The Stalk is 5-20 cm (2-7"), has a ring and a bulbous base with rows of cottony patches. It is 1-3 cm (1/4 - 1 1/4") in diameter at the base, narrowing slightly towards the cap. The stalk is white to cream colored; smooth to somewhat scaly.
The Universal Veil which causes the white spots on the cap also often forms concentric circles (usually 2-4) on the lower stalk at the top of the bulb. Additionally, a membranous Partial Veil usually forms a thin, persistent, median to superior, skirtlike ring on the stalk.
Gills are free or slightly attached, crowded, broad, whitish.
Spore Print is white. Spores are 9-13 x 6.5-9 microns, broadly elliptical, smooth, colorless, and nonamyloid.
On the ground, under pine, spruce, fir, birch, live oak and madrone. They grow solitary, scattered, densely, or in large rings in forests and at their edges. Often found in coastal pine forests and along freeways where pines have been planted.
Common in Western North America, Europe, and Asia.
In N. America these fruit from July - October; Fall to early spring in California.
Named the Fly Agaric because of it's use, when mixed with milk, as a method of killing houseflies. Its color may fade drastically with age, especially in direct sunlight or after a soaking rain.