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. 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.
Carduus nutans, with the common names musk thistle, nodding thistle, and nodding plumeless thistle, is a biennial plant in the daisy and sunflower family Asteraceae. It is native to regions of Europe and Asia.
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 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.
Melocactus, also known as the Turk's cap cactus, is a genus of cactus with about 30–40 species. They are native to the Caribbean, western Mexico through Central America to northern South America, with some species along the Andes down to southern Peru, and a concentration of species in northeastern Brazil.
Astrophytum myriostigma, the bishop's cap cactus, bishop's hat or bishop's miter cactus, is a species of cactus native to the highlands of northeastern and central Mexico.
Weingartia is a genus in the family Cactaceae, with species native to Bolivia and Argentina.
Echinopsis spachiana, commonly known as the golden torch, (white) torch cactus or golden column, is a species of cactus native to South America. Previously known as Trichocereus spachianus for many years, it is commonly cultivated as a pot or rockery plant worldwide. It has a columnar habit, with a lime-green cylindrical body with 1–2 cm long golden spines.
Opuntia stricta is a large sized species of cactus that is endemic to the subtropical and tropical coastal areas of the Americas, especially around the Caribbean. Common names include erect prickly pear and nopal estricto (Spanish). The first description as Cactus strictus was published in 1803 by Adrian Hardy Haworth. In 1812 he introduced the species in the genus Opuntia.
Aporocactus martianus is a species of cactus found in Oaxaca, Mexico.
Mammillaria guelzowiana is a species of plant in the family Cactaceae. The species epithet guelzowiana honors the German cactus collector Robert Gülzow of Berlín.
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.
Acanthocereus tetragonus, is a species of cactus that is native to Florida and the Lower Rio Grande Valley of Texas in the United States, Mexico, Central America, the Caribbean, and northern South America. The species is invasive in New Caledonia. Common names include night-blooming cereus, barbed-wire cactus, sword-pear, dildo cactus, triangle cactus, and Órgano-alado de pitaya (Spanish). It was originally described by Carl Linnaeus in 1753 as Cactus tetragonus but was moved to the genus Acanthocereus in 1938 by Pieter Wagenaar Hummelinck.
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.
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.
Sclerocactus sileri, the Siler fishhook cactus, is a rare and very small cactus found mostly in mineral-rich desert areas of intermediate elevations, notably in the American states of Utah, Nevada, and northern Arizona.
Mammillaria marksiana is a cactus in the genus Mammillaria of the family Cactaceae.
Mammillaria magnimamma, common name Mexican pincushion, is a species of flowering plant in the cactus family Cactaceae.
Parodia mammulosa is a species of succulent plant in the family Cactaceae.
Echinocereus stramineus is a species of cactus in which stramineus means made of straw. There are various common names such as strawberry cactus, porcupine hedgehog cactus, straw-color hedgehog, and pitaya. The straw-colored spines make this particular plant distinguished from other Echinocereus. The aged spines may turn to white color and are very fragile.
Melocactus lemairei is a species of cactus endemic to the Caribbean island of Hispaniola. It is named after French botanist and cactus expert Charles Antoine Lemaire.
