Technical description not yet available.

BRIEF DESCRIPTION: The cap of Amanita magniverrucata is 60 - 156 mm wide, white to whitish at first, and darkens slightly when bruised. Its surface has a dry dull appearance until senility (because material exposed "between volval warts" is either more volva or pileus flesh); it may be moist to subviscid in senility. It appears to lack a distinct cuticle. The cap is 8 - 30 mm thick above the stem, and the flesh is white and unchanging when cut or bruised. The margin is strongly incurved to inrolled at first, decurved at maturity, and often strongly appendiculate (with flocculence from the volva and with substantial pieces of the weak annulus).

At first the volva is thick and rather smooth, covering the entire pileus; it then becomes areolate and becomes divided into conspicuous warts as follows: pyramidal, large over disc and much of pileus at first, smaller or absent toward margins (even at first), fleshy, with faces longitudinally striatulate, further stretching and flattened or breaking up with further pileus expansion, white to tan to light brown, becoming darker brown to reddish brown on tips (or sometimes in their entirety), up to 20 mm wide at base and 10 mm high, adnate until age (but rather easily broken, leaving irregular scar on remaining universal veil tissue), completely detersile in senility.

The gills of this species are narrowly adnate or shallowly notched at first, becoming free, with a decurrent line on the top of the stem at least until loss of the annular material, subdistant to crowded, white to off-white to pale ivory to pale buff, with a fimbriate margin, often with annulus remnants attached, broadest at about 75% of distance from stipe to pileus margin. The short gills are subattenuate, unevenly distributed, of diverse lengths, and plentiful.

The stem is 28 - 120 × 10 - 34 mm, white to whitish, often with brown to reddish brown to buff stains, cylindric to subcylindric or narrowing upward, dry, glabrous above the annulus, and appressed fibrillose to flocculose below. The stem has a bulb, 35 - 105 × 18 - 60 mm, that is carrot-shaped or turnip-shaped at first. The bulb often exhibits shallow vertical splitting in its upper half and is often doglegged. The annulus is apical to superior, and will eventually break and tear and (subsequently) be lost or collapse. The annulus is white, submembranous to subfelted to floccose-fibrillose, with plentiful soft white cottony patches on the underside. The volva takes the form of scattered warts on the stem below the annulus and one to 11 or more irregular to concentric rings (entire or comprising scales or warts) on the uppermost part of the bulb and on the lower stipe. It is colored as on the piles and often disappears with age.

The odor of this species is indistinct at first; but, later, it is strong and unpleasant. The taste is reported to be mild.

The spores measure (6.5-) 7.8 - 12.5 (-15.0) × (4.5-) 5.2 - 7.5 (-8.6) µm and are ellipsoid to elongate (rarely broadly ellipsoid or cylindric or bacilliform) and amyloid. Clamps are infrequently found on bases of basidia.

The warts of this species are directly connected to the cap flesh without a well-formed pileipellis between them. This anatomy has misled people into thinking the "pileipellis" is composed of vertically oriented chains of cells when what they have seen is the lower part of the very thick warts (left photo shows "button" stage in development of the mushroom). In senility, the cap gelatinizes/decays, especially when wet (right photo); then the warts can be washed off or otherwise removed.

Amanita magniverrucata occurs in California, U.S.A. and Baja California, Mexico. It occurs with Live Oak for the most part, but conifers or madrone (Arbutus) may be present. -- R. E. Tulloss

Photos: R. E. Tulloss (top and center-left, California); Ron Pastorino (center-right and bottom, California).

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Last change 29 October 2005.
This page is maintained by R. E. Tulloss.
Copyright 2003, 2004, 2005 by Rodham E. Tulloss.
Photographs copyright 2003 by Rodham E. Tulloss.
Photographs copyright 2005 by Ron Pastorino.