Distribution: Occurring mostly east of the Cascades in Washington, but also in scattered localities west of the Cascades; widely distributed throughout North America.
Habitat: Escaped ornamental in roadsides, waste areas, along railroad tracks, and other open, disturbed areas.
Origin: Introduced from China
Conservation Status: Not of concern
Large, fast-growing, smooth-barked, sub-dioecious trees.
Leaves very large, alternate, pinnate, deciduous, glabrous or puberulent; leaflets 10-25, the terminal one often absent, lance-ovate, 4-15 cm. long, with 1-3 coarse, rounded teeth on each side near the base, each tooth bearing a gland on the lower side.
Inflorescence a large, open panicle; flowers small, greenish, 6-8 mm. broad, ill-scented; sepals 5, persistent; petals 5, deciduous; stamens 10 on the perfect and staminate flowers.
Samaras 2.5-5 cm. long, spirally twisted.