Rhizocarpon geographicum
Rhizocarpon geographicum | ||||||||||||
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Rhizocarpon geographicum |
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( L. ) DC. |
Rhizocarpon geographicum , also known as map lichen ,is a lichen that grows directly on bare rock.
description
The map lichen is a crust lichen, the thallus lies close to the ground or grows through it. The species is bright yellow to olive green. It can cover large areas on stones.
The lichen is divided into small angular fields that are separated from one another by a black border and run through the lichen body. Black angular fruiting bodies are sunk at the edge of the fields. The appearance of this structure is reminiscent of graphically separated areas on a map .
Like many lichens, it has extremely slow growth. Depending on the location, it grows only 0.25–0.6 mm radially outwards per year. It can reach an age of over 1,000 years and can thus be used to date the retreat of glaciers . If the growth rate at a location is known, the last ice cover can be calculated using the largest specimens.
Location
Acid silicate rock is preferred as the location . In lower altitudes and in limestone areas , this lichen occurs very rarely and then only in poor coverage. It occurs worldwide from the coast to the high mountains .
Systematics
There are several subspecies
- R. geographicum (L.) DC. ssp. arcticum (Runemark) Hertel
- R. geographicum (L.) DC. ssp. diabasicum (Räsänen) Poelt & Vezda
- R. geographicum (L.) DC. ssp. frigidum (Räsänen) Hertel
- R. geographicum (L.) DC. ssp. geographicum
- R. geographicum (L.) DC. ssp. kittilense (Räsänen) R.Sant.
- R. geographicum (L.) DC. ssp. lindsayanum (Räsänen) R.Sant.
particularities
The map lichen was voted lichen of the year 2014 by the members of the bryological-lichenological working group for Central Europe .
literature
- Marbach / Kainz: FSVO nature guide mosses, ferns and lichens. Munich 2002, ISBN 3-405-16323-4
- Wirth / Hauck / Schultz: The lichens of Germany. Stuttgart 2013, ISBN 978-3-8001-5903-1
Web links
Individual evidence
- ↑ Moss and Lichen of the Year 2014. Bryological-Lichenological Working Group for Central Europe , accessed on July 25, 2019.