Black powdery thallus growing on aluminium hand rail on footbridge over dual carriageway. Back leceidine apothecia. Possibly Scoliciosporum umbrinum.
Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
I think you are right about this, but I confess I have not yet checked my own collections of this microscopically, to be sure my own concept is right. Consequently, I am reluctant to comment on others' photographs of it - the downside (in this case!) of my 'expert' badge is that I may trump other, better suggestons.
The spores should be twisted and multiseptate.
Many thanks for help and information. It's encouraging to find out that the thinking may well be along the right lines (and helpful, of course, to find out when the thinking is definitely not along the right lines).
Lat/Lng: 50.8624, -0.0773
OS grid ref: TQ354087