Robert Brown, the typification of his new Acacia names in edition 2 of Aiton's 'Hortus kewensis'

Robert Brown published nine new species of Acacia in W.T. Aiton’s second edition of "Hortus Kewensis". In the past, typification of these species has presented problems for two main reasons. Firstly, there were uncertainties regarding the material on which they were based, i.e. Brown’s "wild" gatherings from Australia between 1801 and 1805, and/or from plants in cultivation in England. Secondly, it appears that there are no cultivated specimens extant which can be regarded as type material. There is, however, a collection by William McNab, a gardener at Kew, who made specimens of Brown’s Acacia species from cultivated plants at Kew between 1806 and 1809; this collection is curated by the National Herbarium at Dublin (DBN). The following Brown species names are here lectotypified on the basis of Brown’s "wild" material: A. alata, A. biflora, A. marginata (=A. myrtifolia), A. melanoxylon, A. pulchella and A. sulcata; a neotype for A. acicularis (=A. brownii) has been chosen from Brown’s "wild" collections while A. armata is neotypified on a cultivated plant in the William McNab collection at DBN. One species, A. ciliata (= A. browniana var.browniana), had been neotypified in a previous paper.