acacia

 

(əkā'shə) , any plant of the large leguminous genus Acacia, often thorny shrubs and trees of the family Leguminosae (pulse family). Chiefly of the tropics and subtropics, they are cultivated for decorative and economic purposes. Acacias are characteristic of savanna vegetation and are especially numerous in the South African bushveld. The foliage often appears feathery because of the many small leaflets, but in some species leaflike flattened stems contain chlorophyll and take the place of leaves. Various Old World species (especially A. arabica and A. senegal) yield gum arabic; other species, chiefly A. catechu, yield the dye catechu. Blackwood (A. melanoxylon) is valued in Australia for its hardwood timber. Other members of the genus are valuable for lac, for perfume and essential oils, and for tannins; some are used as ornamentals. The Australian acacias are commonly called wattles—their pliable branches were woven into the structure of the early wattle houses and fences—and Wattle Day celebrates the national flower at blossoming time. Many wattles are cultivated elsewhere, particularly in California, as ornamentals for their characteristic spherical, dense flowers. The Central American bullhorn acacias (e.g., A. sphaerocephala) have large hollow thorns inhabited by ants that are said to feed upon a sweet secretion of the plant and in turn guard it against leaf-eating insects. The most common acacia indigenous to the United States is the cat's-claw (A. gregii) of the arid Southwest. The biblical shittim wood is thought to have come from an acacia. Various species of locust are sometimes called acacia, and acacias may be called mimosa; all are of the same family. Acacia is classified in the division Magnoliophyta, class Magnoliopsida, order Rosales, family Leguminosae.

Acacia
Acacia greggii
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Fabales Family: Fabaceae Subfamily: Mimosoideae Tribe: Acacieae Genus: Acacia Miller
Species
About 1,300; see List of Acacia species

Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Linnaeus in 1773.

Acacias are also known as thorntrees or wattles, including the yellow-fever acacia and umbrella acacias.

There are roughly 1300 species of Acacia worldwide, about 960 of them native to Australia, with the remainder spread around the tropical to warm-temperate regions of both hemispheres, including Africa, southern Asia, and the Americas.

Classification

The genus Acacia is apparently not monophyletic. This discovery has led to the breaking up of Acacia into five new genera as discussed in list of Acacia species. In common parlance the term "acacia" is occasionally misapplied to species of the genus Robinia, which also belongs in the pea family. Robinia pseudoacacia, an American species locally known as Black locust, is sometimes called "false acacia" in cultivation in the United Kingdom.

Geography

The southernmost species in the genus are Acacia dealbata (Silver Wattle), Acacia longifolia (Coast Wattle or Sydney Golden pattle), Acacia mearnsii (Black Wattle), and Acacia melanoxylon (Blackwood), reaching 43°30' S in Tasmania, Australia, while Acacia caven (Espinillo Negro) reaches nearly as far south in northeastern Chubut Province of Argentina. Australian species are usually called wattles, while African and American species tend to be known as acacias.

Acacia albida, Acacia tortilis and Acacia iraqensis can be found growing wild in the Sinai desert and the Jordan valley. It is found in the savanna vegetation of the tropical continental climate.

Description

The leaves of acacias are compound pinnate in general. In some species, however, more especially in the Australian and Pacific islands species, the leaflets are suppressed, and the leaf-stalks (petioles) become vertically flattened, and serve the purpose of leaves. These are known as phyllodes. The vertical orientation of the phyllodes protects them from intense sunlight, as with their edges towards the sky and earth they do not intercept light so fully as horizontally placed leaves. A few species (such as Acacia glaucoptera) lack leaves or phyllodes altogether, but possess instead cladodes, modified leaf-like photosynthetic stems functioning as leaves.

The small flowers have five very small petals, almost hidden by the long stamens, and are arranged in dense globular or cylindrical clusters; they are yellow or cream-colored in most species, whitish in some, even purple (Acacia purpureapetala) or red (Acacia leprosa Scarlet Blaze).

The plants often bear spines, especially those species growing in arid regions. These sometimes represent branches which have become short, hard and pungent, or sometimes leaf-stipules. Acacia armata is the Kangaroo-thorn of Australia and Acacia erioloba is the Camelthorn of Africa.

