36. Fissidens obscurus Mitt., J. Proc. Linn. Soc., Bot., Suppl. 1:138. 1859.
Plants medium-sized to large, green, dark green to brown, in dense tufts. Leafy stems prostrate, 18–50 mm long, 3.2–5.0 mm wide, often with a few branches arising from the axils of leaves, with rhizoids at the base of branches and tufts or rhizoids on the underside of stems; axillary hyaline nodules not differentiated; central strand not differentiated. Leaves in 18–43 pairs, rather loosely arranged, crisped when dry, more or less bent downward when wet; middle to upper leaves lanceolate, ca. 3.6 mm × 0.75 mm, broadly acute at apex; base of dorsal laminae rounded to broadly wedge-shaped; vaginant laminae 1/2 –3/5 the leaf length, more or less unequal; costa stout, but not clearly defined, ending several cells below apex; margins almost entire except for the slightly crenulate leaf apex; cells of apical and dorsal laminae irregularly quadrate, short-rectangular to hexagonal, often rounded, thick-walled, 10–13 µm long, obscure, smooth; cells of vaginant laminae similar to those of apical laminae, but with thicker walls, becoming longer toward base and along costa. Dioicous. Archegonia terminal. Perichaetial leaves linear, without limbidia, 3.7 mm long, 0.25 mm wide. Sporophytes unknown.
Type. India: Khasi Hills, Griffith s.n. (isotype H).
Chinese specimens examined: GUANGXI: Lin-gui Co., P.-C. Wu & Y.-X. Lin 965 (PE, SYS); Long-sheng Co., P.-C. Wu & Y.-X. Lin 774b, 1006 (PE, SYS); Shang-si Co., 1974 Team 2257 (IBSC, SYS); Xing-an Co., 1974 Team 1469 (IBSC, SYS). XIZANG: Mo-tuo Co., Y.-G. Su 4452 (HKAS, NICH). YUNNAN: Chu-xiong Co., Redfearn & S. He 1734 (MO); Gong-shan Co., M.-Z. Wang 9500d (HIRO, PE).
Habitat: on wet rocks or sandy soil; Distribution: China, Japan, Nepal, and India.
Fissidens obscurus is characterized by the absence of a central strand, the obtuse to obtusely acute leaf apices, its costa ending several cells below the leaf apex, and the cells of apical laminae 10–13(–16) µm long, thick-walled, obscure, and irregular in shape.
Illustrations: Pl. 86, figs. 1–10.