BRIEF DESCRIPTION: Amanita magnivolvata is a very large species. In the photograph of dried material, the immature specimen on the left is 145 mm tall.  Unfortunately, there is apparently no data concerning the dimensions of the material when fresh.  Surely, it was a record-breaker.

The cap of A. magnivolvata is 80 - 115 mm wide, hemispheric when young, dry, glossy, with a sulcate margin (25% of the radius); the cap is gray with slight olive tinge; there is a faint deeper gray ring on the inner edge of sulcations. The cap becomes leather brown on drying. Remnants of the volva are usually absent on caps of mature specimens; however, occasionally, scattered membranous patches are present.

The gills are free, cream colored or whitish, drying pale tan, with edges white and conspicuously flocculose, 3 - 4 mm or more broad, thick. The short gills are unevenly distributed, of varying lengths, and truncate (?).

The stem is 95 - 125 x 15 - 20 mm, whitish, with tomentum of slightly sticky hyphae, finely striate at apex, exannulate, firmly stuffed, stuffing collapsing upon drying and developing transverse fissures. The saccate volva is membranous, ample (up to 107 x 62 mm dried!), with felty and smooth surface, pure white when collected, after handling developing small rusty yellow spots on exterior, which persist after drying.

The spores measure and are (9.0-) 9.8 - 15.0 (-17.7) x (7.2-) 8.4 - 12.2 (-15.6) µm inamyloid and subglobose to broadly ellipsoid (occasionally ellipsoid or globose). Clamps are relatively common to common at bases of basidia.

This species was originally described from Finland. It also occurs in Norway and as far south as the Mediterranean region. Its range appears limited to Europe.

The species has been reported from mixed forest with Aspen, Birch, and Spruce forest of the Scandinavian peninsula. Italian material is reported in association with Oak.

This species is most closely associated with a Northern Hemisphere group of very large species ("Great Ringless Amanitas"): A. pachycolea D. E. Stuntz in Thiers & Ammirati, A. pachyvolvata (Bon) Krieglst., and A. violettae Tulloss. -- R. E. Tulloss