(L.) Miller, The Gardeners Dictionary: eighth edition Opuntia n. 2, 1768
What is Opuntia ficus-indica?
Opuntia ficus-indica is a prickly pear species derived from several wild ancestors. It is generally a spineless prickly pear, but some cultivars have spines.
O. ficus-indica is a large plant (tall and woody). It is actually a collection of Opuntia cultivars rather than a discrete species. The various cultivars probably have differing admixtures of genes from O. streptacantha, O. tomentosa, O. hypiacantha, O. megacantha, and O. leucotricha.
It is not native to the United States but is included here because it has naturalized in essentially frost-free regions of the country. It was developed in Mexico where the young cladodes (nopales) are consumed as a vegetable and the sweet fruits (tunas) are enjoyed. This Opuntia may have been used as human food for up to 9,000 years. Spineless opuntias were chosen over the millennia while the crop was developed.
Many forms are octoploid, but multiple ploides have been reported which likely refer to its complicated heritage.
O. ficus-indica is one of the most widespread opuntias in the world, found on all continents except Antarctica. It has become naturalized in many warms areas. O. ficus-indica grows well in mesic soils but tolerates some drought. It withstands high humidity and rain. It reproduces easily by clonal means and this facilitates its spread to the point where it is a serious weed in some areas, disrupting pastures and croplands. Britton and Rose described the plant as having a woody trunk and growing up to 3 m tall.
Some clones of O. ficus-indica can hybridise with other Opuntia species in controlled settings, including O. lindheimeri, though it is not clear if the progeny of wide crosses are fertile or if such hybridization is frequent in Nature.
One special use of O. ficus-indica is as a host for the cochineal insect (Dactylopius spp.). These scale insects grow on the surface of the plants. The female insects produce a red exudate (carminic acid) that may be a defensive chemical. The exudate is collected and used to make a red dye which is used in production of cloth, cosmetics, and food coloring, etc.
This Opuntia was popularized as a source of animal or human food in the United States around the beginning of the 20th Century. But, its successful adoption was not achieved over a wide area in part because it is cold sensitive. It is still employed for as animal food in some situations.