Armillaria ostoyae
English: Humongous fungus; Honey mushroom.
German: Dunkle Hallimasch; Gemeine Hallimasch.
Synonym: Armillaria solidipes.
Clades: Physalacriaceae.
Region: northern Hemisphere, Europe; Cascade Range in Oregon, United States.
Habitat: on hardwood, conifer; forests west of the Cascade Range in Oregon, United States.
Use: edible.
Mycology
Type: mycelium invades the sapwood, disseminate over great distances under the bark or between trees, forming coalesced colonies of flat, dark brown to black rhizomorphs, called shoestrings or rhizomorphs; grows and spreads primarily underground; prefers low competition for land and nutrients; grows to huge proportions, up to 37 ha and 440 tons.
Fruit body: autumn; "honey mushrooms".
Cap: cream-brown, prominent scales; decurrent gills; cream-brown.
Stipe: well developed ring.
Hymenium: decurrent gills.
Spore print: white; two mating types; dispersed by wind, animals.
Pathogenic
It is pathogenic to Pseudotsuga menziesii, Abies, Pinus, Tsuga heterophylla and others, especially young ones, in coastal regions. Infection of trees can be treated with Hypholoma fasciculare, competes well with Armillaria ostoyae or removing diseased stumps, maintaining biological diversity, reducing insect pest buildup.