1. Tortula atrovirens (Smith) Lindb., Ofversigt af Forhandlingar: Kongl. Svenska Vetenskaps-Akademien. 21(4):234. 1864; Grimmia atrovirens Smith, Engl. Bot. 28: 2015. 1809.
Desmatodon atrovirens (Smith). Jur., Laubm.-Fl. Oesterr.-Ung. 136. 1882.
Desmatodon convolutus (Brid.) Grout, Moss Fl. N. Amer. 1: 224. 1939. Trichostomum convolutum Brid., Muscol. Recent. Suppl. 1: 232. 1806.
Plants small, 3–5 mm high, dark green above, brownish green below, in dense tufts. Stems erect, simple, rarely irregularly branched, radiculose below. Leaves contorted-curved or somewhat crisped when dry, spreading when moist, oblong-ligulate or oblong-ovate, slightly concave, 0.3–0.7 mm x 0.1–0.2 mm, rounded-obtuse or mucronate at apex; margins strongly broadly recurved, entire; costa stout, reddish brown, excurrent as a mucro or a very short awn, ventral side of upper costa covered by a massive pad of inflated, papillose cells; upper leaf cells rounded-quadrate to hexagonal, 8–11 µm in diameter, thin- to moderately thick-walled, each cell covered by 2–4 C-shaped papillae; basal cells sharply differentiated, short-rectangular, hyaline, smooth. Autoicous. Setae 2–6 mm long; capsules erect, yellowish brown, cylindrical, 1.0–1.5 mm long; peristome teeth erect, unequally linear-lanceolate, densely papillose, with low basal membrane; opercula conic-rostrate, with a long, oblique beak. Spores 13–22 µm in diameter, minutely papillose.
Type. Europe.
Chinese specimens examined: NEI MONGOL: He-lan Shan (Mt.), Z.-G. Tong 1181, 2132 (X.-L. Bai, 1997). XINJIANG: He-jing Co. Si He 951230 (MO); Wu-su Co. Si He 951121 (MO).
Habitat: on rocks or thin soil over rocks in dry places; Distribution: China, India, Mongolia, Russia, Europe, North and South America, Africa, and Australia.
Illustrations: Zander 1993 (Pl. 85, figs. 5–8).