Editing Macadamia

{{Short description|Genus of plants indigenous to Australia}}
{{Use Australian English|date=April 2014}}
{{Use dmy dates|date=October 2021}}
{{Automatic taxobox
| image             = Macadamia nuts on tree.JPG
| image_caption     = Macadamia nuts
| display_parents   = 3
| taxon             = Macadamia
| authority         = [[Ferdinand von Mueller|F.Muell.]]
| type_species      = ''[[Macadamia integrifolia]]''
| type_species_authority = [[Joseph Maiden|Maiden]] & [[Ernst Betche|Betche]]
| subdivision_ranks = Species
| subdivision       = 
* ''[[Macadamia integrifolia]]'' {{Au|[[Joseph Maiden|Maiden]] & [[Ernst Betche|Betche]]}}
* ''[[Macadamia jansenii]]'' {{Au|C.L.Gross & P.H.Weston}}
* ''[[Macadamia ternifolia]]'' {{Au|[[Ferdinand von Mueller|F.Muell.]]}}
* ''[[Macadamia tetraphylla]]'' {{Au|[[Lawrence Alexander Sidney Johnson|L.A.S.Johnson]]}}
}}

'''''Macadamia''''' is a [[genus]] of four [[species]] of trees in the [[flowering plant]] family [[Proteaceae]].<ref name="APNI">{{cite web |url=https://id.biodiversity.org.au/name/apni/99964 |title=''Macadamia'' |website=[[Australian Plant Name Index]] (APNI) |publisher=Centre for Plant Biodiversity Research, [[Australian Government]] |access-date=15 March 2023}}</ref><ref name=Mastetal2008>{{Cite journal | last1 = Mast | first1 = Austin R. | last2 = Willis | first2 = Crystal L. | last3 = Jones | first3 = Eric H. | last4 = Downs | first4 = Katherine M. | last5 = Weston | first5 = Peter H. | date = July 2008 | title = A smaller ''Macadamia'' from a more vagile tribe: inference of phylogenetic relationships, divergence times, and diaspore evolution in ''Macadamia'' and relatives (tribe Macadamieae; Proteaceae) | journal = American Journal of Botany | volume = 95 | issue = #7 | pages = 843–870 | issn = 1537-2197 | doi = 10.3732/ajb.0700006 | pmid = 21632410 | bibcode = 2008AmJB...95..843M }}</ref> They are indigenous to Australia - specifically, northeastern [[New South Wales]] and central and southeastern [[Queensland]]. Two species of the [[genus]] are commercially important for their fruit, the '''macadamia nut''' {{IPAc-en|ˌ|m|æ|k|ə|ˈ|d|eɪ|m|i|ə}} (or simply '''macadamia'''). Global production in 2015 was {{convert|160000|t|ST}}.<ref name="fp">{{cite web | url=http://www.freshplaza.com/article/137977/South-Africa-becomes-king-of-macadamia-nuts-again | title=South Africa becomes king of macadamia nuts again | publisher=FreshPlaza | date=14 April 2015 | access-date=9 October 2016 | archive-url=https://web.archive.org/web/20161010043705/http://www.freshplaza.com/article/137977/South-Africa-becomes-king-of-macadamia-nuts-again | archive-date=10 October 2016 | url-status=dead }}</ref> Other names include '''Queensland nut''', '''bush nut''', '''maroochi nut''' or '''bauple nut'''.<ref name="bopplenut">{{Cite web|title=The Bopple Nut|url=http://www.bauplemuseum.com/bopple%20nut%20pub.pdf|url-status=dead|archive-url=https://web.archive.org/web/20140811101924/http://bauplemuseum.com/bopple%20nut%20pub.pdf|archive-date=11 August 2014|access-date=19 June 2014|website=Bauple Museum}}</ref> It was an important source of [[Bush tucker|bushfood]] for the [[Aboriginal Australians|Aboriginal peoples]].

[[File:Bolivia Macadamia (4370865469).jpg|thumb|Fresh macadamia nut with husk or [[pericarp]] cut in half]]
[[File:Starr-081111-0455-Macadamia integrifolia-different stages-Makawao-Maui (24299912723).jpg|thumb|Stages of a ''Macadamia integrifolia'' nut: unripe, ripe, husk peeled, deshelled]]
[[File:Macadamia_nuts,_with_one_cracked_and_exposing_the_nut.jpg|thumb|Roasted macadamia nuts with sawn nutshell, one cracked open]]

The nut was first commercially produced on a wide scale in [[Hawaii]], where Australian seeds were introduced in the 1880s, and for more than a century they were the world's largest producer.<ref name="TG-20201212">{{cite news |last1=Kean |first1=Zoe |title=In a nutshell: how the macadamia became a 'vulnerable' species |url=https://www.theguardian.com/environment/2020/dec/12/in-a-nutshell-how-the-macadamia-became-a-vulnerable-species-aoe |access-date=14 December 2020 |work=The Guardian |date=12 December 2020}}</ref><ref>{{cite book|url=https://www.ctahr.hawaii.edu/oc/freepubs/pdf/RES-039.pdf|series=Research extension series|issn=0271-9916|title=Macadamia nuts in Hawaii: History and production|last1=Shigeura|first1=Gordon T.|first2=Hiroshi|last2=Ooka|date=April 1984|publisher=University of Hawaii. College of Tropical Agriculture and Human Resources|access-date=1 June 2020|archive-date=22 September 2019|archive-url=https://web.archive.org/web/20190922090216/https://www.ctahr.hawaii.edu/oc/freepubs/pdf/RES-039.pdf|url-status=dead}}</ref> South Africa has been the world's largest producer of the macadamia since the 2010s. 

