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.
Cylindropuntia is a genus of cacti, containing species commonly known as chollas, native to northern Mexico and the Southwestern United States. They are known for their barbed spines that tenaciously attach to skin, fur, and clothing. Stands of cholla are called cholla gardens. Individuals within these colonies often exhibit the same DNA, as they were formerly tubercles of an original plant.
Pereskiopsis is a genus of cactus in the subfamily Opuntioideae. Unlike typical cacti, it has persistent fleshy leaves. The genus name refers to its resemblance to the genus Pereskia. Most species are found in Mexico south through Guatemala to Honduras, with one species in Bolivia. The incorrect spelling Peireskiopsis has also been used.
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.
Opuntioideae is a subfamily of the cactus family, Cactaceae. It contains 15 genera divided into five tribes. The subfamily encompasses roughly 220–250 species, and is geographically distributed throughout the New World from Canada, to Argentina. Members of this subfamily have diverse habits, including small geophytes, hemispherical cushions, shrubs, trees, and columnar cacti consisting of indeterminate branches or determinate terete or spherical segments.
The Madrean Region is a floristic region within the Holarctic Kingdom in North America, as delineated by Armen Takhtajan and Robert F. Thorne. It occupies arid or semiarid areas in the southwestern United States and northwestern Mexico and is bordered by the Rocky Mountain Floristic Region and North American Atlantic Region of the Holarctic Kingdom in the north and in the east, Caribbean Region of the Neotropical Kingdom in the south.
Opuntia, commonly called the prickly pear cactus, is a genus of flowering plants in the cactus family Cactaceae, many known for their flavorful fruit and showy flowers. Prickly pear alone is more commonly used to refer exclusively to the fruit, but may also be used for the plant itself; in addition, other names given to the plant and its specific parts include tuna (fruit), sabra, nopal from the Nahuatl word nōpalli, nostle (fruit) from the Nahuatl word nōchtli, and paddle cactus. The genus is named for the Ancient Greek city of Opus, where, according to Theophrastus, an edible plant grew and could be propagated by rooting its leaves. The most common culinary species is the Indian fig opuntia (O. ficus-indica).
Opuntia robusta, the wheel cactus, nopal tapon, or camuesa, is a species of cactus in the family Cactaceae. It is native and endemic to central and northern Mexico to within 100 miles (160 km) of the Arizona and New Mexico borders where it grow from 5,000 to 10,000 feet on rocky slopes, open shrub lands, woodlands and mixed with other cactus and succulents.
Opuntia chlorotica is a species of plant in the family Cactaceae. It is a species of prickly pear native to the southwestern United States and northern Mexico. Its common names include pancake prickly pear, flapjack prickly pear and dollarjoint prickly pear.
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.
Prickly pears include a number of plant species that were introduced and have become invasive in Australia.
Opuntia polyacantha is a common species of cactus known by the common names plains pricklypear, starvation pricklypear,. and hairspine cactus, panhandle pricklypear. It is native to North America, where it is widespread in Western Canada, the Great Plains, the central and Western United States, and Chihuahua in northern Mexico. In 2018, a disjunct population was discovered in the Thousand Islands region of Ontario, Canada.
Dactylopius is a genus of insect in the superfamily Coccoidea, the scale insects. It is the only genus in the family Dactylopiidae. These insects are known commonly as cochineals, a name that also specifically refers to the best-known species, the cochineal. The cochineal is an insect of economic and historical importance as a main source of the red dye carmine. It has reportedly been used for this purpose in the Americas since the 10th century. Genus Dactylopius is also important because several species have been used as agents of biological pest control, and because several are known as invasive species.
Opuntia diploursina is a species in the family Cactaceae, that grows near and in Lake Mead National Recreation Area and extending northward across Nevada's Mormon Mesa into Utah.
Opuntia trichophora is a species of cactus in the genus Opuntia, more commonly known as prickly pears or nopal. O. trichophora is distributed throughout parts of New Mexico, Colorado, and Utah, and may have disjoint populations in Wyoming, southern Montana, and southern Idaho. Opuntia trichophora is a diploid (2n=22) but has sometimes been treated as a variety of Opuntia polyacantha a tetraploid (2n=44). O. trichophora tends to have longer spines than O. polycantha or O. macrorhiza.
Opuntia lindheimeri or Texas prickly pear is a species of cactus native to North America. It is native to Mexico and the United States, where its populations are primarily in Texas.
Opuntia arenaria was considered a variety of O. polyacantha by many botanists, and is still treated that way in the Flora of North America. However, O. arenaria is diploid and O. polyacantha is tetraploid. It was described by Engelmann in 1856.
