Phaseolus altimontanus Freytag & Debouck (2002: 183) [clade A; sect. Digitati Freytag].

TYPE: DG Debouck et al. 1525 (HOLOTYPE: US-3168865; ISOTYPES: BR, G, K, M, SI, UNL n.v., UC-1716192).

This reclining vine with light purple standard and white wings (Fig. 4) is considered as endemic because only a few populations are known to date, from pine-oak forests of Santiago and Cola de Caballo south of Monterrey in Nuevo León and neighboring Tamaulipas, Mexico, at 1500–1900 m (also noted by Acosta-Díaz et al. 2015). The species is considered threatened (Acosta-Díaz et al. 2019).

Specimens: MEXICO. Nuevo León: S Rodríguez-Tijerina 138 (ANSM-63277). Tamaulipas: J Hinton 24657 (ANSM-71567).