CRAWFORD, DANIEL J.*, REBECCA T. KIMBALL, and MESFIN TADESSE. Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, OH 43210. - Relationships in subtribe Coreopsidinae (Asteraceae: Heliantheae): insights from ITS sequences.
A molecular phylogenetic study of subtribe Coreopsidinae was conducted
using ITS sequences from 18 genera traditionally placed in the
subtribe. The two largest genera Bidens and Coreopsis do
not appear monophyletic, and occur instead in several strongly
supported lineages. The small genus Coreocarpus is resolved
into three distinct lineages. Although based on somewhat limited taxon
sampling, both Cosmos and Dahlia occur as monophyletic
groups, with Dahlia a basal lineage within the subtribe. The
ITS phylogeny does not support the inclusion of the two island genera
Petrobium and Oparanthus in Bidens, as has been
suggested. Strong support is provided for inclusion of the insular
genus Fitchia in Coreopsidinae, with Oparanthus
appearing sister to it. Prior investigations of the subtribe have
included grouping genera to reflect relationships and cladistic
analyses of morphological characters; certain results of the present
study are concordant with previous studies whereas in other instances
sharply different relationships are portrayed. The molecular phylogeny
resolves a number of strongly supported lineages within Coreopsidinae,
but there is not always clear resolution of relationships among the
lineages.
Key words: Coreopsidinae, ITS sequences, molecular phylogeny