Observation 65053: Polyporus P. Micheli ex Adans.

When: 2011-04-02

Collection location: Sauvie Island, Oregon, USA [Click for map]

Who: Sava Krstic (sava)

No specimen available

Found by Myxomop & Caba.

Cap 47 mm, growing on dead cottonwood branch.

Proposed Names

30% (2)
Eye3 Eyes3
Recognized by sight
-27% (1)
Recognized by sight: or something close – I haven’t seen this kind of zonate caps on them..
27% (1)
Recognized by sight: ?
-28% (1)
Used references: this site calls this mushroom: (images below) P. cf. vinosus. Judging by the description here: http://books.google.com/..., I don’t believe this to be the correct name, but the two pictures match up rather well.

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

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
By: Richard Kneal (bloodworm)
2013-02-06 00:47:01 -05 (-0500)

i also just realized this was growing on wood.

Ignore brown spores
By: Sava Krstic (sava)
2013-02-06 00:33:53 -05 (-0500)

Richard, those spores are brown, but as Irene pointed out, they belong to something else. Please pardon the inexperienced microscopist.

correct me if i am wrong…
By: Richard Kneal (bloodworm)
2013-02-06 00:21:08 -05 (-0500)

but the spores look brown…
wouldn’t that rule out all suggestions?

By: Irene Andersson (irenea)
2013-02-05 16:39:49 -05 (-0500)

It has a striking resemblance with “Polyporus cf vinosus” in Boldsystems. But what is it..?

Reminds me somewhat of
By: Gerhard Koller (Gerhard)
2013-02-05 13:02:42 -05 (-0500)

Polyporus pseudobetulinus which I found in Scandinavia and whose host is mainly birch and cottonwoods. Will post my find later on.

perhaps the same
By: Danny Newman (myxomop)
2012-09-08 03:17:01 -05 (-0500)
By: Danny Newman (myxomop)
2011-08-17 04:29:20 -05 (-0500)




By: Danny Newman (myxomop)
2011-04-10 03:15:36 -05 (-0500)

about 5-10 yards from the trail on a piece of wood about three inches thick; a branch from a much larger nearby tree most likely, unless it was driftwood. the degree of decomposition and similar shape and color when compared with other fallen forest debris lead me to believe it didn’t come from too far away. as evidenced by the pictures, the stipe location was central but the attachment to the substrate was lateral.

By: Sava Krstic (sava)
2011-04-09 23:58:59 -05 (-0500)

It was not near the trail. The branch was at least 10 cm wide, and it was horizontal. Myxomop: correct if I got something wrong here.

“Radially fibrilose”
By: Daniel B. Wheeler (Tuberale)
2011-04-09 07:12:02 -05 (-0500)

seems a very good description to me, myxomop and sava. The scales appear fine, appressed and hair-like to my eye. At nearly 2 inches width the specimen is on the small side for many of the branch-colonizing Polyporus I find in the Columbia River Gorge area. Usually those species are found on small-diameter Vine maple instead of cottonwood. The description of P. decurrens would seem to have too wide a stipe, but also too short. Was this growing from the side or underside of the cottonwood branch? In other words, did something roll the branch causing something like a stipe deformation? Near a well-travelled trail perhaps?

i stand corrected
By: Danny Newman (myxomop)
2011-04-09 02:17:05 -05 (-0500)

but certainly nothing approaching the erect scales that any MO or googlable images show.

Fine scales
By: Sava Krstic (sava)
2011-04-09 01:48:31 -05 (-0500)

… (or hairs) were there actually, visible under hand lens.

no scales
By: Danny Newman (myxomop)
2011-04-09 01:29:54 -05 (-0500)

nothing appressed, really. To the touch the cap surface was smooth and unornamented. To the eye it has the appearance of texture, looking a bit radially fibrilose, but it’s an illusion. a lot like the concentric zonation of a Lactarius.

edit: IF suggests synonymy with Bjerkandera fumosa, which is no way a fit for this. the earliest description (1903), and the one not synonymized with B. fumosa (not sure how that works) has this to say:

of what I can understand/translate, i find the following contradictions:

1. “1/2mm-wide pores”. this ob’s are much smaller.
2. “3mm sub-bulbous base”. this one tapers and is generally unremarkable aside from the color variation, of which there is no mention (I don’t think).

I would call P. decurrens
By: Daniel B. Wheeler (Tuberale)
2011-04-08 18:57:28 -05 (-0500)

but have NOT seen this species before. Described in Arora from CA and WA (don’t know why OR missing), said to fruit usually on or near rotting wood, and I don’t see why it couldn’t be on cottonwood. Does not have the tiny upright stature of P. badius nor the black stipe. Specimen could be young, but flattened scales on cap suggest to me an older specimen. Specimen seems a little thicker than P. elegans should be, but with less stipe than I would recognize.

i think
By: Danny Newman (myxomop)
2011-04-05 13:54:37 -05 (-0500)

we’ve got the “difficult do discover” part down flat.

I was instantly reminded of http://mushroomobserver.org/8785 when we stumbled across this. Same extremely fine and acutely decurrent pores.

By: Irene Andersson (irenea)
2011-04-05 13:10:59 -05 (-0500)

looks like some kind of worm there :-)

Polyporus should have smooth, almost banana-shaped and colourless spores (the size varies with species, of course). They are thin-walled and can be difficult to discover.

I’m seeing things
By: Sava Krstic (sava)
2011-04-05 02:05:58 -05 (-0500)

… that don’t exist. I cleaned my instruments, prepared a new slide, and found an ascus! (Last pic.) Now, I need a glass of brandy; don’t dare to look anymore.

Thanks, Irene. I think I need to wash my plastic mushroom box.

Don’t eliminate Polyporus yet
By: Irene Andersson (irenea)
2011-04-05 01:17:30 -05 (-0500)

Polypores in general are hopeless in the microscope.. They tend to collect lots of other things from the surroundings. This may still be immature, and the spores you found probably belong to something else.

By: Sava Krstic (sava)
2011-04-05 00:53:38 -05 (-0500)

Irene, thanks for your attempts. Last night I coudn’t find anything interesting under the scope. Better luck now, but I still cannot fully match it with anything.
Do rough spores eliminate Polyporus?

At least 5 pores per mm.

1000x, in KOH/Congo Red. Spores 9-11 × 5-6 microns. Clamp connections observed in 3 places. Some hyphal ends enlarged. Couldn’t see any basidia.

Added a picture
By: Sava Krstic (sava)
2011-04-03 14:08:54 -05 (-0500)

… with more realistic colors.

Context is white; pores tiny, white. Odor mild, pleasant. Taste mild.

Created: 2011-04-03 00:23:01 -05 (-0500)
Last modified: 2013-02-06 01:19:53 -05 (-0500)
Viewed: 447 times, last viewed: 2018-03-01 04:19:20 -05 (-0500)
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