118 



MANUAL OF BOTANY 



An air space or cavity arises in the former, which extends in-a 

 cylindrical fashion all round the capsule, being crossed by 

 strands or filaments of cells forming a number of bridles. 



The endothecium gives rise to the archesporium, its outer 

 layer being transformed into it. The remainder of its tissue, 

 consisting of large cells, forms the columella. The archesporium 

 is cylindrical and does not extend across the top of the colu- 

 mella. The walls of the capsule contain chloroplasts. 



The arrangements for causing and regulating the escape of 



Fig. 87G. A. Aidocomnion flHt?rO(/!/num, showing gemmae borne upon a long 



stalk. E. OoUeotion of gemmse more magnified. Fig. 877. Funaria 



hi/gromelrim. A. Young sporogonium. c. Capsule. B. Adult condition ol 

 the gametophyte. s. Stalk or seta of tlic sporogonium. /. Capsule or tlieoa. 

 0. Ca'yptra.- c. Section of a sporogonium x 80. d. Operculum, p. Peri- 

 stome, /i. Air .space, s. Sporogenous layer. After Sachs. 



the spores from the capsule are the operculvAnskudthe peristome. 

 The former is the apical portion of the amphithecium. It is 

 detached from the rest of the capsule by the swelling of the 

 walls of a ring of epidermal cells, the annulus, situated at the 

 point of rupture. This swelling causes the separation of the 

 operculum from the rest of the theca, and the lid falls off. 



The peristome is also developed fi.-om the amphithecium just 

 below the operculum, so that when the latter falls off it forms 

 a kind of fringe round the margm of the opening. The cells of 



