Tortula atrovirens Lindberg 1864

Tortula atrovirens has a massive pad of bulging cells covering the costa, and may be mistaken for a Crossidium, which, however, has a ventral pad of filaments. It is somewhat similar to T. obtusifolia, which also has weakly differentiated, smooth, somewhat elongate marginal cells, but that species of more mesic climates and more northern latitudes has spatulate leaves lacking an adaxial pad.

Leaves ovate to lingulate, apex broadly acute to rounded, apiculate or mucronate, margins revolute or occasionally plane, often bordered proximally with rectangular cells usually hidden in the revolute margins; costa percurrent or ending in apiculus or short mucro, with an adaxial pad of swollen cells similar to those of the lamina, distally broad, (4-)6(-8) cells across adaxial surface; distal laminal cells subquadrate, 9-13(-18) µm wide, µm, 1:1; strongly papillose. Sexual condition autoicous. Sporophytes exerted. Seta 0.6-1.2 cm. Capsule stegocarpic, not systylius, cylindric to ellipsoidal, erect and nearly straight, urn 0.9-1.5 mm; peristome commonly 210-390 µm, teeth of 32 filaments, weakly twisted, occasionally rudimentary, basal membrane 40-50 µm; operculum 0.5-0.7 mm. Spores 15-18 µm, broadly ellipsoidal, nearly smooth.

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.

Distribution: China, India, Mongolia, Russia, Europe, North and South America, Africa, and Australia.

Habitat: on rocks or thin soil over rocks in dry places.

Grimmia atrovirens Smith in J. E. Smith et al., Engl. Bot. 28: plate 2015. 1809; Desmatodon californicus Lesquereux; D. convolutus (Bridel) Grout

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.

Tortula atrovirens là một loài Rêu trong họ Pottiaceae. Loài này được (Sm.) Lindb. miêu tả khoa học đầu tiên năm 1864.