Ulmus glaucescens
Encyclopedia
Ulmus glaucescens Franch. the Gansu Elm, is a small deciduous
tree from the northern provinces of China
, where it is found along river valleys and on mountain slopes at elevations of between 2000 m and 2600 m .
. The bark is longitudinally fissured and occasionally exhibits a peeling, mottled pattern. However, the tree is most easily distinguished by its small leaves; ranging from ovate
to lanceolate
, their size rarely exceeds 5 cm in length by 2.5 cm breadth, and are borne on twigs devoid of corky wings or layers. The perfect wind-pollinated apetalous flowers are produced on second-year shoots in March - April; the samarae
are elliptic, < 25 mm long, and can remain on the tree until the end of May.
; it is also very resistant to the Elm Leaf Beetle Xanthogaleruca luteola
.
. Like most other Asiatic species, it is intolerant of wet ground. The tree is very rare in cultivation, but was one of a number of Chinese elms assessed for their horticultural potential at the Morton Arboretum
, Illinois
, during the last quarter of the 20 th century . It is not known to have been introduced to Europe
or Australasia
. There are no known cultivar
s of this taxon, nor is it known to be in commerce.
Rehder, and var. lasiocarpa
L.K.Fu.
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
tree from the northern provinces of China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, where it is found along river valleys and on mountain slopes at elevations of between 2000 m and 2600 m .
Description
Although typically no more than 10 m in height, it can sometimes reach 18 m. Slow growing, the tree is possessed of a stiff branching pattern resembling that of a young American ElmAmerican Elm
Ulmus americana, generally known as the American Elm or, less commonly, as the White Elm or Water Elm, is a species native to eastern North America, occurring from Nova Scotia west to Alberta and Montana, and south to Florida and central Texas. The American elm is an extremely hardy tree that can...
. The bark is longitudinally fissured and occasionally exhibits a peeling, mottled pattern. However, the tree is most easily distinguished by its small leaves; ranging from ovate
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
to lanceolate
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
, their size rarely exceeds 5 cm in length by 2.5 cm breadth, and are borne on twigs devoid of corky wings or layers. The perfect wind-pollinated apetalous flowers are produced on second-year shoots in March - April; the samarae
Samara (fruit)
A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...
are elliptic, < 25 mm long, and can remain on the tree until the end of May.
Pests and diseases
The tree is resistant to Dutch elm diseaseDutch elm disease
Dutch elm disease is a disease caused by a member of the sac fungi category, affecting elm trees which is spread by the elm bark beetle. Although believed to be originally native to Asia, the disease has been accidentally introduced into America and Europe, where it has devastated native...
; it is also very resistant to the Elm Leaf Beetle Xanthogaleruca luteola
Xanthogaleruca luteola
Xanthogaleruca luteola, commonly known as the Elm Leaf Beetle, is a serious pest of the elm. Indigenous to Europe, it was accidentally introduced to North America. Both the imagines and larvae feed on the emergent leaves of the elm...
.
Cultivation
The tree is notable for its resistance to extreme drought which, combined with its high resistance to the elm leaf beetle in the USA, has made it a contender for establishment on the Great PlainsGreat Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
. Like most other Asiatic species, it is intolerant of wet ground. The tree is very rare in cultivation, but was one of a number of Chinese elms assessed for their horticultural potential at the Morton Arboretum
Morton Arboretum
The Morton Arboretum, in Lisle, Illinois, covers 1,700 acres and is made up of gardens of various plant types and collections of trees from specific taxonomical and geographical areas. It includes native woodlands and a restored Illinois prairie. The Arboretum has over 4,100 different species of...
, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, during the last quarter of the 20 th century . It is not known to have been introduced to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
or Australasia
Australasia
Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean. The term was coined by Charles de Brosses in Histoire des navigations aux terres australes...
. There are no known cultivar
Cultivar
A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...
s of this taxon, nor is it known to be in commerce.
Subspecies & varieties
Two varieties are recognized: var. glaucescensUlmus glaucescens var. glaucescens
Ulmus glaucescens var. glaucescens L. K. Fu is endemic to mountain slopes at between 2000 m - 2400 m in the provinces of Gansu, Hebei, Henan, Liaoning, Nei Mongol, Ningxia, eastern Qinghai, Shaanxi, Shandong, and Shanxi.-Description:...
Rehder, and var. lasiocarpa
Ulmus glaucescens var. lasiocarpa
Ulmus glaucescens var. lasiocarpa Rehder, named the Hairy-fruited Glaucescent Elm in the USA, is found along rivers and mountain slopes at elevations between 2500 m - 2600 m in the provinces of Hebei, Henan, Liaoning, Nei Mongol, Ningxia, eastern Qinghai, and Shanxi.-Description:The variety is...
L.K.Fu.
Accessions
North America- Brenton ArboretumBrenton ArboretumThe Brenton Arboretum 121 acres is a new arboretum and botanical garden in early stages of development, located at 2629 Palo Circle, Dallas Center, Iowa, USA. The Arboretum aims to display all Iowa native trees and shrubs suitable to the site, as well as many other tree species which can grow in...
, Dallas Center, IowaIowaIowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...
. No accession details available. - Morton ArboretumMorton ArboretumThe Morton Arboretum, in Lisle, Illinois, covers 1,700 acres and is made up of gardens of various plant types and collections of trees from specific taxonomical and geographical areas. It includes native woodlands and a restored Illinois prairie. The Arboretum has over 4,100 different species of...
, IllinoisIllinoisIllinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
. No accession details available. - U S National ArboretumUnited States National ArboretumThe United States National Arboretum is an arboretum in Washington, D.C., operated by the United States Department of Agriculture's Agricultural Research Service as a division of the Henry A. Wallace Beltsville Agricultural Research Center...
http://www.usna.usda.gov/index.htm, Washington, D.C.Washington, D.C.Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
, USA. Acc. nos. 76225, 76226, 76243, 76248.