Cyperus schweinitzii Torr.

Cyperus schweinitzii is introduced, but not naturalized, in Massachusetts and Washington.

Herbs, perennial, rhizomatous. Culms trigonous, (10–)20–50 cm × (0.6–)1–2 mm, glabrous or more often scabridulous, either in distal 1/2 or over entire length; basal sheaths, 1–3, light brown, 1–4 cm, papery. Leaves flat to V-shaped, (2–)20–35 cm × 2–6 mm, margins and keel minutely scabridulous; proximal leaves bladeless. Inflorescences: spikes ± umbellate to slenderly (infrequently broadly) ovoid, 10–25 × 7–16 mm; rays 3–5, 1.5–8(–15) cm; bracts 3–7, erect (or declined at most 25–30° from vertical), (2.5–)8–20(–25) cm × (0.5–)1.5–6 mm; rachilla ± deciduous, wingless. Spikelets (1–)5–10(–20), oblong to linear-oblong, quadrangular, 7–10(–18) × (2.8–)3.2–4(–4.5) mm; floral scales deciduous, (1–)5–10(–14), spreading, laterally stramineous or dull whitish, sometimes also red-spotted, medially green, laterally 2–3-ribbed, medially 3-ribbed, broadly ovate to oblong-ovate, (2.3–)2.8–3.2 × (2–)2.4–3.2 mm, apex broadly rounded, often clear-erose, cusp 0.1–0.4 mm in proximal scales, 0.3–1 mm in distal scales. Flowers: anthers 0.8–1.4 mm; styles 0.1–0.3 mm; stigmas 1.5–3 mm. Achenes light to dark brown or nearly black, broadly ellipsoid, infrequently obovoid, 2–2.4 × 0.9–1.4 mm, base cuneate to ± stipelike, apex obtuse to broadly rounded, surfaces papillose. 2n = 166.

Alta., Man., Ont., Que., Sask.; Colo., Ill., Iowa, Ky., Mass., Mich., Minn., Mo., Mont., N.J., N.Mex., N.Y., Ohio, Okla., Pa., S.Dak., Tex., Utah, Wash., Wis., Wyo.; Mexico (Coahuila).

Fruiting late spring–early summer.

Riverbanks, sand bars, lakeshores, sand dunes, sandy openings in woods; 0–1000m.

Cyperus alterniflorus Schweinitz 1824, not R. Brown 1810

Cyperus schweinitzii is a species of sedge that is native to parts of North America.

Cyperus schweinitzii adalah spesies tumbuhan yang tergolong ke dalam famili Cyperaceae. Spesies ini juga merupakan bagian dari ordo Poales. Spesies Cyperus schweinitzii sendiri merupakan bagian dari genus Cyperus. Nama ilmiah dari spesies ini pertama kali diterbitkan oleh Torr..

Cyperus schweinitzii là loài thực vật có hoa trong họ Cói. Loài này được Torr. mô tả khoa học đầu tiên năm 1836.