Oaks are in the genus Quercus which is in the Beech family. There are more than 600 species worldwide. There are two native oaks in Britain, the English Oak and the Sessile Oak . Three more oaks are shown here but there are many more species in parks, urban settings or botanical gardens in Britain. These five species show many of the key characteristics of the oak genus. Leaves are often but not always lobed, male and female flowers are on the same tree. Male flowers are on catkins and release pollen onto the wind. Female flowers are tiny and difficult to see. Fruits are in the form of acorns with nuts sitting in ‘cups’
The English Oak leaf has a very short stalk, hidden by two small leaves known as “ears” at the base of the leaf.
The Sessile Oak leaf has a long stalk.
The Turkey Oak leaf has deeply cut lobes
Holm Oak evergreen leaves are glossy
Cork Oak evergreen leaves have small lobes.
English Oak male catkins in May
Sessile Oak male catkins in May
Turkey Oak male catkins in May
Holm Oak male catkins in May
Cork Oak male catkins in June
An English Oak acorn, which is on a long stalk called a peduncle.
Sessile Oak acorns have no stalk. They sit on the shoot like this – a feature that is known as ‘sessile’ by botanists.
Turkey Oak acorn with its whiskered ‘cup’
Holm Oak acorn
Cork Oak acorn