Ulmus

Ulmus is a genus of deciduous and semi-evergreen trees in the family Ulmaceae. The genus first appeared in the Miocene geological period about 20 million years ago, originating in what is now central Asia. These trees are commonly known as elms.

Description

Elms are hermaphroditic, having perfect flowers, and can self-pollinate. However, they are predominantly outcrossing due to the flowers having different maturation times. This process is aided by the wind. Seed dispersal is by wind and water. Elms can form root sprouts, as well as suckers, from the roots.

Species

There are about 30 to 40 species of Ulmus. The classification is still not fully resolved, but it is generally accepted that there are three main species groups, the Ulmus, Felderae, and Microptelea sections.

Uses

Elms are loved for their graceful, stately shape, with branches like spreading fountains, and their green leaves that turn gold in fall. They are also valued for their wood, which is used for furniture and boxes. In addition, they are often planted as ornamental trees because of their resistance to pollution and their ability to form a dense canopy.

Diseases

Elms are susceptible to a number of diseases, including the devastating Dutch elm disease, which has destroyed many of the elms in Europe and North America. They are also vulnerable to elm yellows, elm phloem necrosis, and canker.

Conservation

Efforts to conserve the genetic diversity of Ulmus species are ongoing. These efforts are particularly important in light of the threats posed by Dutch elm disease and other pathogens.

See also

• List of Elm species and varieties
• Elm cultivars, hybrids and hybrid cultivars
• Elm leaf beetle
• Elm seed bug
• Elm yellows
• Dutch elm disease

Ulmus Resources
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