Observation 139315: Xerocomus Quél.
When: 2013-07-09
No herbarium specimen

Proposed Names

58% (1)
Recognized by sight
60% (2)
Recognized by sight: Xerocomus s. str. if the spores have a bacillate ornamentation :)
27% (1)
Recognized by sight

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Christian (Christian Schwarz)
2013-07-11 12:44:42 PDT (-0700)

Yeah I agree with you, Walt regarding chemical tests. I basically meant to say that our current understanding of them is unreliable.

I don’t know what’s happening with the taxa you mentioned. Presumably a lot of new genera will be erected. But my conversations with Todd Osmundson and others suggest to me that it’s going to be a long, messy road. Apparently it’s thought that boletes are such an old lineage that change and then reversal of that change has been a common pattern in their DNA signatures, making ancestry tracing difficult.

And yes I think it has been made fairly clear at this point that Boletus sensu stricto will be the Ceps and maybe some allied taxa.

I.G. I mean the strict-sense Xerocomus (X. subtomentosus and it’s allies). How much more will be included in that when things are “settled” I don’t know (it may include some or all Phylloporus).

Large can of worms
By: I. G. Safonov (IGSafonov)
2013-07-11 12:30:38 PDT (-0700)

Taxonomically, both Boletus and Xerocomus are still a giant mess, and the deeper we dig (molecular genetics vs. phenotypic characteristics), the more confusing it gets for us, amateur mycologists. Go ahead and read Josef Šutara’s treatment of Xerocomus s. l. and Xerocomus s. str. Also, according to the recent studies by Nuhn, Binder et al. (their 2013 paper in Fungal Biology), Xerocomus is a “heterogenous genus of polyphyletic origin”. When you say “classic Xerocomus”, do you suggest the description in http://boletales.com/genera/xerocomus (bottom paragraph) and do you imply Xerocomus s. str. rather than Xerocomus s. l.?

Christian, Chemical tests can be unreliable
By: walt sturgeon (Mycowalt)
2013-07-11 12:14:19 PDT (-0700)

in my experience, often depending on the age of the specimens. So ceps are going to be the only Boletus? What is happening with Boletus frostii, Boletus sensibilis, Boletus chrysenteron etc.? As for Xerocomus, I am old school (and old) and don’t like the genus. DNA be damned. Also is Austroboletus still an accepted genus? I could research these questions but it is easier to ask someone who already knows!

I think the genus Xerocomus
By: Christian (Christian Schwarz)
2013-07-11 10:30:07 PDT (-0700)

is pretty well supported as distinct from Boletus, which only contains the porcini group, as far as I’m told. This looks like a classic Xerocomus to me.

As for ammonia tests, I have yet to see a single study anywhere that correlates sequence data or mating compatibility results with chemical reactions.

Ammonia test
By: I. G. Safonov (IGSafonov)
2013-07-11 10:28:26 PDT (-0700)

This would then rule out B. subtomentosus_. On the other hand, the gross morphology still points in that direction…

Ammonia was dark green to black on the cuticle.
By: walt sturgeon (Mycowalt)
2013-07-10 14:21:14 PDT (-0700)
B. subtomentosus
By: I. G. Safonov (IGSafonov)
2013-07-10 10:25:27 PDT (-0700)

Yeah, this looks like something from the subtomentosus group. Note the xerocomoid pore surface and wide-mesh reticulation-like ribs at the upper portion of the stipe. The ammonia test would be nice to have here…

Could be
By: walt sturgeon (Mycowalt)
2013-07-09 19:03:45 PDT (-0700)

Although I think that genus will not stand the test of time. This is what passes for Boletus subtomentosus here. It is not.

Looks like a Xerocomus?
By: Christian (Christian Schwarz)
2013-07-09 18:43:59 PDT (-0700)

Created: 2013-07-09 18:14:42 PDT (-0700)
Last modified: 2013-07-11 12:47:47 PDT (-0700)
Viewed: 67 times, last viewed: 2016-10-28 03:07:41 PDT (-0700)
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