Currently, only prickly pears are included in this genus of about 200 species distributed throughout most of the Americas. Chollas are now separated into the genus Cylindropuntia, which some still consider a subgenus of Opuntia. Austrocylindropuntia, Corynopuntia and Micropuntia are also often included in the present genus, but like Cylindropuntia they seem rather well distinct. Brasiliopuntia and Miqueliopuntia are closer relatives of Opuntia.
The most commonly culinary species is the Indian Fig Opuntia (O. ficus-indica). Most culinary uses of the term 'prickly pear' refer to this species. Prickly pears are also known as tuna, nopal or nopales, from the Nahuatl word nōpalli for the pads, or nostle, from the Nahuatl word nōchtli for the fruit; or paddle cactus (from the resemblance to the ball-and-paddle toy). They are native to Mexico.
Prickly pear cacti typically grow with flat, rounded platyclades that are armed with two kinds of spines; large, smooth, fixed spines and small, hairlike spines called glochids that easily penetrate skin and detach from the plant. Many types of prickly pears grow into dense, tangled structures.
Like all true cactus species, prickly pears are native only to the Western hemisphere; however, they have been introduced to other parts of the globe. Prickly pear species are found in abundance in Mexico, especially in the central and western regions. They are also found in the West of the United States, from arid regions in the Northwest, throughout the mid and lower elevations of the Rocky Mountains, and especially in the Southwest. Prickly pears are also the only types of cactus natively found to grow far east of the Great Plains states, as far northeast as Long Island, where it can be found in Northport.
Prickly pear species were introduced into Australia in the late 1800s, causing major ecological damage in the eastern states (see www.northwestweeds.nsw.gov.au). They are also found in the Mediterranean region of southern Europe, especially on the island nation of Malta where they grow on cactus found all over the island, and can be found in enormous numbers in parts of South Africa, where it was introduced from South America.
Opuntia are the most cold-tolerant of the lowland cacti, extending into western and southern Canada; one subspecies, Opuntia fragilis var. fragilis, has been found growing along the Beatton River in central British Columbia, southwest of Cecil Lake at 56° 17’ N latitude and 120° 39’ W longitude. Prickly Pears also give a fruit that is commonly eaten in Mexico, known as "Tuna", also used to make Aguas frescas. The fruit can be red, wine-red, green or yellow-orange.
Charles Darwin was the first to note that these cacti have thigmotactic anthers: when the anthers are touched, they curl over, depositing their pollen. This movement can be seen by gently poking the anthers of an open Opuntia flower. The same trait has evolved convergently in other cacti (e.g. Lophophora).
Chollas, now recognized to belong into a rather distinct genus Cylindropuntia, are distinguished by having cylindrical, rather than flattened, stem segments with the large barbed spines. The stem joints of several species, notably the jumping cholla (Cylindropuntia fulgida), are very brittle on young stems, readily breaking off when the barbed spines stick to clothing or animal skin as a method of vegetative reproduction. The barbed spines can remain embedded in the skin, causing significant discomfort and sometimes injury.
Prickly Pear branch growth
|Bud appears ►||Bud grows ►||Bud grows more►||Bud grows yet more►|
|Pad continues growth ►||Edible pad (tender) ►||Mature pad|
Opuntia and humans
The fruit of prickly pears, commonly called cactus figs, Indian fig or tuna, is edible, although it has to be peeled carefully to remove the small spines on the outer skin before consumption. If the outer layer is not properly removed, glochids can be ingested causing discomfort of the throat, lips, and tongue as the small spines are easily lodged in the skin. Native Americans like the Tequesta would roll the fruit around in suitable medium (e.g. grit) to "sand" off the glochids. Alternatively, rotating the fruit in the flame of a campfire or torch has been used to remove the glochids. Today, parthenocarpic (seedless) cultivars are also available.
