Description from Flora of China
Carex nipposinica Ohwi.
Rhizome short. Culms tufted, 30-60 cm tall, medium thick, triquetrous, smooth, clothed with bladeless brown sheaths at base, few sheaths disintegrating into fibers. Leaves shorter than culm, blades 3-4 mm wide, flat, rather stiff, sheathed. Involucral bracts longer than culm, leaflike, lowest sheath long, upper ones rather short. Spikes 3 or 4, rather remote; terminal spike male, linear, 1-2 cm, shortly pedunculate; lateral spikes female, oblong or oblong-cylindric, 1-3 cm, densely many flowered, lowest long pedunculate, upper ones rather shortly pedunculate. Female glumes pale, lanceolate-ovate, ca. 2.8 mm, membranous, 1-3-veined, apex acuminate, with an awn. Utricles brown-green, obliquely patent, horizontally patent at maturity, slightly longer than glume, broadly obovate, inflated trigonous, ca. 3 mm, membranous, glabrous, many veined, base broadly cuneate, estipitate, apex abruptly contracted into a short beak, orifice 2-toothed. Nutlets pale brown, yellowish on angles, slightly loosely enveloped, nearly broadly elliptic or broadly obovate, trigonous, ca. 2 mm; stigmas 3, short. Fl. and fr. Apr-May.
Ditch sides, forests, wet places in low-lying lands; 400-1700 m. Anhui, Gansu, Henan, Jiangsu, Jiangxi, Shanxi, Sichuan, Taiwan, Zhejiang [Indonesia, Japan, Korea; Australia, Pacific islands (New Zealand)].