https://forums.botanicalgarden.ubc.ca/threads/prunus-emarginata-pugetensis-cerasus-single-whites-in-clusters-very-late-season.26035/
Identification: - Prunus emarginata, pugetensis, cerasus - Single whites in clusters, very late...
[Edited by wcutler 20090515: This was labelled Prunus x pugetensis for about a year. I'm not convinced, and I have now merged it with another thread...
identificationprunuscerasus