A tree 60 to 70, occasionally over 100 ft high; branchlets square and distinctly four-winged, not downy; bark of the trunk covered with loose plates. Leaves 7 to 14 in. long, with five to eleven leaflets, which are ovate to lanceolate, 3 to 5 in. long, 1 to 2 in. wide, rounded or broadly wedge-shaped and unequal at the base, tapering at the apex to a long, slender point, sharply toothed, yellowish green and glabrous above, paler and downy beneath, especially about the midrib and veins. Common stalk minutely downy, and grooved on the upper side; stalks of leaflets 1⁄8 to 1⁄4 in. long. Flowers in short panicles from the previous year’s wood, calyx minute, soon deciduous. Fruit, 11⁄2 in. long, 5⁄16 in. wide, oblong, with a notch at the apex.
Native of the south-eastern and central United States; introduced in 1823. It produces a valuable timber in the United States, but does not seem to have ever attained any great size in this country. There is a small specimen in the Ash collection at Kew. It is readily distinguished from all ashes with the same number of leaflets by its square, winged branchlets, except F. griffithii, and that has untoothed leaflets, and belongs to the Ornus section.