Ramalina fastigiata with Xanthoria parietina
- Photograph of these two lichens growing together on a branch.
- http://www.clear-mind-photos.com/lichens_-_fruticose_-_on_bark/ramalina_fastigiata_with_xanthoria_parietina_070608_01.htm

Cladonia cristatella
- Article by Tom Volk on the British soldier lichen, where the fungal element is associated with the green alga, Trebouxia erici.
- http://botit.botany.wisc.edu/toms_fungi/jul2002.html

A Lichen in Close-up
- Images of a lichen at three different magnifications, the most detailed showing the algal and fungal components.
- http://www.microscopy-uk.org.uk/mag/artoct03/arfungi.html

Life on the Rocks
- A peep into the world of lichens by Paul James with photographs of a number of species growing in Wales.
- http://www.microscopy-uk.org.uk/mag/artjun02/pjlichens.html

Lichens
- Photographs of several species of lichen growing in their natural habitat in Hawaii.
- http://jupiternielsenflameworking.com/hawaiianflora/lichen.html

MarLIN Image Gallery
- Photographs of a number of species of lichen often found growing close to the sea.
- http://www.marlin.ac.uk/gallery/index.php?spgmGal=Species/Ascomycota

Caloplaca coralloides
- Research project by Megan Kelso provides photographs and plenty of information on this lichen which can be found living on rocks close to the sea.
- http://www.mbari.org/staff/conn/botany/lichens/index.htm

Common Orange Lichen: Xanthoria parietina
- Photograph and information on this species and a map showing its distribution round the coasts of Britain.
- http://www.marlin.ac.uk/species/Xanthoriaparietina.htm

Tar Lichen: Verrucaria maura
- Photograph and information on this maritime species with a map showing its distribution round the coasts of Britain.
- http://www.marlin.ac.uk/species/Verrucariamaura.htm

Sea Ivory: Ramalina siliquosa
- Photograph and information on this maritime species and a map showing its distribution in Britain.
- http://www.marlin.ac.uk/species/Ramalinasiliquosa.htm

Black Lichen: Lichina pygmaea
- Photograph and information on this maritime species and a map showing its distribution in Britain.
- http://www.marlin.ac.uk/species/Lichinapygmaea.htm

Verrucaria mucosa
- Photograph and information on this maritime species and a map showing its distribution in Britain.
- http://www.marlin.ac.uk/species/Verrucariamucosa.htm

Black Shields: Tephromela atra
- Photograph and information on this species with a map showing its distribution in Britain.
- http://www.marlin.ac.uk/species/Tephromelaatra.htm

Parelle: Ochrolechia parella
- Photograph and information on this maritime species with a map showing its distribution in Britain.
- http://www.marlin.ac.uk/species/Ochrolechiaparella.htm

Orange Sea Lichen: Caloplaca marina
- Photograph and information on this maritime species with a map showing its distribution in Britain.
- http://www.marlin.ac.uk/species/Caloplacamarina.htm

Catalog of California Lichens
- 1575 species have been identified from this state, the great geographic diversity being responsible for the relatively large number of lichens found.
- http://ucjeps.berkeley.edu/constancea/84/index.html

Identifying North American Lichens: A Guide to the Literature
- Provides general lichen references including works for beginners, lichen keys online, and a lichen bibliography by genus.
- http://www.huh.harvard.edu/collections/lichens/guide/index.html

FIA Lichen Indicator
- The Forest Inventory and Analysis service in the United States monitors the lichen community in order to assess the impact of air pollution on forest health.
- http://www.fia.fs.fed.us/program-features/indicators/lichen/

Lichenland
- Offers ways to find out more about lichens including Lichenlite, an introduction for children. For more advanced study there is a synoptic key and a comprehensive identification aid.
- http://ocid.nacse.org/lichenland/

