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''Macadamia'' is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of four
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of trees in the
flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
family
Proteaceae The Proteaceae form a family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genera with about 1,660 known species. Together with the Platanaceae and Nelumbonaceae, they make up the order Pro ...
. They are indigenous to Australia, native to northeastern
New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...
and central and southeastern
Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...
specifically. Two species of the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
are commercially important for their fruit, the macadamia nut (or simply macadamia). Global production in 2015 was . Other names include Queensland nut, bush nut, maroochi nut, bauple nut and Hawaii nut. In
Australian Aboriginal languages The Indigenous languages of Australia number in the hundreds, the precise number being quite uncertain, although there is a range of estimates from a minimum of around 250 (using the technical definition of 'language' as non-mutually intellig ...
, the fruit is known by names such as ''bauple'', ''gyndl'' or ''jindilli'' (north of
Great Dividing Range The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills, that runs rough ...
) and ''boombera'' (south of the Great Range). It was an important source of
bushfood Bush tucker, also called bush food, is any food native to Australia and used as sustenance by Indigenous Australians, the Aboriginal and Torres Strait Islander peoples, but it can also describe any native flora or fauna used for culinary or ...
for the
Aboriginal peoples Indigenous peoples are culturally distinct ethnic groups whose members are directly descended from the earliest known inhabitants of a particular geographic region and, to some extent, maintain the language and culture of those original people ...
who are the original inhabitants of the area. The nut was first commercially produced on a wide scale in
Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
, where Australian seeds were introduced in the 1880s, and for some time, they were the world's largest producer. South Africa has been the world's largest producer of the macadamia since the 2010s.


Etymology

The German-Australian
botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...
Ferdinand von Mueller Baron Sir Ferdinand Jacob Heinrich von Mueller, (german: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Vict ...
gave the genus the name ''Macadamia'' in 1857 in honour of the Scottish-Australian
chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe th ...
, medical teacher, and
politician A politician is a person active in party politics, or a person holding or seeking an elected office in government. Politicians propose, support, reject and create laws that govern the land and by an extension of its people. Broadly speaking, a ...
John Macadam The Honorable Dr John Macadam (29 May 1827 – 2 September 1865), was a Scottish- Australian chemist, medical teacher, Australian politician and cabinet minister, and honorary secretary of the Burke and Wills expedition. The genus ''Macadamia ...
, who was the honorary Secretary of the
Philosophical Institute of Victoria The Philosophical Institute of Victoria was a scientific institute functioned in Victoria, Australia during 19th century. It was founded in 1854 through the amalgamation of the Victorian Institute for the Advancement of Science and the Philosophica ...
beginning in 1857.


Description

''Macadamia'' is an
evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
that grows tall. The leaves are arranged in
whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ...
s of three to six,
lanceolate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...
to
obovate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...
or
elliptic In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. It generalizes a circle, which is the special type of ellipse in ...
in
shape A shape or figure is a graphics, graphical representation of an object or its external boundary, outline, or external Surface (mathematics), surface, as opposed to other properties such as color, Surface texture, texture, or material type. A pl ...
, long and broad, with an entire or spiny-serrated margin. The flowers are produced in a long, slender, and simple
raceme A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...
long, the individual flowers long, white to pink or purple, with four
tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...
s. The fruit is a hard, woody, globose follicle with a pointed apex containing one or two
seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s. The nutshell ("coat") is particularly tough and requires around 2000 N to crack. The shell material is five times harder than
hazelnut The hazelnut is the fruit of the hazel tree and therefore includes any of the nuts deriving from species of the genus ''Corylus'', especially the nuts of the species ''Corylus avellana''. They are also known as cobnuts or filberts according t ...
shells and has mechanical properties similar to
aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
. It has a
Vickers hardness The Vickers hardness test was developed in 1921 by Robert L. Smith and George E. Sandland at Vickers Ltd as an alternative to the Brinell method to measure the hardness of materials. The Vickers test is often easier to use than other hardness t ...
of 35.


