Systematics is the science dedicated to understanding the diversity of the living world. Systematics includes the process of discovering and describing biological diversity, which is usually known as taxonomy. However, systematics extends beyond purely descriptive studies to generate hypotheses that interpret and synthesise information on diversity allowing predictive classifications to be made. Such classifications can be used in the study of biogeography and phylogeography, in order to examine relationships of biogeographic areas and infer histories of those regions.
At Royal Botanic Gardens (RBG) Melbourne we have expertise in the systematics of Southern Hemisphere plants, algae and fungi.
In addition to traditional morphological methods used to study plant diversity, we have a fully equipped molecular laboratory that enables us to use DNA sequences and other genetic markers. Our studies on systematics encompass several iconic Australian plant groups, such as gum trees and wattles.
Myrtaceae – gum trees, bloodwoods and relatives
Myrtaceae (the myrtle family) is a primarily Southern Hemisphere family that forms a conspicuous part of the Australian flora, including the eucalypts (gum trees), tea trees, paperbarks and bottlebrushes.
Our current research involves collaborative projects with staff at the School of Botany, The University of Melbourne, which focus on resolving the evolutionary history and classification of eucalypt groups such as Corymbia (bloodwoods) and Eucalyptus subgenus Eudesmia. The phylogeography of Eucalyptus deglupta, one of the few eucalypt species not native to Australia, is being investigated with collaborators in Indonesia.
Previous molecular systematic studies by Frank Udovicic and collaborators on Melaleuca (paperbarks), Callistemon (bottlebrushes) and related genera in Myrtaceae, showed that the Australian species of Callistemon did together form a natural group. Melaleuca, on the other hand, was a mess, with several evolutionary lineages being more closely related to other genera than each other. This signals the need for further study on the evolutionary history of this group.
Legumes – wattles and peas
Detailed systematic studies of Australia's largest genus of plants, Acacia, are one of the major research interests at Royal Botanic Gardens Melbourne. Molecular Systematist Dan Murphy and collaborators have recently proposed a new informal classification for Acacia (to be published in Taxon).
Other current legume research includes that of Dr Gillian Brown, who is analysing the Pulchelloidea clade within the genus Acacia and investigating the phylogeny of the mimosoid legume tribe Ingeae, as part of an Australian Research Council (ARC) funded Linkage Grant between RBG Melbourne and The University of Melbourne.
Staff at Royal Botanic Gardens Melbourne co-supervise students with Australian universities. James Kidman (Honours, The University of Melbourne) recently analysed the phylogenetic relationships of the non-Australian phyllodinous Acacia species.
Taxonomic and systematics studies of the peas (Fabaceae), particularly in the tribes Brongniartieae (e.g. Templetonia) and Bossiaeeae (e.g. Platylobium), have been a long-term interest of RBG Melbourne staff. Taxonomic research on these groups is currently being undertaken by Ian Thompson, funded by an Australian Biological Resources Study (ABRS) grant.
Proteaceae – proteas, banksias and more
A study is currently being undertaken at RBG Melbourne, in collaboration with Peter Weston (RBG Sydney), on the diverse Australian Proteaceae genus Persoonia, and related genera: Acidonia (south-west Australia), Garnieria (New Caledonia) and Toronia (New Zealand).
The study, funded by the Hermon Slade Foundation, is combining phylogenetic information (molecular, morphological and pollen data), geographic patterns of taxa, and molecular dating to test different historical biogeographic hypotheses.
Poaceae – grasses
Staff at Royal Botanic Gardens Melbourne are undertaking molecular and morphological research on several grass groups. Examples of recent grass projects include:
- A Willis studentship, undertaken by Charlotte Hurry, determined the number of species of Triodia found in Victoria. This study placed Victorian populations within the southern temperate clade, using molecular and morphological data.
- An ongoing study of New Zealand and Australian grasses, is being conducted with New Zealand collaborators Kelvin Lloyd and David Orlovich (University of Otago). Nuclear and chloroplast genes are being used to examine the relationships within and between Australian and New Zealand grass taxa.
- A project currently being undertaken at RBG Melbourne, in collaboration with the Victorian Department of Primary Industries, to develop methods for molecular identification ('DNA barcoding') of grasses. This research focusses on molecular diagnostics of stipoid grasses. These grasses belong to the tribe Stipeae of the family Poaceae, which includes genera such as Nassella,Stipa and Austrostipa. A number of species are highly invasive and a major biosecurity threat to Australia.