Observation 97288: Boletus chrysenteron Bull.
When: 2012-06-14
No herbarium specimen

Notes: One of several small boletes found growing under a Scarlet oak.

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ga local
By: GA noiz (ganoiz1016)
2012-08-04 05:05:03 EDT (-0400)

i recently found a specimen that looked exactly like this in Augusta near the Savanna River it bruised blue-green instantly…thanks for helping me identify it

Thanks, Irene and Gerhard!
By: Daniel B. Wheeler (Tuberale)
2012-06-16 14:45:40 EDT (-0400)

I find this fascinating! What I have been calling C. chrysenteron is quite common in my area. Now I will need to put it under a scope and slice it more often.

Most commonly I find it with Douglas-fir (Pseudotsuga menziesii) at Mt. Tabor Park, about 10 blocks away from me. But I also find something similar to this, quite small, probably under 2-inches cap diameter (=5cm) under Quercus palustris in a landscape planting 4-5 blocks away from me adjacent to SE Division street. Have cultivated the material at View, Clark Co., WA and at Jones Creek Tree Farm, Clackamas Co., OR. Most of the material displayed at the Oregon Mycological Society’s Fall Mushroom Show is larger diameter material, maybe 4-5 inches across the cap (10-13cm). Bluing reaction to pores more common with smaller specimens. But maybe they are actually a different species entirely.

I must agree with Gerhard
By: Irene Andersson (irenea)
2012-06-15 13:56:55 EDT (-0400)

I’m not so sure that you have the true chrysenteron here, more likely another species, which I think is closer to cisalpinus. It would be interesting if you could check with Melzers and see if these also have striated spores.

The more common lookalike in Europe growing with oak, is Boletus/Xerocomus porosporus with truncated spores.

Here’s a tree with available DNA sequences of american “chrysenteron” with a couple of other european species added including chrysenteron. Is it possible to talk about a cisalpinus clade in the upper part of this tree..?

X. chrysenteron
By: Daniel B. Wheeler (Tuberale)
2012-06-15 11:16:14 EDT (-0400)

is far-more commonly associated with Douglas-fir in my area. I have cultivated it: i.e., I have introduced it to where it was not found before, and I rapidly found it after introduction. But I have yet to be successful with B. edulis.:( B. zelleri is another easy to cultivate species, but again with Douglas-fir.

So now I just have to figure out what it is I sometimes find with Oregon White oak? Could this be a new species, since it is way outside of Europe?

Sorry to say so
By: Gerhard Koller (Gerhard)
2012-06-15 10:55:58 EDT (-0400)

but I do not consider this B. chrysenteron either. I believe it is an American species of its own close to the chrysenteron group.

Boletus sp ID
By: William Tanneberger (William)
2012-06-15 09:29:35 EDT (-0400)

I was leaning towards the the ID of Boletus cisalpinus due to its appearence and it close association with oak, but I can find no reference of it being found outside of Europe. Boletus chrysenteron looks very similar, but is said to be found with conifers or Beech. It has some reports of being located in Noth America, but I can find nothing for my area (I am located in the Southern Appalachian Mountains of north Georgia). Even though there is a shortage of information, the best fit now seems to be Boletus chrysenteron.

By: Gerhard Koller (Gerhard)
2012-06-15 07:59:33 EDT (-0400)

the taxon was much better known as XEROCOMUS CHRYSENTERON FO. GRACILIS.

By: Gerhard Koller (Gerhard)
2012-06-15 07:58:54 EDT (-0400)

Is it sure it exists in North America? I just know findings from Europe.
It is in most cases smaller than chrysenteron and does strongly bluing on bruising and touching and is found in rather shady places with oak and lime.
Cisalpinus refers to the opposite of transalpinus and means “on this side of the Alps” (stems from the first findings I believe on the Southern side of the Alpine range but it can be found in whole of Europe).

By: Irene Andersson (irenea)
2012-06-15 06:50:42 EDT (-0400)

if chrysenteron exists in North America at all..
One collection from Smokey Mountains named chrysenteron is closer to cisalpinus. I’m not sure if it’s close enough to be the same, though.

Might also be B. chrysenteron
By: Daniel B. Wheeler (Tuberale)
2012-06-14 19:57:02 EDT (-0400)

which I have rarely found associated with Quercus garryana (Oregon White oak). Photos suggest an older specimen, as the cap is nearly planar. I am unfamiliar with B. cisalpinus. Doesn’t the scientific name suggest a high elevation fungus: cisALPINUS?

Maybe Boletus cisalpinis, since it was found growing under an oak tree.
By: William Tanneberger (William)
2012-06-13 20:54:15 EDT (-0400)

Found following reference, but could find no image.

“Xerocomus cisalpinis is very similar and the two species are most easily distinguished by habitat. X. cisalpinis grows exclusively with Oak whereas X. chrysenteron is found with conifers or Beech”.

Xerocomus cisalpinis = Boletus cisalpinis
CORRECTION FOR ACCEPTED NAME: Boletus cisalpinis > Boletus cisalpinus

Created: 2012-06-13 20:11:05 EDT (-0400)
Last modified: 2012-06-15 09:30:36 EDT (-0400)
Viewed: 322 times, last viewed: 2016-10-20 21:21:15 EDT (-0400)
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