GENETIC-VARIATION IN LATHYRUS-LATIFOLIUS (LEGUMINOSAE)

Lathyrus latifolius (everlasting pea) is a perennial vine native to Europe. Naturalized populations of L. latifolius occur in fields and on roadsides over large areas of the United States. Widely cultivated as a garden flower, L. latifolius produces abundant racemes of showy flowers that are bumblebee-pollinated. The seeds are heavy, large, and round, and exhibit no specialized means of dispersal. Allozyme diversity and population structure were determined for 32 populations of L. latifolius-30 from the southeastern United States and two from Oregon. Results from 21 allozyme loci indicate that genetic diversity is higher and population divergence is lower than expected based on the life history characteristics of the species. No association was found between genetic identity statistics and geographic distance between populations. Although the range in genetic diversity statistics among populations was unusually large, genetic drift did not appear to play a major role in structuring genetic variation. We conclude that the level of genetic diversity maintained within L. latifolius populations, and the level of population divergence found, is strongly influenced by its status as a cultivated garden flower and its human-associated mode of gene flow via seed dispersal.