In the Brazilian semi-arid region, the flora in the sedimentary basins has been poorly studied, but the few surveys already done indicate great floristic and physiognomic heterogeneity. Even neighboring sites may be floristically different. To test this hypothesis, the floristic composition and the biological spectrum of the seasonal deciduous forest at Serra das Almas, Ceará, was analyzed and compared to those of 14 other northeastern Brazil sedimentary areas. A total of 104 species belonging to 40 families were found at the 1 ha site. Fabaceae, Euphorbiaceae, Erythroxylaceae and Myrtaceae were the families with the most species and phanerophytes the main life form, comprising 87% of the species. About 72% of the species were trees and shrubs, 15% were lianas, 6% understory shrubs and 7% herbs. A cluster analysis of the woody flora of the 14 areas, using the Jaccard index and a posteriori group averages, indicated the formation of groups as a function of geographical proximity of the areas. However, this effect was not significant, according to the Mantel test, demonstrating floristic heterogeneity even in neighboring areas. The flora of the forest at Serra das Almas was most similar to that of the vegetation found atop the Ibiapaba plateau.
dry forest; flora; plant life-form; semi-arid
