The contents of a pod. You will note that there are winged seeds here and other bits. These other bits are infertile seeds. This source: “The infertile seeds found in each of the sweet gum’s compound seed capsules are a naturally occurring source of shikimic acid, one of the main ingredients in the manufacture of Tamiflu.”
Winter birds, especially finches, flock over the pods to prize out these tidbits.
Plantphobes despair of the seed pods, believing they’re messy and dangerous, but the resin is famous. It’s the source of the binomial Liquidambar styraciflua, which is a bit redundant: the words mean liquid amber and flowing gum.
*Caveat on that “quite distinctive” — Green-Wood does have at least three Liquidambar acalycina, a tree native to China. On Thursday, I will compare these two species…
Backyard and Beyond 
The shape of Sweet Gum seed pods remind me of the Covid 19 virus. Both are interesting delivery systems. The tree has a pod which well protects the seed until it is ripe. Then the pods open and some seed drops. Other seed is retained within reach of the wide dispersal system, birds. After the pod drops its ball shape allows it to roll and dump any remaining seeds. All of this happens after most other trees have yeilded their mast and gone dormant. Perhaps this is to focus birds’ attention on the dispersal. Nature is always both more complex and more simple than it first appears.