Observation 185699: Amanita rubescens Pers.
When: 2014-10-26
Who: zaca
No herbarium specimen

Notes: Growing under oaks.

Images

474501
Sp.1&Sp.2
474502
Sp.1
474503
Sp.1
474504
Sp.1
474505
Sp.1
474506
Sp.2
474507
Sp.2
474508
Sp.2
474509
Sp.2
476425
Microscopy: Spores and Globose cells from the gill edge;
476430
Microscopy: Basidia.

Proposed Names

-6% (2)
Recognized by sight
29% (1)
Recognized by sight
86% (1)
Eye3 Eyes3
Recognized by sight

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

Eye3 = Observer’s choice
Eyes3 = Current consensus

Comments

Add Comment
You are welcome, zaca.
By: R. E. Tulloss (ret)
2014-10-30 21:55:57 CDT (-0500)

I noticed some spelling errors and missing words in my previous comment. I fixed those that I found.

R

Yes, you were right from the beginning, …
By: zaca
2014-10-30 19:23:10 CDT (-0500)

Many thanks for teaching me your thoughts about these topics. Let me say that the reasoning is “perfect”. So, let me put the correct name on the specimens and thank you for the clarification, Dr. Tulloss.
Kind regards,
zaca

That looks pretty good to me.
By: R. E. Tulloss (ret)
2014-10-30 18:46:09 CDT (-0500)

I think if you combine the spore data and the photos, and then compare the photos with the ones from MO observations by pinknailgirl, you have pretty good evidence that you have something that is presently called A. rubescens.

Congo Red is a pretty good cell wall stain that will bring out clamps if they are there.

You cannot prove a negative by sampling or other methods of observation, i.e., any methods of science. This is why, in technical papers, I don’t say “clamps lacking.” In that context, the only thing you can say is “after extensive search I didn’t find any clamps.” I have been told by reviewers to say “clamps absent” and I refused because I like to think that I am doing science. If I wish to offer a hypothesis concerning clamps in section Validae, then that should be in a section entitled “note” or “discussion” and not intermixed with observations.

A summary report of observations might take a form like this: “In examining specimens of section Validae for the presence of clamps, I have never found any after searching diligently each time.” You can strenthen the point by adding, “Dr. Bas reported the same experience regarding his examination of collections assigned to the Validae.” Your next move is likely to be rhetorical…i.e., when you stop giving evidence, you may start trying to convince others that you have a plausible hypothesis with regard to clamps’ presence in the Validae, namely, “There are very few if any.”

Very best,

Rod

Unable to decide about …
By: zaca
2014-10-30 16:02:26 CDT (-0500)

clamps, but the spores fit very well A. rubescens:
(7.6) 8.1 – 9.9 (10.3) x (5.4) 5.6 – 6.6 (7.8) µm
Q = (1.3) 1.4 – 1.6 (1.7) ; N = 25
Me = 8.8 × 6 µm ; Qe = 1.5.
Concerning the clamps at the basidia, I can say that some don’t have, but for the others I doubt. My doubts are probably related with the fact that I was not able to find a reagent that give enough contrast to decide. OK, the preparations themselves are not sufficiently good.

You’re very welcome.
By: R. E. Tulloss (ret)
2014-10-27 08:23:57 CDT (-0500)

Rod

OK!. Thanks.
By: zaca
2014-10-27 03:54:17 CDT (-0500)
I added Bas’s description (macro and micro) to the techtab for
By: R. E. Tulloss (ret)
2014-10-27 00:05:03 CDT (-0500)
Unfortunately …
By: zaca
2014-10-26 20:06:28 CDT (-0500)

I don’t have Dr. Cornelis Bas thesis, but I understood your point, though it will not be easy for me to know if clamps are present or not at the bases of basidia. Nevertheless, I will try.
Thanks again,
zaca

Hello, Zaca…..EDITED
By: R. E. Tulloss (ret)
2014-10-26 19:45:42 CDT (-0500)

Bas indicates that sometimes the spores of solitaria can be longer and have higher Q than do the spores of rubescens that I have measured. Cristina’s revision of Czech material of solitaria produced spore measurements that were shorter and had lower Q than those reported by Bas. I think that that particular Czech material may have been immature or had some other external factor that effected spore size and shape.

One fundamental difference between solitaria and rubescens is that soliltaria (and all species of Bas’ stirps Solitaria) have clamps at the base of some basidia. Amanita rubescens and all known species of sect. Validae lack clamps at the bases of all basidia.

If you have access to Dr. Bas’ thesis, you can run your material through the key. I would note however, that the margin of the cap in your photographs does not appear to be appendiculate. Hence, the species may not belong in section Lepidella on that account.

Very best,

Rod

Yes, you are right …
By: zaca
2014-10-26 18:04:35 CDT (-0500)

I have seen those stains, but I went in another direction. So, it could be A. rubescens. I will try the microscopy in the forthcoming days. Can you give any recomndation about it?
Thanks, Dr. Tulloss, for the comment.
Kind regards,
zaca

There are stains on the cap and stipe that suggest this might be the rubescent…
By: R. E. Tulloss (ret)
2014-10-26 17:52:53 CDT (-0500)

taxon that Elsa has sent me from Portugal in recent years.

Very best,

Rod

Created: 2014-10-26 16:40:13 CDT (-0500)
Last modified: 2014-10-30 19:24:53 CDT (-0500)
Viewed: 65 times, last viewed: 2016-10-29 09:44:29 CDT (-0500)
Show Log