Opuntia monacantha

Erect to arborescent shrub to c. 3.5 m high, trunk usually well-developed, to c. 25 cm diam. Terminal cladodes often drooping, compressed, obovate, narrowed toward base, relatively thin, 10–45 cm long, 6–15 cm wide, glabrous, glossy green; margins sinuate; areoles 2–4(–6) cm apart, filled with whitish wool and yellow to reddish-brown glochids; spines mostly 1 or 2 per areole, 25–50 mm long (up to 12 per areole and to 10 cm long on trunk), 0.7–1.5 mm diam. near base, straight, rigid, spreading, white to brown with yellow or red markings, or reddish. Flowers 3–7 cm diam.; sepaloids tinged crimson; petaloids spreading, yellow, the outer ones tinged crimson; staminal filaments pale yellow; style whitish, stigmas pale yellow; hypanthium more or less tuberculate. Fruit obovoid, shallowly depressed at apex, 4–7.5 cm long, 2–4 cm diam., smooth, spineless, reddish-purple, usually greenish toward base, juicy, long-persistent, often proliferating. Flowers late spring–summer.