4. Plagiothecium euryphyllum (Cardot & Thér.) Z. Iwats. 直叶棉藓 zhi ye mian xian
J. Hattori Bot. Lab. 33: 348. 1970. Isopterygium euryphyllum Cardot & Thér., Bull. Acad. Int. Géogr., Bot. 18: iii. 1908. Type: Japan. Oshima, Ferrie s.n.
Plagiothecium splendens Schimp. ex Cardot, Bull. Soc. Bot. Genève, ser. 2, 4: 384. 1912.
4a. Plagiothecium euryphyllum var. euryphyllum 直叶棉藓原变种 zhi ye mian xian yuan bian zhong
Plants medium-sized, pale green or yellowish green, somewhat glossy, in loose mats. Stems prostrate, irregularly branched; leafy branches creeping or ascending, complanate; central strand differentiated. All leaves somewhat asymmetric, slightly contorted when dry, ovate or elliptical, 1.3–2.4 mm × 0.8–1.2 mm, broadly acute, more or less undulate at apex; margins entire below, serrulate near apex; costae double, rather thick, reaching near mid-leaf or slightly above; median leaf cells linear, 80–140 µm × 5–7 µm, thin-walled; apical cells shorter; basal cells broader, thick-walled, porose; alar cells rectangular, hyaline, thin-walled, shortly decurrent, cells of leaf decurrency shortly broad-rectangular, sharply different from other basal cells. Brood bodies as gemmae often consisting of 3–4 cells. Dioicous. Male and female plants similar. Perichaetial leaves shortly ovate-lanceolate, ca. 1.8 mm long, often sheathing at base, median cells 100–150 µm × 10–13 µm. Perigonia bud-like. Setae 15–30 mm long, reddish brown or yellowish brown; capsules inclined to horizontal, ellipsoidal or cylindrical, 2.0–2.5 mm long, nearly symmetric; opercula shortly conic-rostrate, with erect beaks; annuli developed, consisting 2 rows of inflated cells; stomata present at neck; peristome typical for the genus; cilia 2–3. Spores 10–13 µm in diameter, minutely papillose.