The Guayana Highland has generated considerable interest among plant biologists because of their unique flora, high levels of endemism, and biogeographic isolation. The 10 genera of the tribe Mutisieae in this region are divided into two groups, one with actinomorphic florets occurring in Eastern Guayana Highland and the other with the bilabiate florets in Western Guayana Highland. The former is placed in the subtribe Gochnatiinae and the latter in the Mutisiinae. Despite their floral dimorphism and biogeographic distinctiveness, the Guayana Highland genera have been considered to be monophyletic by previous workers. Furthermore, this regional assemblage is considered to be a basal lineage in the subfamily Cichorioideae and the Mutisieae. We examined four genera of the Mutisieae from Guayana Highland using sequences of the chloroplast encoded ndhF gene. Phylogenetic analyses including previously published ndhF sequence from the Mutisieae and other lineages of Asteraceae suggested that the Mutisieae of the Guayana Highland are not monophyletic. Ths phylogeny also provides a framework for reevaluation generic relationships within the Mutisieae, phytogeography of the Asteraceae, and character evolution in the family.

Key words: Asteraceae, Guayana Highland, Mutisieae, Phylogeny