Useful Links
UK & Ireland
Mike Sutcliffe's Photo-Library - www.britishlichens.co.uk
Alan Silverside's Lichen Pages - http://www.lichens.lastdragon.org
Lichen Ireland - www.habitas.org.uk/lichenireland
Lichens of Ireland - http://www.lichens.ie
Irish Lichens - www.irishlichens.ie
Lichens of Wales - http://wales-lichens.org.uk
Scottish grey literature http://tinyurl.com/68wdmbl
Wessex Lichen Group - http://wessexlichengroup.org/
Nature in the Yorkshire Dales (including lichens) - http://www.natureinthedales.org.uk/
Fungi of Great Britain and Ireland - http://fungi.myspecies.info/
Europe and Scandinavia
Italian lichen keys - http://dbiodbs.univ.trieste.it/
Lichen Herbarium Photolibrary, University of Oslo -
Lichen Gallery: Leif & Anita Stridvall - http://www.stridvall.se/lichens/gallery/
North America
Lichens of North America - http://www.sharnoffphotos.com/lichens/lichens_home_index.html
Lichen keys for USA - www.huh.harvard.edu/collections/lichens/index.html
Tropical
Tropical lichens - http://www.tropicallichens.net/
Tropical Lichens & other keys worldwide: http://www.bgbm.org/sipman/keys/default.htm ; these keys are free and cover many areas with relevance for BLS based in or traveling to overseas locations.
Worldwide
Checklists of lichens worldwide: www.biologie.uni-hamburg.de/checklists/portalpages/world_l.htm
Checklist of lichenicolous fungi worldwide - http://www.lichenicolous.net/
Lichen Study Courses (non-BLS - see the BLS Events calendar for BLS workshops etc.)
Field Studies Council re lichen courses: www.field-studies-council.org/publications/bycategory/lichens.aspx
Recording & Mapping
National Biodiversity Network / NBN Gateway: www.nbn.org.uk
ISpot - a website aimed at helping anyone identify anything in nature: www.ispot.org.uk
Air Pollution
OPAL - the Open Air Laboratory project: www.opalexplorenature.org/AirSurvey
Journals and Magazines
British Wildlife: www.britishwildlife.com
Related Organisations & Societies
Plantlife - www.plantlife.org uk.
The British Mycological Society: www.britmycolsoc.org.uk
The Society of Biology: www.societyofbiology.org/home
The Linnean Society: www.linnean.org
The British Bryological Society: www.britishbryologicalsociety.org.uk
International Association for Lichenology - http://www.lichenology.org/
Literature
Recent Literature on Lichens - http://nhm2.uio.no/botanisk/lav/RLL/RLL.HTM