Boletus oliveisporus is getting posted again… because this particular collection is heavily reticulated — something I haven’t observed in the past. Other than that, I cannot visually distinguish this collection from other numerous collections of B. oliveisporus I have made in the past in the NJ Pine Barrens.
It’s a beautiful species with exceptionally dense flesh, and it always comes without a single larval tunnel. Though Texas Mushrooms: A Field Guide by S. & V. Metzler reports this species as edible, I am still waiting for avid bolete consumers to report on the edibility of this profuse blue-stainer.


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By: Jason Bolin (
2017-10-29 06:03:46 NZDT (+1300)

I would buy that var. except I have seen a cluster of B. luridellus growing out of the same base, some heavily reticulate, some not reticulate at all :)

Thanks, Arleen
By: I. G. Safonov (IGSafonov)
2017-10-29 05:27:48 NZDT (+1300)

Indeed, a very groovy stipe. :-) I wonder if it’s some kind of developmental anomaly, but more than one fruiting body are affected. Boletus oliveisporus var. reticulatus, anyone?

To reticulate or not…
By: Arleen Bessette (MsMucor2)
2017-10-29 04:42:30 NZDT (+1300)

Yep. It is B. oliveisporus in our opinion. We have seen specimens totally lacking reticulation to being reticulate at the apex only, to some reticulation extending further down the stipe. Your’s, Igor, wins the best dressed stipe for one we have yet to see! “Keen!”, as a dear friend would say.

By: I. G. Safonov (IGSafonov)
2017-10-28 19:05:13 NZDT (+1300)

Oliveisporus is not supposed to be reticulated, but the most recent description (in BENA) says “…sometimes reticulate on the upper portion, conspicuously longitudinally striate”.
This is the only time I saw it like this. Yes, I know, it makes you wonder if it’s something else, but all the other macro-morphological features of this collection fit the oliveisporus gestalt.
I dunno… maybe it’s worth getting it sequenced just in case, but I don’t see it as a priority right now.

By: Jason Bolin (
2017-10-28 17:33:33 NZDT (+1300)

I have not read the original description of B. oliveisporus but I am surprised to see reticulation this raised and course, or present at all. Reticulation is typically a defining feature. I would be just as surprised to see an example of T. felleus that lacked reticulation.

Yes, Jason, why not?
By: I. G. Safonov (IGSafonov)
2017-10-28 17:07:45 NZDT (+1300)
B. oliveisporus
By: Jason Bolin (
2017-10-28 16:49:36 NZDT (+1300)

A heavily reticulate B. oliveisporus??

By: I. G. Safonov (IGSafonov)
2016-08-19 05:13:25 NZST (+1200)

The green box is not mine. The cross-section was done at home. I have a green waffle towel, but the color is not as “poisonous”. I will make sure to use in mushroom photography next time… just for you. :-)
Yes, the reticulation is very unusual, especially when NAB/BRB states black on white “lacking reticulation”. We found other reticulated collections of this species on that day, but the netting was not as heavy.
No chemical tests — this is a well-known, firmly IDed taxon from the Pine Barrens. I had it sequenced last year (obs 208605) and found a 100% match in GenBank.

By: I. G. Safonov (IGSafonov)
2016-08-19 05:00:25 NZST (+1200)

Don’t get obsessed with the colorful display of pigments in boletes’ stipe base and certainly don’t allow your nascent obsession to develop into a fetish. :D
I don’t really know much about the chemistry/biochemistry behind the color transformations and frankly I don’t particularly care about it either. It’s too complicated and not much useful in identification in the field… especially for those of us who didn’t do well in organic chemistry in college. :-)
There is a paper on bolete pigments from a few years ago. I read it a while back, walked through the reaction mechanisms and had a general understanding of the functional group transformations. The molecules are all aromatic compounds in the neutral or anionic state, with extensive double bond conjugation. In essence, they are dyes. It was fun to “push the arrows” and follow the flow of electrons in the chemical structures, but so what? Noting any interesting trends in the way a species stains and connecting the dots is of import though.
As of the cross-section picture, there is actually no red at the base/root — it’s just dark brown. The flash is responsible for the red-shift. The mushrooms spent at least 24 hrs in the fridge and when I cut them, the flesh was still cold.
The context of B. oliveisporus stains blue instantly, but the color is never as dark as in C. pulverulentus or B. subvelutipes. What’s more interesting is that almost immediately, the blue begins to change to brown, from the stipe base up, with the color intensifying over time. In just a few minutes the flesh is all brown. As far as I know the only other bolete that exhibits a similar color transformation is L. pseudosensibilis.

By: Robert(the 3 foragers) (the3foragers)
2016-08-19 03:26:48 NZST (+1200)

The green is screaming!
It is strange it has such a reticulation. Did you do some chemical tests?
Back to the green background. why not be consistent and take the cross section under green tooooo ?

I’m getting obsessed with the inside of the stipe base on recent finds.
By: Scott Pavelle (Scott Pavelle)
2016-08-18 11:58:03 NZST (+1200)

This one also seems to have red in the underground parts, and to stain progressively darker as you move downward. My (quite limited) memory says that is not unusual, but also that I’ve seen no explanations.

Can you expand on that? I speculate that it must have something to do with the natural concentration of variegatic and other acids that are responsible for both the natural red in boletes (when oxidized by air) and the bluing (when oxidized in the presence of enzymes that are also in the flesh). I’m kind of proud that I could make that connection, but it is the very outermost extreme of my knowledge. I’d love to hear more informed thoughts.

By: I. G. Safonov (IGSafonov)
2016-08-09 09:12:07 NZST (+1200)

Thank you, Scott. Yes, the picture came out good, but it won’t win me any awards. Besides, Robert will complain about the “poisonous” green background as usual. :-)

By: I. G. Safonov (IGSafonov)
2016-08-09 09:08:54 NZST (+1200)

Yes, I just saw John’s pic on the Bolete Filter, but my reticulation is better than his. :-)
By the way, none of the descriptions for this species (e.g., NAB, Mushroom Expert, Texas Mushrooms) call for reticulated stipes. Must be some kind of developmental anomaly, I guess. Just in case, I have preserved this collection.

FWIW, JP3 has a photo with heavy reticulation…
By: Scott Pavelle (Scott Pavelle)
2016-08-09 08:57:14 NZST (+1200)

…at the Bolete Filter. So it may be an unusual feature for your area, but it’s not outside the “norm” for the species in general. This is a lovely pic too. Could be in your personal top-10 from the art-only point of view.