Acacia farnesiana

''Vachellia farnesiana'', also known as ''Acacia farnesiana'', and previously ''Mimosa farnesiana'', commonly known as sweet acacia, huisache, or needle bush, is a species of shrub or small tree in the legume family, Fabaceae. Its flowers are used in the perfume industry.

Description

The plant is deciduous over part of its range, but evergreen in most locales. Growing from multiple trunks, it reaches a height of . The bark is whitish gray. The base of each leaf is accompanied by a pair of thorns on the branch. The dark brown fruit is a seed pod.

Taxonomy

Taxonomic history

It was first described by Europeans under the name ''Acacia Indica Farnesiana'' in 1625 by Tobias Aldini from plants grown in Rome in the Farnese Gardens from seed collected in Santo Domingo, in what is now the Dominican Republic, which germinated in 1611. Aldini included an illustration of the plant, which he contrasted with an illustration of the first known ''Acacia''; ''Acacia nilotica''. This first (European) illustration of the plant was later designated as the (lecto-)type. In 1753, Carl Linnaeus used Aldini's work as basis for his taxon ''Mimosa farnesiana''. In 1806 Carl Ludwig Willdenow moved this taxon to the genus ''Acacia''.

Partly due to its wide distributional range, the taxon has attracted many synonyms. Especially in the United States, the taxonomy has been confused.

In 1809, Willdenow described ''Acacia acicularis'' from Central America collected and named during Humboldt and Bonpland's scientific expedition to the Americas. ''Acacia ferox'' was described in 1843 in Belgium from collections in Mexico. ''Acacia lenticellata'' was described in 1859 for the plants found growing throughout Australia.

In the ''Prodromus Florae Peninsulae Indiae Orientalis'' of 1834, Wight & Arnott, attempted to split the burgeoning genus ''Acacia'' by moving a number of the ''Acacia'' species growing in India to the new genus ''Vachellia''.

This was not widely followed, nonetheless in 1933, Small verified Alexander's name ''Vachellia densiflora'' for plants growing in Louisiana, and awarded ''V. peninsularis'' and ''V. insularis'' to different populations of the plants growing in Florida.

In 1936, Cory moved ''Vachellia densiflora'' to ''Acacia densiflora'', but as this name had already been used for another taxon, and was therefore invalidated ''sensu'' Cory, in 1969, this taxon was renamed ''A. smallii'' by Isely. In 1948, F. J. Herm. synonymised ''Vachellia peninsularis'' and ''V. insularis'' under ''Acacia pinetorum''.

In 1933, M. E. Jones named plants he collected in Mexico ''Pithecellobium minutum''. This taxon was moved to ''Acacia minuta'' by R.'' ''Mitchel Beauchamp in 1980. Beauchamp also subsumed ''A. smallii'' under ''A. minuta'' subsp. ''densiflora'', although this was not widely followed.

''Acacia smallii'' was used in the U.S. for the 'native' ''A. farnesiana'' growing in the drylands west of Louisiana, but at the same time, the taxon ''A. farnesiana'' was recognised in the U.S. for purportedly imported non-native plants originally cultivated in the Southeastern U.S. as ornamentals and later thought naturalised there. Additionally, in Florida, ''A. pinetorum'' was recognised as a rare endemic native.

A paper in 1989 by H. D. Clarke, D. S. Seigler and J. E. Ebinger finally cleared up some of this confusion, synonymising ''Acacia smallii'' and a number of other taxa under the nominate form of ''A. farnesiana'', under which they also included all of the plants growing outside of the Americas. In the same paper, they recognised ''A. farnesiana'' var. ''guanacastensis'' from herbarium collections made by D. H. Janzen in 1976 in Guanacaste, Costa Rica.Clarke, H.D., Seigler, D.S., Ebinger, J.E. 1989; 'Acacia farnesiana (Fabaceae: Mimosoideae) and Related Species from Mexico, the Southwestern U.S., and the Caribbean' Systematic Botany 14 549-564 This taxon was later elevated to species status as ''A. guanacastensis'' by the same three in 2000 and later moved to ''Vachellia guanacastensis'' by Seigler and Ebinger in 2006.

''Acacia pinetorum'' was subsumed under ''A. farnesiana'' as ''A. farnesiana'' subsp. ''pinetorum'' in 2002 by Clarke, Seigler and Ebinger (rendering the nominate form ''A. farnesiana'' subsp. ''farnesiana''). Seigler and Ebinger later reclassified this as ''Vachellia farnesiana'' var. ''pinetorum'' in 2005.

Infraspecific diversity

''Acacia farnesiana'' var. ''guanacastensis'' is primarily distinguished by larger leaflets. It remains controversial; most taxonomic authorities in Mexico and Central America recognise this taxon as a full species under either ''A. guanacastensis'' or ''Vachellia guanacastensis'', the ''Árboles nativos e introduciados de El Salvador'' of 2009 subsumed it under ''Acacia farnesiana''. It is recognised as present in Costa Rica, El Salvador, Guatemala, Nicaragua, and the southern Gulf and southwestern regions of Mexico by the ''Kew World Checklist of Selected Plant Families'' (2018), but whether the taxon as recognised by the different authorities replaces ''Acacia farnesiana'' in Central America (but not the Caribbean or South America) or exists sympatrically remains unclear. This has implications for the classification of the extra-American distribution of ''A. farnesiana'' as the populations growing in Australia and the Philippines have recently (2017) been shown to derive from ancient Central American origins.

