Macadamia

Macadamia is a genus of four species of trees indigenous to Australia, and constituting part of the plant family Proteaceae.  They are native to north eastern New South Wales and central and south eastern Queensland. Three species of the genus are commercially important for their fruit, the macadamia nut.  The leaves are arranged in whorls of three to six, lanceolate to obovate or elliptic in shape, with an entire or spiny-serrated margin. The flowers are produced in a long, slender, simple raceme with individual flowers.  The fruit is a hard, woody, globose follicle with a pointed apex, containing one or two seeds. The nut shell (“coat”) is particularly tough, 5 times harder than hazelnut shells, and has mechanical properties similar to aluminium.