Acacia pycnantha
Golden wattle | |
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Fabales |
Family: | Fabaceae |
Subfamily: | Caesalpinioideae |
Clade: | Mimosoid clade |
Genus: | Acacia |
Species: | A. pycnantha
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Binomial name | |
Acacia pycnantha | |
Occurrence data from AVH | |
Synonyms[1] | |
Species synonymy
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Acacia pycnantha, most commonly known as the golden wattle, is a tree of the family
A. pycnantha has become a weed in areas of Australia, as well as in Africa and Eurasia. Its bark produces more tannin than any other wattle species, resulting in its commercial cultivation for production of this compound. It has been widely grown as an ornamental garden plant and for cut flower production. A. pycnantha was made the official floral emblem of Australia in 1988, and has been featured on the country's postal stamps.
Description
Acacia pycnantha generally grows as a small tree to between 3 and 8 metres (10 and 30 feet) in height,[2] though trees of up to 12 m (40 ft) high have been reported in Morocco.[3] The bark is generally dark brown to grey—smooth in younger plants though it can be furrowed and rough in older plants.[4] Branchlets may be bare and smooth or covered with a white bloom.[2] The mature trees do not have true leaves but have phyllodes—flat and widened leaf stems—that hang down from the branches. Shiny and dark green, these are between 9 and 15 cm (3+1⁄2 and 6 in) long, 1–3.5 cm (1⁄2–1+1⁄2 in) wide and falcate (sickle-shaped) to oblanceolate in shape.[2] New growth has a bronze colouration.[5] Field observations at Hale Conservation Park show the bulk of new growth to take place over spring and summer from October to January.[6]
Floral buds are produced year-round on the tips of new growth, but only those initiated between November and May go on to flower several months later. Flowering usually takes place from July to November (late winter to early summer) in the golden wattle's native range; because the later buds develop faster, flowering peaks over July and August.[7][8] The bright yellow inflorescences occur in groups of 40 to 80 on 2.5–9 cm (1–3+1⁄2 in)-long racemes that arise from axillary buds.[2] Each inflorescence is a ball-like structure that is covered by 40 to 100 small flowers that have five tiny petals (pentamerous) and long erect stamens, which give the flower head a fluffy appearance.[4]
Developing after flowering has finished, the seed pods are flattish, straight or slightly curved, 5–14 cm (2–5+1⁄2 in) long and 5–8 mm wide.[8][9] They are initially bright green, maturing to dark brown and have slight constrictions between the seeds,[10] which are arranged in a line in the pod.[8] The oblong seeds themselves are 5.5 to 6 mm long, black and shiny, with a clavate (club-shaped) aril.[2] They are released in December and January, when the pods are fully ripe.[7]
Similar species
Species similar in appearance include mountain hickory wattle (A. obliquinervia), coast golden wattle (A. leiophylla) and golden wreath wattle (A. saligna).[2] Acacia obliquinervia has grey-green phyllodes, fewer flowers in its flower heads, and broader (1.25–2.5 cm (1⁄2–1 in)-wide) seed pods.[11] A. leiophylla has paler phyllodes.[12] A. saligna has longer, narrower phyllodes.[4]
Taxonomy
Acacia pycnantha was first formally
Johann Georg Christian Lehmann described Acacia petiolaris in 1851 from a plant grown at Hamburg Botanic Gardens from seed said to be from the Swan River Colony (Perth).[14] Carl Meissner described A. falcinella from material from Port Lincoln in 1855. Bentham classified both as A. pycnantha in his 1864 Flora Australiensis, though he did categorise a possible subspecies angustifolia based on material from Spencer Gulf with narrower phyllodes and fewer inflorescences.[17] However, no subspecies are currently recognised, though an informal classification distinguishes wetland and dryland forms, the latter with narrower phyllodes.[18]
In 1921 Joseph Maiden described Acacia westonii from the northern and western slopes of Mount Jerrabomberra near Queanbeyan in New South Wales. He felt it was similar to, but distinct from, A. pycnantha and was uncertain whether it warranted species rank. His colleague Richard Hind Cambage grew seedlings and reported they had much longer internodes than those of A. pycnantha, and that the phyllodes appeared to have three nectaries rather than the single one of the latter species.[19] It is now regarded as a synonym of A. pycnantha.[1]
Common names recorded include golden wattle, green wattle, black wattle, and broad-leaved wattle.[1] At Ebenezer Mission in the Wergaia country of north-western Victoria the Aboriginal people referred to it as witch.[20][21]
Hybrids of the species are known in nature and cultivation. In the Whipstick forest near Bendigo in Victoria, putative hybrids with Whirrakee wattle (Acacia williamsonii) have been identified; these resemble hakea wattle (Acacia hakeoides).[2] Garden hybrids with Queensland silver wattle (Acacia podalyriifolia) raised in Europe have been given the names Acacia x siebertiana and Acacia x deneufvillei.[1]
Distribution and habitat
Golden wattle occurs in south-eastern Australia from South Australia's southern Eyre Peninsula and Flinders Ranges across Victoria and northwards into inland areas of southern New South Wales and the Australian Capital Territory.[8][22] It is found in the understorey of open eucalypt forests on dry, shallow soils.[9]
The species has become naturalised beyond its original range in Australia. In New South Wales it is especially prevalent around Sydney and the Central Coast region. In Tasmania it has spread in the east of the state and become weedy in bushland near Hobart. In Western Australia, it is found in the Darling Range and western wheatbelt as well as Esperance and Kalgoorlie.[4]
Outside Australia it has become naturalised in South Africa, Tanzania, Italy, Portugal, Sardinia, India, Indonesia and New Zealand.
