Unidentified fungus on oak log

[Bruce Williams]

Salcey Forest, Northants - 23rd Feb. Growing on underside of oak log. Please note scale bar on both pics.

Help with identification appreciated.

Bruce

[CapAndBracket]

Could i start the suggestions with the Sulphur knight Tricholoma sulphureum.

Cheers J.P.

[Fungus Ken]

For me, a couple of things would rule out Tricholoma. First the habitat on wood. Species of Tricholoma are all mycorrhizal so the mycelium would be growing in the soil in association with tree roots rather than in wood. You would not expect the "fruiting bodies" to be growing out of wood if it was Tricholoma.

Also there is partial veil still visible in the form of a web-like cortina joining the edge of the cap to the stem. No species of Tricholoma would show a distinctive cortina like this. (Tricholoma cingulatum does have a partial veil that forms a ring on the stem but it would be more membranous.)

My starting point would probably be Gymnopilus but that's as far as I could take it.

Ken

[PMG]

Am I being over obvious but what about Gymnopilus penetrans anyone? Or have I missed something..........

Pauline

[Fungus Ken]

Originally Posted by PMG

Am I being over obvious but what about Gymnopilus penetrans anyone? Or have I missed something..........

Pauline

I'd say the latter. Gymnopilus penetrans is very common, but let me give you a description of a possible alternative from Courtecuisse (to use a book that many people will have):

Gymnopilus hybridus - gills not spotted, pale yellow then russet. Stipe with a persistent white or silvery cortina, forming a pale ring. Flesh white or very pale, bitter. Habitat twigs and woody debris under broadleaved trees and conifers.

Now tell me why it is Gymnopilus penetrans rather than Gymnopilus hybridus. The spotting on the gills in the former would only become apparent with age, as would the presence or absence of a persistent cortina.

So with a young specimen like this it is impossible (or more correctly I don't know how) to separate these species by eye.

Ken

[CapAndBracket]

You quite rightly mention the two points that i was ignoring, i hope Bruce can take another photo of the situation in a weeks time, the answer will be very interesting.
Nice to see i'm not the only one who looks under wood.

Cheers J.P.

[Fungus Ken]

The benefit of people posting their suggestions on the forum, whether right or wrong, is the chance for others to present their thoughts on why the suggestions might or might not be right, which leads to a healthy debate.

It gets a bit boring if someone puts up their mystery image and the next five posts all just say: "This is x species" without explaining why.

Ken

[cybershot]

....and not nearly so beneficial, edumerkashunally speaking

[Bruce Williams]

Thanks for your help and interesting comments everyone - all much appreciated.

J.P. - Unfortunately there's not much chance that I could find that log again.

So am I right in thinking that the consensus view is Gymnopilus species with both G. penetrans and G. hybridus as possibles?

Bruce

[Fungus Ken]

Originally Posted by Bruce Williams

So am I right in thinking that the consensus view is Gymnopilus species with both G. penetrans and G. hybridus as possibles?

Bruce

I don't know how many people it takes to reach a consensus but that would be my view.

That said, if I were in a less facetious mood I'd agree with Pauline that you could safely put this down as Gymnopilus penetrans... if you take a fairly broad concept of this species.

Some authors do not regard Gymnopilus hybridus as a separate species and, although it is included in the Basidiomycota Checklist, here is what the Checklist has to say about it:

"Habitat: On fallen and decayed wood of deciduous trees such as Betula, Fagus and Quercus spp. Rarely reported on conifers.

Notes: A nomen dubium lacking type material. Sensu Fries (1821) and sensu auct. is Gymnopilus penetrans."

I have found specimens that lacked rusty spotting on the gills and retained a lot of veil on the stem in the form of a whitish band, which I might have considered to be Gymnopilus hybridus. But I don't normally record anything as this species because I am not convinced that these are reliable characters for separating the two species.

Nordic Macromycetes 2 suggests they may just be different forms of a single variable species. Until someone provides us with the DNA evidence it's down to your own judgement as to whether you consider these (and one or two other very similar species) as separate.

Generally I only bring up Gymnopilus hybridus when I am feeling argumentative.

Ken