The cap of Amanita
flavescens is 40 - 90 mm wide, nonappendiculate,
with a margin having striations extending 20 to 70% of
the radius (although most are near the shorter extreme);
it is sometimes rather pale at first, but becomes buff
yellow to orangish cream to between beige and orangish
cream, with thin flesh. In wounds there is a tendency to
ochraceous staining. The flesh is white to whitish. The
volva is absent or present as a smooth white patch or
The gills are adnate by a line,
white to pale orangish cream in side view, and close to
crowded. The short gills are truncate to rounded
truncate, common to plentiful, of diverse lengths, and
The stem is 75 - 120 × 9-
- 13 mm, white, subcylindric or narrowing upward, and
exannulate. Its flesh is off-white. The saccate volva is
membranous, white, and adhering to the stem base.
The spores measure (8.4-) 89.0 -
12.6 (-17.6) × (7.4-) 8.0 - 10.6 (-14.1) µm and are
globose to subglobose to broadly ellipsoid to
(infrequently) ellipsoid and inamyloid. Clamps are not
observed at bases of basidia.
Amanita flavescens is
known from Sweden and Norway and very similar material
has been collected on the Island of Newfoundland, Canada.
Given this latter fact, material from Greenland reported as
A. crocea (Quél. in Bourd.) Singer ex
Singer should be re-examined because of the possibility that it could
be A. flavescens. Amanita flavescens has not
been well understood until its type was recently studied
and fresh material was collected. For example, prior to
1999, many north European collections were determined as A. crocea.
The most similar taxa are those closely related to A. crocea (link above). The
recently described A. ochraceopallida Contu
seems to differ very little from A. flavescens.—R. E. Tulloss
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 is based upon
original research by R. E. Tulloss.
40 - 50 mm wide, Buff Yellow (2.5Y 8.0/7.0); context thin; margin striate [quite short in exsiccata—(0.1R - 0.15R)], nonappendiculate; universal veil absent.
narrowly adnate by line, not very crowded, with edge of varying form; lamellulae truncate to rounded truncate, common, of diverse lengths, unevenly distributed.
75 - 100 mm long, white, subcylindric or slightly narrowing upward; context not described; exannulate; universal veil as saccate volva, membranous, white, adhering to stipe base only (up to one quarter of limb height in exsiccata), having two to four lobes sometimes of very different heights, with interior surface in exsiccata roughly concolorous with pileus as opposed to buff to buffy cream or sordid cream exterior surface, with limb reaching up to nearly half of stipe length.
with suprapellis of partially gelatinized to gelatinized hyphae colorless and 35 - 60 µm thick, with subpellis of ungelatinized elements orangish yellow and 125 - 175 µm thick; overall 170 - 235 µm thick, exuding yellow pigment in 20% NH4OH; filamentous, undifferentiated hyphae 2.4 - 6.4 µm wide, branching, interwoven, with some having yellowish subrefractive walls; vascular hyphae 3.2 - 19.2 µm wide, branching, sinuous, occasionally tangling locally, scattered to locally common.
RET additions: Suprapellis may be minimal. Vascular hyphae sometimes narrower near pileus margin (e.g., 2.4 - 6.0 μm wide), slightly sordid brownish yellow to orange-brown to sordid yellow.
largely collapsed; filamentous, undifferentiated hyphae 2.4 - 8.0 µm wide, branching, plentiful, interwoven in open lattice, usually fasciculate, occasionally with yellowish subrefractive walls; acrophysalides clavate, thin-walled, up to 89 × 24 µm and probably larger; vascular hyphae not observed.
bilateral; wcs = 30 - 40 µm; subhymenial base comprising divergent intercalary cells [ovoid to clavate, up to 35 × 16.8 µm, thin-walled, scattered, some overlapping subhymenium (but not giving rise to basidia), some not arising from central stratum] and plentiful, frequently branching, filamentous, undifferentiated hyphae (often with branches parallel to central stratum), with angle of divergence very variable from shallow to nearly perpendicular to central stratum; central stratum including partially inflated intercalary segments (e.g., fusiform, 87 × 14.0 µm); filamentous, undifferentiated hyphae 2.0 - 9.0 µm wide, branching; terminal, divergent inflated cells not observed; vascular hyphae 3.2 - 6.4 µm wide, sinuous, common
wst-near = 40 - 50 µm; wst-far = 65 - 80 µm; sometimes pseudoparenchymatous locally, often including hyphal segments running parallel to central stratum, with basidia arising from sides and ends of uninflated hyphal segments and occasionally from inflated cells.
40 - 69 × 10.5 - 15.8 µm, dominantly 4-sterigmate (even in apparently immature basidiome), rarely 1-sterigmate, with sterigmata up to 8.9 × 2.3+ µm; clamps not observed.
