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Ulmus pumila, the Siberian elm, is a tree native to Asia. It is also known as the Asiatic elm and dwarf elm, but sometimes miscalled the 'Chinese elm'. U. pumila has been widely cultivated throughout Asia, North America, Argentina, and southern Europe, becoming naturalized in many places, notably across much of the United States.
Ulmus davidiana var. japonica, the Japanese elm, is one of the larger and more graceful Asiatic elms, endemic to much of continental northeast Asia and Japan, where it grows in swamp forest on young alluvial soils, although much of this habitat has now been lost to intensive rice cultivation.
Ulmus castaneifoliaHemsley, the chestnut-leafed elm or multinerved elm, is a small deciduous tree found across much of China in broadleaved forests at elevations of 500–1,600 metres (1,600–5,200 ft).
Ulmus macrocarpaHance, the large-fruited elm, is a deciduous tree or large shrub endemic to the Far East excluding Japan. It is notable for its tolerance of drought and extreme cold and is the predominant vegetation on the dunes of the Khorchin sandy lands in the Jilin province of north-eastern China, making a small tree at the base of the dunes, and a shrub at the top.
Ulmus 'Homestead' is an American hybrid elm cultivar raised by Alden Townsend of the United States National Arboretum at the Nursery Crops Laboratory in Delaware, Ohio. The cultivar arose from a 1970 crossing of the Siberian Elm Ulmus pumila with the hybrid N 215, the latter grown from seed sent in 1960 to the University of Wisconsin-Madison elm breeding team by Hans Heybroek of the De Dorschkamp Research Institute in the Netherlands. Tested in the US National Elm Trial coordinated by Colorado State University, 'Homestead' averaged a survival rate of 85% after 10 years. 'Homestead' was released to commerce without patent restrictions in 1984.
Ulmus 'Sapporo Autumn Gold' is one of the most commercially successful hybrid elm cultivars ever marketed, widely planted across North America and western Europe, although it has now been largely supplanted by more recent introductions. Arising from a chance crossing of the Japanese elm and Siberian elm, seed was sent in 1958 by Prof. Nobuku Takahashi and his colleagues at the Sapporo Botanical Garden of Hokkaido University, Sapporo, to Eugene Smalley at the University of Wisconsin–Madison. The patent issued in 1975 has expired, and there are now no propagation restrictions. However, the tree has proven weak-wooded on maturity, and its popularity has waned in Europe as a consequence of susceptibility to wind damage.
Ulmus gausseniiW. C. Cheng, the Anhui, or hairy, elm, is a medium size deciduous tree whose natural range is restricted to the valleys of the Langya limestone mountains of Chu Xian in Anhui Province, eastern China. The tree was most commonly found on the flood plains, indicating a tolerance of periodic inundation. However, U. gaussenii is now possibly the rarest and most endangered elm species, with only approximately 30 trees known to survive in the wild in 2009.
Ulmus 'Urban' is an American hybrid elm cultivar selected from the progeny of a controlled crossing of the Siberian Elm Ulmus pumila with the Dutch clone '148' in 1958 by Toru Arisumi of the USDA at Columbus, Ohio. Clone '148' had been sent to the US from the Netherlands in 1952 by Johanna Went, leader of the elm research team at the Willie Commelin Scholten Phytopathology Laboratory in Baarn.
Ulmus 'Morton' is an elm cultivar cloned from a putative intraspecific hybrid planted at the Morton Arboretum in 1924, which itself originated as seed collected from a tree at the Arnold Arboretum in Massachusetts. Although this tree was originally identified as Ulmus crassifolia, it is now believed to have been a hybrid of the Japanese elm and Wilson's elm. Accolade has proven to be the most successful cultivar tested in the US National Elm Trial, averaging a survival rate of 92.5% overall.
Ulmus 'Morton Red Tip' is a hybrid cultivar raised by the Morton Arboretum from an open pollination of Ulmus 'Morton'. The tree has occasionally been reported as a hybrid of Accolade with the Siberian Elm Ulmus pumila, an error probably owing to the commercial propagation of the tree by grafting onto U. pumila rootstocks. Tested in the US National Elm Trial coordinated by Colorado State University, Danada Charm averaged a survival rate of 77.5% after 10 years.
Ulmus 'Cathedral' is a hybrid cultivar raised at University of Wisconsin–Madison patented in 1994. Arising from a chance crossing of the Japanese elm and Siberian elm, seed was sent in 1958 by Prof. Nobuku Takahashi and his colleagues at the Sapporo Botanical Garden of Hokkaido University, Sapporo, to Eugene Smalley at Wisconsin–Madison; 'Cathedral' is thus a sibling of 'Sapporo Autumn Gold'.
