二籽薹草 er zi tai cao

Rhizome slender, creeping, branching. Culms 30-50 cm tall, acutely trigonous, weak, scabrous above. Leaves shorter than culm, blades bright green, linear, 1-1.5 mm wide, flat, soft. Involucral bracts setaceous at base, glumelike above. Spikes 2-5, androgynous, distant, globose, with 1 or 2 male flowers above and 2 or 3 female flowers below. Female glumes pale, ovate, 2-2.5 mm, 3-veined costa forming a short mucro. Utricles brown, slightly longer than glume, elliptic, biconvex, 2.5-3 × 1.3-1.5 mm, leathery, lustrous, many veined on both faces, base subrounded, spongy, shortly stipitate, apex abruptly contracted into a smooth beak up to 0.25 mm, orifice emarginate. Nutlets reddish brown, tightly enveloped, elliptic, biconvex, 1.5-1.8 mm, lustrous; style base not thickened; stigmas 2. Fl. and fr. Jun-Jul. 2n = 70.

Swamps, wet places in forests. Heilongjiang, Jilin, Nei Mongol [Russia (Far East, Siberia); N Europe (Scandinavia), North America].