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 κάκτος, kaktos, 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. Cacti show many adaptations to conserve water. 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 leaves, 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.
Epithelantha is a genus of cactus that is native to north-eastern Mexico, and the south-western United States from western Texas to Arizona. There are eight species recognised in the genus Epithelantha. The name Epithelantha refers to the flower position near the apex of the tubercles.
Thelocactus is a genus of flowering plants in the cactus family Cactaceae. Members of the genus are native to the arid lands of Central and Northern Mexico.
Dasylirion wheeleri is a species of flowering plant in the asparagus family Asparagaceae, native to arid environments of northern Mexico, in Chihuahua and Sonora and in the southwestern United States, in the Sonoran Desert in Arizona, and also in New Mexico and Texas.
Selenicereus hamatus is a species of Cactaceae and produces one of the largest flowers in the family. It is a cultivated ornamental vine. The species is native to Mexico.
Selenicereus spinulosus is a cactus species native to eastern Mexico and, possibly, the lower Rio Grande Valley of Texas in the United States. Common names include vine-like moonlight cactus and spiny moon cereus. Its specific name, spinulosus, means "with small spines" in Latin.
Vachellia constricta, also known commonly as the whitethorn acacia, is a shrub native to Mexico and the Southwestern United States, with a disjunct eastern population in Virginia and Maryland.
Epiphyllum pumilum is a cactus species native to Mexico and Guatemala. The species is commonly grown as an ornamental for its beautiful, fragrant flowers in the summer.
Gymnocalycium saglionis, the giant chin cactus, is a globular cactus species endemic to northwest Argentina.
Selenicereus grandiflorus is a cactus species originating from the Antilles, Mexico and Central America. The species is commonly referred to as queen of the night, night-blooming cereus, large-flowered cactus, sweet-scented cactus or vanilla cactus. The true species is extremely rare in cultivation. Most of the plants under this name belong to other species or hybrids. It is often confused with the genus Epiphyllum.
Mammillaria elongata, the gold lace cactus or ladyfinger cactus, is a species of flowering plant in the family Cactaceae, native to central Mexico. Growing to 15 cm (6 in) tall by 30 cm (12 in) wide, it consists of densely packed clusters of elongated oval stems, covered in harmless yellow or brown spines, and in spring producing white or yellow flowers. It is among the commonest and most variable of its genus in nature, and is a popular subject for cultivation. It has gained the Royal Horticultural Society's Award of Garden Merit.
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.
Ferocactus latispinus is a species of barrel cactus native to Mexico. Originally described as Cactus latispinus in 1824 by English naturalist Adrian Hardy Haworth, it gained its current name in 1922 with the erection of the genus Ferocactus by American botanists Britton and Rose. The species name is derived from the Latin latus "broad", and spinus "spine". Ferocactus recurvus is a former name for the species.
Echinocereus dasyacanthus is a member of the cactus family, Cactaceae. It is one of about 2000 total species belonging to this family. The cactus is commonly known as Texas rainbow cactus because of the subtle rings or bands of contrasting colors along the stem of the plant. Not all Texas rainbow cacti have the "rainbow" coloration on their stems. Another common name is spiny hedgehog cactus.
Pachycereus pecten-aboriginum is a columnar cactus plant native to Mexico. They can grow up to 15 m (49 ft) high. The trunk of this species is 1.2 to 5.0 m tall and the fruits are large and burr-like. The specific name, pecten-aboriginum, is from the Latin, and means "native combs". It was inspired by the use of the fruits as hair combs.
Ipomoea arborescens, the tree morning glory, is a rapidly-growing, semi-succulent flowering tree in the family Convolvulaceae. This tropical plant is mostly found in Mexico, and flowers in late autumn and winter. Its common name in Nahuatl is Cazahuatl or Cazahuate.
Meconopsis horridula, the prickly blue poppy, is a flowering plant from the family Papaveraceae. It is an endangered species that grows in high altitudes. The height of the plant varies from 20 cm to 1m. It is a monocarpic, dicot plant.
Ferocactus fordii is a species of flowering plant in the family Cactaceae, native to Baja California in Mexico. It is spherical, growing to 50 cm (20 in) in diameter, with whitish-grey radial spines and solitary flowers of a deep rose pink, 4 cm (2 in) in diameter.
Coryphantha robustispina, C. robustispina subsp. robustispina is called the Pima pineapple, is a federally protected cactus of the Sonoran Desert. It is commonly found in Pima County, Arizona although it is also found throughout New Mexico and as far east as Texas.
Stenocactus multicostatus, the brain cactus, is a member of the cactus family native to the deserts of Mexico, and is popular in the gardening community. Though it has only been reported in the shrublands of Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí, Zacatecas, and Tamaulipas, it has yet to be assessed using the IUCN Categories and Criteria because its taxonomy is still unclear.
