CHAPTER LXI 



ALTERNATION OF GENERATIONS 



373. Life history of a moss. In the moss plants, the individuals that 

 we ordinarily have in mind when we speak of 7noss bear at the end of 

 a leafy stem a group of sexual organs. Some individuals carry egg- 

 producing organs ; others bear sperm-producing organs (see Fig. 1 48). 







mm 



m 



Fig. 14S. Reproduction in moss 



<7, a leafy moss plant {Hypuwn molltiscitm); b, section cut lengthwise through tip of one 

 of the branches, showing position of air/ies^onia, or egg-bearing organs ; c. single arche- 

 gomum, more highly magnified, showing single large egg cell ; d, enlarged view of 

 anthcridium, or sperm-bearing organ, of Polyirichum foi-mosum, discharging sperm cells ; 

 c, greatly magnified view of sperm cells ; /, tip of leafy plant from the archegonium of 

 which a spore plant has grown, showing stalk and spore capsule 



320 



