Phylogenetic position and revised classification of A cacia s.l. ( F abaceae: M imosoideae) in A frica, including new combinations in V achellia and S enegalia

Previous phylogenetic studies have indicated that A cacia   M iller s.l. is polyphyletic and in need of reclassification. A proposal to conserve the name A cacia for the larger A ustralian contingent of the genus (formerly subgenus P hyllodineae ) resulted in the retypification of the genus with the A ustralian A . penninervis. However, A cacia s.l. comprises at least four additional distinct clades or genera, some still requiring formal taxonomic transfer of species. These include V achellia (formerly subgenus A cacia ), S enegalia (formerly subgenus A culeiferum ), A caciella (formerly subgenus A culeiferum section F ilicinae ) and M ariosousa (formerly the A . coulteri group). In light of this fragmentation of A cacia s.l. , there is a need to assess relationships of the non‐ A ustralian taxa. A molecular phylogenetic study of A cacia s.l and close relatives occurring in A frica was conducted using sequence data from matK/trnK , trnL‐trnF and psbA‐trnH with the aim of determining the placement of the A frican species in the new generic system. The results reinforce the inevitability of recognizing segregate genera for A cacia s.l. and new combinations for the A frican species in S enegalia and V achellia are formalized. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society , 2013, 172 , 500–523.