Difference between revisions of "Populus" - New World Encyclopedia

From New World Encyclopedia
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==Classification==
 
==Classification==
 
[[Image:Four Poplars.jpg|thumb|right|A group of poplars in a field]]
 
[[Image:Four Poplars.jpg|thumb|right|A group of poplars in a field]]
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The genus ''Populus'' has traditionally been divided into six sections on the basis of leaf and flower characters;<ref name=rushforth/><ref name=eckenwalder>Eckenwalder, J. E. (1977). North American cottonwoods (Populus, Salicaceae) of sections Abaso and Aigeiros. ''J. Arnold Arbor''. 58: 193-208.</ref> this classification is followed below. Recent genetic studies have largely supported this, though showing that the relationships are somewhat more complex, with some reticulate evolution due to past [[Hybrid (biology)|hybrid]]isation and introgression events between the groups; some species (noted below) had differing relationships indicated by their nuclear DNA (paternally inherited) and chloroplast DNA sequences (maternally inherited), a clear indication of likely hybrid origin.<ref name=hamzeh>Hamzeh, M., & Dayanandan, S. (2004). Phylogeny of Populus (Salicaceae) based on nucleotide sequences of chloroplast TRNT-TRNF region and nuclear rDNA. ''Amer. J. Bot''. 91: 1398-1408. Available [http://www.amjbot.org/cgi/content/full/91/9/1398 online]</ref> Hybridisation continues to be common in the genus, with several hybrids between species in different sections known.<ref name=rdm/>
+
The genus ''Populus'' has traditionally been divided into six sections on the basis of [[leaf]] and [[flower]] characters (Rushforth 1999; Eckenwalder 1977). This classification is followed below. Recent genetic studies have largely supported this, though showing that the relationships are somewhat more complex, with some reticulate evolution due to past [[Hybrid (biology)|hybrid]]ization and introgression events between the groups. Some species (noted below) had differing relationships indicated by their nuclear [[DNA]] (paternally inherited) and [[chloroplast]] DNA sequences (maternally inherited), a clear indication of likely hybrid origin (Hamzeh and Dayanandan 2004). Hybridization continues to be common in the genus, with several hybrids between species in different sections known (Meikle 1984).  
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*'''''Populus'' section ''Populus'' - [[aspen]]s and White Poplar.''' Circumpolar subarctic and cool temperate, and mountains farther south (White Poplar warm temperate)
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*'''''Populus'' section ''Populus'' - [[aspen]]s and white poplar.''' Circumpolar subarctic and cool temperate, and mountains farther south (white poplar warm temperate)
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**''[[Populus tremula]]'' - Common Aspen, Trembling Aspen or Eurasian Aspen. Europe, northern Asia. This is the [[type species]] of the genus.  
+
**''[[Populus tremula]]'' - Common aspen, trembling aspen or Eurasian Aspen. Europe, northern Asia. This is the [[type species]] of the genus.  
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**''[[Populus adenopoda]]'' - Chinese Aspen. Eastern Asia.
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**''[[Populus adenopoda]]'' - Chinese aspen. Eastern Asia.
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**''[[Populus alba]]'' - White Poplar. Southern Europe to central Asia.
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**''[[Populus alba]]'' - White poplar. Southern Europe to central Asia.
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***''[[Populus alba|Populus × canescens]]'' (''P. alba × P. tremula'') - Grey Poplar
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***''[[Populus alba|Populus × canescens]]'' (''P. alba × P. tremula'') - Gray poplar
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**''[[Populus grandidentata]]'' - Bigtooth Aspen. Eastern North America.
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**''[[Populus grandidentata]]'' - Bigtooth aspen. Eastern North America.
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**''[[Populus sieboldii]]'' - Japanese Aspen. Eastern Asia.
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**''[[Populus sieboldii]]'' - Japanese aspen. Eastern Asia.
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**''[[Populus tremuloides]]'' - Quaking Aspen or Trembling Aspen. North America.
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**''[[Populus tremuloides]]'' - Quaking aspen or trembling aspen. North America.
  
