Editing Platanaceae

{{Short description|Family of flowering plants}}
{{Distinguish|Plantaginaceae}}
{{Use dmy dates|date=February 2014}}
{{Automatic taxobox
| fossil_range = {{fossil range|113|0|[[Albian]] - [[Holocene|recent]]|ref=<ref name=mobot>{{Cite web |title=Proteales |url=http://www.mobot.org/mobot/research/apweb/orders/protealesweb.html |access-date=2023-06-16 |website=www.mobot.org}}</ref>}}
| image = London plane flower.jpg
| image_caption = Inflorescence of ''[[Platanus × hispanica]]''
| taxon = Platanaceae
| authority = [[Thémistocle Gaspard Lestiboudois|T. Lestib.]]<ref name=APGIII2009>{{Cite journal |last=Angiosperm Phylogeny Group |year=2009 |title=An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III |journal=Botanical Journal of the Linnean Society |volume=161 |issue=2 |pages=105–121 |url=http://onlinelibrary.wiley.com/doi/10.1046/j.1095-8339.2003.t01-1-00158.x/pdf | format= PDF |access-date=2013-07-06 |doi=10.1111/j.1095-8339.2009.00996.x |doi-access=free |hdl=10654/18083 |hdl-access=free }}</ref>
| type_genus = ''[[Platanus]]'' {{small|[[Carl Linnaeus|L.]], 1753}}
| subdivision_ranks = Other genera
| subdivision = *†''[[Ambiplatanus]]'' {{small|(Mindell, Karafit & Stockey, 2014)}}
*†''[[Credneria]]'' {{small|Zenker, 1833}}
*†''[[Ettingshausenia]]'' {{small|([[August Wilhelm Stiehler|Stiehler]], 1857)}}
*†''[[Langeranthus]]'' {{small|Huegele & Manchester, 2022}}<ref name="Langeria2022">{{cite journal |last1=Huegele |first1=I. B. |last2=Manchester |first2=S. R. |year=2022 |title=Newly Recognized Reproductive Structures Linked with ''Langeria'' from the Eocene of Washington, USA, and their Affinities with Platanaceae |journal=International Journal of Plant Sciences |volume=In press |doi=10.1086/720138}}</ref>
*†''[[Langeria]]'' {{small|Wolfe & Wehr, 1987}}
*†''[[Macginicarpa]]'' {{small|Manchester, 1986}}
*†''[[Macginitiea]]'' {{small|[[Jack A. Wolfe|Wolfe]] & [[Wesley C. Wehr|Wehr]], 1987}}
*†''[[Plataninium]]'' {{small|(Unger, 1842)}}
*†''[[Platananthus]]'' {{small|Manchester, 1986}}
*†''[[Platimeliphyllum]]'' {{small|Maslova, 2002}}
*†''[[Pseudoprotophyllum]]'' {{small|Hollick, 1930}}
*†''[[Sapindopsis]]'' {{small|(Fontaine) Dilcher & Basson 1990}}
}}

'''Platanaceae''', the '''plane family''', is a [[family (biology)|family]] of flowering plants in the order [[Proteales]]. The family consists of only a single [[extant taxon|extant]] genus ''[[Platanus]]'', with twelve known species.<ref name="Christenhusz-Byng2016">{{cite journal |last1=Christenhusz |first1=M.J.M. |last2=Byng |first2=J.W. |name-list-style=amp |year=2016 |title=The number of known plants species in the world and its annual increase |journal=Phytotaxa |volume=261 |pages=201–217 |url=http://biotaxa.org/Phytotaxa/article/download/phytotaxa.261.3.1/20598 | doi = 10.11646/phytotaxa.261.3.1 |issue=3 |doi-access = free }}</ref> 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.

[[File:Macginitiea gracilis SRIC SR 01-03-04 A img1.jpg|thumb|right|49-million-year-old fossil ''[[Macginitiea|Macginitiea gracilis]]'' from the [[Klondike Mountain Formation]], [[Washington (state)|Washington]]]]

