The term "United States," when used in the geographical sense, refers to the contiguous United States, Alaska, Hawaii, the five insular territories of Puerto Rico, Northern Mariana Islands, U.S. Virgin Islands, Guam, American Samoa, and minor outlying possessions. The United States shares land borders with Canada and Mexico and maritime borders with Russia, Cuba, The Bahamas, and many other countries, mainly in the Caribbeanin addition to Canada and Mexico. The northern border of the United States with Canada is the world's longest bi-national land border.
The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface.
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone.
A phytochorion, in phytogeography, is a geographic area with a relatively uniform composition of plant species. Adjacent phytochoria do not usually have a sharp boundary, but rather a soft one, a transitional area in which many species from both regions overlap. The region of overlap is called a vegetation tension zone.
Antarctic flora are a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana. Presently, species of Antarctica flora reside on several now separated areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia, and New Caledonia. Joseph Dalton Hooker was the first to notice similarities in the flora and speculated that Antarctica had served as either a source or a transitional point, and that land masses now separated might formerly have been adjacent.
The ecology of California can be understood by dividing the state into a number of ecoregions, which contain distinct ecological communities of plants and animals in a contiguous region. The ecoregions of California can be grouped into four major groups: desert ecoregions, Mediterranean ecoregions, forested mountains, and coastal forests.
The Boreal Kingdom or Holarctic Kingdom (Holarctis) is a floristic kingdom identified by botanist Ronald Good, which includes the temperate to Arctic portions of North America and Eurasia. Its flora is inherited from the ancient supercontinent of Laurasia. However, parts of the floristic kingdom were glaciated during the Pleistocene and as a consequence have a very young flora. Cenozoic relicts found refuge in the southern and mountainous parts of the kingdom, especially in the Eastern Asiatic Region and southern North American Atlantic Region.
The California Floristic Province (CFP) is a floristic province with a Mediterranean-type climate located on the Pacific Coast of North America with a distinctive flora similar to other regions with a winter rainfall and summer drought climate like the Mediterranean Basin. This biodiversity hotspot is known for being the home of the Sierran giant sequoia tree and its close relative the coast redwood. In 1996, the Province was designated as a biodiversity hotspot allowing it to join ranks among 33 other areas in the world with many endemic species. To be named a biodiversity hotspot, an area has to contain species and plant life that cannot be found anywhere else in the world. The California Floristic Province is home to over 3,000 species of vascular plants, 60% of which are endemic to the province.
The Cape Floral Region is a floristic region located near the southern tip of South Africa. It is the only floristic region of the Cape Floristic Kingdom, and includes only one floristic province, known as the Cape Floristic Province.
The World Geographical Scheme for Recording Plant Distributions (WGSRPD) is a biogeographical system developed by the international Biodiversity Information Standards (TDWG) organization, formerly the International Working Group on Taxonomic Databases. The WGSRPD standards, like other standards for data fields in botanical databases, were developed to promote "the wider and more effective dissemination of information about the world's heritage of biological organisms for the benefit of the world at large". The system provides clear definitions and codes for recording plant distributions at four scales or levels, from "botanical continents" down to parts of large countries. The codes may be referred to as TDWG geographical codes. Current users of the system include the International Union for Conservation of Nature (IUCN), the Germplasm Resources Information Network (GRIN), and Plants of the World Online (POWO).
Allium cernuum, known as nodding onion or lady's leek, is a perennial plant in the genus Allium. It grows in open areas in North America.
Eurybia sibirica, commonly known as the Siberian aster or arctic aster, is an herbaceous perennial native to north western North America and northern Eurasia. It is found largely in open areas of subarctic boreal forests, though it is also found in a wide variety of habitats in the region. It is similar in appearance to Eurybia merita, but their ranges overlap only near the border between the US and Canada, where E. sibirica is generally found at higher elevations.
The North American Atlantic Region is a floristic region within the Holarctic Kingdom identified by Armen Takhtajan and Robert F. Thorne, spanning from the Atlantic and Gulf coasts to the Great Plains and comprising a major part of the United States and southeastern portions of Canada. It is bordered by the Circumboreal floristic region in the north, by the Rocky Mountain and Madrean floristic regions in the west and by the Caribbean floristic region of the Neotropical Kingdom in the south of Florida. The flora of the region comprises two endemic monotypic families, Hydrastidaceae and Leitneriaceae, and is characterized by about a hundred of endemic genera. The degree of species endemism is very high, many species are Tertiary relicts, which survived the Wisconsin glaciation and are now concentrated in the Appalachians and the Ozarks. A number of genera are shared only with the Canadian floristic province of the Circumboreal region. Moreover, as has long been noted, a large number of relict genera are shared with the relatively distant Eastern Asiatic Region and sometimes Southeast Asia. R. F. Thorne counted at least 74 genera restricted to eastern North America and Asia. The fossil record indicates that during the Tertiary period a warm temperate zone extended across much of the Northern Hemisphere, linking America to Asia.
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 Eastern Asiatic Region is the richest floristic region within the Holarctic Kingdom and situated in temperate East Asia. It has been recognized as a natural floristic area since 1872 August Grisebach's volume Die Vegetation der Erde and later delineated by such geobotanists as Ludwig Diels, Adolf Engler, Ronald Good and Armen Takhtajan.
The Rocky Mountain Floristic Region is a floristic region within the Holarctic Kingdom in western North America delineated by Armen Takhtajan. The region extends from Kodiak Island in Alaska to the San Francisco Bay Area and Sierra Nevada in California. It consists of two provinces, the Vancouverian, which comprises the coastal part of the region for its entire length, including the Pacific Coast Ranges, and the Rocky Mountain, which includes the Rocky Mountains and associated ranges. There are no endemic plant families in the region but many endemic genera and species.
The Madrean Region is a floristic region within the Holarctic Kingdom in North America, as delineated by Armen Takhtajan and Robert F. Thorne. It occupies arid or semiarid areas in the southwestern United States and northwestern Mexico and is bordered by the Rocky Mountain Floristic Region and North American Atlantic Region of the Holarctic Kingdom in the north and in the east, Caribbean Region of the Neotropical Kingdom in the south.
The Circumboreal Region in phytogeography is a floristic region within the Holarctic Kingdom in Eurasia and North America, as delineated by such geobotanists as Josias Braun-Blanquet and Armen Takhtajan.
The Paleotropical Kingdom (Paleotropis) is a floristic kingdom composed of the tropical areas of Africa, Asia and Oceania, as proposed by Ronald Good and Armen Takhtajan. Part of its flora is inherited from the ancient supercontinent of Gondwana or exchanged later. These Gondwanan lineages are related to those in the Neotropical Kingdom, composed of the tropical areas of Central and South America. Flora from the Paleotropical Kingdom influenced the tropical flora of the Australian Kingdom. The kingdom is subdivided into five floristic subkingdoms according to Takhtajan and about 13 floristic regions. In this article the floristic subkingdoms and regions are given as delineated by Takhtajan.
Allium dictuon is a species of wild onion known by the common name Blue Mountain onion. It is native to a small section of the Blue Mountains straddling the border between southeastern Washington and northeastern Oregon in the United States. It grows in Columbia, Garfield and Walla Walla Counties in Washington, plus Umatilla and Wallowa Counties in Oregon.
