Observation 52373: Amanita citrina sensu auct. amer.

When: 2010-09-08

Collection location: Forest near Elgin St., Pembroke, Ontario, Canada [Click for map]

45.797317° -77.132134°

Who: Paul Derbyshire (Twizzler)

No specimen available

Found in D2C, a pine-rich zone.

Proposed Names

9% (2)
Recognized by sight
54% (1)
Recognized by sight: Let’s see if the site can parse it.

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Paul Derbyshire (Twizzler)
2010-09-09 23:40:53 CDT (-0400)

The site thinks “sensu auct. amer.” is a species author, rather than, well, whatever it actually is. A qualifier of sorts I suppose, meaning “in the sense of” someone-or-other.

MO accepted a useful way of naming your images
By: R. E. Tulloss (ret)
2010-09-09 22:50:42 CDT (-0400)

Placing a heavy vote on bulbosa doesn’t change the probability (high in my opinion) that the image depicted is NOT bulbosa.

I’m going to back off on further comments on this observation and let people take it where they want to take.


By: Paul Derbyshire (Twizzler)
2010-09-09 21:39:44 CDT (-0400)

“It’s important to understand that a type specimen defines a species or a form or a variety and that that type doesn’t change when names change. When we collect a lavender-staining bulbosa-like (citrina-like) amanita, and we claim it is A. citrina f. lavendula, we are REALLY identifying it.”

And when we collect a non-lavender-staining bulbosa-like (citrina-like) Amanita? You’re proposing calling it Amanita citrina sensu auct. amer.? That’s a bit of a jawbreaker and I don’t know if the site will parse it sensibly…

Edit: I don’t know why the “sensu auct. amer.” part is appearing doubled when my comment is displayed. I didn’t duplicate it when I wrote it and it doesn’t show up duplicated when I edit it either. I take this as evidence that the site indeed won’t parse it sensibly, that I can’t even use it in a comment without Weird Things Happening™.

Not quite
By: R. E. Tulloss (ret)
2010-09-09 20:15:39 CDT (-0400)

I’m not arguing that A. citrina is an American species.

And I’m certainly not arguing that it’s wrong to deprecate Amanita citrina in favor of Amanita bulbosa.

It’s important to understand that a type specimen defines a species or a form or a variety and that that type doesn’t change when names change. When we collect a lavender-staining bulbosa-like (citrina-like) amanita, and we claim it is A. citrina f. lavendula, we are REALLY identifying it. We are saying that as far as we know, it belongs in the same group of organisms as does the holotype of f. lavendula. (By the way there isn’t one, but all Coker’s material exists; and I will select and publish the collection that I select as the LECTOTYPE, which is what one does when there is no holotype).

If a particular computer system cannot handle the fact that a name can be in use while at the same time the specific epithet in the name is not deemed correct, then the computer system needs to adapt to the situation in which real mycologists find themselves. However, I don’t think that MO has a problem in this particular regard. It is not trying to dictate correct usage of a species epithet for a taxon with an infraspecific rank (in this case, the rank of form). This is appropriately flexible; and, in the present situation, flexibility seems to me to b good.

My point is simply pragmatic. There are lots of names that are not correct AND are in use AND for which there is no extant replacement. Sometimes we just have to use the name that has been used for many years while we try to straighten out the problem.

Amanita citrina_ f. lavendula is one of those names. The species name is not accepted as correct, but the complete name is based on a group of collections deposited at NCU (Chapel Hill); and, from among these collections, a type can be selected. The taxon is awaiting a good name. I am intentionally not speculating on what that name might be because that could lead to problems with the use of my “speculative” name for the entity. To keep the practical problems to a minimum, we need to keep using a name that has a real flaw.

I am starting to be sorry, that I suggested americitrina, it was intended to be a new name for another taxon that I thought was not the same as f. lavendula. You see, this is why I realize that putting provisional names into general use can be a bad idea.

When I have a specimen that I can satisfy myself is A. citrina f. _lavendula, I am going to continue calling it by the existing name…until I am certain that a change is the right thing to do (I am) AND that I am proposing the right change (at this moment, I don’t know what that is).

I’m not going to use the name americitrina. I am going to say instead citrina sensu auct. amer. like we do with franchetii sensu Thiers_, and that will be that until we have a better understanding.

This is the solution that I recommend.

