Cottonwood (Populus deltoides var. occidentalis)
Large tree, 50' to 80' tall, diameter 36" to over 48"; developing first a narrow, conical crown that with maturity becomes broad and open supported by a massive trunk.
Light gray on young trees and dark gray and rough on older trees.
Simple, alternate on stem, 3" to 5" long, nearly as wide; broadly ovate or triangular, pointed, square at base, finely toothed or wavy on edges; covered with soft white hairs on underside; slender stems from 2" to 3" long are flattened; winter buds covered with chestnut brown, resinous scales; turns yellow to yellowish orange in autumn.
Two to four valved, thin capsules borne on short stock in drooping "catkins"; seeds, when set free in late May or June, are minute, pale, brownish white, enclosed in a cluster of white cottony hairs that carry them for long distances. There are two kinds of flowers borne separately on different trees; female trees throw cotton.
Found throughout Minnesota, often forming extensive groves; will grow on dry locations but makes most rapid progress on moist sites; shade intolerant, very fast-growing.