Collectors: Sally Visher, Joseph D. Cohen
Substrate: Soil
Habitat: below undergrowth in relatively open area in coastal Picea sitchensis (Sitka Spruce) forest.
Nearest large tree: Picea sitchensis (Sitka Spruce). (No other conifer species anywhere near collection.)
Chemical: Cap cuticle may stain dark red in KOH; it’s hard to tell because of the age and water-logged state of this mushroom. Cap flesh negative in KOH.
Spores: Brown

Piximètre 5.9 R 1530 : le 20/06/2017 à 16:55:06.1172147
(12.4) 12.5 – 14.5 (15.8) × (4.9) 5.8 – 6.7 (6.8) µm
Q = 2 – 2.3 (2.7) ; N = 10
Me = 13.6 × 6.2 µm ; Qe = 2.2

Other: The blue staining seen in some photos appears to originate in the cap flesh around its edges. The final 3 macro photos (with white background) were taken ~2.5 hours after collecting this mushroom.


Undergrowth at collection site
MO2792330 (1).jpg

Proposed Names

31% (3)
Recognized by sight: Looks somewhat similar to the eastern Tylopilus sordidus, especially in the color of the pores and the staining (blue to dark red-brown). Sordidus is likely to wind up in Porphyrellus
31% (2)
Used references: Gibson, Matchmaker: Mushrooms of the Pacific Northwest, Version 2.2.1 (2015) (application, latest version downloadable at

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

= Observer’s choice
= Current consensus


Add Comment
Thanks for the update, Joseph
By: I. G. Safonov (IGSafonov)
2017-06-26 16:29:34 CDT (-0400)

Actually I thought this specimen was too lightly colored for the typical P. porphyrosporus. Perhaps it’s the metering and color balance of your pix that give this impression.

Feedback from locals
By: Joseph D. Cohen (Joe Cohen)
2017-06-26 16:24:59 CDT (-0400)


The gist of the feedback is:

1. Don’t assign too much significance to small differences in spore sizes, either in the cited literature, or between my measurements and the cited measurements.
2. This observation is darker than typical P. porphyrosporus, but — of course — this one is a very old specimen.
3. There’s a reasonable possibility that this is a species complex. One person who reviewed the six photos of P. porphyrosporus in MatchMaker thought there likely was more than one species shown.

So I now think that Porphyrellus is as good an ID for this Observation as P. porphyrosporus, and am revising my vote accordingly. (Lowering my Confidence for P. porphyrosporus to “Could be”.)

Thanks for your suggestions and thoughtful questions.

- Joe

Will ask others
By: Joseph D. Cohen (Joe Cohen)
2017-06-20 23:52:39 CDT (-0400)

I will see if I can someone to look at it.

Sources (secondary, non-academic) list slightly different ranges for spores sizes:
“spores 12-18 × 6-7.5 microns, elliptic, smooth, pale brown” MatchMaker
“spores 14-18 × 6-8 um” Scates, Gibson & Bishop, Trial field key to the BOLETES in the Pacific Northwest (rev. 2011),

Thanks, Joseph
By: I. G. Safonov (IGSafonov)
2017-06-20 23:33:48 CDT (-0400)

Well, I guess the spore measurements neither support nor eliminate P. porphyrosporus from consideration, but the spores are shorter and thinner than what’s reported in the literature for this species. Can any of the bolete experts from your area weigh in on this obsie?

Updated description
By: Joseph D. Cohen (Joe Cohen)
2017-06-20 20:24:05 CDT (-0400)

Added chemical, spores.

Hello, Joseph
By: I. G. Safonov (IGSafonov)
2017-06-20 12:08:47 CDT (-0400)

Thank you for all the info. Having never been in the West, I don’t have first-hand knowledge of the boletes from that part of the country. However, I am familiar with P. porphyrosoporus, too, as I’ve encountered it myself a couple of years back in NY, _obs 215762, and even sequenced it.
I am not entirely convinced your bolete is porphyrosporus based on what I see in your pix, unless this somber-looking species changes the colors toward a lighter shade in age, but I thought it might at least be Porphyrellus after noticing the uncanny semblance of its hymenophore & staining to that of T. sordidus. Yes, the mushroom is very old, so its appearances can be misleading.
Surely, you are the one who found and examined the mushroom, and you are also familiar with the mycota of your area. Having said this, your proposal has more weight, so porphyrosporus should fit the bill for this post-mature collection at this point in time. Let me know if you find more after scoping it.

P. porphyrosporus
By: Joseph D. Cohen (Joe Cohen)
2017-06-20 08:18:21 CDT (-0400)

Thank you for suggesting, and reminding me about, Porphyrellus.

P. porphyrosporus is the only Porphyrellus species listed in the excellent local (PNW) key, Gibson, Matchmaker: Mushrooms of the Pacific Northwest, Version 2.2.1 (2015) (application, latest version downloadable at I’ve seen other people’s collections, but not found it myself in the field. One or two of these usually turn up at the display table at the OMS Fall foray, only 15km away from the point of collection. See Observation 220487, Observation 150268, Observation 118795.

This single, old, very wet, basidiocarp has many of the characters listed there (but is also missing a number of them). I couldn’t get a spore print, I’m away from home so could not scope it. I will try taking a piece of it home to see if I have better luck there.

Created: 2017-06-19 20:15:32 CDT (-0400)
Last modified: 2017-06-26 16:25:14 CDT (-0400)
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