2. Ceratodon Brid. 角齿藓属 jiao-chi xian shu
Bryol. Univ. 1: 480. 1826.
Plants small to medium-sized, green to yellowish green, in dense tufts. Stems erect, simple or branched; central strand present. Leaves appressed, contorted when dry, lanceolate or narrowly ovate-lanceolate, gradually acuminate; margins distinctly reflexed or revolute, notched or irregularly serrulate near the apex; costa single, subpercurrent to shortly excurrent; laminal cells quadrate to short-rectangular, thick-walled, smooth, not much differentiated from apex to base. Dioicous. Perichaetial leaves highly convolute-sheathing at base, gradually narrowed into a short, slender acumen. Setae elongate, straight; capsules suberect and nearly symmetric or strongly inclined to horizontal and asymmetric, long-cylindric, deeply furrowed when dry, strumose at base; opercula short
conic-rostrate; annuli developed, in 2–3 rows of thick-walled, large cells, revoluble; stomata present; peristome teeth 16, lanceolate, reddish brown within, pale yellowish at the margins, with a low basal membrane, divided nearly to the base, transversally striolate below, papillose above. Calyptrae cucullate, smooth, entire. Spores spherical, yellow, nearly smooth.