Selenicereus undatus, the white-fleshed pitahaya, is a species of the genus Selenicereus (formerly Hylocereus) in the family Cactaceae and is the most cultivated species in the genus. It is used both as an ornamental vine and as a fruit crop - the pitahaya or dragon fruit.
Like all true cacti, the genus originates in the Americas, but the precise native origin of the species S. undatus is uncertain and never been resolved.