Rhizomes short; shoots tufted; roots pale brown; scales brownish or reddish-purple, persistent. Stems (25-)30-55 cm, thick, rigid, trigonous, solid. Leaves 15-30 cm × 2-6 mm, ± flat or slightly keeled, abruptly tapered to a rough apex, mid green to deep blue-green; hypostomous; sheaths dark brown, often wine-red, persistent, with inner face hyaline (reflecting as silvery-green), persistent; apex straight; ligule 2-3 mm, obtuse to acute. Inflorescence 1/8 to 1/6 length of stem; bracts leaf-like, lower exceeding inflorescence, the lowest not or scarcely sheathing. Spikes 3-5, ovoid, 8-20 mm, clustered in an inclined head, becoming ± nodding in fruit, terminal spike female at top, male at base, lower female only; lower peduncles rough, as long as spike. Male glumes 4.5-6 mm, ovate-elliptic, red-black with pale midrib; apex acute or rounded. Female glumes 3.5-4.5 mm, ovate-elliptic, purple or reddish-black with pale midrib; apex ± acute. Utricles 3-4 mm, obovoid-ellipsoid, compressed at edges, green; beak 0.3-0.5 mm, slightly notched; stigmas 3; nut obovoid, trigonous.