Observation 34384: Pluteus Fr.

When: 2010-02-12

Collection location: Los Trancos Preserve, Palo Alto, California, USA [Click for map]

Who: Douglas Smith (douglas)

Specimen available

Found under CA bay, big leaf maple.

This one is a little funny, mory grey than brown in the cap, and the gills are marginate, but only lightly grey.

Adding some micro details.

The first micro-shot is of the cap surface in radial section at 400x in KOH. Here the cap surface is a cutis, of slightly inflated pigmented elements. Looking around some of the elements point upward, but not many, and in all cases they are long hyphae, not globose elements.

The second micro-shot is of gill edge at 400x in KOH. Here the cheilocystidia can be seen, there are several different kinds here, some lageniform, some cylindrical, some clavate. And some are the womping big suckers, like large inflated balloons with a roughened surface. The edge cystidia are all slightly pigmented and smoky. Also obs. were plenty of pleurocystidia, which were mostly lageniform and thin walled, and hyaline. There were some, widely spaced, pleurocystidia that were largely inflated and smoky pigmented.

The third micro-shot is also of the gill edge at 400x in KOH, showing more of the different types of cystidia.

The forth micro-shot is of spores from the gill at 1000x in KOH. The spores are thick-walled, ellipsoid, smooth without a germ pore. The average size of the spores was measured as length – 7.34 +/- 0.47 (err 0.13) um, width – 5.60 +/- 0.39 um (err: 0.11) – q : 1.31 +/- 0.06, on 16 spores.

I knew this was an interesting one, and I wanted to use some of the ref. that Else mentioned recently on the BAMS e-mail list, and give it a try. These are pretty cool under the scope with the smoky cystidia. With the thin walled pleurocystidia, I got that this is in the section Hispidoderma of the genus Pluteus. But then I didn’t get anywhere else. It seems that the species in this section are not that well studied at all, for some strange reason…

So, I’ve got all this info on this guy, and then I’m not going to get anywhere else with it, it seems…

Species Lists


Proposed Names

57% (1)
Recognized by sight
28% (1)
Recognized by sight: are the gill edges darker?

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

= Observer’s choice
= Current consensus


Add Comment
Oh, yeah-
By: Douglas Smith (douglas)
2010-03-14 18:02:29 CDT (-0400)

Yeah, big time, this is not P. atromarginatus. I knew that right away. Even macro-scopically, the cap isn’t brown enough, and the gill edges aren’t dark enough. But yeah, it needs to have those hooked pleurocyst. like with P. cervinus. No, this is something different, from a different section of the genus.

Not atromarginatus
By: Irene Andersson (irenea)
2010-03-14 16:41:02 CDT (-0400)

it’s a species with hooked apex on the pleurocystidia, a large and very dark species that mostly grows on conifers.
I can’t find anything that matches this in my keys either :-(

Created: 2010-02-28 09:49:20 CST (-0500)
Last modified: 2010-02-28 09:49:20 CST (-0500)
Viewed: 89 times, last viewed: 2019-02-02 04:40:12 CST (-0500)
Show Log