Carex hermaphrodita Jacquin, Collectanea 4: 174. 1791; Mariscus hermaphroditus (Jacquin) C. B. Clarke; M. jacquinii Kunth

Herbs, perennial, rhizomatous. Culms trigonous, (10–)30–80(–140) cm × (0.4–)1–3(–5) mm, glabrous. Leaves V-shaped or flanged V-shaped, (5–)15–70(–90) cm × (2–)4–10(–13) mm, glabrous. Inflorescences: spikes 1(–5), rather densely ovoid or oblong-cylindric, (10–)25–45(–62) × 7–22 mm, 11–21 spikelets per 5 mm of rachis; rays (3–)5–10(–17), (1–)5–12(–24) cm; bracts (2–)4–8, ascending at 30–45°, V- or inversely W-shaped, (2–)8–40(–65) cm × (1–)2–8 mm; rachilla deciduous, wings 0.4–0.5 mm wide. Spikelets (10–)50–150, oblong to linear, quadrangular, (3–)4–8(–18) × (0.8–)1–1.2(–1.6) mm; distal spikelet spreading or ascending; floral scales (1–) 3–8, pale greenish white to golden brown, deep brown, or reddish brown, medially usually green, weakly to strongly 3(–4)-ribbed laterally, 1–3-ribbed medially, ovate to elliptic, (2–)2.6–3.2(–4) × 1.2–2 mm, apex obtuse. Flowers: anthers (0.4–)0.6–1 mm; styles 0.4–1.6 mm; stigmas 1–1.5 mm. Achenes brown or reddish brown, sessile or nearly so, ellipsoid, 1.4–1.8(–2) × 0.6–0.8(–1) mm, apex acute to obtuse, slightly apiculate, surfaces puncticulate.

Fruiting summer–fall. Arroyos; 500–1200 m; Ariz., Tex.; Mexico; West Indies; South America.

An erroneous report of Cyperus hermaphroditus from Alabama was based on misidentification of C. thyrsiflorus.