Acorn

The acorn is the nut of the oaks and their close relatives (genera Quercus, Notholithocarpus and Lithocarpus, in the family Fagaceae); alternatively known as glans.[1][2] It usually contains a seedling surrounded by two cotyledons (seedling leaves), enclosed in a tough shell known as the pericarp, and borne in a cup-shaped cupule.[3][2][4] Acorns are 1–6 cm (1⁄2–2 1⁄2 in) long and 0.8–4 cm (3⁄8–1 5⁄8 in) on the fat side. Acorns take between 5 and 24 months (depending on the species) to mature; see the list of Quercus species for details of oak classification, in which acorn morphology and phenology are important factors.

## Contents

* 1 Etymology
* 2 Ecology
* 2.1 Dispersal agents
* 3 Uses
* 3.1 Nutrition
* 3.2 Culinary
* 3.2.1 Use by Native Americans
* 3.3 In culture
* 3.3.1 Art
* 3.3.2 Military symbolism
* 3.3.3 Modern uses as symbol
* 4 See also
* 5 References
* 6 External links

## Etymology

The word acorn (earlier akerne, and acharn) is related to the Gothic name akran, which had the sense of "fruit of the unenclosed land".[5] The word was applied to the most important forest produce, that of the oak. Chaucer spoke of "achornes of okes" in the 14th century. By degrees, popular etymology connected the word both with "corn" and "oak-horn", and the spelling changed accordingly.[6] The current spelling (emerged c. 15th–16th century) derives from association with ac (Old English: "oak") + corn.[7] The Latin glans as found in many literature regarding it originally applies to any nut is the root of several Romance words for the acorn (the French gland, Catalan gla, Italian ghianda) cognate to Greek βάλανος,[8] which also extends to the vascular penile tip from similarity in shape.

## Ecology

Horses eating acorns. Acorns can cause painful death in equines, especially if eaten in excess. Sprouting acorn of Quercus robur

Acorns play an important role in forest ecology when oaks are plentiful or dominant in the landscape.[9] The volume of the acorn crop may vary widely, creating great abundance or great stress on the many animals dependent on acorns and the predators of those animals.[10] Acorns, along with other nuts, are termed mast.

Wildlife that consume acorns as an important part of their diets include birds, such as jays, pigeons, some ducks, and several species of woodpeckers. Small mammals that feed on acorns include mice, squirrels and several other rodents. One beetle species, Thorectes lusitanicus, also feeds on acorns.[11] Acorns have a large influence on small rodents in their habitats, as large acorn yields help rodent populations to grow.[12]

Large mammals such as pigs, bears, and deer also consume large amounts of acorns; they may constitute up to 25% of the diet of deer in the autumn.[13] In Spain, Portugal and the New Forest region of southern England, pigs are still turned loose in dehesas (large oak groves) in the autumn, to fill and fatten themselves on acorns. Heavy consumption of acorns can, on the other hand, be toxic to other animals that cannot detoxify their tannins, such as horses and cattle,[14][15] especially if eaten in excess.[16][17][18]

The larvae of some moths and weevils also live in young acorns, consuming the kernels as they develop.[19]

Acorns are attractive to animals because they are large and thus efficiently consumed or cached. Acorns are also rich in nutrients. Percentages vary from species to species, but all acorns contain large amounts of protein, carbohydrates and fats, as well as the minerals calcium, phosphorus and potassium, and the vitamin niacin. Total food energy in an acorn also varies by species, but all compare well with other wild foods and with other nuts.[20]

Acorns also contain bitter tannins, the amount varying with the species. Since tannins, which are plant polyphenols, interfere with an animal's ability to metabolize protein, creatures must adapt in different ways to use the nutritional value acorns contain. Animals may preferentially select acorns that contain fewer tannins. When the tannins are metabolized in cattle, the tannic acid produced can cause ulceration and kidney failure.[15]

Animals that cache acorns, such as jays and squirrels, may wait to consume some of these acorns until sufficient groundwater has percolated through them to leach out the tannins. Other animals buffer their acorn diet with other foods. Many insects, birds, and mammals metabolize tannins with fewer ill effects than do humans.

