Opuntia in the context of "List of edible cacti"

The lotus effect refers to self-cleaning properties that are a result of ultrahydrophobicity as exhibited by the leaves of Nelumbo, the lotus flower. Dirt particles are picked up by water droplets due to the micro- and nanoscopic architecture on the surface, which minimizes the droplet's adhesion to that surface. Ultrahydrophobicity and self-cleaning properties are also found in other plants, such as Tropaeolum (nasturtium), Opuntia (prickly pear), Alchemilla, cane, and also on the wings of certain insects.

The phenomenon of ultrahydrophobicity was first studied by Dettre and Johnson in 1964 using rough hydrophobic surfaces. Their work developed a theoretical model based on experiments with glass beads coated with paraffin or PTFE telomer. The self-cleaning property of ultrahydrophobic micro-nanostructured surfaces was studied by Wilhelm Barthlott and Ehler in 1977, who described such self-cleaning and ultrahydrophobic properties for the first time as the "lotus effect"; perfluoroalkyl and perfluoropolyether ultrahydrophobic materials were developed by Brown in 1986 for handling chemical and biological fluids. Other biotechnical applications have emerged since the 1990s.

The cochineal (/ˌkɒtʃɪˈniːl, ˈkɒtʃɪniːl/ KOTCH-in-EEL, -⁠eel, US also /ˌkoʊtʃɪˈniːl, ˈkoʊtʃɪniːl/ KOH-chin-EEL, -⁠eel; Dactylopius coccus) is a scale insect in the suborder Sternorrhyncha, from which the natural dye carmine is derived. A primarily sessile parasite native to tropical and subtropical South America through North America (Mexico and the Southwest United States), this insect lives on cacti in the genus Opuntia, feeding on plant moisture and nutrients. The insects are found on the pads of prickly pear cacti, collected by brushing them off the plants, and dried.

The insect produces carminic acid that deters predation by other insects. Carminic acid, typically 17–24% of dried insects' weight, can be extracted from the body and eggs, then mixed with aluminium or calcium salts to make carmine dye, also known as cochineal. Today, carmine is primarily used as a colorant in food and in lipstick (E120 or Natural Red 4).

The peyote (Lophophora williamsii) is a small, spineless cactus which contains psychoactive alkaloids, particularly mescaline. Peyote is a Spanish word derived from the Nahuatl peyōtl, meaning "caterpillar cocoon", from a root peyōni, "to glisten".

It is native to southern North America, primarily found in desert scrub and limestone-rich areas of northern Mexico and south Texas, particularly in the Chihuahuan Desert at elevations of 100–1500 meters. It flowers from March to May, and sometimes as late as September. Its flowers are pink or white, with thigmotactic anthers (like Opuntia). It is a small, spineless cactus that grows in clusters, produces edible fruits, and contains psychoactive alkaloids—primarily mescaline—at concentrations of about 0.4% when fresh and up to 6% when dried.

Opuntia engelmannii is a prickly pear common across the south-central and Southwestern United States and northern Mexico. It goes by a variety of common names, including desert prickly pear, discus prickly pear, Engelmann's prickly pear in the US, and nopal, abrojo, joconostle, and vela de coyote in Mexico.

The nomenclatural history of this species is somewhat complicated due to the varieties, as well as its habit of hybridizing with Opuntia phaeacantha. It differs from O. phaeacantha by being green year round instead of turning reddish purple during winter or dry seasons, as well as having yellow flowers with red centers.

Opuntia ficus-indica, the Indian fig opuntia, fig opuntia, or prickly pear, is a species of cactus that has long been a domesticated crop plant grown in agricultural economies throughout arid and semiarid parts of the world. O. ficus-indica is the most widespread and most commercially important cactus. It is grown primarily as a fruit crop, and also for the vegetable nopales and other uses. Cacti are good crops for dry areas because they efficiently convert water into biomass. O. ficus-indica is the most widespread of the long-domesticated cactuses. Opuntia species hybridize easily, but the wild origin of O. ficus-indica is likely to have been in central Mexico, where its closest genetic relatives are found.