2. M. emarginàta, Dumort. ([Pl. 23.]) Stems simple or innovating at the summit, rigid, somewhat thickened upward; leaves usually broader than long, round-cordate or subquadrate, lobes obtuse or mucronate, sinus acute; diœcious; involucral leaves 4–8, usually larger, more deeply and acutely emarginate; perianth urceolate, the closed apex splitting into 4–5 triangular lobes; antheridia 2–3, oval, axillary in terminal spikes. (Sarcoscyphus Ehrharti, Corda.)—On wet rocks, chiefly in mountain rivulets, N. Y. and N. Eng. Floating forms are longer with distant leaves. (Eu.)
3. M. adústa, Spruce. Stems minute, clavate; leaves (5–8 pairs) imbricate, round or broadly ovate from a sheathing base, acutely lobed with angular sinus; monœcious; perianth included, campanulate, crenate becoming irregularly lobed; spores punctate; antheridia 1 or 2, oval, in the axils of the lower involucral leaves. (Gymnomitrium adustum, Nees.)—Alpine region of the White Mts. (Oakes, Austin). (Eu.)
26. NÁRDIA, S. F. Gray. ([Pl. 25])
Stems laterally compressed, usually without runners. Leaves succubous, subconcave or flat, the apex rounded, rarely retuse or bidentate; underleaves none (in our species). Monœcious or diœcious. Involucral leaves 2–4 pairs, connate at base. Perianth subcompressed laterally, connate with the involucral leaves. Antheridia terminal on somewhat spike-like stems. (Named for S. Nardi, an Italian abbot.)
§ 1. EÙCALYX. Perianth connate at base with the inner involucral leaves, somewhat surpassing them, 3–8-carinate, the mouth constricted.
1. N. hyalìna, Carring. Creeping, with ascending tips, the branches dichotomous-fastigiate, with claret-colored rootlets; leaves loosely imbricate, decurrent, roundish, repand-undulate; monœcious or diœcious; involucral leaves broader, appressed, one connate with the lower third of the perianth, which is somewhat exserted, obovate, plicate with acute rough angles, rostellate, at length 4-cleft; capsule round-ovate. (Jungermannia hyalina, Lyell.)—On banks in woods, Closter, N. J. (Austin), Ohio (Lesquereux). (Eu.)
2. N. crenulàta, Lindb. ([Pl. 25.]) Prostrate, branching; leaves orbicular, entire, larger toward the involucre and with large marginal cells; diœcious; involucral leaves 2, rarely 3, adnate to the base of the perianth, which is flattened or terete, more or less regularly 4–5-plicate, the angles smooth; mouth much contracted, toothed. (Jungermannia crenulata, Smith.)—On the ground in old fields, N. Y. and southward. (Eu.)
3. N. crenulifórmis, Lindb. Densely cespitose; fertile stems creeping, thickened upward, with numerous purple rootlets, the sterile subascending, attenuate upward; leaves subdecurrent, obliquely spreading, orbicular, concave, entire or nearly so; perianth small, subobovate, more or less connate with the involucral leaves, not exserted or slightly so, rooting at base, triquetrous above, becoming 4–7-plicate; calyptra often violet-purple; capsule oval-globose. (Jungermannia crenuliformis, Aust.)—On rocks in rivulets, Closter, N. J. (Austin), Coshocton Co., Ohio (Sullivant).
4. N. bifórmis, Lindb. Densely cespitose, much branched, innovating from beneath; rootlets numerous; leaves scarcely imbricate, alternate, spreading, obliquely semicircular or broadly ovate, retuse or entire, decurrent dorsally; cells large, hyaline; branch-leaves half as large, ovate or obovate, scarcely decurrent; diœcious; antheridia solitary; fruit unknown. (Jungermannia biformis, Aust.)—On steep wet rocks, Delaware Water Gap, N. J. (Austin).
§ 2. CHASCÓSTOMA. Perianth exserted, subcampanulate and open, deeply laciniate, connate with the involucral leaves.