The following is based on the very limited original description of this species.
The cap of A. ushuaiensis is 70 - 110 mm wide, olive-brown to gray-brown hemispheric at first, becoming
convex to planar, shiny, often with a silvery sheen, sometimes becoming strongly areolate. The flesh is firm.
The volva is present as thick, pale brown patches.
The gills are free to narrowly adnate,
moderately distant, pallid cream, with a thickened edge. The short gills
are truncate to rounded truncate, of diverse lengths, and common.
The stem is 70 - 120 × 10 - 45 mm,
narrowing upward, entirely pale
grayish white, more or less club-shaped at maturity, with longitudinal
grooves. The ring is weak and disappearing. The bulb is thick and prominent in young material, often
slightly tapered, deeply buried in substrate, sometimes splitting, and
orangish-brown or dunnish orange or pale dun-colored. The flesh is white
and rather firm. The volva is not evident in mature material.
According to Raithelhuber (1980, Metrodiana 9) the spores measure 8 - 11 × 5 - 6.5 (-7)
µm and are probably predominantly ellipsoid to elongate and are inamyloid. Clamps are probably present
at bases of basidia.
Amanita ushuaiensis occurs infrequently among mosses near Nothofagus pumilio.
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 is based on the protolog of the present species and on original research of R. E. Tulloss.
70–100 mm wide, olive-brown to gray-brown, hemispheric at first, becoming convex to planar, shiny, often with a silvery sheen, sometimes becoming strongly areolate; context firm, white; margin not described; universal veil as thick pale brown patches.
free to narrowly adnate, moderately distant, pallid cream, with thickened edge; lamellulae truncate to rounded truncate, of diverse lengths, common.
70–120 × 10–45 mm, entirely very pale grayish white, narrowing upward, more or less claviform [at maturity], surface smooth to fibrous, grooved-striate; bulb thick [and prominent in young material], often slightly tapered, deeply buried in substrate, sometimes splitting, orange-brownish or dunnish orange or pale dun-colored; context white, rather firm; partial veil tenuous and fugacious; universal veil appressed to bulb or not evident.
Odor and taste insignificant.
Occurring only among mosses near Nothofagus pumilio, infrequent.
ARGENTINA: TIERRA DEL FUEGO—Rio Grande-Ushuaia, "summer " J. Raithelhuber AR-1971 (holotype, in herb. Raithelhuber, current location unknown), 1971 J. Raithelhuber s.n.[?] ("cotype," in herb. Horak => ZT).
The "cotype" of this species comprises a single, immature specimen. It is clear from this specimen that there is no limbate or saccate volva present. The material has a proportionately large bulbous base compared to the stipe. It seems from his writings that Raithelhuber is one of those who consistently use the word "volva" to mean the basal bulb of species of Amanita that lack a limbate or saccate volva.
The nomenclatural status of the "cotype" is "original material" unmentioned in the protolog. Since Raithelhuber provided spore measurements for this species in the protolog, there must have been at least one other specimen in the holotype. ??Unfortunately, at present, the type has not been located.??
The color on the bulb in the "cotype" is still notable in the exsiccatum and appears to be the color of the exterior of the bulb, not of appressed volval material.
The stipe of the species is described quite variously by Raithelhuber in different publications. The "co-type" collection is immature with a consequently(?) squat stipe. This could explain the short stipe length given in the protolog; however, despite a longer stipe listed in later descriptions, we have not found such a collection.
The illustration on the cover of Metrodiana 14 (which is also attached to the herbarium file card for the present species in the private herbarium of Raithelhuber) may depict some other taxon—possibly not belonging in Amanita. It looks nothing at all like what one would expect from the protolog of A. ushuaiensis. This photograph shows a pale to white pileus with a portion purplish red. The pileus seems slightly powdery. On the other hand, the stipe is quite thick and appears to have a bulbous base.
No material of this taxon is presently deposited in BAFC (J. E. Wright pers. commun.).
—R. E. Tulloss
Information to support the viewer in reading the content of "technical" tabs
can be found here.
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.