Ulmus × hollandica

Ulmus × hollandica Mill. , often known simply as Dutch elm, is a natural hybrid between wych elm (U. glabra) and field elm (U. minor) which commonly occurs across Europe wherever the ranges of the parent species overlap. In England, according to the field-studies of R. H. Richens, "The largest area [of hybridization] is a band extending across Essex from the Hertfordshire border to southern Suffolk. The next largest is in northern Bedfordshire and adjoining parts of Northamptonshire. Comparable zones occur in Picardy and Cotentin in northern France". Crosses between U. × hollandica and either of the parent species are also classified as U. × hollandica. The botanical name hollandica was first used for an elm variety by Plukenet in 1697 in describing a cultivar of this group now called 'Major'....read more on Wikipedia.