[*] Underleaves 2–3-cleft, fugacious.
1. P. porelloìdes, Lindenb. Branches ascending; leaves subimbricate, convex-gibbous, round-obovate, the uppermost repand-denticulate, the rest entire, the dorsal margin reflexed; perianth terminal, oblong-ovate, the mouth compressed, denticulate.—Among mosses in swamps and river-bottoms; common.
2. P. interrúpta, Dumort. ([Pl. 24.]) Prostrate, horizontally branched, copiously rooting; leaves imbricate, horizontal, oval, entire or slightly repand; underleaves lanceolate; perianth terminal, broadly obconic, the mouth compressed, repand-crenulate. (P. macrostoma, Sulliv.)—Moist banks and decayed logs, N. Eng., Ohio, and northward. (Eu.)
[*][*] Underleaves wanting.
3. P. spinulòsa, Dumort. Creeping, branches ascending; leaves remote, obliquely spreading, obovate-cuneate, the dorsal margin reflexed, entire, the ventral and apex spinulose-toothed; perianth rounded, at length oblong, the mouth spinulose.—Shaded rocks in mountain regions; rare. (Eu.)
4. P. asplenoìdes, Dumort. Branched, creeping or ascending; leaves subimbricate, obliquely spreading, round-obovate, entire or denticulate, the dorsal margin reflexed; perianth much exceeding the involucral leaves, oblong, dilated at the truncate or ciliate apex.—In rocky rivulets; common. (Eu.)
21. MÝLIA, S. F. Gray. ([Pl. 25.])
Leaves succubous, semi-vertical, circular, or ovate and pointed; underleaves subulate. Diœcious. Fruit terminal or pseudaxillary. Involucral leaves 2, clasping; perianth ovate-oblong, laterally compressed above a subterete base, the apex at length bilabiate, denticulate. Capsule ovate, coriaceous. Elaters free. Antheridia 2 in the axils of bracts clustered near the apex of distinct branches. (Name from Mylius, an early botanist.)
1. M. Taylòri, S. F. Gray. Stems erect, nearly simple, radiculose; leaves large, convex, orbicular, entire, purplish; cells large; underleaves lance-subulate, entire or subdentate; perianth terminal, oval; calyptra finally long-exserted. (Jungermannia Taylori, Hook.)—Wet rocks, high mountains of N. Eng. and N. Y. (Eu.)
22. HARPÁNTHUS, Nees. ([Pl. 23.])