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THE BOTANICAL GAZETTE

THE UNIVERSITY OF CHICAGO PRESS
CHICAGO, ILLINOIS

THE et it che hea cose PRESS

THE MARUZEN-KABUSHIKI-KAISHA
TOKYO, OSAKA, KYOTO, FUKUOKA, SENDAI

THE MISSION BOOK COMPANY
SHANGHAI

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THE : | 64 6Y

BOTANICAL GAZETTE

EDITOR
JOHN MERLE COULTER

VOLUME LXXIV
SEPTEMBER-DECEMBER 1922

WITH NINETEEN PLATES AND ONE HUNDRED THIRTY-THREE FIGURES

THE UNIVERSITY OF CHICAGO PRESS
CHICAGO, ILLINOIS

Published
September, October, November, December, 1922

TABLE OF CONTENTS

Development of plant communities of a sand ridge
region in Michigan (with twelve figures) - -

Sulphur content of soils and its relation to plant
nutrition. Contributions from the H
Botanical Laboratory 297 (with one figure) -

Effect of autolized yeast and peptone on growth of
excised corn root — in the dark ae ia
figures) - -

Leaves of the Farinosae (with platesI-III) -_ -

Inheritance of fruit shape in Curcubita = hs
(with three figures) - - -

Biochemistry of plant diseases. IV. Proxhunte
analysis of plums rotted ed Sclerotinia cinerea
(with two figures)- - sc em tm ae

“Magnesia injury” of plants grown in nutrient
SOMItIONN «© 6 ee we oe

Heterotheca Grievii the microsporange of Heter-
angium Grievit (with a IV, V, and ies
figures) - - - - -

Early embryogeny of Reboulia pemienenvt ise
forty-seven figures) - -

Specific acidity of water extract and oxalate con-
tent of foliage of African sorrel (with one

Microbiology of flax retting - - - - -
Anatomy of a gall on Populus trichocarpa (with

plate VI) a ee a
Pollination in alfalfa (with five figures) - - -

Protective power against salt injury of large root
systems of wheat seedlings- - - -

W. G. Waterman

Scott V. Eaton

Wm. J. Robbins

Agnes Arber

E. W. Sinnott

J.J. Willaman and
F. R. Davison

W. F. Gericke

Margaret Benson

A. W. Dupler

G. P. Walton

Fred W. Tanner

Karl C. Hyde
F. A. Coffman

W. F. Gericke

PAGE

IIo

I2I

vi CONTENTS

A new fruit rot of tomatoes (with plate VII) -_-

Effect of seeds upon hydrogen-ion concentration of
solutions- - - - - <= Se

Physiological studies of effects of = was kobe on
wheat (with twelve figures) -

Development of the Geoglossaceae (with plates
Vitbes el) Se ee ee eee

A morphological study of the Umbelliferae. Con-
tributions from the Hull Botanical Labora —
298 (with plates XIII, XIV) -

Determination of moisture content of —
plant tissue fluids -

Moisture content of peach buds in relation to
temperature evaluations (with two figures) -

Alternaria from California (with two figures) - -

Basisporium gallarum Moll., a Pe of the
tomato (with eleven figures) -

Ecological factors in region of Starved Rock, Illinois.
Contributions from the Hull Botanical Labora-
tory 299 (with five figures)- - - - -

Notes on neotropical ant-plants. I. Cecropia
angulata, sp. nov. (with plate XV and eight
guts) ~ 9 < +. we oe oe ee
’ Prothallia of Lycopodium in America. II. L. lu-
cidulum and L. obscurum var. dendroideum.
Contributions from the Hull Botanical Labora-
tory 300 (with plates XVI-XVIII) - - -
New South American Asteraceae collected Be
E. W. D. Holway (with plate XIX)- -
Recent studies of iar tage and their of mae
on classification
A method for estimating hydrophilic colloid content
of expressed plant tissue fluids (with one
qe) - = Get see

Growth of plants in artificial light (with two
fparess = ee ee ee

[VOLUME LXXIV

R. Frank Poole

W. Rudolfs

W. M. Atwood

G. H. Duff

H. S. Jurica

R. A. Goriner and
W. F. Hoffman

Earl S. Johnston
D. G. Milbraith

G. B. Ramsey

Frank Thone

I. W. Bailey

E. A. Spessard

S. F. Blake

Wm. R. Taylor

R. Newton and

R. A. Gortner

R. B. Harvey

210

VOLUME LXXIv] CONTENTS . Vil

BRIEFER ARTICLES—
Sagenopteris, a mesozoic representative of the

Hydropteraceae (with one figure) - - E.W. Berry 329

A bisporangiate sporophyll of Erase sage
lucidulum (with one figure) A.W. Dupler 331

imple apparatus for oe es
te (with one figure) - E. E. Hubert 333
CURRENT LITERATURE - - 114, 221, 335,452

For titles of book reviews see ie ‘tithe
author’s name and reviews

Papers noticed in “Notes for Students” are
indexed under author’s name and subjects

DATES OF PUBLICATION
No. 1, September 15; No. 2, October 16; No. 3, November 23; No. 4,
December 21.

ERRATA
Vor. LXXIV
P. 57, line 10, for higher read lower
P. 181, footnote line 4, for Fivprusz read RiInDFUSz
P, 300, line 7, for even read do not even
P, 316, fig. 1, lowest filled circle of 1921 curve should be open circle of 1919
curve

VOLUME LXXIV NUMBER 1

THE

BOTANICAL GAZETTE

September 1922

DEVELOPMENT OF PLANT COMMUN ITIES OF A
SAND RIDGE REGION IN MICHIGAN
W. G. WATERMAN
(WITH TWELVE FIGURES)

Plant synecology is the study of the relations of plant communi-
ties to their environment. The subject may be divided into three
major sections.

1. Morphological and physiological synecology.—The physiog-
nomy, ecological structure, and floristic composition of plant com-
munities and their relationship to the factors of the environment.
This includes not merely an enumeration of the species and
ecological forms present, but also the sociological value of the dif-
ferent members of the community, as suggested in the following
topics: abundance, dominance, affiliation, genetic _ importance,
constancy, etc.

2. Geographic synecology.—The distribution of plant communi-
ties, with special reference to the influence of the factors of environ-
ment.

3. Genetic or dynamic synecology.—The study of the develop-
ment of plant communities on unit areas as the result of the action
of biotic factors, modified by physiographic influences and by
changes of climate.

In the early days of ecology, the distributional phase of synecol-

ogy was more evident and was followed with almost no suggestion

2 BOTANICAL GAZETTE [SEPTEMBER

of the others. In recent years the other phases have been increas-
ingly studied, but all have generally been combined in a more or
less haphazard fashion. In a geographically extended treatment of
the subject, the distributional (geographic) division may either
precede or follow the developmental (genetic) division. If the
communities are considered merely from the standpoint of their
floristic content, their distribution may be studied first, and this
has been the historical order. Plant geography has been studied
with increasing interest since the days of von Humsporpt, and it
is still an important branch of synecology. It is evident, however,
that the distribution of communities identified and named in
accordance with their position in a developmental series (associ-
ations, formations, etc.) cannot be carried out adequately until a
genetical study of those communities has been completed. In a
limited area the study of the distribution of communities is cor-
respondingly limited, and is of value only as it helps to determine
the developmental relationships of these communities.

As genetic synecology is the most recent branch of the subject,
and its content is not yet fully organized, a brief historical statement
will be in order at this point. Cowters (3) was the first to form a
comprehensive system based on the dynamic element in plant com-
munities, as a result of his difficulty in classifying the communities of
the Chicago region in accordance with WARMING’s principles. He
was so strongly impressed with the influence of the physiographic
factors that he outlined his system on that basis. Later (4) he
recognized climatic, physiographic, and biotic factors as the three
great causes of plant succession.

CLEMENTS (1) pointed out that climatic and physiographic
causes produce succession but not true development, that is, the
building up of a quasi-organism; and that this was possible only
by the action of biotic factors, and especially by the influence of
the plants which compose the different communities. CLEMENTS
bases his main divisions on his climaxes or “‘formations,” his next
division is into primary and secondary successions, and his third
into hydrosere and xerosere, based on the water content of the initial
area. For these divisions he also uses as adjective modifiers the
term hydrarch and xerarch, suggested by Cooper (2). As these

1922] WATERMAN—PLANT COMMUNITIES 3

latter refer especially to the beginning of the succession, they are
more suitable in this connection than such terms as hydrosere, etc.,
which apply to the moisture content of the whole succession, because
in most cases the initial moisture condition does not persist, and the
substratum generally approaches a mesophytic condition. While
this classification may be logically defensible, CLEMENTS does not
give sufficient consideration to the fact that the actual lines of
development are determined by the nature of the substratum, that
the floristic content of the pioneer stages is absolutely different in
clay, sand, or rock, and that it is only as the seres approach the
climax stage that they begin to converge and to resemble each other.
Furthermore, standing water should be regarded as a type of sub-
stratum, because its pioneer stages are practically identical in ponds
on rock, sand, or clay, and are quite different from the pioneer
stages of wet sand or clay, to which stages the term hydrarch
should be restricted. The subdivisions of the primary succession
(prisere), therefore, should be sand succession (psammosere), clay
succession (geosere), rock succession (lithosere), and aquatic suc-
cession (hydrosere). The first three successions have wet and dry
initial stages (hydrarch, xerarch). It is evident that this classifi-
cation does not distinguish the many types of substratum containing
mixed sand, clay, and gravel. It does not seem, however, that these
are sufficiently well marked or sufficiently different as to vegetation
to warrant establishing one or more additional seres for them at
present.

The terminology of the units of genetic synecology is being much
discussed at present. It is generally agreed that the fundamental
unit in the developmental classification of communities is the associ-
ation. At first this was defined in terms of the habitat, but in 1921
NICHOLS (7), as a result of several questionnaires sent to eighty-five
ecologists, reported at the recent meeting of the Ecological Society
of America at Toronto that a large majority of the ecologists con-
sulted favored the following statements: (1) That the term plant
association be recognized as applicable both to the abstract vegeta-
tion concept and to the concrete individual pieces of vegetation
upon which this concept is based; (2) that plant association in the
abstract be defined somewhat as follows: an ecological vegetation-

4 BOTANICAL GAZETTE [SEPTEMBER

unit characterized by an essentially definite physiognomy and
ecological structure, and by an essentially definite floristic composi-
tion as regards dominant species; (3) that plant association in the
concrete be defined somewhat as follows: a plant community of
essentially uniform (or homogeneous) physiognomy and ecological
structure and of essentially uniform (or homogeneous) floristic
composition as regards dominant species. This simply formulates
the more or less unconscious practice of most ecologists, who, when
speaking of “‘a Scirpus-Typha association” have a concrete com-
munity in mind, while “the Scirpus-Typha association” of a certain
region is plainly an abstract concept.

The next higher unit is also generally recognized as the forma-
tion, but there is not yet the same agreement in regard to its content
as there seems to be for the association. The following brief survey
of the progress of opinion in regard to the formation is summarized
from TANSLEY (9). According to the definition adopted by the
Brussels Congress, the formation is composed of associations which
differ in their floristic composition, but are in agreement (1) with
the conditions of the habitat, and (2) as regards their growth forms.
TANSLEY says, “‘ Though this concept is apparently accepted by most
European phytogeographers, it has little real hold on actual concrete
research because it is abstract and one sided.” In 1907 Moss (5)
proposed a unit, later embodied by Tanstey (8), in which all
associations developed on the same habitat or on one of essentially
constant character were considered as belonging to one formation.
Not all the stages of a succession were necessarily included in one
formation. If the habitat obviously changed its character com-
pletely, it was recognized that a new formation had been initiated.
This conception was widely criticized, and TaNsLEy admitted the
validity of criticisms of the habitat element in the definition.
CLEMENTS (1) refused to recognize any formations except those de-
termined by climate, regarding all communities in a region where
forests are climatically possible only as stages in the development
of forest formations. ANSLEY believes that this view has not been
generally accepted in Europe or in America, and feels that the uni-
versal dominance of climatic factors as determinants of climax
vegetation has not been proved.

1922] WATERMAN—PLANT COMMUNITIES 5

NicHots (6) recognized this and returned to SCHIMPER’s dis-
tinction between climatic and edaphic formations. His unit next
above the association was the edaphic, later called the physiographic
formation, which he defined as the association-complex occupying a
physiographic unit area, while the climatic formation was a complex
of physiographic formations forming the vegetation, taken in its
entirety, of any region in which the essential climatic relations are
similar or uniform throughout. This TANSLEy criticized, because
“nothing like a sharp line can be drawn between one climatic region
and another, so that it becomes impossible to delimit ae goes
tions in NicHots’ sense.” TANSLEY accepts CLEMENTS’ “‘associes”’
for all stages which have not reached a relatively stable (climax)
condition, and defines the association as a mature quasi-organism
which is relatively fixed and stable. He then defines the formation
as including ‘‘all the vegetation which is naturally grouped around
the association, determined by the particular collection of environ-
mental factors which ‘make up the ecological conception of the
habitat.”” NuicHots has not published as yet any further statement
on the formation, but in his paper at the Toronto meeting he seems
to adhere to his division of formations as physiographic and climatic.

As a result of a study of literature on formations, as well as
actual conditions in the field, especially in connection with the
preparation of the present paper, the writer has reached the follow-
ing conclusions, on which the definitions of the terms involved will
be based

1. That there is a distinct advantage in omitting from the defini-
tion of the formation all reference to the habitat, as was done in the
case of the association.

2. That it is inadvisable to connect the idea of the formation
with a climax association, because the determination of climax is
one of the purposes of a genetical study, and it is clearly undesirable
to define a term which should be usable from the beginning of a study
in such a way that it cannot properly be used until the study has
been completed. In such a case it would be necessary to secure an
additional term for the community in the process of development.
This is cumbersome and unsatisfactory, as is illustrated in
CLEMENTS’ use of ‘“‘associes” and “association,” which does not

6 BOTANICAL GAZETTE [SEPTEMBER

seem to meet with general approval in this country at least. In
this case there is the additional objection that the more familiar
and convenient term is restricted in use to a minority of cases.

3. That the double aspect, abstract and concrete, approved for
the association be recognized also for the formation. The abstract
concept of the formation, indicated by the use of the definite article,
would thus correspond with the Brussels Congress description, and
would constitute the formation abstract as a sort of ecological
species. The formation concrete might then be regarded simply
as any association complex, characterized by a dominant association
but including all adjacent associations, whether mature or imma-
ture, and other more or less anomalous or unidentified communities
connected with them. Thus the formation concrete in general
would correspond to NicHots’ physiographic formation, although
the habitat is omitted from the definition, and contiguity made
the basis on which the communities are united in the formation.
Individual formations may be named either from the dominant
association or from the physiographic nature of the area occupied.

4. If a unit above the formation is desired, it will be found con-
venient to associate the formations of a region in a larger group,
which NicHots (6), following Scutmper, has characterized as a
climatic formation. TANSLEY has demonstrated the inadvisability
of the term, but the fact remains that the concept is a convenient
one, especially for field use, and the writer suggests that the term
“formation complex,”’ or simply “complex,” be used for this con-
cept. If it be objected that complex is equally applicable to lower
grades of units, and is actually in use with them, a special term,
such as ‘“‘aggregate,”’ might be employed. It does not seem advis-
able to use the term formation, even if qui ied by a descriptive
adjective, for two classes of units of different grade. Indeed this
concept may be identified sufficiently by general expressions already
in use, such as vegetation, formations, or even forest (as in ‘‘ vege-
tation of Connecticut,” “‘formations of the Great Lakes region,”’
“temperate deciduous forest,” etc.).

On the whole, it seems advisable to follow TaNsLey and NICHOLS
in emphasizing the vegetational content of the community and
regarding the habitat as the sum total of the environmental factors,

1922] WATERMAN—PLANT COMMUNITIES 7

and therefore not employing it to indicate any definite portion of
the surface of the earth. There is an advantage in employing a
special term for the ground occupied by each synecological unit,
and the writer tentatively uses the word “‘locality” for the ground
occupied by an individual association, “area”’* for that occupied by
a formation, and ‘‘region”’ for that occupied by a formation complex.

The present study is to be regarded as a preliminary reconnois-
sance rather than as a completed work. Its purpose is to indicate
the lines along which such a study should proceed, and to suggest
some tentative conclusions. It is the intention of the writer to
make a thorough study of the morphology and physiology of these
communities, and in the light of those results to review the tentative
conclusions now reached. This preliminary survey will also serve
to introduce the region to ecologists, and to show the unusual oppor-
tunity for the study of the very diverse communities of a region
in relatively primitive condition. Incidentally the writer regards
the region as one which should be included in a list of regions to be
preserved in their natural condition.

Description of habitat

GrocraPHy.—The region is located in Benzie County, Michigan,
and adjoins on the north the Crystal Lake Bar region already
reported (10). It may be described as a right-angled triangle whose
base is about eight miles long, extending south-southeast from a
point on the shore of Lake Michigan about two miles northeast of
Point Betsie, almost to the town of Honor on Platte River. The
east side of the region is the perpendicular of the triangle, and
extends north from ‘Honor nearly to the town of Empire on Lake
Michigan. The shore forms the hypothenuse, curving slightly to
the south with a projection at the mouth of Platte River. It hasa
total area of about twenty-five square miles, of which perhaps one-
fifth is occupied by lakes and ponds. The region is locally known
as the Platte Plains, although it is composed of sand ridges and hills,
and the general relief is distinctly rolling rather than flat (fig. 1).

The Lake Michigan shore is bordered by a strip of moving dunes
ranging from 200 to 500 yards wide. As the prevailing winds are

* This is an ecological use of the term, and differs materially from its foristic use.

8 BOTANICAL GAZETTE [SEPTEMBER

from the southwest, this dune strip has been protected by the
morainic ridge (fig. 2) north of Point Betsie, and the dunes are
relatively low and do not have the scenic features to be found in
similar areas elsewhere. South of the narrow belt of moving dunes
are found the sand ridges, roughly parallel with the shore, with inter-
vening depressions, some still containing small ponds. These ponds
occur almost exclusively in the portion of the region west of Platte

THe PLATTE PLAINS
SAND RipGe REGION
Benzie County
MiIcHIGAN

MORAINES

Decipuous Forest 727

SAND HILLS DOO

2 cTamarack Cepar/=,= = 232 =
XTENSIONS *77~7 42 FoREST GRASS M EADOW aD
Fic. 1.—Map of Platte Plains sand ridge region

a
“¢
ae

River, probably because of the protection of the morainic ridge
which has prevented them from being filled by blown sand. Be-
tween the sand ridges lies a wide trough of relatively slight depth,
which contains a series of six lakes, more or less completely con-
nected and draining into the Platte River, and three small lakes
draining to the north through Otter Creek.

GroLocy.—This region is regarded as having been a shallow
embayment of Lake Algonquin, whose shores were formed by

1922] WATERMAN—PLANT COMMUNITIES ¢)

morainic uplands. The shore line of the embayment is clearly
traceable along the southern and eastern border of the Platte Plains
as shown on the map. On the west the old shore line, protected by
the morainic ridge, is marked by low rounded knolls, but on the
south and east it still shows the characteristics of a wave-formed
bluff (fig. 3). This feature has been continued by wave action in
the lakes on the south, and it is especially marked on the east, where
it borders the floodplain of Otter Creek (fig. 7). There it still remains
asa steep bank rising 150 or 200 feet above the plains. The present

2.—View toward southwest over shore dunes to morainic ridge which formed

Fic.
the Algonquin shore on the sout

sand ridges with intervening depressions were formed originally as
sand bars by the receding waters of Lake Algonquin, assisted by the
winds, which piled dunes of varying heights up to 100 feet above
Lake Michigan on the successive beaches left bare by the receding
lake. One morainic fragment is found on the present shore line half
a mile east of the mouth of Platte River, in shape like a hogback,
with a very steep forested slope on the south and an equally steep
bluff of erosion facing the lake (fig. 10). The line of hills between
Platte Lake and Little Platte is a morainic remnant exactly in line
with the fragment on the shore. Morainic gravel has been found

ste) BOTANICAL GAZETTE [SEPTEMBER

in at least one spot midway between the two; so it seems probable
that these represent the remains of a moraine which originally
bisected the triangle, and which later determined the location of
Platte River.

ENVIRONMENTAL CONDITIONS.—The factors of the environment
are similar to those of the Crystal Lake Bar region (10), and will not
be repeated here. A study of the soil acidity by WHERRY’s method
is planned for the near future, and will probably yield interesting
results. The variations in soil and moisture content are evidently

3-—View toward the southwest over Platte Lakes, showing Algonquin shore

Fic
line in didsace

of great importance. The substratum consists in the main of
beach and dune sand, but there is a mixture of morainic material
around the edges where moraine clay and gravel were washed down
by the waves of Lake Algonquin and by atmospheric agencies since
that time. The materials of the low morainic ridge which bisect
the area are also of considerable importance, and their significance
will be considered in connection with the migration of the deciduous
forest elements into the sand ridge vegetation.

ile the slight moisture content of the superficial layer of
sandy soil is generally recognized, it has been thought that the

1922] WATERMAN—PLANT COMMUNITIES II

moister conditions of lower layers and the low wilting coefficient of
sand would prevent a serious deficiency of moisture for plants
adapted to that habitat. The very dry weather in the first part of
the summer of 1921, however, apparently caused serious results, al-
though the full effects of these conditions cannot yet be determined.
The leaves of the blueberries and other small shrubs dried up early,
and while the plants were not killed, their vegetative development
for the following summer was greatly reduced. A number of oak
and pine seedlings up to two feet in height were evidently killed.

Fic. 4.—Typical sand ridge vegetation, with Pieris aquilina in center

Similar “red summers” were reported by the farmers as having
occurred at intervals of eight or ten years. It is evident that they
would profoundly affect the development of a dense growth of trees
on these ridges. Various fires, chiefly prehistoric, have also had
an influence. The areas which were affected by these fires should
be determined and mapped, and their influence on the present
vegetation more definitely determined.

Morphology and distribution of communities
MOVING DUNE FORMATION.—The dune vegetation is practically
the same as that of the Point Betsie dune complex already described

12 BOTANICAL GAZETTE [SEPTEMBER

(10, 11), with the important exception that thereeare numerous
groves of Pinus Banksiana occupying depressions just back of the
foredune, and apparently originating in pannes.

SAND RIDGE FORMATION.—The sand ridge area was originally
covered by a forest of pine and oak whose trees had reached con-
siderable size. This forest had been burned before the white set-
tlers came to the region. Many of the dead trees were cut while
still standing, and many of their stumps still remain. A few patches
were not burned, perhaps being protected by neighboring bodies
of water, and these give some idea of what the original forest
might have been (fig. 8). Reproduction has been good all over the
region, and with fifty years’ growth behind it, the forest might be
regarded as half-way to maturity. While strictly this region should
be regarded as a secondary succession, most of the area has prac-
tically been untouched by man, and the development seems to be
well on its way toward a reproduction of its original condition, so
that with the aid of apparently untouched portions it should be pos-
sible to work out the stages of the original succession.

The trees of this formation in the order of their importance are
Pinus Strobus, P. resinosa, P. Banksiana, Quercus ellipsoidalis,
Q. alba, Q. rubra (Q. velutina apparently should belong here, but has
not been certainly identified), Acer rubrum, Betula alba papyrifera,
Populus tremuloides, P. grandidentata, Amelanchier canadensis, and
Prunus pennsylvanica. The shrubs found on the sand ridges are
Cornus stolonifera near the dune belt and Rhus typhina farther south
(fig. 4). In the undergrowth are found Pieris aquilina, Gaultheria
procumbens, Vaccinium vacillans, V. pennsylvanicum, Melampyrum
americanum, and Ceanothus virginiana, with Cladonia rangiferina,
several cushion mosses, and occasionally Selaginella rupestris in the
drier portions. In the more mesophytic spots occur also Pedicu-
laris canadensis, Galium sp., Maianthemum canadense, Diervilla
Diervilla, and Aster cordifolius. Near the dunes are found Artemi-
sta canadensis, Smilacina stellata, Arctostaphylos uva-ursi, A pocynum
cannabinum, Rosa blanda, Juniperus communis, and J. horizontalis.

ASSOCIATIONS OF SAND RIDGE DEPRESSIONS.—The depressions
between sand ridges are small oval bowls or pockets averaging only
a few hundred yards in greatest length. They show all types of

1922] WATERMAN—PLANT COMMUNITIES 13

aquatic communities, from those which are nearly all floating
aquatics to the grass meadow or the swamp shrub thicket. There
are few characterized by a true bog mat, but many contain charac-
teristic bog plants and shrubs. The grass meadows vary in size
from a few yards in diameter to one too yards wide, and one-half
to three-quarters of a mile long; while two others of equal length
are 200-300 yards wide (fig. 11). These are usually bordered by a
narrow shrub zone between the sand ridge and the meadow, includ-
ing Alnus incana, Pyrus arbutifolia, Rosa carolina, and Cornus stol-

Fic. 5.—Chamaedaphne meadow with Picea Mariana and Larix laricina

onifera. With the grasses and sedges in the smaller meadows are
found also Hypericum virginicum and Spiraea salicifolia, while
occasional specimens of aquatics occur, as Jris and Sagitiaria. In
one case a remarkable growth of Lobelia cardinalis covered one acre
of meadow with its scarlet flowers.

The bogs are generally found at or near the border of a lake or
river, and are of two general types, one an ericad heath, the other
a tamarack thicket. The heath type has a more or less continuous
cover of sphagnum with its usual accompaniments: Sarracenia
purpurea, Vaccinium macrocarpon, Drosera rotundifolia, Menyanthes

14 BOTANICAL GAZETTE [SEPTEMBER

trifoliata, Aspidium Thelypteris, and in the wetter portions Typha
latifolia, Iris versicolor, and Phragmites communis (fig. 5). The shrubs
are Chamaedaphne calyculata, Andromeda glaucophylla, Vaccinium
corymbosum, Betula pumila, and rarely Ledum groenlandicum.
The trees if any are scattered, and include Larix laricina, Picea
mariana, and where the substratum is very dry Pinus resinosa and
P. Strobus.

The bogs of the thicket type are covered with a dense growth of
Larix with some Thuja occidentalis, mingled with shrubs of Alnus

Fic. 6.—Long Lake, with pines on sandy point; Algonquin shore line in distance

incana, Betula pumila, Rosa carolina, Chamaedaphne calyculata,
Andromeda glaucophylla, Cornus stolonifera, Eupatorium perfoliatum,
Myrica Gale, and occasional specimens of Cypripedium sp. These
thickets are usually surrounded by a zone of Thuja, sometimes
narrow but occasionally of sufficient area and maturity of trees to
be called a “‘cedar swamp.” Here are found in addition Fraxinus
americana, Betula alba, Abies balsamea, and Acer rubrum. Around
the outer edges next the sand ridge, small specimens of Tsuga
canadensis are locally found.

In the cedar forests the shade is very heavy. The roots of the
trees interlace above the water or semiliquid muck, while the under-

1922] WATERMAN—PLANT COMMUNITIES 15

growth grows on the peaty soil which has collected in hummocks
or on the layer of tree roots. Shade-tolerant mosses are abundant,
and occasional restricted patches of sphagnum occur. Among
flowering plants the most common are Coptis trifolia, Cornus cana-
densis, Trientalis americana, Maianthemum canadense, Aralia nudi-
caulis,Gaultheria procumbens, Viola spp., and occasionally Clintonia
borealis. Aspidium spinulosum and Osmunda regalis are frequently
found, and some Taxus canadensis.

Fic. 7.—Algonquin shore, kept steep by erosion of Otter Creek

VEGETATION OF RIVER AND LAKE BORDERS.—In the Platte Plains
there are no true alluvial floodplains, and the shores of streams and
bodies of water are either rather steep sandy slopes, or else shallow
bays or lagoons inhabited by one of the types of communities already
described (figs. 6, 12).. The lakes are frequently shallow some dis-
tance from shore, and these shallows generally contain extensive
colonies of Scirpus. There is usually a fringe of aquatic plants,
including Typha latifolia, Sparganium, Sagittaria, Scirpus, etc., or of
shrubs including Myrica Gale and Decodon verticillatus. On flowing
Streams the latter does not seem to advance from year to year,
Probably on account of being torn away by ice in the spring. In

16 BOTANICAL GAZETTE [SEPTEMBER

this region Decodon is chiefly confined to streams, as it has been
observed on lakes or ponds in only one or two instances.

VEGETATION OF MORAINIC UPLANDS.—The morainic uplands
were covered with a typical climax beech-maple- hemlock forest,
which has been sufficiently described elsewhere (10, 12). In some
places this is almost untouched, and in at least two places, near
Lake Michigan on the west and south of Long and Rush Lakes,
the tension zone between it and the sand ridge vegetation is in prac-
tically its original condition. In the first locality this zone is about
a quarter of a mile wide, and its elements mingle with those of the
sand ridge formation. On the south it descends the steep Algon-
quin terrace to the shores of Long Lake, and merges with the cedar
forest between Long and Rush Lakes, and south and east of Platte
and Little Platte Lakes (fig. 7). North of Little Platte it originally
stopped on the crest of the steep bluff which borders the Otter
Creek valley, and the bluff was occupied by a xerophytic conifer
association, of which only a few patches now remain,

Development of communities

As already stated, the purpose of genetic synecology is to indi-
cate the successional relationships of the communities of a region,
and the place of each in a developmental series. In the present
study there is no rock substratum present, and only a very restricted
amount of clay or gravel, so that the communities found are largely
confined to the psammosere and the hydrosere. Secondary suc-
cessions are present, both in burned areas and to a limited degree
in clearings, but in the present paper the chief concern will be to
trace the stages of the original succession (prisere). With one or
two minor exceptions the influence of climatic and physiographic
factors is so slight as to be negligible, and the region is so young
geologically that there seems to be no necessity for the consideration
of paleoecological relationships.

SAND SUCCESSION (PSAMMOSERE)

PIONEER STAGES.—X erarch.—The pioneer stages of this succes-
sion are confined to the strip of shifting sand along the lake. The
initial vegetation includes Ammophila arenaria as the absolute

1922] WATERMAN—PLANT COMMUNITIES 17

pioneer, associated with Artemisia caudata, Calamovilfa longifolia,
Cirsium Pitcheri, Campanula rotundifolia, Cakile maritima, Lathyrus
maritima, Prunus pumila, Salix longifolia, S. syrticola, Senecio vul-
garis, Solidago spp., Aster sp., Zygadenus chlorantha, Hudsonia
tomentosa, Arctostaphylos uva-ursi, Juniperus communis, and J. hori-
zonialis. All of these are able to germinate on dune sand, but
only Ammophila is able to become established in pure sand. The
others are stunted and soon die, unless their roots come in contact
with buried plant material, from which apparently they are able
to obtain the necessary mineral elements. Ammophila and perhaps
Calamovilfa are the only plants which cover the ground _ thickly
enough to act as stabilizers. The other herbaceous plants are also
scattered, and never grow close enough to form a ground cover in
the moving dune belt. Arctostaphylos and Juniperus horizontalis
germinate occasionally on the open sand, but it is doubtful whether
they can stabilize. Whenever they occur in sufficient quantity to
cover the ground, it is usually by invasion from a patch already
established.

Hydrarch.—Juncus balticus and willows are the usual pioneers
in pannes. Occasionally a local patch of Pinus Banksiana, with
more or less Thuja occidentalis, Abies balsamea, and Betula alba, forms
a clump or grove, which may reach the size of several acres and
spread over small valleys or local patches of level sand. There is
no evidence of any extensive permanent stabilization by coniferous
trees in the belt of moving sand next to the lake. They frequently
occur as narrow strips or tongues between advancing lee slopes.
The transition from this area to the pine-oak ridges is very marked as
one crosses the irregular line of crescent-shaped lee slopes and comes
to the lower rounded ridges, where the force of the wind is much less
marked and the plants of the pine-oak stage have become estab-
lished. From this it would appear that the coniferous tree stage
originates in pannes, but does not really become widespread so as
to form a forest into which the more mesophytic pines and oaks
gradually migrate and become dominant, but that the coniferous
patches are relatively scattered, and their only influence is as
humus formers and as centers of distribution for certain elements
of the pine-oak stage. Stabilization, therefore, is due to a diminu-

18 BOTANICAL GAZETTE [SEPTEMBER

tion of the force of the wind, either on account of the increasing dis-
tance from the shore as the lake waters recede, or by the building
up by the wind of high dunes which form a windbreak and protect
the sand ridges.

PINE-OAK STAGE.—With the relative cessation of sand move-
ment, coupled with increase of humus, the pine-oak stages begin.
As might be expected, the content of vegetation on the ridges shows
a certain amount of progressive change, both in floristic content
and in the density of growth and mesophytism, as we traverse the

Fic. 8. iF of old pine, oak, and hemlock, probably protected by proximity
to Platte Rive

region from the vicinity of the lake toward the south (that is, from
younger to older ridges). On the first ridges there is a preponder-
ance of conifers and many relics of the herbaceous pioneers, especi-
ally Artemisia, Smilacina stellata, Arctostaphylos, and Juniperus
spp. The first tree of this stage to come into the coniferous asso-
ciation of the open dunes is Pinus Strobus, followed shortly by
P. resinosa. Quercus ellipsoidalis, Q. alba, and possibly Q. velutina
follow rather slowly, and now may be found fairly evenly distributed
in the more advanced portions of the area. Acer rubrum is very
frequently met near Platte River, or in other somewhat moist

1922] WATERMAN—PLANT COMMUNITIES 19

localities. Betula alba, Populus grandidentata, and P. tremuloides
are fairly common all through the region. As has been stated, the
region has been burned probably more than once, although for-
tunately not in recent years. The extent of area covered by any
one burning is uncertain. Certain local differences in distribution
can best be explained on the assumption that the burnings have
not been very complete; certainly some patches which bear old pines
and hemlocks must have escaped (fig. 8), but patches of white
birch and poplars indicate a secondary succession after fires.

-—Luxuriant growth of Pteris agquilina in mesophytic habitat, second
Aes hirch and poplar in background.

The undergrowth varies from the modified pioneer type of the
ridges nearest the lake to a mesophytic type containing many forms
belonging to the climax beech-maple-hemlock forest. These meso-
phytic associations are not distributed in accordance with the geo-
logic age of the ridges, but are determined rather by edaphic
conditions. They will be considered in the section on the beech-
maple-hemlock invasion. In addition to the typical mixed
ground cover already described, there are two types of undergrowth
societies unevenly distributed over the ridges, an almost pure
Pieris aquilina society and a Vaccinium society including V. penn-

20 BOTANICAL GAZETTE [SEPTEMBER

syluanicum, V. vacillans, with considerable Gaylussacia baccata.
On the whole, the Pferis communities are more characteristic of
the portion of the ridge area west of the Platte River and the
Vaccinium of that east of the river. No definite factors determining
the distribution of these communities have yet been established.
The Pleris seems to be more moisture-requiring than the Vaccinium,
and it certainly grows more luxuriantly in the moister habitats
(fig. 9). The Vaccinium species are usually regarded as more acid-
tolerant, and investigations along these lines may. yield definite
results. '
BEECH-MAPLE-HEMLOCK STAGE.—It is generally recognized
throughout Michigan that the deciduous hardwood forest is con-
fined to rich clay or loamy soil, white pine forests are found on
sandy loam, and the pioneer conifers on poor sandy soil. The
development of a climax deciduous forest on fixed dunes, as found
in the Point Betsie region and at other points along the Michigan
shore, is an interesting problem, the solution of which should
materially be aided by the evidence to be obtained from a study
of this relatively untouched region. As suggested by the preceding
morphological study, the climax forest which developed on the
morainic upland has begun to invade the sand ridge area along all
lines of contact between the moraines and the sand, the under-
growth having gone farthest, and the tree species migrating more
slowly. The first tree of the climax forest to appear in the sand
ridges is Tsuga canadensis, scattered specimens of which are found
up to a quarter or half a mile from the morainic border in the tension
zone on the west, and for varying distances on the other borders of
the sand ridge area. Many parts of the lowland border on the
south have been cleared of trees, but in the small triangle between
Long and Rush Lakes the deciduous forest is in contact with a
cedar swamp, and we can find there a horizontal succession in
practically untouched condition. The first hardwood pioneers in
the swamp are Fraxinus americana, F. nigra, Ulmus americana,
Tilia americana, and Acer rubrum. As Thuja disappears, the trees
of the beech-maple-hemlock forest begin to come in on an alluvial
substratum, forming a lake plain washed down from the Algonquin

1922] WATERMAN—PLANT COMMUNITIES 21

terrace on the south. The largest trees have been cut, but hemlock
stumps up to four feet in diameter are still to be seen.

On the strip of land between Long and Platte Lakes a scattered
and somewhat stunted growth of Tsuga canadensis, Acer saccharum,
and Fagus americana extends north almost to Michigan Highway
22, over soil which at first is somewhat alluvial, but which
gradually changes into the usual sand ridge type. Toward the
north the hard maples disappear first and the hemlocks last, as
the oaks and pines become more frequent. On the east very little
uniform advancement of the deciduous trees was found, probably
because of the steep xerophytic bluff occupied by conifers (fig. 7).
The valley of Otter Creek has not been studied in detail as yet, but
it seems to be largely occupied by conifers, although the soil condi-
tions are more those of an alluvial floodplain than in any other
part of the sand ridge region.

Apart from this rather uniform invasion along the borders,
there are several isolated spots where hemlocks at least are found in
some frequency and of considerable size. On the morainic ridge
between Platte and Little Platte Lakes the deciduous forest was
apparently well developed, with, however, a large proportion of
pines and some oaks. Large hemlocks are found in several places
along the east bank of Platte River north of Platte Lake (fig. 8), and
in the valley on the south slope of the morainic fragment on the shore
of Lake Michigan (fig. 10). In the last locality they are in poor con-
dition, and some have recently died. Small specimens are to be found
on the edges of many of the smaller swamp depressions, especially
on the southwest of Loon Lake, that is, on the opposite side of
Platte River from the morainic ridge extension just mentioned.
Fagus americana has not been found away from the borders and
the wedge-shaped invasion between Platte and Little Platte Lakes.
A solitary specimen apparently about fifty years of age is growing
by Michigan Highway 22, about a quarter of a mile west of
Platte River, and therefore in the heart of the sand ridge area. Its
Shape shows that it grew in the open, but its age does not preclude
the possibility of its having been planted by the first settlers. The
mixed coniferous-deciduous lake bluff border association described

pe BOTANICAL GAZETTE [SEPTEMBER

in the Crystal Lake Bar region (10) does not appear in this region,
probably because the corresponding habitat is not present. This
association contained Thuja occidentalis, Abies balsamea, Tilia
americana, and Osirya virginiana, mixed with the trees of the climax
deciduous forest on the crest of the bluffs facing Lake Michigan. It
was apparently due to the exposure to sun and lake winds, combined
with low soil moisture content. The only place where it might
have been expected was on the high bank at the eastern edge of the

o.—Morainic remnant on shore of Lake Michigan; laridward slope equally
ed ‘wid hemlocks growing in valley.

sand ridge region, and there the only conifers seem to have been
Pinus Strobus and P. resinosa.

The preceding discussion indicates that the migration of the
beech-maple-hemlock forest into the sand ridge formation has been
of two sorts, one a general advance along all lines of contact
between the two formations, the other in a long slender belt on
the morainic ridge and its remains, to the shore of Lake Michigan
(fig. 10). Unpublished investigations by the writer indicate that for
the establishment of Thuja occidentalis and Abies balsamea on sandy
soil it is necessary that there should be present in the sand enough
moisture to carry the young tree root below the drought zone. This

1922] WATERMAN—PLANT COMMUNITIES : 23

may be held by humus in the soil, or by a high moisture content in
sand relatively free from humus, and it seeems possible that this
may also be true for Tsuga, but not for Fagus. Acer saccharum
seemed to hold an intermediate position between the two, and its
apparent absence from any advanced positions on the sand ridge
habitat was a distinct surprise. Morainic soil equally with humus
seems to afford a suitable substratum for the establishment of all
the species mentioned, either because of the supply of necessary
mineral elements, or because these minerals make possible a better
utilization of the water present. For these reasons the advance-
ment of the deciduous formation seems to be the result of increased
humus content and mesophytism, and also a pushing forward by
sheer force of numbers. The parent seed trees being so near at
hand and supplying so many seeds, it follows that in time a fair
number of seedlings have been able to find conditions favorable to
growth and so become established. In the other case, the morainic
substratum affords a soil peculiarly favorable to the deciduous trees,
and while a much smaller number of seeds have lodged on it, a
relatively larger proportion have become established. In view of
the fact that the shade and moisture conditions vary greatly
on different parts of this ridge, it would seem to be the chemical
constituents of the soil which give to it its favorable character-
istics.

The question may be raised as to whether this condition may
not be the result of the prehistoric fires, previous to which the
beech-maple-hemlock elements may have been more widely dis-
tributed, and the present isolated groups may be relics preserved
because of the protection of bodies of water. Against this view may
be set the evidence of tradition and the entire absence of stumps in
other moist habitats of the region which seem to have been un-
touched by fires. Unquestionably even hemlock stumps and logs
do not last as long as pine, but it might be expected that some traces
would remain if they had been at all widespread in comparatively
recent times. This, however, would not account for the appearance
of hemlocks on the edges of swamps at some distance from these
telic patches. It is also reasonable to suppose that reforestation
after a fire would proceed along general lines similar to those of

24 BOTANICAL GAZETTE [SEPTEMBER

the original advance, so that in either event the stages of the prisere
would be approximately as outlined.

AQUATIC SUCCESSION (HYDROSERE)

The substratum in this succession is standing water, either in
closed depressions such as ponds and small lakes, or in open depres-
sions as bays or lagoons along the banks of lakes or of Platte River.
These various bodies of water show practically the same vegetation
for the first three stages, commonly designated as the Pota-
mogeton, Nymphaea, and Scirpus stages. After that different lines
of succession are found, depending on the condition of the habitat.

SAND RIDGE DEPRESSIONS CONTAINING STANDING WATER.—In
these depressions the water is fairly shallow, but the depression is
surrounded by sand ridges whose slopes rise directly from the
water’s edge. Here are to be found either swamp or bog stages
according to the condition of the substratum. In the swamp type
the fourth stage is a narrow sedge zone, the shrub growth is scanty,
mostly willows, and the sand ridge vegetation descends the slopes
almost to the water’s edge. In the bog type the quaking mat is
seldom found, but there is a dense growth of sedges and grasses on a
fairly solid muck foundation. This contains such bog plants as
Menyanthes trifoliata, Potentilla palustris, and occasionally Sar-
racenia purpurea, and Sphagnum sp. The shrub zone is a dense
thicket of Alnus incana, Pyrus arbutifolia, with some Hamamelis
virginiana, and sometimes with scattered specimens of Thuja
occidentalis and even Tsuga canadensis mingling with poplars and
the first trees of the pine-oak association. The water is frequently
shallow on the north side of the pond, possibly from sand blown in
by the winds from Lake Michigan, and of course is exposed to the
heat of the sun, but protected from the colder winds. The south
side has deeper water, and is more sheltered from the heat of the
sun on account of the shade of the pines and oaks, but exposed
to the cold winds. In depressions of this kind the swamp vegetation
is found on the shallow, warmer, northern side, while the bog type
occurs on the deeper, cooler, southern side. In depressions which
are sheltered on all sides and in which the water is deep all over, the
bog type generally prevails over the whole pond.

1922] WATERMAN—PLANT COMMUNITIES 25

GRASS MEADOW TYPE.—Here the fourth stage is one dominated
by grasses and sedges forming a relatively solid turf. In the small-
est depressions the sedge society may be only a few yards square,
and in it there are often found swamp plants such as Hypericum
virginicum, Spiraea salicifolia, and Rosa carolina, as well as occa-
sional relics of the aquatic stages. The later stages resemble those
of the swamp type already described. The larger grass meadows
are relatively limited in number, only four or five having been dis-
covered so far, and they have certain peculiar features which seem
to demand special consideration. The first is the mature condition
of the extensive grass turf, and the other is the absence of any
tendency of the shrubs and trees to invade the meadow. Where
the grass meadow is surrounded by a shrub zone of the swamp type,
this may be accounted for on the assumption that the depression
was originally all very shallow, thus favoring a development of turf
so rapid that the shrubs and trees had no chance to become estab-
lished before the mat of grass roots had completely occupied the
substratum. There are, however, some features which indicate
that the grass mat was formed recently and very rapidly, indicating
perhaps a physiographic change in comparatively recent times.
These are best shown in a grass meadow visited only once, as it was
discovered in a hurried reconnoissance trip, and so far there has
been no opportunity for a second visit. This meadow is located
just west of the lower reaches of the Platte River very near the
strip of moving dunes on the shore. It extends from northeast to
southwest practically in a straight line for rather more than half a
mile, but is less than a hundred yards wide at the point crossed,
although somewhat wider to the east and the west. At this point
there were imbedded in the grass on both edges of the meadow
trunks of dead trees extending out from both banks, and on each
tree was growing a row of tamaracks apparently not over twenty-
five years old. There were scattered tamarack trees on the lower
edges of the sand ridges. While the localization of the tamaracks
on the dead logs and not in the grass is not surprising, the preserva-
tion of the logs long enough for the grass turf to form and the
apparent youth of the trees makes a very interesting problem.
This meadow apparently has never been mowed or burned. The

26 BOTANICAL GAZETTE [SEPTEMBER

logs may have come from trees killed by prehistoric fires, as they
had no bark on them, but they were not charred, and otherwise
seemed well preserved, with many dead branches extending up
among the young tamarack trees. In fact, the whole situation
suggested the sudden freezing of the surface of a pond, solidifying
into a green grass mat, instead of a covering of ice. In the case of
the large meadow occupying a shallow swale between Long and
Rush Lakes, which at one time might have been a water connection
between the two lakes, the shore showed the regular horizontal

G. 11.—Grass oo near Long Lake; bog shrubs on left, with tamaracks and
cedar ant behind the

stages of a bog-cedar forest succession, but the center of the swale
is occupied by a meadow with solid turf (fig. 11). The meadow
has been mowed for years, and was recently ditched for draining,
but this treatment apparently has not changed the general
relations. The shrub zone at its southern edge is the usual bog
shrub stage, followed by a belt of tamaracks of considerable size.
A mature cedar forest adjoins this on the south, with a fairly dry
substratum and some of the undergrowth elements of the deciduous
forest. Next come deciduous swamp trees, and finally the trees of
the climax forest. Here we have a bog forest left high and relatively
dry, with a grass meadow formed at its edge.

922] WATERMAN—PLANT COMMUNITIES 27

Each of these formations, although differently situated (one
in the heart of the sand ridges, the other between two lakes), seems
to indicate the same physiographic change, that is, a sudden lower-
ing of the water table by several feet. This change might be
referred to the activities of the first white settlers about fifty years
ago. The Long Lake area is very close to Crystal Lake, and might
have been partially drained by seepage when Crystal Lake level
was lowered in 1871 (10). A low terrace on the south bank of Long
Lake adds weight to this hypothesis. The other meadow must
have come very close to Platte River at its eastern extremity, and
may have been lowered in connection with the first lumbering opera-
tions at about the same time. :

Another explanation of the lowering of the water is based on
diastrophic changes. Observations on the shore of Lake Michigan,
both on the Michigan side and on the Green Bay Peninsula opposite,
indicate that fifty years ago the lake was several feet higher than
the highest levels of recent years, and this fall of level might have
affected the level of Platte River in its lower reaches (fig. 12).
There are also extensive meadows bordering Platte River and the
sluggish stream connecting Platte and Little Platte Lakes, whose
origin may be connected with the lowering of water levels at
about the same time. Further study, both of the floristic content
and of the nature of the substratum, is necessary before definite
conclusions can be reached. There is no indication of any migra-
tion of trees into a grass meadow with solid grass mat, whether
large or small, but there seems to be some evidence that they can
come in on a floating mat of the swamp type. . Further investigation
may show that the latter case is really a bog mat, in which event
it would not be available as evidence, and the presence of trees
would be quite in accordance with the rule for bog mats.

Boc typr.—Here the fourth stage develops as a bog mat com-
posed of sphagnum and the usual accompanying bog plants. In
several cases this has developed into an ericad heath composed
largely of Chamaedaphne, Andromeda, occasionally Ledum and
similar shrubs, including Betula pumila, and scattered trees of
Larix, Picea mariana, and occasionally Pinus Strobus and P. resi-
nosa. In other cases the tamaracks with some bog shrubs and

28 BOTANICAL GAZETTE [SEPTEMBER

Thuja have come in very thickly, forming a bog thicket which in
some cases apparently may develop into a cedar forest. The
tamaracks in this region are all small, with the exception of those
between the shrub belt and the cedar forest already noted between
Long and Platte Lakes. The occurrence of bog vegetation in the
depressions among sand ridges has already been noted. The varia-
tion in depth on opposite sides also applies to some extent to the
larger ponds and lakes. In the latter cases the shallow portions
are characterized by extensive Scirpus colonies, but the bog asso-

2.—Lower reaches of Platte River, bordered by grass meadows, with some
eel; growth birches; sand ridges in distance.

ciations do not appear along the shores of the lakes. In open
bays and lagoons there was no general uniformity, but swamp
or bog types were found corresponding to the varying local condi-
tions. From this it is concluded that the development of the later
stages of the hydrosere into the swamp or the bog type is dependent
chiefly on depth of water and temperature. Investigations as to
acidity have not been made as yet, but it is assumed that here, as
elsewhere, the swamp type will be associated with a neutral or
alkaline condition and the bog type with high acidity. The tree
stage in the hydrosere was found to follow only the quaking mat

1922] WATERMAN—PLANT COMMUNITIES 29

stage, and not the grass meadow. If we accept the hypothesis for
the very recent formation of the large grass meadows, the absence
of trees might be attributed to shortness of time, but the same
condition is found in the smallest meadows, which from their posi-
tion and general appearance must be regarded as contemporaneous
with the wet depressions and with the sand ridges themselves, and
here there should have been ample time for invasion. It does not
follow necessarily that the grass meadow is an edaphic climax, but
it is evident that that association will remain stable for a very long
time. As already noted, the bog mat passes relatively rapidly into
a tamarack cedar forest, which quickly receives hydrophytic decidu-
ous elements, and thus passes into the climax deciduous forest.

Summary

1. Genetic synecology is that part of ecology which deals with
the developmental relations of plant communities. In a limited
region the development of successions (seres) is definitely related
to the character of the substratum. In this region two such seres
are found, the sand succession (psammosere) and the aquatic
succession (hydrosere). The clay-gravel succession (geosere) has
reached its climax on the surrounding moraines, and is observed
only as it invades the sand ridge region.

2. In this study the successional units, the concrete association
and formation, are defined as follows. The association is a plant
community of essentially uniform (or homogeneous) physiognomy
and ecological structure, and of essentially uniform (or homo-
geneous) floristic composition as regards dominant species. The
formation is an association-complex characterized by a dominant
association, but including all adjacent associations, whether mature
or immature, and other more or less anomalous or unidentified com-
munities associated with them. The unit above the formation is a
formation complex, or aggregate, and is composed of the formations
of a definite region which may be limited by climatic or geographic
boundaries. The ground occupied by an association is called a
locality, that occupied by a formation an area, and that occupied by
a formation complex a region.

3. The vegetation of the region studied is found to be a forma-
tion complex consisting of a sand dune formation, a sand ridge

30 BOTANICAL GAZETTE [SEPTEMBER

formation, and swamp and bog formations. It occupies a region
which consists of sand ridges with depressions containing bodies
of water of all sizes, from a few yards to a mile or more in diameter.
Geologically the region was a shallow bay of Lake Algonquin
drained by the recession of the waters of the lake with the melting
of the ice barrier in the Straits of Mackinaw.

4. The first stages of the sand succession (psammosere) are
found in the moving dune belt along the shore, but they do not
lead to a complete stabilization of the sand. The later stages
appear when the sand stops moving as a result of a checking of the
force of the wind, due to distance from the shore or the formation
of high dunes which act as windbreaks. The pine-oak stage shows
a progressive change from the less mature areas near the lake to
the more mesophytic areas in the southern portion of the region.
Soil moisture content and the amount of humus in the sand seem
to be important factors in this change.

5. The clay-gravel succession (geosere) has reached the climax
stage as a beech-maple-hemlock forest on the surrounding morainic
upland, and is found invading the pine-oak formation along the
borders of the region, and especially along a narrow morainic tongue
which extends completely through the sand ridge substratum to
Lake Michigan. The controlling factor in this invasion seems to be
primarily the chemical character of the soil, glacial material ranking
close to humus in importance, and secondarily the soil moisture
content.

6. The various ponds and lakes all show the normal early stages
of the aquatic succession (hydrosere), which lead either to swamp
meadows or to bog forests, the line of development followed being
determined chiefly by depth of water and exposure to the heat of
the sun.

NORTHWESTERN UNIVERSITY
Evanston, Ibi.

LITERATURE CITED
. CLemeEntTs, F. E., Plant succession. Carnegie Publ. no. 242. 1916.
. Cooper, W. S., The climax forest of Isle Royale, Lake Superior, and its
development. Bort. Gaz. 55:1-44. 1913.

1922] WATERMAN—PLANT COMMUNITIES 31

gop

—

Cowtes, H. C., The physiographic ecology of Chicago and vicinity, a
study of the origin, development, and classification of plant societies.
Bot. GAz. 31:73-108; 145-182. 190

, The causes of vegetative ao. Bor. GAz. 51:161~183. 1911.

- Moss, C. E., Geographical distribution of vegetation in Somerset. Royal

Geog. Soc. 1907.

. Nicuots, G. E., The interpretation and application of certain terms and

concepts in the ecological classification of plant communities. Plant
World 20: 305-319; 341-353. 1917.

, Abstract in printed program of Ecological Society of America for
Meeting at Toronto, December, 1921

- TANSLEY, A. G., Types of British vegetation, Cambridge

ge. Igit.
, The cliaitiiestion of Pgeaare and the concept of aovcksceien.
Jour. Ecology 8: 118-149. 19
WATERMAN, W. G., Sostnae of Crystal Lake Bar region. Ann. Report
Mich. Acad. Sci. 19:197-208. 1917.
, Development of root systems under dune conditions. Bor. Gaz.
68 :40-63, 1919.

- Wurrrorp, H. N., The genetic development of the forests - Northern

Michigan. Bor. Gaz. 31: 289-325. Igor.

SULPHUR CONTENT OF SOILS AND ITS RELATION TO
PLANT NUTRITION
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 297
Scott V. EATON
( ITH ONE FIGURE)
Introduction

Ever since the ten essential elements for plant nutrition were
established by the work of Sacus, BousstncAuLt, Nopse, and
other investigators, sulphur has been recognized as one of them.
The ash analysis method of determining sulphur in plants, however,
which was in use during this early period, showed such a small
amount present that the needs of the plant were thought to be
amply taken care of by the supply in the soil. Contributions
during the last twenty years by BERTHELOT, BARLOW, FRAPS,
Goss, BESTLE, SHERMAN, and others have shown that in ashing
plant material much of the sulphur may be lost. The amount
of sulphur in plants as determined by analyzing the ash may be
only a fraction of the real amount. Thus the whole question of
the relation of sulphur to plant nutrition has been reopened,
for if plants use several times as much sulphur as had been sup-
posed, then perhaps the supply in the soil is not sufficient for
the needs of the plant. Recently there have been a number of
contributions to the subject. The first questions to be considered
have naturally been how much sulphur do crops use and what are
the supplies to meet these needs. Thus the first problems to be
investigated have been the sulphur content of crops, the sulphur
content of soils, the amount of sulphur brought down by the rain,
and the amount lost by drainage, etc. Next, sulphur was added
to soils found to be low in it to see whether the yield of crops would
be increased. In the present paper no attempt is made even to
approximate a resumé of the sulphur literature, rather complete
digests of which may be found in papers by CrockER (4) and
OLSON (19).
Botanical Gazette, vol. 74] [32

eee

1922] EATON—SULPHUR CONTENT OF SOILS 33

ROBINSON and co-workers (22, 23) have analyzed a number of
soils from different parts of the United States. The sulphur
content is not high, the average for thirty-five important agri-
cultural soils being 0.052 per cent, with a range of 0.012-0.156
per cent. SHEDD (24) finds the soils of Kentucky much poorer
in sulphur than in phosphorus, and is inclined to place sulphur
in the same class with phosphorus, potassium, and nitrogen as
one of the chief limiting factors in crop production. In pot
experiments with some of these soils, tobacco, soy beans, turnips,
radishes, mustard, and alfalfa were benefited by sulphur fertiliza-
tion. Ames and Bortz (1) report analyses for certain Ohio soils.
The unfertilized soils range in sulphur content from 0.020 to as
high as 0.055 per cent. Brown and Kettoce (2) find nearly
twice as much sulphur as phosphorus in some of the larger soil areas
of Iowa. The Mississippi loess proves to be lowest, the soil samples
in this area ranging in sulphur content from 441 to 847 pounds
per two million pounds of soil. Swanson and MILLER (27) have
analyzed a number of the soils of Kansas and find that the culti-
vated soils analyzed have an average sulphur content of 0.027
per cent. Certain cultivated soils of Wisconsin, analyzed by
Hart and Peterson (8), prove to be low in sulphur, the average
being 0.020 per cent. They summarize the results of their analyses
of a number of crops by stating that cereal crops remove from the
soil about two-thirds as much sulphur trioxide as phosphorus pen-
toxide, the grasses of mixed hay as much sulphur as phosphorus,
while the legume hays may take from the soil about as much sulphur
as phosphorus, or, as in the case of alfalfa, more sulphur than
Phosphorus. Such crops as the cabbage and the turnip may
remove two to three times as much sulphur trioxide as phosphorus
pentoxide. RerMeR and Tartar (21) give analyses for a number
of Oregon soils. The range in the sulphur content of the surface
Soils is o.015-0.038 per cent. The phosphorus content is much
greater. The sulphur fertilization of alfalfa grown on these soils
Produces greatly increased yields. Increased tonnage yields of
50-1000 per cent are secured, and the protein content is increased
in some cases almost 2 percent. In experiments in Washington by

34 BOTANICAL GAZETTE [SEPTEMBER

OLSON (19), sulphur fertilization of alfalfa caused increased yields
of 200-300 per cent.

The purpose of the present investigation was (1) to increase our
knowledge of the sulphur content of soils, and (2) to study the
relation of sulphur to chlorophyll development in certain plants
and its effect on the yield of these plants. The phosphorus content
of all the soils was also determined. Phosphorus, together with
nitrogen, is considered the most generally limiting element of crop
production in the soils of the United States. It was thought that
it would be interesting to compare the sulphur content of the soils
with their content of such an element as phosphorus. |

Investigation
SOIL ANALYSIS

It is important for American agriculture to discover how many
soils in the United States are suffering from lack of sulphur, as are
the Oregon soils to which reference has already been made.. The
Oregon results might be duplicated, perhaps, in the case of many
other soils; on the other hand, many soils are probably not lacking
in sulphur. The samples were chosen with a view of giving some
idea of what range in sulphur content might be expected in the
soils of the eastern and central United States. Thus, samples
from the Atlantic and Gulf coast regions, from one of the southern
states, from certain of the north central states, and from Chicago
were analyzed. Investigations on the Atlantic coast during the
early history of the United States showed great benefits from the
use of gypsum as a fertilizer. It was thought that the analysis of
certain of the coast soils might give some interesting results. On
the other hand, soil analyses and sulphur fertilization tests in
the central states may be said to indicate, in general, a higher sul-
phur content in the soils of this section than in the coast soils.
It was desired to analyze a number of soils of the central states to
compare with the coast soils. It is well known that rain carries
down much more sulphur from a smoky atmosphere than from
one less contaminated with smoke. It was thought that the
Chicago soils might prove to have a very high sulphur content,
owing to this fact.

1922] EATON—SULPHUR CONTENT OF SOILS 35

Methods

Three methods of total sulphur determination were tested, the
sodium peroxide method as evolved by Hart and Peterson (8), the
VAN BEMMELEN method as modified by the same investigators, and
a sodium carbonate fusion method, which was really a combination
of Kocn’s (12) sodium carbonate method for the determination of
total sulphur in organic material and HILLEBRAND’s (10) sodium
carbonate method for the determination of total sulphur in rocks.
The sodium peroxide method gave as high results as the other
methods and better duplicates, and also was easier to manipulate.
It was therefore adopted, but modified somewhat, and so it is
given in some detail.

Ten grams of soil was placed in a roo cc. nickel crucible, made
quite moist with water, and 1o gm. of sodium peroxide added,
a little at a time, stirring thoroughly with a nickel rod as the
sodium peroxide was being added. This was heated slowly with
a microburner until dry, and 10 gm. more of sodium peroxide
added, spreading it over the surface, and continuing the heating
until the surface layer melted. With a blast burner the mass
was then brought to red heat and kept in this condition for ten
minutes, stirring thoroughly. This was allowed to stand over a
moderate flame for one hour, cooled, and the fused mass removed
with boiling water, transferring it to a 600 cc. beaker. This was
neutralized with concentrated HCl and then 10 cc. excess added,
and allowed to stand on the steam bath for five or six hours, or
until there was no undecomposed material in the bottom. It
was next transferred to a 5oocc. volumetric flask, cooled, filled
to the mark, and allowed to stand for four or five hours, shaking
at intervals. A 250 cc. aliquot was filtered off, transferred to a
beaker, a quantity of filter paper pulp added, and while stirring
the iron, aluminum, etc., was precipitated out with ammonium
hydroxide. This was heated for an hour on the steam bath,
filtered into an 800 cc. beaker, and the precipitate washed with
hot water until 600 cc. was obtained. After this it was heated to
boiling, to cc. of hot 10 per cent barium chloride added to the
boiling solution, and allowed to stand on the steam bath over
night and at room temperature for the remainder of the twenty-

36 BOTANICAL GAZETTE [SEPTEMBER

four hours. The volume must not be allowed to decrease while on
the steam bath. The solution was then filtered off from the
barium sulphate, washed until no test for chlorides was obtained,
the precipitate dried in an oven, and ignited to constant weight in a
muffle furnace.

Part of the sulphur determinations reported later in this paper
were obtained by igniting over a microburner, taking care that the
paper was consumed without flaming up, but it was found that
more uniformly successful results were obtained by igniting in a
muffle furnace.

The iron and aluminum were removed because it was found
that, in the case of a number of the soils analyzed, the barium
sulphate precipitate was quite seriously contaminated by the iron.
In the case of some of the soils analyzed during the preliminary
work, the iron collected in masses on the bottom of the beaker.
In other cases there was no contamination, or so little that the
error introduced was small. It was decided, however, to make it
a general practice to remove the iron and aluminum before adding
the barium chloride solution. The chief difficulty encountered
in the process was in washing out the sulphate ion from the iron
and aluminum hydroxides. By using hot water, however, and
having the precipitate well separated with paper pulp, the sulphate
ion was completely washed out. It was found that there was some
sulphur in the reagents used. Blanks were run and correction
made for this.

The phosphorus was determined by the magnesium nitrate
method as given in the Methods of Analysis of the Association of
Official Agricultural Chemists (17). No important modification
was made in the method. The ignition value given is the loss
in weight obtained by heating the soil in the muffle furnace at
red heat for an hour and a half. Two or three grams were used,
and it was found that after heating for this length of time there
was no loss of weight on further heating.

Data

In the following results of the analyses, the samples that proved
to have the lowest sulphur content will be given first. The chief

1922] EATON—SULPHUR CONTENT OF SOILS 37

lack in the data is information as to the previous history of the
soils from which the samples were taken. In a number of instances
I have data as to the productivity of the soils, and information as
to the amount of manure and fertilizer that had been applied to
the soils in recent years, but in some cases it was impossible to
secure this information. Also, the data would have more general
significance, perhaps, if in all cases the names of the soil types could

Per Cent

L | i i
Alabama Maryland Oklahoma Central States Chicago

Fic. 1.—Curve comparing sulphur, phosphorus, and organic matter content of
five groups of soils ; organic matter divided by 200.

be given, but this was only possible for the Maryland soils. In
most instances, however, the samples were taken from important
agricultural soils, and therefore the data should have significance
i adding to the information as to the sulphur content of the
agricultural soils of different sections of the United States. All
the results are figured on the basis of the oven-dry weight. The
data concerning the pounds of sulphur per acre were obtained from
the percentage of sulphur determined by analysis, by assuming
that an acre of soil 6. 5-7 inches in depth weighs 2,000,000 pounds.

38 BOTANICAL GAZETTE [SEPTEMBER

Tables I and II give the results of the analysis of some soil
samples from the Gulf coast and the Atlantic coast. I am in-
debted to Dr. A. G. McCa tt, of the University of Maryland, for the
Maryland samples, and also for the information in regard to the
productivity of the soils. Little information was obtainable in
regard to the samples of table I, except that they came from soils

TABLE I

SULPHUR, PHOSPHORUS, AND ORGANIC MATTER CONTENT OF CERTAIN ALABAMA SOILS
NEAR MosILe BAy), TAKEN FROM SURFACE

Sample no peng Lb. per acre ce Lb. per acre Ignition value
Peo ay 180 0.0028 56 2.189
16 Us 0.0148 296 0.0044 88 7.327
Fie os 0.0151 302 0.0067 134 2.256
Loe es 0.0126 252 0.0044 2.204
Average. .. 0.0128 256 0.0045 90 2.194

TABLE II

SULPHUR, PHOSPHORUS, AND ORGANIC MATTER CONTENT OF CERTAIN MARYLAND SOILS

OR as Worcester 7 0.028 560 0.015 300 2.48
A Cr orcester 7-28 0.023 A008 Se aa ae 1. 36
ae oa Talbot O-7 0.023 460 0.026 520 4.39
a6. . Talbot 7-28 0.015 300 0.012 240 4.71
ps gee es ne St. Mary’s 7 0.018 360 0.026 520 4.66
bc S. St. Mary’s 7-28 0,020 400 0.018 360 4.54
ot eae Sap Howa 7 0.019 380 0.048 960 6.33
SOs fc Howard 7-28 0.014 280 ° 880 6.14
Coe ee Prince George | 0-7 0.030 600 0.030 600 4.81
$2.50 se: Prince George | 7-28 0.019 380 0.026 520 4:91
Average surface soils............ 0.023 460 0.029 580 4.53
Average subsoils........ pO ae 0.018 360 0.025 500 4-37

on which the attempt was being made to grow pecans. The
soils are so low in sulphur, phosphorus, and organic matter that
it would seem impossible to grow any crop successfully on them
without considerable fertilizing.

Samples 23 and 24 of table II belong to the soil type known as
Norfolk fine sandy loam. The field from which the samples were
taken is fairly productive, being capable of producing ten bushels

1922] EATON—SULPHUR CONTENT OF SOILS 39

of wheat or thirty bushels of corn per acre. The samples from
Talbot County belong to the Elkton silt loam type of soil. It is
not very productive, and has to be fertilized rather heavily to
produce very good crops. The soil represented by samples 27 and
28 is known as the Leonardtown silt loam type of soil. It has
rather low productivity, producing about 500 pounds of tobacco or
seven bushels of wheat per acre. The samples from Howard
County belong to the Chester loam soil type, which is one of the
best soils in the state, producing sixty-five bushels of corn or twenty
bushels of wheat per acre. Samples 31 and 32 belong to the
sassafras silt loam type. This is a fairly good soil, producing ten
bushels of wheat or thirty-five bushels of corn per acre. The
samples from St. Mary’s County and from Howard County are
from soils that had not been fertilized in recent years. The
other soils have probably received recently little if any fertilizers.
The Maryland samples are rather few in number, but are well
distributed over the state. They are probably typical for the
cultivated soils of Maryland. The soils are low in sulphur, phos-
phorus, and organic matter; somewhat lower in sulphur on the
average than in phosphorus. It would seem that they should be
benefited by the use of both sulphur and phosphorus as fertilizers.

Table III is an attempt to make a further study of the Mary-
land soils, using as a basis the productivity data and the data for
the surface soils of table II. The second column shows the relative
order of the five soils in productivity, beginning with the most
productive. There does not seem to be any relation between the
sulphur content and the productivity. When we consider the
phosphorus content, however, the two best soils as to productivity
are also highest in phosphorus. This relation between phosphorus
content and productivity does not hold in the case of the other
three soils, but here the phosphorus content is so low that other
factors may be limiting production. It would seem possible,
therefore, especially in the case of the fields from which the Chester
loam and sassafras silt loam samples came, that phosphorus rather
than sulphur was limiting production. The Chester loam soil
especially should be considered. It is one of the best soils of the
state and in its phosphorus content also it is decidedly higher than

40 BOTANICAL GAZETTE [SEPTE MBER

any other of the soils analyzed. The order of the soils as to the
organic matter content is about the same as their order considered
on the basis of the phosphorus content. It might be that the
relatively large amount of organic matter in the Chester loam
and the sassafras silt loam soils is a factor in their productivity.
Organic matter improves the tilth of soils, adds plant food, and
has other important effects.

Their relative ability to produce cereal crops is used as a meas-
ure of the productivity of the soils. Cereal crops require more
phosphorus than sulphur. It might well be that, if the production
of a high sulphur containing crop (alfalfa, for instance) was taken
as the criterion, the order of the soils in table III would be different.
Even if phosphorus, rather than sulphur, is at present the limiting

TABLE U1

RELATIVE ORDER OF THE FIVE MARYLAND SOILS IN PRODUCTIVITY, SULPHUR,
PHOSPHORUS, AND IGNITION VALUE

Soil type Productivity Sulphur Phosphorus |Ignition value

i=J

5
ne WN
WwW Nn
WWwudb H
wud H

factor in these soils, sulphur would no doubt soon become the
limiting factor if the level of supply of the phosphorus is raised by
adding phosphorus fertilizers. The sulphur supply is so low that,
with phosphorus removed as the limiting factor, it might become
the limiting factor to production.

Of course it is realized that too great reliance should not be
placed in a soil analysis, especially such a soil analysis as this,
where only two of the several elements needed by plants are
determined. At the most, a soil analysis only shows the total
amount of plant food present and does not tell anything as to the
availability of the elements. Also, other factors than plant food
may be limiting production, but a soil analysis should develop
some leads, which can be followed up by other methods of attack.

Since the data show a rather low sulphur content in the few
Atlantic coast and Gulf coast soils analyzed, it might be of interest

——

1922] EATON—SULPHUR CONTENT OF SOILS 41

to see what results have been obtained from using sulphur as a
fertilizer in these regions. Very little work of this kind has been
done. Several stations report a favorable effect from using phos-
phorus or potassium as a fertilizer for alfalfa, when the carrier of
the phosphorus or potassium also contained sulphur. The Dela-
ware station (7), for example, reports greatly increased yields of
alfalfa due to acid phosphate. Experiments in Oregon (21) have
shown a decided increase from applying acid phosphate to soils,
but no increase due to phosphorus in any other form. Here it has
been definitely proved that the increased yield caused by acid
phosphate was due to the sulphur of the acid phosphate, and not
to the phosphorus. It would seem worth while to test this in the
case of the Delaware soils. The Virginia station (3) secures
increased yields of alfalfa due to phosphorus in the form of acid
phosphate and basic slag, but not in the case of other forms of
phosphorus, such as rock phosphate. Here again we have the
possibility that sulphur is responsible for the increased yields.
The Massachusetts station (16) finds sulphate of potash a better
fertilizer for alfalfa than muriate of potash. The alfalfa of the
sulphate of potash plats was also a darker green. Clearly these
results are due to the sulphur present in the sulphate of potash, and
not to any differences in the potassium.

The best experiments on the Atlantic coast to show the effect
of sulphur fertilization on crops are those of the investigators of the
colonial period, whose work is summarized by CROCKER (4).
PETERS and Binns were the most prominent of these investigators.
They performed numerous experiments showing the effect of
Sypsum on crop yield. Leguminous crops especially were benefited,
red clover giving increased yields of two to threefold. Binns
Teported like increased yields for corn and wheat. Although the
Teports of the experiments do not make this clear, it seems likely
that the beneficial effects of gypsum on the non-leguminous crops -
was due to the increased nitrogen supply brought about by the
Sreater growth of the legumes of the rotation. RUFFIN was also
greatly impressed by the results obtained from the use of gypsum
as a fertilizer. In his Essay on calcareous manures he speaks of the
magic effects obtained from applying gypsum as a fertilizer to

42 BOTANICAL GAZETTE [SEPTEMBER

clover. Considering the results of the writer’s analyses, together
with the other experimental work to which reference has been
made, it would seem worth while to test sulphur as a fertilizer
throughout the Atlantic coast region.

_The samples of table IV were taken in cultivated fields near
Miami, Oklahoma, two of the samples from one field and two from
another. Nothing is known as to the previous treatment of the soils
from which the samples came, or it might be possible to answer
some questions which arise from a study of the data, such as the
reason for the much greater phosphorus content of samples 21
and 22 than of samples 19 and 20.

TABLE IV

SULPHUR, PHOSPHORUS, AND ORGANIC MATTER CONTENT OF CERTAIN SOILS NEAR
Miami, OKLAHOMA

Sample Depth got ang Lb. per acre ft Ri . Lb. per acre |Ignition value
1 Surface 0.0202 404 0.0107 ‘274 4.340
On od Subsoil 0.0287 574 0.008 I 7.764
Py geen a ae Surface 0.0278 556 0.0587 1174 6.710
BOP a, Subsoil 0.0136 272 0.0543 1086 5.290

Average surface soil...| 0.0240 480 0.0347 604 5.528

Pets subsoils ...... 0.0211 422 0.0315 630 6.527

aan ai s not certain that subsoil 20 cond 22 go > with hol 2 19 aude 2r ‘teapunthvals: “ek were aang

Table V contains the results of the analyses of certain soils
of the central states. Samples 3 and 4 were taken in an alfalfa
field; samples 5 and 6 in an oat field. The alfalfa field had been
manured with one and one-half tons of cow manure per acre in
1918. ‘The oat field had received in the same year an application of
two tons per acre of cow manure. Both fields had been fertilized
with gypsum in 1920. Samples 7, 8, 9, and ro were all taken in
one field of seven acres, which had been in grass for many years.
This field was put in corn in 1920, producing only a fair crop. In
the fall of 1920 it was put in alfalfa. Sample 33 is a composite
sample taken in a clover field near Paris, Illinois. Trouble was
being experienced in growing clover on part of the field. It was
thought that this might be due to the low sulphur content of this
part of the field, but soil analysis indicated that such was not the

1922] EATON—SULPHUR CONTENT OF SOILS 43

case. In fact, one of the samples from soil supporting a good stand
of clover contained decidedly less sulphur than did any of the
samples from the part of the field where there was no clover.
It would seem that some other factor than the sulphur content was
preventing the growth of clover. Since the results of analysis
revealed no reason for the failure to secure a good stand of clover on
part of the field, the data for all the samples were averaged in
order to secure an average value for the entire field.

TABLE V

SULPHUR, PHOSPHORUS, ‘AND ORGANIC MATTER CONTENT OF CERTAIN SOILS
OF CENTRAL STATES

Sampl 4 : ition
mee| Eacaton | Depth /Pareptnee) Tha per [Rewntags) baer | Tanke
i. Fremont, Ohio o-7 0.029 580 0.056 | 1120 6.87
2....| Fremont, Ohio 7-20 0.015 300 0.04 re) 6.72
3-..-| Plattesville, Wis. o- 0.028 560 0.034 680 4-47
4.. ttesville, Wis 7-20 0.038 760 0.040 800 5-62
§- attesville, Wis. o- 0.034 680 0.040 800 5.26
6. Plattesville, Wis 7-20 0.019 380 0.036 720 6.74
7. Naperville, Ill 0.021 420 O°. $900 1°10.17-
8....| Naperville, Ill 7-20 0.030 600 0.040 8 8.40
9....| Naperville, Til 0.040 800 0.051 | 1002 9.32

to....| Naperville, Ill 7-20 0.020 400 0.052 | 1004 9.71

at Gilman, I 0.058 | 1160 0.086 | 1720 | 13.53

12 Gilman, Ill 7-20 0.035 700 0.120 | 2400 | 10.76

t3....} Gilman, Ill. o-7 0.029 580 0.045 6.71

14....| Gilman, II. 7-20 0.036 720 0.057 | 1140 8.43

33-.-.| Paris, Ill. o-7 0.030 0.056 | 1120 7.40

Average surface soils............ 0.030 0.054 | 1080 8.00
Average subsolls......5........, 0.027 540 0.056 | 1120 8.05

Particular attention is called to the samples from Gilman,
Illinois. These were received from Mr. F. I. Many, who also sup-
plied the information in regard to the previous treatment of the
land from which the samples came. They were all taken in the
same field. Samples rr and 12 came from a part of the field that
during sixteen years had received applications of rock phosphate
and ground limestone. No other fertilizer had been applied to
the land for at least twenty years, and not much before that.
Samples 13 and 14 came from the check part of the field, which
had received no fertilizer of any kind. Clover had been grown on
the field once in four years, about half of the crop being plowed

44 BOTANICAL GAZETTE [SEPTEMBER

under. Clover was also grown on the check part of the field. Very
little grew here, however, and so there was not much to plow
under. Mr. MANN stated that the amount of phosphorus applied
to the land where samples 11 and 12 were taken would just about
equal that naturally present in the soil, so that these samples would
be expected to contain about twice the phosphorus of the samples
from the check portion. Table V shows this to be the case,
but the sulphur content of the surface soil of the fertilized land is
also double that of the check portion. This is rather to be expected,
when we compare the two in their organic matter content. Sample
11 is about double that of sample 13, and a high organic matter
content usually means a high sulphur content. The question,
however, is as to the source of supply of the sulphur. No sulphur
fertilizers have been applied to the land. There is the possibility
that, since the clover plant makes considerable growth during the
time of the heavy rains of the spring and again in the fall after
the rains start (times when the sulphur content of rainwater is
rather high), some of the sulphur might come from this source.
It is not believed, however, that the sulphur brought to the land
by the rain results in a net increase in the sulphur content of the
soil, on account of the large amount of sulphur lost in drainage,
although the amount lost in drainage is greatly decreased when
the land is covered by a crop. There is the additional possibility
that the clover roots bring up sulphur from the subsoil, depositing
it in the surface layers. As shown by the data, the subsoil of the
fertilized part of the field has about the same sulphur content as
the soil and subsoil of the check portion. Some of the other soil
analyses have shown that the sulphur content of various parts of
the same field may vary widely, when all parts of the field have
been treated alike so far as sulphur fertilization is concerned. If
this is true in the present case, then the difference in the sulphur
content of the two parts of the field would not be significant, but
the high organic matter content of the fertilized part of the field
would seem to indicate that these samples are representative, and
that there really is here a high sulphur content.

Considering all the samples of table V, it may be said in sum-
mary that the sulphur content on the average is not high in amount,

1922] EATON—SULPHUR CONTENT OF SOILS 45

although somewhat greater than the Maryland and Oklahoma soils,
and decidedly greater than the Alabama soils. The phosphorus
content is also rather low, although much higher than the sulphur
content. There is a fair amount of organic matter present on the
average in the soils. Reference was made previously to certain
soil analyses in Kentucky, Iowa, Kansas, Wisconsin, and Ohio.
Judging from my analyses and those referred to in the introduction,
many soils in the middle states need sulphur. Some of them are
well supplied, however, and on the average they seem to have a
higher sulphur content than the soils of either the Atlantic or
Pacific coasts, although not enough analyses or fertility experiments
have been made to make a positive statement as to this. On the
other hand, some of the soils are as low in their sulphur content
as any of the coast soils, so that it would not be surprising if sulphur
should prove beneficial on these soils. Demonstration experiments
on as many of the central states soils as possible are needed to
determine how generally sulphur is deficient.

Not many experiments of this kind have been performed. Cer-
tain investigators in Kentucky (25), Wisconsin (9, 28), and other
States, in pot experiments, have secured increased yields from
sulphur fertilization in the case of alfalfa, clover, radishes, rape,
turnips, mustard, tobacco, and soy beans. In field experiments,
JARDINE and Catt (11) attribute the increased yields in Kansas
secured by fertilizing alfalfa with acid phosphate to the phosphorus
of the acid phosphate, but here again there is the possibility that
the sulphur contained in the acid phosphate is at least partly
responsible for the increased yields. During the last few years the
Gypsum Industries Association has conducted a number of experi-
ments, seeking to determine the value of gypsum as a fertilizer
for crops. Beneficial effects have already been secured in a
number of cases. Such work should be extended.

Table VI records the results of the analysis of a few samples
taken within the environs of Chicago. Each sample includes a
number of borings and is therefore composite. The sample from
the South Chicago region was taken from what seemed to be a
natural prairie. This soil had probably never been fertilized.
The Midway, where samples 39 and 40 were taken, is quite often

46 : BOTANICAL GAZETTE [SEPTEMBER

manured. It was learned after analyses were made that samples
41 and 42 were taken from a part of the botany gardens that had
been filled in. The subsoil especially of this sample is not typical,
its higher sulphur content than the subsoils of the other soils
probably being accounted for by the filling in. The few Chicago
soils analyzed are all much better supplied with sulphur, phos-
phorus, and organic matter than any of the other soils analyzed.
It may be that soils of as high a sulphur content as these Chicago
soils might not need any sulphur fertilization, although in the
case of certain high sulphur-using crops the available sulphur
might not be sufficient. All the samples were taken from soils
overlaid with sod, and have a high organic matter content. There

TABLE VI
SULPHUR, PHOSPHORUS, AND ORGANIC MATTER CONTENT OF CERTAIN CHICAGO SOILS
_ Sample : Percentage} Lb. per | Percentage} Lb. per { Ignition
no. Location Depth sulphur a. cieiphorie rong value
39....| Midway 8 0.060 | 1200 0.100 | 2000 | 15.25
an) i 8-26 0.021 420 OO8s | TTz0.- | 10.24
41....| Botany Gardens o-8 0.055 | I1I0 6.075 + 1400 135770
42....| Botany Gardens 8-26 0.045 goo 0.068 | 1360 | 13.08
43....| South Chicago 0-8 0.069 | 1380 0.038 hae Mea fae Ge
44....| South Chicago 8-26 0.023 BOO CVS Se 15.12
Average surface OOM A) i sas 0,061 1220 0.070 1400 16.05
PAVeTage SUDSOUS (- 6545555. 0.029 580 0.060 1200 12.81

are probably many soils in Chicago of much lower sulphur and
organic matter content, which might need sulphur fertilizers.

It was thought interesting to determine how much of the total
sulphur of the Chicago soils might be accounted for by the sulphate
sulphur content. As is well known, where much soft coal is
burned, much sulphur is given off. It would be expected, therefore,
that rain would carry to the soil much more sulphur from a smoky
atmosphere than from one free from smoke. WARRINGTON (quoted
by Hart and Peterson (8)) gives the amount of sulphur carried to
an acre surface of soil at Rothamsted as about seven pounds per
year. Judging from their limited data, Hart and Peterson (8)
estimate about the same figures are correct for University Hill
Farm, Madison, Wisconsin. Data indicate a much higher sulphur

1922] EATON—SULPHUR CONTENT OF SOILS 47

content of the rainwater of cities. Some of my determinations
show several times as much sulphur in Chicago rainwater as in
rainwater collected in the country some distance from Chicago.
Most of the sulphur in rainwater is in the sulphate form. It might
be expected, therefore, that the sulphate sulphur present in the
Chicago soils might account for much of the total sulphur. Roughly
quantitative determinations showed an average sulphate sulphur
content of the three surface soils of table VI of 158 pounds per
two million pounds of soil. This is high, compared with the Iowa
soils as analyzed by Brown and KetLioce (2). They found an
average sulphate sulphur content of 59 pounds per two million
pounds of soil, but the sulphate sulphur present in the Chicago
soils accounts for comparatively little of the total sulphur. Most
of this is in the organic form, and the high sulphur content of the
soils is due mainly to the high organic matter content. That the
sulphate sulphur content is not higher may be accounted for prob-
ably by the ease with which sulphur in a soluble form is leached from
the soil.

Lyon and Bizzevt (14), MacIntire and co-workers (15), and
other investigators have performed lysimeter experiments. Lyon
and BizzE.t show that 3-6 times as much sulphur is lost in drainage
as is used by the crop, and when put in a soluble sulphate added to
the tanks, over one-half of the amount added in any one year was
removed in drainage the same year.

Table VII summarizes the data of tables I, II, IV, V, and VI.
Fig. 1 compares in a graphical way the sulphur, phosphorus, and
organic matter content of the five groups of soil. The Alabama,
Maryland, and Oklahoma soils are all low in sulphur, phosphorus,
and organic matter, the Alabama soils being especially deficient
in all three substances. The phosphorus, on the average, is not
much greater in amount than the sulphur. Although the central
States soils are better supplied with sulphur and phosphorus than
these three groups of soils, they would not be considered high in
either. The range in the amount of sulphur and phosphorus
present in the various soils is rather great. Certain of the soils
would be considered fairly well supplied with both sulphur and
phosphorus. The organic matter content of the soils is on the

48 BOTANICAL GAZETTE [SEPTEMBER

average fairly good, although here also the range is very great,
and certain of the soils are deficient in this respect.

The sulphur and phosphorus content of the Chicago soils is
fairly good, while the organic matter content is high. As is
brought out in connection with table VI, the samples are not
typical for the cultivated soils of Chicago and its environs. They
were taken in places where the organic matter had had a chance
to accumulate. Their high sulphur content is to be accounted
for mainly by their high organic matter content, the sulphur
brought down by the rain accounting for little of the total sulphur.
Although the Chicago samples should not be considered typical for
cultivated soils, they are perhaps typical of soils of any section
of the United States which have been in grass or any form of plant

TABLE VII

SUMMARY OF TABLES I, IT, IV, V, AND VI, GIVING AVERAGE OF SURFACE SOILS; SULPHUR
AND PHOSPHORUS IN POUNDS PER”“ACRE, IGNITION VALUE IN PERCENTAGE

Alabama Maryland Oklahoma |Central states} Chicago

Samhats: § or ae 256 460 480 600 1220
Phosphorus. 200. 7 go 580 694 1080 1400
Ignition value.......... 2.194 4053 5.528 8.00 10.05
Ratio ignition value to

Moe. area te oe 182.5 196.9 230.0 263.3 263.1

life for a number of years, or have been heavily manured. Such
soils would be expected to be well supplied with organic matter,
and to have a correspondingly high sulphur content. If conditions
are right for active sulphofication, there should be an abundance of
available sulphur. 7

A further study has been made of this relation between the
organic matter and total sulphur of the different groups of soils
by determining the ratio of the organic matter to the total sulphur.
As shown by table VII, this ratio is far from a constant. A 100
per cent increase in the organic matter content does not mean a
corresponding 100 per cent increase in the sulphur content. A
comparison of the ratios for the different groups of soils, and of
the figures for the sulphur content and the organic matter content
seems to justify the statement, however, that there is a general

1922] EATON—SULPHUR CONTENT OF SOILS 4G

correlation between the two, that a soil with a large amount of
organic matter also contains a large amount of sulphur. That
the correlation is not closer may be accounted for, at least in part,
by the fact that plants differ greatly in their sulphur content.
The source of the organic matter present in the soil has a great deal
to do with the amount of sulphur the soil contains. This fact
may account, at least partly, for the cases (shown by the tables
giving the detailed data of the soil analyses) in which there does
not seem to be any correlation at all between the organic matter
and sulphur content. A high organic matter content may be
correlated with a low sulphur content, but these cases should be
considered exceptions to the general rule that a soil containing a
large amount of organic matter also contains a large amount of
sulphur, a rule which is seen more clearly when the sulphur and
organic matter content of a number of soils are averaged. In
general, the sulphur content of soils is greater than that of the
corresponding subsoils.

Table VIII gives the number of crops that could be grown from
the amount of sulphur present in the various groups of soils as
summarized in table VII. Brown and Ketioce’s (2) figures
for the amount of sulphur removed by maximum yields of these
crops have been used. They assume that the entire crop is removed
from the soil. In the Maryland and central states soils, which
include the most important agricultural soils, the number of crops
supply of sulphur in the poorest soil and in the best soil is given in
the column “Range.” Table VIII shows that there is enough
sulphur present in most of the soils for comparatively few maximum
crops of such high sulphur-containing plants as alfalfa and potatoes.
The other crops contain less sulphur, and therefore a greater
number of maximum crops of these could be grown.

Most of the sulphur of the different soils is in the organic form
and unavailable for the plant, and it is not known how rapidly
sulphofication is making it available. When the sulphur content
of a soil is as low as it is in the Alabama, Maryland, Oklahoma,
and several of the central states soils, however, sulphofication may
hot produce enough available sulphur to secure maximum yields of
most crops. Considered from this standpoint, table VIII may

5° BOTANICAL GAZETTE [SEPTEMBER

not be very significant, except as another way of comparing the
sulphur content of the different groups of soils.

The sulphur content of maximum yields of the six crops given
in table VIII, according to the figure of BRown and KELLOGG,
totals 134.3 pounds; the total phosphorus content 128 pounds.
These are five of the most common crops, especially in the central
states. Judging from the soil analyses that have been made by

TABLE VIII

NUMBER OF MAXIMUM CROPS THAT MAY BE GROWN FROM AMOUNT OF SULPHUR PRESENT
THE FIVE SOIL GROUPS AS GIVEN IN TABLE VII

Alabama | Maryland| Range | Oklahoma ost Range | Chicago

GEG cere 16 28 oy eee iy 30 37 20-7 76
Wheat... 574. : 25 45 35-58 47 58 41-113} 119
Rt Ce ea 15 27 21-36 20 36 25-70 73
Potatoes: yi 2.4: Vd 14 II-I7 14 18 12-35 37
Cover... 2k. 19 35 27-45 36 45 32-88 93
Alfalfas. ooo. 5 Is 10 7-13 10 13 9-2 26

various investigators, the agricultural soils of the United States are
even more deficient in sulphur than in phosphorus. Although
considerable sulphur is added to the soil of rainwater, a larger
amount seems to be lost in drainage, some investigators stating that
three times as much sulphur is lost from the soil in drainage as is
added to the soil by the rain. It would seem possible, therefore,
that further investigation would prove that sulphur is as generally
needed as a fertilizer as is phosphorus.

EFFECT OF SULPHUR ON CHLOROPHYLL DEVELOPMENT, AND GROWTH
OF RED CLOVER AND SWEET CORN

Several investigators have reported a better color in plants
due to sulphur fertilization. Rermmer and Tartar (21), as already
stated, secured greatly increased yields of alfalfa from sulphur
fertilizers. They emphasize the poor color of the alfalfa on the
plats not fertilized with sulphur. Oxson (19) speaks of the same
thing in connection with experiments in Washington. The Massa-
chusetts station (16) reports like results, but the beneficial effect
on the color does not seem to be confined to the legumes. DULEY
(6) reports the same thing in the case of sweet corn, and DEMOLON

1922] EATON—SULPHUR CONTENT OF SOILS 51
(5) observed a darker green in the foliage of rutabagas, parsnips,
and beets fertilized with sulphur than in the check experiments.
An experiment was planned to try to determine the relation between
the sulphur and the chlorophyll content of the plants. STowELL’s
evergreen sweet corn and mammoth red clover were grown in
ordinary 12-inch flower pots. Thirty-six pounds of sand were
added to each pot. For series 1, 2, and 3 pure quartz sand was
used; for series 4, 5, 6, 7, and 8 a fine grade of torpedo sand sifted
free from stones and coarse material was used. Sulphur was added
to the sand, as shown in table IX. The figures in the table mean
that sodium sulphate and flowers of sulphur were added in such
amounts as to give the same amount of sulphur as contained in

TABLE IX

AMOUNT OF SULPHUR ADDED TO SAND CULTURES OF CLOVER AND
R

Series shade = sad sooner. a woe te oy og

Wiel ene a seater Bee te LN Nise Ca ku ee eek Co PC Ee ee ea
Bis in oes EN aa WN ee ae fos + SoM tea Oye aca airy. oe aranes
SP ech sank Ma aca s ok anace TO Ee a oa Oe eae es ade © oe Vin re Pees
Meta ene ee es Cates hace vir con Crs Seis Penn an ee en De:
Bre ee S00 5 ME Lea a ee
De iss otek ia pie SO Tae ph etre Pale Cen
Pees Ga BOO Se ea ee cua Oe a cia os
Deir dare eR eUw Ges eae ey atee ee ue ee 500

100, 300, and 500 pounds of gypsum per acre, or two million
pounds of sand. Each series was run in triplicate.

he gypsum and flowers of sulphur were thoroughly mixed with
the sand at the time the pots were filled. The sodium sulphate was
added in solution in three applications. The corn was harvested
sooner than had been planned, and received only two applications
of sodium sulphate. The sodium sulphate series in the case of the
corn, therefore, received two-thirds of the amount given in the
table. In addition lime was added at the rate of 1000 pounds per
two million pounds of sand. One week after the cultures were
Started 1 gm. of ferric chloride was added to the sand of each pot.
The corn was planted February 7. It had previously been placed
between moist filter paper, and at the time of planting all the

52 _ BOTANICAL GAZETTE _ [SEPTEMBER

seeds were fully imbibed and most of them had sprouted. The
clover was sown January 22, and on February 6, when the plants
were 4 inches high, they were transplanted to the sand. A pure
culture inoculum obtained from the Department of Bacteriology
of the University of Wisconsin was added to the sand containing
the clover on February 13.

The nutrient solution used was the same as that used by Kraus
and KRAYBILL (13), except that magnesium chloride was sub-
stituted for magnesium sulphate. Perhaps a solution better
suited to corn and clover might have been found, but it gave good
growth in both cases. It was made up as follows:

SOLUTION A SoOLuTION B

Per cent Per cent
Magnesium chloride.............. a Galen Witte. ie
Dibasic potassium chloride........ 2
Potassiuit nitrate. 0 2

Equal parts of A and B were diluted 1 to 70 with water and
then mixed. The solution was applied in this strength to the
corn. The solution applied to the clover was just half this strength.
Five hundred cc. of these solutions were added on an average of
once a week to the corn and the clover. While the plants were
small and the light poor, not so much was applied, but later the
supply was increased. Both the corn and clover grew well, but
no marked differences in color or size of plants developed in either
In fact, in the case of the corn, that in the control series was as
green as the corn of any of the other series. It was not deemed
the right kind of material for studying the effect of sulphur on
chlorophyll development, and no chemical analyses were made.

Since no marked differences in color or growth due to sulphur
deficiency had developed in the clover of the different series, it
was decided to modify the experiment somewhat. It was thought
the nitrate supply might be too high. On April 27 each series
was divided into two parts. The nitrates were kept up in one-
half of the pots and discontinued entirely in the other half, but
no marked differences in color had developed at the time the
experiment was stopped, on May 27. At this time the clover of
the control series was somewhat paler than the clover of the high

1922] EATON—SULPHUR CONTENT OF SOILS 53

sulphur pots, but it was not very marked. Also, no definite
gradation in color from the control series to the high sulphur series
was discernible. The microchemical analyses were made on
the clover of the control series and the clover of the high sulphur
series, in the latter case using mainly plants from series 8, the
gypsum series.

The most noticeable point in table X is that the nitrates, pro-
tein, and sulphates are greater in amount in the plants of the
high gypsum series. There was not much difference in the carbo-
hydrate situation in the two series. Leaves from plants of the
two series had about the same amount of reducing sugars and
starch. The petioles of the control plants contained more reducing

TABLE X

MICHROCHEMICAL ANALYSES OF CLOVER PLANTS OF CONTROL SERIES AND OF HIGH
SULPHUR SERIES; NITRATES DISCONTINUED May 27

CaSO, HIGH CaSO, NONE
Leaves Petioles Roots Leaves Petioles Roots
Nitrates. .... + ++ ++ + + +
Protein... ... + ++. + so + +
Sulphates.. . . ++ a oe ++. isis + +
IRAE Ss, + ++ a ++ ++
eae + +++. ++ + at +

Sugar than in the case of plants from the high gypsum series, but
the starch content of the petioles was about the same in both.
In the roots, the reducing sugar was about the same in amount in
both series, while the starch was greater in amount in the gypsum
series. These differences, while clearly evident, were not great
enough to permit any definite conclusions as to the relation of
sulphur to chlorophyll development in the clover plant.

REmer and Tartar (21), Miter (18), DuLey (6), and
Hart and TorrincHam (9) have shown that root development and
nodule formation are increased in clover and alfalfa by the use
of sulphur fertilizers. Prrz (20) has shown that sulphur causes
an increase in the nodule-forming bacteria of 2-3 fold. REIMER
and TarTAR have also demonstrated that sulphur increases the
nitrogen content of alfalfa 2-3 per cent. ScHERTz (26) has shown

54 BOTANICAL GAZETTE [SEPTEMBER

a close connection between the nitrogen and chlorophyll content
of Coleus leaves, so that it is possible that sulphur has at least part
of its effect through increasing the nitrogen content of the plant.
My work seems to indicate this, but more work is desirable before
coming to any definite conclusions. In the case of the non-
legumes, the activity of ammonifying and nitrifying bacteria of the
soil might be increased. The evidence is conflicting as to the
effect of sulphur on these organisms, some claiming a favorable
effect and some little effect. It is hoped to repeat this experiment,
both in the case of corn and clover, omitting the nitrates entirely
or keeping them very low. This should be done from the start;
then, if the sulphur does have its effect indirectly by increasing
the nitrogen supply through an increase in the number and activity
of these organisms, this effect should be apparent. Special pre-
cautions should be taken to exclude sulphur. Sulphur-free salts,
of course, should be used. The sand should be thoroughly washed
with distilled water, perhaps even boiled in acid and then washed
with distilled water, to eliminate any sulphur that it may contain.
If decided differences in color develop, as a result of sulphur —
deficiency, the microchemical analyses should be followed by
quantitative chemical analyses.

Table XI gives data concerning the effect of sulphur in different
forms and different amounts on the growth of sweet corn. As |
before stated, the. corn was grown with the idea of obtaining
material to study the effect of sulphur on chlorophyll development
in non-legumes. Since no difference in color in the different
series developed, the corn was harvested and the dry weight
determined, to see the effect of sulphur on the growth. It had
been growing about two and one-half months and was in tassel.
The details of the plan of the experiment have already been given.
The numbers in the column ‘‘Treatment” indicate that flowers of
sulphur and sodium sulphate were added in such amounts as to
contain the same amount of sulphur as present in 100, 300, or 500
pounds of gypsum per acre, or two million pounds of sand. The
percentage increase or decrease is based upon the dry weight.
The minus sign indicates a decrease.

Series 4 should not be considered, for from the first the corn
in two of the pots of this series did not grow well. At the time of

1922] EATON—SULPHUR CONTENT OF SOILS 55

harvest most of this corn was short and spindling. This is believed
to be due not to the sulphur treatment but to poor seed. Leaving
this series out of consideration, we see that flowers of sulphur and
sodium sulphate containing the same amount of sulphur as 100
pounds of gypsum, and gypsum at the rate of 500 pounds per
acre gave marked increased dry weights over that of the control.
The flowers of sulphur caused the greatest increase, 66.16 per cent,

TABLE XI

EFFECT OF DIFFERENT SULPHUR TREATMENTS ON GROWTH OF STOWELL’S EVERGREEN
EET CORN IN GREENHOUSE

: - Percentage
Series Treatment Moisture mag vent D — — . or
ees Control 87.62 266.7 33-E [ewes eee
. ebee baie Na.SO, at rate tak 100 |b.
gypsum per a 86.60 334.90 44.8 35-34
OS Flowers of sulphur. at same| ‘
Ogura 369.6 55-0 66.16
Beats Na,sO, ae amis ns 300 |b.
gypsum per 85.00 164.3 24.7 $6.27
Lge arse Flowers ts sulphur at same}
rate a 84.95 239.5 32.8 — 0.90
ae Dips Na,SO, ar sn ba 500 lb.
gypsum per 85.44 222.5 32.4 — 2.11
(EON aes whet of pale hue at same
s6 85.93 739.2 33-4 0.90
ene Gxpsum at rate of 500 lb.
Hee uP eh pena 82.76 agt.7 46.9 41.69

and gypsum was next with 41.6 per cent, sodium sulphate causing
35-3 per cent increased dry weight. It is hard to say why flowers
of sulphur and sodium sulphate in the larger amounts did not
bring about increased growth. The dry weight of these series is
about the same as the check.

There has been work indicating injury to plants by the acid
resulting from the oxidation of flowers of sulphur. Also some
have claimed injury from the alkalinity developed in the soil by
sodium salts. While this is a possibility, it is not emphasized.
The acidity should have been taken care of by the calcium carbon-
ate added to the sand. The literature shows that sulphur fertiliza-
tion of cereals has not given consistent results, and as a rule not a
very marked increased growth has been caused, so perhaps no
particular significance should be attached to the fact that series 5,

56 BOTANICAL GAZETTE [SEPTEMBER

6, and 7 show about the same dry weights as the check. The corn
of all the series where sulphur fertilizers were used had a lower
moisture content than the corn of the control series, the corn
fertilized with gypsum having about 5 per cent less moisture than
the control.

Summary

t. The Alabama, Maryland, and Oklahoma soils analyzed are
low in sulphur, phosphorus, and organic matter; the phosphorus
being not much greater in amount than the sulphur. The central
states soils are better supplied, on the average, in all three respects,
and decidedly better supplied with phosphorus than with sulphur.
Some of these soils might be considered to have a fair amount of
sulphur, phosphorus, and organic matter, while others are deficient
in these respects. The Chicago soils have a fairly good content
of phosphorus, and a rather high content of sulphur and organic
matter. Although the sulphate sulphur content of the Chicago
‘soils is high, this accounts for little of the total sulphur, most of it
being due to the large amount of organic matter present.

2. Most of the sulphur of soils is in organic form. There is a
general correlation between the sulphur and organic matter content,
soils of a high organic matter content having in general a high
sulphur content. The surface soils are in general higher in sulphur
than the subsoils.

3. Judging from the results obtained and the work of other
investigators, sulphur fertilization should prove quite generally
beneficial on the Atlantic coast and the Gulf coast. The same
thing may be true of the Pacific coast. Sulphur fertilizers are
probably not as generally needed in the central states, many soils
no doubt needing them, and many others not. Soil of a high
organic matter content, such as the Chicago soils, may not need
sulphur fertilizers except for high sulphur-using crops. In case
the sulphate sulphur is as great in amount as it is in the Chicago
soils, sulphur fertilizers might not be needed, even if the organic
matter content is low.. Attempts are made, in the case of several
soils, to correlate the sulphur, phosphorus, and organic matter
content with the production of the soils, previous treatment, or
other factors.

1922] EATON—SULPHUR CONTENT OF SOILS 57

4. No definite conclusions can be drawn from the data as to
the relation of sulphur to chlorophyll development in plants.
This may come about through the effect of the sulphur in increas-
ing the nitrogen content of the plants.

5. Flowers of sulphur and sodium sulphate, containing the same
amount of sulphur as 100 pounds of gypsum per acre, and gypsum
at rate of 500 pounds per acre, caused increased dry weights of
sweet corn of 35-66 per cent. Larger amounts of flowers of
sulphur and sodium sulphate gave no increases. The corn fertil-
ized with sulphur had a higher moisture content than the controls.
In the case of the gypsum series this amounted to 5 per cent.

The writer wishes to acknowledge his indebtedness to Dr.
WILLIAM CROCKER and Dr. SopHiA ECKERSON, under whose
direction this investigation was conducted. A part of the investi-
gation was conducted under a Research Fellowship from the
Gypsum Industries Association. Thanks are due the Association
for their kindness in furnishing the fellowship.

UNIVERsIty oF CHICAGO’

LITERATURE CITED

1. AMES, J. W., and Bortz, G. E., Sulphur in relation to soils and crops.
Ohio Agric. Exp. Sta. Bull. 292. 221-256. 1916.

2. Brown, P. E., and Kettoce, E. H., Sulphur and permanent soil fertility
in Iowa. Jour. Amer. Soc. Agronomy 7:97-108. 1915.

3- CARRIER, LyMAN, and co-workers, Alfalfa experiments. Va. Agric. Exp.
Sta. Bull. 207. 1-20. 1914

4. CROCKER, WILLIAM, History of the use of gypsum as a fertilizer (unpub-
lished).

5- Demoton, M. A., Sur 630 fertilisante du soufre. Compt. Rend.

Acad. Sci. 154 3524-526.

6. Dutey, F. L., Relation - slp to soil productivity. Jour. Amer. Soc.
Agronomy 8: pes 19

7. GRANTHAM, A. E., Alfalfa i in Delaware. Del. Agric. Exp. Sta. Bull. 110.

I-42.

8. Hart, E. B., and Pererson, W. H., Sulphur requirements of farm crops,
in relation to the soil and air sipely. Wis. Agric. Exp - Sta. Research
Bull. 14. 1-21. rorr.

9- Hart, E. B., and Torrincuam, W. E., Relation. of sulphur compounds to
plant nutrition. Jour. Agric. Res. 5 :233-250. 1915.

Id.

)
zi

BOTANICAL GAZETTE [SEPTEMBER

HILLEBRAND, W. F., The on g silicate and carbonate rocks. U.S.
Geol. Survey Bull. 422. 1-230.

. JARDINE, W. M., and Catt, L. E. "Alfalfa i in Kansas. Kan. Agric. Exp.

Sta. Bull. 197. be-Bioe IQ14.

. Kocu, F. C., Lecture and laboratory notes in tissue analysis. Course 37

in Department of Physiological Chemistry at the University of Chicago.
d

. Kraus, E. J., and Kraysrtr, H. R., Vegetation and reproduction with

re reference to the tomato. Oregon Agric. Exp. Sta. Bull. 149. 1-90.

g18.
‘ Evoke T. L., and Bizzett, J. A., Lysimeter experiments. Cornell Agric,

Exp. Sta. Mekioir 12. I-II

; 1OTS,
. MacIntrre, W. H., Wiis, L. G., and Hotpine, W. S., The divergent
il

effects of lime and aged upon the conservation of soil sulphur. So
Science 4 :231-235. 1917.

. Mass. Agric. Exp. Sta. Rep. 1914 (pp. 157, 1
. Methods of Analysis of the Association of Official Agricultural Chemists.

Washington. 1920.

. Mitter, H. G., Relation of sulphates to plant growth and composition.

Jour. Agric. Re: 17 :87-102. 1919.

Otson, G. A., and St. Joun, J. L., An investigation of sulphur as a plant
food. Wash. ante Exp. Sta. Bull. 165. 1-69. figs. 11. 1921.

Pr1z, W. J., Effects of elemental sulphur and of ealaus sulphate on
plant life. Jour. Agric. Res. 5:771-780. 1916.

. Remer, F. C., and Tartar, H. V., Sulphur as a fertilizer for alfalfa in

southern Oregon. Oregon Agric. Exp. Sta. Bull. 163. 1-40. 1919

. Roprnson, W. O., The inorganic alas % some important American

soils. U.S. Dept. Agric. Bull. 122. 1-27.

