Elms are deciduous and semi-deciduous trees comprising the genus Ulmus, family Ulmaceae. Elms first appeared in the Miocene period about 40 million years ago. Originating in central Asia, the tree flourished and established itself over most of the Northern Hemisphere, including North America. Eight elm species are endemic to North America, and a smaller number to Europe; the greatest diversity is found in China.
The Common North American Elm Species
Leaves: alternate, asymmetrical, uneven at base, toothed.
Fruit: a drupe or winged key.