Thanks so much! Looking at pictures online, especially of the seed, it certainly looks like that's what it is.
The reason I am concerned is that to me it is vaguely reminiscent of Japanese Knotweed (fallopia japonica) which is very invasive where I live in...
In a recent trip to Central America, I came home with a few hibiscus seeds, a couple "nance" fruit seeds, a bunch of celosia seeds, and one...
My first guess is Norway Maple, http://en.wikipedia.org/wiki/Acer_platanoides
