Platanus × acerifolia

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Platanus ×acerifolia
Berkeley Square - geograph.org.uk - 911963.jpg
London plane trees in Berkeley Square, London, planted 1789
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Proteales
Family: Platanaceae
Genus: Platanus
Species:
P. ×acerifolia
Binomial name
Platanus ×acerifolia
Synonyms [1]
  • Platanus orientalis var. acerifoliaAiton [basionym]
  • Platanus × acerifolia f. pyramidalis(Bolle ex Janko) C.K.Schneid.
  • Platanus × acerifolia f. suttneri(Jaennicke) C.K.Schneid.
  • Platanus × acerifolia var. hispanicaauct. non Mill. ex Münchh., nom. dub.
  • Platanus × acerifolia var. kelseyana(Jaennicke) C.K.Schneid.
  • Platanus × hispanicaauct. non Mill. ex Münchh., nom. dub.
  • Platanus × hybridaBrot.

Platanus × acerifolia, Platanus × hispanica, or hybrid plane, is a tree in the genus Platanus . It is often known by the synonym London plane [2] or London planetree. It is a hybrid of Platanus orientalis (oriental plane) and Platanus occidentalis (American sycamore).

Platanus x hispanica Arboles de Platanos.jpg
Platanus x hispanica
Hybrid plane trees in Villa del Parque Train Station, Buenos Aires Arboles de Platanos (2).jpg
Hybrid plane trees in Villa del Parque Train Station, Buenos Aires

Description

London plane in NMSU London Plane Whole.jpg
London plane in NMSU

The London plane is a large deciduous tree growing 20–30 m (65–100 ft), exceptionally over 40 m (130 ft) tall, with a trunk up to 3 m (10 ft) or more in circumference. The bark is usually pale grey-green, smooth and exfoliating, or buff-brown and not exfoliating. The leaves are thick and stiff-textured, broad, palmately lobed, superficially maple-like, the leaf blade 10–20 cm (4–8 in) long and 12–25 cm (5–10 in) broad, with a petiole 3–10 cm (1–4 in) long. The young leaves in spring are coated with minute, fine, stiff hairs at first, but these wear off and by late summer the leaves are hairless or nearly so. The flowers are borne in one to three (most often two) dense spherical inflorescences on a pendulous stem, with male and female flowers on separate stems. The fruit matures in about 6 months, to 2–3 centimetres (0.8–1.2 in) diameter, and comprises a dense spherical cluster of achenes with numerous stiff hairs which aid wind dispersal; the cluster breaks up slowly over the winter to release the numerous 2–3 mm (0.08–0.12 in) seeds. The London Plane is one of the most efficient trees in removing small particulate pollutants in urban areas. [3]

It shares many visual similarities with Platanus occidentalis (American sycamore), from which it is derived; however, the two species are relatively easy to distinguish, considering the London plane is almost exclusively planted in urban habitats, while P. occidentalis is most commonly found growing in lowlands and alluvial soils along streams. [4]

Origin

London plane in Whittier College London plane summer.jpg
London plane in Whittier College

The species was formed by hybridization in the 17th century after P. orientalis and P. occidentalis had been planted in proximity to one another. It is often said that the hybridization took place in Spain, but it could also have happened in Vauxhall Gardens in London where John Tradescant the Younger discovered the tree in the mid-17th century. [5] [6] The leaf and flower characteristics are intermediate between the two parent species, the leaf being more deeply lobed than P. occidentalis but less so than P. orientalis, and the seed balls typically two per stem (one in P. occidentalis, 3–6 in P. orientalis). The hybrid is fertile, and seedlings are occasionally found near mature trees.

Controlled reciprocal pollinations between P. occidentalis and P. orientalis resulted in good yields of germinable seed and true hybrid seedlings. Crosses of both species, as females, with P. racemosa and P. wrightii produced extremely low yields of germinable seed, but true hybrids were obtained from all interspecific combinations. Apomixis (asexual reproduction from non-fertilized seeds) appeared common in P. orientalis. [7]

In 1968 and 1970, Frank S. Santamour Jr. recreated the P. orientalis by P. occidentalis cross using a P. orientalis of Turkish origin with American sycamores (P. occidentalis). The offspring were evaluated following several years of exposure to anthracnose infection. Two selections, 'Columbia' and 'Liberty', were released in August, 1984. [7] [8]

Taxonomy

This example, Topcider Park, Belgrade, was planted in 1834. London Plane, Topcider Park, Belgrade.JPG
This example, Topčider Park, Belgrade, was planted in 1834.

