A vocabulary of landscape — a landscape of words 1068 entries

lichen

LY-ken
A composite organism — fungus and algae living as one, growing on rocks, trees, and bare ground in conditions no plant could survive. Lichens are the first colonizers of bare stone. Some Arctic lichens are thousands of years old. They grow a millimeter.
Etymology
Greek: leichēn (lichen, liverwort), possibly from leichein (to lick), for the way it clings to surfaces.