15. SCAPÀNIA, Dumort. ([Pl. 24.])
Leaves complicate-bilobed, the upper lobe smaller, the lower succubous; margins entire or dentate or ciliate; underleaves none. Diœcious. Fruit terminal. Involucral leaves like the cauline but more equally lobed; perianth obovate, dorsally compressed, bilabiate, the mouth truncate, entire or toothed, decurved. Capsule ovate. Elaters long, attached to the middle of the valves. Antheridia 3–20, in the axils of small saccate leaves, which are scarcely imbricate or crowded into terminal heads. (Name from σκαπάνιον, a shovel, from the form of the perianth.)
[*] Leaf-lobes somewhat equal.
1. S. subalpìna, Dumort. Leaves equidistant, imbricate, cleft nearly to the middle, the roundish obtuse lobes denticulate on the outer margin; perianth much exceeding the involucral leaves, obovate from a narrow base, denticulate.—Mountains of N. Eng. (Oakes, Austin); L. Superior (Gillman, Macoun). (Eu.)
2. S. glaucocéphala, Aust. Stems short, cespitose, creeping or ascending, subsimple, with numerous offshoots; leaf-lobes broadly ovate, entire, mostly obtuse and apiculate; involucral leaves sometimes denticulate; perianth small, subcuneate, entire. (Jungermannia glaucocephala, Tayl.; S. Peckii, Aust.)—On rotten wood, N. Eng. to N. Y. and Canada.
[*][*] Lower lobe about twice the size of the upper, except near the summit.
[+] Leaves broader than long; upper lobes rounded or blunt.
3. S. undulàta, Dumort. ([Pl. 24.]) Ascending or erect, slightly branched; leaves lax, spreading, entire or ciliate-denticulate, the lobes round-trapezoidal, equal at the summit of the stem; perianth oblong-incurved, nearly entire, twice as long as the outer involucre.—In woods, damp meadows, and rills; common, especially in mountain districts.—Var. purpùrea, Nees; a form with long lax stems and rose-colored or purplish leaves. (Eu.)
4. S. irrígua, 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.