Observation 178177: Pluteus saupei Justo & Minnis
When: 2014-09-13

Solitary fruit body found on hardwood in a mixed hardwood floodplain.

5cm, minutely hirsute at disc, striatulate, not hygrophanous, bruising blue where damaged

Deep, at first white becoming flesh colored, free from stipe, bruising blue where damaged

Fragile, whitish, bruising blue where damaged

7.42, 6.59
8.36, 6.95
7.88, 6.44
8.02, 6.82
8.07, 6.76
8.63, 6.35
8.69, 6.53
6.88, 5.84
7.79, 6.53
7.60, 7.10
8.36, 7.11
8.12, 6.53
7.92, 7.11
8.79, 6.40
7.28, 5.95
9.98, 7.79
8.41, 7.64
7.44, 7.04
8.35, 6.94
7.89, 6.08
8.85, 6.73
8.50, 6.34
8.62, 6.52
7.88, 6.14
7.40, 6.80
6.60, 6.44
8.52, 6.37
8.69, 6.57
7.35, 6.58
8.04, 7.00

Range: (9.98)6.60 X 5.95(7.79)
Q: 1.3-1.11
AVG:8.08 X 6.21
Q: 1.3

Exclusively two spored.

Versiform, ranging from mucronate, strangulated, cylindrical with a rostrate apex and digitate.

Narrowly utriform, apicies truncate to obtuse.

88.54, 20.54
102.20, 24.43
114.45, 35.38
94.52, 27.78
93.60, 26.07
98.05, 25.93
102.45, 31.47
101.81, 22.20
73.34, 18.94
82.50, 17.10

Range: (102.45)82.50 X 17.10(35.38)
Q: 4.8-2.9
AVG: 95.15 X 24.98
Q: 3.8


A trichoderm, two hyphae types, inflated type with irregular mucronate/rostrate terminal elements and afilamentous type with clamped septa. Both hyphae types perpendicular to the pileus, interweaving.


Horned pleurocystidia found nearest pileus
Filamentous pileipellis hyphae with clamped septa
Inflated pileipellis hyphae with irregular terminal cells
Inflated pileipellis hyphae with irregular terminal cells
Inflated pileipellis hyphae with irregular terminal cells

Proposed Names

28% (3)
Recognized by sight
2% (3)
Based on microscopic features: Thin walled pleurocystidia and mixed length terminal hyphae on a filamentous pileipellis
2% (3)
Recognized by sight: striate cap margin; bluing at stem base.
Based on microscopic features: spore size a match; cystidia w/out spines.
50% (1)
Recognized by sight

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
oh yeah, love that!
By: Debbie Viess (amanitarita)
2014-09-15 12:24:43 CDT (-0400)

it was only the bluing character that had me jump in on this ID. I am hardly a Pluteus expert, but with such a unique trait (bluing on both cap and stipe and apparently, gills, too), I figured that I actually had a prayer of finding a potential macro match, with a bit of searching.

I’ll leave that micro debate to you fellas with the in-hand material.

The lamellae
By: Rocky Houghtby
2014-09-15 12:03:02 CDT (-0400)

Bruise as well, Deb. It was interesting to see my sections turning blue as I cut. :)

well, that’s the beauty of running the DNA
By: Debbie Viess (amanitarita)
2014-09-15 11:56:08 CDT (-0400)

it confirms or denies our original “guesses,” and broadens our concept of just what sorts of variability are found within a species. Quite a bit, I’d imagine. But I can wait for those lab results!

Very cool find, and how nice that the original species description of saupei was also from Illinois, of a Pluteus that blues on both cap and stipe. That’s gotta be good for something! ;)

Thanks for offering to take this a bit further, Fredo.

By: Alfredo Justo (Fredo)
2014-09-15 11:53:02 CDT (-0400)

yes, the pileipellis does not look totally as a cutis in the photos but it does not look as a true trichoderm (like the ones in section Hispidoderma) either. I will take a closer look once I receive the material.


