Please do not re-click a link while waiting for a page to load. (It’s slower and degrades site speed for all users.)
To get images for machine learning, see MO Images for Machine Learning


When: 2013-09-27

Collection location: Jamison City, Pennsylvania, USA [Click for map]

Who: Dave W (Dave W)

No specimen available


Proposed Names

87% (1)
Recognized by sight: Staining pattern on cut context.

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

= Observer’s choice
= Current consensus


Add Comment
Thanks for the input, Igor.
By: Dave W (Dave W)
2013-09-30 19:00:32 CDT (-0500)

Sounds like oxydabile and holopus are potentially confused. B/R/B does not even report any macro-chemical tests for oxydabile. I’m pretty sure the specimen seen in this obs represents snellii. I have IDed lots of snellii form this same exact location. It seems to be the dominant Leccinum in this well-drained hardwood forest.

I’m now a bit more motivated to analyze some of my alleged holopus/snellii collections… with oxydabile in the back of my mind.

Hello, Dave:-
By: I. G. Safonov (IGSafonov)
2013-09-30 13:21:07 CDT (-0500)

I am just trying to throw an idea around based on a single picture you provided and what I was exposed to at the Bessette workshop in Maine earlier this month. I got more exposure to the genus Leccinum in a few days spent in Maine than in my entire 8 years of actively collecting mushrooms in NJ. L. oxydiable, as well as L. holopus, that both prefer wet, boggy habitats, were the two most commonly found Leccinum species there at the time and both were new to me, so they left at least a short-term mark in my brain.
I was never fond of dichotomous keys, but thanks to them identification of Leccinum species through B-R-B became a less onerous task. As a matter of fact, they do work very well. We had several group exercises on bolete unknowns, and the keys always led us to correct answers for species I had already been familiar with.
Of course, our current understanding of this genus in North America will eventually be re-shaped by DNA studies, so who knows how many Leccinum species listed in B-R-B and other contemporary literature will survive that test.
I think that staining patterns/intensities are even less reliable than macro-chemical tests for identification to species and should be interpreted with caution. For example, B-R-B shows a pictorial example of L. oxydiable exhibiting only pale staining of the exposed flesh. I can also show you a picture of a recent specimen from Maine (forwarded to me by the Bessettes) with enough red on the entire oxidized surface to overload your retina. On the other hand, I don’t know if color transitioning is something that is necessarily preserved within each species. Habitat, indeed, is an important factor, and based on that L. snellii is a much better fit for your specimen.
Finally, B-R-B does a great job in differentiating between scabrum_/snellii_/oxydabile/holopus and other, if any, brown-capped species whose flesh turns first some shade of red upon oxidation, so arriving at an unambiguous ID isn’t that complicated.

Hi Igor.
By: Dave W (Dave W)
2013-09-30 07:37:06 CDT (-0500)

The staining pattern in this specimen is not as dramatic as what I generally see in ones IDed as snellii. The area where I collected this produces lots of specimens of snellii, so that influences my thinking here. I don’t have my bolete book here with me at the moment. But one online source reports “spruce and scrub birch” as the habitat for oxydabile. The area where I found this, mixed hardwoods including plenty of mature birch, does not have any spruce.

Very dry conditions preceding time of collection. I’m wondering if this could affect the staining pattern.