Body round to elongate, 10-50 cm high, 10 cm wide with (4-)5(-8) acute ribs; surface typically densely scurfy and whitish. Areoles prominent, spineless. Flowers yellow, sometimes reddish in centre, 4-6 cm wide.
Listed cultivars include 'Columnare' with elongated body, 'Lotusland' and 'Nudum'.
var. coahuilense (Kayser) Borg has flowers distinctly reddish in centre.
var. quadricostatum (Moeller) Borg has a body with only 4 ribs.
var. strongylogonum Backeb. has a green body.
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.