Selenicereus, or moonlight cacti, is an epiphytic, lithophytic, and terrestrial cactus genus found in Mexico, Central America, the Caribbean and northern South America.
The generic name is derived from Selene, the Greek moon goddess, and cereus, meaning "candle" in Latin, referring to the nocturnal flowers. The term nightblooming cereus is sometimes used here, but this is also used for many night blooming cacti, including Epiphyllum, Hylocereus and Peniocereus. Selenicereus wercklei is native to Costa Rica this species was named after the German botanist Carl Wercklé (1860-1924).