygen. In nature the longer delays are certainly
secured by the former method.

286 BOTANICAL GAZETTE [ocroBER

PFEFFER (9) says: “The conditions which lead to certain seeds
resting under the soil for as long as fifty years and germinating when
dug up have not as yet been determined.’ This, as well as the
sudden appearance of weeds in forests after fires and in meadows
of many years standing immediately upon plowing, is probably
explained by a few simple facts. Weed seeds are produced in great
abundance. Because of variation in seed coat characters or in some
cases of embryo characters, a given crop distributes its germination
over a period of years. Seeds deep in the soil germinate less readily
because of lack of oxygen or water, and those that do grow exhaust
the stored food before reaching the surface. Bringing such seeds
to the surface greatly increases their germination and removes the
danger of exhaustion of the stored food. The plants of meadows and
forests keep the water supply reduced and thereby cut down the
chances for the germination and later growth of the weed seeds present.
With the destruction of the plants of the forest or meadow comes 4
great increase in the germination of the weed seeds and a removal of
the opposition to their future growth. These phenomena, then, will
probably all be explained by a study of the germinative characters
of the seeds such as is described in the experimental portion of this
paper, along with certain other well established facts on germination.

It is undoubtedly true that many of the tests that have been made
for the vitality of weed seeds are untrustworthy, because the signifi-
cance of the seed coats has been overlooked. This is clearly shown
by the results of Duvet (3b) and WALDRON (12), who have carried
on extensive experiments to determine the length of time weed seeds
must be buried in order to lose their vitality, In column I of
Table X is shown the percentage germination determined by
me with seed coats broken and with favorable temperatures. In
column II appear Duvet’s results, in which he uses what he terms
the “most favorable temperatures,” but overlooks of course the seed
coat effects, The figures quoted from Duvet are from the column
“original samples,” which means fresh seeds, as were the seeds for
determining the percentages of column I.

The effect of rupturing the seed coats, as is shown in this table,
is very evident, although Duvet has in part overcome the seed coat
effects by high temperatures. The average percentage of germina-

1906] CROCKER—DELAYVED GERMINATION 287

TABLE Xs

| I | II

|
1. Ax yrs AMarantnoides <<... 55 2-16 ayes es, | 100 | °
2. Xanthium pennsylvanicum.............-.... gos 5) 5°
3 alaspi CONSE. AAS eS eee | kere) 57
4. Blantago Rupelli. oo oc. ee 96 4
5. Avena fatuad 2. oo a ene a 96 | 75
6. Piantago major.<'. > +4 sein < Deco ee ek 905-4) 24
%, Chenopodium album: ¢. 0 +.<..., 5. 6s ee | 100 | 67

tion for the seven species tested is 98 per cent. with seed coats rup-
tured, 40 per cent. with seed coats intact. It may be urged that the
seeds used by Duvet are of low vitality. This, however, does not
seem at all probable, for I obtained only slightly higher percentages,
as shown in Tables VIII and IX, with the coats intact and with
favorable temperatures, than those reported by Duvet. These
slightly higher percentages can be accounted for by the fact that the
temperature used by me was 28-33°, while the temperature used by
DUVEL was 20-30°, Two species of seeds mentioned in this table
need special consideration. In Axyris amaranthoides, DUVEL deter-
mined the vitality as o per cent. This is exactly what would. be
expected if form 6 alone (as shown in Table IX) were used, and if
the effect of the seed coat were overlooked. In Xanthium pennsyl-
vanicum he finds so per cent. germinating. This, too, is what would
be expected if the upper and lower seeds of the cocklebur were put
in a germinator at 20-30°. The lower seeds would germinate in
this condition and the others fail to do so. It seems probable, then,
that in Xanthium and Axyris Duvet overlooked the dimorphic
character of the seeds, as well as the effect of the coats on germina-
ion. Vitality tests of this kind, that neglect the effect of the seed
“oats, are tests of the condition of the seed coats rather than tests
of the real vitality of the embryos themselves. It is evident that if
these errors appear in the original tests for vitality they will likewise
‘ppear in the tests made after different periods of burial. If vitality
tests, looking to the extermination of weeds, are to be of real value,
the ©xact germinative character of each species must first be deter-
mined, and all vitality tests must then be mide on the basis of these
Serminative characters. :

288 BOTANICAL GAZETTE [ocTOBER

It is obvious that the seeds which fail to grow in the ordinary
grain tests often do so because of seed coat characters rather than
because of lack of vitality of the embryos. This, however, does not
in any wise invalidate the ordinary methods of testing grains to be
used for seeding, since seeds that are delayed a month or more in
germination are of no value in producing the crop. On the other
hand, when it comes to testing weed seeds, looking toward extermi-
nation, it is highly important that these seed coat characters be taken
into consideration.

I am impressed by the high vitality of weed seeds. This is
especially true of the more noxious weeds and those in which the
seed coat secures a long delay. The high vitality is not shown alone
by a quick response to germinative conditions. The percentage of
germination in noxious weeds, provided real germinative conditions
are given (the seed coat hindrance removed), is very close to 100;
and a marked growth of the embryo generally takes place within
two days after being subjected to germinative conditions. After
recognizing this fact, one is led to suspect that many other cases
of low vitality in weed seeds mentioned by Duvet and others (not
examined in this paper) must be due to seed coat characters rather
than to lack of vitality in the embryos.

While this paper indicates, exactly contrary to the conclusions
commonly held, that delayed germination is in most cases secured by
seed coat characters, it yet recognizes that in the hawthorns delay
is secured by embryo characters. It is probable that a number of
other seeds will be found to belong to the same category as the haw-
thorn. It is of great interest to know just the changes which take place —
in the seeds of the hawthorns and finally lead to germination through
long exposure to germinative conditions. This subject is now under
investigation. It must be urged that, until these changes are under-
stood, any attempt to determine the vitality of such seeds is futile.

The methods by which seed characters that secure delayed germ!
nation have come about naturally deserves consideration. It may
be adaptation coming through natural selection, but an attempt to
prove this would end in failure. This delay in many cases, however,
is of undoubted advantage to the species. ARTHUR urges that 10
the cocklebur the two seeds are borne in an indehiscent structure,

1906] CROCKER—DELAVED GERMINATION 289

the bur, and that it is impossible to have the two seeds distributed
in space, so a distribution in time is substituted. Why such an inde-
hiscent involucral structure should be developed instead of such a
bur as appears in the burdock needs answer. With the indehiscent
bur already in existence the advantage is plain. It is clear that such
germinative characters as appear in the seeds of Axyris amaran-
thoides, Abutilon Avicennae, etc., insure that the soil will always be
supplied with these seeds in process of germination. The destruc-
tion of existing vegetation, by fire or otherwise, is followed by a
quick appearance of these weeds. In species where none of a given
crop of seeds grow until a year or more after falling, it would seem
that the adaptive characters, if they be such at all, had overstepped
the line of greatest advantage.

V. Summary.

1. Delayed germination is reported in the seeds of many plants
and, exactly Opposite to the common view, its cause generally lies
in the seed coats rather than in the embryos; but in the hawthorns,
as perhaps in some other seeds, it is due to embryo characters.

2. In the upper seed of the cocklebur the delay is secured by the
seed coat excluding oxygen, while in Axyris amaranthoides, Abutilon
Avicennae, and many other seeds, it is secured by the coats excluding
water.

3. In Iris seeds the failure to germinate is due to the endosperm
and cap stopping water absorption before the quantity necessary for
germination is obtained by the embryo. 3

4. In Plantago major, P. Rugelii, Thlaspi arvense, Avena jatua,
and others, the real method by which the coats secure the delay is
hot yet determined, but there is no doubt that the delay is due to
the coats,

5. Seed coats which exclude water are much better adapted to
securing delays than are seed coats which exclude oxygen, because
of the much greater reduction of respiration in the first case.

6. In nature growth of the delayed seeds comes about through
the disintegration of the seed coat structures by a longer or shorter
exposure to germinative conditions, and the length of the delay
depends upon the persistence of the structure securing it.

290 BOTANICAL GAZETTE [OCTOBER

7. In the cocklebur the bur aids in preserving the seed coat of
the upper seed by being most persistent over it.

8. Even in the hawthorns, where the delay is secured by embryo
characters, the germination finally comes about in the course of
long exposure to germinative conditions and not in dry storage.

g. In the cocklebur the seed coats of both the upper and lower
seeds cut down the oxygen supply, but the first the more markedly.
This gives the upper seed a much higher minimum germinative
temperature and the lower seed a somewhat higher one. Hence we
have in the cocklebur seeds two minimum germinative temperatures;
one with the seed coats intact and a much lower one with the coats
removed. In the‘upper seeds these differ by fifteen or more degrees;
in the lower seeds by three to five degrees.

to. High temperatures bring about the germination of the upper
seeds of the cocklebur with coats intact by increasing the rate of
diffusion of oxygen through the seed coat and by raising the respira-
tory ratio.

11. The minimum germinative temperatures of the seeds of the
cocklebur, Plantago major, P. Rugelii, Thlaspi arvense, and various
other seeds, with the seed coats intact, is far above the highest mini-
mum germinative temperature repuried: while in the cocklebur and
Plantago major with coats removed this critical temperature is
considerably above the highest reported.

I am indebted to Professor Cuas. F. Horres, of the University of
Illinois, for suggesting the problem in reference to the cocklebur, and
to Professors Joun M. Coutrer and C. R. Barnes for kind suggestions
and assistance during the progress of the work.

ray LITERATURE CITED.

1. ARTHUR, me C., Delayed germination in the cocklebur and other paired
roc. Soc. Prom. Agric. Science 16:70-79. 1895.

2. Derurs, itp , Keimungsprocess der Samen 427. 1880

3a. Duvet, J. W. T., Vitality and ere of exile. U. S. Dept. Agric.
Bur. Plant Ind., Bull. 58.

eae. , Vitality of buried an ties: Bull. 83. 1905.

4. Kienrrz, M., Ueber Ausfiihrung von Keimproben. Bot. Centralbl. 1752753
1880.

1906] CROCKER—DELAVED GERMINATION 291

5. Korxwitz, R., Ueber die Athmung ruhenden Samen. Ber. Deutsch. Bot.
Gesells. 19:285~-287. igor.

6. Kuntze, Ricuarp E., Germination and vitality of seeds. Published by the
Torrey Bot. Club. | 1901.

7. Masterman, E. E., Sprouting of cocklebur seeds. Ohio Nat. 1:69-7o.

Igot.
8a. Nosse, F., and HAntern, H., Ueber dei Resistenz von Samen gegen die
aiisseren Factoren der Keimong. Landw. Versuchs-Stat. 20:63-96. 1877.
8b. ———., Ueber die Keimkraft von Unkrautsamen. Landw. Versuchs-Stat.
:465-470. 1880. *
9. Prerrer, W., Physiology of plants (Eng. ed.) 2:208. rg00.
0. Stone, G. E., Influence of chemical solutions upon the germination of seeds.
Rept. Mass. Agr. Exp. Sta. 13: 74-83. rgor.
11. THompson, A., Zum Verhalten alter Samen gegen Fermentlésung. Garten-
flora 45:344. 1896.
12. WaLpRon, L. R., Buried weed seeds. N. Dak. Agr. College Bull. 62. 1904.
13. WaucH, Frank A., The enzymic ferments in plant physiology. Science
N. S. 6:950-952. 1897
14. Wiesner, J., Ueber die Ruheperiode und von einige Keimungsbedingungen
der Samen von Viscum album. Ber. Deutsch Bot. Gesells. 15: 503-515.
1897
- Wrvkter, A., Bermerkungen iiber die Keimpflanzen und die Keimfahigkeit
des Samen von Tithymalus Cyparissias. Ber. Deutsch. Bot. Gesells.
1: 452-455. 1883.

al

Lead
mn

UNDESCRIBED PLANTS FROM GUATEMALA AND OTHER
CENTRAL AMERICAN REPUBLICS. XXVIII."
JouHN DONNELL SMITH.

Saurauja Maxoni Donn. Sm.—Glaberrima. Folia nitida obovato-
oblonga in apicem angulo obtuso in basin angulo acuto desinentia
calloso-denticulata, nervis lateralibus remotissimis arcuatis. Pani-
culae subterminales longe pedunculatae folia subaequantes. Sepala
paene glabra.

Frutex 3-4-metralis, ramulis laevibus. Folia crassa 14-20°™ longa 6-8
lata, margine vix ac ne vix undulato, nervis lateralibus haud parallelis 1. ge
inter se distantibus, petiolis validis 2-3°™ longis. Pedunculi ro-17°™ longi et
panicularum axes complanati striati nitidi, axibus primariis alternis 1.5~?- ase
longis, pedicellis 4-5™™ longis, bracteis lincaribus 4™™ longis et bracteolis cilio-
latis, floribus 2.5°™-diametralibus. Sepala ovalia 7-8™™ longa juxta marginem
basinque intus pubescentia. Petala discreta oblongo-ovata bilobulata. Filamenta
basi cinereo-barbata antheris aequilonga, loculis dimidio discretis. Ovarium
glabrum 5- vel rarius 3-loculare, stylis discretis 4.5™™ longis.

Secanquirh, Depart. Alta Verapaz, Guatemala, alt. 550”, Jan. 1995; Maxon
et Hay (n, 3221).

Saurauja ovalifolia Donn. Sm.—Strigillosa. Folia ovalia bis
longiora quam latiora apice obtusa basi rotundata supra scabriuscula
subtus nervatione pubescentia mucronulis denticulata. Paniculae
pauciflorae. Sepala strigillosa et pubescentia. Bacca magna villosa.

Frutex orgyalis. Ramuli petioli pedunculi panicularum axes strigillis fer-
rugineis pilo albo apiculatis operti. Folia 20-23°™ longa, nervis lateralibus
utrinsecus 20-22, venis utrinque manifestis, petiolis circiter 2.5°" longis. Pedun-
culi ex quaque axilla nascentes 7-10°™ longi, paniculis 4-6°™ longis, axibus
plerumque geminatis 1-2°™ longis, pedicellis 5-1o™™ longis, bracteolis linearibus
7-1o™™ longis. Sepala acuminato-ovata 7™™ longa. Bacca sordide —_
9™™-diametralis 5-locularis polysperma, stylis discretis 5™™ longis, seminibus
vbovatis scrobiculatis—Petala et stamina in exemplis 2. gamers deficiunt.
Rio Navarro, Prov. Cartago, Costa Rica, alt. rroo™, Mart. 1894, J: Donnell
Smith, n. 4746 ex Pl. Guat. etc. quas ed. Donn. Sm.

Saurauja subalpina Donn. Sm.—Furfuraceo-strigillosa. Folia
longe petiolata oblanceolata utrinque acuta mucronulis incurvis

* Continued from Bor. GazeTTE 40:11. 1905. :
Botanical Gazette, vol. 42] : aid

1906] SMITH—PLANTS FROM CENTRAL AMERICA 293

denticulata supra tuberculis rubiginosis setuligeris scabra subtus
nervis approximatis et venis rufo-strigillosa et parce pubescentia.
Pedunculi petiolis parum longiores, floribus inter majores. Sepala
furfuracea tuberculato-setulosa, Ovarium glabrum.

Ramuli petioli pedunculi panicularum axes simul cano-furfuracei et longe
rufo-strigillosi. Folia 20-22°™ longa 6-7°™ lata, nervis 5-8™™ jnter se distantibus,
venis minutissime reticulatis subtus tantum manifestis, petiolis 3-4°™ longis.
Pedunculi axillares 4-5 longi, paniculis circiter 6°™ longis floribundis, axibus
alternis, pedicellis 4-8™™ longis, bracteolis linearibus 3-5™™ longis, floribus
2.5°™-diametralibus. Sepala ovata 6-8™™ longa, setulis validis brevibus puberu-
lis. Petala discreta obovato-oblonga. Filamenta pilis articulatis barbata antheris
infra medium affixis paulo longiora, loculis triente discretis. Ovarium 4-5-
loculare stylis discretis 6™™ longis bis superatum,

Volcan de Agua, Depart. Zacatepéquez, Guatemala, alt. 3300™, Apr. 1890,
J. Donnell Smith, n. 2171 ex Pl. Guat. &c. quas ed. Donn. Sm.

PRuNUS CAPOLLIN Zucc., var. prophyllosa Donn. Sm.—Ramuli
racemiferi peruliferi subaphylli pedunculum lateralem mentientes,
perulis ovalibus 12-18™™ longis apice retusis sicut stipulae lineari-
lanceolatae glandulo-denticulatae 16-19™™ longae atque bracteolae
oblongae 7-10™™ longae purpurascentibus pubescentibus. Flores
nondum satis evoluti solum cogniti.

San Rafael, Depart. Zacatepéquez, Guatemala, Mart. 1905, Maxon et Hay
{n. 3666).

Tibouchina paludicola Donn. Sm. (§ DIoTANTHERA Triana,)—
Patentim glandulari-setulosa, Folia ovata vel lanceolato-ovata acu-
minata basi rotunda vel leviter cordata supra sparse, subtus nervis
venisque, setulifera denticulata 7-g-nervia. Flores axillares singuli
vel cymulis trifloris terminales, Stamina glaberrima cum stamino-
diis alternantia, connectivo longe producto, Ovarium nudum,

9 apicali 2™™ longo, connectivo usque ad 3.5™™ producto. Staminodia
filiformia 4™" Jonga ananthera. Ovarium ovoideum 3™™ altum vertice nec his-
pidum nec Setosum, stylo 2°™ longo. Fructus globoso-ovalis 3"° longus.—
Species staminodiis et ovario anomala.

294 BOTANICAL GAZETTE [OCTOBER

In paludibus secus Rio Cafias Gordas, Comarca de Puntarenas, Costa Rica,
alt. rr0o™, Mart. 1897, Pittier (nn. 11055, 11056).—In filictis paludosis secus
Rio El General, Diquis, Comarca de Puntarenas, C. R., alt. 7oo™, Febr. 1898,
Pittier (n. 12150).

Monolena Guatemalensis Donn. Sm.—Rhizoma glabrum elonga-
tum. Folia longe petiolata cordato-ovata acuminata integra 7-9-
plinervia, lobis basalibus imbricatis. Scapus basi squamis fultus
ceterum nudus petiolo longior pluriflorus. Styli basis ovoidea quam
capsula major.

Rhizoma 8-17™™ crassum 7°™ et ultra longum fibrillosum squamis triangu-
laribus 1™™ longis ferrugineis conspersum, squamis scapum fulcientibus imbri-
catis triangularibus vel lanceolatis 3-7™™ longis. Folia ob folium alterum cadu-
cum quasi alterna. 1o-16°™ longa 6-10™ lata utrinyue punctulata et lineolata mu-
crunculis hinc inde ciliata, petiolis 6-19 longis. Scapus 14-20°™ longus sicut
petiolus in sicco rubescens, cyma 4~8-flora, pedicellis 2-3™™ longis, bracteis
— Calycis florentis tubus carnosulus - altus, lubi mempbranacei ovati

jeliude pide eros exlobata. Petala 23™™ longa rosea. Capsula calyce
3-plo superata, valvis acute triangularibus 3™™ longis sicut styli basis 47™ longa
cartilagineis pallidis, seminibus vix 1™™ longis.

Guatemala, Depart. Alta Verapaz: in fundo Sepacuité dicto, Mart. 1902,
Cook et Griggs (n. 106), Apr. 1y02, Cook et Griggs (n. 575); in declivibus humidis
inter Senahti at Actal4, Jan. 1905, Maxon et Hay (n. 3331); secus viam inter
Sepacuité et Secanquir, alt. 1200", Maj. 1905, H. Pittier (n. 314).

Conostegia dolichostylis Donn. Sm.—Tota praeter foliorum pagi-
nam superiorem plus minus dense stellato- et ferrugineo-pubescens.
Folia lanceolata superne subsensim tenuiterque, deorsum brevius,
acuminata obsolete sinuato-denticulata 5-plinervia. Flores paucl
graciliter pedicellati 5-meri inter maximos. Stylus stamina longe
superans.

Ramuli teretes et peticli dense pubescentes. Folia membranacea ae
longa 3-5°™ lata leviter disparia supra glabra subtus nervis venisque pine

s
basin limbi prodeunte, petiolis 1-3°™ longis. Panicula in exemplo unico, manco
suppetente 3-flora ut videtur, pedunculo 5™™ longo, pedicellis 11™™ longis-
Calycis tubus turbinato-campanulatus 7™™ longus atque latus pubescens. Petala
obovata 12™™ longa. Antherae crasso-oblongae 5.5™™ lonyae filamenta aequan
tes. Stylus 15™™ longus, stigmate hemispherico 1™™-diametrali. Alabastra
ignota.—C. arboreae Schauer proxima.

In silvis ad Buenos Aires, Comarca de Puntarenas, Costa Rica, Febr. 1892,
Tonduz (n. 443).

ree >}

1906] SMITH—PLANTS FROM CENTRAL AMERICA 205

Conostegia rhodopetala Donn. Sm.—Folia glabra coriacea oblongo-
lanceolata caudato-acuminata basi acuta integra triplinervia, Pani-
cula pyramidata decomposita, axibus primariis 4-verticellatis. Calycis
tubus campanulatus limbus conicus rostratus. Petala obovato-
orbicularia.

rbor, ramulis obtuse tetragonis, junioribus uti folia nascentia et panicula
leviter furfuraceis. Folia decussata in eodem jugo satis inaequalia 15-20%
longa 5-8" lata in caudam linearem 8-ro™™ longain desinentia, nervis paulo
supra basin egredientibus validis, duobus basalibus submarginalibus tenuibus
vem adjectis, venis transversis 4-6™™ inter se distantibus, petiolis 2-5°™

ngis. Panicula 15-20°" alta densiflora, pedicellis 7-12™™ longis, floribus
a ae Alabastra rostello 2-3™™ longo adjecto 9™™ longa 3™™ crassa. Petala
6™™ longa rosea. Stamina 12-14, antheris leviter arcuatis. Stylus 4™™ longus
Crassus, stigmate capitato.—Juxta methodum e Monographia clari CoGNIAUX
expositam apud C. Pittieri Cogn. collocari de

In sylvis ad- La Palma, Prov. San José, Crs Rica, alt. 1500-1800", Jul.
1895, Tonduz (n. 9702), Sept. 1896, Pittier (n. 10169), Maj. 1898, Tonduz (n.
12347).—Las Lajas, San Isidro, Prov. Heredia, Costa Rica, alt. r500™, Sept.
1900, Pittier (n. 14022).

Conostegia vulcanicola Donn. Sm.—Stellulato-pubescens. Folia
‘Supra glabrescentia subtus nervis venisque pubescentia lanceolato-
elliptica utrinque acuminata margine setulifera quintuplinervia, ner-
vis superioribus a basi remotis, Alabastra inter minima oblongo-
ovoidea medio constricta superne conica apiculata. Flores 5—6-meri.

Ramuli teretes. Folia nascentia utrinque ferrugineo-tomentulosa, provec
tiora supra pilosiuscula vel glabrescentia subcoriacea $-14%™ longa 3-5.5°™ Jata
in eodem jugo parum aequalia apice curvilineo-acuminata, nervis superioribus
T.5~-2.5°™ supra basin limbi a medio sece oe setulis marginalibus cito
caducis, petiolis tomentulosis 1. 5—2. ongis. Panicula pyramidalis tri-

crassa exrostrata basi subtruncata pube paiicelets vel glabrescentia. Petala
obovata 5™™ longa crenulata flava. Stamina 1o-12, antheris rectis 2™™ longis.
tylus 4™™ ] ‘ongus, stigmate non dilatato. Fructus urceolato-globularis 4™™
diametralis glabrescens in Sicco plumbeus.—Ad C. Cooperi Cogn. quibusdam
hotis accedens foliorum nervatione recedit.
In silvis ad Achiote in monte vulcanico Pods dicto, Prov. Alajuela, Costa
Rica, alt. 2200™, Noy. 1896, Tonduz nee ers 10840).

Miconia astroplocama Donn. Sm. ($TAMONEA Cogn. )—P ilis
Stellatis luteo-fuscis tomentulosa. Folia supra nitida subtus prae-
sertim ad nervos pilosa lanceolato-oblonga apice ee acuminata

2096 BOTANICAL GAZETTE [OCTOBER

basi acutiuscula valde disparia 5-nervia. Flores pedicellati terni
5-meri. Calyx lobatus petalis dimidio longior. Filamenta glabra,
antheris profundiuscule bilobatis.

Arbor, coma rotundata, ramulis teretibus et petiolis panicula calycibus dense
tomientulosis. Folia subcoriacea integra supra glabra et in herbario nigricantia
subtus inter nervos pilis e papilla ferruginea pluriradiatis conspersa, cujusque
paris folio altero 18-33°™ longa 5-12 lato quam minus breviter petiolatum 2-3-
plo majore, petiolis crassis 2-5.5°™ longis. Panicula pyramidalis foliis brevior
multiflora, cymulis trifloris, pedicellis 2-4™™ longis. Calyx anguste campanu-
laris 4.5™™ longus limbo haud dilatato 2"™™ latus, lobis parvis rotundatis eatus
tuberculo punctatis. Petala quadrato-oblonga 3™™ longa. Antherae lineares
inaequales 3-4™™ longae incurvae fere usque ad o.5™™ supra basin affixae.
Ovarium semiliberum 3-loculare, stylo 9g™™ longo. Bacca globosa 5"™ diam-
etralis stellato pilosa.

In silvis ad fundum Tuis vocatum, Prov. Cartago, Costa Rica, alt. 65°”,
Noy. 1897, Tonduz (n. 11438).—In silvis ad Las Vueltas, Tucurrique, Costa Rica,
alt. 7oo™, Dec. 1898, Tonduz (n. 12872).

Miconia nutans Donn. Sm. (§ LACERARIA Naud. )—Leviter fur-
furacea. Folia supra glabra subtus praetermissis nervis glabrescentia
obovato-oblonga cordato-acuminata in petiolum canaliculatum
attenuata subobsolete sinuato-denticulata 5-plinervia, venis trans
versalibus crebris, Flores 5-meri. Calyx medio constrictus. ‘Petala
lineari-oblonga, Ovarium 5-loculare.

Ramuli obtuse tetragoni et petioli panicula foliorum subtus nervi furfuribus
minutis glandularibus stellatis ferruginosi. Folia coriacea siccitate utrinque laete
viridia subtus primum furfuracea demum inter nervos furfurium reliquis rubro-
punctulata satis disparia 15-25°™ longa 7-10 lata, nervo utroque superior’
_ circiter 5" ™ supra .basin. limbi aomedio secedente, inferiore submarginali, venis
salibus angulu recto patulis simplicibus 3-5™™ inter se distantibus sub-
tus conspicuis, petiolis 2-3 °™ longis. Paniculae singulae vel ternae pyramiales
£18. sup . ' pi tant : ae SERRE otomae; florid sessilibus vel breviter
pedicellatis, bracteolis oblongis cito caducis. Calyx pallide furfuraceus = Be i
longus, tubo subgloboso, limbo dilatato 2.5™™ Jato usque ad medium in lobos
ovatos disrupto. Petala 4™™ longa 1™™ Jata utrinque truncata nervata. Antherae
vix 3™™ longae. Ovarium fere totum adnatum, stylo 7-8™™ longo. Bacca depresso-
globosa 3™™ alta 4.5™™ crassa 10-costata limbo 2™™ alto coronata.—M. aureoidt
Cogn. proxima. .

Comarca de Puntarenas, Costa Rica, alt. 1100™, Febr. 1897, Pittier, ad ripas
Rfo Coto (n. 11059), in paludosis secus Rfo Cafias Gordas (n. 11060).—In fundo
Cubilquits dicto, Depart. Alta Verapaz, Guatemala, alt. 350™, Oct. 1993) bei
Tuerckheim, n. 8522 ex Pl. Guat. &c., quas ed. Donn. Sm. Sub M. obovali Naud.
olim distributa.

eritlt

1906] SMITH—PLANTS FROM CENTRAL AMERICA 297

Blakea anomala Donn. Sm.—Folia obovato-elliptica abrupte
caudato-acuminata basi acuta quinquenervia breviter petiolata,
Pedunculi solitarii filiformes. Bracteae exiguae triangulares. Calyx
primum clausus deinde in lobos 4 tubum aces dirumpens.

Saprogena. Rami teretes, ramulis petioli aleaceo-furfuraceis. Folia
chartacea supra glabra subtus nervis laviter facture in eodem jugo satis inae-
qualia consimilia 5.5-10°™ longa 3-5.5°™ lata in caudam 1-1.5°™ longam
desinentia, venis transversis 0.5-1™™ inter se distantibus, petiolis 5-8™™ longis.
Pedunculi leviter furfuracei 3-6°™ longi, bracteis 1.5-2.5™™ longis inaequalibus
basi connatis, alabastris turbinatis, floribus praetermisso calyce 6-meris. Calyx
coloratus cum bracteis tenuissime furfuraceus, tubo campanulato 7™™ longo
totidemque lato, lobis deltoideo-ovatis intus densius furfuraceis. Petala obovato-
oblonga 14~—1 5™™ longa. Antherae pendulae connatae ovales filamentis rubris
6™™ longis bis superatae, calcare acuto. Stylus 7™™ longus.—Ad B. gracilem
Hemsl. habitu accedens ab omnibus congeneribus bracteis necnon calyce insig-
niter recedit.

In truncis putridis ad La Palma, Prov. San José, Costa Rica, alt. 1450-1550™,
Sept. 1896, Pittier (n. 10165), Sept. 1898, Tonduz (n. 12521).

Passiflora Salvadorensis Donn. Sm. (§ EUDECALOBA Mast.)—Folia
subtus glauca ima basi cuneata paulo infra medium biloba, lobis
divergentibus paulo longioribus quam latioribus rotundatis. Pedun-
culi petiolos subaequantes, Calyx basi patelliformis, segmentis lineari-
bus pedunculo bis terve brevioribus. Coronae faucialis fila petalis
aequilonga, corona basali 5-crenata. Gynophorum gracillimum.
Filamenta sicut styli perelongata.

Scandens — ramis angulatis. Folia circumscriptione quasi semiovata
8-9™ longa 6.5-8-5°™ lata membranacea subius iter nerves alomdulis magnis.
ocellata trinervia. lobis et sinu vix lobuiato uervo exeunte aristulatis, nervis
lateralibus angulo scmirecto divergentibus, wns eglandulosis 3-5°™ longis,
stipulis filiformibus. Pedunculi 2—< 3-ni medio filiformi-bracteati, alabastris e basi
truncata oblongis. Sepala 16™™ longa. Petala hyalina linearia 8™™ longa.

°rona faucialis filamentosa, filis uniseriatis linzaribus purpureis. Corona
mediana late tubulosa 3-4™™ alta plicata denticulata purpurea. Corona basalis
“2mm alta herbacea. Gynophorum 12™™ longum. Filamenta stylos subae-
quantia 8-9™™ Jonga. Ovarium age so-ovale 1™™ longum. Fructus ignotus.
—P. ornithourae Mast. affinis ncolis Calzoncillos facete dicitur.

San Salvador, Republ. del Siete Maj. 1905, Luis V. Velasco, n. 8887
ex Pl. Guat. &c. quas ed. Donn. Sm

Dendropanax querceti Donn. Sm.—Folia breviter petiolata lanceo-
lata apice curvilineo-acuminata infra medium sensim angustata

«

298 BOTANICAL GAZETTE [OCTOBER

calloso-denticulata. Umbella solitaria, pedunculo petiolis paulo
longiore pedicellos vix superante ima basi bracteoso apice in recep-
taculum ferrugineo-bracteolosum dilatato.

Glabrum dichotomo-ramosum. Folia coriacea 5—10°™ longa 3-4-plo longiora
quam latiora calloso-apiculata, nervis lateralibus utrinque 11-14, duobus infimis
submarginalibus longius acnecanane reticulis minutis, petiolis 4-10™™ longis.
Pedunculus robustus 6-12™™ longus, bracteis imbricatis scariosis ovatis mucro-
natis, Sea bracteolis pileaeformibus lanceolatis pulverulentis, umbella
unica simplice 12-18-flora, pedicellis 5-10™™ longis. Calycis tubus obconicus
Fs Si margo mucronulis denticulatus. Petala ovata 1-nervia apice inflexa
calycem aequantia. Stamina petalis aequilonga, antheris ovalibus. Discus 4
calyce gees liber. Styli in columnam connati. Fructus globosus 4-5"
diamet

In its ad El Copey, Prov. Cartago, Costa Rica, alt. 1800™, Mart.
1896, Mart. 1898, Ad. Tonduz (nn. 11826, 12196).

;

¢

Rondeletia aetheocalymma Donn. Sm. (§ ARACHNOTHRYX Benth.
et Hook,)—Glabra. Folia obovato-elliptica subabrupte acuminata
basi acuta. Stipulae lineari-oblongae mucronulatae. Corymbus
obpyramidalis trichotomo-cymosus, floribus pilosis. Calycis lobi
elliptici, altero ceteris inaequalibus 2-3-plo majore quam tubus
corollinus cylindricus bis breviore.

. Frutex 3~-4-metralis, ramis et foliis nitidis. Haec coriacea. 12-15°™ longa
5-7°™ lata, nervis lateralibus utrinque 9-11, venulis subimmersis, petiolis 9-1
longis, stipulis 6-9™™ longis. Corymbus terminalis folia superans, peduncvlo
4-11™ longo, axibus semierectis pubescentibus, primariis foliaceo-bracteatis
3-5-3.5°™ longis, secundariis r.5-2.5°™ longis, bracteolis linearibus 6—12™

“evzis glabris, floribus tetrameris, dichotomli Sessili, lateralibus brevissime
pedicellatis. Calycis tubus cano-scrivets, lobi glabrescentes, maximo 7™™ longo
* a lato. Corollae albae tubus 13™™ longus cano-pilosus, os nudum exannue

sas ae, lobi obvvato-rotundi undulati intus farinosi. Capsula depresso globosa
™m_diametralis pilosa polysperma.-—R. linguiformi Hemsl. proxima

Secus viam inter Sepacuité et Secanquith, Depart. Alta Verapaz, Guatemala,
alt. 550-g00™, Jan. 1905, Maxon et Hay (n. 3275).

Rondeletia stachyoidea Donn. Sm. (§ ARACHNOTHRYX Benth. et
Hook.)—Folia anguste lanceolata utrinque, praesertim sursum,
attenuata supra parce pilosa subtus strigillosa. Thyrsus spiciformis,
capitellis subsessilibus 2-3-floris. Calycis arachnoideo-pilosi lobi
lineari-lanceolati paulo inaequales. Corolla praeter lobos extus basi
barbatos glabra, Capsula parva.

gmm

L aes

1906] SMITH—PLANTS FROM CENTRAL AMERICA 299

Arbuscula ee ramulis appresse pilosis, internodiis, saltem
superioribus, brevissimis. Folia ro-16°™ longa 2--3.5°™ lata sursum tenuissime
acutissimeque attenuata supra cito glabrescentia, nervis lateralibus utrinsecus
circiter g longe ascendentibus subtus conspicuis, petiolis 5-1o™™ longis pilosis,
stipulis lineari-lanceolatis filiforme attenuatis 1.5°™ longis internodia superiora
aequantibus. Thyrsus terminalis g-11°" longus pilosus, bracteolis_lineari-
lanceolatis calycem aequantibus arachnoideo-pilosis, floribus subsessilibus
tetrameris. Calycis lobi 3-4™™ longi. Corollae albae tubus tenuis 8™™ longus
sursum leviter ampliatus, os nudum exannulatum, lobi rotundati. Capsula glo-
bosa 2™™-diametralis pilosiuscula polysperma.—R. gracili Hemsl. affinis differt
inter alia capitellis paene sessilibus paucifloris. *

Semococh, Depart. Alta Verapaz, Guatemala, alt. 600-goo™, Apr. 1905
(Robert Hay)

Rondeletia Thiemei Donn. Sm. (§ARACHNOTHRYX Benth. et
Hook.)—Pilosa. Folia parva lanceolato-elliptica utrinque, sursum
longius acutiusque, curvilineo-attenuata subsessilia supra scabriuscula
subtus cinereo-pilosa, Panicula sessilis parva ovalis, axibus racemi-
formibus vel cymuliferis. Calycis segmentum quartum lanceolatum
ceteris subulatis 3-plo longius.

Frutex, ramulis et panicula cinereo-velutinis. Folia 5-8°™ longa 2-2.5°™
lata supra punctulata, stipulis triangularibus subulato-acuminatis 3-4™™ longis.
Panicula terminalis s-6°™ longa foliaceo-bracteosa, axibus patentibus, bracteolis
linearibus 4-6™™ longis, pedicellis 1- -3™™ longis, floribus tetrameris singulis vel

2-3-nis, cymulis pedicellatis. Calycis pilosi segmentum maximum 5-6™™ longum
3Nervium, Corollae tubus pilosus tenuiter cylindricus 8-1o™™ longus, os nudum
exannulatum, lobi subrotundi 3™m longi crenati utrinque glabri. Capsula
globosa 5™™_diametralis pilosa lobis calycinis coronata, seminibus numerosis
oblongo-cubicis scrobiculosis.

Rio Chamelecén, Depart, Santa Barbara, ener alt. goo, Jan. 1888,
C. Thieme, n. 5276 ex Pl. Guat. &c. quas ed. Don

BipENs CorEopsIpIs DC., var. ici Donn. Sm.—Plerum-
que 5-foliolata, foliolis beastie lanceolatis subglabris, corymborum
axibus filiformibus, acheniis margine dense barbatis, aristis parce
hispidulis,

Prope ee ea — Alta Verapaz, Guatemala, alt. s§0™, Jan. 1995,
Maxon et Hay (n. 62).

Hectia ii Donn, Sm.—Paniculae rami abbreviati sim-
plices continue denseque racemoso-floriferi, racemis cylindricis, flori-
bus singulis. Perianthii segmenta acuta dubetounl pedicello bis
breviore adjecto bracteolam paulo superantia.

300 BOTANICAL GAZETTE [OCTOBER

Folia 3.5-49™ longa perlonge attenuata supra glabra subtus niveo-lepidota
spinis corneis inter se 5—1o™™ distantibus 1-3™™ longis crenulata. Scapus cum
panicula glaber in sicco purpurascens, vaginis supra oinochrois subtus niveis e
basi ovato-lanceolata longissime filiformeque attenuatis 7-9°™ longis internodia
superantibus. Panicula 5-64™ longa, racemis raro binis sueto inter se 3-7°™
distantibus 4-8°™ longis, bracteis 1.5-2°™ longis uti bracteolae 7-8™™ longae
lineari-lanceolatis, pedicellis 3™™ longis, floribus glabris. Perianthii segmenta dis-
creta ovato-lanceolata, exteriora 5™™ longa cum bracteis bracteolisque oinochroa,
interiora 6™™ longa alba. Florum masculinorum solum cognitorum stamina
perianthium aequantia, ovarii rudimentum glabrum.

n collibus declivibus ad flumen Quwililé prope Santa Rosa, Depart. Baja
Verapaz, Guatemala, alt. 1600", Maj. 1g05, O. F. Cook.

BALTIMORE, Mp.

A BACTERIAL DISEASE OF OLEANDER.
BacitLtus OLEAE (Arcang.) Trev.
CLAYTON O. SMITH.
(WITH FOUR FIGURES)
DvrRincG the autumn of 1905 some diseased oleanders were sent
from a nursery to the plant pathological laboratory of the University
of California. This disease has been occasionally reported as occur-

Fic. 1.—Oleander, showing knots on stem and leaf from natural infection.

ring on young oleanders in this state. The trouble affects the stem
and leaves (figs. 1, 2), forming large, hard, woody knots. These
knots were examined by Professor R. E, SmirH and found to contain
oil [Botanical Gazette, vol. 42

302 BOTANICAL GAZETTE [OCTOBER

numerous bacteria which were produced in small colonies in the
tissue. The general nature of the knot and the close botanical rela-
tionship of the oleander and olive immediately suggested to him that
the trouble might be caused by the same organism that produces
the so-called knot or tuberculosis of the
olive. The subject was assigned to the
writer for further investigation, The work
for the most part was done at the bacterio-
logical laboratory of the University, and
thanks are due to C. M. Harinc and Pro-
fessor A. R. Warp, of that laboratory, for
their courtesy and suggestions during the
investigation.

The olive knot is a disease of the
branches and leaves of the olive tree.
It occurs in Egypt, in the olive-
growing sections of Europe bordering
on the Mediterranean, and is also
found in California where the olive is
grown. The disease has been known
for many years and is even described
by Roman writers; but its bacterial
origin has only been recognized since
1886, when the organism was dis-
covered by ARCANGELI (1) and
SAVASTANO (2). It is found in the knots
in what may be called colonies. These
appear as clearer or more transparent spots
in the callus-like tissue. These growths
See fee have their origin near the cambium layet

Fic. 2—Leaves of ole. and at length become darker in color.
ander, showing knots from About this colony hypertrophy of the tissue
ee takes place, as a natural effort of the plant
to heal the injury caused by the bacteria. This same process of
healing would take place in mechanical injuries. The result is
that much soft, spongy tissue is formed that makes a rather
favorable place for new bacterial growth, which means a new

:
H
|

1906] SMITH—A BACTERIAL DISEASE OF OLEANDER 303
9

formation of callus tissue and hence an increase in the size of the
knot. :

These large knot-like growths of the olive may be found on the
leaves, branches, and trunks, few in number or in great abundance.
They must not be confused with those caused by insects, and they
are also distinct from the enlargements formed on the roots of the
Leguminosae by bacteria. Badly diseased trees show scant foliage,
limited growth, and occasional dead branches.

The cultural characteristics of the olive knot organism have been
studied by Savastano (5) and seem to agree quite well with those
observed during this study. The following is a portion of the trans-
lation of SavasTANo’s account of the disease as published by
PIERCE (7):

This microorganism is a bacillus of medium size; length three to four times
its width; it is isolated, but is sometimes joined into chains; the extremities are
slightly rounded off. In drops of bouillon it has a distinct movement. The
colony has a variable form, from round to oval, with a well-defined margin. In
the beginning it is uniformly pointed; later it forms one or two peripheral cir-
cles. It is whitish by reflected light, cedar color by transmitted light. The
bacillus lives well in ordinary culture media (bouillon, potato, gelatin, agar).
The culture has a relatively long life; cultures made in March were still living
in June. In short, degeneration begins in about three months. On potato it
lives very well and develops rapidly; the colonies are at first like so many round
dots, translucent straw color, which, as they develop, form on the surface of the
potato a uniform stratum, translucent, and of a deeper color. The bacillus
acquires greater dimensions. On gelatin plates it lives very well, with characters
and forms as above indicated. In the tubes of gelatin (a becco) the culture
presents the appearance of a uniform stratum, whitish, the margin finely bilobed,
reminding one of the margin of a leaf, the whole culture taking the form of a
Spatulate leaf. It is slightly dichroic. In tubes of agar (a becco) the culture
is identical with the preceding, the margin is less bilobed. The culture by needle
in gelatin presents a uniform, transparent, finely pointed appearance. On the
Surface of the meniscus the form is irregularly rounded, with a finely lobed margin,
as in the preceding.

In the study of the present disease, the organism was first isolated
from the oleander in the manner described below. Inoculations
were then made on the oleander and olive. Positive results were
obtained in all cases, No effort was made to try inoculations on
other Plants. Savasrano ( 5), however, failed to make successful
Moculation with the olive knot organisms on peach, plum, apricot,

Ad

304 BOTANICAL GAZETTE [OCTOBER

grape, fig, pear, apple, bitter orange, lemon, rose, Adzes excelsa, A.
pectinata, and Cedrus Libani. He did not experiment with the
oleander, however, or any other plant related to the olive.

inoculated in the

on tree

leaves; J,

on

a,

artificial infection from pure culture:

on olive caused by

IG. 3.—Knots

i

lass

5

on plants growing under g

c, large knot and smaller knots

open

1906] SMITH—A BACTERIAL DISEASE OF OLEANDER 305

It required considerable time in the writer’s experiments for the
disease to develop, though in a month’s time the first indication of
tissue enlargement could be observed. This continued to increase
until on the olive quite a knot was formed in two month’s time
(fig. 3). Often the infection did not produce such a large knot as indi-
cated in fig. 3, but smaller swellings of the tissue. In this inoculation
work agar cultures, 48 hours old, were used, except on one occasion
when a bouillon culture was tried. Either gave equally satisfactory
results, The visible effects of the inoculations showed sooner on the
oleander, but their size and the rapidity of knot-formation seems to
depend upon the rapidity with which the plant is growing, as has been
before observed by SavasTANo (4) in his study of the olive knot. The
organism grows on both the stem and the leaves. In one experi-
ment a leaf of an oleander near the top of the plant was inoculated
on the midvein; this inoculation grew well, and from it secondary
natural infections resulted on the stem. It was not difficult to trace
the new infections on the stem to the very base of the petiole of the
diseased leaf. Infection (fig. 4) took place probably through the
stomata and lenticels. Checks were used by making punctures with
a sterile needle, but these gave no knot formations.

The lesions and growth on the hosts were quite different. On the
Oleander at first there was a slight enlargement of the tissue that
became somewhat rounded at the point of infection. After a time,
as the new growth continued, there was a splitting of the epidermis
in a longitudinal direction, forming a cleft (fig. 4). After this a
spongy growth formed, which is rather dark in color and contains
humerous small colonies of the bacteria. On the olive there was the
same enlargement of the tissue as in the oleander, but the formation
of the new growth was much more rapid, regular knots being soon
formed by the growing out of the new tissue. This took place in
the olive rapidly, while in the oleander it was only in the advanced
Stages that this new callus tissue grew into a knot-like formation.

he knots on the olive agreed in appearance with specimens of the
typical knots as it occurs in California, and with the illustration as
given by Prerce ( 7), Broretti (8), and ERwin SMITH (9).

The original cultures were made from the diseased tissue of the

oleander by first cutting away the outside tissue with a scapel, steri-

306 BOTANICAL GAZETTE [OCTOBER

from

Fic. 4.—Knots on oleander leaves and stem caused by artificial infection

pure culture.

1906] SMITH—A BACTERIAL DISEASE OF OLEANDER 307

lized by flaming. When this was done, the small colonies could be
seen in the tissue as dark clear places; these were touched with a
sterile platinum needle, and a tube of ordinary meat bouillon was
inoculated. Several such tubes were inoculated from the knots, and
in about two or three days there was abundant growth. From these
tubes dilution cultures were made on agar in Petri dishes. Other
dilution cultures in Petri dishes were then made from ten of the
bouillon tubes, and the uniformity with which one form of colony
appeared in the Petri plates seemed to indicate quite conclusively that
this was the organism causing the disease. Transfers were then
made from these colonies to agar tubes and thence to various culture
media,

CULTURAL CHARACTERISTICS.—The organism was grown on the
ordinary culture titrated to +1.5 to phenolphthalin and grown at
room temperature,

Mor phology—The organism is a motile rod with rounded ends,
1.5-2.5X0.5-0.6m. It is usually solitary, but may occur in pairs.
Organism direct from the plant as well as from the pure culture
shows motility. The size as above given was from a preparation
made directly from the tissue.

A gar slant—On agar growth appeared in about twenty-four hours,
aS a very thin, grayish-white surface growth. This spread quite
rapidly over the surface, especially near the lower portion of the tube.
Sometimes small roundish colonies appeared at the side of the growth
along the stroke. In cultures a week old the growth is white by
transmitted and reflected light. The growth is very thin and scarcely
ages at first. The condensation water becomes clouded and

ite
Agar plate colonies,—On agar plates the colonies become visible
- after three days. The deeper ones are small, globose, or biconvex
with sharp entire margins, The surface colonies are larger and more
Spreading, circular in outline, whitish in color, and somewhat more
dense in center than at margin. The deeper ones often have a straw
or cedar color as observed by Savastano. The surface colonies
measure 2-4™™ jn diameter when four days old. They are more
vigorous than colonies in gelatin of the same age.

Glycerin agar.—Growth much the same as in agar, except more

308 BOTANICAL GAZETTE [OCTOBER
vigorous, and hence a thicker surface growth resulted. Numerous
small colonies also developed on surface. :

Gelatin stab—Growth takes place along the stab and also on
the surface of the media. The growth along the puncture was fili-
form; on the surface it was thin, spreading from the point of punc-
ture, the margin undulatory to lobate-lobular. No liquefaction.

Gelatin plate colonies—These appeared in two to three days.
The deep colonies much the same as those in agar Petri plates. Sur-
face colonies more spreading, forming a very thin growth with irregular
undulatory margins, some darker in color than surface colonies.
Surface colonies under low power showed the center to be denser
than the margin and finely reticulated. Toward the margin the
reticulations are much coarser than in the center.

Potato.—Growth was vigorous and characterized by always being
straw color. The growth was quite markedly raised above the sur-
face and soon covered the entire plug.

Bouillon.—In meat bouillon growth appeared after two days as
a fine granular substance that remained in suspension, The culture
is at first slightly acid to litmus, but becomes alkaline after two weeks.

Glucose bouillon.—Growth the same as in the meat boullion, with
the same reactions. The change from acid to alkaline reaction 1S
much slower than in the other media.

Saccharose bouillon —Growth at first more vigorous than in either
the bouillon or glucose bouillon; acid at first, neutral after seven
days, and alkaline in two weeks.

Lactose bouillon —Showed the same general characteristics as Sac
charose, acid at first, then neutral and alkaline after two weeks.

Litmus milk—Showed no change until ten days, when there was
a distinct alkaline reaction. No coagulation ever occurred. After
fifteen days the medium was quite blue, with a slight whitish precip
tate at the bottom of the tube, This was not granular, but sub-
gelatinous, and when shaken into solution settled again to the bottom.
In a tube two months old the liquid becomes very blue and alkaline.

Milk.—Showed no change except a slight yellowing in color.

Scarcely any experimental work was done in growing the Bacillus
at different temperatures. SAVASTANO (4) states the optimum tem-
perature for the olive knot to be between 32-38° C, and SMITH (9)

tg0% | SMITH—A BACTERIAL DISEASE OF OLEANDER 309

has still further restricted the limits of best growth to between 35-
37-8° C. Several experiments were conducted by the writer with
the oleander organism in temperature about 35.5° C, and no growth
took place on agar, bouillon, or potato after four days, although
there was good growth in the inoculated bouillon tube at room
temperature.

All the liquid media become at first acid to litmus, but change
to an alkaline reaction in about two weeks. The media used were
all titrated to +1.5 to phenolphthalein. This would be slightly
alkaline to litmus, so the growth of the organism caused first an
acid, then an alkaline reaction. All the cultural characteristics of
the oleander organism, so far as possible, were compared with those
described from the olive organism. There seems to be a very close
agreement, and without question the organism is identical.

From knots produced by artificial inoculations on olive and
oleander the organism was isolated (in the same manner as described
before) and grown in the same media as was the original culture
from the oleander. These two series agreed perfectly in culture
characteristics with one another and with the original culture.

The organism also was isolated from naturally infected olive
knots in the same manner as for the oleander. Growth on various
culture media showed biochemical and cultural characteristics that
agreed with those observed by the writer for the oleander knot; and
with those described by Savasrano in his study of the olive knot.

This oleander disease is not believed to be a new trouble, but
Similar to the one found on olives. They are both caused by a
motile rod (Bacillus) that grows well on the ordinary culture media,
and will cause infection of the olive and the oleander. This infec-
tion at length causes characteristic lesions and knot-like growths on

_ the stem and leaves, The knots produced on the olive by the oleander
organism agree with typical knots as found on cultivated olives in
California, and with various illustrations of the olive knot. » The
cultural characteristics of the two are similar in all essential respects.

LaBoraToRY OF PLANT PATHOLOGY,

University of California, Berkeley.

310 BOTANICAL GAZETTE [OCTOBER

LITERATURE CITED.

I. ARCANGELI, G., Sopra la malattie dell’ olivo detta volgarmente rogna.
Pisa. 1886.

2. SAvAsTANO, L., Les maladies de l’olivier et la tuberculose en particulier.
Compt. Rend. 103:1144

, Les maladies de Volivicr, hyperplasies et tumeurs. Idem 1278.

1886.

4. , Tuberculosi, perplasie e tumori dell’ olivo. I e II Memoria. Naples.
1887.

5. , Il baccillo della tuberculosi dell’ olivo, nota suppletiva. Rend.

cee 5: 92-94. 1889.
6. Prituevx, E., Les tumeurs & bacilles de l’olivier, etc. Compt. Rend. 108:

249. 1891.
7. Pierce, Newton B., Tuberculosis of the olive. Jour. Mycol. 6:148-153-
I

%

81. ;
Broterti, F. T., The olive knot. ‘Calif. Agric. Exp. Sta. Bull. 120. 1898.
9. Smita, Erwin F., Bacteria in relation to plant diseases. I: 10. 1905.

CURRENT LITERATURE.
BOOK REVIEWS.

Another botanical dictionary.

Tuts Italian book is in a measure both a dictionary, with its mere definition
of terms, and an encyclopedia, with its more elaborate treatment of topics and
brief biographies of celebrated botanists.' In its plan, therefore, it departs
widely from Jackson’s Glossary; and it departs from it still more widely in
mechanical execution. For it is published by Urrtco Horpit of Milan whose
series of dictionaries and manuals is famous. It is 11X16°™, printed on thin
flexible paper, with narrow margins and small but clear type, bound in half vellum,
and though it contains nearly a thousand pages it is less than 4°™ thick. Eve
detail is appropriate to its use and the book is therefore a model of convenience.

In substance the work is unexpectedly good. The definitions of the simpler
terms are usually clear and succinct, and the treatment of topics is full enough
and is accompanied by citation of enough of the important literature to make the
book of real value for reference. A few figures will indicate the extent of some
topics. Thus to nutrizione are devoted nearly 36 pages; to fessuti, 10 pages;
to simmetria, 6 pages; to variazione, 7 pages; to germogliamento, 6 pages; to
classificazione, 8 pages; and so on. On the whole the assignment of space is
made with good judgment.

: The only adverse criticism that need be made is that the author has appar-
ently not always assimilated fully the modern morphology that he is endeavoring
to state. In consequence seeming contradictions and limitations occasionally
appear. Thus the sporofito seems to belong only to ferns and spermatophytes;
while the sporogonio appertains to the bryophytes. Sporangio is defined and
discussed only with ses to pteridophytes, and spore would seem to be
restricted to “ cryptogams.’ et in other topics the Rane of the micro-
spores of ELIE are recognized and properly described, while the
alternation of generations and heterospory are concisely but clearly treated.

On the whole there are probably as few shortcomings as could be expected

and as many excellences as could be attained by any one who undertakes such a

task. Cooperation, however, is fast coming to be Recesnery in work of such a
scope.—C. R. B.

hgeRe sa Eve., chains di botanica generale. Milano: Ulrico Hoepli.
16mo. pp. xx+926. Lt

311

312 BOTANICAL GAZETTE [OCTOBER

MINOR NOTICES.

Botanical papers at the St. Louis Congress.—Volume V? of the series being
published by the Congress of Arts and Science held in connection with the St.
Louis Exposition contains the botanical papers. The department of biology
was divided into eleven sections, and twenty-five principal papers were read.
Those of special interest to botanists, in the order of their appearance in the
volume, are as follows: Development of morphological conceptions, Joun M.
Covutter; The recent development of biology, JAcguEs Lors; A comparison
mt saical and natural selection, Huco pEVriEs; The problem of the

origin of species, C. O. Wuitman; Plant morphology, F. O. Bower; The
fundamental problems of present-day plant morphology, K. GOEBEL; The
development of plant physiology under the influence of the other sciences, J.

IESNER; Plant physiology, present problems, B. M. Duccar; The history
and scope of plant pathology, J. C. ARTHUR; Vegetable pathology an economic
science, M. B. WartE; The position of ecology in modern science, O. DRUDE;
The problems of ecology, B. L. Ropertson; Relations of bacteriology to othet
sciences, E. O. JorpAN; Some problems in the life history of pathogenic micro-
organisms, THEOBALD SMITH

All of these papers have a published in various journals, notably in
Science, but i ‘ is convenient to know that they are all accessible in a single
volume.—J. M. C.

Index Filicum.—The eleventh fascicle of CHRISTENSEN’s work has just
appeared,3 carrying the references from Trichomanes Giesenhagenii to the end :
of the list. There follow a list of additions, a list of corrections, and the begid-
ning of a catalogue of literature arranged alphabetically -—J. M. C

Trees of Java.—Koorpers and VaLeTon+ have published another fascicle
of additions to the known arboreal flora of Java, containing the Moraceae.
Seven genera are represented, including 95 — 83 of which belong to Ficus,
under which two new species are described.—J. M. C.

peraceae.—The second part of HusNot’s synopsis of the Cyperaceae
of France, Switzerland, and ae has te 5 completing the list of species,
and closing with a full index._J. M

2 Congress of Arts and Science, Universal Exposition, St. Louis, 1904- Edited
by Howarp J. Rocers. Volume V. Biology, Anthropology, Psychology, Sociology:
pp- xi+882. Boston and New York: Houghton, Mifflin and Company. 1906

3 CHRISTENSEN, C., Index Filicum, etc. Fasc., 11. Copenhagen. H. Hagerup.
1906. 3s. 6d.

4 Koorpers, S. H., and Vateton, TH., Boomsoorten op Java. Bijdrage no- T™
Mededeel. Depart. Landb. no. 2. pp. 277. Batavia, 1906.

5 Husnot, T., Cypéracées: descriptions et figures des Cypéracées de ee
Suisse et Belgique. Part II. pp. 49-83. pls. 13-24. Cahan, par Athis (Ome:
author. 1906. 5/r.

ce,

the

1906] CURRENT LITERATURE 313

NOTES FOR STUDENTS.

Mosaic disease of tobacco.—In an extensive account of the mosaic disease
of tobacco, which he has been investigating for a number of years, HUNGER®
deals somewhat radically with the theories that have been advanced to account
for the disease, and gives, as he believes, a new explanation. The earlier bac-
terial theories of Mayer, PritttEux, DELAcrorx, and others are treated only
as matters of historical interest, since they are based on insufficient evidence.
The more recent work of IWANOWSKI receives a more extended notice, although
his view of the bacterial nature of the disease is likewise refuted, as HUNGER
has been unable in his own investigations to corroborate IwANowSKI’s work.
BEIJERINCK’s theory that the disease is caused by an active fluid substance, itself
capable of growth, is discredited on the ground that BEIJERINCK was unable to
show that the virus was able to increase in quantity outside of the plant, and
that his proof of the fluid nature of the virus (diffusion in agar) is not sufficient.
Against the enzyme theory of Woops the author raises two principal objections:
(t) the transferability of the disease without limit does not accord with the
properties of enzymes, whose activity is diminished by extreme dilution; (2)
the virus of the mosaic disease has the property of being able to diffuse through
parchment, a property not possessed by enzymes.

