Observation 149452: Boletus fibrillosus Thiers

Found with Lithocarpus densiflorus.

Proposed Names

12% (4)
Used references: Thiers, H. D. 1975. California Mushrooms: A Field Guide to the Boletes. Hafner Press, New York, NY. 261p.
Francisco J. Camacho & Tom Bruns. (no date in pdf) The molecular systematics of the Western U.S. edible ectomycorrhizal mushrooms in the Boletus edulis complex, Boletus section Edules.

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
time to step away from the computer…
By: Debbie Viess (amanitarita)
2013-11-11 15:19:31 CST (-0500)

locale and host were being compared to that for mottiae vs regineus.

yup, there’s a lot of variability out there, even w/in species!

still, I don’t think that we can safely put a name to this photo, with the info at hand.

cap was “weathered” by what? certainly not rain.

By: Christian (Christian Schwarz)
2013-11-11 15:05:05 CST (-0500)

First of all hymenium color and location are uninformative with regards to B. fibrillosus or B. regineus. Second, we don’t know the MR host, only the trees around (I’m guessing it wasn’t pure tanoak).

The stipe color is within range of lighter B. fibrillosus:
observation 33961
observation 30085
observation 88143
The cap texture is just aged/weathered – commonly looks like this in B. fibrillosus. See observations:
observation 59538
observation 80820

By: Debbie Viess (amanitarita)
2013-11-11 14:50:34 CST (-0500)

stipe looks too pale, cap too smooth.

gosh, a mushroom photo ID that isn’t fitting neatly?

say it ain’t so. ;)

even tho it’s not a perfect fit either, I’m gonna propose regineus.
Reticulations fit, hymenium color fits, MR host and true coastal location fits, dark cap color kinda sorta fits.

that cap color is pretty wack, though.

European mottiae
By: Christian (Christian Schwarz)
2013-11-11 14:43:55 CST (-0500)

I agree with Debbie that the European and CA taxa are almost certainly not the same. It’s pretty clear that all the edulis-clade taxa look superficially fairly similar, with lots of potential for intergradation, esp. in aged or weather-affected specimens.

Another thing I’d like to bring up is that while Dr. Thiers may have been careful and did as much as he could with the tools and knowledge available, his species concepts can still be wrong… It was a much harder time in which to do taxonomy – which necessarily involves comparing the appearances of mushrooms directly – the lack of convenient and reliable photographic equipment and avenues for sharing – oof, I can only imagine…

thanks Darv.
By: Debbie Viess (amanitarita)
2013-11-11 14:06:04 CST (-0500)

Nor sure if this clarifies or confuses the issue, though! ;)

I doubt that the European and West Coast sp. are a DNA match, although there may well be something that is a macromorph match, kinda.

I would call the entire issue unresolved.

More info
By: Darvin DeShazer (darv)
2013-11-11 13:59:47 CST (-0500)

Boletus mottiae is also described in this publication and Klofac states that Dr. Thiers verified several collections from Europe and sites them. Also noted by Thiers is the association with Oaks, not Pines as he stated in the original publication: California Mushrooms.

KLOFAC, WOLFGANG . 2010. The genus Aureoboletus, a world-wide survey. A contribution to a monographic treatment. Österr. Z. Pilzk (19): 133-174.

SP is directly on the coast.
By: Debbie Viess (amanitarita)
2013-11-11 13:35:14 CST (-0500)

coastal mountains are inland, just not as far inland as the Sierra.

The authors of the UCB article make the exact same distinction.

Index Fungorum lists mottiae as mottiae. no other names, before or after. Regineus also has no mottiae synonym.

Yeah, no kidding, the newly named regineus was formerly our CA version (mistaken) of aereus, neither of which are mottiae, as it has been described.

Some folks might not be up on new names, so I threw them both in.

Why is that confusing to you?

All we have are the original descriptions to go by. This mushroom doesn’t match. One would expect MORE reticulations/wrinkling under dry conditions, wouldn’t you?

When I read “finely reticulate over entire surface,” I take the description at its word. Perhaps “majority of stipe” would have been better? But the original is all we have.

At any rate, I trust the DNA work of those who frequently do it.

Microfiche details are not clear, and the photo of mottiae in the Bessette book looks like a fibrillosus to me!

I do agree that our whole concept of mottiae could use a bit of a fine tuning.

But how curious that something different did pop out of the porcini tree at the Bruns lab.

I would like that porcini tree to get rerun with vouchered original material of mottiae as well as confirmed material of regineus. Despite both having a dark cap…there doesn’t seem to be a lot of similarity between those mushrooms as described and as I have experienced regineus…with apricot apical reticulation and a frosted cap when young.

