Cyperus iria L.
Family: Cyperaceae
(en: ricefield flatsedge)
Cyperus iria image
Sue Carnahan  
Herbs, annual, cespitose. Culms trigonous, (5-)20-60 cm × (0.2-) 0.6-2.4 mm, glabrous. Leaves (1-)3-4, V-shaped, 15-40 cm × 3-6 mm. Inflorescences: spikes 2-5(-8), oblong to ovoid, 2-10 cm × 3-12 mm; rays 4-8, to 11 cm; bracts (4-)5(-7), ascending at 45°, V-shaped, (1.5-)8-30(-50) cm × 1-6 mm; rachilla persistent, wingless (successive floral scales 0.7-0.9 mm apart). Spikelets 10-30, compressed, linear to ellipsoid, 4-20 × 1.5-2.1 mm; floral scales deciduous, (2-)6-26, laterally brown to golden brown, edges clear, medially green, 5-ribbed, outermost ribs more noticeable than others, obovate to nearly orbiculate, 1.3-1.8 × 1.2-1.8 mm, margins emarginate, apex with mucro 0.05-0.12 mm. Flowers: stamens 2(-3); anthers (0.2-)0.3-0.4 mm, connective tips reddish, less than 0.1 mm; styles less than 0.1 mm; stigmas 0.2-0.4 mm. Achenes brown, slightly stipitate, obovoid, 1.2-1.4 × 0.5-0.7 mm, apex apiculate, surfaces puncticulate. Fruiting summer-fall (Jul-Oct). Damp to moderately dry, disturbed soils; 0-500 m; introduced; Ala., Ark., Calif., Conn., Fla., Ga., Ill., La., Md., Miss., Mo., N.Y., N.C., Okla., S.C., Tenn., Tex., Va., W.Va.; Mexico; Central America; South America; Asia; Africa; Australia. Cyperus iria was first recorded in the New World from the southeastern United States in the 1840s.

Tufted annual to 6 dm, with rather short, basally disposed lvs; rays usually well developed and commonly branched at the top; spikes loose and open, 1-2 cm, bearing several rather distant, ascending spikelets; spikelets 10-20-fld, to 1 cm; rachilla persistent; scales broadly obovate, rounded-emarginate, scarcely mucronate, 1.2-1.7 mm, with green midrib and golden-brown sides; rachilla wingless; stamens 2 or 3; achenes trigonous, 1-1.5 mm, blackish. Swamps and muddy ground; native of Eurasia, intr. in se. U.S. as far n. as s. Ill., Ky. and se. Va.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.
Cyperus iria image
Sue Carnahan  
Cyperus iria image
Sue Carnahan  
Cyperus iria image
Sue Carnahan  
Cyperus iria image
Sue Carnahan  
Cyperus iria image
Gordon Tucker  
Cyperus iria image
Cyperus iria image
Sue Carnahan  
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image
Cyperus iria image