Fraxinus nigra Marshall

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Common names:
black ash, black ash
Description:
Growth form:
Medium-sized tree,
Size:
12 - 20 m tall, trunk diameter 30 cm - 0.6 m.
Form
narrow and rounded with many stout, straight branches. Trunk often leaning or crooked, extending to the top of the crown.
Bark
ashy gray, thin, and fissured into soft, scaly plates that may flake off when rubbed.
Twigs
stout, dark green, becoming light gray then dark gray and warty. Leaf scars oval, with several bundle scars forming a U.
Buds
bluish black, small, conical, and finely hairy. Terminal bud 4 - 10 mm long and pointed. Uppermost pair of lateral buds up to 1 cm below the base of the terminal bud.
Leaves
opposite, pinnately compound, 25 - 40 cm long, with seven to eleven leaflets. Leaflets stalkless (except for the terminal), dark green above, paler and rusty-hairy along the veins beneath, 7 - 15 cm long, 2.5 - 5 cm wide, oblong to oblong lance-shaped with a tapering or rounded base and long-pointed tip, toothed, thin, and firm. Leaves turn reddish brown in autumn.
Flowers
either male, female, or bisexual. They are usually found on separate trees but sometimes they are found on the same tree (polygamodioecious). The elongated, branched inflorescence contains small purplish flowers that lack petals.
Fruit
dry, single-seeded, winged (samara), 2.5 - 4.5 cm long, oblong, and barely notched at the tip. Wing broad, often twisted, and extending to near the base of the flat seed cavity.
Help:
Plant Glossary
Similar species:
The other ash species of the Chicago Region look more or less similar to Fraxinus nigra. Fraxinus americana differs by having short-stalked leaflets with pale or whitish undersides, twigs with raised leaf scars, and a twig surface (except current year's growth) that is flaky, scaly, or peeling. Also, the wing of its fruit does not extend to the base of the large seed cavity. Fraxinus pennsylvanica sometimes has densely hairy shoots, and the wing of its fruit encloses half or more of the seed cavity. Fraxinus profunda has conspicuously stalked leaflets, densely hairy shoots (current), and the wing of its fruit often extends to the base of the seed cavity. Fraxinus quadrangulata has square twigs, and the wing of its fruit extends to and around the base of the seed cavity.
Flowering:
late April to June, before the leaves
Habitat and ecology:
Local in moist woods, swamps, fens, floodplains, and other mesic sites. However, its most characteristic habitat is on calcareous springy slopes.
Regional occurrence:
native
Notes:
The wood of Fraxinus nigra is used for baskets, barrel hoops, woven chair bottoms, fence posts, cabinets, interior finish, and furniture. The emerald ash borer (Agrilus planipennis) is a serious insect threat to all native ashes (see link below).
Etymology:
Fraxinus is the Latin word for ash. Nigra is Latin for black, referring to its dark brown heartwood.
vPlants
name code: FRNI ; page author: The Morton Arboretum ; page date: 2006-12-03
Further information (external links):
Google: Text Search Image Search
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References:
Barnes, B. V., and W. H. Wagner, Jr. 2004. Michigan trees: A guide to the trees of the Great Lakes region. Ann Arbor, MI: University of Michigan Press.
Little, E. L. 1980. National Audubon Society field guide to North American trees: Eastern region. New York: Alfred A. Knopf: Distributed by Random House.
Mohlenbrock, R. H. 1996. Forest trees of Illinois. 8th ed. Illinois: Illinois Department of Natural Resources, Division of Forest Resources.

Information provided on this page applies to the Chicago Region and may not be relevant or complete for other regions.

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