""Amanita caesaria," he said. "Not what you think," he added when he saw the look on my face."
Amanita caesura, an edible mushroom
Creative Commons Attribution Share AlikeAmanita caesura, an edible mushroom - Credit: Archenzo
Amanita phalloides, a poisonous mushroom
Creative Commons Attribution Share AlikeAmanita phalloides, a poisonous mushroom - Credit: Archenzo

 Amanita caesaria is an edible mushroom, considered to be the favourite of the Roman emperors (hence its name). However, as Henry goes on to say, it resembles the highly poisonous Amanita phalloides, and is therefore not a popular choice among modern mushroom pickers.

Amanita phalloides has been implicated in the deaths of the Roman Emperor Claudius and  Holy Roman Emperor Charles VI.