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.
Monostroma
Monostroma is a genus of marine green algae (seaweed) in the family Monostromataceae. As the name suggests, algae of this genus are monostromatic (single cell layered). "Monostroma kuroshiense", an algae of this genus, is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. "Monostroma" oligosaccharides with degree of polymerization 6 prepared by agarase digestion from "Monostroma nitidum" polysaccharides have been shown to be an effective prophylactic agent during "in vitro" and "in vivo" tests against Japanese encephalitis viral infection. The sulfated oligosaccharides from "Monostroma" seem to be promising candidates for further development as antiviral agents. The genus "Monostroma" is the most widely cultivated genus among green seaweeds.