The remarkable diversity of Eupatorieae in the Brazilian flora has received little study, despite the tribe's very high levels of endemism and importance in the threatened Cerrado and the Atlantic Forest biodiversity hotspots. Eupatorieae are one of the largest tribes in Asteraceae with 14 of 19 recognized subtribes occurring in Brazil. We constructed the largest phylogeny of Brazilian Eupatorieae to date that sampled the nrITS and ETS, chloroplast ndhI and ndhF genes, and the ndhI-ndhG intergenic spacer for 183 species representing 77 of the 85 Brazilian genera of the tribe. Maximum likelihood and Bayesian phylogenetic analyses showed that these species are not collectively monophyletic, so their distribution reflects multiple introductions into Brazil. A novel clade was found that includes 75% of the genera endemic to Brazil (Cerrado-Atlantic Forest Eupatorieae, "CAFE" clade). This radiation of at least 247 species concentrated in the Cerrado and Atlantic Forest biomes of central eastern Brazil is <7 my old and exhibits several ecologically diverse life forms. Eight subtribes of Brazilian Eupatorieae (Ageratinae, Alomiinae, Ayapaninae, Critoniinae, Disynaphiinae, Eupatoriinae, Gyptidinae and Hebecliniinae) and 16 genera (Ageratum, Agrianthus, Austroeupatorium, Bejaranoa, Chromolaena, Critonia, Disynaphia, Grazielia, Hatschbachiella, Heterocondylus, Koanophyllon, Lasiolaena, Neocabreria, Praxelis, Stylotrichium, and Symphyopappus) were found to be polyphyletic. We attribute incongruities between the molecular phylogenetic results and the current classification of the tribe mostly to convergent evolution of morphological characters traditionally used in the classification of the tribe. We used these phylogenetic results to suggest changes to the classification of some subtribes and genera of Eupatorieae that occur in Brazil.
Keywords: Campos rupestres; Cerrado; Endemism; Eupatorieae; Parallel evolution; Radiation.
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