Plant
Algae comprise several different groups of organisms which produce food by photosynthesis and thus have traditionally been included in the plant kingdom. The seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, the brown, red and green algae. There is good evidence that the brown algae evolved independently from the others, from non-photosynthetic ancestors that formed endosymbiotic relationships with red algae rather than from cyanobacteria, and they are no longer classified as plants as defined here.
Alaria (alga)
In Ireland, Scotland, Greenland, Iceland, Denmark, and the Faroe Islands, the midrib is removed, and the blade and sometimes the leaflets are eaten, although it is not commercially available. It is more commonly eaten in the Far East (China, Japan, and Korea), where seaweed consumption is much more popular than in the West. Seaweeds are considered to be highly nutritious, because typically they are low in fat, and have vitamins and minerals in amounts comparable or superior to terrestrial vegetables. "Alaria esculenta", in particular, is an excellent source of protein and iodine.