Phylogenetic relationships of subtribe Ecliptinae (Asteraceae : Heliantheae) based on chloroplast DNA restriction site data

Phylogenetic analysis of chloroplast DNA restriction site data for 76 of th e 302 genera of Heliantheae sensu late using 16 restriction endonucleases r eveals that subtribe Ecliptinae is polyphyletic and that its genera are dis tributed in four different lineages. The ecliptinous genera Squamopappus, P odachaenium, Verbesina, and Tetrachyron (of the Neurolaeninae), along with other members of subtribe Neurolaeninae are the basal most clades of the pa leaceous Heliantheae. The mostly temperate species of subtribe Ecliptinae ( exemplified by Balsmorhiza, Borrichia. Chrysogonum, Engelmannia, Silphium, Vigethia, and Wyethia) are strongly nested in a clade with the Mesoamerican monotypic genus Rojasianthe as basal. The genera characterized by marcesce nt ray corollas traditionally classified in subtribe Zinniinae constitute a strongly supported group sister to Acmella, Spilanthes, and Salmea. The la rgest clade of ecliptinous genera is the most recently derived group within Heliantheae sampled. This large group of mostly Neotropical lowland genera (variously characterized by their winged cypselae, foliaceous phyllaries, and opposite phyllotaxy and exemplified by Perymenium. Wedelia, and Zexmeni a) has been and continues to be the most challenging group fi om a taxonomi c standpoint. The study provides new insights as to their relationships tha t will have a positive impact in future monographic studies of the group. T he genera of the Espeletiinae form a monophyletic clade and are sister to m embers of the Milleriinae and Melampodiinae. This result is consistent with their traditional taxonomic placement with genera such as Smallanthus with which they share a tendency for functionally staminate disc flowers. The p hylogenetically enigmatic genus Montanoa is sister to Melampodium. Members of subtribe Galinsoginae are clustered in two main lineages that correspond to the traditional division of the subtribe based on pappus characteristic s. There is no support For the monophyly of subtribe Galinsoginae, and the same results indicate some of its genera are paraphyletic.