Observation 45715: Amanita sect. Vaginatae sensu Zhu L. Yang
When: 2010-05-14
Who: zaca
Herbarium specimen reported

Notes: Found under Quercus sp. trees.
Spores measures:
9.2 [10.8 ; 11.1] 12.7 × 8.7 [10.3 ; 10.6] 12.2
Q = 1 [1 ; 1.06] 1.1 ; N = 106 ; C = 95%
Me = 10.93 × 10.43 ; Qe = 1.05

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Reagents and bibliography
By: zaca
2010-05-23 17:05:55 FNT (-0200)

Many thanks to Dr Tulloss for all the valuable information he added. As a matter of fact, I’m not used to these kind of reagents and thus I will look forward to obtain them.

Thank you for the added information…
By: R. E. Tulloss (ret)
2010-05-23 15:19:15 FNT (-0200)

The reaction to phenol seems very weak. Phenol is not very selective as to the phenoloxidase (enzyme) that triggers any change of color. Unless your phenol was very, very diluted, it looks like the concentration of phenoloxidases is low in the stipe of your material. If you use syringaldazine (specifically detects laccase) or paracresol (specifically detects tyrosinase) you will get a reaction that you can interpret in terms of which enzyme is present. I have had the opportunity to test A. crocea with both these reagents when I was collecting in Scotland in 1988. In both cases, the positive reactions were located in the INTERIOR of the stipe base. I believe some of the information about these tests is in the following article:

Tulloss, R. E. 1998. Notes on Amanita crocea and phenetically related taxa and preliminary findings concerning some material determined as Amanita crocea in Mexico and the U.S.A. Boll. Gruppo Micol. G. Bresadola 40(2-3): 447-455.

I also suggest that you check out the method for carrying out spot tests for phenoloxidases that was published by C. D. Marr. It ought to be referenced in the “methodology” PDF that is available on the Amanita Studies web site.

Very best,


crocea… + The last photograph (pair)
By: zaca
2010-05-22 14:01:31 FNT (-0200)

Let me give the details about the spores measurements for the specimen under consideration. All the values below were calculate as mentioned in the site
Amanita Studies under the title “Meaning of Biometric Variables”: [106/1/1]
L: (8.32) 9.66 – 12.57 (13.43), L’= 10.93;
W: (7.97) 9.2 – 12.01 (12.73), W’=10.43;
Q: (1.00) 1.01 – 1.11 (1.17), Q’=1.05.

Hopefully Dr. Tulloss found a meaning for the last picture (pair of photos), that I didn’t thought about. However, the purpose of this of this pair of photos was to illustrate the reaction to a drop of Fenol (solution of 3%). These two photos were taken with a break of 2 minutes.

Let me add that, in the same day, I collected another specimen, about 150 meters away. It was very similar morphologically to this one and produced the same reaction to Fenol. I didn’t make spore measurements for this one.
Many thanks to Dr. Tulloss for his comments and observations,

The last photograph (pair)
By: R. E. Tulloss (ret)
2010-05-21 01:08:58 FNT (-0200)

It looks like this species leaves the internal limb of the volval sac on the stipe base as the latter lengthens upward. The lower part of the stipe lengthens sufficiently to bring the internal limb out of the top of the sac as a sort of anklet on the stipe. This seems rather distinctive; however, I do not recall a species that is described as developing in this way.


By: R. E. Tulloss (ret)
2010-05-21 01:02:09 FNT (-0200)

Cap color of crocea is much more orange…and not brown as in these photos.

The decoration on the stipe in A. crocea is pronounced and as depicted on the Amanita Studies website. [Thank you for citing the website in your observation!]

The spores of crocea are less round than the measurements provided for this observation.

Here is my data from 18 European collections (N=521):

[521/27/18] (8.0-) 9.4 – 11.8 (-18.8) × (7.5-) 8.5 – 11.0 (-16.0) µm, (L = (9.8-) 10.0 – 11.1 (-11.3) µm; L’ = 10.6 µm; W = (8.9-) 9.1 – 10.5 µm; W’ = 9.7 µm; Q = (1.01-) 1.04 – 1.16 (-1.28); Q = 1.07 – 1.10 (-1.11); Q’ = 1.10)

Following the observer’s notation, my data would yield: Me = 10.6 × 9.7; Qe = 1.10. I would encourage the observer to include ranges of average length, width, and Q per specimen as well as an overall average.

Interesting looking species.

Very best,


Created: 2010-05-20 21:20:16 FNT (-0200)
Last modified: 2012-06-06 19:39:21 FNT (-0200)
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