BRIEF DESCRIPTION: The following is based on the description by Curreli (2000).

The cap of A. heterochroma is 80 - 150 mm wide, fleshy, yellow-greenish tone when young, light brown out from the center, entirely brown at maturity, at first globose, sometimes with slight depression when fully expanded, viscid in humid weather, usually with a smooth margin, Marginal striations appear rarely in mature material, and then only faintly. The volva is present as plentiful warts that are ash-gray. The flesh is white and firm.

The gills are free, rather crowded, narrow markedly toward the stem, at first white, then cream-yellowish ochraceous, with a finely floccose edge. The short gills are truncate and of diverse lengths.

The stem is 100 - 180 × 15 - 25 mm, cylindric or slightly narrowing upward, smooth, white and smooth above the ring, ash gray becoming brown at maturity below the ring. The bulb is turnip-shaped, is more or less rooting, and has a point at the bottom. The ring is white, fragile, may be lost or remain only as a small fragment. The volva is friable, ash-gray, and forms numerous rings around the bottom of the stem and top of the bulb. The flesh is white and firm.

The spores measure (8-) 9.5 - 15 (-22) × 6.7 - 8.2 µm and are ellipsoid to elongate and inamyloid. Clamps are rather numerous at bases of basidia. Neville and Poumarat (2004) report that the type of the present species is immature and lacks spores. Based on other material they report the following: (8.5-) 9 - 11 (-11.5) × (6-) 6.5 - 7.5 (-8) µm and are ellipsoid, rarely elongate and inamyloid.

This species occurs in association with Eucalyptus camaldulensis and Cistus monspeliensis in sandy-gravelly soil. It is only  from Sardinia (Italy). We agree with Neville and Poumarat that it is possible this species was introduced to Europe from Australia with Eucalyptus. On the other hand, the apparent close relationship to Amanita muscaria (L. : Fr.) Lam. suggest it may have evolved from a common Eurasian ancestor.

The reader should compare the present species with Amanita gioiosa S. Curreli ex S. Curreli since the two taxa appear in the same habitat.