• Thelidium pyrenophorum (Ach.) Mudd
Thelidium pyrenophorum
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The thallus of this species can be grey or white, variably thin and superficial or occasionally immersed. The large discs (perithecia = 0.30.7mm diam.) form dots on basic siliceous rock surfaces and limestone. The discs possess an outer sheath (involucrellum) but are not covered over by a layer of thallus. The one-septate spores have an average size range of 2128 x 1013m. There are only a handful of Irish records.

Key characteristics

  • Thallus white or grey, visible or immersed; perithecia with an involucrellum but lacking an additional layer of thallus covering the top
  • Spores one-septate, medium sized; dry, basic siliceous rock and limestone.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Thelidium pyrenophorum (Ach.) Mudd. [In] LichenIreland. Accessed on 2018-07-19.