''Eremophila glabra'', commonly known as tar bush, is a plant in the figwort

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Scrophulariaceae The Scrophulariaceae are a family of flowering plants, commonly known as the figwort family. The plants are annual and perennial herbs, as well as shrubs. Flowers have bilateral (zygomorphic) or rarely radial (actinomorphic) symmetry. The Scr ...

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 ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. It is sometimes a low, ground-hugging and sometimes an erect shrub. The leaves are variable in size and shape and there is a range of flower colours. In spite of its scientific name, not all forms of the plant are

glabrous Glabrousness (from the Latin ''glaber'' meaning "bald", "hairless", "shaved", "smooth") is the technical term for a lack of hair, down, setae, trichomes or other such covering. A glabrous surface may be a natural characteristic of all or part of ...

but most have many small, raised

glands In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Structure De ...

on the stems, flowers and leaves.

Description

''Eremophila glabra'' grows to in height, sometimes a

prostrate shrub A prostrate shrub is a woody plant, most of the branches of which lie upon or just above the ground, rather than being held erect as are the branches of most trees and shrubs. Background Prostration may occur because the supporting tissues in ste ...

and sometimes erect. The leaves are arranged alternately, sometimes crowded, other times sparse, usually lance-shaped but they may also be linear to egg-shaped. They are long and wide, the end pointed and the base tapering gradually towards the stem. The leaves and stems are covered with small, raised glands. The flowers are red, orange, yellow or yellowish green, lack spots and are arranged singly or in pairs in the leaf axils on a stalk which is long. There are 5

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s which are narrow egg-shaped to triangular and of slightly differing lengths. The

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s, which give the flowers their colour are long and joined in a tube with 5 lobes at the end. The upper lobes are pointed and usually close together while the lower lip is blunt and bends backwards. There are four

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s which extend beyond the end of the petals. Flowering occurs between early autumn and summer (March to December in Australia) and is followed by fruit which are oval to almost spherical, about in diameter, glabrous, dry or fleshy and dark brown.

Taxonomy

The species was first formally described in 1810 by Robert Brown who gave it the name ''Stenochilus glaber''. The description was published in ''

Prodromus Florae Novae Hollandiae et Insulae Van Diemen ''Prodromus Florae Novae Hollandiae et Insulae Van Diemen'' (Prodromus of the Flora of New Holland and Van Diemen's Land) is a flora of Australia written by botanist Robert Brown and published in 1810. Often referred to as ''Prodromus Flora Novae ...

''. In 1921,

Carl Hansen Ostenfeld Carl Emil Hansen Ostenfeld (born Carl Emil Ostenfeld-Hansen) (3 August 1873 – 16 January 1931) was a Danish systematic botanist. He graduated from the University of Copenhagen under professor Eugenius Warming. He was a keeper at the Botan ...

changed the name to ''Eremophila glabra'', publishing the change in the journal ''Biologiske meddelelser, Kongelige Danske Videnskabernes Selskab''.

Subspecies

The following names have been 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 ...

("APC") as at April 2020: * ''Eremophila glabra'' subsp. ''albicans'' (Gand.) Chinnock; * ''Eremophila glabra'' subsp. ''carnosa'' Chinnock; *''E. glabra'' subsp. ''chlorella'' (Gand.) Chinnock; *''E. glabra'' subsp. ''elegans'' Chinnock; * ''Eremophila glabra'' (R.Br.) Ostenf. subsp. ''glabra''; *''E. glabra'' subsp. ''murrayana'' Chinnock; *''E. glabra'' subsp. ''psammophora'' Chinnock; *''E. glabra'' subsp. ''tomentosa'' Chinnock; *''E. glabra'' subsp. ''verrucosa'' Chinnock. Andrew Brown and Bevan Buirchell also recognise subspecies not yet described but given the names Arrowsmith, Beverley, Diemals, Inland, Junana, Lake King, Lake Pinjarrega, Morawa, Rason Lake, Scaddan,

South Coast South Coast is a name often given to coastal areas to the south of a geographical region or major metropolitan area. Geographical Australia *South Coast (New South Wales), the coast of New South Wales, Australia, south of Sydney * South Coast (Q ...

, Wongan Hills and York. The APC accepts the names of most of those subspecies. 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 ...

''glabra'' is a

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word meaning "smooth" or "hairless" possibly referring to the hairless ovary of this species.

Distribution and habitat

This eremophila occurs in all the mainland states of Australia. Subspecies ''glabra'' is the most widespread and it occurs in a wide range of soils and vegetation associations, although only in the drier areas of the continent.

Conservation status

The species is not threatened however subspecies ''chlorella'' is classified as "

Threatened Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of ''critical depensat ...

" by the Western Australian Government Department of Parks and Wildlife meaning that it is rare and in need of protection.

Use in horticulture

Tar bush is one of the most variable species in the genus and the use of a number in one garden can give the impression of many different species. Most forms do not need a lot of maintenance apart from the occasional watering and light pruning. Propagation from seed is difficult but cuttings strike readily and preserve the features of the parent plant. It will grow in most soils, and in most positions from full sun to full shade. Most forms are drought tolerant and will survive most frosts although a few with hairy leaves will not tolerate high humidity. ''Eremophila glabra'' is popular in native gardens and a number of cultivars have been developed. A yellow flowered, prostrate form called "Kalbarri Carpet" is available as is the variety "Murchison Magic", a silvery-leaved form with red flowers.

References

{{Taxonbar, from=Q5385573 Flora of New South Wales Flora of the Northern Territory Flora of Queensland Flora of South Australia Flora of Victoria (state) Eudicots of Western Australia glabra Plants described in 1810 Taxa named by Robert Brown (botanist, born 1773)