Joseph Dalton Hooker, botanist and traveller, was the son of the eminent English botanist Sir William J. Hooker. He was educated at Glasgow University, qualifying as Doctor of Medicine (MD) in 1839, but his passion was botanical research. That same year he accepted a post as assistant surgeon and naturalist on the ship Erebus which, with the Terror, comprised the famous Antarctic expedition led by Sir James Clark Ross during 1839-1843. The expedition visited the Cape from 17 March to 6 April 1840, during which time Hooker collected about 300 plants. On the return journey he stayed at the Cape again for a few weeks during April 1843, but the hot and dusty weather kept him mainly indoors. He visited Baron C.F.H. Ludwig* and his garden on both occasions. The botanical results of the expedition were published under his name in six volumes between 1844 and 1860.
Hooker later contributed in various ways to the development of South African botany. For example, in 1866 he encouraged P. MacOwan* in founding the South African Botanical Exchange Society, and became its patron; he edited the second edition of W.H. Harvey's* book The genera of South African plants (1968); and many of the numerous plant species that he described and named between 1859 and 1903 came from southern Africa. He received plant seeds from, among others, Henry Hutton* in 1867.
Hooker was elected a fellow of the Linnean Society in 1842, and of the Royal Society of London in 1847, serving as president of the latter society from 1873 to 1878. In 1845 he was appointed botanist to the Geological Survey of Great Britain. Ten years later he became Assistant Director of the Royal Botanic Gardens at Kew, and in 1865 succeeded his father as Director, a post which he held until his retirement in 1885. During 1848 and 1849 he explored Sikkim (in north-eastern India), parts of eastern Nepal and the mountain passes into Tibet, making observations on the geology and meteorology of the region. During the next two years he travelled in east Bengal (now Bangladesh), collecting some 700 plant species. These journeys were described in his Himalaya Journals (1854). In 1860 he travelled to Syria and Palestine; in 1871 he explored the Atlas Mountains in Morocco with the Irish scientist and politician John Ball; and in 1877 visited the Rocky Mountains of Colorado and Utah in the United States.
Hooker supported Charles Darwin's* research on the origin of species and in his "Introductory essay on the flora of Tasmania" (1860) adopted the views of Darwin and Wallace on the derivative and mutable nature of species. His work greatly advanced knowledge of the geographic distribution of plant species. His numerous publications included books on the flora of New Zealand (1867) and the British Isles (1870), the seven volume Flora of British India (1883-1897) and, as co-author to G. Bentham, the monumental three volume Genera Plantarum (1862-1883).
The specimens he collected are housed at Kew and in many other herbaria. He is commemorated in the names of the genus Hookerella and many species. Honours were bestowed upon him by many scientific societies and universities, and he was honoured as a Companion of the Order of the Bath (CB, 1869), Knight Commander of the Order of the Star of India (KCSI, 1877) and Grand Commander of the same order (GCSI, 1897), and received the Order of Merit (OM) in 1907.