Medium-sized tree, height 30' to 50' (taller under very favorable conditions), may reach a diameter of up to 16"; slender, spreading, somewhat drooping branches form a broad, open, rather flat-topped head that resembles a great green plume; trunk often divided near the ground.
Dark gray or brown on old trees; divided into thin, tight scales; strong, brown, straight, sharp, shiny thorns appear on one-year-old wood and remain for many years.
Alternate on stem, 6" to 8" long, doubly compound (featherlike) with 18 to 28 small egg-shaped leaflets that have finely toothed margins; dark green and lustrous above and dull yellow-green below, turning yellow in the autumn.
A pod, length 10" to 18"; flat dark brown or black when ripe, containing seeds and yellow whitish pulp; pod often becomes twisted as seeds ripen; seeds are hard and each is separated from the others by the pulp; pods are eaten by many animals.
Occurs in scattered stands or as individual trees, especially in southern Minnesota in counties along the Root River Valley and Mississippi bottomlands; found in forested areas, but is more common in disturbed and barren areas beside roads and fields; shade intolerant, fast growing.