4. S. irrigua, Dumort. Creeping; leaves somewhat rigid, repand, deeply lobed; lobes rounded, submucronate, the lower appressed, the upper convex with incurved apex; perianth ovate, denticulate. (S. compacta, var. irrigua, _Aust._)--Wet places, N. J., Catskill Mts., mountains of N. Eng., and northward. (Eu.)

[+][+] _Leaves longer than broad; upper lobes more or less acute._

5. S. nemorsa, Dumort. Rather stout, flexuose, creeping at base; leaves rather distant, decurrent on both sides, ciliate-dentate, the lower lobe obovate, obtuse, slightly convex, the upper cordate, acute, concave; perianth densely ciliate; capsule large, roundish-ovate, reddish-brown.

(S. breviflora, _Tayl._)--On rocks, etc., in swamps and rills; common and variable. (Eu.)

6. S. Oakesii, Aust. Leaves obovate, somewhat spreading, often deflexed, closely complicate, convex, the lower lobe coa.r.s.ely dentate, and with deep purple spur-like teeth on the keel, the upper roundish and less dentate; perianth usually dentate.--White Mts. (_Oakes, Austin_).

[*][*][*] _Lower lobes 3--4 times the size of the upper._

7. S. exsecta, Aust. Ascending; leaves subcomplicate, entire, the lower lobe ovate, acute or bidentate, concave, the upper small and tooth-like; involucral leaves 3--5-cleft; perianth oblong, obtuse, plicate.

(Jungermannia exsecta, _Schmidel._)--High mountains, far northward; rare.--Perhaps better retained in Jungermannia. (Eu.)

8. S. umbrsa, Dumort. Stems short, dec.u.mbent, slightly branched; leaf-lobes ovate, acute, serrate; perianth incurved, naked at the mouth.--White Mts.; rare.--The tips of the shoots are frequently covered with a dark ma.s.s of gemmae. (Eu.)

16. DIPLOPHLLUM, Dumort. (Pl. 25.)

Leaves rather narrow, complicate-bilobed, the lobes subequal or the upper smaller, the lower succubous; underleaves none. Fruit terminal.

Involucral leaves few. Perianth cylindrical, scarcely or not at all compressed, pluriplicate, denticulate. (Name from d?p???, _double_, and f?????, _leaf_, on account of the folded 2-lobed leaves.)

1. D. albicans, Dumort., var. taxiflium, Nees. Stems ascending, almost rootless; leaves closely folded, subdenticulate, with a rudimentary pellucid line near the base or none, the lobes obtuse or acutish, the lower oblong-scymitar-shaped, the upper smaller, subovate; perianth ovate, plicate. (Jungermannia albicans and J. obtusifolia of _Sulliv._; not of _L._ and _Hook._)--Under rocks in mountain ravines and on the ground. (Eu.)--The typical form occurs in N. Scotia, distinguished by a broad pellucid median line in both lobes.

17. GEoCALYX, Nees. (Pl. 23.)

Leaves succubous, bidentate; underleaves 2-cleft, with linear divisions.

Fruit lateral, pendent. Involucre simple, fleshy, saccate, oblong, truncate, attached to the stem by one side of the mouth. Calyptra membranous, partly adnate to the involucre. Capsule oblong. Elaters free. Antheridia in the axils of small leaves on spike-like lateral branches. (Name from ??a, _the earth_, and ?????, _a cup_, from the subterranean involucres.)

1. G. graveolens, Nees. Leaves ovate-quadrate, 2-toothed, light green; underleaves oval-lanceolate, cleft to the middle.--On the ground, and rotten logs; not rare. (Eu.)

18. LOPHOCoLEA, Dumort. (Pl. 23.)

Leaves succubous, dorsally decurrent, obliquely ovate-oblong, broadly truncate or bidentate; underleaves smaller, more or less quadrate, bifid or with 4--8 capillary lobes. Dicious or moncious. Fruit terminal on the main stem or primary branches. Involucral leaves 2--4, large, often spinulose; perianth triangular-prismatic, 3-lobed, ciliate or laciniate.

Calyptra short, obovate, at length lacerate above. Capsule oblong-globose. Antheridia mostly solitary in or near the base of ordinary leaves. (Name from ??f??, _a crest_, and ???e??, _a sheath_, from the crested perianth.)

[*] _Underleaves mostly bifid (or 3--4-cleft in n. 1); divisions mostly entire._

1. L. bidentata, Dumort. Stems 1--2' long, proc.u.mbent, spa.r.s.ely branching; leaves pale green, ovate-triangular, acutely 2-toothed, the teeth oblique with a lunulate sinus; moncious; perianth oblong-triangular, lacinate; antheridia 2--3 in a cl.u.s.ter, axillary.--On rocks in shady rills; not common. (Eu.)

2. L. Austni, Lindb. Creeping; leaves uniformly deeply lobed, the lobes and usually the sinus acute; underleaves comparatively small, the lobes subulate; cells small; moncious; antheridia solitary in the upper axils. (L. minor, _Aust._; not _Nees_.)--On roots of trees in woods (_Austin_). Imperfectly known.

