The peduncles are much more prominent in Shiro-fugen. Isn't that the pedicels you've circled on the Kanzan?
No, the flowers are covering the pedicels. It's kind of a drag that the photos are on a different page now. I'm going to put my photo (well, your photo, my circles) here again. In the right circle, the top of the pedicels are just below the circle. In the inflorescence above the right circle, you see the peduncle with one pedicel heading down from that; the other pedicels are hidden.
The whole of Montgomery Park (W.43 to W.45, west of Oak to Montgomery) has been fenced around and is obviously under re-development, as shown in the photo below. The four Choshu-hizakura trees have been removed. Their Blooming ID 3665 should be updated. February 17, 2021.