Juglans regia

The genus name, Juglans, is derived from two Latin words, jovis, which means Jupiter, the chief god of the ancient Roman religion; and glans meaning an acorn or nut. The specific epithet, regia, is defined as regal or royal in references the quality of the fruit and edible nuts.

Juglans regia is a large deciduous tree, attaining heights of {{convert|10-25|m|abbr=off|round=5}}, and a trunk up to {{convert|2|m|ft|abbr=on|frac=2}} in diameter, commonly with a short trunk and broad crown.{{cite book | last=Mitchell | first=Alan F. |author-link=Alan Mitchell (botanist) | title=A Field Guide to the Trees of Britain and Northern Europe | publisher=Collins | publication-place=London | date=1974 | isbn=0-00-212035-6 | page=195}}{{cite book | last=Rushforth | first=Keith | title=Trees of Britain and Europe | publisher=Trafalgar Square Publishing | publication-place=London | date=1999 | isbn=0-00-220013-9 | page=755}} The tallest accurately measured specimen is in Lagodekhi Protected Areas in Georgia, {{convert|29|m|abbr=on}} tall, and the stoutest, {{convert|9|m|abbr=on}} girth ({{convert|2.87|m|abbr=on}} diameter);{{cite web | title=The thickest, tallest, and oldest Persian Walnuts (Juglans regia) | website=Monumental Trees | url=https://www.monumentaltrees.com/en/trees/juglansregia/records/ | access-date=2024-11-07}} heights of 34 m in the wild in Kyrgyzstan,{{cite journal |last1=Hemery |first1=Gabriel E. |author1-link=Gabriel Hemery |date=1998 |title=Walnut (Juglans regia) seed-collecting expedition to Kyrgyzstan in Central Asia |journal=Quarterly Journal of Forestry |volume=92 |issue=2 |pages=153–157}} and 32 m in cultivation in Britain{{cite book | last=Mitchell | first=Alan F. |author-link=Alan Mitchell (botanist) | title=Alan Mitchell's Trees of Britain | publisher=HarperCollins | date=1996 | isbn=0-00-219972-6 | pages=246–249}} have been reported, but not verified.

The bark is smooth, olive-brown when young and silvery-grey on older branches, and features scattered broad fissures with a rougher texture. Like all walnuts, the pith of the twigs contains air spaces; this chambered pith is creamy-white at first, becoming brown in older twigs. The leaves are alternately arranged, {{convert|20|–|45|cm|abbr=on|frac=2}} long, odd-pinnate with (3–)5–9 (most often 7) leaflets, arranged in opposite pairs with one terminal leaflet. The largest leaflets are the three at the apex, {{convert|10|–|20|cm|abbr=on|frac=2}} long and {{convert|6|–|10|cm|abbr=on|frac=2}} broad; the basal pair of leaflets are much smaller, {{convert|5|–|8|cm|abbr=on|frac=2}} long. The margins of the leaflets are entire, but with toothed margins on seedlings, and in the cultivar 'Laciniata'. The leaves open fairly late in the spring (typically mid May in Britain), and are red-brown at first, becoming their mature dark yellow-toned green by mid June. The male flowers are in drooping catkins {{convert|5|–|10|cm|abbr=on|frac=2}} long, and the female flowers are terminal, in clusters of two to five, ripening in the autumn into a fruit with a green, semi-fleshy husk and a brown, corrugated nut. The whole fruit, including the husk, falls in autumn with the husk breaking open; the seed is a large and edible nut with a rich flavour; the shell is thick in wild populations, while most cultivated plants have been selected for a thin shell.

{{gallery|mode=packed

|Noix-noyer.jpg|Seedling; note the serrated leaf margins

|Juglans regia young.jpg|Young tree

|Juglans-regia-total.JPG|Mature tree

|Bark of Juglans regia 01.jpg|Bark

|Juglans-regia-buds.jpg|Buds

|20150423Juglans regia1.jpg|The new leaves in spring have a distinctive red-brown colour at first

|Walnuss_Blüte.jpg|Male flower

|Juglans flower female 20050526 064.jpg|Female flower

|Juglans regia 04.JPG|Fertilized flowers

|Juglans-regia.JPG|Foliage

|Juglans regia 2009 G2.jpg|Fruit

|Juglans regia Echte Walnußfrucht 3.JPG|Seed

|Juglans regia autumn 2009.jpg|Habit (autumn)

|Blanzac-Porcheresse 16 Noyers 2008.jpg|In winter, France

|Walnussbaum-alt.jpg|Old tree

}}

File:Oldest Walnut tree in the world. Khotan, Xinjiang.jpg, Xinjiang, China, in 2011]]