RoBINsON, W. O., STEINKOENIG, G. A., Hes Fay, W. H., Variation in the
chemical compouition of soils. U.S. Dept. Agric. Bull. 551. I-16. 1917.
SHEppD, O. M., The sulphur content some typical Kentucky soils. Ky.
Agric. Exp. Sta. Bull. 174. 213-250. 1913

, The relation : sulphur to ae fertility. Ky. Agric. Exp. Sta.
Bull. 188. 595-630. 19

. Scuertz, F. M.,A hac and physiological study of mottling of leaves.

Bor, Gaz. 71: 81-131. 1921.

. Swanson, C. O., and MItter, R. W., The sulphur content of some typical

Kansas soils and the loss of sulphur due to cultivation. Soil Science
3 3139-148. 1917.

TortincHam, W. E., Effect of spied: of ate supply on plant growth.
Wis. Agric. Exp. Sta. Bull. 228. 26.

EFFECT OF AUTOLIZED YEAST AND PEPTONE
ON GROWTH OF EXCISED CORN ROOT
TIPS IN THE DARK’

WILLIAM J. ROBBINS

(WITH EIGHT FIGURES)

In a previous paper? the writer described a simple method by
which the excised root tips and stem tips of higher plants can be
cultivated under sterile conditions, and some experiments in which
this method was used. These experiments showed that the excised
root tips of corn would make considerable growth in the dark in a
sterile nutrient solution containing mineral salts and glucose, and
but little when no carbohydrate was present. It was found, how-
ever, that the amount of growth which a corn root tip would make
under these conditions was limited. If the original root tips were
grown for ten days or two weeks in the dark in the nutrient solutions
containing glucose, and then their tips cut off and transferred to
fresh nutrient solutions, the amount of growth and production of
secondary roots was decidedly less in the second period than in the
first, and ceased entirely in the third. The following causes for this
cessation of growth were suggested: (1) an unbalanced condition of
the nutrient solution, (2) a deficiency of oxygen, (3) incompleteness
of the nutrient solution, that is, the lack of some constituent neces-
sary for continued growth. A consideration of the conditions of the
experiments and the results obtained suggested that the third pos-
sibility should be used as a working hypothesis. This assumption
does not eliminate the possibility that the cessation of growth is
due to one or both of the other two factors, or that it is due to some
factor not considered. It is merely used as the basis for further
experimentation.

ublished with soem of the Director of the Agricultural Experiment
Station, , University of Misso The writer cpm eal the kindness of D K.

Witson in supplying the Longfellow Flint corn u i s investigation, and the
assistance of Dr. W. E. MANevaL in making the naar caved in experiments

Mig

7 Ropsins, W. J., Cultivation of excised root tips and stem tips under sterile
conditions. Bor. Gaz. 732376-390. 1922

59] [Botanical Gazette, vol. 74

60 BOTANICAL GAZETTE [SEPTEMBER

Growth of roots attached and detached from grain

That the seed supplies material different either in kind or in
quantity from that present in the culture solution is evidenced by
the following experiment, in which a comparison was made of the
growth of roots attached to the grain and detached from the grain.
In this experiment corn grains were sterilized by W1Lson’s method
as before, and germinated on sterile agar in Petri dishes. After
germination, and when the roots were about 3 cm. long, some of the
grains were placed in socc. of sterile modified Pfeffer’s solution
plus 2 per cent glucose in 125 cc. Erlenmeyer flasks, and some of the
root tips were cut off and transferred to the same kind of solution
and culture flasks. All were placed in the dark at room temperature.
At the end of twelve days the roots attached to the grains had
gained 26.6 cm., had produced 102 secondary roots on the average,
and weighed per ten roots 0.5120gm. Those detached from the
grain had gained 12.4 cm., had eighty-three secondary roots, and
weighed per ten roots but 0.1138 gm. (table [).

TABLE I

GROWTH IN DARK OF ROOTS ATTACHED TO GRAIN AND DETACHED FROM GRAIN, IN
PFEFFER’S SOLUTION PLUS 2 PER CENT GLUCOSE

be Average.ori Average no. | D
Condition nal er co ae dav: secondary | per ro roots
(cm.) (cm.) roots (gm.)
Attached tO gral ee 2.9 26.6 102 0.5120
emai ee oe See ae we £7 12.4 83 0.1138

In tubes of 1 per cent agar a similar difference in the growth of
roots attached to the grain and detached from the grain was noted.
In fig. 1 the growth of an excised root tip at the end of two weeks in
modified Pfeffer’s solution plus 2 per cent glucose containing 1 per
cent agar, and the growth in the same period of time of a root which
was left attached to the grain are shown. Comparing the latter root
with the excised root, its greater length, greater size of secondary
roots, and greater diameter of root tip are clearly evident.

The effect of peptone and autolized yeast

If we assume that the stoppage in growth of an excised corn root
tip on continued transfers is because glucose, the mineral salts of

1922] ROBBINS—ROOT TIPS 61

Pfeffer’s solution, oxygen, and water are insufficient for continued
root growth, the natural place to look for the materials lacking is
the grain or the plant. Extracts of the young embryos including
both roots and tops, and of young seedlings a week or ten days old
did not benefit the excised root tips. In fact, these extracts used
in the proportion of the extract of one embryo or seedling to one
root tip showed a slight injurious effect upon the growth of the root.

Fic. 1.—Corn root tips originally about 2 cm. long: ( 1) excised root tip in Pfeffer’s
solution plus 1 per cent agar; (2) excised root tip in Pfeffer’s solution plus 1 per cent
agar and 2 per cent glucose; (3) root tip of root attached to grain in Pfeffer’s solution
plus 2 per cent agar.

Neither did creatinine, gylcocoll, or asparagin used at the concen-
tration of 100 ppm, 79 ppm, and 50 ppm respectively produce any
better growth. The first two substances were slightly injurious,
the last one no better than the check. Two experiments in which
the Ca(NO,), and KNO, of Pfeffer’s solution were replaced by
CaCl, and KCl, and in which the roots were carried through three
periods of culture, showed that the lack of nitrate somewhat
decreased the total amount of growth in length instead of increasing
it, as generally occurs in water cultures lacking nitrogen when the

ae BOTANICAL GAZETTE [SEPTEMBER

root is attached to the grain. Peptone and autolized yeast, how-
ever, were found to be distinctly beneficial. These two substances
were selected because they contained a variety of comparatively
simple organic nitrogenous materials, and because they are known
to be beneficial to the growth of lower plants, such as the bacteria or
the yeasts.

TABLE II

EFFECT OF PEPTONE AND AUTOLIZED YEAST ON GROWTH IN DARK OF CORN ROOT TIPS
CUT OFF AND TRANSFERRED

zr. June 21—July 4

Bone eis ales I 11.6 68 0.0487 4.5 6.8
INGORE. oes, 8 1.7 2.7 68 60 4.5 6.5
None..........: 8 1.9 12.8 63 0.0485 4.5 6.3

Nene. isi 8 1.6 Pe 8 0.0030 AGS 5.04
0.0 tO; enh 8 47 4.3 16.0 | 0.0283 6.5 6.5
0.02% yeast..... bay 2.2 19.90 | 0.0371 5.2 8.3
3. July 22—August 20
None. 054 3c: 8 rs ©.05 Cool ewes as 4.6
°. o4ch pectone 4 1.8 A 18 H.8 6.42
0.02% yeast..... 2 r6 5.2 21.0 | i ceeie ee 5.45
4. August 20-November 12

None 8 eee ee a ae ee re ee
oO. 04% pete: 3 2.0 1.6 ASS Pee i a OAS

0.02% yeast..... I 2.0 2.5 AiO ere oh ee or cae oe

The first experiment with peptone and autolized yeast was begun
June 21, 1920, and completed November 12 of the same year. The
second experiment extended from December 13, 1920, to February
5, 1921. Both experiments demonstrated that excised corn roots
whose tips were severed and transferred about every two weeks
would grow in the dark in sterile solutions containing peptone or
autolized yeast, glucose, and the salts of Pfeffer’s solution for four
to six two-week periods, while without the peptone or autolized

1922] | ; ROBBINS—ROOT TIPS 63

yeast growth stopped in the third two-week period. Autolized yeast
appeared to be somewhat more favorable than peptone. The
details of these two experiments are as follows.

Experiment 5.—In this experiment the method of culture was as
previously described. Grains of Longfellow flint corn were sterilized
by Witson’s hypochlorite method. The excised tips of the original
primary roots were grown in the modified Pfeffer’s solution plus 2

Fic, 2.—Effect of peptone at end of second period on growth of corn root tips in
dark; two root tips on left in Pfeffer’s solution plus 2 per cent glucose, two on right in
same solution plus about 400 ppm peptone.

per cent glucose. The root tips of these excised roots were cut off
after eleven days and transferred to the same solution, to the same
solution plus peptone, or to the same solution plus autolized yeast.
Further transfers were made as indicated in table II. Erlenmeyer
flasks of 125 cc. capacity containing 50 cc. of solution were used.
One cc. of a sterile 2 per cent solution of Difco peptone was added to
each flask containing peptone, and 1 cc. of a sterile 1 per cent auto-
lized yeast suspension was added to each flask containing auto-
lized yeast. This produced solutions containing approximately

64 BOTANICAL GAZETTE [SEPTEMBER

400 ppm of peptone and 200 ppm of autolized yeast. Both the
yeast and peptone were sterilized intermittently at 100° C. The
root tips were grown in the dark at room temperature.

The beneficial effect of the peptone and the autolized yeast began
to be evident toward the end of the second period of growth. From
the data in table II it can be noted that the root tips in the peptone
solution show distinctly greater growth in length, production of
secondary roots, and greater increase in dry weight. The maximum
increase in this period in the check was 3.2 cm. with eight secondary
roots, in the peptone solution 3.6 cm. with twelve secondary roots,
and in the yeast 5.5 cm. with nineteen secondary roots. The
appearance of two of the best root tips in the Pfeffer’s solution plus
glucose and in the same solution plus peptone at the end of the
second period is shown in fig. 2. A number of the roots in the pep-
tone solution, however, and still more in the autolized yeast solution
developed very abnormally. They became swollen, translucent,
water-soaked, and extremely brittle, and growth was stopped.
From later experiments the large number of these abnormalities is
believed to be due to the combined action of the peptone or yeast
and the comparatively high room temperature of July (about
30 ©).

The dry weights of the root tips in the yeast and peptone solu-
tions at the end of the second period were comparatively high, as
can be noted from later experiments. These high dry weights were
due to the large number of thickened and abnormal roots which
developed in this period in the yeast and peptone solutions. Of
the eight roots in the peptone only four were transferred, and of the
eight roots in the yeast only two were transferred. These grew in
the third period, however, while the check root tips did very little,
as can be noted in table II. The maximum growth in the third
period in the check was 0.3 cm. with no secondary roots, in peptone
7.8 cm. with twenty-nine secondary roots, in the yeast solution 9.4
cm. with forty secondary roots. The tips of three of the four roots
in the peptone solution were transferred and one of the two roots in
yeast. These grew in the fourth period, the maximum in the pep-
tone being 4.5 cm. with no secondary roots, and in the yeast 3.5 cm.
with four secondary roots. The one root in the yeast solution was

1922] ROBBINS—ROOT TIPS 65

lost by contamination. The results of this experiment, so far as
length increase is concerned, are presented graphically in fig. 3.

Determinations of the a
H-ion concentration of tty aa
the solutions used in this 2-1) 5
experiment were made by oe
GILLESPIE’s} method at
the beginning and at the
end of the first, second, +
and third periods. The
modified Pfeffer’s solution -&+
at the beginning of each am
period had a Py of 4.5. tottharhs
The addition of the quan- (>the
tity of peptone used made : Dui eee aes

. IG. 3.—Growtnh in length of root tips of corn in

“a mes es dark Ab. four periods; anaes aie modi-

? H oo aes | -bescoerhe ~— — 2 per cent dextrose
The autolized yeast had (check),
a similar though less Pp yr o #0 pom pon ore stl
marked effect, raising the aooidinie th wi period. j
P, to 5.2. The growth
of the roots made the check solution more alkaline (table II), raising
the P, in the first period to 6.3~-6.8, in the second to 5.04, and barely
affecting it in the third period. Both the yeast and the peptone
exerted a buffer action, and little change in the reaction was
produced in these solutions by the growth of the roots. It was
noted that in the Pfeffer’s solution containing glucose the change in
reaction was roughly proportional to the amount of growth which
the roots made. Root tips which grew but little raised the P,, from
4-5 to 5.1 in the first period; those which made the most growth
raised it as high as 6.8. Higher values than this have been obtained.
In one case root tips of Silver Mine corn grown for three months in
the modified Pfeffer’s solution plus 1 per cent cane sugar (inverted
in sterilizing) changed the P,, to as high as 8.4.

Experiment 1o.—In this experiment the methods followed were
as in the first experiment, but two concentrations of peptone were

3GiLtespie, L. J., Colorimetric determination of H-ion concentration without
buffer mixtures. Jour. Amer. Chem. Soc. 42:742-748. 1920.

—

(IPRS S
aaa
+

rast

WOerH | JW Gar!
Bes ae | 1 ES ii
Cok

eS i ke

re
ead |

}L]
da IB |
ima |

|
i eA
EE aigMie

66 BOTANICAL GAZETTE [SEPTEMBER

used instead of one. The excised primary roots of the germinated
grains were grown eleven days in the modified Pfeffer’s solution plus
2 per cent glucose. The tips were then cut off and transferred to
the same solution, or to the same solution plus autolized yeast or
peptone. Further transfers at intervals of two weeks were made, as
indicated in table III.

TABLE IL

EFFECT OF PEPTONE AND gio YEAST ON CONTINUED GROWTH OF EXCISED
co ROOT TIPS IN DARK

: Average origi-| Average gain | Average no. | Dry weight
Addition to Prerrer’s solu- |No. roots tips! nal length in length secondary | per 10 roots
tion+2% glucose (cm.) (cm.) roots (gm.)
1. December 13-December 24
|
INORG oe a ee 9 2.2 14.0 05 baie
None co) oy a 13 1.9 tA.9 SF 82 is yee
be peers een 10 1.95 12.9 98.8 ©, 1020
PRONE Soa sacs gn vee em we 18 I $235 72 | ere
2. December 24—January 8
ONE) SG ee ee 9 2.1 2.46 72 0.0058
200 ppm — yeast.. 13 4:9 4.8 at 0.0087
200 ppm peptone........ 9 2.05 2.9 16 0.0064
400 ppm pepto se ee oe 14 ap | 3:9 16.7 0.0097
3. January 8—January 22
NONE. le ee 7 1.8 0.3 ce Ea Be eriiawaaray ce
— oben — yeast.. 10 2.06 2.9 4.36 0.0032
oo ppm peptone........ 6 ed 0.3 2 Oe ci nig et
sere ppm as ea PG 12 2.0 1.4 1:6 0.0035
4. January 22-February 5
NOME 2s ree PE OSS Bop tyne pele eees i te ae eee. So ee
200 jen pam p yeast.. 9 ‘6 0.83 O06 hes aay
200 ppm peptone........ 6 1 Se 9.50 Ce i aes
400 ppm echols eeears a II ny | 0.28 Os es rere rar ary

Again, toward the end of the second period of growth, the bene-
ficial effect of the peptone and yeast was evident. In this case,
however, with the lower winter temperature (ranging around 22° C.
in the dark room used for incubation) the abnormalities so evident
in the first experiment were not so numerous, and most of the roots
were carried over into the third period. Here the check root tips
again stopped growth, while those root tips in the yeast and peptone

1922] ROBBINS—ROOT TIPS 67
continued to grow. They also grew in the fourth period, and of
seven root tips transferred from the solutions containing autolized
yeast, one grew from an original length of 1.8 cm. to 2.6 cm. in the
fifth period.

It can be noted in table III and in fig. 4, where the average gains
in length of the root tips in this experiment are represented graphi-
cally, that there is a continued decrease in the amount of gain in
length in each successive period in both the yeast and peptone

cad ; Li
HA iam
ls td le
a ase 8 Be
Shot
oe We a ty
ie i
te {tt
a aues tee 7 ae
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b. it 1
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!
a t
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HEE SNe tepid peas
Lf 22: <
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pate L i | } 5 we
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: : se queagenat' BERKS Oo

Fic. 4.—Growth in length of excised corn root tips in dark for five periods; solu-
tions dot were modified Pfeffer’s solution plus 2 per cent glucose (check), same solution
plus approximately 200 ppm or 400 ppm peptone (p 200, p 400) or 200 ppm of autolized
yeast (Y 200); numbers within circles represent number of root tips still growing in

each period in yeast extract.

solution. The decrease which occurs in the first period is the most
marked. The same holds true for the production of secondary roots
and for the dry weight produced in each period. The decrease is
most marked in the dry weight. The dry matter produced in the
second period, even in the presence of yeast or peptone, is only ;';
or ;'y of that produced in the first period. A consideration of the
data of both experiments shows that autolized yeast is superior in its
effect to peptone.

An observation made in this experiment as well as generally in
others should be recorded. The root tips of some of the excised

68 BOTANICAL GAZETTE [SEPTEMBER

roots in any series always develop abnormally. The root tip be-
comes clear and glassy, sinks to the bottom of the solution, and
almost ceases growth. When this occurs in the early periods of an
experiment the secondary roots become unusually long and well
developed, frequently attaining a length three or four times that of
the secondary roots of an excised root whose tip is developing nor-
mally. The appearance of a root whose primary tip became abnor-
mal and whose secondary roots show marked development is shown
in fig. 5. A normal root is shown in fig. 6. The latter figure also
illustrates the fact noted before that the secondary roots develop
from the convex side of the main root.

Effect of different concentrations of autolized yeast

While autolized yeast and peptone exert a favorable influence
on the continued growth of the excised root tips in solution cultures
containing glucose and the mineral salts of Pfeffer’s solution, never-
theless the increase in length and the production of secondary roots
and dry matter continuously decrease, until eventually growth
stops. If we are to determine the complete nutrient requirements
of a root by the method used, it will be necessary to find a set of
conditions in which the excised root tips will grow continuously and
produce approximately the same increase in length, number of
secondary roots, and dry matter period after period as the root tips
are cut off and transferred.

It was hoped that increasing the concentration of the favorable
factor already found would accomplish this. Experiments were
therefore carried out in which concentrations of autolized yeast vary-
ing from 10 ppm to 800 ppm were used. The results of these experi-
_ ments indicated that while 400 ppm were somewhat more favorable
than any of the other concentrations used, there was no marked dif-
ference in the effects of concentrations as low as 10 ppm and as high
as 800 ppm so far as the growth in the early periods was concerned.
In the later periods, however, the higher concentrations of yeast
were more beneficial. Two experiments were performed dealing
with this phase. The first extended from February 5 to April 16,
the second from April 3 to May 17, 1921.

1922 ROBBINS—ROOT TIPS 69

Fic. 5.—Excised corn root whose tip has developed abnormally; note develop-
ment of secanine ry roots

—Normal exc ised corn root tip; compare development of secondary roots
with 4 te of root in fig.

70 BOTANICAL GAZETTE [SEPTEMBER

Experiment 12.—The methods used in this experiment were
similar to those used in the previous experiments. The root tips
were grown at room temperature in the dark in 125 cc. Erlenmeyer
- flasks of Pyrex glass containing so cc. of solution. The original
excised primary roots were grown for the first period in the modified
Pfeffer’s solution plus 2 per cent glucose, and in the same solution
plus 80, 200, 400, or 800 ppm of autolized yeast or 200 ppm of Gold
Label gelatine, and transferred to fresh solutions of the same com-
position as in the first period. Further transfers were made as
indicated in tableIV. In addition, one set of root tips was grown for
six weeks in the Pfeffer’s solution containing 2 per cent dextrose
without transferring, and one set was grown in the same solution
plus 400 ppm of autolized yeast for six weeks without severing the
tips, and transferring.

The autolized yeast extract used in experiment 12 was prepared
by thoroughly boiling 2 gm. of autolized yeast with roo cc. of dis-
tilled water, filtering, and making up to the original volume with
distilled water. This 2 per cent extract of the autolized yeast
actually contained 0.3366 gm. of dry matter per socc., of which
0.0525 gm. was ash. An extract prepared in the same way was also
used in experiment 14. The actual concentration of autolized yeast
in the nutrient solutions to which yeast was added was about one-
third of the concentrations given, which are based on the weight of
the dry yeast as it came from the bottle. Table V indicates the
approximate amounts of dry material, organic matter, and ash
added to the culture flasks in the form of the yeast extract.

The data in table IV and the graphic representation of the
lengths in fig. 7 show that during the first period the autolized yeast
exerted no favorable influence on the growth of the roots. It was
not until near the end of the second period that the beneficial effect
of the yeast became evident. As was noted earlier, growth in the
Pfeffer’s solution plus 2 per cent dextrose fell off very markedly in
the second period, and stopped in the third. In the presence of
autolized yeast, however, the roots grew in the third and fourth
periods. The number which could be transferred was decidedly
reduced in the fourth period, however, but those which were trans-
ferred made some growth in the fifth period, and some of the roots

1922] ROBBINS—ROOT TIPS 7
TABLE IV
EFFECT OF DIFFERENT CONCENTRATIONS OF AUTOLIZED YEAST ON CONTINUED
GROWTH OF EXCISED CORN ROOTS IN STERILE CULTURE IN DARK
Ave origi- ig yee gain we no. | Dry weight
‘Addition to oe ssolu- | No. root tips tel es length n length come per ro roots
tion+2% g (cm.) "(em ) (gm.)
1. February 5—February 19
NOG fo Gt ee ae | 10 a 426° 67 ©.0940
60 ppm yeasts: 2 seo | Io bars) 12.0 62 0.0840
200 ppm yeast... 60.585 10 1.8 eG 60 0.0730
400: DDIM VEASE 5 So. 2b. Io 1.9 13.0 72 0.0820
800 ppm yeast.......... ike) 1.9 it 6 56 0.0630
200 ppm gelatine........ 10 oy 10.4 50 0.0624
2. February 19—March 5
DSS Gia warden p ee 9 2.3 356 9.6 0.0051
80 ppm yeast. ......... ine) 1.9 5.907 6.1 0.0056
200: ppm Yeast) pi...) se) 2.16 =. 71 14.0 0.0116
400 ppm. Yeast. 4045 os ite) 2.0 5-4 13.2 i:
OO Ppl Veast. oo. as To ra 4 5-5 9.0 0.0104
200 pelatine:; 20! fo. 10 1.85 2.14 3:7 0.0044
3- March 5-March ro
ON a 9 1.9 0.2 2.9 0.0015
80 ppm yeast. .2....° ., 8 1.8 4.0 6.5 0.0035
200: ppm yeast. a 8 2.7 4:2 4.4 0.0043
#00 ppiy Yeast. oe. 3 8 1.9 3.6 9.6 0.0055
800 ppm yeast.......... 6 1.6 4.4 10.7 0.0110
200 pelating... 2.2.5.0: cf 1s O.1 a eg
4. March ro-April 2
ppm yeast........... ees oe ares eG 1.15 | 2.2 | 0.0030
200 Ppm yeast oe. 8 t.9 1.60 0.4 2.0050
400 ppm yeast. 2.55.0. 5 ; 8 1.6 1.95 3.5 0.0040
800 ppm yeast.......... 5 1.46 2.60 5.4 0.0046
SO PEIBTING ig ee i es ee ee ei er ee
5. April 2-April 16
80 ppm yeast.......... + 1-8 0.7 ot
200. DDm yeast. 665.605... | 4 eh 0.5 Oe ee ae a
400 ppm yeast.......... 2 r.65 a A te gran suten ee
pm her, 4 1.55 0.8 BODE NG rakes
February 5—March 19
tae emis cle alle 9 2.0 20.4 84 0.0898
jen fom VOR 13 1.93 20.57 97 0.0635

73 BOTANICAL GAZETTE [SEPTEMBER
grew in the sixth period. All the roots still growing were acciden-
tally lost in the sixth period.

An examination of the data in table V and the curves in fig. 7
shows that none of the yeast concentrations prevented the gradual
decrease in length gain, secondary root production, and dry matter

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1G. 7.—Growth in length of excised corn root tips in dark for five periods of

transfers; solutions used were Pfeffer’s solution plus 2 per cent glucose (check), and
same solution plus 80, 200, 400, or 800 ppm autolized yeast.

elaboration. The rate of decrease was very rapid at first, but
became less so as the periods passed. The increase in the rate of
growth in 400 ppm of autolized yeast in the fifth period is apparent
only. It is due to the fact that two roots only out of the eight of the
fourth period grew in the fifth period. Their growth was excellent
throughout the experiment, but decreased continuously. The

1922] ROBBINS—ROOT TIPS 73

increases in length for one of these roots, no. 32, for the five periods
were as follows: 11.2, 6.5, 4.9, 4.5, and 1.3 cm., and the secondary
root production was 58, 12, 3, 4, and o. For the other, no. 39,
the increases in length were 13.0, 11.5, 8.3, 6.9, and 5.4 cm., and the
secondary root production was 82, 51, 25,16,and 17. These figures
show a continuous decrease in length. They also emphasize the
fact, which has been observed continuously in this work, that the
root tips act consistently as individuals period after period. A root
tip which develops well in the first and second periods usually con-
tinues to show a superior growth in the later periods.
TABLE V
APPROXIMATE ACTUAL MATERIAL, ASH, OR ORGANIC MATERIAL

N AUTOLIZED YEAST EXTRACT ey Cpe URE
SOLUTIONS IN EXPERIMENTS 12 AN

Concentrations of | Total dry

autolized yeast matter added
in culture solutions! Total dry Ash ( ) Organic rs

— as _|matter (ppm)| ‘*S” ‘PP™m (ppm) ts rl

bott rot ‘dese ESE Sori (gm.)
TO. a4 0.5 3.0 0.00016
40... 13.5 2.0 LIcS ; 5
Boe fe) 29.6 4.0 23.0 0.0013
200. . 67.0 10.5 56.5 0.0032
400. . 134.0 Bi 113.0 0.0067
800. . 268.0 42.0 226.0 0.0134

The difference in the effect of the various concentrations of yeast
was not great, and appeared most sharply in the later periods.
Thus, so far as length is concerned, the gain in 80 ppm of yeast was
as great in the second and in the third period as in any of the other
concentrations. The secondary root production and dry weight
produced, however, were greater in the higher yeast concentrations
even in the second period. It was not until the fifth period that
200 ppm of yeast showed its inferiority to 400 ppm; 800 ppm of
yeast apparently was somewhat too concentrated. The addition
of 200 ppm of a colloidal material like gelatine to the culture solu-
tion did not favorably affect the development of the roots. It
should be noted that root hairs were found on the root tips in the
gelatine solution at the end of the third period. Excised roots which
did not have their root tips severed and transferred at intervals

74 BOTANICAL GAZETTE [SEPTEMBER

(table VI) made just as much growth in length in a period of six
weeks in Pfeffer’s solution plus 2 per cent glucose as in Pfeffer’s
solution plus 2 per cent glucose and 400 ppm of autolized yeast.

TABLE VI

GROWTH OF EXCISED CORN ROOTS IN STERILE NUTRIENT rasa ti IN DARK; IN ONE
CASE ap a yimoema ISED ROOT TIPS NOT TRANSFERRED; IN OTHER TIPS CUT OFF
AND T SFERRED TO FRESH cantina SOLUTIONS AT iach OF TWO WEEKS,
powtiiopes FROM DATA IN TABLE

Average sessing on
1 Average |Dry weight

Addition to Prerrer’s solution | Transfers | No. roots se fe Tength no. seco} ~ ale per 10

(cm.) (cm.) ary roots {roots (gm.)

February 5—March 19

inva d a emaed woes nee None 9 2.0 20.4 84 0.0898
a min autolized yeast...}........ 13 1.93 20.57 | 97 0.0635
February 5~March 19
UR Ed ee eet GNCES wiles 3 9Q-10 t.7 15.8 719.5 oO.1
pon apni autolized yeast...|........ 22.0 94.8 | 0.0971
TABLE VII

EFFECTS OF ie ae AND 80 PPM OF AUTOLIZED YEAST EXTRACT ON GROWTH OF EXCISED
RN ROOT TIPS IN STERILE NUTRIENT SOLUTIONS IN D

ay / Average origi-| Average gain| Average no. | Dry weight
Addition to Prerrer’s solu-
. No. roots nal length in ‘ieweth secondary | per ro roots
tion+2% glucose (em.) ‘cmn,) nate (gm.)
r. April 3-April 17
NONE i ei ea es 10 +57 pS | 65 0.1054
NONE. ea 10 os 11.i2 Oe pices es eee
ONE Ss ce eas ey to +75 11.25 OS fie cee wenee
NODE. sot se kay at .. 1.68 12.22 71 0.0826
2. April r7—April 30
ae cacy rane Near 8 soe a. 25 7:5 9.0027
IO DOM Yeast... cis: 5 1.96 3.48 9.9 0.0047
40 ppb yeast; 2... z 1.9 2.5 O08 olives ees
86 ppm Yeast: i oa 3 2.0 2.8 Ce ee eee
3. April 30~May 14
a Ville Obes eee 8 1.4 2 ° gah kes
50 Pom YeRst. . 5.2 ee. 5 1.8 ss oe ie ee eeg or
40 ppm yeast. 2.2.55). 2 1.8 13 Corr dees ke
So ppm yeast oo... 2 1.6 ae a le so aes

1922] ROBBINS—ROOT TIPS 75

The secondary root production in the autolized yeast culture was
somewhat greater and dry matter somewhat less in this case.

If we compare the growth of roots which had their tips severed
and were transferred twice to fresh solutions during a six weeks’
period with those which grew continuously undisturbed in the
solution, we find (table VI) that in Pfeffer’s solution plus 2 per cent
glucose the total increase in length and production of secondary roots
when the tips were severed and transferred was less than when they
were left undisturbed; the dry matter was greater. When yeast
was present the length and secondary root production were not
affected by the transfers; the dry weight was greater.

The original P, of the Pfeffer’s solution plus 2 per cent Sede
was 4.5. The roots which grew for six weeks without transfer
changed the reaction to P,, 6.3. The original reaction of the Pfeffer’s
solution plus 2 per cent glucose and 400 ppm of yeast was Py, 5.2.
The roots which grew for six weeks without transfer changed the
reaction to a P, of 6.24.

a a a pit
Experiment 14—The FPtHR4 oH
methods and general condi- am 4 t !
tions were the same in this ex- : Pe ttt
periment as in experiment 12. AH ete
In this case, however, concen- = = seecace
trations of yeast of 10, 40,and FR scan a ‘
80 ppm were used. The root Eyogqpoct it
tips were grown for the first Ag HHtEE cH
period with no addition to the zon
nutrient solution, the yeast amen wanes
being added in the second we
period. Unfortunately one of Weote
the flasks containing the con- - antl

centrated yeast extract was Fic. 8.—Growth in length of excised corn
. . . root tips in dark for three periods of trans-
contaminated with bacteria, fers; solutions used were Pfeffer’s solution
and most of the cultures were plus 2 per cent glucose, and same solution
lost in the second period due plus 10, 40, or 80 ppm of autolized yeast.
to the contamination, leaving but two root tips in each of the con-
centrations, 40 ppm and 80 ppm. From the data in table VII
and the graphic representations in fig. 8 it can be noted that the

i
76 BOTANICAL GAZETTE [SEPTEMBER

growth in 10 ppm of autolized yeast in the second period compares
very favorably with that in 4o ppm or 80 ppm of yeast in the
same experiment. In the third period the development in the
solution containing 1o ppm of autolized yeast was better than in
either 40 or 80 ppm of yeast. If, however, we compare it with the
previous experiment in which a larger number of root tips were
grown in 80 ppm yeast, we can see that the development was con-
siderably less in to ppm than in 80 ppm of yeast. This substan-
tiates the general expression of the effect of autolized yeast in these
experiments, namely, that in the first period it has no beneficial
effect, in the second period there is little difference between the
effects of 10, 40, 80, 200, 400, and 800 ppm; but the later the period
the more evident does the beneficial action of the higher concentra-
tions appear.
Discussion

While excised corn root tips which are grown in the dark for
about two weeks in Pfeffer’s solution plus 2 per cent glucose, and
which have their root tips cut off and transferred to fresh solutions
at intervals of two weeks, show a continued decrease in the rate of
growth and stop growth in the third period, the addition of small
amounts of peptone or autolized yeast permits them to grow for as
long as six periods before growth ceases.

Two possible explanations for the action of the peptone and
autolized yeast suggest themselves: (1) the autolized yeast or the
peptone supplies something which the root requires for its continued
growth and which is not included in the salts of Pfeffer’s solution,
water, glucose, and free oxygen; (2) the autolized yeast or peptone
balances the solution, performing a function which could be accom-
plished by a readjustment of the relative quantities of the salts of
Pfeffer’s solution or their equivalents, of water, of glucose, and of
free oxygen. A definite decision between these two possibilities
cannot be made from the data at hand. The majority of the results
reported in this paper, however, would seem to be explained best on
the assumption that the mineral salts of Pfeffer’s solution, glucose,
free oxygen, and water are insufficient for the continued growth of
the root cells of corn, and that this deficiency can partially be sup-
plied by autolized yeast or peptone.

1922] ROBBINS—ROOT TIPS 77

That the effect of the peptone or autolized yeast is not protective is
indicated by the fact that a colloidal material like gelatine is not bene-
ficial, and by the fact that the beneficial action of the yeast does not
appear in the first period of two weeks, or even in six weeks when the
excised roots do not have their tips cut off and transferred to fresh
solutions. The assumption, however, that the seedling root contains
some substance or substances derived from the grain which are not
contained in the basic nutrient solution and which are supplied by the
peptone or autolized yeast would explain: (1) That root tips trans-
ferred show less feta growth isos those not transferred. The hypo-
thetical mat fractionated in the transfers, and the transferred
root is limited in the second and third periods by a deficiency of these
materials, which can partially be supplied by the peptone and
autolized yeast. (2) That in the presence of autolized yeast root
tips transferred show as much growth as those not transferred.
The hypothetical substances fractionated in the transfers are sup-
plied by the autolized yeast. (3) The fact that with the cessation of
growth of the root tip of an excised root there occurs an excessive
development of secondary roots. The hypothetical materials which
are not used in the growth of the main root tip are utilized for growth
by the meristematic tissue of the secondary roots.

Whatever the cause of the beneficial action of the autolized
yeast,’ its effect is limited in some way, as is evidenced by the fact
that the various concentrations of yeast produce no correspondingly
increased benefits, and the Pfeffer’s solution containing peptone or
autolized yeast and glucose will not permit continued growth.

Summary
1. Corn roots attached to the grain grow much more rapidly
under sterile conditions in the dark in Pfeffer’s solution plus 2 per
cent glucose than do root tips detached from the grain.

k of space precludes a summary at this time of the voluminous literature

H A T, HANniG, Bo LEY, W: , BACHMAN, LoE ;
FULMER, NELSON and SHERWOOD, ose s, and others who have dealt previously
with the problem of the necessity of accessory substances for plant growth, or

es:
who have attempted to cultivate single ak or isolated parts of higher plants. Some
of the more recent papers on this abies not cited in the earlier publication by the
writer are given at the end of this paper. A review of the subject indicated is planned
for a later publication.

78 BOTANICAL GAZETTE [SEPTEMBER

2, When excised root tips of corn are grown under sterile condi-
tions for about two weeks in the dark in Pfeffer’s solution plus
2 per cent glucose, and their root tips are severed and transferred to
fresh solutions at intervals: (a) growth stops in the third period;
(b) the addition of peptone or autolized yeast permits the root tips
to grow for 4-6 periods; (c) a concentration of 200 ppm of gelatine,
100 ppm of creatinine, 79 ppm of glycocoll, 50 ppm of asparagin,
or the corn embryo extract used show no beneficial effect; (d) in
Pfeffer’s solution lacking nitrates and containing 2 per cent glucose
a little less total growth is made than in Pfeffer’s solution containing
nitrates and 2 per cent glucose; (e) approximately 400 ppm of pep-
tone is more efficient than 200 ppm; (f) autolized yeast is more
beneficial than peptone; (g) the beneficial effect of the autolized
yeast does not appear in the first period of growth; (/) concentra-
tions of 10, 40, 80, 200, 400, and 800 ppm of autolized yeast (equiva-
lent in dry matter to about one-third the concentrations given)
show no marked difference in their beneficial effect, especially in the
early periods; (z) the higher concentrations of yeast evidence a some-
what greater beneficial effect in the later periods than the lower
concentrations.

3. When the total growth of excised corn root tips whose tips are’
cut off and transferred twice in a six weeks’ period is compared with
that of root tips left undisturbed, then (a) in Pfeffer’s solution plus
2 per cent glucose in the dark the total growth in length and produc-
tion of secondary roots are less, the dry weight is greater; (6) in
Pfeffer’s solution plus 2 per cent glucose and 400 ppm of autolized
yeast there is no difference in the growth in length or secondary
root production; the dry weight is greater.

4. When the growth of excised root tips left undisturbed for six
weeks in Pfeffer’s solution plus 2 per cent glucose is compared with
the growth in the same solution to which 400 ppm of autolized yeast
is added, there is no difference in total length. The secondary root
production is somewhat less and dry weight somewhat greater.

5. Excised corn root tips act as individuals.

6. The growth of the secondary roots of an excised root is much
greater when the primary root tip stops growth than when it con-
tinues to grow normally.

University or Missouri
Cotumsta, Mo.

1922] ROBBINS—ROOT TIPS 79

LITERATURE CITED

1. BACHMAN, FREDA W., rea requirements of certain yeasts. Jour.
Biol. Cha 39: 235-258. I

. Botromiey, W. B., The aves of certain food substances for plant
growth. Ann. Botany 28:531-539. 1914.

. Futmer, E. I., Netson, V. E., and rick F. F., The nutritional
requirements of yeast. I. The réle of vitamines in the growth of yeast;
II. The effect of the composition of the medium on the growth of yeast.
Jour. Ae Chem. Soc. 43:186—199. 1921

. GILLEsPIE, L. J., Colorimetric hettmination of hydrogen-ion concentration

without Gites mixtures. Jour. Amer. Chem. Soc. 42:742-748. 1920.

Loes, J., Rules and mechanism of inhibition and correlation in the regenera-

tion of Bryophyllum calycinum. Bor. GAz. 60: 249-276. 191

MacDona.Lp, M. B., and McCottoum, E. V., The coltbrations of yeast in

solutions of purified een a Biol. Chet. 45°307-311. 1921.

MockeErwwcE, F. A., VII. The occurrence and nature of plant

growil-orenioting substances in various manurial composts. Biochem.

Jour. 14:432-450. 19

Rossiys, W. J., The eubidia of excised root tips and stem tips under

sterile conditions. Bor. Gaz. 73:376-390. 1

Witiams, R. J., Vitamines and yeast oe Jour. Biol. Chem. 46:

113-118. 1921

. WEBER, F., dicmkone in Pflanzenreich. Naturwiss. Wochenschr. 35:
241-253. 1920

ms
°

LEAVES OF THE FARINOSAE*
AGNES ARBER
(WITH PLATES I-III)
Introduction

In papers published in this and other journals during the last
few years (ARBER 1-10) I have dealt with the results of the applica-
tion of the phyllode theory to the leaves of various groups of
monocotyledons. The present paper discusses, from this stand-
point, the leaf structure of the families associated by ENGLER (11)
in the cohort Farinosae. Examination of this group is a matter
of some difficulty to a British botanist, since the eleven families
which it includes are represented in Europe by one species alone,
Eriocaulon septangulare With., and even in cultivation compara-
tively few genera belonging to these families are to be found. I
have thus been unable to carry this study so far as I should have
wished, because it has been necessary to rely almost entirely on
limited quantities of herbarium material, which, in the case of
the many fibrous-leaved members of the Farinosae, is peculiarly
intractable to sectioning. McLran’s (14) method of preparing
dried material has proved invaluable, however, even in the case of
plants which have lain in herbaria for many years. The specimen
of Cephalostemon affinis Koern., for instance, sections of which are
represented in fig. 26 A-C, was collected by Spruce in South
America as long ago as 1853.

I am indebted for material to the Director of the Royal Botanic
Gardens, Kew; the Keeper of the Department of Botany, British
Museum (Natural History); Mr. L. Ropway, of Hobart, Tasmania;
and Professor A. C. SEWARD.

I propose in the first place, taking the families in the order in
which they appear in ENGLER’s Pflanzenfamilien, briefly to describe
the principal types of leaf met with in the cohort, and then to
discuss their interpretation.

This paper represents part of the work carried out — the tenure of a
Geadey FJetcher-Warr Studentship of the University of London

Botanical Gazette, vol. 74] [80

1922] ARBER—LEAVES OF FARINOSAE 81

Flagellariaceae
I hope to describe the leaves of this family in a later paper, so
I will omit all discussion of them here; their most unusual feat-
ure is that, in the genus Flagellaria, they have tendril apices.

Restionaceae

In this family, which consists of nineteen genera, plants with
radical leaves are rare. The genus Anarthria, however, forms a
notable exception, for it has basal leaves recalling those of Jris,
which may either be ensiform or “radial.” Fig. 3 A represents
the transverse section of the limb of Anarthria scabra R.Br. It will
be seen that it has a type of anatomy resembling that of an Acacia
phyllode, the bundles, which are in two series lying to right and
left of the median plane of the leaf, having their xylems directed
inward. The palisade parenchyma is interrupted at very short
intervals by bands of fibers, one of which occurs between each of
the main bundles and the epidermis, while others are associated
with the smaller bundles, or occur independently. Fig. 3 B shows
the margin of such a leaf, with the median bundle, on a larger
scale. Two of the fibrous bands (/) are visible, and it will be seen
that, in the marginal region, the palisade parenchyma passes over
into thick-walled elements without contents. The epidermal cells
also increase in size and in the thickness of their sclerised walls as
the margin is approached. Fig. 4 A-C shows the leaf of Anarthria
gracilis R.Br., which, instead of being ensiform like that of A. scabra,
is radial. The limb (C), in which the fibrous sheaths of the bundles
with their extensions to the epidermis form a conspicuous feature,
is almost cylindrical in section. The leaves of Anarthria, however,
are not typical for this family, in which it is usual to find cauline
leaves alone. Such leaves generally have a well developed sheath,
succeeded by a relatively unimportant limb, which may be flattened
or cylindrical, but is often reduced to a mere point (examples occur
in Dovea, Elegia, Lepyrodia, and a number of other genera).
Fig. 1 A shows the appearance of the leaf of Restio tremulus R.Br.
It has a sheathing base (s) which more than surrounds the axis,
forming a ‘‘wrap-over.”” The same peculiarity in other members of
this family may be carried to a further point; in a species of

82 BOTANICAL GAZETTE [SEPTEMBER

Thamnochortus, the sheathing base of the scale leaf is described by
VELENOVSKY (18) as surrounding the axis spirally, and, according
to his fig. 358, its attachment forms more than two complete turns
round the axis. Both sheath and narrow, flat limb of Restio trem-
ulus are fibrous (fig. 1.B, C), and toward the apex of the limb
there is a marked increase in the lignified and sclerised tissue
(fig. 1D). The leaf of Leptocarpus peronatus Mast., with its
sheathing base and limb reduced to a mucro, is represented in fig. 2.
In the case of Elegia deusta Kth. the leaf apex is more solid, and
includes a ring of bundles (10, fig. 5 A, B).

Centrolepidaceae

The leaves of the Centrolepidaceae are usually small, with a
sheathing base and an awl-like or threadlike limb. Gaimardia
australis Gaudich. (fig. 5 A-C) may be taken as an example.
There is a sheathing leaf base and an awl-like limb, traversed by
three bundles inclosed in fibrous sheaths. The leaves of this
family may be of a more reduced type, however, as in Centrolepis
aristata R. and S. In this plant I have found one bundle,
traversing both sheath and limb (fig. 11 B, C). Gorse (13),
on the other hand, describes and figures the leaf anatomy of this
species as belonging to an extremely reduced ensiform type, with
a second bundle above the median bundle, resulting from the fusion
of two laterals. Although I have not found this structure in the
only two foliage leaves which I was able to examine, I have seen it
in two of the bracts from the base of the inflorescence (6, fig. 11 A).
These bracts are well developed structures with a sheath and limb,
closely resembling the foliage leaves.

Mayacaceae

The very delicate leaves of the single aquatic genus Mayaca,
of which this family consists, are traversed by a single vascular
strand (fig. 27. A). Several species figured in the Flora Brasiliensis
(17) have a bifid leaf apex, such as is shown here for M. fluviatilis
Aublet (fig. 278). It will be seen that the vascular bundle (vb)
takes no part in the bifurcation, but terminates below the fork.

1922] ARBER—LEAVES OF FARINOSAE 83

Xyridaceae

This family consists of two genera, Xyris and Abolboda. Xyris,
which includes about forty species, has a leaf with a sheathing
base and an ensiform limb, recalling that of many members of the
genus Iris. In Xyris Wallichii Kth. (figs. 12 A-C) and X. brevifolia
Mich. (fig. 18 A, B) the single bundles alternate to right and left in
the flattened limb. Fig. 18 B shows the marginal strand of Xyris
brevifolia, which is peculiar in the possession of a conspicuous
mass of fibers adjoining the bundle on the xylem side, whereas
such a fibrous strand is more usually developed outside the phloem.
As POULSEN (16) has already shown, the vascular bundles of the
leaves of X yris may either be single or associated in groups of two
ormore. Figs. 13 and 14 show bundle groups in the case of X. asper-
- ata Kth. (trachyphylla Mart.) and X. anceps Lam. These bundle
groups may attain considerable complexity; that represented in
fig. 13.B (X. asperata) consists of nine strands imbedded in a
common fibrous sheath. Although the flattened ensiform leaf
type is usual in Xyris, it is not universal. PouLsEN (16) has
figured a species (X. feretifolia Poulsen) in which the transverse
section of the leaf limb is oval, the distance between the adaxial
and abaxial margins being only about half as much again as the
widt

In Xyris the leaf epidermis is generally thick-walled. It may
retain much the same character at the two margins as on the flanks
of the leaf (X. Wallichii, fig. 12 C), or the elements at the margins
may be considerably elongated, forming a fibrous border to the leaf
(X. anceps, fig. 14 B-D). In this case the marginal elements,
instead of standing out horizontally, slope downward, with the
result that they are cut obliquely in transverse sections passing
through the leaf border, which at first glance thus suggest that
the epidermis is multi-layered in this region (fig. 14 D).

Xyris gracilis R.Br. is significant as possessing sheathing
leaves, in which the limb may be reduced to a mere point, and in
which the leaf base forms practically the whole organ (fig. 17).
These leaves may be compared with those of the second genus of
Xyridaceae, Abolboda. I have examined the leaves of A. grandis

84 BOTANICAL GAZETTE [SEPTEMBER

Griseb. var. minor, and find them to be traversed by a single
series of normally orientated bundles, corresponding to those in
the sheath leaves of Xyris gracilis (fig.17 C). A. Poarchon, as figured
by SEuBERT (17), has an acuminate apex to the foliage leaf, while
it also has bracts which terminate in a “cornet,” recalling that
described by Hatter in the case of the sepals of certain dicotyle-
dons (see reference and discussion, 10). It is probable that the
apex in both foliage leaf and bract of A. Poarchon Seub. is a vestigial
petiole, and is morphologically equivalent to the ensiform limb
of Xyris.
Eriocaulaceae

The Eriocaulaceae have both cauline and radical leaves of a
simple type. The two principal genera are Eriocaulon and Paepal-
anthus, both of which include more than a hundred species. Fig.
19 A shows the general internal structure of the “British species of
Eriocaulon, E. septangulare With. A large proportion of the
leaf is occupied by lacunae, separated by lamellae, each of which
includes a single normally orientated bundle. Fig. 19 B shows one
lamella with its vascular strand on a larger scale. A fragment of
a diaphragm (d) with intercellular spaces between its cells is seen at-
tached to the lamella on one side. In E. cuspidatum Dalz. the limb
terminates in a mucro (fig. 19 D), while in EF. Wallichianum Mart. f.
submersa the tip of the ribbon leaf is minutely truncate (fig. 19 C).
In this aquatic species, as in so many water plants, there is an
increase of the tracheal tissue near the leaf apex, and there are
indications of water stomates and possibly an apical opening, but
in herbarium material it is difficult to identify these structures
with certainty. The leaves of certain species of Eriocaulon may
be much reduced; in the aquatic E. setacewm L. the fragile linear
leaf, traversed by a single bundle, recalls that of Mayaca. In
the case of Paepalanthus I have examined one species, P. speciosus
Gardn. Here, as in Eriocaulon, there is one series of normally
orientated bundles in the leaf. The large epidermal cells are a
striking character.

Rapateaceae

The leaves of this family are much larger and more complex

than those of the Eriocaulaceae; they may show a definite differ-

1922] ARBER—LEAVES OF FARINOSAE 85

entiation into sheath, petiole, and limb (Rapatea longipes, fig. 24).
A curious feature common to the leaves of various members of the
family is their tendency to asymmetry. The leaf sheath, as
ENGLER points out in the Pflanzenfamilien, is folded, but the
median bundle does not occupy the trough of the fold, and the
limb correspondingly is not of equal width on either side of the
midrib. These features are shown in fig. 24, Rapatea longipes Spr.;
fig. 25 A, B, R. angustifolia Spr.; and fig. 26 A, B, Cephalostemon
affinis Koern. In the last species the sheath is peculiar, since it
thins out markedly at the fold, which is quite remote from the
median bundle, whose position is marked externally by a ridge of
fibrous tissue (/) adjacent to the lower surface (fig. 26 A). This
ridge can also be recognized in the limb (fig. 26B). The
lacunate character of the leaf tissue in Rapatea angustifolia Spr. is
indicated in fig. 25 C, which also shows the median bundle with
its fibrous sheath, and the small fibrous strands which run beneath
the epidermis. The details of the median bundle of the limb of
Cephalostemon affinis are seen in fig. 26 C.

Bromeliaceae

The leaves of the Bromeliads are often of a simple type, with a
broadly sheathing base prolonged into a linear to ovate limb.
In some cases, however (Tillandsia usneoides L. fig. 20 A, B),
there is a marked distinction between the sheathing leaf base and
the limb, which has a definitely petiolar character. In other cases
the main part of the leaf suggests a leaf base, but there is a solid
apical region which may correspond to the limb of Tillandsia
_ usneoides on a reduced scale (10). The figures of Aechmea gamo-
sepala Wittm. in the Flora Brasiliensis (15) show that the foliage
leaves in this case have an acuminate apex, while the outer perianth
members terminate in an elongated mucro, which is probably
equivalent to the ‘‘cornet”’ in the case of Abolboda Poarchon Seub.,
discussed in a preceding paragraph.

Commelinaceae

The leaves of this family differ from most of those hitherto
considered in their very complete differentiation. They usually

86 BOTANICAL GAZETTE [SEPTEMBER

have a conspicuous sheath, sharply marked off from a limb, from
which it may or may not be separated by a distinct petiolar region.
Fig. 9 represents the leaf of Streptolirion volubile Edgw., in which
all these parts are well developed. In Commelina, Aneilema, and
Tradescantia there is a striking range of form in the limb, which
in different species shows (within each genus) gradations from
linear to ovate.
Pontederiaceae

Fig. 8 A represents what is perhaps the most complex type of
leaf met with in the Farinosae, that of Eichhornia speciosa Kth.
(Pontederia crassipes Mart.). The ligular sheath (lig. s, fig. 8 A, B)
with its lobed apex, almost suggesting a second leaf blade, to which
attention has been drawn by Gttick (12), is, as he points out,
unparalleled among monocotyledons; it may perhaps be remotely
compared with the curious frill-like top of the ochrea of a Poly-
gonum from Java, figured by VELENOvskKY (18, fig. 277). The petiole
of E. speciosa is dilated, and terminates in a limb, which, as shown
in a previous paper (1), possesses both normal and inverted bundles
(fig. 8C). In this paper it was recorded that inverted bundles
occurred in the limb of Eichhernia, Pontederia, and Heteranthera.
The family also contains three other genera, Monochoria, Reussia,
and Hydrothrix. In Monochoria plantaginea Kth. I have now
been able to observe that inverted as well as normal strands occur,
and in a very small fragment of the leaf of Reussia subovata Solms,
the only material available from this genus, I again found both
types of strand. It has thus been possible to establish the occur-
rence of inverted strands in five genera of the Pontederiaceae;
the sixth, Hydrothrix, is an aquatic plant in which it is useless to
look for this anatomical peculiarity, since, as GOEBEL has shown,
the leaf is so much reduced as to be traversed by one vascular
strand alone (1).

The shape of the limb in the Pontederiaceae ranges from the
narrow, almost linear form sometimes met with in Monochoria
plantaginea, to broader types with a cordate base, such as Ponte-
deria nymphaefolia Kth., or with an auricled base, such as that
illustrated in M. hastaefolia Presl (fig. 7).

1922] ARBER—LEAVES OF FARINOSAE . 87

Philydraceae

This small family consists of four species assigned to three
genera. Sections were secured of three of these species, one
belonging to each genus. The monotypic Philydrum lanuginosum
Banks (fig. 22) has an ensiform leaf, whose shape and plan of
vascular anatomy recall Anarthria scabra R.Br.; the leaf, however,
is conspicuously lacunate. Pritzelia pygmaea F. Muell., repre-
senting the second of these monotypic genera, is related to Phi-
lydrum in its leaf structure, very much as Anarthria gracilis is
related to A. scabra. The leaf of Pritzelia has a sheathing base
(fig. 21 4) and a limb, which so closely approximates to radial
structure that it is not possible to determine from internal evidence
which is the median bundle (fig. 21 B). The leaf contains a
number of large, solitary, acicular crystals (c, fig. 21C). The
leaves of the third genus, Helmholtzia, have been described as
equitant and ensiform, but Dr. Starr has been so kind as to inform
me that in both the two species of which the genus consists,
H. acorifolia F. Muell. and H. glaberrimum Hook. f., the vaginal
portion of the leaf is strongly keeled, and that this keel runs as a
midrib throughout the “vertical” limb. The limb is thus expanded
in a plane at right angles to the truly ensiform limb of Philydrum.
In accordance with this difference of construction, the leaf anatomy
of the species which I have been able to examine, H. acorifolia,
proves to be dorsiventral, with palisade parenchyma on the adaxial
surface (fig. 23 A, B). The most striking feature of the leaf from
the present standpoint is that, despite its dorsiventrality, it is
characteristically phyllodic in structure, containing, besides
normally orientated bundles (mb), others that are inverted (7b).
Fig. 23 C shows the inverted group from the upper side of the
midrib, in greater detail.

Conclusions
CLASSIFICATION OF LEAF TYPES IN FARINOSAE

In the preceding pages the treatment of the leaves of this
cohort has been almost exclusively descriptive, but I propose now
to consider the interpretation of their morphology. The most

88 BOTANICAL GAZETTE [SEPTEMBER

concise way is probably by means of a classification, based on the
phyllode theory, of the principal types of leaf‘ enumerated in
dealing with the various families. On this basis the leaves of the
Farinosae fall into the following six groups:

1. Phyllodes consisting of a sheathing base, and an ensiform limb
equivalent to a petiole flattened in the vertical plane; for example,
Anarthria scabra R.Br. (Restionaceae), fig. 3; Xyris (many species)
(Xyridaceae), figs. 12, 14, 18; Philydrum (Philydraceae), fig. 22.

2. Phyllodes consisting of a sheathing base, and a limb departing
little in character from a normal petiole and containing an arc
or ring of bundles; for example, Anarthria gracilis R.Br.
(Restionaceae), fig. 4; Elegia deusta Kth. (Restionaceae) (10,
fig. 5A, B); Gaimardia australis Gaudich. (Centrolepidaceae),
fig. 5; Xyris teretifolia Pouls. (Xyridaceae) (16, fig. 3); Pritzelia
pygmaea F. Muell. (Philydraceae), fig. 21.

3. Phyllodes essentially similar to (2), but in which the petiolar
limb is reduced to a mere point; for example, Leptocarpus peronatus
Mast. (Restionaceae), fig. 2; Eriocaulon cuspidatum Dalz (Erio-
caulaceae), fig. 19; some Bromeliaceae.

4. Phyllodes similar to (3), but further reduced until they
consist of leaf bases alone; for example, many Eriocaulaceae and
Bromeliaceae.

5. Phyllodes in which the whole or the distal region of the petiole
is flattened in the horizontal plane into a pseudolamina, containing
inverted as well as normal bundles; for example, Pontederiaceae
(figs. 7, 8); Helmholtzia acorifolia F. Muell. (Philydraceae), fig. 23.

6. Phyllodes in which the whole or the distal region of the
petiole is expanded in the horizontal plane to form a pseudolamina
without inverted bundles; for example, many Commelinaceae;
Rapatea (Rapateaceae), figs. 24, 25.

COMPARISON WITH LEAVES OF OTHER COHORTS

One of the most striking results elicited by a general study of
monocotyledonous leaves is the way in which certain leaf types
recur again and again in this group, among plants by no means
closely allied to one another. The leaves of the Farinosae afford
many examples of these parallelisms. I will confine myself to an
attempt to trace some of the relations between the leaf types of

1922] ARBER—LEAVES OF FARINOSAE 89

the Farinosae and those of two other cohorts, Helobieae and
Liliiflorae; the Liliiflorae include those monocotyledons most
nearly related to the Farinosae (11), while the Helobieae are
somewhat more remote.

The ribbon leaves of certain aquatic species of Eriocaulon
recall the leaves of a corresponding form met with so frequently
among the Helobieae (7), although, if my interpretation be correct,
the ribbon leaves of Helobieae are of petiolar nature, while in
those of Eriocaulon merely the leaf base is represented. Although
the proportion of the parts is so different, it is-such a leaf as that
of Restio tremulus (fig. 1 A), rather than that of a submerged
Eriocaulon, which is equivalent to the ribbon leaf of, for instance,
Cymodocea nodosa of the Potamogetonaceae (7). On the other
hand, those leaves of the Farinosae in which the limb, although
linear, is rather awl-like than ribbon-like, such as Tillandsia
usneoides (Bromeliaceae, fig. 20), and Gaimardia australis (Centro-
lepidaceae, fig. 5), may be closely compared with Cymodocea
manatorum (7). The venation of the limb of Streptolirion volubile
of the Commelinaceae again (fig. 9) resembles that of Alisma
parnassifolium (7). A contrast with the Helobieae, however, is
furnished by Monochoria hastaefolia (fig. 7), whose venation is
essentially different from those of the species of Sagittaria,
which it recalls in the outline of its pseudolamina (7). Turning to
more detailed structure, the inverted bundles in the leaf limb of
the Pontederiaceae and of Helmholizia find their analogue in those
of certain Hydrocharitaceae.

The occurrence of the ensiform leaf in the Farinosae, both
in the Restionaceae, Xyridaceae, and Philydraceae, is another
instance of the widespread distribution of this leaf type among the
monocotyledons. It is known from the Helobieae, Spathiflorae,
Liliiflorae, and Microspermae, as well as in the Farinosae. Not
only in form, but also in internal structure, this type of leaf shows
remarkable uniformity in the different groups. Xyris Wallichii
(fig. 12.4) and X. brevifolia (fig. 18.A), with their alternating
bundles, can be paralleled in Jris (1, 6). The fibrous margins,
also, which are so marked a feature of the ensiform leaves of many
Liliiflorae (6), reappear in Xyris. For comparison with the leaves

go BOTANICAL GAZETTE [SEPTEMBER

of the Farinosae, fig. 6 A and B show a section of the ensiform
limb of Hewardia tasmanica Hook. (Liliaceae). It will be seen
that in the distribution of the marginal fibers it resembles both
Tritonia (fig. 10), and Xyris Wallichii (fig. 12 C) and X. anceps
(fig. 14 D). This similarity is also carried into the details of the
vascular system. Fig. 6 A shows examples from the limb of
Hewardia of opposite bundles imbedded in a common fibrous
sheath, and thus resembling the pair of bundles from the limb of
Xyris montivaga Kth., shown in fig. 15. With this may also be
compared the paired bundles of Tofieldia of the Liliaceae (1),
Tetroncium of the Juncaginaceae (7), and Tritonia (fig. 16 A, B)
and Moraea Robinsoniana (6). These bundle pairs are not only
characteristic of the ensiform leaves of monocotyledons, but may
be found also among the Acacia phyllodes, with which I believe
these leaves to be homologous; they occur, for instance, in Acacia
neurophylla (6). In addition to these bundle pairs, which clearly
originate by more or less complete fusion of strands belonging to the
opposite sides of the phyllode, Xyris also shows bundle groups of a
different nature, illustrated here in the case of Xyris asperata
(fig. 13 A-C) and X. anceps (fig. 14 A). These find their parallel in
the tribe Johnsonieae of the Liliaceae (5). In the limb of Arno-
crinum Drummondit Endl. there are bundle groups imbedded in
fibers, which may be compared with those of Xyris asperata.
It is true that they do not, as in the case of Xyris, occur in an
ensiform leaf, but the ensiform leaf type is found in Johnsonia,
to which Arnocrinum is probably more nearly related than it is to
the five other members of the tribe.

The Farinosae furnish additional evidence for the close relation-
ship of the ensiform and ‘‘radial” types of leaf. This relation,
to which attention has already been called, both in the case of the
leaves of the Liliiflorae and of the phyllodes of Acacia, is dis-
played with special clearness in Jvis, among whose species there
are examples of both forms of leaf, and also of intermediate types.
In the Restionaceae, Xyridaceae, and Philydraceae there are
comparable cases. Within the genus Amarthria both types are
found (ci. figs. 3 and 4), and the same is true of Xyris (cf. figs. 12,
14, 18 with PouLsEN’s fig. 3 of X. teretifolia, 16); while the ensiform

1922] ARBER—LEAVES OF FARINOSAE gI

leaf of Philydrum (fig. 22) may be compared with the “radial”’
leaf of the related genus Pritzelia (fig. 21).

The type of leaf consisting of a sheathing leaf base terminating
in a more or less cylindrical apex, which I interpret as a reduced
petiole, occurs both in the Farinosae and Liliiflorae. For instance,
the leaf of Elegia deusta Kth. (Restionaceae) is closely similar to
that of Distichia clandestina Buch. of the Juncaceae (10). The apical
tendril of Flagellaria (Flagellariaceae). also recalls that of Gloriosa
and other Liliaceae. I hope to discuss the morphology: of these
leaf tendrils in a later paper.

To complete the parallel between the leaves of the Farinosae
and those of the Liliiflorae, it may be noted that the limbs of the
Pontederiaceae and of Helmholtzia, with their inverted bundles, to
some extent approach those of certain species of Allium (5), and
of such Amaryllids as Zephyranthes (8); while the similarity in
shape of the cordate leaf limb of the Commelinaceous climber,
Streptolirion volubile (fig. 9), and that of various Dioscoreaceae and
Liliaceae is of wider interest, since it is an example of the recur-
rence of a form which appears again and again among monocotyle-
dons. In former papers (1, 4) I have brought together a number
of instances, from this class, of leaves with a cordate base; the
list of families in which leaves of this type are found may now be
increased to ten by the addition of the Stemonaceae, Amaryllidaceae,
and Hydrocharitaceae. This comparison between the leaves of the
Farinosae and those of the Helobieae and Liliiflorae emphasizes
again the important part which parallelism of development has
played in the evolution of the monocotyledonous leaf. The
tendency for related stocks (even those whose affinity is far from
close) to progress along corresponding lines is no doubt a very
general feature of evolutionary history, although its prevalence is
only gradually receiving full recognition. The fact that, in the
monocotyledonous leaf, such parallelisms are displayed to an
almost exaggerated degree, becomes to some extent explicable, if
this organ is regarded as a phyllode consisting of leaf base and
petiole alone. The loss of the lamina would inevitably impose
restrictions upon the further evolution of the leaf, by confining
its potentialities within a narrowed boundary. It might thus

Q2 BOTANICAL GAZETTE [SEPTEMBER

induce a tendency to the repetition of a definite series of forms,
monotonous in the basic features of their construction, but endlessly
varied within their given limits.

Batrour LABORATORY
CAMBRIDGE, ENGLAND

LITERATURE CITED
1. ARBER, AGNES, The phyllode theory of the monocotyledonous leaf, with
special reference to anatomical evidence. Ann. Botany 32:465-s501. 1918.
s e vegetative ar ee of Pistia and = Lemnaceae. Proc.
Roy. Rec. B. g1:96—103. 1

2. , Leaf-base cape pas the Liliaceae. Bor. GAz. 69:337-340-
1920.

4. , Tendrils of Smilax. Bor. Gaz. 69:438-442. pl. 22. 1920.

5 , On the leaf structure of certain —— considered in relation to

the phylicds theory. Ann. Botany 34:447-4
6. ————,, The leaf structure of the Iridaceae, ‘nnabdeela in relation to the
phyllode esti Ann. Botany 35: 301-336. 1921.
———.,, Leaves of the Helobieae. Bor. Gaz. 72:31-38. pl. 1. ci
prpenn of certain Amaryllids. Bor. Gaz. 72:102-105.
e , On the development and morphology of the leaves af nes,
Proc. Roy. Soc. B. 93: 249-261. 1922.
, On the leaf-tips of certain monocotyledons. Linn. Soc. Jour.
Bot. 46: 467-476. 1922
11. ENGLER, A., Die systidtnatinchse Anordnung der monokotyledoneen Angio-
spermen. Abbas di. Akad. Wiss. Berlin. Abhandl. Il. 1-55. 1892.
12. Gitck, H., Die Stipulargebilde der Monokotyledonen. Verhandl. Nat.-
Med. Vereins Heidelberg. N.F. 7':1-96. pls. 1-5. 1901.
13. GorBEL, K., Organographie der Pflanzen. Zweite Auflage. Teil 1.

oem

Allgemeine Onganographie 1913.
14. MCLEAN ., The utilization of herbarium material. New Phytol.
45: ote.
15. a Oe Sratbecae in Martius, C. F. P. von, Flora Brasiliensis
: part 3. 1892.

16. Pobisel V. A., Anatomiske Studier over Si yels Shhertens vegetative
Organe. Videnskab. Meddel. Naturhist. Forening Kjgbenhavn. pp. 133-
152. pls. 2, 3. 1892 for 1801.

. SEUBERT, M., Xyridaceae and Mayaceae, in Martius, C. P. F. von, Flora
Brasiliensis. 3: part 1

18. VELENOVSKY, J., Venisihiends Morphologie der Pflanzen. Teil 2. 1907.

Lal
~J

EXPLANATION OF PLATES I-III
Throughout, xylem (xy) shown in black; phloem (ph) in white; and
fibers (f) dotted; Jac, lacuna; pp, palisade parenchyma; mb, median bundle;

1922] ARBER—LEAVES OF FARINOSAE 93

ep, epidermis; s, sheath; pet, petiole; /, limb; #, node; ax, axis; in all sections
of equitant leaves, the identity of abaxial and adaxial margins has had to be
decided on internal evidence, owing to fragmentary character of herbarium
material available.

PLATE I

Fic. 1 A-D.—Reslio tremulus R.Br.: A, axis bearing leaf (X}); B, trans-
verse section sheath of leaf (X14); C and D, transverse section limb of another
leaf (X23); D nearer apex than C.

Fic. 2.—Leptocarpus peronatus Mast., axis bearing leaf (3).

Fic. B.—Anarthria scabra R.Br.: A, transverse section leaf limb
(X14), section slightly reconstructed at Gpnet margin; B, dorsal (abaxial)
margin of A

Fic. 4 A-C.—Anarthria gracilis R.Br., transverse section one leaf: A,
sheath peels slightly reconstructed at margins of arene B, basal part of
limb; 2 limb (X 23).

G. 5 A-C.—Gaimardia australis Gaudich.: A, leaf (X33 circa); Band C
icv. section of one leaf (X77); B, sheath; C, limb.

Fic. , B.—Hewardia tasmanica Hook. (for comparison): A, transverse
section leaf limb (X23); B, upper margin of A (X77)

Fic. 7.—Monochoria hastaefolia Presl, limb of leaf to show venation (X34).

Fic. 8 A~C.—Eichhornia speciosa Kth.: A, small leaf to show dilated
petiole and ligular sheath (lig.s) (4); B, top of sheath from A, viewed from
adaxial side to show three ligular lobes (X}); C, transverse section through
margin of leaf limb in A, in direction of arrow (X14); 7b, normally orientated
bundles; ib, inverted bundles.

Fic. 9.—Streptolirion volubile Edgw., axis bearing leaf (X 4).

Fic. 10.—Tritonia, garden hybrid (for comparison), margin of ensiform
leaf ( : ab 3).

. 11 A~B.—Centrolepis aristata R and S.: A, axis of small plant bearing
bithnaeees inclosed in bracts (0, 0), foliage leaf to right (X}3); B, transverse
section sheath foliage leaf (X23); B, transverse section limb (X77); bs, bundle
sheath, consisting of one inner thick-walled layer, and one outer layer of
larger cells with thinner walls. .

PLATE II

Fic. 12 A-C.—Xyris Wallichii Kth.: A, transverse section leaf limb

(X23); B, stomate from A (198); C, margin of A (X108).

1G. 13 A-C.—Xyris asperata Kth. (trachyphylla Mart.): A, transverse
section transition region between sheath and limb (X23) to show bundle
groups; B, bundle group marked x in A (X77); group of four bundles (;, b:,
b;, b,), in common fibrous sheath, from transverse section of leaf limb (X 318).

1G. 14 A-D.—Xyris anceps Lam.: A, transverse section limb of leaf
(X23); 61, single bundle; 6,, group of two bundles; 6;, group of three bundles;
B, apex of leaf limb viewed as solid object (X23); C, fibrous margin of leaf
viewed as solid object (X77); D, transverse section margin of A (X77).

94 BOTANICAL GAZETTE [SEPTEMBER

Fic. 15.—Xyris montivaga Kth.: pair of opposite bundles (xy, and pfhr,
xy, and ph) in common fibrous sheath (318); similar to 6, in fig. 14 A
(X. anceps).

Fic. 16 A, B.—Tritonia (garden hybrid) for comparison, lettering as in
fig. 15; fibers represented in black (instead of white with double lines indicating
thickness of walls, as in other figures): A, pair of opposite bundles from trans-
verse section of leaf limb (318); B, similar pair of bundles, but with
xylems fused (318

Fic. 17 A-C.—Xyris gracilis R.Br.: A, leaf consisting mainly of leaf
sheath, with reduced limb (/); B, apex of another reduced leaf in which limb
is absent (both natural size); C, transverse section of leaf shown in B (slightly
enlarged).

Fic. 18 A-B.—X-yris brevifolia Mich.: A, transverse section leaf limb
(X23); B, marginal bundle such as that marked x in A (X193).

1G. 19 A~D.—Eriocaulon: A and B, E. septangulare With.; A, transverse
section of limb of leaf (X23); B, lamella marked x in A (X77); we, upper
epidermis, /e, lower epidermis; d, fragment of diaphragm seen in surface view;
C, E. Wallichianum Matt. f. submersa, apex of leaf (<4); D, E. cuspidatum
Dalz., eae of leaf to show mucro (<4).

Fic oA, B.—Tillandsia usneoides L., transverse section leaf (X23):
A; POS B, ‘ion

PLATE Ul

Fic. 21 A-C.—Pritzelia pygmaea F. Muell., transverse section leaf:
A, sheath; B, limb (X23); orientation of B uncertain; C, margin of sheath in
A (X77) to show stomate (s/) and crystals (c).

Fic. 22.—Philydrum lanuginosum Banks, transverse section limb of leaf
(X14).

Fic. 23 A-C.—Helmholtzia acorifolia F. Muell., A and B, transverse sec-
tion limb of leaf (X23): A, midrib region (mr); B, margin, to show normally
orientated bundles and bundle groups (vd) and inversely ovicatated bundles
and bundle groups (ib); C, inverted bundles of midrib from section similar to
A (X77).

Fic. 24.—Rapatea loupe Spr., small leaf (<4).

Fic. 25 A-C.—Rapatea angustifolia Spr.: A and B, transverse section leaf
(x14); A, sheath; B, limb; C, median bundle (mb), of limb in B (X77).

Fic. 26 A-C.—Cephalostemon affinis Koern: A, B, transverse section
leaf (X14); A, sheath; B, limb; C, median bundle of limb (X77).

Fic. 27 pes —Mayaca fluviatilis Aubl.: A, leaf (x4); B, leaf apex
(X14); vb, vascular strand. .

BOTANICAL GAZETTE, LXXIV PLATE I

Restio (1)

hria (Be4)

Heward(e’
(for comparison) > as

ichhomia (8)

is Nj
SB

Centrolepis(l 1)

(\OTritoma

(for compat ison)
de

Streptolirion. 9 ',
ARBER on FARINOSAE

BOTANICAL GAZETTE, LXXIV PLATE II

acilis

le
: Eriocaulon (19) é

ry)
SS

ARBER on FARINOSAE

BOTANICAL GAZETTE, LXXIV PLATE iif

Pritzelia( 21)

Phil sie 8)

| Rapatea
Y (24525)

ae
A

Ceph alostemon

(A ; v4 R ‘ oSee é
2 Peet Cate:

mn as

ARBER on FARINOSAE

INHERITANCE OF FRUIT SHAPE IN
CUCURBITA PEPO. I
EpmMuND W, SINNOTT
(WITH THREE FIGURES)

During the past few years much progress has been made in our
knowledge of the inheritance of quantitative characters. We know
much less, however, about the factors which control the interrela-
tionships between these various size characters, and which thus
determine the shape of the organism. The present paper is a pre-
liminary report on some investigations dealing with certain phases
of shape inheritance in the summer squash.

For the past six seasons the writer has been carrying on some
breeding work with a number of the common types of Cucurbita
Pepo. Commercial material of this species is apt to be very much
hybridized and consequently to yield a remarkable variety of forms.
Many strains are also self-sterile, or become so after a year or two of
inbreeding. A considerable variety of types was obtained from
four leading seed firms in the spring of 1916, and an attempt was
made, by persistent self-fertilization, to establish from this highly
heterozygous material types which would be essentially pure. Of
course the majority of plants refused to set seed under these
conditions, but about twenty-five were found which were self-fertile,
and the offspring of these (except for a number of lines which have
since been lost through sterility) have been continuously inbred for
six generations. In most cases sterility disappeared by the fourth
generation, and by this time such a high degree of uniformity was
shown in all plant characters as to make it clear that a fairly close
approach to homozygosity had been attained. In 1919 a number
of crosses involving all the more notable character differences were
made among these various pure types, and the uniformity of the F,
in every case gave further assurance that the parent types were
approximately pure. An F, generation from each of these crosses
was made during the past season (1921).

95) [Botanical Gazette, vol. 74

96 BOTANICAL GAZETTE [SEPTEMBER

A number of the pedigrees involved rather radical shape differ-
ences in the original types crossed. Several pure strains of the ordi-
nary “scallop” or “pattypan” type were obtained (fig. 1) with
fruit essentially disclike in shape, being from two to four times as
broad as thick, with the teeth or scallops around the edge varying
in number, shape, and development. In one race of white discs
there appeared very early several plants in which the fruit differed
markedly from that of the disc parent, being nearly spherical in
shape, approximately as thick as broad, and with a rather weak
development of teeth. Intermediate forms did not appear, and the
spheres when inbred never produced any other shape. Several pure
lines with spherical fruits were thus obtained (fig. 1).

Cece ey Gl

A)ist. "SPHERE.

Fic. r

A single plant of one of these spherical-fruited lines was crossed
in 1919 with a plant from each of three disc-fruited lines. These
three lines differed somewhat in fruit shape, one having a relatively
flat disc and the others relatively deep ones, one being somewhat
flatter than the other. The F, generation in each case showed com-
plete dominance of the disc shape, and the type of disc (deep or flat)
was essentially like that of the particular disc parent used. In the
F, generation there was a sharp segregation into approximately
three-quarters disc and one-quarter sphere. It is evident that the
chief difference between these two shapes is caused by a single factor,
and that this shows complete dominance. F, counts for the three
pedigrees, together with the results expected on the single factor
hypothesis, are shown in table I.

The problem is not quite so simple as this, however, for the F,
segregates do not resemble exactly the original types, it being espe-
cially noticeable that the sphere segregates differ in shape, those

1922] SINNOTT—FRUIT SHAPE 97

coming from the crosses where the flattest disc was used being
noticeably flatter than those coming from the crosses where the -
thickest disc was used.

TABLE I
FRUIT SHAPE IN F, OF THREE CROSSES OF DISC XSPHERE
Pedigree Disc Sphere

es Ute Ge viene ott pee es fC 83 18
Dare ee ee et 79 29
EQ ura SE ek varus ee ness 41 13
otal) i) aa eee 203 60
PAPECHAMON. 350 ese. 197 66

To bring out more clearly the various shape differences, a study
of the relative sizes of the two major dimensions, width and length,
as represented by an index, is useful. This shape index for a given
fruit is its width (the dimension at right angles to the fruit axis)
divided by its length or thickness (dimension parallel to the fruit
axis). The means for the shape index of parents, the F,, and the two
extracted types in the F, for the three pedigrees, are set forth in
table II. The frequency distribution of the individuals in the three
pedigrees with respect to this shape index is also given in fig. 2.

TABLE Il
MEANS FOR FRUIT SHAPE INDEX (WIDTH+ LENGTH) IN THE FOUR PURE LINES STUDIED,
IN F', AND THE TWO TYPES SEGREGATING IN F2, FOR THE THREE PEDIGREES; FIG
PARENTHESES ARE INDICES EXPECTED ON BASIS OF TWO-FACTOR HYPOTHESIS

|
Disc SPHERE

103 (sphere) .| 0.97 |......
15 (disc)....) 2.48 | (2.47) 15...| 2.50 | (2.47) 15. ..| 2.51 | (2.47)| 0.86 | (0.97)
1 (disc)... .| 2.50 |(2.72)| 1...| 2.01 | (2.72) ..| 2.61 |(2.66)| 1.20 | (1.16)
19 (disc)... .| 3.28 | (3.22)] 19...| 3.34 | (3-22) o ..| 2.94 |(3-03)| 1.50 | (1.53)

Records for a comparatively small number of individuals of the
four pure types are here presented, since only a few plants are grown
of each of the various pure lines in any one year. The F, generations
were also small, but the F, generations were considerably larger.
Cultures involving much greater numbers are now being grown.

98 BOTANICAL GAZETTE [SEPTEMBER

From a study of these few individuals, however, certain points stand
out clearly. The F, shows complete dominance of the disc shape.
In fact, in every case the F, is even a little flatter than the parent
disc. This is notably the case in pedigree 1, but there is reason to
believe that the pure type of this line is probably a little flatter than
is shown by the individuals here portrayed.

In pedigree 15, which involves the deepest disc, both the sphere
and disc F, segregates are essentially like the original types, being a
little deeper in each case. A single factor difference between disc
and sphere is apparently sufficient to account for these facts. It will
be noted that there is a very sharp segregation between the two
shapes in the F,. In pedigree 19, however, which involves the
flattest disc, the F, spheres are decidedly flatter than the parent
sphere type (1.50 as compared with 0.97), and the F, discs distinctly
deeper than the parent disc type (2.94 as compared with 3.28).
Pedigree 1 is somewhat intermediate between these, the F, spheres
being somewhat flatter than the original sphere type, and the F,
discs being about the same as the original disc type, but consider-
ably deeper than the F, discs.

In pedigrees 19 and 1 there is evidently something more than a
single disc or ‘‘flattening” factor at work. This coincident flatten-
ing of the spheres and deepening of the discs may readily be ex-
plained by assuming that there is a second dominant flattening
factor, considerably weaker in its effect than the major one already
discussed, and segregating independently of it. The parent disc
type would possess both of these and the parent sphere type lack
them both. The major difference between disc and sphere would
still be caused by the larger factor, the ‘‘spheres” lacking it and the
“discs’’ possessing it. In the F,, however, three-quarters of the
spheres would possess the smaller flattening factor, and the average
shape of the whole sphere group would thus be flatter than that of
the pure type; and a quarter of the discs would lack this smaller
factor and thus be less flat than the original discs in which both
flattening factors are present. This would tend to bring the two
shape types somewhat nearer together in the F, than in the pure

types, a condition which evidently obtains in these two pedigrees.

1922] SINNOTT—FRUIT SHAPE

Peoicreel5

_ a

— 2 =

PepIcREE 1

PEDIGREE 19

= oo

60 120 1.0 A40 300 3.60 4.20

Fic. 2.—Fruit shape index (width/length) in parents, F, and F, of three pedigrees

100 BOTANICAL GAZETTE [SEPTEMBER

If we assume that the discs used in pedigree 15 differ from the
spheres by the possession of a single dominant flattening factor A,
which increases the index by 1.50, that in pedigree 19 the disc type
possesses in addition to this a second dominant flattening factor B,
which increases the index by 0.75, and that in pedigree 1 the sup-
plementary flattening factor (which we may call C) is smaller and
can increase the index by only 0.25, we would obtain approximately
the shapes which we actually find in the F,. The original sphere
type has an index of 0.97. The disc in pedigree 15 would thus have
an index of 0.97 plus 1.50, or 2.47, as compared with the 2.48 which
was found. The F, and F, types would be expected to repeat these
indices, a condition which they come reasonably close to doing.
In pedigree 19, however, the parent disc (AB) would have an index
of 0.97 plus 1.50 plus 0.75, or 3.22, as compared with the 3.28
observed. The F, should be approximately the same. In the F,
three-quarters of the spheres would be aB, 0.97 plus 0.75, and the
other quarter ab, 0.97 only, giving a mean for the whole sphere
group of 1.53. Similarly, three-quarters of the discs would be AB
or 3.22, and one-quarter Ad or 2.47, giving a mean for the disc group
of 3.03. These indices are close to the actual figures. The same
general situation would occur in pedigree 1, factor C being present
instead of A, and the original disc type being AC. In table II the
actual indices and the theoretical expectations are both presented.

It will be noted that this hypothesis does not explain the fact
that the F, discs are in every case flatter than the pure types. The
numbers involved are also much too small to prove such a hypoth-
esis. They certainly seem to indicate, however, that in two of
the disc types more than one factor is responsible for the shape dif-
ference between it and the sphere, and that these two factors are of
unequal effect.

This is probably a rather simple case of shape inheritance.
Indeed, other pedigrees at present in process of completion indicate
that shape inheritance in squashes is often much more complex,
involving a considerable number of factors, some of which also -
show lack of dominance. In GrortH’s' work with tomatoes, 4

* Grotu, B. H. A., Some results in size inheritance. N-.J. Agric. Exp. Sta. Bull.
278. pp. 92. pls. 34. 1915.

1922] SINNOTT—FRUIT SHAPE IOI

study of the F, in a number of crosses involving differences in fruit
shape shows that a distinct bimodal curve is present, thus suggesting
a segregation something like that here reported in squashes. In
many other shape crosses studied by this investigator, however, the
F, showed a wide range of shapes with no clear cut segregation of

LJ = Disc
MB = Spuere

or ee yO ae a a a NS 1 ee EO a8

LENGTH

YY
iS Wow Be tS lee RAN a0. Ab ab: 23 24 35

WIDTH

Fic. 3.—Length and width of F, fruits, pedigree 19

types, thus suggesting the operation of a larger number of factors.
EMERSON’s? work with squashes also shows a great increase in the
variability of shape in the F, and (apparently) no clear cut segrega-
tion. The parental types used by EMERSON, however, were not
inbred homozygous strains.

It is assumed that in the present case such things as “‘shape fac-
tors” exist in the germ plasm and are operative. It may be objected

* Emerson, R. A., The inheritance of sizes and shapes in plants. Amer. Nat,
44:739-746. IgIo.

102 BOTANICAL GAZETTE [SEPTEMBER

that the results are due merely to a segregation of those size
factors which control fruit thickness and fruit width. That
such an explanation is scarcely tenable, however, is indicated by a
study of the actual dimensions in the F., for here we find that the
squashes which are the longest (thickest) are also those which are
narrowest (thus producing the sphere types), and that the squashes
which are thinnest are also those which are widest (thus producing
the disc types). The frequency distribution of the actual lengths
and the actual widths of the F, fruits in pedigree 19 are set forth in
fig. 3. That part of each curve which consists of individuals which
are spherical in shape is shaded, the discs remaining white. In fruit
length there is evidently a fairly clear segregation into long and
short, but no segregation is apparent in width. It is noteworthy,
however, that the long fruits are not scattered irregularly through
the various widths, as would be the case if length and width segre-
gated independently, but that in practically all cases these long
fruits are considerably narrower than the average, and the short
fruits wider than the average, so that instead of a great variety of
types in two rather vague groups, two very distinct shapes result.

There is evidently something controlling the dimensional propor-
tions which the individual exhibits, and thus determining its shape.
The relation between these shape factors and those which control
size is a matter of considerable interest. The suggestion is perhaps
worth considering that the ordinary “‘size’”’ factors govern in some
way the total amount of growth attained, and that the shape factors
control the distribution and proportions of this growth.

Summary

1. Pure lines of summer squashes differing in fruit shape have
been isolated.

2. In crosses between a type with approximately sphericai fruits
and three different races having ‘‘scallop” or ‘‘disc”’ fruits, the disc
shape showed complete dominance in the F, in every case, and in the
F, there was a sharp segregation into three-quarters disc fruits and
one-quarter sphere. A single, large, dominant flattening factor
thus seems to distinguish these disc types from the spherical ones.

1922| SINNOTT—FRUIT SHAPE 103

3. In two of these crosses, the extracted spheres are distinctly
flatter than the pure types, and the extracted discs distinctly deeper
than the pure discs. This can be explained by assuming the opera-
tion, in each case, of a second flattening factor, also dominant, but
showing a much smaller effect than the first.

4. Evidence is brought forward that shape-determining factors
actually exist, and that the facts here set forth are not due merely
to the segregation of size factors.

CONNECTICUT AGRICULTURAL COLLEGE
STORRS, CONN

BIOCHEMISTRY OF PLANT DISEASES"
IV. PROXIMATE ANALYSIS OF PLUMS ROTTED BY
SCLEROTINIA CINEREA
J. J. Wittaman anv F. R. Davison
(WITH TWO FIGURES)

In the third paper of this series (6) the literature bearing on
the chemistry of plant diseases, especially the effect of disease on
the composition of plants and the chemical differences between
resistant and non-resistant varieties of the same species of plant,
was reviewed in some detail. Since the present work is a continua-
tion of the former, it will not be necessary to make reference again
to the results of other investigations, except incidentally during
the discussion.

In the previous work on the brown rot of plums, caused by the
fungus Sclerotinia cinerea, it was found that during the progress of
the rotting the H-ion concentration of the sap increases markedly;
that oxalic acid is produced, but hardly in sufficient quantity to
account for the increased acidity; that tannin decreases during
the rotting; that protein nitrogen increases, due probably to the
protein formed in the fungus mycelium. Resistant varieties did
not differ conspicuously from non-resistant varieties, so far as the
analyses showed, except that the resistant varieties usually had a
more acid sap, and that more oxalic acid was produced in them.
The tannin content of green plums usually increases after picking
from the tree, but infection by Sclerotinia entirely inhibits this
increase.

Experimentation

In the present work the ordinary proximate analyses, together
with the determination of calcium, were made, using four varieties
of plums at three stages of maturity, grown at the University Fruit

* Published with the approval of the Director as Paper no. 272, Journal Series,

Minnesota Agricultural Experiment Station. Presented at the meeting of the Ameri-
can Chemical Society, September 9, rg21.

Botanical Gazette, vol. 74] : [104

1922] WILLAMAN & DAVISON—PLANT DISEASES 105

Breeding Farm at Excelsior in 1918.2 In table I are given the data
concerning the samples.

PREPARATION OF MATERIAL.—The plums were halved or
quartered, freed from the pits, and placed in ovens at about go°-
95° C. until dry enough to grind. It was not thought necessary to
use special precautions in drying, considering the nature of the
analyses to be made. ‘The finely ground material was stored in
bottles. The plums were rotted by sterilizing in mercuric chloride
solution, and then inoculating with a suspension of spores by means

TABLE 7
DATA ON PLUM SAMPLES, 1918
| No. of
ao Texture
Lab. Vacs Abbrevi-| Date — Condition of ~ of
no. see ation | picked fruit cig rotted
growth for fruit
| rotting
Resistant
ee aad cae xX Wolf o BXWo| July 2 I Green, half grown 9 Firm
2 urbank X Wolf 9 BXWo | Aug. 21 It Fully grown, not ripe 12 Firm
6h Be rbank X Wolf 9 BXWo | Sept. 3 | II Ripe 10 —
rm
80...) Abundance XWolf 18 |AXW 18] July 2 I Green, half grown 12 Firm
88...) Abundance X Wolf 3 AXW 18} Aug. 21 II Fully grown, not ripe 9 Hard
pig Abundance Wolf 18 |AXW 18} Sept. 3 | III Ripe II Firm
fy
81...| Compass Cc July 2 I Green, half grown 6 ft
89...| Compass C Aug. 2 II Fully grown, not ripe 7 Soft and
wat
93...| Compass Cc Aug. 8] III Ripe 6 ft
82...| Sand cherry XFormosa| SCXF | July 2 Green, half grown 6 — ;
what soit
90...) Sand cherry XF — SCXF | Aug. 2 II Fully grown, not ripe 7 ft
94...) Sand cherry XFormosa| SCXF | Aug. 8 | III Ripe 6

of a hypodermic syringe, plunging the needle right to the pit.
It required from eight to fourteen days for complete rotting, as
shown by the tissue becoming dark brown throughout.

METHODS OF ANALYSIS.—The moisture content of each sample
was carefully determined at the time the other analyses were made,
by drying to constant weight in a vacuum at 60°C. For the ash
determination, 2 gm. samples were incinerated in platinum dishes,
and then heated in a muffle at 550°C. until constant in weight.
The calcium was determined in the ash by the McCRuppEN method
(3), which has proved to be very simple and accurate. The Official
Methods (1) were followed for total nitrogen and ether extract,

? The writers’ thanks are due to Dr. M. J. Dorsey for his courtesies in furhishing
€ samples.

106 BOTANICAL GAZETTE [SEPTEMBER

T ASS
% ,
FO}
40 "
: : H
' ’ 5
3O0r i : a
H : H
al : a :
me MITROGEN
20h
‘ H
' ‘ '
rs ee Lae a : H
1 ' 1 ' ' '
' ; : : | ‘ s
ite as | 8: H AL
rai cao
ao}
' ‘
rit
lt H
mie is :
4 '
i eae | iE
tug FFHED\F POAT
80
60L
4Or
H
: H
2or. of
ete : : H
HET EL
ao 5 : <_: 2 s
265 205 CRUDE, FIBER
15.0
'
“Mor 1
a ; '
t 4 5
vols |e ' ' H
: ; ‘ : . ‘
tee re H : ake .
ue Ce wee ee a an ior de 2 ae eee
Bxrws AkW /8 Compass SCOXF

Fic. 1—Composition of sound and of rotted plums of various varieties at three
stages of growth: solid line, sound samples; dotted line, rotted samples; see table
for stages of growth and names of varieties.

1922]

and the KENNEDY (2) modifica-
tion of the SWEENEY method
was used for crude fiber.

Results

The data obtained in these
analyses are shown graphically in
figs.1 and 2. All values are cal-
culated to a moisture free basis.
In fig. 1 the sound and rotted por-
tions of each sample are placed
side by side, so as to show the
change in composition during
rotting. It will be seen that in
almost all cases the rotted portion
shows a higher content of all con-
stituents except crude fiber; the
latter shows no general tendency
in either direction, sometimes
being greater and sometimes less
in the rotted than in the sound
material. The increase in these
constituents is probably due to
loss of dry matter through res-
piration. Previous work has
shown that respiration is higher
in infected than in sound plums,
and this results in a relative in-
crease in the substances deter-
mined. The figures for ether
extract and for crude fiber are
erratic in their changes, which is
in keeping with the empirical
nature of the methods of analysis.

In fig. 2 the same data are
used, but they are arranged so as
to give more direct comparison of
varietal characteristics. The first

WILLAMAN & DAVISON—PLANT DISEASES

107
ASH
%o
so}
40
Tl |
oe NITROGEN
20 :
7 i
ef
ull
“ov O
go} :
es
ie
2 | i
, ts
La]
ss
.;
be ETHER EXTRACT
6.0}
40}
H
20} ae pes
22 5s
aes
ee
RUDE FIBER
265 205
/50}
HOr
;
70} .s
tt
LEE
30 c dabig WOK) IW CS
yy. IT He

fstashee of sound and of

rotted pls grouped to bring out varietal
: solid line, sound sa

dotted ‘line, rotted samples; first two vari-

rot; second two are susceptible; s
for stages of growth and names ie varias.

108 BOTANICAL GAZETTE [SEPTEMBER

two varieties in each section, indicated by 9 and 18, are resistant;
the next two are non-resistant. Some of the rotted samples are
missing, due to loss by contamination. It will be seen that the
crude fiber is markedly higher in the resistant than in the non-
resistant varieties, but all other constituents are lower. This
relation holds in both the sound and the rotted samples, although
data for the latter are available for the first stage only. VALLEAU
(4) reports a positive correlation between firmness of the plum
flesh and its resistance to brown rot. The firmness is due to the
structural elements of the tissue, the cellulose cell walls and the
pectic middle lamellae. Only the former are represented in the
determination of crude fiber. From the results at hand it appears
quite probable that the quality and quantity of cellulose material
are important factors in resistance properties, although the pectic
substances also play a part in the metabolism of this fungus, as was
pointed out in a previous paper of this series (5). In what ways the
middle lamella may play a part in resistance properties is not
known. Since it is a compound of pectin with calcium, it was
thought that determinations of calcium in the present samples
might throw some light on the question, but the data show that
calcium is higher in the susceptible varieties in about the same
magnitude as the ash and nitrogen, and no special significance can
be seen in it.

In fig. 2 can be seen certain changes in the composition of plums
during the course of ripening. As maturation progresses, the ash,
nitrogen, and calcium steadily decrease. This is probably due to
large increases in the soluble carbohydrates and organic acids.
The crude fiber is somewhat higher in the second stage, which is
just previous to full ripeness. The Compass variety is conspicu-
ously low in crude fiber, and it is very susceptible to rotting by
Sclerotinia. In table I the data on rate of rotting show the same
tendencies as were discussed in the preceding paper of this series,
namely, that the resistant varieties succumb to the rot much more
slowly, and when rotted have a much firmer texture than the
susceptible varieties.

Conclusions

1. Plum tissue that has been rotted by Sclerotinia cinerea is

consistently higher in ash, CaO, nitrogen, and ether extract than

1922] WILLAMAN & DAVISON—PLANT DISEASES 109

is the sound tissue. This is no doubt due to loss of dry matter by
respiration in the rotted samples.

2. The resistant varieties are conspicuously higher in crude
fiber than the susceptible. The quality and quantity of the
structural elements of the tissues no doubt are important factors
in their resistance properties. The ash, nitrogen, CaO, and ether
extract are lower in the resistant varieties, but not sufficiently so
to constitute limiting factors in the nutrition of the invading
parasite.

3. As the ripening of plums proceeds, there is a decrease in the
ash, nitrogen, and calcium content, due probably to storage of
carbohydrates and acids,

DIVISION OF AGRICULTURAL BIOCHEMISTRY

MINNESOTA AGRICULTURAL EXPERIMENT STATION
St. PAu.

LITERATURE CITED

1. Association of Official Agricultural Chemists. Methods of Analysis.
Baltimore. 1916.

. Kennepy, C., A capecagiuanes of = i oa method for crude fiber.
Jour. Ind. and Eng. Chem.

3- MitcHett, J. H., Report on nor lant constituents. Jour. Ass.
Official Agric. Chemists 42391-3904.

4. VALLEAU, W. D., Varietal ae : ane to brown rot. Jour. Agric.
Res. 5: 365-395. 1915.

5. WiLiaMAN, J. J., Pectin relations of Sclerotinia cinerea. Bor. GAz. 70:
221-229. 1920.

6. WILLAMAN, J. J., and Sanpstrom, W. M., Biochemistry of plant diseases.

J
III. Effect of the fungus Sclerotinia cinerea on plums. Bor. Gaz. 73:287-
307. figs. 7. 1922.

“MAGNESIA INJURY” OF PLANTS GROWN IN
NUTRIENT SOLUTIONS
W. F. GERICKE

Among the first signs of injury to the tops of wheat seedlings and
other cereals grown in nutrient solutions of relatively high (as com-
pared with other salts in solution) concentration of MgSO,, one of
the three or more salts commonly used in culture solution experi-
mentation, is that resulting in abscission of the leaf tips of the
plants. The progression of this injury consists of wilting, wither-
ing, desiccation, and finally abscission. This injury has been
found to be most pronounced on young shoots. It also occurs in
a much greater degree under conditions conducive for high tran-
spiration of the plants than forlow. The term ‘magnesia injury’’
has been applied to this peculiar phenomenon of abscission of leaf tips,
being so named because usually found associated with comparatively
high concentrations of magnesium ion (from MgSO,) in nutrient
solutions. Additions of soluble calcium salts to nutrient solutions
giving injury were often found to be beneficial. This lent support
to the concept that a certain calcium-magnesium ratio, or a range
thereof, plays an important part in the physiological balance of
nutrient solutions.

Recent experiments by the writer appear to bear on this mag-
nesium question. When wheat seedlings were grown in single
salt solutions it was found that some cultures gave the typical
symptoms and others did not. Briefly, the tests were as follows.
Seedlings 6-8 cm. high, with roots 8-10 cm. long, were fitted
into and supported on paraffined corks. These were fitted into
one quart containers (Mason jars) filled with the single salt solu-
tions to be tested. The solutions were prepared from Baker’s
C.P. analyzed salts and distilled water. The salts were tested to
see whether they conformed to specifications, but no further
purification was made. A small amount of FeSO, (5 drops of 0.01
mol solution) was added to the cultures at weekly intervals. The
Botanical Gazette, vol. 74] : [x10

1922] GERICKE—MAGNESIA INJURY Iil

cultures were allowed to grow four weeks. Table I gives the
experimental data.

The injury sustained by the seedlings grown in the solutions of
potassium salts differed with the salts used, being least in the
KH,PO, set and most marked in that of K,SO,. Considerable
abscission of the leaf tips occurred in the seedlings grown in the
solutions of KNO,, although these cultures made by far the best
growth (total dry matter production) of any of the nine different
salt solutions employed. In marked contrast to these are the
results obtained from the cultures grown in the solutions of different
calcium salts, none of which gave any symptoms of the character-
istic injury. Of the cultures grown in the solutions of magnesium

TABLE I
RELATIVE EFFECTS OF SALTS IN PRODUCING ABSCISSION OF LEAF TIPS OF WHEAT
SEEDLINGS

Salts goncentrty | Pu Value Injury
ey ie cae a 0.01 6.3 Decided

re i eae 0.01 5.2 Slight (some plants showing none)
poe Pea oe eee ha 0.01 7.4 Excessive

CeO as ey 0.01 eee N
CaHPO, and Ca(H,PO,),.. .|Saturated 5.0 None

0.002

Mb cla a eles Gk sa 0.01 6.7 None
WAMUING ee i es 0.01 ‘3 Excessive

rd 6 i 8 pee Ie Ea bie 0-01 eB None

Bi a eis Gs cee 0.01 6.0 Excessive

salts, those grown in Mg(NO,),. and MgSO, were severely injured,
but those grown in MgHPO, were not, being perfectly normal in
this respect. While the P,, values of solutions were not the same,
nevertheless it is not evident that this was an important factor to
account for the results.

The injury of abscission to the leaf tips of the cultures grown
in the solutions of potassium salts appeared to be similar in every
respect to that of the cultures grown in solutions of Mg(NO,),

tr MgSO,. Whether it was physiologically the same cannot be
stated at this time. If the injury to these seedlings was physio-
logically the same, it appears that there are at least two factors
apparent in the data that are related to this injury of abscission
of leaf tips, as follows:

II2 BOTANICAL GAZETTE [SEPTEMBER

1. The lack of or the deficiency of calcium in the nutrient media,
It is in this sense that the injury to the seedlings grown in the
solutions of potassium salts is to be accounted for, as it was obvi-
ously not due to the presence of magnesium. Furthermore, as
the cultures grown in the different solutions of calcium salts were
not injured, this is suggestive that beneficial results should obtain
from additions of calcium salts to nutrient solutions that have
shown themselves to be poor media for plant growth because of
excessive amounts of potassium or magnesium salts. Numerous
tests have proved this to be true. This, however, does not neces-
sarily imply any definite calcium-magnesium ratio or a calcium-
potassium ratio as a condition of physiological importance in
nutrient solutions. The amount of calcium ions needed to over-
come the harmful effects of excessive concentrations of potassium
ions or magnesium ions will be determined largely by other condi-_
tions or sets of conditions under which the plants grow, of which
those affecting the rate of transpiration of the plants are not
of least importance.

2. The relation of phosphorus. A relatively high concentra-
tion of magnesium ion and the absence of calcium (except a trace
as an impurity) in the solutions are conditions supposed to be
conducive to injury. As no abscission of the leaf tips appeared
in the seedlings grown in solutions of MgHPO,, it appears that in
the magnesium-phosphorus relation is a condition that in this case
is physiologically important. It is hardly possible that the trace
of calcium found in MgHPO, could account for these results.
Equally large traces of calcium were found in the other salts used,
especially K.SO,, which contained 0.005 per cent. As this amount
did not prevent injury, it seems reasonable to discount the effect
of a smaller trace of calcium found in MgHPO, as being the cause
for the non-injury to the seedlings. The fact that KH,PO, pro-
duced less injury than did any of the other potassium salts used
presumably was due to some action involving the H,PO, ion.

As the potassium salts and two of the magnesium salts used
gave injury to the wheat seedlings, one can infer that this was due
to some action of a positive ion of the salts in solution. On the
other hand, certain positive ions, calcium for example, did not

1922] GERICKE—MAGNESIA INJURY 113

produce injury. It does, as has been shown in other experiments,
prevent injury where magnesium ions are excessive. The harmful
effect of some of the positive ions, however, can also be prevented
or greatly mitigated by the presence of certain negative ions. The
phosphate ion comes in this category in the cases of the MgHPO,
and KH.PO, in this experiment, the former salt producing no
injury and the latter salt only a little. Under certain conditions,
therefore, it may be expected that additions of phosphate salts
should prove beneficial to nutrient solutions that are toxic due to
excessive concentrations of either magnesium or potassium. This
the writer has found to be the case in other experiments.

No reference has been made to the literature, as this is to be
taken up later when the subject will be discussed in greater detail.

UNIVERSITY OF CALIFORNIA

CURRENT LITERATURE

BOOK REVIEWS
Morphology and cytology of fungi

DeBary’s great treatise, indispensable as it still is to the working mycolo-
gist, has become in many respects so obsolete as to be not only unsatisfactory
but even misleading in the hands of less advanced students of the fungi, and a
modern, authoritative work in the English language, with the same compre-
hensive scope, is greatly to be desired. The volume by Dame GWyYNNE-
VavuGHAN' in large measure meets this need, so far as the groups of which it
treats are concerned. Presumably another volume in the same series is forth-
coming, which will complete the account.

The first part of the book, occupying thirty-four pages, is devoted to
general introductory matter, applicable to the fungi as a whole. It contains

the last-named term used in a narrowly restrictive sense to apply only to
lichens and mycorhizas. The remainder of the book is devoted to a detailed
shee by subdivisions of the particular groups specified in the title.
n the matter of systematic treatment the author has been commendably
Ba EA: for the most part, but she has not hesitated to make radical
rearrangement of the currently accepted systems where the need has existed.
This is strikingly shown in the treatment of the Ascomycetes. The ‘great
”” Ascomycetes is divided into three “groups” (why not classes and

Plectascales. The latter order is expanded to include everything from the
Endomycetaceae and the yeasts to the Terfeziaceae. The result is an arrange-
ment simpler and more usable than that of ENGLER, which at the same time
does no violence to our present admittedly very imperfect knowledge of the
relationships among these primitive forms. Furthermore, it is a pleasure
to see in a modern book a reversion to the earlier conception of the Archimycetes,
the Oomycetes, and the Zygomycetes as three coordinate groups of the Phyco-
mycetes, rather than an adherence to the more recent but less logical practice
of placing all the lower Phycomycetes in the Oomycetes

t GWYNNE-VAUGHAN, Dame HELEN, Fungi. Ascomycetes, Ustilaginales, Uredi-
nales. Cambridge Botanical Handbooks. pp. xi+232. figs. 196. Cambridge. 1922.

114

1922] CURRENT LITERATURE II5

The general discussion of each subclass is followed by a key to its orders,
‘and of each order by a key to its families. These keys are clear and simple,
and add greatly to the value of the book. After each special topic, or discussion
of a family, a bibliography is appended, in which the selection of the titles has
been dictated by matured judgment. The illustrations are numerous and
appropriate. Many of them are crudely drawn, which detracts greatly from
the appearance of the book, but they are always clear and accurate. Muc
consideration is given to the cytological aspect, which in view of the research
interests of the author is not surprising. The frequency with which she
emphasizes the points in need of further cytological investigation should prove
stimulating to workers in this fie

he implication on page 4 » Chat we must accept two nuclear fusions as the
normal situation in all ounede will be regarded by many mycologists
as premature. The entire subject must be carefully reinvestigated in the light
of recent parallel studies on the Basidiomycetes before this can be regarded
as definitely established. In this connection, the reference to clamp connections

food (p. 1), and as merely vegetative phenomena (p ; ave to be
revised. Again, the statement that “in Puccinia, Phragmidium, and other
Uredinales . . . . the basidia are developed in chains” seems to stress unduly

the seinlosiead: conception of the basidium, just as the thought of each cell
of the promycelium as a one-spored basidium, as held by other botanists, seems
to place undue emphasis on morphological detail. Lacking more convincing
evidence than has yet been presented, it would seem better to retain the inter-
mediate and generally accepted view that the teleutospore cell is not a basidium,
but is the cell that gives rise to one, either externally, as a promycelium, or
internally. In fact, the author is not consistent in her treatment, and seems to
recognize the latter view on the same pages on which she gives different inter-
pretations.

The proofreading has been carefully done and typographical errors are
few. Fig. 27e is a transverse, not a longitudinal section, and a few words,
mainly proper names, are misspelled, all of very minor importance. The
author is to be congratulated on the effective presentation of a mass of informa-
tion which has heretofore Rech: scattered and largely morenirimesies to the majority
of the workers in this field. an collating
this work and in presenting it so clearly and concisely. The book is a necessity
for the reference shelf of every laboratory where mycology is taught.—G. W.
Martin.

Lichens
_ Miss Annte L. Suiru,? of the British Museum, is the author of a notable
work on lichens, in which are considered the history of lichenology, the morphol-

?Smiru, ANNIE L., Lichens. 8vo. pp. xxviit+464. figs. 165. Cambridge Uni-
versity Press, England. 1921.

