Wolf cholla

Opuntia echinocarpa Engelmann & J. M. Bigelow var. wolfii L. D. Benson, Cact. Succ. J. (Los Angeles) 41: 33. 1969; O. wolfii (L. D. Benson) M. A. Baker

Shrubs, ± erect, densely branched, 0.5-1.1(-1.5) m. Stem segments yellow- to gray-green, 6-40 × 2.5-4 cm; tubercles prominent, 1-1.5(-2) cm; areoles subcircular to obdeltate, 5-7 × 4.5-5 mm; wool tan to yellow, aging gray. Spines 12-25(-30) per areole, gold to pale brown, aging dark brown, longest to 3 cm; sheaths translucent yellow to pale brown. Glochids in adaxial tuft and scattered along margin, yellow to pale brown, of irregular lengths. Flowers: inner tepals yellow-green suffused with bronze, pale red, or purple-brown, 20-35 mm; filaments dark bronze-red to magenta; anthers yellow, sometimes sterile; style rose-pink (at least distally); stigma lobes cream. Fruits grayish tan, 25-30 × 15-30 mm, dry, tuberculate, densely spiny; tubercles prominent, subequal or basal ones longest; areoles 24-32. Seeds rare, tan, circular, flattened, 5-6 mm diam., with 1-2 shallow depressions; girdle smooth. 2n = 66.

Flowering spring (Mar-May). Dry, rocky slopes; 300-1200 m; Calif.; Mexico (Baja California).