Armillaria mellea
"The Honey Fungus"


 
 Agar culture of Armillaria mellea.  Note the creeping "rhizomorphs".  Rhizomorphs are "rootlike" structures composed of dense bundles of mycelium, which aid in the survival, and spread of the fungus.  The dark pigment is melanin which helps protect the mycelium.
 
Top: Armillaria mellea grown on PDY agar for 21 days @ 25 degrees Celsius
Bottom: Armillaria mellea grown on rye grain for 40 days @ 25 degrees Celcius
 
Armillaria mellea is not the brightest glowing species on agar culture, however on wood substrates, the mycelium is reported to glow much brighter.  The phenomenon has been referred to as "foxfire" or "willow the wisp".  Armillaria is a pathogen of trees; whole forests can be wiped out he invading fungus, leaving "ghost" trees.  Rhizomorphs form  extensive underground networks, and genetically identical colonies have been known to cover areas equivalent to several football pitches, making this species the largest organism on earth! 



Copyright LUXGENE 2000