Box elder (Acer negundo) is a native of the eastern side of North America but is widely planted in Europe and occasionally naturalised. It is one of the maples, which as a group are distinguished by their fruits, each consisting of two single-seeded, winged segments. Box Elder differs from most other maples in its pinnate leaves, not disimilar to those of an Ash. It is very fast-growing.
Trees and shrubs of the Mediterranean by Helge Vedel, translated from the Danish by Aubrey Rush (Penguin Guides, 1978), p.78.