Graeme’s lecture will use the example of a current taxonomic review of Australia's wallaby-grass species to explore the process of deciding where to place boundaries between plant species and how that process has changed since the 1950s.
Wallaby-grasses are widespread, abundant and ecologically important in southern Australia, represented by about 47 currently recognised species in the genera Rytidosperma and Plinthanthesis. Identification is often difficult and some 'species' are unpalatably variable. Most recognised species were described by the time Joyce Vickery completed her review in 1956, based mainly on morphology. In nearly sixty years since, there has been very little progress in resolving the many outstanding issues of how the species should be differentiated, despite large advances in molecular methods and other techniques. Instead, taxonomic work in recent decades has led to frequent, large-scale re-shuffles of recognised species between genera.
In the past two decades, the few cases of lumping or splitting of wallaby-grass species have been on the basis of a researcher's say-so, with little if any empirical evidence. This lecture will compare this acceptance of professional judgement with the presenter's experiences in mathematics, physical sciences and the law. The lecture will then explain how a combination of morphological analysis, greenhouse experiments and computational techniques is providing a sounder, more transparent understanding of wallaby-grasses at the species level. The results will aid identification of species and future application of molecular methods.
Tuesday 7 October
Mueller Hall, National Herbarium of Victoria, cnr Birdwood Avenue and Dallas Brooks Drive
Tel: (03) 9252 2315
Please direct enquiries to Roger Spencer