HUNGER advances the view that the mosaic disease is due exclusively to dis-
turbances of metabolism, the outward manifestation of which is the peculiar
form of variegation seen in the leaves. That the mosaic disease, to whatever
cause it may be attributed, is a result of disturbances of the metabolic processe:
of the plant is beyond cavil; how this stat t brings us any nearer t pl a
tion of the ultimate cause of the disease is beyond our comprehension. The
author regards the disease as a sort of latent property possessed by tobacco
plants, in which it may develop spontaneously if conditions are favorable, or to
which it may be communicated by grafting and other methods. It is to be
regarded as a kind of communicable variability! The active cause of the disease
he regards as a toxin normally produced in the plant, but not injurious except
under special conditions, when it accumulates in excess of the normal amount.
The toxin is not like BEIJERINCK’s substance, capable of active growth, but is
capable, when entering into a normal cell, of producing there catalytic effects,
in consequence of which the toxin is there regenerated secondarily. In the
words of the author, it is physiologically autocatalytic, all of which is perhaps
merely a more extended theoretical explanation of what is ordinarily termed
Srowth. HUNGER discusses also the etiology of the disease, and the probable
telation of the methods of selection of tobacco practised at Deli to the rapid
increase of the disease in the Sumatra tobacco districts. He points out that in
order to obtain a high grade wrapper-leaf it has for generations been the practice
of the tobacco growers to select for seed the plants with the thinnest leaves. This
rn

“ *Huncer, F. W. T., Untersuchungen und Betrachtungen iiber die Mosaik-
rankheit der Tabakspflanze. Zeitschr. Pflanzenkr. 15:257-311. 1

314 BOTANICAL GAZETTE [OCTOBER

selection has resulted in a race of plants degenerate from the standpoint of their
power to resist unfavorable conditions. In the fields, even under usual condi-
tions, a large percentage of the plants wilt on hot days. The reduction of thick-
ness of the leaf is held in large measure responsible for the occurrence of the
mosaic disease. A lesser though important influence is also attributed to the direct
action of the soils —H. HAsSsELBRING.

Microsporangia of Pteridosperms.—In 1905 Krpstron published a prelimi-
nary note on the occurrence of microsporangia in connection with the foliage
of Lyginodendron.? He has now published the full paper,® with detailed dis-
cussion and illustration. He first elaborates the evidence that Sphenopteris

éninghausi Brongn. and Lyginodendron Oldhamium Williamson are identical
plants, and of course Crossotheca Héninghausi is the fertile pinnule of the former.
It follows that the sporangia found on this species of Crossotheca are the micro-
sporangia of Lyginodendron Oldhamium, a well-known pteridosperm. This rules
out Miss Benson’s claim that Telangium Scotti represents the microsporangia
of this Lyginodendron.

The microsporangia are borne on modified pinnae, associated with sterile
pinnae. The fertile pinna is oval, entire, on a short thick pedicel, and on the
under side of the blade six to eight fusiform bilocular sporangia are borne, which
bend inward at an early stage so that their pointed apices meet, forming a asi
of hemispherical sorus. Later they spread apart and appear as a fringe hanging
from the margin of the pinnule. In all cases the microspores are present, but
internal structure seems to be evident. The genus Crossotheca contains eight
species, a new one being described in this paper, and perhaps it is safe to assume
that all of them belong to the pteridosperms.

In a general discussion of the occurrence of fern-like plants, Krpsto
to the conclusion that the pteridosperms (including all Cycadofilices) are
undoubtedly the oldest group of fern-like plants of which we have evidence,
being plainly represented in the upper Devonian; that in the Lower Carbonu-
erous pteridosperms were still dominant, true ferns being feebly represented,
if at all, by the Botryopterideae; that in the Upper Carboniferous the same
relative representation continued. It seems highly improbable, therefore, as
the pteridosperms could have descended from true ferns, and KrpsTon is inclined

N comes

to believe that there is no more relationship between the two groups than that
of a common ancestry for pteridosperms and eusporangiate ferns. In er
ferns a

up his conception of the most probable lines of descent of the existing ‘
cycads, he indicates three lines: an independent one, leading from Botryopterideae
(of unknown origin) to the leptosporangiate ferns, and two lines converging 12
common but unknown ancestral forms, one leading to the Marattiaceae, the other
through pteridosperms to the cycads.—J. M. C.

7 Bor. GAZETTE 41:219. 1 ‘ arks

8 Kipston, Rosert, On the microsporangia of the Pteridospermae, with ar ve 13-
on their relationships to existing groups. Phil. Trans. Roy. Soc. London B. 198:4
445. pls. 25-28. 1906.

1906] CURRENT LITERATURE 315

Experiments with Hieracium.—OsTENFELD and ROSENBERG have under-
taken a series of experimental and cytological studies of the species of Hieracium.
RoseNBERG has published? a preliminary report of some of his results; but the
first paper of the series has just been received. It is by OSTENFELD,’° reporting
the results of castration and hybridization experiments. The castration experi-
ments, carried on in 1903, 1904, and 1905, resulted in showing that in the genus
Hieracium there are apogamous species, non-apogamous species, and transition
species, and that the three subgenera conform in a general way to this division;
Stenotheca having typical fertilization (the most primitive stage); Pilosella being
intermediate, with both apogamous and non-apogamous species (the former in
the majority); and Archieracium being entirely apogamous (except the H.
umbellatum group). Attention is called to the fact that Taraxacum has “gone
a little farther,” all its species being apogamous.

The hybridization experiments are only in their inception, but the following
results may be noted: a hybrid was produced between H. pilosella and H.
aurantiacum, with greatly reduced fruiting power; H. excellens, itself probably
a natural hybrid and producing only abortive pollen, gave hybrids by crossing
with H. aurantiacum and H. pilosella; the hybrids arising from the same cross
are heterogeneous; the fruiting power of hybrids is very slight.—J. M. C.

Infection experiments with mildews.—REED*"* has added a further contribu-
tion to the work inaugurated by NEGER and extended by Marcuat and SALMon,
bearing on the transferability of physiological forms of the Erysipheae from one
specific host to another within a closely related group of plants. The results
in general confirm the conclusions of previous investigators; namely, that there
exist races of E. graminis and other species of mildews which have become
specifically adapted to a single species, or more rarely to several species of one
genus of host plants. Reep finds, for example, that E. graminis from Poa
pratensis will not infect other species of Poa except in some instances. Thus
P. nemoralis is sometimes infected, while P. trivialis and P. compressa are infected
very rarely. By this and other investigations the fact that a high degree of speciali-
zation exists in the e Erysipheae, 2s in other groups of fungi, has been definitely
established. While further demonstration of the existence of biological races
is of less importance, the facts ascertained in this field of research furnish an
excellent basis for other investigations, as for instance, the question of the per-
manency of these races, the problems connected with abnormal predisposition of
the host plants, and others, some of which have already received attention.
-—H. Hasserprine.

° Ber. Deutsch. Bot. Gesells. 24: 1906.

7° OSTENFELD, C. H., Ex xperimental - se i studies in the Hieracia.
I. Shinde and eons expermients with so sae aa of Hieracia. Bot.
Tidssk. 27: 225-248. pl. 6.

** REED, GEorGE M., esas experiments with Erysiphe graminis DC. Trans.
Wis. Acad. Sci. 15:135-162. 1905.

316 BOTANICAL GAZETTE [OCTOBER

Turgor in yeast.—PANTANELLI having examined the regulation of turgor
in certain fungi and distinguished ‘‘cell pressure”’ into two factors, (1) osmotic
pressure or turgor, due to solutes, and (2) tension, due to imbibition, has investi-
gated by the same methods the turgor regulation in yeast derived from Roman
bread.'? He finds that during fermentation turgor at first increases, then remains
constant, and finally diminishes when the nutritive value of the medium becomes
much lowered. The power of osmotic regulation depends primarily upon nutri-
tion. If the foods are temporarily removed without altering the concentration
of the medium, the turgor and the tension diminish rapidly, the plant being
compelled to use its own reserves, forming vacuoles. If grown in water or
allowed to dry slightly, turgor diminishes, but the tension increases, in the first
condition until death, in the second up to a maximum, after which it diminishes
greatly before death. With age the power of osmotic regulation is gradually
lost. Aeration facilitates it so much that it seems admissible to say that the
Roman yeast lives during and after fermentation only because it falls into a state
of narcosis more or less profound.—C. R. B.

Blast of rice.—MetTCcALr’3 has recently published an account of the “ blast” of
rice with short notes on other rice diseases. This blast is characterized by lesions
at one or more of the nodes of the stem above which the stem dies. It has often
been confused with other diseases or injuries and the true extent of its damage
not realized. The disease is promoted by resting the land or by applying nitro-
genous fertilizers. It can be produced in healthy plants by inoculations directly
from diseased plants, but the organism causing the disease has not yet been fully
determined. The use of lime and marl with potash and phosphorus is recommend-

ed as fertilizer treatment that tends to reduce the tendency to blast. The disease
is prevented by spraying with Bordeaux mixture, but this treatment is not prac-
ticable with this crop. The search for immune plants has been of no avail up to
this time.—E. Mrap Writcox.

A new chestnut disease. —-Murriu" has described a new and serious disease
of the native chestnut, which is epidemic in many parts of New York City and
threatens to destroy all the chestnut trees of that region. The disease is also
known to occur in New Jersey, Maryland, District of Columbia, and Virginia.
“The fungus attacks twigs, branches, and trunks, irrespective of size oF posi-

tion, and usually proceeds in a circle about the affected portion until it is com-
_ girdled.” It is described as a new species of Diaporthe (D. parasitica).
eae A Se

12 PANTANELLI, E., Richerche sul delle cellule dj ievito. Annalidi Botanica
4:1-47. 1906. -

13 — H., A preliminary report on the blast of rice, with notes on other
rice diseases. Bull. N. ‘Car. Exp. Sta. 12t:1-43. 1

go6.
14 seine W. A., A new chestnut disease. Torreya 6: 186-189.

1906] CURRENT LITERATURE 317

Haustorium of Santalum.—BarBeEr’s has begun the publication of a series of
papers on root parasitism, the first one dealing with Santalum album, giving an
account of the early stages of the haustorium as far as penetration into the host’s
tissues. This is a somewhat fuller account than that oo by the author in
the Indian Forester and noticed in this journal.*® second paper is promised
which will describe the structure of the mature eects Investigation of
the mutual influence of host and parasite is also in progress.—J.

A new red clover.—Branp’’ has published the results of a study of a red
clover not hitherto used in the United States as a forage plant. The seed is from
Orel, in the “Black Earth” region of Russia, and the plant possesses advan-
tageous qualities that make its introduction desirable. Perhaps its most striking
mark in the field is the almost complete lack of hairiness; but it is the general
leafiness and the persistence and number of basal leaves that suggest for the new
variety the name T. pratense foliosum Brand.—J. M. C.

Plant diseases in Nebraska.—HerAtp*® has published notes on the distribution
and severity of numerous diseases of cultivated plants in Nebraska during 1995,
together with suggestions as to treatment of the various troubles. This in a way
constitutes a handbook of plant diseases in Nebraska. He has also published an
account of a rot of apples due to Sclerotinia jructigena,’® and a disease of the
cottonwood due to Elfvingia megaloma,?° once a member of the genus Poly-
porus.—E. Mrap Witcox.

Pteridophytes of southern Florida.—Eaton?* has put on record his observa-
tions on the pteridophytes of southern Florida during three excursions
purpose is to bring together the little-known species, with careful descriptions,
so that they may be more readily recognized by students of the flora € paper
is also a contribution to geographical distribution. Most of the stants described
are ferns, among which is a new species of Tectaria.—J. M. C.

*s BarBer, C. A., Studies in root parasitism. The haustorium of Santalum album.
1. Early stages, up to penetration. Memoirs Depart. Agric. India I:no. 1. pp. 30.
pls. 7. 1906.
‘© Bor. GAzETTE 40: 159. 1905.
17 BRAND, CHARLES J., A new type of red clover. U.S. Dept Agric., Bureau PI.
Ind., Bites ins Pp- 45. pls. 3. 1906.
ALD, F. D., Report on the 6a diseases uses in Nebraska during the
Season = 1905. Hep: Neb. Exp. Sta. 19: 19-81
79 HEALD, F. D., The black rot of a noe to Sclerotinia jructigena. Rep.
Neb. Exp. Sta. 19: 82-91. pls. 1-2. 1906.
2° HEALD, F. D., A disease of a cottonwood due to Eljvingia megaloma, Rep.
Neb. Exp. Sta. res 92-100. pls. I 1906.
at Bat Any Pte aad observed pars Hates Spciisings teks webert
Florida. a pon Bot. Club 33: 455-486. 1

318 BOTANICAL GAZETTE [OCTOBER

Pollen tube of Houstonia. MATHEWSON”? has studied the advance of the
pollen tube in Houstonia, coming to the conclusion that any mutual influence
between the tube and the cells with which it comes in contact is very slight;
and that the direction of the advance of the tube seems to be chiefly in response
to a stimulus originating in the egg apparatus, perhaps in the egg itself —J. M. C.

Operculina.—Housr?3 has published a synopsis of the genus Operculina
as the second paper of his series on North American Convolvulaceae. It com-
prises about twenty tropical species, which are perhaps better known to many
botanists under Convolvulus and Ipomoea. In North America fifteen species
are recognized, two of them being described as new.—J. M. C

Influence of temperature upon flowering of fruit trees.—Ecologists and
physiologists will be interested in the phenological notes presented by SANDSTEN**
relative to the influence of temperature and other factors upon the time of flower-
ing of certain fruit trees. He reaches the conclusion that “physiological constants
can be formulated from the climatic conditions during the ten months preceding
the time of flowering.” —E. Mrap Wixco

Effect of light on growth.—SrLpy?s has extended the work of MacDoucaL
‘to include four other species, mostly those which are latex-bearing. MacDov-
GAL’s conclusions that light does not have a retarding influence on growth and
that it does stimulate ph acre processes in the meristematic tissues are
confirmed.—RaymonD H. Pon

Varieties of roots developed by English ivy.—Miss RanpoxPx’? finds that
Hedera Helix may be induced to form in all seven kinds of roots according to
the conditions of moisture —RAymonpD H. Ponp.

22 MaTHEWsoN, C. A., The behavior of the pollen tube in Houstonia coerulea.
Bull. Torr. Bot. Club 33:487-493. figs. 3. 1906.

23 House, H. D., Studies in the N. Am. Convolvulaceae. Il. The genus Oper
culina. Bull. Torr. Bot. Club 33: 495-503. 1906.

24 SANDSTEN, E. P., Conditions which ota os time of the annual flowering of
fruit trees. Bull. Wisc. Exp. Sta. 137: 1-21.

25 SELBY, A. D., Studies in etiolation. Bull. Torr. Bot. Club 34:67-75- P poet
figs. 4. 1906.

26 DOLPH, Harriet, The influence of moisture upon the formation of roots
by cuttings of ivy. Bull. Torr. Bot. Club 34:93-09. figs. 4. 1906.

NEWS.

Dr. Ira D. Carpirr, Columbia University, has been appointed professor
of botany in the University of Utah, Salt Lake City.

Dr. Max K6rnickE, University of Bonn, has received the Buitenzorg grant
of the German government for 1906-7 and left for this station August 29.

Dr. C. A. J. A. OupEMans, the mycologist, emeritus professor of botany in
the University of Amsterdam, died recently at Arnhem at the age of eighty years.

Dr. D. H. Campsexz, Stanford University, has returned after an absence
of a year, some of which was spent in South Africa and the Botanical Gardens
at Peradeniya and Buitenzorg.

Mr. Leroy ABRAMS, of the Smithsonian Institution, formerly instructor in
botany in Leland Stanford University, has been appointed assistant professor
of systematic botany in the University.

Dr. Brapiry M. Davis will spend next winter in Cambridge, Mass. His
‘immediate work will be the completion with Mr. BERGEN of a laboratory and
field manual to accompany the Principles of Botany which has recently appeared
from the press of Ginn & Company. ‘

THE GRANTS made for scientific research at the York meeting of the British
Association include the following botanical grants: Physiology of heredity,
430; South African cycads, £35; Botanical photographs, £5; Structure of
fossil plants, £5; Peat moss deposits, £7; Marsh vegetation, £15.

THE AUTUMN couRSE of public lectures announced by the Field Museum
of Natural History, Chicago, contains two botanical titles as follows: October 20,
“The century plants, and some other plants of the dry country,” by Dr.
WiLtram TRELEASE; November 17, ‘Some phases of plant distribution,” by
Dr. J. M. Greenman.

Count OswaLp pe KERcHove DE DENTERGHEM, who upon the sudden.
death of Professor Lio ERRERA was appointed president of the International
Botanical Congress to be held in Brussels in 1910, died on March 20, at the age
of sixty-two. He was president of the Royal Society of Agriculture, and of the
Botanical Society of Gand, a senator, and ex-governor of Hainault.

AT THE University of Chicago, Dr. W. G. Lanp has been promoted to an
associateship, and Mr. L. L. BURLINGAME has been appointed assistant in mor-
Phology. Dr. FLorENce Lyon resigned at the close of the summer quarter,
and shortly thereafter was married to Mr. S. VINCENT Norton, of Akron, Ohio.
. The number of students registered for research work in the autumn quarter is
the largest in the history of the department.

319

320 BOTANICAL GAZETTE [ocroBER

AT THE CONCLUDING MEETING of the International Conference on Hybridi-
zation and Plant Breeding the Veitch gold memorial medals were presented to
Mr. W. Bateson, F.R.S., the president of the conference, Professor JOHANNSEN,
Professor Witrmack, and Professor MAURICE DE VILMORIN. Banksian silver-
gilt medals were awarded to Miss E. R. SAUNDERS, lecturer on botany at Newn-
ham College, and Mr. R. H. Brrren, for eminent services to scientific and prac-
tical horticulture —Nature.

THe Borantcat Socrety or AMERICA will meet in New York City in Con-
vocation week, beginning December 27, in affiliation with the A. A. A. S. This
meeting, the first after the union of the three constituent societies, will be an
important one, as questions of future policy are likely to be brought before the
society. The sessions will be arranged, in cooperation with the officers of Section
G, so as to avoid conflict. Members are requested to send to the Secretary
(Witt1AM TRELEASE, Missouri Botanical Garden, St. Louis), at the earliest
possible date, titles of papers and information as to time and any special facilities
required for their presentation. The total number of 1 t is 119.

HE BOTANICAL SUBJECTS for 1907 and 1908 announced for the “Walker
Prize,” offered annually by the Boston Society of Natural History, are as follows:
For 1907: The structure and affinities of some fossil plant or group of fossil
plants. The development of the gametophytes in any little known represen
tative of the Coniferales. The anatomy and development of some order or group
of the angiosperms.

For 1908: An experimental study of inheritance in animals or plants. A
comparative study of the effects of close-breeding and cross-breeding in animals
or plants. A physiological study of one (or several) species of plants with respect
to leaf variation. Fertilization and related phenomena in a phenogamous eee
What proportion of a plant’s seasonal growth is represented in the winter bud:

THE
BoTANICAL GAZETTE

November 1906

Editors: JOHN M. COULTER and CHARLES R. BARNES

CONTENTS

The Ovule and Female Gametophyte of Dioon
Charles J. Chamberlain

Temperature and Toxic Action Charles Brooks

The Embryogeny of Some Cuban Nymphaeaceae
Melville Thurston Cook

Current Literature

News

The University of Chicago Press
CHICAGO and NEW YORK
William Wesley and Son, London

Che Botanical Gazette

A Montbly FJournal Embracing all Departments of Botanical Science

‘Edited by Joun M. COULTER and CHARLES R. BARNES, with the an of other members of the
botanical staff of the University of Chic

‘Vol. XLII, No. 5 Issued November 17, 1906

CONTENTS

am OVULE AND FEMALE GAMETOPHYTE OF DIOON. ConTRIBUTIONS FROM THE
Hutt BorTanicaL LABORATORY, LXXXVI eich NINE FIGURES AND PLATES oie
Charles J. Chamberlain - - - 321

‘TEMPERATURE AND TOXIC ACTION (WITH THIRTY-THREE CHARTS). - Charles Brooks 359

THE EMBRYOGENY OF SOME CUBAN NYMPHAEACEAE (WITH PLATES XVI-XVIII);
elville Thurston Cook - ‘ : = 2 ‘ 3 : E Fi - . 396

CURRENT LITERATURE.

MINOR NOTICES - 4 Plaid Ph wm reg ety ted ee ee coe oe og Sh hay eld roel oo

NOTES FOR STUDENTS - : - - - - - ~ - bs Red md - 395
Sn eee reuters EP ae ae ee

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VOLUME XLII NUMBER 5

BOTANICAL ©Ga7et ee

NOVEMBER 1906

THE OVULE AND FEMALE GAMETOPHYTE OF DIOON.
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY.
LXXXVI.

CHARLES J. CHAMBERLAIN.
(WITH NINE FIGURES AND PLATES XIII-XV)

ONLY two of the nine genera of cycads have received any con-
siderable attention from morphologists. In these two, Cycas and
Zamia, the life history is fairly well known and many of its phases
have been studied in great detail. In Stangeria the development
of the sporangia has been investigated, and work on the remaining
six genera is fragmentary.

Through the courtesy of the Botanical Society of America’ the
Writer was enabled to visit the Mexican tropics for the purpose of
securing material of Dioon and Ceratozamia. The hearty coopera-
tion of Governor Troporo A. Denesa, who is an active educator
as well as a statesman, made it possible to collect an abundance of
material in a very short time. Mr. ALEXANDER M. Gaw, of the
State Bureau of Information, Xalapa, Mexico, had many collections
of material brought into Xalapa from the field and forwarded to
me after my return to Chicago. To both of these gentlemen I wish
to express my sincere thanks, since the investigation would have
been very limited without their efficient assistance. The photo-
staphs used were made by Dr. W. J. G. Lanp.

_The Subject will be treated under the following heads: I.
Dioon in the field; II. Material and methods; III. The ovule;
The female gametophyte; V. The microsporangium; VI.

The grant was made in December 1904 by the Botanical Society, at the St.
Louis meeting of the A. A. A. S., and was for the purpose of securing material for a
morphological study of Dioon and Ceratozamia.

421

322 BOTANICAL GAZETTE [NOVEMBER

Male gametophyte; VII. Fertilization; VIII. The embryo and
seedling. The first four are presented in the present paper; the
remaining subjects have been investigated and the results will be
published soon.

I. DIOON IN THE FIELD.

Dioon edule occurs in great abundance at Chavarrillo, about 25*"
east of Xalapa, the capital of the State of Vera Cruz. During March
1904 I made frequent trips through this region and, besides the
tedious work of preparing material, was able to make a few observa-
tions upon the plant as it occurs in the field. A second trip, devoted
largely to field study of both Dioon and Ceratozamia, was made in
September 1906. As the results of this trip will be published in a
separate paper, only a brief description of the general appearance of
Dioon is given at this time.

Associated with Dioon are occasional specimens of a large Opuntia.
Orchids and Tillandsias are not infrequent on the trees at the bottom
of ravines, though neither of these plants flourish on the rocky slope
where Dioon is at its best. In the lower portions of ravines several
species of Selaginella are abundant. Dioon is so abundant on the
rocky slopes that from a favorable point of view as many as a hundred
plants may be counted. Seedlings are numerous and one always
meets these and then small crowns before coming upon plants large
enough to bear cones. In spite of the seedlings, it is doubtful whether
the limited range is being extended.

In habit Dioon resembles Cycas revoluta (fig. 1). Some call it
the “Dolores palm;” but the natives are more likely to call it Tio
Tamal (“Uncle Tamal”), because they use the large endosperm
in making tamales. The largest plant measured had a trunk
nearly 3™ in height, and plants 1-1.5™ in height are not infrequent.
The trunk often rises obliquely, as shown in the figure, and as noted
in taxonomic descriptions.

The age of individuals —Even in the largest plants the leaf scars
are perfectly distinct over the entire surface, so that it is possible to
determine with almost absolute accuracy the total number of leaves
which a plant has borne. Professor Luis Murrtto has estimated
the age of individual plants by noting the number of leaves in a crown,
the duration of the crowns (two years), and the entire number of

1906]

Fic.

CHAMBERLAIN—OVULE OF DIOON 323

t.—Ovulate plant of Dioon edule on rocky hillside at Chavarrillo, Mexico;

the trunk is 1. «m hi

5 igh

224 BOTANICAL GAZETTE [NOVEMBER

leaf scars. From such data, the age of one plant with a trunk 1.45™
in height and 26°™ in diameter was estimated at 970 years. A small
plant only 21°™ in height is known to have been in cultivation more
than 4o years, and was presumably a fine specimen when brought
in from the field. In cultivation a crown may persist more than
two years, for the crown of a plant in the Washington Park (Chicago)
conservatory has remained vigorous for at least five years. It seems
probable that MuriILto’s estimate is conservative, and that many
of the large plants have reached an age of more than a thousand
years.

The trunk.—The trunk is always straight and shows no external
evidence of branching; among the thousands of plants observed,
one only showing definite branching. The specimen had a Y-shaped
trunk, each arm of the Y bearing a large crown. A few specimens
were seen with two, three, or four crowns; and one plant had five
and another six. The extra crowns do not come from loose buds
which might become detached, as is so commonly the case in Cycas
revoluta, but are all interlocked at the top of the stem. Some of
the extra crowns are probably due to injuries received in the removal
of cones, while others originate from the germination of seeds which
had not fallen to the ground but had remained in the nest of the
crown. Buds like those of Cycas revoluta also occur; occasionally
they are found near the bases of old trunks, and at the top they are
quite common. Some of these buds have well-developed crowns and
would doubtless grow into independent plants if they should become
detached and gain a suitable foothold. Root tubercles were observed
but they were infrequent.

The ovulate cones.—In 1904 fruiting plants were not abundant;
among plants large enough to bear cones not more than one in ten
was in fruit, and among these staminate plants were more numer-
ous than ovulate. In 1906 at least one-third of the larger plants
bore cones. I was informed that a plant fruits every other year,
and judging from the proportion of plants bearing cones in 1906 this
would seem true; but an estimate based upon the proportion. of
plants bearing cones in 1904 would make the interval very much
longer. The ovulate cones are large and ovoid (figs. 2, 3)- Cones
weighing 5** are common; and one large cone weighed 6** after

1906]

CHAMBERLAIN—OVULE OF DIOON

Fic. 2

—Ovulate cone 30¢™ in lengt
it arrived j os ;
ved in Chicago, more than two weeks after it had been taken
Tom the .
: the plant. This was a March cone and probably would have
Sained another kil f
lo before June. The length of the mature

I

21; some leaves have been trimmed away.

326 BOTANICAL GAZETTE [NOVEMBER

cone is 20-30°™, and the greatest diameter is 12-20". Young
cones picked November 1, 1904, five months before the cones reach
full size, weighed 1.5-2"* after reaching Chicago. The single cone
rests snugly on the plant at the center of the crown of leaves, the
peduncle being entirely concealed, so that it is difficult to remove

Fic. 3.—Ovulate cone 33°™ in length, showing position of ovules

the cone with a knife. The easiest way is to grasp the cone with
both hands and push it firmly to one side until the peduncle snaps
with a clean transverse break. After the seeds are ripe the peduncle
elongates somewhat, so that the cone often leans to one side, perhaps
facilitating the dispersal of seeds. There is a well-developed abscis-

1906] CHAMBERLAIN—OVULE OF DIOON 327

sion layer at the base of the petiole of the sporophyll, so that the
whole sporophyll drops easily when the seeds are ripe. A second
abscission layer, which separates the ovules from the sporophyll,
does not mature until a much later period.

Il. MATERIAL AND METHODS.

In March the ovulate cone has almost reached its full size, and
the staminate cone of the same season has decayed. The first
staminate cones were sent from the field on June 30, 1904. These
showed the four microspores still held together by the wall of the
spore mother cell. From this point to the discharge of the motile
sperms a complete series in the development of the male gameto-
phyte was secured. In the female gametophyte the series is com-
plete from the appearance of the archegonium initial to the germi-
nation of the seed. The series showing the development of the
embryo is very complete.

Nearly all the material was fixed in chrom-acetic acid in various
Proportions, with or without the addition of osmic acid. The fol-
lowing formula is excellent for the pollen tube structures and for
young ovules: chromic acid, 18"; glacial acetic acid, 4°°; 1 per cent
osmic acid, 2°¢; water, roo°*. This fluid will not penetrate the
microsporangia, and with older ovules it not only causes some plas-
molysis but makes the endosperm very hard to cut. After the
endosperm has become starchy, better results were secured by using
a slight modification of a formula suggested by Dr. Lynps JONEs:
5° per cent. alcohol, r00°°; commercial formalin, 6°°. This reagent
penetrates well and fixes rapidly. Iron-alum haematoxylin stains
brilliantly after it, but the safranin gentian-violet orange combina-
tion does not give as bright a stain as with material fixed in chromic
solutions. After this reagent, the starchy endosperm is not so hard
to cut. After the stony coat of the ovule has become hard, it is
almost impossible to cut it with any knife without injuring the arche-
gonia. For such stages the ovules were sawed in two transversely
with a fine wire-like fret saw. The upper part of the endosperm
with its archegonia was then trimmed into suitable shape for cutting.
The extremely thin blade of the Gillette safety razor, soldered to any
suitable handle, is particularly adapted for such trimming, since it

328 BOTANICAL GAZETTE [NOVEMBER

causes no damaging pressure as does the wedge-shaped blade of a
scalpel or ordinary razor. The nucellus usually remains within the
cup-like top of the ovule. Four strokes with a sharp scalpel will
cut through the nucellus against the stony background and remove
a piece containing the pollen tubes. Methods for studying the living
sperms will be given in a second paper. For showing the grosser
structures of the ovules, sections 4 or 5™™ in thickness were dehy-
drated and then cleared in xylol. For tracing the vascular bundles,
the pseudo-stalks of ovules were cut under water and the bases were
placed in eosin. The outer bundles soon become conspicuous on the
surface, and the inner bundles are easily traced by removing the
endosperm and scraping away the greater part of the inner fleshy
layer of the integument.

Most of the sections were stained in safranin and gentian-violet;
some were stained in iron-alum haemotoxylin. Magdala red and
anilin blue proved to be a good combination, especially for pollen-
tube structures, and it is quite convenient, since no clearing agent
is necessary, the slides being taken directly from the absolute alcohol
and mounted in Venetian turpentine. Overstaining in the Magdala
red can be corrected, even after the cover glass is in place, by exposing
the slide to direct sunlight for a short time.

III. MEGASPOROPHYLLS AND OVULES.

No other cycad, except Cycas, has such large and leaf-like mega-
sporophylls as Dioon (figs. 4-6). Both the leaf-like character of
the megasporophylls and their comparatively loose association in the
cone are more suggestive of Cycas than of Zamia or Ceratozamia,
which are the geographical neighbors of Dioon. The remaiing
occidental cycad, Microcycas, is too imperfectly described to allow
any comparison of the cones,

In Dioon the sporophylls at the base of the ovulate cone are
yellowish or greenish, with little hair except along the central portion
of the back. There are four or five turns of the spiral of these spore
phylls, followed by one or two turns of somewhat hairy sporophylls.
The remaining sporophylls are densely covered with long brown
hairs, the lower ones on the back and edges and a small portion of
the upper part of the inner face, and the rest not only upon the back

sae CHAMBERLAIN—OVULE OF DIOON 329

and edges but upon the entire upper half of the inner face. This
gives the whole cone a brown color and a densely hairy appearance.
It would seem impossible for the cone to be wetted by rains. The
changes in temperature in this region are so slight that the hairy
condition could hardly be related to this factor.

The lower greenish sporophylls never bear ovules or even primordia
ofthem. The next sporophylls have occasional primordia, but it
is only when the larger sporophylls are reached that normal ovules

ses 4-—Ovulate sporo- Fic. 5.—Ovulate sporo- Fic. 6.—Ovulate sporophyll,
Phyl, back and side view. phyll, inside view; ovules abaxial side; one ovule with
= essile. X 4. pseudo-stalk, the other sessile.

x}.
appear. Even the uppermost sporophylls bear ovules which some-
times ripen into seeds. The uppermost sporophyll is almost circu-
lar in transverse section. Its two ovules usually abort, as do those
of the next sporophyll below it, but from this point, down to the
sterile sporophylls at the base of the cone, each sporophyll bears two
ovules which may develop into seeds. The ovules in a cone number
about 100-300, and probably 200 ripe seeds is a liberal estimate for
the larger cones. Where plants are isolated and pollination is uncer-
tain, there are few ripe seeds, or even none at all. It would not be
Sale to say that the ovules of Dioon do not attain their full size unless
Pollination has taken place, for it is well known that the ovules of

330 BOTANICAL GAZETTE [NOVEMBER

other cycads reach their full size without the stimulus of pollination.
‘However, the only greenhouse cone of Dioon which has come to
my notice had only abortive ovules, and in the field the ovulate cones
at any considerable distance from staminate plants are likely to
contain only abortive ovules. Such ovules have not been pollinated.
In cones bearing ripe seeds the abortive ovules have usually been
pollinated, but have failed to develop from lack of room or of
nutrition. It is easy to determine whether pollination has taken
place, since the course of the pollen tubes is marked by conspicuous
brown lines upon the nucellus. ;

The youngest ovules secured in 1904 were sent from the field
November 1. These were 1°™ in length and showed the archegonium
initials. Only one small cone had ovules as young as this, the ovules
in other cones of this date measuring 1.5°™ in length and showing
the central cell of the archegonium. November 14, six weeks after
pollination, the average length of the ovules is about 2.3°"; in the
following spring (April 3), when the ovules had reached their full
size, the largest ones measured 4°™ in length and 2.2°™ in diameter.
The average length is about 3°", and the diameter 2°™. Many
ovules are nearly spherical, measuring about 3°™ in length and 2.8°™
in diameter. The ovules are perfectly smooth, and until nearly ripe
are white, but become cream-colored or yellowish when exposed to
the air; at maturity they have an orange color which contrasts
sharply with the pale yellow of the naked portion of the sporophyll.
They are sessile, but many of them appear to be stalked because
strains due to the growth of the sporophylls and ovules draw out
the base of the sporophyll into a stalk-like structure (jig. 5)-

The ovule of Dioon reaches its full size before the stony layer
becomes hard enough to occasion any serious difficulty in sectioning.
Median longitudinal sections 3 or 4™™ in thickness, well dehydrated
and cleared, but not stained, are best for a study of the general topog-
raphy (fig. 10); while fresh ovules whose bundles have taken up
eosin are most convenient for tracing the vascular system (jigs: 7; 9 9)-
The epidermis is smooth, strongly cutinized, and contains no stomata.
At the base of the ovule the abscission layer is marked by a distinct
constriction (fig. 10, @). The opening of the micropyle is amber Or
brownish in color from the drying of the pollination drop which,

1906] CHAMBERLAIN—OVULE OF DIOON 331

judging from the caliber of the micropyle, must be quite large, although
it was not observed directly. Early in November the various tissues
of the ovule are recognizable, and early in December the layers of
the integument are almost as distinct as in the following March,
although the cells of the stony layer have not begun to thicken, and
microtome sections of the entire ovule can still be cut. The general
topography of the ovule, as it appears later in December, is shown
in fig. zo. In this figure the endosperm and fleshy tissues are dotted,
the stony layer is more deeply shaded, and vascular bundles are
represented by dark lines. The integument conists of three layers,

7

Fic. 7.—Ovule photographed from above; the eosin has spread and exaggerated

the size of the outer bundles (0). X2.
1G. 8.—Inner vascular system of ovule, treated with eosin and photographed
after the endosperm and part of the inner fleshy layer had been removed: 7, bundles
of inner vascular system; m, micropyle; 0, bundle of outer vascular system; , basal
papilla; s, Stony layer. X2.

PYG gw T rarrcuras section of ovule treated with eosin: e, endosperm; #, bundle
of inner vascular system; m, inner fleshy layer of integument and fused portion of
hucellus; 0, bundle of outer vascular system; s, stony layer. X2.

an outer and an inner fleshy layer, with a stony layer between them.
Only a small portion of the nucellus is free from the integument.
The fleshy layers of the integument are comparatively simple in
structure.

The outer fleshy layer —The outer layer at the stage shown in jig.
17 is not sharply marked off from the stony layer. These two layers

332 BOTANICAL GAZETTE [NOVEMBER

cannot be split apart, and even as late as May, when the stony layer
has become very hard, the fleshy layer cannot be peeled off; it is only
after it has become somewhat dry that it can be peeled off from the
stony layer. However, the two layers easily separate as early as
December if an ovule is cut in two and then allowed to decay for a
few days in a damp atmosphere. The walls of the epidermal cells
are considerably thickened and the outer surface is strongly cutinized.
Most of the cells of the two layers just beneath the epidermis contain
tannin, which occurs in only less abundance down to the level of the
outer bundles. The cells containing tannin lie mostly in rows extend-
ing in the same general direction as the bundles. The large mucilage
canals lie between the bundles and also have a general vertical course,
but they branch and sometimes anastomose, so that some transverse
sections of the canals are found even in longitudinal sections of the
ovules. Beyond the zone of the bundles is a region of parenchyma
cells (fig. 11, p).

The stony layer—This layer, except at the deep pit which is occu-
pied by the basal papilla, is thickest at the base and thinnest at the
extreme apex. From the thin spot at the apex down to the lower part
of the free portion of the nucellus it is thicker than throughout the”
middle two-thirds of the ovule. While the stony layer of the ripe
seed is extremely hard, it is tougher and more elastic than the stony

-coat of most nuts, doubtless due to its complicated structure. The
outer cells of the layer are small and isodiametric (jig. 11, i). In
November they are not very sharply marked off from the inner cells
of the outer fleshy layer; in fact, it is only after the walls of the stone
cells have begun to thicken that the boundaries of the layers can be
determined with accuracy. Beyond the small isodiametric cells nae
irregular zone of cells elongated in a more or less longitudinal direction
(jig. 11, e); then follows a zone of similar cells elongated transversely
(fig. 11, et); and finally another zone of cells considerably elongat
longitudinally (fig. rz, 7). As growth continues, the small —
isodiametric cells simply increase in size and their walls became thick-
ened. In the cells of the other three regions there is not only an
increase in size and a thickening of the walls, but various displace-
ments occur, so that the structure in March is much more complicated
than in the preceding November. The elongating cells become

1906] CHAMBERLAIN—OVULE OF DIOON 333

crowded and interlaced and sometimes even branch, thus giving rise
to an extremely tenacious tissue,

The inner fleshy layer—This layer contains the inner vascular
system, but otherwise consists of rather uniform, slightly elongated
parenchyma cells. The cells are smaller than those of the main
body of the nucellus, but there is no definite boundary between them.
The boundary between the inner fleshy layer and the stony layer is
less indefinite, and as early as January the two layers may be peeled
apart, though with a rather uneven break. In small November
ovules the inner fleshy layer has about the same thickness as the stony
layer, but from this time the fleshy layer grows more rapidly, and in
early December ovules is much thicker than the stony layer (fig. 10).
The rapidly growing endosperm then begins to encroach upon the
adjacent cells, which we regard as nucellar tissue intimately united
with the inner fleshy layer of the integument, although it must be
admitted that the ontogeny shows no indication of such a union.
The encroachment continues until in the ripe seed all the tissues
between the endosperm and the stony layer is reduced to a thin dry
membrane, which peels off easily and cleanly, and shows very clearly
the distribution of the inner vascular system. The inner fleshy layer
is to be regarded as belonging to the integument rather than to the
nucellus, because it is continuous with the inner fleshy layer of the
free portion of the integument; because the bundles which it con-
tains often extend into the inner fleshy layer of the free portion of the
integument but never into the free portion of the nucellus; because in
half-ripe ovules the fused portion of the nucellus may be peeled away
from the layer containing the inner bundles; and, still more impor-
tant, because such a conclusion is warranted by a comparison of the
cycad ovule with those of fossil gymnosperms.

The phylogeny of the three layers.—This is an interesting question.
Has the single complex integument always been single, or does it
Tepresent two integuments which have become fused? This is a
question to which no definite answer can be given, because the early
development of the ovule has never received sufficiently careful study
in any cycad. The early stages in the development of the integument
are passed before the cone breaks through the scale leaves, and conse-
quently no material is likely to be secured in greenhouses. In the

334 BOTANICAL GAZETTE [NOVEMBER

field, where material may be abundant, it would be necessary to cut
out the growing points of many plants to secure a few ovulate cones.
And even then, judging from a slight examination of the ovule of
Ginkgo, the integument of which also has two fleshy layers with a
stony layer between them, we should be likely to find the integument
arising as a single undifferentiated tissue. A study of the integument
of Dioon after its various tissues have become somewhat differentiated
also fails to give any definite evidence as to its single or double nature.
_ [have been able to examine the integuments of several other cycads,
but even where the differentiation between the layers is sharp, as in
Zamia integrijolia, where the outer fleshy layer in both its cell-struc-
ture and cell-contents is sharply marked off from the stony layer, and
where the differentiation between the stony layer and the inner fleshy
layer is also rather distinct, there is no satisfactory evidence that the
integument has ever been anything but a single structure. In Cerato-
zamia the layers are even less defined than in Dioon.

Judging from the literature of the subject, especially from the work
of Miss Stopes (16), who has made the most thorough investigation,
no study of the integument of living cycads can yield conclusive evi-
dence as to its single or double nature. However, a comparison of
the cycad ovule with that of the fossil Lagenostoma lends much
strong support to the theory that the cycad integument is a double
structure. OLIVER and Scort'} suggest that the cupule of Lagenos-
toma is equivalent to the outer fleshy layer of the cycad integument,
while the canopy of a Lagenostoma may have become simplified into
the stony layer of the cycad seed. Miss Stopes’ opinion is indicated
by the title of her recent paper ‘‘On the double nature of the cycadean
integument.”*© She believes that the plane of fusion between the
two coats is either between the inner and outer portion of the stony
layer or between the stony layer and the inner fleshy layer. The outer
fleshy layer and the outer portion of the stony layer she believes
to be too intimately connected to be separated morphologically.
The structure of the Dioon integument, as it appears in sections,
would seem to indicate that the plane of union has been between the
inner and outer layers of the stone (fig. 11, et, i). The integument
of Ceratozamia would bear a similar interpretation; but in Zamia
integrijolia the outer fleshy layer is so sharply marked off from the

1906] CHAMBERLAIN—OVULE OF DIOON 335

stony layer that one could easily regard the former as an adnate
cupule equivalent to the free cupule of Lagenostoma. In spite of the
close morphological continuity between the stone and the outer flesh
during the early development of the integument of most cycads, the
two layers separate readily at maturity. The carpels of syncarpous
ovaries of angiosperms become so closely united that the planes of
fusion seem completely obliterated and the tissues appear perfectly
continuous, but at maturity the carpels separate along the original
planes of union. Hence the close continuity of the tissues should not
exclude the view that the outer fleshy layer of the cycad ovule repre-
sents a structure which has become adnate to the stony layer. On
the other hand, the ready separation at maturity must not be urged
too strongly as an argument in favor of a union at this plane, because
at maturity the inner fleshy layer of all the cycads also separates just
as readily from the stony layer, and the inner fleshy layer of the integu-
ment never separates at all from the lower portion of thé nucellus.
While it must be confessed that the cycadean integument itself offers
no conclusive evidence of a double nature, we agree with Miss Stopes
that it possibly represents a double structure. In regard to the plane
of fusion we could not agree with her, but think it more probable that
_ the union has taken place between the outer flesh and the stone.

Lhe nucellus.—The nucellus is free from the integument only for a
short distance, the free portion extending little beyond the top of the
endosperm. The free surface is cutinized and the epidermal cells
Contain tannin. When very thick sections are cleared in xylol, the
free portion is limited by a very conspicuous black line. The sharp
beak closes and hardens immediately after pollination, imprisoning
the pollen grains in the pollen chamber. After pollination the upper
Portion in the surface of the nucellus soon becomes marked by brown
lines caused by the haustoria of the pollen, which never penetrate
deeply, but lie just beneath the epidermis. In December a consider-
able mass of tissue separates the pollen chamber from the top of the
endosperm, in which the archegonial chamber has not begun to form.
Subsequent growth of the endosperm, together with extensive dis-
organization of nucellar tissue and also some enlargement of the pollen
chamber itself, finally destroys all tissues between the pollen tubes and
the archegonia. The mode of disorganization which results in the

336 BOTANICAL GAZETTE [NOVEMBER

formation of the pollen chamber is easily seen. The middle lamella
softens and breaks down, thus setting free a few cells which are soon
resorbed, and so forming the beginning of a pollen chamber. The_
subsequent encroachment of the disintegrating region is most rapid
downward, but is also increasingly extensive at the periphery, so that
the completed chamber is more or less funnel-shaped.

Below the free portion of the nucellus its most. conspicuous feature
is the thick jacket which surrounds the endosperm (fig. 11, ej). This
jacket is sharply differentiated from the rest of the nucellus, and is so

tenacious that it can be stripped off with forceps. The megaspore-
membrane sometimes adheres to it, but more often clings to the
endosperm. Although the material contained no early stages in the
formation of the jacket, it is evident that it originates as a layer only
one cell in thickness. Where cells of the layer do not divide peri-
clinally, it remains only one cell thick; if there is a single periclinal
division, the layer becomes two cells thick; while another division
would make it three cells in thickness. In the archegonial region a
considerable portion of the cells undergo one periclinal division;
while in the chalazal region nearly all the cells show such a division,
and a large number undergo a second periclinal division. On the
sides there is a gradation between these two extremes. The less
prominent and less complete jackets of the Coniferales have been
described by THoMSoN (21).

The cells of the jacket are very frequently binucleate and occa- -
sionally three nuclei are found. In comparison with the size of the
cell these nuclei are rather large, but their chromatin content is very
scanty and the nucleoli are small (fig. r2). It is not at all uncommon
in these cells to find a complete chromatic spirem lying perfectly free
in the cytoplasm, with no trace of a nuclear membrane or any achro-
matic structures (fig. 13). In such cases the nucleolus is always
present and is somewhat larger than that of resting nuclei. The
amount of chromatin in the spirem is vastly greater than in the resting
nuclei. This unique condition does not lead to the formation of
daughter nuclei or even to the reorganization of the single nucleus,
and the significance of the phenomenon is not evident. The cells of
the jacket at this time are centers of extreme metabolic activity,
all the materials for the nutrition of the rapidly growing endospe™™

1906] CHAMBERLAIN—OVULE OF DIOON 337

passing through them, and in passing undergoing some change before
reaching the endosperm. It may be that the peculiar nuclear condition
is brought about by the extreme activity of the jacket cells.

The walls of the jacket cells are suberized and stain deeply with
safranin, thus contrasting sharply with the cellulose walls on both
sides of them. The most conspicuous cell contents are irregular
granules and coarse strands, which stain so deeply with safranin that
in a section of a November ovule the jacket appears as a bright red
circle easily visible to the naked eye. The material of the granules
appears very much like that of the outer part of the megaspore mem-
brane, which Tomson (21) found to be a suberized structure. He
described similar granules in other cycads and found them to consist
of amylodextrin, but in his form the amylodextrin disappeared before
the stage represented in jig. 13 was reached. (There are no pits in
any of the cells of the jacket.) The irregular granules and strands
adhere closely to the cell wall even after the cytoplasm has been drawn
away by reagents, as shown in figs. 12 and 13. No granules or
strands are found on the outer walls of the jacket cells or in the cells
on either side of the jacket layer. The endosperm jacket differs
decidedly from the archegonial jacket in having no pits in the walls; _
Consequently, all substances must pass through the jacket by the
usual method of transferring material from one cell to another. _

The jacket is doubtless concerned with the nutrition of the struc-
tures within, like the jacket about the embryo sac of an angiosperm,
the jacket about the seeds of gymnosperms, or the tapetum about the
Spotogenous cells of microsporangia. While the jacket in all these
cases is concerned in nutrition, the mode of nutrition and the nature
of it are different. It is most active while the endosperm is still
Spherical. As the endosperm elongates and approaches its full size,
the jacket disintegrates, and at the stage shown in fig. ro it has broken
up and only suberized fragments remain. As to its morphological
nature, the jacket corresponds to the jacket or tapetum which sur-
tounds the sporogenous tissue of microsporangia. In a microspor-
angium the jacket surrounds a large number of spores, while in the
“ase under discussion it surrounds only one spore, which, at the stage
shown in jig. 10, has developed an extensive prothallium. Lane (12),
who secured early stages of this structure in Stangeria, describes an

>

338 BOTANICAL GAZETTE [NOVEMBER

extensive sporogenous tissue in the ovule, and believes that the outer
portion of it gives rise to the tapetum, while all the tissue within
except the functional megaspore disappears. Unfortunately, no such
early stages were secured in Dioon, but since the jacket surrounding
the microspores may originate from either sporogenous or sterile
cells, there seems to be no objection to regarding the jacket sur-
rounding the megaspore as equivalent to that surrounding the micro-
spores, especially since homosporous forms, to which all heterosporous
forms must ultimately trace their origin, have well-developed jackets.

Base oj the ovule——The lower limit of the ovule is marked super-
ficially by a slight constriction as soon as the abscission region begins
to develop (fig. 10, a). This region does not extend straight across,
but is depressed in the center, with the depression away from the body
of the ovule. When the ovule breaks off, the slight protuberance at
the base is due to the shape of the abscission zone. This zone, about
twelve cells in thickness, consists of nearly isodiametric cells, and
thus contrasts rather sharply with the elongated cells above and below
(fig. 14). Almost as soon as the zone can be distinguished, inter-
cellular spaces appear, which increase in size until they sometimes
become as large as the cells themselves, making them appear some-
what like the stellate cells of Typha, Scirpus, and similar forms.
These cells are rich in starch. Above the abscission region the axis
of the ovule extends upward and terminates in a conspicuous pro-
jection which occupies a deep pit in the stony layer. This projection,
which was described as the Einstiilpung by Miss Stopes (15), may be
called the basal papilla (fig. ro, p). In the unripe seed the tissue of
the basal papilla is noticeably tougher than that of other portions of the
outer fleshy covering. In the ripe dry seed it looks for a time like a
toothpick broken off in the stony layer, but it soon decays like the
rest of the fleshy layer and its place is marked by a conspicuous pit
about 2™™ in diameter and extending almost through the stone.
Large elongated cells containing tannin are abundant on both sides
of the abscission zone, but they do not extend into it. Several large
mucilage ducts, which lie within the region occupied by the vascular
bundles, reach almost to the top of the basal papilla. In the position
and shape of the abscission layer and also in the appearance of the
basal papilla, Dioon resembles Lagenostoma as described by OLIVER

1906] CHAMBERLAIN—OVULE OF DIOON 339

and Scorr (13) and illustrated in their fig. 26. The rest of the tissue
on each side of the abscission zone consists of large, elongated cells,
forming a loose parenchyma with irregular intercellular spaces like
those of the abscission zone, except that the spaces are larger.

Vascular system of the ovule——The distribution of the vascular
system is easily traced by cutting off the petiole of the sporophyll under
water and placing the cut end in an aqueous solution of eosin. The
vessels become filled with the solution in a few minutes. For study-
ing the course of the bundles in the ovule itself, it is better to cut the
ovule just below the abscission layer. While the fluid does not always
penetrate the ultimate tracheids, the course of the bundles is sharply
marked, as may be seen in figs. 7-9, which are photographs of ovules
treated in this way. For studying the transverse distribution of
bundles, series may be obtained very rapidly by cutting sections of
ovules treated with eosin and simply placing the sections in order
upon a sheet of paper. The abundant mucilage causes them to
adhere firmly, and the bundles appear as bright red dots.

A transverse section of the petiole of the megasporophyll near the
axis of the cone shows about seven bundles, arranged in a straight
line. Two of these bundles, one at each end of the row, are usually
larger than the others, and develop into the vascular systems of the
ovules. The other bundles branch repeatedly, so that in the widest
part of the lamina of the sporophyll a transverse section shows about
thirty bundles, still arranged in one straight line. The outer bundle
forks once as it passes to the ovule, so that a transverse section just
below the abscission line of the ovule shows two bundles. From each
of these two bundles a branch passes toward the outer fleshy layer of
the integument, and another branch toward the inner fleshy layer,
thus giving rise to an outer and an inner vascular system with the
stony layer lying between them (fig. 10).

The bundles which supply the outer fleshy layer of the integument
branch several times before they reach the level of lower limit of the
stony layer, but from this point they extend to the micropyle with no
branching at all (fig. 7). The number of these bundles in vigorous
ovules varies from 10 to 17, with 14 as the most frequent number;
in abortive ovules 12 and 1 3 are the most frequent numbers. In
very cone there are some abortive ovules, and it may be that an

340 BOTANICAL GAZETTE [NOVEMBER

inferior vascular supply has something to do with their failure to
develop.

The bundles passing to the inner fleshy layer begin to branch a
little higher up than do those of the outer layer. There is some
branching in the basal papilla; after passing out to the inner fleshy
layer there is repeated forking, as shown in fig. 8, so that a transverse
section taken at the level of the archegonia shows 40 to 60 bundles.
After passing from the stony layer, these bundles run in the outer
part of the inner fleshy layer of the integument and extend up to the
free portion of the nucellus. Occasionally a bundle continues in
the inner fleshy layer beyond the beginning of the free portion of the
nucellus, but in no case was a bundle found entering the nucellus
itself. Occasionally a small bundle passes through the middle of the
basal papilla, through the thin portion of the stony layer, and into the
tissue at the base of the endosperm. The development of the bundles
and the significance of the various details of the vascular system have
not been attempted.

IV. THE FEMALE GAMETOPHYTE.

Stages showing the origin and early development of the female
gametophyte were not secured. Since fruiting plants are compara-
tively rare, and since they cannot be distinguished from vegetative
specimens until the cones are well started in their development, the
earliest stages could be obtained only by a vandal-like mutilation of
plants large enough to bear cones. The youngest ovules, collected
early in November, were about 8™™ in length, and showed the arche-
gonium initials. The gametophyte had become cellular throughout,
no free nuclear portion remaining at the center. Only one small cone
had ovules as young as this, the ovules in the cones of this date meas-
uring about 1°™ in length and showing the central cell of the arche-
gonium.

During November, December, and January the pressure exerted
by the young gametophytes is remarkable. At a slight cut into the
tough layer which is to become stony, a distinct snap can be heard,
the cut gapes open, and the gametophyte protrudes. Later, when its
cell walls have become firmer, the gametophyte retains its form when
cuts are made into the stony layer. When an ovule in which the

1906] CHAMBERLAIN—OVULE OF DIOON 341

gametophyte is still spherical is cut through the middle, the gameto-
phyte, as seen with the naked eye, has a beautiful, radiating appear-
ance, looking somewhat like a transverse section of a twig with very
fine and numerous medullary rays. Until late in December the endo-
sperm is almost transparent, so that the young archegonia are easily
seen and counted, even when the endosperm is removed entire. Ordi-
nary newspaper print can be read through a section of endosperm
4™™ in thickness. At this stage the endosperm tastes sweet on account
of the abundant sugar, but as soon as starch begins to form it takes
on a translucent white color, and as the starch becomes abundant an
opaque white. Even before the starch begins to appear, the endo-
sperm commences to elongate, and in February has reached a length
of 15™™ and a breadth of 1o™™. In April, when the endosperm has
reached its full size, it is about 25™™ in length and 17™™ in breadth.

Early in December there not only is no archegonial chamber, but
the top of the gametophyte containing the young archegonia is even
elevated (fig. 15). In February the tissue at the rim of the elevation
begins to grow rapidly, while the growth of the elevation itself is
checked; consequently, the elevation soon becomes the bottom of the
archegonial chamber ( jig. 16). At the time of fertilization the arche-
gonial chamber has reached a depth of 1 to 1.5™™ (jig. 17).

The megaspore membrane—Early in November, while the endo-
sperm is still spherical, the megaspore membrane is well developed.
In fresh material one might easily mistake the endosperm jacket for
the membrane, but the jacket is much coarser and can be stripped off
entire with forceps. The membrane is comparatively delicate, but
pieces several millimeters in length may be stripped off with forceps.
When the nucellus is removed, the portion of the membrane covering
the archegonia usually adheres to the nucellus rather than to the endo-
sperm. The membrane is thinner at the apex and base of the endo-
sperm than on the sides. In young ovules, with the endosperm still
spherical, the greatest thickness of the membrane which was measured
Was 3m at the apex, 3.1m at the base, and 4.5 at the sides. The
average at this stage is about 3 at the base and apex, and 4.14 at
the sides. In ovules whose endosperm has reached a length of 1.5°™,
but in which the archegonial chamber has not yet begun to form, the
membrane is rather uniformly about 5 in thickness. In germinating

442 BOTANICAL GAZETTE [NOVEMBER

seeds in which the embryo is beginning to break the stony layer, the
membrane reaches a thickness of 9-10, but the membrane is homo-
geneous, there being no differentiation into layers as in earlier stages.

The membrane clearly consists of two layers, which may be called
the endospore and exospore (jigs. 12,18). The outer layer in young
ovules is three or four times as thick as the inner, but in older ovules
the difference is not so great. The inner layer seems perfectly homo-
geneous under the highest magnification. The outer layer, under
moderate magnification, looks somewhat like the dense outer layer
of the megaspore membrane of Marsilea; but with a Bausch and
Lomb ;}, immersion and Zeiss oc. 12 the structure appears to be com-
paratively loose (fig. 18). The entire outer layer consists of club-
shaped bodies. In other gymnosperms similar bodies have been
described as prismatic, but in Dioon they really consist of a globular
or ovoidal outer portion connected with the inner layer of the mem-
brane by a stalk. In surface view these bodies are seen to be regu-
larly arranged and to be quite uniform in size, the diameter of the
head in November ovules being about 0.85 #, and in the following
February about 1. As will be seen from the figure, the stalks form
a comparatively open structure between the heads and the endospore.
This open region appears as a nearly black line when seen in sections
more than 1 or 2» in thickness, so that there seem to be three layers,
the extra layer being only an optical effect caused by the stalk region.

