The Antarctic Floristic Kingdom, also the Holantarctic Kingdom, is a floristic kingdom that includes most areas of the world south of 40°S latitude. It was first identified by botanist Ronald Good, and later by Armen Takhtajan. The Antarctic Floristic Kingdom is a classification in phytogeography, different from the Antarctic realm classification in biogeography, and from Antarctic flora genera/species classifications in botany.
The Antarctic Floristic Kingdom includes the continent of Antarctica, Patagonia (southern Chile, southern Argentina, Tierra del Fuego), most of New Zealand, the New Zealand Subantarctic Islands, and all islands of the Southern Ocean south of 40°S latitude, including Gough Island, the Kerguelen Islands, and the Falkland Islands. Tasmania is omitted since its plant species are more closely related to those found in the Australian Floristic Kingdom.
The flora of the Antarctic Kingdom dates back to the time of Gondwana, the southern supercontinent which once included most of the landmasses of the present-day Southern Hemisphere, though it has been influenced by the flora of the Holarctic Kingdom since the Tertiary period. Ronald Good noted, as had Joseph Dalton Hooker much earlier, that many plant species of Antarctica, temperate South America and New Zealand were very closely related, despite their disjunction by the vast Southern Ocean.
According to Ronald Good, about 50 genera of vascular plants are common in the Antarctic Floristic Kingdom, including Nothofagus and Dicksonia. Takhtajan also made note of hundreds of other vascular plant genera scattered and isolated on islands of the Southern Ocean, including Calandrinia feltonii of the Falkland Islands, Pringlea antiscorbutica of the Kerguelen Islands, and the megaherb genera of the New Zealand Subantarctic Islands.
According to Takhtajan, the following families are endemic or subendemic to this kingdom: Thyrsopteridaceae, Lactoridaceae, Gomortegaceae, Hectorellaceae (Hectorella), Halophytaceae, Malesherbiaceae, Francoaceae, Aextoxicaceae, Vivianiaceae, Misodendraceae, Tribelaceae, Griseliniaceae and Alseuosmiaceae.
The Antarctic Floristic Kingdom is subdivided into four floristic regions, and subdivided even further into sixteen floristic provinces. Most of the provinces lie within, or very near the Antarctic convergence zone.
The Floristic Regions in the Antarctic Floristic Kingdom are the:
The Fernandezian Region is often also included within the Neotropical Kingdom. It includes the Juan Fernández Islands and Desventuradas Islands archipelagoes off the west coast of Chile.
Within southern South America, in regions of Chile and Argentina.
The greater New Zealand islands region, including: the Zealandia islands (e.g. North Island, South Island), the New Zealand outlying islands, and the New Zealand Subantarctic Islands.
The South Subantarctic Islands