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.
Barrel cacti are various members of the two genera Echinocactus and Ferocactus, endemic to the deserts of Southwestern North America southward to north central Mexico. Some of the largest specimens are found in the Sonoran Desert.
Acanthocalycium is a genus of cactus consisting of several species from Argentina, Bolivia, Brazil, Paraguay and Uruguay. The taxon name comes from Greek akantha and kalyx, which refers to the spines on the floral tubes.
Cylindropuntia bigelovii, the teddy-bear cholla, is a cholla cactus species native to Northwestern Mexico, and to the United States in California, Arizona, and Nevada.
Echinocereus is a genus of ribbed, usually small to medium-sized, cylindrical shaped cacti, comprising about 70 species native to the southern United States and Mexico in very sunny, rocky places. Usually the flowers are large and the fruit edible.
Bergerocactus emoryi is a species of cactus, known commonly as the golden-spined cereus, golden snake cactus, velvet cactus or golden club cactus. It is a relatively small cactus, but it can form dense thickets or colonies, with the dense yellow spines giving off a velvety appearance when backlit by the sun. From April to May, yellow, green-tinged flowers emerge, which transform into reddish, globular fruit. This species is native to the California Floristic Province, and is found in northwestern Baja California and a small part of California, in San Diego County and on the southern Channel Islands. Where the Mediterranean climate of the California Floristic Province collides with the subtropical Sonoran Desert near El Rosario, hybrids with two other species of cacti are found. It is the sole member of the monotypic genus Bergerocactus, named after German botanist Alwin Berger.
Morangaya is a monotypic genus of ribbed, usually small to medium-sized, cylindrical shaped cacti, that is native to north western Mexico. The only species is Morangaya pensilis. It is found in the mountains and rocky hills.
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.
Echinocereus reichenbachii is a perennial plant and shrub in the cactus family. The species is native to the Chihuahuan Desert and parts of northern Mexico and the southern United States, where they grow at elevations up to 1,500 meters (4,900 ft). This cactus earned the Royal Horticultural Society's Award of Garden Merit.
Echinocereus triglochidiatus is a species of hedgehog cactus known by several common names, including kingcup cactus, claret cup cactus, red-flowered hedgehog cactus and Mojave mound cactus. This cactus is native to the southwestern United States and northern Mexico, where it is a resident of varied habitats from low desert to rocky slopes, scrub, and mountain woodland. E. triglochidiatus is the official state cactus of Colorado.
Pelecyphora sneedii is a rare species of cactus known by the common names Sneed's pincushion cactus and carpet foxtail cactus. It is endemic to the Chihuahuan Desert of the southwestern United States and northwestern Mexico. It is a small, variable cactus with a lengthy taxonomic history, and is often subdivided into a number of subspecies or varieties. It is usually found on steep, rocky habitats, primarily of limestone geology, in desert scrub or coniferous forest. A species of conservation concern, P. sneedii faces threats from poaching, urban encroachment, and wildfires.
Echinocereus chisoensis is a rare North American species of cactus known by the common name Chisos Mountain hedgehog cactus, native to the Chihuahuan Desert of northern Mexico and the south-central United States.
Echinocereus viridiflorus is a species of cactus known by the common names nylon hedgehog cactus, green pitaya, and small-flowered hedgehog cactus. It is native to the central and south-central United States and northern Mexico, where it can be found in varied habitat types, including desert scrub, woodlands, dry grasslands, and short-grass prairie.
Cereus ( "serious") is a genus of cacti including around 33 species of large columnar cacti from South America. The name is derived from Greek (κηρός) and Latin words meaning "wax", "torch" or "candle". Cereus was one of the first cactus genera to be described; the circumscription varies depending on the authority. The term "cereus" is also sometimes used for a ceroid cactus, any cactus with a very elongated body, including columnar growth cacti and epiphytic cacti.
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.
Thelocactus setispinus, commonly known as miniature barrel cactus or hedgehog cactus, is a species of cactus in the family Cactaceae.
Echinocereus stramineus is a species of cactus, with stramineus meaning made of straw. There are various common names such as strawberry cactus, porcupine hedgehog cactus, straw-color hedgehog, and pitaya. The straw-colored spines distinguishes this particular plant from other Echinocereus. The aged spines may turn white in color and are very fragile.
Echinocereus coccineus is a species of hedgehog cactus. Its native to Northern and Central America. It grows on full sun, in sandy or rocky well-drained soil. It can survive in hardiness zones 8–11.
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.
Echinocereus websterianus, commonly known as the San Pedro Nolasco hedgehog cactus or Webster's hedgehog cactus, is a species of cactus. It is named after American philanthropist Gertrude Webster, who cofounded the Desert Botanical Garden in Phoenix, Arizona.
