5. Ditrichum Hampe 牛毛藓 niu-mao xian shu
Flora 50: 181. 1867, nom. cons.
Plants often minute to small, rarely medium-sized or large, yellowish green, in loose or dense tufts. Stems erect, simple or sparsely branched, sparsely to densely radiculose; central strand present. Leaves often homomallous, lanceolate, gradually or abruptly narrowed from a lanceolate or oblong-ovate, sometimes clasping base to a long, slender or setaceous acumen; margins plane or reflexed, entire or serrulate above; costa single, stout, percurrent to excurrent, usually filling most or nearly the entire subula; upper cells subquadrate to oval or elongate, smooth; basal cells rectangular to linear, thin-walled; alar cells not differentiated. Autoicous or dioicous. Perichaetial leaves similar to the upper stem leaves or slightly larger and clasping at base. Setae elongate, slender, straight or flexuous; capsules oblong-ovoid to cylindric, erect to suberect or inclined, symmetric or curved, sometimes striate or furrowed when dry and empty; opercula conic, or shortly rostrate; annuli differentiated, consisting of large cells, revoluble, deciduous or persistent; stomata present; peristome single, 16 teeth, linear or filiform, divided nearly to the base, basal membrane low, papillose. Calyptrae cucullate, smooth, entire. Spores spherical, small, smooth or faintly papillose.