High genetic and morphological diversification of the <i>Euphorbia verrucosa</i> alliance (Euphorbiaceae) in the Balkan and Iberian peninsulas

We explored the diversification of southern European Euphorbia verrucosa alliance applying molecular (amplified fragment length polymorphism fingerprinting [AFLP], sequencing nuclear ribosomal internal transcribed spacer), karyological (relative genome size estimations, chromosome counts) and morphometric methods. The AFLP data inferred four main phylogenetic lineages corresponding to western-southern Balkan E. montenegrina, central serpentini, northern Balkan-central European-north Italian Iberian-southern French flavicoma. Genetic is strongest within Iberian peninsulas, suggesting Pleistocene persistence species in different micro-refugia. In contrast, weak genetic structure suggests Holocene (after last glacial maximum) expansion western Europe, likely from a refugium. Karyological provide evidence for tetraploidisation events flavicoma but not serpentini. By integrating with multivariate analyses, we propose new taxonomic treatment this group, mainly by recognising endemics montenegrina serpentini as independent redefining distributions verrucosa. Our study underlines importance peninsulas major refugia.