Phaseolus microcarpus Martius (1829: 18) [clade A; not assigned to a sect.].

TYPE (lectotype):Plate 12 (the illustration of a plant raised from seed in a greenhouse at München,Germany) .

It seems that the original seed, obtained from Mr. FW Keerl, was collected near Tlalpujahua [Michoacán], Mexico. It is an annual vine from dry (warm) (sub-) and tropical deciduous forests, with a wide distribution from Durango, Mexico down to NW Costa Rica (Debouck et al. 2019), in the range 0–2000 m. It is an isolated species in the genus, with no clear link with any current section (Delgado-Salinas et al. 1999).

Specimens: MEXICO. Durango: S González 2185 (ENCB). Guanajuato: LI Aguilera 279 (CHAPA). Nayarit: O Téllez-Valdés 9344 (RSA-482469). Jalisco: R Ramírez-Delgadillo 2270 (IBUG-109694). Morelos: G Flores-Franco 305 (BM). Puebla: F Miranda 2312 (MEXU-74655). Michoacán: JN Labat 1201 (P). Guerrero: JC Soto-Núñez 5966 (MO-3851263). Oaxaca: E Domínguez-Licona 1897 (K). Chiapas: DE Breedlove 46145 (CAS-651680). HONDURAS. Francisco Morazán: JL Linares 6995 (MEXU-1161332). EL SALVADOR. La Unión: G Cerén 972 (LAGU-6096). NICARAGUA. Carazo: A Grijalva 4131 (MO-5149166). COSTA RICA. Guanacaste: B Hammel 24516 (INB-4136116).