We are made of fine threads that look a bit like cotton wool! The fine threads are called hypha (hi – fa) or hyphae (hi – fee) when there are more than one. Lots of hyphae together make a ‘mycelium’ (my-seal-e-um)
Our mycelium can grow over very long distances which means we can reach water and nutrients in the soil that plant roots can't reach. Some of us grow around the roots of plants and give water and nutrients to them to help them to grow. In return the plants give us sugars that they have made using energy from the sunlight. We are called fungus roots or 'mycorrhizas' (my-co-ry-zas).
Fly Agaric (Amanita muscaria) is a mycorrhiza and it helps Pine and Birch trees to grow.
Fungal cell walls are made of chitin
The cell walls of fungal hyphae contain chitin which is made of long chains of special sugars all linked together. Chitin makes the shells of crabs and the hard case (exoskeleton) of some insects too.