Erect shrublet up to 50cm branching from persistent base with slender, wiry, hairless stems. Leaves are opposite below, sessile, linear and lance-shaped, pressed to the stem. Flowers, bright yellow, often tinged with orange, solitary or few in panicles.

After: Carl Peter Thunberg (1743-1828), Swedish botanist and physician who travelled as surgeon with ships of the Dutch East India Company and did extensive botanical exploration in South Africa.