The genus Trichodiadema, comprised of around thirty species, is found in southern Namibia and in the Northern, Western, and Eastern Cape Provinces in South Africa. The small shrubby plants are characterized by the diadems of small radiating hairs at the leaf tips. In addition, many species possess a caudiciform base or tuberous roots. They flower from winter to late spring and normally after good rains. The plants are easy to grow and prefer full sun and need adequate water during the blooming season.

Trichodiadema densum commonly known as Desert Rose in English and Kareemoervygie in Afrikaans is not a cactus but could be mistaken for one; its leaves are succulent and end in a circle of stiff hairs, giving the plant a similar appearance to some species in the cactus genus Mammillaria.