Species of acorn that contain large amounts of tannins are very bitter, astringent, and potentially irritating if eaten raw. This is particularly true of the acorns of American red oaks and English oaks. The acorns of white oaks, being much lower in tannins, are nutty in flavor; this characteristic is enhanced if the acorns are given a light roast before grinding.

Tannins can be removed by soaking chopped acorns in several changes of water, until the water no longer turns brown. Cold water leaching can take several days, but three to four changes of boiling water can leach the tannins in under an hour.[21] Hot water leaching (boiling) cooks the starch of the acorn, which would otherwise act like gluten in flour, helping it bind to itself. For this reason, if the acorns will be used to make flour, then cold water leaching is preferred.[22]

Being rich in fat, acorn flour can spoil or molder easily and must be carefully stored. Acorns are also sometimes prepared as a massage oil.

Acorns of the white oak group, Leucobalanus, typically start rooting as soon as they are in contact with the soil (in the fall), then send up the leaf shoot in the spring.

### Dispersal agents

Acorns are too heavy for wind dispersal, so they require other ways to spread. Oaks therefore depend on biological seed dispersal agents to move the acorns beyond the mother tree and into a suitable area for germination (including access to adequate water, sunlight and soil nutrients), ideally a minimum of 20–30 m (70–100 ft) from the parent tree. Many animals eat unripe acorns on the tree or ripe acorns from the ground, with no reproductive benefit to the oak, but some animals, such as squirrels and jays serve as seed dispersal agents. Jays and squirrels that scatter-hoard acorns in caches for future use effectively plant acorns in a variety of locations in which it is possible for them to germinate and thrive.

Even though jays and squirrels retain remarkably large mental maps of cache locations and return to eat them, the odd acorn may be lost, or a jay or squirrel may die before consuming all of its stores. A small number of acorns manage to germinate and survive, producing the next generation of oaks.

Scatter-hoarding behavior depends on jays and squirrels associating with plants that provide good packets of food that are nutritionally valuable, but not too big for the dispersal agent to handle. The beak sizes of jays determine how large acorns may get before jays ignore them.

Acorns germinate on different schedules, depending on their place in the oak family. Once acorns sprout, they are less nutritious, as the seed tissue converts to the indigestible lignins that form the root.[23]

Acorn, rawNutritional value per 100 g (3.5 oz)

Energy| 1,619 kJ (387 kcal)

Carbohydrates

40.75 g

Fat

23.85 g

Saturated| 3.102 g
Monounsaturated| 15.109 g
Polyunsaturated| 4.596 g

Protein

6.15 g

Tryptophan| 0.074 g
Threonine| 0.236 g
Isoleucine| 0.285 g
Leucine| 0.489 g
Lysine| 0.384 g
Methionine| 0.103 g
Cystine| 0.109 g
Phenylalanine| 0.269 g
Tyrosine| 0.187 g
Valine| 0.345 g
Arginine| 0.473 g
Histidine| 0.170 g
Alanine| 0.350 g
Aspartic acid| 0.635 g
Glutamic acid| 0.986 g
Glycine| 0.285 g
Proline| 0.246 g
Serine| 0.261 g
Vitamins| Quantity %DV†
Vitamin A equiv.|

2 μg
Thiamine (B1)|

10%

0.112 mg
Riboflavin (B2)|

10%

0.118 mg
Niacin (B3)|

12%

1.827 mg
Pantothenic acid (B5)|

14%

0.715 mg
Vitamin B6|

41%

0.528 mg
Folate (B9)|

22%

87 μg
Vitamin C|

0.0 mg
Minerals| Quantity %DV†
Calcium|

41 mg
Copper|

31%

.621 mg
Iron|

0.79 mg
Magnesium|

17%

62 mg
Manganese|

64%

1.337 mg
Phosphorus|

11%

79 mg
Potassium|

11%

539 mg
Sodium|

0 mg
Zinc|

0.51 mg
Other constituents| Quantity
Water| 27.9 g

* * *

Link to USDA Database entry

* Units
* μg = micrograms • mg = milligrams
* IU = International units

†Percentages are roughly approximated using US recommendations for adults.

