Fungus
Map Lichen
Rhizocarpon geographicumAlso known as Geographic Lichen, Yellow Map Lichen
Map lichens form intricate, bright yellow-green crusts patterned with fine black fungal boundaries across exposed rock surfaces. Growing at exceptionally slow rates of under a millimeter per year, these long-lived organisms are used in lichenometry to date retreating glaciers and ancient stone structures. They thrive in exposed arctic and alpine environments where hard siliceous rock and clean air are abundant.
CrustoseAlpineSlow-Growing
—observations
—countries
—peak records
Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Diet & preyAutotrophic (photosynthetic green algal partner paired with fungus)
Predators
- Mites
- Springtails
- Snails
ThreatsAir pollution, atmospheric warming, direct physical disturbance
HabitatsAlpine rocks, arctic tundra, mountain summits, non-calcareous stone
Life span1,000 to over 9,000 years
Classification
- OrderRhizocarpales
- FamilyRhizocarpaceae
- GenusRhizocarpon
- SpeciesRhizocarpon geographicum
Range data is not available yet.
Interaction riskLow
- Low
- Moderate
- High
- Very high
- Why interaction risk is low
- Safe to observe at a normal distance.
Responsible observation
- Examine boundary lines: Look closely at the black borders that outline individual colonies like continents on a map.
- Assess local air quality: Use their presence as an indicator of exceptionally low atmospheric pollution.
Frequent Companion Jason Hollinger (original photograph), Papa Lima Whiskey (derivative edit) / CC BY-SA 3.0 · cc-by-sa
Image unavailableCompetitor 
Close Relative (c) Zihao Wang, some rights reserved (CC BY) · cc-by
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Alpine Heights
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