Oncophorus wahlenbergii Bridel 1826

A common epixylic species, Oncophorus wahlenbergii may be confused with the more saxicolous O. virens, which has keeled, revolute, non-sheathing leaves that gradually narrow to the subula. A compact, densely tufted arctic-alpine form has been treated as var. compactus and is often found on dry soil.

Plants small to large, 1–5 cm high, yellowish green above, blackish brown below, somewhat shiny, in dense tufts. Stems erect or ascending, usually branched, round in transverse section. Leaves up to 7(–8) mm long, lanceolate from a narrowly obovate, clasping and sheathing base, shoulder distinct, abruptly narrowed to a long, subtubulose or subulate apex, strongly crispate and curled when dry, widely spreading when moist; margins plane or slightly recurved in the upper part, entire below, irregularly and remotely serrulate above the shoulder, usually bistratose above; costa narrow, reddish brown, percurrent to shortly excurrent, somewhat roughened at back above; upper cells small, quadrate or short-rectangular, thick-walled; basal cells in the sheathing base, rectangular to linear-rectangular, 45–75 µm × 14–22 µm, pellucid, firm- to somewhat thick-walled; alar cells not differentiated. Autoicous. Perichaetial leaves erect with longer sheathing base than the stem leaves. Setae terminal, straight, 1–3 cm long, brownish; capsules short-cylindric, contracted below the mouth, strongly inclined to horizontal, slightly furrowed when dry and empty; peristome teeth reddish brown, dicranoid. Spores not seen.

Plants soft, in small, loose tufts, light to very dark green. Stems 1-2.5 cm. Branch leaves strongly crisped and curled when dry, ovate-lanceolate, abruptly subulate, entire or sometimes serrated above, 3-6 mm, subtubulose above, strongly sheathing at base, margins plane; costa mostly percurrent; laminal cells mostly 1-stratose, 2-stratose only at margins; distal laminal quadrate to short-rectangular, incrassate; basal laminal cells elongate, rectangular, incrassate, alar cells not differentiated. Seta (8-)10-15(-21) mm. Capsule pale yellow-brown, furrowed when dry, 0.8-2 mm, peristome bright red. Spores 14-20(-30) µm.

Distribution: China, India, Korea, Japan, Russian Far East, Europe, and North America.

Habitat: usually on rotten wood in subalpine forests, rarely on rocks.

Cynodontium wahlenbergii (Brid.) Hartm., Handb. Skand. Fl. (ed. 10), 2: 113. 1871. Dicranella wahlenbergii (Brid.) Lindb., Acta Soc. Sci. Fenn. 10: 243. 1872. Dicranum virens Hedw. var. wahlenbergii (Brid.) Hüb., Musc. Germ. 231. 1833. Dicranum wahlenbergii (Brid.) Schultz., Syll. Pl. Nov. 2: 149. 1828. Oncophorus wahlenbergii var. japonicus Nog., Jap. Bot. 15: 756. 1939. Oncophorus wahlenbergii var. longisetus Nog., Jap. Bot. 15: 756. 1939. Oncophorus sinensis C. Müll., Nuov. Giorn. Bot. Ital. n. s. 3: 99. 1896. Type. China: Shaanxi, Kuan tou san, Levier s.n. (holotype B, probably destroyed).

Oncophorus wahlenbergii var. compactus (Bruch & Schimper) Braithwaite

Oncophorus wahlenbergii Brid. Bryol. Univ. 1 : 400. 1826
Dicranum Richardsoni Hook, in Drummond, Musci Am. 104. 1828. Dicranum microcarpum Hook, in Drummond, Musci Am. 105. 1828. Dicranum virens Wahlenbergii Huebener, Muse. Germ. 231. 1833. Cynodontium virens Wahlenbergii Schimp. Coroll. Bryol. Eur. 12. 1855. Cynodontium Wahlenbergii Hartm. f. in Hartm. Skand. Fl. ed. 10. 2: 113. 1871. Dicranum Demetrii Ren. & Card. Bot. Gaz. 22: 48. 1896.
Autoicous: one or more male flowers sessile at short intervals below the perichaetium, of several usually pale, acute, or the inner obtuse, ecostate, nearly entire leaves enclosing 5 or 6 antheridia with few paraphyses: plants in rather compact yellowishgreen tufts, reddishtomentose within and 1-2 cm., rarely up to 5 cm., high: stem-leaves up to 5 mm. long, from a short, more or less obovate, erect base abruptly narrowed into a slender, grooved point, crispate when dry, the borders flat or somewhat recurved, more or less serrulate about one half down, or rarely entire and of mostly one layer of cells; costa excurrent, somewhat serrulate on the back above, at the base about one fifth the width of the leaf, in cross-section near the middle showing 5 or 6 guide-cells, the stereid-bands above and below often not very well defined, with outer cells somewhat differentiated; upper cells of the blade smooth on both sides, irregular, angular, mostly slightly elongate, the median ones about 8 m wide, the lower ones long and narrow, those toward the costa sometimes with slightly thickened, pitted walls, the alar cells not distinct or rarely forming a small, quite distinct cluster; inner perichaetial leaves about as long as the upper stem-leaves, clasping about one third up, abruptly narrowed to a slender, rough point: seta yellowish or sometimes red, erect, up to 2.5 cm. long: capsule short, curved, often horizontal, with prominent struma and smooth or finally somewhat furrowed; annulus wanting; lid not quite entire at the base, with an oblique beak about one half as long as the capsule; peristome-teeth dark-reddish, divided about two fifths down and vertically striate almost to the slightly papillose apex, the inner articulations distinct and about 20 n apart: spores minutely roughened, up to 1 6 p. in diameter.
Type locality: Lapland.
Distribution: Greenland and Alaska to Pennsylvania, Ohio, and Wyoming; also in Europe and Asia.

Oncophorus wahlenbergii là một loài Rêu trong họ Dicranaceae. Loài này được Brid. mô tả khoa học đầu tiên năm 1826.

曲背藓（学名：Oncophorus wahlenbergii）为曲尾藓科曲背藓属下的一个种。