Observation 81127: Suillus brunnescens A.H. Sm. & Thiers

When: 2011-10-28

Collection location: Yosemite National Park, California, USA [Click for map]

Who: Debbie Viess (amanitarita)

Specimen available

collected by David Rust.

Species Lists



Proposed Names

-43% (2)
Recognized by sight: purplish white veil that doesn’t leave a ring.
Used references: North American Boletes, Tom Bruns found it, too, this weekend.
-43% (4)
Based on chemical features: KOH turned context gray.
61% (2)
Eye3 Eyes3
Recognized by sight: If under sugar pine obligately. White cap becomes brown when exposed, with false veil at margin of pileus
Used references: Halling, R.E. 1976. The Boletaceae of the Sierra Nevada. M.A. thesis. San Francisco St. Univ. 115 p.

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
To amanitarita:
By: Roy Halling (royh)
2011-11-02 21:40:21 CDT (-0400)

Suillus is one of the most amazing genera of boletes. California is loaded with them and I would wager (based on idle conversation with HDT) it is because of the tremendous number of conifer species in the state. I found Suillus lakei in the foothills of the Sierra Nevada (near Greeley Hill) – Doug Fir right? Took me awhile, but there was one Doug Fir amidst huge amounts of ponderosa (fuscotomentosus) and lambertiana (yup, brunnescens won the award that day). Middle elevation Sierra Nevada - what a sweet habitat - so overlooked and undercollected.

Thanks Christian for that.
By: Roy Halling (royh)
2011-11-02 21:39:13 CDT (-0400)

T. Baroni wrote a paper in Mycologia in the late 70s on chem reax in boletes. To my knowledge, nothing as exhaustive has been duplicated.

I’d tend to agree with the last proposal
By: Christian (Christian Schwarz)
2011-11-02 18:15:49 CDT (-0400)

KOH reactions recorded in the literature are (in my book) subject to a certain filter of skepticism.

They may be based on a single collection, on specimens of varying age (old mushrooms sometimes react weirdly or not at all), or they may be based on part of a misidentified collection and then parroted in successive generations of field guides.

For a horribly frustrating example of this, ask Noah about distinguishing Boletus gertrudiae vs old Boletus separans sometime…

By: Debbie Viess (amanitarita)
2011-11-02 13:31:53 CDT (-0400)

that a “mere” Suillus could generate such controversy??! ;)

We did recognize that it was something different when we first collected it, but which Suillus sp. it actually was is best left to our talented Boletologists; take a bow, fellas.

So, in answer to my unanswered question, is the KOH rxn NOT valid? Cause I didn’t get a hint of pink or vinaceous, just gray.

Can KOH go bad over time and cause odd color rxns?? Or does the distinctive macro just trump chemical tests, which might be subject to unknown variables???

Inquiring minds…

I was thinking the same thing.
By: Tom Bruns (pogon)
2011-11-01 16:49:55 CDT (-0400)

I’d second Roy’s worry. They might be synonyms – in which case the correct name is brunnescens. Looks like a job for some type sequencing. But until that’s done, brunnescens seems like a reasonable fit, until we get other data (spore measurements).

In any case a really cool find.

By: Roy Halling (royh)
2011-11-01 16:38:51 CDT (-0400)

Could it be that brunnescens and borealis are the same thing? 5-needle pines – Yikes!

By: Roy Halling (royh)
2011-11-01 16:30:44 CDT (-0400)
We saw the same thing, I think; and ours was under sugar pine.
By: Tom Bruns (pogon)
2011-11-01 16:20:13 CDT (-0400)

It looks pretty similar to ours. I really don’t know either brunnescens or borealis, other than by name, but it keyed to borealis in Arora, and David Arora was on hand to confirm it. So it fits his concept, but I’ll dig into the literature a little and see if I can sort out the differences in Harry’s concepts.

The collection we have belongs to a student in the class, so I will wait for her to post it, but I might pinch in off the drier and look at the specimen more closely.

Returning to Debbie’s collection if you blow up her photo, it looks like there is at least one needle fascicle with 5 needles in the background. At that elevation its sugar pine.

Reading through the descriptions in “California Mushrooms” (i.e., Harry’s California Bolete book). It seems like borealis should have broader spores (3-5 w) vs. (2.8-3.2 brunnescens), assuming that is correct and holds we should be able to sort them out. Both are reported with Sugar Pine in the description, but strangely the key in the back of the book says borealis is not with sugar pine (apparently an error). The immature color of borealis is not clear, where the immature color of brunnescens is white.

conifers of Yosemite
By: BlueCanoe
2011-11-01 14:29:06 CDT (-0400)

If by “west entrance” you mean the Hodgdon Meadow area (as opposed to the much lower El Portal entrance), I’d say your two choices for pines would be P. lambertiana and P. ponderosa, which are easily distinguished by needle bundles (5 vs. 3, respectively), cones (huge and oblong vs. moderately-sized, round, and prickly), and bark (reddish vs. yellowish).


By: Roy Halling (royh)
2011-11-01 14:19:47 CDT (-0400)

HDT says KOH- context vinaceous lilac on the cuticle, slowly changing to greenish in places . REH says KOH – context pink, tubes pinkish cinnamon. EtOH – context yellow. H2SO4 – context yellow then vinaceous, tubes cinnamon. HCl – context yellow. NH4OH – context pink, tubes pinkish cinnamon.

Yep, photos in Bessette et al came from HDT who photographed it fresh the first time I showed it to him (either Tuolumne Co. or Mariposa Co.).

Still leaning toward S. brunnescens.

ruh roh…
By: Debbie Viess (amanitarita)
2011-11-01 13:36:19 CDT (-0400)

the gray staining with KOH still doesn’t fit either brunnescens or borealis.
Brunnescens is also covered (with a photo) in the Bessettes Bolete book.

I will have to double check the elevation at that point, but sugar pine occurs in the Park at 5,000’, and the slightly lower nearby Hodgdon Meadow campground is 4,900+. Still, that KOH result. :(

hot stuff!
By: Debbie Viess (amanitarita)
2011-11-01 12:58:17 CDT (-0400)

we struggled to find a match for this one. it would also explain the vinaceous staining at the base of the more mature specimens that we collected.

If it was under
By: Roy Halling (royh)
2011-11-01 12:21:51 CDT (-0400)

Pinus lambertiana (sugar pine), and seeing that it is white but becoming brown, with a false veil, I’d lay odds that it is Suillus brunnescens. It is in Thiers’ California Boletes, but he hadn’t seen specimens at the time the book was published.

uh oh, a tree question!
By: Debbie Viess (amanitarita)
2011-11-01 10:36:57 CDT (-0400)

sorry Christian, I am bad at tree ID.

Plus, as you will see by my name change, KOH (turning the context gray rather than vinaceous) last night proved this specimen to be the very similar but more commonly encountered Suillus luteus. Ah, sweet wishful thinking! ;)

We’ll have to wait for Tom’s group to post their photos of borealis (collected separately from us).

Neat one – what conifers were these with?
By: Christian (Christian Schwarz)
2011-10-31 22:12:16 CDT (-0400)

Created: 2011-10-31 16:29:48 CDT (-0400)
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