Ulmus rubra, the slippery elm, is a species of elm native to eastern North America. Other common names include red elm, gray elm, soft elm, moose elm, and Indian elm. It is closely related to the European wych elm ( U. glabra), which has a very similar flower structure but lacks the pubescence over the seed.[Elwes, H. J. & Henry, A. (1913). The Trees of Great Britain & Ireland . Vol. VII. 1862-4 (as U. fulva). Republished 2004 Cambridge University Press, ]
Description
Ulmus rubra is a medium-sized
deciduous tree with a spreading head of branches,
[Hillier & Sons. (1990). Hillier's Manual of Trees & Shrubs, 5th ed.. David & Charles, Newton Abbot, UK] commonly growing to , very occasionally over in height. Its
heartwood is reddish-brown. The broad oblong to obovate
leaves are long, rough above but velvety below, with coarse double-serrate margins, acuminate apices and oblique bases; the petioles are long.
[Bean, W. J. (1970). Trees & Shrubs Hardy in the British Isles, 8th ed., p. 656. (2nd impression 1976) John Murray, London. ] The leaves are often tinged red on emergence, turning dark green by summer and a dull yellow in autumn.
[ Missouri Botanical Garden, Ulmus rubra] The
perfect flower,
apetalous,
wind-pollinated flowers are produced before the leaves in early spring, usually in tight, short-stalked, clusters of 10–20. The reddish-brown
fruit is an oval winged samara, orbicular to obovate, slightly notched at the top, long, the single, central
seed coated with red-brown hairs, naked elsewhere.
The species superficially resembles
American elm (
Ulmus americana), but is chiefly distinguished from American elm by its downy twigs, chestnut brown or reddish hairy buds, and slimy red inner bark.
Taxonomy
The tree was first named as part of
Ulmus americana in 1753,
but identified as a separate species,
U. rubra, in 1793 by
Pennsylvania botanist Gotthilf Muhlenberg. The slightly later name
U. fulva, published by
France botanist André Michaux in 1803,
[Michaux, A. (1803). Flora Boreali-Americana ("The Flora of North America")] is still widely used in information related to dietary supplements and alternative medicine.
Etymology
The specific epithet
rubra (red), and the common name 'red elm', allude to the tree's reddish-brown heartwood, whilst the
common name 'slippery elm' alludes to the
mucilaginous inner bark.
Distribution and habitat
The species is native to eastern
North America, ranging from southeast
North Dakota, east to
Maine and southern
Quebec, south to northernmost
Florida, and west to eastern
Texas, where it thrives in moist uplands, although it will also grow in dry, intermediate soils.
Ecology
Pests and diseases
The tree is reputedly less susceptible to Dutch elm disease than other species of American elms,
but is severely damaged by the elm leaf beetle (
Xanthogaleruca luteola).
Hybridization in the wild
In the central United States, native
U. rubra hybridizes in the wild with the
Siberian elm (
U. pumila),
[Elowsky, C. G., Jordon-Thaden, I. E., & Kaul, R. B. (2013). A morphological analysis of a hybrid swarm of native Ulmus rubra and introduced U. pumila (Ulmaceae) in southern Nebraska. Phytoneuron 2013–44: 1–23. .] which was introduced in the early 20th century and has spread widely since, prompting conservation concerns for the genetic integrity of the former species.
['Conservation status of red elm ( Ulmus rubra) in the north-central United States', elm2013.ipp.cnr.it/downloads/book_of_abstracts.pdf. Cached pp. 33–35] The hybrid group is known as
Ulmus ×
intermedia.
Cultivation
The species has seldom been planted for ornament in its native country, though it occasionally appeared in early 20th-century US nursery catalogues.
[ Frederick W. Kelsey, Descriptive catalogue, no. 55, N.Y., 1906] Introduced to Europe in 1830,
and later to Australasia, it has never thrived in the UK; Elwes &
Augustine Henry knew of not one good specimen,
and the last tree planted at Kew attained a height of only in 60 years.
Specimens supplied by the Späth nursery of Berlin to the Royal Botanic Garden Edinburgh in 1902 as
U. fulva[ Sheet described as U. fulva; Sheet described as U. fulva, RBGE specimen from Späth nursery 1902] may survive in Edinburgh as it was the practice of the Garden to distribute trees about the city (
vide Wentworth Elm).
A specimen at RBGE was felled c.1990. The current list of Living Accessions held in the Garden
per se does not list the plant.
The tree was propagated and marketed in the UK by the Hillier & Sons nursery, Winchester, Hampshire, from 1945, with 20 sold in the period 1970 to 1976, when production ceased.
