Description from Flora of China
Schoenus sinensis Handel-Mazzetti.
Perennials. Rhizomes short. Culms tufted, 60-100 cm tall, 2-5 mm thick, subterete, smooth. Leaves basal and cauline. Basal leaves with sheath dark purple to dark reddish purple, 3-4 cm; leaf blade linear, 1-5 mm wide, margin scabrous. Cauline leaves 1-3, remote, rather short; sheath reddish brown, mouth oblique. Involucral bracts leaflike; sheaths brown to reddish brown; basalmost bract with a blade subequaling inflorescence. Inflorescence a narrow lax panicle; branches 2-4-nate, occasionally single. Spikelets brown, narrowly ovoid, 7-14 × ca. 2.5 mm, erect, slightly flattened, shortly pedunculate, 3-8-flowered. Glumes brown with a pale margin, distichous, ovate-lanceolate to ovate, 5-7 mm, papery, glabrous except for scabrous keel, keel yellowish green, apex acute; basal 2 or 3 glumes sterile and smaller. Perianth bristles (0 or)1-3, ferruginous, antrorsely scabrous. Stamens 3; filaments slender; anthers linear, ca. 3 mm, caducous; connective apex appendage white, to 0.5 mm. Style 3-4 mm; stigmas 3, much shorter than style. Nutlet rusty brown, obovoid, 1-1.5 mm, 3-sided, reticulate, apex hirsute with white appressed hairs. Fl. and fr. May-Jul.
Swamps, wet places; ca. 400 m. Guangdong, Guangxi, Guizhou, Taiwan [Indonesia, Japan (Ryukyu Islands), Malaysia, Papua New Guinea, Thailand, Vietnam; N Australia, Pacific islands].