Plants reach 1.5m high. The main stem (stipe) is flattened, the blades come off alternately and are flattened and lie in one plane. It has vesicles (gas bladders) which are stalked and ellipsoid. The holdfast is flattened with lateral, peg-like attachments. The colour is dark brown and the texture leathery, tough and pliable.

Found on rock at low water in pools and channels it can form a distinct band especially on vertical rock faces.

Uses the sun's energy for photosynthesis.

Common relative of the seaweed known as “wrack" in Britain."

Seaweeds of NZ; Adams