Analyses of ploidy levels in progenies from 2x x 2x, 2x x 4x, 4x x 2x, 4x X 4x, and 4x x OP crosses during embryogenesis and seed germination indicate that the progenies include an array of aneuploids. The occurrence of some of the aneuploids was previously unreported. Most of the aneuploids were from 2x x 4x crosses, which yielded the largest number of progeny. Chromosome counts from embryos and endosperms of sectioned young seeds provide evidence that aneuploids originate in progenies of 2x x 4x crosses from the functioning of male gametes with more or fewer chromosomes than 2x = 18 in syngamy with reduced and unreduced female gametes. The origins of aneuploids in progenies from other crosses are problematical at this writing.