4. LeptohymeniumSchwaegr. 薄膜藓属 bao mo xian shu
Sp. Musc. Frond., Suppl. 1, 3(1): 246c. 1828. Anomodon subgen. Leptohymenium (Schwaegr.) Hampe, Ann. Sci. Nat., Bot., ser. 5, 4: 368. 1865.
Plants usually medium-sized, slender, stiff, yellow to brownish green, slightly glossy. Main stems prostrate, sometimes arcuate or erect-spreading, usually irregularly 1–3-pinnately branched, rarely shortly branched; branches round, often with flagelliform branchlets; paraphyllia absent; rhizoids few. Stem leaves and branch leaves similar or differentiated, broadly ovate or rounded ovate, sometimes slightly decurrent at base, usually plicate, shortly acuminate or slenderly acuminate at apex, sometimes slightly curved; margins serrulate above, sometimes involute at base; costae double, reaching to the midleaf or shorter; laminal cells linear, sometimes slightly prorate; alar cells slightly differentiated, shortly quadrate, loose, thin-walled, hyaline; branch leaves smaller, narrowly ovate-lanceolate, sometimes slightly concave, costae double. Dioicous. Inner perichaetial leaves sheathing at base, gradually narrowly acuminate upwards, loosely toothed at apex. Setae thin and elongate, sometimes slightly twisted; capsules ovoid or cylindrical, erect, symmetric, with a short apophysis, light brown; annuli not differentiated; opercula conic, shortly rostrate; peristome double; exostome teeth narrowly lanceolate, yellowish brown, trabeculate, outer surface not cross-striate; endostome segments slightly longer than the teeth, keeled, narrowly perforated, yellowish, usually finely papillose above; basal membrane high. Calyptrae cucullate, smooth. Spores globulose, finely papillose, 17–25 µm in diameter.