Ulmus 'Purpurea'

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Ulmus 'Purpurea'
Ulmus 'Purpurea'.jpg
'Purpurea', Warriston Cemetery, Edinburgh
Genus Ulmus
Cultivar 'Purpurea'
OriginEurope

The elm cultivar Ulmus 'Purpurea', the purple-leaved elm, was listed and described as Ulmus Stricta Purpurea, the 'Upright Purpled-leaved Elm', by John Frederick Wood, F.H.S., in The Midland Florist and Suburban Horticulturist (1851), [1] as Ulmus purpureaHort. by Wesmael (1863), [2] and as Ulmus campestris var. purpurea, syn. Ulmus purpureaHort. by Petzold and Kirchner in Arboretum Muscaviense (1864). [3] Koch's description followed (1872), [4] the various descriptions appearing to tally. Henry (1913) noted that the Ulmus campestris var. purpureaPetz. & Kirchn. grown at Kew as U. montana var. purpurea was "probably of hybrid origin", [5] Ulmus montana being used at the time both for wych elm cultivars and for some of the U. × hollandica group. His description of Kew's U. montana var. purpurea matches that of the commonly-planted 'Purpurea' of the 20th century. His discussion of it (1913) under U. campestris, however, his name for English Elm, may be the reason why 'Purpurea' is sometimes erroneously called U. procera 'Purpurea' (as in USA and Sweden ('Cultivation' and 'Accessions'). [6]

Contents

The fact that 'Purpurea' occasionally produces root-suckers confirms a hybrid origin with some U. minor component. F. J. Fontaine (1968) conjectured U. glabra × U. minor 'Stricta' and placed the tree in the U. × hollandica group under the name U. × hollandica 'Purpurascens', [7] [8] a name accepted by Royal Botanic Gardens Edinburgh [9] and in Australian publications. [10] [11] Hillier preferred U. × hollandica 'Purpurea', conjecturing 'Sarniensis' in its parentage. [12] The samarae, leaves and the habit of 'Purpurea' appear to support this conjecture.

See also 'Atropurpurea', possibly synonymous, raised by the Späth nursery in Berlin c.1881 and sometimes classed as a wych cultivar. [13] [14] [15]

Wych elm itself occasionally produces red- or purple-flushed new leaves, [16] the 19th century variety 'Corylifolia Purpurea' perhaps being an example. There is also a small-leaved elm U. minor 'Purpurascens' ( = Ulmus 'Myrtifolia Purpurea'), which nurseries listed and distributed separately from U. campestris purpureaHort.. [14] [17]

In North America, purple-leaved elms encountered in the fall are likely to be the new hybrid Ulmus 'Frontier'.

Description

Of Ulmus Stricta Purpurea Wood wrote (1851): "When young, the foliage is dark purple, in the way of the Purple Beech. As the season advances, it becomes somewhat greener, but always retains a distinct and peculiar character." [1] The leaves of Wesmael's (1863) Ulmus purpureaHort. were a "characteristic bronzy green" (canopy new leaves). [2] Those of Petzold and Kirchner's (1864) Ulmus campestris var. purpurea, syn. Ulmus purpureaHort., "emerged dark purple, later becoming more green, but always of a very dark, reddish-green which is peculiar". [3] Koch's U. purpurea (1872) had "leaves purple when young, changing to dark green". [18]

'Purpurea' grows to > 25 m in height, and is short-trunked with open, straggling, ascending branches. The leaf-buds are long, sharply pointed and dark purple, on shoots of the same colour. The flowers, too, emerge a uniform dark purple. The fruit, tinged purple over the seed, is intermediate between U. glabra and U. minor. The leaves, which are slightly folded, have a brief purplish-green flush in spring. The new leaves of lower bole-shoots and of suckers are pure dark purple, without any green. [19] [20] [21] After the spring flush, the leaves become olive green then darken in the summer. Their underside is paler, so that, with their increasing fold as the year progresses, the late-summer foliage has a greyish look. The bark of younger trees has a reddish-brown hue. [22]

Pests and diseases

The tree is susceptible to Dutch elm disease.

