Observation 10139: Amanita flavoconia G.F. Atk.

When: 2008-08-10

Collection location: Jonesville, New York, USA [Click for map]

Who: Douglas Smith (douglas)

Specimen available

Under mostly oak, but at the edge of a mixed forest.

9/4/2008 – Looking at the spores on Aug 30 -

As suggested looking at the spores to help check the id here. The first micro-shot is of veil tissue from the right most ‘shroom in the second photo, at 1000x in Meltzer’s. Here the spores are ellipsoid and amyloid.

The second micro-shot is of spores from the veil tissue of the middle ‘shroom in the second shot, at 1000x in Meltzer’s. Here the spores are ellipsoid and amyloid.

Looking at the right most ’shroom I find the ave spore : length – 8.20 +/- 0.36 (err 0.12) um, width – 5.82 +/- 0.21 (err: 0.08) – q : 1.41 +/- 0.08, on 12 spores.

Looking at the middle most ’shroom I find the ave spore : length – 8.27 +/- 0.35 (err 0.11) um, width – 5.67 +/- 0.20 (err: 0.08) – q : 1.46 +/- 0.04, on 13 spores.

And these numbers are consistant wiht each other, so these are the same species as far as I can tell, and the spores are ellipsoid and amyloid, which from the comments suggests these are A. flavoconia.

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Oh, yes
By: Douglas Smith (douglas)
2008-09-23 07:56:55 PDT (-0700)

All microscopic work from dried material. This was all a couple weeks after getting the stuff. The spores were taken from veil material, dried, not from the gills.

frostiana eliminated…
By: R. E. Tulloss (ret)
2008-09-22 21:46:58 PDT (-0700)

The spore measurements (even just the Melzer’s reaction) eliminates A. frostiana. Were the spores measurements from dried material?


There is a possibility there are as many as 3 species here…
By: R. E. Tulloss (ret)
2008-08-29 06:12:22 PDT (-0700)


I would suggest a little exercise in spore measurement based on the pictures with this observation. The uppermost picture shows two specimens with yellow caps and white stems. These are the characteristics of the Peck species A. elongata. Check out the spore measurments for this species on the species’ page at Amanita Studies. Also, more spore data detail (and one page comparison with other taxa suggested below) is available here."

In the second picture, my question is whether the center specimen of three is a possible A. frostiana. Notice the differences in distribution of volval material on the lower stipe among the three specimens depicted. It is NOT quite what I would expect for frostiana, but it does suggest a “muscarioid” distribution of volva. If the middle specimen is frostiana, it will have subglobose inamyloid spores instead of ellipsoid, amyloid ones as in flavoconia. I agree that the two flanking specimens are likely to be the latter. Amanita frostiana is uncommon enough so that exploration of the possibility is worthwhile.

I hope that you have the opportunity to make these checks and inform us all about what he finds.

Very best,


Created: 2008-08-28 20:38:15 PDT (-0700)
Last modified: 2008-09-04 10:02:29 PDT (-0700)
Viewed: 367 times, last viewed: 2018-11-07 16:25:13 PST (-0800)