acer

The seeds inclosed were the samaras of Acer rubrum, called the "soft" maple in many localities, and "red" maple in others.

It occurs on stumps and rotten logs of various sorts in the Mississippi valley, more often affecting stumps of Acer saccharinum L.

If you have been careful in your search you will finally stop at Acer saccharum.

The particular variety that is so used is of course the rock or sugar maple (acer saccharinum).