acacia_longifolia ficha

Acacia longifolia

Evergreen shrub or small tree, with bright yellow spikes; very frequent in coastal dunes.

Scientific name: Acacia longifolia (Andrews) Willd.

Common names: Sydney golden wattle, golden wattle

Family: Fabaceae (Leguminosae)

Status in Portugal: invasive species (listed in the annex I of Decreto-Lei n° 565/99, of 21 December)

Risk Assessment score: (in development)

Synonymy: Acacia longifolia (Andrews) Willd. var. typica Benth., Mimosa longifolia Andrews, Mimosa macrostachya Poiret, Phyllodoce longifolia (Andrews) Link Racosperma longifolium (Andrews) Martius

Last update: 30/06/2014

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How to recognise it

Shrub or small tree up to 8 m.

Leaves: evergreen, reduced to laminar phyllodes, oblonglanceolate; with 2-4 longitudinal veins.

Flowers: bright yellow arranged in axillary spikes.

Fruits: cylindrical pods, contorted in maturation; seeds with a short, whitish funicle.

Flowering: December to April.  

Similar species

Acacia cyclops (coastal wattle) is similar but has phyllodes that are generally smaller, lighter and slightly falcate; the flowers are arranged in globular flower heads, the pod is compressed and the funicle is scarlet and completely encircles the seed. Acacia melanoxylon (Australian blackwood) also has some similarity, but the phyllodes are falcate, the flowers are arranged in globular flower heads and the seeds are completely encircled by an orange funicle.

 