Cultivation

'Purpurea' Hort. was in cultivation in Europe from the 1860s. [3] [6] [23] [24] [25] Later, U. × hollandica 'Purpurascens' was "produced in quantity" by nurseries in Oudenbosch, the Netherlands. [7] [26] It is still present in Sweden, [27] [28] but appears to have been rarer in cultivation in the UK; Wilkinson in his researches for Epitaph for the Elm (1978) had never seen a specimen. In 2007 the Swedish Biodiversity Centre's 'Programme for Diversity of Cultivated Plants' included 'Purpurascens' (mistakenly called Ulmus procera 'Purpurea' in Sweden [27] ) in their plant conservation programme. [28]

Introduced to the USA in the late 1860s as Ulmus stricta purpurea, 'Purple leaved elm' was stocked by the Mount Hope Nursery (also known as Ellwanger and Barry) of Rochester, New York. [29] An U. campestris purpurea, 'Purple-leaved English Elm', of "compact upright growth" with "leaves a purple color in May and June", appeared in the 1902 catalogue of the Bobbink and Atkins nursery, Rutherford, New Jersey, [30] and an U. stricta purpurea, also called 'Purple-leaved English Elm', "a tree with erect branches and purplish-red leaves", in both Bobbink and Atkins' 1902 catalogue and Kelsey's 1904 catalogue, New York. [31] An elm obtained in 1922 from H. Kohankie & Son is listed by the Morton Arboretum, Illinois, as Ulmus procera 'Purpurea', [32] but without description. Its leaves do not flush purple. In arboretum photographs (2011) its bark and form do not appear to resemble hybrid 'Purpurea'. [33] [34]

In Australia cultivars by the name of U. glabraHuds. 'Purpurea', U. procera 'Purpurea' and U. purpurea appear in nursery catalogues dating from 1882; [35] these are now believed to be synonymous with the clone in cultivation there as U. × hollandica 'Purpurascens'. [10] [36] [37] 'Purpurascens' was sold by Searl's Garden Emporium, Sydney at the beginning of the 20th century and was "quite widely" planted in the south-east of the country, where it is said to tolerate dry conditions. [10] Urban plantings include avenue specimens and scattered trees in Fawkner Park, Melbourne. [38] [10]

Notable trees

A large specimen stands in Warriston Cemetery, Edinburgh (middle level). Six of the seven mature specimens growing there were felled in the 1990s; the seventh, near the east gate, remains healthy (2019) (height 20 m, bole-girth 2.2 m; labelled 03159 CEM). (Ignorance of this cultivar may have occasioned unnecessary felling: the tree's naturally upcurled, greyish foliage in late summer may be mistaken for foliage affected by Dutch elm disease.) A vigorous sucker in the cemetery has now become an established tree. In the Netherlands an old specimen, supplied by De Reebock nurseries in Oudenaarde, Belgium, stood until c.2010 in the Burgemeester Mijnlieffstraat in the town of Anna Paulowna. [39] In Australia the Avenue of Honour at Wallan, Victoria, was planted solely with 'Purpurascens' in the early 1920s, most of which survive, [40] and the cultivar was also included in the Avenue of Honour in Ballarat in 1918. [41] A large old purple-flushing elm stands in the gardens of the Hedvig Eleonora Church, Östermalm, Stockholm, with foliage appearing to match the hybrid purple elms in Edinburgh and Brighton. [42] [43] [44]

Synonymy

Accessions

Europe

Australasia

North America

Nurseries

Europe

Related Research Articles

<i>Ulmus minor</i> Stricta Elm cultivar

The field elm cultivar Ulmus minor 'Stricta', known as Cornish elm, was commonly found in South West England, Brittany, and south-west Ireland, until the arrival of Dutch elm disease in the late 1960s. The origin of Cornish elm in England remains a matter of contention. It is commonly assumed to have been introduced from Brittany. It is also considered possible that the tree may have survived the ice ages on lands to the south of Cornwall long since lost to the sea. Henry thought it "probably native in the south of Ireland". Dr Max Coleman of Royal Botanic Garden Edinburgh, arguing in his 2002 paper on British elms that there was no clear distinction between species and subspecies, suggested that known or suspected clones of Ulmus minor, once cultivated and named, should be treated as cultivars, preferred the designation U. minor 'Stricta' to Ulmus minor var. stricta. The DNA of 'Stricta' has been investigated and the cultivar is now known to be a clone.

