Weed ID ????

Got a small spot I've been bush hogging for several years, got some equipment wrecking debri out of it and think I might want to try to glean a
cut of hay from it late this summer.

I bush hogged it several weeks ago and last week hit it with some 2,4-D. The 2,4-D pretty much got everything, except this weed. It was only
slightly burnt. What is this weed and what spray can I use to get rid of it and still cut hay in late August?





Thanks!
Bill

Weed ID ????