Cyperus retroflexus


Proc. Acad. Nat. Sci. Philadelphia. 14: 9. 1862.

Synonyms: Cyperus uniflorus var. floribundus Kükenthal Cyperus uniflorus var. retroflexus (Buckley) Kükenthal Mariscus uniflorus
Treatment appears in FNA Volume 23. Mentioned on page 186.

Herbs, perennial, cespitose, rhizomatous. Culms trigonous, basally tuberous-thickened, (5–)15–40(–80) cm × 1–2.5 mm, glabrous. Leaves flat to V-shaped, (5–)10–30(–60) cm × (0.5–)1–3(–4) mm. Inflorescences: spike 1, loosely to densely ovoid to cylindric, 8–36 × 8–20 mm; rays 3–6(–9), (5–)10–32 cm; bracts 3–6, horizontal to ascending at 30°, V-shaped, (1–)3–15(–30) cm × 0.5–4.5 mm; rachilla deciduous, wings 0.5–0.7 mm wide. Spikelets (5–)20–35(–65), linear to oblong (without narrowed basal portion), quadrangular; (2.2–)4–10(–18) × 0.7–1.1 mm; floral scales persistent, 1–5, appressed, pale greenish white laterally, stramineous with reddish dots, or deep red, greenish or light brown medially, 3–6-ribbed laterally, narrowly ovate to oblong-elliptic, 2.6–3.9 × 1.6–2 mm, apex rounded to ± acute, entire, mucronulate; distal scale with glabrous midrib and mucro 0.1–0.3(–0.5) mm; sterile terminal scale of spikelet only 0.4–0.6 mm wide, involute, frequently uncinate. Flowers: anthers (0.3–)0.4–0.6 mm; styles 0.4–0.5 mm; stigmas 0.5–0.9 mm. Achenes light brown to reddish brown, sessile or slightly stipitate, ellipsoid, (1.8–)2–2.4 × 0.6–0.8(–0.9) mm, apex slightly apiculate, surfaces puncticulate.

Phenology: Fruiting mid summer–early fall (Jul–Sep).
Habitat: Damp, disturbed soils, croplands
Elevation: 0–1000 m


V23 321-distribution-map.jpg

Ala., Ariz., Ark., Miss., Mo., N.Mex., Okla., Tex., Mexico.


Cyperus retroflexus is distinguished from other species of Cyperus with deciduous spikelets by the involute, sterile terminal scale of the spikelet. In plants with cuspidate scales, the terminal scale is usually somewhat recurved, giving the appearance of a hook at the end of the spikelet.

Selected References


Lower Taxa

... more about "Cyperus retroflexus"
Gordon C. Tucker* +, Brian G. Marcks* +  and J. Richard Carter * +
Buckley +
Ala. +, Ariz. +, Ark. +, Miss. +, Mo. +, N.Mex. +, Okla. +, Tex. +  and Mexico. +
0–1000 m +
Damp, disturbed soils, croplands +
Fruiting mid summer–early fall (Jul–Sep). +
Proc. Acad. Nat. Sci. Philadelphia. +
Illustrated +
Cyperus uniflorus var. floribundus +, Cyperus uniflorus var. retroflexus +  and Mariscus uniflorus +
Cyperus retroflexus +
Cyperus subg. Cyperus +
species +