Modern history

;1828 : Allan Cunningham was the first European to encounter the macadamia plant in Australia. ;1857 - 1858 :German-Australian botanist
Ferdinand von Mueller Baron Sir Ferdinand Jacob Heinrich von Mueller, (german: Müller; 30 June 1825 – 10 October 1896) was a German-Australian physician, geographer, and most notably, a botanist. He was appointed government botanist for the then colony of Vict ...
gave the genus the scientific name ''Macadamia''. He named it after his friend John Macadam, a noted scientist and secretary of the Philosophical Institute of Australia. ;1858 :'Bauple nuts' were discovered in Bauple, Queensland; they are now known as macadamia nuts. :
Walter Hill Walter may refer to: People * Walter (name), both a surname and a given name * Little Walter, American blues harmonica player Marion Walter Jacobs (1930–1968) * Gunther (wrestler), Austrian professional wrestler and trainer Walter Hahn (born 19 ...
, superintendent of the Brisbane Botanic Gardens (Australia), observed a boy eating the kernel without ill effect, becoming the first nonindigenous person recorded to eat macadamia nuts. ;1860s :King Jacky, aboriginal elder of the Logan River clan, south of Brisbane, Queensland, was the first known macadamia entrepreneur in his tribe and he regularly collected and traded the macadamias with settlers. ;1866 : Tom Petrie planted macadamias at Yebri Creek (near Petrie) from nuts obtained from Aboriginals at Buderim. ;1882 :
William H. Purvis William Herbert Purvis (November 27, 1858 – December 31, 1950) was a plant collector and investor in a sugarcane Sugar plantations in Hawaii, plantation on the Hawaii (island), island of Hawaii during the late nineteenth century. William He ...
introduced macadamia nuts to Hawaii as a
windbreak A windbreak (shelterbelt) is a planting usually made up of one or more rows of trees or shrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion. They are commonly planted in hedgerows around the edges ...
for sugar cane. ;1888 :The first commercial orchard of macadamias was planted at Rous Mill, 12 km from
Lismore, New South Wales Lismore is a city in northeastern New South Wales, Australia and the main population centre in the City of Lismore Local government in Australia, local government area; it is also a regional centre in the Northern Rivers region of the State. It ...
, by Charles Staff. ;1889 :
Joseph Maiden Joseph Henry Maiden (25 April 1859 – 16 November 1925) was a botanist who made a major contribution to knowledge of the Australian flora, especially the genus ''Eucalyptus''. This botanist is denoted by the author abbreviation when citing ...
, an Australian botanist, wrote, "It is well worth extensive cultivation, for the nuts are always eagerly bought." ;1910 :The Hawaiian Agricultural Experiment Station encouraged the planting of macadamias on Hawaii's
Kona District Kona is a ''moku'' or district on the Big Island of Hawaii in the State of Hawaii, known for its Kona coffee and the location of the Ironman World Championship Triathlon. In the current system of administration of Hawaii County, the ''moku'' o ...
as a crop to supplement coffee production in the region.Rieger, M., ''Introduction to Fruit Crops'', 2006, p. 260. ;1916 : Tom Petrie begins trial macadamia plantations in
Maryborough, Queensland Maryborough ( ) is a city and a suburb in the Fraser Coast Region, Queensland, Australia. At the 2021 Census, Maryborough had a population of 15,287. Geography Maryborough is located on the Mary River in Queensland, Australia, approximate ...
, combining macadamias with pecans to shelter the trees. ;1922 :Ernest van Tassel formed the Hawaiian Macadamia Nut Co. in Hawaii. ;1925 :Tassel leased on Round Top in Honolulu and began Nutridge, Hawaii's first macadamia seed farm. ;1931 :Tassel established a macadamia-processing factory on Puhukaina Street in Kakaako, Hawaii, selling the nuts as Van's Macadamia Nuts. ;1937 :Winston Jones and J. H. Beaumont of the University of Hawaii's Agricultural Experiment Station reported the first successful grafting of macadamias, paving the way for mass production. ;1946 :A large plantation was established in Hawaii. ;1953 :
Castle & Cooke Castle & Cooke, Inc., is a Los Angeles-based company that was once part of the Big Five companies in territorial Hawaii. The company at one time did most of its business in agriculture, including becoming, through mergers with the modern Dole F ...
added a new brand of macadamia nuts called "Royal Hawaiian," which was credited with popularizing the nuts in the U.S. ;1991 :A fourth macadamia species, ''
Macadamia jansenii ''Macadamia jansenii'' is an endangered and poisonous tree in the flowering plant family Proteaceae, native to Queensland in Australia. It was only described as a new species in 1991, being first brought to the attention of plant scientists in ...
'', was described, being first brought to the attention of plant scientists in 1983 by Ray Jansen, a sugarcane farmer and amateur botanist from
South Kolan South Kolan is a rural locality in the Bundaberg Region, Queensland, Australia. In the , South Kolan had a population of 1,061 people. Geography The South Kolan region is in the Wide Bay–Burnett region, north of the state capital Brisbane an ...
in Central
Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...
. ;1997 :Australia surpassed the United States as the major producer of macadamias. ;2012–2015 :South Africa surpassed Australia as the largest producer of macadamias. ;2014 :The manner in which macadamia nuts were served on
Korean Air Korean Air Co., Ltd. (), operating as Korean Air (Korean Air Lines before 1984), is the flag carrier of South Korea and its largest airline based on fleet size, international destinations and international flights. The present-day Korean Air ...
Flight 86 from
John F. Kennedy International Airport John F. Kennedy International Airport (colloquially referred to as JFK Airport, Kennedy Airport, New York-JFK, or simply JFK) is the main international airport serving New York City. The airport is the busiest of the seven airports in the Avia ...
in
New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...
led to a " nut rage incident", which gave the nuts high visibility in
South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
and marked a sharp increase in consumption there.


