Examining range disjunctions in Australian Terminalia (Combretaceae) with taxonomic revision of the T. canescens and T. cunninghamii species complexes

Abstract

Several range disjunctions have been identified in the Australian species of the genus Terminalia L. Field studies and examination of herbarium specimens of taxa with range disjunctions have demonstrated that taxonomic changes are justified. Detailed morphological studies of the Terminalia canescens (DC.) Radlk. species complex showed that four taxa should be recognised. The name Terminalia circumalata F.Muell. is resurrected as a taxon endemic to the Pilbara region, with T. canescens not occurring in that region. The distinction of Terminalia bursarina F.Muell., T. canescens and T. pterocarya F.Muell. is also supported. Terminalia cunninghamii C.A.Gardner has been considered to have a disjunct range between the far north and south-west of the Kimberley region of Western Australia. Terminalia kumpaja R.L.Barrett is described as a new species to accommodate the disjunct southern populations because morphological examination has shown them to be distinct. Terminalia kumpaja is restricted to the Dampier Botanical District. Full descriptions and illustrations of key identifying features are provided for these species. Keys to all Australian Terminalia species are presented. Additional species with disjunct distributions that warrant further study are noted. Lectotypes are selected for Terminalia circumalata and T. rogersii W.Fitzg.