This study described and compared the floristic similarity in four Deciduous Seasonal Forest fragments, and assessed the floristic relations between the tree (adult), the treelet and the sapling stratum. The fragments studied are distributed in Minas Gerais State and in Bahia State, Brazil. The vegetation sampling method followed the protocol of the "Rede de Parcelas Permanentes nos biomas Cerrado e Pantanal" for the tree, treelet and sapling strata. The floristic similarity between the fragments was obtained based on Jaccard and Czekanowski indices. Besides the similarity indices, Venn diagrams were drawn for the strata within each area. The four fragments and the three strata of each fragment presented low degrees of species sharing. The floristic differences among the strata may be due to environmental variations throughout time as well as the reproductive capacity of the species differentiated among the years. Besides the geographic distance (neutral theory), the environmental variations between the areas and the vegetation contacts (ecotones) with other biomes may have favored the occurrence of species adapted to the conditions of each fragment, which contributed to the distinct floristic composition.
floristic patterns; environmental heterogeneity; variation between strata
