RHACOMITRIUM. 151 



3. Rhacomitrium protensum Braun. (Grimmia aquatica 

 CM., Braithw. Br. M. Fl.) (Tab. XXIII. J.). 



In large, loose, depressed patches, 2-8 inches long ; yellowish 

 green, brown below ; stems rigid, procumbent, much branched ; 

 often curved when dry. Leaves erecto-patent or sub-secund, 

 appressed and straight when dry, from a wide oblong base shortly 

 lanceolate, at apex rather widely obtuse, quite entire, not hyaline- 

 pointed ; margin widely recurved, not thickened; nerve strong, 

 broad, reddish, reaching to the apex or nearly so ; cells in upper 

 part of the leaf short, sinuosely elliptical, in one layer, minutely 

 papillose, gradually becoming longer and narrower downwards, 

 the angular scarcely distinguishable. Seta short, about 5-inch, 

 appearing lateral by innovation ; capsule oblong-cylindrical, 

 brown, often hidden by the upper branches ; calyptra smooth ; 

 peristome teeth divided into two narrow branches, which are free 

 or slightly cohering. 



Hab. Damp rocks. Frequent. Fr. spring. 



Not unlike Grimmia patens, but usually of a paler colour, and with quite a 

 different nerve. The leaves while narrower and more pointed than in R. aciculare 

 are more obtuse than in any of the other species ; in R. fasciculare they are much more 

 slender and delicate, with a far fainter nerve ; R. ellipticum has them much smaller 

 with the upper cells bi-stratose, and the capsule is much shorter ; R. heterostichum 

 var. gracilescens is usually much more slender, dull green or blackish, with smaller 

 leaves narrower at the tips ; the other species are known by the hair-points. It is 

 sometimes of luxuriant growth, and I have seen the face of a large rock covered with 

 a rich golden green carpet of this moss, the stems 6 or 8 inches long. 



B. EU-RHACOMITRIUM. 



Stems with fasciculate branches and often with numerous 

 fhort lateral branchlets. Leaves usually hair-pointed. Peristome 

 teeth generally divided more than half-way into two filiform 

 branches. 



4. Rhacomitrium fasciculare Brid. (Bryum fasciculare 

 Schrad. ; Grimmia fascicularis C. M., Braithw. Br. M. Fl.) 

 (Tab. XXIII. K.). ■ 



In close, flat patches, the stems short and more or less erect 

 in the centre, prostrate and creeping towards the outside, yellowish- 

 green, with crowded branches and numerous very short lateral 

 branchlets. Leaves patent and flexuose, appressed and very 

 slightly twisted when dry, from an oval-oblong base longly lanceo- 

 late, narrowly tapering, but not very acute and often distinctly 



