Senecio arenarius, in Afrikaans the hongerblom (hungry flower) is a branching annual growing to 40 cm, although often only half that.

The plant is similar to S. elegans, but has hairy bracts. These fine hairs are gland-tipped. They cover the green bracts on the cylindrical involucre at the base of the hongerblom flowerhead. The bracts on S. elegans flowers are smooth, green and have brown tips.

The leaves of S. arenarius are lobed or toothed and also covered by these gland-tipped hairs. The flowerheads have mauve, sometimes white ray florets and yellow central discs. They appear from late winter to mid-spring (Manning, 2007; Bond and Goldblatt, 1984).