''Acacia pinetorum'', the pineland acacia or pineland wattle, is also disputed. The International Legume Database and Information Service continues to recognise ''A. pinetorum'', while the U.S. Department of Agriculture recognises ''V. farnesiana'' var. ''pinetorum''.

In France, two old cultivars have been developed for the perfume industry. These were also recognised as varieties at one time.

Etymology

The specific name ''farnesiana'' honors Odoardo Farnese (1573–1626) of the notable Italian Farnese family, which after 1550, under the patronage of Cardinal Alessandro Farnese, maintained some of the first private European botanical gardens in Rome, the Farnese Gardens, in the 16th and 17th centuries.

This acacia was first described from these gardens, imported to Italy from Santo Domingo, in what is now the Dominican Republic.

Analysis of essences of the floral extract from this plant, long used in perfumery, resulted in the name for the sesquiterpene biosynthetic chemical farnesol, found as a basic sterol precursor in plants, and cholesterol precursor in animals.

The name huisache of Mexico and Texas is derived from Nahuatl and means "many thorns".
The Australian name needle bush came about because of the numerous thorns distributed along its branches.

Distribution and habitat

Of all ''Acacia'' species, this plant has the greatest distribution. It was first described by Europeans in 1625 by Tobias Aldini from plants grown from seed collected in Santo Domingo, in what is now the Dominican Republic. The native range of ''V. farnesiana'' has been or is sometimes disputed. While the point of origin is thought to be the Caribbean, the Guianas, Mexico, and/or Central America, the species has a pantropical distribution incorporating most of the Americas (from the Southern U.S. to Chile, excluding the Amazon), most of Australia, much of Africa, southern Europe, and southern Asia. In the Caribbean, it is present from the Bahamas and Cuba south to Trinidad, Curaçao, and Aruba, where in it is believed to be native to Hispaniola and certainly Cuba, but possibly native or naturalised elsewhere. In the U.S., it is thought to be native to southern Texas, southern New Mexico, southern Arizona, and southern California, but perhaps naturalized in southern Louisiana, coastal Mississippi, coastal Alabama, coastal Georgia, and southern Florida. Whether the extra-American distribution is natural (the seed pods have probably floated across the Pacific) or anthropogenic remains disputed. It was introduced to Europe, the Middle East, India, Africa, and recently Gran Canaria and Hawaii. It has long been thought to be native to the Philippines and Australia, having spread there by natural means, because plants were collected there before colonisation in 1788, it was distributed throughout the country, indigenous knowledge on the plant is extensive, and 2017 DNA investigations show this as most likely. In Australia, however, the government now considers it as non-native or even invasive.

The plant prefers full sunlight in a tropical climate.

Ecology

Deer and peccaries eat its fruit, various birds use the plant for nesting and cover, and insects eat the nectar from its flowers. If disturbed, it readily resprouts. It thrives in dry, saline, or sodic soils.

It is considered a serious pest plant in parts of Australia, as it interferes with cattle-ranching operations. It readily spreads in commercial grazing pastures, especially along creeks, which might affect ease of transport for farmers, complicates muster, and can damage farm machinery. The seeds are dispersed by cattle after they eat the nutritious pods, and growth is promoted by overgrazing. Numerous herbicides are used to control it on ranches; chemical control is the only way to kill it. The plant has been spread to many new locations as a result of human activity, and it is considered a serious weed in Fiji, where locals call it Ellington's curse.

Uses

Perfume

The flowers are processed through distillation to produce a perfume called cassie, which has been described as "delicious". It is widely used in the perfume industry in Europe. Flowers of the plant provide the perfume essence from which the biologically important sesquiterpenoid farnesol is named.

Scented ointments from cassie are made in India.

Gum

It exudes a gum, which is sometimes collected.

Tanning leather

The bark is used for its tannin content. The concentration of tannin in the seed pods is about 23%. Highly tannic barks are common in general to acacias. Extracts of many are used in medicine for this reason.

Food

The plant's young leaves, flowers, and seed pods are edible raw or cooked.

Fodder and forage

The foliage is a significant source of forage in much of its range, with a protein content around 18%.
The tree makes good forage for bees.
The seed pods are readily eaten by livestock.

Ornamental

This drought-tolerant species is often used in xeriscaping in Texas.

Dyes and inks

A black pigment is extracted from the bark and fruit.

Traditional medicine

In Brazil, some people use the seeds of ''V. farnesiana'' to kill rabid dogs. ''V. farnesiana'' has been used in Colombia to treat malaria, and in one ''in vitro'' study, an ethanol extract from the leaves showed some activity against the malarial pathogen ''Plasmodium falciparum'' with an IC₅₀ value of 1 to 2 microgram/millilitre (as did almost everything tested), though it showed no activity in animal models or a ferriprotoporphyrin biomineralization inhibition test. In the Philippines the leaves are traditionally rubbed on the skin to treat skin diseases in livestock. In Malaysia, an infusion of the plant's flowers and leaves is mixed with turmeric for post-partum treatment.

Gallery

References

External links

Interactive Distribution Map of ''Vachellia farnesiana''

Acacia farnesiana (L.) Willd.
Medicinal Plant Images Database (School of Chinese Medicine, Hong Kong Baptist University)
Native Plants of South Texas: Sweet Acacia (''Acacia farnesiana'')
University of Arizona Pima County Cooperative Extension

{{Taxonbar, from=Q932729

farnesiana
Trees of Central America
Trees of Mexico
Trees of the Southwestern United States
Trees of the South-Central United States
Forages
Shrubs
Entheogens
Drought-tolerant trees