Few would imagine botanical nomenclature to be a hotbed of passion and intrigue, but the vociferous arguments and machinations of botanists regarding the rightful ownership of the Latin genus name Acacia give an extraordinary insight into the tensions that arise when factors such as aesthetic judgement, political clout and nationalist sentiments dominate the process of scientific classification. After much lobbying and procedural wrangling, on July 16, the last day of the 2005 International Botanical Congress in Vienna, botanists approved a decision to allow an exception to the nomenclatural 'principle of priority' for the acacia genus. With increasing demand by botanists to split apart the massive cosmopolitan and paraphyletic genus into several monophyletic genera, the Vienna decision conserved the name acacia for the members of the new genus from Australia. Normal application of the rules of priority would instead have kept the name acacia for a subset of the trees native to the Americas, Africaand Asia. The Vienna decision was unprecedented in the number of species affected and in the amount of public indignation generated across the world. Many professional and amateur botanists, horticulturalists and naturalists, particularly those working in Africa, Asia and Central America (Luckow et al. 2005), were incensed by the decision. In eastern and southern Africa, where the iconic acacias dominate the savannah landscape, popular newspapers such as Nairobi's Sunday Nation announced in a headline "Did you know it is illegal to call this tree acacia? Australia claims exclusive rights to the name" (Githahu 2006).
This essay argues that the ongoing debate and controversy over the acacia genus name is a reflection of a deeper crisis in botanical taxonomy and nomenclature arising from the use of molecular systematics in classification. The splitting of genera and the shifting of species from one genus to another have not only revived older debates in botany regarding classification systems, but also put a great deal of pressure on genus names themselves. We show how the acacia name debate reveals these tensions and contradictions arising from molecular systematics and how rhetoric centred on a variety of non-scientific and non-rational factors, such as aesthetic judgment, sentiments of belonging, territorial chauvinism and politics (lobbying, vote-rigging, etc), came to dominate the procedures of botanical nomenclature.
In the following sections, we offer a brief review of the history of the science and practice of botanical nomenclature, and show how there have been longstanding tensions between folk- or place-based classification systems and universal, scientific approaches to plant classification. After explaining the relevant conventions and rules set out by the International Code of Botanical Nomenclature, we describe how the controversy over the ownership of the genus name acacia has developed over the past two decades. We draw on arguments published in scientific journals and the popular media, on interviews with botanists and participant observation of the nomenclature sessions during the 2011 Melbourne IBC to show how sentiments, chauvinisms and egos have dominated the debate and prevented any 'scientific' resolution or compromise emerging from within the conventions of international botanical nomenclature. The essay concludes by arguing that the acacia name controversy and other potential naming crises emerging from molecular systematics can only be resolved by recognising and incorporating the social histories of attachment in plant names in processes of botanical nomenclature.