What is lichen?
When an alga and fungus physically intertwine in a very close symbiotic relationship, they actually form an entirely new growth called lichen. Lichen is a kind of primitive plant species that’s nothing more than strands of alga linked with roots and branches of a fungus that together absorb minerals from the ground and conduct photosynthesis. Lichen can grow almost anywhere, from moist bark to recently cooled lava to frozen rocks. Unlike most parasitic or symbiotic relationships, when a fungus and alga grow together so tightly they can’t be separated, they qualify as a different kind of material. Biologists have agreed that lichen straddles the monera and fungi kingdoms of living things since it is part one and part another. Its body, called a thallus, can be made of different types of fungi and blue-green algae, which will determine how much water it needs or to what it can attach. The alga, called the physobiont, contains chlorophyll, therefore it can photosynthesize energy that it p