The hybrid elm cultivar Ulmus × hollandica 'Dauvessei', one of a number of cultivars arising from the crossing of the Wych Elm U. glabra with a variety of Field Elm U. minor, is a very rare cultivar said to have originated at the D. Dauvesse nursery in Orléans, France before 1877.

The elm cultivar Ulmus 'Atropurpurea' [:dark purple] was raised from seed at the Späth nursery in Berlin, Germany, circa 1881, as Ulmus montana atropurpurea, and was marketed there till the 1930s, being later classed as a cultivar by Boom. Henry (1913) included it under Ulmus montana cultivars but noted that it was "very similar to and perhaps identical with" Ulmus purpureaHort. At Kew it was renamed U. glabraHuds. 'Atropurpurea', but Späth used U. montana both for wych elm and for some U. × hollandica hybrids, so his name does not necessarily imply a wych elm cultivar. The Hesse Nursery of Weener, Germany, however, which marketed 'Atropurpurea' in the 1950s, listed it in later years as a form of U. glabraHuds..

<i>Ulmus</i> Crispa Elm cultivar

The elm cultivar Ulmus 'Crispa' [:'curled', the leaf margin], sometimes known as the Fernleaf Elm, arose before 1800 and was first listed by Willdenow as U. crispa (1809). Audibert listed an U. campestrisLinn. 'Crispa', orme à feuilles crépues [:'frizzy-leaved elm'], in 1817, and an Ulmus urticaefolia [:'nettle-leaved elm'] in 1832; the latter is usually taken to be a synonym. Loudon considered the tree a variety of U. montana (1838). In the 19th century, Ulmus × hollandica cultivars, as well as those of Wych Elm, were often grouped under Ulmus montana. Elwes and Henry (1913) listed 'Crispa' as a form of wych elm, but made no mention of the non-wych samara.

The elm cultivar Ulmus 'Monstrosa' [: "monstrous", "strange"], a shrub-elm with fasciated branching, is believed to have originated in France, where it was first listed by Lavallée in Arboretum Segrezianum (1877) as a form of Field Elm, Ulmus campestris var. monstrosa, but without description. Though its long slender 2 cm petiole is not a feature of wych elm U. glabraHuds., and is even less likely in a shrub form of this species, the wych-cultivar error arose early, perhaps because the Späth nursery of Berlin, using Ulmus montana both for some Ulmus × hollandica cultivars and for wych varieties, listed it c.1890 as Ulmus montana monstrosa. Hartwig in Illustrirtes Gehölzbuch (1892) followed with Ulmus scabra monstrosa, an error repeated by Krüssman (1962) and by Green (1964), with their U. glabraHuds. 'Monstrosa'.

<i>Ulmus minor</i> Webbiana Elm cultivar

The Field Elm cultivar Ulmus minor 'Webbiana', or Webb's curly-leaf elm, distinguished by its unusual leaves that fold upwards longitudinally, was said to have been raised at Lee's Nursery, Hammersmith, London, circa 1868, and was first described in that year in The Gardener's Chronicle and The Florist and Pomologist. It was marketed by the Späth nursery of Berlin in the late 19th and early 20th centuries as U. campestris WebbianaHort., and by Louis van Houtte of Ghent as U. campestris crispa (Webbiana). Henry thought 'Webbiana' a form of Cornish Elm, adding that it "seems to be identical with the insufficiently described U. campestris var. concavaefoliaLoudon" – a view repeated by Krüssmann.

The putative Wych Elm cultivar Ulmus glabra 'Corylifolia' was first described by Host in Flora Austriaca (1827). Another cultivar of the same name is described by Hugo Zapalowicz in Conspectus Florae Galiciae Criticus (1908), but was assumed to be 'Cornuta'. Herbarium specimens confirm that more than one clone has been labelled 'Corylifolia', some with longish petioles and with fruit more typical of Ulmus × hollandica hybrids.

