1. Ptychomitrium dentatum (Mitt.) Jaeg.    齿边缩叶藓   chi-bian shuo-ye xian

Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1872–73: 102. 1874. Glyphomitirum dentatum Mitt., J. Proc. Linn. Soc., Bot. 8: 149. 1864. Type. Japan: “Nagasaki, on rocks, oldham” (lectotype NY); China: “Sam-sa Bay, Alexander 20” (syntype NY).

 

Plants medium-sized, 2–3 cm high, green or yellowish green above, blackish green to black below, in loose tufts. Stems erect or ascending, sparsely branched; central strand well developed. Leaves 3.0–4.5 mm long, incurved when dry, spreading when moist, oblong-ovate to broadly lanceolate with an oblong, sometimes sheathing base, somewhat keeled above, broadly acute at the apex; margins plane, strongly toothed above, each tooth consisting of several cells; costa single, strong, ending just below the apex or subpercurrent; upper leaf cells often obscure, rounded-quadrate to subquadrate, 8–10 µm wide, slightly thick-walled; basal cells rectangular to short-rectangular, 26–39 µm × 8–10 µm, somewhat hyaline, thin-walled. Autoicous. Perichaetial leaves similar to upper stem leaves. Setae straight, yellowish brown, ca. 5.0 mm long; capsules erect, oblong-ellipsoid, ca. 2.0 mm long; peristome teeth reddish brown, linear-lanceolate, bifid nearly to the base, densely or finely papillose; annuli undifferentiated; opercula with short, erect beak. Calyptrae mitrate, reaching middle of capsule, longitudinally plicate, lobed at the base. Spores yellowish green, 10–14 µm in diameter, finely papillose.