Looks like wisteria.

Aaaack. I always thought that stuff was Bougainvilla, but now that I look it up, yep, it's Wisteria. Many thanks.

I should add that I was looking up pictures of Bougainvilla seeds, and they sure didn't look anything like these. These seed pods are really tough. Need a pliers to break them open. I'm looking forward to planting them, probably down near their parent plant.

When the wisteria seeds are ripe, the pods open with a resounding crack and the seeds will be catapulted quite a distance.

Fascinating. But does that mean when one finds a dried seed pod with seeds in it, the seeds aren't yet ripe?

"I'm looking forward to planting them, probably down near their parent plant."

You may find that you already have seedlings scattered around since Wisteria has a reputation for producing seedlings at a rate that in some areas makes them a pest. The seed-grown plants take quite a number of years to bloom, so you would have to ID them by the leaves and vine itself.

"But does that mean when one finds a dried seed pod with seeds in it, the seeds aren't yet ripe?"

No, once the seed pods are dry, the seeds will be ripe. Probably the environmental conditions or pod age haven't been right for them to split open yet. Some plants won't pop open until it rains for instance.

If you've found the pods on the ground, they may have dropped off before maturing. I don't know why anyone would want to help spread a very invasive vine, but I would suggest collecting seeds in the summer, when they are popping open naturally.