Acacia dealbata

Acacia dealbata
Foliage and flowers
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. dealbata
Binomial name
Acacia dealbata Link[1]
Occurrence data from AVH
Synonyms
Acacia decurrens var. dealbata (Link) Muller Acacia decurrens var. mollis Lindl. Acacia puberula Dehnh. Acacia derwentii Siebert & Voss Acacia decurrens var. dealbata (Link) Maiden Acacia affinis Sweet Racosperma dealbatum (Link) Pedley[2]

Acacia dealbata, the silver wattle, blue wattle^[3] or mimosa,^[4] is a species of flowering plant in the legume family Fabaceae, native to southeastern Australia in New South Wales, Victoria, Tasmania, and the Australian Capital Territory, and widely introduced in Mediterranean, warm temperate, and highland tropical landscapes.^[5]

Description

It is a fast-growing evergreen tree or shrub growing up to 30 m tall, typically a pioneer species after fire. The leaves are bipinnate, glaucous blue-green to silvery grey, and the leaves resemble those of a fern. They are 1–12 cm (occasionally to 17 cm) long and 1–11 cm broad, with 6–30 pairs of pinnae. Each pinna is divided into 10–68 pairs of leaflets, which are 0.7–6 mm long and 0.4–1 mm broad. The flowers are produced in large racemose inflorescences made up of numerous smaller globose bright yellow flowerheads of 13–42 individual flowers. The fruit is a flattened pod 2–11.5 cm long and 6–14 mm broad, containing several seeds.^[3][6] Trees generally do not live longer than 30 to 40 years, after which in the wild they are succeeded by other species where bushfires are excluded. In moist mountain areas, a white lichen can almost cover the bark, which may contribute to the descriptor "silver".^{[citation needed]} The Latin specific epithet dealbata also means "covered in a white powder".^[7] The Wiradjuri people of New South Wales use the name Giigandul for the species.^[8]

Chemistry

It has been analyzed as containing less than 0.02% alkaloids.^[9] It is known to contain enanthic (heptanoic) acid, palmic aldehyde, anisic acid, acetic acid, and phenols.^{[10][unreliable source?]}

Taxonomy

Along with other bipinnate wattles, Acacia dealbata is classified in the section Botrycephalae within the subgenus Phyllodineae in the genus Acacia. An analysis of genomic and chloroplast DNA along with morphological characters found that the section is polyphyletic, though the close relationships of many species were unable to be resolved. Acacia dealbata appears to be most closely related to A. mearnsii, A. nanodealbata and A. baileyana.^[11]

Some authorities consider A. dealbata to be a variant of Acacia decurrens.^[3]

Subspecies

There are two subspecies:^[12]

• A. dealbata subsp. dealbata. Low to moderate altitudes. Tree to 30 m; leaves mostly 5–12 cm long.
• A. dealbata subsp. subalpina Tindale & Kodela. High altitudes in the Snowy Mountains. Shrub to 5 m (rarely 10 m) tall; leaves mostly 1.5–8.5 cm long.

Cultivation

'Kambah Karpet', a cultivar discovered at the Kambah Village

Acacia dealbata is widely cultivated as an ornamental plant in warm temperate regions of the world,^[3] and is naturalised in some areas, including Sochi (Black Sea coast of Russia), southwestern Western Australia, southeastern South Australia, Norfolk Island, the Mediterranean region from Portugal to Greece and Morocco to Israel, Yalta (Crimea, Ukraine), California, Madagascar,^[13] southern Africa (South Africa, Zimbabwe), the highlands of southern India,^[5] south-western China and Chile.^{[6][14][15][16][17]} It is hardy down to −5 °C (23 °F),^[18] but does not survive prolonged frost.^[3] It prefers a sheltered position in full sun, with acid or neutral soil. It has gained the Royal Horticultural Society's Award of Garden Merit.^[18][19]

Mimosa

'Mimosa' blossoming in an urban setting in Italy

The flowers and tip shoots are harvested for use as cut flowers, when it is known by the florist trade as "mimosa" (not to be confused with the genus of plants called Mimosa). In Italy,^[20] Albania, Russia and Georgia the flowers are also frequently given to women on International Women's Day.^{[citation needed]} The essence of the flowers, called 'mimosa', or in older texts, 'cassie', is used in perfumes.^[21]

Other uses

The Ngunnawal people of the ACT and Wiradjuri people of NSW used the bark to make coarse rope and string, the resinous sap for glue or to mix with ash to make poultices, the timber for tools, and the seeds to make flour.^[22][8] The timber is useful for furniture and indoor work, but has limited uses, mainly in craft furniture and turning. It has a honey colour, often with distinctive figures like birdseye and tiger stripes. It has a medium density (540–720 kg/m³), and is similar to its close relative blackwood, but of lighter tone without the dark heartwood.^{[citation needed]}

The leaves are sometimes used in Indian chutney.^[3] Acacia dealbata is one of the most readily-available for use in Wattle Day celebrations or commercial bouquets. It is also one of a few Australian plant species symbolically commemorated in Japan, allegedly being the first plant to bloom in the aftermath of the Hiroshima atomic bomb in August 1945.^[23]

Invasive species

In South Africa, the species is a Category 1 weed in the Western Cape (requiring eradication) and Category 2 weed (requiring control outside plantation areas) elsewhere.^[24] In New Zealand the Department of Conservation class it as an environmental weed.^[25] In Spain, due to its colonizing potential and constituting a serious threat to native species, habitats or ecosystems, this species has been included in the Spanish Catalog of Invasive Exotic Species, regulated by Royal Decree 630/2013, of 2 of August, being prohibited in Spain, except the Canary Islands and the Balearic Islands, and including its introduction into the natural environment, possession, transport, traffic and commerce.^[26] In Portugal, the species makes part of the official list of invasive species (along with other Acacia species).^[27] In California, the species is invasive and appears to displace many native species, also threatening the habitat of the endangered Mount Hermon June beetle.^[28][29]

