in J. Lamarck and J. Poiret, Tabl. Encycl. 1: 147. 1791.
Herbs, perennial, cespitose, rhizomatous. Culms trigonous to terete, 20–100 cm × 2–6 mm, soft (flattened in drying), glabrous, often flopping over and rooting at base of rays. Leaves: blades reduced to sheath. Inflorescences: rays 100–250, 5–16 cm; 2d order rays 0.5–5 cm; bracts 2–3, horizontal or reflexed, 4–12 cm × 1.5–4 mm. Spikelets 1–30, linear-lanceoloid, ellipsoid to narrowly ovoid, compressed-quadrangular, 6–17 × 1–1.5 mm; floral scales 5–12, reddish brown, 1–3-ribbed, 1.2–1.7 × 0.7–0.9 mm, apex mucronulate. Flowers: stamens 3; anthers 1–1.2 mm; styles 0.3 mm; stigmas 1–1.3 mm. Achenes brown, obovoid, 0.4 × 0.2 mm, base stipelike to nearly cuneate, apex obtuse, surfaces finely reticulate.
Phenology: Fruiting summer.
Habitat: Pond shores, marshes
Elevation: 0–200 m
Introduced; Calif., Fla., tropical e Africa.
Cyperus prolifer has long been cultivated in fish ponds and water gardens and has been reported under the name C. isocladus.