14 
longer or shorter periods of unfavourable 
conditions. 
In suitable soil the spore germinates, growing 
out into a filmy, heart-shaped plate scarcely 
one-third of an inch 
across. This is 
known as the fro- 
thallus or prothallium 
(Fig. 2). It very 
much resembles a 
liverwort, but can be 
distinguished from it 
by its paler green 
colour. It lies pros- 
trate on the soil to 
Fig. 2.—A prothallium which it is attached 
aizaanind Riss; by a number of 
Archegonium. root-like processes, 
yhuzotds (Rh.) which are given off from the 
under-surface. Amongst the rhizoids one can 
distinguish numerous small projections. These: 
are the male sexual organs, the autheridta 
(Fig. 2 Anth. and Fig. 3). Each antheridium 
contains several male sexual cells—the sperms 
(sp.). Near the notch of the heart-shaped 
prothallus may be seen the female sexual. 
organs—the archegonta (Fig. 2 Arch. and Fig. 4). 
fad ee 2 
