This spring I had about twenty dried fruits of P. incarnata; I planted all the seeds and got maybe 10 sprouts in all! It's my belief that the seeds are designed to pass through the GI tract of a small animal before a majority will germinate. The most likely candidates are raccoons, oppossums, or skunks. If anyone on this forum has, or knows someone who has, one of these animals for a pet, I will send you some ripe fruits if you will test this hypothesis by recovering the seed from the scat and planting it! Or by planting the scat itself, since in nature nobody gets the seeds out of the scat!

There is precedent for this hypothesis. A botanist on Mauritius, the island in the Indian Ocean where the dodo lived, noticed that one species of tree had no individuals less than about 300 years old, which is to say about the time the dodo went extinct. He force fed some seeds to a turkey and Voila!!! Germination!!