Hylocereus undatus (White-fleshed Pitahaya) is a species of 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 Dragonfruit. The native origin of the species has never been resolved.

Common names

• English: Pitahaya, Dragonfruit, Night blooming Cereus, Strawberry Pear, Belle of the Night, Conderella Plant
• Estonian: maasik-metskaktus
• French: fruit du dragon, cierge-lézard, poire de chardon
• German: Drachenfrucht, Distelbirne
• Hawaiian: panini-o-ka-puna-hou ("Punahou cactus") - a famous specimen still grows at Punahou School
• Portuguese: pitaia, cato-barse, cardo-ananaz, rainha da noite
• Spanish: pitahaya blanca (Colombia, Mexico, Venezuela); flor de caliz, pitajava (Puerto Rico); junco, junco tapatio, pitahaya orejona, reina de la noche, tasajo (Mexico)
• Swedish: skogskaktus, röd pitahaya
• Vietnamese: thanh long
• Thai: แก้วมังกร (kaeo mangkon)
• Malay: buah naga. pronounce:boo-ah naa-gaa
• Chinese: 火龙果 （huǒlóngguǒ）

Etymology

H. undatus is named for its undulate or wavy margins of the ribs.

History

Hylocereus undatus in bloom in Kona, Hawaii

There is a locally famous cacti hedge on a lava rock wall of the Punahou School in Honolulu, the hedge of Kapunahou.^[1]

In 1836, Mrs. Bingham planted the hedge^[2] of Hylocereus undatus, the famed cactus known in Hawaii as panini o kapunahou. Its exotic blossoms still bloom during the closing summer months on the Punahou walls. The hedge is on two sides of the school and about three hundred meters long.

From July to as late as October the hedge blooms and several times there is a wall of white flowers hundreds of yards long. Supposedly all the H. undatus in Hawaii came from the wall of Punahou School. People used to come in the evenings from all over the island to see them blooming and "borrow" some cuttings so that now they have this species all over the islands.

Hylocereus undatus overlooking Lanikai and Na Mokulua

Origin and habitat

Lithophytic or hemiepiphytic. Widely distributed through the tropics in cultivation, it originates in Makassar, Indonesia

Systematics

This species is closely related to H. ocamponis and H. escuintlensis.

Cultivation

An easily cultivated, fast growing epiphyte or xerophyte. Needs a compost containing plenty of humus and sufficient moisture in summer. Should not be kept under 10°C (50°F) in winter. Can be grown in semi-shade or full sun. Extra light in the early spring will stimulate budding. Flowers in summer or autumn.

Description

The Red Pitahaya at the Chiyai market, Taiwan

Stems scandent, creeping, sprawling or clambering, branching profusely, 4-7,5 (-10) m long or more, joints to 30–120 cm long or more, 10–12 cm thick; ribs generally 3; margins corneous in age, undulate; areoles 2 mm in diameter; internodes 1–4 cm; spines on adult branches 1-3, 2–4 mm long, acicular to subconic, grayish brown to black, spreading; epidermis deep green. Flowers 25–30 cm long, 15–17 cm wide, nocturnal, scented; pericarpel 2,5–5 cm long, ca 2,5 cm thick, bracteoles ovate, acute, to 2,5 (-4 ) cm long; receptacle ca 3 cm thick, bracteoles linear-lanceolate, 3–8 cm long; outer tepals lanceolate-linear to linear, acuminate, 10–15 cm long, 10–15 mm wide mucronate, greenish yellow or whitish, rarely tinged rose; inner tepals lanceolate to oblanceolate, to 10–15 cm long ca 40 mm wide at widest point, mucronate, entire, acute to acuminate, white; stamens 5–10 cm long, declinate, inserted in one continuous zone from throat to 35 mm above pericarpel, cream; style to 17,5-24.5 cm long, stout, 6–8 mm thick, cream, stigma lobes to 26, entire or sometimes cleft at apex, cream, ca 25 mm long. Nectar chambers 30 mm long. Fruit oblong to ovoid, to 6–12 cm long, 4–9 cm thick, red with large bracteoles, pulp white, edible; seeds black.

Cost

Dragonfruit cost about £1-2 each in the UK, PHP 90/kg in Indang, Philippines. In Taiwan they are about 45 NT each, and depending on season, can be found in Hong Kong for 10 HKD for 3 (3.33HKD/per).

See also

• Pitahaya
• List of culinary fruits

References

• Anderson, E. F. 2001. The cactus family. Timber Press, Portland, Oregon, USA.

Hylocereus undatus pitayas at a market stall in Taiwan.

