Armillaria rhizomorphs     

Black Armillaria shoe-strings00340

Armillaria ‘Honey Mushroom’ shoe-string rhizomorphs, ‘Fox Fire’  

Long-lived and among the largest organisms in the world. “Honey Mushrooms” live on wood of live and decaying trees. In Oregon there is an Armillaria solidipes that is thousands of years old and takes up 3.4 square miles. At least 10 species in US under the name Armillaria mellea. Most species are saprotrophic; a few are parasitic and cause ‘white rot‘. The rhizomorphs of Armillaria are called ‘foxfire’ because they bioluminese in the dark. They can grow at the rate of about 10 feet annually. Most species are tolerated by most people, but some are sensitive to them - especially if the mushrooms are a bit over-the-hill, are not cooked long enough, or grow on conifers. Armillaria are in the Physalacriaceae family in the Agaricales order.