Some seaweeds can have a greenish color, but yet are not green seaweeds. Bladder wrack is a good example. It can vary from olive-green to brown. Like all brown seaweeds, it is much sturdier than green seaweeds, which easily tear apart. Bladder wrack is easy to recognize by its bladders along the fronds. The floating bladders help the plant to stand straight up in the water. Bladder wrack grows along dikes, on wooden poles and on mud flats. It attaches itself to mussels, stones or other objects. It can grow up to 0.5 meters long. In earlier days, bladder wrack was used as a fertilizer as well as for a remedy for pain in the joints, swellings and skin diseases. Sometimes, there are no floating bladders and then it is easily confused with spiral wrack.