By: Rocky Houghtby
2014-09-15 11:42:29 CDT (-0400)

well hopefully you can get some useful sequences out of the material. I am willing to ignore the inconsistencies in pileus shape, gill spacing, spore size, basidia type, cheilocystidia type, pleurocystidia size and shape and absence of clamps in the hymenium because, as you have pointed out, there have been so few specimens collected. However, If P saupei truly has a cutis then I think we have a problem. The hyphae in the pilepellis of this observation are mostly perpendicular to the pileus. As I mentioned before, I am unsure how to describe this pilepellis. Perhaps the filamentous type hyphae may occur preclinally, but the inflated type hypahe with cystidioid apices are the ones that protrude most frequently. Thanks for the input, Fredo. Ill let you know when I mail the samples.


very likely P. saupei
By: Alfredo Justo (Fredo)
2014-09-15 09:01:31 CDT (-0400)

the shape of the cheilocystidia is very similar to what we found in the holotype and the other collection known of Pluteus saupei. All other characters also point to this species

if confirmed, this would be the third collection of Pluteus saupei ever made

so much still to discover right in our backyards…

Would you look at that!
By: Caleb Brown (Caleb Brown)
2014-09-15 00:24:35 CDT (-0400)

Looks at those horns!
I love it when im wrong, great additional micrographs!

By: Rocky Houghtby
2014-09-14 19:56:44 CDT (-0400)

Thank you all for the comments!

Hi Fredo, thanks for the guidance regarding the pleurocystidia. You are correct, they do indeed have very rudimentary horns, especially those situated nearest the pileus. Im not sure I would call any of these cells thick walled, but when you consider how large the cystidia are the line blurs. In addition to looking at the Pleuro again I have added photographs of the cheilocystidia, as you can see they are versiform, some digitate. Please also note that only two spored basidia have been observed.

As I’m sure you can imagine, this specimen was not very easy to section. I have provided new pictures of the pileipellis. There are two Hyphae types- large inflated hyphae with irregular terminal cells and much thinner filamentous hyphae with clamped septa. The two types of hyphae are arranged anticlinally to the pileus and frequently weave together, bunching up very tightly in some spots. I am not sure how to properly describe this surface.

I will happily send you some material.

no apology necessary.
By: Debbie Viess (amanitarita)
2014-09-14 19:34:12 CDT (-0400)

I am hardly a Pluteus expert, just thought that it might be a match. The bluing made it easy to zone in on some likely species.

We all learn here in MO!

Sorry Debbie, I stand corrected.
By: Caleb Brown (Caleb Brown)
2014-09-14 19:20:27 CDT (-0400)
cool find
By: Alfredo Justo (Fredo)
2014-09-14 17:05:35 CDT (-0400)

very cool find Rocky. I think this is in the salicinus group, and as suggested by Debbie you should compare it in detail with Pluteus saupei

The external aspect of the cap suggests a pileipellis as a cutis but in the microscopical photos it appears more trichodem-like, altough the general orientation or the individual elements are hard to see. Can you try checking again the pileipellis structure in a place a way from the center of pileus?. Check for the morphology of the terminal elements and the presence of clamp-connections.

There is some thickening of the walls in the pleurocystidia, especially on the widest cental part and at the apex. Several taxa in the salicinus group have very poorly developed metuloids (in comparison with other species in section Pluteus)

Check also for the shape and size of the cheilocystidia.

Pluteus saupei is only known from two herbarium collections so we have a very limited knowledge of the variation of its morphological characters. Even if your collection does not fit the description perfectly it could very well represent that species.

If you can send me a fragment of this collection for DNA analysis that would be great

It is likely another species.
By: Caleb Brown (Caleb Brown)
2014-09-14 14:49:26 CDT (-0400)

P. saupei is describes in sect. pluteus.
It is described as having metuloid pleurocystidia.

By: Jon (watchcat)
2014-09-14 12:13:39 CDT (-0400)
not a perfect fit with cyanopus, either.
By: Debbie Viess (amanitarita)
2014-09-14 11:28:49 CDT (-0400)

altho closer than salicinus!
Where is there a better NA Pluteus key, with more bluing sp? (found it! see below)

Nice documentation, Rocky.

Also check out the description of Pluteus saupei, which blues on both cap and stem, and with collections from Illinois!


Awesome OBS Rocky!
By: Caleb Brown (Caleb Brown)
2014-09-14 01:49:02 CDT (-0400)

Created: 2014-09-14 00:39:01 CDT (-0400)
Last modified: 2014-09-15 22:18:00 CDT (-0400)
Viewed: 687 times, last viewed: 2016-10-28 10:26:50 CDT (-0400)
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