Corylus avellana, the common hazel, is a species of hazel native to Europe and western Asia, from the British Isles south to Iberia, Greece, Turkey and Cyprus, north to central Scandinavia, and east to the central Ural Mountains, the Caucasus, and northwestern Iran.
The fruits are a conical pod with seeds contained in holes in the pod. When the seeds are ripe, they become loose in the pod. The pod then tips down towards the water, releasing the seeds.