ie 12. X3I10.
Fic. 14.—Body cell nucleus of fig. 13. 1240.
1G. 15.—Upper half of median longitudinal section of nucellus, 1”, and
prothallus, p, showing position of pollen tube and of archegonia; drawn from sev-
eral . t, pollen tube; January 7, 1909. X28.
Fic. 16.—The lowest group of archegonia of jig. 15, two containing pro
sunbigee Xt
G. 17.—Suspensor bearing a single embryo cell at its apex; note multi-
nucleate prothallus cells in this and previous figure; s, suspensor; ¢, embryo cell;
January 7, 1909. X310.
1G, 18.—Very young embryo in median longitudinal section; March 8, 1968
Fic. 19.—Older embryo, showing dermatogen differentiated and embryonal
tubes; January 7, 1
Fic. 20.—Outline sketch of median longitudinal section of nearly mature
embryo; March 8, 1908. Xg.
Fic. 21.—Two multinucleate cells from an old prothallus; March 8, 1908:
X54.
Fic, 22.—Dividing nucleus from an embryo between the ages of those shown
in figs. 17 and 18 respectively. X 1500.
BOTANICAL GAZETTE, XLVIII
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PLATE XI
THE BEHAVIOR OF THE CHROMOSOMES IN
OENOTHERA LATAXO. GIGAS
OCNTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 128
REGINALD RUGGLES GATES_
(WITH PLATES XII—XIV)
The hybrid which forms the subject of this paper is of peculiar
interest because one of its parents has double the number of chromo-
somes possessed by the other, O. Jata having usually 14 chromosomes
and O. gigas 28. Very few cases of this sort are known, either in
plants or animals. But a further complication arises in the fact
that O. gigas is known to have originated from O. Lamarckiana,
which also has 14 chromosomes, and O. gigas has in all probability
attained the tetraploid number by a duplication of the chromosome
set present in O. Lamarckiana.:_ Then if fertilization took place in
the ordinary manner, the hybrid O. lataX O. gigas would be expected
to have 21 chromosomes, 7 derived from the lata egg and 14 (which
is probably a double set of Lamarckiana chromosomes) derived from
the male cell of gigas. Under these circumstances, the behavior of
the chromosomes in the hybrid, especially during the period of reduc-
tion and germ-cell formation, is a matter of especial interest.
The general results regarding chromosome numbers and distri-
bution were obtained some time ago, and a brief statement was pub-
lished (10), but the cytological evidence is here presented for the
larger ones, there has been a transverse split of the D. rotundifolia ch
179] [Botanical
180 BOTANICAL GAZETTE [SEPTEMBER
first time. Many of the drawings for these figures were completed
about two years ago, but my interest in other phases of this work has
postponed their publication until now. The earlier stages of reduc-
tion in Oenothera, up to the end of the heterotypic mitosis, have
already been described in detail (11), so that this paper will deal
chiefly with the later stages, beginning with the metaphase of the
heterotypic mitosis.
The plants from which these studies were made were grown at
Wood’s Hole, Mass., in 1g05 and 1906, from seeds of DEVRIES.
The results show that in some cases the number of chromosomes is.
undoubtedly 21, while in one individual it was 20.2. The number is
undoubtedly constant in an individual, however, as shown by @ —
large number of counts, which demonstrated constantly 20 in one
case and 21 in the other. q
The external characters were not studied with sufficient care at
that time to describe them accurately, but from my notes they appeal
to have been intermediate between O. lata and O. gigas. DEVRIES
has described in a recent paper (5) the hybrids of O. gigas with other
forms. I have called attention elsewhere to the fact that the behavior
of O. gigas in hybridization, as well as its number of chromosomes,
places it in a different category from the other mutants of O. Lamarcki-
ana. DeVries finds that O. gigasxO. Lamarckiana forms a Com
Stant race intermediate between the parents, at least to the second
hybrid generation. O. gigasxO. Lamarckiana, O. Lamarckiana
XO. gigas, O. gigasXO. brevistylis, O. gigasxO. rubrinervis, and
O. rubrinervisXO. gigas, all give constant hybrid races which at
externally alike in all these crosses. O. lataXO. gigas; howevel
gives in the F, two types, about 50 per cent. of each; type I inter
mediate between O. lata and O. gigas, type II intermediate between
- Lamarckiana and O. gigas. These presumably would all ae
about 21 chromosomes. There were 13 3 plants in the culture :
this hybrid in 1907 and a smaller number in 1908. :
Miss Lutz (24) from a study of 4o individuals of O. lata XO. 88°
finds more complex conditions in this cross, though apparently *
* In my first paper (8) this individual was thought to be O. lata XO. Lamarcke*
soa shed mks rd —— to be derived from fertilization by foreign signs lene
particular seed pac not having bee when
were plarited. Be ng been guarded as was supposed
Pe Pat eT eee
wet ee rane
wart ts aed ee
1909] GATES—CHROMOSOMES IN OENOTHERA 181
_has failed clearly to recognize the types included in her class II.
_ She divides the offspring into three classes. Class I has the characters
of pure O. lata, and the two individuals which appeared are each
_ Said to have 15 chromosomes. Class IT consists of O. gigas plants
_ having about 30 chromosomes. There were six of these plants, and
their presence cannot be accounted for by the ordinary methods of
fertilization. If the O. gigas male cell united with two O. /ata nuclei
in the embryo sac, this would account for the origin of the O. gigas
number of chromosomes. But GEERTS (12, 13) finds that the
embryo sac of Oenothera contains only four nuclei, the egg, two
_synergids, and one polar nucleus, so that the possibilities here are
_ more limited than in an 8-nucleate sac.* The class III of Miss Lutz
apparently includes both the types of DEVRrEs’s cross, but they are
- hot characterized so that a comparison can be made.
These interesting facts all show that there is still much to be
_ explained regarding O. gigas and its hybrids. In the paper already
_ referred to, I have shown that, in all the tissues examined, the cells
_ are larger in O. gigas than in O. Lamarckiana, though the percentage
_ of increase varies in different tissues. The production of the tetra-
ploid number of chromosomes results in larger nuclei and larger cells,
and this in turn in many cases produces larger organs. Certain
changes which are found in the relative dimensions of the cells will
a account for the altered shape of certain organs. Thus the differences
3 between O. Lamarckiana and O. gigas can probably be analyzed
__ into two factors, (r) increased size of the cells, and (2) altered relative
a dimensions of the cells in certain cases. The former undoubtedly
2 ‘embryo sacs are produced without reduction (a ously or aposporously), in
= which case the egg develops without fertilization. I hope to test this hypothesis
_ ©xperimentally this summer
a 4 Whether an individual with the tetraploid number of chromosomes would have
a the O. gigas characters, owing to its number of chromosomes rather than their 2g
4 18 a question I have considered in a forthcoming paper (footnote 1). bet inietsare
182 BOTANICAL GAZETTE {SEPTEMBER
results directly from the doubling of the chromosome number; at
least the double number of chromosomes and the larger size of cells
occur simultaneously. Whether the latter isa necessary consequence
upon the increase in cell size and a resulting change in cell relations,
or is due to an independent factor, is uncertain. It should be said
that characters, such as leaf shape, which might be accounted for
by a change in the relative dimensions of the cells (though I have not
as yet made measurements of the leaf cells to determine this), are
extremely variable, and it seems not unlikely that this extreme varia-
bility may result from variation in cell dimensions consequent UpuD
the readjustment to the double chromosome number. :
DESCRIPTION
The cytological account will begin with the telophase of the
heterotypic mitosis in the pollen mother cell. The ten figures in
plate XII are from the plant having 20 chromosomes, and were drawn
on a smaller scale than those of the other two plates. At this stage
the chromosomes can be counted with perfect accuracy. A large
number of counts of this telophase show that 10 chromosomes enter
each daughter nucleus. In a number of cases 10 were counted at each
end of the same spindle. In several instances 11 were found in one —
of the daughter groups, and in a few cases it was possible to show that
the corresponding daughter group contained only 9 chromosomes.
In this plant, then, there are 20 chromosomes which segregate into
two groups of ro each in the reduction division, one chromosome
occasionally going to the wrong group. Counts of somatic cells,
made long ago in tissues of the anther, also showed that 20 chromo-
somes were present.
_ The material from which the figures in plate XII were drawn was
subjected to an exceptionally high temperature in the process of |
imbedding, and in a few cases this has apparently affected the shape
of the viscous chromosomes. Figs. 1-5 are early telophases before
the formation of a nuclear membrane. In fig. 1 the chromosomes
nearly all show their bivalent nature, and in most of them the two
halves are dumb-bell shaped. This clubbing of the chromosome?
at the ends is a common phenomenon both at this time and in the
telophase ofthe homotypic and somatic mitoses. I have already
1909] GATES—CHROMOSOMES IN OENOTHERA 183
referred to these appearances in an earlier paper (9,‘p. 19). In jig. 2
the chromosomes are more irregular in shape, and their bivalent
character is not so evident. There are 11 chromosomes in the
daughter group, and examination of the adjacent sections showed that
there were g and no more at the other end of the spindle. The
globular black bodies seen in the figure are frequently found scattured
near the periphery of the cytoplasm. They stain like chromatin
with Haidenhain’s iron alum hematoxylin, but their chemical
nature is unknown. Figs. 3-5 each show 10 chromosomes. Fig. 6
is a telophase with 11 chromosomes, the next section showing 9 at
the other end of the spindle. Fig. 7 is an exact polar view, the
other figures being more or less oblique cuts of the spindle, but the
spindle fibers are not represented. Figs. 7, 8 are somewhat later
stages in side view, soon after the nuclear membrane is formed. Ten
chromosomes are present in each. In figs. 9, ro are shown in outline
the loop-shaped chromosomes of two somatic cells. Each has 20
chromosomes. ‘The cells are from the middle layers of the anther
wall.
Plates XIII and XIV deal with plants having 21 chromosomes.
Fig. 11 is a side view of the heterotypic spindle, showing 20 or 21
chromosomes. It is usually difficult to count the chromosomes
_ exactly at this time in a side view of the spindle, on account of the
close aggregation of some of them, and the presence of spindle fibers.
he chromosomes are almost never regularly oriented in an equatorial
plate on the heterotypic spindle. An examination of the literature
shows that in most plants and animalsa flat equatorial plate is formed
in the metaphase of this mitosis as in other mitoses, although a few
forms constitute exceptions. But the homotypic mitosis in Oenothera
has always a very definite equatorial plate, in which the chromosomes
are oriented in a single plane. There can be little doubt that the
irregularities in chromosome distribution arise from this failure of
the chromosomes to be regularly paired and oriented on the heterotypic
spindle. The irregularities in distribution certainly arise at this time.
I have recently confirmed practically all the events of reduction
by a study of the wild O. biennis, so that this account of reduction
applies to the genus Oenothera in general and is not the result of
mutative conditions. This will be referred to again later.
184 BOTANICAL GAZETTE [SEPTEMBEK
Fig. 12 is another cell in telophase. One nucleus is uncut, show- 3
ing 10 bivalent chromosomes. The other was sectioned by the knife. —
Fig. 13 shows 11 chromosomes and a number of very small nucleoli. —
Usually only one or two larger nucleoli are present. In fig. 14 there —
are 12 bivalent chromosomes. In such cases g appear at the opposite
end of the spindle. Figs. 17, 18 are very early telophases just after
the nuclear membrane has been formed. The daughter nuclei grow
very quickly to the size of figs. 19, 20, each of which shows 11 bivalent
chromosomes, while in the nucleus represented in fig. 21 there are
only 9. In general I have found that the nucleus having 9 chromo-
somes is likely to be appreciably smaller than one having 11. Evi- ©
dently the amount of karyolymph secreted by a nucleus is a function
of its number of chromosomes. This is also shown by the many cases
of single chromosomes left behind in the cytoplasm and forming small
nuclei during reduction, as observed in various forms, especially in
hybrids. :
These drawings of telophases are nearly all from nuclei which are
uncut by the knife in sectioning. The sections are usually 10 # thick,
so that in a majority of cases the nucleus is completely contained in
one section. The nuclear membrane is conspicuous; hence PY
focusing it can be determined with certainty that the membrane is
uncut and that the contents of the nucleus are intact. All the nuclei
in which counts have been made have been first shown to be intact
in this manner. Moreover, whenever the chromosomes in both
daughter nuclei could be counted, their sum was invariably found to
be 21, whether 10+ 11 or, as occurred in a few cases, 9+ 12:
There are a number of interesting features about the telophase,
which I have studied with particular care. In the first place it is 10
the best stage for counting the chromosomes with absolute accuracy,
and is even better than diakinesis, because of the reduced number
of chromosomes. In my last paper on reduction (11) I showed that
pairing before the reduction division only takes place to 4 limited
extent, and that the shapes characteristic of heterotypic chromosomes
are therefore usually absent at this time, as will be seen from figs:
26-34 of the paper referred to. During the period of interkines!>
however, the entire chromosomes of the heterotypic mitosis haviS
split to form bivalents in which the two parts are closely held together,
Wie te. ‘i
fa ia
ee, eee eet
1909] GATES--CHROMOSOMES IN OENOTHERA 185
show the characteristic X, Y, V, H, K shapes, etc. (See figs. 12-14,
19-21.)
A large number of counts of the chromosomes were made in these
telophases, and it was found that the numbers 10 and 11 occurred
_with approximately equal frequency, while the numbers 9 and 12 were
only occasional. Every single case which was admitted as a count
could be determined with absolute certainty as a case in which there
were, for instance, just 10 chromosomes, no more and no less.
In the anaphase of the heterotypic mitosis, the chromosomes as
they pass to the poles are nearly globular or somewhat elongated in
shape, and are at first closely massed at the poles of the spindle.
There is considerable variation in the time of appearance of the split in
these chromosomes, though they usually appear bivalent in the early
telophase. They appear to come into actual contact at this time,
forming a compact group, but never fusing or uniting. They very
soon begin to separate, however, and as they do so nuclear sap appears
between and to a lesser extent around them. Then the nuclear
membrane appears where the karyolymph comes in contact with
the cytoplasm. The nucleus so formed is at first very small, but
grows rapidly to its full size by the increase in nuclear sap.
Lawson (20) has described this process in detail in Passiflora
coerulea. He found that the chromosomes fused into a single mass
in the telophase, and that the karyolymph begins to be secreted
within this chromatic mass and later comes to surround it. The
cytoplasm, coming in contact with the karyolymph, forms the nuclear
membrane, which is therefore the limiting membrane of the cyto-
plasm, just as is the tonoplast of a vacuole. It is undoubtedly true
that the nuclear membrane is formed where the karyolymph comes
in contact with the cytoplasm, although it must remain uncertain
whether the karyolymph is secreted by the chromosomes Or merely
attracted and accumulated about them from the cytoplasm. There
must be extremely little if any cytoplasm included in the nucleus so
formed, because the nuclear membrane appears close about the
chromosome group when the chromosomes are still almost in contact.
This supports Gricore’s observations (14, 15), that the structural
contents of the resting nucleus are formed wholly from the chromo-
somes, and there can be no doubt, in this case at least, that the
186 BOTANICAL GAZETTE [SEPTEMBER
daughter nucleus is formed entirely from the chromosomes and the
karyolymph in which they float. This is to mea strong observational
evidence of chromosome continuity.
Unlike Lawson’s description for Passiflora coerulea, the chromo-
somes in Oenothera certainly do not fuse in the telophase of the
heterotypic mitosis, but maintain their separate identity completely
at first, and usually more or less completely thoughout the period of
interkinesis. Occasionally stages are found which indicate that they
string out and anastomose to some extent during a late stage of
interkinesis, partly losing their sharp boundaries, but this stage
apparently does not very often occur.
Nucleoli may be formed de novo in these daughter nuclei, as I
have described previously (8, p. 93). The chromosomes in this
telophase are all clearly bivalents, in which the halves are closely in
contact. I have examined thousands of nuclei in this stage and
have never seen the halves other than more or less closely in contact.
On the other hand, it is universally true in my observations that no
two chromosome bivalents are ever found in contact. Not only is
this the case, but they are invariably distributed at approximately
equal distances from each other, just within the nuclear membrane.
I have never seen an exception to this in any Oenothera studied.
The position of the chromosomes might be explained by supposing
that they are attached to the nuclear membrane from the first, and
are thus carried outward as the nucleus grows.5 In many cases the
chromosomes appear actually to be attached to the nuclear membrane,
or at least to be lying very closely against it. This, however, leaves
unexplained the fact that the chromosomes are never in contact with
each other at this time, and further that they are very generally
placed at approximately equal distances from each other, just within
the nuclear wall. All these facts point to the supposition that the
sIt might also be supposed that in the dehydration. processes prepaid :
m
mounting, the chromosomes would be drawn against the nuclear me
in such a case one would undoubtedly find the chromosomes occasionally massed
one side of the nucleus or irregularly placed, instead of being always at regular inte
vals about the periphery. _ From the regularity of their placing I have no doubt fis
the chromosomes occupy their original positions within the nucleus, and there is °
indication that they are ever disturbed by the processes of fixation, imbedding, ee
staining, when properly carried out. ;
TN
1909] GATES—CH ROMOSOMES IN OENOTHERA 187
chromosome bivalents are mutually repelled. It is true that in the
early telophase the chromosomes form a close group, so that they
certainly cannot be repelled at that time, but may be attracted.
However, the medium in which bodies float frequently changes their
qualities of attraction and repulsion, and it appears that the repul-
sion first develops after the appearance of the karyolymph in which
the chromosomes float. The facts all suggest that the chromosome
bivalents mutually repel each other at this time, while the halves of
these are held together, probably by attraction.
The studies of Witson (37) and others on insect chromosomes
show that there are selective attractions between certain chromo-
somes at the time of synapsis or at some other period of meiosis.
These of course require something more specific than electromag-
netic forces to explain them.
Fig. 22 shows one of the nuclei of a pollen mother cell in the pro-
phase of the homotypic mitosis. Eleven chromosomes are present,
_ having the same bivalent structure as in the telophase of the previous
mitosis. Both nuclei always go through the various stages of the
second mitosis simultaneously. The method of spindle formation
has not been studied with great care, but corresponds with the Gladi-
olus type of multipolar spindle formation (LAWSON 19, 21). There
is no indication of an intra-nuclear network, the spindle being wholly
extra-nuclear in origin. A portion of the weft of fibers surrounding
the nuclear membrane remains im situ when the latter disappears,
forming a close meshwork, against which the chromosomes lie. The
fibers then rearrange themselves; the fibrillae from the cones already
formed come in and become attached to the chromosomes; finally
the spindle becomes bipolar by the rearrangement of the fibers forming
the cones.
The numerous papers on spindle formation in angiosperms need
not be cited here. Among the more recent critical studies of this
structure may be mentioned that of BERGHS (2), who insists that the
distinction between kinoplasm and trophoplasm will not hold; that
the spindle results simply from the gradual orientation of the material
of the cytoplasmic reticulum, and returns to a reticulum after mitosis.
Sometimes spindle formation begins on one side of the nucleus,
as in fig. 23. In such cases the cones of the multipolar spindle may
188 BOTANICAL GAZETTE [SEPTEMBER
be formed and the nuclear membrane may have disappeared on one
side of the nucleus before any indication of spindle formation has
appeared on the other side.
Fig. 15 isa polar view of the two homotypic spindles in metaphase.
There are 11 chromosomes on one spindle and 1o on the other.
Fig. 25 is another at the same stage, showing 10 chromosomes. In
fig. 24 the spindles are at right angles and all the chromosomes are
not shown. In the side view of the spindle some of the chromosomes
appear like tetrads, owing to their bivalent structure. On the homo-
typic spindle, before the chromosomes divide, they are very regularly
oriented in a single plane in the equatorial plate, as in jigs. 15; 25-
This contrasts strikingly with the heterotypic spindle, in which the
chromosomes are scattered for a considerable distance along the
long axis of the spindle, so that there is usually no metaphase, strictly
speaking.
Fig. 26 is an early anaphase of the homotypic mitosis, showing
one spindle in side view and one in polar view. In the polar view
20 chromosomes are found by focusing through a short distance, and
the remaining 2 are found on the next section. In the side view the
chromosomes could not all be counted, but presumably there were
20 after division. Two pale-staining nucleoli still persist in the
cytoplasm.
Fig. 16 shows three of the nuclei in the telophase of the homotyp!¢
mitosis. Many of the chromosomes have a characteristic two-lobed
or dumb-bell shape. One chromosome is left behind in the cyto-
plasm, leaving ro chromosomes each in two of the daughter nuclel.
This two-lobed shape is a characteristic appearance of the chromo-
somes in the telophase of somatic mitoses, but presumably bears no
relation to the next mitosis, because if this were the beginning of a
split for the next mitosis it would indicate that the division of the
chromosomes is transverse. But metaphase and anaphase stag® of
somatic mitoses show that the chromosomes divide longitudinally.
Of course the possibility that the transverse axis of a chromosome
in telophase should regularly become its longitudinal axis before the
next metaphase, is not excluded, although this seems unlikely.
The great difference in the size of the figures made it impossible
to arrange them in order on the plates. The magnification is the same
OO Se ed eee Ea Lee ere et tena
1909} GATES—CHROMOSOMES IN OENOTHERA 189
as in my last paper in this journal (11), so that the figures can be
directly compared.
DISCUSSION
The history of any ontogeny is the history of the transformation
of chemical metabolism into definite structures, or rather the eventua-
tion of a series of chemical processes in the production of a series of
physical structures. Morphologists and cytologists map the succes-
Sion of structures appearing and call it a series of events. They are
not unmindful, however, that the primary process is the metabolism,
the structures its by-products, which in turn, so far as they are ca-
pable of continuing metabolism, produce other structures and, par-
ticularly in the adult organism, structures like themselves. Similarly,
the chromosomes of the germ nuclei must be thought of as definite
aggregations of chemical materials, which initiate or take part in
certain forms of metabolism. The chromosomes themselves do not
(at any rate not wholly) control their growth or division, but this is
more or less subject to the conditions of temperature, etc., in which
they are placed, as the work of ERDMANN (7) and others has shown.
Similarly, as the complex of physical and chemical conditions in the
nucleus and cell undergoes changes, the chromosomes change from
the compact to the alveolate or distributed condition, or vice versa,
etc. The cytologists who record these events are aware that chemical
transformations are continually going on, and that the changes in
Visible physical structures are the external concomitant of such chem-
ical processes.
Chemical reactions in the test tube, however complex, do not lead
to the production of any structures more complex than crystals or
flocculent masses of various sorts. There are indications that living
matter frequently has the properties of liquid crystals, but why do
the infinitely more complex reactions of living matter build structures
of such relative permanency and of tremendous intricacy? The
problem of individual development, from this standpoint, is the ques-
tion, How do certain forms of chemical metabolism result in the
Production of certain visible physical structures or characters? Of
Course, our present microscopic appliances do not permit us to know
how many structural steps, if any, there may be between the inter-
acting molecular masses and the finest structures visible under our
190 BOTANICAL GAZETTE [SEPTEMBER |
highest powers, but it is by no means necessary to assume that there
are such. This digression will indicate to some extent, perhaps, the
viewpoint of the writer in connection with the cytological aspects of
this work.
No attempt will be made to discuss here the literature of reduction,
only a very few of the recent papers being referred to. The discus-
sion of matters of cytological detail will be taken up at another time.
One important matter, which was discussed in a former paper (11),
concerns the method of chromosome reduction, i. e., whether there
is a pairing of threads about the time of synizesis and whether the
spirem afterward breaks into a single series or two parallel series
of chromosomes. In the paper referred to I established the fact
(as will be conceded, I think, after a study of figs. 20-32, particularly,
of that paper) that the spirem breaks into a single and not a double
chain of chromosomes. The possibility of finding a series of stages
which really demonstrates this depends on the shape of the chromo-
somes in Oenothera. They are relatively short and thick, like many
animal chromosomes, and quite unlike the twisted and tangled
chromosomes of such forms as Lilium, whose relationships are 5°
difficult to interpret. It is a curious fact that so many of the critical
studies on reduction in plants have been made on forms with long
narrow chromosomes, although many of the interpretations of critical
stages can be made with much greater ease and certainty on forms
having short and stout chromosomes.
In the paper just referred to, I concluded that the method was
probably different in different genera, there being a side-by-side
pairing of threads in some forms (parasynapsis),° but an end-to-end
arrangement of the chromosomes to form a single spirem (telo-
synapsis)° in other forms. Subsequent papers by various invest-
gators continue to describe both these methods, and the evidence 9
certain cases is so clear that I think there can remain no doubt that
both these general methods occur in plants. MONTGOMERY concluded
in 1898 (26) that there are different types of reduction in animals.
In a recent study of Fucus, Yamanoucut (39) shows clearly that
at the time of reduction the ragged nuclear reticulum is gradually
transformed into a single continuous thread, which enters into
6 These convenient terms follow the usage of Witson (36).
1909] GATES—CHROMOSOMES IN OENOTHERA IQI
synapsis. This thread then becomes rearranged into regular loops
converging to one side of the nucleus and forming the “bouquet”
stage of E1sEN (6). This stage is characteristic of many animals,
in which it has been described by JANSSENS and DuMEz (17), STEVENS
(34, 35), MARECHAL (25), and JorDAN (18), to mention only a few.
Each loop is composed of two chromosomes arranged end to end.
Similarly the spirem in Fucus is made up of the maternal and paternal
chromosomes arranged endwise in a single thread. This is what I
have shown to be the case in Oenothera (11), although Oenothera
has no typical “bouquet” stage, nor has any other angiosperm, so
far as I am aware, though the second contraction phase, character-
istic of various forms, probably corresponds to it. OVERTON (30)
states that this stage does not occur in the plants with short chromo-
somes which he has examined, yet it occurs in Oenothera, in which
the definitive chromosomes are very short and frequently almost
globular. The second contraction phase is a well-marked stage of
meiosis in Oenothera.
I may mention a few of the recent accounts involving an end-to-
end arrangement of the chromosomes to form the spirem (telo-
synapsis). Morrtrer finds (29) that in Podophyllum, Lilium, and
Tradescantia the two members of each bivalent chromosome were
not side-by-side in the spirem, representing the halves of the longi-
tudinally split thread, but were arranged end-to-end in the chromatic
thread. Lewis (22), in a study of Pinus and Thuja, finds no pairing
of threads, but cross-segmentation of a single post-synaptic spirem to
form the chromosomes. Just what relation his fig. 15, which indi-
Cates a reticulum as occurring about the time of chromosome forma-
tion, bears to the other stages, it is hard to say. Lewis ventures the
Opinion that the second division is probably qualitative, but with a
manifest lack of evidence to support it. SCHAFFNER (33), in Agave,
nds bodies which he believes are bivalent prochromosomes, and a
Single spirem which segments to form the twelve bivalent chromo-
somes.
Among very recent accounts of reduction which involve a longi-
tudinal pairing of threads (parasynapsis) may be mentioned that
of Grécore (16), with figures involving the critical stages in Lilium,
smunda, and Allium; YAmMaNoucut (38) in Nephrodium; OVER-
192 BOTANICAL GAZETTE [SEPTEMBER
TON (30) in Thalictrum, Calycanthus, and Richardia. ALLEN’S
extensive earlier paper on Lilium (1) should also be mentioned.
Although, in such cases as Lilium, both accounts of reduction are given
for the same form by different authors, yet the evidence from such
forms as Nephrodium on the one hand, and Tradescantia, Oenothera,
and Fucus on the other hand, makes it very difficult to deny that both
methods occur. A comparison of a wide range of forms whose reduc-
tion phenomena show many differences, will doubtless lead finally
to an explanation of the nature and meaning of these differences. It
is very evident that the time has passed when all the accounts of
reduction in plants can be brought under a single scheme. The task
of the future will be to interpret the meaning of the differences
observed in various forms. Are they matters merely of cell mechanics,
or are they related to hereditary processes? It is not impossible
that correlations will be found between the method of reduction in an
organism and its type of hereditary behavior. In other words, the
phenomena of reduction and the distribution of elements during
meiosis may condition to some extent the hereditary behavior of a
plant or animal. This is already known to be the case with sex in
insects. But it does not seem worth while entering into such theoret-
ical possibilities on the basis of our present knowledge.
The fact that in this Oenothera hybrid the number of chromosomes
in the pollen mother cells is the sum of those which enter the fusion
nucleus at the time of fertilization, is to me clear evidence that each
chromosome in the germ cells is the genetic descendant of one of the
chromosomes in the fertilized egg. The work of various investigators
seems to have established the genetic continuity of chromosomes from
generation to generation of individuals. ‘The manner in which the
chromosomes are distributed during reduction in this Oenothera
hybrid clearly shows that they behave as individuals at this time.
Witson’s recent account of the supernumerary chromosomes ei
Metapodius (37), a genus of Hemiptera, shows certain points ©
resemblance to the condition in Oenothera. WILSON finds that
certain chromosomes (the idiochromosomes) may be present in duplt
cate, or may even have several representatives in the cells of certain
individuals, which nevertheless show no external difference> ”
number of chromosomes being fixed for any individual, but vary
1909] GATES—CHROMOSOMES IN OENOTHERA 193
in different individuals from 21 to 28 according to the number of
supernumerary chromosomes present. The distribution of the super-
numeraries during spermatogenesis is also irregular, so that the num-
ber varies in the different sperm nuclei of an individual. Occasional
irregularities in the distribution of idiochromosomes during reduction
were observed in the form having 22 chromosomes, both idiochromo-
somes passing to the same cell. This is believed to be the origin of
_ Ue variation in different individuals, the supernumeraries being
| merely duplicates of the idiochromosomes.
Similarly, I have observed occasional irregularities in the chromo-
some distribution during reduction in nearly all the mutants of
_ Oenothera examined, and this doubtless accounts for the different
_ humbers of chromosomes found in different individuals, the extra
chromosomes being duplicates of others already present, and the
presence of 20 chromosomes in one individual of O. lataXO. gigas
being due to the absence of one chromosome from one of the germ cells
Which produced that individual.
_ Montcomery (27) first proposed the theory that in synapsis
homologous chromosomes of maternal and paternal origin pair with
each other, and much subsequent work, especially with animal
chromosomes, sustains that view. As I have already shown, pairing
of Oenothera chromosomes frequently fails to take place, and this
allows a chance for the irregularities in chromosome distribution
4 Which occur. Boverr (3, p- 54) has suggested that when there is an
_ absence of pairing in synapsis in any organism, its chromosomes are
hereditarily equivalent. In Oenothera there is clearly a tendency to
pair, but it is only partly carried out. I have already compared (11,
_ P- 25) the behavior of the chromosomes in this hybrid with the con-
7 dition described by ROSENBERG (31) in the Drosera hybrid having
o+20 chromosomes. The method of segregation of chromosomes
_ In the heterotypic mitosis is evidently different in the two hybrids,
4nd this was used as an argument in favor of a different method of
Teduction in the two cases. In the Oenothera hybrid the 10-11
Segregation shows that the segregation cannot be between chromo-
Somes of maternal and paternal origin, but it must be remembered
_ im this connection that the 14 paternal chromosomes are very prob-
a ably a double set of 7 O. Lamarckiana chromosomes. The regu-
194 BOTANICAL GAZETTE [SEPTEMBER
larity with which the ro-rz segregation takes place, indicates that
it is not merely a matter of chance, but that some mechanism, perhaps
connected with the spindle, determines this regularity. A study of
later generations of this hybrid should throw much light on the ques-
tion whether the chromosomes of Oenothera are really unlike.
Morcan (28) has recently shown that in certain phylloxerans,
in which a generation of winged individuals produces (partheno-
genetically) sexual males and females, the eggs are of two kinds, the
female-producing eggs being large and the male-producing eggs
small. Further, the females thus produced have the same number
of chromosomes as the parthenogenetic females, while the males
have two chromosomes less. Thus, in the formation of the polar
body of the male egg, two extra chromosomes are extruded, so that
the somatic cells of the male contain two less chromosomes than those
of the female. Evidently there is here some sex-determining factor
which antedates the chromosomal differences with the two kinds of
eggs, and yet the chromosomes are the instruments of this factor,
for the extrusion of the two chromosomes always precedes the develop-
ment of the male individual. Studies of this sort will doubtless g!v°
us clearer notions regarding the respective réles of chromosomes
and cytoplasm in heredity. :
In a former paper (11) I suggested that if the chromosomes of
Oenothera are unlike in their hereditary capacities, then the occa-
sional irregularities I have described in the chromosome distribu-
tions on the heterotypic spindle would furnish a possible basis for the
appearance of a series of types, such as the mutants of O. Lamarckian4.
I have since studied the reduction phenomena in O. biennis an
other types, an account of which will be published later. O. biennt’,
in at least some of its geographical races, appears to be stable und ef
ordinary conditions, though MacDouGat (24a) has obtained atypl@
forms by injections into its ovaries. The loose and frequently
unpaired arrangement of the chromosomes in the central region. of
the heterotypic spindle is evidently a delicately adjusted condition
which can easily be thrown out of balance. Yet in some way te
balance is ordinarily maintained and is only occasionally deranged
in such a way that a different chromosome distribution results. It =
not impossible that the condition of mutation in O. Lamarckian4
ER TT a eee ee ee Re, Oe et 2 aves) ee? ee) ea ws Cee,
BSEe, ree IPE ego mee Rae Ae Phe ey
re OM RET CVE S See ea oh ho PP ee, Se ee Ae ee Ps ee epee hemot, Wp
a, Fran we ee as ee ae ‘eet eet ae i
1909] GATES—-CHROMOSOMES IN OENOTHERA 195
has arisen through a disturbance by some means of this delicate con-
dition of balance. 5
But it is useless to speculate on such possibilities until it is known
_ whether the chromosomes of Oenothera are really unlike, and at
present there is no evidence in favor of this view except the inferential
evidence from chromosomes in general. The fact that chromo-
somes reappear with each mitosis, showing the same differences
where visible differences exist (except in the cases of amitosis, whose
_ Status in relation to hereditary processes is not at present understood),
_ would seem to favor the assumption that they maintain their identity
_ and are unlike. But I need not cite here the general arguments in
_ favor of this hypothesis. ‘The more definite evidence, such as that of
the sex chromosomes in insects, is not necessarily of universal applica-
tion.
SUMMARY
1. O. lataXO. gigas has 21 chromosomes in its somatic cells, 7 of
maternal origin (O. /atd) and 14 of paternal origin (O. gigas). In
one individual the number was 20, owing probably to the absence
_ of one chromosome from one of the germ cells which produced this
individual.
2. These chromosomes segregate at the time of reduction, so that
in individuals having 21 chromosomes half the germ cells receive 10
and half 11 chromosomes. In the individual having 20 chromosomes,
Io enter each germ cell. Occasionally one chromosome goes to the
_ Wrong pole of the spindle, so that in plants having 21 chromosomes
a few germ cells are found having 9 or 12 chromosomes and in the
plant with 20 chromosomes, occasional germ cells have 9 or 11
Rade etre Mipkyes 8
} ion accounts
chromosomes. This irregularity in d
for the fact that different individuals in a race in some cases have
different numbers of chromosomes.
3. The 10-11 segregation of chromosomes in the formation of the
8erm cells of this hybrid shows that there is not here a pairing and
S€paration of homologous chromosomes of maternal and paternal
Origin, but that the segregation tends to be into two numerically
_ €qual groups.
Bir
ee
~<
4. Evidence from this and other work shows that there are two
general methods of chromosome reduction in plants, one involving
196 BOTANICAL GAZETTE [SEPTEMBER
a side-by-side pairing of chromatin threads (parasynapsis) to form a
double spirem; the other involving an end-to-end arrangement
(telosynapsis) of the maternal and paternal chromosomes to form
a single spirem, which may afterward split longitudinally.
5. The behavior of the chromosomes in Oenothera supports the
view of their genetic continuity from generation to generation, the
number present in any individual being always the sum of the chromo-
somes in the germ cells from which that individual was formed.
6. If the chromosomes of Oenothera are unlike in their hereditary
capacities their behavior furnishes a not improbable basis for the
phenomena of mutation in Oenothera Lamarckiana. But it remains
to be proven that the chromosomes of Oenothera are of unequal
hereditary value.
THE UNIVERSITY OF CHICAGO
LITERATURE CITED
1. ALLEN, C. E., Nuclear division in the Aspe mother cells of Liliwm canadense.
Annals of Botiaty 19: 189-258. pls. 6-9. 1905.
. Bercus, J., Le fuseau hétérotypique de Paris quadrifolia. La Cellule 22:
203-214. pls. 2. 1
Boveri, T. echuie iiber die Konstitution der chromatischen Substan?
des Peltier, pp. 130. figs. 75. Jena. 1 d
, Zellen Studien V. Ueber die Abbingigkeit der Kerngrésse uD
Zellenzahl des Seeigel-Larven von der Chromosomenzahl der Ausgangszellen.
pp. 80. pls. 2. figs. 7. Jena.
5. DeVries, H., Bastarde von ecahien gigas. Ber. Deutsch. Bot. Gesells.
26a: 754-762. 1908.
. Etsen, G., Speimstogenesis of Batrachoseps. Journ. Morph. 17: i
pls. 14. 1900.
ErpMANN, R., Experimentelle Untersuchung der Massenverhiltnisse vo?
P a, Kem, und Chromosomen in dem sich entwickelnden Seeigelei.
Arch. Zellforsch. 1:76-136. 1908. ee
8. Gates, R. R., Pollen development in hybrids of Oenothera lata XO. Lama
kiana, and its feisGen tomutation. Bor. GAZETTE 43:81-115- pls. 2-4- er
, Hybridization and germ cells of Oenothera mutants. Bot. GazeTTe
i)
Y
a
i
44: 1-21. figs. 3. 1907. ; vt
10. e chromosomes of Oenothera. Science N. S. 27: ease
Ir s study of reduction in O¢enothera rubrinervis. BOT
46: sag pls. 1-3. 1908.
yon
. GEerTs, J. M., Beitrage zur Kenntnis der cytologischen Entwicklung
Oenothera Pomatchlen Ber. Deutsch. Bot. Gesells. 26a:608-614- *
Lal
N
Cth eee eee eee
1909] GATES—CHROMOSOMES IN OENOTHERA 197
13.
al
eS
Leal
un
4
~J
24.
Geerts, J. M., Beitrige zur Kenntnis der Cytologie und der partiellen Ster-
ilitat von Oenothera Lamarckiana. Recueil Trav. Bot. Néerl. 5:93-208. pls.
5-22. 1909.
. Grécorre, V., ET Wycaerts, A., La reconstruction du noyau et la formation
des chromosomes dans les cinéses somatiques. La Cellule 21:7-76. pls.
. Grécorre, V., La structure de l’élément chromosomique au repos et en divi-
sion dans les cellules végétales (racines d’Allium). La Cellule 23: 311-353.
jigs. 3. pls. 2. 1
6.
go
, La formation des gemini hétérotypique dans les végétaux. La Cel-
lule 24: 369-420. = 2:
1907.
. Janssens, F. A., Et Dumez, R., L’élément nucléinien pendant les cinéses
de maturation de sperinadagtes chez ee attenuatus et Pleto
La Cellule 20: 421-460. pls. 5
- Jorpan, H. E., The abe aie asi oe A pops Mayeri. Carnegie Institu-
tion Srp 102. pp. 13-36. pls. 1-5
. Lawson, A. A., Origin of the cones of multipolar spindle in Gladiolus.
Bor, Gazetre 30: 145-153. pl. 12. 1900.
———.,, On the relationships of hs nuclear membrane to the protoplast.
Bor. Gazette Sg 305-319. pls. 1903.
, Studies in spindle msde Bot. GAZETTE 36:81-100. pls.
15, 16. 1904.
. Lewis, I. M., The behavior of the chromosomes in Pinus and Thuja. Annals
of Botany 22: 529-556. pls. 29, 30. 1908.
. Liu, F. R., Observations and experiments concerning the aero |
piece of embryonic development in Chaetopterus. Journ. Exp.
3°153-268. pl. r. figs. 78. 1906.
Lutz, ANNE M., Notes on the first generation hybrid of Ocenothera latax
O. gigas. Science N. S. 29: 263-267. 1909.
24a. MacDovuaeat, D. T., Vari, A. M., AND SHULL, G. H., Mutations, variations,
i]
Oo
a)
°
and relationships of the Oenotheras. Carnegie Institution Publ. 8. pp. 92.
pls. 22. figs. t
MarécHar : “fur es 76 ese des Sélaciens et de quelq utres Chordates.
i ka Cellule 24: 7-239. pls. I-II. 1907.
. Montcomery, T. H., The spermatogenesis in Pentatoma up to the formation
of the spermatid. Zool. Jahrb. Anat. Ont. r2/1-88. pls. 1-5. 1
——., A study of the chromosomes of the germ cells of Metazoa. "Trans.
Amer. Phil. Soc. 20: 154-236. pls. 4-8. 1901.
- Morcan, T. H., Sex determination = a in phylloxerans and
aphids. Siienes: N. S. 29: 234-237-
- Morrter, Davip M., The bainedeihis tig the heterotypic chromosomes In
pollen thother cells. Anas of Botany 21: 309-347: pls. 27, 28. 1907-
- Overton, J. B. On the organization of the nuclei in the pollen mother cells
of certain plants with especial reference to the permanence of the o-
Somes. Annals of Botany 23:19-61. pls. 1-3. 1909-
198 BOTANICAL GAZETTE [SEPTEMBER
31. ROSENBERG, O., Ueber die Tetradentheilung eines Drosera-Bastardes. Ber.
Deutsch. Bot. Gesells. 22: 47-53. pls. 4. 1904.
32. ———, Cytological studies on the apogamy in Hieracium. Botanisk Tids-
skrift 28: 143-170. figs. 13. pls. 1, 2.
33. SCHAFFNER, JoHN H., The fe daciioe Bvisinn in the 2 of
Agave virginica. Ren GAZETTE 47: 190-214. pls. 12-14. 9.
34. Stevens, N. M., Studies in spermatogenesis, with special Bes to the
accessory chromosome. Carnegie Institution Publ. 36.% pp. 32. pls. 7. 1998.
: omparative study of the heterochromosomes in certain species of
eee Hemiptera, and Lepidoptera, with especial reference to sex deter-
mination. Carnegie Institution Publ. 36.2 pp. 33-74. pls. 8-15. 1906.
. Witson, E. B., Studies on chromosomes. IV. Journ. Exp. Zool. 6:84.
1909.
w
an
, Studies on chromosomes. V. The chromosomes of Metapodius.
Journ. ‘ey: Zool. 6: 147-205. pl. r. figs. 13
38. YAMANOUCHI, SHIGEO, Sporomeesis i in S ceecoatew. Bor. GAZETTE 45:1-
30. pls. 1-4. 1908.
, Mitosis in Fucus. Bot. Gazette 47:173-197. pls. 2-11. 1909-
EXPLANATION OF PLATES XII-XIV
The figures were drawn with the - of a Bausch & Lomb camera anda Zeiss
apochromatic objective 2™™, an. 2. particular care being taken to ere
the chromosomes accurately. The ‘etic in plate XII were drawn W! ye
Zeiss compensating ocular 12, those of plates XIII and XIV with ocular 18. :
are reduced one-fourth in reproduction, which leaves the figures in plates ae
and XIV magnified as in my last paper (11) on reduction.
PLATE XII
All figures from the plant having 20 chromosomes. cells
Fic. 1.—Early telophase of the heterotypic mitosis in the pollen mother t:
before formation of the nuclear membrane; 10 chromosomes, all ae bivalen
in many the halves are dumb-bell sha at
Fic. 2.—Same stage; 11 chromosomes, many irregular; 9 chromosomes
the opposite end of this spindle; dark staining bodies in saicbeed of cytoplas™-
Fic. 3.—Telophase, showing 10 chromosomes of various shapes. pe
a 4.—Telophase, showing 10 chromosomes, most of them clearly bivalen
eicsne f their
is. 6.—Telophase, downs rr chromosomes, with no indication © Bs
bivalent character; 9 at opposite end of spindle; apparent size of chrom
in all figures varies to a certain extent according to the depth of stain. pee
Fics. 7, 8.—Later telophases, soon after formation of nuclear membrane,
showing 10 chromosomes. ddle
FIGs. 9, 10.—Metaphase groups of chromosomes in somatic cells from ™!
layers of anther wall, each showing 20 chromosomes; indications of a” asi
ment of the chromosomes in pairs.
® BOTANICAL GAZETTE, XLVIII PLATE XII
GATES on CHROMOSOMES of OENOTHERA
NOTANICAL GAZETTE, XLVIII PLATE XIII
GATES on CHROMOSOMES of OENOTHERA
MeMOFANICAL GAZETTE, XLVIII PLATE XIV
GATES on CHROMOSOMES of OENOTHERA
1909] GATES—CHROMOSOMES IN OENOTHERA 199
PLATE XIII
Figures in plates XIII and XIV from plants having 21 chromosomes; not
numbered in developmental order.
Fic. 11.—Heterotypic spindle in side view, showing 20 or 21 chromosomes,
not forming an equatorial plate, but loosely aggregated in the median region of the
spindle; cf. fig. 15. ;
Fic. 12.—Telophase of heteroptypic mitosis, showing both daughter nuclei;
one, uncut, shows 10 chromosomes.
Fic. 13.—Telophase, showing 11 chromosomes and a number of very small
nucleoli; an unusual condition, probably due to the failure of the nucleoli to
fuse at an earlier stage.
Fic. 14.—Telophase, showing 12 bivalent chromosomes, lying closely against
the wall, tipped at various angles to the plane of view, which gives them a variety
of appearances; an exceptional case, in which one chromosome too many has
passed to the end of the spindle; 9 at opposite end; 2 nucleoli.
Fic. 15.—Metaphase of homotypic mitosis in polar view, showing equatorial
plates of chromosomes, 10 chromosomes on one spindle and 11 on the other;
ef. fig. rr.
PLATE XIV ;
Fic. 16.—Telophase of homotypic mitosis, showing three daughter nuclei;
one chromosome left behind in the cytoplasm, leaving 10 chromosomes each in
two of the daughter nuclei; many chromosomes show characteristic dumb-bell
shape.
Fics. 17, 18.—Very early telophase of the heterotypic mitosis, just after the
nuclear membrane has been formed around the daughter nuclei; one shows to
bivalent chromosomes, the other 11.
Fics. 10, 20.—Telophases, each showing 11 bivalent chromosomes.
Fic. 21.—Telophase with 9 chromosomes only.
Fic. 22.—Prophase of the homotypic mitosis, showing 11 bivalent chromo-
somes, which have th pr in the previous telophas ; nuclearmem-
brane just broken down, its position still occupied by a weft of fibrillae, against
which the chromosomes lie; cones of the multipolar spindle forming. eae
Fic. 23.—Same stage as fig. 22; a less common condition, in which spindle
formation begins on one side of the nucleus; 10 chromosomes, only a few of
which show bivalent character. is MEE
_ Fic. 24.—Metaphase of the homotypic mitosis, showing one spindle in side
view and the other in polar view; chromosomes not all shown.
__ Fic. 25.—Equatorial plate of homotypic spindle, showing 10 chromosomes
in a single plane, few showing their bivalent character. es
1G. 26.—Early anaphase of homotypic mitosis, after division ine babl
Somes; one spindle in side view, showing only part of the chromosomes agamersed
20 in all); the other spindle in polar view, showing 20 chromosomes (two more
8 "5 this spindle in the next section); 2 nucleoli in the cytoplasm near
Spindles,
THE DEVELOPMENT OF THE EMBRYO SAC OF
SMILACINA STELLATA
F. McALLISTER
(WITH PLATE XV)
The object of this paper is to describe the development of the
embryo sac of Smilacina stellata (L.) Desf., with a view to its pos-
sible bearing on the current interpretations of the lily type of embryo
sac. :
In 1880 TrEUB and MELLINK (27) reported that in Lilium bulbi-
ferum and in Tulipa Gesneriana the embryo sac mother cell develops
directly into the embryo sac without any previous divisions.
In 1884 GUIGNARD (11) and also STRASBURGER (24) called atten-
tion to the fact of a reduction of the number of the chromosomes
during the development of the germ cells of angiosperms. STRAS
BURGER (25) further pointed out in 1888 that in the case of the
embryo sac in certain orchids and in Allium, the reduction of the
number of the chromosomes occurs in the nucleus of the embry?
sac mother cell.
It was further established simultaneously by OVERTON (16) and
GurGNaRD (12) that, in the lilies and other plants in which the embry°
sac mother cell develops directly into the embryo sac without previous
division, reduction takes place in the nucleus of the young embry?
sac. The natural conclusion from these discoveries is that the yours
embryo sac in these cases is the morphological equivalent of a pollen
or embryo sac mother cell. That the nuclei resulting from the first
two divisions in the embryo sac of the lilies are morphological equiv
lents of the microspores is strongly suggested by these results.
STRASBURGER (26) in 1894, discussing the formation of the a
sac of the lilies, concludes that the cell in which the reductio? 0.
the chromosome number takes place is to be regarded as 4 mother
cell and not simply as a young embryo sac, since in the ovaries °
Allium and Helleborus he had found that the reduction of vd
chromosomes takes place in the embryo sac mother cell before. sags
* Botanical Gazette, vol. 48] aa
1909] MCALLISTER—EMBRYO SAC OF SMILACINA 201
undergone division. He concludes that in these cases the course of
development is abbreviated, so that there is no formation of reduced
cells which are to be immediately absorbed, as is the case in many
other species. According to this view the heterotypic and homeotypic
divisions are transferred to the early stages of development of the
gametophyte.
The term “macrospore” or “megaspore” is frequently loosely
used by the supporters of this view in reference to the cell which
develops into the embryo sac, whether it be the young embryo sac
itself, or one of the daughter cells, or one of four granddaughter cells
which have been formed by the reduction divisions.
From the evident homology of the nuclei of the first two divisions
of the embryo sac mother cell of the lilies with the microspores, as
Suggested by the discoveries of GUIGNARD, STRASBURGER, OVERTON,
and also later investigators, the obvious interpretation of their nature
is that they are megaspores. According to this view the reduction
divisions may be regarded as the sole criteria of spore formation.
STRASBURGER (26) further says, in reference to the significance of
the number of divisions which intervene between the embryo sac
mother cell and the completed embryo sac, with its egg: “That the
number of these intervening divisions is not of primary importance is
Proved by the fact that the number is not always the same: thus in
Lilium and Tulipa there are but three; in Ornithogalum, Com-
melyna, and species of Agraphis, there are four; in yet other cases the
number jis greater than five. ... . ”
Smilacina stellata, the species which I have studied, is a member of
the order Convallariaceae. The data as to the morphological relation-
ships of the genus Smilacina are scanty and in part contradictory. The
order Convallariaceae is retained by ENGLER and PRANTL under the
sroup Asparagoideae, but the nature of the relationship of the group
'o the other orders of the Liliales is not very clear. The other mem-
bers of the Convallariaceae whose embryo sac development has been
Studied are Convallaria, Paris, and Trillium.
Convallaria majalis has been investigated, as to the development
of its embryo sac, by WIEGAND (29). He reports that the embryo
‘ac mother cell divides to form two fully separated daughter cells,
the outer of which is the larger. The nuclei of both of these cells
202 BOTANICAL GAZETTE [SEPTEMBER
undergo a second division, but this time no cell walls are formed.
The resulting four nuclei again divide, and the partition wall between
the two sets of nuclei disintegrates enough to allow a nucleus from the
lower set to pass through and unite with one from the upper set. This
fusion nucleus is the endosperm nucleus. If this account is correct,
we have at least a partial absorption of a cell wall in the formation
of the embryo sac and the utilization of all four nuclei of the double
division, as will be described below for Smilacina stellata.
WIEGAND’s account is contradicted, however, by SCHNIEWIND-
Tutes (21), who reports that in Convallaria majalis the mother cell
divides to form a row of four cells, one of which develops into the
embryo sac, while the other three disintegrate. As a possible explana-
tion of the difference which exists between her account and WIE-
GAND’s, she remarks that’ greenhouse material rarely shows normal
development. WrEGAND, however, does not mention the use of such
material in his investigation. That both Wrecanp and SCHNIE-
WIND-THIES are correct is possible, but not very probable. It 1s
very much to be desired that this species be reinvestigated to clear
up this confusion.
ERNST (9) reported that in Paris quadrifolia the lower of two
daughter cells develops into the embryo sac. The upper daughter
nucleus divides once, but the resulting nuclei degenerate. In the
same paper he reports that the lower of two daughter cells of T rillium
grandiflorum develops into the embryo sac. The upper daughter
cell is smaller from the first and rarely divides. For T. recurvatum, OP
the other hand, CHAMBERLAIN (6) has reported that the embry° sac
develops from the lower of four megaspores.
Though scanty, the literature on the order Convallariaceae pes
to suggest that there exists in the group great variation in the condu
of the cells and the nuclei resulting from the reduction divisions, an |
that we may here find transition conditions between the
normal type of embryo sac formation and that found in the lily.
The materials for this study were collected in the vicinity of Be
Wis., in May 1906 and 1907, in November 1907, and in June uae
Flemming’s strong solution gave the best fixation for the early at
but worked badly for mature embryo sacs. With these ™ ee
embryo sacs the following chromacetic fixative gave good res
oit,
1909] MCALLISTER—EMBRYO SAC OF SMILACINA 203
chromic acid 0.7%, glacial acetic acid o.5°°, water 100°°. A fixative
composed of two parts absolute alcohol and one part glacial acetic
acid gave very good results also. Flemming’s weak solution was not
tried.
Smilacina stellata is especially favorable for obtaining a complete
series of stages of the early development of the embryo sac. The
flowers, eight to fourteen in number, are borne in a raceme, which
does not expand till the embryo sac has nearly reached the eight-
celled stage. It is therefore possible to cut an entire’ raceme longi-
tudinally and get a maximum number of ovules cut parallel to their
long axes. The oldest flowers are at the bottom. Each flower con-
tains five to seven ovules, and about seventy racemes were cut in
paraffin. ; i
In the material collected November 16, the nucellus was only
partly developed in the lower flowers of the raceme. There were
no mother cells to be distinguished in any of this material. Material
collected May 7 showed, in a few shoots, mother cells in the synapsis
stage in the lower flowers, while at the top of the shoot the nucellus
was barely differentiated. Most of the racemes taken at this date
Were farther developed: than those mentioned above, the younger
flowers being at least in the synapsis stage.
The mother cell is located at a variable depth beneath the surface
of the nucellus. Not uncommonly it is immediately beneath the
epidermis (fig. 1). In other cases it is separated from the epidermis
by one cell layer. Most commonly two cell layers intervene (fig. 2).
Measurements of several camera drawings of the mother cell at the
Synapsis stage gave an average breadth of 22 #, and an average length
of 30 Bb. ’
I shall not here take up in detail the question of the reduction of
thechromosomes. In the first division of the mother cell, thick double
chromosomes, characteristic of the metaphases of the heterotypic
division, appear (fig. 3). The number of bivalent chromosomes,
as shown in the anaphase stage of this division, is twelve. The
‘porophytic number, as shown by root tip cells, is twenty-four. -
A definite cell plate, and in most cases a cell wall, is formed,
Separating the two daughter nuclei of the first division before the
‘econd division takes place (figs. 4, 5). The cell plate is formed by
204 BOTANICAL GAZETTE [SEPTEMBER
the thickening of the connecting fibers in the equatorial region to
form a septum which separates the cells. This splits in the central
region first, and often a thin layer of orange staining material is to
be seen between the split layers. The plasma membranes formed
by the splitting of the cell plate are made very conspicuous in cells
in which there is a slight plasmolysis. The cell wall seems in most
cases to be fully formed before the second division is completed.
Several preparations were found in which the wall seemed to be
incomplete after the second division (jig. 7). These, however, may
represent a stage in the removal of the cell walls, as described
below.
In many cases the wall of the first division is transverse, but not
infrequently it is oblique (figs. 4, 12). The walls formed in the second
division are extremely variable as to their position. F requently
(fig. 11) they are transverse, forming a linear row of four cells.
Very often the outer daughter cell divides longitudinally and the
inner transversely (jig. 8). Less frequently, the outer divides trans-
versely and the inner longitudinally (jig. 6). Fig. 7 shows an arrange
ment which is occasionally met with, both daughter cells having
divided longitudinally. Rather frequently one section shows two
cells divided transversely, while the next succeeding section shows
two cells divided longitudinally (figs. 9, 10). This arrangement
could only result from the division of the mother cell at first by 4
longitudinal wall parallel to the plane of the section, and the division
of one of the daughter cells by a transverse wall and of the other by @
longitudinal wall. This case is easy to recognize when the plane °
the section is such that both of the cell boundaries of the second
division are vertical. It is much more difficult to recognize when one
of the cell boundaries of the second division lies in or near the plane
of the section. Such a mode of division is of course frequently
found in pollen mother cells. Fig. 12 shows, however, by far the
most common arrangement of the cells, in which the first wall *
oblique and the walls of the dividing daughter nuclei are approxr
mately at right angles to it. ‘
Most of these various arrangements of the four cells resulting
_ from the division of the embryo sac mother cell have been desct!
by other authors, but in the stages immediately following We ut
ze ~~
1909] MCALLISTER—EMBRYO SAC OF SMILACINA 205
confronted with a series of changes leading to a method of embryo
sac formation quite different from any which has been hitherto
described.
The cell walls which separate the four megaspores break down
and disappear. Immediately following the formation of four fully
separated daughter cells and nuclei (figs. 8, rz) we find a stage in
which the same four nuclei are seen occupying a large cell with no
traces of cell walls separating them (fig. 14). The evidence of the
disappearance of the walls between the megaspores is not based on
scattered examples, selected from a large number of specimens, but
on a large number of continuous series of stages taken from a single
inflorescence.
Fig. 11 shows four cells fully separated by cell walls, while in the
next older flower on the same shoot are found four nuclei in a common
cavity (fig. 14). In fig. 13 the cell walls formed by the second or
homeotypic division have entirely disappeared, while a slight but
distinct cleft, extending across the cell, shows the location of the wall
formed between the nuclei in the first division.
A statistical examination of a number of racemes to determine
the exact stage of development of the mother cell or its products in
each ovule, gave very conclusive evidence of the continuity of these
series. The following is a fair example of an average shoot of the
proper age. In this shoot of nine flowers the youngest flower had
mother cells in a stage later than synapsis. The next older flower
contained mother cells in the prophase and metaphase stages of the
first division. The third showed in one ovule a heterotypic anaphase
stage, and the other ovules showed the heterotypic telophase snide
The fourth flower showed the earlier stages of the second or homeotypic
division. The fifth contained daughter nuclei of the second division
In the telophase stage, and the sixth showed nuclei of this division
Separated by cell walls. The next older flower showed in a part of
ts ovules the four nuclei still separated by cell walls, while the rest
of its ovules showed little or no trace of cell walls between the four
nuclei. The ninth flower, the oldest on the raceme, showed four-
celled embryo sacs in all its ovules, with no traces of cell wall separat-
ing the nuclei. The series here described shows no trace of the
Stowth of one megaspore at the expense of the other three, or of the
206 BOTANICAL GAZETTE: [SEPTEMBER
first and second divisions of such a megaspore to form a four-celled
embryo sac. We must conclude, therefore, that the walls between the
four megaspores break down, and their nuclei become the first four
nuclei of the embryo sac.
In the succeeding stages there is a continuous growth of the nuclei
resulting from the reduction divisions and of the embryo sac formed
from these nuclei. Very soon after the cell walls have disappeared
from between the reduction nuclei, vacuoles begin to appear in the
young embryo sac. Figs. 15, 16, 17 illustrate the gradual enlarge-
ment of the cell containing the four nuclei, and the appearance of
vacuoles in the cytoplasm. The vacuolization more than keeps
pace with the enlargement of the embryo sac, and finally the separate
vacuoles unite to form one large centrally located vacuole. It is at
about this stage of growth that the third division takes place, forming
the eight nuclei of the complete embryo sac (fig. 17). The embryo
sac still continues to enlarge. The nuclei remain unchanged for a
relatively long period. The polar nuclei come together and lie in
contact during this period of quiescence, but are seen to be fused
before the cells in the micropylar region show any signs of differentia-
tion to form the egg apparatus. Not until nearly time for pollination
is there any rearrangement of these cells, which are to form the egg
apparatus.
When finally differentiated ‘the synergids are pear-shaped and
faintly striated. The egg is somewhat larger than the synergids, and
usually has a large vacuole in the basal region. It stains less heavily
than the synergids. I shall not here discuss the formation of the
cell boundaries of the synergids and the egg. The antipodal ney
are smaller than the others, and usually occupy a constricted regio”
at the lower end of the embryo sac. These antipodal nuclei at
stage often number more than three, and in such cases are usually
separated by division walls. :
The most natural interpretation of the phenomena just described
is that the first four cells formed by the division of the embry° -
mother cell are megaspores, and that these four spores jointly com
bine to form one embryo sac. It would seem that this assump?
is the only one possible, for before the division membranes disap 2:
the four cells conform to all the criteria for spores in other similar
1909] MCALLISTER—-EMBRYO SAC OF SMILACINA 207
cases, and the mere loss of the division membranes cannot affect
their morphological value.
Some preliminary studies of Smilacina racemosa seem to show
that the two outer nuclei, formed in the double division of the embryo
sac mother cell, undergo two further divisions to form the eight nuclei
of the mature embryo sac. I shall describe this species, with other
related species, more fully in a later paper.
Recent studies have brought to light an increasing number of
so-called atypical methods of embryo sac formation, which must be
considered in attempting its phylogenetic interpretation.
In Eichhornia, according to SmirH (22), a cell plate is rarely
formed between the two nuclei resulting from the first division of the
embryo sac mother cell, and a cell plate is also rarely formed between
the daughter nuclei of the second division. Reduction takes place
and one of the four megaspores forms the embryo sac.
CAMPBELL (2, 3) reported the discovery of the 16-nucleate embryo
sac of Peperomia pellucida, and in the following year JOHNSON (13);
working independently, published an account of the same species. The
embryo sac mother cell develops directly into the embryo sac. The
sixteen nuclei organize to form an embryo sac with an egg apparatus
Consisting of an egg and one synergid. Six nuclei are cut off singly
around the periphery of the embryo sac, and the remaining eight
nuclei fuse to form the endosperm nucleus. Later JOHNSON (14)
reported that in Peperomia hispidula fourteen out of the sixteen
nuclei of the embryo sac unite to form the endosperm nucleus.
In contrast with the large number of nuclei in the embryo sac
of Peperomia, is the embryo sac of Helosis guayanensts, which es
reported by CHopat and BERNARD (7) to contain only four nuclei
when mature. This 4-nucleate embryo sac is due to the disintegra-
hon of the lower nucleus of the first embryo sac division, so the prod-
ucts of the division of the upper nucleus alone enter into the embryo
Sac structure.
Avena fatua has been shown by CANNON (5) to form its mega-
Spores Similarly to Eichhornia. Commonly no cell walls are formed
Detween the four spore nuclei, but the lower of these nuclei develops
into the embryo sac and the other three degenerate.
A case resembling that of Avena and Eichhornia is reported as
208 BOTANICAL GAZETTE [SEPTEMBER
occurring in Crucianella by Lroyp (15). He reports that in three
species of Crucianella investigated, four megaspores were formed
which were not separated by cell walls, and that “only occasional
exceptions could be found to this.” The upper of these four nuclei
develops into the embryo sac, and the three lower finally degenerate.
Not uncommonly these three lower nuclei undergo division. Many
cases were seen, Lioyp reports, in which the four megaspores had
each divided once, thus forming eight nuclei in a common cavity.
He says: “If these divisions are regarded as the first mitoses of an
embryo sac we have four embryo sacs lying tandem.” Only the
one lying adjacent to the micropyle attains full development. Al-
though he reports the disintegration of the lower megaspores, his
figures admit other interpretations. As late as the third division of
the functional megaspore, what he interprets to be one of the three
lower megaspore nuclei is shown dividing in the same cavity with
the four dividing nuclei of the embryo sac. The dividing nuclei
seem to have the same appearance in every way. This would cer-
tainly show a prolonged activity on the part of these three inner
megaspores. This delayed germination of the lower megaspores and
the similarity of the dividing nuclei in every way, open up many
possibilities. The exact fate of the eight free nuclei formed by the
division of all four of the megaspores is left unsettled. LLoyD com
cludes that the outer megaspore attains full development, and that
the eight nuclei therefore never organize to form an embryo sac jointly.
This is a most interesting case, and a complete history of the embryo
sac from the mother cell may throw light on the interpretation of
multinucleate embryo sacs.
This omission of the division walls between the megaspores of a
tetrad is found by Luovp also in Asperula, which is related to Cru-
cianella. Any one of four spores may germinate to form the a
sac, and the/other three finally degenerate. The three spores wit
do not germinate are at times difficult to distinguish from antipod
nuclei.
An important conclusion to be derived from the behavior : of
Fichhornia, Avena, Crucianella, and Asperula is that the -
walls are not essential to the individualization of a spore, and tha ;
the failure to form division walls between the megaspores does N°
>
SESE EET SD ea eae
el Me a oo ge — eee |
te’ >= or:
pee
;
3 "
3
:
:
1909] MCALLISTER—EMBRYO SAC OF SMILACINA 209
necessarily result in the lily type of embryo sac, even though the nuclei
seem to be of the same size and vitality. So long as the spore retains
its individuality as such, we can expect each spore to develop into a
separate gametophyte, and not till this individuality is lost can we
expect to find more than one spore entering into the structure of a
single gametophyte. This absence of division walls, however, may
very well lead directly to such joint organization of a gametophyte
as we find in Smilacina.
Luoyp, in discussing the nature of the first four nuclei of the
embryo sac of the lily, is in favor of calling them spores. “But
after all,” he says, “spores in the sense meant here are equivalent
to vegetative cells of a somewhat special sort, with no necessarily
separate existence teleologically speaking.” He urges against the
idea that in the lilies the gametophyte begins with the mother cell
this: “It would seem more natural to regard the gametophyte as an
individual by coalescence, having its origin in four like vegetative
cells whose primitive function has been lost.”
In Pandanus Artocarpus and P. odoratissimus, according to
CAMPBELL (4), the mother cell develops directly into the 14-nucleate
embryo sac. The two outer nuclei formed by the reduction divisions
do not divide, while the two inner nuclei divide to form twelve nuclei.
A differentiation of the antipodal cells was reported, but no certain
evidence of nuclear fusions to form the endosperm nucleus was found.
In 1907 Porscu (20) proposed the theory that the two cell groups
in the opposite ends of the angiosperm embryo sac are both to be in-
terpreted as archegonia. The synergids are thought to correspond to
two neck canal cells, and the upper polar nucleus to the ventral
canal cell of the archegonium. According to this theory the embryo
sac of Helosis consists of only one archegonium, the other having been
Suppressed. The behavior of Smilacina stellata perhaps supports
is theory, in so far as it shows the equivalent origin of the two groups
of nuclei which Porscu interprets as archegonia.
Miss Pace. (19) has reported that Cypripedium forms a iota
celled embryo sac by two divisions of the lower of two “megaspores-
This embryo sac may be interpreted by Porscu’s theory to bea single
archegonium. é |
Went (28), in a recent article on the Podostemaceae, reports that
210 BOTANICAL GAZETTE [SEPTEMBER
in Oenone and Mourera a four-celled embryo sac is formed, similar
to that in Helosis. The mother cell following synapsis divides to
form two daughter cells, the upper degenerating. The lower daughter
cell (which he calls the “megaspore’’) divides, and the innermost
nucleus shrinks immediately to a shapeless mass of chromatin that
is visible for a long time. This inner nucleus, though one of the
first four nuclei formed by the division of the embryo sac mother
cell, is interpreted by WENT as a nucleus of the embryo sac and not
a spore. The nucleus remaining from the second division divides
twice to form the four-celled embryo sac. The lower nucleus of this
embryo sac degenerates, leaving only the three nuclei which form the
egg apparatus. WENT notes that his results support the theory of
Porscu, except that the ventral canal cell is on the wrong side of the
cog.
ERNST (10) has expressed the opinion that the 16-nucleate
embryo sac of Gunnera, as described by him, consists of two of the
archegonia of PorscH in the chalazal end of the embryo sac and one
in the micropylar end. Four nuclei in the central region of the
embryo sac fail to form an archegonium, and unite with a polar
nucleus from each archegonium to form the endosperm nucleus.
STEPHENS (23), in a preliminary note on certain Penaeactaé,
reports that the sixteen nuclei of the embryo sac become divided into
four groups, which lie at some distance from one another against the
wall of the embryo sac. Three nuclei out of each group of four
organize what appears to be an egg apparatus, while one nucleus
from each group acts as a polar nucleus, and the four unite to form
the endosperm nucleus. On Porscu’s theory these four groups
would represent four archegonia.
These examples seem to indicate a tendency of the nuclei of the
angiosperm embryo sac to form groups of four. The evidence in
favor of the archegoniate character of these groups, however, seceia
to me to be insufficient as yet. The relationship between the angio”
sperms and the gymnosperms is so remote that a comparison of the
embryo sacs of the two groups with a view to homologizing sts
groups of nuclei associated with the egg is very difficult. ae
CouLTer (8) further defends the idea that the first four nucle 0"
the embryo sac of the lily are megaspores, or “at least their nuclel-
Ig09] MCALLISTER—EMBRYO SAC OF SMILACINA 211
His evidence lies in the fact of their being the product of the two reduc-
tion divisions. Hence they must be “megaspore nuclei, to be recog-
nized as such by their cytological history and structure.” The 16-
nucleate embryo sacs of Peperomia pellucida are considered as result-
ing from two divisions of each of these megaspore nuclei, and the
8- and 16-nucleate embryo sacs, which JOHNSON reports as occurring
in Peperomia hispidula, are regarded as formed by one division of
each of the. four megaspore nuclei to form the 8-nucleate embryo
sac, and by two divisions of each to form the ‘16-nucleate embryo
sac.
CouLTER is inclined to regard it as a fundamental law that the
angiosperm embryo sac is formed from the mother cell by never
more than five nuclear divisions, the reduction divisions and three
divisions of a megaspore. He concludes that the large number of
nuclei in the embryo sacs of Peperomia and Pandanus may originate
by the participation of more than one spore in their organization.
This implies, further, that any embryo sac formed from one spore
which has sixteen or more nuclei can be considered as relatively
primitive, since it would require more than five nuclear divisions to
produce it from the mother cell.