116 BOTANICAL GAZETTE [SEPTEMBER

ogy of the lichen thallus, reproduction in lichens, and the physiology, bionomics,
phylogeny, taxonomy, ecology, and economics of lichens.
he history of lichenology is treated in seven chapters, six of which follow
KREMPELHUBER in the first volume of his Geschichte und Litteratur der Lichen-
ologie. The seventh period extends from 1867 to the present time. Very
~ little space is devoted to the first six periods, as much of the work of these
was based on a wholly wrong conception of lichens, and the systematic
eat was largely very poor. In 1867 and the following year DEBARY
and SCHWENDENER established the sock that what had been considered con-
stituent parts of lichens were “ee with which the lichens were growing in
symbiotic relationship, and made modern lichenology possible. For the six
periods, those especially tunities can refer to KREMPELHUBER’S extended
treatment; but it would seem that the seventh period, which covers all of
modern lichenology, might well have received more space.

Preceding the discussion of morphology proper is a chapter in which the
algal host cells are treated as constituents of the lichen, under the term
“‘gonidia,” which designation, according to the belief of many botanists, should
have been consigned to oblivion long since. The treatment of the relationship
between the lichen and its algal host contains much information that is valuable,
but unfortunately it is all based on the supposition that the lichen is a com-
posite structure, a fungus and many individual algae, and still in some mysteri-
ous way a plant. It is the belief of a constantly increasing number of American
botanists that such a confusing presentation should never be placed before
the student or the botanist.

In the treatment of types of thalli, structures peculiar to lichens, cells and
cell products, general nutrition, assimilation and respiration, illumination,
and color, the chapters on morphology and physiology carry much that is
valuable. All is colored by a phraseology which is confusing to those who
believe that lichens are fungi, however, and indeed scarcely comprehensible
to them, excepting a few of the older ones, who, like the reviewer, were taught
to believe that the lichen should be considered both a colony and an indi-
vidual.

The chapter on reproduction on the whole is SSE and is perhaps the
most up-to-date and valuable portion of the volum he discussion takes
form under such topics as types of fruits, aaa of reproductive organs,
apogamous reproduction, stages of apothecial development, and spores an
asci. The treatment of forms of reproductive organs in lichens is the first
adequate presentation to appear in a text. For those of us who believe that
lichens are fungi which should be treated like other fungi, and that carpologic
development and structure should play a large part in taxonomic disposition,
this chapter brings our data together in convenient form so far as lichens are
concerned. Unfortunately, the discussion of the matter in other Ascomycetes
is given separately toward the close of the chapter.

1922] CURRENT LITERATURE

Rather closely related to the consideration of reproduction stands that of
phylogeny in another chapter. This opens with a presentation regarding the
algal hosts, which many would omit from a consideration of the phylogeny
of lichens. Following this is a valuable treatment of the relationships between
lichens and other fungi from the standpoint of evolution. The evolution of
the thallus is considered next, then that of the various groups of lichens. The
chapter closes with a ‘scheme of suggested progression in lichen structure.”

e chapter on taxonomy considers first the various schemes of arrange-
ment, following which the lichens are arranged according to the system of
ZAHLBRUCKNER, as given in ENGLER and PrantL. Then follow treatments
of number and distribution of lichens, with a survey of the lichens of polar an
temperate regions, and fossil lichens. Probably ZAHLBRUCKNER would modify
the classification outlined fifteen years ago considerably, were he to give his
present views; but it is readily conceded that no lichenist, save perhaps
Warn10, has shown so much skill and knowledge in the classification of lichens.
For one who believes that lichens are dual organisms, there is no other possi-
bility than to consider them a distinct group of plants, as is done in the volume
before us. Also, as a matter of expediency, lichens may be treated separately
by those who believe that they are fungi, although at the expense of failing to
present adequately the many close relationships between lichens and other
fungi. In any flora which covers all fungi, distribution should be made some-
what as is done in papers by the reviewer and several other American bot-
anists.

The chapter on bionomics contains a valuable discussion of the growth and
duration of lichens, the season of fruit formation, dispersal and increase,
parasitism, and the diseases of lichens. Closely related to this is the chapter

n ecology, which brings together for the first time a considerable portion of
the material which deals with this subject. Although the research on lichen
ecology is mainly pioneer work and much of it faulty, the worker in this phase
of ecology must refer to the chapter, which will be bewildering to many who
have concluded that lichens are fungi.

ile SCHWENDENER and other Europeans have held that lichens are
fungi, they have not been able to treat lichens as fungi after the method of
mycology in general. This has been left to America, where the more rational
treatment of these plants began to take form a generation ago and is now
taught in a considerable number of institutions and believed by many teachers
and other botanists. The reviewer does not relish attacking the conception
of lichens held by the author of a work of great merit. The issue is unavoidable,
however, and although American botanists may get much of value from the
volume, it is to be hoped that students will not be taught that lichens are not
plants, but yet in some mysterious way are plants, and that maturer botanists
may be able to get that which is valuable from the work and not fall into the
confusing phraseology regarding the nature of lichens.—Bruce FINK.

118 BOTANICAL GAZETTE [SEPTEMBER

NOTES FOR STUDENTS
Veevudien of British Guiana.—Hircucock; has given an_ interesting
sketch of the conditions of plant life in British Guiana, with notes on the
flora. The climate shows great uniformity of temperature, the mean maximum
having the narrow variation of 83° to 87° F., and the mean minimum from
74.5° to 76.5°F. The annual rainfall ranges from 150 inches in the north to
50 inches in the south, with a relatively dry period extending from August to
November. Virgin forest covers the greater part of the country, showing
many of the characteristics of tropical rain forest, such as stratification, abun-
dance of lianas, buttressed trunks for the larger trees, and great luxuriance.
Attention is directed to cleanness of the forest floor due to the destruction of
fallen trees and branches by decay and by wood ants. This condition is also
accentuated by the scanty growth of low vegetation due to the density and
uniformity of the shade. Species of the forest trees are not gregarious, but
are scattered here and there.
he flora shows some interesting comparisons with that of the United

species, as Fagaceae, Cruciferae, Ranunculaceae, Rosaceae, Labiatae,
Umbelliferae, and Compositae. Some familiar families are found in Guiana
chiefly as trees, as Euphorbiaceae and Solanaceae. On the other hand, certain
families sparsely represented in the United States are found in greatly increased

mbers. otable among these are the Araceae, Palmaceae, Piperaceae,
Rubiaceae, Myrtaceae, Lauraceae, Sapotaceae, and Melastomaceae. Orchids
reach their highest development on the mountains.—Gro. D. FULLER.

Soil moisture.—As a result of recent investigations, PARKER‘ presents
evidence that the vapor pressure of different moisture contents, the equilibrium
relations with seeds, and the freezing point depression due to solid material
do not indicate different forms of soil water such as given by the dilatometer
method. This would indicate that the old method of classifying soil moisture
as hygroscopic, capillary, and gravitational, although open to certain objections,
still remains the best available. The opposing view, presented by Bouyoucos,
has already been noted in this journal.’ ParkER’s experiments, however,
tend to support the views of such modern othe as RussELL and KEEN
that all the water present in the soil is subjected to the same law over the whole
experimental range, and the various constant and critical points shown by
soils at varying degrees of water content are equilibrium values only, and
do not indicate any break or abrupt change in the physical condition of the
soil moisture.

3 Hircucock, A. S., Floral aspects of British Guiana. Ann. Rept. Smithsonian
— pa cathe Lg 293-305. pls. 12. 1921.
F. W., The classification of soil moisture. Soil Science 13:43-54- 1922-
5 Ah Bi 733420. 1922.

1922] CURRENT LITERATURE 119g

In this and in a previous paper,® PARKER holds that the freezing point
depression for the moisture equivalent and probably also for the wilting
coefficient is practically a constant for all soils. This may be taken as addi-
tional evidence that the moisture equivalent and wilting coefficient are within
very considerable limits constants for all soils——Gro. D. FULLER.

Physicochemical problems relating to soil.—Under this title? the Faraday
Society has brought together in book form the papers ‘presented before the
Society during the general discussion of this topic at its meeting in London
on May 31, 1921. The discussion is divided into five sections, and was
planned to form a rather complete survey of the subject. The first section
is general in nature, and consists of a survey of the whole field by RussELL,
and a discussion of the physical properties of soils in relation to survey work
by Roxsinson. The second section deals with the problems of soil moisture,
with papers by KEEN, OpEN, HOAGLAND, SHULL, and Hackett. The third
section considers the organic constituents of the soil, with papers by Pace,
OpEN, and Satispury. The last two sections are concerned with colloidal
properties, the adsorption phenomena of section four being discussed by
FiscHER, CROWTHER, and Morrison. The final section deals with the
dispersity, flocculation, and plasticity of clays by ODEN, ComMBER, and MELLor.

The discussion as a whole forms an important addition to soil literature,
and one is impressed by the usefulness of such symposia as the Faraday Society
has organized from time to time. The custom of holding such general discus-
sions devoted to an entire survey of some field of investigation is one that might
well be established among scientific societies in this country to replace the
less valuable type of symposium now in vogue here.—C. A. SHULL.

Photosynthesis control in forest plants.—In investigating the conditions
affecting photosynthesis in forest undergrowth, LUNDEGARDH’ using a new
form of assimilation-chamber, found that with variations of carbon dioxide
concentration and low light intensities both the light and the carbon dioxide
supply are controlling factors. The advantages from a supply of carbon
dioxide above normal appear most strongly in low intensities of light. For
Oxalis acetosella at 0.025 of sunlight, and for Viola tricolor at 0.25, an approxi-
mately direct proportionality was obtained between the carbon dioxide concen-
tration and the intensity of photosynthesis. In the forest, on account of the
production of the CO, by the ground, the air (especially that nearest the
ground) becomes rich, the CO, content often rising to more than twice normal.
This increase, least over sandy soil and greatest over the humus of beech woods,

ARKER, F. W., Methods of ee the concentration and composition of
the soil solution. Soil Science 12: Seedes 32.
7 Physicock I ting to the soil. Trans. Faraday Soc. 17: 217-368.

1922,
* LUNDEGARDH, HENDRIK, Ecological studies in the assimilation of certain forest
plants and shore plants. Svensk, Bot. Tidsk. 15:46-95. figs. 9. 1921

120 BOTANICAL GAZETTE [SEPTEMBER

is an important condition for the existence of shade flora. In such plants,
in order that the daily products of photosynthesis may compensate the respira-
tion of darkness, there is required at 18° C. an average illumination of little
more than o.o1 light; and in order that growth may be maintained, in the case
of Oxalis, a minimum daily illumination of 0.25 light for somewhat more than an
hour. In sun plants an equilibrium between respiration and photosynthesis
is reached at about 0.025 light—Gro. D. FULLER.

Prothallia from sex organs of Polypodium.—SrTe1L’ has reported that “in
an old culture of Polypodium irioides the sterile cells of a large number of
antheridia and archegonia became vegetative like ordinary prothallial cells.’
No case of regeneration from the sex organs of a pteridophyte has been reported
previously. The cap cell and ring cells of the antheridia produced prothallial
filaments and secondary antheridia; while the cells of neck and venter of the
archegonia also prodpted Poreoe ta and antheridia, but in no case secondary
archegonia. Th n this way reached maturity, developing
actively motile sperms. ‘It was impossible to state under what cultural con-
ditions the cells of the sex organs regenerated, but it is suggested that the
peculiar behavior was . result of unfavorable conditions which appeared in
the old culture-——J. M

Oxalophytes over limestone.—Recent studies by SaLisBuRY and TANSLEY”
have shown that Quercus sessiliflora, regarded as a decided oxalophyte, occurs
in the regions under consideration over limestones. Analyses, however, prove
that leaching has so reduced the lime content of the surface soils that they are
often really acid in their reactions, and hence the oak seedlings and the accom-
panying calcifugous herbaceous vegetation really develop in a non-calcareous
or even in an acid soil. This adds another to the rapidly accumulating array
of facts indicating how dangerous it is to assume that calcareous rocks always
give rise to calcareous soils.—Gro. D. FULLER.

Stock-poisoning plants—LAwrENCE™ has published an account of the
principal stock-poisoning plants of Oregon for the use of ‘‘the Oregon farmer or
stockman.”’ The statement is made that ‘‘the annual toll of the poisonous
plants in Oregon is surprisingly heavy.” It is of interest to botanists to note
that the principal poisonous plants of Oregon are Delphinium (6 spp-),
Zygadenus (2 ni Cicuta ° spp.), Lupinus (x sp.), Astragalus (1 sp.), and
Pteridium (1 sp.)—J. M. C

9Stem, W. N., The development of prothallia and antheridia from the sex
organs of Polypodium irioides. Bull. Torr. Bot. Club 48:271-277. figs. 4. 1921-

3 ury, E. J., and Tanstey, A. G., The Durmast oak-woods (Quercela
sessiliflorae) of the Silurian and Malvernian strata near Malvern. Jour. Ecol. 9:19-38-
pl. I.. 1921.

™ LAWRENCE, W. E., The principal stock-poisoning plants of Oregon. Oregon
Agric. Coll. Exper. Sta. Bull. 187. pp. 42. pls. 2. figs. 10. 1922

VOLUME LXXIV NUMBER 2

THE

BOTANICAL GAZETTE

October 1922

HETEROTHECA GRIEVII THE MICROSPORANGE
OF HETERANGIUM GRIEVII

MARGARET BENSON

(WITH PLATES 1V, V, AND EIGHT FIGURES)

Introduction

The sporangia here described have so far only been recorded
from the Pettycur deposits of the Calciferous Sandstone Series of
Scotland. They have been found in three blocks, one of which,
presented to the writer by Professor BAYLEY BALFouR in 1905,
yielded also some of the specimens of Sphaerostoma of which a
description has already been published (5); the other two blocks
were collected at Pettycur by the writer in 1910. In all three
blocks they were found associated with Heterangium Grievii.
Their somewhat flattened fusiform shape is approximately that of
Telangium Scottii (4), but the dimensions are less. T. Scotti
measures about 23mm. in width at its maximum girth and
4mm. in length, whereas the new sporange only measures roughly
1X2 mm. in width and 3.5-4mm. in length. -A further resemblance
to Telangium is their possession of longitudinal loculi or series of
loculi, and of peripherally placed tracheids. These resemblances
do not seem adequate to suggest its inclusion in this form genus,
because there are many remarkably distinctive characters in the
new form.

In the first place, each peripheral loculus of Telangium is
represented in Heterotheca by a series of relatively small loculi.

121

T22 BOTANICAL GAZETTE [OCTOBER

Secondly, central loculi as well as peripheral ones occur in the new
form. A third outstanding difference is the absence of any evidence
that the sporange underwent apical dehiscence, which is almost
universally the case in species of Telangium, whether Lower Carbon-
iferous (for example, 7. affine) or Upper Carboniferous (for example,
T. Scottii, etc.). The only exception known to me is a species*
described by Natuorst (11). A fourth outstanding difference
from Telangium Scottii (the only species so far described with struc-
ture preserved) is the presence in the new form of water storage
tracheids, which, although few in the normal specimens, are very
abundant in the partially sterile specimens. Lastly, a character
is found which at first sight seems of minor importance. The new
sporange retains the twofold cortical sclerotic plates which form
so characteristic a feature of the cortex of Heterangium stem and
petiole. It is this latter feature which the writer regards as irrefu-
table evidence of the safe attribution of these microsporangia to
Heterangium Grievii, with which they have invariably been found
associated. Although, therefore, the sporange has the same claim
to the name of the parent plant as either stem or petiole, it has
been found convenient to refer to it under the name of Heterotheca
Grievii.

Diacnosis.—I have founded the form genus Heterotheca for
the reception of such microsporangia as resemble Telangium in
form and possibly in insertion, but possess vertical sclerotic plates
in their periphery and horizontal sclerotic plates deeper down in
the cortex, like the vegetative organs of Heterangium Grievit. The
loculi are not confined to the periphery, but central ones also occur.

The specific name of the form now described is that of the
parent plant.

Form, anatomical structure, and grouping of specimens

Form.—The form of the sporange can be deduced from the
various series of sections through single specimens. Some of these
have been plotted out to scale in text figs. r and 2. These show

* This species, of which sd type saseacene was edie by ARBER (1) under the name
of Carpolithus Nathorstii, ma of Telangium, owing to NATHORST ’S
discovery of its longitudinal loculi filled with micro spores. The plate referred to
exhibits what was possibly approximately the habit of Heterotheca Grievii.

1922] BENSON—HETEROTHECA GRIEVII 123

H. Grievii to have had a tapering apex and a maximum girth nearer
the base than the apex. The majority of the transverse sections
through the upper part are circular, but in the basal region the
sectional area is oval (figs. 8, 9), hence there are two aspects of
each sporange given in text figs. 1 and 2.

In longitudinal sections the apical part is seen in surface view
if present, as indicated in text fig. 3. Inthe upper third, the surface
loculi are only slightly rubbed down in the center, the lateral ones
being seen almost in surface view. If two sections are secured

< Plane of 383.10
Plane of 387.12
D° of 383.1!
Bot 383 D of 387.11
: of 3831 of 387.
‘ :

Fic. 1 : Fic. 2

Fics. 1, 2.—Showing slightly bifacial form of sporange as indicated by plotting
series of transverse sections to scale on vertical line; fifth section in series (CN . 383. 14)
just included five separated bases of loculi series, a fact on which the length (4 mm.)
i ced.

longitudinally through a single sporange, they are both somewhat
peripheral, as the size of the body scarcely admits of two longitu-
dinal sections. Both transverse series and longitudinal sections
show that the sporange was almost always somewhat injured at
the base where it has become detached from the parent plant.
ANATOMY.—The whole sporange is surrounded by a large-
celled epidermis. The contents of the epidermal cells are carbon-
ized, and from the mode of preservation of mucilaginous tissue in
the Pettycur deposits, this blackened condition of the epidermis
evidently precludes the view that it was mucilaginous (fig. 1).
Beneath the epidermis is the hypoderm, composed of about five
layers of cells. This tissue is continuous with the interstitial tissue
between the loculi. In this cortical region are frequently found,

124

BOTANICAL GAZETTE

[OCTOBER

alternating with the peripheral loculi, especially near the apex and
ase, the characteristic vertical sclerotic plates of Heterangium

a
aoa hag view a
apex

Fic. 3.—Diagrammatic drawing from
two slightly oblique longitudinal sections
(CN .386.17, 18), latter of which is nearly
radial at base, and former superficial for upper
third; it illustrates the somewhat spiral direc-
tion of locular series, preservation of spores in
some but not in all loculi, vertical 1. elerangium
of water

pe
presence of ripe spores; central region is injured.

Grievii (figs. 3, 4, 9, 13).
Locur1.—The peripheral
series of loculi which run
longitudinally and somewhat
spirally are more numerous
than the loculi of Telangium
Scottii, numbering in the
middle zone of the sporange
twelve (figs. 3, 9; cf. also
text fig. 4). Their approxi-
mation into groups is some-
times seen near the apex
(CN .383.10). Immersed in
the ground tissue of the cen-
tral region of the sporange,
except at the extreme apex,
there are further loculi, of
which at least four appear
in transverse sections (figs. 3,
12). Text fig. 3 is drawn
from longitudinal sections
too near the periphery to
give the number and disposi-
tion of central loculi. The
origin of additional central
loculi by segmentation of
peripheral loculi is suggested
in some cases (text fig. 4),
and the presence of ripe
spores almost uniformly dis-
tributed in figs. 11 and 12
(CN .307.17, 18) suggests
that the main content of the

young normal sporange was potential sporogenous tissue. Each
loculus is surrounded by a sheath of small, longitudinally ex-

1922] BENSON—HETEROTHECA GRIEVII 125
tended, narrow cells. These sheaths, probably as a result of the
shrinkage of the tissues due to carbonization, often become sepa-
rated from the tissues which must have abutted on them in the
living state. In the case of the central loculi the sheaths are often
ruptured or entirely
dissolved away, leav-
ing the spores among
the elements of the
ground tissue (figs. 5,
11, 12). Small scle-
rotic plates often be-
come incorporated
with the walls of
loculi, and when seen
in profile are very
characteristic (text
figs. 4, 6, stp").

In one synagium
(figs. 11, 12) every
loculus contains nu-
merous ripe spores
of tetrahedral form,

similar in size and
character to those in
the pollen chamber
of Sphaerostoma ovale
(CN.270.1) among
specimens of which
it lies (text fig. 5).
The spores measure
29» in their trans-
verse and 20u in
their radial extent.

Fic. 4.—Diagrammatic drawing of transverse sec-
tion of class II synangium (CN.411.31); swollen ground
tissue not entered in detail; two deeply lying vascular

undles shown in transverse section (vb,, vb.); one pe-
ripheral vascular bundle also cut transversely on left, but
most are cut so obliquely that they are merely indicated
by hatching; nerve ending seen near center with its
delicate branch strand; one or two central loculi are
broken down, and carbonization of peripheral ones prob-
fig. 5); at

in profile as in CN. 307.18, for which consult text fig. 6
and fig. 12.

In this specimen some of the locular walls have broken down, but
many of the peripheral and at least two of the central loculi are
still intact. In other cases spores can be demonstrated only in
some of the loculi, while others show opaque black or dark brown

126 BOTANICAL GAZETTE [OCTOBER

contents, a condition which is possibly the result of the conditions
to which the sporange was exposed during fossilization. As a
rule the spores are better preserved in the interior than near the
surface, which may be due

to the conditions of ex-

posure being slightly

“& 0) — different. In a large
number of cases the con-

G. 5.—Camera drawings of “ayia from s of the loculi have

vice iC oo siael Oh ek kee
middle is characteristic and possibly eae entirely been dissolved,
residuum of spore mother still persisted as in Or are in an abnormal
recent cycads; spores on left drawn from those condition. Such are the

pt gnc aa of Sphaerostoma for comparison series CN .383.10-13 an 3

CN .386.11~-12 (figs. 1-4).
In the series CN .391.23-27, slide 391.26 shows in two cases a
nerve ending in the center of the abortive loculus. In a large
number of cases the peripheral loculi have been carbonized, but not
the central ones.
Swollen nerve end-

TRAL LocuLys
CEN im ,

fiq4 SiR’

angium sclerotic
plates appear to
occupy the whole
of the core of the
sporange in the
most advanced
phyllodic speci-
mens (text fig. 7).
I refer to the par-

talks Ge ent) Fic. 6.—Key to fig. 12, showing outline of sclerotic
‘fi my plates, trig which are ase | in slide than in micrograph.

ATE on WALL.

of Locuuus<¢. Text

abortive specimens

““phyllodic,” as their tissues approximate the tissue elements
of the ordinary sterile petiole of Heterangium. Moreover, they are
linked together as in the petiole. There is a considerable range
of form and size in the plates; some sporangia even seem to have
produced more plates than others (fig. 12).

1922] BENSON—HETEROTHECA GRIEVII 127

The vertical plates in the periphery often have their cells thick-
ened with layers of cell wall substance which almost obliterate
the lumen of the cell; other plates are small, but most show the
hexagonal form of cell indicated in text figs. 3 and 4. Abutting
on these are tubular cells which
are disposed mainly in the
horizontal or transverse plane
(text fig. 3). In the fossil
these are generally swollen, and
owing to their form and pale
color have somewhat the ap-
pearance of macaroni. Some
fibers accompany the delicate
branches of the vascular
bundles, and are continuous
with a parenchymatous hood-
like envelope to the nerve end-
ing. Many, perhaps more in
some specimens than in others,
show a spiral line of thickening
which resists imbibition and
consequent swelling.

The six to eight mesarch
strands of primary xylem which
travel mainly in the peripheral Fic. 7.—Camera sketch of specimen of
region give off the delicate Heterotheca in CN.288.2; no carbonaceous
centroscopically directed xylem matter is retained in center, and therefore
Sivands whidk ond in tie ified elements of ground tissue appear

’ exceptionally clearly; five nerve endings,
aqueous storage tissue. The many transfusion elements, and two vascu-
contrast between the short _ lar bundles can be distinguished in original;
barrel-shape d tracheids of the ee RS of vertical plates (vsp) charac-

i teristic; striated elements seen near apex as
nerve ending and the slender jn many cases (cf. text fig. 3).
carriers of the water is quite
reminiscent of highly organized water storage organs in recent
plants. The majority of the nerve endings in the synangium were
directed to its central region. Transfusion elements of varying
degrees of specialization are exceedingly abundant in some speci-

128 BOTANICAL GAZETTE: [OCTOBER

mens, and in some phyllodic specimens, such as that outlined in
text fig. 7, where the carbonaceous matter is dissolved away in
the center, the wide extent of the striated, possibly lignified, trans-
fusion elements of the nerve endings is very clearly seen by the aid
of the microscope. The nerve endings appear here to have wholly
usurped the position of the central loculi (cf. fig. 6). The enlarged
nerve ending is a familiar feature of the sterile pinna of Lyginopleris,
and probably occurred in that of Heterangium also. The macerated
condition of some of the specimens may be explained by the condi-
tions to which they were subjected during fossilization. If we
accept GorDON’s explanation (8) of the mode of formation of the»
Pettycur plant deposits, we may attribute it partially to the action
of thermal springs and warm pools in which the accumulation of
the plant remains were deposited and gradually infiltrated.

Text figs. 3 and 4, which illustrate the preceding statements,
are both mere diagrams based on definite sections showing ripe
spores. The positions in which the latter are clearly present have
been indicated by S. They were probably present in other loculi,
but were welded together into an impenetrable mass, owing prob-
ably to the presence of some vestige of the spore mother cell, which,
as in recent cycads, appears to have remained long enveloping the
tetrad. In the specimen shown in figs. 11 and 12 the spores are
' free, and there is no welding together of the contents of the loculus.
In text figs. 3 and 4 sclerotic plates are indicated by groups of
hexagonal cells. Two vertical plates can be seen in text fig. 3
(sp), and where plates are incorporated with the wall of a loculus
they are indicated by s‘p'. Larger horizontal plates are also seen
in text fig. 4 in the central region. Vascular bundles, their delicate
ramifications and large nerve endings, are indicated by hatching.
The wall of a loculus has apparently broken down, as shown in
the center of both text figs. 3 and 4, and spores are found among
the swollen fibers. In both diagrams there is strong suggestion
of segmentation of loculi, as Professor Bower kindly pointed out
to me.

Although the distribution of the vascular strands is mainly pe-
ripheral, at least two may be found in the foci of the ellipse formed
by a cross-section (text fig. 4, vb,, vb,), but the number cannot be

1922] BENSON—HETEROTHECA GRIEVII 129

regarded as determined. The peripheral strands probably alter-
nated with every two series of loculi, but owing to the obliquity
of their course (fig. 10 and text-fig. 7) they are often difficult to
distinguish. An interesting point in the structure of the sporange
in detail is the absence of any evidence of the building up of the
synangium by a fusion of sporangia. The whole body strongly
suggests its origin from a single sporange which has shared in the
same type of skeletal elements as the petiole on which it was borne.

The sporogenous regions were distributed fairly equally through-
out the body, except that their disposition in the periphery prob-
ably was determined by the approximately dictyoxylon type of
cortex. If the loculi appear to be of unequal size, this is due
partly to the varying girth of the sporange, and partly to the plane
of section through the loculus. Wherever a section occurs in the
surface plane, as in the upper third of text fig. 3, the buttresses
are seen to lie so obliquely that a transverse section necessarily
cuts through the contained loculi at different angles, and explains
the fact that a transverse section does not differ much in appear-
ance from a longitudinal one, except in form.

GROUPING OF SPECIMENS.—The available specimens, roughly
sixty in number, may be grouped in four classes:

Crass I.—Specimens such as that occurring in CN .307.16-19
(figs. rr and 12), where the vegetative tissue is subordinate in
amount to the sporogenous tissue. Such specimens show septa,
mesarch vascular strands, and only a few water storage elements.
The sclerotic plates characteristic of Heterangium in such sporangia
are well developed, both in the periphery and in connection with
the deeper lying septa.

Crass II.—Specimens such as those occurring in CN.411.30, 31
and CN .386.17, 18 (figs. 5, 10). These contain ripe, apparently
normal spores and normally disposed loculi, but undoubtedly a
larger proportion of vegetative tissue than those in class I (text
figs. 3, 4). The following series also belong to this class: CN.
386.7, 8; CN .395.5, 6, 18, 19; CN .396.4, 5.

Crass III.—Specimens such as those occurring in CN .383.
to-13 and CN .386.11, 12 (figs. 1-4, 8, 9). Although one of these
is possibly an immature form showing carbonization of the spo-

130 BOTANICAL GAZETTE [OCTOBER

rogenous tissue within the loculi, for example, CN .386.11, 12, it is
not possible to be sure of the nature of the carbonized contents.

No recognizable spores occur in any of the specimens included
in class III, and in several series of sections which exhibit the struc-
ture of the body from apex to base, such as that in CN .391. 23-27,
the loculi seem to be filled up by concentric series of blackened
cells, and in some cases have a well defined nerve ending in the
center (CN .391.26).?

The majority of the available specimens belong to class III,
which may be taken to include also specimens such as that in
CN .393.6A (fig. 13), in which vegetative development obtains to
such an extent that the conclusion is obvious that they were abortive
or almost completely so. These specimens are of value as demon-
strating the extreme condition of the phenomenon, and render
probable the suggestion that there was some degree of phyllody
(approximation to pinna structure) even in those of class II. The
sections showing vegetative development are sometimes slightly
larger than those in the normal series CN .307.17-10.

Significance of specimens in classes II and III

The explanation of the state of these sporangia, purely on the
assumption of partial sterilization and maceration before impregna-
tion with calcite, is not wholly satisfactory. In recent plants,
when sporangia abort, the process affects the sporogenous tissue
mainly, as in some specimens of. Angiopteris sporangia, where the
wall and apical crest (annulus) remain unaffected. A mucilage
gland results in several familiar instances (7,16). In the specimens
under consideration, however, the loculi show no sign of a mucilagi-
nous content, but, together with the septa, are represented by @
considerable amount of tissue comparable with that in the vegeta-
tive pinnae of Heterangium, the parent plant.

Kipston and LANG (10) point out that the sporange in Rhynia
and Hornea may be regarded as “corresponding to the tip of a
branch of a thalloid sporophyte, inclosing sunken tetrasporangia.”

* Tracheids possibly formed from degenerating sporogenous tissue of the ovule

have been recorded by Trevs (17) in Casuarina, and by the writer (2) in Castanea,
but it is an unusual phenomenon.

1922] BENSON—HETEROTHECA GRIEVII 131

It is not an organ sui generis, but partakes of the same potentialities
as other branches.

The widely accepted view that the Sphenopterid leaf is a meri-
phyte, and that the pinna corresponds with the cladodified pri-
mary branch axis, makes it easy to conceive of the microsporange
showing in some cases the same anatomical elements as the pinna.
The Sphenopterid type of frond as recorded by ARBER (2) had
already made its appearance in the Devonian, and Heterangium
Grievit may well have retained some reminiscence of the earlier
unspecialized condition from which we conceive the sporange to
be evolved. The curious specimens under discussion, which prob-
ably owe their preservation in_a fossil form to their condition (as
only two or three specimens of class I are so far recorded), are thus
of considerable interest for the pinna-like character they exhibit.
Nor is their more or less sterile condition without significance in
any discussion as to the origin of the seed habit in Heterangium.
Any comparable instability in the homosporous sporangia of the
ancestor could well have been the beginning of a differentiation
into megasporangia and microsporangia. A plant bearing vascular
sporangia which retained but a few tetrads and relatively much
surrounding vegetative tissue might well be regarded as on the
high road to seed formation.

Evidence of synangial origin of seed

It must have occurred to many morphologists that a seed was
a transformed synangium, the nucellus representing the one persist-
ing fertile loculus, and the inner integument the vestigial peripheral
part. In 1904, the evidence then available for this theory of the
synangial origin of the seed was discussed by the writer (4) in con-
nection with the description of Telangium Scottii, a synangium
very common in the Coal Measures of the Upper Carboniferous
rocks of the north of England, and the first species of that genus
to be described showing structure. There were at that time certain
difficulties in the general acceptance of the theory, chiefly because
the structure of Telangium was such that, while explaining the
integument, the absence of any central loculus rendered the explana-
tion of the nucellar or central fertile loculus of the seed difficult.

132 BOTANICAL GAZETTE [OCTOBER

Thus, as the absolute parallel between seed and synangium could
not then be demonstrated, there were critics who preferred to lay
stress on the possibility of the seed having acquired its character-
istic structure independently of its ancestral condition, rather than
by a transformation of structures already present. The inner
integument, as well as the outer or indusial envelope, was attrib-
uted to foliar upgrowths around the nucellus, which alone was
regarded as the representative of the ancestral sporange. The
views of such critics are summed up by OLIVER (13) in his account
of Physostoma elegans in the following words:

oe oe sug d though ne Seale tenable, presupposes in the ancestor
h f a synangium, in which the peripheral :
members were ranged “symmetrically around a central sporangium, and in
which they persist as a sterilized envelope to form the seed coat.

Having at that time already secured several specimens which
indicated the existence of a synangium with central loculi sur-
rounded by peripheral ones, the writer took an early opportunity
of collecting some more of the Pettycur deposits in which these
interesting specimens occurred. By 1911, several hundred sections
had been cut from two of the blocks collected the previous year.
These blocks contained much Heterangium Grievii material, and
yielded the large number of specimens now available of the new
synangium. Owing to the care with which the stones were cut,
many of the synangia, although scarcely 4 mm. in length and 2 mm.
in width, are represented by series of three or four sections in the
transverse plane or two in the longitudinal plane. The average
thickness of the stone involved in the section cutting was 0.8 mm.

As already stated, the series of transverse sections CN .307-
17-19, CN .343.10-13, and CN.412.30-31, although cut from
different blocks, demonstrate clearly with many others that a
synangium was present in these older rocks, associated with and
showing the characteristic cortical structures of Heterangium
Grievit, a synangium in which central loculi, as well as the more
commonly occurring peripheral, occur. It is also interesting that
even in the microsporangial apparatus an unusual amount of
vegetative tissue obtained was also clearly shown for the first
time. The publication of the details of the structure of Sphaero-

1922] BENSON—HETEROTHECA GRIEVII 133

stoma in 1914 was to have been followed by the account of the
microsporange Heterotheca, but other things have claimed atten-
tion, and it has only been since November 1918 that the work has
again been taken up. The investigation of a larger number of
specimens has thrown new light on the structure of Heterotheca,
especially on the character and differentiation of the non-
sporogenous tissue. With the possible exception of Crossotheca
(text fig. 8, II), it differs from all other described microsporangia,
and approaches what must be assumed to be a synthetic type of
seed and microsporange. It is a succulent, sclerotic, vascular
synangium, with central as well as peripheral loculi, and exhibits
in its own tissues most of those found in the seed

If we may have even in sporangia coexistent in the same species
of plant a large amount of vegetative tissue, it is obvious that there
is ground for assuming that in the early phases of evolution of the
seed this would have been available as an envelope to the central
fertile loculus, if the peripheral ceased to form sporogenous tissue.

A difficulty some have had in accepting the theory of the synan-
gial origin of the seed has been expressed by the statement that
“nothing useful has ever been produced by a sterilized sporange.”
It is granted that abortive sporogenous tissue generally eventuates
only in a mucilage cavity, as CoULTER and Lanp (7) and STARR
(16) have shown in particular cases, but useful structures certainly
can be formed by the elaboration of the vegetative tissue surround-
ing masses of sporogenous tissue, as has recently been demonstrated
(6) in the megasporange of Mazocarpon. It is not altogether
sterilized potential sporogenous tissue of the peripheral loculi in
Heterotheca which formed the inner integument of the ovule
(canopy), but mainly an elaboration of the vegetative tissues which
originally surrounded those masses of sporogenous tissue and
finally supplanted them. For example, Azolla and all such lepto-
sporangiate ferns were foredoomed to failure in the construction of a
seed on these lines, as their peripheral sporangia had in all prob-
ability lost their vascular supply and their skeletal tissue before
heterospory was evolved. The parallel to the seed habit which
may be noted in Azolla is limited to the fact that the megasporange
is one-spored, and occupies a central position in the sorus.

134 BOTANICAL GAZETTE [OCTOBER

Fic. 8.—Diagrammatic transverse sections of various Pteridosperm ovules and
pollen sacs to illustrate numerical relations they show to Heterotheca and one
another: on left are a, Sphaerostoma; b, Lagenostoma; c, Conostoma; d, Physostoma;
on right are a', Polylophospermum; ', Trigonocarpus Parkinsoni; o, T. Shorensis;
in center are I, Heterotheca Grievii; II, Crossotheca Hoeninghausi; III, Telangium
Scottii; IV, Codonotheca caduca. Vascular bundles indicated by small ring in each;
arrows denote different phyletic lines; diagrams have been adapted from those of
Scott and MASLEN, OLIVER, OLIvER and SauisBury, SELLARDS, and three of writer’s,
references to which occur in text; relative size of bodies concerned has been neglected
for convenience of comparison.

See

1922] BENSON—HETEROTHECA GRIEVII 135

Lastly, a difficulty in the synangial theory of the seed has often
occurred to the writer, but she has not heard it expressed by others.
It is that in the compartments of the canopy of Lagenostoma a
vascular bundle occupied a central position instead of, as one
might have expected, a position in the plane of the lateral walls.
As will be seen in text fig. 8, this difficulty is completely removed
by the structure of Heterotheca and Sphaerostoma. Each compart-
ment in the canopy of Lagenostoma is equivalent to a pair of loculi,
which, although completely merged in Lagenostoma, can still be
faintly traced in Sphaerostoma.

We owe much to Professor OLIVER for the open expression of
his views published in 1909. The conclusions he finally arrived
at were opposed to those which seem necessarily drawn from our
present knowledge. Both theories as to the origin of the seed
were mere hypotheses in 1908. Unfortunately, the view that the
canopy of Lagenostoma was the product of a cupular or indusial
upgrowth, led to the further hypothesis that the Physostoma seg-
mented integument was a relatively primitive form, and even con-
tributed to a suggestion that Physostoma was perhaps the most

- archaic type of seed known, a suggestion wholly contrary to what

is known of its geological history. In the light of recent work,
these latter hypotheses necessarily fall together, and it is to be
regretted that a recent writer (14) should have referred to them as
facts. OLIVER merely claimed that certain conditions should be
proved to exist ‘in the ancestor,” but evidently the necessary
conditions have persisted in’ Heterangium, so that they coexist
with the formation of an ovule for the megasporangial apparatus.
Thus a link is provided between an ovule and a microsporangium
which is stronger than was demanded, and there can be no longer
any question as to the seed of a Pteridosperm, a seed that may
well have been the homologue of all Pteridosperm seeds, having
been produced in the course of evolution as a transformation
product of a synangium. In this investigation we thus stand
upon the threshold of the origin of at least one group of the Sper-
matophyta, and find more indications of it than were expected
in the structure of a plant of the Lower Carboniferous.

136 BOTANICAL GAZETTE [OCTOBER

The following is a more concise statement of the features of
resemblance between Heterotheca Grievii and various ovules and
microsynangia regarded as homologous with it. For the better
elucidation of the subject, text fig. 8 has been constructed showing
the possible numerical relations, etc., between the various sporangia
of the Pteridosperms. We will commence with a comparison of
Sphaerostoma and Heterotheca.

Heterotheca Grievii resembles Sphaerostoma ovale in the follow-
ing particulars. It is approximately of the same form and dimen-
sions (length 3.5-4 mm., width averaging about 2mm.). It has
probably six peripherally placed bundles in the buttresses between
every two loculi as seen in transverse section. Besides these, there
are two in the foci of the ellipse of the cross-sectional area, making
eight in all, as in Sphaerostoma, although in the latter all eight are
peripheral. The bundles are accompanied by enlarged water
storage elements, and branch as in Sphaerostoma (5), fig. 34.
There is a central fertile region in each. In Heterotheca there is
a large amount of vegetative tissue in the region between the
loculi, forming buttresses vertical to the surface similar to those of
the canopy of Sphaerostoma.

The differences can be explained by progressions of well known
type. Thus the overarching of the central region by the peripheral
at the apex to form the micropyle and sinus may have been partly
in relation to the necessity of harboring the pollen grains, and partly
a direct result of the freer vegetative development of the periphery.
The later segmentation of synangia is a familiar phenomenon in
Pteropsids, as may be seen by a comparison of Angiopteris and
Marattia. The regular circumscissile dehiscence of the pollen
chamber may be reminiscent of the time when there was a whorl
of central loculi such as still exist in Heterotheca.

That there should be so few differences and so many resem-
blances between the microsporange and the ovule of the same species,
makes it impossible to homologize merely the nucellus with the
microsporange; as already stated, we must accept the synangial
origin of the ovule as a whole, and regard the nucellus as derived
from the central part of the common ancestor of both Heterotheca and
Sphaerosioma. ‘That the two structures, borne by the same species,

1922] BENSON—HETEROTHECA GRIEVII 137

should be homologous is undoubtedly the simplest explanation of
their origin. ‘They both separate from the frond, and in this respect
differ from later forms, where, on the attainment of dry dehiscence
in the microsporange, the pollen escaped before the fall of the
sporange. The indusium or cupule which surrounds the ovule as
long as it remains on the parent plant is one of the distinctive
features of microsporange and ovule, for there is no evidence of an
indusium surrounding Heterotheca. ‘This difference, however, is
really confirmatory of the synangial origin of the inner integument,
as such an origin does not involve a double indusial formation in a
relatively primitive ovule. On grounds such as these, it may be
assumed that in the particular case of Heterangium Grievii its
microsporangia and ovules are homologous, both being transforma-
tion products of a common ancestor.

Those who accept this thesis will undoubtedly be prepared to
accept it for all the other Lagenostomales, such as Lagenostoma,
Conostoma, and Physostoma. A necessary corollary as respects
Physostoma is that there has been a meristic variation in the
periphery. The bundles are approximately, or we might say,
potentially twice as numerous as in the periphery of such a spo-
range as Heterotheca, and each dominates one radially symmetrical
“tentacle” instead of a dual compartment as in Spharostoma (text
fig.8,a,d). Thusinstead of regarding Physostoma as a Lagenostoma
with unfused chambers (OLIVER 13), we should, in the light of
Heterotheca, regard it as a Lagenostoma with a lobed canopy.

Turning from the Lagenostomales to the Trigonocarpeae,
which are regarded as the ovules of some at least of the Neurop-
terideae, we may ask if they bear any internal evidence of origin
from such a type of synangium as Heterotheca. They show obvious
series in the structure of the integument, series which in some
respects run parallel to those in the Lagenostomales. Excellent
details of the integument will be found in SALIsBuRY’s (14) work
on Trigonocarpus Shorensis. In the Trigonocarpeae the nucellus is
free from the inner integument except in the plane of its basal
attachment, through which runs a vascular bundle which eventually
forms a tracheal envelope round the nucellus. Six other bundles
enter the integument and travel in its periphery. Polylophosper-

138 BOTANICAL GAZETTE [OCTOBER

mum, Trigonocarpus Parkinsonii, and T. Shorensis show an obvious
series in the reduction of the compartmental character of their
integument (text fig. 8, at, bt, c'). In the two former the six bundles
obviously alternate with compartments as in Sphaerostoma and
Heterotheca, but in T. Shorensis all trace of the buttresses in the
plane of the bundles has disappeared, as in Lagenostoma, and the
bundles appear to occupy a central position.

The numerical relations of the bundles in Heterotheca and the
Trigonocarpeae correspond, if we may assume in the latter a simple
fusion of the two central bundles to supply the megasporange
(nucellus), which in this series of seeds is free from the integument,
and thus necessarily requires a central water supply. The tracheal
mantle which becomes such a prominent organ in some of the
Neuropterid seeds, for example, Stephanospermum (OLIVER 12);
needs no explanation if the nucellus were derived from an ancestral
sporange such as Heterotheca, with its large water storage equip-
ment. Further, the succulent sarcotesta of the Trigonocarpeae is
extraordinarily similar in structure to the succulent ground tissue
of Heterotheca, so far as respects the macaroni-like tubules (text
fig. 3). There is thus a considerable sum of evidence in support
of the homology of the Pteridosperm seeds with a microsynangium
such as Heterotheca.

Let us now turn to a consideration of the other microsporangia
attributed with general assent to Pteridosperms. I shall only refer
to Crossotheca Hoeninghausi (Kipston 9g), Telangium Scotti
(BENSON 4), and Codonotheca caduca (SELLARDS 15), Of these,
Telangium Scotti is the only one in which the details of the anatomy
have been published, but the preservation of the other sporangia
as incrustation fossils is exceptionally good, and it has been possible
to learn much of their organization. Crossotheca Hoeninghaust
shows eight peripheral pairs of loculi, each pair showing a single
vascular bundle running up in its dividing wall. In the young
condition the eight pairs are seen to be in close lateral approxima-
tion, so that they form a body resembling a stout undehisced
Telangium with a wide base. In specimens recently provided by
Mr. HEMINGWAY, there seems no reason to doubt that this younger
condition (occurring nearer the tips of the fronds) represents an

1922] BENSON —HETEROTHECA GRIEVII 139

undehisced condition of a synangium. In Kimston’s original
description (9) the synangium was regarded as built up of eight
discrete dual sporangia. In a transverse section kindly lent by
Dr. KinsTon, it was noted that the matrix within the ring of paired
loculi was stained yellow, and this is suggestive of decayed ground
tissue having been present originally where now only a boss of
rock can be seen.

ZEILLER thought that the members of the whorl were sometimes
coherent. If this be the true interpretation, Crossotheca Hoening-
hausi occupies a position almost halfway between Heterotheca and
Telangium. It resembles Telangium in the possession of a single
peripheral series of loculi, in apical dehiscence, and its retention on
the frond until the spores are shed. It resembles Helerotheca in
the loculi being distributed one on either side of longitudinal discrete
vascular bundles, in the possession of much sterile ground tissue,
and in the number (sixteen) of its longitudinal loculi or loculi
series. It differs from Telangium Scottii in the number of its loculi,
and from Heterotheca in the absence of central loculi and in its
apical dehiscence. I have no evidence as to the character of its
ground tissue, but it is probable that it was non-cuticularized.

From these considerations I have included in text fig. 8, IT an
adaptation of Kmpston’s fig. 9, indicating by hatching the supposed
ground tissue which had perished in the incrustation. It would
seem best to retain the name Crossotheca, as the body is sufficiently
distinct from any species of Telangium to retain its separate form
genus rank.

Codonotheca caduca is regarded by SELLARDS as probably a
Neuropterid sporange. It is fairly safe to regard it as belonging
to some Pteridosperm, and a reference to it may be useful. Like
the Trigonocarpus seeds, it is provided with six peripheral bundles,
but in this case each becomes duplicated. Like the canopy of
Physostoma, the peripheral series have become lobed. There are
no central loculi, which are so far only recorded for Heterotheca.
Telangium Scottii has but half the number of loculi recorded for
Crossotheca, a mutation probably having occurred comparable
with that which gave rise to the reduced number of bundles of
Conostoma, which shows but four (text fig. 8, c). The three series

140 BOTANICAL GAZETTE [OCTOBER

shown in this figure, for example, the Lagenostomales (a—d), the
Trigonocarpeae (a'~c'), and the microsporangia (I, II, III, IV)
illustrate the fact that at least two lines of progression can be
traced in Pteridosperm seeds, each with members suggesting an
early descent from a sporange with paired loculi. These paired
loculi occur in both Heterotheca and Crossotheca. A tendency to
simplification is seen in all three groups, Conostoma among the
Lagenostomales and Telangiwm among the microsporangia showing
a halving of the number of parts. Again an example of lobing
occurs in one seed of the Lagenostomales (Physostoma, text fig. 8,
d), and in one type of microsporangium (Codonotheca, text
fig. 8, IV).
Summary and conclusions

1. Among the remains of Helerangium Grievii (vegetative organs
and seed) in the calcified deposits of plants occurring at Pettycur,
Fifeshire, have been found large numbers of a new type of micro-
sporange for which the form genus Heterotheca has been constructed.

2. Its mechanical structure is similar to that of the petioles of
Heterangium, and, although so far found detached, it is attributed
to Heterangium on the same grounds as are the vegetative organs,
that is, the presence of vertical and horizontal sclerotic plates.

3. Its spore bearing tissue is distributed in sixteen series of
loculi, of which twelve are peripheral and four central. The
vascular bundles are similar to those of the seed, and near the apex
each is nearly surrounded by a pair of loculi as in the canopy of
the seed.

4. The structure throughout is strongly confirmatory of the
homology of the seed and synangium, and is regarded as supplying
ample proof of the synangial origin of the seed.

5. In this investigation we seem to stand upon the threshold of
the origin of at least one group of the Spermatophyta, and the
conclusions reached cannot fail to have their influence on the study
of other groups.

RoyaL Hottoway CoLLecE

ENGLEFIELD GREEN
SuRREY, ENGLAND

1922] BENSON—HETEROTHECA GRIEVII I4I

LITERATURE CITED

coal
.

ARBER, E. A. N., On a new pteridosperm possessing the Sphenopteris
type of foliage. Ann. Botany 22:57-62. pl. 7. 1908.

2. ————. Devonian floras. Cambridge Univ. Press, p. 61. fig. 34.

. BENSON, MARGARET, Contributions to the embryology of the foe
Part I. Trans. Linn. Soc. London 3:412. figs. 7. 1894.

4. , Telangium Scott. Ann. Botany 18:161-177. 1904.
5. ———,, Sphaerostoma ovale. ‘Trans. Roy. Soc. Edinburgh 50:1-15. 1914.
6. , Mazocarpon. Ann. Botany 32: 586. 1918.

7. CouLTER, J. M., and Lanp, W. J. G., Torreya. Bor. Gaz. 39:163. 1905.
8. Gorpon, W. T., On the nature and occurrence of the plant-bearing rocks
at Pettycur, Fifeshire, Scotland. Trans. Geol. Soc. Edinburgh 9: 1909.
9. Kinston, R., the microsporangia of the Pteridospermeae. Trans.
Roy. Soc. London, Series B. 198: 428. 1906.

to. Kipston, R., and Lane, W. H., a = sandstone plants. Part IV.
Trans. Roy. Sac. Edinburgh 52 :Bc2

11. Natuorst, A. G., Paleobotanische “srictdindge. Handl. Kgl. Svensk.
Vetensk.-Akad. 43:1-12. figs. 3. 1908.

12. OLIVER, F. W., Structure and afinities of Slephanospermum. Trans. Linn.
Soc. London 6: 361-400. 1904.

, On Physostoma duels Williamson, an archaic type of seed from
the Palsceile rocks. Ann. Botany 23:103. 1909.

14. SALISBURY, E., Trigonocarpus Shorensis. Ann. Botany 28:74. 1914.

15. SELLARDS, E. H., Notes on the spore-bearing organ Codonotheca, and
its relationship with the Cycadofilices. New Phytol. 6:175-178. 1907.

16. Starr, A. M., The microsporophylls of Ginkgo. Bor. Gaz. 49:53. I910.

17. TREUB, M., Sur les Casuarinées. Ann. Jard. Bot. Buitenzorg 10:172.
1891.

EXPLANATION OF PLATES IV AND V

The following abbreviations are used in the illustrations: 6, buttress or
interstitial tissue between peripheral loculi; ¢, epidermis; g, gap in stone
section; gt, ground tissue; /, loculus; cl, central loculus, me, nerve ending;

res; sp, sclerotic plate; i plate attached to loculus wall; vsp, vertical
sees plate; vb, vascular bun
PLATE IV

Fics. 1, 2.—TIwo successive cross-sections of immature synangium;
epidermis is preserved, and in center of body occur small sclerotic plates;
no central loculi can be distinguished, and content of peripherous ones is
amorphous; matrix has been left around fig. 1 (CN .386.11,12); X33 diameters.

Fics. 3, 4.—TIwo successive cross-sections of synangium nearer base;
central loculi well shown (CN.383.12, 13); X29 diameters.

142 BOTANICAL GAZETTE [OCTOBER

Fic. 5.—Transverse section of mature specimen, showing many of loculi
with ripe spores, some of which, owing probably to solution of loculus wall,
lie free’in ground tissue; rough diagram of this section given in text fig. 4
(CN .411.31); X37 deities:

Fic. 6.—High power photograph of ea ground tissue of obliquely
longitudinal section, showing highly organized nerve ending (ve), various
horizontal sclerotic plates, and succulent ground tissue like that of sarcotesta
of Trigonocarpeae; in original, striated elements of transfusion tissue can be
seen above nerve ending (CN .304.2); zoo diameters.

Fic. 7.—Transverse section through upper part of synangium, showing
central loculi and position of nerve ending (CN.411.12); 18 diameters.

PLATE V

Fics. 8, 9.—Two sections across another synangium, showing position of
loculi in spite of some degree of maceration and subsequent shrinkage; in
fig. 8 plane is nearer apex; surface is seen abutting on other tissues in matrix;
in none of the four sections of this series are spores to be detected; fig. 8 .
(CN 2391.23), X25 diameters; fig. 9 (CN.391.24), X40 diameters.

Fic. 1o.—Nearly peripheral tangential section, showing in original the
transversely oriented series of loculi, of which majority show tetrads of spores;
cf. text fig. 3, constructed from two successive longitudinal sections; it is given
to show transversely running strand (vb), for which reason the rest is slightly
over exposed (CN .386.17); 42 diameters.

Fics. 11, 12.—T wo successive transverse sections of class I synangium,
in which spores are free from one another and all loculi are full of them; syn-
angium had undergone some degree of maceration, as shown by sclerotic plates
(sp), cells of which show partial solution of middle lamella; key provided for
fig. 12 in text fig. 6, to indicate position of sclerotic plates, loculi, etc., which
are clearer in the fossil, although many of the walls have given way; fig. 11
(CN .307.17), X27 diameters; fig. 12 (CN.307.18), X50 diameters.

Fic. 13.—Transverse section clearly showing vertical sclerotic plates
(usp); most of loculi have perished, but one is indicated (J); several others are
easily detected in the slide (CN.393.6A); X32 diameters.

BOTANICAL GAZETTE, LXXIV PLATE IV

BENSON on HETEROTHECA

BOTANICAL GAZETTE, LXXIV PLATE V

BENSON on HETEROTHECA

EARLY EMBRYOGENY OF REBOULIA
HEMISPHAERICA

(WITH FORTY-SEVEN FIGURES)
A. W. DUPLER

Our knowledge of the development of the sporophyte of Reboulia
dates back to HoFMEISTER (11), who described its early stages and
its rapid growth as it approaches maturity. KreniTz-GERLOFF
(13), who studied the embryogeny of a number of forms, claimed the
Reboulia embryo to be similar to that of Grimaldia, certain stages
of which he described in some detail, but not including the earliest
stages. LritcGEB’s (14) work on the Marchantiaceae included a
study of Reboulia, of which he described the development of the
sporophyte in a general way. CAVERS’ (3) observations also in-
cluded the early and late sporophyte of Reboulia. ‘The more recent
work on the embryo has been done by WoopBurRN (18) and Haupt
(10), the former dealing with the very early stages, the latter de-
scribing the development from beginning to maturity. These two
recent accounts differ somewhat from the earlier studies, and in
certain features from one another. A study of the writer’s collec-
tions of material has yielded certain results which may be of interest
in comparison with these accounts, especially where they bear on
their differences, and in the addition of certain facts not mentioned
by them. Altogether it is clear that the embryo of Reboulia shows
considerable variation in the early phases of its development.

Material

The material for this study was collected near Huntingdon,
Pennsylvania, the greater bulk of the embryos figured having been
secured from collections made from the early part of October to
the latter part of November, 1919. None of the material collected
in September shows embryos so far as it has been examined. The
early winter condition (figs. 46, 47) was secured from a collection
made December 23, 1920. The material was killed in 25 per cent
chrome-acetic acid, and for the most part stained by the iron-alum
143] [Botanical Gazette, vol. 74

144

BOTANICAL GAZETTE

[OCTOBER

haemotoxylin method. As Duranp (7) found in Marchantia, the
embryo stains much lighter than the surrounding calyptra, and it
was found that dipping the slides for a short time in an alcoholic

nia to receptacle
axis of thallus (solid line); dotted line indi-

and longitudinal
cates median through bilateral arche-
gonium and embryo; fig. 3, median longi-
tudinal section of mature archegonium; dark
area about embryo represents space between
embryo and calyptra; fig. 3, X400.

solution of Lichtgriin served
to bring out clearly the deli-
cate cell walls. This clouds
the cytoplasm of the cells to
a slight extent, and is not to
be recommended when the
details of cell structure are to
be studied.

Archegonium

The writer has found
nothing in the development
of the archegonium differing
from the account given by
Haupt (9). It first appears
when the female receptacle is
yet quite small, and when the
sex organ is mature the recep-
tacle is still a low conical
structure (fig. 1), surrounded
by a large number of sterile
scales (fig. 2). The venter of
the archegonium is inclined
somewhat below the horizon-
tal, the neck curving upward
more or less to a perpen-
dicular position among the
scales. Haupt (9) regards
these scales as probably pro-
tective in function. They
also probably serve in holding

a film of water about the archegonia, functioning much as do the |
paraphyses about the sex organs of mosses, resulting in conditions
which increase the probabilities of fertilization.

1922] DUPLER—REBOULIA 145

Usually there are four archegonia on each receptacle, one close
behind the apical cell of each of the four growing points of the recep-
tacle. Rarely three, occasionally five or six such growing points
and archegonia may occur. In the typical condition the archegonia
are so situated on the receptacle that a median section through the
entire archegonium can be secured only by vertical sections cut on a
plane at an angle of 45° to the long axis of the thallus (fig. 2). Owing
to their curvature, both the archegonium and the early embryo are
bilateral and not radial, and a strictly median section can pass
through but one plane. With but few exceptions all the embryos
figured in this account are from sections along this plane.

The egg at maturity is about twice as long as its transverse diam-
eter, bluntly rounded at both ends, slightly more tapering at the
hypobasal end, and with its long axis describing the arc of a circle
- (fig. 3). The nucleus is centrally placed, the egg cytoplasm uni-
formly distributed, and containing plastids and oil globules. There
is usually a very conspicuous oil globule near the anterior end, which
persists even in late stages of the embryo.

Fertilization

The close proximity of the male and female receptacles on the
same branch of the thallus usually insures fertilization, although
occasionally it fails to occur. Woopsurn calls attention to the
change which the motile sperm undergoes from the time it leaves
the antheridium until its nucleus is ready to fuse with the egg
nucleus. The writer found a number of cases in which the sperm
nucleus had penetrated the egg cytoplasm and lay close to the egg
nucleus (fig. 4). At this time the egg nucleus has about twice the
diameter of the sperm nucleus, whose more compacted chromatin
results in a denser staining body. No attempt was made to study
the nuclear changes involved in fertilization. Apparently the fusion
nucleus passes into the resting stage before division of the egg takes
place.

Embryo

First DIVIsIon.—Without any considerable enlargement after
fertilization, the egg divides by a transverse wall, usually per-
pendicular to the long axis, and giving nearly equal epibasal and

146 BOTANICAL GAZETTE [octoBER

hypobasal cells (fig. 5). This agrees with the accounts for Reboulia
as given by CAVERS (3), WoopBuRN (18), and Haupt (10), and with

wr 4
Ve

(ICED

FEDLHY KS

PRI CTT

Fics. 4-18.—Fig. 4, egg with male and female nuclei, black circle representing
oil drop; fig. 5, first wall transverse; fig. 6, first wall oblique; fig. 7, mitosis in hypo-
basal cell; fig. 8, embryo of three cells; fig. 9, mitosis in both epibasal and hypobasal
cells; fig. 10, typical filamentous embryo of four cells; figs. 11~13, epibasal cell divided
by oblique wall; fig. 14, vertical division of two middle cells of row, basal and apical
cells undivided as yet; fig. 15, apical cell not yet divided by vertical wall; fig. 16,
epibasal cell divided by oblique wall, vertical division in middle of embryo, basal cell
of row of four probably transversely divided; figs. 17, 18, two cells.at base probably
resulting from transverse division of basal cell; 430.

such forms as Targionia (CAMPBELL 1, O’KEEFE 16), Plagiochasma
(STraRrR 17), Conocephalum (CAVERS 2), Riccia at times (GARBER 8),
and practically all the Jungermanniales which have been examined,

1922} DUPLER—REBOULIA 147

among which are Sphaerocarpus and Geothallus (CAMPBELL 1),
Aneura (LEITGEB 14, CLAPP 5), Fossombronia (HUMPHREY 12),
Pellia (Kren1tz-GERLOFF 13), and Symphyogyna (McCorMIcK 15),
and is in contrast with forms in which the first wall is more or less
oblique, as occurs in Riccia (Kienitz-GERLOFF 13, CAMPBELL 1,
GARBER 8), Marchantia (DURAND 7), and Preissia (KieNITzZ-
GERLOFF 13).

HOFMEISTER thought the Reboulia egg divided first by a strongly
inclined wall. Lrrrces claimed the first wall to be generally
oblique, occasionally perpendicular, to the long axis. Haupt (10)
states that the first division is ‘always accompanied by a transverse
wall.”’ WoopBuRN’s statement is not so positive, and one of his
figures shows the first wall slightly inclined. The writer found
several cases in which the first wall was more or less oblique, some-
times with the epibasal cell the larger of the two (fig. 6).

FILAMENTOUS EMBRYO.—The published accounts differ consider-
ably as to the behavior following the first division. HoFMEISTER de-
scribed the growth as due to an apical cell with two cutting faces, the
epibasal cell dividing repeatedly by alternately inclined walls, result-
ing in a slender embryo of two rows of cells. K1ENITZ-GERLOFF
not convinced by HoFMEISTER’S account, but concluded from oe
ogy with Grimaldia that in Reboulia an octant is formed by vertical
walls perpendicular to the first transverse wall. Lrrrcrs claimed
quadrant formation by walls perpendicular to the first, the apical
and basal cells of the quadrant being the larger, since the first wall
is usually oblique, and both the epibasal and hypobasal cells are
divided unequally. Cavers (3) also claimed an octant by the for-
mation of perpendicular walls, and regarded the epibasal half of the
octant as giving rise to the capsule, the hypobasal to the foot and
stalk. The studies by WoopBuRN, Haupt, and the writer do not
agree with these earlier statements. In most cases the second and
third divisions are parallel to the first, resulting in a filament of four
cells, with the walls between them more or less parallel to one
another.

Woopsurn and Haupt both claim the second division to be in
the epibasal cell, resulting in a row of three cells. 'WooDBURN says
the third division may be in either the apical or the middle of these _

148 BOTANICAL GAZETTE [OCTOBER

three cells; Haupt states that it is in the apical cell. According to
both workers the first division of the hypobasal cell does not take
place until after the formation of the row of four cells, and then
usually by a vertical wall. Haupt says that occasionally this verti-
cal wall formation takes place before the third transverse division,
that is, when the embryo consists of but three cells. Neither Woop-
BURN nor Haupt show mitotic figures definitely proving this sequence
of division. The sequence of these early divisions may hold a definite
relation to the later differentiation of the sporophyte into foot, stalk,
and capsule regions. The writer’s preparations show that transverse
division may take place in both hypobasal and epibasal cells (fig. 9),
and that the division of the hypobasal cell precedes that of the epiba-
sal cell (fig. 7). The division of the hypobasal cell may be completed
before the épibasal cell begins to divide, resulting in a three-celled
filament (fig. 8). Such embryos are probably quite rare, however,
the writer having found but a single case. It is more probable that
the division of the epibasal cell is generally initiated before that of
the hypobasal cell is complete (fig. 9), and the four-celled embryo
results with the completion of the two division processes (fig. 10).
The writer concludes, therefore, that at this stage the embryo con-
sists typically of a row of four cells with parallel walls, as a result of
the transverse division of both hypobasal and epibasal cells, the
division of the former preceding slightly that of the latter. Not a
single case was found suggestive of the quadrant, as claimed by
Cavers, who probably based his interpretation on later stages with-
out having observed these early ones, as he shows no figures of early
embryo development.

Variations from the typical situation are of interest. For
example, the transverse walls are often more or less curved, with the
concave side toward the apex, the curvature often being especially
pronounced in case of the apical cell (figs. 10, 17); or the division
of the epibasal cell may be by an oblique wall (figs. 11-13) whose
inclination to the perpendicular may show considerable variation.
Such a division of the epibasal cell is more likely to occur when the
first division has been an oblique one (figs. 11, 12), although the
inclination of this wall may be independent of the first wall (figs-
13, 16). Woopsurn figures several embryos showing oblique walls

1922] DUPLER—REBOULIA 149

in the epibasal portion. Haupt thinks oblique walls do not occur
at this stage or later. It seems to the writer that the evidence for
the occasional occurrence of oblique walls is conclusive.

The occurrence of a filamentous embryo in Reboulia agrees
with the embryo described for Plagiochasma (STARR 17), Targionia
(O’KEEFE 16), Geothallus, and Sphaerocarpus (CAMPBELL), as well
as practically all the Jungermanniales. Quadrant formation by
walls vertical to the first wall occurs in Riccia (CAMPBELL 1), in
Marchantia, as given by a number of writers, DuRAND’s account
being the most complete, Conocephalum (CAVERS 2), and Fimbriaria
californica (CAMPBELL). KiENiTz-GERLOFF made a similar claim |
for Grimaldia and Preissia, but did not have the early stages.
GARBER found occasionally a row of three cells in Riccia natans,
although the quadrant form was the rule. In the following ac-
count the innermost cell of the filament of four cells will be desig-
nated as the basal cell, the outermost as the apical cell.

VERTICAL WALL FORMATION.—Vertical walls now begin to form
in the young embryo. According to Haupt, “these vertical divi-
sions begin at the lower end of the embryo, a feature which is also
noted by WoopBuRN’s figures.’’ This probably is‘the general rule,
and is evidenced by Haupt’s figures, which show mitoses in the hypo-
basal portion before occurring in the epibasal portion, the basal cell
evidently dividing first. It is quite common to find embryos of this
stage with the apical cell yet undivided (figs. 14, 15). This cell
also soon divides, either by a vertical wall or otherwise, as described
later. A series of cross-sections of an embryo at this stage shows
that the vertical walls do not usually lie in the same plane, but are
inclined to one another at various angles (figs. 19-23). These verti-
cal walls are usually perpendicular to the transverse ones, which, if
obliquely inclined, usually result in oblique vertical walls, and the
embryo may, in surface view of this and later stages, appear spiral.
Occasionally some of the vertical walls are oblique to the transverse
wall, even in the middle of the filament (figs. 17, 28).

The first vertical walls are soon followed by a second series, usually
at right angles to the first, typically dividing each segment into four
cells (figs. 25, 26). These divisions may be more or less simultaneous
(fig. 36), although not ordinarily so even in the same segment.

150 BOTANICAL GAZETTE [OCTOBER

Should the apical cell also divide by the two series of vertical walls,
the apex of the embryo will consist of four octohedral cells (fig. 33).
This is the situation as described by Haupt. Lerirces describes a
similar condition in Blasia. Owing to the curvature of the embryo
two of these will be nearer the neck of the archegonium than the
other two.

APICAL CELL.—The apical cell of the row of four may divide ver-
tically, or, as certain embryos suggest, it may divide again trans-
versely (fig. 29) before vertical division takes place, although in

SQOVO
@ GOS

I9Q-27 —Figs «19-23, eeripc at PEACO rh +1 1
tion of quad walls ‘s one another in successive segments: sen ee is basal cae
fig. 23, apex; fig. 24, transverse section of apical segment of embryo, x is neck of
archegonium; figs. 25-27, transverse section of embryo with segments in quadrants;
compare fig. 27 with fig. 42, noting position of walls; 570.

the absence of a mitosis one cannot be absolutely positive on this
point. It may also divide by an oblique wall, whether its basal wall
is oblique or transverse (figs. 31, 32, 34, 35). WOODBURN shows a
similar situation, to which Haupt takes exception, claiming that in
his investigation ‘‘a truly median section has never revealed the
presence of a triangular apical cell.” Lerrces found that in
Blasia the apical cell may divide by oblique walls, and he figures
several embryos with a triangular apical cell. The writer’s observa-
tions of Reboulia confirm WoopBuRN’s statement. In fact, owing
to the curvature of the embryo, a truly median section is the one

1922] DUPLER—REBOULIA 151

most likely to show the oblique inclination of the wall and the con-
sequent triangular apical cell, although one would not necessarily
err even in the interpretation of an oblique section. It seems to
the writer that there is no room for doubt as to the. presence and
functioning of a triangular apical cell (figs. 34-39, 41, 45). It
is not probable that this cell functions as an apical cell more
than a very few times, being soon “lost” in the growing embryo,
where the apical function becomes distributed to a number of cells
(figs. 40, 46).

BASAL CELL.—The basal cell of the row of four also does not per-
form uniformly in all cases. It may divide by a vertical wall into
two approximately equal cells (fig. 36), or it may divide by an oblique
wall (fig. 35). Wooppurn found “basal cells of triangular shape”
to occur, probably arising as a result of oblique wall formation in the
basal cell. Haupt found no case of this, and in the writer’s prep-
arations it is not common. Should the first wall of the divided egg
be an oblique one, it might be probable that the hypobasal would
divide obliquely, resulting in a triangular cell at the base. While
no mitosis was found as a direct proof, the appearance of a number
of embryos (figs. 16-18, 30-32, 34) suggests that the basal cell may
divide transversely instead of vertically, the basal of the two cells
thus formed behaving as here described for the basal cell itself,
while the other cell sooner or later becomes divided by vertical walls
in the same way as its neighboring segment (figs. 28, 29). Vertical
wall formation in this cell would probably be delayed for a time and
the cell remain undivided, even after vertical walls have formed in
the segments anterior to it (figs. 34, 36). It seems to the writer that
very frequently the basal cell of the row of four undergoes no further
division whatever, but very early becomes differentiated as a large
conspicuous foot cell at the base of the embryo, retaining its hemi-
spherical shape, very early showing denser contents than the other
cells of the embryo, and becoming coated on its free margin by a
heavy thickening (figs. 45-47). This cell often remains quite dis-
tinct, even in late embryos, and may clearly be recognized both in
sections (fig. 47) and in surface views of dissected embryos. Should
the basal cell have divided transversely (as already suggested) the
basal of the two cells formed may remain undivided. WoopBuRN

152 BOTANICAL GAZETTE [OCTOBER

Fics. 28-41.—Fig. 28, embryo with segment divided by oblique wall; fig. 29,
apical cell (of row of four), probably divided transversely; figs. 30-41, embryos show-
ing varying features, figs. 36, 37, and 41 cut at plane perpendicular to median longi-
tudinal plane; in fig. 36 division is going on at several different regions of embryo;
dotted li t ts obli il ing d

2 t q parating deeper cell (in process of division)
from superficial cell with oil drop and undivided nucleus; figs. 34, 35, 37-39 show
functional triangular apical cell; 430.

1922] DUPLER—REBOULIA 153

cites a case where the basal cell has divided into a small group of
irregular cells, probably also a very rare feature.

It is evident that the basal cell of the filamentous embryo under-
goes but few, and in some cases no further divisions, and therefore
makes a relatively small contribution to the tissue of the sporophyte,
which therefore is built up almost entirely from the three anterior
cells of the filament of four cells.

LATER GROWTH AND EMBRYO DIFFERENTIATION.—Along with or
following the formation of vertical walls, transverse divisions in
some or all of the segments result in additional tiers of cells, the divi-
sions occurring in different planes without any definite sequence
(figs. 36-41). At first the ventral side of the embryo will probably
show the greater number of cells (figs. 35, 39, 40), but as growth
continues the dorsal side also grows rapidly, and the embryo soon
becomes a radial instead of a bilateral structure (fig. 46). Periclinal
walls now form, especially in the epibasal portion of the embryo,
without any definite sequence, forming inner and outer cells (figs.
38-44). These first periclinal walls are most likely to form in the
capsule-forming region of the embryo, which becomes considerably
broader than the more slender hypobasal portion (figs. 40-45).
This portion, however, soon broadens out somewhat and reaches the
winter condition (fig. 46). While it is impossible to trace back ab-
solutely the origin of the different regions of the sporophyte, it
seems most probable from the writer’s study that the first division
of the egg determines the capsule region as distinguished from the
foot and stalk region, the epibasal cell giving rise to the capsule,
therefore, the hypobasal to the stalk and foot, with the bulk of both
foot and stalk derived from the anterior half or three-fourths of the
original hypobasal cell. They are derived from the anterior half if:
the basal cell (of the row of four) does not undergo transverse divi-
sion, and from the anterior three-fourths if the basal cell should
divide transversely. Both Woopspurn and Haupt regard the foot
as derived from the hypobasal cell, the stalk and capsule from the
epibasal cell; the capsule being formed from the two anterior cells
of the three derived from the epibasal cell, according to Haupt.
The sequence of the early divisions and the behavior of the hypo-

154 BOTANICAL GAZETTE [OCTOBER

basal portion of the embryo would seem to warrant the writer’s
interpretation.

While it may be probable that the future sporogenous tissue is
cut off from the capsule wall by the first periclinal walls which form
in this portion of the embryo, it does not show differential staining
until later, when the physiological differentiation becomes evident,

as shown in the more massive

EIS Glo\ capsule (fig. 46) of the winter
GE olojop condition. Cavers (4) holds
to the view that “‘the capsule

. wall in Marchantiales is not
>. differentiated until a rela-
o\ tively late stage; that is, the
separation of the archespo-

rium is not determined by the
first periclinal divisions in the
young capsule.” Further de-
velopment takes place the
succeeding spring, with the
sporophyte reaching ma-
turity, in this latitude from
the middle of May to the
middle of June. The writer
: has not made a careful study

Fics. 42-47.—Figs. 42-44, transverse : ?
sections of embryos showing first periclinal of sporogenesis, Haupr's
walls; fig. 45, longitudinal section of young Paper giving an account of

embryo late in November (note prominent the features in detail.
basal cell); fig. 46, embryo in winter con-

dition; 350; fig. 47, base of embryo in Calyptra and involucre
winter condition (large basal cell quite con-
spicuous). The calyptra grows apace

as the embryo develops, be-
coming several layered and relatively somewhat massive. The
longitudinal axis of both embryo and calyptra becomes more and
more vertical, until finally it is practically perpendicular to the
substratum, with the neck of the archegonium hanging downward.
The calyptra incloses the sporophyte until spring, when the rapid
growth of the latter breaks through the slower growing calyptra

1922] DUPLER—REBOULIA 155

and becomes exposed, excepting where covered by the receptacle
tissue, which has grown downward and formed an involucre about
both calyptra and sporophyte, dorsally and laterally.

Discussion

The finding of filamentous embryos in an increasing number of
Marchantiales makes it evident that the octant type of embryo is
not necessarily the rule in this group, in contrast with the filamen-
tous embryo of the Jungermanniales. This, together with the occur-
rence of oblique walls and even a triangular apical cell, tends to
bring the Marchantiales and Jungermanniales closer together as
regards their embryogeny, and in an occasional partial agreement
with that characteristic of the Musci.

In a previous paper, the writer (6) referred to the plasticity of
Reboulia as shown by the male reproductive structures. ‘The varia-
tions found in the development of the embryo give additional sup-
port to that view.

In the differentiation of the capsule region from the foot and
stalk, Reboulia is probably like that of most Marchantiales, in that
the capsule is generally derived from the epibasal half of the egg.
Even in Reboulia there is no absolute proof that the epibasal cell
may not contribute in part to the stalk region, as is the case in the
Jungermanniales. The behavior of the basal cell of the filament is
suggestive of an approach to the situation in some of the Junger-
manniales where the entire hypobasal cell is a mere appendage to
the embryo.

Summary

. The mature egg and early embryo are elongated, slightly
caved bilaterally symmetrical bodies.

2. Fertilization takes place in October, the development of the
embryo beginning at once, the sporogenous tissue becoming dif-
ferentiated by winter, the sporophyte maturing in May and June.

3. The early embryo shows considerable variation in its develop-
ment, the chief features being: (1) the first division of the egg may
be transverse or oblique; (2) transverse division of both hypobasal
and epibasal cells results in a filamentous embryo of four cells;

156 BOTANICAL GAZETTE [OCTOBER

(3) vertical wall formation occurs in these four cells, with the ex-
ception, commonly, of the basal cell; (4) oblique walls may occur
in any part of the embryo, and are not uncommonly to be found in
the apical region where they may form a triangular apical cell,
functional in the cutting off of a few segments; (5) the foot and
stalk are probably derived from the hypobasal cell, the epibasal
cell giving rise to the capsule, although it may conceivably make
some contribution to the stalk as well; (6) the basal cell of the
row of four varies in its contribution to the tissue of the foot, at
times apparently remaining undivided, in which case the remainder
of the foot and the stalk is derived from its sister cell.

4. The variations in the early embryo support. the view that
Reboulia is a plastic form, and as such may occupy a genetic position
among the Hepaticae.

JuntATA COLLEGE
Hontincpon, Pa.

LITERATURE CITED

1. CAMPBELL, D. H., Mosses and ferns, 3d ed. New York.
2. CAVERS, F., On die structure and iesag of Fegatella conica. gre Botany
18:87-120. oe. 6,7. figs. 28-31. 190.
3. ———, Notes on Yorkshire She III. Reboulia hemisphaerica (L.)
Raddi. Naturalist 1904:242-250. pil. 8. figs. 2-6
e interrelationships of the Serie, New Phytol. Reprint
no. 4. \Conbidilan: IQIl.
Crapp, GRACE L., The life history of Aneura pinguis. Bor. GAZ. 54:177-
193. pls. Q-12. 1912.
. Dupter, A. W., The antheridium and male receptacle of Reboulia hemi-
sphaerica. Amer. Jour. Bot. 9:285-295. pl. 14. figs. 24. 1922.
. Duranp, E. J., The development of the sex organs and sporogonium of
Marchantia polymorpha. Bull. Torr. Bot. Club 35:321-335. pls. 21-25:

1908. :

8. GARBER, JOHN F., The life pind of Ricciocarpus natans. Bot. GAZ.
37:161-177. pls. 0, 10. figs. 4.

9. Haupt, A. W., The eons i se sex organs of Reboulia hemis phaerica.
Bot. Gaz. 71: me —74. figs. 21. 1921.

, Embryogeny and sporogenesis in Reboulia hemisphaerica. BOT.
GAZ. 71:446-453. pl. 33. figs. II. 1921.

11. Hormeister, W., On the germination, development, and fructification of
the higher Cryptogamia. Eng. trans. by F. Curry. London. 1862.

1922] DUPLER—REBOULIA 157

to.

4
Ea

UMPHREY, H. B., The get of Fossombronia longiseta. Ann.
Botany 20:83-108. oon 5-7.
IENITZ—GERLOFF, F., Fiesta Re ee iiber die Entwick-
lungsgeschichte des Pebdnaocnoiscatenis. Bot. Zeit. 32:161-172; 33:

1875.
LeITcEB, H., Untersuchungen iiber die Lebermoose. I. Blasia pusilla.
1874; III. Die frondosen Jungermannieen, 1877; VI. Die Marchanti-
aceen. 1881.

- McCormick, FLORENCE a A study of aciosgents aspera. Bot. Gaz,

58:401-418. pls. 30-32.
O’Keere, L., Structure ae develonmnent of Targionia hypophylla. New
ipheag 14: 105-116 jigs. 2. 1915.

, A Mexican Aytonia. Bor. Gaz. 61:48-58. pls. 1-4. figs.
33: gre
Woopsurn, W. L., Preliminary notes on the embryology of Reboulia
hemisphaerica. Bull. Torr. Bot. Club. 46: 461-464. pl. 19. 1920.

SPECIFIC ACIDITY OF WATER EXTRACT AND OXALATE
CONTENT OF FOLIAGE OF AFRICAN SORREL’
GEORGE PELHAM WALTON
(WITH ONE FIGURE)
Foreword

This report is submitted, not so much as a contribution to the
accumulated data on the composition of the leaves of Rumex
abyssinicus Jacq., as for the purpose of directing the attention of
food and drug analysts to a comparatively simple procedure by
which much of value may be learned about the source of the acidity
in certain acid materials, with the minimum expenditure of time
and effort. The scheme outlined in this paper has already been
applied by the writer to a study of dried apple pomace and pectin
pulp, with gratifying results, and it is believed that it should prove
of value in the study of other feeding stuffs of an acid character.

Material examined
Among the plants brought to the United States for further study
by the Office of Foreign Seed and Plant Introduction of the United
States Department of Agriculture in 1919 was a native African sorrel,
Rumex abyssinicus Jacquin.? The stock was brought from Angola,
Portuguese West Africa, where the foliage is reported to be used as
greens for human food. Dr. DAvip Farrcutp states as follows:

Preliminary trials at various points in this country have shown this species
to possess distinct promise as a summer vegetable. By sufficient parboiling

it is distinctly agreeable, and since it is devoid of all stringiness it deserves to
be widely known in America. The plant grows to a height of eight feet and
produces an amazing amount of greens throughout the summer. _ It is as resist-
ant to heat as New Zealand spinach and Swiss chard.

Dr. ARNO VIEHOEVER suggests caution, however, in the use of
this material for food. The following statement by him: was written
after the completion of the chemical work reported in this paper.

* From the Cattle Food and Grain Investigation enemies Bureau of Chem
istry, United States Department of Agriculture, Washington

2S.P.1. no. 48023. 3 Amer. Food sou January 1922.

Botanical Gazette, vol. 74] . [158

1922] WALTON—AFRICAN SORREL 159

The presence of considerable amounts of oxalic acid, as found in the Bureau
of Chemistry, in the form of soluble oxalates, as well as calcium oxalate, suggests
caution. It is a well known fact that some people are especially susceptible to

’ . c . an d i : . 4 ee Pe 4% : Se a

salic ari

leaves are by no means rare. It appears possible, however, that by the addition
of calcium carbonate the soluble oxalates may be precipitated, and thus t
major portion of the objectionable ingredient may be eliminated. Another
means suggested, and possibly equally effective to make the product available
for general consumption, would be the removal of the water in which the material
has been soaked and boiled. At any rate, we have here a product which may
be placed on the market, and which may be used as a substitute for spinach and
other greens, but the identity and characteristics of which should be known to
the consuming public and especially the food officials concerned with the wel-
fare of the people

Several plants started in the vicinity of Washington in 1920
made vigorous, healthy growth (fig. 1). Because of the promising
character of the plant as a source of summer greens, it was decided
to submit a sample to the Bureau of Chemistry for a determination
of its oxalic acid content. The suggestion was made, however, that
in order to decide the question of its wholesomeness it was essential
that both the total (titrable) acidity and specific acidity (H-ion
concentration) of a water extract of the material be determined, as
well as the total oxalate content. These determinations were
undertaken in conjunction with the colorimetric determination of
specific acidity in certain feeding stuffs.

TABLE I
DIMENSIONS OF LEAVES OF SAMPLES IN MM.

SAMPLE NO. 38330 SAMPLE NO. 38340
DIMENSION
Largest | Smallest —_ Largest. | Smallest —
- Length of blade.......... 195 75 149.0 260 230 249
Extreme breath ofblade..| 150 45 118.0 250 200 220
ips of date MONE eas 120 40 86.5 140 100 125

On August 5, the plants in Washington being at a suitable stage
of growth, a sample of about one pound of fresh foliage was analyzed.
Practically all of the material obtained consisted of sound, crisp
leaves with petioles. As there were two distinct sizes of leaves,
the material was divided into two samples. The dimensions of the
leaves constituting these samples are given in table I.

160 BOTANICAL GAZETTE [OCTOBER

Fic. 1.—Row of plants of Abyssinian Rumex, about 6 feet high, grown at Yar-
row Plant Introduction Garden near Rockville, Md. Photograph furnished by Office
of Foreign Seed and Plant Introduction, Bureau of Plant Industry, U.S. Department
of Agriculture.

1922] WALTON—AFRICAN SORREL 161

Procedure
MOISTURE

The bulk of the material of each sample was used for the deter-
mination of moisture, but only entire leaves, with their petioles,
were taken. After recording the total green weights, the midribs,
larger veins, and petioles were split by a sharp knife to facilitate
evaporation, and the material was rapidly dried at 65°—70° C. ina
well ventilated oven, until friable. It was then crushed, care being
taken to avoid loss of substance, and the samples finally dried to
constant weight at 65°-70°C. in a vacuum oven. The loss in
weight, about 90 per cent of the green weight, was taken to be total
moisture. The dried material was ground and reserved for further
study. )

TOTAL ACIDITY OF WATER EXTRACT

Several sound leaves with petioles, representative of the fresh
green material, were selected from each sample, and the weights of
the two charges recorded. In the case of the larger foliage two
leaves, weighing 43 gm., constituted the charge, while several leaves,
weighing in the aggregate 25 gm., represented the sample of smaller
foliage. Each charge was thoroughly macerated in a glass mortar,
and the resulting pulp transferred to a four-sided glass 8 oz. sample
jar, with exactly 200 cc. of distilled water, previously boiled and
cooled to room temperature. After violently stirring the mixture
for 30 minutes by means of an electric mixer,‘ it was thrown on dry
filter paper. The first (cloudy) portion of the filtrate was rejected,
and the total acidity in an aliquot of the clear extract was deter-
mined by titrating with N/1o sodium hydroxide solution, using
phenolphthalein as indicator. The presence in the water extract of
a natural indicator,’ the strongly darkening color of which tended
to obscure the end-point of the titration, made it necessary to carry
through concurrently a blank with a similar aliquot of extract with-
P 4 Described in Circular 68, Office of the Secretary, U.S. Department of Agricul-

ure,

5 This natural dye in the leaves of R. abyssinicus Jacq. appears pink in dilute
aqueous extracts of natural acidity. As titration with a fixed base progresses, the
color changes through yellow to brown, at about the neutral point, and the solution
becomes inky when made distinctly alkaline.

162 BOTANICAL GAZETTE [OCTOBER

out phenolphthalein. In this blank titration, the addition of N/10
sodium hydroxide solution kept pace with the quantity added in
the true titration, and the end-point was determined by contrasting
the colors of the titrated extracts. The extract containing phenol-
phthalein developed a noticeably redder brown color than the other.

In the computations allowance was made for the water present
in the green material. The total titrable acidity is expressed as
cubic centimeters of normal acid per kilogram of leaf material,
termed the ‘degree of acidity.”

SPECIFIC ACIDITY OF WATER EXTRACT

The specific acidity was estimated on a portion of the clear ex-
tract by a slight modification of the colorimetric method described
by GILLESPIE (3) after BARNETT and CHAPMAN (x1), in which use is
made of the principle introduced by CLARK and Luss (2), following
Sat (7), of “‘superimposing the two extreme colors of an indicator
in determining its half-transformation point.’’ Instead of using a
system of nine pairs of tubes having drop ratios 1:9, 2:8, etc.,
MEDALIA’s (4) system of seven pairs, having P,, exponent intervals
of o.2 between each pair for the indicators used, was adopted. For
convenience the procedure is briefly sketched here.

The color comparisons are made in the small ‘‘ block”’ compara-
tor described by GILLESPre. Seven pairs of test-tubes, selected to
fit the comparator and for their uniformity in bore, are calibrated
for 5 cc. capacity and arranged in a double row test-tube rack. A
total of eight drops of the suitable indicator solution is delivered
into each pair of tubes, 1 to 7 drops in the front seven tubes and
7 to 1 drops in the back row, care being taken to hold the delivery
pipette in an upright position. Sufficient alkali® (dilute acid in the
case of the indicator thymol blue, acid range) is then added to the
tubes in the front row to produce the full alkaline color, and suffi-
cient acid to develop the full acid color is added to those in the rear
row. ‘The tubes are then carefully filled to the 5 cc. mark with dis-
sero water, , previously boiled and cooled. Similar tubes are used
for the sol tion (the water extracts of the sorrel).
Licht dives of! the Jaticator solution are required, of course, and the

§ Quantity of alkali or acid varies somewhat for the different indicators.

1922] WALTON—AFRICAN SORREL 163

5 cc. volume is completed with the “unknown” solution. The
contents of all tubes are well mixed before making the color
comparisons. (Mixing may be accomplished by rolling the tube
back and forth between the palms of the hands.)

In making the color comparisons, the tubes, held vertically in
the comparator, are arranged in two files of three tubes each, one
file being made up of the tube containing the “unknown,” with
indicator solution and two tubes of distilled water, and the other
file consisting of a pair of the standard tubes and a tube containing
the “unknown” solution, without indicator. This arrangement is
necessary to obviate optical differences caused by thickness of liquid
viewed on the one hand, and on the other to offset the natural color
and any turbidity of the extract under examination. Different
pairs of standards are tried until the color of light passing hori-
zontally through that file of tubes matches the color from the file
containing the tube of ‘‘unknown,”’ with indicator.

As stated by GILtespiE, the tubes are viewed best against the
sky. Occasionally, in the case of certain indicators, such as brom-
phenol blue, trouble is experienced in matching the colors because
of a dichroic effect, especially noticeable in turbid solutions. In
such cases the tubes may be viewed by the yellow light of a carbon
electric lamp, screened as advised by CLARK and Luss. Only two
indicator solutions were needed in estimating the specific acidity
of the sorrel extracts, an 0.05 per cent aqueous solution of brom-
phenol blue,’ and an 0.02 per cent solution of thymol blue (thymol-
sulphonphthalein) in 80 per cent alcohol.

To develop the full acid and “alkaline” colors respectively, in
the standard paired tubes, the following quantities of reagents were
used for the two indicators:

Bromphenol blue-—To produce the acid color, 0.5 cc. of N/1o
hydrochloric acid solution; to produce the alkaline color, 1 drop of
N/zo sodium hydroxide solution.

Thymol blue (acid range).—To produce the full acid color, 2 cc.
of 1.25 per cent hydrochloric acid solution; to produce the color of

7 Tetrabromophenolsulphonphthalein. The 0.05 per cent solution was prepared
by diluting one volume of the indicator solution, furnished in the LaMotte field set,
to twenty volumes, with freshly boiled and cooled distilled water.

164 _ BOTANICAL GAZETTE [OCTOBER

the “alkaline” end of the range, 1 cc. of 0.005 per cent (N/700)
hydrochloric acid solution.

The volume in all the tubes should be made up at once to 5 cc.
The specific acidity values accepted for the several drop ratios are
given in table II. This specific acidity is based on the H-ion concen-
tration of pure neutral water as unity, as defined by WHERRY (10).
The articles by WHERRY and Apams (11) and CLark (11) discuss
this system of stating H-ion concentration.

TABLE II
SPECIFIC ACIDITY VALUES IN ROUND NUMBERS
BROMPHENOL BLUE THYMOL BLUE, ACID RANGE
Drop RATIO : se ha

Specific acidity 5 Specific acidity Py

» ry RE ea niabirts Nine ini Gea 6300 a4 400,000 1.4
oo 4000 3.4 250,000 1.6
yg Sue ee ere eae) Piak S) 2500 3.6 160,000 1.8
Pha Uae eR AV eer gah 1600 2.5 100,000 2.0
Lek ee Se Meg a mA I 4.0 63,000 2.2
Gites eon oes Lee 630 4.2 40,000 2.4
pt Sere Rey See era 4.4 25,000 2.6

These specific acidity (and P,) values, while not absolutely
exact, are close enough for the purposes of this investigation, particu-
larly as it was found that the specific acidity of the sorrel extracts
fell at the extreme acid end of the bromphenol blue series, or between
that and the “alkaline” end of the thymol blue, acid range, where a
close estimation is impossible.* The sorrel extracts, however, were
checked up by comparison with the straight acid color of the first
indicator and the straight “alkaline” end color of the thymol blue,
acid range.

The color standards are quite permanent, and if the tubes are
stoppered and kept in the dark they may be used over a long period
(4). The literature citations, particularly 3 and 4, contain details
on the use of indicators covering Py values from 1.2 to 9.8. Both
titrable and specific acidity were determined also on water

§ As stated by GILLESPIE, measurements cannot be accepted at the point where
the drop ratio is 9:1 or 1:9 (7:1 or 1:7), as the percentage transformation of the
indicator is so nearly roo or zero that the Ht exponent may be far from that repre-
sented by the ratio, and this would not be disclosed by a difference in color.

1922] _ WALTON—AFRICAN SORREL 165

extracts of dried and ground material of both samples. All deter-
minations were made at room temperature, 25°-30° C. The higher
temperature was usually reached in the afternoon during August.

TOTAL OXALATE

The estimation of total oxalate was undertaken for the purpose
of verifying the figures obtained in the acidity work, and a critical
study of oxalate methods was not attempted. After the completion
of this work, the writer’s attention was directed to a method, per-
fected by W. F. Kunke, Bureau of Chemistry, for the determina-
tion, with a high degree of accuracy, of the total oxalate content of
plant material. Using this method on another sample of the sorrel
foliage, KUNKE obtained materially lower figures than those reported
in this paper for total oxalate. Because of this and the relative
crudity of the usual method, the figures for total oxalate herein
reported are probably somewhat high. This, however, in no way
invalidates the data dependent on the acidity determinations (the
figures for potassium binoxalate), as whatever error there may have
been appears in the figures for calcium oxalate.

The total oxalate content was estimated only on the dried and
ground material. Two gm. was weighed into a 150 cc. volumetric
flask, about 100 cc. of 2 per cent hydrochloric acid solution added,
and the mixture, after being heated to boiling, was digested for
thirty minutes on the steam bath. After cooling and completing
the volume to 150 cc. with distilled water and mixing, the extract was
filtered through dry filter paper. The total oxalate in roo cc. of
the hydrochloric acid extract was estimated by precipitation with
calcium chloride and titration of the oxalate with standard solution
of potassium permanganate, in the usual way. Contamination of
the calcium oxalate precipitate with organic matter necessita
double precipitation, and the final precipitate was washed with
I per cent acetic acid solution in the cold, for further purification.®
Two control determinations on pure sodium oxalate were conducted
under the same conditions as those for the sorrel samples. In the
titration, which was carried through rapidly, there appeared to be a

9 Final gh aceegical ah calcium oxalate in acetic acid solution would be preferable
for a material of this na

166 BOTANICAL GAZETTE [OCTOBER

definite end-point, at which the pink color of the permanganate
persisted for an appreciable interval of time, although organic matter,
small amounts of which undoubtedly were present, continued slowly
to reduce additional permanganate.

Results .

The data obtained in the chemical examination of the fresh a
dried sorrel leaves are given in tables ITI, IV, and V.

TABLE III
ANALYSIS OF LEAVES OF Rumex abyssinicus
PERCENTAGE DEGREE OF ACIDITY | ppecentAGE TOTAL
S. : 1 acid
AMPLE ay in Ya (ce ae OXALATE AS (C:0.)*
Misc. Div. No. 38339, small le leaves
with petioles (fresh). . 90.77 162.7 1.69
Dried at 65°-70° C. and gr und. 2.99 1490.07 17.8
Misc. Div. No. 38340, large aa
with petioles (ir Oa ees) 89.59 185.4 78
Dried at 65°-70° C.and ground 2.50 1500.0 16.2
* As stated previously, according to KuNKE these figures may be somewhat high

+ Evidently there was a decrease in acidity during sary for the degrees of acidity as determined
on the dried material, computed to the original moisture bases, would be 141.8 and 160.2 respectively.

TABLE IV
WATER EXTRACT OF LEAVES
SPECIFIC ACIDITY, H-ION CONCENTRATION
OTAL
— ACIDITY IN Of {es oe solution of
sAMPLE .| 100 CC. OF | Of water extract of Rumex i
siceenae Pol EXTRACT een Ghee eg ren | acidity Pdike: as water
roo cc, | EXPRESSE extract e
or. | AS NORMAL assee (computed)
extract; ACID
(gm.) ) Specific P
Specific acidity Py soulieg 1H
No. 38339, small
leaves with petioles
(fresh) eee 11.26 1.72 | 6300-10,000 | 3.2-3.0 | gooo 3.05
WI i ci caca ee. 1.00 1.49 6300 2.3 8400 3-08
No. 38340, large
leaves with petioles
Oo oka ek: 18.07 3.35 |10,000-16,000] 3.0-2.8 | 12600 2.90
ee > I.00 I.50° 6300 2.2 8400 3.08

Fs ae
* The method of computation is discussed later under Discussion. Attention is directed to ~ haan’
agreement between the observed values and those computed for a pure potassium binoxalate solutio:

1922] WALTON—AFRICAN SORREL 167

Table IV gives the figures relating to the acidity of water extracts
of both the fresh and dried material, and specific acidity values
computed for pure solutions of potassium binoxalate of the same
respective normalities (titrable acidities) as the water extracts.

TABLE V
PERCENTAGE OF OXALATES AND EQUIVALENTS IN LEAVES
Calcium
bag wa (C20.) tal ( nf mn
minus ac
Sample on acidity of ge deren of Ria vaca se ) C20,), in | ves
water extract Rereilt table 111 column 4 equivalent
ae minus | of (C.0,) in
si omg column 3 preceding
column
No. 38339, small leaves
ee SSN. one a 1.82 1.25 1.69 0.44 0.64
Seer yy aa gks 19.09 13.10 17.80 4-70 6.80
No. “38840, large leaves
wn any Mos oe cas 2.05 1.41 1.73 0.32 0.47
EP MOn Say sian) Parte 19.22 13.20 16.20 3.00 4.40

The data in table V are derived entirely from determinations
made on the dried material. In the second and last columns the
data from tables III and IV are correlated to show the percentage
amounts of salts of oxalic acid presumably present in both the
fresh and dried leaves. The percentages given for calcium oxalate
are for the anhydrous salt, for convenience in comparing with data
in pharmacological literature.

The assumption that most of the oxalate is present as potassium
binoxalate and calcium oxalate (as the monohydrate) is substan-
tiated by additional information obtained through the kindness of
Dr. Wuerry. The work of Mr. DEvEL on total soluble oxalate
also checks in a striking manner the figures for binoxalate.

CRYSTALLOGRAPHIC-OPTICAL EXAMINATION

WuHERRY, who examined some of the dried and ground material
by polarized light, under a petrographic microscope, identified
humerous crystals of potassium binoxalate, and a smaller number
of crystals of calcium oxalate monohydrate in groups. The potas-
sium binoxalate crystals were readily identified, because of their
characteristic of having a relatively low alpha index. WHERRY

168 BOTANICAL GAZETTE [OCTOBER

states that four substances might conceivably be present in the
sample of plant tissue, and first determined their optical properties
as follows:

Alpha Beta | Gamma 2E. Sign
Oxalic acid milgdeate 556s cs vhs £idde |r, 805 | £cs40 120° i
Potassium binoxalate................ 1.415 | 1.545 | 1.565 65° =
Potassium oxalate monohydrate....... 1.440 | 1.485 | 1.550 160° “
Calcium oxalate monohydrate......... 1.490 | 1.555 | 1.650 |Over 180° 2

Examination of the sample showed two distinctly different
crystalline substances to be present, one in rosettes of acute crystals,
the other in nearly equant grains. The first proved to have the
refractive indices characteristic of calcium oxalate as indicated,
the second to have those of potassium binoxalate. The calcium
salt occurs as aggregates of crystals, and therefore looks more prom-
inent, but considering the large number of small grains of the potas-
sium salt which are scattered around, it is evident that the potassium
salt is present in the greater amount. Immersion liquids 1.490 and
1.565 are most suitable for distinguishing the two, the potassium
salt having one index much lower than the first, the calcium salt
one much greater than the second. As no crystals were found to
be present with gamma less than 1.560, or beta less than 1.540, it is
to be inferred that neither oxalic acid nor neutral potassium oxalate
is present, at least in significant amounts.

TOTAL DISSOLVED OXALATES

DEvEL has kindly consented to the inclusion in this paper of
figures obtained by him for the soluble oxalate in a sample of foliage
from the same group of plants from which these samples were ob-
tained. His procedure was to boil the finely minced leaves in water
for 1.5 hours, filter, make up the extract to definite volume, and in
an aliquot determine the total soluble oxalate gravimetrically by
precipitation as calcium oxalate, and after ignition, weighing a5
calcium oxid. In the two samples of foliage examined he found
oxalate equivalent to 2.06 and 1.96 per cent potassium binoxalate.
The percentage of moisture on the samples was not reported, but
the figures are for the fresh leaves.

1922] WALTON—AFRICAN SORREL 169

Discussion

Much may be learned about acid material of the same general
type as the foliage of Rumex sp., merely from a determination
of the total (or titrable) and the epeene acidity of a water
extract of it. By “same general type” is meant here acid material
in which, as in the sorrel, the “acidity” is due almost entirely to
forms of a single acid. If, in addition to total and specific acidity,
the total amount of the acid radical present in the water extract and
in the material itself be known, it is possible to draw fairly accurate
conclusions as to the quantities of the several salts of that acid
actually present, without making elaborate determinations of
the several basic elements. Auxiliary use of the petrographic
microscope may afford valuable qualitative substantiation of the
conclusions.

In this investigation the mere determination of “degree of
acidity’’ (total titrable acidity of the water extract) of the sorrel
foliage meant little; the acidity might have been caused by the
presence of free oxalic acid. Determination of the specific acidity
(H-ion concentration), however, proved conclusively that the
acidity of the water solution could not have been caused by the
presence of the free acid; as for the normality involved, the spe-
cific acidity value of oxalic acid would have been approximately
ten times” the values actually found. On the other hand, the
agreement between the “specific acidity’’ values determined experi-
mentally for the sorrel extracts and those computed for pure solu-
tions of potassium binoxalate of the same normality is striking.
These values for potassium binoxalate solutions were computed by
K Y) .

the help of the formula: Percentage ionization = 100( V KV-

%° Computed from data reported by Tuomas (9) after Ostwatp (5). Oxalic acid
of a dilution comparable with the water extract of sample No. 38339 (N Xo0.0172) is
highly dissociated, the percentage ionized being 88.4 at 25° C., according to Tuomas’
table.

* By an evident typographical error this formula in Tuomas’ article was incor-

aoe 4
rectly stated: “Per cent ionization=100V K oe ” The method of calculating
the Px value is here appended in more detail, using as an example the data for the
nat =. b &; , ‘2s 3: 4 re - 4 £4 7 g 7 Noi i.

170 BOTANICAL GAZETTE [OCTOBER

derived from OsTWALp’s dilution law, as explained in detail by
THomAs (9). In this formula V =the volume in liters, in which one
gram molecular weight of the substance is dissolved, and K =the
dissociation constant. The values used for K are those given in
SCUDDER’s (8) tables, and are for 25° C.

The data from the acidity determinations, therefore, point to
potassium binoxalate as the sole source of the acidity of the sorrel
extracts, at least of those of the dried material. Furthermore, a
calculation of the percentages of this salt present in the samples
based on the titrable “acid” in the extracts of the dried leaves yields
figures agreeing very closely with those obtained by DEvEt for the
oxalate (as potassium binoxalate) dissolved by boiling water.

These data, per se, do not preclude the possibility of the presence
in the foliage of approximately equivalent quantities of free oxalic
acid and normal potassium oxalate, which would simulate the acid
salt, and, in fact, in aqueous solution would be identical with it.
WHERRY’s observations on the dried material decides the point
beyond a doubt. ‘The acid nature of the leaves is unquestionably
due to the presence of potassium binoxalate.

On recalculating the figures obtained for titrable acidity in the
dried material (on which are based the figures for potassium binoxa-
late in the leaves) to the original (green) moisture bases, it becomes
apparent that there is a loss of titrable acid during the drying.
These figures (footnote, table III) become 141.8 and 160.2 for
“degrees of acidity” on the original bases, respectively equivalent
to 1.82 and 2.05 per cent potassium binoxalate, while the acidity
actually titrated in the fresh material yielded the figures 152.7 and
185.4 (in terms of potassium binoxalate corresponding to 1.96 and
2.38 per cent); therefore 10.9 and 25.2 cc. respectively of normal
acid per kilogram of fresh leaves disappeared during the drying of
the two samples. This lost “acid” may have been carbon dioxide
or other weak volatile acids, or may be accounted for in part by
changes in colloidal, acid-reacting protein. The discussion by

ity of solution=0.0335 VN; hence V=29.85, K=4.9X10—5. Percentage ionization=
3-75+- H per liter=0.0335X1.008 gm. H™ per liter=0.0375X0.0335 X1.008=
0.001267 = 1.267 X10—3 .*. Pa=algebraic sum of —3, and log. 1.267=—2.897. Omit-
ting the negative sign, Pa=2.9 (specific acidity = 12670).

1922| WALTON—AFRICAN SORREL 27%

PFEFFER (6) of decrease in acidity in plant tissues (in life) and in
sap, due to a rise in temperature (from 15° to 45°) and to exposure
to sunlight, fully explains a loss in acidity of this magnitude, on
drying fresh material in which the cells are still functioning.

From the figures obtained for total oxalate it becomes apparent
that there is more oxalate present in the leaves than is accounted
for by the potassium binoxalate. Further, this excess oxalate
must be either insoluble or neutral in reaction if soluble. Again
the crystallographic-optical examination made by WHERRY decides
the point. The only normal oxalate found was the insoluble calcium
salt. A recapitulation of analytical results is presented in table VI.

TABLE VI
ANALYSIS OF LEAVES OF Rumex abyssinicus
bs, ta;
Percentage cromte calcium . Degree of acidity
Leaves : = at bacaicinkis oc to o (ec. hoe gia
_ ot aies ate
EY hg (HKC.0,) (Ca C.0,. H.0 HO)
Smaller << (fresh). ou 90.77 1.82 0.73 £529
Larger leaves (fresh). . 89.50 2.05 0.53 185.4
Smaller waa (after drying). 2.99 19.09 7.80 1490.0
Larger leaves (after drying). 2.50 19.22 4.98 1500.0

A discussion of the influence of such quantities of oxalate on the
edibility of the sorrel foliage, or of the physiological effects following
its use as food, is outside the scope of this paper.

Summary

1. The study here reported of the acidity and oxalate content of
the leaves of Rumex abyssinicus (an African sorrel) demonstrates
the advantages of determining the specific acidity (H* concentra-
tion), as well as the total (titrable) acidity of a water extract of acid
material of this nature.

2. This paper brings together descriptions of relatively simple
procedures, worked out by the investigators cited, for (1) colori-
metrically determining, without the use of buffer solutions, the
specific acidity of such water extracts, and (2) computing, for pur-
poses of comparison, the specific acidity and P; value of pure solu-
tions of the acid substance suspected of being the source of the

172 BOTANICAL GAZETTE [OCTOBER

acidity. Through a comparison of these values, matching the
specific acidity actually determined against that computed for those
substances causing the acidity, a means of identifying, or at least
indicating, the principal source of the acidity is described.

3. The data indicate that only two compounds of oxalic acid,
potassium binoxalate and calcium oxalate monohydrate, occur in
the Rumex leaves examined. The percentages in which these salts
occur are computed from the data for paints and total oxalate in
the dried material.

