The plant has a flattened main stipe that is zigzagged. Less than 1 m in height. Side branches alternate and are often closely zigzagged at the lower end, branching near the tips.. Has oval vesicles with no tip. Attaches with a small cone shaped holdfast. The colour is dark grey-brown, dries black and the texture is leathery and slippery when the plants are fertile.

Found in the low intertidal and upper subtidal zones, attached to rock on open coasts.

Uses the sun's energy for photosynthesis.

NZ Seaweeds. An Illustrated Guide: Nelson.