I do not see why the cases of the proliferation of antipodal nuclei
should not be given more weight in the evidence. There is certainly
an abundance of cases among the grasses and in the Ranunculaceae,
as well as in other families, in which the innermost nuclei of the
embryo sac are the product of more than five divisions previous to
fertilization. It seems doubtful whether the embryo sac with more
than eight nuclei can be explained on any such simple hypothesis,
and it is to be remembered that, while there is apparently a physio-
logical necessity back of the double division, there is nothing, ce
STRASBURGER has noted, in the phylogeny of the angiosperms which
would explain or give special significance to a fivefold division.
Brown (1) reports that evanescent cell walls are formed separat-
ing the first four nuclei of the embryo sac of Peperomia Sintensn
and P. arijolia, in both of which the mother cell develops directly
into the embryo sac. Though evidently convinced that in Peperemaes
these first four nuclei are megaspores, BROWN seems to object to the
adoption of this explanation for the lily type of embryo sac in general.
212 j BOTANICAL GAZETTE [SEPTEMBER
Referring to the number of divisions which archesporial cells undergo
to form the mother cell, he says: “Since we can trace the reduction
of these divisions until, among the angiosperms, the archesporial
cell may, without dividing, form one megaspore mother cell, it does
not seem reasonable to suppose that the divisions of the mother cell
to form four megaspores may not also be left out, and the mother
cell function directly as a megaspore.” Any analogy, however,
based upon the archesporial cell, has against it that this latter cell is
a doubtful morphological unit.
It cannot be maintained that any morphological interpretation yet
proposed satisfactorily explains all the diverse types of embryo sac
formation which have been described. That there are so many
variations in important particulars gives ground for the expectation
that further study may fill up many gaps in our current interpretations.
It is plain that within the group of the Convallariaceae there ”
types which go far toward explaining the origin of the old and familiar
lily type of embryo sac. It is certainly plain that in Smilacina
stellata four megaspores are formed, which are unmistakably separated
by cell walls and subsequently recombine to form the first four nuclei
of the embryo sac.
All the evidence favors the view that the first four nuclei of the
lily embryo sac are morphologically, as well as from the standpoint
of the reduction divisions, to be interpreted as megaspore nuclei.
SUMMARY
1. The mother cell of Smilacina stellata divides twice to form fout
nuclei, which are separated by walls to form four megaspores.
2. The division walls and plasma membranes which separate me
four nuclei are absorbed, so that the four reduction nuclei ocCUPY
a common cell cavity. :
3- Each of these four nuclei divides again, and the resulting eight
nuclei organize to form the embryo sac.
4. It is plain from these facts that we have four individual meg*
spore cells*combining to form one embryo sac or gametophyte ™
Smilacina stellata. 6
5. It is thus strongly suggested that in the embryo sac of the hie
the first four nuclei are morphologically megaspores.
Ree? Sey ea eee Ree era ee hh eS,
1909] MCALLISTER—EMBRYO SAC OF SMILACINA 213
6. In Smilacina racemosa the outer daughter cell of the hetero-
typic division develops into the embryo sac, although the long per-
sistence of the two nuclei formed by the division of the inner hetero-
typic nucleus might suggest that they should be considered a part of
the embryo sac. Smilacina racemosa shows temporary cell division
at the close of the homeotypic division, agreeing in this respect with
Smilacina stellata.
I wish to express my obligations to Professor H. D. DENSMoRE, in
whose laboratory at Beloit College this investigation has been largely
carried on. I am also indebted to Professor R. A. HarPEr for his sug-
gestions and criticisms during the preparation of the manuscript.
LITERATURE CITED
I. Brown, W. H., The nature of the embryo sac of Peperomia. Bot. GAZETTE
46: 445-460. pls. 31-33. 1908.
2. Campsett, D. H., A peculiar embryo sac in Peperomia pellucida. Annals of
Botany 13:626. 1899.
3: ———, Die Entwicklung des Embryosackes von Peperomia pellucida Knuth.
Ber. Deutsch. Bot. Gesells. 1'7: 452-456. pl. 31. 1899.
‘ —— The embryo sac of Pandanus. Annals of Botany 22:330. 1908.
» Cannon, W. A., A morphological study of the flower and embryo of the wild
Oat, Avena fatua. Proc. Calif. Acad. Sci. III. 1:329-364. pls. 49-53. 1900.
6. CHAMBERLAIN, C. J., Winter characteristics of certain sporangia. Bor.
GAZETTE 25:124-128. pl. rr. 1898.
Cxopar, R., eT BERNARD, C., Sur le sac embryonnaire de l’Helosis guaya-
nensis,
ap
oA PEENE ol
Oo
ty
g
Re]
>
Q
of
°o
8
g
3
3
o
Qu
E
= (
8
5
Z
am
FE
&
ty
5
a
g
g
S
a
Befruchtung bei Paris quadrifolia und Trillium grandiflorum. Flora 91:1-
46. pls. 1-6. 1902.
= aa, Zur Phylogenie des Embryosackes der Angiospermen. Ber. Deutsch
ot. Gesells. 26a: 419-437. pl. 7. 1908.
™ Guicnazn, L., Stracture et division du noyau cellulaire. Ann. Sci. Nat.
~~» Nouvelles études sur la fécondation. Ann. Sci. Nat. Bot. VII. 14:
163-296. pls. 9-18. 1891. : A
» Jonson, D. S., On the endosperm and embryo of Peperomia pellucida.
OT. GazETTE 30: 1-11. pl. 1. 1900.
214 BOTANICAL GAZETTE [SEPTEMBER
14. JoHNson, D. S., A new type of embryo sac in Peperomia. Johns Hopkins
Univ. Circ. 195: 19-21. pls. 5, 6. 1907.
15. Luoyp, F. E., The comparative embryology of the Rubiaceae. Mem. Torr.
Bot. Club 8:1-112. pls. 8-15. 1902.
16. Overton, E., Beitrag zur Kenntniss der ooucctn: und Vereinigung der
Geschlechiaproducts bei Lilium Martagon. Zurich. 1891.
, Ueber die Reduktion der Chromosomen in den Kernen der Pflanzen.
Vierteljahresch: Naturf. Gesells. Zurich 38: 169-186. 1893.
, On the reduction of the chromosomes in the nuclei of plants.
Annals of Botany '7:139-143. 1893.
19. Pace, Luta, Fertilization in Cypripedium. Bor. GAZETTE 44:353-374
pls. 24-27. 1908.
20. PorscH, O., Versuch einer phylogenetischen Erklirung des Embryosackes
und der Sor eslien ee der Angiospermen. 1907-
21. ScHNIEWIND-TuIES, J., Die Reduktion der Chromosomenzahl und die ihr
folgenden Ketathehaiigen i in den Embryosackmutterzellen der Angiospermen.
Jena. 1901.
22. SuirH, R. W., A contribution to the life history of the Pontederiaceae. BOT
GAZETTE 25: 324-337. pls. 19, 20. 1898.
23. SrepHEns, E. L., A preliminary note on the embryo sac of certain Penaeaceae-
Annals of Romany 22:329. 1908.
24. STRASBURGER, E., Neue Untersuchungen iiber den Befruchtungsvorgang © bei
den Phavistoeames. Jena. 1884.
, Ueber Kern- und Zelltheilung im Pflanzenreich. Hist. Beitr. T. Jena.
1888
, The periodic reduction of the number of chromosomes in the life
heise of living organisms. Annals of Botany 8:281-316. 1894- :
=e brat: Ms es igus. J. F. A., Notice sur le développement du s4
Archives Neerlandaises 15:45?”
4 o =
456. pls. 2. 1880. + th
. Went, F. A. F. C., The development of the ovule, embryo sac, and egg in the
; Podostemaceae. Recueil Trav. Bot. Néerl. 5:1-16. pl. I. I ‘
29. WiEGAND, K. M., The development of the embryo sac in some » monocot
ledonous plants. ‘Ber: GAZETTE 30:25-47. pls. 6, 7. 1900.
EXPLANATION OF PLATE XV
All figures were drawn with the aid of a camera lucida. The magnification
in all the drawings is 670 diameters. The micropylar end is upward _
drawing.
Fic. 1.—Mother cell in synapsis stage; without tapetal cell.
Fic. 2.—Mother cell in prophase stage of first division; two cell layers
the epidermis and the mother cell. : ple
Fic. 3.—Early metaphase stage of the mother cell, showing thick dow
chromosomes characteristic of first reduction division
“pea
oO
betwee
PLATE XV
McALLISTER on SMILACINA
BOTANICAL GAZETTE, XLVIII
Igog] MCALLISTER—EMBRYO SAC OF SMILACINA 215
Fic. 4.—Formation of cell plate and daughter nuclei at the close of first
_ division of mother ce
2
.
;
i cal et FS
Fic. 5.—Early metaphase stage of homotypic division; axes of spindles
oblique.
Fic. 6.—Daughter nuclei and cell plates f
outer daughter cell dividing transversely and inner one longitudinally.
Fic. 7.—Nuclei of second division fully formed, arranged bilaterally; division
membranes of second division do not reach outside walls.
Fic. 8.—The outer daughter cell has divided longitudinally and the inner
one transversely.
FIGs. 9, 10.—Two successive sections of the same nucellus, showing the division
of an approximately spherical mother cell; hete rotypic division longitudinal;
one daughter cell in the homeotypic division dividing longitudinally and the other
transversely.
Fic. 11.—Row of four very large megaspores, with the division =e very inde-
ite.
Fic. 12.—Commonest arrangement of megaspores, in which first division is
oblique and second at right angles to first; walls have disappeared but plasma
membranes still persist. ae
IG. 13.—Four megaspores; a cleft between two middle nuclei is all that
remains of division membranes of cells. é
Fic. 14.—Four megaspores, with no traces of cell walls, forming four-celled
Stage of embryo sac.
Fics. 15, 16.—Stages in the vacuolation of the four-celled embryo sac.
Fic. 17.—Eight-celled embryo sac, showing micropylar and antipodal groups
of nuclei, the two polar nuclei already separated out.
] £ d divician:
’
A STUDY OF PINON PINE
P.n}6 PHLIELIPS
GENERAL DISTRIBUTION
No other tree species of the southern portion of the Rocky Moun-
tain region presents more difficult problems in maintaining and repro-
ducing the natural stands than does the pifion pine (Pinus edulis).
It ranges from northern Mexico to eastern Utah, and Colorado Springs,
Colorado. In an east-and-west direction it extends from the hills
of western Texas to California. Along the northern and eastern
borders of its range it is shrublike and of botanical importance only.
In southern Colorado, Arizona, and New Mexico, it has a great eco-
nomic and silvicultural importance, which will steadily decrease unless
measures are taken to prevent excessive utilization.
It is commonly found in mixture with the one-seeded juniper
(Juniperus monosperma) in the northern part of its range and with the
alligator juniper (Juniperus pachyphloea) and one-seeded juniper in
the south. Throughout its distribution it is associated with weste™™
yellow pine (Pinus ponderosa) and the scrub oaks (Quercus Gambelit
and Quercus acuminata), often forming with these species a transition
belt between stands of juniper and western yellow pine. Occasionally
it is found with stunted Douglas fir (Pseudotsuga taxifolia). In
association with the junipers, it forms the distinct woodland type
so characteristic of New Mexico and Arizona, which in this reg!
covers a more extensive area than any other forest type, and 63
which the pifion is decidedly the most important tree. It is occasion-
ally seen in pure stands over small areas, but this is rare.
LOCAL OCCURRENCE
The tree thrives best at a general elevation of 1650 to 2350" (540°
to 7700 feet) on moderate to steep mountain slopes and over road,
level, or sloping mesas. Small isolated specimens were found UP
to an elevation of 2600 and 2750™ (8500 and gooo feet), while occ
Botanical Gazette, vol. 48] [2x6
pie ME a Milk ee
Eos, Game
- 1909] PHILLIPS--A STUDY OF PINON PINE 217
sional specimens may be found even higher than this. The best
stands are found on coarse gravel, gravelly loam, or a coarse sand,
of 1.5™ (5 feet) or more in depth, on which humus and ground cover
are almost entirely lacking. The species often occurs on rocky
areas, where the soil is only 15 to 30°™ (6-12) in depth, and fre-
quently it is found growing in rock crevices. It is one of the first
trees to gain a foothold on the lava overflows which are known
throughout the southwest as mal pais. This rock in its disintegrated
form supports fair tree growth, but even before disintegration has
progressed very far, the junipers and pifion may be found encroaching
upon it.
Another encroachment form of the pifion is to be found on small
mounds which rise 0.6 to 3™ (2 to 10 feet) above the general level
of the desert-like tableland at approximately 1500™ (5000 feet)
elevation. On such islands as these, the pifion and one-seeded
juniper take possession and maintain a limited growth. The same
feature is noted at the bases of the hill and mountain slopes which
bound these tablelands. This remarkably distinct tension line seems
to be due to a greater soil porosity, less grass growth, and a smaller
alkali content, which are manifest in slightly higher elevations. The
distribution of these trees on such small mounds and limited in such
a distinctive manner presents an ecological problem for future investi-
gation.
On slopes where site conditions are favorable for western yellow
pine, the pifion usually occupies the south and west aspects. Where
Conditions become less favorable, it occupies the north and east slopes,
while the south and west slopes are bare or nearly so. This ability
to stand poor conditions is also shown on a large number of mountain
Slopes ranging from 2830 to 3135™ (6000 to 7000 feet) in elevation,
where scattering Douglas fir, of scrubby growth and badly affected
With witch’s broom, is found in the cafions; western yellow pine on
the middle slopes; and pifion on the ridges and upper slopes, where
the soil is scant and the soil moisture low.
A distinctive peculiarity was observed between Servilleta and Taos,
New Mexico, in an open stand of the species in which approximately
two-thirds of the trees have constricted bases at the surface of the
stound. This constriction amounted to an average of 197" (0.75")
218 BOTANICAL GAZETTE [SEPTEMBER
in radius, but was occasionally noted where it amounted to 38™™
(r.5™). Such a constriction is often seen on individual trees in
nearly any stand, but in no other case was it found to be a stand as
characteristic as it was near Servilleta.
Pifion is also resistant to severe climatic conditions, since it will
succeed over severely exposed slopes where the average annual
precipitation is less than 33°™ (13%) and where evaporation and
transpiration are high because of the semi-arid climate, the large
amount of sunshine, and the prevalence of winds. In this respect
it is undoubtedly the most resistant pine in the southwest. However,
it prefers a slightly greater precipitation and areas less exposed to the
wind. An example of the unfavorable influence of strong winds and
a Close-textured soil was noted in the vicinity of Fort Stanton, New
Mexico, where a level plateau of nearly 8" (5 miles) in length did
not support a single tree, while similar plateaus on all sides, with less
wind sweep and a coarser soil, showed luxuriant growth of both the
pifion and the juniper. The tree does not live as long as the junipers,
and in general is less resistant to unfavorable climatic conditions.
In the drought which occurred in New Mexico from 188g to 1904;
pifion suffered considerably more than the junipers. Many mixed
stands were observed in New Mexico and southern Colorado in
which 75 to 95 per cent. of all dead trees were pifion. In the frost
which occurred in April, 1907, pifion was affected, while the junipers
resisted practically all injury. In the wet freezing snow of October,
1906, which caused immense damage to the forests of the southwest,
fewer branches were broken from the pifion than from the brittle
junipers.
The tree is also more resistant to disease than most of the conifers
with which it associates. It is much less affected by the so-called
false mistletoe (Razoumofskya) than is the western yellow pine and
the junipers. It has fewer insect enemies than the western yellow
pine, and is not affected by the witch’s broom as is often the case
with Douglas fir in the southwest.
TOLERANCE AND FORM
Pifon is distinctly an intolerant tree. During its seedling —
it prefers a moderate shade, and hence reproduces best under thé
1909] _ PHILLIPS—A STUDY OF PINON PINE 219
shade of older trees. After the seedling stage is passed it prefers the
open, and is one of the most intolerant of forest trees. This gives an
orchard-like appearance to most stands of this species. Occasionally
stands of 0.7 density were noted, although few stands have more
than 0.6 density.
On the best sites the trees reach a maximum height of 12 to 13.7™
(40 to 45 feet) and a diameter of 60 to 75°™ (2 to 2.5 feet) at breast
height, but ordinarily the mature individuals range from 3 to 10.5™
(10 to 35 feet) in height and from 15 to 45°™ (0.5 to 1.5 feet) in diam-
eter. A difference in development was apparent on different sites. On
exposed sites the tree is globular, very scraggly when mature, and
has little or no clear length. On favorable sites trees in the open
have a very short clear length and a fairly regular globular or egg-
shaped crown. If grown in stands, the trees have a greater clear
length and a flat or vase-shaped crown. Young trees on favorable
sites are conical or globular in shape and usually very regular in
form.
On the most exposed sites, shrublike trees were found which
were fifty to eighty years old, and only 1.8 to 3™ (6 to 10 feet) in
height, with a crown diameter reaching a maximum of two to four
times the height of the tree. On such trees it was impossible to dis-
tinguish the leader from the branches, and the general appearance
of the tree was much like that of the dwarf mountain pine (Pinus
monticola). The foliage is more densely clustered on these dwarf
trees than it is on trees in the open, with shorter and apparently
thicker leaves. Practically all trees, whether growing on poor or
800d sites, are characterized by dead and half-dead branches, which
are retained on the tree for several years. This is characteristic of
nearly all species in the southwest and is due to the small amount of
Stowth that is made, the necessity of retaining only a small amount
of living tissue, and the dry nature of the climate, which allows the
retention of dead branches for a longer period than would a moist
Climate. In exceptional stands, such as occur to the west of Servil-
leta, New Mexico, where a clear length of 4.5 to7.6™ (15 to 25 feet)
'S not exceptional, the branches are shed largely because the density
of stand prevents the formation of as large branches as are found in
those trees which enjoy full sunlight.
220 BOTANICAL GAZETTE [SEPTEMBER
WwooD
Pifion wood is moderately heavy for the pines. It is used exten-
sively for fuel and has been limitedly used for fence posts, telephone
poles, corral posts, mine lagging, railroad ties, charcoal, and inferior
lumber. Some authorities have recommended its use for fence posts,
but this is to be seriously questioned as it has little durability in contact
with the soil, and even the natives are discarding it for such use. It
may be rendered valuable, however, by the use of preservatives. The
tree is remarkable in its fuel value, and its use for such a purpose
should be greatly encouraged. It is a common practice to cut
branches or trees after they have been dead about two years. If
cut before this time, the wood has not seasoned sufficiently to burn
readily. If cut after this time, it has usually deteriorated to some
extent. As a hearth fuel, it is not surpassed by another conifer and
by only few hardwoods. It starts to burn readily, retains fire for a con-
siderable length of time, gives a large amount of heat, and does not
throw sparks. Since open fires are very common in this region, this
wood serves an excellent purpose. Sample acres which have been
clear cut have given a yield of 180 to 360%™ per hectare (20 to 4°
cords per acre), while extensive stands have averaged go to 108% ™
(10 to 12 cords).
FRUIT
The young cones are dark red and occur in elongated clusters.
The pistillate form is easily distinguished by short stalks. Both
sorts are very plentiful in seed years, but are scarce during other
years. The mature cone is short, top-shaped, 19 to 50"™ (0.75
2") long and often as broad as long. The cones open on the tree
and are covered by a large amount of free resin, which makes aes
difficult to handle. They often occur on trees only 0.9 to 3°
(3 to 4 feet) in height, which are ten to twenty years old, but the best
crops are borne on mature trees which produce 35 to 280 (1
bushels) of cones; each cone contains two to thirty seeds, with _
average of ten to twenty seeds. The trees have been known to yiel
336 of seed per hectare (300 pounds per acre), while a much large
area has been known to produce an average of 7 3k# per hectare (65
pounds per acre).
hg) ee eee i eee
si, ie Erle 1
1909] PHILLIPS—A STUDY OF PINON PINE _ 221
Seed years usually occur at five-year intervals, but have been
reported at shorter intervals than this. The seed is well rounded at
the base, tapering with prominent ridges to an acute point. It is
usually dark brown on the lower side, with more or less mottled
orange yellow on the upper side, 9 to 12.5™™ (0.375 to 0.5") long,
6.5 tog™™ (0.25 to 0.375!) broad, with a thin shell which cracks
most easily along the line of the most prominent ridge. The seed
wings are about one-half the length of the seed, easily detached, and
of no practical use in seed distribution. The seeds usually have a
high percentage of infertility, which varies from 5 to 20 per cent.,
but in one case went as high as 85 per cent. Poor seeds are often
lighter in color than good seeds. Germination power is lost very
readily, which necessitates special storing when they are to be used
for artificial planting, and good site-conditions when the stands are
to be reproduced naturally. It is a matter of note that the seeds from
the northern portion of the range are usually considered better than
those from the south. Five —— collected in various localities
gave the following results:
pound, | Poy | Peseause | Pereatege | Perce | where cllecd
(453.68™) | knife test | water test | greenhouse in open
3510 N. M.
oheied 87.2 84.0 82.2 5.6 Ft. Bayard,
2215 89 I 86.6 80.3 is 2 Tres Piedras, N. M
one QI.2 86.0 78.1 70.4 | Ft. Garland, Col.
1950 92.7 88.5 81.3 71.0 | Ft. Garland, Col
ss 99.2 97-1 96.4 90.3 Lincoln, N
Weevils sometimes affect the seed before the cones open. Birds
and rodents eat the seed extensively, and stores are made ses moun-
tain rats which were found to contain a maximum of 35 to 70! (I to 2
bushels) of clean seed. Ants are known to eat seed, especially at
lower levels. In the early days, the Indians and Mexicans used the
Pifion as a staple article of food. At present, it is gathered in immense
quantities and sold as a delicacy. It is eaten most extensively in and
about the region where the tree grows naturally, but large amounts
are being sold at fruit stands throughout most of the United States.
To prevent the seeds from spoiling and to retain flavor, they are
"sually baked immediately after being gathered.
222 BOTANICAL GAZETTE [SEPTEMBER
Most of the seeds are collected by Mexican women and children,
who usually spread a sheet or blanket on the ground and then shake
or pound the tree and its branches until the seeds fall from the open
cone. Later in the season, the seeds are picked up by hand from the
ground beneath the trees. In the best part of the seed harvest,
enough are gathered by single families to be sold by the grain bag
full or the wagon load. Since the Mexicans take almost no precau-
tions against the spreading of smallpox, it is said that the worst
ravages of the disease occur during a seed year of the pifion. Single
dealers have- been reported as having bought gooo to 21,5008 (20,000
to 50,000 pounds). The delicate flavor of the seed makes it a favorite,
and an extensive market is being rapidly developed for it. During
seed years the native collectors sell it at the rate of five to fifteen cents
per pound, according to the ease of collecting the seed and the prox-
imity of the market, while dealers in many of our cities sell the seed
at a rate of forty to sixty cents per pound.
REPRODUCTION
Natural reproduction is limited because of the infrequency of seed
years, unfavorable climatic conditions, infertility of seed, rapidity
with which the seed loses its germination power, loss of seed eaten
by rodents, birds, and man, and unfavorable site-conditions. Grazing
interests are also a factor in limiting the reproduction of the species
since sheep, cattle, and goats are grazed throughout its entire distri-
bution. It is apparent to even the casual observer that extremely large
areas are not reproducing themselves, yet owing to the difficulties of
site and the methods by which the tree may be reproduced, the prob-
lem of reproduction is an extremely difficult one, and one for which,
at the present time, no adequate solution can be offered.
FUTURE MANAGEMENT
From the nature of the stand in the southwest, it is apparent that
clear cutting would not be ari advisable system, because of the exposure
of the site and the difficulties of restoring the stand. On the other
hand, the large amount of seed consumed by man and other agencies
makes natural seeding exceedingly difficult, and even though gt?!
and fire are entirely eliminated, it is doubtful if satisfactory reproduc:
ryo9] PHILLIPS—A STUDY OF PINON PINE 223
tion will be secured in even a bare majority of sites. Until the prob-
lem of reproduction is more thoroughly worked out, the policy should
be to remove only the dead and dying pifion trees for fuel, thus allow-
ing a careful management without encroaching seriously upon the
natural stands as is being done at the present time. It would seem
from the nature of the site that the stand could be made to succeed
best by the selection system, consisting of the removal of the dying
trees. The sale of this fuel with that of a large portion of the seed
should furnish a moderate income. This production would be low,
as contrasted with high-type coniferous forests in other regions, but
when consideration is given to the value of this species for fuel and
seed, the question of immediate returns is a minor one.
UNIVERSITY OF NEBRASKA
BRIEFER ARTICLES
ON THE DEMONSTRATION OF THE FORMATION OF
STARCH IN LEAVES
For a qualitative demonstration of photosynthesis in starch-forming ©
leaves it is advantageous to know the time in darkness required for the
disappearance of accumulated starch, and the time in light required for its
subsequent demonstrable formation. No general rule can be given for
either, since the time required varies widely for the different species.
Therefore, in continuation of the series of studies carried on in the labora-
tory of plant physiology of Smith College on the physiological constants
of the educationally useful plants,t I have tried to determine these data for
such plants, and also, by comparison, the best plants for the purpost-
Throughout this paper I have used the expression “disappearance of
starch” rather than ‘“‘translocation.” In a general way the processes, of
course, correspond, yet the term “translocation” implies the removal 0:
the starch from the leaf, while here we are dealing only with its disappe*™
ance as starch. :
The method employed in the present study was as follows: Five actively
growing plants of each species, always after a bright day and between 4 2
5 o’clock, were put in a dark room having a steady temperature of 18°-22° C.
as recorded by a thermograph. Twice a day, about 9 A. M. and 2 P. M.,
leaves were tested for starch by SAcHs’s iodine method, and the time when
all starch had disappeared was noted. No attempt was made to find the
exact hour when the leaves were empty. This would necessitate testing
them every hour during the night as well as during the day,
purpose of the present study, the results would be of little value-
following table, therefore, the time in darkness required to empty the
of starch is given in night and day periods rather than in hours.
iodin test the leaves were first boiled 1 minute to swell the starch,
blanched in warm alcohol, were put in water a few minutes to remove of
alcohol and soften the tissues, and were then immersed in 4 solution 0
iodin. The solution used was git potassium iodid, 1°™ iodin, 10% watel,
to which, when dissolved, water was added to make 1 liter of solution. fie
Thus was the time of disappearance of starch determined with su
cient accuracy for all practical purposes. To determine the time Ted"
‘Bor. GAazETTE 40:302. 1905; 45350. 1908; 482254. 1908; 465° 1968
46:221. 1908.
Botanical Gazette, vol. 48]
leaves
or the
were
the
[224
PO Le eT
1909] BRIEFER ARTICLES 225
for starch formation, it was found best to use some type of screen such that
a sharp contrast would show between the light and dark parts; and for this
purpose light-screen boxes were used. .These boxes have been fully
described by Professor GANONG in the Botanical GAZzETTE.? Briefly,
they are small boxes made of white paper blackened inside, with a network
of threads across the top to support the leaf, and holes near the bottom
to allow the air to pass through freely. A glass plate covered with tinfoil
having a pattern cut in it is held closely against the network by a wire
spring. When in use the leaf is held between the glass plate and the net-
work. The principal advantage of these screens is that while excluding
all light, they allow nearly the normal access of carbon dioxid to the leaf.
The caution, by the way, against using screens which cut off all carbon
dioxid as well as the light has been made several times in recent years, but
some of the new elementary textbooks are still copying the old and erroneous
method of putting cork or tinfoil on both sides of the leaf. Several light-
screen boxes were attached to the leaves which had previously been emptied
of starch, and the plants were placed in strong diffuse light. Leaves were
then taken off and tested for starch at 10-minute intervals. In order to
compensate the effects of individual peculiarities, 5 plants of each species
were tested. The results given in the table are for full-grown (except in
: € three cases noted), but not mature, leaves on actively growing plants,
M pots, in a greenhouse. In the first column is given the time in darkness
Tequired to empty the leaves of starch; in the second, the time in diffuse
light required to. make enough starch to show a pale but clearly defined
figure with the iodin test; in the third, the time required to show a sharply
defined, dark figure; while in the fourth is given the time required for the
lodin to produce its full effect.
The best leaves, obviously, for this study are those in which photosynthe-
Sis is most active, from which starch disappears most rapidly in darkness,
from which the chlorophyll can be extracted quickly leaving the leaf white,
and which give the iodin reaction quickly. As shown by the accompanying
table, these are Pelargonium hortorum zonale, Fuchsia speciosa, Senecio
mikanioides, Impatiens Sultani, and young plants of Helianthus annuus,
Ricinus communis, Phaseolus vulgaris, Zea Mais, and Cucurbita Pepo.
On the other hand, some leaves are not good for this study. Begonia
palmata, Oxalis Bowiei, and Pelargonium peltatum, when boiled to swell
the Starch, partially disintegrate, so that the figure does not show clearly
with the iodin test. It is possible, of course, to apply the iodin test without
Previous boiling of the leaf, but it takes 24 to 48 hours according to the
* Bor. Gazerre 432277. 1907.
226 BOTANICAL GAZETTE [SEPTEMBER
age of the leaf; besides, these leaves turn brownish yellow on the applica-
tion of iodin and therefore do not show clearly the reaction with starch.
Ficus elastica requires more than one day to make a perceptible amount.
Only very young leaves of Primula obconica, Primula sinensis, and Cinera-
ria cruenta can be emptied of starch; being stemless plants, they probably
use the older leaves for its storage. Young plants of Pelargonium domesti-
Disavprap- segs ea Sad fee
NAME OF PLANT Retintag lt (T. 20°-25°C.) IopIN TEST
: DARKNESS
(T. 18°-22° C.) Perceptible fig. Good fig. |
nights and days minutes minutes minutes
PINNUOasiiat oe er oo ce 2 I 30 120 es
Begonia coccinea........... 3 3 60 240
B ca oleracea...) ... 2s. ° 20 5 5
Cineraria cruenta (young Is)| 5 4 45 180 3°
Coleus Blumei............. I 30 5° 36
Cucurbita Pepo............ I ° 15 5° as
Euphorbia pulcherrima 2 I 60 240
Fuchsia speciosa........... I ° 45 9 15°95
Helianthus annuus......... I ° 30 120
Heliotropium peruvianum I ° 45 120 s Bie
Impatiens Sultani.......... I ° 30 120
Lupinus albus............. I ° 60 240
alis Bowiei............. I ° 45 240 petits
Pelargonium domesticum...| 2 I 5° 240 4
Pelargonium peltatum...... = 2 50 270 =
Pelargoni rto x :
OMS 2 I 20 5° ~_
Phaseolus vulgaris......... I ° 20 oe 5 °
Primula obconica (young Is). 5 4 120 240 s*
Primula sinensis (young ls) . 4 fe 45 120
Raphan se ea fe) 35 6 3
Ricinus communis... .... I ° 20 60 oss
Salvia involucrata.......... 2 I go I20 ait
Salvia splendens........... 3 2 30 60 =e
Senecio mikanioides....... . I ° 20 5° 5
Senecio Petasitis........... 3 2 30 180 25
Tropaeol 1 Rear tis 2 I 50 ge ;
Wels Pathe cates: I ° 60 240 =
Cl TMI ss 3 2 30 120 5
cum empty their leaves of starch in about 40 hours, but older p _ -
unsatisfactory, because, even after 4 days in darkness, there are ant d
of starch in the mesophyll. All these plants, except Oxalis Bowtet, er
the young plants of Pelargonium domesticum, require 3 to 5 days in darkm
—too long a time for the subsequent good of the plant. First
Prolonged darkness produces two distinct deleterious results. :
some plants, as Heliotropium and Impatiens, after 3 or 4 days in ose
drop their leaves, owing to some derangement of their mechanis™,
Ig09] BRIEFER ARTICLES 227
cause of which I have not investigated. Also, Tropaeolum leaves soon
turn yellow in darkness. The second injurious result, and the most impor-
tant in this study, occurs in nearly all plants. Some of the photosynthate
is of course being constantly used in growth or for storage in the stem, and
since the plant can make no more in darkness, the percentage of sugar in
the cell-sap decreases more and more by diffusion into the stem. Then,
as PFEFFER has shown,3 when the plant is brought into the light no starch
is deposited until this percentage of sugar is repaired. The following
example is typical: Two plants of Fuchsia speciosa, apparently alike, were
put in the light at the same time, after having been in darkness, the one
64 hours, the other 16 hours. Halves of leaves tested showed no starch.
After 2 hours in the light, the other halves on the first plant showed much
less starch than those on the second plant. To obtain the most rapid
formation of starch, therefore, it is important that the plant should be kept
in darkness only long enough just to cause the disappearance of starch.
The disappearance of starch is not always even. In Coleus, Primula
verticillata, Primula obconica, and Fuchsia speciosa, the base of the leaf is
emptied of starch before the tip. This agrees with what SacHs found in
Some other leaves.4 So far as I have tested them, I have found this to be
true only of ovate or oblong leaves. This may be correlated with the greater
abundance of stomata near the base of the leaf. _In round leaves like Pelar-
gonium zonale and Tropaeolum, the starch seems to disappear evenly from
all parts. The starch disappears from the young leaves on a plant before
It does from those which are mature.
The effects of temperature on the amount of starch present are especially
important. In several of my experiments, leaves of Fuchsia spectosa,
Euphorbia pulcherrima, and Pelargonium zonale which were kept in direct
sunlight 4 hours showed very little starch, while leaves on plants in diffuse
light, at the end of 4 hours were full of starch. Fuchsia speciosa after being
in diffuse light at 28°-31° C. for 3 hours showed only a trace of starch, while
other leaves in 3 hours at 18°-20° C. appeared black with starch, with the
lodin test. A comparison of these two sets of experiments shows that the
small amount of starch present in leaves in direct sunlight isund btedly con
hected with their high temperature. In order to get the best results, there-
fore, from experiments in the formation of starch in the leaves of potted
steenhouse plants, it is necessary to keep the plants at a temperature not
exceeding 22° C., and to insure this it is well to keep them in diffuse rather
than in direct sunlight. It will be of interest to compare these results with
those obtained by Sacus for outdoor plants, as described in his classical
3 Physiology 1: 321. 4 Ges. Abhandl. 360.
228 BOTANICAL GAZETTE [SEPTEMBER
paper.5- He found that the rate of the disappearance of starch from the
leaves increases with the temperature. When the nights were very warm,
some plants (Nicotiana, Phaseolus, Juglans, and others) completely emptied
their leaves of starch in one night. But after cool nights, 6°-9° C., there
was no perceptible loss of starch in some, and the disappearance was incom-
plete in others. SaAcus found also that the amount of starch present at any
time of the day is affected by temperature. At a temperature of 20°-25° C.
the quantity of starch in the leaves increased steadily from morning until
evening. But on hot afternoons at a temperature of 30°-35° C. the leaves
of Helianthus contained less starch than in the morning at 8 o’clock. The
reason for this phenomenon is found in the fact that translocation from the
leaf into the stem increases with rising temperature more rapidly than
photosynthesis. All of these considerations emphasize the important pre-
caution that to obtain the best starch formation in leaves, the temperature
should not be permitted to rise above 20°-22° C., which is apparently the
optimum for this process, as it is for the best general health of such plants
as are used in these studies.
Also it must be remembered that plants cannot give good results in this
or any physiological experiment, when suffering from previous starvation,
as in the case of pot-bound plants or those which have been kept in darkness
for a long time; when suffering from over-stimulation from high feeding,
or from being kept at too high temperatures; and when they have passed
their grand period of growth. Asa rule plants, and particularly annuals,
are in their best condition just before flowering —SoPHIA EcKERSON,
Smith College.
THE MORPHOLOGY OF RUPPIA MARITIMA—A CRITICISM ¢
In section D, “Function of the root,” Graves (p. 113) has wandered be-
yond the natural limits of his paper as a morphological study, and while the
propriety of this is perhaps questionable, the basis for this criticism is that
this section D contains a statement which I think is an unwarranted mis-
interpretation of some of my own writings, and alse . statement that would
leave most readers misinformed. I wish first to consider the following:
“On the other hand, Ponp’s experiments? fail to show conclusively whether
or not water and dissolved salts are absorbed by the part of the plant above
5 Arbeit. Bot. Inst. Wiirzburg 3:1 ff., as cited in Ges. Abhandl. 354-387-
® Graves, A. B., The ane ga) of Ruppia maritima. Trans. Conn- Acad
Arts & Sciences 14:59-170.
‘7 Ponp, Raymonp H., 3 biological relation of aquatic plants to the substratum
U. s. Fish Commission Repod 1903:483-526. 1905.
1909] BRIEFER ARTICLES 229
the soil.” Being somewhat uncertain as to the intended meaning of this
statement, I have learned by correspondence that Graves believes that in
my paper I have committed myself to the notion (in the absence of con-
clusive evidence) that the larger submerged and rooting water plants
derive their mineral food exclusively from the soil, and that there is no
absorption of mineral food by organs other than the roots. Such a notion
I have never held and do not consider my paper as warranting or encoura-
ging such an interpretation. My efforts to force certain species to live and
grow in nutrient solutions and without a substratum were not continued
to a satisfactory conclusion, and for that reason I remained noncommittal
on the possibility of absorption by the other organs of the plant.
My general conclusion was that certain species which were tried were
found to be dependent upon their rooting in the soil for optimum growth
and cannot survive a single season if denied a substratum of soil.
Whatever the absorption by the organs other than the roots amounts to
(in the species tried), it is so small that the species would probably become
extinct if forced to depend upon it exclusively under otherwise natural
conditions.
Looking at section D as a whole we find that every paragraph is general
in its scope and treatment. GRAVES tes four reasons for not placing
too much emphasis “on the absorbing capacity of the root.”” One of the
reasons is “‘the total lack of branches and slenderness of the roots.” I
think any reader would infer that submerged plants have slender roots
without branches. So far as I know the statement is correct so far as the
“slenderness” is concerned but’in my paper (/. c.) there is a section on
factors influencing the development of lateral roots
Speculation as to the relative importance of absorption by the roots
of submerged plants as compared with that in the case of land plants is of
little value. I refer particularly to the statement by GRAvEs as follows:
‘In brief, the absorption carried on by the roots of submerged plants and
the importance of this function in the economy of the plant is much greater
than is implied by ScHENCK—but, on account of the peculiar environ-
mental conditions of submerged plants, it can never equal in importance the
absorption of the roots of land plants.”
Tf the submerged species are as dependent upon rooting in the soil ne
my Tesults show, the so-called absorptive function of the root is a vital
necessity and it certainly is not more than this for land plants —RAYMOND
OND.
CURRENT LITERATURE
BOOK REVIEWS
Bacteriology, general and special
Although bacteriology in the past decade or more has developed to such an
instruction in the subject-matter relating to the activities of those organisms that
are of especial moment to him; but in our larger universities the time is ripe for
the presentation of the subject of bacteriology from the standpoint of the student
of general science. A course of training in general bacteriology is as essential
in supplementing a general course in biology as is general chemistry. ‘The works
of De Bary and FiscHer served as a suitable foundation in their day for the
treatment of bacteria from the biologic viewpoint, and there is great need that
such works be brought down to date.
Dr. JorDan, the author of a recent textbook of general bacteriology, has had
an unusual opportunity, by training and position, to develop a strong course 10
this subject; yet one cannot help feeling that even in a university atmosphere,
* Jorpan, Epwin O., A textbook of general bacteriology. 8vo. PP» 557° Ass:
163. Philadelphia: W. B. Saunders Co. 1908. $3.00.
230
59 ae
ae Po ee a
S
3
7
4
'
Te oN eat ee
ei ps ee GN AG ee
1909] CURRENT LITERATURE — 231
receive adequate treatment. Bacteriology will never attain its true position as a
member of the sisterhood of biological sciences until some one of its devotees will
sacrifice his time to prepare a comprehensive text that presents the bacteria in
their relations as living things, rather than as capable of affecting prejudicially
or otherwise man and beast. Special fields may well receive special treatment,
with such summary of general matter as may be absolutely necessary to enable the
special class of students to handle the subject.
While the volume fails somewhat to meet our anticipations and is hardly
adequate from the biologic point of view, the admirable presentation of the
medical part of the volume shows careful work.. The addition of chapters on
the pathogenic Trichomycetes, Blastomycetes, and Hyphomycetes, as well as
the disease-producing protozoa and diseases of unknown etiology, will be helpful
to the medical student in correlating many of the recent advances in microbiology.
With the rapid widening of the scope of study relating to the microparasites, we
shall soon be driven to the adoption of the French term “microbiology,” rather
than the more restricted German title of bacteriology.—H. L. RUSSELL.
The eight years which have elasped since the publication of the first edition
of Conn’s Agricultural bacteriology have been years of rapid advancement in
all lines of bacteriological activity. A second edition? finds much new material
to be incorporated.
he author in his preface admits that the limitations of the term agr cultural
bacteriology are puzzling. The farmer has most of the city problems of sanitation
in miniature and many more in economic bacteriology. The prevention of infec-
tious disease in man and animals; farm engineering with its problems of sanita-
tion, water supply, and sewage disposal; the function of bacteria in the produc-
tion of butter and cheese; the conservation of the soil by encouraging the growth
of beneficial bacteria; the part which bacteria play in the curing and prepara-
tion of food for man and animal—these problems range over practically the whole
domain of bacteriology. A text which attempts to cover such a field in a little
more than three hundred pages must of necessity be an outline merely and not an
exhaustive treatment of the subject. Each chapter could be easily elaborated
Into a volume.
In make-up the volume has improved. The pages have been reduced from
412 to 331 in number. The illustrations have been numbered and many old —
replaced by better. Part, at least, of the decrease in size is due to the elimination
of the references to literature found at the end of each chapter in the first edition.
The text has been entirely rewritten, though the main divisions have remained
as before. The revision has resulted in increased conciseness and clearness of
expression. The discussion of bacteria and the nitrogen problem is excellent for
use in an agricultural high school, but seems rather inadequate as a presenta ore
Of the subject to college students with two or more years of training In chemistry
areaner . , it . x+331- figs. 64.
“ep ONN, H. W., Agricultural bacteriology. Second edition. pp
hiladelphia: P. Blakiston’s Son and Co. 1909. $2.00.
232 BOTANICAL GAZETTE [SEPTEMBER
and biology. A chapter on bacteria and soil minerals has been added. Tuber-
culosis is the only disease which is treated at length. The treatment of acquired
immunity is misleading, in that vaccination is the only method of conferring
immunity which is discussed, and the natural inference is that diphtheria and
other diseases are thus treated. Antitoxins are not mentioned. A part of a
chapter on fungus diseases of plants shows plainly the effect of too much con-
densation. The characterization of wilts, rusts, etc., on page 295 is unscientific
and inaccurate. The student can gain little by a mere list of names of hosts an
parasites such as this chapter contains. ‘There is much that might be eliminated
to make room for more adequate treatment of other subjects. As an introduction
to the subject for the general reader or for the high-school student the volume is
excellent; as a college text, however, it seems inadequate——R. E. BUCHANAN.
NOTES FOR STUDENTS
Current taxonomic literature-—R. Hdroip (Bot. Jahrb. 42:251-334- 1909)
presents a synoptical revision of the American Thibaudieae and carefully tabu-
lates their geographical distribution. One monotypic genus (Englerodoxa) and
67 species referred to 17 genera are published as new to science.—G. MASSEE
(Annals of Botany 23:336. 1909) has published a new genus (Gibsonia) se * F
Ascomycetes; the new fungus was found growing in a drain in North Lancashire,
England.—E. A. Fryer (Bull. Soc. Bot. Fr. IV. 9:97-104. pls. 1, 2: 1909)
describes several new or noteworthy species of Orchidaceae, some of which are
American.—L. A. Dope (ibid. 232-234) has published a new genus (Orias) of
the Lythraceae from China—N. L. GarpNer (Univ. Cal. Pub. Bot. 3:37!-375:
pl. 14. 1909), under the title “New Chlorophyceae from California,” has publ:
two new monotypic genera (Endophyton and Pseudodictyon); a new species
Ulvella is also proposed —O. TscHourIna (Bull. Soc. Bot. Genéve II. 1:98-I0I-
1909) has published a new genus (Astrocladium) of the Palmellaceae. The new
alga was discovered in the vicinity of Geneva, Switzerland, and is represented by
a single known species.—W. BIALOSUKNIA (ibid. 101-104) proposes a new genus
(Diplosphaera) of the Pleurococcaceae, to which is referred but one species
The alga was isolated from the lichen, Lecanora tartarea, and developed as 4
culture.—G. O. (ibid. 182) records a new species of Xyris from Brazil.
V. CaLESTANI (Nuovo Giorn. Bot. Ital. N. S. 15:355-390. 1908), under the title
“Sulla classificazione delle crocifere italiane,” recognizes 31 genera for Italy,
including one genus (Euxena) published as new to science.—R. PAMPANINI
Soc. Bot. Ital. 1908:132-134) describes a new species and variety of Bi sin
indigenous to Mexico.—K. K. MACKENZIE (Muhlenbergia 5:53-58- 1999)
several species of Carex collected by A. A. HELLER in Nevada in 1908 and describes
two new species.—P. B. Kennepy (ibid. 58-61. pl. 2) in continuation of bis
‘Studies in Trifolium” describes and illustrates a new species from Orer
W. Fawcert and A. B. RENpLE (Journ. Botany 4'7:122-129. 1909) in contin’
tion of their studies on Jamaica orchids have published 13 new species belonging
to various genera and one new genus (Neo-urbania); the new genus is based 0°
of
y
j
!
7
‘
—
FE ee PE ET hore ee
1909] CURRENT LITERATURE 233
Ponera adendrobium Reichb.—J. A. Purpus (Monats. Kateenk. 19:52, 53, 89.
1909) describes and illustratés two new species of Cereus from Guatemala.—F.
EIcHLam (ibid. 59, 60) has published a new variety of Mamillaria Celsiana Lem,
from Guatemala.—T. S. BRANDEGEE (Univ. Cal. Pub. Bot. 3:377-396. 1909),
under the title “Plantae mexicanae Purpusianae,” has published 43 species and
one variety of angiospermous plants as new to science, and proposes the following
new genera: Setchellanthus of the Capparidaceae, Acanthothamnus of the Celas-
traceae, and Dichondropsis of the Convolvulaceae.—H. D. House (Muhlenbergia
5:65-72. 1909) has described 7 new species of American Convolvulaceae and
made several new combinations.—B. SCHROEDER (Ber. Deutsch. Bot. Gesells.
27:210-214. 1909), under the title of “Phytoplankton von Westindien,” lists 71
species from West Indian waters, including one new to science.—J. BRIQuET (Ann.
Conserv. et Jard. Bot. Genéve II-12:175-193. 1908) has published 10 new
species and 4 new varieties of Ranunculus and Geranium from Mexico and South
erica.—N. WILLE (Nyt. Mag. Naturv. 4'7:— (reprint 1-21. pls. 1-4. 1909)
describes and illustrates a new genus (Wittrockiella) of the Chaetophorales, repre-
Sented by a single species, W. paradoxa. e material on which the new genus
is based was collected near Lyngor on the southeast coast of Norway. The
author Proposes for it the new family Wittrockiellaceae and states that its nearest
affinity is with the Chroolepidaceae.—E. HassLEer (Bull. Soc. Bot. Genéve IT.
1:207-212. 1909) proposes a new genus (Pseudobastardia) of the Malvaceae
from South America.—H. Curist (ibid. 216-2 36) in continuation of his treatment
of the ferns of Costa Rica, for the ‘‘Primitiae florae costaricensis,” has published
27 New species and one monotypic new genus (Costaricia), also 2 new species o
Lycopodium.—E. L. Greener (Rep. Nov. Sp. 7:1-6. 1909) publishes 17 new
o 4
Jamaica —E, Hasster (ibid. 72-78) has published six new species and varieties
of Malvaceae and Leguminosae from Paraguay and proposes a new genus (Psew-
Pavonia).—A_ LINGELsHEmM, F. Pax, and H. WavKLER (ibid. 107-114), Seen
the title “Plantae novae bolivianae,” have published 20 new species of flowering
Plants.—W. Becker (ibid. 123, 124) records two new species of Viola from Peru.
—E. Parra (Oester. Bot. Zeits. 50:186-194. pl. 3. 1909) has published several
new Cyperaceae, including a new species of Bulbostylis from Bolivia—E. ULE
(Verh. Bot. Ver. Brand. 50:69-123. 1909), in cooperation with several specialists,
has Published 7° new species of flowering plants from South America, based on
Collections made by himself in the region of the Amazon; two new genera are
Proposed: C hamaeanthus of the Commelinaceae and Dolichodelphys ne ct pies
ceae—p HENNINGS (ibid. 129-136) has described several new fungi, including
234 BOTANICAL GAZETTE [SEPTEMBER
a new monotypic genus (Exogone), which the author refers to the Rhizinaceae;
the material on which the new genus is based was found growing on partially
decayed leaves of cabbage——T. Maxrno (Bot. Mag. Tokyo 23:59-75. 1909) in
continuation of his studies on the flora of Japan describes several new species and
proposes a new monotypic genus a of the Celastraceae, based on
Elaeodendron japonicum Franch. & Sav.—W. SuKATSCHEFF (Jour. Bot. St.
Pétersb. 3:124-136. 1908) gives an account of an alga recently discovered in
Lake Lunoevo, Russia, for which the author proposes the generic name Lunoevia;
illustrations supplement the description—V. L. Komarov (Acta Hort. Petrop.
29:179-362. pls. 5-20. 1909) presents a monographic treatment of the genus
Caragana, in which 56 species are recognized, 27 being new to science; the genus
has its distribution through central Asia and China.—E. B. Copetanp (Phil.
Jour. Sci. 4:1-64. pls. 1-21. 1909), in an article entitled ‘‘Ferns of the Malay-
Asiatic region, part I,” including all families of ferns for the region except Hymen-
ophyllaceae and Polypodiaceae, recognizes 22 genera, to which are referred 196
species. The genus Cyathea dominates, being there represented by ror species.
Each genus is illustrated by reproduced photographs, but from rather fragmentary
material.—C. B. Rosrnson (ibid. 69-105) records for the Philippine Islands three
species of the Chloranthaceae, of which one is new, and some 55 species of the sec-
tion Phyllanthinae of the Euphorbiaceae, of which 21 are new to science:—R.
MUSCHLER bes ool 43: Pes 1909); ander the title “‘Sytematische und pflan-
Senecio-Arten,” presents a detailed
cdnsideration of the genus, as ae pertains to Africa, eee about 500 species,
28 of which are here described for the first time.—H. D. HousE (Ann. N. Y. Acad.
Sci. 18:181-263. 1908) presents a monographic treatment of the North American
species of Ipomoea, in which 17 5 species and several varieties are recognized, 3°
being new. The author gives concise keys, rather full synonomy, and numerous
species of Lathyrus from New Masieg aa M. G
Cy y of a Drosera hybrid.—Since the dita’ announcement of
ROSENBERG’s work on the hybrid Drosera longifolia X rotundifolia, cytologis of
have awaited with some impatience the more detailed account, which has ae
appeared.’ —_ Besides giving a comparative study of the external features of =
two parents and their hybrid, the present paper describes the behavior of <
chromosomes in critical phases of the life-history of both parents, and gives
extended account of the chromosomes of the hybrid.
ss sera
OSENBERG, O., Cytologische und morphologische Studien iiber ” pt 4.
loner Kungl. Svenska Vetenskapsakad. Handl. 4321-64 pls.
1909
4
a
Z
*
:
iiss i aati
1909] CURRENT LITERATURE 235
In D. longifolia there are 40 chromosomes in the nuclei of the sporophyte and
_ 20 in those of the gametophyte, while in D. rotundifolia the numbers are 20 and
Io respectively. The chromosomes of D. rotundifolia are somewhat smaller, as
well as less numerous. The behavior of the chromatin in a hybrid between two
such forms is naturally of some importance.
In the hybrid, called D. obovata, the nuclei of the sporophyte show regularly
30 chromosomes, the anticipated number, but in the nuclei of spore mother cells
the condition is unique. At the metaphase of the heterotypic mitosis in the pollen
mother cell there appear 10 double chromosomes, presumably resulting from the
pairing of 10 chromosomes of D. longifolia with the 10 of D. rotundifolia. Besides,
there are 10 smaller single chromosomes, presumably belonging to D. longifolia.
These 10 smaller chromosomes are irregularly distributed; some enter the daugh-
ter nucleus at the close of this mitosis, while others remain in the cytoplasm and
may organize small nuclei, as in the well-known case of Hemerocallis. The
behavior at the second mitosis is similar. The four spores of the pollen tetrad
Stick together, so that it is possible to determine the entire number of chromo-
Somes in the four nuclei. Counting the chromosomes in the four nuclei and
including those of the dwarf nuclei, the number is about 60. In any given spore
the number ranges from ro to 15, with 14 the most frequent. In a preliminary
Paper, ROSENBERG concluded that two of the spores of a tetrad belonged to D.
longifolia and two to D. rotundifolia. This conclusion is now withdrawn, and
differences in the size of spores is attributed to differences in the number of chromo-
somes. Sometimes a generative cell is formed, but usually the contents of the
Spore begin to disorganize before this stage is reached. At the time of shedding,
the pollen grain has a normal exine, but the contents are usually dead.
In the formation of four megaspores from the mother cell the behavior is very
similar to that just described. Occasionally, there is a well-developed embryo
Sac, but in most cases disorganization begins before the four-nucleate stage 1s
reached.
ROSENBERG crossed the hybrid D. obovata with D. longifolia, and while usually
there was no result, he obtained a few embryos. These contained at least 33
chromosomes, and in one case 37 were counted. The theoretical number would
The principal conclusions are (1) that the chromosome is an individual one
of the cell, and (2) reduction of chromosomes is brought about by a fusion of the
chromosomes of the two parents.—CHARLES J. CHAMBERLAIN.
of Alchemilla. In addition to finding that the mildew on Alchemilla is
confined to species of this genus, he also claims to be able to distinguish
minor biological species” within this genus of host plants. For example, conidia
a
*Srerver, J. A., Die Spezialization der Alchemillen-bewohnenden Sphaerotheca
Humuli (DC.) Burr. Centralbl. f. Bakt. etc. 212:677-726. 1908.
236 BOTANICAL GAZETTE [SEPTEMBER
from A. pastoralis and A. flexicaulis are alike in infecting capacity, except that
conidia from the former will only partially infect A. pubescens, and not A. alpigena
at all; while conidia from A. flexicaulis partially infect A. alpigena, A. pubescens
being entirely immune. Another case is that of the mildew on A. impexa which
does not infect A. alpina vera or A. nitida, while conidia from A. pastoralis par-
tially infect these hosts. Otherwise the two mildews are alike. STEINER further
found that conidia from species of the Vulgares group will not produce full infec-
tion on alpine species, although conidia from alpine species produce full infection
on the Vulgares species. STEINER supposes that the mildew on the alpine species
came originally from Vulgares species and is only partially adapted to the ete
osts. He also believes that the appearance of the mildew on alpine species 1S
due to unfavorable environment. me
STEINER also claims to have found “‘bridging species;” for example, conidia
from A. nitida infect A. impexa but not A. fallax, while conidia from A. 1mpexd
will infect A. fallax. Thus the mildew is carried over from A. nitida to A. jallae
through A. impexa. Similarly, A. pastoralis and A. impexa transfer the mildew
from A. connivens and A. pubescens to A. micans. In addition to the fact that
only a few tests were made, STEINER does not tell us what are the infecting powe™
of the mildews produced in this way on A. micans and A. fallax.
His conclusions would be more convincing if based on a larger number of tests.
A large number of foreign infections also occurred in his experiments, no less tha
71 foreign infections occurring in a total of 380 tests. The results are presented
very clearly by means of a series of well-devised diagrams.—GEorGE M. REED.
Cytology of Florideae.—Cytological studies on the Florideae have ge
comparatively rare, partly on account of the difficulty in securing material, bu
principally on account of the difficult technic. Quite recently KursSANOW es
publisheds the results of his studies on three different forms of red algae: ue
minthora divaricata, Nemalion lubricum, and Helminthocladia purpurea. ue
investigations did not deal with nuclear details, but rather with the morphology °
fertilization of the carpogonium, the development of carpospores, and the aes
of the chromatophores. : :
He failed to find a nucleus in the trichogyne of Nemalion and iceman
the trichogyne in these forms seems to be an extension of the carpogonium.
believes that such a condition is found only in the simplest forms of red srt
and agrees with the reviewer that a trichogyne with a nucleus, and yet W! 6 ;
a partition wall between it and a carpogonium, as in Polysiphonia, may The
forerunner of the multicellular trichogyne found in the Laboulbeniaceae- :
spermatium (sperm) has a single nucleus, agreeing with the reviewer's ages
tion of Polysiphonia. He thinks that a uninuclear condition in the spet™ ults
perhaps be universal in red algae. In Nemalion, contrary to WOLFE’S Tes
the chromatophore has, in its center, a well-formed pyrenoid which is com
; 473-330"
5 Kurssanow, L., Beitrige zur Cytologie der Florideen. Flora 99331133
pls. 2, 3. Ig09.
Thar? ee eee,
1909] CURRENT LITERATURE 237
of two parts, a central portion and the surrounding zone. The pyrenoid is
influenced by its environment, and easily becomes swollen and dissolved, leaving -
vacuoles in its place. Such a compound structure of the pyrenoid is shown only
in the stained preparation, and when it is not differentiated with stains the pyrenoid
appears quite homogeneous. ScHuitz’s description of the pyrenoid as a homo-
geneous body may perhaps be based upon the unstained material—Snicto
YAMANOUCHI.
Karyokinesis in Oedogonium.—Since STRASBURGER’S and KLEBAHN’s work
on Oedogonium, there had been little published on mitosis in this form until
WISSELINGH’S paper appeared. STRASBURGER’s material was O. tumidulum Kg.,
EBAHN’S O. Boscii Witte, and WissELINGH’s material was O. cyathigerum
Witte, fixed in Flemming’s solution. After being left in the solution for one
day, it was treated with 20 per cent. chromic acid. By the action of the Flem-
ming solution and the chromic acid solution, the cell wall and cell ¢ontents
become entirely dissolved, and the nuclear membrane is also dissolved by the
action of 20 per cent. chromic acid ‘solution. The chromosomes during mitosis
were studied in their isolated condition.
The chief points of interest are as follows: The mitosis in Oedogonium
agrees with that of higher plants; the development of chromosomes out of the
nuclear network, the formation of the nuclear plate, the longitudinal splitting of
the chromosomes, the reconstruction of daughter nuclei seem like these pr
in Fritillaria and Leucojum, two forms which were also studied by von WISSE-
LINGH. In Oedogonium, the chromosomes, 19 in number, and differing greatly
from one another in length, are connected by fine fibrils, The nucleolus does not
take part in forming chromosomes, but disappears at the beginning of mitosis,
and there appear in daughter nuclei new nucleoli, which later unite into one.—
SHIGEO YAMANOUCHI
Mycorhiza.—PEKLo announces in a preliminary paper’ the results of his
Studies on the epiphytic mycorhiza of Carpinus and Fagus, with brief reference
also to the endophytes of Alnus glutinosa and Myrica Gale.
Tn Carpinus, asa reaction to the penetration of the tissues of the young rootlet,
‘annins increase (as the author has also determined for Monotropa*), and this
Testricts the fungus to the intercellular spaces. Nourishing itself partly on this
Slucoside and other foods in the cortex, the fungus forms the jacket, the outer-
most hyphae of which often die. Isolation of the fungus was finally accomplished
by using a decoction of old thick mycorhizas, which proved very specific for the
Sa easy oe
° WISSELINGH, C. von, Ueber die Karyokinese bei Oedogonium. Beih. Bot.
Centralbl. 2 32139-156. pl. 7. 1908.
"PEKLO, J., Beitrage zur Lésung des Mykorhiza-Problems. Ber. Ie icosua
Bot. Gesells. 27 3239-247. 1909. :
ie a eo » Die epiphytischen Mykorhizen nach neuen Untersuchungen. I. M _
Ypopitys L. Bull. Bohm. Akad. Wiss. 00:000. 1908.
238 BOTANICAL GAZETTE [SEPTEMBER
infecting fungus. In this the inner hyphae began to grow and broke through the
outer layers, and on this mycelium, whose origin was clear, conidiophores and
conidia arose within three days. These showed it to be a Penicillium (Citromyces)
very like P. geophilum, and similar results were reached with Fagus. Fungi 0
this group were also found in the forest soil where mycorhiza of Fagus was abun-
dant. Carpinus was not available for experiments on reinfection, but a consider-
able number of young roots of a two-year-old Fagus showed infection from pure
cultures of the Carpinus mycorhiza, as well as from several other species of forest
Penicillia.—C. R. B.
Respiration.—For about a dozen plants Mme. MaicE has determined the
amount of O, fixed and CO, evolved by the stamens and pistils as compared with
an equal weight of leaf tissue, both in air and in pure hydrogen.? She finds both
aerobic and anaerobic respiration, tested thus, to be much (2-18 times) more
active in the floral organs than in the leaf; and, with one exception, more vigorous
in the pistil than in the stamen, and in the anther than in the filament. These
results confirm the early ones (1822) of DE SaussuRE, as to the relative rate of
respiration of the floral organs and the leaves; but DE SaussuRE found stamens
more active than pistils. For the conciseness of this paper Mme. MAIcE is much
to be commended.
JeNsEN?? finds that the alcoholic fermentation of sugar proceeds by two
Stages and he therefore predicates two enzymes, glucose being split by dextrase
(glucase ?) into dioxyacetone and this by “‘dioxyacetonase” into CO, and alcohol.
But in respiration, with oxidase and free oxygen present, the dioxyacetone, pro-
duced as in fermentation, breaks up into CO, and water, the main end-products of
aerobic respiration.—C. R. B
Transpiration.—Sampson and ALLEN, declaring that too little account has
been taken of the effect of physical factors on transpiration, furnish further data
on this subject.t* Comparing evaporation from equal areas in equal times wid
find that there is little variation for plants of the same species under the same —.
ditions of development and exposure; that of the same species the sun Sn
evaporates 2—4 times as much as the shade form, whether the two are tested in the
sun or shade, a difference which they ascribe chiefly to the greater pees
stomata in the sun form (20-60 per cent.); that the increased evaporation = t
altitude, caeteris paribus, is due to lower pressure and not to differences 1 pe
or humidity; that generally acid solutions accelerate and alkaline solutions re ;
evaporation, but without relation to concentration; that evaporation 1S a
9 MaIcE, Me. G., Recherches sur la respiration de I’étamine et du pistil. Rev
Gén. Bot. 21: 32-38. 1909.
‘© JENSEN, P. Boysen, Die Zersetzung des Zuckers wahrend des RespirationsP
zesses. Ber. Deutsch. Bot. Gesells. 26a:666, 667. 1908.
't Sampson, A. W., AND ALLEN, Louise M. Influence of physical
transpiration. Minn. Bot. Stud. 4:33-59. 1909.
factors 0?
oe ee ee ee a eee er ee en
LO RI TOT en ae
1909] CURRENT LITERATURE 239
from plants in coarse than in fine soils; and that a “bog xerophyte,” Scirpus
lacustris, loses about twice as much water as Helianthus annuus, on account of
its loose structure, the air spaces being estimated at 80 per cent. of the total volume
and the internal surface as 15 times the external.—C. R. B.
Anthocyan.—On the vexed question of the formation of anthocyan, ComBEs
furnishes‘? first a very clear and compact summary of the previous researches.
e then demonstrated that the close relations between the accumulation of
carbohydrates and the formation of anthocyan, pointed out by the researches
of OverToN and Mo iiarp on artificially nourished plants, exist also in nature,
however the pigmentation is provoked. The insoluble carbohydrates behave
differently, according to the occasion of the pigmentation; but the sugars, gluco-
sides, and dextrins behave alike : all cases, the two former varying in amount
directly as the anthocyan, the dextrins diminishing as the sugars and glucosides
increase. The foncluble aie consequently, appear not to share
directly in the formation of the red pigment. Comes concludes that the antho-
cyans, which are probably cyclic glucosides, are formed at the expense of neither
preexistent sugars and glucosides nor chromogens, but arise at the same time
as other glucosides, as part of the general accumulation of such bodies.—C. R. B.
Chlorophyll bodies.—Morphological distinctions between chlorophyll bodies,
found in a great number and variety of plants, have been pointed out by D’ARBAU-
MONT,'3 who divides them into two categories, chloroplasts and pseudochloro-
Plasts. The former, held to be morphologically superior, seem to include the
bodies usually recognized under that name, without admixture of the latter,
om which they are distinguished by not swelling in water (at least im situ),
and by not being stained, with rare exceptions, by acid aniline blue. The pseudo-
chloroplasts, on the contrary, usually swell in water and become vividly colored
in the stain, They are of four types, all small, more or less varied in shape,
with different degrees of green coloration, and variously intermixed. The mem-
bers of the two categories are formed in the same way, either with or without
the cooperation of starch,'4 and both, without reference to their mode of origin,
may or may not form starch.—C. R. B.
ro re of Symplocarpus.—In an investigation of Symplocarpus pres
RosENDAHL'S has obtained the following results: the primordia sea
pein se
‘? ComBes, R., Rapports entre les composés ae et Ja formation de
grates Ann. Sci. Nat. Bot. IX. 9275-303. 1909
3 D’ARBAUMONT, J., Nouvelle contribution a l’é conte des corps chlorophylliens.
Nes Sci. Nat. Bot. IX. 9: 197-229
'4Cf. Betzune, E., Nouvelles vitae sur l’origine des grains d’amidon et
des grains 7 paar Ann. Sci. Nat. Bot. VII. 13:17. 1891; Jour. de Bot.
9: we To2. 1895.
OSENDAHL, C. Orro, Embryo sac development and embryology nee
espa Minn. Bot. Studies 4':1-9. pls. I-3- 1999-
240 BOTANICAL GAZETTE [SEPTEMBER
appear 18-20 months before the pollination period, and the ovules are formed
late during the season preceding pollination; the single archesporial cell produces
four distinct megaspores; an antipodal tissue of a considerable number of cells
with large nuclei is developed; endosperm formation begins with free nuclear
encroaches upon the integuments and the chalaza;-a filamentous proembryo
(2 or 4 cells) becomes club-shaped to ovoid, and a short suspensor of several rows
_ of cells is differentiated from the usual monocotyledonous embryo; in its growth
the embryo completely destroys the endosperm and all other ovular structures,
and comes to lie naked in the cavity of the ovary, so that there are no seeds in the
ordinary sense.—J. M. C,
Morphology of Caulophyllum.—The seed and seedling of Caulophyllum
thalictroides have been studied by Butrers,'® with the following results: the
fleshy testa incloses a very hard endosperm, which has almost completely destroyed
the inner integument; the proembryo is massive and pear-shaped and the cotyle-
dons appear late; the first season’s growth after germination is usually entirely
subterranean, the cotyledons together forming an effective haustorium; the first
leaves are usually scalelike and inclose a winter bud; each cotyledon sends three
vascular bundles into the hypocotyl, which finally form a tetrarch root; secondary
thickening takes place in the hypocotyl, resulting in the formation of a continuous j
zone of xylem about the pith —J. M. C. #
we ee eee
sian
Temperature and locomotion. TEODORESCO reports'? movements in certain =
organisms at temperatures far lower than have heretofore been recorded. Thus
he found zoospores of Dunaliella motile down to temperatures of oe
—22° 5 C., and others at —5° to —12°7 C. The limits vary with species and even
with individuals. There seems to be much more activity in winter, even aa
freshwater organisms, than has been supposed.—C. R. B
_ Carbon monoxid.—Krascuénnikorr, after a careful series of a
reports*® that CO cannot be used by green plants to form carbohydrate. *
view of BoTTOoMLEY AND Jackson,*? which was really not adequately suppo oe
by their experiments, the only ones interpreted in favor of such use, is dis
negatived.—C. R. B. ira
© BUTTERS, FREDERIC K., The seeds and seedling of Caulophyllum thali Ee
Minn. Bot. Studies 4': 11-32. pls. 4-10. 1909. - ¥
‘7 TEopoREsco, E. C., Recherches sur les mouvements de locomotion der sig
nismes inférieurs aux basses températures. Ann. Sci. Nat. Bot. IX. 9:23!-27+ Bate
‘8 KrascHENNIKOFF T., La plante verte assimile-t-elle oxyde de N°
Rev. Gén. Bot. 21:177-193. pl. 10. 1909. i
'9 Proc. Roy. Soc. Lond. 72: 130-131. 1903.
ae Aiticics : Pas TH
: = New Normal Appin Ui
Tbe Botanical Gazette
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ol. XLVII CONTENTS FOR OCTOBER 1909 No. 4
EMBRYO SAC OF HABENARIA (wITH TWELVE FIGURES). William H. Brown = 241
BE INFLUENCE OF TRACT ae ON THE oe ee Acs sinccharmipbeeie wave dhs Sar
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E MODIFIABILITY OF a ION IN batcrhiss SEEDLINGS siaeond FIVE
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eet
VOLUME XLVIII NUMBER 4
BOTANICAL GAZETTE
OCTOBER 1909
THE EMBRYO SAC OF HABENARIA*
Wittram H. BROWN
(WITH TWELVE FIGURES)
The present investigation was made on Habenaria ciliaris (Michx.)
R. Br, and H. integra (Nutt.) Spreng. The development of the two
species is very much alike and the same description will apply to both.
The material was fixed in medium chromacetic and the sections were
Firs = Se Megaspore mother cell in apex of llus.—Fic. 2. Megaspores.—Fis. 3.
division of functional megaspore and three degenerating megaspores.
cut 10 thick and stained with Flemming’s triple or Haidenhain’s
Iron alum hematoxylin.
T The ovule of Habenaria is anatropous and has two integuments.
h he archesporium differentiates in the apex of the nucellus as a single
ypodermal cell ( fig. 1), which is the terminal cell of a row surrounded
No “Contribution from the Botanical Laboratory of the Johns Hopkins > scbieganted
- Io,
24
242 BOTANICAL GAZETTE [OCTOBER
only by the epidermal layer. The archesporial cell without dividing
functions as a megaspore mother cell, which divides to two daughter
cells, which in turn divide to form four megaspores. The last division
may be simultaneous in both daughter cells, but usually it is delayed
in the one nearest the micropyle (/ig. 2).
Soon after the formation of the megaspores the chalazal one begins
to enlarge at the expense of the other three, which soon degenerate.