Lichens as Bioindicators of Air Pollution
- Technical article discussing how lichens play prominent roles in air pollution studies because of their sensitivity to different gaseous pollutants, particularly sulfur dioxide.
- http://www.colostate.edu/Depts/Entomology/courses/en570/papers_1996/simonson.html

The World of Lichenology
- Information on the International Association of Lichenologists, photographs of various lichens and links to other lichen-related websites.
- http://www.botany.hawaii.edu/cpsu/lichen1.html

Lichen Images
- Provides photographs of about 50 species.
- http://www.wildaboutbritain.co.uk/gallery/browseimages.php?c=76&userid=

Cryptothecia rubrocincta, the Christmas Lichen
- Photographs and article by Tom Volk on this spectacular lichen which can be found in the tropical regions of the Americas.
- http://botit.botany.wisc.edu/toms_fungi/dec2006.html

Lichens of North America
- Details of the comprehensive book of this name, and an interesting introduction to the biology of lichens and their relationships with man and the environment.
- http://www.lichen.com/

LIAS
- Provides a global information system for lichenized and non-lichenized ascomycetes.
- http://www.lias.net/

Lichen Determination Keys Available on the Internet
- Provides links to keys providing details of the lichens that can be found in many countries throughout the world.
- http://www.bgbm.fu-berlin.de/sipman/keys/

Walton Hall Nature Trail
- Take a walk through the churchyard to see what lichens grow on the different man-made outcrops of stone.
- http://www.open.ac.uk/Nature_Trail/Lichen.htm

Peltigera aphthosa: Green Dog Lichen
- Photograph and description of this species and information on its range and habitat, its fire risks, associates and reproduction.
- http://www.rook.org/earl/bwca/nature/moss/peltigera.html

Island Moss: Cetraria islandica
- A description of this species beloved of caribou in winter, and information on its habitat, associates, uses and reproduction.
- http://www.rook.org/earl/bwca/nature/moss/cetraria.html

Growth and Development in Lichens
- Each species of lichen has its own preferred substrate. This article describes how and where they grow and the extremes of climate that they can tolerate.
- http://www.earthlife.net/lichens/growth.html

Reproduction and Reproductive Structures
- Outline with diagrams of the two fundamentally different sorts of reproductive bodies possessed by lichens, and the three main types of vegetative reproduction where pieces of lichen detach.
- http://www.earthlife.net/lichens/reproduction.html

Lichen Pictures
- Photographs of Acolium hawaiiense, Acroscyphus sphaerophoroides, Anaptychia leucomelos, Bacidia medialis, Bryoria furcellata, B. smithii, Buellia aeruginascens, B. proximata, B. pruinosa, B. tincta, Caloplaca erythrantha and Teloschistes flavicans.
- http://www.botany.hawaii.edu/cpsu/pictures/0.html

The Earthlife Web Lichen Image Directory
- About 40 images of lichens, including some unidentified ones.
- http://www.earthlife.net/lichens/images/photos/thumbs/thumbs1.html

Lichen Portrait Gallery
- Photographs of over eighty species of lichen from North America.
- http://www.lichen.com/portraits.html

Introduction to Lichens
- A lichen is a combination of two organisms which live together intimately. Information on their fossil record, life history and ecology, systematics and morphology.
- http://www.ucmp.berkeley.edu/fungi/lichens/lichens.html

Letharia vulpina
- Photograph of Wolf Lichen which in the past was put to many uses by the indigenous peoples in North America.
- http://www.lichen.com/bigpix/Lvulpina.html

Checklist of UK Recorded Lichens
- Provides a list of all the species known to be found in the United Kingdom.
- http://www.mapmate.co.uk/checklist/lichens.htm

Lichens: Dual Organisms
- Twenty four photographs ranging from lichen covered rock faces, through individual species to magnified sections, published in a pictorial supplement to the Fifth Kingdom.
- http://www.mycolog.com/chapter7.htm

Plants Profile for Fayodia striatula
- Details of this lichenous member of the family Tricholomataceae.
- http://plants.usda.gov/java/profile?symbol=FAST