Observation 187975: Amanita rubescens Pers.
When: 2014-09-07

Notes: The fungus was found growing underneath the shade of trees in an area with lots of grass and very dense, dark soil.

It did not have a distinct smell.

The fungus’s pileus had a diameter of 10.3 cm, and it was cream with some white and some reddish brown scales. It had an areolate surface, and it had a relatively smooth margin. The pileus had a depressed shape to it, and the inside of it was white.

The gills of this fungus were adnate, had an even margin, and were white in color. They were approximately .5 mm wide, and they were spaced about 1 mm apart. From the stipe, the gills had a length of about 4.3 cm.

The fungus had a single-edged annulus that was white on both the top and the bottom.

This fungus’s stipe was central to the pileus and was also smooth. It was 9.4 cm long and 2.6 cm wide. The end of the stipe was bulbous, and the inside was solid. Both the inside and outside of it was white and partially dark rose. It had an institutious base.

This fungus had a napiform shaped bulb, and remnants of a volva were located on top of its pileus.

Its spore print produced a creamy white color. The spores had a round shape to them, and their sizes ranged from 5.6 to 6.2 microns in diameter.

Proposed Names

54% (1)
Recognized by sight
Used references: Mushrooms of the Midwest by Michael Kuo and Andrew S. Methven
81% (1)
Eye3 Eyes3
Recognized by sight

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Add Comment
Hello, Mr. Tulloss
By: Halley Staples (halstapl)
2014-11-11 17:38:05 CST (-0500)

Yes, the partial veil is white on both the top and the bottom of this fungus.

Thank you for clarifying that it is not the volva itself that is napiform, but instead it is the bulb that has this shape. I changed this description in my observations.

I also appreciate all of the resources that you have given me to help further understand the terminology of the species in Amanita.

Hello, Halley.
By: R. E. Tulloss (ret)
2014-11-10 15:41:21 CST (-0500)

This mushroom is one of species that used to all be called Amanita rubescens in North America. We’ve found that that name applies only to some similar European amanitas.

I can see that the top of the partial veil is white. Is that true of the bottom also?

If the bottom of the partial veil is white and not yellow, then it is possible that you have a specimen of Amanita rubescens var. alba Coker. According to research to date, this is probably a good species on its own, which will get a name when we have as good a case as we can make based on well-organized data.

Here is a link:


On the technical tab of the above web page, you will see some spore comparisons to similar white taxa that are rubescent (turn reddish). Associated with these spore data comparisons are links to the other taxa. There are apparently many rubescent taxa in the U.S. distinguishable with genetic data. I’m trying to keep track of the information in a way accessible to the public.

your notes on this observation are good. I would make one suggestion: A bulb is different from a volva. A volva can cover a bulb or leave remains on top of the bulb, or leave remains in the soil around a bulb. What is napiform is the bulb in this case. What is the volva is crumbling on the cap and around the bulb and stipe base. Lots of books call the bulb a volva. To get a more in depth understanding of the development of the Amanita fruiting body and the naming of its parts, I suggest the opening section of a paper by the late Dr. C. Bas. You can down load this part of the paper from the www.amanitaceae.org web site.

The link is in the text of the first bullet item on the following page;


The link will connect you to a PDF download based on the introduction to Dr. Bas’ 1969 thesis.

Very best,


Created: 2014-11-10 14:28:37 CST (-0500)
Last modified: 2014-11-11 18:17:49 CST (-0500)
Viewed: 39 times, last viewed: 2016-10-26 14:54:12 CDT (-0400)
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