Ulmus minor 'Plotii'

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Ulmus minor
Plot Elm, Westonbirt, UK, before 1913.jpg
Plot's Elm, Westonbirt, before 1913
Cultivar 'Plotii'
Origin England

Ulmus minor 'Plotii', commonly known as Plot's Elm, or Lock Elm, is only found growing naturally in England, where it is encountered mainly in the East Midlands, notably around the River Witham in Lincolnshire and in the Trent Valley around Newark on Trent.[1] It has been described as Britain's rarest native elm, and it is recorded by The Wildlife Trust as a nationally scarce species.[2]

As with other members of the Field Elm group, the taxonomy of Plot's Elm has been a matter of contention, several authorities[3][4][5] 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.[6][7] After Richens had challenged the species idea, the tree was the subject of a study at the Royal Botanic Garden Edinburgh by Dr Max Coleman (2000), which showed that trees that were a perfect fit with the 'type' material of Plot elm were of a single clone (genetically identical to each other).[8] 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'.[9]

Henry miscalled the tree Goodyer's Elm. The trees Goodyer discovered were near the coast at Pennington, Hampshire, some 200 miles away and very dissimilar in structure.[10][11][12]

Description[edit]

Foliage of tree discovered at Laxton, Northamptonshire by Mr Matthew Ellis in 2013.

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[13] likened its appearance to an ostrich feather.[14] A single longish lower branch appears to have been a feature of its profile.

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.[15][16]

The samarae rarely ripen, but when mature are narrowly obovate, < 13 mm in length, with a triangular open notch.[10][11]

Pests and diseases[edit]

'Plotii' is very susceptible to Dutch elm disease.

Etymology[edit]

The tree was first recognized as a distinct form by the Oxford botanist George Claridge Druce in 1907-11,[17][18][19] who found examples at Banbury and Fineshade Abbey, and published descriptions with photographs.[20][21][22] Druce named the tree for Dr Robert Plot, a 17th-century English naturalist. The synonym 'Lock Elm' is an allusion to the difficulty in working its timber.[23] Bancroft referred to Plot's Elm as the East Anglian Elm, adding that it was often referred to as Wych Elm in the region;[24] however, she was almost certainly alluding to the Smooth-leaved Elm.

Cultivation[edit]

As the late-19th century specimen at Westonbirt Arboretum showed (mature by 1912 when Augustine Henry photographed it for his Trees of Great Britain & Ireland), the tree had been noted as distinctive and was being included in collections before it was classified botanically by George Claridge Druce (1911). Melville confirmed by field studies in the 1930s that Druce's specimens[25] were typical ('the type'),[26] 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] 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 would be 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".[8][28] Two aff. Plotii survive (2014) in the Royal Botanic Garden, Edinburgh.[29]

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.[2][30] Like other forms of the Field Elm, however, it suckers freely and is thus not considered critically endangered. Conservation measures are now in place to preserve known stands and to encourage propagation.[2]

Owing to its susceptibility to Dutch elm disease, Plot's Elm is no longer planted as an ornamental. The tree is not known in continental Europe, save three small specimens grown in a private garden at Seyne les Alpes, France.[31]

There are no known cultivars of this taxon, nor is it known to be in commerce in Europe.

Hybrids[edit]

Plot's Elm hybridizes in the wild both with wych elm,[1][32] 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.[1]

Hybrid cultivars[edit]

Elms of the Ulmus × viminalis group have been cultivated since at least 1677 [33] and have given rise to a hybrid cultivar of that name and to the cultivars 'Aurea', 'Marginata', 'Pulverulenta'.[34] The 19th-century cultivar 'Myrtifolia' was considered by Melville to be a probable U. minor × Ulmus minor subsp. plotii hybrid.[35] The 20th-century dwarf elm cultivar 'Jacqueline Hillier' is thought to belong to the 'Elegantissima' group.[36]

Notable trees[edit]

A mature avenue of the 'type' tree stood at Newton on Trent, Lincolnshire, in the early 20th century.[37]

A Plot-type elm, possibly the Westonbirt clone, with leaves that match both the diagnostic photographs of the type and (along with flowers and samarae) the illustrations in Stella Ross-Craig's diagram,[38] and with the characteristic inclination in the crown of its monopodial trunk (height 30m, girth 2.5m), survives (2014) on the Alvanley Terrace (Whitehouse Loan) side of Bruntsfield Links, Edinburgh.[39][40] Since this specimen, which has grown to maturity without apparent pruning or storm-damage, will have been selected by the plantsmen who turned The Meadows and Bruntsfield Links into an elm collection (it stands between Exeters and Huntingdons), it appears to have been planted as an example of Melville's 'species', though not of Druce's type-tree. Its probable date of planting, the mid-20th century, coincides with Melville's paper drawing attention to this peculiar British elm.

