3. Distichium Bruch & Schimp. in B.S.G. 对叶藓属 dui-ye xian shu
Bryol. Eur. 2: 153 (fasc. 29–30. Mon. 1). 1846.
Plants small to large, slender, flattened, green or yellowish green, in dense tufts. Stems erect, often simple, rarely branched, tomentose below; central strand present. Leaves distichous, erect-appressed to erect-spreading, abruptly narrowed from a strongly clasping, oblong-ovate to ovate sheathing base to a short or long, setaceous or subulate acumen, shoulder distinct; margins plane, crenulate above; costa single, stout to rather broad, filling nearly the entire subula; upper (shoulder) cells irregularly quadrate or hexagonal, rather thick-walled, obscure, smooth; basal cells short-rectangular to linear, pellucid, thin-walled. Autoicous or dioicous. Perichaetial leaves similar to the upper stem leaves, but slightly larger. Setae straight, elongate; capsules oblong-ovoid to cylindric, erect, symmetric or inclined and asymmetric, faintly plicate when dry; stomata present; opercula shortly conic-rostrate; annuli differentiated; peristome teeth 16, shortly lanceolate, irregularly divided or perforated, often obliquely striolate or sometimes papillose at the base. Calyptrae cucullate, smooth, entire. Spores spherical, densely papillose.