Before this degeneration has proceeded far the nucleus of the function-
ing megaspore divides (jig. 3) and the two daughter nuclei remain
t.—Fic. 5. Bight
—Fre. 6. ash
a, degenerating
Fic. 4. Nuclei of four-nucleate embryo sac dividing to eigh
nucleate embryo sac: s, synergids; e, egg; a, antipodals; , polar nuclei
bryo sac with fusing polar nuclei; 9, polar nuclei; s, synergids; e, egg;
antipodals.—Fic. 7, Young embryo and degenerating endosperm nucleus.
in the polar positions in the enlarging sac. Each of these two nucle!
by two successive divisions gives rise to four, so that the mature sac
contains eight nuclei (fig. 5). As the sac continues to enlarge, the
nucellar cells which surrounded the four megaspores degenerate, so
that at about the four-nucleate stage the sac comes to lie against -
inner integument. At the last division of the embryo sac nucle! a
two spindles in each end are arranged approximately at right ang ci
to one another (fig. 4). As is usual, the transverse spindle in the micro
pylar end gives rise to two synergids, while the longitudinal on¢ ger
the egg and the micropylar polar nucleus. In the chalazal oe
longitudinal spindle gives rise to the antipodal polar nucleus and
= CRs o 2 en ee ay SY.
3 Ig09] BROW N—EMBRYO SAC OF HABENARIA 243
antipodal, while the other spindle forms twoantipodals. Walls cutting
off the egg, synergids, and antipodals are formed on fibers connecting
the nuclei. Owing to their position nearer the center of the sac,
the polar nuclei are left free in the cytoplasm (fig. 5), as has been
pointed out by STRASBURGER (?05) for Drimys Winteri. After their
formation, the egg and synergids enlarge considerably, while the
antipodals soon degenerate ( jig. 6). When the egg and synergids
have about reached their mature size, the polar nuclei fuse (fig. 6).
No cases were observed in which the polar nuclei were in con-
Fics. 8-1o. Older embryos: s, suspensor; e, embryo.
tact without fusing, as have been described for other forms by
STRASBURGER (700) and Nawascutn (’00). The pollen tube comes
through the micropyle and discharges the two male nuclei into the
embryo sac. One of these fuses with the egg, while the other fuses
with the product of the fusion of the polar nuclei to form the primary
endosperm nucleus. This enlarges somewhat, but without dividing
begins to degenerate at about the time of the first division of the fer-
tilized ege (fig. 7). ee
The first division of the fertilized egg is transverse to the longitudi-
Nal axis of the embryo sac. Of the two resulting cells the chalazal one
244 BOTANICAL GAZETTE [ocTOBER
forms most of the embryo, while the micropylar one gives rise to the
suspensor and a small part of the young embryo. The second division
( fig. 8, wall 2) is in the micropylar cell and is also transverse; the third
division (jig. 8, wall 3) is in the chalazal cell and is longitudinal.
Divisions continue in the descendants of the micropylar cell until a
row of about eight cells is formed (fig. ro). The seven of these which
are nearest the micropyle make
up the suspensor, while later
on the other one divides to
form part of the embryo ( fig.
11). The first division in this
cell may be either transverse or
longitudinal. When the row of
cells derived from the primary
micropylar cell has become
four or more cells long, trans-
verse segmentation begins 12
the descendants of the chalazal
cell (fig. 9), so that this be-
comes cut into quadrants (Jig:
Fic. 11. Still older embryo drawn on a ro). Up to this stage the
smaller scale; the suspensor has elongated. have
, sor
—Fic. 12. Many-celled embryo. embryo and suspen
- remained within the embryo
sac Cavity, but now the cells of the suspensor elongate and the free
end of the suspensor is pushed through the micropyle out beyond the
integuments (cf. shape of cells in figs. ro and 11). The cells of the
embryo undergo further division and form a globular mass; fig: -
represents a young embryo in which walls 1 and 3 correspond to 1 an
3 of figs. 8-11.
Discussion
MEGASPORES
In Habenaria the megaspore mother cell divides to two eet
cells and each of these divides to two megaspores. The nee”
the daughter cell nearest the micropyle is usually delayed until wai
that in the daughter cell nearest the chalazal end. If this delay ae |
carried a little farther, we should have the condition described
4
Sa
a
4
‘
1909] BROW N—EMBRYO SAC OF HABENARIA 245
several other orchids (WARD ’80, STRASBURGER ’84), which have
only three megaspores.
In Cypripedium (PAcr ’08) the daughter cells of the megaspore
mother cell do not divide, but one of them forms the embryo sac. In
this case the question arises as to whether the division of both daughter
cells has been omitted, in the way indicated for one of them in Habe-
naria, and the place of the second “reducing division” changed to the
embryo sac mother cell (the cell within the walls of which the embryo
sac is organized); or whether the first two nuclei of the embryo sac
are, as Miss Pacer calls them, megaspore nuclei. In favor of the latter
view it may be said that the “completion of chromosome reduction”
which takes place in the division of the daughter cell is necessary to
the normal development of the embryo sac. COULTER (’08) thinks
that because chromosome reduction, which is usually associated with
megaspore formation, is necessary that megaspore nuclei cannot be
omitted. On the other hand, the place of reduction is not always
constant, even in nearly related plants, as in the case of Nemalion
(WoLFE ’04) and Polysiphonia (YAMANOUCHI 705). In Nemalion
the fertilized egg divides to carpospores and, according to WOLFE,
reduction takes place in their formation. In Polysiphonia reduction
does not take place in carpospore formation, but the carpospore oe
minates to a plant with the diploid number of chromosomes. This
plant bears not carpospores but tetraspores, and reduction takes place
in the division of the tetraspore mother cell. In speaking of Poly-
siphonia, Yamanoucut says: “The tetrasporic plants may have arisen
by a suppression of the reduction phenomena in connection with the
Carpospore, so that it germinates with the sporophytic number of chro-
Mosomes. . . . . The period of chromosome reduction would be
thus postponed from the carpospore to a later period in connection
with the newly formed plant.” If, as seems probable, the place of
reduction has been changed among the red algae, it is reasonable to
Suppose that it may also have been changed in some angiosperms, and
“specially if the structure in which it normally occurred had been left out
of the life-history of the plant. The leaving-out of the division of the
the mother cell into megaspores would simply be the completion of a
tendency toward the reduction in the number of divisions of the arche-
Sporial cells from the condition in the ferns (where it divides a number
246 BOTANICAL GAZETTE [OCTOBER
of times) to such a condition as Habenaria where the archesporial
cell without dividing functions as a spore mother cell.
The only way in which we can claim that megaspore nuclei must
accompany chromosome reduction is by defining a spore mother cell
as that cell in which reduction is initiated and spore nuclei as the nuclei
resulting from the reducing divisions. The logical conclusion of this
would be to make chromosome behavior the sole criterion for distin-
guishing spores, sporophytes, and gametophytes; but since the four
megaspores and embryo sac of Alchemilla (MuRBECK ’o01) may have
the diploid number of chromosomes, or the apogamous embryos of
Nephrodium (YAMANOUCHI ’08) the haploid number of chromosomes,
we cannot regard chromosome behavior as the sole, if indeed the most
important, criterion for distinguishing any of these structures.
A distinction between the first division of the megaspore and a
division giving rise to megaspores is that while in the first case no cell
plate is formed on the spindle, in the latter case either a wall or a cell
plate is formed on the spindle. This wall may be formed in the
embryo sac when this is derived from more than one megaspore, 4S
is apparently the case in Peperomia (BRowN ’08). The first division
of the embryo sac mother cell nucleus of Cypripedium (PACE ’0
agrees with that of those derived from one megaspore in having 0
cell plate formed on the spindle. ‘
The evidence for either view is inconclusive, but seems to the writer
to be in favor of the idea that in Cypripedium the second division 1)
megaspore formation has been left out, and the place where “ reduc-
tion is completed” changed to the first division of the nucleus of the
embryo sac mother cell.
Lroyp (’02) and Coutrer (’08) have advanced the idea that when -
megaspores are not formed the first four nuclei of the embryo BAC ATE
megaspore nuclei. This is probably true in such cases as Lilium
(CouLTER and CHAMBERLAIN ’03) and Peperomia (BRowN 708), and
as COULTER (’08) suggests in some other sixteen-nuclea bryo sacss
but if the ideas brought forward here concerning Cypripedium 4t°
correct, it need not be of universal application. CAMPBELL ('09)»
however, seems to think that even the embryo sacs of Lilium and
Peperomia are not derived from more than one megaspore.
In discussing the view of CouLrer (’08) that when the megaspore
+a
c
1909] BROWN—EMBRYO SAC OF HABENARIA 247
mother cell does not divide the first four nuclei of the embryo sac are
megaspore nuclei, and of BRown (’08) that the embryo sac of Pepero-
mia is composed of the descendants of four megaspores, CAMPBELL
(09) says: “The generally accepted view that in such cases as
Peperomia and Lilium the embryo sac is a single megaspore formed
without previous division from the mother cell can hardly be admitted
to have been disproved by these recent speculations.” In speaking of
Peperomia, he says that BRown bases his opinion that the first four
nuclei of the embryo sac represent megaspores upon the fact that cell
walls are formed in the first two nuclear divisions in Peperomia sintensit
and cell plates in the same divisions in P. pellucida; while in the third
division cell plates are wanting. CAMPBELL says that since in the last
division, which gives rise to sixteen nuclei, cell walls are formed, “this
seems rather inadequate grounds for assuming that the embryo sac rep-
resents four spores rather than a single one.” The presence of the cell
walls was not the only reason for thinking that the embryo sac of
Peperomia represents four spores; but even if it were, the formation of
Walls in the last division would offer no difficulty to such a view, for
walls are usually formed at the last division of the embryo sac of angio-
sperms and the writer has not been able to find any essential difference
between the method of their formation in Peperomia and in Habenaria.
Nor would the reduction of the free divisions in the embryo sac to a
single one (the third in Peperomia) be a difficulty when we remember
that the number of these is often large but quite variable in the gymno-
sperms and has been reduced to two in the ordinary angiosperms.
The fact remains that unless we assume that the first four nuclei of the
embryo sac of Peperomia and Lilium are megaspore nuclei, we have
no explanation for the presence of walls in the first two divisions of the
‘mbryo sac of Peperomia and for the absence of these walls in the third
division, or for the presence of cell plates on the spindles of the first
two divisions of Lilium, features which have been described in no case,
So far as the writer knows, in which the embryo sac is formed from
one of four megaspores. we
CAMPBELL thinks that if the compound nature of the sac of Lilium
be admitted, we still have to explain the extraordinary departure of
Peperomia from the usual type, but why two such distantly related
Plants would be expected to behave alike is not explained.
248 BOTANICAL GAZETTE [OCTOBER
It does not seem likely that a primitive embryo sac, as CAMPBELL
believes the sixteen-nucleate type to be, has been retained in plants so
far examined only in such distantly related genera as Peperomia, Pan-
danus (CAMPBELL ’09), Gunnera (ERNST ’08), Euphorbia (MopILEw-
SKI 709), and the Penaeaceae (STEPHENS 708); and especially since
most of these genera are anything but primitive in other respects, and
the embryo sac is in most cases derived from a spore mother cell which,
as CAMPBELL says, can hardly be regarded as a primitive feature.
ENDOSPERM
NaWASCHIN (700) finds that in Phajus and Arundina there is no
fusion of the polar or second male nuclei, and he attributes the lack
of endosperm to this cause. STRASBURGER (?00) has shown that in
several European orchids this fusion may or may not take place, but .
in either case there is no division to form endosperm. He concludes
from this that the lack of endosperm is not due to the failure of the
nuclei to fuse. The condition in Habenaria, where there is no endo-
sperm, although the fusion nucleus is of constant occurrence, 15 4
confirmation of this view.
In contrast to Habenaria, endosperm may be formed in Lemna
(CALDWELL ’99) without a fusion of the polar nuclei. ,
In the aposporous embryo sac of Hieracium (ROSENBERG 06)
polar nuclei with the diploid number of chromosomes may fuse 1
form the endosperm nucleus. In all known sixteen-nucleate sacs
all of the nuclei not cut off by walls fuse to form the primary endo-
sperm nucleus. In Peperomia hispidula (JOHNSON ’07) pees
fourteen of these fusing nuclei; while in P. pellucida (JOHNSON 00)
and P. sintensii (BROWN ’08) there are eight; in the Penaeaceae
(STEPHENS ’08) and Euphorbia procera (MopILEwskI ’09) there are
four; and in Gunnera (ERNsT ’09) seven.
The fact that in Habenaria the fusion of the polar and second male
nuclei does not result in the formation of endosperm, while in eRe
endosperm is formed without this fusion, taken together with the 2
that the primary endosperm nucleus may be formed by the fusion 0" @
variable number of nuclei or of nuclei with either the diploid oT ai
loid number of chromosomes, seems to strengthen Se
(?05) view that the endosperm is not a sexually produced embryo
1909} BROWN—EMBRYO SAC OF HABENARIA 249
that the fusion of the nuclei is connected with the fact that the nuclei
have ceased developing and are in the same cell cavity.
Summary
The archesporium of Habenaria arises as a single hypodermal cell,
which without dividing functions as a megaspore mother cell.
The mother cell divides to two daughter cells and each of these to
two megaspores. The division of the daughter cell nearest the micro-
pyle is usually delayed.
In some cases an embryo sac is probably formed from more than one
megaspore; but the condition in the orchids, where there is a gradual
reduction of the divisions of the megaspore mother cell without an
indication of walls in the embryo sac, indicates that megaspore forma-
tion may be omitted and the place of reduction changed to the first
division of the nucleus of the embryo sac mother cell.
The embryo sac of Habenaria contains eight nuclei: an egg, two
synergids, two polar nuclei, and three ephemeral antipodals.
The primary endosperm nucleus is formed by the fusion of the
polar and second male nuclei, but degenerates without dividing.
The absence of endosperm in many orchids offers no support to
the view that the endosperm is a sexually produced embryo.
The fertilized egg gives rise to a long suspensor and a globular
embryo,
: My thanks are due to Professor D. S. JoHNSON for helpful sugges-
tons and criticisms.
Jouns Hopxins UNIVERSITY
Baltimore, Maryland
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- Campsett, D. H., The embryo sac of Pandanus.
36: 205-220. es 6 gee 1909.
4. CoULTER AND CHAMBERLAIN, Morphology of angiosperms 80. 1903.
)
PEE
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w
250
BOTANICAL GAZETTE [OCTOBER
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Yamanoucat, S., The life-history of Polysiphonia violacea. Bot. GAZE
42:401-449. pls. 19-28. 1906. b
, Apogamy in Nephrodium. Bor. Gazerre 45:289-318- Pls. 9 1°
rs >
Pes >» eee i.
ee eon 2 CN EO Meee ae
pe on en
VES
THE INFLUENCE OF TRACTION ON THE FORMA-—
TION OF MECHANICAL TISSUE IN STEMS:
Joun S. BoRDNER
Introduction
The following investigation was directed to a further knowledge
of the influence of traction in the direction of the longitudinal axis
on the formation of mechanical tissue in the stems of plants.
Petioles, tendrils, and roots were not investigated, because the
wo k of HEGLER (9), Batt (1), and Hrpparp (11) was primarily
on stems, and it was my purpose to add further and more detailed
experimental evidence to the work done by these investigators.
This research was carried on in the Botanical Labo atory of the
University of Michigan. It was under the direction of Prof. F. C.
EWCOMBE, to whom I am indebted for encouragement and helpful
Suggestions. I wish, also, to express my appreciation of the interest
manifested in my work by the other members of the staff in the botani-
cal department.
Historical
I. STEMS: INFLUENCE OF TRACTION
BARANETSKY (2) observed that a stem of Gesneria tubiflora
Weighted with 308" made less growth than one remaining free.
ScHOLTz (26) verified this observation of BARANETSKY, and found
that stems when subjected to traction first grew more slowly and
later more rapidly than the control plants. This he att ibuted to a
change in the physical condition of the cell resulting from the educed
ydrostatic pressure. He furnished no experimental evidence to
support his theory. HEGLER (9) produced the first experimental
evidence to show that plants respond to tension by an increased
formation of mechanical tissue. ‘This supported the theory which
Was generally adhered to by plant physiologists previous to that time;
Viz., that a plant reacts toa gradually increasing strain by an increased
___Contribution No. 111 from the Botanical Department of the University of
Michigan.
E351] ! [Botanical Gazette, vol. 48
252 BOTANICAL GAZETTE [OCTOBER
development of its mechanical tissue. In reporting the work of
HEGLER, PFEFFER (21) says that a seedling of Helianthus annuus,
whose original breaking strength was 160%", had a breaking strength
of 250%" after two days under the pull of 150%". No breaking
strength is given for a control. A petiole of Helleborus niger which
withstood a weight of only 400%", PFEFFER reports to have held a
weight of 3.5** after 5 days, during which time it had been weighted
with a gradually increasing load, while similar petioles under normal
conditions gained but little in strength. Changes are also reported
in the anatomical structure: (1) an increase in the nimber of cells
of the collenchyma, (2) an increased thickness of the walls of the
collenchyma, sclerenchyma, and bast, and (3) the production of
entirely new tissues. It is unfortunate that a full account of HEGLER’S
methods and work was not published.
HEGLER (10) showed that the phenomenon observed by BARANET”
SKY and SCHOLTz was not purely physical, but that a physiological
change took place within the cell, due to stimulation coming from
the tension. As evidence, he demonstrated that when plants were
dep~ived of oxygen or when they were under the influence of chloro-
form, there was no response. He also found that the plants under
tension were more turgid than controls, instead of less as ScHOLTZ
had claimed.
RICHTER (25) concluded that when the stems of Chara were
subjected to a longitudinal pull, there was an increase in strength.
BaLw’s criticism of RICHTER’s work is well taken. He says: “Di
Resultate RicHTER’s sind etwas zweifelhaft; da er keinen Vergleich
zwischen belasteten Chara Pflanzen und unbelasteten von demselben
Alter und derselben Grosse gegeben hat.” ss
Kuster (15) found no response, and showed that in the ie
of Helleborus niger the new elements, which HEGLER (91) a
were produced in response to tension, were there before tension? was
applied. PFEFFER (22, p. 148) also found no response in the pro
duction of mechanical tissue in plants subjected to tension.
VO6CHTING (27) investigated the influence of tension on sunfl -
and cabbages that had been prevented from flowering by se A
decapitation. He found that no new tissue was formed, and that »
increase in mechanical tissue occurred as a result of tension.
owers
Igo09] BORDN ER—INFLUENCE OF TRACTION ON STEMS 253
WIDERSHEIM (29) experimented with pendant branches of Fraxi-
nus, Fagus, Caragana, Sorbus, Ulmus, and Corylus. He fastened
weights directly to these branches and continued the experiment
through most of the growing season. Only in the case of Co-ylus
was there any response; viz., an increase in the number of bast fibers.
BALL (1) experimented with Helianthus annuus, Phaseolus multi-
florus, Lupinus albus, Helleborus niger, Ricinus communis, two species
of Cyperus, and Mirabilis jalapa. His conclusion was that these
plants do not respond to tension by an increase of their breaking
strength or by the production of mechanical tissue.
Hrpparp (12) found an increase of mechanical tissue in the stem
of Vinca major when the same was subjected to longitudinal pull.
He failed to find any response in the stems of Helianthus annuus,
Ricinus communis, Brassica oleracea, and Phaseolus multiflorus.
Hrsparp did not determine the breaking strength of his stems.
2. STEMS: THE INFLUENCE OF COMPRESSION; ALSO
COMPRESSION AND PULL COMBINED
Knicut (14) tied a young tree in such a manner that it was swayed
only in the plane of the prevailing wind. After the lapse of one
growing season, the diameter in this plane was found to be greater
than the diameter at right angles to the same.
HIBparp (1 1) found that compression caused a small increase
of mechanical tissue in the stems of F uchsia, Vinca, and Helianthus,
while Coleus gave no response.
3. ROOTS: RESPONSE TO TENSION
Hipparp (1 I) says: “ Pull in the direction of the longitudinal axis
of the plant called forth a small increase of mechanical tissue in the
Main and lateral roots of Helianthus annuus and Ricinus communis.”
4. TENDRILS AND PETIOLES
_Darwin (4; Gray 8, p. 176) says that in the grape-vine,
Virginia creeper, etc., attached tendrils thicken and harden, gaining
wonderfully in strength and durability, while those which remain
“nattached soon shrink up or wither and fall off.
_ Mitier (18) found that contact produced earlier and greater
lignification of the sclerenchyma, even in the free portion of the ten-
254 BOTANICAL GAZETTE [OCTOBER
drils of the Cucurbitaceae; but he did not consider tension as a
probable factor along with contact. , ;
Worcitzky (30) reports that tendrils of Passiflora quadrangularis
which had grasped a support broke at 600%", while the controls broke
at 350%". With tendrils of Cucurbitaceae, the uncoiling resistance
was thirteen times as great in those which had grasped a support.
There was also a marked anatomical change; viz., a lignification of
the pith parenchyma, which he assigned to no cause.
Von DerscHau (28) found that a gradually increasing pull on
certain twining petioles raised their breaking strength and caused
an increased development of mechanical tissue. He found a nu-
merical increase in almost all kinds of cells. The petioles of Solanum
jasminoides showed the least response. ;
NEWCOMBE (19, p. 446) says, in speaking of the reaction of tendrils
to contact: “The first strengthening tissue is here laid down as 4
Tesponse to contact; its increase is the regulatory response of the plant
to the strain that it feels.’ See
MacDoveat (17, pp. 377, 378) believes that contact stimuli oe
not transmitted beyond 2 or 3™™. Since the thickening of the wee
always takes place after contact, the natural conclusion would be tha
this thickening of the tendril is due to the traction exerted by the
weight of the stem supported by it. ee fe
PEIRCE also (20, p. 241) believes that the strengthening ©
free basal portion is not due to contact. iin
FITTING (6, p. 476) has demonstrated that contact stimuli ee
transmitted to the basal portion of the tendril, and that therefore .
effect of contact stimuli on the basal portion of tendrils cannot
. excluded.
5. CORRELATION
The factor of correlation has been investigated by eget
workers. Since self-regulatory development may imply 4 " of
degree of correlation, it seems desirable that at least a brief review
the work on correlation should be given. : cture
Laporte (16) found decided differences in the anatomical =~
of the floral axis compared with the rest of the plant: (1) 22 (3) 8
of bast, (2) a decided modification of the main bundles, and (3
decrease of pith.
LE ee ee ee ee
Ig09] BORDNER—INFLUENCE OF TRACTION ON STEMS 255
KLEIN (13) found the bundles more centrally located in the fruit
stalk than in the petiole. He attributed this arrangement to the
necessity for a greater mechanical strength, as well as for a more
abundant supply of building material.
DENNERT (5) compared the anatomical structure of the fruit
stalk before and after the ripening of the fruit. He found an increase
in the development of mechanical tissue. There was an increased
amount of xylem anda greater thickness of the walls of the wood
fibers.
REICHE (24) investigated the transformation from flower to
fruit stalk in many additional plants. His conclusions agree with
those of the earlier investigators.
PIETERS (23) showed that one-year-old fruit-bearing shoots of
the apple and the pear had a smaller xylem cylinder in proportion
to their diameters than the vegetative shoots of same age. They were
well supplied with supplementary mechanical tissue, however, which
was distributed at those points where it was most needed. In the
case of the peach and the plum, the woody cylinder of the fruit-bear-
ing shoot was larger than in the vegetative shoot. There was an
abundance of well-lignified sclerenchyma and hard bast in the fruit-
bearing shoots of the apple and pear, while in the vegetative shoots
these tissues appeared only sparingly, if at all.
GOEBEL (7, p. 206) writes: “Careful research demonstrates the
existence of reciprocity between parts of the plant body... - .
The size and construction of one organ are frequently determined
by those of another.” : ;
BoopLe (3) states that the walls of the sieve tubes and companion
cells in Helianthus annuus become lignified as a result of strain.
He also found a slight lignification of the parenchymatous 7
of the pericycle and medullary rays, thus uniting the primary
sclerenchyma strands into a more definite mechanical system attached
‘o the strong xylem by the medullary rays. He says: “This must
Sive greater rigidity, which no doubt is required by the heavy fruiting
‘apitula borne by the plants.”
KELLER (12) reached conclusions directly opposed to those
teached by Boopte. He showed that a strong or light pull in the
direction of the longitudinal axis of orthotropic flower stalks exerted
256 BOTANICAL GAZETTE [OCTOBER
no influence on the development of mechanical tissue. The dis-
placement of orthotropic flower shoots to a plagiotropic position,
he claimed, caused a certain anatomical change. This he attributed
to the change in position and not to tension. His conclusion does
not agree with those of other investigators, viz., that mechanical
development of the fruit stalk goes hand in hand with the develop-
ment of the fruit. :
Methods
In both greenhouse and field culture a much larger number of
plants were grown than were used in each experiment. At the begin-
ning of each experiment the strongest plants and those most nearly
equal in size were selected, and the others were removed. This was
done to reduce the chances, as far as possible, of individual variation.
In the greenhouse cultures, the pots with the plants were placed in
a row. The plants were then measured and every other one was
taken as a control. At the close of the experiment, an average Was
taken of all the data on the control, and also the experimental plants
in each series. This was the method used by Scuortz. By pre
liminary experiments, the writer was convinced that it was by far
the most satisfactory, on account of individual variations in plants
which make it very difficult to select any one plant that will be a fair
control throughout the experiment for any one experimental plant.
The methods of Batt and Hreparp for applying tension by pull
in the direction of the longitudinal axis of the stem were followed.
The writer was soon convinced, however, that for plants as large
as those used in his experiments, the leather noose used by BALL #
a tension fastening was not needed. Heavy cotton flannel and ordi-
nary cotton cord, therefore, were used for this purpose in all these
experiments. A strip of heavy cotton flannel 2.5°™ wide was wrapped
at least twice around the stem. Over this, two cords were P@5*
from opposite sides and back again. Each cord, thus passing twice
around the stem, was drawn tight enough to keep the fastening from
slipping. The ends of each cord were then tied to a second.
were united into one strand some distance above the fastening. : av
double cord was passed over a light running pulley, supported direc
above the plant, and a weight was attached to its free end. At
1909] BORDNER—INFLUENCE OF TRACTION ON STEMS 257
strip of wood or bamboo about 1oc™ long was placed crosswise
between the cords coming up on opposite sides of the stem,'to keep
them from injuring the young leaves and growing tip of the stem.
In the field cultures, exactly the same methods were followed,
except that the seeds were planted in rows. The inferior seedlings
were removed, and only the stronger ones were left for experimental
use. In most cases the heavy clay loam was sufficiently firm to keep
the plants from being pulled up by the tension. In the few cases
when the soil was not firm enough, heavy flat weights were used to
hold it in place.
METHODS IN FINAL DETERMINATIONS
Method 1.—In all but two experiments the stems were tested by
direct pull along their longitudinal axes to determine whether they
had responded in a self-regulatory manner to traction by increasing
their breaking strength.
Preliminary experiments convinced the writer that the method
of obtaining the breaking strength used by BALL was not satisfactory, _
since too many of the experimental plants broke at or just below
the tension fastening. Larger plants therefore were used. These
were broken at some distance below the tension fastening, thus elimi-
nating the unquestionably weakening effect coming from the pressure
of a tension fastening on the young and tender stem.
For this purpose, a strong wooden frame was constructed, about
t20°™ long and soc™ high. Through the middle of the frame ran
a shelf parallel with top and bottom. On this shelf rested the plant,
blocks, and spring balance used in determining the tensile strength.
To Stasp the ends of the stem, 4 blocks of wood were selected, each
ing 5°™ thick, ro°™ wide, and 20° long. These blocks were laid
together in pairs, one block above its mate, and grooves considerably
larger than the stems were cut in the contact faces of each pair to
Téceive the plant stem.
_ During the preliminary experiments, the stems, except in the por-
ton to be tested, were wrapped in moist cotton and then imbedded
‘a damp mixture of sand and Portland cement. This mixture
"as placed in the groove of the lower half of the pair of blocks. The
stem was then placed in position and more concrete was piled on top.
258 BOTANICAL GAZETTE [OCTOBER
This was pressed down and around the stem by tightening the bolts
which were used to draw the two blocks together. This method was
satisfactory. It was soon found, however, that the stem could be
held sufficiently firm by substituting moist cotton for the mixture of
sand and Portland cement. Moist cotton, therefore, was used in all
the experiments as packing to fasten the stem in the blocks.
When the stems were fastened in the blocks, one pair of blocks
was hooked to the spring balance, and the other pair was secured
to one end of the wooden frame. The spring balance was hooked
in turn to an iron rod passing through the opposite upright of the
wooden frame. On the end of this rod, protruding beyond the frame,
was a large tail-nut. By turning this tail-nut with the hand, tension
was brought on the spring balance, and through the balance on
the plant stem. The breaking strength was read from the face of
the spring balance.
: After the stems were broken they were preserved either in 50 per
cent. alcohol, or short sections were cut from just below the breaking
point in the stems, and these were killed and fixed in 1 per cent. chrom-
acetic acid, thoroughly washed, dehydrated in alcohol, and kept for
future study.
The following methods were used in making microscopic examina-
tions and measurements of the xylem and hard bast in the stems. 2
Method 2.—Measurements of the thickness of cell walls in sae
free-hand sections, and also in some cases of microtome sections,
were made by using an ocular micrometer. The results record
are in each case an average of eight measurements taken in as many
distinct areas of the cross-section. oa
Method 3.—The total xylem and hard bast areas were meast :
in some of the experiments by projecting a cross-section of the
upon a bristol-board screen, and measuring the areas with a po
planimeter. . fe
Method 4.—Camera lucida drawings of the total xylem an i
bast areas and also of the hard bast elements were made upon oe
ardized bristol-board. The drawings were very carefuly cut ‘
with a sharp and pointed scalpel, and then weighed on @ ir ~
balance. The number of hard bast elements were also count ae
fastening the drawings of the hard bast elements over sheets of y
Le Ay Rae een ea ee
Caudle aes
vail
soak J
GS ticks
aA fhe
r909] BORDNER—INFLUENCE OF TRACTION ON STEMS 259
paper and checking off each element by marking through the lumen
on the yellow paper underneath.
Method 5.—The hard bast elements were drawn by means of a
camera lucida and then counted to determine whether an increase
had resulted in response to the pull.
Method 6.—Radial and tangential microtome sections of acid-
fixed material were made to determine whether any fibrous paren-
chyma existed directly around the hard bast areas. This method was
used only on control stems of Helianthus annuus. It was the purpose
to determine whether the elements which produced the increased
number of bast fibers were present before the tension was applied and
therefore only developed, or whether they were formed de novo in
response to tension.
The plants investigated were Helianthus annuus, Phaseolus vul-
garis, Ricinus communis, Sinapis alba, Vicia Faba, Lupinus albus,
Rubus occidentalis, and Vinca major.
Experiments
Experiment 1. Helianthus annuus, greenhouse culture.—Ten
vigorous plants were selected from a number of seedlings grown in pots
20°" in diameter. The experiment began November 21, 1906, when
they were mostly ro to rs°™ in height, and ended 29 days later. The
tension fastening was placed on the experimental plants just below
the second pair of leaves. The controls were not supported. The
pull applied to the experimental plants was gradually increased from
25%™ at the start to 300" on December 14, 1906. The slow growth
of these plants may be due to the fact that during the entire experi-
mental period there were only a few sunny days, and also to the short-
hess of the day at this season of the year.
_ Table I gives all the data from this experiment, except the follow-
ing: By method 6, fibrous parenchyma was found in the control stems
as a transitional form between the thick-walled hard bast fibers and
the short-celled parenchymatous tissue. These longitudinal sections
vere taken from just above the cotyledons. The increased number
of bast fibers in the experimental plants, therefore, may be accounted
lor as the result of the response of these fibrous cells to tension, which
thus develop into hard bast fibers. ee Hace
260
BOTANICAL GAZETTE
[OCTOBER
The actual area of the cell walls of the hard bast elements and
their number was found by method 4, and the total xylem area by
method 3.
TABLE I.—Helianthus annuus
ae A
NOVEMBER NovEMBER DECEMBER DECEMBER A |82h [ea] so
21 28 14 20 im at aes Bet. ee
No. or —| 25 |g82 188) =x
PLANT G22 seb Zi we z¢
Height| Diam.) Height | Diam.| Height | Diam.|Height| Diam.| 224 |3583/ 0%) #2
in in in in in in in in | BES |qons] oa] Fe
cm. mm. | cm. mm. | 4 ‘) ZA | we
Exp. 8
ee 19. | 4. | 29. | 4. | 50.4] 4. | 59.2] 4.2 | 7711] 6.837) O91 ce
Gr 15600) 9.24 3g. ER dae Be 4.1 | 41.6] 4.2 | 5443] 7-014} 811) ©.
eG ks 10.6 | 3-5 | 19. | 3.5 | 37-8 | 3.6 | 44.7] 3.5 | 5216] 6.430] 840 25
4...+.|/11.8 | 3.1 | 20.7 | 3.2 | 35.3 | 3.6 | 44.1] 3.9 | 4626] 5.488) 682) 5.
ere Q. 2. 20.2 | 2, S625 53. 44.1| 3.2 5443) 5-666 ds Baeall
Total |63.5 [15.8 |107.9 (15.9 |194.0 |18.3 |233.7|/19.0 287.49|31 -435|3005|33-5_
Av....|12.7 | 3.16) 21.58] 3.18] 38.8 | 3.66/46.74 3-8 |5749.8| 6.287) 721 ot
Control 6.6
ere 15-2 | 3. | 22.7 | 3. | 42.8 | 4.1 | 52.9] 4.3} 5352] 5-145 39 3
Pe: Joe ee ee yee oa eee oe a eee 3039| 6.420 ; a
Toss 11.3] 2.5 | ¥9. -| 3: | 34. | 3.4.| 41.6] 3.5. | 3729] 5-374] O57 7
Bee, Ir.3 | 3-2 | 18.3 | 3.2 | 34. | 3.2 | 39. | 3-5 | 2494] 5-498 or e
Sao Q- | 2.2 | 12.1 | 2.2 | 23.3 | 3.2 | 30. | 3.4 | 3629] 4-679] 950) 3
Total |58.6 |14.4 | 89.7 [14.9 |168.1 17.7 |206.3/18.5 | 18233 27 .114)324823-8
———- ; 6
Av 11.72) 2.88) 17.94) 2.98] 33.62] 3.54|41.26| 3.7 3647] 5.423] O48] 47
The percentages of increase in the experimental plants over the
controls are the following: breaking strength 57.6 per cent.; cross
section of walls of hard bast 16 per cent.; number of hard bast ele-
ments 12.5 per cent.; and xylem area 4o per cent.
TABLE Il.—Helianthus annuus
paver an ay
i Dis- reak
Height] Di ee
No. of eats ad_| above rst pait | Oren yistrength
plant Height in cm. pair of ror nee below ad in kg
a ae ree
aU uly
June | June | June | June June | June | July | July | June | July od .
Exp. 21 -| 22 4 26 28 30 I I 21 < ax [16.535
Av..... 7-5 | 8.6 |12.6 |16.3 19.4 {23.8 |26.6 |10.4 | 4-1 7-26) 3- 5
Con 13-799
AX ae 7-03) 8.2 |11.3 |14.3 17.3 at.5 |24.3 | 9.2 | 4.1 | 7-43 3-7? pees
eS Ye
1909] = BORDNER—INFLUENCE OF TRACTION ON STEMS 261
Experiment 2. Helianthus annuus, field culture. — After the
inferior plants had been removed, those used in this experiment stood
15 to 20°™ apart in the row. Every other plant was used as a control.
The tension fastening was placed just below the second pair of leaves
on the experimental plants. The control plants were left free. The
experiment began June 21, 1907, and ended ten days later. A tension
of 250™ was applied to the experimental plants at the beginning of
the experiment. This was increased to 750%™ the following day and
to 19008™ on June 25.
Table II gives an average of the measurements and the breaking
Strength of these plants. The average increase in breaking strength
for the experimental plants over the controls was 2736%™ or 19.6
per cent.
The height measurements in this experiment confirm the work
of ScHoitz and HEGLER (’93), showing a lessening of growth during
the first 24 hours, followed by an increased growth for the next four
ays.
TABLE III.—Helianthus annuus
Dis
Diam. just . Just, tance | Break-
No. of : Height to 4th above rst pair above 2d pair |of break} ing
: Height in) eam, i f leaves above _|strength
— pair of leeves, | of pes eee ee ae
in cm
Nie Eee ee i ed ew ad
July | July | July | July | July | July | July | July | July | July
Exp. I 30 18 18 Ric) 18 fo) 3! Pd
Av........] 36.07] 89.6 | 32.33] 44.6 | 9.4 | 15-95] 7-58 | 13-39] 12-3 | 69-99
Control 3
AVeos- 5, 38.01] 90.5 | 34.6 | 45.08] 9.64 | 16.03] 7-69 | 14.37) 13-9 “12
ee Ries ee as ee
Experiment 3. Helianthus annuus, field culture——Much older
and larger plants than those used in experiment 2 were put under ~
tension July 18, 1908. This was gradually increased from 200%"
at the start to r950%™ on July 27. The experiment ended July 3o.
It was the purpose in this experiment to determine whether the same
tension would have the same influence on larger and older stems as
On younger and less woody ones. The average increase in breaking
Strength as shown in table III in response to a tension of practically
T900%™ was 3.87%, while in experiment 2 the increase for a period
Of Io days was 2. 74*s, The increase as a percentage of the average
262 BOTANICAL GAZETTE [OCTOBER
breaking strength of the controls in this experiment, 5.8 per cent.,
was much less than in experiment 2, since the breaking strength was
so much greater.
The tension fastenings were made just below the fourth pair of
leaves. Similar fastenings were made on the control plants, and
from these the plants were fastened to upright supports to keep them
from being swayed by the wind.
Experiment 4. Sinapis alba, field culture.—These plants grew
approximately 15°™ apart in the row. Every other plant was used
as a control. The tension fastening was placed just below the
seventh node above ground. Similar fastenings were placed on the
control plants. From these fastenings, the plants were attached to
strong cords, stretched one on each side of the row and parallel to it.
A weight of 250%™ was attached to the experimental plants on July
16, 1907, and gradually increased to 1150%™ on July 24. The expen-
ment ended two days later. The details of this experiment are giv
in table IV. The average increase of the breaking strength of the
experimental over the control plants was 4.8*% or 32 per cent.
The anatomical structure of these stems was determined by
methods 2, 3, 4, and 5. Free-hand sections were made of all the
stems about 5™™ below the point where they broke. These sections
were stained in anilin safranin and mounted in glycerin. All the slides
were then taken by a second party who labeled them with a secret
label. The measurements given in table IV were then made, after
which the second party gave me the key to the labels. The measure
ments of the experimental plants were now separated from those of
the controls. An average of each set shows a decrease of 10 per cent.
in the total xylem area and an increase in the thickness of the xylem
cell walls of 5 percent. The increase in hard bast in 5 stems which
were selected wholly by chance was 52 per cent. The increase ©
hard bast elements in the same stems was 38 per cent.
The total xylem area for the five stems in which the hard bast
determinations were made was also measured by method 4 <
results that agreed within less than one-half of 1 per cent with the
measurements made by method 3.
The hard bast in the controls was lignified in all but a few ste"
where it was only partly lignified. Stem 18 showed the least
Diam.
abo
ground in
mm.
seseee
weseees
ene oe
oe eevee
ee
Ceereen
see eee
ees eee
eerene
a
te eveee
eee eae
49.791
July
16 26
6.85 ‘
5.1 Oe
5. 6.07
4-65) 7.5
5-2 7:15
5:95 | 8.8
7-2 9-35
7-4 9-9
7-45 9-33
6.05 7.32
5.85 8.3
6.55 8.65
5:75 | 7-6§
6.45 8.1
5-4 5:77
47. 6.75
4.6 5.2
5.35 ors
4.1 YP
109.3 | 145.99
5:75 | 7-68
8.158
{6061
Xylem area in
sq. cm. X10
SHALS NO NOILIVAL O JINXATANI—NA NANO
fgz
TABLETIV.—Sinapis alba (continued)
ne g fs ga as e
: m4 Diam. just scat iD z 2 Ge 3 =
No, of plant Height in cm. tc ei a4 e ve BEGs - 3 26 » : eae
os a mmm” = | GHEE | Gey | Sosa | See | fe | peg
QO io} 6 ae > ES
A Fa s 4 ee Sapa
: Contedt Jit July oe auy ord July ae July July July as July
RRS SE a Aang 23.4 55-5 20. 24. 5.10 725 T5 Dh IE a eae y tore Po ess)
MO ton, 1, 26.3 63. 20.5 aa'.5 6.10 8.do ie EUSP 0 te sada | Ia aa 11.43 | 3.062
AE RCN EA RR ape 172 50. T4025) 089.5 4.15 5.75 ses LES 4 Re Be CaS ae Ap 81 2.562
Be eae clas 6's 20.3 63. I5.4 19.5 5.60 7.708 eae TAEDA ss ss oe P2535 4(:) 087
Pees 9 no eles + 18.8 58. 14.5 19.5 5-35 8.90 bre. 19.94 | 7-075 542 I2.70°|° 3;062
Me aces sys 26. 60. 22.5 34. 8.00 | 10.62] 19. ore is ne ae 19.05 | 3.000
SE HA a2. 64. 7.5 21.5 7.20 9-35 TO; Ir.79 | 4.714 365 16.51 2.562
Pe Es 24.4 63. 19.5 22’. 6.20 5.73 ae ED meee ete eset 8 vs 7.:625| 3.000
Me Statin eon Was 21.7 66. 16.3 22. 7.00 8.63 5 DOOM ale ate ss 10.80 | 3.062
Be ee es us 26.3 66. 22.2 3.5 chr as I0.30.;| ‘Io rer iie fie || Pee: | area | 19.69 2.437
PE ln OL A NaS Bie 21.9 58. 18.0 20. 5-15 6.10 8 oR Wa fee eta fics sc 3 6.35°1° 3-437
11 AGS ARI Sse ree 28.5 70; 28.3 34-5 6.30 LOO A. 7 19.03 || ° 5.700 510 S2a50| 2.e75
ae ays eis» 6 28.7 62 aia 24. 5.60 025 7 TT AG a rome ten swiss «ts :35 | 4.062
PR ees 25.8 66. 21.5 28. 5.80 Popa a8 MODAL ene a liaise. 3s BXs43-) 9.378
EE a7 79. 275 24. 5.00 6.55 8 12.68 | 5.040 491 6.67 | 3.125
eee ye Cav we ois 24.5 57. 20.5 24. 6.10 7.80 yi payee | sa el ee ae II.43 2.500
Lk OSE Sas ee S136 bale 25.0 a7 5-20 O.00|- 12 Bo OMR eee Hedfi. sys «3 6.03 | 3.062
Bee eae is. 26.3 5I. 21.8 23. 4.40 Bsouh 13 Si Saal TSO 395 8.89 | 2.500
ee sis ba 26.5 6r. BS 24. 5-40 ToAS 8 FASB OM ne con sck ole wae 13.07 3.500
«Reo a age aaa 19.5 o2. 16.3 20. 4.80 0.104) Io TS ROWae Math ses os 135397 2.561
396.9 | 486.5 | 115.60 156.92 | 225. | 298.60 | 26.697} 2305 868
24.4 61.8 19.84 | 24.32 5.78 | 7.85 | II.25 14.93 | 5-339|
tgz
ALLAZVI TVIIN VLOG
_ Igog] BORDNER—INFLUENCE OF TRACTION ON STEMS 265
cation among the controls. Stems 5, 7, 12, and 1 5 were all well
lignified. The hard bast in approximately ro per cent. of the experi-
mental stems was completely lignified. In the five stems for which
the hard bast determinations were made, only a few elements were
lignified in 8 and g, while in 16 lignification of the hard bast was
almost complete.
Experiment 5. Phaseolus vulgaris, greenhouse culture.—The
plants for this experiment were grown and selected in a like manner
to those for experiment 1. The tension fastening was placed just
below the second pair of leaves. The experiment began October 21
and ended November 8, 1907. The weight attached to the experi-
mental plants, 400%™ at the beginning, was increased to g50%™ after
five days, and to 11 50%" November 5. The controls were left
unsupported.
TABLE V.—Phaseolus vulgaris
| a 4 :
| Height to Diam. just iam. ge er 2 : z E
No, of Height in 2d pair of above above coty- =; Se |& 5 M, ~ g2
Plant cm. leaves in ground in ledons in os | Seale a Bax
cm, mm. mm. ga | Suz] FX) 38
AY a) rs) 4
Oct. | Nov. | Oct. | Nov. | Oct. | Nov. | Oct. | Nov. | Nov. | Nov. | Nov. Br te
Exp. 21 8 21 aI 2r 8 8 8 4
(5 13.5 |25-. fEQ.E |a4ct [ds gala, Bap Sed fe wee 6.795|88.08) 6.59
Control
BV nas 13.3 {20.8 |12.0 |12.8 | 4.16] 4.53] 2.98] 3.34|-.--- 5.098|76.57| 5-42
The average measurements and results of this experiment are
given in table V. The breaking strength shows an increase in the
€xperimental plants over the controls of 1.7**, or 33 percent. Sec-
tions taken just below the breaks showed an increase of 15 per cent.
in the area of hard bast, and 22 per cent. in the area of the xylem.
hese measurements were made by method 3. The hard bast and
xylem were equally lignified in experimental and control plants.
Experiment 6. Phaseolus vulgaris, greenhouse culture.—These
Plants, when the experiment was started, were ten days older than
those used in experiment 5. The experiment began December 7,
‘997, and ended January 7, 1908, at which date most of the blossoms
had already fallen from the plants and the leaves were beginning
lose their chlorophyll. A weight of 250%™ attached to the experi-
266 BOTANICAL GAZETTE [OCTOBER
mental plants at the beginning of the experiment was gradually
increased to goo#™ on December 20. It was the purpose of this
experiment to determine, by prolonging the experimental period and
growing the plants to maturity, whether the response in the earlier
and actively growing period was continued to the end of the vegetative
period. For this reason no additional weights were added after
December 20. Both experimental and control plants broke with
almost the same weight. The experimental plants were much more
brittle and in most cases broke with a smooth, clear break, while the
controls showed more of the elasticity and toughness which was
characteristic of the stems in experiment 5.
Experiment 7. Phaseolus vulgaris, greenhouse culture.—After
finding that response to tension, if any had occurred in experiment 6,
was vitiated by permitting the plants to grow to maturity, experiment 5
was repeated, beginning March 5 and ending fourteen days later. The
weights used, 2008™ at the beginning, were increased to 4508" March
g and to 7oo®™ four days later. The experimental plants showed an
average increase in breaking strength of 3.32*¢, or 42.5 per cent.
The number of hard bast elements was determined by method 5.
The experimental plants showed an average increase of 167, Or 14.9
percent. The results of this experiment, therefore, agree with those
of experiment 5. The tension fastening in this and also in experl-
ment 6 was made at the same place as in experiment 5.
Experiment 8. Vinca major, greenhouse culture.—In selecting
plants for this experiment those were taken which had young and
actively growing shoots, uniform in general appearance and length.
No measurements were taken at the beginning of the experiment,
December 1, 1906. The experimental shoots were put under a tension
of 50®™ at the beginning, which was gradually increased to 300°" 0?
December 21. The control plants were fastened to an upright suP-
port, but were not under tension. tee
The breaking strength was tested in the internode just below the
fastening which was in an active growing condition in each plant
when the experiment was started. The average shows an increase
the experimental plants of 649%™, or 15.2 per cent.
Experiment 9. Vinca major, greenhouse culture.—It was -
purpose ofthis experiment to determine whether internodes which
~ . pingip' te Mens Ue oT Si
Wee SU Ss ey tr ee kere
:
4
‘
4
1909] BORDNER—INFLUENCE OF TRACTION ON STEMS 267
were no longer elongating would respond to tension by increasing
their breaking strength. For this reason, shoots older and larger
than those in experiment 8 were used. The controls were supported
as in experiment 8. A weight of 200%™ attached to the experimental
shoots on November 15, 1907, was increased to 400%™ on December
14. The experiment ended January 8, 1908.
The third instead of the last internode below the tension fastening
was tested for its breaking strength. No elongation and in many
cases no growth in diameter took place in this internode. An average
of the breaking strengths shows no response to tension for an internode
which is no longer actively growing.
TABLE VI.—Vinca major
Recorp A
2 SSE ac EE, —=- aioe mee ;
| we laeel| So = / g g
| par 32 |eti 2 |g | £2 | 2
| | Height to | nam just| ~e |oe8] # $8 Pe oe n
+ | * - Just Mite: Ss o= ey 2a
No. of Height in ore et below 33 os 2 Ae 5 x) = 23 5 EE
Plant | cm, Siepouskd fastening | fo | 88'S) Ga laee| #7 | eoel| wo
fastening rsh we | eo) 2 ese} ae | EB Ca
: in cm. C8 |Smu/ 3 os 22 we . 3
| in em, sa |2ee| Bs |2 a a 258 64
| Fa a = o 2 a A
Bel | | | Be BPSATS rai!
Jan. | Jan. | Jan. | Jan. | Jan. | Jan. Jan.
Pat 9 25 ° 25 9 25 | 25 }
AY. . “|29- |41.4/25.6/27.3 2.11|2.22| c ereaet 8.25 ee ee bipage. pee e eee:
Control | | |
Vi, aa \44- /28 4/29 6/2 og}2 70) : 8.75 pee. | peers | Par er ke ie er Se a Be
A eg shee | ey ee Be Peeirees Were: ae Vinee SAR LT Ps. a ee eee ea
Recorp B
l Sopsees WED a
I Mar. | | Mar. Mar | | Mar. | Mar.| Mar. | Mar. | Mar. _
Exp. rest et byes es 2 fe
BY: . -|29.2195. 2 del bag sad act dese 15 | 8.22] 5.77] -2777| 7-42 | 127
Control | | } |
Ay. + |28.6)62 26.|28.5 as 2.321 eo 52:3 6-97 509) ae 6.56 | 1297
| | i Berens
Experiment 10. Vinca major, greenhouse culture.—This experi-
ment was in large measure a repetition of experiment 8. -Tension
fastenings were madé on all the shoots. Just enough weight was
attached to the control shoots to hold them erect. The experiment
began January 9, 1908, with a weight of 250®™ attached to the experi-
Mental plants. This was increased to 450%™ eight days later, and to
gooe™ January 25. The internode to which the tension fastening was
attached was in each case actively elongating at the beginning of the
268 BOTANICAL GAZETTE [OCTOBER
experiment. One-half of the shoots were removed and tested January
25,1. ¢., after 16 days and subjection to a maximum tension of 4508".
Table VI, record A, gives an average of the results for this part of the
experiment. The average breaking strength is slightly increased in
the experimental shoots.
The remaining shoots were tested March 2, 1908. An average
of breaking strengths as given in table VI, record B, shows an increase
in favor of the experimental shoots of 1.25" or 18 percent. A study
of the anatomical structure of these stems was made by methods 2, 4,
and 5. These determinations show an increase of 30 per cent. in
the entire xylem area, an increase in xylem wall thickness of 13 per ‘
cent., and the same increase in the thickness of the walls of the hard
bast fibers. A count of the hard bast fibers showed no increase in
the number of these elements.
Experiment 11. Ricinus communis, field culture—The method
in this experiment was the same as in experiment 2. The tension fas-
tening was placed just below the second pair of leaves. The control
plants were not supported. The experiment began July 20 and
ended August 1. A tension of 300%™ at the beginning was gradually
raised to 2350%™ two days before the experiment ended.
TABLE VII.—Ricinus communis
< lz i
e ez s 2 @ Fo n
: E 4 o BS§ = oe
Height to Chie at Diam. just § cay eX 2s
2d pair of wh ah above 1st 2 on 2. | Bay
. base in : bo oes ove
leaves in panel pair of leaves| & Zeck 5 2 =e E
cm. in mm. tas 6 - og | ks
PE | Bae) Be | z
a IR * :
July | Aug. | July | Aug. | July | Aug. | Aug. | Aug. | Aug. gens
20 I 20 I 20 ‘ I I ee 038
16.25 Ey aS a § 8.18)}12.18)10.66 13.01/43 86/10. 24 21S
16.4 |19.6 | 8.44/11.41| 9.95|12.56|41.22/10.4 25-99|2-929
eee See prs teat
|
The average results, given in table VII, show 43.86** as the aver
age breaking strength for the experimental plants and 41.22%8 for
the controls, or 6.4 per cent. The increase is slightly greater than
the final weight which was attached to the experimental plants. 1°
average xylem wall thickness and total xylem area, as determined by
methods 2 and 3, show an increase respectively of o. 1# and 4 per cent.
or ee ee See > er oe
a:
“ . ae ey Nea a hata >
Se Oy Mee RPT ee pe Emer NT ome ey et tie ten RE Pt RR ae a ee ee ee
1909] BORDNER—INFLUENCE OF TRACTION ON STEMS 269
The bast fibers were not well defined; many of them only very slightly
thickened. It was therefore impossible to make an accurate count
of their number.
Experiment 12.. Rubus occidentalis, field culture—On June 25,
1907, ten young stems were selected which in general appearance were
equally vigorous. Tension fastenings were placed on five of these
approximately 35°™ from the ground. The controls were left free.
A weight of 2.25** at the beginning was increased to 4.5‘¢ on July
6, and to o** 24 days later. The experiment ended September 3o.
The decrease in height in the experimental plants was very marked.
Growth in diameter was also less. The total bast and xylem areas
were determined by method 3, giving an average increase in bast of
13.6 percent. over the controls, buta decrease in xylem of 30 percent.
This decrease may be partly attributed to the reduced growth in diam-
eter of the experimental plants.
Experiment 13. Vicia Faba, greenhouse culture.—The experi-
mental plants were put under tension on October 24, 1907, the fasten-
ing being placed just below the fifth node. Since Vicia Faba grows
very rapidly, it was thought possible that it might respond to a stronger
tension than that applied to stems of other species of like cross-section
andage. A weight of 450%, therefore, was applied at the beginning,
increased to goo®™ two days later, and to 13008" on November 6.
Since illumination is greatly reduced at this time of the year and growth
is comparatively slow, this large weight caused the stem to elongate
More rapidly than the control. This was accompanied by diminished
gtowth in diameter. The control plants were left free, and since
Vicia Faba retains its orthotropic position with great difficulty, these
grew larger in diameter and less in height. When the experiment
ended on November 9, the breaking strength of the experimental
Plants was less than the breaking strength of the controls.
Experiment 14. Vicia Faba, greenhouse culture—The results
of experiment 1 3 gave cause for this experiment, in which an effort
was made to eliminate or at least minimize the effect of those factors
which may have obscured the response to tension in the last eApen
ment, if such a response did occur. For this reason, the experment
Was carried on during the season of the year when illumination was
much stronger and hence the chances for growth much better, all other
270 BOTANICAL GAZETTE [OCTOBER
factors affecting growth remaining unchanged. Smaller weights also
were used on the experimental plants, and the control plants were sup-
ported by small weights, barely sufficient to counterbalance the weight
of plant, attached as the larger weights were to the experimental plants,
the cords running over pulleys. The experimental and control plants
were now growing under exactly the same conditions, except that the
former were subject to tension of 2008™ at the beginning, increased
to 450°™ on March 19, and to 700o%™ on March 23, and finally to g50*™
on March 30. The experiment ended April 6.
TABLE VIII.—Vicia Faba
ne) =
“il = 3
BE6)¢ | 2 28
E ye cas Height to 4th | Diam. just | Diam. just |22.E) : §
grb ses ot re node in above rst below 4th ee se 2 E m 5 |
Pp cm. leafin mm. | node in mm. | £ AS fxm] oe =a
awo| a= So | &¢g
Swell) as | °2 | &¢
7 e Sh v.a ot Es
(a = A *
| |
Mar. | Apr. | Mar. | Apr. | Mar. | Apr. | Mar. | Apr. | Apr. | Apr Apr. | Apr
Exp. 14 | 6 14 145°) 36 I 6 6 6 6
1 Gare 21.3 69.8 ES 012023 5.0: 8 40! 4.82)-6:33 8.8 |24.91 1630.3/|22 75
Control
Av. :....|22.4 |66. |15.3 {18:0 | 6.01/ 8.40) 4.80 6.39 9-3 |20-59 141Q.4|2T.00
Pe RE i | j | eens Se
The results are given in table VIII. The breaking strength shows
an increase of 4.35** or 21 per cent. for the experimental plants over
the controls. The number of hard bast fibers, determined by method
5, and the total xylem area by method 3, show an increase in the former
of 14.8 per cent., and in the latter of 8.3 per cent.
TAB LE IX.—Lupinus albus ees
Height to Diam. oesitooe Ne: - Xylem
No. of plant Height in cm. | cotviedons between gr area in
| sagas and cotyledons pone
|
Pls Aeaii Meier SE | rae les |
: | '
Mar, Mar. ! Mar. | Mar Mar. Mar. Mar. | Mar
Exp. 2 Be 2 to) 2 30 3° a
AV... Sarees 4-74 g.02 | 3.54 5.06 3.9% 2.91 839-4 | 9
Control ; |
7 | ‘ .800
AV. cad ccd arent ie | 3-55} 3-97 | 3-70} 2-97 155 |
ae
Experiment 15. Lupinus albus, greenhouse culture.—This expe™
ment began March 2 and ended March 30, the experimental plants
Igog] BORDNER—INFLUENCE OF TRACTION ON STEMS 271
being subjected to a tension of 250%™ at the beginning, increased to
500%™ seven days later, and to 750%" on March 19. On account
of the shortness of the stems, which made it impossible to fasten
them into the apparatus firmly enough to hold a sufficient weight,
the attempt to determine the breaking strength of these stems
Was unsatisfactory. The reduced diameter, in that part of the stem
below the cotyledons as shown in table IX, was due to a collapse of
the tissue surrounding the stele. The total xylem area and number
of hard bast elements, determined by methods 4 and 5, show an
average increase of the former to be 14 per cent. and of the latter 11
per cent.
Summary
An average of the different determinations made in the foregoing
experiments is given in table X. In all except experiment 9 with
Vinca major and experiment 13 with Vicia Faba, the average break-
ing strength in the 246 tests shows an increase in the experimental
plants over the controls. This must be attributed to a response to
traction along the longitudinal axis of the stem. The negative results
in experiment g show that the older part of the stem, where active
Srowth has ceased, does not respond by increasing its breaking
strength. The lack of response in experiment 13 with Vicia Faba
can be attributed to factors which vitiated the influence of tension.
These conditions are fully explained in experiments 13 and 14.
Experiments g and 13, therefore, may be left out of consideration.
The average area of the cell wall of the hard bast elements shows an
increase in the experimental plants over the controls for Helianthus
dnuus and Sinapis alba. This determination was not made for
the other species investigated. The average number of hard bast
elements shows an increase in the experimental plants over the con-
_ trols in all the species for which this determination was made, except
Vinca major. Phaseolus vulgaris and Rubus occidentalis also show
an increase of total bast area in the experimental plants over the con-
trols. The average thickness of the hard bast fibers in Vinca major
as found to be greater for the experimental stems. .
In the total xylem area determinations, the only decrease was 1n
Sinapis alba and Rubus occidentalis, in both of which, however, there
- 242
BOTANICAL GAZETTE
[OCTOBER
was an increase in hard bast. The other species all responded to
tension by increasing their xylem area. The average thickness of
TABLE X.—SUMMARY
No. of
experiment
Avi Aver- | Aver- |Average| ,._. |Average
— i age | age thick. ick thick- | 175 of
Name of plant ing ead pny beni of hard Pans ee
eogth) bast | bast bast | bast Pos xylem
n kg. fibers | fibers | area |cell walls cell walls
lelianthus es Ls BEE a 7 § mn eae ae 6.70 5
lianthus annuus | 3 Watine asl’ Gan of sk 4570 5
felianthus annuus /16, SS eres eaectiaaits sate pore ee
elianthus annuus |13., Tia wo paiae| Eee arcae Peeerand eboney (Ae Macnee poe
elianthus annuus 69 SONOS 7% SEC es ee ee
elianthus $106,520). si: Epi fetes peters Rene 57 Sy
napis a By F7Ol Se. TR O36) sol. aves 9-39] 3-
napis alb au 5-330 MEE OE aia ee. 10.51| 2.993} 20
haseolus Vitpatis 16, 9get S|. BRUogiss COORG oer
haseolus vulgaris Oe, | ee ae ase NOSE oO 5 -42].-+++-
Phaseolus vulgaris (eect e) Waseremte | ge Plane oly oo ae adie La eee
Phaseolus vulgaris ce’ fo. (aeeperee | Reagent) Wein enti be onee abe cos
Phaseolus S16. 3361. S top Co Beenie Seren wey Maar CS Ei
Phaseolus vulgaris y As on pee ea es Ops Pees epee oeese bere
Vinca major is or | ome ane Ee Soren eee Se nee
2 ajor gS IR cate eran eee eed Mame etry Daren ats cn ec 9c
Vinca major* Lh, 2 CS Sinea ee paatieeraes peta! paren ome
Vinca major* i; Rag Rn tess Sy npems Cerne P<
Vinca major Bogaat os 1276|:.... 7-42 |-2777| 5-77
Vinca major GOO7Gh 5 os 7] see 6.56 |.2141| 5-09
Ricinus communis Ags HOOPS e hele ligl pe eee a ed 2759] | eres
cinus communis |41.220|......|.....|.....|...... 5-99}- +--+ +}
ubus occidentalis |. 0.1... 1... SOs 210
Rubus occidentalis | .....|......|..... cee Bae £i9O9) ss os
Vicia Faba* PALOO SS seen] cele 3 | apa si Boccia terme acti aae ee oie
Vicia Faba* BO gt a eb see eee
Vicia Faba 24 OTOL 6s BOBO eee 22.75). +0
Vicia Faba 20 SOON ss 2 PAID) ste 21.00]..--+-
Adenine Wibaa to PAG) iis a eee ts Q127|----+°
Lupinus albus {......|.... i ee ips a ae S000}. ..++:
* See experiments for explanations of negative results.
° . . . . : in
xylem cells walls in Sinapis alba and Vinca major was also greater
the experimental stems than the controls.
%
Conclusion
The results of the foregoing experiments have convinced the sed
conclusively that actively growing stems of the herbaceous plant
investigated and of Vinca major respond to traction along their cat
tudinal axes, by increasing their breaking strength; also “a ee
increased development of bast or of xylem, and in most cases by
Z
q
4
4
=
4
af
4
=
S
N
1909] BORDNER—INFLUENCE OF TRACTION ON STEMS 273
increase of both these mechanical tissues. The experimental evidence
for Rubus occidentalis was too limited to be conclusive. The stems
were already too old and mature when the experiment was started.
The writer is convinced, however, by this experiment with Rubus
occidentalis, that the tension used by WIEDERSHEIM (29) on pendant
woody branches was not sufficient to send a stimulus past the stimulus
threshold.
UNIVERSITY OF MICHIGAN
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ia) ul
(aaa)
am
9
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nt
ral
BOTANICAL GAZETTE [ocTOBER
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- Von Derscuav, M., Der Einfluss von Kontakt und Zug auf “rankende
Blattstiele. Togaguial Dissertation, Leipzig.
1693.
. WIEDERSHEM, W., Ueber den Einfluss der Belastung auf die Ausbildung
von Holz und Bastkorier bei Trauerbiumen. Jahrb. Wiss. Bot. 38:41. 19°3-
- Worcrtzky, Vergleichende Anatomie der Ranken. Flora 69:79- 1887-
THE MODIFIABILITY OF TRANSPIRATION IN
YOUNG SEEDLINGS
JosrEpH Y. BERGEN
(WITH FIVE FIGURES)
The writer has often noticed the fact that young seedlings (e. g.,
of Cucurbita and Phaseolus) grown under bell glasses wilted almost
at once when exposed to the dry air of a furnace-heated or steam-
heated room. Gardeners all know that plants started in cold frames
must be “ hardened” by gradual exposure to the ordinary atmosphere,
brought about by lifting slightly the sashes with which the cold frames
are covered.
It appeared worth while to investigate quantitatively the rate of
transpiration of these tender seedlings, grown in an extremely moist
atmosphere, and the simplest possible case for study seemed to be that
of annuals, for these cannot be supposed to have inherited a tend-
€ncy to develop extreme adaptations to an abnormally moist atmos-
Phere during part of the brief lifetime of the individual plant. Seed-
lings of the following species were grown in well-watered earth, some
under glass cases with air-tight joints, and others in the free air of
a furnace-heated room.
Cucumis sativus Oxalis corniculata
Ipomoea purpurea Phaseolus vulgaris
Lupinus albus Salvia splendens
Mirabilis Jalapa Sinapis alba
Nicotiana “Sanderae”
The temperature was on the average about the same for the covered
and the uncovered plants; the former, of course, received a trifle less
light than the latter. The moisture of the atmosphere about the
leaves naturally differed greatly. Those in glass cases were in a
_‘Rearly or often quite saturated atmosphere. Those in the free air
“4 the room were in an atmosphere of which the relative humidity
during the winter months ranged from 16 to 32 per cent., averaging
less than 25 percent. This is drier than the average summer atmos-
Phere of an oasis in the Sahara. Some plants were also grown In 4 —
“73) [Botanical Gazette, vol. 48
276 BOTANICAL GAZETTE [OCTOBER
greenhouse, where the relative humidity was usually not far from
60 per cent.'
In general the plants grown in nearly saturated air and in dry air
or in that of moderate humidity presented considerable contrasts in
their development.? Those from moist air were taller, more slender,
longer-leaved, less hairy (if the plant were naturally pubescent), with
od
én j : as 3 >hotograpnet
Fic. 1.—Ipomoea plants, moist-air form and dry-air form. X4- Photograt
by Rospert CAMERON.
. a < 3 Re 2a VES.
thinner, lighter-colored, more pliable, and more translucent a6:
ee ‘ selop-
In many cases the moist-air plants showed an accelerated deve af
. ; ‘ : sicet 1€
ment, producing more leaves in a given time and flowering et ‘
A : : eee! ae tiv
than those in drier air. Most of the exact measurements 0! rela ;
nr * > . y 7 Vi yar
‘ The writer’s thanks are due to Professor GEORGE L. GOODALE of Har
University for the use of space in the greenhouses of the university.
2 See WIESNER, J., Forminderungen von Pflanzen bei Cultur im
Raume und im Dunkeln. Ber. Deutsch. Bot. Gesells. 9:46-531- 1891.
absolut feuchte?
1909] BERGEN—TRANSPIRATION IN YOUNG SEEDLINGS 277
development were made on plants of Phaseolus. In different lots of
these, the moist-air individuals were 15 to 40 per cent. taller than those
grown in drier air. The leaves of the former were sometimes as
much as 80 per cent. longer than those of the latter, the difference
being largely in the petioles. On the other hand, the diameter of the
first internode above the cotyledons was (in plants grown in the green-
house) 30 per cent. greater for those outside the moist glass cases.
For house-grown plants the leaf thickness was 25 to 40 per cent.
greater in the dry-air plants, and for those grown in the greenhouse
Fic. 2. Sinapis, entire stem and leaves, moist-air form. X4.—Fic. 3. Sinapis,
upper half of stem and leaves, dry-air form. X
it was 2 5 per cent. greater than for those under glass cases. The
Most notable differences in growth of dry-air and moist-air individuals
Were shown by Ipomoea, in which the moist-air specimens were
‘wining freely, when dry-air specimens of the same age had relatively
short internodes and showed no tendency to twine (fig. 1). Mirabilis
Plants in nearly saturated air, by the time the second pair of true
leaves had spread apart, were three times as tall as those grown in
house air and much more slender. Sinapis, on the other hand,
appears depauperate when grown in nearly saturated air, as shown
% gs. 2, 3. The leaves of Sinapis, and of Cucumis also, in very
Moist air often show the less indented margin referred to by WIESNER.*
3 Wiesner, J., Biologie der Pflanzen 65, 66. Wien. 1902.
278 BOTANICAL GAZETTE [OCTOBER
The relative translucency of moist-air leaves and dry-air leaves was
approximately measured in the case of Nicotiana and of Ipomoea
y blue-printing them with various terms of exposure to sunlight,
until an equal degree of blueness was obtained-for the portions of
paper covered by each kind of leaves.¢ The moist-air leaves of
Ipomoea were found to be 3.5 times as translucent as the others, and
those of Nicotiana 3 times. In the latter plant many of the first
leaves grown in moist air stand nearly vertical, while those of the dry-
air plants form approximate rosettes. This vertical growth of the
moist-air leaves is exactly the reverse of the epinasty of the leaves of
Sempervivum tectorum and Ovxalis floribunda noted by WIESNER.’
The differences in form and size between Nicotiana leaves and
Ipomoea leaves grown under moist and under dry conditions are
shown in jigs. 4, 5.
The histology of the leaves studied did not differ nearly as much
as it often does in sun plants and shade plants of the same species.
In house-grown individuals of Phaseolus, leaves developed in dry
air exceeded in thickness those in the glass cases by 25 to 33 per cent.,
the upper epidermis of the former was about 25 per cent. thicker, and
the palisade layer was a little thicker. On the other hand, moist-air
leaves of Sinapis were found to be a little thicker, and of Ipomoea
sometimes 25 percent. thicker, than leaves of these genera grown in
dry air. As might have been expected, less notable differences were
found between leaves grown in air nearly saturated with moisture and
those grown in the moderately moist air of the greenhouse.
The behavior of moist-air leaves and dry-air leaves, on being
deprived of a water supply and exposed to air at a temperature of
about 21° C. and 25 per cent. relative humidity, differs greatly. Ifa
shoot of each kind is cut and exposed to such air, in many cases —
(Brassica, Cucumis, Ipomoea, Oxalis, Phaseolus) wilting begins in
from 0.5 to 2 minutes. Even if the shoots are cut under water and —
kept with the cut end always submerged, wilting is prompt and con-
tinuous. Shoots of Phaseolus were cut and laid in sunshine, in ait |
of humidity probably below 25 per cent., at a temperature of 23°3 C.
