Solitary specimen in opening near a stream bank in hemlock-dominated area, with white pine and oak in the vicinity.

Cap vivid purplish red, diameter around 7 inches, margin wavy/firm.

Pores yellow bruising grayish-blue, and in some areas brownish.

Stipe about 2.5 inches diameter, yellow with wide/coarse reddish-brown reticulatum becoming a reddish-brown coating on the lower half. Base with yellow mycelium dotted red.

Context whitish in cap, yellow in stipe with yellow areas, stained red near worm holes. All context staining slowly and fairly faintly blue when cut.

Ammonia: green flash becoming orange on cap, pale lemon yellow on context.

KOH: vivid orange on cap surface, yellowish-orange on cap context, muddy orange on stipe context.

Undamaged portion sliced and dehydrated.

A magnificent sight from 80 feet away.

I returned to this spot 4 days later, after a heavy rainfall, and there were three additional (smaller) specimens in the same 50 square yard area.

Species Lists


Copyright © 2020 I. G. Safonov (IGSafonov)
Fig.1 RPB-2 phylogram of MO249345
Copyright © 2020 I. G. Safonov (IGSafonov)
Fig.2 TEF-1 phylogram of MO255258 (conspecific w/ MO249345)

Proposed Names

28% (1)
Recognized by sight: Unusual combination of morphological characters.
The same species was collected by Dave on a few more occasion from this location — see obs 250964, obs 250967, obs 250978, obs 250979, and obs 250980.
Based on chemical features: nrITS and nrLSU sequences don’t match anything even remotely in GenBank
56% (1)
Used references: TEF-1 & RPB-2 phylogenetic trees posted to this observation

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

= Observer’s choice
= Current consensus


Add Comment
Here’s another observation…
By: Dave W (Dave W)
2020-03-03 07:50:48 CST (-0500)

of this same species made in the same location as 249345, obs 250967. The staining on the sliced context of 250967 is also much less prominent than what is seen at obs 302111. Also, the stipe ornamentation on the Ricketts Glen specimens is different than 302111.

I don’t think so
By: I. G. Safonov (IGSafonov)
2020-03-03 01:51:13 CST (-0500)

Too much bluing, for one. The species Dave’s critter represents slowly stains bluish-gray (slate), and this quality is one of the defining features of this taxon. Also, yours has very shallow tubes, perhaps suggesting Lanmaoa. Thoughts?
It would be nice if you could find it again.

Could this one be the same
By: John Plischke (John Plischke)
2020-03-03 01:39:48 CST (-0500)
By: I. G. Safonov (IGSafonov)
2020-02-26 12:24:10 CST (-0500)

it’s a coincidence, of course. Your obs 382023 looks a bit weird, but it generally fits the gestalt of R. vinaceipes. I see you have the voucher, so, if necessary, its identity can be established by sequencing.
The placement of the present species (MO249345) into Leccinoideae is tentative, as the GB trees don’t show statistical support numbers (ML bootstraps and/or Bayesian posterior probabilities). However, I spent a bit of time with the tree-building, and this critter repeatedly claded in a separate branch next to Retiboletus regardless of the choice of other accessions. In other words, it didn’t ‘want’ to be part of the other subfamilies in Boletaceae.
I will look into running this RPB-2 data set (i.e., the same choice of GB accessions) through another program in that shows support stats to see if I can get a matching/similar inference and gross topology.

No sure if there’s any relevance…
By: Dave W (Dave W)
2020-02-26 08:15:52 CST (-0500)

but seeing as this mushroom appears to represent a taxon that is related to genus Retiboletus, perhaps the following is of some interest. This mushroom (MO249345) was collected from a location very close to where I collected obs 382023. Also, I recall another collection made in this location (less than one acre total).

RPB-2 sequencing [edited]
By: I. G. Safonov (IGSafonov)
2020-02-25 20:43:18 CST (-0500)

