Bladderwrack (Fucus Vesiculosus) known by the common names black tang, rockweed, bladder fucus, sea oak, cut weed, dyers fucus, red fucus, and rock wrack is a seaweed found on the coasts of the North Sea, the western Baltic Sea, and the Atlantic and Pacific Oceans. The fronds of F. vesiculosus grow to 90 cm (35 in) long and 2.5 cm (1.0 in) wide and have a prominent midrib throughout. It is attached by a basal disc-shaped holdfast. It has almost spherical air bladders which are usually paired, one on either side of the mid-rib, but may be absent in young plants.