On pileus: absent. On stipe base, exterior surface: filamentous, undifferentiated hyphae 1.9 - 14.4 µm wide, most under 6.0 µm wide, branching, dominantly in fascicles, but also singly, many with sublongitudinal orientation, densely packed, ungelatinized to partially gelatinized, sometimes with yellowish walls; vascular hyphae not observed. On stipe base, interior: filamentous, undifferentiated hyphae 1.6 - 8.0 µm wide, branching, dominating, dominantly in fascicles, occasionally singly, interwoven in open lattice, occasionally with yellowish walls, sometimes constricted at septa, with tip cells occasionally slightly expanded; inflated cells clavate to broadly clavate to ovoid, not plentiful, scattered, up to 50 × 37 µm, with walls sometimes slightly thickened; vascular hyphae up to 17.6 µm wide, scarce. On stipe base, inner surface: partially gelatinized, comprising entirely yellowish filamentous, undifferentiated hyphae.
RET additions: Inflated cells of interior layer may be larger than reported for the type (e.g., 63 × 17.5 μm and 65 × 65 μm) with walls thickened up to 0.8 μm. The inner surface layer of the saccate volva may be scant or present only in limited areas and appear stretched with hyphae not strongly vertically aligned (like strings of filled string bag).
longitudinally acrophysalidic; filamentous, undifferentiated hyphae 2.7 - 10.6 µm wide, branching, plentiful, often with yellowish walls; acrophysalides plentiful, up to 154 × 45 µm, often broad and rounded at base, thin-walled; vascular hyphae 3.5 - 8.0 µm wide, infrequent.
absent in sect. Vaginatae.
absent in sect. Vaginatae.
lamella edge tissue
region dominated by filamentous, undifferentiated hyphae (even in rather immature basidiocarp); inflated cells somewhat sparsely distributed, clavate to pyriform to subglobose, usually not forming distinct layers, in rare regions of more plentiful cells up to 5 layers present.
RET additions: sterile; in younger material with inflated cells in 5 - 6 layers, readily collapsing, detersile, subpyriform to subclavate (e.g., 27 - 45 × 19.0 - 25 μm), with filamentous hyphae tending to become dominant.
[60/3/1] (8.4-) 8.6 - 11.6 (-13.6) × (7.4-) 8.2 - 10.5 (-12.6) µm, (L = 9.6 - 10.7 µm; L’ = 10.2 µm; W = 8.6 - 9.6 µm; W’ = 9.1 µm; Q = (1.02-) 1.04 - 1.24 (-1.35); Q = 1.12 - 1.14; Q’ = 1.13), hyaline, colorless, smooth, thin-walled, inamyloid, globose to subglobose to broadly ellipsoid to (infrequently) ellipsoid, adaxially flattened; apiculus sublateral, cylindric to truncate-conic; contents granular to mono- or multiguttulate; color in deposit not known.
composite for all material revised by RET: [168/9/4] (8.4-) 9.4 - 12.5 (-17.6) × (7.4-) 8.2 - 10.5 (-14.1) µm, (L = 9.6 - 11.5 µm;
L’ = 10.7 µm; W = 8.6 - 9.9 µm; W’ = 9.3 µm; Q = (1.02-) 1.05 - 1.25 (-1.58); Q = 1.11 - 1.20; Q’ = 1.14), hyaline, colorless, smooth, thin-walled, inamyloid, globose to subglobose to broadly ellipsoid to (infrequently) ellipsoid, adaxially flattened; apiculus sublateral, cylindric to truncate-conic; contents granular to mono- or multiguttulate; color in deposit not known.
Sweden: In lawn under Betula in plantation of frondose trees.
Norway: At 350 - 750 m elev. In ravine landscape with remnants of natural Alnus forest or in calcarious soil of mixed forest in small scale agricultural landscape or in Picea forest or "in alpine zone."
NORWAY: AKERSHUS—Ås -
Åsmosan, 2.viii.1984 Gro Gulden 16/84 (O).
Lindåskroken [UTMWGS84 NM 35,01-02],
21.viii.1999 P. Marstad, H. Myhre, T. Torjesen s.n.
[Tulloss 8-21-99-E] (O; RET 310-7); Efteløt
prestegård [UTMWGS84 NM 455,012-013]
20.viii.1999 L. Winter, S. Aasrum, M. Nuñez s.n.
[Tulloss 8-20-99-C] (O; RET 308-10, nrITS seq'd.).
NORDLAND—Saltdal, near Belvatnet [2128 I
WQ 4430, 750 m], 28.viii.1988 Jens Stordal 25605
[32 V NN 020 460, 870 m], 26.vii.1981 Jens Stordal
Upsala, Slottsbacken, ca. Gunnar Wennerberg Monument,
22.vii-3.viii.1936 S. Lundell & K. G. Ridelius
[Fung. Exsicc. Suecici No 308 as "Amanitopsis
adnata (W. G. Smith apud Saunders &
Smith) Sacc."] (holotype, PC).
—R. E. Tulloss
Information to support the viewer in reading the content of "technical" tabs
can be found here.
(E.-J. Gilbert & S. Lund.) Contu
"False Saffron Ringless Amanita"
1. Amanita flavescens, Norway.
Jens Stordal - (1) Norway, courtesy of Dr. Gro Gulden (O).
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.