Symbiosis

In the Central American Acacia sphaerocephala, Acacia cornigera, and Acacia collinsii (collectively known as the bullthorn acacias), the large thorn-like stipules are hollow and afford shelter for ants, which feed on a secretion of sap on the leaf-stalk and small, lipid-rich food-bodies at the tips of the leaflets called Beltian bodies; in return they usually protect the plant against herbivores. Some species of ants will also fight off competing plants around the acacia, while other ant species will do nothing to benefit their host.

Pests

In Australia, Acacia species are sometimes used as food plants by the larvae of hepialid moths of the genus Aenetus including A. ligniveren. These burrow horizontally into the trunk then vertically down. Other Lepidoptera larvae which have been recorded feeding on Acacia include Brown-tail, Endoclita malabaricus and Turnip Moth. The leaf-mining larvae of some bucculatricid moths also feed on Acacia: Bucculatrix agilis feeds exclusively on Acacia horrida and Bucculatrix flexuosa feeds exclusively on Acacia nilotica.

Acacias contain a number of organic compounds that defend them from pests and grazing animals.^[1]

Uses

Food uses

Acacia seeds are often used for food and a variety of other products.

In Burma, Laos and Thailand, the feathery shoots of Acacia pennata (common name cha-om, ชะอม and su pout ywet in Burmese) are used in soups, curries, omelettes, and stir-fries.

Honey made by bees using the acacia flower as forage is considered a delicacy, appreciated for its mild flowery taste, soft running texture and glass like appearance.

It is listed as an ingredient in soft drinks Fresca and Barq's Root Beer. Läkerol [1], the refreshment pastille originated in Sweden list as an ingredient. As do Altoids peppermints.

Gum

Various species of acacia yield gum. True gum arabic is the product of Acacia senegal, abundant in dry tropical West Africa from Senegal to northern Nigeria.

Acacia arabica is the gum-Arabic tree of India, but yields a gum inferior to the true gum-Arabic.

Medicinal uses

Many Acacia species have important uses in traditional medicine. Most all of the uses have been shown to have a scientific basis, since chemical compounds found in the various species have medicinal effects. In Ayurvedic medicine, Acacia nilotica is considered a remedy that is helpful for treating premature ejaculation. An astringent medicine, called catechu or cutch, is procured from several species, but more especially from Acacia catechu, by boiling down the wood and evaporating the solution so as to get an extract.^[2]

Ornamental uses

A few species are widely grown as ornamentals in gardens; the most popular perhaps is Acacia dealbata (Silver Wattle), with its attractive glaucous to silvery leaves and bright yellow flowers; it is erroneously known as "mimosa" in some areas where it is cultivated, through confusion with the related genus Mimosa.

Another ornamental acacia is Acacia xanthophloea (Fever Tree). Southern European florists use Acacia baileyana, Acacia dealbata, Acacia pycnantha and Acacia retinodes as cut flowers and the common name there for them is mimosa.^[3]

Ornamental species of acacia are also used by homeowners and landscape architects for home security purposes.^[4][5] The sharp thorns of some species deter unauthorized persons from entering private properties, and may prevent break-ins if planted under windows and near drainpipes. The aesthetic characteristics of acacia plants, in conjunction with their home security qualities, makes them a considerable alternative to artificial fences and walls.

Paints

The ancient Egyptians used Acacia in paints.^[6]

Perfume

Acacia farnesiana is used in the perfume industry due to its strong fragrance. The use of Acacia as a fragrance dates back centuries. In The Bible, burning of acacia wood as a form of incense is mentioned several times.

Symbolism and ritual

The Acacia is used as a symbol in Freemasonry, to represent purity and endurance of the soul, and as funerary symbolism signifying resurrection and immortality.

Several parts (mainly bark, root and resin) of Acacia are used to make incense for rituals. Acacia is used in incense mainly in India, Nepal, Tibet and China. Smoke from Acacia bark is thought to keep demons and ghosts away and to put the gods in a good mood. Roots and resin from Acacia are combined with rhododendron, acorus, cytisus, salvia and some other components of incense. Both people and elephants like an alcoholic beverage made from acacia fruit.^[7] According to Easton's Bible Dictionary, the Acacia tree may be the “burning bush” (Exodus 3:2) which Moses encountered in the desert

In the Quran 56:29, the acacia are mentioned as the flowers that companions in heaven will be wearing.

