Vachellia nilotica

This species of tree is the type species of the Linnaean genus Acacia, which derives its name from Ancient Greek: ἀκακία, akakía, the name given by early Greek botanist-physician Pedanius Dioscorides (ca. 40–90) to this tree as a medicinal, in his book Materia Medica.[9] The genus Acacia was long known not to be taxonomically monophyletic, and despite being the type species of that genus, A. nilotica has since been moved to the genus Vachellia, with the genus name Acacia being reserved for Australian species; the principle of priority, which would normally prevent such a taxonomic change, was waived with a majority vote by the International Botanical Congress in 2005. The renaming of the traditional Acacia to Vachellia remains controversial, especially in Africa, where V. nilotica is an iconic species and is widely referred to as the acacia.[10] For the new classification of this and other species historically classified under genus Acacia, see Acacia.

The genus name Acacia derives from Ancient Greek: ἀκακία, which may come from the Ancient Greek word for its characteristic thorns, ἄκις, ákis, "thorn",[11] or may have been borrowed from Pre-Greek.[12] The specific epithet nilotica was probably given by Linnaeus from this tree's originally known range along the Nile river. In Australia the tree is known as a prickly acacia,[13] despite usurping Dioscorides' two millennia-old etymology, the Australian species classified as Acacia in Australia do not have thorns.

Spring blossoms at Hodal in Faridabad District of Haryana, India

Acacia nilotica or Vachellia nilotica is a tree 5–20 m high with a dense spheric crown, stems and branches usually dark to black coloured, fissured bark, grey-pinkish slash, exuding a reddish low quality gum. The tree has thin, straight, light, grey spines in axillary pairs, usually in 3 to 12 pairs, 5 to 7.5 cm (3 in) long in young trees, mature trees commonly without thorns. The leaves are bipinnate, with 3–6 pairs of pinnulae and 10–30 pairs of leaflets each, tomentose, rachis with a gland at the bottom of the last pair of pinnulae. Flowers in globulous heads 1.2–1.5 cm in diameter of a bright golden-yellow color, set up either axillary or whorly on peduncles 2–3 cm long located at the end of the branches. Pods are strongly constricted, hairy, white-grey, thick and softly tomentose. Its seeds number approximately 8000/kg.[14]

Acacia nilotica or Vachellia nilotica is native from Egypt, across the Maghreb and Sahel, south to Mozambique and KwaZulu-Natal, South Africa, and east through the Arabian Peninsula to the Indian subcontinent and Burma. It has become widely naturalised outside its native range including Zanzibar and Australia.[15] It is spread by livestock.[13]

Two new antiprotozoal diterpenes have been isolated from the root bark of Acacia nilotica [23]

There are 5000–16000 seeds/kg.[24]

• 
  Vachellia nilotica, Village Behlolpur, Punjab, India
• 
  village Chaparr Chirri, Mohali, Punjab, India
• 
  Compound leaf, seed, flower and seed pod

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• Carter, J.O. (1998). "7.2 Acacia nilotica: a Tree Legume out of Control". In Gutteridge, Ross C.; Shelton, H. Max (eds.). Forage Tree Legumes in Tropical Agriculture. The Tropical Grassland Society of Australia. ISBN 978-0-9585677-1-8.
• "Vachellia nilotica (as Acacia nilotica subsp. indica (Benth.) Brenan)". FloraBase the West Australian Flora.
• Vachellia nilotica (as Acacia nilotica) (www.frienvis.nic.in)

• Acacia nilotica in West African plants – A Photo Guide.