== Description ==
[[File:Platanus orientalis tree, Thasos.jpg|thumb|left| Example of ''P. orientalis'']]
* Large, sympodial, deciduous [[tree]], speckled [[bark (botany)|bark]] that sheds in large irregular sheets, leaving a smooth surface that is mottled and pale, persistent bark at the base of the trunk, indumentum with large glandular hairs, multicellular and uniserrate or short with uniserrate ramification (in candelabrum), in stellate fascicles; glandular hairs with unicellular, globular capitulum, cuticular [[wax]]es without crystalloids, with rods and plates
* [[Leaf|Leaves]] generally with very variable shapes and nervation, simple, alternate, more or less distichous, isobilateral palmate with three to seven lobes (palmatifid to palmatisect) with whole edges or with glandular teeth (each one with a midvein that broadens towards the glandular apex, where it ends in an open hole), or penninerved and whole (''[[Platanus kerrii]]''), this shape common in young, vernal leaves in other species, [[vernation]] folded, with the [[Petiole (botany)|petiole]] usually sheathed, enclosing the axillary bud (bud is free in ''P. kerrii''), [[stipule]]s foliose, large, intrapetiolar, tubular, normally caduceus, in ''P. kerrii'' scarious, small, basally fused to the petiole, [[Domatium|domatia]] present, [[stoma]]ta irregularly anomocytic
* [[Plant stem|Stem]]s with aggregated rays in the xylem, with nodes septilacunar, [[cork cambium]] present and superficial, [[bud]]s covered by single scale
* [[Plant]]s monoecious, the flowers of each sex in separate inflorescences
* [[Inflorescence]]s <!-- 1-7(-12) --> in large hanging peduncles, each one a unisexual, globular [[pseudanthium|capitulum]], pedunculate or seated, with numerous flowers, derived from the condensation of a panicle, with a circular [[bract]] at the base and [[bracteole]]s among the flowers
* [[Flower]]s small, inconspicuous, hypogynous, regular unisexual, [[Receptacle (botany)|receptacle]] short, smooth, hypogynous disk absent, [[perianth]] reduced, [[sepal]]s  number three to four, rarely eight, free or basally fused, shorter than the petals, triangular. [[Petal]]s number three to four, rarely eight, truncated-spatulate or vestigial, scarious, frequently absent in the female flowers, male flowers with androecium haplostemonous, isostemonous, oppositisepal, with number three to four, rarely eight, [[stamen]]s, [[Column (botany)|gynostemium]] short or vestigial, [[anther]]s basifixed, not versatile, dithecous, tetrasporangiate, elongated, connectivum apically widened, peltate, [[Dehiscence (botany)|dehiscence]] along longitudinal valves; pistillidium sometimes present, female flowers with superior gynoecium <!-- of (3-)5-8(-9) --> [[carpel]]s apocarpous in two or three [[Whorl (botany)|whorl]]s, imperfectly closed apically, surrounded by large petals, linear stylodious, [[Stigma (botany)|stigmas]] internal, decurrent in two ridges, more or less dry, two [[ovule]]s per carpel but one nearly always aborts, orthotropous, bitegmic, crassinucellated, pendulous, apical to marginal [[placentation]],  three or four [[staminode]]s 3-4, no nectaries
* [[Fruit]] in an [[achene]], clavate, grouped in a globular capituliform [[infructescence]], each fruit surrounded by long hairs

<gallery>
Image:Platanus orientalis fruit body 01.jpg|Fruiting body of ''P. orientalis'' (Oriental plane).
Image:American sycamore (Platanus occidentalis) 2.jpg|Fruiting body of ''P. occidentalis'' (American sycamore) with some achenes removed
Image:Platanus nucula 01.JPG|An achene
Image:Fruit morphology fruit type - achene (from multiple fruit of achenes Platanus).svg|Cross section of an achene with the seed shown in brown
</gallery>

* [[Seed]]s are small with thin [[Testa (botany)|testa]] with little [[endosperm]], oily and proteinaceous, [[embryo]] thin and straight with two linear cotyledons, often uneven 
* [[Pollen]] in subprolate monads, 16-22 μm in length, tricolpate, sometimes sextarugate, tectate-columellate, reticulated surface, the base layer as thick as the tectum
* [[Chromosome|Chromosomal number]]: ''2n'' = 14, 16, 21, 42; ''x'' probably equal to 7 or 8

== Ecology ==
[[Pollination]] is [[Anemophily|anemophilous]]; flowering begins at the start of spring when the new leaves are sprouting. The heads that sustain the fruit normally shed the year after they have matured, during the autumn. [[Seed dispersal|Dispersion]] of the individual fruiting bodies, with their thistledown, is anemochorous (they are sometimes dispersed by water as a secondary mechanism).

The plants grow in cool situations in temperate climates and are frequently found on the banks of rivers and streams. They are totally absent from dry or excessively cold areas.

== Phytochemistry ==
They contain [[cyanogenic glycosides]] derived from [[tyrosine]], [[flavonoid]]s belonging to the [[Condensed tannin|proanthocyanidins]] group (e.g. [[prodelphinidin]]) and [[flavonol]]s ([[kaempferol]], [[quercetin]], [[myricetin]]), in addition to [[Triterpenoid|triterpenol]]s (including [[betulinic acid]]). They lack [[ellagic acid]], [[saponin]]s, and [[sapogenin]]s.

