The aim of this work was to conduct a floristic and phytosociological survey on 11,034 hectares of the Extrema Lapinha Farm (13º46' to 14º S and 41º03' to 41º10' W), altitude from 295 to 380m, in the town of "Contendas do Sincorá", in Chapada Diamantina, Bahia State. The climate is of the BSwh' type, hot semi-arid, with an annual rainfall of 500-700mm, the rainy season being from November to January, with a mean temperature of 23ºC, and a relative humidity of 60-80%. The soils are podzolic red-yellow eutrophic and eutrophic litholic, with a lightly wavy relief. One hundred 20x5m plots were randomly distributed, where all plants with a diameter at breast height equal to or greater than 5cm were recorded. A total of 2,897 specimens was found, comprising 71 species, 51 genera and 23 botanic families with a 3.59% of them not identified. The families Euphorbiaceae (15.67%), Mimosaceae (13.80%), Bignoniaceae (12.35%), Caesalpiniaceae (7.14%), Boraginaceae (6.63%), Polygonaceae (6.63%), Anacardiaceae (6.04%), Burseraceae (4.93%), Apocynaceae (4.59%), and Combretaceae (4.28%) comprehended 82.09% of the surveyed specimens. The Cactaceae family represented 0.48% of the total number of this families, suggesting little evidence of a xerophylous characteristic in this caatinga site. The 10 most important species by the importance value index were: Commiphora leptophloeos (22.28), Croton zehntneri (19.39), Mimosa sp. (17.24), Tabebuia spongiosa (16.99), Myracrodruon urundeuva (15.38), Anadenanthera macrocarpa (14.25), Coccoloba termiflora (11.73), Caesalpinia sp. (11.17), Cordia sp. (10.79), and Tabebuia sp. (10.20).
plant sociology; vegetation; diversity