489. H. (AMBLYSTEGIUM) IRRIGUUM. Hook. St. procumbent rigid, sometimes pinnate; l. spreading, secund, gradually tapering to a point from a deltoid-ovate somewhat decurrent base, sub-serrulate, strongly nerved nearly to apex; caps. oblong, cernuous, curved, when dry more so, and contracted at mouth; annulus persistent; lid conical, blunt-pointed. Stones in rivulets and streams. IV. 490. H. (AMBLYSTEGIUM) FLUVIATILE. Swartz. St. procumbent, with simple, prostrate, not rigid branches; l. ovate or ovate-lanceolate, acute, entire, concave, strongly nerved almost to apex; caps. slender, elliptical, elongate, sub-erect, only slightly curved; lid conical. Rocks and stones in mountain streams. V. VI. 2. L. areolæ narrow, rhomboido-hexagonal, prosenchymatous at base only, rectangulo–6–gonal. 491. H. (AMBLYSTEGIUM) RIPARIUM. Dill. St. longer, creeping, with sub-pinnate sub-erect branches; l. spreading, sub-complanate, ovate-lanceolate entire, nerved two-thirds or more; caps. oblong-cylindrical curved, cernuous, contracted at mouth when dry; lid conical pointed. Stones, &c., near pools, sometimes in water. V. VI. _Sub-genus_ XII. _eu_-HYPNUM. St. erect or procumbent, sometimes radiculose and pinnate; l. patent, squarrose, or falcato-secund, nerve various or none; areolæ narrowly linear,, often dilated, and transparent at base; caps. incurved cernuous on a smooth seta; lid convexo-conical, mammillate, rarely rostrate; perist. perfect. _Sect. I._ Branches straggling or sub-pinnate; l. squarrose-divaricate or stellate and patent. _a._ Monoicous. 492. H. HALLEKI. L. Jun. St. creeping, with pinnate erect branches; l. crowded lanceolate, recurved from a roundish ovate base, acuminate, serrulate, almost squarrose, faintly two-nerved at base or nerveless; caps. oblong curved cernuous; lid conical, blunt. Alpine rocks, rare. VIII. 493. H. POLYMORPHUM. Hedw. “St. procumbent, branches simple, erect, slender; l. spreading, almost squarrose, sub-secund, ovate-lanceolate, acuminate, entire, nerveless; caps. oblong, curved, cernuous, lid conical.” [Bry. Brit.] Limestone walls, banks and rocks. V. _b._ Dioicous. 494. H. ELODES. Spruce. St. elongate, slender, with sub-pinnate slender sub-erect branches: l. distant, spreading; br. l. lanceolate-subulate, apex almost setaceous, secund; st. l. wider, less secund; all entire, nerved nearly or quite to apex: caps. cylindrical curved cernuous; lid conical. Wet places and bogs. IV. V. [Wilson states the leaves to be sub-denticulate at _base only_, whilst his figure is evidently _serrulate_ above and entire at base. I can find no indications of denticulation, even under a ¼inch, except perhaps an occasional slight protrusion of an odd cell here and there, but this cannot be called even denticulate.]