Quaqua mammilaris is exceptionally widely distributed in the semi-desert and desert areas of South Africa and also occurs in Namibia. The species is found in the Little Karoo, Great Karoo, the Richtersveld and some records also state the Klinghardt Mountains in Namibia.
The plants have hard stout tubercles on their stems. Quaqua mammilaris has clusters of blackish flowers borne on the upper half of the stem.
Quaqua mammilaris in habitat in the Tanqua Karoo.