Solitary, body globular, to 10 cm wide, with milky sap. Tubercles prominent, conical. Axils at first woolly. Central spine solitary, 6 mm long, brown. Radial spines 15-22, 5-8 mm long, white, tips brownish, bristle-like. Flowers cream, with brownish or greenish central stripe, 2-2.5 cm long. Fruit scarlet.

SW North America, N Mexico

There are several varieties differing in spination, flower-size and colour.

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.