close up of various lichen growing on stone.

pattern texture nature lichen rock boulder natural background moss closeup stone fungus macro surface plant abstract fungi radiata dimelaena brown crustose aurella candelariella buellia verrucaria apothecia grey fung wild verrucariaceae photosynthesis foliose cortex mossy cover algae pullata structure growth ecology fungal biology yellow wall colorful symbiotic alga old mushroom shape