File:Ořešák královský (Juglans regia).jpg]]

One of the centres of origin and diversity of J. regia is Iran,{{Cite web |title=Juglans regia L. {{!}} Plants of the World Online {{!}} Kew Science |url=http://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:442427-1 |access-date=2024-03-18 |website=Plants of the World Online |language=en}}{{Cite journal|last=ResearchGate|date=November 2014|title=Nutritive Value of Persian Walnut (Juglans regia L.) Orchards|url=https://www.researchgate.net/publication/268449164|journal=ResearchGate}} and another further northeast in Central Asia. In Central Asia, genetic diversity is very patchy, with the highest diversity found around Sariosiyo in Uzbekistan, and conspicuously lower in the Arslanbob forests in Kyrgyzstan (these now thought to be of cultivated origin). Another native glacial refugium population with high genetic diversity is found on the southern fringes of the Alps in northeast Italy. However, as with other old and widespread cultivated plants, it is not easy to reconstruct the original distribution and determine the borders of the past natural ranges. There are many reports concerning the earliest fossil pollen and nuts of J. regia, and the conclusions that various authors draw are somewhat contradictory. Taken together these finds suggest that J. regia possibly survived the last glaciations in several refugia, as the compilation of the data shows most likely southern Europe, the Near East, China, and the Himalaya.{{Cite journal|last1=Beer|first1=Ruth|last2=Kaiser|first2=Franziska|last3=Schmidt|first3=Kaspar|last4=Ammann|first4=Brigitta|last5=Carraro|first5=Gabriele|last6=Grisa|first6=Ennio|last7=Tinner|first7=Willy|date=2008-03-01|title=Vegetation history of the walnut forests in Kyrgyzstan (Central Asia): natural or anthropogenic origin?|url=http://www.sciencedirect.com/science/article/pii/S0277379107003484|journal=Quaternary Science Reviews|language=en|volume=27|issue=5|pages=621–632|doi=10.1016/j.quascirev.2007.11.012|bibcode=2008QSRv...27..621B|issn=0277-3791}}

The largest forests are in Kyrgyzstan, where trees occur in extensive forests at {{cvt|1,000–2,000|m|ft|-2}} altitude, notably at Arslanbob in Jalal-Abad Province.{{cite web | last=Soni | first=Mayank | title=The world's largest walnut harvest | website=BBC Home | date=2019-11-27 | url=https://www.bbc.com/travel/article/20191126-the-worlds-largest-walnut-harvest | access-date=2024-11-07}}

In the fourth century BC, Alexander the Great introduced this "Persian nut" (Theophrastus' καρυα ή Περσική)Theophrastus, Enquiry into Plants III.6.2, III.14.4 in Macedonian, Ancient Greek ancestral forms with lateral fruiting from Iran and Central Asia. They hybridized with terminal-bearing forms to give lateral-bearing trees with larger fruit.{{Clarify|date=January 2013}} These lateral-bearers were spread in southern Europe and northern Africa by Romans. Recent prospections in walnut populations of the Mediterranean Basin allowed to select interesting trees of this type. In the Middle Ages, the lateral-bearing character was introduced again in southern Turkey by merchants travelling along the Silk Road. J. regia germplasm in China is thought to have been introduced from Central Asia about 2,000 years ago, and in some areas has become naturalised. Cultivated J. regia was introduced into western and northern Europe very early, probably in Roman times, and to the Americas in the 17th century, by European colonists. Important nut-growing regions include California in the United States; France, Serbia, Greece, Bulgaria, Romania and Hungary in Europe; China in Asia; Baja California and Coahuila in Mexico; and Chile in Latin America. Lately, cultivation has spread to other regions, such as New Zealand and the southeast of Australia.{{cite web | url= http://www.fao.org/docrep/007/y5704e/y5704e03.htm | title= FAO corporate document repository: Walnut}} It is cultivated extensively from 30° to 50° of latitude in the Northern Hemisphere and from 30° to 40° in the Southern Hemisphere. Its high-quality fruits are eaten both fresh or pressed for their richly flavoured oil; numerous cultivars have been selected for larger nuts with thinner shells.{{cite book |last=Huxley |first=Anthony |title=Dictionary of Gardening (Royal Horticultural Society, UK) |date=1992 |publisher=Macmillan Press; Stockton Press |isbn=1-56159-001-0 |publication-place=London; New York |page=}}

