The vegetation in cangas (ironstone outcrops) houses dozens of rare species, several taxonomic novelties, and high alpha and beta diversity. Using a database consisting of 1080 angiosperm taxa, the vegetation associated with cangas in the Iron Quadrangle was characterized by its floristic elements, growth forms, and most frequent physiognomies. We analyzed the geographic distribution and the phytogeographic dominions of the 980 species. Also, in order to verify distinctions between canga vegetation in relation to five areas embedded in rupestral systems of Minas Gerais and Bahia, we analyzed the similarity of 920 angiosperm genera based in the species number. Compared to other rocky systems, especially those within the Espinhaço Range, canga vegetation is distinguished by the greater influence of floristic elements from the Atlantic dominion, greater frequency of arboreal and shrubby sinusiae, high abundance of genera like Solanum and Cattleya, and little physiognomic representation of some typically 'campos rupestres' genera. This distinction appears to be correlated with the geographic location of the Iron Quadrangle as well as the mineral and geomorphological characteristics of cangas.
rupestral systems; Espinhaço Range; metalophilous vegetation; ferruginous geosystem; ironstone outcrops
