1. Tetraphis geniculata Grig. ex Mild. 疣柄四齿藓 you-bing si-chi xian
Bot. Zeitung (Berlin) 23: 155. 1865. Georgia geniculata (Mild.) Brockm., Arch. Vereins Freunde Naturgesch. Mecklenburg 23: 90. 1870. Type. Japan.
Plants small, 8–10(–15) mm high, bright green or dark green, in dense tufts. Stems erect, simple, with dense, reddish brownish rhizoids at base. Leaves sparse on lower stem, scale-like, crowded on upper stem, ovate to ovate-lanceolate, 0.6–1.2(–2.0) mm × 0.4–0.7 mm, acute to acuminate at apex; margins plane, entire; costa slender, ending well below leaf apex or sometimes nearly percurrent in upper leaves; upper and median leaf cells irregularly rounded-hexagonal, thick-walled, smooth; lower cells elongate, nearly oblong, less thick-walled. Autoicous. Perichaetial leaves lanceolate, up to 3 mm long. Setae ca. 6.5 mm long, twisted when dry, often flexuous, geniculate in the middle, papillose in the upper part; capsules erect, symmetric, narrowly cylindrical, ca. 2.5 mm × 0.25–0.40 mm, thickened at mouth; opercula long-conic; annuli absent; peristome teeth triangular, inserted below the mouth. Calyptrae brownish, deeply plicate, lobed at base. Spores 14–16 µm in diameter, finely papillose.