Family: Cyperaceae

Synonym: Cyperus panicoides Lam., Cyperus resinosus Hochst., Cyperus santonici Rottb.

Common name: Rice flatsedge

It is smooth, tufted, annual sedge that grows to 60 cm. The stem is sharply triangular. The root is yellowish red, fibrous. Leaves have sheaths enveloping the stem at the base, membranous, with blade linear, lanceolate, shorter than the flowering stem, about 5 mm wide. The inflorescence is a compound umbel, with primary rays about 10 cm long, secondary rays about 2 cm long, subtended by 3 to 5 (occasionally 7) bracts. The fruit has a yellowish brown achene, obovate, triangular in cross section, 1 to 1.5 mm long.

This weed is propagated by seeds, which may be dormant but can germinate about 75 days after shedding. It is a prolific seed producer and spreads quickly.

Cyperus iria grows well in moist to wet soil in annual and plantation crops. It is one of the most common weed in rice fields and other flooded crops. It is found nearly everywhere in irrigated rice fields.

Countries: Burundi, China, Costa Rica, Cuba, Egypt, Indonesia, Nepal, Nicaragua, Thailand, Venezuela, Vietnam

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