Observation 68682: Amanita pelioma Bas

Growing alone, from soil, under a species of Quercus, in mixed, predominantly hardwood, forest

6.6cm broad
convex, white to cream, smooth dry area around center while a white powder forming “warts” or “tufts” covers the remainder of the cap.

adnate to nearly free, sub-crowded, light creamy tan?

Partial Veil:
white to off white, covering lamellae but separated from the stipe (connected at margin), membranous and covered in powdery tufts or flakes that easily wipe off.

14cm long (including rooting part of stem), Width: Apex: 1cm, Base: (forgot to measure the base)
White, covered in powder (mostly on the upper half), enlarging towards the base, soft bulb with soft pieces of white tissue, rooting (around 2-2.5cm past bulb)

strong, stale, disagreeable, if you could describe a smell as being “thick” then that would also be how I describe it
My fiancée described it as Stale Dog Breath…lol

I didn’t notice a color change at first, but after about 10 minutes I took another look and saw a slight Blue-Green stain where the KOH had been placed. One drop on the cap, one on the inside flesh of the stipe’s base and apex. The drop I placed on the base hardly had a color change, if any change at all.

Amyloid in Melzer’s Reagent


Spore, Amyloid Reaction in Melzer’s Reagent
Spores, 1000x, in Melzer’s Reagent, 1.15 microns per division
Powder from the partial veil 400x in Melzer’s Reagent
The tree that this mushroom was found under. I couldn’t get a good view of the leaves… Note the Beech tree in the back-left
I don’t know if this photo helps determine whether there are clamps at the bases of the basidia or not. I’ve never viewed clamps at the bases of basidia before so I don’t really know what I’m looking for.
I don’t know if this photo helps determine whether there are clamps at the bases of the basidia or not. I’ve never viewed clamps at the bases of basidia before so I don’t really know what I’m looking for.

Proposed Names

83% (3)
Recognized by sight: as per Rod’s determination below.

Please login to propose your own names and vote on existing names.

= Observer’s choice
= Current consensus


Add Comment
You’re welcome.
By: R. E. Tulloss (ret)
2011-06-20 01:29:08 EDT (-0400)

Very welcome.


Thank you
By: Matt Sherman (Shermanii)
2011-06-19 17:05:49 EDT (-0400)

Dr. Tulloss,
Thank you so much for taking the time to check into this!
I’m glad you were able to determine the species!
Thanks for the link as well.

Cool stuff.

nice work, Rod.
By: Debbie Viess (amanitarita)
2011-06-18 16:51:33 EDT (-0400)

thanks for all your behind-the-scene efforts. I do NOT have your patience! ;)

The best match for the spores…takes us back to Amanita pelioma…
By: R. E. Tulloss (ret)
2011-06-17 15:35:03 EDT (-0400)


I measured 20 spores and got a very non-normal distribution just as you did. In terms of spore length, it was wild. It ranged from 10.4 μm to 22.5 μm! Because the spores were very oddly shaped in many cases (apex very narrow compared to the remainder of the spore), it was hard to find spores that were properly positioned to be measured. I always record the super large and (if I see any) super small spores in order to get the highest and lowest possible maxima and minima to report in my overall ranges…even when the super large spore is not part of my 20 officially measured spores.

In this case my spore data was (10.4-) 10.5 – 17.3 (-22.5) x (7.2-) 7.3 – 10.1 (-11.8) μm, (bold_L = 12.3 μm; bold_W = 8.1 μm; Q = 1.40 – 1.65 (-1.99); bold_Q = 1.51), hyaline, colorless, smooth, thin-walled, amyloid, ellipsoid to (occasionally) elongate, adaxially flattened, often narrowing toward apex, with giant spores present; apiculus sublateral, cylindric; contents dominantly monoguttulate, with or without addtional small granules; color in deposit you know.

The universal veil remains in a thin layer on the cap. It is mostly small cells with less plentiful filamentous hyphae. The cap has a well defined pileipellis. I searched for clamps, but not extensively and didn’t find any.

I went to the ?subsection+Solitariae page and ordered up the combined sporograph for that subsection. I then removed all taxa that are not known from the region including Canada south through Costa Rica. I then removed all remaining taxa that have a persistent, membranous partial veil. I then removed all taxa for which the sporograph had only minimal overlap with the sporograph for your material.

I was really quite surprised at what was left when I finished: Amanita pelioma — back at my first guess based on your photo and the color change that you reported. Even though your material has such unusual spores, the match is quite striking.

