Dragon fruit (Hylocereus undatus (Haw.)) or pitaya, have been grown in Vietnam for at least 100 years, following their introduction by the French (Mizrahi et al., 1997). Locally the fruit is known and sold as Thanh Long, or ‘Green Dragon’, a description associated with the green colour of the immature fruit, and the ‘dragon-like’ appearance of the ‘scales’ or bracts on the fruit surface. Native to Mexico and Central and South America, the vine-like epiphytic Hylocereus cacti are also cultivated in Southeast Asian countries such as Taiwan, Vietnam, the Philippines, and Malaysia. They are also found in Okinawa, Israel, northern Australia and southern China. Hylocereus blooms only at night; they have large white fragrant flowers of the typical cactusflower shape that are often called Moonflower or Queen of the Night. Sweet pitayas have a creamy pulp and a delicate aroma (en.wikipedia.org).
Sweet pitayas come in three types, all with leathery, slightly leafy skin:
Hylocereus undatus (Red Pitaya) has red-skinned fruit with white flesh. This is the most commonly-seen "dragonfruit".
Hylocereus costaricensis (Costa Rica Pitaya, sometimes called H. polyrhizus) has red-skinned fruit with red flesh