Growing on a concrete wall, dark brown crustose lichen with a cracked thallus and some slightly lighter brown areas. Possibly Acarospora?
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 this is most likely to be A. fuscata, but would prefer a closer look.
Its unlikely to be Acarospora fuscata as its on concrete - Verrucaria nigrescens possibly but hard to tell from the photograph
I somehow managed to miss the fact that it's on concrete. Should read more carefully!
Too pale for V. nigrescens? I might have agreed with V. macrostoma if the perithecia were evident.
Thank you all for your suggestions. I have asked my son if he could take a better photo for us so that more detail can be seen.
When I get it, would it be best to put the newer pic here or as a separate observation?
add the pic to this observation.
The perithecia, if present, will be around 0.4mm across and not the easiest of things to photograph. You may have seen the dome-like structures on Verrucaria (Hydropunctaria) maura.
Microscopy might be needed for certainty to decide between V. macrostoma and V. nigrescens. I have only seen the latter.
My first guess would be V. fusconigrescens - it looks the right colour for the usual form of this (not the variant in Dobson!), and it would appear to be plentiful in the south-west. But detailed examination needed. Doesn't look like V. macrostoma to me.
I've had a look at the photos of V.fusconigrescens on http://www.irishlichens.ie/pages-lichen/l-162.html and think that the newer photos I posted here match better colourwise at least.
My son owns a microscope (whereas I do not) and maybe would be able to look more closely. What would a detailed examination entail?
Four new photos added that were taken this morning. The sunlight was bright and it seems to have made quite a difference to the colour, the brown appearing much greyer. I hope they may make identification a little easier.
Lat/Lng: 50.6, -4.2
OS grid ref: SX4588