at its apex so as to form a single tubular stalk,
just as in the lower Algae.

25. The antheridium of Chara is an orange-
red, and globular body, which is attached to the
stem immediately below the germ-producing
organ. It consists of eight concave, rectan-
gular valves, joined at their edges so as to
form a hollow sphere. At each suture there
is a partition, which is directed to the centre
of the sphere ; while from the centre of each
valve there springs a cylindrical cell, the axis
of which is perpendicular to its inner surface,
so that each cell approaches the centre of the
sphere by its extremity. The whole anthe-
ridium is supported by a ninth cylindrical cell,
which is inserted by its base into the stem of
the plant, and passing up between the corners
of the four inferior valves, approaches the
other eight cylindrical cells at the centre.
From the extremities of the nine cells, there
emanate a number of flexible tubes, which are

Fig. 140.




a, flexible tubes from antheridium of Chara. From
most of the segments the antherozoids have
escaped ; two are in the act of escaping : b, fully
formed antherozoids. 400 diam. (Thuret.)

divided by transverse partitions into a number
of segments. In each segment or cavity an
antherozoid is contained. Each antherozoid
is a spirally coiled fibre endowed with a power
of active motion, which is displayed as soon
as it is removed from its cell. The motion is
of two kinds of progression, and of revolution
round the axis. According to Thuret, two
cilia emanate from each antherozoid, a little
behind its anterior extremity, and it is to
these organs that the motion is to be attri-
buted.*

26. Summary. If we take into consideration
only those families of the Algae in which the
phenomena of reproduction have been more or
less completely investigated, we shall find that
all the instances of the occurrence of bodies to

* For further information see K. Miiller, Die
Entwick. der Characeen, Bot. Zeit. 1845, p. 393.
Kaulfuss, Die Keimung der Characeen. Leipzig,
1825. Varley, On the Structure of Chara in the
Microscropic Journal. Thuret, Ann. des Sc. Nat.
xvi. p. 18.



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



which the term " germ" may be applied in the
sense of the definition given at the outset, may
be included in one of two classes. The first
comprises zoospores and zoosporoid bodies ;
the second, all those forms of germ which re-
quire for their development a previous combi-
nation of two parts or organs, complementary
to each other as regards their reproductive
functions.

27. Zoospores. Of zoospores we recognise
two kinds, simple and aggregate. The simple
zoospore is a pear-shaped or ovoidalbody: it
is composed of transparent, colourless homo-
geneous plasma, throughout the whole of
which, with the exception of the smaller end
(rostrum), granules of colouring matter are
scattered. It possesses no investing mem-
brane, but is provided with a pair of cilia, the
directions and positions of which differ accord-
ing to the class. Every zoospore possesses
a single granule of a red or reddish-brown
colour, which is always placed in the immediate
neighbourhood of the colourless rostrum. Its
characteristic motion is a constant progression
in the direction of its axis, around which the
whole zoospore at the same time revolves, the
transparent rostrum being always directed
forwards. As regards the chemical composition
of the zoospore, the transparent and colourless
plasma is a nitrogenous compound, coloured
brown by iodine. The cilia, as far as their
reactions can be ascertained, resemble the
plasma from which they emanate. As to the
constitution of the coloured granules which
are scattered throughout the plasma, we have
as yet no direct observations ; but from the
form which they exhibit being that which is
always assumed by starch, not only among
the Algae, but also in the green Infusoria, there
can be little doubt that they are composed of
that principle, in mechanical combination with
colouring matter and a fat.

28. In passing from the condition of motion
to that of repose, or, in other words, in germi-
nating, the zoospore is not subject to any sus-
pension of its vegetative activity. From the
moment that it is set free from the parent
plant to that at which it begins to develope
from itself a new plant similar to the parent,
it continues to grow uninterruptedly.

29. Of the aggregate zoospore, the best-
marked example is that which has been fully
described in Vaucheria. In comparing the
termination of a fructiferous filament of Vau-
cheria, with the sporangium of Saprolegnia,
we can at once satisfy ourselves that these are
corresponding structures ; the distinctive dif-
ference being, that in the one the whole pro-
toplasma contained in the termination of the
tube is collected together to form a single large
zoospore, while, in the other, it is subdivided so
as to form a multitude of small ones. In other
words, the single zoospore of Vaucheria takes
the place of the collection of zoospores con-
tained in one sporangium of Saprolegnia. This
fact is all that we mean to imply by the use of
the term aggregate.

