紫疣薹草 zi you tai cao

Rhizome short, oblique, indurate. Culms tufted, 12-55 cm tall, trigonous, scabrous above, clothed at base with dark brown sheaths disintegrating into fibers. Leaves shorter or longer than culms, blades linear, 1.5-2.5 mm wide, flat, margins scabrous, apex long acuminate. Lower involucral bracts setaceous, upper glumelike. Spicate inflorescence long cylindric, 3-6.5 × 5-10 mm; spikes numerous, androgynous, ovate, 5-7 mm. Female glumes yellowish brown, ovate, 2.2-3 × 1.5-2 mm, membranous, green 3-veined at middle. Utricles yellowish brown, slightly longer than glume, ovate-conic, plano-convex, 2.5-3.2 mm, subleathery, many veined on both faces, with several purple-red tubercles abaxially, base subrounded, spongy, shortly stipitate, margins from middle to apex with narrow denticulate wings, apex gradually narrowed into a beak, orifice 2-toothed. Nutlets loosely enveloped, ovate or subelliptic, biconvex, 1-1.2 × ca. 1 mm wide, lustrous, base shortly stipitate; stigmas 2. Fl. and fr. Jun-Sep.

Wet places on slopes or grasslands. Jiangsu, Jiangxi [Japan, Korea].