2. Meesia triquetra (Richt.) Ångstr. 三叶寒藓 san ye han xian
Nova Acta Regiae Soc. Sci. Upsal. 12: 357. 1844. Mnium triquetrum L. ex Richt., Codex Bot. Linn. 1045. 1840. Type: Europe.
Meesia triquetra fo. crassifolia Kab., Hedwigia 77: 133. 1938.
Plants yellow to yellowish green, sometimes dark green or brownish green, usually dark brown at base, compact or in loose tufts. Stems erect, 3–6 cm high, not branched or sometimes with 1–3 branches, with dense brownish rhizoids at base; triangular in cross section. Leaves clearly in 3 ranks, broadly ovate-lanceolate, 2.5–3.5 mm × 1.0–1.5 mm, decurrent at base, keeled, squarrose above mid-leaf; margins plane, clearly serrulate; costae strong, percurrent or shortly excurrent; apical cells small, irregularly quadrate or shortly rectangular, green; basal cells rectangular, hyaline, thin-walled. Dioicous. Perichaetial leaves not elongate. Setae 8–10 cm long, straight, reddish brown; capsules ca. 4–6 mm long, with elongate neck as long as the urn; endostome segments linear; basal membrane low. Spores 30–45 µm in diameter, yellowish brown, densely papillose.