Monday, 12 September 2011

Plants of the Rugby World Cup 1.—the wattle.

Golden wattle, Acacia pycnantha (Wikipedia commons)
The green and gold of Australia’s sporting uniforms symbolise the wattle, national floral emblem and the biggest plant genus in Australia—a real aussie icon.  In springtime the air is scented with their blossoms.
Wattle is the common name of the genus, immortalised in the Monty Python Bruce sketch: “This here’s the wattle, the emblem of our land.  You can stick it in a bottle, you can hold it in your hand.”  The tree is known to Australians simply as wattle, but it’s the scientific name, Acacia, that has been controversial lately.  The moral of the story that follows (and this is a very brief and rather superficial account) is that the names we use for plants may be important, but the plants stay the same when the names change.  A sub-plot is that people have strong emotional attachments to names and can become quite irrational in their efforts to protect familiar names from change.
The International Code of Botanical Nomenclature (ICBN) is the rule book for applying scientific names to plants.  One of its founding principles is the type principle.  Type specimens are the reference samples for the application of names.  If you and I disagree over an identification of a sample, we can consult the type specimens and see which one our sample matches.  Or if I decide a species name includes not one but two species, the one that includes the type specimen must keep the original name, while the other gets a new name, itself defined by a new type specimen. 
When Veronica linifolia (as Parahebe) was divided, the type specimen determined that the original name stayed with the northern species (left), while the southern one got a new name (now V. colostylis)
This rule is a simple way to make a decision that all can agree with.  It saves arguments, and especially prevents authority figures, commercial or political interests, or overwhelming numbers from dominating the results.  Sometimes though, the results are inconvenient.  
The same thing applies at genus rank, so when the genus Acacia was first described, the African species A. nilotica was deemed to be the type.  Over the years, more than a thousand species had been added to Acacia, including about a thousand from Australia alone.  Then, in the 1980s, botanists started to realise that this huge genus wasn’t a natural group of related species, and it became clear the Australian species weren’t closely enough related to the African A. nilotica group to be allowed to remain in the same genus.  Under the ICBN, the African group should retain the name Acacia, while the oldest genus name that could be applied to the Australian group was Racosperma.  
However, by the late 1980s, a group of botanists concerned more with stability of names than with the principle of objective decision-making had brought a significant change to the International Code, by a vote at the Berlin International Botanical Congress.  From 1986 it has been possible to apply to an international committee to conserve a name with a new type.  This meant that there was a chance to overturn the system and keep the popular or established usage of a name that would otherwise change, by over-riding the strict application of the type principle.
Australian botanists, or at least some of them, took advantage of this and, in Vienna at the International Botanical Congress in 2005, they won the conservation of Acacia with a new, Australian, type species.  The congress was deluged with lobbying emails and faxes in support, from Australian politicians, growers, sports-people and the like.  On the other side, some accused the Australians of racism for trying to force a name change on African botanists.  One Australian email struck me for its sheer illogicality.  This asserted that the name Acacia should stay with the Australian species because Aussie sports teams compete in green and gold symbolising the wattle, as if the change of scientific name somehow meant they’d have to start wearing all black.  
As a result of the Vienna Congress’s decision, the Africans have had to change the names they use instead, and Acacia now applies to the Australian plant group.  That decision was controversial for various reasons and it came up again at the recent Congress in Melbourne, where it was approved yet again.  This was definitely a win for Australia, in accordance with the ICBN.  We botanists must follow it, whether we like it or not (and for the record, I don't).
Really though, the wattles will still smell as sweet whatever their name, and the Aussies will still be New Zealand's great rivals on the rugby field, whether they turn out in green & gold, all black, or pink.

No comments:

Post a Comment