Botanic Gardens Trust, Sydney, Australia

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Trust scientist researches mint family

Royal Botanic Gardens and Domain Trust scientist Dr Trevor Wilson is making a significant contribution to the global understanding of the mint family (Lamiaceae), while also improving our understanding of the Australian flora. 

There are over 300 species in the mint family (Lamiaceae) that belong to an endemic Australian subfamily (Prostantheroideae). Some of these are well known in horticulture, such as native rosemary (Westringia sp.) and the Australian mintbush (Prostanthera sp.), and others demonstrate spectacular forms that add to the amazing complexity of the Australian bush.

Through a collaborative effort between the Royal Botanic Gardens and Domain Trust (the Trust) and the University of Sydney (USYD), funding from the Australian Biological Resources Study (ABRS) has created a botanist position to conduct the first rigorous, comprehensive revision of the Prostantheroideae. Dr Wilson, a USYD graduate, is the principal investigator of this project, along with co-collaborators Dr Barry Conn (the Trust) and Associate Professor Murray Henwood (USYD).

As well as there being a large number of species already described, there are also at least 50 phrase names in the Prostantheroideae. These are names that describe a population sufficiently different to suggest they are a different species but have not yet been formally named and described. Preliminary data from our molecular studies suggest that those species we think are related because they share common features have not necessarily evolved from one another, but have evolved independently to develop extremely similar adaptations, a process called convergent evolution. Such characters include bird-pollinated flowers or stamens that have complicated levering systems to dispense pollen in a clandestine manner. A correct treatment of this group is required to prepare better identification tools for the recognised taxa, as well as to provide a better foundation for describing new species.

With a prior background in studying evolution and plant morphology, Dr Wilson has gained extensive experience in the Lamiaceae from his PhD on the ecology and molecular systematics of the largest genus in this group, Prostanthera. He will now use the next three years to delineate the generic, sectional and species complexes in this group in addition to describing new species. This work makes the Trust a significant contributor to the global understanding of the Lamiaceae while it improves our understanding of the Australian flora. 

Dr Wilson is currently using molecular and morphological data through state-of-the-art techniques to resolve relationships within the Prostantheroideae. Phylogenetic trees, which describe the relationships between species, using DNA sequence data from nuclear and chloroplast genomes are being used to test our current understanding of the group that have so far only relied on morphology. He will also be re-examining morphology, such as flower shape, to investigate whether quantifiable morphological data supports the current classification; a comprehensive understanding of floral traits will also be mapped onto the inferred evolutionary history of the group and allow us insight into evolutionary trends in pollination within the Australian landscape, for which there is currently little known.

Lachnostachys-Kalbarri

Microcorys_capitata

Trevor-in-Mt-Buffalo

Phylogeny of Prostanthera
Phylogenetic tree for Prostanthera