Buckthorn

Buckthorn, common name for thorny shrub (Rhamnus cathartica) of the family Rhamnaceae. It has oval leaves and small, green flowers that grow in clusters. Its fruit resembles small black berries. Buckthorns are sometimes grown to form hedges and may reach a height of 12 ft (3.7 m). The bark is used to produce a yellow dye. Buckthorns are found in Europe and the United States.