Elms
Elms occur throughout the temperate regions of the northern hemisphere. Typically the leaves
are asymmetrical with a double-toothed leaf margin, features unique to this group of trees. Elm
flowers are rather inconspicuous, with both male and female parts, and are wind pollinated. In
Britain this takes place early in the year before the leaves emerge. E. E. Turner in the Essex
Naturalist of 1911 gives a table of the first flowering dates of the 'Common Elm' (possibly
including more than one species) at Coggeshall. He noted a great variation in the dates
recorded:-
1884 Feb. 18
1885 Feb. 23
1886 Mar. 27
1887 Mar. 6
1888 Mar. 14
1889 Mar. 29
1890 Jan. 31
1891 Mar. 15
1892 Feb. 5
1893 Feb. 19
1894 Feb. 10
1895 Mar. 24
1896 Feb. 23
1897 Feb. 27
1898 Feb. 6
1899 Feb. 19
1900 Feb. 25
1901 Feb. 24
1902 Mar. 9
1903 Feb. 7
1904 Mar. 20
1905 Jan
1906 Mar. 3
1907 Mar. 3
1909 Mar. 28
1910 Feb. 19
1911 Feb. 11
Of the elms in Britain only Wych Elm regularly sets viable seed; the other elms do not, a
fact which has often been used to support the theory that these elms are not native. Elms will
readily hybridise giving rise to new, and fertile, elms (Richens, 1983). Elm fruit, a conspicu-
ously winged samara, does not remain viable for long under natural conditions (Fig. 1).
In ordinary years elms produce little or no viable seed. However, relatively infrequently
they have years in which an abundance of seed is produced. 1942 and 1909 are two such years
Fig. 1 Elm Samarae - from left to right - East Anglian Elm,
Wych Elm and English Elm, all approximately x 1
this century (Richens, 1983). Miller Christy (1909) reported in the Essex Naturalist of that year
on the abundant seed, referring to it as the most striking botanical feature of the year'. A
prodigious quantity of seed had set upon the elms, especially those in north Essex, presumably
Hybrid and East Anglian Elms. At the same time the trees produced little or no foliage. It was
not until later in the year that leaf appeared and was sparser than usual. Copious fruiting uses
up the short-shoots on a branch and results in less leafage than usual.
At the end of May and beginning of June the samarae, blown from the trees, drifted into
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