A cactus is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 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. Although some species live in quite humid environments, most cacti live in habitats subject to at least some drought. Many live in extremely dry environments, even being found in 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. Cacti are native to the Americas, ranging from Patagonia in the south to parts of western Canada in the north—except for Rhipsalis baccifera, which also grows in Africa and Sri Lanka.
Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation, to provide energy and nutrients for regrowth during the next growing season, and as a means of asexual reproduction. Stem tubers form thickened rhizomes or stolons ; well known species with stem tubers include the potato and yam. Some writers also treat modified lateral roots under the definition; these are found in sweet potatoes, cassava, and dahlias.
Pachypodium is a genus of succulent spine-bearing trees and shrubs, native to Madagascar and Africa. It belongs to the family Apocynaceae.
A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water. Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have an underground storage organ are called geophytes in the Raunkiær plant life-form classification system. Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions.
Schlumbergera is a small genus of cacti with six to nine species found in the coastal mountains of south-eastern Brazil. These plants grow on trees or rocks in habitats that are generally shady with high humidity, and can be quite different in appearance from their desert-dwelling cousins. Most species of Schlumbergera have stems which resemble leaf-like pads joined one to the other and flowers which appear from areoles at the joints and tips of the stems. Two species have cylindrical stems more similar to other cacti. Recent phylogenetic studies using DNA have led to three species of the related genus Hatiora being transferred into Schlumbergera, though this change is not universally accepted.
Arrojadoa is a genus of cacti, comprising 6 species and several varieties. It is named after the Brazilian botanist Miguel Arrojado Lisboa (1872–1932) who was superintendent of the Brazilian Railways at the time that Britton and Rose described the genus in 1920. The genus occurs only in northern Brazil and is found at rocky places, under shrubs, which support their frail stalk. They are subtropical plants, with very little frost tolerance.
Jasminocereus is a genus of cacti with only one species, Jasminocereus thouarsii, endemic to the Galápagos Islands, territorially a part of Ecuador. In English it is often called the candelabra cactus. At maturity it has a branched, treelike habit, and may be up to 7 m (23 ft) tall. The stems are made up of individual sections with constrictions between them. Its creamy white to greenish flowers open at night and are followed by greenish to reddish fruits.
Ariocarpus is a small genus of succulent, subtropical plants of the family Cactaceae.
Sclerocactus is a genus of cacti. It comprises about 15 species, the exact number depending on the authority. These species are very xerophytic. They are sometimes called 'fishhook cactus' or 'little barrels.'
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.
Grusonia is a genus of opuntioid cacti, originating from the North American Deserts in Southwest United States and northern Mexico, including Baja California. Authors differ on precise boundaries of the genus, which has been included in Cylindropuntia. Corynopuntia, also known as club chollas, is now a synonym, with the genus originally being described by Knuth in 1935. Molecular phylogenetic studies suggest that it should be included in Grusonia, a view accepted by Plants of the World Online as of June 2021.
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.
Chaerophyllum bulbosum is a species of flowering plant from the carrot family and known by several common names, including turnip-rooted chervil, tuberous-rooted chervil, bulbous chervil, and parsnip chervil. It is native to Europe and Western Asia. It was a popular vegetable in the 19th century.
Echinopsis pachanoi —known as San Pedro cactus—is a fast-growing columnar cactus native to the Andes Mountains at 2,000–3,000 m (6,600–9,800 ft) in altitude. It is found in Argentina, Bolivia, Colombia, Chile, Ecuador and Peru, and it is cultivated in other parts of the world. Uses for it include traditional medicine and traditional veterinary medicine, and it is widely grown as an ornamental cactus. It has been used for healing and religious divination in the Andes Mountains region for over 3,000 years. It is sometimes confused with its close relative Echinopsis peruviana.
The cactus wren is a species of wren endemic to the deserts of the southwestern United States and northern and central Mexico. It is the state bird of Arizona, and the largest wren in the United States. Its plumage is brown, with black and white spots as markings. It has a distinctive white eyebrow that sweeps to the nape of the neck. The chest is white, whereas the underparts are cinnamon-buff colored. Both sexes appear similar. The tail, as well as flight feathers, are barred in black and white. Their song is a loud raspy chirrup; akin in the description of some ornithologists to the sound of a car engine that will not start. It is well-adapted to its native desert environment, and the birds can meet their water needs from their diet which consists chiefly of insects, but also of some plant matter. The cactus wren is a poor flier and generally forages for food on the ground. Ornithologists generally recognize seven subspecies, with the exact taxonomy under dispute.
The saguaro is a tree-like cactus species in the monotypic genus Carnegiea that can grow to be over 12 meters tall. It is native to the Sonoran Desert in Arizona, the Mexican state of Sonora, and the Whipple Mountains and Imperial County areas of California. The saguaro blossom is the state wildflower of Arizona. Its scientific name is given in honor of Andrew Carnegie. In 1994, Saguaro National Park, near Tucson, Arizona, was designated to help protect this species and its habitat.
Ornamental bulbous plants, often called ornamental bulbs or just bulbs in gardening and horticulture, are herbaceous perennials grown for ornamental purposes, which have underground or near ground storage organs. Botanists distinguish between true bulbs, corms, rhizomes, tubers and tuberous roots, any of which may be termed "bulbs" in horticulture. Bulb species usually lose their upper parts during adverse conditions such as summer drought and heat or winter cold. The bulb's storage organs contain moisture and nutrients that are used to survive these adverse conditions in a dormant state. When conditions become favourable the reserves sustain a new growth cycle. In addition, bulbs permit vegetative or asexual multiplication in these species. Ornamental bulbs are used in parks and gardens and as cut flowers.
Grusonia parishii 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.
Epiphyllum hybrids, epiphyllums, epicacti, or just epis, also known as orchid cacti, which are widely grown for their flowers, are artificial hybrids of species within the group of cacti placed in the tribe Hylocereeae. In spite of the common name, epiphyllum hybrids mainly involve Disocactus species instead of Epiphyllum species, though Selenicereus grandiflorus and some unconfirmed Epiphyllum species were reportedly used for hybridization. Other sources include Pseudorhipsalis in the parentage of the group.
Hatiora salicornioides, the bottle cactus, dancing-bones, drunkard's-dream, or spice cactus, is a species of flowering plant in the cactus family. A member of the tribe Rhipsalideae, it often grows as an epiphyte. It is native to eastern Brazil. It is sometimes grown both indoors and outdoors as an ornamental.
