Armillaria ostoyae - Опёнок тёмный - Dark Honey Mushroom

Armillaria ostoyae - Опёнок тёмный - Dark Honey Mushroom - Dunkler Hallimasch 4/1/11

Armillaria ostoyae, commonly known as the Dark Honey Mushroom or Dunkler Hallimasch in German, is a medium-sized mushroom species belonging to the Physalacriaceae family. The cap of this fungus measures 4 to 15 cm in diameter, with a convex to flat shape and a smooth surface. The cap color ranges from dark brown to reddish-brown, often with a slightly darker center. The gills of Armillaria ostoyae are adnate to slightly decurrent (running down the stem) and white to cream in color. The stem is 5-15 cm tall and 1-3 cm thick, with a white to yellowish-brown color and a slightly bulbous base. Armillaria ostoyae can be found in temperate forests across Europe, Asia, and North America. It grows in clusters around the bases of living or dead trees, particularly on conifers and hardwoods, from late summer to late autumn. The chemistry of Armillaria ostoyae is not well studied, but it is considered an edible mushroom when cooked, with a mild, slightly sweet taste. The spores of Armillaria ostoyae are white, elliptical, and measure 7-9 x 5-6 micrometers. They are produced in basidia and are released into the environment for reproduction and dispersal. Armillaria ostoyae is known for its ecological role as a wood decomposer, breaking down dead wood and recycling nutrients within forest ecosystems. This process contributes to the cycling of nutrients and overall forest health. The fungus is also known as a pathogen, causing root rot in various tree species, leading to decline and death. Its pathogenicity is considered to be more aggressive than that of Armillaria mellea and Armillaria borealis. One notable aspect of Armillaria ostoyae is the discovery of a massive colony in the Malheur National Forest in Oregon, USA, which is believed to be one of the largest and oldest living organisms on Earth. Armillaria ostoyae has been studied for its potential medicinal properties, with research suggesting that it may contain compounds with antioxidant, anticancer, and immunomodulatory effects.