BRYOPHYTES 



81 



leaves (Figs. 61, B, and 62). These rosettes of leaves in- 

 closing sex-organs have been called moss " flowers/' but they 

 hold no relation to real flowers. In a single one of these 

 moss rosettes both kinds of sex-organs (antheridia and arche- 

 gonia) may occur, or only one kind (Fig. 

 63, B). In the latter case, therefore, there 

 are male rosettes and female rosettes ; 

 and if such rosettes occur on different 

 plants, there are male plants and female 

 plants. 



49. The sporophyte. The sporophyte 

 of a moss is much more elaborate than 

 that of a liverwort. Usually it is long- 

 stalked, the capsule (spore-case) opens 

 by a lid, the spore-bearing region is small 

 compared with the rest of the sporophyte, 

 and the whole structure is very complex 

 (Figs. 64 and 65) ; but it still lives as a 

 parasite on the gametophyte, and is com- 

 monly (and wrongly) called the " fruit" 

 of the moss. 



50. Evolution of the sporophyte. - 

 After the establishment of alternation of 

 generations by Liverworts, the most im- 

 portant fact in connection with Bryo- 

 phytes (Liverworts and Mosses) is the 

 progress made by the sporophyte, which 

 is usually spoken of as its " evolution." 

 It was upon the sporophyte that the 

 whole future of the plant kingdom de- 

 pended, for it is the structure of the sporophyte that de- 

 termines the higher groups. 



First stage of the sporophyte. The simplest sporophytes 

 among the Liverworts are merely spore-cases, consisting of 

 a jacket of sterile cells (cells that do not produce spores) 



FIG. 64. Two moss 

 plants (leafy gam- 

 etophytes) bearing 

 mature and long- 

 stalked sporophytes ; 

 the spore-case on the 

 left is still covered 

 by the cap (calyptra) 

 formed by the arche- 

 gonium; the spore- 

 case on the right 

 shows the lid which 

 drops off and ex- 

 poses the spores. 



