The southern border of the Amazon region presents a peculiar type of forest called Seasonal Evergreen Forest. Due to the lack of knowledge on this type of forest, the objective of this study was to develop a study on the phytosociological structure of rio das Pacas basin vegetation at Querência-MT. The vegetation sampling was composed of the distribution of 200 quadrant-points in which the four individuals closest to each point, with diameter > 10 cm were considered. The total density of the sampled area was of 761 ind./ha distributed into 53 species, 37 genera and 28 families. From species of high Importance Value, Ocotea leucoxylon, Myrcia multiflora, Pouteria gardneri, Sloanea eichleri, Miconia pyrifolia and Amaioua guianensis had ocurred in other Seazonal Perennial Forest areas, evidencing structural differences of this phytogeographic unit. The Shannon index (3.38) may be considered medium and the Pielou equability (0.85) indicates floristic heterogeneity of the arborous component.
Amazonian; diversity; Xingu