@pmurphy posted a photo of Prunus x kerrasis 'Cupid' at Virtual Garden Tour. I had never hear of these, have now learned that they are a cross between Prunus cerasus and P. fruiticosa, and their advantages are that they have a high brix content for sour cherries and they are well-adapted for use by machine harvesters. Here is a lot of information packed into one page: Canadian Dwarf Sour Cherries – Prunus x kerrasis — Carrington REC (ndsu.edu). There are links from there to the U. of Saskatchewan Fruit Program page at Sour Cherries - University of Saskatchewan Fruit Program - University of Saskatchewan (usask.ca), which links to a more extensive history at Tarts with a touch of romance | Good Fruit Grower.
