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When: 2012-06-12

Collection location: Thomasville, Georgia, USA [Click for map]

Who: Kristine (JanusGD)

No specimen available


Proposed Names

73% (6)
Recognized by sight: Coarse reticulation on entire stipe. Red cap. Red pores. Looks like an older one with the colors a bit faded.

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= Observer’s choice
= Current consensus


Add Comment
Quite a piece of work, that Wu paper.
By: Dave W (Dave W)
2017-03-02 17:34:53 NZDT (+1300)

I downloaded and stored it. Thanks!

By: I. G. Safonov (IGSafonov)
2017-03-02 12:37:52 NZDT (+1300)

Glad you were able to get hold of the paper eventually.
I think it’s the most up-to-date Boletaceae tree in terms of the scope of genera, but not necessarily in terms of sampling (this is the improved version of their 2014 tree). The latter aspect is understandable because the phylogram looks quite complicated, almost unmanageable, as is. Seems like the authors used the latest and greatest version of statistical algorithms that allowed them to merge, not split. The fate of Exsudoporus is not surprising, but expanding Sutorius to accommodate a large bulk of red-pored boletes is a bold move. The Sutorius tree topology looks weird and very busy.

Yeah, I eventually found…
By: Dave W (Dave W)
2017-03-02 11:54:57 NZDT (+1300)

the intended document… but not at first.

Thank you Igor for your concise answers to my questions.

By: I. G. Safonov (IGSafonov)
2017-03-02 07:37:34 NZDT (+1300)

If you go to
and then click on the “Download full-text pdf” blue button in the upper right corner, the paper will be downloaded to your computer (at least that’s how it works for me — it goes into the downloads folder on the hard-drive). If that doesn’t work, I can email you a copy, but the file is well over 20 Mb in size, so your mail box may not be able to accept it.
The small 2015 paper by Wu et al. just shows Caloboletus as an outgroup, but it doesn’t mean that the two genera sit next to each other.
I didn’t say that your obs 249345 belongs in the genus Pulveroboletus. Wu et al. created this “dust bin” called ‘Pulveroboletus Group’ to accommodate the many genera that they could NOT assign to the seven subfamilies they erected within the family Boletaceae (e.g., Xerocomoideae, Boletoideae, Leccinoideae, etc.). I am not sure why they chose that name instead of something more unique to avoid the confusion with a legitimate genus.

I believe you are correct, Igor.
By: Dave W (Dave W)
2017-03-02 07:02:12 NZDT (+1300)

I had a few free minutes this morning, which is when I read your comment and looked for the paper mentioned in the link. I followed several links from the website and managed to arrive at a different Wu paper than the one you intended (which I believe is the longish paper that includes as extensive phylogenetic tree showing what appears to be at least most of the currently understood species/genera of the Boletaceae). The shorter paper that I briefly browsed includes a small portion of the tree in which Exsudoporus is very close to Butyriboletus (supporting the argument that E should be subsumed into Bu) and Caloboletus calopus not far behind (including a few written comments as per this closeness). The big tree in the more extensive paper does not seem to show this.

As for my reddish/purplish bolete (249345), I guess I’m still having a difficult time assimilating that this is not a Butter Bolete. It’s relationship to Pulveroboletus is also a head-scratcher for me. But I guess Pulveroboletus is now a larger more diverse genus than I would expect from my experience with P. ravenelii. BTW, the location (down to a few square yards) where 249345 was found also hosts P. ravenelii.

Kristine, sorry for hijacking your observation!

By: I. G. Safonov (IGSafonov)
2017-03-02 04:15:00 NZDT (+1300)

Are we looking at the same tree?!
Caloboletus is nowhere near Butyriboletus on the phylogram and both genera are distinct monophyletic clades that don’t have borderline taxa that could be interchangeably placed into one genus or the other. C. calopus is the type species of Caloboletus, so it cannot fall into Butyriboletus.
I see only one sample of Butyriboletus roseopurpureus in the phylogram, voucher MB06-059 — it appears to be very closely related to Butyriboletus pseudospeciosus from Asia.
Lastly, your obs 249345 is not a Butter Bolete — LSU established it pretty well. It’s indeed a resident of the ‘Pulveroboletus Group’, but more sequencing is needed to find out where it falls in the phylogram.

New understandings…
By: Dave W (Dave W)
2017-03-02 02:28:42 NZDT (+1300)

often seem to generate more questions than answers.

I see in the Wu paper that Caloboletus calopus also appears to be a candidate for inclusion into Butyriboletus. I wonder if this may extend to the other species of Caloboletus? As I understand genus Caloboletus (based upon the few species that are found in eastern NA) these species form a nice group of morphologically similar mushrooms. It’d be a bummer if we ended up needing to classify somewhat ambiguous “Caloboletus” material as Boletaceae.

Also, I see on the phylogentic tree there are three varieties of Butyriboletus roseopurpureus. I wonder if this may have implications relevant to some of my collections from last year that were sequenced? obs 249345

News to me as well.
By: Soloist
2017-03-01 18:18:08 NZDT (+1300)

I went for Exsudoporus but MO politely informed me it was deprecated. Have to remeber this now when I post my observations of this gorgeous bolete.

Yes, moved again…
By: I. G. Safonov (IGSafonov)
2017-03-01 17:31:59 NZDT (+1300)

… by Wu et al. (2016):

It’s a fascinating paper showcasing the amazing diversity in the Boletaceae. I cannot take my eyes off those phylograms. :-)

I thought…
By: Dave W (Dave W)
2017-03-01 16:56:37 NZDT (+1300)

this species was now placed in genus Exsudoporus. Has it been moved again?

Looks like there has been another
By: Dave W (Dave W)
2012-06-13 03:57:04 NZST (+1200)

vote of high confidence. This tells me that we can likely rule out the “other similar species” idea. Time to call it “Boletus frostii.”

Flat light
By: Kristine (JanusGD)
2012-06-13 02:56:21 NZST (+1200)

Dave ~ The photo I posted here was shot in flat light – total cloud cover. The colors are actually really accurate. It looked a little more rusty than bright red in color. Beautiful mushroom! I defer to those who know more than I as to what it is :)

Maybe it’s because the photo was taken in direct sunlight…
By: Dave W (Dave W)
2012-06-13 01:46:28 NZST (+1200)

The stipe color is a bit lighter than one may expect.

Also, species of Boletus tend to vary for southern and northern regions on NA. So, based upon my person experience with species of Boletus (mainly PA and point to the north), I find it difficult to rule out that this could be something other than frostii. That’s why I posted at “promising” level of confidence.

Boletus frostii Russell
By: Kristine (JanusGD)
2012-06-13 00:28:53 NZST (+1200)

Thanks for your input Dave. Actually, this specimen was young and very fresh, popped up just after rain and temperature drop.