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.
Author: The Morton Arboretum
From Flora of Indiana (1940) by Charles C. Deam
An infrequent shrub in all parts of the state. It is usually restricted to the alluvial banks of streams but it is found sometimes on the tops and slopes of rocky bluffs. The under surface of the leaflets is more or less pubescent on unfolding, becoming more or less glabrous at maturity. Some are glabrous with the exception of a few hairs in the axils of the veins and on the petioles; others have a straggling pubescence; and in nearly a fourth of our specimens the under surface is thickly pubescent. The pedicels of the flowers are likewise more or less densely pubescent at flowering time, and at maturity they become glabrous or remain more or less densely pubescent. There is no correlation of pubescence of the leaflets and pedicels, although the leaflets that are very pubescent at maturity also have pubescent pedicels, but nearly glabrous leaflets may have densely pubescent pedicels. Plants with leaflets remaining pubescent until maturity are Ptelea trifoliata f. pubescens (Pursh) Fern. (Rhodora 38: 233. 1936). The pubescent form is much less frequent than the glabrate form and has no definite geographic range in Indiana, although most of our specimens are from the southern part of the state.