water potato
Pterodiscus speciosus Hook.

Pterodiscus speciosus, commonly known as water potato, is a species in the Pedaliaceae family. It was first described in 1844 by Hook. and is native to regions including Botswana, the Cape Provinces, the Free State, and the Northern Provinces.
Description
Pterodiscus speciosus is a member of the Pedaliaceae family, a group of flowering plants commonly referred to as the sesame family. The species is indigenous to southern Africa, where it is found in Botswana, the Cape Provinces, the Free State, and the Northern Provinces. The plant is known by the common name water potato. The species was formally described in 1844 by the botanist Hook. This species contributes to the biodiversity of its native regions and is part of the genus Pterodiscus, which includes several other related species.
Other common names
water potato
Distribution
Botswana · Cape Provinces · Free State · Northern Provinces
Synonyms
Harpagophytum pinnatifidum