3. Amanita sp-amerirubescens07, note dark volval remnants of unknown origin/cause on immature specimens, Oneida Co., New York, U.S.A. (RET 598-1)
This page is in early development and is based on a taxon which was first recognized on genetic grounds. We caution against using a picture to identify this mushroom. At present, we do not know which characters are determined by the mushrooms genes and which might be determined by other factors.
For the time being, any new descriptive information will be placed on the technical tab of this page first.
No odor or taste has been reported for this mushroom.
[Note: Spores from the specimens with blackening
volva are not included here as they may have been
altered by environmental factors, such as a
"disease" of the fruiting body. They tended to
have greater width and, hence, lower Q values than
the spores reported above.—RET]
Singly or in small group. New York: In sandy soil of mixed woods with Acer, Fagus, Quercus, Pinus, & Tsuga canadensis. Pennsylvania: At 523 m elev. In dark loam of woods including Tsuga canadensis.
U.S.A.: NEW YORK—Oneida
Co. - unkn. loc., 3.x.2013 Eric Smith s.n.
(RET 598-1, nrITS & nrLSU seq'd.).
PENNSYLVANIA—Lackawanna Co. - Lackawanna
St. For., Thornhurst [41.2006° N/ 75.6025° W, ca.
525 m], 4.vii.2013 David Wasilewski s.n.
(RET 550-7, nrITS & nrLSU seq'd.).
Monroe Co. - Pocono Mtns. [41.1271° N/ 75.4907° W,
514 m], 19.vii.2015 D. Wasilewski s.n.
(RET 709-6, nrITS & nrLSU seq'd.).
Apparently there is a "darkening volva syndrome" that attacks members of the rubescent group in section Validae. Since the universal veil on the stipe bulb of RET 550-7 is pallid and the pileus has opened and separated from the partial veil, we have an example of undarkened universal veil in mature or near mature material. The fact that the volval warts on immature caps of RET 598-1 are dark suggests that an alien agent may be the cause of the pigmentation. Historically, dark-volvas on amanitas have occasionally been attributable to invasion of the volval tissue by a dark-walled hyphomycete—as has been reported for Amanita muscaria.
The blackened volva of RET 598-1 was examined at 1250× in dilute KOH without stain. While a dark-walled hyphomycete was seen, it was seen only in a single fragment in the section examined. It had walls about 0.5 μm thick and frequent, perforated septa about 0.8 μm thick. The source of the dark appearance seems to be much more likely to be necropigment in the collapsed, gelatinized, and partially decayed cells of the upper surface of the volval warts. These cells (both filamentous hyphae and inflated cells) contain pigment (saturated orange-brown) that is significantly darker than the rest of the tissue which is dominated by colorless to very pale brown, transparent inflated cells.
In comparison to the warts of RET 550-7, the darkened warts are much thinner and seem to have lost material to decay; the latter's dark upper surface is irregular and not smooth as in the undarkened warts. Further indication that the original surface has been lost in the darkened warts is provided by the absence of soil particles or other detritus on their surfaces.
There appears to be some hope that spore size and
shape can play a role in morphological segregation
of the eastern North American, rubescent
group. We must wait until the spore sample
sizes for the various taxa all increase.
30 June 2019
The nrITS and nrLSU sequences of the present
species appear to
be identical to those of the white- or pale grayish
white-capped provisional species
—R. E. Tulloss and K. W. Hughes
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can be found here.
1. Amanita sp-amerirubescens07, note pallid volval remnants on top of bulb in material with separated partial veil, Lackawanna St. For., Lackawanna Co., Pennsylvania, U.S.A. (RET 550-7)
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.