2. Gymnostomum calcareum Nees & Hornsch. 净口藓 jing-kou xian
Bryol. Germ. 1: 153, pl. 10, f. 15. 1823. Type. Germany.
Plants slender, less than 10 mm high, dark yellowish green, in cushions. Stems erect, usually simple. Leaves 0.7–0.8 mm long, narrowly elliptic-lanceolate to ligulate, blunt or rounded at the apex; margins plane, entire; costa stout, ending below the apex; upper leaf cells rounded quadrate, somewhat thick-walled, pluripapillose; basal cells rectangular, thin-walled, smooth, hyaline. Setae slender, 3–4 mm long; capsules ovoid-cylindrical.