Ecology
Though plants are usually killed by a severe fire, mature specimens are able to resprout.[28][29] Seeds are able to persist in the soil for more than five years, germinating after fire.[29]
Like other wattles, Acacia pycnantha fixes nitrogen from the atmosphere.[30] It hosts bacteria known as rhizobia that form root nodules, where they make nitrogen available in organic form and thus help the plant grow in poor soils. A field study across Australia and South Africa found that the microbes are genetically diverse, belonging to various strains of the species Bradyrhizobium japonicum and genus Burkholderia in both countries. It is unclear whether the golden wattle was accompanied by the bacteria to the African continent or encountered new populations there.[31]
The wood serves as food for larvae of the jewel beetle species Agrilus assimilis, A. australasiae and A. hypoleucus.[36] The larvae of a number of butterfly species feed on the foliage including the fiery jewel, icilius blue, lithocroa blue and wattle blue.[37] Trichilogaster wasps form galls in the flowerheads, disrupting seed set[38] and
Cultivation
Golden wattle is cultivated in Australia and was introduced to the northern hemisphere in the mid-1800s. Although it has a relatively short lifespan of 15 to 30 years, it is widely grown for its bright yellow, fragrant flowers.[15][38] As well as being an ornamental plant, it has been used as a windbreak or in controlling erosion. Trees are sometimes planted with the taller sugar gum (Eucalyptus cladocalyx) to make a two-layered windbreak.[3] One form widely cultivated was originally collected on Mount Arapiles in western Victoria. It is floriferous, with fragrant flowers appearing from April to July.[43] The species has a degree of frost tolerance and is adaptable to a wide range of soil conditions, but it prefers good drainage.[43] It tolerates heavy soils in dry climates,[44] as well as mild soil salinity.[45] It can suffer yellowing (chlorosis) in limestone-based (alkaline) soils.[3] Highly drought-tolerant, it needs 370–550 mm (10–20 in) winter rainfall for cultivation.[3] It is vulnerable to gall attack in cultivation.[46] Propagation is from seed which has been pre-soaked in hot water to soften the hard seed coating.[15]
Uses
Golden wattle has been grown in temperate regions around the world for the tannin in its bark, as it provides the highest yield of all
In culture
Although wattles, and in particular the golden wattle, have been the informal floral emblem of Australia for many years (for instance, it represented Australia on the
The
The species was depicted on a stamp captioned "wattle" as part of a 1959–60 Australian stamp set featuring Australian native flowers. In 1970, a 5c stamp labelled "Golden Wattle" was issued to complement an earlier set depicting the floral emblems of Australia. To mark Australia Day in 1990, a 41c stamp labelled "Acacia pycnantha" was issued.[15] Another stamp labelled "Golden Wattle", with a value of 70c, was issued in 2014.[51]
The 1970 Monty Python's Flying Circus Bruces sketch includes a reference, by one of the stereotyped Australian characters, to "the wattle" as being "the emblem of our land", with suggested methods of display including "stick[ing] it in a bottle or hold[ing] it in your hand" – despite the wattle prop itself being a large, forked branch with sparse patches of leaves and generic yellow flowers.
See also
References
- ^ a b c d e f g "Acacia pycnantha Benth". Australian Plant Name Index (APNI), IBIS database. Centre for Plant Biodiversity Research, Australian Government.
- ^ a b c d e f g h Kodela 2001, p. 298.
- ^ ISBN 978-92-5-101354-0.
- ^ a b c d e "Golden Wattle Acacia pycnantha". Weeds of Australia: Biosecurity Queensland Edition. Queensland Government. Archived from the original on 4 March 2016. Retrieved 31 August 2014.
- ISBN 978-0-909830-65-6.
- ^ .
- ^ .
- ^ a b c d "Acacia pycnantha Benth". PlantNET – New South Wales Flora Online. Royal Botanic Gardens & Domain Trust, Sydney Australia. Retrieved 1 September 2014.
