Attempts to trace the origin of organisms on islands is frustrated by the major morphological changes that often occur following long distance dispersal and speciation. The Canary Islands exemplify how island environments influence speciation. The unique flora of the Canary Islands includes approximatedly 600 endemic species with at least 23 endemic genera that represent 40% of the native plant species of these islands. A molecular phylogenetic study based on chloroplast and nuclear DNA regions suggest that the ancestor of the Macaronesian endemic genus Bystropogon (Lamiaceae) arrived from the New World. These results provide further molecular evidence for a floristic link between the Macaronesian Islands and the New World previously shown in Sedum (Crassulaceae) and Pericallis (Asteraceae). Our results also provide an initial phylogeny within the Mentheae tribe and will help to resolve the intergeneric relationships and evolutionary history of this tribe.

Key words: ITS, long-distance dispersal, oceanic islands, phylogeny, trnl/f