Cyperus congestus Vahl var. parishii (Britton ex Parish) Kükenthal

Herbs, annual, cespitose. Culms trigonous, 5–25 cm × 1–1.5 mm, glabrous. Inflorescences: spikes loosely ovoid, 15–25 mm wide; rays 1–6, 2–7 cm; bracts 2–5, 3–20 cm, ascending; rachilla deciduous, winged. Spikelets 5–30, linear, flattened, 6–22 × 1.5–2.2 mm; floral scales ± deciduous, (4–)8–12, red, reddish purple, or reddish brown, medially green, elliptic, laterally 2–4-ribbed, 2.3–3.1 × 1.2–2 mm, apex acute to obtuse. Flowers: anthers 0.3–0.4 mm; styles 1 mm; stigmas 1.3–1.6 mm. Achenes brown to dark purplish brown, broadly ellipsoid, 1–1.3 × 0.6–0.9 mm, surfaces puncticulate.

Fruiting summer. Stream banks, desert washes, arroyos, roadsides; 0 800 m; Ariz., Calif., N.Mex.