Should you be strolling among the tombstones of St Kilda Cemetery, in Melbourne, or St Anne's, Kew, just outside London, later this spring and hear a strange noise, it may be the sound of some of history's finest botanists turning in their graves. These are the burial places, respectively, of Ferdinand Mueller, Victoria's inaugural government botanist, and of Sir William Jackson Hooker, the first official director of the Royal Botanic Gardens at Kew, and his son, Joseph Dalton Hooker, the Gardens' second director.
These three men spent much of the mid-nineteenth century arguing about the role botanists in Australia should take in the enterprise of classifying the world's plants. Mueller argued that Australians should work on Australia's flora; the Hookers that such work could only be done by men in London. British science prevailed, and the Flora Australiensis - the first survey of the continent's flora - was written by George Bentham, the foremost systematist of his time and a man who had never seen an Australian plant in its native habitat.
Given that the idea of classifying Australian plants in Australia caused the Hookers such consternation, their response to the latest antipodean assault could only be churning soil and revolving skeletons. On 8 October, the next in that long and illustrious line of Kew directors will arrive for his first day at work. Steve Hopper, the first non-Briton appointed to the post, will migrate to the director's office from the University of Western Australia - and even he "wondered a little bit" about what his botanical precursors might have thought of the appointment.
"Of course Bentham struggled" with Australian flora, says Hopper, "like all the European and British botanists did in those days. There's a downside to doing the stuff if you can't get out in the field and see what's going on ... but they were different times, weren't they?" He downplays any post-colonial revolution he might embody: "I guess it is a bit of a leap of faith for Kew. But equally, we do live in a global village these days - even in Perth, which is claimed as the world's most physically isolated city."
Whatever disagreements bristled between the Hookers and their colonial counterparts, there have always been solid links between Australia and Kew. Its first quasi-director was Joseph Banks: as a Botany Bay enthusiast and personal adviser to George III when the gardens were in royal hands, he despatched collectors to the ends of the earth, in particular the new colony of New South Wales, to gather as many samples of exotic vegetation as they could find and build Kew's reputation as a repository for international plants. Sir William Hooker continued the links between the two countries, advising committees in the colonies on the establishment of their own gardens, while his son even made a brief visit to Sydney in the 1840s, on his way back from Antarctica. And Bentham, undertaking Flora Australiensis from his office at Kew, was assisted by a grumbling Mueller, in Melbourne. As Charles Darwin told one botanical artist in 1879, of all the places where one might paint the world's vegetation, one needed to visit Australia because the plants were, in Hopper's paraphrase, "most different here". To be told that by Darwin was tantamount to "being given a royal command".
As Hopper sees it, an Australian background gives him a different way of looking at plants in the rest of the world. "The animals, the plant life here are among the most distinctive on earth," he says, "and biogeographers are also recognising that there's a greater degree of similarity in the floras and faunas across the continuous landmasses of the northern hemisphere, compared to the very insular break-up of southern floras. If you're going to understand plant biodiversity, you need to have a perspective on both."
The two hemispheres even have what he calls a "different sociology" of collecting: "So much of the collection phase has been completed in Eurasia, in North America, and people only very occasionally discover something interesting in really remote areas; in the southern hemisphere and the tropics the job [of collecting] is still one of the big science challenges. In south-western Australia, about a third of the flora has been discovered and described only in the last three decades."
Thirty years is a short span in the context of an institution such as Kew, which turns 250 in 2009, and Hopper is looking forward to considering his new gardens in that longer timeframe: "What will the next 250 years be, and how can we make sure there is a next 250 years?" He cites Kew's Millennium Seed Bank as a model for "the well-endowed, leading botanic gardens of the future", with its mission not only to "conserve all the British flora and 10% of the world's flora as seed" but also to "capacity-build, so that local people develop the skills to collect and store seeds" and send them to London. "The message is to work in partnership as much as possible, and not just with Kew. If you look either side of this continent, around the Pacific or the Indian oceans, if you look to the north, too, there's a hell of a lot of plant biodiversity and a lot of nations struggling to care for it. That's part of the opportunity for Australia."
Whatever the future, there's no doubt that the past was part of the attraction of his new job. "The house I'm going to live in is where Hooker and Darwin discussed The Origin of Species," he says - although more bodies might turn in graves when his Australian hardwood furniture arrives.
It's not the only Australian transplant Steve Hopper will be able to enjoy on the other side of the world: driving into Kew for his induction earlier this year, he could smell eucalyptus wafting through the air. And although there aren't many south-west Australian plants growing in that neck of the woods, he was delighted to read recently that someone had got a Eucalyptus caesia not only to grow but also to flower, a bit further out of London. "It's a weeping species, quite rare," he says, "with big red flowers, beautiful cinnamon bark and white wax on its branches, which droop a bit like a willow." There is one already growing at Kew - in the Australian bed that's just been reinstated in the temperate glasshouse - but Hopper has larger plans for E. caesia at the Royal Botanic Gardens. "I think a grove would be marvellous," he says.