Identification: Prunus x gondouinii 'Schnee' - single white, green leaves, mid-to-late season

I guess these are just an Avium of some sort, based on the way the sepals curl back, but the shape of these trees seems different, they're grafted, and there doesn't seem to be any evidence of what else they were supposed to be unless I'm just not noticing a difference in different branches. The blossoms are larger than a quarter, and some were larger than the ones in the photo. The trees are on Bute just south of Davie in Vancouver's West End.

 

Re: Prunus Avium - Small singles, green leaves, large round tree, mid to late season

Looks like Prunus x gondouinii 'Schnee'. Prunus expert A.L. Jacobson has found this at a couple locations in Seattle:

...a sour / sweet cherry hybrid from Germany; schnee means snow in German. A nearly fruitless clone grown as an ornamental. It is extremely rare in Seattle. Green Lake has one in the NW part, next to the unpaved trail that goes from the parking lot to the huge boulder near the asphalt lakeside path: 22 1/2' x 3'6". High Point housing has some street-trees by 32nd Ave SW & SW Morgan St.

--Trees of Seattle - Second Edition