Opuntia engelmannii var. flavispina
Madroño 35: 348. 1988.
Stem segments obovate, 15–23 × 14–18 cm, to 1.5 times longer than wide. Spines (0–) 1–7 per areole, evenly distributed on stem segments, arching downward, yellow with extreme reddish-brown basal portions, aging deep red to black, often twisted, the longest 65–75 mm, smaller ones depressed, whitish. 2n = 66.
Phenology: Flowering spring (Apr–May).
Habitat: Sonoran Desert, sandy bajadas
Elevation: 500-800 m
Ariz., Mexico (Sonora)