山丹薹草 shan dan tai cao

Rhizome short. Culms tufted, 25-40 cm tall, acutely trigonous, scabrous, clothed at base with blackish castaneous sheaths disintegrating into fibers. Leaves shorter than culms, blades linear, 2-3 mm wide, flat, margins scabrous. Involucral bracts setaceous, shorter than spike, sheathless. Spikes 4 or 5; terminal spike male, blackish brown, oblong, 1.5-1.8 cm, densely many flowered; lateral spikes female, oblong, 1-2 cm; lowest peduncle ca. 1 cm, upper spikes sessile. Female glumes blackish brown, oblong, ca. 3 × 1 mm, with light brown midrib, apex obtuse and rounded. Utricles light brown, longer than glume, plano-convex, 4-4.5 mm, base stipitate, apex abruptly contracted into a short beak, orifice truncate, entire. Nutlets loosely enveloped, oblong, base stipitate; stigmas 2. Fl. and fr. Aug-Sep.

● Riversides along valleys; ca. 3100 m. Gansu (Shandan).