Like tiny scarlet goblets, waxy-looking flowers cover clumps of bristly, cylindrical stems that often squeeze between boulders and along cracks in rocks, or form rounded mounds of 5–20+ stems. The stems reach 8–inches tall, 4-inches wide, with 6–14 ribs lined with straight spines. Note the short, white felt on the areoles at the base of the spines, and the flowers grow from the upper stem, not the apex. This species has separate male and female plants.

FLOWER: March–June. The 1–2 1/2-inch wide (3–7 cm) flowers develop on the sides of the stem and have stiff, round-tipped, red petals (tepals), often with greenish-white or yellowish bases, and a green stigma that stands above the cluster of filaments with pinkish-purple anthers. Male plants produce grayish-purplish pollen and females produce fruit. Fruit is egg-shaped, 3/4–1 1/2-inches long (20–38 mm), fleshy, green maturing red with white pulp, and with clusters of tiny spines until ripe.

SPINES: Rounded (not narrow, elongated) areoles have short, white felt and 1–4 central spines and 7–12+ radial spines; centrals are 1–3-inches (25–75 mm) long and project outward; radials are 3/16–1 1/2-inches long (5–40 mm) and spread over the rib. The large central spines taper and are usually round, not angled, in cross-section.

HABITAT: Gravelly, sandy soils, rocky foothills, canyons, slopes; desert grasslands and scrub to mountain ridges in spruce-fir forests.

ELEVATION: 4,200–10,000 feet.

RANGE: AZ, CA, CO, NM, NV, TX, UT.

SIMILAR SPECIES: This species forms hybrids with the yellow-flowering Texas Rainbow Cactus, E. dasyacantuus, widespread in NM. The crosses, E. x roetteri, occur in Otero Co. and adjacent Texas, and bloom with a rainbow pallet of flower colors. Kingcup, E. triglochidiatus, in much of the state, has 5–8 ribs, areoles also with short, white felt, 1–10 radial spines, and 0–1 central spine angular in cross-section. The E. triglochidiatus complex originally included E. coccineus. Arizona Claret Cup, E. arizonicus, in sw NM, has stems that reach 4–6-inches wide with 9–10 ribs.

NM COUNTIES: Statewide in mid- to high-elevation habitats except Chaves, De Baca, Lea, Quay, Roosevelt, Union counties.

NOTES: Unlike most cacti with  yellow to purple flowers with weak, pointed petals adapted for insect pollination, claret cups and kingcups have bright red flowers to attract hummingbirds, rounded petals rigid enough for a perch, and remain open 2–3 days. The flowers are sized to fit hummingbirds heads, while plants with red, tubular flowers are sized to fit hummingbird bills.