Diascia is a genus of around 70 species of herbaceous annual and perennial flowering plants of the family Scrophulariaceae, native to southern Africa, including South Africa, Lesotho and neighbouring areas. The perennial species are found mainly in summer-rainfall areas such as the KwaZulu-Natal Drakensberg; about 50 species, mostly annuals, are found in the Western Cape and Namaqualand, winter rainfall areas. Their common name is twinspur, in reference to the two, usually downward-pointing, spurs to be found on the back of the flower. These help to distinguish them from the similar genera Alonsoa and Nemesia. The spurs contain a special oil, which is collected in the wild by bees of the genus Rediviva (e.g. R. longimanus) that appear to have coevolved with the plants, as they have unusually long forelegs for collecting the oil. In gardens, Diascia cultivars have become extremely popular as colourful, floriferous, easily grown bedding plants in recent years.

Diascia capensis, synonymously known as Anagallis capensis, Diascia nemophiloides, Hemimeris bonae-spei and Paederota bona-spei, and commonly known as Cape Twinspur, is a South African endemic species found in the Western Cape Province around the Barrydale area. Diascia capensis has deeply lobed leaves and from late winter to mid-spring it bears eye-catching greyish purple to wine-red flowers that grow on long stalks. This is an erect or sprawling annual herbaceous plant that branches from the base, reaching 35 cm in height.