BRIEF DESCRIPTION: The following is based on the description of Beeli (1935) to which has been added data from Bas (1969) and from recent collections, etc.

The cap of A. pulverulenta is 100 - 110 mm wide, white, thick and fleshy, convex to plano-convex, and with a non-striate, appendiculate margin.  The flesh of the cap is white.

The gills are free, attenuate at both ends, white or light yellowish, 10 mm broad.

The stipe is 130 x 15 mm, subcylindric to cylindric, sometimes narrowing upward; and the base is somewhat thickened and rooting.  The context is white with a tendency to pinken with cutting or bruising and solid or partly stuffed.  There is a superior, membranous, white annulus that is often ephemeral according to Beeli (however, his illustration (from the collector's watercolor) shows a mature or nearly mature specimen with an annulus still well-formed, much as in the photo, above.  The volva on the stipe base forms light rings.

The spores [from a few recent collections from Zambia] measure (9.0-) 10.0 - 12.3 (-12.7) x (5.5-) 5.6 - 7.0 (-7.4) µm and are elongate and amyloid.  [Bas ( 1969) reports spore measurements from the holotype collection as follows: (10-) 10.5 - 12 (-13.5) x (4.5-) 5 - 6.5 µm. These spores were elongate to cylindric.]  Clamps are absent from bases of basidia.

This species was described from the Republic of Congo and is known from central Africa.

For comparison, see A. boudieri Barla, A. polypyramis (Berk. & Ccurt.) Sacc., and Amanita gracilior Bas ex Bas & Honrubia.

Based on microscopic examination of the type, Bas (1969) felt that A. pulverulenta was synonymous with the taxon now called A. boudieri Barla; however, our examination of recently collected material indicates the taxa are distinct.  We find that spore measurements on the new material are consistent with those Bas made on the type collection, and the presence of a persistent annulus (not seen by Bas) is consistent with Mme. Goossens' watercolor of the type collection as reproduced by Beeli. -- R. E. Tulloss & David Arora