Acacia | |
---|---|
Acacia baileyana Canberra | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Fabales |
Family: | Fabaceae |
Subfamily: | Caesalpinioideae |
Clade: | Mimosoid clade |
Genus: | Acacia Mill. [1] |
Type species | |
Acacia penninervis | |
Species | |
Synonyms | |
Acacia, commonly known as wattles [3] [4] 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. [1] The genus name is Neo-Latin, borrowed from the Greek ἀκακία (akakia), a term used in antiquity to describe a preparation extracted from Vachellia nilotica , the original type species.
A number of species of Acacia have been introduced to various parts of the world, and two million hectares of commercial plantations have been established. [5]
Plants in the genus Acacia are shrubs or trees with bipinnate leaves, the mature leaves sometimes reduced to phyllodes or rarely absent. There are 2 small stipules at the base of the leaf, but sometimes fall off as the leaf matures. The flowers are borne in spikes or cylindrical heads, sometimes singly, in pairs or in racemes in the axils of leaves or phyllodes, sometimes in panicles on the ends of branches. Each spike or cylindrical head has many small golden-yellow to pale creamy-white flowers, each with 4 or 5 sepals and petals, more than 10 stamens, and a thread-like style that is longer than the stamens. The fruit is a variably-shaped pod, sometimes flat or cylindrical, containing seeds with a fleshy aril on the end. [6] [7] [8] [9] [10] [11]
The genus was first validly named in 1754 by Philip Miller in The Gardeners Dictionary . [12] In 1913 Nathaniel Lord Britton and Addison Brown selected Mimosa scorpioides L. (≡ Acacia scorpioides (L.) W.Wight = Acacia nilotica (L.) Delille ), a species from Africa, as the lectotype of the name.
Genus Acacia was considered to contain some 1352 species leading to 1986. That year, Leslie Pedley questioned the monophyletic nature of the genus, and proposed a split into three genera: Acacia sensu stricto (161 species), Senegalia (231 species) and Racosperma (960 species), the last name first proposed in 1829 by Carl Friedrich Philipp von Martius as the name of a section in Acacia, [13] but raised to generic rank in 1835. [14] [15] [16] In 2003, Pedley published a paper with 834 new combinations in Racosperma for species, most of which were formerly placed in Acacia. [17] All but 10 of these species are native to Australasia, where it constitutes the largest plant genus. [10]
In the early 2000s, it had become evident that the genus as it stood was not monophyletic and that several divergent lineages needed to be placed in separate genera. It turned out that one lineage comprising over 900 species mainly native to Australia, New Guinea, and Indonesia was not closely related to the much smaller group of African lineage that contained A. nilotica – the type species. This meant that the Australasian lineage (by far the most prolific in number of species) would need to be renamed. Pedley's proposed name of Racosperma for this group had received little acclaim in the botanical community. Australian botanists proposed a less disruptive solution, setting a different type species for Acacia ( A. penninervis ) and allowing this largest number of species to remain in Acacia, resulting in the two pan-tropical lineages being renamed Vachellia and Senegalia , and the two endemic American lineages renamed Acaciella and Mariosousa . [18]
In 2003, Anthony Orchard and Bruce Maslin filed a proposal to conserve the name Acacia with a different type, in order to retain the Australasian group of species in the genus Acacia. [16] Following a controversial decision to choose a new type for Acacia in 2005, the Australian component of Acacia s.l. now retains the name Acacia. [19] [20] At the 2011 International Botanical Congress held in Melbourne, Australia, the decision to use the name Acacia, rather than the proposed Racosperma for this genus, was upheld. [21] [22] Other Acacia s.l. taxa continue to be called Acacia by those who choose to consider the entire group as one genus. [22]
The Australian species of the genus Paraserianthes s.l. (namely P. lophantha) are deemed its closest relatives. [23] The nearest relatives of Acacia and Paraserianthes s.l. in turn include the Australian and South East Asian genera Archidendron , Archidendropsis , Pararchidendron and Wallaceodendron , all of the tribe Ingeae. [24]
The genus name is Neo-Latin, borrowed from the Greek akakia, a name used by Dioscorides for some prickly species growing in Egypt, from acacis meaning "a point". [25] In his Pinax (1623), Bauhin mentioned the Greek ἀκακία from Dioscorides as the origin of the Latin name. [26]
The origin of "wattle" may be an Old Teutonic word meaning "to weave". [27] From around 700 AD, watul was used in Old English to refer to the flexible woody vines, branches, and sticks which were interwoven to form walls, roofs, and fences. Since about 1810 it has been used as the common name for the Australian legume trees and shrubs that can provide these branches. [27]
There are about 1,080 species of Acacia, mostly native to Australia. [9]
