In order to determine their taxonomic significance, 10 pericarp structure characters were scored for 21 Amaranthus L. taxa. In many, pericarp patterns permit recognition of the taxa as species. Differences between cultivated taxa and their wild relatives offer new arguments against their taxonomic union. The relationships between other closely related taxa are also analyzed (A. quitensis and A. hybridus: A. bouchonii and A. powellii; A. hybridus and A. powellii; A. blitum and A. emarginatus). Mechanisms of dehiscence and terminology for the fruit of Amaranthus are considered
