Environment Planet Earth Identify the North American Poplars Here's how to pinpoint trees in the willow family (Salicaceae) By Steve Nix Steve Nix Writer University of Georgia Steve Nix is a member of the Society of American Foresters and a former forest resources analyst for the state of Alabama. Learn about our editorial process Updated January 15, 2018 (Rob Atkins/Photographer's Choice RF/Getty Images) Share Twitter Pinterest Email Planet Earth Outdoors Weather Conservation The genus Populus' most common North American natives include one true poplar in the north, four primary species of cottonwoods and the quaking aspen. Most of the known 35 natural poplar species live in the Northern Hemisphere. The cottonwoods thrive in an ecosystem associated with riparian and wetland areas in eastern and western North America. The aspens are most comfortable in boreal environments dominated by conifers with aspen being a major broad-leaved species. Balsam poplar (Populus balsamifera) is the northernmost American hardwood and a major deciduous tree in Canada and Alaska. The Common North American Poplar Species Quaking aspen Balsam poplar Eastern cottonwood Black cottonwood All have long reproductive catkins that appear just before the new leaves of spring and can help in identification. The resulting fruit is a capsule that opens into 2 tp 4 parts. The tufted seeds are shed in masses of white "cotton" which can cover the ground inches deep. The leaves of aspen and Eastern cottonwood are deltoids where black cottonwood and balsam poplar are ovate. They occur on a branch alternately, are simple (single leaf) and mostly toothed. Interesting Facts The Eastern Cottonwood, Populus deltoides, is one of the largest North American hardwood trees. The aspen has the widest range in the United States. It occurs throughout the eastern United States and throughout Canada.Yellow poplar is not a true poplar and not listed here.