Final answer:
The name 'fly agaric' originates from the mushroom Amanita muscaria, and it is theorized to be called so either because of its historical use as a fly killer or due to its hallucinogenic properties causing 'fly-like' behavior.
Step-by-step explanation:
The common name 'fly agaric' refers to the Amanita muscaria mushroom, which is easily recognizable by its red cap with white spots. There are two prevalent theories regarding the origin of this name. The first theory suggests that pieces of the mushroom were traditionally placed in milk to attract and kill flies, hence the name 'fly agaric.'
The second theory proposes that the name derives from the mushroom's hallucinogenic properties, which could cause those who ingested it to behave in a 'fly-like' manner, buzzing with perceived flights of fancy. Both theories focus on the historical uses and effects of the fly agaric mushroom.
As part of the Phylum Basidiomycota, the Amanita muscaria is no ordinary mushroom; its spores are released through a fascinating process that requires the rearrangement of a water drop to create a force that propels the basidiospores from the gills.
The vegetative stage of these fungi consists of a mycelium, a network of branching filaments called hyphae that penetrate a substrate to obtain nutrition. This mycelium can last for incredibly long periods, and it's capable of producing the fruiting body—where the fly agaric's cap and gills form—that most people associate with mushrooms.