:
One shoot was from the saturated air of the glass case, the other from 4
4 This of course only measures translucency with reference to those rays which
affect the blue-print paper
chs
q
1909] | BERGEN—TRANSPIRATION IN YOUNG SEEDLINGS 279
dry house air. Bits of the lower epidermis were peeled from the
under surface of each kind of leaf at about 2-minute intervals and
instantly placed in absolute alcohol to fix the stomata.’ The opera-
tion was repeated on another day with fresh sets of leaves. It was
found that in less than six minutes the stomata of the dry-air leaves
were most of them closed to less than half their initial width, while
; Fic. 4. Nicotiana leaves; A, moist-air form; B, dry-air form. X4.—Fic. 5.
Pomoea leaves; A, moist-air form; B, dry-air form. X4
those of the moist-air leaves were but little affected. In about 15
minutes most of the stomata of the dry-air leaves were tightly closed,
While most of those of the moist-air leaves still remained open.
_ Apparently the speedy wilting of the moist-air leaves is due to two
causes, the insufficient closure of the stomata and the relatively high
Permeability of the general surface of the epidermis to moisture.
Wag vto™ F. E., The physiology ‘of stomata. Publ. 82, Carnegie Institution of
ashington, 1908,
280 BOTANICAL GAZETTE [OCTOBER
A curious kind of quick adaptation to dry conditions may some-
times be noted. Young leaves of Ipomoea, grown in nearly saturated
air, were found to wilt in air of less than 30 per cent. relative humidity
in about two minutes, though the stem was cut off under water and
kept immersed in water. After being left for some hours in a satu-
rated atmosphere until the wilting had entirely disappeared, the
shoots were left, with the cut ends in water, in an atmosphere of less
than 30 per cent. relative humidity for 48 hours without showing any
signs of wilting. More than go per cent. of the stomata were at this
time found to be perfectly closed.
The relative transpiration rate in diffuse light of moist-air and
dry-air leaves of nearly all the kinds of seedlings grown was carefully
determined. Attempts to make use of very slender (and therefore
quick-reading) burettes as potometers were not successful. It was
found too difficult to attach the soft and readily crushed stems of @
young seedlings to the burettes in such a way as to be sure to obviate
leakage. All losses by transpiration were therefore estimated by
weighing the shoots and the tubes of water which contained them on a
balance sensitive to 5™6. The relative humidity of the air in which
the transpiration took place was measured by the sling psychrometer
(sometimes twice) during each experiment. As might have been
expected, the inequality of transpiration was found to be greatest in
the case of fully developed leaves, half-grown ones showing less,
though notable, differences. The values given below are for the
ratio M/D, in which M is the transpiration of the moist-air leaf and
D the transpiration of the dry-air leaf. ;
In discussing the results above given, it should be noted that a
considerable range of values in the ratios obtained is almost unavoid-
able. In the first place we have to reckon with the great variability
of transpiration in individuals of the same species grown under
identical conditions. F. Hapertanpr® found in the case of rye
plants that the transpiration per day varied (in round numbers) from
2 to 7™ per square decimeter for different individuals. Also, if the
transpiration were allowed to take place in a nearly saturated atmos-
phere (to prevent sudden wilting), the leaves would be under condi-
6 HaBERLANnr, F., Wissensch.-prakt. Untersuchungen auf dem Gebiete des
Pflanzenbaues 2:146. Wien. 1877.
Ree Oa ye ee
Biny:
pe re 3
P ¢ I) ok penne r y eed i ae
weL ¥ ‘ yi PEER eal OE RET enon ” b ay
Pe we ee ae ee ee ee Ee eee ee ee
mee eg fy ae te Oe eee ie eens eee WEE Sey ee ay eee Pes) eee tN PN eMC Tred TT ER ND Re. Lae ene ee ee mere Peer
So ee ey eee
t9g09] BERGEN—TRANSPIRATION IN YOUNG SEEDLINGS 281
tions abnormal for the kinds of plants studied. If the atmosphere
were to be made very dry, the leaves grown in very damp air would
wilt inside of five minutes or less and die in a comparatively short
time. In some cases it was found best to determine the transpiration
of readily wilted leaves for a period of fifteen minutes and compare
TRANSPIRATION RATIOS
Kind of leaf Rel. humid. during trans. period | Ratio M/D
Phaseolus 25 { 2.2
Phaseolus 63 2.5
Phaseolus.........- 64 3:2
LAPINUSS. 32 ok 26 4.0
DDI OUS . 25:5: o as , about 43 8.2
GUDINUS, fess ee ae | about 38 To.0
LUpinus.ccss5 eee | variable, probably over 40 1.9*
Mirabilis. iH 36 3-9
Mirabilis... 2. 603 29 4.8
Tpomoea.)....4,. 080. 26 / 7-4
SAW Sos seca 34 6.6
OAiVide aA ee Fin 8.9
SINE PIS ss gc ks 28 3-5
Snewmis. ge 24 3g
Cueumia:s. so is20s 34 | 9-3
Mieptiaia... co.cc about 50 oe
* Young leaves, only half grown or less.
t The moist-air leaves transpired on May 42 in air of 28 per cent. relative humidity, and the dry-air
ones on May 13 in air of 34 per cent, relative humidity.
this with the (calculated) fifteen-minute loss of the dry-air leaf of the
same species, allowed to transpire for one or two hours. Oxalis
corniculata from saturated air became wholly wilted inside of one
minute, on being removed from the glass case, so its transpiration
tatio could not be determined. It would be interesting to compare the
Telative transpiration of the two kinds of leaves in extremely dry
air minute by minute, but weighings on a balance delicate enough
for this purpose could not be made with sufficient rapidity.
The conditions as regards relative humidity were intentionally
Varied a good deal, in order to show whether the transpiration ratios
follow closely the changes in humidity. It is evident that in Phaseolus
and Lupinus they do not.
hile no experiments were made with a view of measuring the
absolute rates of transpiration of the plants studied, all under the
same conditions of temperature and humidity, it may be worth
282 BOTANICAL GAZETTE [ocToBER 4
while to give the values obtained for moist-air leaves of some of
them.
‘TRANSPIRATION OF I00 SQ. CM. OF LEAF IN AN HOUR
Plant ite ces go i a Pager ti
Cucumis? 5 20 34 1485
Lupinus....... "21.67 43 3596
Nicotiana..... QE.tt 50 or less Ig50
Phaseolus. .... 26.11 2 1647
napis 22.22 28 2135
Summarizing the results obtained from the transpiration measure-
ments,’ it may be said that:
_1. As a result of being grown in a highly humid atmosphere, all
the plants studied acquire a much greater than normal capacity for
transpiration in a moderately dry atmosphere.
2. Different families and different genera of the same family
vary greatly in their capacity to acquire by such culture a tendency
to extremely rapid transpiration.
3. The transpiration ratios, for the same species, become notably
greater as the leaf becomes fully developed.
4. The transpiration ratios are not necessarily greater when the 7
relative humidity of the air, during the period when transpiration 15
measured, is very low than when it has a medium value.
CAMBRIDGE, Mass.
7 Not nearly all of these results have been tabulated in the preceding pages-
A REMARKABLE AMANITA?
GEORGE F. ATKINSON
(WITH EIGHT FIGURES)
During the autumn of 1908 I received from Mrs. VircrIniA Gar-
_ LAND Batten, of Brookdale, Santa Cruz Co., Cal., a number of
_ Specimens of an Amanita which presents several remarkable pecul-
larities in its development and environic relations. | For several years
_ Mrs. BALLEN has observed this Amanita and has made a careful field
_ Study of the more salient features of its development. This account
_ of the fungus is based on fresh specimens and photographs which she
_has sent me, and upon her notes and descriptions, which show a
temarkable appreciation on her part of the important morphological
_ Characters, as well as of important features of development.
This plant grows in the mountain forests of California. It is
_ among the largest species of Amanita, the cap being 10 to 22°™ in
_ diameter, one of the larger ones, according to Mrs. BALLEN, being
: Sufficient for a meal. It thus rivals in size the royal Amanita of
E Europe, which it surpasses in robustness, though not possessing its
; Nich orange-yellow color, and not attaining the height of the larger
_ Specimens of that species. It is interesting to note that the stocky
character of this plant with its short stem is probably an expression
: of One of its environic and seasonal relations. It occurs in the high
4 Sierras and in the Coast Range. Probably the entire summer season
: 1S needed for the growth and extension of the mycelium in the forest
_ Mold, so that the huge fruit bodies are developed in late autumn and
: early Spring. While we have as yet no information bearing on the
€ of origin of the fundament of the fruit bodies, it is likely that
: all of them are formed during the summer and late autumn, and that
_ the second crop, which appears early in the spring, is composed of
Plants which have lived through the winter in a partially developed
| ondition. The autumn crop ceases about the last of December,
_ While the spring crop begins about the middle of March.
* Contribution from the Department of Botany, Cornell University, No. 135.
283] [Botanical Gazette, vol. 48
284 BOTANICAL GAZETTE {OCTOBER
In the high Sierras, where it is colder, the plant is well protected
from frost injury, since it rarely if ever appears above the carpet of
leaves covering the forest floor. Here it grows about the pines and
firs. It has here almost become a subterranean fungus, a remarkable
Fic. 1.—Partly expanded plant, showing calyptra of volva closely adhering to the
pileus, the veil with the floccose remnants of the fundamental tissue between it and the
stem, and the limb of the volva at base of stem.
thing for an Amanita. Thus it is difficult to find, the only evidence
of its presence being the mounds of conifer needles which the hidden
plants raise above them, Uncovering these and removing the plant
there is a large cone-shaped hole in the soil made by the pressure of
the very thick stem and cap. They are often found in bitter cold
-NOSNIAXLV
‘Ps GAN ‘reed
S
iS
>
S
™
VIINVAYV
iG. -Three plants showing circumscissile dehiscence of the volva; the plant at the left with the delicate veil torn and (in front)
the inner S tolice of the volva.
286 BOTANICAL GAZETTE [OCTOBER
weather, when the ground is covered with snow, but are so well
protected by the covering of needles and snow that they are perfectly
fresh and uninjured, while a few hours’ exposure to the air results in
their being frozen. In the Coast Range they are smaller and not so
; : nd sup-
Fic. 3.—Partly expanded plant, showing veil attached at apex of BS isa
: : = a
ported in a divergent position by the mass of loose cottony remnants of the fum
tissue lying between the veil and stem.
bright-colored, and are found around the madrojfas, chestnuts, =
pines, and spruces. Mrs. BALLEN has never found them around the
redwoods. The spring crop is also paler than the autumn crop-
In the mountains about Brookdale, Santa Cruz Co., they appeat
above the ground.
1909] ATKINSON—A REMARKABLE AMANITA 287
The pileus is a maize-yellow in its bright-colored forms and varies
toa pale straw color or Naples yellow (R.) in the vernal forms. The
gills are at first white and later become tinged with the same color.
The stem and inner veil or annulus are also tinged with pale straw
é 3. 4.—Section of plant showing pendent veil and loose cottony fundamental
ss & . ‘
Sue between it and the stem.
Color. The volva is thick, stout, and white, though in age it becomes
More or less soiled and tinged with yellowish brown. The pileus is
broadly rounded in the young plants, becoming broadly convex to
Plane, or in old plants the margin may become elevated, thus giving
the pileus ;
Pileus a depressed appearance.
288 BOTANICAL GAZETTE foCTOBER
Very little of the surface of the pileus is visible, since all except a
narrow marginal portion is covered with the calyptra of the volva,
which forms a thick, white, tough skin or covering, closely and
tightly fitting the cuticle of the pileus. In cutting through the calyptra
and pileus the line of junction can be seen, and in fresh plants this line
of division is brought out distinctly because of the pale-yellow cuticle
of the pileus. This calyptra, covering the larger part of the pileus like
lar of the volva,
IG. 5.—The stem separating from the volva; note inner col
striate margin of the pileus, and very distinct thick calyptra.
a closely fitting cap, is often unbroken; but in large, well- expanded
plants, it is often cracked into irregular large areas, as in fig: 9; 6, show-
ing the pileus between.
The inner veil is very thin and fragile, and disappears soon after
the opening of the plant. When the plant is expanded the annulus is
attached to the extreme upper end of the stem at the point of junction
of the gills and stem, for the gills are adnexed, as in some other
of Amanita, and the stem is not readily separable from the
The plant is very fleshy, is often attacked by larvae, and readily ye
so that transport of mature or nearly mature specimens is dificult.
species
pileus-
1909] ATKINSON—A REMARKABLE AMANITA 289
In the button stage they sometimes carry and keep well for several
days.
The inner veil is slightly connected with the edges of the gills and
thus the expansion of the pileus produces a tension which tears the
veil from the surface of the stem, with which it is also connected by
G. 6.—Surface of pileus, showing calyptra torn into large patches, which remain
1
IG,
tightly adherent to the pileus.
“emnants of the fundamental tissue. This tissue, lying between the
Veil and the stem, is very loose and floccose, so that it is torn into
a delicate cottony mass, which often supports the veil in a divergent
Position as it hangs from the apex of the stem (figs. 3, 4). The veil
itself is very delicate in texture, and Mrs. BALLEN says that it “seems
'o melt away” soon after the expansion of the plant. This indicates
that it is not well differentiated from the fundamental tissue. In
290 BOTANICAL GAZETTE [ocroBER
buttons which were shipped to me, and which opened in transit or
after reaching here, this inner veil did not separate from the stem, but
remained as fundamental tissue clothing the stem (jig. 7, where the
outline of the cortex of the stem is shown within).
_ The stem is stout and comparatively short. The volva is circum-
scissile, but the lower half, which remains attached to the base of the
stem, is large, with an ample, stout, free limb forming a large sac-like
structure resembling that of the Amanitas with apical dehiscence,
though the edge is more even. Within the basal portion of the volva
and surrounding the stem there is often present a narrow collar or
secondary sheath, the origin and nature of which, to my knowledge,
have never been carefully described in any Amanita, for it is usually
overlooked.
This inner collar or secondary sheath I have studied carefully in
Amanita caesarea of Europe, while studying the higher fungi in the
Jura Mountains of France, from specimens collected at Besangon and
Arbois, in September, 1905. PLOWRIGHT? has called attention to 4
similar inner collar in specimens of Amanitopsis spadicea, and pro-
posed to employ it in separating this species from A. livida, the two
being usually brought together under this name, but he offered no-
suggestion as to its significance or origin. I have observed it and
studied its origin also in Amanitopsis livida Richon & Roze and do
not think that much specific importance can be attached to it, since
it varies so in strength in different specimens and is often so obscure
when it remains, as it sometimes does, closely applied against the
base of the stem. Great credit, however, is due to Mrs. BALLEN for
having made such careful observations on the presence and nature
of this interesting structure in the California Amanita, the more S°
since there is no published description of such a structure, and her
observations, though later than mine on Amanita caesarea and
Amanitopsis livida, were entirely independent of them, and made
before she had called my attention to the existence of this species.
Longitudinal sections of the young plants when in the more
advanced “egg” stage show all of the principal parts well formed.
The pileus and stem when cut or bruised often turn a pale straw
> Trans. Brit. Mycol. Soc. 1897-8:40. See ATKINSON, Mushrooms, edible,
poisonous, etc. 75. st ed. 1900, Ithaca. 2d ed. rgor, Ithaca, and 1993; New York.
. 7.—Plants ee after transit from California to Ithaca, N. Y., showing dehiscence; middle plant in section, showin
very iy the thic of the calyptra; inner veil remaining attached to the stem and continuous below with the tissue that
forms the collar on ie toate of the volva, indicating that all of the tissue which lies between the cae and the gills is hindus
issue.
—_
[606r
ATAVHIYVNAY V—-NOSNIXNLV
VLINVAV
2Q2 - BOTANICAL GAZETTE {OCTOBER
yellow on exposure of the cut surface to the air. In such sections of
young plants therefore the pileus is clearly marked off from the sur-
rounding volva, and the wall of the stem is likewise marked off
distinctly from the surrounding fundamental tissue. The gills are
also well outlined. The slightly convex outline of their edge does not
permit them to lie against the surface of the stem, and their lower or
outer ends curve away from it in the young stage. This space is filled
with fundamental tissue, and as the plant expands it is left free from
Fic. 8.—Photomicrograph of spores with Zeiss ocular 18, objective 37; object
370™m from plate-holder.
the stem and gills, but attached to the inner side of the base of the
volva as a collar around the stem. When the plants become quite
mature or old, there are tissue changes at the base of the stem inside
of this collar which permits the stem to be very easily separated from
the volva. By this time the free limb of the volva has recurved more of
less, leaving the volva in the shape of a saucer with a recurved edge,
and an inner collar. At this stage, if one takes hold of the cap to lift
the plant, the stem is freed from the volva cup, leaving this saucer”
shaped structure in the ground. Fig. 5 is from a photograph of this
stage, showing this saucer-like structure of the volva with its inne
collar, and the freed stem at one side. In dry weather this separation
of the stem from the volva does not take place.
I have proposed the name Amanita calyptroderma for this plant,
ee Le ee
Fo) ee, ea ne Pte Teak ee et em eee
“Erato
Tra
TE) Oe SE ee
;
x
;
3 E
3
E
1909] ATKINSON—A REMARKABLE AMANITA . 293
because the calyptra of the volva fits like a skin over the center of the
pileus. Although a technical description has been published else-
where,’ it may be well to add a diagnosis here.
AMANITA CALYPTRODERMA Atkinson & Ballen.s—Plants 1o-15°™
high, pileus 10-22°™ broad, stem 2-4°™ stout. Pileus maize-yellow
to pale chrome-yellow, gills white, then pale maize to cream color,
annulus and stem pale maize to cream color, volva white. Pileus
stout, fleshy, convex to expanded and even depressed in age, margin
striate, slightly viscid when moist, larger part of pileus covered with
the tough thick calyptra of the volva which fits closely like a skin,
the margin free, while in age in the larger plants the calyptra of the
volva is cracked into rather large areas by the expansion of the pileus.
Gills broad, adnexed, edge more or less floccose. Basidia 4-spored.
Spores oval to elliptical, smooth, coarsely granular, 8-12 7-8 Bb.
Annulus very thin, membranaceous, superior, hanging from the
extreme apex of the stem, soon disappearing. Stem hollow, with
loose cottony threads, even in the smaller plants, tapering upward in
the larger ones, or smaller at base, surface floccose. Volva white,
thick, circumscissile, in dehiscence the upper part remaining on the
center of the pileus, lower portion of limb very prominent, 2-4°™
long, sometimes appressed on the stem, but usually distinctly
divergent and in age recurved, often with a distinct inner collar near
the base, in age the stem often separating from the volva, leaving the
latter as a saucer-shaped structure with its inner collar in the ground.—
Mountain forests, California, in late autumn and early spring, Mrs.
Virginia Garland Ballen. WHerb., Cornell Univ., no. 22620.
* Science N. S. 293944. 1909. |
Closely related to Amanita calyptrata Peck, Bull. Torr. Bot. Club 27:14.
*909, but differs in color and other characters.
UNDESCRIBED PLANTS FROM GUATEMALA AND OTHER
CENTRAL AMERICAN REPUBLICS. XXXII"
: JouHn DoNNELL SMITH
Pithecolobium (§SaAMANEA Benth.; Ser. Carnosae Benth.) cate-
natum Donn. Sm.—Folia ampla, pinnis unijugis, foliolis 3-5-Juss
obovato-oblongis vel -ellipticis obtuse cuspidatis basi acutis, stipulis
uti glandulae interpetiolulares obsoletis. Pedunculi axillares longis-
simi. Legumen lineare longissimum moniliforme polyspermum
bivalve, loculamentis atque seminibus ellipsoideis.
Frutex, ramis petiolis pedunculis ferrugineo-puberulis. Petiolus communis
4-8™ longus, pinnarum erecto-patentium rhachi 12—22°™ longa, foliolis chartaceis
praeter costam utrinque puberulam glabris subtus pallidioribus in eodem jugo
inaequalibus per ae deorsum decrescentibus, supremis r1-16°™ longis 5-7.5™
latis, infimis 3-9°™ longis 2-4.5°™ latis, nervis lateralibus utrinque 6-7, venulis
subtus minutissime reticulatis, petiolulis 2-3™™ longis. Pedunculi 8-18°™ longi,
floribus sessilibus. Legumina crasse coriacea rubiginoso-subvelutina addito
stipite 12-22™™ longo 24-26°™ longa epulposa demum dehiscentia inter semina
arcte constricta, loculamentis 15-17™™ longis g-11™™ crassis leviter compressis,
isthmo infimo interdum 12-14™™ longo, ceteris 2-4™™ longis, seminibus 11-1?
circiter 13-15™™ longis 8-10™™ latis atrocoloribus, hilo subapicali—Florum
tantum reliquiae visae. Ad P. sophorocarpum Benth. legumine semine embryone
accedens foliis longe distat.
_ In silvis profundis ad praedium Swerre vocatum, Llanuras de Santa Clara,
Comarca de Limén, Costa Rica, alt. 300", Febr. 1896, John Donnell Smith, n. 6479
ex Pl. Guat. etc. quas ed. Donn. Sm
Appunia guatemalensis Donn. Sm.—Glabra. Stipulae breviter
vaginantes bicuspidatae. Folia subsessilia magna elliptico- Vv vel obo-
vato-oblonga utrinque acuminata. Capitulum singulum pauci- et
laxi-florum, bracteis ovario paulo longioribus glandulis 1-3 cuspidatis.
Calyx campanulatus truncatus basi glanduligerus quam corolla octies
brevior.
Frutex. Stipulae coriaceae acuminato-triangulares 3™™ longae, cuspidipws
minutis. Folia subcoriacea utraque pagina nitentia 13-16°™ longa me edio vé
petiolis 2-3™™ longis. Pedunculi axillares 3.5-4°™ longi, one ae
7-floro absque corollis 5-6™™ longo atque lato, oils acuminato-o
‘ Continued from Bot. GAZETTE 47: 262. 1909. [204
Botanical Gazette, vol. 48] :
1909] SMITH—PLANTS FROM CENTRAL AMERICA 295
longis, floribus heterogoneis (brevistylis solum visis). Calycis 2™™ longi in sicco
nigricantis tubus hemisphaericus limbum aequans, glandulis linearibus paucis.
Corolla 16™™ longa ad 2™™ supra basin staminigera. Antherae subsessiles 3™™
longae. Discus 0.5™™ altus. Ovarium 1™™ longum, stylo uti stigma pyramidale
™™ longo. Bacca ignota.
In silva prope pagam maritimam Livingston, Depart. Livingston, Guate-
mala, Jun. 1906, H. von Tuerckheim (n. IL. 1230).
Palicourea (§Crocornyrsus Griseb.; Ser. Croceae Muell. Arg.)
leucantha Donn. Sm.—Glabra. Stipulae vaginam amplam laxam
truncatam subaequantes. Folia elliptico-oblonga utrinque acuminata.
Thyrsus .elongatus, axibus angulosis, bracteis bracteolisque majus-
culis. Calycis limbus alte partitus ovario 2-4-plo longior. Corolla
alba ad } altitudinis paleaceo-annuligera.
lat toe lineari-lanceolatae re etia
se
Internodia obtuse tetragona. Stipul j
longae. Folia subtus minute puberula 14-17°™ longa medio 4-7“ lata, petiolis
lineari-lanceolatis 4-9™™ longis, cymis dichotomis, pedicellis 3-9™™ longis.
Computatis lobis 2™™ longis 15-16™™ longa margine virescens paleis niveis
annuligera ad 3 altitudinis staminigera. Antherae medio e 2™m Jon
filamenta aequantes apice exsertae. Discus hemisphericus 1.5™™ altus. Ovarium —
cylindricum y-1.smm longum atque crassum biloculare, stylo 7™™ longo, lobis
T.5™™ longis. Bacca deficit.—P. mexicanae Benth. affinis.
In silva montana ad viam inter Coban et Tactic, Depart. Alta Verapaz,
Guatemala, alt. 1800™, Mart. 1903, H. von Tuerckheim, n. 8400 ex Pl. Guat. etc.
quas ed. Donn. Sm.—In monte prope Coban, Depart. Alta Verapaz, Guatemala,
alt. r650™, Jun. 1908, H. von Tuerckheim (n. II. 2282).
Parathesis microcalyx Donn. Sm.—Folia lanceolato-obovata
Cuspidato-acuminata in petiolum attenuata integra supra glabra
Subtus glabrescentia. Panicula terminalis foliis superata. Calyx
brevis, lobis deltoideis tubum aequantibus. Corolla staminibus bis
longior. Ovarium apice pubescens totum post anthesin calyce
aequilongo arcte cinctum depresso-globosum. :
Folia recentiora subtus cum ramulis petiolis "panicula{floribus ferrugineo-
Pubescentia, provectiora glabra erga lucem inspecta punctulis et lineis pellucida,
Saltem Superiora (solum visa) g-12.5°™ longa 3.5-4™ lata, petiolis I-t. 5°™ longis.
296 BOTANICAL GAZETTE [OCTOBER
longae acutae lineato-maculatae intus glabrae. Antherae ovatae 1™™ longae
area dorsali atra deltoidea epunctatae filamentis bis longiores. Ovarium corolla
jam delapsa 1™™ longum paulo latius quam longius, stylo 2.5™™ longo. Fructus
age ae —P. serrulatae Mez proxima.
n fruticetis secus rivulum ad fundum La Colombiana dictum, Llanuras de
as Clara, Comarca de Limén, Costa Rica, alt. 200™, Jun. 1899, H. Piitier,
n..7591 ex Pl. Guat. etc. quas ed. Donn. Sm. (n. 13410 herb. nat. Cost.).
Gonolobus (§Monostemma K. Schum.) leianthus Donn. Sm.—
Folia longe petiolata sparsim pilosiuscula ovato-oblonga acuminata
sinu profundo rotundato cordata. Pedunculi biflori et pedicelli
graciles, floribus glabris inter maximos. Segmenta corollina lan-
ceolato-oblonga parum reticulata calycinis ovatis sesquilongiora.
Corona tenuiter annularis subintegra gynostegio brevissimo adnata.
Frutex volubilis, ramis petiolisque patenter pilosis vel glabrescentibus, pedun-
culis pedicellisque glabris. Folia g-12°™ longa 3.5-5°™ lata supra paene glabra
subtus setulis minimis aspersa, petiolis 6-8°™ longis. Pedunculi 2-4™ longi,
pedicellis inaequalibus 3-5°™ longis, floribus 5°™-diametralibus. Calycis seg-
menta paene sejuncta late imbricata herbacea 13™™ longa 5™™ lata acuminata.
Corollae alte fidae segmenta 2°™ longa 7-9™™ lata acute elongata carnulosa in
sicco badia erga lucem inspecta reticulata. Corona callis contiguis minutis
multidenticulata mediantibus carinis tenuibus gynostegio connexa annulo mem-
branaceo pubescente corollae adnato comitata. Gynostegium vix 1™™° altum
6™™-diametrale——G. macrantho Kunze proximus.
Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350™, Oct. 1901, H. vam
Tuerckheim, n. 8243 ex Pl. Guat. etc. quas. ed. Donn. Sm.
Trichostelma oblongifolium Donn. Sm.—Folia Janceolato-ob-
longa cuspidato-acuminata basi acuta vel obtusiuscula. Cymae
sessiles. Segmenta corollina calycinis lanceolatis bis longiora ovato-
lanceolata cymbiformia apice cucullato recurva. Corona exterior
parce longeque ciliata, interior breviter cupularis vix lobata. Gyno-
stegium breve appendicula paulo longius.
Suffruticosum volubile patenter pilosum. Folia discoloria utrinque
bulbosis aspersa 8-11°™ longa medio 3-5°™ lata, nervis subtus fusco-villosis,
petiolis “1-2 longis. Pedicelli 3-5-fastigiati_1.5-3.5°™ longi, floribus extus
carnulosa to-loba
extus eaccee A sched a gynostegio flinch ube I. ae
longa lobis divaricatis 3™™ lata. Pollinia pendula oblongo-elliptica eeere
paulo longiora. Folliculi desunt—A specie hactenus unica, T- ciliato
(Fimbristemma calycosa Donn. Sm. ), foliis atque floribus optime distinctum.
1909] SMITH—PLANTS FROM CENTRAL AMERICA 207
In fruticetis ad Panzal, Depart. Baja Verapaz, Guatemala, alt. rooo™, Apr.
1907, H. von Tuerckheim (n. Il. 1747).
Solanum (§ LeEropENDRA Dun.) Rovirosanum Donn. Sm.—
Folia gemina parum inaequimagna elliptica vel obovato-elliptica
bis longiora quam latiora in Sectione maxima sursum in angulum
acutum vel obtusum desinentia in petiolum brevem plus minus
attenuata, nervis lateralibus utrinsecus 6—7 ad axillas nudis. Pedicelli,
cymoso-fasciculati numerosi graciles, floriferi cernui, fructiferi erecti.
Frutex omnibus in partibus glaber. Folia pergamentacea concoloria nitida
19-30°™ longa 9-14.5°™ lata, altero circiter quinta parte minore, petiolis 8-18"™
longis. Pedunculi ro-24™™ longi nonnunquam furcati, pedicellis floriferis 6™™
longis, fructiferis 11™™ longis. Calyx obpyramidalis 2.5™™ longus, lobis tubo
bis brevioribus rotundatis calloso-apiculatis. Corollae tubus 1™™ longus, laciniae
lanceolatae 6—7™™ longae. Antherae conniventes oblongae 3™™ longae 1™™ latae
nigricantes ad apicem luteum poris anticis amplis ellipticis dehiscentes, filamentis
complanatis 1™™ longis. Ovarium ovoideum, stylo 5™™ longo. Bacca nondum
satis matura calyce accrescente cincta globosa 7™™-diametralis nigra.
Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 350™, Aug. 1904, H. von
Tuerckheim, n. 8716 ex Pl. Guat. etc. quas ed. Donn. Sm.; Jul. 1907, H. von
Tuerckheim (n. II, 1888).—Eandem plantam collegit José N. Rovirosa in Mexico
ad Mayito, Estado de Tabasco, Jul. 1889, et sub numero 544 distribuit.
Athenaea cernua Donn. Sm—Glandulari-puberula. Folia gla-
brescentia plerumque solitaria ovata cuspidato-acuminata basi
Cuneata vel rotundata. Pedunculi axillares vel dichotomales solitarii,
flore atque fructu cernuis. Calycis lobi elongato-triangulares sub
anthesi tubo paulo longiores. Corollae limbus campanulatus triente
lobatus, lobi deltoidei. Bacca coccinea.
Herbacea, ramis dichotomis sulcatis et petiolis glandulari-puberulis. Folia
membranacea punctulata nervis et margine puberula 4-7.5°™ longa 2.5-4™ lata
Integra interdum gemina, altero consimili triente minore, petiolis 1.5-3°™ longis.
Pedunculi 2.5-3.2°™ longi subglabri, floribus 7"™ longis. Calyx glandulari-
Puberulus 3-5™™ longus, lobis sub anthesi 2™™ longis. Corollae luteae tubus
cylindricus ym longus, limbus abrupte ampliatus basi staminigerus, lobi 2-2.5™™
longi ciliolati. Antherae ovales 2™™ longae 1™™ Jatae filamentis subaequilongae.
Ovarium ovoideum 1.5™m™ longum, stylo 3.5™™ longo. Bacca globosa Ae
diametralis calycis aucti lobis 3.5™™ longis obvelata, seminibus fusci bi latis
In silva ad praedium Sasis, Depart. Alta Verapaz, Guatemala, alt. goo™, Maj.
1908, H. von Tuerckheim (n. II. 2245).
Brachistus ceratocalycius Donn. Sm.—Glabrescens. Folia lan-
Ceolata e medio utrinque acuteque angustata plerumque solitaria,
298 BOTANICAL GAZETTE {OCTOBER
floralia gemina homomorpha subaequimagna. Pedunculi singuli vel
2-4-ni. Calyx medio infra marginem truncatam scariosam tuber-
culis 10 appendiculatus. Corolla infundibularis paulo ultra medium
lobata. Antherae ellipticae filamentis altero tanto longiores.
Frutex, ramulis novellis furfuraceis. Folia 7-10°™ longa 1.7-2.5°™ lata
supra primum puberula mox utrinque glabra, nervis lateralibus ideas 5-6,
venis transversis parallelis remotis parum manifestis, petiolis 5-12™™ longis et
" pedunculis calycibusque puberulis. Pedunculi 15-31™™ longi erecti. Calyx
hemisphaericus 3.5™™ altus, margine scariosa 1™™ lata, tuberculis squarrosis
subconicis. Corolla violacea (cl. repertor in scheda), 16-17™™ longa in alabastro
griseo-pubescens, lobis lanceolatis ad apicem versus et ad margines pubescentibus.
Antherae 5™™ longae 2.5™™ latae apiculatae margine exteriore dehiscentes.
Ovarium ovoideum 2.5™™ longum in stylum aequilongum attenuatum. Bacca
ignota.
In silva montana prope Coban, Depart. Alta Verapaz, Guatemala, alt. 1600”,
Jan. 1908, H. von Tuerckheim (n. II. 2060).
Ruellia (§ DipreracantHus Baill.) pygmaea Donn. Sm.—
Folia approximata minima oblongo-ovata acuminata basi acuta
integra supra paleaceo-pilosa subtus nervis ferrugineo-strigillosa.
Flores ad axillas oppositas foliorum superiorum subsessiles, bracteis
linearibus calyce paulo longioribus corolla 5-6-plo_ brevioribus.
Capsula puberula 4-sperma infra medium contracta et compressa.
Caules € rhizomate longe repente foliis abortivis munito passim ascendentes
6-8" longi simplices et petioli ferrugineo-strigillosi. Folia internodiis longiora
superne imbricantia 13-25™™ longa 7~-10™™ Jata supra pilis longis articulatis
aspersa utrinque lineolata, nervis lateralibus utrinsecus 4, petiolis 2-3"™ longis.
Bracteae 4-5™™ longae paleaceo-pilosae. Calycis puberuli tubus 1.5™™ altus,
segmenta linearia 2-2.5™™ longa. Corolla extus puberula 24™™ longa supra
basin cylindricam 8"™ Jongam sensim et aequaliter ampliata faucibus 5™™ lata,
lobis late rotundatis 3™™ longis. Stamina bene inclusa, antheris 2”™ lene
Capsula oblongo-ellipsoidea 8-9™™ longa acuminata sulcata, parte solida A
longa, seminibus orbiculatis 2™™-diametralibus margine cano-pubescentibus. ai
R. humijusae Hemsl. proxima. :
Hacoc prope Cubilquitz, Depart. Alta Verapaz, Guatemala, alt. 600™, Maj.
1904, H. von Tuerckheim, n. 8725 ex Pl. Guat. etc. quas ed. Donn. Sm.
Ruellia (§ Puysrevert1a Lindau; Ser. Eglandulosae Lindau)
guatemalensis Donn. Sm.—Folia glabra ovata vel lanceolato-ovata
acuminata basi angustata vel rotundata margine undulata. Flores
subsessiles 1-4-ni axillares vel in cymis axillaribus terminales ¢t
dichotomales, cymis folia superantibus, axibus elongatis, bracteis
1909] SMITH—PLANTS FROM CENTRAL AMERICA 209
- longissimis. Corolla usque ad medium cylindrica tum ventricoso-
infundibularis.
Frutex, ramis obtuse tetragonis minute cystolithigeris, angulis et nodis
puberulis. Folia chartacea utrinque praesertim supra lineolata 9.5-10.5°™
longa 3.5-4°™ lata, vel superiora magis ovata 5°™ longa 2.5°™ lata, nervis latera-
libus utrinsecus 4~5, petiolis puberulis canalicularibus amplexicaulibus 10-18™™
longis. Cymae nondum satis evolutae addito pedunculo 5-8°™ longo 10-14°%™
longae puberulae parce furcatae pauciflorae, axibus erecto-patentibus 1.5-3.5°™ |
longis, bracteis linearibus 2— 3™™ longis, bracteolis lanceolatis 2™™ longis. Calycis
tubus 2™™ longus, segmenta linearia 7™ longa. Corollae tubus totus 3°™
longus, pars cylindrica 1.5™™-diametralis, lobi obovato-orbiculares 8™™ longi
emarginati. Stamina inclusa, filamentis per paria leviter connatis, majoribus 8™”
longis minores dimidio superantibus, antheris 2.5"™ longis. Discus 0.5™™
altus. Ovarium glabrum oblongo-lineare 5" longum 12-ovulatum triente
contractum et vacuum, stylo puberulo 31™™ longo. Capsula matura ignota.
Ad praedium Concepcién vocatum, Depart. Escuintla, Guatemala, alt. 400™,
Apr. 1890, John Donnell Smith, n. 2115 ex Pl. Guat. etc. quas ed. Donn. Sm.
(Sub Ruellia. sp. olim distributa.)—Ad ripas fluminis Ocosito prope pagum
Caballo Blanco, Depart. Retalhuleo, Guatemala, alt. 80", Apr. 1892, John
Donnell Smith, n. 2692 ex Pl. Guat. etc. quas ed. Donn. Sm.
Pseuderanthemum verapazense Donn. Sm.—Folia lanceolato-
oblonga in acumen obtusum angustata basi acuta praeter costam
subtus viscidulo-puberulam glabra. Spica terminalis simplex vel
Tamis binis aucta bracteis foliaceis lineari-oblongis fulta, bracteolis
triangulari-linearibus calyce bis brevioribus, floribus singulis subses-
silibus.
Caules e rhizomate longe repente hinc illinc erecti subsimplices 1o~25°™
longi teretes bifariam viscido-pubescentes. Folia lineolata 5-7°" longa 18-20"™
lata, petiolis pubescentibus 3-4"™ longis. Spica puberula 3-7°™ longa, ramis
2-3™ longis, bracteis 12™™ longis 3™™ latis, bracteolis 1.57™ longis et floribus
Puberulis. Pedicellus o.5™™ longus. Calycis segmenta linearia acute attenuata
3-3-5™™ longa. Corollae laete azureae (cl. repertor in schedula), tubus 16™™
longus triente superiore paulo ampliatus ceterum vix o.5™™-diametralis, lobi
ongis. Ovarium puberulum 4-ovulatum, stylo 16™™ longo bilobo.
apsula ignota.—P. hispidulo Rad\k. proximum.
In silvis montanis ad Yaxcabnal, Cubilquitz, Depart. Alta Verapaz, Guate-
mala, alt. 320™, Mart. 1902, H. von Tuerckheim, n. 8258 ex Pi. Guat. etc. quas
ed. Donn. Sim.
Dicliptera (SSpHENOsTEGIA Nees) podocephala Donn. Sm.—
Folia breviter petiolata ovato-lanceolata subsensim acuminata basi
300 BOTANICAL GAZETTE [OCTOBER
angustata. Pedunculi axillares 1-3-ni elongati monocephali, captulis
lineari-bracteatis, involucris 3-8 uni- vel bi-floris, phyllis involucrali-
bus apice rotundato cuspidatis, bracteolis 4 calyce bis longioribus.
Corolla paulo exserta.
Fruticulosa 1-1.5-metralis diffusa, ramis obtuse sex-angularibus uti petioli
pedunculi involucra lineolatis et puberulis. Folia membranacea glabra cystolithis
striolata 8.5—-12.5°™ longa 3.5-4.5°™ lata, petiolis 13~17™™ longis. Capitula
omnia pedunculata, pedunculis 1-9. 5°™ longis in axillis superioribus singulis, in
inferioribus binis vel ternis inaequalibus. Bracteae capitula semicircularia
fulcientes binae 4~7™™ longae, involucris plerumque 5, exterioribus decrescentibus,
phyllis obovatis basi cuneatis pergameneis nervosis reticulatis per paria inaequi-.
magnis, majore 11-14™™ longo 8-9”™ lato in statu sicco colorato, altero quarta
parte minore viridi, bracteolis lanceolato-linearibus 8™™ longis, flore altero
abortivo vel deficiente. Calycis laciniae setaceae cum bracteolis puberulae.
Corolla 14™™ longa, limbo pubescente. Antherarum loculi inaequialte affixi.
Stylus 12™™ longus. Capsula pubescens ovoidea 5™™ longa apiculata disperma,
seminibus puberulis 2.5™™-diametralibus.
In pratis humedis ad praedium Atirro vocatum, Prov. Cartago, Costa Rica,
alt. 600", Apr. 1896, John Donnell Smith, n. 6685 ex Pl. Guat. etc. quas ed.
Donn. Sm.
Justicia (§ DIANTHERA Lindau) Tuerkheimiana Donn. Sm.—
Pilosa eglandulosa. Folia oblongo-ovata apice obtusiuscula basi
cuneata sparse paleaceo-pilosa. Spica terminalis pedunculata folia
superiora subaequans, bracteis laxe imbricatis lanceolato-ellipticis.
Calycis segmenta acuta. Corollae tubus tenuissimus.
Herba procumbens diffusa ad genicula radicans 23-30 longa, ramis obtuse
tetragonis et petiolis et pedunculo patenter pilosis, glandulis obsoletis. Folia
ejusdem paris parum inaequalia 23-38™™ longa 12-19™™ lata lineolata, nervis
lateralibus utrinsecus 4-5, petiolis 4-10™™ longis. Pedunculus circiter be
ignota.—J. Schenckianae Lindau arcte a :
Ad fissuras saxorum, Cubilquitz, Depart. Alta Verapaz, Guatemala, alt.
350™, Jun. 1903, H. von Tuerckheim, n. 8726 ex Pl. Guat. etc. quas ed. Donn. Sm.
BaLtimore, Mp.
Tea poe
gies
Dene he
ene eee
va ee
BRIEFER ARTICLES
NEW NORMAL APPLIANCES FOR USE IN PLANT
PHYSIOLOGY. V*.
(WITH TWO FIGURES)
In the preceding articles I have described some ten new pieces of
apparatus designed for educational work in plant physiology; accounts
of three more are given below, while others are to follow. They are called
_ hormal appliances because they are intended to represent the optimum
resultant, the harmonic optimum, as it were, between accuracy of results
and convenience of use, while at the same time they can always be bought
from the stock of a supply company. As in the case of the other pieces
these are to be manufactured and sold by the Bausch & Lomb Optical
Company of Rochester, N. Y¥
X. Space markers
For some purposes, especially in the study of growth, it is necessary
to mark off a structure into regular divisions, either areas as in the case of
young leaves, or lengths as in roots, stems, or petioles. It is not difficult to
improvise appliances for accomplishing these ends, but as yet no tools are
available for effecting them quickly, accurately, and conveniently, while
at the same time always ready for use. This need, I think, the two little
instruments here described will supply.
First, for marking lengthwise, the instrument is a wheel, the rim of
which is a rubber stamp having raised cross-lines 2™™ apart. It revolves
freely but evenly on an axle held in the end of a handle, and when suitably
inked by the method described below, it may be run rapidly over long struc-
tures such as roots, marking them with narrow black cross-lines equally
spaced, precisely as shown at the bottom of jig. I.
econd, for marking areas, the instrument is a disc, likewise @ rubber
stamp, haying raised lines in the form of squares 2™™ on a side. It works
by means of a scissors-frame against a cushion disc covered with soft felt
and provided with a radial slot to admit the petiole of a peltate leaf. When
the marking disc is inked and pressed firmly against a leaf held .on the
Cushion disc, it marks a network of even fine black lines like the sample
shown in jig. r. The marking disc is hinged to its supporting arm ms
* Continued from Bor. GAzETTE 43:279. April 1907.
| [
30r] Botanical Gazette, vol. 48
302 BOTANICAL GAZETTE [ocTOBER
way to permit the disc to settle evenly upon the leaf surface no matter
what the thickness of the leaf.
Both instruments may be inked from an ordinary rubber-stamp pad,
and the black record kind gives good results. Better, however, is a simple
Fic. 1.—Space markers. x }.
pad made from one fold of thin close cotton cloth attached by thread to an
ordinary glass slide, and inked when needed by a mixture of three parts
Higgins’ waterproof India ink and one part glycerin.
XI, Demonstration auxograph
Among the most important of the topics which all teachers desire to
demonstrate in general botanical courses is growth, and this can be shown
to complete satisfaction only through use of a recording instrument. Many
recording auxanometers, or auxographs, have been described, but as yet n°
practical instrument for educational purposes is obtainable by purchase.
The essentials of a good demonstration instrument, aside from easy applica-
bility to its work and durability, are reasonable accuracy, ready portability,
visibility of record from some distance, and clear exhibition of its mechan-
ism and principle. These ends, I believe, are well met in the instrument
here described and illustrated (fig. 2). :
It consists essentially of four parts: support-stand, recording cy linder,
magnifying wheel, and plant-support. The support-stand is of rigid
1909} BRIEFER ARTICLES 303
though thin steel, and is provided with convenient handles, leveling screws,
and suitable holes for the two upright rods. The recording cylinder,
Fic. 2.—Demonstration auxograph. 4.
Supported and guided at the top by a screw pivot, turns once an hour, and
is of such circumference that each millimeter of a millimeter record paper
represents one minute. It is carried by a clock which is supported at such
304 - BOTANICAL GAZETTE [ocropER —
a height that it may be wound and regulated from beneath without disturb-
ing the record. The magnifying wheel, really four concentric wheels
combined, allows three degrees of magnification, two, four, and eight times
the actual growth. It is made of aluminum, moves on a very sensitive axle,
has suitable openings for attachment of threads, and is provided with a
clamp for holding it immovable while adjustment of threads and the like
is being made. The tip of the plant is brought into action with the wheel
by means of a fine thread in the usual way; but in order that this thread
may be kept as short as possible, a plant support, adjustable for height, is
provided on a separate rod, thus permitting the tip of the plant to be kept
close to the magnifying wheel, though, of course, care must be taken to
prevent the danger of shading, and hence of phototropic bendings. This
adjustable support, however, has another very important use which will
be mentioned below. The thread from the large wheel passes over a _
pulley to the pen carrier, which slides on a fine guide wire and has sufficient
weight to turn the wheels in proportion as the growth of the plant permits
the small wheel to turn. The pen is of glass, drawn to a capillary point
and bent so as to rest at right angles to the paper. It is filled with chrono-
graph ink, and, as the plant grows and the cylinder turns, it traces a fine
spiral line down the cylinder, crossing any given vertical line once an hour.
When this pen has reached the bottom of the cylinder, one has only to
put on a new cylinder or record paper, turn the large wheel backward until
the pen is drawn to its top, close the clamp to hold the wheel immovable,
lower the plant support until the, thread from the plant becomes again
taut, loosen the clamp to allow the tensions to adjust themselves, and then
the record is resumed; and this procedure can be repeated until the end of
the experiment without any need for ever touching the threads. This is
the other advantage, above mentioned, of the adjustable plant-suppott.
One should never draw up the pen by lowering the plant support, as there —
is a constant temptation to do, since this brings an unnatural strain upon
the plant tip. All parts of the instrument, even to the arms carrying
magnifying wheel and pulley, are adjustable, so the instrument may be
made to work smoothly under any conditions. While designed primarily
for making records of growth, it can be used for any measurements involy-
ing movement, e. g., the rise of water in a tube.
The weak point of all auxographs lies in the threads, which will alter
length hygroscopically and thus introduce error into the record, despite
any known treatment with wax, oil, rubber, etc. These alterations may be
minimized by treating the threads with wax, and by keeping them as short
as possible, for which reason they should be made only long enough to
1909} BRIEFER ARTICLES 305
allow the turning of. the wheels, with no extra turns around the latter.
The error, of course, is greatest from the thread attached to the plant, since
its alterations of length are magnified in the record. Not only should this
thread be kept short, but I think a glass filament could advantageously be
substituted for all of its length except the loop at the plant and the partial
turn around the wheel. The results of these errors can also be relatively
minimized by using plants of the most rapid and vigorous growth, such as
the flower-stalks of bulbous plants——W. F. Ganone, Smith College,
Northampton, Mass.
CURRENT LITERATURE
BOOK REVIEWS
Anisophylly
A monograph on this subject has been prepared by Ficpor,' privat-docent in
plant physiology in the University of Vienna. It is inspired by WIESNER, the
distinguished physiologist of that university, and is dedicated to him. Naturally
enough it is dominated by his views, and is interspersed with quotations from his
writings. Ficpor has gathered together what is at present known regarding
anisophylly and has presented (critically, he says) the subject from both the
morphological and the physiological point of view. In space, at least, the former
predominates; and it must be confessed that the physiology is too obscure yet to
be very satisfactory.
In the first section (36 pp.) the author defines the term, states the history of
the phenomenon, and describes, as various sorts, incomplete, exorbitant, complete,
lateral, habital, secondary, and false anisophylly. The second section (67 pp.)
describes all the cases of anisophylly observed, in the systematic order from
lycopods to composites, including cases of anisocotyly. The third section (55 pp-)
causation; he intends to enumerate experimental work on all recorded cases,
including new observations of his own. He has overlooked, however, the beauti-
ful demonstration of DorEty? that gravity is the cause of anisocotyly in Cerato-
zomia; nor among the anisophyllous gymnosperms does he mention this and other
cases in cycads.
The general conclusion is that anisophylly, which is very much more general
than is commonly thought, cannot be said to be due in nature directly to the
' Figpor, W., Die Erscheinung der Anisophyllie: eine morphologisch physiol”
gische Studie. 8yo. pp. vilit+175. figs. 23. fls.7. Franz Deuticke: Leipzig un
Wien. 1909.
2 Dorety, HELEN A., The seedling of Ceratozamia. Bot. GAZETTE 46:3°5-
1908.
306
1909] CURRENT LITERATURE 307
meet factors of whose value we are ignorant. That ignorance needs emphasis.
To say—‘‘anisophylly is to be looked upon as a special case of anisomorphy, by
which we understand, with WresNER who proposed this term, that fundamental
property of living substance in consequence of which the different organs (in
our case the foliage leaves) have the power, each according to its position toward
the horizontal or toward the parent axis, to assume different typical forms’”’—
is merely to cloak ignorance with pedantry.—C. R. B.
Desert vegetation
A very fitting celebration of the fifth anniversary of the establishment of the
Desert Laboratory was the publication of a treatise on North American deserts
the number of valuable contributions emanating from Tucson. e contribution
here considered includes some of the matter that made up the body of the first”
Teport on our desert region by CoviLLE and MacDovucat in 1903 (Publication 6),
but the great amount of new material, based on subsequent explorations and on
the investigations at Tucson, made imperative the publication of a general treatise
of this sort. An account is given first of the earlier investigations of the institution
and the development of the department of botanical research, especial attention
being directed to problems of long continuance, such as the study of the revegeta-
tion of the Salton Basin and experiments on acclimatization. Nearly half of the
work is devoted to a general account of the various desert regions of North America,
including the various Mexican deserts, the northern sage-brush deserts, the
Mohave desert and Death Valley, the Sonoran and Colorado deserts. Then
follows a sketch of the geological features of the region about Tucson, by Professor
Og BLAKE, territorial geologist of Arizona; herein is contained an account
of the soils, including the caliche, an interesting calcareous formation arising
through deposition from waters percolating upward. An interesting sketch
is given of the seasonal changes in the aspect of the vegetation about Tucson.
The early winter rains stimulate the development of a number of winter perennials
and annuals. In the spring and early summer the aspect is controlled by more
X€rophytic spinose and succulent forms, notably the cacti. The humid mid-
summer, like the winter, is characterized by a number of forms stimulated to
development by the greater moisture. ‘The treatise closes with a consideration of
‘emperatures of plants in the desert (it being suggested that the great difference
between air and soil temperatures is likely to be of significance), the water relations
of desert plants, soil relations of desert plants, conditions contributory to deserts,
and some general remarks on the formation and extent of deserts and the influ-
“nce of the desert on life. This treatise will be a sine qua non for all ecological
Workers, since it brings together what is known concerning our deserts, taking
*MacDoucat, D, T., Botanical features of North American deserts. Carnegie
Institut :
‘stitution of Washington, Publication 99. 19
308 BOTANICAL GAZETTE [OCTOBER
account of collateral information as well as the researches at the Desert
Laboratory.—HeEnry C. Cow es.
Animal galls
A prodigious amount of work is represented by the two ponderous volumes
of Hovarp, devoted to the galls, produced by animals, which have been found
upon European plants, including those of the Mediterranean basin.* Few
botanists, we imagine, are aware of the extent of what now really ranks as a special
branch of biological science, cecidology, which has its own journal, Marcellia, and
is awakening the interest of both botanists and entomologists.
this monumental work Hovarp describes 6239 zoocecidia, produced by
1466 species of animals, on 2299 species of plants. Of the animal gall-producers
the most important are the Insecta, of the families Curculionidae (Coleoptera),
Cynipidae (Hymenoptera), Cecidomyidae and Muscidae > (Diptera), Aphididae
i i Nema
Rotifera are represented by one species each. Of the plants 68 are cryptogams,
35 gymnosperms, 173 monocotyls, and 2053 dicotyls.
A large number of the galls are illustrated by original figures and some copies, ~
both external and sectional views being given when necessary to show structure.
The part of the plant deformed is indicated; the gall is described tersely, with
compact and inconspicuous bibliographical notations; the specific name of the
There is a full bibliography, arranged alphabetically by authors; an index to
the animals named, preceded by a tabular view of the genera, classified by families
and orders; and an index of the plants by genera and species
It is not often one sees a scientific work involving jaeh multifarious detail
planned so carefully and carried out so consistently and successfully. Herein
the publishers doubtless deserve praise for active cooperation. It would be
difficult to find a flaw in either plan or execution.
Since no extensive studies on the cecidia of this country have been made,
these volumes, the most thorough, comprehensive, and accurate that have yet
appeared in any country, will doubtless serve for many years in the preliminary
work that needs to be done on our own galls. They must certainly be most
useful, and it is to be hoped that with such a guide, more of our younger biologists
will take up the study with vigor.—C. R. B.
a Darwin memorial volume
Among the numerous publications in commemoration of the centenary of
the birth of CHartes Darwsn and of the fiftieth anniversary of the publication of
4 Hovarp, C., Les zoocécidies des plantes d’Europe et du bassin de la —
ranée. 2 vols. 8vo. pp. 1248. figs. 1365. pl. 2. portraits 4. Paris: A. Hermann
Fils. 1909. 45 fr.
D
i
'
1909] CURRENT LITERATURE 309
_ the Origin of species, no one seems more appropriate and satisfactory than the
volume issued by the Cambridge Philosophical Society and the Syndics of the
University Press.s It consists of twenty-eight essays written by those who are
most competent to present the various appropriate topics. The result is to
illustrate the far-reaching influence of Darwrn’s work and also the present atti-
tude of investigators toward Darwinism. Some of the essayists have restricted
themselves to DARWIN’s own work; while others have outlined the progress of
more recent research, which has been the direct outcome of his work. Two
photographs of DARWIN are reproduced, one made in 1854, and the other in 1880;
while a reproduced etching gives a most interesting view of the study at Down.
To review such a collection of essays briefly is impossible, but the subjects and
the authors will indicate the general contents to those interested in evolutionary
octrine. Ten of the twenty-eight essays are of interest to botanists.
The series most appropriately begins with an introductory letter by Sir JoserH
D. Hooker, for forty years the intimate friend and correspondent of Darwin.
The ten essays of botanical interest are as follows: ‘‘Darwin’s predecessors,”
by J. Artur THomson (15 pp.); ‘The selection theory,” by Aucust WEIs-
MANN (48 pp.); ‘‘Variation,” by Huco pE Vries (19 pp-); “Heredity and varia-
tion in modern lights,” by W. BATESON (17 pp.); “The minute structure of cells
in relation to heredity,” by EDUARD STRASBURGER (Io pp.); “The palaeonto-
logical record. II. Plants,’ by D. H. Scorr (23 pp-); “The influence of environ-
ment on the forms of plants,’ by GEORG KLEBS (24 PP); “Geographical dis-
tribution of plants,” by W. T. THISELTON-DYER (21 pp.); “‘Darwin’s work on the
movement of plants,” by Francis DARWIN (16 pp.); “The biology of flowers,”
by K. Gorse (23 pp.) :
All of these essays address themselves primarily to the intelligent public
rather than to investigators, and therefore they are in a sense popular statemen
and not contributions to knowledge. In spite of this, they are very interestin
to investigators, for personal and recent points of view are in evidence throughout,
and the whole group of related topics is brought together in clear and compact
&
form.—J. M
MINOR NOTICES
Recent publications from the National Herbarium.—A. S. HitcHcock (Contr.
U. S. Nat. Herb. 12:183-258. 1909) has issued a “Catalogue of the grasses of
Cuba.” The work is based primarily on material in the herbarium of the Experi-
ment Station at Santiago de las Vegas, Cuba. Sixty-six genera are recorded and
to these are referred 225 species of which ro are indicated as new; one new genus
(Reimarochloa) is proposed. More than one-half (36) of the genera here listed
ee Tepresented by single species. The author gives carefully prepared keys
leading to the genus and species and also cites numerous exsiccatae, thus greatly
s Darwin and modern science. Essays edited by A. C. SEWARD. 8vo. pp. xvii+
59°. Cambridge: The University Press. 1909. $5.00. er
310 BOTANICAL GAZETTE [OCTOBER
enhancing the practical value of the publication.—J. N. Rose (ibid. 259-302) has
published the sixth paper in his “Studies of Mexican and Central American
plants.” About 75 species are described as new, and several transfers have been
made. Three new genera (Pelozia, Pseudolopezia, and Jehlia) of the Onagraceae
are briefly characterized. The text is supplemented by numerous illustrations.—
P. C. STANDLEY (2bid. 303-389. pls. 28-43) publishes an interesting systematic *
treatment of the Allioniaceae, dealing chiefly with those of the United States.
The author recognizes 16 genera, describes about 50 species and some 20 so-called
sub-species as new to science; three of the genera enumerated are new, namely
_ Anulocaulis, Commicarpus, and Hesperonia. Through an apparent oversight
the genus Commicarpus either has been omitted from the key to the genera or
confused with Senkenbergia.—N. L. Brirron and J. N. Rose (ibid. 391, 392.
pls. 44, 45) propose a new genus (Thompsonella) of the Crassulaceae; the genus is
represented by two Mexican species. The type of the genus is Echeveria minuti-
flora Rose.—J. N. Rose (ibid. 393-409. pls. 46-59) describes 10 new species of
flowering plants chiefly from Mexico and the southwest, including also a new
genus (Conzatlia) of the Leguminosae, and makes critical notes on species
previously published.—N. L. Brirron and J. N. Rose (ibid. 413-437. pls. 61-76);
in an article entitled ‘The genus Cereus and its allies in North America,’’ have
recorded 24 genera, of which 15 are designated as new. Of the 131 species
enumerated 12 are described as new, 77 form new combinations, and 19 are of
doubtful generic relationship. The new genera proposed are as follows: A cantho-
cereus, Bergerocactus, Heliocereus, Hylocereus, Lemaireocereus, Leptocereus,
Lophocereus, Nyctocereus, Pachycereus, Peniocereus, Rathbunia, Selenicereus,
Weberocereus, Werckleocereus, and Wilcoxia.—J. N. Rose (ibid. 439, 44°
pls. 77-81) describes and illustrates 5 new species of Crassulaceae from Mexico.—
J. M. Coutrerand J. N. Rose (ibid. 441-451. pls. 82, 83) have issued a “Supple-
ment to the monograph of the North American Umbelliferae” in which the authors
include descriptions of 6 new species; two new genera are also proposed, namely,
Ligusticella and Orumbella.—W. R. Maxon (ibid. 411. pl. 60) describes and
illustrates a new species of Asplenium from China; and (ibid. 13: 1-43. pls. 1-9-
1909) in continuation of a series of articles begun in an earlier volume of this
‘journal has published results of further studies of tropical American ferns. In
this paper, the second of the series, the author describes 16 species of ferns and
2 species of Lycopodium from Mexico and Central America, and also presents
a “Revision of the West Indian species of Polystichum”’ in which 19 species are
recognized, 4 being hitherto undescribed.—J. M. GREENMAN.
A garden book.—A lover of flowers will find pleasure and inspiration in 4
charming book entitled A little Maryland garden by Heten Asué Havys.° She
writes in a most interesting and pleasantly intimate way of her experienc
starting a flower garden, of her successes and failures, and of the great satisfaction
8.
es in
6 Hays, HELEN AsHE, A little Maryland garden. 12 mo. pp.——: PM
New York: G. P. Putnam’s Sons. 1909. $1.
1909] CURRENT LITERATURE 311
one derives from a garden which is klein, aber mein. The book is beautifully
illustrated with eight halftones in color by ZvutmaA Dr L. STEELE, and would be
a pleasing gift book, as well as an excellent reference book for an amateur who
may feel, with the author, that “at least it is better to have tried and failed, than
not even to have made the attempt.’’ The author, however, was evidently success-
ful and shows an intimate knowledge of garden life. The nature sketches are
pleasing, and the whole book is written in a very happy vein, to which its attractive
form is appropriate——Mary H. Frost.
Hymenomycetes of the Chicago region.—The Natural History Survey of
the Chicago Academy of Sciences has begun the publication of a descriptive
catalogue of the higher fungi of the Chicago area. The first part, containing the
Hymenomycetes by Morratt, has just appeared.? It is well printed and the
plates are halftones from excellent photographs. The keys to genera and species
should make determination comparatively simple, but the key to genera would
be far more convenient if the page numbers were inserted. The “Chicago area”
means Cook and Dupage counties, with portions of Will County, Ill., and Lake
County, Ind., including about 1800 square’ miles. From this area 371 species
of Hymenomycetes are reported, representing 79 genera, the distribution by
families being as follows: Agaricaceae, 46 gen., 211 spp.; Polyporaceae, 15 gen.,
78 spp.; Hydnaceae, 5 gen., 25 spp.; Thelephoraceae, 8 gen., 41 spp.; Clavari-
aceae, 2 gen., 12 spp.; Tremellaceae, 3 gen., 4 spp.—J.
Indian woods and their uses.—The Imperial Forest Research Institute of India
has begun the publication of a series of memoirs, the first number of which deals
with Indian woods and their uses.$ It is a bulky quarto volume of nearly 500
Pages, dealing wih 554 species. This is only a fraction of the total number ot
Indian woody species, which is said to be about 5000 and rather more than half of
them trees. The first part contains a list of the purposes for which woods
are employed and the woods used for each, while in the second part these woods
are described. There is an index to English and trade names (9 pp.), and also a
Surprisingly extensive one (202 pp.) to vernacular names.—J. M. C.
The flora of central and southern Congo.—Another fascicle® of this important
taxonomic work has been issued recently under the able editorship of Professor
Eu. De WitpeMAN. The present fascicle contains a list of Mycetes prepared by
the late Professor P. HeENntncs, also a list of fungi by H. and P. Sypow, the
Pteridophyta have been elaborated by Dr. H. Curist and the Embryophyta by
Dr. DE Witpeman. Nearly one hundred new species and several varieties are
ee
7Morratr, W. S., The higher fungi of the Chicago region. Part I. The
Hymenomycetes. Chicago Acad. Sci. Nat. Hist. Surv. Bull. 721-156. pls. I-24. 1909-
8 Troup, R. S., Indian woods and their uses. Indian Forest Memoirs 1: No. 1.
4to. pp. 273 + cexvii. 1909.
9Dr Witpeman, Em., Flore du Bas- et du Moyen-Congo. Ann. Mus. Congo.
Botanique, Sér. V. Tome iii. fasc. 1. pp. 147. pls. 27. Brussels. 1909-
312 BOTANICAL GAZETTE [octoBER —
here published, and the text is supplemented by twenty-seven full-page illustra-
tions.—J. M. GREENMAN.
Handbook of deciduous trees.—The ninth part'® of ScHNEIDER’s Handbook
(the fourth section of the second volume) has followed the preceding one?" with
great promptness. As already noted. it presents descriptions of the species of
angiospermous trees, native or under cultivation in central Europe, and is illus-
trated freely. The present part begins with Tilia and ends with Rhododendron.
—j. M. C. ;
NOTES FOR STUDENTS
Morphology of Tumboa:—Three years ago PEARSON published? the results
of his investigation of Tumboa (Welwitschia) from material obtained in one day’s -
collecting. A second expedition to Damaraland was made possible and material
was collected during January and February of 1907, the results of the investiga
tion of which are now published.73 The additional stages thus secured have
put our knowledge of this most interesting plant upon a fairly substantial basis,
and Pearson is to be thanked for his persistent enthusiasm in securing this
difficult material. An outline of what seem to be the most significant new results
is as follows:
The staminate and ovulate strobili are often produced in great profusion
and their occurrence below the single pair of leaves is frequent. Pollination is
mainly effected by a hemipterous insect (Odontopus), the pollen being received by
a nectar drop on the top of the projecting micropylar tube. The pollen grains
frequently germinate in the micropyle at some distance from the tip of the nucellus,
pollination. The generative cell passes into the tube, where its nucleus divides,
the binucleate cell either remaining undivided or forming two male cells. The
tube nucleus begins to break down before fertilization and eventually disappears.
The most critical and puzzling structure of Tumboa, however, is the embryo
sac. Megaspores and embryo sacs are often present in the pith region of the
axis of the ovulate strobilus, so that the cauline origin of the ovule is clear. A
single megaspore mother cell is organized and a single megaspore functions. The
female gametophyte begins with free nuclear division and no vacuolation, and
successive simultaneous divisions occur until there are approximately 1024 free
and crowded nuclei. Elongation of the sac then occurs, chiefly in its micropylar
+¢ SCHNEIDER, C. K., Illustriertes Handbuch der Laubholzkunde. Neunte Liefer-
— (vierte Lieferung des zweiten Bandes). Imp. 8vo. pp. 367-496. figs. 249-. 328.
ustav Fischer. tg09. M 4.
*« Bor. GAZETTE 472415. 1909.
12 Pearson, H. H. W., Some observations on Welwitschia mirabilis escapee:
Phil. Trans. Roy. Soc. London B 198:26s-304. pls. 18-22. 1906. Review in Bot.
GAZETTE 42:67. 1906.
13 __—, Further observations on Welwitschia. Phil, Trans. Roy. Soc. London
B 200:331~-402. pls. 22-30. 1909.
1909] _ CURRENT LITERATURE 313
fourth, so that the outer nuclei are more widely separated than the rest. These
more scattered nuclei are sexually functional, while the more crowded ones in the
inner three-fourths of the sac give rise to the endosperm. Incomplete wall-
formation occurs, dividing the sac into irregular and multinucleate compartments,
those of the upper fourth usually containing not more than six nuclei, while those
of the lower three-fourths contain twelve or more nuclei. ‘The outer multinucleate
cells develop tubular prolongations (prothallial tubes) into the nucellus, into
which the nuclei and most of the cytoplasm pass. Occasionally these sexual
nuclei fuse within the prothallial tube. In the multinucleate cells of the inner
three-fourths of the sac the nuclei seldom divide, but all fuse, forming uni-
nucleate cells. This endosperm, consisting of uninucleate cells whose nuclei
are formed by the fusion of what the author regards as potential gametes, he calls
a trophophyte, to distinugish it from both gametophyte and sporophyte, and says
that it “differs fundamentally from the prothallus of the lower gymnosperms,” a
statement which will have to be amended in a way that will make the proposed
name seem unnecessary.
When connection is established between the tip of a pollen tube and of a
prothallial tube, “the leading female nucleus enters the generative cell within
which fertilization occurs,” which is certainly a remarkable performance.
n embryo-formation, the fertilized egg elongates to form a proembryonal
tube, toward the tip of which the nucleus moves and divides, when a tip cell is
cut off by an ingrowing wall, just as in Gnetum. The tubular cell of the pro-
embryo continues to elongate, while the tip cell develops the embryo, which
consists of about sixty cells when its tip reaches the endosperm.
The author enters into a somewhat extended discussion of the general bear-
ings of the facts he has uncovered, a discussion which will be considered in another
connection.—J. M. C.
Mechanism of photeolic movements.—LEPESCHKIN, whose investigations of
turgor mechanisms have been already extensive and important, has added a study
of the mechanism concerned in the so-called sleep movements of leaves, which he
be suggested. Long sinceS I proposed for the sleep movements the term photeolic
movements, avoiding thus the false implications of sleep, nyctitropic, and photo-
Rastic.) Without referring to the divergent views of various authors on which his
ae
‘4 LepEscHKin, W. W., Zur Kenntnis des Mechanismus der photonastischen
Variationsbewegungen und der Einwirkung des Beleuchtungswechsels auf die Plas-
mamembran. Beih. Bot. Centralbl. 242308-356- 1909. Preliminary paper: Zur
Kenntnis des Variationsbewegungen. Ber. Deutsch. Bot. Gesells. 26a:724-735- 1908.
x HEALD, F. D., Contribution to the comparative histology of pulvini and the
Tesulting photeolic movements. Bor. GAZETTE 197480. 1894. .
314 BOTANICAL GAZETTE [OCTOBER
conclusions bear, an attempt i le here to state clearly and tersely LEPESCHKIN’S
conception of the various processes concerned in the movements by motor organs.
A change in illumination induces a change in the permeability of the plasma
membranes for solutes; this results in an alteration of the turgor pressure, which
of course alters the volume of the opposed halves of the motor organ, and alters it
in the same fashion, though not at the same rate or to the same extent. Darkening
reduces permeability, and consequently increases the turgor; lighting has the
opposite effect. The result of the inequalities of these changes in turgor is a
curvature of the pulvinus. After this has appeared, diffusion of the solutes begins
toward the convex side, where the concentration is now lowest in consequence of
the absorption of water in this half and its expulsion on the concave side; this
leads to the restoration of the normal concentration of sap and a resultant heighten-
ing of turgor on the convex side, with a corresponding lowering of it on the other,
thus intensifying the curvature. Alteration of permeability by changes of illumina-
tion is not peculiar to motor organs, but occurs also in epidermal cells of Trades-
cantia and in Spirogyra, where it is proportionally as great, but cannot have the
Same consequences.t® Of the two movements ordinarily induced by change in
illumination, the rise or fall of the leaf and the reverse, only the primary movement
is produced as described; the reverse movement is rather of the nature of an after-
effect of the primary curvature. Geotropic curvatures of the motor organs are
explicable on the same principles. The’ physiological dorsiventrality of the
motor organs is due to the normal direction of gravity. Plants which raise their
leaves on darkening, have their photeolic movements intensified by being inverted,
while those that drop their leaves have them reversed by inversion.—C. R. B
Seedling structure of gymnosperms.—The third paper under this title, by
Hive and Frarne,'7 treats of the Ginkgoales and Cycadales, and contains the
usual valuable coordination of scattered results. Under the three heads of
cotyledons, transition region, and root, the following conclusions are reached:
otyledons.—The cotyledons, generally two in number, are hypogeal and
are persistently imbedded in the gametophyte; they are frequently unequal and
there is a marked tendency to form lobes, and in some cases there is a short basal
tube; among Cycadales they are more or less closely fused by their ventral sur-
faces; stomata are generally present, secretory cells and canals are common, and
the vascular bundles are mesarch or exarch in varying degrees; the number of
undles in each cotyledon varies from one to eight, in all cases being greater in the
central region than near the base or tip.
