Observation 49656: Amanita flavoconia G.F. Atk.

When: 2010-08-05

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

27% (1)
Recognized by sight
82% (1)
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
The amyloid reaction is commonly demonstrated with a potato
By: R. E. Tulloss (ret)
2010-08-05 10:58:42 CDT (-0500)

or other starchy object in Middle School science classes. A drop of tincture of iodine is put on a slice of raw potato. Presto! Dramatic color change.

One of the reasons for carrying out the test I mentioned below on GLASS is that paper and wood are both likely to become permanently stained by iodine…which has a good chance of hiding the reaction (or lack of one) that you want to see in the spores.

Very best,


Thanks rod…. i will
By: damon brunette (damonbrunette)
2010-08-05 10:48:34 CDT (-0500)

try this experiment between the two the next time i get a flush of either one. Will read up on the amloid spore wall reaction… didnt know about this. Thanks!

striations are not enough to be SURE
By: R. E. Tulloss (ret)
2010-08-05 09:51:10 CDT (-0500)

A thin or old cap of A. flavoconia can have striations. I don’t know how many times I’ve checked a possible “frostiana” at a foray only to find that the striations are a result of environmental factors and/or a depauperate fruiting body; and the specimen is flavoconia, again.

The very best way to segregate the two species without a microscope is to collect a spore print on a piece of glass or glazed pottery (they don’t react with iodine) and put a drop of Melzer’s Reagent or tincture of iodine (this ought to work) on the spores.

Let’s assume that your only two choices for determination are frostiana and flavoconia_. If the spores get very dark blue-black, then you have the amyloid-spored species (_flavoconia). If the spores are the same color as the iodine solution, then the spores have not changed color (are inamyloid); and, then, the species is frostiana.

With a microscope, you can also see that the basidia of frostiana have clamp connections at the base, like all the muscarioid taxa (not true of flavoconia). In addition, the spores of flavoconia are ellipsoid (not subglobose as in frostiana).

At this point the teacher always says, “Now don’t feel bad about it if you have a problem. Remember Peck had specimens of flavoconia mixed in with his type collection of frostiana.”

The discovery of the amyloid spore wall reaction made a tremendous impact on Amanita taxonomy. That chemical reaction ALONE serves to segregate the two subgenera (Amanita and Lepidella) quite neatly (supported by DNA-based research).

Very best,


Using a hand lens….
By: damon brunette (damonbrunette)
2010-08-05 09:04:26 CDT (-0500)

With what i thought to be flavaconia… i saw striations. Should i be able to see it with a naked eye, or ANY striations would push it frostianna?

You were the observer…
By: R. E. Tulloss (ret)
2010-08-05 08:59:33 CDT (-0500)

Your view is important. I will increase the weight of my vote for flavoconia.


By: Kira (Kiradee)
2010-08-05 08:51:06 CDT (-0500)

I’m pretty sure that it wasn’t striated, or if it was, it was awfully subtle. I’ve put up a additional photo I took – the cap was very smooth.

I really can’t make up my mind whether the margin of the cap has striations …
By: R. E. Tulloss (ret)
2010-08-05 08:47:02 CDT (-0500)

underneath the wrinkles from in situ drying. Rats. The bulb appears to have a sort of short limb on one side. That seems ambiguous to me also. I’d say it is probably Amanita flavoconia, but there is still a chance that the condition of the cap is preventing us from seeing marginals striations, which might push us toward A. frostiana. In the collecting areas with which I am more familiar (to your east and south), ambiguous material is almost always A. flavoconia once you get it under the scope. So I’m going to give a vote leaning toward flavoconia.


Created: 2010-08-05 07:34:24 CDT (-0500)
Last modified: 2010-08-26 20:40:19 CDT (-0500)
Viewed: 66 times, last viewed: 2017-06-07 21:51:15 CDT (-0500)
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