[Hillier & Sons (1977). Catalogue of Trees & Shrubs. Hillier, Ampfield, UK.][Hillier & Sons Sales inventory 1962 to 1977 (unpublished).] Several mature trees survive in
Brighton (see Accessions).
Cultivars
There are no known cultivars, though
Augustine Henry stated that the cultivar 'Heyderi', distributed by the Späth nursery of Berlin in the late 19th and early 20th centuries as a variety of
Ulmus elliptica, was, by some nursery error, propagated from an
Ulmus rubra.
[Henry John Elwes & Augustine Henry, The Trees of Great Britain & Ireland (1913), volume 7, p.1863–1864]
Meehan misnamed Ulmus americana 'Beebe's Weeping' as U. fulva pendula (1889) and Späth misnamed Ulmus americana 'Pendula' U. fulva (Michx.) pendula Hort. (1890). The hybrid U. rubra × U. pumila cultivar 'Lincoln' is sometimes erroneously listed as U. rubra 'Lincoln'.
Uses
Food
The
mucilaginous inner bark of the tree is edible raw or boiled,
and was eaten by Native Americans. The bark can also be used to make
tea.
Folk medicine
The inner bark is used orally in folk medicine to treat sore throat and gastrointestinal upset, and topically for skin rash and irritation.
The inner bark has long been used as a demulcent, and is still marketed commercially for this purpose in the United States as an over-the-counter demulcent.
Timber
The timber is not of much importance commercially, and is not found anywhere in great quantity.[Macoun, J. M. (1900). The Forest Wealth of Canada, p. 24. Canadian Commission for the Paris International Exhibition 1900.] and better suited for railway ties, fence-posts, and rails, while Gifford Pinchot recommended planting it in the Mississippi valley, as it grows fast in youth, and could be utilized for fence-posts when quite young, since the sapwood, if thoroughly dried, is quite as durable as the heartwood.[Pinchot, G. (1907). U S Forest Circular, no.85.] The wood is also used for the hubs of wagon wheels, as it is very shock resistant owing to the interlocking grain.
Baseball
Though now outmoded, slippery elm tablets were chewed by spitball pitchers to enhance the effectiveness of the saliva applied to make the pitched baseball curve. Gaylord Perry wrote about how he used slippery elm tablets in his 1974 autobiography, Me and the Spitter.
Miscellaneous
The tree's fibrous inner bark produces a strong and durable fiber that can be spun into thread, twine, or rope
Notable trees
A tree in Westmount, Quebec, Canada, measured in girth in 2011.[ Ulmus rubra, Cedar Crescent, Westmount, Quebec][ 'L'Orme Rouge ou l'Indian Elm de la rue Cedar Crescent'] The US national champion, measuring in circumference and tall, with an average crown spread of wide, grows in Kentucky.[Barnard, E. S. (2002) New York City Trees. New York: Columbia University Press. ]
Hybrid cultivars
U. rubra had limited success as a hybrid parent in the 1960s, resulting in the cultivars 'Coolshade', 'Fremont', 'Improved Coolshade', 'Lincoln', 'Rosehill', and probably 'Willis'.
Accessions
North America
-
Arnold Arboretum, US. Acc. nos. 737–88 (unrecorded provenance), 172-2017 (Massachusetts), 344-2017 (Missouri).
-
Bernheim Arboretum and Research Forest [6], Clermont, Kentucky, US. No details available.
-
Brenton Arboretum, Dallas Center, Iowa, US. No details available.
-
Chicago Botanic Garden, Glencoe, Illinois, US. 1 tree, no other details available.
-
Dominion Arboretum, Ottawa, Ontario, Canada. No acc. details available.
-
Longwood Gardens, US. Acc. no. L–3002, of unrecorded provenance.
-
Nebraska Statewide Arboretum, US. No details available.
-
Smith College, US. Acc. no. 8119PA.
-
U S National Arboretum [7], Washington, D.C., US. Acc. no. 77501.
Europe
-
Brighton & Hove City Council, UK. NCCPG Elm Collection.
-
Grange Farm Arboretum, Sutton St James, Spalding, Lincolnshire, UK. Acc. no. 522
-
Hortus Botanicus Nationalis, Salaspils, Latvia. Acc. nos. 18168, 18169, 18170.
-
of Uppsala, Sweden. Acc. no. 2009–0223. Wild collected in US.
-
Royal Botanic Gardens Wakehurst Place, UK. Acc. no. 1973–21050.
-
Thenford House arboretum, Northamptonshire, UK. No details available.
-
University of Copenhagen Botanic Garden, Denmark. No details available.
-
Wijdemeren city council, The Netherlands. One tree planted gardens Rading 1, Loosdrecht.
Australasia
-
Eastwoodhill Arboretum [8], Gisborne, New Zealand. 1 tree, no details available.
External links