## Uses

Water with acorn boiling in a pot, Kimotong, South Sudan

In some cultures, acorns once constituted a dietary staple, though they have largely been replaced by grains and are now typically considered a relatively unimportant food, except in some Native American and Korean communities.

Several cultures have devised traditional acorn-leaching methods, sometimes involving specialized tools, that were traditionally passed on to their children by word of mouth.[24][25]

### Nutrition

Raw acorns are 28% water, 41% carbohydrates, 24% fat, and 6% protein (table). In a reference amount of 100 g (3.5 oz), raw acorns supply 387 calories and are a rich source (20% or more of the Daily Value, DV) of vitamin B6, folate, copper, and manganese (table).

### Culinary

| Wikibooks Cookbook has a recipe/module on

* Acorn

|

Dotori-muk, a Korean dish made with acorn starch

Acorns served an important role in early human history and were a source of food for many cultures around the world.[26] Dental microwear suggests that Neanderthals in Belgium consumed acorns among other hard foods.[27] Many modern human cultures relied on acorns,[26] such as the Ancient Greek lower classes and the Japanese (during the Jōmon period), for instance.[28] In antiquity, Pliny the Elder noted that acorn flour could be used to make bread.[29]

Acorns rarely form a large part of modern diets and are not currently cultivated on scales approaching that of many other nuts. However, if properly prepared (by selecting high-quality specimens and leaching out the bitter tannins in water), acorn meal can be used in some recipes calling for grain flours. Varieties of oak differ in the amount of tannin in their acorns. Varieties preferred by Native Americans, such as Quercus kelloggii (California black oak), may be easier to prepare or more palatable.[30]

Roasted acorn flour is a main ingredient in sweet cakes special to Kurdish areas of Iran and Iraq.[31][32]

#### Use by Native Americans

Acorns are a traditional food of many indigenous peoples of North America, and long served an especially important role for Californian Native Americans, where the ranges of several species of oaks overlap, increasing the reliability of the resource.[33] One ecology researcher of Yurok and Karuk heritage reports that "his traditional acorn preparation is a simple soup, cooked with hot stones directly in a basket," and says he enjoys acorns eaten with "grilled salmon, huckleberries or seaweed."[34]

In the San Francisco Bay Area acorns found were often associated with grinding tools. Stone tools like hammerstone and anvil, millingstones, and mortar and pestle help crack open the acorn and grind the acorn into dust.[35]

* Mortar holes for pounding acorns into flour, Lost Lake, California

* Chuckachancy women pause in their work preparing acorns for grinding, California, c. 1920

### In culture

Campaign hat worn by General Sherman

Acorns and balanophagy (acorn-eating [fr]) were associated with ideas of primitive life and Arcadia in classical literature and beyond.[36][37][38]

#### Art

A motif in Roman architecture, also popular in Celtic and Scandinavian art, the acorn symbol is used as an ornament on cutlery, furniture, and jewelry; it also appears on finials at Westminster Abbey.

#### Military symbolism

The acorn was used frequently by both Union and Confederate forces during the American Civil War.[39] Modern US Army Cavalry Scout campaign hats still retain traces of the acorn today.

#### Modern uses as symbol

The acorn is the symbol for the National Trails of England and Wales, and is used for the waymarks on these paths.[40] The acorn, specifically that of the white oak, is also present in the symbol for the University of Connecticut.[41]

Acorns are also used as charges in heraldry.

