Common Hazel (Corylus avellana)
Common hazel is typically a shrub reaching 3 to 8 metres tall. The leaves are deciduous, rounded, 6 to 12 centimetres long and across, softly hairy on both surfaces, and with a double-serrate margin. The flowers are produced very early in spring, before the leaves, and are monoecious with single-sex wind-pollinated catkins. Male catkins are pale yellow and 5 to 12 centimetres long, while female catkins are very small and largely concealed in the buds with only the bright red 1 to 3 millimetres long styles visible.
The fruit is a nut, produced in clusters of one to five together, each nut held in a short leafy involucre ("husk") which encloses about three quarters of the nut. The hazelnut is roughly spherical to oval, 15 to 20 millimetres long and 12 to 20 millimetres broad, yellow-brown with a pale scar at the base. The nut falls out of the involucre when ripe, about 7 to 8 months after pollination. The fruit, also known as cobnut, is edible. It is rich in protein and unsaturated fat. Moreover, it contains significant amounts of manganese, copper, vitamin E, thiamine, and magnesium.
The shrub is 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.
Source: en.wikipedia.org/wiki/Corylus_avellana - 24.10.2017
Male and female flowers of this widely spread shrub look extremely differently.
These male catkins are not fully unfolded yet.