Gunnerais a genus of angiosperms with 30-40 species occurring in America, from Southern Patagonia to Mexico, in New Zealand, Tasmania, the Malayan Archipelago, Hawaii, from South Africa to Ethiopia and on Madagascar. Many studies have recently been conducted in order to identify the systematic position of Gunnera. In contrast, the phylogeny within Gunnerahas never been studied before. Consequently, no cladistic studies intended to explain the biogeographic antarctic pattern of Gunnerahave been presented so far. The phylogeny of Gunnerais investigated here for the first time by using three different gene regions, rbcL and the rps16 intron of the chloroplast genome, and the nuclear ribosomal transcribed internal spacer (ITS) region. Analyses based on single gene regions, as well as the combined analysis of the three gene regions, all confirmed the same general phylogenetic pattern: the rare G. herterifrom Uruguay, which is also the only annual in the genus, is sister to all other species. Furthermore, the African G. perpensais sister to two well-supported monophyletic clades, one including all the South American and the Hawaiian species, and the other comprising all the species from New Zealand, Tasmania and the Malayan area. The phylogeny of Gunnerais discussed and in the light of the new results, the evolution of some morphological characters, as well as biogeographical patterns of Gunneraare addressed.

Key words: biogeography, Gunnera, ITS, phylogeny, rbcL, rps16 intron