Eulychnia is a genus of candelabriform or arborescent cacti, comprising of about 9 species. These desert cacti can survive under very hot conditions where temperatures can reach up to 50 degrees Celsius. Furthermore, this breed of cacti can also survive in some of the driest places in the world such as the Atacama Desert, the driest desert in the world.

Eulychnia acida is a large tree-like cactus growing as tall as 4 meters. It is native to the coastal deserts of Chile and Peru. Its long central spines can grow to 20cm long. Flowers are borne near the stem tips in summer; they remain open day and night. The edible fruit is very juicy and acidic in taste. A souvenir item found in tourist shops around the world is often made from Eulychnia acida. Rainsticks are traditionally made in Chile from the dried skeletons of the stems of the cactus. A length of stem is cut and cleaned. Spines from the cactus are then pushed through the wall of the hollow stem. Course sand is added and the stem is sealed. When turned from end to end, a sound reminiscent of rain is produced as the sand falls over the spines inside the hollow stem.