Ulmus aff. 'Plotii', or 'pseudo-Plotii', was the name first used by Melville in the 1940s for elms in England, of various genotypes, that resemble but do not completely match the 'type'-tree, U. minor 'Plotii'.[1] It was taken up again following Dr Max Coleman's findings about Plot Elm (2000)[2] and his paper on British elms (2002).[3]
Melville's brief description, at the end of a paragraph on Plot Elm in a 1948 paper, of "a second small-leaved elm, as yet unnamed, found in the lower Thames Valley and East Anglia", that "shares some of the curious features of the Plot Elm but lacks its graceful habit",[4] may be a reference to his aff. 'Plotii'.
Plot-like field elms have also been observed in U. minor fringe areas outside England.[5] [6]
Elms of the aff. 'Plotii' group "are very close to Plot Elm and have a number of characteristics of the 'type', but their crowns are too broad and regular to match 'true Plot'."[7] They are characterised by some or all of the following diagnostic features: a mature crown of unilateral habit; short shoots that produce more than five leaves in a flush; subequal cordate leaf base; and red club-shaped glandular hairs on leaf surface.
The trees are susceptible to Dutch elm disease, but as they produce abundant root-suckers immature specimens probably survive in their areas of origin.
A few Plot-like field elms have entered cultivation (see Accessions below).
Two trees formerly labelled U. minor subsp. minor × U. minor var. lockii, and referred to in Coleman (2000) as 'pseudo-Plotii',[2] that stand (2016) in the Royal Botanic Garden, Edinburgh, have been re-classified on the RBGE database as U. minor 'Umbraculifera Gracilis'.[8] An elm cultivar of the same clone and similar age, also formerly known as U. aff. 'Plotii',[7] stands on Whitehouse Loan, Bruntsfield Links, Edinburgh.[9]
This group of elms is likely to hybridize in the wild both with wych elm and with U. minor.
