BRIEF DESCRIPTION: The following is based on the original description of Miller (1992).

The fruiting bodies of this species grows deeply inserted in sandy soils--with only the cap showing above the surface.  The cap of Amanita brunneiphylla is 45 - 85 mm wide, broadly convex to nearly plane in age, dry, dull white, with a nonstriate and appendiculate margin.  The cap is covered with numerous soft, low, white, cottony volval warts over the center, diminishing toward the cap margin.  The volva also comes off easily on the fingers.  The flesh is white.

The gills are subdistant, broad in the center, nearly free, light brown, and darker brown with age.  The short gills are of diverse lengths and common.

The stem is 105 - 140 × 13 - 21 mm, dull white, with mealy patches of volva at the base.  The bulb is a tapering fusiform bulb, 40 - 60 × 25 - 36 mm.  The flesh is white, tinted gray in the base.

The spores measure (8-) 9 - 10.8 × 4.1 - 5 µm and are elongate to cylindric and strongly amyloid.  Clamps are absent at bases of basidia.  In deposit, the spores have an unusual pale yellow color.

Originally described from the state of Western Australia in association with open stands of Eucalyptus and Allocasuarina growing in deep sandy soil.

In Amanita, elongate bulbs, narrow spores, and fruiting bodies deeply inserted in the soil are often associated with "leaky" ecosystems (Tulloss 2005).

Café au lait lamellae are known from North American taxa such as A. microlepis Bas and A. pelioma Bas.  However, the American species have little else in common with A. brunneiphylla.

Miller reports one of the paratype specimens to have had yellow tint which suggests that this species may be subject to the yellowing syndrome that has been noticed in species of section Lepidella from all over the world.  (See Amanita subsolitaria (Murrill) Murrill.)