30. Zoosporoid bodies. Among these we in-
clude the antherozoids of Cutleria, of the Fu-



223

caceae, of the Florideae, and of the Characeae.
Of the relations of the first two to the true zo-
ospore in form and development, we have al-
ready said enough in theprecedingpages. Those
of the antherozoid of Charaare not so close;
and the structure of the organs in which they
are developed, differs so essentially from any
structure met with in any other family, that it is
inexpedient to found any notions of their nature
or formal relations upon such slender analogies
as may exist. In the case of the Florideae, the
correspondence between the antherozoids and
the zoospores of other Algae, is still less trace-
able ; but the peculiar arrangement of the
bodies in question their being always deve-
loped in different individuals, though in similar
positions as regards the organs of vegetation -
leads us irresistibly to the conclusion that
they have a mutual relation, or are in some
degree complementary to each other in function;
and as we know the production of germs to be
the function of the one, it is reasonable to
assign their fecundation to the other.

GermSy whose development is dependent on
the combination of two organs the reproductive
functions of which are complementary each to
each. Of these it is the leading characteristic
that they do not necessarily pass at once, as
soon as they are set free from the parent, into
active development. If the necessary condi-
tions of temperature and moisture are absent,
they are capable of remaining in a state of re-
pose, without losing their power of germina-
ting. This state may last for weeks, or even
for months. Their second characteristic is
connected with the first ; viz. that they are
always provided with a distinct investing mem-
brane, on the strength of which their power of
resistance to external agents may in part de-
pend. This is well seen in the spores of the
Desmideae and Zygnemaceae.

31. There remain a few examples of germ-
like bodies of uncertain signification, which are
included in neither of the above divisions.
Such are the various forms which occur among
the Florideae, the stationary spores of Sapro-
legnia, and others, of which, as they are still
imperfectly known, sufficient has been said in
the preceding pages.

32. FUNGI AND LICHENS. While, on the one
hand, the Fungi and Lichens present an endless
variety in the organs which constitute their
reproductive system (receptacle), their vege-
tative system (mycelium, stroma, flocci, hypo-
thallus, #c.), on the other, preserves a remark-
able degree of uniformity. It always consists
of a network of cylindrical hollow* filaments,
usually divided at irregular intervals, but some-
times simple. In the latter case the whole
network, however complicated it may appear
at first sight, is in fact only a ramified cell.
This structure, which, in its simplest form is
the immediate result of the germination of the
spore, is the most permanent portion of the
plant, inasmuch as, although every part of it,
considered separately, is transitory, the vege-
tation of the whole is continuous, and its
duration unlimited. It is from it that the
organs which constitute the reproductive sys-



224



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



tern take their origin, and, as its presence is
essential to the existence of the plant, it may
be considered to represent, functionally, the
stem of other vegetables.

33. On the formation and development of
the germ in the Fungi, comparatively very few
researches have yet been made which are not
so deficient either in completeness or accuracy
as to be useless. This being the case, the best
mode of treating the subject seems to be to
select those isolated facts and observations
which are most to be depended upon, and
arrange them in such a manner as to serve as
a foundation for a general view of the subject.
The most simply organised Fungi known, are
undoubtedly those which belong to the genus
Torula. The well-known yeast-plant consists
of a single ovoid cell, whose membrane is per-
fectly simple, and encloses a slightly granular,
transparent fluid. It multiplies by the budding
out of its membrane at one extremity into a
projecting nipple, which soon becomes sepa-
rated from the original cell by a constriction.
As the newly formed germ enlarges, the con-
striction becomes more complete, and at last
separation takes place. After the Torulae,
which are the only examples we are acquainted
with of one-celled Fungi, come the innumerable
Hyphomycetes or thread Fungi,so called because
their reproductive, bears so small a proportion
to their vegetative system, that it is in many
cases altogether overlooked. The growing
terminations of the mycelium filaments them-
selves become individualised, so as to form
the germs, which separate from their parent
cells by constriction, as above described in
Torula. It is this acrogenous mode of spore
formation which Schleiden considers as the
character which distinguishes the true Fungi
from the Lichens*; the latter developing "many
spores simultaneously in the interior of a
larger parent cell or ascus." Among the higher
Hyphomycetes, however, the reproductive sys-
tem appears in a more distinct and developed
form. Thus, in Penicillium it consists of fila-
ments which spring perpendicularly from the
stroma, and are formed of elongated, club-
shaped cells, joined end to end. These stalk-
like filaments branch trichotomously in the
most beautiful manner. From their extremi-
ties there spring others, which are much more
slender, and consist of moniliform series of
minute ovoid segments, separated from each
other by constrictions, which are indistinct at
the base of the filament, but become more and
more complete towards its termination. At
this point the segments detach themselves,
and form the germs of the plant.-)- In other
genera, the perpendicular sporiferous filaments
are woven together into more complicated
structures, the varieties of which it does not
come within our present purpose to describe.
As respects their component elements and the



