Botanical battle over acacia moves to Melbourne

Just before the 18th International Botanic Congress in Melbourne next month, a hundred or so plant namers will gather together to accept decisions made six years ago in Vienna. These are decisons about how we name plants and resolutions for a few thorny disputes in botanical nomenclature.

It all centres around the International Code of Botanical Nomenclature, a surprisingly robust system of rules and precedents that guide scientists when they have to name a newly discovered plant.

But this time something shocking may happen. For the first time since 1905, one of the decisions made in Vienna may be rejected by the plant namers. That decision was to change the plant specimen on which the genus name Acacia was attached meaning that if Acacia is split into a few different genera, which we all support from a scientific perspective, most Australian wattles remain Acacia but African acacias, in particular, require new names.

Broadly speaking this made Australians happy because their 900 or so different wattles didn't have to get new names. It made Africans unhappy because their 150 or so acacias get one of two new genus names - Senegalia or Vachellia. Before the decision it would have been the Australians that were unhappy because the name Acacia was 'attached' to a specimen from Africa and this meant Africans kept this iconic name.

The decision was made in the cause of plant name stability and so that less people who use plant names had their lives disrupted.

All very well but it turns out there was a procedural matter in Vienna that might have made the decision invalid. To rectify this the matter is likely to get yet more attention in Melbourne.

I'm not going to go into all the gory details, but there are two big decisions to make. Firstly whether to accept all the decisions from Vienna, including the Acacia one. If yes, the life moves on and the same people remain happy and unhappy but at least there should be procedural fairness...

If the Vienna decisions are rejected, or perhaps just the one about Acacia, there is a second decision to make. Will the plant naming community accept a compromise? Three are on offer so far but more may be raised from the floor.

The first option is to reject the science and put everything back into Acacia. Or more accurately, to agree to not use the names to reflect what we know about the relationships between species previously lumped into Acacia. This goes counter to what most plant namers want to do with names.

The second option is set up a special committee to come up with 'unusual solutions'. This will delay a final decision further and doesn't take advantage of the experts already gathered in Melbourne.

Finally, a set of new names can be created so that everyone suffers equally. This is an interesting and creative solution. It does mean that users of plant names in all countries may be irritated, but one option they have is to continue to use Acacia.

Some 1400 new names will have be created but they can be fast tracked to some degree due to some subtle changes to priority rules for the new names.

There are  few other extreme ideas floating around, such as rejecting the name Acacia entirely. This is a bit like an extreme version of the third option.

Whatever the solution agreed in Melbourne, it does highlight the passion around what we call plants, at least among a few scientists! But behind all this there are important concepts like creating names that carry information, minimising the changes to names when we can, and trying to get the best outcome for as many people as we can. All this gets mixed up with nationalistic pride and inequity in representation at key meetings such as the 18th International Botanical Congress in Melbourne...

As someone today, users will decide if we can't. But will the name they chose be the best one?

Images: a selection of wattles from Australia, all except the last one currently called Acacia.