I am really stumped on this one, but Facelis retusa is one of the choices that came up. Edge of mowed athletic field
This plant appears not to have any leaves or nodes. The stem is D shape in cross section, mostly spongy with just a few vascular(?) bundles. It's about 2 feet tall but not woody - bright green all over -- stalks look like celery. I am stumped! Growing in roadside ditch.