The Wych Elm cultivar Ulmus glabra 'Corylifolia Purpurea' was raised from seed of 'Purpurea' and described as U. campestris corylifolia purpurea by Pynaert in 1879. An U. campestris corylifolia purpurea was distributed by the Späth nursery of Berlin in the late 19th and early 20th centuries. The Hesse Nursery of Weener, Germany, corrected the U. campestris corylifolia purpurea of their 1930s' lists to U. glabraHuds.corylifolia purpurea by the 1950s. Green listed 'Corylifolia Purpurea' as a form of U. glabra.

The putative Wych Elm cultivar Ulmus glabra 'Latifolia Nigricans' was first described, as Ulmus campestris latifolia nigricans, by Pynaert in 1879. Pynaert, however, did not specify what species he meant by U. campestris. The tree was supplied by the Späth nursery of Berlin in the late 19th century and early 20th as Ulmus montana latifolia nigricans. Späth, like many of his contemporaries, used U. montana both for Wych Elm cultivars and for those of the U. × hollandica group.

The elm cultivar Ulmus 'Tortuosa'Host, the Wiggly Elm, was described by Host in Flora Austriaca (1827) as Ulmus tortuosa, from low, twisted, small-leaved trees that grew in the hilly districts of Hungary. A contemporary herbarium specimen (1833) from Central Europe labelled U. tortuosaHost appears to show small field elm-type leaves. Henry distinguished 'Tortuosa' Host from Loddiges' and Loudon's U. tortuosa, which he identified with Ulmus 'Modiolina', "l'orme tortillard" of France. Henry noted, however, that abnormal sinuous or zigzagging growth "might occur in any kind of elm", and herbarium specimens of elms labelled 'Tortuosa' range from U. minor cultivars to hybrid cultivars, some treated as synonymous with 'Modiolina'. A large-leaved U. campestris tortuosa was described by David in Revue horticole (1846), while a hybrid var. tortuosa cultivar from Louveigné, Belgium, with twisted trunk and large leaves, was described by Aigret in 1905. An U. campestris suberosa tortuosa was marketed in the 1930s by the Hesse Nursery of Weener, Germany, by its description a contorted form of corky-barked field elm.

The elm cultivar Ulmus 'Myrtifolia', the Myrtle-leaved Elm, first appeared in nursery and horticultural lists from the 1830s, as Ulmus myrtifolia and Ulmus campestris myrtifolia, the name Ulmus myrtifoliaVolxem being used at Kew Gardens from 1880. Lawson's nursery of Edinburgh appears to have been the earliest to list the tree. 'Myrtifolia' was listed by Nicholson in Kew Hand-List Trees & Shrubs (1896), but without description. It was later listed as a cultivar and described by Rehder in 1939 and by Krüssmann in 1962.

<i>Ulmus glabra</i> Latifolia Elm cultivar

The putative Wych Elm cultivar Ulmus glabra 'Latifolia' was identified in Audibert's Tonelle (1817) as U. campestrisLinn. [ = U. glabraHuds.] latifolia. The tree is reputed to have originated circa 1750 in or around Mechelen, and to have been widely planted throughout Belgium. A 1912 herbarium specimen from Oudenbosch, however, shows a hybrid leaf labelled Ulmus hollandica latifolia.

The hybrid elm cultivar Ulmus × hollandica 'Modiolina', or Wheel-hub elm, was probably the large-leaved 'Orme tortillard' first described by Duhamel in De l'exploitation des bois (1764). Poederlé (1774) identified the tree as the 'orme maigre' growing in the region that later became part of Belgium. Dumont de Courset described a small-leaved U. campestris var. modiolina, "l'orme tortillard" in 1802 – the first use of the name 'Modiolina'. 'L'orme Tortillard', also known as 'l'orme à moyeux', was considered in France to be the best elm for use by wheelwrights, its timber especially suitable for hubs of wheels. Van Houtte marketed an U. campestris modiolina (tortuosa), and Späth an U. campestris modiolina, from the late 19th century. U. campestris var. modiolinaHort was confirmed as a hybrid by Chevalier in Les Ormes de France (1942) and called U. × 'Modiolina', 'l'orme à moyeux'.

