Observation 117797: Amanita sect. Phalloideae (Fr.) Singer

When: 2012-09-07

Collection location: Deep River County Park, Hobart, Indiana, USA [Click for map]

0.0° 0.0°

Who: Danielle B. (dbly)

No specimen available

-Single specimen growing alone in soil in a black oak savanna
-Stipe/stem was hollow
-Volva was damaged as it was removed from the soil. It was not swollen or scaly, but more like a sheath.
-Lamellae present

Proposed Names

27% (1)
Recognized by sight: volva and annulus present, pale white gills

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Another new page on WAO under development. [edited again and again]
By: R. E. Tulloss (ret)
2012-11-28 22:14:45 SAST (+0200)

Another new page that is related to the discussion here is


You can compose the URL by adding www.amanitaceae.org in front of the above.

For some reason, MO software won’t let me make a complete URL in this case.

Very best,


This is probably not new to you, but…
By: R. E. Tulloss (ret)
2012-11-28 18:35:30 SAST (+0200)

I’ve added a “Basics of Spore Measurement” teaching topic to all the taxon pages on WAO.


Thank you for your response.
By: R. E. Tulloss (ret)
2012-11-27 15:44:41 SAST (+0200)

I think that we can increase the benefit from our discussion if I put together a teaching topic on spore measurement for the WAO site.

I would be glad if you would watch this development and let me know if it runs into any problems in your view.

I’ll let you know where the page will be located.

What I hope to do is provide a methodological guide with supportive reasoning.

Very best,


measuring spores
By: Danielle B. (dbly)
2012-11-27 08:00:09 SAST (+0200)

I do not measure spores from a photograph. I meant that I take pictures of the spores under the microscope with a camera for the confirmation of the shape of the spore, not to measure the size. In class we had calibrated the scopes using an inserted eye piece with measurements and calculated the units into microns. On all of my collections I try to use the spore print and if that did not work I use the gill. I also always work under 100x oil immersion objective with a 10x eyepiece so 1000x total. We were told to try and include the biggest and smallest spore in our data for the range. Hope that clears some of it up.

Another “Teaching Topic”
By: R. E. Tulloss (ret)
2012-11-27 00:57:47 SAST (+0200)

“Biometric variables: meanings & how to define a range” is another one.


When I see only a small number of different lengths or widths,
By: R. E. Tulloss (ret)
2012-11-27 00:55:30 SAST (+0200)

my first thought is that the level of magnification may be low and/or the smallest divisions on the eyepiece micrometer may be too large to capture the amount of variation that occurs in amanita spores.

Another symptom of this situation is the bimodal distribution of spore length. About half of your spores have one length and about half have another spore length. Only the largest spore doesn’t fall into one of the two length-defined groups. A random sample with small enough divisions in the eye piece micrometer and measurement with an oil-immersion lens (1000x or higher) should produce a normal distribution of (e.g.) length…represented by something close to the typical bell-shaped curve.

You are the second person in the last few days to mention to me that they measure spores from photographs. If you are measuring large numbers of spores, and need to randomize the process so that your spores are more likely to represent the distribution of sizes and shapes found on gills and/or spore prints of a given taxon, it must be rather difficult to do that with photographs.

Another practical choice that results in bimodal distribution of spore length is the concept that measurement should be carried out by reporting the closest marking on the eyepiece micrometer rather than estimating the distance between the markings on the eyepiece micrometer and reported the estimated overall spore lengths. In general, the latter is actually more accurate.

If you’d like to continue a discussion on these sorts of things off-line, I’d be glad to do so.

On the taxon pages of the www.amanitaceae.org website, there are "Teaching Topics’ on the upper left of all pages. You may find the topic called “Rounding metric values” of interest. Another that may be of interest is called “Spore shape and length/width ratio (Q).”

There’s another one that I’ll have to look up….

Senior moment.


By: Danielle B. (dbly)
2012-11-26 01:45:57 SAST (+0200)

Thank you so much!! I will have to look into that website.

I did keep the spore measurements I tried to find the a few of the largest and smallest spores that I could along with the others below they are typed as (length/width) all are in micrometers. I am still sorting out spore pictures from my other collections and once I find this one’s picture I will post it.

1. 11.62/5.81
2. 11.62/4.98
3. 11.62/4.98
4. 11.62/5.81
5. 12.45/5.81
6. 12.45/4.98
7. 12.45/4.98
8. 12.45/4.98
9. 11.62/4.98
10. 13.28/4.98

Amanita virosiformis might be another possibility, but I have never seen it as…
By: R. E. Tulloss (ret)
2012-11-24 22:45:55 SAST (+0200)

large as is your specimen.


The spore measurements should be helpful.
By: R. E. Tulloss (ret)
2012-11-24 22:36:44 SAST (+0200)

Have you ever tired the ?User+sporograph page here?


Did you keep your actual set of spore measurements?

The widths and probable Q (length/width) would seem eliminate the one long-limbed species in sect. Lepidella (A. cylindrispora).

Considering the shape of the spores and the size of the volval limb piece in your next to last photograph, I’d check:

Amanita peckiana in sect. Amidella

Amanita canadensis thought to be in sect. Amidella

One of the narrower spored species in sect. Phalloideae.

I just added some basic information about he ?User+sporograph page among the “teaching topics” that are near the upper left corner of species pages on

< www.amanitaceae.org >.

I hope that might be of some use to you.

Very best,


By: Danielle B. (dbly)
2012-11-24 21:30:49 SAST (+0200)

Thanks so much

I just put a picture of the cap up again, it must not of loaded properly before. Anyways I had marked in my notes that the cap surface and cap margin was smooth and non striated. Also, the spores I had measured ranged from 11.62-13.28 micrometers in length and 4.98-5.81 micrometers in width. The spore shape was amygdaliform (sort of like an almond) and the hilar appendage was connected slightly off center from the base.

By: R. E. Tulloss (ret)
2012-11-24 17:41:21 SAST (+0200)

Did you happen to get a picture of the cap from above?

Without the view from above to see whether or not the cap edge is striate, I checked the short gills of which you depict many. A few of the shorter ones are distinctly truncate (squarely cut off) while others narrow more slowly and smoothly (are attenuate). This kind of mixture of short gill shapes can be seen in several sections. One of these is section Amidella; however, I see no reddish brown staining on the stem surface; and there is a persistent (although thin) partial veil. Hence, I think section__Amidella__ is less likely (although, perhaps, A. peckiana would remain a possibility). Because sections Vaginatae and Caesareae have plentiful truncate short gills, I think those sections could be set aside (from the present evidence); and, then, since Amidella is also unlikely, the margin of the cap probably wasn’t striate.

This leaves us with section Phalloideae which, of course, has a limbate volva encircling the stem base.

There is no certainty here, but I’d suggest section Phalloideae.

Very best,


Created: 2012-11-24 09:43:51 SAST (+0200)
Last modified: 2013-11-15 00:30:17 SAST (+0200)
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