 He was elected a Fellow of the Linnean Society of London in 1794 (Natural History Society) commemorating the great Swedish naturalist Carl Linnaeus, whose "Species Plantarum" (1753) became the internationally accepted starting point for all botanical nomenclature (binomial naming of plants by genus and species, based on their sexual reproductive parts) and served as its secretary (1798-1825).He was elected a Fellow of the Royal Society in 1809.Botanist Robert Brown, Macleay's close friend and suitor of his eldest daughter Fanny, a competent botanical artist, named the plant genus Macleaya in his honour.