Phylogeny of the 'Eugenia' and 'Plinia'' groups
Phylogeny of South American genera with homogenous embryos – the ‘Eugenia’ and ‘Plinia’ groups.
Fiorella Mazine collecting Eugenia in the Atlantic Rainforest
Myrtaceae is the eighth largest dicot family in Brazil, often being one of the dominant woody families in the Mata Atlântica. Eugenia is the largest genus in neotropical Myrtaceae comprising c. 500 species in South America and occurring from Mexico and the Caribbean to Northern Argentina. Eugenia is well represented in Brazil by about 350 species, occurring mainly in forests but also found in campos rupestre, caatinga and cerrado vegetation. Eugenia was thought to belong to a subtribe (Eugeniinae) characterized by homogenous embryos with cotyledons swollen and often fused with an extremely reduced hypocotyl. This group is now known to be artificial with species falling in two unrelated clades, the informal ‘Plinia’ and ‘Eugenia’ groups.
This project, underway in collaboration with the Universities of São Paulo, ESALQ, São Carlos, São João del Rei and Minas Gerais (Brazil), seeks to publish a preliminary phylogenetic analysis of the ‘Plinia group’ and a more detailed phylogeny of South American Eugenia and associated genera (Calycorectes, Hexachlamys, Myrcianthes). This latter study seeks to establish the monophyly of Eugenia and its position relative to the other genera of the ‘Eugenia’ group, to test the monophyly of the eight sections of Eugenia as recognized by Otto Berg and to investigate relationships in sect. Racemosae Berg.
Results indicate that Eugenia is monophyletic and that there is some cohesion amongst the species of Otto Berg’s sections, in particular it appears that sect. Racemosae is monophyletic, supported by the morphological character of inflorescences exclusively in racemes. This represents the first steps in bringing an unwieldy and large genus under control and to a point where monophyletic sections can be monographed sequentially, likely beginning with sects. Racemosae and Phyllocalyx. Further phylogenetic work on confirmed monphyletic sections will likely begin with sect. Phyllocalyx. Results are in preparation for publication.
- Mazine, F. F. ; V. C. Souza (2009) . New species of Eugenia sect. Racemosae (Myrtaceae) from Brazilian Amazon Rainforest. Kew Bulletin, v. 64, p. 147-153.
- Mazine, F. F. ; V. C. Souza (2009) . New species of Eugenia sect. Racemosae (Myrtaceae) from Atlantic Forest, Eastern Brazil. Novon (Saint Louis), v. 19, p. 80-84.
- Lucas, E.J., Harris, S.A., Mazine, F.F., Belsham, S.R., Nic Lughadha, E.M., Telford, A., Gasson, P.E. & Chase, M.W. (2007). Suprageneric phylogenetics of Myrteae, the generically richest tribe in Myrtaceae (Myrtales). Taxon 56: 1105–1128.
Project partners and collaborators
University of São Paulo, Piracicaba campus, State of São Paulo
University of São Carlos, Sorocaba campus, State of São Paulo
University of Minas Gerais, Belo Horizonte, State of Minas Gerais
University of São João del Rei, State of Minas Gerais