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.
Pereskia is a small genus of about four species of cacti that do not look much like other types of cacti, having substantial leaves and non-succulent stems. The genus is named after Nicolas-Claude Fabri de Peiresc, a 16th-century French botanist. The genus was more widely circumscribed until molecular phylogenetic studies showed that it was paraphyletic. The majority of species have since been transferred to Leuenbergeria and Rhodocactus. Although Pereskia does not resemble other cacti in its overall morphology, close examination shows spines developing from areoles, and the distinctive floral cup of the cactus family.
Cylindropuntia imbricata, the cane cholla, is a cactus found in the Southwestern United States and northern Mexico, including some cooler regions in comparison to many other cacti. It occurs primarily in the arid regions of the Southwestern United States in the states of Kansas, Oklahoma, Texas, New Mexico, Arizona, Colorado, and Nevada. It is often conspicuous because of its shrubby or even tree-like size, its silhouette, and its long-lasting yellowish fruits.
In 1984, the International Organization for Succulent Plant Study set up a working party, now called the International Cactaceae Systematics Group, to produce a consensus classification of the cactus family, down to the level of genus. Their classification has been used as the basis for systems published since the mid-1990s. Treatments in the 21st century have generally divided the family into around 125–130 genera and 1,400–1,500 species, which are then arranged in a number of tribes and subfamilies. However, subsequent molecular phylogenetic studies have shown that a very high proportion of the higher taxa are not monophyletic, i.e. they do not contain all of the descendants of a common ancestor. As of March 2017, the internal classification of the family Cactaceae remained uncertain and subject to change. A classification incorporating many of the insights from the molecular studies was produced by Nyffeler and Eggli in 2010.
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.
Grusonia pulchella (Engelm.) H.Rob., also known as sagebrush cholla, is a tuberous species of opuntioid cactus from the Mojave Desert of central Nevada, eastern California, northwestern Arizona and western Utah in the United States. Grusonia pulchella has at various times been included in Opuntia or placed in a separate genus Micropuntia.
Rhodocactus is a genus of flowering plant in the cactus family Cactaceae, native to central South America. Unlike most species of cacti, Rhodocactus has persistent leaves and a fully tree-like habit. The genus was sunk into a broadly circumscribed Pereskia, but molecular phylogenetic studies from 2005 onwards showed that with this circumscription Pereskia was paraphyletic, and in 2016, Rhodocactus was restored for southern South American species.
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.
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.
Grusonia parishiorum is a species of cactus known by the common names matted cholla and Parish club cholla. It is native to the Mojave and Sonoran Deserts of California and Arizona.
Cylindropuntia californica is a species of cholla cactus known by the common name snake cholla. It is primarily found in Baja California, Mexico and the southernmost part of California in the United States. It is characterized by a short, decumbent habit, yellow-green flowers, elongated stems, and short spines. It is mostly found in coastal sage scrub and coastal chaparral habitats, but two varieties in Baja California can be found in foothills and deserts. In California, variety californica is regarded as a rare and threatened plant, with a California Native Plant Society listing of 1B.1, in part due to its limited number of occurrences and threats from development. It formerly was considered to have a larger range due to the inclusion of Cylindropuntia bernardina within it as the variety parkeri.
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.
Leuenbergeria is a genus of flowering plant in the family Cactaceae, mostly native around the Caribbean. Unlike most cacti, it has persistent leaves and develops bark on its stems early in its growth. The genus was created in 2012 by Joël Lodé. Before the creation of Leuenbergeria as a genus, the species within it were included in a broadly circumscribed genus, Pereskia. Leuenbergeria is the only genus in the subfamily Leuenbergerioideae.
Cylindropuntia molesta is a cactus species that is endemic to Baja California state in Mexico.
Cylindropuntia bernardina is a species of cholla cactus commonly known as the cane cholla or valley cholla, native to California and northwestern Baja California. It is an erect cholla that grows up to 2–3 meters tall, and occurs primarily in the foothills of the Transverse and Peninsular Ranges, parts of the Sonoran Desert, and in the Coast Ranges with a few populations around the Cuyama River. It was formerly placed as the variety parkeri of Cylindropuntia californica until it was renamed to C. bernardina. It is more closely related to Cylindropuntia ganderi than to C. californica.
Opuntia tehuacana, commonly known as the Tehuacán prickly pear, is a species of prickly pear cactus in the family Cactaceae. It was described by Salvador Arias Montez and Susana Gama López in 1997, who were both Mexican botanists. The species was named for the town of Tehuacán, Mexico, which is near the center of the species range.
Opuntia austrina, also known as the Florida prickly pear, is a prickly pear cactus species that is endemic to Florida in the United States.
