Stems solitary or in clusters, pale to grey-green, compressed spherical, arising from a tuberous root. Ribs 10-17, tuberculate. Central spines 0-3, radial spines 4-9, black to grey. Flowers to 4 cm long. [C. mollicula F. Ritter]
One of a group of species related to N Chilean C. cinerascens (Salm-Dyck) Britton & Rose with central spines to 6 cm long and radial spines up to 5 cm long including the densely spiny C. serpentisulcata F. Ritter.
Source: (1997). Cactaceae. In: . 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.