Eremophila glabra

Tar Bush
Eremophila glabra in Mount Annan Botanic Garden
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Lamiales
Family: Scrophulariaceae
Genus: Eremophila
Species: E. glabra
Binomial name
Eremophila glabra
(R.Br.) Ostenf.[1]
Synonyms[2]

Eremophila glabra, commonly known as tar bush, is a plant in the figwort family, Scrophulariaceae and is endemic to Australia. 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 but most have many small, raised glands on the stems, flowers and leaves.

Description

Eremophila glabra grows to 0.1–3 m (0.3–10 ft) in height, sometimes a prostrate shrub 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 7.5–61 mm (0.3–2 in) long and 0.8–18 mm (0.03–0.7 in) wide, the end pointed and the base tapering gradually towards the stem. The leaves and stems are covered with small, raised glands.[2][3]

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 3–10 mm (0.1–0.4 in) long. There are 5 sepals which are narrow egg-shaped to triangular and of slightly differing lengths. The petals, which give the flowers their colour are 20–30 mm (0.8–1 in) 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 stamens which extend beyond the end of the petals. Flowering occurs between early autumn and summer (March to December in Australia) and is followed by fruits which are oval to almost spherical, about 4–9 mm (0.2–0.4 in) in diameter, glabrous, dry or fleshy and dark brown.[2][3][4]

Eremophila glabra 'Murchison Magic' in Maranoa Gardens, Balwyn, Victoria
Eremophila glabra typical habit

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.[5][6] In 1921, Carl Hansen Ostenfeld changed the name to Eremophila glabra, publishing the change in the journal Biologiske meddelelser, Kongelige Danske Videnskabernes Selskab.[1]

Subspecies

The following subspecies have been described by Robert Chinnock, although there may be others not yet described:[2]

The specific epithet glabra is a Latin word meaning "smooth" or "hairless"[16] possibly referring to the hairless ovary of this species.[2]

Distribution and habitat

E. glabra occurs in all the mainland states of Australia. Eremophila glabra subsp. 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.[2]

Conservation

The species is not threatened however Eremophila glabra subsp. chlorella is classified as "threatened" by the Western Australian Government Department of Parks and Wildlife[4] meaning that it is rare and in need of protection.[17]

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.[18][19]

References

  1. 1 2 "Eremophila glabra". APNI. Retrieved 23 July 2015.
  2. 1 2 3 4 5 6 Chinnock, R.J. (Bob) (2007). Eremophila and allied genera : a monograph of the plant family Myoporaceae (1st ed.). Dural, NSW: Rosenberg. pp. 579–593. ISBN 9781877058165.
  3. 1 2 "Eremophila glabra (R.Br.) Ostenf.". Royal Botanic Garden Sydney: Plantnet. Retrieved 9 September 2015.
  4. 1 2 "Eremophila glabra". FloraBase. Department of Environment and Conservation, Government of Western Australia.
  5. ↑ "Stenochilus glaber". APNI. Retrieved 10 September 2015.
  6. ↑ Brown, Robert (1810). Prodromus Florae Novae Hollandiae (Volume 10) (PDF). London. p. 517. Retrieved 10 September 2015.
  7. ↑ "Eremophila glabra subsp. albicans". APNI. Retrieved 10 September 2015.
  8. ↑ "Eremophila glabra subsp. carnosa". APNI. Retrieved 10 September 2015.
  9. ↑ "Eremophila glabra subsp. chlorella". APNI. Retrieved 10 September 2015.
  10. ↑ "Eremophila glabra subsp. chlorella". APNI. Retrieved 10 September 2015.
  11. ↑ "Eremophila glabra subsp. glabra". APNI. Retrieved 24 March 2016.
  12. ↑ "Eremophila glabra subsp. murrayana". APNI. Retrieved 10 September 2015.
  13. ↑ "Eremophila glabra subsp. psammophora". APNI. Retrieved 10 September 2015.
  14. ↑ "Eremophila glabra subsp. tomentosa". APNI. Retrieved 10 September 2015.
  15. ↑ "Eremophila glabra subsp. verrucosa". APNI. Retrieved 10 September 2015.
  16. ↑ "glaber". Wiktionary. Retrieved 10 September 2015.
  17. ↑ "Conservation codes for Western Australian fauna and flora" (PDF). Western Australian Government Department of Parks and Wildlife. Retrieved 10 September 2015.
  18. ↑ "Eremophila glabra". Australian Native Plants Society Australia. Retrieved 10 September 2015.
  19. ↑ Boschen, Norma; Goods, Maree; Wait, Russell (2008). Australia's eremophilas : changing gardens for a changing climate. Melbourne: Bloomings Books. pp. 101–105. ISBN 9781876473655.
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