Acacia mearnsii

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Black wattle
Acacia mearnsii blossoms.jpg
On Maui
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Subfamily: Caesalpinioideae
Clade: Mimosoid clade
Genus: Acacia
Species:
A. mearnsii
Binomial name
Acacia mearnsii
Acacia mearnsiiDistMap582.png
Occurrence data from AVH
Synonyms [1]
  • Racosperma mearnsii(De Wild.) Pedley

Acacia mearnsii, commonly known as black wattle, late black wattle or green wattle, [2] is a species of flowering plant in the family Fabaceae and is endemic to south-eastern Australia. It is usually an erect tree with smooth bark, bipinnate leaves and spherical heads of fragrant pale yellow or cream-coloured flowers followed by black to reddish brown pods. In some other parts of the world, it is regarded as an invasive species.

Contents

Description

Acacis mearnsii is a spreading shrub or erect tree that typically grows to a height of 10 m (33 ft) and has smooth bark, sometimes corrugated at the base of old specimens. The leaves are bipinnate with 7 to 31 pairs of pinnae, each with 25 to 78 pairs of pinnules. There is a spherical gland up to 8 mm (0.31 in) below the lowest pair of pinnae. The scented flowers are arranged in spherical heads of 20 to 40, pale yellow or cream-coloured, with the heads on hairy peduncles 2–8 mm (0.08–0.31 in) long. Flowering mainly occurs from October to December and black to reddish-brown pods, 30–150 mm (1.2–5.9 in) long and 4.5–8 mm (0.18–0.31 in) wide develop from October to February. [2] [3] [4]

Taxonomy

Belgian naturalist Émile Auguste Joseph De Wildeman described the black wattle in 1925 in his book Plantae Bequaertianae. [5] The species is named after American naturalist Edgar Alexander Mearns, who collected the type from a cultivated specimen in East Africa. [6] Along with other bipinnate wattles, it 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 mearnsii appears to be most closely related to A. dealbata , A. nanodealbata and A. baileyana . [7]

Distribution and habitat

A. mearnsii is native to south-eastern Australia and Tasmania, but has been introduced to North America, South America, Asia, Europe, Pacific and Indian Ocean islands, Africa, and New Zealand. [8] [9] [10] [11] [12] In these areas it is often used as a commercial source of tannin or a source of firewood for local communities.

In some regions, introduced plants of this species are considered a weed. This is because they threaten native habitats by competing with indigenous vegetation, replacing grass communities, reducing native biodiversity and increasing water loss from riparian zones. In Africa, A. mearnsii competes with local vegetation for nitrogen and water resources, which are particularly scarce in certain regions, endangering the livelihoods of millions of people. [13]

In its native range A. mearnsii is a tree of tall woodland and forests in subtropical and warm temperate regions. In Africa the species grows in disturbed areas, range/grasslands, riparian zones, urban areas, water courses, and mesic habitats at an altitude of between 600 and 1,700 metres (2,000 and 5,600 ft). In Africa it grows in a range of climates including warm temperate dry climates and moist tropical climates. A. mearnsii is reported to tolerate an annual precipitation of between 66 and 228 cm (26 and 90 in), an annual mean temperature of 14.7 to 27.8 °C (58.5 to 82.0 °F), and a pH of 5.0–7.2. [14] A. mearnsii does not grow well on very dry and poor soils. [15]

Ecology in Australia

A. mearnsii plays an important role in the native ecosystem of Australia. As a pioneer plant it quickly binds the erosion-prone soil following the bushfires that are common in its Australian habitats. Like other leguminous plants, it fixes atmospheric nitrogen in the soil. Other woodland species can rapidly use these increased nitrogen levels provided by the nodules of bacteria present in their expansive root systems. Hence they play a critical part in the natural regeneration of Australian bushland after fires.

Acacia mearnsii seed pods Starr 050816-7454 Acacia mearnsii.jpg
Acacia mearnsii seed pods

Mycorrhizal fungi attach to the roots to produce food for marsupial animals, and these animals in turn disperse the spores in their droppings to perpetuate the symbiotic relationship between the wattle's roots and mycorrhizal fungi.

The cracks and crevices in the wattle's bark are home for many insects and invertebrates. The rare Tasmanian hairstreak butterfly lays her eggs in these cracks, which hatch to produce caterpillar larva attended by ants ( Iridomyrmex sp.) that feed off the sweet exudates from the larva.[ citation needed ]A. mearnsii is used similarly as a larval host plant and food source by the imperial hairstreak, Jalmenus evagoras . [20]

The tree is home to various grubs, such as wood moths, which provide a food source to black cockatoos, which strip the bark for access to these borers.

During winter insects, birds and marsupials are hosted by the black wattle with the aid of their supplies of nectar in their leaf axials. These creatures provide an important predatory role to deal with tree dieback caused by scarab beetles and pasture pests.

