Ulmus minor 'Plotii'

Ulmus minor

'Plotii', near Fineshade, 1911
Cultivar 'Plotii'
Origin England

The Field Elm cultivar Ulmus minor 'Plotii', commonly known as Lock Elm[1][2] or Lock's Elm (its vernacular names), Plot's Elm or Plot Elm, is endemic mainly to the East Midlands of England, notably around the River Witham in Lincolnshire and in the Trent Valley around Newark on Trent[3] and in the village of Laxton, Northamptonshire. It has been described as Britain's rarest native elm, and recorded by The Wildlife Trust as a nationally scarce species.[4]

As with other members of the Field Elm group, the taxonomy of Plot Elm has been a matter of contention, several authorities[5][6][7] recognizing it as a species in its own right. Indeed, it is as U. plotii that the specimens held by the Royal Botanic Gardens at Kew and Wakehurst Place are listed. Richens, however, contended (1983) that it is simply one of the more distinctive clones of the polymorphous Ulmus minor, conjecturing that it arose as an U. minor sport and that its incidence in the English Midlands may have been linked to its use as a distinctive marker along Drovers' roads,[8][9] whereas Melville suggested the tree's distribution may be related to (river) valley systems.[3] After Richens had challenged the species hypothesis, the tree was the subject of a study at the Royal Botanic Garden Edinburgh by Dr Max Coleman (2000), which showed that trees a perfect fit with the 'type' material of Plot elm were of a single clone (genetically identical to each other).[10] Arguing in a 2002 paper that there was no clear distinction between species and subspecies, and suggesting that known or suspected clones of U. minor, once cultivated and named, should be treated as cultivars, Coleman preferred the designation U. minor 'Plotii'.[11]

Henry miscalled the tree Goodyer's Elm, (U. minor 'Goodyeri'). The trees Goodyer discovered were near the south coast at Pennington, Hampshire, some 200 miles away from centre of distribution of 'Plotii' and very dissimilar in structure.[12][13][14]

Description

Before the advent of Dutch elm disease, this slender monopodial tree grew to a height of 30 m and was chiefly characterized by its cocked crown comprising a few short ascending branches; Richens[15] likened its appearance to an ostrich feather.[16] A single longish lower branch appears often to have been a feature of its profile.[17] The obovate to elliptic acuminate leaves are small, rarely > 4 cm in length, with comparatively few marginal teeth, usually < 70; the upper surfaces dull, with a scattering of minute tubercles and hairs.[18][19] The samarae rarely ripen, but when mature are narrowly obovate, < 13 mm in length, with a triangular open notch.[12][13]

Pests and diseases

'Plotii' is very susceptible to Dutch elm disease.

Etymology

The tree was first classified by the Oxford botanist George Claridge Druce in 1907-11,[20][21][22][23] who found examples at Banbury and Fineshade, Northamptonshire and published descriptions with photographs.[24][25][26] Druce named the tree for Dr Robert Plot, a 17th-century English naturalist. The older vernacular name 'Lock Elm' is said to be an allusion to the difficulty in working its timber.[27] However Druce wrote in 1913 that 'The wood is of very good quality, easy to work, and of a different texture from the Wych, Dutch, or English Elm, and has a general usefulness as a substitute for Ash or Wych Elm. The name Lock Elm can have no reference to any difficulty in working or dressing of the wood.'[28] 'Lock' may be related to its use in boundaries, as 'loc' is Old English for enclosure.[29] Lock elm may have been one of the plants used in witchcraft to open locks and reveal hidden treasure.[30] Richens, who had encountered the vernacular name 'Lock's Elm', called the tree U. minor. var. lockii.[31] Bancroft referred to Plot's Elm as the 'East Anglian Elm', adding that it was often referred to as Wych Elm in the region;[32] however, she was almost certainly alluding to the Smooth-leaved Elm.

