408 HYPNACE/E. 



tumid with the closely imbricated, concave leaves ; bright shining 

 green, often tinged with golden brown. Leaves crowded, erecto- 

 patent when moist, more imbricated when dry, almost always 

 more or less homomallous, frequently strongly falcato-secund, 

 very concave; when dry often somewhat involute at margins, 

 glossy and somewhat striate ; large, those at the middle of the 

 branches f— I line long, widely ovate-oblong, somewhat narrowed 

 and often asymmetrical at the base, rapidly and shortly acuminate 

 or apiculate, the point usually oblique ; margin plane, finely 

 denticulate ; nerve rather strong below, reaching about f of the 

 length of the leaf ; cells very narrow, linear-vermicular, not 

 pointed, the walls firm, 10-15 times as long as wide ; shorter and 

 looser at base ; the angular few, sub-quadrate, not forming 

 defined auricles, yellowish. Leaves at the summits of the 

 branches narrower, more gradually and longly acuminate. 

 Pericha^tial bracts erect, sheathing. Seta slightly papillose in 

 the upper half only, short, $-§ inch. Capsule oval-oblong, 

 turgid, dark ; lid acute. Autoicous. 



Hab. Rocks in and near streams, especially where at times submerged. 

 Frequent. Fr. winter. 



The var. homomallum B. & S. is described as having the leaves falcato-secund, 

 and the branches often curved. This form, in a marked degree, occurs occasionally 

 with the type, but it is only the extreme of a number of common forms with the leaves 

 more or less secund ; it is indeed rare to find this species with the leaves perfectly 

 imbricated and not in some degree homomallous ; and this character, and the shining, 

 concave, shortly pointed leaves, are sufficient as a rule to identify the plant at sight. 

 In colour and aspect it sometimes resembles Hypnuvi eugyrium, with which it often 

 grows, and I have more than once had specimens of the present plant sent me labelled 

 as that species ; apart from microscopical examination, however, there is almost 

 always a greater acuteness of leaf and of branch which will distinguish this species 

 from that. In its robust states it sometimes also resembles B. rivulare, but the leaf is 

 very different in form. 



The fruit is usually produced in great abundance, and the seta, smooth in the 

 lower half or even to above the middle, is one of the distinctive characters of the 

 species. 



It appears probable that the specific name plumosum has been wrongly attributed 

 to this moss, and was originally given to quite a different moss, viz., the one usually 

 known and described above as B. salebrosum, in which case the right name for the 

 present species would be B. pseudoplutnosmii ; there appears, however, to be still 

 some little uncertainty on the matter, and the present plant has so long been known 

 under the name of B. pluvwsum that I have retained that name here. 



14. Brachythecium csBspitosum Dixon (Hypnumcxspitosum 



Wils. ; Scleropodium caespitosum B. & S., Schp. Syn.) 



(Tab. LIII. F.). 



In low soft tufts or patches, of a pale, often silvery green ; 

 secondary stems and branches ascending, curved, slender, 

 crowded, acute, julaceous ; leaves erecto-patent, when dry erect 



