5. Weissia exserta (Broth.) P.-C. Chen 东亚小石藓 dong-ya xiao shi xian
Hedwigia 80: 158. 1941. Hymenostomum exsertum (Broth.) Broth., Nat. Pflanzenfam. I(3): 386. 1902. Astomum exsertum Broth., Hedwigia 38: 212. 1899. Type. Japan: Kiushiu, Nagasaki, Wichura 1396.
Plants small, 4–10 mm high, bright green to brownish green, in dense tufts. Stems erect, often irregularly branched. Leaves often crowded at stem tips, contorted-curved when dry, erecto-spreading when moist, narrowly lanceolate, sheathing at base, upper lamina often channeled, acuminate at apex; margins strongly incurved above the leaf base, crenulate by projecting papillae or serrulate near apex; costa rather stout, shortly excurrent, ending in sharply mucronate tips; upper leaf cells rounded-hexagonal, evenly thick-walled, papillose, with bifid or branched papillae; basal cells sharply differentiated, short-rectangular, sometimes forming a V-shaped leaf base, mostly thin-walled, smooth. Autoicous. Setae straight, 1–2 mm long, yellowish brown; capsules erect, oblong-elliptic, exserted.