The macadamia is the only widely grown food plant that is native to Australia.<ref>{{Cite web|url=https://www.cambridge.org/core/blog/2024/02/08/australian-plants-can-be-new-food-crops-for-sustainable-agricultural-systems/|title=Australian plants can be new food crops for sustainable agricultural systems|date=8 February 2024}}</ref>

==Description==
''Macadamia'' is a genus of [[evergreen]] trees that grows {{Convert|2|–|12|m|ft|abbr=on|sigfig=1}} tall.

The leaves are arranged in [[Whorl (botany)|whorl]]s of three to six, [[lanceolate]] to [[obovate]] or [[elliptic]] in [[Leaf shape|shape]], {{convert|60|–|300|mm|in|frac=2|abbr=on|sigfig=1}} long and {{convert|30|–|130|mm|in|frac=8|abbr=on|sigfig=1}} broad, with an entire or spiny-serrated margin. The flowers are produced in a long, slender, and simple [[raceme]] {{convert|50|–|300|mm|in|frac=2|abbr=on|sigfig=1}} long, the individual flowers {{convert|10|–|15|mm|in|frac=16|abbr=on|sigfig=1}} long, white to pink or purple, with four [[tepal]]s. The fruit is a hard, woody, globose [[Follicle (fruit)|follicle]] with a pointed apex containing one or two [[seed]]s. The nutshell ("coat") is particularly tough and requires around 2000 [[Newton (unit)|N]] to crack. The shell material is five times harder than [[hazelnut]] shells<!--by density--> and has mechanical properties similar to [[Aluminium|aluminum]]. It has a [[Vickers hardness test|Vickers hardness]] of 35.<ref>{{cite journal |last1=Schüler |first1=Paul |last2=Speck |first2=Thomas |last3=Bührig-Polaczek |first3=Andreas |last4=Fleck |first4=Claudia |last5=Buehler |first5=Markus J. |title=Structure-Function Relationships in Macadamia integrifolia Seed Coats – Fundamentals of the Hierarchical Microstructure |journal=PLOS ONE|date=7 August 2014 |volume=9 |issue=#8 |pages=e102913 |doi=10.1371/journal.pone.0102913|pmid=25102155 |pmc=4125148 |bibcode=2014PLoSO...9j2913S |doi-access=free }}</ref><ref>{{cite journal |last1=Jennings |first1=J. S. |last2=Macmillan |first2=N. H. |title=A tough nut to crack |journal=Journal of Materials Science |date=May 1986 |volume=21 |issue=#5 |pages=1517–1524 |doi=10.1007/BF01114704|bibcode=1986JMatS..21.1517J |s2cid=136850984 }}</ref>

==Taxonomy==

=== Species ===
{| class="wikitable"
|-
! Image !! Scientific Name  !! Distribution
|-
|[[File:Starr 080715-9228 Macadamia integrifolia.jpg|120px]] ||''[[Macadamia integrifolia]]'' {{au|[[Joseph Maiden|Maiden]] & [[Ernst Betche|Betche]]}}||south east Queensland and extreme adjacent northern New South Wales
|-
|[[File:Macadamia jansenii juvenile.jpg|120px]] || ''[[Macadamia jansenii]]'' {{au|C.L.Gross & P.H.Weston}} || Queensland
|-
|[[File:Macadamia ternifolia kz2.jpg|120px]] || ''[[Macadamia ternifolia]]'' {{au|[[Ferdinand von Mueller|F.Muell.]]}}||Queensland
|-
|[[File:Macadamia tetraphylla in Hackfalls Arboretum (6).jpg|120px]] || ''[[Macadamia tetraphylla]]'' {{au|[[Lawrence Alexander Sidney Johnson|L.A.S.Johnson]]}}|| extreme south east Queensland and northern New South Wales
|-
|}

Nuts from ''M. jansenii'' and ''M. ternifolia'' contain [[Glycoside#Cyanogenic glycosides|cyanogenic glycosides]].<ref name="Sharma">{{cite journal | last1=Sharma | first1=Priyanka | last2=Murigneux | first2=Valentine | last3=Haimovitz | first3=Jasmine | last4=Nock | first4=Catherine J. | last5=Tian | first5=Wei | last6=Kharabian Masouleh | first6=Ardashir | last7=Topp | first7=Bruce | last8=Alam | first8=Mobashwer | last9=Furtado | first9=Agnelo | last10=Henry | first10=Robert J. | title=The genome of the endangered ''Macadamia jansenii'' displays little diversity but represents an important genetic resource for plant breeding | journal=Plant Direct | volume=5 | issue=12 | year=2021 | pages=e364 | issn=2475-4455 | doi=10.1002/pld3.364| pmid=34938939| pmc=8671617 | bibcode=2021PlanD...5E.364S }}</ref><ref name="Dahler">{{cite journal | last1=Dahler | first1=JM | last2=Mcconchie | first2=C | last3=Turnbull | first3=CGN | title=Quantification of Cyanogenic Glycosides in Seedlings of Three Macadamia (Proteaceae) Species | journal=Australian Journal of Botany | year=1995 | volume=43 | issue=6 | issn=1444-9862 | doi=10.1071/bt9950619 | pages=619–628 | bibcode=1995AuJB...43..619D | url=https://www.publish.csiro.au/bt/bt9950619 | access-date=2022-02-16| url-access=subscription }}</ref> The other two species are cultivated for the commercial production of macadamia nuts for human consumption.

