Body solitary, spherical to cylindrical grey to waxy blue. Ribs at least 15-30, tuberculate. Central spine 1, red to brown, radials 7-9. Fruit yellow.

NW Mexico, USA (Arizona)

var. rectispinus (Engelm.) N.P. Taylor has central spines sometimes over 20 cm long.

Source: Thompson, A, ; Forbes, S.; Spencer, R. (1997). Cactaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.