A pitaya (pronounced /pɨˈtaɪ.ə/) or pitahaya (English pronunciation: /ˌpɪtəˈhaɪ.ə/) is the fruit of several cactus species, most importantly of the genus Hylocereus (sweet pitayas). These fruit are commonly known as dragon fruit – cf. Chinese huǒ lóng guǒ 火龍果/火龙果 "fire dragon fruit" and lóng zhū guǒ "dragon pearl fruit", or Vietnamese thanh long (green dragon). Other vernacular names are strawberry pear or nanettikafruit.

Native to Mexico and Central and South America, the vine-like epiphytic Hylocereus cacti are also cultivated in Asian countries such as Taiwan, Vietnam, Thailand, the Philippines, Sri Lanka and Malaysia. They are also found in Okinawa, Hawaii, Israel, northern Australia and southern China. Hylocereus blooms only at night; the large white fragrant flowers of the typical cactusflower shape are among those called "moonflower" or "Queen of the Night". Sweet pitayas have a creamy pulp and a delicate aroma.

If not otherwise stated, this article's content refers specifically to the pitayas of Hylocereus species, or "dragon fruit".

Stenocereus queretaroensis pitaya prepared for eating

Varieties

Selling dragon fruit juice in Thailand

Stenocereus fruit (sour pitayas) are of more local importance, being commonly eaten in the arid regions of the Americas. They are more sour and refreshing, with juicier flesh and a stronger taste, and are relished by hikers. The common Sour Pitaya or pitaya agria (S. gummosus)^[1] in the Sonoran Desert has been an important food source for Native American peoples. The Seri people of northwestern Mexico still harvest the highly appreciated fruit^[2], and call the plant ziix is ccapxl – "thing whose fruit is sour". The fruit of related species, such as S. queretaroensis and Dagger Cactus (S. griseus)^[3], are also locally important food. Somewhat confusingly, the Organ Pipe Cactus (S. thurberi) fruit (called ool by the Seris) is the pitahaya dulce ("sweet pitahaya") of its native lands, as dragon fruit are not grown there in numbers. It still has a more tart aroma than Hylocereus fruit, described as somewhat reminiscent of watermelon; it has some uses in folk medicine.

Fruits of some other columnar cacti (mainly Cereeae) are also called "pitayas" – for example those of the Peruvian Apple Cactus (Cereus repandus). very rare

Cultivation

Pitaya being grown commercially in southern Vietnam

Cereus repandus plants with Pitaya fruits in Sde Nitzan, Israel

After thorough cleaning of the seeds from the pulp of the fruit, the seeds may be stored when dried. Ideally, the fruit must be unblemished and overripe. Seeds grow well in a compost or potting soil mix - even as a potted indoor plant. Pitaya cacti usually germinate 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 10 lbs weight, one may see the plant flower. Pitaya cacti flower overnight, usually wilting by the morning. They rely on nocturnal creatures such as bats or moths for fertilization by other pitaya. Self-fertilization will not produce fruit. 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 especially 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. This is a much shorter route to reproduction. The plants handles up to 104^oF and very short periods of frost, but do 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.^[4][5][6]

Hylocereus has adapted to live in dry tropical climates with a moderate amount of rain. The dragon fruit sets on the cactus-like trees 30–50 days after flowering and can sometimes have 5-6 cycles of harvests per year. There are some farms in Vietnam that produce 30 tons of fruit per hectare every year.^[7]

Pests and diseases

Overwatering or excessive rainfall can cause the flowers to drop and fruit to rot. Birds can be a nuisance. The bacterium Xanthomonas campestris causes the stems to rot. Dothiorella fungi can cause brown spots on the fruit, but this is not common.

Fruit

Ripe dragon fruits, Vietnam

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 "dragon fruit".
• Hylocereus costaricensis (Costa Rica pitaya, often called H. polyrhizus) has red-skinned fruit with red flesh
• Hylocereus megalanthus (yellow pitaya, formerly in Selenicereus) has yellow-skinned fruit with white flesh.

Early imports from Colombia to Australia were designated Hylocereus ocampensis (supposedly red fruit) and Cereus triangularis (supposedly yellow fruit)^[8]. It is not quite certain to which species these taxa refer, though the latter is probably the red pitaya.

