328 BRYACEiE. 



These two groups are fairly natural, and there will be no 

 difficulty as a rule in determining to which of them a given plant 

 belongs, although the characters above defined do not all hold 

 good in every species. It may be borne in mind that all the 

 species with longly excurrent nerve, and all those with long cap- 

 sules (2 lines or more) fall within (I.) ; and that the only species 

 in that group which have the leaves obtuse (B. neodamense) , or 

 very shortly pointed (B. bimum and B. pseudo-triquetrum) , are 

 at once referable to it from their robust habit and long capsules]. 



(SUB-SECTION I). 



15. Bryum bimum Schreb. (XLIV. C). 



Robust, tall, 2-6 inches high, pale green to purplish, stems 

 stout, loosely or densely tufted, usually interwoven with brown 

 tomentum. Upper leaves forming a large comal tuft, long, i-i| 

 lines or more, erecto-patent or spreading, straight, when dry 

 usually shrunken, somewhat twisted or appressed, oblong-lanceo- 

 late or lanceolate, tapering to a short point, from a wide, often 

 slightly expanded red base ; margin strongly recurved nearly to 

 the summit, slightly denticulate at apex or entire ; leaves on the 

 barren branches sub-equal, often distant, wider, more flaccid ; 

 nerve strong, reddish, reaching apex and usually shortly excurrent 

 in a denticulate cuspidate point ; cells rather smaller than in 

 most of the previous species, rhomboid-hexagonal, narrower 

 towards the edges of the leaves, 3-4 rows at margin very narrow, 

 forming a distinct, often yellowish border. Seta long, i-2\ inches, 

 curved or bent at the top so that the capsule is sub-pendulous or 

 inclined ; capsule long (2-2^- lines), large, bright brown, clavate 

 or sub-cylindric with a long tapering neck often nearly as long as 

 the capsule, often curved slightly upwards, rarely downwards, 

 very slightly contracted below the mouth when dry, lid large, 

 conical, acuminate ; peristome large. Synoicous . 



Hab. Bogs and pools ; not uncommon. Fr. summer. 



A fine species, not likely to be confounded with any other except B. pseudo- 

 triquetrum, on account of the robust habit, the large leaves with short points, and 

 large, long capsule on a tall seta, and the synoicous inflorescence. It varies much in 

 habit and size, being occasionally found with exactly the habit of B. pseudo-triquetrum, 

 but more commonly of a paler, green colour, with long, lax-leaved innovations, and 

 soft, flaccid leaves. The capsule also varies considerably in size and length. 



