Shrub, occasionally a small tree to 7.5 m, trunk to 20 cm in diameter Leaves: alternate, stalked, with three leaflets (trifoliate). Flowers: male, female and bisexual on the same plant, usually all in the same stalked cluster, each with three to five greenish white petals. Fruit: a winged seed (samara), 2 - 2.5 cm wide, yellowish green changing to brown, flattened and rounded, resembling a wafer, borne in hanging clusters that persist into winter. Bark: gray to brown and slightly rough, developing cracks with age. Twigs: yellowish green to reddish brown, warty, sometimes hairy. Buds: light brown, tiny, spherical, wooly. Leaf scars: large and horseshoe-shaped. Leaflets: dark green above, paler and sometimes hairy beneath, 10 - 15 cm long, 5 - 10 cm wide, egg-shaped with a pointed tip, non-toothed or finely toothed. Odor: unpleasant, released when crushing the leaves, twigs and fruit.
Similar species: Ptelea trifoliata ssp. trifoliata is represented by two varieties in the Chicago Region. See links below for further information. The leaves of this shrub resemble those of Toxicodendron radicans (poison ivy) and Staphylea trifolia (bladdernut). Toxicodendron radicans is a vine that has alternate leaves with non-toothed and sometimes lobed margins. Staphylea trifolia has opposite leaves with sharply and irregularly toothed margins and a long-stalked center leaflet.
Notes: Specimens mapped and linked at right are those that were not designated a variety name.