The past couple days, I was in Los Angeles. I failed to get a photo of a type of tree, riding on the train. It was not one of the more common trees planted, but I saw a couple dozen. It's now October, and the tree was in bloom. Not sporadic, but a lot of flowers. The flowers looked sort of dark pink, multi-petal - single rosette is appeared. Maybe 3" diameter. Sort of reminded me of Magnolia stellata - the flower shape. Now - that's as I saw it from 50 to 200 feet away going 30 miles per hour. These trees ranged from about 15 feet to 35 feet tall. Very handsome looking tree. Round-headed form. Any ideas without a photo? It's the only tree like it there - nothing else came close, not even another tree in bloom that had orange pom-pom flowers.
From just the one photo, I was not able to tell. But after entering that name, and looking at several photos of the flowers and the tree form using Google images, yes, its very possible that its the bauhinia purpurea which you mentioned.