Phaseolus leptophyllus G. Don (1832: 350) [clade A; sect. Revoluti Freytag].

TYPE: Sessé & Mociño s.n. (LECTOTYPE: OXF; ISOLECTOTYPES: F-846796, FI-4903 (in Herbarium Webbianum no. 51912), MA-601675, OXF, P-36706).

Its unique foliar morphology suggests we consider it as in a separate section (Freytag & Debouck 2002). Considering it close to P.acutifolius (Delgado-Salinas 1985) and next as a member of the Minkelersia (Delgado-Salinas et al. 2006) is a clear indication of the need for additional (and living) material. Some authors (Delgado-Salinas & Gama-López 2015; Acosta-DÍaz et al. 2019) have considered it as extinct. It is known only from the type collected in Guerrero in 1789.It is not mentioned in the list of “Vascular Plants of the Americas” (Tropicos 2020).