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{{Taxobox
| color = lightgreen
| name = ''Platanus''
| image = Plataan_bladeren.jpg
| image_width = 240px
| image_caption = Leaves and fruit of a London Plane
| regnum = [[Plant]]ae
| divisio = [[Flowering plant|Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Proteales]]
| familia = [[Platanaceae]]
| genus = '''''Platanus'''''
| subdivision_ranks = Species
| subdivision = See text
}}
:''"Plane tree" redirects here. In mathematics, "plane tree" refers to a [[tree (graph)|tree]] embedded in the [[plane (mathematics)|plane]].''
'''''Platanus''''' is a small genus of [[tree]]s native to the [[Northern Hemisphere]]. They are the sole members of the family '''[[Platanaceae]]'''.
They are all large trees to 30–50 m tall, [[deciduous]] (except for ''P. kerrii''), and are mostly found in [[riparian]] or other [[wetland]] [[habitat (ecology)|habitats]] in the wild, though proving [[drought]] tolerant in cultivation away from streams.
They are known as '''planes''' in Europe, and as '''sycamores''' in North America. (Outside North America, the name "[[sycamore]]" refers to either the [[fig]] ''[[Ficus sycomorus]]'', the plant originally so named, or the Great Maple, [[Acer pseudoplatanus]].)
==Natural history==
The flowers are reduced and are borne in balls (globose head); 3–7 hairy [[sepal]]s may be fused at base, and the petals are 3–7 (or no) and spathulate. Male and female flowers are separate, but on the same plant ([[monoecious]]). The number of heads in one cluster ([[inflorescence]]) is indicative of the species (see table below). The male flower has with 3–8 [[stamen]]s; the female has a superior ovary with 3–7 [[carpel]]s. Plane trees are wind-pollinated. Male balls fall off the branch after shedding their pollen. The female flowers, on the other hand, remain attached to the branch firmly.
[[Image:Platane, Trsteno.JPG|thumb|left|Bole of an aged ''Platanus'', in Trsteno, near [[Dubrovnik]], Croatia]]
After being pollinated, the female flowers become [[achene]]s that aggregate on the ball. Typically, the core of the ball is 1 cm in diameter and is covered with a net of mesh 1 mm, which can be peeled off. The ball is 2.5–4 cm in diameter and contains several hundred achenes, each of which has a single seed and is conical, with the point attached downward to the net at the surface of the ball. There is also a tuft of many thin stiff yellow-green bristle fibers attached to the base of each achene. These bristles help in wind dispersion of the fruits like [[dandelion]].
The mature bark peels (exfoliates) off easily in irregularly shaped patches, producing a mottled, scaly appearance. Very old bark may not flake off, but can crack instead. The base of the leaf stalk (petiole) is enlarged and completely wraps around the young stem bud in its axil. The bud will be exposed only after the leaf falls off.
==Phylogeny==
There are two subgenera, subgenus ''Castaneophyllum'' containing the anomalous ''P. kerrii'', and subgenus ''Platanus'', with all the others; recent studies in Mexico<ref>Nixon & Poole 2003</ref> have increased the number of accepted species in this subgenus. Within subgenus ''Platanus'', genetic evidence suggests that ''P. racemosa'' is more closely related to ''P. orientalis'' than it is to the other North American species.<ref>Feng et al. 2005</ref> There are fossil records of plane trees as early as 115 million years (the Lower Cretaceous). Despite the geographic separation between North America and Europe, species from these continents will cross readily resulting in fertile [[hybrid]]s such as the London Plane.
