Heterotheca villosa?

Or Sycamore?

Here is a link that might be useful: {{gwi:163066}}

Elecampane?

FataMorgana

so many seeds look like that! like fatamorgana i'm guessing an aster family member

Nerium oleander?

pretty sure its oleander! i got some too from someone in the seed exchange forum

I used to see seeds like that in my hometown. They were the seeds of Platanus ÃÂ acerifolia, as shown in the following link:

http://oregonstate.edu/dept/ldplants/plac14.htm

Of course it's also possible that other trees have similar seeds.