An Acacia-like 14 cm (5.5 in) long fossil seed pod has been described from the Eocene of the Paris Basin. [28] Acacia-like fossil pods under the name Leguminocarpon are known from late Oligocene deposits at different sites in Hungary. Seed pod fossils of †Acacia parschlugiana and †Acacia cyclosperma are known from Tertiary deposits in Switzerland. [29] †Acacia colchica has been described from the Miocene of West Georgia. Pliocene fossil pollen of an Acacia sp. has been described from West Georgia (including Abkhazia). [30] The oldest fossil Acacia pollen in Australia are recorded as being from the late Oligocene epoch, 25 million years ago. [31]
Species of Acacia occurs in all Australian states and territories, and on its nearby islands. About 20 species occur naturally outside Australia and 7 of these also occur in Australia. One species ( Acacia koa ) is native to Hawaii [32] and one ( Acacia heterophylla ) is native to Mauritius and Réunion in the Indian Ocean. [9] [33]
They are present in all terrestrial habitats, including alpine settings, rainforests, woodlands, grasslands, coastal dunes and deserts. [11] In drier woodlands or forests they are an important component of the understory. Elsewhere they may be dominant, as in the Brigalow Belt, Myall woodlands and the eremaean Mulga woodlands. [11]
In Australia, Acacia forest is the second most common forest type after eucalypt forest, covering 980,000 square kilometres (378,380 sq mi) or 8% of total forest area. Acacia is also the nation's largest genus of flowering plants with almost 1000 species found. [34]
Acacia is a common food source and host plant for butterflies of the genus Jalmenus. The imperial hairstreak, Jalmenus evagoras, feeds on at least 25 acacia species. [35] Many reptiles feed on the sap, such as the native house gecko in Australia. [36] The sap is also consumed by bugs (Hemiptera), such as Hackerobrachys viridiventris [37] and Sextius virescens . [38]
Some species of acacia contain psychoactive alkaloids, and some contain potassium fluoroacetate. [39]
The seed pods, flowers, and young leaves are generally edible either raw or cooked. [40]
Aboriginal Australians have traditionally harvested the seeds of some species, to be ground into flour and eaten as a paste or baked into a cake. Wattleseeds contain as much as 25% more protein than common cereals, and they store well for long periods due to the hard seed coats. [41] In addition to using the edible seed and gum, the people employed the timber for implements, weapons, fuel and musical instruments. [11] A number of species, most notably Acacia mangium (hickory wattle), A. mearnsii (black wattle) and A. saligna (coojong), are economically important and are widely planted globally for wood products, tannin, firewood and fodder. [19] A. melanoxylon (blackwood) and A. aneura (mulga) supply some of the most attractive timbers in the genus. Black wattle bark supported the tanning industries of several countries, and may supply tannins for production of waterproof adhesives. [11]
In Vietnam, Acacia is used in plantations of non-native species that are regularly clear-cut for paper or timber uses. [42] [43]
Wattle bark collected in Australia in the 19th century was exported to Europe where it was used in the tanning process. One ton of wattle or mimosa bark contained about 68 kilograms (150 pounds) of pure tannin. [44]
The gum of some species may be used as a substitute for gum arabic, known as Australian gum or wattle gum. [45]
Some species of acacia – notably Acacia baileyana , A. dealbata and A. pravissima – are cultivated as ornamental garden plants. The 1889 publication Useful Native Plants of Australia describes various uses for eating. [46]
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.
The Mimosoideae are a traditional subfamily of trees, herbs, lianas, and shrubs in the pea family (Fabaceae) that mostly grow in tropical and subtropical climates. They are typically characterized by having radially symmetric flowers, with petals that are twice divided (valvate) in bud and with numerous showy, prominent stamens.
The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, are a large and agriculturally important family of flowering plants. It includes trees, shrubs, and perennial or annual herbaceous plants, which are easily recognized by their fruit (legume) and their compound, stipulate leaves. The family is widely distributed, and is the third-largest land plant family in number of species, behind only the Orchidaceae and Asteraceae, with about 765 genera and nearly 20,000 known species.
Acacia cultriformis, known as the knife-leaf wattle, dogtooth wattle, half-moon wattle or golden-glow wattle, is a perennial tree or shrub of the genus Acacia native to Australia. It is widely cultivated, and has been found to have naturalised in Asia, Africa, North America, New Zealand and South America. A. cultriformis grows to a height of about 4 m (13 ft) and has triangle-shaped phyllodes. The yellow flowers appear from August to November in its natural range. Its attractive foliage and bright flowers make it a popular garden plant.