==Species==
The following are recognized species of plane trees:
{| class="wikitable"
! Scientific name !! Common name !! Distribution !! flowerheads !! Notes
|-
| ''[[Platanus chiapensis]]'' || Chiapas Plane || southeast [[Mexico]] || ? || Subgenus ''Platanus''
|-
| ''[[Platanus gentryi]]'' || Gentry's Plane || western [[Mexico]] || ? || Subgenus ''Platanus''
|-
| ''[[London Plane|Platanus × hispanica]]'' <br>(''P. occidentalis'' × ''P. orientalis''; <br>syn. ''P. × acerifolia'') || London Plane || Cultivated origin || 1-6 || Subgenus ''Platanus''
|-
| ''[[Platanus kerrii]]'' || Kerr's Plane || [[Laos]], [[Vietnam]] || 10-12 || Subgenus ''Castaneophyllum''
|-
| ''[[Platanus mexicana]]'' || Mexican Plane || northeast and central [[Mexico]] || 2-4 || Subgenus ''Platanus''
|-
| ''[[Platanus oaxacana]]'' || Oaxaca Plane || southern [[Mexico]] || ? || Subgenus ''Platanus''
|-
| ''[[Platanus occidentalis]]'' || American Sycamore, American Plane or Buttonwood || eastern [[North America]] || 1-2 || Subgenus ''Platanus''
|-
| ''[[Platanus orientalis]]'' || Oriental Plane || southeast [[Europe]], southwest [[Asia]] || 3-6 || Subgenus ''Platanus''
|-
| ''[[Platanus racemosa]]'' || California Sycamore || [[California]] || 3-7 || Subgenus ''Platanus''
|-
| ''[[Platanus rzedowskii]]'' || Rzedowski's Plane || eastern [[Mexico]] || ? || Subgenus ''Platanus''
|-
| ''[[Platanus wrightii]]'' || Arizona Sycamore || [[Arizona]], [[New Mexico]], northwest [[Mexico]] || 2-4 || Subgenus ''Platanus''
|-
|}
==Diseases==
[[Image:Platanus alley.jpg|thumb|right|250px||Avenue of plane trees]]
{{Main|List of sycamore diseases}}
Planes are susceptible to Plane Anthracnose ''Apiognomonia veneta'', a [[fungus|fungal]] [[disease]] that can defoliate the trees in some years. The worst infections are associated with cold, wet spring weather. ''P. occidentalis'' and the other American species are the most susceptible, with ''P. orientalis'' the most resistant. The hybrid London Plane is intermediate in resistance. Other diseases such as [[powdery mildew]] occur frequently, but are of lesser importance. ''Platanus'' species are used as food plants by the [[larva]]e of some [[Lepidoptera]] species including ''[[Phyllonorycter platani]]'' and [[Setaceous Hebrew Character]].
==Notes==
<references/>
== References==
*Feng, Y.; Oh, S.-H., & Manos, P. S. (2005). Phylogeny and Historical Biogeography of the Genus Platanus as Inferred From Nuclear and Chloroplast DNA. ''Syst. Bot.'' 30 (4): 786-799 [http://www.ingentaconnect.com/content/aspt/sb/2005/00000030/00000004/art00010;jsessionid=ku5cwifwjqxc.alice abstract]
*Nixon, K. C. & Poole, J. M. (2003). Revision of the Mexican and Guatemalan species of Platanus (Platanaceae). ''Lundellia'' 6: 103-137 [http://66.249.93.104/search?q=cache:n9IES08hSxYJ:vivo.library.cornell.edu/entity%3Fhome%3D1%26id%3D4558+platanus+rzedowskii&hl=en&ct=clnk&cd=14 abstract].
==External links==
*[http://www.aranya.co.uk/planes/text/botany.html Botany of Plane trees]
*[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10703 Flora of North America: ''Platanus'']
*[http://www.botgard.ucla.edu/html/MEMBGNewsletter/Volume5number2/Speakingtheplanetruth.html Photos with descriptions]
*''[http://www.amjbot.org/cgi/content/full/86/11/1523 A developmental and evolutionary analysis of embryology in Platanus (platanaceae), abasal eudicot]'', abstract of article by Sandra K. Floyd et al. in ''American Journal of Botany'', 1999;86:1523-1537.
