Solitary or in clusters and sometimes forming a mound, distinctly grey to powdery white, body apex yellow to white woolly. Ribs 12-47, mostly low and slightly tuberculate. Areoles with 0-4 central spines and 0-12 radial spines.
This is a rarer species.
var. cinerea has 12-30 ribs and areoles with 1-11 blackish thick spines.
var. gigantea (Backeb.) N.P. Taylor has 14-37 rounded ribs, body apex with orange-brown wool and areoles with 3-16 yellowish-brown thin spines. [C. haseltoniana Backeb., C. cinerea var. haseltoniana (Backeb.) N.P. Taylor]
C. krainziana F. F. Ritter is similar to the above but with finer, more densely distributed spines.
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.