described already in its greater minuteness.
The archegonia of Marchantia are produced
on the under surface of a somewhat umbrella-
shaped, deeply lobed, stalked receptacle. This
body corresponds in the mode in which it
takes its origin from the notch in the anterior
margin of the frond, with the ordinary vege-
tative shoot, of which it is obviously a modifi-
cation. Its development has been well de-
scribed by M. Mirbel.* The structure of the
archegonium, and the commencement of the
development of the fruit, correspond very
closely with what has been described in Pellia.
The mode of formation of the spores and
elaters differs, however, considerably. The
latter, which in thelast-named plant, are nothing
more than fusiform septate cells, attain in
Marchantia, as well as in many Jungermanniae,
a more complicated structure. Their develop-
ment has been described in an admirable con-
tribution by Mr. Henfrey, who finds that the
young elaters are, like those of Pellia, elon-
gated fusiform tubes, and contain at first only
colourless protoplasma.-j- Soon after starch
granules are deposited in their interior, and
they are converted by a growth which is much
more rapid in length than in breadth, into
very slender, hollow filaments, attenuated at
each closed extremity. Still later, the starch
and protoplasma disappear, and at length
faint streaks, denoting the nascent fibres, are to
be perceived upon the walls. These become
gradually more and more distinct, till, in the
mature elaters, they present themselves as
strong flattened bands. In Marchantia there
are two fibres, which coil in opposite direc-
tions, and are confluent by their ends at the
extremities of the tubes in which they are
contained. At the time of the scattering of
the spores the cell-membrane gives way, and
the elastic fibre rapidly uncoils, at the same
time lengthening considerably. The parent
cells of the spores in Marchantia are also, at
an early period, fusiform. They are arranged
side by side with the young elaters, from
which they differ in being very much broader.
Each of these cells is converted, by the forma-
tion of transverse septa, into a series of four,
which afterwards separate from each other.
In each of the new cells, the protoplasma in-
creases in quantity and assumes a yellow
colour. Still later it begins to accumulate
into four distinct masses, each of which be-
comes invested in a cellulose membrane, and,
after the solution of the membrane of the
parent cell, assumes the structure and appear-
ance of the ripe spore.

72. Mosses. The Mosses are distinguished
from the leafy Hepaticae, first, by differences in
the structure and arrangement of the stem and
leaves, involving greater complexity ; secondly,
by the fact that the leafy axis is not developed
directly from the spore, but, with the inter-
vention of a confervoid structure (proto-



* Recherches Anat. et Phys. sur le Marchantia,
Mem. de 1'Acad. v. xiii. p. 380.

t Transactions of Linnoean Society, vol. xxi.
p. 106.



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



238

nema),* resembling in all its relations to the
future plant, the mycelium of the Fungi and
Lichens.

73. First period. Germination of the spore. ^
The spore of the Mosses is a nucleated cell,
the solid contents of which are granular, and
consist of protein compounds, starch and dex-
trine. From the budding out of its membrane,
results a hollow filament, which, as it lengthens,
divides by a succession of transverse septa.
It then begins to branch in all directions,
each branch resembling the parent, and rami-
fying in the same manner. Hence results an
entangled network of filaments of a brilliant
green colour, which spreads over the moist
surface on which the spores have been sown.
At length some of the filaments are observed
to give off lateral branches which differ from
those previously formed in being more slender
and containing less chlorophylle. In some of
these the terminal cell, after dividing four or five
times, becomes globular, and is transformed
into the rudiment of a leafy axis.

74. Development of the antheridia and arche-
gonia. These organs are usually found in
groups, which are situated either at the termi-
nation of the stem or branches, or in the axils of
the leaves. In either case they are surrounded
(with the exception, in many genera, of the
axillary antheridia) by special arrangements of
modified leaves (involucres). Those involucres
which surround the antheridia are called
perigonia, and are composed of leaves much
smaller than the ordinary leaves of the stem.
Those leaves which enclose the archegonia,
small at first, attain a large size as the fruit
approaches maturity. In some (hermaphro-
dite) mosses, both antheridia and archegonia
are contained in one involucre.

