9712484 DePriest Lichens, the fungi that form symbiotic associations with photosynthetic algae or cyanobacteria, are geographically widespread in occurrence, ecologically important, but understudied taxonomically and phylogenetically despite their representing one-fifth or more of known fungal species diversity. This is true in microcosm for the species-rich and highly conspicuous lichens such as Cladina and Cladonia, which carpet wide expanses of northern forests and arctic tundra as well as isolated patches on exposed rocky coasts and tropical sand beaches. These lichens are critical components of their ecosystems, especially in northern latitudes where they provide food for reindeer and caribou. Various groups within the lichen family Cladoniaceae have been the subject of national or regional taxonomic treatments, but the family remains unsynthesized on a worldwide basis. The absence of a robust taxonomic framework limits the further use of Cladonia as a model system for the study of chemical evolution (in "lichen substances"), morphogenesis, and artificial lichenization. These taxonomic and phylogenetic matters are being addressed by a team of lichenologists headed by Dr. Paula DePriest at the Smithsonian Institution, site of one of the world's major collections of lichens, with her colleague Prof. Samuel Hammer of Boston University, along with colleagues at Duke University and elsewhere in the U.S. and in Finland, home to a strong tradition of lichen research. The team will focus on the c. 11 genera and estimated 500 species in the family Cladoniaceae, using existing collections in natural history museums and augmenting these with new field collections. A major emphasis in the research is the acquisition of new sets of characters for taxonomic discrimination and phylogenetic comparison, including molecular DNA sequence data and morphological features of hyphal growth of the fungus, the so-called podetia. The integration of these various kinds of evidence to improve classification and phylogenetic inference constitutes a pioneering model for the modernization of lichen systematics. Products of the team's activities will include traditional publications as well as Web-based outputs.