4. Attention is directed to the value of a crystallographic ex-
amination in corroborating the results of the chemical work. It is
believed that the scheme of investigation described should prove of
value to analysts in examining drugs, foods, or feeding stuffs of an
acid character.

5. The presence of a natural indicator in the leaves of R. abys-
sinicus, the aqueous solutions of which are pink in the natural acid
solution, is noted. On adding a fixed alkali the solution changes its
color through yellow to brown, becoming nearly black when dis-
tinctly alkaline.

The writer wishes to thank Mr. Paut G. Russet of the Office
of Foreign Seed and Plant Introduction for making examination of
this material possible, for furnishing information as to the history
of the plant and its culture in this locality, and for providing the
fresh foliage for analysis. Also acknowledgment is due Messrs.
Deve and Kunke for their kindness in permitting the inclusion of
notes of their work, and Dr. Wuerry for his helpful suggestions
and for the crystallographic examination of the leaf material.

BurREAU OF CHEMISTRY
Wasaincton, D.C,

LITERATURE CITED

1. BARNETT, G. D., and Cuapman, H. S., Colorimetric determination of reac-
tion of bacteriologic mediums and other fluids. Jour. Amer. Med. Assoc.
70:1062. 1918.

2. CLARK, W. M., and Luss, H. A., The colorimetric determination of
hydrogen-ion concentration and its application in bacteriology. Jour.
Bact. 221-34, 109-136, 191-236. 1917.

1922] WALTON—AFRICAN SORREL 73

3- GILLEsPrE, L. J., Colorimetric determination of hydrogen-ion concentration
Soi

without buffer mixtures, with especial reference to soils. Soil Science
Q:115. 1920,

. Mepa ta, L. S., “Color standards” for the colorimetric measurement of

hydrogen-ion concentration Py 1.2 to Pag.8. Jour. Bact. 5:441. 1920.

. Ostwarp, W., er die Affinitatsgréssen organischer Séuren und ihre

Beziehungen zur zusammensetzung und Konstitution derselben. Zeit.
Physik. Chem. 3:281. 1880.

. PrerFEeR, W., The physiology of plants. Vol. 1. pp. 328, 329. trans. by

Ewart, A. J., 2d ed. Oxford. 1900

. SALM, E., Studie iiber Indikatoren. Zeit. Physik. Chem. 57:471. 1906.

ScuppER, H., Conductivity and ionization constants of organic compounds.
New York: Van Nostrand Co. 1914.

Tuomas, A. W., Tabulation of hydrogen and hydroxy] ion concentrations
Be some acids pr bases. Jour. Amer. Leather Chem. Assoc. 15:133-146.

10. Gare E. T., Soil acidity and a field method for its measurement.

Ecology 1:160. 1920.

tr. WueERry, E. T., and Apams, E. Q. (and reply by CLarK, W. M.), Methods

of stating acidity. Jour. Wash. Acad. Sci. 112197. 1921.

MICROBIOLOGY OF FLAX RETTING
FRED W. TANNER

Linum usitatissimum has been cultivated for thousands of years
as a textile fiber producing plant. The Egyptians must have raised
it, since their mummies are found today wrapped in fine linen.
Frequent allusions to flax and linen in the Bible indicate that the
ancients were acquainted with the usefulness of the bast fibers in
flax and had methods of separating them from the rest of the plant.
They were also familiar with other types of fibers, since these are
found in their papyri today. The United States cannot be regarded
as a great flax or linen producing country; it has had to depend
mainly on importation to supply the increasing demands for linen.
In the spinning of flax the United States was at the bottom of the
list of the larger countries in 1915, with slightly over 8000 spindles
against Great Britain’s 1,161,000." Most of these were in Ireland,
although they were not kept busy on fiber produced in Ireland.
Russia was once the largest flax fiber producing country, contribut-
ing 80 per cent of the flax fiber used in making linen. Since the
world war, however, this has changed on account of the industrial
disorganization in that country. Statements in the press, said to
come from the Office of Fiber Investigation of the United States
Department of Agriculture, indicate that the spinning mills in this
country have used about 10,000 pounds of flax fiber per annum.
For the production of this amount of fiber about 60,000 acres of
land would be required. In 1920 only 6000 acres of flax were
grown in this country, while the low price paid for it will restrict
the acreage to about 3000 in the future.

Flax is raised in this country mostly for seed which is pressed
for linseed oil; a smaller amount is raised for the fiber. Flax
raised for seed is of a different quality from that usually required
for fiber. Fiber flax is taller and produces less seed. It requires
greater care in cultivation, and especially careful handling at the

* Mites, C. F., Fiber flax. U.S. Dept. Agric. Farmer’s Bull. no. 669. 1915-
Botanical Gazette, vol. 74] [174

1922] TANNER—FLAX RETTING 175

harvest. Some claim that it must be pulled, not cut, and tied up
carefully in bundles. This may be one reason why it has been
difficult to utilize the flax from seed flax for spinning. It might
be possible in the future to combine profitably the seed and fiber
crop. This would tend to reduce the value of each crop taken by
itself perhaps, but the value of the combined crops of seed and
fiber might compensate for any decrease in the value of the single
crop.

The bast fibers, which are those used in making linen, are
cemented to the other parts of the stalk and to each other by means
of materials, for convenience, called pectins. Undoubtedly this term
is used only in a general way to cover a number of compounds
closely related chemically. The aim of the retting process is to
remove these “binders”? without harming the cellulose fiber. The
fermentation must be checked when these fibers have been freed
by the hydrolysis of the pectose or salts of pectic acid. These
binding materials which hold the stalk together are undoubtedly
carbohydrate in nature, and thus susceptible to the action of
microoganisms.

Preparation of flax fiber

The fiber is prepared from the flax straw by a special process
which seems to have been built up after a long period of time with-
out much assistance from the sciences. Proper harvesting is very
important. Fiber flax should be pulled either by hand or by
machinery and tied into bundles which are shocked for curing.
Cutting the flax is claimed by some to leave the ends of the stalk
exposed for undesirable decompositions. When the heads are
shocked for curing, this cut end becomes susceptible to the attacks
of undesirable bacteria. The fibers become badly stained also.
This may not be entirely true, however, under actual practice.

After curing, the stalks are retted. This is really a rotting
process, which indicates the origin of our present term. Three
general methods may be used to dissolve the binder which holds the
cellulose fibers to the woody materials: dew retting, water retting,
and chemical retting. The first two only are of bacteriological
interest, and were studied in the present investigation.

176 BOTANICAL GAZETTE [OCTOBER

Dew retting was used by our forefathers in this country for
preparing flax fiber for spinning. It represents the earliest method
of preparing flax fiber. No special apparatus is needed, since the
flax straw is merely spread on the ground in the fall and allowed to
remain throughout the winter. Dew retting has been used for the
preparation of most Russian flax fiber. Its greatest objection is the
time required, but this may be reduced greatly by carrying the
process out under conditions where the retting organisms may be
made to work harder.

Water retting was introduced undoubtedly to get away from
certain of the distinct disadvantages of dew retting. It is carried
out either in slow flowing rivers or in ponds and other inclosed
bodies of water. The bundles of flax straw are packed into these
basins and weighted down. The retting process starts with a gase-
ous fermentation of the carbohydrate materials in the flax straw.
If conditions are favorable, a little over ten days is necessary for
the completion of the fermentation. The flax should be removed
when all the pectic materials are dissolved, or over-retting will
result. The bundles are removed, dried in sun and air, and are
then ready for scutching. The river Lys in Belgium is famous for
its flax retting. River retting has certain economic features which
limit its wide application. As KUHNERT? has shown, the stream
becomes putrescible, which is detrimental to fish life. It carries
amounts of organic materials in the reduced conditions which may
give off objectionable odors. Water retting has not had wide
application in this country.

Several attempts have been made to improve on the water
retting. One of the earliest of these was proposed by SCHENCK in
1846. ‘The flax straw was packed tightly into a tank and the water
kept at a temperature of 75°-95° F. This warm environment was
more favorable to the development of the bacteria concerned in
this process, and a vigorous fermentation quickly established itself.
The vats had all of the characteristics of a fermentation mixture.
Others have proposed similar methods with a higher temperature.

Scutching is the process by which the woody material is broken
away from the cellulose fibers after they have been retted and

? KUHNERT, Landw. Wochenbl. Schleswig-Holstein 70:540-543. 1920.

1922] TANNER—FLAX RETTING 177

dried. Different methods have been used, all of which rest on
breaking the woody particles and mechanically removing them from
the stalk. The fibers are finally combed to separate the “tow”
from the fibers which are not long enough to remain in line. The
latter may be used in paper, coarse linen, etc. The fiber from flax
may be 30-40 inches in length, thus yielding a product which is
valuable for spinning.
Microbiology of retting

Retting is indeed a natural process, and may be regarded as
merely a step in the cycles of the elements. The various factors
involved have been separated in an attempt to intensify certain
ones in order to make the process shorter, and also to produce a
better fiber. In retting flax man has simply made use of and intensi-
fied a reaction which is always going on.

One of the first investigations on the microbiology of retting
was carried out by, VAN TIEGHEM in 1879, in his study of the process
of water retting. An anaerobic organism named Bacillus amylo-
bacter was reported as the organism which quickly decomposed the
pectic materials of the flax stalk. In the same year VAN TIEGHEM
stated that his Bacillus amylobacter was probably identical with the
Vibrion butyrique. An aerobic spore-forming organism was also
found by Wrnocrapsky.’ Frises, working in this laboratory,
tried various disinfectants for sterilizing the flax, but finally used
the method of heating in water at 100° C. for three successive days,
or at 115°C. for fifteen minutes. Various aerobes and anaerobes
were isolated, none of which seemed to have any effects on the flax.
Finally a specific anaerobe was isolated. It was a spore-former,
the young cells of which were tou to 154 by 0.8u. Glucose, sucrose,
starch, and lactose were fermented if some nitrogenous matter was
present. A quite similar microorganism was also isolated by
BEHRENS® from the water retting of hemp. The organism was a
Clostridium form fermenting the binding materials of hemp straw.

3vaN TreGHEM, Sur la fermentation de la cellulose. Bull. Soc. Bot. France
26:25. 18709.

4 Wrnocrapsky, S., Sur le rouissage du lin et son agent Microbien. Comp.
Rend. Acad. Sci. 121:742. 1895.

5 BEHRENS, J., Cent. Bakt. 10:524. 1903.

178 BOTANICAL GAZETTE [OCTOBER

It fermented glucose, sucrose, fructose, lactose, galactose, and
starch with abundant gas formation, but could not attack arabinose,
cellulose, gum arabic, or calcium lactate. Similar to WINo-
GRADSKY’S organism, it required some source of nitrogen, as pep-
tones or proteins. It was an obligate anaerobe with large spores
which had a greater diameter than the vegetative rod.

In 1902 HAuMANN® published an interesting paper which gave
an entirely new aspect to the subject. He stated that many
common microorganisms could ret flax. He first studied the flora
on the stalks of retted flax and isolated a number of organisms,
among which were Bacterium coli-communis, Pseudomonas fluorescens,
Bacillus subtilis, Streptothrix Forsteri, Penicillum glaucum, Cladospo-
rium herbarum, Bacillus mesentericus fuscus, B. mycoides, B. termo,
Micrococcus roseus, and Mucor mucedo. The mere presence of
these organisms would not indicate that they functioned in retting.
The preponderance of certain species, however, might indicate
some relation to the retting process. Cladosporium herbarum,
Bacillus mesentericus, B. subtilis, and colonies of Streptothrix were
common. ‘To determine whether these organisms were important,
HAUMANN inoculated sterile flax with pure cultures. The flax
stalks were put into long culture tubes plugged with cotton. The
tubes containing flax were heated to temperatures below 110° C.
in the dry condition. He stated that three heatings under such
conditions did not alter the flax. Retting was accomplished by
using many of the common species of microorganisms. There was
a difference in action, Pseudomonas fluorescens giving good results,
while Micrococcus roseus was least satisfactory. HAUMANN con-
cluded from this that all of the common bacteria were able to ret
flax. Some of these bacteria were also able to split pectin. His
results are unique in that they contradict those secured by many
others and also those obtained in this investigation. In the light
of some of the recent work on thermal resistance of the spores of
anaerobic bacilli, HAuMANN’s method of sterilizing the flax is open
to criticism. One would not expect these spores to be destroyed
by a temperature of 110°, especially in the dry conditions. It is

6 HaumANN, M. L., Etude microbiologique et chimique du rouissage aerobic
du lin. hak ‘Past. Tost, 16:378-385. 1902.

1922] TANNER—FLAX RETTING 179

possible that some of the spores of anaerobic bacteria survived and
produced the characteristic change in the flax fiber which was
attributed to the pure culture of aerobes used.

An anaerobic organism was also found by BrEIyERINCK and
VAN DELDEN,’ to which they gave the name Granulobacter pectino-
vorum. ‘This organism was an obligate anaerobe and a vigorous
spore-former. It required protein or its split products as sources
of nitrogen, liquefied gelatin, and actively attacked carbohydrates.
In general it had the characteristics of the anaerobes described by
others, especially the one found by WrNoGRADSKY.

more recent extensive investigation has been reported by
STORMER,® who found an anaerobic spore-former which he called
Plectridium pectinovorum. The granular structure of the cells
makes one believe that he had the organism described by earlier
writers. STORMER’s bacillus seemed to differ from these, however,
in being a facultative anaerobic organism.

In sharp contrast with these papers are a number of others
indicating that an aerobic organism is involved. MaARMIER? men-
tioned such an organism. BEIJERINCK and VAN DELDEN also
reported that Bacillus subtilis and B. meseniericus would ret flax,
although they found another organism, which they called Granulo-
bacter pectinovorum, which seemed to ret flax more completely and
quickly.

Rossr® studied the retting of vegetable fibers and stated that
the microbiological retting process has certain advantages over
chemical retting. Whether this is true or not is probably deter-
mined by the uses to which the fiber will be put. He devised an
aerobic method in which Bacillus comesii was allowed to act on
material which had been steeped in water at from 28° to 35° C.
The pure culture was added and the vat was aerated, the tempera-

7 BEIJERINCK, M. W., and vaN DELDEN, A., Over de bacterien welke bij roten
van vlas werksdam zign. Kon. Ak. Wetensch. Amsterdam (Verstag. van de Gewone
Vergadering der Wis en Natunkk) 12:673. 1903.

§ Stormer, K., Uber die Wasserroste des Flachses. Chem. Zent. 76:41. 1905.

9 MarmieER, Le rouissage du lin. Bot. Centrabl. 83:90. 1900.

* Rosst, G., Industrial retting of textile plants by microbiological action. Bull.
Agric. Intell. 8: solkania: 3 g16.

180 BOTANICAL GAZETTE [OCTOBER

ture being maintained between the extremes just mentioned, since
the fermentation goes on most vigorously at that range. Rossi’s
work was concerned with hemp, but the organisms may be similar
to those used with flax. An anonymous article in the Bulletin
Imperial Institute (17:605-607. 1919) confirms the work of Rosst.
Flax straw is immersed in water at 82° to 86° F. in vats, and after
the addition of a special aerobic organism, B. comesii, it is aerated
during the retting process. The pectinous materials are consumed
and the retting process is completed in 36-40 hours. Another
aerobic organism called Bacillus felsineus is reported which will
also ret hemp, flax, ramie, nettle, and other plants. It is said to
produce a rapid retting and furnish a fine, white, well separated
fiber. Lorser,™ in carrying out Rosst’s process, boiled flax for
forty minutes and then treated it with pure cultures of Bacillus
comesit. The vats were aerated and maintained at a temperature
of 30°-32°C. These methods are more expensive than those which
do not require boiling. Furthermore, the anaerobic organisms are
so resistant to heat that they might pass through these preheating
procedures and function in retting the flax, although the credit be
given to certain aerobic bacteria.

Corrican® has more recently discussed the relation of fungi
to retting. His statements apparently are based on the researches
which have been reviewed herein. Mrs. Wyant has recently
reported briefly some results on this problem. She isolated about
forty cultures of both aerobes and anaerobes. Each of these
cultures was tested for its retting ability. This narrowed the work
down to one pure culture which received more intensive study.

Experimental work

The work which has been carried out at this laboratory has
been done with pure cultures, and on materials from a large rettery

*t LogsER, R., Retting of flax by fbacteria. Jour. Soc. Chem. Ind. 38:407-
IgIQ.

t CORRIGAN, J. FREDERICK, Bacteria and molds: their biological nature and
their influence on vegetable fibers. Jour. Soc. Dyers Colourists 36:198-201. 1920-

"3 Wyant, Z. N., Some bacteriological problems involved in the retting of flax.
Abstracts Bact. §:208, 209. 1921.

1922] TANNER—FLAX RETTING 181

in eastern Michigan.** Most of the flax used in these experiments
was grown in Michigan, and was thoroughly cured before it was
received at the laboratory. It was tied in bundles or “heads”’
and was in fine condition, since it had been cultivated for fiber.
The other was the flax which had been raised for seed, and con-
sequently had not been kept tied in bundles, but had become
badly broken and bent during thrashing. While just as good
retting was secured on this as with the stalks which were raised for
the fiber and tied in bundles, the resulting fiber was not of good
quality. Perhaps such a raw material could be better retted by
the chemical process. The fibers were much shorter, but probably
just as satisfactory for paper making.

The samples from the retting vats were taken in sterile bottles
and subjected to the usual bacteriological examination. Both
aerobic and anaerobic platés were made, from which pure cultures
were picked and transplanted into various culture media. The
flora from the vats was varied, but spore-forming bacteria of both
aerobic and anaerobic types werecommon. ‘The aerobic types were
similar to the members of the subtilis-mesentericus group; they
formed large spreading colonies on solid media and liquefied gelatin
very rapidly. Spores were easily formed in large numbers.

The pure culture experiments were carried out with many of
the common bacteria and several cultures of yeasts. The bacteria
and yeasts used were:

Pseudomonas pyocyaneus Saccharomyces cerevisiae
Proteus vulgaris Torula monosa
Erythrobacterium prodigiosus Saccharomyces ellipsoideus
ey es Saccharomyces marxianus

Zopfii Zenker Myoderma vini

Bacterium abeitidie Bacterium cloacae

Bacillus gasoformans Bacillus cereus

Bacterium colon Bacterium capsulatum
Bacillus butyricus Erythrobacillus arborescens
Bacterium aerogenes Bacillus subtilis

™4 The author is indebted to Mr. B. S. Summers of the Summers Linen Company
of Port Huron, Michigan, for material upon which some of the results here reported
were secured, and for his constant interest in the progress of the work. Dr. R. E
Finprusz of the American Writing Paper Company kindly furnished some flax straw
and exhibited a kindly interest.

182 BOTANICAL GAZETTE [OCTOBER

Contrary to the statements of HauMANN, successful retting
could not be accomplished with these common bacteria. None of
the organisms such as Bacillus subtilis was found to possess any
activity. In order to test the retting ability of all these cultures
and those isolated from vat liquors, flax straw was cut into pieces
about 4.5 inches long. These were put into long test tubes and
covered with water. Sterilization was accomplished by heating
in the autoclave at 115°C. for fifteen minutes. The sterility of
these flax straw culture tubes was determined by both aerobic and
anaerobic cultures in sterile litmus milk and other media. Heat-
ing in the autoclave at 115° C. seemed to be sufficient for their
sterilization, and did not seem to injure the straw or make the
retting more quickly accomplished when the bacteria were applied.
Experiments were carried out later in 3 gallon earthenware jars
in order to test the retting activity of the organism which was
finally isolated. Attempts were also made to find an aerobic
organism such as was used by Rossi. Flax straw was put into a
large glass vat covered with distilled water and aerated for a week,
with frequent examinations for aerobic pectin fermenting organ-
isms."* No success was obtained, even after specimens of soil and
decaying organic matter were added. Several workers have men-
tioned the use of aerobic strains. One who is familiar with bacterial
metabolism would expect to find an anaerobic organism. Members
of this group decompose more materials than aerobes which leave
so much energy in their products. The anaerobes partially hydro-
lyze large amounts of material for a certain amount of energy,
while the aerobes hydrolyze a smaller amount of material completely
for the same amount of energy. Perhaps for the same reason the
anaerobes are used in most of the fermentations which yield certain
organic chemicals.

The study of the vat liquors from a large Shoeiee rettery in
eastern Michigan, and from the specimens of flax and retting
liquors in small tubs in the laboratory, narrowed down to an anae-
robic organism as the most specific. This was secured in pure
cultures by anaerobic plating in plain agar. Transfers made into
other media allowed the following characterization:

% Industrial retting of textile plants by microbiological action. Bull. Agric.
Intell. 8:1067—-1074.

1922] TANNER—FLAX RETTING 183

Vegetative cells: The vegetative cells grown on common media
were large rods with a dense protoplasm. Many of the cells pre-
sented a granular structure. Iodine staining indicated the presence
of starchy materials.

Spores.—Spores are formed which are larger than the vegeta-
tive cells, giving the cells the shape of a Clostridium. The spores
were found to resist heating for thirty minutes at 80°C. Further
studies on their thermal resistance seemed uncalled for in a study
of this nature.

FERMENTATION REACTIONS.—Large amounts of gas were formed
in lactose, glucose, saccharose, and glycerol. In most of these
fermentation tubes there was a pronounced odor of butyric acid.

ITMUS MILK.—Litmus milk was quickly decomposed; the
curd was peptonized with large amounts of organic acids, princi-
pally butyric.

GELATIN.—Gelatin was quickly liquefied at 20° C.

PLAIN BROTH.—The broth was rendered cloudy with a pre-
cipitate only after a long period of growth.

Nirrates.—Nitrates were reduced with the formation of nitrites
and ammonia.

That this anaerobic organism is common in nature and on the
stalks of the flax plant was shown in several ways. It was found
to be present repeatedly on the stalk of flax by simply soaking it
in distilled water. After about thirty hours a vigorous evolution
of gas would start, which ceased in about forty-eight hours at room
temperature. This could be reproduced at will. That the organ-
ism is present in soil was shown by adding garden soil to tubes of
sterile flax in distilled water. All evidences of a rapid retting
started in twenty-five hours, and was completed in forty-eight
hours. Pure cultures of this anaerobe removed the carbohydrate
binders in the flax stalk in forty-eight hours at room temperature
(26°-32° C.). The fermentation is accompanied by a vigorous
evolution of gas, which is forced out of the stalk, clinging to the
side until the bubble is large or some jar removes it. The liquid
becomes turbid and has a strong characteristic odor.

Whether pure cultures of this anaerobe would be valuable in
retting is probably doubtful, since the organism is so widely
tributed in nature. Several experiments were carried out to deter-

184 BOTANICAL GAZETTE [OCTOBER

mine whether the organisms were on the flax stalk itself. There
was no difficulty in the majority of attempts to demonstrate its
presence. In a large sense the change brought about in the flax
stalk is a natural one, which is continually going on in nature. It
is an attempt on the part of nature to bring about the transforma-
tion of organic compounds, and to keep the elements moving
through their cycles. In retting it is the desire to carry this to the
point when the binding materials in the fiber are dissolved, thus
releasing the bast fibers, and to check it just before the cellulose
of the fibers is attacked. It is reasonable to expect that this could
be done more quickly in a rettery, where favorable conditions are
maintained and where the flora of microorganisms may easily be
established.

The quality of the water seems to have great influence on the
quality of fiber. During a few experiments in the beginning of
this work tap water containing about 1 p.p.m. of iron was used.
This yielded a fiber which was dark and discolored in appearance.
The use of pure distilled water corrected this and yielded a silken
glossy fiber nearly white in color. This supports the experience
in water retting that a better fiber is secured where a softer water
is available, and confirms the statements of workers that the
quality of fiber produced in the Courtrai region in Belgium, where
flax is retted in the waters of the river Lys, is superior to that retted
elsewhere.

One of the earlier investigators stated that the presence of
aerobic bacteria tended to produce more favorable conditions in
which the anaerobic could act. To determine whether there was
foundation for this, several experiments were carried out with
mixtures of the anaerobe isolated in this investigation and certain
common aerobes. Bacillus subtilis and Bacterium coli were used,
but it could not be seen that they were of any value. Neither did
they seem to lengthen or shorten the time required for completion
of the retting process. Their presence seemed to have little effect.
Under natural conditions they might favor the retting in that they
would help to remove the products formed from the pectic binding
materials. In favor of this assumption is the fact that nature does
most of her work with mixed cultures, and many significant changes
are brought about by symbioses.

1922] TANNER—FLAX RETTING 185

Summary and conclusions

1. Retting of flax in the preparation of linen fiber is a natural
process, and an attempt on nature’s part to keep the elements
moving through their cycles.

2. The organism isolated as the specific one in retting flax was
Clostridium amylobacter. It is an anaerobic spore-forming bac-
terium which quickly hydrolyzes the carbohydrate “binders” in
the flax stalk. It was found to be commonly present on flax stalks
and widely distributed in nature.

3. Symbiosis of this organism with common aerobic bacteria
did not seem to decrease the time required for retting or produce
conditions under which the anaerobic Clostridium amylobacter could
work better.

4. Temperature is an important factor in that it retards or
increases the activity of the fermentation involved in retting. The
best temperature seemed to be 30° C.

5. The retting process can be shortened and a better quality of
fiber produced by carrying it out under controlled conditions where
the optimum environment may be maintained.

6. Previous sterilization of the flax did not seem to affect the
retting process. The flax retted as quickly when put into the
water without previous treatment as when it was boiled or heated
in the autoclave.

7. No real success was vee by the use of fifteen common
aerobic bacteria and five yeastlike fungi

8. Flax raised for seed was salnsdy: retted, although the fiber
was not in as good condition as that prepared from flax raised for
fiber.

UNIVERSITY oF ILLINOIS
~ Ursana, IL.

ANATOMY OF A GALL ON POPULUS TRICHOCARPA
Kart C. Hype
(WITH PLATE VI)

Early in the fall of 1919 the writer collected some galls upon the
twigs of Populus trichocarpa T. and G., caused by Macrophoma
tumefaciens Shear,’ in Greenough Park, Missoula, Montana. ‘These
galls were relatively large woody growths, and appeared on the trees
in great numbers. Within an area of about one acre, at the north
edge of the park, there were as many as twenty-five trees of various
sizes bearing galls, while the trees throughout the rest of the park
were practically free from knots. A close examination of the
infected trees showed that nearly every twig bore from one to many
galls, and that above these galls in many cases the twigs were
gradually dying. The disease, although apparently occurring only
in isolated localities, appeared to the writer to merit further investi-
gation, and accordingly the problem was attacked at such an angle
as to show, if possible, what effect the fungus had upon the normal
twig to bring about the hypertrophy resulting in the gall.

Introduction

Populus trichocarpa is the largest tree of the genus, sometimes
attaining a height of 65 m. and a diameter of 2.6m. It is a rapid
grower, and is usually found in the lowlands. It is very common
throughout the Pacific coast region along the banks of streams, from
southern Alaska to northern California, extending as far east as the
ontinental divide in Montana. In Washington, Oregon, and east-
ern Montana it is the largest of the broad-leaved trees, tending to
break somewhat the monotony of the vast stretches of coniferous
forests of the region in its range. The tree is widely used for shade
and ornament for parkings and lawns of the cities of the northwest.
In Missoula, for example, there are many trees of this species within
the limits of the city. It is especially adaptable for regions of light

t Hupert, E. E., A new Macrophoma on galls of Populus trichocarpa. Phytopath.
5:182. figs. 3. 19
Botanical pas vol. 74] [186

1922] ‘HYDE—GALL ON POPULUS 187

rainfall because of its long roots and ease of propagation. The roots
were formerly used by the Indians of California and Oregon in the
manufacture of hats, baskets, mats, and other ornaments, being well
adapted for this purpose because of their toughness, fineness, and
length. The wood is dull brown, with nearly white sapwood, soft,
light, and weak, with a specific gravity of 0.38. It shrinks moder-
ately, warps considerably, is easily worked, but is not durable. It
has a dull silky lustre, and is used extensively for cooperage, boxes,
tubs, bowls, canoes, wooden legs, and paper pulp.

The only published work that treats of this gall is that of
HvuBERT, who deals with the characteristics of the fungus which is
thought to be the cause of the gall. He originally found the galls
on twigs of Populus trichocarpa in 1909, and at first thought they
were caused by an insect, Saperde populnea L. In March 1910
another collection was made, and he identified the causative organ-
ism as a species of Macrophoma, but was unable to determine its
specific identity. In November 1910 he sent samples of the galls to
C. L. SHEAR, United States Bureau of Plant Industry, who described
and named the fungus Macrophoma tumefaciens.

According to HuBERT, the fungus and galls are widely distributed
throughout Montana on the twigs of Populus trichocarpa. The
several cities mentioned as localities in which he has observed the
galls show that they occur at least throughout the western part of
Montana and the eastern part of Idaho.

Method

As the xylem of the normal wood is comparatively soft, no
difficulty was experienced in obtaining satisfactory sections.
Sections of the galls were made with a sliding microtome because
they were more uniform in thickness, and good photomicrographs
could be secured more readily. First the knots were cut into cubes
of suitable size for clamping into the microtome. These cubes were
then placed in a mixture of equal parts of glycerine, alcohol (95
per cent), and water, and heated for one hour at a temperature of
100° C. This treatment served the double purpose of softening the
wood and of removing a considerable amount of air. All of the air,
however, was not eliminated by this process, and it was necessary

188 BOTANICAL GAZETTE [OCTOBER

to use the airpump to remove entirely the air from the blocks.
Sections 10 yw in thickness were easily obtained by these methods.
In staining sections it was found that Delafield’s haematoxylin in
combination with safranin gave satisfactory results.

Anatomy of healthy stem

XyLEM.—The normal wood is of the diffuse, porous type (fig. 1),
corresponding in this respect to other species of Populus. The ves-
sels are numerous, visible to the naked eye, and are slightly larger
in the spring wood than in the summer wood. They form a con-
spicuous ring of large pores within the earlier wood where it joins
with the late wood of the previous season. In most growth rings
an irregular, oblique, tangential-radial arrangement of pores can be
seen, which, however, do not cross the junction of the spring wood
and summer wood of the preceding season’s growth. The vessels
are of the bordered pitted type in the xylem of secondary growth.
In the xylem that arises from the growing point, however, a great
many vessels with spirally thickened walls are formed.

MEDULLARY RAY.—The rays of this species, as in all the species
of Populus which the writer has examined, are scarcely visible with
the ordinary hand lens. Only uniseriate rays have been found to
occur in normal wood, the cells of which are richly supplied with
simple pits (fig. 3). The ray is made up of uniform parenchyma
cells elongated horizontally. Viewed radially, a ray appears as 4
muriform structure composed of several rows of tabular cells. The
walls of the cells of the medullary ray are pitted, and the walls
therefore have a lattice-like appearance when seen in radial section.
The ray cells in most cases contain a considerable amount of starch.

In tangential section, the cross-sections of the rays are shown to
good advantage. The uniseriate character is very evident. The
rays vary from three to seventeen cells in height, and are distinctly
spindle-shaped, the end cells tapering to a decided point. The cells
between the end cells vary in shape from cubical to prismatic (fig. 3).

In the radial aspect one is best able to study the wood fibers that
compose the bulk of the xylem. These wood fibers are slender, non-
septate, spindle-shaped, sharp-pointed cells with narrow cavities.
They extend nearly parallel to one another, and diverge from their

1922] HYDE—GALL ON POPULUS 189

course only in weaving around the medullary rays. The wood fibers
are perforated with numerous, almost circular bordered pits.

In cross-section the fibers are nearly square in outline, and have
relatively thin walls. The walls are somewhat thicker in the sum-
mer wood than in the spring wood. The fibers, according to
REcorD,? have a maximum length of 1.90 mm., a minimum length
of o.50 mm., and an average length of 1.15 mm.

Bark.—The bark as herewith considered includes all that por-
tion of the stem outside the cambium layer, and is composed of
epidermis, cortex, and phloem.

The epidermis of young twigs is smooth and colorless. Beneath
this is found a layer of parenchyma, from four to seven cells thick,
encircling the stem. As the stem becomes older the outer tissues
disappear and are replaced by suberized tissue produced through
the activity of the phellogen. In the case of normal twigs this cork
tissue never becomes very thick. The fibers are thick-walled ele- »
ments, with sharp pointed, unbranched ends. They are arranged
in groups which are in turn arranged in bands that extend around
the stem, concentric with the cambium ring.

The phloem is composed of sieve tubes, companion cells, and
phloem parenchyma. In many of the cells comparatively large
spherical crystals are found.

The pith rays extend into the phloem. They are uniseriate, but
broaden considerably as they progress into the cortex. This broad-
ening is due to the fact that the cells are thickened tangentially, and
not to any increase in number of rows of cells.

Piru.—The central pith of the stem is composed of cylindrical
cells with thin walls. The pith area is about 0.8 mm. in diameter,
and varies in color from a light gray to a reddish brown. Many of
the cells contain starch and crystals. The crystals are spherical in
shape, and never more than one is found within a cell. The outline
of the pith area in cross-section is usually distinctly five-angled, but
all gradations between this and a circular outline occur.

CamBium.—The cambium of this tree is similar to that of other
dicotyledons. It consists of a layer of thin-walled, delicate, tabular

2 Recor, S. J., Economic woods of the United States. New York: Wiley and
Sons. 1919.

Igo BOTANICAL GAZETTE [OCTOBER

cells. These cells have their long axes extending vertically, and
are wider tangentially than radially.

Anatomy of gall

Gross ANATOMY.—Many galls were examined and were found to
vary considerably in size. The largest one measured was 3.5 cm.
in diameter, and the smallest one had a diameter of 0.5 cm. They
vary in shape from ovoid to globular, and usually encircle the stem.
Ordinarily the galls appear singly, but it is not unusual to find them
very close together or even confluent on the stem, and characteristi-
cally at the nodes. The outer surface of the gall is roughened much
more than the outer portion of the normal bark, either above or
below the hypertrophy. There has been such a development of
suberized tissue on the periphery of the gall, due to the presence of
the disease, that it becomes broken into deep, irregular, longitudinal
' fissures (fig. 5).

Pycnidia of Macrophoma are scattered irregularly over the sut-
face of the gall. These pycnidia are flask-shaped, and are imbedded
in the parenchymatous tissue of the gall. They have a pseudo-
parenchymatous wall and open to the exterior through an ostiolum.
The pycnidia are barely visible to the naked eye, and are more
abundant in the region of the fissures. Considerable sloughing of
the bark from the surface occurs, especially at the time of the
increased activity of the cambium region in the spring.

It is interesting to note the enormous increase of the hyper-
trophied part of the stem in comparison with the apparently normal
stem above and below the gall. No less interesting is the macro-
scopic comparison of the normal wood and bark of the region below
with the region through the gall (fig. 8). It shows to advantage the
relative amount of increase of the tissue in question, as a result of
the stimulation of the pathogene. The averages, obtained from the
measurements of twenty-five galls of various sizes, are as follows:

Radius of galls... .. a ee eee 10.5 mm.
Rachie OF wood OF Gals... i ee. 7.0
‘Thickness of bark of gallg. 0.2, 3.5
Radius of stem immediately below gall.......... 5.0
Radius of wood immediately below gall.......... 4.

1922] HYDE—GALL ON POPULUS IQI

It is apparent from these figures that the diameter of the normal
stem is composed of 10 per cent bark and go per cent wood, while
in the diseased twig 25 per cent is bark and only 75 per cent is wood.
The section through the gall has increased 110 per cent, the wood
55 per cent, and the bark 600 per cent over the same tissues in the
stem just below the gall.

Oricin.—The hypertrophy first makes its appearance on the
twig in the form of a slight swelling, at or about the time of renewed
cambial activity in the spring, which for the region of western Mon-
tana is about the first of May. This original swelling is brought
about by the increase in number and also the increase in size of the
cells of the recent phloem and xylem as secondary growth takes
place. It would appear evident, therefore, that this increase in size
and number of the cells is brought about by the stimulating effect
produced on the cambium by the presence of the fungus. To say
that this is due to enzymatic action is only a conjecture, but this is
the most plausible explanation.

In the majority of knots sectioned the distortion reached to
the pith, at least in some portion of the stem, which indicates that
infection took place in the infancy of the twig, as xylem once formed
in the region surrounding the pith ordinarily is not subsequently
distorted. This, coupled with the fact that the hypertrophy is
almost always formed where the twig branches, indicates that the
pathogene gains entrance to the host in the region of, and during
the formative period of the lateral buds.

The galls evidently arise as the result of the original infection.
Frequently when a young lateral twig becomes infected its growth
is stunted distad to the infection, and as a result numerous short
lateral twigs are present that simulate spurs. Although these spurs
may be only a few millimeters in length, they usually show several
years growth, as evidenced by the number of terminal bud scars
present. These spurs usually protrude from the branch at a dis-
tinct right angle, while the normal twig protrudes at an angle of
approximately 30° (figs. 5-7). This increased angle is brought
about mechanically, the gall forming in the axil exerting a pressure
that forces the spur downward.

XyteM.—In looking at a transverse section of diseased wood such
as is shown in fig. 2, one is impressed by the enormous broadening

1Q2 BOTANICAL GAZETTE [OCTOBER

of therays. In this view the rays are clearly seen to be multiseriate.
Occasionally the rays are seen to join together, giving rise to still
wider ones. In a great many cross-sections the rays do not take a
direct course through the xylem, but are often broken and their
course considerably interrupted. In many cases this ray paren-
chyma is scattered among the wood fiber and wood parenchyma
elements.

The vessels have become greatly distorted throughout (fig. 2).

This is due to the flattening of the tubes in a radial direction. In
most cross-sections the pores are few in number, and in sections of
some galls they are entirely absent (figs. 2, 9). Considerable
increase in wood parenchyma cells is seen in the diseased wood.
a great many cases the wood fibers are bent at right angles, the
bend always being toward the periphery. Due to the bending, a
transverse section often shows these fibers in a longitudinal view
(fig. 2). This distortion is brought about largely as a result of ©
crowding, due to the great increase in the number and size of the
cells of the medullary rays.

In fig. 4 is shown a tangential section of diseased wood through
a gall which illustrates to good advantage the characteristics of the
medullary rays, which vary from one to several cells wide tangen-
tially. This broadening is due to the increase in number, as well as
to the increase in size of the individual cells making up the rays.
That these ray cells are larger in the diseased wood than in the-
normal wood is apparent by comparison of fig. 3 and fig. 4, the
magnification in both cases being the same. It is also evident that
there is considerable increase in the size and number of the wood
fiber and wood parenchyma elements. The medullary rays some-
times become so broad that their tangential diameter equals, or is
even greater than their vertical diameter (fig. 4).

The average of one hundred measurements of the diameter of
the medullary ray cells, in the tangential sections of normal and dis-
eased wood of the same age, gave for the former 13.2 » and for the
latter 27.94. This shows an increase of slightly over 100 per cent
in these cells as a result of the diseased condition. Measurements
of the diameters of the wood fibers in the same sections gave 42
average in the normal wood of 12 u and in the diseased wood an
average of 16 yp.

1922] HYDE—GALL ON POPULUS 193

Here and there in the xylem of the diseased area uniseriate rays
occur, but these are far outnumbered by the multiseriate rays. The
ray tissue in the diseased xylem makes up approximately 30 per cent
of the wood, while it is evident, by comparing the figures, that in
the normal wood the ray tissue makes up a much smaller pro-
portion.

Bark.—The distortion of the elements of the bark of the gall are
not so pronounced asin the xylem. In the bark the principal effect
is found to be a decided increase in size and number of the cells of
the several tissues. As a result of the normal reaction of the host,
in an attempt to overcome the injurious effects of the pathogene, the
amount of suberized tissue is increased manyfold, so that now there
are as many as fifty rows of cork cells. The parenchyma cells of
the primary cortex are considerably larger and more than doubled
in number. The average of numerous counts made of the number
_of rows of parenchyma cells between the cambium and the periderm
in normal and diseased bark shows for the former 28, and for the
latter 65. The phloem rays are multiseriate, often comprising six or
seven rows of cells. These rays are sometimes bent tangentially, as
seen in cross-section.

The phloem tissue is greatly increased in the diseased twig.
This increase is largely due to the multiplication of the phloem
parenchyma cells and the subsequent growth of the cells to a size
slightly beyond the normal. Physiologically the phloem does not
appear to be greatly interfered with during the younger stages of the
gall. As the gall becomes larger, considerable pressure is exerted
upon the sieve tubes, as is indicated by the fact that they are flat-
tened radially.

The functional disturbance seems to be more closely connected
with the xylem than with the phloem, as it is here that the distortion
of elements is the greatest. This disturbance is manifested in the
gradual dying of the twig above the hypertrophy (fig. 7), which,
however, does not usually occur unless there are several knots
upon the twig. In cases where only one knot is found on the twig
there usually i is no noticeable disturbance distad to the knot.

The writer believes the death of the twig to be due to the fact
that sufficient water and minerals cannot get through the vessels of
the xylem to the leaves beyond the galls. The supply of water and

194 BOTANICAL GAZETTE [OCTOBER

minerals is shut off because the xylem elements are so twisted and
distorted that the vessels as vertical tubes and efficient water car-
riers have largely disappeared. The water and mineral nutrients
are able to pass slowly one or two galls by diffusion, even though
the vessels are greatly distorted, but when several galls are present
in the path the movement is so interfered with that growth is re-
tarded and sooner or later the tip part of the twig dies above the
knot.

Piru.—No striking effects on the central pith as a result of the
gall formation are noticeable, but in some larger galls the pith area
is somewhat compressed, and the individual pith cells in these cases
have lost their characteristic cylindrical form and have taken on an
angular appearance.

CampiumM.—The cambium appears to be very active in the
younger galls, as evidenced by the comparatively larger cells and
nuclei. As the gall grows older this activity gradually grows less,
until it is brought to an end by the death of the twig. In cases
where death of the twig distad to the gall does not occur, the activity
of the cambium eventually becomes almost negligible. The cam-
bium ring as a whole becomes greatly distorted and interrupted in
many places. The wood fibers that are bent toward the periphery
are responsible for this interruption of the cambium. The cambium
never entirely loses its identity (fig. 9). Many nascent cells are
isolated from the cambium that give rise by continual division to
isolated groups of phloem in the xylem region. These groups are
more often formed between the spring wood and the summer w'
of the preceding years’ growth. They are usually crescent-shaped,
and suggest the pith flecks often found in other woods. ‘There are
no isolated xylem groups formed in the phloem, but a great many
wedgelike xylem elements extend through the cambium into this
region (fig. 9).

Summary

1. The normal wood of Populus trichocarpa conforms closely to @
typical dicotyledonous, diffuse, porous wood.

2. In western Montana and eastern Idaho a gall disease threat-
ens to interfere with the commercial uses of this tree.

1922] HYDE—GALL ON POPULUS 195

3. Only uniseriate rays are found in the normal wood of this tree,
while in the diseased wood the rays are considerably broadened,
often being several cells wide tangentially.

4. The average increase in the diameter of the stem, due to
gall formation of several galls’measured is 110 per cent, of xylem
55 per cent, and of phloem 600 per cent.

5. The xylem elements are greatly distorted, the vessels are
flattened radially, and the wood fibers are often bent at right angles,
due to crowding as a result of the great increase in number and size
of the cells of the medullary ray.

6. In the bark the greatest effect noticeable is the increase in
size and number of the parenchyma cells.

7. The phellogen is stimulated to unusual activity, and con- —
sequently the suberized tissue is considerably increased.

8. The distortion of the vascular elements, because of the inter-
ference with the transpiration stream, often results in the twigs
dying above the galls.

g. The central pith is not greatly altered in the diseased stem.

10. The cambium is sometimes altered by distortion, but never
completely loses its identity.

11. In addition to the evidence of constant association of
Macrophoma tumefaciens with the lesions, the histological examina-
tion supports the idea that this fungus is the cause of the disease.

12. Infection experiments on pathogenicity are as yet lacking.

Acknowledgment is made to Professor W. W. RowLEE, under
whose direction this study was made, and to Professor D. Reppick
for many suggestions in the preparation of the manuscript.

CoRNELL UNIVERSITY

EXPLANATION OF PLATE VI
All photomicrographs show magnification of 85 diameters.

Fic. 1,—Transverse section of normal wood, showing one annual ring
complete.

Fic. 2.—Transverse section of diseased wood, showing distorted multi-
seriate medullary ray and radially flattened vessels.

Fic. 3.—Tangential section of normal wood, showing uniseriate medullary
rays and normal fibers.

196 BOTANICAL GAZETTE [OCTOBER

Fic. 4.—Tangential section of diseased wood, showing broadened medul-
lary rays and enlarged and distorted fibers.

Fic. 5.—Twigs bearing characteristic galls; reduced 4.

1G. 6.—Normal twig, showing method of branching; reduced 4.

Fic. 7.—Cluster of branches, showing characteristic habit of galls; many
of these twigs were dead at tips; much reduced.

Fic. 8.—Transverse section of gall on five-year old twig; to right of this
is shown transverse section of twig just below gall; reduced 3.

Fic. 9.—Characteristic irregularity of cambium ring in diseased twig.

Fic. 10.—Normal one-year old twig and twig of same age bearing gall;
reduced 4.

PLATE VI

BOTANICAL GAZETTE, LXXIV

HYDE on POPULUS GALL

POLLINATION IN ALFALFA
F. A. COFFMAN
(WITH FIVE FIGURES)

The problem of fertilization in alfalfa has been a matter of
considerable controversy for several years. Many experiments
have been performed in endeavoring to determine what factor is
most largely responsible for pollination in this plant. In the review
of investigations published by Piper, Evans, McKEEg, and Morse’
it is stated that the amount of self-pollination varies with the season,
and that its real importance in seed production is doubtful. H1prE-
BRAND? is cited as having believed as early as 1866 that fertilization
may take place in untripped flowers, and URBAN? (1873) is referred
to as thinking that in some cases untripped flowers form pods.
Most of the work of recent investigators has consisted of attempts
to determine the most important agents in tripping the alfalfa
blossom. Although a considerable number of experiments have
been carried on, no definite conclusions seem to have been reached.
Roserts‘ found anthers dehiscing and stigmas pollinated in the
early bud stages of the alfalfa.

An investigation which was begun by the writer during the latter
part of September 1916, and which was continued until killing frosts
in October, had for its object the determination of the stage at
which the stamens of the majority of alfalfa flowers really shed
their pollen. It was found that light frosts do not seem to have
any effect upon pollination, the percentage of pollinated to unpol-
linated flowers not being affected so far as could be noticed in
any of the classes of buds examined.

Prrer, C. V., Evans, M. W., McKee, R., and Morsg, W. J., Alfalfa seed pro-
duction; vitlication studies. Bull. 75. U.S. Dept. Agric. 1914.

2 HitpeBranp, F., Uber die Vorrichtungen an einigen Bluthen zur Befruchtung
durch Insektenhulfe. Bot. Zeit. 24:75. 1866.

3 URBAN, I., Prodromus einer Monographie der Gattung Medicago. Verhandl.
Bot. Ver. Provinz Brandenburg 15:13. 1873.

4Roserts, H. F., Alfalfa varieties, breeding, seed, and inoculation. Quarterly
Rept. Kans. State Board Agric. 35:180. 1916.

197] [Botanical Gazette, vol. 74

198 BOTANICAL GAZETTE [OCTOBER

The flowers were divided arbitrarily into four classes, according
to the stages of their development, as follows: straight bud, fig. 1;
pointed bud, fig. 2; hooded bud, fig. 3; and erect standard, fig. 4.
The lengths of the flower in millimeters were determined before
they were examined, and these measurements serve to some extent
as checks on their stages of development. In the fourth class of
blossoms, the flowers did not measure longer than in the hooded bud

Fic. 1.—Alfalfa bud representing “straight bud” stage; corolla in this stage has
not grown out much beyond calyx; only standard petal can be seen; it is folded around
all of the others.

Fic. 2.—Alfalfa bud representing “pointed bud” stage; standard petal is seen to
be distinctly curving upward in its growth; lower edges of wing petals, which together
fold down over keel, are visible.

stage. This is because all measurements were taken from the base
of the calyx to the tip of the flower in the first stages. After the
standard began to arise, the measurements continued to be taken
to the tip of the interlocking envelope of the wings and keel, which
did not further elongate after the erection of the standard. After
being measured, each flower was dissected by means of needles and
forceps at a magnification of 23 diameters, under a Zeiss binocular
microscope, using F-55 objectives and no. 5 oculars. The dissec-

1922] COFFMAN—POLLINATION IN ALFALFA 199

tions were made by removing first the standard, and then one of
the wing petals, thus exposing the interior of the flower to view.
Care was taken not to set off the tripping mechanism, nor to disturb

Fic. 3.—Young alfalfa flower called “hooded bud” stage; standard petal has
risen Sealy to full height, and is beginning to spread; wing petals distinctly seen
protruding, folded over keel, which is not yet visible.

—Alfalfa flower fully open and ready for tripping, representing ‘erect
dae > aes standard fully risen and spread; wing petals are separating, showing
keel within.

the stamens or otherwise injure the flowers. Flowers believed to
have been injured in the dissecting process were discarded and not
recorded

200 BOTANICAL GAZETTE [OCTOBER

The ratio of buds with anthers dehisced to those with anthers
intact, in the pointed bud stage, was surprisingly close. Probably
twenty flowers of the straight bud stage, in which the anthers had
dehisced, were discarded, since it was thought that they might have

TABLE I
Flower length (mm.) | “intact” | dchiseed | pollinated
Straight bud stage
ry ee he Ts 20 I I
Oe ea eee re 49 I I
FO ee aa ets eee 12 I I
Se eee ae a es I I
TOs sss 81 4 4
Pointed bud stage
One yen ey 18 I I
1: ESR Ey RTS 44 22 19
Se eee ee at 4I 37
ON Gee ee 3 19 19
YOR Cede ee ee eee Pe ea ek I I
ROM es 86 84 77
Hooded bud stage
Tee ar eee het ie cae I I
Diva eS 8 8
Ciera: 2 18 18
IO gees es I 9
AO 3 36 36
Erect standard stage
Fi cccoupevirerie ss ee: I I
OE ay ger WORE at ed Eat 2 2
ere ra reir ou ree 13 13
AD iae Cis Cle es Cece ys ys poet 4 4
ce Pare ge ce eee he ey Parres Ene I I
Bee ee i a I I
TOM ee 22 22

been injured by dissection, thereby causing the bursting of the
anthers. In handling the flowers of the hooded and erect standard
stages, care was exercised to prevent them from tripping. The
standard was first removed so as to keep the anthers from striking

tees COFFMAN—POLLINATION IN ALFALFA 201

it and from being broken, should the flower accidentally be tripped.
One of the wing petals was then pulled away and the stamens
examined. Most of the flowers in the erect standard stage, as they
were found in the field, had already been tripped, untripped flowers
being rather difficult to secure. A total of 316 flowers was examined
and recorded as follows:

Straight bud stage....... 85 Hooded bud stage....... 39

Pointed bud stage....... 170 ~—— Erect standard stage... .. 22

In the straight bud class, the flowers measure 5—8 mm. in length,
and of the total number recorded, in only four instances had the
stamens shed their pollen. The flowers in the pointed bud stage
are considerably longer, being 6-10 mm. in length, and practically
one-half of those recorded were pollinated. The hooded and erect
classes of buds do not differ greatly from each other in size, varying
from 7 to 12mm. in length. But three flowers in the hooded bud
stage had not been pollinated, while no unpollinated erect standard
blossoms were found. The data as taken in this investigation, on
the stages of bud development in relation to pollination, are given
in table I.

From the data secured, the percentages of pollination of the
flowers of different lengths, regardless of their stages of develop-
ment, are given in table II.

TABLE II

Pepe | No ecumined [YO *ERCS | autiaesiintoct | Gehieced janthors Cohiaces
eee ee! 21 20 95-24 I 4.76
a eae es 69 67 Q7-11 2 89
OE Soe 8r 56 69.14 25 30.86
See eae 73 21 28.77 52 71.23
ye ene 55 5 9.09 50 90.91
Mes ear. 15 I 6.67 14 93-33
Mii, I ° ° I 100.00
3 eh eet I ° ° I 100.00

Total 316 8 as TE RE Baan

According to table II, anthers do not seem to shed their pollen
before the flowers have reached 7 mm. in length, and most of them
have done so by the time they are between 9 and 10 mm. long.

202 BOTANICAL GAZETTE [OCTOBER

Percentage of individuals with anthers dehisced.

100
Graph
90 plotted to
nearest
integers,
80 showing
percentage
of flowers
70 with an-
thers
dehisced.
60 Abscissa
denote
classes of
50 flowers
examined,
m lengths
40 by mith-
here
Or dinates
50 _ denote per-
centage of
individuals
20 in each
class.
10

Pe ee
Classes of flower lengths by millimeters.

Fic, 5

1922] COFFMAN—POLLINATION IN ALFALFA 203

This relation between dehisced anthers and flower length is shown
graphically in fig. 5.

From the data secured as the result of this preliminary investiga-
tion, it appears that practically all alfalfa blossoms shed their
pollen during the pointed bud stage, and before the hooded bud
stage is reached. Judging by this, it would seem that tripping is
not essential to pollination.

The alfalfa flower apparently begins to shed its pollen while
yet comparatively small, being only about 7 mm. in length, which
in hybridization operations would necessitate emasculation being
accomplished while the blossom is still in the straight bud stage,
in order to eliminate all possible danger of self-fertilization. As a
matter of fact, this is a practical impossibility from the mechanical
standpoint in the field at least, the flowers being emasculated in
alfalfa crossing work by tripping them not earlier than the hooded
bud stage and generally later, the pollen then being washed out
with an atomizer spray. It is impossible to emasculate the flowers
earlier than the hooded bud stage. The writer believes, however,
that there is great danger of pollination of the stigma and of con-
sequent self-fertilization, before the time when the flowers are
ordinarily tripped in alfalfa by hybridizing operations.

This investigation was carried on in connection with graduate
work under the direction of Professor H. F. RoBerts, of the Depart-
ment of Botany, Kansas State Agricultural College. The illustra-
tions are from pp. 202-203 of his paper referred to herein.

U.S. DEPARTMENT OF AGRICULTURE
Axron, CoLo.

PROTECTIVE POWER AGAINST SALT INJURY OF
LARGE ROOT SYSTEMS OF WHEAT
SEEDLINGS
W. F. GERICKE

That wheat plants can be made to grow very large root systems as
compared with the growth of their tops by certain properties of nutri-
ent solutions, has been shown in a previous paper." T he writer has
also shown that under certain conditions large root systems of wheat
seedlings 4-6 weeks old play an important réle in the number of
tillers? the plant may produce. These observations suggested fur-
ther experimentation where differences in the extent of the root
systems of the plants would enter as the variable factor. It seemed
plausible to expect that the relative physiological values or growth
efficiencies of different nutrient solutions, and the tolerance of plants
to salts, were not inconsiderably affected by the extent of the root
development of the test plants when placed in the media. The
present paper bears upon an investigation on these points.

Three different kinds of nutrient solutions were selected for the
tests. These were solutions whose relative values as growth media ~
had previously been obtained. The composition, molecular concen-
tration of the salts, and the relative physiological values of these
solutions stated as ‘‘good,” “medium,” or ‘‘poor” were as’ follows:

Solution no. 1.—o.0102 mol. KH.PO,; 0.0057 mol. Ca(NO;)2;
0.0062 mol. MgSO,. Good.

Solution no. 2.—o.014 mol. K,SO,; 0.002 mol. Ca(NO,),; 0.002
mol. Mg(H.PO,).. Very poor.

Solution no. 3.—o.016 mol. MgSO,; 0.002 mol. Ca(NO,)2; 0.002
mol. KH,PO,. Poor if air temperature and transpiration for growth
were high; medium if air temperature and transpiration for growth
were relatively low.

* GeRICKE, W. F., Root development of wheat seedlings. Bor, Gaz. 72:404-406.
1921.

, Certain relations between root development and tillering in wheat. (To
appear in Amer. Jour. Bot. 9:1922

Botanical Gazette, vol. 74] [204

1922] GERICKE—ROOT SYSTEMS 205

Sets of eight containers (Mason jars) of one-half gallon capacity
were used for each of the different solutions and for each of the
two different classes of wheat seedlings. These classes of seedlings
were distinguished by a difference in the extent of root growth
from that of top growth which the plants had when placed in
the nutrient solutions. The method employed to obtain seed-
lings with large root systems was that referred to in the earlier
paper. This consisted in allowing the cultures to grow in one
quart Mason jars filled with tap water for five weeks before the cul-
tures were placed in the nutrient solutions to be tested. The plants
at this time had a root mass 70-80 cm. long, and had about one-half
of their total dry matter in the roots. They were transferred from
the tap water directly to the three nutrient solutions to be tested.
To grow contemporaneously with these, other seedlings (young
plants just germinated and therefore having small root systems)
were set out in other sets of containers filled with the nutrient solu-
tions to be tested. The seedlings in this latter case were 6-8 cm.
high, with roots 8-10 cm. long, about 20 per cent of the dry weight
of the plant thus being roots. Subsequent treatment of all cultures
was alike, and this included additions of a small amount of FeSO,
to each culture at regular intervals, also regular additions of distilled
water to make up the loss of water by transpiration. The test
period was six weeks. The experiment was carried on in the green-
house during parts of July and August, the range of temperature
being 20°-32°C. The relative humidity of the greenhouse did not
permit excessive transpiration. At the end of the test period, the
plants were harvested, dried, and weighed. Table I gives the data

obtained.

In taking up the data in detail, it may be noted that the cultures
which had large and extensive roots (class A), when placed in the
“good” nutrient solution no. 1, produced less than one-half as much
total dry matter as did the cultures which were started with com-
paratively small roots (class B). The latter class of cultures at
the end of the test period had the largest root growth, exceeding by
more than 76 per cent that of the next largest. The cultures of class
B are to be considered as normal plants when set out, the other
class not. Even though class A had by far the larger roots when the
test was started, it is obvious that these large roots did not operate

206 BOTANICAL GAZETTE [OcTOBER

as a means to secure as great a rate of growth for the plants, espe-
cially for the aerial portion, as was obtained by the plants started
with relatively small roots having less surface exposed for absorption

TABLE I

EFFECT ON DRY MATTER PRODUCTION OF DIFFERENT ROOT SYSTEMS OF WHEAT
SEEDLINGS GROWN IN DIFFERENT NUTRIENT SOLUTIONS (WEIGHT IN GM.)

Crass A ss B
Cultures having large root systems when placed in Cultures having small root systems when
solution placed in solution
Tops | Roots | Total ‘Tops | Roots Total
SOLUTION I
1.22 0.42 1.64 3.00 °.73 3-73
1.13 0.37 1.50 3.29 1.09 4.38
1.35 0.40 575 2.60 0.53 3-13
1.06 0.38 1.44 3.12 0.95 4.07
1.38 0.48 1.86 2.95 0.70 3-65
1.07 0.35 1.42 3.04 0.67 3-71
1.41 0.55 1.96 3.02 0.62 3.64
irs °.40 YUSs 2.07 o.60 3-57
AVEPage......5 5: 1.26 0.42 1.64 3.00 0.74 3-74
SOLUTION 2
1.65 0.43 2.08 0.62 0.12 -84
1.42 0.35 197 °.60 0.10 90.79
I.00 0.36 1.36 0.45 0.10 0.55
I 0.37 1.86 o.61 0.12 0.73
1.38 0.36 1.74 0.75 0.11 .86
1.10 0.39 1.49 G.55 ° 0.64
1.32 0.37 1.69 0.53 0.10 0.63
1.10 0.39 1.49
AVEIape: .o 5.5. 1.30 0.38 1.68 0.59 0.11 0.70
SOLUTION 3
I 0.39 1.39 2.94 0.35 3-329
0.98 0.35 =. 43 2.96 0.35 3-31
1.24 0.42 1.66 3.00 0.46 3.46
1.61 0.48 2.09 2.40 0.27 2.67
1.00 0.33 5B 2.97 0.42 3-39
1.07 0.30 1.87 *1.62 0.21 1.83
1.05 0.30 1.35 2.50 0.32 2.82
£75 0.37 2.12 2.74 °.39 3-13
Average. 2... 5.5 ¥.21 0.37 1.58 2.64 0.35 2.99
* Two plants in this culture died.

processes. On the other hand, it is not evident that the large root
systems prevented the cultures of class A from attaining to the

1922] GERICKE—ROOT SYSTEMS 207

measure of growth obtained by the cultures of class B. That the
cultures of class A failed to give the measure of growth obtained by
the cultures of class B must undoubtedly be attributed to some
effects of the previous treatment, and of which the large roots in
this case apparently may be considered but an incident. In this
connection it can be argued that the cultures of class A were stunted
and did not possess the same potential power or capacity for growth
as did those of class B, and therefore regardless of any possible bene-
ficial effect, if these large roots meant a greater surface for absorp-
tion, this could not compensate to overcome the stunted effects suf-
fered by the plants. Undoubtedly the capacity of a plant to grow
is affected by the rate of absorption of nutrients, and vice versa,
the rate of absorption of nutrients is affected by the growth of the
plants, so that the absorbing capacity of any comparable unit area
of root surface must vary with conditions. It appears, therefore,
that the data of the cultures grown in solution no. 1, taken by
themselves, do not give any indication as to what effects the differ-
ent root systems had in the results.

The results obtained from solution no. 2 are decidedly different.
The seedlings having large roots, when placed in this ‘‘very poor
nutrient solution, produced about two and one-half times as much
dry matter as did the other class of seedlings grown in this solution.
The yield of the cultures of class A grown in solution no. 2 were
approximately of the same magnitude as those grown in solution
no. 1. The yield of the cultures of class B having comparatively
small roots when placed in solution no. 1 was about five and one-half
times larger than that of the corresponding cultures grown in solu-
tion no. 2. The explanation for the differences in growth obtained
from the two classes of seedlings grown in solution no. 2 seems to be
due to differences in the extent of the root systems these cultures had
when placed in the media. It is quite obvious that the great differ-
ence in total dry weight obtained from the two classes of cultures
grown in solution no. 2 is due to the very small growth made by
the cultures with small roots, and not to any exceptionally good
growth made by the cultures with large roots. The effect of solu-
tion no. 2 upon the one class of seedlings (class B) was to prevent
its making such a measure of root growth as could be necessary to
enable the plants to make even a moderate measure of top growth.

208 BOTANICAL GAZETTE [OCTOBER

The injury to these seedlings was relatively great, therefore, but
this was not the case with seedlings having large root growth

It appears that there are several reasons that can be offered as an
explanation for this relatively good growth obtained from the cul-
tures with large roots grown in solution no. 2. The roots of these
cultures, presumably because of their age, had much suberized
tissue. This could inhibit the entry of excessive amounts of salts.
It could also cause the precipitation of some of the salts in the
root mass without doing injury to the plants, and, also in a
selective way prevent or retard the absorption of toxic ions. On
the other hand, this large root system was beneficial to the plant
growth in this poor solution, in that it still permitted sufficient
absorption of the essentialions. The greater surface exposed to ab-
sorption of nutrients, therefore, could compensate for the decrease in
the rate of intake of essential nutrients per unit area of root surface.

Results obtained from solution no. 3 show that the plants having
comparatively small root systems, when placed in the solution, pro-
duced approximately 90 per cent more dry weight than did the
other class of cultures grown in this same kind of solution. The
dry weight of the cultures of class B was also more than four times
larger than that of the corresponding cultures of solution no. 2.
The growth obtained from class B cultures in this solution (no. 3);
in which MgSO, composed eight-tenths of the total salt concentra-
tion, must be considered as very good. Had growth conditions pre-
vailed that would have induced a higher rate of transpiration, these
cultures would not have attained to the value they held in this test.
It is to be noted that these cultures had the lowest percentage of
dry matter in the roots of all sets, being 11.7 per cent of the total
growth obtained, and constituting a very low value for wheat plants
six weeks old. One effect of this solution was to retard root growth
in the cultures of class B as compared with the growth of top.
Under conditions of excessive transpiration this condition would
have acted harmfully to the plants. As it was, the cultures of class
B having the smallest root systems as compared with the tops of the
plants appeared to have been the most efficient, if ratio of root
growth to top be taken as the criterion.

The dry weight of all the cultures having large root systems
(class A) when placed in the three different kinds of solutions were

1922] GERICKE—ROOT SYSTEMS 209

of approximately equal value, having increased approximately five
times in weight during the six weeks’ period of growth. This test
shows that these three solutions, markedly different in composition,
must be considered as of equal value as media for the growth of
wheat seedlings five weeks old having large root systems, when
placed in the solutions and grown for six weeks. These same solu-
tions, however, must also be considered markedly different physio-
logically, when the test plants are wheat seedlings 6-8 cm. high
with small roots 8-10 cm. long.

All the cultures with large roots may be considered as having
been injured by the treatment of the first five weeks’ growth in
tap water, because they fell short in attaining the maximum
growth rate obtained by the cultures with small roots (class B) in
solution no. 1. Whether any treatment that can induce large root
growth of a wheat plant, either at the expense of top growth or not,
can subsequently be made to operate as a means to secure a greater
growth rate for the plant as a whole, because of a greater root sur-
face exposed for absorption, needs further investigation. It is
probable that in the present experiment the treatment to obtain -
large roots was too severe, and that exposure for a less time to the con-
ditions by which large roots were obtained would have given a larger
measure of growth when set into these solutions than was obtained.

The extent of the root system appears as an important factor
that affects the magnitude of growth obtainable from a given nutrient
solution. It is conceivable, therefore, that extent of the root systems
of plants plays an important réle when plants are grown in the field.
That some plants are more resistant than others to certain untoward
conditions, such as excessive amounts of salts in alkali regions, may
not be due to any peculiar genetic factor of the plant, but simply be
the response from differences in root development occasioned by
certain conditions in the environment in the field. The common
Observance in the field of a greater tolerance for salts of older
plants than young ones apparently can well be accounted for in
their root systems. This, however, does not mean that differences
in extent of root systems any given kind of plant may have are due
only to causes operative in the external environment. Differences
in root systems may also be due to genetic factors.

AGRICULTURAL EXPERIMENT STATION
UNIVERSITY OF CALIFORNIA

A NEW FRUIT ROT OF TOMATOES’
R. FrRanK POOLE
(WITH PLATE VII)

During the summer of 1921 a fungus growth following cracking
of the fruit was noted on tomatoes in several localities of Burlington
and other counties in New Jersey (fig. 1). The cracking was obvious
on both green and ripe fruit of the Stone, Baltimore, and Bonny Best
varieties, but was especially prominent and severe on the latter.
The cracking is apparently due to one or more physiological causes.
An examination showed a very dense fluffy growth of Oidiwm lactis
Fres. in the open cracks of ripe fruit lying on the ground and those
hanging on the plant to a height of several inches above the soil.
This fungus, under field conditions, penetrated the interior of the
tomato, and reduced the fruit to a soft rotten mass in from two to
five days. The disease was very common throughout the tomato
ripening period in the fields under observation. No infection was
noted on uninjured ripe fruit, cracked green fruit, or other parts of
the plant.

CausE.—The rot is due to Oidiwm or Oospora lactis. The fun-
gus is repeatedly isolated from infected tomatoes. It causes
rapid decay of ripe fruit at 20° C. ina moist chamber. The mold
is grayish white, fluffy, and dense (fig. 2). The mycelial growth is
more important than spore production. If, however, a diseased
tomato be broken open and spread out in a moist chamber for
twenty-four hours at 20° C. (fig. 3), the fungus appears very similar
in growth to the Saccharomyces. In this form the spore production
is abundant, while the mycelial growth is subdued. These two
factors of mycelium and spore production may be considered as dis-
tinguishable characteristics of this fungus from other fruit rot
organisms. The fungus grows abundantly on a large variety of
culture media. Its only known method of reproduction is non-

« Paper no. 60 of the Journal Series, New Jersey Agricultural Experiment Stations,
Department of Plant Pathology.

Botanical Gazette, vol. 74] [210

1922] POOLE—FRUIT ROT 211

sexual, typically by means of conidial spore chains. The spores
are hyaline, round or oval, and smooth. They vary in size from 2
to 6 4X6 to 4o pu (fig. 5).

Symptoms.—The fungus causes a typical soft rot of injured, ripe
tomato fruits. In some cases there is a fermentation action, due to
the fungus, which causes the cracks to widen and the juice to flow
out (fig. 2). The inner tissue is destroyed, while the peeling is not
noticeably attacked, but dries out and remains on the field as a dry,
hard shell. In advanced decay the symptoms are not easily dis-
tinguished from those of a bacterial soft rot of ripe tomato fruit.
The odor is at first agreeable, but becomes very offensive before
decay i is complete. Decay of cracked green fruit was not observed
in the field, but the fungus caused slow decay (fig. 4) in fruit that
had begun to ripen.

INOcULATIONS.—Ripe, semiripe, and green tomatoes were
placed in running water for an hour, treated fifteen minutes with
bichloride of mercury, washed with sterilized water, and placed in
dry sterilized glass chambers prepared for inoculation. No infec-
tion was obtained by spraying spores on uninjured fruit. The
fungus caused rapid decay of sliced ripe tomatoes in four to six days
at room temperature, 18—20° C. (fig. 4a). It grows very slowly on
green or semiripe fruit (fig. 40).

Spores of Oidium or Oospora lactis were introduced into the
solid ripe tomatoes by means of a platinum needle. In forty-eight
hours at room temperature there was good growth in all places
where inoculated (fig. 2b). The growth was abundant for a similar
period on deep slices made in the tomato (fig. 2a). Ripe tomatoes
which were punctured but not inoculated did not become infected
in the same chambers where other tomatoes were inoculated (fig. 2c).

DISTRIBUTION, PREVALENCE, Loss.—While no definite data are
available to show accurately the distribution of the fungus, THom’
States: ‘The mold variously known as Oidium or Oospora lactis
is another cosmopolitan organism. The same or almost indis-
tinguishable forms are found upon decaying vegetables and fruits,
which may give reason for the statement that the odor produced of

?THom, Cuas., Fungi on cheese ripening Camembert and Roquefort. Bur.
Animal Ind. Bull. 82. 1-40. figs. 3. 1906.

212 BOTANICAL GAZETTE [OCTOBER

Oidium is that of rotten cabbage.” There is considerable literature,
too extensive to mention here, dealing with Oidiwm lactis in milk
products, particularly the relation of the mold to the flavor of
Camembert cheese. Very little of this literature deals with the
fungus in relation to plant products. Prrotri and CRISTOFALETTI,’
however, have briefly reported the fungus as a parasite appearing —
in spots on tomatoes in Italy. They suggested that the fungus be
called Oidium lactis solani.

The largest losses were noted near Aiatumiows. Burlington
County. The disease was prevalent in other localities, and losses
were more or less regular over the entire tomato growing area in
localities where the disease was observed. While the loss was not
serious at any one period, there was a rather high loss for the season.

TABLE I
BonNY BEST TOMATOES

AUGUST 12 SEPTEMBER 7

Y, GPO ee 171 a1 12.2 140 25 17.8
9) CROC a nee 95 17 Ve Big 6. 13 20.3
By WAS O i ae os 102 12 1% 120 21 17-5

Coe ns es 120 19 15.8 65 17 26.1

Data were collected in tomato fields of the so-called second
early Bonny Best tomatoes, August 12 and September 7, an
from a late crop of Baltimores, September 19. This was during
the maximum ripening period of each crop. The data were
obtained by counting the total large fruits on ten average plants
and also the number that were diseased. It will be noted in table I
that the disease was slightly higher on September 7 in the Bonny
Best tomatoes than it was on August 12. It is very probable that
the conditions favoring infection were more prevalent September 7
than August 12.

The percentages of disease in table II were taken from four
series of 4~7 applications inclusive of four liquid spray and dust

3 Perotti, R., and Cristororetti, U., A fruit spot of tomato. Staz. Sper-
Agric. Ital. 47:169-216. pls. 3. figs. 9. 1914.

1922] POOLE—FRUIT ROT 213

treatments. It appears from the data given in this table that the
disease was checked with wet Bordeaux and dust treatments. Such
an interpretation is no doubt correct, but the difference of control
on treated and untreated plots is not entirely due to treatments.
There were slightly more diseased tomatoes on the untreated plots
than were formed on the treated plots. The total yield was less
on the untreated plots, because much of the fruit had prematurely
ripened and was picked or had fallen. The calculation of the per-
centages of the disease on the untreated plots with a smaller total
of fruit on the ten check plants than was obtained from ten plants

TABLE II
SERIES I SERIES 2 SERIES 3 SERIES 4
2 ; 2 2
n 1 Beg 2 a Re} : on 2 : Ong
WET SPRAY AND 38 Ses 3% gS. LE 423 33 gee
DUST TREATMENTS aa |easel sa |Ssy¥eol ga 2880 Sa |2B8o
=] a2 4 g 5 53 =| raf £ a.
B2 jeged| 62 [S82] 88 |seee) G8 [zed
= ao. ee)
38 5° au 38 aes 38 zs Ee g8 hh a0
Re A ONOCk i ce 166 4.2 rio |-3¥;8 r23 | 1075 130 2.3
2. 3-0-3-50 192 1.5 142 2.8 116 9.0 168 2.4
SAA $0. 6 211 2.9 124 0.8 193 2.0 184 3.2
4. Dest 211 iG 128 t.5 193 2.0 236 .88
5. 4-3-13-50. 193 is 140 0.7 134 4.5 211 95
OG, Cheek ss. 154 3.6 90 8.8 159 6.3 180 3:3
7+ 4-0-3-50. 157 a5 83 4.8 164 3.6 140 2.8
8. 4-4-50...... 142 I.4 126 2.4 209 ° 175 1.7
On NE es, 169 1.3 138 +5 154 » 185 2.1
TO, pick ans 146 0.7 129 0.8 198 9.6 200 o.5

on the treated plots, therefore, has resulted in a slightly increased
percentage of disease in the check over the true percentage of con-
trol. It will be noted in table II, however, that there is also a dif-
ference of control in the four treatments, which indicates that some
slight true control was obtain

he treatments were clauned i in connection with the investiga-
tion of Septoria lycopersici control. The third number in the wet
Bordeaux spray represents fish oil soap. The dust was composed
of 16 pounds anhydrous copper sulphate, 6 pounds lead arsenate,
and 78 pounds of hydrated lime. The wet treatments were applied
with a 3-row, 3-nozzle traction spray machine, while the dusts were
applied with a hand duster.

214 ECTANICAL GAZETTE [OCTOBER

Summary

1. A cracking of green and ripe fruit of Bonny Best, Baltimore,
and Stone tomatoes in Burlington and other counties of New Jersey,
due to one or more physiological causes, was observed to be severe
in 1921.

2. Oidium or Oosbora lactis was isolated from infected tomatoes.
Inoculations of ripe fruit with this fungus were positive.

3. Oidium or Oospora lactis is a widely distributed fungus. It is
known to appear in milk products, cheeses, decaying vegetables,
and fruits. On tomato fruit the fungus mycelium is dense, grayish
white, and prominent, while in other cases spores are very promi-
nently produced.

4. The treatments with wet Bordeaux sprays and dusts gave
slight control of the disease.

Appreciation is expressed for the helpful suggestions offered by
Dr. Met. T. Cook, and for the identification of the organism by
Miss ANNA E. JENKuNS, Office Pathological Collections, Washing-
ton, D.C.

AGRICULTURAL EXPERIMENT STATION
New Brunswick, N.J.

EXPLANATION OF PLATE VII
1G. 1.—Cracked ripe and green Bonny Best tomatoes, showing various
forms of cracking.

G. 2.—Ripe tomatoes inoculated with Oidium lactis (after 48 hours’
growth in partially dry chamber, 18°-20° C.): a, in fresh slices; b, punctures;
¢, no inoculation but punctured.

Fic. 3 «Diseased ripe tomatoes spread open in moist chamber for 24
hours at 20° C.; white fungus prominent on open material.

FIc. 4. =Siiced ripe and green tomatoes inoculated with Oidium lactis
(from 4 to 6 days’ growth 18°-20° C. in partially dry chambers): a, on sliced
ripe fruit; 6, on green to half ripe fruit; ¢, no inoculation on sliced ripe tomato.

Fic. 5.—Oidium or Oospora lactis: a and d, mycelial branches and spores;
b, spores of various sizes in chains; c, spores; e, spores in budding-like forma-
tion.

BOTANICAL GAZETTE, LXXIV PLATE VII

POOLE on FRUIT ROT

EFFECT OF SEEDS UPON HYDROGEN-ION
CONCENTRATION OF SOLUTIONS:
W. RuUDOLFS 3

In the course of a study on the effect of single salt solutions with
definite osmotic concentration values upon absorption by seeds’,
it was found that the H-ion concentrations of the solutions in which
the seeds were immersed changed markedly during the process of
imbibition. The general interest and importance of this phenom-
enon in connection with seed studies made its further investigation
highly desirable. Accordingly single salt solutions of magnesium
sulphate, sodium nitrate, calcium nitrate, sodium chloride, potas-
sium chloride, and potassium carbonate were prepared, ranging
in osmotic concentration values from 0.001 of an atmosphere to
7-0 atmospheres. The seeds used in connection with these solutions
were corn, spring wheat, white lupine, watermelon, Canada field
peas, Japanese buckwheat, dwarf Essex rape, and alfalfa. Fifty
seeds of each of the larger kind and 100 each of alfalfa and rape were
placed in small bottles each containing roo cc. of solution. The
bottles were placed on a laboratory table, and the seeds were allowed
to soak for a period of fifteen hours, after which the solutions were
poured off and the H-ion concentrations determined by the colori-
metric method, using the double tube standards of GILLESPIE’ and
the apparatus devised by VAN ALSTINE.!

The results of these determinations are given in tables I and II
in terms of P, values. The initial P, values of the solutions are
here compared with the final values determined at the end of

* Paper no. 83 of the Journal Series, New Jersey Agricultural Experiment Station,
Department of Plant Physiology.

?Rupotrs, W., Effect of salt solutions having definite osmotic concentration
values upon absorption by seeds. Soil Science 11: 277-293. 1921.

’Grttespre, L. J., Colorimetric determination of od ata concentration
age: buffer mixtures, with especial reference to soils. Soil nce 9: 115-136. 1920

AN Atsting, E., The determination of hydrogen-ion concentration by the
esas method and an apparatus for rapid and accurate work. Soil Science
10: 467-478. 1920.

215] [Botanical Gazette, vol. 74

BOTANICAL GAZETTE [OCTOBER

216

TABLE I
INITIAL AND FINAL Pg VALUES OF SINGLE SALT SOLUTIONS IN WHICH SEEDS

WERE SOAKED FOR FIFTEEN HOURS

3 o;onn aa Xn] Ao | Sl eeue ° m~aAD | 2} a a | 2 | ana
3 Ko) mwMNAwMnw wml wMmMmmn X=) wWmMmWMOo K2) wwM Ww wn] NNN wMwH nl wmMwnwH
8 o| ann aa al nona ae ee | al Hm Al HO ann alanw
Pe} Ne) tTrMMHy Wl MmwmMmMmM Oo muntwn wn} Mut wml MmMunMmnNnwy mi wmuMnwy
Hi Oo tr H AD Oo mond a IND MO HOF fe) 00 Qo + Ao re
fe) oO tTtMHMwy in| nNMwM Ke) muted ‘Oo wtt © NW NNW C2) wnmwnw
i - aro mo fe om isin Ye maaan a ~ AD ~ moO AMO * nina
° © Mt +tNW c= mmm st ‘Oo +t+1n t+ + © tt ‘© tTwNNNNWH eho”
1n rr Ao ard - mMm In < ROO N Nn MAD _ Om AMO vr nm Ww
é ° © ott tw X= nnn s OFM t+tt++ Ke tt Ke town ww» woh
2 A PS N AaAnondt Py Q nm Oe 3 wm HANS 5 se) aon ce is N mo mS & - maw
S Ql w« om tin tin 4 Re wmMminst |Z] Cc t+t++ |S] 0 tinm 10] «© tinMMM | O oan
g as Ssilom] GHOOAM |Z] MO] hw 8 as HAMH [Zi] mM] ae Oo ]™| a HNN Nt LM 4 mon
= v= om tin ti Ke nnw st Ko ttt © tm t+ © tiNnNINwH oO Ao
oe) AAWdAaAN + m~nNWM ~ HOM t+ HOM or) RRO OM “~ sod ise
”
‘o mOtmo tH Ko nnw + ec tot +t x2 +tTwNM © tN wH m*
+ aAaodwo sa +t) ONMN.F ~ NO Ae wt HR OO t+ Hm RO OM + me +
23 ol manntyn ol Mund ol] tHe ol tH. ol tmnwnn $e oa
t+ ooowu sn wy moO WH [=e NO A t+ HR + HmROO ay et Te
w
k= THT WwH © mmMw st k= twmnw t+ x= twit ‘Oo THM wNHWH mM.
es 4 x OOMW A wn minw & Oo NINN wn Ne OA + H MN MEO ee Sides.
Ke tHoMastw SS wWnwM Ke tw» + .= tines cc TSNINwWM) ~
in HOO AO A [ve ~~ nw fe NNN A ie eH OF wn H AMO & * Ww
. +] ntt
.o tort tH ‘o www t+ ml! touwndt o tt + © tTHNMMNwH Led
oe eee Aaa OCS : eas eo. Se pee
ee es ee ae Pela ra.
: ih <8 =e pe :9 3 & 2. ‘eauc pe Bee.
: v » om & ° , c) * M Poy
g) : sigs g Bs § Pees coc: Beees CBSE
= ‘ o ‘ .
g SBEea Baad : OnAE : OB : OF WAR : 40a
rs] : H+ SSF oe M nes ; ee i eS ; ed
ee : os fe. a
: 8 3 a8 oe 8 2s
; = I ‘ . ‘ > Ss
iy wn : w ; ite) : w : Ww . wn
ic ‘ 3 a | a | ‘. | i | .
+e) *. . a7 . *
3 5 s a - 2 £ 8 : &
5 a 4 a 232 a: « c < 5

* + =higher than 9.8.

1922] RUDOLFS—SEEDS 217

definite time intervals, during which the seeds remained in contact
with the solutions. Each of the data given represents the average
of the results obtained from two or more trials made with the same
number of seeds soaked in equal amounts of solution for time
periods of the same duration.

From the data of table I it will be observed that in all cases the
- H-ion concentrations of the solutions were markedly increased by
contact with the seeds, even when strongly alkaline solutions of
potassium carbonate were used. ‘The seeds immersed in solutions
of different concentrations of a single salt had a tendency to bring
the P, values of the solutions to a point which was fairly constant
for a given species of seed, regardless of the original salt concentra-
tion or of the initial P, values of the solutions, except when the
- solutions .were very dilute. The maximum reaction change pro-
duced by corn in the various concentrations of all the salts used,
except potassium carbonate, brought the final P, values of the
solutions to approximately 4.1, varying only slightly above or below
this value except in the very dilute solutions (0.01 and 0.001 atm.)
as previously noted. While the final P, values produced by the
seeds of other species were approximately constant in the different
concentrations of the same salt, they varied considerably in the
solutions of the different salts. For example, the final P, values
produced by wheat in the magnesium sulphate solutions were
around 4.9, in the potassium chloride solutions they were approxi-
mately 5.7. Watermelon seeds produced corresponding P, values
of approximately 5.0 in the magnesium sulphate solutions and 4.1 in
calcium nitrate solutions. Seeds of other species produced similar
differences in the P, values of the solutions of the different salts.

It will be observed that the initial H-ion concentration of the
solutions of each salt increased slightly with the progressive decrease
in the total salt concentration, but the P, values of the solutions
after soaking the seeds in them for fifteen hours showed a striking
similarity in value, except in the very dilute solutions. With a
few exceptions the seeds were incapable of bringing about any
marked reaction changes in the very dilute solutions (0.01-0.001
atm.), behaving in these solutions in somewhat the same manner
with respect to changes in reaction as they did in distilled water.

218 BOTANICAL GAZETTE [OCTOBER

The effect of the seeds upon the H-ion concentration of the
solutions in which they were immersed is strikingly shown in the
case of the potassium carbonate solutions. The P, values of these
solutions were well above 9.8. After fifteen hours’ immersion,

TABLE II

SEEDS IMMERSED IN MGSO, FoR DIFFERENT PERIODS, RINSED IN DISTILLED WATER,
THEN PLACED IN FRESH SOLUTIONS CORRESPONDING TO THE OLD

P,, values Atmospheres
7 | 6 | 5 | 4 | 4 2 1 | 05 | 0.2 | 0.04 |o.00r | 0.00
Corn

ee a at 6.5| 6.5| 6.4| 6.4] 6.31 6.3| 6.2] 6.2] 6.1| 6.1| 6.0] 6.0
nite cies We hens eats a1) Act Asal A. oA TAC Ul Aid! 4. th 4G) at) 4p 5-9

After s hours. 650.3. | AL2A AR Acer el AN AT) a eal Bid a Sd 58

Afters hours. i202 34: . 4.1 4.3) 4.31 4:1) 4.11 4.01 3.0} 3-01 3.01 4:01-4.91 5.9

After is hours. oc, 4.1} 4.1] 4.0} 3.9] 3.0] 3-9] 3.9] 3-9] 3-9] 4-1] 4-9] 5-9

After 18 hours.i.... 4... 4.1] 4.1] 4.01 3.9} 3-9] 3.9] 3-9] 3.8] 4.1] 4.21 5.0] 5-7

Alter oy hour. 0.4 3, 4.1| 4-1) 3.9 3-9} 3-9 3-9 3-9) 3.9) 3-9] 4-1] 4.9 5.6

Rinsed and placed in fresh solution

Hitil eS 6.6] 6.5] 6.5] 6.4] 6.4] 6.3] 6.2] 6.2] 6.1| 6.1] 6.0] 6.0

Alter DOU 5, AcSL 4.4 ACT ATL AL) 4.0) Ai Tl ACT AN ALO) 4. OF 50

After 21 hours......... AX 4:0) 4.3, 4.34.8) Alt ACT AS) 6. 0) 4-2) 2 Se

te nous 4-I} 4.0] 4.0] 4.1] 4.0] 4.0] 4.0] 4.0] 4.0} 4.2] 4.9] 5-7

Buckwheat

Tey pe ne 6.5] 6.5] 6.4] 6.4] 6.4] 6.3] 6.3] 6.2] 6.1] 6.1] 6.0) 6.0

pose anes Sore ears S72 So3) 8221-5. 315: 2 SiS) 5.4) Scat SOF 5. 1-5-9) 89

SY BOUT. 55 vo 5-21 4.9] 4.9] 4.0] 4.7] 4.9] 4.9] 4-9] 5-1] 5-3) 5-5] 5-7

After 40 hours......... 3) 5.0} §.2] 5.4] §. 4) §.3| 5.31 5-4] §-81 5:5] §:71 5-8

and placed in fresh solution

SNA ear er 6.6] 6.5] 6.5] 6.4] 6.4] 6.3] 6.2] 6.2] 6.1] 6.1] 6.0] 6.0

After. Boer oi ceck: 5-1| 4-9] 4.9] 5-0] 4.9] 4.9] 4.9] 4.9] 4.9] 5-1] 5-5] 5-9

After 5 hours... -..7:.- 4.9] 4.9] 4.9| 4.9] 4-9] 4.9] 4-9] 4-9] 5-1; 5-1] 5-5] 5-9

After 15 hots; 26.33 2% 5.0} 5.0] 5.1| 5.0] 5.0] 5.0] 5.1] 5.0] 5.0] 5.5] 5.5] 5-8

lupine seeds brought the Px values of these strongly alkaline solu-

tions below the neutral point in concentrations below three atmos-

pheres, and to 7.5 in all the higher concentrations. Both corn and

rape seeds immersed in the solutions of low concentration of this

salt also increased the H-ion concentration to such an extent as
to bring the P, values below the neutral point.

1922] RUDOLFS—SEEDS 219

The maximum reaction change which the seeds were capable of
bringing about in the small quantities of solution here used (100 cc.)
was accomplished in a comparatively brief period of time, as is
shown by the data in table II. Fifty corn seeds or fifty buckwheat
seeds immersed in too cc. of magnesium sulphate solution, with
osmotic concentration values of 7.0 atmospheres or less, produced
the maximum reaction changes of which they were capable during
an interval of one hour or less. The rate of reaction change of
course is determined by the amount of solution used, total salt
concentration, the number of immersed seeds, temperature, etc.

After the maximum reaction changes which the seeds were
capable of bringing about in the solutions had been attained, the
P, values then remained approximately constant for an indefinite
period. When the seeds were removed from the old solutions,
rinsed with distilled water for a few seconds, and placed in fresh
solutions with corresponding concentrations of the same salt, the
phenomenon of reaction change again took place and continued
until the maximum H-ion concentration was the same as that
previously produced. The final P, values with corn in magnesium
sulphate solutions were 3.9 to 4.2, except in the very dilute solutions,
always varying slightly on account of differences in temperature
and other environmental factors. ‘The seeds may thus be immersed
several times successively in fresh solutions, the reaction changes
taking place each time, but always bringing the final P, values to
approximately the same point, which is fairly definite for each
species in the solutions of a given salt, until finally the absorptive
capacity of the seeds is exhausted, and equilibrium is established
between seeds and solution.

The exact cause or causes of the rapid reaction change of the
solutions as indicated by changes in the P, values has not been
determined with absolute certainty. There are without doubt
several contributing factors, but all the experimental evidence thus
far produced appears to indicate that the primary factor, and the
only one which could account for the rapid reaction changes in the
single salt solutions here used, is that directly related to ion absorp-
tion by the seeds, the H-ion concentration increasing as the cations
are removed from solution by absorption at a more rapid rate

220 BOTANICAL GAZETTE [OCTOBER

than the anions. This is in accord with the work of PANTANELLI,$
who concludes from his extensive researches that salt intake by
the cells of living plants is an absorption phenomenon of single
ions, and he attributes the reaction changes of solutions in contact
with the roots of green plants to the fact that some ions are absorbed
at a more rapid rate than others.

That the materials excreted by the seeds in contact with the
solutions here used can have little influence in bringing about the
rapid increase in H-ion concentration, is indicated by the fact that
seeds immersed in distilled water, under conditions similar to those
under which they were immersed in the single salt solutions, did
not bring about any marked reaction changes, even when the seeds
were in contact with the solutions during a period of forty hours.
This is shown by the data in the last columns of tables I and II.

The rates at which these reaction changes take place and the
factors influencing them, together with a study of salt solutions of
a wider range and of a number of mineral and organic acids will
be the subject of a later report.

LABORATORY OF PLANT PHYSIOLOGY

N.J. AGRICULTURAL EXPERIMENT STATIONS
New Brunswick, N.J.

5 PaNTANELLI, E., Uber Ionenaufnahme. Pringsheim’s Jahrb. Wiss. Bot. 56:
689-733. 1915.

CURRENT LITERATURE

BOOK REVIEWS
Biology of aquatic plants

The writer of this interesting volume? has rendered a service to botanists in
summarizing and bringing together the extensive but widely scattered work
that has been done on aquatic seed plants. Mrs. ARBER’s work, however, is
far more than a compilation, for every chapter contains interpretive portions,
and in many of them the summary of the literature is but a scaffolding for
further records or conclusions. Certain chapters are greatly enriched by the
author’s own experimental and philosophical conclusions.

Members of this biological group are of special interest because of their
double specializations, first as terrestrial plants that have achieved flowers and
seeds, and secondly because of the more or less marked modification of struc-
ture and reproductive method as now related to the aquatic environment.
The volume will be of interest to all botanists, for the subject matter is ably
grouped around fundamental biological topics, many of them most favorably
illustrated by aquatic Angiosperms.

Part I deals with water plants as a whole, and takes up typical life histories,
starting with a biological classification of hydrophytes in relation to water and
substratum. The author then proceeds to discuss the vegetative structure of
typical aquatics, including the marine Angiosperms, which are discussed in the
concluding chapter of this section. In Part II the anatomy of leaves, stems,
and roots is considered, together with modifications of the external form of
these organs. The development of turions, or winter buds, is discussed, and
the later portion of this section takes up flowers, pollination, fruits, and seed
dispersal. Part III presents an analysis of the cheebieial ‘oudiitions of the
water habitat and the application of these to aquatic plants. This section is
concluded by a chapter on the ecology of hydrophytes, which is conservatively
handled, a topic which in the hands of some might perhaps have given title to
the book. Part IV is concerned with philosophical discussions dealing with
the dispersal and geographic distribution of water plants, their possible origin,
and their relations to the theory of natural selection. The — chapter
involves a summary of the author’s work on the phyllode theory

e volume is attractively printed and illustrated by 171 text figures,
Sana of them original. The bibliography occupies seventy-two pages,
and is made fully available by means of an appended index to the genera and

ARBER, AGNES, Water plants, a study of aquatic Angiosperms. 8vo. pp.
xvi+436. he. 171. Cambridge University Press, England. 1920.
221

222 BOTANICAL GAZETTE [ocTOBER

families of plants named in the literature. This is in addition to the general
index for the volume as a whole.—R. B. WYLIE

Chemistry of vegetable cell
A valuable service has been rendered to students of plant physiology by

conditions in Europe. This does not mean that the text is already old, for the
delay has permitted a revision since the war, and much new material has been
incorporated, particularly that which has been the result of discoveries in the
laboratories of Europe. Any failure to note foreign results is excused by GRAFE
on the grounds of the great difficulty vs tocar in keeping in touch with the
scientific production of other nations.

The subject is presented under five main headings: the physicochemical
laws of cell phenomena; light and heat as energy factors; the cell wall; the
protoplasm; and dynamic chemistry. The first two sections occupy about a
fourth of the text, and survey the problems of diffusion and osmosis, colloidal
state, imbibition, adsorption, electrolytic dissociation, energy transformations,
and catalysis. The third section is the briefest one, and deals with the struc-
ture, composition, and chemical transformations and modifications which occur
in the walls of cells during development and maturation.

The section on protoplasm considers its colloidal structure, chemical
constitution, the enzymes, toxins, precipitins, and pigments of the cell, par-
rl

brief consideration of stimulus and response, closing with the constructive
energy-storing processes.

The book is intended as a general text for students, and the author has
written in a style that is commendable for its clarity and directness. The
literature list at the end of the volume occupies twenty double column pages,
and the total number of references is nearly a thousand. Some of these refer-
ences are not considered in the text of the volume, but are included for those
who desire to orient themselves with reference to the literature on cell chem-
istry.—Cuas. A. SHULL.

Poisonous plants

A textbook dealing with the poisonous plants and weed seeds of Canada

and the Northern United States has been prepared by Tomson and SIFTON.

2 GRAFE, a Chemie der Pflanzenzelle. 8vo. pp. viii+-420. figs. 32. Berlin:
Borntraeger. 1922
3 THOMSON, R. B., and Srrton, H. B., A guide to the poisonous plants and weed
seeds of Canada and the northern United States. 8vo. pp. 169. figs. go. dercba
of Toronto Press. 1922.

1922] _ CURRENT LITERATURE 223

It is intended to meet the needs of the veterinarian, the farmer, the stockman,
and to a more limited extent the physician and the general public. The high
standing of the authors and the fact that they are botanists insure accuracy
so far as the plants are concerned.

The book is divided into four sections, the first three dealing with the plants
mainly responsible for fatalities among animals, grouped on the basis of their
occurrence in the animal’s feed, whether found in hay (section 1), in pasture
(section 2), or in concentrated feed stuffs (section 3). The fourth section
deals with the plants which, although poisonous, seldom cause the death of
animals. The larger number of poisonous plants, including those mainl

original an enab e the amateur to identify the plant responsible in an
ordinary case of poisoning. There is a “symptoms” key, not claiming to be
precise, but which will facilitate diagnoses by suggesting the plants which
should be looked for when certain symptoms are observed and plant poisoning
is suspected.

The authors emphasize the need for research on poisonous plants, both
along the lines of chemical analysis and feeding experiments. The book is
interesting and well written, and many of the observations, which could have
been made only by experienced botanists, indicate the propriety of issuing
Ts a book from a botanical department.—C. J. CHAMBERLAIN,

Constitution of vascular plants

CHAUVEAUD, in a small volume, has presented his views as to the constitu-
tion of vascular plants, based upon an investigation of ontogeny. He calls
attention to the disagreement between current theories and the facts he has
observed in his investigations. His conclusion is that the body of vascula
plants is built up by the successive appearance of fundamental units, or “phyl-
lorhizes.”” As one passes from Pteridophytes to Spermatophytes, the dis-
appearance of the root element (“‘rhize”) is more and more frequent, and
becomes the rule in Dicotyledons, where a rhize appears in connection with the
first two phyllorhizes, but appears in connection with later phyllorhizes only
in exceptional cases, as an adventitious root. In consequence of being thus
reduced to a single member, the root has acquired the power of enlarging
indefinitely and of persisting as long as the stem itself.

It is shown, also, that in the development of the apparatus of conduction
there is a eran parallelism between internal and external morphology, since
the aratus of the plant is built up by the repeated formation of
elementary iste each one corresponding ok ssp = the Phyllorhizes. ee
bud is the beginning of a new phy lo be added
In short, pl lants with rmed f: | tary plantules or phyllichizes,
and the constitution of these is the unit of morphology.—J. M. C

4 EAUD, Gustave, La constitution des plantes vasculaires révélée par leur
ontogénie. gion pp. 155. figs. 54. Paris: Payot. 1921. 10 fr.

224 . BOTANICAL GAZETTE [OCTOBER

NOTES POR STUDENTS

Taxonomic notes.—LiInDAUS has published the following new genera of
Acanthaceae from Colombia: Syringidium and Kalbreyeriella.

Naxaré has described eighteen new Japanese species of Viola.

Hircucock? has published an account of the grasses of British Guiana
based upon his collection during the autumn of 1919, and also upon the eollec-
tion of the Jenman Herbarium. The list of grasses thus far includes 169 species,
ten of which are described as new, four of them being species of Panicum.
Most of British Guiana is covered by virgin forest, with extensive upland
savannas only in the south. Of the 169 species included, thirty-three are
introduced, the greater proportion of these being in the vicinity of settlements.

rxon® has published an account of the mosses of the Wollaston Expedi-
tion to she New Guiana in 1912-1913. He states that “the moss flora of
New Guiana affords, perhaps, the most interesting field for the present day
bryologist. Large tracts of Central Africa remain no doubt comparatively
unexplored, and recent discoveries there show that much is still to be expected
of bryological interest.’”’ The report includes also some additional mosses from
British New Guiana. Among the species enumerated, twenty-three are de-
scribed as new.

Compton? has published an account of the plants collected in New Cale-
donia and the Isle of Pines in 1914. The Gnetales and Ginkgoales are absent
from New Caledonia, and the Cycadales are represented by a single species,
which occurs only in the littoral zone. On the other hand, the Coniferales are
developed to quite an exceptional degree, being represented by thirty-one
species, an unusually large number for so small an area. Another remarkable
feature of the coniferous flora is that apparently the whole of it is endemic.
The range of the Taxineae is extended to New Caledonia by the new genus
Austrotaxus, while the Cupressineae include the new genus Callitropsis.

Drxon’’ - described the following new genera of mosses, mostly from
Africa: Nanobryum, Chionoloma, Beddomiella, CEdipodiella, Chamaebryum,
Phosmibulehes and Dimorphoc

5 LINDAU, G., Neue er der Acanthaceen. Notizblatt Bot. Gart. Berlin-
Dahlem 8:142-144. 1922

6 NAKAI, ‘ecwame Violae novae Japonicae. Bot. Mag. Tokyo 36:29-39-
1922.

7 Hircucock, A. S., Grasses of British Guiana. Contrib. U.S. Nat. Herb. 22:
439-514. figs. 77-86. 1922.

n, H. N., The mosses of the Wollaston Expedition to Dutch New Guiana.
Jour. Linn. Soc. 45:477-510. pls. 28, 29. 1922.

9 Compton, R. H., A systematic account of the plants collected in New Caledonia
and the Isle of Pines by R. H. Compron in 1914. Part II. Gymnosperms. Jour.
Linn. Soc. 45: 421-434. pls. 26, 27. 1922.

10 Drxon, H. H., Some new genera of mosses. Jour. Botany 60: 101-110. pl. 564-
1922.

1922] CURRENT LITERATURE 225

Diets," in publishing an account of the Myrtaceae of Papua, describes
numerous new species, and establishes the following new genera: Xanthomyrtus
(14 species) and Octomyrtus (3 sgee The large genera are Jambosa (50
species), and Syzygium (44 specie:

GANDOGER” has published ne om part of a series of descriptions of new
species from various countries of the world. This first paper includes descrip-

from China, province of Yunnan. It is a tree or shrub, and in foliage and
inflorescence suggests certain species of Sterculia.
SARGENT“ has described twelve new species of Crataegus, chiefly from
Missouri and Arkansas
BLakeE’s has described forty-six new species of plants from Guatemala and
Honduras, from a collection made during 1919 by members of an Economic
Survey Mission sent out by the State Department. The new species are dis-
tributed among twenty-three families, and include two new genera: Decazyx
(Rutaceae) and Prosanerpis (Melastomaceae).
OBINSON,” in his further study of the Eupatorieae, has published seven-
een new species of Mikania - one new —— of rig ebaearen He has
published * local revisions of Mikani th America,
as follows: Colombia (32 a Venexiala (x5 spp.), Ecuador (18 spp.), Peru
(37 spp.), er Bolivia (28 sp
- Pipe oberon s the study of the woody flora of Korea, has
published an atone account of the Caprifoliaceae, accompanied by numero
unusually fine plates. Thirty-six species are recognized, distributed among
six genera, much the largest being Lonicera, with seventeen species. The
descriptions and discussions are in both Japanese and English, so that the pub-
lication is available for all taxonomists.

** Diets, L., Die Myrtaceen von Papuasien. Engler’s Bot. Jahrb. 57:356-400.
1922.
% GANDOGER, M. MICHEL, Sertum plantarum novarum. Pars prima. Bull. Soc.
Bot. — - 24-69. I 7 18.
W. W., ANS, W. Epcar, bgp a new genus of Sterculiaceae.
eee og Soc. Pesta - 69-71. pl. T. 19
™ SaRGENT, C.S., Notes on North American trees. IX. Jour. Arnold Arboretum
3:I-II. 1921.
1s BLAKE, S. inl New plants from Guatemala and Honduras. Contrib. U.S. Nat.
Herb. 24: I-32. 2.
** Roprnson, B. L., Records a ee to a general treatment of the Eupatorieae.
I. Contrib. tay ie rb. N.S. n
———,, The Mikanias of ete ae western South America. Jdem. no. 64.
pp. se 1922:
8 NAKAI, TAKENOSHIN, Flora sylvatica Koreana. XI. Caprifoliaceae, pp. 92.
pls. 42. Seoul. 1921

226 BOTANICAL GAZETTE [OCTOBER
Payson” has published a monograph of the genus Lesquerella, recognizing
nd s

examined are recorded in detail. Preceding the taxonomic presentation, there
is an interesting discussion of the general morphology, phylogeny, and. geo-
graphical distribution of the genus

PETCH,” in continuation of his studies of entomogenous fungi, has pre-
sented a very detailed account of Hypocrella and Aschersonia. In H ypocrella

t
thirteen species are described, four of which are new. In addition to the
species included in the systematic presentation, a number of species are named
as not seen, doubtful, or excluded.—J. M.-C.

rigin of variations.—Of extreme interest to students of genetics is a

recent number of the American Naturalist which contains the papers presented

at the Toronto meetings in a symposium on “The origin of variations.” JEN-

NINGS,”" discussing ° ‘variation in uniparental reproduction, ”’ stresses the fact
itiv

induced by environmental changes, which have always reverted to the normal
type after a certain number of asexual generations. JENNINGS points out that
the period of persistence of such variations evidently depends, in good part, on
the number of generations through which the producing agent acted, and .
expresses the belief that heritable characters, as permanent as any that are
known to exist, might be produced by allowing the producing agent to act over
a sufficient period of time.

BLAKESLEE” describes his work on Datura, which by this time has become
well known, showing how striking heritable variations accompany changes in
chromosome number. These changes in ch ber may result either
aia go ioaianiner of one or a few chromosome sets, producing “unbalanced

’ or may involve a wholesale doubling of all the chromosome sets, giving

#9 Payson, E. if hey monograph of the genus Lesquerella. Ann. Mo. Bot. Gard. 8:
103-236. figs. 34.
2 PretcH, T., pris in entomogenous fungi. II. The genera — and
Aschersonia, Ann, Roy. Bot. Gard. Peradeniya 7:167—278. pls. 2-5
31 JENNINGS, H. S., Variations in uniparental reproduction. i Nat. 56:
§-I5. 1922
LEE, A. F., Variations in Datura due to changes in chromosome number.
Amer. Nat. 56: 16-31. 1922.
3 Bot. Gaz. 72:178-182. 1921:

1922] CURRENT LITERATURE 227

the “balanced” tetraploid (or indirectly, triploid) types. The tetraploid types
breed true, but the others produce (in various proportions) several types of
progeny, including individuals like themselves and others like the “normal”
(pure diploid) original ancestors
MULLER takes up 5 Sy in the individual gene (“‘locus ie or true
mutations), and discusses their general characteristics. It is rtant to
realize that the change is not always a mere loss, for clear-cut reverse Sl nea
have been obtained in corn, Drosophila, and Portulaca, If the original muta-
tion was a loss, the reverse mutation must be a gain. “It is generally true
that mutations are much more apt to cause an apparent loss in character than
a gain, but the obvious explanation for that is, not because the gene tends to
lose something, but because most characters require for proper development a
nicely adjusted train of processes, and so any change in the genes, no matter
whether loss or gain, substitution or arrangement, is more likely to throw
the swyelopineatal mechanism out of gear, and give a ‘weaker’ result, than to
intensify it.” MuvLLER depicts a very interesting and suggestive analogy
between the gene and certain immunity reactions.
RIDGES’s elucidates the following very significant thesis. The characters
of an organism, instead of being absolutely “determined” by a single gene,
should rather be thought of as being acted upon simultaneously by many genes.

particular character will be determined by the equilibrium between its modify-
ing genes. The justification for this thesis appears from a consideration of
some of BrincEs’ non-disjunctional Drosophilas, which exhibit previously
unknown grades in the expression of a number of characters. Most startling
are the cases where the character involved is sex itself; so that the fruitfly, pre-
viously the best known example of qualitative differentiation of sex on the basis
of the X and Y chromosomes, now provides the most promiaing example of a
pearls sex mechanism with the newly discovered “intersexes” and
“supe

EMERSON” presents os classifies a great mass of slag on a variation.
He considers separately “somatic mutation of genes” and “ ic segrega-
tion,” and under the era heading ‘“‘ chromosome daalagtion” . toler
segregation,” and “graft hybrids and other chimeras.” This article should be

unusual interest to arenas
* Mutter, H. J., Variations due to change in the individual gene. Amer. Nat.

5632-50. 1922

*s BripcEs, CALVIN B., The origin of variations in sexual and sex-limited charac-
ters, Amer. Nat. 56:51-63. figs. 7. 1922.

