![Oak apples - Keila](https://upload.wikimedia.org/wikipedia/commons/d/d8/Oak_apples_-_Keila.jpg)
Oak apple or oak gall is the common name for a large, round, vaguely apple-like
gall
Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissues, similar to be ...
commonly found on many species of
oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
. Oak apples range in size from in diameter and are caused by chemicals injected by the
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
of certain kinds of
gall wasp
Gall wasps, also incorrectly called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this generall ...
in the family Cynipidae.
The adult female wasp lays single eggs in developing leaf
bud
In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be spec ...
s. The wasp larvae feed on the gall
tissue resulting from their
secretion 440px
Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. The classical ...
s, which modify the oak bud into the gall, a structure that protects the developing larvae until they undergo
metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...
into adults.
Considerable confusion exists in the general literature between the oak apple and the
oak marble gall
''Andricus kollari'', also known as the marble gall wasp, is a parthenogenetic species of wasp which causes the formation of marble galls on oak trees. Synonyms for the species include ''Cynips kollari'', ''Andricus quercusgemmae'', ''A. minor'', ...
. The oak marble is frequently called the oak apple due to the superficial resemblance and the preponderance of the oak marble gall in the wild. Other galls found on oak trees include the
oak artichoke gall
Andricus foecundatrix (formerly ''Andricus fecundator'') is a parthenogenetic gall wasp which lays a single egg within a leaf bud, using its ovipositor, to produce a gall known as an oak artichoke gall, oak hop gall, larch-cone gall or hop strobi ...
and the
acorn cup gall, but each of these has its own distinctive form.
Some common oak-apple-forming species are the ''
Biorhiza pallida'' gall wasp in Europe, ''
Amphibolips confluenta'' in eastern North America, and ''Atrusca bella'' in western North America.
Oak apples may be brownish, yellowish, greenish, pinkish, or reddish.
Iron gall ink
Oak galls have been used in the production of ink since at least the time of the
Roman Empire
The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterr ...
. From the
Middle Ages
In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
to the early twentieth century, iron gall ink was the main medium used for writing in the Western world.
Gall nuts are a source of
tannin
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.
The term ''tannin'' (from Anglo-Norman ''tanner'', ...
in the production of iron gall ink. Tannins belong to a group of molecules known as polyphenols and can be taken from different parts of plants such as leaves, pods, fruits, and gall nuts.
Along with gall nuts, other important ingredients in the production of iron gall ink include
iron sulfate Iron sulfate may refer to:
* Ferrous sulfate, Iron(II) sulfate
Iron(II) sulfate (British English: iron(II) sulphate) or ferrous sulfate denotes a range of salts with the formula Fe SO4·''x''H2O. These compounds exist most commonly as the hept ...
and
gum arabic
Gum arabic, also known as gum sudani, acacia gum, Arabic gum, gum acacia, acacia, Senegal gum, Indian gum, and by other names, is a natural gum originally consisting of the hardened sap of two species of the '' Acacia'' tree, ''Senegalia sen ...
. The reaction between the tannins from the gall nut and the iron produces a complex that gives the iron gall ink its color. The gum arabic makes the ink more viscous and helps bind the ink to the writing surface.
Folklore
It is said that if a "worm" is found inside the gall on
Michaelmas Day
Michaelmas ( ; also known as the Feast of Saints Michael, Gabriel, and Raphael, the Feast of the Archangels, or the Feast of Saint Michael and All Angels) is a Christianity, Christian festival observed in some Western liturgical year, liturgica ...
, then the year will be pleasant and unexceptional, and if a spider is found, then it will be a bad year with shortages and ruined crops. If a fly is found inside, then it will be a moderate season, and if nothing is found, then serious diseases will occur all that year.
[Roud, Steven (2003). ''The Penguin Guide to the Superstitions of Britain and Ireland''. Pengun Books. p. 344.]
Oak Apple Day
Restoration Day, more commonly known as Oak Apple Day or Royal Oak Day, was an English, Welsh and Irish public holiday, observed annually on 29 May, to commemorate the restoration of the Stuart monarchy in May 1660. In some parts of England the ...
(or Royal Oak Day) is a former public holiday in
England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
on 29 May that commemorated the
Restoration
Restoration is the act of restoring something to its original state and may refer to:
* Conservation and restoration of cultural heritage
** Audio restoration
** Film restoration
** Image restoration
** Textile restoration
* Restoration ecology
...
of
Charles II in 1660. The popular name refers to the event during the
English Civil War
The English Civil War (1642–1651) was a series of civil wars and political machinations between Parliamentarians (" Roundheads") and Royalists led by Charles I ("Cavaliers"), mainly over the manner of England's governance and issues of re ...
when Charles hid in an
oak tree
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably '' ...
. The commemoration persists in some areas today, although festivities have little to do with the Restoration.
Gallery
File:Oak apple BW 2014-11-16 20-35-06.jpg, An oak apple on an oak leaf.
Image:Oak apple Wiltshire October 2007.JPG, Oak apples on the undersides of oak leaves
File:Oakgall3800ppx.JPG, An oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
tree with multiple oak apples.
Image:Oak Gall.jpg, ''Andricus kollari'' oak gall
File:Galle.jpg, Oak apples on an oak tree.
File:Gallrazorback.jpg, Oak apple gall on Garry oak (''Quercus garryana
''Quercus garryana'' is an oak tree species of the Pacific Northwest, with a range stretching from southern California to southwestern British Columbia. It is commonly known as the Oregon white oak or Oregon oak or, in Canada, the Garry oak. It ...
'')
File:Oak apples on oak leaf and in cross section.JPG, Oak apples on oak leaf and in cross section
File:Biorhiza pallida male.jpg, '' Biorhiza pallida'' male
See also
*
Knopper gall
''Andricus quercuscalicis'' is a gall wasp species inducing knopper galls.
Knopper galls develop as a chemically induced distortion of growing acorns on pedunculate oak (''Quercus robur'' L.) trees, caused by gall wasps, which lay eggs in buds w ...
*
Oak Apple Day
Restoration Day, more commonly known as Oak Apple Day or Royal Oak Day, was an English, Welsh and Irish public holiday, observed annually on 29 May, to commemorate the restoration of the Stuart monarchy in May 1660. In some parts of England the ...
*
Pineapple gall
The Pineapple gall adelgid (''Adelges abietis'') is a type of conifer-feeding insect that forms pineapple-shaped plant galls on its host species, commonly Norway and Sitka spruce. The adelgids (genus ''Adelges'') are pear-shaped, soft-bodied gr ...
References
External links
Amphibolips confluentaBiorhiza pallidaGloucestershire Naturalists' Society photograph of galls with 'red apple' appearanceSee also
The Oak Apple Gall
{{DEFAULTSORT:Oak Apple
Cynipoidea
Oak galls