BRYOPHYTA. 187 
The archegones of the common Liverwort are clustered 
upon special branches, a few centimetres in height. These 
branches expand into lobed discs at the top, and beneath 
these the archegones appear. They grow out as trichomes, 
and finally consist of a rounded cell (germ-cell) enclosed 
in a flask-shaped vessel (Fig, 103). 
390. Fertilization takes place in wet weather by the 
antherozoids swimming to and down the open neck of the 
archegone. As a consequence, the germ-cell begins divid- 
ing, and finally develops into a spore-fruit containing many 
spores, intermixed with spiral threads called elaters. The 
use of the latter appears to be to aid in the dispersion of 
the spores (Fig. 103, X). 
391. In most cases the spore-fruits split open to permit 
the escape of the spores, which soon germinate and pro- 
duce a thalloid mass; this develops directly into a new 
plant in the lower forms, and in the higher soon begins the 
development of a stem and leaves. 
892. There are four or five orders of Liverworts, includ- 
ing (1) the Crystalworts (Order Ricci- 
aces), which are terrestrial or aquatic 
thalloid plants; (2) the Horned Liver- 
worts (Order Anthocerotez), which are 
terrestrial thalloid plants with slender 
spore-fruits (Fig. 104); (3) the Liver- 
worts proper (Order Marchantiacee), 
i . a 5 Fie. 104.—A Horned 
terrestrial thalloid plants, including the Liverwort (Anthoceros 
Common: Liverwort (Marchantia poly- apocrine, iE split. 
morpha) and the Great Liverwort (Co- ag 
nocephalus conicus), both large, flat, branching plants grow- 
ing in moist places about springs, brooks, ditches, etc.; (4) 
the Scale-mosses (Order Jungermanniacex, Fig. 101, ZZ), 
