Tree identification?

I'm afraid I'm not very good at identifying American trees. Can anyone identify this tree for me? It has quite large simple leaves, and also still had quite long seed pods hanging down in places. I took this in Swaim Park on my way back from swimming. It originally caught my eye, as the flowers are beginning to fall, and were scattered all around on the ground. The blue sky in the background was not typical of the day - it probably lasted no more than an hour! The rest of the day was grey, gloomy and threatening, though still warm. This evening it showered again. This has been the pattern for several days now. Tomorrow it is supposed to be better - let's hope!

One year ago: Lines and shadows