The Grevilleoideae are a
subfamily
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...
of the plant family
Proteaceae
The Proteaceae form a family (biology), family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genus, genera with about 1,660 known species. Australia and South Africa have the greatest concentr ...
. Mainly restricted to the
Southern Hemisphere, it contains around 46
genera
Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...
and about 950
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
. Genera include ''
Banksia'', ''
Grevillea'', and ''
Macadamia''.
Description
The Grevilleoideae grow as
tree
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...
s,
shrub
A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...
s, 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
In botany, a bract is a modified or specialized leaf, associated with a reproductive structure such as a flower, inflorescence axis or cone scale.
Bracts are usually different from foliage leaves in size, color, shape or texture. They also lo ...
. However, a few Grevilleoideae taxa do not have this property, having solitary flowers or
inflorescence
In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...
s of unpaired flowers. In most taxa, the flowers occur in densely packed heads or spikes, and the
fruit
In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering.
Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...
is a
follicle.
Distribution and habitat
Grevilleoideae are mainly a Southern Hemisphere family. The main centre of diversity is
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
, with around 700 of 950 species occurring there, and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
also contains taxa. However, the Grevilleoideae are barely present in
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
, 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
Cape Town is the legislature, legislative capital city, capital of South Africa. It is the country's oldest city and the seat of the Parliament of South Africa. Cape Town is the country's List of municipalities in South Africa, second-largest ...
.
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
or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
::::''
Sphalmium'' — ''
Carnarvonia''
Roupaleae
Authority:
Meisn.
:::
incertae sedis
or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
::::''
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.
References
{{Taxonbar, from=Q1934685
Eudicot subfamilies