Plant habit
Tree habit
Plant habit before flowering
Habit of an isolated tree in a garden
Tree habit
Close-up of phyllodes with several longitudinal veins
Yellow flowers arranged in globular flower heads
Bright (green-yellow) immature pods, between the phyllodes
Grey-green bipinnate leaves
Bipinnate leaves showing the central rachis with small glands at the junction of pinnae
Bright yellow flowers arranged in globular flower heads
Brownish-red pods ± constricted between the seeds
Plant habit
Bipinnate leaves with thorny stipules
Close-up of thorny stipules
Bright yellow globular flower heads, showing different stages of development
Curved sickle-shaped immature pods
Phyllodes showing several longitudinal veins
Close-up of flower buds, spike-shaped
Shoots with bright yellow flowers arranged in spikes
Close-up of immature pods, in the beginning of development
Pods contorted in maturation
Mature pods showing the seeds with a short, whitish funicle
Branch with dark green bipinnate leaves and golden apexes on young shoots
Bipinnate leaves showing the glands irregularly distributed along the central rachis
Close-up of golden young foliage-tip
Pale yellow flowers arranged in globular flower heads
Branches with immature pods
Dark brown pods, constricted between the seeds
Basal rosette with leaves of large dimensions
Habit of an isolated tree
Habit of mature tree in flower
Habit of mature tree
Falcate phyllodes, with one longitudinal vein and base asymmetric
Young branch showing bipinnate leaves and falcate phyllodes with several longitudinal veins
Pale yellow flowers arranged in globular flower heads
Close-up of immature pods, contorted
Golden-yellow flowers arranged in globular flower heads
Similar species: Acacia saligna is similar, but their phyllodes are greenish-blue in colour and symmetric on the base
Pale yellow flowers arranged in globular flower heads
Compressed light brown pods, almost linear
Habit of mature tree in flower
Glaucous-green phyllodes, symmetrical, with one longitudinal vein
Golden-yellow flowers arranged in globular flower heads
Immature pods, constricted between the seeds
Habit of a young tree
Young foliage with reddish terminal leaflets
Close-up of leaflets with 2-4 irregular lobes at their bases
Close-up of greenish flowers
Immature reddish-coloured fruits
Plant habit
Bipinnate leaves
Close-up of young flower spike
Flower spike
Dark brown pods, compressed and straight
Close-up of mature pods, contorted
Linear-lanceolate leaves
Plant habit
Plant habit
Plant habit
Plant habit
Tiny capitula distributed along the lateral branches
Plant habit
Close-up of seeds completely encircled by an orange funicle
Flowers arranged in oblong panicles, dense ± constricted
Plant habit
Plant habit
Plant habit in flower
Close-up of leaves showing one with 3 lobes and many linear to lanceolate, entire
Plant habit
Young leaves, ovate to lanceolate, bluish-green
Adult leaves, alternate, lanceolate to falcate
Flowers with long stamens, very numerous, yellowish-white
Botões florais
Plant habit showing leaves with reddish apexes
Lanceolate leaves along reddish twigs
Plant habit
Close-up of needle-like leaves
Bland flowers, arranged in small axillary clusters
Woody follicle
Burned plant with many fruits (follicles)
Plant habit
Ovate-lanceolate leaves with undulated margins
Close-up of flowers with yellow stamens
Plant habit
Odd-pinnate leaves and immature pods
Close-up of branches with spiny stipules
Flashy white flowers
Flattened pods, slightly constricted between the seeds
Plant habit
Close-up of pinnatisect leaves, tomentose-white on the lower surface and green on the upper surface
Close-up of a capitulum with yellow marginal flowers with a blackened-green centre
Capitulum with involucral bracts, usually scarious on margins and with a terminal appendage with deep indentations
Capitulum in frutification with densely woolly cypselas
Linear-lanceolate leaves, long-attenuate to a fine point
Close-up of leaf base with sheath enwrapping the culm and yellow-green auricles
Close-up of underground rhizomes
Capitula with greenish-white marginal flowers and greenish-yellow disk flowers
Close-up of three-lobed leaves
Close-up of a young basal rosette after cutting
Close-up of leaves with razor sharp margins
Panicles
Plant habit
Close-up of a flower
Close-up of a purple flower
Spiny capsule, when immature
Spiny capsule, when mature
Close-up of a mature capsule showing black seeds inside
Numerous capitula with ligulate flowers, white and pink
Capitulum with white marginal flowers and yellow disk flowers
Plant habit
Close-up of a leaf with marginal spine
Close-up of young inflorescence
Plant habit
Close-up of ovate leaves with a slightly serrate margin
Capitula showing 5 ligulate flowers, white and yellow disk flowers
Close-up of a pappus of short hairs whose disposition is similar to a star
Plant habit
Plant habit
Trifoliate leaves with obcordate leaflets
Close-up of flowers with yellow petals
Plant habit
Close-up of linear leaves showing small cilia in the upper part of the sheath
Spiciform racemes, digitate, 1 ± sessile (on right) and the other pedunculate (on left)
Plant habit
Close-up of ovate-lanceolate leaves
Immature fruits showing several segments
Close-up of flowers raceme
Black berries
Plant habit
Close-up of white-tomentose leaves
Close-up of acute to ovate leaves
Close-up of flowers showing 6 stamens with yellow anthers
Plant habit
Leaves with a spiny margin and an apical spine, blackened, arranged in a large basal rosette
Close-up of greenish-yellow flowers (small portion of a panicle)
Close-up of fleshy leaves
Close-up of leaves with equilateral in cross-section
Close-up of a pink flower showing numerous yellow stamens
Close-up of yellow flower showing numerous petals and stamens
Plant habit
Close-up of an oblong cladode
Close-up of an orange flower with pale yellow stamens
Close-up of oblong-obovate fruits, edible
Close-up of calyces
Close-up of funnel-shaped flowers, large, blue, becoming pink when they wither
