Pitaya usually refers to fruit of the genus Stenocereus, while pitahaya or dragon fruit refers to fruit of the genus Selenicereus, both in the family Cactaceae. The common name in English – dragon fruit – derives from the leather-like skin and scaly spikes on the fruit exterior. Depending on the variety, pitaya fruits may have sweet- or sour-tasting flesh that can be red, white, or yellow in color. The majority of the fruit by weight is water (87g out of 100g). One serving of 100-gram (3+1⁄2-ounce) provides 240 kilojoules (57 kilocalories) of food energy.