Accessions[edit]

North America
Europe

References[edit]

  1. ^ a b c Melville, Ronald, The Journal of Botany, London, Vol.78, Aug. 1940
  2. ^ a b c Plot’s Elm (Ulmus Plotii). Wildlifebcnp.org. Retrieved on 2011-05-24.
  3. ^ 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. 
  4. ^ Stace, C. A. (1997). New Flora of the British Isles, 2nd edition. Cambridge University Press.
  5. ^ 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. 
  6. ^ Richens, R. H., Elm, Cambridge 1983, p.54
  7. ^ Max Coleman, ed.: Wych Elm (Royal Botanic Garden Edinburgh publication, 2009; ISBN 978-1-906129-21-7); p. 22
  8. ^ a b 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. 
  9. ^ Coleman M. (2002) 'British elms.' British Wildlife 13 (6): 390-395.
  10. ^ a b Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland. Vol. VII. pp. 1848–1929. Private publication.
  11. ^ a b White, J. & More, D. (2002). Trees of Britain & Northern Europe. Cassell's, London.
  12. ^ 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
  13. ^ Richens, R. H. (1968). The correct designation of the European field elms. Feddes Repertorium 79: 1–2.
  14. ^ Photograph of young U. minor var. plotii in R. H. Richens, Elm (Cambridge 1983), p. 4
  15. ^ Photograph 1 of Plot's Elm leaves, elmer.rbge.org.uk
  16. ^ Photograph 2 of Plot's Elm leaves, elmer.rbge.org.uk
  17. ^ Botanical Exchange Club of the British Isles, report for 1907 (Oxford, 1908), p.258 archive.bsbi.org.uk/BEC_1907.pdf
  18. ^ Journal of the Northamptonshire Natural History Society, Vol. 16, December 1911
  19. ^ Gard. Chron. vol. 50 (1911 July-Dec.), p. 408, and vol. 51 (1912 Jan.-June), p. 35.
  20. ^ Gardeners' Chronicle photograph of Ulmus Plotii Druce near Fineshade, Northamptonshire, 'Plot Elms', www.plot-elms.co.uk [1]
  21. ^ Melville, Ronald, Journal of Botany (London, Aug. 1940)
  22. ^ Wilkinson, Gerald, Epitaph for the Elm (London, 1978)
  23. ^ Gurney, R. (1958). Trees of Britain. Faber & Faber, London.
  24. ^ Bancroft, H. (1934). Notes on the Status and Nomenclature of the British Elms. Gardeners' Chronicle XCVI.
  25. ^ Ulmus Plotii Druce near Fineshade, Northamptonshire, Gardeners' Chronicle, www.plot-elms.co.uk [2]
  26. ^ Melville, Ronald, The Journal of Botany, London, Vol.78, Aug. 1940
  27. ^ Wilkinson, Gerald, Epitaph for the Elm (London, 1978), p.74
  28. ^ Coleman M. (2002) 'British elms.' British Wildlife 13 (6): 390-395.
  29. ^ Photographs of supposed U. minor subsp. minor × U. minor var. plotii in RBGE, now described by RBGE as aff. Plotii; elmer.rbge.org.uk [3]
  30. ^ Wilkinson, Gerald, Epitaph for the Elm, London 1978, pp.72–74
  31. ^ Brookes, A. H. (2014). Disease-resistant elm cultivars, Butterfly Conservation trials report, 3rd revision, 2014. Butterfly Conservation, Hants & IoW Branch, England.
  32. ^ Richens, R. H., Elm, Cambridge 1983
  33. ^ Plot, Nat. Hist. Oxfordshire, 158, pl.10 fig.1 (1677)
  34. ^ Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London, p.659
  35. ^ Green, P. S. (1964). Registration of cultivar names in Ulmus. Arnoldia, Vol. 24. Arnold Arboretum, Harvard University. [4]
  36. ^ Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London, p.653
  37. ^ Plot Elm avenue, Newton on Trent, plot-elms.co.uk/plot-elm-images
  38. ^ Richens, R. H., Elm (Cambridge, 1983), Ch.7
  39. ^ Plot's Elm (centre), Bruntsfield Links, Edinburgh; henniker.org.uk
  40. ^ Plot's Elm, Bruntsfield Links, from Links Hotel (photo 50 of 81); tripadvisor.co.uk [5]
  41. ^ Johnson, Owen (ed.) (2003). Champion Trees of Britain & Ireland. Whittet Press, ISBN 978-1-873580-61-5.

External links[edit]