Deltoid and lustrous leaves, with 3-5 lobes on each surface, giving them an angular look
Close-up of tubular flowers arranged in capitula
Close-up of green leaves (Photo: Francisco Carrapiço)
Close-up of reddish leaves (Photo: Lísia Lopes)
Aerial leaves showing swollen petioles in the inner part
Blue/lilac flowers arranged in a spike (Photo: Lísia Lopes)
Invaded area (Photo: Lísia Lopes)
Leaves finely divided into numerous segments and arranged in whorls of 4-6 per node
Flowers from side-on
Close-up of leaves of Egeria densa, very similar to Elodea canadensis, but with more than 3 leaves in each node
Close-up of male flowers of Egeria densa, similar to Elodea canadensis, but with longer petals (7 – 12 mm)
Inflorescences with overlapping spikelets
Close-up of an inflorescence showing the anthers
Close-up of a leaf deeply dissected (into 8-30 segments)
Invaded area
Shoot from side-on
Close-up of open flowers and flowers without petals
Close-up of flowers (Photo: Lísia Lopes)
Micrsocopic view of capsules (Photo: Sílvia Castro)
Closed capsules
Brown cypselas with a hairy pappus
Albizia julibrissin is similar, but the pods have a more irregular shape and has larger leaves (with more pinnae and leaflets)
Invaded area
Invaded area
Invaded area
Very bland flowers, arranged in axillary fascicles
Plant habit (Photo: Cristina Medeiros)
Young plant showing purple stems (Photo: Cristina Medeiros)
Triangular to rhomboid leaves with serrate margins (Photo: António Pestana)
Flowers in dense capitula (Photo: António Pestana)
Plant habit (Photo: Direção Regional dos Recursos Florestais)
Yellow flowers, arranged in erect inflorescences (Photo: Ruben Heleno)
Close-up of stamens (Photo: Direção Regional dos Recursos Florestais)
Close-up of open capsules with orange-red insides (Photo: Ruben Heleno)
Close-up of rhizomes (Photo: Direção Regional dos Recursos Florestais)
Plant habit
Close-up of the stem and leaves covered by hairs
Close-up of a capitulum
Close-up of prickles on petioles and veins of leaves
Close-up of reddish drupes (Photo: Direção Regional dos Recursos Florestais)
Close-up of capitula
Mature, open pods showing some seeds
Close-up of the rhytidome showing longitudinal ridges
Invaded area (Photo: Direção Regional dos Recursos Florestais)
Close-up of a capitulum in frutification (cypselas)
Invaded area in a dune ecosystem where A. longifolia is almost in the primary dune
Similar species: Acacia cyclops is similar but the pods are wider and the seeds are completely surrounded by a scarlet funicle
Similar species: the phyllodes of Acacia melanoxylon are similar but they are falcate
Similar species: Acacia cyclops is similar but the pods are wider and the seeds are completely surrounded by a scarlet funicle
Invaded area showing large amount of litter and the absence of other species
Open, mature pods, showing the seeds completely surrounded by a scarlet funicle
Similar species: Acacia dealbata is very similar, but has greenish-grey leaves and the rachis presents glands at the junction of each pinnae pair
Mature twisted pods with no seeds
Invaded area showing absence of other species
Invaded riparian area
Immature pods
Close-up of pods
Mature pods, showing seeds with a short funicle.
Invaded area along a roadside
Invaded area (Photo: Ruben Heleno)
Close-up of a seed showing the short, whitish funicle
Invaded dune area
Invaded area along a roadside
Mountainous area invaded by Acacia melanoxylon
Close-up of phyllodes in the sprouts that form on the stumps of cut trees are wider when compared to the other phyllodes
Invaded area
Close-up of immature seeds completely encircled by a funicle
Invaded area
Close-up of triangular, oblong capsules (fruits)
Close-up of the disk of the capitulum after the fruit has fallen
Close-up of a capitulum showing the involucral bracts in several series
Invaded area in a coastal clift
Invadida area (Photo: Manuel José Jesus)
Azolla filiculoides (reddish) close to other aquatic plants (Photo: Lísia Lopes)
Invaded area by Azolla filiculoides (reddish area) (Photo: Lísia Lopes)
Invaded area
Inflorescences
Close-up of ovoid-globular capitula, reddish-purple
Capitula showing yellow flowers (center) and involucral bracts (left)
Capitula with yellow tubular flowers (Photo: Lísia Lopes)
Close-up of a flower-bud
Ovoid, fleshy fruit
Invaded area
Invaded area close to the ocean
Invaded area
Invaded area along a roadside where, after cutting, the species spreads in the road tar
Basal rosette of leaves, in a dune system
Invaded area in a dune system
Invaded area (Photo: Lísia Lopes)
Invaded area along the margins of a watercourse
Close-up of flower heads (on right) and cypselas (on left)
Cypselas (fruits), some with a brown pappus of long hairs
Woody follicle when immature
Woody follicles when mature
Invaded area
Invaded area
Seedlings showing the 2 rounded cotyledons
Invaded area (rupicolous species)
Similar species: the phyllodes of Acacia longifolia are similar but they have many veins; the fruit is a pod
Invaded area on the coast
Invaded area in a dune system
Invaded area in a slope showing flowers of 2 colors
Invaded area
Invaded area (dense mat on the water surface) (Photo: Lísia Lopes)
Invaded area (dense mats on the water surface)
Invaded area (Photo: Sílvia Castro)
Yellow flowers, arranged in capitula, which in turn are arranged in a panicle
Rhytidome of a mature tree
Close-up of a young sprout, with no leaves, showing a leaf scar
Invaded area
Close-up of still-closed capitula
Mature fruits, open, showing the seeds wrapped by mucilage
Close-up of spikelets showing the stamens (darker) and the stigmas (plumose)
Close-up of young capitula
Invaded area by Egeria densa, very similar to E. canadensis, but with flowers that grow up to 3 cm above the surface of the water
Invaded area
Invaded area
Invaded area
Similar species: the flower of Petunia integrifolia has some similarity but the leaves are smaller
Invaded area in winter, when trees lose their leaves
Close-up of yellow flowers arranged in capitula
Habit of an isolated tree

