Edit Plant: Toxicodendron

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'''''Toxicodendron''''' is a genus of [[flowering plant]]s in the [[sumac]] family, [[Anacardiaceae]]. It contains [[Woody plant|woody]] [[tree]]s, [[shrub]]s and [[vine]]s, including [[poison ivy]], [[poison oak]], and the [[lacquer tree]]. All members of the genus produce the skin-irritating oil [[urushiol]], which can cause a severe [[Allergy|allergic]] reaction. The generic name is derived from the [[Greek language|Greek]] words τοξικος (''toxikos''), meaning "poison," and δενδρον (''dendron''), meaning "tree."<ref>{{cite book |url=http://books.google.com/books?id=NJ6PyhVuecwC |title=The Names of Plants |first=D. |last=Gledhill |edition=4 |publisher=Cambridge University Press |isbn=9780521866453 |year=2008 |page=382}}</ref> Members of this genus are sometimes included in the genus ''[[Sumac|Rhus]]'', although recent molecular evidence points to keeping ''Toxicodendron'' as a separate [[Monophyly|monophyletic]] genus.<ref>{{cite web | url=http://etd.lsu.edu/docs/available/etd-04152004-101232/ | title=Molecular Systematics of the Cashew Family (Anacardiaceae) (PhD dissertation at Louisiana State University) | author=Pell, Susan Katherine | date=18 February 2004}}, page 89</ref> They have [[pinnate]]ly compound, alternate leaves and whitish or grayish [[drupe]]s. The best known members of the genus in [[North America]] are poison ivy, practically ubiquitous throughout most of [[east]]ern [[North America]], and [[Toxicodendron diversilobum|poison oak]], similarly ubiquitous throughout much of the [[west]]ern part of the [[continent]]. The plants are quite variable in appearance. The leaves may have smooth, toothed or lobed edges, and all three types of leaf edge may be present in a single plant. The plants grow as creeping vines, climbing vines, shrubs, or, in the case of Lacquer Tree and [[Poison sumac|Poison Sumac]], as trees. While leaves of poison ivy and poison oaks usually have three leaflets, sometimes there are five or, occasionally, even seven leaflets. Leaves of Poison Sumac have 7–13 leaflets, and of Lacquer Tree, 7–19 leaflets. The common names come from similar appearances to other species that are not closely related and to the allergic response to the urushiol. Poison oak is not an [[oak]] (''Quercus'', family [[Fagaceae]]), but this common name comes from the leaves' resemblance to white oak (''[[Quercus alba]]'') leaves, while Poison ivy is not an [[ivy]] (''Hedera'', family [[Araliaceae]]), but has a superficially similar growth form. Technically, the plants do not contain a [[poison]]; they contain a potent [[allergen]]. The [[resin]]s of certain species native to [[Japan]], [[China]] and other [[Asia]]n [[countries]], such as ''T. vernicifluum'' ([[Lacquer Tree]]) and ''T. succedaneum'' ([[Wax Tree]]), are used to make [[lacquer]], and, as a [[byproduct]] of lacquer [[manufacture]], their berries are used to make [[japan wax]]. {{Inc| Toxicodendron (Greek, poison tree): Hyaenanche, but by some retained as the tenable name. This Toxicodendron dates from 1796, but the Toxicodendron of Tournefort and Miller is much earlier and is revived by some botanists for the poison sumac and poison ivy (T. Vernix and T. radicans) and their kin but which in this book are still retained in Rhus. T. capense, Thunb., a very different plant and one of the Euphorbiaceae, is treated under Hyaenanche, Vol. III, page 1618. {{SCH}} }} ==Cultivation== {{edit-cult}}<!--- Type cultivation info below this line, then delete this entire line --> ===Propagation=== {{edit-prop}}<!--- Type propagation info below this line, then delete this entire line --> ===Pests and diseases=== {{edit-pests}}<!