New Chart Could Put the Squeeze on Sedges

A new chart for identifying and distinguishing among 27 sedge species that are weeds of U.S. crops will help farmers whack these pests.

Sedges are grass-like plants in the genus Cyperus. Some Cyperus sedges are useful, the most famous being C. papyrus, from which ancient Egyptians made paper.

But plenty of sedges are weeds that crowd out crops around the world. They cause problems in agriculture, forestry and urban and rural areas. Worldwide, they cost billions of dollars a year in crop competitionand control measures.

Botanically, where there’s sedge, there’s often confusion. So, to help U.S. farmers accurately identify the sedge weeds in a given field, botanist Charles T. Bryson developed a reader-friendly table in cooperation with scientists in Arkansas and Florida. In Stoneville, Miss., Bryson works at the Southern Weed Science Laboratory of the Agricultural Research Service. ARS is the U.S. Department of Agriculture’s chief scientific research agency.

The genus Cyperus contains about 600 sedge species. But many are often misidentified as other weeds in the Cyperaceae family. The family includes sedges and much more: over 4,000 species in 90 to 115 genera.

Currently, no single text of publication in the United States treats all the species in the new chart—14 native and 13 exotic (non-native) Cyperus sedge weed species in the U.S. Among them is purple nutsedge, considered the world’s worst weed. The chart also contains information on yellow nutsedge, rice flatsedge and small flower umbrella sedge, all among the world’s 34 worst weeds.

Nomenclature, common names, distribution, ecology, biology and habitat data are presented for each species. Reprints including the genera key and tables on native and non-native Cyperus are available from Bryson.

Scientific contact: Charles T. Bryson, ARS Southern Weed Science Laboratory, P.O. Box 350, Stoneville, MS 38776, phone (601) 686-5259, fax (601) 686-5422, cbryson@ag.gov.