Macrogeographic Allozyme Variation in Passiflora incarnata

Passiflora incarnata L. (Passifloraceae) is native to the southern United States and common in old fields and roadsides. This herbaceous, perennial vine has hermaphroditic flowers yet is self-incompatible. Large bees pollinate these flowers that produce fruits that may be eaten by mammals. Although the mode of sexual reproduction suggests the potential for long distance dispersal of genes, this species also displays extensive vegetative reproduction from rhizomes. Vegetative reproduction may reduce the amount of genetic variation within a population and increase differentiation among populations. We report on the macrogeographic allozymic variation within P. incarnata. Plants were collected from three regions in South Carolina (SC) and Georgia (GA). Genetic data were collected from nine polymorphic loci with starch gel electrophoresis of allozymes. In our sample of 168 plants from SC and GA, we observed 82 different multilocus genotypes. Plants with the same multilocus genotype were collected within and among regions. Genetic data indicated that there was little genetic differentiation among regions. These data suggest that there is extensive long distance transport of genes and that the species may rely heavily on sexual reproduction to establish new habitat.