Acer negundo L.

Acer: Ancient Latin name for maple

negundo: from "nurgundi" (Sanskrit), an Indian tree with similar leaves

Habit: Deciduous, dioecious tree up to 15-20 m tall.

Leaves: opposite, deciduous, compound, petiolate; blade imparipinnate, with 3-7 leaflets; leaflets 5-10 cm long, elliptic, ovate or obovate, irregularly dentate to lobulate, acuminate towards the apex, pubescent abaxially.

Flowers: proteranthous, unisexual, small, greenish, not showy, apetalous, with a 4-lobed gamosepalous calyx, arranged in hanging inflorescences with long peduncles; male flowers in cymose fascicles, with 4 hanging stamens; female flowers hypogynous, arranged in racemes, with a syncarpous, 2-carpellate gynoecium with a superior ovary.

Fruit: double samara; wings spreading at a narrow angle, parallel to slightly divergent, narrow towards the base.

The species flowers at the end of winter or beginning of spring, before the leaves sprout; fruits mature at the end of summer.

Native to the E United States. Naturalized in Spain.

Among the various species of maples that grow spontaneously or are cultivated in the Iberian Peninsula, this is the only one with compound leaves. The common name of this maple refers to the similarity between its leaves and those of the ash (Fraxinus excelsior L.), which it could be confused with. However, they are easy to distinguish by looking at the leaf rachis, which is smooth in the maple and grooved in the ash.

It is widely used as an ornamental in streets and parks in most of the world. There has been limited use of the species in its native region to extract its sap, which is rich in sugars but yields sugar of a lower quality and in smaller amounts than that of A. saccharum Marshall, the sugar maple, also native to E North America and used to obtain sugar and syrup. Its timber is used to manufacture pianos and decorative panelling.

It is easily propagated from seeds, which can even germinate spontaneously.