Trees or sometimes shrubs, with few branches, usually at acute angles. Stem segments ± yellowish green, 10-30 cm; tubercles salient, elongate, (1.5-)2-3 cm. Spines 18-30+ per areole, yellow to light brown, aging dark gray, baggy sheathed; major abaxial spines deflexed to divergent. Flowers: inner tepals bright yellow. Fruits densely spiny; areoles 16-30. 2n = 22. Flowering spring-early summer (Mar-Jun). Sonoran and Mojave deserts, edges of juniper woodlands, sandy flats, rocky slopes; 400-1200 m; Ariz., Calif., Nev., Utah; Mexico (Sonora).
PLANT: Trees or sometimes shrubs with few branches, mostly at acute angles. STEM: segments yellowish green, 10-30 cm long; tubercles salient, elongate, (15-)20-30 mm long. SPINES: yellow to light brown, aging dark gray, baggy-sheathed, 18-30 per areole, greatly increasing in number with time; major basal spines deflexed to divergent. FLOWER: inner tepals bright yellow. FRUIT: densely spiny; areoles 18-30 or more, 2n = 22. NOTES: See also parent taxon. Deserts to edges of juniper woodlands, sandy flats to rocky slopes; La Paz, Maricopa, Mohave, Pima, Yavapai, Yuma cos.; 400-1200 m (1300-3900 ft); Mar-Jun; CA, NV, UT; Son. in Mex. Hybridizes with C. echinocarpa in La Paz and Maricopa cos. and se CA, this hybrid, C. x deserta (Griffiths) Pinkava, having reddish filaments, short tubercles, variable-length spines per areole, and dry spiny fruits. REFERENCES: Pinkava, Donald J. 1999. Cactaceae. Ariz. - Nev. Acad. Sci. 32(1).