Cultivation

Ulmus minor 'Plotii' locations in east Midlands, England, after Coleman (2000)[10]
  • 1. Derbyshire
  • 2. Derby U.A.
  • 3. Nottinghamshire
  • 4. Nottingham U.A.
  • 5. Lincolnshire
  • 6. Leicestershire
  • 7. Leicester U.A.
  • 8. Rutland U.A.
  • 9. Northamptonshire

As the two late-19th century specimens at Westonbirt Arboretum[33] showed (mature by 1912 when Augustine Henry photographed one of them for his Trees of Great Britain & Ireland) and the tree at Eastington Park[34][35] (mature by 1946), Plot-type elms had been noted as distinctive and were being included in collections before they were classified botanically by George Claridge Druce (1911). Melville confirmed by field studies in the 1930s that Druce's specimens[36] were typical ('the type'),[3] but believing plotii to be a species and so to some extent variable he also admitted to Kew 'Plot Elms' that varied from the type.[37] Cultivation in the decades that followed, influenced by Melville or sourced from Kew, allowed similar latitude. Following Coleman's findings about the type (2000) and his paper on British elms (2002), atypical Plot's Elms or 'Plot-type' elms are classified as Ulmus aff. 'Plotii'. These are very close to Plot's Elm and have a number of characteristics of the type, but their crowns are too broad and regular to match "true Plot".[10][11] It is now thought likely that the Westonbirt specimens were elms of the 'Plot-type' category.[38]

An uncommon tree even before Dutch elm disease, 'Plotii' has also been affected by the destruction of hedgerows and by urban development within its limited range.[4][39] No mature 'type' trees are known to survive. The last known stand of semi-mature Plot or Plot-type elms, the Madingley Road elms descended from those described by Elwes and Henry in 1913[40] and by Richens in 1960,[41] was destroyed by the City Council of Richens's own Cambridge in road-widening c.2007-2014.[42] Unlike other forms of the Field Elm, 'Plotii' is not a prolific generator of suckers,[43] but it is not considered critically endangered. Conservation measures were drafted to preserve known stands and to encourage propagation,[4] though it is not clear if any of these were implemented.

"The Plot Elm is a beautiful tree," wrote Gerald Wilkinson, with "a silhouette no broader than Wheatley's." Wilkinson regarded as a "lost opportunity" the failure of East Midlands councils to cultivate this local elm in preference to exotic plantsmen's varieties. "Unhappily, the plumes of U. plotii are no longer a common feature of the landscape of the Trent above Newark and the Witham above Lincoln. Elms are now [1978] few in these areas that were once the home of Plot Elm. A wartime shortage of wood, altered drainage levels, land clearance for power stations, and machine farming have all combined into the familiar pattern of short-term efficiency and long-term degradation."[44]

Outside botanical collections the 'type' tree was seldom planted as an ornamental,[45] and it is no longer planted owing to its susceptibility to Dutch elm disease. It appears in National Elm Collection lists,[46] but no specimen is known in the Brighton area (2015). The tree is not known in continental Europe, save three small (2014) specimens grown in a private garden at Seyne les Alpes, France.

Natural hybrids

Plot Elm hybridizes in the wild both with wych elm,[3][47] to form U. × hollandica 'Elegantissima', and with U. minor to form Ulmus × viminalis. Melville noted that within the limits of the tree's distribution, hybrids are more common than Plot's Elm itself.[3]

Hybrid cultivars

Elms of the Ulmus × viminalis group have been cultivated since the 19th century and have given rise to a hybrid cultivar of that name and to the cultivars 'Aurea', 'Marginata', 'Pulverulenta'.[48] The 19th-century cultivar 'Myrtifolia' was considered by Melville to be a probable U. minor × U. minor 'Plotii' hybrid.[49] The cultivar Wentworth Elm was identified by the Royal Botanic Garden Edinburgh as a hybrid of Huntingdon Elm and Plot Elm, though Melville dismissed the specimen growing at the Royal Botanic Gardens, Kew as Huntingdon Elm.[50] The 20th-century dwarf elm cultivar 'Jacqueline Hillier' is thought to belong to the 'Elegantissima' group.[51]

Notable trees

A mature avenue of the 'type' tree stood at Newton on Trent, Lincolnshire, in the early 20th century[52] and a notable quantity grew by the river Tove at Towcester and was present until at least 1955.[53]

The largest known assemblage of Plot elm survives (2015) as a hedge of young trees near Caythorpe, Nottinghamshire.

