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 15–30 metres (49–98 ft) tall.
Populus sect. Populus
Populus is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar, aspen, and cottonwood.
Populus
Mature trembling aspen trees (Populus tremuloides) with young regeneration in foreground, in Fairbanks, Alaska
Male catkins of Populus × canadensis
The seeds of the poplar tree are easily dispersed by the wind, due to the fine hairs surrounding them.