Species

* ''
Macadamia integrifolia ''Macadamia integrifolia'' is a small to medium-sized tree, growing to 15 metres in height. Native to rainforests in south east Queensland and northern New South Wales, Australia. Common names include macadamia, smooth-shelled macadamia, bush n ...
'' * ''
Macadamia jansenii ''Macadamia jansenii'' is an endangered and poisonous tree in the flowering plant family Proteaceae, native to Queensland in Australia. It was only described as a new species in 1991, being first brought to the attention of plant scientists in ...
'' * ''
Macadamia ternifolia ''Macadamia ternifolia'' (common names: small-fruited Queensland nut, gympie nut) is a tree in the flowering plant family Proteaceae, native to Queensland in Australia, and is listed as vulnerable under the EPBC Act. ''Macadamia ternifolia'' is ...
'' * ''
Macadamia tetraphylla ''Macadamia tetraphylla'' is a tree in the family Proteaceae, native to southern Queensland and northern New South Wales in Australia. Common names include macadamia nut, bauple nut, prickly macadamia, Queensland nut, rough-shelled bush nut ...
'' Nuts from ''M. jansenii'' and M. ternifolia contain
cyanogenic glycosides In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosi ...
. The other two species are cultivated for the commercial production of macadamia nuts for human consumption. Previously, more species with
disjunct distribution In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but considerably separated from each other geographically. The causes are varied and might demonstrate either the expansion or contraction of a s ...
s were named as members of this genus ''Macadamia''. Genetics and morphological studies published in 2008 show they have separated from the genus ''Macadamia'', correlating less closely than thought from earlier morphological studies. The species previously named in the genus ''Macadamia'' may still be referred to overall by the descriptive, non-scientific name of macadamia. ;Formerly included in the genus: ;''
Lasjia ''Lasjia'' is a genus of five species of trees of the family Proteaceae. Three species grow naturally in northeastern Queensland, Australia and two species in Sulawesi, Indonesia. Descriptively they are the tropical or northern macadamia trees gr ...
'' , formerly ''Macadamia'' until 2008 * ''
Lasjia claudiensis ''Lasjia claudiensis'' is a species of tree in the protea family that is endemic to the Cape York Peninsula of Far North Queensland in north-eastern Australia. It is listed as Vulnerable under Queensland's Nature Conservation Act 1992 as well ...
'' ; synonym, base name: ''Macadamia claudiensis'' * ''
Lasjia erecta ''Lasjia erecta'' is a species of forest tree in the protea family that is endemic to the island of Sulawesi, Indonesia. Its closest relative is '' Lasjia hildebrandii'', also a Sulawesi endemic. History The tree was first described in 1995 ...
'' ; synonym, base name: ''Macadamia erecta''
A tree
endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to the island of
Sulawesi Sulawesi (), also known as Celebes (), is an island in Indonesia. One of the four Greater Sunda Islands, and the world's eleventh-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Mindanao and the Sulu Ar ...
, Indonesia. First described by science in 1995. * ''
Lasjia grandis ''Lasjia grandis'', also known as the satin silky oak or Barong nut, is a species of forest tree in the protea family that is endemic to north-eastern Queensland, Australia. Its conservation status is considered to be Vulnerable under Queensla ...
'' ; synonym, base name: ''Macadamia grandis'' * ''
