Observation 49658: Amanita aestivalis Singer ex Singer

When: 2010-08-03

Collection location: Mansfield Center, Connecticut, USA [Click for map]

Who: Kira (Kiradee)

No specimen available


[admin – Sat Aug 14 02:02:38 +0000 2010]: Changed location name from ‘Mansfield Center, CT’ to ‘Mansfield Center, Connecticut, USA

Proposed Names

30% (2)
Recognized by sight
54% (1)
Recognized by sight: See RET’s comment(s).

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Chemicals on amanitas…
By: R. E. Tulloss (ret)
2010-08-05 08:52:08 PDT (-0700)

The new Amanitaceae website has a data field for macrochemical spot testing information for each species that has been tested. If I remember correctly, the number of species tested by me personally is over 130.

Sulfuric acid (conc.) – (different on different tissues and, apparently with reactions somewhat useful, but largely unstudied): color flash or a bit less transient, pink, purplish, lavender…that sort of range.

strong base (e.g., KOH 5% aqueous) – famous yellow to yellow orange reactions on various body parts in section Phalloideae…usually on the entirely white taxa.

syringaldazine in ethanol – lavender or purple when sufficient laccase is present, specific to the action of laccase (a phenoloxidase). The reaction is extremely strong in some lepidellas, but more often negative (e.g., see A. subsolitaria and the ESPECIALLY, dramatic reaction in a complete cross-section of a fruiting body of A. abrupta).

There’s another phenolic compound….doggone. it’s water soluble and non-carcinogenic and (like the syringaldazine soluntion) can be carried into the field… Oh, yeah. Paracresol (aqueous) – shades of orange and red when sufficient tyrosinase (phenoloxidase that triggers many of the pigment creating cycles in plants, fungi, etc.) is present. L-tyrosine is also specific to tyrosinase but has the disadvantage of having to be dissolved in water at the boiling point just before application (not easy to do in the field!).

Cresol is often mentioned in old books, but it is not selective (interacts with lots of phenoloxidases). I can’t remember if there were health problems with its use, too. At any rate, paracresol and syringaldazine are both very satisfactory if you can locate enough to work with.

There’s a starter list. Of course, KOH, NH4OH, various stains, and Melzer’s Reagent are used for the chemistry in microscopic studies.

I think that there are forms to support data recording with syringaldazine and paracresol (L-tyrosine) on the old Amanita Studies site. Can’t remember. I’m pretty sure they’re on the new Amanitaceae web site (but that doesn’t do you much good at present). If you can’t find said forms on-line, I’ll email a PDF upon request. They fit on an 11 × 8.5 inch sheet of US letter-size paper.

Very best,


White, then
By: R. E. Tulloss (ret)
2010-08-05 08:36:05 PDT (-0700)

Then I’d say it was white, the center (if it weren’t white and was still a fit to the definition of A. aestivalis) would be pale yellowish or pale yellow-tannish.

I’ll vote for aestivalis.


By: Kira (Kiradee)
2010-08-05 07:06:57 PDT (-0700)


Well, it definitely was a white cap – besides the bruising and such, there definitely wasn’t any obvious brown. Whether or not it was VERY white is hard to say…

Good luck with the phylogenetic work! I’d be interested to hear how that goes, if it goes.



Hi Rod,
By: damon brunette (damonbrunette)
2010-08-05 06:58:59 PDT (-0700)

You mentioned macrochemical testing for this species. Could you list what that would be? Is there a good resource for chemicals on Amanitas? i didnt think that chemicals worked very well on most of them…. Thanks, Damon.

Color perception…
By: R. E. Tulloss (ret)
2010-08-05 06:54:06 PDT (-0700)


If this species had a very white cap (except perhaps in the very center) with the exclusion of the stains and detritus, I think there is a possibility that you have what has been called A. aestivalis. Unfortunately, this species (if it is truly distinct from A. brunnescens) is differentiated by cap color, macrochemical spot testing, and relatively slower (much slower) staining than is seen in A. brunnescens. If there is a difference in the spore size/shape, it is very, very minimal. I have tried several times to support student phylogenetic work that might have produced information on the DNA of the two possibly distinct species.

So…I’ll post the alternative possible name. Only you saw the species and can say what the original color appeared to be in natural lighting.

Very best,


Created: 2010-08-05 05:44:35 PDT (-0700)
Last modified: 2010-08-26 18:40:20 PDT (-0700)
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