Cyperus gunnii subsp. gunnii

Tall, tufted perennial with short thick rhizome. Culms trigonous to terete, smooth or occasionally scabrous, to 150 cm high, 1.7–4 mm diam. Leaves septate-nodulose, as long as or exceeding culms, to 6.5 mm wide. Inflorescence simple to compound with 5–8 primary branches to 12 cm long; clusters dense, spicate to subdigitate, globose, to 2 cm diam.; involucral bracts leaf-like, 2 or 3 much longer than inflorescence. Spikelets flattened, numerous per cluster, 6–15 mm long, 1.5–2.5 mm wide in side view, 6–15-flowered; rachilla narrowly to broadly winged; glume spacing 1.2–2.2 mm; spikelet falling as unit, or rachilla persistent; glumes broad-acute with mucro to 0.2 mm long, with sides 2–4-nerved, usually red-brown to dark red-brown, 2–2.7 mm long; stamens 3; style 3-fid. Nut trigonous, narrow-ellipsoid, pale yellow-brown to dark brown, c. three-quarters as long as glume, 1.5–2.2 mm long, 0.3–0.7 mm diam. Flowers spring–summer.