What Makes a Fungus a Fungus?

king boletusFungi have several things that make them fungi and not plants, mammals, or something else.  Here are a few of the most important things that make a fungus a fungus:

  • Fungi do not have chlorophyll.
  • Fungi reproduce by spores.
  • Can’t make their own food.
  • Most fungi grow as long, thin threads called hyphae.


A fungus or fungi if we are talking about more than one, is an organism that lives mostly as tiny, hair like structures that we can’t see since they are so small. Here are the main parts of a fungus:

fungus diagramHyphae – These are the tiny, thin hair like structures that comprise the body of the fungus.

Mycelium – Lots of hyphae growing together, looking like a cobweb.

Mushroom – The spore bearing, fruiting body of a fungus.


There are four main kinds of fungi:

Decomposer – Feed on dead things. They break down dead animals and plants. When this happens, nutrients are returned to the soil.

Parasite – Feed on other living things. These fungi live on and feed on live trees and plants. By doing so, they are slowly killing their host plant. A good example of this is a bracket fungus.

Mutualist – Feed on other living things. These live together with a plant and their relationship benefits both the plant and the fungi. For example, they may live on the roots of a plant and help it grow, while the plant gives sugar to the fungi for its food.

Endophyte – Feed on other living things. These live within something else and are still not fully understood.

A bracket fungus

A bracket fungus growing on a tree.


Here are some of the many things that fungi do:

  • Break down wood and leaf litter. As such they are the recyclers of the natural world.
  • Help trees and plants grow both by growing on their roots and by making good soil and nutrients.
  • People use fungi to make medicines.
  • People use them to make food, such as bread, cheese, and beer.
  • Provide food for animals that eat the fruit bodies (mushrooms).


A mushroom is the fruit of a fungal organism that makes them.

A fungus makes a mushroom in order to reproduce or make new fungi.

For example, an apple is the fruit of an apple tree and it contains the seeds to make new apple trees. For fungus, a mushroom holds the spores and helps make new fungus.

Can we eat the mushrooms we find?


Despite the fact that you may enjoy eating mushrooms with your food, you absolutely should not eat mushrooms you find in the wild. There are so many different kinds of mushrooms, some of which are poisonous, that it is very difficult to be certain what kind you have found.

This diagram shows the main parts of a mushroom.

mushroom diagramMycelium: The large amount of hyphae located in the soil, tree, or whatever the fungi is living in.

Volva: A broken, sack like covering at the base of the mushroom’s stem.

Stem: A stalk that supports the cap.

Cap: The top of the mushroom.

Gills: The structures on the underside of a mushroom’s cap that hold the structures where the spores come from.

Note: Some spores are on the underside of a mushroom’s cap, but others may be inside of a mushroom cup.