page_title: List of Armillaria species
section_title: Species
hierarchical_section_title: List of Armillaria species / Species
caption_attribution_description: English: The mushroom Armillaria gallica Marxm. &amp; Romagn. Specimen photographed in Wayne National Forest, Athens Co., Ohio, USA.
context_page_description: Armillaria is a genus of fungi commonly known as honey mushrooms. First treated by Elias Magnus Fries in 1821, and later assigned generic rank by Friedrich Staude in 1857, Armillaria is classified in the family Physalacriaceae of the Agaricales, the gilled mushrooms. The majority of species in Armillaria are saprotrophic and live mainly on dead wood, but some are parasites that can cause root and butt rot in over 600 species of woody plants. Some Armillaria species form mycorrhizae with orchids; others, such as A. gallica, A. mellea, and A. tabescens, are bioluminescent.
  Armillaria species form fleshy, white-spored mushrooms with a cottony or membranous veil that typically forms a distinct annulus on the stem. The fruit bodies usually occur in autumn in large clusters at the base of the stem or roots. Armillaria species can produce rhizomorphs—rootlike aggregations of hyphae—that can form massive, long-lasting underground networks. The growth of the rhizomorph networks allows for tree-to-tree spread of the fungus even when direct contact between diseased and healthy plants is not possible.
context_section_description: Key to the table of species below
caption: A. gallica
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