9. Heterocladium Bruch & Schimp. 异枝藓属 yi-zhi xian shu
Bryol. Eur. 5: 151. 1852. Hypnum subg. Heterocladium (Bruch. & Schimp.) Lesq., Man. Mosses N. America 317, 320. 1884.
Plants minute to medium-sized, usually dull green or yellowish green, in small mats. Stems creeping, irregularly branched to pinnately branched; paraphyllia few, slender or foliose; pseudoparaphyllia foliose. Stem leaves and branch leaves differentiated; stem leaves erect-spreading when moist or reflexed, leaf base cordately ovate, slightly decurrent, tapering gradually to a narrow point; leaf margins plane, serrulate; costa double, delicate, rarely inconspicuous or single; median cells nearly rectangular; basal cells small, quadrate; upper marginal cells shortly rhomboidal; cell walls smooth or minutely unipapillose to multipapillose; branch leaves rather small, widely ovate, with acute, obtuse or rounded apices, usually imbricate or secund. Dioicous. Perichaetial leaves pale, erect, obliquely spreading or squarrose above. Setae slender, smooth; capsules cylindrical, horizontal, pendent or recurved, with short neck, contracted under the mouth; annuli differentiated; opercula conical, with obtuse apices or beaks; exostome teeth narrowly lanceolate, lightly yellowish to yellowish brown; endostome nearly as long as the teeth, narrowly lanceolate, perforate; cilia well developed, usually 1–3. Calyptrae smooth.