THE SPOPvOPHYTE OF THE MOSS 



301 



The lower portion of the spore case has stomata (Fig. 270, D), 

 and there is much chlorophyll-bearing tissue in the moss fruit 



-L t/ 



that is capable of doing the work of photosynthesis just as in 

 Anthoceros. But this sporophjte is, of course, dependent upon 

 the gametophyte for its supply of water, which is taken up 

 through the pointed foot of the stalk that is deeply sunken 

 in the top of the leafy moss plant (Fig. 264, B). The spores 



sc 



E 



FIG. 270. The sporophyte of a common moss (Funaria) 



A, young sporophyte s attached to the leafy moss plant and covered by the calyptra 

 cal. Z>, sporophyte with mature spore case sc and calyptra cal at the tip. C, 

 spore case with calyptra removed: o, the cover (operculum). D, a stoma from 

 the surface of the spore case. E, section of young spore case, showing the 

 cylindrical central region of spore-producing tissue sp. F, the spore-producing 

 tissue in detail. Adapted after Campbell 



are developed in groups of four (tetrads) within spore mother 

 cells (Fig. 270, F, sp), which form a barrel-shaped tissue (Fig. 

 270, E, sp) within the spore case. 



In spite of the immense numbers of species in the Bryales, 

 the order is clearly separated from other groups of bryophytes 

 as a side line of plant evolution, and its families and genera are 

 distinuished by relativel minor differences. 



