Envoy at 04:04, 30 September 2007

2007-09-30T04:04:44Z

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:''This page refers to the U.S. pawpaw in the genus ''Asimina''. In some other parts of the world, the name pawpaw is applied to the unrelated tropical fruit [[papaya]] (''Carica papaya'').''
{{Taxobox
| color = lightgreen
| name = Pawpaw
| image = Asimina_triloba3.jpg
| image_width = 250px
| image_caption = Common Pawpaw in fruit
| regnum = [[Plant]]ae
| divisio = [[Flowering plant|Magnoliophyta]]
| classis = [[Magnoliopsida]]
| ordo = [[Magnoliales]]
| familia = [[Annonaceae]]
| genus = '''''Asimina'''''
| genus_authority = [[Michel Adanson|Adans.]]
| subdivision_ranks = Species
| subdivision = See text
}}

'''Pawpaw''' (''Asimina'') is a genus of eight or nine species of small [[tree]]s with large leaves and fruit, native to eastern [[North America]]. The genus includes the largest edible [[fruit]] indigenous to the continent. They are [[understory]] trees found in deep fertile bottomland and hilly upland habitat. Pawpaw is in the same family ([[Annonaceae]]) as the [[custard-apple]], [[cherimoya]], [[Sugar-apple|sweetsop]], and [[soursop]], and it is the only member of that family not confined to the [[tropics]].

==Names==
The name, also spelled '''paw paw''', '''paw-paw''', and '''papaw''', probably derives from the Spanish ''[[papaya]]'', perhaps due to the superficial similarity of their fruit. Pawpaw has numerous other common names, often very local, such as '''prairie banana''', '''Indiana banana''', '''Kentucky banana''', '''Michigan banana''', and '''Ozark banana'''.

==Description==
The pawpaws are shrubs or small trees, reaching heights of 2 to 12 m tall. The northern, cold-tolerant common pawpaw (''Asimina triloba'') is [[deciduous]], while the southern species are often [[evergreen]].

The [[leaf|leaves]] are alternate, simple ovate, entire, 20 to 35 cm long and 10 to 15 cm broad.

The [[Carrion flower|fetid]] [[flower]]s are produced singly or in clusters of up to eight together; they are large, 4 to 6 cm across, perfect, with six sepals and petals (three large outer petals, three smaller inner petals). The petal color varies from white to purple or red-brown.

The [[fruit]] is a large edible [[berry]], 5 to 16 cm long and 3 to 7 cm broad, weighing from 20 to 500 g, with numerous [[seed]]s; it is green when unripe, maturing to yellow or brown. It has a flavor somewhat similar to both [[banana]] and [[mango]], varying significantly by cultivar, and has more [[protein]] than most fruits.

* Bark: Dark brown, blotched with gray spots, sometimes covered with small excrescences, divided by shallow fissures. Inner bark tough, fibrous. Branchlets light brown, tinged with red, marked by shallow grooves.
* Wood: Pale, greenish yellow, sapwood lighter; light, soft, coarse-grained and spongy. Sp. gr., 0.3969; weight of cu. ft. 24.74 lbs.
* Winter buds: Small, brown, acuminate, hairy.
* Leaves: Alternate, simple, feather-veined, obovate-lanceolate, ten to twelve inches long, four to five broad, wedge-shaped at base, entire, acute at apex; midrib and primary veins prominent. They come out of the bud conduplicate, green, covered with rusty tomentum beneath, hairy above; when full grown are smooth, dark green above, paler beneath. In autumn they are a rusty yellow. Petioles short and stout with a prominent adaxial groove. Stipules wanting.
* Flowers: April, with the leaves. Perfect, solitary, axillary, rich red purple, two inches across, borne on stout, hairy peduncles. Ill smelling.
* Calyx: Sepals three, valvate in bud, ovate, acuminate, pale green, downy.
* Corolla: Petals six, in two rows, imbricate in the bud. Inner row acute, erect, nectariferous. Outer row broadly ovate, reflexed at maturity. Petals at first are green, then brown, and finally become dull purple and conspicuously veiny.
* Stamens: Indefinite, densely packed on the globular receptacle. Filaments short; anthers extrorse, two-celled, opening longitudinally.
* Pistils: Several, on the summit of the receptacle, projecting from the mass of stamens. Ovary one-celled; stigma sessile; ovules many.
* Fruit: September, October. Cotyledons broad, five-lobed.<ref name=Keeler>{{cite book
| last =Keeler
| first =Harriet L.
| title =Our Native Trees and How to Identify Them
| publisher =Charles Scriber's Sons
| date =1900
| location =New York
| pages =20-23 }}</ref>

== Cultivation==
[[Pollination|Pollinated]] by scavenging [[Blow-fly|carrion flies]] and [[beetle]]s, the flowers emit a weak scent which attracts few [[pollinator]]s, thus limiting fruit production.

