Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Platanaceae
open-in-new
<h2 id="description">Description</h2> <ul><li>Large, sympodial, deciduous <a href="/facts/Tree/HVVn3srN">tree</a>, speckled <a href="/facts/Bark_(botany)/vdL49ec1">bark</a> 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 <a href="/facts/Wax/MAXhjzNh">waxes</a> without crystalloids, with rods and plates</li> <li><a href="/facts/Leaf/1m6wCNTg">Leaves</a> 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 (<i><a href="/facts/Platanus_kerrii/AgcXR0Fj">Platanus kerrii</a></i>), this shape common in young, vernal leaves in other species, <a href="/facts/Vernation/tpd4NQvz">vernation</a> folded, with the <a href="/facts/Petiole_(botany)/pext65Wr">petiole</a> usually sheathed, enclosing the axillary bud (bud is free in <i>P. kerrii</i>), <a href="/facts/Stipule/dpF27NFo">stipules</a> foliose, large, intrapetiolar, tubular, normally caduceus, in <i>P. kerrii</i> scarious, small, basally fused to the petiole, <a href="/facts/Domatium/Dc2Y61Fa">domatia</a> present, <a href="/facts/Stoma/Rer9Nzct">stomata</a> irregularly anomocytic</li> <li><a href="/facts/Plant_stem/QlQWSzV4">Stems</a> with aggregated rays in the xylem, with nodes septilacunar, <a href="/facts/Cork_cambium/7MvQF7ss">cork cambium</a> present and superficial, <a href="/facts/Bud/USYHoQv8">buds</a> covered by single scale</li> <li><a href="/facts/Plant/X5BMDMvS">Plants</a> monoecious, the flowers of each sex in separate inflorescences</li> <li><a href="/facts/Inflorescence/CvpNd4vS">Inflorescences</a> in large hanging peduncles, each one a unisexual, globular <a href="/facts/Pseudanthium/ANBv3Iym">capitulum</a>, pedunculate or seated, with numerous flowers, derived from the condensation of a panicle, with a circular <a href="/facts/Bract/pnMGNMdn">bract</a> at the base and <a href="/facts/Bracteole/pnMGNMdn">bracteoles</a> among the flowers</li> <li><a href="/facts/Flower/7gI5Kefw">Flowers</a> small, inconspicuous, hypogynous, regular unisexual, <a href="/facts/Receptacle_(botany)/sUVrrdwS">receptacle</a> short, smooth, hypogynous disk absent, <a href="/facts/Perianth/dy8xGxeb">perianth</a> reduced, <a href="/facts/Sepal/rFYnXN4d">sepals</a> number three to four, rarely eight, free or basally fused, shorter than the petals, triangular. <a href="/facts/Petal/DQMkpRSm">Petals</a> 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, <a href="/facts/Stamen/MzNPVK3D">stamens</a>, <a href="/facts/Column_(botany)/t3TTW9na">gynostemium</a> short or vestigial, <a href="/facts/Anther/MzNPVK3D">anthers</a> basifixed, not versatile, dithecous, tetrasporangiate, elongated, connectivum apically widened, peltate, <a href="/facts/Dehiscence_(botany)/w5cbltMG">dehiscence</a> along longitudinal valves; pistillidium sometimes present, female flowers with superior gynoecium <a href="/facts/Carpel/P5qFQMk1">carpels</a> apocarpous in two or three <a href="/facts/Whorl_(botany)/dhD4zdUI">whorls</a>, imperfectly closed apically, surrounded by large petals, linear stylodious, <a href="/facts/Stigma_(botany)/JEQ85ChP">stigmas</a> internal, decurrent in two ridges, more or less dry, two <a href="/facts/Ovule/DFvS1VvA">ovules</a> per carpel but one nearly always aborts, orthotropous, bitegmic, crassinucellated, pendulous, apical to marginal <a href="/facts/Placentation/nqcxcaPM">placentation</a>, three or four <a href="/facts/Staminode/44XDV0IQ">staminodes</a> 3-4, no nectaries</li> <li><a href="/facts/Fruit/PBpuzk60">Fruit</a> in an <a href="/facts/Achene/8dm9UxMy">achene</a>, clavate, grouped in a globular capituliform <a href="/facts/Infructescence/DvKfhqCa">infructescence</a>, each fruit surrounded by long hairs</li></ul> <ul><li><a