462 HYPNACE/E. 



Besides the typical and the falcate forms mentioned above there are many others 

 which cannot be described in a work of limited compass ; when submerged the plant 

 often becomes beautifully plumose with spreading leaves, in other cases the leaves 

 are close, more or less erect when dry, very long and very silky. In habit, colour, 

 etc. , this species is nearest to H. aduncum, from which it is usually known by its 

 narrower, more silky leaves, denticulate at margin, more longly nerved, with longer, 

 very narrow cells, almost uniform to the base ; but intermediate forms occur which 

 are often very difficult to separate, especially as they are usually the more submerged 

 forms, and mostly barren ; typical H. fluitans being usually very fertile, and distinct 

 in the autoicous inflorescence. H. uncinatum differs in the pale colour, strongly 

 plicate leaves, etc. ; most of the other species have shorter, wider, more circinate 

 leaves, of a more rigid texture, and in habit and other respects are distinct. 



* Hypnum exannulatum Giimb. (Amblystegium exannulatum 

 De Not.) (Tab. LVII. E.). 



Differs from H. fluitans in the plants usually more compact 

 and rigid, less soft and flexuose, more pinnately branched, 

 mostly of a deeper, often purplish colour ; typically but less 

 commonly green or yellowish ; the leaves closer, more strongly 

 falcate, twisted when dry, not rigidly circinate, glossy at back 

 and frequently plicate, especially when dry, strongly hooked at 

 the tips of the stem and branches, mostly longly and finely 

 acuminate from a usuall)' wider base ; nerve often stronger, 

 usually purplish brown, mostly reaching to or nearly to apex. 

 Cells frequently shorter and wider, but not constantly so, the 

 auricular usually abruptly dilated and very distinct, forming 

 rather large, conspicuous auricles. Dioicous, rarely autoicous. 



Var. /S. purpurascens Schp. Firm, compact, closely pinnate, 

 of a more or less deep purplish colour ; leaves crowded, more 

 shortly acuminate , cells rather short, sometimes very short and, 

 proportionately, wide (var. brachydictyon Ren.), nerve often very 

 strong and thick, 60-90 p wide at base. 



Var. 7. stenophyllum (Hypnum stenophyllum Wils. ; H. 

 exannulatum var. Rotae Schp., Syn.). Usually purple or red, 

 more elongate, less compact and rigid ; leaves less crowded, less 

 strongly falcate, very long and narrow (2-2^ lines), nerve strong, 

 sometimes excurrent in a denticulate point ; cells narrow, very 

 long. 



Hab. Bogs, mostly in more elevated situations than is usual with H. fluitans 

 Common. The var. /3 in mountain bogs ; the var. y in deep bogs and pools, rare. 

 Very rarely fruiting. 



Eypnum fluitans, though by no means absent in elevated situations, is pre- 

 eminently a lowland species, while the sub-species is a more subalpine plant, and is 

 usually readily known by its more compact, pinnate growth, with the leaves crowded 

 and often plicate. It is sometimes very much like H. falcatum in leaf structure, but 

 that species is more yellowish, rarely purple, with the leaves more distinctly plicate 



