• Aspicilia laevata (Ach.) Arnold
Aspicilia laevata
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This uncommon aquatic crustose lichen can be recognised in the field by its K+ yellow or red, Pd+ orange, spot test reactions. The thallus is black-olive green changing to grass green when wetted within the amphibious zone or a stream or river. Discs are common, crater-like. Often found squeezed between the thalli of other lichens such as Rhizocarpon lavatum and Ionaspis lacustris by searching bouldery sections of tree-lined river corridor. In Ireland: occasional in upland areas.

Key characteristics

  • Round, crater-like discs, almost black on a green to black thallus; Pd+ orange, K+ yellow or red (this last reaction sometimes patchy)
  • Growing in amphibious zone of shaded, upland streams and rivers.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Aspicilia laevata (Ach.) Arnold. [In] LichenIreland. Accessed on 2018-08-16.