The membrane covers the entire female gametophyte, but after
the pollen chamber breaks through the base of the nucellus the portion
of the membrane covering the archegonial chamber is ruptured, so
that the two chambers form one continuous cavity. This cavity is
moist, but is not filled with a liquid. Only a few chemical tests were
made and the results agreed with those of Tomson (21), who found
the outer layer of the membrane to be suberized, while the inner layer
iss uberized only where it is in contact with the outer layer. The inner
portion of the inner layer, next the gametophyte, consists of cellulose.
That the megaspore membrane is a vestige surviving from an ancestry
which shed the megaspores seems too probable to be questioned.
If it could be assumed that the ancestors of all the living cycads had
megaspore membranes of equal thickness, and that in the surviving
forms the membrane has been reduced uniformly in all genera, then

1906] CHAMBERLAIN—OVULE OF DIOON 343

the living genus with the thinnest membrane could be regarded as the
farthest removed from its ancestry, and the genus with the thickest
membrane would represent most nearly the ancestral condition. In
spite of the uncertainty of such suppositions, it seems reasonable to
regard a thick membrane as a primitive character, and while not
conclusive evidence in itself, it deserves to be considered with other
features in any discussion of the phylogeny of the cycads.

It would be interesting to know the thickness of the megaspore
membranes of the other cycads at various stages in the life history.
THomson (21) found that in Cycas revoluta the membrane is slightly
more than 5 in thickness at the stage when cell division is beginning
in the endosperm. At a somewhat later stage the same writer found
the membrane of Stangeria paradoxa to be 4.5 » in thickness, and the
same thickness is given for the membrane of mature seeds of Zamia
integrijolia; while in Ceratozamia longifolia the membrane is 4.54
in thickness at a stage when the archegonia have been formed. In
Dioon imbricatum,? before the appearance of archegonia, the thick-
ness was 3.8. Ihave measured the membrane in the above genera,
except Stangeria, and find only such slight variations from THoMsoN’s
figures as may be accounted for by slight differences in stages of
development. The extreme thickness of the membrane in the germ-
inating seed of Dioon so much exceeds any of THoMSON’s measure-
ments that it would be interesting to know whether the membranes
of other gymnosperms increase so much in thickness when the seeds
germinate. The megaspore membrane of Dioon is as thick as that
of any cycad, and consequently, so far as this one character is con-
cerned, Dioon is as primitive as any member of the group.

Development of the endosperm.—Early in November, about two
months after pollination, the endosperm has become cellular through-
out. If one might hazard a guess at previous stages, the November
Condition looks as if the free nuclear condition had been succeeded
by the formation of very large cells which had been divided repeatedly.
At a stage when the archegonium initial is first distinguishable, the
peripheral cells of the endosperm about half way between the arche-
gonial and chalazal regions present the appearance shown in fig. 19.

is form is described by Mr1QueEt, in his Prodromus Systematis asl
ets under Dioon edule Lindl., as 8 imbricatum, and is based upon leaf characters

344 BOTANICAL GAZETTE [NOVEMBER

Except at its apex, the structure of the gametophyte is like that shown
in this figure, a single layer of small peripheral cells being succeeded
by layers of larger and larger cells. At the apex, where the arche-
gonial initials are appearing, the single layer of small cells broadens
rapidly into a lenticular group, from 7-10 cells in thickness. This
group consists of about 200 cells, which are considerably smaller than
those of the peripheral layer, as may be seen by comparing jigs. 19
and 23, which are drawn to the same scale. The archegonium initials
may be seen at the periphery of this group. At this stage, the cells
of the gametophyte contain no starch or other food stuffs, the only
visible contents being the nucleus, a scanty amount of cytoplasm, and
the transparent cell sap.

Three weeks later, when the endosperm has reached a length
of 15™, the cell contents seem to be just the same as before, no
accumulation of foodstuffs being visible. Cell division has progressed
rapidly, so that the row of four cells shown in fig. 19, a, is now repre-
sented by the two rows (sixteen cells) of fig. 20, a. Sections of the
endosperm 4™™ thick, fixed in Flemming’s solution early in December,
appear somewhat darker in the region of the archegonia. In the
chalazal region there is also a slightly darker color. Microtome sec-
tions show that the color is due in part to occasional grains of starch,
but more particularly to small globules, probably oil, which stain
black with osmic acid. The fact that the cells are considerably
smaller in the archegonial region also makes the endosperm appeat
denser at this place. In the ripe seed the gametophyte shows con- -
siderable differentiation (fig. 21). The cells of the peripheral layer
are small, rich in protoplasm, and contain numerous very minute
starch grains. This layer contrasts sharply with the next, the cells of
which are much larger and contain larger starch grains. This second
layer is in turn fairly well marked off from the rest of the gametophyte,
which consists of still larger cells densely packed with large starch
grains. Numerous isolated cells containing tannin form a broad zone
midway. between the center and periphery of the endosperm. The
tannin is much more abundant in the upper part of the gametophyte.

Development oj archegonia—Probably all of the superficial cells
of the group at the apex of the endosperm are potentially arche-
gonium initials. The number of archegonia varies from none at

1906] CHAMBERLAIN—OVULE OF DIOON 345

all to ten. Several ovules at the period of fertilization showed no
archegonial chamber and no trace of archegonia. Ten archegonia
were observed in only a single instance, which was also exceptional in
having two archegonial chambers. A single archegonium with a small
archegonial chamber was observed in a few cases. Usually there are
three, four, or five archegonia, with four as the most frequent number.
An archegonium initial, which can be seen- early in November,
becomes distinguishable by its slightly greater size (figs. 22, 23).
The division into a neck cell and central cell takes place early, prob-
ably in November (fig. 24). The neck cell divides almost immediately,
forming the two-celled neck which is a constant feature in all cycads
yet investigated. All December ovules not only showed the neck,
but the neck had already divided into its two characteristic cells
(jig. 25).

The central cell enlarges very rapidly, its scanty protoplasm form-
ing a delicate layer pressed against the wall by the single large sap
vacuole (jigs. 24, 25). Even at the stage shown in fig. 24, the cells
bordering upon the central cell are rather regularly arranged, and in
fig. 25 there seems to be a definite jacket. While this layer functions
more or less in the nutrition of the central cell, the real archegonial
jacket with its characteristic cell contents is formed later by both
periclinal and anticlinal divisions in the jacket-like layer of fig. 25.
The differentiation of the jacket is not so rapid at the apex of the cen-
tral cell as at the sides and base. As soon as the jacket begins to be dif-
ferentiated from the neighboring cells, the cytoplasm of the central cell
increases rapidly, and soon the space which had been occupied by the
single large vacuole is filled. The rapidly increasing cytoplasm shows
a beautiful foam structure (fig.26). At this stage there is no reticulum
or even any fibers. - The vacuoles of the central cell are much smaller
at the apex and at its periphery than nearer the center. The walls of
these vacuoles are themselves vacuoles, and there is a perfect grada-
tion, so far as size and appearance is concerned, from the large vacuole
near the center to the smallest vacuoles of the thin plates of cytoplasm
Which form the walls of the large vacuoles. Some of the walls of
the larger vacuoles are shown in surface view in fig. 26, though
Most of the walls show only the edges, as in case of cell walls. The
smallest of the vacuoles are small enough to come within BUTSCHLI’s

346 BOTANICAL GAZETTE [NOVEMBER

limit for the size of meshes of genuine protoplasmic structure. The
central cell of the archegonium is formed early in November, a little
more than two months after pollination. The mitotic division which
gives rise to the ventral canal nucleus and the nucleus of the egg
takes place about the middle of the following May, so that the growth
of the central cell and its nucleus extends over a period of six months.
Throughout this entire period the growth is uniform, there being no
cessation or 1 as would be the case in a colder climate.

The nucleus of the archegonium initial begins to enlarge very
early, and is noticeably larger than the nuclei of the surrounding cells
as soon as the initial itself becomes distinguishable (jig. 22); but
while the growth of the nucleus continues steadily, it does not keep
pace with the more rapid growth of the central cell. In March,
after five months growth, the diameter of the nucleus has increased
from 1o# to 7o#. The nucleolus, which at first was inconspicuous,
has become prominent, and the chromatin granules are evenly dis-
tributed throughout the nucleus. At this time several large nucleolus-
like bodies appear in the cytoplasm near the nucleus (jigs. 27, 29).
These bodies strongly resemble those which are found between the
blepharoplast and nucleus in the body cell of Gingko, as described by
HrrasE (9). At first they are solid and perfectly homogeneous; but
as the nucleus of the central cell begins to divide, they become vacuo-
late (jig. 29), and before the mitosis has reached the metaphase they
have broken up into innumerable small globules and granules (jig. 30):
These bodies stain black with iron haematoxylin, and with the
safranin gentian-violet combination they usually take the violet
even when nucleoli are staining red with the safranin. Their exact
nature and function was not determined, but they do not seem to
differ, except in size, from the globules of nutritive material which are
soon afterward brought into all parts of the egg by the haustoria.

The ventral canal nucleus —While the growth of the nucleus of the
central cell extends over a period of more than six months, its division,
when once begun, is extremely rapid. The only figures found were
in material sent from Xalapa on April 1, 1905, and fixed at Chicago
on April 13 and 17. No figures were found in any of the numerous
collections fixed in March. Some ovules fixed later than April 17,
and even as late as May 13, showed the nucleus of the central cell

1906] CHAMBERLAIN—OVULE OF DIOON 347

still undivided; but such ovules were from cones picked about the
middle of March, and the ovules finally decayed without any division
of this nucleus. The top of the typical archegonium in such material
is shown in fig. 28, which is from a cone picked March 18, the material
being fixed May 13, nearly two months later. The two neck cells
are in perfect condition, but the central cell has begun to degenerate.

In normal material the spirem is broad but very tenuous in consis-
tency. In the only cases noted it had evidently suffered from reagents
(fig. 29). The shortening, condensation, and segmentation of the
spirem were not observed, the next available stage being shown in
fig. 30, where the. segmentation into chromosomes has taken place.
_ The splitting of the chromosome in the equatorial plate is shown in
fig. 31. In this preparation the number of chromosomes was deter-
mined with reasonable though not absolute certainty to be twelve.
In a late anaphase the chromosomes, while still retaining the U-shape,
are becoming irregularly moniliform, looking as if they might break
up into small pieces (fig. 32). Only a few stages in the formation of
the spindle were observed. The first indication of it is a granular and
fibrillar appearance which is more marked at the lower pole of the
nucleus (fig. 29). There are no centrosomes, and in fig. 30 the poles
are rather blunt. Fibers like the spindle fibers are abundant in the
cytoplasm of the papillate projection in which the figure lies. In
fig. 31 the spindle is more sharply bipolar, and long mantle fibers are
more conspicuous, although many of the spindle fibers are still con-
tinuous from pole to pole. Fig. 32 shows no trace of the granules
which mark the beginning of a cell plate, and later stages make it
certain that no wall is formed between the daughter nuclei. The
ventral canal nucleus remains free in the cytoplasm of the egg, as
shown in jigs. 33-35.

A ventral canal cell in cycads was first described by STRASBURGER
(18) in 1876 for Cycas sphaerica. The next year WARMING (23)
described one in Ceratozamia robusta, but soon concluded that he had
been mistaken. Treus (22) in 1884 failed to find any ventral canal
cell in Cycas circinalis, and from that time it was generally believed that
the cycads have no ventral cell. However, in 1898 IkENo (10) made an
unmistakable demonstration of the critical mitosis in Cycas revoluta,
At that time no ventral canal nucleus not separated from the egg

348 BOTANICAL GAZETTE [NOVEMBER

nucleus by a wall had yet been observed, and he merely followed
current terminology. The term ventral canal nucleus was introduced
by CoKER (3) in 1902 to describe the condition in Podocarpus. IKENO’s
figures show that no wall is formed between the ventral canal nucleus
and that of the egg. WEBBER (24) soon afterward reported that in
Zamia ‘“‘a small cell is cut off at the apex of the archegonium,” but
here too the language is unfortunate, for no cell is cut off, and the
ventral canal nucleus remains in the general cytoplasm of the egg, as
shown by Courter and CHAMBERLAIN (5). I have recently made
preparations of Encephalartos showing the same condition. It is
probable that no ventral canal cell is cut off in any of the cycads,
there being merely a nuclear division.

It cannot be doubted that this represents an advanced stage in the
reduction of the archegonium. It offers no exception to the method
by which the row of neck canal cells of the bryophytes and pterido-
phytes has been reduced. In these groups binucleate neck canal
cells are frequent. This means that the formation of a cell wall has
failed to follow the nuclear division. The next stage in reduction
would be the suppression of the mitosis, and thus a diminution in
the number of neck canal cells. In this way the neck canal cells grad-
ually become reduced in number, some pteridophytes showing only a
single one. In gymnosperms there is no neck canal cell at all, and
the ventral canal cell is being eliminated by the same process. In
some genera, like Pinus, the ventral canal cell is separated from the egg
by a wall. In other genera the nuclear division takes place, some-
times with a series of granules on the spindle indicating a rudimentary
cell plate, but no wall is formed. In Torreya it seems likely that even
the ventral canal nucleus is suppressed. The absence of a yentral
canal nucleus has been reported for several genera, but the evidence
is not conclusive. Dioon, Zamia, Cycas, and Encephalartos still
preserve the mitosis, although the wall is no longer formed. In this
particular, although the oldest of living gymnosperms, the cy cads
do not show as primitive a condition as do Pinus and some other
Coniferales.

After the mitosis described above, the ventral canal nucleus forms
a membrane and may enlarge slightly, but it soon disorganizes, So that
at the time of fertilization a scarcely recognizable vestige remains.

1906] CHAMBERLAIN—OVULE OF DIOON 349

Typical views are shown in figs. 33, 3 3a, and 34. Occasionally there
is considerable enlargement (fig. 35), as is often the case in Pinus. I
have a preparation of Encephalartos which not only shows a reorgani-
zation and enlargement of the ventral canal nucleus, but the nucleus
has moyed down from the papillate projection toward the egg, sug-
gesting the possibility of fertilization of the egg by the ventral canal
nucleus. In StRASBURGER’s account (33) of fertilization in Picea
vulgaris and in CouLrer’s account (3) in Pinus Laricio, describing
fusing nuclei of equal size, a large ventral canal nucleus was doubtless
mistaken for a male nucleus, but that these were actual cases of
fertilization of the egg by its own ventral canal nucleus there can
be but little doubt.

The egg and archegonial jacket—The egg of Dioon is the largest
yet known in plants. It is seldom less than 4™™ in length and often
Teaches a length of 5™™; the largest egg measured was 6™™ in length.
The actual size, just after the formation of the ventral canal nucleus,
is shown in fig. r7a. The egg at the right in this figure is shown again
in fig. 17, which is magnified six diameters so as to show the com-
parative size of the papilla, ventral canal nucleus, and egg nucleus.
Before fertilization the egg nucleus becomes much larger and more
deeply placed than is represented in this figure. In fig. 15, which
shows the actual size of the central cell before the beginning of the
archegonial chamber, and in fig. 16, showing the beginning of the
archegonial chamber, the nucleus of the central cell is too small to
be represented even by a single dot.

The nutrition of the egg is practically the nutrition of the central
cell, for it reaches its mature character before the mitosis which
separates the ventral canal nucleus from that of the egg. Goro-
SCHANKIN (8) in 1883 described a continuity of protoplasm between
the jacket cells and egg of Ceratozamia. He believed that strands
Piet protoplasm pass through sieve plates in the pits of the jacket.
TKENo (10) in 1898 made a more detailed study of the growth of the
€8g in Cycas. He also described protoplasmic continuity between
the jacket cells and the egg, and a passage of proteid materials from
the jacket into the egg. Miss Isapet SmirH (14), who studied the
hutrition of the egg in Zamia floridana, found no connecting strands
of protoplasm, but found projections, which she called haustoria,

350 BOTANICAL GAZETTE [NOVEMBER

extending from the egg into the jacket cells. In Dioon there are
haustoria similar to those of Zamia. An examination of Cerato-
zamia, Cycas, and Encephalartos showed that they also have haus-
toria like those of Zamia and Dioon. The origin, development, and
function of the haustoria, together with changes in the jacket cells
of the surrounding tissue, would be a long problem, involving chem-
istry as well as morphology.

During the early stages of its growth (figs. 24-26) the central cell
receives food material from the surrounding cells by the usual method
of transferring substances from one cell to another. Up to the stage
shown in fig. 25, the wall of the central cell is very thin, with no visible 3
pits; but later the inner surface of the wall undergoes an extensive
secondary thickening, interrupted only by the large pits which are
such a conspicuous feature of cycad eggs. After the haustoria have
become fully developed, their cytoplasm is in direct contact with that
of the jacket cells, so that substances may pass from the jacket cells
into the haustoria as readily as from one part of the jacket cell to
another. A paper was received from Drs. Stopes and Fuyu (17) just
as this account is going to press, describing sieve plates as found by
GOROSCHANKIN (8). Their figures are evidently drawn from young
material, in which the haustoria have not reached their full develop-
ment. ‘That there is protoplasmic continuity here, as elsewhere, we
do not doubt; but if the pit-closing membrane persists in stages like
those shown in our figs. 37-41, it has escaped our observation. The
haustoria project far into the cells of the jacket, and the mere thrust
may have ruptured the membrane. At the stage shown in fig. 30;
it is possible that the membrane may still be present; but in stages
like figs. 37-41 we could not find any membrane, even after a reexam-
ination of our preparations. Consequently, we see no reason for
modifying the following account, which was written before the paper
by Drs. Stopes and Fuyjm was received.

The general method by which nutritive materials reach the egg
is easily understood. The tissue of the female gametophyte is filled
with starch and other food materials, which in a changed form pass
into the archegonial jacket and thence into the egg. The cells of ihe
archegonial jacket at certain times contain numerous starch grains,
much smaller than those in the surrounding endosperm cells, but

1906] CHAMBERLAIN—OVULE OF DIOON 351

the starch is soon dissolved. The change from starch to a soluble -
form doubtless takes place repeatedly, because the starch at various
Stages in the development of the archegonium is sometimes present
"and sometimes absent. The protoplasm of the jacket cells is abun-
dant and their nuclei are much larger than those of the surrounding
tissue. The changes taking place within these cells and nuclei
resemble those which occur in glandular cells, there being a period
of accumulation, followed by discharge, and then exhaustion, after
which the processes are repeated. Glandular activity begins in
December, as soon as the archegonial jacket becomes distinguishable.
At this time the protoplasm of the central cell consists of a thin periph-
eral layer, and still thinner lamellae which divide the interior into
vacuoles of various sizes, those near the center being the largest
(fig. 36). The activity increases gradually up to the time of fertili-
zation, about the first of May, and then diminishes. At the close of
the period of free nuclear division in the proembryo, the jacket is not
very vigorous, but there is still some activity. Toward the close of the
intrasporal development of the proembryo, the jacket cells become
weak in contents and begin to break down; and after the embryo has
broken through the base of the egg and advanced 4 or 5™™ into the
endosperm, the jacket is scarcely recognizable. During the period
of repose or exhaustion (jig. 36) the protoplasm of the jacket cells is
finely vacuolated. The nucleus has a somewhat homogeneous,
finely granular structure, in which the chromatin is not conspicuous,
although it can be seen that most of it is in the half of the nucleus
nearest the egg. The protoplasm of the haustoria is evenly granular.
As activity begins (fig. 37), the protoplasm of the jacket cells
becomes more coarsely vacuolated and food materials of various
shapes and sizes appear within it. The nucleus is particularly active.
The nucleolus becomes saturated with a substance which stains black
with iron haematoxylin, and the chromatin first becomes conspicuous
and then obscured by a substance which also stains black and may
© the same as that in the nucleolus. Material passes from the
nucleus into the cytoplasm and from the cytoplasm into the haus-
‘orla. Once within the haustoria, the food materials are already
within the egg. In passing from the haustoria to the deeper portions
of the egg, the materials break up into smaller and smaller granules

352 BOTANICAL GAZETTE [NOVEMBER

and globules, so that the periphery of the egg always contains the
most conspicuous contribution from the jacket. The food materials
never take the form of “proteid vacuoles” as in Pinus, and are never
in danger of being mistaken for nuclear structures. The appear-
ance of the jacket and the periphery after a discharge is almost com-
pleted is shown in jig. 38.

The three preceding illustrations (figs. 36-38) show the condi-
tions in young eggs while the protoplasm is still quite scanty, most
of the space being occupied by large vacuoles. Later stages, after
the egg has become filled with protoplasm and the large vacuoles
have disappeared, are shown in figs. 39-41. In fig. 39 the ends of
the haustoria are covered by a frothy substance, and in fig. 4o it is
seen that this substance is passing into the egg. A large vacuole
marks the place which has just before been occupied by frothy sub-
stance. The nucleus, as is often the case, is concave on the side
next the haustoria. A later stage is shown in fig. 41, which repre-
sents various kinds of food materials within the egg. Globules and
droplets of various forms are most abundant, but crystalloids are not
infrequent. The crystalloids are cubical or may approach the
spherical form, but are never fusiform like those so characteristic
of the egg of Zamia. Starch is sometimes present but generally
absent. = }

The structure of the protoplasm of the egg undergoes great changes,
especially during the last two months of its development. In Decem-
ber the protoplasm, containing one large vacuole, forms only a thin
layer pressed against the periphery of the central cell (jig. 25)- In
March the protoplasm has increased greatly in quantity and numerous
vacuoles have appeared (figs. 36-38). In these figures, and even in
considerably later stages, the lines represent the edges of lamellae,
and the appearance is a strong argument in favor of the foam or
Waben theory of the structure of protoplasm. In later stages,
however, the foam structure disappears, and the protoplasm seems
to be almost entirely in the form of fibrillae (fig. 41). The change -
seems due in great part to the breaking down of lamellae, thus leaving
fibrillae at the junctions.

Why the nucleus of the central cell remains at the apex for s0
many months, and why after the mitosis the egg nucleus moves down

1906] CHAMBERLAIN—OVULE OF DIOON 353

while the ventral canal nucleus remains at the apex, are questions
still unanswered. A moment’s reflection will convince any one that
neither temperature, light, nor gravity has any appreciable influence.
The path by which nutrition reaches the egg may be an important
factor, for the extensive vascular system of the ovule terminates near
the top of the endosperm. On the other hand, the same position of the
nucleus is found in gymnosperms whose ovules have scarcely any
vascular tissue at all. Later, during the formation of the proembryo,
the polarity is reversed, the nuclear activity being most vigorous at
the base of the egg. At this time it is evident that nearly all the
nutrition is coming from the endosperm at the base of the egg. Asa
working hypothesis it may be suggested that the early position of
the nucleus at the apex, and also the reversal of the polarity, are due
to chemotaxis, the source of nutrition being the controling factor.

The egg nucleus.—The egg nucleus of Dioon is the largest which
has yet been found in plants. Its usual diameter is about 500 p,
but nuclei sometimes reach a diameter of 600 #. Not infrequently the
nucleus is elongated, and in such cases its bulk is likely to be greater
than that of the usual spherical nucleus. One nucleus measured 1475 #
by 3804. In spite of the immense size of this nucleus, its structures
could not be interpreted. Its chromatin content is shown at the lower
end of the spindle in fig. 32. Stages immediately following this were
not secured, and in stages like jigs. 34 and 35 the chromatin can no
longer be identified. From this time to the entrance of the sperm
into the egg, the internal structure of the nucleus is shown in figs.
42-44, which represent details as they appear under a magnification
of 1300 diameters. The entire nucleus, drawn to this scale, would
be more than 6™ in diameter! In all parts of the nucleus is found a
delicate network of varying thickness, and upon it or imbedded in it
are granules and globules of various sizes. The smallest granules,
which are almost always associated with the network or clinging to the
Surface of larger globules, stain with gentian-violet. Most of the
larger globules stain with safranin, so that the general tone of the
network is red; but some stain with the gentian-violet and in others
the two stains blend. There are always a few which do not stain at all.
In most preparations the network stains very faintly or not at all.
The nucleoli, which are large and vacuolated, can usually be distin-

354 BOTANICAL GAZETTE [NOVEMBER

guished from the globules represented in jigs. 42-44. If any of these
granules represent the chromatin, the individuality of the chromo-
somes would appear to be hopelessly lost. No satisfactory study of
the living nucleus was made. A nucleolus is visible in living material,
but otherwise the contents seem nearly homogeneous. There are few
globules and the network could not be identified. It is possible that
most of the globules and the network are coagulation artifacts due to
fixing. :

The development of the egg nucleus seems to be essentially the same
in all gymnosperms. Among the investigators who have studied this
nucleus in various gymnosperms may be mentioned STRASBURGER (19,
20), IkENo (10), BLACKMAN (1), CHAMBERLAIN (2), FERGUSON (7),
and LAND (11). BLACKMAN, CHAMBERLAIN, and FERGUSON attempted
to follow the behavior of the chromatin, but the accounts are inade-
quate, there being stages in which all fail to identify convincingly the
chromatin. Miss Fercuson’s beautiful figures of Pinus show the
familiar structures with great accuracy, but just what structures are
chromatin is not clear. My own series of Pinus is less complete, and
those of other writers are still more incomplete. In Dioon it is
evident that this nucleus behaves much as in Pinus. The solution
of the problem is not easily attained in cycads on account of the
inaccessibility of material and the difficult sectioning. In Pinus,
with its abundant material and easy technique, a close series in the
development of the nucleus and in the formation of the spirem at the
time of fertilization would probably lead to an understanding of the
egg nucleus of the whole group.

SUMMARY.

1. Dioon occurs in abundance at Chavarrillo, Mexico.

2. It is probable that plants often reach an age of more than one
thousand years.

3. The ovulate strobilus is more like the loose ovulate strobilus
of Cycas than the compact ovulate strobili of the other genera.

4. The megasporophylls are more leaf-like than those of any
other genus of cycads except Cycas.

5. The integument consists of three layers: an outer and an
inner fleshy layer, with a stony layer between them. The integu-

1906] CHAMBERLAIN—OVULE OF DIOON 355

ment is probably double in nature, the outer fleshy layer representing
the outer integument.

6. Only a small portion of the nucellus is free from the integument.

7. One vascular bundle passes from the sporophyll toward each
ovule. Before entering the ovule the bundle forks, one branch form-
ing the continuously branching system of the inner fleshy layer of the
integument, and the other forming the slightly branched system of
the outer fleshy layer.

. The megaspore membrane varies in thickness from 3-4.5 # in
young ovules to g—10 # in mature seeds.

9. The number of archegonia varies from one to ten, with four
and five as the most frequent numbers. The archegonium initial
appears in October; the division into neck and central cell takes
place almost immediately after; the mitosis which forms the ventral
canal nucleus and egg nucleus takes place during the next May.

10. The central cell and egg during earlier stages receive food
substances by the ordinary method of nutrition, but later receive
food material through haustorial projections from the egg which are
in direct contact with the cytoplasm of the jacket cells.

11. There are twelve chromosomes, in the egg nucleus, which is
the largest one yet known in plants.

THE UNIVERSITY OF CHICAGO.

LITERATURE CITED.

_ 1. Biacxman, V. H., On the cytological features of fertilization and related
features in eine sylvestris L. Phil. Trans. Roy. Soc. London B. 190:
395-426. pls. 12-14. 1808.

- CHAMBERLAIN, C. J., Oogenesis in Pinus Laricip. Bot. GAzeTTE 27:
268-280. pls. 4-6. 1899.

- Coxer, W. C., Notes on the gametophytes and embryo of Podocarpus.

Bor. Gazerre 33:89-107. pls. 5-8. 1902.
Couter, J. M., Notes on the fertilization and embryogeny of Conifers.
Bor. Gacerts 23:40-43. pl. 6. 1897.

- Courter, J. M., and CHAMBERLAIN, C. J., The embryogeny of Zamia.
Bor. Gazerre 35:184-194. pls. 6-8. 1903.

- Coutrer, J. M.; and Lanp, W. J. G., The genie and embryo of
Torreya taxifolia. Bor. GAZETTE 39:161-178. pls. I-3. 1905.

; apa eee Marearet C., Contributions to the cae of the life history

of Pinus. Proc. Wash. Acad. Sci. 6:1-202. pls. 2-24. 1904.

N

w

>

uw

an

~I

356 BOTANICAL GAZETTE [NOVEMBER

8. GOROSCHANKIN, J., Zur Kenntniss d. Corpuscula bei den Gymnospermen.
Bot. Zeit. 41:825-831. pl. 70, 1883.

g. Hrrase, S., Etudes sur la fécondation et 1 ’embryogénie du Ginkgo biloba.
Jour. dan Coll. Sci. Tokyo 8: 307-322. pls. 31-32. 1895.

10. IkENO, S., Untersuchungen iiber die Entwickelung der Geschlectsorgane
und der Vorgang der Befruchtung bei Cycas reyoluta. Jahrb. Wiss. Bot
32:557-602. pls. 8-10. 1898

11. Lanp, W. J. G., Spermatogenesis and oogenesis in Ephedra trifurca. Bot
GAZETTE 38:1-18. pls. 1-5. 1904.

. Lanc, W.H., Studies in the development and morphology of cycadean spo-
rangia. II. The ovule of Stangeria paradoxa. Annals of Botany 14:
281-306. pls. 17-18. 1900.

13. Outver, F. W., and Scorr, D. H., On the structure of the paleozoic seed,

Lagenostoma Lomaxi. Phil. Trans. Roy. Soc. London B. 197:193-247:

al
N

pls. 4-10. 1904.
14. Smita, IsaBet, The nutrition of the egg in Zamia. Bot. GAZETTE 37:
6- 3-

346-352. 190

15. Stopes, M. C., Beitraige zur oe toes der Fortpflanzungsorgane der Cyca-
deen. Flora 93: 435-482. 1904.

, On the double i of the cycadean integument. Annals of
Boiany 19:561-566. Ig05.

17. Stopes, M. C., and Fuym, K., The nutritive relations of the surrounding
tissues of the archegonia in gymnosperms. Beih. Bot. Centralbl. 20:
1-24. pl. 1. 1906,

18. StRasBuRGER, E., Ueber Zellbildung und sanegice Leipzig. 1876.

‘Befruchtung und Zelltheilung. Jena. 18

den i Cymineepennels Hist. Beitr. 4:1~158. pls. 1-3. 1

21. THomson, R. B., The megaspore membrane of the el Univ.
Toronto Studies, Biol. Ser. no. 4. 85-145. pls. I-5. 1905.

22. TreEuB, M., Recherches sur les Cycadées. 3. Embryogénie du Cycas cir-
cinalis. ‘Aun, Jard. Buitenzorg 4:1-11. pls. 1-3. 1884.

23. Warminc, E., Recherches et remarques sur les Cycadées. Oversigter
KD: Videusk: Site: Fork: 1879.

24. WeBBER, H. J., Notes on the fecundation of Zamia and the pollen tube
apparatus of Gingko. Bor. GAZETTE 24:225-235. pl. 10. 1897-

EXPLANATION OF PLATES XITI-XV.

(Fics. 1-9 are text cuts.)

Fic. ro. Longitudinal section of ovule: a, abscission layer; ¢, rea
i, inner fleshy layer of integument; ib, bundle of inner vascular m;, ™,
micropyle; #, free portion of nucellus; 0, outer fleshy layer of sation ?
bundle of outer fleshy layer; , basal papilla; s, stony layer of integument. x2.

PLATE XIf1

VICAL GAZETTE, XL

3 (Z)y
As wa, Za =

thos
49S. I Chumbertain det

CHAMBERLAIN on DIOON

L GAZETTE, XLII

Chambertain

CHAMBERLAIN on DIOON

EL GAZETTE, XL

"Rambertaun ¢:

CHAMBERLALN on IO

PLATE XV

1906] CHAMBERLAIN—OVULE OF DIOON 357

_ Fic. 11. Longitudinal section through integument and adnate portion of
nucellus: e, epidermis; el, longitudinally elongated cells of stony layer; et,
transversely elongated cells of stony layer; ej, endosperm jacket; g, endosperm;
4, isodiametric cells of stony layer; 7b, bundle of inner vascular system; 7/, inner
fleshy layer of integument; i, inner layer of longitudinally elongated cells ss
stony layer; », adnate portion of nucellus; 0d, bundle of outer vascular iene
oj, outer fleshy layer of integument; ~, parenchyma cells of outer fleshy layer;
5, stony layer; ¢, cells containing tannin. x2 -

Fic. 12, Section showing endosperm (e), megaspore membrane (m), an
endosperm jacket (ej). X 350.

Fic. 13. Cell of endosperm jacket showing one normal nucleus and a free
spirem of another nucleus. > 350. es ae

Fic. 14. Longitudinal section through abscission layer; #, cells containing
tannin, X 112. Poe

Fic. 15. Section of archegonia early in December, showing endospe:
somewhat raised over the archegonia. Natural size.

Fic. 16. Section of archegonia showing beginning of archegonial chamber.

Natural size, :

Fic. 17. Section of archegonia just after formation of ventral canal nucleus.

X5.

Fic. 17a. The same, natural size. : .

Fic. 18. Transverse section of megaspore membrane. X900. kk
Fic. 19. Section of lateral endosperm at a period aie SE ke initia
are forming at the apex; 280 cells in entire periphery of section. .

? : : : =
Fic. 20. Similar section at a later stage, 780 cells in periphery; the two row
of cells marked a correspond to the single row a of fig. 19. 88.
; i . K88.
Fic. 21. Peripheral portion of endosperm at period of germination. X
Fics. 22-23. Archegonium initials. X88.
Fic. 24. Archegonium, Dec. 21. X88.
Fic. 25. Archegonium early in January. X88.
Fic. 26. Upper portion of archegonium. X88. oes
Fic. 27. Upper portion of archegonium, March 7. . | os
Fic. 28. Upper portion of archegonium, May 13, over two months after co
was picked. x88. Bee :
Fic. 29. Nucleus of central cell and nucleolus-like bodies in the cytoplasm
X 350. ;
: orm
Fics. 30-32. Stages in the division of the nucleus of the central cell to
the ventral canal nucleus and egg nucleus. X 350.
Fic. 33. Ventral canal nucleus. X 350. 4
e
Fic. 33a. Upper portion of egg, showing ventral canal nucleus and egg
nucleus. x29,
Fic. 34. Ventral canal nucleus and egg nucleus, April. ae
Fic. 35. Neck, ventral canal nucleus, and egg nucleus. X41.

358 BOTANICAL GAZETTE [NOVEMBER

Fic. 36. Portion of jacket cell and egg, showing haustorium, March 9. X8oo.

Fic. 37. Jacket and haustoria, March. X8oo.

Fic. 38. Porton of egg and jacket cell just after a discharge. 800.

Fic. 39. Jacket cell and egg showing accumulation of globules over the
haustoria. 800.

1G. 40. Similar haustorium with the globules passing into it. 800.

Fic. 41. Jacket cells and haustoria when the egg is nearly ready for fertili-
zation. X 800.

Fics. 42-43. Details of structure of the egg.nucleus. 1300.

Fic. 44. Small portion of the egg nucleus showing the very irregular outline
of the nuclear membrane. X 1300

TEMPERATURE AND TOXIC ACTION.
CHARLES BROOKS.
(WITH THIRTY-THREE CHARTS)

THE purpose of these experiments, the results of which are pre-
sented in this paper, was to determine what might be the modifying
effect of temperature on the toxic properties of certain chemicals as
shown by the effect of these substances on germination and growth
in certain fungi. Since chemical processes as well as plant activities
are influenced by temperature, it was thought that additional knowl-
edge in regard to the nature of the physiological action of poisons
might be obtained by comparing their effects at the optimum tem-
perature for germination and growth of the plant with results secured
under otherwise similar conditions, but at temperatures below and
above that which is most favorable for the development of the particu-
lar plant.

So far as the writer has been able to learn, the problem of toxic
action has never been carefully investigated from this standpoint. It
is well known that temperature is an important factor in the pro-
cesses of plant and animal life, and that changes in temperature may
often serve as a stimulus to reproduction, germination, and develop-
ment. It has also been shown that the response of an organism to
certain stimuli may vary with the temperature, and some data have
been reported which indicate that this is true when the stimulus is
of a chemical nature. THreLe (1) found that the maximum tem-
perature for the growth of Penicillium glaucum on grape sugat lies
at 31° C., on glycerin at 36° C., on salts of formic acid at 35° C.
NAGEtt (2) reported that bacteria were killed at 30 or 110° C. accord-
ing to the character of the nutrient medium, but his conclusions seem
to be based upon results obtained from impure cultures. H2EIDER (3)
found that the toxic action of certain chemicals upon the spores of
Bacillus anthracis increases with a rise of temperature. PasTEUR (4)
found that bacteria were more resistant to heat in alkaline than in
acid milk; but Conn (5) and BREFELD (6) observed no such increased
resistance in alkaline solutions, RicHET (7) has reported that with
359] [Botanical Gazette, vol. 42 _

360 BOTANICAL GAZETTE [NOVEMBER

various poisons the toxic dose diminishes in amount with the elevation
of the temperature of the body. MatTHews (8) found that a small
rise in room temperature increased the toxic action of certain salts
upon the eggs of the fish Fundulus heteroclitus, but no data in regard
to the extent of the injury were reported.

Considerable work has been done in recent years on the effect of
toxic agents upon the germination and development of fungi, CLARK
(g) determined the concentration of various chemical solutions neces-
sary to produce injury, inhibition, and death in certain fungi. He
found that a solution of n/4 HNO, killed the spores of Sterigmatocystis

nigra within forty-eight hours, that n/8 to m/16 solutions of the same
acid produced total inhibition of the spores, and that 7/32 gave great
injury to the fungus. Botrytis vulgaris spores were killed by /16,
and the plant was greatly injured by n/32 HNO,. With Penicillium
glaucum, n/4 HNO, killed the spores, 2/8 and n/16 totally inhibited
germination, and /32 gave decided injury. H,SO, gave similar
results, but a concentration of n/2 was required to kill the spores of
Sterigmatocystis and Penicillium. With CuSO,, 2/4 killed the spores
of Sterigmatocystis, 2/8 to n/16 gave total inhibition, and 2/32 to n/64
caused decided injury. Botrytis spores were killed by /16 CuSO,,
inhibited by n/32, and the plant greatly injured by n/64. The
spores of Penicillium were killed by 2” and inhibited by ” to 1/64,
while decided injury resulted from 1/128. DuGGar (10) has reported
upon special factors that influence the germination of fungous spores,
and Miss Fercuson (11) has given some of the conditions for germi-
nation in various basidiomycetous fungi. These recent papers have
only an indirect bearing upon the work that follows, but have been
very useful in the suggestion of methods for the solution of the
problem,

METHODS.

The effect of the various toxic solutions at the different tempera
tures was observed by means of the ordinary Van Tieghem cells.
The manner of constructing and the method of using these have
been fully described by CrarKk (g) and Duccar (10).

These cells were never used a second time without being taken
apart and thoroughly cleaned. In cleaning, the cells were boiled
for twenty or thirty minutes, first in an alkali, then in an acid, and

1906] BROOKS—TEMPERATURE AND TOXIC ACTION 36

finally in distilled water. They were dried from alcohol and made
up in the usual manner. The covers were treated as the cells, except
that in each instance they were heated for a longer time, and that
they were given one or two final boilings in redistilled water. All
flasks, vials, etc., used in these experiments were cleaned with alkali,
acid, and distilled water by boiling, as described for the cells.

As a culture medium several vegetable decoctions were tried. It
was found that the five fungi used in these experiments grew well
upon decoctions made from onions, beets, tomatoes, grapes, pars-
nips, beans, mushrooms, and sugar beets. Several series of experi-
ments were made with tomato decoction as a medium, but it was
found that a sugar beet solution gave less precipitate in the presence
of CuSO, and was in general more satisfactory for the work. In
all the experiments reported in this paper beet decoction was used
as the nutrient medium. In making the infusion 600 grams of beets
were used for every liter of water. At the time of using, the decoc-
tion was diluted, by the addition of the toxic solution and water,
to one-half of its former nutrient value.

The toxic agents used were HNO,, H,SO,, and CuSO,+5H,0.
The chemicals were of the highest quality that could be obtained
and the acid solutions were standardized before using. It is a well-
known fact that strong concentrations of CuSO, precipitate proteids,
In solutions at ordinary temperatures in which both are present, this
precipitation continues for a long time, thus continually changiag
the nature of the liquid. Therefore, as it was necessary to make
experiments at considerable intervals of time, the toxic agent was
hot added to the beet decoction until the time of its use in cultures.
Stock solutions of the chemicals were made in water that had been
carefully redistilled from glass ‘in the presence of an oxidizing agent.

ormal or one-half normal solutions were made and these stored in
flasks provided with closely fitting rubber stoppers. By means of
4 series of graduated vials, these stock solutions were diluted and
mixed with the beet decoction at the time of using.

The fungi used were Botrytis vulgaris, Monilia fructigena, Stertg-
matocystis nigra, Mucor Mucedo, and Penicillium glaucum. The
first two may be and usually are parasitic, and have an optimum
temperature that is comparatively low; the last three are saprophytic

362 BOTANICAL GAZETTE [NOVEMBER

and grow well at temperatures considerably above the optimum for
the first two. It was thought by this selection to obtain more inter-
esting results than with forms more closely related physiologically.
Only pure cultures were used. In the test tube cultures from which
the spores were obtained for use, the fungi were grown upon cylin-
ders of potato or beet. In either case the liquid ia the tubes was
a decoction of sugar beets. Other nutrient substances were tried
for the test tube cultures, but these usually produced modifications
in the growth of the fungi and it was not found advisable to use
spores produced on different media in the course of a series of experi-
ments, the results of which were to be compared. The spores used
were always taken from cultures that were twelve to sixteen days
old. The desired temperatures were secured by means of incuba-
tors and a refrigerator.

CuarK has pointed out certain sources of error for Van Tieghem
cell cultures exposed to ordinary temperatures; but the placing of
cells, made up under ordinary laboratory conditions, at temperatures
ranging from 5° to 30° C., gave additional opportunity for error. i The
cells were not entirely closed until they had been left for several minutes
in the temperature at which they were to remain. This gave opiprs
tunity for adjustment of air pressure in the cell, but it did not in all
cases prevent the condensation of water vapor upon the cover glass.
The small drops of water thus formed not only increased the evapo-
rating surface but also modified the vapor pressure in the cell. The
small water drops adjacent to the hanging ones of the nutrient solu-
tion seemed to sometimes unite with them, thus changing both their
size and concentration. When the cultures were made in the dry
air of a furnace heated room no difficulty was experienced, but cells
made upon sultry days, or when the air of the culture room was
humid from any cause, gave a visible condensation when placed at
low temperatures. Even with the greatest precaution this difficulty
was not entirely overcome. '

It was found difficult to examine the cultures placed at besa
temperatures without interfering with the structure and condition ©
the cells. Examinations were made at temperatures as near as site
sible to those at which the fungi were growing, and results obtaine
from damaged cells were rejected. All cultures were observed every

1906] BROOKS—TEMPERATURE AND TOXIC ACTION 363

twenty-four hours and notes taken of percentage of germination,
length of germ tube, fruiting, and any peculiarities in germination
or development. More frequent observations would have been of
interest, but they were not made on account of the increased source
of error that would have been thus introduced. Any sources of error
that were not otherwise provided for were guarded against by always
making duplicate cultures. The experiments with the three chemi-
cals were always made at different times, and as control cultures
were made in every case, the growth of each fungus in a nutrient
medium at a particular temperature was tested six times.

The vitality of spores that had been subjected to the action of an
inhibiting toxic agent was tested by transfer to a nutrient non-toxic
medium, An attempt was made to accomplish this transfer by
Temoving the drop of the toxic solution with sterilized filter paper and
replacing it by a drop of beet decoction. This method left some
part of the former solution as well as any precipitate that had been
formed adhering to the cover glass, and was therefore adandoned.
All transfers that are concerned in the following data were made by
means of a sterilized platinum needle. The spores were in every
case transferred to a drop of beet decoction on a clean cover glass.
The medium used in the bottom of the cells was in this, as well as
in all other cases, the same as that of the hanging drop. It is quite
evident that the above method of transferring did not prevent a
small amount of the toxic solution being carried into the new drop
by the spores and the needle, but the results obtained indicated that
this small per cent. of the toxic agent either served as a very slight
stimulus to germination and growth or exerted no appreciable
influence,

Early in the work it was seen that results obtained from the
exposure of the fungous spores to the toxic agent must be considered
entirely apart from the data secured in cases where the mycelium
was acted upon by the toxic solution. Therefore, when a particular
toxic solution gave no germination at one temperature, but did at
others, the ungerminated spores were in no case transferred ; es
transfers were made only with those solutions that gave no germina-
tion even at the optimum temperature at the end of the given time.

By a series of preliminary experiments strengths of toxic solution

364 ‘BOTANICAL GAZETTE [NOVEMBER -

and time of exposure were determined, such as would give the greatest
contrast in the results obtained at the various temperatures.

DATA AND DISCUSSION.

In order to put the results obtained in a form as concise as pos-
sible, charts 1a—-12c have been prepared, and the greater part of the
data obtained is expressed in these by means of curves.

In charts 1a to 1o¢ inclusive, the abscissae indicate the tempera-
tures at which the fungus was kept in culture, and the ordinates
show the per cent, of germination at these temperatures. All the
points indicating per cent. of germination at the various temperatures
for a particular toxic solution are joined by solid or broken lines;
the strength of the toxic solution used is shown by the fraction placed
on or near the particular curve. For a further illustration of the
meaning of these charts, the curves in chart 2a may be considered.
These represent the data secured by using CuSO, with Monilia. With
an 7/16 solution no germination was obtained at 25° and 30°; but
at 15°, 12 per cent, of the spores germinated; at 10°, 30 per cent.;
and at 5°, 49 per cent.

In charts 1a to sc inclusive the results were obtained by exposing
the spores for twenty-four hours at the various temperatures in the
toxic solution indicated and then transferring them as previously
described. The charts are based entirely upon the data secured on
the first and second days after transferring. The solid lines indicate
the total germination at the end of the second day. The broken
lines show the per cent. of germination twenty-four hours after trans-
fering, Where the record of germination was the same for the two
days only the solid line is used, It will be noticed that only in 4
very few instances did spores germinate on the second day.

It is readily seen that in most cases the deleterious action of the
toxic agents increased very rapidly with the rise in temperature.
A comparison of the charts for the various fungi indicates that there
are some differences in reactions worthy of special note. Thus,
there is a marked drop between 5° and 10° in the germination curves
for Botrytis and Monilia, but for no other fungus. With Penicillium
the fall comes either between 10° and 15° or between 15° and 20°,
while with Mucor and Sterigmatocystis the downward curves begin

1906] BROOKS—TEMPERATURE AND TOXIC ACTION 365
100 100
32
q \
16
eee a
5 10 15 20 25 30 5 T 20 30
1a, Botrytis. CuSO,. .2a, Monilia.
7 —
a pis GE ae ee oe
16
al
A, n
os ™ 08
Ca ae 5 0 eee a

o/s

1b, Botrytis. H,SO,. 2b, Monilia.

10 15 20 25 3 J
1¢, Botrytis. HNO. 2c, Monilia.

366 BOTANICAL GAZETTE [NOVEMBER

o> roo

5 ! | 20 25 0 10 1§ 20 25 30
3a, Penicillium. CuSO,,. 4a, Mucor.
dy eae:
hd n
8 rt
IN“ n
4 16
bat :
9 I 2 5 10 15 20
36, Penicillium. H,SO,. 4b, Mucor.
Li
16
a5
8
eee
5 20 5 ad

1906] BROOKS—TEMPERATURE AND TOXIC ACTION 367
— —J 00
eee
16 |
\ ,
256 2
dit 128
Naas [ Z™.
| ENE 64
3 10 i 0 8 5 5 30
54, Sterigmatocystis. CuSO,. 6a, Sterigmatocystis.
= 700 a
Oe 64
a!
oh a | /
pe a
4 } /
[See Seoree }__—f-—
n n
v 16 16
eae be
\ /
Eee
5 10 I 20 25 3 0 i 20 a
5), Sterigmatocystis. H,S0,. 6b, Sterigmatocystis.
i goErerae 0 a
‘ 32
2 ee ———
j
n
16
ae) Fie sd
ee n
n [6
:
@ / y
‘4 ; 15 20 30 5 10 5 ee a
5¢, Sterigmatocystis. HNO,. 6c, Sterigmatocystis.

BOTANICAL GAZETTE

[NOVEMBER

368
st [00 an
256 a
ny
128
eo
12
a ; 0 64 arena ants
5 0 aaa bs 5 e~«dS 20 25. (30
7¢, Mucor. Cuso,,. 8a, Penicillium.
os 00 ree
iA ot
Fj et
a
/\\\ |
ny \
128 Hf \ | \
n n
2 \ a
act M
n : / :
5 10 20 2° a8 5 10 15 20 saa
75, Mucor. H.SO,. 8b, Penicillium.
oes 100 7 ee Wire
ZA ]
Z| 32
ee
n / / 32
128
[| |
fy
T EReliareae SSUES eee
a
ha pe
Inti
2
5 0
10 15 20 25 30 T 20
7¢, Mucor. HNO,. " 8c, Penicillium.

1906] BROOKS—TEMPERATURE AND TOXIC ACTION 369
100 7)
aes 100
256 /
/ ae n
n
hs Re ee 128
| V- /
/
7
/ n
| iw = | 128 @
ne Fe
ae L~ n jp —
Qe——~ }-———54 64
5 10 15 20 30 fi 10 15 20 z 30
92, Botrytis. CuSO,. toa, Monilia.
100.7 00
z x |
J| iB ied
In = :
eh 128 ; /
//r,
64
/"
jn 32 [ea
32
L
/ nt
; 32 132
0 —.
: io 15 20 25.30 5 10 15 20 - Re
9b, Botrytis. H,50,. 10b, Monilia
n 100
12
od ee
/ oe
ai ff weg
64 n aie sy
aa 128
fd
64,
BL
32 n
yor
15 20 25 0 5 10 15
9¢, Botrytis. HNO,. 10¢, Monilia.

370 BOTANICAL GAZETTE [NOVEMBER

at 15° or 20°. This variation may be the result of using solutions
that were, without regard to temperature, more injurious to some of
the fungi than to others; but strong concentrations, such as n/4 and
n/8 HNO,, when used with Mucor and Sterigmatocystis, have not
given the rise in the curves from 10° to 5° that has been repeatedly
obtained with Botrytis and Monilia. It should be noted that these
last two fungi are not only the ones that are most greatly injured by
the toxic agents, but also are those that require the least stimulus
for germination. Duccar (10) found that both Botrytis and Monilia
germinated readily in distilled water, but that Sterigmatocystis and
Penicillium did not germinate.

There is also a remarkable agreement in the minimum tempera-
ture for the germination of a particular fungus under certain condi-
tions and the location of the fall in its germination curve. Botrytis
and Monilia not only show the greatest increase in toxic effect on
passing from 5° to 10°, but they are also the only ones that had
germinated in the control cultures at 10° by the end of one day. With
Penicillium the CuSO, and HNO, curves show a tendency to drop
between 10° and 15°, while in the H,SO, curves the fall comes beyond
15°. Along with these data should be noted the fact that the control
with the H,SO, cultures gave no germination in one day, while those
with the HNO, and CuSO , cultures had germinated in this time.
This variation in the controls was probably due to a slight change 1n
the temperature of the refrigerator, together with the fact that 1 a
approaches the lower limit of temperature for obtaining the germina-
tion of Penicillium in one day (WIESNER 13). Mucor gave no germl-
nation the first day in the controls at 15°, with the exception of about
14 per cent. with the CuSO, series, and Sterigmatocystis in no instance
germinated in one day at this temperature. As has been already
mentioned, the curves for these fungi fall between 15° and 20° or at
a higher temperature. From these facts it is seen that the spores
exposed to a harmful agent and at the same time inhibited by cold
have not been greatly injured. g

In the cultures from which the data in charts 6a to roc inclusive
were obtained, the spores were in no instance transferred. The cells
in the CuSO, series remained at the temperature indicated for four
days; those with the acids were removed at the end of two days.

1906] BROOKS—TEMPERATURE AND TOXIC ACTION 371

In the former six daily observations were made, in the latter only
four. Control cultures of spores in beet decoction were kept with
the toxic cultures at all times. These controls were subjected to the
various temperatures for the same length of time as the other cultures.
The per cent. indicated in these charts do not in every instance
represent the actual germination, but were in all cases obtained by
dividing the per cent. of germination in the particular culture by that
in the control at the same temperature. It was found more difficult
to represent in graphical manner the results obtained from these
experiments, since the per cent. of germination did not always seem
to agree with the extent of the injury. The solid lines show the
germination at the time of the final removal from the given tempera-
ture. The per cent. of germination at the end of twenty-four hours
is indicated by the broken lines. These unite with the solid lines
as they approach the optimum temperatures. Where no broken line
is given the germination was the same at the end of the first day as
at the time of removal from the special temperature. The results
obtained at temperatures at which the controls had not germinated
were omitted from the curves. This accounts for the fact that a
number of the curves are not extended to the lower temperatures.

In all instances the injurious effects were least at the optimum
for the fungus. This optimum was determined by the germination
and development in the controls. The harmful effects were shown
by decreased germination as indicated in the charts and by abnormal
development. The toxic solutions that gave but partial germination
at the optimum for the fungus usually gave only abnormal develop-
ment above and below that optimum. Thus, Botrytis in n/32 HNO,
gave mycelial development approaching the normal only at 1 5° and
20°; Penicillium in 2/128 CuSO, gave medium growth at 20° but at
no other temperature, at 30° the germ tubes seldom became more
than a few spore diameters in length even after removal to a more
favorable temperature and many spores swelled without germinating.
Sterigmatocystis has its optimum above 25° and it is the only fungus
in which the injurious effects decreased above that temperature.
Both Mucor and Sterigmatocystis germinated and grew well at
35°, the other three fungi gave little or no germination at that tem-
perature,

372 BOTANICAL GAZETTE [NOVEMBER

The charts do not show the results obtained at low temperatures,
but in every instance cultures were placed at 5° and 10°. Spores
kept for two days in a particular toxic solution at a temperature so
cold that it inhibited their germination gave, upon removal to the
room temperature, a germination and development that was but
little inferior to that obtained from the fresh spores under like condi-
tions of medium and temperature. Spores inhibited at a tempera-
ture that did not prevent germination were more greatly injured.
Spores of Mucor gave fair growth in n/32 H,SO, and n/32 HNO,
after removal from 5°, but after removal from 10° did not germinate.
Sterigmatocystis spores in n/16 HNO, grew almost as well after
removal from 10° as from 5°, but in the cultures removed from 15°
(a temperature not inhibiting germination in the control) no germi-
nation was obtained.

A comparison of the curves obtained with the different chemicals
shows that those for weak concentrations of HNO, do not drop so
rapidly at high temperatures as the curves for weak solutions of the
other toxic agents. :

In order to obtain additional information in regard to the signifi-
cance of the results secured with the cells, a series of flask cultures
was made. In every instance 25°° of the given solution were placed
ina 100° flask, These flasks were sterilized after the introduction of
the solution. The effect of the toxic agent was determined by taking
the dry weight of the fungous growth at the end of the given time.
With the exception of n/64 CuSO,, duplicate cultures were made
and the average weight used in estimating the effect. Flask cultures
were made of Mucor, Penicillium, and Sterigmatocystis. The results
obtained from cell cultures were used as a basis in determining
what strengths of the toxic agents should be used in the flasks. So
much greater concentration was required to give injury in flask cul-
tures than in cells that no definite results were obtained with Mucor
and Penicillium. Also it was found that Penicillium would not grow
in flask cultures placed at 30° C., a temperature at which the fungus
grew well in the control cell cultures.

In the series with Sterigmatocystis the air in the incubator ™
dry, while that in the refrigerator was kept damp by the melting ys
It was feared that the evaporation from the flasks at 25° and 30

1906] BROOKS—TEMPERATURE AND TOXIC ACTION 373

might have been for this reason enough greater than at lower tem-
peratures to cause an appreciable change in the results, and the
series was repeated with the hygroscopic conditions more nearly uni-
form. Charts 12a and 11 give the results obtained from the first
series, while 11 and 126 show the results of the last series. In the
first set of experiments the fungus was allowed to grow two weeks, in
the last but one week; in the former the cultures for the various tem-
peratures were started at different times, in the latter all were started
_ on the same day and the spores used were from one stock culture.

In charts 11-12 the abscissae indicate temperatures as before,
but.the ordinates express percentages of dry weight instead of per-
centages of germination, The effect of temperature on the controls
is shown in chart 11. In this chart the curves were determined by
taking the greatest dry weight as 100 and estimating what per cent.
of this the weights secured at other temperatures were. In charts
12a and 12b these same controls are represented by the ordinates
marked too, In plotting the curves of these two charts, the weight of
fungus secured in a given toxic solution at a particular temperature
was compared in each case with the weight obtained in the control
at the same temperature. The results thus obtained are expressed
by the ordinates as mentioned above.

It will be seen that in most instances the curves in the two charts
are in close agreement. Where this is not true, as in the case of the
controls, the results obtained in the last series should be considered
the more reliable for the reason previously given. Taking total
growth as a standard, the injurious effects of the toxic agent have
decreased with rise of temperature. This decrease is rather to be
considered as the result of approaching the optimum for the fungus
than as a mere temperature effect. The effects produced by the
three chemicals were widely different. The injury resulting in the
CuSO, solutions was not so great, comparatively, at 15° as at 20°.
This was true of neither of the acids, Sulfuric acid checked the
Srowth at the lower temperatures, but in no case served as a strong
stimulating agent. Nitric acid gave similar injurious effects, but at
the higher temperatures served as a remarkable stimulus. It should
be remembered that a similar rise at 25° and 30° was obtained in
the cell culture curves for HNO,.

374

BOTANICAL GAZETTE

3. Reese

15 20

11, Sterigmatocystis.

25

30

Control

curves; a, for first series; b, for

second series.

300
ie
pen Ve
3
\,,
\ LS se
id |S \ ee be
Y
d
eS
15 0 25

124, Sterigmatocystis, first series.
a,n/256 CuSO,; b, n/192 CuSO,;
¢, n/32 HNO3; d, n/24 HNO.

. [NOVEMBER

200

30

ST
no

0 23

12b, Sterigmatocystis, second
series. a, 2/128 CuSO,; 6, 1/64
CuSO,; ¢, 2/20 H,SO,; ¢@, 2/10
H,SO,; e, n/20 HNO;; /, n/to
HNO,.

- The writer hopes by means of
further experiments to be able to
obtain additional information in re-
gard to the meaning of the difference
in action of the chemicals and the
significance of the varying effects upon
the different fungi. He wishes to
acknowledge his indebtedness to Dr.
B. M. Duccar, Professor of Botany
in the University of Missouri, for
suggesting the problem reported upon

-in this paper and for valuable advice

throughout the prosecution of the work,

New HaMpsHIRE COLLEGE OF AGRICULTURE
AND THE MECHANIC ARTS,
Durhan, N. H.

