Richens believed that English Elm was a particular clone of the variable species Ulmus minor , referring to it as Ulmus minor var. vulgaris . [8] A 2004 survey of genetic diversity in Spain, Italy and the UK confirmed that English Elms are indeed genetically identical, clones of a single tree, said to be Columella 's 'Atinian Elm', [9] once widely used for training vines , and assumed to have been brought to the British Isles by Romans for that purpose. [10] Thus, despite its name, the origin of the tree is widely believed to be Italy, [9] [11] though the clone is no longer found there and has not yet been identified further east. [12]

Dr Max Coleman of the Royal Botanic Garden, Edinburgh writes (2009): "The advent of DNA fingerprinting has shed considerable light on the question. A number of studies have now shown that the distinctive forms that Melville elevated to species and Richens lumped together as field elm are single clones, all genetically identical, that have been propagated by vegetative means such as cuttings or root suckers. This means that enigmatic British elms such as ... English Elm have turned out to be single clones of field elm." [13] Most floras and field guides, however, do not list English Elm as a form of Ulmus minor , but rather as Ulmus procera .

The tree does not produce fertile seed as it is female-sterile, and natural regeneration is entirely by root suckers . [8] [23] Seed production in England was often unknown in any case. [24] By the late 19th century, urban specimens in Britain were often grafted on to wych elm root-stock to eliminate suckering; Henry noted that this method of propagation seldom produced good specimens. [7]

The British Sylva, and Planters and Foresters Manual.

The British Sylva, and Planters and Foresters Manual.

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