The Plot Elm in art

George Lambert's landscape 'View of Dunton Hall, Lincolnshire', painted in 1739 near Tydd St Mary within the native range of Plot Elm, shows a narrow monopodial elm-like tree with short branches and cocked crown, that may be a rare representation of Plot Elm in art. Tydd St Mary is not far from the River Welland, where Melville had noted the presence of Plot Elm.[3]

Accessions

North America
Europe

References

  1. ↑ Wright, Joseph. The English dialect dictionary 3. 1905. p. 637.
  2. ↑ Gould, S.C. & L.M. (1901). Notes and Queries 7. pp. 229, 353, 453.
  3. 1 2 3 4 5 6 Melville, Ronald, The Journal of Botany, London, Vol.78, Aug. 1940
  4. 1 2 3 Plot’s Elm (Ulmus Plotii). Wildlifebcnp.org. Retrieved on 2012-03-22.
  5. ↑ Armstrong, J. V. & Sell, P. D. (1996). "A revision of the British elms (Ulmus L., Ulmaceae): the historical background". Botanical Journal of the Linnean Society 120: 39–50. doi:10.1111/j.1095-8339.1996.tb00478.x.
  6. ↑ Stace, C. A. (1997). New Flora of the British Isles, 2nd edition. Cambridge University Press.
  7. ↑ Melville, R. (1978). "On the discrimination of species in hybrid swarms with special reference to Ulmus and the nomenclature of U. minor (Mill.) and U. carpinifolia (Gled.)". Taxon 27 (4): 345–351. doi:10.2307/1220370. JSTOR 1220370.
  8. ↑ Richens, R. H., Elm, Cambridge 1983, p.54
  9. ↑ Max Coleman, ed.: Wych Elm (Royal Botanic Garden Edinburgh publication, 2009; ISBN 978-1-906129-21-7); p. 22
  10. 1 2 3 Coleman, M., Hollingsworth, M. L. and Hollingsworth, P. M. (2000). "Application of RAPDs to the critical taxonomy of the English endemic elm Ulmus plotii Druce". Botanical Journal of the Linnean Society 133 (3): 241–262. doi:10.1111/j.1095-8339.2000.tb01545.x.
  11. 1 2 Coleman M. (2002) 'British elms.' British Wildlife 13 (6): 390-395.
  12. 1 2 Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp. 1848–1929. Private publication.
  13. 1 2 White, J. & More, D. (2002). Trees of Britain & Northern Europe. Cassell's, London.
  14. ↑ Chatters, C. (2009) Flowers of the Forest – Plants and people of the New Forest National Park. Wildguides, Old Basing, England. ISBN 978-1-903657-19-5
  15. ↑ Richens, R. H. (1968). The correct designation of the European field elms. Feddes Repertorium 79: 1 –2.
  16. ↑ Photograph of young U. minor var. plotii in R. H. Richens, Elm (Cambridge 1983), p. 4
  17. ↑ See Wilkinson's photo 'Plot Elms finely grown' & 'Young Plot in Trent Valley' (plot-elms.co.uk/home/unknown-location-plot-elms), Druce's Banbury photo (plot-elms.co.uk/home/oxfordshire-plot-elms), Stace's Lowesby photo 3 (plot-elms.co.uk/home/leicestershire-plot-elms), Westonbirt photo, Bruntsfield Links elm, etc.
  18. ↑ Photograph 1 of Plot's Elm leaves, elmer.rbge.org.uk
  19. ↑ Photograph 2 of Plot's Elm leaves, elmer.rbge.org.uk
  20. ↑ Botanical Exchange Club of the British Isles, report for 1907 (Oxford, 1908), p.258 archive.bsbi.org.uk/BEC_1907.pdf
