150 GRIMMIACE^). 



extreme apex still shorter, minute, obscure, bi-stratose. Seta 

 rather short, variable in length, stout, rigid; capsule small, 

 shortly oval, smooth, glossy, after the fall of the lid somewhat 

 urceolate, contracted below the mouth, dark brown, of solid 

 texture; lid straight, subulate, almost as long as the capsule; 

 calyptra scabrous at apex ; peristome teeth lanceolate, 2 or 3-fid ; 

 spreading when dry. 



Hab. On dripping rocks and near waterfalls, in mountains. Not common. Fr. 

 winter. 



Easily distinguished by its brown, rigid tufts and small, almost globose capsules, 

 which are sometimes on very short fruitstalks and almost concealed among the higher 

 innovations. R. protensum is perhaps the species most nearly resembling it, but is 

 easily distinguished by its larger leaves with widely recurved margins. This, as well 

 as the two other species of the Section Dryptodon, is distinguished by its liking for 

 humid, almost aquatic situations. Grimmia atrata also much resembles it, but is 

 more robust with longer lid and calyptra, and the basal areolation much shorter and 

 less sinuose. 



2. Rhacomitrium aciculare Brid. (Bryum aciculare L. ; 

 Grimmia acicularis CM., Braithw. Br. M. Fl.) (Tab. XXIII. I.). 



In coarse tufts, dull dark green, often becoming blackish, 1-3 

 inches high ; stems stout, dichotomously branched, rigid, denuded 

 below. Leaves erecto-patent, imbricated when dry, sometimes 

 sub-secund at apex, large, broadly oval-oblong, sometimes slightly 

 plicate, often rounded at the broad, obtuse summit, which is 

 entire or more or less dentate, not hyaline ; nerve rather narrow 

 at the base, becoming obscure above and vanishing at some 

 distance below the apex ; margin variously recurved. Cells in 

 one layer except in the upper part at margin, which is slightly 

 thickened, roundish-hexagonal or sub-quadrate near apex, below 

 elliptical-rectangular and sinuose, gradually becoming narrow- 

 linear and sinuose at base, a few angular cells broader, shorter, 

 quadrate, but otherwise similar. Seta straight, erect, about 

 £ inch long, dark brown ; capsule erect, brown, elliptical to sub- 

 cylindric, rather narrow-mouthed, smooth, lid longly subulate, 

 almost equalling the capsule ; calyptra smooth ; peristome teeth 

 divided into 2-3 unequal branches. 



Hab. Rocks in streams in subalpine districts. Common. Fr. spring. 



Readily known from all the other species by its broad obtuse leaves which are 

 usually somewhat denticulate above ; indeed, a fair amount of denticulation appears to 

 be the rule rather than the exception, and the var. dmticulatum B. & S. would seem 

 hardly worth preserving as a named form. In habit it is not unlike some forms of 

 Grimmia apocarpa var. rivularis. 



