BRIEF DESCRIPTION: The cap of Amanita breckonii is 40 - 90 mm wide, with color ranging from pale yellowish white to pale yellowish tan (for example, Light Buff to Naples Yellow when young and Ochraceous Buff to Cinnamon Buff when older*), convex to globose when young, becoming convex to broadly convex to plane to irregular in maturity, subviscid to viscid, with a decurved margin when young and strongly tuberculate-striate margin at maturity. The volval remnants are present as flat, irregular shaped,  whitish to light buff, floccose plaques or patches.

Gills are adnate to adnexed then free, white, close to subdistant to occasionally crowded, thin, and narrowly ventricose. The short gills are present in several tiers.

The stem of this species is 70 - 100 × 9 - 20 mm, narrowing upward, solid or stuffed, white, smooth and glabrous at first, becoming finely furfuraceous towards the base. The bulb is large, solid, sometimes without marked separation from the remainder of the stem, sometimes distinctly marginate, subglobose to pear-shaped. A short, sharp "false root" is present at the bottom of the bulb. The ring is basal to subbasal, rarely median, often appearing double (see discussion, below). The volva is present as a white, friable, low rim of tissue around the top of the bulb, often with fragments adhering to the surrounding soil, disappearing with age. The flesh is white.

The odor and taste are mild.

The spores measure (7.2-) 9.8 - 12.8 (-16.0) × (4.5-) 6.2 - 8.7 (-10.8) µm and are ellipsoid to elongate and inamyloid. Clamps are present at bases of basidia.