Stumped by a Crossword Clue? Discover the Answer to ‘Growths on Rocks and Bark’ Here!

Lichens are complex organisms composed of a symbiotic association between a fungus and an algae or cyanobacterium, growing on rocks and tree bark. They are widely distributed throughout the world, and their many different species can be found in a range of different environments, from the arctic tundra to the hot deserts. They play an important ecological role as primary producers, converting energy from the sun into organic matter, and providing a source of food and shelter for a variety of other organisms. Lichens also have a number of practical applications, including their use as indicators of air pollution, and in the production of dyes, medicines, and other useful compounds.