Lasjia hildebrandii ''Lasjia hildebrandii'', also known as Celebes nut, Sulawesi nut, Sulawesi macadamia or Hildebrand's macadamia, is a species of forest tree in the protea family that is endemic to the island of Sulawesi, Indonesia. Its closest relative is ''Las ...
'' ; synonym, base name: ''Macadamia hildebrandii''
Another species endemic to Sulawesi. * ''
Lasjia whelanii ''Lasjia whelanii'', also known as Whelan's silky oak, Whelan's nut oak or Whelan's macadamia, is a species of large forest tree in the protea family that is endemic to north-eastern Queensland, Australia. History The tree was first describ ...
'' ; synonyms: base name: ''Helicia whelanii'' , ''Macadamia whelanii'' ;''
Catalepidia ''Catalepidia'' is a genus of a sole described species of medium-sized trees, constituting part of the plant family Proteaceae. The species ''Catalepidia heyana'' grows naturally only in a restricted mountain region ( endemic) of the wet trop ...
'' , formerly ''Macadamia'' until 1995 *'' Catalepidia heyana'' ; synonyms: base name: ''Helicia heyana'' , ''Macadamia heyana'' ;'' Virotia'' , formerly ''Macadamia'' until the first species renaming began in 1975 and comprehensive in 2008 *''
Virotia angustifolia ''Virotia'' is a genus of six species of flowering plants in the family Proteaceae. The genus is endemic to New Caledonia with six species that were once placed in '' Macadamia''.Virot, R. (1967). Protéacées. In Flore de La Nouvelle-Calédonie ...
'' ; synonym, base name: ''Macadamia angustifolia'' *''
Virotia francii ''Virotia'' is a genus of six species of flowering plants in the family Proteaceae. The genus is endemic to New Caledonia with six species that were once placed in '' Macadamia''.Virot, R. (1967). Protéacées. In Flore de La Nouvelle-Calédonie ...
'' ; synonym, base name: ''
Roupala ''Roupala'' is a Neotropical genus of woody shrubs and trees in the plant family Proteaceae. Its 34 species are generally found in forests from sea level to 4000 m altitude from Mexico to Argentina. Taxonomy and naming The genus was described b ...
francii'' *''
Virotia leptophylla ''Virotia'' is a genus of six species of flowering plants in the family Proteaceae. The genus is endemic to New Caledonia with six species that were once placed in '' Macadamia''.Virot, R. (1967). Protéacées. In Flore de La Nouvelle-Calédonie ...
'' (1975 type species); synonym, base name: ''
Kermadecia ''Kermadecia'' is a genus of flowering plants in the family Proteaceae. The genus comprises five species, all endemic to New Caledonia. Its closest relatives are '' Sleumerodendron'' (New Caledonia) and '' Turrillia'' (Fiji, Vanuatu Vanuatu ...
leptophylla'' *''
Virotia neurophylla ''Virotia neurophylla'' (previously ''Macadamia neurophylla'') is a species of plant in the family Proteaceae. It is endemic to New Caledonia. It is threatened by habitat loss Habitat destruction (also termed habitat loss and habitat red ...
'' ; synonyms: base name: ''
Kermadecia ''Kermadecia'' is a genus of flowering plants in the family Proteaceae. The genus comprises five species, all endemic to New Caledonia. Its closest relatives are '' Sleumerodendron'' (New Caledonia) and '' Turrillia'' (Fiji, Vanuatu Vanuatu ...
neurophylla'' , ''Macadamia neurophylla'' *''
Virotia rousselii ''Virotia'' is a genus of six species of flowering plants in the family Proteaceae. The genus is endemic to New Caledonia with six species that were once placed in '' Macadamia''.Virot, R. (1967). Protéacées. In Flore de La Nouvelle-Calédonie ...
'' ; synonym, base name: ''Roupala rousselii'' *''
Virotia vieillardi ''Virotia'' is a genus of six species of flowering plants in the family Proteaceae. The genus is endemic to New Caledonia with six species that were once placed in '' Macadamia''.Virot, R. (1967). Protéacées. In Flore de La Nouvelle-Calédonie ...
'' ; synonym, base name: ''Roupala vieillardii''


