Phaseolus amblyosepalus (Piper) Morton (1944: 85) [clade A; sect. Minkelersia (Martens & Galeotti) Maréchal, Mascherpa, & Stainier]. TYPE: P Ibaña-García 456 (HOLOTYPE: US-1013387) .

The voucher 1013387 kept at US consists of two plants; the plant to the right is the type of P. amblyosepalus . This member of the Minkelersia can be easily identified by its large, rounded stipules. Its distribution seems to be the contact zone between Sinaloa and Durango in the Sierra Madre Occidental of Mexico, in pine forest at 2000–2700 m.

Specimens: MEXICO. Durango: Y Herrera 215 (ENCB), AC Sanders 21466 (UCR-105163), P Tenorio-Lezama 9685 (TEX-272982).