Description from Flora of China
Carex cernua Boott.
Rhizome short. Culms tufted, 35-80 cm tall, acutely trigonous, scabrous above, clothed at base with red-brown to blackish brown bladeless sheaths. Leaves shorter than or equaling culm, blades linear, 4-7 mm wide, flat, margins slightly revolute. Lower 2 involucral bracts leaflike, surpassing inflorescence, upper ones setaceous. Spikes 5 or 6, approximate; terminal spike gynaecandrous, 40-60 mm; lateral spikes female, upper 3 with male flowers at base, cylindric, 45-55 × 5-6 mm, with slender peduncles 1.5-6 cm, pendent. Female glumes pale, sparsely ferruginous flecked, obovate-oblong, 4-4.5 mm, membranous, green 3-veined costa excurrent into a scabrous awn ca. 2.2 mm at emarginate or truncate apex. Utricles red-brown, ferruginous flecked, longer than glume, elliptic or elliptic-lanceolate, ca. 3 mm, slightly compressed, densely papillose, base cuneate, apex abruptly contracted into a short beak, orifice entire; stigmas 2. Fl. and fr. Apr-Jun.
Moist soil of ditch sides and roadsides; 200-1300 m. Anhui, Gansu, Guangdong, Henan, Hubei, Jiangsu, Jiangxi, Liaoning, Shaanxi, Shandong, Sichuan, Zhejiang [India, Japan, Korea, Myanmar, Nepal, Sri Lanka, N Thailand, Vietnam].