4. Epipterygium Lindb. 小叶藓属 xiao ye xian shu
Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 19: 603. 1863. Bryum subgen. Epipterygium (Lindb.) Kindb., Gen. Musc. Frond. 225. 1900.
Plants small, in loose or dense tufts. Stems short, erect, simiple or branched. Leaves (infertile branches) 3–4 rows, with 2 lateral rows and 1–2 dorsal rows; lateral leaves flat, broadly decurrent, rounded-ovate to obovate, narrowed at base, shortly apiculate at apex; margins plane, entire or serrulate in the upper half, borders distinctly differentiated by linear cells; dorsal leaves small, narrower; costae nearly reddish, ending up to the apex; leaf cells lax, thin-walled, hexagonal to oblong-rhomboidal; leaves on fertile branches scarcely differentiated into ranks. Dioicous. Setae somewhat elongate; capsules inclined to pendulous, ovoid to spherical, with short and thick neck; opercula conic-rostrate; annuli broad, not persistent; peristome double; endostome segments perforate; basal membrane high; cilia present, nodose. Calyptrae unknown. Spores minutely papillose.