<i>Ulmus minor</i> Purpurascens Elm cultivar

The Field Elm cultivar Ulmus minor 'Purpurascens' was listed by Lavallée in Arboretum Segrezianum (1877) as U. campestris var. purpurascens (purpurea), but without description, and later by Schneider in Illustriertes Handbuch der Laubholzkunde (1904). Krüssmann in Handbuch der Laubgehölze (1962) identified it as a cultivar.

<i>Ulmus minor</i> Pendula Elm cultivar

The Field Elm cultivar Ulmus minor 'Pendula' was said to have been raised in Belgium in 1863. It was listed as Ulmus sativa pendula by C. de Vos in 1887, and by Boom in 1959 as a cultivar.

<i>Ulmus</i> × <i>hollandica</i> Wentworthii Pendula Elm cultivar

Ulmus × hollandica 'Wentworthii Pendula', commonly known as the Wentworth Elm or Wentworth Weeping Elm, is a cultivar with a distinctive weeping habit that appears to have been introduced to cultivation towards the end of the 19th century. The tree is not mentioned in either Elwes and Henry's or Bean's classic works on British trees. The earliest known references are Dutch and German, the first by de Vos in Handboek tot de praktische kennis der voornaamste boomen (1890). At about the same time, the tree was offered for sale by the Späth nursery of Berlin as Ulmus Wentworthi pendulaHort.. The 'Hort.' in Späth's 1890 catalogue, without his customary label "new", confirms that the tree was by then in nurseries as a horticultural elm. De Vos, writing in 1889, states that the Supplement to Volume 1 includes entries announced since the main volume in 1887, putting the date of introduction between 1887 and 1889.

<i>Ulmus minor</i> Viminalis Elm cultivar

The field elm cultivar Ulmus minor 'Viminalis' (:'willow-like'), occasionally referred to as the twiggy field elm, was raised by Masters in 1817, and listed in 1831 as U. campestris viminalis, without description. Loudon added a general description in 1838, and the Cambridge University Herbarium acquired a leaf specimen of the tree in 1866. Moss, writing in 1912, said that the Ulmus campestris viminalis from Cambridge University Herbarium was the only elm he thought agreed with the original Plot's elm as illustrated by Dr. Plot in 1677 from specimens growing in an avenue and coppice at Hanwell near Banbury. Elwes and Henry (1913) also considered Loudon's Ulmus campestris viminalis to be Dr Plot's elm. Its 19th-century name, U. campestris var. viminalis, led the cultivar to be classified for a time as a variety of English Elm. On the Continent, 'Viminalis' was the Ulmus antarcticaHort., 'zierliche Ulme' [:'dainty elm'] of Kirchner's Arboretum Muscaviense (1864).

<i>Ulmus</i> Myrtifolia Purpurea Elm cultivar

The Elm cultivar Ulmus 'Myrtifolia Purpurea', the Purple Myrtle-leaved Elm, was first mentioned by Louis de Smet of Ghent (1877) as Ulmus myrtifolia purpurea. An U. campestris myrtifolia purpureaHort. was distributed by Louis van Houtte in the 1880s, by the Späth nursery, Berlin, in the 1890s and early 1900s, and by the Hesse Nursery, Weener, Germany, till the 1930s.

<i>Ulmus glabra</i> Concavaefolia Elm cultivar

The Wych Elm cultivar Ulmus glabra 'Concavaefolia', a form with up-curling leaves, was listed in Beissner's Handbuch der Laubholz-Benennung (1903) as Ulmus montana cucullataHort. [:'hooded', the leaf], a synonym of the Ulmus scabraMill. [:glabraHuds.] var. concavaefolia of herbarium specimens. An Ulmus campestris cucullata, of uncertain species, had appeared in Loddiges' 1823 list, but Loudon's brief description (1838) of concave- and hooded-leaved elms was insufficient for later botanists to distinguish them. The earliest unambiguous description appears to be that of Petzold and Kirchner in Arboretum Muscaviense (1864).