Previously, more species with [[disjunct distribution]]s were named as members of this genus ''Macadamia''.<ref name=Mastetal2008/> Genetics and [[Morphology (biology)|morphological]] studies published in 2008 show they have separated from the genus ''Macadamia'', correlating less closely than thought from earlier morphological studies.<ref name=Mastetal2008/> 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]]'' {{au|P.H.Weston & [[Austin Mast|A.R.Mast]]}}, formerly ''Macadamia'' until 2008
* ''[[Lasjia claudiensis]]'' {{au|(C.L.Gross & [[Bernard Hyland|B.Hyland]]) {{interlanguage link|Peter H. Weston|az|Piter Henri Ueston|es|Peter Henry Weston|it|Peter Henry Weston|ru|Уэстон, Питер Хенри}} & A.R.Mast}}; synonym, [[basionym|base name]]: ''Macadamia claudiensis'' {{au|C.L.Gross & B.Hyland}}
* ''[[Lasjia erecta]]'' {{au|(J.A.McDonald & R.Ismail) P.H.Weston & A.R.Mast}}; synonym, base name: ''Macadamia erecta'' {{au|J.A.McDonald & R.Ismail}}<br />A tree [[endemic]] to the island of [[Sulawesi]], Indonesia. First described by science in 1995.<ref>{{cite journal|url=https://www.jstor.org/stable/41761991|title=Macadamia erecta (Proteaceae), a New Species from Sulawesi |publisher=Harvard University Herbaria|journal=Harvard Papers in Botany|author=J. Andrew McDonald and Ismail, R.|date=September 1995|volume=1 |issue=#7 |pages=7–10 |jstor=41761991 |access-date=18 February 2021}}</ref>
* ''[[Lasjia grandis]]'' {{au|(C.L.Gross & B.Hyland) P.H.Weston & A.R.Mast}}; synonym, base name: ''Macadamia grandis'' {{au|C.L.Gross & B.Hyland}}
* ''[[Lasjia hildebrandii]]'' {{au|([[Cornelis Gijsbert Gerrit Jan van Steenis|Steenis]]) P.H.Weston & A.R.Mast}}; synonym, base name: ''Macadamia hildebrandii'' {{au|Steenis}}<!--, Reinwardtia i: 475. 1952. --><br />Another species endemic to Sulawesi.<ref>{{cite web|url=https://pfaf.org/user/Plant.aspx?LatinName=Macadamia+hildebrandii|title=Macadamia hildebrandii - Steenis|publisher=Plants for a Future|access-date=18 February 2021}}</ref><ref>{{cite journal |url=https://smujo.id/biodiv/article/view/4814 |title=Spatial distribution and habitat characteristics of Macadamia hildebrandii in the Sintuwu Maroso Protection Forest, Central Sulawesi, Indonesia |author1=Akhbar |author2=Nuryanti S.  |author3=Naharuddin |journal=Biodiversitas Journal of Biological Diversity |volume=20 |issue=#2 |year=2020 |doi=10.13057/biodiv/d210245 |access-date=18 February 2021 |doi-access=free}}</ref>
* ''[[Lasjia whelanii]]'' {{au|([[Frederick Manson Bailey|F.M.Bailey]]) P.H.Weston & A.R.Mast}}; synonyms: base name: ''Helicia whelanii'' {{au|F.M.Bailey}}<!--, Report on New Plants, Preliminary to General Report on Botanical Results on Mestons Expedition to the Bellenden-Ker Range. p. 2. 1889. -->, ''Macadamia whelanii'' {{au|(F.M.Bailey) F.M.Bailey}}

;''[[Catalepidia]]'' {{interlanguage link|Peter H. Weston|az|Piter Henri Ueston|es|Peter Henry Weston|it|Peter Henry Weston|ru|Уэстон, Питер Хенри}}, formerly ''Macadamia'' until 1995
* ''[[Catalepidia heyana]]'' {{au|(F.M.Bailey) P.H.Weston}}; synonyms: base name: ''Helicia heyana'' {{au|F.M.Bailey}} <!--Queensland Fl. 4: 1329 (1901) -->, ''Macadamia heyana'' {{au|(F.M.Bailey) [[Hermann Otto Sleumer|Sleumer]]}}

;''[[Virotia]]'' {{au|[[Lawrence Alexander Sidney Johnson|L.A.S.Johnson]] & [[Barbara G. Briggs|B.G.Briggs]]}}, formerly ''Macadamia'' until the first species renaming began in 1975 and comprehensive in 2008
* ''[[Virotia angustifolia]]'' {{au|([[Robert Virot|Virot]]) P.H.Weston & A.R.Mast}}; synonym, base name: ''Macadamia angustifolia'' {{au|Virot}}
* ''[[Virotia francii]]'' {{au|([[André Guillaumin|Guillaumin]]) P.H.Weston & A.R.Mast}}; synonym, base name: ''[[Roupala]] francii'' {{au|Guillaumin}}
* ''[[Virotia leptophylla]]'' {{au|(Guillaumin) L.A.S.Johnson & B.G.Briggs}} (1975 type species); synonym, base name: ''[[Kermadecia]] leptophylla'' {{au|Guillaumin}} 
* ''[[Virotia neurophylla]]'' {{au|(Guillaumin) P.H.Weston & A.R.Mast}}; synonyms: base name: ''[[Kermadecia]] neurophylla'' {{au|Guillaumin}}, ''Macadamia neurophylla'' {{au|(Guillaumin) Virot}}
* ''[[Virotia rousselii]]'' {{au|([[Vieill.]]) P.H.Weston & A.R.Mast}}; synonym, base name: ''Roupala rousselii'' {{au|Vieill}}
* ''[[Virotia vieillardi]]'' {{au|([[Adolphe-Théodore Brongniart|Brongn.]] & [[Jean Antoine Arthur Gris|Gris]]) P.H.Weston & A.R.Mast}}; synonym, base name: ''Roupala vieillardii'' {{au|Brongn. & Gris}}

