Recent evidence supports the recognition of Gonolobus (Apocynaceae, Asclepiadoideae), a genus of 100–150 species of vines endemic to the NewWorld, as distinct from Matelea. Synapomorphies of Gonolobus s.l. include two indels in LEAFY, as well as winged follicles. Laminar dorsal anther appendages are exclusive to the Gonolobus s.l. clade, though lacking or reduced in some species. Given this evidence and in light of past controversies regarding circumscription, this study presents a synopsis of the three species of Gonolobus recognized in the United States and its territories: G. arizonicus, G. stephanotrichus, and G. suberosus. Lachnostoma arizonicum is lectotypified.