> A clean a contiguous RPB-2 sequence of 766 bps was obtained by Dr. Kudzma from this collection. The sequence is almost fully supported by two quality reads, and covers the region exactly between bRPG2-6F3 and bRPG2-7.1R primers that were seen but edited out. There is only one intron in this stretch of the gene and it’s located at the very end of the sequence. There are two ambiguous characters present: “R” (A/G) and “Y” (C/T).
> A phylogenetic tree was built in GenBank from 50+ relevant accession chosen from a BLASTn-500 search of this sequence and uploaded to this observation. It’s a good-looking tree, as topological monophyly was achieved for 5 subfamilies of Boletaceae and all 19 genera that comprise them. MO249345 is shown to clade in the subfamily Leccinoideae as a sister monotypic genus to Retiboletus.
> I have also uploaded a phylogram derived from the TEF-1 sequence of Geoff Balme’s obs 255258, which is conspecific with MO249345 by virtue of matching ITS-LSU data. The overall topology seen here is in excellent agreement with that of the RPB-2 tree.
> In the recent paper by Kuo and Ortiz, the subfamily Leccinoideae , the primary focus of this research effort, is moderately supported by the statistical analyses of the 3-loci data sets.1 Within Leccinoideae, the authors identify 6 monophyletic subclades. Based on the strong statistical support shown in their analyses (96/1), the authors propose a phylogenetic collapse of Leccinum s.s., Leccinellum, which was found to be polyphyletic, 4 genera of exotic sequestrate fungi, as well as several other ‘leccinum-/leccinellum-esque’ taxa, into a broadly-defined genus Leccinum.
1 Kuo and Ortiz-Santana, “Revisions of leccinoid fungi, with emphasis on North American taxa, based on molecular and morphological data”; Mycologia 2020, 112(1), pp. 197-211.

Yes, Dave,
By: I. G. Safonov (IGSafonov)
2017-04-26 23:46:59 CDT (-0400)

there is some reticulation in obs 255923, but it’s nowhere nearly as noticeable or striking as in this and your other collections of this gorgeous bolete from Ricketts Glenn.
The overall condition of 255923 left something to be desired as it popped up around the time the Raleigh area got inundated with tropical storm Matthew. It was the color of the cap and the wavy cap margin that eventually pointed to the similarity between the two collections.

Thanks for the update Igor.
By: Dave W (Dave W)
2017-04-26 22:47:44 CDT (-0400)

My collection seen here and Geoff’s obs 255923 have similar appearance… color, stature. Looking closely at Geoff’s, I see some wide reticualtion on the stipe.

By: I. G. Safonov (IGSafonov)
2017-04-26 22:29:46 CDT (-0400)

See Geoff Balme’s obs 255923 for an interesting revelation regarding your collection.

Thanks for the work, and the report, Igor.
By: Dave W (Dave W)
2017-01-03 17:09:48 CST (-0500)

I guess it’s not a really big surprise this fails to match existing sequences. There are also key morphological traits that fail to match up with anything.

I’ve got a few collections of this species preserved.

DNA sequencing discussion
By: I. G. Safonov (IGSafonov)
2017-01-03 15:12:16 CST (-0500)

A clean and contiguous nrITS sequence (472 bps long, the shortest ITS I’ve seen in a bolete so far!) and an equally high-quality nrLSU sequence (1445 bps long) have been procured for this collection and uploaded to this observation.

GenBank BLAST search of the two sequences did not recover any close matches or meaningful hits and hit patterns. As a matter of fact, there was nothing closer than 91% similarity for ITS (horrendous!) and nothing closer than ~97% for both full-length LSU sequence and fragment 1—>961 (equally meaningless to draw any conclusion about possible generic affinities). So, while this entity is now fully barcoded/“fingerprinted”, Boletaceae is still as accurate of a name as one can apply to it. One thing for sure, it’s not a member of the Butter Bolete clade. Looks like, Dave, you got yourself a very, very unique bolete! :-)

In case you didn’t know, Dave, ITS and LSU actually form a continuous string with no interruptions/insertions between them, i.e. ITS ends with …GGTTGTCTAC and LSU immediately begins with the conserved TTGACCTCAAATCA motif.

Well, John,
By: I. G. Safonov (IGSafonov)
2016-09-04 22:51:13 CDT (-0400)

when there are lots of fungi in the woods, stuff gets left behind all the time. Sometimes the baskets are so full there isn’t enough time to process and photograph and process every collection. In that case stuff gets inevitably thrown away. I certainly understand your frustration of forgetting about an interesting collection because of being distracted by the fungal bonanza. However, I would rather have that kind of frustration than the one that has to do with leaving the woods with a practically empty basket (hint: that’s me in the last 30 or so days). :-)

Posting subsequent observations now.
By: Dave W (Dave W)
2016-09-04 22:50:07 CDT (-0400)

I think the faint bluing on the cut context, although atypical of roseopurpureus, can be reconciled with this species. But the flesh of this mushroom was mild, and subsequent collections from the same small area also tasted mild, actually pleasant. Also, the blue bruise on the pores morphed into a brownish color. So, this seems to be stretching the roseopurpureus concept, at least as outlined in NAB.

