It is a large deciduous tree growing to 20-35 m (exceptionally to 46 m) tall with a trunk up to 2 m (exceptionally to 3.5 m) diameter, with a tall, domed crown. The bark is smooth and pale grey on young trees, becoming thick and vertically fissured on old trees. The shoots are stout, greenish-grey, with jet black buds .
The leaves are 20-35 cm long, pinnate compound, with 7-13 leaflets , the leaflets 3-12 cm long and 0.8-3 cm broad, sessile on the leaf rachis, and with a serrated margin. The leaves are often among the last to open in spring, and the first to fall in autumn if an early frost strikes; they have no marked autumn colour, often falling dull green.
The flowers open before the leaves, the female flowers being somewhat longer than the male flowers; they are dark purple, and without petals, and are wind-pollinated.