Body solitary or in groups, compressed spherical. Tubercles forming about 30 spirals. Areoles narrowed. Spines about 14-16, radial in comb-like arrangement, white to yellow or brown. Flowers orangish yellow.

 

Other species with narrowed areoles include the magenta to purple R. tiraquensis Cárdenas and R. mentosa (F. Ritter) D.R. Hunt, the former with marked colour contrast of radial and central spines; R. rauschii (G. Frank) D.R. Hunt has white flowers with a purple throat.

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. (as Rebutia arenacea)