2. Tetrodontium repandum (Funck) Schwaegr. 无肋小四齿藓 wu-le xiao si-chi xian
Sp. Musc. Frond., Suppl. 2, 1(2): 102. 1824. Tetrodontium brownianum subsp. repandum (Funck) Boulay, Musc. France 209. 1884. Tetrodontium brownianum var. repandum (Funck) Limpr., Krypt.-Fl. Schlesien 1: 110. 1876. Tetraphis repanda Funck, Deutschl. Fl., Abt. II, Cryptog. 17: . ic. 1819. Type. Europe.
Plants very small, budlike, dark green, gregarious or in scattered clumps. Stems erect, 2–3 mm long, slenderly branched at base, with few scale-like leaves and rhizoids at base. Leaves erect, obscurely in 3 ranks, oblong-lanceolate, somewhat concave, bluntly acuminate or rounded obtuse at apex; margins entire; costa very weak, and often absent; upper and median leaf cells irregularly rhomboidal or irregularly hexagonal, firm-walled, smooth; lower cells narrowly rectangular, 20–25 µm × 7–9 µm. Protonematal flaps absent. Autoicous. Inner perichaetial leaves larger, ovate-lanceolate, with entire, incurved margins. Setae elongate, straight, smooth; capsules oblong-ovoid, 0.8–1.0 mm × 0.4–0.5 mm, dark brownish; opercula low-conic; annuli absent; peristome teeth shortly and broadly triangular. Calyptrae long-conic, ca. 1.5 mm long, deeply lobed at base. Spores not seen.