Acacia farnesiana
(huisache)

Preferred Common Name

• huisache

Variety

• Acacia farnesiana var. farnesiana
• Acacia farnesiana var. guanacastensis Clarke, Seigler & Ebinger

Other Scientific Names

• Acacia minuta (M.E. Jones) Beauchamp
• Acacia smallii Isely
• Mimosa farnesiana L.
• Pithecellobium minutum M.E. Jones
• Vachellia densiflora Alexander ex Small
• Vachellia farnesiana (L.) Wight & Arn.

International Common Names

• English: Cassie flower; Fragrant acacia; sweet acacia
• Spanish: aroma; Aromo creole; Aromo macho; Cachito; Carbonero; cashia; espinial; huisache; rayo
• French: Acacie odorante; Cassier
• Portuguese: esponjeira

Local Common Names

• Australia: mimosa bush; needle bush
• Bangladesh: Guva-babul
• Brazil: espinilha; espinilho; esponjeira
• Cuba: aroma amarilla
• El Salvador: espino blanco; espino ruco
• Fiji: ban baburi; Ellington's curse; vaivai vakavotona
• Germany: Aber falsche Bezeichnung; Antillen Akazie; Echte Akazie; Mimose gebraeuchliche; Schwammbaum
• India: Dei-babul; Gabur; gand-babul; gukikar; jali; kankar; Kankri; passi-babul; vilaiti-babul; vilayati-kikar
• India/Assam: Tarua-kadam
• India/Tamil Nadu: Kadivel; vedda vala
• Italy: acacia farnese
• Mexico: huisache
• USA: opoponax
• USA/Hawaii: klu; popinac

EPPO code

• ACAFA (Acacia farnesiana)

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Fabales
•                         Family: Fabaceae
•                             Subfamily: Mimosoideae
•                                 Genus: Acacia
•                                     Species: Acacia farnesiana

A. farnesiana is one of few New World species of the genus, thought to have originated in Central America, and similar in morphology and habitat preferences to the South American A. caven. Suggested revisions of the genus by Pedley which would transfer all Australian species to the new genus Racosperma and some African species to Senegalia, would leave these New World species and their Africa and Asia relatives unchanged in taxonomical terms. It has a large number of common names, known widely in North America by its common Spanish name of 'huisache', more often in Europe by names describing the sweet fragrance of its flowers.

A. farnesiana is a spinescent shrub, or rarely a small tree, 2-7 m tall with several slender stems and long thin branches growing from ground level. University of Hawaii Botany Department (1998) describe A. farnesiana as thorny, deciduous, growing to 4 m in height. The following description is adapted from Gilman and Watson (1993) and Watson and Dallwitz (1999). A tall, semi-evergreen shrub or small tree with feathery, fine divided leaflets of a soft, medium, green colour. The slightly rough stems are a rich chocolate brown or grey, possessing long, sharp, multiple thorns. Branches glabrous or nearly, purplish to grey, with very small glands; stipules spinescent, usually short, up to 1.8 cm long, rarely longer, never inflated; leaves twice pinnate, with a small gland on petiole and sometimes one on the rachis near top of pinnae; pinnae 2-8 pairs, leaflets 10-12 pairs, minute, 2-7 mm long, 0.75-1.75 mm wide. The small, yellow, puff-like flowers are very fragrant and appear in clusters in late winter then sporadically after each new flush of growth providing nearly year-round bloom. Flowers glabrous, leathery; in axillary pedunculate heads, calyx and corolla glabrous, scented. Pod indehiscent, straight or curved, 4-7.5 cm long, about 1.5 cm wide, subterete and turgid, dark brown to blackish, glabrous, finely longitudinally striate, pointed at both ends; seeds chestnut-brown, in two rows, embedded in a dry spongy tissue, 7-8 mm long, ca 5.5 mm broad, smooth, elliptic, thick, only slightly compressed; areole 6.5-7 mm long, 4 mm wide. The persistent fruits have a glossy coat and contain seeds which are cherished by birds and other wildlife.

A. farnesiana is the most widely distributed species of the genus, now naturalized in many regions of the tropics and subtropics from its origins in tropical America. A contributing factor is its wide adaptability and tolerance of drought, frost, fire, saline soils and other growth-limiting conditions. Holm et al. (1991) report A. farnesiana as a serious weed in Iraq, a principal weed in Australia, Fiji, Indonesia, Mexico and Paraguay, a common weed in Hawaii and the Philippines and present as a weed in numerous other countries. University of Hawaii Botany Department (1998) report that it is present on all the Hawaiian islands, with dense infestations on the islands of Lualualei, O'ahu, Lihau and Maui. In Puerto Rico, it is common and spreads rapidly, occupying more than 1000 hectares in dry coastal areas and offshore islands (Francis and Liogier, 1991), classed it as a category 3 problem plant especially in grasslands.

Soil drainage

• free

Soil reaction

• acid
• alkaline
• neutral

Soil texture

• heavy
• light
• medium

Special soil tolerances

• saline

A. farnesiana is primarily dispersed by animals, notably livestock. Ungulates which feed on the pods can disperse A. farnesiana seeds (University of Hawaii Botany Department, 1998). In its native North America the seeds attract a variety of wildlife in its native range including birds, squirrels and other mammals (Gilman and Watson, 1993).

Regarding long-distance dispersal, A. farnesiana has been widely introduced over a very long period, being one of the earliest Acacia species to have been introduced outside its native range. It has become naturalized in many countries, and so intentional introduction is likely to be the cause of future instances of invasion.

As a weed of grasslands, A. farnesiana has an economic impact on the livestock industries where invasive, by reducing available forage and restricting access to watering points and hampering mustering. However, no quantitative figures are reported.

Impact on Habitats

The habit of forming dense thickets is likely to shade out native vegetation and result in changes in nutrient cycling.

Impact on Biodiversity

No direct references were encountered but A. farnesiana is likely to shade out native flora. The fruits are eaten by many birds and mammals in the native range and are likely to be eaten and potentially dispersed by birds and mammals in the exotic range.

• Invasive in its native range
• Proved invasive outside its native range
• Highly adaptable to different environments
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Has high reproductive potential
• Has propagules that can remain viable for more than one year

• Damaged ecosystem services
• Ecosystem change/ habitat alteration
• Negatively impacts agriculture
• Reduced native biodiversity

• Competition - monopolizing resources
• Competition (unspecified)
• Produces spines, thorns or burrs

• Highly likely to be transported internationally deliberately
• Difficult/costly to control

A. farnesiana is a true multipurpose species, with all parts of the plants being used as a resource. Floral essential oils of A. farnesiana are used in perfumes; the gum is used as a substitute for gum arabic; bark and pods are used for dyeing and tanning; the pods and leaves are forage for livestock; and extracts from the bark, leaves, flowers and green pods are used in traditional medicine in many areas. The wood makes an excellent fuel and can be used for posts, tool handles, turnery and to make furniture. It is also used as an ornamental species, for example in India. Unripe (green) pods, when broken, yield a sticky substance which is used as a glue. It is, however, principally noted as a dryland forage species, with the foliage and the pods being palatable and nutritious. It is a nitrogen-fixing species and has also been used for erosion control.