• Xerotrema megalospora Sherwood & Coppins
Xerotrema megalospora
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This rare lignum specialist appears to be more fungus than algae. Search for the dark brown discs (0.3-0.6mm diam.) on the dry wood of pine and yew. These are indented like a new tractor tyre and carry coarse radial cracks. The massive spores (to 170ųm long) are muriform (multi-celled). In Ireland, the lichen grows on yew lignum in County Kerry. I have seen it on the branches of pine, growing in the native Caledonian pinewoods of Scotland.

Key characteristics

  • Dark brown discs like tractor tyres in miniature growing on bare lignum (yew or pine)
  • Massive muriform spores.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Xerotrema megalospora Sherwood & Coppins. [In] LichenIreland. Accessed on 2018-08-16.