Observation 217610: Leccinum A.H. Sm. & Thiers sect. Leccinum
When: 2015-09-26
(42.9596° -77.682° )

Notes: Three youngish basidicarps growing next to each other in a stand of young bigtooth aspen (Populus grandidentata) intermixed with a bit of black oak [tree ID by R. J. Cook of RAMA].
> PILEUS: dark orange-brown (the flash in pix makes it more orange than brown) with a flap of sterile tissue [this feature places the specimens in Leccinum sect. Leccinum sensu Smith & Thiers]
> CAP SURFACE: noticeably fibrillose (see pix)
> PORE SURFACE: whitish, staining brown upon injury
>STIPE: whitish with a dense cover of appressed blackish scabers
> EXPOSED CONTEXT: staining grayish-violet, the color intensifying over time; NO preliminary reddish-cinnamon stage (typical of stirps Aurantiacum) was observed
> FeSO4 on context = greenish-blue, resolving pale blue

Molecular Data Discussion:
>A clean 1440 bp nrLSU sequence was obtained for this material
>A GenBank BLAST search of the full-length sequence did not produce a close match. The best hit in terms of identity match was a 1018 bp sequence from the Leccinum aurantiacum voucher HN1573, accession #AY612810 (99% identity with 2 gaps; 1014/1019 bp overlay, only 70% coverage).
>A GenBank BLAST search of a shorter fragment of my sequence (the first 971 bp) yielded several high-score hits with several red/orange capped leccinum taxa. The aforementioned L. aurantiacum voucher HN1573 was the top score hit (score = 1668 pts; 914/919 bp overlay, 94% coverage; 99% identity with 2 gaps).
> On the other hand, the two top highest identity hits belonged to the L. vulpinum voucher KPM-NC-001783, accession #JN378516 (score = 1607 pts; 872/873 bp overlay, 89% coverage; 99+% identity with no gaps), closely followed by the L. piceinum strain Lp1, accession #DQ534614 (score = 1602 pts; 869/870 bp overlay, 89% coverage; 99+% identity with no gaps). The latter two species are of European origin and occur under conifers, while L. aurantiacum is also a European taxon that is found under a variety of broadleaf trees. None have been conclusively proven to occur in North America.

The full LSU sequence of this material didn’t match closely any leccinum sequences posted in GenBank because of a dearth of sequences of comparable length. A search of a sequence fragment led to many non-specific hits with a wide variety of scaber-stalk taxa with red or orange caps. Clearly the nrLSU gene doesn’t provide a sufficient resolution capacity below a certain sequence length and might not be able to provide it for full-length sequences either.


Cap texture is fibrillose
Taken ~1 minute following dissection
Taken ~7 minutes following dissection

Proposed Names

28% (1)
Used references: The Boletes of Michigan by Smith & Thiers

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
DNA discussion posted
By: I. G. Safonov (IGSafonov)
2016-01-16 23:18:52 PST (-0800)

Created: 2015-10-03 14:33:35 PDT (-0700)
Last modified: 2016-03-19 17:09:59 PDT (-0700)
Viewed: 50 times, last viewed: 2017-02-19 05:30:34 PST (-0800)
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