Twistspine Pricklypear

Plants of Opuntia pottsii that are intermediate morphologically to O. macrorhiza are known in Arizona.

Shrubs, forming clumps, to 0.4 m, often from tuberlike rootstocks. Stem segments not easily detached, dark green, cuneate-obovate to commonly rhombic, 5-20 × 4-8 cm, fleshy but firm; areoles 4-6(-8) per diagonal row across midstem segment, oval to subcircular, 2-4 mm diam.; wool tan. Spines (0-)1-6 per areole, usually in distal 40% of stem segment, gray-white to red-brown, erect or reflexed, terete or proximal ones flattened, sometimes spirally twisted, longest to 60 mm, very slender, 0.2 mm diam. Glochids well developed in adaxial tuft , yellow or tan to brown-red, aging dull brown, to 6 mm. Flowers: inner tepals red throughout or with red basal portions, 25-35 mm; filaments pale yellow; anthers yellow; style whitish; stigma lobes cream to yellow. Fruits green to yellowish to dull red, long stipitate, elongate-obovoid, 25-40 × 15-40 mm, fleshy, base not narrowed, glabrous, spineless or nearly so; umbilicus deep; areoles 14-26. Seeds tan to gray, subcircular, 4-5 mm, thickish, warped; girdle protruding to 0.5 mm. 2n = 44.

Ariz., N.Mex., Tex.; Mexico (Chihuahua).

Flowering late spring-early summer (May-Jul).

Plains, hills, sandy or loamy soils; 900-1900m.

Opuntia ballii Rose; O. delicata Rose; O. filipendula Engelmann; O. macrorhiza Engelmann var. pottsii (Salm-Dyck) L. D. Benson

Opuntia pottsii is a species of flowering plant in the family Cactaceae, native to Arizona, New Mexico and Texas in the United States and to northeast Mexico. It was first described by Joseph zu Salm-Reifferscheidt-Dyck in 1850.