196 HISTORY OF BRITISH MOSSES. 



rostellate; teetli of the peristome somewhat irregular, the 

 internal ones half the length of the external. Pohlia gracilis, 

 Wils. in Gard. MuscoL Brit. tab. 34. apj^- Orthodontium 

 gracile, Miill. Sijn. jpt. \. p. 238. 



On sandstone rocks near Helsby, Cheshire, Mr. Wilson. 

 Fr. Spring. This interesting Moss was detected by Mr. 

 Wilson in the above locality in 1833, but we are not aware 

 that it has been found elsewhere in the country, though M. 

 Schimper has gathered it on the Abyssinian Alps. 



21. Bryum alpinum, Linn. {Red Alpine Thread Moss.) 

 Stems elongated, rigid, branched ; leaves closely imbricated, 



/ erect, lanceolate, somewhat obtuse, subserrulate at the apex, 

 the margins revolute ; nerve reaching to the points ; cap- 

 sule obloug-ovate, pendulous. — ETig. M. p. 62 ; Mitll. Syn. 

 pt. I. p. 285. 



In subalpine districts, on moist rocks and stones, prefer- 

 ring such as are exposed. Fr. June. The fine reddish- 

 purple colour of this species sufficiently distinguishes it from 

 others. Its foliage is closely imbricated or lapping over, 

 and in a dry state is very glossy. 



22. Bryum ventricosum, Dicks. {Swelling Bog Thread 

 Moss.) Stems elongated, branched with innovations ; leaves 



/ oblong, acuminated, scarcely serrulate, the margins recurved ; 



