description is based on the original description by Guzmán and Ramírez-Guillén
The cap of A. yema is (50-) 80 - 140 (-190) mm wide, blood red to red-brown, red in the center, shading
gradually to crimson red, orange red, orange yellow at the margin, sometimes unevenly colored with orange-red spots
in older specimens, ovoid to globose when young, convex to
plano-convex, sometimes slightly umbonate with age, sometimes with a
roughened or tomentose center, viscid when moist, shiny when dry, with
modertate or short striate margin. The volva is
absent or present as a large, irregular, thick, white patch. The flesh is
white, red below the cap skin.
The gills are touch the stem, pale yellowish white
to yellow, with a concolorous and subfloccose edge. Short gills are not described, but are probably truncate.
The stem is (65-) 125 - 180 (-220) × 15 - 25 (-40) mm, white to pale yellowish white or yellow, orange-yellow
towards the base, sometimes with brownish or reddish staining after
handling, hollow or stuffed with cottony white fibers. The ring is membranous,
skirt-like, thick, yellow or orange-yellow or pinkish yellow, striate on the upper surface,
floccose-scaly below. The volva is saccate, white, membranous, up to 5 mm thick, with two or more irregular
lobes, smooth inside, with a short white internal limb, roughened or somewhat scaly outside colored by
the substrate. The flesh is white, yellowish in the stem skin.
The odor and taste are mild but pleasant.
The spores measure (9-) 10 - 13 (-16) × (6-) 7 - 8 (-10) µm and are broadly ellipsoid to elongate and inamyloid.
Clamps are present at bases of basidia.
Amanita yema was originally described from
central Mexico where it is reported from a large number of localities.
This species is known from coast to coast in central Mexico in association with
pine-oak (Pinus-Quercus)and pine (Pinus) forests.
This species grows solitarily or in small groups.
The authors separate A. yema and A.
tecomate only by a difference in spore size. The spore shapes
are in fact essentially identical. The arguments given for the separation
are not convincing to us. The two "species" are said to be
commonly sold in a mixture in public markets. On the available
evidence, RET believes the two names refer to a single species and selects
the name A. yema to apply to it.
According to the original description A. yema can be assigned to Amanita stirps Caesarea and is
strikingly similar to Amanita basii Guzmán & Ramírez-Guillén
and A. laurae Guzmán & Ramírez-Guillén, which were described in the same
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.
Due to delays in data processing at GenBank, some accession numbers may lead to unreleased (pending) pages.
These pages will eventually be made live, so try again later.
A. yema and A. tecomate (both)—XAL
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 species (Guzmán and Ramírez-Guillén 2001).
from protolog: [-/-/-] (9-) 10 - 13 (-16) × (6-) 7 - 8 (-10) μm, (est. Q = 1.43 - 1.62; Q' = 1.53), hyaline, inamyloid, ellipsoid to elongate, at least frequently adaxially flattened (per figure); apiculus sublateral, "small"; contents not reported; white in deposit. [Note: A conservatively estimated range of Q is provided so that an approximate sporograph can be generated. Spore ranges were presented with multiple larger dimensions in parentheses instead of the single upper limit of observed size that is standard on this site. We present here the largest of the authors' values as the upper limits of length and width.—ed.]
from protolog: .
from protolog: MÉXICO: VERACRUZ EDO.—Mpio. Xico- eastern Cofre de Perote, S. of Tembladeras, ca. El Rosario, El Revolcadero, 11.viii.1983 Villarreal 533 (holotype, XAL).
from protolog of A. tecomate: MÉXICO: VERACRUZ EDO.—Mpio. Xalapa - old Xalapa to Coatepec rd., SE of Jardín Botánico Francisco J. Clavijero, Ejido Bentio Juárez, 7.vii.1983 Chacón 1123-A (holotype of Amanita tecomate, XAL).
—R. E. Tulloss
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Guzmán & Ram.-Guill.
The original description of this species is
difficult to interpret for numerous reasons among which are, for example,
failure to identify methodology for examination of spores and microscopic
anatomy, failure to make correct counts of the layers of cells in the
subhymenium, failure to make drawings from well-hydrated sections, misuse
of common terminology, failure to indicate the full range of variation for
dimensions and shapes of microscopic features, failure to segregate the
stipe surface from remnants of the internal limb that decorate it, etc. -- R. E. Tulloss and L. Possiel
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.