Galapagos Species Database

The Galapagos Species Database shares the information about the species from our Natural History Collections.

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Vachellia nilotica (L.) P.J.H.Hurter & Mabb.

Algarrobo, Acacia espinosa, Acacia, Gum arabic tree, Nile acacia, Prickly acacia

Acacia nilotica is a shrub or small tree of 7-15 m high. Stems are up to 7 m long, branching almost from the base; whitish and pubescent when young, they become darker, rough and fissured with age. Leaves are alternate, bipinnate, consisting of 3-10 pairs of primary leaf segments, each bearing 10-25 pairs of small linear-oblong leaflets; a petiolar gland occurs between the 2 pairs of segments closest to the stem; a pair of stout stipular spines can be found at the base of each leaf on younger stems but may be absent on older stems. Flowers are bright yellow, numerous, in fluffy globular heads, usually in clusters of 2-6. The fruit is a gray-green, softly hairy, flattened pod, strongly constricted between each seed. Seeds, 6-16 per pod, are depressed and globular. A. nilotica forms a deep and extensive root system on dry sites, the tap root developing first and then the lateral roots. Acacia nilotica is easy to recognize by its feathery leaves, bright yellow flowers in round heads, straight stipular spines that are often slightly deflexed, and pods constricted between the seeds.

Taxonomy

Domain
Eukaryota

Kingdom
Plantae

Phylum
Magnoliophyta

Class
Magnoliopsida (= Dicotyledoneae)

Order
Fabales

Family
Fabaceae

Genus
Vachellia

Species
nilotica

Taxon category: Accepted

Syn.: Acacia nilotica (L.) Willd. ex Delile (POWO, 2022); Mimosa nilotica L. Acacia nilotica is generally accepted as a single, extremely variable species, divided into nine subspecies.

Origin: Introduced - established

Introduction

Year of first record: 1963

Mode of introduction: Intentional

Introduced status: Naturalized

Invasive status: Potentially Invasive

Distribution

Map of specimen collection localities or observation records for this species in our collections database.

Distribution: Santa Cruz, San Cristobal On Santa Cruz, found at two sites in Puerto Ayora. On San Cristobal, reported on one site in Puerto Baquerizo Moreno.

References

  • Agriculture & Resource Management Council Australia & New Zealand, Australian & New ZealandEnvironment & Conservation Council and Forestry Ministers (2000) Weeds of National Significance Prickly Acacia (Acacia nilotica) Strategic Plan. National Weeds Strategy Executive Committee, Launceston.
  • Bolton, M. P. James, P.A. (1985) A survey of prickly acacia (Acacia nilotica) in five western Queensland shires. Townsville. Qld.: Stock Routes and Rural Lands Protection Board, lv.
  • Carter JO (1994) Acacia nilotica: a tree legume out of control’, in Forage Tree Legumes in Tropical Agriculture, RC Gutteridge & HM Shelton eds, CAB International, Wallingford, UK, pp. 338–51.
  • Rentería, J. L. Atkinson, R. & Buddenhagen, C. (2007) Plan de manejo para la erradicación de Acacia nilotica, especie invasora de limitada distribución en la isla Santa Cruz. Fundación Charles Darwin.
  • Sheik M.I. (1989) Acacia nilotica (L) Willd. ex Del.: its production, management and utilization, Pakistan. Field Document FAO Regional Office for Asia and the Pacific, No. 20, 45 pp.; 50 ref. http://www.cabi.org/isc/abstract/19930666232
  • Sarah Reichard Lizbeth Seebacher (2009) Weed Risk Assessment for Acacia nilotica (L.) Willd. ex Delil, Addendum to the report: Analysis and Assessment of the Invasive risk of Acacia nilotica;. University of Washington, College of Forest Resources, Center for Urban Horticulture.
  • Royal Botanic Gardens, Kew (2022) Plants of the world online POWO (2022): Plants of the world online. Published on the Internet; Https://powo.science.kew.org/
  • Ebinger, J. Seigler, D. & Clarke, H. (2000) Taxonomic revision of South American species of the genus Acacia subgenus Acacia (Fabaceae: Mimosoideae) Systematic Botany, 25(4):588-617.

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This page should be cited as follows:

"Galapagos Species Database, Vachellia nilotica", dataZone. Charles Darwin Foundation, https://datazone.darwinfoundation.org/en/checklist/?species=24714. Accessed 21 May 2025.