Thornber cholla

Opuntia thornberi Thornber & Bonker, Fantast. Clan, 133, 135 (fig.), 148. 1932; O. acanthocarpa Engelmann & J. M. Bigelow var. thornberi (Thornber & Bonker) L. D. Benson

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.