--- Type pest/disease info below this line, then delete this entire line --> ==Species== Select species: *''[[Toxicodendron acuminatum]]'' (or ''Rhus acuminata'') grows in [[China]], [[Bhutan]], [[India]] and [[Nepal]]. *[[Toxicodendron diversilobum|Western Poison oak]] (''Toxicodendron diversilobum'' or ''Rhus diversiloba'') is found throughout much of western [[North America]], ranging from the [[Pacific coast]] into the [[Sierra Nevada (U.S.)|Sierra Nevada]] and [[Cascades|Cascade]] [[mountain range]]s between southern [[British Columbia]] and southward into [[Baja California (peninsula)|Baja California]]. It is extremely common in that region, where it is the predominant species of the genus. Indeed, it is California's most prevalent woody shrub.<ref>{{cite web | url=http://nac.tamu.edu/x075bb/caddo/frameidx.html | title=The Toxicodendrons: Poison Ivy, Poison Oak and Poison Sumac | author=Brooks, Bill | date=4 March 1999}}</ref> Extremely variable, it grows as a dense shrub in open sunlight, or as a climbing vine in shaded areas. It propagates by creeping [[rhizome]]s or by seed.<ref>C.Michael Hogan (2008) ''Western poison-oak: Toxicodendron diversilobum'', GlobalTwitcher, ed. Nicklas Stromberg [http://globaltwitcher.auderis.se/artspec_information.asp?thingid=82914]</ref> The compound leaves are divided into three leaflets, 35–100&nbsp;mm long, with scalloped, toothed, or lobed edges. Californians learn to recognize it by the rhyme "leaves of three, let it be". The leaves may be red, yellow, green, or some combination of those colors, depending on various factors, such as the time of year. *[[Asian Poison ivy]] (''Toxicodendron orientale'', ''Rhus orientale'' or ''R. ambigua'') is very similar to the American Poison ivy, and replaces it throughout east Asia (so similar that some texts treat it as just a variety of the American species). *''[[Toxicodendron parviflorum]]'' (or ''Rhus parviflora''). *[[Potanin's Lacquer Tree]] or Chinese Varnish Tree (''Toxicodendron potaninii'' or ''Rhus potaninii'') from central China, is similar to ''T. vernicifluum'' but with (usually) fewer leaflets per leaf. Growing up to 20 m tall, like ''T. vernicifluum'' it is used for [[lacquer]] production. The leaves have 7–9 leaflets. *[[Atlantic Poison oak]] (''Toxicodendron pubescens'' or ''Rhus toxicarium'') grows mostly in sandy soils in eastern parts of the United States. Growing as a shrub, its leaves are in groups of three. Leaves are typically rounded or lobed, and are densely haired. Although it is often confused with the more common poison ivy, even in the scientific literature<ref>{{cite web | author=Sullivan, Janet | url=http://www.fs.fed.us/database/feis/plants/shrub/toxtox/all.html | title=Toxicodendron toxicarium | work=Fire Effects Information System | publisher=U.S. Department of Agriculture, Forest Service, [[Rocky Mountain Research Station]], Fire Sciences Laboratory | date=1994 }}</ref>, Atlantic Poison oak has small clumps of hair on the veins on the underside of the leaves, while Poison ivy does not. *[[Poison ivy (plant)|Poison ivy]] (''Toxicodendron radicans'' or ''Rhus radicans'') is extremely common in some areas of North America. In the United States it grows in all states east of the Rockies except North Dakota. It also grows in Central America. Appearing as a creeping vine, a climbing vine, or a shrub, it reproduces both by creeping rootstocks and by seeds. The appearance varies. Leaves, arranged in an alternate pattern, usually in groups of three, are from 20 to 50&nbsp;mm long, pointed at the tip, and may be toothed, smooth, or lobed, but never serrated. Leaves may be shiny or dull, and the color varies with the season. Vines grow almost straight up rather than wrapping around their support, and can grow to 8–10 m in height. In some cases, Poison ivy may entirely engulf the supporting structure, and vines may extend outward like