BRYEI. 205 



58. ORTHODONTIUM, Schwcey. 



Sporangium symmetrical ; spore-sac small ; peristome 

 double ; external of sixteen rather distant teeth, inner a mem- 

 brane divided almost to the base into sixteen processes, with- 

 out intermediate cilia. Delicate, perennial, tufted Mosses, with 

 very narrow leaves. 



1 . O. gracile, Schwcsa. ; monoicous ; leaves crowded, spread- 

 ing, linear, setaceous, very obscurely toothed above ; nerve 

 reaching almost to the apex; sporangium inclined, elongated, 

 clavate, with a long tapering apophysis ; lid with a short beak. 

 Hook. % Wils. t. xlvii. ; Eng. Bot. t. 2835.; (Plate 18, 

 fig. 4.) 



On sandstone rocks. Cheshire and Yorkshire. 



Forming somewhat pulvinate, bright-green tufts. Leaves 

 more or less waved ; leaf-cells rather large ; antheridia in the 

 axils of the leaves ; spore-sac separated from the walls of the 

 sporangium ; ring obsolete ; peristome inserted deeply within 

 the mouth ; the outer teeth much more irregular than in 

 Bryum, and not seen at all when the sporangium is dry; 

 spores rather large, yellowish. 



59. AULACOMNION, Schwag. 



Sporangium furrowed when dry; peristome almost as in 

 Bryum; spores very small. Perennial Mosses, growing in 

 marshes or dry ground, and bearing terminal globular masses 

 of gems. 



1. A. androgynum, Schwceg. ; dioicous; leaves lineari-lan- 

 ceolate, irregularly toothed at the apex ; leaf-cells papillose on 

 either surface ; sporangium oblong, regular, slightly cernuous ; 

 male flowers gemmiform. Hook. Wils. t. xxviii. ; Eng. Bot. 

 t. 1238. ; (Moug. $ Nest. n. 620.) 



