Answer: lichen

AnswerCrossword Clue
LICHENMosslike plant.
LICHENSource of litmus
LICHENPlant life of Antarctica.
LICHENThallophyte.
LICHENIceland moss.
LICHENMoss.
LICHENRock plant.
LICHENReindeer moss.
LICHENRock garden plant.
LICHENRock greenery.
LICHENForest growth
LICHENRock cruster
LICHENFungus-algae alliance
LICHENIt may grow on rocks
LICHENMossy growth
LICHENIceland moss
LICHENGrowth on a tree
LICHENWhat a rolling stone is unlikely to gather
lichento cover with flowerless plants
LICHENAlga-fungus symbiosis
LICHENOakmoss, e.g.
LICHENGrowth on a rock
LICHENRock growth
LICHENTree growth
LICHENFungus-alga union
LICHENWoodsy growth
LICHENSymbiotic growth
LICHENAlga-fungus combination
LICHENFungus-alga symbiosis
LICHENBeard moss, for one
LICHENGrowth on trees and rocks
LICHENRock fungus
LICHENRock plant
LICHENTree-trunk cover, perhaps
LICHENGrowth on rocks
LICHENFungus + alga
LICHENGrowth on rock walls