Ficus

Most culinary references to the "prickly pear" are referring to this species. The 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.
Opuntia ficus-indica, the 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. Likely having originated in Mexico, O. ficus-indica is the most widespread and most commercially important cactus.
Fig opuntia 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 convert water into biomass efficiently. O. ficus-indica, as the most widespread of the long-domesticated cactuses, is as economically important as maize and blue agave in Mexico. Because Opuntia species hybridize easily, the wild origin of O. ficus-indica is likely to have been in Mexico due to the fact that its close genetic relatives are found in central Mexico.
O. ficus-indica are consumed widely as food. The fruits are widely commercialized in many parts of the world, eaten raw, and have one of the highest concentrations of vitamin C of any fruit.