There are other fungi which you’ve seen oftener than toad stools. They are—
Molds
You’ve often seen the mold which comes on bread which has been left in a rather dark, warm, moist place.
The mold comes from the thousands of germs in the dust in air. These germs settle down and use anything possible for food, and send out spore-dust to make more germs.
While they are growing and making spore cases, they appear as molds and mildews.
The germs in the dust are too tiny to be seen without a microscope, and their near relatives—
Bacteria
are about the tiniest of living things.
They grow everywhere. Some do us harm and some benefit us wonderfully.