THE ARCHEGONIAT^E 



235 



c. 



Fia. 198. Funaria hygrometrica. A, young, B, older, stoma, from the base of the 

 capsule. C, section of a stoma (X 360). 



the inner and outer walls of rows of cells extending from the edge 

 of the theca, under the operculum. The peristome is highly hygro- 

 scopic, and as the water evaporates on the sporophyte approaching 

 maturity, the outward pressure of the peristome helps to throw off 



FIG. 199. A, Barbula fallax, upper part of capsule, showing the slender, twisted 

 teeth of the peristome (X about 20). B, Fontinalis antipyretica, showing double 

 peristome. (After SCHIMPER.) C, Polytrichum commune, peristome and epi- 

 phragma (X 8). D, P. commune, ripe capsule; 1, with, 2, without, the calyptra 

 (X3). 