Opuntia ficus-indica has been introduced to Europe and flourishes in areas with a suitable climate, such as the south of France, southern Italy, Sicily where they are referred to as fichi d'India or ficurinnia (Indian figs), along the Struma River in Bulgaria, in Southern Portugal and Madeira where they are called tabaibo, figo tuno or "Indian figs", and eastern and southern Spain as well as Gibraltar where they are known as chumbo or higo chumbo ("chumbo fig"). In Greece it grows in such places as Corfu and its figs are known as frangosyka (French figs) or pavlosyka (Paul's figs). The figs are also grown in Cyprus, where they are known as papoutsosyka or Babutsa (shoe figs). The prickly pear also grows widely on the islands of Malta where it is enjoyed by the Maltese as a typical summer fruit (known as bajtar tax-xewk, literally 'spiny figs') as well as being used to make the popular liqueur known as Bajtra. The prickly pear is so commonly found in the Maltese islands that it is often used as a dividing wall between many of Malta's characteristic terraced fields in place of the usual rubble walls. The prickly pear was introduced to Eritrea during the period of Italian colonisation between 1890 and 1940. It is locally known there as Beles and is abundant during the months of late summer and early autumn (late July through September). The Beles from the holy monastery of Bizen is said to be particularly sweet and juicy.
In Egypt, Saudi Arabia, Israel and other parts of the Middle East, prickly pears of the yellow and orange varieties are grown by the side of farms, beside railway tracks and other otherwise non-cultivable land. It is sold in summer by street vendors and is considered a nice refreshing fruit for that season.
Tungi is the local St. Helenian name for cactus pears. The plants (Indian Fig Opuntia) were originally brought to the island by the colonial ivory traders from East Africa in the 1850s. Tungi cactus now grows wild and organically in the dry coastal regions of the island. Three principal cultivars of tungi grow on the island: the 'English' with yellow fruit; the 'Madeira' with large red fruit; and the small firm 'Spiny Red'.
The young stem segments, usually called nopales, are also edible in most species of Opuntia. They are commonly used in Mexican cuisine in dishes such as huevos con nopales (eggs with nopal), or tacos de nopales. Nopales are also an important ingredient in New Mexican cuisine.
Most species of Opuntia contain a range of alkaloids in ample quantities, notably substituted phenethylamines. While the mere presence of such compounds has been confirmed in many species without further details, they have been studied more thoroughly in others. Identified compounds of medical significance include 3-methoxytyramine, candicine, hordenine, N-methyltyramine, and tyramine. The Sicilian prickly pear contains the betalain antioxidants betanin and indicaxanthin, with highest levels in their fruits.
The stem of certain Opuntia spp. can be used to treat type II diabetes, diarrhoea, and stomach ache. However, usefulness of Opuntia in treating diabetes is not at all resolved. Although some researchers have shown a blood glucose-lowering effect of O. streptacantha, another study of three other species of Opuntia (O. lasiacantha, O. velutina, and O. macrocentra) showed no such effect. Yet another study, on O. megacantha, raised concern about toxic effects on the kidney.
It may be that certain species are effective and useful in diabetes while others are not but this needs to be clarified with further research before recommending its use. Furthermore, when buying nopal in the market, it is impossible to know which species one is buying and therefore whether or not it is useful in treating diabetes.
Indian Fig Opuntia (and probably others) might have a reducing effect on alcohol hangover by inhibiting the production of inflammatory mediators. Studies have yielded differing results, with some studies witnessing significant reductions in nausea, dry mouth, and loss of appetite as well as less risk of a severe hangover, while others witnessing no compelling evidence for effects on alcohol hangover.
In Mexico and the Southwest, its pulp and juice have been used to treat a numerous amount of maladies such as wounds and inflammations of the digestive and urinary tracts.
As an intoxicant
Mexicans have used it for thousands of years to make Colonche, an alcoholic drink. At least two commercially important distilled spirits are produced from Opuntia fruit. In Malta, the pink herbal Bajtra Liqueur is made from Opuntia. A St. Helenian distillery produces the clear, more potent Tungi Spirit from Indian Fig Opuntia cv. 'English' and 'Madeira'.
Opuntia is also added sometimes to the entheogenic drink Ayahuasca. Psychoactive compounds and derivates thereof have been confirmed in some species. These include 3,4-DMPEA, 4-hydroxy-3,5-DMPEA, and mescaline.
In dye production
Dactylopius coccus is a scale insect, from which the cochineal dye is derived. D. coccus itself is native to tropical and subtropical South America and Mexico. This type of insect, a primarily sessile parasite, lives on cacti from the genus Opuntia, feeding on moisture and nutrients in the cactus sap. The insect produces carminic acid which deters predation by other insects. The carminic acid can be extracted from the insect's body and eggs to make the red dye.
