''Acacia pycnantha'', most commonly known as the golden wattle, is a tree of the family
native to southeastern Australia. It grows to a height of and has
phyllode
Phyllodes are modified petioles or leaf stems, which are leaf-like in appearance and function. In some plants, these become flattened and widened, while the leaf itself becomes reduced or vanishes altogether. Thus the phyllode comes to serve the ...
s (flattened leaf stalks) instead of true leaves.
Sickle
A sickle, bagging hook, reaping-hook or grasshook is a single-handed agricultural tool designed with variously curved blades and typically used for harvesting, or reaping, grain crops or cutting succulent forage chiefly for feeding livestock, ei ...
-shaped, these are between long, and wide. The profuse fragrant, golden flowers appear in late winter and spring, followed by long seed pods. Plants are cross-pollinated by several species of
honeyeater
The honeyeaters are a large and diverse family (biology), family, Meliphagidae, of small to medium-sized birds. The family includes the Epthianura, Australian chats, myzomelas, friarbirds, wattlebirds, Manorina, miners and melidectes. They are ...
and
thornbill, which visit
nectaries
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualist ...
on the phyllodes and brush against flowers, transferring pollen between them. An
understorey
In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abov ...
plant in
eucalyptus
''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...
forest, it is found from southern New South Wales and the Australian Capital Territory, through Victoria and into southeastern South Australia.
Explorer
Thomas Mitchell collected the
type specimen
In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...
, from which
George Bentham
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studi ...
wrote the
species description
A species description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species that have be ...
in 1842. No subspecies are recognised. The bark of ''A. pycnantha'' produces more
tannin
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.
The term ''tannin'' (from Anglo-Norman ''tanner'', ...
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, but has become a weed in South Africa, Tanzania, Italy, Portugal, Sardinia, India, Indonesia, New Zealand, as well as Western Australia, Tasmania and New South Wales. ''Acacia pycnantha'' was made the official
floral emblem of Australia in 1988, and has been featured on the country's postal stamps.
Description
![Acacia pycnantha 5145](https://upload.wikimedia.org/wikipedia/commons/4/45/Acacia_pycnantha_5145.jpg)
''Acacia pycnantha'' generally grows as a small tree to between in height, though trees of up to high have been reported in Morocco.
The bark is generally dark brown to grey—smooth in younger plants though it can be furrowed and rough in older plants.
[ Branchlets may be bare and smooth or covered with a white bloom. 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 long, wide and falcate (]sickle
A sickle, bagging hook, reaping-hook or grasshook is a single-handed agricultural tool designed with variously curved blades and typically used for harvesting, or reaping, grain crops or cutting succulent forage chiefly for feeding livestock, ei ...
-shaped) to oblanceolate
The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...
in shape. New growth has a bronze colouration. Field observations at Hale Conservation Park
Hale Conservation Park (formerly Hale National Park and Hale Wild-Life Reserve) is a protected area in the Australian state of South Australia located in the locality of Williamstown about north-east of the state capital of Adelaide and about ...
show the bulk of new growth to take place over spring and summer from October to January.
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. The bright yellow inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
s occur in groups of 40 to 80 on -long raceme
A raceme ( or ) or racemoid is an unbranched, indeterminate type of inflorescence bearing flowers having short floral stalks along the shoots that bear the flowers. The oldest flowers grow close to the base and new flowers are produced as the s ...
s that arise from axillary bud
The axillary bud (or lateral bud) is an embryonic or organogenic shoot located in the axil of a leaf. Each bud has the potential to form shoots, and may be specialized in producing either vegetative shoots (stems and branches) or reproductive sh ...
s. 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 stamen
The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10
Morphology and terminology
A stamen typically consists of a stalk called the filame ...
s, which give the flower head a fluffy appearance.[
Developing after flowering has finished, the seed pods are flattish, straight or slightly curved, long and 5–8 mm wide.] They are initially bright green, maturing to dark brown and have slight constrictions between the seeds, which are arranged in a line in the pod.[ The oblong seeds themselves are 5.5 to 6 mm long, black and shiny, with a ]clavate
This glossary of entomology describes terms used in the formal study of insect species by entomologists.
A–C
A synthetic chlorinated hydrocarbon insecticide, toxic to vertebrates. Though i ...
(club-shaped) aril
An aril (pronounced ), also called an arillus, is a specialized outgrowth from a seed that partly or completely covers the seed. An arillode or false aril is sometimes distinguished: whereas an aril grows from the attachment point of the see ...
. They are released in December and January, when the pods are fully ripe.
