LIVERWORTS.—MOSSES.—CLUB-MOSSES. 9 
cells which are termed parenchymatous, elongated thick-walled 
cells, called prosenchymatous or wood-cells (see page 39); and 
also, in most cases, except in the in- 
termediate orders of Liverworts and 
Mosses, variously formed tubular organs 
which are known under the name of 
vessels. 
From the Thallophytes, by various 
intermediate stages, through an order 
of plants called Liverworts, we arrive 
at another order—the Mosses. In the 
lower forms of the Liverworts, e.g. Mar- 
chantia (fig. 7}, we have a green flat 
thallus-like stem bearing upon its under- 
surface scale-like appendages, the first 
representatives of true leaves. In the 
higher forms, as Jungermaniia (fig. 8), 
the stems and leaves are both more 
highly developed. In the Mosses, e.g. 
Polytrichum (figs. 9 and 10), the stems 
often contain elongated cells, which are 
to a certain extent thickened, and differ 
little from the true wood-cells met with 
in the more highly developed plants ; 
this tissue, too, is often prolonged into 
the leaf, when it forms a midrib. Cor- 
related with this greater development 
of the organs of nutrition we find the 
reproductive apparatus similarly ad- 
vanced in complexity of structure. The 
female element, or oosphere, consists of 
a mass of protoplasm, called the germ 
or embryonic cell, situated in the interior 
of a flask-shaped cellular organ, the 
archegonium, and this is fertilised 
by small spirally-wound filaments 
or antherozoids, which are developed in 
cells, termed sperm-cells (fig. 11, c), 
formed inside a cellular sac-like struc- 
ture called the antheridiwm (fig. 11, a). 
The result of this fertilisation is what is 
commonly termed the fructification (jig. 
9), which will be hereafter described. 
The Liverworts and Mosses are, 
however, destitute of true roots and 
vessels, such as exist in the next and 
all the higher groups of plants. 
eee le be 
aces 
“ 
Fig. 11. Antheridium, a,of the 
Hair-moss (Polytrichum), 
containing a number of 
cells, c, in each of which 
there isa single antherozoid. 
p. Paraphyses, surrounding 
the antheridium,— Fig. 12. 
The common Club - moss 
(Lycopodium clavatum). 
Fig. 13. Fructification of 
the Great Water Horse- 
tail (Equisetum maximum), 
forming a cone-like mass at 
the end of the stem. 
Still ascending, we find in the Club-mosses (fig. 12), Sela- 
ginellas, Pepperworts, Horsetails (jig. 13), and Ferns (jig. 14), 
