Cloudy and dark.
Baeomyces rufus is a lichen that is commonly found on rocks and occasionally on stumps. The fruitbodies are pink - hence the specific name.
But occasionally, I'll find black and/or stunted fruitbodies. Lichens are a combination of fungus and alga(e), and there are lichenicolous fungi that attack them, so this appears to be a fungal attack.
Large areas of the thallus can be infected, with many dead or dying fruitbodies in evidence.
This is a particularly large infected fruitbody, at about 2mm tall.
I know of one lichenicolous fungus that attacks Baeomyces rufus: Arthrorhaphis grisea. Further research will reveal if this is what we're seeing here.
Cladonia portentosa is one of the more recognisable lichens, often growing low amongst heaths.
The yellow leaf belongs to Tormentil.
Another Cladonia was also growing on the stump. This looks to be close to Cladonia polydactyla.