• Aspicilia grisea Arnold
Aspicilia grisea
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This lichen often grows on well-lit, siliceous boulders or low outcrops. When carrying out chemical testing using Potassium hydroxide (K) the beginner will find that these crusts suddenly turn blood-red. The rather thin, grey to grey-green thallus has a cracked surface with scattered isidia forming small mounds or they may become more dispersed and granular (soredia-like). Discs are black and are not uncommon. It tests K+ red and Pd + orange.

Key characteristics

  • Grey to grey-green crust on siliceous rock; K + blood-red, Pd + orange
  • The cracked thallus has scattered clumps of granular isidia.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Aspicilia grisea Arnold. [In] LichenIreland. Accessed on 2018-07-23.