A tree to about 90 ft high; leader arching on younger trees; branches few, short, spreading; branchlets pendulous. Leaves elliptic, acute, up to 23⁄4 in. long and 11⁄2 in. wide, obliquely truncate to slightly cordate at the base, dull dark green and almost glabrous above, lower surface glandular at first, glabrous except for axillary tufts, bluntly toothed; lateral veins in seven to ten pairs. Proliferating short shoots (of indefinite growth) are frequent in this species, and have smaller, rounder leaves. Samaras elliptic, about 1⁄2 in. long, bearing the seed in the upper part.
U. plotii was first distinguished as a species by Druce in 1911. He did not study it in any detail, and the first full account of it was published by Dr Melville some thirty years later (Journ. Bot. (Lond.), Vol. 78 (1940), pp. 181-92 and figs. 1-3). According to him, the main area of U. plotii is in the lower valley of the Trent around Newark-on-Trent in Nottinghamshire, below 400 ft, and on the other side of the border with Lincolnshire in the Witham valley. There are more scattered occurrences farther west, as far as Monmouthshire and Shropshire.
Druce believed that this elm was one described by Plot in his Natural History of Oxfordshire (1677). It is now generally accepted that this identification was incorrect – an error that makes ‘Plot’s elm’ an inappropriate vernacular name for this species, though it does not affect the validity of its botanical name. Dr Melville suggested that it should be called Plot elm.
Elwes and Henry identified U. plotii with Miller’s obscure U. minor and also confused it with Goodyer’s elm, for which see U. angustifolia.
U. × diversifolia Melville U. minor Mill. sens. some authors – A tree up to about 65 ft in height with spreading branches and slender wiry branchlets. First-year branchlets 1⁄24 to 1⁄12 in diameter, hairy at first becoming nearly glabrous by the autumn. Spur shoots of three kinds, the majority having leaves with unequal bases, a lesser number with bases equal or nearly so, and a few with both types of leaf together. Leaves with unequal bases, elliptical to obovate acute, veins eight to eleven pairs. Leaves with equal bases, elliptical acute, veins five to nine pairs. Blade of leaf 2 to 31⁄3 in. long, slightly rough above, downy below, margin doubly-serrate. Stalk 3⁄16 to 3⁄8 in. long, downy above. Sucker shoots hairy, with leaves 2⁄5 to 23⁄4 in. long. Flowers ten to twenty-five in a cluster. Samaras 1⁄2 to 3⁄4 in. long, 1⁄3 to 1⁄2 in. broad, ovate to obovate, seed near the notch.
Originally described by Dr Melville as a species, this elm is now considered by him to be a triple hybrid of the parentage U. coritana × U. plotii × U. glabra, the leaves being intermediate between the first two species in shape and texture, but deriving the downiness of the undersides from U. glabra. Its main area is in Hertfordshire, Cambridge and Suffolk. It was originally described in Journ. Bot. (Lond.), Vol. 77 (1939), pp. 138-45; for Dr Melville’s later view see Stace, op. cit., pp. 293-4.
U. × elegantissima Horwood – This was described, as a species, in Flora of Leicestershire and Rutland (1933) and is considered by Dr Melville to be a natural hybrid between U. plotii and the wych elm, U. glabra, occurring fairly frequently from the Trent valley southwards to Hertfordshire and Essex. It is variable, combining in many different ways the characters of the two parents. See further in Stace, op. cit., p. 297.
The elm named ‘Jacqueline Hillier’ is considered to belong to U. × elegantissima. It is shrubby, of dense habit, with small, scabrid leaves, originally found in a garden in the Midlands, and named by Messrs Hillier in 1967.