• Haematomma ochroleucum var. porphyrium (Pers.) Laundon
Haematomma ochroleucum var. porphyrium
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 grey-white, powder-cottony, crustose lichen should be looked for on dry, siliceous or slightly calcareous rocks and walls where it can spread to form big-sized patches. The edge of the thallus is ringed by a conspicuous white-fringed border. Discs are small and red and are scattered like little spots of blood. A dab of K (Potassium hydroxide) will turn the thallus yellow. Pd turns it yellow.

Key characteristics

  • White, circular patches with a powdery or cottony thallus surrounded by a chalk-white fringe like rug edging
  • On vertical sandstone walls and gravestones.

Original text submitted by Vince J. Giavarini

 Simms, M. J., (2016). Haematomma ochroleucum var. porphyrium (Pers.) Laundon. [In] LichenIreland. Accessed on 2018-08-20.