THE BRYOPHYTA 



139 



p.p. 



and columella is called the inner spore-sac. The lid 

 (operculum) is at first continuous with the capsule, but 

 eventually becomes detached by the severance of a ring 

 of cells (the annulus) between lid and wall. 



The apophysis is essentially the assimilating part of 

 the capsule ; beneath the epidermis is a broad zone of 

 chlorophyll-tissue, the cells of which are in many cases 

 of the typical palisade 

 form (see Figs. 63, 

 64). The epidermis 

 bears well -developed 

 stomata, which are 

 in essentials similar 

 to those of the higher 

 plants. In Funaria, 

 however, they gener- 

 ally have the pecu- 

 liarity that the wall 

 between the two 

 guard - cells breaks 

 down at the two ends, 



SO that the part en- FIG. 64. Part of tlie apopLysis of a Moss 



. , r (Bryum) in transverse section, p.p, the 



Closing tne pore IS assimilating palisade parenchyma ; st, 



left Standing up in stoma. Magnified 130. (After Haber- 



JJT J.V landt.) 



the middle of the 



fused guard-cells, like a chimney-shaft passing through 

 a room (Fig. 65). At an earlier stage, however, the 

 stoma is two-celled, just as in vascular plants, and in many 

 Mosses it remains so all through. In other respects these 

 Moss-stomata are quite typical. The guard-cells differ 

 from the ordinary epidermal cells in containing abundant 

 chlorophyll-granules ; the form of the cells, as seen both 

 in surface view and in section, could be exactly matched 



