Cyperus bipartitus
Ann. Lyceum Nat. Hist. New York 3: 257. 1836.
Herbs, annual, densely cespitose, with fibrous roots. Culms roundly trigonous, 3–25(–30) cm × 0.3–1.4 mm, glabrous. Leaves 1–3, V-shaped, 1–8 cm × 1–2 mm. Inflorescences: spike 1, loosely ovoid, compressed, 7–14 × 9–14 mm; rays 1–4, to 2(–3) cm; bracts 2–3, horizontal to ascending at 30(–45)°, V-shaped to flat, 1–12 cm × 0.5–1.5 mm. Spikelets 3–5(–8), flattened, oblong to oblong-lanceoloid, 8–18 × 2–2.6(–3) mm; floral scales (6–)10–26(–32), closely imbricate, laterally light to dark brown, medially light brown, laterally ribless, medially 2–3-ribbed, 2-keeled, oblong to ovate, 1.9–2.7 × 1.8–2.3 mm, apex obtuse. Flowers: stamens 2–3; anthers 0.4–0.5 mm, connective not prolonged; styles 0.6–1 mm; stigmas 1–1.5 mm. Achenes black, network of ridges forming isodiametric or square cells, sessile, obovoid to ovoid, 1–1.3(–1.5) × (0.6–)0.8 mm, apex apiculate, surfaces minutely punctate.
Phenology: Fruiting summer.
Habitat: Emergent shorelines, ditches, puddles, often in disturbed places
Elevation: 0–1500 m
Distribution
Ont., Que., Ala., Ariz., Ark., Calif., Colo., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., Nev., N.H., N.J., N.Mex., N.Y., N.C., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Mexico, Central America, South America.
Discussion
Selected References
None.