Opuntia including antelopes, non-human primates, elephants, birds, and humans. When Carl Linnaeus published "Species Plantarum" in 1753 – the starting point for modern botanical nomenclature – he placed all the species of cactus known to him in one genus, "Cactus". In 1754, the Scottish botanist Philip Miller divided cacti into several genera, including "Opuntia". He distinguished the genus largely on the form of its flowers and fruits. There is considerable variation of taxonomy within "Opuntia" species, resulting in names being created for variants or subtypes within a species, and use of DNA sequencing to define and isolate various species. "Opuntia" hybridizes
Opuntia ficus-indica 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. "Opuntia ficus-indica" is polyploid, hermaphrodite and autogamous. As "Opuntia" species grow in semi-arid environments, the main limiting factor in their environment is water. They have developed a number of adaptations to dry conditions, notably succulence. The perennial shrub "Opuntia ficus-indica" can grow up to 3-5m height, with thick, succulent and oblong to spatulate stems called cladodes. It has a water-repellent and sun-reflecting waxy epidermis. Cladodes that are 1–2 years old produce flowers, the