[[Category:Proteales]]
[[Category:Plant families]]
[[Category:Trees of Chihuahua]]
| color = lightgreen
| name = ''Platanus''
| image = Plataan_bladeren.jpg
| image_width = 240px
| image_caption = Leaves and fruit of a London Plane
| regnum = [[Plant]]ae
| divisio = [[Flowering plant|Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Proteales]]
| familia = [[Platanaceae]]
| genus = '''''Platanus'''''
| subdivision_ranks = Species
| subdivision = See text
}}
:''"Plane tree" redirects here. In mathematics, "plane tree" refers to a [[tree (graph)|tree]] embedded in the [[plane (mathematics)|plane]].''
'''''Platanus''''' is a small genus of [[tree]]s native to the [[Northern Hemisphere]]. They are the sole members of the family '''[[Platanaceae]]'''.
They are all large trees to 30–50 m tall, [[deciduous]] (except for ''P. kerrii''), and are mostly found in [[riparian]] or other [[wetland]] [[habitat (ecology)|habitats]] in the wild, though proving [[drought]] tolerant in cultivation away from streams.
They are known as '''planes''' in Europe, and as '''sycamores''' in North America. (Outside North America, the name "[[sycamore]]" refers to either the [[fig]] ''[[Ficus sycomorus]]'', the plant originally so named, or the Great Maple, [[Acer pseudoplatanus]].)
==Natural history==
The flowers are reduced and are borne in balls (globose head); 3–7 hairy [[sepal]]s may be fused at base, and the petals are 3–7 (or no) and spathulate. Male and female flowers are separate, but on the same plant ([[monoecious]]). The number of heads in one cluster ([[inflorescence]]) is indicative of the species (see table below). The male flower has with 3–8 [[stamen]]s; the female has a superior ovary with 3–7 [[carpel]]s. Plane trees are wind-pollinated. Male balls fall off the branch after shedding their pollen. The female flowers, on the other hand, remain attached to the branch firmly.
[[Image:Platane, Trsteno.JPG|thumb|left|Bole of an aged ''Platanus'', in Trsteno, near [[Dubrovnik]], Croatia]]
After being pollinated, the female flowers become [[achene]]s that aggregate on the ball. Typically, the core of the ball is 1 cm in diameter and is covered with a net of mesh 1 mm, which can be peeled off. The ball is 2.5–4 cm in diameter and contains several hundred achenes, each of which has a single seed and is conical, with the point attached downward to the net at the surface of the ball. There is also a tuft of many thin stiff yellow-green bristle fibers attached to the base of each achene. These bristles help in wind dispersion of the fruits like [[dandelion]].
The mature bark peels (exfoliates) off easily in irregularly shaped patches, producing a mottled, scaly appearance. Very old bark may not flake off, but can crack instead. The base of the leaf stalk (petiole) is enlarged and completely wraps around the young stem bud in its axil. The bud will be exposed only after the leaf falls off.
==Phylogeny==
There are two subgenera, subgenus ''Castaneophyllum'' containing the anomalous ''P. kerrii'', and subgenus ''Platanus'', with all the others; recent studies in Mexico<ref>Nixon & Poole 2003</ref> have increased the number of accepted species in this subgenus. Within subgenus ''Platanus'', genetic evidence suggests that ''P. racemosa'' is more closely related to ''P. orientalis'' than it is to the other North American species.<ref>Feng et al. 2005</ref> There are fossil records of plane trees as early as 115 million years (the Lower Cretaceous). Despite the geographic separation between North America and Europe, species from these continents will cross readily resulting in fertile [[hybrid]]s such as the London Plane.
