Mosses and lichens adorning trees of this shaded slope are plants called "epiphytes" (that grow on other plants) and are not parasites for their supports. Lichens are the result of a symbiosis between a fungus and an alga. The carpet of mosses and "clumps" of lichens that color the wood of this ubac slope or north-facing slope (slope which receives little sunshine) testifies to the fact that these plants mainly appreciate wet and cool areas.