THE GREAT GROUPS OF BRYOPHYTES 
315 
organized into a central stem-like axis bearing two rows 
of small, often crowded leaves. In consequence of this 
the Jungermannia forms 
are usually called " leafy 
liverworts," to distin- 
guish them from the 
other Liverworts, which 
are " thallose." They are 
also often called "scale 
mosses," on account of 
their moss-like appear- 
ance and their small 
scale-like leaves. 
205. Anthoceros forms. 
This line contains com- 
paratively few forms, but 
they are of great interest, 
as they are supposed to 
represent forms which 
have given rise to the 
Mosses, and possibly to 
the Pteridophytes also. 
The thallus is very Sim- FIG. 289. Anthoceros gradlis: A, several 
pie, being differentiated gametophytes, on which sporogonia have 
neither in structure nor 
form, as in the two other 
lines ; but the special de- 
velopment has been in 
connection with the spo- 
rogonium (Figs. 282, 289). This complex sporogonium 
(sporophyte) has a large bulbous foot imbedded in the 
simple thallus, while above there arises a long pod-like 
capsule. 
The chief direction of the development of the three liv- 
erwort lines may be summed up briefly as follows : The 
Marchantia line has differentiated the structure of the 
developed ; B, an enlarged sporogonium, 
showing its elongated character and de- 
hiscence by two valves leaving exposed 
the slender columella on the surface of 
which are the spores ; C, D, E, F, ela- 
ters of various forms ; G, spores. After 
SCHIFFNER. 