href="/facts/Seed/a4xGSLxJ">Seeds</a> are small with thin <a href="/facts/Testa_(botany)/a4xGSLxJ">testa</a> with little <a href="/facts/Endosperm/oGnmuWud">endosperm</a>, oily and proteinaceous, <a href="/facts/Embryo/9QHnLVLN">embryo</a> thin and straight with two linear cotyledons, often uneven</li> <li><a href="/facts/Pollen/eqRP052I">Pollen</a> in subprolate monads, 16-22 μm in length, tricolpate, sometimes sextarugate, tectate-columellate, reticulated surface, the base layer as thick as the tectum</li> <li><a href="/facts/Chromosome/FRGf11FC">Chromosomal number</a>: <i>2n</i> = 14, 16, 21, 42; <i>x</i> probably equal to 7 or 8</li></ul> <h2 id="ecology">Ecology</h2> <p><a href="/facts/Pollination/u383g7XJ">Pollination</a> is <a href="/facts/Anemophily/37MXM06c">anemophilous</a>; 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. <a href="/facts/Seed_dispersal/yNofEeyA">Dispersion</a> of the individual fruiting bodies, with their thistledown, is anemochorous (they are sometimes dispersed by water as a secondary mechanism). </p><p>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. </p> <h2 id="phytochemistry">Phytochemistry</h2> <p>They contain <a href="/facts/Cyanogenic_glycosides/z11RwaaB">cyanogenic glycosides</a> derived from <a href="/facts/Tyrosine/RJhEgE4C">tyrosine</a>, <a href="/facts/Flavonoid/J7FEAtLE">flavonoids</a> belonging to the <a href="/facts/Condensed_tannin/t4sPgWPw">proanthocyanidins</a> group (e.g. <a href="/facts/Prodelphinidin/FKQkzutT">prodelphinidin</a>) and <a href="/facts/Flavonol/cFmUlN8u">flavonols</a> (<a href="/facts/Kaempferol/mLleEu8u">kaempferol</a>, <a href="/facts/Quercetin/Ed1BP1YD">quercetin</a>, <a href="/facts/Myricetin/HrE6o1Ns">myricetin</a>), in addition to <a href="/facts/Triterpenoid/IaToe1HU">triterpenols</a> (including <a href="/facts/Betulinic_acid/SLTWPbIT">betulinic acid</a>). They lack <a href="/facts/Ellagic_acid/fVTXDHbP">ellagic acid</a>, <a href="/facts/Saponin/0cqUdnJM">saponins</a>, and <a href="/facts/Sapogenin/UyY4Rojl">sapogenins</a>. </p> <h2 id="cultivation">Cultivation</h2> <p>The main use for a number of the species is to provide shade in pedestrian areas in temperate regions, particularly the London plane (<i><a href="/facts/Platanus_%25C3%2597_hispanica/lTTYVxJM">Platanus × hispanica</a></i>), which is widely distributed throughout Europe and North America. It is highly resistant, probably due to so-called <a href="/facts/Hybrid_vigour/hyvtkDE8">hybrid vigour</a>, 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. </p> <h2 id="fossils">Fossils</h2> <p>A large number of fossils of this family have been recorded from the Lower <a href="/facts/Cretaceous/nwKtFtKx">Cretaceous</a> (98-113 million years ago, <i>Platanocarpus</i>). 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 <a href="/facts/Entomophily/cSwptQsL">entomophilous</a> pollination. During the mid Cretaceous, the fossilized forms with platanoid leaves became mixed with pinnate leaves (<i>Sapindopsis</i>) or pedatisect leaves (<i>Debeya</i>, <i>Dewalquea</i>), and these forms lasted until the <a href="/facts/Eocene/EYgI8Uco">Eocene</a>. The leaves with typical stipules belonging to the sub-genus <i>Platanus</i> are very common in <a href="/facts/Palaeocene/IWWoh8D9">Palaeocene</a> formations (60 M years ago). It is thought that the only modern genus, <i>Platanus</i>, is a <a href="/facts/Relict_(biology)/eH1gkAg3">relict</a> that can be considered a <a href="/facts/Living_fossil/EujFvU2D">living fossil</a>. It must have been <a href="/facts/Polyploid/L7xyKHdK">polyploid</a> during its evolution judging by the size of its stomata. </p> <h2 id="systematic-position">Systematic position</h2> <p>The <a href="/facts/APG_II_system/hxewkKQy">APG