Species similar in appearance include mountain hickory wattle ('' A. obliquinervia''), coast golden wattle ('' A. leiophylla'') and golden wreath wattle ('' A. saligna''). ''Acacia obliquinervia'' has grey-green phyllodes, fewer flowers in its flower heads, and broader (-wide) seed pods. ''A. leiophylla'' has paler phyllodes. ''A. saligna'' has longer, narrower phyllodes.[
]
Taxonomy
''Acacia pycnantha'' was first formally described by botanist George Bentham
George Bentham (22 September 1800 – 10 September 1884) was an English botanist, described by the weed botanist Duane Isely as "the premier systematic botanist of the nineteenth century". Born into a distinguished family, he initially studi ...
in the '' London Journal of Botany'' in 1842. The type specimen
In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...
was collected by the explorer Thomas Mitchell in present-day northern Victoria
Victoria most commonly refers to:
* Victoria (Australia), a state of the Commonwealth of Australia
* Victoria, British Columbia, provincial capital of British Columbia, Canada
* Victoria (mythology), Roman goddess of Victory
* Victoria, Seychelle ...
between Pyramid Hill and the Loddon River
The Loddon River, an inland river of the northcentral catchment, part of the Murray-Darling basin, is located in the lower Riverina bioregion and Central Highlands and Loddon Mallee regions of the Australian state of Victoria. The headwater ...
. Bentham thought it was related to ''A. leiophylla'', which he described in the same paper. The specific epithet ''pycnantha'' is derived from the Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
words ' (dense) and ' (flower), a reference to the dense cluster of flowers that make up the globular inflorescences. Queensland botanist Les Pedley reclassified the species as ''Racosperma pycnanthum'' in 2003, when he proposed placing almost all Australian members of the genus into the new genus ''Racosperma
''Acacia'', commonly known as the wattles or acacias, is a large genus of shrubs and trees in the subfamily Mimosoideae of the pea family Fabaceae. Initially, it comprised a group of plant species native to Africa and Australasia. The genus na ...
''. However, this name is treated as a synonym
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
of its original name.[
]Johann Georg Christian Lehmann
Johann Georg Christian Lehmann (25 February 1792 – 12 February 1860) was a German botanist.
Born at Haselau, near Uetersen, Holstein, Lehmann studied medicine in Copenhagen and Göttingen, obtained a doctorate in medicine in 1813 and a doct ...
described ''Acacia petiolaris'' in 1851 from a plant grown at Hamburg Botanic Gardens from seed said to be from the Swan River Colony
The Swan River Colony, also known as the Swan River Settlement, or just Swan River, was a British colony established in 1829 on the Swan River, in Western Australia. This initial settlement place on the Swan River was soon named Perth, and it ...
(Perth). Carl Meissner
Carl Daniel Friedrich Meissner (1 November 1800 – 2 May 1874) was a Swiss botanist.
Biography
Born in Bern, Switzerland on 1 November 1800, he was christened Meisner but later changed the spelling of his name to Meissner. For most of his 40 ...
described ''A. falcinella'' from material from Port Lincoln in 1855. Bentham classified both as ''A. pycnantha'' in his 1864 ''Flora Australiensis
''Flora Australiensis: a description of the plants of the Australian Territory'', more commonly referred to as ''Flora Australiensis'', and also known by its standard abbreviation ''Fl. Austral.'', is a seven-volume flora of Australia published be ...
'', though he did categorise a possible subspecies ''angustifolia'' based on material from Spencer Gulf
The Spencer Gulf is the westernmost and larger of two large inlets (the other being Gulf St Vincent) on the southern coast of Australia, in the state of South Australia, facing the Great Australian Bight. It spans from the Cape Catastrophe and ...
with narrower phyllodes and fewer inflorescences. However, no subspecies are currently recognised, though an informal classification distinguishes wetland and dryland forms, the latter with narrower phyllodes.
In 1921 Joseph Maiden
Joseph Henry Maiden (25 April 1859 – 16 November 1925) was a botanist who made a major contribution to knowledge of the Australian flora, especially the genus ''Eucalyptus''. This botanist is denoted by the author abbreviation when citing ...
described ''Acacia westonii'' from the northern and western slopes of Mount Jerrabomberra near Queanbeyan
Queanbeyan ( ) is a city in the south-eastern region of New South Wales, Australia, located adjacent to the Australian Capital Territory in the Southern Tablelands region. Located on the Queanbeyan River, the city is the council seat of the ...
in New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
. He felt it was similar to, but distinct from, ''A. pycnantha'' and was uncertain whether it warranted species rank. His colleague Richard Hind Cambage
Richard Hind Cambage (7 November 1859 – 28 November 1928) was an Australian surveyor and botanist who made important contributions to the description of the genera ''Acacia'' and ''Eucalyptus''.
