Common Names: Bladder wrack, bladderwrack, black tang, rockweed, bladder fucus, sea oak, black tany, cut weed, dyers fucus, red fucus, rock wrack
A seaweed found on the coasts of the North Sea, the western Baltic Sea, and the Atlantic and Pacific Oceans. It was the original source of iodine, discovered in 1811, and was used extensively to treat goitre, a swelling of the thyroid gland related to iodine deficiency. The fronds grow to 90 cm long and 2.5 cm 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. The margin is smooth and the frond is dichotomously branched.
Primary Flower Color: None
Secondary Flower Color: None