Chondrus

Chondrus is a genus of red algae (Rhodophyta) in the family Gigartinaceae. It comprises several species, the best known of which is Chondrus crispus, commonly called Irish moss or carrageen moss. It is native to cold-temperate waters of the North Atlantic and adjacent seas.

Members of Chondrus form small to medium, flat, cartilaginous, branched thalli that range in color from dark red to purplish. Thalli are often bushy and may appear lobed or fan-shaped, growing on rocky substrates in shallow subtidal and upper intertidal zones.

Like many red algae, Chondrus exhibits a complex life cycle with alternating generations, including diploid tetrasporophyte and haploid gametophytes, and a carposporophyte stage on the female gametophyte. This triphasic life cycle contributes to genetic diversity and ecological resilience.

Chondrus crispus is the primary source of carrageenan, a sulfated polysaccharide used as a gelling and thickening agent in foods, cosmetics, and other industrial applications. Historically, edible preparations of Irish moss were used in various cuisines and traditional remedies, providing a practical example of seaweed utility.

The genus name derives from Greek chondros, meaning cartilage, reflecting the tough, cartilaginous texture of the thalli. Chondrus species continue to be studied for their ecological roles on rocky shores and for the quality and properties of carrageenan extracted from their cell walls.