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Ulmus wallichianaPlanch., the Himalayan elm, also known as the Kashmir elm and Bhutan elm, is a mountain tree ranging from central Nuristan in Afghanistan, through northern Pakistan and northern India to western Nepal at elevations of 800–3000 m. Although dissimilar in appearance, its common name is occasionally used in error for the cherry bark elm Ulmus villosa, which is also endemic to the Kashmir, but inhabits the valleys, not the mountain slopes. The species is closely related to the wych elm U. glabra.
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 'Nanguen' is a complex fourth generation Dutch hybrid cultivar raised at the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen. Lutèce was derived from the cross 'Plantyn' ×, an ancestry comprising four field elms, a wych elm, the curious Exeter Elm ('Exoniensis'), and a frost-resistant selection of the Himalayan elm.
Ulmus 'New Horizon' is an American hybrid cultivar raised by the Wisconsin Alumni Research Foundation (WARF), from a crossing of the Japanese Elm clone W43-8 = 'Reseda' with Siberian Elm clone W426 grown from seed collected from a street tree at Yankton, South Dakota. Tested in the US National Elm Trial coordinated by Colorado State University, 'New Horizon' averaged a survival rate of 74% after 10 years.'New Horizon' was patented in the US in 1994, while in Europe, it is marketed as one of the 'Resista' elms protected under EU breeders' rights.
Ulmus 'Clusius' is a Dutch hybrid elm cultivar raised at the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen, and released to commerce in 1983. 'Clusius' was derived from a crossing of the same Dutch clones that produced the fastigiate 'Lobel' released in 1973: '202' and '336'.
Ulmus × hollandica 'Commelin' is a Dutch hybrid cultivar released for sale in 1960. The tree was raised at Baarn as clone 274 by the Foundation Willie Commelin Scholten Phytopathological Laboratory in 1940, from a crossing of Ulmus × hollandica 'Vegeta' and clone 1, an Ulmus minor selected from a 1929 elm seedlings lot obtained from the Barbier nursery, Orléans.
The Dutch hybrid cultivar Ulmus 'Dodoens' was derived from a selfed seedling of a crossing of the Exeter Elm Ulmus 'Exoniensis' with the Himalayan Elm Ulmus wallichiana at the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen. The tree was one of several cultivars prepared for release in 1970, but delayed by the outbreak of the second, far more aggressive strain of Dutch elm disease.
The Dutch hybrid elm cultivar Ulmus × hollandica 'Groeneveld' was cloned in 1949 at the De Dorschkamp Institute, Wageningen, and released in 1963 in response to the earlier, less virulent form of Dutch elm disease that afflicted Europe shortly after the First World War. The cultivar was derived from a crossing of Dutch clones '49', and '1', a Field Elm Ulmus minor found in central France and marketed by the Barbier nursery in Orléans.
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 'Lobel' is a Dutch hybrid cultivar raised at the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen, from a crossing of clone '202' with '336'. 'Lobel' was cloned in 1962 and released for sale in 1973.
The hybrid elm cultivar Ulmus × hollandica 'Pioneer' is an American clone arising from the crossing of two European species, Wych Elm U. glabra and Field Elm U. minor. Raised by the USDA station at Delaware, Ohio, in 1971, 'Pioneer' was released to commerce in 1983.
Ulmus 'Plantyn' was one of three Dutch hybrid elms released by the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen, in 1973. Derived from a crossing of the Dutch hybrids '202' and '302', it was to prove of great significance in later developments. A selfed seedling was to become the first Dutch clone to prove effectively immune to disease, released in 1989 as 'Columella'. 'Plantyn' was also destined to be the female parent of Lutèce released in 2002. In Italy, 'Plantyn' was used again as female parent in hybridizations with the Siberian Elm Ulmus pumila by the Istituto per la Protezione delle Piante (IPP), to create three new cultivars better adapted to the Mediterranean climate.
Ulmus 'Regal' is an American hybrid elm cultivar developed by the University of Wisconsin–Madison and released in 1983. 'Regal' was derived from seeds arising from the crossing of the Dutch hybrid clones 'Commelin' and '215' sent in 1960 by Hans M. Heybroek of the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen, Netherlands.
