118 



MANUAL OF BOTANY 



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

 cyhndrical 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. 877. 



/'/;/. 876. A. Aidoromnion and roijuintm, showing g&mm.tQ borne upon a long 



stalk, r.. Collection of gemmaj more magnified. /''/'/. 877. Funnria 



hiitjrometrim. A. Young sporogonium. c. Capsule, u. Adult condition of 

 the gametopliyte. s. Stalk or seta of the sporogonium. /. Capsule or theca. 

 0. Ca'yptra. c. Section of a sporogonium x8tt. d. Operculum. 2'- Peri- 

 stome. //. Air space. .<••. Sporogenous layer. After Sachs. 



the spores from the capsule are the opercidum 9a\dii\\e 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 from the amphithecium just 

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

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



