• Brainly User
  They are simple slow-growing plant which typically forms a low crust-like, leaf-like, or branching growth on rocks, walls, and trees.
1 5 1
The Brainliest Answer!
Lichen are called compound plants as algae and fungi lived together in close associations, as as result of which both are beneficial fro each other. This relationship is called symbiosis. They occur as greyish- green growth on rocks, bark of the trees or on the ground 
2 5 2