Transition region —The transition phenomena occur rapidly, so that most of
the hypocotyl shows root structure; Ginkgo differs from the observed cycads =
that it has a rotation of the protoxylem of the cotyledonary traces; in Ginkgo
each cotyledonary bundle gives rise to two poles of the root (except in the case of
+6 See also TRONDLE, p. 318.
'7 Hitt, T. G., anp Frame, E. ve, On the seedling structure of gymnosperms.
II. Annals of Botany 23:433-458. pl. 30. 1909.
oe er eee Se Oke
a”
eS Sg ee Ree
ils
r
é
:
2
1909] CURRENT LITERATURE 315
three cotyledons, when the root is triarch); among cycads the cotyledonary
bundles are not of equal value in the production of root structure, and even simi-
larly situated bundles vary in the same species; among the cycads the cotyledonary
bundles fuse with the plumular traces and ultimately form a central cylinder of
variable structure.
Root.—In Ginkgo there may be an addition of protoxylem elements after the
root structure has been organized; in Stangeria the primary root may branch
dichotomously; after the initial root structure has been attained, the number of
poles may be increased at lower levels.
The paper closes with a very useful table showing the variation in the number
of bundles in the base of the cotyledons of the fourteen species discussed, and also
the relation of this number to the number of poles in the root structure.—J. M. C
Adaptation in fossil plants.—In his presidential address'* at the anniversary
meeting (May 24) of the Linnean Society, Scorr took occasion to outline the
evidence for adaptation from fossil plants, which naturally dealt chiefly with the
anatomical structures of those ancient vascular plants which he has done so much
to elucidate. No one is more competent to state the facts in reference to ancient
plants, but the conclusions do not seem to be irresistible. In substance they are
as follows: (1) at all known stages in the history of plants there has been a
thoroughly efficient degree of adaptation to the conditions existing at each period;
(2) the characters of plants always having been as highly adaptive as they are now,
natural selection appears to afford the only key to evolution which we possess at
present; (3) the paleontological record reveals only a relatively short section of the
whole evolution of plants, during which there has not been any very marked
advance in organization, except in cases where the conditions have become more
complex, as illustrated by the floral adaptations of angiosperms; (4) the simple
forms of the present flora are reduced rather than primitive, but such reduction
may have set in often at a relatively early stage of evolution, and is therefore
consistent with a considerable degree of antiquity in the reduced forms.
These broad statements, quite apart from their application to certain views of
adaptation, contain much wholesome truth for those who imagine that the pale-
ontological record, as we know it, represents a continuous succession of “‘higher
and higher” plants, for it is becoming increasingly evident that very highly
organized plants existed at the very beginning of our record.—J. M. C.
Morphology of Penaeaceae._STEPHENS published a preliminary account*® of
his studies among the Penaeaceae which was noticed in this journal,*° There has
| how appeared the full account with illustrations,2? so that the morphological
ities
‘8 Scort, D. H., Presidential address before Linn. Soc., 1909- pp. 15-
‘9 STEPHENS, E. L., A preliminary note on the embryo sac of certain Penaeaceae.
Annals of Botany 22:329. 1908.
0 Bor. Sects 45:365- 1908.
s, E. L., The = sac and embryo of certain Penaeaceae. Annals
4 Siaas 2 23: ae ‘pls. 25, 26. 1909.
316 BOTANICAL GAZETTE [ocTOBER
features of this small shrubby group, restricted to the southwestern region of Cape
Colony, are fairly before us. Three of the five genera were investigated (Sarco-
colla, Penaea, and Brachysiphon), suitable material of the other two (Endonema
and Glischrocolla) not being available. _
{he morphological characters of the three genera examined are the same,
so that one account can serve for all: The megaspore mother cell produces four
nuclei, usually tetrahedrally arranged, and these migrate to the periphery of the
mbryo sac, where each gives rise to a group of four nuclei. Three of the nuclei
of each group are organized into cells which resemble an egg-apparatus, while
the four remaining free nuclei fuse in the center of the sac to form the primary
endosperm nucleus, which after fertilization forms a parietal layer of nuclei, walls
appearing much later. The embryo has no suspensor, appearing first as a spher- —
ical mass of cells, which elongates as the tissues are differentiated and the growing
points are organized.
This seems clearly an illustration of the formation of an embryo sac by the
cooperation of four megaspores, in this case the product of each megaspore
remaining remarkably distinct.—J. M. C.
Embryo sac of Pandanus.—A preliminary note?? under this title has already
been referred to in this journal.?3 The fuller account, with plates, has now been
published.2+ Pandanus has long been regarded as a promising primitive mono-
cotyledon, and its investigation is most timely. The general results are as follows:
the archesporial cell (presumably solitary) cuts off a parietal cell which gives rise
to several layers of cells separating the epidermis from the megaspore mother cell;
the mother cell divides transversely into two daughter cells, the inner one of
which directly produces the embryo sac, while the outer one divides anticlinally;
¢ first division within the sac (the second reduction division) results in two polar
nuclei; the micropylar nucleus divides, and there is no division of the daughter
nuclei, nor is there usually any differentiation into egg and synergid; the antipodal
nucleus gives rise to twelve nuclei, whether by simultaneous division or not was
not determined; in the most advanced stages secured no nuclear fusion was
observed, all fourteen nuclei remaining quite separate.
The author still maintains that the embryo sac of Pandanus is a more ancient
type than the ordinary eight-nucleate sac of angiosperms, and that it represents @
new type, “‘with its nearest analogue in Peperomia.”? It remains to investigate the
fertilization stages of this interesting embryo sac, to determine whether the four-
teen-nucleate condition really is the fertilization stage.—J. M. C.
22 CAMPBELL, D. H., The embryo sac of Pandanus. Preliminary note. Annals
of Botany 22:330. 1908.
23 Bot. GAZETTE 45:364. 1908.
*4 CAMPBELL, D. H., The embryo sac of Pandanus. Bull. Torr. Bot. Club
36: 205-220. pls. 16, 17. 1909.
1909] CURRENT LITERATURE 317
The new flora of Krakatau.—Under this title CaAmpBrtt?5 has published an
interesting account of a visit to the island of Krakatau, which was “efficiently
sterilized” in August 1883, the hot ashes and pumice completely covering the island
to an average depth of 30™. The nearest land is an island rokm distant, on which
the vegetation was largely destroyed; while Java and Sumatra are 35 and 45km
distant. TReruB visited the island in 1886 and 1897, and it was examined again
in 1905 and 1906. By 1886, three years after the catastrophe, a considerable
number of plants had been established, the ferns predominating in species (11)
ment of higher vegetation, the blackish slimy films of species of Oscillatoria coating
the surface of the ashes. In 1897, while there were almost no trees, most of the
island was covered by vegetation, 62 species of vascular plants being recorded
(12 pteridophytes, 50 seed plants), and the ferns stil) predominating in the number
of individuals. In the present flora 137 species have been recorded, representing
all the principal groups; the ferns are no longer predominant, and the —
vegetation is rapidly encroaching toward the center of the island. There
remarkable paucity of bryophytes, only two mosses and one Anthoceros having
been recorded.—J. M. C.
Mechanism of anthers.—ScHNEIDER, having investigated the tulip carefully,
objects*® to the conclusions of STEINBRINCK that the rupture of anthers is due to
the cohesion of the diminishing water with Gees in 2 te cel ae In we fisen
he would distinguish the mechanics of t!
valves, and of their subsequent rolling and unrolling. In Tulipa he finds the frst
Tupture due to the pressure of the growing pollen mass—an explanation already
more than a century old. He does not enlighten us as to the remaining processes;
Possibly be are treated in an earlier paper which we have not seen.”7
replies at some length,’ in the usual lively polemic
style of our Teutonic friends. Though talipes were out of bloom before
SCHNEIDER’s article came to his attention, his preserved material even furnishes
some arguments, which are further supported by an examination of the behavior
of a large number of plants of other genera. The only one in which STEINBRINCK
is willing to admit that anything but cohesion mechanism plays a part, even in the
first opening of the valves, is the rye. In this anther “another strong tissue tension
Must cooperate, because the broad cleft remains open when one throws the anther
: *S CamMPBeLL, D. H., The new flora of Krakatau. Amer. Nat. 43:449-460.
wg
*° ScuNeweR, J. M., Zur ersten und zweiten Hauptfrage der Antherenmechanik.
Ber, ersten Bot. Gesells. 27: 196-201. 1909
» Der Oeffnungsmechanismus ae Tulipanthere. Altstatten, 1908.
augur Di Dissectutons. )
D TEINBRINCK, C., Ueber den ersten Oceana ane bei Antheren. Ber.
ay Bot. Gesells, 2°73 300-312. figs. 7. 1909.
318 BOTANICAL GAZETTE [OCTOBER
at once into water.” ‘The first rupture in this case is an explosive one, which
scatters some of the pollen, and cannot be due to the cause assigned by SCHNEIDER.
R. B.
Mesostrobus, a new genus of Carboniferous lycopods.—WaTSON”? has
described the strobilus of a new lycopod from the Lower Coal Measures of
Lancashire. It resembles Lepidostrobus, but the sporangium is only attached
to the distal half of the horizontal portion of the sporophyll, and the somewhat
larger ligule is set in a deep pit. A characteristic point of view is illustrated by
the following quotation: ‘“Lepidostrobus would be derived from a cone having
sporophylls of this type” (Bothrodendron mundum, etc.) “on the adoption of an ~
arboreal habit by the heterosporous lycopods, because radial elongation of the
Sporangium is the most economical way of increasing the number of spores pro-
duced, a necessity for a large tree. If this elongation takes place in the part of the
sporophyll between the axis and the insertion of the sporangium, we arrive at a
condition much like that of Spencerites, and from that condition we can pass
through Mesostrobus to Lepidostrobus.”—J. M. C
Heating of leaves.—It has been known that the evolution of heat may be
demonstrated in living plants by using seedlings and flowers, but leaves have
not been considered favorable material for this experiment. MoriscH has now
shown3° that in many cases 3-5*s of leaves, placed in a basket and packed in
“excelsior,”? show a rise in temperature amounting to 20-45° C. within 12-24
ours. The leaves are usually killed thereby, and after a fall a second rise of
than the first. The first evolution of heat he ascribes to the respiration of the
leaves, while the second is due to the rapid development of microorganisms.
The experiment is simple and worthy a place in the laboratory practice—C. R. B.
Osmotic pressure and permeability.—TRONDLE records another example of
what has been observed by others, namely, change in the permeability of the
protoplast according to the conditions of lighting and temperature. His Lge
liminary reports™ concerns the leaves of Tilia cordata and Buxus sempervirens
rotundtjolia; in the former both palisade and spongy parenchyma, in the latter
only the palisade being investigated. He reports also the high values of 20-26A
for the osmotic pressure as determined by plasmolysis. It is to be remembered
that plasmolytic studies, such as these, in many of which NaCl was used, are of
20 Watson, D. M. S., On Mesostrobus, a new genus of lycopodiaceous cones footy
the Lower Coal Measures, with a note on the systematic position of Spencerites-
Annals of Botany 23:379-3098. pl. 27. 19009.
3° Mouiscu, H., Ueber hochgradige Selbsterwirmung lebender Laubblatter.
Bot. Zeit. 66 : 211-233. 1908. ;
3: TRONDLE, A., Permeabilititsiinderung und osmotischer Druck in den assiml-
lierender Zellen des Laubblittes. Ber. Deutsch. Bot. Gesells. 27:71-78. 1909-
RS ee ae RENE EOE MENS eb eT eS fae TEM eee eee oem es ery
1909] CURRENT LITERATURE 319
questionable validity in the light of OsteRHovtT’s researches in this line.3?—
Anatomy of the ovule of Myrica.—Miss KersHAw:% has investigated the
ovule of Myrica Gale, and has discovered that in all of the morphological features
itis an ordinary angiosperm, with its solitary megaspore mother cell, linear tetrad,
eight-nucleate embryo sac, and porogamy. The following anatomical features,
Owever, are worthy of mention: the nucellus is not only completely free from
the single integument but is also distinctly stalked within it; vascular strands
(eight or nine in number) traverse the integument, without branching, almost to
the apex of the ovule. These two features of the ovule are usually regarded as
primitive, belonging to the ancient gymnosperms rather than to angiosperms.—
oom. C, .
Phototropism of roots.—LINSBAUER and VOUK, after overcoming many
experimental difficulties, have found3+ that the roots of Raphanus sativus and
Sinapis alba, which have been credited with being only negatively phototropic,
Teact positively or negatively according to the intensity of the light. Roots of the
ormer in moist air turn toward light of about 8 candles, while in water they are
much less sensitive, no very certain curvatures being obtained until the light was
increased to 400 c.p. Sinapis in water, on the contrary, gave the best positive
response at o.2 c.p., and decided negative curvatures at 0.64 ¢.p. These results
Support the M@LLER-OLTMANNS theory of phototropism.—C. R. B.
Dispersal of seeds by ants.—Werss%5 has concluded that the gorse (Ulex) and
the broom (Sarothamnus) should be included among myrmecochorous plants,
along with Chelidonium, Viola, etc. He finds that the seeds have a brightly
colored caruncle containing oily food material and resembling in structure and
contents the elaiosomes (of SERNANDER) of other myrmecochorous plants; that
ants are particularly attracted by the oil-containing caruncle, and can and will
carry about the seeds of gorse; and that the rectilinear distribution of gorse
bushes along actual or disused paths or roadways is only paralleled by the distri-
bution of such plants as the celandine along ant-runs.—J. M. C.
Anatomy of Gleichenia. —BoopLE and Hitry*° have investigated the vascular
Structure of Gleichenia, a genus interesting on account of its protostelic species.
—
% Bor. Gazetre 46: 53-55. 1908.
Be Kkisuiw Eos Mav, The structure and development of the ovule of Myrica
Gale. Annals of Botany 23:353-362. pl. 24. 1909.
SBAUER, K., anD Vouk, V., Zur Kenntnis des Heliotropismus der Wurzeln.
ch. Bot. Gesells. 27:151-156. 1909.
_ °*5 Weiss, F. F., The dispersal of the seeds of the gorse and the broom by ants.
New Phytol. 8:81
34 LIN
Ber. Deuts
—89. Igo9.
a * Boopte, L. A., AND Hixey, W. E., On the vascular structure of some species of
leichenia, Annals of Botany 23:419-432. pl. 29. 1909.
320 3 BOTANICAL GAZETTE - [octoBER
G. pectinata was especially studied, whose rhizome BooDLE3’ had discovered to be
solenostelic. This has now been confirmed, solenostely with leaf gaps being
found. It is concluded that Eugleichenia represents a series of reduction forms
from the Mertensia type (represented by G. flabellata), and that Mertensia includes
the most primitive species as well as the most advanced (G. fore in which a
solenostelic structure has been derived from a protostelic.—J. M. C.
. Ovule of Julianiaceae.—Miss KrrsHaw?* sees in the integumental vascular
strands and free nucleus of this recently established Mexican family a suggestion
of relationship between Juliania and Juglans, and especially in the association of
this structure in both genera with the outgrowth at the base of the ovule known
as the obturator. The suggested connection with Anacardiaceae is confirmed by
the integumental vascular strands of Mangifera, but in that genus there is no
indication of an obturator.—J. M. C
Chlorophyll in evergreens.—Miss CAcitie STEIN reports%® that crude chloro-
phyll (i.e., all the pigments) increases in amount with the season, and from
February to March far more than from March to May; from that time on it seems
about constant. The chlorophyll proper increases likewise and decidedly more
than the xanthophyll. This, she suggests, may be due to the conversion of the
xanthophyll into oa ee but Kout’s experiments strongly antagonize such
an explanation.—C. R. B
Stock and scion.—At a meeting of the Botanical Society of France last March
GRIFFON discussed the results of his numerous experiments in grafting during
1908,4° and declared that, whatever the plants employed (Solanaceae, Legu-
minosae, Compositae), and whether the graft was simple or mixed, there was 10
trace of asexual hybridization, but further confirmation of the specific independence
of the stock and scion.—C. R. B
An abnormal Funaria.—Drxon*™ describes a plant of Funaria hygrometrica
from Tonduff having the perigonial leaves fringed by a double row of protuberant
and more or less flask-shaped cells which are supposed to function as reservoirs
of water oC to the paraphyses for keeping the antheridia well supplied.
=e R. B
37 Boones L. A., On the anatomy of the Gleicheniaceae. Annals of Bae -
15:703- Igor
38 Ceasar E. M., Note on the relationship of the Julianiaceae. Annals of
Botany 23 :336, 337. 1909
39 STEIN, CACILIE, ine zur Kenntnis der Enstehung des Chlorophy llpigmentes
in den Blattern immergriiner Koniferen. Oesterr. Bot. Zeits. 59:231-245, 262-269:
1909
4° GRIFFON, E., Troisitme série de recherches sur la greffe ai plantes herbacées.
Bull. Soc. Bot. France §6:203-210. pis. 3, 4. 1909
4 sien H. N., A remarkable form of PES hygrometrica. Bryologist 12+ seis
- pl. 5. 1909.
No. 5
November 909
Editors: JOHN M. COULTER and CHARLES R. BARNES
CONTENTS
‘done Fungus Parasites of Algae : ay ad gcEs : { Cy
on in Synchytrium a ; a3 "Robert F. - Griggs
| George B. Bsn
Croley of Cutleria and fazerey ! ie , : Shigeo “f
- aes at eto Se oe =
' The University of Chi azo
CHICAGO and NEW YORE ys
‘William ‘Wesley and Son, London : a es ‘S
ete oe) ; 3 =
The Botanical Gazette
- @ Montbly Journal Embracing all Departments of Botanical Science
.” Joun M. CouLTER and CHARLEs R. BARNEs, with the aoa of other members of the
botanical staff of the University of Chic
Issued November 15, 1909
. XLVI CONTENTS FOR NOVEMBER 1909 No. 5
ME FUNGUS PARASITES OF ALGAE (WITH SEVEN FIGURES). George F. Atkinson - ~ 22 g2t
ro IS IN SYNCHYTRIUM (wirn PLaTEs xvi-xvil). Robert F. Griggs - - - - 339
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a
VOLUME XLVIII NUMBER 5
BOTANICAL GAZETTE
NOVEMBER 1909
SOME FUNGUS PARASITES OF ALGAE"
GEORGE F. ATKINSON
(WITH EIGHT FIGURES)
About twelve years ago I was giving considerable attention to the
study of the parasites of the algae in the vicinity of Ithaca, N. Y.
At that time I hoped that the investigations might eventuate in a
Monograph of the Chytridiales of the Cayuga Lake basin. The
Pressure of other investigations has almost completely interrupted
these studies. Because of our limited knowledge of the occurrence
and habits of these interesting fungi in North America, it has seemed
to me desirable that the observations already made should be recorded,
In the hope that this may stimulate a greater interest in these plants.
As a result of the studies three papers have already been published.
An extended paper on the genus Harpochytrium in the United States
Was published in 1903,? a summary of which later appeared in the
Journal of mycology in 1904.3 A short note on the interesting behavior
of the zoospores of Rhizophidium globosum while escaping from the
Zoosporangium was published in 1894.4 This behavior related to the
habit of their sensing or feeling the exit opening in the sporangium,
which they do by means of pseudopod-like extensions of the proto-
Plasm in different directions, after having come to rest on the inside
of the zoosporangial wall. In case they happen to come to rest close
by the exit they “feel” it by one of the pseudopods, and slide out.
‘ Contribution from the Department of Botany, Cornell University, No. 133.
* ATKINSON, G. F., The genus Harpochytrium in the United States. Ann. Myc.
1:479-so2. pl. Io. 1903.
*-———., Note on the genus Harpochytrium. Jour. Myc. 10:3-8- pl. 72. 1904-
é +++, Intelligence manifested by the swarm-spores of Rhizophidium globosum.
OT. Gazetre 192503, 504. 1894.
321
322 BOTANICAL GAZETTE [NOVEMBER
In case they are distant from the exit, not finding it they round up
into the motile zoospore form again and swarm around in the zoospo-
rangium for a time, and coming to rest make another trial. It is
evident that when the zoosporangium is filled with the zoospores the
latter will escape quite rapidly
for a time because so many of
them are crowded successively
against the exit. As the num-
bers diminish there is greater
freedom for swarming. The
zoospores then swarm around
and around in great circles
Fic. t.—Rhizophidium globosum(A.Br.) inside the wall of the zoospo-
eae A Ste Plant, eee after rangium, now and then coming
Renae BS tae cee to rest and feeling around for the
mature plant ready to form zoospores; exit. This same behavior has
C zoospores escaping; D much smaller been observed in the case of a
plants. . a
number of other species. In
addition to this a quite remarkable phenomenon was observed in
the case of another species, Rhizophidium brevipes, which will be
described below.
In the presentation of these observations I shall make no attempt
to arrange the genera in any natural order of relationship, this matter
being reserved for a future work. Since a number of species of
Rhizophidium were studied I will begin with this genus.
RHIZOPHIDIUM BREVIPES
This was collected in a pool beyond Forest Home, N. Y., 4 little
more than one mile from Ithaca. It was attached to the wall of a
fruiting cell of Spirogyra varians. The zoosporangium is oval with
a small apical papilla. The wall shows two distinct layers, an outer
rather thick one and an inner thin one. _At the time of the maturity
of the zoospores the papilla of the outer layer becomes gelatinized
at the apex, forming a minute opening about 4 » in diameter.
One very characteristic feature of this species is the very rudi-
mentary condition of the rhizoids. The very slender branched
rhizoids so characteristic of R. globosum and other species appeat e
awe
1909] ATKINSON—FUNGUS PARASITES OF ALGAE 323
be absent. The penetration tube of the zoospore forms a short stalk,
_ which projects but a short distance within the cavity of the host cell.
This rudimentary condition of the rhizoids recalls that of Harpochy-
trium hedenii Wille, though in the latter it penetrates only the outer
lamella of the wall and flattens
out in the form of a disk in the
middle lamella, or merely pene-
trates a thin layer of slime on the
host and flattens out on the outer
_ wall (ATKINSON 1903). This
_ penetration tube serves also as
_ the absorbent organ for such food
_ as the plant obtains from the
4 fluids within the gametangium of
_ the host surrounding its zygo-
spore. The zoosporangium
measures 21-24 “, while the zoo-
Spores are about 3 » in diam-
eter, with a single cilium and a
Fic. 2.—Rhizophidium brevipes Atk.
A mature zoosporangium crowded with
zoospores, outer layer of wall at exit pore
dissolving, inner layer projecting as a
papilla before the rupture, plants attached
to a gametangium of Spirogyra contain-
ing zygospores; B zoo i
C two zoospores, unable to escape by exit
pore, have germinated and are attempting
: Prominent oil drop.
The species was first observed
_ Mma cell preparation which was
: made on April 24, 1895, at about
_ 4%.M. The zoosporangium was
_ mature and the protoplasm finely granular. In the course of half an
si hour from the time of the first observation, the granules began to
_ 4iTange themselves in numerous small groups, the beginning of the
formation of the zoospores. Very soon these began to disappear and
_ Were gradually replaced by a prominent oil drop for each group of
Stanules. Each oil drop was surrounded by a hyaline mass of homo-
8&neous protoplasm. The preparation was watched for the greater
: part of the time from 4 p. M. until 6 P. M., and fresh water was fre-
7 quently drawn in, in order to hasten the development and maturity
Of the zoospores. At this time it appeared that the zoospores would
_ hot become mature under an hour, and the preparation was placed
q ‘na moist chamber until 7 p.m. It was then examined and fresh
_ Water added. The apical portion of the outer wall was dissolved;
in the apex of the tube; D same
showing how the zoospores retreated from
the first tubes and after swarming around
for the second time attempted to escape
again by the germ tubes. -
324 BOTANICAL GAZETTE [NOVEMBER
soon the inner wall at this point became ruptured, and precisely at
7 P.M. the zoospores began their escape. The number of zoospores
was very large and they were packed so tightly in the zoosporangium
that it was impossible for them to make other than slight amoeboid
movements. Those at the apex slowly moved through the opening
one or two at a time, so that the number could be readily counted.
In passing through the opening the zoospore puts forth a stout
hyaline projection which feels and leads the way, and then the
body slowly moves through. On the outside, at the mouth of the
zoosporangium, each zoospore rests for a short time, during which
a few plastic movements are exhibited; then it rounds off and darts
away.
When 50 or 60 zoospores had made their escape in this way the
space in the zoosporangium was not so crowded, and a few of those
at the center began active swarming movements, while those at the
periphery of the sporangium were quiet or only exhibited plastic
movements, and those nearest the opening continued to escape in the
manner described. This continued until there were very few still
within the zoosporangium. The remainder of the zoospores were
all swarming, and at times some of them would come to rest on the
side of the wall, put out by amoeboid movement a short pseudo-
podium, and feel evidently for the opening. Not finding it they
would swarm around within the zoosporangium again, and again
come to rest, maneuver for the opening, and on finding it escape.
This manner of finding the opening is the same as that described
for R. globosum (ATKINSON 1894), but as the opening is larger than
in that species, the body of the zoospore does not become constricted
at the passaze. At 7:18 p.m. all but four of the zoospores had made
their escape, and in four minutes more two of these had escaped,
leaving two still within the zoosporangium. ‘These were watched
for an hour longer, and they divided the time in swarming and feeling
for the exit, but were unable to escape; though several times they
located themselves directly at the opening, they seemed to be insen-
sible of it.
The preparation was placed in the moist chamber and left for the
night. On the following morning both of the zoospores were found
located on one side of the zoosporangium and each had germinated.
Ig09] ATKINSON—FUNGUS PARASITES OF ALGAE 325
_ The slender germ tube, having penetrated the wall of the zoospo-
_ Ttangium, extended ina tortuous course for a distance of 15-20. The
_ preparation was examined several times during the day. Since one
of the zoospores was located not far from the wall of the spirogyra, it
was hoped that the thread would find the cell and enter it, inasmuch
__ as it was pointed in that direction. The preparation was left in this
condition during another night, the slender tube of the zoospore
__ hearest the spirogyra cell not yet having reached it. On the following
a Morning the preparation was examined again, and I was surprised to
5 find that one of the zoospores was on the other side of the zoospo-
Tangium. Close examination showed that both had moved during the
night. Not being able to find any suitable nourishment, the proto-
_ plasm in each germinating cell had migrated back from the inclosing
_ Membrane into the zoosporangium, formed a zoospore, and had
_ Passed through a second swarming period. Then coming to rest
_ 4gain they had germinated, the germ tube of each having again
_ enetrated the wall of the sporangium and formed a slender tube
a 15-20 long. The preparation was kept for a day longer, but the
_ Zoospores did not form again.
This behavior of the zoospores is quite interesting, since it mani-
fests not only a sort of “ingenuity” in the attempt to escape from the
Z0osporangium, but, what is more important, the tendency, under
_ ©értain conditions of existence which prevent the zoospore from
_ Seeking a host cell by the normal planetic method, to migrate in the
form of a true mycelial tube, which is quite different from the very
q delicate slender absorbent rhizoids normally developed from the germ
__ tube in other species of the genus.
Rhizophidium brevipes, n. sp.—Zoosporangia oval, 21-24 u in diameter, with
4 papilla at the apex, in which the exit pore is formed. Rhizoidal apparatus
very rudimentary, consisting of the short, blunt, unbranched entrance tube
Of the Zoospore, which projects but a very short distance beyond the inner
: in diameter.
= On walls of gametangia of Spirogyra varians in which zygospores are formed.
_ Vicinity of Ithaca, N. Y.
Zoosporangiis ovatis, apici uno, brevi, papilliformi ostiolo, basi, uno brevi,
ga — tubulo. Zoosporis ovoidiis, 3 # latis, una guttula hyalina et uno cilio
_ Praeditis,
_ lamella of the wall of the host. Zoospores oval with an oil drop, uniciliate, 3 4
326 BOTANICAL GAZETTE [NOVEMBER
RHIZOPHIDIUM SPHAEROCARPUM
Rhizidium sphaerocarpum Zopf, Nova Acta Leop.-Carol. Deutsch. Akad.
47:202. pl. 19.. figs. 16-27. 1884.
Rhizophidium sphaerocarpum A. Fischer, Rabenh. Krypt. Flora Deutschl.
Oesterr. u. Schweiz 2 Aufl. 4:95. 1892
What I have taken to be this species occurred in abundance on
threads of Mougeotia parvula collected in a gutter on Thompson St.,
Ithaca, N. Y., April 7, 1895. The zoosporangia are oval in form
and vary considerably in size, the larger ones measuring 16-18X
18-20 #, while the smaller ones are about 1oX11 ¢. They occur
singly or in groups of two to four, the smaller ones more commonly in
groups and the larger ones rarely so. The rhizoids are very much
reduced, consisting of a few very short branches from the short
entrance tube.
The wall of the zoosporangium consists of two lamellae, an outer
stout lamella and a thin inner membrane. This is very well seen in
the dehiscence of the zoosporangia. At maturity the apex of the outer
wall of the zoosporangium dissolves, forming a large circular opening
for the exit of the zoospores. Through this the inner membrane
projects in the form of a short broad papilla by the swelling of the
epiplasm. The final rupture of this membrane sets the zoospores
free, and the large opening permits their rapid escape. The exit pore
measures 5—6 » in diameter in the larger forms, and in the smaller
ones is proportionately larger, being 4-6 w in diameter, some of the
smaller zoosporangia appearing like cups when open. The zoospores
are oval, possess a long cilium and a prominent oil globule, and
measure 1.5-2 in diameter. In germination, if the germ tube 1s
directed toward the wall of the host cell, it penetrates the wall, and
then the zoospore enlarges to the size of the mature plant, becoming
the zoosporangium. If, however, as sometimes happens, the germ
tube is directed away from the wall, or along its surface, it may gTOW
to a considerable distance, sometimes reaching a length of 30 - The
zoosporangia sometimes grow so as to appear attached by their side
instead of by their base, and the opening is then at the side (fig. 3; C).
In nearly all of the larger specimens (which may prove to be
a different species) the effect on the host cell was quite remarkable.
The host cell not only becomes considerably larger near the middle,
!
3
SE, eA PS eee
eee ee Pee
ST) ee a ee ee ee ee Ne ene es eee |
er eine ps eee verse
1909] ATKINSON—FUNGUS PARASITES OF ALGAE 327
but is very much elongated. Frequently at the middle it is not much
larger, while on each side an enlargement occurs (fig. 3, D,’G). The
_ stimulus which causes the increase in the length and size of the cell
also increases the development of the chromatophore. When this
influence ceases the chromatophore begins to degenerate, the color
Fic. 3.—Rhizophidium s
showing entrance of germinating zoospores, and mature plant with
Spo a
Plants also attached to the host; C mature empty zoosporangia, showing one with the
Penetration tube on the side; D mature plant, large form, showing hypertrophy and
Curving of host cell ; £ mature plant with escaping zoospores, showing strongly curved
host cell; FG showing hypertrophy of host cell; H—M different stages in the opening
of the 2oosporangium and escape of the zoospores; A-G original; H—M after Zopr.
fades, the structure breaks down, and the processes of dissolution
Separate it into small particles with the pyrenoids more distinct, all
Coalescing into an amorphous mass, which gradually flows toward the
Middle of the cell where the sporangium is located. This may be due
Partly to the fact that the cell of the host is larger at that point, as well
328 BOTANICAL GAZETTE [NOVEMBER |
as to an influence which the parasite exerts upon it, for it is possible
that the crowding of the chromatophores from each side toward the
middle may cause the two enlargements near the middle with the
constriction between them (jig. 3, G). Not only does the influence of
the parasite excite these changes in the host cell, but it also causes the
cell to become more or less strongly arched at the point of insertion of
the sporangium, the sporangium being in the concavity of the arched
thread. This effect has only been noted in connection with the
larger forms, except where the smaller ones are several in a group,
and here the curving of the thread is slight in comparison with that
which exists in the case of the larger sporangia. Zopr (I. c.) does not
mention any similar hypertrophy of the host cell caused by this
species, nor is it shown in his illustrations. He figures the plant on
Spirogyra. A. FiscHeEr (/.c.) reports it on various filamentous Con-
jugatae and Oedogoniaceae, but does not mention any hypertrophy
of the host.
Germinating zoospores have been observed in this species in which
the germ tube may become directed away from the host and develop
a mycelial tube 15-20 » in length.
RHIZOPHIDIUM MINUTUM
This species was collected on Spirogyra varians in a pool beyond
Forest Home, N. Y. (about one mile from Ithaca), April 23, 1895.
a It frequently accompanies Lagenidium, but
Re _ also occurs independently of it. The ane
rangia are sessile, very small, obpyriform oF
_ Fic. 4.—Rhizophidium flask-shaped.-. Thus the species belongs to the
sae nha oehaahe longata section of the genus. The zoosporan
and aotepceeal: ’ gia are 5-6 # in diameter. At the base are a
few slender rhizoidal threads which extend 4
short distance in the host cell content. The form of the 2005?
rangium thus presents a broad and prominent apical papilla, the end
of which becomes gelatinized at maturity of the zoospores, forming
a circular exit pore. The zoospores are few in number, two to four
in the cases observed. They measure 2. 5 » in diameter, and are
provided with one cilium and a prominent oil drop.
Rhizophidium minutum, n. sp.—Zoosporangia obpyriform or flask-shaped,
broadly papillate, 5-6 # in ae sessile with a few slender rhizoidal filaments
3
i
Igog] ATKINSON—FUNGUS PARASITES OF ALGAE 329
at the base in the host cell. Apex opening by a single pore. Zoospores two to
four in a zoosporangium, oval, uniciliate, with a single oil drop, 2.5 « in diameter.
On Spirogyra varians in the vicinity of Ithaca, N. Y.
Zoosporangiis obpyriformibus, 5—6 latis, apice una lata papilla, basi fila-
mentis brevibus radiciformibus. Zoosporis ovoidis, 2.5 #, una guttula hyalina
et cilio simplici attenuato praeditis.
LAGENIDIUM RABENHORSTIS
This species was first found in a species of Spirogyra in a stream
of slow-running water in the valley south of the city of Ithaca. Ithas
since been found in various species and appears to be quite common.
The fungus attacks the vegetative cells and those just about to con-
jugate. The zoospore enters the cell wall by a small perforation, the
slender entrance tube growing usually nearly to the center of the host
cell, where it enlarges to the size of the vegetative thread of the
parasite. The general course of the threads is parallel with the axis
of the spirogyra cell, though frequently tortuous and curved, with
here and there short branches. The threads are usually stout, varying
in diameter from 3 to 8. At the ends of the cell of the host they
curve around and frequently extend back to the other end, one to
three and four threads thus lying in a single cell. The protoplasm
possesses numerous highly refringent granules and there are also
vacuoles at short distances. In other cases the thread may be strongly
curved, or even coiled at various points within the end of the cell.
The chromatophores of the spirogyra are broken down and usually
adhere to the threads of the fungus here and there, giving portions
of them a green appearance in the early stages, and later a greenish
brown as the chlorophyll becomes more and more disorganized. All
traces of the chlorophyll at length disappear, and the fungus, lying
in a disorganized mass of transparent protoplasm, is then seen
distinctly throughout its entire length. In other cases the fungus
thread may be permanently soiled by the brownish matter of the
disorganized chlorophyll.
The exit tubes are developed from the ends of the threads, or from
the ends of the short lateral branches, or from the side of the main
0 * Zopr, W., Ueber einen neuen parasitischen Phycomyceten aus der Abtheilung der
sporeen. Bot. Verein Prov. Brandenburg 20:77—80. 1878. See also, Zur Kennt-
330 BOTANICAL GAZETTE [NOVEMBER
thread itself, in the latter cases usually arising from the outer con-
vexity of a curved portion of the thread. The exit tube is about 2»
in diameter and projects but a little way outside of the wall of the host.
The tube develops quite rapidly. In observations on cell cultures
where I have been watching for the migration of the protoplasm
through the exit tube, cos ones have been observed to develop in
two to four hours time. The
end of the tube becomes gelati-
nized and the protoplasm moves
in a quite rapid stream through
the tube, the small spherical mass
of protoplasm at the mouth of the
tube growing rapidly in size until
all the protoplasm has passed
through, which takes only a few
seconds. In a few moments
Wiha See i rotary motion begins, sow at
Walker cae prosporangia, which are fSt. Soon the constriction of the
sections of the thallus; B zoospores form- mass occurs in lines over the sur-
ing at the apex of the exit tube; C zoo- face, in such a way as to divide
or and small particles separated from he ua teee inta portio ns ac-
cording to the size of the mass
and the number of the zoospores to be formed. In this species I
have not observed any inclosing membrane, nor any evidence that
such a membrane exists, though Zopr (i. c., p. 149, 1884) describes
and figures one. The constriction goes on from the surface toward
the center, and soon the cilia are developed, their slow waving
aiding in the slow but perceptible oscillatory motion of the mass.
Plastic movements of the mass and the developing individuals
also accompany the other movements. When division has become
nearly complete, small portions frequently become constricted from the
ends of the ovate to reniform individuals, the constriction becoming
deeper and deeper, until in many cases the small portion becomes
separate from the larger mass (jig. 5, C). These can be seen to be
separate from the larger ones by the gliding motion of the zoospores
over each other, and over the smaller bodies. The movements become
more and more active, occasionally one zoospore pulling strongly in
1909] ATKINSON—FUNGUS PARASITES OF ALGAE 331
one direction and separating itself from the group by several milli-
meters; then it is drawn back again to its fellows as if by a retractile
cord; then another will separate in the same manner, only soon to be
drawn back again. This pulling away and returning becomes more
and more accentuated each time, until finally one of the zoospores
makes its permanent escape, leaving the others to struggle still for
freedom. One by one, or two or more at a time, they escape in this
manner and whirl away. This mode of escape would indicate that
there is no inclosing membrane.
Before the escape of the zoospores, in cases where small portions
of the zoospores have become separated, they may fuse or conjugate
with the large ones again, but whether with the same one from which
they were separated or with a different one could not be determined,
since the gliding and rotary movement of the individuals and the
mass would prevent absolutely the following of the separate ones
through their various evolutions. DEBary® (p. 37, 1881) first
observed a separation of portions of the protoplasm and their fusion
again with the parent masses in the formation of the oospores of the
Saprolegniaceae, and it has since been observed in the oospores by
Hartoc? (p. 24) and Humpurey’ (p. go). It was first observed in
the zoospores of the Saprolegniaceae by Rothert® (1887, also p. 322,
1890; see also HaRroG, J. c.). When fusion did not take place before
the zoospores made their escape from the group, the smaller portions
would not then fuse with the larger ones, even if they came by acci-
_ dent in contact with them, so far as I was able to observe. In other
Cases the small portions of protoplasm might become partially
separated from the larger ones, and the zoospores escape with a
minute appendage attached either at one of the extremities or upon -
°DEBary, A., Untersuchungen iiber die Peronosporeen und Saprolegnieen und
os Grundlagen eines natiirlichen Systems der Pilze. Beitr. Morph. u. Phys. der Pilze
431-145. pls. 1-6. 188r.
7 Hartoc, M. M., Some problems of reproduction. Quart. Jour. Micr. Sci.
33: ee 1892
. REY, J. E., The Saprolegniaceae of the United States, with notes on other
Species, ies Am. Phil. S Soc. 17:63-148. pls. 14-20. 1893.
® RotHert, W., Die Entwickelung der Sporangien bei den Saprolognieen. Beitr.
Biol. Pf. 5:2 291-349. pl. IO. 1 ne This paper first appeared in Polish in the Pro-
ceedings of the Cracow Academ 17t 1887.
332 BOTANICAL GAZETTE [NOVEMBER
the more convex side, where it gave the zoospore the appearance of
being a “hunch back.”” Such zoospores would perform very curious
evolutions in their vain efforts to throw off the offending appendix,
but in no case observed did this separation take place after the zoo-
spores had separated from the group at the mouth of the exit tube.
The number of zoospores from a single zoosporangium is 2-8, as
stated above, or possibly a few more in some cases, the number
depending upon the size of the sporangium.
In one case observed, where the zoospores seemed to be rather
sluggish in their development and the movements not so active, the
form was not so pronouncedly reniform, but more nearly oval, and
after separating very little active movement took place, the individuals
soon rounding off as they do when ready to germinate. Two such
zoospores soon came in.contact and immediately fused into a larger
one, the fusion taking place in about ten seconds. The further fate
of these zoospores was not followed. This fusion may be due to the
peculiar conditions of environment, perhaps to the want of fresh
water in the limits of the cell culture. From some observations made
on the developing zoospores under similar conditions, it appears
possible that it may be due to the variations of tension existing between
the individuals and the original mass of protoplasm, the tension of
the entire mass being directed toward keeping the mass intact and
the tension of the individuals tending to separate the masses into
smaller individuals. Two cases were observed which had progressed
to some extent toward the formation of the zoospores. In one cas¢
there were two zoospores forming and in the other case four zoospores
were forming from the spherical protoplasmic mass, which shad
collected at the end of the exit tube after passing from the sporang!um-
In each case the zoospores were about one-third formed. The
preparation had been in the cell culture for two days and the water
had been replenished a few times, as it had partially evaporated, by
running fresh water under the cover from the edge, the cell cultures
being made simply between the cover glass and the glass slip and net
in a ring-cell, or vAN TreGHEM cell. The oxygen thus accessible
to the organism was very small, though this did not seem to hinder the
development during study, if water were added every few moments,
as would be necessary when the preparation was not protected in @
1909] ATKINSON—FUNGUS PARASITES OF ALGAE 333
moist chamber. While these two developing groups of zoospores
were under observation, the water, which had not been changed
for some time, slowly evaporated, so that a portion of it was removed
from under the cover. At this time it was noted that the dividing
protoplasmic mass, where there were two forming zoospores, was
fusing again, and soon the mass was spherical, with no sign of the
division which up to this time was quite marked, and showed all the
phenomena of movement and formation of cilia which accompany the
normal development of the zoospores, except that the movements
were not so active. Very soon also the four forming zoospores in the
other group were fusing and the movements had likewise ceased.
The fusion in this case also continued until there was no trace of the
forming zoospores, the mass was again spherical, and movement
had ceased.
Thinking this might be due to the want of fresh water, some was
quickly run under the cover glass, and the observation was renewed.
The smaller protoplasmic mass burst on the absorption of the water,
So great was the tension, but the larger one soon began slow rotary
movement again and the constrictions appeared a second time, indi-
cating the formation of four zoospores. This time the division pro-
ceeded, accompanied by all the phenomena of the formation of the
zoospores noted in the normal cases, until the zoospores were com-
plete and whirled away.
This would suggest that there were two opposing tensions in the
formation of the zoospores, one individual and under normal condi-
tions the stronger, and the other belonging to the mass and the weaker.
When the conditions favorable for the formation of the zoospores
ceased, the individual tension lessened to such a degree that it was
lower than that of the mass, and the separating smaller portions were
drawn together again in the common larger mass. These two
pposing tensions might possibly explain the peculiar behavior of
the zoospores when they still remain closely associated in the group,
how partially separating and again coming close together, continu-
ing this process of coquetting until the individual tension is strong
fnough to free them, in the case of those where there does not seem
to be any inclosing membrane. The tension of the entire mass
May possibly be somewhat similar to the force called adelphotaxy
334 BOTANICAL GAZEITE ~*~ [NOVEMBER
by Hartoc’® (p. 216) in the case of the escaping zoospores of
Achlya and Aphanomyces.
In some of the cell cultures in which numerous zoospores of
Lagenidium were developing, there were several sun animalcules
(Actinophrys sol). Some of these were so full of zoospores which
they had caught, that they appeared to be a rounded collection of the
zoospores, the convex outer portion of the zoospore only showing,
and the entire surface of the Actinophrys appearing like a piece of
mosaic made up of these unfortunate creatures. The delicate arms —
or rays of the Actinophrys radiated for a distance of 20-30 #, and in a
large number of cases which were observed, whenever a zoospore
passed within reach of these rays, no matter how swiftly it was moving,
it was suddenly paralyzed and halted; then the reniform shape
gradually became spherical and it was slowly drawn by “invisible
threads” to the body of the Actinophrys and slowly wedged its way
between those which had preceded it.
LAGENIDIUM AMERICANUM
Another species of Lagenidium, which seems to differ from any
described, was found in various species of Spirogyra (5. varians, S.
calospora, and S. insignis) collected in a pool beyond Forest Home,
April 11, 1895. It is parasitic in the zygospores and conjugating
cells of the spirogyras, but has not been observed to develop in the
vegetative cells... The vegetative phase of the fungus consists of
strongly curved and coiled tubes, 4-8 » in diameter, the size varying
so that the contour and diameter of the threads is very irregular.
It is profusely branched, and has also numerous short branches. It
frequently fills the zygospores so completely that the individual course
of the thread can be followed for only a short distance. At maturity —
the tube, as in the other species, is separated into segments of various
lengths by the development of cross-walls, forming the zoosporang!a.
Frequently there is a constriction at the septum. Numerous Z200Sp0"
rangia are developed in a single zygospore. The exit tubes are slender,
measuring about 2 « in diameter, and of variable length according to
the direction in which they emerge from the zygospore and the wall —
o Hartoc, M. M., Recent researches on the Saprolegnieae. Annals of Botany
2:201-216. 1888.
ee ee Se Ee Se
Be tkaiwa Lar <9 ee a ee
Un Te ae Tee, CTT oe
1909] ATKINSON—FUNGUS PARASITES OF ALGAE 335
of its parent cell. If the zoosporangium is located at the periphery
of the zygospore near the middle, the tube is quite short. In the case
of the zoosporangia which are located at the ends of the zygospores, the
length of the exit tube is considerably longer, even when it is directed
from the start perpendicularly to the wall of the parent spirogyra cell.
In many cases, however, the exit tube from the zoosporangia which
lie at the ends of the zygospore starts out nearly parallel with axis
of the spirogyra cell, or at some angle between this and the perpendicu-
lar. In such cases:the exit tube may be very long and tortuous,
frequently passing into the adjacent spirogyra cell and finally emer-
_ ging through the wall of the latter.
The protoplasm, with numerous small highly refringent granules
and a number of vacuoles, presents practically the same appearance
as in the case of the other species. It passes ina rapid stream through
the exit tube and collects in an irregularly spherical mass at the
extremity, from which in some cases it soon becomes free and floats
to a short distance. In ten minutes from the passage slight rotary
movements begin, the mass turning a short distance in one direction,
and then in a moment in the other direction, the movement becoming
faster and repeated at shorter intervals. a
In some cases the cilia can be seen as delicate rays, even before
the simultaneous constriction of the mass begins and they are slowly
lashing. In other cases they are observed very soon after the con-
striction of the mass begins which outlines the surfacgof the individual
Zoospores. No inclosing membrane was observed, and it seems
possible that it should exist if the cilia can extend for such a distance
‘Tom the mass. As the division proceeds the reniform shape of the
Individuals becomes more and more pronounced, and the movements
“come more and more violent. The individuals divide the time in a
quivering motion followed by the oscillatory movements and the
gliding over one another until they are apparently separate, now
®ne pulling off a short distance, then returning, and so on, until they
make their escape one after another or several at a time. After
“sparating from the group, movement in space is rather slow, as if
they were uncertain how to use the freedom gained. The individual
scillates and glides around in various curves, then becomes nearly
Stationary and quivers for a moment; then, one end remaining
336 BOTANICAL GAZETTE [NOVEMBER
stationary, the other executes in succession several jerks or nods as if
striking at something; then it enters upon another series of evolutions.
After a short time thus engaged, the activity of the zoospore increases,
the field covered by its evolutions becomes larger, and it is lost
from the field of the microscope. In some cases which were timed
the zoospores were separate in 25~30 minutes from the time the ~
Fic. 6.—Lagenidium americanum Atk. in zygosp f Spirog) A, Bsome empty
and some mature prosporangia; C from one prosporangium the protoplasm has just
issued from the exit tube; D plasma sphere or zoosporangium proper free from the
exit tube and floating in water; E formation of cilia where a zoosporangium is swim-
ming around as a multiciliat ; F, G different stages in formation and separation
of zoospores, the groups swimming around like a pandorina colony; H mature and
separate zoospore.
protoplasm passed from the exit tube. In those cases where the -
plasma vesicle at the end of the tube becomes free and floats away, —
the cilia develop on its surface, and it at first presents the appearance
of a multiciliate spore. Later the divisions occur in such a way aS
to leave two cilia with each forming zoospore, and the colony then
resembles a pandorina colony.
Lagenidium americanum, n. sp.—Plant body in the form of irregular tubes,
much branched, curved, and of unequal diameter, confined within the host zygote,
3-8 4 in diameter. Exit tubes slender, short, 2 4 in diameter, varying in len
but extending a short distance outside of the gametangium wall, of equal diameter
from the point where they pierce the wall of the zygote to the outer free end, thus
differing from the exit tubes of L. entophytum (Pringsh.) Zopf. Exit tubes arising
from the end of hyphae or branches, or from the convex side of curved or enlarged
portions. Zoosporangia of varying size, irregular and often branched, formed
from segments of the thallus. Plasma sphere at the end of the exit tube often
becoming free and floating away (the cilia then forming on the outside of the
Me ey ee ee
1909] ATKINSON—FUNGUS PARASITES OF ALGAE 337
sphere), and finally dividing into the individual zoospores, the whole resembling a
pandorina colony, but at last the zoospores separating. Zoospores reniform,
laterally biciliate, 4-6 5—7 u
n zygospores of S$ piri varians, S. insignis, and S. calospora, Ithaca, N. Y.
Mycelio inequali, curvato, ramulo irregulare instructo, 3-84 lato. Zoospo-
Tangiis irregularibus, saepe ramulosis. Ostiolo tubiformi tenuissimi aequali, 2
lato. Prosporangiis ramulosis sectionibus mycelii formatis. Zoosporangiis
vesiculosis, saepe deciduis, ciliis ornatis, ut coenobio Pandorinae natantibus,
postremo divisis, zoospores formantibus. Zoosporis fabaeformibus, laterale
biciliatis, 465-7 4. Hab. in zygosporis Spirogyrae, Ithaca, N. Y
PHLYCTOCHYTRIUM PLANICORNE
This genus, Phlyctochytrium Schroeter,*: differs from Rhizo-
phidium in the presence of a swelling on the penetration tube, just
inside the host cell wall, from which the delicate nutritive rhizoids
grow. Phlyctochytrium planicorne has been found
quite frequently in company with Lagenidium
americanum, in the cells of Spirogyra varians, Be
from the pool beyond Forest Home (near Ithaca).
The zoosporangium is a little broader than long,
measuring 68 m, and is broadest in the middle.
At the apex it is provided with four plain dentate
Processes around the exit pore. These dentate processes are char-
acteristic of one section of the genus (Dentigera ROSEN,'? SCHROETER,
0p. ¢., p. 79). The endophytic bladder-like base of the plant is
separated from the epiphytic zoosporangium by a constricted portion
at the point where the penetration tube passes through the cell
wall of the host. This base is about 3 in diameter, and from
it radiate several slender branching threadlike rhizoids. No zoo-
Spores have as yet been observed. While it very frequent'y accom-
panies Lagenidium, it is by no means confined to the cells affected
by the fungus, being found on other cells also.
Phlyctochytrium planicorne, n. sp.—Zoosporangium broadly elliptical,
6X8 u, armed at the apex with four plain teeth. Endophytic vesicle globose,
3H in diameter, with several radiating branched slender rhizoids.
On cells of § he fo varians, often accompanying Lagenidium americanum,
hear Ithaca, N. Y
G. 7.—Phlycto-
ee planicorne
ene J., in ENGLER & PRANTL, Pflanzenfam. 11:78. 1892.
*? Rosen, F., Ein Beitrag zur Kenntniss der Chytridiaceen. Beitr. Biol. Pflanzen
45253-266. pls. 13, 14. 1887.
338 BOTANICAL GAZETTE [NOVEMBER
Zoosporangio ellipsoideo, 6X8, apice 4 cornuis ornato. Cellula inferiori
3eulata. Hab. in Spirogyra varianti.
PHLYCTOCHYTRIUM EQUALE
This species inhabits the cells of Spirogyra, having been found in
the cells of S. insignis, collected in the pool beyond Forest Home,
April 17, 1895. The epiphytic sporangium
and the subsporangial endophytic base are
about equal in size, being spherical in form
and about 6 #in diameter. The mouth of the
sporangium appears to have two small teeth,
which may be the walls of a short canal.
From the base of the subsporangial part of
the plant are several branching rhizoid-like threads. Zoospores
have not been observed.
Fic. 8.— Phlyctochy-
trium equale Atk.
Phlyctochytrium equale, n. sp.—Zoosporangium globose, sessile, about 6m
in diameter. Subsporangil base equal in size, with several long branched
rhizoid filaments from its
Zoosporangio globoso, seat 6» lato, basi subsporangiali aequalt, rhizoideis
filamentibus ramulosis praedito. Hab. in S roe insigne.
A few other species have been Spaced but not studied further
than for their identification. They are as follows:
Lagenidium enecans Zopf (p. 154, 1884), in Stauroneis phoent-
centron and Cymbella lanceolatum, in swamps near Freeville, N. Y.,
May 5, 1
ea ie bulligera (Zopf) Fischer (Rhizidium bulligerum Zopi,
P- 195, 1884), in Spirogyra insignis in pool at Forest Home, N.Y.)
April 17, 1895.
Rhizophidium ampullaceum (A. Br.) Schroeter, on sterile threads
of Oedogonium, Freeville, N. Y., May 4, 1895.
Ectrogella bacillariacearum Zopf (p. 175, 1884), in diatoms, south
end of Cayuga Lake, Ithaca, N. Y.
CoRNELL UNIVERSITY
MITOSIS IN SYNCHYTRIUM
4 wits SOME OBSERVATIONS ON THE INDIVIDUALITY OF
THE CHROMOSOMES:
ROBERT F. GRIGGS
(WITH PLATES XVI-XVIII)
_. The nuclei of Synchytrium decipiens, a leaf parasite of the hog
F peanut, were shown in previous papers to be derived very largely by
-amitosis. Several sorts of amitosis were observed, two of which,
nuclear gemmation and heteroschizis, differ considerably from the
“ordinary. process of amitosis. The nuclei derived by these direct
_ divisions were shown to be persistent, and some of them were observed
: _to divide by mitosis. This with other facts led me to the conclusion
4 “that the nuclei derived by these processes of amitosis are normal,
The purpose of the present paper is to describe the mitoses which
4 follow, to correlate them with the amitoses, and to discuss the theo-
_ Tetical bearing of the facts thus presented.
I would here repeat my acknowledgments to my friend, Professor
or. L. STEVENS, of the North Carolina College of Agriculture and
_ Mechanic Arts, who furnished the material used in the investigation
and gave the suggestions that originally aroused my interest in the
_ Problem. The sections were cut 2-10 thick and stained with
_ Haidenhain’s iron alum hematoxylin and with anilin safranin and
_ gentian violet.
c As in coenocytes generally, all the nuclei in a cyst pass into mitosis
3 simultaneously and divide with equal rapidity, so that all of them are
very nearly in the same stage throughout. This fact may be utilized
for Overcoming one of the most serious obstacles encountered in
2 investigating the cytology of this plant—the difficulty of estimating
_ the relative ages of the different structures in the absence of any
& ‘Contribution from the Botanical Laboratory of the Ohio State University,
; No. XLIX.
339] [Botanical Gazette, vol. 48
340 BOTANICAL GAZETTE [NOVEMBER
indications external to the nuclei themselves—for those cysts which
are of critical age usually contain short series of closely connected
stages which frequently enable one to assure himself concerning diffi-
cult points, such as the formation of the spindle or the origin of the
asters. Nuclei of widely different phase in the same cyst are very rare:
fig. 5 is a case where the small nuclei in the cyst were still in the
vegetative condition while the large nuclei had passed into spirem;
fig. 35 shows a case where the small nuclei had reached late anaphase
while the large nuclei were still in metaphase; fig. 36 of the previous
paper (5) is a case where the reverse was true, the small nuclei being
in metaphase while the large ones were in anaphase. It would be a
matter of great interest to ascertain the mechanism by which the
nuclei are kept in phase. While not throwing much light on the
nature of the stimulus, the behavior of newly segmented cysts is
interesting in this connection. In such a cyst, long before the walls
of the zoosporangia appear, while the segments are still separated
from each other only by an exceedingly delicate plasmatic membrane,
each nucleus has become entirely independent of the others; and one
finds vegetative nuclei, metaphases, and telophases in adjacent seg-
ments, showing how slight a separation suffices to establish the com-
plete physiological autonomy of the individual nucleus (fig. 33):
All of the mitoses of Synchytrium are of the same type. It is
true that none of the later nuclei undergo such a shrinkage in volume
with its associated peculiarities as occurs preparatory to the primary
mitosis (STEVENS 18), but these phenomena are probably due simply
to the enormous size of this overgrown nucleus. It may be recalled
that similar peculiarities are usually observed in very large nuclei
wherever they are found. CHAMBERLAIN (1), for example, was not
able to interpret the structures he found in the enormous egg nucleus
of Dioon. But aside from these peculiarities of the primary nucleus,
the only differences that could be detected were in the size of the
spindles, those in the early stages being fairly large, while those in the
last mitoses of the sporangium are exceedingly minute (figs. 32-34):
In the resting nuclei of Synchytrium the chromatin is all concen
trated in a single globular karyosome (jigs. r, 31). Except in those
cases where vacuoles have appeared on the removal of the chromatin
preparatory to mitosis or nuclear gemmation (fig. 36), the karyosome
Pi Ra ai at eS ey
aa al
a a ie a Sites
OAR Sr ei ey) de a Ath
ore
ll a Rome hes
1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 341
is an entirely irresolvable, deeply colored body, whether stained with
hematoxylin or safranin. Besides the karyosome there may be a
few deeply staining granules on the nuclear membrane, but there is
nothing corresponding to the chromatin reticulum characteristic of
the vegetative nuclei of many cells. The only nuclei in which the
chromatin approached the condition of a reticulum were located in
the degenerating cysts occasionally found.
The spirem
The early prophases of mitosis consist in the formation of the
spirem from this compact karyosome. This is brought about in the
most*direct manner possible. The karyosome first separates into
a number of irregular chromatin masses (figs. 2, 30); next delicate
linin bands appear connecting these granules with the nuclear mem-
brane (fig. 3); and along these bands the chromatin granules are
distributed over the nuclear cavity, forming the expanded spirem
(ig. 4 from the same cyst as fig. 2).
Only a portion of the spirems of Synchytrium, however, are destined
to pass into mitosis. A large proportion of them undergo nuclear gem-
mation or some other form of amitosis. In view of theoretical con-
siderations which will be discussed later, it is of the utmost importance
to determine whether the spirems of amitosis are of the same nature
as those of mitosis, or whether they are different in kind and present
only accidentally an optical similarity. In most cases it is easy to
distinguish the two sorts by the cysts in which they occur. In those
cysts which are in the prophases of mitosis, the nuclei are in general
very nearly the same size and evenly spaced off from each other,
while in the amitotic cysts there are small nuclei in groups or clusters
4S well as the large spirems. Many such spirems have a strikingly
different aspect from the mitotic spirems. They are coarser (jig. 37),
the chromatin granules are very much larger, and the linin strands are
short and heavy; whereas the mitotic spirems are characterized by
linin threads and chromatin granules of various sizes lying side by
Side. In the amitotic spirems each of the chromatin granules is
evidently simply the karyosome of a small nucleus, for the formation
of which the spirem is a preparation. It would thus appear that the
two classes of spirems are entirely different from each other, but
342 BOTANICAL GAZETTE [NOVEMBER
unfortunately for this view a very large proportion of the amitotic
spirems are intermediate, or so closely resemble the mitotic spirems
that they can be distinguished from them only by the character of the
cyst in which they occur (fig. 41, a, b,c). It seems impossible therefore
to determine certainly whether these two classes are distinct or
whether they are of the same nature.
The origin of the spindle
In those cells where the spindle is intranuclear, there seem to be
two types of spindle formation. In the first type, which occurs in
the ascomycetes (e. g., Phyllactinia, HARPER 8) and brown algae
(e.g., Fucus, YAMANOUCHI 21), the centrosomes are permanent
organs of the cell and form the spindle by moving around the nucleus
so as to include the chromosomes between them, organizing the
spindle by the union of those astral rays which penetrate the nucleus
in a manner very similar to that prevalent among animals. This
process is very conspicuous and has been observed and figured by
numerous investigators. In the other type, which occurs in the
oomycetes (e. g., Saprolegnia, Davis 3; and Albugo, STEVENS 16),
centrosomes are either small or absent in the early stages; to this
type the spindles of Synchytrium belong. Here the determination
of the origin of the spindle is very difficult. This probably accounts
for the fact that very few of those who have figured such mitoses have
given a series of figures of the prophases complete enough to throw
much light on the formation of the spindle.
When first seen, the spindle of Synchytrium, which is thrown
directly across the cavity, is not distinguishable by its staining reaction
or otherwise from a strand of the spirem (figs. 6-8). It is therefore
difficult to be certain just when the spindle appears or what it comes
from, but it gives every indication of being differentiated from 4
spirem strand. Very soon, however, it becomes sharply pointed and
quite different from the spirem, which now begins to be drawn 1D
around its equator (figs. 9, 10). Contraction continues and more
definite connections between the chromatin and the spindle fibers are
established (jigs. 11, 12). In this condition the spindle often appe@t>
bipolar (fig. 9), which emphasizes the similarity of the linin strands
and the spindle fibers. By further contraction this much shortened
1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 343
spirem is converted into the four chromosomes of metaphase (figs.
14,15). Very frequently, however, the contraction is so pronounced
that the individual chromosomes cannot be made out in the chromatic
mass at the equator (jig. 13).
Some spindles show nucleoli lying in the nuclear cavity beside
the spindle; in others no nucleolus is present. No difference was
observed between the spindles with nucleoli and those without; but
it was observed that in any given cyst all of the spindles were alike
in this respect—either all had nucleoli or all lacked them. In rare
cases more than one of these bodies were present. The nucleoli
remain beside the spindle till after the daughter nuclei have separated
in telophase (figs. 22, 29, 33), when they disappear.
As soon as the spindle is formed, the nuclear membrane with the
small chromatic granules which are imbedded in it begins to disappear
(figs. 10-15), soon leaving the spindle free in the cytoplasm. As is
usual with the intranuclear spindles of fungi, the metaphase in which
the chromatin is all concentrated at the equator, if we may judge
from the frequency with which it is observed, is of long duration.
This is in contrast with the mitoses of the higher plants, where good
metaphases, far from being the commonest, are observed less fre-
quently than other stages.
Anaphase and telophase
The spherical chromosomes are pulled away from each other in
the usual manner by the fibers of the spindle, which are exceedingly
heavy (figs. 15,17). In early anaphase, figures stained with anilin
safranin and gentian violet show the chromosomes red and the spindle
violet but in hematoxylin preparations the chromosomes are difficult
to differentiate from the spindle fibers. This difficulty increases in
late anaphase until it becomes impossible to distinguish chromatic
from achromatic structures, even when stained with the safranin-
Violet combination. When the chromosomes pull apart, they remain
connected by heavy fibers similar to those by which they were pulled
away from each other (fig. 18), which persist long after the chromo-
somes become lost in the condensed mass at the poles (jig. 19).
These deeply staining fibers are very conspicuous and give a character-
istic appearance to side views of anaphases, which somewhat resem-
344 BOTANICAL GAZETTE [NOVEMBER
bles the daughter stars formed in mitoses where the chromosomes
themselves are elongated. These fibers may be used to determine the
chromosome number, since each one of them is connected with a
chromosome. This can be done more easily in this stage than in
metaphase, because the fibers are larger than the chromosomes and
because they spread apart as they separate, sometimes giving views
of all four at once, while in any other stage the full number can be
seen only from polar view (jig. 16).
These radiating bands of fibers are now drawn in, leaving the
two poles connected only by a central band (figs. 20, 22), which
becomes considerably attenuated as the two chromatic masses move
farther and farther apart. The daughter nuclei become separated
by distances considerably greater than the original length of the
spindle. In moving apart one or both of them frequently swerves
from the axis of the spindle, so that the connecting fibers meet at a
considerable angle (fig. 33). As was indicated in the paper on the
reconstruction of the nucleus (Griccs 4), this habit makes it almost
impossible to associate the daughter nuclei in pairs after the wisps
of spindle which point to the original position of the equator have
disappeared, especially since the wide separation greatly lessens the
chances of securing both in the same section. For this reason all
figures of stages after this period are drawn from only one of the
daughter nuclei. After the spindles have broken in two, the telo-
phases are very inconspicuous objects; though they stain deeply, the
chromatin is concentrated into so narrow a space that they are
practically invisible under any but the highest power (figs. 23, 35)-
The aster
As previously reported by Stevens, Kusano, and myself, there
are no granules, radiations, condensations, or any other indications
of the presence of centrosomes at the poles of the spindle during
prophase or metaphase. But about the time the two halves of the
spindle separate, radiations begin to emanate from the chromatic
masses. At first so delicate as to be on the very limit of visibility,
the aster rapidly increases in prominence until it becomes exceedingly
conspicuous, clearly visible under a magnification of forty or fifty
diameters. At first the radiations may appear to emanate from the
——S
"Se
lo eh we ee
is | os ale
1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 345:
center of the chromatic mass (figs. 24, 25), but very soon it is evident
that the focus is beyond the condensed chromosomes (fig. 24). AS
the rays increase in strength the focus is shifted, until there is a
considerable interval between the center and the chromatin (jig. 27).
In this stage, since the chromatin is condensed to its minimum
volume, the aster is so very much more prominent than the chromatin
that the latter is likely to be overlooked altogether, making it appear
that the cyst has no nuclei, but only asters! The chromatic mass
soon enlarges, however, and rounds off into the spherical karyosome
of the resting nucleus (figs. 27, 28). Up to this stage the chromatin
lies suspended in the cytoreticulum, without any apparent relation to it.
The appearance of the karyosome, however, marks the resumption
of definite relations of nucleus and cytoplasm in the formation of a
vacuole around the chromatin (fig. 28). This vacuole is at first
bounded only by the meshes of the cytoplasm, but soon the rays of
the aster bend around it and form the heavy nuclear membrane which
incloses it (figs. 29, 30), as previously described by KusANno (10) and
myself (4). When the nuclear membrane is complete, the aster
gradually disappears; the rays first become much more numerous and
finer; the center gradually becomes diffuse and stains less deeply
(fig. 4); and finally the aster is transformed into a condensation of
_ cytoplasm as previously described (figs. 31, 20, 3):
During the disappearance of the aster, however, the nucleus usually
enters into the prophases of the next division, so that only seldom is
4 cyst found where the nuclei are still in their vegetative condition
when the asters are in their last stages. On the other hand, it is not
at all unusual to find that the new spindle has already formed, before
the aster has disappeared, and in rare cases the anaphase of the suc-
ceeding division (fig. 20) may be reached before the old aster is com-
pletely gone. The disappearance of the aster probably occupies a
Period of somewhat definite length, while the rapidity with which
the mitoses succeed each other varies greatly in diferent cysts. 1
Was this lack of correspondence between the cycles of astral and
nuclear metamorphoses that made it necessary in the former paper
on this subject to state some conclusions provisionally that may now
be positively established. 3
From their function of forming the nuclear membrane, the asters
346 BOTANICAL GAZETTE [NOVEMBER
of Synchytrium have been named karyodermatoplasts by Kusano
(13). Although somewhat long, this term may be useful in alluding
to the junction of the asters, but there seem to be certain objections
to its use as the name of a structure. First, the structure so desig-
nated is so variable that it is difficult to define it. Sometimes the
_ aster is single, sometimes double or triple (fig. 2); sometimes it has
one clearly defined granule at the focus of the rays; more often there
are several such granules more or less eccentrically placed; or there
may be none at all. Sometimes there is an elongated band which
bears radiations all along its length, like the blepharoplast of a
cycad. It is evident that the term karyodermatoplast can be defined
only by its function, while such a term should rest on a morphological
basis. Second, though the aster, so far as observation has yet indi-
cated, serves only to reconstruct the nuclear membrane, that function
alone does not seem to the writer adequate to account for its enormous
development in Synchytrium. This is more apparent when one recalls
the fact that in heteroschizis and nuclear gemmation the membranes
of the daughter nuclei are formed without the intervention of any such
structure. I have preferred, therefore, in the present discussion to
employ the descriptive term aster for the structure in question, without
committing myself to its significance. The question of the radiate
structures in Synchytrium and their homology is one of very great
interest and deserves consideration in a separate paper.
The chromosome number
Inasmuch as most of the nuclei or their ancestors have been derived |
by amitosis, as has been previously shown, the determination of the
number of chromosomes in Synchytrium becomes a matter of much
more importance than in organisms where the orderly sequence of
mitosis has not been interrupted. On this account especial care has
been taken to insure accuracy of observation and interpretation.
Upward of 500 slides have been used in the study. Altogether several
hundred mitotic cysts with many thousands of individual spindles
have been observed. Of these only the most favorable were used for
basing the conclusions. The location of the cysts containing these
most favorable spindles was recorded by vernier readings of the
mechanical stage and filed in a card catalogue, so that they could be
Be. AP ee” ey
1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 347
reexamined in rapid succession as frequently as desired. The
favorable cysts so listed number about fifty; most of them contain
several hundred spindles.
All of the results obtained were not exactly concordant, but I shall
give the observations on which the conclusions were based that the
reader may be enabled to judge of their soundness for himself. In
all but two of these favorable cysts there were constantly four chromo-
somes. In these two, however, the number of chromatin bodies
was certainly more than four (fig. 42). But while the chromosomes
are all of the same size, some of these bodies were smaller than chromo-
somes and had the appearance of masses of chromatin from the late
spirem which had not yet fused together into the compact chromo-
somes of metaphase. Inasmuch as the spindles were undoubtedly
newly formed, this is probably the correct interpretation, especially
as there seemed to be in some cases faint wisps of spirem remaining
about the equator of the spindle. But whether these supernumerary
chromatin bodies are to be explained on some such basis or whether
they are actual irregularities in the number of chromosomes, I am
of the opinion that they do not seriously weaken the conclusion
that the chromosome number is four. Although it is unusual for a
Writer to state difficulties of this sort as frankly as has WILSON (20)
in his study of Metapodius, seeming discrepancies in the number
arising from one cause or another are, I believe, frequently met with
in efforts to count chromosomes.
