Mosses, Ferns, and Horsetails. 291 



the time of its maturity ; that is, until the capsule contain- 

 ing the ripened asexual spores has been formed at its apex. 

 The asexual spores are capable of germination as soon as 

 formed, but, instead of producing a leafy moss plant imme- 

 diately, they first form filamentous outgrowths called pro- 

 tonemata, resembling the filamentous Algae (Fig. 152, A 

 and B). Finally buds (Fig. 152, B) are formed on the 

 protonemata, which develop into the leafy moss plant. 



Fig. 152. 



A, germinating moss spore ; B, protonema produced by further development of A, 

 To the left, near the base, is a bud which is to become a moss plant. After 

 Sachs. 



The life history of a moss exhibits an alternation of two 

 sorts of generations ; the leaf-bearing generation, with its 

 archegonia and antheridia, known as the sexual generation, 

 or gametophyte, and the leafless asexual generation, or 

 sporophyte, namely, the capsule and its stalk, which grows 

 from the fertilized egg in the archegonium and produces 

 spores asexually. It should be observed that the asexual 

 generation in its young state bears chlorophyll, and must 

 therefore be able to manufacture a portion of its food, 

 at least for a time. 



178. Dissemination of Spores. — It will be seen that after 

 the top, or operculum (Fig. 1 50, O), of the sporangium has 



