1 Iritis is uncommon, but can be due to trauma, infections, or autoimmune conditions. Symptoms include pain, red eye, and often, decreased vision.  Optic neuritis. The nerve travelling from the back of the eyeball into the brain can become inflamed.
Oak root fungus, or white rot, is a widespread disease that becomes visible just beneath the bark and on roots. What looks like layers of light brown to tan mushrooms form in clusters at the base of the trees.
Fungi (plural for fungus) are different from both viruses and bacteria in many ways. They are larger, plant-like organisms that lack chlorophyll (the substance that makes plants green and converts sunlight into energy). Since fungi do not have chlorophyll to make food, they have to absorb food from whatever they are growing on.