The hybrid elm cultivar Ulmus × hollandica 'Belgica', one of a number of hybrids arising from the crossing of Wych Elm with a variety of Field Elm, was reputedly raised in the nurseries of the Abbey of the Dunes, Veurne, in 1694. Popular throughout Belgium and the Netherlands in the 19th century both as an ornamental and as a shelter-belt tree, it was the 'Hollandse iep' in these countries, as distinct from the tree known as 'Dutch Elm' in Great Britain and Ireland since the 17th century: Ulmus × hollandica 'Major'. In Francophone Belgium it was known as orme gras de Malines.
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 'Columella' is a Dutch elm cultivar raised by the Dorschkamp Research Institute for Forestry & Landscape Planning, Wageningen, from a selfed or openly pollinated seedling of the hybrid clone 'Plantyn' sown in 1967. It was released for sale in 1989 after proving extremely resistant to Dutch elm disease following inoculation with unnaturally high doses of the pathogen, Ophiostoma novo-ulmi. However, propagated by grafting onto wych elm rootstocks, graft failure owing to incompatibility has become a common occurrence in the Netherlands.
The Field Elm cultivar Ulmus minor 'Christine Buisman' was the first cultivar released by the Dutch elm breeding programme, initiated in response to the less virulent form of Dutch elm disease (DED), Ophiostoma ulmi, which afflicted Europe's elms after the First World War. 'Christine Buisman' was selected from a batch of 390 seedlings grown from seed collected in the Parque de la Quinta de la Fuente del Berro, Madrid, by Mrs Van Eeghen, a friend of elm researcher Johanna Westerdijk, in 1929 and named for the elm disease researcher Christine Buisman. Originally identified as Ulmus foliacea, it was later treated as Ulmus × hollandica by Melville. However, more recent research in Belgium using DNA markers has reaffirmed 'Christine Buisman' as a clone of U. minor.
The elm cultivar Ulmus minor 'Bea Schwarz' was cloned at Wageningen in the Netherlands, by the elm disease committee, from a selection of Ulmus minor found in France in 1939. However, specimens of the tree grown in the UK and the United States are falsely treated as Ulmus × hollandica.
The hybrid elm cultivar Ulmus 'Den Haag' is a Dutch development derived from a chance crossing of the Siberian Elm cultivar Ulmus pumila 'Pinnato-ramosa' and the Belgian Elm Ulmus × hollandica 'Belgica'. S. G. A. Doorenbos (1891-1980), Director of Public Parks in The Hague, finding that seeds he had sown in 1936 from the Zuiderpark 'Pinnato-ramosa' had hybridized with the local 'Belgica', selected six for trials. The best was cloned and grafted on 'Belgica' rootstock as 'Den Haag'; it was planted first in that city, then released to nurseries elsewhere in the Netherlands. The other five were also planted in The Hague.
Ulmus 'Rebona' is an American hybrid cultivar raised by the Wisconsin Alumni Research Foundation (WARF) as selection 'W916', derived from a crossing of Japanese Elm clone W43-8 = 'Reseda' with Siberian Elm clone W426 grown from seed collected from a street tree at Yankton, South Dakota. The tree was registered in 1993 by Conrad Appel KG, of Darmstadt and is a sibling of 'New Horizon'. In Europe, 'Rebona' is marketed as a Resista elm protected under E U breeders' rights.
References
- ↑ Heybroek, H. M., Goudzwaard, L, Kaljee, H. (2009). Iep of olm, karakterboom van de Lage Landen (:Elm, a tree with character of the Low Countries). KNNV, Uitgeverij. ISBN 978-90-5011-281-9
- ↑ Heybroek, H.M. (1993). "The Dutch Elm Breeding Program". In Sticklen, Mariam B.; Sherald, James L. (eds.). Dutch Elm Disease Research. New York, USA: Springer-Verlag. pp. 16–25. ISBN 978-1-4615-6874-2 . Retrieved 26 October 2017..