280 FOUNDATIONS OF BOTANY 
Do both occur on the same thallus? On what part of the thallus 
do they occur, and do they differ in this respect ? 
340. Antheridia.— The antheridia are formed as outgrowths 
from the upper surface of the crenate receptacle, but by further 
growth of the receptacle they become imbedded. They should be 
examined under a high power and sketched in outline. The anther- 
idium produces numerous motile antherozoids, each with two cilia. 
341. Archegonia and Sporophytes. — The receptacle with recurved 
rays bears the archegonia. Note whether they occur above or below 
and in what relation to the rays. How are the archegonia protected ? 
Note the cells which surround 
the central canal and form the 
i) nium. Does the archegonium 
open upward or downward? At 
the base look for the germ-cell. 
The antherozoids enter the 
central canal and penetrating 
to the egg-cell fertilize it, after 
which it begins to divide and 
grows into a sporophyte. In the 
older specimens, therefore, the 
sporophytes will be found more 
or less developed. The archegonium remains upon the tip of the 
sporophytes. The mature sporophyte contains the spores and also 
peculiar elongated tapering threads with spiral thickenings. These 
are called elaters. 
Fig. 205. — Sectional View of Female 
Receptacle of Marchantia. (* 5.) 
342. Hepatice.— Marchantia represents only a small 
division of the Hepatice, and is not typical of the larger 
number of species. In spite of this it is chosen for study, 
because it is widely distributed and more available for 
study than most others. In most species the fruit lasts 
but a little while and good material is hard to obtain. In 
Marchantia the fruiting organs are abundant, more gradual 
in their development, and more persistent. Marchantia and 
elongated neck of the archego- 
