split at the surface

Sectioned at the core. I found these under a slender tree behind the Vanderbilt St. Playground, near that small mounded area where kids often build lean-tos with sticks. Thought they were acorns at first until I saw they had no stylish cap and bore a pentacle of cracks at the bottom. I'm wondering if the five-sectioned fruit developed from a five-petaled flower.

I've learned that long before the pentacle became associated with things demonic it was viewed by Greeks as very auspicious, symbolizing the spirit bringing the elements into natural harmony, the opposite of chaos; a concept taught by Empedocles, ca. 475 BC, and it was also associated with Persephone, who represented the spirit of grain. To the Egyptians the star represented an underworld womb and was associated with Isis and her twin Nephthys. One could also just call the fruit cinquefoil and invite an alternate set of associations.

Update: Tree Specialists associated with the Prospect Park Alliance report that these look like the seed capsules of a Franklinia Tree. My belated but sincere thanks!!