 
*'''''Populus'' section ''Aegiros''<ref>Note: the spelling is disputed; some sources use ''Aegiros'', others use ''Aigeiros''</ref> - black poplars or [[cottonwood]]s.''' North America, Europe, western Asia; temperate
 
*'''''Populus'' section ''Aegiros''<ref>Note: the spelling is disputed; some sources use ''Aegiros'', others use ''Aigeiros''</ref> - black poplars or [[cottonwood]]s.''' North America, Europe, western Asia; temperate
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**''[[Populus deltoides]]'' - Eastern Cottonwood. Eastern North America.
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**''[[Populus deltoides]]'' - Eastern cottonwood. Eastern North America.
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**''[[Populus fremontii]]'' - Fremont Cottonwood. Western North America.
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**''[[Populus fremontii]]'' - Fremont cottonwood. Western North America.
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**''[[Populus nigra]]'' - Black Poplar. Europe. Placed here by nuclear DNA; cpDNA places in sect. ''Populus''.
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**''[[Populus nigra]]'' - Black poplar. Europe. Placed here by nuclear DNA; cpDNA places in sect. ''Populus''.
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***''[[Populus nigra|Populus × canadensis]]'' (''P. nigra × P. deltoides'') - Hybrid Black Poplar
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***''[[Populus nigra|Populus × canadensis]]'' (''P. nigra × P. deltoides'') - Hybrid black poplar
  
 
[[Image:Populus lasiocarpa leaves 01 by Line1.JPG|thumb|right|Leaves of ''Populus lasiocarpa'']]
 
[[Image:Populus lasiocarpa leaves 01 by Line1.JPG|thumb|right|Leaves of ''Populus lasiocarpa'']]
 
*'''''Populus'' section ''Tacamahaca'' - [[balsam poplar]]s.''' North America, Asia; cool temperate
 
*'''''Populus'' section ''Tacamahaca'' - [[balsam poplar]]s.''' North America, Asia; cool temperate
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**''[[Populus angustifolia]]'' - Willow-leaved Poplar or Narrowleaf Cottonwood. Central North America.
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**''[[Populus angustifolia]]'' - Willow-leaved poplar or narrowleaf cottonwood. Central North America.
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**''[[Populus balsamifera]]'' - Ontario Balsam Poplar. Northern North America.
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**''[[Populus balsamifera]]'' - Ontario balsam poplar. Northern North America.
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**''[[Populus laurifolia]]'' - Laurel-leaf Poplar. Central Asia.
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**''[[Populus laurifolia]]'' - Laurel-leaf poplar. Central Asia.
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**''[[Populus maximowiczii]]'' - Maximowicz' Poplar. Northeast Asia.
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**''[[Populus maximowiczii]]'' - Maximowicz' poplar. Northeast Asia.
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**''[[Populus simonii]]'' - Simon's Poplar. Northeast Asia.
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**''[[Populus simonii]]'' - Simon's poplar. Northeast Asia.
 
**''[[Populus szechuanica]]'' Northeast Asia. Placed here by nuclear DNA; cpDNA places in sect. ''Aegiros''.
 
**''[[Populus szechuanica]]'' Northeast Asia. Placed here by nuclear DNA; cpDNA places in sect. ''Aegiros''.
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**''[[Populus trichocarpa]]'' - Western Balsam Poplar or Black Cottonwood. Western North America.
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**''[[Populus trichocarpa]]'' - Western balsam poplar or black cottonwood. Western North America.
 
**''[[Populus tristis]]'' - Northeast Asia. Placed here by nuclear DNA; cpDNA places in sect. ''Aegiros''.
 
**''[[Populus tristis]]'' - Northeast Asia. Placed here by nuclear DNA; cpDNA places in sect. ''Aegiros''.
  
 
*'''''Populus'' section ''Leucoides'' - [[necklace poplar]]s or bigleaf poplars.''' Eastern North America, eastern Asia; warm temperate
 
*'''''Populus'' section ''Leucoides'' - [[necklace poplar]]s or bigleaf poplars.''' Eastern North America, eastern Asia; warm temperate
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**''[[Populus heterophylla]]'' - Swamp Cottonwood. Southeastern North America.
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**''[[Populus heterophylla]]'' - Swamp cottonwood. Southeastern North America.
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**''[[Populus lasiocarpa]]'' - Chinese Necklace Poplar. Eastern Asia.
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**''[[Populus lasiocarpa]]'' - Chinese necklace poplar. Eastern Asia.
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**''[[Populus wilsonii]]'' - Wilson's Poplar. Eastern Asia.
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**''[[Populus wilsonii]]'' - Wilson's poplar. Eastern Asia.
  