=== Etymology ===
The German-Australian [[botany|botanist]] [[Ferdinand von Mueller]] gave the genus the name ''Macadamia'' in 1857 in honour of the Scottish-Australian [[chemist]], medical teacher, and [[politician]] [[John Macadam]], who was the honorary Secretary of the [[Philosophical Institute of Victoria]] beginning in 1857.<ref>The proceedings of Philosophical Institute of Victoria, now the [[Royal Society of Victoria]] Rev: Mueller F (1857) Account of some new Australian plants. ''Transactions of the Philosophical Institute of Victoria'' 2: 62–77; Burke & Wills: The Scientific Legacy of the Victorian Exploring Expedition by E B Joyce & D A McCann, ''Royal Society of Victoria'' 2011</ref>

== Cultivation ==
[[Image:Macadamia integrifolia, buds.jpg|thumb|''Macadamia integrifolia'' flowers]]

The macadamia tree is usually propagated by [[grafting]]. It 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 {{convert|1000|-|2000|mm|abbr=on|sigfig=1}}, and temperatures not falling below {{convert|10|C|F|sigfig=1}} (although once established, they can withstand light frosts), with an optimum temperature of {{convert|25|C|F|sigfig=1}}. The roots are shallow, and trees can be blown down in storms; like most [[Proteaceae]], they are also susceptible to ''[[Phytophthora]]'' root disease. As of 2019, the macadamia nut is the most expensive nut in the world, which is attributed to the slow harvesting process.<ref>{{cite web |url=https://www.businessinsider.com/macadamia-nuts-most-expensive-world-australia-hawaii-2019-3 |title=What makes macadamia nuts the most expensive nuts in the world, at $25 per pound |last=Kim |first=Irene Anna |date=6 March 2019 |website=Business Insider |access-date=8 July 2020 |archive-date=26 August 2019 |archive-url=https://web.archive.org/web/20190826071135/https://www.businessinsider.com/macadamia-nuts-most-expensive-world-australia-hawaii-2019-3 |url-status=live }}</ref>

[[Image:Macadamia Beaumont.JPG|right|thumb|Macadamia 'Beaumont' in new growth]]

=== Cultivars ===

==== Beaumont ====
A ''[[Macadamia integrifolia]]'' / ''[[Macadamia tetraphylla|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 {{convert|18|kg|abbr=on}} 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.
[[Image:Macadamia Maroochy.JPG|right|thumb|Macadamia 'Maroochy' new growth]]

==== Maroochy ====
A pure ''[[Macadamia tetraphylla|M. tetraphylla]]'' variety from Australia, this strain is cultivated for its productive crop yield, flavour, and suitability for pollinating 'Beaumont.'

==== Nelmac II ====
A South African ''M. integrifolia'' / ''M. tetraphylla'' hybrid cultivar, it has a sweet seed, which means it must 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  {{convert|22|kg|abbr=on|sigfig=1}} 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; {{convert|17|kg|abbr=on}} from a 9-year-old tree has been recorded, and the nuts drop to the ground. However, they are thick-shelled, with not much flavour.

==Production==
In 2024, [[South Africa]] was the leading producer of macadamia nuts, with 77,000 tonnes,<ref>{{Cite web |last=Brederode |first=William |title=SA is world's biggest macadamia producer - why it now has to start cracking nuts to survive |url=https://www.news24.com/fin24/economy/sa-is-worlds-biggest-macadamia-producer-why-it-now-has-to-start-cracking-nuts-to-survive-20240303 |access-date=2024-12-25 |website=Business |language=en-US}}</ref> up from 54,000 tonnes out of global production of 211,000 tonnes in 2018.<ref name="agrio">{{Cite web|url=https://www.agriorbit.com/more-and-more-macadamia-produced-globally-world-nut-conference/|title=More and more macadamia produced globally|last=Motaung|first=Ntswaki|date=2018-05-30|website=Agriorbit|language=en-US|access-date=2019-01-15|archive-date=15 January 2019|archive-url=https://web.archive.org/web/20190115235620/https://www.agriorbit.com/more-and-more-macadamia-produced-globally-world-nut-conference/|url-status=dead}}</ref> Macadamia is commercially produced in many countries of Southeast Asia, South America, Australia, and North America having [[Mediterranean climate|Mediterranean]], [[temperate climate|temperate]] or [[tropical climate]]s.<ref name="agrio" />