Gallery

• 
  New growth
• 
  In autumn in the UK with flower buds visible
• 
  Closeup of flowers
• 
  With lichenous trunks in forest near Mount Field National Park

See also

List of Acacia species

References

1. "Acacia dealbata". Australian Plant Name Index (APNI). Centre for Plant Biodiversity Research, Australian Government. Retrieved 15 March 2023.
2. «Acacia dealbata» EOL. Consulted on 21 November 2013.
3. Gualtiero Simonetti (1990). Stanley Schuler (ed.). Simon & Schuster's Guide to Herbs and Spices. Simon & Schuster, Inc. ISBN 978-0-671-73489-3.
4. "Acacia dealbata". RHS. Retrieved 11 December 2022.
5. Kull, Christian A.; Shackleton, Charlie M.; Cunningham, Peter J.; Ducatillon, Catherine; Dufour-Dror, Jean-Marc; Esler, Karen J.; Friday, James B.; Gouveia, António C.; Griffin, A. R.; Marchante, Elizabete; Midgley, Stephen J.; Pauchard, Aníbal; Rangan, Haripriya; Richardson, David M.; Rinaudo, Tony; Tassin, Jacques; Urgenson, Lauren S.; von Maltitz, Graham P.; Zenni, Rafael D.; Zylstra, Matthew J. (2011). "Adoption, use and perception of Australian acacias around the world". Diversity and Distributions. 17 (5): 822–836. doi:10.1111/j.1472-4642.2011.00783.x.
6. Flora of Australia Online: Acacia dealbata Archived 2021-05-02 at the Wayback Machine
7. Harrison, Lorraine (2012). RHS Latin for Gardeners. United Kingdom: Mitchell Beazley. ISBN 978-1845337315.
8. Williams, Alice; Sides, Tim, eds. (2008). Wiradjuri Plant Use in the Murrumbidgee Catchment. Murrumbidgee Catchment Management Authority. p. 19. ISBN 978-0-7347-5856-9.
9. Chemotaxonomie der Pflanzen By Robert Hegnauer
10. Mimosa Essential Oil
11. Brown, Gillian K.; Ariati, Siti R.; Murphy, Daniel J.; Miller, Joseph T. H.; Ladiges, Pauline Y. (1991). "Bipinnate acacias (Acacia subg. Phyllodineae sect. Botrycephalae) of eastern Australia are polyphyletic based on DNA sequence data". Australian Systematic Botany. 19 (4): 315–26. doi:10.1071/SB05039.
12. "Acacia dealbata Link". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 16 March 2023.
13. Kull, Christian A. (2007). "Multifunctional, Scrubby, and Invasive Forests?". Mountain Research and Development. 27 (3): 224–231. doi:10.1659/mrd.0864. S2CID 106404585.
14. Michail Belov: [1], Chileflora. Consulted 2010, September 22.
15. Flora Europaea: Acacia dealbata
16. Jepson Flora: Acacia dealbata
17. "Archived copy" (PDF). Archived from the original (PDF) on 2013-06-27. Retrieved 2013-05-02. Kull, Christian A.; Rangan, Haripriya (2008). "Acacia exchanges: Wattles, thorn trees, and the study of plant movements". Geoforum. 39 (3): 1258–1272. doi:10.1016/j.geoforum.2007.09.009.
18. "Acacia dealbata". www.rhs.org. Royal Horticultural Society. Retrieved 14 February 2020.
19. "AGM Plants - Ornamental" (PDF). www.rhs.org. Royal Horticultural Society. July 2017. p. 1. Retrieved 14 February 2020.
20. "8 Marzo, festa della donna: ecco perché si regala la mimosa". ANSA. 2015-03-06.
21. Vosnaki, Elena. "Mimosa". Fragrantica. Retrieved 16 March 2019.
22. Ngunnawal Elders (2014) 'Ngunnawal Plant Use.' ACT Government: Canberra
23. "National Wattle Day 2012". Friends of the Australian National Botanic Gardens. 6 September 2012. Retrieved 22 August 2024. Representatives of the Embassy of Japan attended in recognition of the silver wattle (Acacia dealbata) being the first plant to bloom after the devastation of Hiroshima by the atomic bomb in August 1945.
24. Invasive Species South Africa
25. Howell, Clayson (May 2008). Consolidated list of environmental weeds in New Zealand (PDF). DRDS292. Wellington: Department of Conservation. ISBN 978-0-478-14413-0. Archived from the original (PDF) on 2009-05-30. Retrieved 2009-05-06.
26. Real Decreto 630/2013, de 2 de agosto, por el que se regula el Catálogo español de especies exóticas invasoras. Boletín Oficial del Estado.
27. "Decreto-Lei 92/2019, 2019-07-10". Diário da República Eletrónico (in Portuguese).
28. DiTomaso, J. M.; Bell, C. E.; Wilen, C. A. (June 2017). "Invasive Plants". Statewide Integrated Pest Management Program. Pest Notes. Davis, California: University of California Division of Agriculture and Natural Resources. UC ANR Publication 74139. Retrieved 2021-06-09.
29. DiTomaso, Joseph M.; Williams, Andrea (2007). "Acacia dealbata Plant Assessment Form". Berkeley, California: California Invasive Plant Council. Retrieved 2021-06-09.