ResumoApresenta-se um estudo taxonômico do clado Merianthera e das tribos Merianieae e Microlicieae (Melastomataceae) na Serra Negra, localizada no Complexo da Mantiqueira, região sul da Zona AbstractA taxonomic study of the clade Merianthera and the tribes Merianieae and Microliceae (Melastomataceae) of Serra Negra, located in the southern region of Zona da Mata of Minas Gerais, Brazil, is presented. The clade Merianthera is represented by Behuria parvifolia, Huberia nettoana and Cambessedesia hilariana, Merianieae is represented by Meriania claussenii, while Microlicieae is represented by Lavoisiera imbricata, Microlicia serpyllifolia, Rhynchanthera dichotoma, Trembleya elegans, Trembleya parviflora and Trembleya phlogiformis. The region is suffering environmental impacts due to Pinus and Eucalyptus planting, real-state speculation, disorganized visitation, illegal collection of plants, as well as the use of forest remnants and field areas for grazing. Regarding conservation, it should be highlighted the species B. parvifolia, H. nettoana and M. claussenii, probably threatened with extinction at regional or national levels. Identification keys, descriptions, illustrations, information on the geographical distribution and morphological comments for taxa of these groups in Serra Negra are presented.

This paper presents the first record of Pleroma boraceiense in Minas Gerais state, Brazil. This new occurrence is significant because the species had a restricted original distribution with about 10 gatherings in São Paulo State, in the Serra do Mar. On the other hand, a previous study showed a low floristic similarity between the Melastomataceae flora of the Serra do Mar State Park and that of Serra Negra region. In order to evaluate the environmental similarity, a predictive species distribution modelling has been developed. The gathering site in Minas Gerais (RPPN Mato Limpo) showed high suitability. It suggests the need for creation of protected areas in Serra Negra, since the region is suffering environmental impacts. Based on the recent phylogeny of the Melastomateae tribe and for the purpose of correct classification of the studied species, a new combination was made for Pleroma boraceiense.

Pleroma eglanduliferum, Justino & P.J.F. Guim. sp. nov. a new species of Melastomataceae (Melastomateae) from the Atlantic Forest of Minas Gerais State, Brazil, is described and illustrated, with their affinities and diagnostic characters discussed. Pleroma eglanduliferum is closely related to P. heteromallum (D. Don) D. Don and P. tedescoi Meirelles, L. Kollmann & R. Goldenb.) P.J.F . Guim. & Michelang. by plant architecture, with quadrangular branches and similar leaf in shape and indument. However, they can be distinguished by the variation in the stamens morphology and sizes of bracteoles. Pleroma eglanduliferum must be included in Critically Endangered category, since it is known only from one population, in a restricted area.