Online Keys for Fungi and Lichens

General
Ectomycorrhizae: DEEMY: Identification (dynamic) Ludwig-Maximilians-Universität München – Systematische Mykologie
Fungal Identification Keys European Mycological Association
Illustrated Keys to Epiphytic Lichens of Various Parts of Italy (dynamic) KeytoNature - Dryades
Lichen Key Archive (listing) University of Oslo, Botanical Museum
Macrofungi of Costa Rica – Keys to Species (dynamic) New York Botanical Garden
Key to Major Groups of Mushrooms Michael Kuo
MycoKey (dynamic) University of Århus, Department of Systematic Botany
Bestimmungsschlüssel verschiedener Pilzarten (link collection) Pilzewelt.de
Acrasiomycota and Myxomycota
Echinosteliales (dynamic) Real Jardín Botánico
Ascomycota
Lichenized and Non-lichenized Ascomycetes: LIAS: Identification (dynamic) Botanische Staatssammlung München
LIAS light – A Database for Rapid Identification of Lichens (dynamic)  
Identification Keys Consortium of North American Lichens
Key to Folicolous Lichens and their Lichenicolous Fungi (static) Universität Bayreuth, Lehrstuhl für Pflanzensystematik
Lichen Determination Keys (static) Freie Universität Berlin, Botanischer Garten und Botanisches Museum Berlin-Dahlem
World Key to the Leparia Species (dynamic) Key to Nature
Key to the Genera of Australian Lichens: Apothecial Crusts (static) Australian Biological Resources Study
Key to the Genera of Crustose Pyrenocarpous Lichens in Australia (static)  
Key to the Genera of Australian Macrolichens (pdf-document)  
Keys to the Lichen Genera of the Neotropics (static) Freie Universität Berlin, Botanischer Garten und Botanisches Museum Berlin-Dahlem
Key to Lichens from Northern Victoria Land (Continental Antarctica) (dynamic) University of Trieste
Keys to the Lichen Genera in the Pacific Northwest, USA (static) LandscapeEcology
Key to Lime-loving (calciphilous) Lichens in eastern North America (static) Eastern Lichen Network
Keys to the Macrolichens of British Columbia (static) British Columbia Ministry of Forests
Keys to Lichens of Minnesota University of Minnesota, Bell Museum & Department of Plant Biology
Illustrated Key to British Lichens on Twigs (dynamic) The Natural History Museum
Key to Podetiate Lichens of Highland Ecuador (static) Freie Universität Berlin, Botanischer Garten und Botanisches Museum Berlin-Dahlem
The epiphytic macrolichens of Estonia (dynamic) Key to Nature - Dryades
Los macrolíquenes epifitos de España (dynamic) KeytoNature - Dryades
Key to Lichens of Italy (dynamic) KeytoNature – Dryades
An Interactive Lichen Key for Iran (dynamic) University of Tabriz, Department of Plant Science
Interactive Lichen Key for the Greater Sonoran Desert (dynamic) Arizona State University, Lichen Herbarium
Epiphytic Macrolichens of Arizona: Key to the common genera and species (static)  
Keys to the Caliciales of Norway (static) Jørn Middelborg
Keys to the Calicioid Lichens and Fungi of the Pacific Northwest of the USA (static) LandscapeEcology
Synoptic Keys to the Inoperculate Stromatic Discomycetes in the Nordic Countries (static) University of Oslo, Department of Biology, Myco Site
PezWeb – a Web Site Dedicated to the Study of the Pezizales: Genus-Finder (dynamic) Northwest Alliance for Computational Science and Engineering
Key to the Cladoniaceae of the Guianas (static) Smithonian Institution, National Museum of National History
Key to the Hypocreales of the Southeastern United States (dynamic) United States Department of Agriculture, Agricultural Research Service
Lasiosphaeriaceae: Keys to Genera (static) The Field Museum, Chicago
Revised Key to Megalosporaceae (static) Freie Universität Berlin, Botanischer Garten und Botanisches Museum Berlin-Dahlem
Determination Key for mollisioid Dermataceae (static) Andreas Gminder
Bestimmungsschlüssel für mollisioide Dermataceae (static)  
Australian Physciaceae (pdf-document) Australian Biological Resources Study
Key to Genera of the Sarcoscyphineae (static) Harvard University Herbaria
