Amanita albocreata

This is a key to gilled mushrooms, that is, mushrooms having a definite cap with a fertile surface consisting of gills. The fruiting body usually also has a stem, although that may be lateral or absent (usually, then, the mushroom is growing from wood). You can use this key to identify mushrooms that you find.

Fruiting body containing fibers (usually in the stalk)

Fruiting body having a combination of some of the following characteristics:
Stalk growing out of a cup of cottony tissue called a volva (all white-spored mushrooms with a volva go here)
Cap with scattered patches or flakes of the same sort of tissue as the volva (see second picture), easily peeled off
Annulus (skirt-like ring on stalk)

All yellow-capped Amanitas can go here
All Amanitas with concentric, toothed rings around the base of stalk definitely go here
No volva; basal bulb sometimes small, often rimmed in one way or another
Universal veil generally leaves remains on cap as small scattered patches

Basal bulb rimmed by a peronate universal veil, creating an effect that is often compared to a sock rolled down at the top
Cap typically white to greyish brown

Cap up to 5" across; white overall, often yellow, brown or tan over the disk

Amanita albocreata     (G. F. Atkinson) E. J. Gilbert