Echinocactus genus consists of 6 species. Named after the ancient Greek word εχινος, meaning porcupine or spiny, because of their strong dense spines. It belongs to genera of "barrel" cactus, together with Ferocactus. Usually has heavy spination and relatively small flowers. The fruits are copiously woolly, and this is one major distinction between Echinocactus and Ferocactus.
The best known species is Echinocactus grusonii (the golden barrel) from Mexico, an easy-to-grow and widely cultivated plant. Though common as the houseplant, the golden barrel has become very rare in habitat.