J. regia is highly diverse genetically, and has been extensively cultivated for possibly as long as 2,000 years in parts of west Asia and southern Europe.{{cite journal | last1=Gaisberger | first1=Hannes | last2=Legay | first2=Sylvain | last3=Andre | first3=Christelle | last4=Loo | first4=Judy | last5=Azimov | first5=Rashid | last6=Aaliev | first6=Sagynbek | last7=Bobokalonov | first7=Farhod | last8=Mukhsimov | first8=Nurullo | last9=Kettle | first9=Chris | last10=Vinceti | first10=Barbara | title=Diversity Under Threat: Connecting Genetic Diversity and Threat Mapping to Set Conservation Priorities for Juglans regia L. Populations in Central Asia | journal=Frontiers in Ecology and Evolution | volume=8 | date=2020-06-23 | issn=2296-701X | doi=10.3389/fevo.2020.00171 | doi-access=free | page=| hdl=20.500.11850/425973 | hdl-access=free }}{{cite journal | last1=Vischi | first1=Massimo | last2=Chiabà | first2=Cristina | last3=Raranciuc | first3=Steluta | last4=Poggetti | first4=Luca | last5=Messina | first5=Rachele | last6=Ermacora | first6=Paolo | last7=Cipriani | first7=Guido | last8=Paffetti | first8=Donatella | last9=Vettori | first9=Cristina | last10=Testolin | first10=Raffaele | title=Genetic Diversity of Walnut (Juglans regia L.) in the Eastern Italian Alps | journal=Forests | volume=8 | issue=3 | date=2017-03-16 | issn=1999-4907 | doi=10.3390/f8030081 | doi-access=free | page=81| bibcode=2017Fore....8...81V | hdl=11390/1103388 | hdl-access=free }}

Its closest relative is Juglans sigillata from western China and the far northeast of India;{{cite book | last1=Aradhya | first1=Mallikarjuna K. | last2=Potter | first2=Daniel | last3=Simon | first3=Charles J. | title=Darwin's Harvest | chapter=7. Cladistic Biogeography of Juglans ( Juglandaceae) Based on Chloroplast DNA Intergenic Spacer Sequences | publisher=Columbia University Press | date=2006-12-31 | doi=10.7312/motl13316-008 | pages=143–170 | isbn=978-0-231-16891-5 |url=https://corpora.tika.apache.org/base/docs/govdocs1/443/443893.pdf }} it differs chiefly in leaves with 9–11 leaflets, and nuts with a much thicker, harder shell.{{cite book | last1=Grimshaw | first1=John | last2=Bayton | first2=Ross | title=New Trees | publisher=Royal Botanic Gardens Kew | publication-place=Richmond, Surrey | date=2009 | isbn=978-1-84246-173-0 | oclc=428774409 | pages=413–414}}

It tends to grow taller and narrower in dense forest competition. It is a light-demanding species, requiring full sun to grow well.

Juglans regia is infested by Rhagoletis juglandis, commonly known as the walnut husk fly, which lays its eggs in the husks of walnut fruit.Boyce, A.M. (December 1929). "The Walnut Husk Fly (Rhagoletis juglandis Cresson)". Journal of Economic Entomology. 22 (6): 861–866. doi:10.1093/jee/22.6.861.

Other plants often will not grow under walnut trees because the fallen leaves and husks contain juglone, a chemical which acts as a natural herbicide. Horses that eat walnut leaves may develop laminitis, a hoof ailment.{{citation needed|date=August 2024}}

Walnut trees grow best in rich, deep soil with full sun and long summers, such as the California central valley. Juglans hindsii and J. hindsii × J. regia are often used as grafting stock for J. regia.{{cite web |date=2021 |title=Walnuts in California |url=http://fruitandnuteducation.ucdavis.edu/fruitnutproduction/Walnut|archiveurl=https://web.archive.org/web/20201117081052/http://fruitandnuteducation.ucdavis.edu/fruitnutproduction/Walnut/ |access-date=23 January 2021 |archivedate= 17 November 2020|publisher=Fruit and Nut Research and Information Center, University of California at Davis}} Mature trees may reach {{convert|50|ft|abbr=on|order=flip}} in height and width, and live more than 200 years, developing massive trunks more than {{convert|8|ft|abbr=on|order=flip}} thick.

