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DescriptionThis tree is usually 30-40' tall at maturity (rarely up to 60' tall), consisting of a short trunk and a wide crown with ascending to widely spreading branches. The crown is usually somewhat open and irregular. On mature trees, the trunk is up to 1¼' across, consisting of flattened gray ridges and shallow reddish brown furrows. The twigs are light gray to reddish brown, more or less terete, with scattered small lenticels. Young shoots are light green, terete, and glabrous to minutely pubescent. Alternate compound leaves about ¾-1½' long occur along the twigs and young shoots. These leaves are either single-pinnate or partially bipinnate. Individual leaflets are usually 1½-4' long and 1-2½' across; they are lanceolate to ovate and either coarsely toothed or shallowly cleft. On bipinnate leaves, there are 1-2 pairs of secondary leaflets below some of the primary leaflets. These secondary leaflets are similar to the primary leaflets, except they are smaller in size and more narrow in shape. The upper leaflet surface is medium green and glabrous, while the lower leaflet surface is light green and either glabrous or minutely pubescent along the central vein. The leaflets usually have short petiolules (up to 1/8' long), although some leaflets may be sessile. The petiolules are light green to light yellow-green and glabrous to minutely pubescent. The central stalks (rachises) of the compound leaves are light green to red and glabrous to minutely pubescent. Twigs occasionally terminate in panicles of flowers about ¾-1½' long and at least one-half as much across. Each flower is about ½' across, consisting of 4 yellow petals, 4 green sepals, 8 stamens, and a pistil with a single style. While a flower is in bloom, the petals are widely spreading or recurved and they are narrowly lanceolate to lanceolate in shape. The sepals are lanceolate in shape and much shorter than the petals. At the base of each petal, there is a pair of small scale-like appendages that are yellow to orange-red. On the stamens, the lower halves of their filaments have long hairs. Both the style and the stamens are strongly exerted. On some trees, some of the flowers may be unisexual. The pedicels of the flowers are green and either glabrous or minutely pubescent. The peduncle and lateral stalks of each panicle are also green and either glabrous or minutely pubescent. The blooming period occurs during the summer (usually mid- to late summer in Illinois) for about 2-4 weeks. The flowers are mildly fragrant. Fertile flowers are replaced by inflated seedpods that become 1½-2½' long at maturity. These seedpods are obcordoid and strongly 3-lobed in shape; immature seedpods are light green to bright red, while mature seedpods are light brown to blackish brown. Each seedpod contains up to 3 seeds (1 seed per lobe). Individual seeds are globoid or globoid-ovoid in shape and 6-8 mm. in length. Because the seedpods are light-weight and inflated, they can be blown about by the wind or float on water. The root system is woody. This tree spreads by reseeding itself.