What do you know about the methods of reproduction, growth rate and lifespan of lichens?

Lichens can thrive in the harshest conditions. They can take hold in places where other organisms are unable to exist. The growth process is very slow. Most lichens of the crustacean species rarely increase by more than 1 mm per year. Other forms grow a little more quickly, they grow no more than 10 mm per year. Consequently, large species of lichens are of considerable age. Some representatives of the Arctic species are over 4000 years old. And lichens reproduce in a variety of ways: vegetative, sexual and asexual.