Armillaria ostoyae

Armillaria ostoyae
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Physalacriaceae
Genus: Armillaria
Species:
A. ostoyae
Binomial name
Armillaria ostoyae
(Romagnesi) Herink (1973)
Synonyms
  • Agaricus congregatus Bolton 1791 nom. illeg.
  • Armillaria mellea var. obscura Gillet 1874
  • Armillariella ostoyae Romagn. 1970 nom. cons.
  • Armillaria solidipes Peck 1900 nom. rej.
Armillaria ostoyae
View the Mycomorphbox template that generates the following list
Gills on hymenium
Cap is campanulate or convex
Hymenium is decurrent
Stipe has a ring
Spore print is white
Ecology is parasitic
Edibility is choice

Armillaria ostoyae (synonym Armillaria solidipes) is a species of fungus (mushroom), pathogenic to trees, in the family Physalacriaceae. In the western United States, it is the most common variant of the group of species under the name Armillaria mellea. A. ostoyae is common on both hardwood and conifer wood in forests west of the Cascade Range in Oregon, United States. It has decurrent gills and the stipe has a ring.[1] The mycelium invades the sapwood and is able to disseminate over great distances under the bark or between trees in the form of black rhizomorphs ("shoestrings").[2] In most areas of North America, Armillaria ostoyae can be separated from other species by its physical features: cream-brown colors, prominent cap scales, and a well-developed stem ring distinguish it from other Armillaria. Like several other Armillaria, the mycelium of Armillaria ostoyae can display bioluminescence, resulting in foxfire.[3]

Armillaria ostoyae grows and spreads primarily underground, such that the bulk of the organism is not visible from the surface. In the autumn, the subterranean parts of the organism bloom "honey mushrooms" as surface fruits.[2] Low competition for land and nutrients often allow this fungus to grow to huge proportions, and it possibly covers more total geographical area than any other single living organism.[2][4][5] A spatial genetic analysis estimated that an individual specimen of A. ostoyae growing over 91 acres (37 ha) in northern Michigan, United States, weighs 440 tons (4 x 105 kg).[6][7]

Another specimen in northeastern Oregon's Malheur National Forest is possibly the largest living organism on Earth by mass, area, and volume – this contiguous specimen covers 3.7 square miles (2,400 acres; 9.6 km2) and is colloquially called the "Humongous fungus".[2] Approximations of the land area occupied by the "Humongous fungus" are 3.5 square miles (9.1 km2) (2,240 acres (910 ha)), and it possibly weighs as much as 35,000 tons (approximately 31,500 tonnes), making it the world's most massive living organism.[8]

  1. ^ "Armillaria ostoyae, Dark Honey Fungus". first-nature.com. Retrieved 23 October 2019.
  2. ^ a b c d Schmitt CL, Tatum ML (2008). "The Malheur National Forest: Location of the world's largest living organism (the Humongous Fungus)" (PDF). Forest Service, US Department of Agriculture. Archived from the original (PDF) on 3 August 2019. Retrieved 16 December 2018.
  3. ^ Rishbeth J. (1986). "Some characteristics of English Armillaria species in culture". Transactions of the British Mycological Society. 86 (2): 213–218. doi:10.1016/S0007-1536(86)80147-4.
  4. ^ "Biggest living thing". Extreme Science. 1 December 2010.
  5. ^ Puiu, Tibi (6 February 2015). "The largest organism in the world". ZME Science. Retrieved 20 February 2015.
  6. ^ Cite error: The named reference Anderson was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference daley was invoked but never defined (see the help page).
  8. ^ Vince Patton (12 February 2015). "Oregon Humongous Fungus Sets Record As Largest Single Living Organism on Earth (7-minute documentary video)". Oregon Field Guide. Retrieved 23 September 2019.