* Acorn waymark for National Trails in England and Wales

* Acorn in the coat of arms of the du Quesne family

* Oak branch with two acorns in the coat of arms of Tammela

## See also

* Knopper gall
* Dotori-muk

## References

1. ↑ Short, Emma; George, Alex S. (2013). A primer of botanical Latin with vocabulary. Cambridge: Cambridge University Press. pp. 117, 200. ISBN 978-1-107-69375-3.
2. ↑ 2.0 2.1 Bewley, J. Derek; Black, Michael; Halmer, Peter (2006). "glans" (in en). The Encyclopedia of Seeds: Science, Technology and Uses. CABI. p. 295. ISBN 978-0-85199-723-0.
3. ↑ Dietland Müller-Schwarze (2009). Hands-On Chemical Ecology:: Simple Field and Laboratory Exercises. Springer Science & Business Media. p. 32. ISBN 978-1-4419-0378-5. https://books.google.com/books?id=WYPfQo9lUzoC&pg=PA32.
4. ↑ "Acorn | Definition & Facts". Encyclopedia Britannica. https://www.britannica.com/science/acorn-nut. Retrieved 28 April 2024.
5. ↑ Harper, Douglas. "acorn". Online Etymology Dictionary. https://www.etymonline.com/?term=acorn.
6. ↑ One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed (1911). "Acorn". Encyclopædia Britannica. 1 (11th ed.). Cambridge University Press. pp. 152–153. This cites the New English Dictionary, now the Oxford English Dictionary
7. ↑ "Online Etymology Dictionary" (in en). http://www.etymonline.com/index.php?allowed_in_frame=0&search=acorn&searchmode=none.
8. ↑ Emerson, George Barrell (1894) (in en). A report on the trees and shrubs growing naturally in the forests of Massachusetts. I. Little, Brown. p. 132. https://www.google.com/books/edition/Containing_the_pines_oaks_beech_chestnut/YQQmAQAAMAAJ?hl=en&gbpv=1&dq=glans+βάλανος+date&pg=PA132&printsec=frontcover.
9. ↑ Plumb, Timothy R., ed (1980). Proceedings of the symposium on the ecology, management, and utilization of California oaks, June 26–28. USDA Forest Service General Technical Report PSW-044. pp. 1 to 368. http://www.fs.fed.us/psw/publications/documents/psw_gtr044/psw_gtr044.pdf.
10. ↑ King, Richie S. (2 December 2011). "After Lean Acorn Crop in Northeast, Even People May Feel the Effects". The New York Times. https://www.nytimes.com/2011/12/03/nyregion/boom-and-bust-in-acorns-will-affect-many-creatures-including-humans.html. "there is nothing unusual about large fluctuations in the annual number of acorns."
11. ↑ PéRez-Ramos, Ignacio M.; MarañóN, Teodoro; Lobo, Jorge M.; Verdú, José R. (August 2007). "Acorn removal and dispersal by the dung beetle Thorectes lusitanicus : ecological implications" (in en). Ecological Entomology 32 (4): 349–356. doi:10.1111/j.1365-2311.2007.00874.x. ISSN 0307-6946. Bibcode: 2007EcoEn..32..349P. https://resjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2311.2007.00874.x.
12. ↑ "Acorn Study | Research | Upland Hardwood Ecology and Management | SRS". https://www.srs.fs.usda.gov/uplandhardwood/research/article/acorn-study.
13. ↑ Barrett, Reginald H. (1980). "Mammals of California Oak Habitats-Management Implications". in Plumb, Timothy R.. Proceedings of the symposium on the ecology, management, and utilization of California oaks, June 26–28. USDA Forest Service General Technical Report PSW-044. pp. 276–291. http://www.fs.fed.us/psw/publications/documents/psw_gtr044/psw_gtr044.pdf.
14. ↑ "A bumper crop of acorns causes concern for those with horses". Immediate Media Company. 19 October 2011. http://www.countryfile.com/news/bumper-crop-acorns-causes-concern-those-horses.
15. ↑ 15.0 15.1 Barringer, Sam. "Acorns Can be Deadly". http://www.caf.wvu.edu/~forage/acorns/acorns.htm.
16. ↑ Nz, Horsetalk. co (2013-11-27). "Acorns fatally poison 50 ponies in English forest". Horsetalk.co.nz. http://horsetalk.co.nz/2013/11/23/acorns-fatally-poison-50-ponies-english-forest/#axzz40efTYqgN.
17. ↑ "Acorn Poisoning – Are Acorns Poisonous To Horses?". Horse-advice.com. http://www.horse-advice.com/equestrian/equine-veterinary/acorns-poisonous.shtml.
18. ↑ "Acorns, Oaks and Horses: Tannin Poisoning". The Way of Horses. 2002-09-15. http://www.thewayofhorses.com/10_08_acorns.html.
19. ↑ Brown, Leland R. (1979) Insects Feeding on California Oak Treesin Proceedings of the Symposium on Multiple-Use Management of California's Hardwood Resources, Timothy Plum and Norman Pillsbury (eds.).
