Mystery seed floret

[Low Altitude]

Anyone have an idea what these might be?

L to R: outside of 'floret'; inside of floret cut longitudinally; individual seed 'vanes'.

I picked them up from a forest floor in Eastern New York State, USA. I looked around but there were many, widely scattered, and i couldn't determine which of the surrounding trees and bushes was most likely to have produced them.

They were completely dry. I soaked some of the seeds for days and planted them. Several tries. Can't get them to germinate. I suppose they could have been on the forest floor for a hundred years, who knows?

Any clues gratefully received.

 

[Mrsclem]

Liriodendron- Tulip poplar. My yard is full of them!

 

[Low Altitude]

Oh Mrsclem, THANK YOU! Superb! That's them, no question. And with your lead, I found this page about propagation, which led to a page about 'stratification', about which I'm learning for the first time.

And that stratification seems crucial – it may well explain why my seeds haven't grown. I'm going to need to put them in damp soil for 10 days in the fridge. The explanation – mimic winter – makes perfect botany sense, but honestly, who'd have guessed?

It looks like a lovely tree. Well done your yard! I will follow the instrux and let you and everyone here know if it works. I'm a city apartment dweller and it might seem silly trying to grow trees, but hey, if it works, I'll try and bonsai them or something.

Thanks so much.