{{gallery|mode=packed

|FLORY 34 Series Nut Sweeper-8976.jpg|FLORY 34 Series Nut Sweeper during harvest in Glenn County, California

|FLORY 8770 Harvester in walnut orchard-9090.jpg|FLORY 8770 Harvester during walnut harvest in Glenn County

}}

{{further|Walnut#Cultivars}}

Walnut cultivars include:

{{columns-list|colwidth=12em|

• Purpurea
• Broadview
• Cascade
• Allegheny
• Bedco 1
• Coble #2
• Hansen
• Kaiser
• KY Giant
• Lake
• McKinster
• Somers
• Utah Giant
• Colby
• Greenhaven
• Reda
• Shiawassee
• Perry
• S-1
• Looking Glass
• China-B
• Champion
• Northern Prize
• Placentia
• Zijing

}}

Particular cultivars of J. regia may be more infested by R. juglandis than others because of varying walnut husk softness or thickness. 'Eureka', 'Klondike', 'Payne', 'Franquette' and 'Ehrhardt' cultivars are among the most susceptible to infestation.Boyce, A.M. (December 1929). "The Walnut Husk Fly (Rhagoletis juglandis Cresson)". Journal of Economic Entomology. 22: 861–866.

In 2022, world production of shelled walnuts was 3.9 million tonnes, led by China with 36% of the total harvested, with the United States, Iran, and Turkey as secondary producers (table).

Walnuts and other tree nuts are food allergen sources having potential to cause life-threatening, IgE-mediated allergic reactions in some individuals.{{cite web |date=18 October 2006 |title=Allergy information for walnut (Juglans regia) |url=http://research.bmh.manchester.ac.uk/informall/allergenic-food/index.aspx?FoodId=53 |access-date=22 January 2021 |publisher=Manchester Academic Health Science Centre, University of Manchester}}{{cite journal |last1=Teuber |first1=Suzanne S. |last2=Jarvis |first2=Koren C. |last3=Dandekar |first3=Abhaya M. |last4=Peterson |first4=W. Rich |last5=Ansari |first5=Aftab A. |year=1999 |title=Identification and cloning of a complementary DNA encoding a vicilin-like proprotein, Jug r 2, from English walnut kernel (Juglans regia), a major food allergen |journal=Journal of Allergy and Clinical Immunology |volume=104 |issue=6 |pages=1311–1320 |doi=10.1016/S0091-6749(99)70029-1 |pmid=10589017|doi-access=free }}

{{nutritional value

| name = Unroasted walnuts

| kcal = 654

| water = 4.1 g

| protein = 15.2 g

| fat = 65.2 g

| satfat = 6.1 g

| monofat = 8.9 g

| polyfat = 47.2 g

| omega3fat = 9.1 g

| omega6fat = 38.1 g

| carbs = 13.7 g

| fibre = 6.7 g

| sugars = 2.6

| copper_mg = 1.6

| calcium_mg = 98

| iron_mg = 2.9

| magnesium_mg = 158

| phosphorus_mg = 346

| potassium_mg = 441

| sodium_mg = 2

| zinc_mg = 3.1

| manganese_mg = 3.4

| selenium_ug = 4.9

| vitC_mg = 1

| thiamin_mg = 0.34

| riboflavin_mg = 0.15

| niacin_mg = 1.13

| pantothenic_mg = 0.57

| vitB6_mg = 0.54

| folate_ug = 98

| choline_mg = 39.2

| vitE_mg = 0.7

| vitK_ug = 2.7

| note = [https://fdc.nal.usda.gov/food-details/2346394/nutrients Link to USDA Database entry]

}}

Walnut kernels are 4% water, 65% fat, 15% protein, and 14% carbohydrates. In a reference amount of {{cvt|100|g}} providing 654 calories, the kernels supply several micronutrients in rich amounts (20% or more of the Daily Value, DV), including the dietary minerals manganese, phosphorus, magnesium, zinc, and copper, among others; B vitamins B6, thiamine, and folate; and dietary fibre.

The fatty acid composition includes 6% saturated fats, 10% monounsaturated fats, and 49% polyunsaturated fats (USDA source).

