VI. 



THE BRYOPHYTES. 



A higher differentiation of root, stem, and leaf distin- 

 guishes the Moss plants from plants of the preceding sub- 

 divisions. There is a distinct alternation of generations 

 from the gainetophyte, the ordinary Moss plant, to the 

 sporophyte, which develops in the archegonium on the 

 female gametophyte and there produces spores. The 

 differentiation into stem and leaf is outwardly quite well 

 marked, but the inner structure shows only slight progress 

 in these directions. Roots are represented by unicellular 

 or multicellular filaments called rhizoids. The stem shows 

 a decided tendency to. the formation of fibro vascular bun- 

 dles. Gonidia are not formed, but gemmce reproduce some 

 of the plants of this subdivision vegetatively. There are 

 no saprophytes or parasites. All the Bryophytes are 

 chlorophyl-bearing plants of holophytic nutrition. Much 

 moisture is necessary to their vigorous life ; hence they 

 are found in shady damp places on the ground, on the 

 lower parts of the trunks of trees, and on rocks. There 

 are two classes. 



CLASS I. THE LIVERWORTS (Hepaticae). 

 CLASS II. THE MOSSES (Musci). 



CLASS I. The Liverworts. The Liverworts are for the 

 most part low, flat, thalloid plants. They grow in moist 

 locations on the earth and on the rocks along streams and 

 ditches, and in great abundance on the soil in damp 

 greenhouses. The common Liverwort, Marchantia poly- 



K>7 