Cultivation

The macadamia tree is usually propagated by
grafting Grafting or graftage is a horticultural technique whereby tissues of plants are joined so as to continue their growth together. The upper part of the combined plant is called the scion () while the lower part is called the rootstock. The succ ...
and does not begin to produce commercial quantities of seeds until it is 7–10 years old, but once established, it may continue bearing for over 100 years. Macadamias prefer fertile, well-drained soils, a rainfall of , and temperatures not falling below (although once established, they can withstand light frosts), with an optimum temperature of . The roots are shallow, and trees can be blown down in storms; like most
Proteaceae The Proteaceae form a family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genera with about 1,660 known species. Together with the Platanaceae and Nelumbonaceae, they make up the order Pro ...
, they are also susceptible to ''
Phytophthora ''Phytophthora'' (from Greek language, Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on cro ...
'' root disease. As of 2019, the macadamia nut is the most expensive nut in the world, which is attributed to the slow harvesting process.


Cultivars


Beaumont

A ''
Macadamia integrifolia ''Macadamia integrifolia'' is a small to medium-sized tree, growing to 15 metres in height. Native to rainforests in south east Queensland and northern New South Wales, Australia. Common names include macadamia, smooth-shelled macadamia, bush n ...
'' / '' M. tetraphylla'' hybrid commercial variety is widely planted in Australia and New Zealand; Dr. J. H. Beaumont discovered it. It is high in oil but is not sweet. New leaves are reddish, and flowers are bright pink, borne on long racemes. It is one of the quickest varieties to come into bearing once planted in the garden, usually carrying a useful crop by the fourth year and improving from then on. It crops prodigiously when well pollinated. The impressive, grape-like clusters are sometimes so heavy they break the branchlets to which they are attached. Commercial orchards have reached per tree by eight years old. On the downside, the macadamias do not drop from the tree when ripe, and the leaves are a bit prickly when one reaches into the tree's interior during harvest. Its shell is easier to open than that of most commercial varieties.


Maroochy

A pure '' M. tetraphylla'' variety from Australia, this strain is cultivated for its productive crop yield, flavor, and suitability for pollinating 'Beaumont.'