As with all species of walnut, the green outer husk of the fruit is rich in a yellow-brown to dark brown dye; harvesting the nuts often leaves the fingers strongly stained brown, and an extract from the husks can be used for dyeing cloth. The dye has notable antibacterial properties.{{cite journal | last1=Mirjalili | first1=Mohammad | last2=Karimi | first2=Loghman | title=Extraction and Characterization of Natural Dye from Green Walnut Shells and Its Use in Dyeing Polyamide: Focus on Antibacterial Properties | journal=Journal of Chemistry | publisher=Wiley | volume=2013 | issue=1 | year=2013 | issn=2090-9063 | doi=10.1155/2013/375352 | doi-access=free | page=}}

Walnut heartwood is a heavy, hard, open-grained hardwood. Freshly cut live wood may be Dijon-mustard colour, darkening to brown over a few days. The dried lumber is a rich chocolate-brown to black, with cream to tan sapwood, and may feature unusual figures, such as "curly", "bee's wing", "bird's eye", and "rat tail", among others. It is prized by fine woodworkers for its durability, lustre and chatoyance, and is used for high-end flooring, guitars, furniture, veneers, knobs and handles as well as gunstocks.{{cite web | url=https://www.extension.iastate.edu/smallfarms/harvesting-walnut | title=Harvesting Walnut }}

In Skopelos, a Greek island in the Aegean Sea, local legend suggests whoever plants a walnut tree will die as soon as the tree can "see" the sea.{{cite news |title=Skopelos is not for tourists, it is for lovers – Epifanios Skiathitis writes about his island |url=https://www.travel.gr/en/insiders-en/skopelos-is-not-for-tourists-it-is-for-lovers-epifanios-skiathitis-writes-about-his-island/ |access-date=4 August 2023 |work=Travel.gr |date=8 September 2021 |language=en}} Most planting is done by field rats (subfamily Murinae). In Flanders, a folk saying states: "By the time the tree is big, the planter surely will be dead." ({{langx|nl|Boompje groot}}, plantertje dood). These sayings refer to the relatively slow growth rate and late fruiting of the tree.{{cite web |title=Column stadsboswachter Maurice: Plantertje groot, boompje dood |url=https://www.natuurmonumenten.nl/natuurgebieden/zuidpolder/nieuws-0 |website=Natuurmonumenten |access-date=4 August 2023 |language=nl |date=30 January 2020}}

Benevento in southern Italy is the home of an ancient tradition of stregoneria. The witches of Benevento were reputed to come from all over Italy to gather for the Witches' Sabbath under the sacred walnut tree of Benevento. In 1526, Judge Paolo Grillandi wrote of witches in Benevento who worship a goddess at the site of an old walnut tree.Grimassi, Raven. Encyclopedia of Wicca & Witchcraft. Llewellyn Worldwide (2000). p. 454. This legend inspired many cultural works, including the 1812 ballet Il Noce di Benevento (the walnut tree of Benevento) by Salvatore Viganò and Franz Xaver Süssmayr, a theme from which was adapted into a violin piece called Le Streghe by Niccolò Paganini.{{cite journal |last1=Gooley |first1=Dana |title="La Commedia del Violino": Paganini's Comic Strains |journal=The Musical Quarterly |date=2005 |volume=88 |issue=3 |pages=370–427 |doi=10.1093/musqtl/gdi012 |jstor=4123230 |url=https://www.jstor.org/stable/4123230 |access-date=4 August 2023 |issn=0027-4631}} The Beneventan liqueur Strega depicts on its label the famous walnut tree with the witches dancing under it.{{cite web |title=Liquore Strega |url=https://www.strega.it/en/liquore-strega/ |website=Strega Alberti Benevento SpA |access-date=4 August 2023}}

{{See also|Walnut}}File:Juglans regia - Köhler–s Medizinal-Pflanzen-081.jpg

The Latin name for the walnut was nux Gallica, "Gallic nut";{{cite web |date=2021 |title=Walnut |url=https://www.etymonline.com/search?q=walnut |publisher=Online Etymology Dictionary}} the Gaulish region of Galatia in Anatolia lies in highlands at the western end of the tree's presumed natural distribution.

