lichens on a rock retaining wall

lichens rock retaining wall fungus together synergetic mutually beneficial symbiotic alga algae limestone splatters outdoor nature growing crusty symbiosis mutual mutualistic missouri moss associated cooperative interdependent reciprocal ozarks fassnight unified mass mixed complementary reciprocated requited dependent interactional twosided interchanged reciprocative codependent reliant symbiology symbioses symbiotically confederated conglomerate undivided merged amalgamated give appearance paint found polluted areas grow barren wood log tree trunk soil abandoned walls aquatic habitats rocks logs trunks splatters