I was making a quick visit to Drumboe Wood in Ballybofey today and I took some pictures of various parasites on Holly (Leaf-miners, weevils, that sort of thing). Suddenly I noticed this fungal rust on a few of the leaves and thought "Hmmm...never seen a rust on Holly before".
- there are no documented fungi that grow on healthy Holly leaves
- there are no documented Puccinias that grow on Holly at all.
After consultation and internet research, it turns out that a new Holly Puccinia was discovered in Europe in 1977, so I need to track down its specification and see if it matches what I have.
Another possibility was the Phycopeltis algal infection that can grow on Holly leaves, but that's only on the surface: this clearly goes into the leaf, as evidenced by the dark ring around the infection.
It's an Irish first, whatever it is.
This is the kind of thing that keeps me going: amateurs can still discover new things in new places....wonderful.