The common hoptree (Ptelea trifoliata) belongs to Rutaceae (the Citrus family). It is a small deciduous tree that is native to North America. This tree grows in alluvial thickets, rocky slopes, and up to a height of 6-8 m with a broad crown. The bark is reddish brown to gray brown, with short horizontal lenticels. The leaves are alternate and compound with three leaflets, dotted with oil glands. The leaflets are ovate or oblong, entire or serrate. The flowers are small, greenish white, and bloom in May and June. The fruit is a round wafer-like papery samara, and ripens in October.