Strychnos is a genus of flowering plants, belonging to family Loganiaceae (sometimes Strychnaceae). The genus includes about 100 accepted species of trees and lianas, and more than 200 that are as yet unresolved. The genus is widely distributed around the world’s tropics. The genus is noted for the presence of poisonous indole alkaloids in the roots, stems and leaves of the plant. Among the alkaloids are strychnine and curare.

Strychnos potatorum commonly known as Black Bitterberry or Clearing-Nut Tree is a South African indigenous species from the Limpopo Province. It is synonymously known as Strychnos stuhlmannii. The seeds of the tree are commonly used in traditional medicine as well as for purifying water in India and Myanmar. Strychnos potatorum grows into a tree of 5 meters to 15 meters tall. It has pale silvery-grey bark and during summer it bears white to yellowish-green flowers which are followed by round fleshy blue-black grape-like fruit.