Body solitary or rarely in clusters, mostly to about 25 cm tall and 15 cm wide. Ribs generally in indistinct spirals. Tubercles large bearing short-furrowed areoles without a nectary. Central spines 1-4 to about 5 cm long. Radial spines 10-23 to about 2 cm long. Flower 3-4 cm wide, purplish to white, yellow or orange. Fruit dry at maturity, opening by a basal pore.

NE Mexico

There are 3 varieties, the two keyed out being the most readily available. T. macdowellii (Quehl) Glass is occasionally grown; it differs in having 15-25 fine radial spines that are yellow to white (not dark or grey), and magenta flowers.

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.