Areoles nearly circular, 2 × 2 mm; spines radially spreading. Flowers 22-25 × 7-8 cm. Flowering spring-summer; fruiting summer-early fall. Sonoran Desert, sandy or gravelly loams, creosote bush-bursage flats, edges of washes and on slopes of small hills; 300-1100 m; Ariz.; Mexico (Sonora). Peniocereus greggii var. transmontanus is in the Center for Plant Conservation´s National Collection of Endangered Plants.

AREOLES: nearly circular, ca. 2 mm in wide; spines in a radial pattern. FLOWERS: 16-22(-25) cm long, 7-8(-12) cm wide. FRUITS: (6-) 7.5-10.5 cm long, 3-5 cm wide. 2n = 22. NOTES: See also parent taxon for further description. Sonoran Desert, sandy or gravelly loams, creosote-bush - bursage flats, edges of washes and on slopes of small hills: Cochise, Gila, Graham, La Paz, Maricopa, Pima, Pinal, Santa Cruz, Yavapai, Yuma cos.; 300-1100 m (1000-3500 ft); May-Jul; Son., Mex. REFERENCES: Pinkava, Donald J. 1995. Cactaceae. J. Ariz. - Nev. Acad. Sci. 29(1): 2, 6.