LichenIreland
  • Rhizocarpon geographicum (L.) DC. [35]
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Rhizocarpon geographicum
© Robert Thompson
Rhizocarpon geographicum
© Robert Thompson
Rhizocarpon geographicum
© Robert Thompson
Rhizocarpon geographicum
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(Map updated: 11 August 2009)
Rhizocarpon geographicum
© Mike Simms
Rhizocarpon geographicum
© Mike Simms
 

Known as the ‘map lichen’ this conspicuous, mosaic-forming, crustose species has a bright yellow, mostly smooth, angular, areolate thallus, developed above a conspicuous black underlayer visible through the cracked surface and also around the margin. Discs abundant, evenly distributed, small, black, irregular. Hard acid rocks, walls and roofing slates; upland areas mainly.

Key characteristics

  • Contrasting yellow thallus and black angular discs
  • Black margins separate adjacent colonies.

Original text submitted by Vince J. Giavarini

 
 Simms, M. J., (2016). Rhizocarpon geographicum (L.) DC. [35]. [In] LichenIreland.
http://www.habitas.org.uk/lichenireland/species.asp?item=39755 Accessed on 2018-10-17.