Ulmus macrocarpa - Large-fruited Elm
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| Ulmus macrocarpa Hance |
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The Large-fruited Elm Ulmus macrocarpa Hance is a small 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 Korqin 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 [3]. As is obvious from its name, the tree is distinguished by its large, orbicular, wafer-like samarae < 50 mm in diameter. The tree can reach a height of 17 m, with a slender trunk rarely exceeding 0.4 m d.b.h. The bark is longitudinally fissured, and dark grey in colour. The twigs often develop corky wings that may persist for several years. The leaves are usually obovate, up to 9 cm in length, and chiefly characterized by their thick, leathery texture. The wind-pollinated petal-less flowers appear from March until May, and the seeds from April to June. [1] [2]
The species was introduced to the USA at the Arnold Arboretum, Massachusetts, in 1908, and to the UK at Aldenham House in Hertfordshire, almost certainly as part of the quincunx elm avenue leading to the front of the house [3], by Vicary Gibbs (1853-1932) in the late 19th century[4]. What remained of the avenue after the advent of Dutch elm disease was cleared circa 1980 to make way for a cricket pitch.
Possessed of a moderate resistance to Dutch elm disease, and a low susceptibility to elm yellows, the tree has been assessed at the Morton Arboretum, Illinois, for its landscape potential, and is now considered suitable for open areas such as parks and campuses [5]. It has also proven very resistant to the Elm Leaf Beetle Xanthogaleruca luteola in trials in Oklahoma [4]. However, it is intolerant of poorly-drained ground prone to waterlogging. U. macrocarpa has been found to be the most cold hardy of the Chinese elms. In artificial freezing tests at the Morton Arboretum [6] the LT50 (temp. at which 50% of tissues die) was - 36 °C.
By the age of ten years, the tree bears a close resemblance to the American Elm U. americana, but will never approach the latter's size. There are no known cultivars of this taxon.
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[edit] Subspecies & varieties
Two varieties are recognized: var. glabra Nie & Huang and var. macrocarpa L.K.Fu
[edit] Hybrid cultivars
U. macrocarpa is believed to have been used in recent (post 2000) hybridization experiments at the Morton Arboretum [7] but results have yet (2008) to be published.
[edit] Arboreta etc accessions
- North America
- Arnold Arboretum, acc. nos. 17911, 346-82 (no provenances for either), 377-40 collected in China.
- Denver Botanic Gardens, one specimen, no details available
- Holden Arboretum, U. macrocarpa var. dorsetti (unrecognized name), acc. no. 97-26.
- Morton Arboretum, acc. nos. 589-64, 179-84, 286-95.
- Europe
- Botanic Garden of the University of Copenhagen, no details available
- Brighton & Hove City Council, NCCPG elm collection [5].
- Cambridge Botanic Garden [6], University of Cambridge, UK, no accession details available.
- Great Fontley Farm, Fareham, UK, Butterfly Conservation Elm Trials plantation, Home Field K2, K8, (from seed donated by the Beijing Botanic Garden).
- Royal Botanic Garden Edinburgh, acc. no. 20022149 (grown from seed supplied by Lawyer Nusrery, USA).
- Strona Arboretum [7], University of Life Sciences, Warsaw, Poland. No details available.
[edit] Nurseries
- North America
- Europe
- H. Kolster [9], Boskoop, Netherlands.
[edit] References
- ^ Fu, L. & Jin J. (eds). (1992). China Red Data Book. Rare and endangered plants. Vol. 1. Science Press, Beijing
- ^ Fu, L., Xin, Y. & Whittemore, A. (2002). Ulmaceae, in Wu, Z. & Raven, P. (eds) Flora of China, Vol. 5 (Ulmaceae through Basellaceae). Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis, USA. [1]
- ^ Audrey Le Lievre (1986). An Account of the Garden at Aldenham House and of Its Makers: Henry Hucks Gibbs, Vicary Gibbs and Edwin Beckett. Garden History, Vol. 14, No. 2. (Autumn, 1986), pp. 173-193.
- ^ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London
- ^ Ware, G. (1995). Little-known elms from China: landscape tree possibilities. Journal of Arboriculture, (Nov. 1995). International Society of Arboriculture, Champaign, Illinois, USA. [2]
- ^ Shirazi, A. M. & Ware, G. H. (2004). Evaluation of New Elms from China for Cold Hardiness in Northern Latitudes. International Symposium on Asian Plant Diversity & Systematics 2004, Sakura, Japan.
- ^ Mittempergher, L. & Santini, A. (2004). Elm breeding history. Invest Agrar: Sist Recur For, (2004), 13 (1), 161-177.
