Shrubs , spreading to compact, to 10 m. Bark smooth; lenticels scattered, conspicuous to inconspicuous, small, mostly unenlarged. Winter buds nearly sessile, ovoid, apex acuminate; stalks usually not over 1 mm; scales 4--6, unequal, imbricate. Leaf blade broadly to narrowly ovate or elliptic, 3--11 × 3--8 cm, base rounded, obtuse, or cuneate, sometimes nearly cordate, margins serrulate to coarsely doubly serrate, apex acute to rounded; surfaces abaxially glabrous to tomentose, lightly to heavily resin-coated. Inflorescences: staminate catkins in 1 cluster of 2--4, formed late in growing season before flowering and exposed during winter; pistillate catkins in 1 or more clusters of 2--10, formed season before blooming, enclosed in buds during winter, exposed with new growth in spring. Flowering with new growth in spring. Infructescences ovoid to ellipsoid or nearly cylindric; peduncles relatively long, thin. Samaras elliptic to obovate, wings wider than body, membranaceous.