Proteaceae is the genus

there are 62 kinds of trees and shrubs in the macadamia family

Queensland Nut    The macadamia nut originated in the coastal rain forest and scrubland of Queensland and northeastern Australia.   The nuts hang in clusters of a dozen or more.  The shell is extremely hard.  The trees bear continuously.  

Hawaii Macadamias    The Kakea, Ikaiki, Wailua, and Nuuanu are all Hawaiian hybrid varieties.  Each is a prized kernel for delicious eating and gifting. 

Finschia

Seven kinds of edible nuts grown from New Guinea to the Solomon Islands and New Hebrides are members of the macadamia nut family.   They are known as Finschia and are often planted near villages as a food tree.  The nuts have a hard shell with a thin, soft coat and an edible kernel.

The Chile Hazel
Chilean Nut
Avellano Nut

A variety found in Chile holding a kernel much like a hazelnut in both appearance and flavor.    The tree is about 50 feet tall.  Varieties have been imported to England and Ireland and is a beautiful shade tree but little recognized for its nutmeats.  In Chile the tree is commonly found in the rain forested areas of Valdivia and Chiloe.    

Kermadecia     Closely allied to the Chilian Hazel, it includes 12 varieties of trees.  They are found in Polynesia, Fiji, and northeast Australia.

Monkey Nut
Rednut 
 Found on an 80 foot tree in New South Wales and Queensland, Australia, the Monkey Nut also known as the Rednut resembles a macadamia nut but is covered wit ha red/orange shell about 1" in diameter.  The nut is edible.
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Helicia     There are 90 varieties of the Helicia found in southeast Asia, eastern Australia, and in Indo-Malaysia.   It is not known if anybody on this planet eats the nuts but the seeds are said to be edible.  The fruit, however, surrounding the nut is said to be poisonous.  The Helicia nuts are borne on plants so obscure amidst the general luxuriance of the tropical vegetation as to be scarcely known beyond the localities where they are actually found.   For the few who have tasted and described the nuts, they seem unlikely to appeal to the civilized palate.

Wild Chestnut
Wild Almond   This nut called the WILD ALMOND is found in the extreme southwest Cape in South Africa.   It is a densely growing 25' tall shrub found alongside streams.   The seed is poisonous unless well soaked.   About 1-1/2" long, the nut can be roasted and used as a coffee.   Once the nut is steeped in water, all bitterness dissolves.  it is then boiled, roasted, and ground like coffee.