Tannin

The bark of various Australian species, known as wattles, is very rich in tannin and forms an important article of export; important species include Acacia pycnantha (Golden Wattle), Acacia decurrens (Tan Wattle), Acacia dealbata (Silver Wattle) and Acacia mearnsii (Black Wattle).

Tannin Content of Various Acacia Species

	Bark	Dried Leaves	Seed Pods
Species	Tannins [%]	Tannins [%]	Tannins [%]
Acacia albida	2-28%[8]		5-13%[8]
Acacia cavenia			32%[9]
Acacia dealbata	19.1%[10]
Acacia decurrens	37-40%[10]
Acacia farnesiana			23%[10]
Acacia mearnsii	25-35%[8]
Acacia melanoxylon	20%[9]
Acacia nilotica	18-23%*[8]
Acacia penninervis	18%[9]
Acacia pycnantha	30-45%[9]	15-16%[9]
Acacia saligna	21.5%[10]

*Inner bark

Black Wattle is grown in plantations in South Africa. Most Australian acacia species introduced to South Africa have become an enormous problem, due to their naturally aggressive propagation. The pods of Acacia nilotica (under the name of neb-neb), and of other African species are also rich in tannin and used by tanners.

Wood

Most acacia species are used for valuable timber; such are Acacia melanoxylon (Blackwood) from Australia, which attains a great size; its wood is used for furniture, and takes a high polish; and Acacia omalophylla (Myall Wood, also Australian), which yields a fragrant timber, used for ornamental purposes. Acacia seyal is thought to be the Shittah-tree of the Bible, which supplied shittim-wood. According to the Book of Exodus, this was used in the construction of the Ark of the Covenant. Acacia koa from the Hawaiian Islands and Acacia heterophylla from Réunion island are both excellent timber trees.

Approximate Wood Densities of Various Acacia Species

	Density	Density	Heartwood Density	Sapwood Density
Species	[g/cm³]	[kg/m³]	[kg/m³]	[kg/m³]
Acacia acuminata		1040[11]
Acacia amythethophylla			1170[12]
Acacia catechu	0.88[13]
Acacia confusa	0.69-0.75[13]
Acacia erioloba			1230[12]
Acacia galpinii			800[12]
Acacia goetzii				1025[12]
Acacia karoo			800[12]
Acacia leucophloea	0.76[13]
Acacia mellifera subsp. mellifera			1100[12]
Acacia nilotica	0.70[13]		1170[12]
Acacia nilotica subsp. adstringens	0.827-0.945[12]
Acacia nilotica subsp. nilotica	0. 80[12]		1170[12]
Acacia polyacantha subsp. campylacantha			705[12]
Acacia sieberiana		655[12]

In Indonesia (mainly in Sumatra) and in Malaysia (mainly in Sarawak) plantations of Acacia mangium are being established to supply pulpwood to the paper industry.

Phytochemistry of Acacias

Alkaloids

As mentioned previously, Acacias contain a number of organic compounds that defend them from pests and grazing animals.^[1] Many of these compounds are psychoactive in humans. The alkaloids found in Acacias include Dimethyltryptamine (DMT) and N-methyltryptamine (NMT). The plant leaves, stems and/or roots are sometimes made into a brew together with some MAOI-containing plant and consumed orally for healing, ceremonial or religious uses. Egyptian mythology has associated the acacia tree with characteristics of the tree of life (cf. article on the Legend of Osiris and Isis).