Black wattles, along with gums, native box and native hop form the framework vegetation on so-called "hill-topping" sites. They are often constitute isolated remnant pockets of native vegetation amongst a lower sea of exotic pasture. These "hill-topping" sites are critical habitat for male butterflies to attract females for mating, which then lay their eggs under the wattle's bark elsewhere but still within close proximity. It's the only acceptable mating site in the area for these butterflies.

Black wattle flowers provide very nitrogen-rich pollen with no nectar. They attract pollen-feeding birds, such as wattlebirds, yellow-throated honeyeaters and New Holland honeyeaters. The protein-rich nectar in the leaf axials is very sustaining for nurturing the growth of juvenile nestlings and young invertebrates, e.g. ants.

Ants harvest the seed, attracted by the fleshy, oil-rich elaiosome (or seed stalk), which they bury and store in widely dispersed locations. These seeds are buried ready for germinating with the next soaking rains. However, a "wattle seed-eating insect" which enjoys liquid meals using its proboscis-like injector to pierce the testa and suck out the embryo, often reduces the seed's viability. [21]

Status as an invasive species

In some parts of the world, A. mearnsii is considered to be an invasive species. Its invasiveness is due to its production of large numbers of seeds each year and to its large crown that shades other species. [22]

In South Africa it is listed as a Category 2 invader in the National Environmental Biodiversity Management Act. This means a permit is required to handle a species and ensure it does not spread beyond the area of the permit. [23]

Uses

The Ngunnawal people of the Australian Capital Territory use the gum as food and to make cement (when mixed with ash), and to ensure a supply of sap, the bark was cut in the autumn. [24] The bark was also used to make coarse rope and string, and used to be infused in water to make a medicine for indigestion. [24]

Reproduction

A. mearnsii produces copious numbers of small seeds that are not dispersed actively. The species may resprout from basal shoots following a fire. [8] It also generates numerous suckers that result in thickets consisting of clones. [8] Seeds may remain viable for up to 50 years. [25]

Chemistry

Leuco-fisetinidin, a flavan-3,4-diol (leucoanthocyanidin) and a monomer of the condensed tannins called profisetinidins, can be extracted from the heartwood of A. mearnsii. [26]

Related Research Articles

<i>Acacia sensu lato</i> Genus of legumes

Acacia s.l., known commonly as mimosa, acacia, thorntree or wattle, is a polyphyletic genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae. It was described by the Swedish botanist Carl Linnaeus in 1773 based on the African species Acacia nilotica. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not. All species are pod-bearing, with sap and leaves often bearing large amounts of tannins and condensed tannins that historically found use as pharmaceuticals and preservatives.

<i>Robinia pseudoacacia</i> Species of tree native to North America

Robinia pseudoacacia, commonly known in its native territory as black locust, is a medium-sized hardwood deciduous tree, belonging to the tribe Robinieae of the legume family Fabaceae. It is native to a few small areas of the United States, but it has been widely planted and naturalized elsewhere in temperate North America, Europe, Southern Africa and Asia and is considered an invasive species in some areas, such as the temperate east coast of Australia where the cultivar "Frisia" was widely planted as a street tree before being classed as a weed. Another common name is false acacia, a literal translation of the specific name.

<i>Acacia pycnantha</i> Golden wattle of southeastern Australia

Acacia pycnantha, most commonly known as the golden wattle, is a tree of the family Fabaceae. It grows to a height of 8 metres and has phyllodes instead of true leaves. The profuse fragrant, golden flowers appear in late winter and spring, followed by long seed pods. Explorer Thomas Mitchell collected the type specimen, from which George Bentham wrote the species description in 1842. The species is native to southeastern Australia as an understorey plant in eucalyptus forest. Plants are cross-pollinated by several species of honeyeater and thornbill, which visit nectaries on the phyllodes and brush against flowers, transferring pollen between them.

<i>Acacia saligna</i> Species of plant in the family Fabaceae native to Australia

Acacia saligna, commonly known by various names including coojong, golden wreath wattle, orange wattle, blue-leafed wattle, Western Australian golden wattle, and, in Africa, Port Jackson willow, is a small tree in the family Fabaceae. Native to Australia, it is widely distributed throughout the south west corner of Western Australia, extending north as far as the Murchison River, and east to Israelite Bay. The Noongar peoples know the tree as Cujong.

<i>Acacia</i> Genus of plants

Acacia, commonly known as wattles or acacias, is a genus of about 1,084 species of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa, South America, and Australasia, but is now reserved for species mainly from Australia, with others from New Guinea, Southeast Asia, and the Indian Ocean. The genus name is Neo-Latin, borrowed from the Greek ἀκακία, a term used in antiquity to describe a preparation extracted from Vachellia nilotica, the original type species.

