4. Isopterygium minutirameum (C. Müll.) Jaeg. 纤枝同叶藓 qian zhi tong ye xian
Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1876–77: 434. 1878. Taxiphyllum minutirameum (C. Müll.) Mill. & Smith, Micronesica 4: 225. 1968. Hypnum minutirameum C. Müll., Syn. Musc. Frond. 2: 689. 1851. Type: Indonesia. Java, Blume s.n.
Isopterygium subalbidum (Sull. & Lesq.) Mitt., Trans. Linn. Soc. London, Bot., ser. 2, 3: 176. 1891. Hypnum subalbidum Sull. & Lesq., Proc. Amer. Acad. Arts 4: 281. 1859.
Plants slender, pale green or yellowish green. Stems densely and regularly branched; pseudoparaphyllia filamentous. Leaves dense, complanate, triangularly lanceolate, ca. 1 mm × 0.25 mm, gradually acuminate; margins plane; costae indistinct; median leaf cells linear, 80–90 µm × 4.0–4.5 µm, thin-walled; apical cells broader, apices formed by uniseriate or biseriate cells; basal cells shortly rectangular or subquadrate; alar cells indistinct. Autoicous. Inner perichaetial leaves sheathing at base, gradually acuminate, ca. 1 mm long. Setae ca. 12 mm long; capsules inclined, shortly cylindrical, 1.0–1.3 mm × 0.5–0.6 mm, with a neck; opercula conic, bluntly and shortly rostrate. Spores 9–12 µm in diameter.