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United States Department of Agriculture

Agricultural Research Service

Research Project: WEED BIOLOGY AND ECOLOGY, AND DEVELOPMENT OF SUSTAINABLE INTEGRATED WEED MANAGEMENT SYSTEMS FOR COTTON, SOYBEAN, CORN Title: Geographic range and morphological and chromosomal variability of Carex molestiformis (Cyperaceae) east of the Mississippi River

item Rothrock, Paul -
item Reznicek, Anton -
item Bryson, Charles

Submitted to: Castanea
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 12, 2011
Publication Date: August 1, 2011
Citation: Rothrock, P.E., Reznicek, A.A., Bryson, C.T. 2011. Geographic range and morphological and chromosomal variability of Carex molestiformis (Cyperaceae) east of the Mississippi River. Castanea. 76(2):178-182.

Interpretive Summary: Sedges include some of the world’s worst weeds. Many of these are non-native, however there are a few that are native to regions in the United States and have expanded their range, become weedy in agricultural areas, and are dispersed in contaminated hay, seed, and turf. Frightful sedge (Carex molestiformis) is a perennial native that has become weedy in pastures, hay meadows and along roadsides outside of its native range. This sedge continues to move eastward and northward in the US from the Ozark and Ouachita regions. Field surveys now place it in Georgia, Mississippi, and Ohio adding to recent reports of frightful in North Carolina, Virginia, and West Virginia. Additional research is needed to develop effective containment and control strategies to prevent frightful sedge from becoming weed problem.

Technical Abstract: Carex molestiformis (frightful sedge), described in 1997 as an endemic to the Ozark and Ouachita Mountain regions, is newly collected from Georgia, Mississippi, and Ohio. Herbarium records have also confirmed this species from North Carolina, Virginia, and West Virginia bringing the overall range of this species to 11 states. A morphological comparison of eastern with western populations of C. molestiformis reveal no regional differences, although eastern populations seem more ruderal than western. New chromosome counts for this species confirmed existing reports of n = 37 and also found agmatoploidy with n = 35.

Last Modified: 4/22/2015
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