Molecular phylogenetic analysis of Eugenia L. (Myrtaceae), with emphasis on southern African taxa

With approximately 1000 species, Eugenia s.str. (excluding Syzygium) is one of the largest genera in the Myrtaceae. Morphological and anatomical studies concluded that two supraspecific groups (X and Y) exist in African members of Eugenia. A multigene approach was used to investigate phylogenetic/molecular relationships within southern African Eugenia, as well as representatives from elsewhere in the world. The cpDNA rpl16 intron data supported the distinctness of species groups X and Y. Little sequence divergence was found within the rpl16 intron of Eugenia. Nuclear sequence data were more variable than cpDNA and also supported the two groups. Combined data enhanced the resolution of closely related species. Species group X is related to Eugenia of the New World whereas the affinity of species group Y lies with Eugenia of the Old World. It is hypothesised that the origin of Eugenia in southern Africa is twofold. The presence of cryptic dioecy (structural androdioecy) in both groups of Eugenia in Africa is probably due to convergence. The suggestion that E. incerta is not native to Africa is supported by molecular evidence. The genus Monimiastrum is embedded within a clade with Mauritian Eugenia.We thank Danielle Florens, J. C. Sevathian and G. dArgent of the Mauritius Herbarium, Reduit, for the collection of all the material from Mauritius; Ed Biffin, CSIRO, Australia, for supplying DNA of E. reinwardtiana and Rhodamnia argentea; A. Salywon, Arizona State Univeristy, Tempe, USA for material from Florida; Timothy Lowrey, University of New Mexico, Albuquerque, USA, for material from Madagascar; and A. Urban, Stefan Neser (ARC, Pretoria) and J. H. Pedrosa-Macedo (Forest Research Foundation, Federal University of Parana, Curitiba, Brazil) for the material from Brazil. The authors are indebted to the National Research Foundation (South Africa) and the University of Pretoria for financial assistance.