Observation 193165: Amanita sect. Phalloideae (Fr.) Singer

When: 2014-09-19

Collection location: Cedar Creek Ecosystem Science Reserve, Bethel, Minnesota, USA [Click for map]

Who: bckarch

Specimen available

Mushroom has a white smooth cape. The white gills are free from the stipe. Gave a white spore print. The stipe was white also and had a egg like volva at the base and an anulus near the point where the cap & stipe meet.


BK025 Pic.jpg
2 spore basidium.
2 spore basidium.
2 spore basidium.
2 spore basidium.

Proposed Names

-1% (2)
Recognized by sight
Used references: Mushrooms of the Midwest
57% (1)
Recognized by sight: Check KOH reaction on cap and microscopic features

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Do you have the .ab1 files from the sequencing effort?
By: R. E. Tulloss (ret)
2014-12-14 07:13:02 WIB (+0700)

If so, I’d like to look at them. Maybe there is some useful fragment.

Very best,


No problems happy to help and learn.
By: bckarch
2014-12-14 05:35:22 WIB (+0700)

I am still in undergraduate but am taking a basic mycology course at IU Northwest with Dr. Avis. For the class we have been learning about fungi from basidiomycota to chrytidiomycota. For our lab we have been foraying to build a collection & identify using keys, mushroom observer, and even DNA. Sadly my Amanita didn’t have a good sequencing to do a BLAST search but some people in my class did. We are ending classes soon so I’ll be able to send you sample soon.

Thanks for everything. A lot of useful information and interesting study of mycology that I feel many in my class will continue including myself no matter where we end up in our careers.


Thanks very much.
By: R. E. Tulloss (ret)
2014-12-13 20:55:11 WIB (+0700)

It has been interesting watching you work through some issues with your material.

I’ve been working on Amanita for more than 36 years. A small group of folks work with me to keep my herbarium in good order as new specimens come in from various sources (now, especially from mushroomobserver observers), sample material for DNA sequences, help edit sequences and prepare them for submission to GenBank, do some microscopy, etc. We have many, many irons in the fire.

One of the irons in the fire is to help sort out the eastern North American species of destroying angels. We have a very modest in-house database of DNA sequences that are useful in making a first-level sorting of taxa that, notoriously, look very much alike. Some of the species have a gestalt that is hard to put into words. For years Walt Sturgeon maintained to me that his material that became the foundation for the temporary code Amanitasp-O01” was distinct from more slender species of the destroying angels. Genetic studies show he was quite correct. With some recent poisoning cases, we have now about a half-dozen distinct species that frequently (if not always) turn yellow with KOH and, apparently, contain mycotoxins.

Hopefully, we will work our way further through this subject as more collections and more data become available. Your material will, I am sure, be helpful.

What course are you taking?

Very best,


Sure I’ll send a piece!
By: bckarch
2014-12-13 13:44:07 WIB (+0700)

Thank you so much for the help. I’ll send a piece to you! I see the address on your profile and will send a pie slice. I’m currently using my preserved piece for a mycology class but will send a slice as soon as I can. I see you are doing a lot of interesting research with Amanita and its definitely interesting to see how microscopic features can be very important in distinguishing Amanita species.


What would really be nice is to be there looking through your scope.
By: R. E. Tulloss (ret)
2014-12-12 12:46:55 WIB (+0700)

Your micro pictures are nice.

The basidia don’t look like typical bisporigera basidia to me. I’m sure that you moved the focus up and down to be sure that there were or were not some out of focus sterigmata that don’t show in the photographs. In order to have sharp focus at highest magnifications, the the depth of the sharp focus is very shallow. A sterigma on the near side of a basidium can be in focus and a sterigma on the backside of a basidium can be invisible, so the constant or frequent adjustment of focus is necessary to get a complete picture of what is present in three dimensions.

There are cases of temporarily having some two-sterigmate basidia. I noticed that many of the basidia in your nice images have no sterigmata present at all. So there is a possibility that your photographs depict a more or less immature part of a hymenial surface. Some species of Amanita (as if they are really desperate to get some spores out into the world quickly) will produce 2-spored basidia early in sporulation. Such spores may be bigger than those normally produced by the same mushroom once sporulation is further underway. This sort of temporary use of two-spored basidia may be species dependent, moderately common, and distributed over several sections of the genus. I first noticed it in sect. Vaginatae.

Very best,


The sterigmata of A. bisporigera are very unique.
By: R. E. Tulloss (ret)
2014-12-12 12:27:51 WIB (+0700)

If you make a thin section across a gill, you can see the basidia from the side. The basidia of bisporigera have exaggerated pairs of sterigmata (longer and thicker than in most basidia of other species of section Phalloideae). These sterigmata tend to point slightly away from eacy other making me think of the old rabbit ears on television sets in non-cable households. This character of the sterigmata is common enough and independent of the degree of development of the spores so that it only take a few moments to find the sterigmata in a reasonably good section. It is not even necessary to use a stain. Of course, the higher the magnification the better.

All the species that I mentioned below will turn yellow with KOH most of the time (for some reason it doesn’t always work. I have had KOH fail to produce yellow in cases in which the concentration of the KOH was known to be sufficiently high to produce a good strong yellow and genetics (later) showed that the species was one of the “yellow-stainers.” I don’t think anyone understands the chemistry well enough at this point. If someone know of new results in this area, I’d love to hear about them.

If you’d be willing to send me a pie slice from the cap of your dried specimen, I’d be glad to take a look at it and see if we can get an ID for you.

Very best,


KOH Yellow & 2 Spore Basida
By: bckarch
2014-12-12 10:52:21 WIB (+0700)

I did a KOH test on the Amanita today and it was yellow. I also looked under the microscope to see how many spores for the basidia. I saw two spored basidia but wanted to ask the question how do you determine if it is 2 spored? I figured to count the sterigmata on at the top as the way to determine the # of spores. I am adding some pictures of a basidium with only 2 sterigmata on top and also of a developing basidium where the spores are just forming and migrating to the sterigmata. There are only 2 spores developing and only 2 developing sterigmata. Not sure if this is how to determine if the basidium is only 2 spored.

There’s also a chance that this is A. suballiacea (we don’t know its northern range limit).
By: R. E. Tulloss (ret)
2014-12-12 01:08:53 WIB (+0700)

We know it occurs in Michigan:


Very best,

Rod Tulloss

It’s really necessary to see the 2-spored basidia to determine bisporigera.
By: R. E. Tulloss (ret)
2014-12-12 01:06:59 WIB (+0700)

However, it’s also often rather small. What you have here is more likely to be A.sp-O01” or A.sp-bisporigera04.”



Very best,

Rod Tulloss

Created: 2014-12-11 23:29:00 WIB (+0700)
Last modified: 2014-12-12 10:54:31 WIB (+0700)
Viewed: 116 times, last viewed: 2018-02-20 10:12:33 WIB (+0700)
Show Log