The field elm (Ulmus minor) cultivar 'Atinia' , commonly known as the English elm, formerly common elm and horse may, and more lately the Atinian elm was, before the spread of Dutch elm disease, the most common field elm in central southern England, though not native there, and one of the largest and fastest-growing deciduous trees in Europe. R. H. Richens noted that elm populations exist in north-west Spain and northern Portugal, and on the Mediterranean coast of France that "closely resemble the English elm" and appear to be "trees of long standing" in those regions rather than recent introductions. Augustine Henry had earlier noted that the supposed English elms planted extensively in the Royal Park at Aranjuez from the late 16th century onwards, specimens said to have been introduced from England by Philip II and "differing in no respects from the English elm in England", behaved as native trees in Spain. He suggested that the tree "may be a true native of Spain, indigenous in the alluvial plains of the great rivers, now almost completely deforested".

Richens believed that English elm was a particular clone of the variable species Ulmus minor, referring to it as Ulmus minor var. vulgaris. 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', once widely used for training vines, and assumed to have been brought to the British Isles by Romans for that purpose. Thus, despite its name, the origin of the tree is widely believed to be Atina, Lazio, in Italy, the home town of Columella, whence he imported it to his vineyards in Cadiz, although the clone is no longer found in Atina and has not yet been identified further east.

Max Coleman of the Royal Botanic Garden, Edinburgh writes: "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, as the flowers are completely sterile. This means that enigmatic British elms such as ... English elm have turned out to be single clones of field elm." Most flora and field guides, however, do not list English elm as a form of U. minor, but rather as U. procera.