20. ↑ "Nutrition Facts for Acorn Flour". Nutritiondata.com. http://www.nutritiondata.com/facts-001-02s02dn.html.
21. ↑ Tull, Delena (1987). A practical guide to edible & useful plants : including recipes, harmful plants, natural dyes & textile fibers. Austin, Tex.: Texas Monthly Press. ISBN 9780877190226. OCLC 15015652.
22. ↑ "Two Ways to Make Cold Leached Acorn Flour – Learn How with this Guide". The Spruce. https://www.thespruce.com/cold-leaching-and-preserving-acorn-flour-4007438.
23. ↑ Janzen, Daniel H. (1971), Richard F. Johnson, Peter W. Frank and Charles Michner, ed., "Seed Predation by Animals", Annual Review of Ecology and Systematics 2 (1): 465–492, doi:10.1146/annurev.es.02.110171.002341, Bibcode: 1971AnRES...2..465J
24. ↑ "Indigenous Food and Traditional Recipes". NativeTech. http://www.nativetech.org/recipes/recipe.php?recipeid=115.
25. ↑ "Cooking With Acorns". Siouxme.com. http://www.siouxme.com/acorn.html.
26. ↑ 26.0 26.1 Bainbridge, D. A. (12–14 November 1986), Use of acorns for food in California: past, present and future, San Luis Obispo, CA.: Symposium on Multiple-use Management of California's Hardwoods, http://www.ecocomposite.org/native/UseOfAcornsForFoodInCalifornia.doc, retrieved 1 September 2010
27. ↑ Williams, Frank L’Engle; Schmidt, Christopher W.; Droke, Jessica L.; Willman, John C.; Semal, Patrick; Becam, Gaël; de Lumley, Marie-Antoinette (December 2019). "Dietary reconstruction of Spy I using dental microwear texture analysis" (in en). Comptes Rendus Palevol 18 (8): 1083–1094. doi:10.1016/j.crpv.2019.06.004. Bibcode: 2019CRPal..18.1083W. https://www.sciencedirect.com/science/article/pii/S1631068319301277. Retrieved 16 November 2025.
28. ↑ Junko Habu; Habu Junko (29 July 2004). Ancient Jomon of Japan. Cambridge University Press. ISBN 978-0-521-77670-7. https://books.google.com/books?id=vGnAbTyTynsC.
29. ↑ Alphonso, Christina (5 November 2015). "Acres of Acorns". http://www.metmuseum.org/blogs/in-season/2015/acres-of-acorns.
30. ↑ Derby, Jeanine A. (1980). "Acorns-Food for Modern Man". in Plumb, Timothy R.. Proceedings of the symposium on the ecology, management, and utilization of California oaks, June 26–28. USDA Forest Service General Technical Report PSW-044. pp. 360–361. http://www.fs.fed.us/psw/publications/documents/psw_gtr044/psw_gtr044.pdf.
31. ↑ Hooper, David; Field, Henry (1937). Plants and Drugs of Iran and Iraq. Field Museum of Natural History. p. 161.
32. ↑ Salih, Rafiq Mohamed; Sabir, Dlir Amin; Hawramee, Othman K. (October 2013). "Effect of sweet acorn flour of common oak (Quercus aegilops L.) on locally Iraqi pastry (kulicha) products". Journal of Zankoy Sulaimani - Part A 16 (special): 244–249. doi:10.17656/jzs.10327.
33. ↑ Suttles, Wayne (1964), "(Review of) Ecological Determinants of Aboriginal California Populations, by Martin A. Baumhoff", American Anthropologist 66 (3): pp. 676, doi:10.1525/aa.1964.66.3.02a00360
34. ↑ Prichep, Deena (2014-11-02). "Nutritious Acorns Don't Have To Just Be Snacks For Squirrels". https://www.npr.org/blogs/thesalt/2014/10/24/358527018/nutritious-acorns-dont-have-to-just-be-snacks-for-squirrels.
35. ↑ Buonasera, T.Y. (2013). More than acorns and small seeds: A diachronic analysis of mortuary-associated ground stone from the south San Francisco Bay area. Journal of Anthropological Archaeology, 32(2), 190–211. https://doi.org/10.1016/j.jaa.2013.01.003
36. ↑ Levine, Daniel B. (1989). "Acorns and Primitive Life in Greek and Latin Literature". Classical and Modern Literature [Wikidata] 9 (2): 87–95. https://www.academia.edu/2373310.
37. ↑ Mason, Sarah Louise Rhoda (1995). "Acornutopia? Determining the role of acorns in past human subsistence". in Wilkins, John; Harvey, David; Dobson, Mike. Food in Antiquity. University of Exeter Press. pp. 12–24.
38. ↑ Vaughan, Geoffrey M. (2025). ""The Loathing of the Acorn": On the Role of Food and Taste in the State of Nature". Perspectives on Political Science 54: 237–247. doi:10.1080/10457097.2025.2533427. https://www.tandfonline.com/doi/abs/10.1080/10457097.2025.2533427.
39. ↑ "Chikamauga and Chattanooga". U.S. Forest Service. 2022-10-27. https://www.nps.gov/chch/faqs.htm.
40. ↑ "National Trail Acorn". http://www.nationaltrail.co.uk/hadrianswall/publications.asp?PageId=276.
41. ↑ "University of Connecticut". http://uconn.edu/.

