Author's Note
In writing about elms for this issue of the Essex Naturalist, I have come up against a perennial
problem concerning this group of trees: that is, how to name a particular elm given the present
very confused and uncertain state of elm taxonomy. The largely recognisable boundaries that
exist between other tree species of the same genus (for example the genus Quercus, the Oaks),
do not seem to exist between elms. They are a very complex and highly variable group,
seemingly going through a very active evolutionary phase, and apart from Wych Elm and
English Elm, the elms probably form a continuum; the boundaries that taxonomists have
attempted to create between the other elm 'species' in reality may not exist.
So many authors have added to existing, usually unsatisfactory, systems of naming elms that
it is impossible for amateurs to interpret and use them; even specialists seem to confuse different
elms or plainly disagree about what constitutes a particular elm.
I have, therefore, in this book adopted a system used elsewhere (Rackham, 1986) for giving
a name to a particular species of elm or to an apparently related group of elms. I have included
leaf silhouettes of these elms and also where I have done field-work I have added a six-figure
grid reference, in order that the source material can be examined.
It must be remembered that my interpretation of what I see in the field with regard to elms
is not necessarily that of another individual studying elms.
Opinions expressed in this booklet, particularly in relation to previous authors' interpretation
of the Essex elm flora, are my own. They are not necessarily shared by the Council of the Essex
Field Club.
M. W. Hanson, February 1990
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