1906] BROOKS—TEMPERATURE AND TOXIC ACTION 375

LITERATURE CITED.

. Taree, Die Temperaturgrenzen d. Schimmelpilze 10, 36. 1896.

2. NAGcrut, Die niederen Pilze 30, 200. 1877.
3. Heer, Ueber die Wirksamkeit von Desinfektionsmitteln bei héherer
atur. Cent. Bakt. 9: 221-228. 1891 ;

4. Pasteur, Compt. Rend. 84:206. 187

5. Coun, Beitr. z. Biol. Pfl. 2:255, 259. 1877

6. BREFELD, Unters. ii. d. Spaltpilze ro. 1878

7. RicHet, C., La chaleur animale. Paris. 1889

8. Marnews, A. P., The relation between solution tension, atomic volume,
and the physiological reaction of the elements. Amer. Jour. Physiol. ro:
290-323. 1904.

9. CLARK, J. F., On the toxic effect of deleterious agents on the germination
and development of certain filamentous fungi. Bot. GAZETTE 28: 280,
378. 1899.

10. Duccar, B. M., Physiological studies with reference to the germination of
certain fungous spores. Bot. GAZETTE 31:38. I90I.

11. FERGUSON, MARGARET C., A preliminary study of the germination of the
spores of Agaricus campestris and other basidiomycetous fungi. U.S
Dept. Agric., Bureau Pl. Ind., Bull. 16. 1902.

12. CLARK, J. F., On the toxic properties of some copper compounds with
special reference to Bordeaux mixtures. Bot. GAZETTE 33:26. 1902.

13. Wiesner, J., Untersuchungen iiber den Einfluss der Temperatur auf die

Entwicklung des Penicillium glaucum. Sb. Wien. Akad. 68:5-16. 1873-

THE EMBRYOGENY OF SOME CUBAN NYMPHAEACEAE.
MELVILLE THURSTON CooK.
(WITH PLATES XVI-XVIIL.)

THE taxonomic position of the Nymphaeaceae has always been
somewhat doubtful. The anatomy of these plants is more nearly
_ that of the monocotyledons, while the venation of the leaves would
indicate that they are dicotyledons. A few years ago researches in
this family were stimulated by Lyon’s studies (17, 18) on the embry-
ogeny of Nelumbo, in which he came to the conclusion that they should
be classified among the monocotyledonous families in the series
Helobiae. Lyon’s views were strengthened by my own paper on
the embryogeny of Castalia odorata and Nymphaea advena (7), by
SCHAFFNER’S paper on morphological peculiarities of the Nymphae-
aceae and Helobiae (26), and by Yorx’s embryological studies on
Nelumbo (28). But Conarp (5, 6) in his studies in this same family
took exceptions to this view, and holds to the idea that they should
be classified among the dicotyledons. More recently, MoTTIER (20)
has declared his belief that they are anomalous dicotyledons. How-
ever, he does not claim to have made any study of the Nymphaeaceae,
but confines his studies to well recognized dicotyledonous species.

Immediately following Lyon’s paper (18) on the embryogeny of
Nelumbo, CAMPBELL (4) raised the question as to whether other
genera of the Nymphaeaceae might not also be monocotyledonous,
and called attention to the fact that the structure of the flowers and
character and arrangement of the vascular bundles in Cabomba and
Brasenia were very similar to some of the Alismales; also “ that the
form of the leaves is often very suggestive of the sagittate leaves of
Alisma or Sagittaria.”’

In consideration of the differences of opinion indicated above the
writer accepted an opportunity to make a study of certain tropical
species, hoping that additional light might be thrown on this very
interesting family. :

SCHAFFNER (26) called attention to the fact that it is in reality
much easier to read monocotyledonous than dicotyledonous charac-
Botanical Gazette, vol. 42] (376

1906] COOK—CUBAN NYMPHAEACEAE 377

ters into the flowers; that while the genus Castalia has been described
as having four sepals, C. odorata usually has only three, though some-
times by an expansion of the receptacle one segment of the second
cycle is more or less exposed, while in C. tuberosa the displacement is
normal, This led me to make a similar study of C. pubescens. In
this species I found that 80 per cent. have the first segment of the
second cycle exposed, while 20 per cent. have the second segment
of the second cycle more or less exposed, thus showing five parts.
SCHAFFNER also.called attention to certain other secondary resem-
blances, such as number and arrangement of ovules and ovularies,
between the Nymphaeaceae and well-recognized monocotyledonous
plants,

The vascular bundles of all the species referred to in this paper
were also studied, but gave no facts other than those already well-
known, the bundles in all cases being of the well-recognized closed
type and arranged in the stems after the usual manner of this family.

On account of the large amount of gummy substance surrounding
the ovules, considerable difficulty was experienced in getting a killing
fluid to penetrate. This was especially true for Brasenia purpurea
where the gummy substance was most abundant. Picric-acetic solu-
tions proved to be the best fixing agents, while chrom-acetic and
the Flemming’s solutions were unsatisfactory and could be used only
for the development of the embryo sac and the stamens.

_THE EMBRYO SAC.

The formation of the embryo sacs in all genera is very similar,

and in fact practically the same as described in my first paper (7).
I will not give a discussion of each, therefore, but will give a general
outline and present a series of figures illustrating the more important
points, with special attention to the mature sac and the changes at
the time of fertilization and immediately following.
_ The archesporial cell develops from the hypodermis (fig. 72) and
1s easily recognized. An indefinite number of tapetal cells, usually
varying from four to eight, are then produced. Three or four mega-
spores are then formed. The four may be produced either by a
regular division of the mother cell into four cells; or occasionally
by the division of the mother cell into three cells, followed by a divi-
Sion of the middle one (fig. 2).

378 BOTANICAL GAZETTE [NOVEMBER

The innermost megaspore is functional and develops rapidly into
the embryo sac at the expense of the other megaspores and the tapetal
cells. This enlarged cell (fig. 3) now touches the epidermis at the
micropyle and passes rapidly through the two-, four-, and eight-
nucleate stages. The mature embryo sac is very small and straight,
and the enlargement is principally in the direction of the long axis
of the ovule. Starch is usually very abundant and persists through-
out the two- and four-nucleate stages, and in Brasenia purpurea
and Cabomba piauhiensis usually throughout the eight-nucleate stage.
It gradually disappears, first from the micropylar end of the sac and
finally from the antipodal end (fig. 6). It probably undergoes modi-
fication to form the first food for the development of the embryo
and endosperm.

Occasionally two embryo sacs were produced, but one was always
absorbed by the other (fig. 7). This was more frequent in Cabomba
piauhiensis than in any other species studied. Fertilization occurs
almost immediately upon the completion of the eight-nucleate stage of
the sac. The same very pronounced sclerification of the inner part of
the epidermal cells (jig. 4), previously observed by me (7) for Cas-
talia odorata, was observed in the tropical species of Castalia studied,
but not in the other genera, The actual penetration of this epi-
dermal wall by the pollen tube was observed in only a few cases. In
fertilization the pollen tube (fig. 4) enlarged and stained so deeply
that it was impossible to observe what fusion of nuclei did occur.
At the time of fertilization the polar nuclei are very large, usually
rather indistinct, and unite at the micropylar end of the sac just
below the egg apparatus. At the same time the antipodals, which
are very inconspicuous, undergo degeneration (fig. 4). The syner-
gids may persist a short time after fertilization (figs. 5,6, 7), but usually
disappear very quickly. They are most persistent in Cabomba
piauhiensis.

The primary endosperm nucleus, which is now very large and ced
spicuous, moves to the antidopal end of the sac (jigs. 5, 6), where it
divides (figs. 7, 8, 20), and a very delicate wall is formed across the
sac between the two daughter nuclei. This wall can be observed
without great difficulty in Nymphaea advena (jig. 8) and in Castalia
am pla (fig. 20), but is very difficult to see in the other species studied.

1906] COOK—CUBAN NYMPHAEACEAE 379

The nucleus next to the embryo divides repeatedly, thus forming the
endosperm which will be described later. The nucleus in the anti-
podal end acts slightly differently in the different species and will
hereafter be designated the nucleus of the nucellar tube.

In Nymphaea advena a long tube-like extension of the sac is
now formed through the nucellus, beginning with the antipodal end
of the sac and extending to the chalazal end of the ovule. The very
large and conspicuous daughter nucleus of the antipodal end, formed
by the division of the endosperm nucleus, enters this tube, which
will be called the nucellar tube, and travels to the chalazal end of the
ovule, where it undergoes disintegration (figs. 8, 12, 13, 14). When
the embryo is in the two-celled stage, the tube and nucleus have
traveled about two-thirds the length of the ovule (figs. 8, 12); and
when the embryo has reached the quadrant or octant stage, the tube
is complete (figs. 13a, 13b). In one case only (fig. 13) the tube
nucleus had divided. After this time it disintegrates (jig. 14). In
its early development the tube is filled with protoplasm which to all
appearances is traveling towards the embryo sac. This is exactly
the condition observed by me in Nymphaea advena and Castalia
odorata and described in my first paper (7).

In Castalia ampla (fig. 20) the nucellar tube is a short thick sac
which is separated from the embryo sac by a constriction and by a
thin wall, and which contains a very large nucleus and a large amount
of protoplasm, As the embryo increases in size, the embryo sac
enlarges, encroaching upon this nucellar tube sac and absorbing its
contents (fig. 21), The formation of this tube sac is very similar
to that described by JoHNson (12) for Sawrurus cernuus, except
that in that species the tube ‘sac is relatively larger and persists in
the mature seed,

In Castalia pubescens the nucellar tube is much slower in develop-
ment, much less conspicuous, and apparently of much less importance
than in any of the other species studied. Extending from the antip-
odal end of the sac to the chalazal end of the ovule is a great mass
of elongated cells (fig. 24) which are much richer in protoplasmic
contents than the other cells of the nucleus. The greater part of this
mass of cells disintegrates slowly and thus is formed a small tube
reaching usually not more than one-half the length of the ovule

380 BOTANICAL GAZETTE [NOVEMBER

(fig. 9a). The tube is flat (jig. 9b) instead of cylindrical as in the case
of the other species. This tube is usually completed just before
the appearance of the cotyledonary ridge of the embryo. The nucleus
was observed in the antipodal end of this tube but apparently dis-
integrated, and did not pass to the opposite end of the tube as in the
case of the other species.

In Brasenia purpurea and Cabomba piauhiensis, the nucellar tube
is long but very small, There is a rapid disintegration of the nucellar
tissue to form the tube before the tube nucleus begins its passage.
The tube nucleus gradually disintegrates, and has entirely disappeared
before it reaches the chalazal end of the tube (jigs. 7, 10, 11); the
chalazal end of the tube is considerably enlarged, is not so definite
in outline as in Nymphaea advena, and contains fragments of the
cell walls (fig. 17).

In my previous discussion (7) I called attention to the fact that
the behavior of the endosperm nucleus is similar to that of Sagittaria
variabilis as described by SCHAFFNER (25), except that in S . variabilis
there is no nucellar tube elongation; also, that judging from the
studies of WrEGAND (27) and HoLrerty (10) on Potamogeton it is
possible that a similar condition may be found in that genus.

Since that time, Hai (9), in his studies on Limnocharis emarginata,
in which he finds a single polar nucleus, says:

The upper polar nucleus, when it has approached the antipodal end of the
sac, divides transversely. The lower daughter nucleus remains in the position
of its formation, being cut off by a wall across the sac and forming a large cell
which does not divide further, but finally disappears through the encroachment
of the endosperm... . . The upper daughter nucleus travels back towards
the egg apparatus, and by its further division forms the endosperm.

STRASBURGER (23) describes a similar action of the endosperm
nucleus of Ceratophyllum submersum, in which, after the first division,
the nucleus in the antipodal end of the sac does not divide, while the
nucleus of the micropylar end forms the endosperm. :

CAMPBELL (1) in his discussion of Naias flexilis and Zannichellia
palustris describes a condition which further study may prove to
be similar to the Nymphaeaceae. In discussing Naias he says:

A peculiarity noted, which was also observed in Zannichellia, was the presence
of a single large nucleus close to the antipodals, which was conspicuous at 2n
early period and behaved much like the nucleus of the suspensor. Whether this

1906] COOK—CUBAN NYMPHAEACEAE 381

was the lower polar nucleus or one of the two endosperm nuclei resulting from
the first division of the primary endosperm nucleus could not be determined.
Whichever is the case, it never divides, and all the endosperm nuclei arise from
the division of the other primary endosperm (or polar) nucleus. The endosperm
is limited, there being usually no trace of cell formation.
In discussing Zannichellia palustris he says:

As in Naias, there is evident soon after fertilization a large nucleus just above
the antipodal cells, which undergoes no division, but increases very much in size.
This is more variable in size than in Naias; not infrequently it could not be
detected in the later stages, and in several instances it looked as if it were under-
going disintegration.

Previous to this time, JoHNSON (12) had published his studies on
Saururus cernuus, in which he described a division and behavior of
the endosperm nucleus very similar to what I described for Nym-
phaeaceae, and the formation of a nucellar tube sac intermediate
between what I have described in this paper for NV ym phaea advena( ?)
and Castalia ampla, JOHNSON (15) has since called attention to
other genera of the Saururaceae (Anemiopsis and Houttuynia) which
possess this character.

In my previous discussion of this subject (7), I expressed the
opinion that the physiological significance of this nucellar tube and
nucleus presented a very interesting problem, which should be con-
sidered in connection with the function of the antipodals. I called
attention to the fact that in Ranunculaceae, Sparganium, and Vail-
lantia the antipodals appeared to furnish nourishment for the embryo;
that the peculiar haustorial development of the antipodals of Vail-
lantia, the enlargement of the lower antipodal in Aster, the accumu-
lation of endosperm in the antipodal region of Alyssum, and the
large lower nucleus formed by a division of the endosperm nucleus
(nucellar tube nucleus) in Sagittaria and the Nymphaeaceae showed
a resemblance which I believed to indicate a similar physiological
function. At about the same time Ikepa (11) published the results
of his studies on the physiological functions of the antipodals, in
Which he demonstrated by microchemical observations that the antip-
odals of Liliaceae possessed very important physiological functions.

JoHNson (14) also considers the antipodals of considerable
Physiological importance in certain of the Piperaceae, in which he
describes them as increasing in size and sometimes in number. It

382 BOTANICAL GAZETTE [NOVEMBER

seems very evident that this nucellar tube and its nucleus, which has
common origin with the endosperm nuclei, are important structures for
supplying food to the embryo through the agency of the endosperm.
In Castalia pubescens, where the tube is developed, the same function
is performed, first by the axial core of elongated cells (fig. 24) and
later by the small nucellar tube (fig. 9).

YorK (28) in his studies on Nelumbo did not observe the forma-
tion of a nucellar tube with its nucleus, but claims that both nuclei
formed by the first division of the primary endosperm nucleus divided
repeatedly. However, it may be that York failed to observe the
first division of this endosperm nucleus, that the tube nucleus dis-
integrates very quickly as in Castalia pubescens, and that he really
observed the secondary divisions of the daughter endosperm nucleus
in the micropylar end of the sac.

ENDOSPERM,

The development of the endosperm in this family presents two
distinct types, Nymphaea, Castalia, and Nelumbo illustrating one,
and Brasenia and Cabomba the other. The first type shows the
formation of cell walls, that is, a cellular endosperm throughout its
entire development; while the second type forms cell walls only in
the latter part of its development. The formation of the two types
of endosperm by closely related plants has been noted by several
investigators.

In the first type the first cell walls are formed across the sac
(figs. 13a, 20, 23), but gradually become more irregular and extend
in various planes (figs. 21, 24, 25). At first the cells contain eee
siderable protoplasm and the entire endosperm is very active, but in
a short time it seems to have reached its maximum activity and
importance. In Castalia pubescens, at about the time and following
the appearance of the cotyledonary ridge, the endosperm cells imme-
diately over the plumule show a marked difference from the sur-
rounding cells (fig. ga,x). They are slightly smaller, more delicate,
and are probably the cells which give nourishment directly to the
embryo. In this same species the endosperm may penetrate the
antipodal end of the nucellar tube a short distance (jig. 23):

In the second type, represented by Brasenia and Cabomba, the

1906] COOK—CUBAN NYMPHAEACEAE 383

protoplasm is very dense and the cells at first divide rapidly, but
no cell walls are formed (figs. 10, 33). After the embryo has passed
the stage indicated in fig. 34, the endosperm appears to become
thinner and does not stain readily until the embryo is near maturity.
The protoplasm then becomes very dense, cell walls are formed,
and one layer (occasionally two or three in Brasenia) of cells is
developed which completely surrounds the embryo (jig. 40). This
endosperm is usually thicker and forms two or more layers in a zone
around the embryo at the point of origin of the cotyledonary lobes
(jig. 38, x), and are very thin just below the root tip (fig. 38, y). It
appears that the endosperm in Brasenia and Cabomba must perform
a more important function in the germination of the embryo than
in the species of the other genera.

JOHNson (14) in his studies on Piperaceae has expressed the
opinion that the “embryo sporophyte of the second generation is
never nourished by the parent sporophyte directly, but always
through the intermediate gametophyte.” The development and
action of the endosperm in Nymphaeaceae confirms JOHNSON’S
conclusions. :

In all species studied there is a pronounced lateral enlargement of
the embryo sac, at the expense of the nucellus, to accommodate the
creasing endosperm and growing embryo (compare jigs. 24 and 25).

EMBRYO.

: The development of the embryo shows a very wide range of varia-
tion. The embryo of Nymphaea advena (?) of Cuba follows almost
exactly the same course as previously described by the writer for
Nymphaea advena of the northern United States. The fertilized egg
first divides transversely (fig. 12), and then two longitudinal walls
result in a spherical embryo of eight cells. Successive cell divisions
occur, but the spherical character is retained for some time, after
Which there is an excessive growth on the side next to the micropyle,
forming a suspensor by which the embryo is attached to the nucellus,
and a flattening on the opposite side, thus giving the embryo the shape
“ a short blunt cone, or rather of a pear (fig. 16). In this respect it
differs from NV . advena of the north, in which the suspensor is much
ore rudimentary and does not develop until much later. At this

384 BOTANICAL GAZETTE [NOVEMBER

time it somewhat resembles the embryo of Sparganium simplex as
described by CAMPBELL (3); but without the younger stages of S.
simplex and more of the young stages of NV. advena (?) it is impos-
sible to say whether this resemblance is more than superficial. From
the large end of this conical embryo a cotyledonary ridge is now pro-
duced which extends almost entirely around this end and almost com-
pletely encloses the plumule (fig. 17), while in N. advena of the north
it extends only a little more than half the distance around the embryo.
This monocotyledonous character is very evident in embryos dis-
sected out of the sacs. Two cotyledonary lobes are next developed
from this cotyledonary ridge, thus giving it the dicotyledonous char-
acter (jig. 18). The development of this dicotyledonous character
is much earlier and much more pronounced than in N. advena of
the north. A number of embryos were cross sectioned and examined
very carefully and considerable variation was found in the prominence
of this character. In one case it was so great as to give the appear-
ance of two equal cotyledons (fig. 19). The development is strik-
ingly similar to that of Nelumbo as described by Lyon (18) and
York (28),

SCHAFFNER (26) dissected the advanced embryos of VV __ advena
out of the sacs and clearly demonstrated the formation of the two
cotyledonary lobes. He did not contradict my conclusions, as stated
by Morrrer (20), but made his studies from older embryos than
I was able to secure at the time my studies were made.

The embryos of the two species of Castalia show some differences
and also differ from Castalia odorata, In Castalia ampla a Pro
embryo is formed which may consist of as many as six cells in linear
arrangement (figs. 20, 21). The terminal cell then divides by.*
longitudinal wall, which is followed by a similar division in the next
cell (fig. 21). The four cells thus formed then divide by a second
longitudinal wall at right angles to the first. By repeated division,
this mass of cells now forms a spherical embryo supported by 2 sue
pensor of four or five cells in linear arrangement (fig. 22). One we
more of these suspensor cells, usually the basal, may divide longi
tudinally. On account of the seed pods sinking soon after fertiliza-
tion it was impossible to follow the development in this species further.

In Castalia pubescens the embryo develops in the same manner,

1906] COOK—CUBAN NYMPHAEACEAE 385

except that there are usually not more than four cells in the pro-
embryo, With the formation of the spherical embryo the suspensor
increases in diameter and the cells usually divide longitudinally
(figs. 24, 25, 26). After the spherical stage the embryo gradually
assumes a pear-shape, and a little later develops the collar-like
ridge which extends about two-thirds around the embryo at its
greatest circumference. This condition was readily demonstrated
by two series of longitudinal sections cut at right angles to each
other and a series of cross sections (figs. 27-30). Fig. 27 is from a
longitudinal section passing through the middle (#) and between the
two points of the crescent-shaped cotyledonary ridge (y). Fig. 28 is
from a longitudinal section at right angles to jig. 27 and passes
through the cotyledonary ridge near the points of the crescent (2).
Fig. 29 is from a series of cross sections of an embryo of corresponding
age to figs. 27 and 28. Fig. 30 is from section d of fig. 29, i, & at
about the point where the cotyledonary ridge arises. Fig. 31 is
reconstructed from a series of sections of a slightly older embryo.
At this time there was no external indication of the two cotyledonary
lobes, but the rapid division of cells just within the points of the
crescent-shaped cotyledonary ridge (fig. 30¢, 1) indicates their early
formation.

It was impossible to follow the development of the embryo beyond
this point, because of the withdrawal of the seed pods from the sur-
face of the water to the bottom, where they were quickly buried in
the mud. This withdrawal commenced soon after pollination and
was accomplished by the spiral-like formation of the peduncle which
gradually contracts, However, SCHAFFNER (26) was able to dissect
the young embryos of Castalia odorata out of their sacs and makes
the following statement concerning them:

apparent. There is the same opening on one side, and on the back a connection
of the two lobes, only to a less extent. Unless special care were taken in recon-

386 BOTANICAL GAZETTE [NOVEMBER

structing such an embryo from serial sections, one might readily take it for a
dicotyl. It will be evident, however, from a comparison of the figures that the
Castalia embryo represents only the extreme of the lobing shown in Nelumbo
and Nymphaea.

The formation of the suspensor is entirely different from what
I observed in C. odorata, but corresponds with Conarn’s (5, 6)
observations. The suspensor disappears soon after the formation
of the cotyledonary ridge.

The development of the embryos of Brasenia purpurea and
Cabomba piauhiensis is practically the same, but since C. piauhiensis
is much more easily sectioned and furnished much better prepara-
tions, most of the drawings were made from it, The fertilized egg
divides by the formation of cross walls and produces a proembryo
of three or four cells in linear arrangement (figs. 32, 33a, 34, 35). The
terminal cell then divides, forming a quadrant (jig. 33a), then it
forms the octant, and then a large spherical embryo supported by a
short suspensor of two or three cells which usually divide longitudi-
nally (figs. 34, 35, 36). As the embryo increases in size, it becomes
more or less flattened against the walls of the sac and develops the
cotyledonary ridge (jig. 36, x) similar to the two genera just described,
except that this ridge extends almost entirely around the plumule,
thus forming a pit with the plumule in the center. The dicotyledonous
character produced by the development of the cotyledonary lobes
appears very early. Only by the most careful examination of the
intermediate stages at the time of the first appearance of the cotyle-
dons, and by the most careful cross sections was it possible to demon-
strate the common origin of these two cotyledonary lobes. They
develop very early and the edges and tips come together, thus enclos-
ing the plumule in a short, hollow cone (fig. 37). After this the
development of the embryo is a mere increase in size (figs. 38, 39),
accompanied by the modification of the endosperm previously referred
to. The suspensor persists until the embryo is almost mature and
then disintegrates.

It will be noted that the young embryo of Nymphaea advena (?)
is similar to the embryos of Lysichiton kamtschatense as described by
CAMPBELL (2); and of Ceratophyllum submersum as described by
STRASBURGER (23). The young embryos of Castalia ampla, C.

1906] COOK—CUBAN ._NYMPHAEACEAE 387

pubescens, Brasenia purpurea, and Cabomba piauhiensis all have the
same general « character as Nymphaea advena, except that they pos-
sess suspensors. ‘They also show some resemblance (which may be
superficial) to the embryo of Sparganium simplex as described by
CAMPBELL (3). They also resemble the embryos of Naias flexilis
and Zannichella palustris as described by CAMPBELL (1), Potamoge-
ton foliosus and P. natans as described by WIEGAND (27) and Hot-
FERTY (10), and Limnocharis emarginata as described by HALL (9g)
except that they do not possess the large basal cell of the suspensor,
The late development of the suspensor in Nymphaea advena ( ?) of
Cuba and N. advena of the north, as previously described by me,
may confirm in some measure COULTER and CHAMBERLAIN’S view
that the Alisma-type of monocotyledonous embryo is primitive and
that the suspensor in the Pistia type has been suppressed.

It will also be noted that the origin of the cotyledonary lobes in
all cases is from a crescent-shaped cotyledonary ridge about the
larger part of the embryo, and that my results coincide with the con-
clusions reached by Lyon, ScHAFFNER, and York. This point in
Conarn’s studies is illustrated by a single figure (48, d) of Castalia
caerulea. This figure agrees exactly with fig. 30 and text jig. 2, d, e
of my first paper, with Lyon’s fig. 10, and Yorx’s fig. 33 of Nelumbo.
However, my figures are parts of series which illustrate the true
~ Monocotyledonous character of the embryo; and this monocotyle-
donous character of C. odorata was afterwards demonstrated by
SCHAFFNER who dissected the embryos out of their sacs.

RICHARD (21) referred to the embryos of the grasses, Nelumbo,
Ruppia, Hydrocharis, and Zostera as embryons macro podes, and
SCHAFFNER (26) confirms this view and expresses the opinion that the
Massive expansion and lobes of Halophila, Ruppia, Zostera, Nelumbo,
Nymphaea, and Castalia are not homologous with the cotyledons,
but are specially developed absorbing organs.

The figures of this paper show a striking resemblance to the
figures of anomalous dicotyledons by Lewis (16) and Mortrier
(20). However, the flowers show more monocotyledonous than
dicotyledonous characters, while only the leaves may be considered
4S uniformly presenting dicotyledonous characters. It appears,
therefore, that the Nymphaeaceae can be more properly classed as

388 BOTANICAL GAZETTE [NOVEMBER

anomalous monocotyledons, rather than as anomalous dicotyledons
as suggested by Morrrer.
3 SUMMARY.

1. The development of the embryo sac is practically the same in
all species.

2. In all species the endosperm nucleus divides and the daughter
nucleus in the antipodal end enters a nucellar tube or sac which
penetrates the nucellus.

3. This nucellar tube or sac is apparently for the purpose of
transferring food from the nucellus to the endosperm, from which it
is transferred to the embryo.

4. The endosperm is of two types: the cellular in Nymphaea and
Castalia, and the nuclear followed by the cellular in Brasenia pur-
purea and Cabomba piauhiensis.

5. The character of the endosperm in the late stages of Brasenta
purpurea and Cabomba piauhiensis indicates a greater importance
in germination than in the other genera. J

6. The embryo of Nymphaea advena( ?) originates as a spherical
mass of cells and later develops a cotyledonary ridge and suspensor,
while the other species develop embryos consisting of a single row of
cells, from which is formed a spherical embryo supported by a sus-
pensor. A crescent-shaped cotyledonary ridge is then developed, —
ranging from two-thirds to almost the entire distance around the
embryos.

7. With the development of the cotyledonary ridge, two cotyle-
donary lobes are produced which may readily be mistaken for two
cotyledons.

Estaci6n CENTRAL AGRONOMICA,

Santiago de las Vegas, Cuba.

Note: The material from which these studies were made was submitted
to specialists in taxonomy. There was some difference of opinion as to whether
the Nymphaea was a large-leaved form of N. advena or another closely ae
species. Castalia pubescens is an introduced species from eastern India, Philip-
pines, Java, and Australia. It was collected in a large lagoon near San A
de las Bafios in Havana Province. Nymphaea advena(?) was collected in oe
river at San Cristobal and in a small lagoon south of Herredura in Pinar a
Rio Province; all other species in this same small lagoon. Specimens ff
these species have been deposited in the New York Botanical Garden.

1906] COOK—CUBAN NYMPHAEACEAE 389

Nu

a

I

Sal
°

aad
Nw

x LITERATURE CITED.

. CAMPBELL, D. H., A morphological study of Naias and Zannichellia. Proc.

Calif. Acad. Sci. III. 1:1-62. pls. 1-5. 1897.
Notes on the structure of the embryo sac in Sparganium and Lysichi-
ton. Bot. GAZETTE 27:153-166. pl. 26. 18
—— Studies on the flower and embryo of Sparganiii. Proc. Calif.
Acad. Sci. III. 1:293-328. pls. 46-48. 1897.
— On the affinities of certain anomalous dicoyledons. Amer. Nat.
. figs. 2. 1902.

36:7
cians ‘i S., Note on the embryo of Nymphaea. Science N. S. 15: 316.

1902.

The water lilies: a monograph of the genus Nymphaea. The Car-
negie Institution of Washington, Publication No. 4. 1905.

Coox, Met. T., Development of the embryo sac and embryos of Castalia
odorata and 'N ymphaea advena. Bull. Torr. Bot. Club 29:211-220.
pls. 12-13. tg02.

2

. Coutrer, J. M., and CHamBerzaty, C. J., Morphology of angiosperms.

1903.
Haut, J. G., An embryological study of Limnocharis emarginata. Bor.
Gazz ETTE 33:214-2

19. pl. 9. 1902.
- Hotrerry, G. M., Ovules and embryo of Potamogeton natans. Bort. GAZETTE

31: 339-346. pis. 2-3.

IQOT.
. IkepA, T., Studies in the physiological functions of the antipodals and related

pidacean of fertilization in meer ceae. . Trycirtis hirta. Coll. Agric.
Imp. Univ. Tokyo 5:41-72. pls. 3-

- Jounson, D. S., On the Komen of Gaus cernuus. Bull. Torr.

Bot. Club 27: obs-ai pl. 23.

On the endosperm and pee of P eperomia pellucida. Bor.

GazETTE 30:1-11. pl. 1. 1900.

On the — of certain Piperncese. Bor. Gzetr® 34:
321-340. pls. g-10. 1

——— Seed development in the Piperaceae and its bearing on the order.
Johns Hopkins Univ. Circ. 178: 29-32

1905.
- Lewis, C. E., Studies on some ‘scuaieds dicotyledonous plants. Bot.

GAZETTE ais 127-138. pls. 7-8.

1904.
- Lyon, H. L., Preliminary note on the embryogeny of Nelumbo. Science

N.S. 13:470. IQOT.

Observations on the embryogeny of Nelumbo. Minn. Bot. Studies
2:643-655. pls. 48-50. 1901.

~——— The embryo of the angiosperms. Amer. Nat. 39:13-34- figs. 11.
1905.

- Mornier, D. M., The embryology of some anomalous dicotyledons. Annals

of Botany 19: 447-463. pls. 26-27. 1995-

3990, BOTANICAL GAZETTE [NOVEMBER:

21. Ricwarp, L. C., Analyse botanique des embryons endorhizes ou mono-

seine et particulitrement de celui des Graminées. Annales Paris
at. Hist. 1'7:223-251, 442-487. 1811

a2. Sauer ETHEL, Evolution of the monocotyledons. Bot. GAZETTE 37:
325-345. figs. 6. 1904.

23. STRASBURGER, E., Ein Beitrag zur Kenntniss von Ceratophyllum submersum
und philogenetische Erérterungen. Jahrb. Wiss. Bot. 3'7:477-526.
pls. Q-II. 1902.

24. SCHAFFNER, J. H., The embryo sac of Alisma hints Bot. GAZETTE
21:123-132. pls. Q-I0.

25. The life history of Sagittaria variabilis. Bot. GAZETTE 23: 252-273.
pls. 20-26. 1897.
26. Some morphological or of the Nymphaeaceae and Helobiae.

Ohio Nat. 4:83-92. ls. 5-7.
27. WieGAND, K. M., The ae cncon é the mig, sac in some monocoty-
ledonous plants. Bot. GAZETTE 30:25-47. pls. 6-7. 1g00.
28. York, H. H., The embryo sac and embryo of Nelumbo. Ohio Nat. 4:167-
176. 1904.
EXPLANATION OF PLATES XVI-XVIII.

Figures of the same relative value are drawn with the same lenses: igs.
1-7 with Zeiss no. 4 oc. and 74 obj.; figs. 12-16, 20-28, 30, 32, 36, and 4o with -
no. 4 oc. and DD obj.; figs. 8-11, 17-19, 29, 31, 37-39 with no. 4 oc. and A
we PLATE XVI

Fic. 1. Archesporial cell of Brasenia purpurea.

Fic, 2. Megaspores of Nymphaea advena (?).

Fic. 2. Uninucleate embryo sac of N. advena (?).

_ Fic. 4. Mature embryo sac of Castalia pubescens, showing entrance of pollen
tube (pt).

Fic. 5. Embryo sac of C. pubescens just after fertilization, showing fertilized
egg =a remains of synergids (sym), and the endosperm nucleus

G. 6. Embryo sac of Brasenia purpurea just after fertilization, showing
egg oe aoe: (syn), endosperm nucleus (end mi); and starch in the antipodal
end of :

Fic. : Embryo sac of Cabomba piauhiensis, poowlie fertilized egg (0); the
* two synergids (syn), the endosperm nucleus (end nu) after first division, and
the remains of a second sac (e s).

Fic. 8. Embryo sac of N. advena ( ?), showing two-celled embryo, the nucellar
tube, and the two daughter cells of the endosperm nucleus (e) separated by
a. wall; the tube is about three-fourths the length of the ovule.

Fic. 9a. Embryo sac of C. pubescens, showing large pear-shaped embryo
with region of modified endosperm (x), and = nucellar tube. .

Fic. 9b. Cross-section of nucellar tube of

1906] ~ COOK—CUBAN NYMPHAEACEAE 301

Fic. 10. Embryo sac of C. piauhiensis, showing two-celled embryo and
nucellar tube. The endosperm nucleus has divided and one daughter cell entered
the tube (nin), while the other has remained in the sac and undergone first
division (end).

Fic. 11a. Embryo sac and mature nucellar tube of C. piawhiensis with
spherical embryo; the thin endosperm filled the sac at this time.

Fic. 11b. Cross-section of tube of rza at smallest part.

Fics. 12-19.. Nymphaea advena(?).

Fic. 12a. Two-celled embryo with daughter nucleus of endosperm nucleus
(en) after first division; same as fig. 8

Fic. 12b. Nucellar tube nucleus of figs. 8 and 12a.

PLATE XVII

Fic. 13a. Section of spherical embryo in octant. stage surrounded by endo
sperm. :

Fic. 136. Lower part of the nucellar tube of 1 3a in which the nucellar tube
nucleus was divided.

Fic. 14. Mature nucellar tube nucleus.

Fic. 15. Spherical embryo.

Fic. 16. Pear-shaped embryo at time of origin of cotyledonary ridge and
with well-developed suspensor.

Fic. 17. Cross-section of embryo a little older than that in fig 16.

Fic. 18. Cross-section of embryo older than that in fig. 17, showing monocot
character in lower part and dicot character in upper part; 3d, 4th, 6th, r4th,
Toth, and 24th sections.

Fic. 19. Cross-section of embryo showing equal cotyledonary lobes (dicot
characters); rst, 4th, 5th, 7th, 8th, and 15th sections.

IGS. 20-22. Castalia ampla.

Fic. 20. Embryo sac and two-celled embryo showing endosperm and nucellar
tube nucleus (ntn) in sac-like nucellar tube.

Fic. 21. Older stage of same, showing absorption of nucellar tube and
nucleus (nin) by endosperm.

Fic. 22. Spherical embryo with suspensor.

PLATE XVIII
Fics. 23-31. Castalia pubescens.
Fic. 23. Two-celled embryo and endosperm; the endosperm has penetrated
the upper part of the nucellar tube. es
Fic. 24. Spherical embryo with suspensor and endosperm, also showing
elongated nucellus cells in axis of ovule below sac (enc).
1G. 25. Older stages of the same showing enlargement of sac at right angles
to the original long axis.
1G. 26. Young pear-shaped embryo.
Fic. 27. Longitudinal section of embryo passing through middle of crescent-
shaped cotyledonary ridge («) and between the points of the same (y).

392 i BOTANICAL GAZETTE [NOVEMBER

G. 28. Longitudinal section at right angles to “a 27 passing through the
serie cia ridge (zz) near the points of the crescen
Fic. 29. Cross sections of embryo at about same age as figs. 27 and 28.
Fic. 30. Section d of fig. 29; cl, cotyledonary lobes; other letters same as
in figs. 27 and 28.
Fic. 31. Reconstruction from sections of embryo a little older than those
in figs. 27-30.
Fics. 32-40. Cabomba ED
Fic. 32. Two-celled embryo.
G. 33a. Section of embryo in octant stage showing two-celled suspensor.
Fi G. 336. Endosperm of 33a.
Fic. 34. Spherical embryo with three-celled suspensor.
G. 35. Spherical embryo showing original two-celled suspensor subdivided
by os divisions.
1G. 36. Longitudinal section of embryo at about time of origin of cotyle-
donary ridge, showing two-celled suspensor; cut same direction and showing
same points as fig. 27.
Fic. 37. Reconstruction from section of embryo slightly older than fig. 36
and showing early development of cotyledonary lobes.
1G. 38. Reconstruction from sections of almost mature embryo; drawn to’
same scale as fig. 37.
Fic. 39. Cross-sections of embryo; 2d, 6th, 8th, 12th, 24th, and 28th sections.
Fic. 40. Endosperm from embryo near same age or little older than jig. 38.

PLATE XVI

$s yn del

COOK on NYMPHAEACEAE

| BOTANICAL GAZETTE, XLII PLATE XVII

Expl serle Wat fad
Coase ola

(e]
eS)

ch

COOK on NYMPHAEACEAE

§ BOTANICAL GAZETTE, XLII PLATE: XVI

COOK on NYMPHAEACEAE

CURRENT LITERATURE.

BOOK REVIEWS.
Two new western ‘‘Floras.’’

Dr. RypsBerc has long been at work on a flora of the Rocky Mountain
tegion, and in connection with his studies there have been many new species
added and much critical work published. Therefore, when the Agricultural
Experiment Station of Colorado was compelled to complete the determinations
of its collections, it was natural to turn to Dr. RypBeErc, and the result is a station
bulletin dealing with the flora of Colorado. As was to be expected, the work
grew in the preparation, so that it is nearly an exhaustive list of the plants at
present known in Colorado. It is not a full descriptive manual in the ordinary
sense, for under the species one finds only synonymy, range, and stations; but
the analytical keys should enable one to determine the genus and species of all
the forms ordinarily met. In this way 2,912 species of vascular plants are char-
acterized, and this number is said to be surpassed by no state except California
and perhaps Florida. It is quite characteristic of this great flora that one-fifth
of it belongs to the Compositae, and that there are only twenty gymnosperms and
forty pteridophytes. The nomenclature used by the author is well known,
as are also his views on generic limitations. As he himself says in the introduc-
tion, he “belongs to that radical school which believes in small genera with closely
related species, rather than in larger ones with a heterogeneous mass of different
groups of plants having relatively little relationship to each other.” The author
also says that “the nomenclature used is in principle agreeing with the so-called
American code adopted at a meeting in Philadelphia, and submitted to the Inter-
national Botanical Congress at Vienna, with a few modifications resulting from a
compromise with the European botanists.” If this means that the Vienna Code
'S used only in so far as it meets the approval of the individual, then international
congresses on nomenclature will be of little value until they achieve the impossible
result of formulating a code that will satisfy all taxonomists. Very wisely the
author publishes in this bulletin no new genera or species, or even new Names Or
combinations. This publication will certainly serve a most useful purpose,
and both author and station are to be commended for carrying it through.

The other flora is that of Washington by CHARLES V. Preer’. The author
Says that his “principal aim is to present a summary of our present knowledge
Bitten

*Rypperc, P. A., Flora of Colorado. Agric. Exp. Sta. Colorado, Bull. roo.
PP. Xxli+4rq. 1906.

* Piper, CHARLES V., Flora of the State of Washington. Contrib. U. S. Nat.
Herb. 11: 1-637. pls. I-22 and colored map. 1906.

393

394 BOTANICAL GAZETTE [NOVEMBER

of the vascular plants of Washington and to call attention to the more important
problems, both taxonomic and ecological, which have become disclosed.” The
plan of the work is practically that of Dr. RyDBERG’s, namely a list of species with
synonymy, range, etc., but with simple keys for general identification. The
views as to the limitations of genera and species, however, are much more con-

rvative, the author making the rotted interesting remarks: “It is at least
é ubtful if the very large number of new names thus occasioned does not more
than counterbalance any advantage ose in favor of the practice. Certainly
the carrying of the practice to such an extreme that genera are considered to be
made up of species of similar habit, rather than to be based on structural char-
acter, seems inadvisable. Neither does it impress one as a valid argument that,
because in some extremely natural families the genera must perforce be based
on very slight differences, similar characters must be given equal consideration
in all families. _ The pages given to an account of the botanical explorers of

of the physiographic features of the flora. The “annotated catalogue” com-
prises a very long list of vascular plants, and it is interesting to note that 185
of them are endemic, two of the genera included in the list (Rainiera and Hes-
perogenia) being monotypic. The number of gymnosperms is almost exactly
that given above for Colorado, but the pteridophytes are more numerous, a list
of 64 being given—J. M. C

AN INTRODUCTION to plant physiology by the LinsBAvERs® is very welcome
and it is to be hoped that an English edition will be prepared. While too elab-
orate for our secondary schools at present, and yet too elementary for higher
students, the work contains a great deal that may be efficiently adapted to any
first course. The diction is semipopular. The first commendable feature
one notes is the logical arrangement of the topics. The ex riments (nearly
300) accompany the text, in fact are really a part of it. Following each chapter
is a series of problems for independent investigation, so that each chapter first

equips the student for independent work and then suggests that he do some as
indicated. The difficult topics of semipermeability, osmosis, etc., are skilfully
approached by preliminary experimentation with imbibition phenomena. Phys-
ical explanations involving such saree subjects as solution-tension are very
properly omitted. The treatment of some processes is far from modern.
combustion conception of respiration is 6 ealaed Photosynthesis is called
“assimilation” and contrasted with respiration, which is also given the name of
“dissimilation.” This is a very unfortunate confusion of both terms and ideas.
Of the seventy-eight cuts of the text proper, seven illustrate apparatus original
in design.—Raymonp H. Ponp.

3 — Lupwic, und LinsBavER, Karl, Borschule der Pflanzenhpysi-
ologie. Eine experimentale Einfiihrung in das Leben der Pflanzen. 8vo. Pp-—
figs. o Carl Konegen, Vienna. 1906.

es 2

1906] CURRENT LITERATURE 395

MINOR NOTICES.
Pflanzenfamilien.s—Part 226 contains the completion of the Neckeraceae
and the beginning of the Lembophylaceae by V. F. BRoTHERUS. secon
part of the second supplement has also appeared, including the literature of
1899-1904 in reference to dicotyledons up to the beginning of Euphorbiaceae.
oy: M. C,

NOTES EOR STUDENIs.

Archegoniatenstudien.—The tenth of GoEBEL’s series by this title is for size
almost a book in itself. It is made up of over twenty papers on morphology and
biology of mosses and liverworts, varying from a page or less, embodying a brief
note on the water adaptation in the form and position of the leaves in Ortho-
thynchium, to a paper of forty-odd pages on Dawsonia and its allies, and a like
one on marsupiferous Jungermanniales. In great part these papers were written
several years ago, and some of the researches have been epitomized in GOEBEL’s
Organographie, but they have not been published im extenso until now, on account
of other work.

Together they form a most important contribution to our knowledge of the
bryophytes—a contribution too full of details to report fully. At various places
It has a tinge of the polemic, for the author has to clear away many errors, and
he takes occasion to rebuke one and another for shortcomings. Much space is
devoted to speculations, which are confessedly unsupported by investigation

cause material or time was lacking. Such speculations, if put briefly, may
be Suggestive as a guide to future investigations; but they appear to be indulged
mas a basis for future claims to priority, if we may judge from some citations of
earlier ones in these pages. Even a scientific man is rarely without a prejudice
In favor of his own hypotheses. Thus the author guessed (Organographie 346)
about the development of the multicellular “spores” of Dicnemon: “Am wahr-
scheinlichsten ist es dass sich aus den gekeimten Sporen ein Fadenprotonema
bildet, etwa aus den Brutknospen von Tetraphis.” Now he declares ‘dass die
frither gedusserte Vermutung richtig war.” But the “protonemal filaments” func-
ton “der Hauptsache nach als Rhizoiden;” rhizoids arise also from the surface;
and the apical cell of the stem arises not as a branch of one of these “ protonema

“ments” but almost immediately from a marginal cell of the “spore.” It is
difficult to see how the earlier guess can possibly be justified by these observa-
tions. Certainly the resemblance to the behavior of the gemmae of Tetraphis is
tather remote. Other like instances might be cited; sometimes the guess was
Tight, sometimes not; and that is likely to be the case with these new ones. But
the observations are abundant, and the author’s keen discrimination and clear
Presentation throw light upon many obscure points.
Dawsonia is held to be the primitive form of the Polytrichum line by reason
Of the limited differentiation of tissues in the axis of the gametophyte, and espe-
ENGLER, A., und Prantt, K., Die natiirlichen Pflanzenfamilien. Lieferung

te
226. Leipzig: Wilhelm Engelmann. 1906.

396 BOTANICAL GAZETTE [NOVEMBER

cially on account of the structure of the peristome, whose development and
anatomy he clears up. He also points out the relations of the peristome of the
umiaceae and Tetraphideae to that of the Polytrichaceae.

Dicnemonaceae (Dicnemon and Mesotus) are recognized as a natural
group, characterized by the multicellular spores and the peculiar filamentous
outgrowths on the leaves. which are considered as organs of water absorption.
Both these characters and the structure of the sporophyte indicate adaptation for
alternating dry and wet periods.

Leptostomum has a peristome corresponding to a degenerate mniaceous
peristome. In Eriopus a fuller description is given of the leaves and of the
rhizoids at the base of the sporophyte than in Organographie 377.

The symmetry of the leaves and their position on the axis is discussed at some
length for the genera Pterygophyllum, Cyathophorum, Mittenia, Rhizogonium,
and Orthorhynchium, and there are minor notes on sundry points.

The development of the leaves of several species of Gottschea is shown to be
of the same type as in Fissidens; multicellular rhizoids are described and figured;
the absence of a perigone is correlated with the boring of the embryo sporophyte
deep into the stem; and G. splachnophylla shows a basal elaterophore like that of
Pelli

ia.

Paraphyllia were found in five genera, functioning in part for photosynthesis
and in part for holding water.

The “Geocalyceae” are described at length, and for them the more appro-
priate designation marsupiferous Jungermanniales is suggested. Three types
are discriminated: (a) Tylimanthus type (Tylimanthus, Marsupellopsis, Marsu-
pidium), with pouch originally solid and hollowed out by the growing embryo;
(b) Isotachis type, in which the archegonium after fertilization is surrounded by
a ring-like wall arising from the stem tissues, which carries up the leaves; (c) the
common type, with pouch arising after fertilization, hollow from the beginning
(Balantiopsis, Acrobolbus, Lethocolea). There are intermediate forms between
(a) and (c). In Acrobolbus there is even a “root-cap” on the pouch.

Another heterophyllous Radula, R. wvifera, is described, the so-called “slender
male spikes” of hepaticologists being here, as in R. pycnolejeunioides, composed
of small water sacs, frequently inhabited by animalcules; whereas the antheridia
are protected by quite different leaves. Hymenophyllum, with its slender “stalk”
and broader “leaf” shows no constancy in this differentiation, and since Pellia,
Preissia, Fegatella, etc., show similar forms on being grown in the dark and
then illuminated, the author is moved to conclude that “the stalk arises .
by autonomous etiolation”—a charming phrase which we owe to SACHS
nevertheless a phrase which is merely a wordy cloak for ignorance.

T imentary “leaves” of Blyttia xiphioides are organs of protection for
the apical region. The remarkable but inconstant water sacs of Metsger@
saccata arise, it is said, not by a lobing of the thallus, but by ‘‘an inrolling of eee
thallus margins from below and locally accelerated growth of isolated parts ~~
which latter sounds much like lobing in other words.

but

1906] CURRENT LITERATURE 307

The liverworts furnish most instructive examples of parallel structures, of
which the author cites many instances.—C. R. B.

Anaerobic respiration.—Inasmuch as PALLADIN and KostyTscHEW, work-
ing independently, had agreed, contrary to the conclusions of several other
observers, that anaerobic respiration was not identical with alcoholic fermenta-
tion, it seemed good to them to reinvestigate the question. They now finds
that while not identical in all plants and under all conditions, there are strikin
coincidences. For example, in living lupine seeds and seedlings they consider
the anaerobic respiration identical with alcoholic fermentation; but in frozen
lupine seedlings and stem tips of Vicia Faba the former has nothing to do with the
latter. In pea seeds and wheat embryos, living and frozen, there occurs a con-
siderable formation of alcohol, and the anaerobic respiration is “in great part”
alcoholic fermentation. They confirm the results of GODLEWSKI, STOCKLASA,
and others regarding the presence of “‘zymase,” but think it yet remains to be
shown that it is identical with yeast zymase. Under certain conditions aceton
and its allies are formed, both in aerobic and anaerobic respiration of living and
frozen plants.

It becomes more and more evident that the course of the respiratory decom-
position of the protoplasm may be varied.—C. R. B

Thermal death-point.—Mryer® has determined a formula by which may
be calculated the time necessary to kill bacteria at any given temperature, when
observation has determined the time necessary at any two convenient tempera-
tures, such as 80° and 100°, This rests upon the observation that the death
Periods form a geometrical paar ie 2 decreasing with the increasing tempera-

tures. Thus the formula is q= : , in which a is the first member of the

Progression, ¢ any other known member, g the progression, » the number of
terms. hes, Brau had determined the death period of Bacillus _subt subtilis at
Too® as inutes, and at 80° as 4500 minutes. Whence q=) F500 =0.2.
The is series then would be: 80°, 4500 minutes; 90°, goo minutes;
100°, 180 minutes; 110° , 36 minutes; 120°, 7.2 minutes; 130°, 1.4 minutes;
140°, 0.28 minutes or 17 ‘eo 150°, 3.4 seconds. The figures observed by
EYER agree well with these calculations. In practice this has an important
application in enabling one to calculate the supramaximal temperature, as
ENGELMANN called it, i. e., the time necessary to kill any form instantly—say in
-One second.—C, R. B.
Gi Stay Peerage eee
W., and KostytscuHew, S., Anaerobe Atmung, Alkoholgdrung
und Acton bei pe Samenpflanzen. Ber. Deutsch. Bot. Gessels. 24:273-
285.

f ste R, ARTHUR, Notiz iiber eine oe supramaximalen Tétungszeiten 4
ende Gabino Ber. Deutsch. Bot. Gesells. 24: 340-52. 1906.

398 BOTANICAL GAZEETT [NOVEMBER

Geotropic stimulation and position.—Czaprx? has replied to Firrine with
a paper which is largely a comparative study of the methods and results of the
workers in this problem. The author concedes to Firtrnc that in many cases
stronger stimulation occurs at go° than at 135°. On the other hand, FITTING’s
conclusion that 45° above the horizontal and 45° below are equivalent positions
is rejected. The reaction time is found to be practically the same at deviations
tween 20° and 160°, but is noticeably longer either above or below those
limits. The method of anti-ferment reaction shows that the stimulation is clearly
less at 45° below than at 45° above. In the inverse position there is no anti-
ferment reaction. Just how much significance is to be attributed to the results
of this method the reviewer cannot say. CzAPExK believes that in spite of all the
investigation of this problem a satisfactory solution is still in the future—Ray-
MOND H. Ponp.

Chemistry of germination ZatrsKr has studied certain changes that
occur in the proteids of germinating seeds and contributes these points. The
phosphorus-containing proteids and phosphatids (chiefly lecithin) are very quickly
and almost totally decomposed by an enzyme, with the formation of “inorganic”
phosphates, only 2 per cent. remaining unattacked. These bodies are apparently
nucleo-albumins (phytovitellins). What the enzyme is, whether trypsin or @
special one, remains to be investigated. The formation of asparagin, like the
proteid decomposition, is an enzymic process, proteolysis yielding material which
forms asparagin in an unknown way and independent of temperature changes,
at least in the later stages of germination. The nature of this process is to be
further studied by the author.°—C. R. B.

Absorption of solutes by soils.—Bulletin 32 of the Bureau of Soils'® is con-
sistent with the high standard established by the previous publications of the
Bureau. ScHREINER and Fartyer find as a general law in the case of phosphates
that the amount of solute a given soil will withdraw from solution percolating
through it is proportional to the quantity which the soil is still capable of absorb-
ing —RayMonp H. Ponp.

CZAPEK, FRIEDRICH, Die Wirkung verschiedener Neigungslagen auf den Geo-
tropismus Sees Organe. Jahrb. Wiss. Bot. 43:145-175- 1906-

8 ZALESKI, W., Uber die Rolle der Enzyme bei der Umwandlung oe
Beige: in keimenden Samen. Ber. Deutsch. Bot. Gesells. 24-2 85-
291. 1906.

9 , Zur Frage iiber den Einfluss der Temperatur auf die paar
setzung und Asparaginbildung der Samen wahrend der Keimung. Ber. nies?
Bot. Gesells. 24:292-5. 1906

These two titles are excellent examples of over-minuteness—a fault to be avoided
for the sake of those who have to cite the papers in future years. ee

10 SCHREINER, OSWALD, and FaILyER, GEORGE H., The absorption of pre
and potassium by soils. “Bureau of Soils, U. S. Department of Agriculture, Bull. 3
1906. ;

1906] CURRENT LITERATURE 399

Scion and stock.—By grafting Nicotiana Tabacum on N. affinis (which
contains little or no nicotin), and N. affinis on N. Tabacum, GRare and Lins-
BAUER have succeeded in showing,'* in a more convincing way than before,
the effect of the scion on the stock in respect to products of metabolism. Nicotin
was found abundantly in N. affimis, whether it was functioning as stock or scion.
Indeed, it attained almost the maximum amount found in N. Tabacum and
scarcely fell below the limits of variation in that species. When N. Tabacum
was the stock, and the scion, N. affinis was cut away completely, the new shoots
produced contained even less nicotin than the N. affinis leaves had; so that the
authors believe the scion had even increased the capacity of the N. Tabacum
stock to form this alkaloid. Further researches are in progress.—C. R. B

Tobacco.—In a long and somewhat controversial paper, excellently illus-
trated by fallen of various races of tobacco, ees 12 concludes that there
are four varieties within which may be grouped all the races of commerce.
Three of these, vv. nap ss. wrisilnada 8 virginica, are the offspring
of Nicotiana Tabacum, and one owes its origin to hybridization between N.
Tabacum and an unknown ai of Nicotiana. eg ANASTASIA is desirous of
securing seeds of certain races cultivated in the U.S. We bespeak the co-
Operation of those living in tobacco-raising sections. He may be addressed at
the Experiment Station, Scafati, Salerno, Italy.—C. R. B.

Phototropism.—Further proof that the epidermal cells of phototropic leaves
act as lenses, thus enabling them to function as receptive organs for adjustments
fo light, is adduced by HaBerLanpt*3. On covering young leaves of Begonia
Semperflorens with a layer of water, held in place by thin mica, he found no response
to oo light, though control leaves had attained the usual transverse posture,

the water-covered leaves gained it, though not perfectly, after removal of
a oust of water.—C. R. B.

MOND

Nicos G , V., and Linssaver, K., Uber die wechselseitige Beeinflussung
icottana Tsbasins und WN. afinis bei der Pfropfung. Ber. Deutsch. Bot. Gesells.
1906.

1 ANASTASIA o, Le variet& typiche — Nicotiana Tabacum L. R.
Istituto Sperimentale Tabacchi in Scafati. Ministero delle Finanze. Imp. 8vo.
PP. 122. figs. and plates 31. 1906

LANDT, G., Ein experinientelie Beweis fiir die Bedeutung der papillosen
Laubblatepiderms als Lichtsinnesorgan. ge . Deutsch, Bot. Gesells. 24:361-6.

13

] *4 BREAZE EALE, ne F., The relation of sodium oO potassium in soil and solution
Sutures. Journ. Amer. Chem. Soc. 37: pages 1906.

NEWS.

DurRING 1905 Kew Herbarium received in gifts over 16,000 sheets from
about one hundred persons and institutions, and purchased nearly 7,000 sheets.

RaymonD H. Ponp, Northwestern University, has been awarded a research
scholarship at the New York Botanical Garden for six months, beginning on
October 1.

THE BOTANICAL DEPARTMENT of the Universitv of Illinois has purchased the
herbarium of GEorce D. McDona tp, of Peoria, Ill. It contains about 12,000
specimens.— Science.

VERNON H. BLACKMAN, for ten years in the Department of Botany of the
British Museum, has resigned this position to become Lecturer in Botany at
the Birkbeck Institute. He also holds a lectureship at the East London College.

In Botanisches Centralblatt (102 : 367. 1906) there is published a short
biographical sketch of the late Professor H. MARSHALL Warp, prepared by
Professor S. H. Vives; and another notice appears in the Kew Bulletin (1906:
281), by L. A. Boonie.

AN APPRECIATIVE NOTICE of the life and work of the late C. B. CLARKE
appears in Bulletin de l’ Herbier for September 1906, prepared by CASIMIR Dee
CANDOLLE. Another biographical sketch of CLARKE, unsigned and including
bibliography, is published in Kew Bulletin (1906: 271-281).

In Journal oj Botany for October 1906 there appears a biographical sketch
of WiLt1AM Mirren, the bryologist, prepared by W. B. Hemstey, and accom-
panied by an excellent portrait. He died July 27, 1906, in his eighty-seventh
year. The same number also contains a portrait of RoBERT BROWN. Another
sketch of Mirren by Helmsley is published in Kew Bulletin (1906: 283).

A GENERAL ACCOUNT of the work of Section K at the York meeting of the
British Association is published in Nature of October 4. There were three
appointed discussions upon the following topics: Some aspects of the present
position of paleozoic botany, opened by D. H. Scorr; The nature of fertilization,
opened by V. H. Backman; The phylogenetic value of the vascular structure 0
seedlings, papers being read by a number of botanists whose names are identified
with this phase of work. .- : —

WITH THE first part of volume 96, issued late in March, the publication ©
Flora passed into the hands of the well-known house of Gustav F ISCHER. Here-
after the volumes will be enlarged to at least 560 pages, without increase In price,
and the designation of Erganzungsbande will be abandoned. Fortunately they
were always numbered consecutively with the others, and so the superfluous
~ name made little bibliographic confusion. No reviews of literature are to appear
in future. Articles are to be restricted in length as a rule to 48 pages, and for
this the editor clears his desk by getting in the tenth of his Archegoniatenstudien
as the leader of the new volume, a paper of over 200 pages!

