Observation 202838: Pluteus sect. Pluteus

When: 2015-04-14

Collection location: Mormon Emigrant Trail, El Dorado Co., California, USA [Click for map]

Who: Ron Pastorino (Ronpast)

Specimen available

Single fruit-body growing on the ground/woody debris in old logged area.
Cap 7.1 cm across.
Odor rather strong, which I will call raphanoid.
Spore print pinkish.
Spores ~ 7.1-9.0(9.5) X 5.9-7.0(7.5) microns, broadly ellipsoid to ellipsoid.
Q(range) = 1.16-1.36 Q(avg)= 1.23 n=21
Cheilocystidia mostly clavate
Pleurocystidia abundant, 55-105 X 13-30 microns, thick walled near apex with horns.
Clamp connections on pileipellis.
Closest match seems to be P. brunneidiscus except the spores on these appear wider and a lower Q(avg).


Clamps on pileipellis
Clamps on pileipellis
Cheilocystidia with Congo red @ 1000X.
Cheilocystidia with Congo red @ 1000X.
Pleurocystidia with Congo red @ 1000×.
Pleurocystidia with Congo red @ 1000X.
Pleurocystidia with Congo red @ 1000X.
Spores in KOH
Spores in KOH

Proposed Names

29% (1)
Recognized by sight
61% (2)
Eye3 Eyes3
Recognized by sight
Used references: Phytotaxa 180(1) 2014 Justo et. al.

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Since the spore size appeared to be off ,
By: Ron Pastorino (Ronpast)
2015-04-17 17:11:41 CDT (-0400)

I retested.
Spores 6.9-9.0(9.9,10.2) X 5.8-7.0 microns.
Q(range) = 1.13-1.46
Q(avg) = 1.26
Results are close to first test; larger spores tended to have higher Q #’s
Added spore micro photos.

Fredo, In reading all the descriptions
By: Ron Pastorino (Ronpast)
2015-04-16 22:01:47 CDT (-0400)

in your Phytotaxa paper, I’m leaning a little toward P. parilis, the Yosemite collection. But the spores on this one still seem a little too round.
I’ll save it in case someone wants to look at it.

By: Alfredo Justo (Fredo)
2015-04-16 10:53:20 CDT (-0400)

Yes, if this was growing on conifer litter that would point towards the species in the pouzarianus group, and of those, the two most likely candidates given your location would be P. primus and P. parilis

The problem with P. brunneidiscus is that we still know very little about its ecology, it has been recorded on hardwood logs and on conifer litter, but many collections have been made on the litter layer without direct connection to wood or on very decayed wood but without knowing the nature of the wood (conifer or hardwood)

A close look at the cheilocystidia (morphology and size) and the pileipellis hyphae (are there clamps at all the septa?) can help you decide between the alternative id´s

Fredo, yes the litter was primarily conifers.
By: Ron Pastorino (Ronpast)
2015-04-16 00:00:10 CDT (-0400)

Would that give a slight nod to P. primus?

Hi Ron
By: Alfredo Justo (Fredo)
2015-04-15 22:53:45 CDT (-0400)

Was this on conifer wood/litter?

Pluteus brunneidiscus is a possibility, it has not been recorded from mountain areas in California, but there are records of it from mountain areas in other parts of the West

If conifers were abundant Pluteus primus is also a possibility. Length of the cheilocystidia (many over 70) and clamps in every septum of the pileipellis are typical for Pluteus primus

The relatively broad spores also fit well the collection of Pluteus parilis (not yet formally described) made in Yosemite National Park

Created: 2015-04-15 21:00:54 CDT (-0400)
Last modified: 2015-04-17 17:03:25 CDT (-0400)
Viewed: 142 times, last viewed: 2017-10-14 00:57:11 CDT (-0400)
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