elm(redirected from American elm)
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elm,common name for the Ulmaceae, a family of trees and shrubs chiefly of the Northern Hemisphere. Elm trees (genus Ulmus) have a limited use as hardwoods for timber, especially the rock or cork elm (U. thomasi). Tall and graceful, with fan-shaped crowns of finely subdividing branches and twigs, elms are widely planted as ornamental and shade trees, chiefly the American, or white, elm (U. americana) and the English, or Wych, elm (U. campestris) of N and central Europe and W Asia. Tolerant of urban conditions, both species are among those plants attacked by the fungus known as Dutch elm disease (see fungal infectionfungal infection,
infection caused by a fungus (see Fungi), some affecting animals, others plants. Fungal Infections of Human and Animals
Many fungal infections, or mycoses, of humans and animals affect only the outer layers of skin, and although they are sometimes
..... Click the link for more information. ), but disease-tolerant varieties have been propagated. The mucilaginous inner bark of the slippery elm (U. fulva) is used medicinally in cough drops. Some species of the genus Celtis (the hackberries of America and the nettle trees of the Old World) are cultivated for their edible fruit. False sandalwood (Planera aquatica) is a member of the elm family; its fragrant wood is used in cabinetmaking. The elm family is classified in the division MagnoliophytaMagnoliophyta
, division of the plant kingdom consisting of those organisms commonly called the flowering plants, or angiosperms. The angiosperms have leaves, stems, and roots, and vascular, or conducting, tissue (xylem and phloem).
..... Click the link for more information. , class Magnoliopsida, order Urticales.
several species of plants from the genus Ulmus of the family Ulmaceae. The trees are deciduous and blossom in early spring before the leaves appear.
The best-known elm in Europe is the Russian elm (Ulmus laevis), a tree up to 35 m tall with fruits (key-fruits) on long peduncles. In the USSR the elm usually grows in broad-leaved forests. Along the floodlands of rivers and the shores of lakes it advances on the north to the taiga, to 63° N lat.; on the south it extends to the semidesert of the Caspian region. The tree is long-lived, frost-resistant, and grows in fertile soils that are sufficiently moist. Elms are used in city landscaping and in plantings around bodies of water. The Siberian elm (U. pumila) is a small tree with small, naked, sessile key-fruits; when cultivated, it reaches a height of 27 m. It is a variety suitable for open spaces, as it is quick-growing, drought-resistant, and salt-resistant; in addition, it is not subject to Dutch elm disease. The Siberian elm grows in the arid regions of Asia, in southern Europe, North America, and Argentina. It is used in protective plantings and in city landscaping. Bigfruit elm (U. macrocarpa) is a low tree with downy, large (up to 4 cm) sessile key-fruits. Corklike excrescences often form on the branches. Bigfruit elm usually migrates by means of root offshoots. It grows among rocks and in the scree along rivers. It can be used in antierosion plantings. The Siberian elm and bigfruit elm are Asian species, growing wild in the Baikal region, in the Far East, in Mongolia, China, and on the Korean Peninsula. Karagach (U. dens a) is grown in Middle Asia and Transcaucasia. The wood of all elms is used in the construction and furniture industries.
I. A. GRUDZINSKAIA
(Ulmus), a genus of deciduous, more rarely evergreen, trees of the family Ulmaceae. Height, up to 40 m; diameter, up to 2 m. The leaves are alternate, simple, and biserrate. The flowers are monoecious and small, usually gathered into bundles or capitula. The fruits are dry flattened achenes, often alate.
Elms blossom in early spring, before the leaves appear; the fruit usually ripens in May. Some American and Chinese species blossom and produce fruit in autumn.
There are more than 30 species of Ulmus in the temperate, and less often the torrid, zones of the northern hemisphere. In the USSR there are ten species in the European part, the Caucasus, Kazakhstan, Transbaikalia, Middle Asia, and Far East, including U. glabra, U. japonica, and U. laciniata. They are all frost-resistant and require dampness and fertile soil. Many species are used as greenery and in protective forestry. The wood is used in construction and the furniture industry; in India and Tibet the leaves and young branches are used to feed cattle.