Observation 97078: Amanita murrilliana Singer
When: 2012-06-11
Herbarium specimen reported

Notes: (10.2) 11.0 – 13.0 (13.1) x (6.5) 7.3 – 8.1 (8.4) [17/1/1]
spore avg. = 11.9 × 7.6

Proposed Names

29% (1)
Recognized by sight
-30% (2)
Recognized by sight
Used references
Based on microscopic features

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Updated my votes.
By: R. E. Tulloss (ret)
2012-06-12 16:16:59 CDT (-0400)

Based on the spore data, sporograph, stipe based section, original images, etc., I think that the evidence for A. murrilliana being the ID has gotten to be very good.


sporograph added.
By: Richard and Danielle Kneal (bloodworm)
2012-06-12 15:55:49 CDT (-0400)
17 spores were measured.
By: Richard and Danielle Kneal (bloodworm)
2012-06-12 15:49:35 CDT (-0400)

updated observation.
i will work on calculating the Q range.

Thank you, again. [extensively edited]
By: R. E. Tulloss (ret)
2012-06-12 08:39:10 CDT (-0400)

Thanks for the sectioned stipe base. It looks as though the stipe is attached to the volval sac on the sides as well as at the stipe’s very bottom. This is a characteristic of A. murrilliana, which is shared by very few other taxa in section Caesareae so far as I know. Unfortunately, we know very little about the somewhat mysterious A. cokeriana.

[edits follow]

How many spores did you measure? When you post spore measurements, it would be very helpful to me if you added at least two things.

(1) The information on the number of spores measured, which Dr. Yang and I give in the following format: “[n/s/c]” in which “n” is the number of spores measured; “s” is the number of individual specimens (mushrooms) from which the spores were measured; and “c” is the number of collections from which these mushrooms came. I ordinarily measure 20 or more spores per specimen (a larger number when the number of specimens is very small).

(2) For each spore calculate a value of Q (=length of spore/width of spore; for example, 11.0/7.3 = 1.51, round to just two decimal places); and give a range of Q values. The description of how to prepare a range is given on every technical tab of the WAO site.

With a range of length and width (as you have given) and a range of Q, you can then generate a sporograph from your data. On the www.amanitaceae.org?User+sporograph page, you can enter the data and get a sporograph. You can also overlay your sporograph with sporographs from the tecnnical tabs of the WAO site. I’m going to email you such a figure based on Q values that I guesstimated from your length/width data.

Very best,


sectioned stipe base added.
By: Richard and Danielle Kneal (bloodworm)
2012-06-11 23:56:50 CDT (-0400)
You’re welcome. [edit]
By: R. E. Tulloss (ret)
2012-06-11 23:20:27 CDT (-0400)

You asked a key question.

[edit] Did you happen to get a shot of the sectioned stipe base?


will do.
By: Richard and Danielle Kneal (bloodworm)
2012-06-11 23:13:47 CDT (-0400)

thanks again for the help.

Since Murrill may have confused A. murrilliana and A. cokeriana,
By: R. E. Tulloss (ret)
2012-06-11 23:07:58 CDT (-0400)

it is espeically worthwhile to check the spores on this one.

Here’s the other link:



Good question.
By: R. E. Tulloss (ret)
2012-06-11 23:04:45 CDT (-0400)

I had taken that to be a splitting of the surface layer of the stipe; however, in the first image, that is clearly not the case. It is a true ring. Hence, the problem is reduced. The only thing that I know of that would fit the set of images is A. murrilliana (due to cap colors, ring color, placement in sect. Caesareae, etc.). You should check the spore measurements, and see if you get a match.

Thanks for making me take a closer look.

Very best,


By: Richard and Danielle Kneal (bloodworm)
2012-06-11 22:21:15 CDT (-0400)

what do you make of the ring on the stipe?

Make a longitudinal section if you have the fresh material.
By: R. E. Tulloss (ret)
2012-06-11 20:09:57 CDT (-0400)

It is most probable that there is no bulb inside the sac-like volval on the stem’s base. The presence of a bulb in a sac (membranous or breakable) has been recorded a few times (but only from South America and Australia).

My guess is that you will find this species belongs in sect. Vaginatae. The absence of floccose material on the stem and the absence of volval. material on the cap both lower the probability that this is assignable to sect. Amidella.


Created: 2012-06-11 17:35:57 CDT (-0400)
Last modified: 2012-06-12 19:00:12 CDT (-0400)
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