 
*'''''Populus'' section ''Turanga'' - subtropical poplars.''' Southwest Asia, east Africa; subtropical to tropical
 
*'''''Populus'' section ''Turanga'' - subtropical poplars.''' Southwest Asia, east Africa; subtropical to tropical
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**''[[Populus euphratica]]'' - Euphrates Poplar. Southwest Asia.
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**''[[Populus euphratica]]'' - Euphrates poplar. Southwest Asia.
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**''[[Populus ilicifolia]]'' - Tana River Poplar. East Africa.
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**''[[Populus ilicifolia]]'' - Tana river poplar. East Africa.
  
 
*'''''Populus'' section ''Abaso'' - Mexican poplars.''' Mexico; subtropical to tropical
 
*'''''Populus'' section ''Abaso'' - Mexican poplars.''' Mexico; subtropical to tropical
 
**''[[Populus guzmanantlensis]]'' Mexico.
 
**''[[Populus guzmanantlensis]]'' Mexico.
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**''[[Populus mexicana]]'' - Mexico Poplar. Mexico.
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**''[[Populus mexicana]]'' - Mexico poplar. Mexico.
  
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In the September 2006 issue of ''[[Science (journal)|Science]]'', it was announced that ''Populus trichocarpa'' was the first tree to have its full [[DNA]] code sequenced.<ref>Joint Genome Institute: [http://genome.jgi-psf.org/Poptr1_1/Poptr1_1.home.html ''Populus trichocarpa'']</ref>
+
In the September 2006 issue of ''[[Science (journal)|Science]]'', it was announced that ''Populus trichocarpa'' was the first tree to have its full [[DNA]] code sequenced (JGI 2006).
  
 
==Cultivation and uses==
 
==Cultivation and uses==
Line 112: Line 112:
  
 
== References ==
 
== References ==
 +
 +
<ref name=hamzeh>Hamzeh, M., & Dayanandan, S. (2004). Phylogeny of Populus (Salicaceae) based on nucleotide sequences of chloroplast TRNT-TRNF region and nuclear rDNA. ''Amer. J. Bot''. 91: 1398-1408. Available [http://www.amjbot.org/cgi/content/full/91/9/1398 online]</ref>
 +
 +
 +
<ref>Joint Genome Institute: [http://genome.jgi-psf.org/Poptr1_1/Poptr1_1.home.html ''Populus trichocarpa'']</ref>  2006
 +
 +
<ref name=Keeler>{{cite book | last =Keeler | first =H. L. | title =Our Native Trees and How to Identify Them | publisher =Charles Scriber's Sons | date =1900 | location =New York | pages =410-412 }}</ref>
 +
 
<ref name=rdm>Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook No. 4. ISBN 0-901158-07-0.</ref><ref name=rushforth>Rushforth, K. (1999). ''Trees of Britain and Europe''. Collins ISBN 0-00-220013-9.</ref>
 
<ref name=rdm>Meikle, R. D. (1984). ''Willows and Poplars of Great Britain and Ireland''. BSBI Handbook No. 4. ISBN 0-901158-07-0.</ref><ref name=rushforth>Rushforth, K. (1999). ''Trees of Britain and Europe''. Collins ISBN 0-00-220013-9.</ref>
  
−
<ref name=Keeler>{{cite book | last =Keeler | first =H. L. | title =Our Native Trees and How to Identify Them | publisher =Charles Scriber's Sons | date =1900 | location =New York | pages =410-412 }}</ref>
+
;<ref name=rushforth/><ref name=eckenwalder>Eckenwalder, J. E. (1977). North American cottonwoods (Populus, Salicaceae) of sections Abaso and Aigeiros. ''J. Arnold Arbor''. 58: 193-208.</ref>
  
 
[[Category:Life sciences]]
 
[[Category:Life sciences]]

Revision as of 14:24, 9 May 2008

"Poplar" redirects here.
Populus
Foliage of Populus tremula
Foliage of Populus tremula
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Malpighiales
Family: Salicaceae
Genus: Populus
L.
Sections

See text

Populus is a genus of deciduous trees in the flowering plants family Salicaceae, characterized by flowers in the form of long, drooping catkins and spirally arranged leaves with a long petiole that in many species are laterally flattened so that breezes easily cause the leaves to wobble back and forth. This can give the whole tree a "twinkling" appearance in a breeze. Common names applied to various species include aspen, cottonwood, and poplar, with the latter name sometimes applied to all members of the genus.

The Populus genus is native to most of the Northern Hemisphere.

uses


Description

Populus nigra in autumn

The Populus genus includes between 25 and 35 species, depending on the taxonomic scheme. Members are medium-sized to large or very large deciduous trees growing to 15 to 50 meters tall, with trunks up to 2.5 meters in diameter. The bark on young trees is smooth, white to greenish or dark grey, often with conspicuous lenticels; on old trees it remains smooth in some species, but becomes rough and deeply fissured in others. The shoots are stout, with (unlike in the related willows) the terminal bud present.

