Observation 311827: Boletaceae Chevall.

When: 2017-08-10

Collection location: North Park, Allegheny Co., Pennsylvania, USA [Click for map]

Who: Dave W (Dave W)

No specimen available

Growing in an area with spread wood chips. Tree closest to the mushrooms was black gum (Nyssa sylvatica), oak about 10 yards away.

Mushroom with blue bruising on the tubes was likely damaged in-situ by a grass-cutting crew.

Ribbed stipe surface and bright yellow young pores remind me of X. subtomentosus. But the caps appear to be glabrous, and the blue bruising on the damaged pores is intense for subtomentosus.

6th photo… the stipe appears to lack ornamentation (at least to the extent of the others), but otherwise looks to be the same type; found in the same wood chip area. May be the same mushroom as the one seen in the 4th photo down. Last photo… stipe ornamentation raised threadlike.

Cap widths 1"-3".

Proposed Names

58% (1)
Eye3 Eyes3
Recognized by sight
28% (1)
Recognized by sight
Used references: See discussion below

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Dave W (Dave W)
2018-03-19 07:19:17 CDT (-0500)

it’s impossible to adequately get a point across in a few well-chosen words. With these boletes, there’s always so much to discuss… subtle traits, name changes. BTW, I think we may have arrived at a reasonable genus name for this one… Pulchroboletus. The discussion leading to this may take awhile to read. But it’s a whole lot better than just having a list of names/votes/confidence without a supportive discussion. Mushroom ID is often a group effort.

By: I. G. Safonov (IGSafonov)
2018-03-18 12:18:38 CDT (-0500)

Your line of questioning didn’t nauseate me; it never has. :-)
The feeling is more self-induced, as I tend to write too much (TMI) for my own good, while realizing at the same time that repetition (review) is the mother of learning. Just remember that sclerotiorum is not in Xerocomus. Perhaps penciling in a comment in your personal copy of BENA will help. :-)

Igor, thanks for the clarification..
By: Dave W (Dave W)
2018-03-18 10:35:44 CDT (-0500)

on the cap context/tube-layer ratio. I was misreading “1.5-3” as “1.5/3”. So, yes, in Lanmaoa the cap context may be as much as 3x the thickness of the tube layer… >>3x in an immature fruit body.

Sorry for inducing nausea with my line of questioning :-( But, I don’t read every MO discussion, and the ones that I do read… I don’t claim the ability to store/recall every detail. This bolete taxonomy stuff is difficulty to keep up with. Some of us benefit from the occasional review :-)

By: I. G. Safonov (IGSafonov)
2018-03-17 20:48:14 CDT (-0500)

Yes, as we know, bluing is a very variable feature even within a species, so eliminating B. pallidoroseus based on this trait alone is certainly questionable. However, in my experience, the flesh of B. pallidoroseus (particularly in the stipe) doesn’t stain blue heavily; as a matter of fact, the staining of cut flesh if any, is very patchy and usually light, just like in B. bicolor. Here, the cracked stipe flesh of the in situ damaged specimen shows uniform and pronounced bluing. The flesh here is also very fibrous and friable, unlike that of pallidoroseus, which is very firm throughout when young and becoming like a moist marshmallow with age in the cap. The color scheme of this bolete (particularly lack of dominant rose red in the stipe in young fb) and low the cap flesh thickness /tubes depth ratio (< 3:1) suggest it’s not pallidoroseus. The latter feature also points away from Lanmaoa.

Sorry about the confusion with the ratio of cap flesh thickness to tube layer depth. Baorangia and Lanmaoa are both characterized by short tubes relative to the cap flesh thickness, meaning that the ratio is usually a number above 3 and below 10.
There are ways of measuring the ratio. For example I divide the cap thickness measured in the cap center from the cuticle to the imaginary line drawn at the juncture of the stipe with cap by the maximum depth of the tube layer. The 2015 Wu et al. paper that introduced the two aforementioned genera measures cap thickness midway between cap edge and cap center. I don’t know which would be the preferred method.

