No common name
The Red Campion (Silene dioica) are in flower in the wood at the moment, and are quite a sight.
Scattered amongst them are a smaller number of White Campion (var. alba). Looking at them yesterday I noticed that some of these had unusually dark anthers.
This is the Anther Rust fungus, Microbotryum violacea.
Originally classified as a smut, it is now recognised as a rust fungus.