Abstract
Erythroxylum riparium, a new species of Erythroxylaceae from the Brazilian Atlantic Forest, is described and illustrated. The species was found in southern Bahia State growing along river banks within tropical rain forest fragments. It can be distinguished from other similar species of Erythroxylum by the combination of branchlets intensely dotted with elliptic lenticels, these often united with each other, undulate leaf margin, three bracteoles per flower, and partially connate styles. These diagnostic characters and other observations concerning the new species are presented and compared with those from similar species.