Fraxinus angustifolia, the narrow-leafed ash, is a species of Fraxinus native to central and southern Europe, northwest Africa, and southwest Asia.[
It is a medium-sized deciduous tree growing to 20–30 m tall with a trunk up to 1.5 m diameter. The bark is smooth and pale grey on young trees, becoming square-cracked and knobbly on old trees. The buds are pale brown, which readily distinguishes it from the related Fraxinus excelsior (black buds) even in winter. The leaves are in opposite pairs or whorls of three, pinnate, 15–25 cm long, with 3–13 leaflets; the leaflets being distinctively slender, 3–8 cm long and 1–1.5 cm broad. The flowers are produced in inflorescences which can be male, hermaphrodite or mixed male and hermaphrodite. The male and hermaphrodite flowers occur on all individuals, i.e. all trees are functionally hermaphrodite. Flowering occurs in early spring. The fruit when fully formed is a samara 3–4 cm long, the seed 1.5–2 cm long with a pale brown wing 1.5–2 cm long.The older stems are greyish in colour and the bark on the main trunk can become quite rough and fissured with age. Younger stems are greenish-brown or yellowish, hairless (i.e. glabrous), and with small whitish spots (i.e. lenticels). The growing buds at the tips of the branches are dark brown and hairless.The inconspicuous flowers appear in late winter or early spring when the tree is still leafless. They are borne in dense branched clusters above the old leaf scars (i.e. in axillary panicles). These clusters can contain only male flowers, only bisexual flowers, or a mixture of male and bisexual flowers. However, all trees have at least some male and some bisexual flowers. Invasive in the southern United States.