Larger growers sometimes locate rotting meat near the trees at bloom time to increase the number of blowflies. ''Asimina triloba'' is the only larval host of the [[Zebra Swallowtail Butterfly]].

==Species==
* ''[[Asimina angustifolia]]'' [[Constantine Samuel Rafinesque|Raf.]] - '''Slimleaf Pawpaw'''. [[Florida]], [[Georgia (U.S. state)|Georgia]], and [[Alabama]].
* ''[[Asimina incana]]'' ([[W. Bartram]]) Exell - '''Woolly Pawpaw'''. Florida and Georgia.
* ''[[Asimina obovata]]'' ([[Carl Ludwig Willdenow|Willd.]]) [[George Valentine Nash|Nash]] - '''Bigflower Pawpaw'''. Florida.
* ''[[Asimina parviflora]]'' ([[André Michaux|Michx.]]) [[Dunal]] - '''Smallflower Pawpaw'''. Southern states from [[Texas]] to [[Virginia]].
* ''[[Asimina pygmea]]'' (W. Bartram) Dunal - '''Dwarf Pawpaw'''. Florida and Georgia.
* ''[[Asimina reticulata]]'' Shuttlw. ex Chapman - '''Netted Pawpaw'''. Florida and Georgia.
* ''[[Asimina tetramera]]'' [[John Kunkel Small|Small]] - '''Fourpetal Pawpaw'''. Florida {{StatusEndangered}}.
* ''[[Asimina triloba]]'' ([[Carolus Linnaeus|L.]]) Dunal - '''Common Pawpaw'''. Extreme southern [[Ontario]], [[Canada]], and the eastern [[United States]] from [[New York]] west to southeast [[Nebraska]], and south to northern Florida and eastern Texas.

==Cultivation and uses==
[[Image:Asimina triloba red fern farm.jpg|thumb|300px|''Asimina triloba'' is often called '''Prairie Banana''' because of its banana-like creamy texture and flavor.]]
The pawpaw's chosen home is in the shade of the rich bottom lands of the Mississippi valley, where it often forms a dense undergrowth in the forest. Where it dominates a tract it appears as a thicket of small slender trees, whose great leaves are borne so close together at the ends of the branches, and which cover each other so symmetrically, that the effect is to give a peculiar imbricated appearance to the tree.<ref name=Keeler />

Although it is a delicious and nutritious fruit, it has never been cultivated on the scale of apples and peaches, primarily because it does not store or ship well. It is also difficult to transplant due to its long [[taproot]]. [[Cultivar]]s are propagated by chip budding or whip [[grafting]].

In recent years the pawpaw has attracted renewed interest, particularly among [[organic farming|organic growers]], as a native fruit which has few pests, and which therefore requires little [[pesticide]] use for cultivation. The shipping and storage problem has largely been addressed by pulping the fruit and freezing the pulp. Among backyard gardeners it also is gaining in popularity because of the appeal of fresh fruit and because it is relatively low maintenance once planted. The pulp is used primarily in baked dessert recipes, as well as for brewing pawpaw beer.

The commercial growing and harvesting of pawpaws is strongest in southeast Ohio. The [http://www.ohiopawpaw.com Ohio Pawpaw Growers' Association] annually sponsors the [http://www.pawpawfest.com Ohio Pawpaw Festival] at Lake Snowden near [[Albany, Ohio]].

The flowers are self-incompatible, requiring cross [[pollination]]; at least two different varieties of the plant are needed as [[pollenizer]]s. The flowers produce an odor similar to that of [[decomposition|rotting]] [[meat]] to attract [[blowfly|blowflies]] or [[carrion beetle]]s for cross pollination. Lack of pollination is the most common cause of poor fruiting, and growers resort to hand pollination or to hanging chicken necks or other meat to attract [[pollinator]]s.

The leaves, twigs, and bark of the tree also contain natural insecticides known as [[acetogenin]]s, which can be used to make an organic pesticide{{Fact|date=February 2007}}. Acetogenins from pawpaw have also been investigated for their potent anticancer effects stemming from their ability to inhibit NADH oxidase.

This [[Clonal colony|colonial]] tree has a strong tendency to form colonial thickets if left unchecked.

==History==
The earliest documentation of pawpaws is in the 1541 report of the [[Hernando de Soto (explorer)|de Soto]] expedition, who found [[Native Americans in the United States|Native American]]s cultivating it east of the [[Mississippi River]]. The [[Lewis and Clark Expedition]] depended and sometimes subsisted on pawpaws during their travels. Chilled pawpaw fruit was a favorite [[dessert]] of [[George Washington]], and [[Thomas Jefferson]] was certainly familiar with it as he planted it at [[Monticello]]. In 2006, following lobbying by the Ohio Pawpaw Growers' Association, the [[Ohio House of Representatives]] passed a law that would have declared the pawpaw to be the state native fruit of Ohio. However, the [[Ohio Senate]] failed to act on the bill, resulting in its death.