II system</a> (2003) allows the option of including it in the family <a href="/facts/Proteaceae/0kaj3LaH">Proteaceae</a>, or treating it as distinct as a segregate family. In as far as APG II accepts the family, it is placed in the order <a href="/facts/Proteales/llqfvuY3">Proteales</a>, in the clade <a href="/facts/Eudicots/exlS0I93">eudicots</a>. This represents a slight change from the <a href="/facts/APG_system/8fLMu2zs">APG system</a> of 1998, which did accept this family. The <a href="/facts/Cronquist_system/XHFWQ4dQ">Cronquist system</a> of 1981 recognized the family and placed it in order <a href="/facts/Hamamelidales/GLPza2VB">Hamamelidales</a>, in subclass <a href="/facts/Hamamelidae/Ayz7X9uX">Hamamelidae</a> [<i><a href="/facts/Sic/qB9MUUWF">sic</a></i>] in class <a href="/facts/Magnoliopsida/zyprXsUD">Magnoliopsida</a> (dicotyledons). The <a href="/facts/Dahlgren_system/bdvgygmR">Dahlgren system</a> and <a href="/facts/Thorne_system_(1992)/o9MQ8E9X">Thorne system (1992)</a> also recognized this family and placed it in the order Hamamelidales in superorder Rosanae in subclass Magnoliidae <i>sensu</i> Dahlgren and Thorne (dicotyledons). The <a href="/facts/Engler_system/fDl8NEut">Engler system</a>, in its 1964 update, also recognized the family and placed it in the order <a href="/facts/Rosales/H73YkSeg">Rosales</a> in subclass Archichlamydeae of class <a href="/facts/Dicotyledoneae/yat51Ncq">Dicotyledoneae</a>. The <a href="/facts/Wettstein_system/Dt4vyx86">Wettstein system</a>, 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 <a href="/facts/Proteaceae/0kaj3LaH">Proteaceae</a>, making them the Northern Hemisphere version of this family (cf. <a href="http://www.mobot.org/MOBOT/Research/APweb/welcome.html">AP-website</a>). </p> <h2 id="taxa-included">Taxa included</h2> <i>Theoretical introduction to <a href="/facts/Taxonomy_(biology)/Qkg8wuyw">Taxonomy</a></i> <p>The only extant genus, <i>Platanus</i> <a href="/facts/Carl_Linnaeus/gy5HWkHS">L.</a>, 1753, has the type species <i><a href="/facts/Platanus_orientalis/R18Uh5IQ">Platanus orientalis</a></i> <a href="/facts/Carl_Linnaeus/gy5HWkHS">L.</a>, 1753. It is divided into two subgenera: the subgenus <i>Castaneophyllum</i> <a href="/facts/Jean-Fran%25C3%25A7ois_Leroy/E7Gwlyqd">J.-F. Leroy</a>, 1982, with elliptical, penninerved leaves with small scarious, stipules, that only includes <i><a href="/facts/Platanus_kerrii/AgcXR0Fj">Platanus kerrii</a></i> <a href="/facts/Fran%25C3%25A7ois_Gagnepain/aAsj4xBz">Gagnep.</a>, 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 <i>Platanus</i>. </p> <h2 id="hybrids">Hybrids</h2> <p>The London plane or hybrid plane has long been considered a hybrid derived from the cross between <i>P. occidentalis</i> and <i>P. orientalis</i>, 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 <a href="/facts/Otto_von_M%25C3%25BCnchhausen/BnGAtmmF">Otto von Münchhausen</a> (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 <a href="/facts/Naturalisation_(biology)/6lc476BI">naturalised</a> form along the banks of rivers and streams. </p><p>Hybrid <i><a href="/facts/Platanus_%25C3%2597_hispanica/lTTYVxJM">Platanus × hispanica</a></i> <a href="/facts/Philip_Miller/09PlMzwa">Mill.</a> ex <a href="/facts/Otto_von_M%25C3%25BCnchhausen/BnGAtmmF">Münchh.</a>, 1770 (= <i>P. orientalis</i> var. <i>acerifolia</i> <a href="/facts/William_Aiton/rso2gHs8">Aiton</a>, 1789; <i>P. hybrida</i> <a href="/facts/F%25C3%25A9lix_de_Avelar_Brotero/TXjBmLEl">Brot.</a>, 1804; <i>P. vulgaris</i> <a href="/facts/%25C3%2589douard_Spach/gtSdWCu5">Spach</a>, 1841, <i>nom. illeg.