BRIEF DESCRIPTION: Amanita atkinsoniana has a cap up to 125 mm wide; it is white to whitish, becoming red-brown in wounds.  The more or less pyramidal warts are pale gray at first, then brownish gray to mouse gray, tending to reddish brown with age.

The gills are free, cream-white, and crowded; the short gills are "usually attenuate" according to Jenkins (1986).

The stipe may be up to 100 x 20 mm excluding the bulb; it is whitish and decorated with brownish gray floccose material at least in the upper half.  The partial veil forms a skirt that may fall away entirely or remain and turn slimy and yellowish at maturity (see photo).  The universal veil on the stipe base is quite unusual in Amanita because it forms warts that extend nearly to the very bottom of the bulb.

The spores measure (8.0-) 8.5 - 10.5 (-13.0) x (5.9-) 6.0 - 7.7 (-8.5) µm and are broadly ellipsoid to ellipsoid to elongate and amyloid.  Clamps are present at bases of basidia.

Amanita atkinsoniana is associated with oak and pine and, probably, other related tree genera.

The species has a range in eastern North America extending from southern Quebec south at least to the state of Michoacan in Mexico.

Bas (1969) assigned this species to his stirps Microlepis. -- R. E. Tulloss