Because Bas placed A. pelioma in his stirps Cinereoconia, I’m going to put up the definition of that stirpes on the WAO site…even though it was not something scheduled to be done for some time. I thought it might be of interest to you. See the green column on the right of this page:


Very best,


Material arrived…
By: R. E. Tulloss (ret)
2011-06-16 21:58:14 EDT (-0400)


I received today the part of this collection that you sent me. Thank you.


Amanita tephrea?
By: R. E. Tulloss (ret)
2011-06-09 12:14:43 EDT (-0400)

The new posting < http://www.mushroomobserver.org/68794 > brought to mind the possibility that this could be A. tephrea. Could you send me a pie-shaped piece of the cap with some well-dried gills on it? My address is on the “about the editors” page on WAO.

Very best,


Well that’s all OK, but…
By: R. E. Tulloss (ret)
2011-06-07 16:22:54 EDT (-0400)

The powdery volva and the rooting base are clues that I got distracted from thinking about.

Bas’ taxonomy of Lepidella ia about clamps, spores, and very, very much about the structure of the volva.

So it makes sense to make a list of things with powdery volvas and rooting stems and then sort through the possibilities with the aid of Matt’s spore data. Debbie put forward A. longipes and noted that it has a slight and not unpleasant odor. And we can add that its spores have Q values that are > 2.0 more than half the time. So I think we can say that longipes is probably out.

Amanita chlorinosma doesn’t have a radicating base and its spores are smaller than the ones that Matt measured.

So Amanita rhopalopus (maybe?) or Amanita magniradix (maybe? but the spores aren’t narrow enough) or what else comes to mind?

Did the surface of the cap project out beyond the ends of the gills? I can’t really tell in the picture with the cap cut in half…


I doubt that Alan’s picture is of A. pelioma, but the color staining is the same…
By: R. E. Tulloss (ret)
2011-06-07 15:51:42 EDT (-0400)

I have no certainty about an ID of Matt’s material in this observation.

The spore data has a significant number of length measurements at the lowest measureed length, if the method of selecting spores to measure is random (for example: Start in the upper left hand corner. Move your view downward until a spore in correct view for measurement is found. Measure it. Never move to the left. Repeat. Move down with some movement to right permitted until you have to reverse and move up. Never move to the left. Following a path like this you won’t measure the same spore twice, amd the question of which spore to measure next is dependent on chance. This should produce twenty spores with length distribution pretty close to a bell-shaped (normal) distribution curve. If it doesn’t produce data with that property, then you have to understand the cause. Maybe…. The material is immature or is too old or was dried badly or has had all the best spores eaten by mold or the specimen was diseased or you didn’t follow your “randomizing rules” or you it took too long between the time the specimen was collected and the time the spore print was collected (and the mushroom dehydrated and couldn’t make full size spores) or ……

I sent the distribution chart in XLS and PDF forms this time. At least the PDF ought to do the job. With Matt’s eyepiece micrometer, it looks like he can distinguish distances of a little over 0.5 microns. (It’s not exactly 0.5 microns because sometimes his adjacent length measurements are separated by 0.5 microns and sometimes by 0.6 microns because of the rounding he has to do when he multiplies the number of divisions by the distance represented by a single division.)

Imagine the lengths arranged so that all the measurements of the same length are listed in the same column. You’d have a column for lengths of 10.4 microns,
another for lengths of 10.9 microns, another for 11.5 micorns, 12.1, 12.7, 13.2, 13.8, and 14.4 microns…given Matt’s data. There are 8 columns, A randome distribution would show a large lump of the data in the 4th and/or 5th columns (roughly speaking) and the amount of data in a column (roughly speaking) should diminish as you move toward the first or toward the last column. Their should be a “middle” of the data and the amount of data should diminish in a roughly symmetrical way going from that “middle” toward the ends of our little data display.

That doesn’t happen in Matt’s data. Below are the columns (measurement values) with the number of items in each column:

10.4… 10.9… 11.5… 12.1… 12.7… 13.2… 13.8… 14.4
… 5………. 2………. 2………. 4………. 5………. 1………. 0………. 1

The data quantities are shifted to the low end of the scale.

That’s the observation. Something caused this distirbution. It might be useful to Matt to know that this kind of distribution can sometimes tell a story.


if the spore drop doesn’t match and the base doesn’t turn blue-green…
By: Debbie Viess (amanitarita)
2011-06-07 13:12:25 EDT (-0400)

can it really be pelioma? the over-all gestalt and color do seem to match.

Like Matt, i thought that spore drop indicated that the spores WERE mature.

Alan Rockefeller has a beautiful example of pelioma here on MO with a strikingly blue-green base to its stipe:


Should KOH even cause a color change? And what about that odd odor?