===History===
The first commercial orchard of macadamia trees was planted in the early 1880s by Rous Mill, {{convert|12|km|abbr=on}} southeast of [[Lismore, New South Wales]], consisting of ''[[Macadamia tetraphylla|M. tetraphylla]]''.<ref>{{Cite book | author=Macadamia Power Pty | year=1982 | title=Macadamia Power in a Nutshell | publisher=Macadamia Power Pty Limited | page=13 |isbn=978-0-9592892-0-6}}</ref> 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]] from the 1920s onward. Macadamia seeds were first imported into Hawaii in 1882 by [[William H. Purvis]], who planted seeds that year at [[Kapulena]].<ref>{{Cite web | last=Schmitt | first=Robert | url=http://www.hawaiianhistory.org/moments/macadami.html | title=Macadamia Nuts | publisher=Hawaiian Historical Society | access-date=7 April 2012 | url-status=dead | archive-url=https://web.archive.org/web/20120216230519/http://www.hawaiianhistory.org/moments/macadami.html | archive-date=16 February 2012 }}</ref> The Hawaiian-produced macadamia established the well-known seed internationally, and in 2017, Hawaii produced over 22,000 tonnes.<ref>{{Cite web|url=https://quickstats.nass.usda.gov/results/CEB3B9C1-2EDD-36CB-AF22-702C81A481C0|title=USDA/NASS QuickStats Ad-hoc Query Tool|website=quickstats.nass.usda.gov|access-date=2019-01-15|archive-date=16 January 2019|archive-url=https://web.archive.org/web/20190116045804/https://quickstats.nass.usda.gov/results/CEB3B9C1-2EDD-36CB-AF22-702C81A481C0|url-status=dead}}</ref>

In 2019, researchers collected samples from hundreds of trees in [[Queensland]] 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]], possibly just a single tree.<ref>{{Cite web | last=Imbler | first=Sabrina | url=https://www.atlasobscura.com/articles/macadamias-came-from-one-tree | title=70 Percent of the World's Macadamia Nuts Came From One Tree in Australia | date=3 June 2019 | publisher=Atlas Obscura | access-date=2019-06-05 | archive-date=7 June 2019 | archive-url=https://web.archive.org/web/20190607085126/https://www.atlasobscura.com/articles/macadamias-came-from-one-tree | url-status=live }}</ref> 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]] cultivars). Growers may seek to diversify the cultivated population by hybridizing with wild specimens.

===Shelling===
[[File:Macadamia cracking tool.jpg|thumb|Screw-type macadamia nut cracker on a plate of unshelled macadamias]]

Macadamias are the world's hardest edible nut to crack.<ref name="am">{{cite web | url=https://www.australian-macadamias.org/grow/how-to-crack-a-macadamia-nut/ | title=How to crack a macadamia nut }}</ref> Since ordinary [[nutcracker]]s apply insufficient force,<ref name="shellingmachine">{{cite web | url=https://www.shellingmachine.com/application/south-africa-macadamia-nuts-processing-industry.html | title=Macadamia Nuts Processing Industry in South Africa | date=25 June 2019 }}</ref> various types of specialist macadamia nut crackers are available, many of which apply force to the [[Micropyle (botany)|micropyle]], visible as a white dot, to fracture the shell.<ref name="am"/>

For commercial scale deshelling, rotating steel rollers are used.<ref name="shellingmachine"/> In South Africa, the average crack-out rate, meaning the ratio of usable nut to discarded shell, is 27.6% nut to 72.4% waste.<ref name="shellingmachine"/>

== Toxicity ==
Nuts from ''M. jansenii'' and ''M. ternifolia'' contain cyanogenic glycosides.<ref name="Sharma" /><ref name="Dahler" /> 

===Allergen===
Macadamia allergy is a type of [[food allergy]] to macadamia nuts which is relatively rare, affecting less than 5% of people with [[tree nut allergy]] in the United States.<ref name="Cox">{{cite journal |last1=Cox |first1=A.L. |last2=Eigenmann |first2=P.A. |last3=Sicherer |first3=S.H. |date=2021 |title=Clinical Relevance of Cross-Reactivity in Food Allergy |url=https://www.jaci-inpractice.org/article/S2213-2198(20)31008-4/fulltext |journal=The Journal of Allergy and Clinical Immunology: In Practice |volume=9 |issue=1 |pages=82–99 |doi=10.1016/j.jaip.2020.09.030 |pmid=33429724 |s2cid=231587027 |access-date=6 May 2023|url-access=subscription }}</ref> Macadamia allergy can cause mild to severe allergic reactions, such as [[oral allergy syndrome]], [[urticaria]], [[angioedema]], vomiting, abdominal pain, [[asthma]], and [[anaphylaxis]].<ref name="Yoshida">{{cite journal |last1=Yoshida |first1=K |last2=Shirane |first2=S |last3=Kinoshita |first3=K |date=2021 |title=Macadamia nut allergy in children: Clinical features and cross-reactivity with walnut and hazelnut. |url=https://onlinelibrary.wiley.com/doi/10.1111/pai.13469 |journal=Pediatric Allergy and Immunology |volume=32 |issue=5 |pages=111–1114 |doi=10.1111/pai.13469 |pmid=33559377 |s2cid=231863665 |access-date=6 May 2023|url-access=subscription }}</ref> Macadamia allergy can also cross-react with other tree nuts or foods that have similar allergenic proteins, such as [[coconut]], [[walnut]], [[hazelnut]], and [[cashew]].<ref name="f345">{{cite web |title=f345 Macadamia nut |url=https://www.thermofisher.com/diagnostic-education/hcp/gb/en/resource-center/allergen-encyclopedia/whole-allergens.html?key=f345 |access-date=6 May 2023 |website=Allergy & Autoimmune Disease}}</ref> The diagnosis and management of macadamia allergy involves avoiding macadamia nuts and their derivatives, reading food labels carefully, carrying an [[epinephrine auto-injector]] in case of severe reactions, and consulting a doctor for further testing and advice.

