They are small to large evergreen trees growing to 6–40 feet tall. The leaves are arranged in whorls of three to six, lanceolate to obovate or elliptical in shape, 6–30 cm long and 2–13 cm broad, with an entire or spiny-serrated margin. The flowers are produced in a long slender simple raceme 5–30 cm long, the individual flowers 10–15 mm long, white to pink or purple, with four tepals. The fruit is a very hard woody globose follicle with a pointed apex, containing one or two seeds.
The genus is named after John Macadam, a colleague of botanist Ferdinand von Mueller, who first described the genus.[1] Common names include Macadamia, Macadamia nut, Queensland nut, Bush nut, Maroochi nut and bauple nut; Indigenous Australian names include gyndl, jindilli, and boombera.
Macadamia nut in its shell and a roasted nut
Nutritional qualities
Macadamias are highly nutritious nuts. They have the highest amount of beneficial monosaturated fats of any nut. They also contain 9% protein, 9% carbohydrate, 2% dietary fibre, calcium, phosphorus, potassium, sodium, selenium, iron, thiamine, riboflavin and niacin.
Skincare
Macadamia oil is prized for containing approximately 22% of the Omega-7 palmitoleic acid,[5] which makes it a botanical alternative to mink oil, which contains approximately 17%. This relatively high content of "cushiony" palmitoleic acid plus macadamia's high oxidative stability make it a desirable ingredient in cosmetics, especially skincare.
Cultivation and processing
The macadamia tree is usually propagated by grafting, and does not begin to produce commercial quantities of nuts until it is 7–10 years old, but once established, may continue bearing for over 100 years. Macadamias prefer fertile, well-drained soils, a rainfall of 1,000–2,000 mm, and temperatures not falling below 10°C (although once established they can withstand light frosts), with an optimum temperature of 25°C. The roots are shallow and trees can be blown down in storms; they are also susceptible to Phytophthora root disease.
The macadamia nut has an extremely hard shell, but can be cracked using a blunt instrument, such as a hammer or rock applied with some force to the nut sitting in a concave surface, or a custom made macadamia nutcracker can be used. Nuts of the "Arkin Papershell" variety, crack open more readily.
Cultivation and processing
The macadamia tree is usually propagated by grafting, and does not begin to produce commercial quantities of nuts until it is 7–10 years old, but once established, may continue bearing for over 100 years. Macadamias prefer fertile, well-drained soils, a rainfall of 1,000–2,000 mm, and temperatures not falling below 10°C (although once established they can withstand light frosts), with an optimum temperature of 25°C. The roots are shallow and trees can be blown down in storms; they are also susceptible to Phytophthora root disease.
The macadamia nut has an extremely hard shell, but can be cracked using a blunt instrument, such as a hammer or rock applied with some force to the nut sitting in a concave surface, or a custom made macadamia nutcracker can be used. Nuts of the "Arkin Papershell" variety, crack open more readily.
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