Amaranth is of worldwide interest for its nutritional value as a vegetable and grain. The principal cultivated species used as grain are Amaranthus caudatus, A. cruentus and A. hypochondriacus. Two accepted hypotheses about the origin of A. cruentus consider A. hybridus as its ancestor. The objectives of this study are 1) to report the updated distribution and frequency of A. cruentus and A. hybridus in southeastern Mexico, Guatemala, and Honduras and 2) to assess their morphological diversity, using floral and fruit characters of both species in Mexico and Guatemala.