Pyrenomycetes from southwestern France – Keys to Xylariaceae (dynamic, static) F. Candoussau, J. Fournier, J.-F. Magni, France
Key to Taxa of Xylariaceae (dynamic) Washington State University
Key to the yellow cetrarioid lichens in the Tibetan area (dynamic) Key to Nature
Key to Morels (static) Michael Kuo
Key to False Morels (static)  
Key to Allocetraria species (dynamic) Key to Nature
Provisional illustrated key to the lichen genus Cladonia (incl. Carassea) in SW Brazil (static) Freie Universität Berlin, Botanischer Garten und Botanisches Museum Berlin-Dahlem
Hypomyces Identification (dynamic) United States Department of Agriculture, Agricultural Research Service
Revised Key to Hypotrachyna in Tropical America (static) Freie Universität Berlin, Botanischer Garten und Botanisches Museum Berlin-Dahlem
Key to the Lepraria and Leprocaulon species in Greenland (dynamic) Key to Nature
Key to Nephromopsis species (dynamic)  
Key to Parmelia of Great Britain and Ireland (static) British Lichen Society
Mason Hale's Key for the Genus Parmotrema Occurring in Tropical America (static) Freie Universität Berlin, Botanischer Garten und Botanisches Museum Berlin-Dahlem
Identification Key to the Genus Pertusaria in Europe and the Mediterranean (static)  
Key to the Foliicolous Species of the Genus Porina (static) Universität Bayreuth, Lehrstuhl für Pflanzensystematik
Revised Worldwide Key for the Genus Relicina (static) Freie Universität Berlin, Botanischer Garten und Botanisches Museum Berlin-Dahlem
Key for the Genus Stereocaulon in Tropical America (static)  
Trichoderma/Hypocrea Identification (dynamic) United States Department of Agriculture, Agricultural Research Service
Key to the Usnea species in the Baltic countries (dynamic) Key to Nature
Key to the Usnea species in Europe (dynamic)  
Keys to Usnea in the Pacific Northwest, USA (static) LandscapeEcology
Keys to Xanthoria in the Pacific Northwest, USA (static)  
Basidiomycota
Key to Common British Basidiomycetes (static) North West Fungus Group
Key to Norwegian Polypores (in Norwegian; traditional) Division of Botany and Plant Physiology, Department of Biology, University of Oslo
Selected Rust Fungi on Fabaceae (Legumes) in or near the United States (dynamic) Systematic Botany & Mycology Laboratory, ARS, USDA
Keys to Species of Amanita (PDF) Rod Tulloss' Pages
Key to North American Armillaria Species (static) Tom Volk's Fungi Home Page
Key to Species of Collybia in the Northeastern United States and Adjacent Canada (static) New York Botanical Garden
Key to Cortinarius Subgenus Dermocybe in the Nordic Countries (static) University of Oslo, Department of Biology, Myco Site
Key to the Taxa of Flammulina (static) University of Tennessee, Mycology Lab
Key to Sections of Gymnopus in the Northeastern United States and Adjacent Canada (static) New York Botanical Garden
Key to Lactarius of North America (dynamic) Michael Kuo
Leccinum and Phylloporus in Costa Rica (dynamic) New York Botanical Garden
Macrofungi of Costa Rica – Interactive Keys to Leccinum & Phylloporus species (dynamic)  
MycoKey (dynamik key to 528 genera of the Basidiomycota and more than 2000 pictures) Thomas Læssøe & Jens H. Petersens (private website)
Ravenelia in the United States and Argentina (dynamic) United States Department of Agriculture, Agricultural Research Service
Key to Species of Rhodocollybia in the Northeastern United States and Adjacent Canada (static) New York Botanical Garden
The Genus Tilletia in the United States (dynamic) United States Department of Agriculture, Agricultural Research Service
Tomentella und verwandte Gattungen (in German) Frank Dämmrich (private website)
Anamorphic Fungi
Trichoderma Identification (dynamic) United States Department of Agriculture, Agricultural Research Service
CBS Yeast Database (dynamic) Centraalbureau voor Schimmelcultures
Yeasts and Yeast-like Organisms (static) University of Wisconsin