BRTOPHTTA. 



703 



away the spores are ripe, and the columella, &c., have dried up and collapsed. The 

 teeth of the peristome are exceedingly varied in pattern in the various genera of 

 Mosses; typically there are two series of them forming an outer and an inner peri- 

 stome (c/. fig. 397 *), but they are difierently thickened, fused, and divided, and one 

 or even both series (e.g. Gymnostomum), may be absent. They are very hygro- 

 scopic, and their function will be alluded to later on when we are discussing the 



Fig. 399.— Spore-capsules of Mosses. 



■* Splachnum luteum. 2 An unripe capsule of the same. 3 A ripe and open capsule of the same. * Splachnum vasculosuTn. 

 ^ longitudinal section of a ripe capsule of this moss, showing the large apophysis below containing lacunas, and traversed 

 in the middle by the columella ; above is the capsule proper with persistent columella, spore-sac, and peristome. 

 8 Splachnum ampullaceum. ' An unripe capsule. 8 A ripe capsule of the same. 9 and lo Schistostega osmundacea. 

 " A ripe capsule of the same. '■, \ «, lo natural size ; 2, s x 2 ; ', «, » x 10 ; n x 16; s x 100. 



■distribution of spores. In the Polytrichese the peristome is not quite the same as in 

 ■other Mosses. In this group the teeth are very numerous and quite short, and from 

 their apices a membrane (the epiphragm) remains stretched after the fall of the lid 

 (c/. fig. 397 *). The spores here tumble out between the teeth. 



The position of the sporogonium is of course determined by that of the female 

 "flowers"; where these are terminal the sporogonium will be terminal (acrocarpous), 

 wmilarly where lateral (pleurocarpous). The number of genera of Bryacese is so 



