Aneuraceae (Metzgeriales) and tulasnelloid fungi (Basidiomycota) - a model for early steps in fungal symbiosis

► Tulasnelloid fungi (Basidiomycota) are epi- and endophytes of Riccardia (Aneuraceae). ► Colonising fungi were identified by ultrastructural and molecular markers. ► Aneuraceae and their fungi are potential model organisms for studies in mutualism. ► Genetically identical fungi form different colonisation types in different plants. ► The host plant determines the way of colonisation and not the fungus.