Destroying Angel is the common name used for three other related Amanita mushrooms, all equally deadly. The Amanita ocreata, Amanita verna, and Amanita bisporigera are also known by this nickname. All are white, but may discolor with age, and posses the typical Amanita trademarks, a partial veil and a visible volva. A veil on a mushroom is a thin tissue that originally covers the gills, but breaks as the mushroom matures to allow the spores to escape. There may be remnants of the veil left on the cap, or on the stem (forming what is called an annulus or ring). The volva is the sack-like structure at the base of the mushroom that the stem emerges from. All Amanitas have a volva, and as many Amanitas are poisonous, some amateur mushroom pickers (myself included) avoid fungi with a volva.
These mushrooms are commonly found under oaks and other hardwoods in much of the western United States. A. ocreata is very common in southern California and has been responsible for several deaths recently, most notably several starving illegal aliens who ate the mushroom out of desperation.