<span class="mw-page-title-main">Wattleseed</span> Acacia seeds eaten by Aboriginal Australians

Wattleseeds are the edible seeds from any of 120 species of Australian Acacia that were traditionally used as food by Aboriginal Australians, and eaten either green or dried to make a type of bush bread. Acacia murrayana and A. victoriae have been studied as candidates for commercial production.

<i>Acacia melanoxylon</i> Species of legume

Acacia melanoxylon, commonly known as the Australian blackwood, is an Acacia species native to south-eastern Australia. The species is also known as blackwood, hickory, mudgerabah, Tasmanian blackwood, or blackwood acacia. The tree belongs to the Plurinerves section of Acacia and is one of the most wide-ranging tree species in eastern Australia and is quite variable mostly in the size and shape of the phyllodes.

<i>Acacia implexa</i> Species of plant

Acacia implexa, commonly known as lightwood or hickory wattle, is a fast-growing Australian tree, the timber of which is used for furniture making. The wood is prized for its finish and strength. The foliage was used to make pulp and dye cloth.

<i>Acacia dealbata</i> Species of flowering plant

Acacia dealbata, the silver wattle, blue wattle or mimosa, 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.

<span class="mw-page-title-main">Black wattle</span> Index of plants with the same common name

Black wattle is the common name for a number of species of trees that are native to Australia, as listed below:

<i>Acacia parramattensis</i> Species of legume

Acacia parramattensis, commonly known as Parramatta wattle, is a tree of the family Fabaceae native to the Blue Mountains and surrounding regions of New South Wales. It is a tall shrub or tree to about 15 m (49 ft) in height with phyllodes instead of true leaves. These are finely divided bipinnate. The yellow flowers appear over summer. It generally grows in woodland or dry sclerophyll forest on alluvial or shale-based soils, generally with some clay content.

<i>Acacia salicina</i> Species of plant

Acacia salicina is a thornless species of Acacia native to Australia. It is a large shrub or small evergreen tree growing up to 13.7 m tall. It is a fast grower, dropping lots of leaf litter, with a life span of about 10–50 years. In its native range, A. salicina flowers from February to June. In the Northern Hemisphere, A. salicina flowers primarily from October to January and the seed pods are often visible from April to July. The tree's seeds are shiny, black and have a crimson appendage-like aril. A. salicina is "closely related" to Acacia ligulata and Acacia bivenosa.

<i>Acacia decurrens</i> Species of legume

Acacia decurrens, commonly known as black wattle or early green wattle, is a perennial tree or shrub native to eastern New South Wales, including Sydney, the Greater Blue Mountains Area, the Hunter Region, and southwest to the Australian Capital Territory. It grows to a height of 2–15 m (7–50 ft) and it flowers from July to September.

<i>Acacia falcata</i> Species of legume

Acacia falcata, commonly known as sickle wattle and by other vernacular names including sally, is a perennial shrub or tree native to eastern Australia, which reaches five metres in height and has cream flowers in early winter. It gets its common and scientific name for its sickle-shaped leaves. Hardy and adaptable to cultivation, it is used in regeneration of bushland.

<i>Acacia blayana</i> Species of legume

Acacia blayana, commonly known as Blay's wattle or Brogo wattle, is a tree of the genus Acacia that is native to south eastern Australia.

<i>Acacia flavescens</i> Species of legume

Acacia flavescens, also known as the red wattle, yellow wattle or primrose ball wattle, is a tree in the genus Acacia native to eastern Australia.

<i>Acacia pubescens</i> Species of legume

Acacia pubescens, also known as the downy wattle, is a species of wattle found in the Sydney Basin in eastern New South Wales. The downy wattle is classified as vulnerable; much of its habitat has vanished with the growth of the city of Sydney. As with all wattles, it has compound (pinnate) leaf stems.

<i>Acacia shirleyi</i> Species of legume

Acacia shirleyi, known colloquially as lancewood, is a species of Acacia native to Queensland and the Northern Territory in Australia. It grows as a tree to 15 metres (49 ft) high, with dark grey or black stringy bark and blue-grey foliage. The yellow flowers appear from March to July. It grows in dry scrub, open forest or mixed savannah woodland. Indigenous people used the wood as fuel and to make hunting spears. Cattle can eat the foliage as fodder.

<i>Acacia doratoxylon</i> Species of plant

Acacia doratoxylon, commonly known as currawang, lancewood, spearwood or coast myall, is a shrub or tree belonging to the genus Acacia and the subgenus Juliflorae that is native to eastern and south eastern Australia.

<i>Acacia oraria</i> Species of legume

Acacia oraria, also commonly known as coastal wattle, is a shrub of the genus Acacia and the subgenus Plurinerves that is endemic to an area along the northeastern coast of Australia and on the islands of Flores and Timor.