==Species==
The following are recognized species of plane trees:
{| class="wikitable"
! Scientific name !! Common name !! Distribution !! flowerheads !! Notes
|-
| ''[[Platanus chiapensis]]'' || Chiapas Plane || southeast [[Mexico]] || ? || Subgenus ''Platanus''
|-
| ''[[Platanus gentryi]]'' || Gentry's Plane || western [[Mexico]] || ? || Subgenus ''Platanus''
|-
| ''[[London Plane|Platanus × hispanica]]'' <br>(''P. occidentalis'' × ''P. orientalis''; <br>syn. ''P. × acerifolia'') || London Plane || Cultivated origin || 1-6 || Subgenus ''Platanus''
|-
| ''[[Platanus kerrii]]'' || Kerr's Plane || [[Laos]], [[Vietnam]] || 10-12 || Subgenus ''Castaneophyllum''
|-
| ''[[Platanus mexicana]]'' || Mexican Plane || northeast and central [[Mexico]] || 2-4 || Subgenus ''Platanus''
|-
| ''[[Platanus oaxacana]]'' || Oaxaca Plane || southern [[Mexico]] || ? || Subgenus ''Platanus''
|-
| ''[[Platanus occidentalis]]'' || American Sycamore, American Plane or Buttonwood || eastern [[North America]] || 1-2 || Subgenus ''Platanus''
|-
| ''[[Platanus orientalis]]'' || Oriental Plane || southeast [[Europe]], southwest [[Asia]] || 3-6 || Subgenus ''Platanus''
|-
| ''[[Platanus racemosa]]'' || California Sycamore || [[California]] || 3-7 || Subgenus ''Platanus''
|-
| ''[[Platanus rzedowskii]]'' || Rzedowski's Plane || eastern [[Mexico]] || ? || Subgenus ''Platanus''
|-
| ''[[Platanus wrightii]]'' || Arizona Sycamore || [[Arizona]], [[New Mexico]], northwest [[Mexico]] || 2-4 || Subgenus ''Platanus''
|-
|}
==Diseases==
[[Image:Platanus alley.jpg|thumb|right|250px||Avenue of plane trees]]
{{Main|List of sycamore diseases}}
Planes are susceptible to Plane Anthracnose ''Apiognomonia veneta'', a [[fungus|fungal]] [[disease]] that can defoliate the trees in some years. The worst infections are associated with cold, wet spring weather. ''P. occidentalis'' and the other American species are the most susceptible, with ''P. orientalis'' the most resistant. The hybrid London Plane is intermediate in resistance. Other diseases such as [[powdery mildew]] occur frequently, but are of lesser importance. ''Platanus'' species are used as food plants by the [[larva]]e of some [[Lepidoptera]] species including ''[[Phyllonorycter platani]]'' and [[Setaceous Hebrew Character]].
==Notes==
<references/>
== References==
*Feng, Y.; Oh, S.-H., & Manos, P. S. (2005). Phylogeny and Historical Biogeography of the Genus Platanus as Inferred From Nuclear and Chloroplast DNA. ''Syst. Bot.'' 30 (4): 786-799 [http://www.ingentaconnect.com/content/aspt/sb/2005/00000030/00000004/art00010;jsessionid=ku5cwifwjqxc.alice abstract]
*Nixon, K. C. & Poole, J. M. (2003). Revision of the Mexican and Guatemalan species of Platanus (Platanaceae). ''Lundellia'' 6: 103-137 [http://66.249.93.104/search?q=cache:n9IES08hSxYJ:vivo.library.cornell.edu/entity%3Fhome%3D1%26id%3D4558+platanus+rzedowskii&hl=en&ct=clnk&cd=14 abstract].
==External links==
*[http://www.aranya.co.uk/planes/text/botany.html Botany of Plane trees]
*[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10703 Flora of North America: ''Platanus'']
*[http://www.botgard.ucla.edu/html/MEMBGNewsletter/Volume5number2/Speakingtheplanetruth.html Photos with descriptions]
*''[http://www.amjbot.org/cgi/content/full/86/11/1523 A developmental and evolutionary analysis of embryology in Platanus (platanaceae), abasal eudicot]'', abstract of article by Sandra K. Floyd et al. in ''American Journal of Botany'', 1999;86:1523-1537.
[[Category:Proteales]]
[[Category:Plant families]]
[[Category:Trees of Chihuahua]]
