Allozyme Divergence and Intraspecific Variation in Coreopsis grandiflora (Compositae)

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Abstract
Coreopsis grandiflora is an herbaceous perennial occurring primarily in the southeastern United States. It is morphologically variable and the variation is accommodated in three diploid (var. grandiflora, var. harveyana, var. saxicola) and one hexaploid (var. longipes) varieties. Populations of the three diploid varieties are usually highly interfertile. An electrophoretic study of 14 soluble enzymes presumably coded by 26 genes revealed no differentiation between any of the varieties. Comparable levels of genetic variation were found in populations of each variety and within each variety as a whole. The high genetic identity between the hexaploid var. longipes and the three diploid varieties suggests that the former is an autopolyploid in the sense that its origin lies exclusively within C. grandiflora. All alleles detected in the hexaploid were also found in the diploids, and no fixed heterozygosity was found at any gene in any population of var. longipes. The electrophoretic evidence is concordant with the high morphological similarity between var. longipes and diploid varieties of C. grandiflora in suggesting an autoploid origin for the former.