Ulmus × hollandicaMill. is a natural hybrid between Wych ElmUlmus glabra and Field ElmUlmus minor that commonly occurs across Europe wherever the ranges of the two parent species overlap. It has also been widely planted elsewhere by Man [1][2][3]. The trees and leaves are broadly intermediate between the two species, but resistance to Dutch elm disease is often greater than either's [4][5]. Introduced to North America and Australasia, many old trees still survive in New Zealand, notably in Auckland, the finest considered to be the specimen found outside the Ellerslie Racecourse[6].
^ Bean, W. J. (1981). Trees and shrubs hardy in Great Britain, 7th edition. Murray, London.
^ Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp 1848-1929. Private publication, Edinburgh.
^ Richens, R. H. (1983). Elm. Cambridge University Press.
^ Burdekin, D. A. & Rushforth, K. D. (Revised by Webber J. F. 1996). Elms resistant to Dutch elm disease. Arboricultural Research Note 2/96. Arboricultural Advisory and Information Service, Alice Holt, Farnham, UK.
^ Collin, E. (2001). Elm. In Teissier du Cros (Ed.) (2001) Forest Genetic Resources Management and Conservation. France as a case study. Ministry of Agriculture and Fisheries, Bureau of Genetic Resources. INRA DIC. France.
^ Auckland Botanical Society (2003). Journal Vol. 58 (1), June 2003. ISSN 0113-41332