Pressing ferns in Queensland, Australia, 2019
Credit: R. Edwards
I am broadly interested in plant movement and biogeography, both on the scales of continents and on the scale of mountain ranges.
I'm currently using a clade of cheilanthoid ferns (Pteridaceae) centred in Australia to explore some of these questions. This group of ferns is unique in that its members are adapted to survive in very dry environments—an unusual trait for a fern, which requires water for sperm to swim in for reproduction to occur. Although originating in Australia, some of the species in this clade have managed to colonise nearby islands and even move into southeast Asia. I am keen on understanding the biology driving the biogeography of these ferns: does reproductive mode (sexual vs. asexual) allow for greater dispersal ability? Or is it greater resistance to inbreeding vs. outcrossing? Or might it be ploidy?
I also wish to uncover the effects that their many reproductive strategies have had on diversification. It is thought that these strategies have helped them reproduce despite the scarcity of water. Have these strategies arisen more than once? Which areas have these ferns been able to colonise because of them?
Conveniently, cheilanthoid ferns are also found in the Andes, an area in which I have worked before and which I am passionate about. Previously I studied floral evolution and classification in the Melastomataceae, the eighth largest flowering plant family. I remain interested in melastomes distribution and diversification in the Andes, but those inquiries are on the back burner for now.
I also have an interest in systematic methods, and how genetic data can be used (or misused) when proposing a phylogeny or inferring properties of said phylogeny.
I am excited to uncover the stories plants and genes have to tell us, and I hope you'll join me along for the ride.
- Currently, several of the Cheilanthes from Australia are known as polyploid-only lineages. However, theory says polyploids should arise from diploids. Previous research has been able to locate cryptic diploids within current species circumscriptions. I am reviewing herbarium collections with the aim of identifying the missing diploid populations of two Australian Cheilanthes species.
- Recent work has shown that most ferns are able to successfully undergo the highest level of inbreeding—known as intragametophytic selfing, which results in a completely homozygous offspring. However, not since the experiments of Klekowski in the late 1960s and early 1970s have we compared the relative viability of the forms of reproduction available to ferns. I am performing crosses to determine the relative viability of each strategy. By coupling this information with genetic marker data, we'll be able to understand more closely how ferns actually reproduce in the wild.
- In collaboration with Kathryn Picard and Eric Schuettpelz, I am working on improving the phylogeny for Pteridaceae, and for Australian Cheilanthes more narrowly. I will soon be moving into the sequencing phase, so check back for updates.
- In collaboration with Ben Redelings, I am currently exploring the role that models play in generating alignment hypotheses. Using simulated sequences, we have found that including among-site rate variation during alignment inference improves the alignment's accuracy and recall.