The genus name Didelta is derived from Greek, where di- refers to ‘two’, and delta, which represents a triangle, this describes the two rows of triangular shaped bracts. The species name carnosa, Latin meaning ‘fleshy’, is in reference to the texture of the leaves. The variety name, tomentosa, means ‘white’ or ‘hairy’ and describes the white hairs present on the leaves.

Fig. 6. Didelta carnosa var. tomentosa in bud, showing the distinctive triangular bracts around the flowerhead.

Didelta carnosa was first introduced to Europe in 1774 and described and placed under the genus Polymnia in 1781. However, a colour plate published in 1785 by Buc’hoz revealed the plant to be the same Didelta to not only be cultivated by Trianon, but also named Breteuillia trianensis by him. The name Didelta was first published in 1786 and used on this plant as D. tetragoniifolia. Burtt recommended the name Didelta be used, despite Breteuillia trianensis being the first to be published, as it was more widely used. In 1789 Polymnia carnosa and Polymnia spinosa were transferred to Didelta when Aiton found D. tetragoniifolia to be the same plant described and introduced to Europe in 1774. Joseph Gaertner published D. spinosum as Favonium spinosium, while in 1800 Thunberg created a new genus Choristea, for the Polymnia species. The names were later changed back to Didelta, the name first published in 1786 by L’Heritier.

Didelta, a small genus in the cosmopolitan plant family Asteraceae, consists of only two species: D. carnosa and D. spinosa, spiny salad bush. Two varieties are recognised in D. carnosa: the var. carnosa, coast salad bush, being hairless or thinly hairy becoming hairless. This family, the largest in southern Africa, is also one of the largest in the world. Well-known other genera such as Gazania, Arctotis, Berkheya, together with Didelta, are some of the 25 genera found in the tribe Arctotideae. There are approximately 252 species in the tribe.