Characteristics that aid invasion

It reproduces by seed, producing many seeds that remain viable in the ground for many years. Seed production may reach 12000 seeds/m2/year, where most part accumulates underneath the tree. The seeds are dispersed by animals, mainly birds and ants, which lead to the formation of invasion foci. Germination is stimulated by fire. It presents a high growth rate.

The species also propagates vegetatively, forming shoots from the stump in some situations. However, in understory areas, under some climate conditions or seasons of the year, the species sprouts much less vigorously or may even not sprout.

 

Native distribution area
Southeast Australia.

Distribution in Portugal

Mainland Portugal (Trás-os-Montes, Minho, Douro Litoral, Beira Litoral, Estremadura, Ribatejo, Alto Alentejo, Baixo Alentejo, Algarve), Madeira archipelago (islands of Madeira and Porto Santo).

A.longifolia

Geographic areas where there are records of Acacia longifolia

Other places where the species is invasive

Europe (France, Spain, Italy), South Africa, New Zealand, South America (Brazil), Western USA (California), Asia (Israel).

 

Introduction reasons

For ornamental purposes and for erosion control, mainly in costal dunes.

 

Preferential invasion environments

Coastal dunes and watercourses. It also appears, although less frequently, along roadsides and over interior mountainous areas.

It is one of the invasive species that causes stronger impacts on dune ecosystems.

Impacts on ecossystems

It forms very dense populations inhibiting the development of native vegetation, diminishing the flow of watercourses.

It produces a lot of nitrogen-rich litter, which promotes change in soil composition (carbon and nutrients, mainly nitrogen) and microbiology.

 

Economic impacts

Expensive control methods.  

 

Natura 2000 Network habitats more subject to impacts

– Southern riparian galleries and thickets (Nerio-Tamaricetea and Securinegion tinctoriae)  (92D0 pt1, pt2);

– Vegetated sea cliffs of the Atlantic and Baltic coasts (1230);

– Shifting dunes along the shoreline with Ammophila arenaria («white dunes») (2120);

– Fixed coastal dunes with herbaceous vegetation («grey dunes») (2130);

– Atlantic decalcified fixed dunes (Calluno-Ulicetea) (2150);

Dunes with Salix repens ssp. argentea (Salicion arenariae) (2170);

– Wooded dunes of the Atlantic, Continental and Boreal region (2180);

– Humid dune slacks (2190); – Malcolmietalia dune grasslands (2230);

– Coastal dunes with Juniperus spp. (2250);

Cisto-Lavenduletalia dune sclerophyllous scrubs (2260);

– Wooded dunes with Pinus pinea and/or Pinus pinaster (2270);

– Inland dunes with open Corynephourus and Agrostis grasslands (2330);

– Rivers with muddy banks with Chenopodium rubri p. p. and Bidention p. p. vegetation (3270).