Regarding sclerotiorum, it doesn’t belong in Xerocomus as per the existing DNA data generated by Dr. Kudzma for my modest sequencing effort. Instead, it appears to be closely related to Pulchroboletus rubricitrinus. However, phylogenetically Pulchroboletus is a bona fide member of Xerocomoideae (Wu et al., 2014 & 2016).
To date, my personal experience with sclerotiorum is still limited, as I have only seen it a handful of times in the flesh (e.g., 243879 & 288112 lately). It is commonly found in the Atlantic coastal plains from TX to at least NJ. There is a genetically related morphological doppelganger I dubbed “pseudosclerotiorum” (e.g., 215764 & 286328) that so far has been found more inland. All of this has already been discussed ad nauseam in these observations.

I noticed that Xerocomus sclerotiorum…
By: Dave W (Dave W)
2018-03-17 19:31:14 CDT (-0500)

matched up for some of traits, in particular the longitudinally striate stipe. Although genus Xerocomus has been discussed and pores/tubes seem to point away from this, I think it’s not out of the question. I’m not familiar with X. sclerotiorum (except for the account in Boletes of ENA). Do the pores/tubes typically bruise as prominently blue as is seen with this observation?

Remind me of x.sclerotiorum
By: dario.z (dario13)
2018-03-17 15:53:32 CDT (-0500)
Not sure about…
By: Dave W (Dave W)
2018-03-17 10:16:14 CDT (-0500)

the intensity of the bluing being a reason to eliminate pallidoroseus from consideration. This trait seems to be variable for pallidoroseus. One of the photos in NAB shows very dark blue bruising on the pores.

I think the ornamentation on the stipes (raised more-or-less vertical ribs) is the really interesting feature with this observation. It’s why I initially thought Xerocomus may apply. But, I have some cross-sectional photos to post showing tubes that appear to be neatly-packed and probably separable. The new photos show the mushrooms possibly more than one day after being collected. The brown stain seen on the tubes is presumably an area that had bruised blue and then resolved to the brownish. This is a trait I associate with Lanmaoa (although there are likely other types where the blue changes to brown).

Looking through the Bessete bolete books, I see (Boletus/Pulchroboletus/?) rubricitrinus is a red/yellow bolete with a ribbed stipe.

Igor, I may be a bit confused about the context/tube thickness ratio (in the cap) that you mentioned (I think in relation to genus Lanmaoa). Here is part of what you wrote, “…low cap thickness to tube length ratio of only 1.5-3…”. Is this to say that the thickness of the tube layer is twice that of the layer of context above the tubes? My own concept of Lanmaoa pseudosensibilis is that the tube layer is very thin, at least in youngish specimens.

I have also added a photo of leaves from the nearest tree (IDed as Nyssa sylvatica). Also, the person who made the collection(s) is not certain about the passage of time encompassing the occurrence of these mushrooms… sometime between 7/23 and 8/10… possibly more than one collection date.

Yes, John
By: I. G. Safonov (IGSafonov)
2018-03-16 23:38:49 CDT (-0500)

It seems like were are all fishing in Lanmaoa for this critter. Indeed, pallidoroseus is likely to fall there, too, based on some preliminary DNA testing (see my posts for this taxon, aka L. pallidorosea comb. prov., here on MO). Alas, too much bluing for pallidoroseus in this case!

This reminds
By: John Plischke (John Plischke)
2018-03-16 22:11:22 CDT (-0500)

This looks a little like some of the Boletus pallidoroseus I see there

By: I. G. Safonov (IGSafonov)
2018-03-14 17:51:22 CDT (-0500)

Smith & Thiers put this taxon into stirps sensibilis (see key on p. 271 of TBoM), which is polyphyletic as per the contemporary phylogenetic treatment. One important detail, however, stands out — it shares the stirps with miniato-olivaceus and four other taxa currently in Lanmaoa: bicolor var. borealis, carminipes, pseudosensibilis and sensibilis (the last one is a provisional placement). However, this association of the taxon in question could be artificial for all we know.
The TBoM concept is that of a very large bolete with fairly long (12-16 µm) spores and a low cap thickness to tube length ratio of only 1.5-3. Smith & Thiers say it’s most closely related to sensibilis morphology-wise. If one accepts the fact that Lanmaoa taxa are characterized by a 3-5 ratio of pileal thickness (measured half-way to the cap center) to tube length, miniato-pallescens is certainly an outlier in that regard.

