LICHEN. Lichens don't require soil and can withstand extremely cold temperatures and dry conditions. In the far north, Lichens are extremely slow growing. (After being grazed over, may take 30 years to replenish). Lichen is an association formed between a fungus and an algae. They get their nutrients and water primarily from the air, and are very sensitive to air pollution. Lichen grows on open ground and sometimes forms thick matts on muskeg.