A large, deciduous tree growing up to 20–30m tall, this species grows and matures to form a broad and spreading crown with sturdy branches beneath.
It’s rather leathery, dark green, lobed leaves to 15cm long, turn orange-brown in autumn. Inconspicuous yellowish flowers in catkins with the young leaves.
Sessile Oaks acorns are stemless and form dierectly from the branch, This is the easisest way to tell it apart from other Oaks.
It will grow on thin acidic soils and is often found on acidic soils, pockets of ancient sessile oak forest are found in coastal counties around Ireland.