''Ulmus minor'' 'Plotii'

Ulmus minor cultivar

'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] in the village of Laxton, Northamptonshire. Two further populations existed in Gloucestershire.[4][5] It has been described as Britain's rarest native elm, and recorded by The Wildlife Trust as a nationally scarce species.[6]

As with other members of the Field Elm group, the taxonomy of Plot Elm has been a matter of contention, several authorities[7][8][9] 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. R. H. 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,[10]:54[11] whereas Ronald 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).[12] 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'.[13]

Alfred Rehder considered Ulmus Plotii Druce to be synoymous with Jonathan Stokes' Ulmus surculosa argutifolia which was located at Furnace Mill near North Wingfield, Derbyshire before 1812.[14][15]

Augustine Henry miscalled the tree Goodyer's Elm, (U. minor 'Goodyeri'). The trees John 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.[16][17][18]

Description

Before the advent of Dutch elm disease, this slender monopodial tree grew to a height of 30 metres (98 ft) and was chiefly characterized by its cocked crown comprising a few short ascending branches; Richens[19] likened its appearance to an ostrich feather.[10]:4 A single longish lower branch appears often to have been a feature of its profile.[20] 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.[21] The samarae rarely ripen, but when mature are narrowly obovate, < 13 mm in length, with a triangular open notch.[16][17]

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,[3][22][23][24][25][26] who found examples at Banbury and Fineshade, Northamptonshire and published descriptions with photographs.[3][24][27] 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.[28] 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.'[29] 'Lock' may be related to its use in boundaries, as 'loc' is Old English for enclosure.[30] Lock elm may have been one of the plants used in witchcraft to open locks and reveal hidden treasure.[31] Richens, who had encountered the vernacular name Lock's Elm, called the tree U. minor. var. lockii.[10]:4 A. R. Horwood in his book British Wild Flowers – In Their Natural Haunts, called it the 'Northamptonshire Elm'.[32] Bancroft referred to Plot's Elm as the 'East Anglian Elm', adding that it was often referred to as Wych Elm in the region;[33] however, she was almost certainly alluding to the Smooth-leaved Elm. 'Lock elm' has been in use since at least 1742.[34]

Cultivation

Ulmus minor 'Plotii' locations in east Midlands, England, after Coleman (2000)[12]
  • 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

Plot-type elms had been noted as distinctive and were being cultivated in collections before they were botanically classified by Druce (1911), as evidenced by the two specimens at Westonbirt House[35] (mature by 1912 when Augustine Henry photographed one of them for his Trees of Great Britain & Ireland) and the tree at Eastington Park.[5][36] Melville confirmed by field studies in the 1930s that Druce's specimens[24] 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.[27]:74 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".[12][13]

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.[6][27](pp72–74) No mature 'type' trees are known to survive. One of the last known stands of semi-mature Plot elms, the Madingley Road elms descended from those described by Elwes and Henry in 1913[16] and by Richens in 1960,[37] was destroyed by the City Council of Richens's own Cambridge in road-widening c.2007–2014.[38] Unlike other forms of the Field Elm, 'Plotii' is not a prolific generator of suckers,[4] but it is not considered critically endangered. Conservation measures were drafted to preserve known stands and to encourage propagation,[6] 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."[27]:74

Outside botanical collections, the 'type' tree was seldom planted as an ornamental,[39] and is now only planted occasionally owing to its susceptibility to Dutch elm disease.[40] [41] It appears in National Elm Collection lists,[42] 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][10] 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 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'.[43]:659 The 19th-century cultivar 'Myrtifolia' was considered by Melville to be a probable U. minor × U. minor 'Plotii' hybrid.[44] 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.[44] The 20th-century dwarf elm cultivar 'Jacqueline Hillier' is thought to belong to the 'Elegantissima' group.[43]:653 The cultivar 'Etrusca' was identified by Melville as a hybrid of U. glabra × U. minor 'Plotii'.[44]

Notable trees

The type tree at Banbury was blown down in a gale around 1943; the timber was donated to the Royal Botanic Gardens, Kew.[45] A mature avenue of the 'type' tree stood at Newton on Trent, Lincolnshire, in the early 20th century[46] and a notable quantity grew by the river Tove at Towcester and was present until at least 1955.[47] A large assemblage of Plot elm survives (2015) as a hedge of young trees near Caythorpe, Nottinghamshire. Two large trees survive near Calceby, Lincolnshire (2016).[48]

