3. Isopterygium courtoisii Broth. & Par. 华东同叶藓 hua dong tong ye xian
Rev. Bryol. 36: 13. 1909. Type: China. Yue Wan Kiai, Sept. 5, 1908, Courtois s.n.
Plants slender, flattened, silver white. Stems soft, interwoven, subpinnately branched, sometimes bipinnately branched, branches 3–5 mm long. Leaves somewhat biseriate, rounded ovate, slightly concave, 0.6 mm × 0.25 mm, asymmetric, suddenly acute to shortly acuminate; margins entire or only serrulate near apex; costae double, very short or absent; alar cells small, quadrate, hyalin, in 2–3 rows. Dioicous. Setae slender, smooth.