Opuntia basilaris Engelmann & J. M. Bigelow var. aurea (E. M. Baxter) W. T. Marshall; O. erinacea Engelmann var. aurea (E. M. Baxter) S. L. Welsh

Shrubs, forming low clumps or with trailing branches, 10-30 cm. Stem segments not disarticulating, green to blue-green, flattened, elliptic to obovate, 6-15 × 5-12 cm, low tuberculate, papillate; areoles 7-11 per diagonal row across midstem segment, subcircular to elliptic, 3-5 × 2-4 mm; wool tan. Spines absent or only l spine in 1-few distal areoles, deflexed, yellow to gray, straight, terete, to 10 mm. Glochids in dense crescent at adaxial margin of areole and dense subapical tuft, yellow, to 6 mm. Flowers: inner tepals yellow throughout (magenta in introgressed plants), 25-30 mm; filaments white to yellow; anthers yellow; style white; stigma lobes green. Fruits tan to gray, 25-30 × 15-20 mm, dry, spineless; areoles 12-18. Seeds tan, subspheric to irregularly shaped, flattened, very large, 9-12 mm diam.; girdle thick, protruding 2.5-3.5 mm. 2n = 66.

Flowering late spring (May-Jun). Pinyon-juniper woodlands, red sands; 1500-1800 m; Ariz., Utah.

Opuntia aurea forms hybrids with O. polyacantha var. erinacea and O. phaeacantha, and forms hybrid swarms with O. pinkavae (B. D. Parfitt 1991).