Early life
Cambage, son of John Fisher Camba ...
grew seedlings and reported they had much longer internodes
A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, stores nutrien ...
than those of ''A. pycnantha'', and that the phyllodes appeared to have three nectaries
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualist ...
rather than the single one of the latter species. It is now regarded as a synonym of ''A. pycnantha''.[
Common names recorded include golden wattle, green wattle, black wattle, and broad-leaved wattle.][ At ]Ebenezer Mission
Ebenezer Mission, also known as Wimmera mission, Hindmarsh mission and Dimboola mission, was a mission station for Aboriginal people established near Lake Hindmarsh in Victoria, Australia (near Jeparit) in 1859 by the Moravian Church on the lan ...
in the Wergaia
The Wergaia or Werrigia people are an Aboriginal Australian group in the Mallee and Wimmera regions of north-Western Victoria, made up of a number of clans. The people were also known as the Maligundidj (in the Wotjobaluk language) which mea ...
country of north-western Victoria the Aboriginal people referred to it as ''witch''.
Hybrids of the species are known in nature and cultivation. In the Whipstick forest near Bendigo
Bendigo ( ) is a city in Victoria, Australia, located in the Bendigo Valley near the geographical centre of the state and approximately north-west of Melbourne, the state capital.
As of 2019, Bendigo had an urban population of 100,991, makin ...
in Victoria, putative hybrids with Whirrakee wattle ('' Acacia williamsonii'') have been identified; these resemble hakea wattle (''Acacia hakeoides
''Acacia hakeoides'', known colloquially as hakea wattle, hakea-leaved wattle, or western black wattle is a species of ''Acacia'' native to southern Australia. It can be found growing in sandy soils in semiarid
A semi-arid climate, semi-desert ...
''). Garden hybrids with Queensland silver wattle (''Acacia podalyriifolia
''Acacia podalyriifolia'' is a perennial tree which is fast-growing and widely cultivated. It is native to Australia but is also naturalised in Malaysia, Africa, India and South America. Its uses include environmental management and it is al ...
'') raised in Europe have been given the names ''Acacia x siebertiana'' and ''Acacia x deneufvillei''.[
]
Distribution and habitat
Golden wattle occurs in south-eastern Australia from South Australia
South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
's southern Eyre Peninsula
The Eyre Peninsula is a triangular peninsula in South Australia. It is bounded by the Spencer Gulf on the east, the Great Australian Bight on the west, and the Gawler Ranges to the north.
Originally called Eyre’s Peninsula, it was named aft ...
and Flinders Ranges
The Flinders Ranges are the largest mountain range in South Australia, which starts about north of Adelaide. The ranges stretch for over from Port Pirie to Lake Callabonna.
The Adnyamathanha people are the Aboriginal group who have inhabi ...
across Victoria and northwards into inland areas of southern New South Wales and the Australian Capital Territory
The Australian Capital Territory (commonly abbreviated as ACT), known as the Federal Capital Territory (FCT) until 1938, is a landlocked federal territory of Australia containing the national capital Canberra and some surrounding townships. ...
. It is found in the understorey
In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abov ...
of open eucalypt
Eucalypt is a descriptive name for woody plants with capsule fruiting bodies belonging to seven closely related genera (of the tribe Eucalypteae) found across Australasia:
''Eucalyptus'', '' Corymbia'', '' Angophora'', ''Stockwellia'', ''Allosyn ...
forests on dry, shallow soils.[
The species has become ]naturalised
Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the i ...
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 weed
A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place", or a plant growing where it is not wanted.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. ...
y in bushland near Hobart
Hobart ( ; Nuennonne/Palawa kani: ''nipaluna'') is the capital and most populous city of the Australian island state of Tasmania. Home to almost half of all Tasmanians, it is the least-populated Australian state capital city, and second-small ...
. In Western Australia, it is found in the Darling Range
The Darling Scarp, also referred to as the Darling Range or Darling Ranges, is a low escarpment running north–south to the east of the Swan Coastal Plain and Perth, Western Australia. The escarpment extends generally north of Bindoon, to th ...
and western wheatbelt as well as Esperance and Kalgoorlie
Kalgoorlie is a city in the Goldfields–Esperance region of Western Australia, located east-northeast of Perth at the end of the Great Eastern Highway. It is sometimes referred to as Kalgoorlie–Boulder, as the surrounding urban area includ ...
.
