||There are 5 or 6 species of medium-sized to large trees in this genus, occurring from India to northern China and Australia. They include both evergreen tropical and deciduous cold-hardy species, one of the latter being the well known ?tree of heaven?. Their leaves are pinnate, mostly with a long midrib and many leaflets arranged in 2 regular rows. The flowers, of different sexes on different trees, are small and greenish yellow but borne in large stalked clusters in leaf axils toward tips of branches. They are followed by conspicuous clusters of flat, almost papery, elongated fruits with the single seed held in a neat little central bulge. The name Ailanthus is taken from the Moluccan name ?ailanto? for Ailanthus moluccana, meaning ?sky tree?, which reputedly inspired the common name ?tree of heaven? (though for a different species).
||CULTIVATION: Easily cultivated if their respective climatic requirements are met, they make fast growth when young. In the case of ?tree of heaven?, the greater problem often is keeping its spread in check. Propagation is from seed (which may need cold stratification) or root cuttings.