The 'original' carrageenan was Chondrus Crispus,a red seaweed found in the north Atlantic. Another name for this seaweed is 'Irish moss'; a name still used in the brewing industry. Chondrus crispusactually contains a mix of carrageenan types, the predominant ones being kappa and lambda. Today Newfoundland is one of the main sources of chondrus crispus but it is not a major source of carrageenan in world terms. Chondrus Crispus is wild harvested and not farmed. The only farmed Chondrus Crispus is used in the culinary market.
Gigartina is one of the major species used in the extraction of carrageenan. Gigartina is wild harvested in various forms including Gigartina Skottsbergii off the coast of Argentina and Chile, Gigartina Stellata from the coast of France. Gigartina is a mixed weed type. Unlike in some weed types Gigartina has the various carrageenan types actually mixed up along the same polymer chain in a 'hybrid' type of polymer. Iridaea is another type of South American weed found off the coast of Chile. Both of these weed types contain mixtures of kappa, iota and lambda carrageenan. Hybrid weed species are often preferred in some dairy applications.
Eucheuma is a pacific specie and comes in two major commercial forms, Eucheuma Cottonii andEucheuma Spinosum. Unlike the other weed types the Eucheuma species are relatively pure in the carrageenan type they contain. Cottonii is predominantly kappa carrageenan and Spinosum is largely iota carrageenan.This allows greater flexibility in formulation because you are not restricted to the ratios of kappa and iota that happen to occur in the native weedstock. The largest commercial source of Eucheuma is the Philippines where the weed is actually farmed rather than wild harvested. Other major sources include Indonesia and to a lesser extent Africa and the pacific islands.
Hypnea and furcellaran are other types of carrageenan that are seen occasionally. The classification of seaweeds is still a confused subject and many other names are also heard these names are used interchangeably in the industry. For example Eucheuma Cottonii is often referred to as Kappaphycus Alvarezei and although this may not be technically correct it is common practise.