Included here is the northern treeless regions of Europe, Siberia and North America, and all of the islands north of the Arctic Circle including Greenland and Iceland.  In the Bering Sea its southern boundary includes the Aleutian Islands and Kodiak Island.

Arctic Tundra

The most characteristic plant formation of the arctic is tundra. In the southern zones it is typically composed of shrubby species, which are either evergreen with small thick leaves as in Arctostaphylos alpinus (alpine bearberry), Ledum palustre (Labrador tea), Loiseleuria procumbens (trailing azalea) and Phyllodoce caerulea (blue heath), or deciduous such as Betula nana (dwarf birch), Salix herbacea (dwarf willow), S. polaris and S. reticulata (net leaved willow). In these more heathy areas, endemic species such as Antennaria glabrate and A. hansii (Astereaceae), Oxytropis artobia and O. terrae-novae (Fabeaceae), and the near endemic moonwort Botrychium borealis (Ophioglossaceae) may be found, although some of these are confined to the more calcareous areas.  In such areas, arctic herbaceous species like Dryas octopetala (mountain avens) may dominant relatively rich association of species such as Arnica alpina, Campanula uniflora, Draba nivalis, Oxytropis lapponica, and Potentilla nivea, while in more acidic areas, graminoids such as Alopecurus, Arctophila, Arctagrostis, Carex and the endemic genus Dupontia may predominate. In Alaska, the drier areas may include the endemic grass Arctagrostis latifolia (Poaceae) as one of the main species, but with increasing wetness the endemic Dupontia fisheri is becomes more prevalent. This latter can also tolerate complete immersion, but where there is more permanent standing water the endemic Arctophila fulva (Poaceae) may becomes the main grass species, together with species such as Hippurus vulgaris and Potentilla palustris. Other endemic species associated with grass tundra include Cardamine digitata (Brassicaceae) and Papaver keelei (Papavaceae).

References

Bliss, L. C. 1989. Arctic tundra and polar deserts. In: North American Terrestrial Vegetation. Eds. M. G. Barbour & W. D. Billings.  Cambridge University Press.

Bocher, T. W. 1972. Evolutionary problems in the Arctic flora. In: Taxonomy, Phytogeography and Evolution. Ed. D. H. Valentine. Academic Press.

Hooker, J. D. 1862. Outlines of the distribution of Arctic plants. Transactions of the Linnaean Society, London, 23:251-348.

Polunin, N. 1951.  The real Arctic: suggestions for its delimitation, subdivision and characterisation. Journal of Biogeography, 39: 300-315.

Polunin, N. 1959. Circumpolar Arctic Flora. Oxford at the Clarenden Press.

Polunin, N. 1971. Vegetation types of polar lands. In: World Vegetation Types.  Ed. S. R. Eyre. Macmillan.

Polunin, O. & Walters, M. 1985. A guide to the vegetation of Britain and Europe. Oxford University Press.

Ricketts, T. H. et al. 1999. Terrestrial Ecosystems of North America - a conservation assessment. World Wildlife Fund, USA and Canada. Island Press, Washington.

Savile, D. B. O. 1959. The botany of Somerset Island, district of Franklin. Canadian Journal of Botany, 37: 959-1002.

Savile, D. B. O. 1964. General ecology and vascular plants of the Hazen Camp area. Arctic, 17: 237-256.

Talbot, S. S. et al. 1999. Atlas of the rare endemic vascular plants of the Arctic. Conservation of Arctic Flora and Fauna (CAFF) Technical Report No. 3.