400

ee

THE

B0TANICAL GAZETTE

December 1906

Editors: JOHN M. COULTER and CHARLES R. BARNES

CONTENTS

Shigeo Yamanouchi

The Life-History of Polysiphonia
The Morphology of the Ascocarp and Spore Formation in the

Many-Spored Asci of Thecotheus Pelletieri
James Bertram Overton

Current Literature

News

The University of Chicago Press
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The Botanical Gazette

H Monthly Journal Lmbracing all Departments of Botanical Science

‘dited by JoHN M. CouLTER and CHARLEs R. S, with the rae et of other members of the
botanical staff of ‘_ iavesies of Chic

rl XLII, No. 6 Issued December 22, 1906

CONTENTS

HE LIFE-HISTORY OF price igs se CONTRIBUTIONS FROM THE HULL BOTANI-
CAL LABORATORY, XXVII gs a THREE DIAGRAMS AND PLATES i
Shigeo Yamanouchi - - - 401

"HE eo eed OF THE ASCOCARP AND SPORE FORMATION IN THE MANY-
ASCI OF THECOTHEUS PELLETIERI oF 3 PLATES ere
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VOLUME XLII NUMBER 6

DOTANICAL. Greaeel ee

DECEMBER 1906

THE LIFE HISTORY OF POLYSIPHONIA VIOLACEA.
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY.
LXXXVI.

SHIGEO YAMANOUCHI.
(WITH THREE DIAGRAMS AND PLATES XIX—XXVIII)
INTRODUCTION.

THERE have been published by various authors many accounts
of investigations on the red algae treating of the morphology of the
thallus, the development of the cystocarp, and tetraspore formation.
The first general studies on the reproductive processes in the group
were those of BoRNET and THURET (12) and JANCZEWSKI (43). These
papers have never been surpassed in clearness of expression and
beauty of illustration, but they considered simply the outer mor-
phology or histology and gave no cytological details of fertilization,
nor did they trace the life history. ScHmitz (69) published an
account of the fructifications of more than forty species in various
groups of the red algae, giving special attention to the auxiliary
cells, but in his conclusions he failed to distinguish between the act
of fertilization and the secondary fusions concerned with the auxiliary
cells, and he developed elaborate speculations in which these fusions
Were included as a part of the sexual process. This misconception
was cleared up by OrtmManns’ discovery (55) that the real sexual act
is the union of male and female gamete nuclei in the carpogonium,
and that the auxiliary cells are probably only concerned with the
nourishment of the cystocarp. OLTMANNS. was the first author to
develop the theory that the structure derived from the fertilized carpo-
gonium was sporophytic in character; however, he presented no

401

402 BOTANICAL GAZETTE [DECEMBER

cytological evidence for this view. Wotre (86) placed this theory
of OLTMANNS on a cytological basis by showing that the cystocarp
of Nemalion contained nuclei with double the number of chromosomes
found in the sexual plants or gametophytes. However, WoLre did
not give a detailed account of the period of chromosome reduction.
Nemalion is one of the simplest types of the red algae. ‘There are no
auxiliary cells or tetraspores, at least on the American plants so far
as known; consequently the life history is very much simpler than
that of the higher forms. The behavior of the auxiliary cell nucleus
during the development of the cystocarp has been studied by OLt-
MANNS (55) with especial clearness in Callithamnion and Dudresnaya,
but the structural difference between the nuclei of auxiliary cells
(gametophytic) and those derived from the fertilized carpogonium
(sporophytic) was not determined by him. Moreover, as regards the
real nature of the tetraspore, so characteristic of the red algae, there
has been no cytological work except a study of nuclear division in
Corallina by Davis (18).

The significance of the tetraspore in the life history was not
known. Various authors have presented speculations upon the
subject; for example, OLTMANNS (55) regarded the tetraspore as
an asexual reproductive structure comparable to brood organs or
gemmae, having no fixed place in the life cycle, and STRASBURGER
has followed this interpretation.

This investigation was begun in the hope that some of these problems
might be solved by carefully following the life history of a type with
particular attention to the behavior of the nucleus at critical periods.
Although red algae include a wide range of types, the nature of the
tetraspore and the history of the life cycle where tetraspores are present
have probably been determined by this investigation of the ontogeny.
of Polysiphonia violacea Grev., except in forms where abnormalities
may be present, due perhaps to apogamy or apospory.

As stated in a preliminary paper (YAMANoUCHI 87), the material
was collected at Woods Hole, Mass., during July and August 1995,
where cultures of the carpospores and tetraspores were made to
obtain stages in their germination. The method of killing, fixing,
imbedding, cutting, and staining are given in that preliminary note.

This paper presents first the results of my studies of the mitosis in

ee DS ee De Eee See

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 403

germinating tetraspores and carpospores and in the vegetative cells
of mature plants; then comes an account of spermatogenesis, forma-
tion of procarp, fertilization, and development of the cystocarp;
tetraspore formation is then considered, followed’ by a description of
certain abnormalities; finally, there is a discussion of the cytological

phenomena and alternation of generations. This last topic has been

given considerable attention, for the chief results of this investigation
have been the establishment of an antithetic alternation of generations
in Polysiphonia, with the period of chromosome reduction at the
time of tetraspore formation.

The investigation was begun during the summer of 1905 at the
suggestion of Dr. BrapLey M. Davis during my stay as an occupant
of a Carnegie research table at the Marine Biological Laboratory,
Woods Hole; and to the Carnegie Institution I wish to express my
obligations for the privilege of the table. The studies were con-
tinued and completed by me in the Hull Botanical Laboratory as a
Fellow of The University of Chicago, under the direction of Professor
Joun M. Courter and Dr. Cuartes J. CHAMBERLAIN, the kind
assistance and painstaking criticism of Dr. Davis continuing also
throughout the whole progress of the investigation. To these gentle-
men I am under great obligation; and also to the other members of
the botanical staff of Hull Botanical Laboratory for courtesies extended
to me in many ways.

THE FIRST MITOSIS IN THE GERMINATING TETRASPORE.

The tetraspore when discharged from the parent plant assumes
a spherical form. Plastids usually lie near the periphery of the cell,
Whose cytoplasm presents an irregular, coarse alveolar structure, with
the nucleus lying near the center. The cytoplasm surrounding the
nuclear membrane is a finer network than anywhere else in the cell.
Within the nucleus there is a very delicate linin mesh dotted here and
there with chromatic granules (fig. 1). From the fact that the trans-
vetse walls of the cytoplasmic alveoli end on the nuclear membrane at
points where the linin threads start, it seems possible that there exists
a close physiological relation between these structures. The nucleus
8enerally contains a single nucleolus, variously situated and homo-
8eneous in structure, but sometimes two nucleoli are present.

404 BOTANICAL GAZETTE . [DECEMBER

Preliminary to mitosis, the delicate network becomes some-
what coarser and the thread somewhat broader, and gradually in
many different parts the chromatin granules appear in irregular
rows as chains of beads of different lengths. There are about 20
of these chains, as illustrated in jigs. 2a—2c, which represent three
sections of the same nucleus. They are the beginnings of the chromo-
somes, similar to the prochromosomes described by Overton (58)
in the presynaptic stage in the pollen mother cells of Thalictrum and
three other species of flowering plants. The material which accumu-
lates in these prochromosomes must come from the chromatin gran-
ules imbedded in the linin thread, for it is evident that the nucleolus
does not contribute any material directly to their formation. This
behavior is therefore similar to the process of chromosome formation
in higher plants, and is very different from the condition reported by
Wo tre (86) for Nemalion, where the chromosomes are described as
coming out from the nucleolus. The nucleolus of Polysiphonia
remains unchanged while the prochromosomes are being formed.
These prochromosomes gradually become more pronounced, increase
in breadth, and the bead-like structure is transformed into the more
homogeneous rod-shaped chromosomes that become distributed
through the whole nuclear cavity attached to a linin thread, as shown
in figs. 3a and 3b, which represent two sections of the same nucleus.
The nucleolus may remain undivided or fragment into two at this time.

The cytoplasm around the resting nuclear membrane appears at
first homogeneous, but during prophase there is a gradual accumu-
lation on the two opposite sides of the nucleus, and finally two deeply
staining centrosome-like bodies appear, forming the poles of the more
slightly elongated nucleus (fig. 4). While these changes in the cyto-
plasm are going on without the nucleus, some important events take
place within. The chromosomes become thickened and more com-
pact and gather in the middle region of the nuclear cavity, with linin
threads still attached to their ends, and at last they are arranged in
the equatorial plate (fig. 5). The nuclear membrane is still present
when the spindle is developed (jig. 5), so that the latter is conse-
quently intranuclear.

It is very interesting to compare this stage with the previous one
(fig. 4), taking into consideration the kinoplasmic centers, the shape

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 405

of the nuclear cavity, and the spindle. As regards the centers of
kinoplasmic activity, in the preceding stage the kinoplasm is shown
in the process of accumulation at the two poles, and a single clearly
differentiated granule may be interpreted as the first visible indication
of approaching spindle formation. At the time when the equatorial
plate is formed, the kinoplasmic material becomes massed more
densely than before, and two very large centrosphere-like structures
are differentiated at the poles of the spindle (jigs. 5,6). These
kinoplasmic bodies have a compact, well-defined form, but are with-
out radiation. The nuclear cavity at the stage of metaphase is
smaller than before, and the poles of the spindle become drawn
closer together. The development of the spindle proved very
difficult to study, and its history is discussed later in the paper under
the head of spindle formation.

The accumulations of kinoplasm at the poles of the spindle are
very characteristic and resemble the centrospheres described by
Davis (18) in the tetraspore mother cell of Corallina, except that
the latter have well-defined radiations. The chromosomes when
arranged in the equatorial plate are readily counted if viewed in trans-
verse sections of the spindle (fig. 7), as well as during prophase
(figs. 3a, 3b), and the number is clearly 20. Granular fragments of
the nucleolus are always present in the nuclear cavity during the
metaphase, after which they disappear.

The duration of metaphase is rather long and the centrosphere-
like Structures persist until late anaphase. When each group of
daughter chromosomes passes to the pole of the spindle, there are left
only a few fibrils forming a central spindle between them (fig. 8).
After anaphase the kinoplasm intrudes into the nuclear cavity and
the central spindle gradually disappears (fig. 9). The kinoplasm
thus surrounds the groups of daughter chromosomes, and the centro-
Sphere-like structure loses its distinct differentiation and becomes
‘ cloudy mass of kinoplasm without a clearly defined boundary
(fig. 9).

Each group of daughter chromosomes, which during anaphase
had a flattened form, becomes more or less spherical, with a small
Space within (fig. 10). The mass of chromosomes surrounded by
Stanular kinoplasm comes to lie in nuclear sap or caryolymph, and

406 BOTANICAL GAZETTE [DECEMBER

it seems possible that the nuclear membrane may be formed as the
result of the contact of the caryolymph with the surrounding cyto-
plasm (fig. rz). Such conclusions were drawn by Lawson (44) and
‘GrécorrE and WycGaeErts (36) in their studies of the telophase of
mitosis. The chromosomes later lose their individual outlines and
the mass becomes transformed into a chromatin network (fig. 12).
A new nucleolus is then formed in the daughter nucleus.

No mention has yet been made of the manner of cell division. The
coarse alveolar structure of the cytoplasm taken as a whole persists
during mitosis, the kinoplasm associated with the division of the
nucleus remaining distinct from the alveolar cytoplasm and reacting
more deeply to the plasma stains. The daughter nuclei when formed
lie above one another in the germinating tetraspore. Before they
have attained their full size a cleavage furrow appears at the middle
region of the cell which is at first very shallow. The central spindle
that lay between the two groups of daughter chromosomes has entirely
disappeared before the cleavage furrow is formed, so that the center
of the cell is filled by cytoplasm which presents a very coarse alveolar
structure, especially in the middle region, where the cleavage furrow
begins (fig. 13). This furrow proceeds inward, the only visible assis-
tance in its development being the extensive fusion of vacuoles by
the breaking of their limiting membranes so that less resistance is
presented to its progress. Finally, the furrow reaches nearly to the
center of the cell (fig. 14), so that the tetraspore becomes divided
into daughter cells, which are in communication by a strand of
protoplasm, as is so generally characteristic of the red algae.

THE FIRST MITOSIS IN THE GERMINATING CARPOSPORE.

The carpospore on its escape from the cystocarp is somewhat
pear-shaped, but it gradually assumes an oblong or spherical form
while floating in the water. The coarse alveolar structure of the
cytoplasm, the arrangement of the plastids, and the fine linin net-
work within the nucleus (fig. 15) are similar to those of the tetraspore-
Moreover, the first mitosis takes place at about the same period after
their escape from parent plants, namely after about fifteen hours.

The history of the mitosis in the germinating carpospore is S0

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 407

similar to that in the tetraspore that it seems best to point out only
the marked differences between the two. The delicate linin network
within the nucleus passes into a coarse chromatin reticulum upon
which chains of chromatin granules appear here and there (figs. 16a—-
16c), and these are prochtomosomes, as illustrated in the preceding
figures of the tetraspore (figs. 2a-2c). The number of prochromo-
somes, however, is 40, and consequently double the number in the
germinating tetraspore. The 4o prochromosomes grow more and
more homogeneous in structure and finally become elongated chromo-
somes (jigs. 17a, 176). The weakly staining linin network disappears,
but short threads remain attached at the ends of chromosomes.
The kinoplasm surrounding the nuclear membrane becomes accumu-
lated at the two poles of the nucleus, where a centrosome-like body
may always be found (jig. 18a), and this accumulation of kinoplasm
proceeds still further until there are two conspicuous centrosphere-
like structures differentiated at metaphase (fig. 19). The spindle
is somewhat larger and broader than that in the tetraspore, because
of the double number of chromosomes (fig. 19). The polar view of
that stage (fig. 20) clearly shows the number 4o.

The nucleolus fragments during metaphase, the portions lying
beside the spindle (ig. 19) and sometimes remaining until anaphase,
after which they disappear. The behavior of the daughter chromo-
somes after anaphase is the same as during mitosis in the tetraspore;
the groups of daughter chromosomes gather at the poles of the spindle
(fig. 21) and become surrounded by granular kinoplasm (fig. 22).
At the time of the formation of the nuclear membrane, the chromo-
Somes may still be recognized and estimated as 40 (figs. 234, 23b).
The daughter nuclei increase in size by the secretion of nuclear sap
(figs. 24a-24¢), and finally the chromatin becomes distributed over a
linin network in the resting nucleus (fig. 25). The germinating carpo-
Spore becomes divided by a cleavage furrow in a similar manner to
that of the tetraspore.

The second and third mitosis in both germinating tetraspore and
Carpospore were also studied, and they were similar to those of the
first divisions, showing always the two essential differences in the
number of chromosomes.

408 BOTANICAL GAZETTE [DECEMBER

MITOSIS IN THE VEGETATIVE CELLS OF THE MALE, FEMALE, AND
TETRASPORIC PLANTS.

To make sure of the number of chromosomes contained within
the nuclei throughout the life history, the mitoses in vegetative cells
of the three forms of Polysiphonia plants—male, female, and tetra-
sporic—were studied. The following is a very brief account of the
essential features of these mitoses.

The nuclei in the apical cells of any of the three forms of plants
are somewhat larger in size than those in older region of the thallus;
but although it is not difficult to obtain the successive stages of mitosis
in older parts, the nucleus of the apical cell is somewhat more favor-
able for study and will be used in this description.

The cytoplasm in the apical cell shows very fine alveolar structure,
the plastids lie near the wall, and the nucleus in the resting stage
resembles that in the germinating carpospore and tetraspore (jigs. 26,
45). The linin network becomes coarser (figs. 27, 46), and finally
in the case of the male (figs. 28, 29) and female plants (fig. 36) 20
chromosomes appear, whereas in the tetrasporic plant (fig. 47) 4°
chromosomes are present. The chromosomes may be readily counted
at metaphase in polar views of equatorial plates, when it is evident
that the sexual plants have 20 (figs. 31, 38) and the tetrasporic plants
40 (fig. 50). In spite of the small size of the nuclei, kinoplasmic
accumulations at opposite poles of the nucleus are evident during
prophase, and deeply staining centrosome-like bodies are conspicuous
at the poles just before the spindle is formed (figs. 29, 36). Centro-
sphere-like structures are very conspicuous at the poles of the spindle
during metaphase (jigs. 30, 37, 48). These structures are more
clearly shown in the mitosis in older regions of the thallus. Fig. 43
illustrates such a mitosis from a female plant, those of the male and
tetrasporic plants being omitted to avoid repetition. The smaller size
of the nuclear cavity during metaphase is as constant a character of
these mitoses as of those in the tetraspores and carpospores. After
metaphase the two sets of daughter chromosomes remain included
in the old nuclear membrane for a while (figs. 32, 39, 49)- During
the anaphase the groups become further separated, the nuclear
membrane disappears, and a large vacuole intrudes between them
(figs. 33, 41, 51). When the daughter nuclei are completely formed,
a cleavage furrow develops at the periphery"in the middle region ©

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 409

the cell (figs. 35, 42), a large vacuole being present in the center. The
mechanism of constriction by the cleavage furrow is probably greatly
assisted by the presence of this single vacuole, in place of numbers
of smaller ones which are found in the tetraspores and carpospores.

SPERMATOGENESIS.

The sperms or spermatia are formed normally on special short
branches called antheridia, which are developed in clusters at the
tips of the main filaments. The
antheridium consists of an axial
siphon (diagram 1) which becomes
surrounded and covered by a large
number of small cells. These
generally develop sperm mother
cells at the periphery of the anthe-
tidium, and may consequently be
called “stalk cells.’ The mitoses
in the axial siphon of the anthe-
tidium were studied (fig. 52), as
well as those which form the stalk
cells (fig. 53), and they showed
the number of chromosomes to be
20. The methods of chromosome
formation, the development of the
Mtranuclear spindle, and the cell
division by constriction are the
Same as those of the vegetative cells
already described.

h . DIAGRAM 1.—Section of an anthe-
€ formation of the Sperm jidium, showing position of axial

mother cells from the stalk cells _ siphon, stalk cell (sc), sperm mother
(fig. 54) is illustrated in jigs. 55-61. cell (sme), and development of the

‘8. 55 presents the prophase of “P°™ 28

of the mitosis, fig. 56 metaphase, fig. 57 the equatorial plate viewed
from a pole, fig. 58 shows anaphase, and jigs. 59 and 6o illustrate
telophase. The cell division by constriction is shown in jig. 61:

he Sperm mother cell (fig. 62) increases in size and assumes its
characteristic form, which is narrow at the periphery and swollen at
the base. In rare cases the formation of the stalk cell is omitted,

410 BOTANICAL GAZETTE [DECEMBER

so that sperm mother cells are developed directly from the axial
siphon of the antheridium.

The cytoplasm of the sperm mother cell (fig. 62) has a very delicate
granular structure and is generally destitute of plastids. The nucleus
in the resting state contains a fine network and a nucleolus. Pro-
chromosomes, 20 in number, are formed in the network (jigs. 63, 634)
and are connected by weakly staining linin threads. The prochromo-
somes increase in size and become rod-shaped chromosomes (jigs.
64, 64a). :

Kinoplasm becomes differentiated from the surrounding cyto-
plasm and accumulates at the poles of the elongating nucleus, and a
centrosome-like body appears at each pole (figs. 64, 64a). The
stage of prophase passes into metaphase (jigs. 65, 65a), when centro-
sphere-like structures are well-developed and the axis of the spindle
is shorter than the diameter of the equatorial plate, as is the case
during the mitoses within the carpospores, tetraspores, and vegetative
cells. The number of chromosomes is clearly 20 in this mitosis, as
shown in polar view of the equatorial plate (fig. 66). The nuclear
membrane is present during metaphase (fig. 67), and as the two
groups of daughter chromosomes separate a vacuole intrudes between
them (figs. 68, 69, 70). The centrosphere-like structures are not
recognizable after metaphase. The set of daughter chromosomes
which passes to the basal region of the cell becomes aggregated,
surrounded by a nuclear membrane, and enters into a resting condi-
tion; while the chromosomes of the other set, passing to the upper
part of the cell still retain their individuality, although it is probable
that a very delicate membrane may be formed (fig. 70).

A cleavage furrow in the middle region of the cells appears (fig. 72)s
and by the same mechanism as in the case of vegetative cells effects
a separation of the upper half as a sperm cell from the lower half.
The greater part of the large vacuole is included in the sperm, which
consequently has a relatively small amount of protoplasm in com-
parison with its size (figs. 72, 73). The cleavage furrow which cuts off
the sperm cell crosses the sperm mother cell obliquely, and conse-
quently the sperm assumes a lateral position, allowing the sperm
mother cell to elongate. When the matured sperm is detached esse
pletely from the sperm mother cell, the latter has assumed again Its
characteristic extended form (fig. 75).

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 4II

The sperm when detached is oval in form (fig. 73), and has a thin
wall derived from the mother cell, and a large vacuole occupies almost
all the cell cavity. The cytoplasm is therefore forced to lie in a thin
layer under the cell wall, and the nucleus occupies the larger end of
the oval. The chromosomes maintain their individuality and are
connected with one another by delicate linin threads (jigs. 74, 74a).

The nucleus remaining in the sperm mother cell after the formation
of the first sperm divides at once, passing through prophase (jig. 75),
metaphase (jigs. 76, 78), and anaphase stages (jigs. 79, 80), following
the same history as in the previous mitoses. Here is apparent also
the same conspicuous difference in the form of the nucleus between
prophase and metaphase (figs. 75, 76), 20 chromosomes (fig. 77)
always appearing in this critical stage. Finally, the telophase of
Mitosis is followed by cell division through a cleavage furrow, which
cuts off the second sperm (fig. 8r) in a similar manner to the first.
The nucleus which remains in the sperm mother cell may repeat the
Process, forming a third sperm.

The successive formation of sperms by constriction from the sperm
mother cell may be compared, in a general way at least, to the pro-
cess of formation of conidia in certain groups of fungi, where the
conidia are developed successively by constriction from a conidiophore.
Of course such a comparison is a superficial one, since conidia are

Y NO means comparable to sperms in the phylogenetic sense. The
Spermatia found in the rusts and lichens, and certain antheridia of
the Laboulbeniaceae present greater resemblances. THAXTER (78)
describes an exogenous method of sperm formation in Ceratomyces
and Zodiomyces, in which sperms are developed successively from a
definite point at the distal end of fertile cells of the antheridial branches,
agreeing thus with the process in Polysiphonia.

Wotre (86) considers the sperm of Nemalion to be the homologue
of an antheridium because the sperm nucleus divides into two. No
Mitosis was found in the sperm of Polysiphonia, although this
Matter received careful attention. The sperm of Nemalion also
“scapes as a naked or thin-walled protoplast from the parent cell-
‘Membrane, while that of Polysiphonia becomes detached and retains
the parent cell wall. The differences, however, do not seem to the
author to affect the relationship of these two sperms as homologous
Sttuctures. That of Polysiphonia is also the homologue of a uni-

412 BOTANICAL GAZETTE [DECEMBER

cellular antheridium, in which mitosis, if ever present, has been sup-
pressed, and the cell as a unit has become the male sexual element.
FORMATION OF THE PROCARP.

Development of the carpogonial branch.—The female organ or
procarp consists in the beginning of a short branch of three or four
cells. The most important of these is a cell of the axial siphon which
lies next to the apical cell (diagram 2, A). This cell increases in size
more rapidly than do the adjacent cells of the filament, so that it is
very easy to recognize the primordium of the female organ, and
divides successively to form five peripheral cells, which finally com-

B E

DIAGRAM 2.—Development of the carpogonial branch: A, young procarp with
pericentral cell (pc); B, cross section of A; C, formation of first cell of carpogonial
branch; D, the four cells of carpogonial branch; E, development of trichogyne (tr)
from fourth cell or carpogonium (carp) of the carpogonial branch.
pletely surround it (diagram 2, B). The first stage is illustrated in
figs. 82-84 and the second in figs. 85-87. The third and fourth
divisions of the siphon cell have not been figured, but they occur in
such a manner that the third and fourth peripheral cells are formed
opposite each other and between the first and second (diagram 2, B).
The fifth division gives rise to a peripheral cell between the first and
the fourth, which later develops the carpogonial branch and has been
called the pericentral cell.

During every nuclear division concerned with the formation of
the peripheral cells, 20 chromosomes constantly appear, as shown in
polar views (jigs. 83, 86), and this number is passed over to the peri-
central cell. The nucleus in the pericentral cell divides in a direction
nearly parallel to the axis of the procarp (figs. 89-93), cutting off a
cell which develops the carpogonial branch (diagram 2, C). ene

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 413

pericentral cell later also gives rise to a group of auxiliary cells. The
carpogonial branch consists of four cells which are formed successively
as shown in diagram 2, D, E. It is somewhat bent, so that the ter-
minal cell lies almost above the pericentral cell. This terminal cell
becomes the carpogonium and develops the trichogyne. The mitoses
concerned with the development of the carpogonial branch are illus-
trated in figs. 94-99, and invariably showed 20 chromosomes at
metaphase. As the result of these successive mitoses, the carpogonial
branch extends at one side of the central axial cell, with the pericentral
cell situated between them (diagram 2, E).

The nucleus in the fourth or terminal cell of the carpogonial
branch divides (fig. roo) to form two nuclei (fig. roz), each with 20
chromosomes, one of which becomes the female gamete nucleus,
while the other enters the trichogyne that is formed at once. The
upper end of the cell pushes out as a delicate process which contains
almost from the beginning one of the two nuclei, the other remain-
ing in the basal swollen region of the cell called the carpogonium
(figs. 102, 10 3, 104), which corresponds to an oogonium. The forma-
tion of the trichogyne completes the development of the female organ,
Whose parts in longitudinal section are shown in jig. 103.

The trichogyne.—The trichogyne nucleus, as a rule, is situated in
the middle region of the trichogyne, which has about the same breadth
throughout its tubular cavity, but becomes constricted below where
it joins the carpogonium. No plastids could be found in the trichogyne.

The presence of a trichogyne nucleus in the red algae has been a
subject of some controversy. Scumitz (69) described a large single
or several small granular bodies, which stained like chromatin, in
the trichogyne of Batrachos permum monilijorme and Gloeosiphonia
before fertilization, but he gives no interpretation further than the
few words, “Derivate des Zellkerns der weiblichen Zellen?” Eight
years later Davis (17) observed in the same species of Batracho-
‘permum an unmistakable nucleus-in the trichogyne, staining with
haematoxylin as a dark blue body. OLTMANNS (55) also observed
the granule within the trichogyne of Gloeosiphonia, but he regarded it
as having no connection with the nucleus. ScHMrpLE (68) failed
to find the nucleus in the trichogyne of Batrachospermum, and
OstERHOUT (57) contends that it is not present. Wotre (86)

414 BOTANICAL GAZETTE [DECEMBER

observed a nucleus in the trichogyne of Nemalion, which he assumes
to be derived from the young carpogonium, although the mitotic
figure was not found. The presence of a nucleus in the trichogyne
necessitates a modification of our conception of the morphology of
the female organ in the red algae.

The earlier conception of the morphology of the trichogyne as
given by Scumitz (69) was a cytoplasmic extension of the carpo-
gonium, developed as the receptive organ for the sperm. This
conception was followed by OxtMaNNs (55), SCHMIDLE (68),
and OsterHout (57). Davis (17), however, concluded that the
trichogyne is not a cytoplasmic extension from the carpogonium, but
that it possesses a well-defined nucleus and hence has a certain degree
of independence. The trichogyne of Batrachospermum has certainly
a body that must be regarded as a chromatophore. Wo rer’s studies
of Nemalion (86) support this view with respect to a trichogyne
nucleus. In Polysiphonia, as stated above, there is present a tricho-
gyne nucleus whose origin has been traced to a division in the terminal
cell of the carpogonial branch. These facts have an important bear-
ing on the structure of the trichogyne in lichens and Laboulbeniaceae.
THAXTER (78) has described multicellular branching trichogynes
in certain forms of Laboulbeniaceae, and the long multicellular
trichogyne of Collema (BavEeR 6) and Physcia (DARBISHTRE 162)
illustrate similar conditions. In the lower forms of algae where
heterogamy is established, male and female gametes are generally
formed in unicellular antheridia and oogonia. The female gametes
having become non-motile, usually remain within the cogonium and
are fertilized by motile male gametes which enter the oogonium
through a pore, as is illustrated by Oedogonium. With the loss of
motility on the part of the male gametes, a receptive region or structure
seems to have been developed by the oogonium, and in this manner
the trichogyne probably arose. However, the development of the
trichogyne means that the female cell, which is the homologue of an
oogonium, acts as a unit. Should there be in such a cell one or more
mitoses, which are the remnants of ancient nuclear division when two
or more gametes may have been developed, then the supernumerary
nuclei would be expected to degenerate. This seems to be the con-
dition in the red algae, where there is an extra nucleus beside the one

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 415

which is in the gamete. This extra nucleus has an important relation
to the development of the trichogyne, which consequently is much
more than a mere cytoplasmic extension from the carpogonium; for
having a nucleus it may possess the possibilities of a somewhat exten-
sive development. This is perhaps the explanation of the multi-
cellular trichogynes of the lichens and the Laboulbeniaceae, which
in some forms of the latter group are extensively branched.

The passage of the sperm nucleus through the trichogyne into the
car pogonium.—The nucleus of the carpogonium increases in size as
the female cell matures, while the nucleus of the trichogyne remains
about the same size as when it was formed (fig. 104). The sperm
becomes attached to the tip of trichogyne (fig. 105). The walls
between the two structures dissolve, and the contents of the sperm
flows into the trichogyne (jig. 106). The sperm nucleus consists of a
number of deeply staining bodies (about 20), which are chromosomes.
The nuclear membrane if present must be very delicate, for it could
not be positively recognized (figs. 106-108). The deeply staining
‘petm nucleus in the trichogyne is in sharp contrast with the smaller
trichogyne nucleus whose chromatin content stains weakly. The
sperm nucleus moves downward, passing the trichogyne nucleus (jigs.
707, 108), and enters the carpogonium. The female nucleus in the
“atpogonium, which until this time lay at the bottom of the cell,
seems to move upward a short distance as if to meet the sperm nucleus
(fig. 109a). The two gamete nuclei are strikingly dissimilar at the
time of union, the male consisting of a densely packed aggregation of
chromosomes, while the female is larger and in a typical resting
Condition, with chromatin distributed over a linin network (fig. r09a).

he trichogyne nucleus may still be recognized after the sperm
nucleus has passed into the carpogonium. However, the cytoplasm of
the trichogyne soon shows signs of disorganization, first at the tip,
and a little later the trichogyne nucleus breaks down. When the
male nucleus is in contact with the female and becomes somewhat
Pressed against it, the cytoplasm of the trichogyne has probably
always separated from the carpogonium and the trichogyne has begun
to shrivel],

Formation of the auxiliary cells Parallel with the fusion of the
8amete nuclei there takes place the development of a set of auxiliary

416 BOTANICAL GAZETTE [DECEMBER

cells, as shown in diagram 3. The pericentral cell, which was the
progenitor of the carpogonial branch and lies beneath the carpo-
gonium (because of the growth and bending of this structure), now
gives rise to two cells (diagram 3, ar, a'r), one somewhat below and
the other at the side. The cell below divides once (diagram 3, a’I, a’2).
The cell at the side develops a branching group which lies close beside
the carpogonial branch, as shown in
diagram 3 (a 1,4 2,a2',a 3,a3). One
of these auxiliary cells (a 3) is formed
between the fertilized carpogonium
and the pericentral cell. Thus the
final result is two series of auxiliary
cells, one consisting of five, the other
of two cells; and in the former series
it should be remembered that one of
them has an important function, as
will appear later, becoming the path of
communication between the fertilized
carpogonium and the pericentral cell.

Puriires (60) in his studies on the
Rhodomelaceae recognized many fea-
tures in the structure of the procarp of
Polysiphonia which I have just de-
scribed. His account of a four-celled
carpogonial branch is correct, together
with the general account of the for-
Pera oo hetadd mation of the central cell, as will be
cells: pe, separ cell; yr described presently. However, I was
a2’, a3, a3’, a’1, a’2, auxiliary cells; not able to find the arrangement of
, 2, 3, cells of carpogonial branch; the auxiliary cells as he has described
Oh Of OEE them, and his investigation lacks the
cytological details through which the nuclei that enter the carpospore
must be traced.

uoydis jx +

FERTILIZATION AND DEVELOPMENT OF THE CYSTOCARP.

The jusion of the gamete nuclei—The male and female gamete
nuclei which met in the carpogonium have generally fused by the time

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 417

the auxiliary cells are formed. The membrane of the female nucleus
appears to dissolve at its point of contact with the sperm nucleus,
which lies closely pressed against it (fig. 14a), and later the chromatin
content of the male nucleus enters the female (fig. 115a). The
subsequent changes in the female nucleus result in the gradual trans-
formation of its linin network into clearly defined chromatin granules
and finally into chromosomes. At the same time the crowded group
of male chromosomes (fig. 115a) becomes looser, the chromosomes
separating from one another, some remaining near the periphery of
the fusion nucleus, and some passing into the interior. Finally the
chromosomes derived from male and female nuclei become mingled
together and the fusion nucleus assumes the appearance of prophase
(fig. 116).

The first mitosis of the fusion nucleus (sporophytic).—The fusion
nucleus which results from the union of the male and female gamete
nuclei now passes into the prophase of mitosis. The number of chro-
Mosomes is 40, which is of course double the number in the
sexual plants or gametophytes, so that the fusion nucleus is sporo-
phytic in character. These chromosomes differ from one another
in size, and some of the smaller certainly come from the male nucleus.
It would be interesting to trace carefully the history and behavior of
these chromosomes, but I am not prepared at present to discuss this
Matter in detail.

The stages of prophase in Polysiphonia, as previously described,
are always characterized by the presence of centrosphere-like structures
i the poles; however, these structures do not seem to be present dur-
ing the first mitosis of the fusion nucleus. The spindle of this mitosis
'S remarkable for its size and the breadth of the poles (jig. 1174).
Another peculiarity is the fact that the nuclear membrane disappears
during prophase, so that the spindle lies freely in the cytoplasm. It is
Possible that the early dissolution of the membrane is connected
With the fusion of the gamete nuclei, which may weaken the mem-
brane of the female nucleus. As regards the count of chromosomes,
their number 40 is apparent when the equatorial plate is viewed
ftom the pole (fig. 118a). In the late metaphase the same number
may be estimated in both groups of daughter chromosomes (jig. 123),
Which means that this first division of the fusion nucleus is a typical

418 BOTANICAL GAZETTE [DECEMBER

mitosis.. At anaphase there is present a rather conspicuous centra
spindle between the two sets of daughter chromosomes (jig. 124a).

The migration of sporophytic nuclei into the pericentral cell—There
is only one mitosis within the fertilized carpogonium. The carpo-
gonium now fuses with the auxiliary cell, which lies between it and
the pericentral cell (diagram 3, a3). The wall between these cells
dissolves and a broad communication is formed connecting them.
A fusion between this auxiliary cell and the pericentral cell follows
at once, so that the carpogonium is then in free communication with
the pericentral cell by means of the auxiliary cell. Sometimes this
communication becomes established as early as the metaphase of the
mitosis of the fusion nucleus. By means of the passage which is
established by these cell unions, the two sporophytic daughter nuclei,
resulting from the division of the fusion nucleus, move down into the
pericentral cell (figs. 125, 126).

During the formation of the auxiliary cells from the pericentral
cell each nucleus in the first three cells of the carpogonial branch
divides (figs. rrg-122). The daughter nuclei then lie side by side
in pairs within the cells of the carpogonial branch. While the sporo-
phytic fusion nucleus is undergoing mitosis, the protoplasmic connec-
tions between the cells of the carpogonial branch widen, and there is:
a movement of the cytoplasm along the branch into the carpogonium,
possibly to furnish nourishment to this cell.

The communication between the carpogonium and the adjacent
auxiliary cell is transient,. simply furnishing a passage for the sporo--
phytic nuclei into the pericentral cell. After their migration, the
carpogonium becomes detached from the auxiliary cell and remains
isolated for a while, without a nucleus, but finally breaks down with
its three sister cells of the carpogonial branch.

The formation oj the central cell and the development oj the car po-
spores.—When the carpogonium becomes separated after its union
with the auxiliary cell and the passage of its two sporophytic nuclei
into the pericentral cell, all of the auxiliary cells become more closely
united with one another. This condition takes. place by the broad-
ening of the protoplasmic communications that already exist between
them. New communications are also established between neighbor-
ing auxiliary cells, so that the entire system becomes closely bound

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 4ly

together by broad protoplasmic strands. These protoplasmic com-
munications make possible the movement of the nuclei in the auxiliary
cells towards the pericentral cell. This general cell union finally
results in the formation of a large irregular cell, the central cell,
as it was called by previous investigators (PHILLIPS 60, and others),
containing a number of nuclei. Two of these nuclei, as previously
Stated, are sporophytic and derived from the mitosis of the fusion
nucleus in the fertilized carpogonium; the other nuclei, perhaps
three or four in number, are gametophytic and derived from the aux-
iliary cells. The two sporophytic nuclei lie in the upper part of the
central cell and the gametophytic nuclei below. There are not as
many gametophytic nuclei in the large. fusion cell as might be
expected, because some of them have already broken down and the
others generally show signs of disorganization.

The two nuclei of sporophytic origin give rise to a series of mitoses
(ig. 127), and the central cell now develops several lobes, into each
of which a single sporophytic nucleus generally passes (fig. 128).
The nucleus contained within each lobe divides once more (jigs.
729, 130) and a carpospore is. cut off terminally (fig. 132) from the
lobe by a cleavage furrow, the lower portion remaining as a stalk.
cell by which the carpospore is attached to the central cell (fig. 132).

The chromosomes appearing in the mitoses previous to the forma-
tion of the carpospore are clearly 40. in number. There is therefore
ho chromosome reduction at. this period in the life history of Poly-
siphonia, for the sporophytic number 4o enters the carpospore and,
48 previously described, appears with the first mitosis at its germina-
"ton. The period of chromosome reduction in Polysiphonia is at
the time of tetraspore formation, as will. be discussed presently.
This is an important matter in relation to WoLFE’s (86) account of
Nemalion, where he reports chromosome reduction as taking place
Just before the formation of the carpospores.

After the formation of the carpospores. the central cell increases
ereatly in Size, absorbing the stalk cells (fig. 133); and finally the
cell of the axial siphon becomes involved in these extensive cell unions,
Which are probably concerned with the nourishment of the carpo-
“Pores, since sixty or more,as a rule,are developed in a single cystocarp.

ile the Carpospores are being formed, the characteristic envelop

420 BOTANICAL GAZETTE [DECEMBER

of the cystocarp becomes swollen and urn-shaped. This envelop
is developed from the peripheral siphons of the procarpic branch;
but is lined with a set of delicate filaments (jig. 132, p f), called
paranematal filaments, that arise from the cell of the axial siphon.

Some of the gametophytic nuclei derived from the auxiliary cells
break down before the unions or after the formation of the central
cell. They swell greatly, the chromatin network becomes incon-
spicuous, the membrane grows thinner and finally dissolves, so that
the nuclear contents mingle with the cytoplasm. Or, before the dis-
solution of the nuclear membrane, the network fades away, but large
nucleolus-like globules appear, which after the breaking down of the
membrane become distributed in the cytoplasm (fig. 134).

TETRASPORE FORMATION.

It is probable that true tetraspores are never formed on the sexual
plants of Polysiphonia. Certain abnormalities will be discussed
in the next section of this paper. The cell lineage of the tetraspore
in the Rhodomelaceae was correctly described by FALKENBERG (27).
HEyDRICH (41, 42) gives an account in which he contends that the
tetraspores are formed after a nuclear union within the mother cell,
and that tetraspore formation may be the forerunner of a method of
sexual reproduction. His studies seem to have been made upon
unsatisfactory material and without cytological methods, to judge
from his figures. Since I have not been able to confirm his conclu-
sions or to establish any relation between them and my own, I shall
not discuss them further.

The beginning of tetraspore formation is the development of a
pericentral cell laterally from the central siphon (fig. 140, pc)- The
mitosis previous to the formation of the pericentral cell (figs. 136-1 39)
shows that its nucleus contains 40 chromosomes. The pericentral
cell then cuts off a cell above (fig. 140, mc), which becomes the tetra-
spore mother cell, attached by a stalk (fig. 140, sc) to the central
siphon.

The formation of the tetraspore mother cell was traced in detail
through the prophase, metaphase, and anaphase of the nuclear
division in the pericentral cell (figs. 141-146), and the number of
chromosomes which enter the tetraspore mother cell is clearly 49:

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 421

Centrosphere-like structures also appear unmistakably at the meta-
phase of this mitosis (fig. 142), as well as in the previous mitosis
(fig. 137). :

The tetraspore mother cell (fig. 147) increases rapidly in size,
soon becoming very much larger than the stalk cell. With the
growth of the cell the nucleus also increases in size, and in the resting
condition shows a conspicuous linin network. This network con-
sists at first of lightly staining anastomosing threads, having knots
here and there which stain a little darker (figs. 147, 147a). The
cytoplasm presents a fine granular structure, with small alveoli.
The nuclear network undergoes gradual change in such a manner
that the lightly staining threads become somewhat thicker, and the
knots grow into large irregular masses (figs. 148, 148a). Some por-
tions of the threads connecting the knots become thinner and more
slender, at last fading away; while other portions of them become
thicker, and then the knots gradually diminish in bulk; so that, by
and by, the anastomosing chromatin network becomes transformed
into long continuous threads of irregular thickness, finally broadening
into ribbons (figs. 49, 149a).

hese chromatin threads or ribbons derived from the network
Now spread and become distributed throughout the nuclear cavity in
4 continuous and tangled fashion, presenting no free ends. It is diffi-
cult to decide whether there is a single continuous thread or a double
structure, but probably the latter condition is present, for the threads
Senerally run side by side in pairs (figs. 150, 150a). Most of the
chromatin threads become more tangled, twisted, and massed at one
- Side of the nuclear cavity, only a few traversing the cavity to the
Opposite side of the nuclear membrane. Synapsis is now generally
believed not to be an artifact, and a careful study of this stage in
Polysiphonia convinces me that the uniform chromatin threads which
Tun parallel in pairs actually fuse into a single thread in certain por
tions, although at the same time they may be separated in other parts.
All of this probably means that the two continuous threads resulting
from the transformation of the chromatin network are of distinct
origin, paternal and maternal, and that they come in contact where
they run closely parallel, and finally fuse together in the tangled and
Contracted condition of synapsis, according to the recent interpretation

422 BOTANICAL GAZETTE [DECEMBER

of ALLEN (I, 2, 3, 4), GREGOIRE (35), BERGHs (7, 8, 9, 10), ROSEN-
BERG (64, 65, 66), and others.

The period of synapsis lasts for some time, after which the spirem
becomes looser and distributed throughout the nuclear cavity. This
thread, at first uniform in thickness, begins to split longitudinally
(jigs. 152, 152a), the two parts lying close together side by side for
long distances, but sometimes diverging at wide angles and then
coming together again. The transverse segmentation of this double-
spirem to form the chromosomes now takes place, although not
simultaneously throughout the entire nucleus. The shape of these
chromosome segments is very irregular when first formed. They
may be bent or twisted like two Vs (fig. 153a, V), or two Ls (jig. 1534;
L) placed one above the other, or crossing in the form of an X (7g.
1534, X). The segments gradually shorten (jig. 154) until 20 short
rod-shaped chromosomes, bivalent in nature, are formed (jig. 155):
These are of course really the 40 sporophytic chromosomes now
grouped in pairs. The nucleolus present in the resting nucleus of
the tetraspore mother cell has not changed visibly up to this prophase
stage, taking various positions, and during synapsis being surrounded
by the tangled mass of threads. Thus the 40 chromosomes which
entered the tetraspore mother cell now appear after synapsis, which
is generally believed to be the period of chromosome reduction, as
20 pairs. These pairs become arranged in an equatorial plate and
the chromosomes of the pairs split longitudinally, so that a large
number of chromosomes results (fig. 156), probably 80 in all,
but so crowded that it is not possible to count them with absolute
certainty.

While these changes are taking place inside of the nucleus the
kinoplasm accumulates in two opposite poles outside of the nuclear
membrane. Each pole of the spindle which is formed (fig. 156) 18
occupied by a deeply staining centrosome-like body, as in the case of
the prophase of the other mitoses previously described. The form
of this spindle in the tetraspore mother cell is quite different from
other mitoses. Its longest axis runs from pole to pole instead of
across the equatorial plate, as in the other nuclear figures. Besides,
the two poles are less than 180° apart, which gives an asymmetric
or somewhat bent form to the spindle when viewed from a certain

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 423

direction, and also there are no clearly defined centrosphere-like
structures.

The spindle of the first mitosis is of very short duration. As
soon as the chromosomes at the equatorial plate separate into two
groups, the two spindles of the second mitosis suddenly appear and
the first spindle can no longer be recognized (fig. 157). It is possible
that the two poles of the first spindle may move along the mem-
brane and become poles of the second spindle, but I have no evidence
to support this suggestion. Whatever the origin of the poles of the
second mitosis, they are placed in an entirely different position from
the poles of the first. The second mitosis in the tetraspore mother cell,
therefore, follows so shortly after the first that there is no period
between for the organization of two resting nuclei.

The rapidity with which the second mitosis follows the first may
prevent the organization of centrosphere-like structures at the poles.
The axis of the two spindles of the second mitosis lie perpendicular
to each other (figs. 157, 158), and the two nuclear divisions take
place simultaneously. At anaphase four groups of chromosomes,
20 in number, pass to the poles, still included in the membrane of
original tetraspore mother cell, which persists from the beginning
(fig. 159). These four groups, of 20 chromosomes each, contain
all together the 80 granddaughter chromosomes shown in jig. 156.
When the granddaughter chromosomes reach the four poles of the two
spindles of the second mitosis, four masses of kinoplasm are present.
The granddaughter chromosomes after reaching the poles soon begin
to lose their individual outline, and become connected with one another
to form a network (jig. 160). The original nuclear cavity contains
at this stage a very large nucleolus-like body which appears during
the anaphase of the second mitosis (fig. 159). The history of this
body is not clear, but it seems to be a new structure, developing dur-
ing the second mitosis, The four poles now begin to enlarge, while
the Tegion of the nuclear membrane between them becomes flattened
(fig. 160); consequently the outline of the original nuclear membrane
is somewhat tetrahedral at this stage. The transformation of the
four Stoups of chromosomes into four chromatin nets proceeds until
4 chromatin reticulum occupies each of the four lobes of the original
Nuclear cavity,

424 BOTANICAL GAZETTE [DECEMBER

The cytoplasm of the tetraspore mother cell has large alveoli, which
pass into a finer structure at the periphery of the cell and at the nuclear
membrane. This fine alveolar cytoplasm around the nucleus joins
the kinoplasm, which lies directly against the nuclear membrane, at
the four regions formerly occupied by the poles of the spindles of
the second mitosis (fig. 160). These kinoplasmic masses extend
along the membrane between the four lobes. Finally the membrane
breaks down between the lobes and the kinoplasm enters the nuclear
cavity in the form of fibrils (fig. 161), which grow slowly towards the
center, where they finally meet around the nucleolus-like body which
now shows signs of fragmentation. The four groups of daughter
chromosomes, passing into a chromatin network, thus become sur-
rounded by kinoplasm (fig. 162) and separated from one another as
four daughter nuclei (figs. 163, 163a). During this process the
nuceolus-like body, formerly occupying the center of the nuclear
cavity, fragments into four or more portions, which become distrib-
uted to the four daughter nuclei.

The daughter nuclei and the tetraspore mother cell continue their
growth after nuclear division, these four nuclei remaining closely
associated with one another for a long while (jig. 165). Cleavage
furrows have begun to form at the periphery of the cell a little before
or after the end of nuclear division. The arrangement of these
furrows may be compared to the six edges of four spherical tetra-
hedrons whose apices are pointed towards the center of the tetraspore
mother cell. The cleavage furrows slowly grow inward (jigs. I 65;
165a), and finally meet at the center of the mother cell between the
four daughter nuclei, thus dividing the protoplast into tetraspores.
The mechanism of the cell division by cleavage furrows is similar
to that of the vegetative cells, 7. e., the furrow is assisted in its growth
inward by the fusion of the small vacuoles.

Throughout the whole process of tetraspore formation the mother
cell remains connected with the stalk cell by a strand of protoplasm,
and probably obtains nourishment through this strand, since the
developing tetraspores increase greatly in size.

ABNORMALITIES.

Normally the male and female organs and tetraspores are found
on three different individuals, but it often happens that antheridia and

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 425

procarps are produced by the same plant. Sperms are occasionally
developed in clusters at the nodal regions of older portions of fila-
ments, more often on male plants, but sometimes they are formed
hear the base of cystocarps. The sexual cells in these cases develop
normally, the successive mitoses showing 20 chromosomes.

Frequently certain of the stalk cells in an antheridium increase
greatly in size (fig. 166) and divide again and again (fig. 167). The
cytoplasmic structure and behavior of the cells resemble somewhat
the auxiliary cells of the procarp, and it seems possible that there is
present in such cases an organ of somewhat mixed character.

The most noteworthy abnormalities, however, are those where
cystocarpic or antheridial plants produce cells whose lineage is
identical with that of the tetraspore mother cell (figs. 168—170g). The
development of these cells was traced until they reached their full
Size (figs. 1 70a-170g), yet the nuclei in almost all cases remained
undivided (fig. r7od’), although the beginnings of cleavage furrows
Were observed as shallow grooves (figs. 169-170g). These cleavage
furrows never proceeded to the interior of the cell. Very rarely the
nucleus appeared to enter a mitosis (figs. 171, I71@, 171@’) in old
cells, but the number of chromosomes, small and round, were about
20 in each daughter group, and there was no evidence of reduction
phenomena; indeed, the cell was never divided. Whether this cell
may escape from the parent plant and germinate as a monospore
has not yet been determined.

It seems probable that this peculiar behavior in Polysiphonia
may offer an explanation of similar cases reported in the red algae
where tetraspores are formed on sexual plants. They have been
hoted in Chylocladia kaliformis (Lotsy 45), Spermothamnion Turnert
and Ceramium rubrum (Davis 24), and Davis has also observed
them on Callithamnion Baileyi. Such cases should be carefully
investigated to determine whether true tetraspores are present or
whether the structures are not really of the nature of monospores, as
i Polysiphonia, and developed with a suppression of reduction
Phenomena, In this case the apparent irregularity of the presence
of asexual spores on a sexual plant would be explained; or it is of
Course possible that in some cases the tetraspores are formed normally,
but the sexual organs are developed apogamously. However, it

426 BOTANICAL GAZETTE [DECEMBER

seems more probable that the first alternative will be found to be
the explanation of these exceptional conditions in the red algae.

DISCUSSION OF CYTOLOGICAL PHENOMENA.

The nucleolus.—The morphology of the nucleolus and its behavior
and function during mitoses have been studied in some detail for two
decades by many investigators in both plant and animal cells. Vari-
ous conclusions have been reached by different authors for the various
forms examined, and the same author has not unfrequently changed
his view when he came to study different material. From the excel-
lent comparative studies of Monrcomery (48) and work done later,
it is possible to summarize the essentials of the most important views
as follows.

ZACHARIAS (88) proposed the theory that the nucleolus contains
no chromatin, after FLEMMING’s conclusion (33) that there were chemi-
cal differences between true nucleoli and the chromatin reticulum.
This view has been followed by various authors, who have concluded
that there is no relation between the formation of chromosomes and
the disappearance of nucleoli. This seems to be the condition in
Polysiphonia.

STRASBURGER (72, 74) published the view that the substance of
the nucleolus is utilized for spindle formation, which conclusion was
drawn from the fact that the nucleolus in many forms disappears
partly or completely, immediately preceding the formation of the
spindle. Later NEMEC (54) suggested that the disappearance of the
nucleolus and the formation of the spindle may be regarded as two
independent events, which take place simultaneously. STRAS-
BURGER’S view has been followed by FarRcHILD (26), HARPER (38),
Witiiams (81), and-others. The spindle formation of Polysiphonia
will be considered in the next section under the heading “spindle
formation.”

STRASBURGER (70), however, formerly held the view that the
nucleolus was reserve material serving to build up the chromosomes.
This theory has been followed by PritzNER (59), GUIGNARD (37),
FARMER (29, 30), SARGANT (67), SWINGLE (76), CARNOY an
LEBRUN (13), CHAMBERLAIN (15, 16), DUGGAR (25), - ANDREWS
(5), Morttrer (52), CavARA (14), WAGER (80), and others.

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 427

Some authors have gone still further and concluded that the
chromosomes in certain forms are formed directly from the nucleolus.
The studies of the algae and of lower unicellular organisms seem
to support this conclusion. Thus TANcL (77), MEuNTIER (46),
Mot (49), DECAGNY (24a), HENNEGUY (40), MitzKEWiTSCH (47),
and VAN WIssELIncH (83, 84) on Spirogyra, GOLENKIN (34) on
Sphaeroplea, and WoLFE (86) on Nemalion hold this view. There are
naturally some differences in details among the authors mentioned
above. For example, MOoLt states that the nucleolus of Spirogyra is
found commonly exhibiting a skein structure, and that segments are
formed by the transference of chromatin substance from the nucleolus
into a nuclear plasm as small fragments arranged like beads in a neck-
lace. MirzKkewrrscu points out that during mitosis the nucleolus
increases in size and becomes differentiated into a number of deeply
staining granular chromosomes. VAN WISSELINGH believes that in
the same genus only two out of the eight chromosomes are derived
from the nucleolus, and that in the reorganization of daughter nuclei
both halves of these two chromosomes give rise to the new nucleoli.
GOLENKIN describes the nucleolus of Sphaeroplea as breaking up into
4 number of chromosomes which become arranged in a nuclear plate.
Wo.rr on Nemalion states that the material of the nucleolus passes
outward through radiating fibrillae (linin ?) into a number of chromatin
- &ranules, which organize the chromosomes directly without the inter-
vention of a spirem stage. :

The most recent study on Spirogyra is by BERcHs(1r). He
concludes that the nuclear network is not of chromatin nature, at least
it contains in the resting state little chromatin and does not take part in
the formation of chromosomes, whereas the nucleolus, at least at pro-
Phase, contains all of the chromatin elements and does not disappear
atany moment of mitosis. The nucleolus consists of two substances;
from the first, 12 chromosomes become differentiated and arranged
in a ring at the equatorial zone; the second substance remains in the
orm of the original nucleolus. The second substance at anaphase
‘plits into two groups of small rods (“‘batonnets”), forming segments
Which pass to the poles with the chromosomes. These segments are
6 in number, but are double longitudinally. The true chromosomes
become attached in pairs at the equatorial ends of these segments.

428 BOTANICAL GAZETTE [DECEMBER

The daughter nucleoli are reconstructed at the expense of the double
segments. These undergo an active vacuolization and are then con-
densed into a nucleolus in which the two substance are again mixed
together.

According to other views, there may be more than one kind of
structure called a nucleolus. CARNoy (12a) makes four groups of
these structures as follows: nucléolus nucléinieus, nucléolus noyaux,
nucléolus plasmatiques, and nucléolus mixtes, the first one being con-
sidered as portion of the chromatin network and the third concerned
with the formation of the spindle. Other authors (ROSEN 62, DAvIs
22, Wr1son 82) have recognized two kinds of nucleoli, true nucleoli
and chromatin nucleoli, the latter being considered entirely of chro-
matin.

In Polysiphonia the nucleolus lies in various positions within the
nuclear cavity, and is not connected with the chromatin network.
The chromosomes are formed from the gradual transformation or
rearrangement of the substance of the network, and the nucleolus takes
no part in their development. In Corallina also Davis (18) clearly
distinguishes the chromatin bodies from the nucleolus.

Spindle formation.—The spindle fibers in Polysiphonia are
meagerly developed and of short duration. During the prophase
of mitosis the nucleolus remains unchanged and the two poles are
marked by deeply staining bodies, but I regret that I have not been
able to trace the process of spindle formation. In the sporelings,
where the nucleus is comparatively large in size and the spindles are
more conspicuous, it was noted that short slender fibrils are attached
to the chromosomes when assembled irregularly in the middle region
of the nuclear cavity (figs. 3,17). These fibrils are the remains of the
nuclear network and are the only fibrillar structures ever seen within
the nuclear membrane at this time. The centrosome-like bodies, which
at metaphase seem to become the centers of the well-differentiated
centrosphere-like structures, have no radiation into the-cytoplasm,
though in the case of sperm mother cells a few fibrillae may be seen
running from the centrosome-like bodies at prophase (fig. 64). I
have not observed the entrance of spindle fibers from the kinoplasmic
centers outside of the nucleus, as has been reported by Davis (18)
for Corallina.

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 429

HARPER (39) states that, after the synaptic stage in the ascus of
Phyllactinia, a number of strands of chromatin are attached to a
central body, and that each strand corresponds to a single chromo-
some. He shows that the resting nucleus of Phyllactinia has definite
polarity. The formation of chromosomes from a strand of the spirem
consists in the segregation of two substances present in the spirem.
The densely staining chromatin aggregates into chromosomes, leaving
the achromatic portion as a series of threads connecting the chromo-
Somes to the central body, and these threads later form the spindle.
I have studied Polysiphonia very carefully in the hope of relating its
Process of spindle formation to that of Phyllactinia, but have not
been able to find any essential resemblance. There seems to be no
polarity to the resting nucleus of Polysiphonia as described by HARPER
for Phyllactinia.