References

  1. 1 2 "Acacia mearnsii". Australian Plant Census. Retrieved 26 September 2020.
  2. 1 2 Kodela, Phillip G. "Acacia mearnsii". Australian Biological Resources Study, Department of Agriculture, Water and the Environment: Canberra. Retrieved 26 September 2020.
  3. ↑ Kodela, Phillip G. "Acacia mearnsii De Wild". Royal Botanic Garden Sydney. Retrieved 26 September 2020.
  4. ↑ "Acacia mearnsii". Royal Botanic Gardens Victoria. Retrieved 26 September 2020.
  5. ↑ "Acacia mearnsii". APNI. Retrieved 26 September 2020.
  6. ↑ Tame, Terry; Phillip Kodela; Barry Conn; Ken Hill (June 2001). "WattleWeb – Acacia mearnsii". Royal Botanic Gardens Sydney. Archived from the original on 10 July 2009. Retrieved 21 October 2008.
  7. ↑ 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.
  8. 1 2 3 PIER, 2003. Pacific Island Ecosystems at Risk web
  9. ↑ Adair, R. (2002). Black Wattle: South Africa Manages Conflict of Interest. CABI Biocontrol News March 2002, Volume 23 No. 1. web Archived 4 April 2005 at the Wayback Machine
  10. ↑ Paiva, J. 1999. Acacia. In Talavera, S. Aedo, C, Castroviejo, S, Romero Zarco, C, Sáez, L, Salgueiro, F.J & Velayos, (ed). Flora Iberica – Plantas Vasculares de la Península Ibérica e Islas Baleares. Vol.VII(I). Leguminosae. Real Jardín Botánico, CSIS. Madrid. ISBN   84-00-06221-3. pp. 11- 25.
  11. ↑ Franco, J.A. 1971. Nova Flora de Portugal (Continente e Açores). Vol. 1. Franco, J.A. (Ed.). Lisboa.
  12. ↑ Tutin, T. G., Heywood, V.H., Burges, N.A., Moore, D.M., Valentine, D.H., Walters, S.M. & Webb, D.A. 1992. Flora Europaea. Vol.2 Rosaceae to Umbelliferae. (reprint). Cambridge University Press. Cambridge. ISBN   0-521-06662-X, pp. 84–85
  13. ↑ Jose, Shibu; Singh, Harminder Pal; Batish, Daizy Rani; Kohli, Ravinder Kumar (2013). Invasive Plant Ecology. CRC Press. p. 2. ISBN   978-1-4398-8126-2.
  14. ↑ Duke, J. A. 1983. Acacia mearnsii. Handbook of Energy Crops. Unpublished. web
  15. ↑ Franco, J.A. 1943. Dendrologia Florestal. Lisboa.
  16. ↑ Carr, G. D. Acacia mearnsii University of Hawaii, Botany Department. web
  17. ↑ Milton, S.J., Dean W.R.J. and Richardson, D.M. 2003. Economic Incentives for Restoring Natural Capital in Southern African Rangelands, Front Ecol Environ+C26 1 (5): 247,254.
  18. ↑ Sankaran, K. V. (2002). Black Wattle Problem Emerges in Indian Forests. CABI Biocontrol News March 2002 23(1) web page (archived 2005)
  19. 1 2 De Wit, M.P., Crookes, D.J. and Van Wilgen, B.W. 2001. Conflicts of Interest in Environmental Management: Estimating the Costs and Benefits of a Tree Invasion, Biological Invasions: 3 167 – 178.
  20. ↑ Biology of Australian butterflies. Kitching, R. L. (Roger Laurence), 1945-, CSIRO (Australia). Collingwood, VIC, Australia: CSIRO Pub. 1999. ISBN   978-0643050273. OCLC   40792921.{{cite book}}: CS1 maint: others (link)
  21. ↑ Australian Plants Society (Tasmania), June 2000
  22. ↑ "Acacia mearnsii". Global Invasive Species Database. Retrieved 26 September 2020.
  23. ↑ "South African Government Gazette: Number 37320" (PDF). South Africa Government Gazette. 584: 8.
  24. 1 2 Ngunnawal Elders (2014) 'Ngunnawal Plant Use.' ACT Government: Canberra
  25. ↑ "Alien Invader Plants". 2002. Archived from the original on 24 October 2009. Retrieved 22 October 2008.
  26. ↑ Roux, D. G.; Paulus, E. (1962). "Condensed tannis. 12. Polymeric leucofisetinidin tannins from the heartwood of Acacia mearnsii". The Biochemical Journal. 82 (2): 320–324. doi:10.1042/bj0820320. PMC   1243455 . PMID   14494576.
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