The Southwestern region of Paraná State is an area of great ecological relevance because it represents an ecotone between two important forest types of the Brazilian south-southeastern region: the Seasonal Semideciduous Forest (SSF) and the Araucaria Forest (AF). Despite its importance, there is a lack of floristic surveys and vegetation studies in this region. In this study, we assessed floristic and structural attributes of the vegetation at three different native forest sites, located in Quedas do Iguaçu, Paraná State. Moreover, we made a phytogeografical characterization of the studied forests, based on the data we collected, and on the list of species surveyed in other 52 studies in SSF and AF of Brazil. Samples were taken using the point-centered-quarter method. All individuals with diameter at breast height > 5 cm were identified to the species level. Together, 128 species were found. Within sites, the number of species varied from 63 to 78. The three areas are distinguished with respect to structure and most abundant species. In addition, the areas differed with respect to the degree of influence of SSF and AF on their floristic composition. Comparatively, the lower altitude area, located in Iguaçu River's valley, has more elements of SSF on its floristic composition, while the other two areas, located in higher altitude areas, are more influenced by AF, with Araucaria angustifolia (Bertol.) Kuntze on their list of species.
Seasonally Dry Forest; Araucaria Forest; flora; phytogeography; Atlantic Forest
