Native to Central and South America, dragon fruit are part of the cactaceae family. Dragon fruit is now grown commercially the world over. There are four different species of dragon fruit, but a plethora of hybrids within the four species are available. Hylocereus dragon fruit are made up of three different species, and Selenicereus has just one. Generally, it is easiest if you divide dragon fruit varieties up by color; white, pink or red flesh and white or yellow skin.
White Flesh/Pink Skin
Dragon fruit that has white flesh and pink skin or rind is the most common variety of the fruit. This type is called Hylocereus Undatus, and its flesh is not as sweet as dragon fruit with red or pink flesh. This variety may be sold under the name Alice, Cosmic Charlie, David Bowe, Guyute, Harpua, L.A. Woman, Neitzel, Seoul Kitchen, Thompson and Vietnamese Jaina.
Red or Pink Flesh/Pink Skin
Dragon fruit that has a pink skin or rind and flesh that is colored rather than white, is called Hylocereus Polyrhizus. This variety of dragon fruit is sweeter in taste than the white flesh variety and often larger in size. This variety may be sold under the name Bloody Mary, Red Jania, Voodoo Child and Zamorano.
White Flesh/Yellow Skin
The yellow skin/white flesh variety of dragon fruit tends to be both the smallest and the sweetest variety. This variety is called Selenicereus megalanthus,and is grown primarily in South America. It's not produced on the mass scale that other varieties are. This is sold only as yellow dragon fruit.