ABSTRACT
Of the great Brazilian biomes, the caatinga is one of the most poorly known from the floristic and phytogeografic point of view. In Piauí state, this biome covers about 37% of its territory, with only one conservation unit, the Serra da Capivara National Park. This work aims at listing the species collected in the Park area. With that objective, a survey was made of the material collected in the area deposited in the Herbarium "Graziela Barroso" of the Universidade Federal do Piauí - TEPBIUFPI, in adittion to samples resultant from collection in two geomorphologic units (sedimentary lands and crystalline soil) during a two year period. It was registered a total of 210 species distributed in 149 genus and 62 families. The families with greater diversity were Caesalpiniaceae, Fabaceae, Mimosaceae, Bignoniaceae, Euphorbiaceae and Myrtaceae totalling 46% of the species. It was verified that the heterogeneity of the physical environment influences in the distribution of species in the different biotypes of the area. As far as the semi-arid region as a whole is concerned, it was observed that, except for a small group of species, there is floristic similarity between the study area with other areas of caatinga in Brazil's Northeastern native semi-arid, whether installed in sedimentary lands or on crystalline soil.
Key-words:
Psemi-arid; caatinga; flora; Piauí state; Serra da Capivara