{{Short description|Species of flowering plant}} {{Speciesbox |image = Salix glauca hg.jpg |status = LC |status_system = IUCN3.1 |status_ref = <ref name=iucn>{{Cite iucn |title=''Salix glauca'' |author=Stritch, L. |name-list-style=amp |article-number= e.T79927480A126589484 |date=2018 |doi=10.2305/IUCN.UK.2018-2.RLTS.T79927480A126589484.en |access-date=11 April 2024}}</ref> |status2 = G5 |status2_system = TNC |genus = Salix |species = glauca |authority = [[Carl Linnaeus|L.]] |synonyms = ''Salix pseudolapponum'' }} [[File:Greenland scoresby-sydkapp2 hg.jpg|thumb|Dominating the Greenland tundra]]
'''''Salix glauca''''' is a species of flowering plant in the [[Salicaceae|willow family]] known by the common names '''gray willow''', '''grayleaf willow''', '''white willow''', and '''glaucous willow'''. It is native to North America, where it occurs throughout much of [[Alaska]], northern and western Canada, and the contiguous United States south through the [[Rocky Mountains]] to northern [[New Mexico]].<ref name=feis>Uchytil, Ronald J. 1992. [http://www.fs.fed.us/database/feis/plants/tree/salgla/all.html ''Salix glauca''.] In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.</ref> It can also be found in [[Greenland]], northwestern Europe, and Siberia.<ref name="PAF">{{cite web|url=http://nhm2.uio.no/paf/580213|title=580213 ''Salix glauca L.''|work=Annotated Checklist of the Panarctic Flora Vascular plants|publisher=The Panarctic Flora (PAF) Project|access-date=28 February 2012}}</ref>
== Description == This [[willow]] is usually a [[shrub]] growing up to {{convert|1.2|m|ft|abbr=on}} tall, but in appropriate habitat it becomes a tree up to {{convert|6|m|ft|abbr=on}} tall. The smooth gray bark becomes furrowed with age. The species is [[plant sexuality|dioecious]], with male and female reproductive parts occurring on separate individuals.<ref name=feis/> This species has secondary [[sexual dimorphism]], with male and female individuals different in function or morphology in aspects other than their reproductive structures. For example, female plants are more sensitive to [[drought]] conditions.<ref name=pmid21642123>{{Citation | title = Ecological correlates of secondary sexual dimorphism in Salix glauca (Salicaceae). | year = 2006 | author = Dudley, L.S. | journal = [[American Journal of Botany]] | pages = 1775–83 | volume = 93 | issue = 12 | pmid = 21642123 | doi=10.3732/ajb.93.12.1775 }}</ref> The seed stays on the plant until fall, when it is [[seed dispersal|dispersed]]. The seed is coated in downy fibers that help it disperse on the wind and on water. Unlike the seeds of many other willows, these do not [[germination|germinate]] immediately on contact with the substrate, but overwinter under the snow and sprout in the spring. This provides cold [[stratification (botany)|stratification]] to the seeds, and allows them a few weeks more to develop than in summer-dispersing willows.<ref name=feis/>
== Distribution and habitat == In the northern part of its range, this plant codominates with other species of willow on [[floodplain]]s and in shrubby riparian and [[tundra]] habitat. It may also grow scattered throughout coniferous forests and woodlands, dominated often by [[spruce]]s. In the southern part of its range, it grows in [[alpine climate|alpine]] and [[subalpine climates]]. Like many other willows, it colonizes freshly cleared habitat, such as floodplains recently scoured by water and forests recently burned.<ref name=feis/>
== Taxonomy == The taxonomy of ''S. glauca'' has been described as "confusing".<ref name="CAA Flora">{{cite web|url=http://nature.ca/aaflora/data/www/wlsagc.htm |title=Flora of the Canadian Arctic Archipelago – ''Salix glauca L. subsp. callicarpaea'' (Trautv.) Böcher |author1=S.G. Aiken |author2=M.J. Dallwitz |author3=L.L. Consaul |author4=C.L. McJannet |author5=R.L. Boles |author6=G.W. Argus |author7=J.M. Gillett |author8=P.J. Scott |author9=R. Elven |author10=M.C. LeBlanc |author11=L.J. Gillespie |author12=A.K. Brysting |author13=H. Solstad |author14=J.G. Harris |name-list-style=amp |publisher=NRC Research Press, National Research Council of Canada, Ottawa |date=2007 |access-date=2012-02-28}}</ref> With considerable geographic variation across its wide circumboreal-polar range, ''S. glauca'' may be considered "a very widespread and polymorphic species or species group", with currently no consensus whether it should be subdivided into races, subspecies or varieties. Formally and informally, there are a number of recognized subspecies (such as ''glauca'', ''stipulifera'', ''acutifolia'', ''callicarpaea'')<ref name="PAF"/> and varieties (such as ''acutifolia'', ''glauca'', ''stipulata'', ''villosa''),<ref name="ITIS22482">{{cite web|url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=22482|title=''Salix glauca'' L., Taxonomic Serial No.: 22482|work=ITIS Report|publisher=[[Integrated Taxonomic Information System]]|access-date=28 February 2012}}</ref> but there are only small morphological differences to tell them apart.<ref name="PAF"/> Furthermore, ''S. glauca'' is known to form hybrids with other willows, resulting in intermediates that are visually difficult to distinguish from one another.<ref name="CAA Flora"/> Some varieties and subspecies have very specific or limited distribution, though. The hybrid ''S. arctophila × S. glauca'' subsp. ''callicarpaea'', for instance, is not found in Canada, and is common in eastern parts of [[Greenland]], but absent from the west, whereas ''S. glauca'' subsp. ''glauca'' is not found on Greenland at all.<ref name="CAA Flora"/>
== Ecology == As with other willows, ''S. glauca'' is an important food source for a variety of animals, particularly wintering [[ungulate]]s, providing them with a rich source of calcium and phosphorus. It is considered moderately important as moose [[Browsing (herbivory)|browse]], and during the winter it constitutes much of the diet for [[snowshoe hare]]s.<ref name=feis/>
== Use == [[Native Americans in the United States|Native Americans]] used parts of willows, including this species, for medicinal purposes, in basket weaving, to make bows and arrows, and for building animal traps.<ref name=feis/>
==References== {{Reflist}}
==External links== {{Commons|Salix glauca|''Salix glauca''}}{{Wikispecies}} *[http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Salix+glauca The Nature Conservancy] *[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200005841 Flora of North America]
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[[Category:Salix|glauca]] [[Category:Plants described in 1753]] [[Category:Botanical taxa named by Carl Linnaeus]]