Centrosome and centros phere-like structures—Every mitosis, no
matter where it occurs, is characterized by the constant presence
during prophase of two sharply differentiated centrosome-like bodies
in the center of the kinoplasm at opposite ends of the nucleus. When
the chromosomes are arranged in the equatorial plate the kinoplasm
has the form of a large centrosphere-like structure at the pole of the
spindle, and the centrosome-like bodies have disappeared. These
structures are destitute of the astral rays, characteristically accom-
panying typical centrosomes or centrospheres, as reported in Fucus
(STRASBURGER 73, FARMER and WILLIAMS 32), Stypocaulon (SWINGLE
76), Dictyota (Mortier 52, WittiaMs 81), and in animal cells.
They have a compact, homogeneous structure in Polysiphonia, which
makes them readily distinguishable from the surrounding protoplasm.
The daughter chromosomes, after their separation at the equatorial
Plate, become gathered close to each centrosphere-like structure
at anaphase of mitosis, and in contact with it. The latter then passes
ito a vague kinoplasmic mass which surrounds the group of daughter
chromosomes,

The observations summarized above, namely the appearance
of a centrosome-like body at prophase, its progressive development
and differentiation as a large centrosphere-like structure during
metaphase, which is the climax of the kinoplasmic activity of mitosis,
and its gradual decline after anaphase, lead me to conclude that these

430 BOTANICAL GAZETTE [DECEMBER.

structures in Polysiphonia are not permanent organs of the cell, but
are formed de novo with each mitosis, to carry on the mechanism of
nuclear division.

HARPER (39) has published an important discussion on a “central
body” discovered by him in Phyllactinia. In this form the central
body lies within the membrane of the resting nucleus, and is connected
with chromatic strands so as to give polarity to the nucleus. The
poles of the spindles are formed by division of the central body.
HARPER believes in the permanence of this structure, from mitosis
to mitosis, and in the maintenance of its connection with the chromatin.
The permanent nature of the central body in Phyllactinia and the
transient appearance of centrosphere-like structures in Polysiphonia
seem at present difficult of reconciliation.

In Nemalion WoLFE (86) reports that centrosomes are present
without astral rays at metaphase, but their continuity was not estab-
lished. The centrosphere described by Davis (18) in the tetraspore
mother cell of Corallina is formed de novo in each mitosis. Their
transient nature agrees with the somewhat. similar structures of
Polysiphonia.

The reduction oj chromosomes——STRASBURGER’S paper (7 I)
entitled ‘“‘The periodic reduction of the number of chromosomes in
the life history of the living organisms” was the first presentation of
the significance of sporogenesis and reduction phenomena in relation
to alternation of generations in plants. His conclusions were based
upon the discoveries that nuclei in the sporophyte generations of
higher plants have double the number of chromosomes found in the
nuclei of the gametophyte generations, and that the reduction of this
double number takes place at the period of sporogenesis. This
theory has been well established so far as groups of plants above the
thallophytes are concerned, and the period of chromosome reduction
has been found to be always associated with sporogenesis, and never
with gametogenesis as in the case of animals. However, among the
thallophytes our actual knowledge of facts concerning the reduction
period is meager.

Suggestions of the presence of reduction phenomena at gameto-
genesis have been made among. the fungi. in the Peronosporales
(ROSENBERG 63) and Saprolegniales (TRow 79). ROSENBERG

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 431

describes what he has called a synaptic stage in the nucleus preceding
the two mitoses concerned with oogensis in Plasmopara, and Trow
holds that chromosome reduction takes place in the two mitoses in
the oogonium of Achyla. These interpretations have been discussed
and criticized by Davis (21, 23), and the suggestions of ROSENBERG
and TRow do not seem to me convincing.

Among algae, one of the best known accounts of gametogenesis is
that of Fucus (STRASBURGER 73, FARMER and WILLIAMS 32), where,
although spermatogenesis has not been investigated, the history of
Cogenesis indicates a period of chromosome reduction. Conse-
quently the fusion nucleus in the fertilized egg has the same number
of chromosomes as the nucleus in the vegetative plants of Fucus,
which led STRASBURGER (73, '75) to conclude that the Fucus plant
is a sporophyte generation and that the gametophyte is so greatly
teduced that it is only represented by single cells —male and female
§ametes —before fertilization.

Other examples among the thallophytes in which the life history
has been worked out in some detail are Dictyota and Nemalion.
In Dictyota (Wittrams 81) the fertilized egg nucleus gives rise to
an asexual plant with double the number of chromosomes, and conse-
quently a sporophytic generation. This asexual plant develops
spores in groups of four accompanied by chromosome reduction, and
these spores develop the gametophyte generation. This type of life
history is clearly analogous to that of Polysiphonia. In Nemalion
(WoLFE 86) the fusion nucleus of the fertilized carpogonium has a
double number of chromosomes which appear in all of the cells of
the cystocarp (sporophytic) up to the formation of carpospores, where
the reduced number of the gametophyte is reported to appear.
Wotrr’s account, however, does not give the details of this chromo-
some reduction with the characteristic stage of synapsis followed by
{Wo successive mitoses.

Chromosome reduction in Polysiphonia is clearly similar to the
Phenomena of sporogenesis in higher plants, and takes place at the
time of tetraspore formation. The carpospores, containing the —
phytic number of chromosomes, continue the sporophyte generation by
developing the tetrasporic plant. The appearance of synapsis Just
Previous to the formation of the tetraspores, followed by two succes-

432 BOTANICAL GAZETTE [DECEMBER

sive mitoses with their peculiar distribution of the chromosomes, is
similar in all essentials to the reduction division in the higher plants
and in Dictyota.

The mitoses in the tetraspore mother cell have certain peculiarities
that deserve special consideration. The first mitosis is followed so
rapidly by the second that there are no resting nuclei organized between
the two divisions. In this respect the history of sporogenesis resembles
that of Pallavicinia reported by Moore (50, 51), but there is this
difference, that in Polysiphonia the granddaughter chromosomes
present in the second mitosis are formed before the first and within the
original membrane, and the organization of the four granddaughter
nuclei takes place simultaneously. However, the distribution of the
granddaughter chromosomes is clearly effected through two mitoses
and two sets of spindles, so there is never present a quadripolar
spindle such as was described by FARMER (28, 29, 30, 31) for Palla-
vicinia and some other forms of Hepaticae, and has been called
in question by Davis (19) and Moore (50, 51).

ALTERNATION OF GENERATIONS.

Alternation of generations—Judging from the studies of Poly-
siphonia presented above, the male and female plants with their 20
chromosomes are gametophytes. The union of the male and female
nuclei results in the fertilized carpogonium with the double number
of chromosomes (40), marking the beginning of a new phase, the
sporophyte generation. This fusion nucleus gives rise to a series
of mitoses in the central cell of the cystocarp, all characterized by
the double number of chromosomes, and consequently sporophytic in
character, and carpospores are finally formed. The carpospore 0m
germination presents the same number of chromosomes (49), and the
successive mitoses following contain this number, so that the sporeling
developed from the carpospore is still a part of the sporophytic phase.
It may never be possible to grow such sporelings to maturity under
experimental conditions, but it is evident that the plant developed
from the carpospore must have nuclei with 40 chromosomes, until
there is some marked change in the life history. The only vegetative
form of Polysiphonia with 40 chromosomes is the tetrasporic plant,
from which it must be inferred that the tetrasporic plant arises from

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 433

the carpospore and constitutes a part of the sporophyte generation
that begins with the fertilized carpogonium .

This long sporophytic phase terminates with the formation of
tetraspores, when a reduction of chromosomes takes place, 20 chromo-
somes entering each tetraspore. These tetraspores with the reduced
number of chromosomes evidently have returned, with respect to
nuclear conditions, to the potentialities of the original gametophyte
or sexual generation. Again, it may never be possible to grow spore-
lings from the tetraspore to maturity under experimental conditions,
but it is evident that plants derived from the tetraspores must have
nuclei with 20 chromosomes. The sexual plants of Polysiphonia are
the only forms in which 20 chromosomes are found, therefore it may
safely be concluded that the sexual plants arise from tetraspores. The
tetraspore then constitutes an indispensable part of the life history
of Polysiphonia, and cannot be regarded simply as an accessory type
of reproductive structure, such as is illustrated by many forms of
asexual spores in the thallophytes or by the gemmae of bryophytes.

To summarize the life history of Polysiphonia, the gametophyte
§eneration begins with the tetraspores and ends with the sexual cells
or gametes, whose fusion initiates the sporophyte generation; this
covers a long period, including the formation of carpospores, germina-
tion of Carpospores, development of the tetrasporic plants, and at
last ends with the formation of tetraspores. In other words, the
sexual plants and the tetrasporic plants present the two distifct phases
of an antithetic alternation of generations, with the cystocarp a part
of the sporophytic phase, The life history of Polysiphonia may be
tabulated as follows:

Gamet hut; * Pp g
E g

|

(Germination) Doubling of cheats (Germination) Reduction of chromosomes

T ~ ey a T
etraspore—s nucleus (20 EE Ty, ic plant-Tetras|
(20). : wt eae —_———— oe pita (20,
nucleus (20)
Taking up the theories concerning the life history of the red algae,
OLTMaNNs (55) concluded eight years ago, from an investigation of
{our genera (Dudresnaya, Glocosiphonia, Callithamnion, and
Dasy a), that the structure derived from the fertilized carpogonium

434 BOTANICAL GAZETTE [DECEMBER

is comparable to the sporophyte generation of the higher plants.
At that time he expressed his opinion definitely that the tetraspore is
a special form of reproductive cell, comparable to brood cells or gem-
mae, and with no fixed place in the life history. However, during the-
last year (56, p. 273) he has admitted the possibilities of reduction
phenomena during tetraspore formation.

Davis (24, pp. 467, 471) in the same year definitely suggested
the probability that reduction phenomena would be found in the
tetraspore mother cell.

WILLIAMs (81) discovered chromosome reduction during tetra-
spore formation in Dictyota, which led him to conclude that the
tetrasporic plant in Dictyotaceae is a sporophyte generation derived
from the fertilized egg.

Wo tre (86) showed for Nemalion that the cells of the cystocarp
have double the number of chromosomes found in the sexual plant,
thus presenting the first cytological evidence that the cystocarp of
the red algae is sporophytic in character. He places the period of
chromosome reduction at the time of carpospore formation, basing
his conclusion on a count of chromosomes in the mitosis just previous
to the formation of the carpospores. However, he did not report
the phenomena characteristic of chromosome reduction, namely
the period of synapsis followed by the two mitoses which distribute
the chromosomes so as to give a numerical reduction.

Recently STRASBURGER (75) has published his views concerning
the alternation of generations in the brown algae, remarking that
the tetraspores of the red algae seem to be different from those of the
Dictyotaceae, and that the place of the chromosome reduction in the
red algae should be sought elsewhere than at tetraspore formation,
because some of the red algae develop no tetraspores, but instead
form monospores. It is true that in some groups of red algae tetra-
spores are never formed, and in certain of these monospores are
present. In these cases chromosomie reduction may take place with
the formation of the carpospores, or perhaps with their germination,
and the monospore when present may have no vital relation to the
main cycle of the life history. The group of the red algae is very
large and contains a great variety of forms, with a wide range in the
complexity of the cystocarp and the vegetative forms, so that It 1

:

Cae eee eee ee ee eee et
Eee as (gu eae Se a ee er
a eae :

1906) YAMANOUCHI—POLYSIPHONIA VIOLACEA 435

reasonable to expect important differences in the position of the period
of chromosome reduction.
Origin of the tetraspore-—The simplest genera of the red algae,

such as Lemanea, Batrachospermum, Chantransia, and Nemalion,

have no tetraspores, but some of them have monospores, as in Chan-
transia and Batrachospermum (including the Chantransia form).
In these types the period of chromosome reduction may be associated
with the carpospore, either just before its development or at the time
of its germination. The monospores, then, in such genera are not
vitally concerned with the life history, and indeed are present upon
the gametophyte. The tetrasporic plant may have arisen by a sup-
pression of the reduction phenomena in connection with the carpo-
Spore, so that it germinates with the sporophytic number of chromo-
Somes, producing a plant with this number, which consequently
becomes at once a part of the sporophytic phase. The period of
chromosome reduction would be thus postponed from the carpospore
to a later period in connection with the newly formed plant. Such
plants by developing tetraspores would end the sporophyte generation.
It is quite possible that the first tetraspore mother cells corresponded
to monospores on the sexual plants except that they had the double
number of chromosomes, since such reproductive cells would very
naturally become the seat of the delayed reduction phenomena. The
resemblance in general morphology of the tetrasporic plants in the
ted algae to the sexual plants would be expected, because they live
under similar environmental conditions, and we have another illus-
tration of Such similarity of gametophytes and sporophytes in the
Dictyotaceae.

Abnormalities of the nature of monospores.—It should be remem-
bered that sexual plants (cystocarpic) of Polysiphonia occasionally
develop an abnormality in the form of a cell resembling a monospore
but having the same cell lineage as the tetraspore mother cell. This
abnormality may indeed be a reversion to an ancestral type of mono-
spore, that in the process of evolution has given place to the tetraspore
mother cell, which is only found in the sporophytic generation. It
may be, however, simply an exceptional condition without any
Phylogenetic significance.

436 BOTANICAL GAZETTE [DECEMBER

SUMMARY.

The nuclear conditions in the life history of Polysiphonia violacea
may be summarized as follows:

1. The carpospore on germination shows 40 chromosomes, and
40 chromosomes appear in the vegetative mitoses of the tetrasporic
plant; so it may be inferred that the tetrasporic plants come from
carpospores.

2. The tetraspore on germination shows 20 chromosomes, and
20 chromosomes appear in the vegetative mitoses of the sexual plant;
so it may be inferred that the sexual plants come from tetraspores.

3. The nuclei of the gametes (sperm and carpogonium) contain
each 20 chromosomes. The fusion nucleus (sporophytic) in the
fertilized carpogonium as a result has 40 chromosomes and gives
rise to a series of nuclei in the central cell. Some of these enter the
carpospores, which are consequently a part of the sporophytic phase
to be continued in the tetrasporic plant. The gametophyte nuclei
in the central cell of the cystocarp with 20 chromosomes break down.

4. Tetraspore formation terminates the sporophytic phase with
typical reduction phenomena, so that the tetraspores are prepared
to develop the gametophyte generation.

5. There is thus an alternation of a sexual plant (gametophyte)
with a tetrasporic plant (sporophyte) in the life history of Polysiphonia,
the'cystocarp being included as an early part of the sporophytic phase.

THE UNIVERSITY OF CHICAGO.

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)
;
q
7
4

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 437

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24a, Decacny, Cu., Recherches sur la division du noyau cellulaire chez les
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25. Duccar, B. M., On the development of the pollen grain and embryo sac in
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26. Farrcurip , D. G., Ueber Kerntheilung und Befruchtung bei Basidiobolus
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27. F ALKENBERG, P., Die Rhodomelaceen des Golfes von Neapel und der

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438 BOTANICAL GAZETTE [DECEMBER

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, Spore formation and karyokinesis in Hepaticae. Annals of Botany

20.
9: 363. 1895.

30 , On spore aoe and nuclear division in the Hepaticae. Annals
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31 ee ie spiadis in the spore mother cell of Pellia epiphylla.

‘Annals of Botany 15:431. Igor.
32. Farmer, J. BRETLAND, and Wix1iAms, J. Lioyp, Contribution to our
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33. FLemMine, W., Zellsubstanz, Kem und Zellteilung. Leipzig. 1882.
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36. Grécorrr, Victor, and Wycarrts, A., La réconstitution du noyau et la
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1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 439

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EXPLANATION OF PLATES XIX-XXVIII.

The figures were drawn with the aid of an Abbé camera lucida, under Zeiss
apochromatic obj. 1.5™" N. A. 1.30, combined with compensating ocular 18;
except figs. 13, 14, 133, 134 drawn with compensating ocular 12; jigs. 193,
109, 114-118, 124, 126, 132, 135, 163-171 drawn with ocular 4; and jigs. O50
744, 1474,-153a, 1710’ drawn with compensating ocular 18 under higher ma
cation obtained when the tube was extended to the furthest point. The plates
are reduced one-half the original size, except plates XXI, XXII and XXVIII,
which are reduced two-fifths.

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 441

PLATE XIX.
The first mitosis in the germinating tetraspore.

Fic. 1. Nucleus in resting stage, showing delicate linin network and nucleolus.

Fics. 2a-2c. Three sections of the same nucleus, showing segregation of
chromatin material into about 20 groups, probably prochromosomes, before the
formation of chromosomes.

Fics. 3a, 3b. Two sections of the same nucleus, early prophase; 20 chromo-
Somes may be counted.

1G. 4. The late prophase; centrosome-like bodies lying at Mom ee

Fic. 5. Metaphase showing equatorial plate; nuclear still present;
neuclear cavity considerably smaller than in the preceding stage.

Fic. 6. Membrane dissolving; centrosphere-like structures present at the
Poles of the spindle.

1c. 7. The polar view of an equatorial plate showing 20 chromosomes and

the remains of nucleolar material.

Fic. 8. Anaphase, showing groups of daughter chromosomes assembled Bt
the iis of the spindle

ae 9. La oa the original nuclear membrane entirely dissolved;
— structures passing into vaguely outlined kinoplasmic masses,

Fic. 10. Polar view of late anaphase; space within the group of chromosomes
probably ; thai the first appearance of nuclear sap within a vacuo a

Fie. rr. Telophase; the membrane of the daughter nucleus is roe errs ;

1G. 12. Resting condition of daughter nucleus, showing linin network an

two nucleoli, ; :

Fic. 13. Cleavage furrow appearing at the periphery of the cell in the middle
region,

Fic. 14. The cleavage furrow has penetrated almost to the sone the =
leaving only a Narrow passage admitting of protoplasmic continuity between
daughter cells.

PLATE XX.
The first mitosis in the germinating car pospore.

rk.
Fic. 15. Nucleus in the resting condition, showing linin netwo. ;
ie 16a-16c. Three sections of the same nucleus, showing 40 prochromo

ition 17a, 17b. Two sections of the same nucleus, eatly prophase; 40 chromo-
eg a. im Two sections of the same nucleus; centrosome-like bodies
oc
ie showing equatorial plate; centrosphere-like structures
at t
F ea Pile ee of an equatorial plate showing group ‘of 40 chromosomes
and the remains of nucleolar material.

442 BOTANICAL GAZETTE ~ [DECEMBER

Fic. 21. Anaphase; groups of daughter chromosomes become assembled at
the poles of the spindle.

Fic. 22. Later anaphase; original nuclear membrane entirely dissolved;
centrosphere-like structures passing into vaguely outlined protoplasmic masses.

IGS. 23a, 23b. Two sections of the same daughter nucleus in late anaphase

viewed from the pole, showing early stage in — of the vacuoles containing
nuclear sap.

Fics. 24-24c. Three sections of the same daughter nucleus ae after
telophase; nuclear membrane clearly formed and two nucleoli prese

Fic. 25. Resting condition of daughter nucleus, showing linin ate and
nucleolus

PLATE XXI1,

Mitosis in the vegetative cells of the male plant.
Fic. 26. Apical cell of main filament; resting nucleus of an apical cell, show-
ing linin network.
1G. 27. The same; network becoming coarser.
Figs. 28-35. Apical cells of developing hairs.
Fic. 28. Chromatin granules aggregated into 20 prochromosomes.
Fic. 29. Prophase; 20 chromosomes clearly present; a centrosome-like body
at each pole.
Fic. 30. Metaphase showing equatorial plate; centrosphere-like structures
at the poles of spindle.
Fic. 31. The polar view of equatorial plate showing 20 chromosomes.
1G. 32. Late metaphase; two groups of daughter chromosomes just separ-
ating.
Fic. 33. Anaphase; two groups of daughter chromosomes separated by a
large vacuole which enters between them
Fic. 34. Telophase; nuclear membrane around the daughter nuclei.
Fic. 35. Later stage than the previous figure; cleavage furrow proceeding
inward so as to divide the apical cell.

Mitosis in the vegetative cells of female plants.
Figs, 36-42. Apical cells of developing hairs.

Fic. 36. Prophase of nucleus; centrosome-like body present at the pole.

Fic. 37. Metaphase, showing equatorial plate; centrosphere-like structure
conspicuous.

Fic. 38. The polar view of metaphase.

Fic. 39. Late metaphase

Fic. 40. Anaphase.

Fic. 41. Anaphase; the vacuole beginning to intrude between the groups of
daughter chromosomes.

Fic. 42. Telophase; cleavage furrow appearing between the two daughter
nuclei.

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 443

43- Mitotic figure in the old region of thallus, showing large centrosphere-
lke st. pace.
1G. 44. Polar view of the same stage as the above, showing 20 chromosomes.
Mitosis in the vegetative cells of the tetrasporic plant.
Figs. 45-51. All apical cells of main filament.
Fic. 45. Resting nucleus, showing linin network.
Fic. 46. Chromatin granules commence to aggregate to form prochromo-
somes,
Fic. 47. Early prophase showing 40 chromosomes.
Fic. 48. Metaphase showing equatorial plate; centrosphere-like structures

Ftc. 49. Late metaphase; groups of daughter Solan separated.
Fic. 50. Polar view of metaphase showing 40 chromosom
Fic. 51. Anaphase; vacuole intruding between two Sia of daughter
chromosomes.
PLATE XXIi,

Spermatogenesis.
Figs. 52-61. Formation of the sperm mother cell.

Fic 52. Terminal portion of a very young antheridium, consisting of an axial
siphon of three cells; the nucleus of the lower cell is in a resting condition; the
middle one in early prophase; and the upper one in anaphase.

Fic. 53. Mitotic figure in a cell of the axial siphon to form a stalk cell laterally.

Fic. 54. A cell of the axial siphon with the stalk cell formed laterally.

Fic. 55. Prophase in the stalk cell showing 20 chromosomes.

Fic. 56. Metaphase showing equatorial plate; centrosphere-like structures

Fic. 57. Polar view of the same stage as in the preceding figure, showing 20
chromosomes.

Fic. 58. Late metaphase stage; nuclear membrane still present.

FR 9. Anaphase; vacuole intruding between two groups of daughter
en cen

Fig. 60. Still later stage of anaphase.

IG, sh ee cleavage furrow separating the sperm mother cell from
the stalk
Figs. 62-74. Formation of the first sperm.

Fic. 62. Resting nucleus of sperm mother cell, showing linin network.

Fic. 63. Fine reticulum transformed into 20 prochromosomes.

Fic. 63a. Portion of fig. 63 under higher magnification.

Fic. 64. Prophase; a few spindle fibers attached to the chromosomes; centro-
Some-like bodies at the poles.

Fic. 64a. Portion of fig. 64 under higher magnification

Fic. 65. Metaphase; the centrosphere-like structures evident.

444 BOTANICAL GAZETTE [DECEMBER

Fic. 65a. The nucleus of jig. 65 under higher magnification.

Fic. 66. The polar view of the stage shown in the previous figure; 20 chromo-
somes clearly present.

F 7. Late metaphase.

Fic. 68. Anaphase; vacuole intruding between the two groups of daughter
chromosomes.

Fic. 69. Later stage of anaphase.

Fic. 70. Lower nucleus passing into resting condition.

Fic. 71. Cleavage furrow separates the sperm above from the sperm mother
cell which is destined to produce later a second sperm.

Fic. 72. Sperm almost formed; the sperm mother cell beginning to elongate,
preliminary to the development of a second sperm

Fic. 73. Side view of mature sperm

Fic. 74- Sperm viewed from above; } maintaining their individual
forms.

Fic. 74a. Portion of fig. 74 under higher magnification.

Figs. 75-81. Formation oj the second sperm.

Fic. 75. Prophase of mitosis to form second sperm; the first sperm still present
at the side, so that the sperm mother cell assumes an asymmetrical outline.

Fic. 76. Metaphase showing equatorial plate; centrosphere-like structures
present.

Fic. 77. Polar view of same stage as in previous figure.

1G. 78. Late metaphase.

Fic. 79. Anaphase.

Fic. 80. Later anaphase; vacuole between the two groups of daughter
chromosomes.

Fic, 81. Cleavage furrow separating the second sperm from the sperm mother-
cell.

PLATE XXIiI.
The formation of the procarp.

Fic. 82. Mitotic figure in the cell of the central siphon of a procarp, to form
the first peripheral cell; centrosphere-like structures present.

Fic. 83. Polar view of the same mitosis, showing 20 chromosomes.

Fic, 84. First peripheral cell is formed.

Fic. 85. Mitosis to form second peripheral cell.

Fic. 86. Polar view of the same mitosis; 20 chromosomes present.

Fic. 87. Anaphase of the same mitosis.

Fic. 88. The fifth peripheral cell, called the pericentral cell, formed on the
left of the central siphon; this cell is destined to develop the carpogonial branch.

Fic. 89. Mitosis to form first cell of the carpogonial branch from the peri-
central cell.

Fic. 90. Polar view of the same stage as the previous figures, showing 20
chromosomes.

1906] YAMANOUCHI—POLYSIPHONIA VIOLACEA 445

Fic. 91. Anaphase.

Fic. 92. Late anaphase. :

Fic. 93. Telophase; vacuole intruding between the daughter nuclei.

FIG. 94. Mitotic figure to form second cell of the carpogonial branch; #c,
pericentral cell. ;

Fic. 95. Polar view of the same stage as shown in the previous figure; 20 chro-
mosomes readily seen. :

Fic. 96. Mitotic figure forming the third cell of the carpogonial branch.

Fic. 97. Polar view of the same stage. :

Fic. 98. Mitotic figure to form the fourth cell of the carpogonial branch.

FIG. go. iew of the previous figure.

F = fe preci a eb oe weit fourth cell of carpogonial branch,
which develop the trichogyne and carpogonium; this mitosis gives rye ee
nuclei as shown in fig. 101; being cut obliquely, the chromosomes, 20 in number,
may be counted.

ie oe two nuclei within the carpogonium or the fourth cell of the
Catpogonial branch: pc, pericentral cell.

PLATE XXIV.
Development of the trichogyne.
Fic. 102. Development of the trichogyne from the carpegosiae: :
Fic. 103. A mature procarp in section, showing the situation of the carpo
Sonial branch: c, pericentral cell; as, axial siphon. ;
Fig. 104. Carpogonium with trichogyne at maturity; si ee ie =
Size between the sister nuclei, for the carpogonium with its nucleus
greatly.
Fertilization.
Fic. 105. Sperm attached at the tip of the trichogyne. :
ing i i ; note the
Fic. 106. Contacts of sperm, its nucleus passing into trichogyne; note
individual chromosomes in the sperm nucleus. ie
Fic. 107. Sperm cell emptied of contents; sperm nucleus about to pass
trichogyne nucleus. ont as
Fic. 108. Sperm nucleus having passed the trichogyne nucleus is a
enter the carpogonium. re
Fic. 109. Section of procarp showing the situation of the carpogonium
time of fertilization. : eS
Fic. 1o9a. The carpogonium of fig. 109 under higher — ei ae
nucleus about to fuse with the female nucleus, which has moved up
Carpogonium. s OTT
Fic. 110. Mitotic figure in the formation of an auxiliary a sere ara Ti
tral cell, which takes place parallel with the nuclear fone: ae or
Fic. ea at Prophase of the 1 LGN eon Bee Maa g 20 cnr
Fic. 112. Mitosis in a cortical cell of the procarp.

446 BOTANICAL GAZETTE [DECEMBER

Fic. 113. Polar view of the above mitosis, showing 20 chromosomes.

Fic. 114. Section of procarp showing situation of the carpogonium at the time
of contact between the sperm and carpogonium nuclei.

IG. 114a. The carpogonium of fig. rq under higher magnification; the sperm
nucleus beginning to fuse with the female; no membrane observable around the
sperm nucleus since the beginning of entry of it into the trichogyne; the female
nucleus in resting condition.

Fic. 115. Section of procarp showing carpogonium at a late stage in the fusion
of the sential nuclei.

Fic. r15a. The carpogonium of fig. 115 under higher magnification; the
chromosomes of the sperm nucleus beginning to separate in the female nucleus;
the network in female nucleus preparing to form chromosomes.

Fic. 116. The fusion nucleus in the carpogonium after the female chromo-
somes have been formed, showing a mingling of male and female; the total
number of chromosomes js 40.

Developinent of the cystocarp.

Fic. 117. Section of anes at the time of the first mitosis of the fusion
nucleus within the carpogonium.

Fic. 117a. The eepcenia of ig. 117 under higher magnification, showing
the first mitosis of the fusion nucleus

Fic. 118. Procarp showing the Sint mitosis of the fusion nucleus in the carpo-
gonium; cut obliquely.

Fic. 118a. The carpogonium of fig. 118 under higher magnification, —
a polar view of first mitosis of the fusion nucleus; 40 chromosomes prese

Fic. 119. Prophase of a nucleus within the first cell of the carpogonial ok

Fic. 120. Metaphase of the above mitosis.

Fic. 121. Polar view of the same mitosis showing 20 chromosomes.

Fic. 122. Anaphase of the same mitosis.

PLATE XXV.

Fics. 123a, 123b. Two sections of the fusion nucleus at metaphase of the
first mitosis.

124. Section of the procarp at anaphase of the first mitosis of the fusion
Rebe within the carpogonium.

Fic. 124a. The carpogonium of fig. 124 under higher magnificatio

Fic. 125. Migration of one of two daughter nuclei FOS resulting
from the first mitosis of the fusion nucleus, into the third auxiliary cell (compare
with a3 in diagram 3).

Fic. 126. Migration of two daughter nuclei (sporophytic) into the pericentral
cell, the third auxiliary cell having fused with it; a nucleus from one of the aux-
iliary cells below also entering the peticentral cell; the first, second, and
cells of the carpogonial branch, together with the carpogonium, about to collapse.

Fic. 127. Mitoses of two sporophytic nuclei derived from the fusion nucleus
and of a gametophytic nucleus also within the central cell; the distinction between

1906] YAMANOUCHI~—POLYSIPHONIA VIOLACEA 447

the mitotic figures is readily seen by estimating the number of chromosomes
arranged in the equatorial plate.

Fic. 128. Sporophytic nucleus in a process from the central cell, from which
after a mitosis a carpospore will be formed; the nucleus in prophase; 40 chromo-
somes may be counted.

Fic. 129. Metaphase of the mitosis which separates the carpospore from the
Stalk cell.

Fic. 130. Polar view of the same mitosis cut obliquely, showing 40 chromo-
somes.

Fic. 131. Telophase of the same mitosis; the upper nucleus will lie in the
Carpospore.

Fic. 132. Section of a cystocarp, showing central cell (cc), stalk cell (sc),
Catpospore (sp), and paranematal filaments (pf).

Fic. 133. Stalk cells beginning to fuse together side by side, and their nuclei,
with other nuclei remaining in the central cell, beginning to disorganize.

Fie. 134. Disorganizing nuclei in the central cell.

Fics. 135a-135d. Four sections of a procarp, showing the arrangement of the
auxiliary cells (compare with diagram 3); the fusion nucleus in the carpogonium
(carp) shows the mingling of male and female chromosomes.

PLATE XXVI.
The tetraspore formation.

Fic. 136, P Tophase in a cell of the central siphon previous to the formation
of pericentral cell, showing 4o chromosomes.

Fic. 137. Metaphase of this mitosis.

Fic. 138. Anaphase.

Fic. 139. Polar view of anaphase; 40 chromosomes present.

Fic. 140. Tip of a filament, showing stages in the formation of the tetraspore
mother-cell; pc, pericentral cell; sc, stalk cell; tmc, tetraspore mother cell.

1G. 141. Chromatin network in resting nucleus of pericentral cell.
IG. 142. Metaphase of the mitosis in the pericentral cell; centrosphere-like
structures present.

Fic. 143. Late metaphase of the same.

Fic. 144. Anaphase. :

Fic. 145. Telophase; vacuole intruding between the daughter nuclei.

Fic. 146, Tetraspore mother cell becoming separated from the stalk cell by
the Cleavage furrow. : es

1G. 147. Later stage of the above; tetraspore mother cell increased in size;
the nucleus with delicate linin network.
1G. 147a. Portion of linin reticulum in jig. 147 under higher i

Fic. 148. Reticulum becoming transformed into a coarser chromatin network
with here and there la knots upon the threads. :

Fic. 148a, Porticas a wtwakboe fig. 148 under higher magnification.

Fic. 149. Irregular network becoming transformed into more even threads.

ification.

448 BOTANICAL GAZETTE [DECEMBER

Fic. 149a. Portion of threads from fig. 149 under higher magnification.

Fic. 150. Threads becoming arranged parallel to one another.

Fic. 150a. Portion of threads from fig. 150 under higher magnification.

Fic. 151. Synapsis.

Fic. 151a. Portion of the parallel threads from jig. 151 fusing in parts, under
higher magnification.

Fic. 152. Nucleus emerging from synapsis.

Fic. 152a. Portion of fused parallel threads or spirem from fig. 152 under
higher magnification; the spirem beginning to split longitudinally.

1G. 153. Later stage than the above; spirem beginning to segment to form

chromosomes; the split segments arranged side by side.

Fic. 153a. Segments of spirem from fig. 153 under higher magnification,
showing xX and double t and vy forms.

PLATE XXVIII.

Fic. 154. Early prophase of mitosis in tetraspore mother cell; 20 bivalent
chromosomes are present. .

Fic. 154a. Chromosomes from fig. 154 under higher magnification, showing
bivalent character.

Fic. 155. Later prophase; bivalent chromosomes have been shortened.

Fic. 156. Metaphase; a great number of chromosomes (about 80) arranged
in the equatorial plate; this large number results from the premature division of
the halves of the bivalent chromosomes shown in fig. 155; the 80 chromosomes
are therefore granddaughter chromosomes, which will be distributed to the four
tetraspores; centrosphere-like structures poorly differentiated.

Fic. 157. Later metaphase of the first mitosis; two groups of daughter
chromosomes, 40 in each, just separating and the four poles of second spindle
already differentiated.

Fic. 158. Metaphase of 1 mitosis; four groups of sade chromo-
somes (three seen) passing to the poles.

Fic. 159. Groups of granddaughter chromosomes at the poles; nucleolus
has appeared in the center of se sun seat ease

Fic. 160. Groups of g forming chromatin network;
membrane surrounding the nuclear cavity assuming a tetrahedral shape with

kinoplasm accumulating at the lings

Fic. 161. G I formed an anastomosing
chromatin network; membrane cana nuclear cavity has broken in the
region between the four poles so as to admit the entrance of kinoplasmic fibrils
without the membrane; the fibrils grow toward the center of the nuclear cavity.

Fic. 162. Daughter nuclei becoming separated by the growth of kinoplasm
which surrounds the chromatin network.

Fic. 163. Tetraspore mother cell at the time of F separation of the daughter
nuclei.

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YAMANOUCHI—POLYSIPHONIA VIOLACEA 449

Fic. 163a. The nuclei of fig. 163 under higher magnification, showing the
Tucture with linin network and nucleoli.

Fic. 164. The four daughter nuclei are completely formed (two visible);

Sa furrow appearing at the periphery.
G. 164a. Portion of jig. 164 under higher magnification, showing details
of oe furrows.

Fic. 165. T, etraspore mother cell with cleavage furrows growing towards the
center.
Fic. 165a. Portion of fig. 165 under higher magnification, showing the vacuolar
structure and the progress of the cleavage furrows.
PLATE XXVUI.
Abnormalities.

Fic. 166. A young antheridium in which a stalk cell has increased in size and
umed the appearance of an auxiliary cell in the procarp.
Fic. 167. Showing the division of a stalk cell; de black spot within the cell
indicates transverse section of protoplasmic sthende connecting it with other
Stalk cells above or below
Fic. 168. A cell ceeed on a sexual plant whose lineage is similar to that
the tetraspore mother cell.

Fic. 168a. This cell from fig. 168 under higher magnification; the nucleus in
a resting condition.
Fic. 169. Still later stage in the formation of this cell.

‘IGS. 170a-170g. Seven sections of a similar cell; nucleus remains undivided,
although the eins of a cleavage furrow is present, which however never

Fic. 170d’. eden of fig. r7od under higher magnification, in a resting
condition,

Fic. 171. A rare’case where the nucleus of this cell undergoes a typical mitosis.
Fic. 171a, The nucleus of jig. 171 under higher magnification

Fic. 1714’. The mitotic figure of jig. 171a under still higher a
Shows that this division is typical and that the daughter chromosomes are 2
number in each;, . group.

THE MORPHOLOGY OF THE ASCOCARP AND SPORE-
FORMATION IN THE MANY-SPORED ASCI OF
THECOTHEUS PELLETIER I.

JAMES BERTRAM OVERTON.

(WITH PLATES XXIX AND XXX)

ALTHOUGH free cell formation and spore formation have been
thoroughly described by several authors, the process has not been
followed in asci containing more than eight spores. In view of the
old and widely held opinion that the ascus closes a sporophyte gen-
eration and is a spore mother cell, the study of the development of
a many-spored ascus becomes especially important. The correlative
phenomenon of the regular formation of eight nuclei in the ascus by
a triple division, whether eight spores or less are to be formed, has
been well established; but the variations from the typical method
of spore formation and the necessary nuclear and cell divisions, by
which more than eight spores are formed, are still in need of further
study, and may prove valuable in aiding to solve the character of
this peculiar organ. The presence of a true sexual process in the
higher fungi, especially among the Ascomycetes, has been established
beyond a doubt by the investigations of HARPER and others, but
much still remains to be learned concerning the morphology of the
sexual organs and ascogonia in the individual forms of this group.

The present investigation was undertaken during the past year,
in order to determine the method of spore-formation in many-spor
asci. Thecotheus Pelletieri presented itself as favorable material.
Incidentally stages in the development of the ascocarp have been found
which will also be described. The fungus agrees in general with
the descriptions and figures of Thecotheus Pelletieri (Cr.) Boud.,
except that the asci are Jess conspicuously exserted than shown in
the figures of CRouAN (’57), BoupreR (’69), PATourmLtaRD (’83);,
and Rex (’96), and the spores are also faintly colored. BoUDIER,
to whom I have also sent material, has had the kindness to examine
the fungus and has confirmed the determination, with the note,
however, that he finds the spores somewhat larger than in the type.
Botanical Gazette, vol. 42] [45°

ey ee eC gs any Ee ae ne he ee

1906] OVERTON—THECOTHEUS PELLETIERI 451

As will be seen from the description below, the form differs from the
species of Ryparobius described by BARKER (:03, :04) in having
several ascogonia instead of a single one. As it may be found that
this is a character of generic significance, I have thought best to follow
BoupteR in including this form under a separate generic name.

The investigation of the Ascomycetes has shown that there are
great variations in the morphology and development of both fruit
bodies and reproductive organs, and a sharp distinction may be
made as to whether the sexual organs, associated with ascocarp
formation, occur singly or in groups. Below I have brought together
those forms whose fruit bodies develop from a single ascogonium, as
contrasted with those whose ascocarps develop from several ascogonia.
In strong contrast to these may also be added a third group of appar-
ently apogamous forms, whose fruit bodies develop directly from a
cell of the mycelium without the appearance of sexual organs.

I. In the following forms the ascocarps develop in connection
with a single set of sexual organs: Monascus (BARKER :03, OLIVE
:05), Dipodascus (JUEL :02), Gymnoascus (BARANETZKY ’72, VAN
TIEGHEM 76, 77, Erpam ’83, Miss DALE :03), Erysiphe cichorace-
arum (Sphaerotheca castagnei) (DEBARY 63, HARPER 95), Erysiphe
galeopsidis (DEBARY ’70), Erysiphe communis (DEBARY 70, HARPER
96), Sphaerotheca humuli (BLACKMAN & FRASER :05), Phyllactinia
corylea (HARPER :05), perhaps Eurotium repens, Aspergillus glaucus,
(DeBary ’70), Penicillium glaucum (BREFELD ’74), Aspergillus glau-
cus (VAN TIEGHEM ’7'7), Chaetomium (VAN TIEGHEM’75, 76, EIDAM
83, ZUKAL’86, OLTMANNS ’87), Stictosphaeria Hojfmanni, with sev-
eral species of Diatrype, Eutypa, Quaternaria, and Xylaria (FUISTING
67), Sphaeria lemaneae, Sordaria fimiseda (WORONIN 70, GILKENET
74), and Ceratostoma brevirostre, Hy pocopra sp. (Miss NICHOLS ’96).
Among the Discomycetes the following investigated forms show a
single ascogonium: Ascobolus jurfuraceus (JANCZEWSKI 72, HARPER
96), A. pulcherrimus (WoRONIN ’66), Ryparobius sp. (BARKER :03,
:04), Peziza granulosa, Lachnea scutellata (WORONIN 66), Humaria
granulata (BLACKMAN & FRASER :06), Ascodesmis nigricans (VAN
TiecHeM ’76), and Thelebolus stercoreus (RAMLOW :06).

Il. Pyronema confluens (TULASNE 66, DEBARY 63, KIHLMAN
°83, HarpPER :00), several species of Collema (Baur ’98), Parmelia

452 BOTANICAL GAZETTE [DECEMBER

acetabulum (BAUR :01, :04), Anaptychia ciliaris, Lecanora subjusca,
Endocar pon miniatum, Gyro phora cylindrica, Cladonia pyxidata (BAUR
:04), Peritusaria communis, Pyrenula nitida (BAUR :01),and Boudiera
Clausseni (CLAUSSEN :05) represent the only forms thus far described
in which the ascocarp is developed in connection with several
ascogonia. As described below, Thecotheus also possesses a com-
pound ascogonial apparatus from which the fructification originates.

II. In certain Pyrenomycetes ascocarp formation is apparently
independent of sexual organs, being initiated by the formation of a
parenchymatous mass of tissue, which is formed by the division of a
single hyphal cell of the mycelium, as in Teichospora and Teichospor-
ella (Miss NicHoLs ’96) and also in Pleospora (BAUKE ’77).

From the above list, selecting the best investigated forms which
have a simple ascocarp, we find Dipodascus, Thelebolus, Gy ;
Sphaerotheca, Erysiphe, Phyllactinia, Ryparobius, Ascobolus,
Humaria, and Monascus. Those having a compound apothecium
are several species of lichens (in which, according to Baur, several
hundred carpogonia in some cases may be present in a single apothe-
cium), Pyronema, Boudiera, and Thecotheus.

JUEL (:02) has studied the nuclear phenomena in Dipodascus.
The sexual organs arise as short outgrowths of two neighboring cells,
each gamete containing several nuclei. After the organs fuse, the
walls between break down and the nuclei of the antheridium pass into
the oogonium, which grows into a single ascus containing a large
fusion nucleus and several smaller nuclei. Although Juet was unable
to make out the details of spore delimitation, he claims that the
appearance of the cytoplasm indicates that the spores are formed by
free cell formation about the descendants of the fusion nucleus,
while the remaining nuclei, which did not fuse in the oogonium, lie
scattered in the epiplasm. The actual process of nuclear fusion was
not observed.

Miss DALE (:03) describes a sexual fusion of gamete cells in
Gymnoascus Reessii and G. candidus. The oogonia and antheridia
are of more or less separated origin. BARKER (:03), IKENO (:03),
KUYPER (:04, :05), and OLIVE (:05) have investigated Monascus.
BARKER’s and OLIve’s accounts differ somewhat from that of IKENO.
These two authors describe the ascogenous hyphae of Monascus

PSE en Oe eee oa ee Pa Ase

See eee

ROSEN cabinet eee eign, 1a ee Re a PE Se

1906] OVERTON—THECOTHEUS PELLETIERI 453

as arising from an oogonium which has been fertilized by an anther-
idium, thus establishing a sexual process for Monascus. They also
hold that the asci arise from the cells of ascogenous hyphae; while
IKENo asserts that there are no ascogenous hyphae, but that uninu-
cleate spore mother cells arise by free cell formation, which in turn
form spores also by free cell formation. KuyPER denies any fusion
of sexual cells in Monascus, mainly confirms IkENo’s observations,
and regards the spore mother cells as true asci.

Two forms closely related to Thecotheus in that they belong
among the Ascobolaceae have been investigated. BARKER (:03, :04)
in two preliminary notes has described the presence of sexual organs
in Ryparobius. The development of the ascocarps was observed
step by step under the microscope in hanging drop cultures. The
archicarp consists of a small coiled oogonium and a slender anther-
idium arising from the next cell of the mycelium, growing out over the
tip of the oogonium, and fusing at the point of contact. Both anther-
idium and oogonium are uninucleate when first formed, but subse-
quently nuclear division occurs in each organ. Nuclear fusion probably
occurs, constituting a regular fertilization, although this process was
not actually observed. Walls are formed, so that the resulting cells
are uninucleate with the exception of the penultimate cell of the
ascogonium, which is sometimes found to contain two nuclei lying
close together. It will be seen that there is great similarity between
Ascobolus and Ryparobius as to the morphology of both the asco-
gonia and the ascocarps. The ascogenous hyphae, however, do not
originate from aay particular cell of the ascogonium, as has been
described for Ascobolus.

CLAUSSEN (:05) has also worked out the morphology of the asco-
carp of a form which he at first believed to be Boudiera hy perborea,

-but which Hennrncs (:03) described as a new species under the

name of B. Clausseni. CAVARA (:05), basing his conclusions upon
CLAUSSEN’s figures, descriptions, and culture methods, believes
that this fungus is not a new species of Boudiera, as HENNINGS has
described, but that it corresponds perfectly to a species of Ascodesmis,
which has been described by VAN TIEGHEM (’76) and later by ZUKAL
(86). Van TrecHem described in detail two species, A. nigricans
and A. aurea. CAVARA believes that the fungus is A. nigricans

454 BOTANICAL GAZETTE [DECEMBER

-Van Tiegh., and that it has been found by him (’8g) in the neigh-
borhood of Pavia. DANGEARD (:03) has also briefly described the
development of A. nigricans, which Cavara fails to note. So far
as I am able to judge from the figures and descriptions of these
authors, I see no reason for doubting that CLAUSSEN’s fungus repre-
sents_a new species of Boudiera, as described by HENNINGS. CLAUS-
SEN grew the fungus on cultures and was able to trace the life history
from spore to spore. He found that the archicarps consisted of
antheridia and oogonia spirally coiled together and borne in groups.
As in Pyronema, the apothecium originates from several pairs of
gametes. The ascogenous hyphae appear to originate from any or
all of the cells of the ascogonium.

The latest work of HARPER (:05), already referred to, traces the
formation of the sexual organs and nuclear fusion in Phyllactinia
corylea in the minutest detail, showing that the ascocarps develop
as the result of fertilization.

BLACKMAN and FRASER (:06) point out that the non-cytological
investigation of several forms has shown that a normal sexual process
is not to be expected in all, and they have therefore undertaken the
cytological investigation of Humaria granulata, a form in which no
antheridium is present. They find that the oogonium develops asa side
branch from multinucleate cells of the mycelium, but that no anther-
idia are formed as described by Worontn (66). The archicarp
consists of a varied number of cells, the apical cell of which is much
swollen and vacuolate, becoming the ascogonium. Investing hyphae
arise from the stalk cells but no antheridia are developed. The
ascogonial cell contains a number of nuclei probably formed by divi-
sion of its primary nuclei. These female nuclei fuse in pairs, thus
constituting what they regard as a reduced sexual process, similar to
what occurs in the development of the aecidium of Phragmidium
violaceum. This vegetative fusion occurs in the ascogonia of various
ages, and-at no definite stage as in Pyronema. These fusion nuclei
pass into the ascogenous hyphae, and on account of their size are
easily distinguished from those of the vegetative hyphae.

RamLow (:06) has shown that the archicarp of Thelebolus ster-
coreus arises as a much twisted uninucleate organ from the uninucleate
cells of the mycelium. No antheridium is developed, but the nucleus

5
3
;
a
:
'
;

1906] OVERTON—THECOTHEUS PELLETIERI 455

of the oogonium divides by successive division until eight free auclei
are formed. Cross walls are then formed in such a manner that
one cell contains two nuclei. This cell is larger and finally develops a
single ascus, as in Sphaerotheca. No reduced sexual fusion, such as
described by BLACKMAN and FRASER, was observed, and RAMLOw

-believes that Thelebolus is strictly apogamous. Although this form

has been placed among the Hemiasci by several earlier authors,
Ramtow from his studies believes it to be a member of the Ascobo-
laceae, as suggested by SCHROETER and REHM.

That a sexual reproduction occurs in the lichens, comparable to
that found in the red algae, as first described by Stant (77), and
confirmed by Borzr (78) for other species of Collemaceae, has been
practically established by the investigations of several later authors.
Although Krappe’s work (’83, ’91) on Cladonia, Baeomyces, and
Sphyridium would indicate that sexual organs were absent in these
forms, yet WAINIO (’90, 97, ’98) claims to have found trichogynes in
very young podetia of Cladonia, which would show that sexual organs
are present. Baur’s work (’98) on C. crispum confirms STAHL’s
observations in every detail. He figures and describes carpogonia
and trichogynes. His work also shows that fertilization is a necessity
to the development of asci. If the carpogonia are not fertilized by
a spermatium, they develop vegetative hyphae; while each cell of
the carpogonium which has been fertilized develops ascogenous
hyphae. The discovery by STAHL and Lrypau (’88) of trichogynes in
Physcia pulverulenta has been confirmed by DARBISHIRE (’99), who
finds a trichogyne and a carpogonium, each cell of which is uninu-
Cleate. The cells of this carpogonium become connected so as to
form a more or less continuous structure. LrypAU (788, ’89) has
also described the presence of trichogynes in several other species
of lichens, but denies that they are sexual organs. In a more recent
work Baur (:o1) finds that Parmelia acetabulum, Anaptychia ciliaris,
Pertusaria communis, and Pyrenula nidia have carpogonia. Anap-
tychia possesses a single carpogonium, while the other forms have the
Carpogonia in groups, thus making the fruit body a compound apo-
thecium. Baur’s opinion is that fertilization occurs by means of
Spermatia combining with the trichogynes. In a still more recent
Work Baur (:04) finds the ascogenous hyphae of Parmelia, Anapty-

456 BOTANICAL GAZETTE [DECEMBER

chia, Endocarpon, Gyrophora, Lecanora, and Cladonia arising from
carpogonia similar to those of Collema, so that these forms also
probably possess sexual organs. Solorina is probably apogamous,
behaving in this respect like Peltigera peltidea and Nephromium as
described by FUn¢sttck (:02), in which trichogynes have disappeared.
SCHULTE (:04) has studied the structure of several species of Usnea.
In U. longissima he claims that the asci do not arise from the asco-
gonia, although several are present. Trichogynes and spermatia
could not be found in U. microcarpa.

The presence of trichogynes, spermatia, and carpogonia similar
to those of the red algae, and also ascogenous hyphae which arise from
carpogonia, all indicate the presence of an undoubted functional
sexual apparatus in the lichens, although the important phenomena
relating to nuclear behavior still remain unsolved.

GUILLIERMOND (:05) has discovered a nuclear fusion accompany-
ing cell fusion in certain yeasts which he holds to be sexual. Conju-
gation of conidia and nuclear fusion take place in the Schizosac-
charomycetes and Zygosaccharomyces just before spore formation,
while in certain other forms (S. Ludwigii, etc.) the same phenomena
occur at the time of spore germination. In the Schizosaccharomy-
cetes and Zygosaccharomyces two cells become connected by a con-
jugation tube in which nuclear fusion occurs. The fusion nucleus
divides immediately and the two daughter nuclei separate, one enter-
ing each original cell, in which a double division occurs to form the
four nuclei of the four so-called ascospores. In certain other yeasts,
such as S. Ludwigii, projections are put out from contiguous spores
in the ascus, fusing to form a canal in which nuclear fusion occurs. A
promycelium is developed from this conjugation tube, which buds
off conidia. GUILLIERMOND considers the phenomena here presented
as the conjugation of isogamous gametes, in the one case before and
in the other case after the formation of the asci. In the one case,
S. Ludwigit, yeast of Johannisberg, and S. saturnus, the sporophyte
with the double nuclear characters is the ordinary vegetative budding
stage of the yeast, while in the other case (Schizosaccharomycetes
and Zygosaccharomyces) this vegetative stage is the gametophyte.

The most recent investigations on the Ascomycetes and rusts indi-
cate an undoubted alternation of generations in these groups. It

_ 1906] OVERTON—THECOTHEUS PELLETIERI ~ 457

will certainly be interesting, therefore, if the yeasts can be shown to
exhibit like phenomena, but apparently these forms need to be further
investigated before alternation of generations can be regarded as
firmly established.

From the above résumé it will be seen that the doctrine of the
sexuality of the Ascomycetes has steadily advanced since DEBARy’s
time, but an immense number of forms remain yet to be investigated
as to the initial stages of the ascocarp. While much investigation
has centered on the sexual apparatus, the study of the development
of the ascospores has by no means been neglected. Within recent
years a considerable literature has been developed relating to the
cytology of the ascus. We are concerned more especially with the
method of spore formation and the phenomena of chromosome
E.

i

EE ae, ee oe en ee ae ee Sg en See hae

teduction, and the literature of this phase of the subject may be sum-
marized as follows:
GJURASIN (’93) first observed mitoses in the ascus of Peziza
vesiculosa, maintaining that the divisions are karyokinetic and that
__ the prophases and anaphases take place inside the nuclear membrane.
__ He discovered well-marked asters but describes no centrosomes. In
the last or third division the spindles are placed at right angles to the
length of the ascus. The asters of these nuclei persist for a remark-
‘ ably long time, and the astral rays, although not connected with the
_ ‘huclei, are folded back over them.
: DANGEARD (’94) in studying very young asci of Peziza vesiculosa
and Borrera ciliaris discovered the two primary nuclei of the ascus,
which fuse to form the large ascus nucleus. Four nuclei appear in
the recurved tip of a young ascogenous hypha. By means of trans-
verse walls the nuclei are so separated that one remains in the end
cell, two in the penultimate cell, and one in the antepenultimate
cell. The ascus grows out from the penultimate cell and the two
nuclei fuse to form the ascus nucleus. This according to DANGEARD
is a true sexual union.
HARPER ('05, ’96, 97 ’99, :00, :05) has made the most thorough
study of the structure and division of the nuclei in a number of Ascomy-
cetes. He discovered and described the réle of the kinoplasmic
fibers in the formation of spores. He first counted the number
Es Of chromosomes in several species. In Pyronema confluens he also

PAIRS tae eS ae

458 BOTANICAL GAZETTE [DECEMBER

observed that there are at first two nuclei in the recurved tip of an
ascogenous hypha, which divide simultaneously by mitosis, thus
forming four. One of each pair of nuclei enters the young ascus,
which arises as an outgrowth of the penultimate cell. These two
nuclei, which in this case are thus shown to be not sister nuclei, fuse
to form the ascus nucleus. In a study of spore formation HARPER
determined and fully described the process involved in the delimitation
of the spores. Each nucleus forms a beak which is connected with
a persistent central body, bearing at its outer end the astral rays.
These rays bend backward and downward, finally coming in contact
laterally and fusing to form a thin membrane, which continues to
grow backward until a focal point is reached, thus completing the
process of spore delimitation. This kinoplasmic membrane cuts the
spore out of a homogeneous mass of protoplasm. He has described
this process in Erysiphe communis, Peziza vesiculosa, Ascobolus jur-
juraceus, Lachnea scutellata, Pyronema confluens, and Phyllactinia
corylea.

BERLESE (’99) has studied spore formation in Tuber brumale,
concluding that the plasma membrane of the spore is formed from the
astral rays. His results on nuclear phenomena agree essentially
with those of GJURASIN and HarPER. MArreE (:03, :04, :05) has
described the nuclear divisions and ascus formation in Galactinia
succosa and several other Ascomycetes, and confirms the method of
spore formation as described by HARPER.

GUILLIERMOND (:03, :04, :05) studied several species with especial
reference to karyokinetic division, the structure of the epiplasm, and
the formation of the asci. He confirms the results of Marre on
Galactinia succosa, finding that the tips of the ascogenous hyphae
are not recurved, but that the terminal cells give rise to the asci.
Wherever spore delimitation was studied it was found to follow the
method described by Harper.

BARKER (:03, :04) in a preliminary study of Ryparobius, a form
whose asci contain more than eight spores, finds that the asci are
formed from the penultimate cells of the ascogenous hyphae which
contain two nuclei, these subsequently fusing to form the ascus
nucleus. He also studied the nuclear divisions and spore formation.
Sixty-four free nuclei are formed, which become regularly grouped

1906] OVERTON—THECOTHEUS PELLETIERI 459

in the peripheral, dense, granular protoplasm of the ascus. Other
scries of divisions usually occur and uninucleate spores are eventually
formed. The details of spore formation have not been described by
BarKER. The description of spore formation in this many-spored form
will be of great value,and BARKER’s results will be awaited with interest.
He is inclined to believe that the whole process of spore formation is
intermediate between typical methods in sporangia and asci.

MAIRE (:05) concludes that in Galactinia succosa, Pustularia
vesiculosa, Rhytisma acerinum, Morchella esculenta, Anaptychia cili-
aris, and Peltigera canina the first division of the ascus nucleus is
heterotypical, and that the second division is homeotypical. In
the prophases of the first division he finds a well-marked synapsis
stage. The asci are formed by two different processes, one of which
is characterized by the formation of a hyphal system sympodially
branched, each cell of which is a synkaryon containing two nuclei
Which divide by conjugate division. The binucleate terminal cells
of these ascogenous hyphae become the asci. He believes that there
is a tendency in the Ascomycetes to form a synkaryophyte analogous
to that of the Basidiomycetes. MArIRE, however, has been unable
to trace these synkaryons back to their first beginnings, which is
highly important. In Galactinia the centrosomes and spindles have
an intranuclear origin, while the polar asters have an extranuclear
origin, developed independently of the intranuclear part. Nuclear
beaks are formed in the process of spore delimitation.

GUILLIERMOND (:05) finds that in Acetabula leucomelas and in
Galactinia succosa the ascogenous hyphae form a series of binucleate
cells, the end cells of which become the asci. Peziza catinus presents
still another method of ascus formation, which he holds to be anal-
ogous to that in P. vesiculosa. The terminal cells of the ascogenous
hyphae are uninucleate, while the subterminal cells are binucleate.
These binucleate <chienien cells bud out a lateral branch to form
the ascus, which grows parallel to the filament, and in which nuclear
fusion occurs to form the ascus nucleus. GUILLIERMOND has studied
the behavior of the chromatin in the asci of Pustularia vesiculosa,
Peziza rutilans, P. catinus, and Galactinia succosa, and believes that
_ the first ascus mitosis is heterotypical, and that the first mitosis is

Preceded by a synapsis stage.