In all of the other cysts studied there was no deviation from the
Constant number four. On all of the spindles the chromosomes were
Placed at angles of about go°, so that two, three, or four of them were
Visible, according to the angle of observation (figs. 14-19). In the
very much larger number of cysts whose spindles were not favorable
€nough to permit exact counting, there were no indications of a
different number. It should be noted also that four is an exceedingly
“asy number to count, for one can see four without counting them
One by one as is necessary for a larger number. In thus maintaining
@ Constant number of chromosomes the writer is supported by the
only other published accounts of the chromosomes of Synchytrium.
TEVENS in his paper on the primary mitosis (18) states (p. 413)
that “ they are probably four in number, although we do not assert
348 BOTANICAL GAZETTE [NOVEMBER
this with certainty,” and in his second paper he shows spindles with
the same number of chromosomes. KuUsANo (10) reports definitely
five chromosomes in S. puerariae.
The probability that the results thus obtained are accurate is very
greatly increased by the fact that in Synchytrium there is no differ-
entiation into soma and germ plasm. Every nucleus becomes either
directly or through its descendants the nucleus of a spore, which, if
successful in entering its host, becomes the large nucleus of a primary
cyst. Ifa variation of the chromosome number occurred at any point,
it would, on the individuality hypothesis, be perpetuated indefinitely,
affecting all the nuclei of later generations; whereas in the higher
plants and animals a variation in the somatic nuclei would be lost with
the death of the individual organism in which it occurred. It is clear,
therefore, that if a variation in the number of chromosomes should
occur only once in the repeated direct divisions through which the
nuclei of the spores have been derived, it would affect all the nuclei of
the next generation. Thus, though the nuclei of the later stages of
the parasite are so small that an irregularity in the chromosome
number might not be detected, yet in the large nuclei of the succeeding
generation it could not escape observation. Amitosis plays $0
important a part in the formation of the nuclei that if chromosome
variations occurred in only one per cent. of the direct divisions, the
nuclei of the whole parasite would in the course of a few generations
become so irregular that it would be impossible to recognize the
original number of chromosomes when it did occur. It may also be
remarked that an irregular reduction in the number of chromosomes,
such as might be expected ‘in the amitoses of a non-sexual organism
like Synchytrium, could lead, when repeated in indefinite series, t©
only one result—all the nuclei would finally have only one chromo-
some.
On the individuality of the chromosomes
Modern cytology may be almost said to be built around the theory
of the individuality of the chromosomes, and certainly no other
hypothesis has borne so much fruit in valuable results as this.
Without it the complicated process of mitosis would seem to lack
significance, and the doubling and reducing of the chromosomes in
=a ui a eal tha a
1909] GRIGGS—MITOSIS IN SYNCHYFRIUM 349
fertilization and reduction would be well-nigh meaningless. For its
_ support it has had, besides the constancy of the chromosomes in the
species, various observations on nuclei which were known to contain
either more or less than the normal number of chromosomes.
The great difficulty in the way of the theory has always been that
the chromosomes apparently lose their individual existence during
the vegetative phases of the nucleus. In many cases where the nuclei
are rapidly dividing the chromosomes do not, however, entirely lose
their individuality between the successive divisions, but divide and
reproduce themselves directly from the compact condition of mitosis.
These cases have been the evidence by which the vegetative period
of the nucleus was bridged over by the individuality hypothesis, for
there is an unbroken series of intergradations from this condition to
that in which the chromosomes have completely lost their morpho-
logical identity, and one would not suppose that nuclei in one condi-
tion differed fundamentally from those in the other. Accordingly,
basing their statements on observations of nuclei in which the indi-
vidual chromosomes could be traced, with more or less certainty,
from mitosis to mitosis, several writers have asserted confidently that
the individuality of the chromosomes is maintained through all con-
ditions of the chromatin, whether visible or not.
But the transformations of a set of chromosomes which, after
they are once formed, persist and divide are not necessarily equivalent
to the formation of a new set from a diffuse reticulum. If the chro-
matin reticulum gave rise only to the chromosomes, the analogy might
be closer; but when, as frequently happens, large amounts of chro-
matin are cast out into the cytoplasm as nucleoli, microsomes, or in
Mass, it is evident that the succeeding differentiation of the chromo-
somes involves factors different from those entering into the mere
transformation of a chromosome which persists intact through what-
ver metamorphoses it may pass. This may be illustrated perhaps
y comparing the chromosomes to metal rods which remain distinct
from each other when cold, but as the temperature approaches the
melting point become soft, lose their shape, and partially fuse together,
though each retains its distinctness and can be reclaimed unchanged
°n cooling. But after they have once melted together, all this is
changed, and they can be regained from the homogeneous flux only by
350 BOTANICAL GAZETTE [NOVEMBER
making them entirely over again. It seems quite possible that in the
diffuse vegetative reticulum the chromosomes are as completely fused
as the molten metal, and until we know more than we do now con-
cerning the nature of the reticulum, this alternative possibility should
be kept before us. The analogy of the molten metal is more suggest-
ive in cases like Synchytrium, where the chromatin is partially or
completely concentrated in a karyosome from which part or all of
the spirem is directly derived. Although cytologists have as a rule
paid but little attention to their behavior in mitosis (cf. WAGER 19),
such structures are common occurrences in many plants and animals.
If we may infer safely, as I believe we may, that the chromosomes
of Synchytrium decipiens number constantly four, it becomes a matter
of primary interest to determine how that constant number is main-
tained in all of the amitoses through which the nuclei pass. It has
long been assumed that the principal if not indeed the sole function
of the complicated process of mitosis was to insure exactly equal
division of the chromatin between the daughter nuclei. In view of the
fact, however, that the majority of the nuclei of Synchytrium are
derived by some form of amitosis either directly or through their
ancestors, and yet maintain the number of their chromosomes con-
stant, it is evident that mitosis is not necessary to maintain this
number.
The possibilities of an exact mechanical division of the chromatin
are somewhat different in the different varieties of amitosis. In
heteroschizis there occurs a metamorphosis of the nucleus suggestive
of that of mitosis. In the loss of the nuclear membrane and the
apparent cessation of interaction between the nucleus and the cyto-
plasm there may be a pause during which the chromatin is divided
granule by granule in such a way that the karyosomes of the daughter
nuclei are furnished with exactly equal chromatin content, just as is
visibly accomplished by the fission of the chromatin granules or the
chromosomes in mitosis.
Likewise it is not inconceivable that the karyosome may be divided
in a similar manner when it is broken up preparatory to nuclear
gemmation, though in this variety of amitosis there is no loss of the
nuclear membrane or other indication of a pause in metabolism.
An exact equational division of the chromatin under such circum-
1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 351
stances would be something of a novelty, but it would not necessarily
involve functions of the chromatin differing fundamentally from some
with which we are more familiar. Whenever the chromatin is with-
drawn granule by granule from a karyosome (nucleolus) preparatory
to mitosis, we must suppose, on the individuality hypothesis, that the
granules come out of the nucleus as they went in, properly sorted, so
that each granule is taken into that chromosome from which it came.
On the assumption of an equational division in heteroschizis and
nuclear gemmation, we should have to assume, in addition to this
well-known property of the chromatin granules to sort themselves out -
from the apparently homogeneous mass of chromatin of the karyo-
some, only the further property of reproducing themselves while yet
within the karyosome as they ordinarily do in the spirem. This is
perhaps not too much to ascribe to the chromatin, but even such an
addition to our theory would add a very large field for speculation
where the conclusions, with our present methods, could never be
checked by observation.
But when nuclear gemmation takes place in spirem two alternative
Possibilities are presented, the choice between which depends on the
nature of the spirem involved. If the spirem is an entirely different
Structure from the mitotic spirem, it would be rational to suppose
that each small karyosome, i. e., each granule of the spirem in nuclei
Such as fig. 37, contains four chromosomes derived by an equational
division of the mother karyosome as in the previous cases. But if the
amitotic spirem is like the mitotic, the situation is entirely different,
for we know from its later history the composition of the mitotic
spirem. It contains altogether only four chromosomes, which are
arranged serially, and any small part will contain chromatin from
only one chromosome, if a small part of such a spirem is extruded
and forms an independent nucleus. Therefore, it is evident that
ts chromatin is derived not from all four but from only one chromo-
Some. It is then a matter of great importance to determine the con-
Stitution of the spirem, but unfortunately, as stated above, the evidence
on this point is somewhat ambiguous, and a definite decision in favor
of either alternative seems impossible.
Certain features of nuclei dividing by constriction, however, seem
'0 throw some light on this matter. When amitosis by constriction
352 BOTANICAL GAZETTE [NOVEMBER
occurs, the nucleus develops lobes and divides up into a number of
daughter nuclei varying from two to a dozen or even more (jig. 41, 4, ¢).
One cannot tell by observation whether a nucleus is about to divide
into two or many daughters, for there is no apparent segregation of
chromatin into parts corresponding in number with the number of
small nuclei to be formed. Nor are the small nuclei necessarily
equal in size or chromatin content. Sometimes the variations are very
great; thus fig. 36 shows a cyst in which the primary nucleus has
divided, leaving the nucleolus undivided in one of the daughters,
while the other and smaller daughter nucleus has constricted or
budded again to form a relatively minute nucleus at one side. It is
difficult to believe that these three nuclei had their origin in equational
divisions of the chromatin previous to the actual constriction of the
mother nuclei. All appearances go to indicate rather that the factors ©
controlling the division of these nuclei are entirely disconnected from
the behavior of the chromatin, and favor CHILp’s hypothesis (2) that
amitosis is merely a physical process. But whether this be the case
or not, nuclei so formed are normal and sometimes pass into mitosis.
When this happens they show the four chromosomes characteristic of
the species (fig. 35, a). More commonly, however, amitosis by con-
striction is but an incident in the division of the chromatin, for the
constricted nuclei are soon completely converted into groups of small
nuclei by gemmation (see 6, fig. 3). Since the constitution of these
nuclei is of great importance in this connection, I have introduced
here a series of three drawings of nuclei from the same cyst. Fig.
38 shows a case of amitosis of the type most commonly observed,
though it is not common in Synchytrium; in jig. 39 the two nuclei
are completely separated but still touch each other; in fig. 4°
one of the granules similar to those on the periphery of the other
nuclei has formed a small nucleus by gemmation. The individuality
hypothesis leads us to rather startling conclusions regarding the con-
stitution of these nuclei. Each of the large nuclei must have four
chromosomes. And since each of the granules on the periphery as
the power of organizing a new small nucleus with four chromosomes;
it also, if the chromosomes have a material continuity from generation
to generation, must contain four chromosomes. In other words, the
large nuclei must at one and the same time have four and 74 chromo”
1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 353
somes. In these nuclei the small karyosomes number 4, 5, 6, 7.
The respective nuclei must therefore have 16, 20, 24, 28 chromosomes,
and still have no more than four!
There seems to be no option but to conclude that in Synchytrium
there is no morphological continuity of the individual chromosomes,
nor is there any definite set of chromatin granules of whatever size
which are passed on intact from nucleus-to nucleus. The number of
chromosomes seems to be a physiological rather than a morphological
constant. Not the chromosome but the nucleus itself seems to be
the morphological unit of the lowest order. Apparently any mass of
chromatin that is capable of organizing a nucleus at all, i.e., any
particle of nuclear matter that is able to continue life and reproduce
itself, whether it originally contained portions of all of the chromo-
somes or of only one of them, will preserve the characteristic number
of chromosomes along with the other hereditary characters of the
species. “
Although such a hypothesis seems to be required to explain the
phenomena of nuclear division in Synchytrium, it would not be wise
to attempt to reach any decision as to its general applicability at. this
time. In proposing it to account for these features of Synchytrium,
the writer is not at all oblivious of the enormous amount of evidence
which has been heaped up in recent years in support of the individu-
ality of the chromosomes. The occurrence of protochromosomes in
the nuclei of many cells (OVERTON 14); the persistence of super-
numerary chromosomes in cases of polyspermy, etc.; and the remark-
able size and shape differences among the individual chromosomes
such as have been discovered in animals, notably by McCiunc and
Montcomery, and recently in plants by SCHAFFNER (15) and Miss
Hype (9), along with many other observations of a similar nature,
are facts which give very great weight to the hypothesis of the indi-
Viduality of the chromosomes. Nevertheless, it must be remembered
that almost all of the evidence in favor of the individuality hypothesis
is of Suggestive rather than demonstrative value. This was clearly
recognized by all observers until about five years ago, but since that
ime the amount of such evidence has increased to such an extent that
Cytologists have been much less cautious than before in using the
hypothesis. The renaissance of MENDEL’s law so favored the general
354 BOTANICAL GAZETTE [NOVEMBER
acceptance of the chromosome hypothesis by making it highly desir-
able on theoretical grounds to find the material bearers of hereditary
units which the law seemed to demand, that practically all opposition
to it was swept away, and it has come to be the groundwork on which
present-day cytology has been constructed. If then the basis on
which the theory rests is in any degree unproven, it is well for cytolo-
gists to keep that fact clearly before them, that they may be guarded
against making any false steps in blind adherence to an insecure
hypothesis or of failing to notice any evidence which might throw
doubt on the validity of their theory.
The writer for his own part, however, has no intention of discard-
ing the whole hypothesis of chromosome individuality on the basis
of these observations on Synchytrium, or on the similar results
obtained by CuiLp (2) from studies of representatives of nearly all
the great animal phyla. The conflict of evidence for and against the
hypothesis seems clearly to require us to keep the case open for the
present. It is as tending to promote such a judicial attitude of sus-
pended judgment among cytologists rather than as overthrowing the
whole theory that the writer would have his results received.
Summary
The mitoses are all of the same type and occur simultaneously
throughout the cyst.
The spirems of amitosis are frequently indistinguishable from those
of mitosis.
The spindle is of the oomycete type, without centrosomes.
The asters first appear as emanations from the condensed chro-
matic mass of telophase, but quickly separate from the chromatin
and their rays form the nuclear membrane. »
The number of chromosomes is constantly four. ;
In some sorts of amitosis an equational division of the chromatin
previous to the division of the nucleus is possible, though there is no
evidence of such a process.
In other varieties of amitosis an equational division of the chro:
matin does not seem to be possible, but rather direct division gives
some indication of being merely a physical process as suggested by
CHILD.
Igo9| GRIGGS—MITOSIS IN SYNCHYTRIUM 355
Nevertheless, nuclei known to be derived by amitosis show four
chromosomes.
It is therefore concluded that in Synchytrium there is no morpho-
logical or material continuity of the chromosomes from generation to
generation of nuclei; but that the chromosome number is a physio-
logical constant, like the other hereditary characters of the species.
CoLtumMBus, OHIO
Addendum
After the foregoing paper had been completed and submitted for
publication, Kusano’s “Contribution to the cytology of Synchytrium
and its hosts’? (Bull. Col. Agr. Imp. Univ. Toyko 8: 80-147. pls.
8-II. 1909) reached me. KUSANO’S paper, for the most part, is
based on observations of S. puerariae, which seems to be remarkably
similar to S. decipiens, which he also used for comparison. He gives
much space to the metamorphosis of the nucleolus (karyosome),
which is unusually favorable for study in Synchytrium, showing that
all the elements derived from the mother nucleus are concentrated
in the karyosome of the daughter nucleus from which they are later
withdrawn. He-figures the prophases and metaphases of the primary
mitosis, confirming for the most part STEVENS’ observations, but like
him failing to find the anaphases and telophases, which for some
reason seem to be very difficult to observe. He then devotes con-
siderable space to the secondary mitoses, obtaining results similar
'o those of the present paper; but his account of the prophases differs
Considerably from that of the present writer. His series of figures,
however, is not complete at this stage, and he admits (p. 102) that he
had not been able to follow the formation of either the chromosomes
or the spindle. Again, in the telophase there is a wide gap between
his figs. 55 and 56, during which the aster is developed, a process
about which he was left to conjecture (p. 127), incorrectly supposing
that it originates from the cytoplasm. In addition to the method
of segmentation by cleavage furrows described by HARPER, he reports
4 second method in which the sporangium walls are precipitated by
the cytoplasm as in the endosperm of the higher plants. This form
of segmentation occurs also in S. decipiens and, according to my
observation, is more common than that described by HARPER.
356 BOTANICAL GAZETTE [NOVEMBER
KusANno saw and figured the clusters of small nuclei due to various
sorts of amitosis as described in my former paper (5), but he did not
study them carefully and failed to ascribe to them the importance
that they really possess. He repeats the statement of his preliminary
paper that the chromosomes number constantly five, and thus adds
strongly to the case against the individuality of the chromosomes
made in the present paper.
LITERATURE CITED
1. CHAMBERLAIN, C. J., The ovule and female gametophyte of Dioon. Bor.
GAZETTE 42: 321-358. 1906.
. CHILD, C. M. — as a factor in normal and regulatory growth. Anat.
Anzeig. 30:271-297. 1907.
. Davis, B. M., Oogenesis in Saprolegnia. Bor. GAZETTE 35:233-249;
320-349. 1903.
. Griccs, R. F., On the cytology of Synchytrium. III. The réle of the centro-
somes in the foroattens of the nuclear membrane. Ohio Nat. 8:277-286.
8
N
w
>
5: , Some aspects of amitosis in Synchytrium. Bort. GAZETTE 47?127-
138. 1909.
6. , A note on amitosis by constriction in Synchytrium. Ohio Nat.
9:513-515- 1900.
. GUTTENBERG, H. R. von, —— Studien an Synchytrium Gallen.
Jahrb. Wiss. Bot. 46: 453-477. 1909.
- Harper, R. A., Sexual Beardie and organization of the sitio in
certain mildews. Carnegie Inst. Pub. No. 37. 1905.
9. Hype, Eprru, The reduction division in the anthers of Hyacinthus orientalis.
Ohio Nat. 9:539-544. 1909.
- Kusano, S., On the nucleus of Synchytrium puerariae Miyabe. Bot. Mag.
Tokyo 21: 218. 1907.
, On the cytology of Synchytrium. Centralbl. Bakt. 197:538. 19°7-
, On a disease caused by Synchytrium puerariae. Bot. Mag. Tokyo
22:1. ae
13. , On the “karyodermatoplast,” a nuclear-membrane-forming body.
Bot. Mag. Tokyo 22:205, 206. 1908 (in Japanese without figures).
14. OvERTON, J. B., On the organization of the nuclei in the pollen mother cells
of certain slants with especial reference to the permanence of the chromo-
somes. Annals of Botany 23: 19-62.
- SCHAFFNER, JOHN H., The reduction division in the microsporocytes of Agave
virginica. Bor. Gareres 47:198-214. 1909.
. STEVENS, F. L., The compound oosphere of Albugo bliti. Bot. GAZETTE
29:149~176, 225-245. 1899.
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-
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1909] GRIGGS—MITOSIS IN SYNCHYTRIUM 357
17. STEVENS, F. L., Some remarkable nuclear structures in Synchytrium.
Ann, Myc. gtallocgile ie
18. STEVENS, F. L. anp A. C., Mitosis in the primary nucleus of Synchytrium
decipiens. Bor. GAZETTE 28: 2405-415. 1903.
19. WAGER, HAROLD, The nucleolus and nuclear division in the root apex of
Phaseolus. Annals of Botany 18:39-53. 1904
20. WILson, E. B., Studies on chromosomes. V. The chromosomes of Meta-
podius. A contribution to the hypothesis of the genetic continuity of the
chromosomes. Jour. Exp. Zool. 6:147-205. 1909.
21. YAMANOUCHI, SHIGEO, Mitosis in Fucus. Bor. GAZETTE 47:173-197.
Igog.
EXPLANATION OF PLATES XVI-XVIII
All the figures were made with a 1.5™™ immersion objective and ocular 12
giving a magnification of 2130, excepting fig. 36, which was drawn under a 4™™
dry lens with a magnification of 400. hey were reduced 4 in reproduction, can-
celing the enlargement due to the camera and rendering them the same size as
they were seen in the microscope.
PLATE XV1
Fic, 1.—A vegetative nucleus.
Fics. 2-4.—Three stages in the formation of the spirem from the same cyst,
showing also the asters of the preceding division in process of disintegration.
Fic. 5.—A large nucleus in spirem beside which is a small nucleus, derived by
gemmation, still in the vegetative condition; from the same cyst as jigs. 6-9 and 13.
Fics. 6-9.—The development of the spindle, from the same cyst.
Fics. 10-12.—The contraction of the spirem around the equator of the spindle;
nuclear een with its chromatic granules dissolving; from the same cyst.
Fic, 13.—A young spindle with the chromatin so densely aggregated around
the es that different parts cannot be made out; from the same cyst as jigs.
5-9.
Fic. 14.—A spindle at metaphase, showing three of the four chromosomes.
Fic. 15.—Chromosomes enlarging as they divide, each of them attached to
the pole by heavy fibers.
IG. 16.—A polar view of metaphase, showing the four chromosomes and
the nucleolus.
1G. 17.—Chromosomes divided and beginning to separate
Fic. 18.—Anaphase, showing separating chromosomes andthe heavy fibers
Which connect them across the equator of the spindle; from the same cyst as
figs. I ee
IG. 19.—Anaphase; chromosomes lost in the deeply staining mass at the
Poles; pinot fibers prominent.
PLATE XVII
Fic 20.—Anaphase similar to fig. 19, but remarkable for the very late persist-
ence of the aster from the previous division.
358 BOTANICAL GAZETTE [NOVEMBER
Fic. 21.—Similar anaphase, with the aster appearing unusually early.
Fic. 22.—Connecting fibers withdrawn ;
Fic. 23.—Spindle breaking apart in the middle.
Fic. 24.—Radiations from the chromatic mass just beginning to appear at
the lower pole; at the upper pole the focus has shifted out beyond the chromatin.
Fic. 25.—A stage in the development of the aster intermediate between the
two poles of the spindle shown in jig. 24
Fic. 26.—Aster strongly developed, weiile the chromatin remains extremely
closely condensed; from the same cyst as jig. 24.
Fic. 27.—Chromatin beginning to enlarge to form karyosome.
Fic. 28.—Karyosome rounded off; nuclear vacuole just appearin
1G. 29.—Rays of aster beginning to bend around the vacuole to heat nuclear
membrane; nucleolus and remnant of spindle lying below daughter nucleus.
1G. 30.—Rays of aster nearly surrounding the nuclear cavity; karyosome
passing into spirem of the next mitosis; cf. fig. 2
Fic. 31.—A vegetative nucleus with the old ster lying along side.
PLATE XVIII
Fic. 32 Seine of a primary nucleus with halo and disintegrating nucleolus.
1G. 33.—T wo sporangia from a newly segmented summer sorus, showing
the character of the mitoses and the independence of the segments.
1G. 34.—A spindle of one of the last mitoses of the sporangia.
Fic. 35.—a, group of spindles formed by the division of a cluster of nuclei
formed by amitosis, which lies in the center of a large cyst, the periphery of which
contains the spindles of many small nuclei (b) derived by gemmation.
Fic. 36.—Amitosis by constriction in a primary cyst, showing very great
differences in chromatin content of daughter nuclei.
Fic. 37.—An amitotic spirem in preparation for nuclear gemmation
Fics. 38-40.—Amitosis by constriction and by nuclear gecuanation in the
same Sis
G. 41.—a, two amitotic nuclei; 6, an adjacent nucleus in spirem, which
ee undoubtedly amitotic resembles mitotic spirems of figs. 4, 6; ¢ @ cluster
of amitotic nuclei from the same section. :
1G. 42.—A spindle with five chromatin bodies, presumably chromatin
granules of the spirem not yet fused into chromosomes; cf. fig. II.
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GRIGGS on SYNCHYTRIUM
BOTANICAI. GAZETTE, XLVIII
PLATE XVII
BOTANICAL GAZETTE, XLVIII
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INFLUENCE OF ELECTRICITY ON MICRO-
ORGANISMS
GEORGE E. STONE
(WITH TWO FIGURES)
The influence of electricity on the higher plants has been studied
for many years, and there is considerable literature pertaining to this
subject. The writer has carried on investigations in this line for
many years, and some of the results have been published from time
to time.
Little or no attention, so far as we know, has been given to the
study of the influence of electricity on the growth and multiplication
of microorganisms, and it is our purpose to present in this paper the
results of some of our investigations of the past two or three years.
Microorganisms are favorable types with which to experiment,
since they respond very quickly to stimuli, and, as might be expected,
the results are more pronounced than is the case with the higher plants,
where growth is relatively slower. The investigations given in this
Paper were made on microorganisms common to water, milk, and
soils, and some experiments were made with yeast. In some instances
the natural flora common to water, milk, soils, etc., was used, and in
others we experimented with pure cultures.
Influence of electricity on bacteria in water
Our first experiments with the influence of electricity on micro-
Organisms were undertaken in connection with those common to
water, and were designed with the object of rendering stagnant water
more wholesome by a system of electrical treatment. Our studies
had not extended very far, however, before we found that, instead
of being decreased by means of this treatment, the bacteria increased
€normously, especially when weak currents were employed. In this
series we made use of the natural bacterial flora of water, while in
others isolated species were experimented with. The experiments
Were made in glass jars, in some cases those of rectangular form being
used, and in others a wide-mouthed bottle. For the purpose of
Measuring currents we made use of a Weston milliammeter and the
359) [Botanical Gazette, vol. 48
360 BOTANICAL GAZETTE [NOVEMBER
usual bacterial methods were employed throughout these tests. All
platings were made in Petri dishes in standard agar-agar, and the usual
dilution methods were followed. The agar cultures were incubated
at the usual temperatures, but the experiments were conducted at
room temperatures in most cases, which ranged from 60° to 70° F."
TABLE I
Showing the influence of electrical stimulation (galvanic currents) on the bacteria
in water. First cultures made 24 hours after treatment.
NUMBER OF BACTERIA IN 1°°
DATE OF MAKING
ULTURE
Normal | Trested
June TO Vis fas GA0Z 43,642
BO es 3435 108,785
The experiment shown in the preceding table was made with
two rectangular jars with approximately
the following interior dimensions: height
16°™, width 12°™, diameter 4°™. These
jars were filled with water obtained from
a pond contaminated to a greater or less
extent with sewerage. One was a normal
or untreated jar, and the other contained
electrodes composed of copper and zinc
respectively, which were connected with
wires and generated a current. The
electrodes were of the same diameter
as the jar, and one was placed in each
end. A jar of this type constitutes 4
galvanic element (water cell), although
the strength of current produced in this
Fic. 1.—Jar, ieondal with case is very weak, averaging about 0.1
cotton ohag and copper and zinc milliamperes. Samples of the water were
electrodes, used i in electrical ex- plated i in agar-agar 24 hours after treat-
periments with milk and water. ment. On the second day, however, the
experiment was discontinued. The results given in table I show
In carrying on these experiments the writer is under special obligation to Mr.
N. F. Monanan, a former assistant in our laboratory, who supervised most of
details of the work.
Ig09] STON E—ELECTRICITY AND MICROORGANISMS 361
considerable increase in the number of bacteria in water resulting
from electrical stimulation.
The number of organisms in the electrically treated jar increased
from about 3000 to 43,000 on the first day, and to 108,000 on the
second day.
TABLE II
Showing the influence of electrical stimulation (galvanic currents) on Pseudomonas
radicicola. First cultures made 24 hours after treatment.
NUMBER OF BACTERIA IN 1°
DaTE OF MAKING
CULTURE
Normal Electrical
January 23.... 6,000 15,000
anuary 24 50,893 3,178,246
January 27 52,741 4,287,002
January 31 50,217 5,210,112
February 4 50,217
February 8 42,112 10,200
February 12... 41,110 50,000
February 16... 35,000 4,000
TABLE Ii
Showing the influence of electrical stimulation (galvanic currents) on Bacillus
megaterium DeBary. First cultures made 24 hours after treatment.
NUMBER OF BACTERIA IN 1°
DATE OF MAKING :
CULTURE .
Normal Electrical
February 25 ... II,000 243,000
February 28 .. 21,000 3,462,000
March 4.42. 25,400 600,
Maren 67 p5. 20,000 4,566,400
March 12.2. 32,000 »950,
March 165.451. 10,000 243,000
atch aa ass, 35,000 500,000
March 24...... 2, 22,000
The experiments given in the preceding tables were made in wide-
mouthed jars approximately 10°™ in diameter and 21°™ high (fig. 1).
Those containing the electrically treated water were provided with
electrodes made of copper and zinc, which were connected with a wire
as in the last experiment. The electrodes were about 4°" wide and
long enough to extend over the lip of the bottle. The strength of
Current developed in this galvanic cell was about 0.3 milliamperes,
and it remained very constant throughout the experiments. The
362 BOTANICAL GAZETTE [NOVEMBER
jars in every case were provided with cotton plugs and the whole
outfit was sterilized before using. In these experiments pure cultures
were used, and the medium, in this case water, was also sterilized
before being inoculated. In one series (table II) the jar was inocu-
lated with Pseudomonas radicicola (Beyerinck) Moore, from alfalfa;
while in the experiments shown in table III the jar was inoculated
with Bacillus megaterium DeBary, 1°° of a liquid culture medium
being used to inoculate the jarsineachcase. Special care was taken to
inoculate the normal and treated jars with the same number of organ-
isms. An examination of the tables II and III will show that there
was a marked increase in the number of bacteria during the first
few days asa result of electrical stimulation. The maximum in one
case was 52,000 for the normal and 5,000,000 for the treated; in
another case 32,000 for the normal and 7,000,000 for the treated. It
will be noted that the subsequent decrease in the number of the
organisms was very marked in the electrically stimulated cultures, a
feature due to the accumulation of zinc oxid in the jar, which is
always present as a white precipitate in galvanic cells of this type-
The presence of zinc oxid in water formed by the action of even com-
paratively weak currents is toxic to bacteria, and the same toxic
effect is well illustrated in galvanotropic experiments with roots.
Some of our experiments which were made in much smaller jars failed
entirely, as the smaller volume of water employed became concentrated
so quickly with this substance that a toxic effect on the organism
occurred very shortly after inoculation. Some of the precipitate
obtained was dried and dissolved in flasks containing sterilized water.
The jars were then inoculated with Bacillus megaterium DeBary,
with the result that very little increase in the number of bacteria
occurred where a 2 per cent. solution of this prepared precipitate of
zinc oxid was used, and a 10 per cent. solution apparently killed
all bacteria. In both of the experiments enumerated there occurred
a slight falling-off in the number of organisms in the normal or
untreated cultures. This is of common occurrence, however, in
standing water, or even in soils under certain conditions.
The strength of current developed in these experiments (0-1 and
o.3 milliampere) was very constant, and from the results obtained it
is evident that it acted as a marked stimulus. A large series of
1909] STONE—ELECTRICITY AND MICROORGANISMS 363
experiments made by us on the higher plants has shown that this
current strength is very close to the optimum, and in all probability
the optimum current strength for bacteria would differ little if any
from that of the higher plants. We have employed this method of
electrically stimulating bacteria and have enormously increased the
number of organisms in cultures containing the legume Pseudomonas,
which is used in inoculating soils.
Some experiments were also carried on at the same time relative
to the influence which electrical stimulation might have upon nitrogen
fixation, but the results are incomplete and will not be given in this
paper.
The influence of electricity on bacteria in milk
The purpose of our experiments in this series was similar to that
in the experiments made with water; that is, to determine the effect
of electrical stimulation on the microorganisms in milk. Our object,
however, was not only to ascertain the effects of optimum currents, or
at least those approximating the optimum on the bacteria of milk,
but to observe the effects of strong electrical charges.
Milk constitutes an excellent medium for the multiplication of
bacteria and is well suited in some respects to experiments of this
Mature. The experiments given in tables IV and V were conducted
Similarly to the ones shown in the preceding series; that is, the bacteria
Were stimulated by galvanic currents and the same size culture jars
were used (jig. 1). About 1.5 pints of unsterilized milk were placed
in each jar and a milliammeter indicated the strength of current to
be approximately o.3 milliampere in the electrically treated samples.
The jars were provided with cotton plugs and were sterilized before
being filled with milk. The usual dilution methods were followed
and the standard agar-agar was used for plate cultures. In practically
all instances the counts are averages of three and four plates. Plat-
ings were made of the milk at the beginning of the experiment, that
is, before being electrically stimulated; therefore these counts, which
are averages, answer for both the treated and untreated cultures.
The results of electrical stimulation on bacteria in milk are shown
In the experiments given in tables IV and V, but since milk sours
and curdles badly in a few days it was necessary to limit the duration
364 BOTANICAL GAZETTE [NOVEMBER
of the experiments. In the normal or untreated samples the increase
in the number of organisms in one experiment was from 143,000 to
6,000,000; while in the treated samples the number reached 94,000,-
ooo. In the experiment shown in table V the normal increased from
118,000 to 4,000,000; while the electrically treated reached 83,000,-
ooo. The results are more striking than those obtained by the treat-
ment of water, as might be expected, since there was more food avail-
able for the use of the organisms in the latter series.
TABLE IV
Showing the influence of electricity (galvanic currents) on the bacteria in milk
NUMBER OF BACTERIA IN rCC
DATE OF MAKING
CULTURE
Normal Electrical
May 10,2 BoM ws s.o. 143,395 143,395
May 17,-9 ALM; 345 Ss. 809,112 3,874,421
May 19,5 P.M es 54 1,470,441 86,592,600
May 18,9 A. M....... 6,082,542* 94,851,806*
* Milk sour.
TABLE V
Showing the influence of electricity (galvanic currents) on the bacteria of milk
NUMBER OF BACTERIA IN 1CC
DATE OF MAKING 2
CULTURE
Normal Electrical
May 17, 10 A.M...... 118,542 118,542
May 31955 PioMs ok. 678,333 1,848,806
May 18, Io A.M...... 1,026,533 41,778,766
May 18, 5 P.M....... 4,591,500* 83,363,866*
* Milk sour.
Another series of experiments was undertaken to demonstrate the
effects of static electricity on bacteria in milk. For this purpose We
employed a static machine of the Tépler-Holtz type, which was
designed for X-ray work and is capable of producing a spark six
inches or more in length. The method of plating, etc., was the same
as has been previously described, and the culture jars were of the
same type, except that the electrically stimulated jars were covered
with tinfoil in the same way as a Leyden jar. The copper and zinc
plates were dispensed with, of course, and the milk was charged
direct from the static machine. In this series three jars were used:
4
.
j
1909] STONE—ELECTRICITY AND MICROORGANISMS 365
one normal, one treated with positive, and one with negative charges. —
The milk in the electrically treated jars was charged with sparks from
a static machine in the same way that a Leyden jar is charged, an
electroscope being used to determine the nature of the charge. In
the milk experiments which follow it should be pointed out that the
charges varied considerably.
TABLE VI
Showing the influence of static electricity (positive and negative charges) upon the
bacteria in milk. Electrical jars charged with one spark each June rr.
NUMBER OF BACTERIA IN 1CC
Date OF MAKING
ETI Electrical (positi Electrical (negative
Normal pais a oe Gata
1S are ane eee ee 8,342 9342 8,342
Wee 865s ee 69,000 196,300 ieee Gee
PUNE 920 ae 568,000 000 67,500
| 3S ee eee 1,213,000 16,432,500 19,374,600 /
Bete tes ee 9,876,400 0,500,000 000,000
ne Sa ae ee 27,432,000 153,461,000 be ane te
Se ee oe 190,500,000* 267,000,000* 233;339;000
* Milk curdled.
TABLE VII
Showing the influence of static electricity (positive and negative charges) upon
the bacteria in milk. Electrical j jars charged with 1o sparks each June 2.
| NUMBER OF BACTERIA IN ICC
Date OF MAKING :
CULTURE Electrical (positive Electrical (negative
Normal - charge) charge)
nade BIO Aas ae 65,000 ove 565,000
une 2, 5 “ fie ape 73,0 597; 245333
June 3, 10 A. M 19,057,000 23,443,066 18,088,333
gene's, oP M5, 5. 107,440,000 151,510,000 I ee
June 4,10 A.M., 2 201,413,333* 287,380,000* 212,816,666
* Milk sour.
In the experiment shown in table VI one large spark was given
each electrically treated jar, one being given a positive and the other
4 negative charge, and in the one shown in table VII the number
of sparks was increased to 10. The electrical treatment, the results
of which are shown in table VI, where the milk was charged with a
Single spark and cultures made every 24 hours, gave rise to a decided
acceleration. This acceleration was perceptible at the time of the
366 BOTANICAL GAZETTE [NOVEMBER
first plating and continued throughout the experiments, which lasted
six days.
The results shown in table VII indicate that the treatment given
caused less acceleration. In this case platings were made at shorter
intervals. The first plating was made seven hours after stimulating;
at this time scarcely any acceleration was shown, which indicated
the possibility of the death of the organisms by treatment, while dur-
ing the same period the normal nearly doubled in the number of
bacteria. The later platings, however, made at 24, 31, and 48 hours
respectively after stimulation, showed a greater increase than that —
given by the normal, but the ten charges given in the latter experiment
were evidently too strong to obtain the optimum results. In both
the experiments enumerated (tables VI and VII) the milk was kept
on ice.
TABLE VIII
Showing the influence of static electricity (positive and negative charges) upon
the bacteria in milk. Electrical jars charged with 100 sparks each.
NUMBER OF BACTERIA IN ICC
DaTE OF MAKING
CULTURE : i
Electrical (positi Electrical (negative
Normal sy ctor iy é charge)
May 31, 10 A. M...... 528,000 528,000 528,000
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VOLUME XLVIII NUMBER 6
BOTANICAL (GAZETTE
DECEMBER 1909
DIOON SPINULOSUM !
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY I 31
CHARLES J. CHAMBERLAIN
(WITH. SEVEN FIGURES)
hice well-defined species of Dioon have been found in the Mexi-
can tropics: D. edule Lindl., D. spinulosum Dyer, and D. Purpusti
ose. LD, edule, which was described as early as 1843, is now quite
well known. Although D. Purpusii was described only a few months
ago, the species had often been seen, but had been mistaken for
D. edule, which it resembles in its general appearance. I was told
by a Mexican botanist that I should find D. edule along the Mexican
Southern R.R. in the neighborhood of Santa Catarina, State of
Oaxaca. He said there was no other cycad in that region. The —
3 plant was easily found, and I at once saw that it was a new species
intermediate between D. spinulosum and D. edule. The plant
called D. edule in fig. tor of WIELAND’s American fossil cycads is
the new D. Purpusii, as plainly indicated by the staminate cone and
_ by the leaves. MacDovucat and Rose collected cones of the new
_ Species in 1906 in the Tomellin cafion, where it was well shaded by
bushes and small trees. Purpus in 1908 collected seeds and bracts in
_ the Sierra Mixteca, Puebla. In April of the same year I saw the species
at various places between Santa Catarina and Tomellin, growing in
dry, exposed situations, associated with cactiand Beaucarnea. Rosk?
describes the staminate sporophylls as “bracts with recurved ovate
_ tips,” apparently supposing that the sporangia were borne on the
sdipee a prosecuted with the aid of a grant from the Botanical Society of
America
2 RosE, J. N., Studies of Mexican and Central American plants. Contrib, U. S.
Nat. Herb. 12: 259-302. 1909.
401
402 BOTANICAL GAZETTE [DECEMBER
adaxial surface, but of course they are on the under surface and the
tips point up instead of down. His description of “seeds about
4°™ in diameter” needs confirmation; 4°™ in length would be more
probable.
In general habit, in the straight, stiff, ascending leaves, D. Pur-
pusii resembles D. edule, and the leaflets have the texture of those of
D. edule, but they retain in some degree the spinulose character of those
of D. spinulosum. In the number of sporangia on a microsporo-
phyll, D. Purpusii is intermediate between D. spinulosum and D.
edule. The ovulate sporophyll is rather slender and tapers gradually
to a point, in this feature resembling D. edule and differing decidedly
from D. spinulosum.
Dioon spinulosum Dyer was described by E1cHLER’ in 1883,
the description being based upon a few leaves and a few trunks with-
out leaves. Since the largest leaf was only 65°™ in length, the plants
must have been very small. One of the trunks received by EICHLER
produced a leaf which his figure shows to be that of a plant only a
few years old. The material came from a nursery in Cordoba, State
of Vera Cruz, Mexico, and, according to the gardener, the plants grew
wild in the neighborhood of Tuxtla. The striking feature is the
spinulose leaf. No cones were found, and so EIcHLER remarks that
it might seem doubtful whether the plant is really a Dioon (“Es
méchte daher zweifelhaft erscheinen, ob die Pflanze wirklich ein
Dioon ist’’).
Dyer obtained a leaf from Yucatan, and since the locality was
given as Progreso, the leaf probably came from a cultivated specimen.
EICHLER agreed that Dyer should describe the new species. The
description, based upon the single leaf, is as follows:4
Folia breviter petiolata, elongato-lanceolata, rigida, plana, pinnatisecta, ad
3 pedes longa; segmentis circiter 70 utroque latere, mediis majoribus subop-
positis lineari-lanceolatis breviter acuminatis 18-23-nerviis, ad 4 pollices longis
media latitudine semipollicaribus, basi angustiore, utroque latere spinulis pun-
gentibus basim versus integerrimis, inferioribus in dentes palmatifidos desinenti-
bus. Sétrobili..... South Mexico, Tuxtla; Yucatan, Progreso. ae
Hoge). Herb. Kew.
3 EICHLER, A. W., Ein neues Dioon. Gartenflora 2:411-413-
883.
4 Dyer, W. T. iste Cycadaceae, in Biologia ee -Americana
Botany 3:190-195. 1882-18
1909] CHAMBERLAIN—DIOON SPINULOSUM 403
: During my second trip to Mexico, in 1906, I saw small specimens
of Dioon spinulosum in the park at Vera Cruz, but did not find it
growing wild. Gov. TEoporE A. DEeHEsA, of the State of Vera Cruz,
who has repeatedly assisted me in my investigation of Mexican cycads,
again used his influence in my behalf, and I am also under renewed
obligations to Mr. ALEXANDER M. Gaw, of the State Bureau of Infor-
mation, Jalapa, Mexico, for his continued interest and active coopera-
tion both in securing material and often in furnishing field notes.
Mr. Gaw found that the plants in the park at Vera Cruz came
from Tlacotalpam, a town southeast of Vera Cruz, and he also found
4 that most people do not distinguish the two species, D. edule and
_ D. spinulosum, for he was told that the plants in the park at Vera
: Cruz could be found growing wild in the vicinity of Tlacotalpam,
_ Catemaco, and elsewhere in the canton of Tuxtlas, and between
Palmar and Colorado on the Interoceanic R. R. Doubtless the infor-
mation in regard to the first three places was correct, but since I had
found only D. edule in the Palmar-Colorado region, Mr. GAw sent
a man through that entire district with a leaf of D. spinulosum as a
guide. The man found D. edule in abundance, but failed to find a
_ single specimen of D. spinulosum. In Vera Cruz the plant is called
__ palma de Dolores, the same name which in the Jalapa region is applied
to D. edule. The name tio tamal, which is commonly given to
_ D2. edule because the seeds are used in making éamales, does not
seem to be applied to D. spinulosum, although its seeds are edible.
_ The natives of the coast region call both the plant and the seeds
_ chicalitos, a name which I have not heard applied to D. edule.
_ Froma park in Tlacotalpam Mr. Gaw secured a large ovulate cone
of D. spinulosum, and he was told that the specimen came from the
Sierra de Oaxaca Mountains near Tuxtepec, where the plant was
Said to be very abundant. As the Tlacotalpam cone had only abortive
seeds, Mr. Gaw, after repeated efforts, succeeded in securing from
the Tuxtepec region an ovulate cone in which pollination and fertiliza-
_ tion had taken place. Later he secured a cone with ripe seeds, which
germinated readily. With the material Mr. Gaw sent the rather
Startling information that, according to the natives, the cones are
borne below the crown of leaves and not above the crown, as in D.
ed
404 BOTANICAL GAZETTE [DECEMBER
In March 1908 I visited southern Mexico to collect D. spinulosum.
While on the way to Tuxtepec, I was informed that a plant which
seemed to agree with my description, except that it was much taller,
could be found near Tierra Blanca. In the mountains west and a
little north of Tierra Blanca I found a few specimens and was told
that plants were more numerous a few miles farther south. The
information was correct, for on the immense hacienda of the Joliet
Tropical Plantation Company, a short distance from Tierra Blanca
and about 60 miles south of Vera Cruz, magnificent specimens are
abundant. Mr. J.C. DENNIs, superintendent of the plantation, very
generously furnished horses, guides, and the hospitality of his palatial
home while I explored the mountains and secured photographs and
material. The plant is usually well shaded, growing among the
prevailing limestone rocks which have given name (Tierra Blanca)
to the region.
From Tuxtepec, a town on the Papaloapam River about forty miles
southwest of Tierra Blanca, half a day’s ride on horseback brings one
to the mountains where D. spinulosum is as abundant as at Tierra
Blanca. In some places it is the only large plant, and it would not
bean exaggeration to speak of a Dioon forest. Beautiful specimens,
which might have been the pride of any conservatory, had been cut
down to get the cones, because it was easier to cut the tree than to
climb it. The natives use the young seeds in making éamales, as in
D. edule, and at a later stage the dry stony seed coat is a common
plaything for children. At Tuxtepec the dry seeds, each pierced with
two holes, sell for fifteen cents a dozen. The Indians said that the
plant extends some distance farther south, but that it does not occur
on the western (Oaxaca) side of the mountains.
Dioon spinulosum, with the exception of the Australian Cycas
media, is the tallest cycad known, and its slender trunk with a large
crown of leaves gives it the appearance of a palm (fig. 1). I measured
specimens 12™ in height, and Drs. BARNES and LAND, visiting
the Tierra Blanca region a few months after my return, found speci-
mens more than 16™ in height, almost as high as the tallest known
specimens of Cycas media. The slender trunk and graceful curve of
leaves are in striking contrast with the stocky trunk and straight, rigid,
ascending leaves of D. edule.
1909] CHAMBERLAIN—DIOON SPINULOSUM 405
1.—Dioon spinulosum on the et ae de Joliet near Tierra Blanca, March
Fic.
1908;_ the tallest plant is about 10™ in heig
- 406 BOTANICAL GAZETTE [DECEMBER
The ribbed surface of the trunk is due to successive crowns, and
affords some basis for an estimate of the age of the plant, but in the
lower part of the trunk of tall specimens the ribs may become too
obscure for accurate counting. The scars of the individual leaves,
which are so distinct in D. edule, are so obscure in D. spinulosum that
counting in the lower portion of large trunks is out of the question.
Whether the duration of the crown is two years, as in D. edule, I was
not able to determine, but assuming the duration to be two years,
the tallest specimens might not be more than 4oo years old. How-
ever, any estimate can be little more than a guess, until the duration
of crowns, and the effect of scale leaves, cones, and resting periods
upon the growth of the trunk have been studied much more carefully.
Still, I am inclined to believe that a 10™ specimen is no older than a
1™ specimen of D. edule.
At the base the trunk is much enlarged, often having twice as great
a diameter as it has o.5™ higher up. The roots are often exposed
for considerable distances, especially in precipitous places, where a
root may hang down along the surface of the rock. One root hanging
down in this way was exposed for a distance of more than 12™ and
was 5°™ in diameter where it again entered the soil.
Cutting through the trunk, which is not nearly so hard as that of
D. edule, it is seen that there is a single zone of wood surrounding the
large pith. The origin and development of the vascular cylinder, as
seen in embryos and young seedlings, is being studied by HELEN A.
Dorety.
Both EICHLER and Dyer gave accurate descriptions of the leaves
as they appear on small plants. E1cHter’s largest leaf (65° in
length) had 38 pinnae, the lowest of which were rudimentary. DvyER’S
leaf was about 1™ long, with 70 pinnae on each side. On plants 2™
or more in height the leaves reach their full size, so that leaves 2"
long, with 100 leaflets on each side, are not uncommon, while one leaf
measured 2.2™ in length and had 117 leaflets on each side, the leaflets
being 20°™ long and 1o™™ wide. There is great variation in the
leaflets, some only 14-15°™ long being 15™™ wide. ‘There are 5-8
sharp spines on each margin of the leaflets of large leaves. The
lower leaflets become more and more reduced, until the lowest ones
are nothing but spines, so that the leaf bears considerable resemblance
1909] CHAMBERLAIN—DIOON SPINULOSUM 407
to that of Encephalartos. The leaves of seedlings have comparatively
few leaflets, the first leaf sometimes having less than a dozen on each
side. It is interesting to note that in seedlings the leaves have no
reduced leaflets, even the lowest being as perfectly formed as those
in the middle of the leaf. The leaflets of seedlings have fewer spines
than those of older plants, there being only 2-6 on each margin. The
midrib is not so large as in D. edule and the leaves are much thinner.
A few leaflets of a leaf of medium size are shown in fig. 2.
Remembering that the natives had reported cones growing below
the crowns, one would naturally think of the condition in Bennettitales.
Fic. 2.—Portion of leaf of Dioon spinulosum from a specimen at Tlacotalpam;
X4; the cone shown in fig. 4 came from the same plant.
A glance at jig. 3 will show that the cone does hang down below the
crown. An examination of the apex of the stem shows, however,
that the cone is borne in the center of the crown as in D. edule, but
that a considerable elongation of the peduncle, together with the great
weight of the cone, causes the cone to bend over, slip between the
leaves, and thus hang below the crown. Consequently no seeds are
found in the nest of the crown as is so commonly the case in D. edule,
where the germination of seeds in this position often gives rise to
the appearance of branching. In D. spinulosum branching is rare.
Seedlings are found for a considerable distance around the large
ovulate plants. The natives say that at maturity the cone bursts
with a loud noise, scattering the seeds, or coyoles, the plant being
called coyolillo.
[DECEMBER
BOTANICAL GAZETTE
40
ew
“Os
\e | ANS
S/ % mG. 5 é asl pee
AM POG Fae
' te 81Ep
pee) hy,
Pana fee)
Fic. 3.—Dioon spinulosum with ovulate cone, on the Hacienda de Joliet, March
1908.
1909] CHAMBERLAIN—DIOON SPINULOSUM 409
The ovulate cone is
the largest yet known
for any gymnosperm.
In March, cones weigh-
ing 14 kilos were not
infrequent, and_ occa-
sionally a cone had
reached a weight of 15
kilos. Since the seeds
are not fully mature
until October, it is safe
to assume that the cones
increase somewhat in
weight after March, the
time of my visit. The
cone is cylindrical ovoid
(jig. 4), its general
habit distinguishing it
at once from the ovoid
cone of D. edule. It
reaches a length of 50°™
and a diameter of 27°”,
but the average cone
is about 20 per cent.
smaller than these meas-
urements.
The ovulate sporo-
phylls are very hairy,
as in D. edule and D.
Purpusii, but are much
more closely imbricated,
there being no_ pro-
jecting tips as is always
‘ Fic. 4.—Dioon spinulosum; ovulate cone from a
the case in the URES ee. ates at Tlacotalpam; x 4; November 1906.
of
D. edule and probably in D. Purpusii. In regard to the latter species,
however, my statement is based upon only a single sporophyll. The
410 BOTANICAL GAZETTE [DECEMBER
sporophyll of D. spinulosum is thick, fleshy, and rounded or obtuse
at the apex, contrasting again with the long tapering sporophylls of
D. edule and D. Purpusii. The contour of the exposed portion of
the sporophylls and the close imbrication is seen in fig. 4, especially
near the apex of the cone.
The seeds are white and perfectly smooth, but may become
slightly yellowish when mature; their length varies from 4 to 5.5°™
and the diameter from 2.5 to 3.5°™. Some of the ovules have the’
Fic. 5—Dioon spinulosum; dorsal Fic. 6.—Dioon spinulosum; ovulate
view of an ordinary sporophyll, the ovule sporophyll, from the cone shown in fig. 4,
on the left showing the false stalk; from with five ovules, three of which can be seen
a cone received from Tuxtepec, Apri on the left side, but only a portion of one of
1907. X#. the two on the right side is visible. X ?.
false stalk, characteristic of the genus, but it is not as frequent as in
D. edule (fig. 5). In one cone, with only abortive ovules, there were
frequently more than two ovules on a sporophyll, in some cases aS
many as five or six (fig. 6). Cycas, the most ancient genus of the
family, regularly produces more than two ovules on a sporophyll,
and in Dioon the production of more than two ovules is doubtless a
recurrence of the ancient habit. In rare cases, I have noted as many
as four ovules on the sporophylls of Zamia floridana and Ceratozamia
mexicana.
1909] CHAMBERLAIN—DIOON SPINULOSUM 411
As yet I have obtained only one staminate cone, and that not from
the field but from Professor TRELEASE, of the Missouri Botanical
Garden. Where the speci-
men came from could not
be determined, except that
it had been secured from
the nursery of W. A. MANDA
(S. Orange, N. J.), who had
gotten it in a miscellaneous
collection of unknown
sources. This cone, which
atrived in Chicago July 25,
1907, measured 21°" in
length by 10°™ in diameter,
and since the pollen was
nearly mature, this must be
about the size before the
elongation of the axis begins
to separate the sporophylls
and liberate the pollen.
The general appearance of
the cone is shown in fig. 7.
The shape of the micro-
sporophyll and its general
appearance is about as in
D. edule, except that the
microsporangia are much
more numerous, the aver-
age number on a micro-
sporophyll being about 750;
while in D. edule the average
falls a little below 300. The
number in D. Purpusii is
between 300 and 4oo. In
all three species the sporan-
Fic. 7.—Dioon spinulosum; staminate cone
rom a plant in the Missouri Botanical Garden,
x
July 1907.
gia are in sori of 3, 4, 5, and 6 sporangia, with 4 and 5 the most
frequent numbers.
412 BOTANICAL GAZETTE [DECEMBER
While it is hardly safe to arrange the three species in an evolu-
tionary sequence before the life histories have been studied, it seems
to me that D. spinulosum is the oldest and D. edule the most recent,
so that the series should be D. spinulosum, D. Purpusiui, and D. edule.
In favor of this sequence it may be said that D. spinulosum has a
spinulose leaf throughout its life history, while D. edule shows the
spinulose character only in the seedling, the later leaves gradually
becoming entire. D. Purpusii has a leaf which is slightly but con-
stantly spinulose in the adult plant. Its seedling is not known.
Regarding the spinulose character of the seedling leaf of D. edule
as due to recapitulation, D. edule is a later development than D.
spinulosum and has come either from D. spinuloswm or from some
unknown form with spinulose leaves. The leaves of D. edule and
D. Purpusii present about such characters as we should expect in
D. spinulosum, if this species should be brought from its well
shaded habitat into the dry hot places where the other two species
are found.
I believe that throughout the Cycadales there has been a gradual
reduction in the number of sporangia on a sporophyll. On this basis
the sequence would be as I have given it.
On the other hand, it must be admitted that in D. edule the ovulate
cone is not so compact and the megasporophylls have not lost so
completely the character of the vegetative leaf, which must be assumed
as the ancestral form of both kinds of sporophylls.
Since the original description of D. spinulosum was necessarily
inadequate and incomplete, it seems worth while to describe the species
from the more abundant material now available.
DI0oN sPINULOsUM Dyer.—Adult plants 2-16™ in height; stem slender, with
conspicuous transverse ribs, and a single zone of wood; leaves 1.5-2™ long,
curved, with 80-117 leaflets on each side; leaflets 15-20°™ long, ro-15™™ wide,
with 5~8 spines on each margin, the lower ones gradually reduced to mere spines;
first leaf of seedling with as few as a dozen leaflets on each side, the leaflets with
only 2-6 spines on each margin, lower leaflets not at all reduced; ovulate
strobilus cylindrical ovoid, 35-50°™ in length, 20-27°™ in diameter; sporophylls
densely hairy, closely imbricate, the exposed portion rounded or obtuse at apex; —
seeds smooth, white, 4-5.5°™ in length, 2.5-3.5°™ in diameter; staminate
strobilus elongated ovoid, 21°™ in length, ro°™ in diameter; exposed portion of
sporophyll hairy, obtuse; microsporangia about 750 on a sporophyll.
1909] CHAMBERLAIN—DIOON SPINULOSUM 413
Observed growing wild at Tierra Blanca (State of Vera Cruz) and at Tuxtepec
(State of Oaxaca), Mexico.
Material has been collected at intervals and a future account will
deal with critical stages in the life history.
THE UNIVERSITY OF CHICAGO
THE INFLUENCE OF GRAVITY ON THE DIRECTION
OF GROWTH OF AMANITA
STELLA G. STREETER
(WITH THIRTEEN FIGURES)
The following account is a record of a series of experiments carried
on at the Biological Laboratory of the Brooklyn Institute at Cold
Spring Harbor, under the direction of Professor D. S. JOHNSON,
during the summers of 1906 and 1908. The object was to determine,
if possible, the reactions of some of the common toadstools to the
gravity stimulus. The main points under consideration are the
promptness and accuracy of the response, the duration of the response
after an efficient stimulus, the location of the zone of elongation, and
its relation to the responsive zone. The conclusions here stated
were drawn from observations made on about 3000 specimens,
collected in the woods and replanted where conditions could be con-
trolled. With the greatest care not more than one out of every ten
planted yielded a satisfactory record. The agarics break easily,
often from their own weight, when placed in a horizontal position;
some shriveled instead of developing, and many were infested with the
larvae of various insects, which fact was not apparent until the toad-
stool was near maturity.
The species used in these experiments were Amanita phalloides
Fr. and A. crenulata Peck. These forms were chosen because they
have long stipes, because transplanting seemed in no way to retard
the normal development, and because they were very abundant.
The food supply is stored in the button, so that the plant is not
seriously affected by removal from the mycelium. The plants were
collected from the woods just after they broke through the ground, at
the stage when the pileus is beginning to break through the volva.
Each was taken up carefully with some of its surrounding soil,
carried to the laboratory, and there planted again in a tumbler.
When it had been allowed to rest in the normal vertical position in a
dark chamber for a short time, a careful drawing of each specimen
was made in the following manner. The plant was placed, with the
Botanical Gazette, vol. 48] . [414
1909] STREETER—DIRECTION OF GROWTH OF AMANITA 415
stipe horizontal, at an accurately measured distance, before a sheet
of paper firmly supported on a vertical drawing-board. In front
of the toadstool and always at the same distance from it as the paper
was fixed a black screen having a pinhole aperture. The drawing
was made by looking through the opening and tracing the outline
of the plant as it appeared against the paper. Other records were
made in this way from time to time, depending upon the object of the
experiment. The plant was in no way disturbed, and these records
showed all changes of position in the vertical plane, and from them it
mas possible to measure these changes in units of angular measure-
ments. :
fo Fic..2
Fic. 1
M Fic. 1.4. crenulata, 11° from perpendicular.—Fic. 2. A. crenulata, 8°5 from
perpendicular. __
A few simple experiments showed that the forms used were
positively heliotropic. Specimens planted in tumblers were placed
in boxes which were painted black on the inside.” One entire side of
each box was left open and the boxes were placed in a west window
‘with the exposed side toward the light. After standing in this
position for 24 hours, the plants had bent 8° to 12° toward the light
(figs. 1,2). In fig. 1 the main axis of the toadstool is shown inclined
11° from perpendicular, and in fig. 2, 8°5. To avoid light stimulus,
all experiments with reference to geotropism were performed within
a moist dark chamber, which in turn was kept in a dark room.
_ After the pileus broke through the volva, it took the stipe about
24 hours to attain its full length in A. crenulata, and nearly 36 hours
‘in A. phalloides. With a few exceptions this time element was con-
416 BOTANICAL GAZETTE [DECEMBER
stant. This short period of development necessitated that all
observations on one plant should be made within 36 hours.
In those experiments which required that the plant be held in a
horizontal position, the tumbler containing the toadstool was sup-
ported firmly on a wooden block by a band of tin nailed securely to
each side of the block (figs. 3, 4). A slender insect pin was placed in
Fic. 3.—A. phalloides, in which supra-curvature has been neutralized.
the center of each toadstool as a continuation of the axis of the stipe
(also shown in the figures). This pointer made it possible to measure
the amount of curvature accurately. After being collected and
planted, each specimen was left in the normal position long enough
to counteract any stimulation received during its transference and
then it was placed on its side in the dark chamber.
Usually the pileus does not become fully extended until after the
1909] STREETER--DIRECTION OF GROWTH OF AMANITA 417
stipe has ceased to elongate (fig. 5). In 24 hours after the toadstool
had reached its maximum height, the pileus expanded and its diameter
increased 1.2°™. In all cases where the plant was placed on its
side after the stipe had reached its full length, but before the pileus
Fic. 4.—A. phalloides, from which the pileus, except that part directly above the
Stipe, has been removed.
had fully opened, the pileus continued to expand; there was, however,
no upward bend in the stipe (also shown in fig. 5). After the stipe
attains its full length there is no longer any response to gravity
stimulus.
When a young plant, in which the entire stipe is still elongating,
is placed on its side in the dark, the tip of the stipe begins to bend
418 BOTANICAL GAZETTE - [DECEMBER
upward after 40-60 minutes. This curvature is continued for about
24 or 36 hours, aie aoe: upon the species, until the tip = the eas
- 65cm
Fic. 5.—A. crenulata; a, height 6.5¢™, diameter of pileus 5.8°™; 6, 24 hours
later, height 6.5°™, diameter of pileus 7¢m,
Fic. 6.—A. crenulata: a, as planted; b, 24 hours later, showing supra-curvature
of 31°.
is carried up to and beyond the vertical position, and the original
lower edge of the pileus is carried above the horizontal plane (jig. ©).
1909] STREETER—DIRECTION OF GROWTH OF AMANITA 419
In experimenting with the stem of Cephalaria procera, one of the
teasels, Sacus (1888) found that this supra-curvature was neutralized
BA ish Sirty AT ty eal EE
|
_ __ Fic. 7.—A. phalloides: a, as planted; 6, 6 hours later, poms tie eet
: of 20°; c, 17 hours after planting, having returned to 10° below vertical; d, 30 hou
_ after planting, tip of stipe vertical.
and the stem soon moved back to the vertical position. In the case
420 BOTANICAL GAZETTE [DECEMBER
When young specimens of A. phalloides, which have longer stipes
and respond more quickly, were used, the tip of the stipe was carried
beyond the vertical 2° to 20°, then it stopped and moved back toward
and beyond the vertical 1° to 6° on the other side, and by a repetition
of this process finally came to rest in the vertical position. ig. 7
shows a series of drawings of one specimen of A. phalloides in which
the supra-curvature was neutralized. Fig. 3 shows this toadstool
just before it came to its final vertical position. This fluctuation
only takes place if the plant is still growing when the induced response
ceases.
In an attempt to locate exactly the perceptive zone, all the pileus
except that part directly above and which forms a continuation of the
stipe was removed in the manner shown in fig. 8. These plants were
then allowed to develop in the dark in a horizontal position for 24
hours, and the result is shown in fig. 8. The stipe itself bent, but
there was no curvature in that part which belonged to the pileus.
This shows that the responsive zone is not situated within the pileus.
The entire pileus was then carefully removed from the tip of the
stipe in many plants by a transverse cut where the gills join the stipe.
Each specimen was then placed in a horizontal position in the dark
and allowed to remain 24 hours. The geotropic response here was
normal (fig. 9). The stipe, which was bent downward at first, began
to bend upward slowly, then more rapidly, carrying the tip beyond
the vertical. This shows that the responsive zone is situated within
the stipe.
A further attempt to locate the responsive zone was made. Glass
tubes were cut in pieces of different lengths and these were placed
over the bases of the stipes of plants from which the pileus had been
removed. This left 1-4™™ of the upper end of the stipe exposed
beyond the end of the tube. These tubes were held firmly in a
horizontal position by wire, and the plants were kept in the dark for
24 hours. In every case where elongation had not ceased, there
was a decided upward curvature of the stipe beginning at the end of
the glass tube (fig. 10). In this case the stipe was 8™™ long, 2"™ of
this projecting beyond the end of the tube when the experiment was
set up. After twenty-four hours the stipe projected 217” beyond
the tube. It had curved upward at the end of the tube, making an
1909] STREETER—-DIRECTION OF GROWTH OF AMANITA 421
angle of 145° with the position from which it started. This shows
that at least part of the responsive zone is very near the tip of the
stipe. In other cases, where the stipe had nearly reached its greatest
elongation, the result was the same (fig. rz). Here the stipe was
Fic. 9
Fic. 8
Fic. 8. A. crenulata: a, entire; b, as planted, the pileus having been removed as
indicated by the lines, dotted lines show depth of pileus; ¢, 24 hours later, showing
that curvature takes place in stipe, not in pileus.—Fic. 9. A. crenulata: a, entire; b, as
Planted, the pileus having been removed by transverse cut ab; ¢, 24 hours later, show-
ing curvature of 124°.
56™™ in length, of which r™™ projected beyond the end of the tube.
+ . . . . mm
In this case elongation continued until the stipe projected 3™™, and
it then showed an upward curvature of 2 3°. In this case the respon-
sive zone must have been within 1™™ of the tip at the start.
In order to determine the distribution of the zone of elongation,
422 : BOTANICAL GAZETTE [DECEMBER
the stipes of a great many specimens in all stages of development
were measured. An accurate record of the length of the stipe at the
beginning and end of growth was kept. The stipe was marked off
into 2™™ lengths with dots of waterproof India ink. It was possible,
Fic. 10 Fi, 11
Fic. 10. A. crenulata, 24 hours after planting; base of stipe held in glass tube;
tip curved 145°.—Fic. 11. A. sane, 24 hours after planting; base of stipe held in
glass tube; tip curved 23°.
when growth ceased, to tell in what region elongation had taken
place and where it was most rapid. A few of these records are given
below.
n
.] eo i O a
4/8 /ele |g Bg ‘ g Bees Ca
ic rh, 2 a = oo - S . aw | 3
3/38 3/6 | or a 3 Fs 2, tS | Ss
» & 15 S28 o ay n gaa en
& /A | 8 be ee 3 E Se | 2%
“3 a] 2 g =] sR cs i>! & “Bo &
a 7 o 3 ald E = a 9d ve
i 4 silo 18 aoe “ o es ei eg
, |Ss1° | 218 jee Seq 2 2 = gz | 33
5 2 |S 64 Be > > = =I be]
5 |S Bla Sis |ss 20.5 =) a so ao
eM et) 2h vo bo Sp ~ am a am ag cr)
| esiagi g BO) gw gao a rol + es ES &
5 |/o-|o% &§ aos eee of] 6 =
Zin |i a 12 25) 4 4 A Oo 3)
mm./mm./mm.|mm.|mm 3 m mm. mm. % % | hours
110 7 | 33 | 26 © | 7-10-53-34-0 2 100 36
216 | 20 | 50 | 30 | 20] 0 | 3-3-3-3-5 4-3-2-2-2 4 100 36
218 | 30 | 68 | 38 | 30 | 0 | 2-2-3-3-4 4-4-3-3-2 ese 1-1 44.1 | 100 36
157 | 40 | 72 | 32 | 40 | © | 3-4-3-3-2 2-2-I-I-1| I-1~1-1-1| I~1-1-1-1] 55.5 | 100 36
104 | 20 | 34 | 14 | 20 | © | 1-2-2-2-2 I-I-I-I-1 58.8 | 100 36
142 | 30 | 42 | 12 | 20 | ro | 2-2-2-1}-14 | 1 971.4 | 66.6] 36
148 | 42 | 52 | 10 | 20 | 2 I-2-I-I-1 i-1-1-44 80.7 | 47.6} 36
138 |102-|104 | 2| 81 9 4 98 7.8] 36
123 | 36 | 364 4] 2 | 34 | 4-c-c-o-0 : 08.6 5.5] 36
The specimens described above were grown in a horizontal posi-
tion, and the measurements were taken on the lower side. Comparing
the length of the stipe at the beginning and at the end of the experi-
ment, and then comparing the length of the zone of elongation with
the length of the entire stipe when the first measurement was taken,
we find that elongation takes place throughout the entire length of
the stipe until after it is 60 per cent. grown. From this time until
ee
Ree TPE ed ee wee coe
ey She aed
Ss a Bid oh
as
4
"
<
q
z
3
a
4
q
y
1909] STREETER—DIRECTION OF GROWTH OF AMANITA 423
growth ceases, the zone of elongation becomes shorter and shorter,
but is always just below the pileus. In the specimens used to make
out the above table, the length of the mature stipe varied from 36
to 112™™, and the length of the zone of elongation varied from 2
70.407,
Record was made of the amount of elongation which had taken
place in each part of the stipe beginning at the pileus. By referring
to the table it can be seen that in those plants which are about one-
third grown or less, the zone of most rapid elongation is in about the
middle of the stipe. As growth continues, this zone moves up the
stipe. In plants which are half grown or larger, the zone of most
vigorous growth is the second 2™™ from the tip. When the zone of
elongation becomes less than 4™ in length, growth takes place in the
upper 2™™ (see record for 123). The elongation within the upper
2™™ of the stipe is usually less than that within the second 2™™, but
in some cases they are equal. The amount of elongation in each
2™™ becomes less and less from the point of most rapid growth
toward the base, until the growing region is passed. :
In order to determine the time element in the geotropic response
of these toadstools, plants were placed in a horizontal position in the .
dark and records of the amount of curvature were taken each hour.
The following table gives the records of two of these specimens:
No. 51 No. 56
Time igo Pe of Amount of
an change ses change
Position foreach Position tc back
successive hour successive hour
nh: Se SRA eae eer. °° or
BAO A Me. cc ain s —4° —4° "a 5°
RESO A. Meee cee ee ee =" Ss? og ic”
BAS Ming coe ec ewe te ts 5 4° ar ee
MAGA Moo vise cee he ee 8° 4° 32° 9°
Wao Mok se tee ee tr” = 42° 10°
EW sk ld woes ee re 4° 52 10°
00 SG ESSE aia ar rrae ar rar| 19° 4° 62° 10°
ee Pe ee ee ce 22° is 2° 10°
3 3
ee POM ees es eS 24 2° 82° 10°
Be eM ha hee oss Ace 20° 2° 88° 6°
See PMA op eee 28° 2° 92° 4°
es Mile = vain gees 30° 2° 95° ss
a errr | 32° 2 97° 2
ee Ms ea is as 32° 0° + 98? ig
Be A, Wee i Sa eee ws 32° 0° 98° 0°
424 BOTANICAL GAZETTE [DECEMBER
In about two-thirds of all the plants placed in a horizontal posi-
tion in these experiments, there was a bending downward of 1° to 6°
during the first hour, before there was any observable upward curva-
ture. This may be partly due to wilting caused by transplanting.
