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 

 sporophyte. lA, calyptra removed, showing capsule, whicji has curved-to 

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

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

 moved, showing the teeth-like peristome and the epiphragm, 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; 0, operculum; t, annulus; p, peri- 

 stome; e, epiphragm; o, apophysis. 3^, stoma of apophysis. 3B, cross- 

 section of capsule — sp, spore-forming cells. 4^, portion of mouth of cap- 

 sule, showing position of peristome and epiphragm in dry weather. 4B, 

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

 — H. O. Hanson. 



