This description is based on the original description of Murrill (1941) and type study by David T. Jenkins (1979).
The cap of Amanita fraterna is up to 20 - 40 mm wide, plano-convex, viscid, honey colored with a rather dark brown center, with a nonstriate margin. The volval remnants are present as a few, randomly distributed, floccose patches. The flesh is thin and white.
The gills are free, crowded, broad, white, with minutely decorated edges.
The stem is 60 - 70 × 5 - 8 mm, cylindric, pinkish-tan, with floccose patches on the top of the bulb and lower stem. The ring is white, membranous, superior (20 mm from the top of the stem), and persistent. The stem's bulb is small. The volva is fragile.
Odor and taste were not reported for this mushroom.
The spores measure 7.8 - 8.6 × 5.5 - 5.9 µm and are ellipsoid and weakly amyloid. Clamps are absent at bases of basidia.
This species was originally described from Florida, U.S.A. under oak.
The editors of this site owe a great debt to Dr. Cornelis Bas
whose famous cigar box files of Amanita nomenclatural information
gathered over three or more decades were made available to RET for computerization
and make up the lion's share of the nomenclatural information presented on this site.
The following text may make multiple use of each data field.
The field may contain magenta text presenting data from a type study
and/or revision of other original material cited in the protolog of the present taxon.
Macroscopic descriptions in magenta are a combination of data from the protolog and
additional observations made on the exiccata during revision of the cited original
The same field may also contain black text, which is data from a revision of the present
taxon (including non-type material and/or material not cited in the protolog).
Paragraphs of black text will be labeled if further subdivision of
this text is appropriate.
Olive text indicates a specimen that has not been
thoroughly examined (for example, for microscopic details) and marks other places in the text
where data is missing or uncertain.
The following material not directly from the protolog of the present taxon and not cited as the work of another researcher is based on original research by R. E. Tulloss.
from protolog: 20 - 40 mm wide, "dull melleous with subfuligineous disc," viscid; context thin, white; margin nonstriate; universal veil as scattered fragments.
from protolog: free, crowded, white, broad, with edges fimbriate; lamellulae not described.
from protolog: 60 - 70 × 5 - 8 mm [length probably includes bulb], whitish, cylindric above bulb, floccose; bulb small; context "rosy isabelline throughout"; partial veil superior, attached about 20 mm below apex, white, membranous, persistent; universal veil "fragile."
from type study of Jenkins (1979): [-/-/1]
7.8 - 8.6 × 5.5 - 5.9 μm, (Q = 1.32 - 1.56; Q' = 1.46),
hyaline, thin-walled, weakly amyloid, ellipsoid, often adaxially flattened; apiculus sublateral, short, truncate-conic; contents guttulate;
color in deposit not recorded.
from type study of Jenkins (1979):
U. S. A.: FLORIDA—Alachua Co. - Gainesville, 7.vi.1938 W. A. Murrill F 16376 (holotype, FLAS).
[Note: A second collection is mentioned in the protolog—Gainesville, 8.vi.1938 W. A. Murrill F 16377 (paratype, FLAS).]
It is possible that A. sp-F14 and/or A. sp-N47 may be identifiable with the present species.
—R. E. Tulloss
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can be found here.
Each spore data set is intended to comprise a set of measurements from a single specimen made by a single observer;
and explanations prepared for this site talk about specimen-observer pairs associated with each data set.
Combining more data into a single data set is non-optimal because it obscures observer differences
(which may be valuable for instructional purposes, for example) and may obscure instances in which
a single collection inadvertently contains a mixture of taxa.