• Lithographa tesserata (DC.) Nyl.
Lithographa tesserata
Click on map to open large map in new window
(Map updated: 11 August 2009)

Click here to view an interactive map of the Northern Ireland dataset as currently collated by CEDaR.
The map is generated through the NBN Gateway using their Interactive Mapping Tool.


This is a conspicuous siliceous rock-inhabiting lichen of moist, upland, vertical rock faces. It has a white to grey areolate thallus studded with small clusters of short black, stumpy, Graphis-like, slit-topped discs (lirellae). The species has simple spores. Spot tests: K+yellow-red, PD+ orange. The one old record from County Galway is now considered doubtful. A fresh search for the species in Ireland is required.

Key characteristics

  • K+ yellow-red, PD + orange thallus, white to grey, areolate, 4-5cm diam.; prothallus black, visible between the areoles
  • Discs (lirellae) stout, clustered with simple spores; shady vertical walls of siliceous rock in the mountains.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Lithographa tesserata (DC.) Nyl.. [In] LichenIreland. Accessed on 2018-07-23.