Populus's a genus of between 25–35 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. The genus has a large genetic diversity, and can grow from anywhere between 15–50 m tall, with trunks of up to 2.5 m diameter. The bark on young trees's smooth, white to greenish or dark grey, often with conspicuous lenticels; on old trees it remains… (More on Poplars)