Perhaps one of the many Galium sp.

Looks like Sherardia arvensis to me.

Both answers are correct. I was relieved to learn this was Sherardia. I went through every species of Galium and nothing matched. Either it's not here in my local area, or I've been mistaking it for Galium. BONAP has this listed as Galium sherardia. That name,Galium sherardia was given by Krause in the nineteenth century. This species has had several names since including Asperula, [ 10 synonyms]. Linaeus, adapted the name, already given to it, in honor of William Sherard. Sherard was a botanist, and was classifying plants prior to Linaeus. I read that the flower color, flower shapes, and floral bracts of Sherardia were the reason it wasn't lumped into Galium' but I think the main difference is the floral bracts. I've seen photos of Galium species with red flowers, and then we have Galium trifidum with 3 petaled flowers, but still remaining in Galium? I don't see any significant difference in the flowers of Sherardia compared to Galium flowers, am I missing something? So, the question, are bracts more of a morphological leap then petal count, and deserving of a move to a monotypic genus? Cool link, if you like the history of taxonomy.

https://herbaria.plants.ox.ac.uk/bol/plants400/Profiles/st/Sherardia

BONAP Galium sherardia

Galium trifidum

Galium arkansanum

Wouldn't mind having this as a weed.

Weakley (2020) Flora of the Southeastern United States.

Galium sherardia. ...usually treated as a monotypic genus, buy Soza and Olmstead (2010) show Sherardia to be deeply embedded within a paraphyletic Galium.

Gerould Wilhelm ( Plants of the Chicago Region, Flora of the Chicago Region), Sherardia arvensis. Wilhelm also goes with Prenanthes instead of Nabalus. It's hard to decide which of two great botanists is more correct, but I usually side with Weakley, and most native plant people here in northern Illinois swear by Wilhelm, so I'background? Perenn gave the genus. So I have to wonder what Linnaeus would have named it, if he had encountered it as a new, unknown specimen? Galium bracteata? Galium verticillata? He might have even wanted to rename it back then, but didn't want to upset the guys who already had named it in another guy's honor.