Rough Flat Sedge

For information concerning nomenclature of Cyperus retrofractus, see J. R. Carter and C. E. Jarvis (1986).

Herbs, perennial, cespitose. Culms with cormlike bases, sharply trigonous, 25–90 cm, glabrous proximally, minutely scabridulous distally. Leaves V-shaped, 14–40 cm × 3.5–8 mm, (pubescent on adaxial side of midrib). Inflorescences: spikes loose, obtrulloid to obdeltoid (broadest near apex, nearly as long as wide), 20–28(–34) × (12–)15–30 mm; rays 4–13, (1–)4–24 cm (longest ray shorter than bracts), glabrous; bracts 3–12, ascending at 30–45°, flat, 3–25 cm × 3–7 mm; rachilla persistent, wings 0.4–0.6 mm wide, covering 3/4 of mature achene. Spikelets 30–50, proximal one reflexed, distal ones divaricate, linear-lanceoloid, ± terete, (6.5–) 8–10(–17) × 0.5–0.7 mm; floral scales persistent, 3–6(–8), appressed, stramineous (suffused with reddish purple), 4–5-ribbed laterally, ovate-lanceolate, (4–)4.4–4.9(–5.4) × 1.3–1.5 mm; terminal scale not spinose, apex straight, excurved mucronate, or cuspidate. Flowers: anthers 0.7–1.2 mm; styles 1.5–2 mm; stigmas 2–2.5 mm. Achenes brown to brownish black, narrowly oblong, (2.2–)2.5–3 × 0.6–0.7 mm, base cuneate, apex obtuse, apiculate, surfaces puncticulate.

Ala., Ark., Del., D.C., Ga., Ky., Mo., N.J., N.C., Ohio, Pa., S.C., Tenn., Va.

Fruiting summer.

Roadsides, pastures, disturbed sites in sandy or clayey soils; 0–300m.

Scirpus retrofractus Linnaeus, Sp. Pl. 1: 50. 1753; Cyperus dipsaciformis Fernald; C. retrofractus var. dipsaciformis (Fernald) Kükenthal; Mariscus retrofractus (Linnaeus) Vahl

Cyperus retrofractus is a species of sedge that is native to eastern parts of the United States.