BRIEF DESCRIPTION: The following is largely based on the original description (Wood, 1997).

The cap of Amanita sordidogrisea is up to 50 mm wide, convex then plane, smooth, dry, dull buff to buff-gray, with a nonstriate margin.  The volva is present as scattered, flat, thin, membranous scales, distinctly paler than the cap color.

The gills are free, thin, crowded, pale cream, with a concolorous margin.  The short gills are present in at least one series.

The stem is up to 90 × 9 mm, expanding downward, white, smooth, exannulate in the only known material, without a volva or remains at the clavate base of the stem.  The base is off-white.

The spores measure (6.6-) 7.5 - 9.0 × (4.2-) 4.8 - 5.4 µm and are elongate and amyloid.  Clamps are absent at bases of basidia.

Wood describes this species as occurring in "tall open forests" from the state of New South Wales, Australia.  No potential symbionts are cited.  This species is known only from the type collection.

Since we have perceived difficulties with the assignment of section Validae of a number of Wood's species (for example, A. elongatispora) when we see an exannulate species assigned to section Validae our concerns arise again.  However, a change in placement is not so clearly required here as in other cases.  In this case despite the possibility of understanding Wood's description to the contrary, he draws an ellipsoid cell immediately below a basidium in his illustration.  Moreover the taxon lacks clamp connections, and so the argument for excluding it on the grounds of clamp connections being presented does not arise.  In addition, the basidia are of the size one would expect in section Validae.  It seems to us that the simplest line of reasoning entails placement of the species in section Validae under the assumption that in the single collection examined by Wood, the ring on the stem was lost.