Looks like what we have always called "beggar lice". The seed pods stick to clothes (and arms & legs) like Velcro.

Desmodium?

Thank you both. You agree because the popular name for desmodium is "beggar lice". There's a long list of varieties. The leaves on the growing plants I've seen look to be d. triflorum.

When I was a kid (many years ago) we spent our summers playing
"in the woods" and time back home picking off the "stickers" from ourselves and the dog. They looked just like some of the seeds I've seen of the various desmodium varieties. I feel like I've come full circle!

try getting that out of your yard. Hah! it laughs a herbicide. you have to use napalm and even then you must make more that one application.

Just be aware that Beggar's Tick is one of the host plants for the Longtail Skipper Butterfly. I let it grow amongst my turfgrass since it doesn't seem to bother it and I let it grow in some tucked corners, but I pull it from more visible, open spaces of my beds.