Plectranthus verticillatus or similar species.

Well, it must have been either a birds butt, or I carried it here myself, after walking in the woods. The pants I wear that can get dirty/muddy in the garden or on the trail tend to be the same pants. I should re-think that for the future. IâÂÂve soaked it, and soon will try pulling. Will probably be adding another thing to the list of garlic mustard and yellow woodsorrel, that I canâÂÂt get rid of. Sigh....

I found the genus on the Kansas Wildflowers site, and then identified the plant with the Arkansas Wildflowers key. This appears to be Erioganum longifolium (Longleaf Buckwheat). That genus is interesting. BONAP lists 230 Erioganum species, with all of them scattered over the western half of the country.

Cephalanthus?