Does anyone know of a good key for identifying plants in this genus? I have pics but I'm not sure which characteristics are the most important for determining which species is which....or is this one of those plants where one should stop at the genus because it's virtually impossible to separate the species?

Thanks for any input!

I *thought* I had Desmodium canadense but then I looked at Desmodium glabellum....they all look the same!

Well, in case anyone else is ever searching for help with Desmodium sp. and you're in the East or Illinois (we have significant species overlap) these sites are very helpful! I think I have panicled tick trefoil

https://gobotany.newenglandwil...

http://www.illinoiswildflowers...