* Schleiden places all the ascophorous Fungi
among the Lichens. V\ r e shall find, as we proceed,
that such an arrangement is altogether inadmissible.
(Schleiden, Principles of Scientific Botany, p. 157.)

t Corda, Icones Fungorum, torn. i. p. 21.



mode in which the spores are produced, they
do not differ from those noticed above.

Fig. 14-1.




Branching sporiferous filaments of Penicillium verti-
cillatum, about 150 diam. (Corda.)

34. The basidiosporous Fungi are character-
ised by the presence of a distinct membrane
(hymenium), on the surface of which the
spores are developed by a mode which,
though it is still acrogenous, is considerably
more complicated. The hymenium always
consists of elongated pouch -like cells, ar-
ranged side by side, with their long axes
perpendicular to its surface, and in close
contact with each other. Some of these
cells are longer than their neighbours, and
from their free rounded ends, there emanate
processes (usually four in number) in the form
of pedicles. Upon the extremities of these
are borne oval cellules, which, though in their

Fig. 142.




A. basidium with its four basidospores, along with tu-o
other sterile basidia (Geaster rufescens),'3QQ diam.

earliest condition they do not exceed their
pedicles in width, rapidly enlarge, and finally
separate by a kind of constriction. In some
basidiosporous Fungi, as in the Agarics, the
hymenium is external, and its surface exposed
to the atmosphere ; while in others, as in the
Gasteromycetes, it is internal, the spores
being thrown, when detached from their pedi-
cles, into one or more cavities enclosed in the
substance of the receptacle. Of the last-
mentioned division, we select a well-known
genus (Geaster), for the purpose of illustration.



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



35. At the period of the formation of the
spores, the receptacle of Geaster (fimbriatus)
is a solid body of a depressed spheroidal form.
It presents for examination a central mass and
a peridium, the tissue of the latter being con-
tinuous with that of the former only at the
base. The central mass or kernel is originally

Fig. H3.




Diagram of receptacle of Geaster fimbriatus.

The kernel, a, is surrounded by its reticular mem-
brane, which is indicated by the inner of the two
double lines. The outer double line corresponds
to the resistant external layer of the peridium.
The intervening space, 6, is occupied by a delicate
tissue of spherical cells. At c, all these struc-
tures are continuous, as well with each other as
with the mycelium from which the whole ori-
ginates.

solid, but when fully developed, presents
numerous irregular cavities, which are scat-
tered through its substance. It is entirely
composed, when in the solid condition, of
delicate filaments similar to those of mycelium,
the arrangement of which is as follows : The
superficial filaments are closely woven toge-
ther, so as to form a delicate reticular mem-
brane, which invests the whole kernel, and
from the inner aspect of which a second and
very numerous, set of filaments passes off
towards the centre. It is of these, or of their
ramifications, that the corky, semi-elastic sub-
stance of the kernel is entirely formed. If we
examine the cavities which have been men-
tioned as existing in the fully developed con-
dition, we find that they are furnished with a




Section of a portion of the young receptacle of Geaster

rufescens, about 100 diam.

