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Native mints: sorting out a family



24 May 2012

Flower of the Victorian Christmas tree (Prostanthera lasianthos) visited by a flower beetle (Phylotocus sp.). Photo credit: Trevor Wilson
Flower of the Victorian Christmas tree (Prostanthera lasianthos) visited by a flower beetle (Phylotocus sp.). Photo credit: Trevor Wilson

Native rosemary (Westringia sp.) and the Australian mintbush (Prostanthera sp.) are just some examples of a large Australian plant group (Prostantheroideae) which belongs to the Lamiaceae family. This family includes other well known culinary herbs such as mint (Mentha sp.), rosemary (Rosmarinus sp.), and sage (Salvia sp.). Dr Trevor Wilson, an associate lecturer from the School of Biological Sciences, has recently been awarded an Australian Biological Resources Study (ABRS) research grant to resolve relationships, describe new species, and study the evolution within this group.

The uncertainty about the relationships in the Prostantheroideae group stems from a classification based, for the most part, on floral features. If plants have similar pollinators, distantly related species can evolve similar floral features. This leads to confusion as to whether species with similar flowers are closely related. The current understanding about relationships in this group therefore requires testing. Trevor says, 'Clear delineation of several generic boundaries and species complexes are necessary before the correct taxonomic treatment of the Prostantheroideae can be achieved.' In other words, he needs to test if each genus is a group of closely related species, and, by identifying differences in DNA and morphology, determine how many species there are.

Dr Trevor Wilson at Mt Kaputar National Park, NSW
Dr Trevor Wilson at Mt Kaputar National Park, NSW

Trevor will use state-of-the-art techniques to examine a combination of molecular and morphological data to resolve relationships. He hopes that, 'In addition to documenting and improving our understanding of Australia's floral diversity, this project will describe species of high conservation value as well as make discoveries about the evolution of Australian flora.'

This three-year $90,000 research grant comes from the ABRS as part of the National Taxonomy Research Grant Program. It funds the post-doctoral position and research expenses through a collaborative effort between the School of Biological Sciences at the University of Sydney and the Royal Botanic Gardens & Domain Trust. Trevor will now be able to conduct the first rigorous, comprehensive revision of the Prostantheroideae.