Aristolochia gracilipedunculata, a new pseudostipule-bearing species from Bahía and Espíritu Santo (eastern Brazil), is here described and compared to other species present in this area that belong to the informal group Pseudostipulosae. The new species is easily recognizable by the presence of a long, filiform peduncle, and by the oblong, fimbriate perianth limb with a rounded and emarginate apex. Floral morphology of the new species is also compared to other non-Pseudostipulosae South American species with similar perianth shape.