Acacias Known to Contain Psychoactive Alkaloids

Acacia acuminata	Up to 1.5% alkaloids, mainly consisting of tryptamine in leaf[14]
Acacia adunca	β-methyl-phenethylamine, 2.4% in leaves[15]
Acacia alpina	Active principles in leaf[16]
Acacia aneura	Psychoactive.[17][18] Ash used in Pituri.[19] Ether extracts about 2-6% of the dried leaf mass.[20]
Acacia angustifolia	Psychoactive,[17] Tryptamines
Acacia angustissima	β-methyl-phenethylamine[21], NMT and DMT in leaf (1.1-10.2 ppm)[22]
Acacia aroma	Tryptamine alkaloids.[23] Significant amount of tryptamine in the seeds.[24]
Acacia auriculiformis	5-MeO-DMT in stem bark[25]
Acacia baileyana	0.02% tryptamine and β-carbolines, in the leaf, Tetrahydroharman[16][26][27]
Acacia beauverdiana	Psychoactive[28] Ash used in Pituri.[19]
Acacia berlandieri	DMT, amphetamines, mescaline, nicotine[29]
Acacia catechu	DMT[30] and other tryptamines in leaf, bark
Acacia caven	Psychoactive[17]
Acacia chundra	DMT and other tryptamines in leaf, bark
Acacia colei	DMT[31]
Acacia complanata	0.3% alkaloids in leaf and stem, almost all N-methyl-tetrahydroharman, with traces of tetrahydroharman, some of tryptamine[32][33][34]
Acacia concinna	Nicotine[35]
Acacia confusa	DMT & NMT in leaf, stem & bark 0.04% NMT and 0.02% DMT in stem.[16] Also N,N-dimethyltryptamine N-oxide[36]
Acacia constricta	β-methyl-phenethylamine[21]
Acacia coriacea	Psychoactive[17][18] Ash used in Pituri.[19]
Acacia cornigera	Psychoactive,[17] Tryptamines[7]
Acacia cultriformis	Tryptamine, in the leaf, stem[16] and seeds.[24] Phenethylamine in leaf and seeds[24]
Acacia cuthbertsonii	Psychoactive[28]
Acacia decurrens	Psychoactive,[17] but less than 0.02% alkaloids[27]
Acacia delibrata	Psychoactive[28]
Acacia falcata	Psychoactive,[28] but less than 0.02% alkaloids[27]
Acacia farnesiana	Traces of 5-MeO-DMT[37] in fruit. β-methyl-phenethylamine, flower.[38] Ether extracts about 2-6% of the dried leaf mass.[39] Alkaloids are present in the bark[40] and leaves.[41] Amphetamines and mescaline also found in tree.[7]
Acacia filiciana	Psychoactive[17]
Acacia floribunda	Tryptamine, phenethylamine,[42] in flowers[24] other tryptamines,[43] phenethylamines[44]
Acacia georginae	Psychoactive,[17] plus deadly toxins
Acacia greggii	N-methyl-β-phenethylamine,[21] phenethylamine[1]
Acacia harpophylla	Phenethylamine, hordenine at a ratio of 2:3 in dried leaves, 0.6% total[15]
Acacia holoserica	Hordenine, 1.2% in bark[15]
Acacia horrida	Psychoactive[17]
Acacia implexa	Psychoactive[45]
Acacia jurema	DMT, NMT
Acacia karroo	Psychoactive
Acacia kempeana	Psychoactive[17][18]
Acacia kettlewelliae	1.5[15]-1.88%[46] alkaloids, 92% consisting of phenylethylamine.[15] 0.9% N-methyl-2- phenylethylamine found a different time.[15]
Acacia laeta	DMT, in the leaf[16]
Acacia lingulata	Psychoactive[17][18]
Acacia longifolia	0.2% tryptamine in bark, leaves, some in flowers, phenylethylamine in flowers,[42] 0.2% DMT in plant.[47] Histamine alkaloids.[27]
Acacia longifolia var. sophorae	Tryptamine in leaves, bark[24]
Acacia macradenia	Tryptamine[24]
Acacia maidenii	0.6% NMT and DMT in about a 2:3 ratio in the stem bark, both present in leaves[16]
Acacia mangium	Psychoactive[17]
Acacia melanoxylon	DMT, in the bark and leaf,[48] but less than 0.02% total alkaloids[27]
Acacia mellifera	DMT, in the leaf[16]
Acacia nilotica	DMT, in the leaf[16]
Acacia nilotica subsp. adstringens	Psychoactive, DMT in the leaf
Acacia obtusifolia	Tryptamine,[43] DMT, NMT, other tryptamines,[49] 0.4-0.5% in dried bark, 0.07% in branch tips.[50]
Acacia oerfota	Less than 0.1% DMT in leaf,[51][26] NMT
Acacia penninervis	Psychoactive[28]
Acacia phlebophylla	0.3% DMT in leaf, NMT[16]
Acacia platensis	Psychoactive[17]
Acacia podalyriaefolia	Tryptamine in the leaf,[16] 0.5% to 2% DMT in fresh bark, phenethylamine, trace amounts[42]
Acacia polyacantha	DMT in leaf[16] and other tryptamines in leaf, bark
Acacia polyacantha ssp. campylacantha	Less than 0.2% DMT in leaf, NMT; DMT and other tryptamines in leaf, bark[52]
Acacia prominens	phenylethylamine, β-methyl-phenethylamine[42][15]
Acacia pruinocarpa	Psychoactive[17][18] Ash used in Pituri.[19]
Acacia pycnantha	Psychoactive,[17] but less than 0.02% total alkaloids[27]
Acacia retinodes	DMT, NMT,[53] nicotine,[7] but less than 0.02% total alkaloids found[27]
Acacia rigidula	DMT, NMT, tryptamine, amphetamines, mescaline, nicotine and others[54]
Acacia roemeriana	β-methyl-phenethylamine[21]
Acacia salicina	Psychoactive[17][18] Ash used in Pituri.[19]
Acacia sassa	Psychoactive[17]
Acacia schaffneri	β-methyl-phenethylamine, Phenethylamine[1] Amphetamines and mescaline also found.[7]
Acacia schottii	β-methyl-phenethylamine[21]
Acacia senegal	Less than 0.1% DMT in leaf,[16] NMT, other tryptamines. DMT in plant,[38] DMT in bark.[24]
Acacia sieberiana	DMT, in the leaf[16]
Acacia simplex	DMT and NMT, in the leaf, stem and trunk bark, 0.81% DMT in bark, MMT[55][16]
Acacia taxensis	β-methyl-phenethylamine[21]
Acacia tenuifolia	Psychoactive[17]
Acacia tenuifolia var. producta	Psychoactive[17]
Acacia tortilis	DMT, NMT, and other tryptamines[49]
Acacia verek	Psychoactive.[17] Less than 0.1% DMT in leaf, NMT, other tryptamines
Acacia vestita	Tryptamine, in the leaf and stem,[16] but less than 0.02% total alkaloids[27]
Acacia victoriae	Tryptamines[43], 5-MeO-alkyltryptamine[24]
Acacia visco	Psychoactive[17]