- ^ ISBN 978-0-7270-1403-0.
- ISBN 978-0-17-007179-6.
- ^ Kodela 2001, p. 251.
- ^ Elliot & Jones 1985, p. 74.
- ^ a b Bentham, George (1842). "Notes on Mimoseae, with a Synopsis of Species". London Journal of Botany. 1: 351.
- ^ a b Kodela 2001, p. 297.
- ^ a b c d e f g h Boden, Anne (1985). "Golden Wattle: Floral Emblem of Australia". Australian National Botanic Gardens. Archived from the original on 28 August 2007. Retrieved 28 August 2007.
- doi:10.5962/p.299681.
- ^ Bentham, George (1864). "Acacia pycnantha". . Vol. 2: Leguminosae to Combretaceae. London, United Kingdom: L. Reeve & Co. p. 365.
- PMID 23482331.
- S2CID 259739003.
- ^ Maiden, Joseph Henry. Wattles and wattlebarks of New South Wales (PDF). Sydney, New South Wales: Charles Potter.
- ISBN 978-0-85575-595-9.
- ^ "Acacia pycnantha Benth". Flora of Victoria Knowledge Base. Royal Botanic Gardens Melbourne. Archived from the original on 2 September 2014. Retrieved 6 June 2014.
- ^ "Acacia pycnantha Benth". Jepson Flora Project. Retrieved 2 September 2014.
- S2CID 25527017.
- ISBN 978-0-521-87791-6.
- .
- ISBN 978-0-643-10421-1.
- ^ "Acacia pycnantha". florabank. Greening Australia. Archived from the original on 10 March 2015. Retrieved 2 September 2014.
- ^ Department of Biodiversity, Conservation and Attractions.
- ^ Greening Australia (2010). "Acacia pycnantha". Florabank. Yarralumla, Australian Capital Territory: Australian Government/Greening Australia/CSIRO. Archived from the original on 10 March 2015. Retrieved 10 October 2014.
- .
- ISSN 0022-1503.
- ^ .
- ^ Corella. Australian Bird Study Association. 1998.
- .
- ISBN 978-3-319-08410-7.
- ^ "Acacia pycnantha". Electronic Flora of South Australia Fact Sheet. State Herbarium of South Australia. Retrieved 1 September 2014.
- ^ ISBN 978-0-642-58585-1.
- ^ Old, K.M.; Vercoe, T.K.; Floyd, R.B.; Wingfield, M.J. (2002). "FAO/IPGRI Technical Guidelines for the Safe Movement of Germplasm No. 20 Acacia sp" (PDF). Food and Agriculture Organization of the United Nations/International Plant Genetic Resources Institute. p. 24. Retrieved 15 September 2014.
- ^ McAlpine, Daniel (1906). The rusts of Australia their structure, nature and classification. Department of Agriculture (Victoria). pp. 110–12.
- ^ "Uromycladium tepperianum on Acacia spp". Invasive and Emerging Fungal Pathogens – Diagnostic Fact Sheets. United States Department of Agriculture. Archived from the original on 3 September 2014. Retrieved 2 September 2014.
- .
- ^ a b Elliot & Jones 1985, p. 103.
- ^ Lothian, T.R.N. (1969). "Gardening in the Low Rainfall Regions". Australian Plants. 5 (38): 54–55, 80–95 [89].
- ^ Zwar, J. (1975). "Trees in Dry Areas". Australian Plants. 8 (64): 164–67 [165].
- ISBN 978-0-947334-08-6.
- ISBN 978-0-643-10253-8.
- ^ "Wattle uses". World Wide Wattle. Retrieved 1 September 2014.
- ^ PMID 7861255.)
{{cite journal}}
: CS1 maint: DOI inactive as of January 2024 (link - ^ Stephen, Ninian (1988). "Proclamation of Acacia pycnantha as the Floral Emblem of Australia". Australian National Botanic Gardens. Archived from the original on 5 September 2007. Retrieved 11 September 2014.
- ^ "Plant:Acacia pycnantha". Australian Plants on Stamps. Australian National. Retrieved 1 September 2014.
- ^ "The Wedding Dress: Clare Waight Keller for Givenchy". The Royal Household, UK. 19 May 2018.
Cited texts
- Elliot, Rodger W.; Jones, David L.; Blake, Trevor (1985). Encyclopaedia of Australian Plants Suitable for Cultivation. Vol. 2. Port Melbourne, Victoria: Lothian Press. ISBN 978-0-85091-143-5.
- Kodela, Phillip G. (2001). "Acacia". In Wilson, Annette; Orchard, Anthony E. (eds.). ISBN 978-0-643-06718-9.
External links
- Media related to Acacia pycnantha at Wikimedia Commons