  21. ↑ Journal of the Northamptonshire Natural History Society, Vol. 16, December 1911
  22. ↑ Gard. Chron. vol. 50 (1911 July–Dec.), p. 408, and vol. 51 (1912 Jan– June), p. 35.
  23. ↑ Druce, George Claridge (1908). List of British plants. Oxford: Clarendon press. p. 63.
  24. ↑ Gardeners' Chronicle photograph of Ulmus Plotii Druce near Fineshade, Northamptonshire, 'Plot Elms', www.plot-elms.co.uk
  25. ↑ Melville, Ronald, Journal of Botany (London, Aug. 1940)
  26. ↑ Wilkinson, Gerald, Epitaph for the Elm (London, 1978)
  27. ↑ Gurney, R. (1958). Trees of Britain. Faber & Faber, London.
  28. ↑ The Botanical Exchange Club and Society Of The British Isles, Vol III, Part 5. page 400
  29. ↑ http://hord.ca/projects/eow/result.php?nt=loc&submit=+Search+&l=Both&ignorecase=on&match=word&output=macron
  30. ↑ Thiselton Dyer, T. F. (1889). The Folk-lore of Plants. pp. 51, 82, 196, 197.
  31. ↑ Richens, R. H., Elm, Cambridge 1983, p.4
  32. ↑ Bancroft, H. (1934). Notes on the Status and Nomenclature of the British Elms. Gardeners' Chronicle XCVI.
  33. ↑ Jackson, A. Bruce, Catalogue of the Trees & Shrubs [at Westonbirt] in the Collection of the Late Lieut-Col. Sir George Lindsay Holford (London 1927), p.195; contains a second photograph.
  34. ↑ Riddelsdell, H J; Hedley, G W; Price, W R (1948). Flora of Gloucestershire. Cheltenham: Cotteswold Naturalists' Field Club. p. 432.
  35. ↑ "Gloucestershire Plot Elms". Plot Elms.
  36. ↑ Ulmus Plotii Druce near Fineshade, Northamptonshire, Gardeners' Chronicle, www.plot-elms.co.uk
  37. ↑ Wilkinson, Gerald, Epitaph for the Elm (London, 1978), p.74
  38. ↑ Coleman, Max, private communication (Aug. 2015)
  39. ↑ Wilkinson, Gerald, Epitaph for the Elm, London 1978, pp.72–74
  40. ↑ Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp. 1848–1929. Private publication.
  41. ↑ Nature in Cambridgeshire, vol 3, 1960
  42. ↑ Plot Elms on Madingley Road, Cambridge, 2006, sabre-roads.org.uk and 2013, geograph.org.uk
  43. ↑ Messenger, Guy, BSBI News 55, 8–9
  44. ↑ Wilkinson, Gerald, Epitaph for the Elm, London 1978, p.74
  45. ↑ Coleman, Max, private communication, Nov. 2013.
  46. ↑ http: brighton-hove.gov.uk/content/leisure-and-libraries/parks-and-green-spaces/national-elm-collection
  47. ↑ Richens, R. H., Elm, Cambridge 1983
  48. ↑ Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London, p.659
  49. ↑ Green, P. S. (1964). Registration of cultivar names in Ulmus. Arnoldia, Vol. 24. Arnold Arboretum, Harvard University.
  50. ↑ Green, P. S. (1964). Registration of cultivar names in Ulmus. Arnoldia, Vol. 24. Arnold Arboretum, Harvard University
  51. ↑ Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London, p.653
  52. ↑ Plot Elm avenue, Newton on Trent
  53. ↑ "Northamptonshire Plot elms - Towcester". 2015-12-08.

External links

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