6 Bor. Gaz. 72:408-410. 1921.

77 Emerson, R. A., The nature of bud variations as indicated by their mode of
inheritance. Keene, Nat. 56:64-79. 1922.

228 BOTANICAL GAZETTE [OCTOBER

GuYER*-draws the following conclusions from his own well known experi-
ments with white rabbits, and from the results of other investigations. Basic-
* : : : :

fundamental constituents under differing conditions of environment. There is
evidently some degree of constitutional identity, probably protein homology,
between the nature substance of a tissue and its correlative in the germ.
Changes which can affect certain constituents of tissue cells initiate an influence
which, borne in the circulating fluids of the body, evidently is able to affect
the homologous constituents of the germ cells. This, of course, furnishes the
basis for a Lamarckian view. The author feels that here may be a basis for
progressive evolution.—M. C. Coulter.

Influence of host on parasite.—Continuing his studies on the physiology of
parasitism, Brown” has investigated the exosmose of substances from leaf and

Lilium, Papaver, Iris, Petunia, Tulipa, Rosa, Begonia, Viola, Lathyrus (sweet
pea), Dahlia, Geranium, Cydonia, Pyrus, and on leaves of several plants, includ-
ing the broad bean. The change in the drops due to exosmose was determine
by studying their capacity for germinating spores added to the drops in water
suspensions, and also by electrical conductivity tests. Capacity for germinating
spores was based on the average length of the germ tubes. An increase in
conductivity resulted in all cases, accompanied in ie ie number of plants
studied by increased germination capacity, when the drops subjected to exos-
mose were compared with drops of distilled water of similar size. Petals diffi-
cult to wet gave lower conductivity and germination figures. In some plants,
with leaves of Tradescantia discolor, for instance, increased conductivity was
accompanied by germination capacity only equal to or less than that of dis-
tilled water, or by actual inhibition of germination. The exact source and
nature of the inhibiting substance were not determined.

Attention is directed to the difference in the behavior of fungal parasites.
Some, like the rust fungi, penetrate both susceptible and immune varieties of
plants, their ae thereafter being determined by internal conditions. Con-
trasted with this is the behavior of Botrytis spores on the leaf of the broad bean,
typical of another category of fungal parasites, in which the germination and
attack depend upon the exosmose of substances into cag infection drop, which
can be used as a nutrient by the fungus.—J. G. B

% Guyer, M. F., Serological reactions as a probable cause of variation. Amer.
Nat. 56:80-96. 1922.

29 BROWN, WILLIAM, Studies in the physiology of parasitism. Ann. Botany 36: 101-
119. 1922.

1922] CURRENT LITERATURE 229
Calamites.—Impressions. of casts of the external features of Calamites

plants. In all four of the large monographs now available on the Calamites,
by Stur, Weiss, Kinston, and especially JonGMANS, by far the greater number
of the figures relate to the pith casts. As a rule, examples of both medullary
casts and impressions showing the true external features of the stem are mixed
together in confusion, and are all referred to a common genus, Calamites.
Neither from the generic nor the specific names employed can one distinguish
whether one is dealing with pith casts or with the rarer external surfaces of
these stems. It is hardly necessary, however, to point out that incrustations
of the external features of the stems of these plants are of an entirely different
morphological nature from the medullary casts. For this reason ARBER ha
Proposed in 10916 : new form genus, Calamophioios, for the external stem
impressions, with the exception of the very distinct type of Dictyocalamites
which had been atone already in 1912.

and LAWFIELD® intend to establish a number of species of these
two new types, and they suggest that the same specific name may be used for
both types of preservations, the internal and external ones. They avoided
adopting new specific names for the types of Calamophloios, therefore, as
compared with the pith casts. The authors also succeeded in carrying out
a correlation of a number of external surfaces and pith casts of Calamites.—
A. C. Not

Pliocene flora of Varennes.—The Pliocene flora of Varennes is the subject
of a monograph by De La Vautx and Marty,** which is divided into the
following sections: (1) geology of the fossiliferous beds of Varennes, (2) a critical
study of the fossil plants of Varennes, (3) a description of new species discovered
in the deposits of Varennes, (4) paleontological, stratigraphical, botanical,

i chapter o i

Varennes is added. Of the forty-seven genera which are described in
— siseaah of Varennes, aa — sae to twenty-three Satie ae
Fourteen new species were established.
Ecologically, the flora oe Gansu indicates a temperate climate, because
of the thirty-seven definite species found at Varennes, thirty-four belong to
the temperate zone. This flora also contains more continental than insular
species. Almost all the species which tort the flora of Varennes, - hoses
nearest living relatives, inhabit at p

» ARBER, E. A. NEWELL, and LAWFIELD, F. W., On the external morphology of
the stems of Calamites, with a revision of the British species of Calamo
Dictyocalamites of Upper Carboniferous age. Jour. Linn. Soc. 44:507-530. pls. 23-25.
1920,

* De La Vautx, Rotanp, and Marty, Pierre, Nouvelles recherches sur la
flore fossile des environs de Varennes. Rev. Gen. Bot. 32:282-300; 327-336; 351-
68. 1920

230 BOTANICAL GAZETTE [OCTOBER

of southern Europe, Asia Minor, Japan, and the central states of the United
States. This zone follows approximately the fortieth degree of northern
latitude, and indicates an annual average temperature of 12-14°C. Since the
Miopliocene, during which the fossil plants of Varennes lived, the most of its
components have emigrated toward the south. The plant deposits of Varennes
accumulated in a lake, into which the ashes of a volcano fell.—A. C. No

Fossil plants from Missoula region—A paper by JENNINGS® deals with
some fossil plants from beds which are believed to be of Oligocene age. The
fossil plants consist of impressions of leaves and of leafy twigs, there being
also some impressions of fruits and leafless twigs. The Missoula specimens
are embedded in fine-grained volcanic ash which preserved the finer venation
of the leaf surfaces. Twenty-one species are enumerated, ten of which are
described as new, and one of which required a new name. Of the fifteen genera
represented in the Missoula flora, all but two are also represented in the
Florissant Basin of Colorado. The Missoula flora probably occupied the shores
and surrounding slopes of a high mountain lake. The climate was warmer,
and probably drier than that now prevailing at recent localities of similar
geographic position, like, for instance, the Flat Head Valley; and the vegetation
represented by the Missoula fossils ranged probably throughout a series of
associations from wet meadow to moderately xerophytic oak forests on rocky
or sandy shores. All of these vegetational associations were in close proximity
to the waters of a lake. There are eleven plates with excellent illustrations
in the book.—A. C. Nok.

_ Cycadofilicales——CaRPENTIER®’ presents a most interesting paper on 4
series aa Cycadofilicales fructifications which were from the Lower Carbo-
niferous of northwestern France. Two genera of seeds (Lagenospermum and
Carpolithus) have been observed, and in a number of instances pictured also-
Sporangia or microsporangia of Telangium, Pterispermotheca, and Diplotheca
are described. CARPENTIER concludes that the small seeds of Lagenospermum
and of related genera seem to have belonged to Sphenopteris, probably S.
Hoeninghansi and S. elegans. While the occurrence of Sphenopteris together
with seeds of Lagenospermum is frequent in the Westphalian of northern
France, the seeds of Neuropterides, which occur frequently in the Bassin de
Valenciennes, are very rare in the Bassin de la Basse-Loire. CARPENTIER
also emphasizes that our knowledge of the microsporangia of the Cycadofilicales
of Mouzeil and the Bassin de la Basse-Loire is still very rudimentary, only
fragments of male inflorescences having been discovered. ‘They seem to have
been of a very delicate structure. Telangiwm, or a nearly related genus,

3 JENNINGS, O. = Fossil plants from the beds of volcanic ash near Missoula,
Western Montana. em. Carnegie Museum 8:385-427. pls. 22-23. 1920.

3C gowns a l’étude des fructifications du Culm de Mouzeil
(Loire-inférieure). can Gen. Bot. 32:337-349. 1920

1922] CURRENT LITERATURE 231

originated in the Devonian and flourished in the lower and cate Culm in
Basse-Loire and during the Westphalian in the north.—A. C.

Availability of potassium.—BREAZEALE and Briccs* find that the potas-
sium of orthoclase solutions is not available for wheat seedlings, owing, it is
concluded, to the potassium being present with other elements in a complex
solute molecule, which does not yield potassium ions. This conclusion is
supported by the fact that oxidation with acids makes the potassium available.
From the experiments recorded in the paper, the general conclusions are drawn

cluded from experiments of this kind that plants cannot get the needed potas-
sium from finely ground orthoclase applied to the soil or from orthoclase found
naturally in the soil. The nature of the root system and the conditions of its
functioning are probably quite different in the solution than in the soil.—

Indian Gondwana plants.—A great majority of the specimens described in
this volume were figured by FrIstMANTEL in the Palaeontologia Indica. A
revision’s of the material brought to light some new features, and in several
instances has revealed inaccuracies in the illustrations accompanying FEtst-
MANTEL’s descriptions. Numerous text illustrations and seven plates in folio
with excellent drawings and photographs enable the reader to judge SEWARD’S
revision of Gondwana plants. SEWARD was ably assisted by SAHNI, who
promises to become an authority on Indian paleobotany.

The Gondwana system is an extremely interesting geologic period of high
Paleobotanic importance. It corresponded to the Permo-Carboniferous of

Tepresented, but ae peeya ae tiee are rather scarce. No Glossopteris is
mentioned.—A. C. N

New method of vegetative multiplication——Dastur and Saxton* have
described a method of vegetative multiplication in a perennial species of

4 BREAZEALE, J. F., and Briccs, L. J., Concentration of potassium in nage
solutions not a measure of its availability to wheat seedlings. Jour. Agri es.
20: nla 1921

Sewarp, A. C., and Saunt, B., Indian age plants: A revision of Palae-
ontologia Psat be New Series 7:1-42. pls. I-7.

and Saxton, W. T., A uew mth “ —_ multiplication

Da as
in Crotalaria burhia. "New Phytol. 20:228-233. figs.

232 BOTANICAL GAZETTE [OCTOBER

Crotalaria (C. burhria) which differs from anything previously described.
The plant has a very long tap root, and when about a year old the axis becomes
ribbed, the ribs beginning at the transition region between stem and root and
extending in both directions. The ribbing is associated with the development
of an accessory bundle system, and the gradual separation of branches which
become established as separate plants. In this way, ‘‘when the main axis
perishes, a circle of branches separated to below the ground level is already
established.” It was also observed that although the plant iby during most
of the year, it seems seldom to develop seeds.—J. M. C.

Sexual evolution.—ScHAFFNER*’ has presented his conception of the evolu-
tionary stages of sexual expression, defining what may be called twenty-three
steps in evolutionary progress, each one illustrated by examples. He is con-
vinced that sex “‘cannot be associated primarily with special chromosomes.”
The general conclusion is reached that ‘the specific structures and functions
developed in the ontogeny of an organism appear to be conditioned on the
interaction of four fundamental influences: (1) hereditary factors, (2) influence
of environment, (3) progression of senility, and (4) presence of sexual states
in the living substance.”—J. M. C.

Mesozoic flora.—Brrry’s® fourteenth contribution to the Mesozoic flora
of the Atlantic coastal plain deals with the floras of the Eutaw and Ripley
formations. The article comprises an advance paper of the fuller material
to be described and illustrated in a professional paper of the United States
Survey (no. 112) which has meanwhile appeared. The larger publication
includes the Tuscaloosa formation besides the two groups mentioned.—
A. C. Nok.

North American flora.—Part I of volume 6 begins the presentation of
Phyllostictales by SEAveR. This ordinal name is used in place of Sphaeropsid-
ales, use the generic name Sphaeropsis “goes out of the order,” and the
ordinal name becomes untenable. In this first part the genus Phyllosticta is
presented, 300 species being recognized, only three of which are described as
new.—J.

Fossil woods of Queensland.—SAuni® describes and gives microphoto-
graphs of a number of fossil woods which range from fern stems throug
gymnosperms to angiosperms. The paper is a valuable contribution to the
study of Mesozoic woods.—. Nok

31 SCHAFFNER, J. H., sensi of sexual evolution in the plant kingdom.
Ohio Jour. Sci. 3 32: IOI-113.
38 Berry, E. W., Stare sts to the Mesozoic i me the Atlantic coastal

plain. XIV. Tennessee. Bull. Torr. Bot. Club 48:55—72.

# Saunt, Brepat, Petrified plant remains from the es ae Mesozoic and
Tenay formations. Queensland Geol. Survey. Publ. no. 267. pp. 48. pls. 5. figs 10-

VOLUME LXXIV NUMBER 3

THE

BOTANICAL GAZETTE

November I 922

PHYSIOLOGICAL STUDIES OF EFFECTS OF
FORMALDEHYDE ON WHEAT:
W. M. ATwoop
(WITH TWELVE FIGURES)
Introduction

Copper sulphate and formaldehyde have been most commonly
used as fungicides in the treatment of seed wheat. The choice
between the two has often been determined by local custom and
prejudice, while in other cases climatic differences have been thought
to be worthy of consideration in the selection. During the twenty
years, approximately, that formaldehyde has been used as a dip
or spray, as a gas (44, 53) or with steam (39), reports have differed
radically in the degree of favor with which it has been viewed.

One group of experimenters has reported injury to germination
or seedling vitality, or both, following the use of formaldehyde.
STEPHENS of the Sherman County Branch Experiment Station at
Moro, Oregon, has consistently reported injury in his station reports
since 1913 (50). In 1917 he noted that 18.5 per cent of the seed
wheat was killed. He has made the further important observation
that in many cases seedlings may progress in development but with
lessened vegetative vigor. HEALD and Wootman (31) found
germination reductions at concentrations of 30-40 gallons of water

* The project on which the present paper is based was financed under the Adams
Fund, to which acknowledgment is hereby made.

233

234 BOTANICAL GAZETTE [NOVEMBER

to the pint of formaldehyde. In Utah, Stewart and STEPHENS (52)
noted vitality reductions in wheat, barley, and oats, but thought
the advantages outweighed the injury. Mackie (37) of Cali-
fornia noted that seed stored after treatment uniformly showed poor
germination. Even with proper drying the tissues appeared hard-
ened, causing retardation and distortion of the young seedlings.
Varying degrees of injury have been reported by many different
investigators (14, 19, 20, 21, 22, 53, 57, 58).

On the other hand, formaldehyde has been approved in varying
measures by different investigators, some of whom recognized the
dangers and injury in some cases, but have felt that the advantages
outweighed the injury. The War Emergency Board of American
plant pathologists found little injury from formaldehyde except
when the concentrations were higher than the usual 1 part to 320
parts of water, or when the other common precautions in treatment
had not been observed. This work was based on the reports of
seventeen experiment stations, and is probably the most complete
and uniformly secured set of data available from so large an area
of country (35). Many other workers in America and Europe have
reported in similar vein (6, 16, 32, 36, 38, 40, 45, 51, 55).

Within the past two years two most interesting papers have
appeared, in which the possibilities of avoiding injury from formalde-
hyde treatment have been suggested. Braun (13) finds the injury
apparently much diminished by not treating the grain until imbibed
with water. It is believed that exterior disinfection is thus at-
tained, and a much less amount of formaldehyde enters the grain
under these conditions. Miss Hurp (33) believes that when seeds
are treated in formaldehyde and subsequently allowed to dry, the
polymer paraformaldehyde is deposited on the seed coat with serious
eventual injury. Here, instead of the “pre-soak,” we have the
recommendation of washing in water subsequent to treatment to
avoid the harmful paraformaldehyde deposits. With the work of
Miss Hurp there appears to be a better explanation than formerly
of the source of the injury of formaldehyde to seeds. Amid 4
wide diversity of opinions as to the value of the disinfectant,
and with differing recommendations for reduction in treatment
injury, it seemed altogether desirable that something be learned as

1922] ATWOOD—FORMALDEHYDE 235

to the exact nature of the effect exerted by formaldehyde on the

physiological processes of seeds, as shown by wheat. Accordingly,

the Oregon Experiment Station has been occupied in such studies,

during parts of the past three seasons, and inasmuch as local condi-

tions have necessitated the temporary discontinuance of this work,

it was thought well to report the results already obtained.
Experimentation

Wheat for these studies was kindly furnished by Mr. STEPHENS
of the Oregon Branch Experiment Station. In order that the
' behavior of this wheat in relation to formaldehyde might be known,
it was thought advisable first to determine the effect on germination
of varying the concentration and also the time of treatment. The
formaldehyde used was the ordinary commercial material, the
strength of which was determined according to the method outlined
by Haywoop and Srrx (30), and found to contain 39.3 parts per
hundred by volume of the formaldehyde gas.

In the studies of the effect of varying the time of treatment, the
period was varied from 5 to 300 minutes of soaking in formaldehyde
1-320. The number of seeds used was 10,800, one-third being
grown in blotters in the customary manner, one-third in soil in
porous clay germinators indoors, and one-third outdoors in pots of
soil exposed to the weather and a temperature between 40° and
60° F. The indoor samples were grown in the laboratory, and, as
might be expected, germination was much more prompt at the
higher temperature. It was found that the time of dip between
twenty and forty minutes only slightly reduced the germination
percentages. A somewhat greater drop in the curves (figs. 1, 2)
occurs as the time is lengthened up to four hours, although the drop
is not great in most cases. The seeds germinated in soil displayed
a somewhat greater percentage of injury, as measured by appearance
above soil, than was true of the samples grown in blotters. This
difference between the behavior of formaldehyde treated seeds when
germinated in soil and in blotters was noted by CRANEFIELD (20) in
studying the effect of the fungicide on oats. He found the injury
in oats grown in the soil averaged four times greater than that of
seed grown in blotters. The explanation of this difference in

236 BOTANICAL GAZETTE [NOVEMBER

apparent injury was given by WALLDEN (56), who thought injuries
to the coleoptile, making it difficult to pierce the soil, do not prevent
the germination of seeds in blotters. Miss Hurp (33), after making
a similar observation, expresses preference for the blotter studies,
which she believes:show more clearly the distortion incident to

MIN. 0 60 120
TIME

1.—Effect of time of soaking wheat on Aaesgr germination, Hybrid 12
i pst Moro, Oregon: solid line shows percentage germination in blotters, sec
lines in soil indoors and outside; formaldehyde mixed 1-320 parts of water; summary
of 3600 seeds tested.

injury, even though the percentage stand which would be attained
under field conditions by this method could only be estimated.

In varying the concentrations of formaldehyde, treatment was
for ten minutes at 20° C., and the concentrations were varied from
40 to 320 parts of water to 1 part of formaldehyde. Uniform
dropping in germination occurred in all cases with increasing con-
centrations. As compared with the water dipped controls, there
was little injury apparent at the usual concentration of 1-320;
but with a concentration of 1-160 the germination curves began to

1922] ATWOOD—FORMALDEHY DE 237

fall, and at 1-40 the germination was cut from 40-60 per cent, both
in the blotters and in the soil. Here again, as in the previous
series, the injury was greatest in the outdoor soil, less in soil indoors,
and least of all in the blotter tests (figs. 3, 4).

Formaldehyde readily forms various polymers (8, 25). On
standing in the cool a flocculent white precipitate forms readily,

[ec
~
Beri
90/—— nei
~~. ae Ns el
ag -
OUTSIDE — a oe :
i a en Panta” a
To vo &.
Pee ‘Sten 4
a“
bf “>
a 7 Pea
s
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he
70
5H
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240

MIN 0 30 120
4 TIME

Fic. 2.—Effect of time of soaking wheat on perentige Seaniaston, Turkey Red
wheat from Moro, Oregon: solid li blotters, broken
lines in soil serine and outside; formaldehyde mixed 1-3 20 parts of water; summary
of 3600 seeds tes

or on concentration of the commercial solutions. This is ordinarily
referred to as paraformaldehyde, although the various polymers are
probably often found more or less associated, and means for the
identification of the various forms are not well known. Efforts
have been expended toward developing methods to prevent such
polymerization (28), but these methods have not been adopted in
general. If wheat is dusted with the white flakes of this so-called
paraformaldehyde, serious injury results. Turkey Red so treated

238 BOTANICAL GAZETTE [NOVEMBER

gave in one series of tests 9.5 per cent germination in blotters and
15 per cent in soil, as compared with 93.5 and 93 per cent respec-
tively for the controls. This effect of the white polymer on the
grain was noted by Coons and McKinney (19), who found that it
does not readily air out of grain but persists on it, so that its pres-

ee ————— Ps

-—"|\
oe oe el —
ee ee eae a ae ae nn. ae

‘
dd oA ~~
3 ee
vs ~N
ae ‘
x
N

1 To 320 160 80. 40

Fic. 3.—Effect of varied concentrations of formaldehyde on percentage germina-
tion, Hybrid 128 wheat from Moro, Oregon: solid line shows percentage for seeds
gain seh in blotters, broken lines for seeds in soil outside and indoors; ten minutes
of so g; summary of 3000 seeds teste

ence could be demonstrated by an indicator after the grain had
been exposed to the air of the laboratory for many months. Miss
Hurp (33) later has emphasized the extreme importance of the
polymer as the possible channel through which injury from formal-
dehyde ordinarily results.

PERMEABILITY
It was recognized that it must be determined whether formalde-
hyde actually penetrates the coat of wheat. It has long been known
that the seed coats of many seeds exhibit varying powers of exclu-

1922] ATWOOD—FORM ALDEHYDE 239

sion. Brown (15) showed this to be conspicuously the case for
barley, while SHutL (49) found semipermeability of seed coats a
rather general situation. SCHROEDER (47) showed that the coat
of wheat is permeable to the entry of mercuric chloride, iodine,
alcohol, ether, chloroform, and acetic acid when in water solutions.
Injury to the seed coat destroys this seed coat power of exclusion.

‘
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L
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4

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! To 33 8
CONCENTRATION

Fic. 4.—Effect of varied concentrations of formaldehyde on percentage germina-
tion, Turkey Red wheat from Moro, Oregon: solid line shows percentage for seeds
germinated in blotters, broken lines for seeds in soil indoors and outside; ten minutes
of soaking; summary of 3000 seeds tested.

Miss Hurp (34) found that injuries from the entry of fungicides
are much worse when seed coat cracks exist over the embryo.

Two methods were employed in studying the relation of the
seed coat of wheat to formaldehyde entry. After various diffi-
culties in technique, at the suggestion of Dr. E. M. Harvey, the
method was finally adopted of sealing the seeds one at a time to
the end of small glass tubing, into which formaldehyde solution was
placed. After allowing the seed to be in contact with the solution

240 BOTANICAL GAZETTE [NOVEMBER

for 3-4 days, the dry tip of the grain exterior to the tube was sec-
tioned and treated directly with the Schryver formaldehyde reagent
(29). With long periods of exposure to high concentrations of
formaldehyde (1-8) penetration appears to be possible at either
tip of the grain or on either face. The second method employed
was to measure the degree of semipermeability of the seed coat
indirectly by determining the weight increase of the seeds when
soaked in distilled water and in formaldehyde respectively. For-

Ses es em
| | |
,
/ aie
_ AT Het a ae ia
el ae ae Sg) S| i
an ez
oe —— 5
, ae oo f
4
4
a 4
4 ,
F)
i
t
H
t
PENETRATION
HOURS 6 ny 47 1 2 247 29:

1G. 5—Comparative absorption by wheat of water and formaldehyde mixed

1 to 8 parts of water, Hybrid 128 wheat from Moro, Oregon: solid lines indicate per-

centages of weight increases when seeds were soaked in formaldehyde, broken lines
hen soaked in water.

maldehyde of high concentration (1-8) was used, in order to make
more conspicuous any semipermeability differences of the coat
toward the water and formaldehyde. In harmony with the results
of Brown (15), if seeds with semipermeable coats be placed in salt
solutions, water will be taken up by imbibition until the inwar

force is offset by the equal outward osmotic force incident to the
solution outside. If the two forces just balance each other, and
if the coats be perfectly semipermeable, further soaking of the seeds
in solution will not cause a rise in the curve indicating percentage
weight increase, and the curve will continue horizontal. On the

1922] ATWOOD—FORMALDEHYDE 241

other hand, if there is a gradual entry Stee eos

of the salt into the seed, the curve

will flatten out quickly, and after | S29ee23
changing the seeds back into pure Hwata st

water, the sudden and extensive rise e SSS
we INnEO +00

of the curve as the water enters will

be followed by a subsequent sinking
as the salt gradually diffuses out of

the seed again. In this way, by long
and careful soaking of seeds in water

and solutions of higher osmotic con-

ion, it is possi 2) $8885 S
centration, it is possible to determine re aa
‘ zi we

whether the substance in solution is »| 3] ssoagges

entering the seed coat. Frequent 4 aa Sw S

oe : SU ab? Geo

weighings are essential, each seed lot S| #§/S883R5

being dried of surface moisture with PS Be Bebeerte a

. . a * cal on)

filter paper at each weighing. After palewhunk a Be

*1° . 4 aomn to

the curves approach equilibrium, the ee 2] gags os

seeds in either solution are trans- EI eyes:
ferred to the other one, with special & & 3

attention to the behavior of the

renee BA pei dome ait he

‘ Slaacaa

curves at this reversal of solutions. baby inated
. . . * 4° An XHOoOnk yt

The weighings were made in tripli- Slagdaags
- + a a + om

cate with 3.5 gm. samples. Seven- SSR OOM
teen intervals, covering 292 hours of a Be ipa
ro AaAMrH WH

soaking, were followed by computa-
tion of percentages. A study of the

resultant curves (fig. 5) leads to the

ol HH AHH oO
conclusion that formaldehyde slowly
penetrates the seed coat, and tha Es | 3 S339
er . »" od ly Bie, Fas
when the grain is again transferred | a ese Ge tedes

to distilled water, the formaldehyde
gradually diffuses outward. These
results are shown in table I. The
variations at the time of reversal are
by no means so great, even with this

high concentration of formaldehyde, tees

ve as ae ae cae
He baat aes cea cee

PN ge age
ete jeeet ees Moat “alee:
Netty SNR hedonic anen
CW dee Saal igh ea:
ee, ie ae Ne

DATA ON PENETRATION AS SUMMARIZED IN FIG. 5; PERCENTAGE WEIGHT INCREMENTS AT VARYING PERIODS OF SOAKING OF WHEAT

* Figures printed in heavy type indicate soaking in formaldehyde; others in water.

242 BOTANICAL GAZETTE [NOVEMBER

as the writer (7) in earlier work has found to maintain with other
grains in the presence of gram molecular solutions of sodium
chloride. From the consistent behavior of these curves we must
conclude that formaldehyde penetrates the coat of wheat, although
such entry is slow. The work of BAKKE and PLAGGE (10) offers
interesting confirmation of these conclusions. In their work the
rate of entry of water and of 1-320 formaldehyde was compared.
After a dip of fifteen minutes they found the weight increase about
the same for the two, and concluded that water entry from 1-320
is not greatly different from the absorption of distilled water. The
question of the comparative entry of water and of formalde-
hyde solutions becomes specially interesting in the light of
Cottis’ (18) work with barley, which indicated that the entry of
solutions, and hence the seat of selectivity, is in the germ end of
the grain.
DIASTASE

In order to determine the effect on starch digestion of the
presence of formaldehyde, a series of twenty-six test-tubes was
filled each with 10 cc. of 25 per cent soluble potato starch solution.
To all but two of the tubes 1 cc. of a filtered solution of Merck’s
medicinal diastase of o.5 per cent concentration was added. To the
test-tubes was then added 4 cc. of a formaldehyde solution varying
in concentration from 1-1000 through 1-400, 1-320, 1-240, 1-160,
1-80, I-40, I-20, I-10, 1-1, and pure 40 per cent commercial formal-
dehyde solution. Each condition was run in duplicate. These test-
tubes were then incubated for 1.25 hours at 40°C. It was presumed
at the beginning of these tests that it would be essential to determine
the percentage of reducing sugars as a measure of the degree of
digestion. It was found, however, that by modifying the methods
used by APPLEMAN (3) and SHERMAN (48), it was easily possible
to detect comparative differences in the amount of digestion by
the deepness of coloration of the solution upon the addition of
iodine. The stock solution of iodine as used eventually by dilution
ro cc. to 100 cc. of water was prepared with 1 gm. iodine, 5 gm.
potassium iodide, and so cc. water. In the series enumerated the
gradation of color was so obvious, from the deep blue of the check
to the clear solutions where digestion was complete, that the

1922] ATWOOD—FORM ALDEHYDE 243

experiment was tried of giving to each tube at the end of the test
anumber value. No digestion (as in the tubes lacking diastase) was
indicated by 10, complete digestion (no starch) by o, and inter-
mediate shades proportionately in between. It is not claimed that
this method equals the accuracy of colorimetric technique, yet the
differences were so pronounced that on checking over results with

NO
DIASTASE

FORMALDEHYDE EFFECT
ON
DIASTASE

at 1000 400 420 I il 0 40 620 j 9 BO

c CHECK

Fic. 6.—Effect of varying concentrations of formaldehyde on starch digestion:
height of lines indicates amount of starch remaining undigested (all conditions shown
in duplicate); 1 cc. 0.5 per cent solution Merck’s diastase, 10 cc. 25 per cent soluble
starch solution, and 4 cc. of varying concentrations of formaldehyde used in all but
controls.

other observers who were unfamiliar with the conditions presented,
it was thought that the situation did not justify the other method.
Referring to fig. 6, in which these values are presented graphically,
it will be observed that with the higher concentrations of formalde-
hyde the digestion is not greater in amount than that occurring in
the check containing no diastase. Commencing with the concentra-
tion of 1-20 of formaldehyde, and running from that point down to

244 BOTANICAL GAZETTE [NOVEMBER

1-400, there is increasingly greater digestion found (less starch
remaining). The question immediately arose as to whether the
result was inhibition or a retardation of the rate of digestion. This
was answered by running two series of digestions over a period of
four hours at the same temperature as in the previous tests. To

DIASTASE
SERIES
Tl ic "1 ¢ T € Tl ¢
+ 2. =. a a me ic, eo eg
tine 2 4 5 6
2

Fic. 7.—Time factor as related to starch digestion in presence of formaldehyde

ixed 1-40 parts water: — of line indicates amount of starch remaining undigested
(all conditions shown in duplicate); 1 cc. 0.5 per cent solution Merck’s diastase,
10 cc, 25 per cent soluble starch solution, and 4 cc. formaldehyde used in tests (7),
and a like amount water in controls (C); time periods in hours tests 1 to 6 respectively,
1.25, 1.5, 1.75, 2, 3, and 4 hours.

all the test-tubes of one series was added 1 cc. of the diastase solu-
tion, to one-half of the tubes was added 4 cc. of formaldehyde 1-49,
and to the other half (control) an equal amount of water. Ten cc.
of the 25 per cent soluble starch solution was placed in all tubes.
The second series was prepared in the same manner, except that
formaldehyde of 1-320 concentration was used. Four test-tubes
from each series were removed every fifteen minutes, two contain-

1922] ATWOOD—FORM ALDEHYDE 245

ing formaldehyde and two controls, and the iodine test applied
and results evaluated. Figs. 7 and 8 show that although digestion
is markedly checked by 1-40 formaldehyde at the end of the first
one and a quarter hours, digestion proceeds with further intervals
of time, so that by three hours the digestion which had been com-

DIASTASE

SERIES

eel

Fic. 8.—Time factor as —— to starch digestion i in presence of formaldehyde

mixed 1-320 parts water:
(all conditions shown in du plicate); 1cc. 0.5 per cent solution Merck’s diastase,
10 Cc. 25 per cent soluble starch solution, and 4 cc. formaldehyde used in tests (7),
and a like amount of water in — (C); time periods in hours tests 1 to 5 respec-
tively, 1.25, 1.5, 1.75, 2, 2.5 hou

plete in the controls in half that time, has also occurred in the
presence of the formaldehyde. The series in the presence of 1-320
(fig. 8) formaldehyde was not so striking, but nevertheless shows
satisfactorily that formaldehyde does not entirely inhibit the action
of diastase, but retards the same. Turning to the effects on the
starch digestion in living wheat of the concentrations of formalde-
hyde 1-320, 1-240, 1-160, and 1-80, a considerable quantity of

246 BOTANICAL GAZETTE [NOVEMBER

grain was treated to each concentration ten minutes, allowed to
drain, stand moist for two hours, and then thoroughly air dried
before an electric fan. The grain was then thoroughly ground in
a mill, and extracts of 8 gm. lots made in 100 cc. of redistilled water.
Ascending quantities of the water extract were then added to test-
tubes each containing 5 cc. of soluble starch prepared as for the

STARCH DIGESTION

Fic. 9.—Effect of formaldehyde treatment on diastatic activity of wheat extract,
seeds treated 10 minutes; concentration of formaldehyde used in treatment varied,
and also cubic centimeters of seed extract used: height of lines indicates amount of
starch remaining undigested after incubation one hour at 40°C.; 5 cc. 25 per cent »
soluble starch solution used in each test (all conditions shown in duplicate).

other tests. After incubation for one hour at 40°C. complete
digestion had occurred in the controls containing 5, 10, 15, and 20 CC.

respectively of the extract of untreated seed. Fig. 9 shows that
despite a few unexplained irregularities, the general trend is obvi-
ously a reduction in the amount of starch digestion, with a rise in
the concentration of the formaldehyde originally used in treatment
of the seed. This holds for 5, 10, 15, and 20 cc. seed extract tests

1922] ATWOOD—FORM ALDEHYDE 247

under all the conditions. From these data it would seem certain
that treating wheat with formaldehyde retards the availability of
carbohydrate to the germinating seedling. Boxkorny (12), review-
ing the work of NEUBERG, in which variations showed in the inhibi-
tory effects of different concentrations of formaldehyde ori various
enzymes and of the effects of the same concentration on different
enzymes, explains differences in behavior on the theory of the
molecular structure of the enzymes causing different linkages with
the formaldehyde. Inasmuch as enzymes are commonly known to
be associated at least with proteins, and as formaldehyde is known
to react quantitatively with amino acids, as in the Sdrensen titra-
tion, it is not surprising that effects of formaldehyde upon enzyme
behavior should be observed.

AMINO ACIDS

In the light of the results of the tests on the diastatic activity
effects of formaldehyde, it was thought well to determine the
relationships to amino acids. Miss CHoATEe (17) found amino
acids occurring in ungerminated wheat and increasing in amount
On germination. Miss EcKERSON (27) found only slight amounts
of asparagine in the ripened grain, although histidine, leucine,
asparagine, and arginine occurred during ripening. The chemic.
constitution of the wheat grain involves several linked amino acids
according to OSBORNE (42), while ABDERHALDEN and SAMUELY (1)
in a list of the amino acid constituents of gliadin of wheat flour give
alanine, tyrosine, and glutamic acid as among those highest in
amount.

As a preliminary test, known quantities of pure amino acids in
water solution were determined by the Van Slyke method, both
with and without the presence of varying amounts of formaldehyde.
Alanine was secured from the organic laboratories of the Eastman
Kodak Company, while glutamic acid hydrochloride and tyrosine
were purchased from the Special Chemicals Company of Highland
Park, Illinois. Careful checking through over 200 tests indicates
that such linkages as are formed by formaldehyde and amino acids
are broken by the Van Slyke process, and no reduction in nitrogen
yields occurred incident to the presence of formaldehyde. The

248 BOTANICAL GAZETTE [NOVEMBER

common use of the formol titration in the determination of amino
acids is based on our knowledge that such linkages do occur. It had
been assumed that in case such a combination between formalde-
hyde and amino acids of the germinating seedling does occur the
nitrogenpus nutrition might easily be disturbed. It is very much
hoped that the opportunity may be afforded later to check further
upon this point, and also to determine the comparative amount of
amino acids liberated in autolysis of treated and untreated seeds.

RESPIRATION

Much effort has been expended in the determination of the effects
of seed treatment upon the respiration. PErRce and co-workers
(43) correlated germinative vigor with respiratory activity. Carbon
dioxide has often been recognized as a measure of the activity of the
metabolism in the tissues liberating the gas. It was desired to
determine whether varying concentrations of formaldehyde, show-
ing varying effects on viability, also affected carbon dioxide releasal
in the same manner; in other words, whether the measure of formal-
dehyde injury may be had by the comparatively accurate carbon
dioxide measurements.

Seed lots of 75 gm. each in duplicate were soaked in water as 4
check, and lots in duplicate in the varying concentrations of for-
maldehyde, period of soaking being ten minutes, after which they
were drained and sealed in respiratory chambers submerged in a
constant temperature bath at 28°C. for two hours before begin-
ning the determination. Large museum jars were used for respira-
tory chambers, equipped with ground glass tops with openings for
two-holed stoppers. The seeds were suspended on wire gauze
six inches above the bottom of the chamber, while the tubing by
which the gases were withdrawn from the chamber during the tests
extended to the bottom of the jars. The water bath was 1.5 by
3 feet, and deep enough to permit the tall museum jars to be com-
pletely submerged in the water. Under the water bath were placed
six porcelain resistance units connected to the lighting system of the
laboratory. About 6 feet of small bore glass tubing was bent so
as to be submerged in the bath, and filled with mercury, which
served to conduct current from two gravity cells to a telegraphic.

1922] ATWOOD— FORMALDEHYDE 249

relay, which at the desired temperature turned off or on the heat
under the bath. This arrangement permitted control of the tem-
perature within o.2°C. Careful checking of the temperature at
different points in the bath indicated that stirring devices were
not necessary, other than the convection currents from the bottom
of the bath upward. Two chambers were used for water soaked
wheat (controls), two for the treated wheat, and two blanks to
permit checking against leakage.

After setting up the apparatus completely and before making
a determination, each of the six complete trains was tested by
suction as to its ability to hold up a column of mercury 10 inches
high without small leaks permitting the column to settle back again.
During the tests a gentle stream of air freed from carbon dioxide
was drawn through each outfit for the entire period of hours of the
run. In order that the rate of aeration might be uniform in the
various outfits, and ample to provide for several complete changes
of the air in the respiratory chambers during the course of the
experiments, the suction secured from a water pump was conducted
to the various chambers through tubing, connected to manometers
in such a way that after careful calibration of the separate manom-
eters, the rate of air flow could instantly be determined by a
glance at the height of the paraffin oil surface in the manometers.
Gas meters of this type were developed in connection with the
chemical investigations incident to the recent gas warfare work,
and are described in detail by BENTON (11). For each of the six
trains air was drawn respectively through 50 per cent potassium
hydroxide, a U-tube of moist soda lime, and through a barium
hydroxide indicator to detect any failure of previous absorbents to
remove all carbon dioxide. Air entered the respiratory chamber
at the top and was removed from the bottom under the wheat
arranged as described. The air then containing the carbon dioxide
released by the wheat was drawn immediately through a bead
tower containing fourth normal barium hydroxide, out and over
another barium hydroxide indicator before passing to the tube
connected to the water pump.

The amount of suction was regulated by ground glass stopcocks
between the pump and the last indicator flask. With the six com-

250 BOTANICAL GAZETTE [NOVEMBER

plete trains to provide for, it was not deemed practicable to apply
the type of automatic pipette arrangement used by BAILEy and
GurRjaR (9). Instead, a large bottle was thoroughly cleaned and
aerated with carbon dioxide-free air and filled with the standard
alkali. This reservoir was connected by tubing with a burette,
and communication with outside air protected by soda lime traps.
At the top of each of the bead tower columns was placed a separa-
tory funnel guarded by a soda lime trap. Before each running the
required number of cubic centimeters of the alkali were run directly
into the separatory funnel previously washed free of carbon dioxide.

When the whole outfit was ready to make a running, carbon
dioxide-free air was run for a sufficient period through the bead
tower column to remove all carbon dioxide, before admitting the
alkali from the separatory funnel directly into the bead column.
This method of determination of carbon dioxide is essentially that
described by TRuoc (54). Varying periods of aspiration in these
measurements were employed, although experience showed that
most satisfactory results could be obtained by employing a period
of from four to five hours. No results were considered worthy of
recording for second runs of any one lot of samples, as experience
showed the need of extreme care to avoid introducing errors inci-
dent to the growth of saprophytes upon the check samples, par-
ticularly if they were retained at 28°C. longer than one day.
BarLey and GuryjAR (g) allowed their moist wheat to stand several
days before removing the stagnant air for carbon dioxide determina-
tion. Had they used the temperature of 28°C., and had their
seed possessed a moisture content of 35-43 per cent, as was the case
in these tests, it would have been impossible to avoid questioning
the lary factor of saprophytes which these experiments showed
increased tremendously the output of carbon dioxide. Disregarding
the fact that they failed entirely to keep their chambers aerated
during the course of their work, however, it must be said that they
incubated their seeds at 37.8° F., and worked with seeds of moisture
contents much lower, in general between 12 and 20 per cent. NABO-
KICH (41) concluded that part of the carbon dioxide obtained in
plant respiration is incident to the same microorganisms that
vegetate on leaves and seeds. It was hence a source of much

1922] ATWOOD—FORMALDEHY DE 251

concern to avoid any fluctuations in respiratory results incident to
the gaseous exchanges of saprophytes which might easily be con-
fused with the results of seed treatment. NABOKICH, however,
determined that the respiration of microorganisms on seeds may be
disregarded during the first day, counting from the time of wetting
the seeds. It is thus believed that the data given here eliminate
the errors incident to such secondary factor.

Throughout the work over forty runnings were made, represent-
ing over 160 different seed lots. As regards the possible criticism
that the several per cent variation in moisture content based on
dry weight might make the results incomparable, it must be borne
in mind that absolute carbon dioxide yields of different runnings
are not to be compared with each other, but only the four lots
used in any one run. Careful analysis of the variations in carbon
dioxide output as related to moisture content has indicated that
these variations may not be ascribed to moisture content differences,
these observations being made in duplicate independently for the
four seed lots of any one running. Fig. 10 and table II summarize
the entire results of the investigations on respiration. In all of the
work care was taken to have present in the flasks and bead towers at
least twice as much of the alkali as would be neutralized by the
carbon dioxide liberated by the seeds during any one run. The
graphs are expressed in terms of the percentages of the barium
hydroxide neutralized. In each case 25 cc. of fourth normal
barium hydroxide was used, and at the close titrated against fourth
normal hydrochloric acid in the presence of phenolphthalein. If,
for instance, 12.5 cc. was neutralized the graph would express 50
per cent values.

Fig. 10 shows marked depression of the respiratory rate for the
highest concentrations (1-80) as compared with the water soaked
controls. The depression of the respiration rate is evident, although
decreasingly so, at 1-160, 1-240, and down to 1-320, the concentra-
tion usually used in seed treatment. At 1-400 and 1-1000 the
difference between the controls and the treated samples was neither
SO great nor so constant as to indicate any marked effects of the
formaldehyde on metabolism. Special care was used in checking
out the situation at the 1-320 concentration, at which point

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1922]

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254 BOTANICAL GAZETTE [NOVEMBER

evidently the concentration is near the border line of injury, since

1-400 does not definitely display such uniform depression of
respiration. It was desired to compare the respiratory rates of
young seedlings from treated and untreated wheat, but as yet
technique has not been devised which avoids the luxuriant devel-
opment of Rhizopus in the warm moist atmosphere of the
- respirometer. In these tests, as in those with the seeds alone,
special care was used to avoid air infection of the respirometers.
Just previous to a running, the interior of each jar was wiped out
with cotton moistened with mercuric chloride (1-1000). The
further precaution was taken of flaming the gauze on which seeds
and seedlings were placed. KKARCHEVSKI, as quoted by BAILEY and
GuRJAR (9), found the energy of wheat respiration as measured by
carbon dioxide releasal twelve times greater for the embryos than
for the entire seeds. This seems to indicate that the data may be
more largely influenced by factors affecting the embryos than other-
wise. The facts that formaldehyde denatures proteins, that the
embryo is rich in proteins, and that the respiration data show the
effects of formaldehyde treatment, make it possible that the injuri-
ous effects of formaldehyde are intimately connected with injury
to the embryo itself. This is in harmony with the findings of
CoLins (18), in a study of the coat of the barley grain, that the
entry of solutions and hence the seat of selectivity is in the germ
end of the grain.

It is of interest in this connection to note that although Miss
Hurp (33) believed the injurious effects of formaldehyde to be
attained by a slow absorption of the gas liberated from paraformal-
dehyde, and although these studies of the penetration of formal-
dehyde do not show any sudden penetration of the fungicide,
nevertheless within a period of time as short as three to six hours
during respiratory determinations, some effect is exerted upon the
seed which very definitely modifies the respiratory rate as compared
with water soaked controls. One can but wonder whether here,
as in the case of the studies of CRocKER and KnicuT (24), we may
not have in plant responses a more delicate indicator of injury
than are the chemical reactions commonly used in detecting these
injurious substances.

1922] ATWOOD—FORM ALDEHYDE 255

CATALASE

The work of recent years has shown that there often seems to
be a relationship between respiration of plant tissues and the
catalase content. APPLEMAN (4, 5) has shown this relationship in
the case of potatoes and corn, CROCKER and HARRINGTON (23) in
the case of seeds. The latter workers find that this relationship is
not universal, for while imbibed Johnson grass has its respiration
paralleled by the catalase activity, this is not true for the seeds
of Amaranthus. The most interesting observation is further made
that in the case of Johnson grass where this parallelism is found,
neither the respiratory activity nor the catalase content is paralleled
by the vitality of the seeds or the seedlings. Inasmuch as seed
vitality and seedling vigor are definitely related to formaldehyde
treatment, and this work has linked in also the effects upon respira-
tion, it was thought to be of interest to determine whether any
effects of seed treatment could be noted upon the catalase activity
of wheat.

Catalase activity in wheat was determined much after the
method suggested by APPLEMAN (2), and later employed with various
modifications by other workers (17). Two series of experiments
were conducted, one to see whether any effects of formaldehyde
could be noted immediately after treatment while the grain was
still moist, and another to see whether the effects of treatment
persist on grain which has been treated and air dried before an
electric fan in the laboratory and subsequently exposed for about a
month to the air of the laboratory. The concentrations of formalde-
hyde used were 1-80, 1-160, and 1-320. About 1 gm. of air dried
wheat was used in each case, weighed on the analytical balance, and
results computed to the basis of 1 gm. For a reaction chamber
a bottle of 250 cc. capacity was used and shaken continuously dur-
ing the ten minutes of the test by a mechanical shaker making 129
excursions per minute. The reaction chamber was submerged in the
constant temperature bath previously described, and was kept at
28°C. Dioxygen was used and neutralized with calcium carbonate.
It was found that 3 mg. of the chemically pure salt used would
neutralize 5 cc. of the peroxide, and this proportion was observed
throughout. The gas evolved was run into a too cc. gas burette,

256 BOTANICAL GAZETTE [NOVEMBER

and all readings corrected for temperature and barometric pressure,
the equivalent corrected volumes at o° C. and 760 mm. being
computed for 1 gm, sample. Ten cc. water and 5 cc. peroxide as
neutralized were used.

In the case of the freshly treated seeds, they were soaked for
ten minutes in the formaldehyde solutions, and kept moist for two
or more hours, until tested. The moisture of the seeds precluded

OxYGEn
cc.
3 CATALASE
20
iZ
|Z
\Z
|Z
Ty \Z |Z
Z Z | |
Z iA Z lg
gZ Z Z \Z
- Z WZ Z Z
Z NE g Z
2 ii g Z Z
Zz A iZ Z
BZ WZ | A
Z \Z Z
Z \Z Z
Z 1Z \Z Z
i cA 0
Z Wi Z BZ Z Z
a We Z ZY
TEST 1's 913 260M" a 7H 4ent 17 19 21 22 t@ 20 2224
Dee eee os
1G. a sv aeeect of formaldehyde in varying concentrations upon ability of see ed
extract to ga ei rom m dioxygen: height of lines indicates cubic conti
— of oxygen computed for
ex ract from water-soaked seeds (controls) erennye by white, ‘vertical lining indicates

1-320, diagonal lining form: 7 1-160,
and solid black formaldehyde 1-80; in all fli iar tested while still mois

the possibility of passing the material through bolting cloth (23),
but it was soon found that a material difference in the crop of
oxygen given off resulted if the seed material was more or less
glutinous and forming sticky masses, or dry enough to separate
fairly well on grinding in a mortar with carborundum as an abrasive;
hence all surface moisture was removed with filter paper before
grinding up the seeds. Inasmuch as differing moisture contents of
the differing lots would occur between the first lots tested and the
last in a long series, the errors incident to this cause were avoided

1922] ATWOOD—FORMALDEHY DE 257
as far as possible by testing consecutively the control seeds and those
treated with 1-320, 1-160, and 1-80. Suchaseries of four naturally
fall together for comparison in one group, and many such series
were made, the combined results of which may easily be seen from
fig. 11 and table III. With some small variations, the results were
surprisingly uniform in showing the steady depressing effect of

TABLE III
DaTA ON CATALASE TESTS AS SHOWN IN FIG. II

Concentration | Weight of Volume Tempera- ‘sired volume

Test no. formalin sample loeet Barometer ture treatment =

— and test pally

ee eae Water control] 1.015 | 30.1 748 24 2 25.9
BS a Water control} 1.005 26.9 748 24 ae 23.4
ey aes Water control| 1.006 23.5 74 25 7 20.3
fae ea cna ne control] 1.009 22.4 74 25 8.5 19.3
a eee I-320 1.008 21.8 74 24 2.5 18.9
Ge ey 1-320 E.000:4°= 20. 74 24 3-75 17-5
Pee 1-320 1.004 18.6 74 25 oes 16.1
Be cys I-320 1.002 | 17.6 74 25 9 15.3
is ee en eee 1-160 1.006 22.2 74 24 2.96 19.3
: {oN rae re I-160 I.O15 18.3 74 24 3 15.8
kp eas I-160 1.007 16-7 74 25 7-5 13.6
Ee eee Ea I-160 1.002 15.3 74° 25 9 13-3
ci Ma erin —80 I.O10 14.4 74 24 3 12.5
1 1-80 1.011 13°60 74 24 3 II.3

Moe. 1-80 i 10.6 L 25 8 9-20
Ps Bi Peo a 1-80 .610 1 11.9 74 25 9.5 9.63
sd eee eae Water control} 1.017 24.6 747 24.5 S 21.1
13 Water control} 1.012 22.3 745.5 25 7-75 19.1
i I-320 1.007 19.4 747 24.5 5 16.8
R00 e. I-320 1.O1o 4 3727 745-5 | 25 8.25 15-2
y 3 digest eel 1-160 1.003 16.7 747 24.5 §-25 14.5
Petes epee 1-160 T.01r |} 28-5 945.5 | 45 8.5 13-3
> fea ah ea —80 1,003 12.7 747 24.5 5-5 11.9
Ree 1-80 r.0r3 | 12-1 745-5 | 25 8.75 10.4

As the concentration of the

formaldehyde on catalase activity.
formaldehyde rose, the catalase activity as measured by oxygen
yield fell.

In the studies of the effects of formaldehyde on catalase activ-
ity after the seeds had been dried about a month in the labora-
tory, comparison was made only between the control and the
seeds treated in 1-80 formaldehyde. Fig. 12 and table IV show
that there is a definite depressive effect of the treatment on catalase
activity, but it is by no means so great as soon after treatment.

258 BOTANICAL GAZETTE [NOVEMBER

CATALASE

SEED SOAKED iM WATER

. WATER I> 80
TEST 36 37 38 40 41 42 43 4}

Fic. 12.—Effect of formaldehyde 1 to 80 upon ability of seed extract to liberate

compu and constant temperatures and pressures; extract of
water caker seeds (controls) indicated by ner treatment in 1-80 indicated by
vertical ruling; hinla ry
after treatment.
TABLE IV
DATA ON CATALASE TESTS AS SHOWN IN FIG. 12
; Correct
Test no. a — Oxygen (cc.)| Barometer | Temperature couvea: oe
1 gm. sample
Set ae Water control} 1.014 20 743.5 25 17.10
S62 is Water control I,002 24 743.5 25 20.
SPATS Water control} 1.005 22.5 743-5 a 19.5
ahi: Water peontetert 2 21.5 743.5 24 18.6
Pes 1-80 1.014 1S.7 743.5 24 13-5
485.003 ' 1.005 18,8 74 23 16.3
pt pe ee 1-80 1.002 17.5 74 23 15.2
Pt eae 1-80 1.020 72.5 74 23 13-3
pov 1-80 Zz; 18.5 rE 23 16.1
Se Water control I.O11 43.5 74 21.5 20.5
OT Perera Water control 1,011 24.2 74 20.5 21.2
PU gah ete Watercontrol| 1.012 26.1 rE 20.5 22.9
eS Water control} 1.014 25.9 74 21 22.6
Pe eee Water control 1.014 26.7 rE at.5 23.2
BOer eas: 1-80 - 20.0 74 21.5 17.6
ge eee 1-80 1.003 21.3 74 20.5 18.8
ce Bare 1-80 I.002 23.8 7 21 21.0
Ras io 1-80 I.OIL 21.8 74 $2.5 19.0
Lo ae 1-80 1.001 21.7 Ve 21.5 19.1

1922] ATWOOD—FORMALDEHY DE 259

This would seem to support the view that the injury is due more to
exterior members retaining the formaldehyde which had been vola-
tilized in part, than to a permanent injury to the embryo having
resulted from the treatment.

General considerations

The treatment of seeds with fungicides is a process wherein one
plant tissue (that of the parasite) must be destroyed, while another
tissue (that of the seed) must be conserved. It is entirely probable
that the points of fungicidal effectiveness and of danger to seeds are
not far separated. Dr ZEEuw (26), in noting this point, quotes
work in which it was found that the seeds were more sensitive to
formaldehyde than spores of either bacteria or fungi, when its
action was deeper than the surface, as is essential to secure sterile
seeds. He believes that the high concentrations of disinfectants
required to care for the destruction of bacterial spores is explained
by the protection afforded by the seed coat on which the spores
are lodged. There is an interesting similarity between this state-
ment and the findings of Retmer (46), who observed that in the
control of the bacillus producing fire blight of pears, a disinfectant
which is serviceable upon tools is ineffective when used upon the
organic substrate of the wood of the tree itself.

It would seem that we have been too ready to jump to conclu-
sions and give “‘recommendations”’ as to treatment upon the basis
of germination data of more or less extent. In the light of the
preceding results, it seems doubtful whether it is safe to postulate
the boundary lines of safe and dangerous concentrations merely
upon the basis of germination data. STEPHENS (50) has emphasized
the relationship of seed treatment to subsequent lowered vitality of
seedlings. It is thus entirely possible that concentrations which do
not materially injure germination percentages do materially disturb
the physiological processes related to germination and subsequent
growth. Common agricultural practice and the findings of the
War Emergency Board of American plant pathologists seem to
indicate that 1-320 is at the edge of the danger zone, if indeed such
zone is not here passed. If, as Miss Hurp (33) believes, a polymer
of formaldehyde is deposited on dried treated wheat, and subse-

260 BOTANICAL GAZETTE [NOVEMBER

quent injury to the grain is incident to the liberation of formalde-
hyde gas from the precipitate, with its resultant solution in the
moisture content of the living cells, the process must be a slow
cumulative one which is entirely in harmony with the definite
although slow entry of formaldehyde herein shown actually to occur.
Furthermore, even though the grain be treated with 1-320 formalde-
hyde, such a deposit of the polymers would result in the presenta-
tion to the living cells of a much stronger concentration than that
of the dip used. Yet even at the concentration of 1-320 it is
evident that while germination is often but lightly affected, the
diastatic power of wheat is retarded, the catalases are less active,
and respiration is definitely reduced. It is not impossible that
such results indicate a decided tendency to a reduction in seedling
vitality even in the presence of germination.

It is highly desirable that these studies be pursued further to
determine the relationship of treatment to the proteolytic activi-
ties of the germinating seed, and further, to determine whether the
recommended “‘presoak”’ of BRAUN (13) or the ‘“‘post-washing”’ of
Miss Hurp (33) correspondingly modify the physiological activities
and alleviate their injury.

Summary
1. Tests of formaldehyde entry into wheat have been made both
by microchemical tests and by imbibitional studies, indicating that
formaldehyde slowly enters through the seed coat.
2. Diastatic activity of the grain is retarded.
3. Respiration is slowed down.
4. Catalases are reduced in their ability to break down peroxides.

OREGON AGRICULTURAL EXPERIMENT STATION
CorVALLIS, ORE.

LITERATURE CITED

1. ABDERHALDEN, E., and SAMUELY, FRANz, Die Zusammensetzung des
*‘Gliadins” des shape Zeit. Physiol. Chem. 44:276-283. 1905.
Abs. in Jour. Chem. Soc. 88:6 1905.

2. APPLEMAN, C. O., Some OEE on catalase. Bor. Gaz. 50:182-
192. 1910.

, Physiological behavior of enzymes and carbohydrate transforma-

tions in after-ripening of the potato tuber. Bor. Gaz. 52:306-315. 1911.

1922] ATWOOD—FORM ALDEHYDE 261

Leal

4
=

4
oO

APPLEMAN, C. O., Relation of catalase and oxidases to respiration in plants.
Bull. 191, Md. Agric. Exp. Sta. pp. 16. 1915.

, Relation of seer and catalase to respiration in plants. Amer.
Jour. Bot. 32223-233. 19

. ARTHUR, J. C., Pocnaie a grain and potatoes. Ind. Agric. Exp. Sta.

Bull. 77:38-44. 1
Atwoop, W. M., A A physiological study of the germination of Avena fatua.
Bort. Gaz. 57: ei, 1914

. AUERBACH, F., and BaARSCHALL, H., Studies of formaldehyde. II. The

solid polymers of formaldehyde. Ad Kais. Gesundheitsamt. 27:183-
230. 1908. Abs. in Chem. Abs. 2:1125. 1908.

BalrLey, C. H., and Guryar, A. M., Respiration of stored wheat. Jour.
Agric. Res. 12: ie 715. 1918.

. BAKKE, A. L., and PiaccE, H. H., Studies on the absorption and germina-

tion of wheat treated with formaldehyde. Ia. Acad. Sci. 26:365-375. 19109.

. Benton, A. F., Gas flow meters for small rates of flow. Jour. Ind. and

Eng. Chem. 11: hale, 19

- Boxorny, T., Bindung pr Wormakicheds durch Enzyme. Biochem.
8:641

oe 94: boca 1919. Abs. in Bot. Abs.
Braun, Harry, Presoak method of seed ireatinent. Jour. Agric. Res.

i oO.
. BRITTLEBANK, C. C., The effect of formalin and copper sulphate solution

on the germination if wheat. Jour. Dept. Agric. Victoria 11:473-476.
1913.

own, ADRIAN J., On the existence of a semipermeable membrane
inclosing the seeds of some of the Gramineae. Ann. Botany 21:79-87.
1907

. BuRMESTER, H., Comparative investigations on the effect of various

methods of seed treatment on the germination of seed. Zeitschr. Pflanzen-
krank. 18:154-187. 1908.

Cuoate, HeLen A., Chemical changes in wheat during germination. Bor.
GAZ. 71:409-425. 1921.

. Cottins, E. J., The stricture of the integumentary system of the barley

grain in relation to the localized water absorption and semi-permeability.
Ann. Botany 32:381-414. 1918.
Coons, G. H., and McKryney, H. H., Formaldehyde injury to wheat.

21st Mich. Acad. Sci. Rept. 321-324. 1919.

. CRANEFIELD, F., The influence of formalin on the germination of oats.

Wis. Sta. Rept. paresee I9OI.

, The influence of formaldehyde on the germination of oats. Wis.
Sta. Rept: 268-272. 1902.

Treatment of seed oats for the prevention of smut. Wis. Sta.

» Ih SRE ATS
Rept. 363-367. 1903.

262

23.

w
:

BOTANICAL GAZETTE [NOVEMBER

CROCKER, WILLIAM, and HARRINGTON, GEORGE T., Catalase and oxidase
content of seeds in relation to their sina age, vitality, and respira-
tion. Jour. Agric. Res. 15:137~174.

. CROCKER, WILLIAM, and KNIGHT, ig L. Effect e rear gies: gas and

ethylene upon flowering carnations. Bort. Gaz. 46:259-276. 1
DELEPINE, MARCEL, Formaldehyde in gaseous nists and solid ipa and
in solution. Bull. Sci. Pharmacol. 16:146-160. 1910. Rev. in Chem.

. DE ZEEUW, RICHARD, The e comparative viability of seeds, fungi, and bac-

teria when subjected to various chemical agents. Centralb: Bakt. 2 Abt.
3134-23. 1912

ECKERSON, SopHtA H., Microchemical studies in the progressive develop-
ment of the wheat plant: Bull. 139, Agric. Exp. Sta. Wash. 1917.
Guarco and pees Preventing polymerization of formaldehyde. Rev.
in Chem. Abs. 3:220

909.
29. Haas, Paut, and Hus, T. G., An introduction to the chemistry of plant

fe
°

speihaies Longmans Green & Co. Citation page 149.

p, J. K., and Surru, B. H., A study of the hydrogen peroxide
method. ot deeper formaldehyde. Jour. Amer. Chem. Soc. 27:1183-
1188.

‘ Heat, ny Ly and Wootman, H. = ee or stinking smut of wheat.

Bull. 128, Agric: Exp. Sta. Wash. pp IQI5.
HENDERSON, L. F., Experiments Bt ak and oats for smut. Bull. 53,
Agric. Exp. Sta. Ideho, Pp. 15. 1905.

. Hurp, Annie May, Injury to seed wheat resulting from agin ike dis-

infection with formaldehyde. Jour. Agric. Res. 20: 209-244.

, Seed coat injury and viability of seeds of wheat “a ten as
factors i in susceptibility to molds and fungicides. Jour. Agric. Res. 21:
99-122. 1921

Jounson, A. 6, STAKMAN, E. C., and Porrer, ALDEN A., Preliminary
review of patty on seed injury tests with standard disinfectants. Report
from Office of Cereal Investigations, U.S. Bur. Pl. Ind. 1918.

Kress.inc, L., Experiments on the germ ripening of grain. Landw. Jahrb.
Bayern 1:449-514. IgII.

. Mackie, W. W., Progress report on cereal smuts. Smut control measures

practised in California. 1918 (unpublished).
McALPrInE, D., Effect of formalin and bluestone on germination of —
wheat. Bull. 12, Dept. Agric. So. Aust. pp. 21. 190

. Metuus, I. E., A quick method of eliminating seed borne organisms of

ain. Science N.S, 50:21. 1919.

gr
. Mvetter, H., and Motz, E., Experiments on the combating of stinking

smut in winter wheat by means of the formaldehyde treatment. Fiihlings
Landw. Z. 63:742-752. 1914. Rev. in Chem. Abs. 9:2122. 1915.

1922] ATWOOD—FORM ALDEHYDE 263

41.

42.

wm
i

ut
on

Nasoxicu, A. J., Uber den Einfluss der seepage : Samen auf die °
Atmung. Ber. Deutsch. Bot. Gesells. 21: 279-291.

OsBoRNE, THOMAS B., The proteins of the wheat ocak Carnegie Inst.
Publ. no. 84. pp. 119. 1907.

- Perce, G. J., Darste, M. L., and Exriorr, = A study of the germinating

power of seeds. Bor. Gaz. 58: IOI-136. I

‘ piso L., Bactericidal action of dry shiendcheds Ann. Inst. Pasteur

9: 701-719. 1908.

; lias G., On the germination of wheat treated with some fungicides and

insecticides. Coltivatore 59:435-439. 1913. Rev. in Exp. Sta. Rec. 30:
837. 1914.

. Remer, F. C., Unpublished work at the Southern Oregon Branch Station,

Talent, Oregon.

. SCHROEDER, H., The resistance of wheat and barley grains to poisons with

— ae to seed sterilization. Centralb. Bakt. 2 Abt. 28:492-505.

ak H. C., KenDALL, E. C., and Crark, E. D., Studies on amylases.
I. An examination of methods for the détéemination of diastatic power.
Jour. Amer. Chem. Soc. 32:1073-1086. 1910.

. SHULL, C. A., Semipermeability of seed coats. Bot. Gaz. 56:169-199.

1913

. STEPHENS, D. E., Unpublished annual saga from the Sherman County

Dry Farm ‘inch Station, Moro, Ore

STEVENS, F. L., Experiments upon the tie of formalin on the germina-
tion of oats. N. C. Agric. Exp. Sta. Rept. 30-36. 1

Stewart, R., and STEPHENS, J., The effect of Soren on the vitality of
seed grain. Bull. 108, Agric. Exp. Sta. Utah, 145-156. roro.

Tuomas, CECIL = sli disinfection by formaldehyde vapor. Jour. Agric.
Res. 1733-39.

Truoe, E., Methods for the determination of carbon dioxide and a new
form of abeorption tower adapted to the titrametric method. Jour. Ind.
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. Wattpén, J. N., Damage caused by threshing of wheat and rye and its

influence upon ‘sensibility to treatment with fungicides and to storage.
Sveriges Utsidesfér. Tidskr. pp. 24. 1917. Rev. transl. from Dept. Agric.
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Sveriges Utsadesfér. Tidskr. 22:242-252. 1912. Rev. in Exp. Sta. Rec.
28:242. I9I

Winviscu, R., Concerning the effect of formic aldehyde on germination.
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DEVELOPMENT OF THE GEOGLOSSACEAE
G. H. Durr
(WITH PLATES VIII~xII)
Introduction

Detailed knowledge of the ontogeny of Helvellinean fungi had
its beginnings in the work of Dirrricu (7), whose paper on the
complete development of Mitrula phalloides and Leotia gelatinosa
(L. lubrica), with observations on other forms, has been the start-
ing point for all subsequent life history studies in this group. This
worker found that in the early stages of growth the ascocarps of
Mitrula and Leotia possess a veil which, although evanescent, covers
over the hymenium during the early part of their history, and thus
renders their development endogenous. Heretofore the Hel-
vellineae had been regarded as an essentially exogenous order, and
SCHROETER (20) had separated them on this basis from the Pezizi-
neae, in which group the hymenium was considered to be developed
characteristically in a closed cavity which later opened. DURAND
(11) confirmed and extended Dirrricu’s observations in the intro-
duction to his excellent monograph of the Geoglossaceae. He states
that he had observed the veil of Mitrula phalloides before learning
of Dirrricn’s work. He had, in addition, noted the occurrence
of a particularly well organized veil in Microglossum viride, and the
conspicuous envelopes of Spathularia velutipes and Cudonia lutea.
Of the latter he published beautiful photographs, illustrating these
structures macroscopically.

The next contribution to this subject was a paper by McCusBBIN
(17) on the development of Helvella elastica. His work constitutes
the first study in the family Helvellaceae, all the previous work
having been confined to the Geoglossaceae. Here also it is stated
that a membrane incloses the ascocarp in the younger stages of the
form with which he worked. It is disorganized relatively early, and
the last traces of it are cast off with the appearance of the pa-
raphyses. Brown (4) follows with an account of the development
Botanical Gazette, vol. 74] [264

1922] DUFF—GEOGLOSSACEAE 265

of the ascocarp of Leotia, but, strange to say, he makes no reference
to a veil, although his material apparently included very early
stages of this form. His failure to mention the veil might be due
to the fact that he was chiefly concerned with the origin of the
asci and the nuclear phenomena connected therewith.

From these investigations it will be seen that in two of the
three Helvellinean families, the Geoglossaceae and the Helvellaceae,
an endogenous origin of the hymenium has been claimed. Unti
the publications of FrrzpaTricK (14, 15), nothing was known of
the conditions prevailing among the members of the remaining
family, the Rhizinaceae. FirzPaTRIck has now shown quite con-
clusively that Rhizina undulata, the type of the family, possesses
no investment at any stage of its history, and that, therefore, not
only is the hymenium ‘‘exposed from the first,” but the ascocarp
itself is naked, that is, ‘gymnocarpous.”’

In a preliminary communication the writer (10) briefly outlined
his findings in an examination of four Geoglossaceous forms, namely,
Cudonia lutea, Spathularia velutipes, Trichoglossum hirsutum, and
Leotia lubrica. The veils of Cudonia and Spathularia were found to
be present practically from the first. Trichoglossum proved to be
devoid of all traces of a veil at every stage.. On the other hand,
Leotia lubrica showed some slight traces of a veil, which might be
comparable with the one claimed for it by Drrrricn, but the series
of stages which the writer had under observation did not include
ones sufficiently young to make diagnosis positive, and the question
must still be regarded as an open one.

Turning to the question of the sexuality of the Helvellineae,
there is still less to record. Dzrrrricu found no highly organized
sexual apparatus in either Mitrula or Leotia, and he characterizes
both forms as apogamous. The fertile hyphae here are differen-
tiated from the vegetative threads at an early stage as conspicuous,
deeply staining cells, with large single nuclei.

Similarly McCupstn describes and figures the multinucleate,
fertile elements of Helvella as having their origin in the vegetative
hyphae, from which they spring at a later stage than is the case with
Mitrula and Leotia. No sign of any body resembling an ascogonium
was discovered at any stage.

266 BOTANICAL GAZETTE [NOVEMBER

On the other hand, Brown (4) concludes that Leotia possesses
an ascogonium which makes its appearance early in the history of
the ascocarp. From this the fertile hyphae arise, and may be seen
in succeeding stages, passing upward into the cap, where after much
branching they reach the hymenium and form asci. This asco-
gonium was seen in but one plant, and was observed only in an
empty and partly degenerated condition. The manifestations of
sexuality in Leotia, therefore, cannot be said to have been estab-
lished beyond the possibility of a doubt.

It is only in the work of Firzparrick (15) that we find a wholly
satisfactory description of sexuality in any of the Helvellineae.
This worker has given a very careful and detailed account of sexu-
ality in Rhizina. In this form, while the ascocarp primordia are
yet small, certain multicellular hyphae near the center are trans-
formed into procarps. This transformation entails a great increase
in diameter and in the number of nuclei in the cells, the assumption
of an irregular coiling habit, and the development of a somewhat
elongated terminal cell which may be considered a trichogyne. No
antheridia are present, and the trichogyne is functionless. When
maturity is reached, the centrally situated cells of the procarp
proliferate ascogenous hyphae, and into these the nuclei from all
parts of the procarp migrate, passing from cell to cell through pores
which have previously been formed in the transverse septa. These
nuclei migrate in pairs. Evidence of nuclear fusions in the ascogo-
nial cells or in the ascogenous hyphae is entirely lacking, and neither
conjugate nor simple divisions were observed to occur in the latter.

The conditions obtaining in the species discussed in this paper
have already been summarized (10). It was pointed out that no
evidence of the existence of any type of procarp bodies has been
found in Trichoglossum, in which the ascogenous hyphae arise from
threads of vegetative form adjacent to the hymenium. In Cudonia
and Spathularia the structures interpreted as procarps arise at @
comparatively late stage in the development of the ascocarp from
threads differentiated while the fructification is yet very young:
They are numerous, more or less irregular in form, and while in
Cudonia very distinct trichogynes are organized, similar structures
are absent from Spathularia. In Cudonia the cells of the procarp
appear to be uninucleate at first, later becoming multinucleate,

1922] DUFF—GEOGLOSSACEAE 267

while in Spathularia they are multinucleate from the beginning.
The nuclei in the later stages of these bodies are arranged in pairs.
Ascogenous hyphae take their origin in these procarps, and after
engaging in crozier formation, give rise to asci.

Materials and methods

The material for this investigation was all obtained by collec-
tion, and was variously fixed, the fluids of Flemming and Carnoy,
medium chrom-acetic acid and picro-sublimate, being used. It was
imbedded in paraffin and cut in serial sections 2.5—10 4 thick. The
usual staining methods were employed. Safranin and acid fuchsin
proved to be the best general purpose stains, while Haidenhain’s
haematoxylin gave much the best results where details were
required. In some cases the young fructifications sectioned in
situ were stained by VAUGHAN’s (21) method for the differentiation
of fungous hyphae and host tissues. This method gave very clear
differentiation of the fungous tissue from the substratum, but had
the serious disadvantage of impermanence.

As is not infrequently the case, the cells of certain tissues, while
in a state of rapid growth and development, proved to be exceedingly
difficult to differentiate cytologically, due to the density with which
they are filled with deeply staining substances. As a result it has
been impossible to answer some questions of nuclear behavior as
fully as would be desirable. Otherwise the tissues appeared to be
quite easily amenable to the usual microtechnical methods.

As already indicated, this paper deals in more or less detail
with the four forms Cudonia lutea, Spathularia velutipes, Tricho-
glossum hirsutum, and Leotia lubrica. With the object of emphasiz-
ing the comparative aspects of the investigation, the contents are
arranged in two parts, the first of which deals with the develop-
ment of the ascocarp, with particular reference to the veil, and the
second with the manifestations of sexuality in these plants.

I. Development of ascocarp
CUDONIA LUTEA
The earliest stage of Cudonia lutea of which we have knowledge
is shown in fig. 3. At this stage the ascocarp is very minute, and
measured but 84 from base to apex. It can be seen to consist of

268 BOTANICAL GAZETTE [NOVEMBER

loosely interwoven hyphae, which are obviously mycelial elements
elevated to their present position chiefly by the upward growth of
a central knot of conspicuous, deeply staining threads. The latter
are of peculiar interest on account of the part they play in the
development of the fertile system. At first sight, because of their
marked differentiation from the other threads composing the young
fructification, they might easily be taken for ascogenous hyphae,
or even for ascogonia. At a later stage (fig. 6) the proliferations of
these threads give rise to bodies of characteristic form and history,
bodies that admit of one interpretation only, namely, that they are
procarps. The first appearing threads must therefore have some
significance other than this.

Clearly differentiated bodies are known to originate the procarps
or corresponding bodies in various Ascomycetes. In Ascobolus
carbonarius (DopGE 8) the procarps arise through the germination
of asexual conidia borne on special mycelial branches. BRowN (3)
found that in X ylaria tentaculata the Woronin hyphae are formed
by the continued modification of threads that are differentiated at
the center of the perithecium anlage while the latter is very young
and deeply imbedded in the stroma. According to Miss DAwsoN
(6), a well differentiated thread appears in Poronia punctata, which
at a later stage grows into a procarp.

The nearest approach to the first differentiated hyphae of
Cudonia is to be found, however, in the disco-lichens. NIENBURG
(18) gives a description of the development of the fruit bodies of
four of these lichens, Usnea barbata, Baeomyces roseus, Sphyridium
byssoides, and Icmadophila aeruginosa. It appears from his account
that more or less well developed carpogonia arise in these forms,
not from the ordinary hyphae of the ascomata in which they are
found, but from threads which are differentiated at a considerably
earlier stage. To these threads NreNBuURG applied the name
“Primordialhyphen” or “generativen Hyphen.” In Icmadophila
they appear before the fruit body has begun to rise above the
surface of the thallus.

NIENBURG apparently was not very logical in his use of the terms
““Primordialhyphen”. and “generativen Hyphen.” He employed
the first in his study of Usnea, and the latter in studies of Bae-

1922] DUFF—GEOGLOSSACEAE 269

omyces, Sphyridium, and Icmadophila. He drew no distinction
between the so-called ‘‘Primordialhyphen” of Usnea and the
“generativen Hyphen” of Sphyridium and Icmadophila. In Bae-
omyces, however, the carpogonia are so poorly defined that they
are not separable from the “‘Primordialhyphen,” so to the entire
system in Baeomyces he extended the term “‘generativen Hyphen.”
Then, because of the evidently close natural relationship of Sphyrid-
ium, Icmadophila, and Baeomyces, he adopted the designation
“‘generativen Hyphen” in connection with these forms. It is to
be understood, therefore, that the “generativen Hyphen” of
Baeomyces are not exactly homologous with those of Sphyridium
and Icmadophila.

In the preliminary paper (10) the writer adopted the term
“generative hyphae” rather than ‘“‘primordial hyphae” to desig-
nate the pre-fertile threads of Cudonia and Spathularia. This was
done because the Geoglossaceous forms appear to be more closely
related to Baeomyces, Sphyridium, and Icmadophila than to Usnea.
The occurrence of such a system of threads acting as precursors to
the procarps is unusual, so far as the writer is aware, being found
only in the disco-lichens,. and so may be considered of sufficient
importance to warrant emphasis.

The second developmental stage (fig. 4) shows a very definitely
organized outer tissue, which has apparently been thrown up by
the mycelial threads. By following through the series (figs. 4-7)
this tissue may be seen to be identical with that later regarded as
the veil. The veil in Cudonia, therefore, originates at a time when
the ascocarp is nothing more than a cushion of mycelial threads with
a core of generative hyphae, and can therefore be said to be present
from the first. It is to be noted that at this stage a well marked
clear zone separates the generative threads from the veil tissue.
This clear zone contains only the remnants of the mycelial hyphae
that once surrounded the generative threads. Fig. 5 illustrates
the next developmental stage of Cudonia. Here the generative
hyphae form an elongated mass of filaments of which the oldest are
at the lower, and the newly formed elements, recently proliferated
from them, are at the upper extremity. This upward growth of
the generative threads has completely obliterated at the top the

270 BOTANICAL GAZETTE [NOVEMBER

clear space that once surrounded them on three sides, and at this
point they are now in a subapical position, almost in contact with
the veil tissue. Remnants of the clear space still remain on both
sides, but it is rapidly being filled by the growth of fundamental
tissue which has arisen from the mycelium, and which has pushed up
before it the mass of generative hyphae. The intrusion of funda-
mental tissue from below has its beginning at an earlier stage, and
indications of it may be seen on both sides at the base of the asco-
carp in fig. 4. Judging from these two stages, it would appear
that the most rapid formation of new tissue, at least during the
early stages, takes place at the base rather than at the apex of
the ascocarp.

The subapical position of the generative hyphae is retained as
the ascocarp increases in size, until the apex broadens out to form
the cap. These hyphae then pass into the cap, and there some of
their branches are transformed into procarps. This transformation
entails an increase in diameter, the assumption of an irregular
coiling habit, and the development of a process which passes from
the procarp more or less directly through the veil to the exterior.
These processes are to be regarded as trichogynes. The history of
the procarps will be discussed in greater detail subsequently. While
at this stage, the upper portions of the cap are densely filled with
generative hyphae, procarp complexes, and their proliferations the
ascogenous hyphae, interwoven in an almost inextricable tangle

g. 6

It is important to note that until this time no sign of a hyme-
nium has made its appearance. Very shortly after paraphysis for-
mation commences, however, and following this the ascogenous
hyphae proceed with the proliferation of asci. Paraphyses in
Cudonia arise from undifferentiated vegetative elements. ‘They are
multiseptate, in this respect differing from the description given for
this species by Duran», and their cells are multinucleate. At first
they are straight, but later become strongly recurved at the tips,
which are also somewhat enlarged.

The veil still completely invests the entire ascocarp, including
the hymenium: Over the hymenium it has become separated from
the tissue of the subhymenial region, with, indeed, no attachment
at all except at the edges (fig. 7). Nevertheless it does not cease

1922] DUFF—GEOGLOSSACEAE 271

growth, but persists without rupturing, and keeps pace with the
enlargement of the cap for considerable time. This power of inde-
pendent growth is undoubtedly responsible for the persistence of
the veil in this form, and is expressive of the distinct nature of the
veil as an organ of the ascocarp and of its high degree of organiza-
tion. Dehiscence finally takes place, by which time many of the
asci are matured and their spores ready to be discharged. In the
meantime, with the advent of the paraphyses the trichogynes dis-
appear. The remaining portions of the procarps are visible for
some time after, with cells empty or containing only a few strands
and knots of plasm, evidently in a disorganized condition (figs. 12,
41). Finally practically all traces of them disappear.

SPATHULARIA VELUTIPES

Fig. 14 is a section of the earliest stage of Spathularia velutipes
that has been studied. It can be seen to have been growing upon
much rotted deciduous wood, and to have protruded above the
substratum for somewhat less than 0.5mm. From its size and
organization it is evident that it represents a corresponding stage
considerably older than the earliest Cudonia plants here figured.
The interior of the young fruit body is composed of undifferentiated
fundamental tissue, which is surrounded by a compact and well
defined layer, which, as in Cudonia, is the investing membrane or veil.

By the use of suitable counter stains the veil of Spathularia
velutipes may be sharply differentiated into two layers, an inner
and an outer, the former compact and comparatively thin walled,
and the latter looser and thicker walled. As the ascocarp increases
in size, the outermost layer is split by tension into small adherent
cell masses, which to the naked eye give the fruit body a velvety
appearance. The power of independent growth is just as much a
characteristic of the very persistent veil of Spathularia velutipes as
it is of the membrane of Cudonia. In contrast to the condition of
Cudonia at this stage, however, the interior of the ascocarp is still
undifferentiated, and no threads corresponding to the generative
hyphae of that form are yet visible.

By the time the ascocarp has attained the stage represented in
fig. 15, conspicuous hyphae have made their appearance, and are
situated as the generative hyphae come to be in Cudonia, just

272 BOTANICAL GAZETTE [NOVEMBER

behind the apex. These conspicuous threads in the young Spath-
ularia plant are also generative hyphae, for, as will shortly be seen,
certain of their proliferations at a very much later stage are trans-
formed into procarps. As the young ascocarp increases in size the
pointed apex becomes broadened out, and the generative hyphae
are distributed in an arch below it. This arch widens in concert
with the gradual expansion of the apex into a somewhat globular
cap, which as time goes on assumes the spatular shape character-
istic of the mature plants of the genus (figs. 16, 17).

The expansion of the apex into the cap is marked by the appear-
ance of paraphyses. The paraphyses of Spathularia arise from
vegetative hyphal threads, the end cells of which become somewhat
club-shaped. Various students of other species, as MCCUBBIN (17)
and Brown (4), have found paraphyses arising from specialized
storage cells. This does not occur here, the cells from which the
paraphyses arise being insufficiently differentiated to be regarded as
storage bodies. In form, septation, and nucleation the paraphyses
of Spathularia resemble those of Cudonia.

While the paraphyses are still young, procarps become evident
for the first time. They are scattered about in irregular fashion
through those portions of the cap containing the generative hyphae,
and are complexes conspicuous for their size and staining qualities
(figs. 19-21, 43-45). An examination of all stages after this until
the veil is shed and spores are being cast reveals their presence
continuously. They yary in shape; some appear as coiled struc-
tures, some are immensely swollen, and others take the form of
chains of cells. These bodies arise from the generative hyphae
just as was the case in Cudonia, and from them ascogenous hyphae
proceed directly to the hymenium, where in turn they may be seen
giving rise toasci. Further growth results, as in the case of Cudonia,
in the introduction of no new tissues or organs, but in the mere
expansion of the ascocarp. The hymenium reaches a fairly well
advanced state of maturity before the veil bursts. The observa-
tions of the writer have not established any regularity in the method
of rupture, but Duranp states that “‘the veil seems to rupture by
a crack running around the plant just above the stem,” and exhibits
photographs which illustrate his point.

1922] DUFF—GEOGLOSSACEAE 273

TRICHOGLOSSUM HIRSUTUM

The very young fructification of Trichoglossum hirsutum shown
in fig. 22 measures 175 u in height, and is of simpler structure than
the corresponding stages of either Cudonia or Spathularia. It is
composed of compactly intertwining threads, the walls of which are
comparatively thick and very dark. The hyphae all appear to be
alike except for some, which, situated near the periphery and at
right angles to it, extend beyond the ascocarp as straight, sharp
pointed, unicellular hairs of greater diameter and thicker walls than
the other threads. These setae correspond to similar ones described
by Brown in Lachnea scutellata (5), and by Firzpatrick in Rhizina
undulata (14). The setae of Trichoglossum are differentiated some-
what earlier than in Rhizina, but do not contain a glutinous sub-
stance such as is found in those of the latter form. The setae
in Trichoglossum appear to be continuously produced over all
peripheral parts of the ascocarp as it grows, but those that are
earlier formed persist for some time, and come to be imbedded deeply
in the new tissues that grow up around them. This is particu-
larly evident in the hymenial region, where such growth is rapid
(figs. 25, 26).

Paraphysis formation commences reatively early at the apex
of the ascocarp, before it has begun to broaden out to form the
cap (figs. 24, 25). The paraphyses are large, unbranched, multi-
septate threads, the cells of which are usually uninucleate, but
apparently may come to contain several nuclei in exceptional cases.
They are strongly coiled at the tips.

Shortly after the paraphyses are organized, broadening of the
apex of the ascocarp begins, and the hymenium extends over the
entire surface of the globular cap as it takes shape and expands
into the mature condition.

From the figures it may be seen that the hymenium is of
undoubtedly exogenous origin, and, moreover, the ascocarp itself
is clearly gymnocarpous. Throughout the entire series of stages
careful examination has failed to reveal the presence of an invest-
ment of any kind. Trichoglossum hirsutum, therefore, adds one
more species to those Helvellineae the hymenium of which is exposed
from the first and the fructification gymnocarpous.

274 BOTANICAL GAZETTE [NOVEMBER

The vegetative threads in a well developed ascocarp of Tricho-
glossum hirsutum constitute a loosely interwoven tissue in which
the individual cells of the threads are clearly distinguishable, even
in thick sections. The threads pass with more or less uniformity
from the base to the apex of the ascocarp. Since they are thick
walled and consist of uninucleate cells, it is not difficult to see that
hyphae of any other type are absent. The paraphyses make their
appearance at an early stage (fig. 24), but ascus formation does not
commence until the cap is well shaped. Then, just beneath the
bases of the paraphyses in the subhymenium, there appear thin
walled hyphae which, unlike the vegetative threads, form a very
densely interlaced tissue. These constitute the ascogenous system
of Trichoglossum. It is certain that no bodies such as the generative
hyphae and procarps of Cudonia or Spathularia stand out as specific
organs, nor is it possible to distinguish the homologues of procarps
as distinct from the ascogenous hyphae.

The ascogenous hyphae are short, since they are differentiated
in such close proximity to the hymenium. Asci arise from them
in the usual manner. The formation of an ascus is preceded by
the inversion of the tip of an ascogenous hypha to form a crozier,
the ascus growing out of the penultimate cell. The asci are very
large, with dense protoplasm, and, especially after the dark multi-
septate spores are mature, form very conspicuous objects in the
hymenium (fig. 26).

LEOTIA LUBRICA

Since material of this form had been collected, and since pre-
vious investigators are not in complete agreement on two important
points in the life history, it was thought advisable to examine the
material with a view to the possibility of shedding some further
light on these points. The questions to which reference is made
are those of the presence of the veil and the origin of the ascogenous
hyphae, and attention was confined to these questions alone.

Two specimens at approximately the same well advanced stage
showed irregular tissue fragments overlying parts of the ascocarp
and the hymenium (figs. 27, 28). These specimens were not the
youngest of the fruit bodies examined. In no others, however,
whether younger or older than these, were any similar evidences

1922] DUFF—GEOGLOSSACEAE 275

seen. These fragments are composed of interwoven threads more
or less degenerated in appearance, and in one case still connected
with one another by a few hyphae, which give them the appearance
of having been torn apart by the growth of the ascocarp (fig. 27).
Dirrricn (7) describes the veil of Leotia as having a ground sub-
stance of gelatinous material formed by the progressive inward
swelling (‘‘Verquellung’’) of the peripheral hyphae. In this matrix
are imbedded threads which are rather compactly interwoven.
Apparently, therefore, so far as structure is concerned, the tissue
fragments observed correspond fairly well to the veil tissue of
Leotia as described by Dirrricu. Had very young ascocarps been
available, and had such tissue been found covering them, par-
ticularly as entire structures, DirrricH’s view that Leotia is at
first angiocarpous would have been substantiated. On the other
hand, had the material included a satisfactory series of very young
stages which did not show traces of a veil, the writer would have
felt justified in denying its presence in Leotia lubrica. The youngest
stages available, however, were advanced sufficiently to show a
well differentiated cap and young paraphyses, and consequently
were considerably older than the youngest stages which Brown,
and probably also Dirrricu, had under observation. Under these
circumstances the writer does not feel that the evidence is sufficient
to lend conclusive support to either view. It would seem best,
therefore, to regard the question as still open.

SIGNIFICANCE OF VEIL IN HELVELLINEAE

Ever since the appearance of Dirrricn’s (7) original paper on
this subject, each succeeding investigation has served to emphasize
the inadequacy of the distinction drawn by SCHROETER (20) between
the Helvellineae and the Pezizineae. According to this classifica-
tion, in the former group the hymenium is formed upon the surface
of the ascocarp, and therefore is freely exposed from the first, while
in the latter the hymenium is originally inclosed. ScHROETER’s
fundamental idea appears to have been that in the Pezizas the
hymenium is formed within the ascocarp in an inclosed depression,
while in the Helvellas it appears upon a flat or convex surface, not
closed in.

276 BOTANICAL GAZETTE [NOVEMBER

The discovery of the veil introduces a new morphological feature
not contemplated in SCHROETER’sS scheme. The value of the veil
as an important taxonomic criterion depends, not so much upon
the fact that it may at first inclose the hymenium, as upon its nature
as an organ of the ascocarp. If it were simply the roof of a depres-
sion, comparable with the roof that covers over the young hymenium
of a Peziza, and which breaks away to form the edge of the cup,
then the Helvellinean forms in*which it oceurs would plainly be
only modified Pezizas. But if, as seems to be the case, it were
a distinct envelope which covers over the entire ascocarp, and
perhaps incidentally also the young hymenium, then so far as we
know it is a feature not represented in the Pezizineae, with the
possible exception of the as yet uninvestigated Helotiaceae and
Mollisiaceae.

In reviewing the conditions prevailing in the Helvellineae, it
is found that the veil is absent in the only member of the Rhizi-
naceae which has been studied, it is present in the only member of
the Helvellaceae of which we have knowledge, while at the present
time the Geoglossaceae are about equally divided. In the last
named family the following species may be considered as angiocar-
pous: Mitrula phalloides, Leotia lubrica (Dirrricu 7); Microglossum
viride (DURAND 11); Cudonia lutea, Spathularia velutipes (DURAND
11, Durr 10). The gymnocarpous members appear to be Geo-
glossum glabrum, G. difforme, Trichoglossum velutipes (DURAND 11);
and Trichoglossum hirsutum (McCusBIN 17, Durr 10). It may be
noted that the gymnocarpous species are all closely related, belong-
ing to genera that were at one time comprised in the single genus
Geoglossum, while the others, with the exception of Microglossum
viride, belong to less closely related genera. This means, so far as our
evidence goes, that the Rhizina and Geoglossum groups are typically
gymnocarpous, while the remaining Helvellineae are angiocarpous.

In searching for a structure in other Ascomycetes which might
be homologized with the Helvellinean veil, we find one in the Bae-
omyces group of the disco-lichens. Some such relationship had
already suggested itself to Dirrricu, who, after emphasizing other
points of similarity, goes on to say that in Baeomyces the upper por-
tions of the thallus which overlie the anlage of the fruit body, and
which later surround the young fructification, seem to assume the

1922] DUFF—GEOGLOSSACEAE 277

“functions” of a veil. Although he does not say so explicitly, it
is a fair inference that Dirrricu considered this thalloid invest-
ment of the young Baeomyces fructification and the inclosing mem-
branes of Miirula and of Leotia homologous, for he implicitly
adduces this as evidence of the Geoglossacean affinities of Bae-
omyces. DITTRICH’s conclusions were based upon the description of
the development of the fructification of this lichen given by KRABBE
(16). NurenBuRG (18) re-examined more recently some of the forms
with which KraBBeE worked, and the results recorded in his paper
present even more interesting parallelisms to the conditions prevail-
ing among some of the Geoglossaceae.

In Icmadophila aeruginosa the covering of the ascocarp is more
distinct and more persistent than in Baeomyces. Figs. 1 and 2,
taken from NIENBURG, represent sections of very young fruits of the
former species. Here it may plainly be seen that the superficial
layer of the thallus grows into an envelope for the young ascocarp
and incloses it until it has attained considerable size, after which
the growth of the ascocarp becomes too rapid for the extension of
the epithecial tissue, which then ruptures. The fructification does
not subsequently become covered with any other tissue which might
be compared to a veil, and the hymenium therefore develops exoge-
nously. As has already been indicated, however, the point of impor-
tance in this connection is not the origin of the hymenium, but only
the occurrence of an envelope which incloses the entire ascocarp,
and which constitutes a morphologically distinct organ of the fruit
body. In the opinion of the writer, therefore, the envelopes of
Baeomyces and Icmadophila are strictly comparable and homolo-
gous with those of the Geoglossaceae. From this it follows that in
any natural scheme of classification some lichens, at least those of
the Baeomyces group, must be brought in with the angiocarpous
Geoglossaceous forms, as also possibly some members of the
Helotiaceae.

II. Sexuality
CUDONIA LUTEA

It is in the youngest stages of Cudonia lutea that we find the
beginnings of the hyphal system destined finally to give rise to
asci. As we have seen, here there are differentiated from the

278 BOTANICAL GAZETTE [NOVEMBER

mycelium certain threads which have been called generative hyphae,
and which are the most prominent central components of the simply
organized fructification. These threads are clearly differentiated
in the stained preparation from the rest of the ascocarp. So
vigorously do they react to stains that all details of cell structure
are obscured, even when nuclear stains are applied.

The generative hyphae grow upward as the ascocarp increases
in length, remaining subapically situated. When the upper part
of the fruit body is differentiated into the cap these hyphae make
their way into it, and in that position certain branches of this system
appear that are enlarged, irregularly coiled, and deeply staining
(fig. 6). These are the procarps. The procarp coils are continued
upward by processes which can only be regarded as trichogynes
(figs. 6, 8, 9). These are multiseptate and follow a more or less
direct course toward the exterior. Where the procarps lie in a
suitable position the trichogynes may be followed for their whole
length, and may be seen to penetrate the veil tissue and to reach the
exterior. Sometimes the procarps are deeply imbedded, however,
and in these cases it is impossible to follow the trichogynes as far
as the surface of the ascocarp.

The number of procarps formed in this manner in a single fruit
body appears to be very large, although it is not possible to count
them, on account of the way in which they are interlaced and
because of the presence of masses of generative and ascogenous
hyphae. Some idea of their number may be conveyed, however,
when it is known that as many as seven distinct trichogynes have
been counted in a single longitudinal section 10 u thick through a
region of the cap in which they are numerous. Their distribution
is irregular. Some of them are formed closely under, or even partly
imbedded in the veil tissue, while others are situated at a distance
from the surface in the direction of the center of the cap (figs. 6,
8, 9). Sometimes they are localized in one or two restricted por-
tions of the cap, being entirely absent from others.

Fig. 11 is a portion of an unusually loosely organized procarp.
This section does not contain any of the upper portion of the pro-
carp, but it shows most of the lower part and the generative
hypha from which it arose. The latter follows a somewhat

1922] DUFF—GEOGLOSSACEAE 279

straighter course than is usual with these threads, and hence its
relation to the coil is rendered very obvious. The generative hypha
is more deeply stained than the surrounding vegetative threads,
while the procarp coil itself is quite opaque. Figs. 32-35 represent
other procarp bodies at approximately the same stage of develop-
ment as that of fig. 11. Most of these figures are taken from sec-
tions cut longitudinally through the ascocarp, but fig. 34 represents
portions of a procarp found in two contiguous sections of a series
taken in a transverse plane. These illustrations give some idea
of the diversity of form displayed by these structures. They vary
from an almost straight, slightly twisted series of cells, to coils
such as that of fig. 11. These illustrations also show the relation-
ships of the procarps and trichogynes. This relationship is evident
in fig. 6. Two procarps and their trichogynes appearing in this
section are shown enlarged in fig. 8, where, however, on account of
the thickness of the section and the meandering habit of the threads
of the procarp and trichogynes, not all of these structures can be
obtained in sharp focus at the same time. The protrusion of the
trichogyne from the surface of the ascocarp is shown well in fig. 13,
which is the first section of a series through the cap of an ascocarp
at this stage. The exposed tip of a trichogyne, cut off with the
first section, is clearly shown, several of its cells being visible.

No structures have been found that could be regarded as sper-
mogonia, and no bodies that correspond to spermatia. Furthermore,
the writer has no evidence that the trichogynes functioned in any
way, and since they disappear very soon, is inclined to regard them
as vestigial organs in Cudonia.

As may be seen from the illustrations, the procarps are very
deeply staining bodies, and in their earlier stages it is impossible
to differentiate them cytologically. Nevertheless here and there
an occasional cell may be seen to contain what is doubtless a single
nucleus, while a smaller number contain two (figs. 32-35). Thus what
slight evidence there is points to the original condition of these
bodies as being uninucleate. A little later on, however, they become
multinucleate. This takes place soon after the appearance of the
paraphyses, and is preceded by the disappearance of the tricho-
gynes. At this stage the remaining cells of the procarps become

280 BOTANICAL GAZETTE [NOVEMBER

more distended, and their contents do not stain quite so densely,
and thus cell structures can be distinguished with a greater degree
of certainty. How the originally uninucleate cells become multi-
nucleate is not known. The nuclei are small, and are frequently
on in size. They often appear to lie in pairs (figs. 36, 37, 39,
40

While at the multinucleate stage, or even before they can be
seen definitely to be multinucleate, the procarp cells form branches
which bud out from them (figs. 36, 38, 40). These branches are
ascogenous hyphae, and can. be recognized directly as such from
the fact that in well advanced specimens in which the formation
of asci is just beginning they have been seen passing from procarp
complexes, which are usually empty and degenerated at this stage,
to the hymenium, and there giving rise to asci (fig. 10). Asco-
genous hyphae may be seen passing from an old procarp complex
to the hymenium, which is just being differentiated (fig. 10). In
the subhymenium they are in direct connection with cells under-
going crozier formation preparatory to the formation of asci. The
cells of the ascogenous hyphae are usually multinucleate, but may
be binucleate.

The proliferation of one or more asci from an ascogenous hypha
by the formation of a crozier, with its four nuclei and various evolu-
tions, has been described by numerous workers, and need not be
detailed again. It will be sufficient to say that in Cudonia the
penultimate cell usually grows out into an ascus, but a succession
of croziers may be formed, and there may be a fusion of the ultimate
and the antepenultimate cells, followed by the formation of an ascus
or of another crozier. Several croziers may be formed from a
single cell of an ascogenous hypha, and when all these are confined
to the distal end of the cell a peculiar candelabra-like arrangement
of asci results.

The two nuclei which find their way into the young ascus fuse
at once. The fusion nucleus enlarges as the ascus grows, an
finally assumes very large proportions. Divisions of the nucleus
begin when the ascus has reached about half its ultimate size, and
these divisions succeed one another very rapidly. When eight
daughter nuclei have been formed the spores are delimited.

1922] DUFF—GEOGLOSSACEAE 281

SPATHULARIA VELUTIPES

The origin of the generative hyphae in Spathularia has already
been described. Mention has also been made of the fact that they
come to occupy such a position in the ascocarp that when the
hymenium has been formed they will lie just beneath it. Apart
from their somewhat larger size, conspicuous staining qualities, and
restricted position in the ascocarp, the generative threads do not
appear to differ from the vegetative hyphae. The cells of both
contain from one to several nuclei.

After the paraphyses have been formed, procarps grow out from
some of the cells of the generative hyphae. The procarps are of
relatively large proportions and become ver ¥y str ongl y I i! hil
They are curious conspicuous complexes of hyphae, Attention
has already been called to them, and some of them are illustrated
in figs. 19-21 and 43-45. They appear to exhibit no uniformity of
structure, but their cells are all multinucleate, and frequently dis-
tinct pairing of nuclei is observable (figs. 43-45.)

Ascogenous hyphae arise from these procarps. This is very
easily demonstrated where the hyphal complex lies particularly close
beneath the hymenium, and where the ascogenous hyphae pass
directly into the hymenium. Under these circumstances the ascoge-
nous hyphae take on something of the staining qualities of the cells
from which they arise, and they may be traced with ease into the
hymenium, and there may be seen in connection with asci. Fig. 21
is a plexus of such ascogenous hyphae arising from a group of large
cells, some of which are visible. This large group may be traced
through a series of sections 7.5 u in thickness. The origin and
termination of these threads are not visible in all sections, but by
following through the series their connections in both directions are
easily ascertained.

Fig. 19 affords another illustration of this type, showing two
enlarged procarp cells, somewhat depleted of their contents, one
containing a single nucleus and the other two nuclei. From these
cells deeply staining ascogenous hyphae are to be seen passing out-
ward, following a very irregular course to the hymenium, and there
in direct union with young asci. The group of uninucleate asci of
about the same age shown in this figure appears to have arisen

282 BOTANICAL GAZETTE [NOVEMBER

from ascogenous hyphae originating in the same procarp cells.
More frequently, however, the hyphae passing from the procarps
do not retain their staining qualities sufficiently long to make it
possible to follow them to the hymenium, especially when they are
much branched or when they follow a devious route. The cells of
the ascogenous hyphae are multinucleate, and the nuclei appear to
be paired (fig. 45).

McCussin, who described bodies in the ascoma of Helvella
elastica which bear considerable resemblance to those at present
under discussion, took the view that they are merely storage organs.
In addition to ascogenous hyphae McCussin claims to have found
paraphyses arising from these so-called storage cells. Judging
from his figures, however, the paraphyses arising in this manner are
so far from typical that it may be questioned whether they are
actually paraphyses. Since the ‘‘storage bodies” of Helvella re-
semble the procarps of Spathularia in being multinucleate, in having
the nuclei arranged in pairs, and in producing ascogenous hyphae,
it would seem to the writer that they might also be interpreted as
sex organs. FitzPaTRICK (15) has already expressed this opinion.
He states that “‘several significant facts would seem to indicate that
at least part of these ‘storage bodies’ constitute some type of sexual
apparatus, particularly the statement that they are sometimes found
giving rise to ascogenous hyphae.’”’ The ascogenous hyphae of
Spathularia behave as in the case of Cudonia in the evolution of
asci. The description given for the latter form may be taken to
include them both.

LEOTIA LUBRICA

According to Dirrricn, the fertile threads of Leotia lubrica are
differentiated from vegetative hyphae at an early stage in the history
of the ascocarp. While they do not appear to be easily traced in
intermediate stages, they become conspicuous again as maturity
approaches, this time in the cap, where, lying just beneath the
hymenium, they give rise to asci. Although Drrrricn does not
figure the youngest stage in which they are visible, as he does in
the case of Miirula phalloides, he says that these two forms are
much the same in this regard. If so, the fertile hyphae appear at
a very early stage, indeed, one almost comparable with the youngest
Cudonia plants described in this paper.

1922] DUFF—GEOGLOSSACEAE 283

On the other hand, Brown (4) has figured the remains of what
he interpreted to be an ascogonium, a structure found by him in one
case only, at the base of an older ascocarp than the youngest with
which Dirrricu presumably worked. The ascogenous hyphae pass
up from the ascogonium, and may be traced to the cap, where they
become much branched, finally finding their way to the hymenium.
The writer’s material did not include stages young enough to make
possible a direct confirmation of either of these statements, but it
did show hyphal complexes just previous to the formation of the
first asci strikingly suggestive of those already described for
‘ Spathularia.

At this period the ascogenous hyphae appear under the hyme-
nium as deeply staining threads in various stages of crozier formation
and ascus proliferation, and since they are not numerous as yet, they
are easily distinguished and recognized. Beneath them in the cap
may be seen at the same time very conspicuous groups of greatly
enlarged cells. Some of these enlarged cells are quite empty, some
contain light vacuolated protoplasm, and others are densely filled
with deeply staining contents, identical in appearance with those
of the ascogenous hyphae. These enlarged cells are usually
rounded, occurring singly or in groups, but they may assume any
of a great variety of forms. Their distribution in the ascocarp
follows no regular arrangement whatever. They contain from one
to several nuclei which are variable in size and sometimes may be
very large (figs. 47-53). From these large cells ascogenous hyphae
arise. This is readily demonstrated wherever they occur close to
the hymenial region.

Brown has described what he regards as storage cells in the
ascocarp of Leotia. Of these he says: “While the hymenium is
being differentiated some of the vegetative hyphae give rise to
large storage cells... . . These large storage cells are formed in
rows and give rise to paraphyses. The storage cells are at first
multinucleate, but the nuclei usually fuse as growth proceeds.”
He affirms that the nuclei of these cells, where they are more than
one, may be very unequal in size, and the fusion nuclei are some-
times of extraordinarily irregular form. The writer has not been
able to find storage cells which exactly correspond to those de-
scribed by Brown. The only large unusual cells noted were those

284 BOTANICAL GAZETTE [NOVEMBER

already described, and it is believed that these are BRown’s
“storage cells.”” Careful attention was given to the possibility of
paraphyses arising from these cells, but in the many sections
examined for the purpose of confirming this observation, not a
single clear case of the origin of paraphyses in these bodies was
found.

The fact that ascogenous hyphae arise from these special cells
in Leotia makes it necessary to consider the possibility that they
represent some form of sex apparatus. Obviously, before this
interpretation can actually be put upon them, it will be necessary
to re-examine stages comparable with the youngest which BROWN
studied in order to make sure whether or not an ascogonium occurs
at the base of the young ascocarp. If there be no ascogonium there,
Leotia would then resemble Spathularia in its manifestation of
sexuality.

SEXUALITY IN HELVELLINEAE

The phenomena of sexuality in the Helvellineae bring forward
some interesting questions. In the first place, the large number of
procarps occurring in these Geoglossaceous forms is noteworthy;
the overwhelming majority of Discomycetes possess but a single
one. FirzpATRIck (15) drew attention to this point in his discussion
of Rhizina undulata, which form is characterized by the production
of several of these bodies. This investigator also indicated that
while this character tends to separate the Helvellineae from other
Discomycetes proper, it brings them closer to the disco-lichens,
which are notable for their compound apothecia. F1irzPaTRIcK
quotes a number of lichen forms of which this is true, and to these
may be added those which constitute the subject of NIENBURG’S
(18) researches, namely, Usnea barbata, Baeomyces roseus, Sphyrid-
ium byssoides, and Icmadophila aeruginosa. It may be mentioned
also that in those species in which the procarp is not obviously
greatly reduced, for example in Rhizina undulata and in Cudonia
lutea, it is of the same general form as that which characterizes
lichens, that is, it consists of a modified, more or less coiled multi-
cellular hypha the terminal portion of which constitutes a trichogyne-.
The trichogyne is unicellular in Rhizina and multicellular in
Cudonia.

1922] DUFF—GEOGLOSSACEAE 285

Another feature in common with the lichens is the fact that the
procarps of the Helvellineae are not ‘“‘initial organs’’ arising from
the mycelium and later becoming surrounded by the tissue of the
ascocarp, as they are in Ascobolus, etc., but are formed within an
already well developed ascocarp. This is true of Rhizina, in which
the fructification begins as a ‘wholly undifferentiated button of
mycelium.’’ It is not until the ascocarp has attained a diameter of
about 1mm. that the procarps appear. They then arise by the
differentiation of certain centrally situated hyphae of the fruit
body. In Cudonia the procarps arise at an even later stage, that
is, after the ascocarp has become differentiated into cap and stem,
while those of Spathularia are delayed still further in their appear-
ance.

