The 1,500 to 1,800 species of cacti mostly fall into one of two groups of "core cacti": opuntias (subfamily Opuntioideae) and "cactoids" (subfamily Cactoideae). Most members of these … See more

Naming and classifying cacti has been both difficult and controversial since the first cacti were discovered for science. The difficulties began with See more

Phylogeny
A 2005 study suggested the genus Pereskia as then circumscribed (Pereskia sensu lato) was basal within the Cactaceae, but confirmed earlier suggestions it was not monophyletic, i.e., did not include all the … See more

Cactus flowers are pollinated by insects, birds and bats. None are known to be wind-pollinated and self-pollination occurs in only a very few species; for example the flowers of some species of Frailea do not open (cleistogamy). The need to attract pollinators See more

All cacti have some adaptations to promote efficient water use. Most cacti—opuntias and cactoids—specialize in surviving in hot and dry environments (i.e. are See more

Cacti inhabit diverse regions, from coastal plains to high mountain areas. With one exception, they are native to the Americas, where their range … See more

Early history
As of March 2012 , there is still controversy as to the precise dates when humans first entered those areas of the New World where … See more