Stems 4-34.5 × 4-10 cm; ribs 18-21; areoles 8-19 mm apart along ribs; areolar glands present at least seasonally. Spines 13-19 per areole, purplish pink to purple or nearly white with brown tips; radial spines 12-18 per areole; abaxial (shortest) radial spine 6-20 × 0.3-0.6 mm; adaxial and lateral (longest) radial spines 9-37 mm; central spines 1-3(-4) per areole (usually absent from sexually immature plants), erect to ascending, 12-44 × 0.5-0.8 mm; longest adaxial central spine straight to curved upward, abaxial central spine 13-35 mm (absent in var. erectocentrus). Flowers 3.6-6 × 4-9 cm; inner tepals whitish to bright rose-pink or lavender, basal portions olive-green to orangish brown, chestnut or maroon, (2-)2.5-4.3 × 0.6-1.8 cm; stigma lobes red to brownish red, papillae red or green. Fruits dehiscent by vertical slits, ellipsoid-cylindric, 12-20 × 5-8+ mm. 2n = 22. The populations of Echinomastus erectocentrus north of Tucson, Arizona, are geographically, ecologically, and morphologically intermediate between the two named varieties. Echinomastus erectocentrus is replaced to the northwest by E. johnsonii; the two species are only weakly differentiated.