The genus that includes both the fly agaric and the death cap mushrooms is Amanita.
The fly agaric is Amanita muscaria, recognized for its red cap and white warts. The death cap is Amanita phalloides, a dangerously poisonous species whose amatoxins can cause severe liver damage. Although their appearances and effects differ, both belong to the same genus.
Amanita contains roughly 600 described species worldwide. The genus includes edible mushrooms, psychoactive species, and some of the deadliest fungi known. This mixture is why visual identification alone is unsafe: harmless-looking Amanita species can resemble lethal relatives, while rain or age may alter identifying features such as cap color and veil remnants.
A common mix-up is confusing a genus with a species. Amanita is the broader taxonomic group; muscaria and phalloides are individual species within it. The name fly agaric refers specifically to A. muscaria, while death cap refers primarily to A. phalloides and related species in some regions.