Answer: lichens

AnswerCrossword Clue
LICHENS

Fungus-alga unions

LICHENS

Growths on rocks or tree trunks

LICHENS

Rock growths

LICHENS
Rock plants
LICHENS
Plants for rock gardens.
LICHENSMosses.
LICHENSMosslike growths
LICHENSFungous growths
LICHENSGrowths on tree trunks or rocks