===Toxicity in dogs and cats===
Macadamias are [[toxic]] to dogs. [[Ingestion]] may result in macadamia toxicity marked by [[weakness]] and hind limb paralysis with the inability to stand, occurring within 12 hours of ingestion.<ref name="ca">{{cite journal |author=Christine Allen |date=October 2001 |title=Treacherous Treats – Macadamia Nuts |url=http://aspcapro.org/sites/pro/files/zj-vettech_1001_0.pdf |url-status=dead |journal=Veterinary Technician |archive-url=https://web.archive.org/web/20140116100009/http://aspcapro.org/sites/pro/files/zj-vettech_1001_0.pdf |archive-date=16 January 2014 |access-date=15 January 2014}}</ref> It is not known what makes macadamia nuts toxic in dogs.<ref>{{cite web |title=Macadamia Nut Toxicity |url=https://www.thesprucepets.com/macadamia-nuts-and-dogs-dont-mix-3385507 |access-date=30 March 2021 |website=The Spruce Pets}}</ref> 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.<ref name="ca" />

Macadamias are also toxic to cats, causing tremors, paralysis, joint stiffness, and high fever.<ref>David Brunner, Sam Stall: ''Die Katze.'' Sanssouci, München/Wien 2005, {{ISBN|3-7254-1357-6}}, S.&nbsp;181.</ref>

{{nutritionalvalue
| name=Macadamia nuts, raw
| kJ=3080
| water=1.4 g
| fat=75.8 g
| satfat=12 g
| monofat=59 g
| polyfat=1.5 g
| protein=7.9 g
| carbs=13.8 g
| fiber=8.6 g
| sugars=4.57 g
| iron_mg=3.69
| calcium_mg=85
| magnesium_mg=130
| phosphorus_mg=188
| potassium_mg=368
| manganese_mg=4.1
| zinc_mg=1.30
| vitC_mg=1.2
| vitE_mg=0.54
| thiamin_mg=1.195
| riboflavin_mg=0.162
| niacin_mg=2.473
| pantothenic_mg=0.76
| vitB6_mg=0.275
| folate_ug=11
| note=[https://fdc.nal.usda.gov/fdc-app.html#/food-details/170178/nutrients Link to USDA Database entry]
}}

== Uses ==

=== Nutrition ===
Raw macadamia nuts are 1% water, 14% [[carbohydrate]]s, 76% [[fat]], and 8% [[protein (nutrient)|protein]]. A 100-gram reference amount of macadamia nuts provides 740 [[kilocalories]] and are a rich source (20% or more of the [[Daily Value]] (DV)) of numerous [[essential nutrients]], including [[thiamine]] (104% DV), [[vitamin B6|vitamin B<sub>6</sub>]] (21% DV), other [[B vitamins]], [[manganese]] (195% DV), [[iron]] (28% DV), [[magnesium]] (37% DV) and [[phosphorus]] (27% DV).

Compared with other common edible nuts, such as [[almond]]s and [[cashew]]s, macadamias are high in total fat and relatively low in protein. They have a high amount of [[monounsaturated fat]]s (59% of total content) and contain, as 17% of total fat, the [[monounsaturated fat]], [[omega-7 fatty acid|omega-7]] [[palmitoleic acid]].<ref>{{cite web|url=http://nutritiondata.self.com/facts/nut-and-seed-products/3123/2|title=Macadamia nuts, raw, per 100 g| publisher=Conde Nast for the USDA National Nutrient Database, release SR 21|date=2014|access-date=14 January 2016|archive-date=14 January 2016|archive-url=https://web.archive.org/web/20160114223010/http://nutritiondata.self.com/facts/nut-and-seed-products/3123/2|url-status=dead}}</ref>

=== Other uses ===
The trees are also grown as [[ornamental plant]]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.<ref>{{cite web |title=Macadamia Nut {{!}} The Wood Database – Lumber Identification (Hardwood) |url=https://www.wood-database.com/macadamia-nut/ |access-date=19 August 2019 |archive-date=14 May 2019 |archive-url=https://web.archive.org/web/20190514124439/https://www.wood-database.com/macadamia-nut/ |url-status=live }}</ref> ''Macadamia'' species are used as food plants by the [[larva]]e of some [[Lepidoptera]] species, including ''[[Batrachedra|Batrachedra arenosella]]''.{{citation needed|date=May 2023}}

Macadamia seeds are often fed to [[hyacinth macaw]]s in captivity. These large [[parrot]]s are among the few animals, other than humans, capable of cracking the shell and removing the seed.<ref>{{cite journal | author=Kashmir Csaky | date=November 2001 | url=http://www.bluemacaws.org/avi18.htm | title=The Hyacinth Macaw | journal=Parrots Magazine | access-date=6 December 2010 | archive-date=12 June 2007 | archive-url=https://web.archive.org/web/20070612040410/http://www.bluemacaws.org/avi18.htm | url-status=dead }}</ref>