3. L. Macounii, Aust. Stems very short, prostrate, ascending at the apex, densely radiculose; leaves suberect, ovate-subquadrate, 2-lobed with obtuse lobes and sinus, or retuse or often entire; underleaves light pink, deeply bifid, the setaceous lobes spreading-incurved; moncious; involucral leaves somewhat oblong, repandly 2--4-toothed at the apex; perianth subobovate, slightly angled.--On logs, Little Falls, N. Y. (_Austin_); Ont. (_Macoun_).

4. L. mnor, Nees. Diffusely branching; leaves pale green, oval-subquadrate, expanded, convex, slightly rigid, equally and acutely bifid with a lunate sinus; underleaves {1/3} as large, deeply bifid, the lanceolate lobes ac.u.minate; dicious; involucral leaves like the cauline; perianth obtusely triangular-plicate at the apex. (L. crocata, _Aust._; not _Nees_.)--On the ground and dry rocks in limestone regions (_Austin_). (Eu.)

[*][*] _Divisions of the underleaves more or less dentate._

5. L. heterophlla, Nees. (Pl. 23.) Stems short, creeping or ascending, much branched; leaves ovate-subquadrate, entire, retuse and bidentate on the same stem; underleaves large, 2--3-cleft; involucral leaves lobed and dentate; perianth terminal, the mouth crested.--On the ground and rotten logs in woods and swamps; very common. (Eu.)

6. L. Hallii, Aust. Creeping, very slightly rooting; leaves subvertical, oblong, cleft nearly to the middle with obtuse sinus and erect mostly obtuse lobes; lower underleaves small, subequally 2-parted with an obtuse sinus, the upper ones larger, with a single tooth on each side or palmately 3--4-parted, the apical sublanceolate and narrowly bifid.--On the ground, Ill. (_Hall_).

19. CHILOSC?PHUS, Corda. (Pl. 23.)

Leaves succubous, dorsally decurrent, mostly rounded and entire; underleaves rooting at the base, usually deeply 2-cleft. Fruit terminal on a very short lateral branch. Involucral leaves 2--6, the outer smaller, the inner variously cut; perianth small, obconic or campanulate, 3-angled and 3-lobed only at the apex, the lobes usually spinose. Calyptra fleshy, subglobose or clavate. Capsule oblong-globose.

Antheridia in the saccate bases of stem-leaves. (Name from ?e????, _a lip_, and s??f??, _a bowl_, from the form of the perianth.)

[*] _Underleaves 4-parted._

1. C. ascendens, Hook. & Wils. (Pl. 23.) Prostrate; leaves large, pale green, ascending, roundish-oblong, slightly emarginate; involucral leaves two, 2-cleft; perianth 2--3-lobed, the lobes long and irregularly lacerate-toothed.--On rotten logs; rather common.

[*][*] _Underleaves bifid._

2. C. pallescens, Dumort. Proc.u.mbent, creeping; leaves flattened, ovate-subquadrate, obtuse or retuse; underleaves ovate, distant, free; involucral leaves two, 2-toothed; perianth deeply trifid, the lobes spinose-dentate, mostly shorter than the conspicuous calyptra.--Mountains of N. Eng. (_Oakes_).

3. C. polyanthos, Corda. Proc.u.mbent, creeping; leaves subascending, ovate-subquadrate, truncate or subretuse; underleaves ovate-oblong, distant, free; involucral leaves 2, slightly 2-toothed; perianth 3-lobed, the short lobes nearly entire, shorter than the calyptra.--Var.

RIVULaRIS, Nees. Larger, more branching, succulent; leaves mostly rounded above; underleaves often divided in halves or wanting.--On the ground among mosses or on rotten logs, common; the variety in shaded rills or still ponds. (Eu.)

20. PLAGIOCHLA, Dumort. (Pl. 24.)

Leaves large, succubous, rounded or truncate above, dentate or spinose or rarely entire, the dorsal margin reflexed; underleaves usually none.

Dicious or moncious. Fruit terminal, or axillary by the growth of offshoots. Involucral leaves larger than the cauline; perianth laterally compressed, erect or decurved, obliquely truncate and bil.a.b.i.ate, the lobes entire or ciliate-dentate. Capsule thick, oval. Elaters attached to the middle of the valves. Antheridia oval, 2--3 in the axils of spicate leaves. (Name from p??????, _oblique_, and ?e????, _lip_, from the form of the perianth.)

[*] _Underleaves 2--3-cleft, fugacious._

1. P. porellodes, 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. interrupta, 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. spinulsa, 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. asplenodes, 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. MLIA, S. F. Gray. (Pl. 25.)

Leaves succubous, semi-vertical, circular, or ovate and pointed; underleaves subulate. Dicious. Fruit terminal or pseudaxillary.

Involucral leaves 2, clasping; perianth ovate-oblong, laterally compressed above a subterete base, the apex at length bil.a.b.i.ate, denticulate. Capsule ovate, coriaceous. Elaters free. Antheridia 2 in the axils of bracts cl.u.s.tered near the apex of distinct branches. (Name from _Mylius_, an early botanist.)

1. M. Taylri, 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.)