My general research interests are centered on the study of symbiosis using phylogenetics as a framework for developing specific projects. I am interested in phylogenetic studies of lichen-forming and allied fungi and their use as a model system for the study of mycobiont-photobiont symbiotic interactions and coevolution. The main goals of my phylogenetic studies are to resolve relationships among the main basal lineages of Euascomycetes (lichenized and non-lichenized) with high confidence levels, specifically to contribute toward establishing a stable supraordinal classification of the Ascomycota, reconstruct the origin of the lichen symbiosis, and identify all main lineages of ascomycetes derived from lichen ancestors. We are currently testing the hypothesis that lichenicolous fungi (fungi dwelling on or in lichens as parasites, commensals or saprobes) may be one explanation for the high rate of loss of the lichen symbiotic habit, by allowing the transformation of a fungus from a mutualistic to a parasitic state, and acting as a fungal “half-way house” that could facilitate further transitions to different substrates. We are also assessing the evolutionary and ecological roles of mutualistic associations such as lichens and endophytes in the diversification of the fungi.