Every 6 years, when the International Botanical Congress meets, it tackles a backlog of problems related to the naming of plants. At the Congress in Melbourne, Australia, in July, one longstanding debate finally got closure: who gets the acacia.
To two different continents, the acacia is more than just a tree—it's an icon: the flat-topped thorn trees silhouetted against a red African sky; the golden wattle of Australia, whose green and gold colors inspire the garb of the country's Olympic athletes. For hundreds of years, since Swedish botanist Carl Linnaeus first described the type species of the genus Acacia in Africa in 1773, both continents could lay claim to acacia trees. But in the past 30 years, anatomical and genetic analyses demonstrated that Australian and African acacias do not belong in the same genus at all.
So which trees—Australian or African—should be known as actual Acacia? Africa has prior claim since the first type species, Acacia nilotica, was found there, but Australia has the overwhelming majority of species: more than 1000, compared with Africa's 80. The issue was seemingly resolved at the 2005 botanical congress in Vienna, when the delegates decided that the acacia would belong to Australia. But another 6 years of debate ensued.
The debate drew to a close when delegates to the 2011 botanical congress voted to uphold the 2005 decision. Australia's acacias will retain the genus name, and the new type species will be the Australian Acacia penninervis. African species would be assigned to the genus Vachellia.
“This closes a difficult chapter in international botany,” says Kevin Thiele, a botanist from the Western Australian Herbarium in Kensington. “The vote was very clear and supported by a cross-section of the international community, not just Australians.”