75. In the very diminutive plants belonging
to the genus Phascum, which we select as ex-
amples on account of their great simplicity of
structure, the groups of archegonia are termi-
nal, those of antheridia usually axillary. The
growing extremity of the stem (terminal bud)
or axillary bud, when destined to bear repro-
ductive organs, instead of developing to a new
axis, becomes flattened in such a manner as
to present a slightly convex disc, which takes
the place of its conical growing extremity. It
is upon the surface of this disc that the rudi-
ments, whether of antheridia or of archegonia,
originate, by a process precisely similar to that
which we have described in the commencing
development of the antheridia of Anthoceros.
The rudiment consists, as in Anthoceros,
of four columns of cells, combined so as to
form a cylindrical club-shaped body. The
development and ultimate form of the arche-
goriium corresponds so completely with what
has been described in the Jungermanniae, that

* From the very recent observations of Gronland
(Mem. sur la Germination des Spores de quelques
Hepatiques, Ann. des Sc. Nat. 3 m * S. xx.), it appears
that among the higher Hepaticae with cut leaves,
the first result of germination is always a branched
and septate filamentous protonema, resembling that,
of the Mosses in its relation to the leafy stem.

f Hofmeister, loc. cit. pp. 6571.; Bruch &
Schimper, Bryologia Europaea, Fasc. i. p. 5.



it is unnecessary to describe it. The fully
formed antheridium of Phascum is a club-

Fig. 165.




Section of termination of fruitful stem of Phascum
cuspidatum,oQ diam.

On the right a female, on the left a male inflo-
rescence. From the slightly convex surface
which forms the summit of the stem, spring in
the one case the archegonia, in the other the
antheridia, along with numerous jointed fila-
ments.

shaped body of about the same length as the
archegonium, and consists of a central mass of
minute quadrangular cells, which is enclosed
by a single layer of tabular cells, in contact
with each other by their edges. Shortly be-
fore the antheridium arrives at maturity, the
quadrangular cells, each of which contains a
spiral filament enclosed in a lentil-shaped
vesicle, are dislocated. This is followed by
the total disappearance of their membranes, so
that the vesicles float free in the cavity of the
now ripe antheridium. No sooner is this the
case than the organ gives way at its summit,
and discharges its contents in the form of an
intestine-like coil of mucus, consisting of the
lenticular vesicles with their contents. Soon
after, this is dissolved, and the spiral filaments
commence their active motions.

76. Development of the fruit. The early
stages correspond with those described in Pel-
lia. At a period when the lower dilated portion
of the archegonium is about fivetimes its ori-
ginal length, the young fruit, which is a fusiform
cellular body, does not occupy more than its
upper half. In the meantime the cells form-
ing the tissue subjacent to, or in the immediate
neighbourhood of, the base of the fructified
archegonium, have multiplied with such acti-
vity, that the end of the stem has again assumed
the form of a cone, on the summit of which
the fruit is borne, while the aborted archegonia
are scattered round its sides. In its further
development, the fruit grows much more
rapidlv in length than in breadth, and in con-
sequence of its extension upwards being op-
posed by the resistant structure of the canal
of the archegonium, its lower end presses
downwards in such a manner as to cause the
absorption, not only of the cellular tissue of
the archegonium, which is subjacent to it, but
of that of the conical summit of the stem. In



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



this manner it becomes firmly implanted, the
tissue which surrounds it assuming the form
of a sheath, and receiving the name of vagi-
nula. During this process, the dilated portion
of the archegonium has increased in size, and
has now attained about ten times its original
length. Finally, it gives way at its line of
junction with the vaginula, and is carried up-
wards on the summit of the still lengthening
fruit.

77. Development of the spores. The upper
portion of the cylindrical fruit, which is des-
tined to become the capsule, begins, some
time after the calyptra has given way, to dilate
rapidly. Soon after there is formed, by the
separation of the external and superficial lay-

Fig. 166.




Section of half -ripe fruit of the same, 50 diam.
The globular dilatation exhibits the following
parts : a, the capsule. Within this, and
separating it from the central portion, is a dark
space, which corresponds to a cavity of the
form of a hollow cylinder ; b, columella ; c, super-
ficial layer of central portion ; d, remains of
archegonium ; e, vaginula. (From fig. 164 to 166
from Hofmeister.)



