Stem segments appearing spiny from afar, obscuring strongly mammillate tubercles beneath. Spines of stems interlaced with spines of adjacent areoles, longest usually 2.5-3 cm; sheaths baggy. 2n = 22, 33. Flowering spring-fall (Apr-Sep). Sonoran desert scrub, sandy flats, rocky slopes, rolling hillsides; 300-1100 m; Ariz.; Mexico (Sonora); escaped in South Africa.

SPINES: of stems interlaced, the largest spines usually 2.5-3 cm long, their sheaths baggy. STEM: appearing spiny from afar, obscuring the strongly mammillate tubercles beneath. 2n = 22, 33. NOTES: See also parent taxon. Sandy desert flats to rocky slopes of rolling hillsides; Cochise, Gila, Maricopa, Pima, Pinal, Yavapai, Yuma cos.; 300-1100 m (1000-3600 ft); Apr-Sep; Son. in Mex. REFERENCES: Pinkava, Donald J. 1999. Cactaceae. Ariz. – Nev. Acad. Sci. 32(1).