36. Weissia Hedw. 小石藓属 xiao shi xian shu
Sp. Musc. Frond. 64. 1801.
Plants usually small, not more than 12 mm high, bright green or yellowish green, in dense tufts. Stems erect, short, simple or irregularly branched; central strand present. Leaves often crowded at stem tips, contorted-curved or crisped when dry, spreading or occasionally reflexed when moist, long-ligulate, oblong- or triangular-lanceolate to narrowly lanceolate, sheathing at base, upper lamina often channeled, sharply acute or acuminate at apex; margins strongly incurved or involute above the leaf base, entire or crenulate by projecting papillae; costa rather stout, usually shortly excurrent, ending in sharply mucronate tips, in cross section 2 stereid bands present; upper leaf cells subquadrate to hexagonal, thin- to evenly thick-walled, papillose, with bifid or branched papillae; basal cells sharply differentiated, rectangular, sometimes forming a V-shaped leaf base, mostly thin-walled, smooth, hyaline. Autoicous or dioicous. Perichaetial leaves not much differentiated from stem leaves. Setae short or elongate, straight, yellowish brown; capsules erect or slightly inclined, oblong-ovoid to oblong-elliptic or cylindrical; annuli none or differentiated, of 2–5 rows of vesiculose cells, persistent; opercula conic-rostrate, with a rather long, straight or obliquely beak, or opercula not differentiated; peristome teeth 16, short or rudimentary, papillose. Calyptrae cucullate, smooth. Spores spherical, yellowish brown to brown, papillose.