Although often called simply "walnut", this does not distinguish the tree from other species of Juglans. Internationally, it is most often called "common walnut" or "Persian walnut";{{cite web |date=2021-09-28 |title=Persian walnut (Juglans regia) |url=https://www.inaturalist.org/taxa/63935-Juglans-regia |access-date=2024-11-07 |website=iNaturalist}}{{cite web |author=L.C. van Zyl |date=2009 |title=Grafting of Walnut (Juglans regia L.) with Hot Callusing Techniques Under South African Conditions |url=http://etd.uovs.ac.za/ETD-db//theses/available/etd-09172009-160603/unrestricted/VanZylLC.pdf |url-status=dead |archive-url=https://web.archive.org/web/20120907120748/http://etd.uovs.ac.za/ETD-db/theses/available/etd-09172009-160603/unrestricted/VanZylLC.pdf |archive-date=2012-09-07 |access-date=2011-03-06 |publisher=University of the Free State}}{{cite web |title=Walnuts: Australia - Nuts |url=http://www.austnuts.com.au/walnuts.html |url-status=dead |archive-url=https://web.archive.org/web/20101129025836/http://www.austnuts.com.au/walnuts.html |archive-date=2010-11-29 |access-date=2012-08-23 |publisher=Austnuts.com.au}} other names include "Madeira walnut",{{GRIN|access-date=2019-07-06}} and "English walnut" mainly in North America,{{cite web |title=USDA Plants Database |url=https://plants.sc.egov.usda.gov/plant-profile/JURE80 |access-date=2024-11-08 |website=USDA Plants Database}} possibly because English sailors were prominent in Juglans regia nut distribution at one time.{{cite web |title=English walnuts - profile |url=http://www.agmrc.org/agmrc/commodity/nuts/englishwalnut/englishwalnutsprofile.htm |url-status=dead |archive-url=https://web.archive.org/web/20060928013143/http://www.agmrc.org/agmrc/commodity/nuts/englishwalnut/englishwalnutsprofile.htm |archive-date=September 28, 2006 |publisher=Agricultural Marketing Resource Center}} Alan Mitchell comments "The Americans call it 'English Walnut', which is plainly an error by the early settlers when finding the Black Walnut and Butternut growing in their woods, and 'Persian Walnut', which is correct", and Walter Fox Allen stated in his 1912 treatise What You Need to Know About Planting, Cultivating and Harvesting this Most Delicious of Nuts:{{cite web |author=Walter Fox Allen |title=How to grow English walnuts |url=http://walnutsweb.com/walnuts/How+to+Grow+English+Walnuts |url-status=dead |archive-url=https://web.archive.org/web/20090425100846/http://walnutsweb.com/walnuts/How%2Bto%2BGrow%2BEnglish%2BWalnuts |archive-date=April 25, 2009 |publisher=WalnutsWeb}} "In America, it has commonly been known as English walnut to distinguish it from our native species", and occasionally elsewhere.{{cite web |title=Ornamental Tree Photography - NZ Plant Pics Photography ornamental garden trees |url=http://www.nzplantpics.com/not_nz_trees.htm |url-status=dead |archive-url=https://web.archive.org/web/20130302023059/http://www.nzplantpics.com/not_nz_trees.htm |archive-date=2013-03-02 |access-date=2012-08-23 |publisher=Nzplantpics.com}} The name "Carpathian walnut" refers to a cultivar group of selected cold-tolerant strains with high quality nuts, rather than the species as a whole.

In the Chinese language, the edible, cultivated walnut is called {{lang|zh|胡桃}} (hú táo in modern standard Chinese), which means literally "Hu peach", suggesting the ancient Chinese associated the introduction of the tree into East Asia with the Hu barbarians of the regions north and northwest of China.{{citation needed|date=November 2024}} In Mexico, it is called {{lang|es|nogal de Castilla}},Juglans Regia {{in lang|es}} suggesting the Mexicans associated the introduction of the tree into Mexico with Spaniards from Castile (as opposed to the black walnuts native to North America).{{citation needed|date=August 2024}}

The Old English term wealhhnutu {{Clarify|date=March 2025|text=is a late book-name}} (Old English Vocabularies, Wright & Wulker), so the remark that the Anglo-Saxons inherited the walnut tree from the Romans does not follow from this name. Old English: walhhnutu is wealh (foreign) + hnutu (nut). Etymologically it "meant the nut of the Roman lands (Gaul and Italy) as distinguished from the native hazel" according to the Oxford English Dictionary.{{citation needed|date=August 2024}}

• Taxonomy of walnut species

{{Reflist}}

• [http://www.euforgen.org/species/juglans-regia/ Juglans regia] - information, genetic conservation units and related resources. European Forest Genetic Resources Programme
• [http://www.efloras.org/florataxon.aspx?flora_id=5&taxon_id=200006112 Flora of Pakistan: Juglans regia]

{{Nuts}}

{{commons category}}

{{Taxonbar|from=Q46871}}

{{Authority control}}

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