Description from Flora of China
Rhizome short. Culms tufted, 30-80 cm tall, slightly stiff, smooth, with red-brown sheaths at base. Leaves subequaling or shorter than culm, blades linear, 3-5 mm wide, flat, margins revolute. Involucral bracts leaflike, surpassing inflorescence. Spikes 3-5; terminal spike male, occasionally with several female flowers at apex, narrowly cylindric, 20-30 mm, with slender peduncle; lateral spikes female, sometimes with male flowers at apex, cylindric, 20-40 × 5-6 mm, with slender peduncles 1.5-3 cm, pendent. Female glumes densely ferruginous flecked, oblong-lanceolate or lanceolate, 2.8-3 mm, membranous, green 3-veined costa excurrent into a mucro. Utricles equaling or slightly longer than glume, oblong-ovate, ca. 2.5 × 2 mm, densely papillose and red-brown glandular, veined, base broadly cuneate, apex abruptly contracted into a short beak, orifice emarginate. Nutlets yellowish brown, slightly loosely enveloped, broadly ovate, biconvex, ca. 2 × 1.5 mm; stigmas 2. Fl. and fr. Mar-Jun.
Moist streambanks and grasslands in valleys; 100-2500 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Henan, Hunan, Jiangsu, Jiangxi, Shandong, Sichuan, Yunnan, Zhejiang [Bhutan, India, Indonesia, N Thailand].