460 BOTANICAL GAZETTE [DECEMBER

FAULL (:05) in a cytological study particularly of Hydnobolites
sp., Neotiella albocincta, and Sordaria jfimicola finds also numerous
cases in which the ascus does not arise from the penultimate cell
of the recurved tip of the ascogenous hypha, as originally described
by DaNncEarD. Such is invariably the case in only eleven out of the
thirty-six species studied. In some species he claims that the asci
bud out from the penultimate cells of the ascogenous hyphae, in
others from the terminal cells, and in a few cases apparently from any
cell. The uninucleate state of the ascus is preceded by a fusion
of two nuclei, which may be sister nuclei. The centrosome and asters
are extranuclear in origin, while the spindles are intranuclear.
Enucleate portions of spores may be cut off, as in Podospora.
FavLt’s description of spore formation is particularly interesting,
as it differs entirely from that described by Harper. The spindle
fibers elongate, bringing the daughter nuclei to the periphery of the
sporeplasm, with their centrosomes in contact with the plasma mem-
brane. The spores are delimited about each nucleus by the differ-
entiation of a hyaline, finely granular protoplasm, which begins at
the centrosome and finally entirely encloses the sporeplasm. The
plasma membrane is subsequently formed from or in this hyaliae
area, and concurrently with this a second membrane is formed in
contact with the first, lining the cavity in which the spore is to lie.
FAULL suggests that the membrane may arise by a cleavage in the
limiting area, caused by its growth and differentiation, together with
a pull on the part of the nucleus. Both plasma membranes are
intimately concerned in laying down the exospore. He can find no
evidence that the astral rays fuse to form a membrane which cuts
out the sporeplasm. FAutt also favors the view which homologizes
the ascus with the zoosporangium of the Oomycetes, as an argument
in favor of the origin of the Ascomycetes from the Oomycetes.

FauLt (:06) also concludes that the ascus of the Laboulbenia-
ceae contains a fusion nucleus which divides by three successive
divisions. The process of spore formation is, as he states, essen-
tially the same as he has described for other Ascomycetes.

In Humaria granulata BLACKMAN and FRASER (:06) find that the
asci are usually developed from the subterminal cells of the recurved
tips of the ascogenous hyphae. In two cases they found asci

1906] OVERTON—THECOTHEUS PELLETIERI 461

developed from the terminal cells of these hyphae, as described by
Marre for Galactinia succosa. These authors have not made a
detailed study of the nuclear phenomena, but believe that spore forma-
tion is essentially the same as described by HARPER.

Ramtow (:06) finds that the single ascus of Thelebolus stercoreus
arises directly from the ascogonium, as in Spaerotheca. The two
primary ascus nuclei fuse, and the resulting nucleus by successive
divisions forms an enormous number of free nuclei. The details of
karyokinesis have not been followed, although he satisfied himself
that the divisions are indirect. The nuclei are evenly distributed
inthe ascus. The phenomena of spore formation were not accurately
determined, but Ramiow, basing his conclusions on the appearance
of the protoplasm, which does not cleave as in the sporangium of the
Phycomycetes, the appearance of an epiplasm, and the position of the
nucleus at one end of the young spore, believes that the process of
spore formation is by free cell formation, just as in Erysiphe.

THE NUMBER OF CHROMOSOMES RECORDED IN ASCOMYCETES.

Plant percent rene Observer Year
Aleuria cerea........... hae 8 Guilliermond 1903, 1904, 190§
Anaptychia ciliaris.......... 4 Dangeard 1903
Anaptychia ciliaris.......... 8 Maire 1904, 1905
Anaptychia ciliaris.......... 8 Guilliermond 1905
Ascobolus furfuraceus....... 8 Harper 1895
Ascobolus furfuraceus....... 4 Dangeard 1903
Ascodesmis nigricans....... 4 Dangeard 1903
End arpon miniatum ...... 4 Dangeard 1903
Erysiphe co Nissen 8 Harper 1900
Galactinia succosa.......... 4 aire 1903, 1904, 1905
Galactinia succosa.......... 8 Guilliermond 1905
Hydnobolites sp............ 40r5 aull 1905
Hypomyces Thiry. 4 e 1905
Morchella esculenta........ 4 Dangeard 1903
Neotiella albocincta......... 6 or 7 a
Otidea onotica............. 8 Guilliermond 1903, 1904
Peltigera canina............ 4 e 1904, 1905
Pevita catinus,.,.....¢.. 12 Guilliermon 1903, 1904
Peziza catinus............. 16 Guilliermond 1905
Peziza rutilans............. 12 jermon
eziza rutilans............. 16 Guilliermond 1904, 1905
Peziza Stevensoniana....... 8 Harper 18
Phyllactinia corylea......... 8 Harper 1905
yronema confluens........ Io Harper Tg00
Onema confluens........ 4 Dangeard 3
Pustularia vesiculosa......... Pi aire 1904, 1905
Pustularia vesiculosay i345 8 Guilliermond 1905
ytisma acerinum......... 4 aire 1904, 1905
Ryparobius Sp. ee 8 (?) Barker 1904
Sphaerotheca castagnei..... 4 Dange te
See kc ees

462 BOTANICAL GAZETTE [DECEMBER

The determination of the number of chromosomes in the ascus as
well as in other cells is of the highest importance, as it will indicate
the real nature of alternation of generations in the higher fungi.
Since the chromosome number has been determined by several
authors for a number of species of Ascomycetes, it may prove useful
to summarize the results. (See the foregoing table.)

That there is considerable difference of opinion as to the chromo-
some number even in the same species of some Ascomycetes is evi-
dent from the above table. In Ascobolus and Pyronema HARPER
finds eight and ten respectively; while DANGEARD claims that there
are four in both species. GUILLIERMOND and Marre have established
the number eight for Anaptychia; while DancEaRD claims four
for this species also. Marre counts four chromosomes in Galactinia
succosa and Pustularia vesiculosa, while GUILLIERMOND claims that
there are eight in each of these forms.

From the above résumé it seems perfectly evident that no such
hypothesis as that the chromosome number four is general among the
Ascomycetes, as DANGEARD imagines, can be maintained. In this
group, on the contrary, judging from the above facts, related species
may vary in their respective chromosome numbers, just as has been
found to be the case in many of the higher plants.

In a recent paper Marre (:05) criticizes GUILLIERMOND (:05)
for saying that he maintains that there are probably four chromosomes
in all Ascomycetes, but admits that he and DancEarD have formu-
lated practically parallel hypotheses on this point. DANGEARD
(:03), however, distinctly refers this hypothesis to MAtRE (Séance
de la société mycologique de France tenue & Poitiers ea Octobre,
1903), and says “‘ Cette découverte a été faites simultanément et d’une
maniére indépendante par Marre et nous: elle offre, semble-t-il,
toutes garanties de certitude.” It appears from these facts that
Mair has the responsibility of having first made the claim made by
DANGEARD, but which Marre now attributes to him. It is per-
fectly plain that no basis for such a hypothesis exists, a fact which
MAIRE apparently fully recognizes.

Since DANGEaRD first described the asci in a number of forms as
arising from the cell next the terminal one, several deviations from
this type have been reported. That no such regular process of ascus

a? a

Se | ey Cree ee ee

PE ee a ee Pe

1906] OVERTON—THECOTHEUS PELLETIERI 463

formation obtains in general in the whole group of Ascomycetes, or
even in nearly related genera, is clearly evident from a study of the
more recent cytological investigations, especially those of Marre,
GUILLIERMOND, and Fauit. In the following résumé no pretense
of absolute completeness is made.

We may note first those very simple forms which have sometimes
been classed together as Hemiasci, though in most cases, as KUYPER
shows, the types are plainly not closely related. The genera Ascoidea
(Popra ’99), Protomyces (SAPPIN-TROUFFY ’97, PoPTA ’99), and
Taphridium (JuEL :02) possess a septate mycelium with multi-
nucleate cells, from which the sporangia arise directly without the
intervention of sexual organs. The hyphal cells of Protascus (DAN-
GEARD :03) also give rise directly to the asci. Sexual organs are
present in Dipodascus (JUEL :02) and Eremascus (ErDAM 83),
and the fertilized oogonium forms a single ascus. Monascus (BARKER
:03, OLIVE :05) apparently forms a branched ascogenous hyphal
system, each cell of which is able to produce an ascus. The hetero-
geneity of these forms is evident by the fact that the asci arise
directly from an oogonium, from hyphal cells, or from the cells of
ascogenous hyphae.

n some yeasts the conidia become transformed immediately after
nuclear fusion into so-called asci, as in Schizosaccharomyces and
Zygosaccharomyces, while in others the conidium is transformed
directly into the ascus and fusion comes later, as in S. Ludwigit
(GUILLIERMOND :05).

In the Exoasci the binucleate cells of the mycelium are transformed
immediately into a single ascus, as in Exoascus dejormans (DANGEARD
94) and Taphrina (SADEBECK ’93, IKENO :OT, :03). Among the
Gymnoascaceae, G. Reesii and G. candidus (BARANETZEY °72, Emam
"83, DaLE :03) have their asci arising from the end cells of a series of
short ascogenous hyphae. If CLAUSSEN’S (:05) Boudiera is really
Ascodesmis nigricans, as CAVARA (:05) believes, and if Ascodesmis
belongs among the Gymnoascaceae, then we have a form in this group
whose asci arise from the penultimate cells of the recurved tips of
the ascogenous hyphae.

rable variation in the method of

The Perisporiaceae show conside
ascus formation. The early works of DEBARY and others may be

464 BOTANICAL GAZETTE [DECEMBER

passed over, as the methods used by them were not sufficiently deli

cate to enable them to determine the exact method of ascus formation.
The end cells of ascogenous hyphae described by DEBary for Euro-
tium, for example, may as well represent subterminal cells. In the
mildew, Erysiphe communis (HARPER ’96), the end cells of the asco-
genous hyphae may develop the asci. This is also the case in Phyl-
lactinia corylea (HARPER :05), but asci may also be formed as lateral
branches of intercalary cells. In Sphaerotheca castagnei (HARPER
’95) and S. humuli (BLACKMAN and FRASER :05) the oogonium
develops into an ascogonium of five or six cells, of which the penulti-
mate one grows into a single ascus. In this genus there are no asco-
genous hyphae, unless we accept the interpretation of BLACKMAN and
FRASER that the ascogonium is a single ascogenous hypha, whose
penultimate cell develops an ascus in the manner described by DAN-
GEARD. In Anixia spadicea (FAULL :05) the asci spring from any
cell of the ascogenous hyphal system.

In the Tuberaceae, 7’. melanos permum (DANGEARD ’94, GUILLIER-
MOND :04) has its asci arising as described by DANGEARD; while
Genea hispidula (FAULL :05) shows a marked variation from this
type. In this form the ascus grows out from a curved terminal cell.
FAULL suggests that perhaps the only difference between this and
the other type is the lack of a cross wall cutting off the uninucleate
hyphal tip.

Among the apogamous Pyrenomycetes, such as Teichospora
trimor pha, T. aspera, T. nitida, and Teichos porella sp. (Miss NICHOLS
’96), a uninucleate ascus arises from a single central cell of the peri-
thecial mass. Hypomyces Thiryanus (MaAIRE :05) follows the
method described by DANGEARD; while in Podospora ascerina, P.
setosa, Sordaria fimicola, and S. humana (FAuLL :05) the asci arise
from a curved terminal cell of an ascogenous hypha. In Phyllachora
graminis (FAULL :05) the ascus arises from a curved cell of the tip
without the formation of a uninucleate tip-cell.

The Discomycetes are described as showing the greatest uniformity
in the method of ascus formation, which may perhaps be due to the
fact that more careful work has been done upon them. All the
following forms have their asci formed in the manner described by
DANGEARD (’94) for Peziza vesiculosa: Borrera ciliaris, Acetabula

1906] OVERTON—THECOTHEUS PELLETIERI 465

calyx (DANGEARD ’94), Peziza Stevensoniana, Ascobolus furfuraceus
(HARPER ’95), Lachnea scutellata, Pyronema confluens (HARPER :00),
Aleuria cerea (GUILLIERMOND :03, :04), A. amplissima, and A.
olivea (GUILLIERMOND :04), Peziza catinus, P. venosa, P. rutilans
(GUILLIERMOND :04), Ascobolus marginatus, Otidea onotica (GumL-
LIERMOND :03, :04), Acetabula vulgaris, Pyronema confluens, Ciboria
echinophila, Bulgaria inquinans, Guilliermondia saccabaloides (Gut-
LIERMOND :04), Peziza sp. (FAULL :05), Ryparobius sp. (BARKER
03, :04), Neotiella albocincta, Acetabula sp., Pseudoplectania sp.,
(FAULL :05), Boudiera Clausseni (CLAUSSEN :05), Peziza vesicu-
losa (MaIRE :05), Thelebolus stercoreus (RAMLOW :06), Humaria
granulata (BLACKMAN and FRASER :06), Thecotheus FPelletieri
(OVERTON :06). Several variations from the type described above
also occur among the Discomycetes. Galactinia succosa (MAIRE
03, :05, GUILLIERMOND: 03, :05), Acetabula leucomelas (GUILLIER-
MOND :03, :04, :05), Acetabula vulgaris (MATIRE :03) have their
asci arising from binucleate terminal cells. GUILLIERMOND (:03) also
found that Pustularia vesiculosa occasionally has its asci arising in
alike manner. Peziza catinus and P. vesiculosa (GUILLIERMOND
:05) occasionally have the asci arising from the subterminal cells
of the ascogenous hyphae whose tips are recurved. Acetabula
acetabulum (GUILLIERMOND :03) has binucleate cells formed in the
curved tips of the ascogenous hyphae which do not form the asci, but
give birth to a series of two, three, and four cells, of which the
terminal ones produce the asci. In Discina venosa (FAULL :05) the
ascus arises from a curved terminal cell. In Urnula cratertum
(FAULL :05) the ascus may spring apparently from any cell what-
ever. In Humaria granulata (BLACKMAN and FRASER :06) the ascus
occasionally arises from the terminal cell.

A number of the Helvellaceae have been studied, which also show
great variation in the mode of ascus formation. Helvella ephippium
(DaNcEaRD ’ 94), Morchella esculenta (DANGEARD ’94), Helvella sul-
cata, H. elastica, H. crispa (GUILLIERMOND :04), Morchella escu-
lenta, M. conica, Helvella astra, H. lacunosa, H. elastica (FAULL
‘05) have their asci formed from the penultimate cells of the
Tecurved tips of the ascogenous hyphae, in the manner described by
DaNGEarD for Morchella. In Geoglossum ophioglossoides, G. hir-

466 BOTANICAL GAZETTE [DECEMBER

sutum, Geoglossum sp., Verpa conica, Gyromytra sphaerospora, Lepto-
glossum luteum, Leptoglossum sp., Mitrula phalloides, Leotia lubrica, L.
chlorocephala (FAULL :05) the ascus grows out from the terminal
cell, and no uninucleate end cell is cut off. In Verpa bohemica (FAULL
:05) is found the very greatest variability; the asci appearing as out-
growths of a terminal cell, or from a second, third, or even fourth cell
from the tip.

The lichens Anaptychia ciliaris (DANGEARD :03), and Peltigera
canina (MarRE :05) have their asci regularly formed according to
DANGEARD’s method; but Anaptychia ciliaris (MAIRE :05) appar-
ently develops its asci from the subterminal cells of the ascogenous
hyphae, while the tips, according to MAIRE, may continue develop-
ment. Baur (:01, :04), although he does not describe the method
of ascus formation, figures ascogenous hyphae which are recurved
in Pertusaria communis.

In the foregoing I have endeavored to group our knowledge of
the various methods of ascus formation according to the natural
classification of the forms investigated, in order that the significance
of the variation described may be more apparent. It is the nuclear
history which is theoretically most interesting, and is thus most essen-
tial to determine the relative ancestry of each of the nuclei which fuse
in the ascus. This has been done for very few forms as yet. In
Pyronema, HARPER (:00) has been able to trace the origin of the two
primary nuclei of the ascus, in a case in which the tips of the ascogen-
ous hyphae at first contain two nuclei. These divide by simultaneous
division. Of the four nuclei thus formed, one lies in the terminal
cell, and two, which are not sister nuclei, in the subterminal cell which
becomes the ascus.

Thecotheus belongs to that group of the Discomycetes (Ascobo-
laceae) whose small fruit bodies are nearly always found growing
freely on dung. The species in question occurs on horse dung.
It was found on cultures which were old and partly dried up in
the Botanical Laboratory of the University of Wisconsin. These
cultures were kept running, yielding an abundant supply of material
during the progress of this investigation. The fungus has since been
found free in nature. The apothecia are very small, about o.5™™ in
diameter and 0.25™™ high, of a white or yellowish color. When

ee ee he ee ee ee eee

ii gies aaa ee Se Teale See NO en nN ner Mee pT ee RES a MEE ee ge mA Seay ot, Sa ee OP — @

1906] OVERTON—THECOTHEUS PELLETIERI 467

wet they are therefore plainly visible to the naked eye. A distincy
thin excipulum, or lateral boundary of vegetative hyphae, surrounds
the hymenium (fig. 3). This excipulum is densely covered with
short, blunt ends of protruding vegetative hyphae, which give a hairy
or warty appearance to its surface. The sterile tissue of the secondary
mycelium extends outward and downward to form a pseudo-parenchy-
matous skirt-like structure, which also extends along the substratum
beneath the hypothecium. This lower layer becomes adjusted to
the irregularities of the substratum, from which numerous hyphae
enter the fructification. The equilibrium of the whole fruit body is
maintained by means of this much broadened pseudo-parenchy-
matous base (fig. 3).

The apothecia are at first globular or cylindrical, later becoming
broadened, discoid, and somewhat biscuit-shaped (fig. 2). The
asci are roughly cylindrical in form, about 220 35H, their greatest
diameter being near the top. Each ascus contains thirty-two ellip-
soidal, slightly colored spores, each about 17.5% 28#, which are
discharged through a small terminal pore. This pore is at first
covered by a small cap or operculum, bounded by a thickened ring in
the wall of the ascus where the cover breaks off (fig. 16). The asci
develop from the subhymenium successively; each fruit body thus
contains asci and spores in all stages of development. Numerous long
and slender septate paraphyses, about 360 long, arising from the
hypothecium, are thickly packed among the asci. At the surface
each paraphysis has a somewhat swollen protruding tip (figs. 2, 3)-
The mature spore contains a single nucleus in a mass of very densely
granular protoplasm (fig. 15). The thin, very pale exospore is corru-
gated on its outer surface, much like many other spores of the Asco-
bolaceae. There is a passage through this exospore at each end,
as well as through the thick hyaline endospore, to form what is appar-
ently a terminal germinal pore. The spores are not shot out of the
asci, but appear to be squeezed out by turgor, together with the
lateral pressure exerted by the turgor of the neighboring asci and
paraphyses. They are to be found as a dust on the surface of the
apothecium, often adhering in masses. Possibly in consequence of
the smallness of the terminal aperture of the ascus the spores are not
projected or discharged violently. This condition is not general

468 BOTANICAL GAZETTE [DECEMBER

among other forms of the Ascobolaceae, in most of which the spores
are projected for some distance through the terminal pore of the ascus.

Modifications of the usual strengths of Flemming’s chromacetic
osmium fixing fluids were exclusively used in the preparation of the
material. Portions of the substratum upon which apothecia grew
were removed and dropped into the fluids. Beside the mature fruits
many younger stages were thus obtained. The sections were stained
with safranin gentian-violet orange-G combinations and also with
Heidenhain’s iron-alum haematoxylin. The sections were cut 5-10 #
thick.

HARPER (’95, ’96, :05) has shown that the ascogonia of the mil-
dews consists of a much curved row of cells, each of which contains
a single nucleus, with the exception of the penultimate cell, which
contains two or several nuclei, and which forms the ascus in Sphaer-
otheca, out of which grow the ascogenous hyphae in other forms.
BARKER (:03, :04) also observed the same kind of ascogonium
in Ryparobius; while CLaussEN (:05) finds several such ascogonia
in Boudiera. The youngest ascogonium which I have thus far
observed in Thecotheus consisted of a row of several cells which were
already multinucleate (jig. 1). HARPER (’96) figures and describes
perforations in the cross walls in the ascogonium of Ascobolus con-
necting the adjacent cells: One of the cells of the row is larger.
It is from this particular cell that the ascogenous hyphae arise, and
out of which the nuclei enter the ascogenous hyphae from it and
the neighboring cells. As soon as the ascogonia become empty
they undergo disintegration. BARKER (:04) finds each cell of the
row in Ryparobius at first uninucleate and then binucleate or occa-
sionally quadrinucleate. From the cells of the row the ascoge ous
hyphae delevop. He does not distinctly say that they develop from
any particular cell of the ascogonium. CLAUssEN (:05) finds that
the gametes of Boudiera contain several nuclei, which however fuse
in pairs in the oogonium. Several walls are formed, so that the
resulting ascogonium consists of a row of several cells from which
the ascogenous hyphae arise. Thecotheus agrees with Ryparobius
and Boudiera in that the ascogenous hyphae do not arise from any
single cell of the ascogonium, but from any or all of them (jigs. 1 and
2). The youngest ascogonia which I have been able to find were

1906] | OVERTON—THECOTHEUS PELLETLERI 469

already multinucleate, some containing as many as a dozen nuclei,
each much larger than those of the vegetative cells. Fig. 1 shows
a young fruit body with sections of several ascogonia, each of whose
cells are multinucleate. No connections between the adjacent
cells could be observed.

Unlike Ryparobius and like Boudiera, Thecotheus has a com-
pound fruit body. Fig. r represents a section of a young ascocarp,
in which several ascogonia are present. One ascogonium, composed
of several multinucleate cells, is shown, which resembles in shape the
ascogonium of Ascobolus. In the same section, surrounded by the
same investment of vegetative hyphae, may be seen also sections of
several other ascogonia. These ascogonia are always closely inter-
woven, so that they are cut in different planes. Other views of the
same ascogonia appear in adjacent sections of this ascocarp.

Concurrently with the development of ascogenous hyphae, invest-
ing vegetative hyphae encircle the ascogonia, the young ascogenous
hyphae, and the asci. This condition can be seen in fig. 2. Rem-
nants of the ascogonia are still plainly visible, and the branching
ascogenous hyphae can be seen to contain several nuclei, each with
a single nucleolus. The nuclei of the ascogenous hyphae are from
three to four times as large as those of the paraphyses, making them
therefore easily distinguishable. Each cell of the vegetative tissue
contains several nuclei. I have been unable to find any regular
series of binucleate cells.

The developing ascogenous hyphae are profusely branched, pur-
suing such irregular paths that it is impossible to follow their course
for any great distance. Transverse longitudinal and oblique sections
appear in the preparations, which are only mere fragments of the
whole system (jig. 2). From fig. 2, however, it is plain that the
ascogenous hyphae develop considerably before transverse septa are
put in. The nuclei are especially abundant near the tips of the
branches. At the time the cell division is complete, the tips of the
branches of the ascogenous hyphae are bent backward as they push
upward among other branches and paraphyses. The terminal cell
is uninucleate, while the subterminal cell is binucleate. The nuclei
of these branches can be seen to be considerably larger than those
of the ascogonium (fig. 4). From these binucleate subterminal cells

47° > BOTANICAL GAZETTE [DECEMBER

the asci develop. So far as I have been able to observe, asci were
never developed from the terminal cell, or from the third cell from
the tip, although either condition may possibly occur. Thecotheus
certainly does not contain a system of ascogenous hyphae, each cell of
which is a synkaryon, as described for Galactinia and Pustularia
vesiculosa.

In Thecotheus the subterminal cell of an ascogenous hypha
arches up to form the young ascus. The two nuclei apparently fuse
to form the ascus nucleus (jig. 4). The young club-shaped ascus
is filled with a dense finely granular vacuolated protoplasm, in which
are situated numerous deeply staining extranuclear granules, prob-
ably the metachromatic granules of GUILLIERMOND (:03), which
have also been observed and described by other authors. The
fusion nucleus greatly enlarges as the ascus grows, thus maintaining
a definite nucleo-cytoplasmic relationship, as described by HARPER
(:05). Within the nucleus chromatic filaments are organized, which
give the appearance of a loose spirem. Division stages were not
observed, but, so far as I have been able to find, the nuclear structures
are essentially the same as have already been many times described.

The young ascus, which elongates rapidly, crowding up into the
hymenium, is somewhat broadened at its tip, gradually narrowing
toward the base. The protoplasm, packed in the tip, is coarse and
granular (fig. 7). A spore region is organized about the nucleus. A
large region, in which the protoplasm is very foamy, is present both
above and below the central denser sporeplasm. The ascus increases
still more in size, the denser regions at the apex and about the nucleus
becoming still more sharply separated by the large vacuolated space
(fig. 8). A peripheral layer of denser protoplasm connects the apical
and central regions. The distinction of central and apical regions
and the two large vacuolated spaces with foamy protoplasm persist
throughout the process of spore formation (figs. 8-12). The primary
ascus nucleus divides rapidly by three successive divisions to form
eight free nuclei. During these divisions there is a gradual decrease
in the size of the nuclei, as has also been observed in other asci. In
jig. 10 it will be seen that each of the eight nuclei are very small
compared with the nuclei represented in figs. 7 and 8. From the
abundant stages found in the conditions represented in fig. ro, I am

1906] OVERTON—THECOTHEUS PELLETIERI 471

inclined to believe that there is a pause before further divisions occur
and a growth period of these eight nuclei. Not only do the nuclei
increase in size before dividing, but the asci also lengthen very much
and the protoplasm becomes still more vacuolated and foamy (jig. 11).
Perhaps this increase in size of the nuclei is also correlated with the
increase in the amount of cytoplasm in the ascus. Eventually each of
these eight nuclei divides to give sixteen free nuclei, no spores being
yet delimited (fig. rz). In jig. 11 each nucleus is about as large as
one of the daughter nuclei in fig. 8. These nuclei certainly show a
marked increase in size over those of fig. 10. It will also be observed
that the nuclei are irregularly arranged in the central region of the
sporeplasm. Each of these sixteen nuclei undergoes still another
division, resulting in thirty-two free nuclei being found in the ascus.
No figure representing this thirty-two nucleate stage has been drawn,
although the nuclei were seen in the preparations. ig. 6 represents
a portion of such a stage. The nuclei here are also very much
smaller than in jig. 71.

In Ryparobius BARKER (:03, :04) finds that the number and
size of the spores vary in different asci. More than two hundred
were normally found in a single ascus, but as few as sixteen have
been seen. In Ryparobius successive nuclear divisions occur
rapidly, until sixty-four free nuclei are formed. These become
regularly grouped in a dense granular mass of protoplasm around the
periphery of the ascus. Other series of divisions now usually occur,
and eventually uninucleate spores are formed. In Thelebolus (RAM-
Low :06) many nuclei arise in the ascus, about each of which a spore
is delimited, as described by HARPER.

In Thecotheus the spores are delimited from the homogeneous
central portion of the cytoplasm immediately after the formation of the
thirty-two nuclei. So far as I have been able to observe, the entire
process of spore delimitation is accomplished by means of the kino-
plasmic fibers which form the astral radiations of the central body.
The nucleus becomes pointed or beaked, bearing a central body at its
outer end, from which the kinoplasmic radiations extend (fig. 6).
The chromatin lies freely in the nuclear cavity, apparently connected
with the central body. The process of spore delimitation si, ones
ently precisely like that described by Harper for Erysiphe communis,

472 BOTANICAL GAZETTE [DECEMBER

Lachnea scutellata, Pyronema confluens, and Phyllactinia corylea.
As soon as the beak has reached a certain length, which is compara-
tively short in Thecotheus, these kinoplasmic fibers bend downward
and grow backward over the nucleus, fusing laterally to form a con-
tinuous plasma membrane, which separates the cytoplasm of the
spore from that of the epiplasm. The nuclear beak is withdrawn
and a somewhat pointed nucleus remains in the young spore (jig. 6),
which gradually resumes the spherical shape of a resting nucleus.
Although the process of spore delimitation is not easily followed in
Thecotheus, I am convinced that it is essentially the same as HARPER
has described for other Ascomycetes. I have also had an oppor-
tunity to compare my own preparations containing this stage with
those of HARPER on Erysiphe and Lachnea, which objects he found
most favorable for study. I can see no essential differences in appear-
ances. The nuclear beaks do not have any special orientation or
relation to the plasma membrane, as has been figured and described
by certain authors for other forms. The beaks may lie at any angle
during the process of spore delimitation.

BARKER (:04) believes the process of spore formation in the
many-spored asci of Ryparobius to be unlike that in the typical
ascus. “The protoplasm passes through a series of characteristic
changes during the development of the ascus, and the whole process
of spore formation seems to be intermediate between typical methods
in sporangia and asci.” We shall await BARKER’s completed account
of the spore formation in this form with great interest. We have
seen that the method of spore delimitation in the many-spored asci
of Thecotheus is exactly similar to that found in typical eight-spored
asci. As noted in another connection, FAULL entirely dissents from
the method of spore formation as described by HARPER. I have been
unable to discover in Thecotheus the presence of hyaline zones in
connection with which cleavage takes place to delimit the spore-
plasm from the epiplasm as described by Fautt, and I am certain
that no such method of spore formation exists in Thecotheus.

Fig. 6 represents a spore in the process of delimitation as described
above. In the same figure a very young spore is also shown, which
has its delimiting membrane already formed and the nuclear beak
withdrawn. It will be observed that the sporeplasm is nearly like

1906] OVERTON—THECOTHEUS PELLETIERI 473

the surrounding epiplasm, perhaps slightly more dense and gran-
ular. No particular granular area is present. It is simply a portion
carved out of the homogeneous cytoplasm in which the nucleus is
situated by means of a delimiting kinoplasmic membrane. In jigs.
12a-12¢ slightly older spores are shown. They are arranged in the
form of a hollow cylinder around the wall of the ascus. About five
young spores are arranged vertically along the ascus walls in any one
plane. Fig. r2a represents a median longitudinal section of the ascus;
jigs. 12a and 120 are slices off the same ascus.

BARKER (:03) found that the numerous nuclei in the asci of
Ryparobius became arranged in the form of a hollow sphere just
beneath the wall of the ascus before spore delimitation. Each asco-
spore when completely formed, therefore, has one end toward the
center and the other toward the ascus wall, the resulting arrange-
ment of the spores thus being radial. In Thecotheus the nuclei, as
noted above, are not arranged radially, but in the form of a hollow
cylinder about the wall of the ascus, in a denser peripheral layer
of the epiplasm. The resulting spores, therefore, have their long
axes parallel to the wall of the ascus. In this respect Ryparobius
and Thecotheus are essentially different. Due to this peripheral
arrangement into a hollow cylinder, the spores are forced to occupy
considerable space in the ascus, some being pushed up near the tip.
The epiplasm is at this time everywhere much more vacuolated than
in earlier stages, and the ascus is exceedingly turgid and swollen
(figs. 12a-12¢.)

In jig. 12a the spores can be seen to show no sign of an exospore
or endospore. DEBary (’63, ’64) thought that the exospore was laid
down upon the surface of the spore from the epiplasm, which explana-
_ tion seems to have gained rather widespread acceptance. The exact
method of exospore formation needs investigation. FAULL (:05) be-
lieves that two membranes are formed, one beiag the plasma-membrane
of the spore and another formed concurrently with this, which lines
the cavity in which the spore is to lie. These membranes occupy the
positioa of the hyaline zone described above. The spore wall is sup-
posed to be laid down between the membrane bounding the epiplasm
and the plasma membrane of the spore. Fautt suggests that both
membranes are perhaps active in the formation of the spore coats.

474 BOTANICAL GAZETTE [DECEMBER

According to my own observations, the process of the formation
of the spore coats does not agree with the account of FAuULL (:05)
Fig. 13 shows a young spore which has grown somewhat beyond
those found in figs. 12a-12c. The limiting membrane is not per-
ceptibly thickened, showing in sections as an even unbroken line.
Just inside this membrane, however, the endospore is seen to be but
slightly differentiated from the sporeplasm, being much less vacuo-
lated but more hyaline and granular. A more or less distinct bound-
ary is present between the endospore and the sporeplasm. Exactly
how the endospore is formed I am at present unable to state, unless it
is laid down by the original plasma membrane, which has gradually
withdrawn, secreting the substance of the spore coats as it recedes.
Finally, the endospore becomes still more granular and hyaline
as the spore develops (fig. 14). The outermost portion of the
hyaline granular area constitutes the éxospore. In fig. 14, which is
not so highly magnified as jig. 13, the central portion of the spore-
plasm is highly vacuolated. The nucleus of the spore lies in the
center of this mass of protoplasm. The irregularities on the exo-
spore may be due to fixation. Lines are developed on the surface
of the spore, finally producing an irregularly branched system of
elevations and ridges much like that found on the spores Ascobolus.
Fig. 15 represents a mature spore. The two germinal pores, one at
either end, are present, passing through the spore coats. ‘The mature
endospore is very granular and highly refractive. The inner proto-
plasm, bounded by the plasma membrane, is still uninucleate but
densely granular. Smaller vacuoles have entirely disappeared. In
some mature spores two large spherical oil drops are present, one at
either side of the nucleus, but not regularly so. Fig. 15 is typical.

As the asci dry out, the walls become thickened and hyaline.
Fig. 16 shows the upper portion of a nearly mature ascus, at the
apex of which is the cap or operculum in the process of formation.
A thickened ring in the ascus wall is formed below the operculum.
The mature spores are probably discharged through this terminal
pore by the turgor of the ascus and the lateral pressure of other asci
and paraphyses. Although several attempts were made to germinate
these spores in various sorts of media, I have thus far been unsuccess-
ful. Perhaps it may be necessary for them to pass through an ali-

1906] OVERTON—THECOTHEUS PELLETIERI 475

mentary tract or to be naturally or artificially partly digested before
germination will occur, or perhaps the spores tested may not have
been mature.

I have shown that ascogonia are present from which the asci
arise, although I have been unable to find the earliest stages of these
organs in Thecotheus. Since in the forms in which sexual organs do
exist, as described by several investigators, an ascogonium arises as
the result of nuclear and cell divisions from a fertilized oogonium, I
think it practically certain that such oogonia exist in Thecotheus.
Since the ascogonia are in groups, several being present in each young
ascocarp, it is also safe to conclude that the fruit bodies arise as the
product of multiple sex organs, just as in Pyronema and Boudiera.
Thecotheus, therefore, is another example of a form among the -Asco-
bolaceae with a compound apothecium.

In Thecotheus the asci are developed from the penultimate
cells of the recurved tips of the ascogenous hyphae, and they are
at first binucleate, later becoming uninucleate in the usual manner.
There is apparently no tendency here toward the condition described
by Marre and GurILireRMOND, wherein a system of binucleate cells
are formed, as in Galactinia, corresponding to the synkaryophyte
in which a long series of binucleate cells occur, the nuclei finally
fusing in the basidium, as in the Basidiomycetes and rusts. MAIRE
claims to have found that these binucleate cells of the ascogenous
hyphae originate from hyphae of the subhymenium, whose cells are
multinucleate. The first cell arising from these subhymenial hyphae
- contains two nuclei, which divide by a conjugate division, giving rise
to a series of branching synkaryophytic hyphae, which eventually
form the asci. This branched, ascogenous hyphal system MAIRE
compares to the hyphal system which gives rise to the basidia in the
Basidiomycetes. Although Matre and GUILLIERMOND have found
this system of ascogenous hyphae in certain forms, it still remains
and is of the highest importance to determine how the ascocarps
originate in these forms. If, as HARPER (:05) suggests, the condition
found in Pyronema, and still more advanced in Galactinia and Pustu-
laria vesiculosa, could work back until the egg cell was reached, an
apogamous condition might result, such as is now found in the Hymen-
omycetes (Miss NicHots :04), and the nuclear fusion in the ascus

476 BOTANICAL GAZETTE [DECEMBER

might have acquired secondarily a sexual significance. Thecotheus
with its ascogonia, and presumably also still earlier oogonia, shows no
tendency towards this condition. Ihave been unable to find binucleate
cells either in the paraphyses, in the mycelium, or in any of the vegeta-
tive cells of this fungus, and am sure that Thecotheus does not possess
anything comparable to the synkarophyte of the Basidiomycetes.

The main problem relating to the asci at present is whether they
are merely eight-spored sporangia or spore mother cells correspond-
ing to those of the higher plants, and on this point the method of
spore formation in a polysporous ascus should throw much light.
As noted previously, I have confined my attention principally to
Thecotheus on account of the abundance of this apparently very
favorable form. The possibility that such asci might show transi-
tional conditions leading over to those found in the sporangia of the
lower fungi is very suggestive, and, as noted above, BARKER believes
that in the asci of the nearly related genus Ryparobius he has found
such transitional forms, although RAmtow believes the ascus of
Thelebolus shows no such sporangial characters. The distinction
between typical sporangia and typical asci seems to be sharply drawn.
In the sporangia of Sporodinia and Pilobolus Harper (99) has
found that spore formation is by a process of progressive cleavage
by means of furrows, either from the surface of the protoplasm or
from vacuoles of the mother cell. The nuclei during the cleavage
are in a resting stage and are not concerned in the process. Thus
the formation of an epiplasm is precluded. Harper has described
the process of cell formation in Synchitrium decipiens, Pilobolus -
crystalinus, and Sporodinia grandis; while SwINGLE (:03) has
observed the same process in the sporangia of Rhizopus nigricans and
Phycomyces nitens. HARPER has pointed out that this process is not
one of free cell formation in the sense in which the term is used for
free cell formation in the ascus, in which the cells lie free in the mother
cell included in the so-called epiplasm. He also concludes that these
two very divergent methods of cell formation in asci and sporangia
make it impossible to assume any close relationship between these
two structures, and this difference is thus made an argument against
the homology of the sporangium of the Phycomycetes and the ascus of
the Ascomycetes.

1906] OVERTON—THECOTHEUS PELLETIERI 477

Although attempts have recently been made to discredit HARPER’S
results on the method of free cell formation in the ascus, no very
convincing evidence has been brought forward to show that it is more
like that in the sporangium. JuEL (:02) in his work on Taphridium
seems to think that HARPER has placed too much stress on the action
of the kinoplasmic fibers as one of the chief distinguishing character-
istics of the process, saying: “ Vorlaiifig konnen wir nicht die Rolle
des Kinoplasmas bei der Zellbildung zur nota characteristica der
freien Zellbildung machen, sondern miissen diesen Begriff in der
herrkémmlichen Weise auffassen.”” Apparently JuEL has failed
to comprehend the essence of HARPER’s definition.

FAULL (:05) does not believe that the methods of spore formation
in the ascus and sporangium are so different as to prevent assumption
of their homology. He favors the view that homologizes the ascus
with the zoosporangium of the Oomycetes, as an argument in favor of
the origin of the Ascomycetes from the Oomycetes. The most
complete account of cell formation in the zoosporangia of the Oomy-
cetes is that given for Saprolegnia and Achlya, although the behavior
of the nuclei has not been thoroughly enough studied.

The earliest workers in the study of spore formation were influenced
by their a priori views on the cell theory as a whole, and NAGELI used it
to support his doctrine that new cells are regularly formed by so-called
free cell formation from old ones. PRINGSHEIM (’51) believed that
spores were formed by simultaneous and not by successive biparti-
tions of the protoplasm, being completely bounded off before the
appearance of a cellulose wall. BiscEeN (’82) in his description of
spore formation in the sporangium of the Phycomycetes believed that
cleavage is due to a simultaneous formation of cell plates, which break
down, being later formed again to separate the spores. BERTHOLD (’86)
Studied oogonia, but assumed that the process in oogonia and spor-
angia are alike. The peripheral layer of protoplasm which surrounds
the central vacuole forms dense rounded masses about definite centers,
which constantly increase in size, protruding gradually into the
central vacuole. Finally the masses separate and round up, later
swelling up so as to become pressed together and flattened. Finally
these masses again round up, forming definite eggs or swarm spores.
BERTHOLD claims that the position of the spores is predetermined by

478 BOTANICAL GAZETTE [DECEMBER

centers of attraction, about which the protoplasmic lining of the walls
is collected. ‘The whole process is a form of free cell formation, in
which the entire protoplasm is utilized, without involving the forma-
tion of a periplasm. He holds, therefore, that the sporangium of
the Saprolegniaceae represents an advance over forms in which peri-
plasm is formed. The sporangium is differentiated into central
vacuole and peripheral protoplasm, and is perhaps a stratified struc-
ture in itself, whose polarity is determined by the position of the nuclei,
which in turn influence the position of the spores, as has been pointed
out by HARPER (’99).

According to the work of RorHErt (’88), Hartoc (’88), Hum-
PHREY (’92), TRow (’95), and Davis (:03), the sporangium is multi-
nucleate when cut off, the nuclei lying scattered in the peripheral
layer of protoplasm. Davis practically confirms the account of the
earlier authors. The uninucleate spores originate by means of clefts,
which proceed from the central vacuole of the sporangium to the per-
iphery, dividing the protoplasm into polygonal areas. The spores
are later formed from these uninucleate areas. There is no mitotic
division of the nuclei or cytoplasmic centers (coenocentra) in the
zoosporangia.

HUMPHREY (’92) first studied oogenesis in Saprolegnia by means
of modern technique, but was soon followed by Trow (’95, ’99) and
Hartoec (95, 96, 99). There seems to be a great diversity of opin-
ion as to the behavior of the nuclei, which far exceed the ultimate
number used in the formation of eggs. Humpurey and Harroc
believe that the nuclei fuse in groups to form the functional nuclei.
Trow claims that many nuclei degenerate until the requisite number
is reached, which results Davis (:03) has confirmed, but differs
from TRow in regard to the sexuality of the Saprolegniaceae. The
oogonium arises as an enlargement of the end of a hypha, into which
passes a dense mass of cytoplasm and nuclei. A central vacuole is
formed, with a peripheral layer of protoplasm lining the walls in
which lie the nuclei. The nuclei divide once by mitosis. ‘The proto-
plasm aggregates into masses which form the eggs. The process of
separating these masses by means of a series of fusing vacuoles, has
been described by Davis. He finds that the egg initials are formed
about cytoplasmic centers (coenocentra), much as has been described

1906] OVERTON—THECOTHEUS PELLETIERI 479

for certain Peronosporaceae. It seems apparent that, even if we
accept FAuLt’s description of spore formation in the ascus, the data
are quite insufficient to support any view which homologizes the ascus
with the zoosporangium or oosporangium of the Oomycetes.

BARKER (:04) announces that the protoplasm in the developing
ascus of Ryparobius shows a series of changes in spore formation,
which appear to be intermediate between typical methods in spor-
angia and asci. The account is only preliminary and has been referred
to above. My own studies on the asci of Thecotheus however, have
shown the process of spore formation to be as in other typical asci,
namely, by means of the kinoplasmic radiations of the nucleus.
Although more than eight spores are formed in the ascus, the process of
spore delimitation is that found in a typical ascus. There is abso-
- lutely no evidence that the process is in the least similar to spore
formation as found in the sporangia of the Oomycetes or in those of
the Phycomycetes. The results obtained do not seem to throw the
least light on the homology or origin of this peculiar organ. It
apparently makes no difference whether less than eight spores are
formed or more than eight, the phenomena of spore delimitation are
exactly the same as found in typical eight-spored asci.

That a true alternation of generations, comparable to that found
in the higher plants, exists among the Ascomycetes, is certainly obvious
from the fact that the asci eventually arise as the result of fertilization.
DEBary (70) advanced the opinion that the ascus fruit represents
an asexual generation, and WoRoNIN (’70) compared it to the spor-
ogonium of the moss, which idea was farther emphasized by HARPER
('96) for Erysiphe. The only essential difference is that the egg is
never separated from the parental tissue system, agreeing in this
Tespect with that of the red algae. HARPER also pointed out that
the ascus is an analogue of the spore mother cell of the higher plants,
and that the triple division corresponds to the double division in the
Spore mother cells of the higher plants, with a probable consequent
chromosome reduction in the ascus. This view is further supported
by the recent discoveries of MAIRE (:05), Harper (:05), and GuiL-
LIERMOND (:05) on the nuclear phenomena in the ascus, by which
Teduction of the number of chromosomes and a consequent return
to the gametophyte generally occur. These authors have found

480 BOTANICAL GAZETTE [DECEMBER

that the first division of the ascus nucleus is preceded by a well-
marked synapsis phase, which the most recent zoological and botanical
investigations have shown to be the most characteristic and impor-
tant phase of the heterotypical division. While Marre finds a synap-
sis similar to that described by STRASBURGER (:04), HARPER and
GUILLIERMOND have found the phenomena to be essentially the same
as in the pollen mother cells of the flowering plants studied by GrE-
GOIRE (:04), BERGHS (:04, :05), ALLEN (:04, :05), ROSENBERG
(:05), STRASBURGER (:05), Mryakr (:05), OVERTON (:05), TISCH-
LER, (:06), and Carprrr (:06). Harper finds’ permanent central
bodies in the nuclei of Phyllactinia, and that the chromosomes are
permanently attached to the central body and are thus brought
side by side in nuclear fusion. On this ground he concludes that the
chromosomes are permanent structures, and that they must be bivalent
in the nuclei of the young ascus, due to the earlier fusion of the sexual
nuclei. These bivalent chromosomes, he holds, further unite in syn-
apsis to form quadrivalent structures, consisting of four somatic
chromosomes arranged side by side, thus accounting for a numerical
reduction just as in the higher plants. Marre says that the first
division of the ascus nucleus is heterotypical, while the second is
homeotypical, which opinion GuILLIERMOND also holds. HARPER
gives no opinion as to which are the reduction divisions. He has
pointed out, however, the universality of the occurrence of the double
division, following synapsis in the spore mother cells of all higher
plants, as necessary to accomplish chromosome reduction, where the
chromosomes are bivalent structures. I might also call attention in
this connection to the elimination of the double division in embryo sac
mother cells of parthenogenetic angiosperms, discovered by JUEL (:00,
705), MuRBECK (:01), OvERTON (:04), and STRASBURGER (:05),
where reduction is not completed.

HarPeER also points out that the universal triple division occurring
in the ascus, no matter how many spores are to be formed, is probably
to be associated with a quadrivalent character of the chromosomes
in the ascus nucleus. Where one nuclear fusion occurs, as in most
plants and animals, a double division is necessary to complete the
reduction and to distribtite the elements to the daughter nuclei;
while when two nuclear fusions occur, as in Ascomycetes, a triple

Be ae ee OTE Nd te SO Ege ROE, Pee ee

Ce keane te Oe ee ort Pan Pe A eS ae

sa far ytd Eo

1906] OVERTON—THECOTHEUS PELLETIERI 481

division and a double reduction is necessary to accomplish the same
results. This triple division of the ascus nucleus occurs universally,
whether two spores, four spores, or eight spores are to be formed.
HARPER has pointed out how fundamental this triple division is, since
when only two spores are to be formed, as in Phyllactinia, six nuclei
degenerate. In such cases the three divisions constitute a single con-
tinuous process. That all these divisions persist, no matter how many
spores are to be produced, shows their necessity in the process of
reduction.

The work of BLrackMAN (:04) and his students (:06) and of
CHRISTMAN (:05) have established an undoubted alternation of
generations in the rusts, showing that in these forms the series of
binucleate cells originate as a result of fertilization. The gamete
nuclei persist throughout the sporophyte generation as independent
nuclei, dividing by a conjugate division. In the teleutospore these
nuclei fuse, and a synapsis stage occurs, followed by a double division
which leads to the formation of the four nuclei of the four sporidia.
As Harper suggests, there is a striking parallelism between the teleu-
tospore and the spore mother cell of the higher plants. He believes
we are justified in regarding the first and second divisions in the
promycelium as respectively heterotypical and homeotypical. As
there is only one nuclear fusion in the life cycle of the rust, a conse-
quent double division occurs in reduction. Marre (:05), finding
in Galactinia that certain of the cells of the ascogenous hyphae which
give rise to the asci are binucleate, holds to the conception that these
binucleate cells correspond to those of the Basidiomycetes as well as
to those of the rusts. There should be a series of binucleate cells in
the sporophyte in all these groups, whose nuclei should divide by
conjugate division, fusion first taking place in the basidium, in the
teleutospore, and in the ascus, each of which would be comparable
to the spore mother cells of the higher plants. This explanation
does not explain, however, the universal occurrence of the third divi-
sion, which is so general among the Ascomycetes, and which FauLt
has found to occur in the Laboulbeniaceae; nor does it account for
the apparently secondary nature of the fusions described by BLAcK-
MAN and CHRISTMAN, as compared to those of the red algae, lichens,
mildews, and Pyronema. It is certainly of great importance to know

482 BOTANICAL GAZETTE [DECEMBER

how the ascocarps of Galactinia, Acetabulum, and Pustularia arise,
and whether apogamy or parthenogenesis is associated with the appear-
ance of binucleate cells in the ascogenous hyphae.

The cells of the ascogenous hyphae of Thecotheus are not binu-
cleate, and I am inclined to accept for this form HARPER’s interpre-
tation that the asci are spore mother cells, modified by adaptation
as explosive organs and as reservoirs of reserve food supply, in which
a merely vegetative fusion has occurred to maintain a definite nucleo-
cytoplasmic relationship. A triple division follows to complete the
reduction and distribution of the somatic chromosomes to each of
the resulting eight nuclei. The sporophyte would thus include the
ascogenous hyphae and the asci up to the time of the reduction
division, which initiates the gametophyte generation.

In the typical ascus the nuclei of the eight spores contain the gam-
etophyte number of chromosomes, as would. also be true when only
two or four spores are formed. When any of these spores germinate,
they give rise to true gametophyte structures, usually a septate
mycelium, which may reproduce itself asexually by conidia before
sexual reproduction, as in Eurotium or Erysiphe. It is well known
that many ascospores contain more than one nucleus, and, as FAULL
and others have shown, these nuclei are formed by mitotic division
of the primary spore nucleus. The spore may be septate or non-
septate. The typical ascospore is uninucleate and non-septate.
Both the number of nuclei and the number of septa in a spore vary
from one to many. Spores which are septate have apparently begun
an intrasporal germination, the gametophyte forming considerable
embryonic tissue within the old spore wall. Spores which are not
septate but multinucleate have also undergone embryonic develop-
ment, but without cell division.

We perhaps should expect from what we know of other Ascomy-
cetes that in many-spored asci, as in Thecotheus and Ryparobius,
spores would be delimited as soon as eight free nuclei were formed.
This does not occur in either of these forms, but further nuclear divi-
sions take place before the spores are delimited. A closer analysis,
however, shows that we have analogies for these conditions in the
behavior of other undoubted spore mother cells. Intrasporal germ-
ination may be looked upon as comparable to that which occurs in the

1906] OVERTON—THECOTHEUS PELLETIERI 483

spores of many of the pteridophytes and spermatophytes. The spore

not only begins its germination while inside the sporangium, but while

‘it is still iaside the mother cell. The ascus is not only to be looked

upon as a mother cell, but also as a mother cell which functions
directly asa sporangium. The prevalent impression is that the history
of the gametophyte begins with the division of the mother cell and
ends in the act of fertilization. The ordinary product of the division
of the spore mother cell is four spores, or in typical Ascomycetes
eight spores. In Lilium the first mitosis of the mother cell is hetero-
typical, while the second corresponds exactly in all details to the
second division where normal tetrads are to be formed. We have
here a double division completed inside the mother cell, and con-
sequent germination to form a gametophyte inside the mother cell.
It does not seem inconsistent, therefore, to think of a mother cell
containing a gametophyte, or that the reduction divisions may not
give rise directly to morphological spores. These nuclei are game-
tophytic in character and can give rise to gametophyte structures in
the embryo sac. It is not absolutely essential, therefore, that the double
division result in spore formation. JuEL (:00) found that in Carex
acuta the usual double division occurs in pollen mother cells, com-
plete cell plates being formed which are later resorbed, so that four
nuclei lie iaside the wall of the mother cell, three of which disin-
tegrate, the fourth forming a single functional microspore. In Fuchsia
(WILLE ’86) as many as fourteen microspores have been reported
from a single mother cell, while more or less than four have been
found in several other forms. STRASBURGER and JvuEL have also
counted numerous microspores formed from a single mother cell.
It would appear, therefore, that the double division is necessary,
but that the number of spores ultimately formed is very variable. If
in Fuchsia the walls of the microspores were eliminated, a striking

s resemblance to the sixteen-nucleate stage of Thecotheus would result.

The number of spores formed and the time of their formation seems
to be very variable, but this does not interfere with our conception of
the alternation of generations in the flowering plants. That thirty-two
free nuclei are formed in Thecotheus before spore delimitation occurs
is therefore no more striking than that tetrads are not formed as a
result of the double division in Lilium, or that more than four micro-

484 BOTANICAL GAZETTE [DECEMBER

spores are formed in certain angiosperms. It may well be sie all
the conditions mentioned represent mere adaptations.

In the lichens many-celled spores occur, which are at first always
uninucleate; for example, those of Endocarpon. The embryo gameto-
phyte is formed in the spore, which continues its growth when condi-
tions become favorable. Each cell, however, of the multinucleate
septate spore gives rise to a filament when the spore germinates.
Each cell of a septate spore is comparable to a spore of Thecotheus,
in which walls have not been formed until the nuclear divisions
have been completed. Germination occurs in the one case before
spore delimitation, and in the other case after spore delimitation.
In either case, after eight nuclei are formed we are dealing with
gametophyte structures. It is a matter of indifference when germina-
tion occurs, or when spore delimitation takes place, so long as the
triple division has occurred. The time of spore formation is a matter
of adaptation to conditions, but the essential nature of the process seems
to be the same in all genuine members of the group of Ascomycetes
so far studied.

SUMMARY.

1. The fruit body of Thecotheus is formed from several ascogonia
and is therefore a compound apothecium.

2. The ascogenous hyphae arise from any or all of the cells of the
ascogonium, and consequently the cells of the ascogonium are not
connected by perforations through which the nuclei pass to enter the
ascogenous hyphae.

3. The ascogenous hyphae do not in this case constitute a synkaryo-
phytic system.

4. The asci arise from the subterminal cells of the recurved tips
of the ascogenous hyphae, which cells are binucleate.

5. The ascus nucleus is formed by the fusion of these two primary
ascus nuclei.

6. The ascus nucleus divides by triple division to form eight free
nuclei, each of which after a period of rest and growth undergoes
further division until thirty-two free nuclei are formed in the ascus.

7. Spore delimitation follows the process described by HARPER.

8. Each spore is uninucleate from the start, no nuclear divisions
or septa being formed.

RCL een ty hee, ee ee

ee rie i

1906] _OVERTON—THECOTHEUS PELLETIERI 485

9. The exospore is laid down not from the epiplasm but by deposi-
tion from the outer layer of the sporeplasm.

to. No evidence has been found to support the theory that the
ascus is homologous with the sporangia of either the Oomycetes or
the Phycomycetes.

11. The formation of the large number of spores is evidently an
adaptive phenomenon, and does not interfere with the conception that
the ascus is a spore mother cell.

UNIVERSITY OF WISCONSIN,
Madison, Wis.

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1906] OVERTON THECOTHEUS PELLETIERI 487

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?

ic hildune im Ascus
f Oo

488 BOTANICAL GAZETTE [DECEMBER

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1906] OVERTON—THECOTHEUS PELLETIERI 489

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Te Ses EN Te ee Se NO St nh Oey Oe ae, weet ee eee wea

1906] OVERTON—THECOTHEUS PELLETIERI 491

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EXPLANATION OF PLATES XXIX AND XXX.

All drawings were made with the aid of a Bausch and Lomb camera lucida,
together with a Bausch and Lomb 7s oil-immersion lens. Plate XXX has bee
reduced one-third in reproduction.
PLATE XXIX.
IG. 1. Section of young ascocarp showing portions of ascogonia, whose

cells are already multinucleate.

Fic. 2. Median section of an older ascocarp showing ascogonia, young asco-
genous hyphae, and paraphyses.

Fic. : Median vertical section showing structure of a nearly mature ascocarp.

Fic. 4. Section showing young ascogenous hypha; the terminal cell is uninu-
cleate a the sub-terminal cell, which is to form the — is binucleate.

Fic. 5. Young ascus showing fusion nucleus with two n

Fic. 6. Portion of an ascus at time of spore ‘biiaron sowie nuclear
beak with a system of astral rays; a young spore is also shown, whose plasma
membrane is completed.

PLATE XXX,
Fic. 7. Young ascus showing primary fusion nucleus with one nucleolus.
1G. 8. Ascus with two nuclei. :
Fic. 9. Ascus with four nuclei.
Fic. ro. Ascus with eight nuclei.

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PLATE XXX

12b 12a
OVERTON on THECOTHEUS

CURRENT. LITERATURE.

BOOK REVIEWS.
The Vienna Congress.

HE PROCEEDINGS of the Congress of 1905 have recently appeared from
the press of FiscHer (Jena), apparently published by the Local Committee.*
At the same time there is published from the same house a volume containing the
“scientific results’? of the Congress as Publications scientifiques de Association
internationale des botanistes.2 The volumes have been distributed gratuitously to

members of the Congress, and are presumably for sale by the publisher; but
the price is not stated.

The volume of Verhandlungen contains an account of the organization of
the Congress and its daily proceedings in general sessions; the various excursions
before and after the meetings; the botanical ner (illustrated); but the
greater part of the space (182 out of 262 pages) is devoted to an account of the
meetings of the section for the revision of the laws of nomenclature. Here o
finds not merely the procés verbal, but a list of the delegates and the institutions
represented, an account of the discussions based on stenographic and other
notes, and the votes on each question. Then follows, with double pagination,
evidently for separate publication: (1) a concordance of the adopted rules with
the Paris Code; (2) the revised code for the vascular plants, printed in French,

the strict rule of priority; and (4) a thorough analytical index. This section of
the report shows the painstaking care of M. JoHN Brique, the gener al secretary,
to whose devotion, skill, and knowledge so much of the success of the nomen-
clature commission was due.

t Verhandlungen des eee botanischen Kongresses in Wien 1905.
nique & Vienne (Autriche) 1905. Heraus-
co) Ss von VON

a
re)

4 Werrsrern und J. Wiesner als Priasidenten un
_ Sekretiir. — von J. Briquet (Genf), A. GINZBERGER, V. SCHIFF
v. Wenyzret, R. v. WeErTsTEIN und A. ZAHLBRUCKNER (Wein). Imp. pond pp.
vi+ 262. i 7. Jena: G. Fischer. 1906.

. Publications scientifiques de l’Association internationale des botanistes.

von WETTSTEIN und J. WresNer als Prisidenten und
_ Sekretir. Redigiert von P. J. Lorsy, General-Sekretar des Ass. Int. des Bot. Imp.
-8vo. pp. vit 446. pls. 3. map 1. figs. 58. Jena : G. Fischer. 1906.
493

494 BOTANICAL GAZETTE [DECEMBER

It seems a bit invidious to distinguish the other volume as Résultats scien-
lifiques; but it may pass as a conventional title. The four hundred odd pages
are occupied by the formal addresses, and papers volunteered for the Congress,
twenty-six in number. They are therefore of unequal quality and of different
character. Some are general summaries of the present status of important
divisions of botanical science; others are special and technical. Only one comes

tom America—‘‘A classification of Uredineae based on structure and develop-
ment,” by Dr. J. C. ARTHUR—and this is translated into German. The only
English pages are those of Dr. D. H. Scort on “The fern-like seed-plants of the
carboniferous flora.” A good index makes available the entire contents. The
two volumes should be in every botanical reference library.—C. R. B

Knuth’s Handbook.

