Thaumatococcus daniellii is a plant species from Africa, known for being the natural source of thaumatin, an intensely sweet protein which is of interest in the development of sweeteners. When the fleshy part of the fruit is eaten, this molecule binds to the tongue's taste buds, causing sour foods to taste sweet. It is a large, rhizomatous, flowering herb native to the rainforests of western Africa from Sierra Leone to Zaire. It is also an introduced species in Australia and Singapore.