Oval to cylindrical stems of this hedgehog cactus are usually single, but often in a cluster or with several basal branches, and reach 4–9-inches tall and 2–5-inches in diameter. The 15–19 ribs have undulating ridges covered with spines that obscure the stem. Flowers grow from the upper stem, not the apex.

FLOWER: March–May. Showy, yellow (rarely magenta) flowers, 2 3/4–3 3/8-inches long (7–8.5 cm) and 2 3/4–4-inches wide (7–12 cm) with delicate petal-like tepals, vary with up 30 percent green at the base. The outer tepals have red to brownish midstripes. Stamens and anthers are yellow; 12–22 stigma lobes deep green; fruit purplish,  barrel-shaped, 3/4–1 3/8-inches long (2–3.5 cm).

SPINES: Each elongated (not circular) areole has 17–25 pink, yellow, white, or tan, mostly appressed radial spines 1/4–3/4-inch long (7–20 mm) that overlap and often create a “rainbow” of subtle hues. The 4–12 widely spreading, central spines reach 3/16–1/2-inch long (5–12 mm).

HABITAT: Rocky, sandy limestone soils of Chihuahua Desert scrub and grasslands.

ELEVATION: 2,500–5,000 feet.

RANGE: AZ, NM, TX.

SIMILAR SPECIES: All Echinocereus species have spines on the flowering pedicels and unripe fruit; the dense covering of spines and large, yellow flowers identify this species.   Texas Rainbow Cactus forms hybrids with the red-flowering Claret Cup Cactus, E. coccineus, widespread in NM. The crosses, E. x roetteri, occur in Otero Co. and adjacent Texas, and bloom with a rainbow pallet of flower colors.

NM COUNTIES: NE corner and southern half of NM in low-elevation, arid habitats: Chaves, Cibola, De Baca, Dona Ana, Eddy, Hidalgo, Lincoln, Otero, Quay, San Miguel, Socorro, Union, Valencia.