A survey of the flora was carried out on deciduous shrubby vegetation from the sedimentary plateaus of Ibimirim, Pernambuco State, Brazil. In 343 collections, 139 taxa were identified, these being distributed in 92 genera and 38 families. The families richest in species were: Euphorbiaceae, Fabaceae, Caesalpiniaceae and Mimosaceae, with 42% and 33% of the species and genera, respectively. Data analysis of 831 species listed in 15 floristic surveys from 19 sites (Ceará, Pernambuco, Piauí and Sergipe States) showed that the area studied has the most species in common with sites located on sedimentary plateaus and caatingas that overlie cristaline rock, and the fewest in common with the cerrado vegetation of Piauí State. The vegetation is classified as caatinga based on the flora, functional aspects and degree of water deficiency.
caatinga; Angiosperm flora; semi-arid region