239

diately after its division into two halves. On
the surface of each half cellulose is secreted,
so that the spherical cells which are thus
formed possess a delicate cellulose external,
and a very distinct inner membrane (primor-
dial vesicle.) This last divides into four por-
tions (the young spores), each of which
becomes invested with a layer of cellulose.
The ripe spore has been already described.
The capsule now gives way at the line of its
insertion on the pedicle which supports it.
It is by the opening thus produced that the
spores make their escape after the dislocation
of the layers of cells immediately surrounding
them. Phascum differs from all other genera
in the absence of all trace of an operculum.

78. Ferns. No two plants could be found
which differ more completely from each other
in the appearance which they present to the
ordinary observer, than a Hepatica and a Fern,
at the moment that the spores of each arrive
at maturity ; yet, in the history of their organ-
isation and development a very close corre-
spondence exists. The immediate result of
the germination of the spore of a Fern is a
frond similar to that of the simpler forms of
Hepatica ; on this frond antheridia and arche-
gonia are formed. In each fructified arche-
gonium, a central germ-cell is developed to a
new individual, widely different in organisation
from the parent. It, in its turn, produces
spores, the germination of each of which is the
commencement of a new circle of phenomena
similar to the one which precedes it. Dividing
this circle into two periods, as before, we have
the following stages in the development.

79. First period.* Germination of the spore.
The mature fern-spore consists of a delicate
transparent vesicle, which is invested in a
brown resistant external membrane. Germi-
nation consists in the budding out of the trans-
parent vesicle so as to form a nipple-shaped
projection, which penetrates the external mem-
brane. The projecting part divides repeatedly
by transverse septa. About the same time a
second budding out takes place in the oppo-
site direction, which is destined to the forma-
tion of a root. By the further growth of new
cells, a flattened two-lobed organ is formed
the Prothallium.



Fig. 167.



ers of cells from the central portion, a cavity
of the form of a hollow cylinder, the axis of
which coincides with that of the fruit. At
this stage, the central portion consists of an
axile column of large cells, closely invested by
a single layer of smaller ones (the columella) ;
a superficial layer of cells, about four times as
large as those last mentioned ; and lastly,
between the two, a layer of nucleated cells,
with granular contents, the primary parent
cells of the spores. The development of these
last consists in the disappearance of the nu-
cleus of each, and the substitution for it of
two others; this being accompanied or fol-
lowed by the division of the primordial mem-
brane into two new vesicles, each of which

encloses a nucleus. A cellulose membrane is Early condition of prothallium of Gymnogramma
now tormed at the surface of contact of the chrysophytta, about 20 diam. (Heafrey.)

two vesicles by which the original cavity is
bisected. In the cavity of each of the result-
ing nucleated cells, two new ones make their




appearance, apparently by contraction of the
primordial membrane, either before or imme-



80. TJie antheridia. The antheridia are situ-
ate on the under surface of the prothallium,



* Hofmeister, I c. pp. 78 82.



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



240

and take their origin as follows. A hemisphe-
rical projecting portion of one of the superfi-
cial cells is cut off from the rest by a horizon-
tal septum as in Anthoceros. This is divided
by a single transverse septum. In the result-
ing terminal cell a second septum is formed,
inclined to the horizon at a small angle, which
is followed by a third, inclined in the opposite
direction. Both of the cells resulting from
these divisions, and subjacent to the last-formed
septa, are again divided by perpendicular septa
coinciding with the axis of the papilliform
rudiment. In one of the resulting cells there
is then formed a perpendicular septum, which
meets its predecessor at an angle of 45.
Hence results a club-shaped body, consisting
of a four-sided central cell, filled with granular
mucus, and enclosed by six others, having the
following arrangement. Four of the form of
segments of a hollow cylinder, which are in
contact by their edges, surround the central
cell on all sides. It is surmounted by a fifth,
which is hemispherical (the terminal cell last
formed). A sixth, the cell resulting from the
first division by a horizontal septum, is cylin-
drical, and serves as a pedicle on which the
whole is supported. The central cell is con-
verted by a successive division into a round
group of dice-shaped cellules, in the interior
of each of which a delicate lenticular vesicle
is formed, which contains, rolled up in its in-
terior, a spiral filament. The ripe antheridium
bursts at its summit, and the escape of its
contents is, as in the preceding cases, followed
by the bursting of the vesicles, and the com-
mencement of the active motions of the spiral

Fig. 168.




