• Placynthium nigrum (Huds.) Gray
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Placynthium nigrum
© Mike Simms
Placynthium nigrum
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(Map updated: 11 August 2009)

In limestone country, on slow-drying rocks or tombstones or on old-mortared walls, the black, velvet-textured thallus of this lichen will be quick to draw the eye. Close observation shows this to be an elegant species composed of tightly packed (like carpet pile) collaloid squamules sometimes capped by tiny glossy-black discs. A ring of blue felt-like prothallus is usually present around the border which, on seeing, immediately confirms identification.

Key characteristics

  • Almost jet black, velvety thallus
  • Edged with a blue-felt-like border.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Placynthium nigrum (Huds.) Gray. [In] LichenIreland. Accessed on 2020-05-26.