374 BEYACE.E. [Hypnum. 



In its numerous varieties this species seems to pass into tlie last. Tliere 

 is, however, a constant difference in its more rigid leaves, broader and 

 cordate at base, the costa stouter and percurrent, and the areolation 

 shorter and thick. The capsule is generally more solid, of a uniform 

 brown color, not red at the mouth ; the operculum a little longer, siiarply 

 acute and often rostellate. 



121. H. orthocladon, Beauv. Plants in largo deep some- 

 Avhat loose dark green tufts ; branchlets numerous, erect, 1 or 2 

 cm. long or more : stem-leaves bi'oadly ovate-cordate at base, 

 acuminate, those of the branches narrower, open-erect, concave, 

 entire or obscurely serrulate ; costa thick, subpercurrent ; cells 

 thick, chlorophyllose, subrhomboidal ; pericha3tial leaves erect, 

 the inner membranous, plicate-striate, distinctly and obtusely 

 dentate above, cuspidate by the excurrent very broad costa : 

 capsule large, long-cylindrical, narrowed into a long collum, 

 slightly incurved, cernuous, yellowish brown; i^edicel long, 

 flexuous, red ; oj^erculum large, highly convex, conical-apicu- 

 late ; peristome of IT. serpens; annulus simple, narrow. — 

 Prod. 72; Sulliv. Icon. Muse. 199, 1. 122. H. variicm, Hook. & 

 Wils., Drumm. Muse. Amer. (Coll. II.), n. 142. IT. serjyens, var. 

 varhim, Muell., in part. IT. serpens., var. orthocladon., Aust. 1. c. 



Hab. Margins of swamps and springy places, on the ground, on stones, 

 and decayed logs; very common, and very difficult to separate from the 

 last species. 



122. H. irriguum, Hook. & Wils. Plants drooping, ces- 

 pitose ; stems rigid ; branches subpinnately ramulose : leaves 

 solid, spreading and subsecund, opaque, deltoid-ovate, obcordate 

 or decurrent at base, acuminate, subserrulate, costate to the 

 apex ; basilar areolation much enlarged : capsule oblong or 

 strongly arcuate and contracted below the mouth when dry, 

 pale brown ; operculum as in the last species ; teeth orange 

 below, with a broad hyaline border ; annulus of a triple series 

 of cells. — Wils. Bryol. Brit. 361. Amblystegium ftuviatile, 

 Bruch &> Scliimp. Bryol. Eur. t. 566, not Swartz. 



Var. spinifolium. Tufts greenish black ; stems long, rigid, 

 thick, immersed, flexuous, prostrate, irregularly pinnate : leaves 

 •appressed, strict, solid, narrower, sublinear, cuspidate by the 

 very thick excurrent costa. — H. fluviatile, James, Proc. Acad. 

 Phil. 1855, 447. II. noterophihmr, Sulliv. & Lesq. Muse. Bor.- 

 Amer. Exsicc. n. 348 ; Sulliv. Mosses of U. States, 78. 



Hab. Niagara Falls, Trenton Falls, and Little Falls, New Jersey; the 

 variety in limestone springs, Pennsylvania {Porter). 



