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: Species is 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.
Looks like: winged elm - cedar elm - American elm - slippery elm
Additional Range Information: See the full-size PDF map.
More Information: Wood
External Links: USDAFS Silvics of North America - USDA Plants Database - USDAFS Forest Products Lab
All material © 2019 Virginia Tech Dept. of Forest Resources and Environmental Conservation; Photos and text by: John Seiler, Edward Jensen, Alex Niemiera, and John Peterson; Silvics reprinted from Ag Handbook 654; range map source information