Amanita vaginata

Common Name: Grisette
Description: cap 5-9 cm across, oval then convex expanding to almost flat with an umbo and a distinctly lined margin; grayish brown, darker toward the disc, lighter toward margin, smooth and sticky when moist. Stem 65-120 by 4-14 mm high and wide.
Habitat: singly or in groups on the ground or in grass in open, mixed coniferous and deciduous woods. Common. Found widely distributed throughout North America.
Edible: Yes.

Source: Mushrooms of North America by Roger Phillips.