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.
A plate of dried black fungus. Overview. Black fungus, or Auricularia polytricha, is sometimes known as wood ear, cloud ear, Judas ear or tree ear. It is a mushroom that is dark brown to black and native to Asia and some Pacific islands with humid climates, according to the Mycological Society of San Francisco.