Eucheuma is a genus of thalloid alga comprising 24 species. Its members are known by a number of common names. Specimens can reach around 50 cm in size. The thalli take a crustose form. The medulla has a filamentous construction. Similar to Kappaphycus but with spiny branches. Thalli may reach several kg. in weight. Turgid and brittle. Branching not truly opposite. Colour ranges light tan to dark red, green or brown. Natural populations tend to grow scattered among or near soft and hard corals in tropical reef areas. “Cottonii of commerce” is cultivated. Euchema Cotoni also can be used for base material of cerageenan powder.