Late summer is a good time to collect graines a voler, the green seeds of the American water lotus plant. The graine a voler (french for “flying seed”) is a large, showy plant native to Louisiana’s freshwater marshes; 3′ wide lily pads held above the surface of the water produce longstemmed white lotus blossoms. After the flowers fade, a 4-6″ wide half-spherical seedpod forms–these pods are often dried & used in flower arrangements. As the pod dries, the seeds pop out with great force (hence the name).
Here’s an article from the Lafourche Daily Comet about the harvesting & eating of graines a voler in the freshwater marshes of Lafourche Parish; the article attributes this activity to Cajuns, but it is almost certainly a practice they learned from the native peoples who first lived in south Louisiana.
And here’s the USDA plant information database record on the water lotus, with lots of nifty info.