Amanita bisporigera is among the deadliest mushrooms on earth and contains enough toxins to kill a healthy adult with just one bite.
- Cap: 5-12 cm; almost oval, becoming convex, then broadly convex to nearly flat in age; smooth; dry; stark white, sometimes discoloring towards the center in age; the margin (usually) not lined
- Spore print: white
- Spores: 7-10 x 6.5-8.5 µ smooth; broadly elliptical or nearly round; amyloid
- Bruising: yellow
- Gills: attached or free from the stem, white and close
- Stipe: 7.5-20 cm long; 0.5-2 cm thick; more or less equal, or more frequently tapering somewhat to apex and flaring to an enlarged base; smooth or shaggy; white; with a persistent skirtlike ring that almost always remains into maturity; without a rim at the base; with a white, sacklike universal veil encasing the base
- Veil: thin and white, covers the gills during development then tears away and hangs from the stipe
Amanita bisporigera and Amanita phalloides (the death cap) are responsible for the overwhelming majority of deaths due to mushroom poisoning. The toxin responsible for this is amatoxin. Symptoms do not appear for 5 to 24 hours, when the toxins may already be absorbed and the damage (destruction of liver and kidney tissues) done.
Amanita bisporigera cultivation in a lab environment has been uncommon if not impossibile due to the symbiotic mycorrhizal relationship of this mushroom to its host trees.