Armillaria ostoyae, also known as the dark honey fungus, owes its name to the honey-coloured mushrooms that can be identified in the autumn. On trees, the fungus appears as a white layer with a rubbery texture. The fungus is found worldwide, but the largest has been discovered in North America. Fungi of the genus Armillaria are capable of infecting more than 600 types of woody plants through their root systems.
Armillaria ostoyae, also known as the dark honey fungus, owes its name to the honey-coloured mushrooms that can be identified in the autumn. On trees, the fungus appears as a white layer with a rubbery texture. The fungus is found worldwide, but the largest has been discovered in North America. Fungi of the genus Armillaria are capable of infecting more than 600 types of woody plants through their root systems.
Root Network as Highway
The honey-coloured mushrooms facilitate the spread of the fungus's spores, allowing it to reach and infect other trees. Additionally, the fungus employs another tactic for spreading. The dark honey fungus can produce long, thin threads called hyphae. These hyphae grow along the root system of the infected tree towards other trees. In the soil, the hyphae form thick bundles that resemble shoelaces, hence the fungus is also known as the "shoelace fungus". This allows the dark honey fungus to spread easily and over large distances.
Gigantic Fungus
The largest dark honey fungus is estimated to cover an area of 8.9 km²! This fungus grows in the Malheur National Forest in the American state of Oregon. However, it is not the largest organism; that title belongs to a species of seagrass in Australia. In addition to its enormous size, it is also very old. Scientists estimate the age of this fungus to be between 2000 and 8000 years old! When trees die due to the fungus, they are essentially recycled by it. This releases new nutrients or the tree can be used for bird nests.
Glowing Fungus
There is something else remarkable about honey fungi. These fungi can emit light in the dark. This phenomenon is called bioluminescence. In Armillaria ostoyae, bioluminescence only occurs in the mycelium, the fungal network of hyphae. In other strains of the honey fungus, sometimes the mushrooms themselves also emit light. The exact function of bioluminescence in fungi is still not completely understood.