4. Brachymenium immarginatum C. Gao & G.-C. Zhang 无边短月藓 wu bian duan yue xian
Acta Phytotax. Sin. 17: 116. 1979. Type: China. Xizang, Zhong-ba Xian, alt. 4600 m, Qinghai Xizang Team 7850(1) (holotype IFSBH).
Plants very small, 3–4 mm high, bright green or yellowish green, not glossy, not forming rosettes. Stems simple, rarely branched, with dense brownish rhizoids at base. Leaves often crowded at top, lower leaves smaller, upper leaves larger, oblong-ovate or ovate-lanceolate, not decurrent at base, bluntly acute at apex; margins entire, borders not differentiated; costae slender, ending in the leaf apex; median leaf cells obliquely quadrate to rounded hexagonal, basal cells narrowly rectangular. Dioicous. Setae reddish brown, 10–15 mm long; capsules erect or inclined, elongate-ovoid, neck not clearly differentiated; mouth narrowed; peristome double; exostome teeth lanceolate; endostome segments reduced, with indistinct basal membrane; cilia absent. Spores 23–28 µm in diameter, papillose.