6. Isopterygium saxense Williams 石生同叶藓 shi sheng tong ye xian
Bull. New York Bot. Gard. 8: 369. 1914. Type: the Philippines.
Plants pale green. Stems prostrate, radiculose, subpinnately branched, branches short; in stem cross section outer cortical cells in 2 layers, thick-walled; central strand absent; pseudoparaphyllia filamentous or very linear-lanceolate. Stem leaves ca. 1.0 mm × 0.25 mm, triangular-lanceolate, shortly acuminate; margins entire or slightly serrulate near apex; costae indistinct; median leaf cells 40–50 µm × 5–6 µm; alar cells not differentiated; branch leaves smaller, clearly serrulate. Dioicous. Perichaetial leaves lanceolate, ca. 2 mm long, slenderly acuminate, falcate-secund. Setae 12–14 mm long; capsules pendulous, shortly ellipsoid, ca. 1 mm long, constricted below the mouth when dry, exothecial cells papillose, quadrate, ca. 20 µm wide, thick-walled; stomata lacking; opercula slenderly rostrate; annuli wide; peristome hypnoid. Spores 12–14 µm in diameter, papillose.