Cochineal is primarily used as a red food colouring and for cosmetics. The cochineal dye was used by the Aztec and Maya peoples of Central and North America. Produced almost exclusively in Oaxaca, Mexico by indigenous producers, cochineal became Mexico's second most valued export after silver. The dyestuff was consumed throughout Europe and was so highly valued that its price was regularly quoted on the London and Amsterdam Commodity Exchanges.
In present times, the highest production of cochineal is by Peru, the Canary Islands and Chile. Current health concerns over artificial food additives have renewed the popularity of cochineal dyes, and the increased demand is making cultivation of the insect an attractive opportunity in other regions, such as in Mexico where cochineal production had declined again due to the scale insect having numerous natural enemies.
Apart from cochineal, the red dye betanin can be extracted from some Opuntia plants themselves.
The coat of arms of Mexico depicts a Mexican golden eagle, perched upon an Opuntia cactus, devouring a rattlesnake. According to the official history of Mexico, the coat of arms is inspired by an Aztec legend regarding the founding of Tenochtitlan. The Aztecs, then a nomadic tribe, were wandering throughout Mexico in search of a divine sign that would indicate the precise spot upon which they were to build their capital. Their god Huitzilopochtli had commanded them to find an eagle devouring a snake, perched atop a cactus that grew on a rock submerged in a lake. After two hundred years of wandering, they found the promised sign on a small island in the swampy Lake Texcoco. It was there they founded their new capital, Tenochtitlan. The cactus (Opuntia ficus-indica; Nahuatl: tenochtli), full of fruits, is the symbol for the island of Tenochtitlan.
The 1975–1988 version of the coat of arms of Malta also featured an opuntia.
In Palestine, the prickly pear cactus has been used for centuries both as a food source and a natural fence that keeps in livestock and marks the boundaries of family lands. They are incredibly resilient and often grow back. The cactus is called 'saber' in Arabic, which also means 'tenacity'. 
The cactus lends its name to a song by British Jazz/Classical group Portico Quartet.
Prickly pears (mostly Opuntia stricta) were imported into Australia in the 19th century for use as a natural agricultural fence and in an attempt to establish a cochineal dye industry. They quickly became a widespread invasive weed, rendering 40,000 km2 (15,000 sq mi) of farming land unproductive. The moth Cactoblastis cactorum from South America, whose larvae eat prickly pear, was introduced in 1925 and almost wiped out the population. This case is sometimes cited as an example of successful biological pest control. There is a monument to the Cactoblastis cactorum in Dalby, Queensland commemorating the eradication of the prickly pear in the region.
The same moth, introduced accidentally further north of its native range into southern North America, is causing serious damage to some native species in that area.
Other animals that eat Opuntia include the Prickly pear island snail and Cyclura rock iguanas. The fruit are relished by many aridland animals, chiefly birds, which thus help distribute the seeds. Opuntia pathogens include the sac fungus Colletotrichum coccodes and Sammons' Opuntia virus. The ant Crematogaster opuntiae and the spider Theridion opuntia are named for their association with prickly pear cacti.
- Opuntia aciculata
- Opuntia anacantha
- Opuntia atrispina
- Opuntia auberi
- Opuntia aurantiaca
- Opuntia basilaris – Beavertail cactus
- Opuntia boldinghii
- Opuntia chaffeyi
- Opuntia chlorotica – Pancake Prickly Pear; native to southwest USA and the Sonoran and Mojave deserts.
- Opuntia clavata
- Opuntia cochenillifera
- Opuntia comonduensis
- Opuntia compressa
- Opuntia curvospina
- Opuntia decumana
- Opuntia decumbens – Nopal de Culebra
- Opuntia dejecta
- Opuntia echios
- Opuntia echios var. gigantea – Galápagos prickly pear. Galápagos Islands.
- Opuntia elata
- Opuntia elatior Mill. – syn. O. bergeriana
- Opuntia engelmannii – Engelmann's Prickly Pear, Cow's-tongue Prickly Pear, Desert Prickly Pear, Discus Prickly Pear, Texas Prickly Pear, calico cactus
- Opuntia erinacea
- Opuntia exaltata
- Opuntia excelsa
- Opuntia ficus-barbarica