Sessile oak (Quercus petraea)

Sessile oak, also known as Durmast oak, Chestnut oak

The sessile oak (Quercus petraea), native to Europe and widespread in the British Isles, is Ireland's national tree. Its name reflects its distinctive acorns, which grow directly on the branches without stems. This tree supports a variety of wildlife, including being a preferred food source for the caterpillars of purple hairstreak butterflies.