J. Arizona-Nevada Acad. Sci. 32: 50. 1999.
Shrubs, forming mats, to 50 cm, in series of usually 2–4 stem segments. Roots diffuse. Stem segments curved and narrowed at base, 10–15 × 2.5–4 cm; tubercles prominent, 20–30 mm, narrow, 4–6 times longer than wide, obscured by interlacing spines; areoles 5–6 mm in diam.; wool gray-white. Spines 17–27 per areole, ± uniformly distributed along stems; major 4–6 abaxial spines deflexed, tan with whitish margins, strongly flattened, longest to 4.5 cm; major 4–5 adaxial spines divergent, tan to reddish tan, angled at base, longest subterete, to 5 cm. Glochids few in adaxial portion of areole, yellow, 5–6 mm. Flowers: inner tepals yellow to pale yellow-green, to 15–20 mm; filaments white; style light green to white; stigma lobes white. Fruits sometimes proliferating, lemon yellow to yellow, 40–75 × 15–40 mm, fleshy, very spiny, glochidiate; spines (4–) 6–17 per areole, straw yellow to brown, 12–20 mm, retrorsely barbed; areoles (40–) 45–70. Seeds yellowish white, 4–5 ×3.5–4.5 mm, smooth. 2n = 44.
Phenology: Flowering spring (Apr–Jun).
Habitat: Sonoran Desert, silty, sandy, or gravelly flats and hills
Elevation: 200-600 m
Ariz., Mexico (Baja California), Mexico (Sonora)