PHYLOGENY OF THE RANUNCULACEAE BASED ON EPIDERMAL MICROCHARACTERS AND MACROMORPHOLOGY

The epidermal microcharacters of 20 genera in the Ranunculaceae and 10 outgroup genera from the families Glaucidiaceae, Circaeasteraceae, Berberidaceae, Menispermaceae, and Lardizabalaceae were studied employing scanning electron and light microscopy. Characters such as type of trichome and stomatal length are valuable tools in assessing phylogeny in the Ranunculaceae. Using cladistic analyses, the basic division of the family into two major groups according to chromosome size (R- and T-types) was confirmed. By outgroup polarization, the T-type chromosome group is considered most primitive. Two major clades are recognized in the T-type taxa: the Aquilegia and Thalictrum group including closely related genera and a group consisting of Coptis and Xanthorhiza. Hydrastis is not considered a member of the Ranunculaceae. Further cladistic analyses of the R-type taxa using macrocharacters derived mainly from floral and fruit morphology resulted in the following subdivisions: the Anemone and Ranunculus group including Pulsatilla, Hepatica, and Clematis; the Cimicifuga and Actaea group and the Helleborus group including Eranthis, Trollius, and Caltha.