290 



Introduction to Botany. 



mosses perform the same functions as do those of higher 

 plants. 



177. Reproduction of Mosses. — An examination of the 

 apices of moss shoots reveals the fact that archegonia and 



antheridia (Fig. 151) are pro- 

 duced there, in some species 

 both on the same plant, and 

 in others on different plants. 

 The archegonia and anther- 

 idia are small and obscure, 

 W\ /" — N ''3,'«'-^"*V' ^"^d would be overlooked by 

 PwK ilf^aL ''"^t^^i'-t^' the casual observer. The wall 



of the antheridium breaks 

 open at its apex (Fig. 151,^), 



'M rl'' ifP® ^^^ ^'^^ sperms {s and t) 



llM Ww m&^m being freed, swim about in 



the dew or rain which has 

 collected over the plants ; and 

 being attracted by some chem- 

 ical substance secreted within 

 the archegonia (Fig. 151, A) 

 they enter these through their 

 hollow apical elongations, and 

 one sperm in each case fuses 

 with the egg. 



The fertilized egg immedi- 

 ately germinates without leav- 

 ing its position in the archegonium, and the rod-shaped 

 embryo, as it elongates, breaks off the narrow upper part 

 of the archegonium and carries it as a sort of cap called the 

 calyptra (Fig. 150 B, c). At the same time the lower part 

 of the embryo pushes its way down into the tissues of the 

 parent plant, from which it continues to draw food until 



Fig. 151. 



A, archegonium with egg cell at the base 

 of the cavity, and B, antheridium of a 

 moss. At s and t are sperms ; these 

 are seen escaping from the apex of B. 

 All highly magnified. After SACHS. 



