2. Homalia Brid. 扁枝藓属 bian zhi xian shu
Bryol. Univ. 2: 812. 1827. (‘Omalia’, nom. & orth. cons.). Leskea subg. Omalia Brid., Bryol. Univ. 2: 329. 1827. Omalia (Brid.) Schimp. in B.S.G., Bryol. Eur. 5: 53. 1850. Hypnum sect. Omalia (Brid.) Müll. Hal., Syn. Musc. Frond. 2: 233. 1851. Neckera sect. Omalia (Brid.) Mitt., J. Proc. Linn. Soc., Bot. Suppl. 1: 117. 1859. Homalia (Brid.) Schimp., Syn. Musc. Eur. 571. 1860, hom. illeg. incl. gen. prior.
Plants yellowish green, dark green when old, glossy, in small to large, loosely or densely flattened mats. Primary stems creeping, with deciduous leaves and brownish rhizoids; secondary stems erect-patent or pendulous, irregularly pinnately or irregularly branched; usually without flagelliform branches; pseudoparaphyllia absent; oval in stem cross section, a central strand absent. Leaves complanately appressed, broadly ovate to oblong-ovate, spathulate, or oblong-lingulate, not undulate, obtuse, rounded or apiculate at the apex, narrowed at the base, slightly decurrent, distal margins often incurved at the base; leaf margins entire, or serrulate at the apex; costae single, reaching above the mid-leaf, sometimes double, rarely absent; leaf cells mostly thick-walled; upper cells hexagonal or rhombic; median and lower cells elongate, rhomboidal, narrowly rhomboidal to linear-rectangular. Autoicous or dioicous. Inner perichaetial leaves shortly sheathing at the base, narrowly lanceolate at the apex. Setae elongate, smooth; capsules oblong-ovoid to cylindrical, reddish brown, erect or inclined; opercula conical, with an oblique beak; annuli often consisting of 2 rings of inflated cells; peristome double; exostome teeth yellow or reddish yellow, lanceolate, hyaline at the apex, densely obliquely striate below; endostome segments yellow, plicate, perforate, finely papillose; basal membrane high; cilia 1–3, or sometimes rudimentary. Calyptrae cucullate, usually smooth. Spores spherical, roughened to papillose, rarely nearly smooth.