Platanus × acerifolia was first formally described in the botanical literature by the Scottish botanist William Aiton in his 1789 work Hortus Kewensis as a variety of P. orientalis. [9] Aiton described this variety with a two-word Latin diagnosis, "foliis transversis", and called it the Spanish plane tree. [10] In 1805, Carl Ludwig Willdenow chose to elevate Aiton's variety to species rank, publishing the new species P. acerifolia in the fourth edition of Species Plantarum . [11] [12] The species name was then modified to include the multiplication symbol to indicate its suspected hybrid parentage. The other name commonly used for this taxon, Platanus × hispanica auct. non Mill. ex Münchh., is a nomen dubium based on an uncertain description. [13] [14]

Cultivation

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Avenue of London plane trees on Jesus Green

The London plane is one of 50 Great British Trees that the Tree Council selected in 2002 in honour of Queen Elizabeth II's Golden Jubilee. [15] The list specifically mentions Britain's first London plane being in the city of Ely, Cambridgeshire.

The London plane is very tolerant of atmospheric pollution and root compaction, and for this reason it is a popular urban roadside tree. It was planted extensively in Victorian times to weather the pollution of London. It is now extensively cultivated in most temperate latitudes as an ornamental and parkland tree, and is a commonly planted tree in cities throughout the temperate regions of the world, in London and many other cities. [5] It has a greater degree of winter cold tolerance than P. orientalis, and is less susceptible to anthracnose disease than P. occidentalis. Under the synonym Platanus × hispanica, the tree has gained the Royal Horticultural Society of Great Britain's Award of Garden Merit. [16] [17]

The tree is fairly wind-resistant. However, it has a number of problems in urban use, most notably the short, stiff hairs shed by the young leaves and the dispersing seeds; these are an irritant if breathed in, and can exacerbate breathing difficulties for people with asthma. The large leaves can create a disposal problem in cities, as they are tough and sometimes can take more than one year to break down if they remain whole.

London planes are often pruned by a technique called pollarding. A pollarded tree has a drastically different appearance than an unpruned tree, being much shorter with stunted, club-like branches. Although pollarding requires frequent maintenance (the trees must usually be repruned every year), it creates a distinctive shape that is often sought after in plazas, main streets, and other urban areas.

In New York City

According to the New York City Department of Parks and Recreation the symbol of that organization is a cross between the leaf of the London plane and a maple leaf. It is prominently featured on signs and buildings in public parks across the city. The tree is on the NYC Parks Department's list of restricted use species for street tree planting, because it constitutes more than 10% of all street trees.

In Australia

In Australia, the London plane is used extensively as a street tree in major cities, particularly Sydney, Melbourne, Adelaide and Perth. The tree is commonly used because of its resilience to warm weather, its benefits as a shade tree, resistance to breakage and tolerance of urban pollution.

In Johannesburg, South Africa

In Johannesburg, South Africa many London planes line streets in older suburbs. In recent years the trees have been infested with the Polyphagous shot hole borer beetle. Some trees are reportedly developing resistance mechanisms but there are currently no effective measures against the borer beetle and it remains unclear how many trees will have to be cut down. [18]

In China

The London plane is cultivated in Central, Northeastern and Southern China. [9]

Timber

When quarter-sawn, the timber has a distinctive and highly decorative appearance of dark reddish-brown flecks against a lighter background and is known as lacewood. [19]

Cultivars

Related Research Articles

<span class="mw-page-title-main">Hybrid (biology)</span> Offspring of cross-species reproduction

In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera. Hybrids are not always intermediates between their parents, but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are.

Sycamore is a name which has been applied to several types of trees, but with somewhat similar leaf forms. The name derives from the ancient Greek συκόμορος (sūkomoros) meaning "fig-mulberry".

<span class="mw-page-title-main">Platanaceae</span> Family of flowering plants

Platanaceae, the "plane-tree family", is a family of flowering plants in the order Proteales. The family consists of only a single extant genus Platanus, with twelve known species. The plants are tall trees, native to temperate and subtropical regions of the Northern Hemisphere. The hybrid London plane is widely planted in cities worldwide.

