The Bladder Wrack (Fucus vesiculosus), is a type of brown seaweed whose stem has gas filled bladders that help its leafy fronds float. It grows to more than a metre long and is very common throughout the UK on rocky beaches. It will bind itself to rocks. It is used to treat constipation, heartburn and diarrhoea.

Bladderwrack - WWC Archives


The fronds of F. vesiculosus have a prominent midrib and almost spherical air bladders which are usually paired but may be absent in young plants. The margin is smooth and the frond is dichotomously branched. It is sometimes confused with Fucus spiralis with which it hybridizes.


Fucus vesiculosus is one of the most common algae on the shores of the British Isles. It has been recorded from the Atlantic shores of Europe, Northern Russia, the Baltic Sea, Greenland, Azores, Canary Islands, Morocco and Madeira.[1]It is also found on the Atlantic coast of North America from Ellesmere Island, Hudson Bay to North Carolina.


The species is especially common on sheltered shores from the middle littoral to lower intertidal levels. It is rare on exposed shores where any specimens may be short, stunted and without the air vesicles. F. vesiculosus supports few colonial organisms but provides a canopy and shelter for the tube worm Spirorbis spirorbis, herbivorous isopods, such as Idotea and surface grazing snails such as Littorina obtusata.


Plants of F. vesiculosus are dioecious. Gametes are generally released into the seawater under calm conditions and the eggs are fertilized externally to produce a zygote. Eggs are fertilised shortly after being released from the receptacle.

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