Molecular and morphological analyses of European Aconitum species (Ranunculaceae)

The systematics of the yellow-flowered Aconitum lycoctonum species complex (Ranunculaceae) has long been considered difficult because of high morpholo gical variability and hypothesized hybridization. To elucidate the systemat ic value of these taxa, and to study their phylogeny in a broader context, we studied all species of the subgenus Lycoctonum from Europe and the Cauca sus Mountains and the European species of the subgen. Aconitum. We sequence d the ITS region and the chloroplast intergenic spacer psbA-trnH and conduc ted parsimony analyses. We also measured morphological characters from 19 A . lycoctonum populations. The two subgenera in Europe are clearly separated but hybridization between subgenera might have taken place in the past. Se quence variation within A. lycoctonum and among all taxa of subgenus Lycoct onum was very low and probably the result of recent speciation, leading to one morphologically highly variable species in which color morphs could be seen as subspecies. There was high morphological variability within and amo ng populations and the morphological characters have no value as systematic characters.