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''Populus'' section ''Populus'', of the ''Populus'' (poplar) genus, includes the aspen trees and the white poplar ''Populus alba''. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by contrast, is native to warmer regions, with hot, dry summers. These trees are all medium-sized deciduous trees ranging tall. All of the species in section ''Populus'' typically grow in large clonal colonies derived from a single seedling, and spreading by means of root suckers; new stems in the colony may appear at up to 30–40 metres from the previous trees. Each individual tree can live for 40–150 years above ground, but the root system of the colony is long-lived, sending up new trunks as the older trunks die off above ground, spreading about a metre per year, sometimes eventually covering many hectares. They are able to survive forest fires because the roots are below the heat of the fire, and new sprouts can grow from the roots. One such colony of American aspen (''P. tremuloides'') in Utah, given the nickname of "Pando", is estimated to be 80,000 years old, making it possibly the oldest living colony of aspens. == Species == Some of the species in the section are:〔(【引用サイトリンク】 ''Populus'' Sect. ''Populus'' )〕 *''Populus alba'': white poplar (northwest Africa, southern Europe, east to central Asia) *''Populus adenopoda'': Chinese aspen〔(【引用サイトリンク】publisher=USDA GRIN taxonomy )〕 (China, south of ''P. tremula'') *''Populus davidiana'' *''Populus grandidentata'': bigtooth aspen (eastern North America, south of ''P. tremuloides'') *''Populus ningshanica'' *''Populus qiongdaoensis'' *''Populus rotundifolia'' *''Populus sieboldii'': Japanese aspen〔(【引用サイトリンク】publisher=USDA GRIN taxonomy )〕 (Japan) *''Populus tomentosa'', Chinese white poplar〔(【引用サイトリンク】publisher=USDA GRIN taxonomy )〕 (China) *''Populus tremula'': Eurasian aspen (northern Europe and Asia) *''Populus tremuloides'': American aspen (northern and western North America) *''Populus wulianensis'' Natural hybrids between species in the section include: *''Populus'' × ''canescens'': grey poplar,〔(【引用サイトリンク】publisher=USDA GRIN taxonomy )〕 ''P. alba'' × ''P. tremula'' *''Populus'' × ''hopeiensis'': ''P. davidiana'' × ''P. tomentosa'' *''Populus'' × ''pseudotomentosa'': ''P. adenopoda'' × ''P. tomentosa'' 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Populus sect. Populus」の詳細全文を読む スポンサード リンク
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