Information below is derived from original research
by RET and CRC.
The cap of Amanita umbilicata is 30 - 57 mm
wide, yellow-brown over disc, grayish yellow
or light orangish yellow (4A3) toward the cap's
edge, convex to flattened-concave, with a shallow
distinct indentation in the center in all stages
of expansion, dry.
The cap's flesh is yellowish white, 2 mm thick
above stipe, unchanging, in older material
thinning to a membrane 5 - 6 mm from the cap's
Usually the cap's edge lacks radial grooves;
however, sometimes such grooves are present in age,
short (with length less than 10% of cap's radius)
in age. The volval remnants on the cap are
membranous flat irregular
patches, pale yellowish gray to yellowish gray to
grayish yellow to light grayish tan,
sometimes becoming closer to the cap's coloring
where drying has occurred.
The gills of A. umbilicata are adnate with a
decurrent line descending the top of the stem.
They are pale yellow-cream in mass and off-white in
side view, without
staining or bruising. The gills are up to 4 mm
broad at mid-length. The plentiful short gills
are unevenly distributed, of diverse lengths, and are
not squarely cut-off on the end toward the stem.
The pale yellow-white to pale yellow stem of this
species measures 42 - 72 × 2.5 -
8 mm and becomes reddish brown to
golden brown to brownish gray from handling.
The stem's bulb is
12 - 6 × 7 - 11 mm.
The stem is hollow with a central cylinder 4.0 - 4.5 mm
wide, and its is probably whitish;
sometimes the central cylinder develops a reddish
brown interior surface. The stem's membranous
to submembranous ring varies
in position between the top and the middle of the
stem and become detached and fall on to the
stem's bulb. The ring is
yellowish white to pale yellow on the upper surface
and sometimes becomes golden yellow
toward free edge; the lower surface is pale
yellowish cream. No volval remnants have been
found on the stem in the specimens that have been
The odor of this species is indistinct, but pleasant,
with older specimens having slight odor of sodium
hypochloride. Taste is lacking or faintly
like a toy balloon.
The spores of this species measure (7.0-) 7.3 - 9.4
(-10.2) × (4.8-) 4.9 - 6.1 (-6.4) μm and are
ellipsoid to elongate and amyloid. Clamps are
absent from bases of basidia.
This species is genetically separable from all other
rubescent taxa researched by the authors of this
umbilicata is known from a single, New Jersey
collection found in deep, sandy soil of Pinus
rigida-Quercus barrens.—R. E. Tulloss,
C. Rodríguez Caycedo and K. W. Hughes
Due to delays in data processing at GenBank, some accession numbers may lead to unreleased (pending) pages.
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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 based on original research of R. E. Tulloss and C. Rodríguez Caycedo.
30 - 57 mm wide, yellow-brown (5-6D5, 10YR5-6/6) over disc, grayish yellow (4B4, 10YR6-8/4) or light orangish yellow (4A3) toward margin, convex to broadly convex to plano-concave, with shallow distinct umbilicus in all stages of expansion, dry; context yellowish white, 2 mm thick above stipe, unstaining, in older material thinning to a membrane 5 - 6 mm from margin; margin nonstriate, nonappendiculate, sometimes short-striate (.05 - .1R) in age; universal veil as membranous flat irregular patches, pale yellowish gray to yellowish gray to grayish yellow to light grayish tan (10YR7-8/2-3), sometimes becoming more like pileus coloring where drying has occurred over disc.
adnate with decurrent line on stipe apex, relative
distance not recorded, pale yellow-cream in mass,
off-white in side view, without staining/bruising, 4
mm broad, broadest at mid-length; lamellulae
rounded truncate to attenuate, unevenly distributed,
of diverse lengths, plentiful.
42 - 72 × 2.5 - 8 mm, pale yellow-white to pale
yellow, from handling becoming reddish brown to
golden brown to brownish gray, narrowing upward,
flaring over notable distance at apex, decorated with
minute longitudinally oriented fibrils; bulb
12 - 6 × 7 - 11 mm, shape not recorded;
context hollow, probably whitish, not
bruising/staining, with larval tunnels concolorous,
with central cylinder 4.0 - 4.5 mm wide (rounded and
broadened at top, sometimes with reddish brown
interior surface); partial veil apical to
nearly median, membranous or submembranous,
sometimes cracking irregularly near attachment and
separating from stipe and then found on bulb
(giving impression of limbate volva), sometimes
with subdentate free edge, yellowish white to pale
yellow above, sometimes becoming golden yellow
toward free edge, with lower surface pale
yellowish cream; universal veil absent.
Odor indistinct, but pleasant, with older
specimens having slight odor of sodium
hypochloride. Taste none or faintly
like a rubber balloon.