MOSSES AND FERNS 



CHAP. 



as is the case in stomata of the ordinary form. As the stoma 



Fig. 113. — Funaria hygrometrica. A, Young; B, older stoma, from the base of the 

 capsule; C, vertical section, X360. 



grows larger, however, the median wall does not grow as fast 

 as the lateral walls, and a space is left between its extremities, 



B. 



A. 



Fig. 114. — Funaria hygrometrica. A, Part of the peristome; 0, an outer tooth; it one 

 of the inner teeth, X85; B, section of the seta, X260; C, cross-section of upper 

 part of calyptra, X52S. 



SO that the two guard cells have their cavities thrown into 

 communication, and the division wall forms a cellulose plate' 