<i>Ulmus glabra</i> Superba Elm cultivar

The wych elm cultivar Ulmus glabraHuds. 'Superba', Blandford Elm, with unusually large leaves, was raised by Gill's of Blandford Forum, Dorset, in the early 1840s as Ulmus montana superba and was quickly distributed to other UK nurseries. It was confirmed as a form of wych, and first described by Lindley in The Gardeners' Chronicle, 1845, later descriptions being added by Gill (1845) and Morren (1848), who called it U. montana var. superba. Morren had adopted the name 'Superba' from the Fulham nurseryman Osborne in 1844, who supplied him with the tree – presumably one of the nurseries supplied by Gill. Morren states that 'Superba', already in cultivation in England, was introduced to Belgium by Denis Henrard of Saint Walburge, Liège, that in 1848 it had been present in Belgium for only three years, and that this variety was the one described as 'Superba' by Osborne, whom Henrard had visited at his nursery in Fulham in September 1844. 'Blandford Elm', with leaves of the same dimensions, was soon for sale in the USA.

References

  1. 1 2 Wood, John Frederick (1852). "Coppiceana". The Midland Florist and Suburban Horticulturist. London. 6: 365.
  2. 1 2 Wesmael, Alfred, Bulletin de la Fédération des sociétés d'horticulture de Belgique 1862: (Ghent, 1863), p.390
  3. 1 2 3 Petzold and Kirchner in Arboretum Muscaviense (Gotha, 1864), p.557
  4. ↑ Koch, K. Dendrologie; Bäume, Sträucher und Halbsträucher, welche in Mittel- und Nord- Europa im Freien kultivirt werden 2 (1), 416 (1872)
  5. ↑ Elwes, Henry John; Henry, Augustine (1913). The Trees of Great Britain & Ireland. Vol. 7. p. 1905.
  6. 1 2 3 Elwes, Henry John; Henry, Augustine (1913). The Trees of Great Britain & Ireland. Vol. 7. p. 1868.
  7. 1 2 F. J., Fontaine (1968). "Ulmus". Dendroflora. 5: 37–55. Retrieved 30 August 2017.
  8. 1 2 3 Bean, W. J. (1988) Trees and shrubs hardy in Great Britain, 8th edition, Murray, London, p. 640 (under U. angustifolia
  9. ↑ Kemp, Eddie (1979). "The Plantsman's Elm". In Clouston, Brian; Stansfield, Kathy (eds.). After the Elm. London: William Heinemann Ltd. p. 35. ISBN   9780434139002.
  10. 1 2 3 4 Spencer, Roger, ed., Horticultural Flora of South-Eastern Australia, Vol. 2 (Sydney, 1995), Ulmus, p.111
  11. ↑ Spencer, R., Hawker, J. and Lumley, P. (1991). Elms in Australia. Royal Botanic Gardens, Melbourne. ISBN   0724199624.
  12. ↑ Hilliers' Manual of Trees & Shrubs (Winchester, 1973), p.402
  13. ↑ Green, Peter Shaw (1964). "Registration of cultivar names in Ulmus". Arnoldia. Arnold Arboretum, Harvard University. 24 (6–8): 41–80. Retrieved 16 February 2017.
  14. 1 2 Katalog (PDF). Vol. 108. Berlin, Germany: L. Späth Baumschulenweg. 1902–1903. pp. 132–133.
  15. ↑ Späth, Ludwig (1930). Späth-Buch, 1720-1930. Berlin: Self published. pp. 311–313, 351–352.
  16. ↑ "Inglise jalakas ´Purpurea´" [Purple English Elm]. jarvselja.ee (in Estonian). Retrieved 2017-08-31.
  17. ↑ Catalogue of the trees and shrubs in the arboretum and botanic gardens at the central experimental farm (2nd ed.). 1899. p. 75.