== Cultivation ==
[[File:Platanus occidentalis GS344.png|thumb|Morphological details of ''P. occidentalis'']]
The main use for a number of the species is to provide shade in pedestrian areas in temperate regions, particularly the London plane (''[[Platanus × hispanica]]''), which is widely distributed throughout Europe and North America. It is highly resistant, probably due to so-called [[hybrid vigour]], although its use requires caution due to their allergy-producing thistledown. The parent species are also grown for the same effect, but with poorer results as they are less resistant to contamination, among other reasons. The wood is used in cabinetmaking, paneling, and other interior work, and is also prized for its long burn time.

== Fossils ==
A large number of fossils of this family have been recorded from the Lower [[Cretaceous]] (98-113 million years ago, ''Platanocarpus''). The examples from that time had very small pollen (8-10 μm) and a developed perianth and they lacked hairs at the base of the nucule.  It is thought to have had [[Entomophily|entomophilous]] pollination. During the mid Cretaceous, the fossilized forms with platanoid leaves became mixed with pinnate leaves (''Sapindopsis'') or pedatisect leaves (''Debeya'', ''Dewalquea''), and these forms lasted until the [[Eocene]]. The leaves with typical stipules belonging to the sub-genus ''Platanus'' are very common in [[Palaeocene]] formations (60 M years ago). It is thought that the only modern genus, ''Platanus'', is a [[Relict (biology)|relict]] that can be considered a [[living fossil]]. It must have been [[polyploid]] during its evolution judging by the size of its stomata.

== Systematic position ==
The [[APG II system]] (2003) allows the option of including it in the family [[Proteaceae]], or treating it as distinct as a segregate family. In as far as APG II accepts the family, it is placed in the order [[Proteales]], in the clade [[eudicots]]. This represents a slight change from the [[APG system]] of 1998, which did accept this family.  The [[Cronquist system]] of 1981 recognized the family and placed it in order [[Hamamelidales]], in subclass [[Hamamelidae]] {{sic}} in class [[Magnoliopsida]] (dicotyledons). The [[Dahlgren system]] and [[Thorne system (1992)]] also recognized this family and placed it in the order Hamamelidales in superorder Rosanae in subclass Magnoliidae ''sensu'' Dahlgren and Thorne (dicotyledons). The [[Engler system]], in its 1964 update, also recognized the family and placed it in the order [[Rosales]] in subclass Archichlamydeae of class [[Dicotyledoneae]]. The [[Wettstein system]], last revised in 1935, also recognized the family and placed it in the order Hamamelidales in the Monochlamydeae in subclass Choripetalae of the class Dicotyledones. Based on molecular and morphological data the APW (Angiosperm Phylogeny Website) places the family in the order Proteales as a sister family to the [[Proteaceae]], making them the Northern Hemisphere version of this family (cf.  [http://www.mobot.org/MOBOT/Research/APweb/welcome.html AP-website]).

== Taxa included ==
:''Theoretical introduction to [[Taxonomy (biology)|Taxonomy]]''

The only extant genus, ''Platanus'' [[Carl Linnaeus|L.]], 1753, has the type species ''[[Platanus orientalis]]'' [[Carl Linnaeus|L.]], 1753. It is divided into two subgenera: the subgenus ''Castaneophyllum'' [[Jean-François Leroy|J.-F. Leroy]], 1982, with elliptical, penninerved leaves with small scarious, stipules, that only includes ''[[Platanus kerrii]]'' [[François Gagnepain|Gagnep.]], 1939, an isolated relict species that represents the genus’ evolutionary basal branch and which is the sister group of the other species, which comprise the subgenus ''Platanus''.

== Hybrids ==
[[File:Platanus orientalis bark on trunk 02.jpg|thumb|left|Bark of ''P. orientalis'']]
The London plane or hybrid plane has long been considered a hybrid derived from the cross between ''P. occidentalis'' and ''P. orientalis'', despite this its origin is not clear. Some experts think it originated in London and others in Spain or even in natural or cultivated hybrid form (or not) in Turkey. The question has not been investigated with modern molecular methods. As a consequence, even its nomenclature is hotly debated, to the extent that until recently, some anglophone authors denied the priority of the name used by [[Otto von Münchhausen]] (following Maria da Luz de Oliveira Tavares Monteiro da Rocha Afonso, 1990, see References). The plant is not found in the wild, though it appears in a [[naturalisation (biology)|naturalised]] form along the banks of rivers and streams.