The American Elm cultivar Ulmus americana 'Valley Forge' was raised by the Agricultural Research Service in Maryland. The tree was released to wholesale nurseries without patent restrictions by the U. S. National Arboretum in 1995 after proving to have a high resistance to Dutch elm disease. 'Valley Forge' proved only moderately successful in the US National Elm Trial, averaging a survival rate of 66.7% overall, owing largely to environmental factors rather than susceptibility to disease.
The Japanese Elm cultivar Ulmus davidianavar.japonica 'Jacan' is a cold-resistant selection from Canada. The tree was one of a group of second-generation japonica seedlings raised in the 1970s, originally for use in the prairie regions, by the Morden Research Station, Morden, Manitoba. It was first distributed in 1977, and was later among the Asiatic elms, some sourced from Canada, donated to the UK in 1980 by the London branch of Mitsui & Co.
The hybrid elm cultivar Ulmus × intermedia 'Lincoln' was selected from crossings of the Slippery, or Red, Elm Ulmus rubra and the Siberian Elm Ulmus pumila made in Aurora, Illinois, circa 1958 and patented in 1983 by Samuel Clegg of Clegg Landscaping, Plainfield, IL and Charles McFarland of Urbana, IL.
The American elm cultivar Ulmus americana 'Lewis & Clark' is a development from the North Dakota State University (NDSU) Research Foundation breeding programme, released in 2004 to commemorate the 200th anniversary of the eponymous expedition. The cultivar was cloned from a tree discovered in 1994 along the Wild Rice River south west of Fargo, North Dakota, where all those around it had succumbed to Dutch elm disease; the tree remains in perfect health (2008). Prairie Expedition proved only moderately successful in the US National Elm Trial, averaging a survival rate of 62.6% overall, potentially due to environmental factors rather than susceptibility to Dutch elm disease.
The Japanese elm cultivar Ulmus davidianavar.japonica 'Prospector' was originally treated as a cultivar of Wilson's elm U. wilsonianaSchneid., a species sunk as Ulmus davidiana var. japonica by Fu. A U.S. National Arboretum introduction, it was selected in 1975 from a batch of 1965 seedlings in Delaware, Ohio, and released without patent restrictions in 1990. 'Prospector' proved moderately successful in the US National Elm Trial, averaging a survival rate of 76% overall.
Ulmus 'Patriot' is a hybrid cultivar raised by the United States National Arboretum in 1980. Derived from a crossing of the American hybrid 'Urban' with the Wilson's Elm cultivar 'Prospector', 'Patriot' was released to commerce, free of patent restrictions, in 1993. Tested in the US National Elm Trial coordinated by Colorado State University, 'Patriot' averaged a survival rate of 85% after 10 years.
Ulmus 'Recerta' is an American hybrid cultivar raised by the Wisconsin Alumni Research Foundation (WARF) as selection '196-5' from seed obtained from a Siberian Elm Ulmus pumila in Volgograd, Russia; the male parent deduced as the Field Elm Ulmus minor.
Ulmus parvifolia, commonly known as the Chinese elm or lacebark elm, is a species native to eastern Asia, including China, India, Japan, Korea, and Vietnam. It has been described as "one of the most splendid elms, having the poise of a graceful Nothofagus".
The American Elm cultivar Ulmus americana 'St. Croix' is a recent (2008) selection cloned from a large tree growing on a farm near Afton, Minnesota, which has displayed a high resistance to Dutch elm disease (DED). A U S patent, PP 20097, was granted in 2009.
References
- 1 2 3 4 Lindquist, C. H. & Howe, J. A. G. (1979). Thomson Elm. Canadian Journal of Plant Science 59:1159
- ↑ Schroeder, W. (1994). Genetic improvement for prairie tree plantings. Journal of Arboriculture. 20(1), Jan. 1994.
- ↑ Burdekin, D.A.; Rushforth, K.D. (November 1996). "Elms resistant to Dutch elm disease" (PDF). Arboriculture Research Note. 2/96. Revised by J.F. Webber. Alice Holt Lodge, Farnham: Arboricultural Advisory & Information Service: 1–9. ISSN 1362-5128 . Retrieved 26 October 2017.
- ↑ Tree, bark, buds and leaves photographs of 'Thomson', worldplants.ca
- ↑ Heybroek, Hans M. (1981). "The Japanese elm species and their value for the Dutch elm breeding program" (PDF). Proceedings of the Dutch Elm Disease symposium and workshop, October 5–9, Winnipeg, Manitoba: 78–90.