Buckthorn — The Buckthorns (Rhamnus) are a genus (or two genera, if Frangula is treated as distinct) of about 100 species of shrubs or small trees from 1-10 m tall (rarely to 15 m), in the buckthorn family Rhamnaceae. They are native throughout the temperate and subtropical Northern Hemisphere, and also more locally in the subtropical Southern Hemisphere in parts of Africa and South America.
Both deciduous and evergreen species occur. The leaves are simple, 3-15 cm long, and arranged either alternately or in opposite pairs. One semi-unique characteristic of many buckthorns is the way the veination curves upward towards the tip of the leaf. The plant bears fruits which are dark blue berries. The name comes from the fact that there is a woody spine on the end of each twig in many species. Buckthorns are used as food plants by the larvae of some Lepidoptera species â€“ see list of Lepidoptera that feed on buckthorns.