Latin name

Cyperus imbricatus Retz.

Family

Cyperaceae

Common name(s)

Sedge

Synonym(s)

Cyperus radiatus Vahl, C. confertiflorus Schultes, C. densiflorus Link, C. spicatus J. Presl & C. Presl, C. mediorubescens Hayata, C. imbricatus var. capitatus (Boek.) Kük

Geographical distribution

Asia: China, Japan, and Korea.

South and Southeast Asia: Bangladesh, Cambodia, India, Indonesia, Lao PDR, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Sri Lanka, Thailand, and Vietnam.

Rest of the world: Argentina, Bolivia, Brazil, Colombia, Costa Rica, Dominican Republic, Ecuador, Guatemala, Honduras, Mexico, Nicaragua, Paraguay, Peru, Puerto Rico, Tanzania, Uruguay, Venezuela, West Africa.

Morphology

A rhizomatous perennial; up to 150—cm—tall.

Stem: smooth, slender to robust, tufted, 8—mm in diameter and 3—angled.

Leaf: pale green beneath, leathery, with lengthwise furrow: rough margins, leaf 3—12—mm—wide; sheath somewhat spongy and straw-colored to purplish black.

Inflorescence: compound umbel composed of digitately arranged, brown, 2—3—cm—long cylindrical spikes with numerous spikelets; spikelets 12—18 flowered and 4—9—mm—long.

Fruit: straw-colored nut, 0.6—0.8—mm—long.

Biology and ecology

Propagates by rhizomes and seeds; found in wetland rice and swamps.

Agricultural importance

Common and has caused significant yield losses in wet-seeded rice in Malaysia.

Management

Cultural control: thorough land preparation.

Chemical control: no information available.

Selected references

Hafliger E. 1982. Monocot weeds 3. Basle (Switzerland): CIBA-GEIGY Ltd. 132 p.

Kenji Noda, Teerawatsakul M, Prakongvongs C, Chaiwiratnukul L. 1985. Major weeds in Thailand. Bangkok (Thailand): Department of Agriculture. National Weed Science Research Institute Project. 142 p.

Kern JH. 1974. Cyperaceae. Flora Malesiana Ser. 1 7(3): 435-753.

Moody K. 1989. Weeds reported in rice in South and Southeast Asia. Manila (Philippines): International Rice Research Institute. 442 p.

Moody K, Munroe CE, Lubigan RT, Paller Jr. EC. 1984. Major weeds of the Philippines. College, Laguna (Philippines): Weed Science Society of the Philippines. University of the Philippines at Los Baños. 328 p.

Pancho JV, Obien SR. 1995. Manual of ricefield weeds in the Philippines. Muñoz, Nueva Ecija (Philippines): Philippine Rice Research Institute. 543 p.

Contributors

JLA Catindig, RT Lubigan, and DE Johnson