Kpdhage at 12:22, 16 September 2009

2009-09-16T12:22:32Z

Envoy at 15:32, 4 November 2007

2007-11-04T15:32:25Z

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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]]

← Older revision		Revision as of 12:22, 16 September 2009
Line 1:		Line 1:
		+	{{Inc\|
		+	Platanus (its ancient Greek name). Platanaceae. Plane-tree. Buttonwood. Ornamental 'trees with handsome dense foliage, often planted as shade and street trees.
		+
		+	Deciduous, with the bark exfoliating in thin plates, but at the base of older trunks the bark is persistent, of darker color and furrowed: stipules conspicuous, usually connate into a tube, with spreading lf.-like margin; petiole with the enlarged base inclosing the axillary bud: lvs. palmately lobed, covered densely with stellate hairs when young: fls. monoecious, in dense globular heads, staminate and pistillate similar, but on separate peduncles; sepals and petals 3-8; staminate with 3-8 stamens, pistillate with 3-8 pistils with elongated styles: fr.-heads consisting of numerous narrowly obconical, 1-seeded nutlets surrounded at the base by long hairs.—Six or 7 species are known in N. Amer., south to Mex. and from S. E. Eu. to India.
		+
		+	The planes are handsome trees with large and palmately lobed leaves and small greenish flowers in drooping heads, followed by similar heads of fruits remaining on the branches during the winter. The smooth light-colored often almost creamy white bark of the branches and limbs, usually mottled by darker blotches of the older bark, which peels off in large thin plates, gives the tree a very characteristic appearance in winter, while in summer the plane-tree, with its large head of dense bright green foliage and with its massive trunk is a beautiful and majestic shade tree. The native P. occidentalis is hardy North and P. aceri- folia and P. orientalis hardy as far north as Massachusetts, while the southwestern and Mexican species cannot be cultivated in the North. From time immemorial, the oriental plane, which was well known to the ancient Greek writers, has been famous for the large size it attains—trunks of 30 feet in diameter and more are reported to exist—and has been planted as a shade tree in western Asia and southern Europe, and today it is still one of the favorite street trees throughout the temperate regions of Europe. It has also been recognized in this country as one of the best street trees, even to be preferred to the native plane, which, unfortunately, suffers from the attacks of a fungus, Gloeo- sporium nervisequum, while the oriental is not injured by it. The plane-trees stand pruning—even severe pruning—well. To what extent they are sometimes pruned in European cities without losing their vitality is shown in an interesting illustration in "Forest Leaves," Vol. III, p. 97. They are also easily transplanted even as larger trees. They grow best in a deep and rich moist soil. Propagation is by seeds sown in spring and only slightly covered with soil and kept moist and shaded; also by cuttings of ripened wood and by greenwood cuttings under glass in June taken with a heel, and sometimes by layers. Varieties are also sometimes grafted in spring on seedlings of one of the species. The stellate hairs of the young leaves when detached by the wind, sometimes float in great quantities in the air and are liable to cause irritation and sometimes inflammation of the mucous membranes of the eye, nose, and mouth. But as this is likely to occur only during a very limited period late in spring it can hardly be considered as a serious objection to the use of platanus as a street tree.
		+	P. vulgaris, Spach, comprises all species of the genus.—P. Wrightii. Wats. Tree, to 80 ft., often divided into several sts.: lvs. usually cordate or truncate, deeply 3-7-lobed, with lanceolate, acuminate, entire or dentate lobes, tomentose beneath or nearly glabrous at length, 6-8 in. long: fr.-heads racemose, rather smooth, each on a short stalk. New Mex. and Aris. to Calif. S.S. 7:329.
		+	The other species, as P. mexicana, Moric., which is sometimes planted as a street tree in Mex., P. Lindeniana, Mart. & Gal., and P. glabrata. Fern., all natives of Mex., are not yet intro.
		+	Alfred Rehder.
		+	}}
		+
		+
	{{Taxobox		{{Taxobox
	\| color = lightgreen		\| color = lightgreen

Platanus - Revision history

Kpdhage at 12:22, 16 September 2009

Envoy at 15:32, 4 November 2007