By: John Plischke (John Plischke)
2016-09-04 22:33:00 CDT (-0400)

I don’t have the 2 that I found. I just went and cleaned out my basket and put a few on the dehydrator for now and they got left behind. I have been thinking about going back to get them because I know exactly where I left them when we were repacking our overfull basket but the park is a couple hours away and it would be 1230 before I could get there and I am to tired. Hopefully Dave will have other photos. I know the spot where I saw them so I can always check another time for more. I really thought these were strange and took them out to photograph them but then saw some Austroboletus gracilis and a few others that I photographed and somehow I left them behind in the woods with out a photo, I am so disappointed.

By: I. G. Safonov (IGSafonov)
2016-09-04 22:10:59 CDT (-0400)

This giant looks amazingly fresh and solid. It doesn’t appear the weather had anything to do with the “atypical” morphology. We are still waiting for Dave to post the other, young fbs from this collection. Anyway, if you put it on your priority sequencing list, we can probably have the answer by the end of the year. :-) Recall that ITS worked very well for Bytyriboletus (Arora and Frank, 2014).

The more
By: John Plischke (John Plischke)
2016-09-04 21:56:38 CDT (-0400)

The more I think about it the more I a leaning to roseopurpureus. When I found identical looking ones today I first thought a weird bicolor with a purplish cap. Then I thought roseopurpureus, but they did not look quite right. Now that I think about it, last year in the same exact area I did photograph a typical roseopurpureus. I bet these are just atypical forms that the sun and weather did a trick on.

I saw 2 of theses today
By: John Plischke (John Plischke)
2016-09-04 21:43:41 CDT (-0400)

I saw 2 of these today. I did not have a clue but big thick mushroom with purplish tones on the cap, I just checked my camera card to see if I had a photo and I forgot to take one. I was carrying them around for 4 hours today trying to find a third one for the photo. I will ask kim is she got a photo. We dumped the basket getting the final shots and I don’t know why they never got put back.

By: Dave W (Dave W)
2016-08-24 21:56:48 CDT (-0400)

every now and then I fall victim to applying ultimate confidence to an ID for which I have no previous first-hand knowledge. I agree, Igor, since there are a couple traits that don’t match the recorded description of roseopurpureus, I should begin from a more conservative perspective.

But this mushroom appears to match roseopurpureus better than anything else in NAB. Something like this, big and showy; one would expect there to be a readily available category.

Post of subsequent similar/same species is forthcoming. I have a few others to get through first.

The more…
By: I. G. Safonov (IGSafonov)
2016-08-24 12:57:39 CDT (-0400)

…I look at the pictures, the less I am convinced this is B-b.roseopurpureus, though it may still be a member of Butyriboletus. According to NAB, that particular Butter Bolete is an all yellow mushroom with exception of the cap. Occasionally, the stipe base can be flushed with burgundy. Your mushroom, Dave, has a lot of red in the stipe, even closer to the apex, and the reticulation is red, too. If the young buttons you mentioned have the same properties, then IMO an alternate ID should be strongly considered. At any rate, sequencing the ITS or LSU genes should bring at least some clarity to the identity of this beautiful and impressive bolete.
I don’t think B. speciosus has been transferred to Butyriboletus yet (lack of reliably identified vouchers perhaps?), but it seems like a good candidate for this eventuality.

The gestalt of this mushroom…
By: Dave W (Dave W)
2016-08-24 11:44:58 CDT (-0400)

seemed a bulls-eye for roseopurpureus. But you are correct, Igor. The slow fairly faint staining on the cut context fails to match the NAB description. One alternative would seen to be speciosus (has this been moved to Butyriboletus?). But this species is also reported as a strong stainer.

I collected another of these yesterday, same location, will post. This new one also exhibited the slow fairly faint bluing on the cut context. Taste (just sampled) is slightly lemony at first, with a mild/sweet finish. But I would not describe the taste as “sour”, which is what NAB says about roseopurpureus.

Looks like this may be more interesting than I first thought. A significant portion of this fb has been dehydrated. I left a couple buttons in-situ.

Alternative ID?
By: I. G. Safonov (IGSafonov)
2016-08-24 01:14:55 CDT (-0400)

Lack of rapid and vivid bluing and the presence of red reticulation actually point away from B. roseopurpureus. How did the flesh taste?