Worldwide Distribution of Purple and Yellow Nutsedge (<i>Cyperus rotundus</i>and<i>C. esculentus</i>)

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 genus Cyperus . An additional 43% are in three other genera, Eleocharis , Scirpus , and Fimbristylis . The remaining 15% are found in six other genera, Scleria , Kyllinga , Rhynchospora , Bulbostylis , Fuira , and Dichromena . Purple nutsedge ( Cyperus rotundus L. # 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 esculentus L. # 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.