A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1,750 known species of the order Caryophyllales. The word cactus derives, through Latin, from the Ancient Greek word κάκτος (káktos), a name originally used by Theophrastus for a spiny plant whose identity is now not certain. Cacti occur in a wide range of shapes and sizes. They are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north, with the exception of Rhipsalis baccifera, which is also found in Africa and Sri Lanka. Cacti are adapted to live in very dry environments, including the Atacama Desert, one of the driest places on Earth. Because of this, cacti show many adaptations to conserve water. For example, almost all cacti are succulents, meaning they have thickened, fleshy parts adapted to store water. Unlike many other succulents, the stem is the only part of most cacti where this vital process takes place. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing air flow close to the cactus and providing some shade. In the absence of true leaves, cacti's enlarged stems carry out photosynthesis.
Opuntia ficus-indica, the Indian fig opuntia, fig opuntia, or prickly pear, is a species of cactus that has long been a domesticated crop plant grown in agricultural economies throughout arid and semiarid parts of the world. O. ficus-indica is the most widespread and most commercially important cactus. It is grown primarily as a fruit crop, and also for the vegetable nopales and other uses. Cacti are good crops for dry areas because they efficiently convert water into biomass. O. ficus-indica, as the most widespread of the long-domesticated cactuses, is as economically important as maize and blue agave in Mexico. Opuntia species hybridize easily, but the wild origin of O. ficus-indica is likely to have been in central Mexico, where its closest genetic relatives are found.
Pediocactus is a genus of cacti native to the Western United States. The genus comprises between 6 and 11 species, depending upon the authority. Species of this genus are referred to as hedgehog cacti, though that name is also applied to plants from the genera Echinocereus and Echinopsis. Species may also be referred to as pincushion cacti, a common name which is also applied to other genera.
Brasiliopuntia is a genus in the cactus family, Cactaceae. It contains only one species, Brasiliopuntia brasiliensis.
Echinocereus engelmannii, the strawberry hedgehog cactus or Engelmann's hedgehog cactus, is a cactus commonly found in desert areas of the southwestern United States and the adjacent areas of Mexico, including the states of California, Nevada, Utah, Arizona, Baja California and Sonora.
Ariocarpus agavoides is a species of cactus. It is endemic to Mexico. It grows in dry shrubland in rocky calcareous substrates. Some taxonomists place it in a separate genus as Neogomezia agavoides. The locals use the slime from the roots of the plants as glue to repair pottery. The sweet-tasting warts are eaten and often added to salads
Opuntia monacantha, commonly known as drooping prickly pear, cochineal prickly pear, or Barbary fig, is a species of plant in the family Cactaceae native to South America.
Cylindropuntia echinocarpa is a species of cactus known by the common names silver cholla, golden cholla, and Wiggins' cholla. It was formerly named Opuntia echinocarpa.
Coryphantha ramillosa is a rare species of cactus known by the common names bunched cory cactus and whiskerbush. It is native to the border region between Texas in the United States and Coahuila in Mexico. Because it was believed to be rare and threatened by a number of processes, it was federally listed as a threatened species of the United States in 1979.
Pediocactus bradyi is a very rare species of cactus known by the common names Brady's pincushion cactus, Brady's hedgehog cactus, and Marble Canyon cactus. It is endemic to Arizona in the US, where it is restricted to Marble Canyon in Coconino County, though its exact distribution is not generally advertised due to poaching concerns. It is limited to a specific type of soil, it has a small distribution, and the species is threatened by a number of human activities. This has been a federally listed endangered species of the United States since 1979.
Pediocactus peeblesianus is a rare species of cactus known by the common names Navajo pincushion cactus. It is endemic to the state of Arizona in the United States. The species is named after the Arizona botanist Robert Hibbs Peebles.
Opuntia macrocentra, the long-spined purplish prickly pear or purple pricklypear, is a cactus found in the lower Southwestern United States and Northwestern Mexico. A member of the prickly pear genus, this species of Opuntia is most notable as one of a few cacti that produce a purple pigmentation in the stem. Other common names for this plant include black-spined pricklypear, long-spine prickly pear, purple pricklypear, and redeye prickly pear.
Echinocereus rigidissimus, commonly known as the Arizona rainbow cactus or rainbow hedgehog cactus, is a solitary-growing cactus that rarely branches or offsets with age.
Opuntia tortispina is a species of flowering plant in the family Cactaceae, native to the central United States. It was first described in 1856.
Opuntia rufida is a species of prickly pear cactus native to southwestern Texas and northern Mexico, where it grows on rocky slopes. The species makes up for its total lack of spines with a profusion of red-brown glochids. The common name blind prickly pear or cow blinder comes from the fact that the glochids may be carried away by the wind and blind animals.
Opuntia hyptiacantha is a species of plant that belongs to the family Cactaceae. They can be found in Mexico within Durango, Aguascalientes, Zacatecas, San Luis Potosí, Jalisco, Guanajuato, Querétaro, and the State of Mexico.
Opuntia sulpurea falls under the Opuntia, or prickly pear, genus within the family Cactaceae named such because of their round shape, green color, and long thick spines. Opuntia sulphurea is the widest spread of the Opuntia that can be found in and around Argentina, occupying mostly arid areas of the region from the plains in the Western portion of Argentina up to much higher altitudes on the Eastern side of the Andes mountain range. As a result of its ability to survive in such a diverse array of environments there are several subspecies of O. sulphurea that are identifiable based on the number of spine per areole, for example. A commonality across the three is a bright yellow flower, often considered to be the color of sulfur, from which the species name is derived. As with several other species of Opuntia, these prickly pears tend to grow in groups, forming clumps that can reach one to two meters in diameter, but while other species within the genus grow upwards as well O. sulphurea tend to stay low to the ground. As a result of its tendency to grow in dry, arid, and rocky areas this cactus has evolved to be very resilient, not even suffering from the effects of agriculture, i.e. cattle grazing, on lower altitude subpopulations.
Opuntia setispina is a species of cactus found in the Sierra Madre Occidental in Chihuahua, Sonora, and Durango in Mexico. The name O. setispina has been listed as a synonym under Opuntia macrorhiza and Opuntia pottsii, but shows no close relationship to either species. It is more of a woody shrubby, often somewhat tree-like species, growing up to approximately 1 meter tall and wide. It is morphologically similar to Opuntia chlorotica, Opuntia santa-rita, and Opuntia gosseliniana.
Opuntia caracassana is a species from the genus Opuntia. The species was originally described by Joseph zu Salm-Reifferscheidt-Dyck in 1850.
Dactylopius opuntiae, also known as the prickly pear cochineal, is a species of scale insect in the family Dactylopiidae.
