Systematics of Australian Plectranthus (Lamiaceae; native mints)

Researchers:
Trevor Wilson Paul Forster (Queensland Herbarium), Barry Conn Murray Henwood (The University of Sydney)
Project sponsors:
Australian Biological Resources Study

Project aims

  • Build molecular phylogenies using nucleotide sequence data from chloroplast and nuclear genomes
  • Describe new taxa in Plectranthus and the Prostantheroideae and provide comprehensive taxonomic revisions and identification tools
  • Identify pollination mechanisms and plant-pollinator relationships
  • Characterise variation in vegetative and reproductive morphology and integrate morphological and phylogenetic data to identify evolution of morphological diversity and pollination
  • Genome sequencing and identification of phylogenetically informative molecular marker

Project Summary

Plectranthus is a large genus of typically succulent perennials shared between Australia and the remainder of the oldworld tropics. It is largely considered an African group, however the number of described species in Australia has steadily grown. The core of this project is about documenting Australia’s biodiversity, by focusing research on taxonomy and systematics for Australian Plectranthus to provide keys and other tools to aid with their identification. Field collected material and DNA material are being used to provide valuable museum specimens and the basis of the first phylogeny for the Australian Plectranthus; these collections will also assist with a better understanding of species distribution and provide insight into biogeographical processes in Australia. This will also be the first step necessary to identify and protect threatened Plectranthus, some of which have already been identified as susceptible to urban development and agricultural practices. 

Research Update

Currently, the first phylogeny of Australian Plectranthus (Lamiaceae) is being constructed using Sanger and next generation sequencing technology. Specimens have been procured from several recent field trips in northern Queensland, a hotspot of diversity for this genus. Highly quality vouchers and living specimens were collected from rare specimens found in remote areas such as Kutini-Payamu and Cape Melville national parks. DNA from these specimens will be integrated in the phylogeny of Plectranthus.