Outside Australia it has become naturalised in South Africa, Tanzania, Italy, Portugal, Sardinia, India, Indonesia and New Zealand.[ It is present in California as a garden escapee, but is not considered to be naturalised there.] In South Africa, where it had been introduced between 1858 and 1865 for dune stabilization and tannin
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.
The term ''tannin'' (from Anglo-Norman ''tanner'', ...
production, it had spread along waterways into forest, mountain and lowland fynbos
Fynbos (; meaning fine plants) is a small belt of natural shrubland or heathland vegetation located in the Western Cape and Eastern Cape provinces of South Africa. This area is predominantly coastal and mountainous, with a Mediterranean clim ...
, and borderline areas between fynbos and karoo
The Karoo ( ; from the Afrikaans borrowing of the South Khoekhoe !Orakobab or Khoemana word ''ǃ’Aukarob'' "Hardveld") is a semi-desert natural region of South Africa. No exact definition of what constitutes the Karoo is available, so its ext ...
. The gall-forming wasp ''Trichilogaster signiventris
''Trichilogaster signiventris'', commonly known as the golden wattle bud-galling wasp, is a species of Australian chalcid wasps that parasitises, among others, ''Acacia pycnantha'' (golden wattle). It has been introduced into South Africa, wher ...
'' has been introduced in South Africa for biological control
Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...
and has reduced the capacity of trees to reproduce throughout their range. The eggs are laid by adult wasps into buds of flower heads in the summer, before hatching in May and June when the larvae induce the formation of the grape-like galls and prevent flower development. The galls can be so heavy that branches break under their weight. In addition, the introduction in 2001 of the acacia seed weevil '' Melanterius compactus'' has also proved effective.
Ecology
Though plants are usually killed by a severe fire, mature specimens are able to resprout. Seeds are able to persist in the soil for more than five years, germinating after fire.[
Like other wattles, ''Acacia pycnantha'' fixes nitrogen from the atmosphere. It hosts bacteria known as ]rhizobia
Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes (Fabaceae). To express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. In gene ...
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
''Bradyrhizobium japonicum'' is a species of legume- root nodulating, microsymbiotic nitrogen-fixing bacteria. The species is one of many Gram-negative, rod-shaped bacteria commonly referred to as rhizobia. Within that broad classification, wh ...
'' and genus ''Burkholderia
''Burkholderia'' is a genus of Pseudomonadota whose pathogenic members include the ''Burkholderia cepacia'' complex, which attacks humans and ''Burkholderia mallei'', responsible for glanders, a disease that occurs mostly in horses and related a ...
'' in both countries. It is unclear whether the golden wattle was accompanied by the bacteria to the African continent or encountered new populations there.
Self-incompatible
Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals ...
, ''Acacia pycnantha'' cannot fertilise itself and requires cross-pollination
Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds, most often by an animal or by wind. Pollinating agents can be animals such as insects, birds ...
between plants to set seed. Birds facilitate this and field experiments keeping birds away from flowers greatly reduces seed production. Nectaries are located on phyllodes; those near open flowers become active, producing nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...
that birds feed upon just before or during flowering. While feeding, birds brush against the flower heads and dislodge pollen and often visit multiple trees. Several species of honeyeater
The honeyeaters are a large and diverse family (biology), family, Meliphagidae, of small to medium-sized birds. The family includes the Epthianura, Australian chats, myzomelas, friarbirds, wattlebirds, Manorina, miners and melidectes. They are ...
, including the white-naped, yellow-faced, New Holland, and occasionally white-plumed and crescent honeyeater
The crescent honeyeater (''Phylidonyris pyrrhopterus'') is a passerine bird of the honeyeater family Meliphagidae native to southeastern Fauna of Australia, Australia. A member of the genus ''Phylidonyris'', it is most closely related to the comm ...
s, and Eastern spinebill
The eastern spinebill (''Acanthorhynchus tenuirostris'') is a species of honeyeater found in south-eastern Australia in forest and woodland areas, as well as gardens in urban areas of Canberra, Sydney, Melbourne and Adelaide. It is around 15&nb ...
s have been observed foraging. Other bird species include the silvereye
The silvereye or wax-eye (''Zosterops lateralis'') is a very small omnivorous passerine bird of the south-west Pacific. In Australia and New Zealand its common name is sometimes white-eye, but this name is more commonly used to refer to all membe ...
