I just saw Cephalanthus occidentalis at Houston Botanic Garden in Texas. I first posted this at https://forums.botanicalgarden.ubc....2014-where-are-the-flowers.84259/#post-365361 - @Nadia White Rock had posted what she thought were buds, was interested to see the flowers. Now I've caught the flowers looking their best.
Your photos bring back memories of my childhood, when I was fortunate enough to spend summers in New Hampshire. I thought these flowers were so cool---alien yet friendly, and unique. Still do!