Aniheridia of Pteris aquilina, 260 diam.

On the right is seen an antheridium from which
cells containing antherozoids are escaping; in
the centre another, which has not yet burst ; on
the left a third, which has already discharged its
contents. (Thuret).



filaments (antherozoids.) In each filament
the extremity which is directed forwards du-
ring motion, is broader than any other part,
while the opposite extremity (posterior) tapers
off into a long filament. The anterior coil of
the spiral bears on the surface furthest from its
axis a number of delicate cilia. The motion of



the antherozoid is of two kinds of progression
and of revolution round the axis of the spiral.

81. The archegonia. At a period somewhat
later than that at which the rudiments of the
antheridia begin to appear, there commences
on the inferior aspect of the prothallium, and in
the immediate neighbourhood of the notch by
which its anterior margin is bisected so as to
form two lobes, an active development of new
cells. The result of this is the formation of
a cushion-like projection of the surface bor-
dering the notch above mentioned, upon the
anterior aspect of which the archegonia are
formed.

82. Each archegonium takes its origin from
a cell, which is distinguished from those sur-
rounding it by the comparative abundance of
granular mucus which it contains, and by the
presence of a distinct central vesicular nucleus.
This cell divides by a horizontal septum into
a superior and an inferior portion. It is from
the latter, which is hemispherical, that the
papilla which forms the rudiment of the pro-
jecting portion of the organs is formed. It
consists, as in theHepaticae and Mosses, of four
contiguous columns of cells, each of which is
a half segment of a cylinder, the whole being
surmounted by a hemispherical terminal cell.
In the further development, varieties are often
observed, even on the same prothallium.
This is dependent on the mode in which
the canal occupying the axis of the mature
archegonium is produced. Most frequently
a central column of cells is formed in exactly
the same manner as an Anthoceros. The cells
forming it are afterwards absorbed and dis-
appear, leaving a four-sided canal. In the
other case, the canal results simply from the
separation of the four piles of cells along their
common line of contact. This is the arrange-

Fig. 169.




Archegonivm of Aaplenium septentrionale, 250 diam.

a, germ-cell enclosed in its parent-cell; the mem-
brane of the latter is still perfect, and separates
its cavity from b, the axial canal. (Hofmeister.)

ment which occurs constantly among the
Equisetaceae, Lycopodiaceae, and Rhizocar-
peas. In reference to the mode of origin of
the germ-cell, there is some difference of opi-
nion. According to Hofmeister,* the cell
which contains it originates by the formation
of a tangental septum in the lowest of the
cells, constituting one of the four columns of

* Loc. cit. p. 80.



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



which the rudiment is composed. According
to Mr. Henfrey *, on the other hand, the germ-
cell is contained in the superior, and conse-
quently deeper, of the two portions into which
the primary nucleated parent cell of the organ
divides by a horizontal septum ; and is dis-
tinguishable before the formation of the pa-
pilia-like structure has commenced. This
account of the matter is not only supported
by analogy, but, as it appears to us, in a very
marked manner by Hofmeister's own drawings.

83. The embryo. Immediately after the en-
trance of the spiral filaments into the cavity of
the archegonium, the cells which immediately
surround it multiply rapidly, in consequence
of which the cushion-like projection of the in-
ferior surface of the prothallium increases in
size. At the same time the germ-cell is trans-
formed into an irregularly egg-shaped body,
which consists of minute cellules, and may be
considered as the primary axis of the future
fern. It originates in the same manner as the
rudiment of the fruit of the Mosses and
Hepaticac, and elongates by repeated divisions
of a terminal cell by septa, inclined alter-
nately in opposite directions. It consequently
presents but one growing point, which is di-
rected, not towards the orifice of the archego-
nium, but, on the contrary, towards the centre
of the cushion-like mass, by the cells of
which it is surrounded. Soon after, however,
there appears on the side of the egg-shaped
embryo, which is directed towards the notch
in the anterior margin of the prothallium, a
second growing projection of its surface. This
projection, at first conical, becomes, as it
enlarges, compressed from above downwards.
No sooner is this the case, than it bursts through
the superficial cellular layer of the prothallium,
at a point which is invariably a little anterior
to the base of the archegonium between it
and the angle of the notch. It now assumes
the form of a symmetrical leaf-like organ, and
begins to project beyond the notch of the
prothallium. The further development con-
sists in the appearance in the axil of this
primordial leaf, of a new axis, the permanent
stem of the young plant. From this axis all
the succeeding leaves take their origin, each
diverging from its immediate predecessor at
an angle of 60.

