|Macadamia subsp. var.||Macadamia|
Macadamia is a genus of nine species of flowering plants in the family Proteaceae, with a disjunct distribution native to eastern Australia (seven species), New Caledonia (one species M. neurophylla) and Sulawesi in Indonesia (one species, M. hildebrandii).
They are small to large evergreen trees growing to 2–12 m 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. Common names include Macadamia, Macadamia nut, Queensland nut, Bush nut, Maroochi nut, Queen of Nuts and bauple nut; Indigenous Australian names include gyndl, jindilli, and boombera.
|Standard Cyclopedia of Horticulture|
Macadamia (after John Macadam, M.D., secretary Philosophical Institute, Victoria, Australia). Proteaceae?. A small group of Australian trees or tall shrubs, of which M. ternifolia is cultivated for its edible fruit, and is the best known.
Leaves verticillate, entire or serrate: fls. hermaphrodite, pedicellate in pairs or scattered, in terminal or axillary racemes or panicles; perianth regular or nearly so; stamens inserted a little below the blades, filaments short; ovary sessile, with a long straight style, ovoid or clavate at end, stigma small; ovules 2: fr. globular; seeds either solitary and globular or 2 and hemispherical; testa membranous.
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.
A M. integrifolia / M. tetraphylla hybrid commercial variety widely planted in Australia & New Zealand. Discovered by Dr. J. H. Beaumont. It has a good taste, high in oil, but not sweet. New leaves reddish, flowers 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 prodigously when well pollinated. The impressive grape-like clusters of nuts are sometimes so heavy they break the branchlet they are attached to. In commercial orchards, it has reached 18 kg of nuts per tree by 8 years old! On the downside, the nuts don't drop from the tree when ripe, and the leaves are a bit prickly when you are reaching into the interior of the tree during harvest. Beaumonts' shell is easier than most commercial varieties to open.
A pure M. tetraphylla variety from Australia, the tree is productive, and the small nut has a particularly good flavor. It is a good pollinator for Beaumont.
A South African M. integrifolia / M. tetraphylla hybrid cultivar. It has a sweet nut, which means that it has to be cooked carefully so that the sugars do not caramelise. The sweet nut does not taste good when processed, but people who eat it uncooked relish the taste. The nut has an open micropyle (hole in the shell) which lets in mould. The crack out percentage is high. Ten year old trees average 22 kgs per tree. It is a popular variety because of its pollination of Beaumont, and the yields are almost comparable.
A M. integrifolia / M. tetraphylla hybrid. A rather spreading tree. On the plus side it is high yielding (commercially, 17 kgs off a 9 year old tree has been recorded), and the nuts drop to the ground, but the nut is thick shelled, and with not much flavor.
Pests and diseases
- ↑ Mueller, F.J.H. von (1857) Account of some New Australian Plants. Transactions of the Philosophical Institute of Victoria 2: 72 Type: Macadamia ternifolia F.Muell.
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963