Hybrid ''[[Platanus × hispanica]]'' <small> [[Philip Miller|Mill.]] ex [[Otto von Münchhausen|Münchh.]], 1770</small> (= ''P. orientalis'' var. ''acerifolia'' <small>[[William Aiton|Aiton]], 1789</small>; ''P. hybrida'' <small>[[Félix de Avelar Brotero|Brot.]], 1804</small>; ''P. vulgaris'' <small>[[Édouard Spach|Spach]], 1841, ''nom. illeg.''</small>; ''P. × acerifolia''.

Other names proposed for hybrids that are probably synonymous with the above, which is the only name in English, and which represent smaller minorities are:
* Hybrid ''Platanus'' × ''cantabrigensis'' <small>[[A.Henry]], 1919</small>
* Hybrid ''Platanus'' × ''parviloba'' <small>[[Augustine Henry|A.Henry]], 1919</small>

The references consulted do not agree as to whether the fruit is a nucule or [[achene]], the difference between the two ultimately depends on the size of the pericarp and the extent of its lignification. The fruit is dry, indehiscent, monocarpelar and monospermatic.

== References ==
{{Reflist}}
* {{cite book
| author = Kubitzki, K.
| chapter = Platanaceae.
| title = Kubitzki, K., Rohwer, J.G. & Bittrich, V. (Editores). The Families and Genera of Vascular Plants. II. Flowering Plants - Dicotyledons. 
| year = 1993
| publisher = Springer-Verlag: Berlín
| isbn = 978-3-540-55509-4
}}
* {{cite book
| author = Rocha Afonso, M.L.
| chapter = Platanus
| title = S. Castroviejo ''et al.''(Editores). Flora Iberica Vol. II 
| year = 1990
| publisher = C.S.I.C.
| isbn = 978-84-00-07034-2
}}
* {{Cite web
|author1= Watson, L.
|author2= Dallwitz, M.J.
|name-list-style= amp
|title= The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 29th July 2006.
|date= 1992
|url= http://delta-intkey.com
|access-date= 31 January 2007
|archive-date= 3 January 2007
|archive-url= https://web.archive.org/web/20070103200438/http://delta-intkey.com/
|url-status= dead
}}

== External links ==
* {{Commons category-inline|Platanaceae}}
* {{Wikispecies-inline}}
* [http://delta-intkey.com/angio/www/platanac.htm Platanaceae] in L. Watson and M.J. Dallwitz (1992 onwards), [http://delta-intkey.com/angio/ The families of flowering plants] {{Webarchive|url=https://web.archive.org/web/20070103200438/http://delta-intkey.com/ |date=3 January 2007 }}.
* [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10703 ''Flora of North America'': Platanaceae]
* [http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=10703 ''Flora of China'': Platanaceae]
* [https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=4401&lvl=3&p=mapview&p=has_linkout&p=blast_url&p=genome_blast&lin=f&keep=1&srchmode=1&unlock NCBI Taxonomy Browser]
* [http://www.csdl.tamu.edu/FLORA/cgi/gateway_family?fam=Platanaceae links at CSDL] {{Webarchive|url=https://web.archive.org/web/20081013055926/http://www.csdl.tamu.edu/FLORA/cgi/gateway_family?fam=Platanaceae |date=13 October 2008 }}
* [http://www.mobot.org/MOBOT/Research/APweb/maps/platanaceae.gif Map, incomplete for Asia]
* [https://web.archive.org/web/20110806045020/http://www.csupomona.edu/~jcclark/flora/plants/platanaceae/platanus_racemosa_lf.jpg Foliage of ''Platanus racemosa'']
* [http://academic.evergreen.edu/l/leroyc/photo/platanus.png ''Platanus wrightii''] {{Webarchive|url=https://web.archive.org/web/20120219091758/http://academic.evergreen.edu/l/leroyc/photo/platanus.png |date=19 February 2012 }}
* [http://texastreeplanting.tamu.edu/treepictures/sycamore_mex.jpg Drawing of ''Platanus mexicana'']
* [http://132.236.163.186/users/kcn2/toupload71/Platanus_rzedowskii1.jpg Female inflorescence of ''Platanus rzedowskii'']{{Dead link|date=May 2020 |bot=InternetArchiveBot |fix-attempted=yes }}

{{Angiosperm families}}
{{Taxonbar|from=Q171425}}
{{Authority control}}

[[Category:Platanaceae| ]]
[[Category:Eudicot families]]
[[Category:Extant Cretaceous first appearances]]