By: Matt Sherman (Shermanii)
2011-06-07 12:41:24 EDT (-0400)

I have a mac and it wont let me open the spreadsheet you sent.
However, I do believe that I can open a Microsoft Excel file. (but not 100% sure about that)

The spores I measured were from the spore print. I thought this was the best way to find mature spores…but I will measure 20 more spores from an area closer to the stipe if you think I’ll get better results.

I went back to the same spot that this observation was found and saw another one growing. I photographed and collected it and will create an observation for it either tonight or tomorrow then I can compare the data between the two specimens and maybe that will give us a little more to work with.

The mushroom did not bruise blue-green to the touch nor was the color change very strong. It bruised brown where I handled the stipe while carrying it back to the house.

Spreadsheet on its way to you by email
By: R. E. Tulloss (ret)
2011-06-06 23:03:34 EDT (-0400)


After checking the sporograph, I thought maybe your spore data would not fit the typical “bell curve” of a normal distribution. It didn’t. I sent an email with the spore data arranged in columns by spore length. It has an explanatory note on the spreadsheet itself. I did the spreadsheet with Open Office (latest version). If you have a problem, I can resave the file in Excel format.

I think you may very well have a slightly immature specimen of A. pelioma. Try measuring the spores from a spot on a gill rather close to the stem…anyway closer than the spot you sampled last time. The spores mature first nearest to the stem. A sampling of more mature spores might create a better fit with “canonical” pelioma sporograph. I discuss this in the material I sent. Feel free to share as much of it as seems worth sharing.

Very best,


Bluegreen bruising
By: R. E. Tulloss (ret)
2011-06-06 22:32:14 EDT (-0400)

If the color change was produced chemically, but could have been produced mechanically or in the passage of time, there is only one North American candidate — Amanita pelioma Bas. I’d suggest that you check your spore data against that of A. pelioma using the User_sporograph page on WAO.

And the gills of pelioma are what I call “cafe au lait” and the whole fruiting body is on the grayish cream side of white…very noticeably so.

I’m going to try the sporograph myself out of curiosity.


By: walt sturgeon (Mycowalt)
2011-06-06 17:39:30 EDT (-0400)

Long in the tooth is an expression that refers to old horses and people.

Never heard that one before :]
By: Matt Sherman (Shermanii)
2011-06-06 15:30:34 EDT (-0400)

It did not seem to be getting old to me.

Something I left out of the notes:
The rooting part of the stem was a little longer than what I dug up. (if that helps anyone at all)

By: Debbie Viess (amanitarita)
2011-06-06 15:17:11 EDT (-0400)

“long in the tooth” is just another way to say old.

By: Matt Sherman (Shermanii)
2011-06-06 15:09:54 EDT (-0400)

I’m sorry, I do not know what you mean by getting long in the tooth or gills.
Do you mind explaining?

Spore Sizes and Q
By: Matt Sherman (Shermanii)
2011-06-06 14:57:26 EDT (-0400)

10.4-13.2 (-14.4) x (6.9-) 7.5-9.2 (-10.4) microns

20 Spores were measured at 1000x (1.15 microns per division).
Amyloid in Melzer’s Reagent

Length x Width
11.5 × 8.1
10.9 × 7.5
12.7 × 8.1
10.4 × 8.1
10.4 × 8.1
12.7 × 8.1
12.7 × 8.1
12.7 × 8.6
12.1 × 8.1
11.5 × 8.1
12.1 × 8.1
10.4 × 7.5
12.1 × 8.1
12.1 × 8.1
10.4 × 7.5
13.2 × 9.2
10.4 × 6.9
12.7 × 8.1
14.4 × 10.4
10.9 × 7.5

11.8 × 8.1 microns
1.42, 1.45, 1.57, 1.28, 1.28, 1.57, 1.57, 1.48, 1.49, 1.42, 1.49, 1.39, 1.49, 1.49, 1.39, 1.44, 1.51, 1.48, 1.38, 1.45

Range of Q:
(If any numbers seem wrong feel free to correct me.)

the dog-legged stipe (it’s dog-theme day!) of your lepidella…
By: Debbie Viess (amanitarita)
2011-06-06 14:48:03 EDT (-0400)

reminds me of A. longipes, but that one doesn’t usually have a bad odor. Was your amanita getting a bit long in the tooth (gills)? Any old amanita can smell bad.

SE lepidellas are challenging to ID!

Created: 2011-06-06 13:03:07 EDT (-0400)
Last modified: 2011-06-20 09:45:37 EDT (-0400)
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