> A single large and robust basidiome growing on the edge of a trail in mixed pitch pine & oak woods in the Speedwell section of FPP.
> I’ve posted this species several times on MO — all collections are from the NJ Pine Barrens.
> This is the earliest fruiting I have ever observed.
> The cap of this young specimen was almost 5" in diameter; the stipe was ~7" long and 1.5" wide.

DNA Sequencing Discussion (final update 6-Nov-17):
> A clean and contiguous 1368 bps nrLSU sequence has been obtained for this material. The first 70+ bps from the beginning of the LSU region are missing.
There is a single ambiguous character, a “Y”, corresponding to either of two the pyrimidine bases, cytosine “C” or thymine “T”.
> A GenBank BLAST search of the full-length sequence returned no meaningful hits.
> A GenBank BLAST search of a bps sequence fragment (the first 886 bases) returned a nearly perfect match (867/868 bps overlay, 99.9% identity match) to Boletus oliveisporus voucher DPL6823 [accession #KF030254]. The next several hits with identities in the 97-98% range are members of Neoboletus and Rubroboletus.
> Morphologically and genetically, B. oliveisporus is likely a member of the unresolved “Pulveroboletus Group”, a dustbin containing many generic clades that haven’t been assigned to any of the 7 existing subfamilies within the Boletaceae.1 Its gestalt morphology suggests it belongs in a yet to be named generic clade.
Case closed.
1 “Molecular Phylogenetic Analyses Redefine Seven Major Clades and Reveal 22 New Generic Clades in the Fungal Family Boletaceae”, Fungal Diversity 2014, 69(1), pp. 93-115.

Species Lists


Proposed Names

90% (2)
Recognized by sight
Based on chemical features: a 99.9% identity match to the nrLSU sequence of a B. oliveisporus voucher in GenBank

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= Observer’s choice
= Current consensus


Add Comment
DNA discussion posted
By: I. G. Safonov (IGSafonov)
2016-01-27 22:41:37 MST (-0700)

LSU sequencing confirms that this is indeed B. oliveisporus.

By: I. G. Safonov (IGSafonov)
2015-07-04 13:55:51 MDT (-0600)

According to Wu et al. (2014), Cyanoboletus (clade 48) and Lanmaoa (clade 49) are very closely related.

Eva, I have collected pulverulentus…
By: Dave W (Dave W)
2015-07-04 13:35:38 MDT (-0600)

that is clean and dry. obs 170957

B. pulverulentus
By: Eva Skific (Evica)
2015-07-04 12:53:45 MDT (-0600)
is slimy and dirty this one look clean
I should be able to get you…
By: Dave W (Dave W)
2015-07-04 12:00:01 MDT (-0600)

collections of pulverulentus.

Yes, Dave,
By: I. G. Safonov (IGSafonov)
2015-07-04 11:49:43 MDT (-0600)

all components of this mushroom bruise deep blue, including the cap cuticle; the pores are exceptionally sensitive — you can drag a hair across the bright yellow surface and it will blue. The flesh immediately stains blue first and then transitions into brown after a few minutes. Kuo says C. pulverulentus is similar, but stains green-blue, and is much smaller in size.
It’s on my wish list for sequencing.

Igor, does this…
By: Dave W (Dave W)
2015-07-04 11:23:52 MDT (-0600)

bruise like crazy? Lots of black, and other shades, all parts? Wondering how close it is to pulverulentus.

Common in the Barrens
By: I. G. Safonov (IGSafonov)
2015-07-03 20:01:18 MDT (-0600)

This mushroom is an amazing blue stainer, especially on the pore surface. According to a Texas field guide, it’s edible. I haven’t tried it, thought it’s tempting. The flesh is dense and a single large mushroom can easily make a meal. :-)

Nice Find
By: John Plischke (John Plischke)
2015-07-03 19:56:26 MDT (-0600)

I hope to see this one someday