I think the white (there were many like this) were caused by the weather. Please let me know if you think otherwise.
On Helliborus (Christmas rose)
IN Europe, othe species are also noted, such as Coniothyrium delacroixii and Coniothyrium olympicum.
According to the USDA Mycological Herbarium database:
https://nt.ars-grin.gov/fungaldatabases/specimens/new_frameSpecimenReport.cfm
I'm not very happy with this ID becuase I can not find any info on the cell or leaf sizes of this species.
Leaves are .75 x .25, medial cells average 30X5. Growing on a big leaf maple tree next to a river. There was not much of it there so maybe this is not a very good sample.
@tiwane @kueda @carrieseltzer did this generate notifications for you? see https://www.inaturalist.org/observations/19735072#activity_comment_4753696