8. F. plàna, Sulliv. Procumbent, widely branching or subpinnate; leaves orbicular, subimbricate; lower lobe very small, as broad as long, close to the stem; underleaves rather large, flat, rounded, slightly bifid; monœcious; perianth oblong-oval or subobovate, triquetrous, dorsally sulcate, acutely keeled ventrally; antheridial spikes globose.—Shaded rocks, N. Y. and N. J. to E. Tenn.
9. F. dilatàta, Nees. Loosely and widely pinnate; leaves round, entire, opaque; lower lobe subrounded, cucullate, close to the stem; underleaves subquadrate, toothed at the anterior angles; involucral leaves with 2 or 3 entire lobes; perianth tuberculate, retuse.—Rocks and trunks of trees; rather common. (Eu.)
§ 2. THYOPSIÉLLA. Perianth smooth; leaves semicordate at base (marked by a central moniliform row of cells, or sometimes in n. 12 by a few scattered large cells); lower lobe near the stem (except in n. 11), cylindric-saccate, mostly erect; underleaves round-oval, the margin entire, recurved; diœcious.
[*] Leaves orbicular.
10. F. Asagrayàna, Mont. ([Pl. 24.]) Creeping, simply pinnate; leaves concave, obtuse, decurved; lower lobe oblong-clavate, emarginate at base; underleaves oblong, flat, 2-cleft, the sinus obtuse; involucral leaves unequally 2-cleft, the dorsal segment oblong, pointed, nearly entire, the ventral subulate; perianth pyriform, 3-sided, obtusely keeled beneath. (F. Grayana of authors.)—Rocks and bark of coniferous trees; frequent.
11. F. Tamarísci, Nees. Bipinnately branching, somewhat rigid; leaves obtuse, mucronately acute or subacuminate, decurved, entire; lower lobe distant from the stem, oval or oblong; underleaves quadrate-ovate or obovate, emarginate, the margin revolute; involucral leaves bifid, serrulate; perianth oblong, sulcate dorsally, obtusely keeled ventrally.—N. Eng. and southward; rare. (Eu.)
[*][*] Leaves oblong from a narrowed base.
12. F. fragilifòlia, Tayl. Procumbent, subpinnate, the alternate flattened branches subremote; leaves subimbricate, ascending, recurved, entire; lower lobe oblong-galeate; underleaves round-obovate, flat, appressed, bifid, the margins entire or angled; perianth obovate-cordate, concave dorsally, keeled ventrally; involucral leaves subequally lobed, obtusely few-toothed. (F. polysticta, Mont. F. Sullivantiæ, Aust.)—On trees in a cedar swamp, Urbana, Ohio (Sullivant). (Eu.)
2. JÙBULA, Dumort. ([Pl. 25.])
Characters nearly as in Frullania. Leaves large and flat, an axillary one at the base of each branch without a lower lobe. Calyptra turnip-shaped, abruptly globose above. Monœcious, with 2 antheridia in each leaf of a spike-like branch, and the archegonia mostly solitary. (Name from juba, a mane, alluding to the persistent elaters.)