Cyperus pygmaeus

Small, tufted, leafy annual with reddish roots. Culms triquetrous, smooth, 1–20 cm high, to 1.5 mm diam. Leaves not septate-nodulose, usually longer than culms, 1–2 mm wide. Inflorescence densely head-like, 6–18 mm diam.; involucral bracts leaf-like, 5–7 or more, spreading, very much longer than inflorescence, often a few smaller bracts protruding from the head. Spikelets flattened, very numerous per cluster, 3–5 mm long, 1.5–2 mm wide in side view, 8–20-flowered; rachilla not winged, persistent; glumes acute, short-mucronate, with sides 1–2-nerved, white to pale brown with conspicuous green keel, c.2 mm long, c. 0.5 mm wide; stamens 1 or 2; style 2(–3)-fid. Nut dorsally flattened with a flat or concave face against the rachilla, or sometimes trigonous, obovoid to ellipsoid, pale brown, from one-half to one-third as long as glume, 0.8–1 mm long, 0.2–0.5 mm diam. Flowers spring–summer.