Endoraecium digitatum was described on Acacia notabilis from South Australia but has been reported on more than 20 Acacia spp. throughout the Australian and the Pacific regions. Results are presented on the micro-morphology and taxonomy of E. digitatum from different Acacia species and geographic provenience. E. digitatum revealed a highly non-uniform morphology and is considered a species complex comprising at least six morphologically distinct rust fungi. The name E. digitatum could not be applied to any of the distinguished species by a comparison with available type specimens or the original description as types were depleted and the diagnosis not detailed enough. An epitype is therefore proposed to supplement the lectotype of E. digitatum selected here and to allow delimitation of the new species E. parvum, E. violae-faustae and E. walkerianum from Australia, and E. kauaianum from Hawaii. Endoraecium phyllodiorum is shown to be different from E. digitatum and is proposed as a new combination for Uromyces phyllodiorum. Specimens from Hawaii formerly considered to be E. digitatum represent two species, E. kauaianum and another one preliminarily assigned to E. phyllodiorum. The investigated species show differences between and plasticity within their life cycles. E. parvum, E. violae-faustae and E. kauaianum are macrocyclic. In E. walkerianum, only demicyclic specimens were found, while demi- and macrocyclic specimens occurred in E. digitatum. E. phyllodiorum revealed variable combinations of spore states as well and comprised macro-, demi- and microcyclic life cycle variants. Life cycle variants were considered to express specific variability and were not used to create new taxa. The present results indicate that members of the E. digitatum complex in Australia are not narrowly host specific. Keys are presented for the Australian and Hawaiian species. Taxonomical novelties: Endoraecium kauaianum R. Berndt, Endoraecium parvum R. Berndt, Endoraecium phyllodiorum (McAlp.) R. Berndt, Endoraecium violae-faustae R. Berndt and Endoraecium walkerianum R. Bernd