Isozymes of Coreopsis Section Calliopsis (Compositae): Genetic Variation Within and Divergence Among the Species

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Abstract
Enzyme electrophoresis was employed to examine genetic variation within and among the three diploid (n=12) species comprisingCoreopsis sectionCalliopsis: C. leavenworthii, C. paludosa andC. tinctoria. Twelve enzymes specified by 20 genes were included, and those isozymes localized in the plastids were identified for several of the enzymes. Mean genetic identities calculated for pair-wise comparisons of 22 populations (four ofC. leavenworthii, one forC. paludosa, and 17 ofC. tinctoria) reveal no genetic differentiation betweenC. leavenworthii andC. tinctoria, whereasC. paludosa exhibits lowered values with the other two taxa. These results are in general agreement with concepts of relationships inferred from morphological and biosystematic data. That is,C. paludosa has been viewed as more distinct fromC. leavenworthii andC. tinctoria than the latter two are from each other. The high similarity betweenC. leavenworthii andC. tinctoria is somewhat unexpected, however, given the several morphological features that serve consistently to distinguish them.