Citrullus ecirrhosus, commonly known as Namib Tsamma, is a species of perennial desert vine in the Cucurbitaceae (gourd) family, a relative of the widely consumed watermelon (Citrullus lanatus). It can be found in both Namibia and South Africa, in particular the Namib Desert.
The vines can crawl for up to two metres, and it has yellow flowers. As a desert plant it is a hardy species, surviving with little water and lots of sunlight. The leaves form annual stems which die back each year. The plant relies on water deep in the ground and morning fogs. It is an important source of water for other desert fauna. The bitter-tasting fruit it produces are known as Tsamma melons.