List of Acacia Species Having Little or No Alkaloids in the Material Sampled:^[27]

0% C 0.02%, C...Concentration of Alkaloids [%]

• Acacia acinacea
• Acacia baileyana
• Acacia decurrens
• Acacia dealbata
• Acacia mearnsii
• Acacia drummondii
• Acacia elata
• Acacia falcata
• Acacia leprosa
• Acacia linearis
• Acacia melanoxylon
• Acacia pycnantha
• Acacia retinodes
• Acacia saligna
• Acacia stricta
• Acacia verticillata
• Acacia vestita

Cyanogenic glycosides

Nineteen different species of Acacia in the Americas contain cyanogenic glycosides, which, if exposed to an enzyme which specifically splits glycosides, can release hydrogen cyanide (HCN) in the acacia "leaves."^[56] This sometimes results in the poisoning death of livestock.

If fresh plant material spontaneously produces 200 ppm or more HCN, then it is potentially toxic. This corresponds to about 7.5 μmol HCN per gram of fresh plant material. It turns out that, if acacia "leaves" lack the specific glycoside-splitting enzyme, then they may be less toxic than otherwise, even those containing significant quatities of cyanic glycosides.^[27]

Some Acacia species containing cyanogens:

• Acacia giraffae
• Acacia cunninghamii
• Acacia sieberiana
• Acacia sieberiana var. woodii^[57]

Species

There are over 1,300 species of Acacia. See List of Acacia species for a more complete listing.

Famous acacia

Perhaps the most famous acacia is the Arbre du Ténéré in Niger. The reason for the tree's fame is that it used to be the most isolated tree on in the world, approximately, 400 km far from any other tree. The tree was knocked down by a truck driver in 1973. It has also been suggested that the altar in Exodus 27:1 (KJV; [2]) was made of a form of acacia or "shittim wood" - the Hebrew equivalent.