Solitary or eventually clustering, body elongate, 2-3 cm wide, to 20 cm high, without milky sap. Tubercles prominent, conical. Axils bare or woolly. Central spines, 1-4, 4-8 mm long, white, tips brown. Radial spines 10-15, 5-8 mm long, whitish, tips speckled red. Flowers purplish-red, 15 mm long and 8 mm wide. Fruit scarlet. [M. viperina J.A. Purpus]

S Mexico

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.