Very best,


Right now
By: Paul Derbyshire (Twizzler)
2010-09-09 17:58:09 CDT (-0400)

I’m just concerned with the pragmatic matter of what to call this particular fungus in this particular observation. The site says A. citrina is deprecated in favor of A. bulbosa; looks like you’re basically arguing that’s wrong, and A. citrina and its f. lavendula are North American taxa and A. bulbosa is a similar, European taxon that lacks a lavender-turning form or variety?

On the other hand, I noted that someone created an A. americitrina name at some point. What’s the story on that, or is there no connection?

Regardless, this observation has to be called something. I’ll go with the site’s deprecation for the time being and let someone else worry about whether it should be changed, and rename some of my observations (if necessary) then.

a response
By: R. E. Tulloss (ret)
2010-09-09 17:23:10 CDT (-0400)

I wish there were simple answers for questions like this, but there are very few taxonomists and a very large number of problems. You have struck on a few.

Several years back, it was noticed that a Norwegian mycologist had created an Agaricus citrinus before Schaeffer did. Thus the end of the latter as a valid name.

Schaeffer had created Agaricus bulbosus for the white variety of the same species. This is widely accepted in Europe. In fact several European mycologists have mentioned that they think that the white and citrine “varieties” may be color forms not deserving of separate names at an infraspecific rank (i.e., below the rank of species). At the moment the two European entities are correctly named A. bulbosa.

This doesn’t have any impact on our North American critter except that the name needs to be changed as Paul notes.

BUT PLEASE NOT BY PLACING IT IN BULBOSA. That is not the only option. There is at least one better option, and it takes a LOT OF WORK.

There is plenty of evidence that what we have called “citrina” in N. America comprises at least one species DIFFERENT FROM THE EUROPEAN bulbosa. In fact we have one or two or three (at least) such taxa.

Are they all one species? Are they separate species?

These issues have not been sorted out. The types are probably TOO OLD to have DNA extracted, and nobody has looked at that part of the issue. I have done morphological work on the problem, but I haven’t had time to do enough work so that I could propose a hypothesis that I personally could believe is well-supported.

It appears that material satisfying the original description of “A. citrina var. lavendula” ranges from at least Cape Cod to the coast of the Gulf of Mexico. Some are very pale (almost white), some are the color of the specimen in Paul’s photos. Some have an annulus that becomes gray with age. But do all of them have this property? Do all of them turn lavender? Is cold the determining factor for a living specimen of a lavendula to turn something between lavender and amethyst? (Several MO regulars saw the latter on Cape Cod in the near freezing rain with overnight temperatures around 1 degree above freezing).

It will take considerable focused work beginning with superior collecting, superior taking of field notes, and experiments with refrigeration (to say the least) to get to where we need to be on the above questions. This probably is NOT something that will JUST HAPPEN. My experience indicates that even the web has yet to produce the person-power and person-hours necessary to make a coordinated attack on one little mycological taxonomic issue. The web connects us, but we are spread very thin, while the expertise is concentrated in a bunch of what I have recently learned are called members of the [old] Federation of Active Retired Taxonomists. Check out the unacceptable acronym. The general situation is called the “taxonomic impediment”—-namely, at the time we need the old specialists, we are training no new ones. Hello. The old folks are OLD. There are very few YOUNG folks. What the Hell are ecologists and molecular specialists and amateur scientists and amateur societies going to do when the OLD folks become the GONE folks?

So, Paul, you have uncovered not only a nomenclatural problem or a taxonomic problem. You have uncovered a social problem, a social priority problem, and (in multiple sense of the word) a POLITICAL problem.

Very best,


There seems to be some taxonomic confusion here.
By: Paul Derbyshire (Twizzler)
2010-09-09 15:58:08 CDT (-0400)

This looks like Amanita citrina, without any evidence for it being specifically the lavendula form; the site says A. citrina is deprecated in favor of A. bulbosa, apparently a name change that’s occurred since our A. citrina season wound down last year.

Further odd is that it now looks like A. citrina f. lavendula is not deprecated even though its enclosing taxon is.

Someone with the appropriate references, connections, or expertise on nomenclatural matters needs to sort this out, I fear.

Probably not in North America
By: R. E. Tulloss (ret)
2010-09-09 11:16:52 CDT (-0400)


Created: 2010-09-09 01:18:47 CDT (-0400)
Last modified: 2010-09-09 22:36:45 CDT (-0400)
Viewed: 124 times, last viewed: 2017-06-08 00:04:35 CDT (-0400)
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