BRIEF DESCRIPTION: The orange-brown to brownish yellow cap of A. arkansana measures up to 150 or more mm wide and has a strongly striate margin.

The gills are free (sometimes with a decurrent line, close to crowded, and fade from pale yellow to creamy white and (eventually) white as the mushroom ages.

Its stem is up to 175 x 30 mm or larger and is pallid, with pale yellow remains of a felted extension of the internal volval limb distributed below the white annulus.   This latter stipe decoration becomes a deeper yellow or orange from handling.   A white, membranous, saccate volva encloses the stipe base.

The spores measure (7.0-) 7.7 - 11.4 (-15.0) x (5.6-) 6.0 - 8.0 (-10.2) µm and are broadly ellipsoid to ellipsoid (rarely subglobose or cylindric) and inamyloid.  Clamps are present at bases of basidia.

Amanita arkansana is easily distinguished from Amanita jacksonii Pomerleau by its white lamellae, pallid stipe, and orange-brown pileus.  Also, A. arkansana often forms larger and very fragile fruiting bodies.   Amanita garabitoana Tulloss, Halling & G. M. Muell. is a Central American species related to A. arkansana.  A Mexican species with narrower spores and yellower cap than A. garabitoana has recently been named A. hyalyuy Arora & G. H. Shephard.  Amanita banningiana Tulloss nom. prov. is a smaller species, with a cap at first bright yellow, becoming orange-brown from the center outward through development; its stem is yellow with subfelted yellow fragments of the part of the volva originally present between the ring and the stem's surface in the developing "button."

Amanita arkansana was originally described from the state for which it is named and occurs throughout the southeastern U.S.A.   It is associated with pine and oak.
-- R. E. Tulloss