The members of the genus are possessed of the following characters: - Bark often papyraceous; leaves deciduous, compound, alternate and imparipinnate, with leaflets serrate or entire; flowers in racemes or panicles, white, green, yellowish or pink, having a.
Thus we may have a group of racemes, arranged in a racemose manner on a common axis, forming a raceme of racemes or compound raceme, as in Astilbe.
In the privet (Ligustrum vulgare) there are numerous racemes of dichasia arranged in a racemose manner along an axis; the whole inflorescence thus has an appearance not unlike a bunch of grapes, and has been called a thyrsus.
The spikelets are usually many-flowered and variously arranged in racemes or panicles.
The flowers are in fascicles, appearing before the leaves as in the Norway maple, or in racemes or panicles appearing with, or later than, the leaves as in sycamore.