Plants of the F2 and backcross generations derived from F1 hybrids between Papaver dubium L. (2n= 42) and P. lecoqii Lam. (2n= 28) were studied. It was deduced from the chromosome numbers of the F2 and backcross plants that the successful F1 gametes possess high chromosome numbers. This phenomenon is explained in terms of‘genomic buffering’, i.e. F1, gametes with large numbers of chromosomes are better buffered than those with small numbers of chromosomes to withstand the effects of a mixture of alien chromosome material resulting from meiosis in F1 hybrids between polyploids. The importance of this phenomenon is discussed in relation to the evolution of polyploid species of Papaver in Section Orthorhoeades.