<i>Platanus</i> Genus of flowering plants constituting the family Platanaceae

Platanus is a genus consisting of a small number of tree species native to the Northern Hemisphere. They are the sole living members of the family Platanaceae.

<i>Thuja</i> Genus of conifers

Thuja is a genus of coniferous tree or shrub in the Cupressaceae. There are five species in the genus, two native to North America and three native to eastern Asia. The genus is monophyletic and sister to Thujopsis. Members are commonly known as arborvitaes, thujas or cedars.

<i>Cornus florida</i> Species of flowering plant in the dogwood family Cornaceae

Cornus florida, the flowering dogwood, is a species of flowering tree in the family Cornaceae native to eastern North America and northern Mexico. An endemic population once spanned from southernmost coastal Maine south to northern Florida and west to the Mississippi River. The tree is commonly planted as an ornamental in residential and public areas because of its showy bracts and interesting bark structure.

<i>Malus</i> Flowering genus, rose family Rosaceae

Malus is a genus of about 32–57 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples and wild apples.

<i>Platanus orientalis</i> Tree

Platanus orientalis, the Old World sycamore or Oriental plane, is a large, deciduous tree of the Platanaceae family, growing to 30 m (98 ft) or more, and known for its longevity and spreading crown. In autumn its deep green leaves may change to blood red, amber, and yellow.

<i>Platanus occidentalis</i> Species of plant

Platanus occidentalis, also known as American sycamore, American planetree, western plane, occidental plane, buttonwood, and water beech, is a species of Platanus native to the eastern and central United States, the mountains of northeastern Mexico, extreme southern Ontario, and extreme southern Quebec. It is usually called sycamore in North America, a name which can refer to other types of trees in other parts of the world. The American sycamore is a long-lived species, typically surviving at least 200 years and likely as long as 500–600 years.

<i>Platanus racemosa</i> Species of tree

Platanus racemosa is a species of plane tree known by several common names, including California sycamore, western sycamore, California plane tree, and in North American Spanish aliso. Platanus racemosa is native to California and Baja California, where it grows in riparian areas, canyons, floodplains, at springs and seeps, and along streams and rivers in several types of habitats. It can be found as far north as Tehama and Humboldt counties.

<i>Acer pseudoplatanus</i> Species of flowering plant in the lychee family Sapindaceae

Acer pseudoplatanus, known as the sycamore in the British Isles and as the sycamore maple in the United States, is a species of maple native to Central Europe and Western Asia. It is a large deciduous, broad-leaved tree, tolerant of wind and coastal exposure.

<i>Salix babylonica</i> Species of tree

Salix babylonica is a species of willow native to dry areas of northern China, but cultivated for millennia elsewhere in Asia, being traded along the Silk Road to southwest Asia and Europe.

<i>Vitis rupestris</i> Species of grapevine

Vitis rupestris is a species of grape native to the United States that is known by many common names including July, Coon, sand, sugar, beach, bush, currant, ingar, rock, and mountain grape. It is used for breeding several French-American hybrids as well as many root stocks.

<i>Leucadendron</i> Genus of flowering plants in the family Proteaceae, endemic to South Africa

Leucadendron is a genus of about 80 species of flowering plants in the family Proteaceae, endemic to the Cape Provinces and KwaZulu-Natal in South Africa, where they are a prominent part of the fynbos ecoregion and vegetation type.

<i>Ulmus pumila</i> Hansen Elm cultivar

The Siberian elm cultivar Ulmus pumila 'Hansen' is a little-known American tree of obscure origin, possibly raised from seed collected by the horticulturist and botanist Prof. Niels Hansen during his expedition to Siberia in 1897.

<i>Ulmus</i> Den Haag Elm cultivar

The hybrid elm cultivar Ulmus 'Den Haag' is a Dutch development derived from a chance crossing of the Siberian Elm cultivar Ulmus pumila 'Pinnato-ramosa' and the Belgian Elm Ulmus × hollandica 'Belgica'. S. G. A. Doorenbos (1891-1980), Director of Public Parks in The Hague, finding that seeds he had sown in 1936 from the Zuiderpark 'Pinnato-ramosa' had hybridized with the local 'Belgica', selected six for trials. The best was cloned and grafted on 'Belgica' rootstock as 'Den Haag'; it was planted first in that city, then released to nurseries elsewhere in the Netherlands. The other five were also planted in The Hague.

