The tree on the right is an Ecuador pink and the one on the left is Frosty Pink. Both of these lose the sepal/calyx shortly after the corolla falls off, whether they were pollinated or not. One can watch these develop 'out in the open' so to speak. When I saw the calyx turn yellow and fall off, I was so surprised to see a little seed pod there. They are still growing. Some pods are larger, just used up all the space on the disc before I got all the photos I wanted. Couldn't even get one of Nana, cause the disc was full.
