BRIEF DESCRIPTION: The cap of A. vittadinii is 75 - 170 mm wide, fleshy, from globose via hemispherical to plano-convex, white to pale dingy ochraceous, brownish at the center with age, dry, with an at first inflexed, then straight, nonsulcate, appendiculate, projecting margin. The flesh is white and unchanging or turning slightly yellowish. Pyramidal, subpyramidal, or patch-like volval remnants are present at the center, and appressed, patch- to scale-like remnants are present near the margin; the volval remnants are adnate to detersile and white to pinkish- or grayish-brownish.

The gills are rather crowded, free, rather thick, broad, attenuate, and white, cream, greenish cream, or pale greenish yellow. The short gills are abundant and truncate.

The stem is 100 - 160 x 15 - 25 mm, subcylindrical, mostly somewhat attenuate at the base, solid, white, and slightly brunnescent. Appressed to recurved, flat, membranous scales are concentrically arranged above the ring.

The spores measure (9-) 10 - 13 (-15) × (6.5-) 7.5 - 10 (-11) µm (Bas, 1969) and are broadly ellipsoid to ellipsoid and amyloid. Clamps are abundant at the bases of basidia.

Amanita vittadinii is one of the species of section Lepidella that is known to occur without accompanying woody plant symbionts. Bas (1969) established a stirps Vittadinii, a grouping that has continued to grow in subsequent years. This stirps includes the closest relatives of the present species -- currently thought to be the following: A. ameghinoi (Speg.) Singer, A. boliviana Bas nom. prov., A. bubalina Bas, A. codinae (R. Maire) Bertault, A. grallipes Bas & de Meijer, A. lilloi Singer in Singer & Digilio, A. prairiicola Peck, A. silvifuga Bas, A.singeri Bas, and A. subcaligata (A. H. Sm. & P. M. Rea) A. H. Sm. ex Tulloss (=A. salmonea Thiers).

Amanita vittadinii was also taken as type of Amanita subsection Vittadiniae Bas -- a larger grouping of taxa with what Bas (1969>) considered very primitive characters. His judgment based on morphological grounds is being born out in the results of molecular studies that show amanitas of subsection Vittadiniae at or near the base of the genus' evolutionary tree. Bas divided subsection Vittadiniae into several stirpes: Vittadinii, Nana (see A. nana) (see A. nana Singer), Nauseosa (see A. nauseosa (Wakef.) D. A. Reid), Thiersii (see A. thiersii Bas), and Hesleri (see A. hesleri Bas). Subsequently, it has appeared that one more single-species stirps may be needed in the subsection. For this stirps, I propose the name stirps Inopinata (see A. inopinata D. A. Reid & Bas).

Despite its being reported from around the world, the present species is only confirmed from Europe. -- R. E. Tulloss