32. Metzgeria. Thallus narrow (1–2´´), ciliate at the margins or on one or both sides.
[*][*] Thallus with an inconspicuous costa or none.
33. Aneura. Thallus rather narrow, mostly palmately or pinnately lobed. Sporogonium rising from the under side near the margin.
31. Pellia. Thallus wider, mostly simple or forked. Sporogonium rising from the upper surface.
1. FRULLÀNIA, Raddi. ([Pl. 24.])
Leaves incubous, complicate-bilobed, the lower lobe usually inflated, helmet- or club-shaped; underleaves bifid, rarely entire, with basal rootlets. Diœcious or monœcious. Fruit terminal on the branches. Involucral leaves 2 or 4, larger than the stem-leaves; perianth 3–4-angled, mucronate. Calyptra pyriform, fleshy. Capsule globose, the lower third solid. Elaters truncate at each end, unispiral, adherent to the valves. Spores large, reddish, minutely muricate. Antheridia most often on a short branch, globose-oblong or cylindric. Archegonia 2–4, long-styled. (Named for Leonardo Frullani, an Italian Minister of State.)
§ 1. TRACHYCÓLEA. Perianth triangular in section, rough with tubercles or scales, or villous; lower leaf-lobe helmet-shaped, truncate at base.
[*] Lower leaf-lobe about three fourths the size of the upper.
1. F. Oakesiàna, Aust. Stems widely branching; fertile branches short; leaves obliquely orbicular, loosely imbricate, the lower lobe rotund, contiguous to the stem; underleaves ovate-rotund or subobovate, little wider than the stem, bifid; involucral leaves more or less connate, equally bilobed, the lobes entire, obtuse; perianth small, subobovate-pyriform, smooth or 1–7-nerved or alate both sides.—White Mts., on stunted spruce and birch trees.
[*][*] Lower leaf-lobe much smaller than the upper.