Our mystery samaras last week were (as Sara suggested) from a tulip tree, Liriodendron tulipifera.
(Photograph in the public domain by P.Gibellini at Wikimedia)
The scientific species name means "tulip bearing" and refers to the stunning yellow and orange cup-shaped flowers...
Tulip trees are large, beautiful deciduous natives to the East Coast of North America.
Have you ever seen a tulip tree flowering? What do you think of them?