Gelidium is a type of red algae from the Gelidiaceae family. This species of algae measures between 2 and 6 cm. It has a cartilaginous appearance of a purple color. It comprises 124 species, known by several common names and their size is generally between 2 and 40 cm. Their branching is irregular or in rows on either side of the main thallus. Gelidium produces tetraspores.