17. Brachythecium kuroishicum Besch. 皱叶青藓 zou ye qing xian
Ann. Sci. Nat., Bot., ser. 7, 17: 373. 1893. Hypnum kuroishicum (Besch.) Broth., Hedwigia 38: 238. 1899. Type: Japan. Hokkaido, Prov. Shiribeshi, Faurie 99.
Brachythecium buchananii var. gracillimum Dixon, Rev. Bryol., n.s., 4: 156. 1931.
Plants slender, yellowish green to bright green, in loose mats. Stems elongate, prostrate, 5–7 cm long, irregularly branched, densely foliate, with julaceous branches. Stem leaves imbricate, triangular, 1.08–1.67 mm × 0.60–0.78 mm, concave, plicate, abruptly narrowed, cygneous at apex, cordate, slightly decurrent at base; margins nearly entire; costae ending at mid-leaf; median leaf cells elongate-rhomboidal or nearly linear, 45–60 µm × 6–8 µm, with rounded ends, thin-walled; basal cells quadrate or shortly rectangular; alar regions wide; branch leaves ovate-lanceolate to lanceolate, slenderly acuminate at apex, erect or slightly secund. Autoicous. Perichaetial leaves lanceolate, ecostate. Setae ca. 8–10 mm long, smooth; capsules nearly erect or slightly inclined, elongate-ovoid to shortly cylindrical, necks distinctly developed; opercula conic; peristome double; endostome segments as long as exostome teeth, perforate; cilia short. Spores not seen.