Appearance: Encrusting or branching on rocks. Colours vary from grey, grey-green, orange and black.
Depth: Splash zone above high tide level.
Feeding: Lichens are producers. They make their own food by photosynthesis.
Environment: Lichens grows on rocks in the splash zone above the high tide level. They are likely to be splashed by sea water but most are really land organisms.
Other facts: Each lichen is actually a close mutualistic association between a fungus and an alga. The fungus provides protection from drying while the alga produces food for both organisms. Lichens rely on the atmosphere for their supply of water and nutrients. They are very sensitive to air pollution.
Classification: Lichens are members of the protoctista.