Stipe ornamentation…
By: Dave W (Dave W)
2018-03-14 12:54:10 CDT (-0500)

is also why I didn’t give serious consideration to Butyriboletus.

Right… Whatever the NAB “miniato-pallescens” taxon is, it’s possibly/probably a Lanmaoa. Forgot about that. So, Lanmaoa makes sense here.

Yes, I doubt the wood chips have anything to do with these mushrooms… except for maybe helping to retain moisture.

By: I. G. Safonov (IGSafonov)
2018-03-14 11:39:08 CDT (-0500)

I didn’t think it was any of the taxa both you and I mentioned.
I didn’t even consider Butyriboletus, for the stipe ornamentation in this collection is not consistent with it.
My current concept of sensibilis is represented by obs 280056 and obs 288555.
I don’t know what mushroom in the east coast would currently represent miniato-pallescens. What BENA shows for that species appears to be a taxon with the morphology consistent with it being a Lanmaoa species. When we had only NAB at our disposal, many proposals on MO were critters in the sclerotiorum group. Like many of the other Smith & Thiers species featured in their TBoM for the first time, this taxon will continue to be a mystery indefinitely. Perhaps it’s a species endemic only to that part of the country.
Lastly, I doubt the wood chips have anything to do with the mushroom’s habitat requirements.

Nice detective work, Igor.
By: Dave W (Dave W)
2018-03-14 08:28:07 CDT (-0500)

These photos are indeed the work of someone other than me. They were posted onto another mushroom discussion board by the person who found the mushrooms. I thought this collection was interesting, so I asked the collector if it would be okay for me to create this MO observation.

I also considered a sensibilis ID, but the stipe looks way wrong for sensibilis, and the cap also looks off for this species. I doubt this is miniato-olivaceus; way too much staining and the caps are uniformly reddish; also no hemlock in the area, which seems to be the main mini-o associate. Maybe miniato-pallescens…?

Gestalt seems off for either Lanmaoa or Butyriboletus. Presence of decomposing wood seems to suggest Xerocomellus, but this doesn’t look right to me. These mushrooms seem too robust for Hortiboletus. Aside from the strong bluing and rather glabrous cap surface, X. subtomentosus seemed to make the most sense. Cap color is quite variable for the subtomentosus types. Oak reported in the habitat.

Hey, Dave
By: I. G. Safonov (IGSafonov)
2018-03-14 01:15:08 CDT (-0500)

A rather unusual observation for you. First, the location itself is kinda out of your way, but – judging from the date – you could have been taking a detour upon your return from NEMF. Then way the pix were taken doesn’t evoke your well-established style that you follow consistently for boletes, which makes me think you probably didn’t take them. That latter notion is supported by the pix metadata, for it doesn’t appear to be your regular camera. Okay, enough of the deduction business. :-)
As of the mushroom, just like you I am drawing a blank, though I don’t think it’s in Xerocomus. However, the overall gestalt, particularly the color scheme and the pore surface with its color and the tiny pores at maturity seem to point toward some entities that could actually wind up in Xerocomoideae — for example, taxa like B. miniato-olivaceus and its western relative B. smithii; “X.” sclerotiorum and its look-alike (e.g., 215764 & 286328), both of which could fall into Pulchroboletus. Another possibility is something in Lanmaoa – I think sensibilis is likely a member of that genus based on preliminary genetic tests.
If you saved this collection, I could put it into my 2018 sequencing queue.

Created: 2018-03-13 22:30:48 CDT (-0500)
Last modified: 2018-03-19 07:19:17 CDT (-0500)
Viewed: 216 times, last viewed: 2018-04-04 22:22:40 CDT (-0500)
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