  18. ↑ "Herbarium specimen - L.1581936". Botany catalogues. Naturalis Biodiversity Center. Sheet labelled U. proceraSalisb. var. stricta purpurea (Arnold Arboretum specimen, 1930); "Herbarium specimen - L.1581933". Botany catalogues. Naturalis Biodiversity Center. Sheet labelled U. proceraSalisb. var. purpureaRehder (Arnold Arboretum specimen, 1930); "Herbarium specimen - WAG.1847116". Botany catalogues. Naturalis Biodiversity Center. Sheet labelled U. × hollandica var. purpurea; "Herbarium specimen - L.1590639". Botany catalogues. Naturalis Biodiversity Center. Sheet labelled U. campestris L. complicata (Baenitz) (Breslau, 1903) (?); Herbarium specimen of U. montana purpurea, science.udau.edu.ua
  19. ↑ Photograph of newly emerged leaves of 'Purpurea' in Denmark, www.loenbaek.dk
  20. ↑ Emerging 'Purpurea' leaves photographed against sunlight, www.kuningas.ee
  21. ↑ Photograph of 'Purpurea' cuttings, www.kuningas.ee
  22. ↑ Spencer, Roger, ed., Horticultural Flora of South-Eastern Australia, Vol. 2 (Sydney, 1995), Ulmus, p.112
  23. ↑ Anthony waterer's catalogue. 1880. p. 20.
  24. ↑ Cultures de Louis van Houtte: Plantes Vivaces de Pleine Terre, Catalogue de Louis van Houtte, 1881-2, p.303
  25. ↑ 'Standard Ornamental Trees' in Forest, hardy ornamental trees, conifers, etc., Richard Smith & Co., Worcester, 1887–88, p.27
  26. ↑ E. E. Kemp (Curator, Royal Botanic Garden Edinburgh 1950-71) in After the Elm, eds. Clouston & Stansfield, (London, 1979), p.35
  27. 1 2 Lagerstedt, Lars (2014). "Märkesträd i Sverige - 10 Almar" [Notable trees in Sweden - 10 Elms](PDF). Lustgården. 94: 60, 71, 76. Retrieved 15 May 2018.
  28. 1 2 Leaves and samarae of 'Purpurascens', 'Programme for Diversity of Cultivated Plants', Sweden, pom.info,
  29. ↑ Ellwanger & Barry, Descriptive Catalogue of Hardy Ornamental Trees ... at the Mount Hope Nurseries (Rochester, N.Y., 1868), p.9
  30. ↑ Bobbink and Atkins, Rutherford. N.J. 1902. p. 51.
  31. ↑ General catalogue, 1904 : choice hardy trees, shrubs, evergreens, roses, herbaceous plants, fruits, etc. New York: Frederick W. Kelsey. 1904. p. 18.
  32. ↑ Ulmus procera 'Purpurea': Morton Arboretum Catalogue, Accession no. 593–22
  33. ↑ " U. procera 'Purpurea' ", acorn.mortonarb.org
  34. ↑ Photographs of " U. procera 'Purpurea' " from H. Kohankie & Son, at Morton Arboretum (2011); 'Ulmus Series', acorn.mortonarb.org
  35. ↑ Brookes, Margaret, & Barley, Richard, Plants listed in nursery catalogues in Victoria, 1855-1889 (Ornamental Plant Collection Association, South Yarra, Victoria, 1992), p.303–304
  36. ↑ Spencer, R.; Hawker, J. & Lumley, P. (1991). Elms in Australia. Australia: Royal Botanic Gardens, Melbourne. ISBN   0-7241-9962-4.
  37. ↑ Sibbing, Nick. "Significant Elms of South-Eastern Australia". advancedtrees.com.au. Retrieved 2017-06-19.
  38. ↑ 'Purpurascens' in Fawkner Park, Melbourne: elsewhere.polydistortion.net
  39. ↑ Google Maps: Burgemeester Mijnlieffstraat Google Maps (July 2009), accessdate: November 3, 2020
  40. ↑ Photographs of 'Purpurascens', Avenue of Honour, Wallan, Victoria: vhd.heritage.vic.gov.au
  41. ↑ ballarat.com Archived 2014-04-13 at the Wayback Machine
  42. ↑ www.tradgardsakademin.se
  43. ↑ Photograph of purple-flushing elm, Hedvig Eleonora Church, Stockholm (to right of church)
  44. ↑ Aerial photograph of Hedvig Eleonora Church, the dark crown of purple-flushing elm visible near the east window
  45. ↑ National Elm Collection list www.brighton-hove.gov.uk/index.cfm?request=c1108042
  46. ↑ Centrum voor Botanische Verrijking vzw: Voorraadlijst, accessdate: November 2, 2016
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