Lichens are not a single plant. A lichen consists of an upper part of interwoven fibres related to the fungus and a layer of more loosely fibrous structures related to the fungus that surrounds the algae. The algae can carry out photosynthesis and feed the fungi. The fibrous structures that make up the fungi adds support to the algae and keeps the algae from drying out. Moss usually grows as low, dense, carpet-like masses on tree trunks, rocks, or moist ground.
Mosses create organic matter and make the local habitat more suitable for seed-bearing plants.
Mosses thrive in humid climates and prefer moist, shady places, and grow on trees, rocks, rotten wood, and soil. Peat mosses accumulate in deposits that may be several hundred metres thick. On rocky outcrops, mosses may grow along cracks or fractures in the rock. The crack is a trap for small amounts of soils and water naturally seeps along these cracks. The soil and water provide essential nutrients for the moss.