Irish Moss (Chondrus crispus) has long been a popular food, used most frequently to prepare blancmange. Irish moss is over 60% carrageenin, which is extracted and used as a gel in industry, pharmacy and as a thickener in soups and dairy products. This seaweed grows to a height of 17 to 25 cm (7 to 10"). The blades are flattened and forked repeatedly ranging from a dark purplish red to brown, green, yellow or white, depending on the exposure to sunlight. This sample was photographed on Prince Edward Island in Canada.