== Modern history ==
;1828
:[[Allan Cunningham (botanist)|Allan Cunningham]] was the first European to encounter the macadamia plant in Australia.<ref>{{cite news |last1=Wilson |first1=Bee |date=5 October 2010 |title=The Kitchen Thinker: Macadamias |url=https://www.telegraph.co.uk/foodanddrink/8028252/The-Kitchen-Thinker-Macadamias.html |url-status=live |archive-url=https://web.archive.org/web/20190217030221/https://www.telegraph.co.uk/foodanddrink/8028252/The-Kitchen-Thinker-Macadamias.html |archive-date=17 February 2019 |access-date=11 July 2017 |agency=The Telegraph}}</ref>
;1857–1858
:German-Australian botanist [[Ferdinand von Mueller]] 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.<ref>{{Cite book |last1=Shigeura |first1=Gordon T. |url=https://www.ctahr.hawaii.edu/oc/freepubs/pdf/RES-039.pdf |title=Macadamia nuts in Hawaii: history and production |last2=Ooka |first2=Hiroshi |publisher=University of Hawaii |year=1984 |location=Honolulu, HI |pages=8 |access-date=10 July 2017 |archive-url=https://web.archive.org/web/20161224160755/http://www.ctahr.hawaii.edu/oc/freepubs/pdf/RES-039.pdf |archive-date=24 December 2016 |url-status=dead}}</ref>
;1858
:'Bauple nuts' were discovered in [[Bauple, Queensland]]; they are now known as macadamia nuts.
:[[Walter Hill (garden curator)|Walter Hill]], superintendent of the [[City Botanic Gardens|Brisbane Botanic Gardens]] (Australia), observed a boy eating the kernel without ill effect, becoming the first nonindigenous person recorded to eat macadamia nuts.<ref>{{Cite book |last=McKinnon |first=Ross |url=http://adb.anu.edu.au/biography/hill-walter-12981 |title=Australian Dictionary of Biography |publisher=National Centre of Biography, Australian National University |location=Canberra |chapter=Hill, Walter (1819–1904) |access-date=12 February 2018 |archive-url=https://web.archive.org/web/20180213022455/http://adb.anu.edu.au/biography/hill-walter-12981 |archive-date=13 February 2018 |url-status=dead}}</ref>
;1860s
:King Jacky, an 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.<ref>{{Cite journal |last1=McConachie |first1=Ian |year=1980 |title=The Macadamia Story |url=http://www.australian-macadamias.org/download.php?file=macstory.pdf |url-status=live |journal=California Macadamia Society Yearbook |volume=26 |pages=41–47 |archive-url=https://web.archive.org/web/20140111081436/http://www.australian-macadamias.org/download.php?file=macstory.pdf |archive-date=11 January 2014 |access-date=11 January 2014}}</ref>
;1866
: [[Thomas Petrie|Tom Petrie]] planted macadamias at Yebri Creek (near Petrie) from nuts obtained from Aboriginals at [[Buderim]].<ref>"Nut Growing Experiments", ''The Queenslander'', 8 October 1931, p. 13</ref> 
;1882
:[[William H. Purvis]] introduced macadamia nuts to Hawaii as a [[windbreak]] for sugar cane.<ref>{{cite book |last1=Hamilton |first1=Richard |url=https://www.ctahr.hawaii.edu/oc/freepubs/pdf/C1-485.pdf |title=Macadamia: Hawaii's Dessert Nut |last2=Ito |first2=Philip |last3=Chia |first3=C.L. |publisher=University of Hawaii |page=3 |access-date=10 July 2017 |archive-url=https://web.archive.org/web/20161224124607/http://www.ctahr.hawaii.edu/oc/freepubs/pdf/C1-485.pdf |archive-date=24 December 2016 |url-status=live}}</ref>
;1888
:The first commercial orchard of macadamias was planted at Rous Mill, 12&nbsp;km from [[Lismore, New South Wales]], by Charles Staff.<ref>{{cite book |last1=Rosengarten |first1=Frederic Jr. |url=https://books.google.com/books?id=7CK8LFCcvtcC&q=charles+staff+macadamia&pg=PA122 |title=The Book of Edible Nuts |date=2004 |publisher=Courier Corporation |isbn=978-0-486-43499-5 |page=122 |access-date=10 July 2017 |archive-url=https://web.archive.org/web/20200901205233/https://books.google.com/books?id=7CK8LFCcvtcC&pg=PA122&lpg=PA122&dq=charles+staff+macadamia&hl=en |archive-date=1 September 2020 |url-status=live}}</ref>
;1889
:[[Joseph Maiden]], an Australian botanist, wrote, "It is well worth extensive cultivation, for the nuts are always eagerly bought."<ref>Maiden, J. H., ''The Useful Native Plants of Australia'', 1889, p40</ref>
;1910
:The Hawaiian Agricultural Experiment Station encouraged the planting of macadamias on Hawaii's [[Kona District, Hawaii|Kona District]] as a crop to supplement coffee production in the region.<ref name="rieger">Rieger, M., ''Introduction to Fruit Crops'', 2006, p. 260. {{ISBN|978-1-56022-259-0}}</ref>
;1916
:[[Thomas Petrie|Tom Petrie]] begins trial macadamia plantations in [[Maryborough, Queensland]], combining macadamia with pecans to shelter the trees.<ref>{{cite news |date=8 October 1931 |title=Nut Growing Experiments |page=13 |agency=The Queenslander}}</ref>
;1922
