Vachellia

Vachellia is a genus of flowering plants in the legume family, Fabaceae, commonly known as thorn trees or acacias. It belongs to the subfamily Mimosoideae. Its species were considered members of genus Acacia until 2009.[2][3] Vachellia can be distinguished from other acacias by its capitate inflorescences and spinescent stipules.[4] Before discovery of the New World, Europeans in the Mediterranean region were familiar with several species of Vachellia, which they knew as sources of medicine, and had names for them that they inherited from the Greeks and Romans.[5]

The wide-ranging genus occurs in a variety of open, tropical to subtropical habitats, and is locally dominant.[6] In parts of Africa, Vachellia species are shaped progressively by grazing animals of increasing size and height, such as gazelle, gerenuk, and giraffe. The genus in Africa has thus developed thorns in defence against such herbivory.[7]

By 2005, it had become clear that Acacia sensu lato needed to be split into at least five separate genera. The ICN dictated that under these circumstances, the name of Acacia should remain with the original type, which was Acacia nilotica.[1] However, that year the General Committee of the IBC decided that Acacia should be given a new type (Acacia verticillatum) so that the ~920 species of Australian acacias would not need to be renamed Racosperma. This decision was opposed by 54.9% or 247 representatives at its 2005 congress, while 45.1% or 203 votes were cast in favor. However, since a 60% vote was required to override the committee, the decision was carried, and a nom. cons. propositum was listed in Appendix III (p. 286).[8][9] The 2011 congress voted 373 to 172 to uphold the 2005 decision, which means that the name Acacia and a new type follow the majority of the species in Acacia sensu lato, rather than this genus.[10] However, some members of the botanical community remain dissatisfied.[11]