One mode of speciation that has been proposed for plants in general, and especially flowering plants, is diploid/diploid hybridization. This idea is in wide currency among plant evolutionary biologists although there a no unequivocal examples of this process and theoretically it seems highly unlikely. The PI proposes the test to chart the evolutionary genetics of three putative examples of this mode of speciation. In the process, he anticipates additional tests of the hypothesis that the three species are of hybrid origin. Subsequent events, such as chromosomal rearrangement, that might have had a bearing on the success of the hybrids and on isolation barriers will also be explored. Because hybridization has been assumed to be of widespread importance among the flowering plants, the results of this study could have a profound influence on our concepts of plant evolution.
