Hazel belongs to the same family of trees as the birch (family Betulaceae), however it is often described as a bush rather than a tree, as it tends to produce several 'trunks' or shoots rather than just one (3). The brown bark is shiny, and tends to peel away in horizontal strips. The twigs are covered in short hairs (2); the roundish leaves have serrated edges, reach 10 cm in length, and are also hairy (4). The male flowers are in the form of pendulous pale yellow catkins, which are known as 'lamb's-tails' (5); they open in February, a time when most other trees are leafless, and are one of the first harbingers of spring (3). The female flowers appear on the same branches as catkins, they are small red tufts on swollen bud-like structures, and it is these that develop into hazel nuts after fertilisation. The edible nuts grow in groups of up to four; they reach 2cm in size and are sheathed by papery modified leaves (3). The English name for this tree derives from the Anglo-Saxon 'haesel knut'; haesel means cap or hat, and refers to the papery cap of leaves on the nuts (6).