Acacia nicholsonensis (Fabaceae), a new ‘Minni Ritchi’-barked species of Acacia sect. Juliflorae from the Gulf of Carpentaria region of Northern Australia

Acacia nicholsonensis Cuff is described as a new species of Acacia Mill. sect. Juliflorae (Benth.) Maiden & Betche. Acacia nicholsonensis is currently only known from the upper Nicholson River catchment in the far east of the Northern Territory where it is restricted to the levees and banks of major river channels. A key to the ‘Minni Ritchi’-barked Acacia species of the Top End of the Northern Territory and adjacent regions of tropical northern Australia is presented. The conservation status and ecology of the new species are discussed.