Rarity, taxonomy and genetics: the chequered history of Grevillea williamsonii (Proteaceae)

Resolving uncertainty surrounding the taxonomic and conservation status of rare plants is of utmost importance to enable effective allocation of the limited resources available for conserving biodiversity. Prioritising threatened taxa that are more appropriately regarded as synonymous with more common species represents a waste of resources. Such a scenario may apply to the Australian entity Grevillea williamsonii and consequently its taxonomic status was investigated using chloroplast DNA sequences and nuclear microsatellite data. Haplotype network and genetic structure analyses showed that G. williamsonii was not genetically distinct from, and should be synonymised with, the variable and morphologically similar but more common G. aquifolium. This study highlights the benefit of undertaking genetic analyses where questionable taxonomic status biases conservation prioritisation and management decisions.