What mushrooms are called useful symbionts?

Symbiotic mushrooms grow alongside certain trees. The symbiosis of a fungus and a tree lies in the fact that the mycelium of the fungus entwines the root of the tree and grows together with it, penetrating into its tissues. This fusion is called the fungus root. The fungus draws out the necessary substances from the plant. This process does not harm the plant at all. Thanks to this, the plant can extract minerals from the soil. The symbiont mushrooms include almost all edible mushrooms, as well as poisonous ones, such as toadstools and fly agarics.