Herbs, perennial, stoloniferous; stolons soft, spongy, flexible when dried, 2-8(-15) cm, bearing tubers (3-)6-11 mm diam. Culms trigonous, 15-60 (-100) cm × 0.6-3.4 mm, glabrous. Leaves 3-7, flat to V-shaped or flanged V-shaped, (6-)20-40(-80) cm × 2-4 (-6.5) mm. Inflorescences: spikes broadly ellipsoid to ovoid or hemispheric, (12-)18-30 × (12-)18-35 mm; rachis 4-17 mm; rays 4-10, (0.3-)2-12 cm; bracts (3-)4-5(-7), ± horizontal to ascending at 45(-75)°, V-shaped to flanged V-shaped, (1.5-)5-30 cm × 0.5-4 mm; rachilla persistent, wings hyaline, 0.3-0.5 mm wide. Spikelets (3-)10-20(-28), divaricate or ascending, yellowish brown to dark brown, linear to linear-lanceoloid, compressed-quadrangular, (5-)10-20(-55) × (1.2-)1.4-2(-3) mm; floral scales persistent, 6-34, spreading or appressed, ovate-lanceolate, laterally 7-9-ribbed, laterally yellowish brown to dark brown medially brownish, reddish, or greenish, ovate, or ovate-deltate, medially 3-ribbed, 1.8-2.7(-3.4) × (1-)1.5-1.8(-2.4) mm, apex acute or sub-acute. Flowers: anthers (1-)1.2-1.5(-2.1) mm; styles (0.7-)1-1.2(-2.2) mm; stigmas (1.2-)1.8-2.3(-4) mm. Achenes (seldom maturing) brown, sessile, ellipsoid, (1.1-)1.3-1.5(-1.6) × 0.3-0.6(-0.8) mm, apex obtuse, surfaces puncticulate. Cyperus esculentus is a widespread and polymorphic species. Although seven varieties have been recognized (G. Kükenthal (1935-1936), recent studies based primarily on spikelet features provided support for four varieties (P. Schippers et al. 1995). Cyperus esculentus var. esculentus is restricted to the Old World.
Sweet-scented perennial with numerous slender rhizomes ending in small tubers; stems stout, triquetrous, 1-7 dm, smooth; lvs basally disposed, elongate, 3-8 mm wide; at least the lower invol bracts surpassing the infl; rays usually several, to 7 cm but more often not surpassing the sessile spikes, often again branched at the top; prophyll obliquely truncate or prolonged 1-3 mm beyond the orifice; spikes numerous in short-cylindric spikes, slender, 0.5-5 cm, only 1-2 mm wide, with 8-30+ fls; scales yellow-brown, (2-)2.5-3(-3.5) mm, thin, scarcely keeled, ovate, acute, conspicuously 7-9-nerved; rachilla persistent, narrowly hyaline-winged; achenes oblong, unequally
trigonous, 1.3-2 mm, tan to golden-brown; 2n=108. Damp or wet soil, sometimes a weed; widespread in trop. and temp. (but not cold-temp.) regions, and nearly throughout our range.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.