limbs, so that it appears to be a Poison ivy "tree". *[[Western Poison ivy]] (''Toxicodendron rydbergii'' or ''Rhus rydbergii'') is found in northern parts of the eastern United States. It also exists in the western United States and Canada, but is much less common than Poison oak. It may grow as a vine or a shrub. It was once considered a subspecies of Poison ivy. It does sometimes hybridize with the climbing species. Western Poison ivy is found in much of western and central United States and Canada, although not on the West Coast. In the eastern United States it is rarely found south of New England. *Manzanillo (''[[Toxicodendron striatum]]'' or ''Rhus striata'') is a [[South America]]n poisonous tree growing in the [[tropical rain forests]] on low elevation slopes. *[[Wax Tree]] (''Toxicodendron succedaneum'' or ''Rhus succedanea''), a native of Asia, although it has been planted elsewhere, most notably Australia and New Zealand. It is a large shrub or tree, up to 8 m tall, somewhat similar to a sumac tree. Because of its beautiful autumn foliage, it has been planted outside of Asia as an [[ornamental plant]], often by gardeners who were apparently unaware of the dangers of allergic reactions. It is now officially classified as a noxious weed in Australia and New Zealand. The fatty-acid methyl ester of the kernel oil meets all of the major [[biodiesel]] requirements in the USA (ASTM D 6751-02, ASTM PS 121-99), Germany (DIN V 51606) and European Union (EN 14214).<ref>http://dx.doi.org/10.1016/j.biombioe.2005.05.001</ref> *''[[Toxicodendron sylvestre]]'' (or ''Rhus sylvestris'') grows in [[China]], [[Japan]], [[Korea]] and [[Taiwan]]. *[[Lacquer Tree]] or Varnish Tree (''Toxicodendron vernicifluum'' or ''Rhus verniciflua'') grows in Asia, especially China and Japan. Growing up to 20 m tall, its sap produces an extremely durable [[lacquer]]. The leaves have 7–19 leaflets (most often 11–13). The sap contains the allergenic oil, urushiol. Urushiol gets its name from this species which in [[Japanese language|Japanese]] is called ''Urushi''. Other names for this species include Japanese lacquer tree, Japanese Varnish Tree and Japanese Sumac (Note: the term "varnish tree" is also occasionally applied to the [[Candlenut]], ''Aleurites moluccana'', a southeast Asian tree unrelated to ''Toxicodendron''). *[[Poison Sumac]] (''Toxicodendron vernix'' or ''Rhus vernix'') is a tall shrub or a small tree, from 2–7 m tall. It is found in swampy, open areas and reproduces by seeds. The leaves have between 7–13 untoothed leaflets, in a [[pinnate|feather-compound]] arrangement.<ref>{{cite book | title=A Field Guide to Eastern Trees | author=George A. Petrides | isbn=0-395-90455-2 | year=1998}}</ref> In terms of its potential to cause [[urushiol-induced contact dermatitis]], poison sumac is far more virulent than other ''Toxicodendron'' species, even more virulent than poison ivy and poison oak. According to some botanists, poison sumac (''Toxicodendron vernix'') is the most [[Toxin|toxic]] plant species in the United States (Frankel, 1991). ==Gallery== {{photo-sources}}<!-- remove this line if there are already 3 or more photos in the gallery --> <gallery> Image:Upload.png| photo 1 Image:Upload.png| photo 2 Image:Upload.png| photo 3 </gallery> ==References== *[[Standard Cyclopedia of Horticulture]], by L. H. Bailey, MacMillan Co., 1963 <!--- xxxxx *Flora: The Gardener's Bible, by Sean Hogan. Global Book Publishing, 2003. ISBN 0881925381 --> <!--- xxxxx *American Horticultural Society: A-Z Encyclopedia of Garden Plants, by Christopher Brickell, Judith D. Zuk. 1996. ISBN 0789419432 --> <!--- xxxxx *Sunset National Garden Book. Sunset Books, Inc., 1997. ISBN 0376038608 --> ==External links== *{{wplink}} {{stub}} __NOTOC__

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