Pitaya
A pitaya () or pitahaya () is the fruit of several different cactus species indigenous to the Americas. Pitaya usually refers to fruit of the genus "Stenocereus", while pitahaya or dragon fruit refers to fruit of the genus "Selenicereus" (formerly "Hylocereus"), both in the family Cactaceae. Dragon fruit is cultivated in Mexico, South Asia, Southeast Asia, East Asia, the United States, the Caribbean, Australia, Mesoamerica and throughout tropical and subtropical regions of the world. Vernacular names. These fruits are commonly known in English as "dragon fruit", a name used since 1963, apparently resulting from the leather-like skin and prominent scaly  spikes on the fruit exterior. The names "pitahaya" and "pitaya" derive from Mexico, and "pitaya roja" in Central America and northern South America, possibly relating to pitahaya for names of tall cacti species with flowering fruit. The fruit may also be known as a "strawberry pear". Geography. Pitahaya or dragon fruit is native to southern Mexico and Central America. The dragon fruit is cultivated in East Asia, South Asia, Southeast Asia, the United States, the Caribbean, Australia, and throughout tropical and subtropical regions of the world. Varieties. Section::::"Stenocereus". "Stenocereus" fruit (sour pitayas) are a variety that is commonly eaten in  the arid regions of the Americas. They are more sour and refreshing, with juicier flesh and a stronger taste. The sour pitaya or "pitaya agria" ("S. gummosus") in the Sonoran Desert has been an important food source for indigenous peoples of the Americas. The Seri people of northwestern Mexico still harvest the fruit, and call the plant "ziix is ccapxl" "thing whose fruit is sour". The fruit of related species, such as "S. queretaroensis" and the dagger cactus ("S. griseus"), are also locally important foods. The fruit of the organ pipe cactus ("S. thurberi", called "ool" by the Seris) is  the "pitaya dulce" "sweet pitaya". It has a more tart aroma than "Selenicereus" fruit, described as somewhat reminiscent of watermelon. Dragon fruit "Selenicereus". Sweet pitayas come in three types, all with leathery, slightly leafy skin: The fruit normally weighs from ; some may reach . Early imports from Colombia to Australia were designated ""Hylocereus ocampensis"" (or ""Cereus repandus"", the red fruit) and ""Cereus triangularis"" (supposedly, the yellow fruit). It is not quite certain to which species these taxa refer. Cultivation. After a thorough cleaning of the seeds from the pulp of the fruit, the seeds may be stored when dried. The ideal  fruit is unblemished and overripe. Seeds grow well in a compost or potting soil mix – even as a potted indoor plant. Pitaya cacti usually germinate after between 11 and 14 days after shallow planting. As they are cacti, overwatering is a concern for home growers. As their growth continues, these climbing plants will find something to climb on, which can involve putting aerial roots down from the branches in addition to the basal roots. Once the plant reaches a mature in weight, the plant may flower. Commercial plantings can be done at high density with between . Plants can take up  to 60 months/260 weeks to come into full commercial production, at which stage yields of can be expected. Pitaya flowers bloom overnight and usually wilt by the evening. They rely on nocturnal pollinators such as bats or moths for fertilization. Self-fertilization will not produce fruit in some species, and while cross-breeding has resulted in several "self-fertile" varieties, cross-pollinating with a second, genetically distinct plant of the same species generally increases fruit set and quality. This limits the capability of home growers to produce the fruit. However, the plants can flower between three and six times in  a year depending on growing conditions. Like other cacti, if a healthy piece of the stem is broken off, it may take root in soil and become its own plant. The plants can endure temperatures up to and very short periods of frost, but will not survive long exposure to freezing temperatures. The cacti thrive most in USDA zones 10–11, but may survive outdoors in zone 9a or 9b. "Selenicereus" has adapted to live in dry tropical climates with a moderate amount of rain. In numerous regions, it has escaped cultivation to become a weed and is classified as an  invasive weed in some countries. Pests and diseases. Stems and fruits are susceptible to several diseases caused by fungi, bacteria, a nematode, and a virus. Overwatering or excessive rainfall can cause the flowers to drop and fruit to rot. The bacterium "Xanthomonas campestris" causes the stems to rot. "Dothiorella" fungi can cause brown spots on the fruit. Other fungi known to infect pitaya include "Botryosphaeria dothidea", "Colletotrichum gloeosporioides" and "Bipolaris cactivora". As food. The fruit's texture is sometimes likened to that of the kiwifruit because of its black, crunchy seeds. The seed oil contains the fatty acids linoleic acid  and linolenic acid. Dragon fruit is used to flavor and color juices and alcoholic beverages, such as "Dragon's Blood Punch" and the "Dragotini". The flowers can be eaten or steeped as tea. The red and purple colors of some "Selenicereus" fruits are due to betacyanins, a family of pigments that includes betanin, the same substance that gives beets, Swiss chard, and amaranth their red color. Nutrients. As the nutrient content of raw pitaya has not been thoroughly analyzed or published as of 2019, the USDA FoodData Central database reports one limited product label entry from a manufacturer of a  branded product, showing that a reference serving of dried pitaya provides of food energy, 82% carbohydrates, 4% protein, and 11% of the Daily Value each for vitamin C and calcium (see USDA link in table). Seed oils. The fatty acid compositions of two pitaya seed oils were determined as follows: