{{Short description|Species of tree}} {{Speciesbox |image = Populus heterophylla - NRCS 1.jpg |image_caption = |status = LC |status_system = IUCN3.1 |status_ref = <ref name = "iucn status 19 November 2021">{{cite iucn |author = Smith, K. |date = 2016 |title = ''Populus heterophylla'' |volume = 2016 |article-number = e.T61959850A61959867 |doi = 10.2305/IUCN.UK.2016-1.RLTS.T61959850A61959867.en |access-date = 19 November 2021}}</ref> |parent = Populus sect. Leucoides |taxon = Populus heterophylla |authority = L. |range_map = Populus heterophylla range map 1.png }}
'''''Populus heterophylla''''', also known as '''downy poplar''',<ref name=":0">{{Cite web |url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242417040 |title=Populus heterophylla in Flora of North America @ efloras.org |website=www.efloras.org |access-date=2020-04-23}}</ref> '''swamp poplar'''<ref name=":0" /> and '''swamp cottonwood''',<ref name=":2">{{Cite web|url=http://www.illinoiswildflowers.info/trees/plants/sw_cottonwd.html|title=Swamp Cottonwood (Populus heterophylla)|website=www.illinoiswildflowers.info|access-date=2020-04-23}}</ref> is a large deciduous poplar belonging to the ''Populus'' genus of the family Salicaceae. This species can grow on sites that have too much water for other native poplars.<ref name=":1">"Populus heterophyfla L". ''srs.fs.usda.gov''. Retrieved 2020-04-23.[https://srs.fs.usda.gov/pubs/misc/ag_654/volume_2/populus/heterophylla.htm]</ref> On the IUCN Red List this species is listed as "least concern".<ref>{{Cite web|url=https://www.iucnredlist.org/en|title=IUCN Red List of Threatened Species: Populus heterophylla|last=Smith (IUCN)|first=Kevin|date=2015-04-01|website=IUCN Red List of Threatened Species|access-date=2020-04-23}}</ref>
== Description == Swamp poplar can reach a height {{cvt|50|to|100|ft|m}} at maturity.<ref name=":2" /> The trunk and branches are a light to medium grey, with the trunk being coarsely furrowed.<ref name=":2" /> The leaves are alternate deciduous that are {{convert|4|to|6|in|cm}} long and {{convert|3|to|4|in|cm}} across.<ref name=":2" /> Mature leaves are medium to dark green on their upper surface and pale green on the lower surface.<ref name=":2" /> Petioles are {{convert|2|to|3|in|cm}} long and tend to be between pale green and pale yellow.<ref name=":2" /> This species is pollinated by wind.<ref name=":1" /> This species flowers in April and fruits May-June.<ref name=":0" />
== Habitat ==
=== Location === This species is indigenous to warm, temperate regions in North America, although nowhere is it considered abundant. It is found in wet bottomland forests.<ref name=":1" /> Swamp cottonwood can be found along the east coast of the United States from Connecticut to Georgia, as well as northwestern Florida and west to Louisiana.<ref name=":1" /> It also grows in the Mississippi valley, Ohio and southern Michigan.<ref name=":1" />
=== Soils and topography === ''Populus heterophylla'' is typically found on heavy clays, but can be found on the edges of swamps (not within).<ref name=":1" /> Ideal growth will happen in areas where the water table is near the surface for all but two to three months a year.<ref name=":1" />
== Climate == Humid climate is common throughout the range of the swamp poplar.<ref name=":1" /> Rainfall varies for this species based on how far north it is found. When found in Indiana, the average annual rainfall is about 35 in (890 cm); as opposed to when found in Louisiana average annual rainfall is 59 in (1500 mm).<ref name=":1" /> Yearly average temperatures range in the North and South from 50°F to 70°F respectively.<ref name=":1" />
== Special uses == There are no special uses or commercial value for this species due to the similarity to ''Populus deltoides'', which grows faster and easier.{{citation needed|date=July 2024}}
== References == <references responsive="1"></references>
==External links== * [http://www.na.fs.fed.us/spfo/pubs/silvics_manual/volume_2/populus/heterophylla.htm USDA Forest Service: Silvics of Trees of North America. ''Populus heterophylla'' L. Swamp Cottonwood] * [https://plants.usda.gov/java/nameSearch?keywordquery=swamp+cottonwood&mode=comname USDA Natural Resources Conservation Service: Plant Profiles. ''Populus heterophylla'' L. swamp cottonwood]
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heterophylla Category:Trees of Northern America Category:Plants described in 1753 Category:Botanical taxa named by Carl Linnaeus