Shrubs, with few to many branches, at acute and obtuse angles. Stem segments gray-green, 10-25(-50) cm; tubercles very prominent and broad, 2.5-4.5 cm. Spines 6-11(-14) per areole, rarely interlacing with spines of adjacent areoles, yellow to deep red-brown, aging gray, not baggy sheathed; major abaxial spines usually deflexed and spreading. Flowers: inner tepals yellow to bronze. Fruits bearing few spines, sometimes spineless; areoles 12-20. 2n = 22. Flowering mid-late spring (Apr-Jun). Sonoran and Mojave deserts, desert grasslands, chaparral transition areas, rocky hills, ridges; 600-1500 m; Ariz.

PLANT: Trees and shrubs with few to many branches, at acute and obtuse angles. STEM: segments gray-green, 10-25(‑50) cm long; tubercles very prominent and broad, 25-45 mm long. SPINES: yellow to deep red-brown, aging gray, 6-11(-14) per areole, rarely interlacing with spines of adjacent areoles, not baggy-sheathed; major basal spines mostly deflexed and spreading. FLOWER: inner tepals yellow to bronze. FRUIT: bearing few spines, sometimes spineless; areoles 12-20. 2n = 22. NOTES: See also parent taxon. Desertscrub, desert grasslands, chaparral transition areas, rocky hills and ridges; Gila, Maricopa, Pinal, Yavapai cos.; 600-1450 m (1900-4700 ft); Apr-Jun. Hybridizes with C. whipplei in Yavapai Co., as C. congesta (Griffiths) Pinkava, this hybrid as a compact shrub with long-tubercled stem segments, 8-12 mm thick, bearing 0-4 erect to deflexed spines per areole, and tuberculate, green to yellowish fruits occasionally bearing 1-few spines, 2n = 22. REFERENCES: Pinkava, Donald J. 1999. Cactaceae. Ariz. – Nev. Acad. Sci. 32(1).