Cap 7-14 cm broad, convex, expanding to nearly plane; margin inrolled, becoming incurved to decurved, often with adhering veil fragments; surface moist, covered with large, firmly attached, angular warts; cap color white, the warts at times cream-buff to buff-brown in age or from handling; context up to 2 cm thick, firm, white, unchanging; odor mild when young, unpleasant and strong in age; taste mild.
Gills free to narrowly attached, close, moderately broad, white, to cream, fimbriate, not forked, lamellulae up to 3-seried.
Stipe 6-12 cm long, up to 4 cm thick, solid, fleshy, the base typically bulbous with a root-like extension; surface white, dry, striate at the apex, cottony-floccose below, sometimes buff-brown in age or from handling; partial veil membranous, thin, fragile, either leaving fragments on the young cap or forming an evanescent, short-limbed annulus; volva consisting of one to several scaly rings which in age may disappear.
Spores 9-11.5 x 6-8 µm, ovoid, thin-walled, hilar appendage occasionally prominent, amyloid; spore print white.
Solitary to scattered under pines, e.g. Bishop pine (Pinus muricata), and Monterey pine (Pinus radiata); fruiting from mid to late winter.
Unknown, to be avoided.
This large, white Amanita has massive cap warts that mimic those of the Sierran puffball Calvatia sculpta. Also unusual is a rooted, bulbous stipe base, often with scaly rings. Amanita cokeri is similar but somewhat smaller. Like Amanita magniverrucata, the cap has firmly attached warts, but these are typically less impressive. In addition, the stipe base generally lacks the scaly volva rings of Amanita magniverrucata. Neither of these pine-dwelling species is common.