Botanical Mystery

We have this wild tropical looking tree out back, thriving in a dense understory of mature oaks and tulip trees. It grows huge leaves in an umbrella-like formation near the end of each branch. The leaves are about 2' in length and 10" wide. They are slightly ovoid in shape with the widest section falling closer to the end than to the stem. Last year, I thought we had successfully identified it as a pawpaw even though we had never seen a flower or a fruit. Most paw paws are not capable of self-pollination within an individual tree or a variety, so the lack of fruit was not surprising. I put 2 additional paw paws in the vicinity and hoped for better results this year. All three trees survived our winter of nonstop blizzards although we lost the top of the large tree. Much earlier this Spring, I was excited to find a flower on one of my new little pawpaw trees. It looked exactly it was supposed to brownish-red, bell-shaped about 1.5" in diameter and length and formed on the main stem of the tree. Now, a couple months later, I have this spectacular white beauty on the large old tree, which has never flowered before. This thing is creamy white with a splash of red in the center surrounded by 5 petals. It is at least the size of a dinner plate and has a large bulbous stile. It is similar in size and color to the flower of a southern magnolia, which its leaves also superficially resemble. However, the magnolia flower is more complex with an interior and exterior array of petals. The leaves of the 2 trees are superficially similar but very different; they are much large, soft, and pliable, not at all waxy, leathery, and firm like those of the magnolia. The tree is also deciduous, as are the two newly planted ones. The leaves are quite similar to the 2 new paw paws, except they are about twice the size and grow in a whirl toward the end of each branch rather than alternately along the branches. It occurred to me that these could be legitimate examples of male and female paw paw flowers, but the timing of the inflorescence remains confounding. Cross pollination among these trees will be impossible if blooms continue to occur months apart. So this one remains a mystery for now.