There is still another point of resemblance between these Geo-
glossaceous fungi and the disco-lichens in their common possession
of a feature noted by Nrenpurc (18), namely, that the procarps
are offshoots of a unique hyphal system (designated by him “‘genera-
tiven Hyphen”’), which makes its appearance at an early stage.
NIENBURG shows that in Icmadophila aeruginosa the ‘ generativen
Hyphen”’ appear as deeply staining threads in the young ascocarp
anlage before it becomes erumpent. As the fructification increases
in size these hyphae proliferate to form scattered knots of threads,
which are connected together, having a common origin, by ‘‘ Verbin-
dungshyphen.” The latter are evidently a part of the system of
“‘generativen Hyphen.’’ These knots become transformed into
procarps, and distinct trichogynes are formed which penetrate the
tissues of the ascocarp and project into the air. Although spermatia
frequently become attached to the trichogynes there is no conclusive
evidence that they are functional, or that a process of fertilization
takes place. Many of the procarps disorganize without producing
ascogenous hyphae, but those that survive act as the source of
these threads.

In Sphyridium the first elements of the pre-fertile system, the
“generativen Hyphen,” appear at a somewhat later stage than in
Icmadophila. In this form they grow into a series of very clearly
defined nests of hyphae, which, as in Icmadophila, are connnected
together by ‘‘Verbindungshyphen.”’ The growth of the vegetative

286 BOTANICAL GAZETTE [NOVEMBER

hyphae carries these knots to the upper portion of the ascocarp
near the surface and separates them from one another. The
ascogenous hyphae arise from these structures. They evidently
represent some form of sex apparatus, but because of their lack of
conventional trichogynes and their irregular habit, NIENBURG
hesitates to give them the full status of typical ‘“‘carpogones.” He
says: “‘Ich glaube deshalb, dasz regelrechte Trichogyne bei Sphyrid-
ium nicht mehr angelegt werden, sondern dasz wir hier reduzierte
Gebilde vor uns haben, die wahrscheinlich friiher als Empfangnisap-
parate gedient, heute aber diese Funktion aufgegeben haben.”’

In Baeomyces the young fructification is sunken in the thallus
and is distinguished as a mass of hyphae more closely interwoven
than those of the thallus. At the center of this mass appear certain
enlarged, deeply staining threads which are the ‘‘generativen
Hyphen,” and which are the source of the ascogenous hyphae.
NIENBURG’S uncertainty in the interpretation of these bodies is
indicated in the following quotations: ‘‘So ist zu vermuten, dasz
auch hier auf sehr friihem Stadium, Askogone als Verzweigungen
der vegetativen Hyphen gebildet werden, die man nur mit unsern
Mitteln von den iibrigen Gewebe—dem askogenen wie dem vegeta-
tiven—nicht deutlich unterscheiden kann. ... . Vielleicht sind die
dunklen Hyphen in den Kniueln der Fig. 17 solche Askogone,
vielleicht sind es aber auch schon askogene Hyphen.” He decides
that they may represent carpogonia, but if so, that they are very
much reduced in Baeomyces, which he regards as an apogamous
form. It is to be noted, however, that ascogenous hyphae still
arise from these bodies even if they are structurally reduced.

These brief reviews indicate how close is the correspondence in
the history of the fertile system between some of the disco-lichens
and of the Geoglossaceae. In both groups the procarps are nu-
merous; they have, in general, the same type of structure; and in
both are formed at a more or less advanced stage from a system of
threads which makes its first appearance while the ascocarp is very
young.

It is interesting that in both groups parallel series are found
showing comparable stages in structural reduction. In the lichens
we have a graded series in Icmadophila, Sphyridium, and Baeomyces.

1922] DUFF—GEOGLOSSACEAE 287

In Icmadophila the procarps are slightly if at all reduced, in Sphyrid-
tum they have lost the trichogyne and become somewhat irregular
in form, while in Baeomyces it is questionable whether such struc-
' tures can be said to occur at all. Among the Geoglossaceae we
have Cudonia illustrating a condition entirely comparable with that
of Icmadophila, while Spathularia resembles Sphyridium in the
much-reduced nature of its procarps. In Trichoglossum the sex
organs do not stand out as morphologically distinct structures.
That these stages in reduction give a picture of the direction of
evolution of sexuality in both groups is the opinion of the writer.
Beginning with a form of procarp in which a true process of ferti-
lization through the medium of the trichogyne took place, the evolu-
tion of these plants seems to have been marked by the successive
suppression of the male organ, the trichogyne, and finally the pro-
carp as a distinctive morphological body.

The facts observed in the Geoglossaceous forms examined point
in a contrary direction to the opinion held by BLackmMaN and
WELSFoRD (1), as stated in their paper on Polystigma rubrum.
They maintain that in all cases where a degenerate ascogonium
occurs, the ascogenous hyphae will probably be found to originate
independently of this organ. Their own recorded observation that

e well organized procarp of Polystigma rubrum takes no part
whatever in the formation of ascogenous hyphae lacks confirma-
tion. Indeed, NIeNBURG (19), in a more recent work on this
species, maintains that ascogenous hyphae do originate in the pro-
carp. Brooks’s (2) similar contention with regard to the part
played by the procarp of Gnomonia erythrostoma, and Fiscu’s (13)
statement on Woronin’s hypha in Xylaria polymorpha, are offset by
H. B. Brown’s (3) observation that the cells of the Woronin hypha
of X. tentaculata actually do become ascogenic.

The parallelism shown to exist between Geoglossaceous and -
disco-lichen forms must surely be significant of phylogenetic
relationship. The question of the relationship of these groups is
of practical interest, in view of the conviction on the part of certain
botanists that the lichen genera should be distributed among those
of the fungi proper. It is recognized by many who favor such a
procedure that the history of the reproductive tracts must ulti-

288 BOTANICAL GAZETTE [NOVEMBER

mately be the basis of any such reclassification. The following
quotation from Frvx (12) exemplifies this view: ‘‘The classifica-
tion of the fungi is really based in the main upon the morphological
relationships of the reproductive areas, and in the lichens also these
relationships surely have a greater importance in classification than
the form-relationships of the thallus.’ This being so, such corre-
spondences as have been disclosed here should indicate a basis of
relationship between the Geoglossaceae and the Baeomyces group of
the disco-lichens. This evidence of relationship is made stronger
by the homology shown to exist between the veils which inclose
the ascocarp in many of these two groups. The further extension
of this relationship should aid materially in the problem of classi-
fication, and should give direction to our ideas concerning the
affinities of these two interesting groups of plants.

Summary

1. The development of the ascocarp in Cudonia lutea and in
Spathularia velutipes is notable for the appearance of an inclosing
membrane which covers over the entire fructification, and whic
constitutes a morphologically distinct organ of the fruit body.
Very early stages of Cudonia show its presence, and it is one of the
first organs of the ascocarp to be differentiated. Trichoglossum
hirsutum lacks entirely any such investment, and the ascocarp is
therefore gymnocarpous. Leotia lubrica shows some evidences of
possessing an evanescent veil, but this is a point which requires
further elucidation.

2. The value of the Helvellinean veil as a systematic criterion
depends more upon the fact that it is a morphologically distinct
organ inclosing the entire ascocarp than that it may result in an
endogenous development of the hymenium. This being so, the
closest homology to the Helvellinean veil is to be found, not in the
Pezizineae, but in the Baeomyces group of the disco-lichens. This is
adduced as evidence of relationship between these groups.

3. The fertile systems of Cudonia lutea and Spathularia velutipes
appear at an early stage in the history of the fructification as
threads which have been called ‘‘generative hyphae.’ These
hyphae proliferate with the other tissues of the ascocarp, and at

1922] DUFF—GEOGLOSSACEAE 289

a later stage give rise to the procarps. The procarps of Cudonia
are irregularly coiled, and are provided with multiseptate tricho-
gynes which pass outward and protrude through the veil. The
nuclear history is not fully known, but the original condition of the
cells of the procarp seems to be uninucleate, later becoming multi-
nucleate, and at this stage giving evidence of nuclear pairing.
Ascogenous hyphae arise from the cells of the procarps, after which
the procarps become emptied of their contents and finally disappear.
The procarps of Spathularia appear somewhat later than in Cudonia,
and are formed close to the hymenium. They are irregular, do
not possess trichogynes, and are obviously reduced in structure.
They are multinucleate throughout their history, and the nuclei
are paired. Ascogenous hyphae arise from them.

4. In Trichoglossum hirsutum there is no structural differentia-
tion of sex organs. The ascogenous hyphae arise from threads
which do not differ in form from vegetative ones.

5. In Leotia lubrica bodies resembling in some respects the
“storage bodies’? described by Brown for the same form were —
found to produce ascogenous hyphae. On this account it is sug-
gested that they may represent sex organs, that is, they may be
degenerate procarps.

6. It is pointed out that there is a very close correspondence in
the history of the fertile systems of the Geoglossaceae and of certain
disco-lichens of the Baeomyces group. This is cited as further
evidence of relationship between them.

7. It is suggested that the progress of evolution in these plants
has been from a type in which fertilization took place through the
agency of the trichogyne, and has been marked by gradual reduc-
tion of the sex organs.

This investigation was conducted under the direction of Pro-
fessor J. H. Fauxy of the University of Toronto, to whom the
writer would acknowledge his great indebtedness for assistance and
criticism through the whole course of the work, and also for liberal
contributions of material.

UNIVERSITY OF TORONTO

290

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BOTANICAL GAZETTE [NOVEMBER

LITERATURE CITED

- BLacKMAN, V. H., and WELSsForD, E. J., The development of perithecium

of Polystigma rubrum DC. Ann. Botany 26:761-767. 1912.

. Brooks, F. T., The eet of Gnomonia erythrostoma Pers. Ann.

Botany 24:58 fe Se

. Brown, H. B., Studies in ihe development of Xylaria. Ann. Myc. 11:1-13.

1913.

. Brown, W. H., The development of the ascocarp of Leotia. Bor. Gaz.

50:443-459. 1910
———., The development of the ascocarp of Lachnea scutellata. Ibid.
52:273-305. IQI1.

- Dawson, Marta, On the biology of Poronia punctata. Ann. Botany

14:245-260. 1900

, DITrTrRIcH, GusTAV, Turk Pee ee ie, | ; es, J , os ee} We: Cohn’s

ore

Beitraige 8:17-52.

- Doncge, B. O., AetiGelai cultures of Ascobolus and Aleuria. Mycologia

42:218-222. 1912.

Snecaremes tf: pein relationships of the F lorideae and the Ascomy-

cetes. ‘Bull. Torr. Bot. Club 41:157-202. 1914.

Durr, G. H. pobatens of the Sais erent Bor. Gaz. 69:341-346.
1920.

Duranp, E. J., The Geoglossaceae of North America. Ann. Myc. 6:
388-477. 1908.

. Fink, Bruce, The nature and classification of lichens. I. Views and

arguments of botanists concerning classification. Mycologia 3:231-269.
IQII.

. Fiscu, C., Beitrige zur Entwickelungsgeschichte einiger Ascomyceten.

Bot. Zeit. 40:865-870, 875-882. 1882.

. Fitzpatrick, H. M., The development of the ascocarp of Rhizina undulata
F

Bot. GAZ. 63: 282-296. 1917.

, Sexuality in Rhizina undulata Fries. Ibid. 63: 201-226. 19
Kpanne, G., Entwickelung, Sprossung, und Theilung oe Hic
pothecien. Bot. Zeit. 40:65-83, 89-99, 105-116, 121-142. I

- McCussin, W. A. Spices sae of the Helvellineae. I. Babes elastica.

Bot. Gaz. 49:195-206. 19

. NIENBURG, W., Beitrige zur Entwickelungsgeschichte einiger Flechtena-

pothecien. Flos 98:1-40. 1908.
. Zur Entwickelungsgeschichte von Polystigma rubrum. Zeit.

6:369-400. 1914

: scan Jy in Higler und Prantl. Die natiirlichen Pflanzenfamilien.

rece R. E., A method for - ogee staining of fun and host
cells. Ann. Mo. Bot. Gard. 1:19

BOTANICAL GAZETTE, LXXIX PLATE VIII

DUFF on GEOGLOSSACEAE

BOTANICAL GAZETTE, LXXIV PLATE IX

DUFF on GEOGLOSSACEAE

BOTANICAL GAZETTE, LXXIV PLATE X

DUFF on GEOGLOSSACEAE

BOTANICAL GAZETTE, LXXIV PLATE XI

DUFF on GEOGLOSSACEAE

BOTANICAL GAZETTE, LXXIV PLATE XIl

DUFF on GEOGLOSSACEAE

1922] DUFF—GEOGLOSSACEAE 291
EXPLANATION OF PLATES VIII-XII
Fics. 1, 2.—Icmadophila aeruginosa: sections of young ascocarps, from
Bape ere fig. 1, X140; fig. 2; X 100
- 3-5; Pediat lutea: suction of young fructifications, showing
generative hyphae and origin of veil; fig. 3, X140; fig. 4, 160; fig. 5, X 140.
Fic. 6.—C. lutea: section of cap of ascocarp, showing procarps and tri-

Pea ie:
Fic. oe . lutea: section of ascocarp, showing veil inclosing young hyme-

nium;

Fics. 8, — —C. lutea: procarps and trichogynes enlarged; 3090.

Fic. 10.—C. lutea: ascogenous hyphae passing from procarp to hymenium;
X 370.

Fic. 11.—C. lutea: lower portion of procarp with generative hyphae;
X 530.

Fic. 12.—C. lutea: old procarp with empty cells; 430.

Fic. 13.—C. lutea: first section of series through cap, showing projecting
trichogyne; 500

Fics. 14-17. oS palbealoss velutipes: sections of young ascocarps; fig. 14,
X50; fig. 15, X35; fig. 16, X35; fig. 17, X40

Fic. 18.—S. velutipes: sections of cap, showing veil inclosing young
hymenium; X150.

Fics. 19-21.—.S. velutipes: procarps and ascogenous hyphae; fig. 10,
X 400; fig. 20, X 250; fig. 21, X310.

Fics. 22-25.—Trichoglossum hirsutum: sections of young ascocarps;
fig. 22, X 100; fig. 23, X80; fig. 24, X33; fig. 25, X27.

ae 26.—T. hirsutum: hymenium; X85.

Fics. 27, 28.—Leotia lubrica: sections of young ascocarps, showing over-
lying aia of tissue; fig. 27, X140; fig. 28, X175

Fic. 29.—L. lubrica: easiest of overlying tissue enlarged; 695.

Fic. 30.—L. lubrica: section of ascocarp, showing enlarged cells resembling
procarps of § pathularia; X70.

Fic. 31.— Cudonia lutea: series of ascocarps at different stages; X3.

Fics. 36-40.—C. Jutea: procarp cells at multinucleate stage; 1125.

Fic. 41.—C. lutea: two ee of procarps with degenerated contents, showing
also generative hypha; X11

Fic. 42.—Spathularia sobs series of ascocarps at different stages; x3.

Fics. 43-45.—S. velutipes: procarp cells; 2000.

Fic. 46.—S. velutipes: old procarp cells with depleted contents; 1125.

Fics. 47-53.—Leotia lubrica: large cells of cap, showing nucleation and
in some cases ascogenous hyphae; X1125.

Fic. 54.—Trichoglossum hirsutum: series of ascocarps at different stages;

A MORPHOLOGICAL STUDY OF THE UMBELLIFERAE
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 298
HILARY STANISLAUS JURICA
(WITH PLATES XIII, XIV)

Introduction

The fact that the Umbelliferae are so extensive and so well dis-
tributed throughout the northern university zone has made them
an object of frequent study. CESALPIN (9) was the first to assemble
the different members of the Umbelliferae into a separate group,
not only on the basis of their umbellate inflorescence, but also on
the basis of a secondary character, the two-celled ovary, each cell
of which gives rise to a single seed. Morison (51) recognized the
family on the basis of the same characters as CESALPIN, but added
a number of other plants, especially some of the Valerianaceae and
Thalictrum, which of course, were not destined to remain within
this family. To these, he applied the name of imperfect Umbel-
liferae. According to GENEAU DE LAMARLIERE (27), however, it
was left for HERMANN (1690) to establish a rational division for
this family, namely, (1) species with ovate seeds; (2) species with
hairy or spiny fruits; and (3) species with large and flattened
fruits. Following HerMANN, MAGNoL (27), in 1709, divided the
family into four groups based on the character of the surface of the

(r) fruit ribbed, (2) fruit large, (3) fruit spiny, and (4)
fruit long.

The classification of the Umbelliferae entered upon a new phase
with LinnE (45), who selected or rather borrowed from his contem-
porary ARTHEDIUs the row of bracts of the involucre and of the
involucel as a principal character, upon which he based his division
of the Umbelliferae, with the already mentioned external features
of the fruit as secondary characters. At this time the essential
distinction between a cyme and an umbel was not considered, and
accordingly very many forms were included, which later workers,
notably ADAMSON (1), CRANTZ (15), SPRENGEL (63), HOFFMANN
Botanical Gazette, vol. 74] [292

1922] JURICA—UMBELLIFERAE 293

(32, 33), Kocu (42), Dr CaNpotte (17), etc., assigned to other
families. A somewhat extensive discussion of the history of the
classification of Umbelliferae may be found in the work of GENEAU
DE LAMARLIERE (27). For American workers, COULTER and RosE
(13) listed a condensed bibliography of all the works containing
new names or new descriptions of Umbelliferae found within the
North American range, from LinnaEvs’ Species Plantarum (1753)
to that of ConGDON (1900).

The first morphological work of note upon the Umbelliferae
was that of TrrrmaNnn (65), whose figures showed the germination
of some species with great exactness. Influenced by the research
work of their age, or at times by the somewhat peculiar nature of
the plant at hand, a further study of the germination of a large
number of genera and species was made by DE CANDOLLE (17),
TREVIRANUS (69, 71), BERNHARDI (4), KIRSCHLEGER (40), IRmIscH
(36, 37), VAN TrEGHEM (76), GENEAU DE LAMARLIERE (24, 25, 26,
27), Domin (18), DRrupE (20), Hoim (35), and Mésrus (49).

Although Dr Canpo.te (16) had already described the stem of
Ferula, whose medullary bundles could easily lead one to mistake it
for amonocotyledon stem, it was left for HoFFMANN (34) to present us
with the first extensive anatomical work upon the Umbelliferae.
His study of the roots of the plants of this family contains many
interesting details, but it is to be regretted that he failed to dis-
tinguish the root from the rhizome, and at times even confounded
it with the lower part of the aerial stem. Moreover, he paid no
attention to order and very little to development.

Further anatomical studies were made by JocHMANN (38),
REICHARDT (58), DUCHARTRE (21), BEHUNECK (3) FAURE (22),
GERARD (28), TREcUL (68), CourcHET (14), Hotm (35), KLauscH
(41), GENEAU DE LAMARLIERE (27), NOENEN (55), and NESTEL (54).
The work of Mésrus (49), however, deserves special attention,
for the parallel-veined leaves of numbers of species of Eryngium,
together with the general aspect of their gross morphology, lead
many taxonomists to suspect an analogy in their anatomy to that
of some of the monocotyledons. Accordingly, we have species like
Eryngium yuccifolium Michx., E. bromeliaefolium Delar., E.
pandanifolium Chan., E. lusulaefolium Chan., E. junceum Chan.,

294 BOTANICAL GAZETTE [NOVEMBER

and E. scirpinium Chan. In his extensive work covering the
anatomy of the leaf, stem, rhizome, and root, M6sius showed that
this similarity is only apparent, and that in reality the stem of
Eryngium is not merely a dicotyledon, but is one of an advanced
type.

A rather unique and quite extensive study of the mechanical
tissue in the stem and leaf was made by FuNK (23), as recently as
IQI2.

The formation of the leaves, umbels, and gross morphology
next received attention from workers like JocHMANN (38),
BUCHENAU (7), Mout (50), ROSSMANN (60), CLos (10, 11), GERARD
(28), Ktauscu (41), Domin (18, 19), PETERSEN (57), RENNERT (59),
TERNETz (66), WRETSCHKO (84), and GRIESEBACH (209).

The oil ducts or secreting canals were studied by MEYEN (47),
JocHMANN (38), MEYER (48), VAN TIEGHEM (73, 74, 75), MULLER
(53), MoyNIER DE VILLEPOIX (52), LANGE (43), and VUILLEMIN (79).

PAYER (56), TRECUL (67), and JocHMANN (38), whose works
appeared but a few months apart, were the first to attempt-the
organogeny of this family. In the formation and development of
the leaves all three disagree, and all differ from the account given by
GRIESEBACH (29), but the accounts of PAYER (56) and JoCHMANN
(38) agree in regard to the floral development and also with the
accounts of SIELER (62) and HANNAH (31). SIELER, however,
interprets the “calycis primordium” of these workers as a special
kind of organ, which gives rise to the calyx, and naturally he finds
fault with the seemingly existing ‘“primordialkelch,”’ a view which
I failed to receive from the reading of both Paver’s and JOCHMANN’S
works. JOCHMANN’S work especially evinces great care, and no
doubt, had modern technique been available in his day, the embry-
ogeny would have been included. Like all the earlier workers,
JocHMANN begins his study with germination, but, unlike them,
he pays special attention to the root, rhizome, and stem, their
anatomy, and their oil ducts. He then proceeds to discuss the
development of the leaves, umbels, flower, stylopodium, style,
“‘gynoecium,”’ pericarp, and the seed.

Among other workers dealing with the development or histology
of the fruit may be mentioned Lanessan (44), BartscH (2);

1922] JURICA—UMBELLIFERAE 295

TREVIRANUS (70), and TANFANI (64). Quite recently an approach
was made to the study of embryogeny by CAMMERLOHER (8), who
studied the “Samenanlagen”’ of a large number of genera; and
MarTEL (46) presented us with an anatomy of the flower.

Summing up all the work done, however, we find that the
Classification, gross morphology, anatomy, mechanical tissue, oil
ducts, development of leaves and inflorescences, floral development,
and development of fruit in this family are well covered, but
embryogeny proper, endosperm formation, and the embryo still
remain to be studied. It is with a view to filling this gap that this
investigation has been entered upon.

Methods

The material used in this study was collected at different
intervals in the vicinity of Lisle, Illinois. The fresh material was
killed in a stock solution of chromo-acetic acid, imbedded in paraffin,
and stained usually with either safranin and Delafield’s haemo-
toxylin, or safranin, gentian violet, and orange G (omitted in a
few cases).

The study centers about Eryngium yuccifolium, with frequent
comparisons with other genera, especially Sium cicutaefolium.

Floral development

No attempt has been made to present a study of the development
of the inflorescence or umbel, for that has already been well studied
by workers listed in the introduction. Nevertheless, since the
umbels of Eryngium yuccifolium consists of distinct compact
heads, a short note in regard to the head will not be out of place.

The central or apical head of each umbel develops earlier and
more rapidly than the encircling members, hence by the time the
central head becomes visible to the naked eye, longitudinal sections
show that the encircling heads develop in the axils of the bracts
subtending the umbel, in much the same manner as described by
Jurica (39) for the heads of Dipsacus sylvestris (fig. 1).

As already has been described by JOCHMANN (38) for Eryngium
planum, all the flowers in the heads of Eryngium yuccifolium arise
from the axils of bracts spirally arranged. The blossoming begins

296 BOTANICAL GAZETTE [NOVEMBER

at the base and extends toward the apex (fig. 1). The individual
epigynous flowers appear as an undifferentiated mass of cells,
somewhat rounded at first (fig. 2), but soon broaden out, so that
the individual sepal primordia forming the calyx (which is well
pronounced in Eryngium yuccifolium) are distinctly visible (figs.
3, 4). This is soon followed by a perfect and regular acropetal
succession, presenting the sequence sepals, petals, stamens, and
carpels, in perfect accord with the account given by HANNAH (31)
for Sanicula marilandica; by PAYER (56) for Heracleum Sphondylium
(and other species of Heracleum), Carum, Aegopodium, Anethum,
Phellandrium aquaticum, etc.; and by SIELER (62) for Heracleum,
Sphondylium, Chaerophyllum bulbosum, Cicuta virosa, Daucus Carota,
Peucedanum cervaria Lat., Angelica sylvestris, etc. (figs. 2-7). Itis
well to note, however, that SEILER (62) is more concerned with the
study of the sequence of the appearance of individual members
within a cycle than with the sequence of the cycles themselves.

JocHMANN (38) had noted that, although the calyx primordia
make their regular appearance in Aegopodium, etc., they fail to
continue in their development (“‘in pristino statu remanent, et quo,
magis flos accrescit, eo magis evanescunt’’), and thus apparently
simply remain as calyx teeth, and in many genera even these are
obsolete and hardly distinguishable (figs. 9, 10).

Ovules

The carpels are distinctly two in number at first, but soon
unite along their inner face, so that in cross-section they appear to
be semicircular (fig. 7); or as PAYER (56), JOCHMANN (38), SEILER
(62), and CAMMERLOHER (8) would have it in the forms studied
by them, “semilunar” in shape. In each of the four free ends of
the coalesced carpels an anatropous ovule begins to develop (figs.
11, 12), one of which soon stops, however, while the other continues
in its normal development. This results in a hanging anatropous
ovule, with the raphe turned inward and the micropyle outward
(fig. 14). This seems to be quite general for the entire family, for
it has been found in all the species studied, and it is in accord with
the account of CAMMERLOHER (8), who studied the “Samenanlagen”
in thirty-seven genera and forty-five species. Moreover, JOCHMANN

1923] JURICA—UMBELLIFERAE 297

(38), Paver (56), and SEILER (62) have noted it in their work.
Nevertheless, it is not out of place to note that, in one exceptional
case, all the flowers of one head of Eryngium yuccifolium developed
two normal ovules in each ovary cavity (fig. 13).

Megaspore and embryo sac

By the time the ovule has reached the stage shown in fig. 17,
the nucellus has become quite prominent, and the hypodermal
archesporium is easily recognizable (fig. 18). This figure shows the
megaspore mother cell nucleus in synapsis, which indicates that
the reduction division is about to occur. The successive stages
in the development of the megaspore, resulting in a linear row of
four megaspores (fig. 19), as well as the destruction of the potential
Mmegaspores, present no essential deviations from the process as
ordinarily described, for the embryo sac develops from the innermost
megaspore, and Sium cicuiaefolium is no exception in this case
(figs. 15,16). The nucellus has only a single layer of cells surround-
ing the megaspore, but the absence of tapetal cells is well com-
pensated by the presence of a nutritive apparatus (figs. 16, 20-25)
in the chalazal region. The nucellus undergoes but slight develop-
ment, and then begins to break down (figs. 16, 21-25). Even in
the development of the embryo sac there is nothing unusual.
The megaspore nucleus divides by three successive divisions, and
at first an eight-nucleate, and then a seven-nucleate embryo sac
is the result. The amount of protoplasm in the developing sac
is comparatively small, frequently resulting in the presence of very
large vacuoles, not only in the embryo sac proper, but in the
synergids and oosphere as well (figs. 23-25). The antipodal cells,
three in number, can easily be seen in the embryo sac before the polar
nuclei fuse, and generally are arranged in the form of a triangle
(fig. 24). They soon break down, however, and only rarely can
be distinguished at a later stage (fig. 16), that is, they are somewhat
ephemeral, breaking down shortly before or after the fusion of the
polar nuclei.

Endosperm and embryo

Shortly after double fertilization the endosperm nucleus begins

to divide, forming an endosperm consisting of free nuclei (figs. 26,

298 BOTANICAL GAZETTE [NOVEMBER

27). The early divisions of the endosperm nuclei occur more
rapidly than those of the embryo, and very soon cell walls make
their appearance. Even after the formation of cell walls, the
endosperm continues to form so rapidly that when the seed is
mature the small, insignificant, yet massive embryo (figs. 28-30)
is practically inclosed in rich endosperm tissue. In its development
the embryo does not always divide into regular octants (figs. 28-30),
but at times is quite irregular. Very frequently in its early develop-
ment it looks more like a pteridophyte embryo (fig. 28), and is
characterized by a long suspensor.

Relationships

The Umbelliferae are very closely related to the Araliaceae
and Cornaceae, with which families they form an alliance or order
known as the Umbellales, or the ‘‘Umbelliflorae” of ENGLER.
Although several workers, notably HALLIER (30), WETTSTEIN (83),
and WERNHAM (82), have elaborated various tables showing the
probable phylogenetic relationships, the scheme of ENGLER is still
followed by most workers. In ENGLER’s classification the dicoty-
ledons are divided into two great divisions, the Archichlamydeae
and Sympetalae, which, according to COULTER and CHAMBERLAIN
(12), however, show no sharp distinction, for ‘“‘sympetalous forms
occur among the former, and polypetalous forms among the latter.”
The distinction is laid principally upon a single character, namely,
apetaly or polypetaly for the Archichlamydeae, and sympetaly for
the Sympetalae. Without doubt this is pressing a single character
too far, and as a result the Umbellales “‘stand so stiffly apart from
other Archichlamydeae as to raise the question whether they do
not really belong among the higher Sympetalae”’ (12).

It will not be out of place to indicate such evidence as there is
for such an assumption from the taxonomists’ point of view. For
this purpose the recent extensive work of VIGUIER (78) may be cited.
In his chapter dealing with the relationship of the Araliaceae with
other families, he definitely proves the close relationship of the three
families forming the order Umbellales, claiming, for example, that
the only character which separates the Araliaceae from the Umbel-
liferae is the drupaceous fruit of the former, whereas the two

1922] JURICA—UMBELLIFERAE 299

families have a number of general characters in common. He also
states that not a single anatomical character permits an absolute
separation of the two families. After describing the details of this
anatomical relationship, he concludes that the Umbelliferae, with
the Araliaceae, form a continued morphological series and a very
natural group. VIGUIER next shows that the Cornaceae are closely
related to the Araliaceae, claiming that even good systematists at
times take a single genus out of one of the families and put it
into another. WANGERIN (80) and WARMING (81), however, would
separate the Cornaceae from the Umbellales on account of the
nature of the ovule. No less apparently conclusive is the account
of WETTSTEIN (83) in regard to the inter-relationship of the three
families forming the Umbellales.

With this inter-relationship established, we can safely return
to VIGUIER (78), who compares the Pittosporaceae with the Umbel-
liferae and Araliaceae on the basis of the presence of secreting canals,
for which reason VAN TreGHEM (77) has added this as a fourth
family of the order Umbellales, and his studies upon the ovule of
the Pittosporaceae confirm his view.

This interpretation seems plausible, for the ovary of the
Pittosporaceae is likewise bicarpellate, although the ovules them-
selves are free and generally parietally arranged in two rows.
The single integument, and the fact, as WETTSTEIN (83) has it,
that the corolla is very often somewhat sympetalous (“‘Korolle
manchmal etwas sympetal”), prove that at any rate the Pitto-
sporaceae are out of place among the Rosales, and no doubt belong
among the Sympetalae. The inclusion of the Pittosporaceae in
the Umbellales by VAN TrecHemM likewise demands the transfer
of the entire Umbellales to the sympetalous dicotyledons. Accord-
ingly they are not to be viewed as an order closing up the Archi-
chlamydeae line, the next of kin to the Myrtales. This is in spite
of the fact that the Umbellales have some characters in common
with some of the Myrtales, especially with Hippurus of the
Haloragidaceae, such as epigyny, single integument, etc., for they
stand too sharply apart from the rest. The position of families
forming the order Myrtales certainly deserves a reconsideration,
and this has already been done in part by SCHINDLER (61), who

300 BOTANICAL GAZETTE [NOVEMBER

separated Hippurus from the Haloragidaceae on the basis of its
morphological characters, and made a new family entitled Hippuri-
daceae. Further rearrangement no doubt will follow later, when
more morphological work has been done on the group.

Viewing the Umbelliferae from a morphological standpoint,
it is clear that separate petals are the only character which they
have in common with the Archichlamydeae, and they even lack
sympetaly, if the Umbellales are taken as a whole on the basis of
VAN TIEGHEM’S work on the Pittosporaceae; for, according to
BESSEY (5), ‘one organ.may be advancing while another is retro-
grading.”

“The complete cyclic arrangement of floral members associated
with definite numbers” (12), the single integument (fig. 17), the
anatropous ovule (fig. 14), the absence of parietal tissue of the
megasporangium (fig. 18), the small nucellus (fig. 18), and the
complete tetrad of the megaspores (fig. 19) of the Umbelliferae,
all of which are general characters of Sympetalae in contrast with
those of the Archichlamydeae, from which the Umbelliferae stand
so stiffly apart, prove that the Umbellales in reality belong among
the Sympetalae.

The question now arises, if they are to be placed among the
Sympetalae, what is their relative position? This is not difficult to
answer, for the epigynous nature of their flower places them surely
above the Tubiflorales, and their other floral characters put them
below the Campanulales. Hence, a position in the neighborhood
of the Rubiales is without question. C. E. Brssry (5), E. A.
BEssEY (6), and WETTSTEIN (84) consider the Umbellales as giving
rise to the Rubiales. WerrnuaAm (82) notes that “within both
cohorts,”’ as he calls them, “the progress from polycarpellary to 4
bicarpellary gynoecium is observable; in both the ovary is only
very rarely unilocular; and in both the androecium is primitively
isomerous with the corolla, and the latter primitively regular.”
Accordingly, he recognizes the ‘‘ Umbelliflorae as the representatives
of a side branch from the calycifloral (rosalium) plexus, and the —
Rubiales as another such side branch of this stock.” All this is
to fit in with his scheme of a polyphyletic origin of the Sympetalae.

1922] JURICA—UMBELLIFERAE 301

On the other hand, Hatter (30) would have a common
“Umbellifloren” stock reaching from the Terebinthaceae, and giving
rise to Cornaceae, and through these to two branches, namely, to
Umbelliferae on one side and to Rubiales on the other. From this
it is evident that, although these systematists disagree as to details,
they agree upon the fact that the Umbellales are related to Rubiales.
Recognizing ENGLER’s scheme of classification as the one more
commonly and more widely accepted, and in view of the numerous
facts, both from the taxonomic and morphological field, I suggest
that the Umbellales be placed among the Sympetalae parallel with
the Rubiales. Even if the viewpoint of WANGERIN (80) and
WarMiInG (81) in regard to the Cornaceae should be proved to be
correct and universally accepted, this would not affect the remaining
families of the Umbellales, for then the Cornaceae would be trans-
ferred to a position in close association with the Caprifoliaceae.

Summary

1. The floral development shows an acropetal succession of
floral cycles, namely, sepals, petals, stamens, and carpels.

2. In the genera in which the sepals are represented by mere
calyx teeth or are obsolete, the calyx primordia also make their
appearance, but fail to develop any further.

3. The carpels are two in number and later fuse to form the
ovary.

4. Two anatropous ovules begin to Geysop 3 in each cavity, but
usually the lower one reaches maturity.

5. The hanging anatropous ovule has a single integument.

6. The nucellus is very small, and the hypodermal archesporial
cell is easily recognizable.

7. The megaspore mother cell produces a perfect linear tetrad,
as a result of two successive divisions.

8. The embryo sac develops from the innermost megaspore,
the three others aborting.

9. A regular eight-nucleate and subsequent seven-nucleate
embryo sac results from three successive divisions of the megaspore,
followed 2 the fusion of the polar nuclei.

302 BOTANICAL GAZETTE [NOVEMBER

10. The antipodals are somewhat ephemeral, breaking down
either shortly before or after the fusion of the polar nuclei.

11. The endosperm nucleus is the first to divide after double
fertilization, and for a while continues to produce free nuclei, but
cell walls soon appear.

12. The fertilized egg is slow to divide, and undergoes no
extensive development, so that the ripe seed has a small embryo
imbedded in rich endosperm tissue.

13. The suspensor is somewhat long.

14. The morphological features of the Umbelliferae show that
they are out of place among the Archichlamydeae, and that they
belong among the Sympetalae, in spite of their separate petals,
just as Agapanthus is a good monocotyledon in spite of its two
cotyledons.

15. The epigynous nature of the flower in close affinity with that
of the Rubiales warrants the placing of the Umbellales about
parallel with the Rubiales, among the Sympetalae, that is, as a
side line having a common origin with the Rubiales.

Acknowledgment is due to Dr. CHARLES J. CHAMBERLAIN for
proposing the problem, as also for suggestions during the course of
the investigation.

St. Procoprus CoLLEGE
Liste, Int.

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7:
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Nova Acta Acad. Carol. Leop. XII.

Lance, Jutius, Uber Entwickelung . "Gulbebitiog in den Friichten der
Umbelliferen. Diss. Koenigsberg. 18

LE Langssan, J. L., peibeaio eT sur i developpement du fruit des
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1922] JURICA—UMBELLIFERAE 305

51. Morison, RoBERT, Plantarum Umbelliferarum distributio nova. Oxonii.
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52. MOvyNIER DE VILLEPOIX, R., Recherches sur les canaux sécréteurs du fruit
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54. NESTEL, A., Beitrage zur Stengel und Blatt econ der Umbelliferen.
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306 BOTANICAL GAZETTE [NOVEMBER

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EXPLANATION OF PLATES XIII, XIV

Abbreviations: fh, floral head;eib, involucral bract; fb, floral bract;
fp, floral papilla; s, sepal; p, petal; st, stamen; c, carpel; ct, calyx tooth;
o, ovule; es, embryo sac; mm, megaspore mother cell; m, megaspore;
rn, reciatos of nucellus; na, nutritive apparatus; pn, polar nucleus; a, antipo-

; ra, remains of satinodsla: fn, fusion nucleus; e, egg; syn, synergids.

Fic. 1.—A central head of Eryngium yuccifolium, showing origin of ‘ators
heads composing umbel.

Fics. 2-7.—Stages in floral development of E. yuccifolium.

Fic. 8.—Single mature flower of E. yuccifolium in cross-section, showing
Bie OS of floral cycles.

Fics 10. Be ings in floral development of Zizia aurea, especially
showing cee teet

PLATE XIII

BOTANICAL GAZETTE, LXXIV

J WN
oo

JURICA on UMBELLIFERAE

PLATE XIV

BOTANICAL GAZETTE, IXXIV .

JURICA on UMBELLIFERAE

1922] ; JURICA—UMBELLIFERAE 307

Fic. 11.—Longitudinal section of ovary of Sium cicutaefolium, showing
the two ou beginning development in one of ovary cavities.
Fic. 12.—Section of E. yuccifolium ovary, showing the two ovules in
single ovary cavity; only lower ovule generally develops.
1G. 13.—Longitudinal section of ovary of E. yuccifolium, showing an
unusual condition, the developing of two ovules in single ovary cavity.
FI ves —Anatropous ovule of E. yuccifolium
Fic. 15.—Nucellus of Sium seeagec iouing two cells, result of
first division of megaspore mother c
Fic. 16.—Mature embryo sac of S. cicutaefolium, showing breaking down
of sinaling. egg, one of synergids, fusion nucleus, three antipodals, and nutritive
apparatus.
Fics. 17-30.—Eryngium yuccifolium.
Fic. 17.—Ovule showing single integument and nucellus.
Fic. 18.—Nucellus showing megaspore mother cell in synapsis.
Fic. 19.—Nucellus showing four megaspores
Fic. 20.—Single megaspore from which entre sac will develop; nucellus
beginning to break down.
Fic. 21.—Two-nucleate embryo sac, showing nutritive apparatus.
Fics. 22, 23.—Two and four-nucleate embryo sac, showing nuclear
divisions.
Fic. 24.—Lower end of embryo sac, showing one of polar nuclei, three
stip, and nutritive apparatus.
G. 25.—Mature embryo sac, showing remains of broken down nucellus,
egg, re ie fusion nucleus, remains of antipodals, and nutritive apparatus.
Fic. 26.—Embryo sac in cross-section, showing endosperm formation b
free nuclei.
Fic. 27.—Free nuclei of endosperm of embryo sac in longitudinal section.
Fics. 28-30.—Embryo and suspensor.

DETERMINATION OF MOISTURE CONTENT OF
EXPRESSED PLANT TISSUE FLUIDS’
Ross AIKEN GORTNER AND WALTER F, HOFFMAN

The fact that the physico-chemical properties of plant tissue
fluids reflect in many instances the ecological environment of the
plant, and that the ability of a plant to exist under widely different
environmental conditions appears to depend largely upon its ability
to adjust the physico-chemical properties of its tissue fluids to the
new environment has only recently been recognized. Harris (3)
has pointed out that any thorough ecological study should include
physico-chemical studies of the plant saps. GORTNER and HARRIS
(1) have indicated some of the precautions which must be taken
in order to secure an accurate measure of the osmotic pressure of
expressed plant saps by the cryoscopic method, and in subsequent
papers Harris and his co-workers (4, 5, 8-14) have investigated the
physico-chemical properties of plant saps in a variety of habitats.
The physico-chemical determinations which have been used have
necessarily been limited to those which are adapted to field labora-
tory facilities, and which do not require excessive amounts of either
time, apparatus, or plant materials. The determinations have
therefore been confined exclusively to the measurement of osmotic
pressure by the cryoscopic method, the electrical conductivity by
the conventional wheatstone bridge, and more recently hydrogen
ion concentration (unpublished data).

Throughout all this work it has been recognized that a knowl-
edge of the moisture content of the expressed plant saps would be
most desirable. For example, a knowledge of the total solids com-
bined with the depression of the freezing point would permit the
calculation of the “average molecular weight” of the dissolved
solutes. An increase in “average molecular weight” in a different
environment might logically be interpreted as indicating a response

‘Contribution from the Division of Agricultural Biochemistry, University of

Minnesota; published with the approval of the Director as Paper no. 322, Journal
Series, Minnesota Agricultural Experiment Station.

Botanical Gazette, vol. 74] [308

1922] GORTNER & HOFFMAN—MOISTURE CONTENT 309

to the changed environment by the elaboration of more colloidal
materials. In some of the earlier papers (2, 6, 7) it was possible to
secure these data by the rather laborious procedure of drying
weighed portions of the saps in a water oven at 100° and weighing
the residue. This method, of course, is wholly unsuited to field
studies where hundreds of samples are involved, and is likewise
inaccurate, inasmuch as caramelization of the sugars always takes
place when plant saps are dried by means of heat. Marked caramel-
ization can only be prevented by drying at room temperature in
vacuo over sulphuric acid, or by drying in a vacuum oven at not to
exceed 50°C. When such methods are employed constant weight
is not reached until several days have elapsed.

Another objection to any drying process for field laboratory
work lies in the fact that there may be suspended cell débris in
expressed plant sap. With abundant laboratory facilities at hand
it is comparatively easy to remove such materials by means of a
high speed centrifuge or rapid filtration, but in a field laboratory
not equipped with a powerful centrifuge, the removal of such débris
may be so incomplete as to seriously affect values of dry matter
determinations obtained by a drying process.

It recently occurred to one of the writers that it might be possible
to determine the moisture content by making use of the refractive
index of the plant sap. This method has been employed by sugar
manufacturers for many years, and refractometers may be purchased
which have a special “‘sugar scale” from which the percentage of a
sugar in a syrup may be read directly.

Tables of refractive indices were consulted and they confirmed
this theory, for the refractive indices of solutions of inorganic salts
and proteins in the concentrations normally present in plant saps
appeared to be sufficiently near the values for solutions of carbo-
hydrates so that no excessive errors should result. Accordingly a
high grade Abbé refractometer was secured, provided with a special
sugar scale, and carefully standardized by the Bureau of Standards,
and determinations were made on a series of plant saps with the
resultseshown in table I. This table does not represent selected
determinations, but instead every determination which was com-
pleted is included, with the exception of two or three where accidents

[NOVEMBER

BOTANICAL GAZETTE

310

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See BO) Baar Dew shen ia oe 98 “96 Sg ‘ 36 * anes gree T 5 ‘ oo ee rodng ‘IBA arena won, “Iz
or ie £6°10 of 06 $gorr PLYE 1 ee ‘**gadng “IBA ore3|NA UMIU, ‘oz
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obz 10'S6 P ‘ ob +6 oI “+6 +lv'‘o PIP? I tS 1 388s 2S Cao ak es eee umurdAyeo wm AydoArg “Sr
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OF 1S Satie se S$-S6 61°S6 o$ ‘+6 gS6'0 Se eee See ee ee eee vIOTUII}]2 sniadi7 9
SSr Pa ee es ae zr 96 ££°96 006 olf‘o Sie ee ee eee 8 ae a 8 eee ee ew Aa ee kee Binpuad eBUuLIqeZ “¢
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ofz g6 So ie ec McC or'b6 gos ee SIRE rt ee ee eee wmuqoAyeo wm Aydosrg "S
Oz Cele) ‘o6 WE See ee ee eS eee ia Mae Pee forom 88 Cie eb te ta et et 8 8 4 ie ee win ee es sisuopeuro snonqures *Z
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ag ap : gf oy : prec gg et apnea (a8vyueos0d) +) 08 XOput
Iepndajout ,OOI 38 a1our | ,oor 78 a10Ur — ‘onopa gra pemnen v dATIVIJIY jo SdAva]T
asvIoAy sinoy 9 palip smoy ZIpeup| ue '*osty q 2INjSIOYy
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I ATavL

1922] GORTNER & HOFFMAN—MOISTURE CONTENT 3I1

happened to the duplicate set being dried either over sulphuric
acid or in the vacuum oven.

The tissue fluids were obtained by means of a specially con-
structed press bowl, and a hydraulic press, after the tissue had been
rendered permeable by a preliminary freezing of the tissue for at
least eight hours, following the procedure recommended by GoRTNER
and Harris (1) and used in all of the previous work. All saps were
centrifuged perfectly clear from suspended débris. We have
included in the table values for A, the depression of the freezing
point (corrected for under cooling), and the “‘average molecular
weight’? of the solutes.

Certain of the samples (nos. 9-14 and 17-21) were collected for
another purpose by Mr. RoBertT NEWTON, and the significance of
the various values will be discussed by him in a later paper. It is
sufficient for our purpose to point out the difference between nos.
- Ir and 14. We have here two wheat saps differing approximately
3 per cent in the freezing point depression (and consequently in
osmotic pressure), and at the same time differing by nearly 300
per cent in total solids. This difference can only be due to a differ-
ence in colloidal content, a fact that has been proved by NEwTon,
using several other methods. Had we been concerned only with
determinations of osmotic pressure, electrical conductivity, and
hydrogen ion concentration, we might have concluded that these
saps possessed practically identical physico-chemical, properties,
whereas such a conclusion is far from the truth.

Sample no. 21 is a wheat sap dialyzed completely free of sugar
and electrolytes, and represents the non-dialyzable colloidal mate-
rial. It will be noted that the refractometric method measures
this colloidal material quantitatively. Newton recently had
occasion to prepare, in this laboratory, gum acacia sols containing
I, 2, 3, 5, 7, and 10 per cent of highly purified gum acacia, and refrac-
tometric readings for total solids on the resulting solutions gave
values corresponding with those of the weighed gum acacia which
had been added to make the sols.

* Calculated by aid of published tables. Cf. Harris, J. A., and GorTNER,

Tables of the relative depression of the freezing point, 1860/A, to facilitate the
calculation of molecular weights. Biochem. Bull. 3:259-263. 1914.

312 BOTANICAL GAZETTE [NOVEMBER

One great advantage of the proposed method is that only two
or three drops of sap are required for the determination. A film of
sap is placed upon the prism, the prism is closed, and as soon as the .
thermometer inclosed within the prism has reached 20° C. the read-
ing of the moisture content can be made. The entire procedure
need not take more than two minutes.

The column “Moisture by refractometer” is read direct from
the scale of the instrument, the next column was obtained by weigh-
ing 10-20 gm. of the sap into a glass weighing bottle, and drying
to constant weight at room temperature in a vacuum desiccator
over sulphuric acid. The dried residue varied in color from a clear
green to light brown, and still retained the characteristic odor of
plant sap.

The next two columns were obtained by heating the residues
from the sulphuric acid vacuum treatment in a Freas vacuum oven
at 100° under a vacuum of 28 inches for the stated period of time,
and again weighing. It will be noted that in each instance there
is a higher moisture content indicated by the further drying in the
vacuum oven. We believe this to be almost entirely due to the
decomposition of carbohydrates, since there was always marked
browning or blackening of the residue, and a pronounced burned
sugar odor. In no instance was the residue again wholly water
soluble, and in every instance the water extracts of the residue
were dark opaque brown, with a =— ee Clo: Further
proof that this loss of weight is due to drates
is afforded by the fact that the loss in weight continues for a long
time, and constant weight is in many instances not reached even
after seventy-two hours’ drying in the vacuum oven at 100° C.

It will likewise be noted that in most instances the refracto-
meter indicates slightly more total solids (that is, less water) than
does the drying over sulphuric acid in vacwo. In every instance the
sulphuric acid in the vacuum desiccator darkened as the drying
progressed, indicating that volatile organic were dissolv
ing in the sulphuric acid. It is self evident that esters, alcohols,
ethers, and volatile oils are present in all plant saps, and none of
these would be estimated by any drying method. We believe,
therefore, that at least a part of the excess total solids indicated by
the new method are due to such volatile compounds, and that the

1922] GORTNER & HOFFMAN—MOISTURE CONTENT 313

refractometer reading more nearly expresses the true value of the
moisture content than can be obtained by any known method.

wv
.

UNIVERSITY FARM
St. PauL, MINN.

LITERATURE CITED

GorTNER, R. A., and Harris, J. A., Notes on the technique of the deter-
mination of the depression of the freezing point of vegetable saps. Plant
World 17:49-53. 1914

, On a possible ‘isto between the structural peculiarities of
onal and teratological fruits of Passiflora gracilis and some physico-
chemical] properties of their expressed juices. Bull. Torr. Bot. Club 4o:
27-34. 1913
Harris, J. ve Physical chemistry in the service of phytogeography.

a
Science N.S. 46:25-30. 191

7:
———., On the osmotic concentration of pe tissue fluids of phanerogamic

qichpics. Amer. Jour. Bot. 5:490-506. 1
5.

————, On the osmotic concentration of the tieeue fluids of desert Loran-
shacese: Mem. Torr. Bot. Club 17:307~315. 19

Harris, J. A., and Gortner, R. A., Sicha cheanical properties of vege-
table saps. II. A comparison of the physico-chemical constants of the
juice of apples and pears of varying size and fertility. Biochem. Bull.
3:196-201. 1914.

Harris, J. A., GoRTNER, R. A., and LAwRENCE, J. V., Physico-chemical
properties of vegetable saps. I. A comparison of the physico-chemical
constants of the juices expressed from the wall with those from the included
capillary whorl in proliferous fruits of Passiflora gracilis. Biochem. Bull.
4252-78. IQIs.

———., The relationship between osmotic concentration of leaf sap and
the height of leaf insertion in trees. Bull. Torr. Bot. Club 44: 267-286. 1917.
———,, The osmotic concentration and electrical conductivity of the tissue
fluids of ligneous and herbaceous plants. Jour. Phys. Chem. 25:122~146.
1921.

Hanes: J. A., and Lawrence, J. V., Cryoscopic determinations on tissue
fluids of plants of Jamaican coastal deserts. Bor. Gaz. 64:285-305. 1917.
, The osmotic concentration of the sap of the leaves of mangrove
trees. Biol. Bull. 32: 202-211. 1917.

, The osmotic concentration of tissue fluids of Jamaican montane
rain forest vegetation. Amer. Jour. Bot, 4:268-298. 1917.

, ———, On the osmotic pressure of the tissue fluids of Jamaican Loran-

neces parasitic on various hosts. Amer. Jour. Bot. 3:438-455. 1916.

s, J. A., Lawrence, J. V., and Gortner, R. A., The cryoscopic
aici of ceprenied vegetable saps as related to local environmental
conditions in the Arizona deserts. Physiol. Res. 2:1~-49. 1916.

MOISTURE CONTENT OF PEACH BUDS IN RELATION
O TEMPERATURE EVALUATIONS
EarRt S. JOHNSTON
(WITH TWO FIGURES)

The moisture content of peach fruit buds shows a marked
increase in late winter and early spring. Experiments performed
at the Maryland Agricultural Experiment Station in 1919 show that
moisture values based on the dry weight of buds increased from an
average ratio of 0.69 on January 7 to 3.65 on March 28. The
following year the average ratio increased from 0.73 on January
29 to 3.51 on April 1. Such marked increases come after the end
of the rest period. CHANDLER" has shown for several varieties of
peach that the rest period ends during the latter part of December
or the first part of January. The work of AUCHTER in 1919 (unpub-
lished), at the Maryland Experiment Station, shows that the rest
period for fruit buds of six peach varieties was completed by Decem-
ber 25. It is true that there is a fluctuation in the moisture content
of dormant buds, but such variations are slight in comparison with
those coming at the time the buds start their growth. Concerning
buds of the plum, STRAUSBAUGH? states:

During the period of dormancy the moisture content of the semihardy
varieties fluctuates with the temperature. Periods of low temperatures are
accompanied by a loss of moisture from the leaf and fruit buds, and higher
winter temperatures, which are seldom above freezing in Minnesota, by an
increase in moisture content.

It is interesting to note that the moisture content of his hardy
variety, Assiniboine, remained fairly constant during dormancy.

ince the increase in moisture content following dormancy
seems to be related to growth of the bud, an examination has been
made of the available moisture data of peach fruit buds and of
, W. H., Winter eae of peach buds as influenced by previous

treatment. oe Agric. Exp. Sta. Bull. 74. 1907.

2 StRAuSBAUGH, P. D., Dormancy sie hardiness in the plum. Bor. Gaz. 61:
337-357- 1921.

Botanical Gazette, vol. 74] [314

1922] JOHNSTON—PEACH BUDS 315

temperature data obtained during the last three years (1919-1921)
at the Maryland Station. The 1919 data include those previously
reported by JoHNnsTOoN.’ Fifteen Elberta and fifteen Greensboro
trees are averaged for this year’s data. The 1920 data have not
yet been reported, but are the averages of twenty-seven trees,
representing eighteen varieties. The buds of this year were col-
lected from an orchard that had been severely pruned the year
previous. The 1921 data are very meager, having been obtained
from two trees only, one an Elberta, the other a Greensboro.
Moisture determinations, however, were made more frequently
during this year.
Temperature evaluations

Three kinds of temperature indices have been applied to these

moisture data. In making use of the remainder indices, it is
TABLE I

MOISTURE CONTENT OF PEACH BUDS WITH sg melee TEMPERATURE
INDICES SUMMED FROM JANUARY I OF EACH

MoOIsTURE TEMPERATURE INDICES SUMMED FROM JANUARY I
Date Ratio of water Dail ae .
ly mean Physiological Exponential
content to ar | above 43°F. index index
19
SRAE Fe 0.69 14 12.6 2.9
POOIORSY Foon is 0.85 22 37.3 16.16
March 9.5 1.61 86.2 31.31
ASIC 88 oi gee es 3.65 173 218.8 59.83
1920
OUGARY 90. er 0.73 ° 2.5 1.00
MSD Fo 0.77 ° 10.3 5.16
DEAtCh 99s Bk 1.40 48 66.5 18.86
BOE Oe A eee 147 177.0 36.22
g2i
SOMUAtY O00) ace: 0.86 32 36.4 11.47
ODIGAIY 390s 0.99 37 51.0 18.14
POpreary 16-00%. cs 1.33 65 85.0 24.19
Peasy #8. ie 1.16 65 85.3 24.19
BRC Fo ese 1.46 120.7 32.56
Maren S60 2.27 185 252.3 45.10
MAK a ae. 2.72 223 294.0 50.67

assumed that 43°F. (6.1° C.) is the “zero” for growth and other
physiological processes, and that daily mean temperatures above

3Jo ee Eart S., An index of hardiness in peach buds. Amer. Jour. Bot.
2373-379.

316 BOTANICAL GAZETTE [NOVEMBER

43° are ‘‘effective” units. These daily mean temperatures (average
of daily maximum and minimum) above 43° have been summed
from January 1 to each date on which the moisture determinations
were made. ‘The physiological summation indices, as derived by
LIvINGsTON,’ were obtained from the daily mean temperatures,

i i A
0 50 106 150 200
REMAINOER INDICES

$ «. PO a 2 cag a ge bea PR Re 1 SR Rae MEE ed

Fic. t. I g
from January 1 for years 1919-1921.
and are likewise summed from January 1 to each particular date.
The chemical efficiency indices proposed by Livincston and
LIVINGSTON’ were summed from the indices corresponding to the
daily mean temperatures. These three kinds of temperature
indices are presented, together with the moisture data, in table I.

4Livincston, B. E., Physiological temperature indices for the study of plant
growth in relation to climatic conditions. Physiol. Res. 1:399-420. 1916.

5 Livincston, B. E., and Lrvineston, G. J., Temperature coefficients in plant
geography and climatology. Bor. Gaz. 56:349-375. 1913.

1922] JOHNSTON—PEACH BUDS 317

A general survey of the temperature indices in table I at once
shows that the 1920 season was colder and less advanced by April 1
than those of 1919 and 1921 on March 28 and March 11, respec-
tively. If the sum of the daily mean temperatures above 43° be
used as the criterion, it is seen that the season of 1921 was more
advanced on February 18 than the 1919 season on March 7, and
the season of 1920 on March 22. The moisture content of the fruit

TABLE II
MoIsTURE CONTENT OF PEACH BUDS WITH CORRESPONDING TEMPERATURE INDICES
FROM JANUARY I OF EACH YEAR, EXPRESSED AS NUMBERS RELATIVE TO
EACH SEASONAL RANGE, FIRST AND LAST VALUES BEING 0 AND I.00 RESPECTIVELY

| MolstuRE TEMPERATURE INDICES SUMMED FROM JANUARY I
DatTE
Ratio of water oa
Daily mean Physiological Exponential
Solent ol Sy above 43°F. index index
I9IQ
Mpa Gd ese wee Cand ° ° ° °
POCRUEIY Fi ikki Weenies 0.05 05 0,12 0.23
SICH Fos t'es:. ehh ks gone 4h 0.31 0.26 0°. 36 0.50
MOURN BB oy a cas I.00 I.00 1.00 I.00
1920
rpm ee Nee ge Oye ° ° °
Eck eeatoe ea beat 0.01 ° 0.04 0.12
PAUNCN 88. a VE es 0.27 Oi 5% 0.37 0.51
Beek es I 1.00 I.00 I.00
ied BO eek ri ° ° ° °
WOTORIY T2.o6oe 0.07 0.03 0.06 0.17
Wemmueary 28.0 es 0.15 0.17 0.19 0.32
WOMUASY 86. 55 is dae ss 0.16 0.17 0.19 0.32
Ma 8 eee 0.32 0.34 0.33 0.54
MAIC PE iis es 0.76 0.80 0.84 0.86
BUR S40 oe 4 ee I 1.00 I.00 I.00

buds on January 26, 1921, was practically the same as that on
February 7, 1919, and somewhat greater than that on March 2,
1920. Such early development of buds increases the danger of
fruit loss by spring freezes.

The moisture values given in table I have been plotted against
the summation values of the daily mean temperatures above
43° F., and are presented in fig. 1. The slopes of the 1919 and
1920 curves are practically the same, while that of 1921 is quite
different. There are apparently some conditioning influences at
work before January 1 that determine the slopes of these curves.

318 BOTANICAL GAZETTE [NOVEMBER

After the slopes have once been ‘predetermined,’ the increase
seems to depend mainly on temperature, either directly or indirectly.
It is thus possible to predict the moisture content of the buds for
any date after the first of January to the time the pink petals of

1.00 F

-90F

i 1920

1921

Jan, eae. Feb. Feb. Mar. Mar Mai
26 £2 18 25 5. ii it ee

I —Proportionate i increase in moisture content of eer buds (continuous
nes) ne corresponding increases in remainder indices (dash lines), deta
passe (dot lines), and exponential indices (dash-dot sins) for years 1919-1921

the buds begin to show. The daily mean temperatures and the
origin of the slope of the curve must be known. If the origin be
considered the first moisture value with its corresponding tempera-
ture summation after January 1, or after the end of the rest period,
then the slope can be determined from one other later moisture
determination.

1922] JOHNSTON—PEACH BUDS 319

The other temperature data in table I were also plotted against
the corresponding moisture values, but are not presented in graphic
form. ‘The curves obtained by using the physiological indices were
practically straight lines, and quite similar to those obtained from
the daily mean temperatures above 43°F. The relationship be-
tween the moisture and the exponential indices, however, was not
linear.

The data of table I have been rearranged so that the first reading
of each measurement for each year is zero and the last unity.
Within this range it is somewhat easier to compare the propor-
tionate amount of change in each measurement. These data are
presented in table IT, and in the form of graphs in fig. 2. The close
agreement between the moisture and the temperature indices
representing the summation of daily mean temperatures above
43° F. is readily seen. '

Conclusions

It is realized that the observations discussed in this paper are
somewhat limited in number, but nevertheless they suggest a
definite relationship between air temperature and the rate of
increase in the moisture content of peach fruit buds. There can
be little doubt, however, that other conditioning influences are
operative before January 1, that determine the manner in which
these buds responded to temperature.

AGRICULTURAL EXPERIMENT STATION

UNIVERSITY OF MARYLAND
CoLLEGE Park, Mp.

ALTERNARIA FROM CALIFORNIA
D. G. MILBRAITH
(WITH TWO FIGURES)

Frequent occurrence of a distinct spot on the leaves of cabbage
and cauliflower’ in certain sections of California led to an investiga-
tion of its causes and distribution. In culture media, infected leaf
tissue taken from the spot yielded constantly a form of Alternaria
which was found to be a species hitherto undescribed. Macro-
scopically the infected area appeared smooth, although somewhat
sunken, but lacked the profuse growth of conidia and the zonation
which characterize the lesions produced on leaves of cabbage by
Alternaria brassicae (Berk.) Sacc. The disease was found to be
restricted to that district of the state lying directly south of San
Francisco, where high relative humidity and a uniform temperature
prevail. In this district there have been planted annually about
2000 acres of cabbage and cauliflower for shipment to eastern
markets, and in view of the frequency of the occurrence of the
disease it may be the cause of a pathological problem in transit as
well as in the field.

The first symptom of the disease is the appearance of small
black specks about 1mm. in diameter. Often countless specks
appear simultaneously in the laminae. Infection occurs almost
entirely on apparently vigorous leaves, young as well as old; and
under conditions of high relative humidity the initial lesion may
develop into a spot ranging from 0.5 to 1 mm. in diameter in fourteen

ays. The spots are circular, somewhat sunken, black with a pur-
plish cast, the center being darker than the margin (fig. 1). The
color depends largely upon the color of the leaf, for upon pale green
leaves, as found on Winningstadt and Cannon-ball cabbage, lighter
spots are produced than on the dark green varieties of cabbage.
Sporulation of the fungus is sparse on still vigorous leaves, but
becomes profuse on yellow and detached leaves.

t The term cauliflower includes both cauliflower and broccoli.
Botanical Gazette, vol. 74] [320

1922] MILBRAITH—ALTERNARIA 321

The causal fungus grew luxuriantly on all common culture
media. Sporulation was abundant, and the mycelium was greatly
suppressed. En masse, the color of the colony is light olivaceous
on starchy media and dark olivaceous on nitrogenous media.

ee ae

Fic. 1.—Cabbage leaf showing abundant spots caused by Alternaria oleracea;
note absence of zonation characteristic of many Alfernaria spots.

Zonation in the colony was not visible. A description of the
fungus is as follows:
Alternaria oleracea, n. sp.
Hyphae short, greatly subordinated, straight, sparsely branched,

occasionally septate, very light olivaceous to hyaline, average
4.5m in diameter; conidiophores short, light olivaceous, short

322 BOTANICAL GAZETTE [NOVEMBER

branched, branches almost even in length, about 35 4; conidia
olivaceous to brown, echinulation none in culture four months old,
tapering very slightly to apical cell, tapering frequently absent,
apical cell frequently hyaline, conidia catenulate, as many as eight
in one chain, catenulation both on host and on culture media, longi-
tudinal septation very rare, considerable constriction of the walls
at septation, size of the conidia taken from artificially inoculated
cabbage leaf 29.7—61.2 uw by 8.7—-12.3 uw, average size 43.7 by 10.5 u.
Conidia developed on standard lima bean agar measured on the
seventh day as follows: 1-septate, 13.4-16 uw by 6.5—7.5 u; 2-septate,
17.5-18.7 u by 8.7 u; 3-septate, 20-26.5 u by 8-12 4; 4-septate,
34-36 mw by 12.5-14 mw; 5-septate, 30-38 w by 9.5-14 uw; 9-septate,
64.7-70 wu by 10-14 py (fig. 2).

Inoculation experiments with pure cultures were made on grow-
ing cabbage and cauliflower plants in the field and in pots under
control in glass cages, at the field station of the Office of Cotton,
Truck, and Forage Crop Disease Investigations, located at Alham-
bra, California. The varieties of cabbage used in these experiments
were Winningstadt, Late Drumhead, Early Jersey Wakefield, and
Fat Dutch, and the varieties of cauliflower were two selections
commonly grown in the San Francisco district. In Alhambra the
relative humidity of the atmosphere is considerably lower than in
the San Francisco district, where the disease is prevalent. On
account of this variation, open field inoculation did not progress
above a small speck. When the inoculated leaf was covered with
a wax paper sack in which there had been suspended a water-soaked
mass of gauze, lesions of normal size were produced readily. Suc-
cessful infections were produced by spraying conidia, suspended in
water, on uninjured leaves, and by wounding and inserting conidia.
Infections were obtained more rapidly in glass cages where high
relative humidity could be maintained. Within seven days lesions
ranging in diameter from 1 cm. to 1.5 cm. were produced. Similar
inoculation experiments were made with Allernaria brassicae
obtained from old cauliflower and cabbage leaves, and with Alter-
naria sp. from spots on tomato fruit. The former produced spots
with definite zonations, while the latter failed to grow on cabbage
and cauliflower.

1922] MILBRAITH—ALTERNARIA 323

Black leaf spot of cabbage has been attributed to the fungus
Alternaria brassicae for a long time. Harter and Jones? state
that the black spot fungus may attack the cabbage plant at any
stage of its growth, but it is not common except on the older leaves
in the field or on heads in storage. In the field it appears on the
lower or outer leaves of the maturing plant as distinct, roundish,

Fic. 2.—Types of conidia and conidiophores of Alternaria oleracea from cabbage

leaf

black spots, commonly marked with concentric brown zones.
Saccarpo? describes the fungus A. brassicae (in translation) as
follows:

Hyphae short, compact, little branched, even growth, in tufts;
conidia deciduous, elongate, fusoid, clavate, size 60-80 u by 14-
18 uw, 6-8 septate, muriform, olivaceous; fungus found on decaying
and old leaves of Brassica oleracea.

2 HARTER, L. » an Jones, L. R., Cabbage diseases. U.S. Dept. Agric. Farmers’

Bull. 925. figs. 13.
3 Saccarpo, P. ee ne Fungorum 4:546. 1886.

324 BOTANICAL GAZETTE [NOVEMBER

MAsSEE and Cookg give similar descriptions, except that CooKE
employs the term Macrosporium brassicae Berk., and describes the
conidia as antennaeform, rather longer than the peduncle. ELtiorr4
concluded that A. brassicae is morphologically similar to A. solani
(E. and M.) Jones and Grout, and placed both in the same group,
which he based upon having long, narrow, regular, tapering spores
with few longitudinal septae. It appears that the form of Alternaria
which the writer dealt with differs from A. brassicae both morpho-
logically and in the form of spot produced on cabbage. In view of
this difference, it is highly probable that a new species is involved in
the production of the leaf spot found in the San Francisco district, ©
and it is suggested that it be named Alternaria oleracea,

DEPARTMENT OF AGRICULTURE
Wasarincton, D.C.

4Eiott, Jonn A., Taxonomic characters of the genera Alternaria and Macro-
sporium. Amer. Jour. Bot. 4:439-476. pls. 19-20. 1917.

BASISPORIUM GALLARUM MOLL., A PARASITE OF
THE TOMATO!
G. B. RAMSEY
(WITH ELEVEN FIGURES)

While studying the various diseases of the tomato which are
found under transit and market conditions, the writer became
interested in an unusual fungus which was isolated from the Cali-
fornia crop of November 1919. Observations have been made in
the Chicago market during the past three seasons to see whether
the fungus recurred on California tomatoes, or whether it could
be found on those from Florida, Cuba, Mexico, and other tomato
shipping districts, but this particular fungus has not been isolated
again. The potential seriousness of this fungus as a wound para-
site of the tomato, however, and the fact that it has not been
reported as a plant pathogen, seemed to make it desirable to publish
this note.

The original isolation was made from a soft, red, blister-like
lesion near the blossom end of a ripe tomato. A luxuriant growth
developed upon the nutrient agar plate, and a great number of spores
were formed within a few days. The characteristic smooth, black,
subspherical spores borne singly upon their club-shaped sporophores
made it comparatively easy to place the fungus in the genus Basi-
Sporium.

Basis porium gallarum was established as a new genus and species
in 1902 by MoLtiarD,’? in order to properly locate and describe a
hyphomycete which he had found upon dead larvae of Lipara
lucens Meigen, within galls which this insect produces on Phragmites
communis Trin. He does not mention having found this fungus
before, or of later finding it upon any other host. So far as the

t Contribution from Research Laboratory on Market Diseases of Vegetables and
Fruits; Department of Botany of University of Chicago and United States Department
of Agriculture cooperating.

2 MoLutarD, M., Bull. Soc. Myc. France, p. 167. 1902.

325] {Botanical Gazette, vol. 74

326 : BOTANICAL GAZETTE [NOVEMBER

writer has been able to ascertain, no mention has ever been made
in the literature of the parasitism of Basisporium upon plants.*

Numerous inoculation experiments have shown conclusively
that the fungus is strongly pathogenic to the fruits of the tomato.
Pure culture re-isolations of Basisporium have been obtained many
times from the advancing edge of characteristic lesions produced
upon fruits inoculated with a transfer from the original culture.
Single spore cultures have been made and used in all experiments
described, in order to avoid all possibilities of contaminating organ-
isms.

All attempted inoculations upon unwounded surfaces of both
ripe and green tomatoes have failed. Inoculations in wounded
surfaces of ripe fruits have always produced the characteristic
decay described. Soft, red lesions, two inches in diameter, have
been produced on ripe fruits held in a moist chamber at room
temperature, within four days. An abundance of pale, smoke
colored mycelium is developed in a humid atmosphere. Ripe
fruits inoculated in such wounds do not decay at a temperature
of g°-10° C. Specimens have been held two weeks without showing
signs of decay when kept at this temperature.

Inoculation experiments with mature green tomatoes have
proved positive. It is quite evident, however, that the fungus
would grow much more rapidly and produce rot more quickly in
ripe fruits. Green tomatoes examined after being inoculated and
kept in moist chambers at room temperature for five days showed
only slight surface discoloration at the wound. The locule under-
neath, which was turning pink, showed discoloration and decay to
a depth of one-half inch.

The spores of Basisporium germinate readily in nutrient solu-
tions. In freshly expressed juice of green tomatoes, as well as that
of the ripe fruits, 90-100 per cent germination is obtained within
twenty-four hours at 20-21°C. At 34°-3 5° C. practically all
spores germinate within twenty-four hours; while at 9°-10° C. only
about one-half germinate in the green juice, and 80-go per cent in

‘In a letter, Miss A. E. Jenxrns of the Office of Pathological Collections, Wash-

ington, D.C., reports Basisporium as having been found on cultures from corn, wheat,
and dewberries.

1922] RAMSEY—BASISPORIUM 327

Fics. 1-~11.—Fig. 1, sporophore bearing three slightly immature spores; fig. 2,
mature spore; fig. 3, microtome section through mature spore showing thickness of
opaque wall; fig. 4, large hypha on surface of agar plate bearing two young fertile
hyphae; fig. 5, showing method of branching and spore formation at tips of fertile
aerial hyphae; fig. 6, large sterile mycelium taken from pulp of infected tomato;
figs. 7-9, spores germinated at room temperature in freshly expressed juice of ripe
tomatoes; fig. 10, showing hourly growth of germinating spores in Standard Nutrient
Salt Solution, at room temperature; fig. 11, spore germinated in sterile distilled water
at room temperature. (All drawings made with the aid of a camera lucida.)

328 BOTANICAL GAZETTE [NOVEMBER

the ripe juice. It is interesting to note in this connection that
although the spores germinate readily in fresh tomato juice at
g°—10° C., decay is practically if not totally prevented in both ripe
and green tomatoes at this temperature.

In sterile distilled water at 10° C. only a very few spores have
ever been observed to germinate. After three days, usually less
than 1 per cent have germinated. At room temperature about ro
per cent germinate within twenty-four hours, and 20-30 per cent
in forty-eight hours. The spores seem to absorb water rapidly,
and burst before having a chance to send forth a germ tube when
placed in sterile distilled water at 34°-35° C.

Basisporium grows well on most nutrient agars. Potato agar
plus 2 per cent dextrose has been used with excellent results in
culture studies of this fungus. The mycelium is white at first,
moderately thick and cottony, later turning pale smoke color as
sporulation takes place. Fine growth has been obtained at a
temperature as high as 35° C., but sporulation seems to be inhibited
somewhat at that temperature. Plate cultures held at g@-10° C.
for seven days developed only a very thin, flat growth whose radius
was 3mm. Taking the other 5 oalagece experiments into con-
sideration, it would seem that 10° C, is approximately the minimum
at which Basisporium will grow.

Spores are borne abundantly on the terminal as well as the lateral
branches of the small fertile hyphae. The spores are black, sub-
spherical, smooth, and have a tendency to be slightly conical on
top and flattened underneath. Average measurement through
the axis is 11.4 4, and through the transverse diameter 15.3 u-
The fertile aerial hyphae are 3.5~5 u in diameter. Large sterile
hyphae within decaying tissues of tomatoes and on surface of agar
in plate cultures are 12-17 w in diameter. These measurements
show a slight variation from those given by Mottiarp. The
original drawings also show a narrower constriction of the sporo-
phore at its junction with the spore. These differences are felt
to be of minor importance, however, and, although a new host is
involved, do not seem to justify the making of a new species.

Bureau oF Piant Inpustry
WasHINGTON, D.C.

BRIEF ER AR TICLEES

SAGENOPTERIS, A MESOZOIC REPRESENTATIVE OF THE
HYDROPTERACEAE

(WITH ONE FIGURE)

The question of the botanical relationship of the genus Sagenopteris
has been a debated one for a great many years. The genus was founded
by PreEst in 1838 for a Rhaetic (upper Triassic) form from south Ger-
many, and since that time a considerable number of species have been
described from all over the world, all of which come from rocks of Meso-
zoic age. The genus has been discussed by ScHIMPER, NATHORST,
Berry, and Sewarp. Nearly all students have recognized its pteri-
dophytic affinities, and many have suggested a relationship with the
so-called water ferns (Hydropteraceae). NATHORST was the most
emphatic advocate of the latter relationship, which was based upon
habit and venation of the vegetative parts. He fortified it by his dis-
covery in the Rhaetic beds near Palsjé in Sweden of fruitlike bodies,
which, aside from their resemblance to the sporocarps of the modern
Marsiiea, did not represent the fruits of any known Coniferophyte or
Cycadophyte present in the Rhaetic flora of Sweden, and therefore were
considered to be the sporocarps of Sagenopteris, being found in associa-
tion with the fronds of S. undulata Nathorst.

Somewhat similar remains, considered to represent the sporocarps
of Sagenopteris, have been recorded by Z1cno from the Jurassic of Italy,
and by Heer from the Upper Cretaceous of western Greenland (HEER
referred the latter to Marsilea). In describing the Lower Cretaceous
of Maryland in ro11, I considered the evidence sufficiently good to
warrant referring the Potomac species of Sagenopteris to the Hydrop-
teraceae. The most abundant of these Potomac species, and the only
one at all well characterized, namely S. elliptica Fontaine, has been found
to have a considerable geographic range. It is not only present in the
Patuxent formation (the oldest member of the Potomac group), but
occurs also in the Patapsco formation, which there is good evidence to
consider to be of Albian age. This species has also been recorded from
the Knoxville and Horsetown beds of California, the Kootenay formation
of Montana, and the Lower Cretaceous of Queen Charlotte Islands.

Botanical Gazette, vol. 74] [329

330 BOTANICAL GAZETTE [NOVEMBER

The occasion for the present note is the presence of this species
(S. elliptica Fontaine) in the lower part of the Blairmore formation of
western Canada, in association with characteristic sporocarps which
are almost identical with those described by Natuorst from much older
beds on the other side of the
world. The supposed sporocarps
from the Blairmore formation (fig.1)
probably belong to the same botan-
ical species as S. elliptica, but in
view of the fact that this has not
been demonstrated, and in accord-
S\ ance with paleobotanical usage,
¥ they may be named Sagenopteris
' canadensis, sp. nov. It may be
remarked parenthetically that not
all of the recognized species of
Sagenopteris based upon foliar re-
mains are clear cut, the European
Jurassic S. Phillipsii being not ob-

ct \ \}) viously different from S. rhoifolia,

\)) IN or from the European Lower Cre-

Ww" Wy Y taceous S. Mantelli. The last is

scarcely, if at all, to be distin-

guished from, and has often been

confused with, the American
S. elliptica.

The sporocarp, which it is believed belongs to the latter, may be
described as follows: Sporocarp hard and resistant, stalked, bean-
shaped, gibbous, slightly flattened at the sides, more recurved and
slightly more narrowly rounded at one end, about 5 mm. in length, and
about 3 mm. in height, with fifteen or sixteen transverse encircling veins
which are impressed, and appear as sulcae in the material, retaining
more carbonaceous matter because thicker, and appearing blacker than
the remainder of the wall; bands between these impressed veins lighter »
in color, and with a thin central line more or less developed.

SEWARD in his latest work refers Sagenopteris to the Hydropteraceae
tentatively, summing up his remarks with the statement that “decisive
evidence as to its position in the plant kingdom is at present lacking;
the inclusion of the genus as a possible member of the Hydropterideae
has still to be justified.”

Fig. 1.—Sporocarps of Sagenopleris
canadensis; X4.

1922] BRIEFER ARTICLES 331

It would seem that the discovery of bodies that have all the mega-
scopic features of sporocarps, that cannot be referred to any other known
elements of the associated flora, in association with foliage, which in
habit, form, and venation independently suggests comparisons with the
genus Marsilea, at two such remote localities as Sweden and western
Canada, is strong presumptive proof of relationship. Moreover, these
two occurrences are very different in age, thus showing no obvious
change in the sporocarps during the time that elapsed between the
Rhaetic and the mid-Cretaceous, a time interval of at least several
million years, and comparable in magnitude with the time that has
elapsed from the mid-Cretaceous to the present. If these sporocarps
preserve their appearance during the older interval, this conservative
feature becomes an argument of validity in comparing their latest
occurrence with the Marsilea sporocarps of the present.

e evidence, then, that Sagenopteris is related to the recent Hydrop-
teraceae is about as conclusive as we can hope to secure in the absence
of structural material, which is present in about o.ocoz per cent of the
cases with which the paleobotanist has to deal.—Epwarp W. Berry,
Johns Hopkins University, Baltimore, Md.

A BISPORANGIATE SPOROPHYLL OF
LYCOPODIUM LUCIDULUM

(WITH ONE FIGURE)

The occurrence of more than a single sporangium on a sporophyll in
Lycopodium is so unusual that it is believed the following account will
be of interest.

Bower? records a case in which a sporophyll of L. rigidum, from a
specimen in the Glasgow University Herbarium, bears “two sporangia
of slightly unequal size placed side by side. They are individually smaller
than the average sporangia in the near neighborhood on the same axis.”’
Bower’s statement would hold equally true for a similar case in L.
lucidulum recently found in the writer’s laboratory. As will be noted
from fig. 1, the larger of the sporangia shows the normal kidney shape
typical of the sporangium of Lycopodium, while the smaller has more the
form of a football. The relative thicknesses of the two stalks correspond
closely to the size of the sporangia. Both stalks are slightly lateral to the

* Bower, F. O., Note on abnormal plurality of sporangia in Lycopodium rigidum
.Gmel. Ann. Botany 17:278-280. figs. 18. 1903.

332 BOTANICAL GAZETTE [NOVEMBER

midrib of the leaf, the smaller being the farther removed. Normally
the stalk of the single sporangium is immediately above the midrib of
the leaf.

The origin of such a situation can only be conjectured. Since the
sporangium of Lycopodium arises from a transverse row of initials, it is
probable in this case that there
was a sterilization of arche-
sporial tissue within this row,
separating the two ends of the
row, each of which developed to
maturity ina practically normal
manner, producing the two dis-
tinct and separate sporangia.

The formation of the “sub-
archesporial pad” in the spo-
rangium of Lycopodium may be
regarded as a sterilization of
potentially sporogenous tissue,
which, while not producing
complete septation of the
sporangium, is suggestive as
a prelude to the complete septation which occurs in other forms, such
as Psilotum, as a result of the sterilization of complete plates of tissue.
In this case the sterilization may be thought of as having occurred
so early as to result in two completely distinct sporangia. Whether
the polysporangiate condition in Pteridophytes may have arisen in a
similar way is of theoretic interest, the synangium being regarded as
intermediary between the monosporangiate and the polysporangiate
conditions. On the other hand, the two sporangia may have arisen from
two distinct groups of initials.

OWER, concluding his note on L. rigidum, states that “it shows how
even the most rigid facts of morphological experience are liable to excep-
tion, and that this applies equally to spore-bearing members, in cases
where their forms seem most stereotyped.”

To summarize, (1) bisporangiate sporophylls in Lycopodium are very
rare, a single case of each being known in L. rigidum and L. lucidulum;
(2) the two sporangia may have arisen as a result of very early steriliza-
tion of archesporial tissue, or from two distinct groups of initials—
A. W. Dupter, Juniata College, Huntingdon, Pa.

Fic. I

1922] BRIEFER ARTICLES 333

A SIMPLE sayin FOR CONTROLLING
TEMPERATURES

(WITH ONE FIGURE)

In developing the control equipment for a humidity chamber in
which it was desired to control temperatures over long periods of time,
it was found essential to use a temperature control apparatus activated
by an electric current taken from the ordinary lighting circuit. Trouble-
some failures with dry cells and storage batteries led to the construction

ccH

Toluol

Fic. 1.—A, binding posts: to which wires from thermostat tube (G) are attached;
to left-hand binding post (B) i is attached one of the wires leading from heating unit;
, binding posts to which wires from main lighting circuit are attached (one of the
wires leading from heating unit is attached to right t-hand 1 post); D, “transformer
bell” electro
(to extreme right of armature bar is attached a piece of vabaped heavy « copper wire) ;
attached to lower part of right-hand magnet is a small piece of rubber cut from a
rubber stopper, which projects far enough beyond magnet bar to eliminate most
of the ‘‘chatter” or “buzz”? when coils are operating; 2, two glass vials (0. 75Xt. 5
inches) partly filled with mercury, into which points of the se copper wire are
immersed; wires leading from B are in contact with the mercury in vials; F, small,
3 volt, bell- -ringing, alternating current transformer which furnishes 6, 8, or 14 volts
as desired (here connected to furnish 8 volts, alternating current); be small single-blade
knife switch used to test action of coils at D; the asbestos-cover upon which
units A to F are mounted measures 9.5 11.5 inches, and is designed fot wall attach-
ment; use of transite board or other insulating material and mounting to reduce fire
risks is recommended.

334 BOTANICAL GAZETTE [NOVEMBER

of the apparatus shown in fig. 1. This is a modification of a somewhat
similar instrument secured through Dr. K. F. KELLERMAN, and used for
some time at the Laboratory of Forest Pathology at Madison, Wisconsin,
in controlling the temperature of a Bausch and Lomb incubator.

The main advantage of the apparatus here described lies in the fact
that the same current (110 volts, 60 cycle, alternating) which passes
through the heating units is used, after reducing the voltage to 6, 8, or
14 volts, to operate the relay (fig. 1D). The apparatus is simple,
comparatively cheap, and when once set up and adjusted needs little
attention. It will stand continuous service for long periods of time, and
when used in connection with a toluol and mercury filled tube (fig. 1G)
controls temperatures within a range of a quarter of a degree Fahrenheit.

When the mercury column in the tube (G) rises and contacts with
the fine wire held by the cork, the coils at D draw the armature bar up
to the poles of the magnet, the U-shaped wire is pulled free from the
mercury at E, and the current supplying the heating unit is broken, thus
shutting off the heat. A reversal of this action turns the heat on again.

At E the make and break of the current supplying the heat units is
very positive in action. There is no arcing of the current between the
mercury and the wire points, so long as the U-shaped wire is raised
sufficiently above the mercury surface. The small voltage of the current
passing through the mercury column in the tube (G) reduces the spark
to a minimum, and for this reason little trouble is encountered with
arcing, vaporizing of mercury, or clouding of the tube where contact
is made between the fine wire and the mercury. A metal cap with
adjusting screw carrying a fine platinum wire may be substituted for
the cork and wire as shown.—Ernest E. Hupert, Laboratory of Forest
Pathology, Bureau of Plant Industry, in cooperation with the Forest Products
Laboratory, Madison, Wisconsin.

CURRENT LITERATURE

BOOK REVIEWS

Yeasts

A few years ago a group of French savants arranged for a new Encyclo-
pédie Scientifique. Under the direction of TouLousE, some of the most dis-
tinguished scientists are attempting to prepare a series of complete and readable
monographs covering the whole range of science. The plan calls for about a
thousand volumes, classified under forty main sections of knowledge.

If GUILLIERMOND’s' volume on yeasts is a fair sample, this encyclopedia
will be indispensable to every school of science. This volume includes an
ample bibliography, index, and analytic table of contents. The introduction
defines the yeasts, morphologically and physiologically, and places them as “‘a
family of the Ascomycetes, known by the name of Saccharomycetes.” A
brief historical résumé concludes that three names will always be connected
with the study of yeasts, PAstreuR, HANSEN, and BUCHNER.

The first chapter deals with the morphology of vegetation and reproduc-
tion. The second one, on cytology, discusses the nucleus, metachromatic
bodies, and other particles, both in vegetation and reproduction. The meta-
chromatic bodies are stated to be composed probably of a compound of nucleic
acid. They are identical with A. MEYER’s volutin grains. Two chapters on
physiology are rich in material. The subjects of the following chapters are
phylogeny, methods of study and culture, identification of species, variation
of species, and classification. The second part is a systematic description of
the known genera and species. Constant reference throughout all the chapters
to the little known Schizomyces and Zygosaccharomyces adds much to the
interest of the work. Every page of this admirable volume is full of clear,
terse statements of observation, and carefully balanced discussion. It is
rare for as keen an investigator to have such a lucid and logical style.

The translation of GUILLIERMOND by TANNER? is really a new edition. In
bringing the work up to date, GUILLIERMOND has been responsible for the
morphology, phylogeny, and classification, and TANNER for the physiology.
Most of the text, however, is carried over without change. Unfortunately,
the translation has been poorly done. Almost every page of the English

? GuILLIERMOND, A. T., Les Levures. II. pp. 565. Paris: Octave Doin et fils,
1912.

* GurtireRMmonD, A. T., The y in coll
oration with the original fetes | Aang Fr. “W. TANNER. pp. pono ” New York: oes
Wiley and Sons. 1920.

335

* 336 BOTANICAL GAZETTE [NOVEMBER

edition furnishes distressing mistranslations. When the Frenchidiom ze .. .
que is translated as a flat negative, the author is made to say the exact reverse
of what he means, and the rest of the paragraph becomes absurd. The French
use of the article has been carried over literally, even where it fits the English
idiom! Again, where the author says, for example, a fluid may reach a certain
ee the faithful translator puts it, is able to reach. ‘‘ Matiéres hydro-

”? becomes ‘“‘hydrocarbon materials,” in heavy-faced type; and the
aah discusses sugar, cellulose, and glycogen! Perhaps the consistent
reference to WAGER as WAGNER in the text is an error of proofreading, for
the name is correct in the bibliography and in the French text. The American
book is very well printed, with large, open, legible type, but no one can safely
use it without having a copy of the original at hand, or at least without having
enough knowledge of French to read the original author’s meaning between
the lines. —H. S. CoNARD.

NOTES POR STUDENTS

Electrons in photosynthesis.—An attempt has been made by Drxon and
Poot’ to interpret photosynthesis in terms of the electronic theory. On the
basis of photo-electric phenomena in sensitizers of photographic films, and the
absorption spectra of chlorophyll, they believe that the first action of light is to
disturb electrons in the chlorophyll molecule. Experiments were made to de-
termine whether the electrons were actually ejected by the incident radiation, or
whether the disturbances were too weak to do more than displace the electrons
within groups of atoms, or from molecule to molecule of chlorophyll.

By delicate electrometer measurements they were able to establish the
occurrence of a slight photo-electric effect in chlorophyll under illumination,
but this effect is apparently produced by ultra violet radiations, not by those of
visible frequencies and synthetic activity, for they find that the effect is mag-
nified about 2000 times by use of a light rich in ultra violet rays. Quantitative
use of the data showed that possibly 75 electrons per square centimeter per
second might be ejected from a layer of chlorophyll by light from a 500 watt
lamp. In terms of energy, this effect is utterly negligible, for the actual syn-
thesis of food in plants goes on at a rate which would require about nine trillion
times as much energy as these ejected electrons could supply. It is necessary to

electronic bombardment. If this be true, then the synthetic reactions must
concern the chlorophyll molecule itself, and the electrons are merely shifted
from atom to atom, or molecule to molecule, as in ordinary chemical reactions.
These shiftings, of course, will alter linkages, and change the chemical character
of atomic groups, probably rendering inactive groups of atoms reactive. Such

‘3 Drxon, Henry H., and Poorer, Horace H., Photosynthesis and the electronic
theory. Sci. Proc. Roy. Dublin Soc. 16:63-77. 1920

1922] CURRENT LITERATURE 337

a conception favors the chemical theories of photosynthesis which assume that
chlorophyll itself enters into the reactions, rather than those which assume
that the synthetic reactions are performed externally to the chlorophyll by
means of energy absorbed and transformed by the pigments.

That the light actually displaces electrons seems to be proved by Drxon
and BALL‘, who show that the chlorophyll acts as a sensitizer of photographic
films at the temperature of liquid air, a temperature believed to be too low
for chemical reactions other than electronic displacement. They suggest that
chlorophyll a and 8 might have an important connection in the synthetic pro-
cess, as indicated by the following equations:

C;sH7,0;N,Mg+CO.>C,;H,.OsN,Mg+ HCHO

(chlorophyll a) (chlorophyll 8)
C;;H»OsN,Mg+ H,0—>C,;H,,0;N,Mg+O,
(chlorophyll 8) (chlorophyll a)

e fact that in vitro experiments with chlorophyll a and CO, do not yield
formaldehyde could be explained by accepting W1LisTATTER’s assumption
that before the CO, will react with the chlorophyll it must first be combined
into a carbamino acid, which can then be decomposed by the reactive group
in the chlorophyll, which group was rendered reactive by the electronic shifting
due to light.

Regardless of whether the discovered facts are sufficient to establish the
relations between Siecenonie: eapateent and aynthess a. carbohydrates,
the attempt made by
the newer conceptions os ae i checikey is ‘praiseworthy, and will be
followed with great interest by physiologists. Ultimately all the chemical
processes of life must be interpreted along similar lines.—C. A. SHULL.

The mycoplasm theory.—In two brief notes in English and an extended
discussion in German, ErrkssoNs makes a spirited defense of his mycoplasm
cory. Only aactleliad reference is made in these papers to the work on the
grain rust, on which the theory was established, but the previously published
conclusions on the downy mildew of spinach, the late blight of potato, and the
hollyhock rust are reaffirmed, critics are replied to, not without acerbity, and
in the case of the hollyhock rust new observations and experiments are adduced
which, the author believes, still further support his hypothesis, of which he is
not only the originator, but has been, to date, almost the sole protagonist. In

4 Drxon, HENRY and Batt, NIGEL G., os se si the electronic

sme IL. Notes Hee Heal Trinity Coll., Du blin 3 205.
get stabs The mycoplasm theory, is it feaatas or — a Phytopath,

II: 3 — itt
— ° life of bes aegis Mont. within the host plant and on its
surface. Phytopath 112450-4
mn des aliciotel Izes (Puccinia malvacearum Mont.) in und
auf der Neicplencs, Handl. Kungl. Svensk. Vetensk.—Akad. 625:1-190. figs. 31. 1921.

338 BOTANICAL GAZETTE [NOVEMBER

the first paper he lists additional pathogens which he believes have a mycoplasm
stage in their life histories, making a total of fifteen rusts

for which this seen combination of host and fungous protoplasm is claimed
as proved or suspec

Additional aes are yosmetind which lead the author to reaffirm, with some
modifications, his previously expressed belief in the physiological dimorphism
of the teleutospores, as evidenced by their mode of germination; one sort, in
moist air, giving rise to long hyphae terminating in chains of conidia; the other
kind, under the same conditions, germinating in ordinary teleutospore fashion,
producing basidiospores. The latter, on penetrating the host tissue, give rise
at once to an intercellular mycelium from which new sori develop in a few days,
and are therefore the agencies by means of which the rapid spread from plant
to plant is effected. On the other hand, the conidia discharge their contents
into a host cell, with the contents of which they form an intimate intracellular
protoplasmic union, that is to say, a mycoplasm, which multiplies within the
host, even entering the embryo, thus forming the hibernating stage of the
fungus. In spring, with the renewal of growth in a dormant plant or the ger-
mination of a seed, the fungus element separates out from the mycoplasm,
organizes an intercellular mycelium, and eventually produces sori. Numerous
observations are reported tending to show that the rapid spread of the disease
from plant to plant occurs only late in the year, when basidiospores are being
produced, the summer (conidial) infections not appearing until the following
season. series of experiments is reported in which the host plants were
watered with weak solutions of copper sulphate. This resulted in a perceptible
diminution in the number of summer pustules which appeared, these being due,
according to the view outlined, to the conidial infections of the previous year,
the fungus wintering over within the host. The copper solution was of no
avail against the late summer basidiospore infection. Endeavors to inject
the copper solution into the leaves and stems were unsuccessful. Without
attempting to summarize the voluminous data, it may be admitted that the
evidence seems to favor the view that the fungus may winter over within the
host tissues. This is by no means a proof, however, that it is in a state of myco-
plasmic symbiosis with the host. Furthermore, it must be regarded as a serious
oversight that no notice whatever is taken of the carefully planned experiments
of BaiLEy,® which seem to point very decidedly to conclusions quite oppos
to those of Er1ksson. Certainly the facts in the case must be explained, and
the mycoplasm theory admittedly offers a theoretical explanation. The wide-
spread opposition to it is based on the feeling that the facts may ultimately be
accounted for satisfactorily without the theory. If this shall prove to be

impossible, the mycoplasm “gtr — erect as a oe hypothesis, which,

however, must be confirmed by f. y ] evidence than has

et been presented before it can b ded tablished fact.—G. W. Martin.

6 Ann. Botany 34:173-200. 1920.

1922] CURRENT LITERATURE 339

White pine blister rust.—The present state of our knowledge concerning
this most important tree rust is ably summarized by SPAULDING? in a recent
contribution from the Bureau of Plant Industry. The extensive scope of the
treatment is partially indicated by the bibliography of 180 titles. The opinion
is expressed that Cronartium ribicola is of Asiatic origin, that it spread through-
out Europe during the nineteenth century, and was introduced into North
America on young trees of Pinus Strobus after 1900. The life history of the
fungus and its relations with its various hosts are exhaustively discussed. It is
regarded as established that the overwintering is chiefly by the mycelium in the
bark of living pines, and that it is in this stage that the long migrations have
taken place, but it is also recognized that the fungus may overwinter on Ribes.
The attempts which have been made to control the disease are reviewed, and
the conclusion is reached that its eradication is impossible except in the case
of small isolated advance infections, but that the systematic removal of all
Ribes in white pine forest areas will kee i the disease in check, and that this
method is both practicable and profita

Eriksson’ renews his contention a the Peridermiums on Pinus Strobus,
P. silvestris, and P. Cembra are biological races of a single species in which the
specialization is not yet definitely fixed. He believes that he has evidence that
the white pine blister rust is transmitted by diseased seed and also from pine
to pine. The direct evidence presented is not of the sort that can be regarded
as final. To supplement it, so far as the matter of the spread from pine to pine
is concerned, great emphasis is laid upon the undoubted autoecism of closely
related species, veh foo stress upon the results of Haack. These, it is
interesting to note, are characterized as worthless by SpauLpiING. The latter
admits, however, that the ks of MEINECKE and of Hepccock on Peridermium
cerebrum, and that of KLEBAHN on Peridermium pini “throw doubt on the
strict heteroecism of the aeciospores of all stem-inhabiting pine Peridermiums.”’
This is very far from proving the autoecism of the aecidiospores of Peridermium
strobi, as ERIKSSON seems to assume. The point is obviously one of funda-
mental importance, and it is to be hoped that the experiments now under way
in this country will shortly throw more light upon it. ERrKsson finds in recent
American and European experiences of the overwintering of the fungus on Ribes
a complete justification of his own early expressed belief concerning this phase
of the problem. That such overwintering occurs cannot longer be doubted.
That it is of any great penta in the perpetuation of the disease is still very
questionable.—G. W. Mar

soetes.—OsBoRN? has obtained some very interesting results from an
investigation of Isoetes Drummondii, a species widely distributed in certain

7 SPA G, Perey, Investigations - sy white pine blister rust. Bull. 957.
US. Dene A Aare. Pp. roo. eet 6. figs. 13.
RIKSSON, JAKos, connection oe Peridermium strobi Kleb. and one
posable ribcle Dietr., is it boobs ornot? Acritical review. Arkiv Botanik 18:1
gs. 6.
Oe , T. G. B., Some observations on Isoetes Drummondii A. Br. Ann.
Botany 36: 41-54. figs. 15. 1922.

340 BOTANICAL GAZETTE [NOVEMBER

parts of South Australia. “It grows terrestrially in seasonal swamps during
the period of winter rainfall. During the dry summer it aestivates, as do the
other geophytes with which it is associated.”” The stock is buried, and during
the vegetative season only a small rosette of linear leaves is visible above the
soil. On approach of the dry season, the leaves dry up and become detached,
leaving their tough bases and sporangia upon the stock, wholly buried and
invisible.

This species seems to be unique among Pteridophytes in its method of spore
liberation. There is a special mechanism for freeing the spores which depends
for its action upon saturation with water, not upon dryness (as in other Pterido-
phytes). Other peculiar features of the species are in the nature of preparation
for this remarkable method of spore dispersal. In his summary, OsBoRN de-
scribes the performance as follows: ‘Early in the rainy season, the hardened
bases of the sporophylls are forced above the surface of the soil in a projectile-
like mass, carrying with them the sporangia, by the expansion of certain pads
of mucilage cells formed at the close of the previous vegetative season on the
extreme bases of the sporophylls and from the superficial cells of the leaf-
bearing cortex. About the same time the leaves of the new vegetative season
begin to appear. The imbricate mass of sporophyll bases breaks up upon the
surface of the soil, and the spores are set free by a tearing away of the sporan-
gium wall from its attachment to the sporophyll when sodden. This is due to a
difference between the tension of the inner and outer surfaces of the sporangium
wall when saturated, and results in an eversion of the wall.”

TAKAMINE” has investigated the gametophytes of Isoetes japonica and I.
asiatica, with some interesting results. The female gametophyte of J. paver
usually has five or six archegonia, but sometimes ten or more. hen fertiliza-
tion occurs in one of them, the others degenerate; but in rare cases when
fertilization occurs in two or more archegonia, several embryos are developed
up to certain stages. Occasionally megaspores and microspores were found
in the same sporangium. In J. asiatica the 2x chromosome number is twenty-
two, while in J. japonica it is “forty-three to forty-five.”” Hybrids of the two
species were produced, an account of which is promised later.—J. M. C.

Complexmutation.—As the term mutation is now being used by geneticists,
its application is restricted to “locus changes”? on the chromosomes. At one
place on one chromosome, mutation takes place, the effect of the change being
so restricted as to involve only a single factor; other factors, although lying
very close on the same chromosome, remain unchanged. Save for “ defi-
ciency,” noted by BriwcEs" (which is evidently of a different category), all
mutation seems to have been of this very localized type. It is perhaps sur-
prising that no clear cases of mutations involving simultaneous changes 1n

%” TAKAMINE, N., Some observations in the life history of Isoetes. Bot. Mag.
big 35:184-190. figs. g. 1921.
™ BripcEs, C. B., Deficiency. Genetics 2:445-405. 1917.

1922] CURRENT LITERATURE 341

several factors in one region of a chromosome have been discovered. NILsson-

HLE* now claims to have such a case, and calls it “complexmutation.”

Normal wheat mutates to bearded speltoid, involving a simultaneous change

in two closely linked factors. Among the F, progeny of normal mutant

appear a few bearded normal type and beardless speltoid, but only a very few,

cae to we very close linkage ZS the ve aad peers. Tn Snorer case
1 41 4

M. C. Couties.

Ozark forests.—The Ozark region, as covered by PALMER’ in this recon- .
noissance, is defined as occupying the southern half of Missouri, a narrow spur
crossing southern Illinois, the northwestern part of Arkansas, and a long tri-
angular strip in eastern Oklahoma. The two topographic divisions of this
uplifted region, lying midway between the higher mountains of the east and
west, are the flat-topped dome of the northern plateau with an average altitude
of 300-500 m., and the southern Boston Mountains with a few p
600 m. It is a hill region surrounded by fertile plains, and possessing a rather
abundant rainfall. Floristically there are no distinct floras corresponding to
the topographic divisions, although the southern parts of the region, including
the Boston Mountains, have a heavier forest growth richer in types than the
northern, and include such southern forms as Aesculus discolor, Tilia floridana,
Rhamnus caroliniana, Ilex decidua, and Magnolia acuminata.

The larger portion of the report is occupied by floristic notes on various
sections of the flora and on certain genera and species. The author is con-
vinced that in the region as a whole there is a demonstration of the gradual but
actual encroachment of forest upon prairie lands.—Geo. D. FULLER.

Temperature and nodule development.—Using soil temperatures rangi
from 12° to as high as 40° C., Jones and TIsDALE” have studied the effect of
these temperatures on the development of nodules by alfalfa, red clover, soy
beans, and field peas. The results as to the number of nodules developed were
not so very consistent, but when the dry weight of the nodules was determined,
it was found that the greatest ee in the case of the soy bean, was at
24°C. This effect of temp lated with
a corresponding effect on root and shoot development. It is pointed out in
the paper that the real question in a study of this kind is not the effect of tem-
perature on the number of nodules developed by the plants, or on the volume
of these nodules, but the effect on the amount of nitrogen fixed in the nodules.

% Nitsson-EuLe, H., —— Allelomorphe und Komplexmutationen beim
Weizen. Henan tas 1:277-311.
ALMER, E. J., The forest at of the Ozark region. Jour. Arnold Arboretum
22216-232, 1921.
4 Jones, F. R., and Tispae, W. B., Effect of soil temperature upon the develop-
ment of nodules on ‘the roots of certain legumes. Jour. Agric. Res. 22:17-31. pls. 1-3.
e

342 BOTANICAL GAZETTE [NOVEMBER

Some data in regard to this point are presented. While this is a preliminary
paper, the results obtained and the statements as to methods of attack on a
problem of this kind are suggestive to workers in this field.—S. V. Eaton.

Response of apple trees to nitrogen fertilizers -—Nitrogenous fertilizers

‘nitrogenous fertilizers causes increased setting of apples, accompanied ad an
increased nitrogen content of the spurs. In the case of non-bearing trees,
increased vegetative growth is caused. Different kinds of quickly available
fertilizers had much the same effect. At the time of fruit bud differentiation,
the spurs of the spring fertilized trees showed less starch than the spurs of the
check trees, so that the spring application of nitrogenous fertilizers would not
be expected to favor this process. The accumulation of nitrogen in the spurs
just before growth starts in the spring is the greater the later the nitrogenous
fertilizers have been applied the preceding season. It is a pleasure to see the
horticulturists thus attacking the fundamental problems of their subject.—
S. V. EATON.

Vegetation of Illinois.—The recent publication of the 14th annual volume
of the Transactions of the State Academy of Science"S shows about one-third of
the volume devoted to ict of botanical and lent scological studies. sce
State Forester, R. B. MILLER
of the southern portion of the state, and in collaboration with Geo. D. FULLER
examines in some detail the conditions of tree growth and the forest types
existing in a portion of Alexander County. W. G. WATERMAN makes a pre-
liminary report on the bogs of the northern portion of the state, while W. B.

RENICH contributes a study of growth as related to size of seed, and A. B.
REAGAN has some interesting ape on sig a aa of the Bois Fort Indian
Reservation, Minnesota.—GEo. ULLE

Mosaic disease of tobacco.—PaLm” has investigated the mosaic disease
of tobacco, and has reached the conclusion that it is due to a causal organism.

*s Hooker, H. D., Certain acy of apple trees to nitrogen Sma of dif-
ferent kinds and at different seasons. Mo. Agric. Exp. Sta. Res. Bull. 50. 1-18. 1922+
© Transactions of the ek State Academy of Science. npc annual
meeting. 1921. 14: pp. 326. 1922.
7 Pat, B. T., Is the mosaic disease of tobacco a chlamydozoonose? English
translation by P. G. Wison. Bull. Deliproefstation Medan-Sumatra. no. 15-
pp. 10. 1922.

1922] ; CURRENT LITERATURE 343

His preparations of the diseased tissue show fairly large irregularly shaped
corpuscles and very small granules, both clearly foreign elements, being entirely
absent in healthy tissue. The author agrees with IwANowsxktas to the probable
interpretation of the foreign elements, namely, ‘that the minute granules are
very small bacteria, carriers of the virus, and further that the irregularly shaped
corpuscles must be considered as a pathological product of reaction of the virus
carrier on the cell plasm.” This causal organism is thought to be a species of
Strongyloplasma, and is named S. Iwanowski in honor of its original discoverer.

Effect of age on plant structure.—Miss TELLEFSEN" has studied the effect
of age upon certain tissues of Salix nigra. This species was chosen chiefly

tematic become larger. The average area of vein islets in leaves from older
trees is smaller than average vein islet areas of leaves from younger trees, the
amount of vascular tissue increasing with senility, thus reducing the average
area of vein islets —J. M

Leaf-skin saci) lied SAUNDERS” has reached the conclusion that the
surface tissue of the seed plant shoot is of foliar origin, meaning that the leaves
are decurrent, not merely those that are usually called so, but all leaves. In
the same way the superficial tissue of the hypocotyl are derived from the cotyle-
dons. This so-called leaf-skin is formed by the “downward growth and exten-
sion of the leaf primordium, which keeps pace with the extension of the central
axis with which it is fused. In the case of flowering stems the leaf-skin is formed
by the bracts (when present) and the outermost sepals.” Miss SAUNDERS
has gone into many details as to the extension of a aaee leaf surface in relation
to the different eae of phyllotaxy, the various patterns deve loped, and
other features.—J. M. C.

