Macadamia

Appearance

This species has dense foliage and grows up to 18 metres in height. The leaves, which have toothed margins, are 7 to 25 cm in length.

As the species name "tetraphylla" implies, it usually has four leaves more or less equally spaced around each leaf node, whereas the other main commercial species "integrifolia" has a variable leaf number but usually three.

It has long, pendant white to creamy pink to purple flowers, followed by woody, rounded fruits which are 2 to 3 cm in diameter and contain edible seeds. As one common name implies, the shell of this species is often dimpled or "rough shelled" as compared to the integrifolia, which has a smooth shell, and always white flowers.

Food

''Macadamia tetraphylla'' was the first Australian native food plant to be grown by non-indigenous Australians as a commercial crop. The first commercial plantation of macadamia trees were planted in the early 1880s by Charles Staff at Rous Mill, 12 km southeast of Lismore, New South Wales, consisting of ''M. tetraphylla''. Seedlings from the original plantation were used as rootstock for grafted modern varieties well into the 20th century. This original plantation was finally cleared and replaced with grafted modern varieties in the 1990s.

Ironically, even as the macadamia has spread worldwide in commercial agriculture, it is now listed as a vulnerable species in its native Australia due to habitat loss and degradation. The loss and impoverishment of its habitat has resulted from clearance of lowland rainforest for agriculture and urban development; invasive weeds; and poorly-designed fire management systems.