Amanita yema

The following description is based on the original description by Guzmán and Ramírez-Guillén (2001)

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 publication.

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 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

[ Keys & Checklists ]
[ Draft description of, & key to, sect. Caesareae ]

[ Keys & Checklists ]
[ Draft description of, & key to, sect. Caesareae ]