Amanita phalloides is commonly called the Death Cap.  It is natively a European mushroom which was introduced to the US by at least the 1970‘s with its associated trees.  It is now in many continents including Australia, parts of Africa and South America.  The caps are greenish-yellow.  Gills and veil are white with hints of yellow-green.  It smells faintly sweet to cloyingly sickly sweet.  The majority of fatalities due to mushroom poisoning are a result of consumption of this mushroom.  It apparently looks similar to straw mushrooms and out west is confused with them.  One has to eat only half a cap to be threatened with an agonising death.
It is believed that Emperor Claudius and the Holy Roman Emperor Charles the 6th were deliberately poisoned by the Death Cap.  Its toxic ingredient damages the liver and kidneys - usually fatally.  One of the only known antidotes is a milk thistle compound. 058-001

« Scleroderma citrina is packaged in Europe and sold as a substitute for truffles. A small amount eaten raw has been reported to cause muscles to lock up, temporary vision problems and deep sleep. 057-001
EDIBLE MUSHROOMS & POISONOUS LOOK-A-LIKES by Dianna Smith
Puffballs are undifferentiated inside. Amanitas show the whole mushroom. Deadly ‘Destroying Angel,’ is the most poisonous of our native eastern Amanitas and accounts for 90% of the deaths by wild mushrooms. It contains cyclopeptides that destroy the liver. There are two equally poisonous and virtually indistinguishable amanitas, Amanita verna and Amanita bisporigera. It is found June through October under hardwoods. The toxin is a protein by the name of alpha amanitin, a cyclopedtide which works by slowly attacking an enzyme in the liver. Both the liver and the kidneys are ultimately affected about 6 to 24 hours after consumption. Symptoms include violent cramps and diarrhea. There is a false remission of symptoms by the third day. On the 4th and 5th day the liver and kidneys continue to break down. Death follows unless a liver transplant can be performed. The same toxin is in the Autumn Galerina. 059-001 »