Part 65

Growth Form: Large tree up to 80 feet tall; trunk diameter up to 4 feet; crown broadly rounded or sometimes flat-topped, usually with drooping branchlets.

Bark: Light or dark gray, furrowed, at maturity breaking into thin plates.

Twigs: Brown, slender, smooth or sparsely hairy, often zigzag; leaf scars alternate, half-round, each with 3 bundle traces.

Buds: Broadly ovoid, reddish-brown, smooth or sparsely hairy, up to one-fourth inch long.

Leaves: Alternate, simple; blades oval to elliptic, pointed at the tip, strongly asymmetrical at the base, up to 6 inches long and about half as wide, coarsely doubly toothed along the edges, the upper surface dark green and smooth, the lower surface pale and either softly hairy or smooth; leafstalks very short, usually yellow.

Flowers: In drooping clusters of 3-4, appearing before the leaves unfold, greenish-red, hairy, small.

Fruit: Oval, winged fruits up to one-half inch long, hairy along the edges, each wing notched at the top and surrounding a single central seed.

Wood: Heavy, strong, pale brown.

Uses: Flooring, farm implements, shipbuilding; frequently planted as an ornamental and as a shade tree, but greatly diminished in number by the Dutch Elm disease and phloem necrosis.

Habitat: Bottomland woods, along streams.

Range: Nova Scotia across to southern Manitoba, south to central Texas, east to south-central Florida.

Distinguishing Features: American Elm may be distinguished from the Winged Elm and the Rock Elm by its lack of corky wings on the branchlets. It differs from the Slippery Elm by its relatively smooth leaves and the lack of rusty-colored hairs on its buds. The Siberian Elm, which is also similar, does not have distinctly asymmetrical leaves. Hackberry leaves, which are also somewhat similar in appearance, have three main veins originating at the base of each leaf blade.

SIBERIAN ELM Ulmus pumila L.

Growth Form: Small tree to 35 feet tall; trunk diameter up to 1 foot; crown broadly rounded, with slender branchlets.

Bark: Gray or brown, shallowly furrowed at maturity.

Twigs: Slender, brown or grayish, smooth; leaf scars alternate, half-round, with 3 bundle traces.

Buds: Spherical, reddish-brown, up to ⅛ inch in diameter, somewhat hairy.

Leaves: Alternate, simple; blades short-pointed at the tip, tapering or rounded at the asymmetrical base, up to 7 cm long, up to half as broad, mostly singly toothed along the edges, smooth on both surfaces; leafstalks very short, usually smooth.

Flowers: In drooping clusters of 2-5, appearing before the leaves begin to unfold, greenish, small, without petals.

Fruit: Nearly round, winged fruits, up to ½ inch in diameter, not notched, smooth, 1-seeded.

Wood: Hard, heavy, pale brown.

Use: Grown chiefly as an ornamental and frequently reproducing around old buildings.

Habitat: Along roads, around buildings.

Range: Native of Asia; widely planted in the United States and naturalized from Minnesota to Kansas and eastward.

Distinguishing Features: The Siberian Elm is distinguished by its small, smooth, singly-toothed leaves.

SLIPPERY ELM Ulmus rubra Muhl.

Other Name: Red Elm.

Growth Form: Moderate tree up to 80 feet tall; trunk diameter up to 4 feet; crown broadly rounded or occasionally flat-topped.