Jennings: Manual of Mosses — 31. Hypnaceae 239 



aduncus. Grout suggests that Sendtneri is a calcicolus form of adiincus, which 

 it parallels in many of its forms. 



In wet Hmy bogs, swamps, etc. Eurasia, and, in North America extending 

 from Canada south to North CaroHna, and in the west to California. 



7. Drepanocladus fluitans [Linnaeus] Wamstorf 



{Hypnum ftuitans Linnaeus; Amblystegium fiuilans DeNotaris) 



Plate LXIX 



Loosely and softly cespitose, yellowish to dark brown, irregularly to regu- 

 larly pinnately branched: leaves more or less secund or falcate, narrowly lan- 

 ceolate to oblong-lanceolate, tapering gradually into a very slender flexuose 

 acumination, the branch-leaves somewhat narrower than the stem-leaves but 

 quite similar, all denticulate, excavate at the base, sometimes reaching a length 

 of 4 mm, decurrent; costa not markedly wide, reaching into the ap>ex or at least 

 nearly so; leaf-cells about 20-30:1, long, reaching to .100 mm or more, 

 pointed, narrow, somewhat incrassate, the alar, hyalme or colored and often 

 forming more or less distinct auricles reaching sometimes to the base of the 

 costa, somewhat inflated: seta red, long, up to 5 or 6 cm or sometimes much 

 longer, flexuous, strongly dextrorse; capsule more or less inclined, curved, 

 rather thin-walled, with a distinct collum, about 3-4:1; lid high-convex, bluntly 

 apiculate; peristome-teeth rather short, segments rarely carinately split, cilia 

 usually 1 or 2, usually considerably shorter than the segments: annulus none; 

 spores mature in early summer. Very variable and split up into many forms 

 and varieties by various authors. 



In ditches, swamps, bogs, stagnant pools, among willows, cat-tails, etc., 



often immersed or floating, almost cosmopolitan in temperate and cold regions; 



in North America, throughout Canada and the northern United States. 



Centre Co.: Bear Meadows. T. C. Porter. (Porter's Catalogue). Erie Co.: En- 

 tirely submerged in lily pond. Presque Isle. Nelle Ammons. July 13, 1935. McKean 

 Cc: In stagnant water. West Branch Swamp, Bradford. Among willows. D.A.B. May 

 26, 1895 (figured) and June 9, 1895. Somerset Co.: Pleasant Union, Sept. 7, 1942; 

 and Mt. Davis Fire Tower, eiev. 3210 ft., Sept. 21, 1947. C.M.B. 



8. Drepanocladus exannulatus (Guembel) Wamstorf 



{Hypnum exannulatum Bryologia Europaea; Amblystegium 

 exannulatus DeNotaris ) 



Plate XLIV 



Typically more rigid, compact, and more completely pinnate than D. 

 fluitans. the leaves more falcate, usually serrulate, frequently striate, especially 

 when dry: the costa reaching well towards the apex and rather stronger than 

 in D. fluitans, biconvex; the alar cells hyaline and much enlarged, forming 

 an excavate and well defined excavate auricle extending across to the costa. 

 In our region the specimens show the following characteristics: yellowish- 

 brown, floating, the stems up to 8 or 10 cm long, the tips of stems and 

 branches hooked; leaves rather remote, reaching 4 mm long, irregularly and 

 widely spreading, not definitely circinate or secund, except at the tips of stems 