<i>Corythucha ciliata</i> Species of true bug

Corythucha ciliata, the sycamore lace bug, is a species of lace bug in the family Tingidae that is associated with sycamore trees.

<i>Ceratocystis platani</i> Species of fungus

Ceratocystis platani is a fungus that causes a disease on plane trees in the genus Platanus, mostly in North America and Southern Europe.

<i>Lathyrus belinensis</i> Species of legume

Lathyrus belinensis, also known as the Belin pea is a flowering plant species in the genus Lathyrus under the family Fabaceae. The species was discovered in Turkey by botanists Nigel Maxted and David John Goyder and was first described in 1988. The species is a highly localized endemic found only in the Turkish province of Antalya. L. belinensis was listed among the top one hundred most endangered species of the world by the IUCN in 2012.

<i>Platanus rzedowskii</i> Species of tree

Platanus rzedowskii, commonly known as Rzedowski's plane tree, Rzedowski's sycamore, Sicómoro de la Sierra Madre Occidental, or the Sierra Madre Occidental sycamore, is a species of Platanus in the family Platanaceae. It was described by Jackie M. Poole in 2003 with the name attributed to Kevin C. Nixon.

References

  1. ↑ Synonymy - Platanus ×acerifolia. Northern Ontario Plant Database. Accessed online: 9 January 2011.
  2. ↑ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
  3. ↑ Selmi, Wissal; Weber, Christiane; Rivière, Emmanuel; Blonda, Nadège; Mehdi, Lotfi; Nowak, David. "Air pollution removal by trees in public green spaces in Strasbourg city, France" (PDF). Retrieved 20 April 2018.
  4. ↑ O. O. Wells, R. C. Schmidtling. "Sycamore" . Retrieved 23 December 2013.
  5. 1 2 Hull, R. (2009). "A Short Guide to the London Plane" (PDF). Retrieved 2 February 2016.
  6. ↑ Venables, B. (4 March 2015). "The Secret History Of The London Plane Tree". Londonist. Archived from the original on 2 February 2016. Retrieved 2 February 2016.
  7. 1 2 3 4 Bean. Trees and Shrubs Hardy in the British Isles. (8th ed., 1976)
  8. ↑ Interspecific Hybridization in Platanus. Author: Santamour, Frank S.1. Source: Forest Science, Volume 18, Number 3, 1 September 1972, pp. 236–239(4) Publisher: Society of American Foresters
  9. 1 2 Platanus acerifolia (Aiton) Willdenow. Flora of China, 9: 44. Accessed online: 9 January 2011.
  10. ↑ Aiton, W. 1789. Hortus Kewensis. 3: 364.
  11. ↑ Willdenow, C. L. 1805. Species Plantarum. Editio Quarta. Berolini. 4(1): 474.
  12. ↑ "Platanus × acerifolia". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens . Retrieved 9 January 2011.
  13. ↑ Definitions and Abbreviations of Terms used in the NOPD Checklist. Northern Ontario Plant Database. Accessed online: 9 January 2011.
  14. ↑ "Platanus hispanica auct". Germplasm Resources Information Network . Agricultural Research Service, United States Department of Agriculture . Retrieved 10 January 2011.
  15. ↑ "Fifty Great Trees for Fifty Great Years". The Tree Council. 2002. Archived from the original on 2003-01-06. Retrieved 1 May 2013.
  16. ↑ "RHS Plant Selector - Platanus × hispanica" . Retrieved 6 February 2021.
  17. ↑ "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 79. Retrieved 2 May 2018.
  18. ↑ "How to save Joburg's trees". Iol.co.za. Retrieved 25 November 2021.
  19. ↑ Lincoln, William A (1986). World Woods in Colour. Hertford UK: Stobard Davies Ltd. ISBN   0-85442-028-2.
  20. 1 2 3 4 Rushforth, K. (1999). Trees of Britain and Europe. HarperCollins ISBN   0-00-220013-9.
  21. ↑ Huxley, A., ed. (1992). New RHS Dictionary of Gardening. Macmillan.

Further reading

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