, striated, buff-rumped and brown thornbills. As well as eating nectar, birds often pick off insects on the foliage. Honeybees, native bees, ants and flies also visit nectaries, but generally do not come into contact with the flowers during this activity. The presence of ''Acacia pycnantha'' is positively correlated with numbers of swift parrot
The swift parrot (''Lathamus discolor'') is a species of broad-tailed parrot, found only in southeastern Australia. The species breeds in Tasmania during the summer and migrates north to south eastern mainland Australia from Griffith- Warialda ...
s overwintering in box–ironbark forest
Box–ironbark forest is a forest or woodland ecosystem that is largely limited to central Victoria in south-eastern Australia. Because its component tree species produce abundant nectar and pollen throughout the year, it is important for the c ...
in central Victoria, though it is not clear whether the parrots are feeding on them or some other factor is at play.
The wood serves as food for larvae of the jewel beetle
Buprestidae is a family of beetles known as jewel beetles or metallic wood-boring beetles because of their glossy iridescent colors. Larvae of this family are known as flatheaded borers. The family is among the largest of the beetles, with some ...
species ''Agrilus assimilis
''Agrilus'' is a genus of Buprestidae, jewel beetles, notable for having the largest number of species (about 3000) of any single genus in the animal kingdom.
file:Agrilus aureus dorsal1.jpg, ''Agrilus aureus''
...
'', '' A. australasiae'' and '' A. hypoleucus''. The larvae of a number of butterfly species feed on the foliage including the fiery jewel, icilius blue, lithocroa blue and wattle blue. ''Trichilogaster
''Trichilogaster'' is a small genus of chalcid wasps in the Family (biology), family Melanosomellidae, previously they were included in Family (biology), family Pteromalidae Family (biology), subfamily Ormocerinae. With one described exception, ...
'' wasps form galls in the flowerheads, disrupting seed set and
'' Acizzia acaciaepycnanthae'', a psyllid
Psyllidae, the jumping plant lice or psyllids, are a family of small plant-feeding insects that tend to be very host-specific, i.e. each plant-louse species only feeds on one plant species (monophagous) or feeds on a few closely related plants ...
, sucks sap from the leaves.
''Acacia pycnantha'' is a host to rust fungus species in the genus '' Uromycladium'' that affect the phyllodes and branches. These include '' Uromycladium simplex'' that forms pustules and '' U. tepperianum'' that causes large swollen brown to black galls that eventually lead to the death of the host plant. Two fungal species have been isolated from leaf spot
A leaf spot is a limited, discoloured, diseased area of a leaf that is caused by fungal, bacterial or viral plant diseases, or by injuries from nematodes, insects, environmental factors, toxicity or herbicides. These discoloured spots or lesions ...
s on ''Acacia pycnantha'': '' Seimatosporium arbuti'', which is found on a wide range of plant hosts, and ''Monochaetia lutea
''Monochaetia'' is a genus of fungi in the family Sporocadaceae. Species in the genus are typically plant parasitism, parasites and saprobes, and cause leaf spot diseases on various host (biology), hosts.
The genus ''Monochaetia'' was introduced ...
''.
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 wattles.[ Trees can be harvested for tannin from seven to ten years of age.] Commercial use of its timber is limited by the small size of trees, but it has high value as a fuel wood. The scented flowers have been used for perfume
Perfume (, ; french: parfum) is a mixture of fragrant essential oils or aroma compounds (fragrances), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agreeable scent. Th ...
making,[ and honey production in humid areas. However, the pollen is too dry to be collected by bees in dry climates.] In southern Europe, it is one of several species grown for the cut-flower trade and sold as "mimosa". Like many other species of wattle, ''Acacia pycnantha'' exudes gum when stressed.[ Eaten by ]indigenous Australian
Indigenous Australians or Australian First Nations are people with familial heritage from, and membership in, the ethnic groups that lived in Australia before British colonisation. They consist of two distinct groups: the Aboriginal peoples ...
s, the gum has been investigated as a possible alternative to gum arabic
Gum arabic, also known as gum sudani, acacia gum, Arabic gum, gum acacia, acacia, Senegal gum, Indian gum, and by other names, is a natural gum originally consisting of the hardened sap of two species of the '' Acacia'' tree, ''Senegalia sen ...
, commonly used in the food industry.
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. 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
''Eucalyptus cladocalyx'', commonly known as sugar gum, is a species of eucalypt tree found in the Australian state of South Australia. It is found naturally in three distinct populations - in the Flinders Ranges, Eyre Peninsula and on Kangar ...
'') to make a two-layered windbreak. One form widely cultivated was originally collected on Mount Arapiles
Mount Arapiles is a rock formation that rises about above the Wimmera plains in western Victoria, Australia. It is located in Arapiles approximately west of the town of Natimuk and is part of the Mount Arapiles-Tooan State Park. Arapile ...
in western Victoria. It is