Echinomastus erectocentrus var. acunensis
Cact. Suc. Mex. 25: 65. 1980.
Stems 4–16.5 (–27) × 4–9 cm; ribs 21; areoles 15–19 mm apart along ribs. Spines 13–16 per areole, purplish-pink or nearly white with brown tips; radial spines 12–15 per areole; abaxial (shortest) radial spine 11–20 × 0.42–0.59 mm; adaxial and lateral (longest) radial spines 22–37 mm; central spines ascending, (1–) 2–3 (–4) per areole, 19–44 × 0.6–0.8 mm, longest adaxial central spine curved toward apex of plant, sometimes slightly so; abaxial or only central spine 25–35 mm. Flowers 3.6–6 × 4–9 cm; inner tepals pale to bright-rose-pink, proximally blotched orangish brown, chestnut, maroon, or greenish brown, (2–) 3–4.3 × 0.7–1.8 cm; stigma lobes red to brownish red, papillae red to green. 2n = 22.
Phenology: Flowering Mar–Apr; fruiting Apr–May.
Habitat: Arizona Upland Subdivision of Sonoran desert scrub, low gravelly hills, bajadas, and rocky hilltops, igneous substrates
Elevation: 400-800 m
Ariz., Mexico (Sonora)
Echinomastus erectocentrus var. acunensis is in the Center for Plant Conservation’s National Collection of Endangered Plants.