Eugenia is the largest neotropical genus in the Myrtaceae family. The genus has a wide geographical distribution, occurring from Mexico to Argentina. Eugenia species are rich in essential oils. Essential oils have applications in perfumery, cosmetics, food, pesticides and medicines. Several factors can influence the chemical composition and yield of essential oils, such as extraction technique, season of the year, genetic variations and environmental conditions. The understanding of how much each of these factors interferes in the formation of essential oils can contribute both to the development of more efficient production processes and to the ecological knowledge of the species of the genus. This study aimed to assess the influence of environmental variables on the chemical composition of essential oils from Eugenia species. The method used was to carry out chemometrics analyzes (regression analysis, factor analysis and multivariate analysis of variance) to explain the influence of environmental factors on the chemical composition of essential oils. The estimated regression model was significant (p-value < 0.05). Environmental variables analyzed significantly influenced and account for 11.5% of the variation observed in the chemical composition of essential oils. Phytochemical pattern of essential oil composition was also significantly different among Eugenia species.

Although biological surveys and taxonomic revisions provide key information to ecological and evolutionary studies, there is a clear lack of floristic and phytogeographic studies of the mountainous regions of Brazil, which harbor some of the most threatened plant ecosystems on the planet. Myrtaceae has been reported to be one of the most important families in the upland areas of Brazil, as well as in the Atlantic Forest Domain. In this study, we investigated the floristic composition of Myrtaceae throughout the Espinhaço Mountain Range and adjacent highlands of central-eastern Brazil, testing the following hypotheses: floristic similarity increases with geographic proximity; and species distribution is affected by geoclimatic variables. We performed statistical analyses using a database containing records of 199 species in 19 areas and of their respective geoclimatic variables. We also performed ordination analysis using non-metric multidimensional scaling (NMDS), the first and second axes of which explained 69% and 78% of the variation, respectively. The NMDS analysis demonstrated that variations in the Myrtaceae flora are highly sensitive to geoclimatic variables and geographic proximity. The NMDS ordination also showed a predominantly south-north gradient, as did the cluster analysis. This gradient was highly correlated with variations in rainfall and temperature, which are also associated with the three domains that coincide with the Espinhaço Mountain Range.

Apresentamos neste trabalho o estudo taxonômico das Myrtaceae ocorrentes no Parque Estadual do Itacolomi (PEIT), uma Unidade de Conservação localizada no estado de Minas Gerais, no sul da Cadeia do Espinhaço. A vegetação da área é formada por florestas montanas tropicais e campos rupestres. Para o tratamento taxonômico foram elaboradas descrições, comentários, chaves de identificação e ilustrações. Foram realizadas coletas de setembro 2009 a dezembro de 2010 e foram revisados os herbários BHCB, OUPR, RB e VIC. A família está representada no PEIT por 11 gêneros e 44 espécies: Blepharocalyx (1 sp.), Calyptranthes (1 sp.), Campomanesia (4 spp.), Eugenia (4 spp.), Marlierea (3 spp.), Myrceugenia (2 spp.), Myrcia (20 spp.), Myrciaria (1 sp.), Plinia (1 sp.), Psidium (3 spp.) e Siphoneugena (4 spp.).

This work aims identify and characterize species of Myrtaceae occurring in the Itacolomi State Park (PEIT), located in the state of Minas Gerais, in southern Espinhaço Range. The vegetation in the area comprises tropical montane forests and "campos rupestres". Descriptions, comments, identification keys and illustrations are presented. Collections were made in the PEIT from September 2009 to December 2010 and the BHCB, OUPR, RB and VIC herbaria were revised. The survey resulted in 44 species occurring in the PEIT, belonging to 11 genera: Blepharocalyx (1 sp.), Calyptranthes (1 sp.), Campomanesia (4 spp.), Eugenia (4 spp.), Marlierea (3 spp.), Myrceugenia (2 spp.), Myrcia (20 spp.), Myrciaria (1 spp.), Plinia (1 spp.), Psidium (3 spp.) and Siphoneugena (4 spp.).