1. Isopterygiopsis muelleriana (Schimp.) Iwats. 北地拟同叶藓 bei di ni tong ye xian
J. Hattori Bot. Lab. 33: 379. 1970. Isopterygium muellerianum (Schimp.) Jaeg., Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1876–77: 441. 1878. Hypnum muellerianum (Schimp.) Hook. f., Handb. Handb. N. Zeal. Fl. 476. 1867. Plagiothecium muellerianum Schimp., Syn. Musc. Eur. 1: 584. 1860. Type: Germany. Southern Tyrol, J. Müller s.n.
Isopterygium nitidulum subsp. muelleri Kindb., Canad. Rec. Sci. 6: 72. 1894.
Orthothecium catagonioides Broth. ex Levier, Nuovo Giorn. Bot. Ital., n.s., 13: 270. 1906.
Plants small, pale green or yellowish green, glossy. Stems prostrate or ascending, usually simple, ca. 2 mm with leaves, complanately foliate; epidermal cells conspicuously enlarged, thin-walled, hyaline; central strand present; pseudoparaphyllia none. Stem leaves and branch leaves similar, complanate, oblong-elliptic, abruptly narrowed to a shortly filiform, flexuose acumen, 1.5 mm × 0.4 mm, not decurrent at base, more or less symmetric, concave, lateral leaves somewhat keeled, asymmetric; margins plane, entire; costae double, short; median leaf cells linear, 60–70 µm × 4.0–4.5 µm, thin-walled; upper cells shorter; basal cells shorter and broader; alar cells not differentiated. Dioicous. Inner perichaetial leaves erect, sheathing at base, ca. 1.2 mm long. Setae ca. 7 mm long; capsules suberect, ellipsoid, 1.2 mm × 0.7 mm; annuli deciduous. Spores not seen.