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
Plant functional type Plant functional type Plant functional types (PFTs) is a system used by climatologists to classify plants according to their physical, phylogenetic and phenological characteristics as part of an overall effort to develop a vegetation model for use in land use studies and climate models. PFTs provide a finer level of modeling than biomes, which represent gross areas such as desert, savannah, deciduous forest. In creating a PFT model, areas as small as 1 km are modeled by defining the predominant plant type for that area, interpreted from satellite data or other means. For each plant functional type, a number of