Description from Flora of China
Trees or shrubs, deciduous. Winter buds enclosed by scales. Leaves alternate; stipules absent; leaf blade margin serrate. Flowers fasciculate or in short racemes at nodes of one year old branchlets. Pedicel slender, jointed. Flowers opening before leaves. Calyx tube obconical, adnate to ovary, 4-ribbed expanding in fruit; teeth 4, short. Corolla campanulate; lobes 4(or 5), imbricate, base shortly connate. Stamens 8--16, in 1 series, almost separate from petals, basally slightly connate; anthers oblong. Ovary often inferior, 2--4-locular; ovules 4 per locule, basally pendulous, apically ascending, placentation axile. Style elongated; stigma 4-lobed. Drupes almost dry, 2--4-winged, indehiscent, apex with persistent calyx teeth and style base forming a beak. Seeds oblong, terete; seed coat crusty; cotyledons oblong.
Five species: E North America, China; one species in China.