:Ernest van Tassel formed the Hawaiian Macadamia Nut Co. in Hawaii.<ref>{{cite book |last1=Shigeura |first1=Gordon |url=https://www.ctahr.hawaii.edu/oc/freepubs/pdf/RES-039.pdf |title=Macadamia Nuts in Hawaii: History and Production |last2=Ooka |first2=Hiroshi |date=April 1984 |publisher=University of Hawaii |page=13 |access-date=10 July 2017 |archive-url=https://web.archive.org/web/20161224160755/http://www.ctahr.hawaii.edu/oc/freepubs/pdf/RES-039.pdf |archive-date=24 December 2016 |url-status=dead}}</ref>
;1925
:Tassel leased {{convert|75|acre|ha}} on Round Top in Honolulu and began Nutridge, Hawaii's first macadamia seed farm.<ref>{{Cite book |last=Gordon T. Shigeura and Hiroshi Ooka |title=Macadamia Nuts in Hawaii: History and Production}}</ref>
;1931
:Tassel established a macadamia-processing factory on Puhukaina Street in [[Kakaako|Kakaako, Hawaii]], selling the nuts as Van's Macadamia Nuts.
;1937
:Winston Jones and J. H. Beaumont of the [[University of Hawaii|University of Hawaii's]] Agricultural Experiment Station reported the first successful grafting of macadamias, paving the way for mass production.<ref>{{cite journal |last1=Jones |first1=Winston |last2=Beaumont |first2=J.H. |date=1 October 1937 |title=Carbohydrate accumulation in relation to vegetative propagation of the litchi |journal=Science |volume=86 |issue=#2231 |page=313 |bibcode=1937Sci....86..313J |doi=10.1126/science.86.2231.313 |pmid=17794458}}</ref>
;1946
:A large plantation was established in Hawaii.<ref>{{cite book |author=Sandra Wagner-Wright |url=https://books.google.com/books?id=AeazAAAAIAAJ |title=History of the macadamia nut industry in Hawai'i, 1881–1981 |publisher=[[Edwin Mellen Press]] |year=1995 |isbn=978-0-7734-9097-0 |location=[[Lewiston, New York]] |access-date=27 April 2020 |archive-url=https://web.archive.org/web/20200901205243/https://books.google.com/books?id=AeazAAAAIAAJ&hl=en |archive-date=1 September 2020 |url-status=live}}</ref><ref>Mauna Loa Macadamia Nut Packaging</ref>
;1953
:[[Castle & Cooke]] 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]]'', was [[Species description|described]], being first brought to the attention of plant scientists in 1983 by Ray Jansen, a sugarcane farmer and amateur botanist from [[South Kolan]] in Central [[Queensland]].<ref>{{Cite journal |last1=Gross |first1=C. L. |last2=Weston |first2=P. H. |date=1992 |title=Macadamia jansenii (Proteaceae), a new species from central Queensland |url=https://www.publish.csiro.au/sb/sb9920725 |journal=Australian Systematic Botany |language=en |volume=5 |issue=6 |pages=725–728 |doi=10.1071/sb9920725 |bibcode=1992AuSyB...5..725G |issn=1446-5701|url-access=subscription }}</ref>
;1997
:Australia surpassed the United States as the major producer of macadamias.<ref name="rieger" />
;2012–2015
:South Africa surpassed Australia as the largest producer of macadamias.<ref>{{cite news |title=Cracking good run for macadamia industry |url=http://www.farmersweekly.co.za/article.aspx?id=73097&h=Cracking-good-run-for-macadamia-industry/ |url-status=live |archive-url=https://web.archive.org/web/20150924010547/http://www.farmersweekly.co.za/article.aspx?id=73097&h=Cracking-good-run-for-macadamia-industry%2F |archive-date=24 September 2015 |access-date=8 June 2015 |work=Farmer's Weekly}}</ref><ref name="fp" />
;2014
:The manner in which macadamia nuts were served on [[Korean Air]] Flight 86 from [[John F. Kennedy International Airport]] in [[New York City]] led to a "[[nut rage incident]]", which gave the nuts high visibility in [[South Korea]] and marked a sharp increase in consumption there.<ref>{{cite news |last1=Taylor |first1=Adam |title=Why 'nut rage' is such a big deal in South Korea |url=https://www.washingtonpost.com/news/worldviews/wp/2014/12/12/why-nut-gate-is-such-a-big-deal-in-south-korea/ |url-status=live |archive-url=https://web.archive.org/web/20170809132058/https://www.washingtonpost.com/news/worldviews/wp/2014/12/12/why-nut-gate-is-such-a-big-deal-in-south-korea/ |archive-date=9 August 2017 |access-date=10 July 2017 |newspaper=The Washington Post}}</ref><ref>{{cite web |last1=Ahn |first1=Young-oon |date=15 December 2014 |title=Sales of macadamias soar in Korea after nut rage |url=https://www.cnbc.com/2014/12/15/sales-of-macadamias-soar-in-korea-after-nut-rage.html |url-status=live |archive-url=https://web.archive.org/web/20170809173358/https://www.cnbc.com/2014/12/15/sales-of-macadamias-soar-in-korea-after-nut-rage.html |archive-date=9 August 2017 |access-date=10 July 2017 |website=CNBC}}</ref>

== See also ==
* [[Macadamia oil]]

==References==
{{Reflist}}

==External links==
* {{Commonscat-inline}}

{{Proteaceae genera}}
{{Nuts}}
{{Taxonbar|from=Q310041}}
{{Authority control}}

[[Category:Macadamia| ]]
[[Category:New South Wales cuisine]]
[[Category:Queensland cuisine]]
[[Category:Edible nuts and seeds]]
[[Category:Endemic flora of Australia]]
[[Category:Fruit trees]]
[[Category:Hawaiian cuisine]]
[[Category:Proteaceae genera]]
[[Category:Proteales of Australia]]
[[Category:Q150 Icons]]