In general this downward tendency was less in the younger specimens
where the stipe is shorter, and it was less where the pileus had been
removed. ‘These facts seem to indicate that it might be the physical
effect of a new lateral strain rather than a response to a new stimulus.
For this reason in many cases the pileus was removed, as is shown in
jig. 4. No. 51 shows this bend downward in the first hour, followed
by 1° more than complete recovery in the second hour. For the next
six hours the rate of curvature fluctuated from 3° to 4° per hour;
this was followed by a steady rate of 2° per hour for five hours; then
the pileus came to rest at an angle of 32° from horizontal. In No. 56
the response during the first hour was slight; during the second it
was greatly accelerated; this was followed by a period of depression
which lasted for one or two hours; from this time on for the next five
or six hours the reaction was constant and rapid, then more slow.
After the vertical line was passed, the curvature took place more
-and more slowly until, in the case cited here, it came to rest at an
angle of 98° from its original position. Nine hours later, or 24 hours
from the start, it remained in the same position and there had been
no increase in length. There was no neutralization of the 8° of supra-
curvature.
In order to determine the exposure period, that is, the length of
time which the plant must be stimulated in order that reaction may
follow, several plants were kept in a fixed horizontal position for 15
minutes and were then rotated on a clinostat about the horizontal
axis for 24 hours. The plants gave a decided reaction to geotropic
stimulation for this length of time. There was an upward curvature
of the stipe varying from 1 5° to 30° from its position during exposure
to the stimulus. Four records of plants of A. phalloides, stimulated
by being in a horizontal position for 5 minutes and rotated on Md
clinostat for 24 hours, showed an upward curvature of 7°, 10°, et
and 15°, respectively. Eight records of plants of both A. phalloides
and A. crenulata stimulated for one minute all show an upward
curvature of either 6° or 7°. In one case of stimulation for 5 minutes,
aa ee a EE
1909] STREETER—-DIRECTION OF GROWTH OF AMANITA 425
in three cases of stimulation for one minute, and in all cases (ten
records) where the specimens were in a horizontal position only 30
or I5 seconds, there was no direct upward curvature. Instead, the
stipe had made a definite spiral curvature in the same direction as that
in which the clinostat moved. Clinostats which rotated in opposite
directions were used and the spiral always followed the direction of
the clinostat (fig. 12).
O find the latent period, the pileus was carefully removed that
Curvature might not be retarded by the weight which would cause a
Strain in an unusual place and the plants were placed in a horizontal
position. Records were made every
10 minutes. In young, vigorously
growing specimens, there was an up-
ward curvature observable in 4o
minutes. In other specimens which
were nearer maturity, the period was
longer, in some cases being 60 minutes.
Fic. 12 Fic. 13
Fic. 12. A. phalloides: a, as placed on clinostat; 6, 24 hours later, showing
Special curvature of stipe.—Fic. 13. A. phalloides, showing amount of curvature for
€ach ro minutes for 80 minutes.
No records which showed the downward bend were considered in this
experiment. The diagram (jig. 73) shows the rate of curvature in a
typical specimen.
SUMMARY
When young and vigorously growing toadstools were placed with
the stipe in the horizontal position, the stipe of each toadstool bent
and carried the pileus up to or beyond the horizontal position. This
Supra-curvature when it occurred was neutralized if growth did not
€€ase too soon.
The responsive zone is situated near the tip of the stipe, not within
the pileus.
The stipe elongates throughout its entire length, until it is more
426 BOTANICAL GAZETTE [DECEMBER
than half grown. The zone of most rapid elongation is always just
below the pileus and becomes shorter and shorter until growth ceases.
When placed in the horizontal position, the tip of the stipe curved
upward very slowly at first, then more rapidly, until it passed the
vertical position, after which the curvature took place more slowly
until it came to rest. If growth were still vigorous, the tip of the
stipe again passed the vertical, rested on the other side, and finally
assumed the ordinary position.
The amount of time which a toadstool must be stimulated in order
that reaction may follow is less than a minute. How much less was
not satisfactorily determined, probably because the clinostats used
rotated too slowly. :
The latent period varied from 40 to 60 minutes, the younger specl-
mens responding more quickly.
Jersry City, N. J.
THE WILLIAMSONIAS OF THE MIXTECA ALTA
G. R. WIELAND
(WITH TEN FIGURES)
The great plateau and mountain region in the central and western
portion of the southern Mexican state of Oaxaca is commonly known
in Mexico as the Mixteca alta, or high country of the Mixteca Indians.
This name is used in contradistinction to the Mixteca baja, or portions
of the lower country or tierra caliente over which the Mixtecas have
extended. Simply speaking, then, the Mixteca alta is a portion of
the southern edge of the Cordilleran system facing the Pacific and
extending through western Oaxaca to the border of Guerrero, or into
the latter state. Here, during some five months of the past winter
and spring I have had the pleasure of continuing field work on the
American fossil cycads under the auspices of the Instituto Geologico
Nacional de Mexico. I have the kind permission of the director,
Sefior AGUILERA, to note in this preliminary manner that the results
obtained are regarded as of the greatest interest to paleobotanists.
The field work has included the making of an accurate section
through fully 2000 feet of plant beds of Rhit-Liassic age, full of
cycads in as great a variety of types as has thus far been encountered
anywhere in the world. Indeed, considering the fine material ob-
tained from the localities noted in the valley of the Rio Nochixtlan
hear Tlaxiaco, at Mixtepec on the Rio Tlaxiaco, notably all around
the Mina Consuelo, about El Cerro del Lucero, and the Rosario region
to the southwest of Tezoatlan, as well as elsewhere, and considering,
Moreover, the almost endless opportunity for opening up quarries in
all this extensive country, I am of the opinion that the Mixteca alta
IS one of the most promising and accessible regions for the student of
fossil plants yet discovered.
True enough, these localities are distant from the railway 50 to
150 miles or more, over the roughest of mountain trails. And as
Mountain succeeds mountain with scarce a valley between, there are
Some real difficulties for the collector, who must send out his material
in blocks of limited size, such as can be loaded on the backs of the
427] [Botanical Gazette, vol’ 48
*
428 BOTANICAL GAZETTE [DECEMBER
tough little burros, or on the strongest mules, which can carry a pair
of boxes of 200 pounds weight each. Hence, it more than once becomes
necessary to break the splendid slabs all covered with leaf impressions,
and often bearing flowers, which one can secure in even the smaller
quarries almost without limit.
But for a country so distant, there are many very distinct advan-
tages and no final obstacles. Animals are trusty; the Indians are
good and cheap workmen; one is everywhere met with great courtesy;
it is a source of much interest to find the high degree of comfort to
be had in some of the most distant of the towns and villages; the
food is always good, and even in the far mountains one can always
get eggs and tortillas. All in all, if one is only fairly fore-wise, to
spend a winter in the sunshine, the forests, and amidst the grand
scenery of the Mixteca alta is much more like enjoying oneself in
some geological Sanatorium, as it were, than like-hard work. For
the naturalist ever finds a thousand and one points of interest, and
soon becomes accustomed to ride 20 to 50 miles a day as he may
need; while if interested in the cycads he can find places farther
_down the cafions and deep valleys where species of Dioon are fruiting
hard by strata yielding the fossil forms in profusion.
The great thickness of these Oaxacan plant beds has been noted;
but as to their exact age I am not sure, it being as yet early to form
a fair conclusion. Glossopteris, rather than merely the sage
Pterids, is considered present; and there is also a wealth of taenio-
pterids of older type, as well as a fine series of stems of a small but
distinct lepidodendrid, and many leaves of Noeggerathiopsis Hislop
Bunbury. But otherwise the facies is uppermost Triassic, if indeed
Liassic genera may not in the end be found to preponderate. A
similarity to the Gondwanas of India suggests itself.
But what commands our attention at present, far beyond the
precise age of these beds, is the fact that there abound in them In
great variety the imprints, casts, and molds of many fruits of Wil
liamsonia, closely associated with Zamites, Otozamites, Podozamites,
Pterozamites, P tilophyllum, and Dictyozamites, fronds as well ae
seeds. One of the strobili is a mold of just such an ovulate fruit as
BUCKLAND figured under the name of Podocarya in the Bridgewater
treatises, the original of which should be at Oxford, but could not be
1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 429
found when a search was made for it a few years since, as Professor
SEWARD of Cambridge has informed me. Also, there is a con-
siderable number of the large buds inclosed by heavy ramentum-
covered bracts of the same size and appearance as those from the
Yorkshire coast. One favorable circumstance that has conduced to
frequent preservation of the surface characters of the ovulate fruits
is the formation by the outer zone of a layer of coal, which while
liable to checking affords an excellent indicator for which one may
keep constant watch. Furthermore, the close association of these
fruits, leaves, and stems, though the latter are not well preserved as
a rule, leads to the hope that as the collections come to embrace a
wider range of localities, and the data of association come to be
better known, more than one restoration of the complete plant can
be made. That silicified forms may yet be found is proven by the
occurrence of a well-silicified log of a new species of Araucarioxylon.
Especially interesting is the occurrence at Mixtepec on the Rio
Tlaxiaco of fruits of small size borne on slender stems, and also those
with broad bladelike bracts of thin texture, if they are not indeed
Sepals or petals. These small fruits, while not preserved in finer
details, are abundant, and are quite uniformly accompanied by
Small, much-branched stems, and by numerous fronds no more than
Io°™ in length; though these may have been bipinnate.
Of primary importance is a single fairly well-preserved impression
Of a staminate disk from midway up in the plant beds in the main
barranca between El Cerro del Venado on the south and El Cerro
del Lucero on the north, near the coal outcrops of Mina Consuelo,
15 miles from Tezoatlan. On my return from the Mixteca alta I
supposed that I had not found any of the staminate organs of the
cycadophytes; although various interesting fruits of seed ferns
appeared to be present. But I found on my desk at the Instituto
Geologico a letter from Professor NATHoRsT, dated from England
and telling me that he had just visited the Yorkshire coast, where
he had succeeded in finding the first definitely recognizable male
flowers of Williamsonia, these agreeing essentially with the flower of
Cycadeoidea as first discovered in the type of C. ingens and described
in my Studies of American fossil cycads, parts I-IV.
It can be readily understood that I had kept a sharp watch for
430 BOTANICAL GAZETTE [DECEMBER
such disks during all the field work, and that after reading Professor
NatuHorst’s letter this watch was made closer still while the various
specimens were being unpacked, placed in order, and further
developed. But not until all this work had been done did I finally,
in an idle moment, uncover a staminate disk on a slab from near
Mina Consuelo. Then I recognized that a form I had suspected at
one time was a disk had been truly such, though poorly preserved.
It seems I had not chanced on quite the best disk locality. Better
localities will yet be found. .
The El Consuelo Williamsonia staminate disk is a reduced cam-
panulate form of the size and general structure indicated in jig. 2.
As there shown, however, the number of fronds is arbitrarily taken
for purposes of interpretation as five, instead of the true number of
eight or ten. One cannot be quite sure of the exact number in the
specimen. The important structural feature, however, is that instead
of a bipinnate frond as in Cycadeoidea,' there is a small strictly
once-pinnate form,. the rachises bearing only two lateral rows of
synangia. These, however, are still of the marattiaceous or cycade-
oidean size and structure. The component fronds project beyond
the disk only to a height of about r.5°™, The basal region appears
to be rather thin in texture ; but the state of preservation as well as
the association with other fruits and leaves all go to indicate that
these disks and doubtless those of other species and genera should
yet be found in abundance. :
There can be no gainsaying the supreme importance of this fossil
flower in enabling us to form more exact and adequate conceptions
of the course of evolution leading up to and resulting in the present
diversity of gamopetalous plants. In describing the flowers of
Cycadeoidea ingens and C, dacotensis, I pointed out that the disk
type of cycadophytean flower clearly indicated previous stages with
the staminate organs spirally inserted beneath an apical cone wie
series of likewise spirally inserted megasporophylls, and that readily
conceivable reductions and changes in such a primitively via
inflorescence or fertile apex or branch fully indicated the mode st
origin of Liriodendron. Whence it followed that the Magnoliaceae
: ita s Sell
‘I followed the old usage of calling these fronds pinnate in my descrip ae a
ARBER has called them bipinnate forms. It seems rather more correct so to a0.
I if AT
gog] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 431
os if not the most primitive of all the angiosperms. In
pendentl vetoes ese: the first; though HALLIER soon inde-
y reached similar conclusions as to the origin of the Magno-
a and likewise cited Liriodendron.
eco. and PARKIN visualized in the Annals oj botany the
crown of i Gree co cadean angiosperm ancestor with its
surmounted a ieee dase 5 irally inserted microsporophylls
a. y similarly set carpophylls; and these authors at the
etn tae much further the idea that the true mode of angio-
all its broad eeaser long completely hidden, was at last indicated in
3 aes outlines by — direct evidence.
a Racha and PARKIN Ss ancestral stage we certainly behold a
a. and decidedly plastic type, which they choose to call
under SE though I perversely prefer to group such plants
hypothetic ae S old term of proangiosperm.’ It is one of the
= orms, moreover, which is not only so readily conceivable
. infinity of modifications in the direction of higher
Blentiy : one which, as I have long since told ARBER, we may con-
Sl will yet be found in the fossil stage.
into th . ae this progress, the actual mode of modification leading
re complex types of angiospermous flowers has remained
grow “ : .
Sa hemiangiosperms,” as he has proposed. I duly
s of importance that they receive a more thorough consideration than can
be accorded
them here.
should duly honor SAPORTA as
psed an important truth when
To claim that the proangio-
. ae the angiosperms, could have their gymnos
iid He ude other truly lineal families,
Diane m the Cycadeoideae at best. For these reasons,
at ae that to use fairly the term hemiangiosperm we farth
’ ere by another hiatus the proangiosperms merge into the more primitive
fern derivatives.
432 BOTANICAL GAZETTE [DECEMBER
obscure. While Scort, especially, as well as HALLrER, ARBER and
PARKIN, BEssEy, and others, as well as myself, have all insistently
urged that the path has thus really been blazed to a knowledge of
the evolution of the angiosperm groups, no one has yet been ina
position to bring the final methods more clearly into view. Now,
however, I believe we can do so in the case of all but the extremely
modified families, if not indeed ultimately in these too, by means of
analogic methods combined with comparative morphology.
We have seen how the staminate disk of Cycadeoidea ingens, and
of all the other species so far known, bears inside the campanula or
androecium many functional synangia on the raclhial axes, either
inserted directly or on pinnules. Now we see, furthermore, that the
campanula remains large in a form with greatly reduced fronds,
while we may be sure that interiorly borne synangia are still present
on the rachial axes, or at least may be in related forms, whether we
can detect them or not. Whence it follows that a slight further
continuance of the rachial reduction, so plainly under way, must
result in a toothed campanula bearing interiorly on each axial or
rachial line only a single pair of synangia and finally a single synan-
gium and no more, just as diagrammatically shown in jig. 3. uch
types we may call, because of the strictly convolvulaceous aspect,
archaeosolandrous, arbitrarily dismissing for the present all mention
of the central ovulate region to which we return below.
Now plainly, having thus by a series of entirely simple stages
reached this archaeosolandrous form, which we confidently believe
will be detected in the fossil condition, it is only a minor step t0
simpler types of pollen sacs, either borne in pairs or singly, and
finally to elongations of the filaments suiting the requirements of
such flowers as that of jig. 4, which is none other than a common
morning glory,
In short, the successive members of the series of steps outlined
are these, letting capitals represent the known, and small letters the
hypothetical plants:
A’, Proangiosperms, or hemiangiosperms and pteridosperms. Pee
A. The flower of Cycadeoidea dacotensis, with a campanulate disk of 18 bipin
nate members
B. The flower of C. ingens, with 12 bipinnate members.
1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 433
C. The flower of C. Jenneyana, with only 1o bipinnate members, as well as -
various other greatly reduced and small types of flowers of Cycadeoidea.
A hypothetical flower of Cycadeoidea, with a staminate disk of 5 bipinnate
members or staminate fronds (cf. jig. 1).
Fics. 1-4
2 The El Consuelo staminate disk composed of 10 or 12 pinnate fronds.
vy
A derivative of the El Consuelo disk, with only five pinnate fronds forming
the Campanula (cf. fig. 2).
A hypothetical campanula derived from the preceding by reduction of the
Synangial number to two and finally one, borne interiorly (fig. 3).
434 BOTANICAL GAZETTE [DECEMBER
od
Unknown intervening plants derived from g and undergoing reduction in
the number of the sporangial loculi, with thinning of the synangial wall, or
An unknown form much like g, but with a simpler type of pollinial organi-
zation. (This is the more probable member of the direct series, but bot
may be conceived of as having once existed.)
A campanula derived from either # or i; in which reduction to the angio-
spermous pollen sac has taken place, and in which elongation of the stami-
neal pedicels or filaments is going on (cf. fig. 4).
The staminate campanula of the conyolvulaceous and many other gamo-
petalous flowers.
=.
=,
2
Thus may we derive the staminate zone of gamopetalous forms
by a series of readily conceivable and closely united reduction stages,
the principal members of which are in the larger sense already
known. But let us now see if it be possible to go on and establish
a plausible ovulate correlation; for if this cannot be done it is more
than superfluous to say that K is in the extended sense not proven
to be a true member of the evolutionary series A’, A-j. :
That an apical series of spirally inserted carpophylls giving Tse
to a central ovulate cone played the chief role in the development
of the Magnoliaceae, as in all the conifers and doubtless many other
forms, is evident enough. But that such a cone was in all cases
organized, or much less that a terminal group of diffuse carpophylls
was present in all the ancestral phyla of the angiosperms, is after a
little consideration seen to be a cumbrous hypothesis. By what
other means then than by the reduction of the carpophylls and of
cones may we conceive of the cognate origin of the ovulate region in
angiosperms?
Perhaps the Draceneae may be made to give an initial anew:
Take for instance the cultivated maguey (Agave) of Mexico, with its
six immense versatile anthers borne on their long projecting filaments
as seated in the interior surfaces of the six fused sporophylls, three
of which are smaller, and the other three of which are alternately of
larger size. On cutting this flower open and viewing it from the
interior, is not the structure in reality that very diagrammatically
indicated in fig. 5?
Now, was not this floral structure derived from a cone
and changing whorl of six primitive bisporangiate fronds with bass
megaspores and apical microspores? The simple method of deriva-
1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 435
tion from such a primitive, or archaeo-amarillidaceous plant would
consist in basi-lateral fusion of the sporophylls and development
of a trilocular ovary, with the synchronous reduction and change of
the microspore zone to the series of six interiorly borne stamens, after
the manner shown to be feasible in the above series A’, Aj. Such
Wwe conceive to have been the origin of the yuccas and agaves; for
it is no more improbable that heterospory should in many primitive
stocks arise thus regularly in each of an apical whorl of sporophylls,
than that it should find expression in the
Segregation of a basal group of megasporo-
phylls followed by an apical group of micro-
Sporophylls, as in Cycadeoidea.
Evidently in Agave americana the last
Stage of fusion resulted in the suppression
of the basal or megaspore region of three
alternate fronds. Nor is it so difficult to
conceive how, the plant finding the inclosure
of the ovarian region to its advantage, an
elongation of the style finally resulted, with
the retention of the gametophytes and seeds.
Also, the long filaments must have been .
very readily produced by the flower under
the stress of impulses that had to do with }
nothing else than the ordinary phenomena of fertilization. Such,
Surely, are the conclusions one may reach from the macroscopic
Xamination of flowers like Agave and perchance likewise of the
Tose hip.
While the manner of evolution just outlined is in reality not
utterly different from that of the Magnoliaceae, the order in which
the parts are segregated clearly indicates a remote separation of the
several stocks involved, and therefore the virtual polyphyletic origin
of the angiosperms. But of course, when the initial changes, and
When the major or crucial changes leading up to the two groups now
Considered so briefly, took place, and which group is in reality the
More ancient, are questions that only the future may answer.
Having seen that the ovulate region, whether locular or strobilar,
and whether there are few or many ovules, offers no impassable
436 BOTANICAL GAZETTE [DECEMBER
hiatus, it becomes desirable to interpret a few more examples of
staminate organization leading toward or into the more complex
types of flowers. Thus may we best test our theory and see if it
applies to petals and stamens generally, and really affords a far-
reaching explanation of floral constitution in the angiosperms, with
ultimately a better basis of classification. But in so doing we may
only take up a few forms; for an exhaustive analysis of the families
based on the necessary histological and developmental data must be
a truly gigantic task for many years and many workers.
Various gamopetalous flowers have the structure shown in fig. 6.
Apparently the stamens alternate with the lobes of the corolla in
b
Fics. 6-8
such forms; but on closer examination it is seen that in reality the
axis of the component leaves has shortened to form the notches.
This difference, so convenient in classification, therefore rests on
very slight anatomical distinction, unless it can be found to accom:
pany a particular juxtaposition of the ovules throughout the groups
question. My example is from a shrub I found growing on the
slopes of Popocatepetl, though anyone may turn to Gerardia and
Pentstemon as equally good examples of this type of androecium.
Again, the cruciform flower invites attention, whether it be regarded
as an approach toward or a departure from distinctly gamopetalous
types. For in the cruciferous flower, although the stamen is appat
ently inserted on the common receptacle, rather than as in the dia-
gtammatic fig. 7, there is considerable doubt if it is to be regarded
as of discrete origin. Instead, it would seem more probable that
1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 437
although the point of stamineal attachment has become strongly
depressed and indeed is virtually basal now, the flower has arisen
very similarly to that shown in fig. 4. The two single stamens
alternating with the two pairs thus form an opposing analogy to the
Suppression of megaspore regions in the Agave. But.other explana-
tions are also possible. For we believe that in the angiosperms
petals have developed from bracts, that they have resulted from the
complete sterilization of sporophylls, and that, as explained above,
they result in vast numbers of instances from the apical expansion
of a sporophyll, which, though greatly reduced, may still bear either
Megaspores or microspores or both.s And furthermore, we regard
the stamens of Liriodendron as final reduction stages of individual
sporophylls that were once large.
Of further interest in the cruciferous flower is the fact that little
or no difference in the development of the petals accompanies the
Staminate change. But, on the contrary, in the diagram of a honey-
suckle (jig. 8), while the stamens are of normal number and size,
3 There also appear to be various instances of more or less completely salver-
shaped corollas, in which what are usually called the sepals are in reality fertile or;
alternate with the petals, between which they press and fuse up to the beginning of
the lobes of the corolla, and there bear stamens just as do the petals. Take for instance
those forms with four “sepals,” four petals, and eight stamens borne four on the
petals and four alternately between them, but plainly scaling off with the members
of the calyx. The cherry (fig. 9 from GRayY)
xa t one
retaining more stamens, these not being so
distinctly determinate in number. (They may
be of the inner row.)
Perhaps as great a difficulty as we meet
with discrete hypogynous stamens and a free
multiovulate ovary with an apparently distinct
axial relation, for here there are several pos-
sibilities. Naturally that first coming to mind is that of a central carpellary whorl,
followed below by a staminate whorl, and then by the members of the floral envelope.
But another method needs to be reckoned with, namely, that which may be seszind
characterized as a completed supero-axial shortening and consolidation of the bi-
Sporangiate fronds of an apical whorl, in such manner J
Pinnules assumed a vertical position and fused to form the ovary, style, and stigma,
While the more apical microspore regions of these same fronds produced the stamens,
the frond tips finally forming the corolla.
438 BOTANICAL GAZETTE - [DECEMBER
the members of the corolla undergo division into a major and minor
group. And plainly, from these simple phases we may no doubt
ultimately pass by as simple steps and combinations to a reasonable
interpretation of all the multifarious reductions, ‘suppressions, and
alterations in first one set of organs, and then another, resulting in
papilionaceous, orchidaceous, and all the manifold forms of angio-
spermous flowers.
It is obviously not feasible adequately to show the derivation and
the complex relations of sporophylls leading from the primitive to
the higher types in any simple manner. Above all is this true because
of the necessity of taking into account the varied possibilities and
phases of monoecism and dioecism in any even approximately com-
plete presentation. And the different rates of reduction at different
periods, we are bound to assume, further complicate the problem.
Indeed no one diagram and no one set. of diagrams would serve to
outline adequately the changes now suggested. Nevertheless, the
attempt is made in jig. 10 to give the simplest and most abbreviated
expression of sporophyll change possible.
Have not the transformations really been easier than we think?
Dictyozamites, the net-veined cycad, and many net-veined ferns of
which some were doubtless seed-bearing, together with the forms of
unknown fruit like Cissites, Vitiphyllum, and Liriodendropsis, all
go to show that there is no special hiatus between the angiospermous
foliage and the more primitive seed-bearing plants. A single new
locality in the upper Triassic or lower Jurassic may at any time com-
pletely close the foliage gap. Again, the stem structure of the ang:
sperms presents no difficulty of derivation from the older types,
which free branching is already known, as well as the presence of
numerous flowers undergoing great reductions and changes.
The great double funnels of the near-by Ipomoea, nearly a foot
in length, show how readily fusions-have gone on, and how great
must have been the changes, reactions, and alterations going on for
ages in all floral organs. The balance once disturbed, or a critical
stage or plastic form once accomplished, infinite changes in a truly
polyphyletic race set in. ar
Other fossil evidence for metamorphosis and reduction will be
forthcoming, and speedily. But the student of fossils now realizes
”
1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 439
ae fg To. BS Boat Siacrine and actual sei a the See of ee
pothetical homosporous fronds.
"8, heterosporous pteridophyte
4,h
dices Romosporous ear 7 pteridophy tes pines:
a ; an prey of B (Permian; Cycas); BY”, staminate derivative of B
etalous angiosperms; D, fu rther
all the essential organs and parts
carpel, stamen, petal, a and sepal
C, reduced form of B
and a "progenitor of famop
reduction stage of C, with, seenaath of giving r
a pet tfect flow ee pee stamino-petal ‘D";
greed derived from BF
a, true ca
pitlalers carpellary leaf; b, reduced carpellary leaf;
I, true a frond (Williropen ESO - sa leading to gamo-
reduc rue stamino-petal; 4,
c, pedicellate ovule or seed
rms;. 2,°tr
Gr 3’, a7 ’, second method a sepa petals iets
Cyca We Shih AD xEs.—B’ + B” (I-IV) =Co ectatta)et; Coniferales, Ginkgoales,
Ma, et A+C Vi Cra raat many proangiosperms; A’'+C (VD=
Cc agg laceae, Liriodendropsis, etc.; C (VIl)=many types of naked cg ictal
spe (VIII) =gamopetalous a gee ae forms; eae =many a
t™ms; A +a=proangiospe
440 BOTANICAL GAZETTE [DECEMBER
that the proangiospermous or hemiangiospermous plant types
which will exhibit critical developmental phases are likely to be
inconspicuous, and that they must be studied with extreme care.
Our hypothetical archaeosolandrous type, for instance, could be
very easily missed, though found in excellent preservation. It will
be necessary for that fortunate collector who finds the horizon and
locality with lineal members of the early angiosperm line imbedded
in it, to apply to his material all the newer laboratory methods,
namely: (1) the staining, imbedding, and sectioning method used
by JEFFREY and Ho ttick in dealing with forms apparently more
like impressions or carbonaceous material than the partly preserved
structures such as they finally found; (2) the developmental method,
by means of which BEECHER showed the preservation of the most
delicate trilobite structures, and won such clear results; (3) the
collodion method of NatHorst for recovering microscopic surface
details, which are often present.
‘That intermediate types will be found in increasing number can-
not be an idle prediction. That from tinie to time there will be found
types definitely hypothesized, may be hopefully expected. Ten
years ago I predicted the discovery of the seed ferns, now known in
such number and variety. Even then it had become clear that
“progressive prothallial elimination with correlated spore differentia-
tion and alteration of the frondlike sporophytes of primitive ferns
of the marattiaceous or an allied group were the basal factors in the
evolution of the cycadofilicinean and cordaitean alliance.” And it
already seemed probable that the angiosperms could be added in
this statement.
At the present time these groups seem to present more and more
distinct points of contact, though in a very complex manner, oer
ently calling into requisition nearly every thinkable modification of
the monosporangiate and bisporangiate frond, both on the same and
on separate axes, and with nearly every conceivable variety of os
arrangement, reduction, sterilization, and suppression. Even m the
Cycadales, the better known of which form a really compact group,
we have been compelled to say that the orders “do not appear “
have passed through precisely the same. evolutionary sae tones .
heterospory, bisporangiate or monosporangiate, monoecious, 42
finally doecious fructification.”
1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 441
And once more, we are compelled to hypothesize an extensive
and far-reaching polyphyly for the angiosperms. But, none the less,
the thought is also present that once an approach has been made
along all the available lines of evidence, this seeming maze of possi-
bilities may in the end be found vastly simpler than one can now
Picture. At least we are already persuaded that the day will come
when the true relationships and derivation of every angiospermous
family will be worked out and satisfactorily stated with mathematical
precision.
EL Instiruto GEoLocico NACIONAL
MEXICO
SAP PRESSURE IN 'THE BIRCH STEM
“PART I
H. E. MERWIN AND HowaARD LYON
(WITH FIVE FIGURES)
During the seasons of 1902 to 1904 sap pressure observations were
made on several kinds of trees in the vicinity of Oneonta, in central
New York. Birches and maples illustrate the two extreme types of
sap pressure phenomena. Our observations on the maples are in
accord with those of other observers, especially as set forth by JONEs,
Epson, and Morse.' Sap pressure in the birches has not been
studied much hitherto, except as incidental to other studies.
We found that glass tubes of small bore filled with mercury made
very sensitive pressure gauges, especially if the tap hole in the tree
and the connecting tubes were filled with water or sap when the gauge
was attached. When pressure was negative (suction), a bulb tube
was sometimes arranged to allow water to flow into the tap hole, and
to catch the gas which escaped. Gas in the tap hole when pressure is
negative causes disturbing capillary effects. Gas in the tubes has a
damping influence upon the gauge.
Characteristics of sap pressure in the birches
No sap will flow from tap holes in the stem of the birch or ooze from
cut twigs till the ground has thawed considerably in the spring.
It is not necessary, however, that the air temperature be continuously
above the freezing point before pressure becomes high. From April 5
to April 22, 1904, we have recorded seven nights in which the tempera-
ture was below freezing; yet on April 5 a positive tension of 44.3°™
was observed in a yellow birch (Betula lutea); April 9, 87°™ in a
black birch (Betula lenta); April 18, 3 5°™ ina black birch. F reezing
nights were often accompanied by negative pressure which was
maintained for a few hours after sunrise. The maximum pressure
comes about a month after the first decided appearance of pressure.
The buds by this later time have begun to unfold.. There is at all
1 Jones, C. H., Epson, A. W., anD Morse, W. J., The maple sap flow. Vt.
Agric. Exper. Sta. Bull. 103. 1903.
Botanical Gazette, vol. 48] L442
/0 Ta a,
a e
we i
i s
HH.
a aes
Pad
-o
4
SoS cm
/
- ae
—Sap pressure curves for maples and birches April 18, 1904: A, near the base of a 12-inch maple; B, 157°™ above A; C, the
Ma anit D, 180c from the base of 7-inch black birch; F, 135° below D; E shows where the pressure curve of D would
have been if there had been exact hydrostatic equilibrium within the tree; G, curve for a 10° maple; the responses of pressure to sun-
shine and cloud are to be noted
[6061
ftv HONId AHL NI AMASSAAd dVS—NOAT GNV NIMYIW
444 BOTANICAL GAZETTE [DECEMBER
times a very regular distribution of pressure in the birch trunk, taps
at the same height giving like pressures, and taps at different heights
showing most pressure in the lowest. The difference between the
pressure in the lowest tap hole and that in the highest is usually
slightly greater than the hydrostatic difference in level between the
holes (fig. 1).
Pressure in one hole is always immediately and markedly lowered
by sap flowing freely from another hole, even though the holes are
on opposite sides of the tree and many feet apart vertically. This
fact, of course, indicates a free intercommunication among the ducts
of the birch wood. ;
In all of the cases we have observed, pressure began to be evident
at the base of the tree first, and as pressure increased there it showed
itself higher and higher up.
Daily fluctuations of pressure in the birch were reported by CLARK.’
The general character of these fluctuations was brought out by sen)
observations in April 1904. A rapid rise of pressure beginning In
the morning is followed by a slow decline till near sunset, then a
gradual rise is kept up during the night. The nightly rise of pressure
is checked if the temperature of the tree falls below freezing. Changes
of pressure are only slight the next day after a freezing night, unless
the air temperature reaches 40° to 45° F.ormore. (These oscillations
of pressure occupying a period of a day are graphically shown in jig. 3
of the second part of this paper.) ey
The most striking phenomenon of the birch sap pressure is its
variability during those rapid changes of sunshine that take place on
days when cumulus clouds occasionally drift before the sun. ya
have seen the mercury column in a gauge move more than 2-5
vertically in a minute in response to a change of less than 1°C. as
registered by a blackened-bulb thermometer exposed to the sun-
Furthermore, pressure changes of this rapidity have been kept up.
for nearly ten minutes at a time. Fig. 2 is a record for part of an
afternoon in which bright sunshine and dense cloud-shadow -
nated. A drop in pressure of 37-5°™ of mercury during a period ©
cloud-shadow, and a subsequent rise of 30°" when the sun appeared,
took place between 2:30 and 3:20 p.m. A comparison of the bir
? CLarK, W. S., The circulation of sap in plants. 1874.
1909] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 445
with the maple, in respect to pressure and the passing of clouds, may
be made from jig. r. Even the most decided ups and downs in the
_ curve of the birch pressure are scarcely more than suggested by the
slight steepenings or flattenings in the long slopes of the maple curve.
e have always found the maximum pressures in large birches
higher than in small ones. The highest pressures observed in both
large and small trees were on May 2, 1904. A 7.5°™ black birch then
gave a record of g1°™ (1.2 atmospheres), a 17.5°™ black birch of
146°™ (1.9 atmos- pmrzo 2:00 2:40 320 4:00 4:40
Pheres), and a 35°™ =
black birch, about 20™ — Z
high, the astonishing
pressure of 204° V/\ hy ae
(2.68 atmospheres). x
The last pressure
would doubtless have 70
been even greater if it
had been taken two
hours earlier, for both Pr =
he 7. 5°". and « the
17.5°" trees had ) rt Adi ‘Al
already declined more :
than ro per cent. from EY
maximum when the :
large tree was tap ped. Fic. 2.—The intensity of the sunshine as measured
As it is, this pressure by a blackened-bulb thermometer and the concurrent
is equal to 200°™ of pressure, measured in inches of mercury, at the base of
mercury or 27™ of a 35°™ black birch, May 2, 1904.
water, being 1.8™ of water higher than any previously recorded
sap pressure (CLARK, /.c.) Such pressure would support a column
of water 7.8™ higher than the tree. The highest point on the pres-
sure curve of jig. 2 represents this pressure.
Negative tensions occur frequently in the higher parts of the trunk
of the birch, and less frequently near the base. In the latter position
it is only in the early part of the season that suction is kept up for
more than a few minutes at a time. On April 22, 1904, suction pre-
vailed all day in yellow and black birches that had been in states of
446 BOTANICAL GAZETTE [DECEMBER
high pressure on several occasions since April 5. A hard freeze
the night before and a temperature not exceeding 40°F. during
the day seem to have been the chief factors controlling the negative
pressure.
The chief characteristics of sap pressure in the maple
On some warm winter days, at least as early as February 1, sap
will flow in amounts of a few cubic centimeters from tap holes in small
maples that are exposed to the sun; but the maximum flow and cor-
responding pressure do not occur till the ground is thawing in the
spring. At this time pressures in a tree are not distributed with any
apparent regularity. Portions of the trunk at the same level may give
very different pressures, and for different heights the pressure may be
greatest in either the highest or the lowest situation, though usually
pressure decreases irregularly with height (fig. 1, A and B).
Pressure in one tap hole may be but little decreased by sap flowing
freely from another hole a few inches at one side of it, but there may
be a decided drop in pressure if the flow is from a hole a few feet
above or below the hole to which the gauge is attached. From these
facts it may be inferred that the ducts of the maple communicate with
some freedom along the grain of the wood, but scarcely at all across
the grain:
| When pressure begins it may be manifest first either near the ree
or in the branches, but for any given place in the trunk there 15 @
strong tendency toward a daily increase of pressure during the
morning hours, and a decrease during the afternoon. The decrease
often goes beyond zero to a considerable suction (fig. 1, B; after
T:00 P.M.). Size of the tree, situation, and depth of tapping all
affect the character of the daily pressure variation. Small size,
€xposure to the sun, and shallow tapping are all favorable to extreme
and rapid pressure changes. In spite of all the variations already
discussed, there is a tendency toward parallelism of the pressures
developed in different parts of the same tree, and in various tee
during a daily period. The causes of such pressure variations, 4
related especially to daily periods of temperature change, have beet
discussed by various writers.
There is a general agreement that rises and falls of temperature
1909] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 447
of a few minutes’ duration have almost no effect upon pressure in the
maple. The Vermont Bulletin records one instance when a wavy
line given by a recording gauge was probably due to variations in
sunlight, pressure falling slightly when a cloud obscured the sun.
Our record of April 18, 1904, shows conclusively that maples may
respond notably to variations in sunlight. In fig. 1, lines A, B, G
are pressure curves for maples. At 11 A.M. and at 2:00 and 3:35
P.M. the irregularities in the curves were observed to be directly
related to insolation. As to the amount of tension that has been
observed in maples, our highest records were from a'25°™ tree March
12, 1902, 75°", and from a 10°™ tree April 5, 1904, 69°". The
Vermont Bulletin (p. 75) records a pressure equal to 129°" on March
21, 1898. Pressures exceeding 75°™ are only occasionally observed.
Negative pressures seldom exceed 20°".
PART II
H. E. MERWIN
Causes of sap pressure variations in the birches
The studies of Ig06—1908 were carried on in Cambridge, Mass.,
in the hope of getting more data as to the causes of pressure variations
in birches.
The character of both the long and the short period oscillations on
the pressure curve, and the corresponding record of a freely exposed
blackened-bulb thermometer for several days, are shown in fig. 3.
Several important relations are to be noted between the two curves.
During the day there is a close parallelism; at night the pressure curve
rises regardless of temperature. In other words, maximum pressure
and maximum insolation occur at about the same time, near the middle
of the day; but minimum pressure comes near sunset, while minimum
temperature is nearly 12 hours later, shortly before sunrise. Some
of the factors in the control of sap pressure are brought out in the
several experiments and discussions that follow. The details of
the longer experiments referred to in the general discussion are given
under a later heading,
Experiment shows that during the sap season for the birch, all
the intercommunicating cavities of the roots and stem are kept
Practically full of sap. One tree (exp. 1) gave the calculated gas
—
——
ai
Sst
Sy
LA a 1s PMA pt
j Pa Ae
a ‘ i NV ae KE
i [ / iS 7 2 ee Z
a ] as = a 45
— : 35
Fic, 3.—The upper curves are the records of pressure in a white birch t1e™ in diameter; the continuous line covers the period
April eas, inclusive, 1906; and the dotted lines A, B, C, D are partial records for April 14, 23, 28, 30 respectively; after April 18
the pressure was somewhat lower than it would otherwise have been, owing to a continuous slight flow of sap from the tree; the lower
curves are temperatures in the sun; M, midnight; N, noon.
gtr
ALLAZVID TYOINVLOG
aaawaoad]
1909] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 449
content of the vessels as about 1 per cent. of the total volume of the
vessels. This fact easily explains the state of hydrostatic equilibrium
which observation shows to exist in the birch stem when pressures
are high. Increasing pressure must diminish the size of gas bubbles
to a considerable extent by increasing the solubility of the gas in the
sap; decreasing pressure would have an opposite effect.
There is, however, until rather late in the sap season, a good deal
of gas in the closed cavities of the wood fibers. This is shown by
specific gravity tests. A density of 1 is not attained in the wood
of the branches until the buds are about one-third longer than in their
winter condition. The maximum density of 1.14 to 1.17 is reached
when the first leaves are about 8™™ long, near the end of the sap
season. About a month is required for an increase of 25 per cent. in
density. Therefore, the aerial parts of the tree considered in exp. 1,
with an estimated volume of 57,000°°, would require about 500°° of
water as a daily supply from the roots to bring about this increase
in density. |
To get an idea of the amount of water required to maintain evapora-
tion from a tree at the middle of the sap season, two twigs, weighing
T.94°™ and 2.3556%™ respectively, after the cut ends had been
sealed with balsam were exposed for 3 hours, the first to a temperature
of 70° F. in the laboratory, the second to about 42° F. in a breeze.
The first twig lost o.03812™, and the second 0.0256". An average
evaporation of o.o1®™ per hour for a twig weighing 2®™ may be taken,
therefore, as an approximate measure of evaporation from the birch
for the middle of the sap season. The tree of the experiment bore
about 2000 such twigs, from which the evaporation at this rate would
be 480°° of water per day.
This water evaporated from the tree and that absorbed by the
wood fibers during the increase of density of the tree may be taken as
the approximate amount of water supplied to the tree daily by root
absorption.
Inasmuch as pressures are freely transmitted throughout the
birch stem, it is evident that variations in the rate of evaporation and
‘™filiration and of root absorption> will cause variations in pressure.
3 LivIncston (The réle of diffusion and osmotic pressure in plants. 1903) has
the factors concerned in the control of absorption and pressure in roots.
450 BOTANICAL GAZETTE [DECEMBER
It is needless to enumerate the weather conditions which affect the
rate of evaporation, but it is worth while to note at least one chief
factor in the control of root absorption. It is well known that root
absorption is accelerated by moderate increase of ground temperature
above the freezing point. It has been shown by MacDoucats that
ground temperatures in the vicinity of New York City at a depth of
30%" are maximum about 8:00 to 11:00 at night, and minimum
about 8:00 to 10:00 in the morning. At greater depths the maximum
and minimum would occur later, but the temperature variations would
be less marked. Therefore the maximum temperature of the roots
of birches—which lie mostly within less than 60°™ of the surface of
the ground—must occur during the night, and the minimum tempera-
ture during the afternoon. Thus, root absorption and the pressure
produced by it tend to increase at night. In Ciark’s (I. c.) experi-
ments on roots severed from the tree, the rule was for root pressure
to increase during the night and decrease during the day, for the
whole period in which pressure was strong. ;
Taking the combined effect at night of increasing root absorption
and decreased evaporation, there is a decided tendency toward an
increase of pressure in the stem during the night. As the pressure
increases the rate of infiltration also increases, tending thus to dimin-
ish the rate of increase of pressure (fig. 3). After sunrise evaporation
begins to oppose the rise of pressure, so that about noon prey
begins to decline. The decreasing activity of the roots at this time
aids the decline. What pressure might be developed in a birch stem
by the prolonged action of root pressure, if the modifying influences
of evaporation and infiltration could be eliminated, is shown by
C1ark’s record of 193°™ pressure in a birch root severed from the
stem. This pressure is more than double the pressures usually
observed in the trunk. -
Assuming that root pressure is essentially osmotic, the concentra-
tion of the sap in the root CLARK observed must have been about two
and a half times that of the sap at the bases of trees I have observed.
At different times during the sap season, I have evaporated sap ai
birches and found it to contain o. 5 to 1 per cent. of solids, largely
s ther
4MacDoveat, D. T., Soil temperatures and vegetation. Monthly Wea
Review 31:no. 8. 1903.
1909} MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 451
glucose. A sap containing o.8 per cent. of glucose represents an
osmotic pressure of about 78°™ at o° C. It follows, then, that roo°™
of pressure in a birch stem is the maximum to be expected from root
pressure.
Volume changes in the sap and wood due to changes of temperature
in the tree cause marked variations in pressure.
I find that the expansion of sap from 6° to 32° C. is only 2 per cent.
greater than the expansion of water. Cell wall substance, on the
other hand, when saturated with water, expands about 2.2 times as
much as water between 6° and 32°C. (exp. 3).
Observations as to the elasticity to the transmission of light of birch
wood tissue in a thin microscopic section shows that wood fibers
and the walls of the vessels in the wood have the least elasticity
parallel to the length of the stem, and that the medullary rays have
least elasticity along radii of the stem. In a wood fiber the greatest
elasticity is perpendicular to the surface. By comparison with other
substances, in which expansion by heat is directly related to elasticity
to light, a different coefficient of thermal expansion for different
directions would be expected in both single wood fibers and in masses
of wood. My determinations made on strips of green white birch
wood about 500°™ long immersed in water show that between 6° and
32° C, there is contraction instead of expansion in a radial direction
when the temperature is raised. Under like conditions a longitudinal
strip showed at first a slight expansion, but in two subsequent deter-
minations it contracted. The coefficients of radial contraction
obtained were 0.000005, 0.000004, and 0.000006; and those of
Jongitudinal contraction were 0.000002 and 0.000003. These
coefficients are so extremely small that they may be neglected in the
following sap pressure calculations.5 It thus appears that the volume
changes in the cell walls above mentioned are made possible only by
a diminution of the area of cross-section of the vessels and of the
cavities in the cells, for the external dimensions of the tree change
Scarcely at all.
The effect of this tendency to diminish the pore space in the wood
’ The thermal expansion—based upon exp. 3 and upon the above coefficients—
of a given volume of birch wood, of which 4o-45 per cent. is saturated cell wall, amounts
‘6 about 1.5 times the expansion of an equal volume of water.
452 BOTANICAL GAZETTE [DECEMBER
is to produce pressure on the liquid or gas occupying the pores. If
liquid alone completely filled the cavities of the wood, any amount
of thermal expansion would necessarily be accompanied by an equal
amount of elastic expansion of the wood. Pressure in this case might
be very great. It should be noted, however, that the pressure recorded
by a gauge would be less than that developed in the tree without the
attached gauge, for the sap forced from the tree into the gauge would
partly relieve the pressure within the tree. It follows that the less the
amount of sap required to operate a pressure gauge, the higher the
pressure it will record for a given amount of thermal expansion within
the tree.
It probably never happens that the wood of a birch tree becomes
completely saturated with water. One or two per cent., at least, of
gas is present in the wood fibers when the wood is densést. A smaller
amount is present in the vessels. The compressibility of this gas
lessens the effect of thermal expansion in producing pressure.
In order to obtain a quantitative statement of the amount of thermal
expansion, I have made the following estimates. The small white
birch (11°™ diameter) of exp. 1 has about ro per cent. of its volume
in small branches and twigs. These must vary in temperature in the
same way that a blackened-bulb thermometer would, only in a less
degree—say a maximum daily range of 20°C. The trunk would
vary less in temperature than the air—say 10°C. The maximum
daily change of volume of the sap and cell walls of the tree computed
on this basis would be 270°°, or nearly o.5 per cent. of the volume
of the tree. Under such conditions the presence of as little as T Pet
cent. of gas in the vessels would prevent an existing small pressure
from rising more than about 4o°™. The slight increase of pressure
due to the greater expansive force of the gas at the higher temperature
is so small that it may be disregarded.
We may now consider in detail some of the instances 17 5
temperature controls pressure by causing volume changes within the
tree. Fig. 2 is a record of pressure, and of temperature as given by
a blackened-bulb thermometer. The periods of lower temperature
were caused by the passing of clouds. Pressure increased during the
periods of sunshine and diminished during the intervals of shadow-
From 3:00 to 3:20, while the sun shone bright, the temperature of the
in which
19099] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 453
thermometer increased 7° C. The corresponding increase in pressure
was 30°". It is impossible that any part of the tree except the
smallest twigs could have been heated during so short a time more
than 3 or 4°. There must have been, therefore, little or no gas in
the vessels of the tree.
On April 21, 1906, from 2:00 to 2:45 P. M. (fig. 3), a rise of tempera-
ture of 4°5 C. was accompanied by an increase of pressure of 20°".
At sunrise on each of the mornings included in jig. 3 the pressure
curves steepen greatly.
During the afternoon of April 23, 1906 (curve B, fig. 3), the pressure
was rising slowly till nearly sunset in response to a change of the
weather with rising temperature.
From the foregoing discussions it may be reasonably inferred that
there are two chief pressure-producing agencies concerned in the
phenomenon of sap pressure in the birch stem, namely root pressure
and thermal expansion. The effects of both are modified consider-
ably by evaporation and by infiltration of sap into the wood cells. .
Root pressure and evaporation produce a daily oscillation of pressure,
with the maximum shortly after sunrise and the minimum at sunset.
Thermal volume changes in the tree cause a rise of pressure from
sunrise till shortly after midday, and a fall from then till sunrise.
Irregular minor oscillations of short period are caused by correspond-
ing changes in air temperature or brightness of sunshine. The com-
bined effect of the two agencies is to make the observed maximum
come about midday and the minimum at sunset. The maximum
is somewhat higher than would be produced by root pressure alone—
in extreme cases twice as high.
If a tree is tapped when the pressure is high, the flow of sap is at
first copious, but the rate of flow lessens rapidly. The pressure, as
measured anywhere in the trunk, also declines (see exp. 2 and fig. 5).
The relation of pressure to flow during this period of falling is different
for different relative positions of the gauge and the flowing orifice.
Taking a theoretical case, the pressure as distributed over a radial
section of a tree before tapping is represented in A, fig. 4. Lines of
equal pressure are horizontal, and pressure increases downward.
Shortly after tapping at a, the lines of equal pressure are as shown in
B. A little later they are as in C. (The diagrams are constructed
454 BOTANICAL GAZETTE [DECEMBER
for a case in which the resistance to flow of sap is twice as great radially
as longitudinally.)
Now let the rate of flow for the first ten minutes after tapping be
represented by jig. 4, D, curve N, and let B show the distribution of
pressure at the end of two minutes, and C at the end of the 10 minutes.
Let the pressure be measured at the three points x, y, z. The pres-
sure in x before tapping is 40.5°™, at the end of 2 minutes it is 35°",
and at the end of ro minutes it is 25°". These values are plotted in
fig. 4, D, curve X. The values for the pressure in holes y and z are
likewise plotted in fig. 4, D, curves Y and Z. Inspection of these
0
88
Ke]
SE | 0 40 Na
—___ md
: og
40 eae | X
hea Ss
Bs
Fic. 4.—For explanation see text.
20
NP
N
~
a So
T
{
!
!
oO 1
'
/
é
Ss
+ —~~_ J
N Pp ;
A B
curves of pressure and the curve of flow shows that there is no
definite general relation between pressure and flow.
Experiments
EXPERIMENT 1.—During the evening of April 14, 1906, while the
normal evening rise of pressure was in progress, a white birch (Betula
populijolia) 11°™ in diameter and 6™ high was tapped for two gauge
157°" vertically apart. The pressure from the first was more bea
enough to sustain a column of water as high as the tree. The differ-
ence in pressure of the two gauges was 12 to 12.3°™ of mercury; the
hydrostatic pressure corresponding to this difference in the height of
the two gauges being 11.6°™, This hydrostatic equilibrium may be
explained on the supposition that a practically continuous column
of water could have been traced through at least some of the ducts
between the tap holes. Other ducts might have contained bubbles
mn.2 4 6 8 10
1909] MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 455
of gas. That there was a small amount of gas present was shown
by pouring mercury into the free arm of the lower gauge and thereby
forcing back into-the tree 0.45°° of sap. This procedure caused the
pressure within the tree to go up from 54 to 55.3°™. A simple calcu-
lation shows that there was a contraction of nearly x per cent. in the
gas in the vessels. The total volume of gas contracting was then 45°°.
To get an estimate of the amount of duct space in the tree, I
examined several cross-sections of branches about 2.5°™ in diameter.
An area of 1. 25° ™™ contained an average of 74 ducts, with an average
cross-section of o.002°™™, The ducts, therefore, occupy about —
12 per cent. of the volume of the tree. The volume of the tree (esti-
mating the upper 3™ of the stem and branches as equal to the lower
3™ of the trunk) was 57,000°°. The duct space, then, amounted to
about 6800°°. Finally, 45°° (the gas content of the ducts) is nearly
0.7 per cent. of the volume of the ducts. A second addition of mer-
cury gave the gas content as 1.3 per cent. The ducts, therefore, at
this time of the year were almost entirely filled with water. In a
larger tree, in which there is a good deal of heart wood, there might
be considerably more gas in the ducts, but many of the ducts in the
heart wood are probably not freely communicating with the ducts in
the sap wood. ;
It was noticed in connection with adding the mercury to the gauge,
that after the rise of pressure thus produced had taken place, the
pressure remained stationary for 15 minutes the first time, and for 30
minutes the second time, and then began rising at its previous rate.
Furthermore, the length of time that pressure was stationary was
such that during that time pressure would have increased naturally
the same amount that it was artificially raised. We may conclude
from this that the intensity of root pressure was increasing during the
night. This is in accord with the idea that the concentration of the
sap in the roots—and the corresponding osmotic pressure—becomes
greater when evaporation from the branches lessens.
EXPERIMENT 2.—Before sunrise April 16, 1906, when pressure was
high and slowly rising, three holes were bored in a small birch trunk,
about 1.5™ apart vertically. Gauges were attached to the lower
holes and the upper one was plugged. Equilibrium was soon estab-
lished between the gauges, the upper one reading 61.9°™ and the
456 BOTANICAL GAZETTE [DECEMBER
lower one 76.3°™.. The difference (14.4°™) is 2.8°™ more than the
pressure of the sap column between the holes. This is the condition
that would obtain if sap were being artificially pumped into the base
of the stem and were evaporating slowly from the top. Friction of
the sap in the ducts would cause the lower gauge to read higher than
if no current were flowing.
The gauge in the middle hole was then removed ‘and the sap
allowed to flow from the hole. A few minutes later the upper hole
was unstopped, but no sap flowed from it, though sap had flowed from
it when the hole was made. The flowing of the hole below it had
caused it to cease to flow. As soon as the middle hole began flowing,
the pressure in the lower hole dropped rapidly to 23.4°™, and there
remained nearly stationary for over an hour. The total drop in
pressure in the lower hole was thus 52.9°™, but in the hole above the
drop was 61.9°™. In other words, the pressure in the lower hole
was 11.8°™ more than enough to raise sap to the level of the flowing
hole. This, also, is a condition to be expected if a current of sap was
flowing upward from the roots through the stem, overcoming friction.
The flow from the middle hole was at first rapid—z7 drops in
ro seconds—but it decreased in a few minutes to 8 drops per 10
seconds, and at the end of 20 minutes to 4 drops. The flow then
- continued at nearly this rate for more than an hour. Curves 4 and
B, D and E, of jig. 5 are plotted from these observations. Curve C
shows the drop of pressure from a similar experiment on another tree.
Although the curves are nearly parallel, the ratio of flow to pressure 1s
greater for the highest pressure than for the lowest. This relation
may be explained by assuming that the copious flow of the first few
minutes had a double source of supply; the larger part came irom
the trunk, being forced toward the tap hole by the elastic expansion
of the wood and the gas in the wood; and the smaller part came as a
current from the roots. As soon as the excess of pressure in the stem
had been relieved, the further and nearly uniform flow was kept up by
the root pressure. Changes in the degree of cloudiness produced
the waviness of the curves C, D, and E in jig. 5.
During the 20 minutes that the flow was decreasing 790 drops
(66°°) of sap escaped. Of this not more than 40° or less than 25
could have come from the roots. (This will be seen by a study of
1909} MERWIN AND LYON—SAP PRESSURE IN THE BIRCH 457
curve B.) Therefore, 32°° is close to the amount supplied by the roots
and therefore about 34°° came from expansion within the tree. The
experiment of two days before showed the amount of gas in this tree
to be 45 to 80°°, an amount which, by expansion, is sufficient to
account for the flow here considered.
20
‘ 5:25 6:05 6:45 7:25 AM
\ it
>
%
‘
Sects
oe ore
; a oe
™S
\ :
SS 3
x => —— 2 B
——+$_ —__-— ot Re ae A
a
=
9 min, 10 20 30 40 50
Fic. 5 —A, pressure ay the base of a white birch, April 16, 1906, while flow was taking place from a hole
ff up; B, rate of flow in drops per minute of the hole above A; the continuation of curves A and B are D
a in another tree the decline of pressure while sap was flowing freely is shown by C
EXPERIMENT 3.—To determine the amount of expansion of
saturated cell-wall substance of birch wood.
Across the grain of a white birch plank thin shavings were taken.
From these the air was entirely expelled under the receiver of an air
pump. The shavings were then transferred to a 100°° pycnometer.
The pycnometer was filled up with freshly boiled, distilled water, and
weighed at 6° C., and again at 32° C. The weight of the pycnometer
458 BOTANICAL GAZETTE [DECEMBER
full of water alone was also taken at these temperatures. Finally
the weight of the completely dried shavings was found. Now the
specific gravity of dry cell wall substance is approximately 1.56, and
the volume of saturated cell wall substance is nearly 3/2 that of dry
cell wall substance. Then let a=increase in weight of pycnometer
full of water from 32° C. to 6° C.; 6=increase in weight of pycnometer
full of water and shavings from 32° C. to 6° C.; c=increase in volume
of pycnometer from 32° C. to 6° C.; d=volume of pycnometer;
e=volume of saturated cell wall substance; o.0046=expansion of
1°° of water from 6°C. to 32°C. Then
b+c—(d—e) (+)
e€X0.0046
= the ratio of expansion of cell wall to the expansion of water from
6° C. to 32°C.7 Now, by substituting the values obtained in the
experiment,
; : +0.066
0.4975 +0.066—(r00— 12,6) (2-438 +2:28%)
=2.2
12.6X0.0046
=the desired ratio of expansion.
PETROGRAPHICAL LABORATORY
ARVARD UNIVERSITY
}|
© These are the figures given a Sacus, Hartic, and others, and used in comp —
the tables of the Vermont Bulleti
7 This formula would need a corrections for more exact work, ad “
accurate than the factors of specific gravity and volume of saturated cell wall.
is more
BRIEPER ARTICLES
CONCAVITY OF LEAVES AND ILLUMINATION
(WITH ONE FIGURE)
Concavity of the upper surfaces of leaves is of extremely common
occurrence among the higher plants. WIESNER, in an important paper,’
has discussed this concave upper leaf surface as a characteristic of the
peripheral leaves of woody plants, and states that the leaves within the
shadow of the crown of trees (with concave outer leaves) are generally
flat or nearly so. He classes these and other leaves which are capable of
Fic. of cross-sections of leaves, taken at right angles to the midrib
(if there is cae cau through its middle point. #. a, Astilbe decandra; b, Prunus
persica; c, Syringa vulgaris; d, Akebia quinata; e, Citrus medica; /, Styrax japonica;
g, Begonia semperflorens; h, Schizophragma hydrangeoides.
some kind of temporary or permanent adjustment to the amount of light
received as panphotqmetric leaves, regarding the concavity as useful in
preventing injury to chlorophyll by excessive sunlight. OLTMANNS? calls
attention to the fact that the leaflets of Robinia Pseudo-Acacia are concave
on the south sides of trees, but flat on the north sides.
It seemed to the writer worth while to make some notes as to the occur-
rence of the concavity in question among various genera, particularly among
trees and shrubs, and to take a few measurements of the amount of con-
t WIESNER, J., Anpassung des Laubblattes an die Lichtstarke. Biol. Centralbl.
I-15. 1899.
2 OLTMANNS, F., Photometrische Bewegungen der Pflanzen. Flora_79:232, 233.
1892.
459] {Botanical Gazette, vol. 48
460 BOTANICAL GAZETTE [DECEMBER
cavity in shaded and unshaded leaves of the same individual. Most of
the species observed were growing in the Botanic Garden of Harvard
University. No attempt was made to pick out particular families for
examination, but notes were made on any leaves, especially of dicotyledo-
nous trees or shrubs, that showed decided concavity of the upper surface.
Some slight amount of deviation from flatness seemed almost universal.
The observations were made on mature vigorous leaves during the first
week in September.
The leaves or leaflets examined in many instances showed a rather
definite dihedral angle, as in a and 3, fig. z. More often the surfaces on
each side of the midrib were decidedly curved, as in the cases c-f, while
some leaves, as in g and h, showed no semblance of an angle in the cross-
section, but formed a rather deep trough, with curved sides.
Measurements of angles were made by means of two straight-edged
pieces of brass, hinged at one end and applied outside the leaf or leaflet at
right angles to the midrib. In case the leaf surfaces were somewhat convex
beneath, the angle taken was that subtended by a tangent to the middle
points of the halves of the leaf.
Plants of 31 families of dicotyledons, comprising 52 genera and pos-
sibly 200 species, were noted as showing decided concavity of the upper
surfaces of the leaves. Little attempt was made to find out how generally
marked leaf-concavity characterized the various species of the genera
examined. In some instances, e. g., Viburnum, it occurred in almost all
the species accessible for observation, while in other cases, e. g-; Magnolia,
Acer, it was present in some species and absent in others. « e
The following measurements of dihedral leaf angles or concavities
were obtained:
Species Angle in degrees, | Angle in degrees, shade
Akebia quinata (leaflets).............. 106 167-180*
Magnolia acuminata.........4........ 80-180 | 180 or recurved
Astilbe decandra (leaflets)............. 80-153 180 or recurved (167)
Hydrangea quercifolia................. 134-180 180 or less
chizophragma hydrangeoides......... 28-1 180 or less
Fothergilia Gardeni.. <5 2. 34 80-180 180 or less
Robinia Pseudo-Acacia (leaflets)....... 90-137 180*
Begonia semperflorens................ 23-50 108-180
Aralia pentaphylla (leaflets)........... often semicircular 180
Ligustrion Thota. occ. iene be 5 180
Syringa vulgaris........... Sar SipaeeeA 55-145 130-180
Cephalanthus occidentalis............. 102-153 180
Viburnine mite. soso 83-105 180
eee OLS
* The chade] n Ve Nice ee a eee 1 by the foliage of the plant itself.
en ee a wall
In the tu. Lod 1 Pipes oe ee | 1
1909] BRIEFER ARTICLES 461
It is undoubtedly a fact that the great majority of woody dicotyledons
have leaves which when freely exposed to the sun are concave on the upper
surface and that this concavity usually lessens or disappears in the case of
much-shaded leaves on the same plant. WIESNER’s conclusion that this
conformation is due to the effects of powerful illumination seems on the
whole to be plausible. It is not safe, however, to assume, as he does, that
we have here an undoubted case of protective adaptation, to ward off the
injurious effect upon chlorophyll of excessive insolation. In order to prove
this it would be necessary to explain many real or apparent exceptions to
the assumption that greater concavity should go with greater illumination.
To cite the first instances that occur: Acer Negundo is hardly, if at all,
more exposed to excessive sunlight in its usual habitats than is A. sacchari-
num, and yet the former has trough-like leaflets, while the leaves of the
latter are nearly flat. The Japanese Ligustrum Ibota comes from a region
not enough more subject to excessive sunlight than that of the European
L. vulgare to account for the great difference in the flatness of the leaves of
the two species. Vinca rosea, a West Indian weed, might be expected to
have leaves much more concave than those of the European V. minor,
but the reverse is actually the case. Occasionally leaves growing in shade
may be decidedly more concave than those growing under greater illumina-
tion, as I have noted in one case of Kalmia angustifolia. Finally, it is
difficult to explain on any theory of utility of concave leaf surfaces in protect-
ing chlorophyll the fact that the angular values obtained for leaves of the
same individual, grown under similar conditions, vary somuch. The angles
given in the preceding table for each species were in many instances obtained
from leaves which apparently received almost identical illumination, since
they grew fairly near together and were sometimes almost in contact
with each other. Yet, as will be observed, the angles for sun leaves some-
times varied in a ratio as high as six to one. Equally difficult to explain is
the fact that in some genera, e. g., Prunus, Pyrus, Salix, the whole tree
may show little difference in the flatness of the leaves, all being angled
whether they grow in sun or shade.
Instead of trying, as WIESNER has done, to establish the critical intensity
of illumination at which leaves of a given species cease to be panphotometric
and become euphotometric, it would seem to the writer better worth while
to look for some relation (always on the same individual) between illumina-
tion and the average amount of angular divergence of the halves of the
leaf, basing all statements on a large number of measurements.—JosEPH
Y. BercEn, Cambridge, Mass.
462 BOTANICAL GAZETTE [DECEMBER
ROEZL AND THE TYPE OF WASHINGTONIA
The palms on which WENDLAND founded his genus Washingtonia were
grown from seed procured by RoEzL. They purported to have come from
“Nord Mexico, bei Arizona, am Rio Colorado,” but where they really came
from has never been ascertained. In investigating the history of the genus
it proved very difficult to obtain any account of Rorz’s American explora-
tions. I was able to learn only of a journey made by him across the north-
ern continent in 1872, and was therefore led to assert? that this was his only
visit to our country. In fact, however, he had made a far more extended
tour in 1868-1870, in the course of which he explored much of the United
States and Mexico, and of Columbia in the southern continent. Some
account of these journeyings is given in notes published by ORTGIES in
volumes 20 and 23 of Gartenflora. Dr. TRELEASE, director of the Missouri
Botanical Garden, has obligingly furnished me with an abstract of these
notes, and from them I am able to present the following account of ROEzL’s
explorations in the United States.
OEZL must have gone from Europe directly to Mexico, and he spent
the winter of 1868-1869 in collecting in that state and in Yucatan. In
March of the latter year he sailed from Havana for New York. He then
visited several of the seaboard cities and made some collections in the Alle-
gheny mountains, after which he departed for the west by way of St. Louis,
Chicago, and Omaha. On July 15, 1869, he was in Cheyenne, and *
August 28 in Truckee. Considerable time was devoted to collecting 17
Utah and Nevada, but by November 7 he had reached San Francisco, by
way of Sacramento. After a run back to Nevada City he returned to San
Francisco, and went thence to San Diego. The object of his southern trip
was to gather Delphinium cardinale, and he sent to Europe two thousand
roots that he supposed to be of that species. Eventually, on flowering they
proved to be one of the blue larkspurs, probably D. Parryi. Here also he
got two plants which were introduced to European cultivation as Yucca
schidigera and Y. Ortgiesiana, unquestionably the species now known 4s
Yucca mohavensis and Hesperoyucca Whip plei.
Roezz returned to San Francisco in time to sail on January 18, 1870,
for Panama, and after g extensi llections in Columbia and Mexico,
again reached San Francisco August 1, 1870. PAs
After a week spent in Hoopa Valley, he sailed for the north, visiting
3 Bor. GAZETTE 44:414. 1907. Footnote ro on this page should be —
follows: dele 1889: 330; for Jour. Bot. 1874: read 1884:; for Gard. Chron. 2+5
1889 read Gard. Chron. N.S, 24:521. 1888.
1909] BRIEFER ARTICLES 463
Astoria, Portland, and Ft. Vancouver. In September he was among the
mountains of the upper Columbia River, but by October he had returned
to the Sierra Nevada of California. It does not appear when he finally
left California, but by the middle of December 1870 he was again in
Panama. ‘The first two months of the new year were devoted to revisiting
Columbia, after which RoEzz returned to Europe.
It appears from this account that the only opportunity which RoEzi
had of procuring seeds of Washingtonia was during his visit to San Diego,
in December 1869. The notes, however, contain no reference to this palm.
But a visit to any of its desert habitats would certainly have been an experi-
ence too notable to have failed of record. Nor is it probable that his visit
to San Diego, so short and so diligently occupied in collecting, could have
afforded time for the difficult journey to the desert. The vague and con-
fused habitat assigned to the palm is itself a sufficient evidence that the
collector, from whom the information must have come, could never have
visited a native grove. It is safe to conclude that the seed he sent to Europe
came from some of the older cultivated trees at San Diego, and that his
pardonable ignorance of local geography prevented him from correctly
understanding what was told him of the location of the indigenous groves.
—S. B. Parisn, San Bernardino, Cal.
~ LONGEVITY OF SEEDS
In the Botanica, GazeTTE for January 1909, p. 69, CROCKER, in
referring to my paper on this subject, concludes with the remark: “I
believe I am doing the author no injustice when I say that it is impossible
to tell from his paper in how far it is a contribution and in how far a com-
pilation.”” May I say that the utmost care was taken to quote the authority
for every record or fact that was not original, and that I am unable to find
a single case in which this was not done. If any such omission occurs it is
a purely accidental one, and I am prepared to offer both a public and a
Private apology to any author whose name is omitted as the authority
for a record for which he is responsible. Naturally, however, if on repeating
a test or experiment a more or less divergent result is obtained, the original
authority can hardly be given for the changed statement of fact, which in
many cases directly negatives the original record. The latter, however, Is
given in all cases with the author’s name appended, so that it is difficult to
see any foundation for CROcKER’S criticism.—ALrreD J. Ewart, Uni-
versity of Melbourne.
464 BOTANICAL GAZETTE [DECEMBER
REJOINDER
In spite of Ewart’s very energetic objection to my criticism of his
paper, I maintain that the criticism is entirely justifiable. To escape
personal bias I have asked several persons to read passages of EWART’s
article and to say who contributed the data. In every case they decided
that they were Ewart’s, though this is not the case.
As an example, I cite the first part of the paragraph beginning at the
foot of p. 197, dealing with Plantago major, P. Rugelii, Thiaspi arvense,
and Avena fatua. The data are all given in my article,4 but one would not
know from Ewart’s statement that this was their source. Again, in the
paragraph beginning near the top of p. 192, EwArT gives the arguments
against FISCHER’s conception of the cause of delayed germination in the
seeds of water plants as if based on his own work. All these arguments
are given in another paper of mine,’ issued five months before Ewart’s.
In the same paragraph, he says: “‘Since the above was written, CROCKER
(Bot. GazETTE 1907, 374) has shown, etc.’”? One would have expected a
writer who is so careful to give credit where it belongs to recast this para-
graph after he discovered my article, so as to indicate proper priority. I
mention these as two instances out of several that furnished the basis of
my criticism.
Ewart speaks again of his results contradicting mine in a number
of cases. I must therefore point out again that the matters in dispute are
minor details and not cardinal principles in- the physiology of delayed
germination; and I should be glad to have anyone compare his paper and
my criticism to judge in how far there is evidence that his results disprove
mine. I have repeated the experiments upon the disputed points, and have
had various competent students do so independently. The results in every
case agree with my previous conclusions, as my criticism points out.
