Appearance: A pink crust on rocks. It forms circular patches. The surface can be rough or smooth.
Depth: Lower shore.
Feeding: Lithothamnion is a producer. It makes its own food by photosynthesis. It has chlorophyll just like most land plants. The pink colour is due to other light catching pigments in the cells.
Environment: Lithothamnion grows on rocky bottoms. It needs to be covered by water most of the time. It often forms a layer on the bottom of rock pools.
Other facts: There are actually many different algae that look very similar. They all have contain a lot of calcium.
Classification: Lithothmnion is a member of the protoctista group red algae.