''Grevillea diffusa'' is a species of flowering plant in the family

Proteaceae The Proteaceae form a family of flowering plants predominantly distributed in the Southern Hemisphere. The family comprises 83 genera with about 1,660 known species. Together with the Platanaceae and Nelumbonaceae, they make up the order Pro ...

and is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the

Sydney Sydney ( ) is the capital city of the state of New South Wales, and the most populous city in both Australia and Oceania. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about towards the Blue Mountain ...

region of New South Wales. It is a low, compact shrub with elliptic to linear leaves, and dark red, or dark crimson to scarlet and burgundy-coloured flowers.

Description

''Grevillea diffusa'' is compact shrub that typically grows to a height of up to but sometimes an erect shrub to . The leaves are elliptic to lance-shaped with the narrower end towards the base, or linear, long and wide, the lower surface silky-hairy and the edges curved down or rolled under. The flowers are arranged in dome-shaped to more or less spherical groups and are dark red, dark crimson to burgundy-coloured or scarlet, depending on subspecies. The

pistil Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

is usually long and the style strongly curved and more or less glabrous. Flowering occurs from July to November and the fruit is a glabrous follicle.

Taxonomy

''Grevillea diffusa'' was first formally described in 1827 by Kurt Polycarp Joachim Sprengel in ''

Systema Vegetabilium ''Systema Vegetabilium'' (abbreviated as Syst. Veg.) is a book published in four editions, following twelve earlier editions known as '' Systema Naturae''. The first edition, published in 1774 and edited by Johan Andreas Murray is counted as editi ...

'' from an unpublished description by Sieber. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

(''diffusa'') means "spread out". In 1986, Donald McGillivray described subspecies of ''G. diffusa'' in his book ''New Names in Grevillea (Proteaceae)'', and in 2000

Robert Owen Makinson Robert Owen Makinson (born 1956) is an Australian botanist. He has published some 65 botanical names. See also Taxa named by Robert Owen Makinson. He studied at Macquarie University, was ABLO at Kew in 1995–1996 (replacing Barry Conn Bar ...

described subspecies in '' Flora of Australia'', and the following three names are accepted by the

Australian Plant Census The Australian Plant Census (APC) provides an online interface to currently accepted, published, scientific names of the vascular flora of Australia, as one of the output interfaces of the national government Integrated Biodiversity Information Syst ...

: * ''Grevillea diffusa'' subsp. ''constablei'' Makinson has narrowly elliptic to more or less linear leaves mostly long and wide, peduncles less than long and dark crimson to dark burgundy-coloured flowers; * ''Grevillea diffusa'' Sieber ex Spreng. subsp. ''diffusa'' has elliptic leaves long and wide, peduncles up to long and dark red flowers; * ''Grevillea diffusa'' subsp. ''filipendula'' McGill. has narrowly elliptic to more or less linear leaves mostly long and wide, peduncles long and scarlet to light burgundy-coloured flowers.

Distribution and habitat

This grevillea grows in forest or woodland, occasionally in swampy heath and is restricted to Hawkesbury sandstone in the

Sydney basin The Sydney Basin is an interim Australian bioregion and is both a structural entity and a depositional area, now preserved on the east coast of New South Wales, Australia and with some of its eastern side now subsided beneath the Tasman Sea. ...

. Subspecies ''constablei'' is found south of Sydney from

Waterfall A waterfall is a point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in several wa ...

to Helensburgh and near the

Georges River The Georges River, also known as Tucoerah River, is an intermediate tide-dominated drowned valley estuary, located to the south and west of Sydney, New South Wales, Australia. The river travels for approximately in a north and then easterly ...

, subspecies ''diffusa'' from the lower Georges River to the

Illawarra The Illawarra is a coastal region in the Australian state of New South Wales, nestled between the mountains and the sea. It is situated immediately south of Sydney and north of the South Coast region. It encompasses the two cities of Wollongo ...

region and subspecies ''filipendula'' between Calga and Mount White, north of Sydney.

Conservation status

''Grevillea diffusa'' has been listed as

Least Concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

on the

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...

. Although its distribution is restricted, the population of this species is presumed to be stable and there are currently no major threats impacting it. Increased fire regimes may pose a minor threat in some areas of its distribution.

References

{{Taxonbar, from1=Q15578113, from2=Q66104345, from3=Q100453138, from4=Q66104351 diffusa Proteales of Australia Endemic flora of Australia Flora of New South Wales Plants described in 1827 Taxa named by Kurt Polycarp Joachim Sprengel