Observation 163299: Pluteus plautus group

Growing on old log in mixed woods.
Cap 3.4 cm across, central portion with brown granules and spreading in random pattern.
Spores ~ 6.1-7.1(7.8) X 5.0-6.0 microns, subglobose to broadly ellipsoid.
Cheilocystidia clavate to utriform, ~ 30-55 X 12-26 microns.

ID is tenuous as the the only Cystidia values I could find were on Mushroom Expert and they did not agree.
Hopefully, one of our fine Pluteus experts will comment.


Proposed Names

-11% (2)
Recognized by sight
-76% (1)
Recognized by sight
76% (1)
Recognized by sight

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Add Comment
Thank you Gentlemen!
By: Ron Pastorino (Ronpast)
2014-06-26 17:05:39 CDT (-0400)
By: Rocky Houghtby
2014-06-26 10:12:04 CDT (-0400)

Yet another splendid obs.

in the Pluteus plautus group
By: Alfredo Justo (Fredo)
2014-06-26 10:04:56 CDT (-0400)

Hi Ron,

I got some sequence data for this and it is not P. umbrosus or P. granularis.

This collection belongs in the Pluteus plautus species complex. I have collections of this species from the Adirondacks and Spain, and there are also a couple of Californian collections in GenBank that are the same thing.

I do not have a name for this yet. We might be able to use one of the available European or North American names in this group for this species, but I will have to look more closely into that.

Thanks again for documenting and sending the collection!

Thanks Fredo.
By: Ron Pastorino (Ronpast)
2014-04-25 16:29:05 CDT (-0400)
could be Pluteus umbrosus
By: Alfredo Justo (Fredo)
2014-04-25 13:36:34 CDT (-0400)

Hi Ron,

I have scoped this collection and I do not think this is P. granularis. The gills edges appear colored under the lens and the morphology of both pleurocystidia and cheilocystidia is quite different from what I have observed in the collections of Pluteus granularis that I have studied from Eastern North America.

I think this could be Pluteus umbrosus, originally described from Europe but perhaps present in North America (at least in the West). I do have a collection of P. umbrosus from the NAMA foray in California that comes very close, morphologically and molecularly, to a collection of P. umbrosus from Spain. I will try to obtain molecular data for your collection and see if it goes in the same place in the phylogenies as the other P. umbrosus sequences.

No problem Fredo,
By: Ron Pastorino (Ronpast)
2014-04-16 19:37:07 CDT (-0400)

I’ll send it to you in a few days.

By: Alfredo Justo (Fredo)
2014-04-16 15:41:59 CDT (-0400)


If it is not too much to ask, can you send this specimen over?; I am curious to check if it really is granularis

Ron, I just thought maybe…
By: Dave W (Dave W)
2014-04-16 12:50:34 CDT (-0400)

this is a way to explain the change in paleness as a function of the mushroom being hygrophanous, that is, as a function of moisture distribution within the mushroom.

The canopy was fairly thick but I don’t recall
By: Ron Pastorino (Ronpast)
2014-04-16 01:32:21 CDT (-0400)

how much in the open this specimen was. It was off the ground fairly high so it’s possible that it could have gotten appreciable sun at some point in the day.

Was this collected in a sunlit area?
By: Dave W (Dave W)
2014-04-15 22:04:26 CDT (-0400)

Maybe after it was taken away from direct sunlight the moisture level reverted toward equilibrium.

Maybe, but the pale colors weren’t
By: Ron Pastorino (Ronpast)
2014-04-15 20:40:34 CDT (-0400)

really centered and appeared to be more on one side. And as I recall when I got them home, the paleness was less obvious.

Looks hygrophanous to me…
By: Christian (Christian Schwarz)
2014-04-15 19:32:42 CDT (-0400)

The center of the cap is paler as moisture is lost?

The specimen was a little weathered and the conditions were drying out.
By: Ron Pastorino (Ronpast)
2014-04-15 19:31:22 CDT (-0400)

It didn’t appear to me to be actually hygrophanous(?).
Thanks for the comments Fredo.

was the cap hygrophanous?
By: Alfredo Justo (Fredo)
2014-04-15 14:41:49 CDT (-0400)

in one the photos the cap seems to be hygrophanous, that is not something I usually observe on P. granularis

In the specimens of P. granularis that I see here in the East the margin of the cap is usually less markedly striate and the stipe is much more markedly covered in small brown dots or granules.

This could very well be an old/weathered specimen of P. granularis; another possibility is something in the species complex around P. plautus. This group still needs a lot of work

For sure this belongs on section Hispidoderma

Created: 2014-04-12 22:33:39 CDT (-0400)
Last modified: 2014-06-26 10:00:08 CDT (-0400)
Viewed: 148 times, last viewed: 2019-07-12 08:07:38 CDT (-0400)
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