5. Atrichum undulatum (Hedw.) P. Beauv. var. gracilisetum Besch. 仙鹤藓多蒴变种 xian he xian duo shuo bian zhong
Ann. Sci. Nat., Bot., ser. 7, 17: 351. 1893. Type: Japan.
Atrichum obtusulum (C. Müll.) Jaeg., Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1877–78: 453. 1880. Catharinea obtusula C. Müll., Flora 61: 81. 1878.
Atrichum undulatum var. haussknechtii (Jur. & Mild.) Frye in Grout, Moss Fl. N. Amer. 1: 103. 1931. Atrichum haussknechtii Jur. & Mild., Verh. Zool.-Bot. Ges. Wien 20: 598. 1870.
Atrichum undulatum var. yunnanense (Broth.) P.-C. Chen & T.-L. Wan in W.-X. Xu & R.-L. Xiong, Acta Bot. Yunnan. 6: 182. 1984. Atrichum yunnanense (Broth.) Bartr., Ann. Bryol. 8: 20. 1935. Catharinea yunnanensis Broth., Akad. Wiss. Wien Sitzungsber., Math.-Naturwiss. Kl., Abt. 1, 131: 214. 1923.
Atrichum yunnanense var. minus (Broth.) Wijk & Marg., Taxon 7: 288. 1958. Catharinea yuennanensis var. minor Broth., Symb. Sin. 4: 132. 1929. Type: China. Sichuan, Handel-Mazzetti 2014.
Plants rather small, 1–2 cm high. Stems single or rarely branched. Leaves strongly crisped when dry, obliquely undulate when moist, long lingulate, usually 8 mm × 1.0–1.3 mm, slightly broader above the midleaf, acute at apex, spines obliquely arranged on the back; margins bordered by 1–3 rows of elongate cells, bi-toothed; costa single, ending in the acumen; lamellae usually 4–5 rows, mostly 3–6 cells high, only on the ventral surface of the costa; median cells oblong, 17–25 µm wide; basal cells rectangular. Dioicous. Setae slender, straight; capsules cylindrical, 2–5 in tufts; peristome teeth 32; opercula conic, long beaked. Calyptrae cucullate. Spores spherical, 10–17 µm in diameter, verrucose.