• A marine alga, Porphyra tenera or P. umbilicalis, found on the surface of the sea off Japan, China and Korea. It is formed into paper-like sheets, compressed and dried and has a colour ranging from green through purple. It is used in Japan to wrap around rice and various fillings to make sushi. It may also be shredded for use as a condiment or flavouring or may be formed into baskets by deep frying.