One of two late 19th-century specimens in the parkland of Westonbirt House, mature by 1912 when Henry photographed it for his Trees of Great Britain & Ireland, was said by Elwes to be the largest-known tree of its kind in Britain.[49] It was 88 feet (27 m) high and 8.1 feet (2.5 m) in girth in 1921.[50] Elwes and Henry examined Druce's 'type' trees in Banbury and the elms of Madingley Road, Cambridge, as well as the Westonbirt specimens, and considered all three the same tree. Some authorities, however, consider the Westonbirt specimens elms of the 'Plot-type' category.[51]

Depiction in art and literature

... Cedric stopped the car when they were well out of the suburbs on the Hertfordshire side, at a place where a by-road ran up a slope of ploughland. At the top was a short row of elms whose crests were asymmetrical – shaped like one-sided foam on a tankard of beer, as if exposed to a prevailing breeze.

– From E. B. C. Jones, Morning and Cloud (1932).[52]

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.[53][54] Tydd St Mary is not far from the River Welland, where Melville had noted the presence of Plot Elm.[3]

A description in E. B. C. Jones's novel Morning and Cloud (1932) of asymmetrical elms in Hertfordshire, where Plot Elm was present,[55][56] may be a rare literary reference to 'Plotii'.

Accessions

North America
Europe

References

  1. ↑ Wright, Joseph (1905). The English dialect dictionary. 3. p. 637.
  2. ↑ Gould, S.C. & L.M. (1901). Notes and Queries. 7. pp. 229, 353, 453.
  3. 1 2 3 4 5 6 7 8 Melville, Ronald (1940). "Contributions to the study of British Elms:- III. The Plot Elm, Ulmus plotii Druce" (PDF). The Journal of Botany. 78: 181–191. Retrieved 13 June 2016.
  4. 1 2 Messenger, Guy (1990). "Plot's elm on the verge of extinction in England?" (PDF). BSBI News. Vol. 55. pp. 8–9. Retrieved 14 June 2016.
  5. 1 2 Riddelsdell, H J; Hedley, G W; Price, W R (1948). Flora of Gloucestershire. Cheltenham: Cotteswold Naturalists' Field Club. p. 432.
  6. 1 2 3 Plot’s Elm (Ulmus Plotii). Wildlifebcnp.org. Retrieved on 2012-03-22.
  7. ↑ 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.
  8. ↑ Stace, C. A. (1997). New Flora of the British Isles, 2nd edition. Cambridge University Press.
  9. ↑ 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. JSTOR 1220370. doi:10.2307/1220370.
  10. 1 2 3 4 Richens, R. H. (1983). Elm. Cambridge University Press. ISBN 0521249163.
  11. ↑ Max Coleman, ed.: Wych Elm (Royal Botanic Garden Edinburgh publication, 2009; ISBN 978-1-906129-21-7); p. 22
  12. 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.
  13. 1 2 Coleman, Max (2002). "British elms". British Wildlife. Vol. 13 no. 6. pp. 390–395.
  14. ↑ Rehder, Alfred (1949). Bibliography of cultivated trees and shrubs hardy in the cooler temperate regions of the Northern Hemisphere. p. 143.
  15. ↑ Stokes, Jonathan (1812). A botanical materia medica. 2. pp. 36–37.
  16. 1 2 3 Elwes, Henry John; Henry, Augustine (1913). The Trees of Great Britain & Ireland. 7. pp. 1901–1902, Plate 403.
  17. 1 2 White, J. & More, D. (2002). Trees of Britain & Northern Europe. Cassell's, London.
  18. ↑ 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
  19. ↑ Richens, R. H. (1968). The correct designation of the European field elms. Feddes Repertorium 79: 1 –2.
  20. ↑ See Wilkinson's photo 'Plot Elms finely grown' & 'Young Plot in Trent Valley', Druce's Banbury photo, Stace's Hungarton photo, Westonbirt photo, Bruntsfield Links elm, etc.
  21. ↑ Herbarium specimens of Ulmus plotii Druce (Banbury), 1911 and of Ulmus minor Mill. 'Plotii' (Banbury), 1946.
