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DescriptionThis medium-sized tree is 40-70' tall at maturity, forming a trunk up to 3½' across and a crown that is more or less ovoid. The relatively stout trunk can be straight or somewhat crooked, while the larger branches are ascending to widely spreading and rather crooked. On mature trees, trunk bark is gray-brown, rough-textured, and longitudinally furrowed between narrow scaly plates. The bark of larger branches is more gray and less rough-textured, while young twigs are brown to reddish brown, smooth, and hairless. Young twigs have scattered white lenticels (air pores) and depressed leaf scars. Leaves occur oppositely or in whorls of 3; they tend to hang downward from the twigs. The leaf blades are 6-12' long and 4-8' across; they are cordate to cordate-ovate in shape and smooth along their margins. Sometimes a leaf blade may have a pair of shallow obtuse lobes. The upper surface of the leaf blades is yellowish green, light green, or medium green and hairless (or nearly so), while the lower surface is more pale and short-pubescent. The petioles are 4-6' long, light green, and either hairless or mostly hairless. This tree produces erect pyramidal panicles of flowers about 4-12' tall and nearly as much across; there is typically 10-30 flowers per panicle. Individual flowers are 1½-2' across and 2-2½' long; each flower has a broad tubular corolla with 4-5 frilly lobes, a calyx that is deeply divided into 2 lobes, a 2-celled pistil with a white style, 2 long fertile stamens, and 3 short infertile stamens (staminodia). The corolla is bright white overall; it has purple-dotted lines and patches of bright yellow along the lower surface of its throat. The lobes of the calyx are oval-ovate, light green to purple, and either hairless or finely pubescent. The branching stalks of the panicle are green and hairless. The blooming period occurs from late spring to early summer, lasting about 2 weeks. Individual flowers remain in bloom for only a short time; they have a pleasant fragrance. Afterwards, fertile flowers are replaced by narrowly cylindrical seedpods that are 10-18' in length and about ½' across; they are either straight or slightly curved, and droop downward from short stalks. Immature seedpods are green, while mature seedpods are dark brown. During the fall and winter, the seedpods slowly divide into 2 parts, releasing their seeds. The seeds are arranged in conjoined pairs with outer fibrous wings; they are covered by a papery membrane that is light brown. Each pair of winged seeds is about 1-2' long and ¼' (or a little more) across. Individual seed bodies are about 5 mm. long and 4 mm. across, oval in shape, and flattened; their tips are well-rounded, rather than pointed. The pairs of winged seeds are very light and easily blown about by the wind. The root system is relatively shallow and spreading. The large deciduous leaves become pale yellow or pale greenish yellow during the autumn.