Observation 140023: Xerocomus hortonii (A.H. Sm. & Thiers) Manfr. Binder & Besl

Proposed Names

58% (1)
Recognized by sight: Looked like Boletus hortonii until I turned it over.
58% (1)
Recognized by sight: Also saw this “variety” at the WV foray last year

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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The links provided by Christian…
By: Dave W (Dave W)
2016-03-23 08:42:38 EDT (-0400)

are apparently based upon “MO Image #s”, a mistake I have also made. The observations appear to be obs 88231 and obs 139748.

I have one dependable hortonii spot, but I have never seen the reticulate stipe on this type.

Time to change my observations proposals on hortonii.

Weird hortonii
By: I. G. Safonov (IGSafonov)
2013-07-16 15:15:23 EDT (-0400)

Wow! I’ve seen a fair share B. hortonii over the last few years at various forays in NJ and out-of-state events like the NEMF, but none had reticulated stipes, not even at the apex.

The severely corrugated (not just pitted) cap of B. hortonii is a rather distinct and unique feature, undoubtedly coded for by the DNA. It might have been a common mutation in a certain population(s) of B. subglabripes_, or an ancestral precursor thereof, given the fact that the two mushrooms are otherwise very similar in appearance (not sure if DNA studies confirmed or disproved that).

Reticulation in boletes on the other hand, as I understand, is a developmental feature that is also programmed by the DNA. However, since development is also subject to environmental factors, there could be an appreciable degree of variability in the way reticulation (or other phenotypic characteristics, such as size and shape of fruit-bodies) is expressed in multiple specimens of a single collection.

In the case of No. 140023, the stipe is devoid (as far as I could see) of the typical scruffiness/pruinosity associated with the “leccinumesque” boletes, and is instead prominently reticulated. Its stipe almost reminded me of R-b. ornatipes (the color and reticulation). I think that environmental factors could be excluded, given the degree to which the reticulation is expressed here, meaning that this is likely to be a mutation in this population of B. hortonii.

It would be nice to get Walter’s “mutant” sequenced and compared with both subglabripes and hortonii. Could be a new species or subspecies. :)

P.S. I am sure that everyone who commented on this obs have already thought of this, and I just happened to take the time to express this idea.
P.P.S. The two obs mentioned by Christian don’t exist.

almost Hortoni…
By: Bill (boletebill)
2013-07-16 14:02:09 EDT (-0400)

…strangely enough last Sunday we collected a bunch of these B. subglabripes type pseudo hortoni at our weekly foray. The caps had a mild hortoni-like corrugation and some had a very fine reticulation at the apex but not the extent shown here. I find reticulation at the apex of the stipe to be extremely variable in many Boletes in the genera Tylopilus and Boletus. This year I’m finding boletes I’ve never seen before OR variations in boletes that I have seen before that are atypical, as in Walt’s reticulated hortoni here.

By: walt sturgeon (Mycowalt)
2013-07-15 18:42:29 EDT (-0400)

going on the dryer tonight.

By: Christian (Christian Schwarz)
2013-07-15 18:18:02 EDT (-0400)

Wow! Crazy. It’s really similar to the B. hortonii I’ve seen except for the rather well-developed reticulum.

These fruitbodies are definitely more extreme, but a few other observations labeled B. hortonii show a kinda-sorta reticulum. observation 201089 and observation 348679 for example.

I think that feature has some potential for for pretty dramatic variation, especially for these “pseudo-Leccinum” things

It’d be great if you had a specimen.

Created: 2013-07-15 18:05:41 EDT (-0400)
Last modified: 2016-03-22 22:25:16 EDT (-0400)
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