  22. ↑ Druce, George Claridge (1908). "Report for 1907" (PDF). Botanical Exchange Club of the British Isles. Oxford: 258. Retrieved 14 June 2016.
  23. ↑ Druce, George Claridge (1911–1912). "Ulmus plotii". Journal of the Northamptonshire Natural History Society. 16: 108. Retrieved 14 June 2016.
  24. 1 2 3 Druce, George Claridge (1911). "New or noteworthy plants". The Gardeners' Chronicle. 3. Vol. 50. pp. 408–409. Retrieved 14 June 2016.
  25. ↑ Druce, George Claridge (1912). "New or noteworthy plants". The Gardeners' Chronicle. 3. Vol. 51. p. 35. Retrieved 14 June 2016.
  26. ↑ Druce, George Claridge (1908). List of British plants. Oxford: Clarendon press. p. 63.
  27. 1 2 3 4 Wilkinson, Gerald (1978). Epitaph for the Elm. London. ISBN 9780091314507.
  28. ↑ Gurney, R. (1958). Trees of Britain. Faber & Faber, London.
  29. ↑ Druce, George Claridge (1914). "Report for 1913" (PDF). Botanical Exchange Club of the British Isles. 5. 3: 399–400. Retrieved 14 June 2016.
  30. ↑ "loc". EOW: Modern - Old English Translator.
  31. ↑ Thiselton Dyer, T. F. (1889). The Folk-lore of Plants. pp. 51, 82, 196, 197.
  32. ↑ Horwood, A. R. (1919). British Wild Flowers - In Their Natural Haunts. 6. The Gresham Publishing Company. p. 208.
  33. ↑ Bancroft, H. (1934). Notes on the Status and Nomenclature of the British Elms. Gardeners' Chronicle XCVI.
  34. ↑ "in Market-Harborough the County of Leicester, late Mr. John Smith, Ironmonger, deceased. ...who hath one hundred Wheel Neaths to sell... made of right Lock Elm". Stamford Mercury. Stamford, Lincolnshire. 18 March 1742. p. 3.
  35. ↑ 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.
  36. ↑ "Gloucestershire Plot Elms". Plot Elms.
  37. ↑ Richens, R. H. (1960). "Cambridgeshire elms" (PDF). Nature in Cambridgeshire. 3: 19. Retrieved 13 June 2016.
  38. ↑ Plot Elms on Madingley Road, Cambridge, 2006, and Madingley Road, Cambridge, 2013
  39. ↑ Coleman, Max, private communication, Nov. 2013.
  40. ↑ Plot elms, historic and current distribution.
  41. ↑ Carr, Johanna (17 May 2012). "Kew's trees planted at Hayle's royal walkway". The West Briton. Archived from the original on July 9, 2013. Retrieved 14 June 2016.
  42. 1 2 "List of plants in the {elm} collection". Brighton & Hove City Council. Retrieved 23 September 2016.
  43. 1 2 Bean, W. J. (1988). Trees and shrubs hardy in Great Britain (8 ed.). London: Murray.
  44. 1 2 3 Green, Peter Shaw (1964). "Registration of cultivar names in Ulmus". Arnoldia. Arnold Arboretum, Harvard University. 24 (6–8): 41–80. Retrieved 16 February 2017.
  45. ↑ "Review of the Work of the Royal Botanic Gardens, Kew, during 1949" (PDF). Kew Bulletin. 5 (1): 11. 1950.
  46. ↑ Plot Elm avenue, Newton on Trent
  47. ↑ "Northamptonshire Plot elms - Towcester". 2015-12-08.
  48. ↑ "Lincolnshire Plot elms - Calceby"
  49. ↑ Elwes, H. J.; Henry, A (1913). The Trees of Great Britain & Ireland. 7.
  50. ↑ Jackson, A. Bruce (1927). Catalogue of the Trees & Shrubs [at Westonbirt] in the Collection of the Late Lieut-Col. Sir George Lindsay Holford. London. p. 195.
  51. ↑ Coleman, Max, private communication (Aug. 2015)
  52. ↑ Jones, E. B. C., Morning and Cloud (1932), p.234
  53. ↑ Photograph of a Hertfordshire Plot Elm for comparison ('The Backs', River Lea, Ware, Herts.) Hammerton, John Alexander (1925). Wonderful Britain. 2. The Fleetway House.
  54. ↑ "Hertfordshire Plot elms - Ware". 2016-06-15.
  55. ↑ Dony, John George, Flora of Hertfordshire (Hitchin 1967), p.80
  56. ↑ Photograph of an asymmetrical Hertfordshire elm, 'The Backs', River Lea, Ware, Herts. (from Hammerton, Wonderful Britain, 1920, vol.2): oreald.com
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