CHAPTER XVII 

 MOSSES, LIVERWORTS, AND FERNS 



248. Introductory. The mosses belong to the second great 

 division of the plant kingdom, the bryophytes^ which means 

 "moss plants." All small, green plants are commonly called 

 mosses, but when we discover what kinds of plants mosses 

 are, we shall see how incorrect such a general use of the 

 term is. The bryophytes also include another group, the liver- 

 worts, which are peculiar and infrequently noticed plants. 

 The mosses, on the contrary, are extremely abundant and 

 grow in almost all kinds of places. The ferns (pteridopliytes, 

 which means " feather plants," or " fern plants ") constitute 

 the third great division of the plant kingdom and will be con- 

 sidered after the bryophytes. It is so much easier to get clear 

 notions of the bryophytes by a study of the mosses, that we 

 shall give our chief consideration to them, rather than to the 

 liverworts, which are simpler in some ways but less common 

 and less easily studied than mosses. 



249. The moss plant. Careful observation of any common 

 moss will enable one to see that it has green, leaf-like struc- 

 tures arranged around a very small stem. Sometimes also 

 there appears upon this leafy stem a slender stalk with a 

 swollen, pod-like tip, or capsule (fig. 203, (7). In this tip many 

 simple asexuaL-sp_Qres are formed, and if we follow the life 

 round of the moss, beginning with the development of one of 

 these spores, we shall get a good notion of the nature of the 

 structures of the moss plant. 



Upon the germination of the asexual spore there grows 

 from it a filament, or thread, which looks so much like the algse 

 that it is often extremely difficult to distinguish it from them. 



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