The aim of this study was to analyze the floristic composition and structure of the tree layer of a forest fragment in the municipality of Luminárias, Minas Gerais State, southeastern Brazil. The forest fragment is locally known as Mata do Galego, has an area of c. 77 ha, and is located on the banks of the Ingaí River (21°29'S, 44°55'W). The flora was sampled out both in the stdy plots and in random collections throughout the fragment. Plant specimen vouchers are deposited in the ESAL Herbarium, Federal University of Lavras. The structural survey used a systematic design with 32 sample plots (20 × 20m) distributed on three transects which extended from the river margin to the forest edge. In these plots, all living trees, with circumference at breast height (cbh) ≥ 15.5 cm were recorded. Soil chemical and physical variables were obtained from the analysis of samples of the topsoil (0-20cm) taken at the center of each plot. The floristic survey totaled 201 species belonging to 129 genera and 57 families. The families with the highest number of species were Myrtaceae, Lauraceae, Fabaceae Faboideae, Rubiaceae, Euphorbiaceae, and Fabaceae Mimosoideae. The structural survey recorded 2343 individuals belonging to 159 species, 104 genera, and 50 families. The most abundant species were Casearia sylvestris, Lithraea molleoides, Machaerium stipitatum, Faramea cyanea, Diospyros inconstans, and Copaifera langsdorffii. The Mata do Galego had a relatively high species diversity (H' = 4.23 nat/indivíduo) and evenness (J' = 0.83) and may be related to the influence of adjacent vegetation formations and to the different microhabitats present within the forest, determined by several factors, such as canopy gaps, topography, variation in soil fertility and moisture.
flora; structure; semideciduous florest
