The following is based on the description of Bas (1969). All
flesh is white at first and becomes yellow when the fruiting body is cut or broken.
The cap of Amanita lutescens is 35 - 60 mm wide, convex then
plano-convex or plane, finally slightly concave, gray, dry, with a nonsulcate, appendiculate margin. The cap is
densely covered with very small, darker, brownish gray, pulverulent-subflocculose warts.
The gills are rather distant, narrowly adnate to free, rather broad (5 - 8
mm), and pale cream. The short gills are rounded-attenuate to attenuate.
The stem is 35 - 70 × 4 - 8 mm, subcylindrical, and solid. It is white and striate
above the annulus and gray and puverulent-flocculose to pulverulent-squamulose. The annulus is superior and
membranous, white and striate on the upper side, and grayish flocculose on the lower side. The stipe bears a
small globose bulb.
The fruiting body has a strong odor and a mild taste.
The spores measure (7.5-) 8 - 10 (-10.5) × (5.0-) 5.5 - 7.0 (-7.5) µm and are
amyloid and broadly ellipsoid to ellipsoid. Clamps are absent at bases of basidia.
Amanita lutescens was described from Japan.
Bas placed the present species in
his stirps Cinereoconia (see A. cinereoconia G. F. Atk. var. cinereoconia).
Bas felt that the present species was not closely related to A. griseofarinosa Hongo
of the same stirps because of its broader spores, more or less pulverulent layer of volva on the
cap, and a more friable annulus. Because of my experience with yellowing taxa in North America that appear to be
"diseased" specimens of other taxa (see
A. subolitaria (Murrill) Murrill). Note that such specimens often have their
spore shape distorted. I am inclined to be suspicious that A. lutescens may prove to be synonymous
with A. griseofarinosa. After all, A. cinereoconia itself has both pulverulent and warted
volval remnants on the pileus according to environmental circumstances. Moreover, the fact that Bas proposed a
yellowing variety of A. cinereoconia might be taken as suggesting that taxa of stirps Cinereoconia
are liable to the "yellowing syndrome." On the page for A. cinereoconia, I discuss a recent collection
of that species that indeed seemed normal at first, but developed the yellowing syndrome.
—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.
Imazeki and Hongo. 1987. Color. Illus. Mushr. Japan 1: 130, pl. 32 (fig. 224).
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 Dr. Z. L. Yang or another researcher is based upon original research by R. E. Tulloss.
NOTE: Spore measurements from papers by Z. L. Yang use his "Times New Roman" face for "Q"
and "Q'"—respectively, "Q" and "Q.
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.