The section has passed through one of the cavi-
ties, and shows the arrangement of the basidia
which form its lining membrane. Some of these
bear spores on their summits.

more or less continuous lining of basidia, bear-
ing spores on their summits. These basidia
have been shown, by careful observation, to
Swpp.



225

be in fact the swollen terminations of the
centripetal branching filaments above men-
tioned. The peridium it is less necessary to
describe, as it has no immediate connection
with the spore-bearing organs. It consists of
an internal and an external layer, the latter
being smooth and very resistant, while the
former consists of delicate, transitory, spheri-
cal cells. In the ripe condition of the Geaster,
the peridium becomes detached, at the same
time splitting from apex to base in a remark-
able and characteristic manner. Geaster may
be considered as the type of a well-known
family, including the Ly coper dons, Bovistce,
and others, all of which are characterised
by the presence of a solid receptacle, furnished
with numerous spore-bearing lacunae. In al-
most all of these Fungi, the arrangement of
the spores with their pedicles in relation to
the basidia are the same, four pedicles ema-
nating from each basidium. In the ripe con-
dition the spores are always of a dark-brown
colour, frequently approaching to black, and
their surfaces are beautifully reticulated with
linear furrows, between which there are little
conical projections. Each spore possesses an
external reticulated, and an internal homo-
geneous membrane. This last encloses a
cavity, which is occupied by a fluid, which
contains numerous oleaginous granules. The
ripe spores, after their detachment from the
basidia, lie loose in the lacunas of the recep-
tacle from which they are set free by the dis-
integration of the basidia, as well as of the
filament with which they are connected.
In this manner, in Geaster, the kernel is con-
verted into a bag, formed of the delicate reti-
cular membrane, described above as its proper
investment. This bag contains a dark-brown
diffluent mass, composed of the remains of
the basidia and filaments along with ripe
spores. Finally, the membrane gives way, and
the spores are disseminated in the shape of a
light, dry-looking powder.

36. We next pass to the consideration of
the Fungi, among which the spore, instead of
being produced at the summit of a basidium,
or at the extremity of a simple filament, is
formed in the interior of a vesicle or pouch,
which is called a theca or ascus. Of these,
the first which we shall mention belong to a
group of subterranean plants, of which the
truffle is the best-known example. The recep-
tacle of the truffle consists of a fleshy mass,
throughout which numerous sinuous cavities
are interspersed. Each cavity is partly lined,
partly filled with the thecae and the cells upon
which they are supported. This receptacle,
like that of all other Fungi with which we are
acquainted, originates from a pre-existing
mycelium. In its unripe condition it displays
on section a number of sinuous empty cavities,
which either communicate with each other,
or open at one or more points of the external
surface. As the truffle advances towards
maturity, the cavities are obliterated by the
formation of a whitish tissue ; so that on sec-
tion, we observe the whole to consist of two
substances the one translucent, of firm con-

Q



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



226

sistence and of a dark-brown colour ; the other
white and opaque. The former, which cor-

Fig. 145.




Sectfon o/par< o/ fAe receptacle of a Truffle, about
250



a, outer layer of the peridium consisting of a
resistant tissue of thick- walled cells ; b, inner layer
of the same, formed of filamentous tissue continu-
ous with that of v, one of the venae internae, or par-
titions by which the compartments (originally
cavities) of the truffle are bounded. Portions of
two of these compartments are seen with the thecae
and septate filaments which they contain.

responds to the partitions which, in the young
state of the truffle, separated the cavities, is
continuous with the external tissue which
composes the envelope or peridium, and con-
stitutes the vena interne of Vittadini.* The
laminae which it forms, consist of filaments
running, for the most part, parallel to each
other. The white substance which occupies
the original cavities of the tuber, is formed
of closed tubes, which are given off in great
numbers from the surfaces of the laminae.
These tubes, which are the terminations of
the filaments of which the laminae are com-
posed, are of two kinds. Some are of equal
diameter throughout, and divided at intervals
by septa ; others, much shorter, are dilated at
their extremities, and contain spores (thecae).
Each theca is an obovate vesicle, and con*
tains two, three, or more spores, never more
than eight. Each spore is invested with a beau-
tifully reticulate, or sometimes warty epispore,
within which may be distinguished a smooth
inner membrane, immediately enclosing the
oleaginous contents.*}*

* Vittadini, Monog. Tuberacearum, p. 2. et seq.
f L. R. & C. Tulasne, Histoire des Champignons
hypogees, 41-50.



