Fraxinus L.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1972, Flora Europaea. Volume 3. Diapensiacea to Myoporaceae, Cambridge: Cambridge University Press : 53

4. Fraxinus L. 2

Deciduous trees. Twigs flattened at the nodes. Leaves opposite or sometimes in whorls of 3, imparipinnate, rarely reduced to one leaflet. Flowers hermaphrodite or unisexual, small, in terminal or axillary panicles. Calyx campanulate and 4-lobed, or absent. Corolla usually absent; when present with 2-6 more or less free petals; stamens hypogynous; stigmas 2. Fruit a samara, winged distally.

The leaves vary greatly from young to adult plants; in the juvenile stage they commonly bear a larger number of smaller, rounded and more coarsely toothed leaflets; the first leaves of the seedlings are simple.

1 Corolla present; panicles terminal or axillary on leafy twigs 1. ornus 1 Corolla absent; panicles axillary, appearing before the leaves 2 Leaflets distinctly petiolulate; calyx present; body of samara terete 2. pennsylvanica 2 Leaflets sessile or subsessile; calyx absent; body of samara flattened 3 Buds black; leaflets with more serrations than lateral veins 3. excelsior 3 Buds brown; leaflets usually with as many serrations as lateral veins 4 Twigs and leaf-rhachis glabrous 4. angustifolia 4 Twigs and leaf-rhachis densely pubescent 5. pallisiae