The fruit can weigh from 150 to 600 grams; some may reach one kilogram^[9]. To prepare a pitaya for consumption, the fruit is cut open to expose the flesh.^[9] The fruit's texture is sometimes likened to that of the kiwifruit due to the presence of black, crunchy seeds.^{[citation needed]} The flesh, which is eaten raw, is mildly sweet and low in calories.^{[citation needed]} Dragon fruit should not be used to accompany strong-tasting food, except to "clean the palate" between dishes.^{[citation needed]} The seeds are eaten together with the flesh, have a nutty taste and are rich in lipids^[10], but they are indigestible unless chewed. The fruit is also converted into juice or wine, or used to flavour other beverages. The flowers can be eaten or steeped as tea. The skin is not eaten, and in farm-grown fruit it may be polluted with pesticides.

Ingestion of significant amounts of red-fleshed dragon fruit (such as Costa Rica Pitaya) may result in pseudohematuria, a harmless reddish discoloration of the urine and faeces.^[11]

Gallery

Red Pitaya (Hylocereus undatus)	Red Pitayas for sale in Poland	Red Pitaya, cut open	Another opened Red Pitaya
Costa Rica Pitaya (Hylocereus costaricensis)	Flesh of Costa Rica Pitayas	Costa Rica Pitaya flower	Yellow Pitaya (Hylocereus megalanthus)
Pink dragonfruit

Nutritional information

Dragon fruit served in a buffet

Red Pitaya, ready to eat

The typical nutritional values per 100 g of raw pitaya (of which 55 g are edible) are as follows:

• Water 80-90 g
• Carbohydrates 9-14 g
• Protein 0.15-0.5 g
• Fat 0.1-0.6 g
• Fiber 0.3-0.9 g
• Ash 0.4-0.7 g
• Calories: 35-50

• Calcium 6–10 mg
• Iron 0.3-0.7 mg
• Phosphorus 16 – 36 mg

• Carotene (Vitamin A) traces
• Thiamine (Vitamin B₁) traces
• Riboflavin (Vitamin B₂) traces
• Niacin (Vitamin B₃) 0.2-0.45 mg
• Ascorbic acid (Vitamin C) 4–25 mg

They may change subject to cultivation conditions.

The fatty acid compositions of two pitaya seed oils were determined as follows:^[10]

• Particularly red-skinned pitayas are a good source of Vitamin C.^[12]
• Pitayas are rich in fiber and minerals, notably phosphorus and calcium. Red pitayas seem to be richer in the former, yellow ones in the latter.^[12]
• The seeds are rich in polyunsaturated fatty acids, and in particular Red Pitayas contain very little saturated fat.^[10]
• Pitahayas also contain significant quantities of phytoalbumin antioxidants, which prevent the formation of cancer-causing free radicals.^[13]
• In Taiwan, diabetics use the fruit as a food substitute for rice and as a source of dietary fibre.^[8]
• Pitaya supposedly increases excretion of heavy metal toxins and lowers cholesterol and blood pressure. Eaten regularly, it is credited with alleviating chronic respiratory tract ailments.^[8]

See also

• Opuntia, prickly pear cacti whose edible fruit are called "cactus figs"

Footnotes

References

• Agricultura Sensitiva (AS) [2008]: El cultivo de Pitaya y su posicionamiento en el mercado. Retrieved 2008-JAN-19.
• Ariffin, Abdul Azis; Bakar, Jamilah; Tan, Chin Ping; Rahman, Russly Abdul; Karim, Roselina & Loi, Chia Chun [2008]: Essential fatty acids of pitaya (dragon fruit) seed oil. Food Chemistry (in press) doi:10.1016/j.foodchem.2008.09.108
• Felger, Richard & Moser, Mary B. (1985): People of the desert and sea: ethnobotany of the Seri Indians. University of Arizona Press, Tucson
• Gasing Fruits (GF) [2008]: Nutrition facts about Pitaya. Retrieved 2007-JUN-16
• Greenhouse Girl (GG) (2006): Dragon Fruit. Version of 2006-JUL-17. Retrieved 2007-JUN-16.
• Jacobs, Dimitri (1999): Pitaya (Hylocereus undatus), a Potential New Crop for Australia. Australian New Crops Newsletter 11: 16.3. HTML fulltext
• Lauri, Bob (2000): Ocean Oasis Field Guide - Stenocereus gummosus. Retrieved 2007-OCT-01.
• Malaysian Medical Resources (MMR) (2008): Pseudohaematuria due to Dragonfruit ingestion. Retrieved 2008-FEB-24.
• Villalobos, Soraya; Vargas, Orlando & Melo, Sandra (2007): Uso, manejo y conservacion de "yosú", Stenocereus griseus (Cactaceae) en la Alta Guajira colombiana [Usage, Management and Conservation of yosú, Stenocereus griseus (Cactaceae), in the Upper Guajira, Colombia]. [Spanish with English abstract] Acta Biologica Colombiana 12(1): 99-112. PDF fulltext