==Medicinal properties==
[[Chemical compound|Compounds]] found in the bark and leaves of the pawpaw tree have been investigated and tested for anti-[[cancer]] properties because of the chemicals' effect on cell metabolism [http://www.self-helpcancer.org/cancertreatment2.htm#Pawpaw], particularly by Dr Jerry McLaughlin and his team at Purdue University [http://pawpaw.tv/McLaughlin_video_1.asp]. Growers hope that potential medical use will eventually lead to increased market demand from the [[Pharmacology|pharmaceutical]] industry.

In [[homeopathy]], ''Asimina triloba'' is used as remedy for [[Group A streptococcal infection|scarlet fever]] and red skin rashes.{{Fact|date=April 2007}}

The seeds also have insecticidal properties. The Native Americans dried and powdered them and applied the powder to childrens' heads to control lice; specialized shampoos now use compounds from pawpaw for the same purpose.

Recent research has shown that the fruit of plants in this family may lead to variants of [[Parkinson's Disease]] in animals, both in the wild and in labs. Further research is currently underway to prove or disprove these findings.<ref>{{cite news | title=Just A Little Tremble | author=Kevin Rayburn | url=http://php.louisville.edu/advancement/pub/impact/fall2006/parkinsons.php | work=Impact | date=Fall 2006 | publisher=University of Louisville}}</ref><ref>{{cite web | publisher=WebMD | work=Health News | title=Parkinson's Disease: Is It Something in the Air? | date=Nov. 5, 2000 | url=http://www.webmd.com/news/20001105/parkinsons-disease-is-something-in-air}}</ref><ref>{{ cite journal | title = Is atypical parkinsonism in the Caribbean caused by the consumption of Annonacae? | pmid = 17017523 | journal = J Neural Transm Suppl. | year = 2006 | pages = 153-7 | issue = 70 | author = Lannuzel A, Höglinger GU, Champy P, Michel PP, Hirsch EC, Ruberg M.}}</ref><ref>{{ cite journal | pmid = 10440304 | date = 1999 Jul 24 | volume = 354 | issue = 9175 | pages = 281-6 | title = Possible relation of atypical parkinsonism in the French West Indies with consumption of tropical plants: a case-control study | author = Caparros-Lefebvre D, Elbaz A.}}</ref>

==References==
{{reflist}}

==External links==
*[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=102827 Flora of North America ''Asimina'']
*[http://plants.usda.gov/java/profile?symbol=ASIMI USDA distribution of Pawpaw]
*[http://www.pawpaw.kysu.edu/ Pawpaw Information] from [[Kentucky State University]]
*[http://www.ars-grin.gov/cor/minor/asiinfo.html Asimina Genetic Resources]
*[http://www.pbs.org/lewisandclark/archive/journal-results.html?offset=1&corpall=all&clark=clark&dateall=day&indmonth=09&indday=18&indyear=1806&numpage=1 Clark's September 18, 1806 journal entry] about pawpaws
*[http://pawpaw.tv/McLaughlin_video_1.asp Paw Paw and Cancer - From Discovery to Clinical Trials] Presentation by Jerry McLaughlin Ph.D. on results of his research while at Purdue University
*[http://www.pawpawresearch.com/pawpawworks.htm How does paw paw work?] (medicine/cell biology/cell metabolism)
*[http://www.pawpawresearch.com/pawpaw-trials1.pdf A novel mechanism for the control of clinical cancer: Inhibition of the production of adenosine triphosphate (AT) with a standardized extract of paw paw (Asimicz triloba, Annonaceaea) ]
*[http://www.pawpawresearch.com/articles.htm Links to research on pharmaceutical uses of paw paw]
*[http://nymf.bbg.org/profile_species_nt.asp?id=188#medicinal Asimina triloba - Brooklyn Botanical Garden]
*[http://www.ars-grin.gov/ars/PacWest/Corvallis/ncgr/minor/asiinfo.html Asimina Genetic Resources - Pawpaw ]

{{commons|Asimina triloba}}

[[Category:Chemotherapeutic agents]]
[[Category:Fruit]]
[[Category:Magnoliales]]
[[Category:Plants and pollinators]]
[[Category:Trees of the United States]]
[[Category:Trees of Illinois]]
[[Category:Cuisine of the Southern United States]]

Pawpaw - Revision history

Envoy at 04:04, 30 September 2007