Gelidium is a genus of thalloid red algae comprising 124 species. Its members are known by a number of common names.[note 1] Specimens can reach around 2–40 cm (0.79–16 in) in size. Branching is irregular, or occurs in rows on either side of the main stem. Gelidium produces tetraspores. Many of the algae in this genus are used to make agar. Chaetangium is a synonym.
Gelidium species have been collected, pressed and maintained in herbaria and personal collections from the 1850s onwards since seaweed collecting became a popular pastime for the middle classes as well as scientists in Europe and North America. These numerous well-documented specimens can provide information beyond taxonomy.
SuhriaVittataThis name is currently regarded as a synonym of Gelidiumvittatum (Linnaeus) Kützing