Abstract: The Atlantic Forest is one of the most threatened tropical forests in the world. Leguminosae, by its great richness and dominance among arboreal stratum elements, is of major importance in the floristic composition and structure of this forest. We investigated the distribution of legume species on an altitudinal gradient to find out the altitudinal zones with higher richness of species; the altitudinal zones with greater floristic similarity; the possible presence of species that may be exclusive to certain vegetation types and the altitudinal amplitudes of those species, as well as the occurrence of species substitution along the altitudinal gradient. Therefore, thirty one studies conducted in different altitudinal levels between 5° S and 29° S were analyzed. A matrix with 142 tree species distributed in altitudinal zones (every 100 m) from sea level to 2100 m was built. The greatest species richness was observed in the Submontane Forest (50–500 m) with 92 species. The cluster analysis revealed a strong dissimilarity of the 1400–2100 m (Upper Montane) and 0–10 m zones (Restinga Forest). The Submontane and the Montane Forest share the highest number of species (38 ssp.). Forty species are unique to Submontane. Substitution of species was verified. Some species have their preferred habitat located at a specific altitudinal amplitude, as is the case of Inga laurina and I. subnuda (0–10 m), I. lanceifolia and Machaerium scleroxylon (800–1200 m). The Leguminosae, although well adapted to the first colonization and establishment of diverse environment, was poorly represented above 1500 m altitude.

Key words: altitudinal gradient, Fabaceae, floristic similarity, Ombrophilous Dense Forest.