INTEODUCTION TO CRYPTOGAMIC BOTANY. 493 



Oreadei, mosses of a very different aspect. They are found 

 occasionally in flat countries, but they are far more frequent 

 amongst the mountains, where they are the ornament of many 

 a damp spot. Bartramidula, whose pale pink capsules are 

 very ornamental, is remarkable for the spore-sac being united 

 with the top of the columella, as in Hymenostomum, and a 

 total absence of peristome. In BartraTnia it is likewise occa- 

 sionally absent, and when present may be either single or 

 double. Conostomum, which is the only remaining British 

 genus, has sixteen teeth united above, and forming a cone. 

 C. horeale is a northern moss, and has never been found in 

 Wales. There is, however, a southern hemisphere species, 

 C. australe, which has a longer lid, and less serrated, broad- 

 nerved, bristle -pointed leaves. There is also another minute 

 New Zealand species, and one is foimd at Quito. Cryp- 

 topodium, a New Zealand and Australian genus, is distin- 

 guished by the immersed sporangium and double peristome. 

 The long operculum is shaped as in Bryum, and not as 

 in Bartramia ; the sporangium, moreover, is oval rather than 

 spherical. Bartramidula has been found only in Ireland ; 

 Bartramia abounds in species, and is found over the whole 

 world. B. pulverulenta, a Casapi species, has glaucous 

 leaves like Trichostomum glaucescens. In either case the 

 glaucous matter is entirely extraneous and flocculent, without 

 any distinct structure ; but whether it consists of matter cast 

 off like epithelium from the leaves or not, I have been unable 

 to determine. B. rigida is found in Madeira, and great part 

 of Central or South America, as well as in Europe. B. mar- 

 chica and Halleriana appear in New Zealand, but there 

 are besides several strictly southern representatives. 



24. Oreadei, Br. & Sc, Mont. 



Sporangium small, rounded, borne on a curved peduncle, 

 peristome single ; calyptra dimidiate. 



548. The best known example of this tribe to British botanists 

 is the old Weissia nigrita, now referred by Bridel to Catosco- 

 pium, remarkable for its small, globose, dark, shining spo- 

 rangia, suddenly bent and tapering into the long peduncle. 

 The peristome consists of sixteen irregular lanceolate or trun- 



