The following description is based on the original description by Nagasawa and Hongo
The cap of A. hamadae is 45 - 70
mm wide, yellowish-brown to brown or olive-brown over the center, grayish
yellow towards the margin in maturity, light yellow to yellow around the margin when
young, campanulate at first, then becoming convex to planar with a
subviscid when moist, with a strongly sulcate-striate margin. The
flesh is thin, white, yellow under the cap skin.
The gills are free, subcrowded, 4 - 7 mm
broad, whitish, becoming somewhat pinkish with age, with a yellow
subflocculose edge. The short gills are truncate.
The stem is 100 - 130 × 4 - 10 mm,
slightly tapering upward, hollow, sulfur yellow to light yellow or
grayish yellow, except for the lower third which is tinged with salmon
color, and fibrillose-scaly except for its bottom-most portion [Note:
illustration shows decoration is in a pattern often called zebroid, flame,
or snakeskin.]. A bulb and ring are absent in the original collection. The saccate volva is 20 - 40 × 15 - 20 mm, membranous,
attached only at the very base of the stem, with a light yellow tint in
the upper part of the limb, and with a fringed internal limb. The flesh is thin, white, yellow under the skin, pinkish at the base of the stem.
Odor and taste are indistinct.
The spores measure 10 - 12 (-13) × (7-) 7.5 - 9 (-11) µm and are broadly ellipsoid to ellipsoid and inamyloid. Clamps
are absent at bases of basidia.
This species occurs alone or in groups in association with Abies-Castanopsis forests, especially under A.
firma and was originally described from western Japan.
While the colors, spore shape, and habit of
the present species suggest a relationship to the Slender Caesars
this relationship can be questioned because this species lacks a ring and
lacks clamps throughout the fruiting body including the basidia. In
addition, assuming that the illustration of the basidia and subhymenium is
correct, the subhymenium is not composed of layers of roughly globose
cells as it is in stirps Hemibapha.
Among the known taxa of stirps Hemibapha having spores
approximately equally distributed between broadly ellipsoid and ellipsoid,
Amanita hamadae is the only species known without bright colors.
The original description of A. hamadae includes brief mention of a gelatinized suprapellis
(upper layer of cap skin) including hyphae with yellow content. We are not
sure how to interpret this statement; but, if this describes a gelatinized matrix
through which ungelatinized colored hyphae run, then we should point to a group of taxa with a
similar cap skin that has a tropical distribution and includes A.
sampajensis A. V. Sathe & S. M. Kulk., A.
flammeola Pegler & Pierce, and A.
dunicola Guzmán. It is also possible that the hyphae
observed in the suprapellis of A. hamadae are vascular hyphae
[hyphae with refractive content that rarely have cross-walls (septa)] or are not part of the
Amanita but of an attacking mold.—R. E. Tulloss and L. Possiel
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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 is derived from the protolog of the present taxon.
from protolog: 45 - 70 mm broad, at first light yellow (2A5) to yellow (2A6-7), then grayish yellow (4C6-7, 3B6-7, 2B7), over disc yellowish brown (5D6-7) to brown (6D7, 6E7-8) to olive brown (4D8), campanulate to convex later expanding to planar, markedly umbonate, subviscid when wet, glabrous; context thin, white, yellow under pileipellis; margin conspicuously sulcate-striate:.
from protolog: free, subcrowded, whitish, becoming somewhat pinkish with age, 4 - 7 mm broad, with edge yellos and suflocculose; lamellulae truncate.
from protolog: 100 - 130 × 4 - 10 mm, sulphur yellow (1A5) to light yellow (2B5) or grayish yellow (2B6), tinted with moderate salmon (4A3, 5A2-3) in lower half to one-third, with lower one-quarter to one-third glabrous (per figure), above minutely fibrillose-scaly creating snake-skin or zebroid patterning (per figure), slightly narrowing upward; context hollow, white, pinkish at base of stipe; exannulate; universal veil as saccate volva, membranous, 20 - 40 × 15 - 20 mm, with light yellow (1A4-5) tint in upper part, attached only at very base of stipe, with distinct "fringed" limbus internus.
from protolog: Odor and Taste indistinct.
from protolog: as cutis, up to 400 μm thick, in two layers; suprapellis gelatinized, 50 - 75 μm thick; [subpellis presumably ungelatinized;] filamentous hyphae 3 - 7.5 (-10) μm wide; vascular hyphae ca. 3 μm wide, with yellow contents, especially noted in suprapellis.
from protolog: 50 - 65 × ca. 12.5 μm, 4-sterigmate; clamps absent.
from protolog: On pileus: absent. On stipe: filamentous hyphae 3 - 7.5 μm wide; inflated cells scattered, subglobose to oblong to ellipsoid, up to 100 × 30 (-50) μm.
lamella edge tissue
from protolog: inflated cells subglobose, mostly 15 - 35 μm wide, thin-walled, hyaline, in chains.
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.