Sir Joseph Dalton Hooker OM GCSI CB MD FRS (30 June 1817 – 10 December 1911) was a British botanist and explorer of the 19th century. Hooker was one of the founders of geographical botany, and Charles Darwin's closest friend. He was Director of the Royal Botanical Gardens, Kew, for twenty years, in succession to his father, William Jackson Hooker, and was awarded the highest honours of British science.