• Opegrapha xerica Torrente & Egea
Opegrapha xerica
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 species grows on dry acid bark such as that of oak and yew. The thin thallus is grey, but sometimes a hint of green may be glimpsed. Discs (lirellae) are mostly simple and expanded, the spores three- to five-septate with an enlarged upper cell. The greenish colour of the epithecium in a squash of the disc is significant. It is easily overlooked for O. varia which has a brown epithecium. In Ireland, the species is thinly scattered.

Key characteristics

  • Grey thallus with greenish tinge: dry, acid bark of old trees
  • The lirellae are expanded discs like those of O. varia but have three- to five-septate spores and a greenish epithecium.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Opegrapha xerica Torrente & Egea. [In] LichenIreland. Accessed on 2018-07-22.