Shrubs, sprawling, with numerous branches, usually at obtuse angles. Stem segments green to dark green, 8-20(-31) cm; tubercles salient, moderately broad, 1.5-2.5 cm. Spines 14-18(-23) per areole, yellow to deep red-brown, aging gray, not baggy sheathed; major abaxial spines usually deflexed, spreading. Flowers: inner tepals yellow, bronze, or brick red. Fruits spiny; areoles 14-22(-26). 2n = 22. Flowering spring (Mar-Jun). Sonoran Desert, sandy flats, washes, rocky slopes; 300-900 m; Ariz.; Mexico (Sonora). Cylindropuntia acanthocarpa var. major hybridizes with C. bigelovii (= C. campii M. A. Baker & Pinkava).

PLANT: Shrubs sprawling, with numerous branches, mostly at obtuse angles. STEM: segments green to dark-green, 8-20(-31) cm long; tubercles salient, moderately broad, 15-25 mm long. SPINES: yellow to deep red-brown, aging gray, not baggy-sheathed, 14-18(-23) per areole; major basal spines mostly deflexed, spreading. FLOWER: inner tepals yellow to bronze to brick-red. FRUIT: spiny; areoles 14-22(-26). 2n = 22. NOTES: See also parent taxon. Sandy desert flats and washes to rocky slopes; Maricopa, Pima, Pinal cos.; 300-900 m (1000-2900 ft); Mar-Jun; n Son. in Mex. Hybridizes with: C. bigelovii var. bigelovii near Phoenix, AZ, this hybrid appearing similar but as a slightly more open tree than C. bigelovii var. bigelovii, with yellow green inner tepals and magenta filaments, 2n = 44.; C. leptocaulis (see C.tetracantha); C. spinosior, this hybrid as a sprawling shrub with irregular branching pattern, the spines clusters with 1 or more spines longer than others, the fruits fleshy, some with 1-few spines per fruit, 2n = 22, Pinal Co.; C. versicolor in Pima and Pinal cos, this hybrid with fleshy tuberculate fruits but often with 1-2 short permanent spines at apex and longer and more numerous spines per stem areole. REFERENCES: Pinkava, Donald J. 1999. Cactaceae. Ariz. – Nev. Acad. Sci. 32(1).