I am sorry that what I considered and still consider a fair criticism has
led to undue publicity. I am sure, however, that neither a public nor a
private apology is necessary from Ewart, as the case will rest upon ”
merits.—WILLIAM Crocker, The University of Chicago.
4 Crocker, W., Role of seed coats in delayed germination. Bor. GAZETTE
42: 282-284. 1906.
5 , Germination of seeds of water plants. Bot. GAZETTE 44 2375-380
Igo7.
CURRENT LITERATURE
MINOR NOTICES
Malayan ferns.—This work" presents in a single volume a synoptical treat-
ment of all ferns known to occur in the Malayan Archipelago; its elaboration
has been carried on mainly at Buitenzorg, where the facilities for studying dried
and living material of this group of plants are exceptionally good. A compendium
of the families, tribes, and g introd the body of the work; and the sequence
of families, the limitation of genera, and the nomenclature are for the most part
in accordance with ENGLER and Prantt’s Natiirlichen Pflanzenfamilien. Fairly
concise and clear keys precede the carefully drawn descriptions whenever the
genus consists of two or more species, and the bibliography and synonomy are
given in some detail; but it is unfortunate that the author has cited so few exsic-
catae. The extended spacing and the numerous blank pages make the volume
unnecessarily bulky. Moreover, the appendix of some 58 pages, treating princi-
pally of ferns discovered affer January 1, 1907, and 11 pages of ‘‘additions,
modifications, and corrections” which the author suggests “may be cut out and
pasted on the places indicated” will mar materially the practical use of the work.
It would seem almost as though publication might better have been delayed until
such necessary additions and corrections could have been incorporated in the
body of the text. On the whole, however, the work represents careful co'lation,
combined with a large amount of original research, and presents in available and
reliable form a comprehensive treatment of approximately 1500 species and
numerous varieties, representing 10 families and 95 genera. T. he book doubtless
w ll find a useful place in the taxonomic literature of ferns.—J. M. GREENMAN.
Warming’s Ecology of plants. A correction.—My attention has been
called to an unfortunate error in my review of Warminc’s Ecology, viz., the
statement that the work was written in English by the author, assisted by Dr.
As a matter of fact the work, as it has appeared, is a translation by
Professors BALFouR and Groom from manuscript prepared by Professor WARM-
inc and Dr. Vant. My mistake was due to the statement on the title-page:
‘prepared for publication in English by Percy Groom,” etc. (which might have
been less vague if printed: “translated from manuscript,” etc.), and by a personal
knowledge of Warmino’s facility in the English language. It is certainly scant
«VAN ALDERWERELT VAN RosENBURGH, C. R. W. K., Malayan ferns. Hand-
book to the determination of the ferns of the Malayan Islands (incl. those of the Malay
Peninsula, the Philippines, and New Guinea). Royal 8vo, pp. xl+ 899+ 11. Batavia:
n kkerij. 1908.
2 Bor. GAZETTE 48: 149-152. 1909.
465
466 BOTANICAL GAZETTE [DECEMBER
enough credit to a translator to acknowledge his full share in such a work as this,
a share that is most burdensome, and too little appreciated as a rule. Englis
and American readers are certainly most grateful to Professors BALFouR and
Groom for making accessible not only this new ecological treatise, but the other
great ecological masterpiece as well, Scummper’s Plant geography.—H. C.
COWLES
Pharmakognostischer Atlas.—Kocu> has followed his Mikroskopische
Analyse der Drogenpulver with a second part for the use of apothecaries, whole-
sale druggists, sanitary officials, students of pharmacy, etc. In the arrangement
of the text the author has followed his old scheme of different types, numerals,
and indentations for greater facility in locating the various histological structures.
and detailed descriptions of the individual tissues. Excellent plates of trans-
verse and longitudinal sections serve to make these descriptions remarkably
clear. The first Lieferung is devoted to cascarilla, red cinchona, and cinnamon
barks. The complete work will certainly be useful in the recognition of crude
drugs.—K. G. BARBER.
Methods in microscopy.—The second edition of the Praktikum of Mosrus*
has about the same scope as the first. Directions are given for making prepara-
tions and also for some study of the preparations. Only the simplest methods are
given, no attention being paid to the paraffin method or to critical methods of
staining; in fact, most of the directions, in American schools, would be given
orally or would be written on the blackboard for elementary classes which have
no need as yet for any complicated technic. Of the 123 pages, 92 are devoted to
spermatophytes, 6 to pteridophytes, 5 to bryophytes, and 20 to thallophytes.
—CHARLES J. CHAMBERLAIN,
NOTES FOR STUDENTS
Genetics.—In the fourth report to the Evolution Committee of the Royal
Society, BATESON, SAUNDERS, and PUNNETTS present an account of their further
studies with poultry, sweet peas, and stocks. Valuable summaries are gt
all the studies that have been made on these subjects, the most interesting a
being the further evidence of the occurrence of such ratios as 7:1:1:7 and 15:1+1:
15. It is suggested that the types of gametic coupling evident in cases of this
kind might explain the occurrence of certain aberrant forms which are generally
‘looked upon as mutants. The term “spurious allelomorphism” is proposed
yen of
3 Kocx, Lupwic, Pharmakognostischer Atlas. I, Die Rinden. I Bd. 1 Lief.
pp. 26. pls. 5. Leipzig: Gebriider Borntraeger. 1909. M 3.59. -
Mostus, Martin, Botanisch-mikroskopisches Praktikum fiir Anfanget. Seco
4
edition. 8vo. pp. ii+123. Berlin: Gebriider Borntraeger. 1909. M3-20
5 BaTEson, W., SAUNDERS, Miss E. R., AND Punnett, R. C., es gies
studies in the physiology of heredity, Reports to the Evolution Committee of
Royal Society 4: 1-40. 1908. :
1909] CURRENT LITERATURE 467
for the phenomenon of repulsion between two dominant factors or units, as for
example when blueness and the erect standard in peas cannot be combined in the
same individual, but are found to repel one another. The further work with
stocks has mainly had reference to the phenomenon of doubling. The doubled
Stocks are always completely sterile and cannot be used for breeding purposes,
so that it is not easy to determine the significance of this phenomenon. It is
found that single stocks are of two kinds, one of which breeds true to the single,
the other of which always throws a certain proportion of doubles when mated with
its own kind, and the conclusion is drawn that this second type of single stock
is perhaps a heterozygote in which the single character is dominant to the double.
In stocks a difference is also found in the constitution of the pollen grains and ovules
on the same plant. The presence and absence hypothesis is definitely accepted,
and Miss DurHam® in another paper appended to the report shows that on
basis of ‘presence and absence,” the difficulties which Cuénor had found in
certain mouse crosses completely disappear.
In a discussion of the ‘‘presence and absence” hypothesis the reviewer? has
shown that the absence of a character may be dominant over its presence quite
as well as the reverse. A simple experiment to illustrate this among the other
Salient features of Mendelian inheritance has also been described.®
He has also published the results? of his investigation into the elementary
species and hybrids of Bursa Bursa-pastoris and B. Heegeri, showing that the
leaf characters of four elementary forms which were found in nature behave in
the typical Mendelian fashion on crossing with one another. The same relation
is found to exist between B. Bursa-pastoris and B. Heegeri that exists among the
several elementary components of the former species, thus giving new proof of the
derivation of the latter species from the former. However, the Heegeri type of
capsule which disappears in the first generation of the hybrids reappears in the
second generation in a ratio of about 22:1. The important feature of these
results for evolution is the fact that four pure-breeding elementary species of B.
Heegeri resulted from the cross, when only one had been found before.
Correns'° has studied variegation and yellow-green foliage in Mirabilis,
Urtica, and Lunaria, in which he shows that the yellow-green form, which he
—_——
® DurHaAM, FLORENCE H., A preliminary account of the inheritance of coat-color
in mice. Reports to the Evolution Committee 4:41~63. 1908.
7 SHULL, G. H., The “ presence and absence”’ hypothesis. Amer. Nat. 43:410-419.
Tgog
§—-——_ A simple chemical device to illustrate Mendelian inheritance. Plant
World 12:145-153. 1909.
9——_, Bursa Bursa-pastoris and Bursa Heegeri:
Carnegie Institution of Washington, Publ. 112. pp. 57. igs. 23- pls. 4
10 CorRENS, C., Vererbungsversuche mit blass (gelb) griinen sii Sel ae
Sippen bei srabilie Jalapa, Urtica pilulifera, und Lunaria annua. Zeitschr. Abstam.
Vererb. 1: 291-329. figs. 2. 1909.
sted = hybrids.
468 BOTANICAL GAZETTE [DECEMBER
calls chlorina, and the white-margined variety or albo-marginata are Mendelian
in their hereditary behavior, both these forms being hypostatic to green and the
chlorina hypostatic to albo-marginata. Two variegated varieties of Mirabilis
Jalapa, on the other hand, give quite unexpected results. It appears that the
offspring is more or less dependent upon the character of the particular branch
upon which the seed was produced. Baur‘ has found a similar behavior in the
white variegated Pelargonium; thus the offspring of a pure white branch gives
nothing but pure white seedlings which are incapable of successful growth, while
the offspring of pure green branches produce only pure green seedlings. PAUR
goes into the anatomy of the white-margined varieties, and shows that there is a _
complete chlorophylless sheath overlying the chlorophyll-bearing tissues, and
extending beyond them at the margin. Baur’s theory for the production of such
variegated varieties is that the yellow and chlorophyll-bearing plastids are dis-
tributed into the two daughter cells at each cell division, and by chance occasionally
only nonchlorophyll-bearing plastids are included in one of the daughter cells.
Thereafter this white cell gives rise to a cell progeny containing no chlorophyll
and thus forming a white patch or streak which is the product of this one cell.
When the division is anticlinal the variegation is in blotches, and when periclinal
the white tissue becomes either median or marginal, only one case of the median
type having been observed. Baur’s results seem to indicate that the male germ
cells, as well as the female, contribute characteristic plastids to individuals pro-
duced by their union, but this has not yet been actually observed. ‘
The possibility that different parts of a plant may present different hereditary
qualities, as shown by Correns and Baur in these variegated varieties and as
very generally recognized in the case of the relatively infrequent vegetative muta-
tions known as bud-sports, is considered a matter of considerable importance by
De Loacu,?? who seems to have found that in certain cotton hybrids some cap-
sules of the heterozygote have the characters of the one or the other parent pract:
cally “fixed,” while others give a large degree of splitting. Such suggestions 4S
this open up interesting fields for investigation, but theoretically it does not
seem likely that different parts of the same individual plant can generally have
its own special type of heredity.
EMERSON‘3 brings together the work that has been done in the study of
Mendelian characters of beans, and finds that all evidence now at hand supports
the reviewer’s statement that in certain varieties of beans a unit character for
mottling is present, which produces an external manifestation only when in the
tt Baur, E., Das Wesen und die Erblichkeitsverhiltnisse der “ Varietates albo-
marginatae Hort.” von Pelargonium zonale. Zeitschr. Abstam. Vererb. 1:330-35"
Jigs. 20. 1909.
2 Dr Loacu, R. J. H., The Mendelian and DeVriesian laws applied to cotton
breeding. Georgia Experiment Station, Bull. 83: 43-63. figs. 7: 1908. :
3 Emerson, R. A., Factors for mottling in beans. Annual Report Ame ee
Breeders’ Association 5: 368-376. 1909.
1909] CURRENT LITERATURE ; 469
heterozygous state. EMERSON concludes that there are two distinct and unrelated
units for mottling, one of which is a typical Mendelian dominant, the other
becoming evident only in the heterozygous state, and on this basis he works out
the expectation of various types of crosses. It remains to be demonstrated by
actual breeding that such peculiar ratios may exist as 11:5, 21:38, 33:15, 16, etc.
A number of more or less popular expositions of Mendelism have appeared,
and it is not necessary to mention these except in case new scientific matter has
been used by way of illustration. One of the best of these general discussions
is that of BAur,"4 in which the illustrative material is almost entirely derived from
his own experiments with Antirrhinum majus. In this species 15 or more differ-
ent hereditary units have been demonstrated, and the author inclines to the view
that much of so-called fluctuating variation is really Mendelian splitting of less
prominent unit characters. The number of demonstrated units in this species
exceeds the number of chromosomes, which leads the author to the conclusion
that whole chromosomes cannot be the units upon which these characters depend.
AUR adheres strictly to the presence and absence hypothesis. SPILLMAN,'S
in a review of Baur’s paper, shows that so far as yet demonstrated the individual
chromosomes may be the fundamental bases of these unit characters, although
several instances are known in which the number of demonstrated unit characters
in a species is in excess of the known number of chromosomes. The crucial
test must be the finding of an individual having more independent characters
than sy has chromosomes. This has not yet been done.
6 has once again repeated one of MENDEL’s original experiments
in order to determine whether there is any influence of pre-parental ancestry upon
the offspring, a question involving the essential difference between the Mendelian
and Galtonian conceptions of heredity. It was well that this experiment should
be undertaken by one who was in the beginning a staunch Galtonian. The
result of the t leads DARBISHIRE to the conclusion that ‘‘there is nothing
like ancestral cuatiation within the limits of a single unit character,” or in
other words that segregation is perfect and the recessive character appears in as
large a proportion of the offspring of a heterozygote after six generations of selec-
tion to the dominant character as in the F,.
The Mendelian theory of heredity has produced a very deep impress upon
the practical work of plant and animal breeding, and a considerable number of
papers have appeared from economic sources which present valuable a Olly
data in support of this theory, and indicating the extent of its applicability.
a few of the more important of these papers can be noted here. Besides the sade
™4Baur, E., Einige Ergebnisse der experimentellen Vererbungslehre. Beih.
medizinischen Klinik 4: 265-292. 1908.
»sSprttman, W. J., The nature of “unit” characters. Amer. Nat. 43:243-248.
T909.
6DarpisHire, A. D., An experimental estimation of the theory of ancestral
contributions in heredity. Proc. Roy. Soc. London B 81:61-79- 1999-
470 BOTANICAL GAZETTE [DECEMBER
of Dr Loaca already mentioned, which shows that Mendelian behavior occurred
n a certain cotton hybrid, BAtts'? has discussed cotton hybrids in a compre-
Sainte way, showing that at least 21 characteristics of the cotton plants behave
as unit characters. BALLs declares that, while he does not know the exact num-
ber of chromosomes in the cotton nucleus, there are certainly not over 20, thus
placing cotton with Pisum and Antirrhinum, as species in which the number of
known unit characters exceeds the number of chromosomes. Surtont® has
carried on extensive crossings in Brassica and found that in a cross between the
Swede turnip and the Ragged Jack kale there is a strict Mendelian behavior
in which two unit characters are involved, namely, the fleshy character of the
root and the curled leaves. The ratio of 9:3:3:1 appeared very clearly in the
reciprocal hybrids of the cross. The glabrous-leaved brassicas (B. oleracea and
its allies) would not cross with the hispid-leaved species (B. rapa, B. campestris,
etc.), and crosses between the turnip and Swede turnip were sterile.
Nitsson-ERLE’? maintains that practically all of the supposed mutants if
not all which have been found in wheat, oats, and other similar grains split after
the Mendelian fashion, and are in reality the results of occasional cross-fertili-
zations, i.e., of “vicinism.’”’” The most important result reported by NILSSON-
EHLE is the finding of several instances in wheat and oats, in which apparently
identical external characters are produced by the presence of two or more inde-
pendent units, thus resulting in the F, ratios 15:1, 63:1, and perhaps 255:1
(observed ratio 274:1). In following generations some plants from crosses which
showed 15:1 in F, give ratios of 3:1, and others again 15:1. Ina red- grained x
white-grained wheat, which presented the ratio of 63:1 in F,, some plants in F;
gave again the ratio of 63:1, some 15:1, and some 3: 1, thus confirming the author’s
conclusion as to the manner in which the ratios 15:1 and 63:1 arise, and showing
them to be typically Mendelian. The ligula of oats was absent in only one variety
used in the experiments. This crossed with numerous other varieties sare
ratios 3:1, 15:1, 63:1, and in one case apparently 255:1 (actually 274: 1), in
different crosses. He concludes that his results prove the correctness of the
presence and absence hypothesis, and that not a single fact among his crosses is
opposed to the ‘‘purity” of the gametes. He also, like Baur, would explain
the inheritance of certain apparently fluctuating characters as due to Mendelian
splitting of units having similar functions.
17 Batis, L., Some aa aspects of cotton breeding. Ann. Rep. Amer.
Breeders’ Assoc. 5:16-28. 1909
18 Sutton, ARTHUR W., Brassica crosses. Jour. Linn. Soc. Bot. 38:338-349
pls. 12. 1909.
19 Nirsson-Ea ze, H., Einige Ergebnisse von Kreuzungen bei Hafer und Weizen.
Botaniska Notiser 257~294. 1908.
Kreuzungsuntersuchungen an Hafer und Weizen. pp. 122. 199%
Lund: ‘Hakan Ohlssons Buchdruckerei.
1909] CURRENT LITERATURE 471
East’? finds that dent and flint corns differ from one another in a considerable
series of correlated characters, and that these combinations of characters are
maintained when these types are bred with the sugar corns. Although je flint
or starch character of the grains is not then visible, breeding tests show that one
or the other of these is latent, so that there is a ‘‘flint” series of sugar corns and a
“starch”? series.
So far as evidence goes at the present time, the Mendelian method of behavior
is most clearly present in crosses between the most nearly related forms, and
shows the most decided tendency to break down in the crosses between more
distantly related things. For this reason all studies of the behavior of species-
hybrids become of the greatest importance. Hurst?* has made a survey of
orchid hybrids with special reference to the inheritance of albinism, and finds the
phenomena so similar to those already worked out in sweet peas and stocks that
he is convinced that they present typical Mendelian segregation. Lock’? gives
a report on some spccies crosses of the genus Nicotiana. This is only a prelimi-
nary report and many points remain to be cleared up. He finds that the second
generation of some of these crosses shows a wide range of distinct types, which he
believes can be analyzed on the same basis as the sweet peas and stocks have been.
Color of pollen and of corolla, and form of corolla tube (bulged or funnelform)
showed typical segregation. In many characters pertaining to general habit,
leaf form, etc., segregation was not present or only doubtfully. Lock suggests the
possibility that “‘true-breeding” hybrids may result from the failure of any but
homozygous combinations, this idea being made possible by the fact that very
often the fertility of such hybrids is very low, so that but a small percentage of
successful seeds is produced. This matter of non-splitting hybrids between
species has also been presented by BuRBANK,?3 who points out that this presents
a method of production of new species, probably more important than usually
supposed. Although several of the instances mentioned by BuRBANK have
not been sufficiently tested, there can be little doubt that the species-hybrids
in Rubus present cases of this kind. Upon these exceptional situations the chiet
attention of experimenters shou!d be concentrated.
Another hopeful direction for research that is being taken up in several quarters
is that of making analyses to determine the exact nature of the unit characters.
Only in this way can we hope to discover the nature of the character-producing
= ia E. M., A note on the inheritance in sweet corn. Science N.S. 29: 465-467.
21 Hurst, C. C., Inheritance of ess in orchids. Gardeners’ Chronicle. Feb.
6, 1909.
22 Lock, R. H., A preliminary survey
the Mendelian standpdint Ann. Roy. Bot. Gard. Peradeniya 4: 195-227. pls. 12.
1909.
*- the genus Nicotiana from
23 BURBANK, L., Another mode of species-forming. Ann. Rep. Amer. Breeders’
Assoc. § : 4-41. 1909; also, Pop. Sci. Monthly 264-266. Sept. 1909.
472 BOTANICAL GAZETTE [DECEMBER
genes. There is a growing sentiment that all hereditary phenomena must rest
in last analyses upon a chemical basis. DARBISHIRE?+ has made a careful exam-
ination of the starch grains of round and wrinkled peas in pure-bred strains and
in several generations of their hybrids. He finds that there are several uncor-
related features of these starch grains which result in the hybrids having some of
the characteristics of the starch grains of both the parents, thus tending to obscure
the fact that the segregation of the starch characters is perfect.
Miss WHELDALE?S has studied the floral pigments of a large number of
species, devoting her attention most intently to the anthocyan series, but also
including a discussion of xanthein, xanthin, and carotin. A useful summary
is given of the studies of others upon the chemical composition of these com-
pounds, and a large number of observations from her own analyses are presented,
the general result being to show that there is a very large number of different
pigments having a common fundamental structure, which pass under each of
these several names. From these analyses and from experience in cross-breeding:
she concludes that at least two features are necessary to the production of the
anthocyan color: the one a colorless aromatic chromogen of the flavone series,
the other an oxidizing agent which she believes to be a ferment. The details of
Miss WHELDALE’s methods of analysis and the lengthy list of literature will prove
of great value to students who desire to go into these more intimate problems of
genetics. :
A similar work from the animal side has been attempted by RipDLE,”° with
respect to the melanin compounds, though the author presents no work of his
own, simply bringing together in an instructive way the more recent results of
investigations in this field. One unfortunate feature of Rippie’s work is his
unfamiliarity with the Mendelian work from the experimental point of view. He
thinks that he has proved the utter fallacy of the entire body of Mendelian teaching,
and that he has demonstrated the continuity of the so-called unit characters, @
statement which contravenes the experience of all investigators who have studied
the behavior of pigment characters in actual breeding. No epigenetic hypothesis
as yet gives the slightest hope of enabling such predictions as are successfully
made continually by workers with the unit character conception.—GEORGE H.
SHULL
Perception of light.—HAseRLANpT?7 attempts to strengthen his theory of
light perception by plants, especially on the physiological side, acknowledging
HIRE, A. D., On the result of crossing round with wrinkled peas, with
especial reference to their starch grains. Proc. Roy. Soc. London B 80:122-135- 1908.
25 WHELDALE, Miss M., The colors and pigments of flowers, with special reference
to genetics. Proc. Roy. Soc. London B 81:44-60. 1909.
———, On the nature of anthocyanin. Proc. Cambridge Phil. Soc. 15+ 137-18
1g0Q.
26 RIDDLE, O., Our knowledge of melanin color formation and its bearing on the
Mendelian description of heredity. Biol, Bull. 16: 316-351. 1909. s:
27 HABERLANDT, G., Zur Physiologie der Lichtsinnesorgane der Laubblatter.
Jahrb. Wiss. Bot. 46:377-417. 1909. .
1909] CURRENT LITERATURE 473
that the experimental work there leaves much to be desired, while the anatomical
relations have been pretty fully cleared up. He discusses, therefore, the investi-
gations that have attempted to eliminate the lens action of the papillose epidermis
by making plane the surface with water, oil, gelatin, etc.; after which he addresses
himself to the question of the residual lens action of the epidermal cells. He
shows that in all cases with oblique illumination there remains an unequal excen-
tric distribution of the brightness on the inner walls of the epidermal cells, though
of less intensity than with dry epidermis. Inquiring into the sensitiveness of
the cells in distinguishing differences of illumination, it appears that the more
sensitive leaves have about the same capacity, 1/30, as the human eye under
ordinary circumstances, the extremes being 1/75 and 1/12.5. But the differences
of illumination in the case of papillose epidermis, even when wetted, is far above
these figures, and, as HABERLANDT proceeds to show, is often greater even in
leaves that have the epidermal cells plane outside and concave on the inner end.
In the latter case the differences were from 1/15 to 10/1, according to the obliquity
of the light.
After discussing the previous more or less contradictory results of the wetting
method, in which some of the experimental leaves were not in condition to per-
ceive the direction of the light and to respond to it, he describes his new method.
This consists of wetting only a part of a leaf of Tropaeolum with water made
plane with a thin sheet of mica, and leaving the rest dry. A zone between the
wet and dry portions is darkened with a paper screen, and the petiole is also
properly protected. Then the two regions are illuminated obliquely from con-
trary directions. By varying the relative areas of the wet and dry regions, and
the intensity of the illumination, it is easy to determine the relative efficiency
of the epidermis under the two conditions. When the areas are equal and the
wet area receives double the intensity of light, its direction on the dry side con-
trols the response. When the intensities are equal and the wet area is 2.2-4.8
times the dry, the latter still dominates the reaction.
We translate the latest statement of HABERLAND?’s theory: “The perception
of the direction of light results, according to my theory, from the differences
in brightness or the different distribution of intensity upon the inner walls of the
epidermis, which may be brought about in various ways. The smaller differ-
ences of brightnesss may be produced by the mere convexity of the inner walls
of the epidermis. These eased iment as a = (miissen die Reizschwella
erreichen) if the outer wall tion of the light is thus excluded;
and they may suffice even if the normal collection of light by convex outer walls
is made impossible by wetting. Then even the wet leaf perceives the direction
of the light and returns, although slowly and generally incompletely, to the usual
light position. In these cases the epidermal cells act as optical stimulators, and
and though they may be dispensed with to a certain extent, the promptness and
precision of the movement are enhanced by their effect in increasing the intensity
of the stimulus. This action is especially valuable in the last phases of the adjust-
ment, when by the diminution of the angle of incidence, the differences of bright-
474 BOTANICAL GAZETTE [DECEMBER
ness on the inner walls, so far as these differences are due to the convexity of
the inner walls, may become less and less until they fall below the liminal value
as a stimulus.’”—C. R. B.
Symbiosis in orchids.—A recent paper by BERNARD?’ recalls his previous
studies on the germination of certain orchid seeds and on the relation of fungi
to the tuberization of orchids and potatoes. The present paper advances our
knowledge of these fungi and places considerable emphasis upon their place in
the development of the orchid group. Three species (Rhizoctonia repens, R. lanu-
ginosa, and R. mucoroides) have been recognized, described, isolated, and grown
in pure cultures for considerable periods. though no spore-bearing structures
have been observed, they probably belong to the lower basidiomycetes. The
first-named species seems to be the most primitive and most widespread in its
symbiosis.
Two series of orchids were studied, those of epiphytic and those of terrestrial
habit. The growth of th dling plished experimentally in test tubes
upon suitable media, and the effect of the fungi and of various concentrations
of the media upon their development carefully studied. The results are most
interesting and suggestive, and may be summarized as follows: (1) Orchids
exhibit a progressive development of symbiosis corresponding to and probably in
some measure the cause of their development in phylogenetic series. (2) The
evolution in epiphytic and terrestrial families is parallel, and symbiosis is the
only common factor which can account for this parallelism. (3) The evolution
in symbiosis manifests itself in an advance from independent germination of see
with normally developed seedlings, to a germination entirely dependent upon the
infection of the embryo by fungi and the development of seedlings characterized
by protocorms. In the adult plants various progressive stages of symbiosis
are exhibited, from an intermittent infection with sympodial habit to permanent
symbiosis associated with the monopodial habit of the host. (4) The fungi vary
in virulence according to their species, their host, and the length of time ‘they
have lived outside those hosts. Very virulent cultures act upon more highly
developed orchids in a similar manner to more attenuated cultures upon more
primitive species. (5) Concentrated solutions of the culture media have an
effect upon germination similar to that produced by infection by fungi, and both
symbiosis and growth in concentrated media result in increasing the concentra-
tion of the cell contents, which seems to be the necessary condition for the develop-
ment of these specialized plants.—Gro, D. FULLER.
Recent contributions from the Gray Herbarium.?°—A. EasTwooD pat?
Am. Acad. 44:563-591. 1909) has published a ‘Synopsis of the Mexican an
28 BERNARD, Noét, L’évolution dans la symbiose. Les orchidées et leurs cham-
pignous commensaux. Ann. Sci. Nat. Bot. IX. g9:1~196. 1909. ;
20 Contributions from the Gray Herbarium of Harvard University, New Series,
No. XXXVI (Proc. Am. Acad. 44:563-637. 1909); and No. XXXVII (Proc. Bost.
Soc. Nat. Hist. 34: 163-312. pls. 23-30. 1909).
1909] CURRENT LITERATURE 475
Central American species of Castilleja” in which 54 species are recognized, 17
being new to science. A clear and concise key precedes the enumeration and
description of species; the same author (ibid. 603-608) describes 12 new species
of Mexican flowering plants belonging to different genera—B. L. RoBiNson
(bid. 592-596) in a “Revision of the genus Rumfordia”’ records six known
species, of which two are here described for the first time, and (ibid. 613-626)
under the title “Diagnoses and transfers of tropical American phanerogams”
publishes 20 new species and three new varieties, and makes several new combi-
nations.—H. H. Bartiett (ibid. 597-602) gives a ‘‘Synopsis of the American
species of Litsea,’’ recognizing 11 species, 5 of which are new, and (ibid. 609-612)
under ‘‘Notes on Mexican and Central American alders” describes one new
species and three new varieties; the same author (ibid., 627-637) has published
14 new species and varieties of flowering plants chiefly from Mexico, and pro-
poses one new genus (Basistelma) of the Asclepiadaceae.
J. R. Jonnston has recently issued, as Contribution no. 37 of the above series,
a “Flora of the islands of Margarita and Coche, Venezuela,” based chiefly on
his own observations and collections made on the islands during two expeditions,
one in 1901, the otherin 1903. A brief historical sketch of the botany of the islands,
an account of the physical features, a catalogue of the species, a list of the economic
and medicinal plants, the distribution of species, the composition and relationship
of the flora are the main topics presented, to which is added a bibliography of all
works that relate directly to the vegetation of the islands. Approximately 650
species are known from Margarita and Coche at the present time; and the author
estimates that this number represents about three-fourths of the entire flora.
Forty-two species and two new genera have been discovered on Margarita during
the course of Mr. JoHNsTon’s preparation of the present publication. The relation-
ship of the flora, as would be expected, is with the mainland. The work forms
an excellent basis for future investigations on the flora of the islands; it is, more-
over, of particular scientific value since the plants on which the catalogue of
species is based are deposited in several of the larger herbaria of Europe and
America.— . GREENMAN.
Anatomy of Zamia.—Martre*° has recently published an addition to the
number of investigations in the interesting field of cycad anatomy. Zamia is
the subject of the present work, the species studied being Zamia floridana and Z.
integrifolia. The paper shows the anatomy of Zamia to be of the ordinary cycad
In the embryo, the vascular plate of the cotyledonary node is a protostele.
Each cotyledon receives three strands, which undergo the usual branching and
anastomosing, and exhibit transfusion tissue at the tips. At the base of the
cotyledons the strands are mesarch and may be even concentric; they are exarch
in the middle and upper regions. The first leaves are opposite, but later ones
3° Marre, H., Sur la structure de l’embryon et des germinations du genre Zamia
L. Bull. Soc. Sci. et Med. de ’ Quest 18:nos. 2 and 3. 1909.
476 BOTANICAL GAZETTE [DECEMBER
have the spiral arrangement. The leaf traces arise in the cortex, between the
cotyledonary bundles, and there are three for each leaf. Girdling is acquired
early. There is no clearly differentiated root structure in the embryo.
The manner of germinating is the same as that described for other cycads.
The tardily appearing root is tuberized by the activity of a zone of cambium which
appears immediately within the endodermis, and proliferates to such an extent
that the components of the root cylinder are displaced and the cortex is exfoliated.
The root cylinder may be diarch, triarch, or tetrarch, and reduces toward the tip.
In its lower part all the tissues are well differentiated, even the endodermis and
pericycle. The stems of young seedlings have no secondary wood, the cylinder
being composed entirely of endarch leaf traces, which become mesarch farther
out in the leaf. The pith of this siphonostelic stem sometimes contains a few
isolated vessels. Contrary to the usual custom of looking upon these vessels
as remnants of the embryonal protostele, the author prefers to regard them as
vestiges of ancestral structure.
Marre corroborates the discoveries made by Lanp and the reviewer that the
cotyledonary node of Zamia is of the usual cycad type, that there is a tendency
to lobing at the tips of some of the cotyledons, and that there is an irregularly
arranged cortical cambium, though he describes the last as vaguely cambiform,
and does not attribute to it any phylogenetic significance.
The microphotographs are a retrogression from the clear and beautiful draw-
ings of the earlier papers—HeLEn A. DorETY.
Temporary anaerobiosis.—NaBoxIcu has published from time to time in the
past ten years short papers upon the behavior of plants under anaerobic conditions;
now he gives us a monograph on the temporary anaerobiosis of higher plants.>*
There is an elaborate consideration (45 pp.) of the previous work, practically all
of which is decidedly adverse to his views. Then follows the experimental part,
showing how anaerobic growth is recognizable and presenting the results of an
analysis of its physiological characteristics, its periodicity, dependence on temper
ature, réle of sugar and alcohol, energetics, and cell division.
NABOKICH reports two categories of physiological facts which are not clearly
consonant. On the one hand, anaerobic growth seems to be identical with
aerobic as to the grand period, geotropic response, and cell division (including
karyokinesis). On the other hand, there are peculiarities of anaerobic growth,
such as the course of its curve at different periods (though: this can be paralleled
in aerobic growth under proper conditions), its specific dependence upon tempera
ture and sugar solutions, and the invariable death of the cells. Though NABo-
kiIcH holds that his experiments have fully established his fundamental assump-
tion of the capacity of higher plants for anaerobic growth, he confesses that he has
not succeeded in obtaining an amount of growth beyond the limits of possible for-
3 Nasoxicu, A. J., Temporare Anaerobiose héherer Pflanzen. Landw. Jahrb.
38:51-194. pls. I, 2. figs. 2. 1909.
1909] CURRENT LITERATURE 477
tuitous alteration in length by turgor changes; but he thinks this explanation
precluded by the different behavior of the plants with sugar solutions under aerobic
and anaerobic conditions respectively. Because of the great increase in growth
late in the culture period, he also rejects the possibility of anaerobic growth being
due to residual oxygen, even though there must be some not removable by his
methods. Taking everything into consideration, NABOKICH believes that aer-
obic and anaerobic growth have no necessary connection, being called forth by
different factors
A reading eS this paper leaves one unconvinced that the author has estab-
lished his point, in spite of the apparently prodigious labor the prolonged and
very difficult research has involved, with results of minimal consequence. It
seems another case of the mountains in Jabor.—C. R.
Hybridization.—GicL10-Tos? publishes an attempt to reach theoretical]
explanation of the varied phenomena of hybridization. His views are based on
his theory of ‘‘biomolecular addition” which may be briefly stated. He supposes
that a fertilized egg, A, consists of a series of molecules a, 6, c,d, ¢, . . . n
that after a series of chemical transformations owing to assimilation hers arrive
finally at a chemical constitution m,n, 0, p, q, . after which each divides
into 2a, 2b, 2c, 2d, 2e,...., sak ice to ile ceusnad condition. When
this occurs, “‘regeneration of the germ” would be complete. In sexual repro-
duction if 4 nd Bg represent the biomolecules of he two germ cells, the
Organism developed from the fertilized egg, AB, might have the capacity of
regenerating the whole “biomolecule” which formed it, in which case we would
have parthenogenesis; or if complete regeneration is not possible we will have
sexual reproduction, each of the germ cells regenerating a part. The case in
plants, in which both sexes are usually present in the same individual, is not spe-
cifically considered.
rom this point of view the writer interprets sexuality, synapsis and reduction,
fertilization and hybridization. It is further supposed that the zygote AB, while
retaining an equal number of male and female biomolecules, yet in the ontogeny
undergoes certain modifications, so that the resulting germ cells will be ¢M and
N?2; and that the constitution of these is such that they can be added to each
other (“biomolecular addition”) to produce again ¢AB9.
On this basis the results of crossing are considered from an a-priori point
of view and a number of “laws” are enunciated. Explanations of Mendelian
Segregation, blending, and other phenomena of hybridization are offered, and
predictions made as to the results of cross-breeding reciprocal hybrids. The
formal character of the hypothesis makes it probable that it will fail to conform
to many of the facts of hybridism, but its viewpoint is very suggestive. For the
details of its application see the original paper.—R. R. GATEs.
32? GiGLIo-T 08 ERMANNO, L’eredit& e le leggi razionali dell’ ibridismo. Biologica
2:no. Io. pp. 3
478 BOTANICAL GAZETTE [DECEMBER
Graft hybrids.—WINKLER33 has published a further account of his experi-
ments with graft hybrids of Solanum nigrum and S. lycopersicum. In all, thirteen
graft hybrids have appeared, belonging to five different types, which are named
S. tubingense, S. Darwinianum, S. Gaertnerianum, S. proteus, and S. Koelreuteri-
anum. Of these forms the first three resemble most S. nigrum, and the last
two resemble the tomato, S. proteus being very variable in leaf shape and having
leaves similar to S. Darwinianum. S. Gaertnerianum, like many sexual hybrids,
often has sterile anthers. S. Darwinianum and S. Koelreuterianum are very
unlike in their vegetative organs, but similar in their flower characters. S. pro-
teus produces reversions to the tomato, which it most resembles, while S. tubin-
gense reverts to the nightshade, it nearest pare
Some viable seeds are produced by the =r hybrids, but the percentage
of germination is very sma n S. tubingense the length of time required for
ripening the fruit is short, ike that of the nightshade, while the maturing time
for the seeds is intermediate, and hence the ripened fruit contains immature seeds.
The chimeras described in WINKLER’s previous papers also recur, and some
others are of peculiar character; e. g., one chimera was S. lycopersicum on one
side and S. tubingense on the other, and another was composed of the two graft
hybrid forms, S. tubingense and S. proteus. In S. nigro-tubingense one flower
had two white petals and three yellow. S. Darwinianum similarly originated
from a chimera which was partly S. nigrum and partly S. Darwinianum, and a
pure shoot of the latter was obtained only after four decapitations of this branch.
S. Gaertnerianum appeared five times on different grafts, in some cases as an
independent shoot and in others from a chimera.
The forms are all held to be true graft hybrids and not mutations, because
they are intermediate between the parents. W1vKLER thinks that graft hybrids
differ from sexual hybrids in their marked late but it is too early to say
what the cause of this may be.—R. R. Gat
Heredity in the pea.—T wo papers by DarpisHtrE% deal with he edity in the
a. The first is a very interesting analysis of the types of starch grain in round
and wrinkled hybrid peas. It is to be hoped that this valuable paper will lead
to many other studies of a similar sort, because very little attention has been
paid to the ontogenetic development of Mendelian characters. GREGORY** had
previously shown that round and wrinkled peas possess different types of starch
33 WINKLER, Hans, Weitere Mitteilungen iiber Pfropfbastarde. Zeitschr. Bot.
12315345. pl. I. figs. 4. 1
ARBISHIRE, A. D., on the result of crossing round with wrinkled peas, with
especial reference to their starch grains. Proc. Roy. Soc. London B 80:122-135-
jigs. 6. tables 2 1908.
experimental estimation of the theory of ancestral contributions
in havedikys Pre Roy. Soc. London B 81:61-79. tables 8. 1909.
35 GREGORY, R. P., The seed characters of Pisum sativum. New tees 2:226-
228. 1903.
1909] CURRENT LITERATURE 479
grains. In the round pea are large potato-shaped grains (p grains), while the
wrinkled pea has compound grains (c grains), averaging six parts to a grain.
In addition, both types possess a few very small circular grains and in the wrinkl d
pea are found occasional f grains, though these are very rare. In the hybrid F,
the starch grains are perfectly intermediate between those of the parents, although
the character roundness is dominant. The majority of the grains in F, are large
and round; some, however, are compound, averaging three parts to a grain.
Heterozygotes (DR) in the F, were of a similar sort, but extracted wrinkled peas
in F,; showed an occasional p grain. DARBISHIRE concludes that round differ
from wrinkled peas in four pairs of characters: (1) the shape of the pea, (2) its
absorptive capacity for water, (3) the shape of the starch grain, and (4) the con-
stitution of the starch grain, i. e., whether single or compound.
In a more recent paper the anihoe tests the theory of ancestral contributions
as applied to Mendelian heredity. Yellow and green peas obtained from India,
Canada, China, Russia, and other sources gave similar results. The recessive
character appearing in F, was shown to behave as though it was as pure as that
borne by a pure race. It was concluded that “there is nothing like ancestral
contributions within the limits of a single unit character,” and that in such cases
in predicting the results of a cross, ‘‘the somatic characters not only of the parents
and of the ancestors of the individuals mated, but of the individuals themselves,
may be left out of account,” aioe being based on the theory of the contents
of the germ cells.—R. R. GATE
Diversity in cotton.—Several bulletins by Cook and his associates in the
Department of Agriculture*® are not only of great commercial value in directing
the activities of cotton growers, but are also of considerable interest as studies
in variability and its causes, and the results of crossing. Without attempting
to mention all the topics considered, one or two of them may be referred to as of
special interest. The diversity found in Egyptian cotton introduced into Ari-
zona is = to be ts — kinds: (1) diversity due to hybridization, (2)
diversity due t mplet tization, (3) diversity due directly to differences
in the physical esvirenae and (4) diversity i in different parts of the same plant.
Slight differences in the external conditions have large effects in the productivity
of individuals by determining the production of sterile or fertile branches.
36 Cook, O. F. Page agn es of a primitive character in cotton hybrids. Bureau
Pl. Ind., Circ. 18. pp. 11. 190
he s cla is line breeding over narrow breeding. Bureau PI.
Ind., Bull. ae Pp. 45. 1909
pressed and fauinstheed characters in cotton hybrids. Bureau PI.
, Sup
Ind., Bull. 147. pp. 27. 1909.
Coo K, O. F., McLacaian, A., AND Meape, R. M., A study of diversity in
ei cotton. Bureau PI. Ind., Bong 156. pp. 60.. pls. 6. 1909.
Coox. O. F., Local adjustment of cotton varieties. Burean PL. Ind., Bull. 159.
PP-75- 1909.
480 BOTANICAL GAZETTE ._ [DECEMBER
It is found that when a race of cotton is introduced into a new locality it
usually shows at once an epidemic of variation in tats directions, many of the
plants showing a large amount of deterioration. The tendency can be eradicated
only by selecting from the best (unmodified) ee in the new locality.
In this manner a reasonab y constant race is finally obtained in the new locality,
the process being known as local adjustment. New-place diversity is thus a
phenomenon distinct from ordinary fluctuating variability, and of prime impor-
tance in connection with acclimatization. These new-place variations are not
adaptations to the conditions, but are considered to be ‘‘experiments in accommo-
dation” or as “‘affording the materials from which the more definitely accommoda-
tive characters may be developed.”’ Neither are they directly impressed upon the
plants by the external conditions, but much of the diversity is believed to represent
“transmitted characters which have been able to come back into expression because
the change of conditions has disturbed the previous adjustments that selection had
established.”—R. R.
Plants with HCN.—MrranpeE finds’? that green plants which contain
cyanic compounds, if subjected to the action of chloroform, ether, and other vapors
that check photosynthesis, exhale a strong odor of hydrocyanic acid. He proposes
therefore to use GUIGNARD’s test3® in connection with this process to determine
what plants contain such compounds. The test requires only a short time and
avoids all the complicated and troublesome processes necessary for chemical
analysis. Besides it seems to be more delicate and certain. Thus MIRANDE
seit that the presence of hydrocyanic acid may readily be detected in Arum
maculatum, a plant in which the existence of HCN, long in controversy, has lately
been ae by analysis.—C. R. B.
Geotropism and metabolism.—The only experiments which have claimed to
show a direct connection between irritability and metabolism have been those of
CzaprexK and BErTEL, who found that in geotropically stimulated roots there was
an accumulation of reducing substance, which they identified as homogenistic
acid. The precise character of this substance has been controverted. Now come s
Grare and LinsBAvER,?? who report that in the material used by them (Lupinus
albus and Vicia Faba) the absolute amount of reducing substances (character
not determined) is very small and far below the values found by CZAPEK. More-
over, there was no constant difference between the stimulated and the unstimulated
roots.—C. R. B.
MrRanDE, M., Influence exercée par certaines vapeurs sur la cyanogénése végé-
tale. ead rapide pour la recherche des plantes A acide cyanhydrique. Compt.
Rend. Acad. Sci. Paris 149:140-142. Ig09. _
38 Bot. GAZETTE 43:288. 1907.
x0 Grare, V., AND Linsnaver, K., Zur Kenntnis der Stoffwechselnderungen bei
geotropischer Reizung. Sitzb. K. Akad, Wiss. Wien Math.-nat. Kl. 118:907-916.
1909.
GENERAL INDEX
Classifie] entries will be found under Contributors and Reviews.
New names
and names of new genera, species, and varieties are printed in bold face type; syno-
nyms in zalic.
\canthocereus, Britton and Rose on 310
L
£
f
Adaptation in a nea Scott on 315
Adelmeria, Elmer on 396
Revinctia ‘Kusano 0 n development of 75
African plan rage ae on 157, 395; Gilg
paris 1574 Girke on 157; Krause on 158;
ax
Arostyras, "Perkins os ee on 158
gave, Drummond o
Aaacponi, extology 0 of a6
Albinism, Baur on fohenrence of 72
Alchemilla, Steiner on mildew of 235
Algae, fungus p f
rmnaria, Rigo in 33 fie icae 14
anita, markable “epane nce
of grav ity on direction os growt 414
bo yg) oe nets Acacia 5th
Asner ‘Naboki ch on temporary 476
y, Gleichenia, Boodle and Hiley
gymnosperms 84, “Hill and
Rae on Sia ovule yrica, Ker-
shaw on 3 - Banotace Smith on 77
Anisophyll ss a
Anthers, —— of, Schneider on 317;
Steinbrinck 0
Anthocyan.
Anulocaulis Sta
son diepensak of “ate by 319
Apparatus for plant ered 30
Appun aL gre emalen
Arbaumont, J. de, w Ears 239
Aecoceral Chry santa variation of 4,
7
Ascomycetes, perithecium of, Engler and
7
Peedegcorktn Dale on sexuality 398
Aspergillus, Dale on sexuality 39
plenium, M
eo. F. 283, 321
Auxograph, demonstration 302
Awano, S., work of 79
481
B
Baccaureopsis, Engler on 396.
Bachman, Freda M., work of 80
Bacillariaceae, Miiller on 396
Bacillus subtilis, ammonification by 106
Bacteria, Meyer on nucleus of 77
Bailey, Irving
poe ‘Eeology” (see Warming)
Bal - 470°
i K
Barker, P. T. fs yond: 159
Barnes, C. R. 64, 66, 67, 73) 74s 751 79; 78,
79, 80, 154, 155, 157s 160, 2375 — 239,
240, 306, 308, 313, 317, 318, 319, 320,
39%, 399; 400; 472, 4 475, 4
Bartlett, H. H., work of 4
Bateson’s «Mendel’s viicapies of hered-
ity” 61
Baur, Edwin, work of 72, 4
ork
468
Beccari, O., work of 157; - ** Asiatic
Bergen eph Y. 275, 459
Bergeocacts Britton and Rose on
Be what work of 75
rnard, Nol, work of 474
_ W., ork of 232
232
Breeding corn, Morrow and Gardner on
396
iene Ass’n, rae Rept. 392
Briquet, J., — 3
Panon: N. L., work of 310
Brown, W.
Bruchmann, i, “work of 76
Buchanan, R. bas
231
Burbank, L., work of 471
Butters, F. K., work of 240
€
Cabomba, embryology of 57
reve ies ae! on 395
Calesta V.,
Ca gitice. Robinso on and Fer nald on 158
peat compared with Hel acaie:
Calopogon, embryo sac 129; gameto-
phytes a megaspores 126; micro-
pores
Campbe iL, ds ie oe of 316, 317
Caragana, Komarov on 234
—— monoxid, ‘Kraschénnikoff on
of 240
oreopola ae rustica
ae Standley on 158, 234; viscidula
Caalophyilum, Butters on seed of 240
Central Amer vee? — on non Hes
475; Maxon of 3
on Se of pe Seallseribed aa
fro
Centrosomes, in Marchantia, Schaffner
on 80; ypoca’ atin Neha on 73
Cephalocerews Giirke on 396
as s, Purpus on 1 38, 233; Weingart
15
Colne. Murrill on 396
ye ei ache —— on 395
Chamaeanthus 233
Chamberlain c. ie eg 74, 76, 77, 80, 234,
466
Cheninacts of Lycopodium sperms,
Bruchmann on
Chemotropism of fungi, Schmidt on 78
Chloranthaceae, Robinson on 234
Chlorophyceae, Gardner on 232
Chlorophyll bodies, d’Arbaumont on 239
Chlorophyll, in evergreens, Stein on 320;
oe eeds, Monteverde and Lubimenko
n 74
Christ, H., “‘Flore de la Suisse” 154;
work of 23
Christensen, C., work of 157
avior in Oenothera
48
Q
&
‘ou.
Og 5
FeeE Es
°
B
Q
5
§
5
Soe Merrill on 395
Clem ao ork of 396
Bohs of 1
ia ux, A.,
Calletoivickaite, pale ett in, Carica r2,
Lindemuthianum 15
ins,
INDEX TO VOLUME XLVII!
[DECEMBER
Commicarpus, Standley on
Coniothyrium Fuckelii, variation of 11, 19
Connaraceae, Merrill o
Conn’s ‘Agricultural bacteriology,” a3
Contributor s: Atkinson, G
5 4 :
81, 239, 308, 311, 312, bey ee 317)
318, 319, 320, 30 4 Cowles, H. C.
e€
Greenman, J. M 155, 156,
st, a b 395; 465,474 4743 Cries. s, Robert
He
Man Me Land, W I G4 ; Lipman,
‘ 06; Lyon, H. 442; McAllister
aes ?
F. 200; Merwin, H. C. 442; Osterhout,
W. J. V. 98; Ottley, Alice M. 31; Over-
;_ Pace, Lula 126;
ce,
nou chi, Shigéo aS; 236, 231; 380
Convolvu ‘lac cae 233
Conzattia, yee n 310
Cook, Mel. T. 56; work of 479
ooper, ww. S. 154
Copeland, E. B., work of 157, 234, 395
Corn breeding, Morrow and Gardner on
6
Costaricia, Christ on =
Cc Rica, plants of 2
Cotton, Cook on diverse in 479
Coulter, J. M. 81, 239, 308, 311, 31%
34, 315) pre 317, 318, 319, 329 393+
Co ati iL oe 149,152 30% 4 65
Crassulaceae, Britton and Rose on 310
Creonectria, euwer: ‘oh 395
Crocker, Wm. 463
ruciferae, Calestani nm 232
Cryptocarya, gimemeiites on 395
1909]
Culture solutions, Benecke on 78
nd on 395
Cyperaceae, Palla on 23
gy, of Aglaozonia 380; of ae
"380; of Florideae, Kurssanow on 2
D
Dangeard, P. A., work of 159
work of - 472, 478
f
nzlin on
Dode, ork o
Delchedacbee Ule on 233
Dorety, Helen A. 475
Dérfler’s ‘‘Botaniker Adressbuch” 66
Drosera, Meera g Ss on a hybrid 234
Drummond, J. R., work of 396
Dryopte Gicisionsen on 157
Durand, "Filia s J. 66, 77
Durham, F. H., work of 467
E
East, E. M., work of 307 471
474
nt a
Seciinadag minutiflora, Britton and Rose
Ec er Sophia 224
Betrogella apr arge 338
hlam, F., 157, 233
Facog se S, "DeCandolle on Philippine
395
Plcosacidre n japonicum ean
ig abe ecd influence of on microorgan-
S 359; and seiphettan Bae Kolton-
Imer, A. D ee = of 157, 396
Elmeria, Elmer 0 157
Embryo, of Bra sini 57; of Cabomba
57; of Cas stalia oe
96; of Juniperus
of Nymphaea eae 365
‘ tonia ae 2 i
mbryo sa alopogon 129;
double fertilisation, Porsch 0 nS pyr
of Widdring-
INDEX TO VOLUME XLVII!
483
geny of 76; of Habenaria 242; of
Pandanus, Campbell on 316; _ of
Smilacina 200; of Symplocarpus,
familien” 67; work of 7, 157, 395
Englerodoxa, H6 wi 232
Endosperm of H are 248
Entophivets bulligera 33
Environment, Maasegre & ae due to 1
Sp taboos variation in
4 Merrill on 1 oe
work of 73
s, Clements and Shantz on 396
158
ax oO
uxena, Calestani on
hel eg Stein on n chloroph in 320
Evolution, tenden mong gymno-
A. J. 463
pele Lutz on fungus 78
Exogone, Hennings on 234
Fawcett, W., — . 232 396
ernald, ole
Copeland on 157, 234; Mexican 310;
oe on Bolivian 158, on Ecua-
= a,
Fennentaton and respiration, Kosty-
tschew on 399
Fertilization, _ — 383; in Juni-
Tus 31; rsch on phylogeny of
76
ars of Darwinism” 392
pe
ouble
«pity ye
phyllie” 306
"
Figdor’s “ Aniso
Fin
Flora of ‘Krakatau, Campbell on 317
Florideae, Kurssanow on cytology of 236
Fossil plants, Scott on adaptation of 315;
Sin on araucarian 4
Fraine, “E. se work of 314
Frost, ake
due to environment I; ¢
on 78; North American, Peck on 396
G
ametogenesis in Cutleria 3
ome eng of Pe nea 126; of
484
gymnosperms 92; of Juniperus 31; of
61
Bot ne eins I
ioe
gor
re cinia, ‘Miers on 158
Gardne
Gates, R. > 72, 179, 477, 478, 479
— work 4 in 478, 47
Geotrop and metabolism, Grafe
a nes on 480; perception ee
Newcombe
Gepp, A., soci of 396
Te aS. oe see
m. iquet
Gueninatae: in Cu tleria 383; in seeds
of Xanthium under oxygen pressure
8
3°97
Gibsonia , Masse
Giglio- Tos, ne ar of a
ilg, E., of 157
Gleichenia, Boodle and Hiley on anatomy
of 3
Goebel’s “Experimentelle Morphologie”
152
Gonolobus leianthus 296; macranthus
a9
Grafe, V., work of 480
Graft hybrids, Pe ae? on 478
Grasses, gs on Cuban 309;
ilger apr 158
Geaviy, infue ence on weedica of growth
a 414
ee Herharice: contributions from 474
G eer ’s “Manual, »» emendations by Robin-
son and Fernald 1 58
e, E. L., work of 2
Gre 396
Gresanuis q. M. 146, ae ee 309, 311,
cology” (see Warming)
Guatemalan plant 233; Eichlam on 157;
undescribed 2
Girke, M. ppstehes of 157,3
Gymn osperms, evolution: tendencies
practi we Hill and Fraine on seedling
314
Gritanenon fae Kern on 395
H
Habenaria, a c of 242; mega-
spores of 244; sie dees of 248
serrata G, work of 472
Hall, J. G
Harrissella, Foweeit and Rendle on 3096
ler, E., work of 2
Hays’s. “A little Maryland garden” 309
eald, F. D., work of 395
Heating of leaves, Molisch on 318
INDEX TO VOLUME XLVII}
[DECEMBER
Hefferan, Mary 6
Heliocereus, Britton and Rose on 310
Hennings, P., work of 2
Heredity, albinism, Baur on 72;
Darbishire on 47 28
in pea,
Herter, W., work of 1 157
ae ee veered on 310
, T. G., work of 3
Hitchooc k, A. - wok ‘of 309
Holstia, Pax 158
pees nn’s ee wendeniete Vorle-
ungen uber mechanische Probleme
en
des Botanik”’ 66
a J sie work of 158, 395
rold, ork of 2
Housed? S nes. Zoocciis” 308
House, H. D., work of 233, 234
Howe, M a tse of 1
Hurst, C. C., work of 471
Hybrids, chromosomes of Oecenothera
179; Giglio-Tos on 477; Rosenberg
n Drosera 234; Winkler on graft 47
Hydrocyanic acid, Mirande on plants
480
Hylocereus, Britton and Rose on 310
Hypocreales, Seaver on 395
I
no, S., work of 159
Impatiens Gilg on 157; Hooker on 158,
se Otere of albinism, Baur on 72
Ipomoea, House on 234
Japan, onsedh of 234
Jehlia, Rose on 310
Jensen’s ““Haupilinien des _natiirlichen
ee oe
Johns n, J. R., work of 475
Jor cena ‘General bacterviogy” ee
Julianiaceae, ovule of, Ker shaw
Juni td gametophytes and ple ate
in
Justicia ee 300; Tuerckheimi-
ana 3
Karsten and Schenck’s “ Vegetations-
bilder
Kary: okines in Oedogonium, Van Wis-
sash Gn ase
Keeble e. wack of 69
Kennedy, P. B., work of 2 32
ern, F. D., work of 395
Kershaw, Edith M., work of 319, 320
Koch’s '« Pharmakognostischer Atlas
466
Komarov, V. L., work of Pas
Kostytschew, S., work
Krakatau, Campbell on ton of 317
1909]
Kranzlin, F., work of 158, 395
Kraschénniko ff, T., work of 240
usano, S., work of 75
— ium, americanum 3 “che 336; ene-
; rabenhorstii
Larix, structure of wo
48
Lathyrus, Wooton aid aoe on 234
Leaves, Awano on wetting of 79; form
tion of starch in 224; of gym nosperms
86; light and-concavity of 459;
lisch on heating of 318; Smith on tem-
perature of isolate
Ledermanniella, eee on hg
poe sae, Hassler
Lemaireocereus, stead n pee Rise on 310
Laeacbls: W. W., work of 313
Leptocereus, Bri and Rose on 310
Light, and concavity - leaves 4593
Haberlandt on perception of 472;
t
Schiirhoff on perception gu 93 and
protein synthesis, Zaleski on 400; and
Paagioees n, Léwschin on 80; and varia-
tion o ungi 5
Ligusticella, Coulter and Rose on 310
395
Ss
hte
&
ise)
ia)
i)
a 2 ee
—
ee
aq
Ling , Engler on 396
# tied K., work of 319, 480
as. B. 106
Lipm
L fea. gaara on x 5
Loc work of 471
Locomotion : low temperature, Teodo-
Potent. ‘Britt on and Rose on 310
Loranth Merrill on 395
Léwschin, _ work of 80
, work of
@
oO
n 233; Herter on
of 1 385 sperms,
c
Lycopods,
new “thee waletd genus 31
Lyon, Howard 44
M
Macbridella 39
MacDougal’s
North American deserts” 307
Mackensen’s ‘Trees and eee of San
Macrogiuae conan on 157
Macrosporium Brassicae 15
Maige, Mme. G., work of 238
5
ee Botanical | features of
INDEX TO VOLUME XLVIIf
485
Makino, T., work of 234
Malvaceae, Hassler on 233
Malme, G. O., work of 232
Marae, Eichlam on £57, 233
aple sap, pressure in py
n development of
fc)
Mea ae R. 9
Mechanical tissue in stems, influence of
traction on formation of 251
Megaspores, <= Calopogon 126; of
Habenaria
Merrill, ae Ds suede of 158, 395
Merwin, re
trobus “wa n on a new genus of
esoniecad oe opods 3
Metabolism ap geotropim, Grafe and
Linsbauer
Mexico, fortis of, furan on 310; plants
of 158, 159, 232, er 234, Rose on 309;
Williamsonias a
Meyer, A., wor a
Microorganisms, faders of electricity
on
Microspores of pend Pears 130
Milbraedia, Engler on 306
Milk, influence of eeiciy on bacteria
in 363
Mirande, M., work of re
a in Synchytrium
Mobius’ s “Bo ‘ner? mas mabtroskoplaches
Prak iekon
Moffatt’ S "ighe fungi of Chicago
region” 31T
Molisch, H., ‘Das Warmbad” 155};
work of 31
rset morphology of 159
onostroma, — on 157
preci s N., work of 74
gaye oiaee Ruppia,
a
criticism of
i E. work of 396
,_Lepeschkin on mechanism
Musc re R., “work of 234
Mycorhiza, Peklo on 237
N
Nabokich, A. J., work of 476
Nakai’s “Blora Koreana” 1
N es, es, Saliebery o n extrafloral 79
Nectrieae, Seaver 0 158
486
ie Rago tote of 56
Neodreg
Necnirs. ‘eee
Pax on 158
eourbania, eect ind Rendle on 232
Newcombe, ¥. C., work of 76
Nilsson Ehle, He, "work of 470
North American flora 156
Nucleus of bacteria, gate! on 77
Nucleoli in Marsilia
Rycoeeeie Britto n and Risse on 310
Nymphaeaceae, phere of 56
O
Oedogonium, Van Wisselingh on 237
Oenothera, copier or of chromosomes 179
Olive, E. W., of 159
Coasters of Satie Tahara on 400
Orchidaceae, Cogniaux o aoa can 157;
Bat Pa ‘ae Rendle on 232, 396; Finet
olfe on 158; Bernard on
in 474
sha sen of 146
Orias, Dode on 232
Ortherodendron, Makin 234
bose Coulter ae Rowe on 310
Osmotic press an permeability,
réndl a
Osterhout, V
O si B. 159, 398
Ovule, gymnosperms go; — pares
aceae, Kershaw on 320; ca,
aw on anatomy og nae ee
Widdein ia 161
gtoni
Oxygen pressure and the germination of
Xanthium seeds 387
Pace, Lula 126
Pachycereus, Britton and Rose on 310
Palicourea leucantha 295; mexicana 295
Palladin, W., wank of 79
Palla 5 ot work o
. nimeflacene, Tschourina on 232
Pampanini, R., work of 2
32
andanus, Campbell on oe sac of 316
otton 400
—/
! wie wet Laesare of 1 58
Parathes crocalyx 295
arish, S. B. 62
Pax, E. , work of 158, 23
ea, Da rbishire on heredity in 478
*échoutre’ s “Biologie florale” 393
eck, C. H., work of 396
G.J.
eirce,
Peklo, J., k of 237
Pelozia, Rose on 310
3 enaeaceae, Stephenson morphology of 315
Ste
’eniocereus, Britton and Rose on 310
INDEX TO VOLUME XLVII
[DECEMBER
Pe ereskiopsis, Eichlam on 157
Perithecium of Ascomycetes, Engler and
Prantl on 6
Perkins, J., work of 158
Permeability Tréndle on osmotic pres-
18
Phanerosorus Copeland on 157
Philippine plants, Robinson on, 23
opeland « ON 234, 305; peed on ei
sha re Merrill on 158
Phillips, F. F. J. 2
Phiyctochyttam shials 338; planicorne
Shei ithe and electricity, Koltonski
on 160
ee eine = roots, Linsbauer and
Vouk o
Phy Hlanthiinn Chinese on 234
Phyllosticta, variation in 13,
15
| y, of gymnosperms 82; of Juni-
Passive, apparatus for plant 301
f 158
e of wood of 47; edulis,
study of 2 an
Be ati catenatum 294; sophoro-
arpum
Plankica: e Sececes on 233
Pleurococcaceae, ye Se ke on 232
work of 8
Porsch, Otto, work of 76 Peas:
Potassium d sodium, similarity in
behavior of 98, 106
Prantl, K., work of 67
Pro ochromogens, eae ae = 79
Proembryo, of Jun
Protein and light oie bee "Tales
a — hispidulum 299; ate
paz
Prcnddbasterdin, Hassler on 233
, Ga i ron 232
zia, Rose o
as structure of rood of 48
m”
urpus, J. A., work of ee 233
R
Panaley ¢. “Wild flowers and trees of
154
a, Britto ose Rose on 310
Ranunc et Briquet 0 23
Reed, Geo
Reimarochloa, “Hitchcock on 309
endle, A. B., work of 232, 39
Papen Maige on 238; and soe
mentation, Kostytschew on 399; 4n
light, Léwschin on 80
1909]
Reviews: Bateson’s ‘‘ Mendel’s eet
A peer 61; Beccari’s “Asia
ms” 155;
“9 Bas- et ake Moyen-Congo” 311
Bacterial!" ”
ioe De orflers Botan Ein Sy
Hays s
it Maryland garden’ 300;
Holtermann’s “Schwendener’s Vorle-
ea tenon she Ider” och’s
“ Pharmako pesoshachis © 466;
MacDou ugal’s “Botanical features of
North har ican deserts” 307; M
kensen’s “Trees and shru ha of Sais
poionm ” 355; Modbius’s staat 8
mikroskopisches _Praktik 466
Moffa tt’s “Higher fungi of, Ghicase
region” 311; Molisch’s “‘Das Warm-
bad” 1535; Nakai’s “Flora Koreana”’
h holzkunde” 312;
Schrenk and Spaulding’s ‘Diseases
deci forest en? 6;
Seward’s “‘ Darwin and modern science”
308; Stahl’s “Biologie des Chlo
phylls” 64; Strasburger’s “‘Zeitpu
der Bestimmung des Geschlechts” 63
omson’s “Heredity” 62; Troup’
“Indian woods nd their uses” 31k;
Van Rosenbu: rgh’s “Malayan ferns”
= = pokes ming’s ‘‘Oecology of plants”
495
Rhipealis Novyaesii, Giirke on 157
Rhizidium bulligerum 3383 Sphaero-
carpum 326
Rhizophidium ampullaceum 338; bre-
Mes S322, 325; minutum 323; sphaero-
326
Riddle, O ©; ais of 472
7
Robinson, B. L., work of 1 ae 475
Robinson, C. B., work o.
Roez] and the type of Washingtonia 462
INDEX TO VOLUME XLVII
487
Rolfe, R. A., work of 158
Roots, Linsbauer and Vouk on photo-
tropism of 319
rk of 239
Rosenstock, E., work - : fe 396
Rubiaceae, ause 0
Ruellia humifusa aol: memes
298; pygmae
Ranta rdia, Robineo on 475
Ruppia maritima, a eriticlans 228
Russell, H. L. 2
S
Saccardo’s ‘“Chronologia della flora
Italiana” 394
Salisbury, E. J., work of 79
Salix, Dode on z
Salts, effects on ammonification by
Bacillus subtilis 106
S AG ork of
Sapotaceae , Smith on nig my o
of 77
Sap pressure, in birch 442; in maple 446
Sargassum, idee of Tahara on 400
sey a aus
Ww, out of I
Schneider s “Handbuch "ag Laubholz-
oe” 3r2
Sch hneider, J. M., work of 317
Ss cacak and Spaulding’s. “Diseases of
deciduous Pgh trees” 156
work of 2
Schroeder, B 3
Schiirhoff, P., 79
Scion and stock, Griffon. n 320
citamineae Be aes n Philippine eee
jation of 9
5
395
Seedlings modifiability of transpiration
Seed, sof Ca lophyllum, Britton on 240;
ing on chlorophy ll of 745 longevity
eg cn iss on.
Selinicereus, Britton & nd eee
Senecio, How ellii lithophilus ss i
schler 234
ries ria, va anion in 3, 12; Lycopersici 27
Setchellanthus, Brandegee o
x in dioecious plants, Darling on 74
Sexuality of Keven and Ascophanus,
n 39
poe *Baewik and modern science”
—o oe 3 = of 396
Shul ck
Shull Gar A. 3053 8 397: 466, 467
Sinnott, Edmund 8; work of 400
Ss. rt rom ont 138
Small, J. M., work of 396
488
Smilacina, embryo sac of 200
Smit h, John cio gr oe
Sm ith, 15. HL;
Smith, Winifred, geek SOF 77
and potassium,
behavior of 98, 106
Solanum Rovirosan 297
Sohations, Benecke xe os 78
similarity in
233
pe ali, ae of 5
on chemotaxis of
yycopodiu eT
meager eared fy Seaver on 395
eR ge Steiner on 235
Spillman, W. J., work of 46
Spore igieteiaeuts of fungi, variability
in 20
co We pir ae Se neal 64
Stam . eri s 89
Stan dley 5 AG Ges of 138, on 309
Starch, te leaves, ee ion of 2
Stein, Cacilie, w
Steinbrin jee wor
er mechanical — + 2
na oi i. E. L., work of 315
Steven ee
Stock pa scion, Griffon on 320
Stone, G.
East bur. urger’s s “Zeitpunkt der Bestim-
des Ge peng! 63
Sivan: Stella G.
Strobilus of soeteriee deer 86
typocaulon, Escoyez on centrosomes in
3
Sutton, A. W., of 470
Septees in Paci end on 474;
algal- -animal, Keeble on 69
Symplocarpus, Ro piaiclall on 239
Ry siplocns. Brand on 395
Synchytrium, mitosis in 339
Sukatscheff, W., work of 234
Tahara, M., work of 4
Excess Se 15h 232, 30, 395, 474
Temperature, of isolated leaves, Smith
on 73; ees on locomotion at
low sn
eodoresco, E. C., work om 240
he eetopar. Pohl on
aoe Horold on American 232
homs n’s ‘Her acd
6 8
geB
Hu
c
‘S
n and Rose on 309
3 ectroidea, Seaver Nn 395
thoni ampanini
W. L.
cae orae in a septate 50
ction, influence on 8g formation of
pase actor a in stems 251
on eg
SO acts’ SNE | = ya De
3
as
7 = poe | Gee fies. Breen. Sree, | » |
rhs
ot
INDEX TO VOLUME XLVII!
[DECEMBER 1909
Transpiration,
modifiability in you "8
seedlings 275;
; Sampson and Allen o
3
Trichostelma, ciliata 296; oblongifolium
29
Trifolium, Kennedy on 232
Trondle, a work of
ows $ “Tadian woods and their uses”
Tschouring, O., work of 2
mboa, Pearson on Se a ek of 312
U
Udotea, A. and E. S. Gepp on 396
e, E., work of 233
Umbelliferae, Boissieu on 395; Coulter
and Rose on 310
Vv
Sora th (see Warming)
urgh’s ‘Malayan ferns”
Venezuela, aga ton on ripe 5
Viola on 233
otuietis ae variation of 4, I1, 29
Vo rk of 319
beer
465
uk, V., wo
W
Warming’s “ Oecology of epee! 149, 465
re yom an _ wg type of 462
Watso 3 f 318
Webeucnens. Brian. ot Rose on 310
Widdringtonia, ovule, gametophyte, and
mbry es
Wei ingar wy. ork of 158
ein ba S Brittod and Rose on 310
Whildale, rant work of 472
Wieland, G 2
Wilcoxia, Briton ae Rose on 310
lle, N., work of 2
Williamsonias of the Tisteca alta 427
Wi sige , H., work of 72, ie
hc.
Wittrockiela, Wille
Wood in Pinus, stricta e of 47
Wooton, E. O., kor 158, 234
Wright, ee 13 i work of 395
x
Xanthium seeds, oxygen pressure and
lads oo is oO f 3 7
Xyris, Malme on 232
x
pee ee Shigéo 75, 236, 237, 380
t, influence of electricity on 372
Wisse ingh, va work of 2
233
Z
Zaleski, W., work of 400
Zamia, atte on anatomy of 475
Zoosporogenesis in Aglaozonia 384