Phylum: Ascomycota Family: Incertae Sedis
Xanthoriicola physciae (Kalchbr.) D. Hawksw.
Lichenicolous fungus, mostly parasitic on Xanthoria parietina. Widespread
References:
Smith, et al., editors (2009) - The Lichens of Great Britain and Ireland;
Dobson (2018) - Lichens: an Illustrated Guide to the British and Irish Species