Botanist. Worked chiefly on taxonomy and plant geography. Son of William Jackson Hooker. Friend and confidant of CD. Accompanied James Clark Ross on his Antarctic expedition, 1839–43, and published the botanical results of the voyage. Appointed palaeobotanist to the Geological Survey of Great Britain, 1846. Travelled in the Himalayas, 1847–9. Assistant director, Royal Botanic Gardens, Kew, 1855–65; director, 1865–85. Knighted, 1877. FRS 1847.
Sources: DSB ODNB. (See the bibliography for full references to sources)
For more about the 1400 letters exchanged by Darwin and Hooker over forty years, see http://www.darwinproject.ac.uk/darwin-hooker-letters