Ginny B's picture

Definition of marine lichens

I live close to the sea and wonder if someone could please tell me when and where is a lichen a marine lichen?

Is it where it is covered daily by the tide; or where the sea only sometimes covers it; or where it is receives sea spray in stormy weather such as on cliffs; or is the definition dependent on which fungus and alga are present?



synan's picture

Marine lichens

Hi Ginny,

I'm not aware of a strict definition, but someone else may be able to supply one.

It appears that Verrucaria serpuloides in the Antarctic region is the world's only 'true' marine lichen, able to survive being permanently submerged. More generally, I think anything in the intertidal zone qualifies as a marine lichen - eg Verrucaria maura. Species in the spray zone are probably best described as maritime lichens, otherwise we might end up with thrift (Armeria maritima) as a marine plant!


Ginny B's picture

Marine Lichens

Hi Nigel,

Thank you for your clear explanation.

Love the idea of thrift (Armenia maritima) being a marine plant! :) That explains the difference between marine and maritime to me particularly well.

When I started looking at the rocks on the beach I hadn't expected to find so many lichens that must regularly be sea covered. It seems I now also need to learn what kind of rocks I'm looking at too in order to identify lichens more accurately.


synan's picture


You're not alone. I am no geologist and I often struggle with rocks.