officially Royal Botanic Gardens, Kew Botanic garden located at Kew, site of a former royal estate in the London borough of Richmond upon Thames. In 1759 Augusta, dowager princess of Wales and mother of George III, laid out a portion of her estate as a botanic garden. It became an eminent scientific institution under the unofficial directorship of Joseph Banks. In 1840 the gardens were donated to the nation. Under Sir William Jackson Hooker (1785-1865), they became the world's leading botanical institution. Today they are home to 50,000 different types of plants, a herbarium of more than 5 million dried specimens, and a library of more than 130,000 volumes. The three museums at Kew are devoted largely to economic plant products and a laboratory of plant genetics and classification