Observation 86841: Amanita Pers.
When: 2011-09-03
38.53° 78.15°
No herbarium specimen
0 Sequences

Fruiting on the ground.

Proposed Names

56% (1)
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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Very helpful. Thanks.
By: Penny Firth (pfirth)
2012-01-22 15:59:57 CST (-0500)
Penny, It may be OK, but iodine might build-up in the plastic and stain it.
By: R. E. Tulloss (ret)
2012-01-22 12:05:25 CST (-0500)

The point is not to use things like paper and wood which will darken due to the presence of starches or starch-containing compounds and fool you into thinking that the spores in the spore print are turning dark.

If you put iodine on a potatoe in the 7th grade (or thereabouts) you have seen the amyloid reaction. The amyloid reaction divides the genus Amanita just about in half (with very few known exceptional cases). An amanita is in one of these sections (Amanita, Caesareae, and Vaginatae) if the spores don’t darken with iodine (are inamyloid). Otherwise, the spores become blue-black (I can’t see the blue myself) and the section is either Amidella, Phalloideae, Lepidella, or Validae. The spores are said to be “amyloid” if they turn dark in iodine. The known possible exceptions to the alignment of iodine reaction with subgenus are in the Old World tropics and number less than half-a-dozen to date…out of about 770 probable amanita taxa that are listed on www.amanitaceae.org (WAO).

Very best,


Thank you! I’ll add
By: Penny Firth (pfirth)
2012-01-22 11:28:22 CST (-0500)

iodine to my kit. Is it OK to spore print on heavy clear plastic rather than glass?


With the apparently striate margin,…
By: R. E. Tulloss (ret)
2012-01-22 10:26:57 CST (-0500)

it would have to be an aging flavoconia…and the distinct two-color pileus is also unusual for that species.

A red disc with the remainder of the cap yellow and a striate margin suggests something in sect. Caesareae to me; however, A. frostiana might also be a possibility.

Here are some references:

1. Normally nonstriate margin in sect. Validae:


Normally striate margin in subgenus Amanita:

2. In sect. Caesareae:

3. In sect. Amanita:

I think that sp-F11 and frostiana might be the most likely of these, but these are just guesses…and neither of the species is known from western Virginia…of the two frostiana might be in the Blue Ridge Mtns. or (more distantly) the Appalachians. Up to now, I only know sp-F11 from much farther south.

A spore print on glass or glazed ceramic surface and a drop of iodine would quickly separate the nonreactive spores of subgenus Amanita from the quickly darkening spores of sect. Validae.

Very best,


A. flavoconia…
By: Richard Kneal (bloodworm)
2012-01-22 08:19:19 CST (-0500)

is a possibility i would assume.

Thank you R, my 2012
By: Penny Firth (pfirth)
2012-01-22 08:13:04 CST (-0500)

resolution: more effective images.
best wishes,

This could be an Amanita
By: R. E. Tulloss (ret)
2012-01-22 07:46:09 CST (-0500)

But we need to see more of it…(here we go) especially the bottom of the stem. :-)

Very best,


Created: 2012-01-21 22:22:01 CST (-0500)
Last modified: 2012-01-22 12:54:55 CST (-0500)
Viewed: 84 times, last viewed: 2017-06-10 09:15:37 CDT (-0400)
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