A floristic survey was carried out in a semideciduous vegetation on São José plateau with the objective of amplifying the knowledge of its angiospermic flora and establishing its relationship with other vegetations types in the semi-arid region of Northeast Brazil. The flora was composed by 192 taxa belonging to 130 genera and 60 families. Euphorbiaceae, Caesalpiniaceae, Myrtaceae, Mimosaceae Fabaceae and Cactaceae were the families with the highest numbers of species. A cluster analysis indicated influence of the soil type in the distribution of species in the semi-arid region and separated a group of indicator species associated to sandy soils, composed of Caesalpinia microphylla Mart. (Caesalpiniaceae), Bocoa mollis (Benth.) R.S. Cowan (Fabaceae), Byrsonima gardneriana A. Juss. (Malpighiaceae) and Zanthoxylum stelligerum Turic. (Rutaceae). The flora of the area was related to that of the thorn (caatinga) and non thorn deciduous vegetation (carrasco) growing in areas with sandy soils. However, the high number of Myrtaceae species, unusual in caatinga, and the semideciduous character of the vegetation and presence of Cactaceae and Bromeliaceae suggest that the study area probably represents the end of a gradient that begins in sedimentary areas placed at smaller altitudes.
floristics; sedimentar plateau; semi-arid; Northeastern Brazil
