扁秆薹草 bian gan tai cao

Rhizome thick and slightly elongate, with slender stolons. Culms tufted, 30-45 cm tall, rather thick, compressed triquetrous, winged on 2 angles and 1 angle obscure, scabrous on angles, few bladeless sheathed at base. Leaves slightly shorter than culm, blades 5-10 mm wide, flat, rather soft, scabrous on veins and margins, ± long sheathed; sheaths brownish yellow, eventually split on membranous part. Lower involucral bracts leaflike, longer than subtending spike, upper involucral bracts awn-shaped, usually shorter than subtending spike, scabrous on veins and margins, not sheathed. Spikes 4-6, lowest one rather remote, others contiguous at top of culm; terminal spike male, sometimes with some female flowers at apex, narrowly cylindric, 2.5-3.5 cm, shortly pedunculate; lateral spikes female, cylindric, 1.5-4.5 cm, densely many flowered and slightly loosely flowered at base, lowest one rather long pedunculate, upper spikes shortly pedunculate. Female glumes brownish yellow or yellowish, ovate or oblong-ovate, ca. 2.5 mm, membranous, 1-veined, apex acuminate, mucronate. Utricles yellowish green, obliquely patent, more divergent at maturity, longer than glume, ovate or narrowly ovate, obscurely trigonous, 3.5-4 mm, membranous, shiny, glabrous, 5-veined abaxially, base subrounded, apex attenuate into a medium-sized to long and recurved beak, orifice emarginate. Nutlets brown, slightly loosely enveloped, obovate or subelliptic, trigonous, ca. 2 mm; style base slightly thickened; stigmas 3. Fl. and fr. Apr-Aug.

Streamsides, ditch sides, wet places in forests; 1100-1900 m. Hebei, Heilongjiang, Jilin, Liaoning, Shaanxi [Japan, Korea, Russia (Far East)].