37. The ascophorous Fungi are represented
in their simplest form by the Uredineae, a
family which has been studied by numerous
observers on account of the destructive pro-
perties of the plants belonging to it. The
mass which is formed by the growth of the
reproductive organs of Uredo under the epi-
dermis of the leaves of the plants upon which
it grows parasitically, may be aptly compared
to a pustule, a grumous-looking substance,
occupying, as it were, the place of the pus.
On more minute examination of the cavity,
we find that it is bounded by a kind of irre-
gular wall or lining of pyriform cells, the
smaller ends of which rest upon a reticular
cushion of mycelium. These are probably the
enlarged extremities of the mycelium filaments,
with which many of them can be distinctly
traced to be connected. Towards the base of
the cavity other cells are developed, resem-
bling those first mentioned in their general
form, as well as in their relation to the myce-
lium. In these, however, the membrane is
produced inferiorly, so as to form a tubular
pedicle ; while in the club-shaped upper ex-
tremity it is lined by a considerable deposit of
granular protoplasma, so that here the central
cavity is very much smaller than that of the
external membrane. It is in this cavity that
the spore is formed, at first not exceeding it
in size, but afterwards increasing at the ex-
pense of the protoplasma, so as almost to fill
the theca. In other genera, as in Phragmidium,
there are pedicled cells of a similar form, and
originating in a similar manner, which, how-
ever, instead of one spore, develop a number
in their interior ; these spores are arranged in
linear series, and are formed in the same
manner. The protoplasma, however, never
disappears completely, but remains as a more
or less consistent membrane, glueing the ripe
spore to the spore-case which encloses it.
Some of the Uredineae possess a cyst which re-
minds us of the perithecium of the Sphoeriaceae,
to which they are evidently closely related.
The cyst is formed (QEcidium) of a single
layer of roundish cells.*

38. From the Uredineas we pass by a natural
transition to the Discomycetes and Pyreno-
mycetes. These plants have been investi-
gated with much success by MM. Tulasne,
who have shown that they possess the
closest relationship not only to the Lichens,
but to the most simple thread Fungi. The
very remarkable facts which these observers
have discovered, render the study of these
plants more satisfactory and instructive than
that of any other family of the class. The
Pyrenomycetes are represented by Sphoeria,
the receptacle of which consists," as is well
known, of a spherical cyst, which is open
above. Its wall is frequently prolonged up-
wards into a tubular beak, which projects
beyond the surface of the bark or wood in
which the whole plant is embedded. The
membrane of the cyst (perithecium) is usually



* }j. R. Tulasne, Recherches sur les Uredine'es,
&c. Ann. des Sc. Nat. 3me. S. t. vii. p. 12.



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



composed of polygonal, tabular cells ; it is
lined by an inner layer, formed of the com-
mencements of the paraphyses and thecae, and
of the filaments with which they are con-
nected. The thecae are obovate cells, the

Fig. 146.




Theca and paraphyses of Sphoeria, about 300 diam.

membrane of which is of extreme delicacy.
When fully formed, they contain from three to
eight oval spores, the epispores of which are
in the early condition delicate and pellucid,
but by degrees become brown and opaque.

Fi%. 147.




Ripe spores of Cenangium Frangulae, 350 diam.

The contents of the spores, as is observed
throughout the higher Fungi, consist of a fluid
loaded with oily granules. The thecae are
arranged with their long axes perpendicular
to the inner surface of the perithecium from
which they spring, and are intermixed with a
greater or less number of slender, cylindrical
paraphyses. The whole perithecium is usually
enveloped in the filamentous stroma or my-
celium, from which it takes its origin. The
Discomycetes are represented by thePezizae;
between these and the Sphceriae there are dif-
ferences of external form, which, though they
strike the superficial observer as important,
are in reality trivial. While the receptacle of
the Sphoeria is a cyst with an apicial aperture,
that of the Peziza is a cup-shaped disc, the
concave surface of which looks upwards. This
surface is lined with an ascophorous mem-
brane, which resembles in every respect that
of a Sphoeria.