# Jeffersonia

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{{Short description|Genus of flowering plants belonging to the barberry family}}
{{Redirect|Twinleaf|the town in the Pokémon franchise|Pokémon regions#Sinnoh{{!}}Pokémon regions}}
{{Automatic taxobox
| name = Twinleaf
| image = Jeffersonia diphylla kz03.jpg
| taxon = Jeffersonia
| authority = [Barton](/source/Benjamin_Smith_Barton) 1793 not Brickell 1800 (syn of ''[Gelsemium](/source/Gelsemium)'' in [Loganiaceae](/source/Loganiaceae))
}}

'''''Jeffersonia''''', also known as '''twinleaf''' or '''rheumatism root''', is a small [genus](/source/genus) of [herbaceous](/source/herbaceous) [perennial plant](/source/perennial_plant)s in the family [Berberidaceae](/source/Berberidaceae). They are uncommon spring wildflowers and grow in [limestone](/source/limestone) soils of rich [deciduous forests](/source/Temperate_deciduous_forest). ''Jeffersonia'' was named for [United States President](/source/United_States_President) [Thomas Jefferson](/source/Thomas_Jefferson) by his contemporary [Benjamin Smith Barton](/source/Benjamin_Smith_Barton).<ref>[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=116785 Flora of North America: Jeffersonia]</ref> This genus was formerly grouped in genus ''[Podophyllum](/source/Podophyllum)''.  Twinleaf is protected by state laws as a threatened or endangered plant in [Georgia](/source/Georgia_(U.S._state)), [Iowa](/source/Iowa), [New York](/source/New_York_(state)), and [New Jersey](/source/New_Jersey).<ref>[https://plants.usda.gov/java/profile?symbol=JEDI USDA Plants Database: Jeffersonia]</ref>

== Description ==
''Jeffersonia diphylla'' has leaves and flowers that are smooth and emerge directly from the rhizome. The leaves are divided into two leaflets which are half-ovate in shape with entire or shallowly toothed margins.<ref name="CoffinPfannmuller1988">{{cite book|author1=Barbara Coffin|author2=Lee Pfannmuller|title=Minnesota's Endangered Flora and Fauna|url=https://books.google.com/books?id=wfWNq91AjeoC|year=1988|publisher=U of Minnesota Press|isbn=978-0-8166-1689-3|page=103}}</ref> It has showy white flowers with four sepals, eight [petals](/source/petals), eight stamens, and a singly pistil;<ref name="CoffinPfannmuller1988"/> the flower resembles [bloodroot](/source/bloodroot) flowers. The short-lived flower appears in April or May before the forest canopy appears  (see [spring ephemeral](/source/Ephemeral_plant)). The fruit is a green pear-shaped capsule with a hinged top. The characteristic leaves are large and nearly divided in half, giving rise to its common name, twinleaf. It rarely grows taller than {{convert|12|inch|cm}}.  As with other [deciduous forest](/source/temperate_deciduous_forest) plants, the seeds are dispersed by ants, a process known as [myrmecochory](/source/myrmecochory).

== Species ==
;accepted species<ref name=k>[http://www.theplantlist.org/tpl1.1/search?q=Jeffersonia The Plant List, search for ''Jeffersonia'']</ref>
*''Jeffersonia diphylla'' <small>(L.) Pers.</small> – Eastern North America especially Great Lakes region, Ohio Valley, and Appalachians<ref>[http://bonap.net/MapGallery/County/Jeffersonia%20diphylla.png Biota of North America Program 2013 county distribution map]</ref>

;unresolved names<ref name=k/>
*''Jeffersonia dubia'' <small>(Maxim.) Benth. & Hook. f. ex Baker & Moore</small> –  China, Korea, Russia (called ''[Plagiorhegma dubium](/source/Plagiorhegma_dubium)'' in [Flora of China](/source/Flora_of_China)<ref>[http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242338581 Flora of China Vol. 19 Page 783 <big>鲜黄连</big> xian huang lian ''Plagiorhegma dubium'' Maximowicz]</ref>)
*''Jeffersonia lobata'' <small>Nutt.</small>
*''Jeffersonia odorata'' <small>Raf.</small>

;species in homonymic genus<ref name=k/>
In 1800, Brickell used the name ''Jeffersonia'' to refer to some plants in the [Loganiaceae](/source/Loganiaceae), thus creating an illegitimate homonym.<ref>[http://www.tropicos.org/Name/40033270 Tropicos, ''Jeffersonia'' Brickell ]</ref> Species names coined using this illegitimate use of the name:
*''Jeffersonia sempervirens'' <small>Brickell</small>, now called ''[Gelsemium sempervirens](/source/Gelsemium_sempervirens)'' <small>(L.) J.St.-Hil</small>

==Distribution and habitat==
''Jeffersonia diphylla'' is native to Eastern North America where it is found from Minnesota east to New York and south to Tennessee.<ref name="CoffinPfannmuller1988"/> In Minnesota it grows in the lower southeastern section of the state in mesic deciduous forests and most commonly in ravines or on talus slopes.<ref name="CoffinPfannmuller1988"/> In Minnesota it has a preference for growing on calcareous soils of north and east-facing slopes and is listed as a threatened species.<ref name="CoffinPfannmuller1988"/> In Minnesota it is found in  association with other uncommon woodland plants such as ''Hydrastis canadensis'' ([golden seal](/source/Goldenseal)) and ''Dicentra canadensis'' ([squirrel-corn](/source/Dicentra_canadensis)).<ref name="CoffinPfannmuller1988"/>

== Uses ==
''Jeffersonia'' has had a variety of medical uses. One is hinted at by an archaic common name of ''Jeffersonia diphylla'', Rheumatism root. The roots of both species contain [berberine](/source/berberine), a known anti-tumor [alkaloid](/source/alkaloid).  The plant is therefore considered poisonous.

right|thumb|250px|A specimen of ''Jeffersonia diphylla'' in bloom.

=== America ===
[Native Americans](/source/Indigenous_peoples_of_the_Americas) use ''Jeffersonia diphylla'' for a variety of medicines.

The [Cherokee](/source/Cherokee) use an [infusion](/source/infusion) of this plant for treating [dropsy](/source/dropsy), as well as gravel and urinary tract problems, and as a poultice for sores and inflammation.<ref>Hamel, Paul B. and Mary U. Chiltoskey 1975 Cherokee Plants and Their Uses – A 400 Year History. Sylva, N.C. Herald Publishing Co. (p. 59)</ref>

The [Iroquois](/source/Iroquois) used a decoction of the plant to treat [gall](/source/gall) and [diarrhea](/source/diarrhea).<ref>Herrick, James William 1977 Iroquois Medical Botany. State University of New York, Albany, PhD Thesis (p. 332)</ref>

The whole plant was used in early American [medicine](/source/medicine) as an antispasmodic, diuretic, emetic, expectorant and general tonic. The "root" was once also used as an emetic in large doses, and as an expectorant in small doses.<ref>[http://www.pfaf.org/database/plants.php?Jeffersonia+diphylla Plants for a Future Database: ''J. diphylla'']</ref> Modern medicine does not use this plant.

==References==
{{Reflist}}

{{Berberidaceae genera}}
{{Taxonbar|from1=Q2562522|from2=Q15344873}}

Category:Berberidaceae
Category:Berberidaceae genera
Category:Monotypic Ranunculales genera
Category:Thomas Jefferson
Category:Taxa named by Benjamin Smith Barton

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Adapted from the Wikipedia article [Jeffersonia](https://en.wikipedia.org/wiki/Jeffersonia) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Jeffersonia?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.