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,Volk and Burdsall (1995), p. 8. 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.
The genus once served as a wastebasket taxon for many agaric mushrooms with a white spore print, gills attached to the stem, and an annulus. Due largely to differing interpretations on the limits of the genus, over 270 species and varieties have been placed in Armillaria or its synonym Armillariella. A comprehensive 1995 study by Tom Volk and Harold Burdsall evaluated all of the epithets that have been used in Armillaria or Armillariella. They determined that about 40 species belong to Armillaria sensu stricto (in the strict sense); the remaining names belong to species that are distributed among 43 other modern fungal genera.Volk and Burdsall (1995), p. 6.
Many species are difficult or impossible to distinguish from each other using observable characteristics; laboratory incompatibility tests are often used on pure cultures to reliably determine species. Because of the difficulties posed by routine species identification, the use of DNA sequencing and phylogenetic approaches has become a standard method to help clarify relationships between species. Species differ in their geographical distribution and ecological position, host specificity, microscopic and macroscopic features, and also in their aggressiveness in colonizing wood hosts. The following list of Armillaria species is based on the taxonomic overviews provided by Volk and Burdsall in 1995,Volk and Burdsall (1995). David Pegler in 2000, and reports of new species that have been published since then.
Species Key to the table of species below
ImagePhoto of the Armillaria species. NameThe binomial name of the Armillaria species. AuthorityThe author citation—the person who first described the species using an available scientific name, eventually combined with the one who placed it in Armillaria, and using standardized abbreviations.YearThe year in which the species was named, or transferred to the genus Armillaria. Where the actual year of publication (as defined for the purpose of priority) differs from the date given in the material, the latter date is given in quotes.DistributionThe distribution of the species; unless otherwise indicated, this information is obtained from Volk and Burdsall (1995), and Pegler (2000).
ImageNameAuthority YearDistribution Armillaria affinis 1995 Armillaria altimontana 2012 Western North America Armillaria apalosclera 1982("1981") Asia Armillaria aotearoa Hood and Ramsfield. 2016 New ZealandArmillaria borealis Marxm. & Korhonen 1982 EurasiaArmillaria calvescens Bérubé & Dessur. 1989 Eastern North AmericaArmillaria camerunensis 1995 AfricaArmillaria cepistipes Velen. 1920 Armillaria duplicata 1887 IndiaArmillaria ectypa 1965 EuropeArmillaria fellea 1983 AustraliaArmillaria fumosa Kile & Watling 1983 AustraliaArmillaria fuscipes Petch 1909 Armillaria gallica Marxm. & Romagn. 1987 Armillaria gemina Bérubé & Dessur. 1989 Eastern North AmericaArmillaria griseomellea 1983 North and South AmericaArmillaria heimii Pegler 1977 AfricaArmillaria hinnulea Kile & Watling 1983 AustralasiaArmillaria jezoensis J.Y.Cha & Igarashi 1994 JapanArmillaria limonea 1977 Armillaria luteobubalina Watling & Kile 1978 Armillaria mellea 1871 Armillaria melleorubens 1887 North and Central AmericaArmillaria mexicana 2018 MexicoArmillaria montagnei 1973 Armillaria nabsnona T.J.Volk & Burds. 1996 Armillaria novae-zelandiae 1973 Armillaria omnituens 1887 IndiaArmillaria pallidula Kile & Watling 1988 AustraliaArmillaria paulensis Capelari 2008 South AmericaArmillaria pelliculata Beeli 1927 AfricaArmillaria procera Speg. 1889 South AmericaArmillaria puiggarii Speg. 1889 South AmericaArmillaria sinapina Bérubé & Dessur. 1988 Armillaria singula J.Y.Cha & Igarashi 1994 Armillaria socialis 1889 Armillaria solidipes, popularly known as Armillaria ostoyae Peck 1900 Armillaria sparrei 1973 North and South AmericaArmillaria tabescens 1921 Armillaria tigrensis 1983 South AmericaArmillaria umbrinobrunnea 2010 South AmericaArmillaria viridiflava 1995 Armillaria yungensis 1973 South America
Notes
References
Cited literature