Corylus colurna

Turkish filbert or Turkish hazel is in the birch or Betulaceae family and is the largest hazel, being is native from the Balkans to Turkey, growing to be a dense, conical large tree and widely cultivated as an ornamental tree in Europe and North America. It is distinguished from the common hazel in its large tree size and in having more of a spiny and bristly husk.

• Leaves are alternate, simple, coarsely double-toothed, blunt-pointed and broadly oval, up to 17 cm long, 15 cm across.
• Species is monoecious. Flowers are borne in very profuse catkins during late winter before the foliage emerges. Male catkins are up to 11 cm in length, yellow and drooping. Female catkins are very small and red.
• Nut is small size in a deeply-lobed husk, with a very hard, thick nut shell, so it often has low commercial value. However, it is important in commercial hazelnut orchards as ideal rootstock on which to graft nut-bearing common hazel cultivars.