This brown seaweed, from the northen atlantic ocean, has long olive-brown fronds, with large egg-shaped air-bladders, set in series at regular intervals. The fronds, which can reach 2m length, are used to hold on to rocks and boulders. When one of the fronds is damaged, it has the ability to regenerate it.

Ascophyllum nodosum is a diploid plant which produces gametes in conceptacles in receptacles on short branches. Eggs, with a molecular sperm attracant, and sperm are released into the water.

It is use in alginates, fertilisers, and for animal and human consumption.