Species:

Note: The species is dichotomously or irregularly branched, with branches becoming gradually thinner. During the development individuals become partly hollow in older parts. The species has large inner cells and angular outer cortex cells, and grows by a top cell, formed by a central cell axis. The species is present during summer and can grow to 30-40 cm long, attached to other algae or laying loose on the bottom of sheltered bays. It When fertile it develops small sori with paraphyses, unilocular sporangia and hairs in groups, scattered on the surface.