He is a Co-PI on the NSF-supported, multi-laboratory Assembling the Fungal Tree of Life project, which seeks to reconstruct the major branches of the fungal phylogeny using molecular and morphological data. He has written on morphological and ecological diversification in fungi, focusing on Basidiomycota (mushroom-forming fungi and relatives), and has contributed several pages on Basidiomycota to the Tree of Life Web Project.