Description from Flora of China
Carex dineuros C. B. Clarke.
Rhizome short, ligneous, rather stout stoloniferous. Culms densely tufted, 30-85 cm tall, rather stout, obtusely trigonous, scabrid on upper angles, yellowish brown and with bladeless or shortly bladed sheaths at base. Leaves slightly shorter than culm, blades 3-6 mm wide, flat, sometimes slightly revolute on margins, slightly stiff, with 2 distinct lateral veins, scabrous on veins and margins; long sheaths of lower leaves up to 10 cm. Lower involucral bracts leaflike, longer than inflorescence, shortly sheathed, upper 2 or 3 setaceous, shorter than inflorescence, usually not sheathed. Spikes 5-7, lower 1 or 2 slightly remote, upper ones rather approximate; terminal spike male, rarely 2 male spikes, occasionally with few female flowers at apex, oblong-cylindric or cylindric, 1.5-5 cm, subsessile; remaining spikes female, narrowly cylindric, 1.5-6 cm, densely many flowered, lower spikes with slender peduncles and slightly pendent, upper spikes shortly pedunculate or subsessile. Female glumes yellowish brown laterally, green between veins, ovate or narrowly ovate, ca. 2.5 mm, 3-veined, apex subacute and mucronate. Utricles greenish or yellowish green, obliquely patent, nearly equaling glume, elliptic or obovate-oblong, indistinctly trigonous, ca. 2.5 mm, membranous, glabrous, purple punctate, obscurely veined, base cuneate, shortly stipitate, apex abruptly contracted into a very short beak, orifice subtruncate or emarginate. Nutlets tightly enveloped, obovate, trigonous, ca. 1.5 mm, apex mucronate; style base not thickened; stigmas 3. Fl. and fr. May-Jul.
Riversides in valleys, wet places at ditch sides or in forests; 400-1500 m. Hebei, Jilin, Liaoning [Korea, Russia (Far East)].