The Grevilleoideae are a subfamily of the plant family Proteaceae. Mainly restricted to the Southern Hemisphere, it contains around 46 genera and about 950 species. Genera include Banksia, Grevillea, and Macadamia.
Description The Grevilleoideae grow as trees, shrubs, or subshrubs. They are highly variable, making a simple, diagnostic identification key for the subfamily essentially impossible to provide. One common and fairly diagnostic characteristic is the occurrence of flowers in pairs that share a common bract. However, a few Grevilleoideae taxa do not have this property, having solitary flowers or inflorescences of unpaired flowers. In most taxa, the flowers occur in densely packed heads or spikes, and the fruit is a follicle.
Distribution and habitat Grevilleoideae are mainly a Southern Hemisphere family. The main centre of diversity is Australia, with around 700 of 950 species occurring there, and South America also contains taxa. However, the Grevilleoideae are barely present in Africa, where almost all of Proteaceae taxa belong to the subfamily Proteoideae. The lone exception and only grevilleoid in Africa is the Brabejum tree of Cape Town.
Taxonomy
The framework for classification of the Proteaceae was laid by L.A.S. Johnson and Barbara Briggs in their 1975 monograph "On the Proteaceae: the evolution and classification of a southern family". Their classification has been refined somewhat over the ensuing three decades, most notably by Peter H. Weston and Nigel Barker in 2006. The Grevilleoideae are now considered one of five subfamilies of the Proteaceae. The placement and circumscription of the Grevilleoideae in four tribes, according to Weston and Barker can be summarised as:
Tribe incertae sedis Sphalmium — Carnarvonia
Roupaleae Authority: Meisn.
incertae sedis Megahertzia — Knightia — Eucarpha — Triunia Subtribe Roupalinae L.A.S.Johnson & B.G.Briggs Roupala — Neorites — Orites Subtribe Lambertiinae (Venk.Rao) L.A.S.Johnson & B.G.Briggs Lambertia — Xylomelum Subtribe Heliciinae L.A.S.Johnson & B.G.Briggs Helicia — Hollandaea Subtribe Floydiinae L.A.S.Johnson & B.G.Briggs Darlingia — Floydia
Banksieae Authority: Rchb.
fossil form genera Banksieaeidites — Banksieaeformis — Banksieaephyllum Subtribe Musgraveinae L.A.S.Johnson & B.G.Briggs Musgravea — Austromuellera Subtribe Banksiinae L.A.S.Johnson & B.G.Briggs Banksia
Embothrieae Authority: Rchb.
Subtribe Lomatiinae L.A.S.Johnson & B.G.Briggs Lomatia Subtribe Embothriinae Endl. Embothrium — Oreocallis — Alloxylon — Telopea Subtribe Stenocarpinae L.A.S.Johnson & B.G.Briggs Stenocarpus — Strangea Subtribe Hakeinae Endl. Opisthiolepis — Buckinghamia — Hakea — Grevillea — Finschia
Macadamieae Authority: Venk.Rao
Subtribe Macadamiinae L.A.S.Johnson & B.G.Briggs Macadamia — Panopsis — Brabejum Subtribe Malagasiinae P.H.Weston & N.P.Barker Malagasia — Catalepidia Subtribe Virotiinae P.H.Weston & N.P.Barker Virotia — Athertonia — Heliciopsis Subtribe Gevuininae L.A.S.Johnson & B.G.Briggs Cardwellia — Euplassa — Gevuina — Bleasdalea — Hicksbeachia — Kermadecia
Uses
The nursery industry cultivates many Grevilleoideae species as barrier plants and for their prominent and distinctive flowers and foliage. Some species are of importance to the cut-flower industry, especially some Banksia and Dryandra species. Two species of the genus Macadamia and the Chilean species Gevuina avellana (Chilean hazel) are grown commercially for edible nuts. Chilean hazel has an acceptable frost tolerance.
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