Darwin’s Botanists: Joseph Dalton Hooker

Illustration of Rhododendron glaucum from Joseph Hooker’s The Rhododendrons of Sikkim-Himalaya, Biodiversity Heritage Library.

Joseph Dalton Hooker (1817-1911) was born into the botanical world.  His father was William Jackson Hooker (1785-1865), a botany professor at the University of Glasgow who then became director of the Royal Botanic Gardens, Kew.  Joseph eventually succeeded his father in that post, but his career had more bumps than this succession might suggest.  The Hookers did not have the wealth of the Darwins, so they needed salaried appointments in order to pursue their interest in science, something Charles Darwin never had to consider.  William could provide for his family, but as an adult, Joseph had to find his own means of support after graduating with a medical degree from the University of Glasgow.  Eight years younger than Darwin, Joseph Hooker took a similar route to gain experience in natural history by participating in the British Navy’s Ross Expedition to Antarctica, serving as assistant surgeon; both he and the surgeon were also charged with collecting natural history materials.  Setting out in 1839, they visited South Africa and several groups of islands on their way to and from Antarctica, as well as Australia, New Zealand, and Tierra del Fuego. 

By the time Hooker arrived back in Britain four years later, he had not only amassed a large herbarium but also made many drawings.  Like his father he was an accomplished botanical artist and created many of his own illustrations, especially for his early publications.  On his return to Britain, he began work on studying his collection and publishing descriptions of new species.  Hooker also analyzed some of Darwin’s specimens from the Beagle expedition.  Eventually Hooker described many of them and in the process became quite friendly with Darwin who was thrilled to have his plant collection studied after the long delay in John Henslow’s hands (see last post).  Their friendship flourished and continued until Darwin’s death.

In 1841 William Hooker became director of Royal Botanic Gardens, Kew, but there was no paid position available to his son.  Joseph applied to be professor of botany at Edinburgh, but didn’t get the job, so he worked for the British Geological Survey and learned paleobotany.  In 1847, he went on another expedition, this time to the Himalayas as a plant collector financed by Kew.  He sketched many of the plants, especially the rhododendrons, and it is amazing how beautiful these sketches are considering the rough conditions under which he worked (see above).  When Joseph returned to Britain he went to work on his collections, and finally obtained a paid position at Kew as his father’s assistant in 1855.  Ten years later, when his father died, he became director and was paid to cede the elder Hooker’s herbarium to Kew where he could still have access to it. 

In the meantime, Darwin had been developing his ideas on evolution, having written up a 230 page “summary” in 1844.  He had copies made and gave them, in sealed envelopes, to his wife Emma and to Joseph Hooker so that in case of his death it could be published, though he wasn’t ready to do the deed himself.  At one point after this, Hooker bluntly suggested that while Darwin’s interests were definitely broad, extending from variation in domesticated animals to fossils to plant breeding, he really hadn’t delved deeply into any one group of organisms.  He needed to study some segment of the living world so closely that he would get a sense of the issues involved in distinguishing one species from another.  This was the start of Darwin’s eight-year odyssey studying barnacles that resulted in a two-volume publication on them.  Janet Browne (1995) sees this as Hooker’s most significant contribution to Darwin’s thinking. 

Hooker was also very involved in dealing with the crisis that overwhelmed Darwin when he received a letter from Alfred Russel Wallace in 1858 outlining a theory of natural selection very similar to Darwin’s own.  Hooker and the geologist Charles Lyell calmed Darwin down and devised a plan in which they presented Wallace’s paper, along with a short summary of Darwin’s work, at a meeting of the Linnean Society of London (Browne, 2002).  This was another major event in Hooker’s relationship with Darwin and led to Darwin’s writing On the Origin of Species (1859) within a year.  Though they didn’t always agree on all the finer points of the theory, Hooker remained an important support to Darwin especially because in the years after publication of The Origin, Darwin wrote a number of major works on plants.  Hooker supplied not only advice and taxonomic assistance, but also sent Darwin orchids and other plants from Kew. 

Hooker had an illustrious career in his own right as described in Ray Desmond’s biography (1999).  In Imperial Botany, John Endersby (2008) takes a different tack toward Hooker’s profession and analyzes how he used his position at Kew to command an army of collectors around the world to add to the already outstanding herbarium his father had amassed.  Endersby argues that Hooker was intent on remaining in control of plant taxonomy, particularly of naming new species.  He sternly directed collectors to send the material to Kew rather than attempt to describe species themselves.  Such tight reins were difficult to maintain as collectors became more knowledgeable about the plants where they lived and collected, for example, in Australia and India.  Hooker’s argument was that they lacked the broad collection he had available and so tended to see something as a new species, when it was only a variant (Boulter, 2009).  In other words, colonial botanists were splitters and imperial botanists like Hooker were lumpers.  During his career, Hooker published an impressive array of books including Genera Plantarumwith George Bentham, The Rhododendrons of Sikkim-Himalaya, and Flora of British India, as well as works on plants he collected in Tasmania, New Zealand, and Antarctica. 

References

Boulter, M. (2009). Darwin’s Garden: Down House and the Origin of Species. Berkeley, CA: Counterpoint.

Browne, J. (1995). Charles Darwin: Voyaging. Princeton, NJ: Princeton University Press.

Browne, J. (2002). Charles Darwin: The power of place. Princeton, NJ: Princeton University Press.

Desmond, R. (1999). Sir Joseph Dalton Hooker: Traveller and Plant Collector. Kew, UK: Royal Botanic Gardens, Kew.

Endersby, J. (2008). Imperial Nature: Joseph Hooker and the Practices of Victorian Science. Chicago: University of Chicago Press.

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