seaweed [1]
Usually aquatic vegetables used in cooking or as dietary supplements; they are primarily produced and eaten by the Japanese.
spirulina 
Microscopic freshwater alga, rich in nutrients (protein, iron, magnesium); it is used mainly as a dietary supplement.
Irish moss 
Plentiful in the North Atlantic, it can only be eaten cooked; also produces carrageen, a substance used to thicken certain dishes.
kombu 
Eaten since ancient times, it is sold in large blackish strips; it is used primarily as an ingredient in broth or to make a kind of tea.
arame 
Milder and less crunchy than hijiki, it is used mainly in salads and soups or served fried as a side vegetable.
wakame 
Popular with the Japanese, it is rich in calcium and has a delicate texture and flavor; among its many uses, it is a often served with legume dishes.