Adaptations to terrestrial habitats displayed by some homobasidiomycetes include rootlike rhizomorphs that allow the fungi to forage along the forest floor, drought-resistant sclerotia, and tough, perennial fruiting bodies.
Aquatic homobasidiomycetes include four species that have retained ballistospory and seven species that have lost ballistospory.
To resolve the relationships among terrestrial and aquatic homobasidiomycetes, we assembled a data set that includes 4 marine species, 1 freshwater species, and 40 diverse terrestrial species (Fig.
All of the aquatic species in our data set are nested in a strongly supported group (parsimony bootstrap = 90%(ML bootstrap = 99%) called the euagarics clade, which has been estimated to contain roughly 7400 species (57%) of homobasidiomycetes (Fig.
Consistent with this prediction, our results suggest that the terrestrial cyphelloid genera Henningsomyces and Cyphellopsis are closely related to marine homobasidiomycetes (Fig.