Observation 66889: Phlebiopsis gigantea (Fr.) Jülich

This seems like it should be a Peniophora based on the SV+ gloeocystidia, and the impressive lamprocystida However, I could not find clamps and the spores are small (5.4-6.2 X 2.8-3.1)l for at least the European clampless species. Basidia are long and thin (34 X4) with no clamp that I could find at the bottom, but I never got an ideal view because the hymenium was too tough to squish and too rubbery to cut thinly. This may improve after drying. The gray velvety look of the hymenium is caused by the cystidia, and this is apparently common in Peniophora. Some of the lamprocystidia were over 100 um in length. It was fruiting on the bark of a downed white fir or sugar pine log.

I sent this link to Karen Nakasone and she had the following comments, and I added the squash mount in phloxine at her request:

“I’m not sure that there are gloeocystidia. I didn’t see a sulfovanillin reaction in that photo like was anticipating. The times I’ve done the reaction, the color change is really obvious – a dark black to brown coloration. The cross section of the hymenium reminded me of a phanerochaete-like fungus. So maybe there aren’t any clamps…. The spores are not the right shape for Peniophora sensu stricto – they should be more allantoid and curved also most true Peniophoras have brown pigmented hyphae at least those next to the substrate. Also the texture you described – rubbery— doesn’t sound like Peniophora s.s.
I would like to see a squash mount of a thin section in phloxine.” – Karen

Karen pointed me toward the P. velutina or P. sordida, the size of the cystidia pushed it toward velutina, but the color of the fruitbody and the shape of the apex of the cystidia seemed wrong. She wrote the following in response to this:

Karen Nakosone: “There just aren’t too many options with large, heavily encrusted cystidia without clamps. Did you consider Phlebiopsis gigantea? It is ceraceous when fresh but quite tough and corneous when dried. At least well-developed specimens, cut edges have a tendency to curl away from the substrate. The cystidia and spores are within the right range.”

The dried texture is definitely very tough, and all the microscopic features fit, and so I just changed the name.

Species Lists


a dissecting scope view of the hymenium showing the projecting lamprocystidia
projecting lamprocystidia
Sulfovanillin staining of gloeosystem – Karen Nakasone looked at this and said this was not a positive staining, and that Gloeocystidida are not obvious, and on reflection she is correct.
spores 5.4-6 X 3.1 in KOH congo red
The margin of parts of the fruitbody had this nice fringe of hyphae, but most margins were more abrupt.
Basidium in phloxine
Squash of hymenium stained in phloxine after drying – no gloeocystidia are obvious, and now I’m am more sure of the lack of clamps.
sharp tip of lamprocystidium – this is the one feature of this specimen that does not fit well with Phanaerochatae velutina.

Proposed Names

-55% (1)
Used references: Corticiaceae of Europe
Based on microscopic features: presence of metuloids, and sulphovanillin positive gloeohyphae
61% (2)
Eye3 Eyes3
Based on microscopic features: a revised assessment of the SV reaction, the lack of clamps and the shape of the spores, the shape of the cystidia, and the texture of the dried specimen – see Karen Nakasone’s comments in the main description box

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
in working
By: Danny Newman (myxomop)
2017-02-16 10:16:00 CST (-0500)

on another crust observation, I’m finding it difficult to get clear definitions for metuloids vs. lamprocystidia. the observation in question (Observation 269949) has pretty similar cystidia as seen here.

By: BlueCanoe
2011-05-03 17:31:11 CDT (-0400)

The bark looks like sugar pine (Pinus lambertiana) to me. Orange-colored plates decomposing into “chippy” scales which then flake off. Compare to white fir (Abies concolor) which is gray-colored and more “chunky” or corky.

Created: 2011-05-03 15:36:18 CDT (-0400)
Last modified: 2011-05-06 18:28:10 CDT (-0400)
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