524. H. PALUSTRE. Dill. St. creeping; br. ascending, crowded, curved, cuspidate and convolute at apex; l. generally secund, sometimes almost falcate, elliptic-entire, strongly concave, pointed; either nerveless, shortly two-nerved or singly nerved half way; per. l. erect, distinctly striate; caps. ovate, slightly curved; cernuous; lid conical, pointed. Stones and rocks in streams. V. var. β. l. imbricate, not secund. γ. _subsphœricarpon._ l. strongly nerved nearly to apex; caps. roundish ovate, tumid. 525. H. DILATATUM. Wils. (_H. molle_, Bry. Eur.) Plant of somewhat firm growth; l. rotundo-ovate, rather concave, suddenly apiculate, texture very close, areolæ long and very narrow; nerve double, short slender, but well defined (_fide_ G. E. Hunt). Caps. ovate cernuous curved, lid conical. At a low elevation. N. Wales, Yorkshire, Berkshire, Clova, Braemar. 526. H. MOLLE, Dicks. (_H. alpestre_ (?) Bry. Eur., non Swartz.) Very weak and flaccid, the tufts falling to pieces on removal from the water; l. varying from ovate to rotundo-ovate, flat, or sometimes very slightly reflexed towards apex, gradually tapering upwards, or very rarely suddenly apiculate; texture somewhat loose, areolæ larger and wider than in last; nerve rather long and thick, ill-defined, single or double (_fide_ G. E. Hunt). Caps. as above. Great elevations. Ben-mac-Dhui, Ben Nevis. [The above two diagnoses are from a paper by Mr. G. E. Hunt, on Perthshire and Braemar Mosses in Trans. Lit. and Phil. Soc. and Manchester, 1868–9, p. 320.] 527. H. ARCTICUM. Sommerfelt. St. 1–2in. creeping; br. elongate, simple, obtuse; l. spreading, green above, purplish below, small, broadly ovate or roundish, somewhat obtuse, entire, strongly two-nerved about half way, sometimes nerves blended into one; caps. ovate, cernuous, tapering into the seta; lid conical. Alpine rivulets. VI. 528. H. EUGYRIUM. Schpr. St. short, much branched; l. crowded, st. l. drooping on two sides, broadly oblong-lanceolate, shortly acuminate; br. l. flexuoso-falcate, plano-concave, elongate-lanceolate narrower, serrulate at apex; nerve thin, unequally bifid; areolæ vermicular excavate, fulvous, and rectangular at the decurrent angles; per. l., external spreading, internal erect, longly lanceolate, with erose apices; caps. ovate-oblong cernuous, turgid, lid mammillate; annulus broadly bi-triseriate. [Bry. Eur. VI., t. 579. Schp. Syn., 639.] Stones in waterfalls. Summer. N. Wales, Devonshire, Killarney. _b._ Dioicous. 529. H. OCHRACEUM. Turn. St. 2–4in., tufted filiform, sub-erect, sparingly branched; l. yellowish green sub-secund, sometimes falcate, distant, ovate-lanceolate, pointed, concave, nerve forked, extending half way; per. l. squarrose recurved; caps. oblong, tapering at base, cernuous; lid conical. Stones in alpine and sub-alpine streams, &c. V. VI.