Ulmus (genus) en

Genus containing around18 species of forest, timber, and ornamental shade trees native primarily to North Temperate areas. Many are cultivated for their height and attractive foliage. Prior to the industrial revolution, elms were also used as water pipes and in water pumps in large cities because they are durable in water. From 1925 to the mid 20th century, many of the native European and North American elms were killed by the Dutch elm disease. These trees are now being replaced by the disease resistant Chinese elm. Elm leaves are doubly toothed and often lopsided at the base. The petalless flowers appear before the leaves and are borne in clusters on jointed stems. The nutlike fruit, surrounded by a flat, sometimes hairy, winglike structure, is called a samara.