11. Hygrohypnum Lindb. 水灰藓属 shui hui xian shu
Contr. Fl. Crypt. As. 277. 1872. Amblystegium sect. Hygrohypnum (Lindb.) Braith., Brit. Moss Fl. 3: 17. 1896. Amblystegium subgen. Hygrohypnum (Lindb.) Lindb., Musci Scand. 33. 1879.
Plants medium-sized, usually green or yellowish green, sometimes reddish or golden yellowish, often glossy, in loosely caespitose mats. Stems slender, prostrate, denuded in older parts, sparsely branched or irregularly branched; in cross section cortical cells small, thick-walled, or hyaline, inflated; central strand weakly differentiated; pseudoparaphyllia foliose, few, or absent. Stem and branch leaves similar, spreading or imbricate, sometimes falcate-secund, somewhat concave, ovate-lanceolate or broadly ovate, rounded, apiculate or acute at apex; margins plane, entire or serrulate; costae short, double, often forked unequally, rarely single, extending above mid-leaf; median leaf cells linear-rectangular or vermicular, 30–40 μm × 5–6 μm; alar cells quadrate or rectangular, hyaline or yellowish. Autoicous, rarely dioicous. Inner perichaetial leaves elongate-lanceolate, plicate; costae single or forked. Setae reddish, curved when dry; capsules inclined or horizontal, ellipsoidal, curved, mouth constricted when dry or after dissemination; annuli differentiated; cilia (1–)2–4. Spores 16–19 μm in diameter, papillose.