间穗薹草 jian sui tai cao

Rhizome slender and creeping. Culms loosely tufted, 15-25 cm tall, slender, trigonous above, clothed at base with pale brown bladeless sheaths. Leaves shorter than culm, blades linear, 1-2 mm wide, flat, margins scabrous. Involucral bracts glumelike. Inflorescence with upper 2 spikes approximate, lowermost 2 distant by at least 1 cm; spikes 3 or 4, gynaecandrous, ovate, 3-5 × 2-5 mm, few flowered. Female glumes pale, broadly ovate or ovate, ca. 2 mm, membranous, with green midrib. Utricles pale green-brown, longer than glume, oblong or ovate, plano-convex, 2.5-3 mm, subleathery, many veined on both faces, base rounded, spongy, shortly stipitate, apex nearly beakless, orifice entire or emarginate. Nutlets tightly enveloped, broadly elliptic, ca. 1.5 × 1.2 mm, subrounded at both ends; style base not thickened; stigmas 2. Fr. May. 2n = 54.

Forests. Heilongjiang [Japan, Kazakhstan, Korea, N Mongolia, Russia (Far East, Siberia); EC and N Europe, North America].