The Genetic Mosaic ofIrisSeriesHexagonaein Florida: Inferences on the Holocene History of the Louisiana Irises and Anthropogenic Effects on Their Distribution

Iris series Hexagonae is a small, monophyletic complex of five species and associated hybrid populations, popularly known as the “Louisiana irises.” The Hexagonae alliance of Iris has been recognized as a textbook case of introgressive hybridization on the basis of numerous studies in Louisiana. In light of field observations of phenotypic heterogeneity among Florida populations, we investigated genetic variation within and among 37 populations of Iris series Hexagonae from Florida, seven from Louisiana, and one from Texas with 19 microsatellite loci. We wished to test the hypothesis that the Lake Wales Ridge and Polk Uplands of Florida, which remained above sea level maxima during the early Pleistocene, might be the sites of origin for all extant iris populations in Florida and possibly the series Hexagonae in its entirety. We also hypothesized that phenotypic heterogeneity observed in Florida iris would be reflected in patterns of allelic diversity. Finally, we wished to seek evidence of Native American...