Editing Peanut (section)

== Botanical description ==
[[File:Ground Nut flower.jpg|thumb|Peanut flower]]

The peanut is an [[Annual plant|annual]] [[herbaceous plant]] growing {{convert|30|to|50|cm|6=0}} tall.<ref name=putnam/> As a legume, it belongs to the botanical family [[Fabaceae]], also known as Leguminosae, and commonly known as the legume, bean, or pea family.<ref name="WFO"/> Like most other legumes, peanuts harbor symbiotic [[Nitrogen fixation|nitrogen-fixing]] bacteria in their [[root nodule]]s.<ref name="kew.org"/>

The [[leaves]] are [[Phyllotaxis|opposite]] and [[Pinnation|pinnate]] with four leaflets (two opposite pairs; no terminal leaflet); each leaflet is {{convert|1|to|7|cm|abbr=on|in|frac=4}} long and {{convert|1|to|3|cm|in|frac=4|abbr=on}} across. Like those of many other legumes, the leaves are [[Nyctinasty|nyctinastic]]; that is, they have "sleep" movements, closing at night.{{citation needed|date=June 2024}}

The flowers are {{convert|1|to|1.5|cm|in|frac=8|abbr=on}} across, and yellowish orange with reddish veining.<ref name="Krapovickas-2007" /><ref name=putnam/> They are borne in [[Axillary bud|axillary]] clusters on the stems above ground and last for just one day. The ovary is located at the base of what appears to be the flower stem but is a highly elongated [[Hypanthium|floral cup]].{{citation needed|date=June 2024}}

Peanut fruits develop underground, an unusual feature known as [[geocarpy]].<ref name="Smith-1950">{{cite journal |last=Smith |first=Ben W. |date=January 1, 1950 |title=Arachis hypogaea. Aerial Flower and Subterranean Fruit |jstor=2437758 |journal=American Journal of Botany |volume=37 |issue=10 |pages=802–815 |doi=10.2307/2437758}}</ref> After [[fertilization]], a short stalk at the base of the ovary—often termed a [[gynophore]], but which appears to be part of the ovary—elongates to form a thread-like structure known as a "peg". This peg grows into the soil, allowing the fruit to develop underground.<ref name="Smith-1950" /> These pods, technically called legumes, are {{convert|3|to|7|cm|in|frac=2}} long, normally containing one to four [[seed]]s.<ref name="Krapovickas-2007" /><ref name=putnam/> The shell of the peanut fruit consists primarily of a mesocarp with several large veins traversing its length.<ref name="Smith-1950" />[[File:Peanut plumule and radicle.jpg|thumb|Peanut seed separated showing the [[cotyledon]], [[plumule]] and [[radicle]]]]
Parts of the peanut include:
* [[Nutshell|Shell]] – outer covering, in contact with soil
* [[Cotyledon]]s (two) – the main edible part
* [[Seed coat]] – brown paper-like covering of the edible part
* [[Radicle]] – embryonic root at the bottom of the cotyledon, which can be snapped off
* [[Seedling|Plumule]] – embryonic shoot emerging from the top of the radicle

[[File:Peanuts (Arachis hypogaea) - in shell, shell cracked open, shelled, peeled.jpg|thumb|Peanuts]]

=== Peanut phytochemistry ===
Peanuts contain [[polyphenol]]s, [[polyunsaturated fat|polyunsaturated]] and [[monounsaturated fat|monounsaturated]] [[fat]]s, [[phytosterol]]s and [[dietary fiber]] in amounts similar to several tree nuts.<ref name="lpi">{{cite web |year=2009 |title=Nuts (including peanuts) |url=http://lpi.oregonstate.edu/mic/food-beverages/nuts |access-date=November 29, 2016 |series=Micronutrient Information Center |publisher=Linus Pauling Institute, Oregon State University |location=Corvallis, OR}}</ref> Peanut skins contain [[resveratrol]].<ref name="lpi-res">{{cite web |year=2016 |title=Resveratrol |url=http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/resveratrol |series=Micronutrient Information Center |publisher=Linus Pauling Institute, Oregon State University |location=Corvallis, OR}}</ref><ref>{{cite journal |last1=Sales |first1=J.M. |last2=Resurreccion |first2=A.V. |year=2014 |title=Resveratrol in peanuts |journal=Critical Reviews in Food Science and Nutrition |volume=54 |issue=6 |pages=734–770 |pmid=24345046 |s2cid=13183809 |doi=10.1080/10408398.2011.606928}}</ref>