Observation 99922: Amanita subsect. Limbatulae Bas
When: 2012-06-23
No herbarium specimen
0 Sequences

These were found in the Big Sandy Creek Unit.
Caps were up to 5.1 cm across and stipe up to 8.9 cm long.
Spores were white and amyloid.
Spores were relatively large and variable in length , ~ 9.1-15.1(18.8) X 5.9-7.8 microns. Q(ave.) = 1.96.
First micro photo shows the largest as well as some typical.
Need to look again through RET’s Gulf Coast list but so far no luck in finding a match. Only have a spore print as a souvenir.

Proposed Names

31% (3)
Eye3 Eyes3
Recognized by sight: In the southeastern U.S. there is a group of taxa placed by Bas in his subsection Limbatulate of Amanita sect. Lepidella. These all have a small limbate or merely marginate volva at the stem base. They are often annulate. They often have quite narrow spores…even more narrow than those in this material.
28% (1)
Recognized by sight: just to cover our potential bases here.
not seeing an appendiculate margin.

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Hi Dave, I’ll defer to Rod
By: Ron Pastorino (Ronpast)
2017-04-08 09:31:00 PDT (-0700)

on the discussion of the most correct method of measuring the spores and Q values.
In my case, I’m usually more interested in the general shape, size and ornamentation of the spores. I tend to be a little lazy about the spore measurements, usually only recording about 10 to 20 spores, but mostly always from a spore print and from more than one fb when possible. I also tend to be selective about the spores I measure, looking for ones that appear to be lined up properly and will ignore some of the extra long/large or very short/small ones as they will skew my small sample size results too much.
I seem to have the most problems of alignment with spores that are near globose to subglobose such as Amanitas in the Vaginatae group.
However, getting approximate Q values off the micro photos seems legitimate( at least for government work).

Hi Ron and Rod.
By: Dave W (Dave W)
2017-04-08 07:08:24 PDT (-0700)

To estimate Q values I usually take a paired length/width measurement and then divide. I do this with a spore photo enlarged on my computer monitor (perhaps a somewhat dubious practice…?). I generally estimate/round length/width to what I perceive to be the nearest 0.5 micron (as to claim more precision would require more rigor on my part). I also double-check a few of my Q results by sizing a small piece of paper so that the edge approximates the width of a spore and then I use this edge to estimate the multiple needed to equal length.

One thing that bothers me about recording spore dimensions, including Q, is the possibility that some spores may not align so that length and/or width is observable. That is, how does one know if a spore is positioned at an unfavorable angle?

I made all my measurements based on “divisions.”
By: R. E. Tulloss (ret)
2012-07-10 13:35:47 PDT (-0700)

So my Q values are independent of the scale. Right after I wrote the question, I realized the divisions had to be very close to equivalent to 1 micron/micrometer.

Half an hour’s work did nothing for us in terms of producing any variation in the sporograph. I did find that the Q ranged from about 1.64 to about 2.14 (with an outlyer at 2.60); and my guesstimate had been 1.66 to 2.26, which I guess wasn’t so shabby.

Anybody interested in rules of thumb for conservatively estimating average Q and range of Q from spore size range data? Does anyone regularly face this issue out there?


One division is one micron in my microscope
By: Ron Pastorino (Ronpast)
2012-07-10 13:29:09 PDT (-0700)

and they were all taken @ 1000X. Zooming in with my camera may
cause that to be a little off in the photos, but probably not significantly.

No. I didn’t skew the Q range high. [significant edit, title should have read “Q” not “W”]
By: R. E. Tulloss (ret)
2012-07-10 13:28:36 PDT (-0700)

I may not have made it quite wide enough; however that doesn’t change the general position of the sporograph based on Ron’s spore pics and measurements. After the experiment, nothing really changed.


What’s the size of one division in micrometers in the photos?
By: R. E. Tulloss (ret)
2012-07-10 13:14:55 PDT (-0700)

I assume that all the photos were taken with the same micrscope objective.

I can get Q without knowing the size of a division in the eyepiece micrometer, but I’m curious about the approximate sizes, too. I’m think that I did have my estimated Q range skewed a little bit to the high side.

Very best,


In the Limbatulae, the appendiculate margin…
By: R. E. Tulloss (ret)
2012-07-10 13:05:57 PDT (-0700)

rapidly disappears. Some of the taxa in that subsection have been placed in other sections in the past; however, they didn’t fit very well or the justifications were, um, “strained.” Some of these have now been checked genetically based on material from the herbarium here in Roosevelt; and they do seem to belong in sect. Lepidella and DON’T contain amatoxins or phallotoxins.

Hmmm. Do I have to say, “But don’t eat them because they look a hell of a lot like A. virosiformis, which does contains amatoxins, and because they could contain toxins similar to those in A. smithiana”?


Well, I said it.

Very best,


I’ve added another spore photo.
By: Ron Pastorino (Ronpast)
2012-07-10 08:43:38 PDT (-0700)

The Q range was 1.54-2.16(2.64), with the 2.64 being the long 18.8 X 7.1 micron one. The average Q would drop a little if I eliminated that particular measurement. I only measured 15 spores but there were some other rather long spores that I could see but probably more in the 2.15 range.

Maybe the longest spore in the top micropic…
By: R. E. Tulloss (ret)
2012-07-10 07:58:34 PDT (-0700)

is atypical. ??

I’m thinking maybe I was exaggerating the possible range for Q in this species (I took your average plus or minus 0.30). Maybe we should assume a lower range of Q based on the spores in the second micropic? Can you establish a Q range for me? Or maybe better, if you wrote down your measurements, could you send me a scan of those notes?


Thanks Rod, it was nice
By: Ron Pastorino (Ronpast)
2012-07-10 07:06:08 PDT (-0700)

to run into an Amanita that had such interesting spores.
Kind of wish that I had saved them.

I compared your data to all taxa for which I have data in subsect. Limbatulae.
By: R. E. Tulloss (ret)
2012-07-10 03:25:29 PDT (-0700)

After I removed all data that was not from the SE U.S., there was only one match (mutabilis) because of the breadth of the spores in your material. The material doesn’t look like mutabilis to me.

Very curious.


I tried a sporograph… [edit]
By: R. E. Tulloss (ret)
2012-07-10 03:08:04 PDT (-0700)

comparing your data to that for A. virosiformis, which was no match (the latter’s spores being much too narrow). Your material is rather large for this little species anyway.


First guesses….
By: R. E. Tulloss (ret)
2012-07-10 03:03:15 PDT (-0700)

The spores have Q too low for A. cylindrispora; however, they may be another of the several species from the SE U.S. that Dr. Bas placed in his subsect. Limbatulae of sect. Lepidella. There is also at least one (small fruiting body) member of the Phalloideae in the Gulf Coast region with very narrow spores that needs to be taken into account.

The Texas list is almost certainly not complete. Murrill’s taxa from Florida that are not on the list must also be taken into account.

Have you tried the sporograph feature that you can run from directory page for (for example) subsect. Limbatulae? You can overlay your own spore data onto the resulting compound sporograph and see what you can find out from the combined data.

Very best,


Created: 2012-07-09 22:57:43 PDT (-0700)
Last modified: 2017-04-07 16:12:28 PDT (-0700)
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