An analysis of the African Acacia species: their distribution, possible origins and relationships

Abstract

The three subgenera recognized within the genus Acacia are outlined and the global distribution of each is indicated. The differences between the subgenera and the degree of relationship and levels of specialization are discussed briefly. It is suggested that the ancestral members of the genus were climbers or lianes. Past geological events considered likely to have influenced the distribution of the  Acacia species in Africa are outlined. The number of  species recorded from each African country is tabulated and the distribution and concentration of species within the genus Acacia as a whole and within each subgenus in Africa are illustrated. The highest concentrations of species within each subgenus occur in tropical east and south-east Africa. The distribution o f species within some o f the individual African countries and possible affinities are discussed and attention is drawn to the main centres of endemism. The distribution of the African species is correlated with the major phytogeographical regions recognized on the continent. The relationships between the African and the American, Madagascan, Indian and Australian  Acacia species are discussed briefly.