Stem segments obovate, 15-23 × 14-18 cm, to 1.5 times longer than wide. Spines (0-)1-7 per areole, evenly distributed on stem segments, arching downward, yellow with extreme reddish brown basal portions, aging deep red to black, often twisted, the longest 65-75 mm, smaller ones depressed, whitish. 2n = 66. Flowering spring (Apr-May). Sonoran Desert, sandy bajadas; 500-800 m; Ariz.; Mexico (Sonora).
PADS: obovate, 15-23 cm long, 14-18 cm broad. SPINES: evenly distributed on pads, yellow with reddish brown extreme bases, aging deep red to black, arching downward, often twisted, (0-)1-7 per areole, the major ones 6.5-7.5 cm long, a smaller one depressed, whitish. 2n = 66. NOTES: See also parent taxon. Sandy bajadas, Sonoran Desert; Maricopa, Pima, Yavapai cos.; 500-800 m (1700-2700 ft); Apr-May; adjacent Mex. REFERENCES: Pinkava, Donald J. Cactaceae. 2003. J. Ariz. - Nev. Acad. Sci. Volume 35(2).