This lichen is by far the most common maritime lichen found on the coast. The thallus forms extensive black patches that penetrate the surface of siliceous and limestone rocks. They often develop a chinky surface which looks similar to cracked dry mud, or produce low rounded bumps that protrude from the surface.

It can form a striking black band on rock from the high intertidal zone into the splash zone. The width of the band varies with exposure (less than 1 meter wide in protected areas, and more than 5 meters wide at exposed locations).

Uses the suns energy.

This lichen is often mistaken for weathered oil. Most lichens are a symbiotic relationship between a fungus and an algae. Photo Dr Allison Knight

Photo Credit Rod Morris. Photos available from www.rodmorris.co.nz
http://www.seaweedsofalaska.com/species.asp?SeaweedID=128 (accessed 17/04/13)