Dimorphotheca is a southern African genus, belonging to the family Asteraceae, and is found in South Africa (Western and Northern Cape) and Namibia. It consists of 15 species. The genus name Dimorpotheca means fruits with two forms and is derived from Greek dis, meaning two, morphe, shape or form and theka, a fruit, referring to the different kinds of seeds produced by the ray and the disc florets in some species, where the fruits formed by the ray florets are wingless and stick-like and the fruits formed by the disc florets are flattened and 2-winged.

Dimorphotheca nudicaulis var. nudicaulis, commonly known as Cape Oxeye in English and Wildemagriet or Witmargriet in Afrikaans and synonymously known as Calendula nudicaulis, Castalis nudicaulis, Castalis nudicaulis var. nudicaulis or Dimorphotheca nudicaulis var. kraussii, is a South African endemic flowering perennial found in the Northern Cape and Western Cape provinces. It grows into a roughly glandular, tufted shrublet forming clumps up to 30cm. The leaves are crowded at the base, narrowly oblanceolate to oblanceolate and has toothed margins. The flowers, which appear in spring, are radiate, solitary on elongated stalks, white rays with purple to copper on the reverse and a purple disc of florets.