According to several authors in the internet the acacias until now included the Australian wattles and the thorn trees of the Serengeti or Namibia - both highly recognisable and iconic groups of plants. Research has shown that the genus Acacia should be split into several genera, and a difficult decision was required as to whether the name Acacia should be used either for a very large group of species found mainly in Australia or for a smaller group found mainly in Africa and Central and South America. Under the internationally accepted rules governing the naming of plants, the International Code of Botanical Nomenclature, the name would normally have remained with the African-American group, as this includes the species Acacia nilotica, which is the type species - that is the African species after which the genus was originally named about 200 years ago.