Porter’s sedge

Cyperus refractus Engelmann ex Steudel var. lancastriensis (Porter) Kükenthal; Mariscus lancastriensis (Porter) C. B. Clarke

Herbs, perennial, cespitose, with inconspicuous, short rhizomes scarcely visible between culm bases. Culms basally cormlike, trigonous, (10–)20–80 cm × 1–3 mm, glabrous. Leaves inversely W-shaped, 20–70 cm × 5–11 mm, adaxial surface, margins minutely scabridulous. Inflorescences: spikes densely ellipsoid to obovoid, 2.5–4.3 × 1.5–3 cm; rays 5–10, 4–20 cm, glabrous; rachis 7–14 mm; bracts 3–8, horizontal to ascending at 45°, flat, 5–35 cm × 2.5–6 mm; rachilla persistent, wings 0.5 mm wide. Spikelets 50–90, linear-lanceoloid to linear-subulate, ± terete-quadrangular, (11–)12–13(–15) × 1.1–1.6 mm; distal spikelet spreading or ascending; floral scales persistent, 3–6(–8), appressed, whitish green or often yellow-tinted, sometimes reddish striate, laterally 4-ribbed, ovate-lanceolate, (3.9–)4.2–4.6(–4.8) × 1.6–2 mm. Flowers: anthers 0.7–1 mm; styles 1–1.5 mm; stigmas 2–3 mm. Achenes yellowish brown to brown, ± stipitate, conspicuously falcate, 3–4 times long as wide, oblong, 2.2–2.6 × 0.6–0.7 mm, apex obtuse, surfaces puncticulate.

Fruiting summer (Jul–Aug). Disturbed, sunny or partly shaded places in mesic or dry-mesic soils, often on riverbanks and flood plains; 0–800 m; Ala., Ark., Del., D.C., Fla., Ga., Ky., Md., Mo., N.J., N.C., Ohio, Pa., S.C., Tenn., Va., W.Va.