Worldwide Distribution of Purple and Yellow Nutsedge (Cyperus rotundusandC. esculentus)

Abstract

The family Cyperaceae includes approximately 3000 species, of which about 220 species are identified as weeds (Table 1). Nearly 42% of these weeds are in the genusCyperus. An additional 43% are in three other genera,Eleocharis,Scirpus, andFimbristylis. The remaining 15% are found in six other genera,Scleria,Kyllinga,Rhynchospora,Bulbostylis,Fuira, andDichromena. Purple nutsedge (Cyperus rotundusL. # CYPRO) was identified as the world's worst weed based on the number of countries where it was reported as a serious, principal, or common weed. Competition with crops was the major factor in determining weediness. From the same report, yellow nutsedge (Cyperus esculentusL. # CYPES) ranked sixteenth. This contrasts with relative rankings of these two species in the United States where yellow nutsedge is more widespread than purple nutsedge.