This common weed of tropical agriculture has tuberiferous rhizomes, like its temperate relative, esculentus (FNA 23). These two taxa are part of a polyploid complex; 2n = 16-152+ (with 108 often predominant, at least in esculentus). C. rotundus has established locally in Paducah (MCRA), Louisville (JEFF) and Monticello (WAYN). Although not generally peristent in temperate regions, the population in Monticello began with a horticultural introduction in 1960-61 and was found in adjacent mowed lawns during 1995 (EKY). The tubers can be somewhat edible, but the plant has bitter aromatic chemistry of more medicinal than culinary interest.