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, as the most widespread of the long-domesticated cactuses, is as economically important as maize and blue agave in Mexico. 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. Names Most culinary references to the "prickly pear" refer to this species. The Spanish name tuna is also used for the fruit of this cactus and for Opuntia in general; according to Alexander von Humboldt, it was a word of Taino origin taken into the Spanish language around 1500. Common English names for the plant and its fruit are Indian fig opuntia, Barbary fig, cactus pear, prickly pear, and spineless cactus, among many others. In Mexican Spanish, the plant is called nopal, a name that may be used in American English as culinary terms. Peninsular Spanish mostly uses higo chumbo for the fruit and chumbera for the plant. Description O. ficus-indica is polyploid, hermaphroditic, and autogamous. As Opuntia species grow in semiarid environments, the main limiting factor in their environment is water. They have developed several adaptations to dry conditions, notably succulence. A perennial shrub, O. ficus-indica can grow up to 5 m in height, with thick, succulent, and oblong to spatulate stems called cladodes. It has a water-repellent and sun-reflecting waxy epidermis. Cladodes 1–2 years old produce flowers, with the fruit's colours ranging from pale green to deep red. The plants flower in three distinct colours: white, yellow, and red. The flowers first appear in early May through the early summer in the Northern Hemisphere, and the fruits ripen from August through October. The fruits are typically eaten, minus the thick outer skin, after chilling in a refrigerator for a few hours. They have a taste similar to sweet watermelon. The bright red/purple or white/yellowish flesh contains many tiny hard seeds that are usually swallowed but should be avoided by those who have problems