84. Sporangia and spores. At a point of
the surface of the frond, which always cor-
responds to the termination of a vascular
bundle, a lacuna is formed under the epider-
mal layer, by the separation of that structure
from the subjacent tissue. The floor of this
cavity consists of a pavement of tessellar
cells, some of which grow out into nipple-
shaped projections. In each of these, the
projecting portion is separated from the rest
by a horizontal septum, which is soon fol-
lowed by several others superior and parallel
to it. The last-formed terminal cell now en-
larges, and assumes a globular form, and is
converted by a process similar to that to be

* On the Development of Ferns from their Spores'
Trans, of Linnsean Society, vol. xxL p. 135.
Supp.



241

described below in the rudimentary sporan-
gium of Equisetum, into a central mass of
nucleated cells, with grumous contents (parent
cells), enclosed in a capsule formed of a single
layer of others, which are tabular. In each
parent cell, the central nucleus afterwards
disappears, and is replaced by four others.
This is followed by the division of the pri-
mordial sac into four portions, around each
of which a cellulose membrane is formed.
This membrane becomes the epispore; a second
(endospore), which is distinguished by its
greater delicacy, being subsequently formed
within it.*

85. EquisetacecE. The history of the deve-
lopment of the Equisetaceae corresponds in
most respects with that of the Ferns.

86. First period.^ Germination of the spore.
The spore of Equisetum consists, in its ripe
condition, of a delicate, colourless internal
vesicle, which is surrounded by a more or less
resistant granular membrane, and contains a
central nucleus, and a yellowish grumous fluid,
in which swim oil and chlorophylle granules.
The first change observed in germination con-
sists in the division of the nucleus into two,
and the subsequent formation of a septum
between the two corresponding halves of the
spore-cell. Of these halves, the larger con-
tains nearly all the chlorophylle, and is de-
veloped to the stem; the smaller,the con tents of
which are almost colourless, is the commence-
ment of the root. The prothallium, which
results from repeated cell-division of the larger
half, is an irregularly riband- shaped expan-
sion, growing and branching repeatedly at the
extremity furthest from its point of origin,
and consisting of large, delicate-walled cells,
containing much chlorophylle. One of the
branches is usually observed to be larger than
the rest, and it is upon it that the reproductive
organs are formed.

87. Antheridium.The rudimentary antheri-
dium of Equisetum consists, like that of pre-
ceding families, of a papilla, composed of four
conjoined vertical piles of cells, each pair
slightly overlapping the pair preceding it. In
each of the cells constituting this rudiment a
tangential wall is formed, dividing it into an
inner three-sided, and an outer tabular cell.
The inner cells, which form a central oval
mass, are soon observed to be filled with finely
granular mucus : the tabular cells, on the con-
trary, contain chlorophylle, and form the wall
of the future antheridium. The further de-
velopment of the central mass corresponds
entirely with what has been described in other
families. The antherozoa are larger in Equi-
setum than in any other known example.
They originate by the deposition of a gela-
tinous linear thickening, in the form of an
imperfect ring, parallel to the plane surfaces of
the discoid vesicles in which they are enclosed.
When fully formed, they resemble, in almost

* Schacht, Entwick. des Sporangiums einiger
Farrnkraeuter Bot. Zeitung, 1849. p. 537.

f Hofmeister, /. c. pp. 97103. ; Milde, Entwieke-
lungsgeschichte der Equiseten, &c. Bonn, 1852.



REPRODUCTION, VEGETABLE (VEGETABLE OVUM).



242

every respect, those of the Ferns. The anthe-
ridia of the Equisetaceae are placed, not upon




Antheridia of Equisetum, 300 diam.
c, ripe antheridium, from which the antherozoids
are beginning to escape ; b, unripe autheridium.
(Hofmeister.)

the inferior surface, but along each margin of
the principal branch of the prothallium.-

88. Archegonium. The archegonia were
first discovered and figured by Milde* in