The mode of origin of the hexaploid (6x=48) European plum Prunus domestica has been re-examined. It is argued that the evidence in support of an allo-polyploid origin and the participation of 4x P. spinosa in the formation of this fruit tree is far from being satisfactory. Instead, the morphological affinities between P. domestica, P. spinosa and P. cerasifera (= P. divaricata) and the available cytogenetic evidence seem to implicate 2x, 4x, 6x P. cerasifera as the sole wild stock from which the cultivated 6x European plum could have evolved.