1. Actinothuidium hookeri (Mitt.) Broth. 锦丝藓 jin-si xian
Nat. Pflanzenfam. I(3): 1019. 1908. Thuidium hookeri (Mitt.) Jaeg., Ber. Thätigk. St. Gallischen. Naturwiss. Ges. 1876–77: 264. 1878. Leskea hookeri Mitt., J. Linn. Soc., Bot., Suppl. 1: 132. 1859. Syntypes. Nepal: Wallich s.n.; India: Sikkim, J. D. Hooker 1104, 1105.
Actinothuidium sikkimense Warnst., Hedwigia 57: 112. 1915.
Plants robust to very robust, up to 15 cm long, yellowish green above, light brown at base, in large interwoven cushions. Stems erect or ascendant, regularly pinnately branched; branches 2.0–2.5 cm long; central strand absent; paraphyllia dense on stems, few on branches, foliose or branched. Stem leaves gradually narrowed from a broadly ovate to triangularly ovate base to a lanceolate apex, sometimes deeply plicate, ca. 3.0 mm × 1.5 mm; margins grossly serrate, rarely entire; costa stout, ending at leaf middle, base with a few paraphyllia; median leaf cells narrowly rhomboidal, ca. 25–35 µm × 8 µm, thin-walled, smooth or with 1–2 papillae or unipapillose at front corners; apical leaf cells linear, smooth; basal leaf cells strongly pitted; branch leaves densely appressed when dry, erect-spreading when moist, ovate to widely ovate; margins dentate; costa reaching 4/5 the leaf length. Sporophytic features the same as those of the genus.