Nelmac II

A South African ''M. integrifolia'' / ''M. tetraphylla'' hybrid cultivar, it has a sweet seed, which means it has to be cooked carefully so that the sugars do not caramelise. The sweet seed is usually not fully processed, as it generally does not taste as good, but many people enjoy eating it uncooked. It has an open micropyle (hole in the shell), which may let in fungal spores. The crack-out percentage (ratio of nut meat to the whole nut by weight) is high. Ten-year-old trees average per tree. It is a popular variety because of its pollination of 'Beaumont,' and the yields are almost comparable.


Renown

A ''M. integrifolia'' / ''M. tetraphylla'' hybrid, this is a rather spreading tree. On the plus side, it is high yielding commercially; from a 9-year-old tree has been recorded, and the nuts drop to the ground. However, they are thick-shelled, with not much flavor.


Production

In 2018,
South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
was estimated as the leading producer of macadamia nuts, with 54,000 tonnes out of global production of 211,000 tonnes. Macadamia is commercially produced in many countries of Southeast Asia, South America, Australia, and North America having
Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...
,
temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...
or
tropical climate Tropical climate is the first of the five major climate groups in the Köppen climate classification identified with the letter A. Tropical climates are defined by a monthly average temperature of 18 °C (64.4 °F) or higher in the cool ...
s.


History

The first commercial orchard of macadamia trees was planted in the early 1880s by Rous Mill, southeast of
Lismore, New South Wales Lismore is a city in northeastern New South Wales, Australia and the main population centre in the City of Lismore Local government in Australia, local government area; it is also a regional centre in the Northern Rivers region of the State. It ...
, consisting of '' M. tetraphylla''. Besides the development of a small boutique industry in Australia during the late 19th and early 20th centuries, macadamia was extensively planted as a commercial crop in
Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
from the 1920s onward. Macadamia seeds were first imported into Hawaii in 1882 by
William H. Purvis William Herbert Purvis (November 27, 1858 – December 31, 1950) was a plant collector and investor in a sugarcane Sugar plantations in Hawaii, plantation on the Hawaii (island), island of Hawaii during the late nineteenth century. William He ...
, who planted seeds that year at Kapulena. The Hawaiian-produced macadamia established the well-known seed internationally, and in 2017, Hawaii produced over 22,000 tonnes. In 2019, researchers collected samples from hundreds of trees in
Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...
and compared their genetic profiles to samples from Hawaiian orchards. They determined that essentially all the Hawaiian trees must have descended from a small population of Australian trees from
Gympie Gympie ( ) is a city and a Suburbs and localities (Australia), locality in the Gympie Region, Queensland, Australia. In the Wide Bay-Burnett District, Gympie is about north of the state capital, Brisbane. The city lies on the Mary River (Queen ...
, possibly just a single tree. This lack of genetic diversity in the commercial crop puts it at risk of succumbing to pathogens (as has happened in the past to
banana A banana is an elongated, edible fruit – botanically a berry – produced by several kinds of large herbaceous flowering plants in the genus ''Musa''. In some countries, bananas used for cooking may be called "plantains", distinguis ...
cultivars). Growers may seek to diversify the cultivated population by hybridizing with wild specimens.