Intrafascicular cambium in monocotyledons.—Mrs. ARBER,” in continuing
her investigations of the occurrence of intrafascicular cambium in monocotyle-
dons, has added Alismaceae, Aponogetonaceae, and Hydrocharitaceae to the
list of monocotyledonous families, in some member of which this tissue has been

% TELLEFSEN, Marjorie A., The relation of age to size in ene root = and
vein islets of the leaves of Salix nigra Marsh. Amer. Jour. Bot. 9: 121-1309.

77 SauNDERS, Eprtu R., The leaf-skin theory of the stem: a aeiieition of cer-
tain snatomico-physiological relations in the Spermatophyte shoot. Ann. Bota
36: dees Sigs. 34.

ER, AGNES, pikes on eeepc cambium in monocotyledons. V.
Ann. om 36: 251- 256. Sigs. 8.

344 BOTANICAL GAZETTE [NOVEMBER

observed, bringing the number of such families to twenty-two. Incidentally,
she shows that LicNrER was probably mistaken in attributing only phloem-
forming activity to the cambium in the petiolar bundle of Arum maculatum,
since she finds secondary xylem in the corresponding bundles of a closely related
species (A. italicum), and L1GNtER’s figures indicate that the same process takes
place in A. maculatum.—J. M. C

Heat of inversion—A careful measurement of the heat of inversion of
sucrose by invertase has been made by Dixon and BAtt,?! who used a thermo-
couple differential calorimeter in vacuum flasks for the determination. Their
results confirm the value found by Brown and PICKERING many years ago,
the mean of all results being 3.83 calories for each gram molecule of sugar
inverted. The method is more accurate than the heat of combustion deter-
minations of this value-—C. A. SHULL.

Fungus in Pellia.—RIDLER” has described the life history of a fungus occur-
ring in a definite zone in the thallus of Pellia epiphylla. It was found to occur
in the cells of the sporophyte, from which it was isolated, and identified as a
species of Phoma. The fungus kills the protoplasts of the infected cells of
the gametophyte, which ultimately become brown. The effect on the sporo-
phyte is twofold: the contents of the cells are killed, and the cell walls are alse
wholly or partially absorbed.—J. M. C

Mycorhiza of conifers.—McDovucatv* has identified two mycorhizal fungi
from the roots of Picea rubra as belonging to the genus Cortinarius, and
described a ap soo aa mycorhiza of Pinus Strobus. He reiterates his opinion
that these ect hic mycorhizal fungi are of no benefit to the trees concerned,
and probably do them no great harm, although truly parasitic in their relation-
ship. —G. D. FULLER.

Rocky Mountain flora.—RypBERG% has continued his studies of the mon-
tane regions of the southern Rockies, already noted in this journal,?s by investi-
gating the aquatic and grassland associations, as well as the flora of the sand
hills, dry ridges, and rock slides. The plants of these habitats are listed as
eastern, western, and endemic.—Geo. D. FULLER.

Dixon, H. H., and Batt, Nicet G., A determination by means of a differential
calorimeter of the heat produced oe g the inversion of sucrose. Notes Bot. School,
Trinity Coll., Dublin 3:121-132. 1922.

= RIDLER, W. F. F., sap tee present in Pellia epiphylla (L.) Corda, Ann.
Botany a: peli Jigs. 8.

73 McDouGALL, W. B. EES of coniferous trees. Jour. Forestry 20:255-
260. figs. 3. 1922

24 keneake , P. A., Phytogeographical notes on the Rocky Mountain region. X-
Grasslands and other open formations of the montane zone of the southern Rockies.
Bull. Torr. Bot. Club 48:315-327. 1921.

25 Bot. GAZ. 71:336. 1921.

VOLUME LXXIV NUMBER 4

THE

BOTANICAL GAZETTE

December 1922

ECOLOGICAL FACTORS IN REGION OF STARVED
ROCK, ILLINOIS
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 299
FRANK THONE
(WITH FIVE FIGURES)
Introduction

The work of Cow tes (5) in calling the attention of the then
newly differentiated science of plant ecology to the concept of plant
associations as stages in successions, not as entities complete and
final in themselves, but rather as steps in the evolution of social life
in the plant world, was of far reaching influence in determining the
development of ecology in America as a dynamic science, as the
study of a progress rather than as a mere set of methods for
the description of.states. CowLrs was also the first to emphasize
the importance of topography as a general control over other
factors that directly influence the activities of plants.

The earlier work in this field contented itself with pointing
out the general effects of topography as a modifier, within a given
region, of the climatic factors. It indicated the direction of such
modifications, but only estimated their extent; it was qualitative
rather than quantitative. It was, however, only natural that as
time passed students of ecology should desire to gain a more exact
knowledge of the factors controlling plant communities and their
development, and a good share of the work now being done in Ameri-

345

346 BOTANICAL GAZETTE [DECEMBER

can and British ecology concerns itself with the measurement of
such factors as soil moisture, soil chemistry, temperature of both
soil and air, evaporating power of the air, and intensity of sunlight.
With the cooperation of ecological plant physiologists, a number of
more or less satisfactory methods for the measurement of these
factors have been evolved. Among the many workers on the prob-
lems of soil moisture, BR1Gcs and SHANTz (3) may be cited for their
development of the wilting coefficient concept, Br1ccs and McLANE
(2) for the moisture equivalent idea, ALway (1) for the hygroscopic
coefficient, and Livincston and Koxersu (11) for the invention
of the so-called soil points. Thermometric data were among the
earliest to be gathered, although they are still among the least
satisfactorily interpreted; special citations appear to be super-
fluous. Exception might be claimed for the “‘life zone” idea best
developed by Merriam (15), but this is regional-climatic rather
than local and topographic.

Modern ecological work in the measurement of the evaporating
power of the air dates chiefly from the re-invention and populariza-
tion by LivincsTon (8, 9) of the porous cup atmometer. From
time to time numerous attempts have been made to develop photo-
graphic and other methods for a field study of sunlight intensity,
but none of them has been very satisfactory to students of plant
activities. PULLING (16) gives a concise review of the work in this
field. About the only instrument at present used by anyone except
its own inventor is Lrvincston’s radio-atmometer (10), which
obtains an approximate measurement of the effect of direct solar
radiation on evaporation from a free water surface. Other methods
for the measurement of ecological factors have some local vogue,
but those here outlined are the ones most frequently used.

So widespread has been the practice of factor measurement, and
so many the workers, that a complete review of the literature would
be impossible in this connection, and in view of the extensive litera-
ture cited in such standard works as those of Livincston and
SHREVE (12), and of CLEMENTS (14), may well be omitted.

An important consideration in the development of a successional
series, but one that is not always given the prominence it deserves,
is the fact that the determining conditions that permit or bar the

1922] THONE—STARVED ROCK 347

entrance of new species in a given area are operative first on the
seedling. Liminal conditions act on the infant of the race, prac-
tically always. The operation of this principle may be seen in the
cultivation of adult plants outside of their natural habitats. These
often thrive, but do not produce offspring. By the simple law of
chance, propagules of all sorts are constantly falling into every area
within the range of flight or carriage from the parent, but only where
- conditions are such as to permit their germination and initial
growth do they become established. Once established they may
weather an unfavorable season, but they cannot gain a foothold
at all in a place where the conditions are unfavorable all the time.
This principle recognized, it becomes at once apparent that any
measurements undertaken with a view to their bearing upon suc-
cession should be made with special reference to seedling seasons
and places. The first worker to use this idea as a definite basis for
his investigations was FULLER (7), who made a study of the water
relations of several plant associations on and near the Indiana dunes.
His results indicated that the water supplying power of the soil was
fairly uniform, or at least adequate for growth, throughout the
season at all of his stations. On the other hand, the evaporating
power of the air varied markedly, showing a pronounced correlation
with the type of vegetation. The rate of evaporation bore an
inverse relation to the density of the vegetation, being greatest on
the cottonwood dune and least in the beech-maple forest. FULLER
concluded that the differences in evaporation rates were sufficient
to account for the successional range between the relative xero-
phytism of the cottonwood dune and the mesophytism of the
climax forest.
The present problem
TERRAIN

Conditions rivalling those of the dunes in diversity of vegeta-
tional associations to be found within narrowly restricted limits
exist in numerous steep-sided river gorges and their associated
canyons scattered across the whole Mississippi Valley, along the
edges of the various glacial drift areas, and in the unglaciated areas
adjoining them. These cliffs and canyons are invariably the

348 BOTANICAL GAZETTE [DECEMBER

habitats. of disjunct groups of various kinds: glacial relicts left
hind by the northern retreat of the first post-Pleistocene flora,
outliers from the mesophytic southeastern forests, forerunners of
western and southwestern plains, and desert types. This contact
of outposts of such different plant hosts is in itself an argument for
the existence of notably different environmental complexes in close
juxtaposition, and hence for the advantageousness of such locations
as critical points in the study of the physical factors of ecology.
The data for the present study were obtained at the Illinois.
State Park at Starved Rock, in La Salle County, Illinois. Here,
during early post-glacial times, the Illinois River cut a steep-sided
trench through the St. Peter sandstone (which at this point is thrust
to the surface by the La Salle anticline), and through its overlying
strata of Pottsville shales and clays and blanket of glacial till.
The geography of this region has been treated in detail by SAUER,
and the geology by Capy (6). The sides of the trench still remain
as lines of steep cliff, about a mile apart, facing each other across the
floodplain of the now much shrunken river. The cliff on the south
side of the river, from a point opposite the village of Utica eastward
for about seven miles, is unusually precipitous and high, reaching
a maximum of 157 feet from crest to mean low water level at the
Starved Rock itself. It is furthermore cut into by a series of remark-
able box canyons made by small tributary streams. Their sides
are as precipitous as those of the cliff itself, and for the most part
their bottoms are either at or near base level. Since the recession
of the river (which now washes the base of the cliff only in a few
limited spots, notably Starved Rock, Lovers’ Leap, and Pulpit
Rock) erosional débris has collected in places as talus slopes at the
foot of the cliff, both within and outside the canyons. In addition,
there are at the top of the cliffs the steep slopes from the top of the
sandstone caprock to the general level of the upland till, and at the
base a number of fragmentary river terraces of varying age, includ-
ing oxbows in various stages of filling, and finally the present juvenile
(and largely treeless) floodplain. A cross-section through a typical
location either over the cliff side or into a canyon, therefore, would
reveal the following types of terrain: (1) level upland of glacial
or Pottsville clay; (2) more or less steep slope toward the edge of

1922] _ THONE—STARVED ROCK 349

the sandstone cliff, also clayey; (3) exposed edge of cliff, sandy or
sand mixed with clay and shale; (4) precipitous cliff, usually with
weathered crevices and shelves; (5) talus slope, generally very
sandy, with much humus and some clay; (6) canyon bottom (allu-
vial), or river terrace — to sandy), or juvenile floodplain
(alluvial).

Veter rion

With so varied a terrain as that just outlined, presenting such
widely diverse types of habitat, it is only natural to expect a very
widely diversified vegetational development. This expectation is
well realized, for within the limits of the scant thousand acres of the
Starved Rock State Park there is a collection of plants that for
floristic and ecological interest can hardly be matched. All the
orthodox successional stages between Quercus macrocarpa of the
prairie edges and Q. velutina of the upland woods, to Q. bicolor of
the sloughs and the Populus-Salix thickets of the river edge are there
as a matter of course; but the region offers all the groups of dis-
juncts mentioned in a preceding paragraph as well. There are
places in this park where one can stand beside a white pine and
throw a stone through the top of a pawpaw!

No attempt can be made in this place even to outline the vege-
tational types to be found in this region. This has been presented
briefly by Cow.es (6), and a more detailed description by the present
writer is now in preparation. The present study concerns itself
more with the physical fagtors of the environment, especially as they
affect seedling growth and hence succession, in a number of typical
locations in the park. Ideally these determinations should have
been made in a considerable number of places, at least three for
each clearly distinguishable type of association, but this was beyond
the available resources in time and apparatus. In all, seven sta-
tions were maintained throughout the major portion of one growing
season, two on the upland, three on talus slopes, and two at the
bottom. In locating these, some diversity was possible, overcoming
in at least a slight degree the unavoidable inadequacy of data.
Stations 7 and 6 were located on the upland, no. 7 on the upland
proper, in a second growth Quercus velutina-Q. alba-Carya ovata
association, and no. 6 on a gentle slope from this toward the edge

350 BOTANICAL GAZETTE [DECEMBER

of the cliff (but away from the exposed sandy terrain), in a second
growth Quercus rubra-Q. alba association, with considerable under-
growth of Cornus, Viburnum, and seedlings of Prunus, etc. Sta-
tions 5, 3, and 2 were located on talus slopes, no. 5 about one-third
of the way down one, on the face of the cliff, and nos. 3 and 2 near
the tops of slopes on opposite sides of Hennepin Canyon. The
tree growth at station 5 was predominantly Quercus rubra, with
some Q. alba, Juglans cinerea, and Tilia americana, and a scattering
of other mesophytic hardwood species. The shrubby undergrowth
consisted mostly of Hamamelis virginiana, and the herbaceous situa-
tion was dominated by a magnificent ‘“‘fernery”’ of Osmunda clay-
toniana. ‘The soil here was a sand rich in humus, but with little
clay. Station 3, within the canyon, was on a rather newer slope,
the soil containing a considerable proportion of clay. The tree
growth consisted largely of Prunus serotina, and there was a dense
undergrowth of Psedera quinquefolia, Ribes cynosbati, Lonicera
Sullivantit, and Hydrangea arborescens. There was also a fair
development of mesophytic herbs. Station 2 was on a slope that
was newer still. The soil was sandier than on station 3, but raw
and poor in humus. It was full of stones, with large, moss-covered
rocks protruding. There were fewer trees, and these were mostly
young and small. A very considerable growth of Hamamelis
virginiana was present, but few other shrubs, and almost no herbs.
These three stations represented fairly well the state of the more
mesophytic talus slopes. Stations 4 and 1 were on representative
bottomlands, no. 4 being on the river floodplain and no. 1 on the
floor of the canyon. The soil in both places was a black alluvium.
The association at station 4 was dominated by Acer saccharinum
and Ulmus americana, with many seedlings and saplings. Other
undergrowth was mostly herbaceous, with Laportea canadensis,
Boehmeria cylindrica, and Campanula americana as the conspicuous
species. The alluvial floor of the canyon, where station 1 was
located, bore an association of Ulmus, with some admixture of
Juglans, Fraxinus, Populus, Salix, etc. Seedlings and young
trees were numerous, and there was a fair amount of undergrowth,
consisting largely of Sambucus canadensis, and at one place a notable

icket of Euonymus. There was an exceedingly rich, moist-

1922] THONE—STARVED ROCK 351

mesophytic herbaceous flora, typified by Impatiens pallida, Pilea
pumila, Campanula americana, and Lobelia syphilitica. Lianas
were abundant, more so than at station 4. In general, this was by
far the most mesophytic of all the stations. These three groups of
stations were thus fairly typical of upland, slope, and bottomland
respectively, and represented the principal plant associations reason-
ably well.

Instruments and methods

An effort was made at each station to secure some measurement
of each of the following physical factors: soil moisture, evaporating
power of the air, intensity of solar radiation (in terms of its effect on
evaporation from a free water surface), and temperature of soil and
air.

SoIL MOISTURE.—Soil moisture data were obtained by (1) the
usual determination of the oven-dry weight percentage in samples
of about 200 gm. each, compared with the wilting coefficients, as
derived by the indirect method of Briccs and SHANTz; and (2) the
“soil point”? method of Livincston and Koxetsv. All data were
obtained for a level of approximately 7.5 cm. below the soil surface.
This was the shallower of the two depths used by FULLER in his
dune studies, and represents the level at which most seedlings begin
their adventures. The soil points were used in sets of four, and
results recorded as the average, to eliminate as far as possible the
errors due to variability in instruments and soil. Holes were dug
to the proper depth with a trowel, care being taken that none of
them was within one-half meter of any hole in the same set or any
previous set. As a rule, soil from the holes into which the points
were set was taken for use in the moisture percentage determina-
tions. From April 30 until July 1 it was possible to visit the
stations only three or four times a month. From July 1 until
September 20 determinations were made every forty-eight hours,
except when rain intervened. -

EVAPORATING POWER OF AIR AND SUNLIGHT INTENSITY.—Data
on the evaporating power of the air and on the effect of direct solar
radiation on evaporation rate were obtained by means of a pair
of standard Livingston spherical atmometer cups at each station.

352 BOTANICAL GAZETTE [DECEMBER

These were equipped with the rainproofing valves described by
LrvincsTon and THONE (13). Their reservoir bottles were partly
buried, so that the cups were about 20 cm. above the ground level.
From April 30 until July 1 readings were made weekly or fort-
nightly, during the month of July they were made daily, and
from August 6 until September 20 they were made every two
days. All readings, after correction, were reduced to mean daily
rates for ten-day periods.

TEMPERATURE.—Air temperatures were obtained from a Sixe-
type minimax thermometer at each station. The thermometers
were placed at the same level as the atmometers. No artificial
shelter was used except at station 1, since there was sufficient natural
cover to protect the instruments from direct insolation at all the
other stations, and even at the latter place the growth of the
Impatiens thicket soon made artificial shelter unnecessary. Read-
ings were made on the same schedule as that used in the atmometer
observations. The stations were visited each day just before the
period of maximum temperature, so that the maxima and minima
for the preceding twenty-four or forty-eight hour period were
obtained.

Soil temperatures were obtained by means of test-tubes sunk
into the soil to a depth of 1ocm. The lower end was kept filled
with water, and the tube kept stoppered. When an observation
was to be made, a thermometer was lowered into the tube until the

b was immersed in the water, and read after sufficient time had
been allowed for an equilibrium to be reached. Since the readings
were always made shortly before the period of maximum air tempera-
ture,it may be assumed that the soil temperatures thus obtained were
a little below the maximum for the day. Since, however, the total
diurnal fluctuations in soil temperatures are known to be small,
and especially since in the present study they seemed in the end to
have no particular significance, this source of inaccuracy, as well as
the rather crude method employed for obtaining the data, may be
overlooked.

For both air and soil temperatures, it may be remarked that the
figures up to July 1 can have but little significance, since they apply
to periods of seven or fourteen days. During July, of course, true

1922] THONE—STARVED ROCK 353

diurnal data were obtained. From August 6 until September 20
readings were made every forty-eight hours.

Discussion

SOIL MOISTURE (figs. 1, 2).—It is obvious that topography can-
not affect the availability of soil water for plant growth until two
other factors have operated. The first of these, the amount and |
distribution of precipitation, is climatic, and thus affects all loca-
tions about equally. The second factor (or more properly group of
factors) is strictly edaphic, having to do with the effect of the
mechanical makeup of the soil (size, arrangement, and packing of
soil particles) upon the capacity of the soil to absorb and hold
precipitation water, and to deliver it to the roots of the plants
when they demand it. Finally, the topography is of importance in
its effect upon such factors as run-off, subsurface drainage, and
exposure to factors that influence evaporation, both from the
surface of the soil itself and through plant transpiration.

The -effects of the climatic factors are plainly evident in the
general conformity of all the curves in the soil moisture graphs, both
those representing the growth water (fig. 1) and those representing
the results of the operation of the Livingston-Koketsu soil points
(fig. 2). After the cessation of the spring rains in early June, and
until their resumption in early September, the season was one of the
hottest and driest summers on record in recent years. There was
but one brief period of precipitation, heavy rains occurring during
the first few days of August. The soil water percentages show a
notable correlation between the rainfall distribution and the water
content of the soil at all the stations. Beginning with moderate
but varying amounts during the late spring rains, all stations showed
a falling off throughout June, increasing in amount and rate of loss
through the July drought, and ending in a sudden increase at the
time of the early August rain. Following this was another sharp de-
crease throughout August, until a period of rains in early September
brought a rise, somewhat resembling, that of early August, but less in
amount. Fair weather during th period of the season
brought the beginning of another decrease. The ready responses
of the curve to both drought and rain are very notable features.

Fic.
stations, d

BOTANICAL GAZETTE [DECEMBER

TTT Prise lt rr oe
10 20 30 Ac

taal

=
10 20 30 Ac.
Toe reece es Cees eee es eee

.—Percentages of growth water present in soil at seven representative
uring ten-day periods from May 1 to September 20

1922] THONE—STARVED ROCK 355

LAAN AA EAAAL TEM Ae Ld 0a fae ek te
2 3G

AYW

Inn

AlN

isnonv

H38WI1d3$

| 2 3G
ee i OW bie we WEST et eH a a ae ee ee

Fic. 2.—Amount of absorption in gm. per two-hour period by Livingston-Koketsu
soil points at seven representative stations, during ten-day periods from May 1 to
September 20.

356 BOTANICAL GAZETTE [DECEMBER

The same fluctuation in the water-supplying power of the soil,
as shown by the Livingston-Koketsu soil points (fig. 2), is even
more marked. Both the individual determinations and their ten-
day means show fluctuations closely parallel to those of the growth
water percentage data. The close “bunching” of the ten-day
means during July and the period ending September 8 is especially
suggestive. Since the soil point method was devised in an effort
to determine directly the water-supplying power of any kind of soil,
independently of its wilting coefficient or any other physical con-
stant, this shows clearly that during such periods of drought all the
soils in the locations studied, save one, dropped to a very critical
water-delivering power. In the Livingston-Koketsu experiments
with wheat and Coleus under winter greenhouse conditions, perma-
nent wilting ensued when the water-delivering power of a soil had
fallen to a point between 0.04 and 0.11 gm. per two-hour period (as
compared with about 15.0 gm. for the same period in a nearly satu-
rated soil). The soil points used in the present determinations,
however, have a somewhat greater absorbing power. According to
data as yet unpublished, obtained by H. C. Dreut, the new points
have 1.25 times the absorptive power of those used by LIvINGSTON
and Koxetsu. The water-delivering power of the soil at the
permanent wilting point should therefore be between 0.05 and
0.14 gm. for a two-hour period. This is the case, at least, if we do
not take into account the evaporating power of the air at permanent
wilting. Since, however, the evaporating power of the air through-
out the droughty periods was greater at the stations considered than
it was in Lrvincston’s greenhouses, we are safe in doing so, and in
taking as an approximate water-supplying power at wilting point
0.15 gm. for the two-hour period. It will be seen that during the
drought periods all of the stations save one either approached or
passed this critical point, and that several of them were well beneath
it for a period of thirty days during July and one of twenty during
August, with an interval of only ten days between these two pro-
longed droughts. Further, a comparison with figs. 3 and 5
show that these were the periods of greatest stress from extremes of
temperature and evaporation. It is fairly evident, therefore, that
seedlings that are to survive throughout most of the park must be

1922] THONE—STARVED ROCK 357

of species able to get an early start or make sufficiently rapid
growth to have well established root systems before the advent of
the usual summer droughts.

A more detailed examination of individual stations serves to
emphasize the facts already noted in general, and also brings out
several edaphic phenomena of considerable interest. It is here
that topograph factors appear to function. Thus, station 1 is the
least exposed, and also the least well drained, being on the flat
floor of a canyon. It is also subject to flooding when there is
heavy rain, and the run-off from the tributary gullies comes over
the canyon falls. It is not surprising, therefore, to find that it is
constantly well above both the wilting coefficient and the Livingston-
Koketsu wilting point. It is not surprising, either, to find here the
largest number of young seedlings, and a herbaceous vegetation
dominated by annuals. On the other hand, the highest upland
station, no. 7, is both well drained and quite exposed; in correlation
therewith it rapidly loses what water it gains, and persistently
holds a place near the bottom of the column during the droughty
periods. Few seedlings develop, and the herbaceous vegetation
consists largely of grasses and sedges and of perennating prairie
plants. The stations on the more or less sloping terrain (no. 6 on
the upland and nos. 5, 3, and 2 on talus slopes) present phenomena
intermediate between these extremes.

Station 4, on an alluvial flat beside the river, in a maple-elm-ash
association, presents an anomalous situation. Starting in the
spring with a moderate amount of soil water, it loses rapidly and
fails to recover, during the summer rains, to anything like the
degree displayed by the other stations. The soil point data con-
firm its bankruptcy. After it has lost its water during June, it
falls to the bottom of the heap during the droughty periods and
stays there more persistently than any other station. During the
rains, when the others rapidly increased in their water-supplying
power, this station rose but little, and then quickly dropped to the
bottom again. This behavior may be accounted for in several
ways. The soil here is a heavy, silty alluvium, very tenacious of
the water it gets. It does not receive the benefit of periodic
flooding, as does station 1. The thicket of saplings is so dense that

358 BOTANICAL GAZETTE [DECEMBER

only the heaviest rains ever penetrate the foliage sufficiently to wet
more than the surface of the ground. A large proportion of the
soil surface is bare, puddling ‘easily, and thus facilitating direct
evaporation. These, and possibly other unnoted factors, can
account for the condition here.

EVAPORATING POWER OF AIR (fig. 3).—The effect of the climatic
factors that influenced soil moisture conditions is plainly evident
in the atmometric data also. There was more rainy and cloudy
weather during May than during June, and the rates of evaporation
show a corresponding decline during the latter month. Then, with
the beginning of the hot, dry weather of July the rates increased
suddenly and enormously. There was a sudden drop after the on-
coming of the early August rainy period. Throughout August the
daily temperatures were markedly lower than those for July (fig. 4),
with much cloudy weather, although actual precipitation was con-
fined to brief local showers; with this was correlated a reduction in
the transpiration curves to one-half or less of their July heights.
A short heated period at the beginning of September brought an
increase in the rate, but the ensuing cool, humid days that closed
the period of observation brought the curve down, and the season
came to an end with a period of very low transpiration rates.

A feature of some interest in the set of atmometric curves is
presented by the deep ‘‘dip” during the month of June. It was
natural that evaporation rates should be higher during July, as
already pointed out, but the sharp decrease from the May rates
seems at first somewhat anomalous. One possible reason suggests
itself in the comparative amounts of general exposure due to the
foliation of the trees. The spring of 1921 was late and cool, and
during May the trees, especially the oaks, were still nearly naked.
As the foliation increased, changes in three of the four main factors
controlling evaporation might naturally be expected; direct insola-
tion and air movement would be reduced, and relative humidity
probably increased. All of these changes would be in favor of
reduced evaporation. The fourth main factor, temperature, in-
creased somewhat during this time. This would have worked in the
opposite direction, but presumably the operation of the other three
had the greater effect.

1922] THONE—STARVED ROCK 359

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=
a
10 m2 25 cc
Pa See ee GE ees We RE ae ae Rae eee

Fic. 3.—Mean daily amounts of evaporation in cubic centimeters from standard
spherical black and white atmometers; cg columns indicate simple atmometric
irect insolation; a zero at

eltect; white extensions, increase rat
of column signifies data lacking ee the period.

360 BOTANICAL GAZETTE [DECEMBER

Mi T whe | z |

Uy Se i ee ee ee
!

; =
4 >
5 <
6

]

lho

‘ =
; a
6

2 =
i =
i =<
1

——

2
}3
3
16
}7

2 >
3 S
‘ és
g Ss
OO
1

=
J nm
He :
5 =
6

7 ——

| BG ak TE, Gs Ec Ra

Frc. 4.—Relative xerophytism (ratio of evaporation rate to growth water) at the
seven stations; a zero at base of column signifies data lacking for the period.

1922] THONE—STARVED ROCK 361

An examination of the differences between the curves of the sepa-
rate stations brings to light certain topographical correlations. In
the first place, there was a general correlation between the exposure
of a station and its evaporation rate. Thus, station 7, the most
exposed of the set, shows consistently the highest evaporation
rates, while station 1, the least exposed, shows consistently the
lowest. Even between these extremes the correlation holds, for
of the three talus slope stations, no. 5, the most exposed, shows
higher rates than nos. 3 and 2, which were partly sheltered within
the canyon.

Again, the more exposed stations showed much more marked
variation, both seasonal and diurnal, than did the more sheltered
stations. The highest mean daily rate for a ten-day period (26.9 cc.
per day, July 21-30) exceeded the lowest mean daily rate (8.1 cc. per
day, September 9-20) by 18.8 cc. This may be compared with the
excess of the maximum mean daily rate at station 1 (9.2 cc., July
21-30) over the minimum mean daily rate (1.3 cc., September 9-20),
which is 7.9 cc. The excess at station 7 is 10.9 cc. greater than the
excess at station 1, or a ratio of 2.4. Another notable thing is the
relative stability of the daily rates at the more sheltered stations as
compared with the greater fluctuation at the more exposed stations.
Thus, at the two stations and for the two periods noted, the greatest
mean daily rate at station 7 (26.9 cc.) exceeds the greatest mean
daily rate at station 1 (9.2 cc.) by 17.7 cc., whereas the least mean
daily rate at station 7 (8.1 cc.) exceeds the least mean daily rate at
station 1 (1.3 cc.) by only 6.8cc. The difference during the
period of highest evaporation rate is 2.6 times as great as the differ-
ence during the period of lowest evaporation rate. The general
effect of this factor is strikingly brought out by the “bunching”
of the curves during June and September, the low evaporation
periods. This greater variability displays itself even more mark-
edly, of course, in the diurnal variations than in the variations of
mean daily rates. During the period of high evaporation just
cited, for example, the readings at station 7 on three successive
days (July 14, 15, and 16) were 31.8 cc., 8.9 cc., and 19.1 Cc. respec-
tively, while on the same days readings at station 1 were 9.8 cc.,

362 BOTANICAL GAZETTE [DECEMBER

3.8 cc., and 10.4 cc. Similarly, even during a period of low evapora-
tion, three successive readings at station 7 give 15.3 CC., 5.5 CC.,
and 11.6 cc., while at station 1 the corresponding readings are 4.0 cc.,
1.4cc., and 1.8cc. Examination of the data from stations of
intermediate exposure will show correlated results.

The ratios between growth water and evaporation rates, pre-
sented in fig. 4, serve to emphasize and render definite the ideas in
the foregoing paragraphs. Of course, as FULLER (7) has pointed
out, this ratio is a more or less artificial and arbitrary one, yet it is
as good a method as we have at present for a quantitative statement
of the relative xerophytism of different habitats, and inasmuch as it
brings out strongly the cumulative effect of two factors operating
in the same direction, it is of value.

The foregoing considerations of the atmometric and soil moisture
data suggest strongly the essentially prairie-like summer conditions,
even in this woodland island in the prairie, and the intensification
of the summer xerophytism of the soil by the summer xerophytism
of the air. The greatest evaporating power of the air prevails
precisely during those periods when the plants are least able to
obtain water from the soil to satisfy it. Summer rains relieve the
tension, to be sure, but even after heavy rains the relief is short-
lived, and slighter in degree than might be supposed. Only in
places at once well endowed with a supply of water and at least
fairly well sheltered from extreme transpirational conditions (repre-
sented in the present study by station 1) is there any chance for
germination and growth of seedlings during the middle of the grow-
ing season. This theoretical conclusion is borne out by the existence
in such places of annuals as the dominant herbaceous vegetation,
and by the presence of large numbers of tree seedlings. Further-
more, it is here also that one finds “superclimax” trees, like Acer
saccharum and Asimina triloba, belonging normally to more meso-
phytic regions. In the more exposed stations (the extreme being
no. 7) the unfavorable summer conditions set in so early and become
so severe as to discourage seedling growth. The canyon bottoms
therefore receive strangers hospitably and permit of relatively a
succession, while the exposed uplands conservatively cling to
climax vegetation they have, and permit, in places too see

1922] THONE—STARVED ROCK 363

even for this, the survival of relict communities, like the conifers
on the edges of the cliffs.

INSOLATION EFFECTS.—An examination of the radio-atmometric
data serves to emphasize the atmometric phenomena already noted,
in addition to its main purpose of getting some idea of the sunlight
intensity as this affects evaporation. The evaporation from the
black cups of course follows the same general seasonal curve as that
from the white, the excess varying according to seasonal and local
conditions. The radio-atmometric effect, as one might expect,
was greatest during the season of greatest exposure, that is, during
the month of May, before the leaves were on the trees. After the
first of June the effect was much less marked. Even during the hot
weather of July the evaporation rate from the black cups exceeded
that from the white by but little.

The general differentiation in the radio-atmometric effect with
the development of the foliar screen was accentuated by local varia-
tions. Thus, the tendency throughout the season was for a greater
difference at station 7, the most exposed of the set, located in an
open stand of second growth oak. Station 1, located on a treeless
portion of the canyon bottom, in a stand of Impatiens pallida,
showed a most notable radio-atmometric effect during May, before
the surrounding herbage was well grown; after July 1 the effect
fell almost to zero, and remained so throughout the rest of the season.

Of course it is not possible to take the radio-atmometric effect as
a measure of solar radiation in all its effects on plants. It is intended
only as an approximate determination of direct solar radiation on
the evaporation of water from a free surface. Taking it as a rough
index of the total illumination received, however, we find that
during the season when other ecological factors are favorable for
the growth of seedlings on the forest floor it is at its maximum, and
that it falls off notably after the leafing out of the trees. Pre-
sumably then, sunlight conditions conspire with the ecological
factors already discussed to make late spring the optimum season
for seedling growth, and that at places like station 1, where other
conditions are favorable even when they are most unfavorable
elsewhere, sunlight intensity falls to an unfavorable level after
about July 1, or possibly even earlier. It must be emphasized again,

364 BOTANICAL GAZETTE [DECEMBER

however, that so little is known about the sunlight relations of
plants that attempts at close correlation are for the present un-
profitable.

TEMPERATURE (fig. 5).—Temperatures of both air and soil
show similar seasonal variations, with high points in July, and a
falling off in August and September, interrupted by a brief period of
high temperatures during the first few days of the latter month.
The figures up to July 1 can be accepted only as approximations,
since they are absolute maxima and minima for periods of more than
a week, instead of mean daily maxima and minima. For this reason
too much significance must not be attached to the greater spread
between maxima and minima. Although a greater spread did un-
doubtedly exist, it probably was not so great as the thermometer
readings at the ends of the periods would indicate.

So far as any significance may be attached to the figures before
the period of daily readings began, the influence of the diminution
of general exposure through the leafing of the trees seems to be at
work here also, for during May the maxima both for air and soil
show as marked a spread as that shown for the warmer months of
July and August. This spread is especially noticeable in the data
for soil maxima," inasmuch as it amounts to eight or ten degrees
throughout May, falls to a point at one of the June readings, and for
the rest of the season never exceeds three degrees. These results
agree fairly well with those of McDoucGa tt (14), who found a con-
sistent seasonal variation of about 4° F. between the soil tempera-
tures of typical upland and lowland stations in Illinois forests.

Topographical differences seem to have some influence also,
although the correlation is not so clear here as it is in the case of the
atmometric and radio-atmometric data. It may be remarked,
however, that the high lying stations (typified by no. 7) show the
highest maxima both for air and soil, and the low lying stations the
lowest maxima. On the other hand, the lowest minima for the
air are obtained at the high lying stations and the highest minima
at the lower ones. This may be due, among other things, to the
denser leaf covering and the greater amount of underbrush at the

* Because of the close agreement between the readings for all the stations after
July 1, it is not thought worth while to present the soil temperature data in detail.

1922] THONE—STARVED ROCK 365

YURUPETTIP PTT ry Tere err erp rere Pere eee ee he

10 20 30 40 50c

J
AVW

Inn

ANN

Isnony

te Suu «euewn— “ a -
NOUR we Surun. seNhun NA AL UNS MONK SAAS WN— SAAB HOR SON= NON SUN AWOHPENS SDURON= “HU eEN= WEUauUNn—

10 2 30 40 C

piliprittpilii Pei lite

Fic. 5.—Mean daily maximum and minimum air temperatures at the seven
stations; a zero at base of column signifies data lacking for the peri

366 BOTANICAL GAZETTE [DECEMBER

lower stations, holding the lower stratum of air to a certain extent
against displacement by air drainage.

One object in obtaining these temperature data was to ascer-
tain whether temperature differences might be correlated with the
invasion of lower latitude plants, like Asimina triloba, into the
lower levels. The data obtained, however, are contradictory. The
mean temperatures are undoubtedly higher at the higher lying sta-
tions, the last points of invasion, and also the last points of cession
by relict northern species. On the other hand, the consistent
higher minima at the lower levels might well permit a slightly longer
growing period, and perhaps even milder winter conditions. Other-
wise stated, the temperature optimum for southern species might
not be so nearly approximated on the lower stations as at the higher,
but a point above the minimum might be maintained throughout a
longer period each year. The main reason for the confinement of
southern invaders to the bottom lands, however, must probably be
sought in the more favorable moisture conditions at these levels.
The writer does not feel that attempts at close correlations between
temperature and vegetation over such small differences in altitude
would be very profitable at the present stage of development in
ecological science. It is interesting to find, however, that fairly
consistent small differences in temperature do coexist with small
topographical differences.

Summary

1. This paper is a study of the ecological factors at seven repre-
sentative topographical points in the Illinois State Park at Starved
Rock, during the growing season of 1921. The factors studied were
(a) soil moisture, (6) evaporating power of the air, (c) evaporating
power of solar radiation, and (d) temperature of air and soil.

2. Observations were taken with special reference to their
influence on seedling growth, because of the importance of the latter
as a factor in succession,

3. Soil moisture was found to vary (a) seasonally, falling off
after the close of the spring rains and reaching a point below the
minimum necessary for plant growth during a considerable portion

1922] THONE—STARVED ROCK 367

of the summer, and rising again with the beginning of the fall
rains; (6) according to the mechanical composition (and therefore
retentivity) of the soil; (c) to a minor extent according to topog-
raphy; and (d) according to the density of the foliage canopy.

4. The evaporating power of the air was found to vary (a)
seasonally, increasing until midsummer and falling off afterward;
(5) according to the state of tree foliation, declining after the forest
had become completely clothed; and (c) topographically, being
greatest for the same period in exposed stations and least in sheltered
ones.

5. The evaporating power of solar radiation was found to vary in
the same manner as the evaporating power of the air, complement-
ing and emphasizing the data under the latter head.

6. Maximum temperatures were found to vary in much the
same manner as the evaporating power of the air. Minimum
temperatures of the air were found to be affected by topography
in a mode inverse to that of the maxima, being highest at the low
lying stations and lowest at the higher lying ones.

7. Certain vegetational phenomena showed a general correla-
tion with the instrumental observations: (a) the density of ground
cover, number of tree seedlings, and proportion of annuals in the
total vegetation of any given association bore an inverse relation to
the relative xerophytism; (bd) in all but one of the stations, condi-
tions were favorable for the development of seedlings only in spring
and fall; (c) in the climax forest for the region (upland oak woods)
the water-supplying power of the soil consistently fell nearly or
quite to zero during the summer drought period; (d) the location of
“subclimax” and ‘“‘superclimax” associations showed closer corre-
lation with water relations than with temperature.

The writer owes a debt of special gratitude to Professors H. C.
Cowtes and G. D. Futter of the University of Chicago for their
encouragement and assistance in the preparation of the data here
presented. The courtesy of the Illinois State Park Commission
should also be acknowledged.

UNIVERSITY OF CHICAGO

368

w
ry

uw
.

BOTANICAL GAZETTE [DECEMBER

LITERATURE CITED

Atway, F. J., Studies on the non-available water of the — to the hygro-
scopic coefficient. Res. Bull. 3, Agric. Exp. Sta. Nebr.

. Briccs, L. J., and McLane, J. W., The moisture sollte of soils.

U.S. Dept. Agric., Bur. Soils, Bull. 45. 190

Briccs, L. J., and SHantz, H. L., The wilting coefficient for different
plants and its indirect Steitantion, U.S. Dep pune Bur. Plant Ind.,
Bull. 230. 1912; Bor. Gaz. 51:210-219. I911I; 53:20-27; 229-235. 1912.
Ciements, F. E., Plant ee an analysis of the development of
vegetation. Carmesie Inst. Wash., 242. 1916.

Cow Les, H. C., The ecological ie of the vegetation of the sand dunes
of Lake ‘Michioan. Bot. GAZ. 17:97-117; 169-202; 281-308; 361-391.
1899.

, Part III, Botany. In Saver, Capy, and Cowtes, Starved Rock
State Park and its environs. Geog. Soc. Chicago, Bull. 6. 1918.

. Futter, G. D., Evaporation and soil moisture in relation to the succession

of plant associations. Bor. Gaz. 53:193-234. 1914.

Livincston, B. E., Atmometry and the porous cup atmometer. Plant
World 18: 21-30; 51-74; 95-111; 143-159. I9I

, Atmospheric influence on evaporation and its direct measurement.
Monthly Weather Rev. 43:126-131. 1915.

, A radio-atmometer for measuring light intensity. Plant World
14:96-99. IQII.

Livincston, B. E., and Koxetsu, R., The water-supplying power of the
soil as related to the wilting of plants. Soil Science 9:469—-485. 1920.
Livincston, B. E., and SHREVE, F., The distribution of vegetation in the
United States as related to climatic conditions. Carnegie Inst. Wash.,
Publ. 284. 1921.

LivincsTon, B. E., and THONE, F., A simplified apie mounting
for porous porcelain atmometers. Science 52:85-87.

McDoueatt, W. B., A comparison of soil RUBE Hei, in upland and
bottomland forests. “vale: Ill. Acad. Sci. 13:249-254. 1920

tion of terrestrial animals and plants. National Geog. Mag. 6:229-238.

94. :
PuL.ine, H. E., Sunlight and its measurement. Plant World 22:151-171;
187-209. IgI9.

NOTES ON NEOTROPICAL ANT-PLANTS
I. CECROPIA ANGULATA, SP. NOV.
I. W. BAILEY
(WITH PLATE XV AND EIGHT FIGURES)
Introduction

In a previous paper (1) the writer discussed the significance of
the anatomical peculiarities of a number of Ethiopian ant-plants.
So many features of unusual interest were encountered in studying
these plants, that it seemed desirable to extend the scope of the
investigation, and to include certain neotropical myrmecophytes
for comparative purposes. With this end in view, the writer spent
the summer of 1920 at William Beebe’s Tropical Research Station
in British Guiana, where the following ant-plants (Tococa aristata
Benth., Triplaris surinamensis Cham., Tachigalia paniculata Aubl.,
Cordia nodosa Lam., and Cecropia angulata, sp. nov.) grow in close
proximity to the laboratory.

Since the publication of Scuimprr’s (8) much quoted investiga-
tions, Cecropia adenopus Mart. has been considered one of the most
classical illustrations of myrmecophytism. ScHIMPER interpreted
the ‘“‘Miillerian food bodies” and the ‘“‘prostomata”’ of this ant-
plant as adaptations for enlisting the services of an aggressive army
of Aztecas, which protect their host against the attacks of the
destructive, leaf cutting, Attine ants; a conclusion that has been
assailed by von InerInG (4), ULE (9), Retric (7), Fresric (3),
and other critics of the BeLt-pELPiNO theory of myrmecophily.
In view of the important réle that has been assigned to C. adenopus,
in discussions concerning the significance of ant-plant symbioses,
the writer welcomed the opportunity of studying a somewhat similar
species of this interesting genus. The results of the investigation
are summarized in the following pages.

Taxonomy

One of the first difficulties encounted in studying a neotropical
bioccenose, in which representatives ofthe higher plants, ants,
369] [Botanical Gazette, vol. 74

370 BOTANICAL GAZETTE [DECEMBER

coccids, and other insects are closely associated, is the identifica-
tion of the organisms concerned in the complex. Of course, the
principle of significant figures must be considered in biology, as in
physics and mathematics. The most detailed field observations
and carefully planned experiments may lose much of their signifi-
cance if an investigator fails to secure adequate information con-
cerning the identity of the plants and animals with which he is
working. In most cases, therefore, it is advisable to prepare
museum specimens which may be preserved as a record for verifica-
tion by other investigators. Typical herbarium specimens of all
of the plants to be discussed in this and in subsequent papers have
been deposited in the Gray Herbarium of Harvard University.
Specimens of the insects have been preserved in the collections of
Professor W. M. WHEELER, who collaborated with the writer in
the investigation of the myrmecophytes of the Kartabo region.
The ants were identified by him, the coccids by Mr. HAROLD
Morrison of the United States Bureau of Entomology, and certain
parasitic Hymenoptera by Professor C. T. BRUEs.

In dealing with Cecropia, one is concerned with a group of plants
which present many taxonomic difficultiés. The leaves of mature
plants frequently are much too large for herbarium sheets of
standard dimensions, and the inflorescences are difficult to season
for museum purposes. Thus many of the descriptions of species
are based upon the study of more or less fragmentary ‘material.
Furthermore, there appears to be as yet no consensus of opinion
as to which of the foliar and floral characters are of the greatest
diagnostic value. In view of these facts, the writer devoted
considerable attention to the investigation of the varia-
bility of the morphological characters of the Kartabo species of
Cecropia.

There proved to be two distinct species, a myrmecophytic
species, with a well developed trichilium and numerous food bodies,
and a non-myrmecophytic species, which is entirely devoid of
these structures. The latter is considered by Dr. E. H. SNETHLAGE
to be a variety (decurrens) of C. sciadophylla Mart. The former
does not agree with any previously described species, and owing
to its association with ants, was studied more intensively.

1922] BAILEY—ANT-PLANTS 371

During the earlier juvenile stages the leaves of this species are
small, +6 cm. long, + 2 cm. wide, simple, lanceolate, finely serrate,
pilose above and densely albido-tomentose below. The subse-
quently formed leaves increase rapidly in size, forming first three,
then five, and ultimately nine to eleven lobes (text figs. 1, 2).
As the juvenile leaves develop lobes, they lose their marginal serra-

Fic. 1.—Cecropia angulata: leaves from juvenile plants of different ages, showing
white tomentum and formation of lobed lamina; Xt.

tions and become sharply asperate upon the upper surface. The
transitions from the juvenile to the typical adult foliage are gradual,
and may be deferred until relatively late stages in the ontogeny
of the plant. Thus the large deeply lobed leaves of tall saplings
may retain many of the juvenile characters, that is, asperate upper
surface, chartaceous texture, conspicuous white tomentum on the
under surface, acuminate lobes, etc. The leaves of adult indi-

372 BOTANICAL GAZETTE [DECEMBER

viduals are huge, 56-98cm. long, 56-84 cm. wide, coriaceous,
glossy glabrous above, and are provided with only a microscopic
layer of closely appressed white hairs in the areoles of the lower

G. 2.—Cecropia angulaia: typical leaves from tall tree, showing variability in
size; Ce ~—Photograph by JoHn TEE-VAN

surface. They are divided to within 4-7 cm. of the base into 9-11
cuneate-obovate or spatulate lobes which have undulate margins
(text fig. 2).

Although at first sight most of the vegetative characters appear
to be extremely variable, many of them are relatively stable during

1922] BAILEY—ANT-PLANTS 373

specific stages in the ontogeny of the plant. For example, the
leaves of adult individuals always are deeply lobed and undulate
on the margins, never scabrous on the upper surface or conspicuously

Fig. 3.—Cecropia angulata: terminal shoot of tall, vigorous young tree, showing
8 tlie cae and foliar and florial bracts; X#4 —Photograph by Joun TEE-VAN.

tomentose below; whereas the leaves of juvenile plants always are
hairy or sharply asperate above, and are densely albido-tomentose
on the under surface. It is evident, therefore, that in distinguish-

374 BOTANICAL GAZETTE [DECEMBER

ing species of Cecropia it is essential to compare leaves from plants
of similar age classes, and, so far as possible, to avoid generaliza-
tions based upon highly variable, transitional types of foliage, such
as occur on saplings.

Fic. 4.—Cecropia angulata: terminal shoot of old, slow growing tree, showing ?
aments in different stages of development; X}*;.—Photograph by Joun TEE-VAN.

Certain of the floral characters are variable, whereas others
are relatively stable. The bracts which envelop the young inflor-
escences are coated during the later stages of their development
with dense, rufous tomentum, and are frosted with long white
chairs. The male and female aments (text figs. 3, 4) vary in size

1922] BAILEY—ANT-PLANTS 375

during different stages of their ontogeny, but the former (text
fig. 5A) retain their juvenile angularity, whereas the latter (text
fig. 6D) become nearly cylindrical at maturity. The peduncles
vary considerably in length, but are asperate in both sexes. The
female inflorescences are characterized by having one or more
perigones in the sutures between the short, stout, conferruminate

Fic. 5.—Cecropia angulata: A, cross-section of 6 ament, X2.5; B, surface view of
portion of 4 ament, showing pentenguias - cased Spay cleft perigee,
ro; C, é perigo hai
ber, X22; D, ee stamen of pair; EZ, upper stamen a same pair; F, upper stamen of
pair from another perigone; G, lower stamen of this pair; (D-G) X

pedicels (text fig. 7C). The clavate, pentangular or hexangular,
apically cleft male flowers are not jacketed by a dense mat of
long, interlacing trichomes, but are provided with a collar of short,
stiff hairs (text fig. 5). The perigonial chamber is confined to the
upper half of the flower, and the caudate anthers are borne on short
filaments which become extraordinarily broad and membranaceous
at the time of dehiscence (text fig. 5). The filaments, connectives,
and anthers vary considerably in size and shape (text fig. 5D-G);

376 BOTANICAL GAZETTE [DECEMBER

for example, the upper anther of each pair tends to be somewhat
smaller, and to be attached nearer its base to a longer filament.
The connective may or may not project beyond the apex of the
anther. The pentangular or hexangular perigones of the female
aments (text fig. 6) are characterized by having three distinct.
types of trichomes. They are jacketed both internally and exter-
nally by dense mats of long, interlacing hairs (text fig. 7). In addi-

Fic. 6.—Cecropia angulata: A, surface view of portion of 2 ament, showing
pentangular and hexangular perigones at fertilization, X10; B, surface view of por-
tion of 2 ament, showing enlargement of perigones during earlier stages in formation
of seed, X10; C, two types of trichomes from inner wall of perigone, 315; D, cross-
section of ¢ ament at fertilization, <2.5; E, trichomes from outer apical portion of
perigone (similar bristles occur on style); 315.

tion, they have a crown of extremely short, stout bristles on the
margins of their exposed apical surface, and a fringe of longer
bristles which project into the constricted upper portion of the
perigonial chamber (text fig. 6). The glabrous, almond-shaped
ovary is mottled, dark gray, and bears a cylindrical style which
terminates in a comose stigma (text fig. 7). The style is provided
with short, stout bristles, such as occur on the apical portion of
the perigone. During the development of the seed, the perigone

enlarges and becomes somewhat modified in form and structure
(text figs. 6, 7). The white tomentum is carried outward, so that
the lower two-thirds of the flowers are not held together by inter-

(Garber:

1,
whe

‘
s
es.

Fic, 7 -—Cecropia angulata: A, longitudinal section of 2 perigone and nearly
mature seed, showing embryo and various seed coats, X31; B, longitudinal section of
? perigone, style, ovary, and ovule, showing various types of trichomes, X31; C, basal
Portion of ¢ inflorescence, showing perigone at point of contact of conferruminate
pedicels, X4; D, ovary and style, X18; E, mature seed, X20.

lacing hairs, and an annular depression is formed in the exposed outer
surface of each perigone. At maturity the scurfy, dark reddish
brown, oblong seeds (text fig. 7£) have a more or less symmetrical,
lozenge-shaped, triangular or rectangular contour in cross-section.

378 BOTANICAL GAZETTE [DECEMBER

Owing to the variability of many of the floral characters during
the enlargement of the aments, there is a considerable element of
uncertainty in comparing inflorescences which are not in equivalent
stages of differentiation. In the case of the male aments, the
anthers, and especially the filaments, do not attain their most
characteristic size and shape until just before dehiscence. Further-
more, there are two distinct stages in the differentiation of the female
aments, one before and one after fertilization. The changes in the
size and form of the perigones during the maturation of the ovules,
and subsequently during the enlargement of the seeds, are reflected
in the aments, whose external characters become correspondingly
modified. The significance of these developmental stages does not
appear to have been appreciated fully by a number of students of
the species of Cecropia: The aments, perigones, stamens, seeds,
etc. are described and are used for diagnostic purposes without
reference to their variability or to their particular stage of develop-
ment. Until more is known concerning the variability of the
various species of Cecropia, and until their more stable diagnostic
characters have been isolated and fully described, it is desirable
to give rather comprehensive descriptions of new species. The
following description of the myrmecophytic species of the Kartabo
region is based upon the study of typical adult specimens. The
juvenile characters have been referred to previously.

Cecropia angulata, sp. nov.—Arbor 10-25 m. altus, caulibus
ramisque juvenibus argute asperatis formicosis (Azteca). Folia
ampla rubella vel viridia 56-98 cm. longa 56-84 cm. lata profunde
9-11-lobata, lobis cuneato-obovatis vel spatulatis, apice obtusis
vel rotundatis saepissime mucrontis, margine undulatis, lobo medio
36-60 cm. longo 13-24 cm. lato, nervis secundariis 15-20, lamina
supra glabra nitente (post exsiccationem castanea obscurata) infra
in nervis venis venulisque galbrata, in areolis solis tenuiter (micro-
scopice) albido araneoso-tomentosa et in disco centrali breviter
griseo-villosa, petiolo cylindrico (post exsiccationem costato) 50-
120 cm. longo glabro vel albido-tomentoso ad basin incrassato et
cum trichilio albido (tardius castaneo) instructo. Stipulae vagin-
antes maximae castaneae paullo griseo-tomentosae. Amentae 4
14-18 rectae rigidae angulatae 5-12 cm. longae 4-7 mm. crassae in

1922] BAILEY—ANT-PLANTS 379

pedicellis tenuibus 5-17 mm. longis gestae et in spatha castanea
griseo-tomentella fusiformi ad basin constricta 14-16 cm. longa
inclusae. Amentae 2 4 rectae rigidae vel apice paullo curvatae
cylindricae ante anthesin 9-12 cm. longae 7-8 mm. crassae (tardius
13-17 cm. longae 11-13 mm. diametro) in pedicellis crassis confer-
ruminatis 3-7 mm. longis gestae et in spatha castanea griseo-
tomentella quadrangulata obtusa 10-12 cm. longa inclusae. Ped-
unculi argute asperati compresso-cylindrici, $ 9-12 cm. longi 8-11
mm. crassi, ? 8-10 cm. longi 7-10 mm. crassi. Perigonia ¢ clavata
_pentangularia vel hexangularia 2-3 mm. longa, filamentis in maturi-
tate membranaceis 0.5-1.4 mm. longis 0.3—0.5 mm. latis, antheris
caudatis 0.8-1.0 mm. longis 0.4-0.5 mm. latis. Perigonia ? pen-
tangularia vel hexangularia cum albido tomento vestita ad anthesin
1.5-2.0 mm. longa deinde usque ad 3.0-3.5 mm. elongata. Stylus
cylindricus ovarium aequans vel eo longior. Stigmata comosa.
Fructus maturus furfurosus rubidus 2.0-2.5 mm. longus.

Kartabo region, British Guiana: J. W. Bailey (1920), nos. 3, 4, 5, 6, 8,
9, 14, 15, and 17; Kangaruma, British Guiana: H. A. Gleason (1921), no. 198.

The fistulose stems of Cecropia angulata are inhabited by four
distinct species of Azteca; a majority of the plants are colonized
by a black species, A. constructor Emery, a considerable number by
a yellowish species, A. alfaroi Emery, and an occasional isolated
individual by either A. imstabilis F. Smith or A. érigona subsp.
mediops Forel. The following observations upon the habits of
the guest ants are based upon a study of the first two species.

Of the coccids which are associated with Azteca, Pseudococcus
rotundus Morrison is the commonest species. Akermes quinquepori
Newstead and Pseudococcus bromeliae Bouché are of more or less
sporadic occurrence.

Are Cecropias protected by their guest ants?

In studying the remarkable leaf cutting and fungus growing
habits of the neotropical Attine ants, BELT (2) became much
impressed by the efficiency of these insects in defoliating large
numbers of native and introduced plants, and he was led to wonder
how tropical vegetation has survived their devastating attacks.
He inferred that the leaves of many plants are distasteful to the

380 BOTANICAL GAZETTE [DECEMBER

ants or are unsuitable for their purposes, and that other plants are
provided with special means of defense. He concluded that the
so-called bull’s-horn Acacias and other myrmecophytes are pro-
tected by their guest ants, which drive away their leaf cutting
relatives. MULLER (6) and ScuimpER (8) endeavored to prove
that the myrmecophytic species of Cecropia are protected by the
ants which inhabit their fistulose stems and branches. They found
that plants which were colonized by Aztecas were not molested by
Attine ants, whereas uninhabited individuals were more or less
completely defoliated by them.

That BELT, MULLER, and ScHmmPeEr tend, on the one hand, to ex-
aggerate the destructiveness of the leaf cutting ants, and on the other
hand to overemphasize the protection afforded by the guest ants, has
been suggested by von IHERING (4), RETTIG (7), ULE(9), FrEBRIG(3),
WHEELER (10), and other critics of the theory of myrmecophily.
Several of these investigators call attention to the fact, previously
noted by MOLLER (5), that the leaf cutting ants feed upon a great
variety of plants, and show no particular preference for the foliage
of Cecropia. Thus, although the Attine ants frequently are trouble-
some pests in gardens and orchards, their feeding habits under
normal conditions are such that they are not likely to exterminate
indigenous species. According to von IHERING’s computations,
183 nests of leaf cutting ants consume no more foliage during a
year than does a single cow. In many cases the myrmecophytes
grow in regions, such as swamps and periodically inundated areas,
where the fungus growing Attas do not occur. Furthermore,
during the earlier stages of its development Cecropia is not
inhabited or protected by its putative guardians. In addition, it
has been shown that plants which are not inhabited by Aztecas
may remain unmolested by Attas for long periods, and that trees
which are inhabited may be seriously injured by phytophagous
insects and sloths. Of course it must be admitted in this connec-
tion that the discrepancies between the conclusions of MULLER
and SCHIMPER and those of ULE, von ImERING, and others, may be
due to the fact that they were concerned with different species of
Attine ants. Furthermore, it may be argued that the juvenile

1922] BAILEY—ANT-PLANTS 381

plants do not need the protection of the Aztecas, since they are
immunized by various protective devices.

In the forests of the Kartabo region there are numerous colonies
of the common leaf cutting and fungus growing ant, Atta cepha-
lotes L. The writer found, as MOLLER had previously done in the
case of A. discigera Mayr., A. hystrix Latr., and A. coronata F abr.,
that this ant utilizes the leaves of a great variety of plants in the
construction of its fungus gardens. In virgin and second growth
forests, it seldom works for any considerable length of time upon
a particular type of plant, but continually shifts its activities from
one species to another. Owing to this fact and to the rapid recovery
from injury by plants in moist tropical environments, the effects
of its attacks upon a given species appear to be more or less evanes-
cent. Its normal leaf cutting habits, however, may be consider-
ably modified under unusual or abnormal conditions. It frequently
exhibits a strong preference for plants to which it has not previously
been accustomed. Thus its attacks upon certain exotic plants in
gardens and orchards at times may prove to be singularly persistent
and destructive.

In many cases Cecropia angulata is not colonized by its guest
ants until it has attained a considerable size. This is largely due
to the fact that the young, fecundated queens, which initiate the
new colonies, are killed by a Hymenopterous parasite, Conoaxima
_ astecicida Brues. Such plants are no more subject to defoliation
than are the inhabited individuals. In order to determine whether
the leaves of the juvenile Cecropia are distasteful to the leaf cutting
ants, or are unsuitable for their purposes, a number of young plants
were placed in close proximity to a large nest of Atta cephaloies.
Leaves of adult Cecropias and of various other plants were used as
controls. Although the ants worked upon this material in a more
or less sporadic fashion, and showed a strong preference for certain
types of leaves, they devoted no more attention to the mature
than to the juvenile foliage of Cecropia angulata. In view of the
fact that both Bett and ScuimpeER admit having seen young myrme-
cophytes defoliated by Attas, there appears to be little evidence
in favor of the suggestion that juvenile ant-plants are less suscept-

382 BOTANICAL GAZETTE [DECEMBER

ible to the attacks of phytophagous insects than are the adult
individuals,

In defending the theory of myrmecophily, ScHimpeR placed
great emphasis upon the discovery, in the Corcovado near Rio de
Janeiro, of a species of Cecropia which is devoid not only of ants,
but also of prostomata and Miillerian food bodies. He inferred
that this Cecropia possesses no adaptations for attracting a defend-
ing army of Aztecas, because it is protected by a waxy coating which
prevents the leaf cutting ants from climbing its stems. Cecropia
sciadophylla Mart. var. decurrens Snethlage is not colonized by
Aztecas, but, as will be shown later, is provided with conspicuous
and highly differentiated prostomata. The external surfaces of the
plant are scabrous and afford a firm foothold for ants, as evidenced
by the fact that several species of these insects were seen climbing
its stems and branches. This species of Cecropia is no more subject
to defoliation by Attas than is Cecropia angulata. That the leaves
may be utilized in the construction of fungus gardens is shown by
the fact that, when cuttings from plants of various ages are placed
near nests of Aita cephalotes, the ants frequently transport a portion
of the foliage into their subterranean dwellings.

SCHIMPER’S critics place considerable emphasis upon the fact
that the myrmecophytic Cecropias may be inhabited simultaneously
by two or more distinct genera of ants. To infer from this, however,
that the Aztecas are indifferent to the presence of other ants is
somewhat misleading. Although species of Cecropia were found
that were inhabited by Crypiocerus, Crematogaster, stingless bees,
etc., these insects were always confined to the older and lower
internodes, which had been abandoned by the Aztecas. In spite
of this marked segregation of the colonies in different levels of the
stem, fierce conflicts may be waged for possession of the intervening
internodes. Thus, the internodal cavities, where the colonies come
in contact, frequently are filled with the corpses of dead warriors.
The Aztecas are dominant, and in general do not tolerate the
presence of other ants, in those portions of the stems and branches
which are provided with leaves and food bodies. ScutmpER found
that when leaf cutting ants were deposited upon the terminal por-
tions of a Cecropia, they were quickly seized by the Aztecas, if.

1922] BAILEY—ANT-PLANTS 383

their presence was discovered, and were hurled to the ground.
How then may one account for the defoliation of trees which are
inhabited by Aztecas? When a Cecropia is touched or shaken,
the angry and aggressive Aztecas rush out of their nests and swarm
over the whole plant, but under normal conditions only a limited
number of workers are visible on the stems and bases of the petioles.
Furthermore, there are periods during which the entire colony is
quiescent, that is, has withdrawn into its nest. It is well known
that these periods of quiescence are not the same in the case of
different species of ants. Thus, certain ants are nocturnal, others
are active at temperatures when other species are inactive, etc.
In other words, as suggested by MtttER and MOLLER, a Cecropia
may be defoliated by leaf cutting ants during periods when the
Aztecas are quiescent.

Prostomata

Above the insertion of every leaf in Cecropia adenopus there is
a shallow groove, which terminates just below the next node in a
roundish depression (text fig. 8). As the external depression
corresponds to an internal one, the wall of the fistulose stem is
very thin at this place, and is a mere diaphragm ina tube. SCHIM-
PER showed that this diaphragm is devoid of hard and tough ele-
ments (fibrovascular bundles, collenchyma, lignified parenchyma,
etc.), such as occur in the adjoining portions of the stem. He
inferred from this that the diaphragm originated as an adaptation
for facilitating the entrance of ants. At the phylogenetic com-
mencement of symbiosis, the ants bored an entrance through the
groove, evidently because the wall of the stem was somewhat
thinner there. In accordance with a custom that is almost invari-
ably followed and is connected with the domestic arrangements in
their nests, they tended to penetrate into the internodal cavity at
its upper extremity (at the apex of the groove). All features which
facilitated their entrance at this place were retained in the struggle
for existence, and were accentuated through natural selection.
This led eventually to the differentiation of a thin, weak diaphragm
or prostoma (von IHERING). In other words, although SCHIMPER
admitted that the groove is due to the pressure of the axillary

384 BOTANICAL GAZETTE [DECEMBER

bud, he maintained that its terminal portion is a highly specialized
adaptation, acquired through the action of natural selection.
On the contrary, RETTIG and Fresric assert that the prostoma is
merely the youngest or less highly differentiated portion of the
groove, and that it is produced by the pressure of the axillary bud
and other growth phenomena in the elongating internodes. The
former investigator is of the opinion that the ants are deterred from
excavating in the lower portion of the groove, not by mechanical
obstructions, but by the occurrence of “‘laticiferous vessels’? which
are absent in the prostoma. It is to be emphasized in this connec-
tion, however, that Retric’s and Friesric’s statements do not
necessarily invalidate ScHimPER’s conclusion that the diaphragm
is an adaptation which originated as a modification of a previously
existing structure.

Under most growth conditions Cecropia angulata does not form
a shallow groove which terminates in a conspicuous circular pit
(text fig. 8). The more or less fusiform depression or rill is some-
what deeper in the upper than in the lower portions of the inter-
node, but the differentiation of specialized or mechanical types of
tissue is retarded throughout its extension (fig. 1). As the walls
of the internode increase in thickness, after the initiation of second-
ary growth, this fusiform diaphragm of delicate parenchyma is
slowly réenforced by tougher and denser tissues (fig. 3). The
metamorphosis begins at the base of the groove, and gradually
extends upward, but the ants excavate their exits before these
changes have progressed very far. It is evident, therefore, that in
the case of the myrmecophytic C. angulata, the whole groove is a
potential prostoma. The exact location of the aperture is deter-
mined, not by the presence or absence of resistant tissues or of
“Jatex”’ vessels, but by the relative thickness of different portions
of the diaphragm. That the whole groove is a potential prostoma,
and that the ants merely excavate their exits and entrances in its
thinnest and most easily perforable portion, are indicated by the
behavior of young queens in juvenile plants. In many instances,
several queens attempt to occupy the same internode, and as many
as five entrances were found cut at different levels of a single groove.
Not only do the queens cut through the basal portions of the
diaphragms under such conditions, but they may even excavate

1922] BAILEY—ANT-PLANTS 385

entrances in portions of the internodes which are not provided
with preformed depressions.

It may be argued that in C. angulata the whole groove has been
modified as an adaptation to ants. Such an assumption is not
warranted, however, when important facts in the anatomy of the
non-myrmecophytic C. sciadophylla var. decurrens are taken into con-
sideration. Although this species is not inhabited by Aztecas, it is
provided with more tenuous and highly specialized diaphragms than
is C. angulaia (text fig. 8; fig. 2). The internodal groove is very

Fic. 8.—Prostomata or internodal diaphragms of various species of Cecropia:
4,C. indenobus, after Scummper; B, C. sciadophylla var. decurrens; C,C. angulata; X4.

broad and deep, and the diaphragm, which is entirely devoid of
tough tissues and secretory vessels, is composed of extremely thin
layers of delicate parenchyma. Such facts as these suggest that
the so-called prostoma of C. adenopus, and of other myrmecophytic
species of Cecropia, is not an adaptation for attracting ants, but
is merely a structural peculiarity, produced by. the pressure of the
axillary bud, which is utilized by the ants in their parasitism upon
the plants

Feeding habits of guest ants

The Asteca colonies are initiated by young fecundated queens
which cut entrances into the fistulose stems of juvenile plants.
Although I examined hundreds of plantlets of C. angulata, none

386 BOTANICAL GAZETTE [DECEMBER

of any considerable size were found that had been entered by but
a single queen. The queens are so numerous that many of the
successive internodes become inhabited, and, as already stated,
one not infrequently finds that several queens have penetrated into
the same internodal cavity. So far as it was possible to determine,
however, a large proportion of these queens perish before they
have produced a brood. A very considerable number are killed
by the parasitic Conoaxima asztecicida, others are killed by their
rivals in conflicts for possession of a given internode, and, as soon
as the workers become numerous, they cut through the nodal
partitions and kill all but one of the surviving queens.

When a young Azteca queen enters an internodal chamber, she
covers the entrance aperture with a layer of triturated pith. The
entrance subsequently becomes occluded by callus, which continues
to grow internally, and finally projects some distance into the
medullary cavity (fig. 4). Thus the queen is sealed within the
internode during the period when she is initiating the new colony.
In view of the fact that the queen is unable to leave her nest in
search of food during a period of two months or more, MULLER,
VON IHERING, and Fresric infer that she must feed upon medullary
tissue and the inwardly projecting callus or ‘“‘stomatome.” It
should be noted in this connection, however, that such an assump-
tion is based upon two more or less fallacious premises: (1) that the
queen must feed during her period of isolation, and (2) that tissues
which are gnawed or excavated by ants actually are eaten by them.
Most students of the Formicidae are familiar with the fact that
female ants are able to do without food, except such as is stored in
their own bodies, for the greater part of a year, while they are
founding their colonies. Furthermore, it is well known that many
ants tend to gnaw into and smooth the walls of their nests, regard-
less of whether they are composed of living tissues or of inert
materials. I was unable to find any evidence that the Azteca queens
feed upon the tissues in the young internodes of C. angulata. The
so-called stomatomes, upon which MULLER and von InERING place
so much emphasis, are not uncovered and cut back by the queens
until just before the first workers are ready to emerge from the
nest, nor do they excavate the medullary tissue to any consider-

1922] BAILEY—ANT-PLANTS 387

able extent, except when in search of material with which to
block up the newly formed entrance aperture. Although von
THERING is of the opinion that the luxuriant growth of callus is
due to the stimulus of some substance excreted by the queens, I
found that homologous structures may be produced by purely
mechanical injuries.

With the advent of the first workers, the entrance to the pri-
mordial chamber is reopened, and the young colony either migrates
to a higher internode or cuts through the nodal partitions into
adjoining cavities. Von Inertnc states that the Aztecas always
abandon the primordial chamber and never perforate its upper and
lower walls. Such is not invariably the case in C. angulata, for
primordial chambers were frequently found in direct communica-
tion with internodes which were not provided with prostomal
openings. Regardless of its exact mode of origin, the permanent
domatium soon becomes stocked with food bodies by the young
workers. These small beadlike structures (fig. 6), which are packed
with fat and protein, are formed in large numbers in a curious
cushion or mat of hairs, situated at the base of each petiole. The
ripe food bodies are so assiduously collected by the ants that it is
almost impossible to find one in situ, except in young uninhabited
plants. Indeed, the ants frequently trim away the surrounding
hairs and dig out the immature food bodies. SCHIMPER interpreted
these so-called Miillerian corpuscles, and similar structures which
occur on the leaflets of certain myrmecophytic species of Acacia,
as metamorphosed glands or highly specialized allurements for
attracting ants. ReETTIG and others, however, have called atten-
tion to the fact that such glands occur on plants that are not fre-
quented by ants, and it is difficult for the adherents of myrmeco-
phily to account for such occurrences without resorting to the
purely gratuitous assumption that they are survivals from former
symbioses. ULE is of the opinion, in addition, that the expenditure
of carbohydrates and nitrogenous substances, contained in these
corpuscles, is not compensated for by the protection which the ants
afford to the plants.

Although most investigators agree that the food bodies are an
important item of food in the diet of the Aztecas, it has been

388 BOTANICAL GAZETTE . [DECEMBER

suggested that there are other potential sources of food in Cecropia.
Thus, vON [HERING and FIEBRIG maintain that the imagines feed
upon the succulent medullary tissues in immature internodes. It
is true that the ants cut away the softer portions of the pith down
to a hard, smooth peripheral layer of medullary tissue, but I found
no evidence to indicate that this is not purely a process of house
cleaning, such as occurs in many ant nests. In the moist, warm
interiors of plants, ants have to contend with luxuriant growths of
fungi which obstruct the cavities and interfere with the brood,
unless they are held in check. The ants trim away the hyphae
and cut back the substratum upon which these organisms tend to
grow. Fiepric records, having seen Aztecas busily engaged in
excavating the pith, and in casting fragments of medullary tissue
from their entrances, but such observations cannot be interpreted
as evidence that the ants actually feed upon the tissues that they
are removing.

Most students of the myrmecophytic species of Cecropia have
found coccids associated with the ants which inhabit the fistulose
stems. Their presence has been variously interpreted. BELT,
MU ter, and ULE consider that they are tended by the ants which
wee on their sugary exudations, but Freprie states that the insects

“in keinen direkten Verhiltnis zu diesen Ameisen stehen.”
Having found a very close and significant relation between ants and
coccids in most Ethiopian ant-plants, I devoted particular atten-
tion to the investigation of their behavior in C. angulata. I did
not succeed in finding a single large, ant-inhabited specimen which
did not contain numerous coccids. When a tree is split open the
ants are as solicitous for the welfare of the coccids as they are for
that of their eggs, larvae, and pupae. They seize them in their
mandibles and carry them about until some unopened portion of
the plant is found where they may be deposited in safety. In
artificial nests, the workers spend hours in tending and stroking the
coccids, and in feeding upon their sugary exudates. In view of
these facts, it cannot be doubted that the miniature milch cows are
an important source of liquid carbohydrates for the ants.

As in many of the African myrmecophytes, the ants excavate
pits in the walls of their domatia which enable the coccids to reach

1922] BAILEY—ANT-PLANTS 389

and feed upon the softer tissues of the Cecropia. Such excavations
are essential, owing to the fact that the internodal, medullary
cavity is entirely jacketed by a dense, horny layer of sclerenchyma.
In the African ant-plants, the ants cut through to the cambium and
induce the formation of a nutritive callus. In C. angulata the pits
are not located in the sides of the internodal chamber, but in the
nodal diaphragms. At the time when the ants begin their excava-
tions, the nodal partition consists of five distinct layers (figs. 5, 7).
The soft, internal layer, which is provided with strands of conducting
tissue and which is fed upon by the coccids, is separated from the
external layers of porous, medullary tissue by two layers of dense,
thick walled tissue. The ants remove the two external layers and
cut circular pits in the underlying sheets of horny sclerenchyma
(figs. 8,9). The coccids sit in these pits and thrust their setae into
the succulent tissue which is thus exposed. That the pits are not
made by the coccids, as suggested by von IHERING, is indicated,
not only by the fact the delicate sucking mouth parts of these
insects are not adapted for excavating in dense tissues, but also
by the fact that I have actually observed the ants in the process
of excavating them.

Summary and conclusions

The theory of myrmecophily, as modified by SCHIMPER, inter-
prets the structural peculiarities of myrmecophytic species of
Cecropia as adaptations for enlisting the services of an aggressive
army of Aztecas which protect their hosts against the attacks of
the leaf cutting Attine ants. Cleverly conceived and suggestive
as this Neo-Darwinian hypothesis undoubtedly is, it appears to
be based upon a series of plausible deductions or teleological infer-
ences, and is open to serious criticism. The distribution and feed-
ing habits of the Attine ants in luxuriant, tropical forests are such
that the ants are not likely to exterminate indigenous species.
They show no strong preference for the foliage of Cecropia, and
rarely attack either inhabited or uninhabited trees. Although
Aztecas tend to prevent other ants from visiting the terminal
portions of the adult Cecropias, they do not protect the juvenile
individuals. That the curious prostomata and Miillerian corpuscles

390 BOTANICAL GAZETTE [DECEMBER

of Cecropia adenopus and of other myrmecophytic species of Cecropia
are not allurements, acquired through natural selection, is indicated
by the fact that such structures occur on certain species of Cecropia
and other plants which are not frequented by ants. The Aszfeca-
Cecropia associations, and ant-plants in general, are extremely
interesting cases of parasitism, which illustrate the remarkable
adaptiveness of ants in availing themselves of the potentialities of
given environments. This is shown, not only in the utilization of
the preformed food bodies, prostomata, and internodal cavities,
but more strikingly in the structural modifications produced within
the plants for the growth and tending of coccids. Thus, the ants
are able to obtain food from the plant in two ways, fats and proteins
directly from the Miillerian corpuscles, and carbohydrates vicari-
ously through the coccids.

I wish to thank WiLL1aM BEEBE for numerous courtesies during
my visit to the Tropical Station of which he is in charge. To the
directors of the Gray Herbarium of Harvard University, the New :
York Botanical Garden, and the Berlin Museum, and to Dr.
Emit SNETHLAGE I am indebted for many helpful taxonomic data.
These investigations were conducted under a grant from the Ameri-
can Association for the Advancement of Science.

Bussey INSTITUTION
oREST Hitis, Mass,

LITERATURE CITED

1. Battey, I. W., The anatomy of certain plants from the Belgian Congo,
with special reference to myrmecophytism. Bull. Amer. Mus. Nat. Hist.
45:585-621. 1921-1922.

2. Bett, T., The naturalist in Nicaragua. London. pp. xvi+403. 1874.

3- Firsric, K., Cecropia peliata und ihr Verhaltnis zu Azteca alfari, zu ge
sexdens, und anderen Insekten, mit einer Notiz iiber sen aa
Acacia cavenia. Biol. Centralbl. 29:1-16; 33-55; 65-77.

4. HERING, H. von, Die Cecropien und ihre SPrhes iy Engler s Bot.
Jahrb. 39:666—714. 1907.

5. Moétter, A., Die Pilzgirten einiger siidamerikanischer Ameisen. Bot.
Mitteil. aus ies Tropen. Jena 6:pp. vi+127. 1893.

6. M@LLeR, Fritz, Die Imbauba und ihre Beschiitzer. Kosmos 8: 109-116.
1880-81.

PLATE XV

BOTANICAL GAZETTE, LXXIV

BAILEY on ANT-PLANT

1922] BAILEY—ANT-PLANTS 301

7. Rettic, E., Ameisenpflanzen-Pflanzenameisen. Beih. Bot. Centralbl. 17:
89-122. 1904.

8. Scoimper, A. F. W., Die Wechselbeziehungen zwischen Pflanzen und
Ameisen im ttopischen Amerika. Bot. Mitteil. aus den Tropen. Jena 1:
I-95. 1888.

. ULE, E., Ameisenpflanzen. Engler’s Bot. Jahrb. 37: - Fe 52. 1906.

‘ WHEELER, W.. M., Observations of the Central n Acacia ants.
Trans. 2d Congr. Entock Oxford (1912) 2: 109-139. 1913.

-
oo

EXPLANATION OF PLATE XV
Fic te, Ae angulata: cross-section of upper portion of internode,
showing prostoma”’; X10.
Fic. 2.—C. sciadophylla var. decurrens: cross-section of internode, showing
ti rwkoena?
Fic. 3.—C. angulata: capte-eecen of sa portion of internode, showing
formation of secondary wood in “prostoma’”’; X1
Fic. 4.—C. angulata: CrOME eNO of juvenile pint, showing occlusion of
entrance aperture by callus or “stomatome”’; X11
Fic. 5.—C. sciadophylla var. decurrens: ccubeacticn of nodal diaphragm,
showing ne layers of three distinct types of tissues; X18.
Fic. 6.—C. angulata: Portion of trichilium, showing food bodies and
pieces mat of hairs; X43.
Fic. 7.—C. angulata: cross-section of nodal diaphragm, showing layers of
thin daca parenchyma; XII
- 8.—C. angulata: Crh Weedon of nodal diaphragm, showing early
sage in spectrin of a pitlike excavation; X18.
G. 9.—C. angulata: cross-section of nodal diaphragm; soft external
lg of medullary tissue removed on both sides, and circular perforation cut
through horny layer on under side; X15.

PROTHALLIA OF LYCOPODIUM IN AMERICA
II. L. LUCIDULUM AND L. OBSCURUM
VAR. DENDROIDEUM
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 300
EARLE AUGUSTUS SPESSARD
(WITH PLATES XVI-XVIII)

In the first paper (4) there was included a short description
of a single prothallium of L. lucidulum; also reference to what was
thought at that time to be the prothallium of L. obscurum vat.
dendroideum. ‘The question raised then was later settled in a
short announcement published about a year later (5). It is the
purpose of the present paper to describe fully the hitherto unde-
scribed prothallia of these two species of Lycopodium, and to draw
such comparisons as may seem justifiable.

Material and methods

The method of collecting described in the first paper has been
followed almost entirely. It was found neither desirable nor
practicable to sift or to wash the soil. The smallest desirable
prothallia may be secured by the simple means of picking with
curved forceps. A patch of soil in the form of a square or rec-
tangle was removed to a depth of 4 or 5 cm., placed in a basket,
and carried to the laboratory, where the prothallia were picked out.
At frequent intervals small portions were placed under a dissecting
microscope for the detection of the very youngest stages. Lying
prone upon the ground is quite as good a method, save for the
fact that one gets extremely tired after four or five hours of painstak-
ing search.

For fixing, various mixtures of chromic-acetic-osmic acids were
used, as well as formalin-alcohol. While the former proved to be
somewhat better than the latter, it was not determined what is
the best mixture.

Botanical Gazette, vol. 74] [392

1922] SPESSARD—LYCOPODIUM 303

The prothallia of L. Jucidulum are ideal for a study of sex organs,
since they are long dorsiventral plants with the organs mixed and
growing acropetally from the apex. The main stages of both
organs have been secured in a single section. This is rather rare,
of course, but a comparatively few sections give one surprisingly
good results. Since they can be secured very easily in the field
because of their abundance, no other prothallia of Lycopodium offer
so many advantages at once for class demonstration and labora-
tory material as these.

Lycopodium lucidulum

Since the prothallium of this species of Lycopodium was not
known previous to my original brief description, it will not be out
of place to give a rather detailed account of it.

LOCALITY

Out of a total of more than 500 prothallia of L. lucidulum which
were found, only about half a dozen were gathered outside the
small region just north by several hundred yards of the Ridge
Street Cemetery at Marquette, Michigan. Evidence of the
existence of them was found at Mid-Island Point, Sugar Loaf
Peak, Negaunee, Munising, Ishpeming, and Michigamme. There
is no doubt that any region of the upper peninsula of Michigan
will yield prothallia, providing, of course, that it is in general a
habitat for the species. It is only because the present investiga-
tions were confined to a careful examination of a very limited
region that a larger range cannot be given here. This limitation
was made primarily to determine the relative abundance of material.

OCCURRENCE

This species of Lycopodium produces prothallia in remarkable
abundance. It is only necessary to become acquainted with the
habitat and to exercise a due amount of patience and vigilance, to
obtain a gratifying supply. All the prothallia were found within
an area not more than 25 m. square. Within this area there were
three especially rich patches, although these were not all discovered
the same season. One was found in May, another in September,
and the third in June of the following year. One patch measured

394 BOTANICAL GAZETTE [DECEMBER

I9cm.X16cm. and yielded 153 prothallia; another, measuring
18 cm. X14 cm., yielded 134 prothallia. The third patch was the
most yociadind being only 3cm. square, and containing 74
prothallia. In the two larger patches there were 178 sporelings
in all, 70 of which bore prothallia. Within the same general area
in which the three rich patches of prothallia were found, were five
other patches of the same general size, but which produced only
sporelings. No effort was made to count them, but they were more
numerous than the prothallia themselves, and were so closely
crowded that many of them failed to produce more than the first
set of leaves. In searching it was found to be much more profitable
to seek patches of abundant sporelings than to wander about look-
ing for isolated groups of them, even though these patches often
failed to produce any prothallia in spite of the great number of
sporelings. From this abundance of sporelings it is evident that
not infrequently prothallia occur in even greater quantities than
were actually secured from the richest patch found.

RELATIONSHIP TO SPORE-BEARING PLANTS

This investigation confirms the experiences of others who have
found prothallia of Lycopodium, namely, that they occur most
frequently where adult sporophytes are scarce. It seems probable
that this situation must be explained by some difference in the
soil. Since we know nothing of the conditions which govern the
germination and development of Lycopodium spores, so far as the
soil is concerned, a certain answer to the question is impossible.
I have observed, however, that the soil in which prothallia grow
is drier than that in which the adult sporophytes are found. This
is especially true for the species under consideration. It is certain
that an enormous number of spores must find their way to the soil
beneath the cone-bearing plants, but the latter grow so thickly that
sporelings would have little chance of survival, granting that
prothallia had succeeded in growing. The sickly condition of
many of the thickly growing sporelings found supports this idea.

As a matter of fact, prothallia do occasionally occur in even
the densest growths of adult sporophytes, and it is not improbable
that they might be found there in quantity. The fact that investi-

1922] SPESSARD—LYCOPODIUM 395

gators consistently fail to uncover prothallia with adult sporophytes
where the latter are growing thickly, in the opinion of the writer
does not negative the probability, for it is most tedious to hunt the
plants under these conditions. BRUCHMANN (1) has investigated
old areas of sporophytes probably more carefully than any other
investigator, but his method was first to remove the adult plants
and then to look for sporelings. In doing this the majority of them
would be destroyed. The writer has investigated the older plant
areas, both by the method of BRUCHMANN and without first remov-
ing the adults. Four prothallia were found by the latter method
and none by the former. Since the chief object was to secure
prothallia, the waste of time necessary to secure only a few speci-
mens among adult sporophytes caused the writer to abandon such
areas.

The question naturally arises as to how the adult plants of
L. lucidulum reach the habitats which are more moist than that of
the prothallia. Let us assume that a prothallium has succeeded
in growing on the side of a knoll or a hill, and that at the bottom
of this knoll or hill is a moister habitat favorable for the growth
of adult sporophytes. When the sporeling breaks through the
surface of the ground it faces the hazards of drought and too much
sunlight. If these are simultaneous or of sufficient duration, the
plant must surely die. The observations of the writer are that this
is a constant catastrophe in the struggle of these delicate plants.
Occasionally, however, we may expect to find a plant growing under
the conditions of a wet season. Then it progresses rapidly and
becomes a hardy specimen. When it becomes an adult it is capable
of producing spores and gemmae. It seems likely that it is the
gemmae that play the chief réle in further distribution, for when
small clusters of these adult plants are found they almost invariably
bear numerous gemmae, but rarely sporangia. When the gemmae
fall in habitats favorable for the growth of prothallia, they may
germinate well, and even form normal sporelings, but it is a sig-
nificant fact that they appear unhealthy and generally show the
incipient stages of extinction. On the other hand, those that reach
a moister region, like that at the bottom of our assumed knoll or
hill, grow vigorously.

3096 : BOTANICAL GAZETTE [DECEMBER

The line of distributive succession is not easily shown in L.
lucidulum, but a case of L. obscurum was found that well illustrates
the idea. A sporeling of this species was found that was 1o cm.
long, bearing six successive aerial branches and a distinct foot at
the end of the underground trailing stem. The sporeling grew on
the top of a small knoll, but instead of staying there, it took the |
shortest path toward the bottom, where adult sporophytes were
growing in a moist hollow.

The réle of prothallia in the life history of L. lucidulum is of
slight value to the species, therefore, once a colony is firmly estab-
lished. But for the opening up of new localities, and therefore for
the geographical distribution of the species, the gametophyte plays
the important part of getting a foothold in regions too unfavorable
for vegetative parts, especially gemmae, to flourish. The sporeling
itself rarely reaches maturity.

Two facts were observed in the collection of prothallia of various
species which seemed to indicate that some agent other than wind
takes part in the distribution of spores. The first of these was that
the prothallia, in nearly all species, occur in bunches. The second
was the frequent occurrence of prothallia in groups of four. The
latter condition is explained by supposing that the original group
of tetraspores was distributed bodily, and that the four germinated
simultaneously. This phenomenon was observed very frequently
in L. clavatum, L. complanatum, and L. lucidulum, most frequently
in the first.

At the time of the shedding of spores the tetrasporic group is
broken up, so that it does not seem probable that these groups are
distributed by the wind. The only other explanation which sug-
gests itself is that portions of the plant bearing sporangia are
carried away by animals. The appearance of patches of prothallia
and sporelings strongly suggests this. An isolated sporeling or
gametophyte is rarely found.

HABITAT

Many searches for prothallia have been futile, not so much
through a paucity of material as through a failure to learn, by a
process of elimination, the exact type of terrain in which they grow

1922] SPESSARD—LYCOPODIUM 307

most abundantly. It is difficult to describe what this is. In
general one must follow the same principles involved while search-
ing for the prothallia of any pteridophyte group.

For the prothallia of L. Jucidulum, moisture is without doubt
the most important factor. Countless millions of spores shed
annually from an acre of these plants fail to produce prothallia,
either because they are washed away into streams, driven too deeply
into the soil, lodged in water logged depressions, or are subjected
to dry conditions before and after germination. It is only when
they fall upon a region whose sandy substratum is covered by a
thin layer of leafmold, and is sufficiently protected from the seasonal
drought and from inundation, that they germinate and produce
prothallia. Such a place is a hillside or a hilltop with scattered
trees, very little shrubbery, and a scattered representation of such
herbs as the squawberry, wild sarsaparilla, Clintonia borealis, and
Polygala. Very often grasses and Polytrichum are found in such
a habitat. A sandy knoll with sparse vegetation and with a swamp
at its base is an excellent locality.

BRUCHMANN found many of his prothallia of L. Selago, a related
Species, in mats of moss. The writer found very few in such places.
The rich patches just described lay on a sandy hillside and were
protected only by the leaves which fell the previous autumn. The
soil was a rich humus for a depth of 1 cm., with almost pure sand
beneath. Although hundreds of sporelings were found, many
were in a desiccated condition, and only a very few would ever
have become adults, for adult plants habitually occur in regions
a little more moist than where the prothallia and sporelings were
found.

Because the prothallia of this species of Lycopodium were found
growing in such a variety of places, the following list of these may
be valuable: (1) in a hole at the base of a living birch tree; (2)
among the decayed needles of Pinus resinosa; (3) under a hard
maple tree; (4) on the top of a rotten stump; (5) on partly shaded
hillsides; (6) in the sand under a patch of Polytrichum and Polygala;
(7) in sand scarcely covered at all with humus; (8) in moldy humus
(most abundantly); (9) in muck, at the edge of a permanent pond;
(10) in the wheel tracks of an abandoned forest road.

398 BOTANICAL GAZETTE [DECEMBER

It might be well to add that the habitat of the prothallia of
this species of Lycopodium is somewhat more shaded, more moist,
and more protected from sunlight than that for L. clavatum, L.
complanatum, and L. annotinum. The prothallia of five species
have been found within a few centimeters of each other, however.
They are most abundant at a depth of 1 cm., and seldom grow at a
depth of more than 2cm. Very frequently they occur upon the
surface of the ground. The habitat of these prothallia agrees in
all essential respects with that for ZL. Selago, with the exception
already mentioned, which seems to indicate that they require a
slightly drier place for growth than do those of the latter.

DESCRIPTION

The older regions of the prothallia are brownish, while the
young growing tips as well as the very young prothallia are white.
It is these very white tips that are first noticeable when digging in
the soil. They are closely beset with multicellular hairs (fig. 49),
which in some cases include as many as five cells. They are evi-
dently of a glandular nature, for in fresh specimens of prothallia
the region which bears them is covered with a thin mucilaginous
secretion slightly denser than water. If the prothallia are placed
in water, this substance quickly swells and is dissolved. What-
ever its nature, no doubt it plays the important réle of keeping the
young growing region and the young sex organs from becoming dried.
None of the fungus filaments which closely adhere to the exterior
of other parts of the prothallium ever pierce it, nor do soil particles
or leaf mold adhere to it. It is probable that the growing apical
region is lubricated sufficiently by this substance to prevent injury
during its upward passage through the soil and mold, which are
often very compact and solid.

The adult prothallia vary very much in size and shape (cf.
figs. 2-41). These figures are all drawn to a scale of four, so that
they are just twice the size of the original specimens.

The form of the prothallium does not conform exactly to that
of any type heretofore described. It approaches nearest that of
L. Selago described by Brucumann. Taking fig. 15 as the type
form, it will be noticed that there is a lower cup-shaped primary

1922] SPESSARD—LYCOPODIUM 309

region, from which has developed a more or less dorsiventral
protuberance which becomes cylindrical near its apex only. In no
case were there found the two forms of body as described for
L. Selago, namely, the cylindrical or ‘‘ninepin” form and the
flattened form. All the specimens of the vertically growing pro-
thallia of L. lucidulum might roughly be considered as shaped
like a “ninepin” or an Indian club, but upon close examination
it has been found that sex organs grow only on one side, the rhizoids
opposite and lateral to them, and that the symmetry is distinctly
dorsiventral. It is only when active growth is taking place that
the apical region ever becomes cylindrical at all. Fig. 51 shows a
longitudinal section through the apex of a prothallium such as that
shown in figs. 15 or 49. This bilateral symmetry is present from
the very beginning of the differentiation from the meristem tissue.

If the prothallia grow upon the surface, however, they are dis-
tinctly of the L. clavaiwm or L. annotinum type (figs. 33, 35). Even
when growth continues after a subterranean prothallium has
reached the surface, this growth produces an expanded portion
which rests upon the ground (figs. 34, 37, 39). In other words,
when the length of the vertical portion is eliminated so that the
primary tubercle lies immediately beneath the prothallium, we
have a type in no essential respect different from that of L. anno-
tinum. Figs. 32 and 37 show prothallia semisurface and semi-
subterranean in development. In many instances (figs. 25, 28)
horizontal growth is solely below the surface, and it is not until
near maturity that the apical point turns abruptly vertical. In
such instances the prothallia are evidently of the L. annotinum
type originally, and later change.

In short, there are three methods of growth: one in which growth
is entirely vertical; one in which growth is first vertical, then
horizontal; and another in which growth is first horizontal and
then vertical. In several instances growth was originally vertical,
later assumed the horizontal, and still later resumed the vertical.

While a prothallium of ZL. Selago has never been examined, I
cannot see from the figures of BRUCHMANN any evidence of a typic-
ally “conical’’ or ‘‘ninepin” shape for that species of prothallium.
His fig. 32, plate VI, is the nearest approach to it, but the form is

400 BOTANICAL GAZETTE [DECEMBER

far from being typical, as the drawings to the left of it show. Even
in fig. 32 the sex organs occur on one side, while the vegetative
organs are mainly opposite and lateral to it. Apparently the only
difference between the form of the prothallia of the two species in
question is the alleged conical shape of L. Selago prothallia, and I
am not able to see that BRUCHMANN’s figures admit even of this
difference. If I were to use the same method of drawing as he has,
_ it would be almost impossible to distinguish between the typical
forms of prothallia of the two species. BRUCHMANN’S figs. 22, 28,
and 29 are especially easy to match with prothallia of L. lucidulum.
My figures merely accentuate the different regions of the prothallia,
while his suggest them.

For the present, therefore, the prothallium of L. lucidulum is
placed with BrucHMANN’s type for L. Selago, but it is probable
that the necessity for such a type is one of convenience rather than
a morphological one. For the sake of reducing the growing number
of types of prothallia for the genus Lycopodium, it might be well
to include these representatives of the L. Selago type in the L.
clavatum type.

Chlorophyll occurs regularly and abundantly in the subepidermal
cells of all prothallia of L. lucidulum which were found growing upon
the surface. Four prothallia were found which had bifurcated.
The age of the prothallia varied greatly, as the figures show. There
seems to be some evidence that the prothallia of L. lucidulum have
a much shorter period of development than BrucHMANN found for
his European species. Solely from field observations I should
estimate that adult prothallia for L. lucidulum probably mature
within two or three seasons, but the period for L. obscurum must be
much longer.

TISSUES

A longitudinal section of a prothallium like that shown in fig. 50
shows two main regions, an upper and a lower. The upper region
is divided into a distinct epidermis, which bears the sex organs and
paraphyses, and a subepidermal mass of cells of parenchymatous
structure which contain chlorophyll (when this is present) in its
upper half and reserve starch in the lower half. A cross-section
_is shown in fig. 64. This set of tissue, therefore, is reproductive

1922] SPESSARD—LYCOPODIUM 401

and assimilative in function, in its upper portion, while its lower
portion is employed for the storage of food material. The starch
grains are compound. While they occur most abundantly in the
lower half of the upper set of tissues, very frequently they are found
also in the cells immediately below the epidermis, in the venter
of the archegonium and the cells of the fungus regions (fig. 64).
Approximately the lower half of the prothallium is inhabited by
the endophytic fungus. This will be described later.

The meristematic tissue (figs. 51, 52) lies at the apical end of
the prothallium in a depression between the two groups of tissues
just named. A single apical cell is probably not present. Growth
is apparently brought about by periclinal and anticlinal division
of a small number of cells which form a meristematic plate between
the youngest portions of the upper and lower sets of tissues. The
mitotic figures of fig. 51 show that division continues in cells which
lie at a considerable depth. The lobed-like mass of tissue which
bends downward over the apical region and which bears the pri-
mordia and older cells of the sex organs is caused by this division
of the interior cells, as well as by the rapid division of the more
: superficial ones. The cells of the meristematic plate, from which
are cut off immediately the vegetative and reproductive primordia,
are filled with dense protoplasm and numerous oil drops (fig. 53).
_ Rhizoids.are very abundant, and are simple elongations of
epidermal cells on the lower side. No case was observed in which
a rhizoid was cut off by a cross wall.

SEX ORGANS

The prothallia are monoecious. The sex organs appear in
acropetal succession (fig. 51), the older ones being located (fig. 50)
in the tissue lying above the primary tubercle. Both antheridia
(figs. 54-58, 62) and archegonia (figs. 42-47) develop by the usual
stages known for the genus. The largest number of canal cells -
found was four. A double row of these was not observed. The
ventral canal cell is very much flattened at maturity. The egg
is slightly oval at maturity, with the long axis perpendicular to
the canal. It almost completely fills the venter. The neck of
the archegonium is short, and the venter lies completely below the

402 BOTANICAL GAZETTE [DECEMBER

level of the epidermis. The neck is not provided with a cover cell.
It opens by the dissolution of the inner walls of the four terminal
cells which border each other at a common line. As soon as fertiliza-
tion takes place further development of archegonia normally ceases.
Consequently two embryos on the same prothallium are rarely
found, and since fertilization occurs after the opening of the canal,
the embryo therefore lies very near the meristematic region. The
growth of the embryo causes activity there to stop, and as a result
it is found as a rule at the end of the prothallium.

Antheridia appear earlier and more abundantly than archegonia,
and are scattered throughout the entire upper surface of the pro-
thallium. They are circular or oval in outline, and may be sub-
merged entirely or may form a slight elevation on the upper part
of the prothallium. They are isolated and never form antheridial
masses similar to those very characteristic of L. obscurum to be
described later. Figs. 58 and 59 show the latter stages in the
development of the sperm.

The sex organ primordia lie so close together that it is impossible
always to say what kind of organ will develop. They may be
separated by a single layer of cells, or, as Miss Lyon (3) observed
in L. annotinum, they may touch one another. They are evidently
of such a primitive nature that it is impossible to distinguish an
antheridium from an archegonium in the very earliest stages of
their development. There are some indications that the arche-
gonial initial is slightly larger and longer than the antheridial initial,
but this is so uncertain that it is useless as a criterion.

As a result of this primitive condition, mixed sex organs are
very frequently found. These may be normally shaped antheridia
in which a few cells have never divided into sperm mother cells,
or they may be archegonial in form, the neck filled with normal
spermatogenous tissue, and the ventral canal and egg cells of
female appearance (fig. 60). The opposite condition may also
occur (fig, 61). Figs. 60 and 61 are sketches of two archegonia
constructed from camera drawings of nine sections in serial order.
Six abnormal organs of a bisexual nature were found on one pro-
thallium. They of course always occur near the apex of the pro-
thallium. The fact that sexual organs of a bisexual nature occur

1922] SPESSARD—LYCOPODIUM 403

on plants where primordia of sex organs are apparently alike in
position, suggests that we may be dealing with one of the primitive
stages of sex organ development. Ho.Lrerty (2) found the same
indifferent situation in Mnium cuspidatum. Miss Lyon brought
together considerable information on several genera of pteridophytes
regarding the condition in abnormal archegonia. A longitudinal
section is best for the study of sex organs.

Only the first division in the development of the prothallia
from the spore was observed. Fig. 1 illustrates the single specimen
which was found in field material.

Lycopodium obscurum dendroideum

The prothallia of this species were most difficult to find. The
sporelings have an appearance so much like those of L. complanatum
that a certain abnormally growing prothallium of the latter species
was described in my first paper (4) as that of L. obscurum. This
error was corrected as soon as discovered (5). A total of thirty-
seven prothallia were found. Twelve were dug up in a patch 2
feet square near the locality described for L. lucidulum, and very
near to a juniper bush. The others were found near Mid-Island
Point, Michigan. The exact spot lies just behind a row of cottages,
about 300 yards from Lake Superior and in an alder clump between
the lake and the marsh to the east of it. This spot was visited
first in July and later in August of 1917. It was very dry at this
time, but is probably water-logged for at least two months of the
year. Twenty-five prothallia of LZ. obscurum, fifteen of L. com-
planatum, and six of an undetermined variety of L. clavatum were
found in an area not more than ro feet square.

The soil in the first locality contained very little humus in the
sand. A species of grass and Polytrichum grew about the spot,
which was fully exposed to the sun, and no leaf mold was present.

e sand was yellowish a short distance below the surface, and
rather compact. The spot rests on a ridge about 15 feet higher
than the surrounding land. The lake bed once covered this point,
and it is probably an old sand bar.

The soil of the second locality could hardly offer,a more contrast-
ing condition as to physical appearance. The subsoil of course

404 BOTANICAL GAZETTE [DECEMBER

was sand, but this was covered by a soil mixture of half leaf mold
and half muck, covering lake sand. As a matter of fact, some of
it was nearly pure mycelial threads. Other parts were as hard as
dry muck itself. The prothallia found here grew for the most part
in the intensely moldy soil. Some were found at the border
between the humus layer and the sand lying beneath it. From
this it will be seen that one cannot name a type of soil as a criterion.

If it is desirable to indicate the type of place to look for Lycopo-
dium prothallia, I should say that one should look in neither the
dry nor the wet places. For my own part I search in those spots
a little less moist than the habitat of the adults. In the case of
L. obscurum and L. clavatum, very often the reverse is true, but
just as one cannot give a precise type of soil and moisture content
for the sporophytes, so he cannot for the gametophytes.

Sporelings were found in a variety of other places near Marquette
and Munising. The prothallia of ZL. obscurum probably grow
abundantly wherever the sporophyte has been known to exist for
a long time and in considerable quantity. Two prothallia and one
sporeling were found in July 1922, near Rhinelander, Wisconsin.
A sporeling and an old prothallium of L. complanatum were found
in June 1922, near Pembine, Wisconsin.

DESCRIPTION OF PROTHALLIA

The prothallia are of the L. annotinum type and not of the L.
complanatum type suggested in my first paper (4). They are about
as smooth as the L. annotinum prothallia, and never as wrinkled
or lobed as those of L. clavatwm. While the first are yellowish
brown and the second dark brown, those of L. obscurum are reddish
brown. They are also somewhat larger than those of the other
species. The largest one found measured 8X12 _mm.; the smallest
was about the size of a pin head. Figs. 65 to 71 show them just
twice the natural size. Owing to the fact that the rhizoids are so
few that the soil scarcely clings to them, they may be distinguished
by this means also. The young of the three species just mentioned
and L. complanatum cannot always be distinguished, but identity
of species can generally be determined by the habit of growth
of the endophytic fungus. Confusion of species is sometimes

1922] SPESSARD—LYCOPODIUM 405

unavoidable, however, and this is especially true when prothallia
of several kinds and of young age are found in the same lump of
soil. The writer discovered such a mistake after a four months’
study of a single slide. Certain features relative to the fungus were
found on it that did not occur in any of the other specimens to
which it purported to belong. In fact, it was this discrepancy that
led to the discovery of the mistaken identity of the prothallia under
discussion. The habit of growth of the endophytic fungus will be
discussed later. ;

Fig. 70 shows a specimen of ZL. obscurum which looks like
L. complanatum. The color and endophytic fungus both place it
with the species assigned. Furthermore, the remarkable habit of
growth of the antheridia was found present here, although the
drawing does not show it. The enlarged antheridial mass shown
in fig. 8: was taken from a specimen of a large L. complanatum
prothallium. Both were rotted away at the lower end. Now
_ no published figure of the last named species of prothallium shows
that antheridia grow in such enormous masses. These facts can
mean only one of two things, namely, that the fact of antheridial
mass growth has not been observed, or that the form of L. obscurum
prothallium is really intermediate between the L. complanatum and
L. annotinum types. In view of the fact that other observers of
L. complanatum prothallia were unlikely to overlook so conspicuous
a feature, I am inclined to the view that the prothallia of L. obscurum
occasionally take the intermediate position between the two well
known types. After careful examination of the specimens found
there is small likelihood of mistaken identity. If this be true, what
I have called a prothallium of L. obscurum in my first paper (4)
may need no modification. Moreover, the prothallia of L, Selago,
L. lucidulum, and the peculiar specimen of L. obscurum all show a
lateral groove more or less extensive, and are dorsiventral.

SEX ORGANS

The antheridia grow in enormous masses of white beadlike
knobs. These may half encircle the entire prothallium in the adult,
or may cause the very young to resemble cornucopiae. Such
structures have not been observed by the writer on any other pro-

406 BOTANICAL GAZETTE [DECEMBER

thallia with certainty. Certain prothallia previously figured (4)
seem to suggest them, but at that time prothallia of L. obscurum
were unknown, and identification was made upon comparison with
figures published by other writers. It is entirely possible that
those specimens may have been misnamed. There is also the
possibility that antheridia may occasionally take the form men-
tioned in species other than the one under discussion. Figs.
79-81 show the habit of growth of these organs. The prothallia
are all shown under a magnification of ten, so that a glance at the
figures will give the relative size of the individuals figured. Fig.
81 shows a mass enlarged.

A cross-section of the prothallium through two antheridial
ridges is shown in fig. 74. It is apparent that the masses arise from
the tissue lying within the outer border ring. For sake of clearness,
one region is represented as without the endophytic fungus. As a
matter of fact the fungus. does invade the antheridia through the
opening shown by the opercular cells in figs. 82 and 89. It has not
been located for certain in the cells of the antheridia walls, but it
is possible that the fungus is present in the intercellular spaces.
Because of the intimate relationship between the sperms, and
possibly the wall cells, with the fungus, it seems very likely that
the unusual growth of antheridial masses may be explained by
symbiosis. There is no indication of a pathological condition of
the sperms. The writer has never seen the fungus in the antheridia
of any other species of prothallia of Lycopodium. It is well known
that an endophytic fungus present in the prothallia of certain ferns
will cause abnormal growth of tissue.

The individual antheridia arise acropetally from the groove.
There is no primordium for the mass. This is a secondary growth,
although it arises very early. Figs. 87 and 88 show the antheridium
initial and the first division. The mature detail is shown in figs.
82 and 89. In this species four opercular cells may often be
observed. I have never seen it for certain in any other species.
The figures representing these cells were made by camera lucida.

In all of the prothallia sectioned, numerous retarded antheridia
were*observed. They were distributed throughout the older regions
of the plant, and had the ordinary appearance of the male organs,

1922] SPESSARD—LYCOPODIUM 407

but the mother cell walls were extremely weak and the nuclei small.
They appeared starved. The endophytic fungus was not demon-
strated to be present in them, and it is very probable that they
originated in the usual way.

Mitosis does not occur ituttebilals throughout the individual
antheridia. The organ is divided into quarters, and all the cells
of a single quarter will show the same phase, but one earlier or later
than the neighboring quarter.

