Tom Madsen

Dissertation Project

Liverworts, like most land plants, have mycorrhizal associations with a diverse array of fungi. Some liverwort clades, namely Aneuraceae and Scapaniaceae, are characterized by unusally high symbiont specificity, and possess other traits suggesting a partially mycoheterotrophic lifestyle.

My dissertation research focuses on the evolution and ecology of these liverworts and their basidiomycete symbionts. Using a phylogenetic approach, I am investigating patterns of mycorrhizal specifity within Scapania, a predominantly northern-hemisphere genus that specializes on sebacinoid fungal symbionts. I am also using stable isotope analysis to look for evidence of myco-heterotophy among selected taxa within the Aneuraceae and Scapaniaceae.

Other Research Interests

Orchidaceae & Lycopodiaceae

Plants that obligately exploit fungal carbon are generally slow to reproduce, and though the species may be geographically widespread, populations are often local in occurrence. As such, they may be disproportionately impacted by habitat destruction, and the showier taxa (within Orchidaceae & Lycopodiaceae, for example) by illegal collection.

Their dependence on symbiotic fungi has also frequently stymied attempts to propagate these plants for reintroduction efforts. Among such species in North America, fewer are in greater peril than orchids endemic to the tallgrass prairie biome (over 99% of which has been destroyed). I am working to develop improved methods of symbiotic propagation for several of these species, including the federally-Threatened Platanthera leucophaea.

Lunularia cruciata

A rare bloom in the Berkeley Hills