The following description is based on Jenkins (1984).
The cap of Amanita radiata is up to 70 mm wide, plano-convex to planar, brown slightly striate margin.
The volval remnants are present as moderately thick, whitish, floccose-membranous patches in the center. The flesh
is white, 7 mm thick over the stem.
The gills are adnexed, moderately crowded, narrow, white; the short gills are moderately abundant and attenuate.
The stem is 45 - 60 × 10 -13 mm, tapering upward, slightly expanded at the top, solid, fibrillose to
fibrillose-scaly, whitish with brownish fibers, with a very slight floccose-membranous rim on the bulb,
breaking into patches. The ring is apical, easily lost, white. The basal bulb is oval, 40 × 25 mm wide.
This species has no odor or taste.
The spores measure 8.6 - 10.2 × 3.9 - 5.5 µm and are elongate to cylindric and amyloid. Clamps are absent
at bases of basidia.
Originally described from Alabama, USA under Loblolly Pine.
In his discussion of this species, Jenkins (1984)
says that he had difficulty placing it to section in the genus Amanita
because the pigmented cap is reminiscent of caps in section Validae
whereas the narrow spores and easily lost ring are characters he
associated with section Lepidella. Amanita media
Dav. T. Jenkins is another species which he found difficult to place for the same
reasons. Based on recent molecular studies, it appears that section Validae
has ancestors that fall outside section Lepidella in the current
taxonomic scheme of Amanita. This suggests that any group of
ancestors of a species in section Validae will probably include
ancestors in Lepidella but must include younger ancestors that we
would recognize today as belonging in a different section. As molecular
studies advance, this view may change; however, at the moment, perhaps
it is wise to seek further with regard to arguments for sectional
placements for so-called "borderline" species. For example, in
the present case the fact that the subhymenium is not cellular in A.
radiata could argue against placement in section Validae.
When I had trouble deciding on placement of A.
salmonescens Tulloss, Dr. Bas advised me that the cellular hymenium could be a
factor supporting placement in section Validae. Obviously, further
work on the three taxa named in these notes is necessary.—R. E. Tulloss
Jenkins (1984): Alabama: Under Pinus taeda (Loblolly Pine) and Quercus.
ALABAMA—Covington Co. - btwn. Florala and Opp, U.S. Hwy. 331 rest area, 11.vi.1981 Jeannie and David Jenkins 1642 (holotype, in herb. Dav. T. Jenkins, Univ. Alabama, Birmingham). Shelby Co. - Oak Mtn. St. Pk., NE of Pelham, 9.vii.1982 David T. Jenkins 1736 (paratype, in herb. Dav. T. Jenkins, Univ. Alabama, Birmingham).
—R. E. Tulloss
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