</i>; <i>P. × acerifolia</i>. </p><p>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: </p> <ul><li>Hybrid <i>Platanus</i> × <i>cantabrigensis</i> <a href="/facts/A.Henry/qJdJyFto">A.Henry</a>, 1919</li> <li>Hybrid <i>Platanus</i> × <i>parviloba</i> <a href="/facts/Augustine_Henry/qJdJyFto">A.Henry</a>, 1919</li></ul> <p>The references consulted do not agree as to whether the fruit is a nucule or <a href="/facts/Achene/8dm9UxMy">achene</a>, 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. </p> <ul><li>Kubitzki, K. (1993). "Platanaceae.". <i>Kubitzki, K., Rohwer, J.G. & Bittrich, V. (Editores). The Families and Genera of Vascular Plants. II. Flowering Plants - Dicotyledons</i>. Springer-Verlag: Berlín. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-3-540-55509-4.</li> <li>Rocha Afonso, M.L. (1990). "Platanus". <i>S. Castroviejo </i>et al.<i>(Editores). Flora Iberica Vol. II</i>. C.S.I.C. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-84-00-07034-2.</li> <li>Watson, L. & Dallwitz, M.J. (1992). <a href="https://web.archive.org/web/20070103200438/http://delta-intkey.com/">"The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 29th July 2006"</a>. Archived from <a href="http://delta-intkey.com">the original</a> on 3 January 2007. Retrieved 31 January 2007.</li></ul> <h2 id="external-links">External links</h2> <ul><li> Media related to Platanaceae at Wikimedia Commons</li> <li> Data related to Platanaceae at Wikispecies</li> <li><a href="http://delta-intkey.com/angio/www/platanac.htm">Platanaceae</a> in L. Watson and M.J. Dallwitz (1992 onwards), <a href="http://delta-intkey.com/angio/">The families of flowering plants</a> <a href="https://web.archive.org/web/20070103200438/http://delta-intkey.com/">Archived</a> 3 January 2007 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a>.</li> <li><a href="http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10703"><i>Flora of North America</i>: Platanaceae</a></li> <li><a href="http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=10703"><i>Flora of China</i>: Platanaceae</a></li> <li><a href="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</a></li> <li><a href="http://www.csdl.tamu.edu/FLORA/cgi/gateway_family?fam=Platanaceae">links at CSDL</a> <a href="https://web.archive.org/web/20081013055926/http://www.csdl.tamu.edu/FLORA/cgi/gateway_family?fam=Platanaceae">Archived</a> 13 October 2008 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li> <li><a href="http://www.mobot.org/MOBOT/Research/APweb/maps/platanaceae.gif">Map, incomplete for Asia</a></li> <li><a href="https://web.archive.org/web/20110806045020/http://www.csupomona.edu/~jcclark/flora/plants/platanaceae/platanus_racemosa_lf.jpg">Foliage of <i>Platanus racemosa</i></a></li> <li><a href="http://academic.evergreen.edu/l/leroyc/photo/platanus.png"><i>Platanus wrightii</i></a> <a href="https://web.archive.org/web/20120219091758/http://academic.evergreen.edu/l/leroyc/photo/platanus.png">Archived</a> 19 February 2012 at the <a href="/facts/Wayback_Machine/nmQ3a6JC">Wayback Machine</a></li> <li><a href="http://texastreeplanting.tamu.edu/treepictures/sycamore_mex.jpg">Drawing of <i>Platanus mexicana</i></a></li> <li><a href="http://132.236.163.186/users/kcn2/toupload71/Platanus_rzedowskii1.jpg">Female inflorescence of <i>Platanus rzedowskii</i></a>[<i>permanent dead link</i>]</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Christenhusz, M.J.M. & Byng, J.W. (2016). "The number of known plants species in the world and its annual increase". Phytotaxa. 261 (3): 201–217. doi:10.11646/phytotaxa.261.3.1. <a href="http://biotaxa.org/Phytotaxa/article/download/phytotaxa.261.3.1/20598" target="_blank">http://biotaxa.org/Phytotaxa/article/download/phytotaxa.261.3.1/20598</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> </ol>