Format: ORAL

Harvey K. Orel1, Todd G. B. McLay2, Paul I. Forster3, Michael J. Bayly1

1 School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia 2 National Biodiversity DNA Library, NCMI, CSIRO, Parkville, Australia 3 Queensland Herbarium, Department of Science, Information Technology and Innovation, Brisbane Botanic Gardens, Toowong, Queensland, Australia

Taxonomists have relied heavily on floral characters to group taxa and assess relationships, despite the adaptive significance of these characters and their correlation with pollination modes. Even if the taxonomist, wary of misinterpreting homology, chooses to account for the instability of floral characters, there may not be sufficient morphological characters outside of these to make useful inferences. This is especially problematic in groups with numerous instances of separate floral specialisation, where interpreting which characters are symplesiomorphic is difficult. The Eriostemon group (Sapindales: Rutaceae) includes 16 genera and ~209 species that almost all occur naturally in Australia (with ~12 spp. in 3 genera outside of Australia). The group is most diverse in the south-east and south-west of Australia where species most commonly occur in eucalypt-dominated woodlands and forests, but are also found in rainforests, savanna, coastal and montane heathlands, semi-arid scrub and desert shrubland. Morphologically, members of the group vary in habit, leaf phyllotaxy, fruit type and, most notably, floral characters. Pollination syndromes vary between and within genera, with a predominant contrast between flowers that are borne upright with spreading, open petals and flowers that are pendent and tubular or aggregated into inflorescences surrounded by large or colourful bracts. This diversity has resulted in taxonomic legacy of large genera with unspecialised, open petalled flowers, and small or monotypic genera with more complex flowers. I will present results from a phylogenomic study of the Eriostemon group based on target capture sequencing using the Angiosperms353 kit. Our results reveal the extent to which the genus Philotheca (54 spp.) is polyphyletic and highlight how the current classification of that genus is based on symplesiomorphic floral characters. They provide new insight into shifts in pollination modes across the group and support the recognition of two new genera, separated from Philotheca.