MANDAI, OF NATURE STUDY. 139 



to the ground, or brick, or whatever their home 

 may be, until finally, after branching profusely, 

 they give rise to very tiny lateral buds, which, 

 in time, grow into moss-plants that bear the re- 

 productive organs called antheridia and archegonia. 

 The fern plant is asexual, while the moss plant is 

 sexual. 



Though the fern plant has neither male nor fe- 

 male reproductive organs, it is at the same time able 

 to produce spores which fall to the ground and devel- 

 op 5^.ar«a/ plants csHfX^^ prothalia^ from which sexless 

 or asexual fern plants once more arise. 



Now the history of the moss plant, though pro- 

 duced by "alternation of generations," is somewhat 

 different from that of the fern. In the moss, the 

 more conspicious moss plant is sexual. It bears 

 male and female organs, and an egg-cell is fertilized 

 by a male element. The fertilized egg-cell remains 

 attached to the mother plant and develops into a 

 tiny sexual stalk which bears on its apex the spec- 

 ial reproductive cells or spores. These spores fall 

 to the ground as did the fern spores, and there grow 

 into a usually thread-like structure, Xhe. protenema, 

 from which the sexual moss-plants arise from buds. 



In the fern asexual generation was the more 

 conspicuous; in the mosses, the sexual genera- 

 tions are more conspicuous. 



