''Acacia dealbata'', the silver wattle, blue wattle or mimosa, is a species of

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the legume family,

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

. It is native to southeastern Australia and widely introduced in other warm climates.

Description

It is a fast-growing

evergreen In botany, an evergreen is a plant which has Leaf, foliage that remains green and functional throughout the year. This contrasts with deciduous plants, which lose their foliage completely during the winter or dry season. Consisting of many diffe ...

tree or shrub growing up to 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 , occasionally up to 17 cm, in length 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

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s 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

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s.Flora of Australia Online
''Acacia dealbata''
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.

Chemistry

''A. dealbata'' has been analyzed as containing less than 0.02% alkaloids. It is known to contain enanthic (heptanoic) acid, palmic aldehyde, anisic acid,

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main compone ...

, and

phenols In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (− O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, . Phenolic compounds ar ...

. The species is not known to be poisonous to humans or livestock.

Taxonomy

Along with other bipinnate wattles, ''A. 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''. Some authorities consider ''A. dealbata'' to be a variant of '' Acacia decurrens''.

Etymology

The Latin

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''dealbata'' means "covered in a white powder". The Wiradjuri people of

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

use the name ''Giigandul'' for the species.

Subspecies

There are two

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

: *''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.

Distribution and habitat

The species is 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.

Ecology

In moist mountain areas, a white lichen can almost cover the bark, which may contribute to the descriptor "silver".

As an invasive species

In the

Western Cape The Western Cape ( ; , ) is a provinces of South Africa, province of South Africa, situated on the south-western coast of the country. It is the List of South African provinces by area, fourth largest of the nine provinces with an area of , an ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

, the species is a Category 1 weed, requiring eradication; elsewhere in South Africa it is a Category 2 weed, requiring control outside of

plantation Plantations are farms specializing in cash crops, usually mainly planting a single crop, with perhaps ancillary areas for vegetables for eating and so on. Plantations, centered on a plantation house, grow crops including cotton, cannabis, tob ...

areas. In

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, the Department of Conservation classes it as an environmental weed. Since 2013, the species has been totally prohibited in

Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...

, except the Canary Islands and the Balearic Islands. In Portugal, the species makes part of the official list of invasive species (along with other acacias). In California, the species is invasive and appears to displace many native species, also threatening the habitat of the endangered Mount Hermon June beetle.

Cultivation

''Acacia dealbata'' is widely cultivated as an

ornamental plant Ornamental plants or ''garden plants'' are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars th ...

in warm

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

regions of the world, 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, southern Africa (South Africa, Zimbabwe), the highlands of southern India, south-western China and Chile.Michail Belov

''Chileflora''. Consulted 2010, September 22.Flora Europaea
''Acacia dealbata''
/ref>Jepson Flora
''Acacia dealbata''
/ref> It is hardy down to , but does not survive prolonged frost. It prefers a sheltered position in full sun, with acid or soil pH, neutral soil. It has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

Uses

The flowers and tip shoots are harvested for use as

cut flowers Cut flowers are flowers and flower buds (often with some Plant stem, stem and leaf) that have been cut from the plant bearing it. It is removed from the plant for decorative use. Cut greens are leaves with or without stems added to the cut flow ...

, when it is known by the florist trade as "mimosa" (not to be confused with the genus of plants called '' Mimosa''). In Italy, Albania, Russia and Georgia the flowers are also frequently given to women on

International Women's Day International Women's Day (IWD) is celebrated on 8 March, commemorating women's fight for equality and liberation along with the women's rights movement. International Women's Day gives focus to issues such as gender equality, reproductive righ ...

. The essence of the flowers, called 'mimosa', or in older texts, 'cassie', is used in perfumes. The leaves are sometimes used in Indian chutney. In Australia, the

Ngunnawal The Ngunnawal people, also spelt Ngunawal, are an Aboriginal Australians, Aboriginal people of southern New South Wales and the Australian Capital Territory in Australia. Language Ngunnawal–Gundungurra language, Ngunnawal and Gundungurr ...

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.Ngunnawal Elders (2014) 'Ngunnawal Plant Use.' ACT Government: Canberra The timber is useful for

furniture Furniture refers to objects intended to support various human activities such as seating (e.g., Stool (seat), stools, chairs, and sofas), eating (table (furniture), tables), storing items, working, and sleeping (e.g., beds and hammocks). Furnitur ...

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.

In culture

''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.

Gallery

File:New growth on Acacia dealbata.jpg, New growth File:Acacia Dealbata Mimosa.jpg, In autumn in the UK with flower buds visible File:Mimosa-0001.jpg, Closeup of flowers File:Tyenna forest.jpg, With lichenous trunks in forest near

Mount Field National Park Mount Field National Park is a national park in Tasmania, Australia, 64 km northwest of Hobart, Australia, Hobart. The landscape ranges from eucalyptus temperate rainforest to alpine moorland, rising to 1,434 metres (4,705 ft) at the ...

References

{{Taxonbar, from=Q757123 dealbata Fabales of Australia Flora of New South Wales Flora of Tasmania Flora of Victoria (state) Trees of Australia