Honey fungus rhizomorphs for ID

[lipase]

I've spotted what look like honey fungus rhizomorphs growing under the bark of an oak tree (I think). It does look similar to the black 'bootlaces' on the picture I've attached but they seem quite brittle, almost like the brittleness of dry strands of paint. I haven't found any information on the internet or elsewhere about how to positively identify honey fungus rhizomorphs. For example, could it just be a parasitic plants roots or perhaps a different type of tree dwelling fungus?

[lipase]

oops forgot this...

just to clarify; this isn't a picture of the 'rhizomorphs' I found, just a photo of a similar looking phenomenon I found on the web

[lipase]

Here's the possible armillaria rhizomorphs I found, sorry the photo's taken so long!

[Chris Yeates]

that's Armillaria mellea (in the broad sense) all right . . .

cheers

Chris