rock elm Ulmaceae Ulmus thomasii Sarg.   symbol: ULTH
	Leaf: Alternate, simple, elliptical ovate, 2 1/2 to 4 inches in length, doubly serrated, base inequilateral, dark green and smooth above, paler and somewhat downy beneath. Flower: Monoecious; in short, tight hanging clusters, reddish-green in color, appearing in early spring before leaves. Fruit: Thin wafer-like samara, oval to obovate in shape, slightly pubescent, 1/2 inch long, mature in spring. Twig: Slender, zigzag, reddish brown, often (when rapidly growing) developing irregular corky ridges after a year or two; buds ovate, reddish brown, similar to American elm, but more slender. Bark: Deeply furrowed, flattened ridges, interlacing, grayish brown in color, similar to American elm but no conspicuous layers in bark cross sections. Form: Medium sized tree reaching heights of 70 to 80 feet with a narrower, more upright crown than American elm.
	USDAFS Silvics of North America - USDA Plants Database Ulmus thomasii is native to North America. Range may be expanded by planting. See states reporting rock elm (opens a new window).