Coursetia caribaea var. trifoliolata 10.4 miles southwest of Zapotitlan on highway 125 between Huajuapan and Tehuacan, Puebla, Mexico. 8.0 miles northeast of the Oaxaca-Puebla border. On grayish sedimentary rock in the understory. Collected by Matt Lavin 5189 with Scott Sundberg on 7 October 1984 (specimen vouchers at MEXU and TEX Herbaria). Coordinates: 18.238011, -97.558824, 1900 m elevation. Coursetia caribaea var. trifoliolata is distinguished by long fusiform tuberous roots born from a woody caudex, tomentose stems where the purplish epidermis is visible through the trichomes, 3-5-foliolate leaves with adaxially impressed venation, and terminal leaflet only slightly larger than the lateral leaflets. Leaves with 3 leaflets at produced by populations at 1300-1400 m elevation and leaves with 5 leaflets produced by populations at 1500-2000 m elevation. This variety inhabit arid sites in open understory along the border of Puebla and Oaxaca, Mexico, including the Sierra de Zapotitlan and the Tehuacan Valley. iPhone photo of Kodachrome slide