And the well respected, taxonomically careful Thiers described mottiae and aereus (now regineus, for those with short atention spans) as separate species in his “California Mushrooms: A Field Guide to the Boletes.”

By: Christian (Christian Schwarz)
2013-11-11 12:35:34 CST (-0500)

The following statement on:
“mottiae… is not a former name for regineus. or our former CA aereus, for that matter.”
is redundant at least, or confusing. The ‘former CA aereus’ IS B. regineus.

This is also confusing:
“No coastal collections of mottiae have been reported up to this point from along the coast, just coastal mountains.”

So, if it’s been recorded in the coastal mountains, that would make it… known from the coast, right?

And for what it’s worth – the reticulations on this fruitbody go about as far down as it is possible for reticulations on a bolete to go. Functionall, I would call this “reticulate to stipe base”.

For those not familiar with the issues, B. mottiae is (theoretically) a species of eduloid bolete with an uncertain morphological concept – the strongly wrinkled/reticulate cap and extensively reticulate stipe are often mentioned.

However, it’s common for variation in both of these characters to be environmentally-induced.

As for ecology, the association with drier habitats and pine or Fagaceae hardwoods doesn’t even come close to convincingly separating it from coastal B. regineus.

As far as DNA goes, Bruns and Camacho apparently found a difference, but as you can see from comments below, there is some question about the validity of the results obtained so far. I have no real opinion on this other than that I agree with Darvin – there’s no reason to doubt the DNA.

In summary, I have no real strong opinion on the true identity of B. mottiae, but consider it possibly synonymous with B. regineus.

I think the mushroom in this observation is B. fibrillosus

reticulations certainly are not restricted to the apex…
By: Debbie Viess (amanitarita)
2013-11-11 11:57:24 CST (-0500)

but they also seem to stop before reaching the mushroom base.

the cap is NOT wrinkled and reticulate.

mottiae may have been misidentified by collectors as regineus, but is not a former name for regineus. or our former CA aereus, for that matter.

here’s the paper by Comacho and Bruns. Boletus mottiae is known from drier habitats. Here’s the quote:

“Boletus mottiae occurs in drier habitats but it fruits later in the Fall when there is plenty of rain and more humidity to avoid dessication.”

I would say that those conditions are not currently being met at SP, a normally wetter habitat that is currently pretty dry. No coastal collections of mottiae have been reported up to this point from along the coast, just coastal mountains.

still not convinced.

Reticulations on stipe
By: Darvin DeShazer (darv)
2013-11-11 01:43:06 CST (-0500)

The reticulations do go down all the way to the base and can be seen in the last photo. Lithocarpus densiflorus is a known tree associate.

Yes, but…
By: Darvin DeShazer (darv)
2013-11-11 01:39:47 CST (-0500)

I’m aware of that DNA research and I’m not sure its accurate. I spent four days with Dr. Camacho in the Sierras. I have no proof that the DNA is flawed, just a suspicion. Dr. Thiers was very solid, so I listed this to keep a record. Below is from Camacho & Bruns.

Boletus mottiae Thiers
Usually misidentified as B. aereus Bulliard: Fr., which is a European species.
Type locality: Grass Valley, Nevada Co. California
Habitat: In oak, madrone, and mixed woodlands in the foot hills of the Sierra Nevada, Cascades and throughout the coastal mountains. Host tree (potential): Quercus species, Pinus species, Pseudotsuga menziesii, Arbutus menziesii, Chrysolepis chrysophylla, Lithocarpus densiflorus
Distribution: Known from the coastal mountains of California from San Mateo Co. north to the coastal mountains of Oregon to Lane Co. Also occurring on the western foothills of the Sierra Nevada and North to the Oregon Cascades, Lane Co. Possibly throughout the Klamath Mountains and probably up to Washington and British Columbia, Canada.
Phenology: Late fall, October through December.

For what’s it worth;
By: Noah Siegel (Noah)
2013-11-10 23:52:11 CST (-0500)

B. mottiae is an older name for Boletus regineus

tempting to call it mottiae…
By: Debbie Viess (amanitarita)
2013-11-10 11:59:39 CST (-0500)

it certainly appears to be a very atypical “edulis.” Certainly in the porcini group. But which porcini?

From the Thiers description: I don’t see a wrinkled and reticulate cap, with the most prominant reticulations in the cap center. The stipe reticulations do not go down the entire stipe, but seem to stop towards the base.

The tan oak habitat and coastal location also vary from the original description of mottiae under pine in the mountains.

Did you send it to Tom? Might be worth a DNA run.

Created: 2013-10-21 01:08:33 CDT (-0400)
Last modified: 2016-06-22 15:04:06 CDT (-0400)
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