The leaves are spirally arranged, and vary in shape from triangular to circular or (rarely) lobed, and with a long petiole. In species in the sections Populus and Aegiros, the petioles are laterally flattened, so that breezes easily cause the leaves to wobble back and forth, giving the whole tree a "twinkling" appearance in a breeze. Leaf size is very variable even on a single tree, typically with small leaves on side shoots, and very large leaves on strong-growing lead shoots. The leaves often turn bright gold to yellow before they fall during autumn (Meikle 1984; Rushforth 1999).

Male catkins of Populus × canadensis

The flowers are mostly dioecious (rarely monoecious) and appear in early spring before the leaves. They are borne in long, drooping, sessile or pedunculate catkins produced from buds formed in the axils of the leaves of the previous year. The flowers are each seated in a cup-shaped disk that is borne on the base of a scale, which is itself attached to the rachis of the catkin. The scales are obovate, lobed and fringed, membranous, hairy or smooth, usually caducous. The male flowers are without calyx or corolla, and comprise a group of 4–60 stamens inserted on a disk. The filaments are short and pale yellow, while the anthers is oblong, purple or red, introrse, and two-celled, wiht cells opening longitudinally. The female flower also has no calyx or corolla, and comprises a single-celled ovary seated in a cup-shaped disk. The style is short, with 2–4 stigmas, variously lobed, and numerous ovules (Meikle 1984; Keeler 1900).

The plants are wind-pollinated, with the female catkins lengthening considerably between pollination and maturity. The fruit is a two to four-valved capsule, green to reddish-brown, which matures in mid summer. It contains numerous minute light brown seeds surrounded by tufts of long, soft, white hairs that aid wind dispersal (Meikle 1984; Keeler 1900).

Poplars of the cottonwood section are often wetlands or riparian trees. The aspens are among the most important boreal broadleaf trees (Meikle 1984).

Classification

A group of poplars in a field

The genus Populus has traditionally been divided into six sections on the basis of leaf and flower characters (Rushforth 1999; Eckenwalder 1977). This classification is followed below. Recent genetic studies have largely supported this, though showing that the relationships are somewhat more complex, with some reticulate evolution due to past hybridization and introgression events between the groups. Some species (noted below) had differing relationships indicated by their nuclear DNA (paternally inherited) and chloroplast DNA sequences (maternally inherited), a clear indication of likely hybrid origin (Hamzeh and Dayanandan 2004). Hybridization continues to be common in the genus, with several hybrids between species in different sections known (Meikle 1984).

  • Populus section Populus - aspens and white poplar. Circumpolar subarctic and cool temperate, and mountains farther south (white poplar warm temperate)
    • Populus tremula - Common aspen, trembling aspen or Eurasian Aspen. Europe, northern Asia. This is the type species of the genus.
    • Populus adenopoda - Chinese aspen. Eastern Asia.
    • Populus alba - White poplar. Southern Europe to central Asia.
      • Populus × canescens (P. alba × P. tremula) - Gray poplar
    • Populus grandidentata - Bigtooth aspen. Eastern North America.
    • Populus sieboldii - Japanese aspen. Eastern Asia.
    • Populus tremuloides - Quaking aspen or trembling aspen. North America.
  • Populus section Aegiros[1] - black poplars or cottonwoods. North America, Europe, western Asia; temperate
    • Populus deltoides - Eastern cottonwood. Eastern North America.
    • Populus fremontii - Fremont cottonwood. Western North America.
    • Populus nigra - Black poplar. Europe. Placed here by nuclear DNA; cpDNA places in sect. Populus.
      • Populus × canadensis (P. nigra × P. deltoides) - Hybrid black poplar
Leaves of Populus lasiocarpa
  • Populus section Tacamahaca - balsam poplars. North America, Asia; cool temperate
    • Populus angustifolia - Willow-leaved poplar or narrowleaf cottonwood. Central North America.
    • Populus balsamifera - Ontario balsam poplar. Northern North America.
    • Populus laurifolia - Laurel-leaf poplar. Central Asia.
    • Populus maximowiczii - Maximowicz' poplar. Northeast Asia.
    • Populus simonii - Simon's poplar. Northeast Asia.
    • Populus szechuanica Northeast Asia. Placed here by nuclear DNA; cpDNA places in sect. Aegiros.
    • Populus trichocarpa - Western balsam poplar or black cottonwood. Western North America.
    • Populus tristis - Northeast Asia. Placed here by nuclear DNA; cpDNA places in sect. Aegiros.
  • Populus section Leucoides - necklace poplars or bigleaf poplars. Eastern North America, eastern Asia; warm temperate
    • Populus heterophylla - Swamp cottonwood. Southeastern North America.
    • Populus lasiocarpa - Chinese necklace poplar. Eastern Asia.
    • Populus wilsonii - Wilson's poplar. Eastern Asia.
  • Populus section Turanga - subtropical poplars. Southwest Asia, east Africa; subtropical to tropical
    • Populus euphratica - Euphrates poplar. Southwest Asia.
    • Populus ilicifolia - Tana river poplar. East Africa.
  • Populus section Abaso - Mexican poplars. Mexico; subtropical to tropical
    • Populus guzmanantlensis Mexico.
    • Populus mexicana - Mexico poplar. Mexico.

