Vascular flora of semi-arid region, S o José do Piauí, state of Piauí, Brazil

The Caatinga biome is located in the semi-arid region of northeastern Brazil and covers about 37 % of Piauístate. The main objective of the present study was a characterization of the Caatinga flora of the farm of Morro do Baixio,in state of Piauí, Brazil (06°51’13” S; 41°28’15” W, at 400 to 540 m above sea level) in view of the fact that very few suchsurveys were conducted in the state. The flora of the farm was surveyed monthly, during a year, to gather herbs, epiphytes,parasites, sub shrubs, shrubs and trees. We encountered 136 species belonging to 46 families, including a new species ofBauhinia. The richest families were Caesalpiniaceae (15 spp.), Fabaceae (11 spp.), Bignoniaceae and Mimosaceae (both withnine spp.). We observed a higher frequency of typical species from sedimentary Caatinga. However, local conditions favorthe appearance of species that occur in Carrasco and Cerrado.