View source for Salix polaris

{{Short description|Species of willow}}
{{Speciesbox
|image = polarwillow1.jpg
|genus = Salix
|species = polaris
|authority = [[Göran Wahlenberg|Wahlenb.]]
}}

'''''Salix polaris''''', the '''polar willow''', is a species of [[willow]] with a circumpolar distribution in the high [[arctic]] [[tundra]], extending north to the limits of land, and [[Subarctic|south of the Arctic]] in the mountains of [[Norway]], the northern [[Ural Mountains]], the northern [[Altay Mountains]], [[Kamchatka]], and [[British Columbia]], [[Canada]].<ref name=scaa>Salicaceae of the Canadian Arctic Archipelago: [https://www.mun.ca/biology/delta/arcticf/sal/www/wlsapo.htm ''Salix polaris''] {{webarchive|url=https://web.archive.org/web/20120314022729/http://www.mun.ca/biology/delta/arcticf/sal/www/wlsapo.htm |date=2012-03-14 }}</ref><ref name=bc>Plants of British Columbia: [http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Salix+polaris ''Salix polaris'']</ref><ref name=dvf>Den Virtuella Floran: [http://linnaeus.nrm.se/flora/di/salica/salix/salipol.html ''Salix polaris'' (in Swedish, with maps)]</ref><ref name=grin>{{GRIN | accessdate = 21 January 2018}}</ref>

==Description==
One of the smallest willows in the world, it is a prostrate, creeping dwarf [[shrub]], only {{convert|2|-|9|cm|in|abbr=on}} high, and has underground branches or runners in the uppermost soil layers. The [[leaf|leaves]] are rounded-ovate, 5–32&nbsp;mm long and 8–18&nbsp;mm broad, dark green with entire margins. It is [[plant sexuality|dioecious]], with separate female and male plants. The [[flower]]s are grouped in short [[catkin]]s each bearing only a few flowers. The [[fruit]] is a brownish and hairy [[capsule (fruit)|capsule]]. The long runners with freely rooting stems creep in mats of [[moss]]es and [[lichen]]s, which keeps them together and protects them from the wind. It grows as well in open [[gravel]] as in closed vegetation.<ref name=scaa/><ref name=bc/><ref name=blamey>Blamey, M. & Grey-Wilson, C. (1989). ''Flora of Britain and Northern Europe''. {{ISBN|0-340-40170-2}}</ref>

[[Fossil]] remains of the species from the [[Pleistocene]] [[ice age]]s are known in Europe south to southern England, the [[Alps]], and the [[Carpathians]].<ref name=dvf/>

The species has also been reported from [[Arizona]],<ref name=dvf/><ref name=grin/> but this is not accepted by the USDA.<ref name=usda>USDA Plants Profile: [https://plants.usda.gov/java/profile?symbol=SAPO ''Salix polaris'']</ref>

==References==
{{Commons}}
{{Reflist}}

{{Taxonbar|from=Q39648}}

[[Category:Salix|polaris]]
[[Category:Flora of the Arctic]]
[[Category:Flora of Subarctic America]]
[[Category:Flora of Northern Europe]]
[[Category:Flora of the Russian Far East]]
[[Category:Flora of Siberia]]
[[Category:Flora of Western Canada]]
[[Category:Flora without expected TNC conservation status]]
[[Category:Taxa named by Göran Wahlenberg]]