Castanospora is a monotypic genus of trees, constituting part of the plant family Sapindaceae. The sole species Castanospora alphandii, commonly known as brown tamarind, grows naturally in the Australian rainforests of north-eastern New South Wales and eastern Queensland as far north as the Wet Tropics rainforests of north-eastern Queensland. Brown tamarind is known in horticulture, though it is only distantly related to the true tamarind.