Populus is a genus of between 25–35 species of 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. They are medium-sized to large or very large deciduous trees growing to 15–50 m tall, with trunks up to 2.5 m 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… (More on Poplars)