It looks like a thyme which is absolutely desperate for more light. The pale leaves on weak, thin stems are symptoms of etiolation. You might also have a lot of separate plants in the pot from a cluster of seedlings.

Wow. Haven't been this stumped in a while. Gray aerial roots remind me of orchids, growth habit on new sprouts reminds me of Callisia fragrans/false bromeliad... the more I look at it, the more I think it might be some Callisia relation. Edit: Could you possibly provide photo of the entire plant in the pot?

It's a Bidens species. Most are very weedy and many have seeds that attach to clothing.

There was some of the yellow blooming ragweed in that area last year. That didn’t show up again. Better make sure this mugwort is not going to seed.