In the September 2006 issue of Science, it was announced that Populus trichocarpa was the first tree to have its full DNA code sequenced (JGI 2006).

Cultivation and uses

A fastigiate Black Poplar cultivar of the Plantierensis Group, in Hungary.

Many poplars are grown as ornamental trees, with numerous cultivars selected. They have the advantage of growing very big very fast. Trees with fastigiate (erect, columnar) branching are particularly popular, and very widely grown across Europe and southwest Asia in particular. However, like willows, poplars have very vigorous and invasive root systems stretching up to 40 m from the trees; planting close to houses or ceramic water pipes may result in damaged foundations and cracked walls and pipes due to their search for moisture.

Fast-growing hybrid poplars are grown on plantations in many areas for pulpwood and used for the manufacture of paper.[2] The wood is generally white, often with a slightly yellowish cast. It is also sold as inexpensive hardwood timber, used for pallets and cheap plywood; more specialised uses include matches and the boxes in which camembert cheese is sold. Poplar wood is widely used in the snowboard industry for the snowboard "core", because it has exceptional flexibility.

Poplar was the most common wood used in Italy for panel paintings; the Mona Lisa and indeed most famous early renaissance Italian paintings are on poplar.

Due to its tannic acid content, the bark has been used in Europe for tanning leather.[3]

There has been some interest in using poplar as an energy crop for biofuel, particularly in light of its high energy in - energy out ratio, large carbon mitigation potential and fast growth.

Poplar wood also, particularly when seasoned, makes a good hearth for a bow drill. It was picked as the material for the bones of "Buster", the crash test dummy used in the TV show MythBusters, after some experiments revealed that it fractures under approximately the same loads as human bone. Poplar is sometimes used in the bodies of electric guitars and drums.

A folk tradition noted among Michigan miners in the early 20th century asserted that poplar wood was used to make the cross upon which Jesus Christ was crucified.[4]


Poplars and aspens are important food plants for the larvae of a large number of Lepidoptera species - see List of Lepidoptera that feed on poplars.

References
ISBN links support NWE through referral fees

[5]


[6] 2006

[3]

[7][8]

[8][9]

Credits

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  1. ↑ Note: the spelling is disputed; some sources use Aegiros, others use Aigeiros
  2. ↑ Poplar cultivation in Europe
  3. ↑ 3.0 3.1 Keeler, H. L. (1900). Our Native Trees and How to Identify Them. New York: Charles Scriber's Sons, 410-412. 
  4. ↑ (1900)Why the Poplar Stirs. Superstition of Miners in Michigan (in Notes and Queries). The Journal of American Folklore 13 (50): 226.
  5. ↑ Hamzeh, M., & Dayanandan, S. (2004). Phylogeny of Populus (Salicaceae) based on nucleotide sequences of chloroplast TRNT-TRNF region and nuclear rDNA. Amer. J. Bot. 91: 1398-1408. Available online
  6. ↑ Joint Genome Institute: Populus trichocarpa
  7. ↑ Meikle, R. D. (1984). Willows and Poplars of Great Britain and Ireland. BSBI Handbook No. 4. ISBN 0-901158-07-0.
  8. ↑ 8.0 8.1 Rushforth, K. (1999). Trees of Britain and Europe. Collins ISBN 0-00-220013-9.
  9. ↑ Eckenwalder, J. E. (1977). North American cottonwoods (Populus, Salicaceae) of sections Abaso and Aigeiros. J. Arnold Arbor. 58: 193-208.
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