Observation 93719: Pluteus tomentosulus Peck

When: 2012-04-29

Collection location: Sauvie Island, Oregon, USA [Click for map]

Who: Sava Krstic (sava)

Specimen available

Single specimen collection. Found by Matt Sipes and brought (together with a piece of wood it was growing on) to the ID session at the end of our field trip.

Smell mild. Spores 6-7 × 5-6 microns. No clamps in the pileipellis hyphae.

Proposed Names

-51% (2)
Used references: Funga Nordica
85% (4)
Eye3 Eyes3
Recognized by sight: Pilius too pubescent for P. pellitus
Based on microscopic features: Cheilocystidia: tomentosulus = fusoid ventricose with obtuse to rounded apices; pellitus = clavate to sphaeropedunculate
Spores too short for pellitus. tomentosulus (5.5-7 × 5-6); pellitus (7.0-8.5 × 4.5-5.5)

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Sava Krstic (sava)
2014-06-26 10:59:44 CDT (-0500)

Thank you for your work.

Pluteus tomentosulus
By: Alfredo Justo (Fredo)
2014-06-26 09:12:58 CDT (-0500)

Hi Sava,

The nrITS sequence from your collection is identical with this collection of P. tomentosulus from Eastern North America


Thanks again for documenting and sending the collection!

specimens arrived
By: Alfredo Justo (Fredo)
2012-05-08 12:10:24 CDT (-0500)

Sava, your collections arrived today. I’ll hopefully get to check them in detail soon


thanks sava
By: Alfredo Justo (Fredo)
2012-05-03 10:23:33 CDT (-0500)
By: Sava Krstic (sava)
2012-05-03 00:29:37 CDT (-0500)

Drew, thanks for quickly correcting my ID and listing differences precisely. In fact, I’ve found P. tomentosulus once before(observation 93766, just posted), but somehow neglected to consult MatchMaker when making the first rushed ID.

Else and Fredo, thanks for spending time to educate us in Pluteus. Greatly appreciated. Fredo, I’ll mail you the two requested collections, and as a bonus will include observation 93766. Please note that the two P. tomentosulus collections are from different habitats. This one is found near water, in a cottonwood forest; the other one is from a mountain (Doug fir, true fir, hemlock).

Tatiana, I saw today your Pluteus postings on flickr. Thanks for sharing those beautiful photos.

By: Drew Parker (mycotrope)
2012-05-02 15:24:29 CDT (-0500)

I’ve found this species numerous times in northeast Washington state, though not commonly. Tomentosulus has also been reported from British Columbia and Alberta. I strongly believe it is tomentosulus, so if you examine this collection Fredo, please post your findings.

By: Alfredo Justo (Fredo)
2012-05-02 14:14:58 CDT (-0500)

As Else has pointed out microscopy is always a must to ID Pluteus so is nice to see microscopy photos in the observations.

This is very likely in section Hispidoderma and Pluteus tomentosulus is a reasonable guess. P. tomentosulus was originally described from Upstate New York and it is depicted in some Mushroom guides for the Northeast but I have not found it myself yet.

Some Pluteus species are not that particular about geography so this west coast specimen could very well be tomentosulus.

Sava, if you could send the specimen over I would definitely take a look at it. The same goes Pluteus “plautus” collection (http://mushroomobserver.org/93671?q=DbQl)


Pluteus and clamp connections
By: else
2012-05-02 13:15:21 CDT (-0500)

One more thing to complete the simple and quick guide to the genus Pluteus:

Clamp connections – only present, but not in all species, in the first group, section Pluteus, the one with the cutis and the thick-walled horned pleurocystidia.

Pluteus groups – pileipellis and cystidia
By: else
2012-05-02 11:49:34 CDT (-0500)

Some basic comments on Pluteus classification.
There are three main groups in the genus:
the group with a cutis as pileipellis (long radiating hairs that hardly stick up – think straight hair) AND thick-walled pleurocystidia that are horned at the top: species that belong to this group are P. cervinus, P. pellitus, P. nothopellitus, P. atromarginatus, P. petasatus, P. pouzarianus etc.
the group with a celluloderm (up right tightly packed club-shaped, balloon-shaped cells or this kind plus longer cells), thin-walled cystidia: P. phlebophorus, P. aurantiorugosus, P. romellii etc
third group, upright long cells, thin-walled cystidia, often also caulocystidia: P. leoninus, P. semibulbosus, P. plautus etc.
In all groups white non-coloured of normally coloured specimens occur, making identification based on morphology alone tricky.

This species here: no thick-walled horned cystidia, so P. pellitus is out of the question.
The pileipellis is not a celluloderm, so it should fall in group 3.

Alfredo Justo is really the Pluteus specialist – he might be interested in the specimen.

Cool white Pluteus!
By: Tatiana Bulyonkova (ressaure)
2012-05-02 07:22:59 CDT (-0500)

Interesting blunt pleurocystidia, too.
Regarding the P. pellitus version: it is supposed to have at least some clamps in many tissues. But then there’s also the clamp-less P. nothopellitus (still a bit different).
I guess mycotrope has a point :) As for me, I’ve only seen a couple of photos of P. tomentosulus to be able so say anything meaningful about it :D

Created: 2012-05-01 23:13:42 CDT (-0500)
Last modified: 2014-06-26 12:02:58 CDT (-0500)
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