306 



CAPSULE OF BRYALES 



on has here resulted in the transformation of the upper part of 

 the dome-shaped zone of sporogenous cells into vegetative cells 

 (Figs. 210, 3; 211, 6). The sporogenous tissue is usually sur- 



FlG. 210. The mature sporophyte of Polytrichum: i, moss plant bearing 

 sporophytc. i.-l, calyptra removed, showing capsule, which has curved to 

 one side. 2, capsule, the calyptra, 2.4, removed, showing the operculum or 

 lid and the enlarged apophysis, a, at base. 2B, capsule with operculum re- 

 moved, showing the teeth-like pcristome and the cpiphragm, which has 

 been lifted up at one side. 3, section of nearly mature capsule sp, cyl- 

 inder of spore-forming cells that is surrounded on its inner and outer sides 

 by loosely arranged chlorophyll cells; o, operculum; r, annul us; />, peri- 

 stome; e, epiphragm; a, apophysis. 3/1, stoma of apophysis. 3.8, cross- 

 section of capsule sp, spore-forming cells. \A, portion of mouth of cap- 

 sule, showing position of pcristome and epiphragm in dry weather. 48, 

 peristome pressed down on epiphragm, closing the capsule in damp weather. 

 H. O. Hanson. 



