CHROMATOGRAPHIC EVIDENCE OF HYBRIDIZATION AND EVOLUTION IN PHLOX MACULATA

Representatives of P. maculata ssp. maculata and P. glaberrima ssp. interior and 36 putative hybrids were collected from a population in central Indiana. Chromatographic analysis revealed the presence of nine diagnostic components in P. maculata ssp. maculata and eight such components in P. glaberrima ssp. interior. Putative F₁ hybrids contained all or most of the parental marker components; markers of the non-recurrent parent were absent in the two classes of putative backcross progeny. The characters of P. maculata ssp. pyramidalis are a composite of those present in P. maculata ssp. maculata and P. glaberrima ssp. interior, and the former is virtually identical to certain hybrids from the population in question. The contention that P. maculata ssp. pyramidalis is a stabilized derivative of natural hybridization between these taxa is substantiated by the presence of all of the diagnostic constituents of the putative parents on its chromatograms. It is the author's opinion that the definitive data which chromatography affords will be invaluable in elucidating the complex pathways of evolution in Phlox.