The sea oak is small red algae that grows about 30 cm long. The stems and branches are thin and branched, at the ends of which are red and thin leaves. The sea oak resembles a tiny oak, therefore the name.
It is common in the lower part of the seashore and in shallow seas. It grows on the hard bottom or on other larger alga.
It is found in the entire northern hemisphere but also in the Falkland Islands.
Her it can bee seen with Lithothamnion glaciale which, although very diffrent, also a red algae.