Adenocalymma includes approximately 76 species of lianas, shrubs and treelets, representing the largest genus from the Neotropical tribe Bignonieae (Bignoniaceae). As part of ongoing taxonomic studies within the “Adenocalymma-Neojobertia” clade, we found a new species endemic to the Brazilian Atlantic forest, Adenocalymma fistulosum. The new taxon resembles A. apetiolatum, A. sessile, A. subsessilifolium, and A. tephrinocalyx on the sessile leaf insertion and shrubby habit, but differs by the indument type, branch and branchlet pith, prophyll shape, inflorescence trichomes, bract and bracteole shape and size, corolla shape and color, presence of cupular trichomes in the corolla, and position of the anthers and stigma. The new taxon is described and illustrated. In addition, a distribution map, notes on the geographic distribution, habitat and morphological variation are provided.