Botany Photo of the Day
In science, beauty. In beauty, science. Daily.

January 18, 2017: Botany Photo of the Day is being actively worked on. Returning soon!

Rhizocarpon geographicum

Rhizocarpon geographicum

Yellow map or world map lichen is frequently used in lichenometry, a geobotanical technique employed to estimate the age of exposure of a rock surface. Since Rhizocarpon geographicum quickly colonizes newly-exposed rock surfaces and has a known rate of growth, geologists can, for example, examine glacially-deposited rocks and determine the rate of glacial retreat. For an excellent introduction to lichenometry, read Lichens, Lichenometry and Global Warming (PDF), a short and well-illustrated paper by Richard Aston in the September 2004 issue of “Microbiologist”.

Photography resource link: Photographer and writer Freeman Patterson. To see a sampling of his photographs, click on Prints. Use the small vertical grey bars to access different albums of his images.


Thanks for the intoduction to so many new plants. It is a marvelous world we line in.

Patricia, it is indeed. I forgot to mention the scale of this photograph - it's roughly 5cm top to bottom.

Wonderful... My first blog browsing and I find a lichen photo! Good job Daniel, thanks!

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