Umbilicaria hyperborea

This lichen is very common and is one of the most common species found on exposed bedrock. It consists of small scaly flaps of tissue in which each flap of tissue or thallus is attached to the bedrock from a central holdfast. When dry, these lichens are very fragile and difficult to collect because they break into many tiny fragments when you try to remove them from the bedrock. They are much easier to collect when they are moist.

 

When dry, the upper surface is very dark greyish brown or black and is very wrinkly in appearance whereas the underside remains quite smooth.

If you look closely, the upper surface has scattered round black mounds that are deeply lined. These are apothecia which are the fruiting structure of the fungal partner of the lichen. This is equivalent to a mushroom that you see in the forest. Both release fungal spores.

When wet, blistered rock tripe lichen looks quite different. It turns a brownish green colour. Algae is present just below the upper surface of the lichen which gives it the greenish colour. In this photo you can see the black apothecia remain black because they lack algae.