Controlling an invasive species demands a well-planned management, which includes the determination of the invaded area, identifying the causes of invasion, assessing the impacts, defining the intervention priorities, selecting the adequate control methodologies and their application. Afterwards it is fundamental to monitor the efficiency of the methodologies and recuperation of the intervened area as to perform, whenever necessary, the follow-up control.

The control methodologies used for Acacia longifolia include:

Physical control

Hand pulling: preferential methodology for seedlings and small plants. When in more compacted substrates, hand pulling must be made during the rainy season as to facilitate the removal of the root system. It should be guaranteed that no stumps and main roots are left in the ground.

Cutting: preferential methodology for adult plants. Care should be taken to cut the trunk as close to the ground as possible by using manual and/or mechanical equipment. It should be done before seed maturation. Most times, this operation is enough for the effective control of the species. However, there are situations where the sprouting occurs after cutting, making necessary the application of this methodology in posterior interventions in combination with other methodologies, namely the application of herbicide.

 

Physical + chemical control

Cut stump method: Apply to adult plants. Cut the trunk as close to the ground as possible and immediately (in the following seconds) apply herbicide (active substance: glyphosate) to the cut stump. If shoots should latter on appear, these should be immediately eliminated when they reach 25 to 50 cm height by cutting or pulling.

 

Biological control

The wasp Trichilogaster acaciaelongifoliae (Hymenoptera: Pteromalidae) is used with success in South Africa since 1982. This species forms galls on the floral and vegetative buds of A. longifolia inhibiting the formation of up to 90% of the seeds. Its use is combined with the weevil [Melanterius ventralis (Coleoptera: Curculionidae)] that feeds off the few remaining seeds that are formed.

OThe specificity tests, in quarantine, to evaluate the security in using T. acaciaelongifoliae in Portugal were officially authorized and concluded in 2010. Final authorization for liberation in the natural medium is being awaited.

 

Prescribed fire

It may be strategically used to favour germination of the seed bank, e.g., after the control of adult individuals (with the adequate management of the resulting biomass) and the subsequent elimination of seedlings. This method provides an advantageous reduction of the seed bank, both by destroying part of the seeds or by stimulating the germination of the remainders.

Visit the webpage How to Control for additional and more detailed information about the correct application of these methodologies.

Agricultural Research Council – Plant Protection Research Institute – Weed Research Division (2014) Management of invasive alien plants: A list of biocontrol agents released against invasive alien plants in South Africa. Available: http://www.arc.agric.za/arc-ppri/Documents/WebAgentsreleased.pdf [Retrieved 03/03/2014].

CABI (2012) Acacia longifolia. In: Invasive Species Compendium. CAB International, Wallingford, UK. Available: http://www.cabi.org/isc/ [Retrieved 06/11/2012].

Dennill GB, Donnelly D, Stewart K, Impson FAC (1999) Insect agents used for the biological control of Australian Acacia species and Paraserianthes lophanta (Willd.) Nielsen (Fabaceae) in South Africa. African Entomology: Memoir no.1: 45-54.

Marchante E, Freitas H, Marchante H (2008) Guia prático para a identificação de plantas invasoras de Portugal Continental. Imprensa da Universidade de Coimbra, 183pp.

Marchante E, Kjøller A, Struwe S, Freitas H (2008) Short- and long-term impacts of Acacia longifolia invasions on the belowground processes of a Mediterranean coastal dune ecosystem. Applied Soil Ecology 40: 210-217.

Marchante H, Freitas H, Hoffman JH (2010) Seed ecology of an invasive alien species, Acacia longifolia (Fabaceae), in Portuguese dune ecosystems. American Journal of Botany 97 (11): 1780-1790.

Marchante H, Freitas H, Hoffman JH (2011) The potential role of seed banks in the recovery of dune ecosystems after removal of invasive plant species. Appl Veg Sci 14: 107-119.

 

This post is also available in: Portuguese (Portugal)