Senegalia rugata is a spiny climbing shrub native to China and tropical Asia, common in the warm plains of central and south India. It is renowned as a raw material for shampoo, and the leaves and young shoots are often eaten. Archaeobotanical evidence shows its use for hair care in the pre-Harrapan levels of Banawali, some 4500–4300 years ago.
Acacia denticulosa, commonly known as sandpaper wattle, is a species of Acacia native to the south-west of Western Australia. A spindly shrub 1–4 m high, it flowers from September to October, producing dense, curved, yellow flower spikes.
Vachellia nilotica, more commonly known as Acacia nilotica, and by the vernacular names of gum arabic tree, babul, thorn mimosa, Egyptian acacia or thorny acacia, is a flowering tree in the family Fabaceae. It is native to Africa, the Middle East and the Indian subcontinent. It is also considered a 'weed of national significance' and an invasive species of concern in Australia, as well as a noxious weed by the federal government of the United States.
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.
Leslie Pedley was an Australian botanist who specialised in the genus Acacia. He is notable for bringing into use the generic name Racosperma, creating a split in the genus, which required some 900 Australian species to be renamed, because the type species of Acacia, Acacia nilotica, now Vachellia nilotica, had a different lineage from the Australian wattles. However, the International Botanical Congress (IBC), held in Melbourne in 2011, ratified its earlier decision to retain the name Acacia for the Australian species, but to rename the African species.
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.
Paraserianthes lophantha, the Cape Leeuwin wattle, Bicol wattle, Cape wattle, Crested wattle, Brush wattle or plume albizia, is a fast-growing tree with creamy-yellow, bottlebrush like flowers. It is the sole species in genus Paraserianthes.
Vachellia is a genus of flowering plants in the legume family, Fabaceae, commonly known as thorn trees or acacias. It belongs to the subfamily Mimosoideae. Its species were considered members of genus Acacia until 2009. Vachellia can be distinguished from other acacias by its capitate inflorescences and spinescent stipules. Before discovery of the New World, Europeans in the Mediterranean region were familiar with several species of Vachellia, which they knew as sources of medicine, and had names for them that they inherited from the Greeks and Romans.
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.
Senegalia modesta is a species of plant commonly found in Pakistan, India and Afghanistan. S. modesta is a perennial tree and formerly, it was classified as Acacia modesta. The plant is drought tolerant. S. modesta`s tree grow in medium size deciduous form with rough surfaced, brown or greenish grey bark, leaflets as, cream colored inflorescence in the form of pedunculate spike, pods as stipitate having 3-5 seeds inside.
Acacia fulva, known colloquially as velvet wattle or soft wattle, is a species of Acacia native to eastern Australia.
Acacia cana, or commonly named as boree or the cabbage-tree wattle or broad-leaved nealie, is part of the family Fabaceae and sub-family Mimosoideae. It is a dense shrub- tree that can grow to 6 metres (20 ft) high and is a perennial plant meaning it has long life span and doesn’t necessary produce a high amount of seed. The cabbage-tree wattle heavily flowers from August till October and relies on animals and insects for pollination and dispersal of seeds. This least concern acacia species is found in the western plains of New South Wales and Central Queensland the habitats of these areas are found to be sandy soils and gibber plains.
Acacia atkinsiana, commonly known as Atkin's wattle, is a shrub belonging to the genus Acacia and the subgenus Juliflorae endemic to Australia. The indigenous peoples of the area where the shrub is found, the Kurrama peoples, know the shrub as Bilari or Pilarri.
Acacia calcicola is a shrub or tree of the genus Acacia and the subgenus Plurinerves that is native to parts of central Australia. Common names for this species include; shrubby wattle, shrubby mulga, myall-gidgee, northern myall and grey myall. Indigenous Australians the Pitjantjatjara peoples know the tree as ikatuka, the Warlpiri know it as jirlarti and the Arrernte know it as irrakwetye.
Acacia simsii is a shrub belonging to the genus Acacia in the family Fabaceae. It is native to New Guinea and northern Australia. In Australia it is found in both the Northern Territory and Queensland.
Senegalia megaladena is a spiny climber, shrub or tree, native to Jawa, and from mainland Southeast Asia to China and India. It is eaten as a vegetable and used as a fish poison. It is named after its distinctive large gland on the petioles.
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