A portrait of Joseph Hooker. One of the portraits on the wall behind him looks rather like Charles Darwin, with his large beard. © RBG Kew

The Royal Botanic Gardens, Kew, has acquired a collection of 19th century letters between some of the greatest botanists of the time, giving an insight into their professional thoughts and personal lives.

The collection, containing 272 letters covering more than 1000 pages, is mainly correspondence between Sir Joseph Hooker – considered the first director of Kew – and leading Amercian botanist of the day, Dr Asa Gray. The handwritten papers date back to the 1850s, and discuss the work of their close friend, Charles Darwin, before and after the publication of On the Origin of Species, as well as giving a glimpse of their own family lives. There is also a lithographed portrait of Hooker, dated 1908.

“This is the most important set of original documents that Kew has purchased for many years,” commented Christopher Mills, Head of Library, Art and Archives at Kew.

“We already hold a large number of important letters to and from Hooker,” he continued, “but these are particularly significant in that we have the corresponding letters between these two important 19th century botanists. Here they are discussing the important new ideas of the day, and also the day-to-day issues affecting their family, giving us an insight into the private individuals which one does not often get.”

Hooker followed in the footsteps of his father, who was also a director of Kew. Joseph also struck out on his own, though, being the first European to collect plants in the Himalayas, for example (in the 1840s), and gaining notoriety when he was imprisoned in the kingdom of Sikkim, along with East India Company representative Dr Archibald Campbell, in a diplomatic tussle.

He helped Darwin to classify plants he had collected in the Galapagos – the trip that inspired the theory of evolution. A lifelong friendship developed from the collaboration.

Gray, whose taxonomy manual of North American plants remains a standard text, was an early and influential supporter of Darwin. Gray published a book of essays arguing for the conciliation of Darwinian evolution and Christian principles.

Joseph Hooker wrote extensively on rhododendrons, seen here on the left in bloom at Kew. © RGB Kew

Hooker and Gray shared a long professional friendship, and the letters mention many of their scientific ideas.

For example, Hooker wrote to Gray: “I am determined to start in my investigations on a different principle & to try to square all my facts with (or arrange them by) the most modern doctrines, without therefore adhering to or accepting those doctrines. The old theory of absolute creations, of single individuals or pairs is used up! Quash them & what’s the use of arguing any more.”

There are also 33 letters from Hooker to his second wife, Hyacinth, written while he was on travels (he visited Palestine and Morocco as well as the Indian subcontinent, for lengthy periods).

“…I miss you awfully,” he says in one, “I do not like this going about without you at all…”

Some of these letters extend up to 16 pages, documenting the people he encountered and places he saw, and his laments when faced with difficulties.

“My own plans are quite unsettled,” he writes at another time, “& I sometimes think seriously of giving up Kew & living in London & writing for the Press. The fact is that I have another baby expected & really can hardly support myself on this book [Flora Indica]: nay, which occupies all my time & entails very heavy expenses. Living here is most expensive.”

Other letters in the collection, which is in two volumes, include correspondence from botanist George Bentham (nephew of philosopher Jeremy Bentham) and Lord Lindley to Lady Hooker, and 75 letters from Jane Gray, Dr Asa Gray’s wife, to Joseph and his wife, written after her husband’s death.

The letters were purchased from a London book dealers, Maggs Brothers, who offered the set to Kew first because of the subject matter. The purchase was supported by the Friends of the National Libraries, the Andrew W Mellon Foundation and an anonymous donor.