Observation 171125: Amanita rhacopus Y. Lamoureux

A week of very dry weather can significantly change the appearance of mushroom. Although I believe this one qualifies as a rhacopus type, the gray ring of UV material atop the stipe base is barely noticeable (5th photo). The gray UV patches on the cap have constricted into hard little pyramids.

Dehydrating and will include in Friday morning’s package.


Proposed Names

92% (2)
Recognized by sight

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

= Observer’s choice
= Current consensus


Add Comment
Rod, I see you have chosen for analysis…
By: Dave W (Dave W)
2015-11-27 11:00:02 PST (-0800)

material representing various stages of development; exhibiting differing macro traits. It adds up to a nice overview for field-recognition of A. rhacopus… not to mention the advancement of the scientific understanding of the species.

As always, thanks for taking the time to share your knowledge.

DNA sequence of the “proposed fungal barcode” gene from Linas Kudzma…
By: R. E. Tulloss (ret)
2015-11-27 07:51:48 PST (-0800)

demonstrates that this is A. rhacopus.


Thanks Dave,
By: groundhog
2014-09-16 09:26:14 PDT (-0700)

We have recieved this material and accessioned it to Rod’s Herbarium. We have scheduled it for DNA sequencing.

Yes, the provisional names and temporary codes appear to relate…
By: R. E. Tulloss (ret)
2014-07-26 20:40:22 PDT (-0700)

to genetically distinct taxa. Two of the taxa in the “rhacopus group” appear to be much more common than the others. The differences discussed with David on this page relate to these two “apparently most common” taxa: The taxa that I propose to be Yves Lamoureux’s “rhacopus” (a number of people have interest in this name and consensus is hoped for) and the taxa with the temporary code “sp-T01”.

There are as many as ten genetically separable taxa involved in the group that used to be called ceciliae or inaurata in eastern North American field guides. Some of these are given at least fragmentary treatment on the WAO site:

rhacopus,” “sp-56,” “sp-N59,” “sp-QUE03,” “sp-T01,” and “sp-V03.”

Four others are known only from single collections.


have these very similar grisettes …
By: Debbie Viess (amanitarita)
2014-07-25 09:44:44 PDT (-0700)

been DNA delimited yet? Subtle color differences and vaguely different spore size: "It was given a separate code number on the basis of the darker cap and what appeared to be larger spores … " doesn’t seem to be very strong evidence for a new species.

By: R. E. Tulloss (ret)
2014-07-25 04:55:29 PDT (-0700)

is widespread in the U.S. You could have it.

Very best,


I have found fresh material…
By: Dave W (Dave W)
2014-07-24 20:36:28 PDT (-0700)

that is very dark at this location.

Thanks, David.
By: R. E. Tulloss (ret)
2014-07-24 19:14:38 PDT (-0700)

The second image shows a very dark cap. But there was drying going on as you note. A fresh cap that has a dark gray tint to the brown often has been an indicator of A. sp-T01. But I’m not suggesting that here because of the aging/drying.

Very best,


Created: 2014-07-24 18:16:25 PDT (-0700)
Last modified: 2017-12-28 20:39:45 PST (-0800)
Viewed: 92 times, last viewed: 2018-09-20 11:59:52 PDT (-0700)
Show Log