ARCHEGONIA

The stages in the development of individual archegonia are the
same as those described for the genus. A few of the stages are
shown in figs. 83-86. The neck is rather long, containing as many
as fourteen canal cells. As a rule these are double, or at least part
of them are. Even the ventral cell is involved in this division
(fig. 86). In this organ the cells are beginning to disintegrate, as
shown by the swollen walls. The position of such an organ relative
to the prothallium is shown in fig. 90 on the cut edge. That the
doubling of the neck canal cells occurs early is shown by fig. 85.
One instance was observed of a very abnormal archegonial growth.
Six organs arose from the prothallium (fig. 90), which were all
apparently normal, near maturity, and about the same age. There
were traces of the endophytic fungus in the canals. The fungus
occurs normally in all the archegonia. It is probable that this
peculiar massing of archegonia is to be explained on the same
grounds as the antheridial masses. It would be instructive to
know how frequently this occurs. Unfortunately the mass was
not discovered until sections had been made, and the topographic
view had to be made up from serial sections.

The exact morphological position of the sex organs, especially
the antheridial masses, should be made plain. From a superficial
view of fig. 80, it might appear that the upper mass is derived from
the border, but the section shown in fig. 74 should make the matter
clear. It was rather difficult to determine the origin of the mass.
Antheridia of all ages are found in any one, but the primordia
always are found at the outer junction of the mass and the prothallial
tissue beneath. Nevertheless, certain sections showed that the

408 BOTANICAL GAZETTE [DECEMBER

primordia were slightly raised above the surface, as though dragged
there by rapid growth of the surrounding tissue. While I am
satisfied that there is no definite primordium for the mass, I am
not at all certain that the mass itself may not begin development
before the antheridial primordia appear; at least convincing evi-
dence was not found. If the fungus is responsible for the growth,
almost any order may be expected in the development of some
_ individual organs. It was not possible to be certain of the relation-
ship between the developing mass and the developing antheridia.
The organs are so numerous that only one of two things can occur,
either the whole group must spread itself, or most of the individuals
must be absorbed. There is conclusive evidence in the figures
that few are absorbed.

Endophytic fungus

The study of the endophytic fungus has delayed the publication
of this paper considerably. The following account refers to that
found in the two species of prothallia under discussion. Plate oo
has been added to show some of the structures observed. The
identity of the fungus has not been established. It does not appear
to be the same in both species. Both the reproductive structures
and the habit of growth support this statement. Furthermore,
there is evidence that they may both be Ascomycetes.

The illustrations are arranged so that the fungus of L. obscurum
is represented in the upper half of the plate (figs. 91-110), and that
of L. lucidulum in the lower half (figs. 111-126). Each group is
subdivided into reproductive and vegetative structures. No
attempt has been made to insure the morphological identity of
any structure represented. In the L. obscurum group, figs. 94-105
are supposedly reproductive structures, and figs. 106-110 vegeta-
tive. In the L. lucidulum group, figs. 113-117 and figs. 122-126
are supposedly reproductive, while figs. 118-121 are vegetative. The
structures shown in figs. 124 and 125 were found in both types of
prothallia. They are all shown under the same magnification, and
are collected from over 500 drawings.

All the reproductive structures, except in figs. 124-126, were
intracellular. The vegetative structures were intercellular. The

1922] SPESSARD—LYCOPODIUM 409

ascomycetous growth of fig. 124 was very common, but always was
found just outside the epidermis. It was found connected with
the intracellular mycelium, however. The mass shown in fig. 125
was often observed in decayed regions of the prothallia. Since
the ‘‘spores” shown in fig. 126 were found in such a mass, it is
probable that the fungus sometimes destroys the prothallium in
the older parts, to distribute its own spores. At any rate, many
prothallia of L. complanatum were found with the entire lower
half rotted away, and all the prothallia of L. obscurum sectioned,
and a few of L. lucidulum had rotten holes in them which were
filled with the fungus.

HABIT OF GROWTH

The fungus enters the prothallium either through the rhizoids
or between the epidermal cells. To say that it enters is not exactly
accurate. It may be possible to show that many of the “entering”
’ mycelia are in reality leaving the prothallium. It undoubtedly
gets a foothold during the earliest life of the plant. To within two
or three cells of the meristematic cells it is established (figs. 50, 51),
which shows that it is eminently capable of taking care of itself,
once it has obtained a foothold.

In L. lucidulum the fungus occupies the region shown in fig. 111,
but there is one peculiar thing to be noted. Only about half of
the cells contain the mycelial threads, the other half contain bodies
which in some respects resemble spores (fig. 112). These show no
nuclei under various stains. With safranin and aniline blue the
walls reacted like cellulose. In a few cases minute red chromatin-
like granules appeared differentiated, but these were never seen -
after iron alum haematoxylin; consequently, it is impossible to
state just what these bodies actually are. In a few instances very
minute mycelial threads were seen to radiate from pores in the
walls of these bodies, as though they were germinating spores.
These were always seen in section and cannot alone be considered
conclusive evidence that they are indeed such structures. So far
as this investigation goes, it cannot be said that they do or do not
have any relation to the endophytic fungus. They are such a
constant structure associated with the fungus, however, that some

410 BOTANICAL GAZETTE [DECEMBER

connection seems extremely probable. One other fact should be
noted. The obviously reproductive structures, found abundantly
in the cells which lie next to those containing the sporelike bodies,
are found without these sporelike bodies in the region neighboring
the meristematic tissue. In other words, the sporelike bodies are
not found in the cells which abut the meristematic cells. Since the
structures which looked like germinating spores and appeared to
contain chromatin also appeared in those very cells where the typical
sporelike bodies were wanting, the evidence is still stronger for the
spore interpretation. A few microchemical tests were made to
determine the exact nature of the cell wall of these bodies, but
nothing definite was established.

In L. obscurum the habit of growth of the fungus is markedly
different. The reproductive bodies are larger, and there are none
of the small sporelike bodies so persistent in L. lucidulum. All
the cells of the infected region contain the mycelium, but it is much
less extensive than in L. lucidulum (figs. 91, 93). Here there are
two lower cells with a very regular and tight coil of the mycelium,
which is much denser than shown in the illustration, where clear-
ness was desired. Above this layer is a region of finer coils, gener-
ally about one cell in thickness. The coils change their orienta-
tion slightly in the next layer above, until those of the uppermost
layer are at right angles to those of the lowest layers. The reason
for this is probably one of absorption, for the mycelial threads
finely divide and closely abut the walls of the palisade tissue which
lies above and which contains reserve starch. These fine threads
were never observed to enter the palisade cells, nor did their tips
show swelling. This very evident difference in habit constitutes
my first reason for believing that the fungus in the two species of
prothallia under discussion is not the same. The second reason
involves the reproductive-like structures. A glance at these struc-
tures at the top and bottom of the plate will reveal organs drawn
to the same scale, but vastly different in detail. The only possible
comparison may be found in figs. 97 and 125. The latter may be
only a later stage of the former. The lefthand cell of fig. 112
when compared with fig. 97 shows the contrast well. The organs.
of the last named figure occur only in the lower cells of fig. 93, but

1922] SPESSARD—LYCOPODIUM 4II

those of fig. 112 are equally distributed over the fungus region of
L. lucidulum.

In spite of these observations, there is another which needs to
be noted, and which may cast doubt upon them. The structures
shown in fig. 124 were found on the epidermis of both kinds of
prothallia, That shown in fig. 125 was never found except in the
decayed portions of both kinds of prothallia. I suspect that the
latter is only the maturer stage of the former. The ‘‘spores” of
fig. 126 were drawn from a ruptured heavy walled structure shown
in the lower lefthand corner of fig. 125. There were sixteen spores.
All these facts point to the ascomycetous nature of the fungus,
but since these last named structures were all found without the
epidermis or within decayed regions where external fungi would
have access, it is conceivable that they have no relation whatever
to the endophytic fungus. The internal mycelium was so constantly
segmented, however, that the Oomycete group has little chance
of being recognized.

While the evidence presented is in no respect conclusive, it
throws some doubt upon the Pythium theory as to the identity of
the endophytic fungus of Lycopodium prothallia. The writer dis-
likes very much to leave so important a question unsettled, but
it seemed best at least to record what had been observed.

Summary

1. The prothallia of two more species of Lycopodium have been
discovered.

2. The sex organs of L. lucidulum are primitive, being frequently
mixed in nature.

3. The prothallium of L. obscurum var. dendroideum shows a
form transitional between the L. annotinum and L. complanatum
spe

. The sex organs of the last named species are invaded by the
ihe fungus and consequently show deformities. The
antheridia and rarely the archegonia occur in enormous masses.

5. The sex organs develop individually as described for the
genus, and acropetally in the two species.

412 BOTANICAL GAZETTE [DECEMBER

6. The endophytic fungus is probably not Pythium. The
reproductive structures point to this genus, but the vegetative and
certain doubtful structures point to the Ascomycetes.

7. The habit of growth, and the appearance of the reproductive
structures, indicate that the same species of fungus is not present
in the two prothallia.

UNIVERSITY OF CHICAGO

LITERATURE CITED

1. BrucHMANN, H., Uber die Prothallien und die Keimpflanzen mehrerer
Europraischer Lycopodien. pp. 119. pls. 1-8. 18098.

2. Hotrerty, G. M., The development of the eaten acne of Mnium cuspi-
datum. Bot. Gaz. 37:106-126. pls. 5-6. 1

3. Lyon, FLORENCE, The evolution of the sex a of plants. Bor. GAz.
37: 280-293. 1904.

4. SPESSARD, E. A., Prothallia of Lycopodium in America. Bot GAZ. 63:
66-76. figs. 22. 1917.

, Prothallia of Lycopodium in America. Bor. Gaz. 65:362. 1917.

EXPLANATION OF PLATES XVI-XVIII
PLATE XVI. PROTHALLIA OF L. lucidulum

Fic. 1.—Germinating spore, with first wall transverse; found in field.

Fics. 2-41.—Habit sketches of various typical prothallia, some of which
bear sporelings attached; X 2.

Fics. 42-48.—Stages in development of archegonium; 375

Fic. 49.—Tip of prothallium, showing five antheridia thd ——
hairs.

Fic. 50.—Longitudinal section of prothallium.

Fic. 51.—Apex of same, showing acropetal succession of sex organs;
meristem plate of cells lies just behind first initial.

Fic. 52.—Detail of meristem and initial plate; 375.

Fic. 53.—Single cell from meristem region; 775.

Fics. 54-57, fig. 62.—Stages in development of antheridium and sperms;

375-
Fics. 58, 59.—Stages in sperm development; 775.
Fics. 60, 61.—Mixed sex organs, reconstructed from serial camera draw-
ings; X375«
Fic. 63.—Longitudinal section of embryo; X85.
Fic. 64.—Cross-section of prothallium, showing distribution of starch
grains.

PLATE XVI

BOTANICAL GAZETTE, LXXIV

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BOTANICAL GAZETTE, LXXIV

PLATE XVII

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SPESSARD on LYCOPODIUM

PLATE XVIII

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1922] SPESSARD—LYCOPODIUM 413

PLATE XVII. PROTHALLIA OF L. obscurum

Fics. 65-70.—Habit sketches of typical prothallia; <2.

Fic. 71.—Sporeling growing from prothallium which grew in inverted
position; natural size.

Fic. 72.—Germinating spore containing oil drops; X775.

Fros, 73-80.—Moderately young and mature prothallia in topographic
view; X10

Fic. 81 .—Antheridial mass enlarged, as seen when pressed out under
cover glass; X85.

Fic. 82.—Opercular cells of antheridium; 375.

Fics. 83-86.—Stages in development of PG ars.

Fics, 87-89.—Stages in antheridial development; 775.

Fic. 90.—Diagrammatic reconstruction of abnormal archegonial group,
constructed from serial camera drawings.

PLATE XVIII. ENDOPHYTIC FUNGUS
(All figs. <775 diameters, except figs. 91 and 111, which are X about 80.)
Endophytic fungus of L. obscurum

Fic. 91.—Distribution of fungus in prothallium.

Fic. 92.—-Two mycelial threads within rhizoid.

Fic. 93.—Three special layers of cells containing the fungus; mycelial
threads of upper layer applied closely to walls of starch-bearing cells; reproduc-
tive cells, when present, found only in two lower layers.

Fics. 94-105.—Intracellular reproductive structures.

Fic. 106.—Branch of intercellular mycelium leaving prothallium at base
of rhizoid.

Fic. 107.—Cross-section of a rhizoid containing six mycelial threads.

Fics. 108-110.—Intercellular vegetative structures.

Endophytic fungus of L. lucidulum

Fig. 111.—Distribution of fungus in prothallium,

Fic. 112.—Two neighboring cells; one at left contains mycelial threads
bearing reproductive structures, while other has no threads, but contains
numerous spherical sitet whose nature has not been determined.

Fics. 113-117.—Various reproductive structures, intracellular.

a IGS. Lads 23. — Vegetative heaabesiiorwies intercellular.

e found on epidermis of both species
of Babe iong but connected with ‘internal mycelium

Fic. 125.—Degenerated prothallia cells, with reproductive structures.

Fic. 126.—Sporelike bodies found several times in mass of fig. 125; sugges-
tive of ascospores

NEW SOUTH AMERICAN ASTERACEAE COLLECTED
BY E. W. D. HOLWAY
S. F. BLAKE
(WITH PLATE XIX)

The new species of Asteraceae here described form part of a
collection made by E. W. D. Hotway and Mrs. Mary M. HoLway
in Ecuador and Bolivia in 1920. A few have previously been found
by other collectors, notably by J. N. Rosr, who visited a part of
the same region in 1918. Although Professor Hotway’s interest
is primarily, in rusts rather than flowering plants, his appreciation
of the value of precise identification of host plants has resulted in
the preparation of complete and well dried specimens which have
considerably increased our knowledge of the phanerogamic flora of
the regions in which he has collected. Not the least valuable
result of his work in Central and South America is the discovery of
many new species of flowering plants, particularly Asteraceae,
represented by specimens far superior to those of many collectors
who confine their attention to phanerogams.

Achyrocline glandulosa, sp. nov.—Perhaps suffrutescent below,
40 cm. high and more, branched; branches ascending, simple, like
the stem densely glandular-pubescent, winged throughout by the
decurrent leaf bases, the wings herbaceous, 1-1.5 mm. wide; leaves
lanceolate or linear-lanceolate, 3.5-6 cm. long, 3.5-7 mm. wide,
acuminate, not narrowed at the long-decurrent base, entire, green
on both sides, densely glandular-puberulous, arachnoid-ciliate, tripli-
nerved; panicles rounded or flattish, 3-7 cm. wide, dense, the heads
densely glomerate on the branchlets, the glomerules at base loosely
pilose-tomentose like the branches of inflorescence; involucre
oblong-cylindric, 4-4.5 mm. high, whitish or pale straw color, the
phyllaries somewhat graduated, scarious, oblong or elliptic-ovate,
obtuse, glabrous; ? flowers 4 or 5, % 2; receptacle alveolate; % co-
rollas tubular-filiform, whitish, glabrous, 4-dentate, 3 mm. long,
the style included; % corollas slender, glabrous, 3 mm. long, 5-
toothed, the throat slightly ampliate above; achenes oval, glabrous,
Botanical Gazette, vol. 74] [414

1922] BLAKE—ASTERACEAE 415

0.7 mm. long; pappus 3 mm. long, the slender bristles denticulate
above, deciduous singly or in pairs.

Ecuapor.—Cuenca, September 10, 1920, Z. W. D. and M. M. Holway 982
(type in U.S. National Herbarium no. 1058640).

Allied to A. alata (H. B. K.) DC., which has fuscescent phyllaries and leaves
with long scattered hairs above. No reference is made in the description of
that species to the glands which are so abundant in A. glandulosa, and which
give it the fragrant odor of Gnaphalium obtusifolium.

Achyrocline hyperchlora, sp. nov.—Slender herb, 40 cm. high
and more, branching, the base not seen; stem and branches flexuous,
Wingless, stipitate-glandular and scantily arachnoid-tomentose,
glabrescent; leaves elliptic-lanceolate, 3-5.5 cm. long, 6-15 mm.
wide, acuminate or acute, cuneate into a petioliform margined
base decurrent for about 1mm., entire, membranaceous, tripli-
nerved, glandular on both sides, above green, pubescent with
several-celled hairs, loosely arachnoid, glabrescent, beneath per-
sistently griseous-arachnoid-pilose; panicles loose, much branched,
leafy bracted, the heads in small glomerules, involved in wool at
base; involucre 3mm. high, whitish faintly tinged with straw
color, the outermost phyllaries brownish toward base, the phylla-
ries oval to oblong, obtuse, scarious, stipitate-glandular and
lanate-pilose toward base; ? flowers 4, % 1; ? corollas whitish,
tubular-filiform, stipitate-glandular at apex, 1.8 mm. long; 4%
corollas similar but thicker, 5-dentate; achenes immature; pappus
2 mm. long.

Borrv1a.—Cochabamba, March 14, 1920, E. W. D. and M. M. Holway 406
(type in U.S. National Herbarium no. 1058598).

This species has the same sweet odor as A. glandulosa. It is of the A.
vargasiana group, and is distinguished especially by the character of its leaves
and its loose panicle.

Polymnia eurylepis, sp. nov.—‘‘Slender tree 4-5 m. high”;
branches stout, sulcate, densely hirsute-pilose with several-celled
sordid hairs and somewhat glandular-puberulous, glabrescent;
leaves opposite; petioles rather narrowly margined, densely pubes-
cent like the stem, 1-3.5 cm. long; blades broadly ovate or rhombic-
ovate, 7-19 cm. long, 4.5-11.5 cm. wide, acuminate, at base broadly
cuneate, then gradually cuneate to the base of the petiole, remotely

416 BOTANICAL GAZETTE [DECEMBER

denticulate (teeth minute, about 5mm. apart), submembranace-
ous, above densely glandular-puberulous along the nerves, essenti-
ally glabrous on surface, beneath duller green, evenly but not
densely hirsute-pilose, densely so along the veins and somewhat glan-
dular there, triplinerved above the base and loosely prominulous-
reticulate beneath, bullate in age above; heads 2 cm. wide, very
numerous in panicles 9-19 cm. wide; bracts ovate, 6-15 mm. long;
pedicels often decurved, glandular-puberulous and _hirsute-pilose
with several-celled hairs, 1-3.5 cm. long; disk subglobose, 6-8 mm.
high, 8-13 mm. wide; outer phyllaries 5, broadly ovate, acutish,
thin-herbaceous, ciliate, otherwise glabrous, 6-9 mm. long, 4.5-
6mm. wide; inner phyllaries (subtending the rays) oblong-oval,
obtuse, membranous, hirsute-pilose, 6mm. long; rays 12-14,
yellow, exceeding the involucre, the lamina oval, 7 mm. long, 3.5
mm. wide, the tube densely hirsute-pilose; disk corollas yellow,
sparsely hispid-pilose, 3.8 mm. long (tube 1.8 mm., throat broadly
campanulate, 1.5mm., teeth o.5mm.); pales acute, vittate,
sparsely hirsute-pilose dorsally, 3.5 mm. long; ray achenes obliquely
turbinate-subglobose, somewhat compressed, blackish, glabrous, 3
mm. long.

VENEZUELA.— Santo Domingo, altitude 2200 m., December 2, 1910, Alfredo
Jahn 128.

Ecuapor.— Along fences, Cuenca, September 10, 1920, EZ. W. D. and M. M.
Holway 974 (type in U.S. National Herbarium no. 1058639); Ficoa, near
Ambato, February 1919, A. Pachano 135.

his species is related to P. lehmannii Hieron., which has broadly margined
petioles, merely glandular-puberulous pedicels, sidllex outer phyllaries (5.5 by
1.75 mm.), which are puberulous at base, and 7-10 rays. It is also near P.
arborea Hieron., but in that species, represented in the National Herbarium
by fragments from the type, the somewhat larger outer phyllaries are densely
stipulate-glandular and sparsely hirsute-pilose on the back. Hotway’s label
gives the height of the plant as 12-15 ft. PacHAaNo calls it a ‘‘slender tree,”
and gives the vernacular name as “‘polaco”; JAHN gives the name “anime.”

Monopholis, gen. nov.—Shrubs with large alternate serrulate
or subentire leaves and many-headed terminal panicles of small pale
yellow cylindric heads; heads homogamous or heterogamous, the
disk flowers hermaphrodite, fertile, those of the ray when present
pistillate; involucre about 3-seriate, graduate, passing into the
pales, the phyllaries chiefly linear-elliptic or elliptic, indurated-

1922] BLAKE—ASTERACEAE 417

subherbaceous, appressed; receptacle small, convex; pales firm,
subindurate, persistent, all or the inner with thinner inflexed mar-
gins, more or less completely inclosing the achenes; ray corollas
usually none, when present solitary, ligulate, fertile, the lamina
oval, bidenticulate to trifid; disk corollas with slender tube, short
broadly campanulate throat, and 5 equal or longer reflexed teeth;
stamens with minutely sagittate base and ovate terminal append-
ages; style branches rather short, slightly recurved, with deltoid
obtuse papillose-hirsutulous tips; achenes linear-fusiform, narrowed
to the callous base, often shortly subrostrate, more or less com-
pressed, lenticular or trigonous in cross-section, wingless, glabrous;
pappus of a single usually broad deltoid to rhombic-lanceolate or
oblong paleaceous persistent awn borne on the inner side of the
achene, or rarely wanting.—Type species M. hexantha Blake.

A genus of four closely related species from the mountains of Ecuador and
Peru, related on the one hand to Verbesina, on the other to the imperfectly
known Monactis H. B. K. In habit and many other characters it makes a
rather close approach to the Andean species of the section Lreactinia of
Verbesina, but differs greatly in its linear-fusiform subrostrate wingless achene
with a pappus of a single broad paleaceous awn. Its relationship to Monactis
is closer, but the same characters of achene and pappus suffice to distinguish
it. The short, broadly campanulate corolla throat equaled or exceeded by the
spreading or reflexed teeth is also characteristic of Monopholis. The genus
may be inserted in the system next to Monactis.

In addition to the two species here described as new, two species described
by Hieronymus under Chaenocephalus but referable to this genus are repre-
sented by fragments in the National Herbarium. The following key will serve
to separate the species.

Heads chiefly pedicellate, the pedicels 1-7 mm. long.
Heads 6 or 7-flowered, 6-8 mm. high (excluding the corollas), 1.5—3 mm.

thick in fruit; involucre 3.5—4.5 mm. high; broader phyllaries 1-1.5 mm.

eh eek ee kee 1. M, hexantha
Heads about 12-flowered, 7-9 mm. high (excluding the corollas), 3-4 mm.
thick in fruit; involucre 5-6 mm. high; broader een” 1.8 to 2 mm.
WHEN re ee oes ce chert cysts . M. pallatangensis
Heads chiefly sessile, rarely short-pedicellate.
Branches loosely ee leaves broadly ovate; % flowers 8-11,
26: panpus Gh 3.9-5.6 Wim. long, 2. eos cc vin vs eres 3. M. holwayae
Hnaiches “densely cis imo: leaves lance-ovate or lanceolate;

% flowers 7 or 8, 2 I or 0; pappus awn o0.4-0.8 mm. long
4. M. jelskis

418 BOTANICAL GAZETTE [DECEMBER

1. Monopholis hexantha, sp. nov.—Shrub (or tree?); branches
flexuous, striate-angulate, 4mm. thick, obscurely griseous-
puberulous with matted hairs; branchlets of the year fuscous,
sordid-puberulous with loose several-celled subglandular hairs;
internodes 1-2 cm. long; leaves alternate, often with fascicles of
reduced leaves in their axils; petioles slender, naked, puberulous,
7-13 mm. long; blades lance-ovate or the smaller lanceolate, 6—
12 cm. long or more, 1.8—5.5 cm. wide, acuminate, at base acutely
cuneate into the petiole, serrulate (teeth depressed, less than 1 mm.
high, 2-4 mm. apart) or the smaller entire or subentire, pergamen-
taceous, above green, harshly tuberculate-hispidulous with mostly
deciduous hairs, beneath densely and softly griseous-tomentose-
pilosulous with crisped hairs and gland-dotted, triplinerved above
the base, bullate-rugulose above, prominulous-reticulate beneath;
panicles terminating the branchlets, many-headed, flattish or
rounded, 9-13 cm. wide, sordid-puberulous, the lower branches
subtended by reduced leaves, the upper bracts linear, minute;
pedicels 5 mm. long or usually less, often suppressed; heads dis-
coid, 6 or 7-flowered, cylindric, 6-8 mm. high, 1.5-3 mm. thick;
‘involucre graduate, about 3-seriate, 3.5-4.5 mm. high, passing
gradually into the receptacular pales, the phyllaries linear-oblong
to elliptic or sometimes elliptic-obovate, obtuse or rounded,
subherbaceous-indurated, greenish-white, sordid-ciliate, somewhat
glandular-puberulous, the outermost with narrow thinner some-
times purplish-tinged margins; corollas apparently pale yellow, the
tube sparsely pilose with several-celled hairs, 1.8 mm. long, the
throat broadly campanulate, glabrous, 0.8-1 mm. long, the 5 teeth
lance-ovate, acute, spreading or reflexed, glabrous, 1 mm. long;
pales linear-elliptic, obtuse, somewhat puberulous and ciliolate,
about 5 mm. long, similar to the inner phyllaries but longer, their
margins somewhat thinner, inflexed and inclosing the achenes, tri-
angular or rhombic in cross-section; achenes linear-fusiform, 3.5-
4-5 mm. long, 0.6 mm. wide, lenticular or trigonous in cross-section,
shortly subrostrate, blackish-brown, with callous whitish carpopod,
glabrous, finely papillose; pappus awn rhombic-lanceolate or oblong,
flat, acute or obtuse, usually sparsely denticulate, 1.2-1.6 mm. long,
about 0.3 mm. wide.

1922] BLAKE—ASTERACEAE 419

Ecuapor.—Cuenca, September 10, 1920, E. W. D. and M. M. Holway 973

(type in U.S. National Herbarium no. 105864
Monopholis pallat is(Hieron.) Blake.—Chaenocephalus
a teat Hieron. Bot. Jahrb. Engler 29:47. 1900.

Known only from the type collection made by Soprro (no. 38) in the
Pallatanga Valley, Ecuador. Fragments are in the U.S. National Herbarium.
Hieronymus describes the heads as 9 or ro-flowered, but I have found 12
flowers (all tubular) in each of two heads dissected.

3. Monopholis holwayae, sp. nov.—Branches stoutish, flexuous,
striate-ridged, sordid-puberulous with crisped hairs; internodes
2-5.5 cm. long; leaves alternate; petioles pubescent like the stem,
naked, 7-15 mm. long; blades ovate, 8-18 cm. long, 3-8 cm. wide,
acuminate, acutely cuneate into the petiole, remotely crenulate-
serrulate and somewhat repand or subentire, pergamentaceous,
above deep green, densely and harshly tuberculate-hispidulous,
along the veins sordid-puberulous, bullate in age, beneath rather
densely and softly griseous-pilosulous-tomentose and gland-dotted,
sordid-pilosulous along the chief veins, triplinerved above the base,
prominulous-reticulate beneath; panicles terminating the branch-
lets, flattish or convex, many-headed, 8~10.5 cm. wide, sordid-
puberulous with crisped subglandular hairs; pedicels usually
obsolete, sometimes up to 2mm. long; heads discoid, 8 to r1-
flowered, cylindric, 9-10 mm. high, 2.5-3.5 mm. thick; involucre
graduate, about 3-seriate, 4-5 mm. high, the phyllaries linear-
elliptic or the inner oblong, obtuse, subindurate below and with
thinner hyaline-subherbaceous greenish-yellow tip, sordid-ciliate,
sparsely glandular, passing into the pales of disk; corollas appar-
ently pale yellow, the tube sparsely long-pilose with several-celled
hairs, 2 mm. long, the broadly campanulate glabrous throat 1 mm.
long, the lance-ovate acute reflexed glabrous teeth 1.5 mm. long;
pales elliptic, obtuse, sordid-ciliate, dorsally sordid-pilose and
somewhat glandular, about 7mm. long, the inner with inflexed
margins more or less closely enveloping the achenes, the outer
flattish; achenes similar to those of M. hexantha but with more
acutely fas er base, 4.5 mm. long; pappus awn 1.3-1.5 mm. long.

Ecuapor.—Cuenca, September 15, 1920, E. W. D. and M. M. Holway 989

id ih in U. S. N ational Herbarium no. lpg nig
rs. Mary M. Hotway, who accom-

calla Professor Sesto on his South ce trip.

420 BOTANICAL GAZETTE [DECEMBER

4. Monopholis jelskii Hieron.) Blake—Chaenocephalus jelskit
Hieron. Bot. Jahrb. Engler 36:494. 1905.

Known only from the type collection by JELSKI (no. 698), made near
Tambillo, Peru, August 10, 1878. Fragments are in the U.S. National Herba-
rium. The pappus awn is rarely wanting in some of the flowers of a head, as
noted by Hrrronymus, but I have seen no case in which there was a second
shorter awn, such as he describes, present in the pappus. This appearance
may have been due to a splitting of the awn into two, the possibility of which
is indicated by the occasional occurrence of a deeply emarginate or bifid awn
in this or other species.

Wedelia holwayi, sp. nov.—Shrub, trichotomously branched;
branches slender, hispidulous and hispid hirsute with tuberculate-
based spreading or reflexed hairs 1 mm. long or Jess; leaves opposite;
petioles hirsute, 1-3 mm. long; blades lance-ovate, 3.5—6 cm. long,
I-2cm. wide, acuminate, cuneate at base, remotely serrulate
(teeth 4-10 pairs, 3-7 mm. apart), papery, above very harshly
tuberculate-hispidulous and tuberculate-hirsute, beneath equally
green, hirsutulous and hirsute, triplinerved, prominulous-reticulate
beneath; heads in threes at apex of stem and branches, 2-3 cm.
wide, on densely hispidulous and hirsute naked or 1-bracteate
peduncles 2-6 cm. long; disk 1-1.3 cm. high, 1.3-1.6 cm. thick;
involucre 3 or 4-seriate, graduate, 1-1.2 cm. high, the outermost
phyllaries obovate-oblong, herbaceous throughout or indurated at
base, acutish to obtuse, ciliate, tuberculate-glandular and sparsely
tuberculate-hirsute, 5-8 mm. long, 3-4 mm. wide, the innermost
elliptic-oblong or oblong with membranous-herbaceous ciliate
rounded tip, on back essentially glabrous, the middle series inter-
mediate in characters, all erect or with loose tips; rays about 12,
golden yellow, fertile, the lamina elliptic, 8-14 mm. long, 3-4 mm.
wide; disk corollas yellow, hispidulous toward base of throat, 6.5—-
7mm. long (tube 2—-2.5 mm.), the teeth papillose-hispidulous on
margin within; pales subscarious, obtuse or acute, spinulose-
denticulate above, 7-8 mm. long; ray achenes bluntly trigonous,
not winged or auriculate, sparsely pilose, their pappus cyathiform,
fimbriatulate, o.8 mm. long, with a partly free awn 1 mm. long on
the inner angle; disk achenes narrowly obovoid, thickened, densely
pilose, wingless, without ears above, 3.8mm. long, their pappus
cyathiform, narrow, 1 mm. high, lacerate-fimbriate, with 1 awn
1.5 mm. long.

1922] BLAKE—ASTERACEAE 421

Bottv1a.—Cochabamba, March 7, 1920, E. W. D. and M. M. Holway 376
(type in U.S. National Herbarium no. 1058597).

Nearest the Peruvian W. forbesii S. Moore, which has smaller lanceolate
leaves, longer peduncles, and shorter involucre and rays.

Wedelia isolepis, sp. nov.—Apparently suffrutescent, dichoto-
mously or trichotomously branched; stem and branches terete,
evenly but not densely spreading-hirsute with scarcely tuberculate-
based hairs 1 mm. long or less and somewhat puberulous, glabrate
or glabrescent; internodes 8-16 cm. long; leaves opposite; petioles
hirsute, 1.5-5 mm. long; blades ovate, 5~8cm. long, 2.53.8 cm.
wide, acute or acuminate, at base cuneate-rounded, remotely
crenate-serrate or crenate-serrulate (teeth depressed, 3-8 mm.
apart), papery, above deep green, harshly hispidulous and hirsute
(the larger hairs with persistent lepidote-tuberculate bases), beneath
paler green, evenly bat not conmged hirsutulous and along the veins
spreading-hirsute, tri ved above the b reticulate
beneath; heads in threes at apex of stem and branches, 3.5-4 cm.
wide, on naked densely hirsutulous and hirsute monocephalous
peduncles 1.8-9 cm. long; disk 1-1.2 cm. high, 1.5-1.8 cm. wide;
involucre 3-seriate, 1o-11 mm. high, equal or the innermost series
sometimes shorter, the two outer series of phyllaries equal, oval,
herbaceous throughout or somewhat indurated at base, obtuse,
rounded, or sometimes acutish, hirsute and minutely hirsutulous,
the innermost equal or shorter, with ciliate, purplish, membranace-
ous tips, dorsally glabrous, all often reflexed at tip; rays 12, golden
yellow, fertile, the lamina oval, tridentate, 15mm. long, 7 mm.
wide; disk corollas yellow, papillose-hispidulous on teeth, 6.5 mm.
long (tube 2mm.); pales acute, carinate, glabrous, yellowish and
spinulose-denticulate above, about 5 mm. long; disk achenes obo-
void, thickened, mottled, sparsely pilose, 3mm. long; pappus
cyathiform, o.5 mm. high, fimbriolate.

Botrvia.—Sorata, April 14, — E.W.D.and M. M. Holway 517 (type in
U.S. National Herbarium no, 105

Well distinguished by its teal characters.

Helianthus hypargyreus, sp. nov.—Evidently tall, herbaceous
at least above; stem stout, pithy, subterete, densely and softly
cinereous-pilosulous with reflexed or spreading hairs, glabrescent
or glabrate; internodes 2-13 cm. long; leaves alternate; petioles

422 BOTANICAL GAZETTE [DECEMBER

naked or margined above, those of the stem leaves 1-5 cm. long,
densely cinereous-pilosulous; stem leaves ovate or broadly ovate,
6-15 cm. long, 3—-8.5 cm. wide, acuminate, at base broadly rounded,
then shortly cuneate into the petiole, crenate-serrate above the
entire base (teeth 12-18 pairs, depressed-triangular, obtuse, 1-2 mm.
high, 2-5 mm. apart), thin-papery, above dull greenish, densely
and softly cinerescent-pilosulous with ascending hairs with small
tuberculate-subglandular bases, beneath very densely and softly
argenteous-pilose (sometimes yellowish-tinged) with subappressed
lucid hairs, triplinerved just above the base, the primary veins
evident beneath, the secondaries mostly concealed by the pubes-
cence; branch leaves smaller, sometimes subentire; heads 2-3 cm.
wide, in corymbose panicles of 3-9 at tips of branches and branch-
lets, the pedicels 1~5.5 cm. long, densely tomentulose-pilosulous;
disk depressed-subglobose, 8 to (fruit) 14 mm. high, 1.2 to (fruit)
1.8 cm. wide; involucre 3-seriate, graduate, 9-15 mm. high, the
phyllaries lanceolate or lance-elliptic to oblong-lanceolate, with
indurate vittate base and shorter or equal to (outermost) longer
reflexed or spreading acute herbaceous tips, densely sericeous- or
cinereous-pilose-tomentose outside above the sparsely pubescent
indurated base, the herbaceous apex densely pilosulous; receptacle
slightly convex; rays 12, golden yellow, neutral, the lamina hirsu-
tulous dorsally, elliptic-oblong or oval, 2 or 3-denticulate, 7-13 mm.
long, 3-5.5 mm. wide; disk corollas yellow, hirsutulous chiefly at
base of throat and on teeth, 5.5mm. long (tube 1.6 mm., teeth
o.8mm.); pales acute, carinate, hirsutulous at apex and very
sparsely along keel, about 8mm. long; achenes oblong-obovate,
strongly compressed, blackish, glabrous, 2.5—-3 mm. long, 1.2 mm.
wide; awns 2, subequal, deciduous, narrowly lance-subulate, his-
pidulous throughout, 2.5 mm. long; squamellae none.

Ecuapor.—Huigra, Province of Chimborazo, August 3, 1920, E. W. D.and
M. M. Holway 815 (type in U.S. National Herbarium no. 1058651); same
locality, August 18 and September 6, 1918, J. N. and G. Rose 22171 and
22568.

g This rather handsome species is related to H. imbaburensis and H. lehmannii
Hieron., both of which are now represented in the U.S. National Herbarium
by fragments from the types. The former differs in its narrower entire leaves
and much smaller heads, the latter in its black-purple disk and longer, acumi-
nate phyllaries.

1922] BLAKE—ASTERACEAE 423

Perymenium ecuadoricum, sp. nov.—Shrub(?); stem (above)
and branches herbaceous, 4mm. thick, harshly spreading- or
ascending-hispidulous, or sometimes strigillose; leaves opposite;
petioles naked, 7-20mm. long, tuberculate-strigillose, hirsute-
ciliate; blades ovate, 5—10.5 cm. long, 2.5—5 cm. wide, acuminate or
acute, at base truncate-rounded or rounded to cordate, crenate-
serrulate throughout (teeth about 32 pairs, obtuse, about 1 mm.
high), thick-papery, above deep green, bullate-rugulose, harshly
tuberculate-hispidulous, beneath densely and almost softly griseous-
hirsutulous-pilosulous and along the veins hirsute, triplinerved, the
veins and veinlets impressed above, densely prominulous-reticulate
beneath; peduncles ternately arranged, terminal and from the upper
axils, strigillose or erect-hirsutulous, 3.5-9.5 cm. long, bearing 2-4
heads on pedicels 1-5 cm. long, the bracts mostly very small, rarely
leaflike; heads 2.5-3 cm. wide; disk subglobose, 7-8 mm. high,
8-10 mm. thick; involucre 4-seriate, graduate, 7-8 mm. high, the
phyllaries broadly oval or the outermost oblong-ovate, with some-
what indurated base and shorter or subequal herbaceous or .
membranous-herbaceous rounded appressed tip, strigillose and
ciliate, the inner glabrous above on back; rays 12, golden yellow,
fertile, the lamina oblong-elliptic, 13mm. long, 4.5mm. wide;
disk corollas yellow, papillose-hispidulous on teeth, 4.8 mm. long;
pales obtuse to acute, minutely spinulose-denticulate on keel and
toward apex, about 4mm. long; disk achenes oblong, 2 mm. long,
somewhat thickened but compressed, transversely rugulose, sparsely
hispidulous above, often narrowly winged above on the inner side
and there produced into an ear about 0.5 mm. high, sometimes also
with a shorter tooth on the outer angle; pappus fragile, of about
ro unequal slender hispidulous awns 0.8 mm. long or less, and
I awn twice as long.

Ecvapor.—Huigra, Province of Chimborazo, August 3, 1920, Z. W. D. and
M. M. Holway 828 (type in U.S. National Herbarium no. 1058652); same
locality, August 18, 1918, J. N. and G. Rose 23820.

Closely related to the Peruvian P. jelskii (Hieron.) Blake (Wedelia jelskii
Hieron. Bot. Jahrb. Engler 36:488. 1905), of the type of which ample frag-
ments are now in the National Herbarium. In that species, however, the
leaves beneath are pale green rather than griseous, and much less densely
pubescent, and their petioles are only 4-7 mm. long, while the stem is rather
sparsely strigillose.

424 BOTANICAL GAZETTE [DECEMBER

Steiractinia rosei, sp. nov.—Shrub; stem stout, densely sordid-
pilose with matted erectish or loose hairs with small tuberculate
bases, glabrescent; leaves opposite; petioles pubescent like the
stem, naked, 7-17 mm. long; blades ovate or the smaller lance-
ovate, 8-14 cm. long, 3.5—-7 cm. wide, acuminate, at base cuneate-
rounded, closely crenate-serrate or crenate-serrulate with depressed
teeth, papery, above green, densely and harshly tuberculate-
hispidulous, along the chief veins sometimes densely pilose, beneath
rather softly and densely griseous-pilosulous or short-pilose, tripli-
nerved above the base, impressed-veined and somewhat bullate
above, prominulous-reticulate beneath; peduncles in threes at tip
of stem and branches, pubescent like the stem, 3-8 cm. long, bear-
ing 1 or sometimes 2 or 3 heads, usually naked; heads about 4 cm.
wide; disk depressed-subglobose, in flower 8-12 mm. high, 8-15 mm.
thick, in fruit 1.2-1.5 cm. high, 1.5—2 cm. thick; involucre about
4-seriate, graduate, 9 to (fruit) 15 mm. high, the outermost phylla-
ries suborbicular, herbaceous or with indurated base, acute or apicu-
late to obtuse, strigillose and somewhat strigose, 7-9 mm. long,
5-7 mm. wide, the middle ones very broadly obovate-oval, with
rounded ampliate submembranous loose upper portion, ciliate, on
back somewhat strigose or hirsute and strigillose, 8-11 mm. wide,
the innermost similar but smaller and shorter, often nearly glabrous;
rays 10, neutral, yellow, the lamina elliptic-oblong, when well
developed 2.5 cm. long, 8mm. wide; disk corollas yellow, 5.8 to
(in age) 7.8 mm. long (tube 1.5-2.8 mm., throat 3.5-4.2 mm., teeth
sparsely hispidulous near tip, papillose along margin within, o.8 mm.
long); pales narrow, acute, carinate, spinulose-denticulate above,
about 8mm. long; achenes obovate-oblong, compressed, blackish,
narrowly 2-winged, 3.8mm. long, sparsely hirsute-pilose, on the
wings hirsute-ciliate, slightly contracted at apex into a collar about
0.3 mm. high, this bearing the caducous pappus of about 30 slender
unequal hispidulous awns 3 mm. long or less.

Ecvuapor.—Huigra, Province of Chimborazo, August 4, 1920, E. W. D. and
M. M. Holway 832. Vicinity of Loja, September 29-October 3, 1918, J. NV.
Rose, A. Pachano, and G. Rose 23290 (type in U.S. National Herbarium no.
1023389).

Related to S. sodiroi (Hieron.) Blake, which has larger heads and outer
phyllaries rather abruptly contracted into an indurated base.

1922] BLAKE—ASTERACEAE 425

Verbesina adenobasis, sp. nov.—Shrubby (?); branches stout,
herbaceous, pithy, sordid-pilosulous with crisped hairs, glabrescent;
leaves opposite or subopposite; petioles sordid-pilosulous, marginate
above, stout, 1-2.5 cm. long; blades broadly ovate or rhombic-
ovate, 12-17cm. long, 7-10cm. wide, sometimes with a short
triangular lobe on one side near middle, acute, at base rounded-
cuneate, then cuneately decurrent on the upper part of the petiole,
serrulate above the base (teeth about 4o pairs, slender, acutish,
1mm. high), papery-pergamentaceous, above deep green, densely
scabrid-hispidulous with glandular-tuberculate-based hairs, very
densely so along the veins, beneath rather densely hirsutulous-
pilosulous with crisped somewhat deciduous sordid hairs (those
along the veins dense and brownish), triplinerved above the base,
loosely prominulous-reticulate beneath; panicle terminal, ter-
nately divided, very many-headed, flattish, about 22cm. wide,
densely sordid-pilosulous with several-celled crisped sordid sub-
glandular hairs; bracts minute; pedicels 3-14 mm. long, sometimes
obsolete, naked or with minute bractlets; heads narrowly becoming
broadly campanulate, the disk 8-11 mm. high, 3-4.5 mm. thick;
involucre about 3-seriate, graduate, about 4 mm. high, passing
into the pales, the outermost phyllaries small, linear-oblong or
spatulate-oblong, herbaceous, obtuse or rounded, glandular-
puberulous, ciliolate, 1.5-2 mm. long, 1 mm. wide or less, the inner
oblong, obtuse, 1-1.3mm. wide, ciliolate, otherwise glabrous,
greenish-white, all appressed; rays 2 or 3, pale yellow, fertile, the
lamina oval, 4.5 mm. long, 2.8 mm. wide; disk flowers 11 or 12,
their corollas pale yellow, pilose on tube with several-celled hairs,
5-5-6 mm. long (tube 1.5-2mm., throat cylindric-funnelform);
pales obtuse, glabrous or somewhat ciliolate, 6mm. long; ray
achenes trigonous, 3-awned; disk achenes obovate, very flat,
essentially glabrous, 5 mm. long, the body 1.5 mm. wide, 2-winged,
the wings o.5—o.9 mm. wide; awns 2, subequal, subterete, sparsely
hispidulous, 3.5—4 mm. long.

Ecuapor.—In shrubbery along roads, Cuenca, September 15, 1920, EZ. W.D.
and M.M. Holway 991 (type in U.S. National Herbarium no. 1058641).

A member of the V. arborea group, related to V. Woensis Hieron., which
has velvety-tomentose branches, oblong alternate leaves, 3-6 ray flowers or
none, and 12-18 disk flowers.

426 BOTANICAL GAZETTE [DECEMBER

Verbesina latisquama, sp. nov.—Shrub (?); branch stout, her-
baceous, pithy, striate-subangulate, sordid-pilosulous with crisped
hairs, glabrescent; leaves opposite; petioles stout, densely sordid-
pilosulous, marginate above, the naked part 7-13 mm. long; blades
ovate, 10-16 cm. long, 4.5—-8.5 cm. wide, sometimes with a short
obscure lobe on one or both sides near middle, acuminate, at base
cuneate-rounded and decurrent into the petiole, serrulate (teeth
about 40 pairs, depressed, apiculate, o.5 mm. high), papery, above
deep dull green, densely scabrid-hirsutulous (the hairs with lepidote-
tuberculate not glandular bases) and along the veins very densely
sordid-hirsutulous, beneath rather densely subtomentose-pilosulous
with griseous matted hairs (probably finally deciduous) and along
the veins densely sordid-pilosulous, triplinerved above the base;
panicle terminal, ternately divided, pubescent like the stem,
very many-headed, flattish, about 18cm. wide; bracts small;
pedicels 4-10 mm. long, or obsolete; heads narrowly campanulate,
the disk 9-10 mm. high, 4~-5 mm. thick; involucre 2 to 3-seriate,
graduate, 4-5 mm. high, the outermost phyllaries oblong or obovate-
oblong, 2-3 mm. long, 1.2-1.5 mm. wide, with subindurate base and
subequal rounded herbaceous tip, ciliolate, somewhat glandular
and puberulous, the inner similar but oval-oblong, thinner, 2 mm.
wide; rays 2 or 3, pale yellow, fertile, the lamina oval, 6-7 mm.
long, 3.5 mm. wide; disk flowers 8-12, yellow, pilose on tube with
several-celled hairs, 6mm. long; pales minutely apiculate from a
rounded ciliate apex, sparsely pilosulous on back, about 6 mm. long;
achenes (very immature) glabrous; awns subequal, hispidulous
above, about 4.5 mm. long.

Ecuapor.—In shrubbery along roads, Cuenca, September 15, 1920,
E. W. D. and M. M. Holway 994A (type in U.S. National Herbarium no.
1058643).

Allied to V. adenobasis described above, but with different pubescence and
toothing of leaves, larger rays, and much broader phyllaries.

Calea huigrensis, sp. nov.—Shrub 1-3 m. high; stem terete,
densely hispidulous-puberulous and hirsute-pilose with several-
celled spreading hairs, the long ones mostly deciduous or sometimes
entirely wanting; leaves opposite; petioles hispidulous-puberulous
and gland-dotted, corky-thickened at base, 4-7 mm. long; blades

1922] BLAKE—ASTERACEAE 427

ovate, those of the main stem 4-7.5 cm. long, 2—-3.8 cm. wide, acute,
at base rounded or cuneate-rounded, serrulate (teeth small,
4-7 pairs), slightly revolute-margined, papery, harshly tuberculate-
hispidulous above, beneath equally green, densely gland-dotted,
hispidulous along the veins, 3-nerved and prominent-reticulate,
above impressed-veined and rugose; heads in umbelliform clusters
of 5-9 at tips of stem and branchlets, on densely puberulous pedi-
cels 3-12 mm. long, 21-flowered, campanulate, 9-10 mm. high, 4-
6mm. thick; involucre 6-7 mm. high, about 5-seriate, graduate,
the outermost phyllaries ovate, 1.5mm. long, with callous tip,
puberulous and gland-dotted, the middle phyllaries oblong, rounded,
brownish above, subscarious, vittate, sometimes ciliolate, obscurely
puberulous above or glabrous, the inner obovate-oblong or oblong,
rounded, vittate, yellow, scarious, glabrous, all appressed; rays 3,
fertile, golden yellow, erectish, the lamina oblong, 3 mm. long; disk
flowers 18, their corollas golden yellow, glabrous, 6 mm. long (tube
2.2mm., throat cylindric, 3.2 mm., teeth o.6mm.); pales yellow,
scarious, acute, obtuse, or bifid, glabrous, lacerate toward tip,
4.5 mm. long; achenes of ray and disk similar, hispidulous, 2.5 mm.
long; pappus of 20 linear-lanceolate acuminate paleaceous awns
5 mm. long.

Ecuapor.—Banks of old railway grade, Huigra, Province of Chimborazo,
August 7, 1920, E. W. D. and M. M. Holway 856 (type in U.S. National Herba-
rium no. 1058628); same locality, altitude 1525-1675 m., August 21, 1918,
J.N. and G. Rose 22283.

A member of the section EucALEA, related to C. umbellulata Hochr., which
has glabrous achenes and only 6-9 disk flowers. The heads of this species
impart a strong saffron color to the water in which they are boiled.

Gynoxys hypomalaca, sp. nov.—Shrub 3 m. high; stem stout,
subterete, cinerous-tomentulose; young branches angled, densely
cinereous- or ochraceous-tomentose; leaves opposite; petioles
closely ochraceous-tomentose, 1.5-2.7 cm. long; blades ovate or
oblong-ovate, 7-12 cm. long, 2.8-4.5 cm. wide, acuminate, apiculate,
at base broadly rounded, obscurely and remotely serrulate with
inflexed glandular teeth, appearing entire, coriaceous, above deep
green, sparsely pilosulous, quickly glabrate except along the puberu-
lous costa and sometimes the veins, beneath densely and softly

428 BOTANICAL GAZETTE [DECEMBER

griseous- or ochraceous-tomentose with rather loose crisped hairs,
feather-veined, the lateral veins about 10 pairs, plane or impressed
above, prominent beneath, the veinlets finely prominulous-reticulate
above, loosely prominulous-reticulate beneath; panicles terminal,
many-headed, 9-12 cm. wide, ochroleucous-tomentose, the linear-
spatulate or linear tomentose bracts 1 cm. long or less; pedicels
5 mm. long or less; heads 11-14 mm. wide; disk 1 cm. high, 8 mm.
thick; involucre 7 mm. high, bearing at base 3 or 4 linear bractlets
about 4mm. long, the phyllaries 8, densely ochraceous-tomentose
on their exposed surface, oval-oblong, obtuse; rays 7, yellow, the ©
lamina 6mm. long; disk flowers 16-18, their corollas yellow, 7.5
mm. long, glabrous, the teeth papillose at tip; achenes (immature)
glabrous; pappus bristles spinulose throughout, dilated at tip,
6 mm. long. 3

Boxiv1a.—Higher limit of trees, Soraté, April 22, 1920, E. W. D. and M. M.
Holway 567 ndbstey: in U.S. National Herbarium no. 1058605).

ms to be distinct from any of the very numerous species which

have ge described within recent years. Its closest ally is apparently G.
caracensis Muschler, which, according to description, has leaves with appressed
fulvescent-cinereous tomentum beneath, 8-10 ? and 11-14 ¥ flowers, and a
somewhat different involucre. G. hypomalaca comes from the same locality
where MANDON collected so many new species, but of the two new species
properly belonging to the genus, briefly described by ScuHuLtz BIPoNTIUS
from his collections, one, G. mandonii, is of a different group, while the other,
G. asterotricha, agrees in most of the few characters given with G. hypomalaca,
but is said to have cordate leaves.

Mutisia sagittifolia, sp. nov.—Stem slender, supported among
shrubs, essentially terete, obsoletely winged in places, about 2 mm.
thick, at first densely white-arachnoid-tomentose, soon glabrate
and brown; internodes 6-30 mm. long; leaves alternate, terminated
by a simple cirrhus 1-3 cm. long, the blades linear or linear-
lanceolate, 6-8 cm. long, 5-8 mm. wide, usually falcate, acute and
unequal at apex, sessile and sagittate-auriculate at base (the acute
ears 3 mm. long), coriaceous, entire, revolute-margined, 1-nerved,
above quickly glabrous, shining green, impressed-venulose, beneath
densely and persistently white- or cinereous-arachnoid-tomentose ;
peduncles solitary at tips of branches, 2cm. long, apparently
decurved, bearing a single small bract, tomentose like the stem;

1922] BLAKE—ASTERACEAE 429

rays erect, the head 7.5 cm. high, about 5 cm. wide; involucre
strongly graduate, about 7-seriate, 4.8cm. high, funnelform-
campanulate, the three outer series of phyllaries with deltoid or
broadly ovate body and subequal or longer, abrupt, linear or
linear-lanceolate, erect, herbaceous tip (the latter 8-12 mm. long,
1mm. wide), glabrous, the body blackish-green, with thin slightly
wine-colored margins; those of the 4 inner series oval or oblong-
oval, at the broadly rounded apex apiculate and arachnoid-tufted,
otherwise glabrous, the inner thin and wine-colored throughout, the
outer similar to the three outer series in texture and color; pistillate
flowers 13, glabrous, the corollas erect, the tube 2.2 cm. long, the
outer lip elliptic, 4 cm. long, 1 cm. wide, acutely 3-toothed, appar-
ently yellow inside and dark (reddish ?) outside, about 14-nerved,
the inner lip of two narrowly subulate segments 7 mm. long; disk
corollas numerous, apparently yellow tinged with reddish, bilabi-
ate, glabrous, 3.5 cm. long, the throat fenestrate below on both
sides, the lips subequal, about 13 mm. long, one 3-denticulate at
apex, the other 2-parted to base; achenes glabrous, those of the
ray obcompressed, 4mm. long, glabrous, their pappus of easily
deciduous plumose setae 2.5 cm. long; achenes of the disk similar,
the pappus of about 26 plumose setae united at extreme base; ray
flowers with imperfect anthers and glabrous style branches about
0.6 mm. long; auricles of the stamens of the disk 5 mm. long,
acuminate, somewhat denticulate toward apex.

Ecuapor.—On slopes of Mt. Pichincha, August 23, 1920, E. W. D. and
M. M. Holway 941 (type in U.S. National Herbarium no. 1058634).

Allied to M. mathewsii Hook and Arn. in its sagittate-based leaves, but in
that species the leaves are only 1.5 mm. wide, and the involucre only 3-3.5 cm.
long. Only a single plant of the new species was found.

Hieracium pazense, sp. nov.—Perennial, with 2 or more stems,
about 45 cm. high, the root not seen; stems rather stout, branched
from the middle, rather densely hispid-pilose to middle with spread-
ing or reflexed whitish hairs about 4 mm. long, with blackish tuber-
culate bases, above the middle hispid-pilose with wide-spreading
blackish hairs 2-7 mm. long, with subulate bases, the shorter ones
often tipped with blackish glands, and also not densely glandular-
puberulous; stem leaves (below the inflorescence) about 5, the lower

430 BOTANICAL GAZETTE [DECEMBER

obovate, 7.5-13 cm. long (including the 2-3.5 cm. long petiole),
obtuse, apiculate, acuminate into the petiole, sparsely and minutely
glandular-denticulate or subentire, evenly but not densely long-
pilose above (the hairs whitish, with brownish tuberculate bases,
about 4 mm. long), beneath green, similarly pubescent; other stem
leaves oblong-elliptic or oblong-ovate to elliptic, 5-7 cm. long,
1.3-2.2 cm. wide, sessile by a broad base, otherwise similar to the
lower leaves; chief branches of inflorescence about 5, the lowest
subtended by leaves similar to the upper stem leaves, the others
by reduced lanceolate or lance-linear bracts 1-4 cm. long, 1-10 mm.
wide; panicle loose, 20~48-headed, about 12cm. wide; pedicels
pubescent like the upper part of the stem, 7-17 mm. long; involucre
campanulate, 7-8 mm. high in fruit, 2-seriate, equal or subequal,
without evident calyculus, the phyllaries lance-subulate, acuminate,
blackish-green (the inner with thin pale margins), evenly but not
densely pilose with spreading blackish eglandular hairs about 2 mm.
long and especially at base pedicellate-glandular, the hairs blackish
below, yellowish above like the glands; heads about 43-flowered,
the corollas not seen; achenes blackish-brown, 2.2 to 2.5 mm. long,
columnar-ovoid, abruptly contracted downward near base, gradu-
ally narrowed to apex, not at all beaked, about 12-ribbed, minutely
hispidulous especially toward base; pappus brownish-straw-color,
fragile, 5.5 mm. long, equaling the involucre.

Bo.iv1A.—La Paz, March 19, 1920, E. W. D. and M. M. Holway 425 (type
in U.S. National Herbarium no. 1058601).

BurEAv OF PLANT INDUSTRY
WasuincrTon, D.C.

EXPLANATION OF PLATE XIX
Monopholis hexantha Blake.—a, branch, X#; 6, head, X8; c¢, disk
corolla, X8; d,stamens, <8; e, style branches, much enlarged; f, g, two achenes
in lateral and dorsal view, <8.

BOTANICAL GAZETTE, LXXIV PLATE XIX

BLAKE on ASTERACEAE

RECENT STUDIES OF PHAEOPHYCEAE AND THEIR
BEARING ON CLASSIFICATION
Wma. RANDOLPH TAYLOR
Introduction

During the past decade there has been so fundamental an
advance in our knowledge of the reproductive processes and life _
history of the Phaeophyceae, that it seems to exceed in importance
the change in viewpoint regarding any other group of plants during
the same period. The work which must so largely overturn our
ideas has mainly been done by European algologists, and has not
been followed up in this country by any confirmatory studies;
indeed, it seems to be little known. As each succeeding paper, and
several from independent sources have now appeared, confirms the
critical points of the others, it seems desirable at this time to review
the situation and to indicate the necessary changes in the classifica-
tion of the group. To date the only review in English of the studies
in question is a short one by Lewis (11), written at an early stage.
Three have appeared in France, one by CoNsTANTIN (x), and two

by PecHouTrE (16, 17), these latter of special value.

Historical

The pioneer in this field, to whom falls the honor of making the
first clear advance, is SAUVAGEAU. Previous to the appearance of
the standard texts, he, with other workers, had cleared up the
normal life history of Cuileria, showing the relation of Aglaozonia
as the sporophyte stage, and showing the variations in the life his-
tory (parthenogenesis, etc.) which appeared under various conditions
(18, 19, 22, 23, 24). Further, his studies on members of the
Sphacelariaceae and Ectocarpaceae have done much to help in the
understanding of those families (20, 21, 33). Most important in
the present connection, however, are his results from cultures of
Laminariaceae (25-30, 32). In 1910 Drew (2) described the
products of the unilocular sporangia on the surface of the Laminaria

431] [Botanical Gazette, vol. 74

432 BOTANICAL GAZETTE [DECEMBER

frond as functioning as gametes, and as producing a somewhat
filamentous stage from which the mature Laminaria was vege-
tatively developed. A paper by Kix1iAn (5) the following year,
in discussing the development and structure of Laminaria, agreed,
so far as it went, with the statements of Drew. This decidedly
unexpected phenomenon of the sexual fusion of what from their
origin should be zoospores met with considerable doubt, however,
and was attacked by WILLrIAmMs (37), who claimed that it was not
the motile zoospores of Laminaria, but other organisms, which had
been seen to fuse by Drew. The first of SAUVAGEAU’s papers on
the life history of the Laminariaceae appeared as a series on Sacco-
rhiza bulbosa (25, 26, 27). Here he showed that in the case of the
female the germinating zoospores from the unilocular sporangia
produce a one to few-celled filament. The cells of this filament
enlarge and emit a non-motile egg, which seemed to be fertilized in
situ at the aperture, where it developed into a young sporophyte. .
The male plant is more complex, of five or six cells and slightly
branched, with several more or less clustered antheridia. Germina-
tion of the zoospores within the sorus in which they were formed
was seen, and it was found that the sporelings were both male and
female, demonstrating that the sporangia on one plant produced
| both sorts.
_ Following this study appeared one on two species of Laminaria,
L. flexicaulis (L. digitata) and L. saccharina (28, 30). SAUVAGEAU ~
found that in germination the chromatophore of the spore divides
(the zoospore on attaching itself rounds up and forms a firm wall),
and one half passes into the germ tube as it elongates. The nucleus
also divides, and one daughter nucleus with a chromatophore
passes toward the inflated distal end of the tube, where it is cut off
by a transverse wall. The nucleus which remains behind dis-
organizes more or less rapidly, while the cell with the other nucleus
develops the gametophyte. Some of the male filaments are short,
but others are elongate and markedly branched, forming the anthe-
ridia laterally on the branches toward the end. One sperm is
formed in each antheridium, and the sperms are shed before the
female gametophytes in the same culture reach maturity. The
female gametophytes are from one to several cells in extent, all

1922] TAY LOR—PHAEOPHYCEAE 433

cells being able to form eggs. Each cell swells, elongates, and the
egg emerges through a terminal rupture at the end of the pro-
tuberance. The opening of the oogonium forms a sheath around
the base of the egg, which develops into the young sporophyte while
attached to the gametophyte. Actual fusion of the gametes was
not observed.

Promptly following the papers on Laminaria, SAUVAGEAU pub-
lished a similar study of Alaria esculenta, belonging to a differ-
ent section of the same family. The gametophytes differed from
the previous cases in several particulars. The ‘‘embryo spore,”
or zoospore, which has passed into the resting stage, persists and
may give rise to a second filament opposite the first. The game-
tophytes are also larger, and the female has elongate cells, part of
which only seem to produce eggs. The fertile cells form irregular
lobes instead of remaining of the usual simple ovoid form, but only
one egg is extruded from each cell. Sometimes the female thallus
is reduced to a single cell, as is not infrequent in Laminaria, but
is more often of from two to four cells, with the terminal one becom-
ing fertile first, and then occasionally some of the others.

In the same year that the Laminaria and Alaria studies of
SAUVAGEAU were announced (1916), KyYLIN published a paper on
an independent study of the life cycle of Laminaria digitata which
confirmed the statements of SAUVAGEAU in all essential respects (8).
- Kucxuck (7) and Pascuer (15) also later published confirmatory
accounts of studies on Laminaria saccharina, The latter describes
a most interesting departure, where he found that occasionally
cells of the very young sporophyte, or even the undivided egg,
might function as unilocular sporangia producing 2, 4, 8, or 16.
zoospores. Finally, Ikart (4) described the gametophytes of
Laminaria religiosa, which are like the two species already studied
in most points, but at times have the antheridia in rows at the ends
of the branches of the thallus, and shed the sperm by a terminal
pore.

In the year following his papers on Laminaria, SAUVAGEAU
gave an account of the development of Dictyosiphon foeniculaceus,
which demonstrated another unsuspected type of alternation. The
evident plant of Dictyosiphon only produces unilocular sporangia.

434 BOTANICAL GAZETTE [DECEMBER

SAUVAGEAU succeeded in getting good cultures in which the
zoospores germinated quickly to form a branched filamentous thallus
of considerable extent, reaching a millimeter in diameter and forming
hairs. When mature, cylindrical gametangia are formed with
two to twelve loculi. Each cell forms a single gamete. The
septae disappear before dehiscence, and the isogamous gametes
escape by a terminal pore. Conjugation was not observed, but
was undoubtedly present, for a part of the rounded up, quiescent
cells produced from the gametes had two nuclei and two chromato-
phores. Germination soon took place, and produced a short fila-
ment which in a few weeks gave rise to an erect thallus with the
essential structure of Dictyosiphon.

It is a matter of peculiar satisfaction that the work of KLIN (10)
definitely shows Chorda to have the same sort of life history as
Laminaria. The vegetative similarities which this genus shows to
the kelps are not sufficient alone to place it in the same family, but
the demonstration of a precisely similar life cycle removes all
question of the relationship. The gametophytes are considerably
larger than those of Laminaria. Kyttn was able to confirm the
cultural studies by some incomplete cytological details. In the
vegetative cells of the sporophyte tissue there are present forty
chromosomes. Reduction divisions take place in spore formation,
and are followed by two vegetative haploid divisions. Good
fixation was prevented by the paraphyses, and countable meta-
phases were not found, but synapsis, diakinesis, and other condi-
tions typical of the first reduction division were recognized. The
number of chromosomes was about twenty, although it could not
be determined precisely. In addition to the study of, the preceding
species, Kirn has given details of at least part of the life cycle of
several other genera in other families, which will be discussed in
connection with the changes in the classification of those families.

Recently SAuvAGEAU has discovered what he believes to be the
gametophyte of Phyllaria reniformis in the tissues of Lithophyllum
lichenoides (32). Finally, there has appeared a preliminary note
by WILL1ams (38) relating to a detailed study of cultures of Lami-
naria and Chorda, with descriptions of the gametophytes of these
genera essentially as previously outlined. In addition, he men-

1922] TAYLOR—PHAEOPHYCEAE 435

tions having observed the fusion of the gametes and even of the
gamete nuclei of Laminaria, completing the morphological evi-
dence of alternation of generations in that genus.

Classification

It now remains to be seen what effect these recent discoveries
will have on our ideas of the grouping of the genera of the brown
algae. The standard text on the brown algae to date is that of
OLTMANNS (14), published in 1904-1905. The classification used
there differs from that of KJELLMAN of 1891 (6) in several features,
notably in the reinclusion of the Dictyotales in the Phaeophyceae
with the Fucaceae, and in the reduction of several groups of the
Phaeosporeae from the rank of families, including them under the
Ectocarpaceae. The classification accepted by Lorsy (12) is nearly
that of Orrmanns. A recent table by SCHAFFNER (34) disregards
all the more recent discoveries, giving four orders in the Phaeo-
sporeae: Ectocarpales (isogamous), Laminariales (zoospores only),
Cutleriales (anisogamous), and Tilopteridales (oogamous). In the
Cyclosporeae he includes Fucales and Dictyotales. The obvious
fact that only a small proportion of the genera known have been
fully studied, and even that some families are only understood in
the most fragmentary fashion, need not deter us from taking full
advantage of the knowledge which is at hand. It must also be
borne in mind in all cases that parthenogenesis and other kinds of
short cuts in the life cycle may be present, and may be so char-
acteristic of the ordinary propagation of the plant that the funda-
mental type of alternation upon which the classification is based
may be obscured.

The orthodox division into two major groups, Phaeosporales and
Cyclosporales, is still acceptable, provided the former is understood
to include anisogamous as well as isogamous forms, and a wide-
spread morphological alternation. The Cyclosporales include all.
oogamous groups, and may show a reduction from a morphological
to a mere cytological alternation of generations. The first division
of the Class PHAEOPHYCEAE is then the

Order PHAEOSPORALES.—This may be defined as having gametes
isogamous to anisogamous. It includes three suborders, as follows:

436 BOTANICAL GAZETTE [DECEMBER

Suborder EcTOCARPINEAE.—Morphological alternation of similar
generations shown or inferred to be present.

Family 1. Ectocarpaceae.—Reproductive organs formed by
the metamorphosis of all or part of a branch; growth of the free
filaments intercalary. This is the primitive family of the class. In
Ectocarpus the fusion of the elements from the plurilocular sporangia
as gametes has been known since the work of BERTHOLD. Recently
Kyutn (10) has reviewed the work on Ectocarpus, and contributed
a study of two species, E. siliculosus and E. tomentosus. It is to be
considered that the plants with sporangia (unilocular) and those
with gametangia (plurilocular) normally alternate in the life cycle.
Cases of abbreviation of this are well known, and peculiar conditions,
as in E. Padinae Sauv., have been reported (33). The thallus is
always primitively branching-filamentous, and intercalary growth
is typical, but this becomes localized in some species into definite
regions, while the hapteron branches and other attached or endo- ~
phytic parts grow apically. These features are of importance as
indicating the source of similar characters in the following families.

Family 2. Ttlopteridaceae-—Reproductive elements of two
kinds, small motile cells which may function as isogametes, and
larger non-motile cells often with more than one nucleus. These
latter cells are of two kinds according to some accounts, represent-
ing eggs without a membrane and but one nucleus, and mono-
spores with a membrane and usually four nuclei. The oogamous
character of this family has long been tentatively accepted, but
has never been proved absolutely. On the basis of vegetative
characters and an assumed isogamy, this family would stand in
close relationship to the Ectocarpaceae, but if oogamy is actually
present it would need to be placed in the Cyclosporales as a sub-
order Tilopteridineae preceding the Dictyotinieae, differentiated
by the thallus characters and the incomplete division of the spores.
For a discussion of literature see KYLIN (9).

Family 3. Sphacelariaceae.—Reproductive elements formed by
the metamorphosis of all or part of a branch, growth from an apical
cell. The originally monosiphonous filament usually divides up
by internal walls, and may develop a peripheral meristematic zone
producing a very considerable increase in thickness. Special vege-

1922] TAYLOR—PHAEOPHYCEAE 437

tative methods of reproduction are present in most forms. Sav-
VAGEAU (20) reports finding egg and sperm production on one
individual of Halopetris scoparia, but could only find one type of
gametangium in Cladostephus. If this observation is confirmed, it
will either force Halopetris into the Cyclosporales, a removal of the
whole family from its present position, or necessitate a wider inter-
pretation of the Phaeosporales. The family as understood here
includes the Choristocarpaceae of Lemmanaes

Family 4. Asperoc ductive organs formed by
the metamorphosis of, or as an outgrowth from, a superficial cell;
growth intercalary. This family corresponds to the Encoeliaceae,
Striariaceae, and Myriotrichaceae of KyELLMAN, the latter two
representing simpler forms with the same essential construction.
Plants are derived from a simple filament, becoming parenchymat-
ous, either cylindrical or flattened. All stages can be traced.
Gametangia with isogametes and sporangia are present, and con-
siderable portions of the life history are known, especially of Aspero-
coccus and Scytosiphon (10). The statement of YENDo (43) that the
products of the plurilocular sporangia of Phyllitis are not gametes,
but give rise to a microscopic gametophyte, requires confirma-
tion.

Family 5. Chordariaceae——Thallus differentiated into axial
and assimilative filaments, branched, meristem localized; sporangia
5 wepetracd pernliative filaments or modified segments therefrom.

, the final short branches of the axial filaments
turn watwartl and form a close cortex rich in chromatophores.
Since both sporangia and gametangia are known in these genera,
the life history is probably the same as that of Ectocarpus. The
Elachisteaceae of KJELLMAN represent a reduced epiphytic group,
and may best be incincest $ in the causes

Family 6. D R organs formed by the
metamorphosis of, or as an outgrowth from, a fea (or corticating)
branch cell; growth trichothallic. The main axis in these forms is
ramified, and produces short corticating branches, as well as (in
some) delicate free ones. Little is known regarding the develop-
ment of these genera; unilocular sporangia only are present, and
there may be the same life history as in Dictyosiphon.

438 BOTANICAL GAZETTE [DECEMBER

Family 7. Stilophoraceae.—Reproductive organs lateral on
special branched supports, thallus erect on the substratum. As
understood here, this family includes KJELLMAN’s Stilophoraceae,
Spermatochnaceae, and Sporochnaceae. The sporangia are borne
on branched filaments developed from superficial cells of the thallus,
and both sporangia and gametangia are known. Parts of the life
cycle have been traced by KyYLIn (10).

Family 8. Ralfsiaceae.—Reproductive organs at least in part
lateral on special branched supports, thallus incrustating. Here
we may include with the Ralfsiaceae also KJELLMAN’s Lithoderma-
taceae. In both the gametangia are borne laterally on special
branched filaments arising from the surface, but the sporangia are
only so borne in the Ralfsiaceae, in Lithoderma being but modified
surface cells. The life history is unknown from the experimental
viewpoint.

Suborder DicryostpHONINEAE.—Morphological alternation of
dissimilar generations present or inferred, the sporophyte exceeding
the gametophyte in size.

Family Dictyosiphonaceae-—Characters of the suborder. The
forms are branching, have an apical cell, and differentiate axial and
cortical areas. The life history, worked out by SAUVAGEAU (31),
has previously been described. This is a very important group,
as it indicates an intermediate step in the development of a micro-
scopic oogamous thallus, such as is shown in Laminaria.

Suborder CUTLERINEAE.—Morphological alternation of similar
or of dissimilar generations present, gametophyte when different
larger than the sporophyte; growth trichothallic.

Family Cutleriaceae-—Characters of the suborder. The life
history of this group is well known, thanks to the cultural studies
of SAUVAGEAU, CHURCH, and several others, and to the cytological
studies of YAMANOUCHI on Cuilleria (40, 41) and Zanardinia (42).
The alternation shown by the cultural studies has been shown to
be associated with a haploid and diploid nuclear constitution, reduc-
tion taking place in the sporangia. In Zanardinia the two genera-
tions are essentially alike, but in Cwéleria the reduced and flattened
sporophyte was long known as Aglaozonia, and thought to be an
entirely different genus.

1922] TAYLOR—PHAEOPHYCEAE 439

Order CycLosporaLEs.—Plants of this order are strictly
oogamous.

Suborder DicryoTINEAE.—Morphological alternation of similar
generations present.

Family Dictyotaceae—Characters of the suborder. The game-
tangia are aggregated into definite areas or sori, and the asexual
reproduction is by tetrasporangia, motile zoospores being replaced
by four non-motile elements. The life cycle of Dictyota is fully
known. Cultural studies showing the course of the development
have been made by Hovyr (3), and cytological studies by Mottrer
(13) and Wrtu1aMs (35, 36), showing reduction in tetraspore
formation.

Suborder LAMINARINEAE.—Morphological alternation of dis-
similar generations present, gametophyte smaller than the sporo-
phyte.

Family Laminariaceae.—Characters of the suborder. Members
of this family are almost all large plants. Reproduction was
thought to be strictly by zoospores until SauvacEau showed that
the zoospores produced a microscopic gametophyte. The results
of the various studies have previously been described.

Suborder Fuctnear.—Only cytological alternation of genera-
tions present.

Family Fucaceae——Characters of the suborder. This family
forms the spores within pits or conceptacles. Still inclosed, the
spores undergo a few cell divisions, or even only a few nuclear divi-
sions, forming the gametes which are then shed as egg and sperm.
Cytological studies have been made by several workers, including
YAMANOUCHI (39), confirming the morphological and cultural obser-
vations. This is the climax family of the brown algae, and repre-
sents the greatest reduction of the gametophyte possible while
still retaining an alternation.

The writer wishes to express his indebtedness for many helpful
suggestions to Professor I. F. Lewis, of the University of Virginia.
Marine Brotocicat LABORATORY

AND THE
UNIVERSITY OF PENNSYLVANIA

440 BOTANICAL GAZETTE [DECEMBER

LITERATURE CITED

1. CONSTANTIN, J., Travaux recentes sur les Thallophytes. Ann. Sci. Nat.
Bot. X. xxx-xxxvi. 1919.

2. Drew, G. H., The reproduction and early development of Laminaria
erg and L. Seshorian: Ann. Botany 24:178-190. 1910

; , W. D., Alternation of bares a and sexuality in Diciyota dicho-
ro Bor. Gas: 49: 55-57.

4. IkarRI, J., Development oe Lhaleats religiosa Miyake. Bot. Mag.
Tokyo 25:207~-224. 1921

x ee K., Beitrage zur Kanntnis der Laminarien. celta Bot. 3:433-

Igtt

6. ee ee F.R., Phaeophyceae and Dictyotales. In ENGLER und PRANTL,
Die Naturl. Pflanzenfam. 17: 176-297. 1891, 1893.

7. Kucxucx, P., Uber Zwerggenerationen bei Pogotrichum und iiber die
Fortpflanzung von Laminaria. Ber. Deutsch. Bot. Gesells. 35:557-578.
IQI7.

8. Kyzin, H., Uber den Generationswechsel bei Laminaria digitata. Svensk.
Bot. Tidskrift 10:551-561. 1916.

, Uber die Entwicklungsgeschichte und die Systematische Stellung
der Tilopterideen. Ber. Deutsch. Bot. Gesells. 35:298—-310. 1917.

10. , Studien iiber die Entwicklungsgeschichte der Phaeophyceen.
Svensk. Bot. Tidskrift 12:1-64. 1918.

11. Lewis, I. F., Recent work on the life history of the kelps. Plant World
20:190-192. IQI7. °

12. Lotsy, J. P., Vortrige iiber Botanische Stammesgeschichte 12257-3006.

1907.

13- Morrier, D. M., Nuclear and cell division in Dictyota dichotoma. Ann.
Botany 14: riaite. 1900.

. OttmMaNns, F., Morphologie und Biologie der Algen. Jena. 1904-

se PASCHER, A. Uber diploide Zwerggenerationen bei Phaeophyceen Ga
naria sacchurindl, Ber. Deutsch. Bot. Gesells. 36:246-252. 1918.

6. PEcHOUTRE, F., La sexualité héterogamique des Laminaires et la repro-
duction des algues phéosporées. Rev. Gén. Sci. 27:643-653; 688-692.
1916.

17. ———, Revue de Botanique. Rev. Gén. Sci. 30:242-250. 1919.

18. SAUVAGEAU, C., Sur Palternance des generations des Cuéleria. Compt.
Rend. Acad. Sci. 1293555-558. 1899.

19. ————,, Sur une nouvelle complication dans |’alternance des generations
des Cutletiag Compt. Rend. Soc. Biol. 63:139-141. 1907.

, Sur la sexualité de l’Halopteris. Compt. Rend. Soc. Biol. 62: 506-

507. 1907.

, Nouvelles observations sur la germination du Cladostephus verticil-

latus. Compt. Rend. Soc. Biol. 64:695-697. 1908.

20.

21.

1922] TAYLOR—PHAEOPHYCEAE 441

J aAal? Aol mf 7 Ff
5 .

22. SAUVAGEAU, C., Sur la germination
Compt. Rend. Sac: Biol. 64:697-608. 1908.

: la germination parthénogénétique du Cuétleria adspersa.

Compt. Rend. Soc. Biol. 64:699-700. 1908.

24. , Nouvelles observations sur la germination parthénogénétique du
Cuitleria adspersa. Compt. Rend. Soc. Biol. 65:165-167. 1908.

, Sur le développement et Ja biologie d’une Laminaire (Saccorhiza
bulbosa): Compt. Rend. Acad. Sci. 160:445-448. 1915.

26. ———,, Sur les débuts du développement d’une Laminaire (Saccorhiza
bulbosa). Compt. Rend. Acad. Sci. 161:740-742. 1915.

27. , Sur la sexualité hétérogamique d’une Laminaire (Saccorhiza
bulbosa). Compt. Rend. Acad. Sci. 161:796-799. 1915.

28. ————, Sur les gamétophytes de deux Laminaires (L. flexicaulis et L. sac-
charina). Compt. Rend. Acad. Sci. 162:601-604. 1916.

, Sur la sexualité hétérogamique d’une Laminaire (Alaria esculenta).

Compt. Rend. Acad. Sci. 162:840-842. 1916.

, Sur les plantules de quelques Laminaires. Compt. Rend. Acad.
Sci. 163:522-524. 1916.

31. ———,, Sur une noveau type d’alternance des«generations chez les algues
brunes (Dictyosiphon foeniculaceus). Compt. Rend. Acad. Sci. 164:829-
831. 1917.

32. ———, Sur les plantules d’une Laminaire a prothalle parasite (Phyllaria
reniformis Rostof.). Compt. Rend. Acad. Sci. 166:787-789. 1918.

, Nouvelles observations sur l’Ectocarpus Padinae Sauv. Compt.
Rend. Acad: Sci. 171: 1041-1044. 1920.

34. SCHAFFNER, J. H., The plawdiieation of plants. XII. Ohio Jour. Sci.
222129-139. 1922.

35. WiIx11aMs, J. L., Studies in the Dictyotaceae. I. The cytology of the tetra-
sporangium and the germinating tetraspore. Ann. Botany 18:141~-160.
1904. 3

36. ———, Studies in the sen a II. The cytology of the gametophyte
generation. Ann. Botany 18:183-204. 1904.

, The zoospores pe pe Laminariaceae and their germination. Rept.

82d Meet. Brit. Assoc. Adv. Sci. 685-686. 1912

, The gametophytes and fertilization is Laminaria and Chorda,

Ann. Botany 35:603-607. 1921.

39. YAMANOUCHI, S., Mitosis in Fucus. Bot. GAz. 47:173-196. 1909.

40. , Cytology of Cutleria and Aglaozonia; a preliminary paper. Bor.
GAZ. 48: 380-386. 1909.

, The life history of Cuéleria. Bor. GAz. 54:441-502. 1912.

. , The life history of Zanardinia. Bor. Gaz. 56:1-35. 1913.

43- YENDO, K., The germination and development of some marine algae. II.
Bot. Mag. Tokyo 33:171-184. 1919.

38.

41.

A METHOD FOR ESTIMATING HYDROPHILIC COLLOID
CONTENT OF EXPRESSED PLANT
TISSUE FLUIDS!

ROBERT NEWTON AND ROSS AIKEN GORTNER

(WITH ONE FIGURE)

In the preceding paper by GoRTNER and HorrMAn? it was
pointed out that studies of the physico-chemical properties of plant
saps which include only measurements of the osmotic pressure,
electrical conductivity, and H-ion concentration, leave out of
account the very important influence on physical properties exerted
by sap colloids. By the introduction of the refractometer as a
part of the field laboratory equipment, these workers have shown
it possible to make rapid and accurate determinations of the
moisture content of the plant saps. Utilizing the additional data
thus made available, a simple method has been devised which
appears to give a relative measure of the content of hydrophilic
colloids.

The freezing point depression of the freshly expressed plant
juice is first obtained. Then, having determined the total solids
by the refractometric method, a quantity of sucrose just sufficient
to make a molar solution in the total water present is added. The
freezing point depression is again determined, and is usually found
to have increased more than the theoretical amount.

The values for the excess depression recorded in this paper have
been based on the assumption that sucrose forms the hexahydrate
in solution. The evidence for this has recently been discussed by
SCATCHARD,’ who also contributed additional data. In prelimi-
nary experiments with pure sucrose dissolved in distilled water,
freezing point depressions were obtained slightly in excess of those

* Published with the approval of the Director, as Paper no. 323, Journal Series,
Minnesota Agricultural Experiment Station

? GorTNER, R. A., and Horrman, W. F., Determination of moisture content of
expressed plant tissue fluids. Bor. Gaz. 74:308-313. 1922.

3 ScaTcHARD, G., The hydration of sucrose in water solution as calculated from
vapor-pressure measurements. Jour. Amer. Chem. Soc. 43:2406-2418. 1921

Botanical Gazette, vol. 74} [442

1922] NEWTON & GORTNER—TISSUE FLUIDS 443

expected under this assumption, but it is preferred to use the
theoretical value until further data on this point are available.

It is assumed that the magnitude of the excess depression is a
measure of the quantity of water held in such a way as to be unavail-
able for the solution of the sugar. The values obtained may be
calculated to percentage “bound” water. This represents the
total water of hydration of all the substances in the sap, but has
been found to correspond so regularly with the content of hydro-
philic colloid as to indicate a close relationship. It seems probable
that in most cases the water bound by substances other than colloids
is of minor importance.

In table I are reported the data for a number of the samples of
expressed juice included in table I of the preceding paper, and in
addition for a series of gum acacia sols prepared by weighing out
the necessary quantities of highly purified gum acacia and distilled
water. The percentage of total solids, as read directly by the
refractometer, is given in column 2. The values for viscosity,
recorded in column 3, were determined by a viscosimeter of the
Ostwald type, in a constant temperature bath at 25° C.; the figures
are the number of seconds required for 3 cc. to flow through a
capillary tube, through which the same quantity of distilled water
flowed in 204 seconds. In column 4 is given A, the freezing point
depression of the freshly expressed juice; in column 5 A,, the
freezing point depression after the addition of the sugar; in column
6 A.—A, the actual additional depression due to the added sugar;
in column 7 A,—(A+K,,), the amount by which the depression
found on addition of the sugar is in excess of that expected on
theoretical grounds. As previously noted, it has been assumed that
sucrose forms sucrose hexahydrate in solution, and therefore Kp,
the molecular constant for the depression of the freezing point, has
been taken as 2.085° C. instead of the usual 1.86° C. The percent-
age ‘“‘bound” water, given in the last column of the table, is con-
veniently calculated from the value for actual additional depression
due to the added sugar (A.—A). The calculations involved will be
made clear in the following example, using the first item in the table.

1.86°=A due to 1 mole dissolved in 1000 gm. water, but 1 mole
sucrose combines with 6 moles water. Thus 1 mole sucrose dis-

444 BOTANICAL GAZETTE [DECEMBER

solved in tooo gm. water=1 mole sucrose hexahydrate dissolved
in 1000—(18X6), or 892 gm. water, and 2.085° (K,»,)=A due to
1 mole dissolved in 892 gm. water.

But in sample 13 the increase in A on addition of 1 mole sucrose
(A.—A) was 2.339°, and 2.339°=A due to 1 mole dissolved in
1.86X 1000

2.339
892—795 =97 gm.,=9.7 per cent.

In laboratory practice it is most convenient to weigh out a fresh
portion of the sap containing 10.0 gm. of water, add 3.422 gm. of
sucrose, and redetermine the freezing point. The percentage of

Excess A > 892
observed A—sap A

=795 gm. water; therefore the water bound per liter =

bound water is then given by the formula:

A,— (A+ K,,)
water=
or bound water RoR

X 892.

Comparing sample 13 with sample 16, it will be seen that whereas
the percentages of total solids vary widely, the percentages of bound
water are not greatly different. A reference to the values for
viscosity and A will indicate at once the marked difference in the
physical properties of these two saps, due to the large content of
colloidal material in sample 16, a fact which is strikingly reflected
in the percentage of bound water. Again, dialysis showed that
material similar to sample 17 contained approximately twice the
quantity of colloids as was contained in material similar to sample
20, and these two samples differ widely in percentage bound water.
These examples are cited to illustrate the application of the method.
Discussion of the significance of the variations observed in the wheat
varieties is reserved for a later paper on another subject.

The percentages of bound water obtained with gum acacia sols,
as shown in the table, increase regularly with concentration. In
fig. 1 the percentage concentration has been plotted against the
percentage bound water. The logarithms of these values have
also been plotted in the same figure. It will be seen that both of
these graphs suggest an adsorption curve.

The advantages of sucrose as the solute in this method are as
follows: (x) it is easily obtained in a high degree of purity; (2) the
large molecular weight reduces errors in weighing; (3) its behavior

NEWTON & GORTNER—TISSUE FLUIDS 445

1922]

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I ATAVL

446 . BOTANICAL GAZETTE [DECEMBER

PERCENTAGE BOUND WATER .
ss ‘

NOILVYLNIINOD JDVINIINAd

. op ° 9
LOG |BOUND WATER

NOILVULNIINOD DOT

oe 1.—Relation between concentration
gum acacia sols and water bound by the ie.

Division oF AGRICULTURAL mbes our
UnNIvErsiry oF MINNESOT.

in solution is fairly well
known; (4) its effect on the
swelling of colloids is prob-
ably negligible. In objection
it may be stated that plant

been followed of grinding
the sucrose to a fine powder
which dissolves rapidly with
shaking, and the sap has been
maintained continuously at
low temperature. Under
these conditions no increased
depression of the freezing
point which could be attri-
buted to invertase action has
been observed in a somewhat
extended series of determi-
nations on the same sample.

Conditions of equilibrium,

-and possible errors due to

adsorption of the sugar by
colloids, have not yet been
investigated. The data
already secured, however, ap-
pear to justify the proposal
of the method for the esti- .
mation of the relative (not
absolute) content of hydro-
philic colloids in expressed
plant tissue fluids. Itseems
probable that the method
may be applied also to other
biological fluids.

GROWTH OF PLANTS IN ARTIFICIAL LIGHT
R. B. HARVEY
(WITH TWO FIGURES)

The growth of plants in artificial light has been of interest in
plant physiology because it offers the possibility of controlling the
quality and intensity of the light, and the duration of the exposure.
No reliance can be placed upon sunlight, and its quality and
intensity vary greatly. The writer attacked the problem of growing
plants in artificial light to gain some idea of the relation of light
intensity to the formation and equilibrium concentrations of the
carbohydrates formed in leaves, and to the translocation of these
substances in light and darkness.

The problem of producing plants in artificial light is of some eco-
nomic interest in Minnesota and other such localities, where the
sunlight is of short duration and low intensity in winter. It is
difficult to raise plants in the greenhouse in winter in this latitude
when the sun is at a low angle. Some analyses made on cabbage
leaves grown in a greenhouse at the University of Minnesota in the
winter of 1920 show a practical absence of sugars from the leaves.
Very little growth is produced under such conditions; the plants
are weak and easily attacked by fungi.

The ability to grow plants in this climate by substituting
artificial light for sunlight, or by using artificial light to supplement
sunlight on dark days, will be of considerable value for plant
breeders. The progeny of valuable crosses can be carried through
one or more generations during the winter, and thereby decrease
the time required to produce a new strain. In breeding for rust
resistance at Minnesota it has been found difficult to carry biological
forms of black stem rust of wheat in culture during winter, owing
to the weakness of the host plants.

The writer has succeeded in raising a great variety of plants
from seed to maturity, using artificial illumination entirely. Light
was obtained from nitrogen-filled tungsten filament (Mazda)
lamps. The lamps were mounted on the ceiling of basement rooms
447] [Botanical Gazette, vol. 74

448 BOTANICAL GAZETTE [DECEMBER

about five feet from the plants. Ordinary enamelled reflectors of
the deep bowl type were used to throw the light downward. The
lamps used were of the 200 watt and 1000 watt sizes; the latter is
considerably more economical in operation than the smaller size.
These lamps are rated to burn rooo hours, but average about
3000 hours. They were burned twenty-four hours per day, so that
one set of lamps was sufficient for four months or more. Breakage
of the lamps occurred the most frequently when the current was
turned off and the filaments allowed to cool. The continuous
burning seemed to greatly increase the life of the lamps.

Plants grew well, set good seed or produced tubers in the
continuous illumination. It seems unnecessary to have a period
of darkness to allow translocation of the assimilate from the leaves.
Several intensities of light were used and the plants grew in each.
The lowest intensities of about 25 foot candles in dark corners
produced much better growth than was obtained in the greenhouse
during the winter. Analyses of the carbohydrate and protein
contents of the plants are being made.

In one room 8X11 feet a great variety of cereals was grown,
including twenty varieties of wheat, fifteen varieties of oats, eighteen
varieties of barley, eight varieties of rye, six varieties of flax, several
hybrids of wheat and of oats, and a few other test plants. The room
was lighted by lamps with a total capacity of 3200 watts and
distributed uniformly: The lamps required about 0.6 watt to
4 7 X3200

produce one spherical candle. Then = 67,021 lumens

total flux. On account of the light absorption and inefficiency of
the reflectors, only about 60 per cent of this light reaches the ground,
so that there are 40,212 lumens spread over the area 8X11 feet,
giving an intensity of about 457 lumens per square foot. In this
light winter rye headed at about 24 inches; Kota wheat at 28
inches; Bluestem wheat at 23 inches; Aurora oats at 17 inches;
Manchuria barley at 17 inches. These plants were grown in 5-inch
pots. Usually six or eight kernels were all that set in a head of
wheat, but these were plump and full of starch. The temperature
was maintained automatically at about 14°C. by cooling with
outside air. It was unnecessary to use any heat in this room
other than that produced by the lights. The light is doubly

1922] HARVEY—ARTIFICIAL LIGHT 449

efficient, for all that is not used by the plants goes to heat. Since
sunlight is not required, the rooms can be insulated much better
against heat loss than a greenhouse.

In a room 6X11 feet, lighted by 10-200 watt lamps, several
vegetables were grown. The temperature was about 25°-30° C., not
well controlled. The light intensity was about 380 lumens per
square foot. Potatoes and tomatoes grew well, but were somewhat
taller than normal. Early Ohio potatoes bloomed when the vines

Fic. 1.—Cabbage, lettuce, potato, tomato, beans, peas, and a number of other
plants growing in continuous artificial light; room 6X8 feet, lighted with lamps of
2600 watts capacity.
were 44 inches long. Boston marrow squash bloomed at 42 inches,
but did not set fruit. Alaska peas bloomed at 18 inches and set
good seed. Solanum niger set abundant fruit, beginning at 6
inches, and continued fruiting up to 28 inches. Cabbage started
heads at about 18 inches and showed some effects of etiolation.
Buckwheat set normal seed at 20 inches.

In another room 6 x8 feet, lighted by lamps with a total capacity
of 2600 watts, the plants appeared much more normal than in the
room just mentioned (fig. 1). The light intensity here was about
680 lumens per square foot and the temperature 25°-30°C. Cabbage

450 BOTANICAL GAZETTE [DECEMBER

headed at 12 inches; lettuce set abundant seed when 36 inches high.
Black wax beans set pods at 35 inches; potatoes (Early Ohio)

Fic. 2.—Rotating tables operated by electric phonograph motor to equalize
light and temperature.

1922] HARVEY—ARTIFICIAL LIGHT 451

bloomed at 48 inches, and set tubers weighing as high as 180 gm.
each. White sweet clover set some seed when 4o inches high.
A number of weeds were allowed to grow, and they all set abundant
seed. Boltonia asteroides bloomed when 54 inches high; Cheno-
podium ambrosioides set seeds profusely at 35 inches; Silene latifolia
bloomed at 16 inches but did not set seed; Stellaria media bloomed
and set seed at 16 inches; foxtail grass (Alopecurus) set abundant
seed at normal height.

Under the todo watt lamp shown in fig. 2 the light intensity
was about 4188 lumens per square foot. Plants under this light
were very stocky, and showed effects of too much heat. The leaves
of cabbage were very turgid and stiff. The plants were rotated to
equalize light and temperature, and to decrease the heating effect
of the light on surfaces directly exposed.

All of the plants in these rooms except cabbage bloomed, and
many produced good seed, although the illumination was continuous.
It seems then that the period of illumination is not the factor which
determines whether a plant will bloom or not. The results obtained
by GARNER and ALLARD‘ may have been produced by a modification
of the conditions of nutrition of their plants by variation in the
length of the day. It is possible to obtain seed from a great variety
of plants as here shown, although the illumination is continuous,
and the intensity is approximately the same for’all plants in one
room.

Summary

A great variety of plants, including wheat, oats, barley, rye,
flax, buckwheat, white sweet clover, peas, beans, lettuce, and a
number of common weeds were grown from seed to maturity in
continuous artificial light, and all set good seed. Potatoes, toma-
toes, red clover, alsike clover, squash, and Silene bloomed, but did
not set seed. Potatoes produced tubers of good size. All of the
plants tested did not require a certain period of illumination to
cause them to bloom. It is possible to produce seed from plants
in winter independent of sunlight, and at no very great expense.

UNIVERSITY FARM

St. Paut, Minn.

* GARNER, W. W., and Atrarp, H. A., Jour. Agric. Res. 18:553-606. 1920.

CURRENT LITERATURE

MINOR NOTICES

North American slime moulds.—A new and revised edition of MACBRIDE’S'
North American slime moulds has just been published. As the subtitle states,
it is “‘a descriptive list of all species of Myxomycetes hitherto reported from
the continent of North America, with notes on some extra-limital species.”
- The original edition was reviewed in this journal.2 The necessity for a second
edition has given the author the opportunity not only to correct certain errata,
but chiefly to incorporate new information developed by the investigation of
the last twenty years. The book is primarily for American students, and is
certainly an adequate presentation of this interesting group, serving the same
purpose in this country that Lister’s Mycetozoa does in England.—J. M. C.

Some elementary texts.—An interesting textbook for Indian high schools
has been prepared by KENovER. It is interesting both in presentation and
material, and adapted to high school students of India. Of course it is neces-
sarily brief, but it develops an interesting approach to the plant kingdom. It
is based upon the conviction that the best way to know plants is to grow
them, and therefore emphasis is placed upon the school garden as the important
laboratory for beginners. The plants selected as illustrations are in general
those of general occurrence in India. This little book will interest teachers of
botany in other countries.

A similar text for English schools has been prepared by WoopHEAD.*
This is an abbreviation and simplification of the author’ s The study of plants.
It also emphasizes the study of living material, experimental work, and out-

Both are doubtless adaptations to the status of high school education in the
two countries.—J. M. C.

*Macsriwe, T. H., The North American slime moulds. 8vo. pp. xvii+299.
pls. 23. New York: The Macmillan Company. 1922.
2 Bot, GAz. 29:74. 1900.

3 Kenoyer, L. A., Plant studies for ne aie schools. pp. 160. figs. 67. The
Christian Literature Sockéty, Al ba

4 WoopHEaD, T. W., Junior ane pp. 210. figs. rgo. Oxford: Clarendon
Press. 1922.

452

GENERAL INDEX

Classified entries will be found under Contributors and Reviewers. New names
and names of new genera, species, and varieties are printed in bold-face type, syno-
nyms in italic.

Chauveaud, G., “La anager des
A
plantes vasculaires”
Se, glandulosa 414; hyper- | or sariendah of vegetable cell 222
chlora Chionoloma 224
rican Sa 158 Coffman, F. A. 197 eee
pollination in 197 tent, met g
Alternaria from C ape 320 { “sei si mutation 340
t-plant: tro} Compton, R. H., work of 224
Aquatic plants, biology of 221 Conard, 5
rber, ae 80; “Water plants” 221; | Conifers, mycorhiza o
ork of 3 Contributors: Arber, Agnes 80; Atwood,
Arber, E. - x, work of 229 W. M. 233; Bailey, I. W. 369; Benson,
Aschersonia Margaret 121; Berry, E. W. 320;
Aancunpeetne £1 - Blake, S. F. 414; Brown, J. G. 228;
Asteraceae, South caaias 414 Chamberlain, C. J. 222; Coffman, F. A.
Atwood, W. M. 2 197; Conard, H. S. 335; Coulter, J. M.

120, 223, 224, 231, 232) 330» 342) 3435
B 344, 452; Coulter. .M. C. 226; Davison,
Bailey, I. W F. R. 104; Dui ee 264 Dupler,
341, 342; Fink, B. 115; Fuller, G. D.
118, 119, 120, 341, 342, 344; Gericke,

EEE
aE
Q

rium
ella 224 . ‘.
Benson, Margaret 121 zs ee eg Sones ee 3 a
Berry, E. W. 329; work of 232 308 fobet F E. 333 Hyde B.C
Biochemistry of plant diseases 104 186: Johnston E.S 31 4 urica, H
Blake, S. F. 414; work of 225 oe ha OW 114. 337) 339
Blakeslee, A. F., f 226 Milb BG. <a: Newton, &
Breazeale, J. F., w I 442; ‘ se "230, 231, 232:
Bridges, C. B., work of 227, 340 Poole, R. F. 210; Ramse B.. 3255

riggs, L. J., work of : Robbins, 5 Rudolfs, W. 215;
me ee ae eee ee

- W.95 : “
Brown, J. G. 228 F. W. 174; Taylor, W. R.. 4333 Thone,
Brown, W., work of 228 F. 345; Walton, G. P. 158; Water-
man, W. G. 1; Willaman, J. J. 10
ty Wylie, R. B. 221

Calamites 229 Corn, root tips of 59
Calea hades eels 426 Coulter, yy M. 120, 223, 224, 231, 232,
California, Alternaria from 320 339) 342) 343) 344, 452
Caprifoliaceae, of Korea 225 Coulter, M. C. 226
— ier, A., work of 230 pees as w species of 2

ecropia angulata 378 cgus, Hew &
Chamaebryum 224 ~ Cucur' bita, inhe — of fruit shape 95
Chamberlain, C. 7 222 Cycadofilicales

453

454

D
Dastur, R. H., bia of 231
Davison, F.
ecazyx 225
De La Vaulx, R., work of 229
Diels, L., work of 2 225
Dim hi

work of 224, pose po 344

264
Sones A. W. 143, 331
Dutch New Guiana, mosses of 224

E
Eaton, S. V. 32, 231, 341, 342
Ecological factors of Starved Boke 345
Electrons in photosynthesis 336
Eme ., work of 22
n, J., work of 337, 339

Eupatorieae 22 22
Evans, W. as: ak of 225

Farinosae, leaves of 80
Fink, B. 115
Flax rettin, g, microbiology of
gi plants, phot aya ccontvel of

pea ERE e, st hos wheat 233

Fruit rot of toma

uller, G. D. rx “ Me aie 341, 342, 344
Fungi, morphology and cytology of 114

Gall, o: pte opioe tri gi as 186
Fan ioeee 1a . M., work of 225
Geoglossaceae , development of 264
Gericke, W. F.1 >

08, ‘ae
Be “6 Chemie der Pflanzenzelle”’
tt and Honduras, new species
Guilliermond, A. T., Biboe sase 335
Guyer, M. F., work of 2
Gwymne-Veughan, Dain Helen, “Fungi”
Guns hypomalaca 427

H
Harvey, R. B. 447

12
Heterotheca Grievii 121

INDEX TO VOLUME LXXIV

[DECEMBER

Hieracium pazense 429
Hitchcock, A. S., work of 118, 224
H W. F, hs

offman,
Hooker, H. D., work of 342
Host, influence és ade 228
Hubert, E. E. 333
Hyde,

K. C. 186
Hydrogen-ion Aecgisur eso effect of
seeds upon

: Hiydropteracee, mesozoic representative

pe itd 226

I
Illinois, vegetation of 342
Indian Gondwana plants 331

gare wee oe cambium in monocoty-

ledon:
naan Tei of 344
soetes 339

J
Jennings, H. S., work of 226
Jennings, O. E., re rk of 230
sepa on, E. S.3
mes, F’. asia ne a 341

Suis
K
pect ay a 22
ss ‘Plan studies for Indian
ert kere
L

Lawfield, F. W., work of 229
, work of 120
areal

Leaves of

Le sere perce of 226

Tite

Light, ore of S pepeps in artificial 447

Lindau, G., work

Lundegar ardh, H., oe ay a

Lye isporangiate sporophyil of
mat: peothidiie of 392

Macbride, T. Pi “North American slime
moulds” 4

McDougall, WY. — Bae ge of 344

Mag 1esia injury 1

Martin, G. W., ey 337 339

Marty, 'P. , work of 229

Mesozoic flora 232

Michigan, sand ridge region 1

4 ind

1922]

Milbraith, D. G. 3

Missoula region, fos plants from 230
Moisture content, of expressed plant

_tis sue ‘fluids st of peach buds 314

lsat ciate 416; hexantha 418; hol-
peo 419; jelskii 420; pallatangensis

io disease of tobacco 342
Muller, H. J., work of 227
: : fs) . 428
ycorhiza of conifers 344

N
Nasskeniin Ts ae of 224, 225

ang Caletonie and the Isle of Pines, -

plants of “ee

Newton, R

Nilsson-Ehie, t HL, work of 3

aptncig hepa TS, featieath of apple
trees to 342

; — deoslondes and temperature

Noe gs C. 229, 230, ates 232
North American flora

Octomyrtus 225

Oedipodiella 224

Osborn, T. G. B., work of 3390
ophytes over rinestone 120
Ozark forests 341

Palm, B. T., work of 342
Palmer, E. re work of 341
Sai Myrtaceae of 22

Pea ch buds, moisture content of 314

Pellia, fungus sin 3

Perymenium ecuadoricum 423

Petch, T. Se tae of 2

Phaeophycea 431

Phot resco sae pen in forest plants
ectrons in

yscomi ag
ep pry ss ——

Polymnia eurylepis 415

INDEX TO VOLUME LXXIV

455

Polypodium, prothallia from sex organs
of 120

Poole, H. H., work of 336

Poole, R. F. 210

ne oe trichocarpa, anatomy of gall on

Potaseiog, germ id of 231

Prosanerpis
Prothallia trot sex organs of Polypodium
120

Queensland, fossil woods of 232

Ramsey, G. B. 3
oe eeclariaeacee embryogeny of

Ieee of apple trees to nitrogen

fertilizers 342

Reviews: Arber’s “Water plants” 221;
Chauveaud’s a nstitution des
plantes vasculaires” 223; raf
‘Chemie der Pflanzenzelle” 222; Guil-
liermond’s ‘‘ Yeasts” 335; e-
Vaughan’s “Fungi” 114; Kenoyer’s
oi Plant studies * Indian high schools”
452; acbri orth American
slime moulds” 4 pit — “Guide to
poison plants” 222; ’s
“‘Lichens” 115; Thomson’s “Guide
to poisonous plants” 222; W.
“Junior botany” 452

Ridler, W. F. F., work of 344

Robbins, W. J. 5

Robinson, B. L., work of 225

Rocky Mountain fi

Root tips of corn 59

Rudolfs, W. 215

Rumex a icus, specific acidity of
water a and oxalate content of
foliage 1

Rydberg, P DA, work of 344

5
Sagenopteris 3
Sahni

, ae wok fa 231, 232
. J., work of 120

prone J. H., work of 232

Sclero inerea, plums rotted hd 104

Seeds, “elect of upon hydrogen
centration 215

Seward, A. C., work of 231

456

See o fruit in Cuciirbiga
hull, C. A. r19, 222, 736, 344
Sifton, H. B., “Guide to poisonous
_plants” 222 :
innott, E. W, 95

Slime moulds, No can 452
mith,,Annie DA TES wins!
Smi ;

aW:,

Soil, "moisture 118 8; Pir icocse mical

problems of 119; — content of 32
Spaulding, P. geen
Spessard, E. A.
Starved Rock, Sige factors of 345
Steil, W. N., work of
Steiractinia rosei vo

Stock-p

Structure, ¢ effect ‘of abe - 343
Sulphur content of soils 3
Syringidium 224

fi
Lage N., work of

efsen, hMaxjore A., work of 343
d nodule development
aat; — for controlling 333
Thomson, R. B , “Guide to poisonous
plants” 222
Thone, F. 34
Tisdale, W. Bot Mowe of 341
Roaech. a of 342
Tomato, new > ienit rot of 210; parasite

INDEX TO VOLUME LXXIV

[DECEMBER 1922

Umbe liferae, ai ee ai study of 292
Uredinales
Eiainalie sis

Variations, origin of 226
Vascular plants, constitution of 223
a ogy multiplication, new method

Vachouka, adenobasis 425; latisquama

Viola, new species of 224 |

W
sda oes G. P. 158
rman, W. G. 1
Weddin holwayi 4203 Seaton 421
eat, effec dehyde 233;
ioe. Powe Briers salt injury of

White cine blister oo 339
Willaman, J. J. to.
Woodhead, ae Ws i viaded botany? 452
Wylie, R. B. 221
xX

Xanthonmyrtus 225

Y
Yeasts 335

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