Poison Sumac

This shrub is 10-25' tall, consisting of a trunk up to 6" across and a relatively open crown. Trunk bark is light gray and relatively smooth, except for scattered lenticels that resemble small bumps. Branch bark is also light gray and more smooth, while twigs are orange, tan, or brown and usually glabrous (less often pubescent); twigs have numerous small lenticels and prominent terminal buds that are purplish red. Alternate compound leaves occur along the twigs; these leaves are 6-14" long and odd-pinnate with 7-13 leaflets. Petioles and rachises of the compound leaves are red to yellowish red and glabrous. Individual leaflets are 2-4" long and 1-1¾" across; they are ovate or oblong-ovate and smooth along their margins. The petiolules (basal stalklets) of the leaflets are up to ¼" long and usually bright red. The upper surface of the leaf blades is medium to dark green and glabrous, while the lower surface is pale green and usually glabrous (less often sparsely pubescent). During the fall, the deciduous leaflets turn orange or red.

Because Poison Sumac is usually dioecious, the same shrub produces either all male (staminate) or all female (pistillate) flowers. Less often, both male and female flowers are produced on the same shrub, while other shrubs produce perfect flowers. The flowers are produce in panicles from the axils of the compound leaves; individual panicles are up to 8" long and 4" across. The peduncles and petioles of these panicles are glabrous or finely pubescent. Individual flowers are about 1/8" (3 mm.) across, consisting of a short green calyx with 5 teeth and 5 green or greenish yellow petals. Each male flower has 5 stamens, each female flower has a pistil with a single style, while a perfect flower has both a pistil and 5 stamens. The filaments of the stamens are white, while their anthers are yellow. The blooming period occurs from late spring to early summer for about 2 weeks. Fertile female and perfect flowers are replaced by one-seeded drupes during the summer. Individual drupes are about ¼" across, globoid to ovoid in shape, and glabrous. They are initially green, but become white or grayish white at maturity. The panicles of drupes have a tendency to droop downward; they can persist on the shrub through the winter. This shrub has a tendency to form vegetative sprouts from the base.