## External links

* Acorn at the Wikibooks Cookbook subproject

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Nuts

True, or botanical nuts|

* Acorn
* Beech
* American beech
* European beech
* Breadnut
* Candlenut
* Chestnut
* Sweet chestnut
* Hazelnut
* American hazel
* Beaked hazel
* European hazel
* Filbert
* Asian hazel
* Johnstone River almond
* Kola nut
* Kurrajong
* Malabar chestnut
* Palm nut
* Red bopple nut
* Yellow walnut

Drupes|

* Almond
* Australian cashew nut
* Betel nut
* Borneo tallow nut
* Breadfruit
* Cashew
* Chilean hazel
* Coconut
* Durian
* Gabon nut
* Hickory
* Mockernut hickory
* Pecan
* Shagbark hickory
* Shellbark hickory
* Irvingia gabonensis
* Jack nut
* Karuka
* Planted karuka
* Wild karuka
* Mongongo
* Panda oleosa
* Pekea nut
* Pili nut
* Pistachio
* Walnut
* Black walnut
* Butternut
* English walnut
* Heartnut

Gymnosperms|

* Cycad
* Burrawang nut
* Ginkgo nut
* Araucaria spp.
* Bunya nut
* Monkey-puzzle nut
* Pine nut
* Chilgoza pine
* Colorado pinyon
* Korean pine
* Mexican pinyon
* Single-leaf pinyon
* Stone pine

Angiosperms|

* Brazil nut
* Macadamia
* Macadamia nut
* Queensland macadamia nut
* Paradise nut
* Peanut
* Peanut tree
* Soybean

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