In 1899 the first volume of KNutH’s Handhuch der Bliitentologie appeared,3
based on HERMANN MUILER’s Die Bejfruchtung der Blumen durch Insekten.
It is general and deals with the structure of flowers and of insects in relation
to pollination. In the same year the second volume appeared,+ giving an account
of all known observations upon the pollination of the flowers of arctic and tem-

other than Europe. The Clarendon Press has undertaken the publication
of an English translation, the first volume of which has lately appeared,5 and the
second volume is announced as being in press. The translator is J. R. Atns-
worTH Davis, Trinity College, Cambridge, and the prefatory note is by Pro-
fessor I. B. BaLrour.

The character of this encyclopedic work is well known to students of pollina-
tion, and it is a great boon to English and American botanists to possess it in
an English translation. The original text appeared ‘in instalments, and the
appendices of supplementary information have been incorporated in :he body
of the text by the translator. A special feature of the translation is the bringing
together in one list all the citations in the original, and completing the record
to January 1, 1g04. The number of citations is almost beyond belief, the botan-
ical titles in the bibliographical list reaching 3748. It must be said, however,
that the citations are probably more numcrous than significant, as a cursory
examination suggests. There are frequent cases where “fertilization” is con-
fused with “pollination,” and papers cited which can hardly be imagined as
belonging to the real literature of pollination. Then too, there is occasional
duplication of titles, as for example titles 633 and 643, which are identical in
every particular. The dreadful task of editing such a mass of citations should

3 Bor. GAZETTE 28:280. 1899.

4 Bor. GAZETTE 28:432. 1899.

‘Knutu, Paut, Handbook of flower pollination. Translated by J. R. AINS-
wortH Davis. Volume I. 8 vo. pp. xix+382. Oxford: Clarendon Press. 1906.

1906] CURRENT LITERATURE 495

excuse many slips, but the serious question is as to the value of such a mass of
undigested citations.

n any event, the translation is exceedingly welcome, and should go far
toward stimulating a study to which American botanists pay scant attention.

A New Zealand Manual.

In 1864 Sir JosepH D. Hooker published the first part of his Handbook
of the New Zealand Flora, which belonged to a uniform series of floras contem-
plated for all the British colonies. In 1894 the late Mr. T. Krrx was engaged
by the New Zealand government to prepare a Student’s Flora of New Zealand,
but at his death in 1897 barely two-fifths of this task had been completed. This
fragment has since been published by the government, but the need for a com-
plete and convenient flora was becoming so acute that in 1900 Mr. T. F. CHEESE-
MAN, curator of the Auckland museum, was appointed by the government to
prepare a Manual of the New Zealand Flora, and this has now appeared.°

The instructions to the author included one to follow the general plan of
-Hooxer’s Handbook, and another to include only indigenous plants. However,
in an appendix the New Zealand families are arranged in the Engler and Prantl
sequence; a list of the naturalized plants is also given, and a very long one it is.
There is also an alphabetical list of Maori names of plants, and a full glossary.
A most interesting and valuable contribution, contained among the introductory
pages, is ‘“‘A history of botanical discovery in New Zealand,” from Cook’s first
visit in 1769 to the present year.

As is customary, only the vascular plants are included, and the range covered
includes not only the two main islands of the Colony of New Zealand, but also
the outlying groups of the Kermadec Islands, the Chatham Islands, the Auckland
and Campbell Islands, Antipodes Island, etc. Macquarie Island is also included,
although it belongs to Tasmania, because it is more closely allied in its flora
to the Auckland and Campbell Islands than to any other land. The descriptions
are in almost all cases original, and have been based upon the examination of
living or dried material, extending through thirty-five years of continuous study
and collection of the flora. Surely no one of larger experience could have been
selected to do this work, which gives evidence throughout of most painstaking

The four largest families, with species numbering from 221 down to 113, are
Compositae, Cyperaceae, Scrophulariaceae, and Gramineae;
positae constitute one-seventh of the whole flora. The largest genus 1s Veronica,

6 CHEESEMAN, T. F., Manual of the New Zealand Flora. 8vo. pp. xxxvi+ I199.
Wellington: Published under the authority of the Government of New Zealand.
1906.

496 BOTANICAL GAZETTE [DECEMBER

with 84 species, followed by Carex, Celmisia (Compositae), Coprosma (Rubi-
aceae), Ranunculus, Olearia (Compositae), etc. Numerous new species are
described and a new genus (Townsonia) of Orchidaceae is established. The
most remarkable fact is that of the 1571 species 1143 are endemic, nearly three-
fourths of the entire flora. Of the 428 species found elsewhere, 366 extend to
Australia, and 108 to South America. This almost complete “‘strangeness’’
of the flora to botanists who are familiar with the north temperate floras and
who have even visited the tropics, gives it a fascination suggestive of just as
strange results if such material could be made available in their laboratories.—
MC

MINOR NOTICES.

Development of fern leaves.—MArcarer Stossow has brought together in
an elaborate book a remarkable series of observations upon the development
of fern leaves.? She has selected nineteen representative species from north-
eastern United States, and illustrated them by forty-six handsome plates repro-
duced from photographs. . A preliminary chapter contains a general description
of the development of form and venation, often showing remarkable changes
in passing from the juvenile to the mature form. In the subsequent chapters
each species is first described in its mature form, and then follows a very detailed
description of the transition forms from the juvenile stage. The possible range
of leaf variation is also considered. The book contains a mass of suggestive
observations, which should serve as a check to any characterization of species
from insufficient material, and as a demonstration that the numerous “form
species” of fossil “ferns” are more than doubtful. The book is more of a contri-
bution than its elaborate form would suggest.—J. M. C

Portraits of botanists.—D6rr.er, editor of Botaniker-Adressbuch, has issued
the first two parts of a proposed series of portraits of botanists. Each part
contains ten portraits, g9X12.5°", which are phototype reproductions upon
fine art cards, each card also bearing the signature of the botanist in fac-
simile. The cards are loose, being ready to frame and worthy of it. It is announced
that 100 portraits, with title page and index, will form a volume. A grape of
text accompanies each portrait, giving the most important biographical data
and bibliography. Each part ao 5 marks to subscribers; single portraits
can be obtained for 1 mark; and 10 selected portraits for 8 marks. The first
part contains portraits of Kkewen, Wiesner. WARMING, ENGLER, DEVRIES,
Guicnarn, Scurérer, Martrroto, Witte, and WettsTEIN; = second
part, Frres, (Elias and Theodor), Prerrer, Boropin, HACKEL, SCOTT,
GOEBEL, ERRERA, CHopat, and keno, The address is J. DORFLER, aoe
36, Wien, ITI.—J. M. C.

7 SLosson, Marcaret, How ferns grow. 8vo. viiit+156. New York: Henry
Holt & Cauniy. 1906.

1906] CURRENT LITERATURE 497

Ustilaginales of the North American Flora.—Another part of the North
American Flora has appeared, containing the Ustilaginales by Ctinron.2 The
changes from a former monograph? by the same author are mostly such as adapt
the monograph to the style of the Flora. The older European synonomy, the
list of species showing general distribution, and the extensive bibliography of the
former publication are omitte he omission of the general notes relating to
the genera and species is a dint nct disadvantage. It takes away from the des-

its description far more readily than do the technical dia s. The host
index in its present alphabetical arrangement of hosts, with se references to
the parasites, represents a marked improvement over the former arrangement.

Artificial keys for the determination of species have been added eee: the genera.
—H. HAsseprinc.

Index Filicum.—This work is completed by the twelfth fascicle'®, which
concludes the catalogue of literature, and also includes a systematic enumeration
of the genera. It appears that 23,499 names are cited, but that only 149 generic
mames and 5940 specific names stand. It is interesting to note that these species

h

Ophioglossaceae 78. This sequence of families is that used
by the author. The parts have appeared with most commendable promptness,
and the completed volume will be a most useful one.—J. M. C

Trees of the Amazon region.—HvBER has issued the third and fourth decades
of his Arboretum Amazonicum,* the first two parts having appeared in 1900.’
The superb quality of the plates is maintained, and, as before, each plate is
accompanied by at least a page of descriptive text in Spanish and French in
parallel columns. There are habit studies of different palms, legumes, etc.,
views of different types of savannas, characteristic river-bank vegetation, forest
interiors, effect of wind on trees, etc. These glimpses of tropical plants and
plant formations are among the very finest that have been published.—J. M. C

8 Ciinton, G. P., Ustilaginales. North American Flora 7: part 1. pp. 82.

October 4, 1906.
orth American Ustilaginaeae. Proc. Boston Soc. Nat. Hist. 31:329-529.

1904. Reviewed in Bor. GAZETTE 39:314- 1905.

to CHRISTENSEN, C., Index Filicum, etc., Fasc. 12. Copenhagen.: H. Hagerup.
1906, 35. 6d.

tt HuBER, J., Arboretum Amazonicum. oe desplantes Soe gn et
cultivées les plus importantes de la région Amazonienne. Decades 3 and 4. 4to.
Para. 1906. Each decade ro fr.

™2 Bor. GAZETTE 33:72. 1902.

498 BOTANICAL GAZETTE [DECEMBER

a

Ptelea.—A revision of this genus as it occurs in western and southwestern
United States and Mexico has heen published by Grrenr."3 Under his treat-
ment the genus has become rich in species, 59 being recognized, of which 55
are new. Three natural groups are defined, each with its own geographical
range: (1) species (37) with chestnut-brown twigs and prevailingly glaucescent
or bluish-green foliage; (2) species (13) with amost white twigs and yellow
green foliage; (3) species (g) with cinnamon-colored twigs, a peculiar hue and
venation of foliage, and narrow-winged or even wingless samaras.—J. M. C.

Anatomy of Commelinaceae.—Hotim has published an elaborate memoir"4
dealing chiefly with the general morphology and anatomy of the Commelinaceae.

€ 17 species investigated represent the genera Commelina (5), Aneilema,
Tinantia, Tradescantia (9), and Weldenia. The memoir is a mine of informa-
tion which can be drawn upon by the future student of the group who is seeking
to organize such details into general statements.—J. M. C.

Genera Siphonogamarum.—The eighth fascicle of Datta Torre and
Harms’s'S list of the genera of seed plants concludes the genera of Compositae,
9629, Thamnoseris being the last one. The genera of uncertain affinity swell
the number of genera to 9810. There is also a supplement of 51 pages, and
the general index of names is begun.—J. M. C.

NOTES FOR STUDENTS.

Ancient Araucarians.—In Jurassic and Cretaceous deposits there occur
abundant remains of leafy branches of coniferous plants that have been described
under the generic name Brachyphyllum. The genus has been referred by various
authors to Araucarineae, to Cupressineae, and to Taxodineae (near Sequoia) ;
but in a recent paper by Jerrrey and Hotticx"® it is shown from an investi-
gation of the internal structure that here can be no doubt as to its Araucarian
affinities. In the same paper Protodammara is described as a new genus, to
include certain Cretaceous cone scales that had been referred to the living genus
Agathis (Dammara). Certain lignites associated with both Brachyphyllum
and Protodammara were also found to be Araucarian; and the conclusion is
reached that these lignites represent the wood of the trees which bore the leafy

ENE, EDwarD L., The genus Ptelea in the western and southwestern
United Stated and Mexico. Contrib. U. S. Nat. Herb. 10:49-79. 1906.

14 Hotm, THEODORE, Commelinaceae. Morphological and anatomical studies of
the vegetative organs of some North and Central American species. Memoirs Nat.
Acad Sci. 10:159-192. pls. 1-8. 1906
- Datta Torre, C. G. DE and Harms, H., Genera Siphonogamarum ad systema
Englerianum conscripta. Fasc. 8. pp. 561-640. Leipzig: Wilhelm Engelmann.
1906. M6. :

+6 HOLLick, A., and JeFrrey, E. C., Affinities of certain Cretaceous plant remains
commonly referred to the genera Dammara and Brachyphyllum. Amer. Nat. 40:
189-215. pls. I-5. 1906.

_~ 1906] CURRENT LITERATURE 499

branches called Brachyphyllum and the cones called Protodammara. Th
multinomial genus was thought by the authors to be “‘in all probability the last
survivor of an ancient Araucarian line of descent, joined near its base with the
primitive stocks of the Abietineous and Cupressineous series

More recently JEFFREY has been able to study the wound mites of Brachy-
_ phyllum and to draw from them more definite conclusions as to its relationships.*7
In a well-preserved specimen of the wood, Brachyphyllum can be distinguished
at once from any living Araucarian by the absence of resiniferous elements other
than those found in the pith-rays. In this feature the genus resembles such old
gymnosperm groups as the Pteridospermae, Cordaitales, and Cycadales, and
also the very ancient but still flourishing genus Pinus. Jerrrey further finds
that Brachyphyllum agrees with the Abietineae in its traumatic reactions, resin-
canals being formed as a result of wounding. Following the line of reasoning
used in connection with his work on Sequoia,'® he concludes that these reactions
furnish one evidence that the Araucarieae are phylogenetically connected with
the Abietineae; and that Agathis and Araucaria hold the same relation to Brachy-
phyllum that the other genera of the Cupressineae hold to Sequoia. This phy-

position of existing Araucarians among existing Coniferales, and also on account
of Sewarp’s recently expressed views’? in reference to the relationships and
origin of the Araucarians.—J. M. C.

Adsorption of chlorophyll.—It has always been troublesome to explain the
differential extraction of the chlorophyll pigments by their solvents under various
conditions, and Tswetrt seeks to supply a better theory.?° Thus, fresh leaves or
those ground in a mortar with sand or emery and covered with petrolether yield a
more or less pure-yellow extract of carotin, with traces of other pigments. ried
leaves, even at a lower temperature, yield even purer carotin. But boiled leaves,
_ or even warmed tissues, yield green extract. Alcohols (methyl, ethyl, and amyl),
acetone, acetaldehyde, ether, and chloroform give a green extract with fresh,
dry, or boiled leaves, dissolving all pigments freely. It suffices to add a little
alcohol (10 per cent. for fresh, 1 per cent. for dry leaves) or the other solvents to
petrolether to secure a beautiful green extract. How explain these facts ?

If strips of filter paper be put into a flask with an alcohol- petrolether solution
and the solvent evaporated in vacuo, the pigments become concentrated in the
paper. This dry green paper now behaves toward solvents exactly as above
stated for the green leaves. This, Tswertr holds, indicates that the pigments?s

17 JEFFREY, E. C., The wound reactions of Brachyphyllum. Annals of Botany
20: 383-304. pls. 27-28. 1906,

18 See Bot. GAZETTE 38: 321. 1904.

19 See Bot. GAZETTE 42:224. 1906.

20 Tswett, M., Physikalisch-chemische Studien iiber das Chlorophyll. Die

Adsorptionen. Ve ack Bot. Gesells. 24:316-23- 1906.

500 BOTANICAL GAZETTE [DECEMBER

are absorbed by the stroma, i. e., held mechanically by molecular affinity, and

in different degrees under different conditions, this molecular attraction being

overcome by the various solvents unequally. Consequently, it is argued, the

pigments cannot exist as grana in the stroma—a conclusion already indicated

by recent study both with microscope and ultramicroscope. Many bodies

beside cellulose hold the pigments in like fashion. The work is suggestive, but
SWETT’s crucial experiment is not convincing.

Inasmuch as the different pigments are held fast unequally, if a petrolether
solution, or even better a solution in carbon bisulfid, be filtered through a column
of calcium carbonate, the pigments are distributed in zones, the more firml
adsorbed ones above, the less firmly fixed successively lower. Such a preparation
he calls a chromatogram, and the method the chromatographic method.?"

In a later paper?? Tswett gives further details of the technique and analyzes
the zones of his chromatogram. The synonymy of the chlorophyll pigments is
so tangled that it is almost impossible to compare the work of different investi-
gators. The chromatographic method promises to be of use in demonstrating
that there are different pigments, but its value in research seems questionable.
—C.R.B

The Svalof Experiment Station.—Although the work of the Swedish Agri-
cultural Experiment Station at Svaléf is widely celebrated because of its note-
worthy economic results, these results and the means by which they have been
attained are not generally understood, owing to the fact that all of its reports are
printed in the Swedish language. Dr Vrres has devoted two recent papers?3 to a
discussion of the Svaléf methods and their scientific significance. In the first
of these papers is given a brief history of the station, together with an exposition
of the methods employed. The history of the station falls rather naturally
into four 5-year periods, each marked by a characteristic advance. During

e first period, 1886-1891, the work of introduction and testing of varieties, in
the way usually done by Agricultural Experiment Stations, presents nothing
unique, the several sorts being treated as units. With the appointment of Dr.
H. Nitsson as Director in 1890 begins the second period, in which the discovery
was made that each variety is a mixture of a large number of elementary forms
and that the latter are the real units with which scientific agriculture must deal.
In the third period was carried out the great work of segregating the elementary

st bt kdaed Propores to call the collective green pigment of leaves chlorophyll;

green fl ; the yellows already are distinguished
sefearotins a xanthophylls.

22 Tswett, M., Adsorptionsanalyse und chromatographische Methode. Anwen-
oS idie Chemie des Chlorophylls. Ber. Deutsch. Bot. Gesells. 24: 384-393-

23 ne a Hueco, Die Svaléfer Methode zur Veredelung landwirthschaftlicher
Kulturgewachse und ihre Bedeu _, fiir die Selektionstheorie. Arch. fiir Rass. u.
Gesells. tone 3:325-358. My-Je 190

re und neu capa Meine Biol. Centralbl. 26: 385-395. Jy 1906.

1906] CURRENT LITERATURE 501

forms, studying their morphological characters, and testing their relative value
by parallel cultures. During the last five years the successive generations of
these segregated pure races have been followed, with the result that a considerable
number of mutants have been found and tested. In both papers DeVries
compares NILsson’s pedigree-culture method with the older and still almost
universal method of selection in which the undesirable individuals are destroyed
and all the best are saved and sown together. He concludes that Rrimpavu could
have produced the Schlanstedt barley, for which he is so widely celebrated, in
four or five years by the Svaléf method, instead of having to devote to it the.
20-25 years required by the older method. The magnitude and quickness of the
results at Svaléf, where alone the conception of constant elementary forms has
been adopted as the basic principle, indicates the importance of the newer con-
ceptions of evolution for scientific agriculture, and these papers of DEVRIEs
bring to the notice of the non-Swedish world methods which will doubtless lead
to most important changes in the conduct of the various agricultural stations.—
_ Gero. H. SHULL

Report to Evolution Committee.—In a third report to the Evolution
mittee of the Royal Society, BATESON, SAUNDERS, and PUNNETT?4 have s
that practically all the complexities encountered in their study of hybrid sock
sweet peas, and poultry are in essential accord with Mendelian expectation if
the assumption is made that what appears externally as a single character may
_be in reality dependent for its appearance upon the presence of two or more
independent allelomorphs or internal units. In some cases the nature of these
internal units is apparent, as when the presence of one always changes a pigment _
from red to blue; but in other cases there is no clue to the nature of the indi-
| aan allelomorph, as when the combination of two white sweet peas sesaeed

ce colored offspring owing to the bringing together of two allelomorphs

Pinbined action of which is necessary to the production of color. In stocks ru

sats

of America (December 1905) the reviewer presented a paper on the “Latent
characters of a white bean,” in which it was shown that the color of purple
mottled beans obtained as an F, from a cross between yellow and white is depend-
ent upon the simultaneous presence of three distinct allelomorphs. In that
: pepe ity was ie predicted _— oo Ss ——* on — and sweet peas would
e assumption of com-
lex and inexplicable synth d resolution of "hypallomors as attempted
in the earlier Reports to the Evolution Committee. The completeness with
which the new point of view is demonstrated by these fecha | ath ah will ©
do much to strengthen the view that Mendelian behavior is a more common
” 24 BaTESON,W., SAUNDERS, Miss E. R., PuNnerr, R. C, ay epost to the Evolu-
tion Committee. III., pp. 52. London: Harrison & Sons. 1

502 BOTANICAL GAZETTE [DECEMBER

phenomenon than previous observations would have indicated. | Although stocks
behave in a rather simple way when the analysis given by the authors is compre-
hended, the recombination of the allelomorphs that have been discovered in this
plant yields in the second generation 243 distinct types, and it is plain that in
still more complex cases a perfectly typical Mendelian behavior would easily
exceed the keenest human power of analysis to unravel.—Gro. H. SHULL.

Sterilized soil —Scuu1ze finds?s that plants grown in sterilized soil are affected
by two opposing factors: (1) the formation of more or less injurious decom-
position products in the sterilizing process, which act upon the plants ‘“‘according
to the degree of their sensitiveness” (this phrase obviously hides ignorance of
other factors); (2) an advantageous release of nutritive materials, especially
of the otherwise unavailable nitrogen. According as one or the other of these
factors prevails the crop is increased or diminished by sterilizing the soil. But
even when the crop is diminished the N-content may be markedly increased.
By the addition of lime the injurious effect of the decomposition products may be
almost or wholly counteracted. The significance of these researches for pot-
cultures in sterilized soil is obvious, invalidating many conclusions based upon
such experiments when this factor had not been considered.—C. R. B.

Moss rhizoids.—Kurt ScHOENE finds*® that rhizoids rarely arise from the
germinating spores of any mosses except Funaria, in which they regularly appear.
Lack of nitrogen suppresses the chloronema of Funaria, reducing it much in
others; and lack of either nitrates or phosphates enormously lengthens the rhi-
zoids of Funaria. These peculiarities of spore germination mark Funaria as a
ruderal plant. The rhizoids show a gradation in their significance as organs
of food supply, diminishing from the forms with a central strand to those without
it, this function entirely disappearing in water forms. (The experiments on
which this statement rests are too few and inconclusive to be convincing.)
The oblique position of partitions is held to be a mechanical arrangment for
resisting longitudinal strains and too great deformation of plasma on bending.
It is not obvious that in nature such dangers often threaten.—C. R. B.

Items of taxonomic interest.—Oaxes Ames (Proc. Biol. Soc. Washington

Asclepiadaceae from Guatemala—C. B. CLARKE (Kew Bull. 1906:251) has
published a new African genus (Crossandrella) of Acanthaceae.—A. D. E. ELMER
(Leaflets on Philipp. Bot. 1: 42-73. 1906) has published new Philippine species
under Pandanus (2), Ficus (8), and the Rubiaceae (14).—J. M. C.

25 SCHULZE, C., Einige Beobachtungen iiber die Einwirkung der Bodensterilisa-
tion auf die Entwickelung der Pflanzen. Landw. Versuchs-Stat. 65:137-147. 1906.

26 SCHOENE, Kurt, Beitriige zur Kenntnis der Keimung der Laubmoossporen
und zur Biologie der Laubmoosrhizoiden. Flora 96: 276-321. 1906.

NEWS.

CuesTER A. Dartinc, Albion College (Mich.), has been appointed assistant
in botany at Columbia University.

Dr. ALBERT MANN, Department of Agriculture, has been appointed pro-
fessor of botany at George Washington University.

A BIOGRAPHICAL SKETCH, with portrait, of the late C. B. CLARKE is published
in Journal oj Botany for November, having been prepared by D. Prarn and W.
H. Butss

Proressor L. H. Bartey, Cornell University, was elected president of the
Association of Agricultural Experiment Stations at the recent Baton Rouge
meeting

R. A. C. SEWARD, formerly university lecturer, has been elected to the
professorship of botany at Cambridge made vacant by the death of Professor
H. MarsHatt WARD.

PROFESSOR ROLAND THAXTER, Harvard University, has returned from his
year’s leave of absence. A portion of his time was aah in South America
and included a collecting trip to the Straits of Magellan

THE DATE of publication of the November GazeTTE should have been given
as November 30 instead of November 17. After the number was printed publi-
cation was delayed by unforseen difficulties with the plates, due toa lithographer’s
strike.

IN CONNECTION with the recent quatercentenary celebrations of the Uni-
versity of Aberdeen, honorary degrees were conferred on the following botanists:
Casmutrr DECANDOLLE, Geneva; Huco DEVrirEs, Amste ; J. Martsv-
MURA, Tokyo; and D. H. Scort, Kew.

Ir 1s appropriate to call attention again to the limitations which the Editors
have been obliged to establish for papers published in the GazeTTE. No article
exceeding thirty-two pages is acceptable, except with the consent of the author to
pay for the pages in excess of thirty-two, which will be added to the usual
number

THE DEPARTMENT OF AGRICULTURE, in its Yearbook for 1905, publishes a
paper on the progress of forestry during that year. The year is regarded as “an
epoch in the history of American forestry,” chiefly because during that year it
“passed out of the stage of preparation and propaganda into that of actual work.”
On February 1, 1905, the administration of the national forest reserves came
under the Department of Agriculture, and by the end of that year an efficient
system of forest administration was being inaugurated upon a hundred million
acres of forest lands. :

593

504 BOTANICAL GAZETTE [DECEMBER

THE Royat Society of London has awarded recently the following medals
to botanists: A Royal medal to Dr. D. H. Scorr for his investigations and dis-
coveries in connection with the structure and relationship of fossil plants; the
Darwin medal to Professor Huco DEVrigs on account of the significance and
extent of his experimental investigation in heredity and variation.

THE FIRST SESSION of the next annual meeting of the American Association
will be held at Columbia University on the morning of Thursday, December 27.
During Thursday and Friday Section G will meet at Columbia University; but
on Saturday it will meet in connection with the Botanical Society of America
at the New York Botanical Garden. The meetings will continue on Monday
and Tuesday, or as long as is required by the program.

THE UNIVERSITY OF CALIFORNIA has received by donation the herbarium
and botanical library of Mr. and Mrs. T. S. BRANDEGEE, of San Diego. The
herbarium is one of the most important in the west, since it contains some-
thing over 100,000 sheets of carefully selected plants, mostly representative
of the Mexican flora, which for many years has been Mr. BRANDEGEE’S
chosen field, and of the flora of California and neighboring states, which has
received careful treatment at the hands of Mrs. BRANDEGEE. It contains the
sole remaining duplicate types of many species, the originals of which were lost
in the recent fire that destroyed so large a portion of the herbarium of the Cali-
fornia Academy of Sciences as well as the types of practically all the new species
described by Mr. and Mrs. BRANDEGEE themselves. Among the noteworthy
“sets represented are BrxB’s willows, PaARRy’s Manzanitas and Chorizanthes,
a majority of the Mexican sets distributed by PALMER, PRINGLE, LUMHOLTz,
Purpus, etc., and a selection of types and duplicate types from the ORcUTT
and CLEVELAND herbaria. It is probable that no other herbarium contains so
nearly complete a representation of the North American Borraginaceae. It is
also rich in Mimulus, Eriogonum, and other groups in which Mrs. BRANDEGEE
has been particularly interested.

The University Herbarium, as now enlarged, numbers seieiinahty 250,000
sheets, a majority of which are mounted in permanent form. The whole collec-
tion is available for study and occupies fire-proof quarters in one of the buildings
recently erected on the University campus.. Here visiting botanists desiring to
study the West American and Mexican flora or to consult the working library of
the herbarium, will be welcome and given every opportunity for research work,
Mr. and Mrs. BRANDEGEE will continue their studies at the University where

, BRANDAGEE has been appointed Honorary Curator of the Herbarium.
Mail matter may hereafter be addressed to them at the University.

GENERAL INDEX.

he most important classified entries will be found under Contributors, Personals,

fk
and Reviews.
in bold-face type; synonyms in italic.

A
Abrams, LeRoy 2 . ery 319

398
Abutilon Avicennae, delayed germina-

on 2
yen on reduction and synap-

inccuttomn lutescens 51
Acoridium 502
en ase
is 5, Cc. C. on ecological survey of N.
ich. 2 230
orption . prneabe aer 499
nmeaae
at tris, oie eames 241
Agriculture, nipgrguioa n 6
Algae, color 233; ec ology 2305 physio-
logically balanced solutions 127
Alternation of generations, Polysipho-
nia 432
Amazon ren pe trees of 497
ona Oakes 502
rican Association, N. Y. meeting
°.

Amphiestes 226
Anaerobic respiration 307
Ana —_ ee milio, on varieties of to-
bac
Anastraphia 225
Andrews, F. M., on anatomy of Epigaea

Anemone — 52; stylosa 52,
zephyra
Anthoceros, Nosise colonies 55

Anthracnoses, appressoria 135
Ratipodal cells

pogamy, in Dasylirion 231; in Hiera-

cium 315
Apple, black rot 317; scab 238; spray-

ing x

Appressoria of anthracnoses 135
Aquatic biology, problems in 230
Aquilegia vilnaie delayed germination

Araliaceae, anatomy 237
Araucariales 225

s of new genera, species, and varieties are printed

Araucarians, ancient 498, Seward and
Ford on 224
fed E. A. Newell, on history of ferns

227
Archegonia, of Dioo
Archegoniatenstudien, “Goebel 395
Arni

tk: c; — of 226, 312
pia of water

Ascocarp of eo cen 45°

Ascomycetes, ascocarp-formation 450

Assimilation af tees nitrogen 159

Association Internationale des Botan-
istes 160

Aster 2

Atkinson, George

Avena fatua, del ayed niiieaon 284

Axyris ama we i Sa delayed germina-
tion 279

Azotobacter 233 °

B

Bacillus Nicotianae 227, Olea 301
Bailey, L. H., personal 503
Whi an ee 80

ee W. hs on Fy dows ae 238
Barber, C. A., on root parasitism 317

Barley, proteids i in 15

Barnes, Charles R. 61, 72, 75, 76,
145; 150; ¥55;° 203 soe iss 333; Hi
236, 311; aS 395» 398; 399; 494, 499,
502; perso

as W., personal 320; on evolution

501; a hytsids6 7

Bean, i

ae Rudolf, on Heloatidesdipe 943

spores of Riccia
Beihefte patie Botanischen Centralblatt
240

cage we .
mags ee

, Ma Srerees ¢ on sages pa 2 157
Bene! e, Emily, on Carpinus pe
Bidens” Coreopsis p
Biffen, R. H.,

perso
Sacked ug. rae di botanica
generale 311

595

506

cP shiek station, University of Montana

Biot
Blas, a H., on apogamy of Dasy-

Sink Vernon H., personal goo

Blakea anomala 29

Blakeslee, ASB OT; gem 239; on
zygospore germination I

Blanchard, W. H., work of < 225, 226

ea of rice 316

. H., personal

Bite Frederick W. 1 personal 160

Bonnierella 237

Bonser, Thomas A., — al 80

Boodle, L. A., pers = 400; on monoe-
cism of Funaria

Bose, J. Plant popone 14

Boston jaeee Natural History, Walker
Prize (1907-8) 320

Botanical Geaste date of publication

a, New Yor!
meeting 320; of rc i ep ‘anniversary
2

are obliquum, reduction and
synapsis 229; prothallia and sporelings
OH spore formation 235
— . garis, temperature and toxic

Boutelous formation x 26, 179
- Bower, F. O.,
Brand, Charles Ss on a new red clover

317
Brandegee T. S., gift of herbarium 504
Brasenia purpurea, embryogeny of =
Brenndate: J. F., on —— cultures 3
pathos sweet co mm 69
British Association, grants for botany 319;
‘Section K 4
pees L pcos of 225
Secoke Charles 359
Brotherus, he F., work of 223, 226
, H., on Botrychium 73
6

Bu

Buller, Aa
n Polyporus

Wotan. L. 38 personal 319

Butters, F. K., work of 229

th of 79
notes: on dry rot 78;

Cabomba piauhiensis, embryogeny of 378
Caesalpinia 225

—— - H., personal 319
Canavali

Caprification 78
Capsella Bursa-pastoris, delayed ger-
mination 282

INDEX TO VOLUME XLII

[DECEMBER

Cardamine, me ee 50; imcana 50

Cardiff, I. D., work of 235; perso aa 3195
on reduction ae synapsis 22

Carex 226

rae and photosynthesis 23

Carpinus, double fertilization 1 £50

co ped e of Polysiphonia 406

Cassia 225
Castalia ampla, embryogeny 379; pubes-
7

cens, embryogeny 3

Castilleja purpurascens 146

Celastrum scandens, myccrhiza on 212

Centroso a Polysiphonia 429

Cereus, = ise 65

Cest

Chamberlain, Ca FO 3 7S 2059 2
22,220, 22h. 23 . a personal 239

Claracea ae, N.

Cheeseman, etouas of the New

g
Zealand Flore 495
Chemistry of plants, Czapek on 6
ao — ium album, se germina-

pe an dlapase 316
penwanse: adsorption 499; formation a
Christensen, C., Index Filicum 63, 3

sy
ee reduction, Polysiphonia 430
Chrysle = Aca, ogi; 98;-155

Cicuta, poisonous 232

eye C. B. 502; death of 239; sketch

400 .
Clematis plattensis 52
, G. P., on diseases of bean and
talc 63; Ustilaginales 497
Cloiselia 156
Coccolobis 225
Cockayne, L., cee 240; on subal-
rub 2

: ed — 269

yc relations 237

Color, dation 235

Commeli snide anatomy eg

Conard, Henry S., personal 1

Congress of Arts and Saad eee
papers 312

Coniferales, new genus 226

Conostegia doli 294; rhodope-
tala 295; vulcanicola 295

Contebutors: Atkinson, Geo
Barnes, Charles R., 61, 72, 75, 76. 78,

148, ee 155, 223, 227, 232, 233, 235>
236, 311, 316, 395; 398; 399 494, 499,
02; Blakeslee rs Ba

Charles 359; nace eee | 6s,
73> 75) » 222, 229, 235, 321;
Chrysler, M. A. 1, 71, 78, 155; Cook,

Melville T. 376; Coulter, J. M. 63, 67,
ee 74, 75, 76, 78, 150, 156, 58, 159)
2, 223, 224, 227, 228, 230, 231, 232;

TES NS a I eee ee

Pe TY el! al” ee a ee a ere ener ree =
je ae i cs 5 A eb ie Sd A re a Nee hd ap ha a Cie

1906]

233, 234, 235, 230, 237, 238, 312, 314,
16, 317, 318, 393, 395, 495, 496,
70, 72

265; Day, Ed . 157; Frye, Theo-
dore C. 143; Ganong, W. F. 81; Green-
man, J. M. 146; Hasselbring, H. a
65, 76) 78 » 153, 154, 159, 226
231, 313; 315) 4975 “te E. J. 59; Jef-
frey, ffm. BEE 3 ;

127) ee :* 593 Peirce,
Pp mond H.

Geo 55; Pond, Ray

158, 237, 318, 394, 398, 399; Shantz,
23 Sa , 179; Shreve, Forrest 107;
Shull, George H. 60, 66, 68, 69, 74,

500; Smith, Clayton O. 301;-
Elizabeth H. ue Smith John Donnell
292; en Ra 215; Wilcox,
E. Mead 63, tg oe 238 316,*317,
318; Yamenouth Shigeo

Convolvulus

Cook, Melville 1-376

Copeland, E. B., on — relations of
coconut 2375 work of 226

Corn ni ing

Correns, C. E., on hybrids 66

Cortinarius _mycorhiza-producing 208;

Coulter J. uM. 63, 67, 71, 74, 75) 75 78;

156 ? 158, 159, 222, 223, 224, 227;
ae 230, 231 A3% 233, 234, 235, 236,
237, 238, 312, 314, 315, 316, 317, 318,

393» 395) 495) "496, 497, 498, 502; work
of 312

Cy 2 — nal 2
, on i a apples 157,

Cra rataegus, delayed a 284
Crocker, Wm. 70, 265
Crossandrella 502

rossothec a Hoéninghausi 314
Cuenot, on hybrids
ass urbitaceae, — >

cads, American fossil sie

adichete 70
Cy Seecosus | eaves 235
Bitakiines explodens, pollen tubes 234
- xed 312; anatomy 71
Cyperus 225
a. fasciculatum 48; Knightae

a4 .
origin 71

pew pe 416

Czapek, Friedrich, personal 79; Bio-
chemie der Pflanzen 61; on geotropic
stimulation 398

D
Daikuhara, G., work of 226
Dalla Torre, C. G., Genera Siphono-
gamarum 498

INDEX TO VOLUME XLII

5°97
arling, Chester A., aaa 503
Das n, apogam
Bradley i meee 319
Da "edn ard
Deatbanatit dieraal 397
DeCandolle, Casimir, personal 400,
593
Delphinium Cockerelli 51; poisonous
232
Delpino, Federico, pagans 80
Dendropanax querceti 297
Department of Aaiclture appropriation
160; Office of Experiment Stations,
progress of forestry 50 “
Detmers, Freda, personal 79
Deuterghem Oswald de Kerchove de,
eath of 319
DeVries, Hugo, personal 503, 504; work
of 312; on Svaldéf 500
Diandrolyra 226
Dia aoaee parasitica 316
Diatomin 235
Dineana: esi a matter 235
Dichondra
Dictionary, ics Bie
Diels, work of 223
Dioon edule, age 322; archegonia 3443
egg 349; female gametophyte 340; in
the field 322; aspore membra
341; megasporophylls 328; nucell
334; 0 ate cone 324; female gameto-
hyte 321; testa 331; -_ 324
psi worl 23%, 337,; boo 227;
an Cereus 65; a stnut 316;
Seas 317; Forsythia 76; ginseng
5; guava 64; in Nebraska 317; ole-
ander 301; potato 64; rice 316; tobacco
64, = 313; tomato 64
Dondia 225
Dorfler’s ‘ Portra

ts of botanists’ 496
Double feriization in Carpinus 156
roserace
Drude, "O» gee of 312
ie
78
tt dee B. M., work of 3
Duvel, J. W. T. on vitality “of seeds 72

Earle, F. S., persona
Eaton, A. A., on seas IE of southern

Elaeocarpus S hoastas 240; Hookerianus

240

Eleocharis 225

te ja megaloma 3 317

Elmer, A. D. E. 502; work of 223

508

Embryo, pin gape 370 ai 7
racenia 117; emb Nym

aeaceae 377; Sa cenia 11
Endosperm, Nymphaeaceae 382; Sar-

racenia 1165 self digestion of 7
Engler, s Pflanzenreich 63, 223;

howe
a. ern me Pflanzenfamilien 223,

395
Entomophthoraceae, cytology 236
y 227

sonal 8
Erys iphe, — sleninsii 315
Erythradenia 159

Etiolation 318

Eupatoriae, Robinson on 159

Euphorbia Aliceae

Euphorbiaceae, seeds 77

Evans, Alexan ane W., work of 22

Evol ee to Committee, 501;

n 60
Ewart As a on ascent of water 152

F
Failyer, George e “ie on absorption of
solutes by soils 3

Farr, Edith M., work of 226

Fernald, M. L., work of

Ferns, history 227; © iat t 496;
Philippine 226

Fertilization, Sarracenia 115; Polysi-
phonia

Ficus 502

Field Museum of Natural History, lec-
tures at 319

Fink, Bruce, pe

Fischer, Hugo, starch 157

Flahault, Charles, personal 239

Flora, change in publication 400

Florida, pteridoph 31

Ford, Sibille O., on Araucarieae

a nascent, of Misco beach i

a a

mbronia, gee, peers 36
esac : lium. um-fangus 159
tsch, F. o on problems in aquatic
er ology 2
Frye, Thesdne Gi2ay
Funaria hygrometrica, monoecism 233;
rhizoids 50
Fujii, K., on nutrition of gymnosperm
eggs 230

G

Gaidukov, N., on color of algae 233; on
the ultramicroscope 223

INDEX TO VOLUME XLII

[DECEMBER

Galls, induced by peenonpomanetns 153
eoaeae ee Bloor 321, 340
Ganong, hot

Gatin, C., oa ermination of — 234

Geotropic iienuintio n and position 398

German Bot ign Society, nna fe
anniversary

Ge Jag er fen istry delayed
265; fossil spores 238; ie
235; palms 237; pollen

Genera Siphonogamarum 489

ee G. H., on poi s plants 232
Goebel, K., _Archegoniatenstadien 3053
work of 3
a b. work of 156
Grafe, V., on scion and oak 399
399

r
Grama grass me es 26

ma aap
Gre so rs A Os ry Ptelea 498
Green 6; ao her 319

Cabene: one on maturation mitoses

Griggs, Robert F., personal 79; work of
229

po tee. fe ae — with hand lens and

Gr sori kee of light 318
a ala, lle ial ane from

Guava, disease

64
Gymnosperms, Bennettitales 222; cy-

S

- origin of cy-
cads 71; Phyllocladus. 234; pollen of
= 7e sperms of Cycas 73; Wel-

7
ae Pip oe eo alls 153
Gynodioecism and append 74

H
Paberen G., personal 80; on n photo-
tropis

Hall, John G., args 239

Hall, C. W., work of 2

sailed B. D., on ae ae corn 69
Hamaker, J. I., on zygospores of Mucor

7
Harper, M., work of 156
Hascalbeine H. 62, 65, 76, 78, 135, 153
154, 159, 226, 23s 313) 315» 497
Haustorium of
Hawkins, L. Pee nal 79
frsecinen, daayed per germination 284

1906]

Hayata, Bunzo, work o
Heald, F. D., on black st a apples 373
on disease of cottonwood 317; on plant
es i braska 317

Fe me er ne Reece
re ye

ee
~n
o
ig
wn

Be Hed -
a Se circcsicr, C. Fr, f 79
a erthold, on meena of free

Heliot: Soria 225
Helminthostachy spores 74
Heller, A. ork of 156

, Hints and helps for
young ee 6
Hemsley, W. B., personal 400; on Juli-
aniaceae 2
Herba — a. of Illinois 400
roi Oa tk

y;

Des

_ Heterospory, os in Sphenopbyun 158
oy d gynodioecism

‘Hibiscus cae,

Hieracium ng apogamy 31

Hill, EJ. s pogamy 315

Hill, 5 - aa parichnos 234; on Piper-

Hollick” A, on “gesiatee! i awe 498
. Commeli

Im, ‘Theodore €, ceae 498
Holway, E.°W ae 7 aevcan
Uredinea
Homophytic, new term 166

D. von of ht 335: On

Huber, J., Arboretum 97
y> a si iy OL oo of

Jamieson, Thomas, on fixation of nitro-
gen 155

INDEX TO VOLUME XLII

509

Japan, eg Station Bulletin 226
btn, Te S 312
Jeff E. C. 1; on Brachyphyllum 499;

la ot

I
Aa Bes n germination of pollen 77
falas 236

K

Kahle eat L., on osmosis and osmotic

Keutmeu ; 8

Kern, F. D., w of 226

Kew Herbarium 239, 400

oe oe on microsporangia of
pterid

Keicwood, sie om bs, on pollen tubes of
Curcur aor guna

Kneiffia

— "Pa Handbook of flower pollina-

Kohl, FE G., personal 240; on diatomin
235; on tr gee ce by carotin 232

Koorders and Valeton, Bosmeostent 6 op
Java 3

Ké mincks, “wax personal 319

oe S., on anaerobic respira-

—
Kranz F., work of 156
Piece ky T., on respiratory en-
zymes
Kiister, Ernst, Vermehrung und Sexu-
alitit bei den Pflanzen 222

L

sees eho a
Laccopeta

Lactarius ti pee

Lamarlitre, L., pay Seon de, on Gymno-

Lamprothyrsus 15
—— Scribner, F., work of 226
, W. J. G., personal 239, 319
Tasioak 225
., on ascent of water 153

Larmor,
Lawrence, Lr H., on A ipa scab 238
Sy A.A penal 23

ake n Philippine botany 223

Leaves, siuidaaes ous in cycads 235; of
Sarracenia Ir

Lentinus lepideus,destroying pine blocks
8

ae in, W. W., on mechanics of se-
cretion 15
Lepidium Z

ionis 50
Lepidostrobus, megaspores 238

510

——— "esi 49; Lunellii 40;
Light nang praet wth 318

Lignier, - on fossil roots of Sequoia 237
Lilium,

-» on scion and stock 399;
cc meeines ogie 304
» work of 312

personal “#8
ongo, B., on bicer sea n 78
ee P. Ko nrad, on abitoodel cells

st) ome ee oe iiber Descen-
denztheorien

Lupinus, stint 232
Lyginodendron Oldhamium at
lorence, personal 3

yon:
Lysimachia vulgaris, detieved germina-

M

ee age i 2 ANS i sidan 79
achida, S., work of 226

Macloskie, George, personal 79

MacMillan, Conway, personal 79

Macrozamia heteromera, dichotomous
leaves 2

Mann, Albert, personal 503

Marchantia polymorphia, sex 168

Marsilea 225

Ma "eng 2 A., on pollen tube of

Houstonia
sean a personal 503
Maytenus 2
Genin ‘Lepidostrobus 238;
brane, Dioon 341; a
rik set is lags ebay n 328

mem-
a 10g

} m 1
Mesa, eats of Pike’s Peak 16, 179

Mesopanax 2

Merciten 22

Metcalf, H., on blast of Tice 3

Me tg : Arthur, on thermal eee

Michigan, ecological suryey 230
locama 2

Miconi nutans 29:

Micrampelis lobata, pollen ‘tubes 234

re pteridosperms 314;
Sarracenia 108

Micecusien Sarracenia

Mildews, infection experiment 315
Mitoses, Grégoire o

Mitten, William, oe of 400

INDEX TO VOLUME XLII

[DECEMBER

Miyake, on sperms of Cycas 73

pra igh ia temperature and toxic
—

Mase m of Funaria hygrometrica 233
agra cotyledons, corky cell-layers 155;

Moniniens guatemalensis 294

oss, rhizoids 502
Montan biological ‘station 80
— feril oliata 49; Viae 48

oore, S. ges work of 156, 226

oe inaiias 154; sex 16
temperatu _ re and toxic action 361;

ZYgos S77
Miiller, Heinvich, on cutinized mem-
branes 1

Murrill, W. A., on chestnut disease 316
Mycorhiza, produced by Cortinarius 208
Myroxylon 225

N

cs aramege de — diseases 317

Nelson,

Nereorysts Soe ecology 143

New Brunswick, nascent forest 81

New Ze sland — n Bush 240; sub-
alpine

Nustaia grafting 3993 varieties 399

Nitrogen fixa

tion 1 15 5, 159
Norton, J. B. n potato diseases 64
ees cisaie i in Anthoceros 55

Nuc Dioon
Nucleolus, Polysiphonia 426
ymphaea 156; advena, embryogeny of

Nymphaeaceae, embryogeny of 376
O

Oaks, distribution 59
Octotheca 2

irae —— disease 301
Opercu 318

eared germination 235
Ophryosporus 159

Opun

Orietons, Pee Be
Oste rwalder, A., on ‘danas of Forsythia

Oudemans, C. A. J. A, eae of 319
Overton, James Bertram

Ovule, Dioon 321, 339; Saracuiie 109
Oxygyne 6

1906]

Py

a. I 56

— ag si
227

seal 80
26
rams, 7 319; Abro
y, L. es Bailey
am 239;
B = 20;
Blakeslee, A. F. 239; aie g Vc:
Bli +41. 563; Blodgett, FOE.

160; Bonser, T. A. 80; Boodle, L. A.
Franz 79; Burlin-
a Dean,

Czapek, Friedrich. 79; Darling, pv

ter A., 503; Davis, Bradley M. 319;
DeCandolle, Casi 400, 503; Del
F erico Detmers, Freda

4 S., 239; Errera, Léo 80; Fink,
Bruce 79; Flahault, Charles 2 395 Glee

. 230; 3105 Lawson, A. A. 230;
ner, Th. 80; Lyon, Florence 319;

793 closkie,

27 VE Millan, Conway 79;
Mann, Albert 503; Matsumura, J. 503;
O. 80; T, ond,

d : in, 5035

: Reed, Howard S.

239; Rowlee, W. W.

320; Schmidt, J.

Sc! rmann von 80;

e, Wil Scott, D. H.
00, 503, 504,5 A. C. —

79, 400, § ; Seward,
‘Shantz, H. L. 79; Shreve, Forrest 1
Tangl, Eduard 80; Thaxter, hae

INDEX TO VOLUME XLII

511
5035 peeing A William 319; Uhl-
, Os sca te derwood, L. M.

Wi
mack 320; Wenschie, Otto 80; ’ Wylie,

Me Le
Pfla nzenfanilin 223, 395

Pflanzenreich 63, 22 :

efter, Ww. on ascent of water 150
sona

rassges 53; Lewisii

niti

-hilippines, eas 232

Photosynthesis cor by carotin 232

Sette 39

> h s nitens, sex 167

nyllocladus, morphology 234

->hyscomitrium pyr Toeetse. sex 167

Picea, ane 76

ike’s Peak, mesa region 16, 179

Pilger, R., work of 1

PIPET, Charles V., Flora of Washington

~_—

393
oe arseti = 75

Piquie

Pi feel. eee I

Pityoxylon scituatense 11; sta 8
lantago major, delayed germination 282;
Rugelii, delayed germina

Plant re: care “ia on 14

eons —
owman, A. = on anatomy of Cyper-

cet caceyaone 240; spicatus
240; totarra 2.
Poisonous ‘iteto plants 232
Pollen, germination 77; tubes
bitaceae 234; tubes of Houstonia 318;
Sarracenia 113
Pollination, Knuth on 494; Sarracenia
Pollock, a B., on pollen of Picea 76
Pol $ squamosus and timber decay
2 26
han vatrages = ig of ger-
Ms 432; 406, centro-
some i
cystoc 416; = 416; nu-
cleolus 426; procarp sperm:
genesis 409; spindle y sna a8:
tri € 413

ee os jae botanists 496
Postelsi
Potato, yee 64

512

Prain, D., personal 503

Pri a ae H., on ssihtchyilphiiais 77

Primofilices 228

Pringle, G., pers

Prize by German Botanical ‘Society 79

Procarp of Re he

Prophyllosa

Proteids, in a ripening barley 158

Protodam

Prunus Capollin beciptibrtdee 293; igno-

Ptelea 498

Pteridophytes, sex 168; in
7

pdadoten microsporangia of a

puanet, R. C., on evolution 501;

hybrids 67
Pythiacystis citrophthora 221

Quercus ellipsoidalis 59; palustris 59
R

Rabe, a on drying of seedlings and
spore

art "Biaride on roots of ivy 318
anunculus 226; digitatus 52; ‘Be 52;

maximus 52; typ 52

Raunkiar, C., on inheritance of hetero-
morphism

Red clover, a new 31

Reduction and synap: 29

Reed, Geo M., on infection experi-
ments with Erysiphe 315

Regt, Howard 5 » personal 79; on dis-

evans
Re ss sein ” Kiister 22
poems anaerobic mn 973 enzymes 227
Bi ni’s “Dizionario di
a fat generale” 311; Bose’s “Plant
response”? 148; Cheeseman’s ‘“‘M

“ Natirlichen
G

oebel’s

scope” 62; Her
and ey: for omni
gardeners” a Im’s “Co: ——
; ae “North Am
Uredineae ~ 150; Huber’s oy

INDEX TO VOLUME XLII

southern

[DECEMBER

Amazonicum” 497; Husnot’s
nuth’s ‘‘Hand-

Pflanzen” 222
anzenphysiologie
otsy’s “ Vorlesungen tiber
scendenztheorien” 60; Piper’s
of Washington” — 393; Ry erg”
« Syllog = de se a 3933 Geaenidoss

“Syllo ungorum” 62; Schneider’s
pies Handbuch” 150;
6:

Hy ”

De-
“Flora

7 Kongress in Wien” (1905) 4933
ieland’s ‘American fossil cycads”

Rhizods, moss 502

Ri
ne ae a bush 240
Riccia paps Spors 228
Rice, blast 316
Riddle, Tice W., on Entomophtho-
race
ante yerg on Phyllocladus 234
Robinson, Bs on Eupatorieae 159;

ork of 3
Ritithsdn, é *’. ., on Chareae 159 F
Rondeletia a aetheocalymma 2098; stachy-
oidea 298; Thiemei 299
Roe apical meristems 238; English ivy
3185 fossil Sequoia 237
Ros rsonal 239
Rjoendlal G O., work of 229
Rate prs 317
W. W., personal 79
Rubiaceae, Philippine 223

Rubus, 156, 225, 2

Ruthven, a +. on aca of biota to
ensirqumer

Rydberg, P. te Flora of Colorado 393

S
Saccardo, P. A., Sylloge Fungorum 62
t. Louis Congress, botanical papers 312
Salomonia biflora, reduction and synap-

9
me She — on Carpinus 157
fe ie n, on flowering of fruit

ees 31 -
sda, haustorium of 317
Sarracenia ae ay development and
anatomy 107

aunde personal 320; on evo-

lution 501; on hybrids 67
Saurauj i 292; ovalifolia 292;
su ps a — adscendens 53;
ensis 52; subapetala normalis

1906]

Scab, apple 238

Schaffner, mes 1. H, death of 80
Schizomeryta 237

Schjerning, H.,.on Bagi . ie ae
Schlechter, R. 502 156 6 226
Schmidt , Jo ohann ree ae

Schneider, C. K., Ilustriertes Handbuch

Hes
Schoene, Kurt, on moss rhizoids 502
Spsiner. Oswald, on absorption of sol-
utes Pe soils 398
Schrenk, Hermann von, personal 80
ae ie est m4 sterilized soil 502
Schwacke, -Wilhelm, personal 80
-., Joep on seeds of Euphor-
biace
le cden, S., on ascent of water 150
Scion and stoc 399
Sclerotinia fructigena 317; on Forsythia

eae 7 G., on apical meristems of

ahem personal 79, 400, 503, 504;
nating spores in Stauropteris

2
Scott, wage on megaspore of Lepido-

strobus

Scrub, in os — 233

Secretion, mechanis
Seed coats, rdle in anid germination
Euphorbiaceae 77; Sarracenia
“1173 arent y 72
= g 70; Sarracenia 117
- Selby, = D. on ‘tiolaton n 318
Sen Farriae le

necio

Sequoia, fossil roots

Seward, A. C., person nj 503; on Arau-
carieae 224; on Cycads 235

Sex, differentiation of 161; in Mucorales

eee
Shantz, H, L. 16, 179; personal 79
Sheldon, J. L., on mummy disease of

guavas
Shreve, Forrest a aera 160
nad George H. 60, 66, 68, 69, 74, 500
_ Slosson, Margaret, tee rll grow 496
Smith, Clayton O.
Smith, Elizabeth a
Smith, oat Donnell
Smith, Ralph E. 215; ae tomato disease
64

_o egies bald, work of 312

Soils, absorption of solutes 398; steril-
ized 502
oe, cultures 399: physiologically

27

Cereus 65

INDEX TO VOLUME XLII

513
erms, Cycas 73
Sphagna, lime and 236
Sphenopholis 226
Sphenophyllum, sri aed 158
Sphenopteris Héninghausi 314

Spindle formation, Polgeiphions 428

Spiranthes 226

oni Bote hium 235; fossil germi-
ae 238; Riccia glauca 228;. The-

A5e

Sporobolus 1

Sporodinia = sex 167

Stapf, O., k of 226

Stangea 1 ie

Starch, nature 157

pepe -Obthaaala: germinating
yank:

res 2

ok op on ascent of water 151

orairdcenth 225

Stenandriopsis 156

Sterigmatocytis nigra, temperature and
6

stevens, f. ce on tobacco wilt 6
Stevens, W. c. on spores of mowyckasd

235

Stock and scion 399

Stoklasa, J., on oe 233

Ss, on trition f gymno-

sperm eggs” 230

Strasburger, E., on ascent of water 150

ak yg wot aX 237

Sval6f Experiment Station 500

Synapsis and reduction 229

Taiwan:
Tang 55 rote personal 80
angium Scotti 314
hei erature, and flowering of fruit trees
Te

31 18: and resis ction
Testa, Dioo Zamia 334
Tetraspore, Poleinhons 403, 420
Thaxter, nog nd, personal 503
Thayeria
Phecotheus Pelletieri, ascocarp and
pore-formation A
Thermal death- 397
Thlaspi — pach germination 282
Thoday, D., on heterospory in Spheno-
hyllum 1 =.
Tibouchina — 293
Timber, decay 23

Tischer, G., on sierile a ie hybrid -
Tobacco, disease 64. 313; varieti

399
— mato, disease 64
Townsonia 496
Toxic action and temperatur
Trees, Amazon region 497; — 312

514

Trelease, William, personal 319
Trichogyne of Polysiphonia 413
Rose oe terreum, Se mycor-

Trifolium pratense foliosum 317

225
Tether E., on elgg 67; on Men-
delism in agriculture 6
Tswett, M, on ilocoriiil 499
Turgor i in yeast 316
boa 67

Tum

U
Uhlw eine se — 240
pei ~~ of 156

eobryum
Ultamicrosope, hen a AA on 223
I WOoe » pers 79
Gaaveniiy: California, Vesbietisies 5043
of Illinois, herbarium 400
ko

: is
ng, A., on ascent of water 151
Usher, F. L., n photosynth | 77
Ustilaginales "of N. Am. 497
Ustilago Shiraiana 227

Uyeda, work of 227

Van Hook, J. M., on diseases of ginseng
6

Van Tieghem, Ph., on Araliaceae 237
Vascular system in

ongress in Wien (1905) 493

Vienna 237 ess 49

Vilmorin, Maurice An personal 320
Vilmorin, Philippe L. de, personal 1
Vines, S S H., personal 400

Viola 225

INDEX TO VOLUME XLII

[DECEMBER 1906

Vries, Hugo de (see DeVries)
W
Waite, M. B., ee iy —

ebiated Prise, s
Ward, H. Ma eal death of 239; sketch

of 40 re)
Water, ascent o
Welwitschia, Ska on 67
Went, F. = F, C., on apogamy in Dasy-

en
lirion

Whetzel, i, H., on diseases of beans 64

Whitford, H. N., on Philippine forest
vegetation 232

Pacey Cc. Pg Oe ork of 312
yee sgh ne R., on American fossil cy-
cads 2
Wiser, ae work of 312
Wilcox, E. Mead 63, 157, 232, 238, 316,
17, 318
Wildeman, E. de, personal 80
Wittmack, L; personal 320
Worsdell, W. ce, on Sgr 71
Wainsche, Otto, ‘personal 8
ylie, R. B., personal ae
x
Xanthium, delayed germination 269
¥
Yamanouchi, Shigeo 4o1
Yeast, turgor in 316
Z
paietaee 3alae A., work of 156, 22
Zaleski, W., che emistry of pes
39
Zamia, t ta 334
Zyga sdevas , poisonous 232
ence of Mucor 77