Trees or small trees. Branchlets pubescent, with a pith. Leaves alternate, pinnate; leaflets 13-41, opposite or nearly so; blades papery or thinly leathery, base oblique, margin entire or serrate, apex acuminate, base sometimes 1- or 2-dentate on either side, teeth glandular abaxially at apex. Flowers small, polygamo-dioecious, in axillary or terminal thyrses. Sepals 5, imbricate. Petals 5, valvate. Disk 10-lobed. Stamens 10, inserted at base of disk, undeveloped or rudimentary in pistillate flowers. Carpels 2-5, free or slightly connate only at base; ovules 1 or 2 per locule, campylotropous or anatropous; styles 2-5, connate, but only with female trace in male flowers. Samarium oblong-elliptic, with a seed surrounded by wing. Seed flat, rounded, obovate or slightly deltoid, with some endosperm or without; endocarp thin; cotyledons compressed.
"Incompletely dioecious; fls 5-merous; stamens 10 (fewer or none on fls of female trees); carpels 2–5, united at the axis only, each with a single ovule, maturing into separate samaras with the seed near the center; trees with pinnately compound lvs and malodorous fls in large terminal panicles. 10, Old World."