Nutrition

Raw macadamia nuts are 1% water, 14%
carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...
s, 76%
fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers spec ...
, and 8%
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
(table). A 100-gram reference amount of macadamia nuts provides 740
kilocalories The calorie is a unit of energy. For historical reasons, two main definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the amount of heat needed to raise the temperature of on ...
and are a rich source (20% or more of the
Daily Value The Reference Daily Intake (RDI) used in nutrition labeling on food and dietary supplement products in the U.S. and Canada is the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97–98% of health ...
(DV)) of numerous
essential nutrients A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excre ...
, including
thiamine Thiamine, also known as thiamin and vitamin B1, is a vitamin, an essential micronutrient, that cannot be made in the body. It is found in food and commercially synthesized to be a dietary supplement or medication. Phosphorylated forms of thi ...
(104% DV), vitamin B6 (21% DV), other
B vitamins B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism and synthesis of red blood cells. Though these vitamins share similar names (B1, B2, B3, etc.), they are chemically distinct compounds that often coexist ...
,
manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
(195% DV),
iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
(28% DV),
magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
(37% DV) and
phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
(27% DV) (table). Compared with other common edible nuts, such as
almond The almond (''Prunus amygdalus'', syn. ''Prunus dulcis'') is a species of tree native to Iran and surrounding countries, including the Levant. The almond is also the name of the edible and widely cultivated seed of this tree. Within the genus ...
s and
cashew The cashew tree (''Anacardium occidentale'') is a tropical evergreen tree native to South America in the genus ''Anacardium'' that produces the cashew seed and the cashew apple accessory fruit. The tree can grow as tall as , but the dwarf cult ...
s, macadamias are high in total fat and relatively low in protein. They have a high amount of
monounsaturated fat Monounsaturated fats are fatty acids that have one double bond in the fatty acid chain with all of the remainder carbon atoms being single-bonded. By contrast, polyunsaturated fats have more than one double bond. Molecular description Fatty aci ...
s (59% of total content) and contain, as 17% of total fat, the
monounsaturated fat Monounsaturated fats are fatty acids that have one double bond in the fatty acid chain with all of the remainder carbon atoms being single-bonded. By contrast, polyunsaturated fats have more than one double bond. Molecular description Fatty aci ...
, omega-7
palmitoleic acid Palmitoleic acid, or (9''Z'')-hexadec-9-enoic acid, is an omega-7 monounsaturated fatty acid (16:1n-7) with the formula CH3(CH2)5CH=CH(CH2)7COOH that is a common constituent of the glycerides of human adipose tissue. It is present in all tissues ...
.


Toxicity in dogs

Macadamias are
toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...
to dogs.
Ingestion Ingestion is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in a substance through the mouth into the gastrointestinal tract, such as through eating or drinking. In single-celled organisms ingest ...
may result in macadamia toxicity marked by
weakness Weakness is a symptom of a number of different conditions. The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, i ...
and hind limb paralysis with the inability to stand, occurring within 12 hours of ingestion. It is not known what makes macadamia nuts toxic, but its effects have only been reported in dogs. Depending on the quantity ingested and the size of the dog, symptoms may also include muscle tremors, joint pain, and severe abdominal pain. In high doses of toxin, opiate medication may be required for symptom relief until the toxic effects diminish, with full recovery usually within 24 to 48 hours.


Other uses

The trees are also grown as
ornamental plant Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that i ...
s in subtropical regions for their glossy foliage and attractive flowers. The flowers produce a well-regarded honey. The wood is used decoratively for small items. ''Macadamia'' species are used as food plants 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 ...
e of some
Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...
species, including ''
Batrachedra arenosella ''Batrachedra arenosella'', the armoured scale eating caterpillar or the coconut moth, is a species of moth of the family Batrachedridae. It was first described by Francis Walker using specimens collected in Auckland, New Zealand. It has been hypo ...
''. Macadamia seeds are often fed to
hyacinth macaw The hyacinth macaw (''Anodorhynchus hyacinthinus''), or hyacinthine macaw, is a parrot native to central and eastern South America. With a length (from the top of its head to the tip of its long pointed tail) of about one meter it is longer tha ...
s in captivity. These large
parrot Parrots, also known as psittacines (), are birds of the roughly 398 species in 92 genera comprising the order Psittaciformes (), found mostly in tropical and subtropical regions. The order is subdivided into three superfamilies: the Psittacoid ...
s are one of the few animals, aside from humans, capable of cracking the shell and removing the seed.


See also

*
Macadamia oil Macadamia oil (or macadamia nut oil) is the non-volatile oil collected from the nuts of the macadamia (''Macadamia integrifolia''), a native Australian plant. It is used in food as a frying or salad oil, and in cosmetic formulations as an emollien ...


References


External links

* {{Taxonbar, from=Q310041 Australian cuisine Cuisine of Brisbane Edible nuts and seeds Fruit trees Proteaceae genera Hawaiian cuisine Proteales of Australia Endemic flora of Australia