BRYOPHYTA. 



703 



away the spores are ripe, and the cokiniella, &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 differently thickened, fused, and divided, and one 

 or even both series (e.g. Gymnostomuvi), may be absent. They are very hj'gro- 

 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 tlie same. 3 a ripe and open capsule of the same. * Splachnum vasculosum. 

 « Longitudinal section of a ripe capsule of this moss, showing the large apophjsis below containing lacunae, and traversed 

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

 6 Splachnum ampuilaceum. ' An unripe capsule, s A ripe capsule of the same. 9 and lo Schistostega osmundacca. 

 11 A ripe capsule of the same, i, *, «, i» natural size ; 2, s x 2 ; ', », « x 10 ; i' x 15; ' 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 ei:)iphragm) 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 coui'se determined by that of the female 

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

 similarly where lateral (pleurocarpous). The number of genera of Bryaceaj is so 



